RIKEN
Accelerator
Progress Report

2004
vol.

38

BOOK & CD−ROM
RIKEN

CONTENTS
I.

Page
PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1

II.

OPERATION OF ACCELERATORSIII.

RILAC operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

RRC and AVF operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Cogeneration system operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

Operation of the tandem accelerator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

RESEARCH ACTIVITIES

1. Nuclear Physics
Decay modes of heavy and superheavy nuclei . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9Variational calculations of nuclear equation of state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10Importance of prolate neutrino radiation in core-collapse supernovae . . . . . . . . . . . . . . . . . .

11Study of supernova explosions with neutrino-transfer hydrodynamics . . . . . . . . . . . . . . . . . .

12

Neutron star matter in a chiral quark theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13Linear response theory in the continuum for deformed nuclei: Green’s function vsabsorbing-boundary condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14

Molecular structures of excited 10 Be and nucleon transfer in α + 6 He scattering . . . . . . .

15

Fusion reaction of halo nuclei . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16

Microscopic study of 16 C + 208 Pb inelastic scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

17

Nuclear radius deduced from proton diﬀraction by a black nucleus . . . . . . . . . . . . . . . . . . . .

18

Variation after parity projection calculation with Skyrme interaction for light nuclei . . .

19

Direct inclusion of the tensor contribution in the cluster model and mechanism of theappearance of cluster structure in light nuclei . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

20

Cluster-shell competition in light nuclei . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21

Eﬀects of ground-state correlations beyond RPA in light exotic nuclei . . . . . . . . . . . . . . . . .

22Particle-number conservation in the self-consistent random-phase approximation . . . . . .

23

8 Be in the charge- and parity-projected Hartree-Fock method.........................

24

Systematic study of E2 transition strengths of C isotopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

25

Study of unstable nuclei with an extended cluster-orbital shell model . . . . . . . . . . . . . . . . . .

26

Dominance of intruder state in 30 Na . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

27

Low-lying collective vibrational excitations induced by pairing anti-halo eﬀect . . . . . . . . .

28

A search for a uniﬁed eﬀective interaction for Monte Carlo shell model calculations(VI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

29

Hartree-Fock calculation of three-dimensional nuclear rotation . . . . . . . . . . . . . . . . . . . . . . . .

30

Symmetry in random matrix theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

31

Strange tribaryons as K̄-mediated dense nuclear systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

32

Spin dependent nuclear structure functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

33

Chiral symmetry in light-cone ﬁeld theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

34

Tensor analyzing power for the d + α backward scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35

Absolute calibration of proton polarization via p + 4 He elastic scattering . . . . . . . . . . . . . .

36

Breakup reactions of 11 Li . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

38

Coulomb and nuclear breakup of a halo nucleus 11 Be . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

39

Coulomb and nuclear breakup of 14 Be . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

40

Lifetime of the ﬁrst excited state of 12 Be . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

41

In-beam γ-ray spectroscopy of neutron-rich boron isotopes 15 B and 17 B via inelastic
scattering on 12 C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

42

16 C . . . . . . . . . . . . . . . . . . . . . . . . . .
Anomalously hindered E2 strength B(E2; 2+ → 0+
g.s. ) in

43

18 C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lifetime measurement of 2+
1 state in44

Low-lying excited states of 17 C and 19 C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45

Decoupling of valence neutrons from the core in 16 C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

46

Density distribution of 17 B studied via its reaction cross section measurement . . . . . . . . .

47

Isoscalar electric multipole strength in 14 O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48

E1 strength of the subthreshold 3/2+ state in 15 O studied by Coulomb excitation . . . . .

49

Study of 22 O(d,p)23 O reaction in inverse kinematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

50

Proton single particle states in 23 F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

51

Bound excited states in 27 F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

52

In-beam gamma spectroscopy of 25 Ne via 26 Ne breakup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

53

First excited state in 23 Al with Coulomb dissociation method . . . . . . . . . . . . . . . . . . . . . . . . .

54

Measurement of momentum distribution and reaction cross section for proton-richnucleus 23 Al . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

55

Proton resonant states in 23 Al using a radioactive beam of 22 Mg . . . . . . . . . . . . . . . . . . . . . .

56

Study of proton resonant states in 22 Mg using radioactive beam of 21 Na . . . . . . . . . . . . . . .

57

Coulomb excitation of 20 Mg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

58

Elastic resonance scattering of 23 Mg+p . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

59

Measurements of magnetic moments of 30 Al and 32 Al . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60

Production of spin-polarized 33 Si beam for g-factor measurement . . . . . . . . . . . . . . . . . . . . . .

61

Investigation of ﬁrst excited state in 27 P for astrophysical interest . . . . . . . . . . . . . . . . . . . . .

62

Study of astrophysically important resonance states in 26 Si and 27 P using radioactive
ion beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

63

Systematic behavior of B(E2) for Tz = ±1 even-even nuclides studied by Coulomb
excitation of 46 Cr, 50 Fe, and 54 Ni . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

65

Proton inelastic scattering on 74 Ni . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

66

Excitation function measurement of neutron-rich Ti isotope by secondary fusion
reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

67

Search for high-spin isomers in N = 51 isotones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

68

Experiments on synthesis of isotope 277 112 by 208 Pb + 70 Zn reaction . . . . . . . . . . . . . . . . . .

69

Experiment on synthesis of element 113 in reaction 209 Bi(70 Zn,n)278 113 . . . . . . . . . . . . . . .

70Electron scattering from unstable nuclei by a novel SCRIT method (II) . . . . . . . . . . . . . . .

71

Production of low-energy RI beam 46 Ar for secondary fusion reaction . . . . . . . . . . . . . . . . .

72

Production of 39 Ar at the CRIB facility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

73

Magnetic-ﬁeld eﬀect in muon-catalyzed dt fusion in liquid and solid D/T mixtures . . . .

74

Muon catalyzed t-t fusion and muon transfer experiments using liquid and solid T2
targets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

75

Dimuon measurement in indium-indium collisions at the CERN/SPS . . . . . . . . . . . . . . . . . .

76

Experimental signature of in-medium mass modiﬁcation of ρ/ω/φ mesons at normal
nuclear density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

77

2. Atomic and Solid-State Physics
Time-delay-matrix analysis of resonance scattering: General theory andCoulomb-three-body systems with diverging background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

79

Apparent discrepancy between the complex-rotation and hyperspherical results now
resolved: e+ + He+ scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

80

Electron capture in H+ +NH2 collisions between 0.5 and 1.5 keV . . . . . . . . . . . . . . . . . . . . . . .

81

Charge transfer processes by proton in collisions with C2 H4 molecule below 10-keV . . . .

82

Transient ﬁeld of 24 Mg ions in Gd at high velocities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

83

Seismological analyses of acoustic emission in solids by 95 MeV/u Ar ions . . . . . . . . . . . . .

84

Eﬀect of GeV ion irradiation on magnetic property of equiatomic FeRh alloys . . . . . . . . .

85

Single-event burnout of super-junction power MOSFETs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

86

Ion-track continuum: Its ﬁnding and material dependence . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

87

Time-resolved luminescence spectra of ion-irradiated alpha-alumina in VUV region . . . .

89

Coincidence measurements between L X-rays and ﬁnal charge states of Ar ions after
passing Ni microcapillary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

90

Coincidence measurements of X rays and ﬁnal charge states of N ions transmitted throughNi microcapillaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

91

Single and double electron capture processes in slow N5+ -He collisions . . . . . . . . . . . . . . . .

92

Theoretical study of electron capture in collisions of C4+ with He . . . . . . . . . . . . . . . . . . . . .

93

Multiple-electron processes in close single collisions of Neq+ (q = 1, 2, and 3) with Ar at
5 keV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

94

Scheme for highly charged ion cooling with positron and electron . . . . . . . . . . . . . . . . . . . . . .

95

Conﬁnement of nonneutral plasma in superconducting quadrupole magnet forantihydrogen synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

96

Precision spectroscopy of Zeeman splittings of 9 Be+ 2 2 S1/2 hyperﬁne structure levels(III) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

97

Laser-induced ﬂuoresence spectra of alkaline-earth ion-helium exciplexes produced in cold
helium environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

98Long electronic spin relaxation time of Cs atoms in superﬂuid helium . . . . . . . . . . . . . . . . .

99

Development of optical detection technique for single spin in diamond N-V center . . . . .

100

Channelling studies on the lattice location of B atoms in graphite . . . . . . . . . . . . . . . . . . . . .

101µSR study on magnetism of organic Mott insulator having two-dimensional triangularlattice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

102

3. Radiochemistry and Nuclear Chemistry
Plans for superheavy-element chemistry in RIKEN: Development of gas-jet transportsystem coupled to GARIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

103

Radioactive tracers produced at RIKEN accelerator research facility and future RI
beam factory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

105

Extraction behavior of Zr and Hf into TBP from hydrochloric acid: Development of TBP
resin for reversed-phase extraction chromatography of element 104, rutherfordium . . . . .

107

Development of on-line solvent extraction system for heavy actinide elements . . . . . . . . . .

109

Reactions of 57 Mn implanted into solid oxygen (II) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

111

Development of 83 Kr Mössbauer Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

112

Eﬀects of carnosine (β-alanyl-L-histidine) on the absorption of iron in rats . . . . . . . . . . . .

113

Cannulation study on the absorption of iron in rats: Eﬀect of L-catechin as apolyphenol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

114

Inﬂuence of pantothenic deﬁciency on intestinal ﬂora in rats . . . . . . . . . . . . . . . . . . . . . . . . . . .

115

Eﬀect of pantotenic acid and pantethine in aging rats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

116

Brain uptake behavior of 24 Na, 28 Mg, 43 K and 47 Ca by intranasal administration . . . . . .

117

Preliminary study on 88 Y olfactory transport: Animal experiment . . . . . . . . . . . . . . . . . . . . .

118

Analysis of skin distribution of 65 Zn in hairless mice treated with 65 Zn-labeled zinccompounds by oral supplementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

119

Excretion rate of bio-trace elements in bile of rat under oxidative stress of
Se-deﬁciency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

120

Distributions of technetium and rhenium in radish plants grown in nutrient solution
culture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

121

Comparison of leaching and sorption behavior of various ions in soil-water system basedon ICP-MS and multitracer analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

122

Multitracer technique for studies of uptake and eﬄux of trace elements in culture cellline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

123

Iterative image reconstruction method for GREI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

124

Fourier analysis of back-projected images obtained by GREI system . . . . . . . . . . . . . . . . . . .

125

Motion correction method for γ-ray emission imaging (GREI) . . . . . . . . . . . . . . . . . . . . . . . . .

126

Current issues on application of γ-ray emission imaging GREI in nuclear medicine . . . .

127

4. Radiation Chemistry and Radiation Biology
Response of DNA repair proteins to heavy-ion-induced DNA damages . . . . . . . . . . . . . . . . .

129

Eﬀect of heavy-ion beam irradiation on mutation induction in Arabidopsis thaliana(II) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

130

Establishment of Arabidopsis thaliana lines mutagenized by heavy ion beamirradiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

131

Chlorophyll-deﬁcient mutants of rice induced by C-ion irradiation . . . . . . . . . . . . . . . . . . . . .

132

Biological eﬀects of heavy-ion-beam irradiation on turfgrass . . . . . . . . . . . . . . . . . . . . . . . . . . .

133

Isolation of heavy-ion induced mutants of sweet pepper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

134

Eﬀects of heavy-ion beam irradiation on in vitro shoots of Japanese pear ‘Nansui’ . . . . .

135

Development of male sterile mutant that lacks pollen-producing ability by heavy-ion
beam irradiation in pelargonium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

136

Characterization of sterile verbena cultivars produced by heavy-ion beam irradiation . .

137

Flower color mutation in spray-type chrysanthemum (Dendranthema grandiflorum(Ramat.) Kitamura) induced by heavy-ion beam irradiation . . . . . . . . . . . . . . . . . . . . . . . . . .

138

5. Instrumentation
Development of PHENIX silicon pixel detectors in ALICE-RIKEN collaboration . . . . . .

139

Development of large-area two-dimensional position-sensitive silicon detectors . . . . . . . . .

140

Application of ultrathin silicon detector in low energy nuclear reaction measurement . .

142

Energy resolution of superconducting series junction detector for heavy ions . . . . . . . . . . .

144

Measurements of energy resolution and position dependence of NaI(Tl) scintillators . . .

146

Calibration method for fast-neutron detector wall using cosmic rays . . . . . . . . . . . . . . . . . . .

148

Development of windowless solid hydrogen target . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

150

Polarization calibration of spin-exchange-type polarized 3 He target at RIKEN/CNS . . .

152

Relaxation of proton polarization in polarized target . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

154

Development of neutron polarimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

156

Determination of vector- and tensor-analysing powers in elastic deuteron-proton α)10 B∗ (2+ ) reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
scattering via 12 C(d,157

Development of extraction and neutralization system for atomic beam resonancemethod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

159

Space-charge eﬀects in a catcher gas cell of an rf ion guide . . . . . . . . . . . . . . . . . . . . . . . . . . . .

161

Development of RI Extraction System with Static Electric Field . . . . . . . . . . . . . . . . . . . . . .

163

Development of linear rf trap for multireﬂection time-of-ﬂight mass spectrometer . . . . . .

164

Development of low-energy RI transportation system with static electric ﬁeld in Ne
gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

166

Conﬁnement of large number of antiprotons and production of ultraslow antiproton
beam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

167

Development of collinear laser spectroscopy setup for Ni isotopes . . . . . . . . . . . . . . . . . . . . . .

168

Magneto-optical rotation eﬀect in Rb for EDM experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . .

169

Nondestructive intensity monitor for cyclotron beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

170

Beam test of magnetic spectrograph PA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

172

Low-energy radioisotope beam separator CRIB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

173

Performance of SAMURAI spectrometer in the QQQ-D mode . . . . . . . . . . . . . . . . . . . . . . . . .

174

Development of TOF spectrometer for use in experiments at RIPS . . . . . . . . . . . . . . . . . . . .

176

Simulation of particle trajectories for the TOF spectrometer . . . . . . . . . . . . . . . . . . . . . . . . . .

178

Network and computing environment for RIKEN accelerator research facility . . . . . . . . . .

180

6. RIKEN-BNL Collaboration
Global analysis of fragmentation functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

183

Single-inclusive cross sections and spin asymmetries in hadronic collisions . . . . . . . . . . . . .

184

Spin asymmetry for charged pion production at RHIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

185

Charm-associated W ± boson production at RHIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

186

Hydrodynamic afterburner for the color glass condensate at RHIC . . . . . . . . . . . . . . . . . . . .

187

Global analysis of nuclear data on structure functions F2A and Drell-Yan processes . . . .

188

Tau polarization in oscillation experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

189

Density matrix renormalization group in a two-dimensional λφ4 Hamiltonian latticemodel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

190

Impact parameter dependence in Balitsky-Kovchegov equation and Froissart bound . . .

191

Soft modes at the QCD critical point in the chiral quark model . . . . . . . . . . . . . . . . . . . . . . .

192

Melting pattern of diquark condensates in quark matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

193

Linking the chiral and deconﬁnement phase transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

194

Cut-oﬀ eﬀects in meson spectral functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

195

Matrix models and lattice simulations for QCD at nonzero density . . . . . . . . . . . . . . . . . . . .

196

Two-particle wave function with four-dimension Ising model . . . . . . . . . . . . . . . . . . . . . . . . . .

197

Penta-quark baryon in anisotropic lattice QCD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

198

Static quark potential in Nf = 2 dynamical domain-wall QCD . . . . . . . . . . . . . . . . . . . . . . . .

199

Nucleon structure in lattice QCD with domain wall fermions . . . . . . . . . . . . . . . . . . . . . . . . . .

200

Neutron electric dipole moment with domain wall quarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

201

The ﬁrst results of the dynamical domain wall QCD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

202

Perturbative determination of mass-dependent renormalization and improvement
coeﬃcients for the heavy-light vector and axial-vector currents with relativistic
heavy and domain-wall light quarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

203

Twisted mass QCD, O(a) improvement and Wilson chiral perturbation theory . . . . . . . .

204

Status of the QCDOC computer project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

205

PHENIX Run-4 achievments and future prospects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

206

Single transverse-spin asymmetry measurement in neutral pion and charged hadronproduction at PHENIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
√Measurement of prompt photons in s = 200 GeV pp collisions . . . . . . . . . . . . . . . . . . . . . . .
√Measurement of prompt photon cross section in proton-proton collisions at s = 200 GeV
by isolation cut method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

208
209
210

Measurement of double helicity asymmetry (ALL ) in π 0 production in proton-proton
collisions at RHIC-PHENIX experiment in Run 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
√J/ψ production in polarized proton-proton collision at s = 200 GeV with PHENIX . .
√Measurement of single electron spectrum in s = 200 GeV p-p collisions at
RHIC-PHENIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

212

J/Ψ production in p-p, d-Au and Au-Au and collisions in the PHENIX muon arms . . .

214Single electron measurement in the PHENIX Run3 d+Au experiment . . . . . . . . . . . . . . . . .

215

Radial ﬂow study via identiﬁed hadrons spectra in Au+Au collisions at
RHIC-PHENIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

216

211

213

Measurement of low-mass vector mesons in nuclear collisions at PHENIX . . . . . . . . . . . . .
√Charm Production in Au + Au collisions at sN N = 200 GeV . . . . . . . . . . . . . . . . . . . . . . . .

217

Muon trigger upgrade with muon cathode strip chambers . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

219

Multiparticle analysis for jet identiﬁcation at PHENIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
√Pentaquark search in sN N = 200 GeV Au+Au collisions at RHIC-PHENIX . . . . . . . . . .
√Pentaquark search in sN N = 200 GeV p + p and d+Au collisions at
RHIC-PHENIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
√Measurement of single electrons in sN N = 62.4 GeV Au-Au collisions at RHIC
PHENIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

220

218

221
222
223

Measurement of analyzing power in pp elastic scattering in peak CNI region withpolarized hydrogen gas jet target . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

224

Measurement of the analyzing power of proton-carbon elastic scattering in the CNI
region at RHIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

226

PHENIX silicon vertex detector upgrade project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

227

Evaluation of pixel read outchip of PHENIX silicon vertex upgrade . . . . . . . . . . . . . . . . . . .

228

Development of silicon pixel detectors for PHENIX at CERN . . . . . . . . . . . . . . . . . . . . . . . . .

230

Development of silicon stripixel detector for PHENIX silicon vertex tracker . . . . . . . . . . .

231

Aluminum bus development for silicon vertex detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

233

Evaluation of silicon strip sensor for PHENIX upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

235

PHENIX VTX simulation and reconstruction software (Status report) . . . . . . . . . . . . . . . .

236

Development of digital-pilot ASIC and data link system for PHENIX pixel detector . . .

237

Field measurements in AGS warm snake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

238

Forward muon trigger upgrade for PHENIX experiment at RHIC . . . . . . . . . . . . . . . . . . . . .

240

New scaler boards based on LBL/STAR design for PHENIX . . . . . . . . . . . . . . . . . . . . . . . . . .

241

DAQ system upgrade of optical alignment system at PHENIX muon tracker . . . . . . . . . .

243

Status of fragmentation function analysis at BELLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

245

Spin transfer to Λ+c hyperons in polarized proton collisions at RHIC . . . . . . . . . . . . . . . . . .

246

CCJ operation in 2003–2004 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

247

7. MiscellaneousIV.

Pumping 229m Th by hollow-cathode discharge [II] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

249

Carbon-nanoparticle formation from Teﬂon through rf-discharge processes . . . . . . . . . . . . .

250

DEVELOPMENT OF ACCELERATOR FACILITIES

Eﬀects of plasma electrode position on beam intensity and emittance of RIKEN
18 GHz ECRIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

251

Improvements in Hyper-ECR ion source for production of metallic ions and extractionof ion beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

253

A broadband cavity with magnetic alloy cores as buncher of ion beams . . . . . . . . . . . . . . . .

254

Status of control system for RARF and RIBF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

256

Field test of N-DIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

258

Remodeling of linear accelerator building for uranium acceleration . . . . . . . . . . . . . . . . . . . .

260

Measurements of long-term phase stability of RRC rf-system . . . . . . . . . . . . . . . . . . . . . . . . . .

262

Rotating carbon disk stripper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

264

Preparation of carbon foils by cracking using of methane gas . . . . . . . . . . . . . . . . . . . . . . . . . .

266

Response of imaging plate and X-ray ﬁlm to heavy-ion beam irradiation . . . . . . . . . . . . . .

268

Electrical power supply system for RI beam factory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

269

Cooling water system in RIKEN RI beam factory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

271

Improvements of a current and position monitor using HTS SQUIDs aiming at themeasurements of a 1 nA DC beam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

273

Beam quality estimation of RIBF accelerator complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

275

Status of ﬁxed-frequency Ring Cyclotron (fRC) in RIBF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

277

Design of vacuum system for RIKEN fRC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

279

V.

Construction status of IRC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

281

Status of magnets for the SRC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

283

Development of liquid helium ﬂow meter for the SRC magnets . . . . . . . . . . . . . . . . . . . . . . . .

285

Present status of liquid-helium supply and recovery system . . . . . . . . . . . . . . . . . . . . . . . . . . . .

286

Status of the BigRIPS separator project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

287

Stand-alone test operation of the BigRIPS liquid-helium cryogenic plant andheat-load measurement of its cryogenic-temperature transfer line . . . . . . . . . . . . . . . . . . . . . .

289

First stage of BigRIPS separator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

291

Design of focal-plane devices for BigRIPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

293

Laser-beam testing of prototype swirl-tube beam dump for BigRIPS separator . . . . . . . .

295

Development of production target for BigRIPS separator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

296

Design of RI-beam delivery line and zero-degree recoil separator . . . . . . . . . . . . . . . . . . . . . . .

297

Rf cavity with parallel-plate radial lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

299

High current RFQ linac . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

301

Proof examination of alternating-phase focusing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

303

Inductance calculation of helical conductors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

305

RADIATION MONITORING

Routine work for radiation safety in the ring cyclotron facility . . . . . . . . . . . . . . . . . . . . . . . . .

307

VI.

LIST OF PUBLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

309

VII.

LIST OF PREPRINTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

314

VIII.

PAPERS PRESENTED AT MEETINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

315

IX.

LIST OF SYMPOSIA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

323

X.

LIST OF SEMINARS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

326

XI.

LIST OF PERSONNEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

330

AUTHOR INDEX

Frontispiece: Figures for “Experiment on synthesis of element 113 in reaction 209 Bi(70 Zn, n)278 113”
(p. 70)Experiment on synthesis of element 113 in reaction 209 Bi(70 Zn, n)278 113—Newly discovered 113th element—(P. 70)Fig. 1. The most likely candidate event for the isotope of the 113th element, 278 113, andits daughter nuclei was observed, for the ﬁrst time, in the 209 Bi + 70 Zn reaction. The
measured energies and decay times are indicated in the ﬁgure.

Fig. 2. This ﬁgure shows a schematic view of the Gas-ﬁlled Recoil Ion Separator GARIS.
The GARIS is a separator for recoiling atoms with a large transport eﬃciency and a
low background.

2

Fig. 3. These ﬁgures show the gas-cooled rotating target system. The diameter of therotating wheel is 300 mm and the rotating speed is 3000 rpm. Helium gas in the
GARIS has two important roles, charge equilibration of recoiling ions, and cooling of
the target.

3

Fig. 4. These ﬁgures show the focal plane detectors installed in the detector chamber.
The detector system consists of two Time-of-Flight (TOF) detectors and a silicondetector box. The fusion product is implanted in the Position-Sensitive semiconductor
Detector (PSD) and mass information is obtained in combination with TOF andimplantation energy. The decaying alpha particle accompanied by implantation isdetected by PSD or PSD and the Side detector without a TOF signal.

4

RIKEN Accel. Prog. Rep. 38 (2005)

I. PREFACE

This issue of RIKEN Accelerator Progress Report reports on progress of research activities in the RIKEN
Accelerator Research Facility (RARF) up to October
2004. The research programs involve a variety of ﬁelds
such as experimental and theoretical nuclear physics,
nuclear chemistry, radiation biology, atomic physics,
condensed matter physics, plant mutation, material
characterization, application to space science, accelerator physics and engineering, laser technology, and computational technology in terms of accelerator or radiation application. These activities involved a few hundred researchers from domestic and foreign institutions
together with laboratories and Centers in RIKEN. The
spotlight is directed to the ﬁrst production and identiﬁcation of an isotope 278 113 of the 113th element, whichis the heaviest element ever created with conﬁrmation
by known α decay.
Major research activities of the RARF are based on
the heavy-ion accelerator complex consisting of theK = 540 MeV RIKEN Ring Cyclotron (RRC), theenergy variable heavy-ion linear accelerator (RILAC),
and the K = 70 MeV azimuthally varying ﬁeld cyclotron (AVF). Heavy-ion beams of a variety of elements with energies ranging from a few A MeV to135A MeV are provided. Vector and tensor polarized
deuterons are also available. The three accelerators
have been used in various conﬁgurations. The RRC operates either with the AVF or the RILAC as the injector. The AVF has been providing beams of ions of mass
numbers up to 60, whereas the RILAC can accelerateheavier ions. An energy booster called CSM (Charge
State Multiplier) installed in collaboration with CNS,
the University of Tokyo, is used to raise the maximum beam energy from the RILAC. This enabled
to deliver high-intensity beams of intermediate masselements such as Kr up to 64A MeV from RRC. In addition, RILAC and RRC can be operated separately,when the AVF is used to inject ions to the RRC. This
allows for long runs with RILAC beams like the experiment of super-heavy element search, which leadto the synthesis of an atom of the element 113. Twothirds of the RRC research beam time is used for nuclear physics and nuclear astrophysics, and remaining
one third is used for atomic physics, material science,nuclear chemistry, radiation biology and others. The
AVF beam time was also used for ﬁelds other than
nuclear physics.
The RARF carries many international collaborations. Among them are two large-size collaboration
programs using overseas accelerator facilities: one is
the muon science project at ISIS in collaboration with

the Rutherford-Appleton Laboratory (RAL), and theother is the spin physics program at RHIC in collaboration with the Brookhaven National Laboratory (BNL).
The pulsed muon-beam facility at ISIS has been operating steadily. At the RHIC facility, with the new AGS
snake made by RIKEN, polarization of proton was improved to 40–50% and stabilized. The research grouphas succeeded to measure direct photon cross section,
asymmetry of which is the ﬁrst key to solve “spin crisis”. Other smaller collaborations using foreign facilities are underway at CERN (Switzerland/France)
and GSI (Germany). We have collaborated with the
CNS for operating the low-energy RI beam separator(CRIB) to use the low-energy beam from the AVF.
Several experiments of nuclear astrophysics and spectroscopy have been performed by using light RI beams
of a few A MeV available as a CNS/RIKEN facility.
Highlights of the year for the research at RARF
are as follows. (1) Besides the production of the isotope 278 113, production and decay of the 112th element 277 112 has been conﬁrmed. (2) In-beam γ
spectroscopy has been performed for light neutronrich nuclei, 15,17 B, 17,19 C, 23 O, and 23,27 F, excited byproton- and α-inelastic scattering, neutron removal reactions, and nucleon transfer reactions. Many newlevels have been identiﬁed, and measured transition
strengths have revealed new feature of nuclear structure, such as decoupling of neutron motion. (3) Reactions involved in stellar burning processes have beenstudied. Radiative capture processes for 18 Ne, 22 Mg
and 26 Si have been investigated by the Coulomb dissociation method. Several low-energy resonant statesin 21 Na, 22 Mg and 23 Mg have been found by the thicktarget method utilizing the low-energy RI beams fromthe CRIB. (4) The nuclear moment study has been
extended to the sd-shell region, and the magnetic moments for 23 Al, 30 Al and 32 Al have been determined.
(5) A precision measurement of Coulomb and nuclear
breakup of one of the one-nucleon halo nuclei 11 B has
been made, and the breakup mechanism has been clariﬁed in details. (6) A pilot device for a slow RI-beamfacility (SLOWRI) using an rf ion guide achieved aoverall eﬃciency of 5% for ≈100A MeV 8 Li from RIPS.
The ions were trapped in a linear rf trap for precision hyperﬁne structure spectroscopy. (7) The reaction cross section and fragment momentum distribution for 23 Al, a candidate of proton halo nuclei, havebeen measured. (8) The rf deﬂector improves the fraction of the beam of interest in the cocktail secondary
beams, and has been used for many experiments with
proton-rich beams. For example, the 0+ → 2+ transi-

1tion probabilities have been measured for the ﬁrst timeby Coulomb excitation for 46 Cr, 50 Fe and 54 Ni. (9) The
TOF spectrometer for precise particle identiﬁcation of
the reaction products of RI-beam induced reaction has
been completed. (10) It has been found that heavy-ion
irradiation enhanced the activity of DNA-PK, whichacts as a sensor of DNA double-strand breaks (DSBs)
during non-homologous end-joining, more than X-ray
irradiation. (11) New types of sterile mutants in ornamental ﬂowers such as self-incompatibility and antherdeﬁciency have been found by the plant-mutagenesis
using ion-beam irradiation.
Other related research activities are as follows. a)
An evidence of strongly bound kaonic system in K− ppn
with the total binding energy of 175 MeV has been obtained. b) A new scheme to store positrons realizedwith ≈30 times higher accumulation eﬃciency thanever realized under ultra-high vacuum condition. c)
Antiprotons trapped and cooled have been extracted
at 10–500 eV with high eﬃciency for the ﬁrst time. d)
New type of ion source was developed, which broke theworld record of carbon intensity by factor 100.
The RI beam factory project is in progress. Construction of the experimental facility building is about
to be completed. The fRC is being constructed for2completion by March in 2005. The assembling of thesector magnets and vacuum systems for the IRC has
been completed. The assembling of the sector magnets
and the superconducting coils of the SRC is in progress.
A part of the fragment separator Big RIPS has been installed, and test of super-conducting quadrupole magnets has been started. The ﬁrst production of RI
beams are foreseen in the year 2006.
For experimental installation of RIBF in its phaseII, various research and developments are being performed. For Self-Conﬁning Radioactive Ion Target(SCRIT), test experiments were carried out at KSR
of Kyoto University. A new scheme of mass measurements using an isochronous ring has been developed. Design of a large acceptance spectrometer (SAMURAI) and a high-resolution spectrometer(SHARAQ) have progressed. For creation of highlypolarized RI beams using primary beams from IRC
and the RIPS, a new system using the atomic beam
method is being developed.

T. Motobayashi
Director, Accelerator-based Research GroupRIKEN Accelerator Research Facility

RIKEN Accel. Prog. Rep. 38 (2005)

RILAC operation
E. Ikezawa, M. Kase, O. Kamigaito, T. Nakagawa, N. Sakamoto, H. Okuno, N. Inabe, M. Wakasugi,
N. Fukunishi, M. Kobayashi-Komiyama, M. Kidera, Y. Higurashi, H. Ryuto, S. Kohara, M. Fujimaki,
M. Nagase, T. Kageyama, S. Yokouchi, A. Yoneda, T. Aihara,∗ T. Ohki,∗ H. Yamauchi,∗ A. Uchiyama,∗
K. Oyamada,∗ R. Koyama,∗ A. Goto, and Y. Yano
Throughout this reporting period, RILAC has beenin steady operation and has supplied various ion beams
for various experiments. Table 1 shows the statistics
for RILAC operation from January 1 through December 31, 2004. Regular RILAC operation was discontinued from January through February, 2004, for modification works of the injection line and installation
works of the cooling system. Table 2 summarizes thenumber of days allotted to the search for the heaviest
elements, radiation chemistry, accelerator mass spectrometry, and other experiments.
Research experiments on the heaviest elements havebeen carried out with a gas-filled recoil isotope separator (GARIS) at the e3 beam line since 2002. In
this year, the experiments were carried out 30 days in
April, 9 days in May, 27 days in July, and 23 daysin December. More than 1 pµA of the 5 MeV/u 70 Zn
beam was supplied to the experiments. The total beamservice time for the experiments was 1770 hours. As aresult, a convincing candidate event for the isotope of
the 113th element was observed for the first time on

Table 1. Statistics for RILAC operation from January 1
through December 31, 2004.

July 23, 2004.
The percentage of beam time used by the RIKEN
Ring Cyclotron (RRC) was approximately 32% of thetotal. The 4 He, 58 Fe, 58 Ni, 70 Zn, 86 Kr, and 136 Xe ionsaccelerated by RILAC were injected into RRC.
Table 3 shows the statistics for the numbers of dayson which RILAC ion beams were delivered using the
RFQ linac with an 18 GHz ECR ion source. The ion
beams of 9 elements were used for the experiments andbeam acceleration tests.
We carried out the following machine improvements
during this reporting period.
(1) The beam transport line of the RFQ linac withthe 18 GHz ECR ion source (18 G-ECRIS) was
modified. A superconducting ECR ion source(SC-ECRIS) was installed in parallel with theexisting 18 G-ECRIS. Thus, the beam transportline of the Cockcroft-Walton injector with the
8 GHz ECR ion source (NEOMAFIOS), which
has been used for many years, was dismantled.
Figure 1 shows the layout of the beam transportline of the RFQ linac with two ECR ion sources.
(2) A new deionizer watercooling system was installed. The cooling capacity is 400 kW. Thissystem has been used for the 18 G-ECRIS andthe SC-ECRIS. In addition, five water pumps,
two cooling towers, a deionizer water system,
and a control circuit for the cooling system of
RILAC were replaced with new ones.
(3) To enable stable operation and easy maintenance, the final stage of the rf power amplifier
for the RFQ linac was improved.
(4) For the RIKEN RI beam factory project, the accelerator room of RILAC was divided into an ion

Table 2. Beam time allocated to diﬀerent research groups.
Table 3. Statistics for RILAC ion beams delivered using
RFQ linac with 18 GHz ECR ion source.

∗

SHI Accelerator Service, Ltd.

3

Fig. 1. Layout of beam transport line of RFQ linac with two ion sources (18 G-ECRIS and SC-ECRIS).
The boundary of the ion source area and the acceleration area is also shown. SD-101 and SD-103
denote the dismantled shield doors.

source area and an acceleration area using a partition. Thus, shield doors (SD-101 and SD-103)
in the ion source area were dismantled. Figure 1
shows the boundary of the ion source area andthe acceleration area.
We experienced the following machine problems during this reporting period.
(1) The RFQ linac had a big vacuum leak on a4

cooling pipe of the stem. The No.5 cavity had asmall vacuum leak on a air pressure pipe of theshorting plate. These leaky parts were soldered.
(2) A new water pump of the deionized water circuit
for RILAC had a terminal breakdown after justone month of operation. Two weeks of scheduled
beam time was cancelled owing the trouble.

RIKEN Accel. Prog. Rep. 38 (2005)

RRC and AVF operation
M. Kase, E. Ikezawa, T. Nakagawa, O. Kamigaito, H. Ryuto, N. Fukunishi, H. Okuno, N. Sakamoto,
M. Kidera, M. Wakasugi, N. Inabe, M. Kobayashi-Komiyama, T. Kageyama, M. Nagase, S. Kohara,
M. Fujimaki, A. Yoneda, S. Yokouchi, Y. Higurashi, Y. Ohshiro,∗1 N. Tsukiori,∗2 R. Ohta,∗2
K. Kobayashi,∗2 M. Nishida,∗2 Y. Kotaka,∗2 K. Masuda,∗2 S. Fukuzawa,∗2 T. Nakamura,∗2 ,A. Goto, and Y. Yano
Table 1 shows the statistics of the RRC and AVF
operation in 2004. Due to fund limitation for electric power in the ﬁscal year 2003, all the accelerators
stopped operation in January and February 2004. And
also unscheduled shutdown took place frequently during the second half of 2004 due to machine troubles.
Therefore the total operation hours per year was shortened by 15% than that in the previous year.
Table 2 shows the beam service time for each beamcourse of RARF from E1 to E7 as shown in Fig. 1.
About 80% of the total beam time was devoted toexperiments using secondary beams (RI beams) produced at RIPS by projectile fragmentations. For
the eﬃcient production of RI beams, intense primary

Table 1. Operation statistics of RRC and AVF in 2004.
Operation time of RRC
Beam service time
Machine trouble
Nuclear physics experimentNon-nuclear physics experiment
RILAC-RRC operation
AVF-RRC operation

5091
3421
736
78
22

(5678) hr(3739) hr(239) hr(74) %(26) %

2377(11) %(89) %

Operation time of AVF standalone
999(1582) hr
Beam service time637
(1192) hr
Figures in parentheses are data obtained in 2003.

Table 2. RRC and AVF beam time for each beam course
in 2004.
Target room
Total time (hr)No. of experiments
E1
0 (100)0 (6)E2134 (117)4 (3)E3182 (342)
8 (13)
E4 (SMART)
189 (538)6 (9)E5183 (286)
29 (40)E6 (RIPS)
2650 (2342)
27 (25)
RRC/D (MS)107
5
AVF (C03)§
192 (158)7 (5)E7 (CRIB)§
445 (1034)
9 (16)§
AVF stand-alone only, used for CNS of the Universityof Tokyo. Figures in parentheses are data obtained in
2003.
∗1
∗2

Center for Nuclear Study, University of Tokyo
SHI Accelerator Service, Ltd.

Fig. 1. Layout of beamlines of RRC and AVF.

beams of heavy neutron-rich isotopes are increasingly
required, such as 48 Ca, 58 Fe, and 86 Kr. The AVFRRC scheme supplies relatively low intensities for thesebeams (only several pnA). Since RRC operation witha harmonics of 8 was successfully carried out in 2002,
beams of these heavy particles have been accelerated
in the RILAC-CSM-RRC scheme. The data for thesebeams accumulated thus far are listed in Table 3. In allcases, beam intensity drastically increased; nevertheless the beam energy are somewhat lower (63 MeV/u)than those in the AVF-RRC scheme. Since a highbeam intensity sometimes overcomes the drawback of
a low beam energy in RI beam production, this new
scheme has been frequently used for recent RIPS experiments.
The upgrade of the AVF has been in progress in cooperation with CNS of the university of Tokyo. The
ﬂattop acceleration system was added to the AVF cavities in 2002. The power supplies will be improvedin order to increase the maximum energy of light ion
beam in the beginning of 2005. As results, the Kvalue of the AVF will be upgraded from 70 to 78 MeV.

5

Table 3. Upgrade of beam intensities with CSM.

The maximum energy of the nitrogen beam becomes
higher than 9 MeV/u and it extends the availability of
RI beams by the CRIB in E7.
The cogeneration system (CGS) can supply a powerof 6.5 MW at maximum, which is enough to cover the
power consumption of the existing accelerators. The
CGS operation, which had been carried out in theframework of accelerator operations, was handed overto the Facilities Maintenance Section of the RIKEN administration oﬃce at the beginning of Oct. 2004. The
heat source for air-conditioning in Nishina Memorialbuilding was switched to the absorption chiller in the
CGS in March 2004 instead of three sets of mechanicalchillers in order to save the power (300 kW).
A serious trouble was found in the #1 rf cavity of
RRC in June 2004. The contact ﬁngers of the upper
moving box (that is, one of the coarse tuners) weredamaged during the operation caused by a controlsequence problem. The scale of the damage was solarge that it took about two months to repair themcompletely. The experiments scheduled with the RRC
from the end of June to July were all cancelled. In
the mean time, superheavy-element research experiments were performed instead, leading to the discovery

6of Z = 113 element on 23 July.
As the RIBF project is approaching the commissioning in 2006, the RARF needs to start relevant preparations as follows: The production of uranium ions at
RILAC ion source will begin in summer 2005, and its
acceleration test will start in autumn 2005. In order torealize it, we applied an oﬃcial license of the uranium
acceleration to 11 MeV/u with the RRC in the end of
2004. The development of a charge stripper that canwithstand uranium beams is in progress.
Since the construction of the ﬁxed-frequency Ring
Cyclotron (fRC) will start in July 2005 in the E4 target
room (see Fig. 1), an experiment with the SMART
should come to an end in May 2005. Some magnets in
SMART will be transferred to the new building of the
RIBF experimental hall, and will be used there as partof a new apparatus. The extraction beamline of fRC
will be built in the D, RRC and E1 rooms as shownin Fig. 1 by thin lines. The operation of RRC will beinterrupted due to the construction of these beamlines
from April to June 2006. In autumn 2006, the RILAC
and RRC will begin to provide beams into the RIBF
accelerators (fRC, IRC and SRC).

RIKEN Accel. Prog. Rep. 38 (2005)

Cogeneration system operation
T. Fujinawa, E. Ikezawa, K. Yamaguchi, M. Kase, and Y. Yano
It has been passed twenty months since the Cogeneration system (CGS) was introduced in spring 2003.
During this period, the CGS has been in stable operation mainly for supplying electrical power to RARF
accelerators. The operation statistics in FY2003 and2004 is shown in Tables 1 and 2. At present, the CGS
operates only in the daytime during weekdays and Saturday because there is not yet a constant demand forthermal loads and because the low electricity charge
rate during the night is too low. This may cause theproblem that the current overall eﬃciency (42.5%) is
not as high as that expected in 2007, when the whole
facility will start to be operational. The CGS operates
primarily electricity generation since less there is demand for thermal load at present. The performance of
the CGS with a full refrigerator load in 2007 is shownin Table 3. The refrigerator load over 920USRT electrical output will decease from 6.5 MW, but overall efﬁciency will be better. The total refrigerator capacity
is 9.5 MW (2700USRTa) ) with ﬁve 1.4 MW (400USRT)
and two 1.2 MW (350USRT) absorption chillers (7◦ C).
The chilled water 670 kW (190USRT)) is used to cool
the compressor-inlet air in order to increase the hotweather capacity.
The reliability of turbine blades was improved toincrease the maximum electrical output from 6.3 to
6.5 MW in august 2004.（The unit price changed from=Y8.96/kW to =Y8.86/kW this makes =Y1000/h proﬁt &a heat recovery of =Y685.7/h.）
As an eﬀort to increase the head load to the CGS, itscooled water line was connected to those in the Nishina
memorial building and the linac buildings in the winterof 2004. In April 2004, some old chillers on these buildings stopped their operation, and the CGS commenced
to supply 7◦ C cooled water (3.7 t/min) to these buildings instead. It is used for the air-conditioning units

Table 2. Total cost.
Unit rate
Electrical output only
Inc heat recovery
Fixed cost
ProfitElectrical basic costGas unitrate down
Loss
Private generator charge by TEPCO
Operator cost
Consumable
Maintenance
Profit

=
Y/kWh
10.2
9.68
=
Y
184558500
27669966=
Y−38669400−36000000−7653023−38627556
91278487

Table 3. Performance of CGS expected in 2007.
Electric output at 15◦ C
Steam production
Electrical eﬃciency
Overall eﬃciency
Refrigeration capacity
NOx emission

5,790 kW
10,300 kg/hr
32.1%
64.4%
2510USRT
32.3 ppm

in the rooms of beam lines, experimental apparatus,and power supplies as well as accelerators, i.e., RRC,
AVF, and RILAC. It is also supplied to the heat exchanger of the vacuum cooling system in order to lower
the temperature of water for compressors of cryogenic
vacuum pumps of RRC and AVF with these improvements, approximately 300 kW of electric power can besaved.
CGS operation and maintenance have been carriedout in the framework of accelerator operations. In October 2004, according to the RIKEN policy that energy aﬀairs should be managed by one division, the
CGS operation and maintenance was handed over tothe Facilities Maintenance division.

Table 1. Statistics of CGS operation from April, 2003 to end of September, 2004.

Operation time
Scheduled shutdown
Overhaul and improvement
Sum
Direct cost

2003
No.of Days
270
69
34
373

%
72.4
18.5
9.1
100

2004
No.of Days
153
29
1
183

%
83.6
15.8
0.6
100

=
Y
kWh
=
Y
kWh
207602218 19938240
138433342 13999075
10.41 (Y=/kWh)
9.89 (Y=/kWh)
3
=
Y
Nm
=
Y
Nm3
Used gas of CGS
196194230
5510220150541736
4023150§
50.8% and 16.5% of total consumption in RARF and RIKEN, respectively.
Electrical output power

a)

Total
No.of Days
423
98
35
556

%
76.1
17.6
6.3
100

=
Y
kWh
346035560 33937315§
10.2 (Y=/kWh)=
Y
Nm3
346735966
9533370

United States Refrigeration Tom, 1USRT = 3.52 kW

7

RIKEN Accel. Prog. Rep. 38 (2005)

Operation of the tandem accelerator
T. Kobayashi and K. Ogiwara
The 1.7 MV tandem accelerator (Pelletron) was operated for a total of 93 days for experiments during theannual reporting period from Nov. 1, 2003 to Oct. 31,
2004. A total of 44 days was spent for machine inspection and beam test. The accelerated ion species in thisperiod are H+ , He+ and B+ with energies from 2.0 to
2.3 MeV.
Experimental studies on the following subjects were
performed, and are still in progress.
(1) Nuclear reaction analysis (NRA) using1
H(11 B, α)2α reaction (47 days)(a) The state of hydrogen in Nb-based and Tabased alloys as investigated by the channelingmethod(b) Eﬀect of irradiation on the state of hydrogenin metals(2) Particle-induced X-ray emission (PIXE)

8(28 days)(a) Development of a highly sensitive highresolution in-air PIXE system for chemical
state analysis(b) Trace element analysis of biological and environmental samples using energy dispersive
X-ray spectrometry(3) The analysis using elastic scattering (18 days)(a) Rutherford backscattering spectrometry (RBS)
analysis of polymers and carbon materials
containing metallic nanoparticles.
(b) Elastic recoil detection (ERD) analysis of
diamond-like carbon (DLC) thin ﬁlms andion-implanted polymers for determining hydrogen contents.
The total time in days, which was spent for eachexperiment, is shown in parentheses.

RIKEN Accel. Prog. Rep. 38 (2005)

Decay modes of heavy and superheavy nuclei
H. Koura∗[Decay by proton emission, Spontaneous ﬁssion, Binding energies and masses]
In the heavy and superheavy nuclidic region, somedecay modes coexist, such as α-decay, β-decay, andspontaneous ﬁssion. We have studied the estimationof partial half-lives of these decay modes1) with theuse of some decay models and the KUTY mass formula,2,3) and discussed the most probable decay modes
for each nucleus in that region. In addition to these
decay modes, proton emission is also a possible decay mode outer from a proton-drip line in that region.
In this report, we estimate proton-emission half-lives
with the use of a single-proton potential. We take themodiﬁed Woods-Saxon potential4) which is used for
calculating the KUTY mass formula. The central andspin-orbit parts are expressed as

Fig. 1. Experimental and calculated log10 (Tp1/2 /(s)).

1

Vcen (r) = V0

{1 + exp [(r − Rv )/av ]}av /κ
1
× 1 + Vdp
, (1)1 + exp [−(r − Rv )/av ]

and
1 1
2m
r

1
d
×
l • s,
dr 1 + exp [(r − Rls )/als ](2)

Vls (r)l • s = Vls0

where included parameters are taken to be smoothfunctions of Z and N , and the charge symmetry is
imposed on these potentials. This potential reproduces fairly well the experimental single-particle levelsof 15 doubly magic and magic-submagic nuclides in awide nuclidic region. The proton-emission partial halflives Tp1/2 are calculated by the one-dimensional WKB
method for this potential, including the central part,the spin-orbit part, and the Coulomb part. The spinparity and centrifugal force for a single proton are estimated from this potential. Figure 1 shows some experimentally measured, and calculated log10 (Tp1/2 /(s)) results for odd-Z nuclei. The diﬀerences between experimental Tp1/2 and calculated ones are nearly within 2
in log10 .
With the above calculation, we estimate the shortest partial half-lives among proton emission, α-decay,β-decay and spontaneous ﬁssion in the heavy and superheavy nuclidic region. To calculate the half-lives,
we take Q-values of the KUTY mass formula. Figure 2
shows the most dominant decay modes for the nuclei
with total half lives Ttotal1/2 > 10−9 s. In this ﬁgure∗

Fig. 2. Shortest partial half-lives among α-decay, β-decay,
spontaneous fission and proton emission. The Q valuesof KUTY’s formula are used for calculations of α-decay,β-decay and proton emission. The known nuclei are also
shown.5)

we can see some proton-emitting nuclei with N  100
near the proton-drip line. This tendency is roughly
similar to that of some experimental results. In theregion of 100  N  110 and 120  N  130, proton
emission is expected to be dominant, although these
nuclei are far from known nuclei. On the other hand,in the region of 110  N  120 and 130  N  160,
proton-emitting nuclei are not expected, because these
spontaneous ﬁssion half-lives seem to be very short, orless than 10−9 s in this region.
References
1) H. Koura: RIKEN Accel. Prog. Rep. 37, 11 (2004).
2) H. Koura et al.: Nucl. Phys. A 674, 44 (2000).
3) H. Koura et al.: RIKEN Accel. Prog. Rep. 36, 9 (2003).
4) H. Koura et al.: Nucl. Phys. A 671, 96 (2000).
5) T. Horiguchi et al.: Chart of the Nuclides 2000, Japan
Atomic Energy Research Institute (2001).

Advanced Science Research Center, Japan Atomic Energy
Research Institute9

RIKEN Accel. Prog. Rep. 38 (2005)

Variational calculations of nuclear equation of state
M. Takano∗[NUCLEAR STRUCTURE, Nuclear matter]
Recently, studies of the equation of state (EOS) for
asymmetric nuclear matter (ANM) have become important. For example, Oyamatsu and Iida1) pointed
out that future measurements of the radii of neutronrich unstable nuclei will provide some constraints for
the EOS of ANM, particularly for the proton-fraction
dependence of the saturation density ρ0 .
As one of the most powerful many-body techniques
for the theoretical derivation of the nuclear EOS, thevariational method such as the Fermi Hypernetted
Chain (FHNC) calculation, has been applied to symmetric nuclear matter (SNM) and pure neutron matter(PNM). However, in the case of ANM, there are only
few examples of the variational calculations2) because
the FHNC method is complicated.
In this study, we apply a new variational method,which we proposed in Ref. 3, for calculating the EOS
of ANM. The main feature of this method is to construct an approximate energy expression (AEE) which
expresses the energy per particle E/N as an explicit
functional of variational functions. Here, spin-isospindependent, central-, tensor- and spin-orbit-type twobody distribution functions are introduced as the variational functions. Since the three states of the isospintriplet have to be treated independently in the case of
ANM, there are 16 variational functions.
Spin-isospin-dependent structure functions, which
are the Fourier transforms of the central-type twobody distribution functions, are also introduced for
the AEE. There are several necessary conditions on
the structure functions, and the AEE automaticallyguarantees those necessary conditions.
Once the explicit AEE is constructed, the EulerLagrange equations for the variational functions arederived, and fully minimized values of E/N are obtained by solving them numerically.
This variational method has been applied to liquid3
He and fairly reasonable results have been obtained.
In the case of nuclear matter, however, a “phenomenological refinement” is necessary, i.e., the long-range
part of the noncentral nuclear forces such as the tensor and the spin-orbit components must be multiplied
by a damping function; without this refinement, thevariational calculation gives extremely low values for
E/N .4) The damping function has an adjustable parameter, the value of which is determined so that thecalculated saturation point for SNM becomes close to
the empirical one.
∗

10

Advanced Research Institute for Science and Engineering,
Waseda University

In order to construct the AEE for ANM, which ispartially isospin-polarized nuclear matter, we need toextend the formulation. This extension, from SNM
and PNM4) to ANM, is similar to the one carried out
in Ref. 5, where the AEEs for spin-unpolarized andfully spin-polarized liquid 3 He have been extended tothat for the partially spin-polarized one.
In Fig. 1, E/N for ANM calculated by this variational method with the AV18 potential is shown as
a function of the proton fraction ξ. Owing to the“phenomenological refinement”, E/N = −15.2 MeV
at ρ0 = 0.21 fm−3 is obtained for SNM. The resultfor ρ0 is somewhat high, which may be understandable
because the three-body nuclear force is not included in
the calculations.
In order to discuss the EOS of ANM in detail, better
reproduction of the empirical saturation point for SNM
is necessary.

Fig. 1. Energies per nucleon for ANM with the AV18 potential.

References
1) K. Oyamatsu and K. Iida: Prog. Theor. Phys. 109, 631(2003).
2) I. E. Lagaris and V. R. Pandharipande: Nucl. Phys. A
369, 470 (1981).
3) M. Takano and M. Yamada: Prog. Theor. Phys. 91,
1149 (1994).
4) M. Takano and M. Yamada: Prog. Theor. Phys. 100,745 (1998).
5) M. Takano, T. Endo, R. Kimura, and M. Yamada: Prog.
Theor. Phys. 109, 213 (2003).

RIKEN Accel. Prog. Rep. 38 (2005)

Importance of prolate neutrino radiationin core-collapse supernovae
H. Madokoro, T. Shimizu, and Y. Motizuki[shock waves, hydrodynamics, stars:neutron, supernova:general]
We study the eﬀects of the prolate and oblate neutrino heating on the mechanism of core-collapse supernovae. It is expected that neutrino radiation becomes anisotropic when a proto-neutron star rotates
and when convection occurs inside the proto-neutronstar. Our purpose in this study, which follows thatof previous studies,1,2) is to understand what kind ofneutrino radiation is favorable for a successful explosion through a parameter study when the total neutrino luminosity is given. The details of our results areshown in Ref. 3.
We performed 2D simulations by solving hydrodynamical equations in spherical coordinates (r, θ).1–3)
The local neutrino
ﬂux density is assumed to belν (r, θ) ∝ Tν4 1 + c2 cos2 θ /r 2 , where Tν is the neutrino temperature (we ﬁx Tν = 4.70 MeV in thisstudy), and c2 is a parameter which represents the degree of anisotropy in the neutrino radiation. The ratioof neutrino ﬂux along the polar axis (lz ≡ lν (r, θ = 0◦ ))and that on the equatorial plane (lx ≡ lν (r, θ = 90◦ ))becomes lz /lx = 1 + c2 . The models that we examined
are summarized in Table 1.
We have found that the eﬀect of anisotropy becomes
more powerful in both the prolate and oblate models
as the degree of anisotropy in the neutrino radiation
increases: the larger is the degree of anisotropy, thelarger is the explosion energy. It was found, however,that this eﬀect saturates at around a certain degree ofanisotropy. We found that, at a later stage of evolution, model pro100 (t < 360 ms) or pro150 (t > 360 ms)
shows the largest explosion energy among the prolate
models, while the explosion energy of model obl167

becomes the largest among the oblate models. Thismeans that the saturation of the eﬀect of anisotropic
neutrino radiation appears at lz /lx ∼ 1.1 − 1.15 for a
prolate explosion and lx /lz ∼ 1.2 for an oblate explosion. We also conﬁrmed that the explosion energy inthe prolate model of lz /lx = 1.1 is larger than thatin the saturated oblate model of lx /lz = 1.2. This is
explicitly illustrated in Fig. 1. In other words, the prolate explosion of lz /lx = 1.1 (which corresponds to ananisotropy of ∼ 5%) is always more energetic than any
other oblate models, even if the degree of anisotropy
in the neutrino radiation becomes larger. Combinedwith our previous results,1,2) we conclude that globally
anisotropic (prolate) neutrino radiation is the most effective way to increase the explosion energy among thevarious types of explosions investigated in these studies when the total neutrino luminosity is given. Our
results are suggestive of the observation that the expanding materials of SN1987A have been observed to
be deformed in a prolate form.

Table 1. Simulated models.
Model
sph000pro050pro100
pro150pro200pro250pro300obl048obl091
obl130obl167obl200obl231lz /lx
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1/1.05
1/1.101/1.15
1/1.201/1.25
1/1.30

c2
0.000
0.050
0.100
0.150
0.200
0.250
0.300
−0.048−0.091−0.130−0.167−0.200−0.231

Fig. 1. Evolution of explosion energy for saturated models: pro100 (solid line), pro150 (dot-dashed line), obl167(dashed line), and sph000 (dotted line).

References
1) T. M. Shimizu et al.: Astrophys. J. 552, 756 (2001).
2) H. Madokoro, T. Shimizu, and Y. Motizuki: Astrophys.
J. 592, 1035 (2003).
3) H. Madokoro, T. Shimizu, and Y. Motizuki: Pub. Astron. Soc. Jpn. 56, 663 (2004).

11

RIKEN Accel. Prog. Rep. 38 (2005)

Study of supernova explosions with neutrino-transfer hydrodynamics
K. Sumiyoshi,∗1 H. Suzuki,∗2 S. Yamada,∗3 and H. Toki∗4[supernova, EOS, neutrino]
Understanding the explosion mechanism of corecollapse supernovae is a challenging problem, that requires extensive researches in nuclear physics and astrophysics. In order to reach the ﬁnal answer, it isnecessary to investigate the core-collapse supernovae
by implementing hydrodynamics and neutrino-transfer
together with reliable nuclear equation of states andneutrino-related reactions. Advances in physics of unstable nuclei in radioactive nuclear beam facilities havegiven chances to provide us with nuclear physics in supernovae than ever before, hence, new nuclear data
supported by extensive experiments should be examined in modern supernova simulations.
We study the explosion mechanism of collapsedriven supernovae by numerical simulations with a new
nuclear equation of state (EOS) based on unstable nuclei. We especially focus on the inﬂuence of the new
nuclear EOS in the neutrino-transfer hydrodynamics.
We follow the core-collapse, bounce and shock propagation by adopting the new EOS, which is based on
the data of unstable nuclei, and the conventional one
which has been used almost uniquely in recent simulations. We compare the behavior of shock and thethermal evolution of supernova core by performing numerical simulations for a long period of ∼1 sec after
the core bounce.
A new complete set of EOS for supernova simulations (Shen’s EOS) has become available1,2) by the
relativistic mean ﬁeld (RMF) theory with a local density approximation. The RMF framework with the parameter set TM1 has been successful to reproduce theproperties of ﬁnite nuclei including n-rich ones.3) For
comparison, we adopt also the EOS by Lattimer andSwesty.4) The EOS is based on the compressible liquid
drop model for nuclei together with dripped nucleons.
We have developed a new numerical code ofneutrino-transfer hydrodynamics5,6) for supernova
simulations. The code solves hydrodynamics andneutrino-transfer at once in general relativity under
the spherical symmetry. As an initial model, we adopt
the proﬁle of iron core of a 15 M massive star. We
perform the numerical simulations with Shen’s EOS(denoted by SH) and Lattimer-Swesty EOS (LS) forcomparisons.
It is remarkable that the explosion does not occur inthe model SH, i.e. the case with the new EOS table,
and the shock wave stalls in a similar manner as the
∗1
∗2
∗3
∗4

12

Numazu College of Technology
Faculty of Science and Technology, Tokyo University of Science
Science and Engineering, Waseda University
Research Center for Nuclear Physics, Osaka University

model LS. The shock in SH does not reach at a signiﬁcantly larger radius than in LS (Fig. 1). The shockstalls below 200 km and starts receding in two cases.
We have found, however, that there are quantitative
diﬀerences in core-collapse and bounce due to the differences between nuclear EOSs.7) Having a larger symmetry energy in SH, free-proton fractions during collapse in SH are smaller than in LS. Smaller free-proton
fractions lead to smaller electron capture rates if electron captures on nuclei are suppressed. The diﬀerenceof EOS becomes apparent having a more compact starfor LS with the central density of 6.6 × 1014 g/cm3(4.0 × 1014 g/cm3 for SH) at 800 ms after the bounce.
The peak structure of temperature at around 10 km isformed and the peak temperature reaches at 38 and
51 MeV for SH and LS, respectively, due to the gradual compression of core having accretion. These diﬀerences of thermal structure may give inﬂuences on shock
dynamics, supernova neutrinos and proto-neutron starcooling. Further details of the full numerical simulations will be published elsewhere.6)

Fig. 1. Radial trajectories of mass elements of the core of
15 M star as a function of time after the bounce (SH).

References
1) H. Shen, H. Toki, K. Oyamatsu, and K. Sumiyoshi:
Nucl. Phys. A 637, 435 (1998).
2) H. Shen, H. Toki, K. Oyamatsu, and K. Sumiyoshi:
Prog. Theor. Phys. 100, 1013 (1998).
3) Y. Sugahara and H. Toki: Nucl. Phys. A 579, 557(1994).
4) J. M. Lattimer and F.D. Swesty: Nucl. Phys. A 535,
331 (1991).
5) K. Sumiyoshi, S. Yamada, H. Suzuki, H. Shen, and H.
Toki: Nucl. Phys. (2005), in press.
6) K. Sumiyoshi, S. Yamada, H. Suzuki, H. Shen, S. Chiba,
and H. Toki: Submitted to Astrophys. J. (2005).
7) K. Sumiyoshi, H. Suzuki, S. Yamada, and H. Toki:
Nucl. Phys. A 730, 227 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Neutron star matter in a chiral quark theory†
S. Lawley,∗1 W. Bentz,∗2 and A. W. Thomas∗3[MATTER AT HIGH DENSITY, Neutron matter]
Many ideas in the area of ﬁnite density phase transitions have been developed in the context of neutronstar calculations, in particular the phase transitions
from nuclear matter (NM) to quark matter (QM).1) In
this work we calculate both the NM and QM phasesin β-equilibrium using the ﬂavor SU(2) ﬂavor Nambu–
Jona-Lasinio (NJL) model. Recently, the problem of
NM saturation has been addressed with a method tosimulate conﬁnement in the description of the nucleon
as a quark-diquark bound state.2) In the QM phase, weallow for the possibility of scalar diquark condensation(color superconductivity),3) and the mixed phases arecalculated using the method of Glendenning.1)
The eﬀective potential for NM is V N M = Vvac +VN −Vω − Vρ − Ve , where the vacuum term Vvac accounts forthe polarization of the quark Dirac sea due to the valence nucleons,2) VN represents the Fermi motion of thenucleons which are described as quark-diquark boundstates, Vω and Vρ are contributions from the isoscalarand isovector mean vector ﬁelds respectively, and Ve is
the electron contribution which is necessary for chemical equilibrium.
The eﬀective potential for QM is V QM = Vvac +VQ − Ve + V∆ , where the vacuum and electron terms
are as above and the term for the Fermi motion of thequarks VQ is analogous to VN , but refering to up anddown quarks instead of protons and neutrons. Color
superconducting quark matter (SQM) includes a contribution from the quark pairing arising at the Fermi
surface. This is expressed by the term V∆ , which involves the pairing gap ∆ and a coupling constant (Gs )for the pairing interaction in the scalar diquark channel.
In the calculations we set the constituent quark mass
to zero, as it is known to decrease rapidly with density.3) The strength of the pairing interaction is set
to GS = 0.25Gπ , where the coupling constant in thepionic channel (Gπ ) is ﬁxed by reproducing the pionmass. To construct the phase diagram we compare the
NM and QM eﬀective potentials for each baryon andisospin chemical potential µB and µI , respectively.
Figure 1 shows the phases in the plane of the chemical potentials. The charge neutral equation of state
trace the lines between the positively and negatively
charged regions. It begins in the NM region, proceeds
along the boundary between negatively charged NM
†
∗1
∗2
∗3

Condensed from an article by S. Lawley, W. Bentz, andA. W. Thomas, to be published.
Department of Physics, University of Adelaide, Australia
Department of Physics, Tokai University
Jeﬀerson Laboratory, USA

Fig. 1. Phase diagram in the plane of chemical potentials
for baryon number and isospin.

and positively charged SQM, and ends in the SQM
phase. The boundary between the NM(–) phase andthe SQM(+) phase, which is rather short in this case,corresponds to the NM/SQM mixed phase. The volume fractions of NM and SQM in the mixed phaseare obtained by the requirement of charge neutrality.
It is important to observe that the coupling constantGs = 0.25Gπ is suﬃciently strong to support a superconducting gap which is stable for isospin asymmetricmatter. Figure 2 shows the phases in the plane of thecharge density ρC and the baryon density ρB . We seethat charge neutral matter will have a pure NM phasein the lower density region and a pure SQM phase athigh densities. Between there is a mixed phase at intermediate densities.

Fig. 2. Phase diagram in the plane of charge and baryon
density.

References
1) N. K. Glendenning: Compact Stars (Springer, New
York, 2000).
2) W. Bentz and A. W. Thomas: Nucl. Phys. A 696, 138(2001).
3) W. Bentz, T. Horikawa, N. Ishii, and A. W. Thomas:
Nucl. Phys. A 720, 95 (2003).

13

RIKEN Accel. Prog. Rep. 38 (2005)

Linear response theory in the continuum for deformed nuclei:
Green’s function vs absorbing-boundary condition†
T. Nakatsukasa∗ and K. Yabana∗[NUCLEAR STRUCTURE, Unstable nuclei]
The time-dependent Hartree-Fock (TDHF) theory
is a dynamical theory and takes both collective andsingle-particle excitations into account. Its smallamplitude regime is known as the random-phase approximation (RPA) for eﬀective density-dependent
forces. The spreading width, which is partially described in the TDHF theory (one-body dissipation), is
known to be important in broadening giant resonances.
However, for light nuclei, the escape width is the dominant factor and becomes even more important near the
drip line. In this paper, we propose a feasible methodof treating the continuum in real-space TDHF calculation, that is, the absorbing-boundary condition (ABC)approach. We studied photoabsorption in molecules1)
and nuclear breakup reaction2,3) using a similar technique.
The method, we call TDHF+ABC, is suﬃciently
simple and accurate for calculating nuclear responses
in the continuum for spherical and deformed nuclei. Its
small amplitude limit is equivalent to the continuum
RPA.4) Its advantage over the continuum RPA is its
applicability to nonspherical systems. In addition, theTDHF wave function in the coordinate space provides
us with an intuitive picture of the nuclear collective
motion and the damping mechanism of the escape ofparticles. The time evolution of the TDHF states iscalculated using the predictor-corrector method.5) A
technique of treating the continuum is the introductionof an absorbing complex potential outside interaction
region. The potential must be properly chosen so as
to achieve minimum reﬂection.
We study E1 responses in neutron-rich Be isotopes.
The full Skyrme functional (SIII) is used in the calculation. A perturbative external ﬁeld is chosen as
Vext (r) = e1 r 1 Y10 , where e1 is the E1 recoil charge.
The time evolution is determined using the TDHF
equation with the complex absorbing potential −iη(r)ih̄∂
ψi (r, t) =∂t{h[ρ(t)] + Vext (r)δ(t) − iη(r)} ψi (r, t),∗

14

Table 1. Energy-weighted sum rule in units of e2 fm2 MeV.
S(E1)class indicates the classical TRK value. S(E1)
is obtained using the present TDHF+ABC method.
S̃(E1) gives the soft E1 strength.

8

Be
Be
12
Be
14
Be
10

S(E1)class

S(E1)S̃(E1)

29.7
35.7
39.6
42.5

34.0
42.8
48.2
52.2

3.14
1.26
2.54
7.57

References(1)

where i = 1, · · · , A and  is a small parameter for validating the linear response approximation. η(r) is zeroin the physically relevant region of space. The TDHF
equation, Eq. (1), is solved in real time from t = 0 to
30 h̄/MeV, and then we perform the Fourier transform.
†

The single-particle wave functions are represented inthree-dimensional coordinate space. A nonuniform
adaptive mesh is adopted in the calculation. See ouroriginal paper for details.
The calculated energy-weighted sum rule values arelisted in Table 1. The soft E1 strength, S̃(E1), is deﬁned by integrating the E1 strength in the continuum,dB(E1)/dE, from E = 0 to 15 MeV. The enhancementof the soft dipole strength is signiﬁcant for 14 Be. The
large S̃(E1) value for 8 Be is due to a large deformation
splitting of the giant dipole resonance. For 12 Be, we
obtain the ground state with a small prolate deformation. The lowest dipole state appears near the threshold, at E ≈ 4.5 MeV, with B(E1; 0+ → 1− ) = 0.023 e2
fm2 . The corresponding experimental data6) indicate
E = 2.68 MeV with B(E1) = 0.051(13) e2 fm2 .
For 14 Be, the calculated ground state has a superdeformed prolate shape (β ≈ 0.75). The lowenergy dipole state is embedded in the continuum at
E ≈ 5 MeV with a signiﬁcant E1 strength, B(E1) ≈0.26 e2 fm2 . The peak position is almost at the sameenergy as that for 12 Be, however, the strength is about
10 times larger. The experiment results seem to indicate a certain enhancement of the Coulomb dissociation cross section at approximately E ≈ 2 and≈ 5 MeV.7)

Condensed from the article submitted to Phys. Rev. C 71,
024301 (2005).
Center for Computational Sciences, University of Tsukuba

1) T. Nakatsukasa and K. Yabana: J. Chem. Phys. 114,
2550 (2001).
2) M. Ueda, K. Yabana, and T. Nakatsukasa: Phys. Rev.
C 67, 014606 (2002).
3) M. Ueda, K. Yabana, and T. Nakatsukasa: Nucl. Phys.
A 738, 288 (2004).
4) S. Shlomo and G. F. Bertsch: Nucl. Phys. A 243, 507(1975).
5) H. Flocard, S. E. Koonin, and M. S. Weiss: Phys. Rev.
C 17, 1682 (1978).
6) H. Iwasaki et al.: Phys. Lett. B 491, 8 (2000).
7) M. Labiche et al.: Phys. Rev. Lett. 86, 600 (2001).

RIKEN Accel. Prog. Rep. 38 (2005)

Molecular structures of excited 10 Be and nucleon transfer
in α + 6 He scattering
M. Ito,∗1 K. Yabana,∗1 K. Katō,∗2 and K. Ikeda[NUCLEAR STRUCTURE, cluster model, unstable nuclei]
In studies on light neutron-rich nuclei, much attention has been concentrated on couplings between
the clusters and the motion of the valence neutrons.
From the viewpoint of these couplings, Be isotopes(= α + α + n + n . . .) have very interesting features.
In this system, the low-lying states can be understoodin terms of molecular orbitals, as they are a singleparticle motion around two α-cores,1) while the “Hemolecules” such as 12 Be = 6 He + 6 He are observed in
the excited states.2,3) These mean that exotic structural change occurs between the “molecular orbitals”
and the “valence bonds” in this system.
In order to understand this exotic structural change,
we proposed a “generalized two-center cluster model”(GTCM) and applied the model to the 10 Be = α + α +2n system.4) In this model, the total wave function isexpressed by a linear combination of the “atomic orbitals” having (α + n) + (α + n) and α + (α + 2n)
structures. The α particle is described by the (0s)4
conﬁguration in the harmonic oscillator (HO) potential
and the valence neutrons are speciﬁed by the atomic
orbitals in which the neutrons are localized at one ofthe α cores with 0pi orbitals (i = x, y, z) in the same
HO. The constructed atomic-orbital states are fully
antisymmetrized and projected to the eigenstates of
the total spin and the parity. This model naturally describes the molecular orbitals at a small α-α distanceas well as the asymptotic cluster states of α + 6 He
and 5 He + 5 He at a large α-α distance. To describe
the resonance boundary conditions, we also apply themethod of the absorbing kernels in generator coordinates (AGC) on GTCM, which is a revised version of
the complex absorbing potential (CAP) method for application to the microscopic cluster model.
The calculated energy surfaces and the energy spectrum are shown in Fig. 1. We obtained two boundstates around the respective local minimum in the energy surfaces, which have molecular orbital conﬁgurations consistent with those in previous studies.1) Furthermore, we have found two resonant states above theα + 6 Heg.s. threshold. The 0+
3 state has a large com+ponent of the α + 6 He(2+1 ) channel, while the 04 stateis the molecular-orbital state with the conﬁguration of− 2) . We also solve the scattering problem in this
(π1/2
system and ﬁnd a pronounced peak in the scatteringmatrix (S-matrix) of the transition from α + 6 Heg.s. to∗1∗2

Institute of Physics, University of Tsukuba
Division of Physics, Graduate School of Science, Hokkaido
University

Fig. 1. Adiabatic energy surfaces (white circles) and the energy spectrum (horizontal bars) in 10 Be (J π = 0+ ). The
lowest and second-lowest states are the bound states−
having the molecular orbital configurations of (π3/2)2+2and (σ1/2 ) , respectively, while the highest state has a−)2 . In the right part of the figure,configuration of (π1/2
the magnitude of the scattering matrix is also shown.

α + 6 He(2+1 ).
The strong enhancement of the S-matrix can be seen,
and its position is coincident to the resonance energyof 0+
3 , which reﬂects the large population of the ﬁnal
channel in the resonant state. Conversely, the strengthof the S-matrix corresponding to the 0+
4 state is weak,because it has a molecular orbital conﬁguration thathas a diﬀerent structure from the incident channel (α+6Heg.s. ) and the exit one (α+ 6 He(2+1 )). Therefore, theexcitation of the resonant states has a close connection
to their intrinsic structure. For Be isotopes, uniﬁed
studies on their nuclear structure and nuclear reaction
are now in progress.
References
1) N. Itagaki and S. Okabe: Phys. Rev. C 61, 044306(2000).
2) M. Freer et al.: Phys. Rev. C 63, 034301 (2001).
3) A. Saito et al.: Prog. Theor. Phys. Suppl. No. 146, 615(2002).
4) M. Ito, K. Kato, and K. Ikeda: Phys. Lett. B 588, 43(2004).

15

RIKEN Accel. Prog. Rep. 38 (2005)

Fusion reaction of halo nuclei†
M. Ito,∗1 M. Kobayashi,∗1 K. Yabana,∗2 T. Nakatsukasa,∗2 and M. Ueda∗3[NUCLEAR REACTION, Unstable nuclei]
Since the discovery of the halo structure in radioactive beam experiments, much eﬀort has been devoted to developing reaction theories appropriate forhalo nuclei and to elucidating their reaction mechanisms. At medium and high incident energies, such
as E > 50 MeV/A, the eikonal theory has been successful in describing the reaction. On the other hand,at low incident energies, E < 50 MeV/A, the fundamental mechanism of the reaction has not been fully
elucidated thus far.
Halo nuclei consist of the core nucleus and a few
halo nucleons, which are bound weakly in the projectile. At high energies, the eikonal theory suggests thatthe core and the halo nucleons are independently scattered by the target nucleus. The interaction between
the core and the halo nucleons plays only a minor role
during the reaction. We will show that the independent scattering picture also holds for the reactions at
low incident energies.
To elucidate the reaction mechanism of the halo nuclei at low incident energies, we have been developing atime-dependent wave-packet approach using the threebody reaction model.1,2) We have shown that the fusion probability is suppressed by the presence of theneutron halo. In this paper, we present our extended
analyses for both neutron and proton halo cases. The
fusion probability is suppressed by the neutron halo
and is enhanced by the proton halo. The reason forthese opposite eﬀects of the halo nucleons on the fusion probability is related to the spectator role of the
weakly bound nucleon. This analysis provides a uniﬁed
picture for the reaction mechanism of halo nuclei.
We adopt a three-body model; a halo nucleon (n)and a core nucleus (C) constitute the projectile (P) colliding with a target nucleus (T). The method is basedon the time-dependent Schrödinger equation

collision, then calculate the time evolution in the coordinate space. The fusion is identiﬁed as the ﬂux loss
due to the imaginary part of the core-target potential,
VCT (RCT ). The energy projection before and after thetime evolution gives the fusion probability as a function of energy. In Fig. 1, we show the calculated fusion
probability for a neutron halo nucleus, 11 Be = 10 Be+n,
and a hypothetical proton halo nucleus, 11 Be = 10 Li+p(a weakly-bound s-wave proton is assumed). The target is assumed to be 208 Pb. The result clearly indicates the suppression of the fusion cross section for theneutron halo case and the enhancement of it for the
proton halo case, compared with the one without thehalo nucleon.
The time evolution of the calculated wave packet
suggests a spectator role in the dynamics of the weaklybound nucleon. For the neutron halo case, the core
nucleus is scattered in the backward direction by the
Coulomb repulsion between the core and the target nuclei. This leads to the Coulomb breakup of the halo
neutron. Since the neutron carries approximately 10%of the incident energy, the core eﬀectively loses its energy (10 Be), which results in the suppression of fusion.
Conversely, in the case of the proton halo projectile,
the halo proton is scattered in the backward direction
by the target Coulomb ﬁeld, which is much stronger
than the core nucleus is. This leads to the backward
proton breakup, then the charge of the projectile decreases from Z to Z − 1, which increases the fusion
probability.


h̄2
h̄2 2
− ∇2R −∇
2µ2m r
+ VnC (r) + VCT (RCT ) + VnT (rnT ) Ψ(R, r, t), (1)ih̄∂
Ψ(R, r, t) =∂twhere we denote the relative n-C coordinate as r andthe relative P-T coordinate as R. The reduced massesof n-C and P-T motions are m and µ, respectively.
We prepare an initial wave packet boosted toward theFig. 1. Fusion probability as a function of incident energy.
The ‘2-body’ indicates the fusion probability between
the core and the target nuclei without a halo nucleon.

†

References

∗1
∗2
∗3

16

Condensed from articles in Nucl. Phys. A 738, 303 (2004);
Prog. Theor. Phys. Suppl. No. 154, 85 (2004).
Institute of Physics, University of Tsukuba
Center for Computational Sciences, University of Tsukuba
Akita National College of Technology

1) K. Yabana: Prog. Theor. Phys. 97, 437 (1997).
2) K. Yabana, M. Ueda, and T. Nakatsukasa: Nucl. Phys.
A 722, 261c (2003).

RIKEN Accel. Prog. Rep. 38 (2005)

Microscopic study of 16 C + 208 Pb inelastic scattering
M. Takashina, Y. Kanada-En’yo,∗1 and Y. Sakuragi∗2[NUCLEAR REACTION, Unstable nuclei]
Recently, the opposite deformations between protonand neutron densities in C isotopes were theoreticallysuggested1) by the method of antisymmetrized molecular dynamics (AMD). The author also gives a qualitative explanation2) for the unusually small B(E2; 2+
1 →
2
4
16
0+
C, which is derived from life1 ) = 0.63 e fm intime measurement.3) According to Ref. 2, the 2+
1 stateis a rotational excited state, and the symmetric axisof neutron density is perpendicular to the rotational
axis, while that of proton density is aligned to the rotational axis. Namely, the 2+
1 state is dominated byneutron excitation.
In order to search for the possible diﬀerent proton and neutron contributions to the excitation of the
16
C, an inelastic scattering experiment of
2+
1 state in
16
208
C on aPb target was performed4) applying the
Coulomb-nuclear interference method. The analysis
was carried out phenomenologically with the deformed
potential model, and the Mn /Mp ratio was extracted.
However, this analysis contains some assumptions, andhence, it seems inappropriate to test the validity of the
AMD result by comparing the Mn /Mp ratio calculated
by AMD with that evaluated in Ref. 4.
The simplest procedure to test the AMD result may
be to calculate the diﬀerential cross sections of the inelastic scattering of 16 C on a 208 Pb target by the microscopic coupled-channels (MCC) method using the16
C internal wave function obtained by AMD, and tocompare the calculated result with the experimental
reaction data measured in Ref. 4.
In the MCC calculation, the diagonal and coupling
potentials are given by the double-folding model:

(a)
(A)
Vα(ij)α (k) (R) = ρik (ra )ρj (rA )× vN N (ra + R − rA )dra drA ,
(a)

(1)

(A)

where ρik (ρj ) represents the transition density of
the 16 C (208 Pb) nucleus between the state i (j) in channel α and the state k () in channel α , and vN N is the
DDM3Y interaction.5)
Here, we use the AMD wave function to calculate(a)ρik (ra ). In Ref. 2, two versions of the 16 C internal
wave function are obtained in the variation before projection (VBP) formalism, for which the strength of the∗1∗2

spin-orbit force is changed: (a) uls = 900 MeV and (b)uls = 1500 MeV. In addition to them, we also use the
AMD wave function for which the strength of the spinorbit force is set to (c) uls = 2000 MeV so as to reducethe B(E2) value. The B(E2) values obtained with+these three wave functions are B(E2; 2+
1 → 01 ) = 1.9,
4
1.4, and 0.93 e2 fm , respectively. The density distribution of the 208 Pb nucleus is obtained by unfolding
the measured charge form factor6) with the realistic
proton charge form factor7) and it is assumed that theshape of the neutron density is the same as that of the
proton density, namely ρn (r) = (N/Z)ρp (r).
The Coulomb potential is also given by the doublefolding model. The double-folded Coulomb potential iswritten in the same form as Eq. (1), except for certain
inputs: the proton transition densities and Coulomb
force are substituted in place of the matter transition
densities and vN N , respectively. The imaginary partof the nuclear potential is assumed to be the same as
the real part multiplied by a factor NI . In the current
calculation, we choose NI = 1.2. We have found that
the NI dependence of the calculated diﬀerential crosssections was very weak.
The results of the MCC calculations with the AMD
internal wave functions of cases (a) and (b) reproduce the experimental data well without introducing
any normalization factor for the calculated diﬀerential
cross sections, while the result with the wave functionof case (c) underestimates the measured diﬀerential
cross sections. The present result indicates that the
AMD wave functions of cases (a) and (b) are better
than that of case (c).
References
1) Y. Kanada-En’yo and H. Horiuchi: Phys. Rev. C 55,
2860 (1997).
2) Y. Kanada-En’yo: Phys. Rev. C 71, 014310 (2005).
3) N. Imai et al.: Phys. Rev. Lett. 92, 062501 (2004).
4) Z. Elekes et al.: Phys. Lett. B 586, 34 (2004).
5) M. El-Azab Farid and G. R. Satchler: Nucl. Phys. A
438, 525 (1985).
6) H. de Vries et al.: At. Data Nucl. Data Tables 36, 495(1987).
7) T. Janssens et al.: Phys. Rev. 142, 922 (1966).

Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Department of Physics, Osaka City University

17

RIKEN Accel. Prog. Rep. 38 (2005)

Nuclear radius deduced from proton diﬀraction by a black nucleus†
A. Kohama, K. Iida, and K. Oyamatsu∗[Nuclear reaction, Proton elastic scattering, Nuclear radius]
Size of atomic nuclei, one of the most fundamental
nuclear properties, remains to be determined precisely.
Most commonly, the size is deduced from electron andproton elastic scattering oﬀ nuclei.1,2) The charge radii
are well determined due to our full understanding of
the underlying electromagnetic interactions, while deduction of the matter radii from the proton-nucleus
scattering data depends on scattering theory, which ismore or less approximate in the sense that the nucleonnucleon interactions involved are not fully understood.
During the past three decades there have been many efforts to deduce the matter density distributions, which
are based on various scattering theories incorporating
empirical nucleon-nucleon scattering amplitudes, such
as Glauber theory and nonrelativistic and relativistic
optical potential methods. A systematic analysis of
the data for a large number of nuclides, however, isstill missing.
In this work, we propose a new method of deducing the root-mean-square (rms) matter radii, which is
powerful enough to allow us to perform such a systematic analysis. This method, in which we assume thatthe target nucleus is completely absorptive to the incident proton and hence acts like a “black” sphere,3)
is far simpler than the conventional methods, since, inthe present method, one has only to analyze the proton elastic scattering data around a maximum in thesmall-angle regime.
In this method, a nucleus is viewed as a black sphereof radius a. A diﬀraction pattern of protons by thissphere is equivalent to that of the Fraunhofer diﬀraction by a circular hole of the same radius embedded
in a screen. We determine a in such a way that thec.m. scattering angle [θc.m. ≡ 2 sin−1 (q/2p)] of theﬁrst maximum for the Fraunhofer diﬀraction agrees
with that measured by proton-nucleus elastic scattering, θM . (Here, we deﬁne the zeroth peak as thatwhose angle corresponds to θc.m. = 0.) We remarkthat the diﬀraction patterns for θc.m.  θM are distorted by multiple scattering eﬀects, which are beyond
the scope of the black sphere picture. The radius, a,and the angle, θM , are then related by
2pa sin(θM /2) = 5.1356 · · · .

(1)
It is useful to identify this radius multiplied by 3/5
with the root-mean-square matter radius of the target
nucleus:†∗18

Condensed from the article in Phys. Rev. C 69, 064316(2004)
Department of Media Theories and Production, Aichi
Shukutoku University


3/5a.
(2)

The factor 3/5 comes from the assumption that thedensity distribution of the black sphere is uniform.
Combining Eq. (2) with Eq. (1), we may thus write
rBS ≡

rBS =

3.9780 · · ·.
2p sin(θM /2)(3)

For most of stable isotopes of masses heavier than50, the values of rBS that can be determined from
Eq. (3) agree well with the values of the rms matterradius, rm , deduced from elaborate scattering theories
in previous works, at proton incident energies higher
than ∼800 MeV as shown in Fig. 1.

Fig. 1. rBS vs. rm for stable nuclei of masses above 50,
such as 54 Fe, 58,60,62,64 Ni, 90 Zr, 116,124 Sn, and 208 Pb.
The values of rBS and rm are derived from the data for
proton incident energies higher than ∼800 MeV. The
uncertainties of rBS come from those of θM . The crosses(×) denote the rms matter radii of the point nucleon
distributions, and the circles (◦) denote those foldedwith the nucleon form factor. The dotted line represents
rBS = rm . Inset: rBS vs. rm for Ni isotopes.

References
1) C. J. Batty, E. Friedman, H. J. Gils, and H. Rebel: Adv.
Nucl. Phys. 19, 1 (1989).
2) B. Frois, C. N. Papanicolas, and S. E. Williamson: inModern Topics in Electron Scattering, edited by B. Frois
and I. Sick (World Scientific, Singapore, 1991), p. 352.
3) G. Placzek and H. A. Bethe: Phys. Rev. 57, 1075
(1940).

RIKEN Accel. Prog. Rep. 38 (2005)

Variation after parity projection calculation with Skyrme interaction
for light nuclei†
H. Ohta,∗1 K. Yabana,∗2 and T. Nakatsukasa∗2[NUCLEAR STRUCTURE]
Among theories beyond the static mean ﬁeld, thevariation after the projection (VAP) method is one of
the simplest ones. Yet, practical applications with realistic eﬀective interactions, such as the Skyrme interaction, have not been fully investigated even for projection with respect to just the parity. The variation
after the parity projection (VAPP) with a symmetryviolating intrinsic state leads to the ground state including certain octupole correlations. In addition, one
can obtain a negative-parity excited state which is either a collective or non-collective excitation. In thispaper, we propose an algorithm for the calculationof the VAPP with the Skyrme interaction on threedimensional (3D) Cartesian coordinates. Calculations
with the simple BKN interaction were reported previously.1)
In ordinary mean-ﬁeld calculations, one ﬁnds selfconsistent solutions with the axial and reﬂection symmetries for most nuclei. However, in VAPP calculations, the self-consistent solutions violate these symmetries. This symmetry violation in the intrinsic stateis a consequence of the correlation beyond the meanﬁeld, which can be regarded as the octupole correlation. This is similar to the cluster correlation in lightsystems. In Table 1, we show the deformation parameters of the ground and excited states. The VAPP with
the Skyrme interaction (SGII) leads to a cluster structure of α + 16 O in 20 Ne. The positive-parity solution
has a substantial β30 deformation, which is consistent
with the α + 16 O cluster structure. There are two solutions in the negative-parity sector. The lowest energy solution has a small β32 deformation as well asa prolate deformation. The next solution has a large

Table 1. Calculated and experimental excitation energies(Ex ) for 20 Ne. We also show the quadrupole and octupole deformations in the intrinsic states.
KπEx
Ex (exp)
β2
γ
β30
β32
†
∗1
∗2

0+ (J = 0)
g.s.
g.s.
0.535
0.0
0.314
0.0

2− (J = 2)
4.91 (MeV)
4.97 (MeV)
0.589
0.0
0.0
0.178

0− (J = 1)
6.42 (MeV)
5.78 (MeV)
0.694
0.0
0.576
0.0

Condensed from the article in Phys. Rev. C 70, 014301(2004).
Institute of Physics, University of Tsukuba
Center for Computational Sciences, University of Tsukuba

β30 deformation as well as β2 . The former solution
is characterized by K π = 2− and the latter solution
by K π = 0− . The K π = 0− state can be interpreted
as a parity partner of the ground state. Clustering isstronger in the negative-parity solution.
The angular momentum projection after the variation gives rotational spectra and transition strengths(Table 2). The calculated B(E2) values agree well withexperimental data, except for the terminating spin,
J = 8 h̄. Since, in this work, each rotational bandis constructed from a single intrinsic state, the angularmomentum dependence of B(E2; Ji → Jf ) is similar
to that of the rotational model.
We also carry out the VAPP calculation for 12 C. To
obtain a reasonable agreement with experiments, wemust reduce the spin-orbit force in the SGII interaction(and most versions of the Skyrme as well). Introducing
a reduction factor of 0.8 for the spin-orbit force, we areable to reproduce experimental positive- and negativeparity bands. It turns out that the ground state has alarge β33 deformation with an oblate shape, which isconsistent with the 3α clustering structure.
Table 2. Calculated intraband B(E2) strengths for theK π = 0+ and K π = 2− bands in 20 Ne. The first column indicates the initial and final spins/parities. For
comparison, we show the values of the rotational model(B(E2)rot ). The values in brackets are adjusted to experimental values. The experimental values2) are listed
in the last column.
Jiπ → Jfπ2+ → 0+ (K = 0)
4+ → 2+6+ → 4+8+ → 6+3− → 2− (K = 2)
4− → 3−4− → 2−5− → 4−5− → 3−6− → 5−6− → 4−B(E2)cal(e2 fm4 )
41.6
59.9
67.5
75.1
97.6
73.5
32.9
52.6
53.1
39.7
67.0

B(E2)rot(e2 fm4 )(57.0)
81.4
89.7
93.9
101
75
(34)
53
53
39
66

B(E2)exp(e2 fm4 )57 ± 871 ± 766 ± 824 ± 8113 ± 2977 ± 1634 ± 6< 808
84 ± 1932 ± 1355 +23−13

References
1) S. Takami, K. Yabana, and K. Ikeda: Prog. Theor.
Phys. 96, 407 (1996).
2) O. Häusser et al.: Nucl. Phys. A 168, 17 (1971).

19

RIKEN Accel. Prog. Rep. 38 (2005)

Direct inclusion of the tensor contribution in the cluster model andmechanism of the appearance of cluster structure in light nuclei
N. Itagaki,∗1 S. Aoyama,∗2 S. Okabe,∗3 and K. Ikeda[NUCLEAR STRUCTURE, CLUSTER MODEL]
Recently, theoretical investigations of light nuclei
based on a realistic nucleon-nucleon interaction havebecome feasible. For example, it is surprising that thequantum Monte Carlo calculation has microscopicallyshown the appearance of an α-α cluster structure in8
Be based on a realistic nucleon-nucleon interaction.1)
Despite this situation, it should be mentioned thatcluster models are still useful in describing very exotic cluster structures or intruder states of excess neutrons. Therefore, what we are going to do is to reﬁne
further the eﬀective interactions used in the conventional cluster models to include the nature of the original nucleon-nucleon interaction, keeping a large model
space for describing both exotic cluster and standard
shell structures.
One of the key issues concerning the eﬀective interactions used in the conventioanl cluster models that must
be improved is the direct treatment of tensor terms,
which has been renormalized in the central part of theeﬀective interaction used in most cluster studies. Recently, several attempts of directly taking into accountthe tensor part of the interaction in microscopic clustermodels have been started,2) and a strong contribution
has been discussed, for example, in the 4 He nucleus.
However, if the tensor interaction is directly treated,the central part of the eﬀective interaction has to be
modiﬁed completely. Therefore, we perturbatively include a weakened tensor interaction as a ﬁrst step,which is ﬁtted to reproduce the tail part of the onepion exchange potential (OPEP) with its inner partbeing weakened. By adding this tensor interaction,
the long-range nature of the pion exchange potential
is taken into account. In addition to the tensor term,
we adopt the Volkov interaction for the central partand the G3RS potential for the spin-orbit part, andthe strenght of the triplet-even channel of the Volkov
interaction is reduced to adjust the binding energies oftwo- and three-nucleon systems.
The energy convergence of 4 He is shown in Fig. 1 asa function of the number of wave functions of antisymmetrized molecular dynamics (AMD). Both the resultsof the studies with and without the tensor interaction
are presented. The energy obtained without the tenser
terms converges around −23.3 MeV, but the binding
energy becomes larger by about 4.4 MeV by introducing the present tensor term. The expectation value of
∗1
∗2
∗3

20

University of Tokyo
Niigata University
Hokkaido University

Fig. 1. The energy convergences of 4 He as a function of
number of trial AMD Slater determinants (horizontalaxis).

the tensor interaction is −6.4 MeV; however, the increase in the kinetic energy by 2.0 MeV compared tothe case without the present tensor term compensatesit.
Furthermore, we can study the validity of one of themost fundamental bases of the mechanism of the appearance of a cluster structure. In the 1960s, a microscopic α-α potential was derived based on the meson
theory,3) and it was found that an α-α structure has alarge relative distance, since the contribution of OPEP
vanishes from the direct terms, when each α-cluster is
described as the (0s)4 conﬁguration. Therefore, aninteraction between α-clusters is weak and a cluster
structure appears in 8 Be. Using such a microscopic
potential, it has been possible to reproduce the phaseshift of α-α scattering. This idea has been generalized as the threshold rule, which has been proposed
as a mechanism to explain the appearance of exotic
clustering. Using our interaction, the contribution of
the tensor interaction becomes important at an α-αdistance of 3 fm, and it does not eliminate the clustering of the system. The picture of the “weak interaction” between two 4 He nuclei is still valid, although
the model space of the wave function is much extended
compared to the (0s)4 conﬁguration.
References
1) R. B. Wiringa, S. C. Pieper, J. Carlson, and V. R.
Pandharipande: Phys. Rev. C 62, 014001 (2000).
2) S. Sugimoto, K. Ikeda, and H. Toki: Nucl. Phys. A 740,
77 (2004).
3) I. Shimodaya, R. Tamagaki, and H. Tanaka: Prog.
Theor. Phys. 27, 793 (1962).

RIKEN Accel. Prog. Rep. 38 (2005)

Cluster-shell competition in light nuclei†
N. Itagaki,∗1 S. Aoyama,∗2 S. Okabe,∗3 and K. Ikeda[NUCLEAR STRUCTURE, Cluster model, Unstable nuclei]
Nuclei are quantum many-body systems consistingof protons and neutrons, and these nucleons have been
known to form some self-consistent mean ﬁeld and to
perform independent-particle motions. The nuclear
shell-model, which is one of the standard models forthe nuclear structure, is based on this assumption,and the strong spin-orbit interaction in the mean ﬁeld
has been known to be a key mechanism that fully explain the observed magic numbers. On the other hand,the α-particle, which corresponds to the doubly closed
shell of the lowest s-shell in the shell model, is strongly
bound, and since the relative α-α interaction is weak,strongly interacting four nucleons (α-particle) becomea subunit of the nuclear structure in some light nuclei,
contrary to the mean-ﬁeld models.
If an α-cluster is expressed as the lowest (s1/2 )4 conﬁguration, it is a spin-zero system, and non-central
interactions do not contribute to it. However, the dissolution of the α-cluster should be taken into accountin the systems, where the spin-orbit interaction, which
is a characteristic interaction in the mean-ﬁeld picture,strongly acts. Therefore, it is intriguing to study thecluster-shell competition for a uniﬁed understanding of
the nuclear structure.
The antisymmetrized molecular dynamics (AMD)has been proposed to demonstrate this eﬀect and extensively applied to calculating the properties of lightstable and neutron-rich nuclei,1) and we superimpose
many AMD wave functions based on AMD — superposition of selected snapshots (AMD triple-S).2) Here,the Gaussian centers for each nucleon are randomly
generated and only their imaginary parts are optimized by solving the cooling equation. Then, we select important Slater determinants from the trial AMD
wave functions. For the central part of the interaction, we use the Volkov eﬀective N − N potential with
M = 0.60 and B = H = 0.125. For the spin-orbit
term, we introduce the G3RS potential with a strengthof V0 = 2000 MeV.
The energy convergence of 12 C is shown in Fig. 1,
here, the horizontal axis is the number of trial AMD
wave functions. The basis states from 1 to 100 havevarious conﬁgurations of 3α, and those from 101 to
600 have a α+α+2p+2n model space (relative α-α distances of 2, 3, and 4 fm). Here, the decrease in energy
from the 3α-model is 5.2 MeV due to the strong spin†
∗1
∗2
∗3

Condensed from the article in Phys. Rev. C 70, 054307(2004)
University of Tokyo
Niigata University
Hokkaido University

Fig. 1. The energy convergence of 12 C (0+ ) with respect tothe number of trial AMD basis states.

orbit interaction. Furthermore, the shell model-likewave functions of the α+4p+4n model space are added(from 601 to 800), where two of α-clusters are broken.
However, the decrease in energy by adding these basis
states is only about 1 MeV, and it is considered thatthe contribution of the spin-orbit interaction is almost
taken into account when one of the α-clusters is broken.
On the other hand, the calculated second 0+ state(observed at Ex = 7.65 MeV) mainly has the 3αcomponent. In stellar nucleosynthesis, the second 0+
state above the 3α threshold plays a crucial role informing 12 C. It is formed as a triple-α resonance stateand decays ﬁrst to the 2+ state and next to the ground+0+ state by emitting γ-rays. The B(E2, 0+
2 → 21 )12value strongly aﬀects the abundance of C; however, it
has been about one-half in the conventional 3α model
based on the resonating group method (RGM).3) In thepresent case, the mixing of 3α and α-breaking components aﬀects the B(E2) value and it becomes consistent
with the experimental value.
It can be summarized that for nuclei 8 Be, 10 Be, and10
B, the increase in binding energy when the breaking
of one of the α-clusters is taken into account is about
2 MeV, and essentially the α+α structure is the dominant conﬁguration of the ground states. However, theincrease is very large in 12 C (5.2 MeV).
References
1) Y. Kanada-En’yo and H. Horiuchi: Prog. Theor. Phys.
93, 115 (1995).
2) N. Itagaki, A. Kobayakawa, and S. Aoyama: Phys. Rev.
C 68, 054302 (2003).
3) M. Kamimura: Nucl. Phys. A 351, 456 (1981).

21

RIKEN Accel. Prog. Rep. 38 (2005)

Eﬀects of ground-state correlations beyond RPA
in light exotic nuclei
N. Dinh Dang and N. Vinh Mau∗

NUCLEAR STRUCTURE, random-phase approximation, ground-state correlations, exotic
nucleiThe random-phase approximation (RPA) has been
a powerful tool in the theoretical study of many-bodysystems such as atomic nuclei. An essential ingredientof the RPA is the use of the quasiboson approximation (QBA), which considers fermion pairs as boson
operators, just neglecting the Pauli principle between
them. Within the QBA a set of linear equations, which
is usually called the RPA equation, is derived, whichmakes computationally demanding problems become
tractable. The success of RPA depends on the validity of the QBA, which turns out to be very good in
medium and heavy nuclei.
With increasing interest in light exotic nuclei, theparticle-particle (pp) RPA has been applied recently tothe calculations for 14 C, 12,14 Be, and 11 Li.1) However,in light systems, due to strong ground-state correlations (GSC) beyond RPA2) the validity of the QBA
becomes questionable.
In the present study we used the renormalized pp
RPA (RRPA) to take into account the eﬀects of GSC
beyond RPA due to Pauli principle between fermion
pairs in the calculations for 12,14 Be. The calculations
were based on the set of RRPA equations for the systems with a core ±2 neutrons. As the inputs thecalculations used the Gogny interaction and neutronstates up to an energy c  10 MeV. The continuum
states are discretized using a box with a radius of 20 fm.
The parameter of the particle-phonon coupling in the
one-neutron potential was ﬁtted to reproduce the experimental 1p1/2 , 2s, 1d5/2 single-neutron energies for∗

22

Institut de Physique Nucléaire, France

12

Be. The inversion of 1p1/2 and 2s shells was assumed
with 2s shell being the last occupied one with an energy
given by the one-neutron separation energy, while theenergy of the 1p1/2 shell was ﬁtted to 0.7 MeV in orderto reproduce approximately within RPA the experimental two-neutron separation energy in 14 Be, whichis equal to S2n = 1.34 ± 0.11 MeV.
The results of calculations show that GSC beyond
RPA have strong eﬀects on the ground-state andcorrelation energies in these light exotic nuclei. In
12
Be the GSC shift up the ground-state energy by
13.6%, from −3.614 MeV (RPA result) to −3.122 MeV(RRPA result), and the correlation energy by 21%,from −2.1 MeV (within RPA) to −1.66 MeV (within
RRPA). Quite stronger eﬀects are obtained in 14 Be,
where the ground-state energy increases by 50%,
from −1.391 MeV (within RPA) up to −0.695 (within
RRPA), and the correlation energy increases by around25%, from −2.22 MeV (within RPA) up to −1.66 MeV(within RRPA). We also found that the violation ofparticle number due to using the GSC factor of thetype introduced in Ref. 3 is negligible (∼ 0.1%).
References
1) J. C. Pacheco and N. Vinh Mau: Phys. Rev. C 65,
044004 (2002).
2) F. Catara, N. Dinh Dang, and M. Sambataro: Nucl.
Phys. A 579, 1 (1994).
3) J. Dukelsky and P. Schuck: Phys. Let. B 464, 164(1999).

RIKEN Accel. Prog. Rep. 38 (2005)

Particle-number conservationin the self-consistent random-phase approximation
N. Dinh Dang
[NUCLEAR STRUCTURE, random-phase approximation, ground-state correlations]
The random-phase approximation (RPA) is usuallyderived within the quasiboson approximation, neglecting the Pauli principle between fermion-pair operators.
As a result, the RPA equation yields imaginary solutions at a certain critical value of the interaction parameter. Several approaches have been developed toremove this inconsistency of the RPA. The popular
one among them is the renormalized RPA (RRPA),1,2)
which avoids the collapse of RPA. However, the tests
carried out within exactly solvable models showed that
there is still a large discrepancy between the solution obtained within the RRPA and the exact one.
Recently, the self-consistent RPA (SCRPA)3) has included the expectation values of the products of two
fermion pairs in the correlated ground state as screening corrections. As a result, within a particle-hole(ph) symmetric multilevel-pairing model with double degeneracy (the so-called picket-fence model), the
SCRPA yielded the solutions very close to the exact
ones for the correlation energy of the system with Ωparticles, as well as the energy of the ﬁrst excitedstate of the system with Ω + 2 particles.3) Realistic
nuclear single-particle spectra are in general ph nonsymmetric. It is, therefore, worthwhile to reexamine
carefully the SCRPA before applying it to realistic nuclei.
This work shows that, within a multilevel-pairingmodel with double degeneracy, the expressions foroccupation numbers used in the original version
of SCRPA3) violate the particle number for nonsymmetric particle-hole (ph) spectra. A renormalization is introduced to restore the particle number, whichleads to the expressions of occupation numbers similar
to those derived by Hara et al. for the ph case.1) The
results of calculations within the ph symmetric caseshow that this number-conserving SCRPA yields theenergies of the ground state and ﬁrst excited state of
the system with Ω + 2 particles relative to the groundstate of the system with Ω particles in close agreementwith those obtained within the original SCRPA. However it gives a slightly larger correlation energy (seeFig. 1).
References
1) K. Hara: Prog. Theor. Phys. 32, 88 (1964); K. Ikeda, T.
Udagawa, and H. Yamamura: Prog. Theor. Phys. 33,
22 (1965).
2) F. Catara, N. Dinh Dang, and M. Sambataro: Nucl.
Phys. A 579, 1 (1994).

Fig. 1. (a) Particle-number violations within SCRPA forph non-symmetric cases with particle number Ω = 10
and number of hole levels Ωh = 1 (solid line), 2 (dashedline), 3 (dotted line), and 4 (dash-dotted line) as functions of interaction parameter G (in units of the level
distance ). (b) Correlation energy Ecorr in the system with 10 particles, and (c) ﬁrst-excited-state energy E2 of the system with 12 particles relative to theground-state of the system with 10 particles obtained
within RPA (dotted line), RRPA (dash-dotted line),
SCRPA (thick solid line), number-conserving SCRPA(thick dashed line), and exact (thin solid line) calculations.
3) J. Dukelsky and P. Schuck: Phys. Let. B 464, 164(1999).

23

RIKEN Accel. Prog. Rep. 38 (2005)8

Be in the charge- and parity-projected Hartree-Fock method
S. Sugimoto, K. Ikeda, and H. Toki∗

NUCLEAR STRUCTURE, Mean ﬁeld model, 8 Be

Recently, we have developed a new mean-ﬁeld-typemodel that can treat the tensor force by breaking
the parity and charge symmetries of single-particle
states.1,2) We call this model the charge- and parityprojected Hartree-Fock (CPPHF) method, because thecharge and parity projections are performed before thevariation. We applied the CPPHF method to the caseof the alpha particle and found that it is eﬀective intreating the tensor correlation and both the charge andparity projections are important in obtaining a ﬁnite
energy from the tensor force in the alpha particle.2)
The cluster aspects of nuclei are very interesting andgenerally appear in a light mass region. 8 Be is a typical alpha-clustering nucleus and studied extensively
using various methods. Some of these studies showthat the tensor force is important in alpha clustering.
The recent exact calculations clearly show that 8 Be
consists of weakly bounded two alpha clusters and thelarge amount of the attractive energy comes from theone-pion-exchange potential.3) This indicates that thetensor force is important in alpha clustering, because
the one-pion-exchange potential has a strong tensor
part. Therefore, it is interesting to study 8 Be using
the CPPHF method to study the eﬀect of the tensor
force on alpha clustering.
In the present study, we use the wave function of
the alpha particle obtained in the CPPHF method,Φα , and calculate the energy surface of two alpha particles as a function of relative distance. The parity
and charge projections are performed for each alphaparticle as p
8cΨ Be (1, . . . , 8) = N A1−8 P1−4P1−4
Φα (1, . . . , 4)

p
c
(1)
× P5−8 P5−8 Φα (5, . . . , 8) .
In the above equation, A1−8 is the antisymmetrizap
ction operator for eight particles, Pa−b
and Pa−barethe parity and charge projection operators for the particle numbers a to b, and N is the normalization factor.
As for the Hamiltonian, we use the Volkov No. 1 force
for the central part4) and the G3RS force for the tensor
part.5) We multiply XTE for the 3 E part of the central
force and XT for the τ1 · τ2 part of the tensor force.
In Fig. 1, we show the energy surfaces for threecases. The solid line indicates the energy surface forthe case with no tensor force and XTE = 1.0 in the∗24

Research Center for Nuclear Physics (RCNP), Osaka University

Fig. 1. Energy surface for 8 Be as a function of the relative
distance between alpha particles, R.

parity-projected Hartree-Fock calculation, the dashedline with XT = 1.5 and XTE = 0.95 in the parityprojected Hartree-Fock calculation, and the dotted linewith XT = 1.5 and XTE = 0.8 in the charge- andparity-projected Hartree-Fock calculation. XT and
XTE are determined to reproduce the binding energy of
the alpha particle. Here, the parity-projected HartreeFock calculation means that we only perform the parity projection when we calculate the alpha particle and8
Be. From the ﬁgure, we can see that when the tensor
correlation is introduced to the calculation of the alphaparticle, the energy surface steeply goes up comparedwith the no-tensor-force case. This eﬀect is mainly
caused by a large increase in kinetic energy due to thedecrease in relative distance. The large increase in kinetic energy is probably due to the p-state mixing inthe single-particle states in the alpha particle inducedby the tensor force. In this sense, we can say that thetensor correlation signiﬁcantly aﬀects the inner regionof the energy surface of 8 Be.
References
1) H. Toki, S. Sugimoto, and K. Ikeda: Prog. Theor. Phys.
108, 903 (2002).
2) S. Sugimoto, K. Ikeda, and H. Toki: Nucl. Phys. A 740,
77 (2004).
3) R. B. Wiringa, S. C. Pieper, J. Carlson, and V. R.
Pandharipande: Phys. Rev. C 62, 014001 (2001).
4) A. Volkov: Nucl. Phys. 74, 33 (1965).
5) R. Tamagaki: Prog. Theor. Phys. 39, 91 (1968).

RIKEN Accel. Prog. Rep. 38 (2005)

Systematic study of E2 transition strengths of C isotopes
Y. Kanada-En’yo∗[NUCLEAR STRUCTURE, Unstable nuclei, Cluster]16
C has
Recently, the life time of the 2+
1 state of1)
been measured. It indicates the abnormally small E2+24transition strength as B(E2; 2+
1 → 01 ) = 0.63e fm
16
10
in C, compared with those for other C isotopes ( C,12
C and 14 C). As well known, B(E2) has a close relation to the intrinsic deformation of the nucleus. Considering the excitation energy Ex (2+1 ) = 1.766 MeV of
16
C, this nucleus is expected to have a deformed structure. In case of normal stable nuclei, B(E2) values
tend to be large in the deformed nuclei. It means that+16
C seems to
the hindrance of the B(E2; 2+
1 → 01 ) in
contradict with the large deformation expected fromthe excitation energy Ex (2+1 ).
In the theoretical work on C isotopes,2) it was suggested that the diﬀerent shapes between proton andneutron densities may cause the suppression of B(E2).
In this paper, we perform systematic analysis of thedeformations of proton and neutron densities in eveneven C isotopes based on calculations of antisymmetrized molecular dynamics (AMD),3) and discuss
the E2 transition strengths in neutron-rich C isotopes
in relation to the deformations.
We applied the simplest version of AMD to eveneven C isotopes. The excitation energies of 2+
1 andthe E2 transition strengths are shown in Table 1. Sys-

Table 1. Excitation energies (MeV) of the 2+
1 states and+2
4
B(E2; 2+
1 → 01 ) (e fm ) in C isotopes calculated by
AMD method. The adopted interaction consists of thecentral force of MV1 (m = 0.576) and the spin-orbit
force of GSRS (uls = 1500 MeV), and Coulomb.
10

C

12

C

14

C

cal.
exp.

Ex (2+1 )
Ex (2+
1 )

1.95
3.354

1.66
4.439

3.75
7.012

cal.
exp.

B(E2)
B(E2)

5.4
12.4 ± 0.2

6.8
8.2 ± 0.1

5.9
3.74 ± 0.5

16

18

20

C

C

C

cal.
exp.

Ex (2+1 )
Ex (2+
1 )

0.65
1.766

0.87
1.59§10.88
1.59§1

cal.
exp.

B(E2)
B(E2)

1.4
0.63

0.6§2
−

5.0
−

§1

The experimental data for 18 C and 20 C are taken from
Ref. 4.
§2
The theoretical B(E2) in 18 C is sensitive to thestrength of spin-orbit force (see Ref. 5).
∗

tematics of the experimental B(E2) values in the series of C isotopes is well described by the calculations.
The results indicate that the neutron shape drastically changes with the increase of neutron number,while the proton shape is rather stable. It is suggested
that the diﬀerence between proton and neutron shapes
may appear in 16 C and 18 C as well as 10 C. Namely,
the oblate nature of the proton shape still remains,though the neutron structure is prolate or triaxial inthese isotopes. We analyze the E2 transition strength
in relation to the deformation. The unusually small+
16
C, which has been recently meaB(E2; 2+
1 → 01 ) in
sured, was described by the coexistence of the oblate
proton shape and the prolate neutron shape. In otherwords, the deviation between the proton and neutron
shapes is important in the hindrance of B(E2). Ac+
cording to the present prediction, the B(E2; 2+
1 → 01 )18
16
in C is as small as that in C, while the B(E2) islarger in 20 C. The present results also show the enhancement of the neutron skin structure in neutronrich C. It was found that the stable proton structure
in C isotopes plays an important role in the neutron
skin structure as well as in the systematics of B(E2).
The present results tend to underestimate the excitation energies Ex (2+1 ) in general, though the systematic behavior of Ex (2+1 ) in the series of C is reproduced.
One of the reason for the underestimation of Ex (2+1)
may be the paring eﬀect, which is not suﬃciently taken
into account in the simplest AMD. Such extension of
the framework as the variation after projection and superposition will improve the results. Here, we would
like to mention that the neutron excitation is dominant
16
C and 18 C. Therefore, the excitain the 2+
1 states of+tion energy Ex (21 ) is related to the neutron structure
rather than proton structure. In the analysis of the208
Pb+16 C inelastic scattering,6) the dominant contribution of the neutron excitation in the 2+
1 state is supported by the experimental data.
References
1) N. Imai et al.: Phys. Rev. Lett. 92, 062501 (2004).
2) Y. Kanada-En’yo and H. Horiuchi: Phys. Rev. C 55,
2860 (1997).
3) Y. Kanada-En’yo and H. Horiuchi: Prog. Theor. Phys.
Suppl. No. 142, 205 (2001); Y. Kanada-En’yo, M.
Kimura, and H. Horiuchi: C. R. Physique 4, 497 (2003).
4) M. Stanoiu et al.: Eur. Phys. J. A 20, 95 (2004).
5) Y. Kanada-En’yo: Phys. Rev. C. 71, 014310 (2005).
6) Z. Elekes et al.: Phys. Lett. B 586, 34 (2004).

Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)25

RIKEN Accel. Prog. Rep. 38 (2005)

Study of unstable nuclei with an extended cluster-orbital shell model
H. Masui,∗1 T. Myo,∗2 K. Katō,∗3 and K. Ikeda[Nuclear structure, Unstable nuclei, Cluster model]
The recent development of experiments for unstable
nuclei shows diﬀerent aspects from the stable nuclei.1)
The observed 23 O r.m.s radius is large compared withthe empirical low A1/3 . An experimental analysis using
the Glauber theory suggests that 23 O is not a simple
22
O core plus one valence neutron structure2) from theanalysis of the spin parity of the ground state, which is
5/2+ . However, there is another experimental analysis,
which shows that the ground state of 23 O is 1/2+ .3)
Therefore, a theoretical study with a high accuracy andan ability of describing the halo structure is required.
To study such a complex halo structure, we develop
a method using the cluster-orbital shell model (COSM)
and extend it so as to be able to treat the dynamics
of the total system. For treating the dynamics of thecore, we introduce the degrees of freedom for the widthparameter b. The energy of the core and the potential
between the core and valence nucleons, which is constructed microscopically, are connected to each otherby the core b width parameter.
The energy of the core can be calculated analytically,
if we use the lowest conﬁguration for the core.4) In thisformalism, the core-N potential is a folding-type potential using the core density. Hence, the change in b
aﬀects the shape and strength of the core-N potential.
The optimum value of b can be determined by combining the core and core-N parts. To reproduce theasymptotic shape of the core-N wave function, the radial part is expressed by a linear combination of Gaussian basis functions. Using such Gaussian basis functions, the motion of valence nucleons is solved by thestochastic variational method (SVM).5) We call thisapproach “Neo-COSM”.
We use the eﬀective nucleon-nucleon potential,
Volkov No. 2 with the exchange parameter m = 0.58.
For valence nucleons, we artiﬁcially introduce theHeisenberg and Bertrett parameters as h = b = 0.07
to adjust the ground-state energy of 18 O.
First, we perform the calculation at a ﬁxed b. For
oxygen isotopes, the binding energies and r.m.s. radiiof the isotopes are well reproduced. On the other hand,for N = 8 isotones (the 16 O+Xp systems), the calculated r.m.s. radii do not reach the observed values,
while the calculated binding energies of the isotones
are well reproduced. The results for the r.m.s. radii at

∗1
∗2
∗3

26

Information Processing Center, Kitami Institute of Technology
Research Center for Nuclear Physics, Osaka University
Department of Physics, Hokkaido University

a ﬁxed b are shown in Fig. 1 (a).
The diﬀerence between the 16 O+Xn and 16 O+Xp
systems suggests that we need to introduce a newmechanism or improve the description of the system,
which includes the improvement of the interaction.
Therefore, to reproduce the diﬀerence, we performed
the Neo-COSM calculation by changing the core b parameter. The energy of the core is calculated analytically. Hence, b is determined by searching the minimum point of the energy in the total system. By performing the above calculation, the obtained r.m.s. radii
are qualitatively improved from the ﬁxed-b Neo-COSM
calculation, as shown in Fig. 1 (b).
In summary, we developed a new method of studying
the particular structures of neutron- and proton-richnuclei. The essential point of our method is that wetreat the total system by introducing the degrees of
freedom of the core b parameter in the COSM.

Fig. 1. Calculated r.m.s. radii using (a) fixed b and (b) NeoCOSM. Experimental values1) are shown with error
bars.

References
1) A. Ozawa et al.: Nucl. Phys. A 693, 32 (2001).
2) R. Kanungo et al.: Phys. Rev. Lett. 88, 142502 (2002).
3) D. Cortina-Gil et al.: Phys. Rev. Lett. 93, 062501(2004).
4) T. Ando, K. Ikeda, and A. Tohsaki-Suzuki: Prog.
Theor. Phys. 64, 1608 (1980).
5) V. I. Kukulin and V. M. Krasnopol’sky: J. Phys. G 3,
795 (1977).

RIKEN Accel. Prog. Rep. 38 (2005)

Dominance of intruder state in 30 Na†
Y. Utsuno,∗1 T. Otsuka,∗2 T. Glasmacher,∗3 T. Mizusaki,∗4 and M. Honma∗5[NUCLEAR STRUCTURE, Shell model, Unstable nuclei]
Recently, it has been clariﬁed in which nucleus theN = 20 magic structure disappears. In the so-called“island of inversion” picture,1) the region with thedisappearance was restricted to nine N ≥ 20 nuclei,
whereas a recent Monte Carlo shell-model (MCSM)
calculation2) has indicated that certain N = 19 isotopes should have the ground state dominated by the
intruder state, from a comparison with the experimentally determined3) electromagnetic moments of Na isotopes. In the present study, we examine what the dominance of the intruder state in an N = 19 isotope 30 Nameans in terms of the N = 20 shell gap on the basis of
the MCSM calculation. The numerical computations
have been carried out with the Alphleet and Alphleet-2
parallel computer systems as a RIKEN-CNS collaboration project on large-scale nuclear structure calculations.
In order to examine the importance of the narrow
N = 20 shell gap given by the present shell-model
Hamiltonian,4) we artiﬁcially widen the shell gap fromthe original interaction, shifting the strength of themonopole interaction with a control parameter x as
T =1,0(x) = −0.3x, +0.7x MeV,
δV0d
5/2 ,0d3/2(1)where VijT denotes the monopole interaction between
i and j orbits with isospin coupled to T .4) Figure 1
shows some quantities as functions of the shell gap. As
presented in Figs. 1 (a) and (b), both the quadrupole
moment and the magnetic moment of 30 Na suddenly
deviate from values close to the experimental values atthe shell gap ∼ 4 MeV. This is accounted for by thesudden transition of the dominant ground-state component from the intruder state to the normal state as
indicated in Figs. 1 (c) and (d). Compared with thecases of 29 Na and 31 Na, the transition in 30 Na occurs
very sharply and the dominance of the intruder statein this nucleus is thus a rather sensitive probe for theshell gap. The present result supports the argumentthat the shell evolution5) is caused by the spin-isospin
dependence of the eﬀective interaction.

†
∗1
∗2
∗3

∗4
∗5

Condensed from article in Phys. Rev. C 70, 044307 (2004)
Japan Atomic Energy Research InstituteDepartment of Physics and Center for Nuclear Study, University of Tokyo
National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, USA
Institute of Natural Sciences, Senshu University
Center for Mathematical Sciences, University of Aizu

Fig. 1. (a) Quadrupole moment and (b) magnetic momentof 30 Na. The horizontal axis shows the shell gap. The
value of the shell gap is controlled by a parameter x
in Eq. (1), shown by the upper horizontal axis. The
moments determined by the experiment3) and sd-shellmodel are denoted by the squares and crosses, respectively. (c) 2p2h probabilities in the (positive-parity)
ground states of 29–31 Na. (d) Energies of the 2p2hand 1p1h-dominant lowest states of 30 Na (denoted by“2p2h” and “1p1h”, respectively) measured from thatof the 0p0h-dominant lowest state. The range of theshell gap giving the npnh ground state (n = 0, 1, 2) isindicated by nex.

References
1) E. K. Warburton, J. A. Becker, and B. A. Brown: Phys.
Rev. C 41, 1147 (1990).
2) Y. Utsuno, T. Otsuka, T. Mizusaki, and M. Honma:
Prog. Theor. Phys. Suppl. No. 146, 488 (2002).
3) M. Keim: AIP Conf. Proc. 455, 50 (1998); M. Keimet al.: Eur. Phys. J. A 8, 31 (2000).
4) Y. Utsuno, T. Otsuka, T. Mizusaki, and M. Honma:
Phys. Rev. C 60, 054315 (1999).
5) T. Otsuka, R. Fujimoto, Y. Utsuno, B. A. Brown, M.
Honma, and T. Mizusaki: Phys. Rev. Lett. 87, 082502(2001).

27

RIKEN Accel. Prog. Rep. 38 (2005)

Low-lying collective vibrational excitations induced bypairing anti-halo eﬀect
M. Yamagami[Nuclear structure, low-lying vibrational excitations, pairing correlations]
A special interplay of loosely-bound neutrons withsmall orbital angular momentum  and selfconsistent pairing correlations based on the Hartree-FockBogoliubov (HFB) theory in low-lying collective vibrational excitations is studied.1) In general, vibrational excitations are microscopically represented by
the coherent superposition of one-particle one-hole (1p1h) states. In stable nuclei with the deep Fermi energy, 1p-1h states among tightly-bound states mainly
contribute to low-lying vibrational excitations, andthese 1p-1h states spatially concentrate around thesurface region. In contrast, in neutron drip line region, the contributing conﬁgurations are 1p-1h statesamong tightly-bound, loosely-bound, resonant andnon-resonant continuum states.
Because looselybound low- neutrons have an appreciable probability
to be outside the core nucleus, 1p-1h excitations fromloosely-bound low- neutrons to the nearby continuum
states have a spatially extended structure. Such coupling to the continuum states gives rise to a soft excitation with a large transition strength as a non-resonant
single-particle excitation.2) Therefore the realization of
the localization of 1p-1h states is nontrivial in neutron drip line nuclei, and such spatially extended 1p1h states may cause qualitative diﬀerences in low-lying
collective vibrational excitations.
In this study, we emphasize the change in the spatial structure of quasiparticle wave functions in looselybound low- neutrons by selfconsistent pairing correlations, namely, “the pairing anti-halo eﬀect in hole
wave functions” (see Fig. 1), and “the broadening eﬀect
in particle wave functions”. Consequently, the spatial
structure of 1p-1h states changes, and “the extended
localization of 1p-1h states among low-lying quasiparticle states”, that can enhance low-lying collectivity, isrealized.
By performing HFB plus quasiparticle random phaseapproximation (QRPA) calculations with Skyrmeinteraction, we investigate low-lying 2+ states inneutron-rich Ni isotopes. In Fig. 2, the B(E2, 0+
1 →2+)valuesobtained
by
HFB
plus
QRPA
calculations
1
are shown. For comparison, the results obtained byresonant BCS plus QRPA and RPA calculations arealso shown. While approaching the neutron drip line,
the calculated B(E2) values exhibit a diﬀerent behavior; the B(E2) values in HFB plus QRPA increase,but decrease in resonant BCS plus QRPA, and aremuch smaller in RPA. The main qualitative diﬀerence among these calculations is the realization of the28

Fig. 1. The r.m.s radii of the (hole) 3s1/2 and 2d3/2 states
with/without HFB pairing correlations are shown asfunctions of the single-particle energies. The WoodsSaxon potential is used for the mean-field. The densitydependent pairing force is used in the HFB calculation.

+
Fig. 2. The B(E2, 0+
1 → 21 ) values in neutron-rich Ni isotopes obtained by HFB plus QRPA, resonant BCS plus
QRPA, and RPA calculations with Skyrme SLy4 force.

extended localization of 1p-1h states among the lowlying s1/2 , d3/2 and d5/2 quasiparticle states in the
HFB theory.
Finally the eﬀects of quadrupole deformation in lowlying vibrational excitations in neutron drip line nuclei
are examined. We discuss the roles of the breaking of
the rotational symmetry and the mixing of isoscalarand isovector modes in association with the possibilityof new types of vibrational excitation; collective soft
dipole modes with a pear- or banana-shape vibration.
References
1) M. Yamagami: Proc. 5th Japan-China Joint Nuclear
Physics Symp., Fukuoka, 2004-3, edited by Y. Gono, N.
Ikeda, and K. Ogata (Kyushu University, 2004) p. 218;
preprint nucl-th/0404030.
2) H. Sagawa, N. Van Giai, N. Takigawa, M. Ishihara, andK. Yazaki: Z. Phys. A 351, 385 (1995).

RIKEN Accel. Prog. Rep. 38 (2005)

A search for a uniﬁed eﬀective interaction for Monte Carlo shellmodel calculations (VI)
M. Honma,∗1 T. Otsuka,∗2,∗3 and T. Mizusaki∗4[Shell model, Eﬀective interaction]
The Monte Carlo shell model1) (MCSM) has enabled
us to apply the nuclear shell model to various problems
in a huge model space and with many valence nucleons which are not accessible by conventional methods.
However, the eﬀective interaction for a practical use insuch a huge model space is unknown. As shown in ourprevious reports,2) we have been investigating a possibility to construct an eﬀective interaction which canbe used for a uniﬁed description of many nuclei in ahuge model space with a reasonable predictive power,
and have published a possible solution GXPF13) forpf -shell nuclei.
In this report, we discuss our recent trial to describe
heavier nuclei around A = 60–100 in the shell-model
framework. A reasonable choice of the model space is
to include the orbits p3/2,1/2 , f5/2 and g9/2 , taking 56 Ni
as an inert core. One advantage of such a model spaceis that it is free from the spurious center of mass motions. The largest M -scheme dimension of this model
space reaches about 13 billions, which is beyond thecurrent basis-size limitation in the conventional diagonalization method, and therefore, the MCSM can playa role. Considering the connection with the pf -shell,
it is more natural to take the pf + g9/2 space including
also the f7/2 orbits, which is in fact in a scope of our
future investigation.
In order to obtain an eﬀective interaction for thismodel space, we have carried out the similar ﬁtting
calculations as in the case of the pf -shell. Startingfrom a microscopic interaction,4) we have varied 32
linear combinations of Hamiltonian parameters (133
two-body matrix elements and four single-particle energies) by the least-squares ﬁt to the 310 experimental
data out of 69 nuclei with A = 63–96. In the latest
iteration, we have attained the rms error of 213 keV.
Since the closed 56 Ni core is severely broken3) in Ni
isotopes around N = 34 due to the strong protonneutron interaction, it is not practical to describe Ni
isotopes in the present model space. Keeping in mind
a future inclusion of f7/2 orbit in the model space, we
exclude the data of Ni isotopes for the ﬁt. Also, in thepresent model space, there are many nuclei in whichstrong E2 transitions among low-lying states are observed, suggesting large deformation. Such nuclei arefound in the middle of the model space, corresponding
∗1
∗2
∗3
∗4

to isotopes from Se to Zr around N ∼ Z line. Becauseof the missing f7/2 orbit and upper Nosc = 4 orbits
such as the d5/2 , the present model space is not suitable for the description of such states. We excluded
them from the data to be ﬁtted. Thus, our targets ofthe present approach are mainly: (1) Z ∼ 32 region,(2) N ∼ 50 region, and (3) Z ≥ 40 region.
As an example, the systematics of low-lying statesof Ge isotopes are shown in Fig. 1. We can ﬁnd reasonable agreement between the experimental data andthe shell-model results throughout the isotope chain.
However, the description becomes worse for N > 40,
suggesting the eﬀects of missing f7/2 orbit.

Fig. 1. Energy levels of yrast 2+ and 4+ states for Ge isotopes. The experimental data are shown by horizontal
bars, while symbols show shell-model values obtainedby a code MSHELL.5) Data are taken from Ref. 6.

References
1) T. Otsuka et al.: Phys. Rev. Lett. 81, 1588 (1998).
2) M. Honma et al.: RIKEN Accel. Prog. Rep. 33, 16(2000); RIKEN Accel. Prog. Rep. 34, 15 (2001); RIKEN
Accel. Prog. Rep. 35, 12 (2002); RIKEN Accel. Prog.
Rep. 36, 21 (2003); RIKEN Accel. Prog. Rep. 37, 17(2004).
3) M. Honma et al.: Phys. Rev. C 65, 061301(R) (2002);
Phys. Rev. C 69, 034335 (2004).
4) M. Hjorth-Jensen: private communications.
5) T. Mizusaki: RIKEN Accel. Prog. Rep. 33, 14 (2000).
6) Data extracted using the NNDC WorldWideWeb sitefrom the ENSDF database.

Center for Mathematical Sciences, University of Aizu
Department of Physics, University of Tokyo
Center for Nuclear Study, University of Tokyo
Institute of Natural Sciences, Senshu University

29

RIKEN Accel. Prog. Rep. 38 (2005)

Hartree-Fock calculation of three-dimensional nuclear rotation
Y. Hashimoto∗1 and T. Horibata∗2[NUCLEAR STRUCTURE, tilted axis rotation, wobbling motion]
A typical mode of collective motion of a deformed
nucleus is the uniform rotation about the shortest principal axis, where the moment of inertia is the largest.
In general, there are other classes of rotational motion: One is a mode in which the nucleus rotates aboutan axis which is not any of the principal axes, calledtilted axis rotation (TAR).1,2) Another is the nonuniform rotational motion called the wobbling motion inwhich the angular velocity is not uniform but timedependent and the rotational axis is tilted away fromthe principal axes.3,4) Recent experimental data support the existence of the wobbling motion.5)
Kerman and Onishi (referred to as KO)6) presented
a framework to study the general mode of rotationalmotion as wobbling motion with the use of HartreeFock (HF) calculation. Based on this framework, Horibata and Onishi (referred to as HO)1) found an intrinsic state corresponding to TAR as the Hartree-FockBogoliubov (HFB) solution. In the calculations performed by HO, the P+QQ model was used together
with a truncated single-particle space. Then the KO
theory was applied in the modern framework of HF
or HFB based on spatial mesh and density-dependent
local eﬀective interactions as the Skyrme force.
In this brief report, we present the numerical results
obtained by Hartree-Fock calculations with a simpliﬁed density-dependent local eﬀective interaction of therotational motion where the axis of rotation is tilted
away from the shortest principal axis.
The energy of the model Hamiltonian that we usedin the present calculation is given as




 
h̄2 2
(τ )
3
∇ ψj (x)ψ (τ ) j (x)∗ −E= d x2m
τ =p,n j+ a2 D(x)2 + a3 D(x)3

Fig. 1. Variation in energy against tilt angle for angularmomenta from j0 = 2 (crosses) to j0 = 6 (filled circles).



11+ D(x)VY (x) + Dp (x)Vc (x) ,
2
2

(1)

where VY (VC ) is the Yukawa (Coulomb) potential,
and a2 and a3 are parameters. D(x) and Dp (x) indicate the total nucleon density and proton density,
respectively. In this report, we show the results fora case with N = Z = 12. The pairing eﬀects are
neglected. As the numerical basis in the HF calculation, the Lagrange mesh is used.7) As explained in thepaper by HO, the HF equation is solved with six constraints, namely, three angular momenta, Jx  = jx ,
∗1
∗2

30

Jy  = jy and Jz  = jz , for a given set of (jx , jy , jz )and three principal axis conditions, yz = 0, zx = 0
and xy = 0.
The ground state is triaxially deformed. The shortest axis of the deformed density distribution is taken as
the x-axis, and the longest, the z-axis. The tilt angle
θ is deﬁned as jx = j0 cos θ, jy = 0 and jz = j0 sin θ
for a given angular momentum j0 . In Fig. 1, we show
the variation in energy E(j0 , θ) in Eq. (1) against thetilt angle θ for several angular momenta j0 . At theminimum point of each of the curves, the angular momentum vector j = (jx , jy = 0, jz ) is parallel to the
angular velocity vector ω = (ωx , ωy = 0, ωz ), indicating the possibility of TAR.1)
In Fig. 1, each of the curves for angular momenta
larger than j0 ∼ 4 becomes irregular at a point of thetilt angle. For the tilt angle greater than the value
at this point, the nucleus takes an almost axially symmetric shape and the cranked HF solution for the tilted
axis is not easy to ﬁnd numerically.
Because the pairing eﬀects are not considered in thepresent calculation and the eﬀective interaction is notrealistic, the results in Fig. 1 are preliminary. Reﬁnements of the numerical method are now in progress.

Institute of Physics, University of Tsukuba
Faculty of Software and Information Technology, Aomori
University

References
1) T. Horibata and N. Onishi: Nucl. Phys. A 596, 251(1996).
2) S. Frauendorf: Rev. Mod. Phys. 73, 463 (2001).
3) A. Bohr and B. R. Mottelson: Nuclear Structure, Vol. II(Benjamin, Reading, New York, 1975).
4) I. Hamamoto and G. B. Hagemann: Phys. Rev. C 67,
014319 (2003).
5) S. W. Ødegård et al.: Phys. Rev. Lett. 86, 5866 (2001).
6) A. K. Kerman and N. Onishi: Nucl. Phys. A 361, 179(1981).
7) D. Baye and P. H. Heenen: J. Phys. A 19, 2041 (1986).

RIKEN Accel. Prog. Rep. 38 (2005)

Symmetry in random matrix theory
N. Shimizu∗1 and T. Otsuka∗1,∗2[Nuclear Shell Model, Quantum Chaos]
Although quantum chaos has been studied for a longtime, the properties of the ground state have not been
known well, and its survey is a challenging topic. In
the nuclear shell model, Johnson et al. discovered the“J = 0 dominance” of the ground state provided bya random Hamiltonian matrix.1) The J = 0 dominance indicates that the ground-state spin (J) of eveneven nuclei obtained by a random Hamiltonian matrix favors zero. In the sd-shell with six neutrons, theground-state spin becomes J = 0 in the probabilityof 76% with randomly generated two-body matrix elements, whereas only 9.8% of the Hilbert space of six
neutrons in the sd-shell is J = 0.
After this discovery, many works have been performed to investigate the ground-state properties provided with the random interaction (e.g., see Ref. 2).
However, the origin of the J = 0 dominance is still unclear. We propose the following ansatz for describing
the J = 0 dominance.
• A certain type of random interaction mixes various states strongly in a chaotic manner without
preference, in the eigenstates of a many-body system.
• In this situation, maximum binding can beachieved by the wave function being invariant withrespect to the transformation of coordinates, because all orientations should be equal.
• The highest symmetries are then assigned to theground state; the distortion of the wave function
results in the loss of binding energy.
Concerning a rotational symmetry, the consequenceof this ansatz is the J = 0 dominance of the groundstate which is consistent with the work by Johnson
et al.1) In this report, we show two cases of the realization of other highest symmetries provided by random
interaction for the verification of this ansatz.
First, we show the isospin distribution of the groundstate in Table 1. The random interaction is provided
by a two-body random ensemble (TBRE),3) where twobody matrix elements of the Hamiltonian are random
numbers obeying the Gaussian distribution. The system consists of Nν neutrons and Nπ protons in theorbits d3/2 , d5/2 , and s1/2 .
Table 1 shows the probability that the isospin of theground state will be the lowest value (P (Tmin )) as compared to the ratio of the dimensions of the Tmin subspace to those of the entire Hilbert space (H. space).
∗1∗2

Department of Physics, University of Tokyo
Center for Nuclear Study, University of Tokyo

Table 1. Probability that the isospin of the ground state
will be the lowest value (P (Tmin )) as compared to theratio of the dimensions of the Hilbert space (H. space).
See the text for details.
(Nν , Nπ )P (Tmin ) (%)
H. space (%)(2,2) (2,4) (2,6) (4,4) (4,6) (6,6)
71.4 87.6 96.3 86.2 96.2 91.0
38.4 52.1 82.9 27.8 60.2 25.5

The highest symmetry state in the ansatz corresponds
to the lowest isospin state (Tmin ) in terms of the rotational transformation of the isospin space. We seethat the P (Tmin ) is much higher than the ratio of thedimensions of the Tmin subspace.
Second, the probability that the ground state will
have a positive parity (P (J + )) and the positive parity
state ratio in the Hilbert space (H. space) are shownin Table 2. The system consists of Nν neutrons in theorbits p3/2 , p1/2 , f5/2 , and g9/2 . The probability is obtained by 1000 runs of TBRE Hamiltonians. In thiscase, the highest symmetry state in the ansatz corresponds to the state with a positive parity. Although
the parity positive state ratio of the entire Hilbert
space is almost the same as the parity negative state
ratio, the probability that the ground state will havea positive parity is higher than 80%.
These results are shown to be consistent with ouransatz, because the ground state provided by random interaction is likely to have the highest symmetry
states, which correspond to the lowest isospin and positive parity states. You can see further discussion ofthis work in Ref. 3.
This work is a part of the RIKEN-CNS collaboration
project on large-scale nuclear structure calculation.
Table 2. Probability that the parity of the ground state
will be positive (P (J + )) as compared to the ratio ofthe dimensions of the Hilbert space (H. space). See thetext for details.
Nν
P (J + ) (%)
H. space (%)

2
81.6
44.2

4
86.4
52.1

6
81.0
50.4

8
82.6
50.1

10
84.4
50.0

References
1) C. W. Johnson, G. F. Bertsch, and D. J. Dean: Phys.
Rev. Lett. 80, 2749 (1998).
2) Y. M. Zhao, A. Arima, N. Shimizu, K. Ogawa, N.
Yoshinaga, and O. Scholten: Phys. Rev. C 70, 054322(2004).
3) N. Shimizu and T. Otsuka: AIP Conf. Proc. 726, 43(2004).

31

RIKEN Accel. Prog. Rep. 38 (2005)

Strange tribaryons as K̄-mediated dense nuclear systems
Y. Akaishi, T. Yamazaki, and A. Doté∗[strange tribaryon, kaonic nuclei, dense nuclei]
We discuss implications of recent discoveries of
strange tribaryons in 4 He(stopped-K − , p)S0 (3115)1)
and 4 He(stopped-K − , n) S1 (3140)2) in the frameworkof deeply bound K̄ nuclear states. The isospin structure of strange tribaryon system is shown in Fig. 1.
S1 (3140) corresponds to an originally predicted shrunk
T = 0 ppnK − ,3,4) whereas S0 (3115) can be identiﬁed
to T = 1 pnnK − , which is an isobaric analog state of
pppK − , also predicted before.5,6) In the T = 1 state,
the nuclear core is a non-existing (N N N )T =3/2 onewith a peculiar density distribution as shown in theﬁgure. We point out that the observed total binding
energies can be accounted for by including the relativistic eﬀect and by invoking a medium-enhanced K̄Ninteraction by 15% (see Fig. 2), which may occur as
an eﬀect of chiral symmetry restoration in such a highdensity nuclear medium. The experimental observation as a whole supports the predicted shrinkage ofK̄-mediated nuclear systems.
Fig. 2. Calculated K̄-core potentials, UK̄-core (r), for the
T = 0 ppnK − state in three cases: without shrinkage,with shrinkage with the original bare K̄N interaction
and with an enhanced bare K̄N interaction by 15%.
The relativistic eﬀects on the K̄-core binding energies(EK̄-core ) are indicated by arrows. Also shown is thenuclear core energy, ∆Ecore (r), with an average value(< ∆Ecore >).

References

Fig. 1. Spin-isospin structure of the strange tribaryon
system [(N N N )K̄]Q. The previously calculated(T ,T3 )nucleon-density contours and energy levels with EK
values are shown on top. The observed S0 (3115) andS1 (3140) are identiﬁed as the (T, T3 ) = (1, −1) and
T = 0 states, respectively.

∗

32

Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)1) T. Suzuki et al.: Phys. Lett. B 597, 263 (2004).
2) M. Iwasaki et al.: nucl-ex/0310018, submitted to Phys.
Lett. B.
3) Y. Akaishi and T. Yamazaki: Phys. Rev. C 65, 044005(2002).
4) A. Doté, H. Horiuchi, Y. Akaishi, and T. Yamazaki:
Phys. Lett. B 590, 51 (2004).
5) T. Yamazaki and Y. Akaishi: Phys. Lett. B 535, 70(2002).
6) A. Doté, H. Horiuchi, Y. Akaishi, and T. Yamazaki:
Phys. Rev. C 70, 044313 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Spin dependent nuclear structure functions†
I. C. Cloet,∗1 W. Bentz,∗2 and A. W. Thomas∗1[NUCLEAR STRUCTURE FUNCTIONS, Spin dependence, Eﬀective Quark Theories]
One of the most prominent phenomena in deep inelastic scattering of leptons oﬀ nuclei is the EMC eﬀect,
which concerns the spin-independent nuclear structure
functions.1) In a recent work,2) this eﬀect has beensuccessfully described in terms of the self consistentscalar and vector ﬁelds which couple to the quarks
inside the nucleons. Concerning the spin-dependent
nuclear structure functions, on the other hand, only
little is known about them both experimentally andtheoretically, except for very light nuclei. In this work
we will investigate the medium modiﬁcations of thespin-dependent structure functions of a nucleon boundin the nuclear medium, and present a simple model
calculation of the spin-dependent counter part of the
EMC ratio.
As an eﬀective chiral quark theory, we use theNambu-Jona-Lasinio model to describe the single nucleon as a bound state of a quark and a scalar diquark,and to describe nuclear matter in terms of self consistent scalar and vector mean ﬁelds which act on thequarks within the nucleons.3) It has been shown that
this approach describes the nuclear matter saturation
properties. By using the quark-diquark wave function
and the density dependent eﬀective masses obtained inthis model, we calculate the spin-dependent light-cone
momentum distributions of the quarks in the nuclear
medium by using the familiar convolution approach. In
principle, the spin-dependent smearing function representing the Fermi motion of the nucleons should be
calculated for a given valence nucleon orbit, but as aﬁrst step we employ the same function as for the spinindependent case. In the pure quark-scalar diquark
description, only the up quark contributes to the polarization of the proton. In order to describe also thedown quark contribution, one should include also theaxial vector diquark channel.
The results for the polarized up quark distribution(∆u(x)) at the saturation density of our nuclear matter equation of state are shown in Fig. 1 for the low
energy scale Q0 = 0.4 GeV. The dotted line shows the
distribution in a free nucleon, the dashed line shows
the result including the mean scalar ﬁeld, the dotteddashed line shows the result including the Fermi motion of nucleons, and the solid line also includes themean vector ﬁeld. It is clear from this ﬁgure that themean vector ﬁeld plays an important role to deplete
the distribution in the medium, which is reminiscent†∗1∗2

Condensed from an article by I. C. Cloet, W. Bentz, andA. W. Thomas, to be published.
Jeﬀerson Laboratories, USA
Department of Physics, Tokai University

Fig. 1. Medium modifications of the polarized up quark
distribution. For explanation of the lines, see text.

of the spin-independent case. Figure 2 shows the ratio of the in-medium ∆u(x) to the free nucleon value
at Q2 = 10 GeV2 , which represents a ﬁrst estimate of
the “spin-dependent EMC eﬀect” in this simple model.
It is interesting to observe that there is a plateau for
0.2 < x < 0.8 with an average value of about 0.7,
which is smaller than the well known spin-independent
EMC ratio. We can therefore expect that the medium
modiﬁcations are more important for the case of thespin-dependent structure functions than for the spinindependent ones.

Fig. 2. Ratio of the in-medium polarized up quark distribution to the free nucleon value.

References
1) M. Arneodo: Phys. Rep. 240, 240 (1994).
2) H. Mineo, W. Bentz, N. Ishii, A. W. Thomas, and K.
Yazaki: Nucl. Phys. A 735, 482 (2004).
3) W. Bentz and A. W. Thomas: Nucl. Phys. A 696, 138(2001).

33

RIKEN Accel. Prog. Rep. 38 (2005)

Chiral symmetry in light-cone field theory†
F. Lenz,∗1 M. Thies,∗1 K. Ohta,∗2 and K. Yazaki∗3[Hadron Physics, Chiral Symmetry, Light-Cone, Ward-Takahashi Identity]
We completed our work on chiral symmetry in lightcone quantization, a part of which had been reported
last year.1) This work was previously published,2) and
we report here its condensed form.
We study symmetry properties of systems with aspontaneously broken chiral symmetry in the lightcone formulation of field theories. The structure ofa vacuum, which is crucial for describing dynamical
symmetry breaking in a standard formulation, is kinematically determined in the light-cone formulation andis thus independent of symmetry realization. We attempt to understand how a dynamically broken phasecan be compatible with a trivial vacuum.
As in a standard field theory, we describe symmetry
properties from chiral Ward-Takahashi (WT) identities.3,4) Functional techniques are most convenient forsuch a purpose. We define a fermionic light-cone field
theory by a generating functional containing only theunconstrained degrees of freedom, i.e., with the “bad”
components of the spinors being eliminated. Such afermionic theory is nonlocal irrespective of dynamics.
It reflects the dependence of light-cone energy on the
inverse of light-cone momentum in the dispersion relation of a free particle. We note that the same dispersion relation determines the vacuum kinematically.
In the standard derivation of the relevant WT identities, one considers soft space-time-dependent modulations of global symmetry transformations.5) In asymmetry broken phase, these transformations generate soft excitations approaching zero energy excitations with increasing modulation wavelength, which
are called Nambu-Goldstone (NG) bosons.6,7) From
the WT identities, one identifies the creation operator of the NG bosons in the limit of vanishing momentum and one establishes a series of relations between

†
∗1
∗2
∗3

34

Condensed from the article in Phys. Rev. D 70, 025015(2004)
Institute for Theoretical Physics, University of Erlangen,Germany
Institute of Physics, University of Tokyo
College of Arts and Sciences, Tokyo Woman’s Christian University

composite NG bosons and the fundamental fermionic
degrees of freedom. In an application to the light-conetheory, this standard procedure fails due to the nonlocality of a light-cone Hamiltonian. The infinite nonlocality range induced by the inverse of light-cone momentum destroys the connection between soft modulations and low excitation energies. This is akin to the
suppression of NG particles in the presence of longrange interactions in gauge theories.
We demonstrate the failure of the standard procedure and show that the excitation of massive particles
is not suppressed in the limit of long- wavelength modulations. To adjust the procedure to the light-cone
Hamiltonian, we have to introduce nonlocal transformations of fermion fields. We carry out this by deriving
the general form of the light-cone WT identities and by
explicitly constructing the nonlocal symmetry transformations for various model field theories. We derive
Gell-Mann-Oakes-Renner-like relations8) and consider
the connection between a fermion propagator and thestructure function of the NG bosons.5)
References
1) F. Lenz, K. Ohta, M. Thies, and K. Yazaki: RIKEN
Accel. Prog. Rep. 36, 44 (2003).
2) F. Lenz, K. Ohta, M. Thies, and K. Yazaki: Phys. Rev.
D 70, 025015 (2004).
3) J. C. Ward: Phys. Rev. 78, 182 (1950).
4) Y. Takahashi: Nuovo Cimento 6, 371 (1957).
5) V. A. Miransky: Dynamical Symmetry Breaking in
Quantum Field Theory (World Scientific, Singapore,1993).
6) Y. Nambu: Phys. Rev. Lett. 4, 380 (1960).
7) J. Goldstone: Nuovo Cimento 19, 154 (1961).
8) M. Gell-Mann, R. J. Oakes, and B. Renner: Phys. Rev.
175, 2195 (1968).

RIKEN Accel. Prog. Rep. 38 (2005)

Tensor analyzing power for the d + α backward scattering
T. Uesaka,∗1 T. Ikeda,∗2 T. Kawabata,∗1 H. Okamura,∗3 K. Itoh,∗2 H. Sakai,∗4 K. Yako,∗4 T. Saito,∗4
H. Kuboki,∗4 M. Sasano,∗4 and K. Sekiguchi
4
He(d, 4 He)2 H reaction, D-state, tensor analyzing power
Short-range structures of light nuclei have a close
connection to the high-momentum behavior of nuclear
interactions which can not be fully described, for the
moment, neither by meson exchange theories nor by
non-perturbed quantum chromodynamics. Information on the short-range structure of light nuclei, especially spin-dependent one, is crucial to establish a better understanding of nuclear interactions. The d + α
backward scattering, which is the d + α elastic scattering at θ ∼ 180◦ , at intermediate energies can be a
candidate for a possible probe to the short-range structure of 4 He nucleus. Since the reaction in the backward
region is considered to be dominated by two-nucleon
transfer processes, the polarization observables as wellas the cross sections are expected to be sensitive to the4
He form factor of d-d or d-pn partition. In particular, tensor analyzing powers, Ayy and Axx , can provide an information on the D-state admixture in the
short-range region. In this report, the measurement of
the cross section and analyzing powers, Ay , Ayy , and
Axx , for the d + α backward scattering at the deuteronenergies of 140 MeV and 270 MeV is described. In addition to the d + α backward scattering, data for the4
He(d, 3 He)3 H reaction were also measured in the same
experimental conditions. The data are used to estimate the contribution from the sequential transfer of
two nucleons, d + α → 3 He + 3 H → α + d.
The experiment was carried out at the E4 experimental area of RIKEN Accelerator Research Facility.
A cryogenic 4 He gas target1) placed in the scatteringchamber was cooled down to ∼ 6 K. The target density and thickness were 8.1 mg/cm3 and 4.3 mg/cm2 ,respectively. Polarized deuteron beams with energies
of 140 and 270 MeV were used to bombard the target. α particles emitted at forward angles in the laboratory system were analyzed in the magnetic spectrograph SMART2) and detected with multiwire drift
chambers and three-layers of plastic scintillation counters located in the focal plane. Timing and pulse height
information of the plastic scintillation counters wasused to identify the particle. Momentum and scattering angle of the particle were reconstructed from theparticle trajctory determined from the timing data ofdrift chambers with a help of ion-optical parametersof SMART. The energy resolution was obtained to be
∗1
∗2
∗3
∗4

Center for Nuclear Study, University of Tokyo
Department of Physics, Saitama University
Tohoku University
Department of Physics, University of Tokyo

Fig. 1. Diﬀerntial cross section for the d + α elastic scattering at backward angles and at 270 MeV.

800 keV (FWHM), which is high enough to resolve thed + α backward events from pn − α events.
Figure 1 shows the preliminary results of the diﬀerential cross sections for the d + α backward scattering
at 270 MeV. The statistical uncertainty of each data
point is 1–5% depending on the angle and is smaller
than the symbol in the ﬁgure. The data obviously exhibits a 180◦ -peak distribution which is typical for the
nucleon transfer processes.
Tensor analyzing powers, Ayy and Axx are shownin Fig. 2. Both Ayy and Axx take large values of
Ayy = +0.2 ∼ +0.7 and Axx = −0.7 ∼ +0.2, respectively. Finite values of tensor analyzing powers
present a clear manifestation of the D-state admixture in 4 He at ﬁnite momenta. Detailed theoreticalanalysis to estimate contributions from the D-state ofdeuteron and the reaction mechanism will be evaluatedthrough analysis of the d + α elastic scattering and the4He(d, 3 He)3 H reactions.

Fig. 2. Tensor analyzing powers for the d + α elastic scattering at backward angles.

References
1) T. Ikeda et al.: CNS-REP-61, 86 (2004).
2) T. Ichihara et al.: Nucl. Phys. A 569, 287c (1994).

35

RIKEN Accel. Prog. Rep. 38 (2005)

Absolute calibration of proton polarization
via p
+4 He elastic scattering
S. Sakaguchi,∗1 T. Wakui,∗1 T. Uesaka,∗1 K. Itoh,∗2 T. Kawabata,∗1 H. Kuboki,∗3 Y. Maeda,∗1 H. Sakai,∗1,∗3
Y. Sasamoto,∗1 M. Sasano,∗3 K. Sekiguchi, K. Suda,∗1 Y. Takahashi,∗3 and K. Yako∗3[polarized solid proton target]
We have recently succeeded in developing a polarized
solid proton target which is distinctive in its applicability in a low magnetic ﬁeld of 80 mT and at a hightemperature of 100 K.1) The target was used, for theﬁrst time, in an experiment to measure the asymmetryof p + 6 He elastic scattering in 2003.2) During the scattering experiment, proton polarization was monitoredwith NMR. The NMR signal is usually calibrated using a known thermal equilibrium (TE) signal as a polarization standard. For our target, however, there isdiﬃculty in measuring the TE signal. The TE polarization of a proton is quite small in a low magnetic
ﬁeld of 80 mT and at a high temperature of 100 K. In
addition, the NMR sensitivity of our system is not sufﬁciently high, since the system is specialized to thescattering experiments. It is impractical to measure
the proton thermal equilibrium signal with the present
NMR system. We thus decided to use an alternative
method to determine the absolute value of the proton polarization by using a nuclear reaction. For thedetermination, we carried out a measurement of thespin-dependent asymmetry of p + 4 He elastic scattering, since polarization P is described asP =1 NL − NR,
A NL + NR(1)

where A is the analyzing power, and NL /NR are
left/right yields. Details of the experiment are reported in this paper.
The experiment was performed in the E3 experimental area at the RIKEN Accelerator Research Facility.
The energy and the typical intensity of the 4 He beam
were 80 MeV/nucleon and 200 kcps, respectively.
For the material of the target, we used a single crystal of naphthalene doped with 0.01 mol% pentacene.
The thickness of the target was 113 mg/cm2 . Protons
in the target were polarized by the cross-polarization
method.3) The target was operated at 88 mT and
100 K. Figure 1 shows the time development of the
NMR signal amplitude, which is proportional to proton polarization. Proton polarization ﬁrst increased in
the “up” direction from 0 to 29.2 h. The polarization
was once broken at 29.2 h, and increased in the opposite “down” direction from 37.8 to 52.0 h. Polarization
measurement for both cases of spin “up/down” was
∗1
∗2
∗3

36

Fig. 1. Time development of proton polarization measured
by pulsed NMR. The vertical axis denotes the NMR
signal amplitude, which is proportional to the proton
polarization. The origin of the horizontal axis denotes
the time when laser irradiation was started for the increase of polarization in the “up” direction.

Center for Nuclear Study, Graduate School of Science, University of Tokyo
Department of Physics, Saitama University
Department of Physics, University of Tokyo

carried out for the elimination of spurious asymmetry,
which will be described later. The target was irradiated with a 4 He beam from 14.8 to 29.2 h and from
41.5 to 52.0 h. A decrease in polarization was observed
after the beam irradiation started at 14.8 h. The small
polarization in the case of spin “down” might be dueto the beam irradiation eﬀect. Polarization measurement using elastic scattering was carried out from 17.0
to 29.2 h and from 41.5 to 52.0 h.
Figure 2 shows the schematic view of the experimental setup. For the detection of leading particles (mainly
4He), we used a forward-counter placed approximately
1 m downstream of the target. The forward-counter
consisted of a multiwired drift chamber (MWDC) andthree layers of plastic scintillation detectors placeddownstream of the MWDC. The MWDC was used todetermine the trajectory of the leading particles. The
plastic scintillation detectors were used to identify theleading particle by the standard ∆E-E method. The
thicknesses of the scintillators are 5 mm in the ﬁrst
layer and 30 mm in the other two layers.
For the detection of recoiled protons, a pair of
backward-counters was used. One was for the left-

Fig. 2. Schematic view of experimental setup. The distances from the target to plastic scintillators for 4 He
and protons are approximately 1 m and 180 mm, respectively.

hand event and the other was for the right-hand event.
Each counter consisted of two 5-mm strip silicon detectors (X-PSD, Y-PSD) and plastic scintillation detectors. The PSD had a 50 × 50 mm2 active area divided
into 10 strips on the front face. Two PSDs with an orthogonal strip direction located 120 mm and 140 mm
from the target determined the scattering angles of
the recoiled protons in both vertical and horizontal directions. The identiﬁcation of recoiled particles was
performed with the ∆E data from the PSDs and E
data from the plastic scintillation detectors. To discriminate background events, scattered 4 He particles
and recoiled protons were detected in coincidence.
For the elimination of spurious asymmetry resulting
from asymmetric geometry, we counted the numberof elastic scattering events with left and right detectors in both cases where the polarizations were up anddown. We then obtained yields as NL↑ , NR↑ , NL↓ , andNR↓ where indices L/R represent left/right and ↑/↓represent up/down proton polarizations, respectively.
The elimination of spurious asymmetry and derivationof the polarization were carried out using those yields
by a calculation method described in Ref. 4.
The p + 4 He elastic scattering events are clearly identiﬁed by the identiﬁcation of a proton and 4 He, andwith conditions of kinematical consistency. Diﬀerential cross sections are deduced for each strip of the
X-PSD from 38◦ to 70◦ in the center-of-mass system.

The results obtained in 5 strips are shown in Fig. 3.
From 44◦ to 56◦ , our results are consistent with thepreviously reported data5) obtained under an ordinary
kinematics condition. In the forwardmost strip, whichcorresponds to the angular range from 37.9◦ to 41.7◦ ,the obtained cross section is about half the previously
reported value. This is due to the fact that a number of the recoiled protons stop before reaching theplastic scintillators. Consequently, the corresponding
events are not taken into account in the present analysis where E data of the plastic scintillator is required.
Note that, in the angular range, energies of recoiled
protons are as low as < 10 MeV at the entrance ofthe detectors, owing to energy loss in the target material, cooling nitrogen gas, window foils and so on. In
the future analysis, the energy loss correlation between
X-PSD and Y-PSD is to be used for particle identiﬁcation. Those events can then be reliably used to obtain
the p+4 He elastic scattering yield. The proton polarization will be determined from the elastic scattering
yields for spin up/down.

Fig. 3. Diﬀerential cross sections of p+4 He elastic scattering. The open circles show the present data, and theclosed circles the previously reported data.5)

References
1) M. Hatano et al.: RIKEN Accel. Prog. Rep. 36, 48(2003).
2) M. Hatano et al.: RIKEN Accel. Prog. Rep. 37, 44(2004).
3) T. Wakui et al.: RIKEN Accel. Prog. Rep. 36, 171(2003).
4) G. G. Ohlsen: Rep. Prog. Phys. 35, 717 (1972).
5) H. Togawa et al.: RCNP Ann. Rep. 1987, 1.

37

RIKEN Accel. Prog. Rep. 38 (2005)

Breakup reactions of 11 Li
T. Nakamura, A. M. Vinodkumar,∗1 T. Sugimoto,∗1 N. Fukuda, Y. Kondo,∗1 M. Miura,∗1 N. Aoi, N. Imai,∗2
T. Kubo, T. Kobayashi,∗3 T. Gomi, A. Saito, H. Sakurai,∗4 S. Shimoura,∗5 D. Bazin,∗6 H. Hasegawa,∗7
H. Baba,∗7 T. Motobayashi, K. Watanabe,∗3 Y. X. Watanabe,∗2 T. Yakushiji,∗3 Y. Yanagisawa, K. Yoneda,∗6
and M. Ishihara[NUCLEAR REACTIONS: Coulomb Dissociation, Halo Nuclei]
Strong E1 excitation to the low-lying continuum(soft E1 excitation) is one of the characteristic features of halo nuclei. This excitation has been well understood for one-neutron halo nuclei, such as 11 Be and19
C, by the E1 direct breakup mechanism as shownin our previous 11 Be works using Coulomb dissociations.1–3) On the other hand, the soft E1 excitation for
the two-neutron halo case as in 11 Li is not well understood, mainly due to discrepancies among three previously obtained experimental results on the Coulomb
dissociation at MSU,4) RIKEN,5) and GSI.6)
We have thus studied the Coulomb dissociation of
11
Li on a Pb target at an incident energy of approximately 70 MeV/nucleon to obtain the data with muchhigher statistics and much less ambiguity caused bycrosstalk events in detecting two neutrons. Nuclear
breakup with a light target was also studied, partof which has already been reported.7) A secondary
beam of 11 Li was produced by fragmentation of a
100 MeV/nucleon primary 18 O beam in a thick Be production target and separated using the RIPS radioactive beam line at RIKEN. The 11 Li beam bombarded a
Pb target of thickness 346 mg/cm2 with an average energy of 70 MeV/nucleon. The momentum of the beam
ion was obtained by tracing the trajectory with two
PPAC’s and by measuring the time of flight (TOF)
using a thin plastic scintillator and an RF signal. The
outgoing particles, a 9 Li ion and two neutrons, were
emitted in a narrow kinematical cone at forward angles. The trajectory of the 9 Li ion was bent using alarge-gap dipole magnet, tracked with a drift chamber,and then the 9 Li ion hit a hodoscope. The momentumof the 9 Li ion was thus obtained using the tracking
information in combination with the TOF. The momentum of neutrons was obtained using the TOF andposition information at the neutron detector arrays,
which were composed of 54 rods of plastic scintillators arranged into two layers. The details of the experimental setup can be seen in the previous report.8)
The momentum vectors of outgoing particles were then
∗1
∗2
∗3
∗4
∗5
∗6
∗7

38

Department of Physics, Tokyo Institute of Technology
High Energy Accelerator Research Organization (KEK)
Department of Physics, Tohoku University
Department of Physics, University of Tokyo
Center for Nuclear Study, University of Tokyo
National Superconducting Cyclotron Laboratory, Michigan
State University, USA
Department of Physics, Rikkyo University

combined to extract the invariant mass of the excited
11
Li nuclei.
Figure 1 shows the preliminary spectrum of the relative energy (Erel ) of the three outgoing particles, 9 Li
and two neutrons. A large peak at Erel ∼ 0.5 MeV isobserved. The cross section amounts to 2.74 ± 0.07
(stat.) barns for Erel ≤ 3 MeV (preliminary). The
B(E1) strengths were obtained to be 1.5 ± 0.1 e2
fm2 for Erel ≤ 3 MeV using the conventional equivalent photon method. The observed B(E1) spectrum peaked at lower excitation energies with higher
strengths, compared with the results of the previous
experiments. Further analysis, such as on two neutron
correlations, is now in progress.

Fig. 1. Relative energy spectrum of the three outgoing particles (9 Li + n + n) in the breakup of 11 Li on Pb.

References
1) T. Nakamura et al.: Phys. Lett. B 331, 296 (1994).
2) N. Fukuda, T. Nakamura et al.: Phys. Rev. C 70,
054606 (2004).
3) T. Nakamura et al.: Phys. Rev. Lett 83, 1112 (1999).
4) K. Ieki et al.: Phys. Rev. Lett 70, 730 (1993).
5) S. Shimoura et al.: Phys. Lett. B 348, 29 (1995).
6) M. Zinser et al.: Nucl. Phys. A 619, 151 (1997).
7) T. Nakamura et al.: RIKEN Accel. Prog. Rep. 35, 57(2002).
8) A. M. Vinodkumar et al.: RIKEN Accel. Prog. Rep. 37,
50 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Coulomb and nuclear breakup of a halo nucleus 11 Be†
N. Fukuda, T. Nakamura,∗1 N. Aoi, N. Imai,∗2 M. Ishihara, T. Kobayashi,∗3 H. Iwasaki,∗4 T. Kubo,
A. Mengoni,∗5 M. Notani,∗6 H. Otsu,∗3 H. Sakurai,∗4 S. Shimoura,∗7 T. Teranishi,∗8 Y. X. Watanabe,∗2
and K. Yoneda∗9
NUCLEAR REACTIONS: Pb(11 Be, 10 Be n) X, C(11 Be, 10 Be n) X, Halo nuclei, Coulomb
breakup, Nuclear breakup
We have investigated the Coulomb and nuclear
breakup of 11 Be on Pb and C targets at energies
of 69 MeV/nucleon and 67 MeV/nucleon, respectively.
By measuring the momentum vectors of the incoming
11
Be ion, of the outgoing 10 Be ion, and the neutron
in coincidence, we have extracted the relative energy
spectra as well as the angular distributions of the scattering of the 10 Be + n c.m. system on both targets.
The obtained angular distribution of the 10 Be + nc.m. on Pb has been found to be well described by
the ﬁrst-order E1 Coulomb breakup mechanism, inparticular for the very forward angular regions corresponding to large impact parameters in the semiclassical point of view. The experimental relative energy
spectrum selected for b ≥ 30 fm (or θ ≤ 1.3◦ ) is in perfect agreement with the 1st-order pure E1 Coulomb
calculation with the direct breakup mechanism, leading to a spectroscopic factor for the halo conﬁguration+10
Be(0 ) ⊗ ν2s1/2 of 0.72 ± 0.04.
The E1 non-energy-weighted sum, corresponding to
the integrated B(E1) strength, has been compared to
the value calculated with the cluster sum rule, leading
to a root-mean-square distance of 5.77 ± 0.16 fm forthe neutron in its halo state. The energy-weighted
cluster sum rule has been applied to the present case.
The energy-weighted E1 strength has been found to be
70% ± 10% of the value calculated with this sum rule.
It is interesting to note that this value agrees with thevalue of α2 = 0.72(4).
The inelastic breakup scattering of 11 Be on a C target has been investigated experimentally. We have observed two peaks corresponding to the Ex = 1.78 MeV
and 3.41 MeV states. The angular distributions forthese states show L = 2 excitation patterns, leading
to their spin-parity assignments of J π = (3/2, 5/2)+ .
The amplitude of the angular distribution provided
the deformation lengths for these states as well. The
†
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8
∗9

energy levels and the transition densities have been
compared with those from shell model calculations forthe low-lying positive parity states of 11 Be in the psd model space with the WBT eﬀective interaction.
We have found that the energy levels and deformation lengths are rather well reproduced. The comparison with the shell model calculation also suggests
J π = 5/2+ and J π = 3/2+ as preferred assignments for
the Ex = 1.78 MeV and 3.41 MeV states, respectively.
The deformation lengths are also well reproduced by
the shell model calculation with Bernstein’s prescription and the conventional values of eﬀective charges.
The angular distributions have been investigatedfurther to elucidate the reaction mechanism. We havefound that the L = 1 Coulomb component is strong atvery forward angles in contrast with the L = 2 patternin the angular distribution around the 1.78 MeV resonance. In fact, the relative energy spectrum for θ ≤0.5◦ is well reproduced by the pure E1 direct breakup
model. This result shows that Coulomb breakup occurs at forward angles even on a light target such ascarbon.
Finally, we have estimated the nuclear breakup
and/or higher order eﬀects by subtracting the calculated pure E1 Coulomb component for the Pb target.
By making a comparison of the subtracted spectrumwith the C target, the scaling factor Γ of the nuclear
contribution for the Pb target to the C target is estimated. The scaling factor needed to reproduce thedata at Erel ≥ 2 MeV has been found to be Γ = 2.1(5),which is consistent with Serber-type models. Thisvalue is smaller than Γ = 5.4 extracted from data at
higher energies. This incident energy dependence canbe qualitatively explained in the eikonal picture.

Condensed from the article in Phys. Rev. C 70, 054606(2004)
Department of Physics, Tokyo Institute of Technology
High Energy Accelerator Research Organization (KEK)
Department of Physics, Tohoku University
Department of Physics, University of Tokyo
Applied Physics Division, Italian National Agency for New
Technologies, Energy and the Environment, Italy
Physics Division, Argonne National Laboratory, USA
Center for Nuclear Study, University of Tokyo
Department of Physics, Kyushu University
National Superconducting Cyclotron Laboratory, Michigan
State University, USA

39

RIKEN Accel. Prog. Rep. 38 (2005)

Coulomb and nuclear breakup of 14 Be
T. Sugimoto,∗1 T. Nakamura,∗1 N. Fukuda, M. Miura,∗1 Y. Kondo,∗1 N. Aoi, H. Baba,∗2 D. Bazin,∗3 T. Gomi,
H. Hasegawa,∗4 Y. Hashimoto,∗1 N. Imai,∗5 T. Kobayashi,∗6 T. Kubo, T. Motobayashi, M. Ohara,∗1 A. Saito,∗2
H. Sakurai,∗7 S. Shimoura,∗2 A. M. Vinodkumar,∗1 K. Watanabe,∗6 Y. X. Watanabe,∗5 T. Yakushiji,∗6
Y. Yanagisawa, K. Yoneda,∗3 and M. Ishihara

NUCLEAR REACTIONS: C(14 Be, 12 Be n), C, Pb(14 Be, 12 Be 2n), Coulomb breakup, Nuclear breakup
We studied the nuclear structure of two-neutron halo
nucleus 14 Be using Coulomb- and nuclear-breakup reactions. In the case of one-neutron halo nuclei such as
11
Be, the low-lying E1 strength, observed characteristically in the Coulomb breakup of halo nuclei, is well understood as being the direct-breakup mechanism. The
B(E1) distribution was used to extract a spectroscopic
factor of the halo conﬁguration of 11 Be.1,2) In the caseof the two-neutron halo, however, the excitation mechanism is not well understood due to the experimental
and theoretical diﬃculties. To study the excitation
mechanism, we performed an experiment on Coulomb
breakup of 14 Be. In addition, we performed a nuclearbreakup experiment to study the ﬁrst 2+ state, since
it is related to the deformation of 14 Be.
The experiment was performed at the RIPS beamline. The secondary 14 Be beam was produced by fragmentation of the 18 O primary beam at 100A MeV. The
secondary beam was identiﬁed event-by-event by thestandard Bρ-TOF-∆E method. The secondary lead22
and carbon target (346 mg/cm and 377 mg/cm , re14
spectively) were bombarded by Be with a central energy of 70A MeV. 14 Be was broken up into charged
particles and neutrons. The charged particles and neutrons were measured simultaneously. The experimental details are presented in a former report.3)
Figure 1 shows the relative-energy spectrum of the12
Be + 1n system measured with the carbon target.
The √relative-energy resolution is estimated as ∆Erel =0.25 Erel MeV. In the spectrum, a broad peak at
0.2 MeV is observed. Assuming the peak to be a 2s
continuum state, we ﬁtted the experimental data using
a theoretical model,4) where the peak energy is related
to the scattering length a (Epeak ≤ h̄2 /2µa2 ). The
ﬁtting parameter obtained (a = −4.7 fm) is consistent
with the previous work.5) Although another peak at
2.1 MeV was reported,5–7) no clear peak was observedin our data.
We also analyze three-body (12 Be+2n) decay events
∗1
∗2
∗3
∗4
∗5
∗6
∗7

40

Department of Physics, Tokyo Institute of Technology
Center for Nuclear Study, University of Tokyo
National Superconducting Cyclotron Laboratory, Michigan
State University, USA
Department of Physics, Rikkyo University
High Energy Accelerator Research Organization (KEK)
Department of Physics, Tohoku University
Department of Physics, University of Tokyo

Fig. 1. Relative-energy spectrum of 12 Be + 1n system.

in the Coulomb breakup. To eliminate crosstalk eventsin the neutron counters, we developed a new algorithm
which enables us to reject more than 95% of crosstalkevents. Figure 2 shows the relative-energy spectrum of
the 12 Be + 2n system measured with the lead target.
The √estimated relative-energy resolution was ∆Erel =0.38 Erel MeV. Further analysis is in progress.

Fig. 2. Preliminary result of the relative-energy spectrumof 12 Be + 2n system.

References
1) T. Nakamura et al.: Phys. Lett. B 331, 296 (1994).
2) N. Fukuda et al.: Phys. Rev. C 70, 054606 (2004).
3) T. Sugimoto et al.: RIKEN Accel. Prog. Rep. 37, 59(2004).
4) G. F. Bertsch et al.: Phys. Rev. C 57, 1366 (1998).
5) M. Thoennessen et al.: Phys. Rev. C 63, 014308 (2000).
6) A. V. Belozyorov et al.: Nucl. Phys. A 636, 419 (1998).
7) J. L. Lecouey: Few-Body Systems 34, 21 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Lifetime of the first excited state of 12 Be
N. Imai, N. Aoi, H. J. Ong,∗1 H. Sakurai,∗1 K. Demichi,∗2 H. Kawasaki,∗2 H. Baba,∗2 Zs. Dombrádi,∗3 Z. Elekes,
N. Fukuda, Zs. Fülöp,∗3 A. Gelberg,∗4 T. Gomi,∗2 H. Hasegawa,∗2 K. Ishikawa,∗6 H. Iwasaki,∗5 E. Kaneko,∗2
S. Kanno,∗2 T. Kishida, Y. Kondo,∗6 T. Kubo, K. Kurita,∗2 S. Michimasa,∗5 T. Minemura, M. Miura,∗6
T. Motobayashi, T. Nakamura,∗6 M. Notani,∗3 T. K. Onishi,∗1 A. Saito,∗2 S. Shimoura,∗5 T. Sugimoto,∗6
M.K. Suzuki,∗1 E. Takeshita,∗2 S. Takeuchi, M. Tamaki,∗5 K. Yoneda, H. Watanabe, and M. IshiharaDoppler-shift attenuation method, 197 Au(12 Be, 12 Be∗ )197 Au E=40.3 MeV/u
We applied the Doppler-shift attenuation method(DSAM)1) to measure the lifetime of the ﬁrst excited
122+
Be in ﬂight. This
1 state located at 2.10 MeV ofis the ﬁrst application of DSAM to the intermediateenergy RI beam. The lifetime is inversely proportional
to the B(E2) value. To measure B(E2) of unstable nuclei, the Coulomb excitation method at the intermediate energy has been applied. However, this technique
is not suitable for small Z nuclei since the nuclear excitation competes with the Coulomb excitation. In orderto determine B(E2) of 12 Be, we adopted DSAM, which
has been used with thin targets where energy losses ofthe beams are negligible.
In the present experiment, a thick target was used
so that the velocity of the 12 Be beam was degradedby as much as 20% in the target. The target also
plays a role in exciting the beam to the 2+
1 state. Dueto the change in beam velocity, the Doppler-shifted
de-excitation γ-ray energy was spread over a certain
region. The energy of the γ-rays emitted inside thetarget was distributed continuously, while that of γrays emitted outside was constant since the excitednucleus no longer changed its velocity. In the energy
spectrum, one can distinguish the γ-rays emitted inside
the target from those emitted outside. The ratio ofthe γ-ray yield from inside the target to that from theoutside depends on the lifetime. Hence, measurementof the γ-ray energy spectrum allows one to determine
the lifetime.
A radioactive beam of 12 Be was produced by the
projectile fragmentation of a 100 MeV/u 18 O beamwith a 1850 mg/cm2 thick Be target. The 12 Be beams
were separated by the RIPS beam line2) and bombarded on a 1930 mg/cm2 thick Au target. At theﬁnal focal plane of RIPS, the energies of the beams
were 40.3 MeV/u. The typical secondary beam intensity was 400 kHz. The scattering angle was measured
using three parallel-plate avalanche counters, two of
which were located upstream and the third one downstream of the target. Identiﬁcation of the scatteredparticle was carried out using a plastic scintillator ho∗1
∗2
∗3
∗4
∗5
∗6

Department of Physics, University of Tokyo
Department of Physics, Rikkyo University
ATOMKI, Hungary
University of Köln, Germany
Center for Nuclear Study, University of Tokyo
Department of Physics, Tokyo Institute of Technology

Fig. 1. Obtained energy spectrum of γ-rays. A broad peak+around 1.7 MeV corresponds to the 2+
1 → 0g.s. transition in 12 Be.

doscope. It consisted of a 2-mm-thick ∆E plane anda 5-mm-thick E plane. The de-excitation γ-rays fromthe inelastically excited 12 Be were detected using fourclover Ge detectors (Clovers) manufactured by ORTEC. Each Clover was located 30 cm upstream of thetarget at 150 degrees with respect to the beam direction.
The projectile fragmentation reaction also produced
the isomeric 0+ state at 2.24 MeV in 12 Be, which partly
3)
We alsodecays to the ground state via the 2+
1 state.
measured the γ-rays without the target in order toestimate the eﬀect of the cascade transition from theisomeric state. The energy spectrum measured without the target was subtracted from that measured withthe target. The resultant spectrum is shown in Fig. 1.
The lifetime will be determined by comparison of themeasured spectrum with that of the simulation. The
simulated energy spectrum was obtained by a Monte
Carlo method. In the simulation, we took into accountthe geometry, the measured beam proﬁle, and the angular distribution of the γ-rays. Further analysis is inprogress.
References
1) S. Devons et al.: Proc. Phys. Soc. A 68, 18 (1955).
2) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
3) S. Shimoura et al.: Phys. Lett. B 560, 31 (2003).

41

RIKEN Accel. Prog. Rep. 38 (2005)

In-beam γ-ray spectroscopy of neutron-rich boron isotopes 15 B and17
B via inelastic scattering on 12 C
Y. Kondo,∗1 T. Nakamura,∗1 N. Aoi, H. Baba,∗2 D. Bazin,∗3 N. Fukuda, T. Gomi, H. Hasegawa,∗4 N. Imai,∗5
M. Ishihara, T. Kobayashi,∗6 T. Kubo, M. Miura,∗1 T. Motobayashi, A. Saito,∗2 H. Sakurai,∗7 S. Shimoura,∗2
T. Sugimoto,∗1 K. Watanabe,∗6 Y. X. Watanabe,∗5 T. Yakushiji,∗6 Y. Yanagisawa, and K. Yoneda∗3

NUCLEAR REACTIONS: C(15 B,15 B∗ ), C(17 B,17 B∗ ), in-beam γ-ray spectroscopy
We have observed a new γ transition in 17 B andknown two transitions in 15 B using in-beam γ-ray spectroscopy with inelastic scattering on 12 C.
The experiment was performed at the RIKEN Accelerator Research Facility using the in-ﬂight radioactiveisotope beam separator, RIPS.1) A 22 Ne beam at
110 MeV/nucleon bombarded a primary Be target of
1.1 g/cm2 thickness to produce the secondary 15 B
and 17 B beams. The secondary carbon target of
377 mg/cm2 thickness was placed at the third focal
plane (F3). The average kinetic energies of the 15 B
and 17 B beams were 72 MeV/nucleon in the center of
the target. The position and angle of the incident
beam at the secondary target were measured using
two parallel-plate avalanche counters (PPACs). Deexcitation γ rays were detected using about a half-setof the DALI system,2) composed of thirty-six blocks
of NaI(Tl) scintillators surrounding the secondary target. The outgoing boron isotopes were analyzed usinga magnetic spectrometer equipped with a drift chamber and a plastic scintillator hodoscope. The particle
identiﬁcation of the outgoing boron isotopes was performed by combining the ∆E and TOF informationfrom the hodoscope with the magnetic rigidity information from the drift chamber.
The observed γ transition in 17 B has been assigned
as the decay from the ﬁrst excited state at Ex =1.07 ± 0.01 MeV to the ground state. For 15 B, wehave observed two γ transitions, which are assigned
as a cascade decay from the second excited state(Ex = 2.71 MeV) to the ground state via the ﬁrst excited state (Ex = 1.30 MeV), using a γ-γ coincidence
analysis and by comparing the two observed γ-ray energies with those obtained from a recent study using
a fragmentation reaction.3) With the help of DWBA
analysis the angular distributions of inelastically scattered 15 B and 17 B isotopes have been found to exhibit∆Lπ = 2+ characteristics.
The deformation lengths for the transitions havebeen deduced to be 1.20 ± 0.08 fm for 17 B and 1.17 ±
∗1
∗2
∗3
∗4
∗5
∗6
∗7

42

Tokyo Institute of Technology
Center for Nuclear Study, University of Tokyo
National Superconducting Cyclotron Laboratory, Michigan
State University, USA
Rikkyo University
High Energy Accelerator Research Organization (KEK)
Tohoku University
University of Tokyo

0.12 fm for 15 B using diﬀerential cross sections analyzed with the ECIS code. These values are compared with calculated deformation lengths using theshell model. Figure 1 shows the comparison of theexperimental deformation lengths with the calculated
ones as a function of the neutron eﬀective charge enwith a ﬁxed proton eﬀective charge of ep = 1.3e. The
comparison clearly indicates en ≈ 0, which is diﬀerent from the conventional values of eﬀective charges
ep = 1.3e and en = 0.5e in sd -shell region.4) The
measurements of the Q moment for 15 B5) and 17 B6)indicated the quenching of the neutron eﬀective charge
for these neutron-rich boron isotopes.

Fig. 1. Dependence of deformation length δ on neutroneﬀective charge en of 17 B (top) and 15 B (bottom).
Hatched zones indicate experimental values. Solid anddotted lines indicate shell model calculation using PSDWBT and PSDMK interactions, respectively.

References
1) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
2) T. Motobayashi et al.: Phys. Lett. B 346, 9 (1995).
3) M. Stanoiu et al.: Eur. Phys. J. A 22, 5 (2004).
4) B. A. Brown and B. H. Wildenthal.: Ann. Rev. Nucl.
Sci. 38, 29 (1988).
5) H. Izumi et al.: Phys. Lett. B 366, 51 (1996).
6) H. Ogawa et al.: Eur. Phys. J. A 13, 81 (2002).

RIKEN Accel. Prog. Rep. 38 (2005)16 †Anomalously hindered E2 strength B(E2; 2+ → 0+Cg.s. ) in
N. Imai, H. J. Ong,∗1 N. Aoi, H. Sakurai,∗1 K. Demichi,∗2 H. Kawasaki,∗2 H. Baba,∗2 Zs. Dombrádi,∗3
Z. Elekes,∗3 N. Fukuda, Zs. Fülöp,∗3 A. Gelberg,∗4 T. Gomi,∗2 H. Hasegawa,∗2 K. Ishikawa,∗5 H. Iwasaki,∗6
E. Kaneko,∗2 S. Kanno,∗2 T. Kishida, Y. Kondo,∗5 T. Kubo, K. Kurita,∗2 S. Michimasa,∗6 T. Minemura,∗3
M. Miura,∗5 T. Motobayashi, T. Nakamura,∗5 M. Notani,∗3 T. K. Onishi,∗1 A. Saito,∗2 S. Shimoura,∗6
T. Sugimoto,∗5 M. K. Suzuki,∗1 E. Takeshita,∗2 S. Takeuchi, M. Tamaki,∗6 K. Yoneda,∗3
H. Watanabe,∗3 and M. Ishihara

NUCLEAR REACTIONS: 9 Be(16 C, 16 C∗ )9 Be E = 34.6 MeV/u; RSM
In a recent paper, we reported an anomalously small
B(E2) value of 16 C. This B(E2) value was determinedby the lifetime measurement of the ﬁrst excited statein 16 C.1) The lifetime τ is inversely proportional to theB(E2) value of the nucleus. To measure τ , we adopted
the recoil shadow method (RSM).2) This is the ﬁrst
application of the RSM to the τ measurement of theexcited state of the radioactive-isotope (RI) beam. In
the RSM, the emission point of the de-excitation γ
ray is located and the γ-ray intensity is recorded asa function of the ﬂight distance of the de-exciting nucleus. By utilizing an intermediate-energy RI beam,
the ﬂight velocity of the de-exciting nucleus is close
to half the light velocity even after the secondary reaction. With such a high velocity, the ﬂight distanceat τ of 100 ps corresponds to a macroscopic length ofabout 1.7 cm. The present RSM provides a wide range
of applications, extending to τ ≈ 20 ps.
A 16 C beam was produced by the projectile fragmentation of a 100 MeV/u 18 O beam with a thick1850 mg/cm2 Be target. The 16 C beam was separated
by the RIPS beam line3) and bombarded onto a thick
370 mg/cm2 Be target. In the middle of the target,
the energy of the beam was 34.6 MeV/u. The typicalsecondary beam intensity was 200 kHz.
The de-excitation γ rays from the inelastically excited 16 C nuclei were detected by an array of thirtytwo NaI(Tl) detectors. The array was divided into
two rings, R1 and R2. R1 (R2) was composed of 14(18) NaI(Tl) detectors and placed at 121 (102) degrees
from the center of the target position with respect tothe beam axis. To implement the RSM concept, weplaced a lead slab of 5 cm thickness immediately downstream of R2. The slab had a columnar hole with adiameter of 5 cm at the center, where the beam passed
through. The upstream surface of the slab was deﬁned
as z = 0.0 cm. The target was placed at z = 0.0 cm.
Due to the screening eﬀect of this slab, the eﬀective
†
∗1
∗2
∗3
∗4
∗5
∗6

γ-ray eﬃciencies of R1 and R2 are diﬀerent. The magnitude of the diﬀerence depends on the point of γ-ray
emission along the beam axis. Thus, τ can be deduced
from the γ-ray yield ratio (R1/R2).
The measurement was also performed with anothertarget position, z = 1.0 cm, to verify the deduced τ .
The τ value was determined by comparing of the measured R1/R2 ratio with the simulated ratios as a function of τ . The simulation was carried out by the Monte
Carlo method considering the measured emittance ofthe beams, scattering angles, and the calculated angular distribution of de-excitation γ rays. From theoverlapped regions of the experimental R1/R2 ratio
and the simulation, the τ values were determined tobe 92 ± 22 ps and 63 ± 17 ps for the data obtainedat the two target positions. As the ﬁnal value, we
adopted the weighted average of these two values. The
uncertainty mentioned above is attributed to the statistical error. By incorporating the systematic error,
which was mainly derived from the geometrical uncertainty of 1 mm, we determined τ = 77 ± 14(stat)±19(sys) ps. The central value of τ corresponds toB(E2) = 0.63 e2 fm4 or 0.26 Weisskopf units.
This B(E2) value is an order of magnitude smaller
than that obtained using an empirical formula based on
the homogeneous quantum liquid drop model.4) Considering the fact that the model reproduces the experimental B(E2) value of even-even nuclei with ±50%
discrepancy except for a few nuclei, the present large
diﬀerence from the model indicates an anomalous 16 C
structure.
References
1) N. Imai et al.: Phys. Rev. Lett. 92, 06251 (2004).
2) H. Backe et al.: Z. Phys. A 285, 159 (1978).
3) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
4) S. Raman et al.: At. Data Nucl. Data Tables 78, 1(2001).

Condensed from the article in Phys. Rev. Lett 92, 062501(2004)
Department of Physics, University of Tokyo
Department of Physics, Rikkyo University
ATOMKI, Hungary
University of Köln, Germany
Department of Physics, Tokyo Institute of Technology
Center for Nuclear Study, University of Tokyo

43

RIKEN Accel. Prog. Rep. 38 (2005)

18
Lifetime measurement of 2+C
1 state in
H. J. Ong,∗1 N. Imai, D. Suzuki,∗1 T. Nakao,∗1 H. Iwasaki,∗1 H. Sakurai,∗1 T. K. Onishi,∗1 M. K. Suzuki,∗1
S. Ota,∗2 S. Takeuchi, Y. Togano,∗3 Y. Kondo,∗4 N. Aoi, H. Baba,∗5 S. Bishop, J. Cook,∗6 Y. Ichikawa,∗1
M. Ishihara, T. Kubo, K. Kurita,∗3 T. Motobayashi, T. Nakamura,∗4 T. Okumura,∗4 and Y. Yanagisawa

NUCLEAR REACTIONS: 9 Be(18 C,18 C)9 Be, lifetime measurement, MRSM
The measurement of the reduced E2 transition probability from the ﬁrst excited 2+
1 state to the ground
)
state
B(E2)
in
an
even-evennucleus is an im(0+g.s.
portant tool for studying proton collectivity. Recently,
anomalously small B(E2) has been reported for theneutron-rich 16 C nucleus.1) The result indicates a surpressed proton contribution to the transition strength.
Extended studies on other neighboring nuclei such as
18
C may be helpful in understanding this exotic phenomenon.
We have performed an experiment using a modiﬁed
recoil shadow method (RSM)1) to measure the lifetime
18
C. The mechanism of γ-ray emisof the 2+
1 state insion is governed by the electromagnetic theory and thelifetime of a γ-ray-emitting nuclear state is inversely
proportional to B(E2). Hence, the lifetime measurement is a direct method of determining B(E2).
The experiment was performed at the RIKEN Accelerator Research Facility. A secondary beam of18
C was obtained in a fragmentation reaction using
a 110-MeV/nucleon 22 Ne beam with an intensity of
150 pnA incident on a 924-mg/cm2 9 Be target. The
secondary beams, consisting of 18 C, 17 C and 17 B, wereseparated with the RIKEN Projectile-fragment Separator (RIPS).2) The total beam intensity of the secondary beams was approximately 50 kcps at the ﬁnal
focal plane (F3). The time-of-ﬂight (TOF) of the secondary beams between the second focal plane (F2)and F3 were measured using two 1-mm-thick plastic
scintillators (PLs) placed at F2 and F3. The energyof the secondary beams deposited in the PLs (∆E)
was also measured. Particle identiﬁcation was performed by means of the TOF-∆E method. The purity of the 18 C beam was approximately 88%. The energy of the 18 C beam at F3 was deduced to be about
80 MeV/nucleon from the TOF information. A 370mg-thick secondary Be target was placed 1.5 m downstream of the PL at F3 to excite the 18 C nuclei.
Scattered particles were detected using a plastic
scintillatorhodoscope placed 4 m downstream of the

∗1
∗2
∗3
∗4
∗5
∗6

44

Department of Physics, University of Tokyo
Department of Physics, Kyoto University
Department of Physics, Rikkyo University
Tokyo Institute of Technology
Center for Nuclear Study, University of Tokyo
National Superconducting Cyclotron Laboratory, Michigan
State University, USA

secondary target. The hodoscope, which was mounted
in a vacuum chamber, consisted of thirteen 5-mm-thick∆E- and sixteen 60-mm-thick E- plastic scintillators.
The ∆E and E counters were set perpendicular toeach other, dividing the hodoscope into 13 × 16 segments. The position information obtained from thesegmentation of the hodoscope was used to determine
the scattering angle. The TOF between the secondary
target and the hodoscope was measured using the timing information of the hodoscope and that of the PL
at F3. The 18 C nuclei were stopped in the E counters. Particle identiﬁcation of the scattered particles
was performed by the TOF-∆E and TOF-E methods.
To implement the MRS method, we placed a thick
γ-ray shield around the target. The shield was a 5-cmthick lead slab with an outer frame of 24 × 24 cm2 andan inner hole of 5.4 cmφ. The de-excitation γ-rays weredetected in coincidence with the scattered 18 C using a
modiﬁed DALI2 detector array.3) The modiﬁed DALI2
consisted of 150 NaI(Tl) scintillators, which were divided into thirteen layers surrounding the target. Depending on the lifetime, the detection eﬃciency of theγ rays varies in each layer due to the presence of thelead shield. Measurements were also performed without the lead slab to reduce the systematic error due tothe geometrical ambiguity of DALI2.
By comparing the measured full-energy peak yields
in each layer with those obtained from GEANT sim18
C can beulations,4) the lifetime of the 2+
1 state indetermined. Data analysis is in progress.
References
1) N. Imai et al.: Phys. Rev. Lett. 92, 062501 (2004).
2) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
3) S. Takeuchi et al.: RIKEN Accel. Prog. Rep. 36, 148(2003).
4) GEANT3: Detector Description and Simulation Tool
(CERN, Geneva, 1993).

RIKEN Accel. Prog. Rep. 38 (2005)

Low-lying excited states of 17 C and 19 C
Z. Elekes,∗1 Zs. Dombrádi,∗1 R. Kanungo, H. Baba,∗2 Zs. Fülöp,∗1 J. Gibelin,∗3 Á. Horváth,∗4 E. Ideguchi,∗5
Y. Ichikawa,∗5 N. Iwasa,∗6 H. Iwasaki,∗5 S. Kanno,∗2 S. Kawai,∗2 Y. Kondo,∗2 T. Motobayashi, M. Notani,∗5
T. Ohnishi,∗5 A. Ozawa, H. Sakurai,∗5 S. Shimoura,∗5 T. Suzuki,∗2 E. Takeshita,∗2 S. Takeuchi, I. Tanihata,∗7
Y. Togano,∗2 C. Wu,∗8 Y. Yamaguchi,∗2 Y. Yanagisawa, A. Yoshida, and K. Yoshida
NUCLEAR STRUCTURE, Unstable nuclei, proton inelastic scattering, 17,19 C, bound excited states
Theoretical calculations predict two low-lying excited states of both 17 C and 19 C,1–3) but only one
excited state has been found in 17 C.4,5) Recently, indications of two γ transitions of 17 C have been reported,6) suggesting that both predicted excited states
are bound in 17 C. In addition, a γ peak in 19 C wasalso observed.6) To obtain more information on the
excited states in neutron rich odd carbon nuclei wehave studied them by the (p,p γ) process in inverse
kinematics. The experiment was carried out at the
RIKEN radioactive isotope separator RIPS.7) A 22 Ne
primary beam of 100 pnA intensity and 110 A·MeV energy hits a 9 Be production target of 0.8 cm thickness.
For optimizing the 19 C beam, the secondary cocktail
beam included 20% 19 C and 25% 17 B. By tuning the17
C beam, practically 100% purity could be achieved.
On an event-by-event basis, the identification of theincoming beam was performed by energy-loss, timeof-flight (TOF) and magnetic rigidity (Bρ) measurements. The secondary beam bombarded a liquid hydrogen target of 3 cm diameter.8) The DALI2 setup9)
surrounded the liquid hydrogen target to detect deexcited γ rays. A silicon telescope with layers of 0.5, 2
and 2 mm thicknesses was inserted in air atmosphereto identify scattered particles. To produce γ ray spectra, one fold events in the NaI(Tl) array were selected(Fig. 1). In the (a) panel, two peaks are clearly visible
at 72(4) and 197(6) keV which can be associated withthe prompt decays of excited states of 19 C. Figure 1 (b)shows two distinct peaks at 210(4) and 331(6) keV confirming two low-lying excited states of 17 C. In the (c)panel of the 1 H(17 C,17 C) reaction, the higher energy
peak is clearly visible, while the 210 keV peak is very
faint, if it exists at all, and is situated on the Compton background of the 331 keV peak. The counting
statistics in Fig. 1 (b) allowed us to perform a γ-γ coincidence analysis, which showed that the two observed
transitions of 17 C are not in coincidence. The analyses of the spectra and the cross sections are now inprogress.
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8

Insitute of Nuclear Research, ATOMKI, Hungary
Rikkyo University
Institut de Physique Nucléaire, FranceEötvös Lóránd University, Hungary
University of Tokyo
Tohoku University
Argonne National Laboratory, USA
Peking University, China

Fig. 1. Doppler-corrected spectra of γ rays emerging from1
H(19 C,19 C) (a), 1 H(19 F,17 C) (b), and 1 H(17 C,17 C) (c)reactions.

References
1) P. Descouvemont et al.: Nucl. Phys. A 675, 559 (2000).
2) V. Maddalena et al.: Phys. Rev. C 63, 024613 (2001).
3) R. Fujimoto: Ph.D. Thesis, University of Tokyo (2003).
4) L. K. Fifield et al.: Nucl. Phys. A 383, 505 (2000).
5) H. G. Bohlen et al.: Nucl. Phys. A 738, 333 (2004).
6) M. Stanoiu et al.: Eur. Phys. J. A 20, 95 (2004).
7) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
8) H. Akiyoshi et al.: RIKEN Accel. Prog. Rep. 32, 167(1999).
9) H. Hasegawa et al.: RIKEN Accel. Prog. Rep. 35, 169(2002).

45

RIKEN Accel. Prog. Rep. 38 (2005)

Decoupling of valence neutrons from the core in 16 C†
Z. Elekes,∗1 Zs. Dombrádi,∗1 A. Krasznahorkay,∗1 H. Baba,∗2 M. Csatlós,∗1 L. Csige,∗1 N. Fukuda, Zs. Fülöp,∗1
Z. Gácsi,∗1 J. Gulyás,∗1 N. Iwasa,∗3 H. Kinugawa,∗2 S. Kubono,∗4 M. Kurokawa, X. Liu, S. Michimasa,
T. Minemura,∗4 T. Motobayashi, A. Ozawa,∗5 A. Saito,∗4 S. Shimoura,∗4 S. Takeuchi, I. Tanihata,∗6 P. Thirolf,∗7
Y. Yanagisawa, and K. Yoshida
NUCLEAR STRUCTURE, Unstable nuclei, 16 C deformation
Recent calculations1) have suggested diﬀerent deformations for proton and neutron distributions in carbon isotopes. We applied the Coulomb-nuclear interference method to study proton and neutron contribution to the excitation of the ﬁrst 2+ state. The experiment was carried out in RIKEN. The 16 C beamwith 52.7 A· MeV at 4·105 particles/s was transmitted
to a 208 Pb target of 50 mg/cm2 thickness. The scattered particles were identiﬁed using a plastic scintillator hodoscope. For tracking the beam, four parallel
plate avalanche counters (PPAC’s) were used. The
angular resolution was 0.28 ◦ at 1σ. The de-exciting
γ-rays in coincidence with the 16 C particles were detected using an array of 68 NaI(Tl) scintillator detectors. The resulting angular distribution is showed
the minimum from the Coulomb-nuclear interference
at approximately 2.6◦ (Fig. 1). For the analysis of
the angular distribution, we used the coupled chan-

Fig. 1. Diﬀerential cross sections for the inelastic scatter16
ing exciting the 2+
C. The thick solid line
1 state inrepresent the best ﬁt with ECIS calculation which wassmoothed by the angular resolution of the experimental
setup (thin solid line: Coulomb part, dash-dotted line:
nuclear part). Dashed line is plotted with δM /δC = 0.67
local minimum value.
†
∗1
∗2
∗3
∗4
∗5
∗6
∗7

46

Condensed from the article in Phys. Lett. B 599, 17 (2004)
Institute of Nuclear Research, ATOMKI, Hungary
Rikkyo University
Tohoku University
University of Tokyo
University of Tsukuba
Argonne National Laboratory, USA
Ludwig-Maximilians-Universität, Germanynel code ECIS95.2) The optical model parameters weretaken from Ref. 3. The standard collective form factors were applied. Two parameters for the coupling
potential, the “Coulomb deformation” length δC andthe “matter deformation” length δM , characterizing respectively the Coulomb and nuclear interactions between the target and projectile, have been determinedby a χ2 -minimization analysis. Two χ2 -minima can befound at δM /δC = 0.67 and δM /δC = 3.1 with reduced
χ2 = 1.6. The resultant δM and δC are connected to
the neutron and proton transition matrix elements Mn
and Mp via the Bernstein formula.4) The deduced ratio
is Mn /Mp = 7.6 ± 1.7. The proton matrix element corresponds to an electromagnetic transition probabilityof B(E2) = 0.28 ± 0.06 Weisskopf units (W.u.), while
the neutron matrix element is slightly higher than the
single-particle matrix element. Our B(E2) being signiﬁcantly less than 1 W.u. is consistent with the result of a recent direct lifetime measurement, which
gives B(E2) = 0.26 ± 0.05 W.u.,5) and is the smallest transition probability ever observed, while the deduced Mn /Mp ratio is the highest thus far. Our experimental results clearly show that a very small proton
deformation, or more strictly a very small amount of
16
C.
proton excitation, contributes to the 2+
1 state in
The excitation is dominated by neutron transitions.
In a simple shell-model picture (two valence neutrons+14 C core), we estimated the amount of core polarization and the neutron eﬀective charge is found to been = 0.15e, much smaller than usual in the shell-model
calculations in the region (en = 0.5). This small value
obtained for the eﬀective charge in 16 C can be considered as an indication of the decoupling of the valence
neutrons from the 14 C core.
References
1) Y. Kanada-En’yo et al.: Phys. Rev. C 55, 2860 (1997).
2) J. Raynal: Phys. Rev. C 23, 2571 (1981).
3) J. Barrette et al.: Phys. Rev. C 62, 0340306 (2000).
4) A. M. Bernstein et al.: Phys. Rev. Lett. 42, 425 (1979).
5) N. Imai et al.: Phys. Rev. Lett. 92, 2501 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Density distribution of 17 B studied via its reaction
cross section measurement†
Y. Yamaguchi,∗1 C. Wu,∗2 A. Ozawa,∗3 T. Suzuki,∗4 D. Q. Fang,∗5 M. Fukuda,∗6 N. Iwasa,∗7 T. Izumikawa,∗8
R. Kanungo, R. Koyama,∗8 T. Ohnishi, T. Ohtsubo,∗8 W. Shinozaki,∗8 T. Suda,
M. Takahashi,∗8 and I. Tanihata∗9
NUCLEAR STRUCTURE, 17 B, density distribution, halo structure
The reaction cross section (σR ) for the neutron-richnucleus 17 B on a carbon target has been measured at
an energy of 77A MeV by the transmission method.
An enhancement of σR at intermediate energy compared with that at high energy was observed.1) Basedon the assumption of the core (15 B) plus valence twoneutron picture, the density distribution (ρ(r)) of 17 B
was deduced through the energy dependence of σR
using a ﬁnite-range Glauber-model calculation. The
ﬁnite-range Glauber-model calculation seems a useful
tool for determining the association of σR and ρ(r) in awide-energy region.2) We parameterized a ﬁnite-range
parameter by ﬁtting the energy dependence of σR forthe 12 C + 12 C system, including new data from Ref. 3.
We employed the ﬁnite-range Glauber-model calculation under the optical-limit (OL) approximation (1) as
well as the few-body (FB) approach (2).
(1) We assumed the ρ(r) of 17 B to be a HO-typefunction for the core (15 B) plus a square of Yukawa tailfunction for the valence two neutrons, and calculated
σR with a ﬁnite-range parameter. The width parameter of the HO-type function of the core, chosen to be
1.679 fm so as to reproduce σI of 15 B,4) is common toboth protons and neutrons. By ﬁtting the measured
σR with a free parameter, which is an asymptotic slopeof the square of Yukawa tail function, the best ﬁt was
obtained with χ2 = 8.03.
(2) Note that a few-body (FB) Glauber-model calculation may be more suitable for describing a weakly
bound system, like a halo nucleus.5,6) Thus, we applied the FB calculation to a three-body system (core+ neutron + neutron) of 17 B. The minimum χ2 was
2.53 with a free parameter, which is a fraction of the
wave function with the valence two-neutron conﬁguration of (2s1/2 )2J=0 or (1d5/2 )2J=0 .
We have applied the two methods mentioned above.
In the present analysis, the FB approach reproduces
the experimental data better than the OL approach
†
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8
∗9

Condensed from the article in Phys. Rev. C 70, 054320(2004)
Center for Nuclear Study, University of Tokyo
Peking University, China
University of Tsukuba
Saitama University
Chinese Academy of Sciences, China
Osaka University
Tohoku University
Niigata University
Argonne National Laboratory, USAfrom the point of the minimum χ2 value. However,many more assumptions are involved in the FB approach, in which the wave function is assumed to bea product of the halo neutron wave function and thecore wave function. Moreover, the slope of the tail is
ﬁxed by the weak binding energy of the valence twoneutron (S2n ).7) In contrast, an advantage of the OL
approach is the fact that the slope of the tail is independently determined from S2n . Thus, it is diﬃcult todecide which method is better for 17 B density distribution. Therefore, we include, as the ﬁnal ρ(r) of 17 B,
all the distributions obtained from these two methods,
shown in Fig. 1. It is clearly demonstrated that a longneutron tail with a signiﬁcant amplitude exists in thedensity distribution of 17 B. It was proved that theneutron tail in the density distribution is essential for17
B to reproduce the measured reaction cross sections.

Fig. 1. Final density distribution of 17 B with significant
amplitude of long neutron tail.

References
1) Y. Yamaguchi et al.: RIKEN Accel. Prog. Rep. 37, 52(2004).
2) T. Zheng et al.: Nucl. Phys. A 709, 103 (2002).
3) M. Fukuda: private communication.
4) A. Ozawa et al.: Nucl. Phys. A 608, 63 (1996).
5) J. S. Al-Khalili et al.: Phys. Rev. C 54, 1843 (1996).
6) Y. Ogawa et al.: Prog. Theor. Phys. Suppl. No. 142,
157 (2001).
7) G. Audi et al.: Nucl. Phys. A 624, 1 (1997).

47

RIKEN Accel. Prog. Rep. 38 (2005)

Isoscalar electric multipole strength in 14 O
H. Baba,∗1 S. Shimoura,∗1 T. Minemura, Y. U. Matsuyama,∗2 A. Saito,∗1 H. Akiyoshi, N. Aoi, T. Gomi,
Y. Higurashi, K. Ieki,∗2 N. Imai, N. Iwasa,∗3 H. Iwasaki,∗1 S. Kanno,∗2 S. Kubono,∗1 M. Kunibu,∗2
S. Michimasa, T. Motobayashi, T. Nakamura,∗4 H. Sakurai,∗5 M. Serata,∗2 E. Takeshita,∗2 S. Takeuchi,
T. Teranishi,∗6 K. Ue,∗5 K. Yamada, and Y. Yanagisawa

NUCLEAR REACTIONS: 14 O(α,α’), 60 A MeV; Inelastic α Scattering
Intermediate energy RI beams enable us to investigate excited unstable nuclei using inverse kinematics
and measuring decaying particles and γ rays. We performed the measurement of inelastic α scattering on
the light unstable nuclei 14 O. For light stable nuclei,
isoscalar electric multipole strength has been systematically studied1,2) using an inelastic scattering of 60
A MeV α and the isoscalar monopole (E0) and dipole(E1) resonance have been discussed, which are relevantto the incompressibility of nuclear matter.
In the present experiment, we aimed at measuring
the excitation energy spectrum and the isoscalar multipole strength in a wide energy range by the invariantmass method for various particle decay channels andthe multipole decomposition (MD) analysis.3)
The experiment was performed at the RIKEN
projectile fragment separator (RIPS). A beam of
60 A MeV 14 O was produced by the fragmentation reaction and bombarded on a 120-mg/cm2 thick liquidhelium secondary target. Outgoing particles were measured using a ∆E-E1-E2 plastic hodoscope located 4 m
downstream of the target. To obtain de-excitation γrays from the outgoing particles, an array of sixty-eight
NaI(Tl) scintillators were set around the secondary target. The excitation energy was constructed from themomentum vectors of decay products by the invariantmass method. We measured the decay channels of
14 ∗O → 13 N + p, 12 C + p + p, 10 C + α, 12 C∗1 +p + p, and 10 C∗1 + α.
In order to obtain the multipole strength distributions, the MD analysis with the distorted wave Born
approximation (DWBA) method has been extensively
used. In this analysis, the DWBA calculations forinelastic α scattering were performed using the computer code ECIS974) with external optical and transition potentials. We employed a single-folding modelwith a density-dependent nucleon-α interaction5) andisoscalar transition densities6,7) to obtain optical andtransition potentials.
Figure 1 shows the decomposed multipole strength
distributions of L = 0–3, and L ≥ 4 obtained from the
∗1
∗2
∗3
∗4
∗5
∗6

48

Center for Nuclear Study, University of Tokyo
Department of Physics, Rikkyo University
Department of Physics, Tohoku University
Department of Applied Physics, Tokyo Institute of Technology
Department of Physics, University of Tokyo
Department of Physics, Kyushu University

Fig. 1. Decomposed strength distributions of 14 O obtainedby sum of measured decay channels.

MD analysis. The integrated strengths up to 25.0 MeV
were identiﬁed corresponding to 37.7 ± 8.4, 72.4 ± 8.3,
15.9 ± 3.8, and 9.6 ± 3.7% of the isoscalar E0, E1,
E2, and E3 EWSR, respectively. In addition to thefragmented strength distributions as seen in light stable nuclei,1,2) substantial continuum strengths below
10 MeV for the isoscalar E0 and E1 response were
newly observed which may be due to the low thresholdof the proton in 14 O.
References
1) B. John et al.: Phys. Rev. C 68, 014305 (2003).
2) Y.-W. Lui et al.: Phys. Rev. C 64, 064308 (2001).
3) M. Itoh et al.: Phys. Lett. B 549, 58 (2002).
4) J. Raynal: ECIS97, unpublished.
5) A. Kolomiets et al.: Phys. Rev. C 61, 34312 (2000).
6) G. R. Satchler: Nucl. Phys. A 472, 215 (1987).
7) M. N. Harakeh and A. E. L. Dieperink: Phys. Rev. C
23, 2329 (1981).

RIKEN Accel. Prog. Rep. 38 (2005)

E1 strength of the subthreshold 3/2+ state in 15 O studied by
Coulomb excitation†
K. Yamada, T. Motobayashi, H. Akiyoshi, N. Aoi, Zs. Fülöp,∗1 T. Gomi, Y. Higurashi, N. Imai,∗2 N. Iwasa,∗3
H. Iwasaki,∗4 Y. Iwata,∗5 H. Kobayashi,∗6 M. Kurokawa, Z. Liu,∗7 T. Minemura,∗2 S. Ozawa,∗8 H. Sakurai,∗4
M. Serata,∗6 S. Shimoura,∗9 S. Takeuchi, T. Teranishi,∗10 Y. Yanagisawa, K. Yoshida, and M. Ishihara[Nuclear astrophysics, CNO cycle, Coulomb excitation]
The 14 N(p,γ)15 O reaction at low energies is particularly essential in the hydrogen-burning stage of a
massive main-sequence star as this reaction, being theslowest in the main CNO cycle under stellar conditions, dominates the rate of energy generation throughthe entire cycle. The behavior of the low-energy (p,γ)
capture yield is inﬂuenced by the tails of a few discretelevels. The s-wave resonance located 504 keV below
the p + 14 N threshold, which corresponds to the 3/2+
state at 6.793 MeV excitation energy in 15 O, has attracted much attention. Schröder et al. extracted theradiative width of the 3/2+ state to be Γγ = 6.3 eV.1)
A recent R-matrix analysis yielded the width Γγ =1.75 ± 0.60 eV,2) based on the same data as those used
in Ref. 1. A recent lifetime measurement showed the+3)mean life of 1.60+0.75−0.72 fs for the 3/2 state, which cor+0.34
responds to a width Γγ = 0.41−0.13 eV. The widths of
1.75 eV and 0.41 eV lead to negligible contribution of
the 3/2+ state to the 14 N(p,γ)15 O reaction rate, while
the width of 6.3 eV increases the astrophysical S-factor
at zero energy by approximately 50% compared withthat estimated without any resonance eﬀect. In thisarticle we report on a measurement of the radiative
width for the 3/2+ state in 15 O by intermediate-energy
Coulomb excitation. Because this method is independent of those employed in the earlier experiments, thisstudy is expected to provide complementary information and help resolve the conﬂicting situation mentioned above.
An 15 O beam was produced by the projectile fragmentation of an 16 O beam, and was isotopically separated by RIPS. The beam was focused onto a leadtarget of 1480 mg/cm2 thickness. The average energy
in the middle of the target was about 85 A MeV. The
typical 15 O intensity was about 4 × 105 counts per second. 15 O was identiﬁed by measuring the time-of-ﬂight(TOF) using a plastic scintillator and cyclotron RF†

Condensed from the article in Phys. Lett. B 579, 265 (2004)
ATOMKI, Hungary∗2 High Energy Accelerator Research Organization (KEK)∗3 Department of Physics, Tohoku University∗4 Department of Physics, University of Tokyo∗5 National Institute of Radiological Sciences∗6 Department of Physics, Rikkyo University∗7 Institute of Modern Physics, China∗8 Japan Atomic Energy Research Institute∗9 Center for Nuclear Study, University of Tokyo∗10 Department of Physics, Kyushu University∗1

signals. Reaction particles were identiﬁed by measuring the energies deposited in the ∆E and E plasticscintillator hodoscope placed 5.0 m downstream fromthe target, and the TOF between the plastic scintillator and the hodoscope. An array of 64 NaI(Tl) scintillators was placed around the lead target and wasused to detect de-excitation γ-rays. The Doppler shift
was corrected event by event using the γ-ray emission
angle.
The γ-ray spectrum obtained by the 63-degree detectors was analyzed with the following six components: four line shapes from the transitions in 15 O−→
(5.241 MeV (5/2+ → 1/2−
g.s. ), 6.176 MeV (3/2−+−
1/2g.s. ), 6.793 MeV (3/2 → 1/2g.s. ), and 7.276 MeV(7/2+ → 1/2−
g.s. )) obtained by the Monte-Carlo calculation; a target excitation component, and a continuous background component. The target excitation
component was determined from the energy spectrum
obtained by the backward-angle array detectors at 127
degrees. From the ﬁt, the resulting cross section was
found to be 0.55 ± 0.35 mb for the 6.8 MeV component. The radiative width for the 3/2+ state, Γγ =0.95 ± 0.60 eV, was derived from the cross section forthe 6.8 MeV component with the help of a distortedwave calculation assuming pure E1 Coulomb excitation. However, contributions from other γ-transitions
feeding the 6.8 MeV state could cause reduction ofthe Γγ value. Considering that the amount of thiseﬀect cannot be derived experimentally, it is appropriate to provide an experimental radiative width of
0.95+0.60−0.95 eV.
The present result provides an independent support
to the recent studies that yielded small Γγ values,3)
and 1.75 ± 0.60 eV.2) However, the pre0.41+0.34−0.13 eV,diction of 6.3 eV by Schröder et al.1) is not compatible
with the present Coulomb excitation result. This suggests that the role of the 3/2+ subthreshold state isconsiderably small and negligible for the low-energy
14N(p,γ)15 O cross section. Thus, a possible increasein the S-factor toward zero energy is not favorable incontrast to the prediction in Ref. 1.
References
1) U. Schröder et al.: Nucl. Phys. A 467, 240 (1987).
2) C. Angulo and P. Descouvemont: Nucl. Phys. A 690,
755 (2001).
3) P. F. Bertone et al.: Phys. Rev. Lett. 87, 152501 (2001).

49

RIKEN Accel. Prog. Rep. 38 (2005)

Study of 22 O(d,p)23 O reaction in inverse kinematics
Z. Elekes,∗1 Zs. Dombrádi,∗1 S. Bishop, Zs. Fülöp,∗1 J. Gibelin,∗2 T. Gomi, Y. Hashimoto,∗3 N. Imai,
N. Iwasa,∗4 H. Iwasaki,∗5 G. Kalinka,∗1 Y. Kondo,∗3 K. Kurita,∗6 M. Kurokawa, N. Matsui,∗3 T. Motobayashi,
T. Nakamura,∗3 T. Nakao,∗5 T. Ohnishi, T. Okumura,∗3 S. Ota,∗7 A. Perera, A. Saito,∗5 H. Sakurai,∗5
Y. Satou,∗3 D. Sohler,∗1 T. Sumikama, D. Suzuki,∗6 M. Suzuki,∗6 H. Takeda,∗5 S. Takeuchi, Y. Togano,∗6
and Y. Yanagisawa[NUCLEAR STRUCTURE, Unstable nuclei, transfer reaction, single-particle energies]
The structure of atomic nuclei is known to be largely
dominated by single-particle shell eﬀects. For instance,
basic nuclear properties such as binding energies andshapes depend strongly on the underlying shell structure. The study of nuclei beyond the valley of stability
is motivated by the understanding of the way singleparticle energies evolves when we owe move away fromstable nuclei to neutron and proton drip lines. This
would make more precise predictions of the limit of theexistence of nuclear species. In the case of light nuclei,
the rapid change in the location of the neutron drip
line between O and F species is still not understood.
The neutron drip line seems to be reached at N = 16
in O isotopes whereas in the neighboring F isotopes, it
has been found to extend up to N = 22.1) Obviously,
the understanding of how the shell structure evolves
from O to F nuclei should shed light on how nuclear
force could accommodate the binding of up to 6 neutrons in 31 F by the addition of a single proton. The
situation can be partly understood by assuming a sufﬁciently large N = 16 shell gap between the s1/2 andd3/2 neutron orbits, making the d3/2 orbit unboundin oxygen, but bound in F nuclei. To understand the
problems related to the N = 16 subshell closure at theneutron drip line, measurement of the energy of thesingle-particle states in 23 O is required. Since the ﬁrst
excited state in 23 O is expected to be unbound, theonly way to measure its energy is to search for a resonance in the cross section of a well-chosen reaction.
For this purpose, we studied the 2 H(22 O,23 O)1 H reaction in which a neutron and an 22 O nucleus is emitted
after the 23 O excited state was formed.
In the experiment, a 94 A· MeV energy primarybeam of 40 Ar with 60 pnA intensity hit a 9 Be production target of 0.5 cm thickness. The reaction products
were momentum- and mass-analyzed by the RIPS2)
fragment separator. The secondary beam mainly included neutron-rich 25 Ne and 22 O nuclei. The RIPS
was operated at 6% momentum acceptance. The total intensity was approximately 1500 cps having an av∗1
∗2
∗3
∗4
∗5
∗6
∗7

50

Institute of Nuclear Research, ATOMKI, Hungary
Institut de Physique Nucléaire, FranceTokyo Institute of Technology
Tohoku University
University of Tokyo
Rikkyo University
Kyoto University

erage 22 O intensity of 600 cps. The identiﬁcation ofincident beam species was performed by energy loss
and time-of-ﬂight.1) The secondary beam was transmitted to a CD2 target of 30 mg/cm2 at the ﬁnal focus of RIPS. The reaction occurred at an energy of
34 A· MeV. The position of the incident particles wasdetermined by two PPACs placed at F3 upstream of
the target. The scattered particles were detected andidentiﬁed by a 2 × 2 matrix silicon telescope placed
96 cm downstream of the target. The telescope consisted of three layers with thicknesses of 0.5, 0.5, 2
and 2 mm. The ﬁrst two layers were made of stripped
detectors measuring the x and y positions of the fragments. On the basis of ∆E-E information, isotope
separation was carried out among the diﬀerent oxygen isotopes. The protons emitted backward during
the reaction were detected by 156 CsI(Tl) scintillator
crystals read out by photodiodes. 80 NaI(Tl) scintillator detectors also surrounded the target to detect deexciting γ rays emitted by the inelastically scatterednuclei. The neutrons coming from the breakup of theexcited 23 O nuclei were detected by a neutron wall consisting of four layers placed 2.5 m downstream of thetarget. The schematic view of the experimental setup
is shown in Fig. 1. The analysis of the data is now inprogress.

Fig. 1. Schematic view of experimental setup.

References
1) H. Sakurai et al.: Phys. Lett. B 448, 180 (1999).
2) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).

RIKEN Accel. Prog. Rep. 38 (2005)

Proton single particle states in 23 F
S. Michimasa, S. Shimoura,∗1 H. Iwasaki,∗2 M. Tamaki,∗1 S. Ota,∗3 N. Aoi, H. Baba,∗1 N. Iwasa,∗4 S. Kanno,∗5
S. Kubono,∗1 K. Kurita,∗5 M. Kurokawa, T. Minemura, T. Motobayashi, M. Notani,∗6 H. J. Ong,∗2 A. Saito,∗1
H. Sakurai,∗2 S. Takeuchi, E. Takeshita,∗5 Y. Yanagisawa, and A. Yoshida
NUCLEAR REACTIONS: 4 He(22 O,23 F∗ ), 4 He(23 F,23 F∗ ), 4 He(24 F,23 F∗ ), Single-particle
state, In-beam γ-ray spectroscopy
We have measured de-excited γ rays from 23 F produced by the proton transfer reaction 4 He(22 O,23 F∗ ),the inelastic scattering 4 He(23 F,23 F∗ ) and the neutron
knockout reaction 4 He(24 F,23 F∗ ). The 23 F isotope locates in the vicinity of the exotic magic number of
N = 16.1) In the region, numerous experimental works
were performed to investigate neutron contributions to
the exotic phenomenon. Here, we considered the proton shell structure in the neutron-rich nucleus 23 F, andsearched proton single-particle states in 23 F on the basis of the diﬀerence in population strength among theabove-mentioned reactions.
The experiment was performed at the RIPS beamline in RIKEN. 40 Ar ions were accelerated up to
63 MeV/nucleon using the linear accelerator scheme of
RFQ-RILAC-CSM-RRC. The maximum intensity ofthe primary beam was achieved up to 800 pnA. The
primary target was 9 Be with a thickness of 1 mm. The
secondary beam was a cocktail of 22 O, 23 F and 24 F,
and produced by their projectile fragmentation reaction. The averaged beam energies of 22 O, 23 F and 24 F
were 35, 41.5 and 36 MeV/nucleon, and these intensities were 2 × 103 , 6 × 102 and 3 × 102 cps, respectively.
The secondary beam bombarded a liquid helium target2) of 100 mg/cm2 with havar foil windows. Reaction
products were identiﬁed using a telescope consisting of
9 SSDs and 36 NaI(Tl) scintillators.3) The scattering
angles of the reaction products were measured using
three PPACs. The resolution of the scattering angle
were estimated to be 0.25 degrees (σ) in laboratory
coordinates. Furthermore, de-excitation γ rays fromthe reaction products were detected using 150 NaI(Tl)scintillators4) surrounding the secondary target.
In the analysis, we examined coincidences of multiple γ rays in the above-mentioned reactions and preliminarily reconstructed the γ-decay scheme in 23 F as
shown in Fig. 1. Level energies with underlines show
newly observed excited states in the present experiment. The bar graphs on the right side of the excitation energies show the relative cross sections topopulate these excited states. In these relative crosssections, one can observe that the 4.06-MeV state is
∗1
∗2
∗3
∗4
∗5
∗6

Center for Nuclear Study, University of Tokyo
Department of Physics, University of Tokyo
Department of Physics, Kyoto University
Department of Physics, Tohoku University
Department of Physics, Rikkyo University
Argonne National Laboratory, USA

Fig. 1. Proposed level and γ-decay scheme in 23 F. Level
energies with underlines show newly observed excitedstates in the present experiment. The bars on the rightside of excitation energies show the relative cross sections to populate these states.

strongly populated by the proton transfer reaction, but
hardly populated by the other reactions. This strongly
suggests that the 4.06-MeV state has a single-particle
nature. The angular distribution of scattered 23 F ionsfor the 4.06-MeV state was compared with DWBA
calculations. The measured angular distribution was
found to agree with the  = 2 transition. Therefore,
the 4.061-MeV state was preliminarily assigned to haveJ π = 3/2+ or 5/2+ .
References
1) A. Ozawa et al.: Phys. Rev. Lett. 84, 5493 (2000).
2) H. Akiyoshi et al.: RIKEN Accel. Prog. Rep. 34, 193(2001).
3) M. Tamaki et al.: CNS-REP-59, 76 (2003).
4) S. Takeuchi et al.: RIKEN Accel. Prog. Rep. 36, 148(2003).

51

RIKEN Accel. Prog. Rep. 38 (2005)

Bound excited states in 27 F†
Z. Elekes,∗1 Zs. Dombrádi,∗1 A. Saito,∗2 N. Aoi, H. Baba,∗2 K. Demichi,∗2 Zs. Fülöp,∗1 J. Gibelin,∗3 T. Gomi,
H. Hasegawa,∗2 N. Imai,∗4 M. Ishihara, H. Iwasaki,∗4 S. Kanno,∗2 S. Kawai,∗2 T. Kishida, T. Kubo,
K. Kurita,∗2 Y. Matsuyama,∗2 S. Michimasa, T. Minemura, T. Motobayashi, M. Notani,∗4 T. Ohnishi,∗4
H.J. Ong,∗4 S. Ota,∗5 A. Ozawa,∗6 H. K. Sakai,∗2 H. Sakurai,∗4 S. Shimoura,∗4 E. Takeshita,∗2 S. Takeuchi,
M. Tamaki,∗4 Y. Togano,∗2 K. Yamada, Y. Yanagisawa, and K. Yoneda

NUCLEAR STRUCTURE, Unstable nuclei, 27 F bound excited states
It is known that the last bound oxygen neutron-richnucleus is 24 O, while when adding one more proton tothe oxygen isotopes even 31 F is bound.1) A straightforward way of understanding this phenomena is to
assume that the νd3/2 neutron orbit is unbound in oxygen isotopes, while the additional proton in the ﬂuors
can make this state bound. This assumption is sufﬁcient for explaining the existence of 27,29 F, but forunderstanding the bound nature of 31 F, additional assumptions are required. In terms of the shell model, asudden lowering of multiparticle multihole states may
be an explanation.2) If this is valid, the traces of thislowering must also be apparent in the lighter F isotopes. In 27 F, the ﬁrst excited state is expected to be
unbound in the usd3) approximation; while allowing
for particle-hole excitations to the f p shell, a bound excited state in 27 F is expected. To identify such states,
we studied the 27 F(p,p γ) reaction.
In the present experiment, a 94 A· MeV energy primary beam of 40 Ar with 60 pnA intensity hit a 181 Ta
production target of 0.5 cm thickness. The reaction
products were momentum- and mass-analyzed by using the RIPS4) fragment separator. The secondary
beam included neutron-rich 24 O, 25,26,27 F, 27,28,29,30 Ne
and 29,30,31,32 Na nuclei. The RIPS was operated at 6%
momentum acceptance. The total intensity was approximately 100 cps having an average 27 F intensity of
4 cps. The identiﬁcation of incident beam species was
performed by means of energy loss, time-of-ﬂight andmagnetic rigidity (Bρ) analyses.5) 27 F particles could
be fully separated from other nuclei. The secondary
beam was transmitted to a liquid hydrogen target6) at
the ﬁnal focus of RIPS. The average areal density of
the hydrogen was 210 mg/cm2 . The position of the incident particles was determined by two PPACs placed
at F3 upstream of the target. The scattered particles
were detected and identiﬁed by a PPAC and a silicon telescope, respectively. The telescope consisted ofthree layers with thicknesses of 0.5, 0.5 and 1 mm. The
Z identiﬁcation was performed by using of the TOF†
∗1
∗2
∗3
∗4
∗5
∗6

52

Condensed from the article in Phys. Lett. B 599, 17 (2004)
Insitute of Nuclear Research, ATOMKI, Hungary
Rikkyo University
Institut de Physique Nucléaire, France
University of Tokyo
Kyoto University
University of Tsukuba

energy-loss method. Based on ∆E-E information, isotope separation was carried out among the diﬀerent ﬂuorine isotopes. 27 F nuclei represented a distinct peak
and they were well separated from other products thatemerged due to neutron removal reactions in the liquidhydrogen target. The new DALI2 setup, including 146
NaI(Tl) scintillator detectors,7) surrounded the target
to detect the de-exciting γ rays emitted by the inelastically scattered nuclei. The 27 F spectrum showed two
peaks at 504(15) and 777(19) keV. The experimental
data can be compared with the predictions of the shellmodel calculations. According to the sd shell model,9)a 5/2+ ground state is expected with the 1/2+ state as
the ﬁrst excited state at 1997 keV, which means thatboth levels of 27 F appear at energies which are too low.
Extending the model space to the sdpf shells,8) a lowering to 1.1 MeV of the 1/2+ excited state is calculated
in 27 F. Although an excited state with a similar energy can be constructed by placing the two γ rays of27
F on top of each other, on the basis of the expecteddecay properties, a state directly feeding the groundstate is a more probable candidate for the spin 1/2
state. In spite of the ∼300 keV energy diﬀerence, the777 keV transition may be a reasonable candidate forthe decay of the 1/2+ state of the sdpf shell model prediction. The large energy deviation between at least
one of the predicted and observed excited states suggests that these states intrude from a conﬁguration
outside of the model space, or that the predicted energies strongly deviate from the observed ones due tosome additional correlations not included in the models.
References
1) H. Sakurai et al.: Phys. Lett. B 448, 1147 (1990).
2) Y. Utsuno et al.: Phys. Rev. C 64, 011301 (2001).
3) T. Otsuka et al.: Eur. Phys. J. A 15, 151 (2002).
4) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
5) H. Sakurai et al.: Phys. Lett. B 448, 180 (1999).
6) H. Akiyoshi et al.: RIKEN Accel. Prog. Rep. 32, 167(1999).
7) H. Hasegawa et al.: RIKEN Accel. Prog. Rep. 35, 169(2002).
8) Y. Utsuno, et al.: Phys. Rev. C 60, 054315 (1999).
9) B. A. Brown: http://www.nscl.msu.edu/ brown/
sde.htm

RIKEN Accel. Prog. Rep. 38 (2005)

In-beam gamma spectroscopy of 25 Ne via 26 Ne breakup
J. Gibelin,∗1,∗2 N. Aoi, H. Baba,∗2 D. Beaumel,∗1 Y. Blumenfeld,∗1 Z. Elekes, N. Fukuda, T. Gomi,
K. Ishikawa,∗3 Y. Kondo,∗3 T. Kubo, V. Lima,∗1 T. Motobayashi, T. Nakamura,∗3 A. Saito, Y. Satou,∗3
E. Takeshita,∗2 S. Takeuchi, T. Teranishi,∗4 Y. Togano,∗2 A. M. Vinodkumar∗3 , Y. Yanagisawa, and K. YoshidaGamma spectroscopy, 25 Ne
The Coulomb excitation of 26 Ne has been studied
in a recent experiment performed at RARF. We report here on the bound states of 25 Ne populated in
the breakup of 26 Ne.
A 26 Ne beam was produced by the RIKEN Projectile
fragment Separator (RIPS) after a 2-mm-thick Be production target was bombarded with a 95 A MeV 40 Ar
beam. We obtained a secondary 26 Ne beam with anenergy of 58 A MeV, an average rate of 10 kcps and apurity of 80%. The main contaminant was 29 Mg. The
beam impiged on a 230 mg/cm2 Pb target.
Particle identiﬁcation was performed using a wall ofsilicon detectors placed 1.2 m downstream of the target. It consisted of two layers of 8 silicon strip detectors(SSD) and a layer of 3-mm-thick Si(Li) (8 pieces) fromthe charged-particle detector MUST.1) Energy calibration was performed using a 25 Ne beam of 0.1% momentum resolution at three diﬀerent energies (50, 55 and
60 A MeV).
25
Ne nuclei were identiﬁed with the E-∆E correlation. ∆E is the sum of energy loss in SSD and E thesum of ∆E and the residual energy in Si(Li). After selecting Ne isotopes, we project this 2D histogram onto
a 1D histogram representing the mass number A of the2)
Ne isotopes.
the range formula, we wrote A as
 ζ+ηFrom∆E
ζ+η ∆E+κ. We adjusted− (E − ∆E)
A = λ. E
the four coeﬃcients λ, κ, ζ, η to obtain independence
from incident energy and a resolution of δA/A ≈ 10%,see result in Fig. 1.
In-beam gamma rays were detected using the 4πgamma-detector DALI2,3) which consists of 152 NaI
detectors, placed around the target. For 2 MeV γ-rays,

its eﬃciency is typically 10% with an energy resolution
of 7% (FWHM).
Finally, an hodoscope for neutron detection wasplaced 3.5 m downstream of the target. Its total intrinsic eﬃciency is ∼ 30% for neutrons at 50 A MeV.
The Doppler-corrected gamma distribution in coincidence with 25 Ne fragments detected by the siliconwall is plotted in Fig. 2 (left). The accuracy of thecalibration is tested by comparing the energies of theﬁrst 2+ state of: 26 Ne at 2018.2 ± .1 keV and 24 Ne
at 1981.6 ± .4 keV. We obtained 2010 ± 60 keV and1983 ± 75 keV, respectively.
The resolution of 125 keV (FWHM) is not suﬃcient to separate the states at 1613 and 1703 keV
in 25 Ne. However, we conﬁrm the state at 2050 ±80 keV initially measured at 2030 ± 50 keV in the26
Mg(7 Li,8 B)25 Ne transfer reaction4) but unseen in
the 26 Mg(13 C,14 O)25 Ne transfer reaction5) and β decay from 25 F.6)
No contribution of the 2188 keV γ-ray from the3891.2 keV state is observed.

Fig. 2. Left: Doppler-corrected gamma ray spectrum incoincidence with 25 Ne fragments after exponential background substraction. Superimposed histograms: resultsof simulations using GEANT 3. Right: Known levelsof 25 Ne.

References

Fig. 1. Projected E-∆E histogram onto A, neon isotope
mass number, in coincidence with neutron events inneutron detectors.
∗1
∗2
∗3
∗4

Institut de Physique Nucléaire, France
Department of Physics, Rikkyo University
Department of Physics, Tokyo Institute of Technology
Center for Nuclear Study, University of Tokyo

1) Y. Blumenfeld et al.: Nucl. Instrum Methods Phys. Res.
A 421, 471 (1999).
2) F. S. Goulding: Treatrise on Heavy-Ion Science, 7,(Plenum, New York, 1985), p.285.
3) S. Takeuchi et al.: RIKEN Accel. Prog. Rep. 36, 148(2003).
4) R. H. Wilcox et al.: Phys. Rev. Lett. 30, 866 (1973).
5) C. L. Woods et al. Nucl. Phys. A 437, 454 (1985).
6) A. T. Reed et al.: Phys. Rev. C 60, 024311 (1999).

53

RIKEN Accel. Prog. Rep. 38 (2005)

First excited state in 23 Al
with Coulomb dissociation method
T. Gomi, T. Motobayashi, Y. Ando,∗1 N. Aoi, H. Baba,∗2 K. Demichi,∗1 Z. Elekes,∗3 N. Fukuda,
Zs. Fülöp,∗3 U. Futakami,∗1 H. Hasegawa,∗1 Y. Higurashi, K. Ieki,∗1 N. Imai,∗4 M. Ishihara, K. Ishikawa,∗5
N. Iwasa,∗6 H. Iwasaki,∗7 S. Kanno,∗1 Y. Kondo,∗5 T. Kubo, S. Kubono,∗2 M. Kunibu,∗1 K. Kurita,∗1
Y. U. Matsuyama,∗1 S. Michimasa, T. Minemura, M. Miura,∗5 H. Murakami,∗1 T. Nakamura,∗5 M. Notani,∗8
S. Ota,∗9 A. Saito,∗2 H. Sakurai,∗7 M. Serata,∗1 S. Shimoura,∗2 T. Sugimoto,∗5 E. Takeshita,∗1 S. Takeuchi,
Y. Togano,∗1 K. Ue,∗7 K. Yamada, Y. Yanagisawa, K. Yoneda, and A. Yoshida
NUCLEAR REACTIONS, 208 Pb(23 Al,22 Mg p)208 Pb, Coulomb dissociation
The ﬁrst excited state in 23 Al is important as a resonant state in the stellar 22 Mg(p,γ)23 Al reaction. This
stellar reaction is relevant to nucleosynthesis in explosive hydrogen burning, which occurs in novae and Xray bursts. The energy of the ﬁrst excited state is
known to be 0.528 MeV;1) however, there is no experimental data for the radiative width that has a direct
eﬀect on the astrophysical reaction rate.
A Coulomb dissociation method for radioactive nuclei has an attractive feature, that is, a high experimental eﬃciency. Using this method, one can determine
the radiative width and extract the transition multipolarity from the distribution of the scattering angleof 23 Al.
The experiment was performed at the RIPS beamline. A secondary beam of 23 Al at 50 MeV/nucleon
bombarded an 88 mg/cm2 Pb target. The products ofthe breakup reaction, 22 Mg and a proton, were detected respectively using a silicon counter telescope
and a plastic scintillator hodoscope located 50 cm and
3 m downstream of the target. The silicon telescopeconsisted of four layers of detectors of 0.5 mm thickness. Each layer consisted of eight detectors with aneﬀective area of 50 × 50 cm2 . These eight detectors
formed a 3 × 3 matrix with a hole in the center. The
detectors in the ﬁrst and second layers consisted of 5mm-wide strip electrodes, which enabled position measurement in the horizontal and vertical directions. A
stack of sixty-eight NaI(Tl) scintillators (DALI) was
placed around the target to measure de-excitation γrays from 22 Mg in the excited state, the contributionof which should be subtracted to extract the Coulomb
dissociation cross section of interest. The details of theexperimental setup can be found in Ref. 2.
The relative energies of 22 Mg and the proton were
determined from the invariant mass, which was ex∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8
∗9

54

Rikkyo University
Center for Nuclear Study, University of TokyoATOMKI, Hungary
High Energy Accelerator Research Organization (KEK)Tokyo Institute of Technology
Tohoku University
University of Tokyo
Argonne National Laboratory, USA
Kyoto University

tracted from the momenta of particles. We identiﬁed
the breakup reaction through the ﬁrst excited statein 23 Al, and extracted the angular distribution of thescattered 23 Al as shown in Fig. 1. The scattering angle was deﬁned as the angle of the p-22 Mg center ofmass with respect to the beam direction in the laboratory coordinates. For comparison, the theoreticalangular distribution obtained by distorted-wave calculation when we assumed an E2 transition is shown. In
this calculation, we used the optical potential parameters determined for the 17 O + 208 Pb reaction.3) The
calculated distribution matches well with the experimental data. This is consistent with the theoreticalprediction that the spin and parity of 23 Al are 5/2+ forthe ground state and 1/2+ for the ﬁrst excited state.
Further analysis is now in progress.

Fig. 1. Angular distribution of the scattered 23 Al. The
filled circles show the experimental data. The solid
curve represents the result of a distorted-wave calculation with the angular-momentum transfer l = 2.

References
1) J. A. Caggiano et al.: Phys. Rev. C 64, 025802 (2001).
2) T. Gomi et al.: RIKEN Accel. Prog. Rep. 36, 82 (2003).
3) J. Barrette et al.: Phys. Lett. B 209, 182 (1988).

RIKEN Accel. Prog. Rep. 38 (2005)

Measurement of momentum distribution and reaction cross section
for proton-rich nucleus 23 Al
Y. G. Ma,∗1 D. Q. Fang,∗1 X. Z. Cai,∗1 W. Q. Shen,∗1 Z. Y. Sun,∗2 Z. Z. Ren,∗3 W. Guo,∗1 Y. B. Wei,∗1
K. Wang,∗1 T. Z. Yan,∗1 C. W. Ma,∗1 J. G. Chen,∗1 J. H. Chen,∗1 G. L. Ma,∗1 Q. M. Su,∗1 W. D. Tian,∗1
C. Zhong,∗1 J. X. Zuo,∗1 M. Hosoi,∗4 T. Izumikawa,∗5 R. Kanungo, S. Nakajima,∗4 T. Ohnishi, T. Ohtsubo,∗5
A. Ozawa,∗6 T. Suda, K. Sugawara,∗4 T. Suzuki,∗4 A. Takisawa,∗5 K. Tanaka, T. Yamaguchi,∗4
and I. Tanihata∗7
Measured fragment momentum distribution, measured reaction cross section, proton halo
structure
Recently, the measurement of the momentum distribution has conﬁrmed the existence of a proton halo in
26,27,28 1)
P. Reaction cross sections (σR ) of N = 10 ∼15 isotones were measured in Lanzhou on the HIRFLRIBLL.2) A remarkable enhancement of σR for 27 P
and 23 Al is observed as compared with their neighboring nuclei. This result, together with the small proton
separation energy, strongly suggests the existence ofa proton halo in 27 P and 23 Al.2,3) For 23 Al, it is interesting to investigate the possible cause for the appearance of the proton halo. In the ground state of23
Al, the last proton may occupy the level 1d5/2 or
2s1/2 in the spherical shell model. When the last proton occupies 1d5/2 , a large centrifugal barrier tends tosuppress the formation of a halo. If there exist deformations in the nuclei, the situation may become more
complex because both prolate and oblate deformations
can appear. Here it is unclear which case the nucleus
23
Al will belong to. The experimental ground statespin and parity of this nucleus is not yet available.
Thus a correct description of the proton halo in 23 Al
may present a new challenge to the existing theoretical models. 23 Al is between the halo nuclei 17 Ne and26,27
P. It may play an important role for the study of
proton halos in 2s-1d shell nuclei. It bridges the gap
between 17 Ne and 26,27 P. Since the momentum distribution and σR measurement are very useful methods
for halo structure investigation, we have performed thisexperiment for further clariﬁcation of the halo structure in 23 Al.
The experiment was performed at the Riken Projectile Fragment Separator (RIPS). The primary beam of
135 A MeV 28 Si was used to produce the secondary
beam of 23 Al. Before the carbon target (377 mg/cm2 )installed at F2, particle identiﬁcation was carried out
by using the Bρ-∆E-TOF method. The TOF wasdetermined from a delay-line PPAC at F1 and aplastic scintillator (0.5 mm thick) at F2. ∆E was
∗1
∗2
∗3
∗4
∗5
∗6
∗7

Shanghai Institute of Applied Physics, China
Institute of Modern Physics, China
Department of Physics, Nanjing University, China
Department of Physics, Saitama University
Department of Physics, Niigata University
Department of Physics, University of Tsukuba
Argonne National Laboratory, USA

measured using the newly constructed Ion Chamber(200φ × 780 mm). After the carbon target, the TOF∆E-E method was used for particle identiﬁcation. Another plastic scintillator (1.5 mm thick) at F3 gave thestop signal of the TOF from F2 to F3. The Ion Chamber (90φ × 650 mm) was used to measure ∆E. E wasmeasured by the 3 φ×6 cm NaI(Tl) detector with vetocounters.4)
The measurement of σR was carried out by using
a transmission-type method. σR was determined by
the ratios between the incident and outgoing particles
without reaction from both target-in and target-out
measurements. The longitudinal momentum distributions of fragments from the breakup reactions were determined from the TOF between the two plastic scintillators installed at F2 and F3. The position informationfrom F1-PPAC was used to derive the incident momentum.5) The particle identiﬁcation for fragments 22 Mg
at F3 is shown in Fig. 1. This spectrum was obtained
after substructing fragments with diﬀerent charges by
the TOF and ∆E methods. The detailed analysis of
momentum distribution and σR data are in progress.

Fig. 1. Particle identification plot for fragments 22 Mg at F3
by using TOF from F2 to F3 and energy informationfrom NaI(Tl).

References
1) A. Navin et al.: Phys. Rev. Lett. 81, 5089 (1998).
2) D. Q. Fang et al.: Eur. Phys. J. A 12, 335 (2001).
3) X. Z. Cai et al.: Phys. Rev. C 65, 024610 (2002).
4) T. Suda et al.: RIKEN Accel. Prog. Rep. 35, 171 (2002).
5) R. Kanungo et al.: Phys. Rev. Lett. 88, 142502 (2002).

55

RIKEN Accel. Prog. Rep. 38 (2005)

Proton resonant states in 23 Al using a radioactive beam of 22 Mg
J. J. He,∗1 S. Kubono,∗1 T. Teranishi,∗1,∗2 M. Notani,∗1,∗3 H. Baba,∗1 S. Nishimura, J. Y. Moon,∗4
M. Kurata-Nishimura, S. Michimasa,∗1 H. Iwasaki,∗5 Y. Yanagisawa, N. Hokoiwa,∗2 M. Kibe,∗2 J. H. Lee,∗4
S. Kato,∗6 Y. Gono,∗2 and C. S. Lee∗4[Proton Resonant State, Nuclear Astrophysics]
The stellar 22 Mg(p, γ)23 Al reaction is an important
reaction in the Hot NeNa-cycle, because it inﬂuences
the production of 22 Na in nova ejecta.1–3) The higher
energy proton resonant states (E x ≥1.77 MeV) also
contribute to the X-ray burst and supernova events.
In addition, the proton resonance information in 23 Al
is very important from the nuclear-structure point ofview. In the present study, we directly investigatedproton resonant states in 23 Al by resonant elastic scattering of an 22 Mg RI beam on a thick hydrogen target.
The experiment was performed in the CNS radioactive ion beam separator (CRIB).4,5) The experimental
procedure and setup were described previously6) in detail. This report will only show the recent results.
Figure 1 shows the experimental proton spectrum for22
Mg+ p scattering at θcm = 180◦ . The proton threshold in 23 Al is known to be 0.123 MeV.2) Therefore, theexcitation energy in 23 Al is calculated by E x = E cm +0.123 MeV. It should be pointed out that the spectrum
was obtained by assuming elastic scattering of 22 Mg+
p. Therefore, in a case of inelastic scattering, the E cm
energy in the ﬁgure must be corrected. The inelastic
scattering contributions were evaluated by comparing
the experimental scattering data at three diﬀerent angles. From a detailed analysis of kinematics, it has
been concluded that via proton emission, the excitedstate at 3.00 MeV decays to the ground state in 22 Mg,
while the excited states at 3.14, 3.24 and 3.93 MeV decay to the ﬁrst excited state in 22 Mg. A new level
scheme of 23 Al is proposed in Fig. 2.
The experimental results were analyzed using the Rmatrix code SAMMY-M6-BETA,7) which enables multilevel R-matrix ﬁts to neutron and charged-particle
cross-section data using Bayes’ equations. A preliminary R-matrix ﬁt was performed for the resonant stateat E x = 3.00 MeV, and a d -wave ﬁt reproduces theexperimental data very well. Therefore, we assign thisstate with the spin-parity of (3/2+ , 5/2+ ). Three otherexcited states (at 3.14, 3.24 and 3.93 MeV) in the 23 Al
nucleus decay to the ﬁrst excited state in 22 Mg probably via d -wave proton emissions. The spin-parity ofthese three excited states is tentatively assigned as
J π = (7/2+ ). It is concluded that the excited states
at 3.00 and 3.93 MeV are the newly observed excitedstates in 23 Al, and one of the excited states at 3.14 and3.24 MeV could correspond to the previously observed
state at 3.204 MeV.2) Further analysis of the resonant
properties of these states is in progress.

Fig. 2. Level scheme in 23 Al proposed by the present experiment.

References
Fig. 1. Experimental proton spectrum for 22 Mg+p scattering (elastic and inelastic) at θcm = 180◦ .
∗1
∗2
∗3
∗4
∗5
∗6

56

Center of Nuclear Study, University of Tokyo
Department of Physics, Kyushu University
Argonne National Laboratory, USA
Department of Physics, Chung-Ang University, Korea
Department of Physics, University of Tokyo
Department of Physics, Yamagata University

1) I. Iyudin et al.: Astron. Astrophys. 300, 422 (1995).
2) J. A. Caggiano et al.: Phys. Rev. C 64, 025802 (2001).
3) M. Wiescher et al.: Astron. Astrophys. 160, 56 (1986).
4) S. Kubono et al.: Eur. Phys. J. A 13, 217 (2002).
5) T. Teranishi et al.: Phys. Lett. B 556, 27 (2003).
6) J. J. He et al.: CNS Annu. Rep. 2003, 34 (2004).
7) N. M. Larson: ORNL/TM-9179/R5, Oak Ridge National Laboratory (2000).

RIKEN Accel. Prog. Rep. 38 (2005)

Study of proton resonant states in 22 Mg
using radioactive beam of 21 Na
J. J. He,∗1 S. Kubono,∗1 T. Teranishi,∗1,∗2 M. Notani,∗1,∗3 H. Baba,∗1 S. Nishimura, J. Y. Moon,∗4
M. Nishimura, S. Michimasa,∗1 H. Iwasaki,∗5 Y. Yanagisawa, N. Hokoiwa,∗2 M. Kibe,∗2 J. H. Lee,∗4 S. Kato,∗6
Y. Gono, and C. S. Lee∗4[Proton Resonant State, Nuclear Astrophysics]
Observation of the characteristic 22 Na (E γ =1.275 MeV) activity with satellite γ telescopes suchas COMPTEL only yielded the upper limit, which issubstantially below the predicted abundances.1–3) This
discrepancy may be explained by the insuﬃciency of
the theoretical models, but there are still considerable
uncertainties with respect to the nuclear physics aspects. A better understanding of this issue requires accurate experimental data on the proton resonant statesin 22 Mg. We have investigated the proton resonant
states in 22 Mg using the resonant elastic scattering ofa 21 Na RI beam on a thick hydrogen target.
The experiment was performed using the CNS
radioactive-ion-beam separator (CRIB).5,6) An
8.11 A MeV primary beam of 20 Ne8+ bombarded awater-cooled 3 He gas target (0.36 mg/cm2 ), and a 21 Na
beam was produced by the 3 He(20 Ne, 21 Na)X reaction.
The secondary 21 Na beam was separated in CRIB and
used in the experiment as described elsewhere4) in detail.
A thick (CH2 )n foil (7.9 mg/cm2 ) was used in the experiment. A carbon target (9.3 mg/cm2 ) was also used
in a separate run for evaluating the background contribution. At the secondary target position, the averageintensity of 21 Na was 1.5×104 particles/s with a purityof 8.3%, and the mean energy was 4.00 MeV/nucleon
with a width (FWHM) of 0.16 MeV/nucleon. The 21 Na
particles were stopped in the target, and only the recoiled products were measured using the ∆E-E Si telescopes. The identiﬁcation of beam particles and recoiled protons is also described in Ref. 4.
The center-of-mass energies (E cm ) were deduced using the elastic scattering kinematics of 21 Na + p andconsidering the energy loss of particles in the target. Contribution from the inelastic scattering 21 Na(p,p’γ(0.33))21 Na is not considered in the present report. At θcm = 180◦ , the typical energy resolutions (FWHM) in E cm are approximately 20 keV at
E cm = 0.5 MeV and 45 keV at E cm = 3.5 MeV. The
systematic uncertainties in E cm are approximately±12 keV at 1.0 MeV and ±20 keV at 3.5 MeV.
Figure 1 shows the experimental center-of-mass en∗1
∗2
∗3
∗4
∗5
∗6

Center for Nuclear Study, University of Tokyo
Department of Physics, Kyushu University
Argonne National Laboratory, USA
Department of Physics, Chung-Ang University, Korea
Department of Physics, University of Tokyo
Department of Physics, Yamagata University

Fig. 1. Experimental center-of-mass energy spectrum for21
Na+p elastic scattering at θcm = 180◦ (without deadlayer region).

ergy spectrum for the 21 Na + p scattering at θcm =170◦ ∼ 180◦ . After correction for the number of 21 Na
beam particles and the stopping cross sections (dE/dx)
of the beam particles in the target material, the diﬀerential cross sections (dσ/dΩ) of 21 Na+p elastic scattering can be deduced.7) The proton threshold in 22 Mg isknown to be 5.50 MeV.8) Therefore, the excitation energy in 22 Mg can be calculated by E x= Ecm+5.50 MeV.
Some excitation energies are indicated on the ﬁgure.
The arrows indicate possible excited states in 22 Mg
which were observed previously.8)
The experimental results are being analyzed by the
R-matrix code SAMMY-M6-BETA,9) which enables
multilevel R-matrix ﬁts to neutron and chargedparticle cross-sectional data using Bayes’ equations.
The resonance properties such as E r , Γp and J π canbe deduced from the analysis.
References
1) I. Iyudin et al.: Astron. Astrophys. 300, 422 (1995).
2) M. Wiescher and K. Langanke: Z. Phys. A 325, 309(2002).
3) C. Ruiz et al.: Phys. Rev. C 65, 042801 (2002).
4) J. J. He et al.: CNS Annu. Rep. 2003, 34 (2004).
5) S. Kubono et al.: Eur. Phys. J. A 13, 217 (2002).
6) T. Teranishi et al.: Phys. Lett. B 556, 27 (2003).
7) S. Kubono: Nucl. Phys. A 693, 221 (2001).
8) A. A. Chen et al.: Phys. Rev. C 63, 065807 (2002).
9) N. M. Larson: ORNL/TM-9179/R5, Oak Ridge National Laboratory, (2000).

57

RIKEN Accel. Prog. Rep. 38 (2005)

Coulomb excitation of 20 Mg
N. Iwasa,∗1 S. Bishop, Z. Elekes,∗2 J. Gibelin,∗3,∗4 M. Hosoi,∗5 K. Ieki,∗3 K. Ishikawa,∗6 H. Iwasaki,∗7
S. Kawai,∗3 S. Kubono,∗8 K. Kurita,∗3 M. Kurokawa, N. Matsui,∗6 T. Minemura,∗9 H. Morikawa,∗3
T. Nakamura,∗6 M. Niikura,∗8 M. Notani,∗8 S. Ota,∗8,∗10 A. Saito,∗8 H. Sakurai,∗7 S. Shimoura,∗8
K. Sugawara,∗5 T. Sugimoto,∗6 H. Suzuki,∗7 T. Suzuki,∗5 E. Takeshita, S. Takeuchi, I. Tanihata∗11 ,T. Teranishi,∗12 Y. Togano,∗3 K. Yamada,∗3 K. Yamaguchi,∗3 Y. Yanagisawa, and T. Motobayashi

NUCLEAR REACTIONS: 20 Mg+Pb, Coulomb excitation
The Coulomb excitation and carbon inelastic scattering of 20 Mg were studied by reverse kinematics fordeducing the excitation energy of the ﬁrst 2+ state
20
Mg and the reduced transition probability
E(2+1 ) inB(E2).
A radioactive 20 Mg beam was produced by the fragmentation of a 24 Mg beam at 135 A MeV in 1.35-mmthick nickel target, and was isotopically separated using the RIKEN projectile-fragment separator (RIPS)in cooperation with the RF deﬂector.1) Particle identiﬁcation of the secondary beam was performed eventby-event by the Bρ-TOF-∆E method. Using the nickel
target instead of a 6-mm-thick beryllium target, thenumber of contaminant particles was greatly reduced
and the purity of 20 Mg was improved by a factor of
6. A further purity improvement of a factor of 3 wasachieved using the RF deﬂector. Typical 20 Mg-beam
intensity was 0.5 kcps, which was about 12% of the total secondary-beam intensity.
A lead target with a thickness of 226 mg/cm2 placedat the ﬁnal focus was bombarded by the 20 Mg beam.
The beam energy at the center of the target was
58 A MeV. The beam spot size and incident angle
were measured with two PPACs placed 1.50 and 1.20 m
upstream of the target. Scattered 20 Mg was measured
using nine silicon-counter telescopes arranged in a 3×3
matrix located 65 cm downstream of the target. Each
telescope consisted of six layers of ion-implanted silicon detectors with an eﬀective area of 50 × 50 mm2
and a thickness of 500 µm. For the ﬁrst and second layers, strip detectors with 5-mm strip pitch wereused for measuring the scattering angle of 20 Mg in thevertical and horizontal directions, respectively. The
scattered 20 Mg stopped at the fourth or ﬁfth layers.
Particle identiﬁcation of the scattered 20 Mg was performed by the ∆E-E method. Deexcitation γ rays
∗1

Department of Physics, Tohoku University
ATOMKI, Hungary∗3 Department of Physics, Rikkyo University∗4 Institut de Physique Nucléaire, France∗5 Department of Physics, Saitama University∗6 Department of Physics, Tokyo Institute of Technology∗7 Department of Physics, University of Tokyo∗8 Center for Nuclear Study, University of Tokyo∗9 High Energy Accelerator Research Organization (KEK)∗10 Department of Physics, Kyoto University∗11 Argonne National Laboratory, USA∗12 Department of Physics, Kyushu University∗2

58

were detected with an array of 68 NaI(Tl) scintillators (DALI)2) surrounding the target. Each scintillator crystal has a rectangular shape with dimensions of
6 × 6 × 12 cm3 . The energy resolution was measured
to be 9% (FWHM) for 0.661 MeV γ rays from a 137 Cs
source. Detection eﬃciency was measured for 137 Cs,
60
Co, and 22 Na calibrated sources, and the obtained
results agreed with the results of Monte Carlo simulations using GEANT3 within the errors.
Figure 1 shows the Doppler-corrected γ-ray energy spectrum measured in coincidence when bothbeam particles and reaction products were identiﬁed as
20
Mg. Only the events with the γ detection multiplicity equal to 1 were employed to obtain the spectrum.
The γ line at 1.61 ± 0.06 MeV was clearly observed forthe ﬁrst time. This γ line was also observed in the20
Mg+C reaction. It was tentatively assigned to the++transition of 2+
1 → 01 . The ﬁrst 2 energy was determined to be 1.61±0.06 MeV in the present experiment.
Further analysis of the data is in progress.

Fig. 1. Doppler-corrected γ energy spectrum measured incoincidence with 20 Mg. The solid curve represents thebest fit by simulated line shape (dashed curve) and exponential background (dotted curve).

References
1) K. Yamada et al.: RIKEN Accel. Prog. Rep. 35, 147(2002).
2) T. Motobayashi et al.: Phys. Lett. B 346, 9 (1995).

RIKEN Accel. Prog. Rep. 38 (2005)

Elastic resonance scattering of 23 Mg+p
T. Teranishi,∗1 S. Kubono,∗2 J. J. He,∗2 M. Notani,∗2 T. Fukuchi,∗2 S. Shimoura,∗2 S. Nishimura, M. Nishimura,
S. Michimasa, Y. Wakabayashi,∗1 N. Hokoiwa,∗1 Y. Gono,∗1 A. Odahara,∗3 H. Baba,∗4 J. Y. Moon,∗5
J. H. Lee,∗5 C. S. Lee,∗5 J. C. Kim,∗5 H. Ishiyama,∗6 Y. X. Watanabe,∗6 T. Hashimoto,∗7 T. Ishikawa,∗7
M. H. Tanaka,∗6 H. Miyatake,∗6 V. Guimarães,∗8 R. Lichtenthäler,∗8 H. Sato,∗9 T. Kawamura,∗9 and S. Kato∗9[unstable nuclei, nuclear astrophysics]24

Al levels above the proton threshold of Ex =1.871 MeV may play important roles in the astrophysical reaction of 23 Mg(p,γ)24 Al, which is one of the
breakout paths from the Ne-Na cycle.1) J π values have
not yet been precisely determined for many 24 Al levels. There are almost no experimental data of Γ for24
Al resonance levels.2) We performed an experimenton 23 Mg+p elastic resonance scattering, aiming at deducing new information on J π and Γ for the 24 Al levels.
The 23 Mg+p experiment was performed in inverse
kinematics with a secondary 23 Mg beam and a proton target. The 23 Mg beam was produced by the24
Mg(d,t)23 Mg reaction in inverse kinematics. The
primary 24 Mg beam was accelerated using an AVF
cyclotron up to 7.5 MeV/nucleon with an intensityof 60 pnA. The deuterium gas target had a thickness of 0.33 mg/cm2 and was conﬁned in a cell by
two Havar window foils of 2.2 µm. After the CRIB
separator,3,4) the 23 Mg secondary beam had an energy of 4.0 MeV/nucleon and an intensity of 3.2 ×
104 particles/sec.
A thick-target technique5,6) was used to measure theexcitation function eﬃciently. A polyethylene sheet of
8.2 mg/cm2 was set as a proton target. Due to theenergy-loss process of the beam in the target, a wide
center-of-mass energy (ECM ) range was scanned without changing the beam energy before the target. Whilethe beam particles were completely stopped in the target, most of the recoil protons went out from the target
with small energy losses. The recoil protons were detected by the two sets of silicon detectors at laboratory
angles of θLAB = 0◦ and 17◦ . Each set consisted of∆E and E layers with thicknesses of 75 and 1500 µm,
respectively. Protons were identiﬁed with the information of ∆E, E, and timing. The ECM and center-ofmass angle (θCM ) were determined by measuring theenergy and angle of protons.
Preliminary spectra of 23 Mg+p at θLAB = 0◦ and17◦ are shown in Fig. 1. The solid line represents the
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8
∗9

Fig. 1. Preliminary excitation functions for 23 Mg+p at
θLAB = 0◦ and 17◦ . The solid curves represent the crosssections deduced from the Coulomb and hard-spherescattering amplitudes.

cross sections deduced from the Coulomb and hardsphere scattering amplitudes. The deviation of the experimental cross sections from the solid line is seen ina region of ECM > 1.6 MeV both at 0◦ and 17◦ . These
deviation patterns at 0◦ and 17◦ are similar to eachother, indicating the presence of several resonance levels. The quantitative analysis of these patterns is inprogress. Certain J π values will be determined by Rmatrix analysis. The Γ for these levels will also be
evaluated for the ﬁrst time.
References
1) S. Kubono et al.: Nucl. Phys. A 588, 521 (1995), andreferences therein.
2) P. M. Endt: Nucl. Phys. A 633, 1 (1998).
3) T. Teranishi et al.: Nucl. Phys. A 718, 207c (2003).
4) S. Kubono et al.: Eur. Phys. J. A 13, 217 (2002).
5) K. P. Artemov et al.: Sov. J. Nucl. Phys. 52, 408 (1990).
6) S. Kubono: Nucl. Phys. A 693, 221 (2001), and references therein.

Department of Physics, Kyushu University
Center for Nuclear Study, University of Tokyo
Nishinippon Institute of Technology
Department of Physics, Rikkyo University
Department of Physics, Chung-Ang University, Korea
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Department of Physics, Tokyo University of Science
Department of Physics, University of São Paulo, Brazil
Department of Physics, Yamagata University

59

RIKEN Accel. Prog. Rep. 38 (2005)

Measurements of magnetic moments of 30 Al and 32 Al
D. Kameda,∗1 K. Asahi, H. Ueno, A. Yoshimi, G. Kijima,∗1 H. Miyoshi,∗1 K. Shimada,∗1 T. Haseyama,
D. Nagae,∗1 G. Kato,∗1 S. Emori,∗1 M. Tsukui,∗1 H. Watanabe,∗2 Y. Kobayashi, and M. Ishihara[NUCLEAR STRUCTURE, Neutron-rich isotopes, Spin polarization, β-NMR method]
We measured the magnetic moments of 30 Al(I π =3 , T1/2 = 3.60 s) and 32 Al(I π = 1+ , T1/2 = 33 ms) by
the β-NMR method with the spin-polarized radioactive nuclear beams which were produced in the RIKEN
Projectile-fragmentation Separator RIPS.
The average intensity for the primary beam of
95 A MeV 40 Ar17+ was 54 particle nA. The 30 Al fragments produced by use of a 0.13 g/cm2 thick nat Nb target were separated from other nuclides in RIPS. In order to obtain spin-polarized fragments, selections werealso made on the emission angle, θ = 1.3◦ –5.7◦ , andthe outgoing momentum, p = 12.4–12.7 GeV/c. In thecase of 32 Al, a 0.37g/cm2 thick nat Nb target was employed and a momentum region, p = 12.2–13.0 GeV/c,
was selected. The purities of the secondary beams were
93% for 30 Al and 86% for 32 Al.
The spin-polarized fragments were implanted in asingle crystal α-Al2 O3 (corundum) to which a static
magnetic ﬁeld B0 ≈ 0.5 mT was applied. The crystal
sample was mounted on a holder for which the angle
between the c-axis of the crystal and the B0 ﬁeld wasmaintained at (54 ± 1)◦ , the “magic angle” where thequadrupolar splitting for 30 Al and 32 Al in the crystal
vanishes. The holder temperature was maintained below 100 K so that a suﬃciently long spin-lattice relaxation time was achieved. β-rays from the stopper weredetected with counter telescopes consisting of threeplastic scintillators located above and below the stopper.
The obtained β-NMR spectra for 30 Al and 32 Al
are shown in Figs. 1 and 2, respectively. The vertical bars show statistical errors only. The horizontal bars indicate the frequency regions over which
the RF ﬁeld was swept. The solid circles represent
the centers of the individual frequency regions. In
Fig. 1 (2), a signiﬁcant asymmetry change is observed
at 3831 (7446) kHz with the deviation from zero by
4.0 (4.4) σ. Thus, the resonance frequencies for 30 Al
and 32 Al were obtained to be (3830.8 ± 20.7) kHz and(7445.7 ± 64.0) kHz, respectively. The errors indicatedhere are tentative ones which were determined fromthe width of the swept frequency. The magnetic moments obtained are |µ(30 Al)| = (3.012 ± 0.021)µN and|µ(32 Al)| = (1.959 ± 0.019)µN , where µN denotes thenuclear magneton. Fitting analyses for the spectra,
+

∗1
∗2

60

Department of Physics, Tokyo Institute of Technology
Department of Nuclear Physics, Australian National University, Australia

Fig. 1. β-NMR spectrum for 30 Al. The β-ray asymmetry
change in the β-ray up/down ratio is plotted against thefrequency regions over which the RF field was swept.

Fig. 2. β-NMR spectrum for 32 Al.

which are now in progress, would improve the accuracy of the tentative results.
A shell model calculation with the USD eﬀective interaction1) for sd-shell model space is in good agreement with the present results within 6%. On the other
hand, the magnetic moment of 30 Na, which has thesame neutron number as 32 Al, was found2) to be 23%
smaller than the shell model prediction using the USD
interaction. The present result shows sharp contrast
to the 30 Na result2) at the border of the “island of
inversion”3) where the N = 20 shell gap vanishes.
References
1) B. H. Wildenthal: Prog. Part. Nucl. Phys. 11, 5 (1984).
2) M. Keim et al.: Eur. Phys. J. A 8, 31 (2000).
3) E. K. Warburton et al.: Phys. Rev. C 41, 1147 (1990).

RIKEN Accel. Prog. Rep. 38 (2005)

Production of spin-polarized 33 Si beam for g -factor measurement
G. Kijima,∗1 K. Asahi, H. Ueno, D. Kameda,∗1 H. Miyoshi,∗1 A. Yoshimi, H. Watanabe,∗2 T. Haseyama,
M. Uchida,∗1 K. Shimada,∗1 D. Nagae,∗1 G. Kato,∗1 S. Emori,∗1 M. Tsukui,∗1 S. Oshima,∗1 M. Takemura,∗1
T. Arai,∗1 and Y. Kobayashi

NUCLEAR STRUCTURE, 33 Si, β-NMR method, g-factor
It was revealed in our earlier study that spin polarization is produced as a function of the emission angle
θL and momentum pF of fragments.1,2) Taking advantage of spin-polarized radioactive-isotope beams in the
β-NMR method,3) the nuclear moments of light unstable nuclei have been determined.4) In this method,
however, g-factor search could not be performed separately from the production of spin polarization in principle. For the g-factor measurement of 33 Si, the parameter sets of θL and pF have been investigated for the
production of spin-polarized 33 Si fragments in a wide
range of g factor values prior to the g-factor determination.
A beam of 33 Si was produced from the fragmentation of an 40 Ar projectile at an energy of 95 A MeV
on a 385 mg/cm2 -thick Nb target. The 33 Si beam wasisotope-separated using a projectile-fragment separator RIPS with its θL and pF selected accordingly. The
33
Si beam was then introduced to the final focus andimplanted into a 0.3 mm-thick α-Al2 O3 single-crystal
stopper in a β-NMR apparatus located at the final focus of RIPS. The single crystal was cut so that thec-axis of the hexagonal crystal structure was oriented
parallel to its surface. The stopper was kept undervacuum and oriented at the magic angle (54.7◦ ) withrespect to an external magnetic field B0 , where thequadrupolar level splitting of the magnetic sublevels
vanishes. A B0 of ∼ 700 mT was applied in order topreserve the spin polarization.5) A radio-frequency oscillating field B1 ∼ 1 mT was applied to the stopperin the direction perpendicular to B0 . The α-Al2 O3
stopper was cooled to a temperature of T < 100 K,
where a long spin-lattice relaxation time is expected6)
compared with its β-decay lifetime τ = 8.91 sec. We
employed β-NMR measurements3) with the adiabatic
fast passage (AFP) technique.7) In this method, theresonance is observed through a change in the β-ray
asymmetry AP , where A is the β-decay parameter and
P the spin polarization.
An obtained NMR spectrum is shown in Fig. 1,
where all data obtained with various parameter setsof θL and pF are plotted. The deviation of up/down
ratios, which are divided by those obtained without
B1 , from unity indicates the occurrence of the spin alteration by the AFP-NMR. Within a search region of
the frequency range 3501.2 – 4598.0 kHz, we found that∗1
∗2

Department of Physics, Tokyo Institute of Technology
Department of Nuclear Physics, Australian National University, Australia

two data points showed substantialy high AP values of∼ 0.2% with 3.3σ and 4.2σ statistics as depicted byhole circles in Fig. 1. The left (right) data point was
obtained for the 33 Si fragments produced at θL = 1.3◦
−5.7◦ (0.5◦ −5.7◦ ) and pF = 12.8 − 13.6(13.3 − 13.7)
GeV/c. The two data points exhibit the same signand similar magnitudes of polarization. These facts
indicate that they have a resonance frequency in thecommon frequency region. These asymmetry changes,
however, could not be confirmed in a precision measurement. Two factors can be considered to accountfor this imprecison:i)

A resonance frequency was not included in thetwo data points and 33 Si was not spin-polarized.
Two data points accidentally deviated fromunity with 3.3σ and 4.2σ statistics.
ii) It was found after the experiment that B0 was
not completely stabilized due to trouble in thecurrent stabilization system of the power supply.
The adiabatic conduction for the spin reversal
was not met in the AFP-NMR.

The latter would be reasonable, but it could not be
proved with only the present data. An experiment forthe confirmation of the observed 33 Si spin polarizationand its g-factor measurement are under preparation.

Fig. 1. Obtained β-NMR spectrum for 33 Si in various parameter sets of θL and pF . The data points are accompanied by the statistical errors and widths of swept
frequency in the AFP-NMR. For details, see the text.

References
1) K. Asahi et al.: Phys. Lett. B 251, 488 (1990).
2) H. Okuno et al.: Phys. Lett. B 335, 29 (1994).
3) K. Sugimoto et al.: J. Phys. Soc. Jpn. 21, 213 (1966).
4) K. Asahi et al.: Nucl. Phys. A 704, 88c (2002).
5) J. W. Hugg: Phys. Rev. C 30, 1328 (1984).
6) R. L. Mieher: Phys. Rev. Lett. 4, 57 (1960).
7) A. Abragam: The Principle of Nuclear Magnetism(Clarendon, Oxford, 1961).

61

RIKEN Accel. Prog. Rep. 38 (2005)

Investigation of first excited state in 27 P for astrophysical interest
Y. Togano,∗1 T. Gomi,∗1 T. Motobayashi, Y. Ando,∗1 N. Aoi, H. Baba,∗1 K. Demichi,∗1 Z. Elekes,
N. Fukuda, Zs. Fülöp,∗2 U. Futakami,∗1 H. Hasegawa,∗1 Y. Higurashi, K. Ieki,∗1 N. Imai, M. Ishihara,
K. Ishikawa,∗3 N. Iwasa,∗4 H. Iwasaki,∗5 S. Kanno,∗1 Y. Kondo,∗3 T. Kubo, S. Kubono,∗5 M. Kunibu,∗1
K. Kurita,∗1 Y. U. Matsuyama,∗1 S. Michimasa,∗5 T. Minemura, M. Miura,∗3 H. Murakami,∗1 T. Nakamura,∗3
M. Notani,∗5 S. Ota,∗6 A. Saito,∗1 H. Sakurai,∗7 M. Serata,∗1 S. Shimoura,∗5 T. Sugimoto,∗3 E. Takeshita,∗1
S. Takeuchi, K. Ue,∗7 K. Yamada,∗1 Y. Yanagisawa, K. Yoneda,∗8 and A. Yoshida
208Pb(27 P,p26 Si)208 Pb, Coulomb dissociation, Nuclear astrophysics
The Coulomb dissociation of 27 P has been studied
to investigate the 26 Si(p,γ)27 P reaction. The gamma
decay width of the first excited state in 27 P was extracted for astrophysical interest.
The 26 Si(p,γ)27 P reaction is suggested to be one of
the important reactions in the rp process.1) In particular, this reaction is on the path of the reaction flowof the rp process in X-ray bursts.2) In extremely hightemperature and density environments such as X-ray
bursts and novae, resonances below 1 MeV play an important role. The resonance structure of 27 P was once
studied via the 28 Si(7 Li,8 He)27 P reaction.3) However,there is no experimental information of the strength on
the resonances. Here, we report on the gamma decay
width, which is relevant to the strength of the resonances, of the first excited state in 27 P.
An experiment was performed at the RIPS beam linein the RIKEN Accelerator Research Facility. The secondary beam of 27 P at 57 MeV/nucleon was producedby the fragmentation of the 115-AMeV 36 Ar beam on
a 9 Be target. The 27 P beam bombarded a 125 mg/cm3
thick natural Pb target. The details of the experimental setup are described in Ref. 4.
Supposing the spin and parity of the first excitedstate in 27 P is 3/2+ from the level scheme of the mirror nucleus 27 Mg, the transition between the first excited state and the ground state (1/2+ ) is inducedby M1/E2 multipolarities. Since the E2 component
was strongly enhanced in the Coulomb dissociation,5)
the experimental cross section may be exhausted via
the E2 excitation. To extract the total gamma decay width, the M1 component was estimated using themixing ratio E2/M1 = 0.048 from the mirror transitionin 27 Mg.6) The gamma decay width of the first excitedstate was determined preliminarily to be 0.36 meV withan uncertainty of 15%. This value is ten times smaller
than that estimated on the basis of a shell model calculation by Caggiano et al.3) This indicates that the
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8

62

Rikkyo University
Institute of Nuclear Research, ATOMKI, Hungary
Tokyo Institute of Technology
Tohoku University
Center for Nuclear Study, University of Tokyo
Kyoto University
University of Tokyo
National Superconducting Cyclotron Laboratory, Michigan
State University, USA

26

Si(p,γ)27 P reaction does not contribute significantly
to the amount of 26 Al in novae.3)
The gamma decay width depends on the mixing ratio. The relationship between the gamma decay widthand E2/M1 mixing ratio is presented in Fig. 1. The
solid and dashed lines represent our result and marginof experimental error, respectively. The closed circle
represents the value obtained with the E2/M1 mixing
ratio of the first excited state in 27 Mg corresponding to
the result mentioned above (0.36 meV). The diamondindicates the value obtained with the E2/M1 mixing
ratio calculated using a simple single-particle model.7)
The dot-dashed line denotes the gamma decay width
calculated by the shell model.3) The upper and lower
limits of the gamma decay width are determined tobe 29 meV and 1.6×10−2 meV, assuming the decay occurs with pure M1 and E2 multipolarities, respectively.
Further analysis is now in progress.

Fig. 1. Relationship between gamma decay width andE2/M1 mixing ratio.

References
1) H. Herndl et al.: Phys. Rev. C 52, 1078 (1995).
2) H. Schatz et al.: Nucl. Phys. A 718, 247c (2003).
3) J. A. Caggiano et al.: Phys. Rev. C 64, 025802 (2001).
4) Y. Togano et al.: RIKEN Accel. Prog. Rep. 37, 69(2004).
5) T. Motobayashi et al.: Phys. Rev. Lett. 73, 2680 (1994).
6) M. J. A. Voigt et al.: Nucl. Phys. A 186, 365 (1972).
7) A. Bohr and B. R. Mottelson: Nuclear Structure, Vol.1(World Scientific, Singapore, 1988).

RIKEN Accel. Prog. Rep. 38 (2005)

Study of astrophysically important resonance states in 26 Si and 27 P
using radioactive ion beams
J. Y. Moon,∗1 C.-S. Lee,∗1 J.-H. Lee,∗1 C. C. Yun,∗1 J. C. Kim,∗2 M. Youn,∗2 S. Kubono,∗3 T. Teranishi,∗4J. J. He,∗3 M. Notani,∗3 S. Nishimura, M. Kurata-Nishimura, S. Kato,∗5 V. Guimarães,∗6 andR. F. Lichitenthaler∗6
Nucleoastrophysics, radioactive ion beam, 26 Si, 27 P
As described in our previous report,1) spectroscopic
properties, such as excitation energy, decay width andspin-parity of levels above the proton threshold in 26 Si
and 27 P, are very crucial to determining the production
rate of 26 Al (g.s.) in stellar sites under the explosivehydrogen burning stage, which is a source of cosmic
gamma-rays of 1.809 MeV. We performed an experiment on 25 Al + p and 26 Si + p elastic scatterings to
obtain such information. In this report, preliminary
results of R-matrix analysis are presented.
This experiment has been carried out with theradioactive beams obtained using the CNS radioactive ion beam separator (CRIB)2,3) and thick target
method.4,5) A 24 Mg8+ primary beam accelerated by
the RIKEN AVF cyclotron (K = 70) was used to bombard a 3 He gas target at 7.434 A MeV. The thickness ofthe 3 He gas target was 0.32 mg/cm2 . With 3 He(24 Mg,np)25 Al and 3 He(24 Mg, n)26 Si, two kinds of radioactive beam of 25 Al and 26 Si were produced and used formeasuring 1 H(25 Al, p)25 Al and 1 H(26 Si, p)26 Si elastic
scatterings, respectively. More details of the experimental setup were described in Ref. 1.
Using a (CH2 )n target whose thickness of 8.13
mg/cm2 was suﬃcient to stop the secondary
beams, namely, 25 Al of 3.4407 A MeV and 26 Si of
3.9575 A MeV, we could scan up to Ex = 8.8243 MeV
for 26 Si and Ex = 4.7109 MeV for 27 P above the proton threshold. The energy resolutions of the 0◦ - and17◦ -detection systems1) that were used to detect therecoiled protons were 36 keV and 53 keV (FWHM) in
the center of mass (C.M.), respectively. Figure 1 shows
the proton excitation function for each case, obtainedat 0◦ corresponding to 180◦ in the C.M. frame where
the interference patterns of the potential and resonancescatterings are signiﬁcant. The energy region above
EC.M. = 2.8 MeV was omitted in the analysis, because
there existed a large proton contaminant from the elastic scattering due to hydrogen atoms in the mylar layers of a PPAC in the F2 chamber. In the 26 Si + p
elastic scattering, R-matrix analysis is performed using the code SAMMY M6-beta6) to determine the en∗1
∗2
∗3
∗4
∗5
∗6

Department of Physics, Chung-Ang University, Korea
Department of Physics, Seoul National University, Korea
Center for Nuclear Study, Graduate School of Science, University of Tokyo
Department of Physics, Kyushu University
Department of Physics, Yamagata University
Instituto de Fı́sica, Universidade de São Paulo, Brazil

Fig. 1. Elastic scattering spectra obtained from this work.
In the lower figure, the solid line represents the casewith a state at Ex = 3.073 MeV in R-matrix analysis
and the dashed line for the case without it. See text for
details.

ergy, decay width and spin-parity of resonance states.
The energy and decay width are used as varied parameters. A small bump (a) at approximately EC.M. =2.2 MeV is assumed to be due to two resonance statesfrom the comparison of our results with those of theshell model and with the level structure of mirror nucleus 27 Mg (Table 1). The shell model calculation was

Table 1. Resonance states in 27 P determined in this work
(tentatively) and their comparison with those determined using 27 Mg and shell model calculations.
Jπ
7/2+
3/2+
3/2−

27

Mg
3.109
3.109
3.560

Shell model
3.150
3.163

This work§
3.073(202)
3.109(66)3.323(33)§

Excitation energy in MeV and fitting uncertainty shownin this work.

63

carried out in the sd model space with the Wildenthal(USD) Hamiltonian7) using the code Oxbash.8) From
the R-matrix ﬁtting based on this assumption and preliminary analysis, the two states of Ex = 3.073 MeV
and Ex = 3.109 MeV in 27 P whose excitation energy
is Ex = EC.M. + 0.897 MeV are assigned with spinparities of Jπ = 7/2+ and 3/2+, respectively, and thestate of Ex = 3.323 MeV assigned with Jπ = 3/2−
contributed to the bump (b). It should be noted thatthe reduced χ2 (χ2 divided by the number of data) increases from 0.88 to 1.030 when only one resonance isassumed at approximately Ex = 3.1 MeV. In the caseof 25 Al + p elastic scattering, interference patterns arealso found. Detailed analysis is being performed toclarify the above resonance states.

64

References
1) J. Y. Moon et al.: RIKEN Accel. Prog. Rep. 37, 65(2004).
2) T. Teranishi et al.: Phys. Lett. B 556, 27 (2003).
3) Y. Yanagisawa et al.: Nucl. Instrum. Methods Phys.
Res. A 539, 74 (2005).
4) K. P. Artemov et al.: Sov. J. Nucl. Phys. 52, 408 (1990).
5) S. Kubono: Nucl. Phys. A 693, 221 (2001), and references therein.
6) N. M. Larson: ORNL/TM-9179/R5, Oak Ridge National Laboratory (2000).
7) B. H. Wildenthal: Prog. Part. Nucl. Phys. 11, 5 (1984).
8) B. A. Brown et al.: MSU-NSCL report number 1289
(1988).

RIKEN Accel. Prog. Rep. 38 (2005)

Systematic behavior of B(E2) for Tz = ±1 even-even nuclides studied
by Coulomb excitation of 46 Cr, 50 Fe, and 54 Ni
K. Yamada, T. Motobayashi, N. Aoi, H. Baba,∗1 K. Demichi,∗2 Z. Elekes,∗3 J. Gibelin,∗4 T. Gomi,
H. Hasegawa,∗2 N. Imai,∗5 H. Iwasaki,∗6 S. Kanno,∗2 T. Kubo, K. Kurita,∗2 Y. U. Matsuyama,∗2
S. Michimasa, T. Minemura,∗5 M. Notani,∗7 T. K. Onishi,∗6 H. J. Ong,∗6 S. Ota,∗8
A. Ozawa,∗9 A. Saito,∗1 H. Sakurai,∗6 S. Shimoura,∗1 E. Takeshita,∗2 S. Takeuchi,
M. Tamaki,∗1 Y. Togano,∗2 Y. Yanagisawa, K. Yoneda,∗10 and I. Tanihata∗7[Nuclear structure, B(E2), Coulomb excitation, Matrix element]
The proton-rich 46 Cr, 50 Fe, and 54 Ni nuclei werestudied by intermediate-energy Coulomb excitation inorder to investigate the evolution of the nuclear collectivity at the beginning of the pf shell as reported pre+46
Cr, 50 Fe,
viously.1) The B(E2; 0+g.s. → 21 ) values of54
and Ni were extracted from the Coulomb excitation
cross sections with the help of DWBA analysis to be
929 ± 199 e2 fm4 , 1359 ± 261 e2 fm4 , and 590 ± 168
e2 fm4 , respectively. The excitation energy E(2+ ) was
also determined for the first 2+ excited state in 54 Ni to
be 1374 ± 30 keV. The complete systematics of B(E2)and E(2+ ) for the Tz = ±1 even-even nuclides up to
Z = 28 have been established by the present study.
The proton and neutron matrix elements, |Mp | and|Mn |, were separately extracted from the B(E2) values by combining the ones known for their mirror nuclei,2) for which we used the Bernstein’s mirror nucleus
method,3) which is based on the equality between Mp
and Mn in the mirror pair under the assumption of
isospin symmetry. The resultant |Mp | values are respectively 4.4 ± 0.5 W.u., 5.0 ± 0.5 W.u., and 3.1 ±0.4 W.u. for 46 Cr, 50 Fe, and 54 Ni, while the |Mn | values were extracted to be 4.4 ± 0.1 W.u., 4.4 ± 0.1
W.u., and 3.2 ± 0.1 W.u., respectively.
The double ratio (|Mn |/|Mp |)/(N/Z) is a measureof the collectivity of the 2+
1 states. In even-even nuclei in which both proton and neutron shells are open,
the ratio is generally close to unity, while nuclei withclosed shells systematically deviate from unity. Figure 1 shows the ratios for all Tz = −1 even-even nuclides in the Z = 10–28 region. The results obtained
for both 46 Cr and 50 Fe are close to unity and are consistent with the picture of a collective nucleus. The
ratio for 54 Ni, which is close to unity, indicates the
weakness of the Z = 28 shell closure.
∗1

Center for Nuclear Study, University of Tokyo
Department of Physics, Rikkyo University∗3 Institute of Nuclear Research of the Hungarian Academy of
Sciences, Hungary∗4 Institut de Physique Nucléare, France∗5 High Energy Accelerator Research Organization∗6 Department of Physics, University of Tokyo∗7 Argonne National Laboratory, USA∗8 Department of Physics, Kyoto University∗9 Department of Physics, University of Tsukuba∗10 National Superconducting Cyclotron Laboratory, Michigan
State University, USA

Fig. 1. The ratio of |Mn | and |Mp | normalized by N/Z for
Tz = −1 even-even nuclides in the Z = 10–28 region.

In Fig. 1, the ratios are compared with theoreticalpredictions from the conventional shell-model calculations using the USD interaction for the sd -shell region4) and the GXPF1 interaction for the pf -shell region5) (dashed lines) and from the deformed HartreeFock + BCS calculation6) using the SIII interaction(dot-dashed line). The experimental results exhibit
smaller extents of single-particle natures comparedwith the shell-model predictions in the vicinity of theshell closures 20 and 28, suggesting the importance ofcollective aspects which should be taken into account.
On the other hand, the behavior of the experimental
data is well reproduced by the deformed HF + BCS
prediction. However, this prediction considerably underestimates the amplitude of the matrix elements: forexample, the predicted |Mp | values are smaller by afactor of approximately 20 for 38 Ca and 42 Ti. The
present result requires a more elaborate treatment of
the nuclear collectivity in this mass region.

∗2

References
1) K. Yamada et al.: RIKEN Accel. Prog. Rep. 37, 76(2004).
2) S. Raman et al.: At. Data Nucl. Data Tables 78, 1(2001).
3) A. M. Bernstein et al.: Phys. Rev. Lett. 42, 425 (1979).
4) B. A. Brown et al.: Phys. Rev. C 26, 2247 (1982).
5) M. Honma et al.: Private communication.
6) H. Sagawa et al.: Private communication.

65

RIKEN Accel. Prog. Rep. 38 (2005)

Proton inelastic scattering on 74 Ni
S. Kanno,∗1 N. Aoi, W. F. Mueller,∗2 H. Sakurai,∗3 D. Bazin,∗2 M. D. Bowen,∗2 C. M. Campbell,∗2
J. M. Cook,∗2 D.-C. Dinca,∗2 A. Gade,∗2 T. Glasmacher,∗2 H. Iwasaki,∗3
T. Kubo, T. Motobayashi, T. Nakamura,∗4 H. Olliver,∗2 H. Suzuki,∗3
S. Takeuchi, J. R. Terry,∗2 and K. Yoneda∗2
NUCLEAR STRUCTURE, 74 Ni(p,p’γ), 104 MeV/u, Inelastic Scattering, Unstable nuclei
Proton inelastic scattering on the very neutronrich nucleus 74 Ni was studied using a liquid hydrogen target (LH2 1) ) and a radioactive beam of 74 Ni at
104 MeV/nucleon.
Among Ni isotopes, the excitation energies of theﬁrst 2+ states (Ex (2+ )’s) are known for the nuclei
lighter than 72 Ni. They are higher than those in theneighboring nuclei, reﬂecting the magicity at Z=28.
In the present experiment, Ex (2+ ) and the deformation parameter of a more neutron-rich Ni isotope 74 Ni
is measured by proton inelastic scattering aiming at
exploring the evolution of the magicity at Z=28 in avery neutron-rich region.
The proton inelastic scattering with a LH2 target
has the highest sensitivity to the present experiment.
One of the advantages is the large number of nuclei inthe target material. The other is the low backgrounddue to the absence of γ rays originating from the target nuclei. These advantages enable us to perform theexperiment with an extremely weak secondary beamof 74 Ni.
The experiment was performed at the National
Superconducting Cyclotron Laboratory (NSCL) at
Michigan State University. The 74 Ni nucleus was produced by the projectile fragmentation of a 86 Kr primary beam (140 MeV/nucleon, 20 pnA) on a 9 Be production target (188 mg/cm2 ). The fragments were collected and analyzed with the A1900 fragment separator2) and transmitted to the S800 spectrograph.3)
The 74 Ni intensity was typically 0.5 particle/sec witha purity of 0.73%. The other nuclei in the secondary
beam and their intensities were as follows : 73 Ni (0.3),
75
Cu (7.1), 76 Cu (3.5), 77 Zn (16.7), 78 Zn (9.1), 79 Ga(12.7), 80 Ga (5.7), 81 Ge (0.1) and 82 Ge (0.5), where thevalues in the parentheses are the intensities in the unitsof count/sec. The LH2 target was placed at the target position of S800 which was tuned to the focusing
mode. The LH2 target system was previously developed at Kyushu-Rikkyo-RIKEN. We used aluminumfor the cell window for instead of haver foil to increase
the number of fully stripped particles that reach the
focal plane of S800.
The plastic scintillator at the extended focal planeof A1900 is used for the time-of-ﬂight (TOF) start sig∗1
∗2
∗3
∗4

66

Rikkyo University
Michigan State University, USA
University of Tokyo
Tokyo Institute of Technology

nal. At the object point of S800, PIN Si detectors
for determinig the energy-loss (∆E) of the secondary
beam were located, and at the focal plane, a pair of
Cathode Readout Drift Chambers (CRDC’s) for determining Bρ, an ion-chamber with 140 Torr P10 gas
for determining ∆E, and three plastic scintillators fordetermining TOF-stop signal were placed in vacuum.4)
The high resolving power of these detectors enable us
to distinguish the isotopes of A ∼ 74.
The particle identiﬁcation of the secondary beam
was carried out event-by-event using the TOF and ∆Eof PIN Si. A ﬂight path length of 60 m is suﬃcient todistinguish 74 Ni nuclei from other beam fragments.
Scattered 74 Ni nuclei were detected by the ionchamber and CRDCs. We obtained the atomic number(Z) of the scattered particles from TOF and ∆E of theion-chamber. Using this Z-gate, we obtained the mass
number (A) from TOF and Bρ.
An array of 21 NaI(Tl) scintillators (the APEX array5) ) surrounded the target for detecting γ rays. Eachscintillator has a length of 55 cm with a trapezoidal
cross section and a height of 6 cm and a width of 5 or
7 cm. Three of the original 24 NaI(Tl) detectors were
removed to allow the insertion of the LH2 target fromthe top. Two photomultiplier tubes were optically coupled to each scintillator. Both the interaction point Xγand energy Eγ can be deduced from the output signals
from the pair of photomultiplier tubes. Since Xγ isused for event-by-event Doppler-shift correction of theγ rays from the excited 74 Ni moving with v/c ≈ 0.44,
the position, energy and eﬃciency calibrations of each
NaI(Tl) scintillator were made using standard 22 Na,
60
Co and 137 Cs sources.
Excitation to the 2+ state was identiﬁed by measuring the de-excitation γ rays in coincidence with theincoming and scattered 74 Ni ions. Further analysis are
now in progress.
References
1) H. Akiyoshi et al.: RIKEN Accel. Prog. Rep. 32, 167(1999).
2) D. J. Morrissey et al.: Nucl. Instrum. Methods Phys.
Res. B 204, 90 (2003).
3) D. Bazin et al.: Nucl. Instrum. Methods Phys. Res. B
204, 629 (2003).
4) J. Yurcon et al.: Nucl. Instrum. Methods Phys. Res. A
422, 291 (1999).
5) B. C. Perry et al.: Nucl. Instrum. Methods Phys. Res.
A 505, 85 (2003).

RIKEN Accel. Prog. Rep. 38 (2005)

Excitation function measurement of neutron-rich Ti isotope bysecondary fusion reaction
M. Niikura,∗1 E. Ideguchi,∗1 T. Fukuchi,∗1 H. Baba,∗1 N. Hokoiwa,∗2 C. Ishida,∗3 H. Iwasaki,∗4 T. Koike,∗5
T. Komatsubara,∗6 T. Kubo, M. Kurokawa, S. Michimasa, K. Miyakawa,∗6 K. Morimoto, T. Ohnishi, S. Ota,∗7
A. Ozawa,∗6 S. Shimoura,∗1 T. Suda, M. Tamaki,∗1 I. Tanihata,∗8 Y. Wakabayashi,∗2 and K. Yoshida
NUCLEAR REACTION, 9 Be(46 Ar, xn)55−x Ti, Unstable nuclei, Fusion reaction
We have studied high-spin states of 50 Ti in search
for a well-deformed rotational band due to the presence of deformed shell gaps1) in N = 28 and Z = 22.
Excited states in 50 Ti were previously studied using
the 48 Ca (α, 2n) 50 Ti reaction2) ; however, no rotational
bands were observed. Since deformed collective states
may approach yrast in higher excited states, it is necessary to populate spin states higher than those in aprevious study. This can be achieved by heavy-ion
fusion reactions, but the lack of beam and target combinations with stable isotopes has prevented experimental studies thus far. The usage of neutron-richradioactive (RI) beams can relax this experimental
constraint and enables the investigation of high-spinin the secondary fusion reacstates in 50 Ti populatedtion 9 Be 46 Ar, xn 50−x Ti. We have measured the excitation function of Ti isotopes produced by this reaction, in order to determine the optimum beam energy
for producing high-spin states in 50 Ti at a maximum
cross section.
The experiment was performed at the RIPS facility
in RIKEN.3) A low-energy 46 Ar beam was produced byfragmentation using a 48 Ca primary beam, and its energy was reduced to ∼6 MeV/nucleon using degraders
placed at the first (F1) and second (F2) focal planes.
The secondary beam was transported to the final (F3)
focal plane, where a 10-µm thick 9 Be target was placed
for the fusion reaction. The incident beam energy
was measured event-by-event by TOF deduced fromthe timing information of a plastic scintillator placed
at F2 and PPAC’s placed at F3. Due to the energy
struggling in the degraders and the beam-line detectors, the energy-broadened beam of 2–7 MeV/nucleon
at the center of the target was obtained.
Gamma rays from the excited states of the reaction
products 49-52 Ti were detected by the GRAPE system.4) We have successfully observed high-spin statesin 50 Ti3) and confirmed the known γ rays de-excitedfrom the first excited states: 1539, 1549, 1432, and
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8

Center for Nuclear Study, University of Tokyo
Department of Physics, Kyushu University
Department of Physics, Royal Institute of Technology,
SwedenDepartment of Physics, University of Tokyo
Department of Physics, Tohoku University
Institute of Physics, University of Tsukuba
Department of Physics, Kyoto University
Argonne National Laboratory, USA

1051 keV for 49-52 Ti, respectively.2,5–7) Based on theassumption that all γ-ray cascades decay through thesetransitions, their relative γ-ray yields normalized bybeam intensities are proportional to the production
cross section of each isotope. Figure 1 (b) shows therelative γ-ray yields gated using each incident beamenergy.
In Fig. 1 (a), the results of a statistical model calculation using the CASCADE code8) are shown. The
calculated production cross section compares well withthe peak beam energy and the trend of the measured
excitation function for the 9 Be 46 Ar, 5n 50 Ti reaction.
By taking into account the angular momentum inthe reaction as well as the excitation function, the optimum energy for producing the high-spin states in 50 Ti
was estimated to be ∼4.5 MeV/nucleon. Further analysis is now in progress.

Fig. 1. Calculated (a) and measured (b) excitation functions of Ti isotopes.

References
1) E. Ideguchi et al.: Phys. Rev. Lett. 87, 222501 (2001).
2) J. Styczen et al.: Nucl. Phys. A 327, 295 (1979).
3) E. Ideguchi et al.: RIKEN Accel. Prog. Rep. 38, 72(2005).
4) S. Shimoura: Nucl. Instrum. Methods Phys. Res. A
525, 188 (2004).
5) M. Behar et al.: Nucl. Phys. A 366, 61 (1981).
6) S. E. Arnell et al.: Phys. Scr. 6, 222 (1972).
7) R. V. F. Janssens et al.: Phys. Lett. B 546, 55 (2002).
8) F. Pühlhofer: Nucl. Phys. A 280, 267 (1977).

67

RIKEN Accel. Prog. Rep. 38 (2005)

Search for high-spin isomers in N = 51 isotones
Y. Wakabayashi,∗1,∗2 A. Odahara,∗3 Y. Gono, T. Fukuchi,∗2 S. Kubono,∗2 T. Teranishi,∗1 S. Ota,∗4
H. Yamaguchi,∗2 A. Saitoh,∗2 E. Ideguchi,∗2 S. Nishimura, J. J. He,∗2 H. Fujikawa,∗2
G. Amadio,∗2 M. Notani,∗5 Y. Yanagisawa, S. Michimasa, S. Shimoura,∗2
H. Watanabe,∗6 T. Kishida, H. Baba,∗2 and M. Kurata-Nishimura[High-spin isomer, γ-γ Coincidence, Unstable nuclear beams]
High-spin isomers are known in N = 83 isotones
systematically.1) They are considered to be shape isomers. In order to search for the same type of isomers inother mass regions, we selected N = 51 isotones whichhave similar single-particle orbits near the Fermi levelto those of N = 83 isotones.1)
We developed a 17 N secondary beam using the lowenergy radioactive-isotope beam separator (CRIB)2) of
the Center for Nuclear Study, University of Tokyo, for
high-spin isomer search in N = 51 isotones. Since
the nuclei with Z < 40 of N = 51 isotones are close
to the stability line, they can only be produced bylight-ion-induced reactions such as (p,α,Xn) by which
it is diﬃcult to produce high spin states of these nuclei. Therefore, it is eﬀective to use radioactive-isotope
beams. By means of the γ-ray spectroscopy method,high-spin isomers in 90 Y, 89 Sr and 88 Rb were searchedfor.
The experiment for isomer search was performed in
Sep. 2003 using CRIB. In this experiment, seven γ raysfrom 92,93 Nb produced by the secondary fusion reactions of 82 Se(17 N, 7n,6n) 92,93 Nb have been observed.
However, those of the relevant nuclei, such as those of
90
Y, which have production cross sections smaller thanthose of 92,93 Nb by one order of magnitude, could not
be observed. This is because the background level ofthe amount of thermal-neutron capture γ rays was 200
times higher than the expected counts of peak area
coming from the relevant nuclei, such as a 1535 keV
γ ray of 90 Y. Therefore, it is essential to reduce thethermal-neutron capture γ rays.
A test experiment for isomer search was performed
in May 2004. A 9 Be primary target of 2.3 mg/cm2 wasbombarded by an 18 O8+ primary beam of 126 MeV toobtain a 17 N beam. The beam current was 0.4 pµA
at the primary target position. A PPAC was set at adispersive focal plane (F1) for beam monitoring. Another PPAC and a Si detector of 1.5 mm thickness were
installed for particle identiﬁcation at an achromatic focal plane (F2). A PPAC and a Si detector were also
placed just upstream and downstream of a 82 Se sec∗1
∗2
∗3
∗4
∗5
∗6

68

Department of Physics, Kyushu University
Center for Nuclear Study, University of Tokyo
Nishinippon Institute of Technology
Department of Physics, Kyoto University
Physics Division, Argonne National Laboratory, USA
Department of Nuclear Physics, The Australian National
University, Australia

ondary target of 4.9 mg/cm2 , respectively, to separate
the secondary fusion reaction products from the 17 N
beam. This separation could be achieved by the particle identiﬁcation performed using energy signals of
the Si detector and time information between the signals from F3PPAC and the Si detector. Two clover Ge
detectors were set at 40 mm from the 82 Se secondary
target to measure γ rays emitted from the secondary
fusion reaction products.
Figure 1 shows time spectra between F3PPAC and
Ge detectors. Spectrum (a) was obtained without any
gate. Kinetic energies of recoiling fusion products arelower than 15 MeV. Therefore, spectrum (b) was obtained by setting a gate for this region of the Si energy spectrum. The time relations between signals
from F3PPAC and the Si detector could provide an
additional condition to select events related to the secondary fusion reaction products. The time period corresponding to those reaction products is that obtainedby setting a gate for a part lower than 15 MeV of the
Si energy spectrum. Spectrum (c) was obtained by
setting gates for both the Si energy spectrum and thetime spectrum between F3PPAC and the Si detector
selected under the gating condition mentioned above.
They indicate that the peak to background ratio has
been greatly improved by adding gate conditions. Consequently, the relevant γ rays can be measured using
the present setup.

Fig. 1. Time spectra between F3PPAC and Ge detectors.
Gating conditions of spectra (a), (b) and (c) are givenin the text.

References
1) Y. Gono et al.: Eur. Phys. J. A 13, 5 (2002), and references therein.
2) S. Kubono et al.: Eur. Phys. J. A 13, 217 (2002), andto be published in Nucl. Instrum. Methods Phys. Res.
B.

RIKEN Accel. Prog. Rep. 38 (2005)

Experiments on synthesis of isotope 277 112 by 208 Pb + 70 Zn reaction
K. Morita, K. Morimoto, D. Kaji, T. Akiyama,∗1 S. Goto,∗2 H. Haba, E. Ideguchi,∗3 H. Koura,∗4 H. Kudo,∗2
T. Ohnishi, A. Ozawa,∗5 T. Suda, K. Sueki,∗5 H. Xu,∗6 T. Yamaguchi,∗1 A. Yoneda,
A. Yoshida, and Y.-L. Zhao∗7
277

112, production and decay, gas-ﬁlled recoil ion separator
We studied isotope 277 112 using the 208 Pb(70 Zn, n)
reaction, as an extension of the previous studies on271
Ds (Z = 110)1) and 272 Rg (Z = 111).2) Previously,
the isotope was studied by Hofmann et al.,3) where
only two decay chains originating from 277 112 were reported. Therefore, it is important to conﬁrm these
events. During the irradiation of 208 Pb targets by 70 Zn
projectiles, we observed two decay chains that can be
assigned to subsequent decays originating from 277 112.
The result has provided a conﬁrmation of the discovery
of 277 112 and its daughter nucleus 273 Ds.
A 70 Zn ion beam of 349.5 MeV was extracted fromRILAC. The absolute accuracy of the beam energy
was ±0.6 MeV. A typical beam intensity on the target
was 1.7 × 1012 s−1 . Targets were prepared by vacuum
evaporation of 208 Pb, enrichment 98.4%, onto carbon
backing foils of 30 µg/cm2 thickness. The thickness of
the lead layer was about 450 µg/cm2 . The lead layer
was covered by 10 µg/cm2 -thick carbon layer to protect
the target from sputtering. Energy loss of the beam in
the target was estimated to be 5.4 MeV using a stopping power table. Beam energy at the half-depth oftargets was estimated to be 345.9 MeV. Sixteen targets were mounted on a rotating wheel 30 cm in diameter. The wheel was rotated at 2000 rpm during
irradiation. The reaction products were separated inﬂight from the beam by a gas-ﬁlled recoil ion separator,
GARIS,1) and were guided into a detector box placedat the focal plane of GARIS. The separator was ﬁlledwith helium gas at a pressure of 86 Pa. The value of themagnetic rigidity of GARIS in the evaporation residue
measurement was set at 2.09 Tm. The total dose of70
Zn was 4.4 × 1018 . All the other experimental conditions were almost identical to the ones adopted in theexperiment for the 209 Bi(64 Ni, n)272 111 reaction.2)
We observed two events of implantation of evaporation residues (ER) in a position-sensitive semiconductor detector (PSD) followed by four sequential αdecays terminated by spontaneous ﬁssion (SF) decays.
The probabilities of accidental coincidences between
the implantation and individual decays are estimatedby the same method as that described in Ref. 4. The
∗1
∗2
∗3
∗4
∗5
∗6
∗7

Saitama University
Niigata University
Center for Nuclear Science, University of TokyoJapan Atomic Energy Research Institute
University of Tsukuba
Institute of Modern Physics, China
Institute of High Energy Physics, China

maximum value is evaluated to be 3.0 × 10−4 for α4decay in the second chain. Decay energies, time intervals, and positions of the observed decay chains, aswell as the energy and position of ER, are summarizedin Table 1.
Decay energies of α1 in the present work, 11.09 ±0.07 MeV and 11.32 ± 0.04 MeV, diﬀer from the values
obtained at GSI, 11.45 MeV and 11.17 MeV, by about
0.10 MeV. Decay energies of α2 and α3 in the present
work agree well with the values obtained at GSI. Decayenergies of α4 in the present work were 8.71±0.04 MeV
and 8.70 ± 0.04 MeV, while the values obtained at GSI
were only partially measured in both chains.
Based on the comparison between the decay times
and the energies of the decay chain members observedin the present work and those observed in the work
done by the GSI group, the present result has provided a conﬁrmation of the discovery of 277 112 and its
daughter nucleus 273 Ds. The production cross sectionof isotope 277 112 by the 208 Pb(70 Zn, n) reaction was
deduced to be 0.44+0.59−0.29 pb using the transmission efﬁciency of 0.8 for GARIS.1)
Table 1. Summary of the observed events. ±: energy resolution in FWHM. ∆T : time diﬀerence between events.
Position: measured from the bottom of the detector.

ER

α1

α2

α3

α4

SF or α5chain 1E (MeV)∆T
Position
34.42
23.3 mm11.09 ± 0.07
1.10 ms
23.6 mm
11.14 ± 0.04
0.52 ms
23.5 mm
9.17 ± 0.04
14.2 s23.3 mm8.71 ± 0.04
23.0 s23.5 mm
197.3
2.97 s23.4 mmchain 2E (MeV)∆T
Position
35.13
18.5 mm11.32 ± 0.04
1.22 ms
18.3 mm
11.15 ± 0.07
0.040 ms
20.2 mm
9.25 ± 0.07
0.270 s19.0 mm8.70 ± 0.04
79.9 s18.1 mm
156.3
8.30 s18.5 mm

Nuclide

277

112

273

Ds

269

265

261

Hs

Sg

Rf

References
1) K. Morita et al.: Eur. Phys. J. A 21, 257 (2004).
2) K. Morita et al.: J. Phys. Soc. Jpn. 73, 1738 (2004).
3) S. Hofmann et al.: Eur. Phys. J. A 14, 147 (2002).
4) K. Morita et al.: J. Phys. Soc. Jpn. 73, 2593 (2004).

69

RIKEN Accel. Prog. Rep. 38 (2005)

Experiment on synthesis of element 113 in reaction
209
Bi(70 Zn,n)278 113†
K. Morita, K. Morimoto, D. Kaji, T. Akiyama,∗1 S. Goto,∗2 H. Haba, E. Ideguchi,∗3 R. Kanungo, K. Katori,
H. Koura,∗4 H. Kudo,∗2 T. Ohnishi, A. Ozawa,∗5 T. Suda, K. Sueki,∗5 H. Xu,∗6 T. Yamaguchi,∗7 A. Yoneda,
A. Yoshida, and Y.-L. Zhao∗8
278

113, new element, production and decay, gas-filled recoil ion separator
Finding the new isotopes of very heavy elements, including new elements, and studying their decay properties are interesting subjects in both nuclear physics
and nuclear chemistry. Since 2002, we have investigated the production and decay of 271 Ds (Z = 110)
and 272 111 using 208 Pb(64 Ni, n) and 209 Bi(64 Ni, n)
reactions, respectively,1,2) at the RIKEN Linear Accelerator Facility (RILAC). Subsequently, we studied
the isotope of the 112th element using the 208 Pb(70 Zn,n)277 112 reaction. Our results clearly confirmed the
production of the isotopes reported by Hofmann andcoworkers,3–8) and provided new spectroscopic information on the isotopes and their daughter nuclei. As
an extension of our previous work, we performed experiments aimed at synthesizing an isotope of larger
atomic number, Z = 113, using the 209 Bi + 70 Zn reaction.
The experiment was designed to produce the isotope 278 113 by the one-neutron evaporation channel
in the 209 Bi + 70 Zn complete fusion reaction. On thebasis of a systematic study of the most probable reaction energies for the one-neutron evaporation channel
in the 208 Pb(64 Ni, n)271 Ds, 209 Bi(64 Ni, n)272 111, and208
Pb(70 Zn, n)277 112 reactions, a reaction energy of
349.0 MeV at the half-depth of the targets was adopted
to maximize the relevant cross section for producing
278
113. The reaction products were separated in-flightfrom the beam using a gas-filled recoil ion separator,
GARIS, and were guided into a detector box placedat the focal plane of GARIS. The magnetic rigidity(Bρ) of GARIS for evaporation residue measurement
was set at 2.09 Tm. The experimental setup is almost
the same as the one used in experiments for 271 Ds and272
111 except for the targets. The detail of the experimantal setup is given in Morita et al.1)
As a result, the convincing candidate event of theisotope of the 113th element, 278 113, and its daughter
nuclei, 274 111 and 270 Mt, were observed, for the first
†
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8

70

Condensed from the article in J. Phys. Soc. Jpn. 73, 2593
(2004)
Saitama University
Department of Chemistry, Niigata University
Center for Nuclear Study, University of TokyoJapan Atomic Energy Research Institute
University of Tsukuba
Institute of Modern Physics, China
Department of Physics, Saitama University
Institute of High Energy Physics, China

time, in the 209 Bi + 70 Zn reaction at a beam energy of
349.0 MeV with a total dose of 1.7×1019 . The alpha decay energies and decay times of the candidates, 278 113,
274
111, and 270 Mt, were (11.68 ± 0.04 MeV, 0.344 ms),
(11.15 ± 0.07 MeV, 9.26 ms), and (10.03 ± 0.07 MeV,
7.16 ms), respectively. The production cross section of−39cm2 ).
the isotope was deduced to be 55+150−45 fb (10The decay chain is shown in Fig. 1, together with decayenergies (Eα and/or ESF ) and decay times.

Fig. 1. Decay chain observed in irradiation of 209 Bi targets
by 70 Zn projectiles. Measured energies and decay times
are indicated in the figure.

References
1) K. Morita et al.: Eur. Phys. J. A 21, 257 (2004).
2) K. Morita et al.: J. Phys. Soc. Jpn. 73, 1738 (2004).
3) S. Hofmann: Rep. Prog. Phys. 61, 639 (1998).
4) S. Hofmann et al.: Z. Phys. A 350, 281 (1995).
5) S. Hofmann et al.: Z. Phys. A 354, 229 (1996).
6) S. Hofmann and G. Münzenberg: Rev. Mod. Phys. 72,
733 (2000).
7) S. Hofmann et al.: Eur. Phys. J. A 14, 147 (2002).
8) S. Hofmann: J. Nucl. Radiochem. Sci. 4, R1 (2003).

RIKEN Accel. Prog. Rep. 38 (2005)

Electron scattering from unstable nuclei by
a novel SCRIT method (II)T. Suda, T. Emoto, S. Ito, T. Koseki, K. Kurita,∗ H. Morikawa,∗ M. Nakamura, T. Ohnishi, H. Takeda,
M. Wakasugi, and Y. Yano[electron scattering, RI, SCRIT]
Electron scattering is one of the most precise probes
for studying the internal structure of atomic nuclei,
and will surely play an essential role in the structurestudies of radioactive isotopes (RI) when an electronRI (eRI) scattering experiment becomes possible.
We propose a novel scheme for the eRI scatteringexperiment, SCRIT (Self-Conﬁning RI Target). This
novel method provides a localized RI target on theelectron beam in an electron storage ring. According
to numerical simulations, a suﬃciently high luminosity
for elastic electron scattering, 1027 /cm2 /s, is expected
for 107 /s ion injection with a 500-mA electron beam
current.1)
To study the feasibility of this SCRIT scheme, aprototype was designed and constructed in 2003. The
SCRIT prototype consists of an Cs ion source, an ion
transport line, SCRIT electrodes for ion trapping, anelectron detector2) and a luminosity monitor. In the
beginning of 2004, it was successfully installed in anexisting electron storage ring, KSR, of Kyoto University.
The following are the experiments we carried out
this year.
• SCRIT prototype in KSR: Immediately after the
installation and baking of the prototype, a seriesof test experiments were carried out with electron
beams. No serious eﬀects on the KSR performances, such as the beam lifetime and the maximum storaged current, were observed as a resultof the SCRIT prototype installation.
• Electron detector installation: An electron detector, consisting of a drift chamber, 12 plastic scintillators and 9 calorimeters, was installed. Prior to
the installation, all the calorimeters were energycalibrated using a monoenergetic (60 MeV) electron beam. The electron detector was conﬁrmed
to work well using a storaged electron beam of
80 mA. In particular, the drift chamber, placed
very close to the high-current electron beam, functioned normally using He+C2 H6 (50 : 50) gas. Figure 1 shows an example of one event during themeasurement at a storaged current of 50 mA. The
trajectory of an electron scattered at the SCRIT
electrodes is clearly reconstructed.
• Luminosity monitor installation: Bremsstrahlung
from trapped ions is to be measured for lumi∗

Rikkyo University

Fig. 1. Trajectory of a scattered electron measured using
the drift chamber.

nosity determination. A bremsstrahlung detector consisting of seven BaF2 crystals was placeddownstream of a straight section of KSR, where
the SCRIT prototype was installed. Prior to theinstallation, all BaF2 crystals were also energycalibrated. The background attributed to theshort beam lifetime of 1000 seconds was found to
be quite high, ∼ a few KHz, compared with the
expected bremsstrahlung rate of the trapped ions,∼500 Hz. Background reduction is essential for luminosity determination. The modiﬁcation of thebeam transport line, i.e., the installation of newbeam pipes and a severer collimation system, areunderway.
• Conﬁrmation of ion trapping: Although no direct
evidence of Cs ion trapping was observed in theluminosity monitor, the trapping of Cs ions in
SCRIT was conﬁrmed by the detection of ions
extracted from the trapping potential. It wasdemonstrated that SCRIT can trap an order of
107 ions for 10 seconds. It is suggested on the basis of our numerical simulation that the luminosityof an order of 1025 /cm2 /s is achieved.
The next step that should be carried out is the accurate determination of luminosity. In addition to thebremsstrahlung monitor, new monitors, which measurecharacteristic X-rays from the trapped Cs ions andMöller electrons from the collision between an electron beam and electrons in Cs ions, are planned to beinstalled.
References
1) M. Wakasugi, T. Suda, and Y. Yano: Nucl. Instrum.
Methods Phys. Res. A 532, 216 (2004).
2) T. Suda et al.: RIKEN Accel. Prog. Rep. 37, 81 (2004).

71

RIKEN Accel. Prog. Rep. 38 (2005)

Production of low-energy RI beam 46 Ar for secondary fusion reaction
E. Ideguchi,∗1 M. Niikura,∗1 C. Ishida,∗2 T. Fukuchi,∗1 H. Baba,∗1 N. Hokoiwa,∗3 H. Iwasaki,∗4
T. Komatsubara,∗5 T. Koike,∗6 T. Kubo, M. Kurokawa, S. Michimasa, K. Miyakawa,∗5
K. Morimoto, T. Ohnishi, S. Ota,∗7 A. Ozawa,∗5 S. Shimoura,∗1 T. Suda, M. Tamaki,∗1
I. Tanihata,∗8 Y. Wakabayashi,∗3 and K. Yoshida
NUCLEAR REACTION, 9 Be(46 Ar, xn)55−x Ti, Unstable nuclei, Fusion reaction
In-beam gamma-ray spectroscopy by fusion reactions has been one of the most eﬃcient methods for the
study of nuclear structure at a high spin since a large
angular momentum can be brought in to the reaction.
However, nuclei produced by fusion reaction using stable isotopes are limited in many cases to the protonrich side relative to the β-stability line. To study highspin states of neutron-rich nuclei by heavy-ion-induced
fusion reaction, it is necessary to use neutron-rich secondary beams. In the study of 50 Ti, a secondary fusion reaction, 46 Ar+9 Be, can be used to investigate
high-spin states where deformed collective states dueto the presence of deformed shell gaps1) in Z = 22 andN = 28 may approach the yrast state.
To actualize the method, a low-energy neutron-richsecondary beam has been developed. An 46 Ar beam
was produced at the RIPS Facility2) in RIKEN byfragmentation reaction. A primary 48 Ca beam withan energy of 63 MeV/nucleon was provided by the
RIKEN Ring Cyclotron with a maximum intensityof 100 pnA, and it was impinged on a 9 Be targetof 1.0 mm thick. An aluminum wedge with a mean
thickness of 221 mg/cm2 placed at the momentumdispersive focal plane (F1) was used to achieve a clear
isotope separation and to lower the energy of the fragment to 30 MeV/nucleon. By operating RIPS at the
maximum values of momentum acceptance and solid
angle, a typical intensity of 7.3 × 105 counts per second was obtained at the achromatic focal plane (F2).
Particle identiﬁcation of the secondary beam was performed by the time-of-ﬂight (TOF)-∆E method. The
purity of the 46 Ar beam was found to be 90% by thismethod.
46
Ar beam energy was further lowered using an
aluminum rotatable degrader of 0.5 mm thick at F2.
It was adjusted to 4.1 ± 0.9 MeV/nucleon, which
was estimated by the statistical model calculation(CASCADE)3) for an optimum production of 50 Ti via
secondary fusion reaction, 9 Be(46 Ar, 5n)50 Ti.
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8

72

Center for Nuclear Study, University of Tokyo
Department of Physics, Royal Institute of Technology,
SwedenDepartment of Physics, Kyushu University
Department of Physics, University of Tokyo
Institute of Physics, University of Tsukuba
Department of Physics and Astronomy, State University of
New York at Stony Brook, USA
Department of Physics, Kyoto University
Argonne National Laboratory, USA

The 46 Ar beam was transported to the ﬁnal focal
plane (F3) and irradiated on the secondary 9 Be targetof 10 µm thickness to induce the secondary fusion reaction. The intensity of the 46 Ar beam at F3 was about
3.2 × 105 counts per second.
Gamma rays emitted in the fusion reaction were
measured using a CNS segmented-Ge array, GRAPE.4)
Doppler correction was carried out on the basis of theposition, incident angle and energy of the beam obtained using beam proﬁle information deduced fromtwo PPAC counters5) placed upstream of the target
as well as TOF between the plastic signal at F2 andPPACs. Figure 1 shows the gamma-ray energy spectrum after Doppler correction. Gamma rays due to49,50,51
Ti6–8) are clearly observed.
Data analysis of the secondary fusion experiment isstill in progress.

Fig. 1. Doppler-corrected gamma-ray spectrum observedin 46 Ar + 9 Be fusion reaction.

References
1) E. Ideguchi et al.: Phys. Rev. Lett. 87, 222501 (2001).
2) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
461, 309 (1992).
3) F. Pühlhofer: Nucl. Phys. A 280, 267 (1977).
4) S. Shimoura et al.: CNS Annu. Rep. 2003, 87 (2004).
5) H. Kumagai et al.: Nucl. Instrum. Methods Phys. Res.
A 470, 562 (2001).
6) M. Behar et al.: Nucl. Phys. A 366, 61 (1981).
7) J. Styczen et al.: Nucl. Phys. A 327, 295 (1979).
8) S. E. Arnell et al.: Phys. Scr. 6, 222 (1972).

RIKEN Accel. Prog. Rep. 38 (2005)

Production of 39 Ar at the CRIB facility
Zs. Fülöp,∗1 H. Yamaguchi,∗2 Z. Elekes,∗1 S. Kubono,∗2 G. Amadio,∗2 H. Fujikawa,∗2 J. J. He,∗2 S. Michimasa,
J. Niikura,∗2 S. Nishimura, A. Saito,∗2 T. Teranishi,∗3 Y. Wakabayashi,∗3 and Y. Yanagisawa[NUCLEAR STRUCTURE, Half-life, Unstable nuclei]
The half-life is one of the basic properties of nuclei; consequently, it is well known for the majorityof isotopes. However, there are many questions not
only for isotopes far from the valley of stability, butalso for isotopes having half-lives of around a hundredyears or more, in which the determination of the decay
curve is getting diﬃcult and the measurement shouldbe very long. Alternative methods such as accelerator mass spectrometry (AMS) and half-life determinations based on geochemical considerations improve
the situation, but also have limitations. Recently, we
have developed a novel, fast and absolute implantation
method, by which the isotope in question is produced
as a radioactive beam, and implanted into a stopper,
and its speciﬁc activity is measured after the irradiation. The advantage of the implantation method
is that it allows absolute half-life determination withminimum systematic error and maximum versatility.
It is also important that the measurement gives reasonable error without years of data gathering. The ﬁrst
measurement with this technique aimed at the half-lifeof 44 Ti and the results1,2) conﬁrmed the recent data.
39
Ar is a 100% beta-decaying isotope with a half-lifeof 269 years. It can be produced by the 39 K(n,p)39 Ar
reaction underground3) and by cosmic-ray-induced
spallation reactions.4) The determination of the 39 Ar
concentration in rocks and groundwater gives valuable
data for geochemical studies. By comparing the concentration of 37 Ar (T1/2 = 35 d) with that of 39 Ar in
meteorites, the cosmic ray distribution in the solar system can be estimated.4) As shown in Table 1, apartfrom an early study5) with large errors, there is only
one measurement on the half-life of 39 Ar. Stoenner
et al.6) determined the half-life by mass spectrometry and activity determination and gave a result of
269 ± 3 y, upgrading their preliminary value of 325 y.7)

Table 1. Half-life measurements and compilations for39
Ar.
half-life
265 y
325 y
269 y
269 y
268 y
∗1
∗2
∗3

error
30 y
?
3y
3y
8y

methodmass spectr. + activity
relative to 37 Ar
relative to 37 Ar
compilation
re-evaluation of 6)

reference
5
7
6
8
9

This value is widely accepted and cited in compilations.8) It should be noted, however, that according
to Holden9) the error in the original data is underestimated by a factor of three and having reanalyzed theerrors, 268 ± 8 y was proposed. The half-life of 39 Ar
is too long to obtain its decay curve. For example, inthe case of 32 Si (T1/2 = 170 y), a measurement of four
years was necessary to give a result. Since argon is anoble gas, the AMS technique is also diﬃcult to apply, because a negative ion source is needed.10,11) The
implantation method, however, is suitable for the 39 Ar
half-life measurement, because it is not necessary to
determine the decay curve, but only to detect the activity of the implanted isotopes. As a ﬁrst step towards
the determination of 39 Ar half-life, the production of
39
Ar was tested at the CNS low-energy in-ﬂight type
RI beam separator, CRIB. The 39 Ar particles were
produced by (3 He,4 He) reaction in inverse kinematics
using a 4.5 MeV/nucleon 40 Ar with a 3 He gas target.
The 39 Ar products were separated at charge states of
15+ and 16+ by the CRIB separator, and further separation was provided by a Wien ﬁlter. Two PPACs
and a silicon detector served as detectors for particle
identiﬁcation and position determination. The 39 Ar
particles were completely separated from 40 Ar at abeam rate of 104 cps, and the 39 Ar content was around500 cps. In summary, the achieved intensity allows the
preparation of 39 Ar samples by implantation to investigate its half-life.
References
1) Zs. Fülöp et al.: in Proc. Nuclei in the Cosmos V,
edited by N. Prantzos and S. Harissopulos (Editions
Frontieres, Paris, 1998), p.281.
2) T. Hashimoto et al.: Nucl. Phys. A 686, 591 (2001).
3) T. Florkiwski: J. Phys. G 17, S513 (1991).
4) R. C. Reedy et al.: Science 219, 127 (1983).
5) H. Zeldes et al.: Phys. Rev. 86, 811 (1952).
6) R. W. Stoenner et al.: Science 148, 1328 (1965).
7) R. W. Stoenner et al.: J. Geophys. Res. 65, 3025
(1960).
8) P. M. Endt: Nucl. Phys. A 521, 1 (1990).
9) N. E. Holden: Pure Appl. Chem. 62, 941 (1990).
10) W. Kutschera: Annu. Rev. Nucl. Part. Sci. 40, 411(1990).
11) I. Ahmad et al.: ANL Ann. Rep. 2001, ANL-02/15,
79 (2002).

ATOMKI, Hungary
Center for Nuclear Study, University of Tokyo
Kyushu University

73

RIKEN Accel. Prog. Rep. 38 (2005)

Magnetic-ﬁeld eﬀect in muon-catalyzed dt fusion in liquidand solid D/T mixtures
K. Ishida, T. Matsuzaki, M. Iwasaki, Y. Matsuda, K. Nagamine,∗1 N. Kawamura,∗1
H. Imao,∗2 M. Kato,∗3 H. Sugai,∗3 and G. H. Eaton∗4[Muon-catalyzed fusion]
In muon-catalyzed fusion (µCF), a high fusion yield
can be achieved with a high λc (cycling rate of µCFprocess) and low W (muon loss per cycle). Here, W isdominated by muon-to-alpha sticking with the muon
being captured by the Coulomb ﬁeld of an α particle produced by fusion, which occurs with a small but
non-negligible probability of less than 1% per fusion.
µCF has been studied under a variety of D/T target
conditions to understand the basic processes and to increase the fusion yield. Although the eﬀect of magnetic
ﬁeld in µCF is one of the important practical parameters, there have been only a few theoretical studies
on, for example, the convoy muon eﬀect1) and ﬁeldinduced transition in αµ,2) and there have been no experimental studies. Thus, we started measurements ofthe magnetic-ﬁeld dependence of µCF at the RIKENRAL Muon Facility.
A preliminary study with a liquid D/T target wasreported in the last progress report.3) The experiment
was carried out under four magnetic-ﬁeld settings (0,1.2, 2.4 and 3.3 T) for liquid D/T with a tritium concentration of 30%. Fusion neutrons and various muonic
X-rays were detected. This time, we changed the target condition to solid at 16 K and 8 K to study how theﬁeld dependence is aﬀected by the target density andtemperature.
Figure 1 shows the observed magnetic ﬁeld dependence of the cycling rate, the muon loss probability,
and the yield of αµ Kα X-rays per fusion. Our new
data on solid D/T generally show the same tendencies
as those of liquid D/T. Within the statistical error of±5%, no signiﬁcant dependence on the magnetic ﬁeldof either the cycling rate or the muon loss probability
was observed, while the αµ Kα X-ray yield increased
with the ﬁeld by as much as 30%. The result is opposite
to the prediction based on the convoy eﬀect,1) which
predicts decreasing muon-to-alpha sticking and X-ray
yield as the ﬁeld is increased. However, the stimulatedtransition2) enhances 2s-2p mixing in αµ and increases
the Kα emission by competing with further excitation
or stripping from the 2s state. Thus it is consistent
with, or at least does not contradict with, our results.
∗1

∗2
∗3
∗4

74

Muon Science Laboratory, Institute of Materials Structure
Science, High Energy Accelerator Research Organization(KEK)
Department of Physics, University of Tokyo
Tokai Research Establishment, Japan Atomic Energy Research Institute (JAERI)
Rutherford Appleton Laboratory, UK

Fig. 1. Preliminary result on field dependence of µCF cycling rate (λc ), muon loss per cycle (W ), and the yieldof αµ Kα X-rays per fusion for three target conditions,
20 K liquid, 16 K solid and 8 K solid.

In this process, however, its eﬀect on the muon-sticking
loss is not zero but small because the initial sticking
to the αµ 2s state is calculated to be less than 20% of
the total initial sticking and the loss is dominated byinitial muon sticking to the αµ 1s state.
In summary, our result implies a ﬁeld eﬀect thatenhances the sticking Kα X-ray emission but does
not simply increase the overall sticking. The ﬁeldstimulated transition is one of the candidates of thecause of such an eﬀect.
References
1) B. Müller, H. E. Rafelski, and J. Rafelski: Phys. Rev.
A 40, 2839 (1989).
2) V. S. Melezhik and P. Schmelcher: Phys. Rev. A 59,
4264 (1999).
3) K. Ishida et al.: RIKEN Accel. Prog. Rep. 37, 91(2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Muon catalyzed t-t fusion and muon transfer experiments
using liquid and solid T2 targets
T. Matsuzaki, K. Nagamine,∗1 K. Ishida, N. Kawamura,∗1 H. Imao,∗1,∗2 Y. Matsuda, M. Iwasaki, M. Kato,∗3
H. Sugai,∗3 M. Tanase,∗3 S. N. Nakamura,∗4 K. Kudo,∗5 A. Uritani,∗5 H. Harano,∗5 and G. H. Eaton∗6Muon catalyzed t-t fusion, muon transfer reaction, 3 He acccumulation in solid T2
Muon catalyzed t-t fusions (t-t µCF) take placespontaneously when negative muons stop in a tritium(T2 ) target. The negative muons form tµ atoms bybinding to triton nuclei (t), and the tµ atoms then collide with T2 molecules to form ttµ molecules. The t-t
fusions occur in the framework of ttµ molecules, andinduce a three-particle decay consisting of an α-particle
and two neutrons. After the t-t µCF process, muons
are liberated and participate in the next t-t µCF reaction.
t + t + µ → (ttµ) → α + n + n + µ + Q(11.33 MeV)(1)
For some probability, the muon is captured by the αparticle and muonic X-rays are emitted, thus terminating the t-t µCF cycle. This phenomenon is termedmuon sticking.
t + t + µ → (ttµ) → (µα) + n + n + Q

and three calibrated NE213 liquid scintillators (2 inchφ× 2 inch) were used. Typical delayed photon spectra
obtained for solid and liquid T2 targets are respectively shown in Fig. 1 and Fig. 2. We clearly observed
Kα (8.21 keV) and Kβ (9.6 keV) muonic X-rays originated from µα atoms formed in the muon sticking
processes. In addition, we can see characteristic radiative photons at 6.76 keV in Fig. 1, originating fromthe radiative decay of excited intermediate t3 Heµ mesomolecules in muon transfer process from tµ atoms
to accumulated 3 He nuclei in solid T2 targets. In contrast, the 6.76 keV photon was not observed at all in
liquid target runs (Fig. 2), indicating that 3 He does notaccumulate at all in liquid T2 . By analyzing photon
and neutron data, we will clarify important parameters in t-t µCF and muon transfer processes, including
their temperature-dependent behavior. This analysis
is currently in progress.

(2)

The 6.76 keV radiative photons are generated in association with the muon transfer process from tµ atoms
to the accumulated 3 He nuclei through intermediate(t3 Heµ) mesomolecule formation,1) where 3 He is the
decay product of tritium. The muon transfer process
is described astµ + 3 He → (t3 Heµ)∗ → t + (3 Heµ) + γ(6.76 keV).
(3)

Fig. 1. A typical photon spectrum for solid T2 targets.

We conducted the experiment at the RIKEN-RAL
Muon Facility.2) A high-purity tritium gas (T: 99.4%,
H: 0.6%, D: < 100 ppm), produced by Ontario Power
Generation Inc. in Canada, was imported to RAL.
Tritium gas was purified in an in situ tritium gashanding system3) to remove any 3 He impurities originating from tritium β-decay. The tritium gas (inventory of 1479 Ci) was liquefied and solidified in atarget. For the photon and neutron detections, aSi(Li) X-ray detector (70 mm2 × 3.5 mm thickness)

Fig. 2. A typical photon spectrum for liquid T2 targets.

∗1

∗2
∗3
∗4
∗5

∗6

Meson Science Laboratory, Institute of Materials Structure
Science, High Energy Accelerator Research Organization(KEK)
Faculty of Science, University of Tokyo
Department of Radioisotopes, Japan Atomic Energy Research Institute (JAERI)
Department of Physics, Tohoku University
Quantum Radiation Division, Metrology Institute of Japan,
National Institute of Advanced Industrial Science and Technology (AIST)
ISIS, Rutherford Appleton Laboratory (RAL), UK

References
1) T. Matsuzaki, K. Nagamine, K. Ishida, and K.
Kawamura: Phys. Lett. B 527, 43 (2002).
2) T. Matsuzaki, K. Ishida, K. Nagamine, I. Watanabe,G. H. Eaton, and W. G. Williams: Nucl. Instrum. Methods Phys. Res. A 465, 365 (2001).
3) T. Matsuzaki, K. Nagamine, M. Tanase, M. Kato, andK. Kurosawa: Nucl. Instum. Methods Phys. Res. A 480,
812 (2002).

75

RIKEN Accel. Prog. Rep. 38 (2005)

Dimuon measurement in indium-indium collisions at the CERN/SPS
H. Ohnishi and J. M. Heuser[heavy-ion collisions, quark-gluon plasma, charm quark]
The use of high-energy heavy-ion collisions is known
to be one of the possible ways of creating nuclear matter with high energy density. Normal nuclear mattermay then undergo a phase transition to a new state ofmatter, the quark-gluon plasma (QGP). The observed
J/ψ suppression pattern in high-energy heavy-ion collisions at CERN’s Super Proton Synchrotron (SPS)
seems to provide the ﬁrst signal of color deconﬁnement through parton condensation. Simultaneously,
an enhancement of dimuons in the Intermediate Mass
Region (IMR, 1.5 < Mµµ < 2.5 GeV) is observed, withthe main contributions expected to be from decays ofcharm mesons and dimuons originating from Drell-Yan
processes. So far, however, there have been no indications that this color condensate subsequently leads toa medium in thermal equilibrium, e.g., the QGP.
One of the relevant issues that the NA60 experiment intends to address is the origin of the enhancement of IMR dimuons. Two hypotheses are proposed:
enhancement of charm meson production in heavy-ion
collisions, and thermal dimuon production from thecreated medium, which is direct evidence of QGP formation. To clarify this issue, we must be able to isolate
the considerable yield of dimuons coming from decaysof charm mesons. Due to the long life time of charmmesons, the origin of muons coming from charm meson
decays will be oﬀset from the primary vertex. Therefore, we need to perform secondary vertex measurements that provide approximately 50 µm resolution.
The NA60 experiment comprises four main detector components: the vertex spectrometer, hadron absorber, zero-degree calorimeter and muon spectrometer. The vertex spectrometer consists of a 16-plane
tracking telescope in a 2.5 T magnetic ﬁeld, built fromradiation tolerant silicon pixel detectors developed for
the ALICE experiment at the Large Hadron Collider.
A vertex telescope tracks the large number of charged
particles created from collisions of heavy-ion or proton
beams on nuclear targets. Only muons pass throughthe hadron absorber and are tracked by the muon spectrometer. In the oﬄine analysis, muons reconstructedin the muon spectrometer are matched in both spatial
and momentum coordinates with one of the charged
tracks measured using the vertex telescope. In thisway, complete muon tracks are identiﬁed from thetarget region to the muon spectrometer. This track
matching allows us to signiﬁcantly improve the dimuon
mass resolution since we can analyze the muon kinematics before the scattering in the hadron absorber.
During the NA60 run in 2003, beams of indium ionswere collided at 158 GeV/nucleon with indium targets.

76

The analysis of the data is in progress, and the mass
resolution at the φ mass is found to be 23 MeV. The
advantage of muon matching is that we can identify
the origin of the muon. The resolution of the oﬀset
of the tracks from the collision vertex is analyzed withdimuons from J/ψ decays and yields the design value of
50 µm for the vertex telescope.1) This is consistent withthe expected performance evaluated in Monte Carlosimulations.
To demonstrate the identiﬁcation of the charm decay contribution, dimuons are separated into two sub
samples. One is the prompt sample, where both muonsoriginate from the collision vertex. The other is the oﬀset sample, where the origin of both muons is locatedaway from the collision vertex. Figure 1 (a) shows the
dimuon mass distributions of the prompt and oﬀset
samples, and Fig. 1 (b) shows their ratio. Large reductions in the dimuon yields at the dimuon masses
dominated by the ω, φ and J/ψ peaks are clearly visible in the prompt sample. A clear excess is seen in theoﬀset dimuon sample in the mass window where thecharm decay contribution is dominat. Further analysis is under way to extract the production cross sectionof the charm quark.
From August to November 2004, we recorded datawith 400 GeV protons colliding with Be, Al, Cu, In,
Pb, W and U targets. We expect about 500 k dimuons
from J/ψ and almost the same amount of signal fromcharm mesons at IMR in the data. These will be goodreferences for the results from indium-indium collisions
and will help clarify the reason for the enhancementof IMR dimuons, that is, whether it is due to IMR
dimuons originating from QGP or to the enhancementof charm meson production in heavy-ion collisions.

Fig. 1. (a) Dimuon mass distributions of prompt and oﬀset
muon pairs. (b) Ratio of the mass distributions withand without track oﬀset requirement.

Reference
1) H. Ohnishi et al: To be published in J. Phys. G.

RIKEN Accel. Prog. Rep. 38 (2005)

Experimental signature of in-medium mass modification of ρ/ω/φmesons at normal nuclear density
R. Muto, H. En’yo, M. Naruki,∗ F. Sakuma,∗ T. Tabaru, and S. Yokkaichi, for the KEK-PS E325 Collaboration[QCD, chiral symmetry, normal nuclear density, mass modiﬁcation, vector meson]
KEK-PS E325 experiment measured the invariant
mass spectra of e+ e− pairs in 12 GeV p + A interactions at KEK Proton-Synchrotron. The aim of thisexperiment was to detect the in-medium mass modiﬁcation of vector mesons at a normal nuclear density,
which was theoretically expected as a precursor of chiral phase transition.
In our earlier publication, we reported the signatureof mass modiﬁcation of ρ/ω mesons.1) From the observed modiﬁcation, however, it was not easy to diﬀerentiate the eﬀects of ρ mesons from those of ω mesonson the invariant mass spectrum. In this report, we focus on the analysis of another vector meson, φ. Thereis no other resonance near the φ meson mass, thus
we are able to examine the possible mass modiﬁcation
more clearly.
The decrease in φ meson mass at a normal nuclear
density was expected to be about 20–40 MeV/c2 according to the calculation by Hatsuda and Lee.2) If
such a mass modiﬁcation occurs, the observed spectrum becomes the summation of two components, amass peak of normal in-vacuum decays and a low-masstail from in-medium decays. A large amount of thetail was expected for a large target nucleus, because
the decay probability inside the nucleus was high. Experimentally, we compared the mass spectra of carbon
and copper targets to examine the nuclear mass dependence of the modiﬁcation tails.
We reanalyzed all the data with an improved trackreconstruction technique. Through this process thestatistics of the φ meson were almost doubled. We also
performed event generation using cascade code JAM3)
and detailed detector simulation using Geant4.4) To
analyze the shape of the φ meson peaks, it is important to understand the detector response precisely. We
found that the invariant mass spectrum of Ks → π + π −was well reproduced by this simulation.
Using the mass shape of the φ meson obtained fromthis simulation, together with a quadratic curve for the
background shape, the mass region from 0.85 GeV/c2
to 1.2 GeV/c2 was analyzed. When we included all
the data points in the ﬁtting, the reduced χ2 ’s were1.33 (DOF = 49) for the carbon target and 2.18
(DOF = 49) for the copper target. The χ2 ’s were
improved to 1.30 (DOF = 40) and 1.61 (DOF = 40)
for the carbon and copper targets, respectively, by excluding the region from 0.95 GeV/c2 to 1.01 GeV/c2 ,where the modiﬁcation tails could appear. The ﬁtting∗

Department of Physics, Kyoto University

results excluding the excess region are shown in Fig. 1.
We conclude that the φ meson mass shape of thecopper data is not reproducible with the expected detector resolution at a 99% conﬁdence level, although
the carbon data is reproducible. A possible reason forthis is the φ meson mass modiﬁcation in nuclei.
In these analyses, we used approximately 220,000
cpu·hours of the excellent cpu power of RIKEN
CC-J and RIKEN Super Combined Cluster System(RSCC).5) We are grateful for the support from thesecomputing facilities.

Fig. 1. Invariant mass spectra of the e+ e− pair for a) the
carbon target and b) the copper targets. Gray lines
show the best fitting result of the simulated mass shape,and dotted lines, the quadratic background. Fitting
was performed excluding the region from 0.95 GeV/c2
to 1.01 GeV/c2 (shown as regions without error bars).

References
1) R. Muto et al.: RIKEN Accel. Prog. Rep. 37, 85 (2004).
2) T. Hatsuda and S. H. Lee: Phys. Rev. C 46, R34 (1992).
3) Y. Nara et al.: Phys. Rev. C 61, 024901 (1999).
4) S. Agostinelli et al.: Nucl. Instrum. Methods 506, 250(2003).
5) S. Yokkaichi et al.: RIKEN Accel. Prog. Rep. 38, 247(2005).

77

RIKEN Accel. Prog. Rep. 38 (2005)

Time-delay-matrix analysis of resonance scattering: General theory
and Coulomb-three-body systems with diverging backgroundI. Shimamura and A. Igarashi∗
Resonance analysis of multichannel atomic andmolecular scattering and photoionization calculations
has traditionally been based on the Breit-Wigner(BW) formula for the eigenphase sum δ(E)1)
tan[δ(E) − δ 0 (E)] = (Γ/2)/(Er − E),(1)where δ 0 is the background eigenphase sum. This formula is ﬁtted to calculated δ(E) to extract resonanceparameters, i.e., positions Er and widths Γ.
Later, the derivative dδ(E)/dE with respect to energy E turned out to be more useful than δ(E) itself
for resonance analysis. For one thing, resonances standout more clearly in dδ/dE than in δ. For another,dδ/dE is related to the lifetime h̄/Γ of the resonancestate, leading to transparent physical interpretation.
Smith’s lifetime or delay-time matrix Q(E) satisﬁes2)
Q(E) = ih̄SdS † /dE = −ih̄(dS/dE)S † = Q† (E) (2)in terms of the S matrix. If S takes a BW form

1/2 1/2iΓi Γjiφieiφj ,
Sij = eδij −(3)E − Er + iΓ/2where Γ ≡ i Γi , and where the background phases φiand φj and partial widths Γi and Γj are assumed to beconstants, the trace of Q has a Lorentzian proﬁle, i.e.,
Tr Q(E) = h̄Γ/[(E −Er )2 +(Γ/2)2 ],3) and the diagonal
elements are given by Qii = (Γi /Γ)Tr Q. If δ 0 in (1) isassumed to be constant, this Lorentzian form satisﬁes
Tr Q(E) = 2h̄ dδ(E)/dE.

Tr Q(E) =h̄ΓC1−+ C0 ,
2
2(E − Er ) + (Γ/2)
E − Eth(5)

which turns out to ﬁt very well even for huge background overcoming the Lorentzian term. The heightof this term is related to its width by Γ. If the heightneeds to be scaled by a constant in a ﬁtting to computed
Tr Q(E), it suggests errors in the computation.
As an example, Fig. 1 shows results for 3 P o positronscattering by positronium Ps just above the Ps(n = 3)
threshold.5) The eﬀect of an S-matrix pole is seen in
one of the eigenvalues qi (E) of Q(E), but δ(E) decreases monotonically and Tr Q(E) (average time delay) is negative due to the overcritical dipole potential.

(4)

This has the same form as the relation of the phaseshift with the time delay in single-channel scattering.
However, the BW formula (3) is too restrictive foranalysis of atomic/molecular resonances. It assumes
the background S matrix to be diagonal (i.e., inelastic scattering is forbidden, which is impractical) andindependent of E (which can be generalized for Edependent background).
We have proved (4)4) for any E-dependent S(E) orδ(E), i.e., for E-dependent background, for overlapping resonances, oﬀ any resonances, or for the case of
no resonances existing. The proof is very general, being based only on relation (2). It applies not only toatomic/molecular physics but also to nuclear physics
and any other ﬁeld of physics where S is deﬁned.
An interesting case is the nonrelativistic interaction of a charged particle A with a hydrogenlike atomBC(nl), where an asymptotic dipole term ∼µr −2 exists. If it is overcritically attractive, δ(E) diverges toward a threshold Eth of BC(nl), violating the Wigner∗

threshold law. Then a resonance just above Eth may
have a background δ 0 (E) with a strong negative slope,which washes away the eﬀect of an S-matrix pole andproduces “negative time delay” or “time advance.” Forsuch cases we have proposed a ﬁtting formula5)

Fig. 1. Positron-positronium 3 P o eigenphase sum δ(E) andthe trace (= 2h̄dδ/dE) (− − −) and eigenvalues qi (E)(——) of the Q matrix plotted vs. energy E.

References
1) A. U. Hazi: Phys. Rev. A 19, 920 (1979).
2) F. T. Smith: Phys. Rev. 118, 349 (1960).
3) L. Celenza and W. Tobocman: Phys. Rev. 174, 1115
(1968).
4) A. Igarashi and I. Shimamura: Phys. Rev. A 70, 012706(2004).
5) A. Igarashi and I. Shimamura: J. Phys. B: At., Mol.
Opt. Phys. 37, 4221 (2004).

Department of Applied Physics, Miyazaki University

79

RIKEN Accel. Prog. Rep. 38 (2005)

Apparent discrepancy between the complex-rotation andhyperspherical results now resolved: e+ + He+ scattering
A. Igarashi∗ and I. Shimamura
In Coulomb-three-body scattering, e.g., e− or e+scattering by H or He+ , the correlation between the
two light particles is crucial. Its standard treatment
used to be to include in the wave function the distancer12 between the light particles, as in the Hylleraas coordinates.1,2) Later, it has been superseded by the hyperspherical (HS) coupled-channel (CC) method,3–5)
which is far more powerful from both numerical accuracy and transparent physical interpretation. The HS
coordinates have been useful also for complete solutions of the long-standing problem of breakup in e− +H
scattering using the well-known exterior complex scaling, and the time-dependent Schrödinger equation.6)
The HS coordinates are ﬁve-dimensional hyperangles and a hyperradius ρ = (r12 +r22 )1/2 , r1 and r2 being
distances of the two light particles from the nucleus.
The ρ plays a role similar to the ion-atom distance inthe molecular-base theory of ion-atom collisions; scattering may be described using adiabatic HS potentials
Vii (ρ) and the nonadiabatic couplings Vij (ρ).
The system He2+ e− e+ is interesting because of afew distinct kinds of asymptotic channels; channels
e+ + He+ with a repulsive Coulomb potential ∝ r −1 ,and channels He2+ + Ps(nl) with attractive polarization potential ∝ r −4 if the positronium Ps is in 1s state,
or with either attractive or repulsive dipole potential∝ r −2 if n ≥ 2. Many avoided crossings occur between
attractive and repulsive HS potentials with diﬀerent n,producing rich physics clearly describable using adiabatic HS states.5) Overcritical dipole potentials leadto inﬁnite series of Feshbach resonances and a strange
threshold law violating the Wigner law,7) the cross section oscillating inﬁnite times close to the threshold.
By solving 42 HSCC equations for S-wave e+ + He+
scattering we calculated positions Er and widths Γof 9 narrow resonances from the rapidly rising eigenphase sum δ(E),5) 3 of which had been detected by thebound-state-type complex-coordinate rotation method(CRM).8) We also obtained 10 narrow P -wave resonances from 73 HSCC equations,5) of which 4 had been
detected by the CRM.8) The agreement between the
HSCC and CRM values is excellent when both exist.
CRM also found two S-matrix poles with large Γin each partial wave L ≤ 6.8) In both HSCC4) andconventional CC calculations,9) δ(E) increased only
weakly in the energy region of the lower “broad resonance” and decreased monotonically (meaning negative time delay) in the higher region. This disaccord between the bound-state-type and scattering approaches, however, has been resolved by our time-delay∗

80

Department of Applied Physics, Miyazaki University

matrix analysis,5) described in Ref. 7.
S-matrix poles at E = Er − iΓ/2 can produce resonance scattering, provided that Γ is small enoughfor the poles to aﬀect the actual process occurring at
real E. A counterexample is the case of shorter lifetime h̄/Γ than the nonresonant collision time. Anothercounterexample occurs for a strong background thatmakes δ(E) hardly increase in the region of width ∼Γnear Er ; see Fig. 1 in the preceding report.7) A very
similar behavior of δ(E) is found in the higher “broadresonance” region in e+ + He+ scattering.5) This was
responsible for the seemingly inconsistent HSCC andCRM results; ﬁtting of HSCC time-delay matrix resulted in S-matrix poles consistent with CRM.
The strong background overcoming the S-matrixpole eﬀect is due to the long-range dipole potential
Vd (r), and is lost unless the scattering equations are
solved up to very large r. We treated Vd (r) analytically, and hence up to r → ∞ in eﬀect. In recent timedependent CC calculations10) a boundary was set at afairly small r (= a), only within which the time delay
was calculated, naturally resulting in a positive value.
Also, the peak height of the delay time contradicted
their widths,7) which may be due to the ﬂux loss at
the artiﬁcial absorption potential set at r = a.
References
1) C. Schwartz: Phys. Rev. 124, 1468 (1961).
2) I. Shimamura: J. Phys. Soc. Jpn. 30, 1702 (1971); J.
Phys. Soc. Jpn. 31, 217 (1971); J. Phys. Soc. Jpn. 31,
852 (1971); V. I. Korobov and I. Shimamura: Phys.
Rev. A 56, 4587 (1997).
3) J.-Z. Tang and I. Shimamura: Phys. Rev. A 50, 1321
(1994); Phys. Rev. A 51, R1738 (1995); Phys. Rev. A
52, R3413 (1995).
4) A. Igarashi and I. Shimamura: Phys. Rev. A 56, 4733
(1997); A. Igarashi, I. Shimamura, and N. Toshima:
Phys. Rev. A 58, 1166 (1998); New J. Phys. 2, 17(2000); A. Igarashi, M. Kimura, and I. Shimamura:Phys. Rev. Lett. 89, 123201 (2002).
5) A. Igarashi and I. Shimamura: Phys. Rev. A 70,
012706 (2004); J. Phys. B 37, 4221 (2004).
6) T. Rescigno et al.: Science 286, 2474 (1999); C. W.
McCurdy et al.: Phys. Rev. A 65, 042714 (2002); J.
Colgan et al.: Phys. Rev. A 65, 042721 (2002).
7) I. Shimamura and A. Igarashi: RIKEN Accel. Prog.
Rep. 38, 79 (2005).
8) Y. K. Ho: Phys. Rev. A 53, 3165 (1996); Y. K. Hoand Z.-C. Yan: Phys. Rev. A 66, 62705 (2002).
9) B. H. Bransden et al.: J. Phys. B 34, 2267 (2001).
10) N. Yamanaka et al.: Phys. Rev. A 70, 062701 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Electron capture in H+ +NH2 collisions between 0.5 and 1.5 keV
H. Suno,∗1 M. Kimura,∗2 R. J. Buenker,∗3 and L. Pichl∗4Electron capture in collisions of ions with atoms in
keV-energy regions is one of the most important processes in experimental and theoretical atomic physics
as well as in applications to astrophysics and fusion
research. Relatively comprehensive studies have been
carried out for various atomic targets and charged projectiles in a wide range of collision energies (meV tokeV), but those for molecular targets are still rare,both experimentally and theoretically.
This report concerns a theoretical investigation of
the electron capture process in the collision of H+
ions with NH2 molecules in the region below 1.5 keV.
These hydronitrogen molecules, NH2 , exist in various
atmospheric and astrophysical environments. They
also play a key role in various molecular reactions involving nitrogen atoms in the universe. Since an exact quantum-mechanical treatment of the NH+
3 systemwould be diﬃcult, we consider four diﬀerent trajectories for collision dynamics: (i) the proton approaches
the N atom along the bisector of the H-N-H bond angle, passing the midpoint of the H-H line; (ii) it travels
along the same line as in (i), but in the opposite direction; (iii) the proton approaches the N atom on the
H-N-H plane and perpendicularly to the bisector of the
H-N-H bond angle; (iv) the proton approaches the N
atom perpendicularly to the H-N-H plane.
Adiabatic potential-energy curves are calculatedby the multireference single- and double-excitation
conﬁguration-interaction (MRD-CI) method,1,2) with
conﬁguration selection and energy extrapolation employing the Table-CI algorithm.3) Ab initio calculations are performed for each of the four conﬁgurations mentioned above. Scattering dynamics is studied on the basis of the fully quantum formulation of amolecular-orbital expansion method. The total scattering wave function is described in an adiabatic representation as an expansion in products of electronic
and nuclear wave functions and the electron translation
factor. The substitution of the total scattering wave
function into the stationary Schrödinger equation andtransformation to the diabatic representation4) yield
the coupled equation1dR I − V (R) + EI X d (R) = 0,(1)2µwhere µ is the reduced mass of the system, I the identity matrix, V d the diabatic potential-energy matrix,
and X d (R) the nuclear wave function in the diabatic
∗1
∗2
∗3
∗4

National Institute for Fusion Science
Graduate School of Sciences, Kyushu University
Theoretische Chemie, Bergische Universität-Gesamthoscschule Wuppertal, Germany
University of Aizu

representation. The coupled Eq. (1) is solved numerically to obtain the scattering S l matrix for each partial
wave l.5) The diﬀerential cross section is then given by
2


dσ(θ)
1 

l
= 2  (2l + 1){δif − Sif }Pl (cos θ) , (2)

dΩ
4k 
l

where k = (2µE)1/2 is the momentum of the projectile and θ the scattering angle in the center of mass
coordinates.
Diﬀerential cross sections for electron capture areshown in Fig. 1 for all four molecular conﬁgurations(i)–(iv), for scattering angles of 0◦ -180◦ at 1.5 keV. For
all cases, the diﬀerential cross sections oscillate rapidly
when θ ≤ 5◦ , while they are all relatively smooth when5◦ ≤ θ ≤ 25◦ . We noted that the magnitude of thediﬀerential cross section for case (i) is nearly the sameas that for case (ii) in the region θ ≤ 60◦ . For all cases,
oscillatory structures are present when θ ≥ 60◦ .
In conclusion, the dependences on the molecular orientation — the steric eﬀects — are conspicuous in
H+ +NH2 collisions.

Fig. 1. Diﬀerential cross sections for electron capture forthe four molecular conﬁgurations (described in the text)
at 1.5 keV.

References
1) R. J. Buenker and S. D. Peyrimhoﬀ: Theor. Chim. Acta35, 33 (1974).
2) R. J. Buenker: Int. J. Quantum Chem. 29, 435 (1986).
3) R. J. Buenker: Proc. Workshop on Quantum Chemistry
and Molecular Physics, Wollongong, Australia, editedby P. Burton (University Press, Wollongong, 1980).
4) M. Kimura and N. F. Lane: Adv. At. Mol. Opt. Phys.
26, 79 (1989).
5) B. H. Bransden: Atomic Collision Theory (Benjamin,
New York, 1983).

81

RIKEN Accel. Prog. Rep. 38 (2005)

Charge transfer processes by proton in collisions withC2 H4 molecule below 10-keV
R. Suzuki,∗1 S. N. Rai,∗2 H.-P. Liebermann,∗3 R. J. Buenker,∗3 L. Pichl,∗4 and M. Kimura∗5
Charge transfer and direct elastic scattering in collisions of proton with C2 H4 molecules are studied byusing a molecular representation within a semiclassical as well as fully quantum-mechanical approaches1)
below 10 keV. The coordinate system for the projectile
and the target molecule of the [H + C2 H4 ]+ collisionsystem is shown in Fig. 1. The C=C bond is placedalong the X-axis with its midpoint at the origin of
coordinate system, and C-H bonds all lie in the XY plane. Calculations are carried out at three diﬀerent
molecular conﬁgurations (X, Y, Z-direction conﬁguration), in which proton approaches (X) parallel, and(Y ) perpendicular to the C=C axis in the molecularplane, and (Z) perpendicular to this plane. The adiabatic potentials2) of the system are shown in Fig. 2.

Diﬀerential cross sections from the initial state B
to the charge transferred state C for (X), (Y ), (Z)at 1.5 keV are shown in Fig. 3. We ﬁnd that chargetransfer in the (Z) takes place preferentially over thatin the (X) and (Y ) at scattering angles above 15◦ ,while the results for (X) and (Y ) are comparable inmagnitude below 10◦ , although (Y ) dominates slightly
at still smaller angles. Total charge transfer cross sections are shown in Fig. 4. The results for the (Z) and(Y ) diﬀer by a factor of four above 500 eV, while thosefor (X) lie between these values. Below 500 eV, the results for (X) and (Z) are similar in magnitude, whilethat for the (Y ) sharply decreases.

Fig. 1. Schematic diagram indicating the molecular axis
orientation for the [H + C2 H4 ]+ collision system.
Fig. 3. Diﬀerential cross sections from the initial state B
to the charge transferred state C.

Fig. 2. The adiabatic potentials of the [H + C2 H4 ]+ system for the Z-direction. The proton moves along the
Z-axis toward the midpoint of the C=C bond.
∗1
∗2
∗3
∗4
∗5

82

Computer Center, Hitotsubashi University
Computer Center, Bijni Complex, North-Eastern Hill University, India
Fachbereich C-Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, Germany
Foundation of Computer Science Laboratory, University of
Aizu
Graduate School of Sciences, Kyushu University

Fig. 4. Total cross sections from the initial state B to thecharge transferred state C.

References
1) M. Kimura et al.: Phys. Rev. A 54, 5019 (1996).
2) S. N. Rai et al.: Int. J. Qantum Chem. 95, 866 (2003).

RIKEN Accel. Prog. Rep. 38 (2005)

Transient field of 24 Mg ions in Gd at high velocities
H. Ueno, A. Yoshimi, Y. Kobayashi, W. Sato,∗1 H. Watanabe,∗2 H. Miyoshi,∗3 K. Shimada,∗3 D. Kameda,∗3
G. Kato,∗3 T. Haseyama, S. Emori,∗3 G. Kijima,∗3 M. Tsukui,∗3 and K. Asahi
Transient ﬁeld (TF) is an eﬀective magnetic ﬁeld
acting on ions passing through ferromagnetic foils. Because of large TF strengths, a large number of nuclear magnetic moments have been measured for shortlifetime excited states on stable nuclei. Such measurements have been carried out using stable-ion beams at
velocities v  Zv0 , since the velocity dependence of
the TF strength BTF is well known in this region.1)
Taking into account the fact that radioactive-isotope
beams produced in the projectile-fragmentation reaction have high velocities v ≥ Zv0 , it is important todetermine the velocity dependence of BTF at a velocity of approximately Zv0 or higher, where Z and v0
denote the atomic number and the Bohr velocity.
The experimental setup, which was developed tocarry out the TF experiments with high-velocity
beams,2,3) was used for the present measurement of
TF strength at the velocities v ∼ Zv0 . A 24 Mg beamobtained from the K = 70 RIKEN AVF cyclotron wasused to bombard a target at the energy E = 7.5A MeV.
The target consisted of two layers, Au and Gd, withthicknesses of 8.1 and 8.4 mg/cm2 , respectively, allowing us to determine TF strength at the beam velocity
v = 14.2v0 . The typical beam current was I = 0.1 pnA.
The I π = 2+ ﬁrst excited state of 24 Mg at the excitation energy Ex = 1.369 MeV, whose g-factor andlifetime are g = +0.51(2) µN and τ = 1.35(3) ps, respectively, was populated by Coulomb scattering from
Au consisting of the upstream layer of the target. The
γ-rays emitted from the excited projectiles were detected coincidentally with scattered particles with apair of NaI(Tl) detectors placed symmetrically at theangle θL = ±50◦ relative to the beam axis.
For a small precession of the nuclear moment, BTF
strength can be determined by combining the obtained
γ-ray angular distribution W (θL ) and double ratio
↑
↓
RLR
/RLR
of the photo-peak counting rates measured
using a pair of NaI detectors in an external magnetic
ﬁeld of Bext = 450 Gauss in the “up” and “down” directions.4) For the reduction in the systematic error
due to beam-proﬁle ﬂuctuation, the Bext direction waschanged periodically every 15 seconds. The obtained
photo-peak counting rates measured at several angles
shown in Fig. 1 were ﬁtted using the Doppler-correctedangular distribution function. The obtained typical γray spectrum is also shown in Fig. 1. We have thus
determined a preliminary value of BTF = 1.2(2) kT.
∗1
∗2
∗3

Department of Chemistry, Osaka University
Department of Nuclear Physics, Australian National University, Australia
Department of Physics, Tokyo Institute of Technology

Fig. 1. A measured γ-ray angular distribution and a typicalγ-ray spectrum for the de-excitation γ rays from the24
2+
Mg. The dotted curve shows the
1 excited state ofresult of peak-fitting analysis.

At lower velocities v  Zv0 , TF strength is approximately given by1)
BTF = a · Z · v/v0 ,(1)

where a is the strength parameter. The a value wasfound to be 17 T for Gd.5) Although the present datashows a large attenuation compared with the BTF
strength obtained from Eq. (1), it is still larger than theprediction of previous models,6) where a sharp decreasein TF strength is predicted at velocities v ≥ Zv0 . The
present result supports a recent model,7) with which
a rather constant or even increasing trend of BTF
strength is predicted at velocities v ≥ Zv0 . Moreover,this observation is in agreement with other measurements obtained at similar velocities.8,9)
In the present experiment, several targets having
various thicknesses of Au layers were also used, whichallowed us to determine the velocity dependence of TF
strength at a velocity of approximately ∼ Zv0 . The
data analysis of these targets is in progress now.
References
1) J. L. Eberhardt et al.: Hyperfine Interact. 3, 195 (1977).
2) H. Ueno et al.: Hyperfine Interact. 136/137, 211(2001).
3) A. Yoshimi et al.: Nucl. Phys. A 738, 519 (2004).
4) M. Forterre et al.: Phys. Rev. C 11, 1976 (1975).
5) G. Jakob et al.: Z. Phys. D 32, 7 (1994).
6) G. Hagelberg et al.: Z. Phys. D 17, 17 (1990).
7) F. Hagelberg et al.: Phys. Rev. C 48, 2230 (1993).
8) K.-H. Speidel et al.: Z. Phys. A 339, 265 (1991).
9) J. Cub et al.: Nucl. Phys. A 549, 304 (1992).

83

RIKEN Accel. Prog. Rep. 38 (2005)

Seismological analyses of acoustic emission in solids
by 95 MeV/u Ar ionsT. Kambara, K. Kageyama,∗ Y. Kanai, T. M. Kojima, Y. Nakai, A. Yoneda, and Y. Yamazaki
Radiation penetrating in solids can produce defects
which generate stress and strain, and thus acoustic
waves in ultrasonic frequencies. We have analyzed experimental acoustic waveforms from solids irradiatedwith fast heavy ions to study dynamical processes in
irradiation eﬀects.
An experimental procedure was reported previously1,2) where polycrystalline metals (Al and Cu) andsingle-crystal BaF2 were irradiated with a single-bunch
beam of 3.8-GeV Ar ions from the RIKEN Ring Cyclotron. Figure 1 shows the geometrical arrangement,
where an ion beam impinges on a sample plate witha thickness of D ≈ 10 mm, and stops at a depth L.
For L we take the range of the 3.8-GeV Ar ion estimated with the TRIM code;3) the L’s are 4.24 mm for
Al, 1.53 mm for Cu and 3.06 mm for BaF2 . The maximum of the energy deposition by the ions, the Bragg
peak, is close to the end of the range, therefore thesource of the wave is assumed to be at the end of theion range and the point on the back plane just above
it is called the epicenter (E). A piezoelectric sensor ison the back of the plate at a distance x from E, at an
azimuth angle θ = arctan[x/(D − L)], and a distancer = (D − L)/ cos θ relative to the source. The sensor
is sensitive only to the component of the displacement
perpendicular to the surface.
Seismological formulations are employed in the analyses. In a bulk solid, there are two modes of acoustic waves, the compressional wave (P wave) and shear
wave (S wave). Since the P wave is always faster thanthe S wave, they can be identiﬁed by their arrival time.
The dynamics of the source of the waves is describedby a 3 × 3 moment tensor. The waves at diﬀerent positions are determined by the moment tensor and a
Green function. Here we use a Green function for inﬁnite, isotropic and homogeneous elastic media. In ionbeam irradiations, axial symmetry permits two typesof source motion; an isotropic expansion and a uniaxial
expansion in the beam direction. The isotropic expansion can generate only isotropic P waves. On the other

hand, the uniaxial expansion generates P and S waves
which have a common time-dependent waveform but
diﬀerent angular dependence and the maximum amplitude of the S wave is larger than that of the P wave.
Under the present experimental conditions, the Pwave amplitude from an isotropic expansion, which isobserved by the sensor, is proportional to cos2 θ. In
the case of uniaxial expansion, the observed P-wave
amplitude is proportional to cos4 θ and the S-wave amplitude to cos2 θ sin2 θ, therefore the observed P-wave
amplitude has maxima at θ = 0◦ and 180◦ , while theS wave has maxima at 45◦ and 135◦ . Since the S wave
is not generated by an isotropic expansion, an S wave
observed at θ ≈ 45◦ should be a clear indication of theanisotropy of the deformation at the source.
The experimental waveforms show clear P-wave signals for all the samples but no obvious structure at
the S-wave arrival time. Figure 2 shows the height of
the ﬁrst peak in the observed P wave as a function ofθ for the three samples. The solid line in the ﬁgure
is a cos2 θ curve which is expected from the isotropic
expansion. There is good agreement between the experimental plots and the curve. This angular dependence and the fact that the S wave is not observed in
the waveforms at θ ≈ 45◦ indicate that the deformation due to the irradiation is almost isotropic in thepresent case.

Fig. 2. Onset peak height of acoustic P wave by sensor
plotted against azimuth angle. Curve is amplitude estimated for P wave from isotropic expansion.

References

Fig. 1. Geometrical relationship between irradiated sample, beam, and sensor.
∗

84

Department of Engineering, Saitama University

1) T. Kambara et al.: Nucl. Instrum. Methods Phys. Res.
B 193, 371 (2002).
2) T. Kambara et al.: RIKEN Accel. Prog. Rep. 36, 97(2003).
3) J. F. Ziegler, J. P. Biersack, and U. Littmark: The Stopping and Range of Ions in Solids (Pergamon Press, New
York, 1985).

RIKEN Accel. Prog. Rep. 38 (2005)

Eﬀect of GeV ion irradiation on magnetic propertyof equiatomic FeRh alloys
M. Fukuzumi,∗1 Y. Chimi,∗2 N. Ishikawa,∗2 F. Ono,∗3 T. Kambara, and A. Iwase∗1
It is well known that equiatomic FeRh alloy showsa first-order magnetic transition near the room temperature, where a low-temperature antiferromagnetic(AF) phase transforms to a high-temperature ferromagnetic (FM) phase.1) Below the transition temperature, this alloy shows atiferromagnetic down to liquidhelium temperature. In this paper, we report that
GeV heavy ion irradiation stabilizes the ferromagnetic
phase of FeRh alloy even at 5 K.
Specimens used for the present experiment were
Fe-50at.%Rh alloys, the dimensions of which were
5.0 mm × 5.0 mm × 0.3 mm. The X-ray profiles ofthe specimens showed that most peaks could be identified as corresponding to a B2 ordered structure.
The specimens were irradiated at room temperature
with 3.5 GeV (26 MeV/u) Xe ions at the fluence of
1×1012 /cm2 , 2.5×1012 /cm2 or 5×1012 /cm2 using the
RIKEN Ring Cyclotron. After irradiation, the magnetization of the specimens was measured as a functionof temperature under the magnetic field of 0.6 T usinga Quantum Design SQUID magnetometer.
Figure 1 shows the temperature dependence of magnetization for the unirradiated specimen and those irradiated with Xe ions. The figure indicates a largechange in magnetization near 300 K. This magnetization change corresponds to the magnetic transition
from AF to FM phase. For the irradiated specimens,
besides a large change in magnetization near room
temperature, we can see a finite magnetization at low
temperatures. As the projected range of 3.5 GeV Xeions is smaller than the specimen thickness, the irradiated region is localized only near the surface, and somepart of the specimen remains unirradiated. Therefore,
the large change in magnetization near room temperature for the irradiated specimens indicates the AF-FM
transition in the unirradiated region, and the finite themagnetization at the low temperatures means that theferromagnetic phase is induced near the surface by irradiation. The irradiation-induced magnetization is stillobserved even at 5 K. In Fig. 2, the values of the magnetization at 5 K are plotted as a function of ion fluence. As can be seen in the figure, the magnetization
increases with increasing ion fluence.
Although the reason why the ferromagnetic phase isstabilized below room temperature by the Xe ion irradiation still remains uncertain, the magnetic property
of non-equiatomic Fe-Rh alloys may give us a clue tothe solution. The magnetic properties of Fe-Rh alloys
strongly depend on the composition of Fe and Rh.2)
The increase in Fe content by only 1–2% makes Fe50at.%Rh alloys ferromagnetic even at low temperatures. Such a non-equiatomic Fe-50at.%Rh alloy includes some lattice disordering such as Rh atom vacancies and anti-site defects. Therefore, the present
result suggests that irradiation-induced lattice disordering plays an important role in the stabilization of
the ferromagnetic phase of Fe-50at.%Rh alloy.

Fig. 2. Magnetization at 5 K as a function of ion fluence.

References
Fig. 1. Temperature dependence of magnetization for unirradiated and 3.54 GeV Xe ion-irradiated Fe-50at.%Rh
specimens under magnetic field of 0.6 T.
∗1
∗2
∗3

1) J. S. Kouvel and C. C. Hartelius: J. Appl. Phys. Suppl.
No. 33, 1343 (1962).
2) L. Pal, G. Zimmer, M. P. Horvath, and J. Paitz: J. de
Phys. 32, C1-861 (1971).

Osaka Prefecture University
Japan Atomic Energy Research InstituteOkayama University

85

RIKEN Accel. Prog. Rep. 38 (2005)

Single-event burnout of super-junction power MOSFETs
N. Ikeda,∗1 S. Kuboyama,∗1 K. Oka,∗1 H. Ohira,∗2 H. Otomo,∗2 O. Shimada,∗2 N. Inabe and M. Kase
A power MOSFET (metal-oxide-semiconductorﬁeld-eﬀect transistor) is a key device in a power circuitthat has a low ON-resistance and a fast switching. A
MOSFET to be used in space is required to have radiation hardness. Protons, heavy ions and other particles
in space could cause single-event eﬀects and lead tosemiconductor device malfunction or failure. Singleevent burnout (SEB) is the main concern regarding
power MOSFETs. SEB is triggered by a heavy ion
passing through the device when it is oﬀ. A transientcurrent by such an ion turn on a parasitic bipolar transistor, which results in the burning out of the device
and its possible destruction.1)
Recently, a new type of MOSFET called SuperJunction MOSFET (SJ-MOSFET) has been realized
for high voltage usage. SJ-MOSFET has a new structure and has a considerably lower ON-resistance thanstandard MOSFETs. Although it is an attractive feature, no one has examined its SEB tolerance which isvery important for space application.
JAXA (Japan Aerospace Exploration Agency) has
conducted 58 Ni19+ irradiation tests of a 600 V SJMOSFET using the RIKEN Ring Cyclotron to determine its SEB tolerance. A standard MOSFET withalmost the same speciﬁcation was also irradiated asa reference. Energy, LET and the projected range ofions in a device were 673 MeV, 19 MeV/(mg/cm2 ), and122 µm, respectively.
The EPICS (Energetic Particle Induced Charge
Spectroscopy) system developed by JAXA was introduced to observe SEB, and the spectra of collectedcharges were examined in the same manner as previous study.2) Typically, two peaks are observed in the
spectra, which are here called the ﬁrst peak and thesecond peak. A larger charge collection of the second
peak implies less SEB tolerance.
Figure 1 shows the spectra of collected charges andthe number of SEB occurrences of both types of MOSFET. SEB was observed at lower VDS in the SJMOSFET (390 V) than in the standard MOSFET(410 V). Figure 2 shows the collected charge of thesecond peak to VDS of both types of MOSFET. Although the collected charges of the SJ-MOSFET were
smaller at lower VDS than those of the standard MOSFET, they were almost the same in quantity and the

∗1
∗2

86

Japan Aerospace Exploration Agency
Ryoei Technica Company(a) SJ-MOSFET(b) standard MOSFET

Fig. 1. SEB spectra and number of SEB occurrences of an
SJ-MOSFET and a standard MOSFET. SEB occurredat lower VDS in SJ-MOSFET.

Fig. 2. Collected charges of second peak to VDS of bothtypes of MOSFET. Collected charge of the second peakof SJ-MOSFET was almost the same as that of standard
MOSFET at high voltage, and the gradient of the curve
was larger in SJ-MOSFET at high voltage.

gradient of the curve of the SJ-MOSFET was larger
at higher voltages. These results suggest that the SJMOSFET is less immune to SEB.
References
1) JAERI and NASDA Joint Research Report, Vol. 2(1999), p. II-9.
2) N. Ikeda et al.: RIKEN Acce. Prog. Rep. 37, 98 (2003).

RIKEN Accel. Prog. Rep. 38 (2005)

Ion-track continuum: Its finding and material dependence
K. Kimura,∗ M. Koshimizu,∗ K. Asai,∗ H. Ryuto, and M. Kase
We have observed ultrafast luminescence (UFL, τ <100 ps) from incipient heavy-ion track cores in insulator crystals such as alkali halides, metal oxides, andalkaline-earth halides, from measurements of decay
curves and time-resolved spectra (TRS) with a time
resolution of 85 ps.1) UFL can be detected using not
only fast sensitive detection techniques but also anappropriate beam condition to suppress the formation of energetic secondary electrons, that is, to makethe track-core eﬀects prominent. UFL is the ﬁrst observed collective-behavior of an ion track. UFL wascharacterized by the insensitivity to temperature, nonlinearity of excitation-density dependence, and so on.
Of these characteristics, the material dependence is described in this report. This is an important characteristic that distinguish UFL from the known radiationinduced continuum such as Bremsstrahlung, Cerenkov
radiations, transition radiations, and intra band transitions. UFL in insulators is observable only becauseof extremely dense-energy deposition given by heavyions, but seams impossible to observe using othersources, such as a laser or electron beam. Therefore,
we refer to UFL as the ion-track continuum hereafter.
Figures 1 and 2 show three-dimensional displays ofwavelength-dependent decay curves of luminescence in
Xe-ion bombarded single crystals of RbI and MgO at
close to 4.2 K, respectively. There exists commonly theshort-lived continuum extending from the vacuum UV
to the visible range. Experimental results suggest thatthe continuum originates from radiative recombination
forced by interaction among adjoining e-h pairs.1,2)
The structure of the continuum can be explained by
self-hole trapping. Untill the group of ejected electrons
returns to the group of holes located along the trackcenter, holes can be trapped since the hole trapping
is so fast as to be complete in 2 ps.2) The recombination luminescence of e-h pairs decreases the energy gap
according to the depth of the hole-trapping, namely
according to the Stokes shifts. Also, the continuum
has higher density of states at the trapped holes tomake a structure. Actually, the continuum has peaks
at wavelengths close to self-trapped excitons (STE).
Thus, the continuum may look like the hot luminescence band of the STE. This fact is distinct in alkali halides in which knowledge about the STE is complete.2) As for RbI, STEs are known to have peaks at
318, 400, and 539 nm. The ion-track continuum has anevident peak around 318 nm although the continuumand STE luminescence are superposed and also projections near 400 and 539 nm although they are weak.
MgO has an intense band at 180 nm in the vacuum∗

Department of Applied Chemistry, Tohoku University

Fig. 1. Wavelength-dependent luminescence decay curvesof Xe-ion bombarded single crystals of RbI at 6 K.

Fig. 2. Wavelength-dependent luminescence decay curvesof Xe-ion bombarded single crystals of MgO at 6 K.

UV region (Fig. 2). This band can be ascribed to theion-track continuum. Moreover, was found the important fact that the continuum precedes the free-exciton
formation of which luminescence at 162.4 nm is principal in case of photon- or electron excitations. This
result is proved from the fact that Xe-irradiation gives
the continuum but no free exciton luminescence andalso the fact that at room temperature, Ar-irradiation
gives the intense 180-nm band but the free-excitonband disappeared. According to the results obtained
for alkali halides, the 180-nm band implies the holetrapping with the depth corresponding to Stokes shift,although the depth is much shallower compared with87

alkali halides. Some references suggest that STE luminescence exists at 180 nm3,4) , although its intensity is
negligibly small. On the other hand, the 180-nm bandis diﬀerent on some points from e-h plasmas known for
semiconductors: the shift of the latter much smaller
and is not Stokes shift but due to binding energy between e-h pairs. The former emission occurs at muchhigher density of e-h pairs. Now, a signiﬁcant procedure to predict ﬁnal products emerged. In case of
excitation beyond ionization, one can predict radiative
or non-radiative relaxation processes or products formations by considering likely reactions between holes
and lattice during the travel of ejected electrons, that is
independent of any source such as photons, electrons,
or ions. For examples, in MgO, the hole is O− and thevalence state is O2− ; For RbI, the hole I0 and thevalence I− .
Lastly, the largest eﬃciency of alkali halides are
given by iodides such as RbI and CsI, and with decreasing mass of the halogens, the eﬃciencies decreaseby three orders of magnitude untill ﬂuorides. The eﬃciency is almost independent of the type of metal ions.

88

This independence may be due to large spin-orbit coupling of heavy halogens. On the other hand, the iontrack continuum can be scarcely observed for SiO2, andcannot be observed at all for diamonds. Holes in ionic
crystals X− is isolated, that is, the hole has no network of phonons, whereas holes in a covalent crystal
keeps bonds with surrounding and then has a networkof phonons. The network works as energy dispersion
paths such that excess energy is not necessary to rely
photoemission.
References
1) K. Kimura, J. Kaneko, S. Sharma, W. Hong, and N.
Itoh: Phys. Rev. B 60, 12626 (1999); K. Kimura, S.
Sharma, and A. Popov: Radiat. Meas. 34, 99 (2001);
Nucl. Instrum. Methods Phys. Res. B 191, 48 (2002).
2) K. Kimura: Nucl. Instrum. Methods Phys. Res. B 212,123 (2003).
3) Z. A. Rachiko and J. A. Valbis: Phys. Stat. Sol. (b) 98,
161 (1979).
4) M. Kirm, S. Vielhauser, G. Zimmerer, A. Lushchik, and
Ch. Lushchik: Surf. Rev. Lett. 9, 1363 (2002).

RIKEN Accel. Prog. Rep. 38 (2005)

Time-resolved luminescence spectra of ion-irradiatedalpha-alumina in VUV region
M. Koshimizu,∗ K. Kimura, H. Ryuto, K. Asai,∗ and M. Kase
The irradiation eﬀects of heavy ions in insulators
have been attracting considerable interest. It has been
pointed out that self-trapped excitons (STEs) play a
crucial role in the irradiation eﬀects, particularly inthe formation of an ion track.1) In our previous study
on MgO, however, it was shown that the luminescenceband due to free excitons disappeared and the intensityof the peak possibly due to dense e-h pairs with somelattice relaxation increased at higher excitation density,2) indicating that the formation of excitons frome-h pairs does not occur before relaxation of holes accompanying lattice deformation. In order to further
investigate the inﬂuence of the hole relaxation on the
dynamics of the electron-lattice system under highdensity excitation, we analyzed the high-density excitation eﬀects in alpha-alumina, where the relaxationof holes or excitons has been discussed by many researchers.
Time-resolved luminescence spectra of alphaalumina under irradiation of Xe ions at the energyof 2.0 MeV/nucleon in the VUV region are shown in
Fig. 1. The time-resolved spectra at various temperatures are characterized by two decaying components.
The fast component has a lifetime of approximately
100 ps, which is independent of temperature. Also,
its intensity seems rather insensitive to temperature.
On the other hand, the temperature-dependence of theslow component is complicated. Below 15 K, the lifetime of the slow component increases with increasing
temperature, whereas it decreases as the temperature
increases above 77 K, and the slow component almost
disappears at 300 K. The fast component is broadly
distributed beyond 200 nm and has a peak at a longer
wavelength than the slow component.
The characteristics of the fast component are exactly
analogous to the fast luminescence band observed for
MgO2) and other alkali-halides3–5) under heavy-ion irradiation. The possible origin of these bands is thedense e-h pairs analogous to the electron-hole plasma
in semiconductors, accompanied by some lattice relaxation similar to polarons. A gigantic oscillator strengthis expected for such dense e-h pairs analogous to thecase of semiconductors, which explains the extremely
fast decay of these bands. These bands cannot be seenin the case of electron irradiation.
The temperature dependence of the slow component,on the other hand, is similar to the previous result
under electron irradiation, where the eﬃciency of theband at 7.5 eV reached the maximum value at approximately 40 K.6) The origin of this band is certainly ascribed to the STEs6) or self-shrunk excitons,7) which
are STEs when electrons or holes do not individually
undergo self-trapping. However, the decay rate of theslow component is even faster than the fastest component of the STE band observed under electron irradiation. This diﬀerence is possibly due to nonradiativeannihilation due to STE-STE interaction, which is reported for ion-irradiated BaF2 .8)
Interestingly, the peak of the fast band of alphaalumina is rather clear compared to that of alkalihalide, and is located on the longer-wavelength sideof the STE band. This result strongly suggests thatthe the origin of the fast band is accompanied by asimilar lattice deformation to that of the STE.
References

Fig. 1. Time-resolved luminescence spectra of alphaalumina at 3.3 and 300 K.
∗1

Department of Applied Chemistry, Tohoku University

1) N. Itoh and A. M. Stoneham: Nucl. Instrum. Methods
Phys. Res. B 146, 362 (1998).
2) K. Kimura, M. Koshimizu, K. Asai, and M. Kase:
RIKEN Accel. Prog. Rep. 37, 99 (2004).
3) K. Kimura et al.: Radiat. Meas. 34, 99 (2001).
4) K. Kimura et al.: Nucl. Instrum. Methods Phys. Res. B
191, 48 (2002).
5) K. Kimura: Nucl. Instrum. Methods Phys. Res. B 212,123 (2003).
6) J. Valbis and N. Itoh: Radiat. Eﬀ. Defects Solids 116,
171 (1991).
7) M. Kirm et al.: Phys. Rev. B 60, 502 (1999).
8) K. Kimura et al.: Phys. Rev. B 58, 6981 (1998).

89

RIKEN Accel. Prog. Rep. 38 (2005)

Coincidence measurements between L X-rays and final charge statesof Ar ions after passing Ni microcapillary
Y. Kanai, Y. Nakai, Y. Iwai, T. Ikeda, M. Hoshino, K. Nishio,∗ H. Masuda,∗ and Y. Yamazaki
A slow highly charged ion passing through a microcapillary target captures target valence electrons into
high-n orbitals while keeping inner shell vacancies.1)
To study the production and decay processes of suchhighly excited ions, we have measured the L X-ray
spectra in coincidence with the ﬁnal charge states of
Ar ions after passing a Ni microcapillary by changing the number of initial inner-shell (L-shell) vacancies.2,3) The experiments were carried out at the Slow
Highly Charged Ion Facility at RIKEN.4) 2.8 keV/u
Arqi+ (qi = 14, 13, 11 and 9) ions from a 14.5 GHz
ECR ions source were used. The beams impinged on a
Ni microcapillary target5) along the capillary axis. A
Si(Li) X-ray detector, which was placed at 90◦ to thebeam axis, detected the X-rays emitted from the excited Ar ions after passing the microcapillary target.
We have obtained L X-ray spectra, their shapes andenergy positions, and X-ray yields as functions of delay time td , as well as integrated delayed X-ray yields,
in coincidence with the ﬁnal charge states qf of Ar ions.
The integrated delayed X-ray yield η (td , qf ) is given Tζ(t, qf )dt,
(1)
η(td , qf ) =td

where ζ(t, qf ) is the intensity of the L X-rays emitted
from the ions with qf at t after passing the target,
and T is the maximum observable delay time whereT = 14 ns in our experiments.
In this report, we summarize our experimental results:(1) the peak energy of the coincidence X-ray spectrum dη/dE shifts to a lower energy region with decreasing ﬁnal charge states qf , i.e., with increasing
number of electrons being stabilized Ns = (qi − qf ),and does not depend on the delay time td ,(2) the shape of the X-ray spectrum does not depend
on td ,
(3) the integrated delayed X-ray yields η(td , qf ) for
single-electron-stabilized ions (Ns = 1) decrease more
rapidly than those for multielectron-stabilized ions(Ns ≥ 2), except for qi = 9,(4) the integrated delayed X-ray yields show a long
decay time (∼ ns), and(5) the integrated delayed X-ray yields for td = 0 ns
are almost the same as those for the ions, which havemultiple L-shell holes at the moment of the X-ray emission.
Experimental results (1) and (2) indicate that thecore charge states qc of Ar ions at the moment of the∗90

Department of Applied Chemistry, Tokyo Metropolitan University

L X-ray emission depend only on the ﬁnal charge state
qf ; qc = qf +1 = qi −(Ns −1), and do not depend on the
delay time td after the target. These may be explainedby the fact that the (Ns − 1) of the L-shell holes are
ﬁlled by a cascade of Auger processes rapidly ( ns)
and then the Ns th hole is ﬁlled by emitting L X-rays.
Experimental result (3) may be attributed to theradiative decay time of the Ns th electron from theexcited state to the M shell as follws. The observed
decay time τo of X-ray intensity is given by τo =
τA + τd + τL X-ray , where τA is the decay time for acascade of Auger processes to ﬁll the (Ns − 1) holes
leaving one electron in an excited state (n0 , l0 ), τd isthe decay time for a cascade of radiative transitions
from the (n0 , l0 ) state to n = 3 states, τL X-ray is the
decay time of the Ns th L-shell hole ﬁlled by the M-shellelectron by emitting L X-rays. In general, the Augercascade processes of multiply excited states are rapid,
which is also indicated by our experimental results (1)and (2). Thus, τo can be reduced to τo ∼τd + τL X-ray .
It is diﬃcult to explain the diﬀerence between the observed decay time for Ns = 1 and that for Ns ≥ 2 using
the diﬀerence in τL X-ray ; because there is no reason
that the τL X-ray for Ns = 1 must be always shorter
than that for Ns ≥ 2. Therefore, we consider that τd
is diﬀerent between the Ns = 1 and Ns ≥ 2 cases.
If the excited state (n0 , l0 ) has small angular momenta, such as s, p and d, the excited electron rapidly
decays into the L-shell hole by emitting X-rays. Thus,
our observed ∼ ns decay time (experimental result (4))
should be related to the higher angular momentum excited states l0  1.
Based on the image mentioned above, (a) if the Ns thelectron is left in the excited state by the ﬁnal Augertransition, the Ar ion emits L X-rays. On the other
hand, (b) if the Ns th electron ﬁlls an L-shell hole by
the ﬁnal Auger transition, the Ar ion does not emit
L X-rays. The branching ratio between processes (a)and (b) depends on the electronic conﬁguration before
the ﬁnal Auger transition. Experimental result (5) indicates that the branching ratio is almost the same forthe ions with multiple L-shell holes at the moment of
the L X-ray emission.
References
1) S. Ninomiya et al.: Phys. Rev. Lett. 78, 4557 (1997).
2) Y. Kanai et al.: RIKEN Accel. Prog. Rep. 36, 109(2003).
3) Y. Kanai et al.: RIKEN Accel. Prog. Rep. 37, 104(2004).
4) Y. Kanai et al.: Phys. Scr. T 92, 467 (2001).
5) Y. Masuda et al.: Appl. Phys. Lett. 71, 2770 (1997).

RIKEN Accel. Prog. Rep. 38 (2005)

Coincidence measurements of X rays and final charge statesof N ions transmitted through Ni microcapillaries
Y. Iwai, Y. Kanai, Y. Nakai, T. Ikeda, M. Hoshino, H. Oyama, K. Ando,
H. Masuda,∗1 K. Nishio,∗1 H. A. Torii,∗2 K. Komaki,∗2 and Y. Yamazaki
K X rays emitted from 2.1 keV/u N ions which
passed through a thin Ni microcapillary foil were measured in coincidence with a ﬁnal charge state qf in thecases of incident charge states of qi = 7 and 6. Ninomiya et al. measured X rays in coincidence with aﬁnal charge state qf for N6+ ions incident on the microcapillary target.1) They found that the K-hole lifetimes were ∼ns even when several electrons were in the
L shell. In this work, N7+ ions as well as N6+ ions wereselected as projectiles so that the relaxation dynamics
with diﬀerent numbers of inner-shell vacancies can bestudied.
Ions (2.1 keV/u N6,7+ ) are supplied by a 14.5 GHz
Caprice electron cyclotron resonance ion source in
RIKEN.2) The microcapillary target was ∼1 mm2 inarea with a thickness of ∼1 µm and had a multitudeof straight holes of ∼200 nm in diameter.3) A windowless Si(Li) X-ray detector was installed at 90 degrees
with respect to the incident ion beam. A shield locatedbetween the ion beam and the detector was movable
along the ion beam and was used to limit the detection region of delayed X rays. When the shield is located at z, the detector can capture X rays emitted attime 17 ns > t > z /v, where v is the projectile velocity. The ions passed through the microcapillary target
were charge-state analyzed with an electrostatic deﬂector and detected by a channel electron multiplier.4)
The solid and open circles in Fig. 1 are for the coincidence spectra with the X-ray detector for (qi ,qf )= (7,6) setting the shield at 0 mm and 1 mm, respectively. The solid line shows the spectrum measured
with a high-resolution spectrometer for qi = 7 immediately downstream of the Ni microcapillary foil.5) It isthen concluded that the coincidence X rays with (7,6)
were primarily attributed to 2p - 1s transition.
Figure 2 shows the coincidence X-ray yields as afunction of the shield position. It is seen that the
X-ray yield for (7,5) was almost the same with thatfor (6,5), and the same is true for (7,4) and (6,4),
i.e., the coincidence X-ray yields did not depend on
the number of K-shell holes of the incident ions buton the ﬁnal charge state qf . The coincidence X-ray
yield for (7,6) decreased faster than those with other(qi ,qf )-combinations. The solid line in Fig. 2 shows
the integrated K X-ray yield obtained via the cascadecalculation of one electron ion initially populated ac∗1
∗2

Department of Applied Chemistry, Graduate School of Engineering, Tokyo Metropolitan University
Institute of Physics, Graduate School of Arts and Sciences,
University of Tokyo

Fig. 1. Energy spectra of nitrogen K X rays with (qi , qf )= (7,6). A spectrum of X rays measured with a highresolution soft X-ray spectrometer is shown for comparison.5) The bars with transition terms show transitionenergies.

Fig. 2. Integrated coincidence X-ray yields as a function of
the shield position for incident and final charge state
combinations. The solid line shows the integrated K
X-ray yield obtained via cascade calculation.

cording to the report of visible light measurement.6) It
is seen that the calculation can crudely reproduce theexperimental result for (7,6).
References
1) S. Ninomiya et al.: Phys. Rev. Lett. 78, 4557 (1997).
2) Y. Kanai et al.: Phys. Scr. T 92, 467 (2001).
3) H. Masuda et al.: Appl. Phys. Lett. 71, 2770 (1997).
4) Y. Kanai et al.: Nucl. Instrum. Methods Phys. Res. B,
in print.
5) Y. Iwai et al.: Nucl. Instrum. Methods Phys. Res. B
193, 504 (2002).
6) Y. Morishita et al.: Phys. Rev. A 70, 012902 (2004).

91

RIKEN Accel. Prog. Rep. 38 (2005)

Single and double electron capture processes inslow N5+ -He collisions
Y. Miyamoto,∗ M. Hoshino, N. Tanaka,∗ K. Yamashita,∗ Y. Kanai, M. Kitajima,∗
Y. Nakai, H. Tanaka,∗ and Y. Yamazaki
The angle-resolved energy gain spectra of N5+ -He
collisions have been measured at an impact energy of
140 eV/q. Several experimental1–6) and theoretical7)
works on N5+ -He collisions have been reported for single electron capture above 1 keV/q. Partial cross sections for single electron capture have been determinedby vuv photon emission spectroscopy.8–10) It has beenfound that the dominant ﬁnal states are N4+ (1s2 3s 2 S),
N4+ (1s2 3p 2 P) and N4+ (1s2 3d 2 D). However, there has
been no state-selective measurement of double capturein the low energy region. Therefore, we measured thestate-selective angular distributions at 140 eV/q.
The experiment was carried out using a crossedbeam apparatus, which was positioned at the beamline BL2 of the 14.5 GHz Caprice-type ECRIS in theslow highly charged ion beam facility. Details of our experimental setup have been described elsewhere.11,12)
The typical current and energy resolution of the energy selected N5+ beam at 140 eV/q were 50 pA and
1 eV/q, respectively.
The angle-resolved energy gain spectra for single anddouble electron capture were measured at the scattering angle θ of 0◦ –10◦ with a 0.5◦ step. From theseenergy gain spectra we constructed a 2D contour mapof the scattered ion intensity with respect to the energy gain ∆E and scattering angle θ of projectiles in
the laboratory system. The kinematic relationship between ∆E and θ can be derived from the energy andmomentum conservation for a Q-value, where the Qvalue is the energy release of the reaction. When the
Q-value is speciﬁed, a unique curve is drawn on the
2D contour map. This curve shows the relationshipbetween ∆E and θ of the scattering ions in a certain
ﬁnal channel.
Figure 1 shows the 2D contour map of N3+ ions produced in N5+ -He collisions at the energy of 140 eV/q.
Solid curves show the relationship between ∆E andθ for the ﬁnal channels N3+ (1s2 2s3l), N3+ (1s2 2s4l),
N3+ (1s2 2p3l), N3+ (1s2 2s5l), N3+ (1s2 2s8l) and N3+(1s2 2p4l). In Fig. 1, double electron capture into theN3+ (1s2 2snl) state (n = 3–5) and the N3+ (1s2 2pn l)state (n = 3, 4) are observed. At smaller scattering
angles, electron capture into the N3+ (1s2 2s3l) state,
the N3+ (1s2 2s4l) state and the N3+ (1s2 2p4l) stateshow strong intensities. At large scattering angles elec-∗

92

Department of Physics, Sophia University

Fig. 1. 2D contour map of N3+ ions from double electron
capture for N5+ -He at collision energy of 140 eV/q.

tron capture into the N3+ (1s2 2s5l) state shows strong
intensities. The intensities of the peaks of each ﬁnal
state markedly change with changing scattering angle. By adopting the classical over-barrier model,13)
the ﬁnal states can be predicted as N4+ (1s2 3l) andN3+ (1s2 2l3l ) for single and double electron capture,
respectively. However, there are discrepancies between
the model and our results and we observed many more
ﬁnal states than predicted by the model.
References
1) K. Okuno et al.: Phys. Rev. A 28, 127 (1983).
2) W. Waggoner et al.: Phys. Rev. A 37, 2386 (1987).
3) T. Iwai et al.: Phys. Rev. A 26, 105 (1982).
4) L. D. Gardner et al.: Phys. Rev. A 20, 766 (1979).
5) D. H Grandall: Phys. Rev. A 16, 958 (1977).
6) K. Ishii et al.: Phys. Rev. A 70, 042716 (2004).
7) M. C. Bacchus-Montabonel: Phys. Rev. A 40, 6088
(1989).
8) J. P. M. Beijers et al.: Phys. Rev. A 49, 363 (1944).
9) P. H. Cotte et al.: Nucl. Instrum. Methods Phys. Res.
B 9, 743 (1985).
10) D. Dijkkamp et al.: J. Phys. B 18, 4763 (1985).
11) Y. Kanai et al.: Phys. Scr. T 92, 467 (2001).
12) M. Hoshino et al.: Nucl. Instrum. Methods Phys. Res.
B 205, 568 (2003).
13) A. Neihaus.: J. Phys. B 19, 2925 (1986).

RIKEN Accel. Prog. Rep. 38 (2005)

Theoretical study of electron capture in collisions of C4+ with He
L. Pichl,∗1 R. Suzuki,∗2 M. Hoshino, Y. Li,∗3 R. J. Buenker,∗3 M. Kimura,∗4 and Y. Yamazaki
Although the theoretical formalism of ion-atom collisions has been well established for a long time,1) various cross-section calculations for electron capture relevant to fusion research, plasma diagnostics or astrophysics remain to be performed. The system of C4+
colliding with He is theoretically interesting becauseof its exothermic initial channel which intersects withnumerous single- and double-capture states at shorter
distances, and also the unusual dominance of double
electron capture process. In addition, the single capture states exhibit long-range Coulomb asymptotics
that eﬀects the boundary conditions. The CHe4+ system also serves as a particular benchmark for measurements and theory calculations.2)
In order to compare to recent measurements in
RIKEN3) which reported angular diﬀerential cross sections for double electron capture (energy 240, 320 and
440 eV) we have computed the electronic potential energy curves and radial couplings in the singlet state
manifold. These are used in subsequent close-coupling
calculations. Because of the relatively high energy, alarge number of partial waves is required. Since theasymptotic energy level separation compares to the kinetic energy, a common trajectory approximation does
not apply. The calculated values of angular-diﬀerential
cross sections are sensitive to the details of the potential energy curves.
The electronic potential energy curves (PEC) andradial couplings were computed with the multireference single- and double-excitation conﬁgurationinteraction method (MRD-CI4) ). A standard gaussian basis set has been used ([5s4p3d2f1g] for C and[4s3p2d1f] for He) and augmented by diﬀuse functions.
The energy selection threshold and number of conﬁgurations is 0.1 µEh and 500,000, respectively. Radial
couplings are calculated by using numerical derivativesof the CI wave functions. The PEC and couplings deﬁne the diabatic representation of the system. Our
ab initio results are shown in Fig. 1; the electronic
states are assigned to carbon ions in increasing order(at R = 100 a.u.) as 1s2 2s1 (He+ ), 1s2 2s2 (main double capture channel), 1s2 2p1 (He+ ), 1s2 2s1 2p1 , 1s2 2p2 ,1s2 2p2 , 1s2 2s1 3s1 , 1s2 3s1 (He+ ), and 1s2 (He) (the initial state for electron capture in C4+ |He collision).
Note the long-range series of sharp near-diabatic crossings along the initial channel in the ﬁgure.

∗1
∗2
∗3
∗4

Fig. 1. Potential energy curves of CHe4+ system.

Our ﬁrst results of quantal scattering calculations
indicate a good qualitative agreement with the experimental angular-diﬀerential cross sections.3) Stueckelberg oscillations are seen as a result of interference
between electronic states. The double capture crosssections appear to include both the direct mechanism
as well as a sequence of the single capture processes.
A comparison with other theoretical calculations is inprogress.
References
1) M. Kimura and N. F. Lane: Adv. At. Mol. Opt. Phys.
26, 79 (1989).
2) N. Keller, L. R. Andersson, R. D. Miller et al.: Phys.
Rev. A 48, 3684 (1993).
3) M. Hoshino, M. Kitajima, Y. Kanai, Y. Nakai, H.
Tanaka, and Y. Yamazaki: Phys. Scr. T 92, 339 (2001).
4) R. J. Buenker and R. A. Phillips: J. Mol. Struct.
Theochem 123, 291 (1985).

Department of Computer Software, University of Aizu
Computer Center, Hitotsubashi University
Bergische Universitaet Wuppertal, Germany
Graduate School of Sciences, Kyushu University

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RIKEN Accel. Prog. Rep. 38 (2005)

Multiple-electron processes in close single collisions of
Neq+ (q = 1, 2, and 3) with Ar at 5 keV
M. Hoshino, T. Kambara, Y. Kanai, R. Schuch,∗ and Y. Yamazaki
A simpliﬁed description of electron transfer in highly
charged ion (HCI)-atom collisions is given by the classical over barrier model,1) which has been successfully
describing single electron transfer in peripheral collisions, where most of the cross section can be found. Avery small amount of the diﬀerential cross section is ata large scattering angle. Therefore, multiple electron
processes, which include not only electron capture but
also ionization processes, can be expected to become
dominant.
To study the multiple electron processes in largeangle scattering, we have measured the charge statecorrelation between the scattered and recoil ions as afunction of incident charge states in collisions of 5 keV
Neq+ (q = 1, 2, and 3) with Ar atoms. The corresponding distance of the closest approach is estimated to beabout 0.6 a.u. using the screened Coulomb potential,2)which is by one order of magnitude smaller than thecritical distance of electron capture from the classicalover barrier model.
The experiment was carried out at the slow highly
charged ion-beam facility. A 5 keV Neq+ (q = 1, 2, and
3) beam from the 14.5 GHz Caprice ECR ion source
was collimated on a localized Ar target from a needle. We used the experimental apparatus reported lastyear.3) The scattered Ne and recoil Ar ions were detected at 27◦ and 70◦ as expected from the kinematics
of elastic scattering, which corresponds to 40◦ in the
CM system. Each ion detection telescope consists of atime-of-ﬂight (TOF) drift tube and a two-dimensional
position-sensitive detector with a microchannel plate.
For each coincidence event, the positions of the scattered and recoil ions and the diﬀerence of the TOF values (∆TOF) between these ions were recorded. With
the drift tube biased on the electrostatic potential, one
can modulate the ion velocity and determine the outgoing charge states using ∆TOF.
In Fig. 1, the charge state distributions of Ne and Ar
ions are shown for q = 1, 2, and 3. For q = 1, the fraction of pure ionization (qNe = 1) was found to be thelargest. In the case of q = 2, the recoil charge states
showed broader distributions, and single-electron capture with target ionization channels (qNe = 1 andqAr > 1) were the main channels. In q = 3, a singleelectron capture with triple target ionization channel was the major channel. Double-electron capturechannel (qNe = 1) and pure target ionization channel∗

94

Atomic Physics, Stockholm University, Sweden

Fig. 1. Charge state distributions of Ne and Ar ions in
Neq+ (q = 1, 2, and 3)-Ar collisions at 5 keV. •: total,◦: qNe = 0, : qNe = 1, : qNe = 2, ✸: qNe = 3.

(qNe = 3) were also observed.
Figure 2 shows the mean charge states of both thescattered (q Ne ) and recoil (q Ar ) ions as functions ofincident charge state q, and the number of emitted
electrons (qe = q Ne + q Ar − q). The mean charge statesof the scattered and recoil ions increase with q, while
the number of emitted electrons qe appears almost independent of q.

Fig. 2. Incident charge dependence of the mean charge
state of the scattered and recoil ions, and the emitted
electron number for q = 1, 2, and 3.

References
1) A. Niehaus: J. Phys. B 19, 2925 (1986).
2) E. Everhart, G. Stone, and R. J. Carbone: Phys. Rev.
99, 1287 (1955).
3) M. Hoshino et al.: RIKEN Accel. Prog. Rep. 37, 105(2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Scheme for highly charged ion cooling with positron and electron
N. Oshima, M. Niigaki, A. Mohri, Y. Kanai, Y. Nakai, K. Komaki,∗ and Y. Yamazaki
The developments of electron cyclotron resonance(ECR) ion source and electron beam ion source (EBIS)
have opened a new research ﬁeld of slow highly charged
ions (HCIs). However, the accessible kinetic energy(1–10 eV/q) is still not necessarily satisfactorily low,
and there are strong demands to develop an eﬃcienttechnique to store and cool HCIs to 0.1 eV/q.1–6)
Electron and positron cooling techniques are useful
methods to produce cold HCI beams. Charged particles in a strong magnetic ﬁeld lose their kinetic energies via synchrotron radiation, the rate of which isinversely proportional to the particle mass cubed, i.e.,
the rates for positrons and electrons are more than 1010
times faster than those of ions. Actually, only electrons and positrons can be cooled via synchrotron radiation within some reasonable time for a magnetic ﬁeld
available on earth. Heavy particles can accordingly
be cooled sympathetically if they are stored simultaneously with electrons and/or positrons in a strong
magnetic ﬁeld.
In principle, positrons are better coolants than electrons because HCIs are not lost due to recombination
during cooling. On the other hand, the number ofelectrons (109 –1010 ) in a trap4) can be practically a
few orders of magnitude larger than the number of
positrons (107 –108 ),7) and the electron cooling scheme
has a great advantage with respect to cooling time andaccordingly the loss due to recombination with residual gases. In order to selectively utilize the favorable
features of positrons and electrons and suppress disadvantages, a new scheme to cool HCIs is consideredutilizing electrons and positrons simultaneously.5,8)
The considered cooling procedure is schematicallyshown in Fig. 1, which consists of the (a) formationof electron and positron plasmas,4,7) (b) simultaneous cooling of pulse-injected HCIs with electron andpositron plasmas, and (c) extraction of cooled HCIs
by the ramping of trapping potential.
Our simple evaluation showed that the required cooling time of HCIs from 10 keV/q to 0.1 eV/q with the
new scheme could be on the order of 1 second, which
is 10 times faster than the that by pure positron cooling.8) Therefore, the loss of HCIs due to recombination
with residual gases can be decreased by one order ofmagnitude. A numerical calculation also showed that∗(a) e− /e+ accumulation(b) e− /e+ cooling of HCIs(c) Extraction of cold HCIs
Fig. 1. Procedure of HCI cooling scheme with electron andpositron plasmas.

the probability of HCI loss due to recombination withelectrons is negligibly small in our scheme.8)
References
1) Y. Yamazaki ed.: Production of Ultra Slow HighlyCharged Ions, RIKEN Rev., No. 31 (2000).
2) Y. Kanai et al.: Physica Scr. T 92, 467 (2001).
3) W. Quint et al.: Hyperfine Interact. 132, 457 (2001).
4) N. Oshima et al.: Nucl. Instrum. Methods Phys. Res. B
205, 178 (2003).
5) N. Oshima et al.: J. Phys. Conference Series 2, 127(2004).
6) J. Bernard et al.: Nucl. Instrum. Methods Phys. Res. A
532, 224 (2004).
7) N. Oshima et al.: Phys. Rev. Lett. 93, 15001-1 (2004).
8) N. Oshima et al.: Nucl. Instrum. Methods Phys. Res. B(to be published).

Department of Physics, University of Tokyo

95

RIKEN Accel. Prog. Rep. 38 (2005)

Confinement of nonneutral plasma in superconducting quadrupole
magnet for antihydrogen synthesis
A. Mohri, Y. Kanai, Y. Nakai, and Y. Yamazaki
Cold antihydrogen atoms (H̄’s) have been produced
at CERN. They were synthesized from positrons (e+ ’s)
and antiprotons (p̄’s) in a nested trap that consistedof three separate Penning traps. Charged particles
of both polarities can be stored and manipulated in
the nested trap with a uniform magnetic ﬁeld, but H̄’s
synthesized in the trap cannot be trapped because of
the lack of magnetic ﬁeld gradient. For high-precision
spectropy of H̄’s and accurate determination of themagnetic moment of p̄’s to test the CPT symmetry,it is essential to conﬁne H̄’s and to extract H̄ beams
out of the trapping region.
A new scheme of cold H̄ synthesis with a recombination trap consisting of a magnetic cusp and an electrostatic quadrupole (MCEO)1) is experimentally being
studied using a superconducting quadrupole magnet,
which can generate the magnetic ﬁeld strength necessary for synchrotron radiation cooling of e+ ’s and aﬁeld gradient that is suﬃciently strong to control the
motion of H̄’s. A nonneutral e+ plasma conﬁned in
MCEO induces the electric ﬁeld. When p̄’s are guided
into the central region, they are trapped in the induced
electric ﬁeld and mixed with the positrons. These twokinds of particle are expected to recombine and formH̄’s. In a magnetic ﬁeld, H̄’s are split into four hyperﬁne states. H̄’s in the low-ﬁeld seeking states are decelerated while going to a higher magnetic ﬁeld, but thosehaving suﬃcient energy to overcome the magnetic potential barrier can be focused at a location apart fromthe cusp center. This scheme allows the extraction ofan almost 100% polarized H̄ beam of considerable intensity.
A magnet with a bore of 16 cm radius generates aﬁeld strength of 3.5 T and a gradient of 35 T/m at
maximum. Here, the ﬁeld conﬁguration enables theextraction of a focused spin-polarized beam of H̄’s in
the ground state. Figure 1 shows magnetic ﬁeld lines

in a vacuum tube and also the equipotential surfacesof an electric octupole produced with electrodes.
Experiments using this MCEO trap were ﬁrst performed on nonneutral electron conﬁnement in a warm
bore to establish the control method of particle accumulation in the trap and also to elucidate the dynamics
of electrons trapped in a high magnetic ﬁeld, such as
diﬀusion across the magnetic ﬁeld and cooling by synchrotron radiation. Figure 2 illustrates the setting ofcomponents inside the vacuum tube. Pulsed electrons
are injected with the electron gun into the MCEO trap
and the total number of trapped electrons is measured
by dumping them to the Faraday cup. The numberof trapped electrons does not change for a time longer
than 100 s. This means that the electron plasma is
conﬁned in the trap without touching the surrounding
walls for a long time2) . The electric ﬁeld needed to trap
positively charged ions (or p̄’s) depends on the spatial
density distribution of the trapped electrons (or e+ ’s).
Experiments to ﬁnd the electron density distribution
are now under way.

Fig. 2. MCEO trap using a superconducting quadrupole
magnet. An electron gun, electrodes for the octupole
and a Faraday cup with fluorescent screen are housedin the vacuum tube.

References
1) A. Mohri and Y. Yamazaki: Europhys. Lett. 63, 207(2002).
2) A. Mohri, Y. Kanai, Y. Nakai, and Y. Yamazaki:
Proc. 31st European Physical Society Conf. on Plasma
Physics, London, UK, 2004-7 (European Physical Society, 2004), P4-225.

Fig. 1. Field lines of the magnetic cusp and equipotential
surfaces of the electric octupole used for MCEO.

96

RIKEN Accel. Prog. Rep. 38 (2005)

Precision spectroscopy of Zeeman splittings of 9 Be+ 2 2 S1/2 hyperfine
structure levels (III)T. Nakamura,∗1 M. Wada, K. Okada,∗2 I. Katayama,∗1 S. Ohtani,∗3 and H. A. Schuessler∗4
We have been conducting precision measurements ofthe ground-state hyperﬁne structure (hfs) of trapped
9
Be+ ions in a strong magnetic ﬁeld using a combined
trap1) and laser-microwave multiple resonance spectroscopy methods.2) The main purpose of our projectis to study the nuclear structure of unstable nuclei
through the Bohr-Weisskopf eﬀect, which is deduced
from a comparison of the hfs constant A, which isnormalized by the nuclear gI -factor, among the isotopes. The hfs constant A and the nuclear gI -factor inunits of the electronic gJ -factor were determined fromtwo pairs of transition frequencies, the nuclear spin-ﬂip
transitions νn and the electron spin-ﬂip transitions νe ,at diﬀerent optical pumping conditions, σ+ and σ− .
We achieved high accuracies of 10−9 and 10−7 forthe measurement of A and gI /gJ , respectively, at theexternal magnetic ﬁeld B0 = 0.47 T.2) Although thepresent accuracy is suﬃcient for our primary purpose,
we have worked on improving the accuracies. Our measurement values are slightly inconsistent with a previously reported values by the NIST group3) at diﬀerent
strengths of the magnetic ﬁeld. Fortson and Fletcher
proposed theories on a possible quadratic dependenceof the hfs constant A and the nuclear gI -factor on thestrength of the external magnetic ﬁeld.4,5) Since ourexperimental method allows the measurement of theconstant at an arbitrary strength of the magnetic ﬁeld,
the dependence on the magnetic ﬁeld can be determined with a high accuracy.
In our previous resonance detection scheme, a driftof the magnetic ﬁeld strength had a signiﬁcant eﬀect
on the obtained accuracies. Therefore, we modiﬁed themeasurement sequence to measure the nuclear spin-ﬂip
transition and the electron spin-ﬂip transition, simultaneously. The coherent time of each measurement cycle was also increased to decrease the line width of theresonance curve. We measured using the new scheme
two pairs of transition frequencies at the B0 = 0.58 T
as shown in Fig. 1. From these frequencies, we obtained new values of A = −625 008 836.07(11) Hz andgI /gJ = 2.134 780 406(35) × 10−4 . All previously reported values including our recently obtained values
are plotted as the function of B0 in Fig. 2. It should bepointed that the NIST values (a) were obtained fromfrequencies at diﬀerent ﬁeld strengths, B0 = 0.68 T
∗1
∗2
∗3
∗4

Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Department of Physics, Sophia University
Institute for Laser Science, University of Electro-Communications
Department of Physics, Texas A&M University, USA

Fig. 1. Measured two pairs of transition frequencies, nuclear spin-flip transitions νn and electron spin-flip transitions, νe for σ+ (left) and σ− (right) at B0 = 0.58 T.
The linear correlations in two graphs indicate good experimental consistency.

Fig. 2. Magnetic field dependence of the A and gI /gJ . (a)NIST values (see text), (b) our previously reported values at B0 = 0.47 T,2) and (c) our presently obtained
values at B0 = 0.58 T.

and 0.82 T for σ± , so that the values are not applicable to discussing the B0 dependence. Also our previous
measurements at B0 = 0.47 T are not suﬃciently accurate. Therefore, we now measure at diﬀerent B0 values
with high accuracies to determine the dependence ofA and gI /gJ on the strength of the magnetic ﬁeld.
References
1) T. Nakamura et al.: J. Appl. Phys. 89, 2922 (2001).
2) T. Nakamura et al.: Opt. Commun. 205, 329 (2002).
3) D. J. Wineland et al.: Adv. At. Mol. Phys. 19, 135(1983).
4) G. D. Fletcher et al.: Phys. Rev. Lett. 58, 2535 (1987).
5) N. Fortson: Phys. Rev. Lett. 59, 988 (1987).

97

RIKEN Accel. Prog. Rep. 38 (2005)

Laser-induced fluoresence spectra of alkaline-earth ion-helium
exciplexes produced in cold helium environment
Y. Fukuyama, Y. Moriwaki,∗ and Y. Matsuo
Superﬂuid He (He II) is expected to be a suitablemedium in the study of short-lived radioactive nuclei because it can instantly stop atoms and ions thatare produced in a fragmentation reaction with a highkinetic energy (∼100 MeV/u).1) In addition, various
laser spectroscopic methods can be achieved in He II
because He II is transparent in a wide wavelength region from radio frequency to vacuum ultraviolet. The
high-resolution laser spectroscopy of atoms in He II
will reveal nuclear properties such as electromagnetic
moments. However, in a cold He environment, there
are few spectroscopic studies on impurities, although
the study on impurities itself has a long history. In addition, it is known that certain atoms and ions form exciplexes with He atoms in liquid He and cold He gas.2)
To perform a laser spectroscopic study of unstable nuclei in He II, it is necessary to investigate spectroscopic
properties of atoms and ions in a cold He environment.
In this paper, we describe the laser-induced ﬂuoresence(LIF) detection of impurity ions such as Ba+ in a cold
He gas and report the ﬁrst observation of Ba+∗ -He exciplexes in the same environment at 3–30 K.3)
The experimental setup is illustrated in Fig. 1. The
experimental apparatus consisted of a cryostat chamber, an ablation laser, an excitation laser, and a detection system. The bottom part of the cryostat chamber
contained liquid He. The space above the liquid He
was ﬁlled with cold He gas. A small solid Ba sample was placed in an open quartz container, which was
ﬁxed above the liquid level, to prevent the disturbanceof direct He gas ﬂow. Barium ions were producedin the cold He gas by ablating the solid Ba sample
with the third-harmonic pulse of the Nd:YAG laser
output (355 nm, ∼10 mJ/pulse). Typically, 1010 ionswere dispersed in the cold He gas. Then, the Ba+
ions were irradiated using a pulsed dye laser (455 nm,
1 µJ/pulse). A LIF from ions and exciplexes was detected with a photomultiplier tube through a 25 cm
grating monochromator, and the signal was averaged
with a boxcar integrator and stored in a computer.
We observed LIF spectra of Ba+ in the cold He gas
by exciting Ba+ ions from the 6s 2 S1/2 ground state to
the 6p 2 P3/2 excited state (D2 excitation). The typical
spectrum observed at the temperature of 25 K and thepressure of 6700 Pa is shown in Fig. 2. The observed
spectrum was composed of a sharp line of D1 transition(6s 2 S1/2 –6p 2 P1/2 ) of Ba+ at 20262 cm−1 and a broad
ﬂuorescence band over a range of 20500–21800 cm−1 .
The broad ﬂuorescence band was observed only in thetemperature and pressure ranges of 3–30 K and 2000–
27000 Pa, respectively. This broad ﬂuorescence bandof the Ba+∗ -He exciplex was composed of four components that were assigned as transitions from diﬀerent
vibrational levels (v = 0, 1, 2 and 3) in the 6p 2 Π3/2
state to the bound free 6s 2 Σ1/2 state. We also performed ab initio calculations to determine the pair potential of the Ba+ -He system and calculated emission
spectra based on the Franck-Condon approximation.
The observed emission spectra of Ba+∗ -He exciplexes
were reasonably in good agreement with the calculated
ones.

Fig. 2. LIF spectra of Ba+ ion and Ba+∗ -He exciplex.

References
1) Y. Fukuyama et al.: RIKEN Accel. Prog. Rep. 35, 101(2002).
2) H. Günther and B. Tabbert: Z. Phys. B 98, 297 (1995).
3) Y. Fukuyama et al.: Phys. Rev. A 69, 042505 (2004).
Fig. 1. Experimental setup.
∗98

Department of Physics, Toyama University

RIKEN Accel. Prog. Rep. 38 (2005)

Long electronic spin relaxation time of Cs atoms
in superfluid helium
T. Furukawa,∗1 Y. Matsuo, A. Hatakeyama,∗2 Y. Fukuyama, T. Kobayashi, H. Izumi,∗1 Y. Arakawa,∗1
I. Wakabayashi,∗1 K. Kawai,∗1 S. Morinobu,∗1 and T. Shimoda∗1
We have been studying optical pumping of impurity atoms in superﬂuid helium (He II) with the aim ofestablishing a versatile method for determining the nuclear moments of unstable nuclei from their hyperﬁne
structure.1) The broadened absorption line spectrumof the atom in He II is very promising for pumping awide variety of atomic species. The electronic spin relaxation time of the atoms in He II is the key quantity
for successful of optical pumping. Kinoshita et al.2)
succeeded in polarizing the alkali metal atoms (Rb andCs) in He II by optical pumping, but no quantitative
measurement of the relaxation time has been carriedout to date.
We have measured for the ﬁrst time the longitudinal spin relaxation time T1 of Cs atoms in a holding
magnetic ﬁeld B0 of approximately 5 G in He II, using
the “relaxation in the dark” method.3,4) This method
is based on the fact that the laser-induced ﬂuorescence(LIF) signal observed with circularly polarized “pumping” light, tuned to the wavelength of the D1 excitation line of Cs atoms in He II, is proportional to thenumber of depolarized atoms. The LIF intensity I isdescribed as
I ∝ NCs × (1 − Pz ),∗2

Pz (τ ) = 1 −

I(τ )
,
I0

(2)

which is independent of NCs
Then, we obtained the polarization Pz (τ ) for eachdark period up to 1.4 s, and we determined the spin relaxation time T1 deduced from the polarization Pz (τ ).
Figure 1 shows the relative polarization Pz (τ )/Pz (0)as a function of τ . From a single component exponential ﬁt, the spin relaxation time of T1 = 2.56(19) s wasdetermined at the helium temperature of about 1.6 K
and a holding magnetic ﬁeld B0 of approximately 5 G.
This extraordinary long spin relaxation time is evenlonger than that in solid helium (bcc phase) of about
1–2 s.4,5) This result encourages us to take advantage of
He II as a suitable environment for trapping unstable
nuclear beams and for performing laser spectroscopy
for the measurement of nuclear moments.

(1)

where NCs is the number of Cs atoms and Pz is the electronic spin polarization of the atoms.4,5) The detailsof the method are as follows. At the beginning of themeasurement, Cs atoms were injected locally into theoptical detection region in He II by the laser sputtering technique.6) The injected Cs atoms were optically
pumped and polarized with irradiation of the pumping
laser light. After the pumping of Cs atoms, LIF was
not observed from polarized atoms. Next, the pumping laser light was switched oﬀ during the dark period
τ . The optical pumping of Cs atoms was interrupted
and Cs atoms were gradually depolarized by the perturbing ﬁeld from the surrounding helium atoms during this period. When the pumping laser light wasirradiated again after the dark period, the LIF signals
were revived. In the liquid He II, the number of injected Cs atoms in the measurement region of He II,
NCs in Eq. (1), gradually decreased due to the diﬀusion of the atoms. In order to compensate for the eﬀectof the time-variant NCs , we depolarized the Cs atoms
compulsorily by irradiating the linear polarized D1 excitation laser light immediately after the measurement∗1of I(τ ), and we measured the LIF intensity I0 , namely
the intensity from the atoms of Pz = 0. From Eq. (1),the intensity I0 was proportional only to the number of
Cs atoms NCs . We determined the polarization Pz (τ )from the ratio of these two LIF intensities, as

Fig. 1. Spin relaxation of Cs atoms in He II as function ofdark period τ .

References
1) T. Furukawa et al.: Ann. Rep. Osaka University Laboratory of Nuclear Studies 2002, 27.
2) T. Kinoshita, Y. Takahashi, and T. Yabuzaki: Phys.
Rev. B 49, 3648 (1994).
3) W. Franzen et al.: Phys. Rev. 115, 850 (1959).
4) M. Arndt et al.: Phys. Rev. Lett. 74, 1359 (1995).
5) S. Lang et al.: Phys. Rev. A 60, 3867 (1999).
6) A. Fujisaki et al.: Phys. Rev. Lett. 71, 1039 (1993).

Department of Physics, Graduate School of Science, Osaka
University
Institute of Physics, Graduate School of Arts and Sciences,
University of Tokyo

99

RIKEN Accel. Prog. Rep. 38 (2005)

Development of optical detection technique for single spin indiamond N-V center
G. Kato,∗1 T. Arai,∗1 D. Nagae,∗1 K. Shimada,∗1 M. Tsukui,∗1 H. Miyoshi,∗1 D. Kameda,∗1
S. Emori,∗1 M. Uchida,∗1 M. Kurosawa,∗2 A. Yoshimi, H. Ueno, T. Haseyama, Y. Kobayashi,
E. Yagi, K. Kawasaki,∗1 and K. Asahi∗1
The exclusively long relaxation times that areachieved for nuclear spins in solids suggest a promising nuclear spin system for quantum bits. However, torealize nuclear spin qubits, the observation and operation of a single nuclear spin are inevitably required.
A 15 N nuclear spin in a diamond N-V center would
provide such an opportunity.
The N-V center consists of a nitrogen atom substituting for a carbon atom and a nearest-neighbor vacancy as illustrated in Fig. 1 (a).1) The N-V centers areproduced in type Ib diamond by high-energy electron
irradiation and subsequent annealing. The N-V centerhas a 3 A ground state and a 3 E excited state with avery short lifetime (see Fig. 1 (b)). The notably luminous optical transition between these states2) would
provide a means of detecting a single nuclear spin in the
N-V center: After repetition of the optical excitationand de-excitation, the electronic spin state is oriented
preferentially to the population of the ms = 0 state.
Once the orientation of electronic spins is achieved,
the application of a microwave for the ESR transition
between the hyperfine-split levels leads to an intensity change in the optical transition, thus enabling ahigh-sensitivity detection of ESR (optically detected
ESR). Furthermore, by incorporating an NMR transition with ESR the polarization of nitrogen nuclear
spins is induced. We are investigating the method of
examining this nuclear polarization process by detecting β-rays from the unstable nuclei 17 N.
As the first step toward the operation of the spin ensemble, we performed an ESR experiment on type Ib
diamond. Among the nitrogen-related defect centersthat are known in the type Ib diamond, the P1 center is understood as a structure with a nitrogen atom
substituting for a carbon atom.3)

The ESR spectrum obtained for the type Ib diamond (Sumitomo HT-HP synthetic diamond) is presented in Fig. 2. The spectrum was obtained under
the condition that the applied magnetic field B0 wasparallel to the [100] direction of the diamond crystal. In terms of the hyperfine coupling (hfc) constant A, the resonance frequencies are expressed ashν = ge µB (B0 + AmI ). The hyperfine interaction between 14 N (nuclear spin I = 1) and an unbound electron gives rise to three resonance lines. From this spectrum, we obtained the hfc constant A = 3.4 ± 0.1 mT.
Because this value agrees well with the A value known
for the P1 center (A = 3.36 mT3) ), we consider thatthe obtained ESR spectrum originates from the substitutional nitrogen structure. To confirm the substitutional nitrogen structure of the P1 center, the β-NMR
method can be used. For the magnetic moment 17 N,|µ(17 N)| = (0.352 ± 0.002)µN ,4) the hfc constant iscalculated as A17 N ∼ 5.8 mT.
Until now, we have investigated the ESR spectrum
on the P1 center of a type Ib diamond sample. We havealso started producing the N-V center. Several type Ib
diamond samples were irradiated with 2 MeV electron
beams (doses from 5 × 1012 e/cm2 to 1 × 1016 e/cm2 )and annealed for 1 h at T = 1173 K and 923 K. Analyses of these samples by ESR,5) FT-IR5) and fluorescence1,2) measurements are under way. We also plan
to observe the magnetic resonance of the N-V centerby optical detection.

Fig. 2. ESR spectrum of P1 center in type Ib diamond.

References
Fig. 1. Crystalline structure (a) and energy levels and excitation scheme (b) of N-V center.
∗1
∗2

100

Department of Physics, Tokyo Institute of Technology
Department of Physics, Tokyo University of Science

1) F. T. Charnock and T. A. Kennedy: Phys. Rev. B 64,
041201 (2001).
2) A. Gruber et al.: Science 276, 2012 (1997).
3) W. V. Smith et al.: Phys. Rev. 115, 1546 (1959).
4) H. Ueno et al.: Phys. Rev. C 53, 2142 (1996).
5) A. Lenef et al.: Phys. Rev. B 53, 13427 (1996).

RIKEN Accel. Prog. Rep. 38 (2005)

Channelling studies on the lattice location of B atoms in graphite†
E. Yagi, T. Iwata,∗ T. Urai, and K. Ogiwara
Boron has ａ favourable eﬀect on graphitization ofcarbon. A number of properties of graphite are inﬂuenced by the presence of boron. For example, theboron atom is expected to act as an acceptor, when
it substitutes a carbon atom. Regarding where boron
atoms are located in a graphite crystal lattice, experimental results on the B concentration dependence oflattice parameters,1,2) a density,1) and electronic properties3,4) suggest that boron occupies a substitutionalsite. In the present study, to obtain additional direct
information on the lattice location of boron atoms,
channelling experiments are performed. There exist
0001 axial channels surrounded by C atomic rows in
the c-direction as shown in Fig. 1 by broken lines andalso {0001} planar channels between c-planes in perpendicular to the c-direction.
Specimens are highly-oriented pyrolytic graphite(HOPG) crystals doped with 0.32 at.% B. B atoms
were detected with a proton beam, utilizing a resonant nuclear reaction 11 B(p,α)αα around 0.624 MeV(the resonance width (FWHM) is about 0.3 MeV); theB atoms were detected by measuring the α-particles,
whose energy extended up to about 5 MeV.
Channelling experiments were performed at room
temperature with a 0.666 MeV proton beam for the0001 channel. Backscattered protons (C-angular proﬁles) and emitted α-particles (B-angular proﬁles) were
measured at angles of 160◦ and 150◦ , respectively, as
a function of the incident angle with respect to thec-axis. Measurement for the {0001} channel was also
tried, but it was unsuccessful, due probably to diﬃculties in preparation of the surface suitable for channelling experiments. Figure 2 shows the angular pro-

Fig. 2. The channelling angular profiles of backscattered protons and emitted α-particles obtained with a
0.666 MeV proton beam at room temperature.

ﬁles. In this case, in order to compare the C- and Bangular proﬁles for approximately the same depth region (from the surface to 1.75 µm), Al foil 13 µm thick
was placed in front of the α-particle detector as an energy absorber. Both angular proﬁles exhibit the same
dips, indicating that most of B atoms are shadowed
behind the 0001 C atomic rows. As such sites, there
are three types of sites; (1) a substitutional site, (2) acentre of a hexagon (a b -site in Fig. 1) and (3) any site
between two c-planes on the 0001 atomic row (d- andd -sites in Fig. 1). The ﬁrst two types of sites are on
the c-plane. The latter two sites (d- and d -sites) are
interstitial sites. As the measurement for the {0001}
channel was unsuccessful, it is impossible to make distinction between these two groups of sites. It is widely
accepted that the d -site is stable, whereas the b - andd-sites are unstable because of a large repulsive force
from adjacent atoms. On the other hand, from thecalculation by the molecular dynamical method, Taji,
Yokota, and Iwata found that the stable site for theinterstitial C atom is not the d -site, but a site displaced from the d -site toward the channel centre between two c-planes, i.e., the e-site in Fig. 1.5) If the
B atoms are located at either d -site or e-site, the cspacing should increase with B concentration, in contrast with the results of the X-ray diﬀraction. Hence,
it is concluded that most of B atoms are located at
substitutional sites.
References

Fig. 1. (a) The crystal structure of graphite. (b) The projection of the 0001 channel onto the plane perpendicular to the c-axis.
†∗

Condensed from the article in J. Nucl. Mater. 334, 9 (2004)
Japan Atomic Energy Research Institute1) C. E. Lowell: J. Am. Ceram. Soc. 50, 142 (1967).
2) P. Wagner and J. M. Dickinson: Carbon 8, 313 (1970).
3) D. E. Soule: Proc. 5th Conf. on Carbon, Vol.1, (Pergamon Press, New York, 1962), p.13.
4) S. Marinkovic: in Chemistry and Physics of Carbon,
Vol.19, edited by P. A. Thrower (Marcel Dekker, New
York, 1984), p.1.
5) Y. Taji, T. Yokota, and T. Iwata: J. Phys. Soc. Jpn.
55, 2676 (1986).

101

RIKEN Accel. Prog. Rep. 38 (2005)µSR study on magnetism of organic Mott insulator having
two-dimensional triangular lattice
S. Ohira, Y. Shimizu∗1,∗2 , K. Kanoda∗2 and G. Saito∗1
κ-(BEDT-TTF)2 X is a strongly correlated electron
system having a 2D layer structure of BEDT-TTF(ET) molecules, where X is a monovalent anion. They
have been known to exhibit a superconducting (SC) or
antiferromagnetic (AFM) phase as the ground state.1)
However, it has been suggested that one of the Mott
insulators, κ-(ET)2 Cu2 (CN)3 , shows no long-range
magnetic ordering.2,3) The ET dimers form a nearly
isotropic triangular lattice in this salt. The groundstate of the 2D triangular lattice system with spin-1/2
is theoretically suggested to be a spin liquid state,4)
while it is experimentally still unclear since the existing materials are few. Because the salt also shows theSC transition under moderate hydrostatic pressures,2)
this can be a candidate to have the spin liquid groundstate which neighbors the SC phase. We carried out
a ZF-µSR measurement on this salt down to 1.5 K toclarify its magnetic property.
The experiment was carried out at the RIKEN-RAL
Muon Facility in the Rutherford Appleton Laboratory(RAL) down to 1.5 K. 200 mg of the polycrystalline
sample was packed into a silver foil and ﬁxed onto thesample holder.
Muon spin relaxation due to nuclear dipole ﬁelds
was observed down to 1.5 K (Fig. 1). It is noted thatthe relaxation is slightly enhanced at 1.5 K. The time2
spectra are well ﬁtted with A(t) = Ae−λt e−(σt) , where
λ is the muon spin relaxation rate for describing the
dynamically ﬂuctuating internal ﬁeld, and σ is the dis-Fig. 2. Temperature dependences of (a) the relaxation rate
λ and (b) the distribution width of the internal field at
the muon site σ.

tribution width of the internal ﬁeld at the muon site.
The ﬁtting results below 100 K are shown in Fig. 2.
λ shows a slight increase below ∼4 K with decreasing
temperature. Because the enhancement of the relaxation is quite small, this behavior diﬀers from the critical slow-down eﬀect associated with the magnetic transition. In our previous experiment, no magnetic transitions were observed from 20 mK to 1.5 K. Our µSR
studies strongly suggest the possibility of the quantum
spin liquid ground state neighboring the SC phase inthis salt.
The anomaly in the relaxation rate at around 4 K
is also observed in the 1 H NMR measurement.3) The
proton spin-lattice relaxation rate, T1−1 , starts to increase below 4 K and exhibits a broad peak at ∼1 K.
It is expected that some spin dynamics changes below
around 4 K. More detailed studies at low temperatures
are currently in progress.
References

Fig. 1. ZF-µSR time spectra of κ-(ET)2 Cu2 (CN)3 .

∗1
∗2

102

Division of Chemistry, Kyoto University
Department of Applied Physics, University of Tokyo

1) K. Kanoda et al.: Physica C 282–287, 299 (1997); K.
Kanoda, Hyperfine Interact. 104, 235 (1997).
2) T. Komatsu et al.: J. Phys. Soc. Jpn. 65, 1340 (1996).
3) Y. Shimizu et al.: Phys. Rev. Lett. 91, 107001 (2003).
4) L. Capriotti et al.: Phys. Rev. Lett. 82, 3899 (1999).

RIKEN Accel. Prog. Rep. 38 (2005)

Plans for superheavy-element chemistry in RIKEN: Development ofgas-jet transport system coupled to GARIS
H. Haba, D. Kaji, K. Morimoto, S. Motomura, S. Enomoto, and K. Morita
Recently, the investigation of the chemical properties of superheavy elements (SHEs) with atomic number Z ≥ 104 is one of the most interesting and challenging subjects in nuclear and radiochemistry. The increasingly strong relativistic eﬀect on the valence electrons of SHE atoms is expected to induce deviations inchemical properties from the periodicity based on theirlighter homologues in the periodic table. The production rates of the SHE nuclides are extremely low, i.e.,
atoms per minute for elements 104 and 105, down toatoms per day for elements 106 to 108, and their halflives are less than ∼1 min. This situation forces us toperform rapid and eﬀective chemical experiments withsingle atoms.
The experimental studies on the chemical propertiesof SHEs have been performed for elements 104 to 108,and very recently for element 112.1) To perform rapid
and eﬀective chemical separations of SHE, the gas-jet
transport technique has been commonly used to deliver
SHE atoms from the target chamber to various chemical separation apparatuses. Nuclear reaction products
recoiling out of the target are stopped in the recoilchamber ﬁlled with helium gas. After being stopped
in the gas, the reaction products become attached tothe aerosol particles such as potassium chloride andcarbon. The gas and activity-laden aerosol particles
are sucked through a capillary tube to a distant site
by applying a vacuum to the downstream end of thecapillary tube, where the aerosol particles are collected
on a foil or ﬁlter and can be made rapidly available forchemical separation.
The SHE atoms are produced at extremely low rates
among much larger amounts of background activities

which hinders the detection of decays of the SHE nuclides of interest. In addition, recently available highintensity beams of more than 1 pµA give rise to a serious problem in that the plasma formed by the beams
signiﬁcantly decreases the gas-jet transport eﬃciency.
For these reasons, there is a recognized need for physical preseparation of the SHE atoms before chemical
separation. It has been proposed that the kinetic separator for nuclear physics research on SHEs could becoupled to the chemistry system with the aid of thegas-jet transport technique. Since 2002, related workshops have been held to discuss the merits and design of such devices.a) This method enables one to
study the chemical properties of various compounds
by directly introducing complexing reagents into thechamber, since one no longer has to deal with theharsh ionizing conditions caused by the beam. Furthermore, background activities that cannot be eﬀectively separated from SHEs, such as that from Po or
Rn isotopes, are largely removed by the recoil separator. The ﬁrst experiment with the recoil transfer
chamber coupled to the Berkeley Gas-ﬁlled Separator(BGS) was a great success.2) The isotope of 257 Rf physically separated from the large background caused by
β-particles was unambiguously identiﬁed with a liquid scintillator after a liquid-liquid solvent extraction
into 0.25 M dibutyl-phosphoric acid in toluene from
6 M HNO3 with SISAK. At Gesellschaft für Schwerionenforschung (GSI), the components of the former
HElium Charge-exchange Kaleidoscope (HECK) separator are being used to set up a dedicated separator
for chemistry experiments.a)
In the RIKEN Linear Accelerator Facility, a gas-

Fig. 1. Overview of gas-jet transport system coupled to GARIS.
a)

3rd Workshop on Recoil Separator for Superheavy Element
Chemistry, GSI, Darmstadt, Germany, 2004-8 (http://wwww2k.gsi.de/tasca04/).

103

ﬁlled recoil separator, GARIS, is now in operation to
search for the heaviest SHE nuclides. Recently, theisotopes of 271 Ds, 272 Rg, and 278 112 found at GSI
were conﬁrmed by better statistics and new spectroscopic information,3,4) and a new isotope of element
113, 278 113, was successfully synthesized.5) We plan
to initiate SHE chemistry in RIKEN using GARIS.
An overview of the gas-jet transport system coupled
to GARIS is shown in Fig. 1. In this work, the gasjet chamber was installed in the focal plane of GARIS(see Fig. 2). The gas-jet chamber at an inner pressureof ∼100 kPa should be isolated from the beam duct of
GARIS at ∼100 Pa by a very thin Mylar-vacuum window. For this purpose, we use a stainless-steel honeycomb grid with 93% transparency and having 0.5 mm
thickness and 60 mm diameter, which can support the
Mylar foil to 2.5 µm thickness. As shown in Fig. 1, therecoiling SHE nuclides preseparated with GARIS are
passed through the Mylar window and are stopped ina volume of helium gas. The helium gas, often seededwith aerosol particles, is introduced into the chamber through the four inlets (4 mm i.d.) and is suckedout through a Teﬂon capillary tube (1.6 mm i.d.) intoa chemistry apparatus. The entire inner wall of thechamber is fabricated from chemically inert Teﬂon or
Dyﬂon to enable the direct introduction of chemical
reagents into the chamber. The volume of the chamberis optimized for the range of product nuclei of interest
with spacers of 20, 40, and 60 mm thicknesses.
We have also developed a rotating wheel system forthe measurement of α and spontaneous ﬁssion decaysof the SHE nuclides. This is a compact version of the
Measurement system for the Alpha-particle and spontaneous ﬁssioN events ON-line (MANON) developed
in JAERI.6) The product nuclei transported by thegas-jet system are deposited on Mylar foils of ∼1 µm
thickness and 20 mm diameter placed at the peripheryof a 40-position stainless steel wheel with a 210 mmdiameter. The wheel is stepped at desired intervals toposition the foils between six pairs of Si PIN photodiodes (Hamamatsu S3204-09) for α-particle detection.
Each detector has an active area of 18 × 18 mm2 and a
40% counting eﬃciency for α-particles. The α-particle
energy resolution is approximately 30 keV FWHM. All
events are registered in an event-by-event mode.
We will appraise the performance of the present gasjet system using the Po and Fr isotopes produced in
the 40 Ar-induced reactions on nat Dy and 169 Tm, respectively. The gas-jet eﬃciency will be systematicallymeasured with the rotating wheel system by varying
the experimental conditions such as the helium ﬂow
rate, pressure and volume of the chamber, thickness
of Mylar vacuum window, and aerosol material. Using the GARIS + gas-jet transport system, we intend
to study the chemical properties of the heaviest SHEs
such as Sg, Hs, and element 112. For this purpose,experiments to measure the excitation functions forthe 232 Th(40 Ar,α3n)265 Sg, 232 Th(40 Ar,3n)269 Hs, and238
U(48 Ca,3n)283 112 reactions are planned in the near
future.
References

Fig. 2. A picture of gas-jet chamber coupled to GARIS.

1041) M. Schädel: The Chemistry of Superheavy Elements(Kluwer Academic Publishers, Dordrecht, 2003).
2) J. P. Omtvedt et al.: J. Nucl. Radiochem. Sci. 3, 121(2002).
3) K. Morita et al.: J. Phys. Soc. Jpn. 73, 1738 (2004).
4) K. Morita et al.: Eur. Phys. J. A 21, 257 (2004).
5) K. Morita et al.: J. Phys. Soc. Jpn. 73, 2593 (2004).
6) H. Haba et al.: Radiochim. Acta 89, 733 (2001).

RIKEN Accel. Prog. Rep. 38 (2005)

Radioactive tracers produced at RIKEN accelerator researchfacility and future RI beam factory
H. Haba and S. Enomoto
Due to its high sensitivity, the radioactive tracer
technique has been successfully applied for investigations of the behavior of elements in the ﬁelds ofchemistry, biology, medicine, engineering, and environmental sciences. Since the discovery of the multitracer technique at RIKEN in 1991,1) we have produced multitracers and conducted application studies in collaboration with many researchers in various
ﬁelds.2) Recently, a new multitracer production system, which consists of a gas-jet-coupled multitarget
system for short-lived radioactive tracers and a gasand water-cooled target system for intense beam irradiations, has been installed at the K = 540 MeV
RIKEN Ring Cyclotron (RRC).3) Single radioactive
tracers such as 48 V, 67 Cu, and 206 Bi produced using the K = 70 MeV AVF Cyclotron have also been
available. The Radioactive Isotope (RI) beam facility, called the RI Beam Factory (RIBF), is now underconstruction at RIKEN. The world’s most intense RI
beams over the entire range of atomic masses up tothat of uranium are expected to open new frontiersin nuclear and radiochemistry as next-generation producers of radioactive tracers. In this paper, we brieﬂyreview the present status and prospects of the production of unique radioactive tracers at the RIKEN Accelerator Research Facility (RARF) and at the future
RIBF.
By using the falling ball system,1) radionuclides ofa large number of elements were simultaneously produced from metallic targets such as Ti, Fe, Cu, Ge,
Ag, and Au irradiated with a 135 MeV nucl.−1 14 N (or12C, 16 O) beam from RRC. After the irradiation, theseradionuclides were chemically separated from the target material,1,4–6) and then the carrier-free and saltfree multitracer solution was applied to various experiments with the aid of γ-ray spectrometry with
Ge detectors. Since the ﬁrst production of a multitracer in 1991, the beam intensity of RRC has been
increased up to approximately 1 particle µA (pµA) for
the 135 MeV nucl.−1 14 N beam, which is one order ofmagnitude higher than the acceptable intensity for thefalling ball system. This forced us to develop an eﬃcient target-cooled system and to place heavy shields
surrounding the target chamber. In addition, technical developments for the preparations of radioactive
tracers with short half-lives ( 1 h) and of elements
lost during chemical separation were strongly desired.
Thus, we have developed a new multitracer production
system on the E3b beam line of RRC as an alternative
to the falling ball system. A schematic of this system is shown in Fig. 1. It consists of a gas-jet-coupledmultitarget chamber (1st chamber) and a simple gas-

Fig. 1. Schematic of the new multitracer production systeminstalled on the E3b beam line of the K = 540 MeV
RIKEN Ring Cyclotron.

and water-cooled target chamber (2nd chamber). The
beams from RRC are collimated to a 7 mm diameterwith a 4-sector Ta slit. Then, the beam passes througha HAVAR vacuum window of 6 µm thickness and enters 30 multitarget of approximately 1 µm thickness
with 10 mm spacings in the ﬁrst chamber. The number and spacing of the targets are variable dependingon the ranges of product nuclei recoiling out of the target. The recoiling multitracers are stopped in He gas,
attached to aerosols such as KCl and C, and are continuously transported through a Teﬂon capillary (2.0 mm
i.d., 10 m long) to a chemistry laboratory just beneaththe E3 irradiation room, where the multitracers can becollected on a glass ﬁlter. In the second chamber, thebeam enters the thick metallic targets such as Ti, Ag,
and Au, which are each approximately 200 µm in thickness, and ﬁnally enters a water-cooled carbon beam
stopper. After the irradiation, the long-lived multitracers were chemically separated with the aid of almost the same procedure as applied previously.1,4–6)
The advantages of the present system are as follows.
(1) The multitracers are separated from the target material without chemical separation and transported tothe chemistry room within a few seconds. Thus, radionuclides with short half-lives of less than 1 minuteare available for experiments. (2) The targets of almost
all elements can be prepared by electrodeposition or
vacuum-evaporation techniques. The composition of
the radionuclides in the multitracer can be optimized
by changing the target material and its array. (3) The

105

Table 1. Examples of the single radioactive tracers produced using the RIKEN K = 70 MeV AVF Cyclotron.
Nuclide Half-life (d) Target
Reaction
Decay mode
γ-ray energy (intensity)
7
7
Be
53.29
LiF
Li(p,n)EC
477.6 (10.5)
48
48
V
15.9735
Ti
Ti(p,n)EC, β +
983.5 (100), 1312.1 (97.5)
54
54
Mn
312.3
Cr
Cr(p,n)EC, β +
834.8 (100)65
65
Zn
244.26Cu
Cu(p,n)EC, β +
1115.5 (50.6)
67
70
Cu
2.576
ZnO§
Zn(p,α)β−93.3 (16.1), 184.6 (48.7)
85
85
Sr
64.84
RbCl
Rb(p,n)EC, β +
514.0 (95.7)
88
88
Y
106.65SrCO3
Sr(p,n)β+898.0 (93.7), 1836.1 (99.2)
89
89
Zr
3.267
Y
Y(p,n)
β+909.1 (99.9)
92m
92
Nb
10.15
Zr
Zr(p,n)EC, β +
934.4 (99.1)
95m
95
Tc
61
Mo§
Mo(p,n)EC, β +
204.1 (63.2), 582.1 (29.9)
109
109
Cd
462.6
Ag
Ag(p,n)EC
88 (3.61)
175
175
Hf
70
Lu
Lu(p,n)EC
343.4 (84)
177
177
Ta
2.357
Hf
Hf(p,n)EC, β +
112.9 (7.2)
203
203
Pb
2.161
Tl2 O3Tl(p,n)EC
279.2 (80.8)
206
206
Bi
6.243
PbO
Pb(p,n)EC, β +
881.0 (66.2), 803.1 (98.9)§
The isotope enrichments of 70 Zn and 95 Mo are 99.5% and 96.8%, respectively.

radionuclides of interest are readily concentrated by using a gas-jet coupled liquid chromatography apparatus
based on ion exchange or solvent extraction. (4) The
targets are continuously cooled with He gas and water
during the irradiation. A beam intensity of ∼1 pµA is
acceptable, though the maximum for the falling ballsystem was approximately 0.1 pµA due to the irradiation in a vacuum chamber. Recently, the performanceof the gas-jet system was investigated with 50 radionuclides of 18 elements produced in the 135 MeV nucl.−1
14
N induced reaction on nat Cu.3)
Although the multitracers produced from the Ti,
Ag, and Au targets have been commonly used, it isquite diﬃcult to identify γ-ray peaks for certain elements such as Cu, Nb, Cd, and Ta depending on
decay properties such as half-lives and γ-ray energies
and on chemical separation. In addition, after successful screening experiments with the multitracers,
researchers often hope to focus on certain elements
and use their single tracers to increase detection sensitivities. Thus, we have started to provide single radioactive tracers produced by simple reactions such as(p,n) and (p,α) using a proton beam derived from the
RIKEN K = 70 MeV AVF Cyclotron. The target nuclei of suitable chemical forms were irradiated with a
He- and water-cooled target chamber. The 15 single
tracers now available at RARF are listed in Table 1
together with their half-lives, target materials, nuclear
reactions, decay modes, and major γ-ray energies andintensities.7) Among them, all tracers except for 54 Mn
and 109 Cd are commercially unavailable in Japan atpresent.
In recent years the advent of RI beams has opened
up a number of fascinating new ﬁelds. To further develop the new ﬁelds of science, the RIBF is under construction at RIKEN.8,9) This system consists of threering cyclotrons, K = 570 MeV ﬁxed frequency Ring
Cyclotron (fRC), 980 MeV Intermediate stage Ring
Cyclotron (IRC), and 2500 MeV Superconducting Ring
Cyclotron (SRC), and will boost the energies of theoutput beams from the existing RRC up to 440 MeV
nucl.−1 for light ions and 350 MeV nucl.−1 for heavy106

ions up to 238 U. These energetic heavy-ion beams areconverted into RI beams via projectile fragmentation
or in-ﬂight ﬁssion of 238 U by the superconducting isotope separator, BigRIPS. Thus, RIBF can derive 3000
kinds of RI beams with the world’s highest intensity.
The beam intensities for radioisotopes near the stableline, which have relatively long half-lives ( 1 min) andare practically available for radioactive tracer studies
and for radiopharmaceutical diagnosis and therapy, areover 1010 atoms s−1 .10) We can catch the RI beams
directly with suitable materials such as water, acids,
physiological saline, and radiopharmaceuticals. We
can select a radionuclide of interest with suitable decay properties for its application. Since they are massseparated from other fragment isotopes, no chemical
separations may be required for preparations of tracer
solutions. These tracer solutions should be inﬁnitely
pure and carrier free compared with those producedby conventional cyclotrons or reactors with the aid ofchemical separation. As examples, RIBF can generate
the isotopes of 28 Mg and 67 Cu, which are not readily available at present, with intensities of 2.1 × 109
and 4.6 × 1010 atoms s−1 , respectively.10) These resultin 1.2 GBq for 28 Mg and 11 GBq for 67 Cu after oneday irradiation. Thus, the RI beams derived from thefuture RIBF are expected to open new frontiers in nuclear and radiochemistry as next-generation producersof radioactive tracers.
References
1) S. Ambe et al.: Chem. Lett. 1991, 149.
2) Y. Yano and S. Enomoto: RIKEN Rev., No.35 (2001).
3) H. Haba et al.: RIKEN Accel. Prog. Rep. 37, 132(2003).
4) S. Ambe: RIKEN Rev., No.13, 3 (1996).
5) S. Ambe et al.: Anal. Sci. 7, Suppl., 317 (1991).
6) S. Ambe et al.: Radiochim. Acta 89, 63 (2001).
7) R. B. Firestone and V. S. Shirley: Table of Isotopes,
8th ed. (John Wiley & Sons, New York, 1996).
8) T. Kubo: Nucl. Instrum Methods Phys. Res. B 204,
97 (2003).
9) I. Tanihata: Nucl. Phys. A 734, 271 (2004).
10) T. Suda: private communication.

RIKEN Accel. Prog. Rep. 38 (2005)

Extraction behavior of Zr and Hf into TBP from hydrochloric acid:
Development of TBP resin for reversed-phase extraction
chromatography of element 104, rutherfordium
H. Haba, K. Tsukada,∗ K. Akiyama,∗ M. Asai,∗ A. Toyoshima,∗ Y. Ishii,∗ S. Enomoto, and Y. Nagame∗The extraction behavior of the ﬁrst transactinide
element, rutherfordium (Rf), into tributylphosphate(TBP) has been investigated together with its lightergroup-4 homologues Zr and Hf and the actinide
pseudo-homologues Th(IV) and Pu(IV).1) The extraction of Rf into TBP is considered to proceed according
to the following two reactions.
M(OH)x Cl4−x + xHCl ←→ MCl4 + xH2 O(1)

MCl4 + yTBP (aq.) ←→ MCl4 · yTBP (org.)(2)

Thus, from the extraction behavior of Rf into TBP,
we can expect to obtain information, such as chloride complexation and hydrolysis, and the stability of
TBP complexes. Czerwinski et al.2) ﬁrst examined theextraction behavior of Zr, Hf, Th, Pu, and Rf into
0.25 M TBP in benzene in 8–12 M HCl. Their results showed that the extractability of these elements
increases or remains high as a function of HCl concentration and that the extractability decreases in theorder of Zr > Rf > Hf. Kacher et al.3) performedsome additional extractions of Rf into TBP/benzene
using Ti, Zr, and Hf, and revised the extraction sequence by Czerwinski et al.2) as Zr > Hf > Rf > Ti at
about 8 M HCl. On the other hand, a reversed-phase
chromatographic separation of Rf, Zr, and Hf at 8 M
HCl was performed by Günther et al.4) using microcolumns containing TBP on an inert support, and theorder of Zr > Rf > Hf was obtained. Recently, we
have investigated the adsorption behavior of Rf, Zr,
and Hf on a strongly basic anion-exchange resin from
4.0–11.5 M HCl using an automated ion-exchange separation apparatus coupled with a detection system foralpha spectroscopy (AIDA).5) Using AIDA, we plan toperform a reversed-phase extraction chromatographyof Rf in the TBP-HCl system to clarify the conﬂicting
results mentioned above.3,4) As the ﬁrst step, we developed a TBP resin for microcolumns of AIDA (1.6 mm
i.d. × 7.0 mm or 1.0 mm i.d. × 3.5 mm) and investigated its performance by the batch method using radiotracers 89 Zr and 175 Hf.
The carrier-free radiotracers of 89 Zr and 175 Hf
were produced in the 89 Y(p,n) and 175 Lu(p,n) reactions, respectively, using a 14-MeV proton beamfrom the RIKEN K70 MeV AVF Cyclotron. A support material used was MCI GEL CHP20Y, supplied by Mitsubishi Chemical Corporation, a styrenedivinylbenzen copolymer with a particle size of about∗

Advanced Science Research Center, Japan Atomic Energy
Research Institute

30 µm. The resin was washed several times alternatelyby the batch method with methanol and acetone, andwas dried at 110◦ C in a vacuum oven. The resin in a
beaker was suspended in methanol with stirring, and
TBP was dropped. After stirring hermetically for 12 h,methanol was evaporated to dryness at room temperature, and dried to a constant weight at 110◦ C. The
TBP weight percentages (wt.%) were 5–60%. The
TBP resin (5–30 mg) and 3 mL of 6.0–11.9 M HCl containing 50 µL of 89 Zr and 175 Hf tracer solution in 6 M
HCl were placed in a polypropylene tube and shaken
for 4 h at 20◦ C. After centrifugation, 1 mL of the aqueous phase was pipetted into a polyethylene tube andsubjected to γ-ray spectrometry using a Ge detector.
As a standard sample, 50 µL of the tracer solution was
diluted to 1 mL with 6.0 M HCl in another polyethylene tube. The distribution coeﬃcient Kd in mL g−1
was obtained using Kd = Ar Vs /As Wr , where Ar andAs are the radioactivities in the resin and the solution,
respectively, and Vs is the volume of the acid solution
and Wr is the mass of the dry resin.
In Fig. 1 (a), the variations of the Kd values ofFig. 1. Variations of (a) Kd values of 89 Zr and 175 Hf
on 26-wt.% TBP resin and of (b) the separation factor Kd (Zr)/Kd (Hf) as a function of HCl concentration, compared with those on the anion-exchange resin
CA08Y.5)107

89

Zr and 175 Hf on the 26-wt.% TBP resin are indicated by closed squares and closed circles, respectively,
as a function of HCl concentration ([HCl]) comparedwith those on the anion-exchange resin CA08Y.5) As
shown in Fig. 1, the Kd values of Zr on the TBP resin
are larger than those of Hf, and both increase steeply
up to 3 × 105 mL g−1 with [HCl]. This range of theKd values fully covers that of CA08Y, with which theanion-exchange separation of Rf was successfully performed using AIDA.5) On the other hand, the separation factors Kd (Zr)/Kd (Hf) are indicated in Fig. 1 (b)by closed squares. The Kd (Zr)/Kd (Hf) values decrease
with [HCl] from ∼10 at 7.0 M, and become constant at
about 11.0 M. A diﬀerence in the extractability among
the group-4 elements may be clearly found at ∼7 M,
where a good separation between Zr and Hf is achieved.
In separate experiments, we also investigated the variations of Kd values as a function of wt.% of the resin.
The Kd values increase smoothly with wt.% in thestudied wt.% range of 5–60%. We can adjust the extractability of the TBP resin by varying its wt.%.
Using the TBP resin developed in the present work,
we will conduct the on-line extraction chromatography108

of 261 Rf, 85 Zr, and 169 Hf at the JAERI Tandem Facility. In addition, the detailed structural data of Zr and
Hf in HCl and in TBP are essential for discussing theexperimental results of Rf and performing the theoretical molecular orbital calculations. We will measure
the extended X-ray absorption ﬁne structure (EXAFS)
spectra of the Zr and Hf complexes at the High Energy Accelerator Research Organization Photon Factory. Furthermore, relativistic molecular orbital calculations will be performed for chloride and TBP complexes of Rf, Zr, and Hf to discuss chloride complexation and the stability of TBP complexes in detail andto obtain information on the electronic structure of Rfsuch as the inﬂuences of relativistic eﬀects.
References
1) M. Schädel: The Chemistry of Superheavy Elements(Kluwer Academic Publishers, Dordrecht, 2003).
2) K. R. Czerwinski et al.: Radiochim. Acta 64, 29 (1994).
3) C. D. Kacher et al.: Radiochim. Acta 75, 127 (1996).
4) R. Günther et al.: Radiochim. Acta 80, 121 (1998).
5) H. Haba et al.: J. Nucl. Radiochem. Sci. 3, 143 (2002).

RIKEN Accel. Prog. Rep. 38 (2005)

Development of on-line solvent extraction system forheavy actinide elements
Y. Kitamoto,∗ D. Saika,∗ K. Matsuo,∗ Y. Tani,∗ H. Hasegawa,∗ W. Sato,∗ N. Takahashi,∗ T. Yoshimura,∗
H. Haba, S. Enomoto, and A. Shinohara∗
It is theoretically expected that the chemical properties of the heaviest elements such as heavy actinide
and trans- actinide elements deviate from the periodicity exhibited among their lighter homologues due tothe inﬂuence of the relativistic eﬀect. However, a limited number of atoms (one or a few typically) are available at a time because of their short lifetime and small
production cross section in heavy-ion-induced nuclear
reactions. In the experimental conditions, rapid chemical operations and measurements need to be performed
many times. Therefore, we are developing an automated rapid chemical apparatus for the chemical studies of the heavy actinide elements. The apparatus using solvent extraction and the anion-exchange method
is schematically shown in Fig. 1. In this work, thedistribution of lanthanide elements in the solvent extraction by thenoyltriﬂuoroacetone (TTA) was studied
with the apparatus as a simulation for actinide elements.
A batch experiment was performed with radiotracersof 153 Gd, 169 Yb and 170 Tm. The tracers were dissolvedin a 0.5 M acetic buﬀer (pH 4.46) as an aqueous phase.
TTA was dissolved in toluene and adjusted to 0.01–
0.1 M (organic phase). A one milliliter portion of eachsolution was mixed and shaken for 20 minutes. Aftercentrifugation, 0.8 mL aliquots of both phases were collected separately and subjected to γ-ray spectroscopy
with a Ge detector.
An on-line experiment was performed using the E3bcourse of the RIKEN Accelerator Research Facility.
The nat Pb targets (2 µm in thickness×30 sheets) were
irradiated with 135 MeV/nucleon 14 N ions with an intensity of 50 pnA on average. The nuclides producedby the nat Pb (14 N, X) nuclear reactions were transported through a capillary tube with a gas jet to the
hot laboratory within a few seconds.
They were collected on a dissolver unit and dissolvedin a mixture of methanol and nitric acid at a volume ratio of 90 to 10%. They were then fed into ananion-exchange column (MCI GEL CA08Y, Mitsubishi
Chemical Corporation, 2.0 mm i.d. × 60 mm). Lanthanide elements were held on the column, while theircoproducts such as transition elements were eluted. An
acetic buﬀer solution (0.5 M, pH 4.46) was fed into thecolumn in order to elute the lanthanide elements. The
eluent was mixed with a 0.024–0.046 M TTA-toluene
solution with a static mixer and stirred ultrasonicallyfor 2 minutes. After centrifugation, 0.8 mL aliquots ofboth phases were collected separately and subjectedto γ-ray spectroscopy with a Ge detector. The yieldsof lanthanide elements for the gas-jet transportation,
dissolution and anion exchange were 10%, 20–50% and20–30%, respectively. Almost all of transition elements
were removed by the anion exchange. The elapsed time
during the chemical operation before the γ-ray measurement was approximately 12 minutes.
The distribution ratio (D) in the solvent extraction
is represented as
D = Aorg Vaq /Aaq Vorg ,where Aorg and Aaq are activities [Bq] in organic andaqueous phases, respectively, and Vorg and Vaq arevolumes [mL] in organic and aqueous phases, respectively. The extraction of trivalent lanthanide elements
by HTTA from the aqueous solution is represented by

Fig. 1. Automated rapid chemical operation apparatus forsolvent extraction.
∗

Department of Chemistry, Osaka University

Fig. 2. Variation fo log D with log [HTTA], where D =[Ln(TTA3 )]/[Ln3+ ]. The slopes of all lines are approximately.

109

the reaction:+→
Ln3+
aq + 3HTTAorg ← Ln(TTA)3 org + 3Haq .

A linear relationship with a slope of three is expected
for the plot of log D (where D = [Ln(TTA)3 ]/[Ln3+ ])as a function of log [HTTA]org .
The experimental result is shown in Fig. 2. The variations of the distribution ratio for the lanthanide ele-

110

ments against the concentration of HTTA in both theon-line and the batch experiments are shown by theclosed symbols and open symbols, respectively. The
least square ﬁts to each element are shown by various lines. It was found that the slopes of the log Dlog[HTTA] plots for each element were approximately
three and the distribution ratio in the on-line experiments agrees with that of the batch experiments.

RIKEN Accel. Prog. Rep. 38 (2005)

Reactions of 57 Mn implanted into solid oxygen (II)Y. Kobayashi, H. Nonaka,∗1 J. Miyazaki,∗1 K. M. Kubo,∗2 H. Ueno, A. Yoshimi, H. Miyoshi,∗3 D. Kameda,∗3
K. Shimada,∗3 D. Nagae,∗3 G. Kato,∗3 and Y. Yamada,∗1
We have performed an in-beam Mössbauer spectroscopic experiment using a short-lived 57 Mn beam,in order to study the electronic structures, especially
exotic high oxidation states, of 57 Fe atoms decaying from 57 Mn implanted into solid oxygen. From
our previously obtained in-beam Mössbauer spectra of57
Fe (← 57 Mn) implanted into KMnO4 between 11 K
and 155 K, the 57 Fe atoms occupying Mn sites in a
[MnO4 ]− tetrahedron were found to be in an unusually high valence state of Fe (VIII).1) In more reactive
matrices, Fe species with extraordinarily higher oxidation states are expected to be produced. In thisstudy, we carry out an implantation Mössbauer studyof 57 Fe (← 57 Mn) in solid O2 . We determine novel Feoxide species produced from the decay of 57 Mn witha high translational energy and compare them withthose obtained by the rare-gas matrix isolation technique with laser-ablated Fe atoms.2) The 57 Fe atoms
decaying from 57 Mn have an extremely higher energy
than the laser-ablated Fe atoms upon implantation anddecay, which provides important information on chemistry under extreme conditions and on the productionof novel species.
57
Mn particles were produced as RI beams following the nuclear projectile fragmentation of 58 Fe beams(E = 62 A MeV) with a Be target using RIPS, andsubsequently implanted into a solid O2 sample. An
enriched 58 Fe ferrocene (58 Fe (C5 H5 )2 ) compound was
employed as an ion source to obtain a larger 57 Mn
yield.
The in-beam 57 Fe (← 57 Mn) Mössbauer spectrum ofsolid O2 obtained at 18 K is shown in Fig. 1. The total
measuring time was 18 hr. The quality of this complicated spectrum was suﬃcient for detailed analysis.
This was the reason why the number of 57 Mn particles(approximately 5 × 106 particles/s) increased 20 times
that obtained in our previous experiments.
The oxidation of Fe is a fundamentally and chem-

∗1
∗2
∗3

Fig. 1. In-beam Mössbauer spectrum of 57 Fe (← 57 Mn)
implanted into solid oxygen at 18 K.

ically interesting subject because it is related to the
corrosion of materials and catalytic reactions. The
simplest oxidation of Fe is the reaction between an
Fe atom and an oxidizing gas. Yamada et al. investigated the reaction of laser-ablated Fe atoms with O2
gas by the rare-gas matrix isolation technique at low
temperatures.2) Reaction products were determined byconventional Mössbauer spectroscopy, IR spectroscopy,
and ab-initio molecular orbital calculations. They concluded that Fen clusters, FeO, Fe (O2 ), FeO3 , (O2 ) Fe
(O2 ), and OFeO species were produced and isolated
in the Ar matrix. Our present result could be analyzed using their Mössbauer parameters. Fe (O2 ) (Ain Fig. 1), FeO (B), and Fe2+ species with a low-spinstate (C), and an exotic high oxidation state (probably
Fe8+ , D) are preliminarily assigned. The observations
obtained by in-beam Mössbauer measurements will bereported elsewhere.
References
1) Y. Kobayashi et al.: J. Radioanal. Nucl. Chem. 255,
403 (2003).
2) Y. Yamada et al.: Appl. Radiat. Isot. 52, 157 (2000).

Department of Chemistry, Science University of Tokyo
International Christian University
Tokyo Institute of Technology

111

RIKEN Accel. Prog. Rep. 38 (2005)

Development of 83 Kr Mössbauer Spectroscopy
M. K. Kubo,∗1 Y. Kobayashi, Y. Kawaguchi,∗1 Y. Yamada,∗2 and H. Haba
Krypton is a rare gas (Rg) element and thus has
limited chemical reactivity. Immediately after the discovery of the reaction of xenon and ﬂuorine to yieldxenon ﬂuorides, the ﬁrst krypton compound KrF2 wassynthesized in 1963.1) Since then, continuous research
eﬀorts have been made in preparing various krypton,
xenon and argon compounds to investigate the natureof chemical bonds in these Rg compounds. For Kr compounds, only those containing ﬂuorine had been known
until the discovery of HKrCl in 19952) using ab initio
calculations. There have been a few attempts to synthesize novel Rg compounds containing Rg-C bonds.3)
In these attempts, the matrix-isolation-laser-excitation(MILE) technique was adopted. A Rg matrix is condensed onto a CsI substrate with a reactant compound,e.g., hydrogen cyanide at low temperatures. After condensation, the matrix is irradiated with a laser beam
to excite the reactant compound to form a stable Rg
compound. The compounds formed are conﬁrmed by
IR spectroscopy. In MILE experiments, a Rg atom canform a chemical bond with only one reactant molecule,because the reactant concentration is kept low (molar
ratio of Rg / reactant ≥ 1000). In 2003, compoundswith xenon and acetylene were prepared.4) Krypton
compounds with similar structures are believed to exist, but have not been experimentally conﬁrmed.
We have been applying the ion implantation method
to produce novel and rare chemical compounds ofiron using the RIKEN cyclotron in combination withemission Mössbauer spectroscopy as a characterization
method.5) By the method, we prepare various solid targets to react with incoming ions. We may observe thereactions of krypton with various solid materials using
the RIKEN cyclotron.
Fortunately, krypton has the Mössbauer active nuclide 83 Kr. Mössbuaer spectroscopy will provide information on the electronic states of krypton, such as thevalence state and electric ﬁeld gradient at the Kr nucleus, complementary to IR spectroscopy which gives
atom-atom bond parameters. Particularly, aiming at
the production of compounds consisting of a krypton and two or more reactant molecules beyond thescope of the dilute MILE condition, we have started a
new project on 83 Kr Mössbuaer spectroscopy using the
RIKEN cyclotron. As the ﬁrst step, we are setting up aMössbauer spectrometer for 83 Kr using a radioisotope
source 83 Rb (T1/2 = 86.2 d).
The nuclear level scheme of 83 Kr is shown in Fig. 1.
The Mössbauer level of 83 Kr is the ﬁrst excited state
∗1
∗2

112

Department of Chemistry, International Christian University
Department of Chemistry, Tokyo University of ScienceFig. 1. Energy levels of 83 Kr.

at 9.396 keV. Above this level, there is the metastablestate 83m Kr with a half-life of 1.83 h. 83 Kr Mössbauer
studies have been carried out since the 1960’s. Most of
the former studies used 83 Rb as the radiation source
embedded in solid matrices.6) We propose to use 83m Kr
as the radiation source separated from 83 Rb to reduce
the radiation background arising from 83 Rb. By depositing carrier-free 83m Kr on a cold plate and using
it as the source, we will be able to obtain Mössbauser
spectra of good quality.
Our plan for 83m Kr source preparation is as follows:
A CaBr2 target is irradiated with an α particle beamof 25 MeV. After the irradiation, the target is dissolved in water. By adding an (NH4 )2 CO3 solution toprecipitate and separate CaCO3 , the solution is passed
throuth a cation exchange resin column on which 83 Rb
is adsorbed. Within one day, 83 Rb and 83m Kr attainradiochemical equilibrium. The column is dried andattached to a gas handling line leading to the end nozzle facing the cryostat cold head. A slow stream ofhelium gas carries 83m Kr to the cold head to be usedas the Mössbauer source.
We carried out α particle beam irradiation and are
now verifying the processes of the chemical separation.
References
1) J. J. Turner and G. C. Pimentel: Science 140, 974(1963).
2) M. Pettersson, J. Lundell, and M. Räsänen: J. Chem.
Phys. 102, 6423 (1995).
3) For example, M. Pettersson, J. Lundell, L. Khriachtchev,
and M. Räsänen: J. Chem. Phys. 109, 618 (1998).
4) L. Khriachtchev et al.: J. Am. Chem. Soc. 125, 4695
(2003); V. I. Feldman et al.: J. Am. Chem. Soc. 125,4698 (2003).
5) For example, Y. Yamada et al.: RIKEN Accel. Prog.
Rep. 37, 112 (2004).
6) S. Bukshpan et al.: Int. J. Appl. Radiat. Isot. 27, 15(1976).

RIKEN Accel. Prog. Rep. 38 (2005)

Eﬀects of carnosine (β-alanyl-L-histidine) on theabsorption of iron in rats
K. Igarashi, S. Kimura,∗ and S. Enomoto
Iron deﬁciency is probably the most frequent nutritional disorder in the world. One of the main causative
factors is the poor absorption of iron, because nonheme
iron, the main form of dietary iron, has a low intestinal
absorption eﬃciency compared with heme iron. Furthermore, the absorption of nonheme iron is aﬀectedby the inhibitors such as phytic acid and polyphenols.
Therefore, the enhancement of nonheme iron absorption is important for improving iron nutrition.
It is well-established that the bioavailability of nonheme iron from food is enhanced by vitamins, organicacid, meat, poultry and ﬁsh. Ascorbic acid and citricacid maintain iron in a more soluble and absorbableform, and prevent its binding to inhibitory ligands.1)
Although meat stimulates nonheme iron absorption,
the factor in meat responsible for enhancing nonheme
iron absorption is yet to be identiﬁed.
Carnosine (β-alanyl-L-histidine) is observed in millimolar concentrations in the skeletal muscles andbrains of animals. It has been proposed to serve as anatural antioxidant in vivo.2) Recently, the pharmacological activity of the carosine-metal complex has beenstudied.3)
Thus, to investigate the eﬀects of carnosine for theabsorption of nonheme iron, we determined the change
in serum iron concentration in rats administered ferrous sulfate and carnosine using a cannulation system.
Eight-week-old male Wistar rats were purchased andhoused in stainless-steel cages. The method of cannula preparation was as described by Taguchi et al.
and Spannagel et al.4–6) After treatment, the rats wereplaced in Bollman-type restraint cages modiﬁed to provide the minimum restraint possible. Three days after surgery, the rats were administered 5 mg iron/rat
as ferrous sulfate with or without carnosine at a doseof 30 mg into the stomach simultaneously. Then the
blood was collected at regular intervals, plasma andblood cells were separated by centrifugation (3000 rpm
for 15 min). To determine the bioavailability of iron,serum iron concentration was measured using a kit by
the Nitroso-PSAP method.7)
The changes in serum iron concentration in rats areshown in Fig. 1. The serum iron concentration in rats
administered with ferrous sulfate reached its maximum
from 30 to 60 min, and decreased thereafter. On theother hand, the serum iron concentration in rats administered with ferrous sulfate in the presence of carno-∗

Fig. 1. Changes in serum iron concentration in rats. ◇:control, ■: ferrous sulfate, ●: ferrous sulfate withcarnosine. * Signiﬁcant diﬀerences were observed between ferrous sulfate-administered rats and ferrous
sulfate-administered rats with carnosine.

sine signiﬁcantly increased at 15 min, and remained
constant up to 45 min after treatment. The serumiron concentration in rats administered with ferrous
sulfate in the presence of carnosine was signiﬁcantly
higher than that in rats administered with ferrous sulfate after treatment for 15 min, indicating that the rats
administered ferrous sulfate with carnosine promoted
the uptake of iron into the body. Although we further determined the iron incremental area to investigate iron absorption, no signiﬁcant diﬀerence was observed between ferrous sulfate-administered rats andferrous sulfate-administered rats with carnosine.
These results suggest that carnosine may facilitate
the velocity of iron absorption of ferrous sulfate. However, the stability constant of carnosine for iron was
lower than that for other metals. It is assumed that
carnosine has a mechanism for facilitating the velocityof iron absorption other than its chelating property.
References
1) I. M. Zijp et al.: Crit. Rev. Food Sci. Nutr. 40, 371(2000).
2) M. A. Babizhayev et al.: Biochem. J. 304, 509 (1994).
3) M. Seiki et al.: Folia Pharmacologica Japonica 95, 257(1990).
4) S. Taguchi et al.: Jpn. J. Clin. Physiol. 24, 241 (1994).
5) A. W. Spannagel et al.: Am. J. Physiol. 270, G128
(1996).
6) K. Igarashi et al.: RIKEN Accel. Prog. Rep. 37, 115(2003).
7) M. Saito et al.: Bunseki Kagaku 30, 635 (1981).

Graduate School of Human Life Sciences, Showa Women’s
University

113

RIKEN Accel. Prog. Rep. 38 (2005)

Cannulation study on the absorption of iron in rats: Eﬀect ofL-catechin as a polyphenol
K. Igarashi, S. Kimura,∗ and S. Enomoto
Polyphenols are widely present in the human diet.
The consumption of polyphenols in the USA is estimated at 1 g/d,1) and as much as 0.5 g/d is consumed
from tea in the UK.2) Several thousand molecules havebeen identiﬁed in various plant species, where they
have several functions. Tannins give astringency or bitterness, and anthocyanins give color to red fruits suchas strawberries and grapes. Others such as isoﬂavone
phytoestrogens in soy bean are restricted to a given
food source. Recent studies have shown that polyphenols are reducing agents similar to vitamin C, vitamin
E and carotenoids. They may prevent various diseases
associated with oxidative stress, such as cancers, cardiovascular diseases and inﬂammations.
On the other hand, polyphenols are inhibitors of theiron absorption. Phenolic compounds bearing catecholgroups (e.g., catechin) or galloyl groups (e.g., gallicacid) have iron-binding properties. Tea, coﬀee, cocoa,
red wine, many vegetables, grains, herbs and spices
contain such phenolic compounds and all have an invitro inhibitory eﬀect on the iron absorption.
Iron is one of the essential trace elements for humans. The dietary form of iron plays a role in absorption and also in iron balance. Heme iron is absorbed
as an intact porphyrin structure by speciﬁc receptors
in the brush border mucosa3) and therefore heme ironis not aﬀected by other constituents of diet. Whilenonheme iron is present in foods as ferric and ferrous
salts. In intestinal lumen, iron is released and rapidly
chelated by other constituents in food. There are two
types of chelator. One class called enhancers forms soluble low-molecular-weight chelates that are absorbed
easily and the other class called inhibitors forms insoluble high-molecular-weight chelates that are unavailable
for absorption.
Thus, we determined the eﬀects of catechin on theabsorption of iron in rats. We used a cannulation system for investigating iron absorption in rats administered with polyphenol because it is eﬀective in determining the biological response to infused samples inthe stomach of conscious rats.
Eight-week-old male Wistar rats were purchased andhoused in stainless-steel cages in a temperature- and∗114

Graduate School of Human Life Sciences, Showa Women’s
University

light-controlled room. The methods of cannula preparation and animal treatment were shown previously.4)
Three days after surgery, the rats were administeredcatechin and ferrous sulfate into the stomach simultaneously. Then blood was collected at regular intervals, and plasma and blood cells were separated by centrifugation (3000 rpm. for 15 min). To determine thebioavailability of iron, serum iron concentration wasmeasured using a kit by the Nitroso-PSAP method.5)
The serum iron concentration in ferrous sulfateadministered rats increased to 412 µg/dl from 15 to
30 min. It maintained the same level up to 60 min
and then gradually decreased. The serum iron concentration of rats administered ferrous sulfate and catechin reached 457µg/dl after administration for 15 min,and remained constant up to 30 min. The serum ironconcentration of rats administered ferrous sulfate andcatechin was signiﬁcantly high compared with that inrats administered ferrous sulfate at 15 min. No significant diﬀerence was observed between ferrous sulfateadministered rats and ferrous sulfate-administered rats
in the presence of catechin, indicating that the absorption of iron was not inhibited by catechin in the rats
administered with ferrous sulfate.
The result of this study demonstrates that catechindoes not aﬀect the iron absorption of ferrous sulfate.
However, catechol groups are considered to be the phenolic constituents mainly responsible for the iron binding capacity of condensed tannins. Although Bruneet al. reported that the binding property of a galloylgroup was higher than that of a catechol group,6) itis thought that the result of this study is due to theamount of catechin being very small compared withthat of ferrous sulfate.
References
1) J. Kuehanau: World Rev. Nutr. Diet 24, 117 (1979).
2) G. V. Stagg et al.: J. Sci. Food Agric. 26, 1439 (1975).
3) R. Grasbeck et al.: Biochim. Biophys. Acta 700, 137(1982).
4) K. Igarashi et al.: RIKEN Accel. Prog. Rep. 37, 115(2004).
5) M. Saito et al.: Bunseki Kagaku 30, 635 (1981).
6) M. Brune et al.: Eur. J. Clin. Nutr. 43, 547 (1989).

RIKEN Accel. Prog. Rep. 38 (2005)

Influence of pantothenic deficiency on intestinal flora in rats
M. Hasama,∗1 Y. Iizuka,∗2 N. Iwasaki,∗2 S. Enomoto, and S. Kimura∗1
Pantothenic acid (PA), which is a component ofcoenzyme A (CoA) and acyl-carrier protein, is an essential nutrient for many animals. The majority of PA
in food is present as a component of CoA that participates in the metabolism of carbohydrate, liquid andprotein. CoA has been associated with more than 70
enzymatic reactions in vivo. Human PA deﬁciency israre, because it is widely distributed in food.
In clinical medicine, disulﬁde pantetheine, pantethine (PaSS), is used as a remedy for atonic constipation and a postoperative paralyzed intestine. Because
PaSS is known to increase intestinal motility, a possible
mechanism of increasing intestinal motility by PaSS isthought to be deﬁned by several factors. One factor isthe energy production of muscle contraction. Muscle
contraction depends on ATP and is closely associatedwith CoA. On the other hand, intestinal ﬂoras such as
Lactobacillus also play an important role in intestinal
motility. Lactobacillus requires PA and PaSS as essential nutrients. Lactobacillus and its metabolic substance are closely associated with intestinal motility.
These facts indicate that PA and PaSS are important
vitamins that support intestinal motility.
In this study, we determined whether PA deﬁciency
decreases intestinal motility in rats, and discussed its
mechanism by changing the intestinal ﬂora and reducing the energy metabolism.
We observed that the food transit time in PAdeﬁcient rats was signiﬁcantly delayed (control, 7.3 ±2.7 hr; PA deﬁciency, 11.8 ± 2.0 hr, p < 0.01). In
addition, the number of contractions in the PA deﬁcient rat cecum was signiﬁcantly reduced (control,
715 ± 36 counts/hr; PA deﬁciency, 215 ± 23 counts/hr,
p < 0.01). These results suggest that PA deﬁciency
obviously aﬀects intestinal motility and delays foodtransport in the large intestine.
Decreasing intestinal motility in PA-deﬁcient rats affects the alternation of the intestinal ﬂora. However,the cultivation of the intestinal ﬂora by anaerobic culture is very diﬃcult. Thus, we measured the concentrations of materials produced such as fatty acids andorganic substances produced by a bacterium.
Table 1 shows the concentrations of various organic
acids in the cecum. The concentrations of main shortfatty acids (SCFAs), such as propionate, acetate, andn-propionate, decreased, while that of succinate increased in PA-deﬁcient rats. Approximately 95% of
SCFAs in the large intestine are immediately absorbed
from large intestinal epithelial cells and recycled as nutritional sources.1) Approximately 4.7% of the total en∗1
∗2

Graduate School of Human Life Science, Showa Women’s
University
Tokyo R&D Center, Daiichi Pharmaceutical Co., Ltd.

Table 1. Concentrations of various organic acids in rat cecum.
Organic Acid
AcetatePropionate
n-Butirate
SCFA Total
Succinate

Controlµmol/cecum
62.87 ± 26.32
30.10 ± 13.34
27.16 ± 13.09
93.02 ± 33.28
13.33 ± 8.21

PA deﬁciency
22.25 ± 6.96§1
11.06 ± 5.81§2
9.48 ± 4.33
33.41 ± 8.52§1
70.06 ± 32.17§1

Each value represents the mean ± S.D. of data fromeight rats. §1 and §2 indicate signiﬁcant diﬀerences between control group and pantothenic acid (PA) deﬁciency group. §1 p < 0.01, §2 p < 0.05.

ergy in rats induce the uptake of SCFAs, which are metabolized by intestinal ﬂoras.2) Decreasing SCFA concentration in PA-deﬁcient rats is associated with theloss of energy in the intestine.
As described above, PA is an essential nutrient for
intestinal ﬂoras. In particular, Lactobacillus bifidus
requires pantetheine, which is a PA derivative. Citrate lyase (EC4.1.3.6), which produces acetate andoxalo acetate from citrate, is extracted from Klebsiella aerogene and Streptococcus diacetilactis.3) Citramalate lyase (EC4.1.3.22), which produces acetate andpyruvate from citra-maleate, is puriﬁed from Clostridium tetanomorphum.4) These enzymes interact with4 -phospho-pantetheine, which is a PA-derivative. The
above-mentioned bacteria are considered to require PA
and its derivative.
Our results indicate that PA is eﬀective for the control of intestinal ﬂoras. In the PA- and PA-derivativedeﬁcient situations, the amount of good bacteria suchas L. bifidus is low. This phenomenon is speculated tobe caused by decreasing SCFA concentration.
In this study, succinate in the intestine was foundto suppress intestinal motility. An organic acid in thececum was determined to increase the concentration of
succinate in PA-deﬁcient rats.
Therefore, we conclude that the animal of good bacteria such as L. bifidus is low in the intestine of PAdeﬁcient rats. This phenomenon changes the concentration of organic acids, decreases the production of
SCFAs and increases the concentration of succinate,resulting in a decrease in intestinal motility.
References
1) W. V. Engelhardt, K. Roennau, G. Rechkemmer, and
T. Sakata: Anim. Feed Sci. Technol. 23, 43 (1989).
2) N. I. McNeil: Am. J. Clin. Nutr. 39, 338 (1984).
3) P. Dimroth and H. Eggerer: Proc. Natl. Acad. Sci. USA
72, 3458 (1975).
4) M. Singh, J. B. Robinson, and P. A. Srere: J. Biol.
Chem. 252, 6061 (1977).

115

RIKEN Accel. Prog. Rep. 38 (2005)

Eﬀect of pantotenic acid and pantethine in aging rats
M. Hasama,∗ R. Sato,∗ E. Mizukami,∗ K. Okiyama,∗ S. Enomoto, and S. Kimura∗
Atonic constipation is a serious problem for elderly
people. In this situation, a disulﬁde type of pantetheine, pantethine (PaSS), is widely used to increase intestinal motility in clinical medicine. Because synthesis from pantothenic acid (PA) to coenzyme A (CoA)is decreased,1) the biosynthetic reaction rate of pantetheine from PA inﬂuences aging.2)
In this study, to identify the interaction of PA deﬁciency in aging, we determined the eﬀect of PA andPaSS on aging rats. We raised PA-deﬁcient Wistar male rats for 23 months and divided them into
three groups; PA deﬁcient, PA intake and PaSS intake groups. After raising them for one more month,
we measured each rat’s heart CoA concentration. As
shown in Fig. 1, the CoA concentration in the PA intake group slightly increased in contrast to that of the
PA deﬁcient group. On the other hand, the CoA concentration in the PaSS intake group increased signiﬁcantly and aided recovery from PA deﬁciency. These
results suggest that the reaction from PA to pantetheine is the rate-limiting reaction in aging animals.
We observed the food transit time (TT) to identify
the degree of intestinal motility. TT indicates the timefrom intake to excretion. The TT delays in normal rats
take an average of 7–9 hours. PA-deﬁcient aging rats
had a TT of over 10 hours. Note that TT in the PA
intake group did not decrease, in contrast to that in
the PaSS intake group where it decreased. Intestinal
motility recovery takes place with PaSS wherein thebiosythesis of CoA is high, but not with PA; CoA concentration correlates with intestinal motility. This result supports those in clinical medicine wherein PaSSaﬀects atonic constipation.
In addition, we observed a concentration of organicacid patterns in aging rat cecum. As shown in Fig. 2,

Fig. 1. Concentration of CoA in hearts of aging rats.
PA: pantothenic acid, PaSS: pantethine, §1 indicatessigniﬁcant diﬀerence between PA deﬁcient group andPaSS intake group (p < 0.01). §2 indicates signiﬁcantdiﬀerence between PA intake group and PaSS intake
group (p < 0.05).
∗

116

Graduate School of Human Life Science, Showa Women’s
University

Fig. 2. Concentration of short chain fatty acid (SCFA) andsuccinate in cecum of aging rats.
PA: pantothenic acid, PaSS: pantethine, § indicates signiﬁcant diﬀerence between PA deﬁcient group and PaSS
intake group (p < 0.01).

the PaSS intake group incurred an increase in shortchain fatty acid (SCFA) concentration, but the PA intake group did not. On the other hand, the PaSS intake group incurred a decrease in succinate, but the
PA intake group did not. In our previous study, PA
deﬁciency caused a decrease in SCFA and an increasein succinate because the amount of good bacteria suchas L. bifidus decreased. With the intake of PaSS, aging rats recovered from PA deﬁciency and utilized thegood bacteria in there intestinal ﬂora.
In conclusion, PaSS is more eﬀective than PA in aiding the recovery of PA-deﬁcient aging rats. These results showed that the biosynthesis reaction rate fromPA to pantetheine was delayed.
These results are for the case of rats, however, we canspeculate that for elderly people, CoA concentration
likewise decreases. Our results indicate that atonic
constipation in elderly people is closely related to PA
deﬁciency.
References
1) S. Kimura: in Vitamin, edited by Japanese Society ofVitaminology (Asakura Shoten, Tokyo, 2000), p.255.
2) E. Coriandori: Naturwissenschaften 47, 183 (1960).

RIKEN Accel. Prog. Rep. 38 (2005)

Brain uptake behavior of 24 Na, 28 Mg, 43 K and 47 Ca byintranasal administration
Y. Kanayama,∗ H. Haba, S. Enomoto, and R. Amano∗
Olfactory receptor neurons are in contact with theenvironment in the nasal cavity and the olfactory bulbsof the brain. Therefore, when certain kinds of proteins, viruses or metals are administered into the nasal
cavities, the axonal transport of the olfactory neuron
plays an important role in the pathway that directly
enter the brain bypassing the blood-brain barrier.1)
Recently, we demonstrated that K+ -mimic ions, Rb+ ,Cs+ , and Tl+ are transported into the olfactory bulbs
and delivered to other brain regions by intranasal administration.2,3) However, the underlying mechanisms
and physiological roles of the axonal transport of theseK+ -mimic ions are poorly understood. Previously,
we attempted simultaneous tracing of 24 Na+ , 28 Mg2+ ,43 +K , and 47 Ca2+ for clarifying their olfactory transport using the multitracer from a Ti target.4)
The multitracer was obtained from a Ti foil target
irradiated with a heavy-ion beam of 135 MeV/nucleon
for 1 hour using the RIKEN Ring Cyclotron and prepared as a physiological saline solution.4) The multitracer solution was intranasally administered to ICR
mice (8-week-old, male). Six, 12, 24 and 48 h after theadministration, mice were sacriﬁced, and then blood(BL), liver (LV), ethmoturbinals and brain samples
were obtained. The brain was separated into 3 regions,the olfactory bulb (OB), the forebrain including thelateral olfactory tract, olfactory tubercles, and piriform
cortex (FB), and the rest of the brain (RB). Activities were measured by γ-ray spectrometry using highpurity Ge detectors. The uptakes and uptake rates ofeach obtained sample were given as a percentage of theadministered dose (%dose and %dose/g, respectively).
The mean and standard deviation for three mice were
determined for each set of elapsed time points.
Figure 1 shows the uptake behaviors of 24 Na+ ,28
Mg2+ , 43 K+ and 47 Ca2+ in the blood, liver, andbrain regions following the intranasal administrationof the multitracer. At 6 h, the brain regional distributions of 24 Na, 28 Mg and 43 K showed similar levels to
those of our preliminary study.4) The highest 43 K uptake rate was found in the OB at 6 h and decreased until 24 h. Meanwhile the uptake rate in the FB slightly
increased until 12 h. In contrast, no regional diﬀerence was observed in the brain uptake rates of 24 Na
throughout 48 h.
As for the alkaline earth metal ions, 28 Mg and 47 Ca∗

Fig. 1. Uptake rates of 24 Na+ , 28 Mg2+ , and 43 K+ in the
blood, liver, and brain regions 6, 12, 24 and 48 hours
after intranasal administration. IN: intranasal administration; OB: the olfactory bulbs; FB: the fore brain;
RB: the rest of the brain.

were highly accumulated in the ethmoturbinals, which
was virtually the access site, and also in the bone in thesample itself. There was a large diﬀerence in the uptake rate in the OB between 28 Mg and 47 Ca. Although
the 47 Ca uptake in the ethmoturbinals maintained ahigh level until 48 h, the 28 Mg uptake rate decreased
with time in the ethmoturbinals and increased at 12 hin the OB. The 28 Mg uptake rate showed a generallyhigh level in the OB. However, unlike 43 K, the 28 Mg
uptake rate in the OB increased until 12 h. On theother hand, 47 Ca uptake was at a very low level suggesting that most of the administered 47 Ca absorbed
and bound to the bone in the ethmoturbinals.
The results indicate that Mg2+ and K+ are directlytransported from the nostril to the brain via the olfactory pathway, and their transport mechanism might bediﬀerent due to their diﬀerent transport speed.
References
1) S. Mathison, R. Nagilla, and U. B. Kompella: J. Drug
Target. 5, 415 (1998).
2) Y. Kanayama, T. Tsuji, S. Enomoto, and R. Amano:
RIKEN Accel. Prog. Rep. 36, 123 (2003).
3) Y. Kanayama, R. Amano, K. Washiyama, T. Irie, S.
Enomoto, K. Kawai, and N. Tonami: Eur. J. Nucl. Med.
Mol. Imaging. 30 Suppl. 2, S296 (2003).
4) Y. Kanayama, H. Haba, R. Hirunuma, S. Enomoto, and
R. Amano: RIKEN Accel. Prog. Rep. 37, 135 (2004).

School of Health Sciences, Faculty of Medicine, Kanazawa
University

117

RIKEN Accel. Prog. Rep. 38 (2005)

Preliminary study on 88 Y olfactory transport: Animal experiment
M. Ono,∗ Y. Kanayama,∗ H. Haba, S. Enomoto, and R. Amano∗
Some materials are transported from the nose, whichis connected to the external environment, directly tothe brain, which is the central organ of life activity.
The substance transportation system is termed olfactory transport. However, the brain possesses a special
mechanism, the blood brain barrier (BBB), that protects the brain from harmful substances in the bloodstream, while supplying the brain with the required nutrients for normal functioning. In the olfactory transportation system, a material is directly transported via
an olfactory nerve from the nasal cavity to the brain
without passing through the BBB. Recently, the importance of the olfactory transportation system in thetransportation of new medicines into the brain has
been recognized by the medical field and its importance as a new pathway for heavy metals or radioactive materials in humans has been recognized by the
toxicology field.
In a RIKEN multitracer screening experiment, wefound that nasally administered 83 Rb is transported
directly into the brain. A single-tracer experiment using 86 Rb1) showed that the pathway was the olfactorytransportation system. To search for other elements
related to olfactory transport besides Rb+ , we again
carried out a multitracer screening in detail. Previously, we also found that 88 Y may be transported via
the olfactory transportation system.2) In this study, we
attempted to clarify this result using the 88 Y radioactive tracer.
Yttrium-88 was produced using 88 Sr(p, n)88 Y anda SrCO3 target with 13.3 MeV protons at the RIKENAVF Cyclotron. Carrier-free 88 Y was isolated by thesolvent extraction method. The extracted 88 Y sample
was added to 200 µl of HCl and the acid was removedby evaporation. The residue was then dissolved with
distilled water and dried. The 88 Y injection solution
was prepared by dissolving the residue with 0.9% physiological saline. ICR mice (7 weeks old, male) wereused in this experiment. The mice were divided into
two groups, the intranasally administered (IN) groupand the intravenously administered (IV) group, which
was the control group (n = 4). In intranasal administration, 10 µl of 88 Y solution was administered to both
nasal cavities. Each mouse was sacrificed under anesthesia either 6, 24 or 48 hours after the administration,and the extracted brain was divided into three parts:∗

118

School of Health Sciences, Faculty of Medicine, Kanazawa
University

the olfactory bulb (OB), the section including the piriform cortex (Pir) and the rest of brain (RB). We measured γ rays using a well-type scintillation counter after weighing each part, and calculated the uptake rate(%dose/g).
As shown in Fig. 1, in the OB region of the IN
group the uptake rate is higher than that of the IV
group in all the observation periods. The result shows
the same tendency as the previous results from multitracer screening.2) 88 Y olfactory transportation was
confirmed in this experiment, but the uptake rate waslower than the previous results. This is due to a chemical property of Y : Y3+ easily hydrolyses and becomes
colloidal at approximately pH 7.
Y is one of the rare-earth elements and generally
resemble the series of elements of the lanthanide andactinide groups. It is considered that actinide elements
are similarly transported via the olfactory transportation system. Knowledge of their transport and in theinfluence on the central nervous system has become
increasingly important from the viewpoint of environmental radioactivity and toxicology.

Fig. 1. Uptake rates of 88 Y in olfactory bulb. The bar andthe line represent the mean ± S.D. of four mice.

References
1) Y. Kanayama, R. Amano, K. Washiyama, T. Irie, S.
Enomoto, K. Kawai, and N. Tonami: Eur. J. Nucl. Med.
Mol. Imaging. 30 Suppl. 2, S296 (2003).
2) M. Ono, R. Amano, and S. Enomoto: Proc. 6th Workshop on Environmental Radioactivity, Tsukuba, 2004-3,(KEK, 2004) p. 291.

RIKEN Accel. Prog. Rep. 38 (2005)

Analysis of skin distribution of 65 Zn in hairless mice treated with65
Zn-labeled zinc compounds by oral supplementation
H. Yasui,∗ H. Nishimura,∗ H. Haba, R. Hirunuma, S. Enomoto, and H. Sakurai,∗
An increase in ultraviolet light (UV) exposure on
human skin has been shown to enhance severe dermal
damage (phototoxicity), inﬂammation, and prematureskin-photoaging.1) The harmful eﬀects of UVA exposure are associated with the generation of reactive oxygen species (ROS).2) In our eﬀorts to ﬁnd agents for
reducing the skin damage of live mice under UVA exposure, we have found the potency of zinc(II) ion withregard to the suppression of ROS generation in theskin.3) Zinc (Zn) is known to be one of the most important essential trace elements existing ubiquitously in
all living systems.4) Among the many pharmacologicaland nutritional roles of Zn(II), its anti-inﬂammatory
activity is the most striking.4) On the basis of these results regarding the physiological role of Zn(II), we havefurther examined whether orally administered ZnCl2
and a Zn(II)-picolinate complex, Zn(pic)2 , suppress
ROS generation in the skin. First, we report herein
the skin distribution of orally supplemented ZnCl2 orZn(pic)2 in terms of monitoring 65 Zn levels after theadministration of 65 Zn-labeled compounds.
65
Zn in the chemical form of ZnCl2 in 0.5 mol/L HCl,
was obtained from RIKEN (Wako, Japan). 65 Zn solution was gently dried and then the residue was redissolved in a physiological saline solution (activity
concentration = 370 kBq/mL). ZnCl2 dissolved in thesaline solution was mixed with 148 kBq of 65 Zn, andthe preparation was completed to a ﬁnal volume of
4 mL with the saline solution. While Zn(pic)2 and picolinic acid (5% of complex) dissolved in the saline solution were mixed with 148 kBq of 65 Zn, the saline solution was added to the preparation for a ﬁnal volume of
4 mL, and then the preparation was labeled with 65 Zn
by leaving the preparation at 25◦ C overnight. The radioactivity administered to each mouse was 370 kBq
of 65 Zn/kg of body weight. Male hairless mice (5weeks old), weighing 25 g, were given the saline solution of 65 ZnCl2 or 65 Zn(pic)2 by single oral administration using gavage at a dose of 10 mg Zn/kg of bodyweight. After administration, each group of mice wasmaintained in polyethylene cages with a stainless-steel
grated ﬂoor and fresh chip sawdust below the ﬂoor
to prevent the urine and feces from coming into contact with mice and thus to avoid coprophagy. At 0–
72 hr after treatment, the mice were sacriﬁced underanesthesia with ether and organs such as skin were
removed. The organs were immediately weighed andtransferred to polyethylene tubes for a gamma counter.
The radioactivities due to 65 Zn amounts in organs were∗counted by an Aloka ARC-360 autowell gamma system(Tokyo, Japan) using the peak area of 1115.5 keV due
to 65 Zn nucleus (half-life of 65 Zn, 244.26 day).
Figure 1 shows the time-dependent distribution of65
Zn in the skin of hairless mice treated with 65 Znlabeled ZnCl2 (open circle) or Zn(pic)2 (closed circle)
by single oral administration at a dose of 10 mg Zn/kg
of body weight, using the gavage. Interestingly, 65 Zn
levels in the skin of mice treated with 65 Zn(pic)2 weresigniﬁcantly higher than those of mice treated with
65
ZnCl2 at 24 and 72 hrs as well as at 12 hr after administration, indicating that the actions of Zn on theskin are more enhanced and prolonged by the supplementation of Zn(pic)2 than those of 65 ZnCl2 . Theseﬁndings will be useful in developing orally active Zn
compounds for reducing UVA-induced ROS generationin the skin and thus for preventing skin damage after
UVA exposure.

Fig. 1. Time-dependent distribution of 65 Zn in skin of hairless mice after single oral administration of 65 Zn-labeled
ZnCl2 (open circles) or Zn (pic)2 (closed circles). Significance levels: * p < 0.05 and ** p < 0.01 of Zn (pic)2
group vs. ZnCl2 group at the same sampling time.

References
1) H. Masaki, Y. Okano, and H. Sakurai: Biochim. Biophys. Acta 1428, 45 (1999).
2) J. Krutmann: J. Dermatol. Sci. 23, S22 (2000).
3) H. Nishimura, H. Yasui, and H. Sakurai: Biomed. Res.
Trace Elem. 14, 239 (2003).
4) B. L. Vallee and K. H. Falchuk: Physiol. Rev. 73, 79(1993).

Department of Analytical and Bioinorganic Chemistry,
Kyoto Pharmaceutical University

119

RIKEN Accel. Prog. Rep. 38 (2005)

Excretion rate of bio-trace elements in bile of rat
under oxidative stress of Se-deficiency
K. Endo, K. Yamasaki, M. Tsukada, A. Okajo, K. Matsumoto, C. Honda,∗
K. Matsuoka,∗ R. Hirunuma, and S. Enomoto
Reactive oxygen species (ROS) are formed as a resultof an inevitable production process of the metabolismof an aerobic organism. The excessive ROS may possibly cause senility, cancer, and disease. On the other
hand, it is known that living organisms have antioxidant systems. Their antioxidant enzymes contain metals as active centers. It is also known that Se plays aprotective role against oxidative stress in vivo. Our
previous study showed that the concentration of Selenium (Se) in the diet inﬂuences the concentration of
Se in the blood, liver, and spleen.1) Bile is excreted
to a duodenum from the liver in the detoxication ofheavy metals. Under oxidative stress of Se-deﬁciency,
it is expected that the composition and the excretionof heavy metals in bile will be changed.
In this experiment, we examined the kinetics behaviors of metal ions which are related in vivo redox regulation systems such as Se, iron (Fe), manganese (Mn),cobalt (Co), and zinc (Zn) in the bile of Se-deﬁcient(SeD) rats using the multitracer (MT) technique.
Wistar mother rats, which were on 15th day after
pregnancy, were fed on a SeD diet (Oriental Yeast Co.,
Ltd.) and ultrapure water. Newly born rats were kept
with their own mother for four weeks. Then the young
rats were weaned, and fed on the SeD diet and ultrapure water until the experiments were performed. The
male rats were used for experiments at 8 weeks of age
as SeD groups. Normal male Wistar rats of the sameage as the SeD group were purchased and used as anormal control group.
The MT was prepared from silver foil irradiated with
N-14 beams of 135 MeV/nucleon at the RIKEN-ring
cyclotron. A saline solution containing MT was injected intravenously to SeD and normal rats. The
biliary duct of a Wister rat was cannulated with apolyethylene tube under Nembutal anesthesia. Afteradministration of MT solution, their bile was collected
in a polyethylene tube every 10 min for 60 min. γRay spectra of the bile samples were measured with ahigh-purity Ge semiconductor detector equipped witha multichannel analyzer.
The excretions (%) of Se, Sr, Mn, and Co were determined. The initial excretion rate for an element wasestimated by the ratio of the corresponding radioactivity of the bile of the ﬁrst 10 min collection to theradioactivity of the total injected MT solution. The
results of the excretion of each element into bile areshown in Fig. 1. The excretion rate of Se was high fornormal rats for about 10 min after the MT administra∗

120

Showa Pharmaceutical University

Fig. 1. Excretion (%) of metal ions into bile of (a) normaland (b) Se-deficient rats.

tion, and was evidently decreased for SeD rats to 1/6of that found for normal rats. As and V showed relatively slow excretion rates for normal rats, and were
not measured for SeD rats. On the other hand, theexcretion rates of Sr, Mn and Co into bile increased
to about 1.6, 7, 12 times greater than those of normal
rats, respectively.
The radioactivities of the nuclides increased toplateau values about 20 min after administration. The
excretion rate of Se into bile in a SeD rat was about 1/5
slower than that in a normal rat. Although the excretion rates of metal ions into bile for SeD and normal
rats were measured within 60 min of administration,none of the radioactivities of Fe and Zn were foundin this time range. This indicates that both elements
were absorbed and accumulated in the liver and otherorgans, while other elements were excreted into bile. It
is known that Fe(III) binds to transferine in blood andthat the complexes are transferred to the liver, spleen,
and/or bone marrow by blood circulation, where Fe isstored as ferritin or hemocyderine. In the liver, hemeiron is metabolized, and the Fe is excreted into bile,and reabsorbed at the duodenum. It is known that thebiological half-life of Fe is long (the eﬀective half-life isapproximately 42 days). Therefore, the radioactivitiesof 59 Fe were not observed within the time range usedin this work. In blood, nearly 70% of Zn binds to albumin, and 30% of the metal binds to α-macro-globulin,
and in liver it is stored as Zn-metallothionein. Zn isused for the active centers of many enzymes. Therefore, 65 Zn is also not excreted into bile soon after administration of MT.
Reference
1) K. Matsumoto et al.: Accel. Prog. Rep. 33, 116 (2000).

RIKEN Accel. Prog. Rep. 38 (2005)

Distributions of technetium and rhenium in radish plants
grown in nutrient solution culture†
K. Tagami,∗ S. Uchida,∗ N. Ishii,∗ R. Hirunuma, H. Haba, and S. Enomoto
Among technetium isotopes, 99 Tc is of potential
long-term importance in the environment because of its
long half-life (2.1×105 y) and its high ﬁssion yield from235
U and 239 Pu (approximately 6%). Thus, knowledgeof the behavior of 99 Tc from the soil to plant systems
is of special interest. However, the amount of 99 Tc in
the natural environment is at ultratrace levels even in
the soil,1) and therefore, the behavior of 99 Tc in theenvironment is unclear. Rhenium can be considered asa potential chemical analogue of Tc, although no data
are available for terrestrial plant samples because Re
is one of the rarest elements in the earth’s crust. If aterrestrial plant absorbs Re at a rate as high as thatreported for Tc and their uptake behaviors are similar,
Re can be used as a chemical analogue of Tc. However,no study from this viewpoint has been carried out yet.
Radish seedlings were grown in a nutrient solution
for about 1 month. Then, each plant was transplanted
to a 120 mL plastic vessel containing 40 or 60 mL of
new nutrient solution. In Run-A, 95m TcO−
4 and multitracers2) including 183 ReO−
4 were added to the nutrient solution to obtain 2.7×10−17 mol/mL (2.1 Bq/mL)
95m
Tc and 1.6×10−17 mol/mL (1.1 Bq/mL) 183 Re solutions, while 99 Tc and a multielement solution, XSTC8 (SPEX), were added in Run-B. The concentrations of 99 Tc and satable Re in Run-B, which are
0.69 × 10−12 mol/mL and 54 × 10−12 mol/mL, respectively, were markedly higher than those in Run-A.
The plant samples were in contact with the solution
through their ﬁne roots for 1–3 d. Then, the plants
were carefully removed from the solution. After rinsing and drying their ﬁne roots, the plants were separated into leaves, and ﬂeshy and ﬁne root parts. Eachsample part was weighed and oven-dried (60◦ C, 72 h).
The activities of the radioisotopes in the nutrient solution and the plants (Run-A) were measured using a
Ge detecting system (Seiko EG&G Ortec). In Run-B,
the concentrations of stable Re and 99 Tc were measured by ICP-MS (Agilent 7500a, Yokogawa analyticalsystems).
The amount of nutrient solution taken up by theplants increased with time for both runs, while the relative concentration ratios (C/C0 ) of Tc and Re in the
nutrient solution obtained after and before the exposure period did not change as shown in Fig. 1. That is,
the uptakes of Tc and Re by the plants were the sameas that of water. Comparing the results of Run-A and
Run-B, the concentration of Re, which was about 80†∗

Condensed from the article in Appl. Radiat. Isot. 61, 1203
(2004)
National Institute of Radiological Sciences

Fig. 1. Relative concentration ratios (C/C0 ) of isotopes
in nutrient solution and water loss from the vessel byradish.

fold that of Tc in Run-B, did not decrease the rate of
Tc uptake. Cataldo et al.3) reported that an excess−
amount of ReO−
4 did not reduce the rate of TcO4 absorption, thus Re could not be a biological analogueof Tc. However, from the results of the present study,
one possible explanation for the failure of ReO−
4 to inuptake
mechanism
hibit Tc uptake is that the ReO−
4
is the same as that of TcO−
4 , thus the plants cannot
recognize any diﬀerence between the two elements.
The distribution ratio of an isotope, deﬁned as the‘amount in a plant part’ divided by the ‘total absorbed
amount’, is shown in Fig. 2 for the samples collected
on 3 d after transplanting. In each experiment, thedistributions of Tc and Re in the plants were almost−
the same. Both TcO−
4 and ReO4 absorbed by the ﬁneroots were translocated rapidly to the leaves and ﬂeshy
roots. The behaviors of other elements were diﬀerent
from those of Tc and Re.
From these results, we assumed that Tc and Re behave similarly in radish plants. The results strongly
suggest that Re could be used as a chemical analogueof Tc in soil solutions for studies of plant uptake.

Fig. 2. Distribution ratios of isotopes in fine roots, fleshyroots and leaves of radish plants after 3 d contact.

References
1) K. Tagami and S. Uchida: J. Nucl. Radiochem. Sci. 3,
1 (2002).
2) F. Ambe: J. Radioanal. Nucl. Chem. 243, 21 (2000).
3) D. A. Cataldo, R. E. Wildung, and T. R. Garland:
Plant. Physiol. 73, 849 (1983).

121

RIKEN Accel. Prog. Rep. 38 (2005)

Comparison of leaching and sorption behavior of various ions insoil-water system based on ICP-MS and multitracer analyses
S. Mitsunobu,∗ Y. Takahashi,∗ R. Hirunuma, H. Haba, and S. Enomoto
Soil contamination whose source is natural or anthoropogenic is still widely found in the world. As
an example of natural phenomena, it has been reported that more than ten million people are suﬀering from pollution of groundwater concentrated higharsenic in Bangladesh and India.1) However, the detailed mechanism for the high concentration of arsenic
has not been understood completely. To understandthe mechanism of reactions in the soil-water system, we
performed both leaching and sorption experiments tounderstand soil-water distribution of various elements
to study how the diﬀerence of initial states can aﬀect
the soil-water distribution of elements. In this study,
the distribution experiments of various ions were conducted in both directions, that is, starting from dissolved ions (sorption experiments) and from ions insoil (leaching experiments). Multitracer method wasused in sorption experiments, which include many radioisotopes in a solution. On the other hand, leachingexperiments were conducted by ICP-MS for the stable
isotopes originally contained in the soil samples.
The soil was sampled from paddy ﬁeld in National
Institute of Agro-Environmental Science, Tsukuba,
Japan. For the leaching experiments, 20 g of air-driedsoil put into 50 ml styrene tube was mixed with watercontaining 0.010 M NaCl as supporting salt. In orderto observe dissolution of element to liquid phase invarious redox caused by soil condition, degree of water
saturation, pH, and temperature were varied. Similar
experiments were conducted for sorption experiments
using multitracer. Ionic strength of the solution added
to the soil was adjusted to 0.010 M by NaCl. The temperature was maintained at room temperature (293 –296 K).
For the sorption experiments, each element remaining in solution (RS ) was simply obtained from thepercentage of multitracer in water relative to the total amount introduced in the soil-water system. For
the leaching experiments, because of the presence ofvarious components as host phases for trace elements
in soil, fraction of elements in active phase for theleaching behavior was experimentally determined bysequential extraction,2,3) which can identify concentration in phases such as Mn oxide, Fe oxide, organic matters, carbonate, and exchangeable cations. We use thesum of concentration in all the phases in the extraction as “active element concentration”. For the leaching experiments, RL was deﬁned as the each element
in water relative to the active element concentration.
∗

122

Department of Earth and Planetary Systems Science,
Hiroshima University

It is expected that the element is reversible in terms of
the reaction with the active phase in soil-water system
when RS value is similar to RL value.
We have obtained the leaching and sorption behavior for Mn, Fe, Co, Zn, As, Rb, and Sr. The RS andRL values at various elapsed times were compared for
Co as an example accompanied with Eh variation depending on time (Fig. 1). Initial RS value for Co mustbe 100%, while initial RL must be 0%. As the elapsed
time increased, Eh value decreased due to the development of reducing condition by bacterial activities inthe soil. The RS value decreased until after 30 hours,
which turned into the increasing trend after that. The
RL values for Mn and Fe increased with time, showing the dissolution of Mn and Fe oxides during thedevelopment of the reducing condition. The increaseof RS value for Co is possibly due to the dissolutionof Mn and Fe oxides which can be host phases of considerable amount of Co in the soil. RL value for Co
monotonously increased with time as Eh decreases. Finally, RS and RL values have become similar for Co.
Considering the complex reactions in soil, it is interesting to observe the similarity for Co. This result
strongly suggests that the reaction of Co involved in
the active phase as deﬁned in this study is reversible,
the soil-water equilibrium of which can be attained
within about 600 hours.

Fig. 1. Dependence of RS , RL , and Eh values on the elapsed
time for Co. RS and RL : fraction remaining in the aqueous phase in the sorption and leaching experiments, respectively.

References
1) F. R. Siegel: in Environmental Geochemistry of Potentially Toxic Metals (Springer, Berlin, 2002), p. 32.
2) A. Tessier, P. G. C. Campbell, and M. Bisson: Anal.
Chem. 51, 844 (1979).
3) Y. Takahashi, R. Minamikawa, K. H. Hattori, K. Kurishima, N. Kihou, and K. Yuita: Environ. Sci. Technol.
38, 1038 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Multitracer technique for studies of uptake and eﬄux of traceelements in culture cell line
T. Suzuki,∗1 K. Ishibashi,∗1 S. Ohata,∗1 N. Sato,∗1 A. Yumoto,∗1 T. Togawa,∗1 K. Nishio,∗2
R. Hirunuma, H. Haba, S. Enomoto, and S. Tanabe∗1
The molecular mechanism of cisplatin resistance has
been revealed to be “multifunctional”; it decreases cisplatin accumulation, increases intracellular detoxiﬁcation and increases the DNA repair ability. A decreasein cisplatin accumulation was observed in non-small
cell lung cancer (NSCLC) cell lines resistant to cisplatin. There was a good correlation between the intracellular amount of platinum and sensitivity against
cisplatin. This result suggests that the intracellular accumulation of platinum is a major determinant of thecisplatin resistance, at least in NSCLC. Previously,
it was reported that cisplatin enters cells in an ATPdependent manner. Furthermore, it was reported that
cisplatin was removed by multidrug resistance proteins(MRPs) as a glutathione conjugate.1) On the other
hand, certain metals such as arsenite and cadmium
were removed from cells in the same manner. Therefore, the contribution of these transporters is important for metal detoxiﬁcation analysis. However, themolecular mechanisms of metal transport, such as theuptake and eﬄux of transporters were unclear.
In this study, to investigate the metal transportmechanisms including that of cisplatin, we determined
the amounts of various metals taken up by cisplatinresistant cell lines using a platinum tracer and multitracer. We modiﬁed the methods described by
Yanagiya et al.2) and used a human NSCLC cell line,
PC-9, and its cisplatin-resistant subline, PC-9/CDDP.
The cells were grown in RPMI1640 supplemented with
10% FBS. Pt tracer and radioactive multitracer (MT)solutions were obtained from the Au or Ag target irradiated in the RIKEN Ring Cyclotron, and used asphysiological saline solutions. Then, the Pt tracer or
MT solution was added to the cells in a serum-free
medium and incubated at 37 ◦ C. After incubation, thecells were separated from the medium and radioactivity was determined using a Ge detector.
As shown in Fig. 1, the accumulation of Pt in thecisplatin-resistant cell line was about 60% of that inparental cells. The amount of platinum uptake showing atrend similar to that of cisplatin uptake is interesting.

∗1∗2

Fig. 1. Uptakes of platinum in lung cancer cell lines. The
cisplatin-resistant cell line (closed column) and parental
cell line (open column) were exposed to the Pt tracer
for 2 h.

Furthermore, we examined the time courses of uptake of certain metals in lung cancer cell lines using
MT.
Figure 2 shows the results for Be and Mn. Since
the uptake behaviors of these metals are diﬀerent, we
examined the eﬄux of metals in culture cell lines using
MT.

Fig. 2. Time courses of uptakes of Be and Mn in lungcancer cell lines. The cisplatin-resistant cell line andparental cell line were exposed to the multitracer for 1,
2, and 4 h.

References
1) T. Suzuki et al.: Curr. Drug Metab. 2, 363 (2001).
2) T. Yanagiya et al.: Life Sci. 65, PL177 (1999).

Department of Analytical Biochemistry, Meiji Pharmaceutical University
Project Ward, National Cancer Center Hospital

123

RIKEN Accel. Prog. Rep. 38 (2005)

Iterative image reconstruction method for GREI
S. Motomura, H. Takeichi, R. Hirunuma, K. Igarashi, H. Haba, S. Enomoto, A. Odahara,∗
Y. Gono, and Y. Yano
The present prototype of the γ-ray emission imaging (GREI) system is a Compton camera that includes a strip germanium telescope.1) For image reconstruction, we have implemented two-step methods.
The back-projection of a detected event is a cone surface that indicates the possible position of the γ-ray
source. In the ﬁrst step, an intermediate image, whichis called a simple back-projection (SBP) image, is constructed by simply accumulating the back-projections
over all detected events, using an algorithm analogous
to the cone-surface mapping algorithm.2) Here we assume that SBP images (ni ) are constructed by linear
mapping of source distribution images (λj ), that is:
pij λj ,
(1)
ni =
j

where pij , which is referred to as a point-spread function (PSF), is a matrix representation of the linear
mapping, and i, j = 1, . . . , N . In the second step, λj
is reconstructed by the inverse mapping of ni .
If the PSF is assumed to be shift invariant, λj can bereconstructed analytically. The matrix pij is diagonalized by Fourier transformation of both sides of Eq. (1),and then λj is obtained as follows:
λj =

nj
.
pjj

No additional ﬁltering is necessary for this calculation.
To evaluate the performance of the algorithm, some
images were reconstructed using a shift-invariant PSF,
and the resultant images were compared with the analytically reconstructed images. Figure 1 shows theresults of both the analytical and iterative reconstructions for a soybean sample administered with a multitracer solution that includes 140-kBq 59 Fe. The number of iterations was 1.0 × 104 . The spatial resolution
using the iterative algorithm was improved comparedwith that using the analytical algorithm. Moreover,a ripple-like artifact, which is observed on the background in Fig. 1 (b), was removed in Fig. 1 (d). The
diﬀerences in the results were considered to be causedby the incompleteness inherent in the ﬁlter functionused in the analytical algorithm. It is impossible tocreate a ﬁlter function that can remove the statisticalnoise components completely and preserve the signal
components perfectly. The iterative algorithm is freefrom the restrictions caused by the ﬁltering.

(2)

In most cases, the right side of Eq. (2) is multiplied byan additional ﬁlter function (wj ) to suppress statisticalnoise components:
λj =wj n j.
pjj(3)

In reality, the PSF varies depending on both i andj (shift variant). Thus we have implemented an iterative algorithm in which a shift-variant PSF can be(0)
incorporated. First, an initial image λj is obtainedby averaging the SBP image:
(0)

λj

N

=

1 
ni .
N i=1

(4)
(n+1)

Then the (n + 1)-th estimate (λj) is obtained from(n)
the n-th estimate (λj ) as follows:
(n+1)

λj

∗

124

(n)

= λj

+


i



ni −


j

(n)

References

λj pij pij .

Nishinippon Institute of Technology

Fig. 1. Reconstructed images of 59 Fe administered to a soybean sample. (a), (b): Using the analytical algorithm.
(c), (d): Using the iterative algorithm.

(5)1) S. Motomura and S. Enomoto: J. Clin. Exper. Med.
205, 884 (2003).
2) R. C. Rohe et al.: IEEE Trans. Nucl. Sci. 44, 2477
(1997).

RIKEN Accel. Prog. Rep. 38 (2005)

Fourier analysis of back-projected images obtained by GREI system
S. Motomura, H. Takeichi, S. Enomoto, Y. Gono, and Y. Yano
In the procedure of image reconstruction for γ-ray
emission imaging (GREI), a simple back-projection(SBP) image is constructed as an intermediate image.1) In order for the source distribution image to bereconstructed from the SBP image, the information of
the original source distribution must be preserved in
the SBP image. If an SBP image is constructed with
infinite statistics, it must have the perfect informationof the source distribution. Needless to say, SBP images
are actually constructed with finite statistics, thereby
containing some statistical noise.
We have investigated the relationship between thestatistics and the noise components in terms of Fourier
power spectral densities (FPSDs). Three SBP imagesof a point source, which was placed 69 mm from thecenter of the front detector, were constructed by aMonte Carlo simulation using a GEANT2) code withthe detected event counts of 1.0 × 104 , 5.0 × 104 , and
1.0 × 105 . The γ-ray energy was 1116 keV, which corresponds to the intrinsic γ-ray of 65 Zn. Figure 1 shows
the FPSDs for the SBP images. One can see in Fig. 1that the high-spatial-frequency components are dominated by the statistical noise because they are significantly dependent on the statistics. Figure 2 shows thereconstructed image with the detected event count of
1.0 × 105 , where the signal components are dominant
up to spatial frequencies of 0.13 mm−1 and 0.05 mm−1
in x- and z-directions, respectively. The full widths
at half maximum were 4 mm in the x-direction and
10 mm in the z-direction. This result suggests that aspatial resolution of (2fc )−1 is obtained when the signal components are dominant up to a spatial frequency
fc .
The FPSDs of the SBP images can be utilized for
optimization of the voxel dimensions. If the frequency
where the statistical noise components start being
dominant is chosen as the Nyquist frequency, the influence of the statistical noise can be reduced without

Fig. 2. Reconstructed image of the point source with thedetected event count of 1.0 ×105 . The voxel dimensions
were 1 mm × 1 mm × 1 mm.

losing the spatial resolution. An SBP image was constructed with the Nyquist frequencies of 0.20 mm−1
and 0.08 mm−1 for x- and z-directions, respectively.
Then the source image was reconstructed from the
SBP image (Fig. 3). The fluctuation in the background
was reduced and the contrast of the image was improved by the optimization without losing the spatial
resolution.

Fig. 3. Reconstructed image of the point source with thedetected event count of 1.0 ×105 . The voxel dimensions
were 2.5 mm × 2.5 mm × 6.25 mm.

References
Fig. 1. Fourier power spectral densities of the SBP images obtained by Monte Carlo simulations of the present
GREI system.

1) S. Motomura et al.: RIKEN Accel. Prog. Rep. 38, 124(2005).
2) GEANT: Detector Description and Simulation Tool
(CERN, Geneva, 1993).

125

RIKEN Accel. Prog. Rep. 38 (2005)

Motion correction method for γ-ray emission imaging (GREI)
H. Takeichi
In this article, a solutiona) to the problem of body
movement in biological imaging by γ-ray emission
imaging (GREI),1–3) and its characteristic advantage
are described.
An imaging dataset, or “movie,” is essentially a composite of the form and motion of objects. Without
constraints, it is not possible to separate them. Therefore, when information on form, or a “picture” in isolation is required, such as in emission tomography, thebody movement causes a problem. This is particularly prominent in high-resolution imaging. The most
simple and generic solution is to stabilize the body. In
diagnosis, breath holding or electrocardiograph (ECG)
gating are sometimes used. However, it is not easy forsome cases such as children. Solving the problem for
nonrigid parts of the body such as the heart is difﬁcult. In contrast, solving the problem for approximately rigid parts such as the head appears tractable,
by measuring the motion independently and “subtracting” it from the original composite measurement toobtain the form information.
There are three major conventional ways for biological motion measurement: mechanical, magnetic,
and optical. The mechanical method uses some sortof spring and strain gauge. This is cheap, but does notappear desirable considering the design, operation, andprecision. The magnetic method is to place the sample
in a magnetic ﬁeld, and measure the induced current ina coil that is attached to the sample. The measurement
is precise and the operation is not very diﬃcult. However, the design of the apparatus is diﬃcult, particularly when another noninvasive biochemical measurement is performed concurrently. The optical method
is to scan optical markers such as light emitting diodes
that are attached to the sample with a camera, andanalyze the image. The design and operation are easy.
However, because the available space and the viewing
angle are limited, when another noninvasive biochemical measurement is performed concurrently, it is noteasy to achieve a high precision stably.
Because GREI can measure signals from multiple radioactive isotopes (RIs), motion can be monitored byattaching a few point sources that emit γ rays of diﬀerent energies as references and measuring their positions
concurrently. At least two references are required toobtain the six degrees of freedom: three translations
and three rotations. More refrences are preferred for a
precise measurement. Although the idea is very simple, this method is easy in design and operation, andhas a high precision. Its three important characteristics are as follows.
a)126

An application has been made for a patent for this scheme(JP 2004-151935, A).

First of all, unlike the optical method, no additional
apparatus is required. Correction can be carried out
only by computation. In an actual measurement, theonly operation is to attach a few point sources to thesample. The data are acquired without any additional
operations. The reference point sources can be placedat any location, as long as they are within the ﬁeld ofview of the imaging apparatus.
Second, because the reference is an isolated point
source, the data processing is trivial. The motion canbe estimated for each decay event in the list-mode databy forming a simple back projection (SBP) of the reference point sources and ﬁnding the peak in the SBP
from the list-mode data around the time point of eachdecay event. Because the data processing is trivial, it isalso easy to detect an inappropriate setting or absenceof the reference by evaluating the statistical propertiesof the reference data.
Third and ﬁnally, because the main measurement
apparatus itself is used for motion monitoring, whenthe measurement performance, such as the spatiotemporal resolution, of the main apparatus is improved,
unlike the optical system, no corresponding additional
improvement is required to the “motion measurement
apparatus.” A nearly identical scheme can be used at
the improved performance without modiﬁcation.
These characteristics mean that the method is inexpensive and practical, considering its beneﬁt, adding
some value in an application of GREI to nuclear
medicine, which is described elsewhere in this volume.
However, the following problems need to be considered.
First, the reference point sources need to have low activity if this technique is applied in nuclear medicine,
because they will be in close contact with the patient.
Second, the apparatus needs to be able to acquire data
suﬃciently fast so that both the reference signal andthe target signal are measured. Because the actual implementation of this scheme is in progress, the severityof these and other problems cannot be described at
this moment.
One implication of this scheme is that GREI can beused not only for the imaging apparatus, but also forthe motion measurement, or “tracking” apparatus, inradiation therapy, for example.
References
1) Y. F. Yang et al.: IEEE Trans. Nucl. Sci. 48, 656 (2001).
2) Y. F. Yang et al.: Nucl. Instrum. Methods Phys. Res.
A 482, 806 (2002).
3) S. Motomura et al.: Proc. IEEE Nuclear Science Symp.
and Medical Imaging Conf. (NSS-MIC), Rome, Italy,
2004-10 (IEEE Nuclear & Plasma Sciences Society,2005), in press.

RIKEN Accel. Prog. Rep. 38 (2005)

Current issues on application of γ-ray emission imaging GREI in
nuclear medicine
H. Takeichi and S. Motomura
In this article, important problems of the nuclear
medicine apparatus, solutions to overcome these issuesby γ-ray emission imaging (GREI), and the remaining
problems shall be brieﬂy summarized.
Nuclear medicine consists mainly of diagnosis andtreatment. In diagnosis, scintigraphy, single photon emission computed tomography (SPECT), andpositron emission tomography (PET) are commonly
used. By SPECT, the distribution of the tracer radioactive isotope (RI) is imaged using a scintillation
detector and a mechanical collimator. By PET, thedistribution of the tracer RI is imaged using a scintillator and a coincidence detector. The imaging performance is determined mainly by the detection schemeand the image reconstruction method. Various typesof scintillator of various sensitivities and decay times
are used. For image reconstruction, analytical ﬁltered
back projection (FBP) used to be frequently applied.
However, with the increasing computational power ofcomputers, more accurate iterative methods, such as
maximum-likelihood expectation maximization (MLEM) and its fast variation ordered subset expectation maximization (OSEM), are used more frequently
nowadays.
Scatter and absorption in the body largely inﬂuence
the image quality. Irrespective of the source of thephoton, γ rays emitted from the body are scattered inside the body. Because the scattered γ rays no longer
convey the accurate energy and position information,
they blur the image, which is observed when the energy window is not narrow. When the energy loss isgreat or complete and the γ ray is not in the energy
window, the γ ray is not observed. Indeed, this is
one of the reasons for the large dose in diagnostic nuclear medicine. In the case of PET, because the paired
annihilation γ rays “penetrate” the body, just like atransmission computed tomography (TCT), the activity detected for each pair of opposing detectors is independent of the position of the source along the lineof response. Therefore, it is possible to correct for theattenuation accurately by a transmission scan using aknown source outside the body to obtain the attenuation coeﬃcients, which is called the µ-map, prior to
the examination. In contrast, in the case of SPECT,
because the emission is unidirectional, it is by itself impossible to separate completely the actual activity ofthe source and the inﬂuence of the attenuation, which
depends on the structure and composition of the body,from the measurement. The uniformity of the structure and composition is often assumed, which is notquite correct. This is one of the main hindrances inquantitative SPECT measurement. Moreover, as thespatial resolution increases, body movements cause image blurring, as well. Even for a short examination
period, it is not easy to limit body movements on theorder of 100 or 10−1 mm.
By GREI,1–3) the distribution of the tracer RI isimaged using germanium (Ge) detectors and Compton
kinematics. It provides solutions to the problems asfollows.
By GREI, a broad range of γ rays is measured simultaneously and independently at a high energy resolution. The high energy resolution trivially eliminates
scatter artifacts only by setting up a narrow energy
window. Attenuation correction can be carried out by
two methods. One is to concurrently conduct the target emission imaging and reference transmission imaging using a planar source behind the body. Unlike thecommercially available CT/SPECT, the image registration is a negligible problem, as an identical apparatus collects the two datasets similarly at the sametime, with the only diﬀerence in the γ ray energy. The
other, more promising method is to measure γ raysof multiple energies from an identical nuclide. Because
the attenuation coeﬃcient depends on the γ ray energy
and the distributions should be identical, by simply
comparing the two independent measurements for twoenergies, an approximated µ-map is easily obtained.
The µ-map is in complete alignment with the target
measurement in this case too, which is advantageous
in high-resolution imaging. To this end, 111 In appears
the best candidate, because it is commercially available
and emits 171 keV γ ray at 90% and 245 keV γ ray at
94%. The problem of body movements can be solved
similarly using the simultaneous multiple-nuclide measurement. This is described in another article in thisvolume.
By SPECT the γ ray emitted from the nucleus ismeasured, while by PET the annihilation γ ray originating from the emitted positron is measured. Representative nuclides used for diagnostic imaging are
99m
Tc and 123 I for SPECT, and 18 F and 11 C for PET.
They are short-lived, reducing the time required for examination. The SPECT nuclides generally emit only
low-energy γ rays, reducing the biological eﬀects of radiation. The SPECT nuclides are often derived fromgenerators, while the PET nuclides are normally generated from medicinal cyclotrons. By GREI, both typesof nuclides, such as 18 F and 99m Tc or 123 I, which canlabel various substances, could be measured simultaneously, independently, and at a high spatial resolution
in alignment.

127

Unfortunately, the current implementation of
GREI3) is not complete. The problem of image reconstruction, more speciﬁcally, the problem of positiondependent response function needs to be solved. Eﬃciency, spatial resolution, and the choice and arrangement of the detectors may have some room for improvements.

128

References
1) Y. F. Yang et al.: IEEE Trans. Nucl. Sci. 48, 656 (2001).
2) Y. F. Yang et al.: Nucl. Instrum. Methods Phys. Res.
A 482, 806 (2002).
3) S. Motomura et al.: Proc. IEEE Nuclear Science Symp.
and Medical Imaging Conf. (NSS-MIC), Rome, Italy,
2004-10 (IEEE Nuclear & Plasma Sciences Society,2005), in press.

RIKEN Accel. Prog. Rep. 38 (2005)

Response of DNA repair proteins to heavy-ion-induced
DNA damages
M. Tomita, M. Izumi, T. Tsukada, N. Fukunishi, H. Ryuto, and Y. Yano
Ionizing radiation is known to induce DNA doublestrand breaks (DSBs), which are the most serious formof DNA damage. If not repaired eﬃciently, DSBs cause
cell death, chromosome translocations and genomic instability. Accelerated heavy ions with a high linear
energy transfer (LET) can induce complex clustered
DNA damages producing two or more DNA lesions
within a few helical turns. The complexity of clustered DNA damage shows strong LET dependence,
which makes it a good candidate as a prime determinant of a high biological eﬀectiveness.1) In mammalian cells, there are two major DSB repair pathways, namely, non homologous end-joining (NHEJ)
and homologous recombination (HR).2) The repair of
DSBs by NHEJ requires DNA-dependent protein kinase (DNA-PK), XRCC4, DNA ligase IV and Artemis.3) DNA-dependent protein kinase (DNA-PK) is
composed of a Ku-heterodimer and a catalytic subunit (DNA-PKcs) and is activated to bind to the ends
of double-stranded DNA. Activated DNA-PK phosphorylates the XRCC4 protein and itself in vivo.3,4)
Previously, we reported that the relative biologicaleﬀectiveness (RBE) of DNA-PKcs-defective human
M059J cells was signiﬁcantly lower than that of control M059K cells,5) suggesting that DNA-PK plays animportant role in the cellular response to heavy-ioninduced DSBs. In this study, we examined the activation and nuclear localization of DNA-PK after exposure to heavy ions.
To determine whether DNA-PK can recognize
heavy-ion-induced DSBs, we raised polyclonal phosphospeciﬁc antibodies recognizing DNA-PKcs at
Thr2638, which is a functionally relevant site in DNAPKcs.6) Figure 1 (A) shows the radiation-induced fociformation of phospho-DNA-PKcs on Thr2638 assessedby immunoﬂuorescence in human HeLa cells. We
observed discrete phospho-DNA-PKcs foci formed in
the cell nucleus irradiated with X rays. In addition,
phospho-DNA-PKcs formed larger foci after exposure
to C ions than to X rays. Figure 1 (B) shows the localization of phospho-DNA-PKcs on Thr2638 after exposure to Ar ions. HeLa cells were irradiated with Ar
ions, which intersect the cell nuclei as indicated by thearrow. The linear track pattern of phospho-DNA-PKcs
was clearly observed after Ar-ion irradiation. These results strongly suggest that DNA-PKcs is recruited in
the vicinity of multiple DSBs locally induced by heavy
ions to repair DSBs by NHEJ.
To further conﬁrm the activation of DNA-PK in response to heavy-ion-induced DSBs, we assessed DNAPK-dependent XRCC4 phosphorylation after irradi-Fig. 1. Spatial distribution of phosphorylated DNA-PKcs
on Thr2638 in HeLa cells after irradiation. (A) Cells
were fixed 30 min after exposure to 0 or 5 Gy of X
rays or C ions (80 keV/µm), and then analyzed by immmunofluorescence. (B) Cells were fixed 30 min after
exposure to 0.2 Gy of Ar ions (310 keV/µm), and thenanalyzed by immunofluorescence. Irradiation was performed such that the rays pass through the cell nucleus,
as indicated by the arrow. Bar represents 10 µm.

ation. XRCC4 was phosphorylated 0.5–1 h after Xray irradiation, and then dephosphorylated within 3 h(Fig. 2). The phosphorylation level of XRCC4 after
heavy-ion irradiation was higher than that after Xray irradiation, according to LETs. The time courseof XRCC4 phosphorylation, however, showed no difference in radiation quality. A series of results obtained suggests that DNA-PK recognizes the inductionof clustered DSBs by heavy ions, and phosphorylates
its substrates eﬃciently.

Fig. 2. Phosphorylation of XRCC4 in HeLa cells irradiated with 30 Gy of X rays, C (80 keV/µm) or Ar ions
(310 keV/µm). Cells were harvested at the indicatedtimes after irradiation, then assessed by immunoblotting. Slower migrating (upper) bands reflect phosphorylated form.4)

References
1) D. T. Goodhead: J. Radiat. Res. 40, Suppl. 1 (1998).
2) K. K. Khanna and S. P. Jackson: Nat. Genet. 27, 247(2001).
3) S. P. Lees-Miller and K. Meek: Biochimie 85, 1161
(2003).
4) Y. Matsumoto et al.: FEBS Lett. 478, 67 (2000).
5) M. Tomita et al.: RIKEN Accel. Prog. Rep. 37, 145(2004).
6) Q. Ding et al.: Mol. Cell. Biol. 23, 5836 (2003).

129

RIKEN Accel. Prog. Rep. 38 (2005)

Eﬀect of heavy-ion beam irradiation on mutation induction in
Arabidopsis thaliana (II)H. Saito, Y. Y. Yamamoto, T. Matsuyama, N. Fukunishi, H. Ryuto, T. Abe, and S. Yoshida
To achieve an eﬀective mutagenesis of arabidopsis (Arabidopsis thaliana), we examined the eﬀect ofheavy-ion beam irradiation on mutation induction. In
a previous paper, we reported that although the frequencies of albino plants were signiﬁcantly diﬀerent between irradiations using C and Ne with diﬀerent linear
energy transfers (LETs), these ions with similar LETs
provided similar frequencies of albino plants.1) In thepresent report, therefore, we examined the eﬀect of theseveral ions with similar LET on mutation inductionin arabidopsis.
Dry seeds of arabidopsis ecotype Columbia were prepared for irradiation treatments as in our previous
report.1) Seeds were irradiated with 12 C, 14 N, 20 Ne,
40
Ar and 56 Fe ions in a dose range of 10 to 550 Gy.
These ions were accelerated up to 135, 135, 135, 95 and90 MeV/nucleon, and their LETs were ca. 23, 30, 61,
280 and 640 keV/µm, respectively. To determine theeﬀects of LETs of heavy ions on mutation induction,
the LETs of C, N, Ne and Ar ion beams were controlled
to ca. 30, 61 and 280 keV/µm, 61 and 280 keV/µm,
280 keV/µm and 640 keV/µm, respectively, after passing through a set of absorbers in the range shifter.
All LETs were calculated behind plant materials. The
germination and culture of at least 150 M1 seeds werecarried out by the same method as in our previous report.1) Flowering rate (FR; number of ﬂowering plants
per total number of incubated M1 seeds) was determined one month after the transfer to soils in thepresent study.
In the control seeds without irradiation, the germination rate was more than 97% and all seedlings ﬂowered until one month after transfer to soil. Germination was not aﬀected by the irradiations with any
ions at the doses tested. The eﬀect of heavy-ion beamirradiations on FR is shown in Fig. 1. Without the130

Fig. 1. Eﬀect of heavy-ion beams on ﬂowering rate in arabidopsis.

range shifter for each ion (open spots), FR curves weremarkedly diﬀerent according to the kinds of ion. Ar
ions were the most eﬀective in decreasing FR, only afew plants ﬂowered among the seeds irradiated at adose of 100 Gy. On the other hand, FR was not affected by irradiations with N ions up to 550 Gy. Whenthe LETs were controlled using the range shifter (close
spots), similar FRs were observed between the treatments with several ions at the same LETs. Investigations of mutation rate in the M2 generation, such asthat of frequency of albino plants, are in progress.
Reference
1) H. Saito et al.: RIKEN Accel. Prog. Rep. 37, 147(2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Establishment of Arabidopsis thaliana lines mutagenized by heavy
ion beam irradiation
Y. Y. Yamamoto, H. Saito, H. Ryuto, N. Fukunishi, T. Abe, and S. Yoshida
For plant mutagenesis by heavy ion beam irradiation, irradiated samples (M1 ) are usually grown for
the next generation (M2 ), and phenotypic screening
is performed at M2 . The growth step requires a longtime (months to years), large space, and considerable
labor. Sharing M2 resources can save such researchresources of plant researchers and breeders, thus, it
is desirable to establish common M2 populations, aslong as many users are expected. As the ﬁrst trial, we
have decided to prepare an M2 population of Arabidopsis thaliana. There are several reasons for choosing
Arabidopsis. Firstly, it is one of the most commonlyused plant species for plant genetics. Secondly, thegrowth of Arabidopsis does not require a large outdoor space in a ﬁeld; an in house growth facility is
suﬃcient. Thirdly, considering its small genome size,a relatively small population is suﬃcient for saturated
mutagenesis. Fourthly, the most eﬃcient beam conditions for Arabidopsis mutagenesis have already been
determined.1)
Consulting our previous report,1) we irradiated dry
seeds of Arabidopsis thaliana ecotype Columbia witha Ne10+ beam at a dose of 150 Gy. The irradiatedseeds were then grown for self-pollinated seeds. After harvesting, we grew seeds from 9 M1 plants as one
batch. We prepared around 700 M2 batches, representing 6,000 M1 plants. Because one M1 plant contains two germ line cells2) , one batch of the preparedM2 seeds displays 18 independent germ lines. Assuming a heterozygote mutation at M1 , representation of
5 homozygous siblings at M2 on average requires 360
seedlings per batch.
There are several long hypocotyl mutant loci thathave been identiﬁed by extensive genetic studies, andamong them, hy1, hy2, and hy3 3) show signiﬁcantly
long hypocotyls when grown under white light. Examination of the appearance rate of these hy-type mutantsin the Ne-beam-irradiated M2 population, we found
4 independent mutant lines out of 200 M2 batches(Table 1). This rough estimation suggests that 150
batches corresponding to 3,000 germ lines provide one
mutant allele for each locus. According to this estimation, the prepared population of 700 batches would
provide 4 to 5 alleles per locus. Further analysis would
provide more precise information on the quality of our
Arabidopsis M2 population.
References
1) H. Saito, T. Matsuyama, Y. Y. Yamamoto, T. Abe, andS. Yoshida: RIKEN Accel. Prog. Rep. 37, 147 (2004).
2) G. P. Rédei and C. Koncz: in Methods in Arabidopsis
Research, edited by C. Koncz, N.-H. Chua, and J. Schell(World Scientiﬁc, Singapore, 1992), p.16.
3) M. Koornneef, E. Rolﬀ, and C. J. P. Spruitt: Z.
Pﬂanzenphysiol. 100, 147 (1980).

Table 1. Characteristics of the Arabidopsis M2 population.
PhenotypeNo. of screened No. of mutants Corresponding loci in thebatches
Arabidopsis genome
hy §1
200
4§2
3§3
albino200
41
unknown§1
Signiﬁcantly long hypocotyl phenotype under white light. §2 Identity of thegenetic loci is not determined. §3 hy1, hy2, and hy3.

131

RIKEN Accel. Prog. Rep. 38 (2005)

Chlorophyll-deficient mutants of rice induced by C-ion irradiation
T. Abe, Y. Hayashi, H. Saito, H. Takehisa,∗ Y. Miyazawa,∗ Y. Y. Yamamoto, H. Ryuto, N. Fukunishi,
T. Sato,∗ S. Yoshida, and T. Kameya∗
High-LET radiation such as heavy ions can be controlled to deposit high energy at precise positions. Recently, heavy-ion irradiation has become a new method
for mutation breeding to produce new cultivars. In
the case of Arabidopsis plants, one-half of the mutants
have small mutations such as base changes and smalldeletions involving a few bases and the other half large
DNA alterations such as inversions, translocations anddeletions.1) From these results, it can be concluded
that heavy ion irradiation-induced mutations show abroad spectrum and a high frequency. In a previous
paper we reported the eﬀect of heavy-ion beams on
rice.2) In this paper, we describe the mutational eﬀectof heavy ions on rice seeds for various soaking periods.
The rice seeds (Oryza sativa L. cv. Nippon bare)
were soaked for 1 to 3 days in water at 30◦ C without
light. The seeds that imbibed water were exposed to
C ions accelerated to 135 MeV/u by the RRC within adose range of 20 to 40 Gy. LET values of the C ions at
a dose of 20 Gy were adjusted using the absorbers from
22.6 to 60.3 keV/µm at the surface of the seeds. We
irradiated 150 seeds for each soaking period. After ir-

Table 1. Frequency of CDM in M2 plants induced by C-ion
irradiation.
Phenotype
Treatment
Soaking period (day)12
3Dose (Gy)
20
40
20
40
20 40
Fertile M1 line
128 128 129 102 129 128
Seed fertility (%)
85.3 85.3 86.0 68.0 86.0 85.3
Albina/Xanta
3
4
3
2
2
5
Chlorina
1
1
2
2
1
3
Striata0001
13Total CDM
4
5
5
5
4 11
CDM (%)
3.1 3.9
3.9 4.9
3.1 8.6
Harvest of 2002

radiation, the seedlings were transplanted to the paddy
ﬁeld. M2 seeds were harvested separately from each M1
plant approximately 6 months after irradiation. Then
seed fertility was investigated. M2 seeds were sown on
seedbeds, and grown in a greenhouse at 30◦ C for 11 hrs(daytime) and at 25◦ C for 13 hrs (night). One month
later, chlorophyll-deﬁcient mutants (CDM) were observed.
Thirty-four M2 progenies of 744 treated lines (Table 1) and 14 M2 progenies of 376 treated lines (Table 2) were segregated into green plants and CDM:
albina (albino); xanta (yellow leaves) chlorina (palegreen leaves); and striata (striped leaves) phenotypes.
Mutation rates at 40 Gy irradiation were higher thanthose at 20 Gy irradiation for every soaking period.
The optimal of CDM induction was obtained for irradiation at 40 Gy for seeds soaked for 3 days. HighLET irradiation caused a decrease in seed fertility(Tabel 2). There is no diﬀerence in mutation rate
at LET values of 22.6, 37.4 and 48.0 keV/µm. However, the percentages of fertile grains/panicle at LET
values of 37.4 and 48.0 keV/µm decreased comparedwith those at 22.6 keV/µm. The rice plant is one of
the most important food cereals. The sequencing of
the rice genome has been completed, and the genome
organization of cereals appears to be very highly conserved; rice, wheat, maize, sorghum, millet and othercereals exhibit a high degree of synteny. Therefore,
new mutants of rice induced by ion-beam irradiation
could be important genetic resources for research inplant functional genomics.
References
1) A. Tanaka: Gamma Field Simposia 39, 19 (1999).
2) T. Abe, T. Matsuyama, S. Sekido, I. Yamaguchi, S.
Yoshida, and T. Kameya: J. Radiat. Res. 43, S157
(2002).

Table 2. Frequency of CDM induced by C-ion irradiation at the dose of 20 Gy.
Phenotype
LET (keV/µm)
Fertile M1 line
Seed fertility (%)
Fertile grains/panicle (%)
Albina/Xanta
Chlorina
Striata
Total CDM
CDM (%)
Harvest of 2003
∗

132

22.6
119
79.3
73.2 ± 2.0
0
3
3
6
5.0

Graduate School of Life Sciences, Tohoku University

29.9
89
59.3
77.5 ± 2.4
1
0
0
1
1.1

37.4
81
54.0
65.3 ± 3.2
3
0
1
4
4.9

48.0
65
43.3
65.3 ± 3.6
1
0
2
3
4.6

60.3
22
14.7
45.2 ± 8.1
0
0
0
0
0

RIKEN Accel. Prog. Rep. 38 (2005)

Biological eﬀects of heavy-ion-beam irradiation on turfgrass
K. Watanabe,∗ C. Suzuki,∗ Y. Y. Yamamoto, T. Abe, S. Yoshida, and K. Yoneyama∗
One of the turfgrass groups, bentgrass (Agrostisspp.), is utilized at golf courses, football grounds, andracecourses. There are major diseases of the bentgrass,such as dollar spot disease and brown patch disease.
Although there are established methods of suppressing these diseases, these methods lead to pollution of
the environment. Therefore, the development of thedisease-resistant varieties is desirable. In order to establish procedures for mutation breeding of bentgrass,
we examined the biological eﬀects of heavy-ion-beamirradiation on it.
Dry seeds of bentgrass and wet seeds imbibed for
24 h were subjected to irradiation, and the eﬀects
of ion species as well as the dose response was observed. The energies of the ion beam were 135,
135, and 95 MeV/nucleon, and LET were 23, 63, and240 keV/µm for 12 C6+ , 20 Ne10+ , and 40 Ar17+ , respectively. The eﬀect of each ion beam was observed 30
days after the irradiation by measuring survival rates(Fig. 1) and plant heights (data not shown). As summarized in Fig. 1, the imbibed seeds showed more sensitivity to the irradiation than the dry seeds. The orderof the eﬀectiveness of the ion species is Ar, Ne, and C,
which is consistent with our previous result (1). Dose
responses of the survival rate and the growth index
were found to be similar (Fig. 1, data not shown).
Appearance rates of visibly recognizable mutants at
the M1 generation were also measured. Table 1 shows
the mutation rates by irradiating the imbibed seeds.

Table 1. Mutation rates of M1 plants.
Mutant§2
Ion
Dose Germina§1
Shrunken Striped
species (Gy) tion
leavesleaves
12

20

40

Total
mutant§3
(%)

C

0
20
25
30
35
40

80
60
56
66
56
37

0
0
2
1
0
3

0
0
0
0
0
1

0 (0)
0 (0)
2 (3.8)1 (1.8)0 (0)4 (10.7)

Ne

0
20
25
30
35
40

80
77
63
59
30
10

0
3
2
5
2
2

0
0
0
1
0
0

0 (0)
3 (3.9)2 (3.2)6 (10.2)2 (6.7)
2 (20.0)

Ar

0
1
5
10
15
20
30

71
66
68
58
11
0
0

0
0
0
2
1
0
0

0
0
0
0
0
0
0

0 (0)
0 (0)
0 (0)
2 (3.4)1 (9.1)
0 (0)
0 (0)

The results of wet seed irradiation are shown. §1 Numberof germinated seeds out of 100 irradiated seeds. §2 The
phenotype was examined 45 days after irradiation. §3 Sumof the shrunken and striped mutants. Mutation rates indicated in the parenthesis are frequency of mutants per
germinated seed.

As shown in the table, the range of doses from 20 to
40 Gy for C and Ne beams was found to be suﬃcientto generate mutants. However, the irradiation of C
and Ne beams to the dry seeds with the dose from 80
to 160 Gy did not give so high mutation rate as that
activated when irradiating for the wet seeds. Therefore, it might be necessary to examine higher dosesof irradiation for the dry seeds. The obtained data,summarized in Fig. 1 and Table 1, will be utilized foreﬀective mutagenesis of bentgrass on a large scale.
Fig. 1. Eﬀects of C6+ (diamond), Ne10+ (circle), and Ar17+(triangle) ion irradiations on survival rate. Solid anddotted lines show results of dry and imbibed seeds, respectively.

∗

Reference
1) H. Saito, T. Matsuyama, Y. Y. Yamamoto, T. Abe, andS. Yoshida: RIKEN Accel. Prog. Rep. 37, 147 (2004).

Meiji University

133

RIKEN Accel. Prog. Rep. 38 (2005)

Isolation of heavy-ion induced mutants of sweet pepper
I. Honda,∗ K. Kikuchi,∗ T. Abe, H. Saito, H. Ryuto, N. Fukunishi, and S. Yoshida
Mutant plants are very powerful tools to not only
clarify the physiological mechanisms of plants but also
develop new plant varieties in practical breeding programs. Many methods such as γ-ray irradiation, fastneutron bombardment and chemical treatments havelong been studied, developed, and utilized to induce
mutation. Recently, heavy-ion irradiation (HII) of
plants has been frequently utilized as a method to induce mutations in plants. Abe1) and Tanaka2) extensively applied HII technology to various plant species
and reported that mutation rates after HII were higher
than those after γ-ray irradiation. Various mutantions
induced by HII have already been reported in crops aswell as in ornamental plants, however, those in vegetable plants are still limited. In this study, we attempted to isolate HII mutants of sweet pepper (Capsicum annuum L.).
Dry seeds of sweet pepper (cv. California Wonder,
Takii Seed Inc.) were irradiated using 12 C- and 20 Neion beams (135 MeV/u) at a dose range from 1 to
300 Gy. The eﬀects of HII on the germination andgrowth of young seedlings were examined under normal cultivation conditions in soil. As shown in Fig. 1,
seeds irradiated with both the heavy ions at less than
10 Gy grew well, but their growth was severely inhibited after irradiation above 100 Gy. We selected seeds
irradiated with both the heavy ions at 10 Gy as suitable for isolating HII mutants. Their young plants weretransplanted into a plastic pot containing a commercial
soil mixture, and then cultivated in a greenhouse.
Among 108, 10-Gy 20 Ne-ion-irradiated plants, wefound two plants, the height of one of which was signiﬁcantly lower and that of the other one was slightly
lower than the others, and one plant whose ovary andpericarp of young fruits were yellow. These three lines

were putative HII mutants, and they were temporarily named D, SD, and Y mutants, respectively. Theirseeds were collected and the inheritances of those phenotypes in their progenies were examined. As shownin Fig. 2, the heights of all the progenies of the D mutant was signiﬁcantly lower and those of the SD mutant
were slightly lower than those of the untreated plants.
The phenotypes in terms of the heights of progenies of
either mutant were not segregated. All the progeniesof the Y mutant showed the viridis (yellow) phenotype
even in their leaves, ovary and young pericarp and thisphenotype was also not segregated. The viridis phenotype of the Y mutant progenies were not signiﬁcantearly in spring, but clear in summer, suggesting thatthe expression of those phenotypes may be aﬀected according to temperature or day length.
These results suggest that D, SD and Y are homozygous mutants induced by HII. Reciprocal crossings
between these mutants and wild-type plants were conducted to conﬁrm and clarify that the mutational event
occurred genetically. Physiological studies to clarify
the mechanism of the expression of phenotypes is also
necessary. In addition, seeds were obtained from 166
12
C- and 105 20 Ne-ion- irradiated plants. These seedstocks are useful for the isolation of other HII mutantsof sweet pepper in future studies. These results may
demonstrate that HII is also eﬀective for the inductionof mutation of sweet pepper, an economically important vegetable.

Fig. 2. Frequency distribution of heights of progenies of two
putative HII dwarf mutants (D and SD). The heights
are expressed as the heights of ﬁrst ﬂower. Open andclosed bars indicate the frequencies of the heights of D
and SD mutant progenies, respectively, and shaded bars
indicate those of the control (untreated) plants.

Fig. 1. Eﬀects of heavy-ion irradiation on early growth ofsweet pepper. Open and closed bars indicate the effects of 12 C- and 20 Ne-ion beam irradiation, respectively. Shaded bar indicates control (untreated).
∗134

National Institute of Vegetable and Tea Science

References
1) T. Abe: Breed. Res. 5 Suppl. 2, 58 (2003).
2) A. Tanaka: Breed. Res. 5 Suppl. 2, 50 (2003).

RIKEN Accel. Prog. Rep. 38 (2005)

Eﬀects of heavy-ion beam irradiation on in vitro shootsof Japanese pear ‘Nansui’
K. Osawa,∗1 I. Maruta,∗1 T. Abe, S. Tsunoda,∗1 and H. Yamanishi∗2‘Nansui’ is one of the leading Japanese pear (Phyrus
serotina Rehd.) cultivars in Nagano prefecture, although it is known to be susceptible to black spot disease. The disease caused by the Japanese pear pathotype Alternaria alternata is the most serious disease toaﬄict ‘Nansui.’ The pears susceptibility is controlled
by a single dominant gene.1) Mutants resistant to black
spot disease, induced by using gamma-ray irradiation,
have been sought after for a long time. Recently, someresistant mutants have been developed as new cultivars such as ‘Gold Nijisseiki’, ‘Osa Goldd’, ‘Kotobuki
Shinsui.’1) Therefore, a resistant mutant is desirablefor ‘Nansui.’ A combination of two techniques, heavyion beam irradiation and tissue culture, are expected
to induce a high mutation frequency. In this study, weinvestigated the eﬀects of two kinds of heavy-ion beamirradiation on in vitro shoots of ‘Nansui’ and found adose that allowed the shoots to survive and induced
the black-spot-disease-resistance mutation.
In vitro-grown shoots were irradiated. Shoot tips
were cut into 15-mm-long sections and placed on theshoot regeneration medium (MS medium with 1 mg/l
BA and 8 g/l agar). Twenty-one to twenty-ﬁve shoottips were placed in a plastic petri dish (9 cm in diameter). After 1 to 7 days of incubation, the shoot tips
were irradiated with 12 C6+ ions (135 MeV/nucleon,
22.6 keV/µm) in a dose range from 5 to 100 Gy or
20
Ne10+ ions (135 MeV/nucleon, 63.0 keV/µm) in adose range from 5 to 50 Gy. After irradiation, theshoots were transplanted onto a fresh medium andplaced in a plant box. Eight weeks after the culture,
the number of surviving and regenerating shoots werecounted and shoot growth was measured.
The survival rate, shoot growth, and number of regenerating shoots decreased with the increase in dosein both C-ion and Ne-ion irradiation. The survivalrate, growth and number of regenerating shoots decreased markedly at 15–25 Gy of C ions and 5–10 Gyof Ne ions (Table 1, Fig. 1, Fig. 2). The extent ofshoot growth and number of regenerating shoots were
suppressed by irradiation at doses higher than 25 Gy.
The Ne-ion beam had a stronger eﬀect than the C-ion
beam. The diﬀerence in the eﬀect is thought to be because LET (linear energy transfer) of Ne ions is higher
than that of C ions. The values of LD50 for the in vitro
shoots were found to be 15–20 Gy of the C ions and 5–
10 Gy of the Ne ions. LD50 values of shoot tips weresimilar to those of dormant scions.2) No variegated-leaf∗1∗2

Nagano Agricultural Research Center
Nagano Vegetable and Ornamental Crops Experiment Station

Table 1. Eﬀects of C- and Ne-ion beam irradiation of invitro shoots of ‘Nansui’ on survival rate.
Ion
Dose replications Total Survival Survival(GY)
shoots shoots rate (%)
Control
0
1
11
11
100
5
3
63
38
60
10
4
84
76
90
15
6
138
88
64
C
20
4
96
27
28
25
8
180
37
21
50
7
149
27
18
75
3
65
11
17
100
3
53
3
6
5
3
62
42
68
10
3
62
23
37
Ne
15
3
75
5
7
20
3
75
0
0
25
6
138
4
3
50
1
21
1
5

Fig. 1. Growth of in vitro shoots of ‘Nansui’ irradiated with
C- and Ne-ion beams.

Fig. 2. Number of shoots regenerated after irradiation with
C- and Ne-ion beams.
∗ Number of newly regenerated shoots from irradiatedshoots.

mutants were observed after irradiation. The plantsthat initially had abnormally shaped leaves continued
to grow normally and later produced normal leaves.
Further investigation is required to determine the visible mutation rate following heavy-ion beam irradiationof fruit trees. Moreover further experiments should be
performed to select mutants resistant to black spot disease.
References
1) T. Yoshioka et al.: JARQ 33, 227 (1999).
2) Y. Ito et al.: RIKEN Accel. Prog. Rep. 37, 151 (2004).

135

RIKEN Accel. Prog. Rep. 38 (2005)

Development of male sterile mutant that lacks pollen-producing
ability by heavy-ion beam irradiation in pelargonium
M. Sugiyama,∗ T. Terakawa,∗ H. Saito, K. Sakamoto, Y. Hayashi, N. Fukunishi, H. Ryuto, and T. Abe
In breeding ornamental plants and ﬂowers, mutation breeding has been a useful method because it canchange the speciﬁc characteristics and shorten the period required for breeding new varieties. In particular,
the induction of mutation by heavy-ion beam irradiation has attracted increasing interest in plant breeding.1,2) In this study, we developed a mutant pelargonium that lacks pollen-producing ability by heavy-ion
beam irradiation.
The stem of pelargonium (Pelargonium tricolor ×
P. ovale ssp. ovale ‘Splendide’) cultivated by tissue
culture was cut into approximately 5 mm segments,
each carrying a single axillary bud. The stem segments
were placed on hormone-free 1/3 MS medium containing one-third-strength MS salts and irradiated with a
12
C ion beam (135 MeV/nucleon, LET 23 KeV/µm) at
doses of 2.5, 5, 10, 20 Gy. Fifty segments (= ﬁfty axillary buds) were irradiated in each experiment. The
irradiated samples were transplanted onto 1/3 MS
medium containing 0.05 µM naphthylacetic acid forplant elongation and rooting. Four months after the
initiation of culture, the rate of surviving stem segments whose axillary buds developed relative to thetotal number of irradiated stem segments was determined. Then, the plants that survived were grown ina greenhouse until ﬂowering.
The survival rates of the plant irradiated with aheavy-ion beam and the eﬀect of irradiation on thegrowth of shoots are shown in Table 1 and Fig. 1, respectively. The survival rate ranged from 74 to 80%.
The growth of the plant irradiated at 10 Gy and 20 Gy
was slightly inhibited. A mutant was obtained by irradiation at both 5 Gy and 20 Gy (Figs. 2 (b), (d)).
All the ﬂowers formed on the mutant irradiated at
5 Gy had atrophic anthers with no pollens. On theother hand, the mutant irradiated at 20 Gy formed not
only abnormal ﬂowers whose anther was atrophic withno pollens but also normal ones, which suggests the
chimerical nature of this mutant. These characteristics were stable for 2 years. In the mutant, characteristics other than the anther morphology were normal,

Fig. 1. Growth of pelargonium shoot irradiated withheavy-ion beam.
The growth was examined fourmonths after the irradiation.

Fig. 2. Flower mutant obtained by heavy-ion beam irradiation. (a) Wild type flower, (b) mutant flower whoseanther is atrophic, (c) wild-type anther with pollens and(d) mutant anther without pollens.

however, the diameter of its ﬂower was slightly smaller
than that of the wild type.
Plants that lack pollens do not discharge their gene
into natural environments via pollination. Recently,
pollen-mediated gene ﬂow from transgenic crops towild relatives has become an extremely important issue. A male sterile mutant that lacks pollen-producing
ability induced by heavy-ion beam irradiation should
be a useful material for producing transgenic plants
without the above problem. The development of malesterile mutants of other plants is in progress.
References
1) M. Hamatani et al.: RIKEN Accel. Prog. Rep. 34, 169(2001).
2) M. Okamura et al.: Nucl. Instrum. Methods Phys. Res.
B 206, 574 (2003).

Table 1. Survival rate of plant and occurrence of mutant with atrophic anthers devoid of pollens inpelargonium irradiated with heavy-ion beam.
Dose
Number ofSurvival rate Number of Frequency of(Gy)surviving plants(%)
mutants
mutants (%)
Control
32
74
0
0
2.5
32
74
0
0
5
40
80
2
5
10
39
78
0
0
20
40
80
1
2.5
∗

136

Hokko Chemical Industry Co., Ltd.

RIKEN Accel. Prog. Rep. 38 (2005)

Characterization of sterile verbena cultivars produced byheavy-ion beam irradiation
H. Saito, Y. Hayashi, K. Suzuki,∗ T. Kanaya,∗ N. Fukunishi, H. Ryuto, T. Abe, and S. YoshidaIn the previous report, sterile mutant lines of theverbena cultivar ‘Coral Pink’ (Verbena hybrida) of theTemari series (Suntory Flowers Ltd., Osaka, Japan)
have been successfully isolated from N-ion beamirradiated nodal cultures.1) Recently, the sterile mutant of ‘Sakura’ of the same series has also been produced by the same method. Among these mutants,
it was suggested by cross-pollination tests that sterile ‘Coral Pink’ produce few seeds due to exhibiting
self-incompatibility. However, the characterization ofsterile ‘Sakura’ and detailed data of the pollination
tests on these mutants have not yet been reported.
We report here the characteristics of sterility of thesemutants and seed set following controlled pollinations.
Fertile (FC) and sterile (SC) ‘Coral Pink’, and fertile (FS) and sterile (SS) ‘Sakura’ were used. Maturepollen grains harvested at anthesis were stained with
KI to examine pollen fertility. Controlled pollination
tests were carried out for examining ovule fertility withemasculated flowers and fresh pollen grains. To determine the behavior of pollen tubes in the pistil, pistils
with ovaries were collected at certain hours after selfing and pollen tubes stained with decolorized aniline
blue were observed under UV light of a fluorescencemicroscope.
The pollen fertility of SC was the same as thoseof FC, while there are no viable pollens in SS (Table 1). The seed setting after controlled pollination
tests is shown in Table 2. The seed set of SS wasnever observed in the self-pollinations and the reciprocal crossing, thus both male and female gametes werecompletely sterile. On the other hand, SC × FC andSC × FS produced seeds. Therefore, it was indicatedthat SC have fertile ovules. However, in the case of
self-pollinated SC, FC × SC and FS × SC, few flowers produced seeds. Pollen germination on stigma wasobserved in pistils of self-pollinated SC, and then almost all pollen tubes accumulated on the upper regionsof the ovary and ovule remained unfertilized (Fig. 1).
Self-pollen tubes that arrest within the ovary, describing late-acting self-incompatibility, have been reported
in teak (Tectonia grandis) belonging to the Verbenaceae.2) Results of this report may suggest that SC
exhibits self-incompatibility. Detailed characterizationand the genetic analysis of incompatible phenotype toclarify the mechanism of self-incompatibility in verbenas is in progress using FC, SC and wild verbena
species.

Table 1. Pollen fertility in original and mutant lines of V.
hybrida.
Lines
Fertile pollens (%)
FC
73.7 ± 5.0
SC70.0 ± 5.9
FS91.5 ± 1.6
SS0Pollen grains were stained with KI.
Table 2. Seed set following self- and cross-pollinations
with original and mutant lines of V. hybrida.
♀♂

FC

SC

FS

SS

FC 58/96§1(60.4)§2 1/109 (0.9) 54/102 (52.9) 0/98 (0)SC 50/107 (46.7)
1/156 (0.6) 75/121 (62.0) 0/87 (0)FS 62/101 (61.4)
2/114 (1.8) 71/123 (57.7) 0/120 (0)SS
0/98 (0)0/106 (0)0/115 (0)0/58 (0)§1: Number of flowers producing seeds/number of flowers pollinated.
§2: Percentage of flowers producing seeds.
∗

R&D Department, Suntory Flowers Ltd.

Fig. 1. Florescence micrographs of FC and SC pistils following self-pollinations. Pollen tubes show brilliant florescence. (A), (B) Germinating pollens on surface ofstigma 3 h after selfing. (C), (D) Pollen tube growth instyles and ovaries 12 h after selfing.

References
1) K. Suzuki et al.: RIKEN Accel. Prog. Rep. 35, 129(2002).
2) S. Tangmitcharoen and J. N. Owens: Ann. Bot. 80, 401(1997).

137

RIKEN Accel. Prog. Rep. 38 (2005)

Flower color mutation in spray-type chrysanthemum (Dendranthemagrandiflorum (Ramat.) Kitamura) induced by heavy-ion beamirradiation
K. Suzuki,∗ Y. Takatsu,∗ T. Gonai,∗ M. Nogi,∗ K. Sakamoto, N. Fukunishi, H. Ryuto,
H. Saito, T. Abe, S. Yoshida, and M. Kasumi∗
Developing a mutant series with diﬀerent ﬂower colors from the original variety is a useful strategy as it isthen possible to use the same cultivation practices as
the original. A spray-type chrysanthemum is one of the
major cut ﬂowers and the modiﬁcation of ﬂower color
is performed by mutation breeding. To induce mutations in chrysanthemum eﬀectively we investigated theeﬀect of heavy-ion beam irradiation on the regeneration of shoots from stem segments and revealed the halflethal dose (LD50 ) in 18 varieties.1) In this study, we
report the ﬂower-color mutation induced by heavy-ion
beam irradiation.
Stem segments were placed on a shoot regeneration
medium consisting of MS basal medium supplemented
with 2.0 mg/l IAA and 0.2 mg/l BA. Three to 7 days
after the culture stem segments were irradiated with
12
C ion beams (135 MeV/nucleon, LET 23 keV/µm) at
doses around LD50 . Regenerated shoots were taken outof stem segments and further studied for mutation inexperimental ﬁelds. Among the 18 varieties studied,ﬁve red-type varieties exhibited color mutation (Table 1). However, nine yellow type, three white type andone red-type varieties did not show any color change.
The nonirradiated regenerated plants did not exhibit
any mutations indicating the absence of somatic mutations and the induction of color mutation by heavy-ion
beam irradiation. The rate of color mutation induced
was from 0.6 to 25.0% in ﬁve varieties.
A wide spectrum of ﬂower color was exhibited by
the mutants derived from the purplish-pink variety‘Chiyo.’ Induced color mutants were classiﬁed into twogroups, a pink-red group and a yellow-orange group.
To reveal the types of pigment in petals, we extracted
pigments using acetone for carotenoid and 3.0% HCl
for anthocyanin. The pink-red group contained antho-

cyanin as well as the original petals. The yellow-orange
group accumulated both anthocyanin and carotenoid.
Similarly to ‘Chiyo,’ the color mutants derived from
‘Nonko,’ whose original petals contain anthocyanin,
were classiﬁed into two groups, a pink-red group containing anthocyanin and a red-orange group containing both anthocyanin and carotenoid (Fig. 1 (A)). The
color mutants of ‘Beachball,’ ‘Sakiko’ and ‘Tomoshibi,’
whose original petals contain anthocyanin, accumulated both anthocyanin and carotenoid and their colors
shifted to the yellow direction (Fig. 1 (B)).
The results obtained in this study revealed thatheavy-ion beam irradiation using our tissue-culture
system is excellent for the mutation breeding ofchrysanthemums. Further investigation is needed toevaluate ﬂower-color mutants for developing new varieties.

Table 1. Flower-color mutation induced by heavy-ion
beam irradiation.
Original flowercolor
Beachball Strong red purple
Chiyo
Purplish pink

Dose No. of Color mutation(Gy) plants Plants
(%)
7
44
2
4.5
0
67
0
0.0
10
57
8
14.0
20
5
1
20.0
Nonko
Deep red purple
3
327
2
0.6
7
8
2
25.0
SakikoDeep purplish pink 1
150
2
1.3
Tomoshibi Storong red purple
3
77
1
1.3
Variety∗138

Plant Biotechnology Institute, Ibaraki Agricultural Center

Fig. 1. Flower color analysis of the mutants derived fromfive varieties using spectrophotometer NF333 (Nippon
Denshoku). Mutants were grouped into two (A) categories and one (B) category. Black symbols indicate
original varieties.

Reference
1) K. Suzuki et al.: RIKEN Accel. Prog. Rep. 37, 152(2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Development of PHENIX silicon pixel detectors
in ALICE-RIKEN collaboration
J. M. Heuser, H. En’yo, K. Fujiwara,∗ H. Kano, H. Ohnishi, and A. Taketani
For the silicon vertex tracker upgrade of the
PHENIX experiment at RHIC,1,2) we develop and produce pixel detectors in collaboration with the ALICE
experiment at CERN. ALICE is the dedicated heavyion experiment presently under construction at theLarge Hadron Collider. We participate in the ongoingproduction and tests of pixel detectors for the ALICE
inner tracker,3) a detection system similar in design
and purpose to the planned PHENIX upgrade, andprepare the production of PHENIX specific pixel sensor modules based on the ALICE technology. We profit
from the expertise of more than ten years with the development and application of hybrid pixel detector systems at CERN, and promote the development and construction of two pixel detector layers for the silicon vertex tracker that will be installed in the PHENIX experiment for the eighth physics run at RHIC in 2007/2008.
The upgrade of PHENIX with a silicon vertex
tracker will enable the so far inaccessible direct measurement of heavy-quark production through precision vertex tracking with pixel, “strip-pixel” and “ministrip” detectors in a multi layer barrel and end-cap arrangement closely surrounding the interaction region.
The two internal barrel pixel detector layers are of particular importance. They resolve the high track densities in heavy-ion collisions due to their high spatial
resolution in two dimensions, and provide secondary
vertex detection capability in this environment.
The key components of the hybrid pixel detector
technology developed at CERN are the front-end readout chip and the interconnection technique between
the chip and the two-dimensionally segmented sensor.
The front-end chip ALICE1LHCb, produced in an intrinsically radiation-tolerant 0.25 µm CMOS technology, contains 256 × 32 pixels of 50 × 425 µm2 size. The
pixels provide a binary output reporting their charge
detection. The chip is read out at 10 MHz and presents
the pixels’ hit status in 256 32-bit words on a bus. Several chips can be chained to build larger detector areas.
For the PHENIX application, four chips aremounted on a sensor substrate of approximately
6 cm length (“ladder”), utilizing a cutting-edge industrial flip-chip process with a 20-µm-diameter solderball interconnection (“bump bond”) for every pixel(Fig. 1 (a)). Two ladders are combined into a module, the basic detector unit controlled and read out
individually (Fig. 1 (b)). Every of the 10 or 20 azimuthal sectors of the two barrels comprises two modules, mounted with their readout sides pointing in opposite directions (Fig. 1 (c)).
∗

Niigata University

Fig. 1. The pixel detector of the PHENIX silicon vertex
tracker comprises (a) 120 sensor ladders on (b) 60 modules, mounted in (c) the two internal barrel layers.

For the production of PHENIX ladders, we selected the good die from 8” ALICE1LHCb wafers with
86 chips each,4) utilizing a wafer probe station with a
specific test system. Simultaneously, the sensors were
fabricated on high-resistivity 6” wafers with nine sensor ladders each. We await the final processing steps
after the validation of the flip-chip tests presently performed for the ALICE experiment. The flip-chip assembly of the ladders is imminent and will be carriedout as part of the ALICE ladder production.
The eight chips of a module will be wire-bonded toa thin aluminum-Kapton bus running on top of thesensors. At 10 MHz, the highest clock frequency reliably applicable to the ALICE1LHCb chips, groupsof two chips must be read out in parallel to match the
PHENIX readout requirement of 40 (80) µs, four times
faster than in ALICE. A pixel bus with four parallel
data structures is presently under development,5) tobe read out in 50 µs with two custom-designed “pilot”
chips containing the ALICE data handling twice.6)
We have been contributing to the validation and application of this pixel detector technology in ALICE
test beam experiments and the fixed-target heavy-ion
experiment NA60 at the CERN-SPS.7)
References
1) J. M. Heuser: Proc. 6th Int. Workshop on Radiation Imaging Detectors (IWORID) 2004, Glasgow, UK,
2004-7, to be published in Nucl. Instrum Methods Phys.
Res. A.
2) A. Drees: J. Phys. G 30, S1109 (2004).
3) V. Manzari et al.: J. Phys. G 30, S1091 (2004).
4) K. Fujiwara et al.: RIKEN Accel. Prog. Rep. 38, 228(2005).
5) A. Taketani et al.: RIKEN Accel. Prog. Rep. 38, 233(2005).
6) H. Kano et al.: RIKEN Accel. Prog. Rep. 38, 237(2005).
7) P. Nilsson et al.: Nucl. Instrum. Methods Phys. Res. A
535, 424 (2004); H. Ohnishi and J. M. Heuser: RIKEN
Accel. Prog. Rep. 38, 76 (2005).

139

RIKEN Accel. Prog. Rep. 38 (2005)

Development of large-area two-dimensional
position-sensitive silicon detectors
R. Kanungo, H. Takeda, S. Terashima,∗1 Z. Li,∗2 W. Chen,∗2 Y. Matsuo, H. En’yo, and I. Tanihata∗3
In various applications, one must measure precisely
the position or location of an event of interest. Thus,
development of position-sensitive detectors has gained
considerable importance. An interesting usage of thistechnology in genomic science may be for testing thetwo-dimensional imaging of low-energy ions emitted
from cDNA chips and possibly also from a slice of acell. Imaging of elemental distributions with few tensof microns would be a signiﬁcant achievement.
For studies using radioactive ion beams in nuclear
physics, position-sensitive detectors ﬁnd immense usage in the detection of recoiled particles in scatteringexperiments. One of the most important studies on
this front is the measurement of density distribution.
Conventionally, proton elastic scattering has served
as one of the best tools for probing the matter density of a nucleus. In the case of unstable nuclei, such
scattering can be performed only in inverse kinematics,
where the proton is the target nucleus. This involves
detection of recoil protons with good energy and position resolution. This is necessary in order to distinguish the inelastic scattering. It is often desired thatsuch detectors should be placed in vacuum. The silicon
microstrip detectors are well suited for this purpose.
The necessary detection conditions require a position
resolution of ∼ 125 µm (one standard deviation) in thetheta-direction. A resolution of 2 mm in the azimuthal
direction was found to be suﬃcient for this purpose.
We report here the development of a twodimensional position-sensitive silicon detector. As an
initial step, the design was focussed on achieving thegoal of proton elastic scattering described above. A signiﬁcant feature of the detector is its large active areaof 50 mm×70 mm. The detector is a strip-pixel type,1)
which employs extraction of two-dimensional position
information from one side of the silicon sensor.
It consists of an X-Y array of 200 × 14 pixels. The
pixels are 5 mm long in the Y -direction and 250 µm
wide in the X-direction. Each pixel has two independent types of electrodes. Electrodes of one type are interconnected along the X (or Y ) direction. This results
in a readout like that from a double-sided strip detector, but from only one surface. Thus, the X-direction
has 200 readout pads while there are 14 readout pads
for the Y -direction.
The ﬁnal detector geometry involves building up acircular-arc array with the proton target at the cen∗1
∗2
∗3

140

Department of Physics, Kyoto University
Instrumentation Division, Brookhaven National Laboratory,
USA
Argonne National Laboratory, USA

ter. Thus, it was required to have both the X andY pads read out in the same direction. The detector
is shown in Fig. 1, which illustrates the readout pads.
The silicon sensor was fabricated at Brookhaven National Laboratory, USA.
Figure 2 shows the test measurement of the sensor
characteristics. The example is shown for probing aparticular pad in the Y -direction. The adjacent pads
were grounded for the test. The condition was not altered much when the adjacent pads remained in theﬂoating condition. The X-direction also shows a similar trend. The current-voltage characteristics show aslightly higher value of current. This may be due tothe increased surface area of the line electrodes for thislarge design of the sensor. A more complete view canbe obtained by observing the current after integrationof the pads with readout electronics.
The 200 pads in the X-direction are read out individually using the ‘VA hdr1’ chip from the IDEAS company. This chip is an integrated circuit which includes
a preampliﬁer, a shaper and a multiplexer. The drivercircuit of the chip is shown in Fig. 1. The digitizedsignal from the sensors through the chips will be processed through CAEN, V550A ADC. The sequencer
CAEN V551B is used for driving the VA chips. Aninterface circuit is used for coupling between the VME
units and the VA chip circuit and is shown in Fig. 3.
Further tests of the detectors are in progress.
The authors are thankful to Dr. J. Tojo and Dr. Y.
Goto for useful discussions. Mr. S. Shimizu is gratefully acknowledged for fabricating the readout circuits.
Thanks are due to Haraseiki Company, Kumamoto, forFig. 1. The silicon strip-pixel detector with the readout VA
chips and part of the associated driver circuit.

Fig. 3. View of the interface board used for coupling between the sensor readout and the VME units.

wirebonding of the sensors and chips. The help of Mr.
K. Fujishiro, Kindai-denshi-elc. Company for overall
integration of the detector is gratefully acknowledged.
Reference
1) Z. Li et al.: Nucl. Instrum. Methods Phys. Res. A 535,
404 (2004).
Fig. 2. The C-V (a) and I-V (b) characteristic curves measured for the detector.

141

RIKEN Accel. Prog. Rep. 38 (2005)

Application of ultrathin silicon detector in low energy nuclear
reaction measurement†
S. Nishimura, M. Kurata-Nishimura, J. J. He,∗1 H. Fujikawa,∗1 H. Yamaguchi,∗1 S. Kubono,∗1 Y. Tagishi,∗2
M. Yamaguchi,∗2 T. Teranishi,∗3 M. Kurokawa, T. Kishida, and T. Motobayashi
Recent progress in high-power accelerator facilities has enabled the study of nuclear reactionsin the low-energy frontier, which is essential toclarify the astrophysical nucleosynthesis that occurred in the early stages of the Big Bang aswell as the rapid-neutron capture process in supernovae explosions.
In this scenario, the path
4
He(t,γ)7 Li(n,γ)8 Li(α,n)11 B(n,γ)12 B(β,ν)12 C is a key
reaction ﬂow for explaining the synthesis of 12 C andheavy elements according to full network calculations.1)
8Li(α,n)11 B is recognized as an important reaction
for passing through the valley of A = 8 in nucleosynthesis. Various experiments in the past decade haveattempted to determine the reaction cross section of
8Li(α,n)11 B.2–5) However, the results do not seem to
be in qualitative agreement with each other. Moreover, the most interesting energy region of data below
1 MeV is missing due to the diﬃculties of particle identiﬁcation of low-energy 11 B ions from the backgroundparticles, which mainly consists of elastically scattered8
Li ions, and α particles as well as the decay productsof 8 Li.
A new experimental approach for exploring these
low-energy nuclear reactions using a monolithic silicon
telescope (MST) has been studied using the simulation code GEANT4.6) Our feasibility study indicatesthat the ultrathin silicon detector could be applied tothe measurements of the low-energy nuclear reaction
products as a novel technique. In this article, the performance of the MST will be reported using low-energy
11
B and 7 Li ions from an accelerator together with α
particles from a source (241 Am).
The primary beam of 11 B and 7 Li ions accelerated
up to 12 MeV by the Tsukuba TANDEM Accelerator
is ﬁrst degraded and scattered by a ∼3 µm Au foil.
The energies of ions are roughly adjusted by altering
the angle of the Au foils and chosen by adjusting thedownstream magnetic setting of a spectrometer (Q-DQ magnets) tilted at a 35 degree angle. Two diﬀerent
sizes of collimator with hole sizes of 3 and 10 mm φ areinstalled in front of the MST at the end of the spectrometer. A single MST consists of two 508-µm-thicksilicon detectors (E) assembled on a 14 pin IC socket.
In addition, ﬁve ultrathin silicon pads (∆E) of 1 µm
†
∗1
∗2
∗3

142

Condensed from the article in Phys. Rev. Lett. 85, 1827
(2000)
Center for Nuclear Study, University of Tokyo
University of Tsukuba
Kyushu University

thickness are arranged on the surface of each of the Elayers.7) Two signals from the ∆E and E layers provide the dE/dx and the total energy deposited by theincident ions, simultaneously. The size of each ∆E pad
is set to 3 × 4 mm2 to reduce the capacitance down to
2 nF in order to reduce the noise level with the use of astandard preampliﬁer. The signals from the preampliﬁers go to shaping ampliﬁers (ORTEC 641) for precise
pulse height measurements. Data is gathered using
a self-triggering mode on the MST, requiring a minimum energy deposit of above ∼100 keV in one of the∆E pads. Figure 1 shows the compiled scatter plot
between ∆E and E in arbitrary units for 11 B and 7 Li
ions. The ﬁgure was created by superimposing the datataken at diﬀerent magnetic settings of the spectrometer. The α particles data is also added using an 241 Am
source under the slow pressure control of air as an energy degrader. Our result suggests that the MST has
an excellent capability for identifying the low-energy
11
B from the 7 Li ions and α particles down to theenergy of 0.11 MeV/u, which is the lowest separationenergy of this detector as determined by the stopping
range of the incident 11 B ions within the ﬁrst ∆E layer.
The bands in the low ∆E region correspond to the hit
events on other pads. The incident angle dependence

Fig. 1. Correlation between the energy deposited in ∆E
and E layers by diﬀerent incident ions. The clear separation among the 11 B and 7 Li, and α particles in the
low-energy region evidences the excellent performanceof the MST for the 8 Li(α,n)11 B reaction measurement.

of the energy spectrum is also measured by changing
the angle of the MST with respect to the direction of
the incident particles. Our preliminary results show
possible channeling eﬀects of the incident ions in the∆E layer at the particular angle of the incident ions to
the MST around 0 degrees (perpendicular). This effect disappears within 2.5 degrees and shows up again
around 35∼40 degrees. Fortunately, this feature is expected to be negligible because our design of the MST
allocation and its kinematics in the gas target will result in fewer occurrences of these events.
We have tested one of the MST samples and conﬁrmed that is has adequate energy resolution andno evident crosstalk among the pads. The ﬁrst ex-

periment for the 8 Li(α,n)11 B reaction is scheduled in
March, 2005 at the CRIB.
References
1) M. Terasawa et al.: Astrophys. J. 562, 470 (2001).
2) X. Gu et al.: Phys. Lett. B 343, 31 (1995).
3) R. N. Boyd et al.: Phys. Rev. Lett. 68, 1283 (1992).
4) Y. Mizoi et al.: Phys. Rev. C 6206, 5801 (2000).
5) S. Cherubini et al.: Eur. Phys. J. A 20, 355 (2004).
6) M. Kurata-Nishimura et al.: RIKEN Accel. Prog. Rep.
37, 183 (2004).
7) A. Musumarra et al.: Nucl. Instum. Methods Phys. Res.
A 409, 414 (1998).

143

RIKEN Accel. Prog. Rep. 38 (2005)

Energy resolution of superconducting series junction detector forheavy ions
H. Sato, M. Kurakado, Y. Takizawa, S. Shiki, M. Ohno, S. Ariyoshi, H. M. Shimizu, K. Morita, K. Morimoto,
D. Kaji, and T. Akiyama∗
Superconducting tunnel junctions (STJs) as radiation detectors, particularly as photon detectors, havebeen developed by many groups, because STJs can realize photon detectors with good energy resolution. In
addition, STJs can detect high-energy heavy ions bystopping them in a substrate. In the case of direct
detection using a single junction, a large number ofquasi-particles are generated in superconducting layerof the STJ. As a result, the recombination probability of the quasi-particles becomes large and the pulse
height of output signal v.s. energy does not show good
linearity. This situation also occurs with conventional
semiconductor detectors for the detection of high energy particles. In contrast, when high-energy particles
hit a substrate, phonons are generated inside the substrate and diﬀuse.1,2) As a result, each single junction,
which is a component of a series-junction detector, detects part of the total deposited energy. For example, if
the series-junction detector consists of 10000 STJs andthe incident energy is 100 MeV, it is expected that eachsingle junction would detect 10 keV. Consequently, theseries-junction detector is expected to maintain its energy resolution and linearity up to several hundreds of
MeV.
We have been developing two sizes of series-junction
detector, one is the small type (6 mm × 6 mm chipsize)3,4) which achieves an energy resolution of 0.5%
at 5.49 MeV, and the other is the large type (12 mm
× 12 mm chip size). For the detection of high-energy
heavy ions, we select the large-type chip which has
a detection area of 8 mm × 8 mm because the total
number of single STJs in the series-array detectors islarge. An example of the series-junction detector isshown in Fig. 1. The structure of each single STJ
is Nb/Al/AlOx/Al/Nb and STJs are fabricated on asapphire substrate whose thickness is 0.4 mm. A single STJ is 110 µm in diameter. 288 single STJs areconnected in series and 3 series-arrays are connectedin parallel. Thus, 288 × 3 = 864 STJs are included
in one array and one series-junction detector consistsof 864 × 4 = 3456 STJs. The detection area of thedetector is surrounded by these four arrays.
An experiment was carried out for evaluating theenergy resolution and linearity of a series-junction detector at the GARIS beam line at the RIKEN linear
accelerator (RILAC). A cryostat was placed on the focal point of the GARIS beam line and an 40 Ar beamfrom RILAC (136 MeV, 152 MeV and 191 MeV) was
introduced to the cryostat through two Al thin ﬁlms∗

144

Department of Physics, Saitama University

Fig. 1. Chip of series-junction detector.

(100 nm in thickness) which act as thermal shields.
A series-junction detector was attached to a copper
plate which had a hole (8 mm × 8 mm) in its center.
The copper plate was mounted in the cryostat to becooled to 0.4 K (Fig. 2). Each array was connectedto the charge preampliﬁers independently. Only coincident signals from the four arrays were acquired astrue events. The accumulation of the sum of four signals from the arrays creates the energy spectrum of
40
Ar. However, the obtained pulse height of the signal depends on the detected position because of thenonuniformity of the character of the arrays and thediﬀerence in the phonon distribution in the substrate.
This position dependence of pulse height makes thepeak width broad if we simply sum all events. To pre-Fig. 2. Schematic view of cryostat.

Fig. 3. Projection of obtained pulse height (ADC channel).
(A) shows projection to x-axis and (B) shows projection
to y-axis. Data inside of two dashed lines were used foranalysis.

vent this eﬀect, a position correction method is applied
to our data to obtain energy resolution and peak position channel.5)
The energy resolution obtained with a 191 MeV 40 Ar
beam was calculated. From the two-dimensional scatter plot, the pulse height (sum of the signals from four
arrays) distribution was projected on the x-axis andy-axis (Fig. 3). The position dependence of the pulse
height was observed, as mentioned before. Thus, we
cut the obtained data into a region of 0.4 < x, y < 0.6
and the data in this region was analyzed. In order
to apply the position collection method, the detection
area was divided into 40 × 40 cells and the data of thecells which had events less than 10 counts were notused to reject inaccuracy. As a result, we obtained anenergy resolution of 4.2% (8.1 MeV) at full-width at
half-maximum (FWHM) (Fig. 4). On the other hand,from an analysis of all data in all region, an energy resolution of 4.9% was obtained. These values are comparable to that of conventional semiconductor detectors
and show that further improvement is necessary. So
we are now preparing a new design of chip to obtainbetter resolution.
We measured the energy spectra at three energies of40
Ar beam (136 MeV, 152 MeV and 191 MeV). A peakchannel was obtained by the same manner as describedabove for each spectrum. However, the energy peaks of

Fig. 4. Energy spectra obtained at beam energy of
191 MeV. (A) shows spectrum before applying position
correction and (B) shows after applying position correction. Energy resolution of 4.2% (8.1 MeV) at FWHM
was obtained.

136 MeV and 152 MeV were very broad and had a distorted shape. Therefore, the obtained peak channels of
136 MeV and 152 MeV were not reliable. We consider
that this does not come from detector properties but
rather from experimental error. Consequently, fromthis experiment, we cannot judge whether the seriesjunction detector is free from saturation of the pulse
height in the high-energy region. Further experiments
are needed to resolve this problem.
References
1) M. Kurakado, A. Matsumura, T. Takahashi, S. Itoh, R.
Katano, and Y. Isozumi: Proc. SPIE 1743, 351 (1992).
2) M. Kurakado, D. Ohsawa, R. Katano, S. Itoh, and Y.
Isozumi: Rev. Sci. Instrum. 68, 3685 (1997).
3) H. Sato, M. Kurakado, Y. Takizawa, S. Shiki, and H. M.
Shimizu: RIKEN Accel. Prog. Rep. 37, 157 (2004).
4) H. Sato, Y. Takizawa, S. Shiki, C. Otani, M. Kurakado,
and H. M. Shimizu: Nucl. Instrum. Methods Phys. Res.
A 520, 613 (2004).
5) M. Kurakado, S. Kamihirata, A. Kagamihata, K.
Hirota, H. Hashimoto, H. Sato, H. Hotchi, H. M.
Shimizu, and K. Taniguchi: Nucl. Instrum. Methods
Phys. Res. A 506, 134 (2003).

145

RIKEN Accel. Prog. Rep. 38 (2005)

Measurements of energy resolution and position dependence ofNaI(Tl) scintillators
H. Takeda, S. Terashima,∗ T. Murakami,∗ T. Ohnishi, H. Sakaguchi,∗ T. Suda, Y. Yasuda,∗ and J. Zenihiro∗
Proton and neutron density distributions in nuclei
provide fundamental information on nuclear physics.
For stable nuclei, we have succeeded in determining
neutron distributions from proton elastic scattering at
intermediate energies (200–400 MeV).1) It is suitable
to extract internal information on nuclei since the NN
cross section is minimum at such an energy region. The
RI beam from the RIBF will have the same energy,
thus we can use the beam to deduce nucleon density
distributions in unstable nuclei.
To perform proton elastic scattering from unstable
nuclei using the RI beam, we are constructing a recoiled particle detector system. An overview of thissystem is shown in Fig. 1. The system consists of twoparts. The ﬁrst part consists of a thin CH2 target, silicon microstrip detectors2) and Si(Li) detectors. The
second part consists of a windowless solid hydrogentarget,3) drift chambers and NaI(Tl) scintillation counters. In both parts, the scattering angles and energiesof the recoiled protons scattered by the RI beam in thetarget are measured to reconstruct the Q-value spectrum to separate elastic scattering events from inelastic
ones.
NaI(Tl) scintillation counters are prepared as highresolution calorimeters to measure the total energies
of recoiled particles. Each counter consists of a 50 ×
50 × 450 mm3 NaI(Tl) crystal, a 3 mm-thick aluminum
housing with Pyrex optical windows and photomultipliers. A 100 µm-thick entrance window with an areaof 46 × 432 mm2 can be found on one of the surfaces of
the aluminum housing.

We measured the energy resolutions and position dependences of the NaI(Tl) counters using a 12 MeV proton beam to ensure that they satisfy the speciﬁcations
required to achieve the desired resolution of the Qvalue spectrum. The measurements were performedat the Tandem Van de Graaﬀ Accelerator Laboratory,
Kyoto University. A schematic view of the experimental setup is shown in Fig. 2. The 12 MeV proton beam
was bombarded on Au target of ∼1 mg/cm2 thickness.
The scattered protons passed through a slit of 5 mm
width and were measured using the NaI(Tl) scintillator. The NaI(Tl) scintillator was placed on a movablestage to change the position of the incident protons.
The temperature of the NaI(Tl) scintillator was continuously monitored using a Pt resistance thermometer since the light output in the NaI(Tl) scintillator
changes with temperature. The ﬂuctuation in temperature was ±0.8◦ C throughout the measurements.
The measured energies are plotted as functions ofslit position in Fig. 3. The measured energies√are obtained by considering the geometric means ( L × R)of light outputs from the left and right photomultipliers
to reduce the position dependence due to the absorption in the propagation of light, and are normalized
to 12 MeV at the center position. Energy resolutions
are obtained by the Gaussian ﬁtting of the spectrumof the measured energies, which are 1–2% in FWHM.
This result is almost consistent with the rough estimate of the number of photoelectrons emitted fromthe photocathode of the photomultiplier when a lightcollection eﬃciency of 20% and a quantum eﬃciency ofthe photocathode of 20% are assumed. However, there
are certain unique position dependences in the measured energies as shown in Fig. 3. Such results might
be due to the uneven characteristics of thallium dop-

Fig. 1. Overview of the recoiled particle detector system.
∗

146

Department of Physics, Kyoto University

Fig. 2. Schematic view of experimental setup.

Fig. 3. Energy resolution and position dependence for each NaI(Tl) counter.

ing, entrance window thickness, reﬂectors inside thealuminum housing and NaI crystal itself.
Only the surface of the NaI(Tl) crystal was associated with the results here since the range of 12 MeV
protons in the NaI(Tl) crystal is less than 1 mm. Further tests with a high-energy beam are necessary to investigate the position dependence deep inside the crystals. A test experiment using a 65 MeV proton beam isunder preparation at the Research Center for Nuclear
Physics, Osaka University. The measurement of thetemperature dependence of light output is in progress.

References
1) H. Takeda et al.: AIP Conf. Proc. 610, 648 (2002);
AIP Conf. Proc. 675, 720 (2003); Proc. KyudaiRCNP Int. Mini-Symp. on Nuclear Many-Body andMedium Eﬀects in Nuclear Interactions and Reactions(MEDIUM2002), Fukuoka, 2002-10 (World Scientiﬁc,
Singapore, 2003), p. 269; S. Terashima et al.: RCNP
Ann. Rep. 2002, 43.
2) R. Kanungo et al.: RIKEN Accel. Prog. Rep. 38, 140(2005).
3) T. Ohnishi et al.: RIKEN Accel. Prog. Rep. 38, 150(2005).

147

RIKEN Accel. Prog. Rep. 38 (2005)

Calibration method for fast-neutron detector wallusing cosmic rays
J. Gibelin,∗1,∗2 N. Fukuda, Y. Kondo,∗3 K. Kurita,∗2 T. Motobayashi, T. Nakamura,∗3 and Y. Satou∗3
Neutron detector walls composed of multiple plastic scintillator rods play important roles in detecting
fast neutrons emitted from the breakup of neutron-richnuclei at intermediate or high incident energies.1–3) In
recent experiments at Riken,4,5) the energy and scattering angles of the resulting fragments and neutrons
were measured to deduce the excitation energy before
breakup, using the invariant mass method. Breakup
neutrons, with energies close to that of the beam (fewtens of MeV) were detected using a neutron detector
wall schematically represented in Fig. 1.
The energy of the neutrons was deduced from thetime-of-ﬂight from target (TOF), and their horizontal position from the time diﬀerence between the left
and right PMTs of the rod. We report here the steps
that were followed to perform the calibration of thoseobservables. The procedures rely on the detection ofcosmic-ray muon events. To record these events, theneutron detector wall was in self-triggering mode withthe condition that at least 8 of the 116 scintillators
were ﬁred.
The wall was placed a few meters downstream of thetarget. It contained four layers of a plastic hodoscopearray consisting of 29 plastic scintillator rods (16 are
1 m long and 13 are 2 m long) with a section of 6×6 cm2and a PMT at each end. A thin (5 mm) layer of plastic
scintillators used as vetoes for charged particles wasplaced upstream of the wall.
Energy calibration of light output: To properly
set the detection threshold of deposited energy in theneutron scintillator rods, a calibration of light output
amplitude was required. Gamma-rays from 60 Co as

Fig. 1. Exploded view of neutron detector wall used in theexperiments detailed in Refs. 4 and 5. One can see
the cross-shaped layers of horizontal neutron scintillatorrods equipped with one photomultiplier tube (PMT) at
both ends. The thin vertical plastic scintillators on thefront face are used as vetoes.
∗1
∗2
∗3

148

Institut de Physique Nucléaire, France
Department of Physics, Rikkyo University
Department of Physics, Tokyo Institute of Technology

well as muon events were used for this purpose. To
eliminate the light attenuation eﬀect in plastic scintillators, the corresponding amplitude was the geometrical mean of the light output at√the right end (AR ) andat the left end (AL ): < A >= AL AR .
Muons reach the earth essentially vertically from thesky with a total energy of approximately 4 GeV6) anddeposit an energy of ≈ 12 MeV in one neutron plastic
scintillator. Due to straggling, the deposited energy
7)
see Fig. 2 (left), apfollows a Landau distribution,

8)proximated by Φ(λ) = e−(λ+e−λ ) /(2π), where λ is
proportional to the energy loss.
Time calibration: A calibration of the absolutetiming of each rod was made by a run utilizing a thickbrass target frame where a large amount of prompt
γ-rays were emitted. For TOF measurement, < T >=TR +TLdeﬁnes the arrival time in one neutron detector,2
where TR is the time measured for the right PMT and
TL the time measured for the left one.
Position calibration: Time diﬀerence ∆ T = TL −TR provides the longitudinal position along the rods,
namely the horizontal position. The maximum valueof ∆ T , ∆ Tmax , corresponds to photons that travel theentire scintillator length L. Then, L/∆ Tmax provides
the mm↔ns correspondence.
We corrected the remaining amplitude/position dependence eﬀect using arbitrary polynomial ﬁtting.
For the relative position alignment between the detectors within one layer, we selected the highest multiplicity from cosmic ray events. For one event, 29 pairsof hit coordinates (Xi , Yi )i=1,29 were ﬁtted to give anequation that describes the muon’s trajectory: X =αY + β. For one detector and all the events we calculated the distribution of diﬀerences between the ﬁtted
trajectory and real coordinates, ∆i X = Xi −(αYi +β),which gives the position measurement’s shift (for il-

Fig. 2. Left: Landau distribution of deposited energy ofmuons. Right: Example of muon track before position
correction (+) and after correction (◦), plotted with afitted track.

lustration see Fig. 2 (right)). The overall horizontal
position resolution for muons is 2 cm (FWHM).
Finally, the absolute position with consideration of
the entire setup is obtained by utilizing a proton beamrun. Protons stop in the ﬁrst layer at a well-known
position determined using vetoes.
Slew (walk) correction description: For timing
signals, leading edge (LE) discriminators were used,producing a strong time/amplitude dependence (seefor example Ref. 9) termed walk or slew. For an improved resolution of TOF or position measurement,
this eﬀect must be corrected.
We conﬁrmed that the “slew function”, which describes the time/amplitude dependence√ from the slew
0
eﬀect, has the form T√
R = TR − KR / AR for the rightside (TL = TL0 − KL / AL for the left), where AR or L
is the left or right light output, see Fig. 3 (left). In thefollowing, KR or L will be referred to as slew coeﬃcientor simply coeﬃcient. The rise time from the plastic
scintillator is ∼ 6 ns and therefore the time oﬀset fromthe slew eﬀect cannot be more than 6 ns.
The slew is corrected for each rod’s end according
to the above formulas. The amplitudes used for correction are strongly sensitive to the light attenuationof photons traveling through the plastic scintillator by
yet another time/amplitude dependence. We eliminated this eﬀect by selecting events from the center ofthe plastic rod, thus obtaining similar light attenuation
at both ends.
Finally, TOF for one neutron detector is deﬁned as:


KR
KL
1
+√
.
TR + TL + √< T >=
2
AR
AL
Slew correction procedure: We considered twoconsecutive detectors in one layer: one for correction(C) and one for reference (R). We deﬁne:δ TS (ACS ) = TSC (ACS ) − TSR (ACS ) ; S = Left, Rightδ T (< AC >) = δ TL (< AC >) + δ TR (< AC >) /2.

We ﬁtted the δTS vs. ACS distribution using the slewfunction and obtained the slew coeﬃcients.
We started from the top detector of a layer, called
1. By ﬁtting, we obtained slew coeﬃcients for bothsides of the next rod below, called 2. Since the reference detector was not corrected yet, these coeﬃcients
included the slew eﬀect from both the reference andcorrected detectors. In the case of an R detector witha high slew, coeﬃcients of the C detector can even be
negative and the time for low-energy events appears
less than that for high energy ones. We continued topropagate the correction, using 2 as a reference for 3,
then 3 for 4, up to 28 as a reference for 29.
We reiterated ﬁtting, keeping 1 untouched. The results from the ﬁt for a given detector were added toprevious values. Since previous studies showed that
all the coeﬃcient values were close to each other, weavoided possible divergences by smoothing the coeﬃcient value distribution at each iteration. When thelast detector had been ﬁtted, we restarted the same
propagation algorithm, from detector 2. This last detector is used as a reference for both 1 and 3, then 3
for 4 up to 28 as a reference for 29. We started again
from 3 as a reference for 4 and 2, then 4 for 5, 2 for 1,
and so on, see illustration in Fig. 3 (right).
The coeﬃcients obtained after using all the detectors
as starting points, i.e., after 29 resets, were averaged
to give the probable 29 (×2 sides) slew coeﬃcients.
We validated the correction by conﬁrming that neither δTS nor δT depends on ACS or < AC >, respectively, for all detectors. Coeﬃcients were of the order1of 4 ns.MeV 2
Conclusion and results: Calibration in time andposition of a large neutron detector array was performed using cosmic-ray muons. The position resolution for muons was 2 cm (FWHM) and the time resolution for γ was 850 ps.
The time resolution obtained by our method can becompared with that from “direct” correction using monoenergetic neutrons, emitted from the 7 Li(p,n)7 Be reaction, which provides after correction a resolution of
700 ps. We thus suggest that our present method canbe used for improving the time resolution of neutron
plastic detector walls without requiring beam time.
References

Fig. 3. Left: Experimental time shift (in ns) functionof signal amplitude (in MeV) for one PMT. Right:
Schematic explanation of propagation method throughplastic scintillators. In this case, we start from detector 3 and propagate to both up and down, while selecting the center of the scintillators to obtain a similar
light attenuation at both ends.

1) N. Fukuda et al.: Phys. Rev. C 70, 054606 (2004).
2) R. Palit et al.: Nucl. Phys. A 738, 45 (2004).
3) B. Luther et al.: Nucl. Instrum. Methods Phys. Res. A
505, 33 (2003).
4) J. Gibelin et al.: RIKEN Accel. Prog. Rep. 37, 63(2004).
5) Z. Elekes et al.: RIKEN Accel. Prog. Rep. 38, 50 (2005).
6) K. Hagiwara et al.: Phys. Rev. D 66, 010001 (2002).
7) L. D. Landau: J. Physics 8, (1944).
8) J. E. Moyal: Philos. Mag. 46, 263 (1955).
9) W. R. Leo: Techniques for Nuclear and Particle Physics
Experiments (Springer-Verlag, New York, 1994).

149

RIKEN Accel. Prog. Rep. 38 (2005)

Development of windowless solid hydrogen target
T. Ohnishi, H. Takeda, S. Ishimoto,∗1 S. Suzuki,∗1 T. Suda, I. Tanihata,∗2 and Y. Takahashi∗3
The requirement of a thin and ﬂat windowless solidhydrogen target becomes more important for experiments using an RI beam, particularly, proton elastic scattering and (p, 2p) reactions. For these experiments, the target thickness is limited to avoid energy
loss, multiple scattering, and energy straggling inside
the target in order to obtain high energy and angular resolutions. In addition, the number of hydrogenion is so small that the background from the window
becomes more serious. Furthermore, if the window iscurved and the target thickness becomes nonuniform,
the variation of the thickness has a signiﬁcant eﬀect on
the resolution. Therefore, to obtain a ﬂat target andreduce the background from the window, a windowlesssolid hydrogen target is needed.
The windowless solid hydrogen target has been developed recently.1,2) Although the researchers used liquid helium for the cooling system, it is better to use
a more compact cooling system so that it can be set
easily on the beam line and improve the ﬂexibility ofthe detector placement. Moreover, in the case of theself-supported target, the target was made only 10 mmthick.1) So, we have developed a thin self-supported
windowless solid hydrogen target using a small cryostat.
We have constructed a cooling system with a small
cryostat, SUMITOMO RDK-415D. The length anddiameter of the cooling system are approximately 40%
and 30% smaller than those of the previous system,1)
respectively. Concerning the detector placement, thesolid angle of the detector is about twice as large, because the detector can be located closer to the target. The measured cooling power of this cryostat was
1.35 W at 4.6 K.
Figure 1 shows the schematic view of the target cell.
This cell was made of pure copper, and consisted of adisk and a cell plate. The disk was connected to thecryostat by a copper block. The cell plate was 7 mm
thick and 50 mm wide. In its center, there was a holeof 30 mm diameter. A Pt-Co resistance thermometer
sensor was inserted into a thin hole drilled in the cell
plate beside the gas inlet.
The assembly for making a windowless target isshown in Fig. 2. During the solidiﬁcation process, bothsides of the hole were covered by Teﬂon-coated stainless steel plates. These plates were pressed tightly
on the cell plate with stainless steel bellows whichwere pressurized at approximately 5 atm with heliumgas. A 1-mm-thick indium gasket was used to obtain
∗1
∗2
∗3

150

High Energy Accelerator Research Organization
Argonne National Laboratory, USA
Research Center for Nuclear Physics, Osaka University

Fig. 1. Schematic view of target cell. The disk on the topof the cell was connected to the cryostat by a copper
block. The diameter of hole in the wall was 30 mm. The
inlet tube of hydrogen gas is also drawn.

Fig. 2. Assembly of Teflon-coated stainless steel plates andstainless steel bellows. Teflon-coated plates for fabrication of the 3-mm-thick target are shown. These were
pulled down lineally.

a vacuum-tight seal. Teﬂon-coated plates were separated from the crystal and the cell plate by evacuating helium gas inside the bellows. After separation,
the plates and the bellows were pulled down linearly.
The target thickness was determined by the shape ofTeﬂon-coated plates. In the present study, we usedthe designed plates to fabricate a 3-mm-thick target.
The eﬀective area of 3 mm thickness had a diameter of
20 mm.
An inlet tube for hydrogen gas was a thin stainlesssteel tube (3 mm OD and 2 mm ID). It was directly
introduced into the cell and connected only to the topof the hole to prevent the occurrence of solidiﬁcation
inside the tube.
The starting temperature of introducing hydrogengas was around 4 K. The pressure of the introducedhydrogen gas was controlled and maintained constantduring the solidiﬁcation; it was set to 60 Torr. The
cell temperature was increased to almost 6.5 K by theintroduction of the warm gas and then decreased gradually during the process of crystal growth. When thecell temperature returned to around 4 K, the solidiﬁcation was almost ﬁnished. Then, the teﬂon-coatedplates were separated. A photograph of the crystal isshown in Fig. 3. The crystal is very transparent withno voids and is self-supported.
The measurement of the crystal thickness was carried out using the laser iconometer, KEYENCE LK500. We measured the distance between the iconometer and the surfaces of the crystal and the cell, andscanned horizontally along the target at the verticalcenter. Figure 4 shows the result of the measurements.
The dashed line represents the shape of the Teﬂoncoated plate. Compared with the dashed line, theshape of the crystal was almost the same as that of theTeﬂon-coated plate. With the assumption of the same
shape on the back surface, the average thickness ofthe crystal was deduced as approximately 2.7±0.2 mm(r.m.s.).
After 10 days of operation, the thickness of thecrystal was the same within the error. However, acontamination was found on the surface of the crys-Fig. 4. Distance to surfaces of crystal and cell. The horizontal axis denotes the position along the target. The
vertical axis denotes the distance from the reference
point. The dashed line represents the shape of the
Teflon-coated plate.

tal. This was because the pressure at the start timeof the cooling, almost 10−5 Torr, was not suﬃciently
low. To avoid this problem, it is necessary to clean inside the chamber and start cooling at a pressure below
10−6 Torr.
Finally, we have developed a windowless solid hydrogen target with a small cooling system. A hydrogen crystal of 20 mm diameter and 3 mm thickness
was grown directory from normal hydrogen gas. The
crystal was self-supported and very transparent. From
the thickness measurement, the crystal had a uniform
thickness. Further developments to realize a thinnertarget is on going.
References

Fig. 3. Bare self-supported crystal inside the cell.

1) S. Ishimoto et al.: Nucl. Instrum. Methods Phys. Res.
A 480, 314 (2002).
2) P. E. Knowles et al.: Nucl. Instrum. Methods Phys. Res.
A 368, 604 (1996).

151

RIKEN Accel. Prog. Rep. 38 (2005)

Polarization calibration of spin-exchange-type polarized3
He target at RIKEN/CNS
K. Itoh,∗1 T. Uesaka,∗2 T. Wakui,∗2 T. Kawabata,∗2 Y. Shimizu,∗3 Y. Tameshige,∗3 K. Hatanaka,∗3
Y. Sakemi,∗3 A. Tamii,∗3 K. Fujita,∗3 T. Wakasa,∗4 H. Yoshida,∗4 T. Kudoh,∗4 H. Ohira,∗4 and H. Sakai∗5
A spin-exchange-type polarized 3 He target was developed at RIKEN/CNS. In 2002, this target was substantially modiﬁed to improve diagnostics capability
and performance.1) In the target system, the cell containing 3 He gas has the so-called “double-cell” structure. This structure consists of a target cell and an optically pumping cell, connected to each other througha pipe with an inner diameter of 10 mm. 3 He nuclei inthe pumping cell are polarized via spin exchange withpolarized Rb atoms. The polarized 3 He nuclei diﬀuses
into the target cell.
The polarization of 3 He nuclei in the target cell ismonitored by the adiabatic-fast-passage(AFP)-NMR
method, which provides a relative polarization value.
On the other hand, the polarization of 3 He nuclei in thepumping cell is obtained by measuring the frequency
shift of the Rb electron spin resonance (ESR). The
ESR method provides the absolute polarization value.
If the diﬀerence in 3 He polarization between the pumping cell and the target cell is suﬃciently small, the
AFP-NMR signal can be calibrated by measuring the
ESR frequency shift. To compare the polarization in
the target cell with that in the pumping cell, the absolute polarization of 3 He in the target cell is measured
 p, π + )4 He reaction, simultaneously with
via the 3 He(the ESR measurement.
The ESR frequency shift method has recently been
established as the accurate polarimetry method. The
ESR frequency of the Rb atoms is shifted by the presence of polarized 3 He gas. This is mainly due to thehyperﬁne interaction between a 3 He nucleus and a valence electron of a Rb atom. The frequency shift isgiven as2)
∆ν = Aκ0 [3 He]P3 He .

(1)

Coeﬃcient A weakly depends on the strength of thestatic magnetic ﬁeld applied to the target. P3 He is the3
He polarization and [3 He] is the 3 He density. κ0 is
the temperature-dependent coeﬃcient measured withan uncertainty of 1.5%2) . If the polarization of 3 He is
100%, the frequency shift is obtained to be 20.2 kHz
using Eq. (1) for [3 He] = 7.6 × 1019 atoms/cm3 , whichis the density in the calibration experiments describedin this report.
To observe ESR, Rb atoms are optically pumped
∗1
∗2
∗3
∗4
∗5

152

Department of Physics, Saitama University
Center for Nuclear Study, University of Tokyo
Research Center for Nuclear Physics, Osaka University
Department of Physics, Kyushu University
Department of Physics, University of Tokyo

Fig. 1. Configuration of the ESR frequency shift measurement.

into the F =3, m=−3 state, where F and m denote thetotal angular momentum and the magnetic quantum
number of a Rb atom, respectively. By applying an
RF ﬁeld that induces ESR between the m=−3 andm=−2 states, the population in the m=−2 state isincreased. Atoms in the m=−2 state absorb circularly
polarized laser light and succeedingly decay back to theground state by emitting ﬂuorescence photons. The
occurrence of ESR can thus be observed by detecting
the ﬂuorescence photons.
Figure 1 shows the experimental setup for the ESR
measurement. The cell is placed in a magnetic ﬁeld of∼20 G produced by main coils. The pumping cell isilluminated by circularly polarized laser light for optical pumping. The RF ﬁeld is produced using an ESR
coil. The RF frequency is modulated using a voltagecontrolled oscillator (VCO). The ﬂuorescence photons
are detected using a photodiode through a band-passﬁlter with a band width of 1.5 nm (FWHM). The detected ﬂuorescence signal is processed using a lockin ampliﬁer by considering the modulation frequency.
The processed signal is transmitted to a proportionalintegral feedback circuit, which is used to lock the RF
frequency to the ESR frequency. The locked frequency
is measured as an ESR frequency using a counter.
The ESR frequency strongly depends on thestrength of the magnetic ﬁeld. A ﬁeld ﬂuctuation of
10 mG corresponds to an ESR frequency ﬂuctuation of
4.5 kHz. In a previous measurement, the uncertaintyof the ESR frequency was mainly due to the magnetic
ﬁeld ﬂuctuation originating from the instability of apower supply.3) The stability of the power supply was
about 5×10−4 , leading to an ESR frequency ﬂuctuation of ∼2.5 kHz. To improve accuracy in the determination of the ESR frequency, a high-stability powersupply has recently been installed. Using the power
supply, the ESR frequency ﬂuctuation has been decreased to less than 1 kHz.
The calibrations of the polarization obtained fromthe ESR frequency shift have been performed before p, π + )4 He reaction. The result isand after the 3 He(shown in Fig. 2. The mean coeﬃcient of proportionality was deduced to be (4.85 ± 0.03)×10−4 mV−1 .
The error in the coeﬃcient was considerably decreased
from the previous measurement.3)
 p, π + )4 He reaction measurement has reThe 3 He(cently been performed to calibrate the AFP-NMR sig++
nal. For the case of 1 + 1 → 0− + 0+ , one can show
2

2

from the parity conservation that the polarization correlation coeﬃcient takes Cy,y =+1.4) In this case, thetarget polarization PyT is written asPyT =1 σ↑↑ + σ↓↓ − σ↑↓ − σ↓↑,
PyB σ↑↑ + σ↓↓ + σ↑↓ + σ↓↑(2)where PyB is the beam polarization and σ is the crosssection for respective combinations of the spin direction. The ﬁrst and second subscripts indicate the spin
directions of the beam and the target, respectively.
Thus, the absolute 3 He polarization in the target cell
can be directly deduced if the beam polarization is
known.
The experiment was performed at the Research Center for Nuclear Physics (RCNP), Osaka University, using a polarized proton beam. The beam energy was
392 MeV, the beam intensity was 20 nA, and the beampolarization was about (70±2)%. The beam polarization was monitored using beam-line polarimeters, on

the basis of the proton elastic and quasi-elastic scatterings from a polystyrene analyzer target. The pions
were momentum analyzed using the high-resolution
magnetic spectrometer Grand Raiden,5) and detectedusing two plastic scintillation counters and two verticaldrift chambers (VDCs).
The excitation energy spectrum is shown in Fig. 3.
 p, π + )4 He
The peak around Ex =0 was due to the 3 He(reaction. Small peaks at negative excitation energies
and continuum were background events mainly due
to the cell materials. Spin-dependent cross sections
were deduced after subtracting the background. The
absolute target polarization was obtained from thespin-dependent cross sections using Eq. (2). The direction of the beam polarization was reversed every
second, and the direction of the target polarization
was reversed every 2 hours. The polarization of the3
He target was measured by the AFP-NMR method
once per hour. The results of the calibration measurement are shown in Fig. 2 by closed triangles. The
mean coeﬃcient of proportionality was deduced to be(5.92±0.63)×10−4 mV−1 .
The results of the two diﬀerent calibration measurements do not agree within the error bar. The
re-examination of the systematic error in the ESR
frequency measurements and the analysis of the p, π + )4 He measurement are in progress.
3 He(

Fig. 3. Excitation energy spectrum at a beam energy of
392 MeV. The sharp peak around Ex = 0 is due to the
3 He(
 p, π + )4 He reaction.

References

Fig. 2. Correlation of the AFP-NMR amplitude andthe absolute value of 3 He polarization. Solid anddashed lines show the fitting results for the ESR and p, π + )4 He measurements, respectively.
3 He(

1) K. Itoh et al.: CNS Annu. Rep. 2002, 62.
2) M. V. Romalis et al.: Phys. Rev. A 58, 3004 (1998).
3) S. Yamamoto et al.: RIKEN Accel. Prog. Rep. 34, 198(2001).
4) G. G. Ohlsen: Rep. Prog. Phys. 35, 717 (1972).
5) M. Fujiwara et al.: Nucl. Instrum. Methods Phys. Res.
A 422, 484 (1999).

153

RIKEN Accel. Prog. Rep. 38 (2005)

Relaxation of proton polarization in polarized target
T. Wakui,∗1 M. Hatano,∗2 H. Sakai,∗1,∗2 T. Uesaka,∗1 and S. Sakaguchi∗1
A polarized solid proton target has been developed
using a crystal of naphthalene doped with 0.01 mol%pentacene.1) Among polarized solid proton targets,
this target is unique in that protons can be polarized ata low magnetic ﬁeld of 0.3 T and a higher temperatureof 100 K.2) This feature allows the target to be used
in a scattering experiment with an RI beam under the
inverse kinematic condition. The polarized proton target has been used for an experiment with a 6 He beamat the RIKEN projectile fragment separator (RIPS) in
July 20033,4) and also for a test experiment with a 4 He
beam at E3 in September 2004.5) The target system is
described in Ref. 3, and the polarization procedure is
described in Ref. 6.
The proton polarization, Pp , during polarizationbuildup can be written as7)
Pp =A
Pe {1 − exp[−(A + Γp )t]},A + Γp(1)

where Pe is the average population diﬀerence between
two sublevels in the triplet state, Γp the total relaxation rate of proton spins, and A the buildup rate
which is proportional to the laser power. The proton polarization is a result of the competition between
A and Γp . The relaxation rate is thus an importantfactor for the proton polarization.
During the buildup process, the relaxation of proton spins is caused by several sources, and Γp can be
written asΓp = ΓI + ΓL + ΓT ,(2)

where ΓI is the intrinsic relaxation rate, ΓL the relaxation rate caused by a cumulative eﬀect of laser irradiation, and ΓT the relaxation rate due to pentacenemolecules in the photoexcited triplet state. Since
pentacene molecules in the triplet state decay to theground state with a lifetime of 100 µs, ΓT disappears
after stopping laser irradiation.
The intrinsic relaxation of proton spins in a target
crystal below 250 K is mainly due to the ﬂuctuatingﬁeld produced by paramagnetic impurities.8) The relaxation rate ΓI measured at 100 K ranges from 0.044
to 0.060 h−1 , depending on the quality of the fabricatedcrystal.
The relaxation due to the cumulative eﬀect of laser
irradiation has been found recently. After laser irradiation, the relaxation rate measured without laser irradiation increased compared with ΓI . Figure 1 shows
the increase in relaxation rate, i.e., ΓL , as a functionof the product of laser power and time for laser irradiation. The relaxation rate ΓL was obtained from the
∗1
∗2

154

Center for Nuclear Study, University of Tokyo
Department of Physics, University of Tokyo

Fig. 1. Relaxation rate ΓL due to cumulative eﬀect of laser
irradiation.

relaxation rate measured without laser irradiation by
subtracting ΓI . The solid line shows the least-squares
ﬁt of a linear function. The proportionality constantwas (1.1 ± 0.5) × 10−3 W−1 h−2 .
The relaxation due to pentacene molecules in thephotoexcited triplet state is caused by the interaction
between triplet and proton spins. Figure 2 shows ΓT as
a function of laser power. The relaxation rate ΓT was
obtained from the relaxation rate measured with laser
irradiation by subtracting ΓI and ΓL . The relaxation
rate ΓT increased almost linearly with the laser power.
The linear increase would be attributed to the fact thatthe number of pentacene molecules in the triplet stateis proportional to the laser power unless an opticaltransition is saturated.9) The solid line shows the leastsquares ﬁt of a linear function. The proportionality
constant was 0.26 ± 0.06 W−1 h−1 .
In addition to the relaxation process due to thesesources, we found the relaxation process caused by ionbeam irradiation. After the experiment with the 6 He
beam, the relaxation rate measured without laser irradiation increased from 0.06 to 0.13 h−1 . From the measured relaxation rate, the relaxation rate due to ion-Fig. 2. Relaxation rate ΓT caused by interaction between
triplet and proton spins.

beam irradiation, ΓB , was obtained as 0.065 ± 0.11 h−1
by subtracting ΓL . In this experiment, the target crystal was irradiated by a 6 He beam of 71 MeV/u with a
total dose of 1.5 × 108 mm−2 . For the experiment withthe 4 He beam, the relaxation rate ΓB was obtained as
0.284 ± 0.015 h−1 in the same manner. In this experiment, the target crystal was irradiated by a 4 He beamof 80 MeV/u with a total dose of 7 × 108 mm−2 . Although the experimental conditions such as the beamenergy and the beam-spot size on the target are different in each experiment, we attempted to plot ΓBagainst the total dose in a ﬁgure. Figure 3 shows ΓB
as a function of total dose. The relaxation rate ΓBseemed to increase almost linearly with the total dosein the range of the experiments. The proportionality
constant was (4.07 ± 0.04) × 10−2 h−1 /108 mm−2 .
To compare the contribution of each source to therelaxation rate during a scattering experiment, we calculated the dependence of the relaxation rate on timeusing each proportionality constant. Figure 4 shows
the result of the calculation. In this calculation, we assumed that ΓI is 0.05 h−1 , the laser power is 200 mW,
the beam intensity is 2 × 105 , and the beam-spot sizeon the target is 10 mm φ. From this ﬁgure, we can seethat ΓB increases rapidly with time and becomes aslarge as the sum of the relaxation rates due to othersources at the irradiation time of 5 days.
For a higher beam intensity, ΓB will increase more
rapidly. Since the proton polarization decreases withincreasing relaxation rate, ΓB should be reduced periodically by changing the target crystal or by annealing.
We then investigated the eﬀect of annealing after thetest experiment with the 4 He beam. The investigation
was carried out by measuring the relaxation rate without laser irradiation after annealing at diﬀerent temperatures. Figure 5 shows ΓB plotted against time.
The relaxation rate ΓB was obtained from the measured relaxation rate by subtracting ΓI . The relaxation
rate ΓL was smaller than the error bars. For the ﬁrst
63 hours, the temperature of the target crystal irradiated by the 4 He beam was maintained at 100 K. During the ﬁrst period, the relaxation rate ΓB remained
constant at around 0.3 h−1 . The temperature of thecrystal was then increased and maintained at 150 K
for the next 6 hours. At 150 K, the relaxation rate ΓB
decreased, but the eﬀect of annealing was small. For
the last 16 hours, the temperature of the crystal wasmaintained at 200 K. The relaxation rate ΓB clearlydecreased at 200 K. From these results, the temperature of the target crystal should be increased to higher
than 200 K for annealing.

Fig. 5. History of relaxation rate ΓB during annealing.
Fig. 3. Relaxation rate ΓB caused by ion-beam irradiation.

References

Fig. 4. Time dependence of the relaxation rate due to eachsource.

1) T. Wakui et al.: RIKEN Accel. Prog. Rep. 34, 194(2001).
2) A. Henstra et al.: Chem. Phys. Lett. 165, 6 (1990).
3) T. Uesaka et al.: Nucl. Instrum. Methods Phys. Res. A
526, 186 (2004).
4) M. Hatano et al.: RIKEN Accel. Prog. Rep. 37, 44(2004).
5) S. Sakaguchi et al.: RIKEN Accel. Prog. Rep. 38, 36(2005).
6) M. Hatano et al.: RIKEN Accel. Prog. Rep. 33, 182(2000).
7) M. Iinuma et al.: Phys. Lett. A 208, 251 (1995).
8) J. U. von Schuetz et al.: Z. Naturforsch. 27, 42 (1972).
9) T. Wakui et al.: Nucl. Instrum. Methods Phys. Res. A
526, 182 (2004).

155

RIKEN Accel. Prog. Rep. 38 (2005)

Development of neutron polarimeter
K. Yako,∗1 H. Sakai,∗1 H. Saenma,∗1 M. Oizumi,∗1 Y. Takahashi,∗1
M. Sasano,∗1 T. Kawabata,∗2 and H. Kuboki∗1
To test Bell’s inequality1) in a proton-neutron system, a beam time is scheduled for the measurementof the spin correlation between the proton and neutron in 1 S0 produced by the 6 Li(d, pn)6 Li[0+ , T =1; 3.56 MeV] reaction at E = 135A MeV. In this measurement, the polarization of the proton is analyzed
using a focal plane polarimeter2) at SMART in theE4 experimental area, while that of the neutron isanalyzed using a neutron polarimeter (NPOL), which
is currently under development. The requirement of
NPOL is an energy resolution of < 1 MeV and a ﬁg2−5, where n andure of merit (FOM) of n (Aeﬀy ) > 10eﬀ
Ay are the double scattering eﬃciency and the eﬀective analyzing power of NPOL, respectively. In thisyear, a prototype NPOL was fabricated and tested.
Figure 1 shows a schematic view of NPOL. It
consists of three planes, each of which consists ofsix plastic scintillators (Bicron BC408) with a size of
10 × 60 × 3 cm3 . Each scintillator is viewed from bothsides by photomultiplier tubes (PMTs) such that thepositions are obtained from the timing information derived from the PMTs. The typical position resolution
is ±4 cm in the longitudinal direction of the scintillator. The ﬁrst neutron plane serves as a neutron polarization analyzer (NA), while the two planes placeddownstream of 60 cm serve as neutron catchers (NC1and NC2). The polar angle θ and azimuthal angle φ of
the neutron scattering in NA are determined from theposition information in NA and NC. The most useful
event is the elastic scattering of a neutron by a proton
in NA and its detection in either NC1 or NC2.3) To
eliminate the signals due to the charged particles in
the counter planes, three sets of thin plastic scintillators with a size of 20 × 60 × 0.5 cm3 are placed in frontof the analyzer plane and the catcher planes.
The measurements of n and Aeﬀ
y were performed
using the polarized neutron beams produced by the n)X reaction at 0◦ at Ed = 180 MeV. The energyC(d,of the neutron beams was En ∼ 90 MeV and the ﬂux

was ∼ 1 × 109 /s in NPOL located 21 m away from thetarget. The typical polarization of the deuteron beam
was pd = 0.53 ± 0.02.4) Using the polarization transfer
coeﬃcient of Kyy (0◦ ) = 2/3,5) the polarization of theneutron beam was estimated to be pn = − 32 Kyy pd ≈=−0.53.
The energy of the neutron was obtained by the timeof-light (TOF) technique. A kinematical discrimination of the n + p events from the n + C events was
performed by considering the time, position, and pulseheight information. For example, the neutron velocity
between NA and NC vexp obtained from the TOF andthe ﬂight path length determined by θ was comparedwith the velocity calculated from the incoming neutron energy and the scattering angle θ, assuming then + p kinematics (vNN ). The sector method was applied to obtain the left/right asymmetry,3) where theneutrons with the scattering angles within the regionsof θmin < θ < θmax and |φ| < Φ (|φ − π| < Φ) areconsidered to be scattered in the right (left) direction(see Fig. 2).
The software cuts were optimized, as shown in Table 1, to obtain the maximum FOM. The results are−5, Aeﬀ= 0.25 ± 0.01, and FOM =n = 2.3 × 10
y−6
1.7 × 10 , where the statistical error is denoted for
Aeﬀ
y . The systematic uncertainty due to the uncertainty in pn was estimated to be ±0.01. We are preparing a new NPOL with 12 planes to achieve an FOM
value of 2 × 10−5 .

Fig. 2. Sector deﬁnition for the left/right asymmetries.
Table 1. Optimized cuts used in the neutron polarimeter.
QuantityCutφΦ = 66.8◦
θ(θmin , θmax ) = (16.0◦ , 36.5◦ )Pulse height in analyzer> 5.5 MeVee
Pulse height in catcher> 4.0 MeVee
Velocity ratio vNN /vexp
0.88–1.10

References

Fig. 1. Schematic view of the neutron polarimeter. The
polar angle θ and the azimuthal angle φ are indicated.
∗1
∗2

156

Department of Physics, University of Tokyo
Center for Nuclear Study, University of Tokyo

1) J. S. Bell: Physics 1, 195 (1964).
2) T. Saito et al.: CNS Annu. Rep. 2003, 19.
3) M. Palarczyk et al.: Nucl. Instrum. Methods Phys. Res.
A 457, 309 (2001).
4) H. Mardanpour et al.: RIKEN Accel. Prog. Rep. 38,
157 (2005).
5) H. Sakamoto et al.: Phys. Lett. B 155, 227 (1985).

RIKEN Accel. Prog. Rep. 38 (2005)

Determination of vector- and tensor-analysing powers in elastic
 α)10 B∗ (2+ ) reaction
deuteron-proton scattering via 12 C(d,H. Mardanpour,∗1 H. R. Amir Ahmadi,∗1 N. Kalantar-Nayestanaki,∗1 T. Kawabata,∗2 H. Kuboki,∗3
Y. Maeda,∗2 J. G. Messchendorp,∗1 S. Sakaguchi,∗2 H. Sakai∗2 ,∗3 N. Sakamoto, Y. Sasamoto,∗2 K. Sekiguchi,
K. Suda,∗2 Y. Takahashi,∗3 T. Uesaka,∗2 and K. Yako∗3
The measurement of the analysing powers of
deuteron-proton elastic scattering at Ed = 180 and
130 MeV was carried out at RARF in May 2004. The
experiment was composed of two parts. In order tomeasure the asymmetries of deuteron-proton elastic
scattering, the ﬁrst part is performed with the Droom in-beam polarimeter.1) Simultaneously using thesame beam, the beam polarization was measured via
12 α)10 B∗ (2+ ) reaction using the SMART spectroC(d,graph. The analysing powers in deuteron-proton elastic scattering were measured for beam energies of 180
and 130 MeV for 6 diﬀerent angles in the center-ofmass reference frame.
In a coordinate with z-axis parallel to the beam direction, the cross section of a reaction with polarized
deuteron beam of the quantization axis (Z) perpendicular to the reaction plane is expressed as:2,3)√σ= 1 + 3pZ iT11 (θ) cos φ
σ0 (θ)√
3
1
pZZ T22 (θ) cos (2φ) ,− √ pZZ T20 (θ) −2
8(1)
where θ and φ are the polar and azimuthal scattering
angles, respectively. Plastic scintillator detectors on
the right, left, upper and lower (φ = 0◦ , 180◦ , 90◦ ,270◦ ) sides of the target measure the asymmetries in
the reaction of a polarized beam with a CH2 target.
The polarization state of deuteron beam switches between oﬀ-mode (pZ = 0, pZZ = 0), mode-1 (pZ = 13 ,pZZ = −1), and mode-3 (pZ = 13 , pZZ = +1). The
quoted values for pZ and pZZ are the theoretical maximum values.
For θ = 0◦ , the cross section relation is simpliﬁed to1σ = σ0 (θ) 1 − √ pZZ T20 (θ) .
(2)8 α)10 B∗ reaction with
A measurement of the 12 C(d,the SMART spectrograph enables the unambiguous
extraction of the beam polarization. The identiﬁcation of the 2+ excited state, which has a clear andbackground-free peak, makes it possible to determine
the number of α particles (Fig. 1) corresponding tothis excited state. The beam polarization can subsequently be extracted since the analysing power of
∗1
∗2
∗3

Kernfysisch Versneller Instituute (KVI), Netherlands
Center for Nuclear Study, University of Tokyo
Department of Physics, University of Tokyo

Fig. 1. Excitation energy spectrum of 10 B.

the 2+ state is known exactly at zero degrees to be
T20 (θ = 0) = √12 . Therefore, by measuring the asymmetry at θ = 0◦ , it is possible to obtain the beampolarization. The exact measurement of beam asymmetry at θ = 0◦ is not possible. The asymmetryat θ = 0◦ is, therefore, obtained from an extrapolation of an asymmetry measurement at ﬁnite angles between θ = 1◦ − 4◦ and using a second-order polynomial ﬁt. The asymmetries of mode-1 and mode-3 arefound to be −0.200 ± 0.009 and +0.205 ± 0.003, respectively. The extrapolation at θ = 0◦ is demonstrated inFig. 2. These yields pZZ values of mode-1 and mode3 of −0.801 ± 0.036 and 0.821 ± 0.012, respectively,
for a polarized deuteron beam at 180 MeV, and pZ isdetermined by assuming that pZ = 13 | pZZ |.4)
The D-room polarimeter is composed of 6 diﬀerent
proton counters placed at angles listed in Table 1.
For each proton detector, the corresponding
deuteron counter is located on the other side of thebeam. Thus the setup makes it possible to measure
the asymmetries at 6 diﬀerent angles. The deuteronbeam interacts with the CH2 target placed at the center of the polarimeter.
By measuring asymmetries in the horizontal andvertical planes in the D-room polarimeter and using
the obtained polarization values from SMART, theanalysing powers of the d − p reaction can be calculated using the asymmetries

157

Some preliminary analysing powers of the elastic
deuteron-proton reaction at 180 MeV are shown in
Fig. 3. The open squares and open triangles correspond to T20 , the ﬁlled squares and ﬁlled up triangles correspond to T22 , the open circles and upside
down ﬁlled triangles correspond to iT11 for mode-3 andmode-1 polarization states, respectively.

 α)Fig. 2. Asymmetry versus the scattering angle of 12 C(d,10 ∗ +B (2 ) reaction. The open circles correspond to thedata fitted for mode-1 and the filled triangles correspond to data fitted for mode-3.

Table 1. Positions of deuteron and proton detectors.
Label
P120
P5
P4
P3
P2
P1

P-lab (deg)
29.7
33.3
38.3
41.3
44.3
47.3

d-lab (deg)
30.0
29.6
28.4
27.4
26.2
24.9

θCM
118.7
111.2
101.2
95.2
89.1
83.2

Fig. 3. Preliminary analysing powers. The open squares
and open triangles correspond to T20 , the filled squares
and filled up triangles correspond to T22 , the open circles and upside down filled triangles correspond to iT11
for mode-3 and mode-1 polarization states, respectively.

References√
L − R = 2 3iT11 pZ ,√R + L − U − D = −2 3T22 pZZ ,1
R + L + U + D = 4 1 − √ T20 pZZ .
8

158

(3)
(4)
(5)

1) K. Sekiguchi et al.: Phys. Rev. C 65, 034003 (2002).
2) G. G. Ohlsen: Rep. Prog. Phys. 35, 717 (1972).
3) R. Bieber et al.: Nucl. Instrum. Methods Phys. Res. A
457, 12 (2001).
4) K. Suda et al.: RIKEN Accel. Prog. Rep. 35, 174(2002).

RIKEN Accel. Prog. Rep. 38 (2005)

Development of extraction and neutralization system
for atomic beam resonance method
D. Nagae,∗1 K. Asahi,∗1 H. Miyoshi,∗1 K. Shimada,∗1 A. Yoshimi, M. Uchida,∗1 H. Ueno,
J. Murata,∗2 Y. Kobayashi, T. Haseyama, D. Kameda,∗1 S. Emori,∗1 G. Kato,∗1 S. Oshima,∗1
G. Kijima,∗1 M. Tsukui,∗1 T. Arai,∗1 and M. Takemura∗1
The prime tasks for realizing the RI atomic beam
resonance (RIABR) method are (1) stopping the RI
beam produced by an intermediate nuclear fragmentation reaction in a gas volume, (2) extraction of the
stopped RIs using ions drifting in a static electric ﬁeld,(3) neutralization of the RI ions, (4) transportation of
the RI atoms into the spin selection system.
On-line measurements of stopped and drifting ionswere performed at RIKEN using an RI beam delivered by the fragment separator RIPS. The details aredescribed elsewhere.1,2) In addition, we have been performing an oﬀ-line experiment in order to study the extraction and neutralization eﬃciencies of the developed
device. A schematic view of the oﬀ-line setup is shownin Fig. 1. A new ion source was designed and installed
for this experiment. A static electric ﬁeld formed using
many ring electrodes2) is applied in the drift chamberin order to guide the ions towards a Laval-type glass
nozzle; the ions are extracted into an active neutralization system through the nozzle.
Ions are produced by arc discharge in the nitrogengas ﬂow and the nitrogen ions are extracted into the ion
drift chamber with an electric ﬁeld together with gas
ﬂow. In the ion drift chamber, the ions are guided using an electric DC ﬁeld and the gas ﬂow toward to thenozzle. The total voltage applied to the ring electrodes
is 400 V. The pressure of nitrogen gas in the ion drift
chamber was maintained at approximately 150 Torr.
The transported ions are detected using a Faraday cup
which is located downstream of the ion source at the
ground potential. The distance from the ion source
was changed from 10 mm to 320 mm. The measurement result is shown in Fig. 2. The current of ionswhich was measured just downstream of the ion source
using the Faraday cup was approximately 62.5 nA corresponding to 1012 particles/sec, assuming that all ofFig. 1. Schematic view of experimental setup.
∗1∗2Department of Physics, Tokyo Institute of Technology
Department of Physics, Rikkyo University

Fig. 2. The ion counts measured by replacing Faraday cups
in the drift chamber (0–320 mm) and in the downstream
chamber (360 mm). A 1-mm-diameter nozzle was usedin this measurement. The position of the ion source
exit is deﬁned as 0 mm and that of the nozzle exit is
350 mm.

the ions that were measured using the Faraday cup are
single charged ions. At the end of drift chamber, theion current was 10.2 nA (1.63×1011 particles/sec). The
low transmission eﬃciency in this oﬀ-line measurementcompared with the previously reported on-line result1)
is considered to be due to the large diﬀerence in neutralization cross section between the nitrogen atoms
and the Al ions and Ne atoms.1) We have not yet investigated other mechanisms for this low transmission,
such as the space charge eﬀect. In order to measure
the extraction eﬃciency from the drift chamber, theions extracted through the nozzle are detected using
another Faraday cup located at the distance of 10 mmfrom the nozzle exit. We used two types of nozzle,
whose diameters were 0.5 mm and 1 mm, in order toinvestigate the dependence of the extraction eﬃciency
on the nozzle diameter. The current of the extracted
ions that pass through the 1-mm-diameter nozzle is
4 times larger than that passes through the 0.5-mmdiameter nozzle. This value is consistent with the ratioof the cross section of the nozzle apertures, suggesting that the converging spot size of the ions at thenozzle is larger than φ1 mm due to incomplete focusing by the static electric ﬁeld. The current of the extracted ions with the 1-mm-diameter nozzle was 0.3 nA(5.36 × 109 particles/sec). From this result, the extraction eﬃciency of the nozzle was found to be 4.1×10−2 .
The neutralization system consists of a yttrium
tube, a SUS tube and a wire, as shown in Fig. 3.
A DC bias of −200 V is applied to the yttrium and159

RY = 1 − AY BY ,RSUS = 1 − ASUS BSUS .

(5)
(6)

From Eqs. (5), (6) and (3), the neutralization eﬃciencyof the yttrium tube γY is described as
1 − RYASUS
γY = 1 −(1 − γSUS )1 − RSUS
AY



ASUS
1 − RY.
(7)≥ 1−
1 − RSUS
AY
Fig. 3. The neutralization system. The length of the yttrium tube is 110 mm and the inner diameter is 8 mm.

SUS tubes, so that ions are drifted to the yttrium
tube by the electric ﬁeld and converted into neutral
atoms by neutralization in charge-transfer collisions
with the yttrium tube. After passing through the yttrium tube, the neutral atoms were detected with thequadrupole mass spectrometer (QMS422) placed in thedownstream chamber.
In order to experimentally estimate the neutralization eﬃciency of this system, we measured the neutral
atoms on the QMS under four kinds of situation, where
the ion source was switched on or oﬀ, and the yttrium
tube was installed or removed (SUS tube only). The
procedure for determining the neutralization eﬃciency
is as follows. The ratio (R) of the detected numberof atoms with ion source on (Non ) and oﬀ (Noﬀ ) is
described as
NonNoﬀ[1 − α(1 − β)(1 − γ)(1 − ε)]N0=,
N0In this experiment, nitrogen gas was used as the ion
source. Argon gas was employed as a carrier gas andthe gas pressure in the chamber was approximately
75 Torr. The neutral N2 was measured with the ion
source oﬀ for 120 seconds, and just after switching on
the ion source the same measurement was performedfor 120 seconds. The set of these two measurements
was repeated and the averaged counting rates with theion source on/oﬀ were compared in order to reduce theinﬂuence of the instability of the system parameters,such as α and gas-ﬂow rate. The above procedure was
employed for the yttrium tube and for only the SUS
tube. The presently obtained data is summarized inFig. 4. This ﬁgure shows the relative diﬀerence R between Noﬀ and Non normalized using Noﬀ . A notablediﬀerence between RY and RSUS was observed. We arenow evaluating the ionizing eﬃciency α and the stability of α, β, ε, in order to understand this diﬀerence
and to estimate γY .

R =

(1)

where N0 is the number of atoms introduced into theion source, α is the ionization eﬃciency of the ion
source, β is the neutralization probability in the drift
chamber, γ is the active neutralization eﬃciency inthe neutralization system and ε is the neutralization
probability of downstream of the neutralization system. Here, we deﬁne A and B for simplicity as
A = α(1 − β)(1 − ε)B = (1 − γ).

(2)
(3)

Equation (1) is redeﬁned with Eqs. (2) and (3) as
R = 1 − AB.

References(4)

The ratio R with the yttrium tube and with only the
SUS tube can be deﬁned as

160

Fig. 4. The counting ratio with the ion source on/oﬀ withand without Yttrium.

1) H. Miyoshi et al.: RIKEN Accel. Prog. Rep. 38, 166(2005).
2) K. Shimada et al.: RIKEN Accel. Prog. Rep. 38, 163(2005).

RIKEN Accel. Prog. Rep. 38 (2005)

Space-charge eﬀects in a catcher gas cell of an rf ion guide
A. Takamine,∗1 M. Wada, Y. Ishida, T. Nakamura,∗2 T. Kambara, H. Ohyama, Y. Kanai, T. M. Kojima,
Y. Nakai, N. Oshima, A. Yoshida, T. Kubo, K. Okada,∗3 T. Sonoda,∗4 K. Noda,∗5 S. Ohtani,∗6 I. Katayama,∗2
Y. Yamazaki, H. Wollnik, and V. Varentsov
A universal facility for slow radioactive ion beams(SLOWRI) is being developed1) as part of the RIKEN
radioactive ion beam factory (RIBF).2) SLOWRI aims
to provide universal slow RI-beams of high purity andsmall emittance by slowing down and cooling energetic
RI ions using an rf ion guide.
We have tested the rf ion guide with 100 MeV/
nucleon 8 Li beams provided by the RIKEN projectile
fragment separator RIPS. A schematic of our experimental setup is shown in Fig. 1. Figure 2 shows theion guide eﬃciencies η deﬁned as the ratio between thenumber of extracted slow 8 Li+ ions to the number ofthermalized 8 Li in the gas cell as determined from theenergy distribution of 8 Li behind the degrader and thestopping power of the He gas. We ﬁnd that, for large
values of N0 , eﬃciency decrease as η ∝ N0−0.53 .
We consider that the reduction of eﬃciency η withthe above-described dependence on the incoming beam
intensity N0 results predominantly from the spacecharge eﬀects. When the incoming 8 Li ions are slowed
down by collisions with He atoms, they form one
electron-He+ pair for every 41 eV deposited. Since theelectrons have a very high mobility even a small electricﬁeld drives the electrons away to the wall of the gas cellso that ions, a signiﬁcant fraction of which He+ ionsaccount for, are left as space charge along the track

Fig. 1. Schematic of our experimental setup. Refer toRefs. 1 and 3 for details. Ions thermalized in the gas cell
are tranported by linear dc ﬁeld Ez toward the “rf carpet.” 1) A detector of alpha-rays or of charged particles
is located behind an rf six-pole beam guide (SPIG).4)
In our experiments, the gas cell was inclined by several degrees relative to the beam axis in order to hide
the detector form the light high-energy ions provided
by RIPS.
∗1
∗2
∗3
∗4
∗5
∗6

Graduate School of Arts and Sciences, University of Tokyo
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Department of Physics, Sophia University
Cyclotron and Radioisotope Center, Tohoku University
National Institute for Radiological Science
Institute for Laser Science, University of ElectroCommunications

Fig. 2. Ion guide eﬃciency η deﬁned as the ratio of thenumber of ions collected per second downstream of the
SPIG and the number of thermalized 8 Li ions in thegas cell. Comparison of the experimental eﬃciencies
ηexp and the eﬃciencies ηsim derived numerically fromthe trajectories shown in Fig. 3. Here, two cases of thelinear dc ﬁeld are shown. The dependences of ηexp andηsim on the beam intensity were ηexp = 1.0 × 103 ×
N0−0.40 and ηsim = 2.6 × 103 × N0−0.25 when the dc
ﬁeld along the gas cell axis was Ez ≈ 0.2 V/mm, forEz ≈ 0.1 V/mm, they were ηexp = 2.1 × 102 × N0−0.29
and ηsim = 7.1 × 102 × N0−0.27 .

of beams in a 2000-mm-long cylinder of ≈ 80 mm diameter. On account of the contribution of 8 Li ions to
the production of He+ ions and an additional ≈ 50%
contribution from impurity ions in the incoming beam,such as 7 Li and 10 Be, an incoming beam of 103 to 107
8
Li ions produces 109 to 1013 He+ ions, namely, 102 to
106 ions per mm3 . The space charge generates a ﬁeld
which drives a large portion of ions, including He+ ,towards the wall of the cell.
The distribution of the space-charge density ρ(t, r, z)
at time t and position r, z can be calculated using
the continuity equations and Maxwell’s equations.5) A
solution to these equations for cylindrical coordinates,
neglecting the z-dependence of ρ, is(1)
ρ0 = 0 Qi /µ ∝ N0ρ0r ≤ r0
ρ(r) =(2)
ρ0 / 2r 2 /r02 − 1 r ≥ r0
ρ0 rµ/20r ≤ r0v(r) =(3)2
2
2
ρ0 2r /r0 − 1(µr0 /2r0 ) r ≥ r0
where 0 is the dielectric constant, Qi is the newly

161

Fig. 3. The dc potential distributions (thin lines) and the ion trajectories (thick lines) in the catcher gas
cell for N0 = 104 , 106 and 108 incoming energetic 8 Li ions. All distributions are shown as functionsof the radial coordinate r and of the axial coordinate z in a cylindrical tube of 300 nm diameter and2000 mm length.

formed charge per unit volume and unit time, and v =µE is the velocity of He+ in a ﬁeld E, and µ being themobility of He+ ions in a He gas.
Knowing ρ(r) for N0 = 104 , 105 , 106 from Eq. (2),one can calculate the dc electric potential distributions.
These are plotted in Fig. 3 together with the trajectories of the thermalized ions derived numerically fromMonte Carlo simulations. The potential slopes produced by the cylindrical electrodes and the “rf carpet”
electrodes are distorted by the space charge that upheaves the potential slope to a “ridge.” With a higher
intensity of incoming 8 Li ions, only ions very close to
the “rf carpet” can be extracted.
One way to conﬁrm the present space-charge modeland the simple simulation is to record the He+ -current
that reaches the “rf carpet” when the rf-voltage isswitched oﬀ. The results of such measurements areshown in Fig. 4, together with the results of our simulations. The dependences of the He+ -ion currents arein good agreement between the results of experiments
and those of simulations. The small diﬀerences thatthe absolute numbers of He+ ions are ≈ 30% higher
in the simulations than in the experiments may be a
result of the cell axis being inclined by 3◦ relative tothe incoming beam axis in these experiments.
We also compared the simulation results with theexperimentally obtained ion guide eﬃciency ηexp for
8 +Li ions (Fig. 2). Reasonably good agreements arefound between the dependences of the eﬃciencies in theexperiment and in the simulation, while their absolutevalues diﬀer by a factor of ≈ 4. This results mainly
from the inclination of ≈ 5◦ of the gas cell relative tothe beam, since in the He+ -ion current measurements,
the 5◦ inclination reduced the He+ -ion current to ≈50% of that with 3◦ inclination. The slightly faster
fall oﬀ in the experiment might be explained by thefact that the transport eﬃciency at the “rf carpet” isreduced for higher beam intensities because a larger dc
ﬁeld that is caused by the increased space charge faces
the “rf carpet.” The most important observation isthat decreases of the ion guide eﬃciencies are observed

162

He
Fig. 4. The He+ currents Iexp
collected experimentally inthe “rf carpet” and the calculated intensities of He+
He
ions Isimare shown as a function of N0 , the number ofincoming 8 Li ions. A solid line indicates the case where
the eﬃciency is unity. The dependence of the He+ -ionHecurrent I(N0 ) [pA] are ﬁtted to be Iexp
= 34 × N00.65
He
0.64
He
and Isim = 47 × N0
for Ez = 0.25 V/mm and Iexp
=
0.63
He
0.64
43 × N0and Isim = 52 × N0
for Ez = 0.5 V/mm.

at almost the same magnitude of intensity of incoming
8
Li ions. This supports our assumption that the spacecharge region created by He+ ions has a profound eﬀect
on the ion guide eﬃciencies in a catcher gas cell.
References
1) M. Wada et al.: Nucl. Instrum. Methods Phys. Res. B
204, 570 (2003).
2) M. Motobayashi: Nucl. Instrum. Methods Phys. Res. B
204, 737 (2003).
3) A. Takamine et al.: RIKEN Accel. Prog. Rep. 37, 173(2004).
4) H. Xu et al.: Nucl. Instrum. Methods Phys. Res. A 333,
274 (1993).
5) A. Takamine: Master’s Thesis, University of Tokyo(2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Development of RI Extraction System with Static Electric Field
K. Shimada,∗1 K. Asahi, H. Miyoshi,∗1 D. Nagae,∗1 A. Yoshimi, H. Ueno, Y. Kobayashi, T. Haseyama,J. Murata,∗2 M. Uchida,∗1 D. Kameda,∗1 S. Emori,∗1 G. Kato,∗1 S. Oshima,∗1 G. Kijima,∗1
M. Tsukui,∗1 T. Arai,∗1 and M. Takemura∗1
The Radioactive Isotope (RI) extraction system witha static electric ﬁeld has been developed to produce
a slow RI beam for the RI Atomic Beam Resonancemethod (RIABR). A key issue for realizing the RIABR
method is the formation of a slow neutral RI beam.1)
At ﬁrst, we measured a drift eﬃciency of 30 Al stopping in Ne at 600 Torr.2) A setup of the experiment isshown in Fig. 1 of Ref. 2. The twenty electrodes installed outside of the glass chamber were 200-µm-thickdiscs of 8.0 cm o.d. and 5.0 cm i.d. They were connected using 300 kΩ resistors at 18 mm intervals to create a uniform electric ﬁeld. The high voltage applied
between the ﬁrst electrode and the 19th one was 3 kV.
The high voltage of the last electrode was the same as
the 18th one due to trapping of the extracted 30 Al. We
calculated the electric ﬁeld using POISSON as shownin Fig. 1, and obtained a uniform axial electric ﬁeld of
87 V/cm. In this calculation, the space charge createdby the incident beam was not taken into account. From
analyzing the experimental result,2) we conﬁrmed thatthe electric ﬁeld could drift the RI stopped in Ne gas,and obtained a drift eﬃciency of 0.72 (4).
We have also performed an extraction eﬃciency
measurement. The experimental setup is shown in
Fig. 2. The intensity of the collimated 30 Al beam was
3.7 × 104 particles/s. The upstream RI stopping chamber was the same as that described in Ref. 1 except for
the applied high voltages and the size of the oriﬁce. In
this experiment, the applied high voltage was +816 V
and the oriﬁce was 0.5 mm i.d. Therefore, the electricﬁeld of the drift volume was 3.1 V/cm. Upstream, theRI-stopping chamber was ﬁll with 600-Torr Ne. Downstream, the jet-separator (JS) chamber was evacuated
to 0.12 Torr. After passing through the oriﬁce between

these two chambers, the RI and the carrier gas formed
jet and diﬀused into volume. Nine electrodes were installed to guide ions using parallel electric ﬁeld fromthe oriﬁce to further downstream. We installed two
scintillators. One was placed at the entrance of the
stopping chamber to monitor the number of incident
30
Al beams. The other was a 100 mm × 100 mm ×
110 mm cube with a hole of 70 mm i.d. and 80-mmlong cylinder. It was placed in the JS chamber, whilea photomultiplier tube was placed outside the chamber over a glass ﬂange. The latter could count theβ-rays emitted from 30 Al which were extracted fromthe RI stopping chamber and guided to the detector.
Although noise events such as from ions attached tothe electrodes or nozzle were also counted, we assumed
that the factor of the noise was small. We compared
the counts of the two plastic scintillators with diﬀerent
electric ﬁelds. Figure 3 shows the obtained extraction
eﬃciency depending on electric ﬁeld strength. This result indicates that a strong electric ﬁeld could guide theions from the exit of the oriﬁce to the detector, while
carrier gas molecules were separated. The obtained
maximum extraction eﬃciency was 4.3(1) × 10−4 .
We have been continuously investigating the conﬁguration of the electric ﬁeld, the gas pressure, and thematerials of the nozzle. In experiments with an oﬀ-line
ion source and an optimized conﬁguration, we obtained
an extraction eﬃciency as high as 4.9 × 10−3 ,3) which
was 10 times higher than the on-line result. If such aneﬃciency could be realized in the on-line experiment,
we could start the next stage of development such as
the neutralization and the spin-selection system which
are important for the RIABR system.

Fig. 1. Electric ﬁeld of drift eﬃciency measurement.2)
Fig. 3. Measured extraction eﬃciency. Electric ﬁeld waslimited to 44 V/cm because of discharge.

References

Fig. 2. Experimental setup of extraction eﬃciency measurement.
∗1∗2

Department of Physics, Tokyo Institute of Technology
Department of Physics, Rikkyo University

1) K. Shimada et al.: RIKEN Accel. Prog. Rep. 37, 175(2004).
2) H. Miyoshi et al.: RIKEN Accel. Prog. Rep. 38, 166(2005).
3) D. Nagae et al.: RIKEN Accel. Prog. Rep. 38, 159(2005).

163

RIKEN Accel. Prog. Rep. 38 (2005)

Development of linear rf trap for multireflection
time-of-flight mass spectrometer
Y. Ishida, M. Wada, H. Wollnik,∗ and Y. Yamazaki
Using a multireﬂection time-of-ﬂight mass spectrometer (MR-TOF)1) we plan to measure masses of various short-lived nuclei, which will be provided at theslow RI-beam facility (SLOWRI) of RIKEN-RIBF.2)
At SLOWRI, energetic RI-beams from the projectile fragment separator BigRIPS are decelerated andcooled in an rf ion guide and extracted as a lowenergy bunched RI-beam through an rf sextupole ion
beam guide (SPIG).3) Although a small emittance of≤ 10 eV·µs of this pulsed beam is expected, ions must
be well conﬁned in the phase space to ensure a muchsmaller emittance of ∼0.1 eV·µs before they can be injected into the MR-TOF. While the MR-TOF cancompensate the residual energy spread when the geometry and the potentials of the mirror electrodes arechosen properly,4) a smaller initial energy spread anda smaller emittance of ions improve the total performance. Therefore, it is necessary to place an ion trap
as a cooling and bunching device between the SPIG
and the MR-TOF as shown in Fig. 1. Here we report on an improved experimental result using the ion
trap device in addition to the previously reported MRTOF setup5) where an electron impact ion source was
directly connected to the spectrometer.
There are two types of possible ion trap, a linear quadrupole ion trap and a circularly symmetricquadrupole trap. We chose a linear ion trap since its
loading and extraction eﬃciency is 80% and higher
than that of the circularly symmetric trap (15%) asreported by Clark et al.6)
To eﬃciently load the pulsed ions from the SPIG
and extract most of the ions from the trap without
any collisions with gas molecules, our linear ion trap isdivided into the loading section (b) and the extraction
section (d) as shown in the inset of Fig. 1. The voltageof the endcap (a) of the trap is switched to load thepulsed ions. Ions are cooled by gas collisions with a
He buﬀer gas of 1×10−3 Torr, and distributed in frontof the grid (c) according to a potential formed by thevoltage of segmented rods and the grid. We determined
the appropriate operating parameters of this ion trapby numerically simulating the ion trajectories using
SIMION.7)
For the oﬀ-line tests of the MR-TOF with the linear
trap, an electron impact ion source was attatched tothe endcap. Stable nuclear ions were produced in theion source, extracted by an electric ﬁeld of ∼5 V/mm
and stored in the loading section of the trap. The
cooled ions were transferred to the extraction section
by switching the potential of the grid. The ions werelongitudinally compressed by further cooling in the extraction section. The well-conﬁned ions were extracted
by an electric ﬁeld of ∼100 V/mm and then accelerated to 1500 eV. This linear trap provided ion pulsesof < 10 ns duration with a repetition rate of 500 Hz.
Figure 2 shows the mass spectrum after the time

Fig. 2. Mass spectrum of CO-N2 mass doublet after flighttime of ≈4.8 ms.

Fig. 1. Schematic drawing of overview of mass measurement system. The inset shows an enlargement of
the linear RF trap, (a) an endcap, (b) a 25-mm-long loading section, (c) a grid, and (d) a 5-mm-longextraction section.
∗

164

University of Giessen, Germany

of ﬂight of ≈4.8 ms using CO ions with a mass of
27.9949 u and N2 ions with a mass of 28.0061 u. From
this spectrum we obtained an FWHM mass resolving
power of m/∆m ≈ 66,000 for the spectrometer, which
is much better than the previously reported value ofm/∆m = 40,000.1) Moreover, the signal-to-noise ratio
became higher.
The relative intensity of ions as a function of timeof ﬂight is shown in Fig. 3. Normalization was madeon the basis of ion intensity recorded after a single
pass. The ﬂuctuation of ion intensity during this measurement is ≈5%. Since the acceptance of MR-TOF
is smaller than the emittance of the ion source, rapid
decreases in ion intensity up to ∼20% were observed,
whereas there were almost no signiﬁcant losses after∼500 µs. This ﬁgure also shows that there was a small
increase in ion intensity when the rf voltage of the trap
was turned oﬀ during the TOF measurement period.
Further investigation of ion loss processes will be carried out.
The linear ion trap developed has improved the performance of the MR-TOF. On-line test experiments of
the MR-TOF combined with the rf ion-guide system
are planned to be performed soon.
References

Fig. 3. Recorded ion intensity as function of ion flight time
relative to intensity after one pass. Squares and crosses
denote the ion count rate at residual gas pressures of
1×10−7 as well as 3×10−8 Torr with no RF power being
applied to the ion trap when the ions were flying in the
MR-TOF. Circles denote the ion count at 3×10−8 Torrwhen RF power was applied.

1) Y. Ishida et al.: Nucl. Instrum. Methods Phys. Res. B
219–220, 468 (2004).
2) M. Wada et al.: Nucl. Instrum. Methods Phys. Res. B
204, 570 (2003).
3) S. Fujitaka et al.: Nucl. Instrum. Methods Phys. Res.
B 126, 386 (1997).
4) H. Wollnik: J. Mass Spectrom. 34, 991 (1999).
5) Y. Ishida et al.: RIKEN Accel. Prog. Rep. 36, 184(2003).
6) J. Clark et al.: Nucl. Instrum. Methods Phys. Res. B
204, 487 (2003).
7) D. A. Dahl: Int. J. Mass Spectrom. 200, 3 (2000).

165

RIKEN Accel. Prog. Rep. 38 (2005)

Development of low-energy RI transportation system withstatic electric field in Ne gas
H. Miyoshi,∗1 K. Shimada,∗1 D. Nagae,∗1 A. Yoshimi, M. Uchida,∗1 K. Asahi,∗1 H. Ueno, D. Kameda,∗1
G. Kato,∗1 S. Emori,∗1 G. Kijima,∗1 M. Tsukui,∗1 T. Haseyama, J. Murata,∗2 and Y. Kobayashi
Spin-polarized low-energy radioactive isotope (RI)
beams are useful not only in nuclear physics but also
in materials and surface physics. We are developing a device that produces a spin-polarized low-energy
RI beam on the basis of the atomic beam resonancetechnique (RIABR). A prototype, including a fragment stopping and collecting chamber, an atomicbeam forming nozzle and a spin-selecting sextupole
magnet is almost completed. At present, we are testing
the system with ions of stable isotopes injected froman ion source.1)
In this paper, we report on test experiments for the
fragment stopping and collecting chamber using an RI
beam delivered from the fragment separator RIPS.
The setup used for the test experiments is schematically illustrated in Fig. 1. In these experiments, weemployed a neon gas as a stopping gas. The RI fragment stopping and collecting chamber is made of a
glass (VIDREX). The total length of the chamber is1500 mm, and the diameter is about 50 mm. The pressure of neon gas in the chamber was approximately
600 Torr. We chose a beam of 30 Al ions producedby the fragmentation of an 40 Ar projectile at an energy of 95 A MeV on a 3.0-mm-thick Beryllium target. The beam was collimated into a diameter of approximately 10 mm at the entrance of the chamber,and the intensity of the 30 Al beam was approximately
104 particles/sec. Using a rotary degrader, we adjusted
the energy of 30 Al ions at the entrance of the chamber such that the ions were safely stopped in the Ne
gas volume. Figure 1 also shows the detector system
employed for β-ray detection. The system consistedof two layers of plastic scintillator of size 45 × 0.5 ×
390 mm and 20 × 5 × 380 mm.

We measured the β-ray counts from the radioactivities in the chamber. By comparing them with expected
counts from a simulation with GEANT code,3) we obtained the drift eﬃciency. Figure 2 shows hypothetical
RI distributions for immediately after the stopping of
the RI ions (dashed curve) and after their drift in theelectric ﬁeld is completed (solid curve), that best ﬁt thedata. The drift eﬃciency thus obtained by ﬁtting was
0.72. The measured and calculated ratios of counts for
β-rays from the stopped and drifting RIs are summarized in Table 1.
From the measured data and calculated result, thedrift eﬃciency for the 30 Al ions in a stopping gas ofneon was determined to be 0.72 ± 0.04. This value
corresponds to a mean neutralization cross section of
7.9×10−22 cm2 , assuming that the defraction eﬃciency
is negligible. The large drift eﬃciency presently obtained provides a promising prospect for realizing abright RIABR system.

Fig. 2. Assumed distributions of RI atoms. Dashed curve
indicates the RI distribution just after the stopping of
the incident RI ions. Ions reach the ﬁnal electrode (z =+20 cm) after drifting, where the eﬃciency for β-ray
counting drops abruptly due to the presence of a Pb
shield.
Table 1. Measured and calculated ratios of β-counts before
and after the drift of ions. The drift eﬃciency of 0.72
is assumed in the calculation.
ratio
Median positionof the beam [mm]Fig. 1. Schematic view of experimental setup. The cylindrical glass chamber was surrounded by an array of
20 pieces of ring electrode with an inner diameter of
50 mm. The length of drift ﬁeld is approximately
400 mm. The detailed arrangement is described elsewhere.2)
∗1
∗2

166

Department of Physics, Tokyo Institute of Technology
Department of Physics, Rikkyo University

−100
0
+200

 Drifting 
Stopping Drifting 

exptStopping

0.98 ± 0.08
0.85 ± 0.05
0.95 ± 0.07

0.962
0.846
0.969

calc

References
1) D. Nagae et al.: RIKEN Accel. Prog. Rep. 38, 159(2005).
2) K. Shimada et al.: RIKEN Accel. Prog. Rep. 38, 163(2005).
3) GEANT3: Detector Description and Simulation Tool
(CERN, Geneva, 1993).

RIKEN Accel. Prog. Rep. 38 (2005)

Confinement of large number of antiprotons and production ofultraslow antiproton beam
N. Kuroda,∗1 H. A. Torii,∗1 K. Yoshiki Franzen,∗1 Z. Wang,∗1 S. Yoneda,∗1 M. Inoue,∗1 M. Hori,∗2 B. Juhász,∗3
D. Horváth,∗4 H. Higaki,∗5 A. Mohri, J. Eades,∗6 K. Komaki,∗1 and Y. Yamazaki∗1
We have succeeded in storing a large number ofultraslow antiprotons, which is an important step insynthesizing antihydrogen (pe+ )1,2) and antiprotonic
atoms (pA+ ). Such exotic atoms can only be eﬃciently
synthesized from component particles at eV and lower
energy scales, which is far below the mandatory GeV
scale of accelerator-produced antiprotons.
At CERN, the Antiproton Decelerator (AD) supplies a 5.3 MeV antiproton beam. This beam energy
is, however, still far above the 10 keV range at which
antiprotons can readily be captured and cooled in electromagnetic traps. Although degrader foils are usuallyused to reduce the antiprotons energy further from the
MeV to keV scale,3–5) here the simple degrader foils
were replaced by a Radio Frequency Quadrupole Decelerator (RFQD).6,7) Thin PET foils, instead of relatively thick foils located upstream of a multiring trap
(MRT),8) were used to isolate the trap and RFQD vacuum systems. Because the antiprotons were to spend
a long time in the trap, more stringent vacuum conditions were required there than in the RFQD to avoid
antiproton loss by annihilation on residual gas atoms.
The MRT comprises several ring electrodes lying on
the axis of a superconducting solenoid. Before the antiprotons arrived, an electron plasma was preloaded in
the trap allowed to reach equilibrium, where its shapewas expected to be spheroidal. This electron plasma
continuously cooled the newly arrived antiprotons,
since the thermal energy it received from the antiprotons was spontaneously dissipated by synchrotron radiation in a strong magnetic ﬁeld with a time constantof about one second.5,9) Approximately 1.2 × 106 p̄s
could be stored and cooled in the MRT per AD shot.
This ﬁgure is ∼50 times higher than the best values
obtained with thick degrader foils.10) By stacking ﬁve
AD shots in sequence,10) ≈ 5 million antiprotons, thelargest number of antiprotons ever stored and cooled,were conﬁned in our MRT.
The joint plasma modes were observed before and after antiproton injection, which allowed us to monitor
the plasma shape, density, and temperature variations
nondestructively.11) We excited axially symmetric elec∗1
∗2
∗3
∗4
∗5
∗6

Institute of Physics, University of Tokyo
Organisation Européenne Pour la Recherche Nucléaire(CERN), Switzerland
Institute of Nuclear Research of the Hungarian Academy of
Science, Hungary
KFKI Research Institute for Particle and Nuclear Physics,
Hungary
Plasma Research Center, University of Tsukuba
Department of Physics, University of Tokyo

trostatic oscillation (l, 0) modes (l = 1–4) of the joint
plasma by applying pulsed white noise. The shift ofthese mode frequencies with time was used to monitor the antiproton cooling process. Using the observed
ωl -values (l = 2, 3, and 4) before antiproton injection
and the electron number previously measured under
the same conditions, the temperature-dependent dispersion relation for a cold spheroidal plasma12,13) canbe solved to give the plasma density ne and the aspectratio α. Using ne and α so obtained, the temperature Te after antiproton injection was evaluated fromωl , which indicated a maximum plasma temperaturerise of ≈ 0.6 eV. The variations of the plasma frequencies during the cooling that followed heat transfer from the antiprotons were consistently reproduced
by solving rate equations which took into account thesynchrotron radiation cooling of electrons with a time
constant of ∼ 6/(B[T])2 s and the energy transfer between antiprotons and the electron plasma.13)
The antiprotons were then continuously extracted
from the MRT by ramping the trap potential. Theenergy range of the extracted antiprotons was 10 eV–
250 eV. This ultraslow antiproton beam will be used
for future studies such as the investigations of antiprotonic atom formation processes under the singlecollision condition14) and of antiproton magnetic moment with H̄ beams.15)
References
1) M. Amoretti et al.: Nature 419, 456 (2002).
2) G. Gabrielse et al.: Phys. Rev. Lett. 89, 213401 (2002);
Phys. Rev. Lett. 89, 233401 (2002).
3) G. Gabrielse et al.: Phys. Rev. Lett. 57, 2504 (1986).
4) M. H. Holzscheiter et al.: Phys. Lett. A 214, 279(1996).
5) G. Gabrielse et al.: Phys. Rev. Lett. 63, 1360 (1989).
6) A. M. Lombardi, W. Pirkl, and Y. Bylinsky: Proc.
2001 Particle Accelerator Conf., Chicago, USA, 20016 (IEEE, 2001), p.585.
7) M. Hori et al.: Phys. Rev. Lett. 91, 123401 (2003).
8) A. Mohri et al.: Jpn. J. Appl. Phys. 37, 664 (1998).
9) B. R. Beck, J. Fajan, and J. Malmberg: Phys. Plasmas
3, 1250 (1996).
10) G. Gabrielse et al.: Phys. Lett. B 548, 140 (2002).
11) H. Higaki and A. Mohri: Phys. Lett. A 235, 504(1997).
12) M. D. Tinkle et al.: Phys. Rev. Lett. 72, 352 (1994).
13) H. Higaki et al.: Phys. Rev. E 65, 046410-1 (2002).
14) Y. Yamazaki: Nucl. Instrum. Methods Phys. Res. B
154, 174 (1999); Hyperfine Interact. 138, 141 (2001).
15) A. Mohri and Y. Yamazaki: Europhys. Lett. 63, 207(2003).

167

RIKEN Accel. Prog. Rep. 38 (2005)

Development of collinear laser spectroscopy setup for Ni isotopes
M. Wada, V. Lioubimov,∗1 M. D. Gardner, A. Takamine,∗2 T. Nakamura,∗3 Y. Ishida, K. Okada,∗4
H. Iimura,∗5 H. A. Schuessler,∗1 and Y. Yamazaki∗2
The root-mean-square charge radii of unstable nuclei have been determined exclusively by the isotope
shift (IS) measurements of the optical transitions of
singly charged ions or neutral atoms by laser spectroscopy. Many isotopes of alkaline, alkaline earth andnoble gases, which all have good optical transitions andare available at conventional ISOL facilities, have beenmeasured by collinear laser spectroscopy. However, theisotopes of other elements have not been widely investigated mainly because their beams have been diﬃcult
to be obtained.
A new facility for slow radioactive ion beams(SLOWRI) is being developed1) at the RIKEN radioactive ion beam factory (RIBF). SLOWRI aims toprovide universal slow RI beams of high purity andsmall emittance with high-energy RI beams from a
projectile fragment separator being slowed down to
low energies and cooled in an rf ion guide. Since inthese production, separation and cooling schemes there
are no chemical processes, in principle, the isotopesof all atomic elements will be provided as pure, monoenergetic, small emittance, and low-energy beams.
It should expand the range of applicable nuclides oflaser spectroscopy. In the ﬁrst few years of the RIBF
project, Ni and its neighboring elements, such as Ni,
Co, Fe, Cr, Cu, Ga and Ge, will be investigated.
They all have possible optical transitions in the groundstates of neutral atoms with presently available laser
systems. The expected beam intensities of these isotopes at SLOWRI is shown in Fig. 1, together withpossible resonant wavelengths for charge radius measurements.

Fig. 1. Expected isotopes of Ni and their neighborhood.
Possible resonant wavelengths of neutral atoms are also
depicted on the right-hand side.
∗1
∗2
∗3
∗4
∗5

168

Department of Physics, Texas A&M University, USA
Graduate School of Arts and Science, University of Tokyo
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Department of Physics, Sophia University
Japan Atomic Energy Research InstituteWe set Ni isotopes as the ﬁrst candidates to be investigated at SLOWRI. The level diagram of Ni atoms
for a resonance ionization scheme is shown in Fig. 2.
The 323.293 nm s-p transition from the ground state
4s a3 F4 to the excited state 4p z 3 G5 will be used to determine the volume eﬀect of the IS. This transition canbe excited numerous times for atoms ﬂying in the interaction region. In this excitation scheme an electronin the J = 4 state is excited to the J  = 5 state, thenthe electron can decay only to the J = 4 state, so thatthe electron can be excited again by the same laser radiation. This scheme notably enhances the sensitivityof spectroscopy. A ﬂuorescence photon can be used
to detect the resonance; however, the sensitivity ofsuch photon detection is still limited. This usually requires an ion beam intensity of > 104 atoms/s. To improve the sensitivity, we will use a resonance ionization
method that utilizes two more laser radiations, namely,
the 511 nm radiation provided by a DISK laser with acontinuous beam power of ∼5 W that excites from the
4p z 3 G5 state to the 5s f 3 F4 state and the ∼898 nm
radiation provided by a titanium sapphire laser that
excites to the Rydberg level. An external electric ﬁeld
can ionize Rydberg atoms, and then, the ion and theelectron can be detected coincidentally with high sensitivity and low background. In this way, the resonancein the s-p transition can be detected even though thebeam intensities are as low as 10 atoms/s.
In year 2004, a setup for oﬀ-line test experiments ofcollinear laser spectroscopy was installed with a collaboration with Texas A&M University. An ion source
for test experiments will be installed in year 2005 andoﬀ-line tests will be started.

Fig. 2. Level scheme for three-step resonance ionization of
Ni atoms.

Reference
1) M. Wada et al.: Nucl. Instrum. Methods Phys. Res. B
204, 570 (2003).

RIKEN Accel. Prog. Rep. 38 (2005)

Magneto-optical rotation eﬀect in Rb for EDM experiment
A. Yoshimi, K. Asahi, S. Emori,∗ M. Uchida,∗ and S. Oshima∗
A nuclear spin maser with 129 Xe operated at a low
static ﬁeld of 30 mG has been developed,1) with which
the spin precession frequency can be measured withhigh precision. Such a device can be utilized to search
for the permanent electric dipole moment (EDM) of
the atom, when it is installed with a high-performancemagnetic shield and high-precision magnetometer. In
the previous report, the design and construction of the
4-layer magnetic shield was reported.2) Here, we reporton the development of the atomic magnetometer that
we have recently commenced.
The magneto-optical rotation eﬀect is known to beenhanced when the light frequency is tuned to near
the atomic absorption line. Recent studies on themagneto-optical rotation eﬀect with an alkali vapor
cell indicate that the sensitivity of the magnetometerbased on this eﬀect√can in principle reach a shot-noise
limit of ∼10−12 G/ Hz.3) The origin of the optical rotation is the diﬀerence in refractive index between leftand right-circular polarized light in the sample when amagnetic ﬁeld is applied. Therefore, this leads to therotation angle φ having a dispersive-shaped magneticﬁeld dependence.
The experimental setup is shown in Fig. 1. The
cylindrical glass cell conﬁning Rb vapor was located inside the 3-layer magnetic shield. A laser beam emitted
from a laser diode with a single frequency mode passes
through the cell, a linear polarizer, and a photoelastic
modulator (PEM), and detected with a photodiode.
The wavelength of the single-mode laser is tuned to

the D1 absorption line of the Rb atom, which is being
monitored by the absorption-induced emission fromthe reference cell the split laser beam passes through(photograph in Fig. 1). The small optical rotation of
the linear polarization (φ  1) can be described as achange in the polarization component along a direction perpendicular to the initial polarization direction.
The PEM modulates the retardation of the light phase(from −π to +π) only in the modulating plane, so thatthe nonzero component of the light polarization along
the axis perpendicular to the modulating axis causesa modulation of the direction of the light polarization.
Therefore, the transmitted light intensity after passing
through the linear-polarizing ﬁlter is modulated. The
small optical rotation can be observed by phase sensitively detecting the signal using the photodiode witha lock-in ampliﬁer, as shown in Fig. 1. A magnetic
ﬁeld was applied with the solenoid magnet wound inside the magnetic shield. Figure 2 shows the typicallymeasured optical rotation signal with a commercial Rbvapor cell obtained by sweeping the magnetic ﬁeld over
the range of 0–3 G, which has a dispersive shape. We
are now calibrating the rotation angle with precise control of a λ/2 plate. We are also investigating the dependence of the rotation signal on various parameters,such as laser power, cell temperature, and the innercoating of the cell wall, in order to explore its performance for application to the magnetometer.

Fig. 2. Typically measured optical rotation signal.

References

Fig. 1. Experimental setup for measuring optical rotationin Rb cell.

∗

1) A. Yoshimi et al.: RIKEN Accel. Prog. Rep. 36, 173(2003).
2) A. Yoshimi et al.: RIKEN Accel. Prog. Rep. 37, 160(2004).
3) D. Budker et al.: Phys. Rev. A 62, 043403 (2000).

Department of Physics, Tokyo Institute of Technology

169

RIKEN Accel. Prog. Rep. 38 (2005)

Nondestructive intensity monitor for cyclotron beams
M. Wada, Y. Ishida, T. Nakamura,∗1 A. Takamine,∗2 A. Yoshida, and Y. Yamazaki∗2
For any experiments that use beams of an accelerator, monitoring the beam intensity is always an important concern. It is particularly useful if one cancontinuously measure the beam current without disturbing the beams. Counting elastic scattering particle from the target is often used for such a purpose,
however, the dynamic range of measurable beam intensity is limited and the calibration often changes fordiﬀerent experimental conditions.
We report here on the test experiments for a nondestructive current monitor of cyclotron beams using a
toroidal pulse transformer. The principle of the transformer detector is shown in Fig. 1. The cyclotron beam
is a single-turn “coil” of the primary side of the transformer which induces a magnetic ﬂux in the toroidal
core, then it induces a current in the secondary coil. In
case a secondary coil of 5 turns is used, the transformer
yields a nominal signal amplitude of

−1
1
1
Ibeam
+
= 5 Ω × Ibeam (1)Vsig =
5 turns 50 Ω 50 Ωat the 50 Ω input of the ampliﬁer. The sensitivity of
5 nV/nA, is quite low to be measured in a noisy environment. However, since the beams from the cyclotron
are a chain of short pulses with a constant repetition
rate of ≈ 50 ns, synchronous detection with a spectrum
analyzer or a lock-in ampliﬁer can discriminate such a
low-amplitude signal from the noise.
We used a Fast Current Transformer manufactured by BERGOZ Instrumentation, France.1) The
transformer, model FCT-082-05:1-H-INS, consists of a
toroidal core made of cobalt-based nanocrystalline andamorphous alloys of 82 mm inner diameter and a ﬁveturn coil wound by the proprietary multithread technique. The bandwidth of the FCT is 32 kHz∼700 MHz
and the typical rise time is 500 ps. The fast response of
the detector allows us to observe the higher harmon-

ics of the pulsed beam. Since the duty cycle of thecyclotron beam is very low, typically < 1/100, it generates many harmonics and the higher order harmonics
have almost the same power as the fundamental one.
It is advantageous to observe higher order harmonics,
since the ambient noises are in general decreases withincreasing frequency.
The FCT is placed in the E6 beamline of RIKEN
ring cyclotron. In order for the transformer to “see”
a current passing through its center, the wall current
imaging the ion beam must be diverted around theoutside of the device. The beam pipe of 63.5 mm diameter is electrically interrupted by a PEEK sleeve for
4 mm width and the FCT is mounted close to the gap(Fig. 2). An aluminum box covers the FCT for electrostatic shielding as well as for electrical connection
between the interrupted beam pipe outside of the FCT.
The signal from the FCT is directly transported by acoaxial cable, SUHNER S10162B-11, for 70 m to thespectrum analyzer Tektronix 3056 or the lock-in ampliﬁer, Stanford Research Systems SRS844, at control
room J4.
Test experiments are performed using a cyclotron
beam of 100 A-MeV 13 C6+ with various beam intensities. Figure 3 shows a power spectrum of the second harmonics of the 14.5 MHz pulsed beam measured
by the spectrum analyzer. In this measurement, thecyclotron beam was chopped with a 10 Hz repetition
cycle so that sidebands at ±10 Hz were also observed.
The background level here was ∼ −115 dBm which corresponds to 0.4 µV ≈ 80 nA, which is not suﬃciently
small to observe low-intensity beams.
Use of a lock-in ampliﬁer is more suitable for measurements of the absolute value of the current. A measurement for various intensities of ∼400 nA to ∼3 nA
using the lock-in ampliﬁer is shown in Fig. 4. The
cyclotron beam was chopped with 0.01 Hz and a duty
cycle of 50% to enhance visibility. The rf signal of theFig. 1. Schematic diagram of toroidal current monitor. The
beam current passing through the toroidal core is equivalent to the current in a one-turn coil.
∗1
∗2

170

Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Institute of Physics, Graduate School of Arts and Science,
University of Tokyo

Fig. 2. Mechanical drawing of FCT monitor housing.

Fig. 3. Power spectrum of second harmonics of 100 A-MeV
13 6+
C
beam of 800 enA detected by FCT. Sidebands
due to a chopped beam with 10 Hz as well as the carrier
signal at ∼29 MHz are observed.

cyclotron was used for the reference signal of the lockin ampliﬁer with the ‘×2’ mode which corresponds tothe second harmonics. Here, the background signal
was as low as ≈ 40 nV, which enabled us to measuresuch a low-intensity beam of 3 nA.
The proportionality of the FCT signals with a background subtraction to the Faraday cup measurements
preserved for wide range of intensity (Fig. 5). The
gain factor and the background voltage obtained were
6.49(4) nV/nA and 39(1) nV, respectively.
Adjustment of the phase is essential for obtaining such a low background condition. The absolute amplitude of the output signal (dBm) was aslarge as ∼0.45 µV even in the beam-oﬀ period, which
was mainly caused by a large phase-oﬀ component
Y = −0.45 µV, while the phase-on component was
X = 0.04 µV. This large oﬀ-phase signal, but still
synchronized to the cyclotron beam frequency, is supposed to be due to the rf signal of the cyclotron which
may come along the beam transport line. It can be a
problem if the beam bunch and the rf noise signal coincide with each other. However, such a condition should
be avoided by moving the location of the FCT, since
the beam velocity (∼ 0.5c) and the traveling velocityof the rf signal should diﬀer.
The authors thank Mr. Julien Bergoz for useful discussions.

Fig. 5. ‘On-phase’ voltage of lock-in amplifier signal vs.
beam current measured at Faraday cup. Insert is anenlarged graph for lower intensities. The fitting line is
y = 6.49(4) · x + 39(1) × 10−9 .
Fig. 4. Cyclotron beam intensities measured at Faraday
cup and voltages of lock-in amplifier for various intensities. The time constant for the lock-in amplifier was
300 ms except for the last 5 peaks, which were at 1 s (3peaks) and 3 s (2 peaks).

Reference
1) BERGOZ Precision Beam Instrumentaion: Fast Current Transformer User’s Manual.

171

RIKEN Accel. Prog. Rep. 38 (2005)

Beam test of magnetic spectrograph PA
N. Iwasa,∗1 S. Kubono,∗2 Y. Fuchi,∗3 H. Fujikawa,∗2 N. Fukunishi, J. J. He,∗2 S. Kato,∗4 J. Moon,∗2
M. Notani,∗2 A. Saito,∗2 T. Teranishi,∗2 M. H. Tanaka,∗3 N. Yamazaki,∗2 and Y. Wakabayashi∗2
Beam test experiments of the high-resolution magnetic spectrograph PA,1) which was installed at theE2 experimental hall,2) were performed. The aim of
the experiments was to study achromatic beam transportation (ABT) and dispersion matching transportation (DMT) from the ring cyclotron to PA. To determine excitation energies with a resolution of 100 keV
in FWHM in (4 He,8 He) reactions with a 135 MeV
α beam, a momentum resolution less than 0.04% in
FWHM is needed.
An α beam at 104 MeV accelerated by the ring cyclotron was transported to the target position of PA
with ABT, and bombarded a 1-µm-thick gold target.
PA was set at 10 degrees, and a slit was placed for
restricting the solid angle to 0.1 msr. The momentaof scattered α particles were measured by a hybrid
position-sensitive gas proportional counter (GPC)3)
with an active area of 400×35 mm2 located on the focal
plane of PA. The ∆E and the time of ﬂight were measured by a plastic scintillator with a thickness of 2 mm
placed behind GPC. The momenta were calibratedusing the α particles with four diﬀerent magnetic ﬁeld
settings of PA, ∆B/B0 = −0.746%, 0%, 0.898%, and1.804%. The momentum resolution was measured tobe 0.1% in FWHM, although the intrinsic momentum
resolution of PA is 0.01% using the target spot size of
1 mm.1) Since the momentum resolution is larger than
the required one, DMT is desired.
As a ﬁrst step of the DMT study, a stainless-steel
target with a hole of 1 mm φ instead of the gold target
was bombarded by a faint α beam, and PA was set
at 0 degrees. The target thickness is suﬃcient to stop
the beam in the target. The position of the hole could
be selected to be −5, 0, and +5 mm in the horizontal
direction from the optical axis. The hole at 0 mm wasused during this experiment. Several parameters forthe beam transport line for DMT were tested.
The solid curve in Fig. 1 shows relative momentum spectra in ABT measured by GPC. The momentum resolution in ABT was measured to be 0.03% in
FWHM, which is better than that of 0.1% measured
at 10 degrees with the 1-µm-thick gold target. The
momentum spread caused by energy straggling in thegold target was measured to be 0.03%, which agrees
with the calculated energy straggling of 0.054 MeV.
The remaining momentum spread of 0.08% observed
at 10 degrees with a higher beam intensity was not
∗1
∗2
∗3
∗4

172

Department of Physics, Tohoku University
Center for Nuclear Study, University of Tokyo
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Department of Physics, Yamagata University

Fig. 1. Normalized momentum spectrum. The solid curve
and the hatched area denote momentum distributionsin achromatic beam transportation and dispersive beamtransportation, respectively. Note that in the dispersive beam transportation, the momentum width wasselected to be 0.01% using a dispersively focused beamand 1-mm-φ hole.

understood. Since a 0.1 msr slit was used for PA, themomentum spread caused by the kinematics was negligible.
The hatched area in Fig. 1 shows a normalized momentum spectrum when the beam was focused dispersively on the target. The momentum resolution wasmeasured to be 0.02% in FWHM. Note that the momentum width of the beam was selected to be 0.01%(full width) using a dispersively focused beam on thetarget and a 1-mm-φ hole. This selected momentum
width was estimated from the calculated dispersion
from the ring cyclotron to PA and the hole size. The
measured momentum resolution is slightly larger thanthe calculated intrinsic momentum resolution of PA.
The present momentum resolution was considered tobe the best resolution measured in the RIKEN accelerator research facility, encouraging us to study dispersion matching with the spectrograph PA.
Further investigations for dispersion matching are
required before studying the (4 He,8 He) reactions, because their cross sections are so small. However, thepresent test results indicate that the spectrograph PA
can be used for the measurement of reactions that haverelatively large cross sections, for example, (4 He,6 He)reactions, with a limited target size.
References
1) S. Kato, M. H. Tanaka, and T. Hasegawa: Nucl. Instrum. Methods Phys. Res. 154, 19 (1978).
2) N. Yamazaki et al.: CNS Rep. 2000, 14 (2001).
3) M. H. Tanaka, S. Kubono, and S. Kato: Nucl. Instrum.
Methods Phys. Res. 195, 509 (1982).

RIKEN Accel. Prog. Rep. 38 (2005)

Low-energy radioisotope beam separator CRIB†
Y. Yanagisawa, S. Kubono,∗1 T. Teranishi,∗2 K. Ue, S. Michimasa, M. Notani,∗3 J. J. He,∗1
Y. Ohshiro,∗1 S. Shimoura,∗1 S. Watanabe,∗1 N. Yamazaki,∗1 H. Iwasaki,∗4 S. Kato,∗5 T. Kishida,
T. Morikawa,∗2 and Y. Mizoi∗6
Radioactive isotope (RI) beams at 5–10 MeV/
nucleon are very useful for nuclear spectroscopy studies, such as particle transfer reactions. Nuclear structure studies with in-beam γ-ray spectroscopy in thisenergy region, are also powerful, because nuclear fusion reactions have large cross sections.
A low-energy in-ﬂight-type RI beam separator,
called CRIB, was installed in the experimental hall
E7 at RARF for nuclear physics and nuclear astrophysics by the Center for Nuclear Study (CNS).1) This
separator was developed under the CNS-RIKEN collaboration. It consists of a double achromatic system and Wien ﬁlter. It also consists of the majorparts previously used for the spin transfer spectrometer DUMAS2) at the Research Center for Nuclear
Physics (RCNP), Osaka University, and several modiﬁcations and new installations were made. It comprises
a windowless gas target,3) a velocity ﬁlter (Wien ﬁlter)and high-power Faraday cups on inner dipole walls.
The double achromatic part of CRIB, the ﬁrst half,consists basically of four components: a production
target, two dipole magnet systems, and an energy degrader placed in between. It was designed to provide
RI beams of 5–10 MeV/nucleon. Its compact design
matches the layout of the experimental hall. A degrader of uniform thickness was adopted because it iseasy to fabricate and the thickness can be accurately
controlled. In addition, we constructed a velocity ﬁlter
section, the second half, for better isotone separation.
During the installation of CRIB, we also renewed
the beam line from the AVF cyclotron for better transport eﬃciency, and installed a 14 GHz ECR ion source,called Hyper ECR.4) The primary beam intensity wasincreased by one to two orders of magnitude at the pro-

†
∗1
∗2
∗3
∗4
∗5
∗6

duction target, F0, resulting in more intense RI beam
production. Recently, we have obtained an RI beam
intensity of about 1 × 106 from (p,n) reactions. Thisvalue will be further increased in the near future by
improving the performance of the ion source and theacceleration eﬃciency of the AVF cyclotron, as wellas using target technology. Therefore, CRIB has agood prospect for experimental studies in both nuclear
physics and nuclear astrophysics, as well as for otherapplications.
Current experimental programs at CRIB include(1) resonant elastic scattering experiments for nuclear
structure and nuclear astrophysics studies, (2) measurements of reaction cross sections of astrophysicalinterest, and (3) γ-ray spectroscopy via fusion reactions. Several experiments at CRIB have already been
performed successfully using 11 C, 14 O, 17 N, 22 Mg and23
Al beams.5–8)
References
1) Y. Yanagisawa et al.: RIKEN Accel. Prog. Rep. 34, 183(2003).
2) T. Noro et al.: J. Phys. Soc. Jpn. 55, 470 (1986).
3) T. Kishida et al.: Nucl. Instrum. Methods Phys. Res. A
438, 70 (1999).
4) Y. Ohshiro et al.: RIKEN Accel. Prog. Rep. 36, 279(2003).
5) T. Teranishi et al.: RIKEN Accel. Prog. Rep. 35, 73(2002).
6) M. Notani et al.: RIKEN Accel. Prog. Rep. 36, 64(2003).
7) A. Odahara et al.: RIKEN Accel. Prog. Rep. 37, 75(2004).
8) J. J. He et al.: RIKEN Accel. Prog. Rep. 37, 68 (2004).

Condensed from the article in Nucl. Instrum. Methods Phys.
Res. A 539, 74 (2005)
Center for Nuclear Study (CNS), University of Tokyo
Department of Physics, Kyushu University
Argonne National Laboratory, USA
Department of Physics, University of Tokyo
Department of Physics, Yamagata University
Osaka Electro-Communication University

173

RIKEN Accel. Prog. Rep. 38 (2005)

Performance of SAMURAI spectrometer in the QQQ-D mode
Y. Sasamoto,∗1 T. Uesaka,∗1 T. Kawabata,∗1 T. Kobayashi,∗2 and T. Nakamura∗3
A large acceptance spectrometer SAMURAI1) is
planed to be installed at RIBF. It is a superconducting dipole magnet with a circular pole of 1 m radius.
The pole gap is 80 cm and the maximum magnetic
ﬁeld is 3 T. The spectrometer will be mainly used forspectroscopic studies of unstable nuclei with radio active beams. Several experiments concerning few body
physics using a 880-MeV primary deuteron beam arealso proposed. Such experiments require high momentum resolution of ∆p/p  3 × 10−4 , angular resolutionof ∆θ  3 mr, and solid angle of ∆Ω  6 msr for 880MeV deuteron, whose magnetic rigidity Bρ is 6.7 Tm.
In the original operation mode of SAMURAI, only
the dipole magnet is used to analyze charged particles emitted from the reaction target. It is, however,diﬃcult in this mode to achieve the high resolution
required in the few-body experiment because horizontal focus can not be achieved at the detector position for particles with Bρ = 6.7 Tm. To improve themomentum resolution, a new operation mode of the
SAMURAI spectrometer is studied. In the new operation mode, a triplet quadrupole magnet2) in the beamline is used in combination with the dipole magnet
to analyze charged particles emitted from the target.
The quadrupole triplet consists of the superconducting
magnets with the warm bore radius is 12 cm.
In present study, the exit of the third quadrupole
magnet (Q3) is located at 3.5 m upstream from the center of the dipole magnet. The target position should
be close to the entrance of the ﬁrst quadrupole magnet(Q1) as much as possible to obtain large acceptance.
The target position is ﬁxed at 0.8 m upstream from theentrance of the Q1. The focal plane is 3 m downstream
from the center of the dipole magnet.
The computer code GIOS3) is used to calculate theparticle trajectories in the magnet system. Figure 1
shows the layout of the spectrograph in the QQQ-D operation mode. The particle trajectories obtained fromthe ﬁrst order calculation are also shown in Fig. 1.
Many combinations of three quadrupole ﬁelds are
examined to achieve both good resolution and large
acceptance simultaneously. Figure 2 shows one of therealistic solution. The ion optical properties obtained
from the ﬁrst order calculation are summarized in Table 1, while the magnetic ﬁeld strengths are shown in
Table 2. The angular acceptance is limited by the aperture of Q1. In Table 1, the acceptance is approximatedby an elliptical shape not a rectangle shape. From thepresent study, it is found that the momentum reso∗1
∗2
∗3

174

Center for Nuclear Study, Graduate School of Science, University of Tokyo
Department of Physics, Tohoku University
Department of Physics, Tokyo Institute of Technology

Fig. 1. Schematic layout of the SAMURAI spectrometerin the QQQ-D mode. Q1, Q2 and Q3 are quadrupole
magnets, while SAMURAI is a dipole magnet. The
particle trajectories with δ = ±3% and θ = ±20 and
0 mr are drawn.

Fig. 2. Particle trajectories in the SAMURAI spectrometerin the QQQ-D mode. The trajectories with x = ±1 mm,
y = ±1 mm, θ = ±20 and 0 mr, φ = ±90 and 0 mr, andδ = ±3% are drawn. The top figure shows trajectories
on the horizontal plane, while the bottom figure shows
those on the vertical plane.
Table 1. Ion optical properties of the SAMURAI spectrometer in the QQQ-D mode obtained from the firstorder calculation.
bending angle
(x|x)
(x|δ)
(y|y)
(y|b)
Resolving Power§
Angular acceptance (horizontal)
Angular acceptance (vertical)
Solid angle (ellipse)§

48.5◦−0.4602.249 m−13.36−2.886 m/rad
4.889 m
±20 mr±90 mr
5.7 msr(x|δ)
Resolving Power = |(x|x)|

Table 2. Magnetic field strengths of the SAMURAI spectrometer in the QQQ-D mode.
Q1
Q2
Q3
SAMURAI−0.083 T/cm
0.912 T/cm
0.108 T/cm
3.0 T

lution of ∆p/p  2 × 10−4 , the angular resolution of∆θ  5 mr, and the solid angle of ∆Ω  6 msr are expected in the ﬁrst order calculation if the beam spot
size is assumed to be 1 mm.
The eﬀect of the fringing ﬁeld is neglected in thepresent study. The third order calculation taking thefringing ﬁeld into account is in progress.

mittee 2004-11, unpublished.
2) T. Kubo: Nucl. Instrum. Methods Phys. Res. B 204,
97 (2003).
3) H. Wollnik et al.: Proc. 7th Int. Conf. on Atomic Masses
and Fundamental Constants (AMCO-7), DarmstadtSeeheim, Germany, 1984-9, edited by O. Klepper(Lehrdruckerei, Darmstadt, 1984), p. 705; GSI Report,
THD-26, 679 (1984).

References
1) T. Kobayashi et al.: RIBF International Advisory Com-175

RIKEN Accel. Prog. Rep. 38 (2005)

Development of TOF spectrometer for use in experiments at RIPS
N. Aoi, E. Takeshita,∗1 H. Suzuki,∗2 S. Ota,∗3 T. Kubo, S. Takeuchi, K. Ieki,∗1 H. Iwasaki,∗2 K. Kusaka,
H. Sakurai,∗2 S. Shimoura,∗4 T. Motobayashi, and K. Yoshida
A variety of unique structures have been revealed using the in-beam γ-ray spectroscopy technique with unstable nuclear beams. These studies have thus far been
performed mainly in the mass region smaller than 40.
The limitation on the mass region is mainly due to thediﬃculties of particle identiﬁcation (PID) of scatteredions. The time-of-ﬂight (TOF) spectrometer is being
developed to extend the in-beam γ-ray spectroscopy
study at RIPS toward the heavier mass region up toA ∼80 by improving the PID resolution.
The TOF spectrometer is designed to have a
PID resolution of ∼1.4% (FWHM) by combining
high-energy-resolution Si detectors and high-TOFresolution plastic scintillators with a long ﬂight path(∼4 m). The atomic number (Z) is determined from
TOF and ∆E using the relation ∆E ∝ Z 2 TOF2 , andthe mass number (A) is determined from the TOF andE using the relation E ∝ A/TOF2 . Z and A resolutions of 0.7% and 1.4% (FWHM) are expected, assuming the relative resolutions for TOF, ∆E, and E to
be 0.5% (250 ps/50 ns), 1.0%, and 1.0%, respectively.
This PID resolution is much higher than the PID resolution obtained by the Si ∆E-E method (typically2.5%) or TOF-∆E-E method using plastic scintillator
hodoscopes (typically 3.7%).
Besides the PID resolution, large angular and momentum acceptances are required, because the intensity of the beam to be used with the TOF spectrometer is very weak. Therefore, to avoid the dispersion of nuclei when they pass through the long ﬂight
path, the Superconducting Triplet Quadrapole magnet(STQ) (Fig. 1) is incorporated as a focusing element.
The STQ1) was developed as a prototype magnet for
BigRIPS,2) and thus, has a large bore radius (warmbore radius is 140 mm) and a large maximum ﬁeld gradient (14.1 T/m). These features match the requirements of the TOF spectrometer having large angularand momentum acceptances.
Figure 2 schematically shows the conﬁguration of
the detectors in the TOF spectrometer. The TOF
spectrometer is to be placed downstream of the secondary target at the third focal plane (F3) of RIPS.3)
A PPAC and plastic scintillator are mounted, between
the secondary target and the STQ. The PPAC is used
to determine the scattering angle of ejectiles. Its large
sensitive area of 150 × 150 mm2 covers the large angular acceptance of the STQ. The plastic scintillator,
which provides the start timing of TOF, has dimen∗1
∗2
∗3
∗4

176

Department of Physics, Rikkyo University
Department of Physics, University of Tokyo
Department of Physics, Kyoto University
Center for Nuclear Study, University of Tokyo

Fig. 1. The Superconducting Triplet Quadrapole magnet
used for the TOF spectrometer.

sions of 160 mm × 150 mm × 100 µm; a thin material
was chosen to reduce the energy loss in the detector.
Behind the STQ, two PPACs, a plastic scintillator,∆E and E detectors are placed. The two PPACs are located at a distance of 30 cm from each other. The ﬁrst
and second PPACs have dimensions of 150 × 150 mm2
and 100 × 100 mm2 , respectively. They are used todetermine the position and angle of the ions being
focused on the ∆E-E detectors. The plastic scintillator, placed between the two PPACs, provides thestop timing for the TOF. This conﬁguration has theﬂight path length of 3.85 m between the start and stop
scintillators, for which the typical TOF of ions withE ∼30A MeV is ∼50 ns.
The conﬁguration of the ∆E and E counters will be
optimized depending on the stopping range spread ofions. For experiments with A = 60–80 nuclei, 100 µm
Si detectors and two layers of 320 µm Si detectors areused for ∆E and E measurements, respectively. The∆E-layer consists of four sets of 50 × 50 mm2 Si detectors arranged in a two-by-two matrix. The E-layers
consist of round shaped Si detectors with a diameterof 134 mm. Thin ∆E detectors are used because of thesmall stopping range of ions, while relatively thick Elayers are used to cover the wide stopping range spreadof ions. For A∼30 nuclei, a NaI(Tl) scintillator arrayis used as an E counter instead of Si detectors to havethe thick material required by the large stopping rangeof scattering ions.
The distance between the secondary target and thefront face of the STQ is set at 1050 mm as a compromise between the angular acceptance and the spaceFig. 2. Schematic view of the TOF spectrometer.

for the γ-detectors surrounding the target. With thissetup, the distance between the target and the front
face of the vacuum chamber for the start counters is
530 mm; here, users can place their experimental apparatus. This space is suﬃciently wide to place largescale γ-detector arrays such as DALI24) or GRAPE5)
surrounding the secondary target.
The features of the ion optics were investigated,6)
and it was found that the angular acceptance is 100%for angles smaller than two degrees. Taking theH(64 Cr,64 Crγ) experiment as an example, the massof the ejectiles can be separated with 2.7 σ and theoverall acceptance of the TOF spectrometer is 95%,
where the spacial, angular and momentum spreads ofthe beam are taken into account. The other example
is the 4 He(32 Mg,32 Mgγ) experiment, where the mass
separation is 5.4 σ and the overall acceptance is 70%.
With the performance of the TOF spectrometer, sig-

niﬁcant improvement in the quality of experimental
data is expected. All the detectors and the vacuum
chambers are almost ready and the ﬁrst experimentusing the TOF spectrometer is scheduled for the endof 2004.
References
1) K. Kusaka et al.: IEEE Trans. Appl. Supercond. 14,
310 (2004).
2) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
204, 97 (2003) .
3) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
4) S. Takeuchi et al.: RIKEN Accel. Prog. Rep. 36, 148(2003).
5) S. Shimoura et al.: CNS Annu. Rep. 2001, 5.
6) H. Suzuki et al.: RIKEN Accel. Prog. Rep. 38, 178(2005).

177

RIKEN Accel. Prog. Rep. 38 (2005)

Simulation of particle trajectories for the TOF spectrometer
H. Suzuki,∗1 E. Takeshita,∗2 N. Aoi, H. Sakurai,∗1 H. Iwasaki,∗1 T. Kubo, K. Kusaka, K. Yoshida,
T. Motobayashi, and K. Ieki∗2
The TOF spectrometer1) is being developed for use
in in-beam γ spectroscopy at RIPS2) (RIken Projectilefragment Separator) with radioactive beams. Improvement has been made with emphasis on the resolution ofparticle identiﬁcation (PID), which enables us to identify reaction residue with a mass number of around 80.
In the PID, mass number (A) identiﬁcation is generally more diﬃcult than proton number (Z ) identiﬁcation. In the past experiments in RIPS, PID has been
performed mostly by the ∆E -E method with Si detectors. However, the resolution of Si detectors limits themass resolution, and nuclei with A40 are diﬃcult tobe distinguished. The TOF spectrometer employs the
TOF-E method to determine A. To achieve good TOF
resolution, a long ﬂight path (∼4 m) is taken, which isnecessary to attain suﬃcient mass resolution for nuclei with A∼80. To focus the scattered particles on
the small-area detectors for TOF measurement (10 cm
square), Superconducting Triplet Quadrupole magnets(STQ)3) are used. Basic requirements of the TOF
spectrometer are suﬃcient angular acceptance (70% at
2 degrees) and high mass resolution (2 σ separation atA∼80).
To estimate the transmission and mass resolution,
the particle trajectories in STQ were simulated. STQ
have the following characteristic features. Strong magnetic ﬁeld gradients can be generated with a large duct
radius (140 mm). Each magnet in STQ has a shortlength (500 mm or 800 mm) compared with their large
bore radii (170 mm). These features enable it to havelarge angular acceptance for the TOF spectrometer.
On the other hand, these features cause signiﬁcant
fringe ﬁelds. In addition, since STQ generates strong
ﬁelds above the magnetic saturation point, the shapesof the magnetic ﬁeld distributions change with theirstrengths (nonlinearity). To deal with the large fringe
areas properly in the particle trajectory calculation,a code, COSY Inﬁnity4) developed at Michigan State
University, was used. This code can handle any distribution of magnetic ﬁelds given by users. The calculation was performed to the 3rd order.
Measured magnetic ﬁelds were used for the calculation because of the nonlinear feature of STQ. Field
measurements were made at every 20 mm step along
the beam axis at 120 mm in radius. The currents of thecoils were set at 25%, 50%, 75%, 100%, and 120% of
the nominal currents. By interpolating the discretely
measured data, the magnetic ﬁelds were represented ascontinuous functions of currents and positions.
∗1
∗2

178

University of Tokyo
Rikkyo University

The ﬁeld settings were determined to satisfy the focus conditions. Three conditions may be required, because the magnetic ﬁelds for three magnets can be
set independently. In the present calculation, thefollowing conditions were required: being focused in
the x -direction, being focused in the y-direction, andthe same magniﬁcations of the x -direction and the ydirection. To simplify the calculation, rectangular distributions of the magnetic ﬁelds were used in place ofthe realistic ﬁeld distributions. The lengths of the rectangular ﬁelds were taken to be the eﬀective lengths ofthe original realistic ones. The strengths of the rectangular ﬁelds were determined so that the integrals of
the ﬁelds were the same as those of the original realistic ﬁelds. After the ﬁeld settings were determined withrectangular distributions, the transfer matrices were
calculated using the realistic ﬁeld distributions. The
magniﬁcations obtained with rectangular ﬁelds were−1.0 for the x -direction and the y-direction, whereas
those with the realistic ﬁelds were −1.5 and −1.0, respectively. The maximum magnetic rigidity of a particle that can be focused by STQ is 5.0 Tm.
Particle trajectories were calculated using the transfer matrices, as shown in Fig. 1. In this calculation,
position, angle, and kinetic energy spread of the incident particles before the target were taken into account. Energy loss and scattering in the target werealso considered. Gaussian distributions were assumed
for position and angle spread with σ = 1 cm and σ =1 degree, respectively. The kinetic energy spread isset at ±6%. It is seen that the particles pass throughSTQ with wide spatial spread, and some particles hit
the beam duct.
The transmission is calculated as the ratio of thenumber of particles that passed through the STQ to
the total number of particles ejected from the target.

Fig. 1. The particle trajectories in the TOF spectrometerfrom the target to the focal plane in the x -direction (up)and the y-direction (down). The three boxes represent
the quadrupole magnets. The right vertical line represents the focal plane. The two horizontal lines represent
the beam duct.

Fig. 2. The transmission of the TOF spectrometer. The
dashed line shows the transmission for monochromaticparticles from the point source at the center of the target. The solid line shows the transmission based on realistic conditions of the 64 Cr(p,p ) reaction at 30 A MeV.

Figure 2 shows the transmissions as a functions of thescattering angle. The dashed line represents the transmission for monochromatic particles from the point
source at the center of the target. The transmission
is 100% when the scattering angle is up to 2 degrees
in the lab system, and 0% at 6 degrees.
However, in the actual experiments with RI beams,
the position, angle, and kinetic energy of incident particles have ﬁnite spread. The transmission under suchrealistic conditions is calculated and shown by the solidline in Fig. 2. Note that the scattering angle stands forthe deﬂection angle in the target due to the reaction,and thus the outgoing angle is the sum of the incident
angle and the scattering angle.
Considering the angular distributions of the diﬀerential cross section (dσ/dΩ), the overall transmission is
calculated. Taking the 64 Cr(p,p ) reaction at 30 A MeV
as an example, dσ/dΩ has a width of about 0.3 degrees(rms). The total transmission is found to be 95%. In
the case of the 64 Cr(α,α ) reaction at 30 A MeV, thewidths of dσ/dΩ are about 1.2 degrees (rms). In spiteof the large angle spread, a reasonably large transmission of 81% is obtained. The TOF spectrometer provides suﬃcient angular acceptance for the experiments.
Figure 3 shows the image at the focal plane after STQ. In this ﬁgure, the particles which did notreach the focal plane are not drawn. Of the particles
that pass through STQ, 99% hit the detectors (10 cm
square). To have a smaller spot size at the detector,
the magnetic ﬁelds can be adjusted so that the thinnest
point (waist) is at the detector position.

Fig. 3. The image of the particles at the focal plane.
Dashed square in the figure corresponds to the active
size of the detectors at the focal plane after STQ. Two
histograms are projections of the image to x and y axes.
The position spreads are 1.6 cm (rms) in the x -direction
and 0.7 cm (rms) in the y-direction.

The spread of the ﬂight path length shown in Fig. 1
could aﬀect the PID resolution, and worsen the mass
resolution of the PID. In the case of the 64 Cr(p,p ) reaction at 30 A MeV, the ﬂight path spread is calculated
to be 0.12%. Considering this eﬀect, the A (mass number) resolution increases from 0.57% to 0.61%, where
the E resolution of 0.4% (rms) with Si detectors anda TOF resolution of 0.2% (rms) with plastic scintillators are assumed. The separation capability of nuclei
is also decreased from 2.8 σ to 2.5 σ. The worsening of
the mass resolution is not signiﬁcant. If better resolution is required, the spread of the ﬂight path length
can be corrected for by using particle tracking with position detectors. With this correction, the eﬀect of the
spread falls to 0.08% and nuclei of A∼60 are separated
by 2.7 σ.
This spectrometer has satisfactory mass resolution
and angular acceptance. The TOF spectrometer willcontribute a great deal to the study of unstable nuclei
in the medium-mass region.
References
1) N. Aoi et al.: RIKEN Accel. Prog. Rep. 38, 176 (2005).
2) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
3) K. Kusaka et al.: IEEE Trans. Appl. Supercond. 14,
310 (2004).
4) K. Makino and M. Berz: Nucl. Instrum. Methods Phys.
Res. A 427, 338 (1999).

179

RIKEN Accel. Prog. Rep. 38 (2005)

Network and computing environment for RIKEN accelerator
research facility
T. Ichihara, Y. Watanabe, K. Yoshida, and A. Yoshida
The advanced computer network1) started operationin 2002 at the RIKEN Accelerator Research Facility(RARF). Major updates undertaken this year are summarized as follows.
1) Mail Spam Filter
Recently, spam which is unsolicited junk e-mail sent
to large numbers of people to promote products or services, has become a serious problem for all e-mail users.
In some case more than one-hundred spam mails aresent to a person each day. Therefore the daily handlingof spam mails has become a large task for individual
mail users.
In order to resolve this problem, mail frontend
servers for tagging spam mail have been installed. Incoming mails to the RARF mail server (rarfaxp) areﬁrst received by the mail frontend servers (rarfsmtp
or rarfproxy) and spam mails are automatically identiﬁed using SpamAssassin software and tagged in the
mail subject and header ﬁeld.
SpamAssassin2) is a mail ﬁlter which attempts to
identify spam using a variety of mechanisms including
text analysis, Bayesian ﬁltering, DNS blacklists, andcollaborative ﬁltering databases. Using a rule base, itapplies a wide range of heuristic tests to mail headers
and the body of text of the mails to identify spam.
To date, approximately 95–99% of spam mails havebeen correctly identiﬁed as spam in the RARF mailenvironment.
Then, each mail user can delete or separate the spam
mails automatically on the basis of the tagging of the
mail subject or mail header ﬁeld by setting their mailclient software options. As a result, each mail user is
kept almost free from the spam problem by appropriate
use of their mail client software.
2) ftp server (ftp.riken.jp)
An anonymous ftp server (ftp.riken.jp) is managed
and operated at RARF. Recently, many research laboratories in RARF have adopt Linux as their com-puter operating system. In order to conduct the installation and daily management of Linux easily andeﬃciently, major Linux distributions are mirrored at
the ftp servers. Most of the distributions are mirrored daily from the primary master server using thersync protocol. The mirrored Linux distributions3) include fedora core, redhat, debian, suse, scientiﬁc linux(SL), scientiﬁc linux cern (SLC), whitebox, caos (CentOS), tao, slackware, mandrake, mepis, vine, gentoo,
knoppix, ubuntu, plamo and turbolinux distributions.
Also the TeX archives (CTAN), GNU software andmany other useful software packages are mirrored at
the server.
The hardware of the server was replaced with a 2U
rack-mount PC which consists of two sets of a 3.06 GHz
Pentium Xeon CPU and 3.7 GB memory. Two sets of
SATA Raid disks (in total, 3.0 TB) were added to theserver.
Figure 1 shows the current conﬁguration of the
RARF advanced computer network. Between the
RARF internal network and the external Internet, aﬁrewall (PIX 525) has been installed to maintain security.
Figure 2 shows the current conﬁguration of theUNIX cluster servers of RARF.
The RARF Unix cluster consists of eleven nodes ofUNIX servers, four of which are True 64 UNIX (alpha),
ﬁve of which are Linux and two of which are Solaris,
which are connected via the Gigabit or 100 Mbps Ethernet. RARFAXP is the central server for e-mail, text
processing, user home pages and general computing.
RARFAX1-2, RARFLX1-3, and RARFLX10-11 areused mainly for intensive data analysis, middle-scalecalculations and user terminals. RARFSUN is a gateway computer for accessing the internal private network of RARF using SSH. RARFNFS0 is a dedicated
Network File Service (NFS) server which is equippedwith 2.8 TB + 1.7 TB SCSI Raid5 work disks.

Fig. 1. Configuration of the RARF advanced computer network.

180

Most of the RARF users have e-mail addresses ofthe following patterns:
username@rarf.riken.jp or username@riken.jp.
The ﬁrst one represents an e-mail address of the
RARF mail server (RARFAXP) and the second one
represents an e-mail address of the RIKEN mail server(postman).
References
1) T. Ichihara et al.: RIKEN Accel. Prog. Rep. 36, 199(2002).
2) http://spamassassin.apache.org/index.html
3) http://ftp.riken.jp/

Fig. 2. Configuration of the UNIX cluster servers of RARF.

181

RIKEN Accel. Prog. Rep. 38 (2005)

Global analysis of fragmentation functions
S. Kretzer
Hard pQCD reactions produce highly virtual partons that will radiate oﬀ their virtualities, thus evolving into the nonperturbative states that contain observable hadrons. A quantitative understanding of thisprocess, known widely as the fragmentation of partons,
considerably widens the class of reactions that can behandled within a perturbative QCD approach.
A graph such as that shown in Fig. 1 serves as
a popular illustration of QCD factorization.1) It also
displays the role of fragmentation functions Dcπ (z) in
hard scattering phenomenology when there are detected hadrons in the ﬁnal state. The early Field &Feynman2) cascade model for quark fragmentation intomesons is depicted in Fig. 2 and a later ﬁeld-theoretic
deﬁnition in terms of a bilocal operator3) is shownin Fig. 3. At leading twist accuracy, these describe
fragmentation (or decay) functions (now in a narrower
sense of the word) that turn a single parton into asingle-hadron inclusive state, with fractional momentum transfer z from the parton to the hadron. Analogous to parton densities, renormalization induces evolution of the (transposed) DGLAP type:Fig. 3. Bilocal operator (right) introduced by Collins &Soper.

∂Di=
Dj ⊗ Pij .
∂ ln µ j=q,q̄,g(1)

Recent global analyses of fragmentation functions,determined at Next-to-Leading-Order accuracy in
QCD, have been performed.4) The individual ﬁts areconceptually very similar, such that a comparison of
the ﬁts provides a good ﬁrst estimate of the uncertainties in the functions Di (z). As explained above, theuncertainties of these functions are data driven andcan be large. It can indeed be shown5) that the electroweak couplings of up and down quarks at the Z 0pole suggest that only
 ﬂavour-insensitive combinations
such as the singlet q Dq+q̄ are well determined.
We have included semi-inclusive DIS data along withhadroproduction data, mainly from RHIC, in a substantial update of global analyses of fragmentation
functions. Detailed results will be published soon.6)
References

Fig. 1. Factorization in terms of parton densities and fragmentation functions.

Fig. 2. Field & Feynman model of cascade fragmentation.

1) J. C. Collins, D. Soper, and G. Sterman: in Perturbative
Quantum Chromodynamics, edited by A. H. Mueller,(World Scientific, Singapore, 1989), hep-ph/0409313.
2) R. D. Field and R. P. Feynman: Nucl. Phys. B 136, 1(1978).
3) J. C. Collins and D. E. Soper: Nucl. Phys. B 193, 381(1981); Nucl. Phys. B 213, 545 (E) (1983); Nucl. Phys.
B 194, 445 (1982).
4) S. Kretzer: Phys. Rev. D 62, 054001 (2000); B. Kniehl,
G. Kramer, and B. Pötter: Nucl. Phys. B 582, 514(2000); Nucl. Phys. B 597, 337 (2001); L. Bourhis, M.
Fontannaz, J. P. Guillet, and M. Werlen: Eur. Phys. J.
C 19, 89 (2001).
5) S. Kretzer, E. Leader, and E. Christova: Eur. Phys. J.
C 22, 269 (2001).
6) S. Kretzer et al.: in preparation.

183

RIKEN Accel. Prog. Rep. 38 (2005)

Single-inclusive cross sections and spin asymmetries in hadronic
collisions†
W. Vogelsang
A major goal of current experiments using longitudinally polarized protons at RHIC1) is to determine
the nucleon’s polarized gluon density, ∆g. The tool
for accessing ∆g is the spin asymmetry
ALL =

d∆σ
dσ ++ − dσ +−=dσ
dσ ++ + dσ +−(1)

for single-inclusive high-transverse-momentum (p⊥ )reactions such as pp → πX, pp → jet X, and pp → γX.
In Eq. (1), σ ++ (σ +− ) denotes the cross section for the
scattering of two protons of the same helicity (opposite helicities). The cross sections for high-p⊥ reactions factorize into long-distance parts which containthe desired information on the (spin) structure of thenucleon, and short-distance parts which describe thehard interactions of the partons and are amenable to
QCD perturbation theory. To make reliable predictions, it is important to know the next-to-leading order (NLO) QCD corrections to the lowest-order (LO)
Born approximation for the partonic hard-scattering.
This paper gives a brief account of the calculation of(approximate) analytical NLO QCD corrections for thecase of single-inclusive high-pT jet production in longitudinally polarized pp collisions. For this purpose,
we assume that the jet cone is narrow (“small-coneapproximation,” SCA). The actual calculation makes
use of the fact that inclusive hadron and jet production
proceed through the same set of partonic subprocesses.
The NLO corrections for inclusive hadron production
were obtained previously.2) One only needs to properly add and subtract parts with two partons in the jet
cone, where either one or both partons are “observed,”that is, form the jet (see Fig. 1). If all contributions
are appropriately taken into account, collinear singularities in the ﬁnal state cancel, and therefore the dependence on the ﬁnal-state factorization scale, present
for the inclusive-hadron case, cancels as well.
Figure 2 shows the results √for the LO and NLO inclusive jet cross sections at s = 200 GeV, and theFig. 2. Inclusive jet production crosssections in NLO√(solid) and LO (dashed lines) at S = 200 GeV for cone
size R = 0.4. The lower panel shows the K-factors.

Fig. 3. NLO spin asymmetry ALL for four diﬀerent
GRSV3) sets of polarized parton distributions. The“error bars” indicate the expected statistical accuracyδAjet
LL for 40% beam polarization and integrated luminosities of 3 pb−1 .

associated K-factors. In Fig. 3, we show expected spin
asymmetries ALL for jet production at RHIC for various gluon polarizations.
References
Fig. 1. Contributions to the single-inclusive jet cross section from partonic reactions where two essentiallycollinear partons, j and k, form a narrow jet.
†

184

Condensed from the article Phys. Rev. D 70, 034010 (2004)

1) See, e.g., G. Bunce, N. Saito, J. Soﬀer, and W.
Vogelsang: Annu. Rev. Nucl. Part. Sci. 50, 525 (2000).
2) B. Jäger et al.: Phys. Rev. D 67, 054005 (2003).
3) M. Glück et al.: Phys. Rev. D 63, 094005 (2001).

RIKEN Accel. Prog. Rep. 38 (2005)

Spin asymmetry for charged pion production at RHIC
M. Hirai∗ and K. Sudoh
The polarized gluon distribution ∆g(x) is an important clue to the puzzle of the nucleon spin, As a probe,
inclusive π 0 production was measured by the PHENIX
collaboration.1) The cross section for the π 0 production
is sensitive to |∆g(x)|, but is insensitive to its sign because the gg process dominates. Experimental uncertainties are still large. It is unclear whether ∆g(x) has
a positive polarization at this stage.
To study ∆g(x) and its sign, we proposed an investigation of spin asymmetry by using charged pion
production processes.2) Spin asymmetry is deﬁned asfollows:++−

AπLL −π ≡±∆σ π − ∆σ π
σ π+ − σ π−

−

,

(1)

±

where ∆σ π and σ π are the polarized and unpolarized cross sections for charged pion production, respectively. In each pion production, contributions fromgg and qg processes dominate. The gg contribution,
which is proportional to [∆g(x)]2 and so is insensitive
to the sign of ∆g(x), is independent of the charge ofthe measured particle and can be eliminated by using
this asymmetry. The qg contribution, which is proportional to ∆g(x), becomes dominant for this quantity
in the entire pT region. Consequently, the asymmetry
is sensitive to the sign of ∆g(x).
By eliminating the gg contribution, the ambiguity of±
the gluon fragmentation function Dgπ can be removed.
±
The subprocesses accompanying by Dgπ are the gg →gg and q q̄ → gg processes. For instance, the polarizedcross section for the gg → gg process is given by±±π= ∆g(xa ) ⊗ ∆g(xb ) ⊗ Dgπ (z) ⊗ ∆σ̂ gg→gg , (2)∆σgg

where ⊗ denotes the convolution integral and ∆σ̂ isthe partonic cross section. In the diﬀerence between
cross sections for π + and π − , these cross sections can+−cel out each other due to Dgπ = Dgπ . Similarly, theq q̄ → gg process can also be removed. In addition, contributions from gg → q q̄ and q q̄ → q  q̄  processes canalso be eliminated by 
the summation
fragmentation
 of
π+
π−
D
=
D
.
functions for ﬂavors:iiii
The asymmetry can be obtained by the diﬀerence
between the qg → qg process for π + and π − produc±tion. A part of the process accompanied by Dgπ iseliminated, and the asymmetry is given by+−

AπLL −π ∆g ⊗ (∆uv −∆dv ) ⊗ (D1π −D2π ) ⊗ ∆σ̂ qg,g ⊗ (uv −dv ) ⊗ (D1π −D2π ) ⊗ σ̂ qg(3)where ∆fv and fv (x) are the polarized and unpolarized∗Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)

valence quark distributions, respectively. The following relations among the fragmentation functions are
assumed due to the isospin symmetry;

+
+
−
−
Duπ = Ddπ¯ = Dūπ = Ddπ≡ D1π ,
(4)
−
−
+
π
π
π
π+
≡ D2π .
Du = Dd¯ = Dū = Dd
In Eq. (3), (∆uv − ∆dv ) is well determined because
its ﬁrst moment is constrained by the neutron and hyperon beta decay constants. Of course, unpolarized
PDFs are more precisely determined in comparison
with the polarized PDFs. In addition, ambiguity ofthe quark fragmentation functions can be cancelled between the numerator and denominator. Therefore, theasymmetry is obtained by well-known distributions except for the undetermined ∆g(x).
Figure 1 shows the asymmetry given by Eq. (1).
Solid and dotted curves are asymmetries with ∆g(x)and −∆g(x) given by the AAC analysis,3) respectively.
In both cases, we obtain large asymmetries. In particular, the asymmetry with −∆g(x) is negative and theabsolute value is fairly large compared with that of single pion production. In the region 8 < pT < 13 GeV,
the asymmetry is suppressed due to the qq process
which provides a positive contribution and accounts
for 10–15% of the asymmetry. Although q q̄ () → q q̄ ()and qq  → qq  processes also contribute, these contributions are negligible. The main contribution is givenby the qg process; therefore, the behavior of the asymmetry certainly reﬂects the sign of ∆g(x) Although
the asymmetry might be diﬃcult to measure experimentally, it provides a possibility of extracting additional information about ∆g(x), positively its sign,from charged pion production at RHIC.

Fig. 1. Asymmetries for the diﬀerence of charged pion production with AAC ∆g(x) and −∆g(x).

References
1) PHENIX Collaboration, S. S. Adler et al.: Phys. Rev.
Lett. 93, 202002 (2004).
2) M. Hirai and K. Sudoh: Phys. Rev. D 71, 014022(2005).
3) Asymmetry Analysis Collaboration, M. Hirai, S.
Kumano, and N. Saito: Phys. Rev. D 69, 054021 (2004).

185

RIKEN Accel. Prog. Rep. 38 (2005)

Charm-associated W ± boson production at RHIC
K. Sudoh and H. Yokoya∗
The polarized parton distribution functions (PDFs)
play an important role in understanding the spin structure of the nucleon. However, our knowledge of thepolarized sea quark distribution and its ﬂavor structure are still insuﬃcient, since only the combinations∆q + ∆q̄ can be determined in the polarized deep inelastic scattering. We can extract information about∆ū and ∆d¯ distributions from the conventional W ±boson production in the future RHIC experiment.1)
Here, we discuss the possibility of the direct measurement of the polarized strange quark distribution ∆s.
We propose charm-associated W ± boson productionp + p → W ± + c/c̄ + X in polarized-unpolarized proton collisions at RHIC. The partonic subprocesses inleading order are composed of O(αs αw ) 2 → 2 treelevel channels ∆s (∆g) + g(s ) → W − + c, where s
denotes the CKM combination s = |Vcs |2 s + |Vcd |2 d.
Thus, the process is sensitive to ∆s. The relevant processes in W + production are obtained by substituting
antiquarks for quarks. Note that the polarized gluon
distribution ∆g is also undetermined and has a large
uncertainty. The ∆s sensitivity is determined by thebalance between the ∆s · g and ∆g · s processes.
The longitudinal single spin asymmetry is deﬁned
by
AW
L

±

≡

[dσ+ − dσ− ]/dpT dyWd∆σ/dpT dyW=,[dσ+ + dσ− ]/dpT dyW
dσ/dpT dyW(1)where dσ+(−) is the spin-dependent diﬀerential crosssection with positive (negative) helicity for the incident
proton, and pT and yW are the transverse momentum
and the rapidity of W ± boson, respectively.
We show the rapidity distributionof the spin asym√
metry for W − production at s = 500 GeV in Fig. 1,
where pT is integrated over the range: 2 GeV < pT <50 GeV. For numerical calculations, we used theAAC2) and GRV3) parametrizations for the polarized
and unpolarized PDFs, respectively. The energy scale2,
Q2 in PDFs is set as squared W ± boson mass MW
and the charm quark mass is 1.2 GeV. The unpolarized and polarized total cross sections are calculated
as σ ≈ 4.29 pb and ∆σ ≈ 1.11 pb.
As mentioned above, there are two processes, ∆g · sand ∆s ·g, in terms of partonic initial states. In Fig. 1,
the dashed line represents the contribution of the ∆g·s
process to the asymmetry, while the dot-dashed line
shows that of the ∆s · g process. The bold line represents the total asymmetry given by the sum of the twocontributions.
∗186

Department of Physics, Hiroshima University

Fig. 1. Single spin asymmetry for W − production with ex√pected statistical errors at s = 500 GeV and L =−1
800 pb .

We can see that the ∆g·s process dominates in back0), whereas the ∆s ·g dominates inward region (yW0), which implies that it is poforward region (yWtentially possible to separate ∆s from ∆g. Moreover,
the asymmetry in forward region is markedly large.
However, there is a large contribution from the valence d quark distribution in the region, even though
the process associated with the d quark is suppressedby the CKM parameter. W + production might be a
promising way to access the ∆s distribution throughthe process ∆s̄ (∆g) + g(s̄ ) → W + + c̄, since the contribution from the d¯ quark distribution is negligible.
The expected statistical errors in Fig. 1 are estimated using the designed values of the beam polarization (P = 70%), the integrated luminosity (L =800 pb−1 ), and the reconstruction eﬃciency (ε = 10%),
together with the unpolarized total cross sections. The
error bars are large due to the small cross section.
Even if ε is overestimated, the sign of ∆s might bedetermined. These processes will provide a method of
directly measuring the polarized strange quark distribution at RHIC.
References
1) For example, G. Bunce, N. Saito, J. Soﬀer, and W.
Vogelsang: Annu. Rev. Nucl. Part. Sci. 50, 525 (2000),
and references therein.
2) Asymmetry Analysis Collaboration, Y. Goto et al.:Phys. Rev. D 62, 034017 (2000).
3) M. Glück, E. Reya, and A. Vogt: Eur. Phys. J. C 5, 461(1998).

RIKEN Accel. Prog. Rep. 38 (2005)

Hydrodynamic afterburner for the color glass condensate at RHIC†
T. Hirano∗1 and Y. Nara∗2
There has been several important findings in relativistic heavy ion collisions at BNL-RHIC:1) (1) The
relative yield of produced hadrons suggests the chemical equilibrium of the system; (2) The large magnitude of v2 is consistent with ideal hydrodynamic calculations in the low pT region; (3) Suppression in single hadron spectra and disappearance of the away-side
peak in di-hadron spectra at high pT indicate thatsemi-hard jets lose their energies while traversing a
dense (possibly partonic) medium; and (4) The centrality dependence of particle yields is consistent with
the Color Glass Condensate (CGC) picture. However,four distinct models are invoked for analysis of thesedata respectively. Each model has its intrinsic parameters for reproducing the data. Therefore, it is of particular importance to unify these approaches to achieve
a comprehensive understanding of the dynamics in relativistic heavy ion collisions and to make a case forthe discovery of the new state of matter, the quark
gluon plasma. We have already combined three of theabove approaches into a dynamical model.2–4) Alongthe lines of these studies, we describe the initial stages
in heavy ion collisions by employing the CGC picture
and consider the resultant produced gluon distribution
as an initial condition of the sequential hydrodynamic
evolution.
As a first trial, we employ the simplest approach to
the CGC as proposed by Kharzeev, Levin and Nardi(KLN).5,6) The gluon distribution in the CGC collisions at the transverse point xT can be represented by
the kT factorization formula 2
4π 2 Nc
d pT
dNg
=
2
2
d x⊥ dyNc − 1p2T
· d2 kT αs φA (x1 , kT2 ; x⊥ )φB (x2 , (pT − kT )2 ; x⊥ ),magnitude of multiplicity. The energy density distribution at an initial time τ0 , which is to be an initial condition of hydrodynamic simulations, can beobtained from Eqs. (1) and (2) on the basis of theassumption of free streaming for produced gluons in
the longitudinal direction ηs = y, where ηs is a spacetime rapidity. In Fig. 1, the pseudorapidity distributions of charged hadrons in Au + Au collisions at√
sN N = 200 GeV are compared with the PHOBOS
data.7) The impact parameters in the hydrodynamic
simulations are, from top to bottom, 2.4, 4.5, 6.3, 7.9,
and 9.1 fm which are evaluated from the average number of participants at each centrality estimated using
the PHOBOS data.7) We reproduce the rapidity andcentrality dependences of multiplicity very well within
this hybrid approach. Therefore, the KLN kT factorization approach in the CGC provides very good initial conditions for the hydrodynamic simulations. In
summary, we have developed a dynamical model forthe description of the time evolution of highly dense
matter created in heavy ion collisions, on the basis of
the CGC and the hydrodynamic evolution. We haveshown that hydrodynamic simulations using the CGC
initial conditions describe the rapidity and centrality
dependences of charged hadron multiplicity at RHIC.

(1)√
where x1,2 = pT exp(±y)/ s, and y and pT are the rapidity and the transverse momentum of the produced
gluon respectively. For the unintegrated gluon distribution, we parametrize2
 3κCF 2 2Qs 2 , kT ≤ Qs ,2π αs (Qs ) Qs +Λ2
φA (x, kT ; x⊥ ) =2
 3κCF 2 2Qs 2 , kT > Qs ,Fig. 1. Pseudorapidity distribution of charged particle in√
Au+Au collisions at sN N = 200 GeV

2π αs (Qs ) kT +Λ

(2)
where CF = (Nc2 − 1)/(2Nc ), Qs is a saturation scaleand κ is an adjustable parameter which controls the†∗1∗2

Condensed from the article in Nucl. Phys. A 743, 305 (2004)
Department of Physics, Columbia University, USA
Institute für Theoretische Physik, Johann Wolfgang Goethe
Universität, Germany

References
1) Proc. 17th Int. Conf. Ultrarelativistic Nucleus-Nucleus
Collisions, Quark Matter 2004; J. Phys. G 30, S633
(2004).
2) T. Hirano and K. Tsuda: Phys. Rev. C 66, 054905(2002).
3) T. Hirano and Y. Nara: Phys. Rev. C 66, 041901(R)(2002).
4) T. Hirano and Y. Nara: Phys. Rev. C 69, 034908 (2004).
5) D. Kharzeev and M. Nardi: Phys. Lett. B 507, 121(2001).
6) D. Kharzeev and E. Levin: Phys. Lett. B 523, 79(2001).
7) B. B. Back et al.: Phys. Rev. Lett. 91, 052303 (2003).

187

RIKEN Accel. Prog. Rep. 38 (2005)

Global analysis of nuclear data on structure functions F2A
and Drell-Yan processes
M. Hirai,∗1 S. Kumano,∗2 and T.-H. Nagai∗2
Unpolarized parton distribution functions (PDFs) in
the nucleon have been investigated for a long time, andthey are established from small x to large x. However,their nuclear modiﬁcations are not investigated extensively. On the other hand, it is important to know
the modiﬁcations accurately, for example, in heavy-ion
and neutrino reactions for ﬁnding quark-gluon plasma
signatures and neutrino oscillations, respectively.
We proposed optimum PDFs in nuclei by analyzing
nuclear structure function ratios in 2001.1) It was theﬁrst attempt to obtain the nuclear PDFs by a χ2 analysis of high-energy scattering data. In the 2004 version,2) we included Drell-Yan data in the analysis andalso studied uncertainties of the nuclear PDFs. Here,
we discuss the recent results.2)
The nuclear PDFs are expressed by the nucleonicones multiplied by weight functions wi :fiA (x, Q20 ) = wi (x, A) fi (x, Q20 ).

(1)

The initial scale Q20 is taken as Q20 =1 GeV2 . We consider modiﬁcations for valence-quark, antiquark, andgluon distributions: wuv , wdv , wq̄ , and wg . They are
expressed by parameters:
ai + bi x + ci x2 + di x3
1.
wi (x, A) = 1 + 1 − αA(1 − x)βi(2)where Hij is the Hessian matrix, ξ indicates a parameter set, and ξˆ is the optimum one.
The numbers of F2 and Drell-Yan data are 899 and52, respectively, so that the total number is 951. By
the χ2 analysis, we obtain χ2min /d.o.f. = 1.58. Typical results are shown for the calcium nucleus in Fig. 1,
where the weight functions wuv (=wdv ), wq̄ , and wg
are shown at Q2 =1 GeV2 with their uncertainties. The
solid curves are the optimum functions and shaded areas indicate one-σ error ranges.
We ﬁnd that the valence-quark distributions are welldetermined by the F2 data at medium x together withbaryon-number and charge conservations. The antiquark distribution is also well determined at small x;
however, the uncertainties are large in the mediumand large-x regions. The large uncertainties in wg suggest that it should be diﬃcult to ﬁnd the gluon modiﬁcation in the whole x region. Because the nuclear
PDFs are not well investigated, we need further eﬀorts
to reduce the uncertainties.
From the analysis results, we proposed nuclear PDFs
from the deuteron to a heavy nucleus. A code is available on our web site2) for calculating the nuclear PDFs
at given x and Q2 .

In the recent analysis,2) α and βi are ﬁxed at α = 1/3
and βuv =βdv =βq̄ =βg =0.1. The parameters ai , bi , ci ,and di are determined by a χ2 ﬁt to the experimental data on F2 structure-function and Drell-Yan crosssection ratios. The total χ2 is deﬁned by
 (Rjdata − Rjtheo )2
χ2 =
,
(3)
(σjdata )2
j


pA
pA
where Rj indicates a ratio F2A /F2A or σDY
/σDY
, and
data
is an experimental error which is calculated byσj(σjdata )2 = (σjsys )2 + (σjstat )2 . The parametrized distributions are evolved to each experimental Q2 pointby the standard DGLAP evolution equations. Uncertainties of the obtained nuclear PDFs are calculatedby the Hessian method:  ∂f A (x, ξ) [δf A (x)]2 = ∆χ2
∂ξi
ξ=ξ̂
i,j
 A

∂f (x, ξ)
−1
× Hij
,
(4)
∂ξj
ξ=ξ̂


∗1
∗2

188

Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Department of Physics, Saga University

Fig. 1. Modifications of valence, antiquark, and gluon distributions at Q2 =1 GeV2 in the calcium nucleus.2)

References
1) M. Hirai, S. Kumano, and M. Miyama: Phys. Rev. D
64, 034003 (2001).
2) M. Hirai, S. Kumano, and T.-H. Nagai: Phys. Rev. C
70, 044905 (2004); The NPDF code could be obtained
from http://hs.phys.saga-u.ac.jp/nuclp.html.

RIKEN Accel. Prog. Rep. 38 (2005)

Tau polarization in oscillation experiment
M. Aoki,∗1 K. Hagiwara,∗1 K. Mawatari,∗2 and H. Yokoya∗3
The CNGS project1) will start in 2006. The project
includes two long baseline neutrino oscillation experiments, ICARUS and OPERA. These experiments
mainly aim to detect ντ which originates from νµthrough oscillation, propagating from CERN to Gran
Sasso in Italy over a distance of 732 km. ντ appearance
becomes the direct evidence for a three-ﬂavor oscillation scenario. ντ is detected through the τ production
by charged current interaction. The produced τ , however, decays into several particles immediately. Therefore, it is practically important to observe the decay
particle distributions from τ leptons. It is well known
that the τ decay distributions signiﬁcantly depend on
the spin polarization, and therefore it is necessary toobtain information on the spin polarization of τ to simulate the realistic decay particle distributions as theobservables.
We calculated the polarization vector of τ , as wellas the cross section, for the τ production by chargedcurrent neutrino-nucleon scattering2) :ντ (ν̄τ ) + N → τ − (τ + ) + X.

(1)

Quasi-elastic scattering (QE) and ∆-resonance production (RES) are taken into account as identiﬁable
exclusive processes, and we put all other processes
inclusively together into the deeply inelastic scattering (DIS) process. The polarization vector has threedimensional space-like components,
s =P(sin θP cos ϕP , sin θP sin ϕP , cos θP ),2(2)

in the rest frame of τ . P denotes the degree of polarization, which takes 1 for the fully polarized τ and 0
for unpolarized τ . The polarization vector and crosssection of τ production are expressed in terms of thecharged current structure functions and these functions can be calculated separately for each process.
For the QE and RES processes, the form factors of
the transition current are known, and for DIS we attempted the tree level calculation of a parton model.
During this study, we learned that for the τ production
process, the pseudoscalar form factors of the QE andRES processes make a large contribution to both thecross section and polarization, while they make negligibly small contributions for light lepton production.3)
The obtained τ − polarizations are shown in thepτ cos θ − pτ sin θ plane in Fig. 1. The incoming neutrino energies are ﬁxed to 10 GeV. The gray line shows
∗1
∗2
∗3

Theory Group, High Energy Accelerator Research Organization (KEK)
Graduate School of Science and Technology, Kobe University
Department of Physics, Hiroshima University

Fig. 1. Contour map of DIS cross section for τ − production at Eν = 10 GeV. Polarization vectors are shownby arrows, where the arrow length gives the degree ofpolarization, and the direction denotes that of in therest frame of τ with respect to the scattering angle.

the kinematical boundary of the phase space and corresponds to the region of the QE process. The contour
map denotes the DIS cross section, and between theregions of the QE and DIS processes, the RES process
region stands. The vectors in each phase space are theτ − polarization vectors in the rest frame of τ − with thedirection shown with respect to the scattering angle.
We found that both τ − and τ + have large polarization, but that the spin direction varies widely with theenergy and scattering angle.
To simulate the decay particle distribution throughτ , the decay distribution function including the τ polarization is also needed. It has been well investigatedfor most of the major decay modes analytically andalso numerically through experiments.4) We will soon
report on the analysis on the decay particle distribution for CNGS experiments, and its dependence onthe τ polarization. Furthermore, in future high-energy
neutrino oscillation experiments, τ will be produced inlarge quantities and the τ decay into e or µ will becomea signiﬁcant background which needs to be clariﬁed indetail.
References
1) The CNGS Project: see e.g. http://proj-cngs.web.cern.
ch/.
2) K. Hagiwara, K. Mawatari, and H. Yokoya: Nucl. Phys.
B 668, 364 (2003); Erratum-Nucl. Phys. B 701, 405(2004).
3) K. Hagiwara, K. Mawatari, and H. Yokoya: Phys. Lett.
B 591, 113 (2004).
4) S. Jadach, Z. Was, R. Decker, and J. H. Kuehn: Comput. Phys. Commun. 76, 361 (1993).

189

RIKEN Accel. Prog. Rep. 38 (2005)

Density matrix renormalization group in a two-dimensional
λφ4 Hamiltonian lattice model†
T. Sugihara
Hamiltonian diagonalization is a useful method for
nonperturbative analysis of many-body quantum systems. If the Hamiltonian is diagonalized, the system
can be analyzed nonperturbatively at the amplitudelevel using the obtained wave functions.1,2) In addition, one can discuss associated symmetry based on operator algebra.3,4) However, in general quantum ﬁeld
theories, this method does not work without reducing degrees of freedom, because the dimension of the
Hamiltonian increases exponentially as the system size
becomes large. There is a severe limitation on numerical diagonalization of the Hamiltonian. To apply themethod to quantum ﬁeld theories, we need to ﬁnd a
way to remove unimportant degrees of freedom andcreate a small number of optimum basis states.
Wilson’s numerical renormalization group in the
Kondo problem was a successful consideration along
this line.5) To analyze chain models other than the
Kondo Hamiltonian, White proposed the density matrix renormalization group (DMRG) as an extensionof the Wilson’s method.6,7) With DMRG, the calculation accuracy of the target state can be controlled systematically using density matrices. White calculated
the energy spectra and wavefunctions of Heisenberg
chains composed of more than 100 sites using a standard workstation. The DMRG analysis of a 100-site
S = 1/2 chain corresponds to diagonalization of the
Hamiltonian with 2100 ∼ 1030 dimensions. DMRG has
been applied to various one-dimensional models, suchas the Kondo, Hubbard, and t-J chain models, and has
achieved great success. A two-dimensional Hubbard
model has also been studied with DMRG in both realand momentum-space representation.8) DMRG works
well on small two-dimensional lattices and new techniques have been proposed for larger lattices. DMRG
has also been extended to ﬁnite-temperature chain
models using the transfer-matrix technique.9–13) In
particle physics, the massive Schwinger model has beenstudied using DMRG to conﬁrm the well-known Coleman’s picture of half-asymptotic particles at a background ﬁeld θ = π.14) It would be interesting to explore the possibility of applying DMRG to quantum
chromodynamics (QCD) in order to study color conﬁnement and spontaneous chiral symmetry breaking
based on vacuum wavefunctions.
In fermionic lattice models, the number of particles
contained in each site is limited because of the Pauliprinciple. In contrast, in bosonic lattice models, eachsite can in principle contain an inﬁnite number of particles. It is not evident whether Hilbert space can be†

190

Condensed from the article in JHEP 0405, 007 (2004)

described appropriately with a ﬁnite set of basis statesin bosonic models. This point becomes crucial when
DMRG is applied to gauge theories, because gauge particles are bosons. Before working in lattice gauge theories, we need to test DMRG in a simple bosonic modeland recognize how many basis states are necessary foreach site to reproduce accurate results.
In this paper, we apply DMRG to a λφ4 modelwith (1+1) space-time dimensions. We deﬁne a Hamiltonian model on a spatial lattice (only space is discretized) because DMRG is a method based on Hamiltonian formalism. Spontaneous breakdown of discrete Z2 symmetry is studied numerically using vacuum wavefunctions. We obtain the critical coupling(λ/µ2 )c = 59.89 ± 0.01 and the critical exponent
β = 0.1264 ± 0.0073, which are consistent with the16)Monte Carlo15) (λ/µ2 )c = 61.56+0.48−0.24 and the exact
β = 0.125 results, respectively. Our results are basedon extrapolation to the continuum limit with lattice
sizes L = 250, 500, and 1000. The largest lattice size
L = 1000 is approximately twice that of the latest
Monte Carlo lattice size.15) It is shown that the latticesize L = 500 is suﬃciently close to the limit L → ∞.
References
1) K. Harada, T. Sugihara, M. Taniguchi, and M. Yahiro:
Phys. Rev. D 49, 4226 (1994); T. Sugihara, M.
Matsuzaki, and M. Yahiro: Phys. Rev. D 50, 5274
(1994); T. Sugihara: Phys. Rev. D 57, 7373 (1998);
T. Sugihara and M. Taniguchi: Phys. Rev. Lett. 87,
271601 (2001).
2) T. Sugihara: Nucl. Phys. B (Proc. Suppl.) 108, 267(2002).
3) N. Sakai and M. Sakamoto: Nucl. Phys. B 229, 173(1983).
4) P. Fendley, K. Schoutens, and J. de Boer: Phys. Rev.
Lett. 90, 120402 (2003).
5) K. G. Wilson: Rev. Mod. Phys. 47, 773 (1975).
6) S. R. White: Phys. Rev. Lett. 69, 2863 (1992).
7) S. R. White: Phys. Rev. B 48, 10345 (1993).
8) T. Xiang: Phys. Rev. B 53, R10445 (1996); T. Xiang,
J. Lou, and Z. Su: Phys. Rev. B 64, 104414 (2001).
9) R. J. Bursill, T. Xiang, and G. A. Gehring: J. Phys.,
Condens. Matter 8, L583 (1996).
10) X. Wang and T. Xiang: Phys. Rev. B 56, 5061 (1997).
11) T. Xiang: Phys. Rev. B 58, 9142 (1998).
12) N. Shibata: J. Phys. Soc. Jpn. 66, 2221 (1997).
13) I. Peschel, X. Wang, M. Kaulke, and K. Hallberg: Lecture Notes in Physics, Vol.528 (Springer, Berlin, 1999).
14) T. Byrnes, P. Sriganesh, R. J. Bursill, and C. J. Hamer:
Phys. Rev. D 66, 013002 (2002).
15) W. Loinaz and R. S. Willey: Phys. Rev. D 58, 076003(1998).
16) L. Onsager: Phys. Rev. 65, 117 (1944).

RIKEN Accel. Prog. Rep. 38 (2005)

Impact parameter dependence in Balitsky-Kovchegov
equation and Froissart bound
T. Ikeda and L. McLerran∗
The impact parameter dependence of parton distribution functions is an old issue. Recently, it has
been possible to study this issue quantitatively using the Balitsky-Fadin-Kuraev-Lipatov (BFKL) and
Balitsky-Kovchegov (BK) evolution equations. The
BFKL equation resums the leading Feynman diagramsin the form of a linear integrodiﬀerential evolution
equation for gluon density, and its solution grows exponentially with the rapidity Y , which violates unitarity
at large Y values. This is due to the lack of that ﬁnite parton density, or the saturation eﬀect. Thus, the
BFKL equation is replaced by a nonlinear BK equation
including such an eﬀect, which reads∂Y Nxy = Kxyz (Nxz + Nzy − Nxy − Nxz Nzy ),
where



z

≡



z
(x−y)2αS Nc
22π (x−z)2 (z−y)2 ,dz, the BFKL kernel Kxyz≡

and Nxy ≡ NY (x, y) is the scattering amplitude of a quark (q)-antiquark (q̄) dipolewith a hadronic target. Here, αS is the strong coupling constant, Nc is the number of colors, and x (y)is the position of the q (q̄) in the transverse space withrespect to the center of the target; the dipole vector
and impact parameter are deﬁned as r = x − y andb = (x + y)/2, respectively. The nonlinear term in the
r.h.s corresponds to the saturation term responsible forunitarity.
One of the most important issues in saturation
physics, in which the BK equation plays an important role, is how fast the black disc radius RBD in
which NY saturates grows with Y . (We deﬁne RBD
as NY (r, b = RBD ) = 0.5). This is closely related tothe problem of the Froissart bound,1) that is, the total
hadronic cross section is bounded by ∼ ln2 s/s0 withthe energy s ∼ eY . In the saturation regime, the total
2
dipole-nucleus cross section is given by σ ∼ 2πRRB.
If RBD grows at most linearly with Y , the Froissart
bound is saturated.
It has been known that a solution of the BK equation
at high rapidities has a power law tail in the inverse
impact parameter even if the initial distribution has an
exponential falling tail and then violates the Froissart
bound.2) This power law tail at high rapidities originates from the long-range Coulomb force generated
by an incoherent color source. It is, however, naturalfor such a long-range force to be screened in a conﬁning theory such as QCD, and we regularize the BFKL
kernel by introducing the screening mass scale λ3)∗

Kxyz → Kxyz e−λ|x−z| e−λ|z−y| ≡ K̄xyz .
With the modiﬁed kernel K̄ and the initial condition
N0 (r, b) = 1 − exp(−(cr)2 /(1 + cr)e−2µb ), the exponential falling tail in the initial condition is found to
be maintained at high rapidities as long as λ ≥ µ/2.
Practically, this indicates that a good lowest order approximation should be generated if we ignore the impact parameter diﬀusion. Doing that, we obtain an
equation local in the impact parameter∂Y Nr,b = K̄xyz (Nz−r,b + Nz,bz

−Nr,b − Nz−r,b Nz,b ),(1)where Nr,b ≡ NY (r, b).
We solved numerically Eq. (1) with the parameters
αS = 0.2, Nc = 3 and c = 8µ. In Fig. 1, RBD forvarious dipole sizes is plotted as a function of Y . We
found that RBD grows linearly with Y for both λ = 0
and µ, and consequently, the Froissart bound is saturated.3) One might think it is a natural consequenceof the local approximation ignoring the impact parameter diﬀusion. The important point, however, is that
this linear growth of the black disc radius with Y is expected in the full BK equation if its kernel is regulatedby the screening mass of gluons.

Fig. 1. RBD for λ = 0 (solid lines) and µ (dotted lines) is
plotted as a function of Y at r = 0.1, 0.01 and 0.001.

References
1) M. Forissart: Phys. Rev. 123, 1053 (1961).
2) K. Golec-Biernat and A. M. Stasto: Nucl. Phys. B 668,
345 (2003).
3) T. Ikeda and L. McLerran: hep-ph/0410345.

Department of Physics, Brookhaven National Laboratory,
USA

191

RIKEN Accel. Prog. Rep. 38 (2005)

Soft modes at the QCD critical point in the chiral quark model
M. Ohtani and H. Fujii∗
Theoretical studies of QCD thermodynamics havepredicted rich phase structure in the plane of temperature T and the chemical potential for the baryon number. Experiments of high-energy heavy-ion collisions
are now ongoing and planned in order to explore these
new states of matter experimentally. Based on the lattice QCD as well as the eﬀective model calculations,
it is suggested that there exists a critical end point of
the ﬁrst-order transition line, which we call Z2 CP toemphasize the symmetry aspect. Since it is a singular point, we expect to obtain clearer information of it
from experiments.
The critical behavior associated with the Z2 CP has
been discussed in order to locate its position experimentally. We emphasize that at the Z2 CP, the susceptibilities of the baryon number and energy densities
as well as that of the scalar density diverge with thesame strength (critical exponent), unlike at the critical point in the chiral limit. This is demonstrated bystudying the Ginzburg-Landau (GL) eﬀective potential.1) In the chiral limit, the order parameter is identiﬁed as the scalar density, and no linear coupling of
the scalar density with the baryon number and energy
densities can be allowed because of the chiral symmetry. In contrast, near the Z2 CP, the ﬂuctuations ofthese three densities can be mixed and the proper ordering density becomes a particular linear combinationof them. The susceptibilities of these densities containthe singular component and show the same divergenceat the Z2 CP.
At a critical point, a soft mode emerges which has
a time scale much slower than those of other modes.
Here we discuss the soft mode associated with Z2 CP,
which causes the critical divergences.1,2) It is known
that susceptibility χ, obtained in a q-limit of the response function χ(ω, q), is related to a mode spectrumas ∞Pρ(ω, q)(1)dωχ = lim χ(0, q) = lim
q→0q→0 2π −∞ωwith the spectral function ρ(ω, q) = 2Imχ(ω, q). The
critical divergence is caused by the unintegrable singularity in the integrand at ω = 0 as q → 0.
We show the spectral density ρ(ω, q) of the scalar
channel at Z2 CP in the chiral quark model in Fig. 1.
The quark-pair creation and annihilation contributeto the timelike spectrum while the spacelike spectrum
stems from the Landau-damping-type process possible
only in a medium. The gap seen between these two
spectra is due to the nonzero quark mass. The divergence at the Z2 CP is caused by the enhancement of the∗192

Institute of Physics, University of Tokyo

Fig. 1. Spectral function of the scalar channel at Z2 CP.

spacelike spectrum at the origin (Fig. 1). Corresponding to the critical enhancement near ω ∼ 0, we founda pole of the response function on the pure imaginary
axis of the complex ω plane.
The baryon number and energy densities are conserved quantities, and their ﬂuctuations are hydrodynamic slow modes of the system. It is known that theﬂuctuation of a conserved quantity has the spectrum∝ δ(ω) as q → 0, which means that it cannot oscillate
at q = 0. The divergence of their susceptibility can becaused only by the unlimited growth of the strength of
this δ(ω) spectrum as the critical point is approached.
In fact, within the chiral quark model, we obtained thecharacteristic enhancement near ω ∼ 0 in the spectral
density of the vector channel, which is related to thebaryon number density. This leads us to an important conclusion: the critical slow mode at the Z2 CP,
which generates the divergences in the baryon number
and energy susceptibilities, must have a hydrodynamic
character. The critical mode spectrum seen in Fig. 1
appropriately possesses this property.
At Z2 CP, the quark number and entropy susceptibilities are divergent, wherein only the hydrodynamic
spectrum contributes. This means that extra softness
or critical slowing of a hydrodynamic mode near Z2 CP
is required to give these divergences.
Phenomenological consequences of this observation
should be elaborated more carefully, taking into account factors such as the ﬁnite size eﬀect in spacetime and approximate chiral symmetry. The spectral
function in the chiral quark model used here does notsatisfy the spectral condition, which also should be improved.
References
1) H. Fujii and M. Ohtani: Phys. Rev. D 70, 014016(2004).
2) H. Fujii: Phys. Rev. D 67, 094018 (2003).

RIKEN Accel. Prog. Rep. 38 (2005)

Melting pattern of diquark condensates in quark matter†
K. Iida, T. Matsuura,∗ M. Tachibana, and T. Hatsuda∗
Thermal color superconducting phase transitions inhigh density three-ﬂavor (uds) quark matter are investigated in the Ginzburg-Landau (GL) approach. Effects of nonzero strange quark mass (ms ), electric andcolor charge neutrality, and direct instantons are considered. Weak coupling calculations show that an interplay between the mass and electric neutrality eﬀects
near the critical temperature gives rise to three successive second-order phase transitions as the temperature
increases: a modiﬁed color-ﬂavor locked (mCFL) phase(ud, ds, and us pairings) → a d-quark superconducting(dSC) phase (ud and ds pairings) → an isoscalar pairing phase (ud pairing) → a normal phase (no pairing).
The dSC phase is novel in the sense that while all eightgluons are Meissner screened as in the mCFL phase,
three out of nine quark quasiparticles are always gapless. The present anaysis is expected to give a plausible
idea of what may occur in the strong coupling regimeof physical interest continuously connected to the weakcoupling regime.
We adopt the GL approach near the transition temperatures, which was previously used to study themassless three-ﬂavor case.1) In a realistic situation, theGL potential acquires the following corrections. Firstof all, nonzero ms aﬀects the GL potential through reduction in the Fermi momentum of s quarks in sucha way as to lower the critical temperature of the pairing involving s quarks. Secondly, the chemical potential shift, δµi = −qi µe (i = u, d, s; µe : the electron
chemical potential), for electrically neutral and betaequilibrated system with a gas of electrons aﬀects the
GL potential so as to lower the critical temperatureof the ij pairing with a smaller value of (δµi + δµj )/2.
Thirdly, the instanton contribution gives an mi dependence to the GL potential through the eﬀective four
fermion interaction. In the limit of weak coupling inwhich the diquark pairing arises in the most attractive
color-ﬂavor antisymmetric channel with J P = 0+ ,2)
the ﬁrst and second corrections are of the same order,
characterized by a small dimensionless parameter, 2 2
ms
3π
√
σ=
,
(1)
8 2 gµ2
where g is the color coupling constant, and µ is thequark chemical potential. In this limit the third correction is dominated over by the ﬁrst and second corrections. We remark that the color neutrality makes
negligible correction to the GL potential near the transition temperatures as shown in Ref. 1.
†∗

Figure 1 depicts the melting pattern of diquark condensates in weak coupling. We may understand thebifurcation of the transition temperatures as follows.
In the massless case (a), Tc is degenerate between the
CFL and 2SC phases, the chemical potential is common to all three ﬂavors and colors, and the CFL phaseis more favorable than the 2SC phase below Tc . As
one goes from (a) to (b), the density of states of thes quarks at the Fermi surface is reduced. Then, the
CFL phase becomes anisotropic in ﬂavor space andhas the critical temperature lowered. Eventually, the2SC phase is allowed to appear at temperatures between Tcs and Tc . As one goes from (b) to (c), theaverage chemical potential of ds (ud and us) quarks
increases (decreases) since µe  m2s /4µ. Accordingly,
the transition temperatures further change from Tc to
TcIII and from Tcs to TcI and TcII . We remark that wehave analyzed the melting pattern in the mean-ﬁeldlevel. Eﬀects of thermally ﬂuctuating color magnetic
ﬁelds3) could change the melting pattern.

Fig. 1. Transition temperatures of the three-flavor color
superconductor in weak coupling: (a) all quarks aremassless; (b) nonzero ms in the quark propagator isconsidered; (c) electric charge neutrality is further imposed. The numbers attached to the arrows are in unitsof σTc .

References
1) K. Iida and G. Baym: Phys. Rev. D 63, 074018 (2001);
Phys. Rev. D 66, 059903 (E) (2002).
2) W. E. Brown, J. T. Liu, and H. C. Ren: Phys. Rev. D
62, 054016 (2000).
3) T. Matsuura, K. Iida, T. Hatsuda, and G. Baym: Phys.
Rev. D 69, 074012 (2004).

Condensed from the article in Phys. Rev. Lett. 93, 132001(2004)
Department of Physics, University of Tokyo

193

RIKEN Accel. Prog. Rep. 38 (2005)

Linking the chiral and deconfinement phase transitions
Y. Hatta and K. Fukushima∗
Lattice simulations of finite temperature quantum
chromodynamics (QCD) have shown that the chiralphase transition in the chiral limit and the deconfinement phase transition in the quenched limit arecontinuously connected. In this report we propose anovel scenario which naturally explains this longstanding puzzle.
The deconfinement phase transition has a definite
meaning only at an infinite quark mass. In SU(3)pure gluodynamics the transition is known to be of
the first order. The expectation value of the Polyakov
loop serves as an order parameter and jumps at thedeconfinement transition temperature. The first-orderphase transition persists at a finite but very large quark
mass (solid curve in Fig. 1) and eventually terminates
at a second-order phase transition point D where thePolyakov loop becomes massless.
In contrast, chiral symmetry is a true symmetry only
at a zero quark mass. The order parameter of the chiralphase transition, the sigma field σ, becomes masslessat the end point of the first-order transition C.
A priori, there seems to be no relationship between
the chiral and deconfinement phase transitions. However, lattice simulations have revealed a very interesting interplay between the two. Figure 1 is the mostcommonly accepted phase diagram for QCD in thetemperature-quark mass plane. T is the temperatureand m is the quark mass. The solid (dotted) curve
represents the first-order (crossover) phase transition.
This figure shows that, for all values of the quark mass,
there is a single (crossover) phase transition whichsmoothly connects the chiral phase transition in thechiral limit and the deconfinement phase transition in
the quenched theory.

In order to understand this lattice result, first, we
propose an alternative characterization of the deconfinement phase transition. We point out that, in thepresence of dynamical quarks, the deconfinement phasetransition can equivalently be characterized in terms ofthe glueball field G. Specifically, we have shown1) thatthe screening mass of the 0+ electric glueball vanishes
at point D.
Next, we observe that the glueball field G must mix
with the sigma field σ so that the correct massless field
at D is a linear combination of the two:φ = G cos θ + σ sin θ,

sin θ ≈ 0.

(1)

The orthogonal linear combination with large sigma
field content,φ = −G sin θ + σ cos θ,(2)is massive. Now the key question concerns the behavior of the mixing angle θ as the quark mass varies.
If the mixing angle remains small at small values ofquark mass, the φ field, which is massive at D, would
become massless at C because the critical field at C isdominantly sigma-like. However, if this were the case,the coincidence of the two critical temperatures for all
values of the quark mass would be a pure accident.
Figure 1 is most naturally explained by postulatingthat the critical field at C is again the φ field. Namely,
the two second-order phase transitions at C and D are
driven by the same field. This is possible only if themixing angle changes from θ ≈ 0 to ≈ π/2. Such acontinuous variation of the mixing angle is typical of alevel repulsion in quantum mechanics. Thus, we havearrived at a novel scenario of the finite temperature
QCD phase transition: Due to a level repulsion between the φ and the φ fields, the φ field continues tobe the lightest screening state for all values of quark
mass. Simultaneous divergences and peaks in various
susceptibilities are simply caused by the dropping ofthe φ field screening mass.
Moreover, we speculate that this scenario is realized
at all temperatures. The level repulsion between thescalar glueball and the sigma meson already occurs atzero temperature, as one can easily convince oneself byconsidering the scalar meson and glueball mass spectrum at zero temperature. Therefore, our scenario canbe naturally embedded in the entire phase diagram
shown in Fig. 1.
Reference

Fig. 1. The phase diagram in the (T, m) plane.
∗

194

Center for Theoretical Physics, Massachusetts Institute ofTechnology, USA

1) Y. Hatta and K. Fukushima: Phys. Rev. D 69, 097502(2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Cut-oﬀ eﬀects in meson spectral functions
T. Blum∗1 and P. Petreczky∗2
Temporal meson correlation functions in Euclidean
time can be related to meson spectral functions by analytic continuation. Furthermore using the Maximum
Entropy Method one can extract the spectral functions
from meson correlators calculated on a ﬁnite lattice.1)
The method was applied at zero1,2) as well as non-zerotemperature.3–6) In such an analysis one usually uses
all time slices in the correlation function not just thelong distance part. Therefore one is sensitive to shortdistance physics which may be aﬀected by lattice artifacts. The lattice distortion of the correlators at shortdistances translates into lattice artifacts in the spectral
functions for large energies. So far only Wilson gauge
action and Wilson (clover) fermion action have beenused to study meson spectral functions. The lattice
artifacts seen in numerical simulations for this combination of actions turns out to be quite diﬀerent fromwhat is expected in the free theory. Therefore we study
cutoﬀ eﬀects of meson spectral functions using diﬀerent gauge and fermion actions.
We consider the temporal correlators of local meson operators in the pseudo-scalar and vector channels. We use quenched domain wall fermion correlators on DBW2 gauge conﬁgurations from the RBC
collaboration. Furthermore, we calculate tree-level
clover fermion correlators on quenched 1-loop tadpoleimproved Symanzik lattices and on partially-quenched
2+1 ﬂavor Asqtad fermion lattices from the MILC collaboration. To extract the spectral function we use
the Maximum Entropy Method. We also parameterize the spectral
functions as a sum of delta functions
σ(ω) = i Fi δ(ω 2 −m2i ) and determine the parameters
Fi and mi using constrained curve ﬁtting techniques7)
which allows for better systematic control of the results.
We start the discussion of our numerical resultswith the case of domain wall fermions. Here we performed calculations at three diﬀerent lattice spacings,
a−1 = 1.3, 2.0, 3.0 GeV and valance quark mass aroundthe strange quark mass. For the coarsest lattice we see
a two peak structure in the spectral functions with thesecond peak located around 2 GeV. The positions of
the peaks are reasonably reproduced using a two exponential ﬁt. For ﬁner lattices we see a three peak

∗1∗2

structure. We ﬁnd that the position of the ﬁrst peakis independent of the lattice spacing, thus it is clearlycorrespond to a physical states (the η and φ mesons).
The position of the second and third peaks on the otheris shifted approximately as 1/a as the lattice spacing
has been changed. Which means that these peaks arelattice artifacts. Similar results were found for the Wilson action.1,2) In Ref. 2 they were interpreted as boundstates of Wilson doublers. For DWF, however, such aninterpretation is more diﬃcult to apply. We have also
performed a constrained ﬁt with three exponentials.
The ground state mass was obtained from a simple unconstrained ﬁt which was then used as a prior for theconstrained ﬁt. We have found a reasonable agreement
between the MEM and constrained curve ﬁts.
One may wonder whether the second and third peaks
are artifacts of quenching. Absent dynamical quarks,
all hadrons are absolutely stable (i.e. have zero width)no matter how large their mass is. The situation is
diﬀerent in full QCD where mesons can decay andthe lattice artifacts may be absent. To check this
we performed calculations in quenched and partiallyquenched QCD using the clover action. More precisely
we used gauge conﬁgurations with Symanzik action
generated by the MILC collaboration as well the dynamical 2+1 Asqtad conﬁgurations. In both cases thelattice spacing was a ≈ 0.09 f m. We use the tree-levelvalue for the clover coeﬃcient, csw = 1, and κ = 0.14
which corresponds to mP S /mV = 0.68. We have foundthat the spectral functions for quenched and partiallyquenched QCD are very similar, indicating that forquark masses around the strange quark mass eﬀects
due to quenching are quite small.
References
1) Y. Nakahara et al.: Phys. Rev. D 60, 091503 (1999); M.
Asakawa et al., Prog. Part. Nucl. Phys. 46, 459 (2001).
2) Yamazaki, et al.: Phys. Rev. D 65, 014501 (2002).
3) F. Karsch, et al.: Phys. Lett. B 530, 147 (2002).
4) T. Umeda et al.: hep-lat/0211003.
5) M. Asakawa and T. Hatsuda: Phys. Rev. Lett. 92,
012001 (2004).
6) S. Datta, et al.: Phys. Rev. D 69, 094507 (2004).
7) G. P. Lepage, et al.: Nucl. Phys. B (Proc. Suppl.) 106,
12 (2002).

Physics Department, University of Conneticuit, USA
Physics Department, Brookhaven National Laboratory,
USA

195

RIKEN Accel. Prog. Rep. 38 (2005)

Matrix models and lattice simulations for QCD at nonzero density
T. Wettig∗
QCD at nonzero density continues to be an important ﬁeld of current research, in particular because of
its relevance to RHIC physics. Nonperturbative studies of the theory by means of unquenched lattice simulations are extremely diﬃcult because of the sign problem. Theoretical arguments1) show that this sign problem can probably not be overcome by standard methods. It is therefore useful to study the theory using
other approaches, e.g. low-energy eﬀective theories or
random matrix theory (RMT).
In last year’s edition of RIKEN Accel. Prog. Rep.,
G. Akemann and I reported on quenched lattice simulations of QCD at nonzero chemical potential to test
the predictions of a random eigenvalue model for the
QCD Dirac operator.2) Akemann’s model was formulated and solved in Ref. 3, and the details of our work
can be found in Ref. 4. We observed nice agreement between the theoretical predictions and the lattice data.
However, Akemann’s model is diﬀerent from an earlier random matrix model for QCD at nonzero density
by Stephanov5) . The virtue of Akemann’s model wasthat it could be solved analytically for the universal
spectral correlation functions of the QCD Dirac operator for which results were not available in Stephanov’s
model. However, after completion of our work, Splittorﬀ and Verbaarschot6) as well as Osborn7) independently derived such results for Stephanov’s model.
Their results agree with each other but diﬀer fromthose obtained by Akemann, although the numericaldiﬀerence is very small.
Since Stephanov’s model can be derived from thelow-energy eﬀective partition function of QCD atnonzero density, it is believed to provide a correct description of the full theory at suﬃciently low energies.
It is therefore important to show on the basis of lattice data that Stephanov’s model, and not Akemann’s,
is the correct one. This is not completely trivial because the numerical diﬀerence between the results ofthe two models is so small. Furthermore, since theDirac spectrum spreads into the complex plane, very
high statistics (on the order of 20,000 conﬁgurations)is needed to obtain reasonably small error bars.
To be able to resolve the diﬀerence between the twomodels, we concentrate on the spectral density of the
Dirac operator for small eigenvalues on the scale ofthe mean level spacing and consider a domain (sometimes called strong nonhermiticity) in which the results depend only on the absolute value of the Diraceigenvalue. This allows us to obtain higher statistics
by integrating over the phase of the eigenvalues. The∗

196

Institute for Theoretical Physics, University of Regensburg,
Germany

corresponding result for Akemann’s model is3)√
ρA (z) = 2πu |z| exp(−u|z|2 )Iν (u|z|2 ) ,(1)

whereas for Stephanov’s model one obtains8)
ρS (z) = 2u|z|2 Kν (u|z|2 )Iν (u|z|2 ) .

(2)In both cases the scale is set by a parameter u, and thedensity is normalized such that the asymptotic value isunity. I and K denote Bessel functions, and the index
ν is zero in our case4) .
In Fig. 1 we show ﬁts of the same lattice data to these
two equations. While both analytical results are inqualitative agreement with the data, Eq. (2) provides
the better ﬁt, which is apparent both by inspection
and by the χ2 values of the ﬁts. We therefore conclude
that the results derived in Refs. 6, 7 for Stephanov’s
model describe lattice data for the QCD Dirac operator
at nonzero chemical potential at a quantitative level.
Akemann’s model, while providing results that are numerically very close to those obtained in Stephanov’s
model, appears to be ruled out by the lattice data.

Fig. 1. Density of small Dirac eigenvalues as a functionof the absolute value of the eigenvalue. The solid
curves represent Eqs. (1) and (2), respectively, withu = 1. The histograms represent (identical) latticedata rescaled by the respective ﬁt parameter u. The
lattice simulations (20,000 conﬁgurations) were done at
β = 5.0 and chemical potential µ = 0.2.

References
1) M. Troyer and U.-J. Wiese: cond-mat/0408370.
2) G. Akemann and T. Wettig: RIKEN Accel. Prog. Rep.
37, 211 (2004).
3) G. Akemann: Phys. Rev. Lett. 89, 072002 (2002); J.
Phys. A 36, 3363 (2003).
4) G. Akemann and T. Wettig: Phys. Rev. Lett. 92,
102002 (2004).
5) M. A. Stephanov: Phys. Rev. Lett. 76, 4472 (1996).
6) K. Splittorﬀ and J. J. M. Verbaarschot: Nucl. Phys. B
683, 467 (2004).
7) J. C. Osborn: hep-th/0403131.
8) J. J. M. Verbaarschot: hep-th/0410211, Eq. (481).

RIKEN Accel. Prog. Rep. 38 (2005)

Two-particle wave function with four-dimension Ising model
T. Yamazaki
The calculation of the scattering phase shift of
hadrons is important in understanding a strong interaction. The phase shift in the I = 2 ππ scatteringsystem1) was evaluated in lattice QCD with the ﬁnite volume method.2,3) A two-particle wave function
plays an important role in the scattering system, because the phase shift can be extracted from the wave
function. Recently, Ishizuka and Yamazaki and Aoki
et al. have numerically studied the wave function in the
I = 2 ππ scattering system.4) They extracted the scattering length and scattering eﬀective potential fromthe wave function only for the two-pion ground state.
Here, we attempt to calculate the wave functions of theﬁrst excited and unstable states in a four-dimensional
simple Ising model.5) We also attempt to evaluate thephase shift from these wave functions.
The wave function φ(r) satisﬁes the Helmholtz equation2,3) (∇2 + p2 )φ(r) = 0 in r > R, where r is the relative coordinate of two particles and p is the relative
momentum. R is the eﬀective range where the eﬀective scattering potential becomes suﬃciently small inthe exterior region of R. The general solution of theHelmholtz equation in a ﬁnite volume under periodic
boundary conditions is given by (1)G(r) = (1/L3 ) k eik·r /(k2 − p2 ) (r = 0)
where k = (2π/L) · n with n being an integer vector.
We can extract p2 by ﬁtting φ(r) in r > R with G(r),and then evaluate the phase shift with the ﬁnite volume
method.
Our employed model is a simple model where thecoupling of a low-mass ﬁeld (π) to a high-mass ﬁeld(σ) with three-point coupling is considered. We perform the simulation on the lattice size L3 × T =203 × 64 with a large number of conﬁgurations,
405×103 . We calculate three- and four-point functions, Fi (r, t) = 0|W(r)[Oi (t) − Oi (t + 1)]|0 and
Cij (t) = 0|Oi (0)[Oj (t)−Oj (t+1)]|0 for i, j = 0, 1 andσ, in order to obtain the wave functions. The operators
Oi (t) represent the ππ operator with p = 0, 2π/L andthe σ operator (i = σ). The wave function operator
W(r) is deﬁned by W(r) = (1/L3 ) X π(r + X)π(X).
The subtraction [Oi (t) − Oi (t + 1)] is performed toeliminate the vacuum contribution.
The wave function is deﬁned by φα (r) = 0|W(r)|α
for the α = 0, 1 and σ states. Using φα (r) andFi (r, t) =overlapVαi = α|Oi |0 , one can calculate


t
φ
(
r
)∆
(t)V
and
C
(t)
=
V
∆
α
α
αi
ij
α
α iα α (t)Vαj ,where ∆α (t) = (1 − e−Eα ) e−Eα t + (1 − eEα ) e−Eα (T −t) .
The overlaps and energies are extracted by the diagonalization method.6) The wave function φα (r) is evaluated except the normalization
through the appropriate−1. In this analysis, we
projection φα (r) = i Fi (r, t)Viα

assume that contributions for higher energy states are
negligible in the correlation functions.
The ﬁtting of φα (r) is carried out by assuming theeﬀective ranges R = 7, 9 and 8 for the α = 0, 1 and σstates. Two ﬁtting parameters correspond to an overall
constant of Eq. (1) and the relative momentum p2 .
Figure 1 shows the ﬁtting result Gα (r) for each state.
The results for all states are consistent with φα (r).
This ﬁgure illustrates that the wave function in r > R,even for the σ state, can be described by the generalsolution of the Helmholtz equation.
We determine the relative momentum p2 by two
methods in order to calculate the phase shift. The
relative momentum p2 can be evaluated from the wave
2
function.
 Alternatively, p can be given by the relation22Eα = 2 m + p . Table 1 shows the results obtainedby both methods for comparison. It is clear that theresults obtained by both methods are reasonably consistent with each other. The results obtained by theformer method for the ground and ﬁrst excited states
have smaller errors than those of the latter method.
As for the σ state, however, the former method yields
a relatively larger error. The reason for this opposite
trend is not well understood at present. To clarify thisfeature, a more detailed study is required particularly
for the calculation of the wave function of the σ state.

Fig. 1. Fitting result of wave functions.
Table 1. Scattering phase shift (degrees) obtained fromwave function and energy.
state
0
1
σ
wave function −1.48(31) −15.0(1.1) 39.8(4.9)
energy−1.96(63) −14.0(2.1) 47.8(1.2)

References
1) CP-PACS Collaboration, S. Aoki et al.: Phys. Rev.
D 67, 014502 (2003); CP-PACS Collaboration, T.
Yamazaki et al.: Phys. Rev. D 70, 074513 (2004); C.
Kim: Nucl. Phys. B (Proc. Suppl.) 129, 197 (2004).
2) M. Lüscher: Commun. Math. Phys. 105, 153 (1986).
3) M. Lüscher: Nucl. Phys. B 354, 531 (1991).
4) N. Ishizuka and T. Yamazaki: Nucl. Phys. B (Proc.
Suppl.) 129, 233 (2004); CP-PACS Collaboration, S.
Aoki et al.: hep-lat/0409063.
5) T. Yamazaki: hep-lat/0409099.
6) M. Lüscher and U. Wolﬀ: Nucl. Phys. B 339, 222(1990).

197

RIKEN Accel. Prog. Rep. 38 (2005)

Penta-quark baryon in anisotropic lattice QCD
N. Ishii,∗1 T. Doi, H. Iida,∗1 M. Oka,∗1 F. Okiharu,∗2 and H. Suganuma∗1
The LEPS group at SPring-81) has discovered a narrow resonance Θ+ , with a mass of 1.54(1) GeV and awidth smaller than 25 MeV. This resonance has baryon
number +1, charge +1 and strangeness +1. Hence,
its simplest conﬁguration is uudds̄, i.e., a manifestly
exotic penta-quark (5Q) state. After this discovery,
many experiments have conﬁrmed the LEPS results
where neither spin or parity was determined. On theother hand, a few experiments have reported null results. Therefore, further studies from both experimental and theoretical viewpoints are required concerning its existence and quantum number, particularly,
its parity.
In this report, we study the 5Q baryon Θ+ using lattice QCD, which is a direct nonperturbative calculation from QCD. Although there have been several lattice QCD studies of 5Q,2–6) they have not yet reacheda consensus, i.e., Refs. 2, 3, and 6 claimed the existenceof 5Q resonance in negative parity, whereas Ref. 4
claimed its existence in positive parity. Ref. 5 reported
observation of no evidence for narrow resonances. Under these circumstances, we perform high-precision
analysis for the 5Q state with the quenched anisotropic
lattice QCD. We generate 504 gauge conﬁgurations
using the standard Wilson gauge action at β = 5.75
3(a−1
s = 1.1 GeV) on the 12 ×96 lattice with the renormalized anisotropy as /at = 4. The O(a)-improved
Wilson quark (clover) action is employed with hopping
parameters as κ = 0.1210–0.1240, where κs = 0.1240
ﬁxed for an s quark, and κ = 0.1210–0.1240 for u and dquarks. This corresponds to mπ /mρ = 0.81–0.65. We
consider a non-NK-type operator for 
5Q withJ = 1/2,

 T
 T

I = 0 as O ≡ abc ade bf g ud Cγ5 de uf Cdg C s̄Tc ,as an attempt to reduce the overlap with the NK scattering state. This is a crucial diﬀerence from Ref. 5, in
which a simple NK operator was adopted. To enhance
the low-lying spectra, we adopt a smeared source withthe gaussian size ρ  0.4 fm. For details, see Ref. 7.
We ﬁrst study the eﬀective mass in both parity
channels, where parity projection is performed withP± ≡ (1 ± γ4 )/2. For both parity channels, we ﬁndplateaus and perform the single-exponential ﬁt. At
each κ, we observe that the positive-parity state ismuch more massive than the negative-parity state. After the chiral extrapolation, the positive-parity state isdetermined at m5Q  2.25 GeV, which is too massive
to be identiﬁed with the experimentally observed Θ+ .
The negative-parity state is found at m5Q  1.75 GeV,
which is rather close to the empirical value.
In order to identify whether the negative-parity state
∗1
∗2

198

Department of Physics, Tokyo Institute of Technology
Department of Physics, Nihon University

is a compact 5Q state or just an NK scattering state,
we propose the hybrid boundary condition (HBC)
method. In this method, we impose the spatial BC
on quark ﬁelds in a ﬂavor-dependent manner, i.e., antiperiodic BC on u and d quarks, and the periodic BC
on the s quark. Under HBC, hadrons are subject totheir own spatial BC, i.e., N(uud, udd) and K(us̄, ds̄)are subject to the antiperiodic BC, while Θ+ (uudds̄) is
subject to the periodic BC. Recall that, in a box of size
L, the spatial momenta are quantized as pi = 2ni π/Lfor periodic BC and (2ni + 1)π/L for antiperiodic BC.
Therefore,
threshold energy is raisedas s-wave NK √
22 , |
+ m2K + pminpmin | = 3π/L.
Eth  m2N + pmin
In contrast, Θ+ can have zero spatial momentum andthe energy is expected to be unaﬀected.
In Fig. 1, we show the comparison of the results ofstandard BC and HBC for each κ. We see that, for all
κ, the plateaus are raised a consistent amount with theshift in NK threshold energy. Therefore, we conclude
that the observed states in the negative-parity channel are NK scattering states and there are no relevant
signals for the compact 5Q resonance.

Fig. 1. Comparison of the results of standard BC and HBCfor each κ. Dots denote the best-fit mass and the solidlines the corresponding NK threshold energies.

References
1) LEPS Collaboration, T. Nakano et al.: Phys. Rev. Lett.
91, 012002 (2003).
2) F. Csikor, Z. Fodor, S. D. Katz, and T. G. Kovacs:
JHEP 0311, 070 (2003).
3) S. Sasaki: hep-lat/0310014.
4) T. W. Chiu and T. H. Hsieh: hep-ph/0403020; hepph/0404007.
5) N. Mathur, F. X. Lee, A. Alexandru, C. Bennhold, Y.
Chen, S. J. Dong, T. Draper, I. Horváth, K. F. Liu, S.
Tamhankar, and J. B. Zang: hep-ph/0406196.
6) T. T. Takahashi, T. Kunihiro, T. Onogi, and T. Umeda:
hep-lat/0410025.
7) N. Ishii, T. Doi, H. Iida, M. Oka, F. Okiharu, and
H. Suganuma: hep-lat/0408030; hep-lat/0409121; heplat/0410022.

RIKEN Accel. Prog. Rep. 38 (2005)

Static quark potential in Nf = 2 dynamical domain-wall QCD†
K. Hashimoto∗ and T. Izubuchi∗
We calculate the static quark potential in two-ﬂavor
dynamical quark lattice QCD using DBW2 gauge1)
and domain-wall fermion (DWF)2) actions. One of the
purposes is to determine of lattice spacing a from Sommer scale r0 = R0 a ≈ 0.5 fm.3)
 between inﬁnitely heavy
The static potential V (R) in spatial direcquark and anti-quark separated by R T ):tion is obtained from the Wilson loop W (R, T ) = C(R)e −V (R)T+ (“excited states ),(1)W (R,

 is the overlap with the “ground state.”
where C(R)We employ DBW2 and Nf = 2 DWF actions with
β = 0.80, Ls = 12, M5 = 1.8, mdyn a = 0.02, 0.03,
0.04, (941, 559, 473 conﬁgurations respectively), corresponding to mπ /mρ = 0.54(1), 0.60(1), 0.65(1) on
163 ×32 lattices. Inverse of the lattice spacing from rho
4)meson mass in the chiral limit is a−1mρ = 1.69(5) GeV.
5)
We implement Bresenham algorithm, which allows
us to obtain the geodesic path connecting the ends of = (N1 , N2 , N3 ) on lattice, where Ni (i = 1, 2, 3)R
are any three integers, and APE smearing6) for spatial
links. The smearing coeﬃcient and iteration time are
tuned: (c, n) = (0.50, 20) for all mdyn to maximizeC(R).
 is obtained from (1):The static potential V (R) T ) = ln W (R, T )/W (R, T + 1)
V (R,
(2)

introduced to correct rotational symmetry breaking(c1 = −1.4069 for DBW2).
(II) R0 is obtained from calculating the gradient of
 To solve Eq. (3), we interpolate
the potential, ∇V (R).
 = f0 + f1 R−2 , between two
by a function: |∇V (R)|neighboring points.
Figure 1 shows the Sommer scale R0 = r0 /a for
dynamical quark mass, mdyn + mres , where mres a =of the ﬁts are extracted at
0.00137(4).4) Our results√
T = 5 and R ∈ [ 3, 8] for all mdyn , and gradientof the potential at same T . R0 in the chiral limit,
mdyn +mres → 0, is obtained by a linear extrapolation.
R0 = 4.24(6), 4.28(5) and 4.25(9) from ﬁts with l = respectively. These results are
0, l = 0, and ∇V (R)consistent within statistical errors. From r0 = 0.5 fm
as an input, our main value is a−1
r0 = 1.69(2) from ﬁt
with l = 0.
−1
Comparing a−1
r0 with amρ = 1.69(5), these values are
consistent within errors. For quenched DBW2 simula−1 7)
The latticetion, a−1
r0 is about 10% larger than amρ .
spacings from r0 and mρ become much closer by dyanmical quark eﬀect.
Although we do not show details here, we observe
Coulomb term coeﬃcient α becomes larger and the behaves diﬀerently byoverlap with ground state C(R)7)
dyanmical quark eﬀect too.

by neglecting the excited states. T = 5 is selected as
the smallest time at which the excited states contribu
tion becomes negligible in V (R).
The Sommer scale R0 ,
dV (R) 
 2 |∇V (R)|
 
R2
=
|
R|
= 1.65, (3)

dR 
|R|=R
0
R=R0

 by the several methods to nailis extracted from V (R)down the systematic errors:(I) R0 is obtained from a ﬁtting function:
 

1
1
α

−
,
V (R) = V0 − + σR − l

R
R
R

1.65 − α
R0 =
,
(4)
σ
 is the lattice Coulomb potential,
where [1/R]
 
π

1
d3 k
exp(ik · R)
=
,
2
4
2

R
−π 8π
i sin (ki /2) − 4c1 sin (ki /2)(5)†∗Work done with the RBC Collaboration. This work is supported by RIKEN Super Combined Cluster at RIKEN.
Institute for Theoretical Physics, Kanazawa University

Fig. 1. R0 vs. (mdyn + mres )a for three types of analysis.
 is preliminary. Error is only statistical.
“from ∇V (R)”

References
1) T. Takaishi: Phys. Rev. D 54, 1050 (1996); QCD-TARO
Collaboration, P. de Forcrand et al.: Nucl. Phys. B 577,
263 (2000).
2) D. B. Kaplan: Phys. Lett. B 288, 342 (1992); Y.
Shamir: Nucl. Phys. B 406, 90 (1993); V. Furman and
Y. Shamir: Nucl. Phys. B 439, 54 (1995).
3) R. Sommer: Nucl. Phys. B 411, 839 (1994).
4) RBC Collaboration, T. Izubuchi: hep-lat/0410034;
RBC Collaboration, Y. Aoki et al.: hep-lat/0411006.
5) B. Bolder et al.: Phys. Rev. D 63, 074504 (2001).
6) M. Albanese et al.: Phys. Lett. B 192, 163 (1987).
7) RBC Collaboration, K. Hashimoto and T. Izubuchi:
hep-lat/0409101.

199

RIKEN Accel. Prog. Rep. 38 (2005)

Nucleon structure in lattice QCD with domain wall fermions†
Y. Aoki,∗1 T. Blum,∗2 S. Ohta,∗3 and K. Orginos∗4
This year, numerous new results have been obtained from our lattice QCD numerical investigations of the structure of nucleon with domain wall
fermions (DWFs) quark action and DBW2 gauge action.1) Quenched calculations without virtual creation
and annihilation of quark-antiquark pairs are almost
complete for the moments of nucleon structure functions2) and nucleon decay matrix elements,3) both with
nonperturbative renormalizations. Dynamical calculations including virtual creation and annihilation ofquark antiquark pairs with two degenerate quark ﬂavors are ongoing for the nucleon axial charge, momentsof structure functions, and nucleon decay matrix elements.
In all these calculations, the ﬂavor SU(2)×SU(2) chiral symmetry is very important. In this regard, the useof DWF quarks is indispensable because the more conventional Wilson and staggered quarks badly violate
either the ﬂavor or the chiral symmetry or both andmakes the use of nonperturbative renormalizations,4)
which is essential for the results reported in this article, impractical. The DBW2 action facilitates the useof DWF.1)
One of the simplest demonstrations of the powerof nonperturbative renormalization combined with the
DWF and DBW2 actions is the calculation of nucleon
axial charge.5) Its ratio to the vector charge, gA /gV , isnaturally renormalized. Since this had been reported
in detail in the past years, we simply note here thatthe new, dynamical calculations are consistent with
the quenched ones, although the error is rather large.
The quark mass dependence is very mild, and the chiral extrapolation is consistent with the experimental
value.
The nucleon structure functions are measured in, forexample, the lepton deep inelastic scattering oﬀ nucleons. What are accessible in lattice QCD are their
moments. We have been calculating some of these moments that do not require ﬁnite momentum transfer.
This year, their nonperturbative renormalizations in
the quenched case have been completed, and found to
typically exhibit 10% eﬀects. The quark mass dependence is again mild. Corresponding dynamical calculations are ongoing.
Yasumichi Aoki has been driving our calculations on
†
∗1
∗2
∗3
∗4

200

Condensed from the presentations at Int. Symp. Lattice
2004, Batavia, USA, 2004-7
Department of Physics, University of Wuppertal, Germany
Department of Physics, University of Connecticut, USA
Theory Division, Institute of Particle and Nuclear Studies,High Energy Accelerator Research Organization (KEK)
Center for Theoretical Physics, Massachusetts Institute ofTechnology, USA

nucleon decay matrix elements. The grand uniﬁed theories generally predict that the nucleon decays into ameson and a lepton. The experiments are now entering
the stage where the researchers will be distinguishingamong the various supersymmetric versions of these
theories. Thus accurate calculations of the associatedhadronic matrix elements are increasingly important.
Here again, the lattice QCD numerical calculations are
the only reliable tools. Two methods have been proposed: direct and indirect. In the direct methods, all
the relevant quantities are calculated on the lattice. In
the indirect methods, a chiral perturbation is used toreduce the calulations to the derivations of only two
coeﬃcients on the lattice. Earlier attempts of calculating the quantities on the lattice resulted in a rather
large disagreement between the two methods of up to
50%. The explicit violation of chiral symmetry in thesecalculations, however, made them inconclusive. Our
quenched calculations on this issue are now complete,
and are summarized in Fig. 1. It has been conﬁrmedthat the direct and indirect methods disagree.

Fig. 1. Nucleon decay matrix elements. The results of direct and indirect methods disagree with each other.

References
1) See for example, Y. Aoki et al.: Phys. Rev. D 69, 074504(2004).
2) RBCK Collaboration, S. Ohta and K. Orginos:
arXiv:hep-lat/0411008.
3) RBC Collaboration, Y. Aoki: arXiv:hep-lat/0409114.
4) T. Blum et al.: Phys. Rev. D 66, 014504 (2002).
5) RBCK Collaboration, S. Sasaki, K. Orginos, S. Ohta,
and T. Blum: Phys. Rev. D 68, 054509 (2003).

RIKEN Accel. Prog. Rep. 38 (2005)

Neutron electric dipole moment with domain wall quarks
F. Berruto,∗1 T. Blum,∗2 K. Orginos,∗2,∗3 and A. Soni∗1
One of the most intriguing aspects of QCD is thatit allows a T- and P-odd, gauge
invariantinteraction

g2= iθQ, where
term, Sθ = d4 x iθ 32π
2 tr G(x)G̃(x)Q is the topological charge of the QCD vacuum. Thus
QCD does not respect CP. One of the best ways tomonitor this is by searching for the neutron electric
dipole moment, dN . dN = |dN | < 6.3 × 10−26 e-cm
from current experiments.1) Using this experimental
bound along with various model estimates of dN 2–4)
implies that the CP-odd parameter in the QCD actionis unnaturally small, θ ≤ 10−10 . Since there is no reason for this number to be so diﬀerent from unity, its
minuteness requires extraordinary ﬁne-tuning. This isoften termed the Strong CP problem. To translate theabove experimental bound to a constraint on the fundamental θ parameter requires evaluation of nucleon
matrix elements, wherein lattice QCD enters.
There are two important elements to our computational strategy: (1) Compute the matrix elementsof the electromagnetic current between nucleon states,p , s|J µ |p, sθ = ū(p , s)Γµ (q 2 )u(p, s), where2F2 (q )
Γµ (q 2 ) = γµ F1 (q 2 ) + i σµν q ν2m+ γµ γ5 q 2 − 2mγ5 qµ FA (q 2 )+σµν q ν γ5(1)F3 (q 2 ),2m

and use projectors to obtain linear combinations of F1and F2 ,GE (q 2 ) = F1 (q 2 ) +q2
F2 (q 2 )(2m)2

GM (q 2 ) = F1 (q 2 ) + F2 (q 2 ),

(2)
(3)

and F3 (q 2 )/2m. By forming ratios of GM (q 2 ) andF3 (q 2 ) with GE (q 2 ) and taking q 2 → 0, we ﬁndboth magnetic and electric dipole moments, respectively: e(F1 (0) + aµ )/2m and dN = eF3 (0)/2m (note,
GE (0) = F1 (0) = 1 and 0 for the proton and neutron,
respectively, and aµ ≡ F2 (0) is the anomalous magnetic moment). In the above q 2 ≤ 0, and m is thenucleon mass.
(2) Expand p , s|J µ |p, sθ to lowest order in θ andcompute F3 (q 2 ) in each topological sector ν, and thenaverage over all sectors with weight Qν . Our method
requires extrapolation of the form factors to q 2 = 0
from non-vanishing values of q 2 .
We have calculated the ratios of neutron and proton
∗1
∗2
∗3

High Energy Theory group, Brookhaven National Laboratory, USA
Physics Department, University of Connecticut, USA
Center for Theoretical Physics, Massachussets Institute ofTechnology, USA

magnetic to proton electric form factors which become
the dipole moment in question in the limit q 2 → 0.
These results were computed on 280 Nf = 2, msea =0.02, domain wall fermion conﬁgurations (separated by
10–15 trajectories) with mval = 0.04 and 0.08.5) The
lattice size is 163 × 32, Ls = 12, and the inverse lattice spacing in the msea = 0 limit is a−1 ≈ 1.7 GeV.
We have averaged over time slices 14–17 and (equivalent) permutations of momenta, p = (1, 0, 0), (1,1,0),and (1,1,1). Q was computed by integrating the topological charge density after APE smearing the gauge
ﬁelds (20 sweeps with ape weight 0.45).6) We are also
investigating computing the topological charge fromthe index deﬁned from the domain wall fermion Dirac
operator (strictly valid in the limit Ls → ∞).
Approximating the q 2 → 0 value of each with thesmallest value of p2 (= (2π/16)2 ), taking mf = 0.04 as
the physical value of the light quark mass, and aMN =aMP = 0.8989(77) at this quark mass, we obtainaPµ ≈ 1.45(10)aNµ ≈ −1.50(7)dN /(e a θ) ≈ −0.06(15).
Considering the crude extrapolations just described,
these are roughly consistent with the experimental valNues aPµ = 1.79 and aµ = −1.91 (and of course dN ∼ 0).
The error estimates are statistical uncertainties only.
In physical units, dN = −7.4(18.0) × 10−16 θ e-cm, so
our calculation can not yet exclude any of the model
calculations mentioned above. The electric dipole moment of the neutron does not show any signiﬁcant dependence on the quark mass, within relatively large
statistical errors (note, the two valence quark masscalculations are highly correlated). We are striving to
reduce the statistical error on our determination of dN
which has already yielded an interesting ﬁrst-principles
bound on the magnitude of dN . These calculations arein progress.
References
1) P. G. Harris et al.: Phys. Rev. Lett. 82, 904 (1999), andreferences therein.
2) V. Baluni: Phys. Rev. D 19, 2227 (1979).
3) R. J. Crewther et al.: Phys. Lett. B 88, 123 (1979).
4) M. Pospelov and A. Ritz: Phys. Rev. Lett. 83, 2526
(1999).
5) RBC Collaboration, Y. Aoki et al.: hep-lat/0411006.
6) T. DeGrand, A. Hasenfratz, and T. G. Kovacs: Nucl.
Phys. B 520, 301 (1998).

201

RIKEN Accel. Prog. Rep. 38 (2005)

The first results of the dynamical domain wall QCD
T. Izubuchi,∗ for the RBC Collaboration
We report on the ﬁrst large-scale study of two ﬂavor QCD with domain wall fermions (DWF). Simulation has been carried out at three dynamical quark
mass msea = 0.02, 0.03, and 0.04 which corresponds toabout 1/2, 3/4, and 1 mstrange on 163 ×32, or (1.9 fm)3
box, with Ls = 12, domain wall height M5 = 1.8, anda−1 ≈ 1.7 GeV. We choose the DBW2 gauge action at
β = 0.80, by which the drastic reduction of the residual mass, mres , for relatively small Ls ∼ O(10) was
observed in quenched simulation.1)
HMC-Φ algorithm is employed to generate ∼ 5,000
trajectories for each msea . We found several interesting and unique technicalities for DWF dynamical simulation such as 1) the acceptance probability kept large
for the entire msea range, 2) improvements of the acceptance by the new lattice action, 3) factor of two to
three speed up by forecasting the solution of the Diracequation.2) Although these observations are encouraging for DWF simulations with lighter quark masses in
the future, we note that they may only be true forrelatively heavy msea .
For each of three msea , we measure on 94 lattices
separated by 50 trajectories, leaving out the ﬁrst 
600 trajectories to allow the evolution to be thermalized. All quoted errors are from jackknife estimate of
the statistical error, with the correlated ﬁt for hadronpropagators using a single covariance matrix computedon the entire ensemble.
By a linear diagonal extrapolation, msea = mval →0, we found mres = 0.00137(4) or  5 MeV, which islarger than quenched DBW2 values for the same Ls
and a−1 , but it is still an order of magnitude smaller
than the input quark mass.
Pseudo-scalar decay constant, fps , was extracted
from the wall-point pseudo-scalar correlator and linearly extrapolate to the chiral limit, mqval = mqsea = 0
with mqval ≡ mval + mres , mqsea = msea + mres , toobtain an estimation in the chiral limit, f = 0.078(1).
The ﬁt to the next-to-leading order (NLO) partiallyquenched chiral perturbation theory (PQChPT) formula for fps did not describe the data well in the neighborhood of the ﬁt range.3) However, the following results depend on the value of f only mildly, so we will
use the estimation from the linear ﬁt.
As for the mass of the pseudo-scalar mesons andthe vector mesons, it is worth mentioning that a simple linear extrapolation of m2ps to mqval,sea = 0 is zero
within the statistical error. This did not happen in thequenched case: m2ps = 0 at mf ≈ −(2 − 3) × mres .1)
This is consistent with the diﬀerence between chiral logarithms (m2ps /mq ∼ 2B0 + cmq log mq ) vs the∗202

Institute for Theoretical Physics, Kanazawa University

Fig. 1. m2ps /(mval + mres ) as a function of mval for eachmsea , and the NLO fit curves from msea,val ≤ 0.03.

quenched one (m2ps /mq ∼ log mq ) at small mq .
A linear extrapolation of the three vector meson
mass points mval = msea , yields a−1 =1.69(5) GeV at
the quark mass, mf = m̄ = 0.0002(1) corresponding
to the neutral pion mass using NLO ﬁt. Similarly, butusing the NLO ChPT prediction for non-degeneratevalence quarks, ms = 0.045(3) is obtained from thephysical kaon mass. The coeﬃcients in the NLO formula for non-degenerate quarks are determined by theﬁt of the degenerate quark meson. It is important
to note that m̄ and ms as deﬁned above are barequark masses; the renormalized quark mass is deﬁned
as Zm mq = Zm (m + mres ), where Zm ∼ 1/0.6 is ascheme and scale dependent renormalization factor.4)
Extrapolating the measured decay constant at thepartially quenched points (mval,sea ≤ 0.04) using thelinear ansatz to m̄ and ms , we ﬁnd fπ = 134(4) MeV,
fK = 157(4) MeV, and fK /fπ = 1.18(1), which agree
better with experiment than quenched simulations.1)
We have tried the NLO ChPT ﬁt for the mass anda simple linear ﬁt for the decay constant. The results
for the physical decay constants are closer than thosein quenched DWF simulation. For further details of
the simulations and results, we refer the reader to thepaper.3)
References
1) Y. Aoki et al.: Phys. Rev. D 69, 074504 (2004); heplat/0211023.
2) R. C. Brower et al.: Nucl. Phys. B 484, 353 (1997);
hep-lat/9509012.
3) RBC Collaboration, Y. Aoki et al.: hep-lat/0411006.
4) RBC Collaboration, C. Dawson: Nucl. Phys. B (Proc.
Suppl.) 128, 54 (2004); hep-lat/0310055.

RIKEN Accel. Prog. Rep. 38 (2005)

Perturbative determination of mass-dependent renormalization andimprovement coeﬃcients for the heavy-light vector and axial-vector
currents with relativistic heavy and domain-wall light quarks†
N. Yamada, S. Aoki,∗ and Y. Kuramashi∗
In the lattice study of heavy-light physics, combining
the relativistic heavy (RH) quark1) and the domainwall (DW) light quark2) is a promising choice to successfully describe heavy and light quarks, respectively.
The mass-dependent O(a) improvement coeﬃcients forthe heavy-light vector and axial-vector currents consisting of this set of quark actions are calculated at
the one-loop level. The detailed descriptions for the
calculation are available in Ref. 3.
The improvement coeﬃcients for the heavy-lightvector current are deﬁned as follows:
Vµlat,imp ,VµMS = ZVMS−lattµ
ZVMS−latt= Zwf 1 − g 2 ∆Vµ ,
µ
−
2 − +
Vµlat,imp = q̄γµ Q − g 2 c+Vµ ∂µ {q̄Q} − g cVµ ∂µ {q̄Q}2 H− g 2 cLVµ {∂i q̄}γi γµ Q − g cVµ q̄γµ γi {∂i Q}+ O(g 4 ),→ ←where ∂µ± =∂µ ± ∂µ, q and Q denote lattice light andheavy quark ﬁelds, respectively, and Zwf is a known
factor related to wave function renormalizations. The
exact chiral symmetry held by the lattice light quark
action provides an exact relationship between the improvement coeﬃcients for the vector and axial-vector
currents regardless of the lattice heavy quark action.
Thus we do not need to calculate those for the axialvector current once the above coeﬃcients have been
determined.
Figure 1 shows the mQ (0) dependence of ∆V0 (circles) for three diﬀerent gauge actions, the plaquette,
Iwasaki and DBW2. The results for M5 =0.5, 1.1 and
1.7 are shown as examples. The ﬁt (solid lines) reproduces the data very well in the entire ranges of(0)
mQ and M5 as shown in the ﬁgure. The other coeﬃ, are also obtained successfully, althoughcients, c±,H,LVµwe omit the detailed explanations because of limited
space.
We examined two methods of improving the perturbation series, namely the mean ﬁeld improvement(MF) and the quasi nonperturbative improvementwith MF (QNP+MF) using the nonperturbative Zfactor for the light-light vector current. The reorganized coeﬃcients of ∆V0 , ∆MF
V0 (triangle-up) and(triangle-down),
areplotted in Fig. 1. It∆QNP+MFV0
is noted that for the nonimproved coeﬃcients the size
†
∗

(0)

QNP+MF
Fig. 1. mQ dependence of ∆V0 , ∆MF
with
V0 and ∆V0
the plaquette, Iwasaki and DBW2 gauge actions from
top to bottom.

of the one-loop coeﬃcient largely depends on the gauge
action, whereas when QNP and MF are introduced together, the dependence decreases. It is also interesting to observe that the mean ﬁeld improvement makes
the mQ dependence smaller. Similar ﬁndings were obtained for the improvements of ∆Vk as well.
References
1) S. Aoki, Y. Kuramashi, and S.-I. Tominaga: Prog.
Theor. Phys. 109, 383 (2003).
2) V. Furman and Y. Shamir: Nucl. Phys. B 439, 54(1995).
3) N. Yamada, S. Aoki, and Y. Kuramashi: arXiv:heplat/0407031.

Condensed from the Proc. Lattice 2004, Batavia, USA,2004-7 (Elsevier, 2004), p.719.
Institute of Physics, University of Tsukuba

203

RIKEN Accel. Prog. Rep. 38 (2005)

Twisted mass QCD, O(a) improvement and Wilson chiralperturbation theory
S. Aoki∗ and O. Bär∗
We point out a caveat in the proof for automaticO(a) improvement in twisted mass lattice QCD at
maximal twist angle. With the deﬁnition for the twist
angle previously given by Frezzotti and Rossi,1) automatic O(a) improvement can fail unless the quark
mass satisﬁes mq  a2 Λ3QCD . We propose a diﬀerent
deﬁnition for the twist angle which does not require a
restriction on the quark mass for automatic O(a) improvement. In order to illustrate explicitly automaticO(a) improvement we compute the pion mass in thecorresponding chiral eﬀective theory. We consider different deﬁnitions for maximal twist and show explicitly
the absence or presence of the leading O(a) eﬀect, depending on the size of the quark mass.
A crucial assumption for automatic O(a) improvement in twisted mass lattice QCD at maximal twist
angle is that the critical mass M = cr is odd underr → −r. According to the analysis of the Wilson chiralperturbation theory (WCPT),2,3) however, the criticalmass should have the following structure:(1)
Mcr (r) = Modd (r) + a2 c Meven (r) ≡ Mcr
(r)

(1)

where Modd (r) is odd and Meven (r) is even under r →−r. Performing the transformation r → −r we obtaina second independent critical quark mass:(2)(r). (2)−Mcr (−r) = Modd (r)−a2 c Meven (r) ≡ Mcr

With this form of the critical quark masses, thetwisted mass average at the maximal twist becomesπ  1π= O r, mq , ω =OT A r, mq , ω =
2
2 
2

π
(3)
+O −r, m̂q , ω = + ω̂ ,2where we have deﬁnedm̂q = m2q + (2a2 c Meven (r))2 ,tan ω̂ =2a2 c Meven (r)
,
mq

(4)
(5)

for the subtracted quark mass mq and the twisted massµ. The twist average is therefore no longer equal to
the Wilson average. In order to show that the twist
average is automatically O(a) improved, the new mass
parameter m̂q and the angle ω̂ must satisfy the conditionsm̂q = mq + O(a2 ),ω̂ = O(a2 ).

(6)These conditions are met if the quark mass satisﬁes∗

204

Graduate School of Pure and Applied Sciences, Universityof Tsukuba

the bound mq  a2 Λ3QCD where ΛQCD is the typical
QCD scale.
In order to remove the condition on mq for the automatic O(a) improvement, we propose an alternative deﬁnition for the twist angle. With the deﬁni(1)(2)
Mcr (r) + Mcr (r)= −M cr (−r)
tion that M cr (r) =
2
(1)
(2)
Mcr (r) − Mcr (r)= ∆Mcr (−r), weand ∆Mcr (r) =2deﬁne mq and µ as
m = [mq + ∆Mcr (r)] cos ω  + M cr (r),µ = [mq + ∆Mcr (r)] sin ω  .

(7)
(8)

Here ω  is an alternative deﬁnition of the twist angle.
It is easy to see that the automatic O(a) improvement
can be proven at ω  = π/2 without any restrictions on
the size of mq .4)
Using the WCPT for the 2 ﬂavor QCD, we havecalculated the pion masses to illustrate explicitly theabove general argument.4)
We ﬁrst consider the original deﬁnition of the maximal twist (ω = π/2). For µ ≥ O(a) we havem2π1,2 = 2Bµ,m2π3 = m2π1,2 + 2c2 a2(9)where B and c2 are the low energy constants in the
WCPT.2,3) and π i (i = 1, 2, 3) represents the triplet
pion. In this case there is no O(a) scaling violation,
so that the automatic O(a) improvement is achieved.
For 2Bµ  2c2 a2 , on the other hand, we havem2π1,2 = (c2 a2 )1/3 (2Bµ)2/3 ,m2π3 = 3m2π1,2 .

(10)

The above behaviour that m2π = O(µ2/3 ) is diﬀerent
from the behaviour in the continuum theory. Therefore
the automatic O(a) improvement does not hold in thiscase.
At the maximal twist for our alternative deﬁnition(ω  = π/2), we havem2π1,2 = 2Bµ,m2π3 = m2π1,2 + 2c2 a2(11)

for all values of µ. Therefore the automatic O(a) improvement holds without any restrictions on the sizeof the quark mass, as discussed before.
References
1) R. Frezzotti and G. C. Rossi: JHEP 0408, 007 (2004).
2) S. R. Sharpe and R. J. Singleton: Phys. Rev. D 58,
074501 (1998).
3) S. Aoki: Phys. Rev. D 68, 054508 (2003).
4) S. Aoki and O. Bär: hep-lat/0409006.

RIKEN Accel. Prog. Rep. 38 (2005)

Status of the QCDOC computer project
P. A. Boyle,∗1,∗2 D. Chen,∗3 N. H. Christ,∗2 M. Clark,∗1 S. D. Cohen,∗2 C. Cristian,∗2 Z. Dong,∗2 A. Gara,∗3
B. Joó,∗1 C. Jung,∗2,∗4 C. Kim,∗2 L. Levkova,∗2 X. Liao,∗2 G. Liu,∗2 R. D. Mawhinney,∗2 S. Ohta,∗5
K. Petrov,∗2,∗4 T. Wettig,∗6 and A. Yamaguchi∗2
The QCDOC (QCD On a Chip) computer
project1–5) aims at providing a computational powerin the range of tens of TFlops optimized for numericalinvestigations of lattice QCD (Quantum Chromodynamics). It started in 1999 as a joint research projectof Columbia University, IBM Research and RIKEN.
The British UKQCD Collaboration joined soon afterwards.
Each QCDOC configuration will involve tens of
thousands of computational nodes each communicating with its twelve nearest neighbors in a sixdimensional hypercubic network. A single QCDOC
computational node consists of a single application
specific integrated circuit (ASIC) with a) a 500 MHz,
32-bit PowerPC 440 processor core, b) a 64-bit, 1
GFlops floating-point unit, c) 4 MBytes of embeddedDRAM memory, d) controllers for embedded and external memories, e) a nearest-neighbor serial communication unit (SCU) with total latencies of 350 ns (550 ns)
for supervisor (regular) transfers that will occur simultaneously in the 12 independent directions and an aggregate bandwidth of 12 Gbit/s, and f) other components such as an Ethernet controller. Two such ASICs
are mounted on a daughterboard, together with two
double data rate (DDR) SDRAM modules (one per
ASIC, up to 2 GB each). Thirty-two daughterboards
are mounted on a motherboard, and eight motherboards are mounted in a crate with two backplanes.
The final machine consists of a certain number of suchcrates.
Last year, we reported the completion of the ASIC
design, the successful production and verification of
prototype ASICs, and then the productions and verifications of the daughtercards and motherboards. During the past year we successfully assembled and verified aircooled and watercooled crates that accommodate eight motherboards each. The operating system
and application softwares have been developed using
these configurations capable of O(1) TFlops computational speeds to the level where physics research can
now be undertaken. Indeed an exploratory set of calculations in search of optimal parameters for a very
∗1
∗2
∗3
∗4
∗5
∗6

Department of Physics and Astronomy, University of Edinburgh, UK
Department of Physics, Columbia University, USA
IBM T. J. Watson Research Center, USA
Department of Physics, Brookhaven National Laboratory,
USA
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Institute for Theoretical Physics, University of Regensburg,
Germany

realistic 2+1 flavor dynamical lattice QCD calculation
with domain wall fermions (DWFs) quark and DBW2
gluon actions are now under way.
In September, we started assembling a 10-TFlops
QCDOC configuration for the UKQCD Collaboration.
This configuration was completed and verified by October 22nd, and shipped to Edinburgh, in the United
Kingdom. Assembly of another 10-TFlops configuration for the RIKEN BNL Research Center was also
started in October, to be completed by the end of
the year (see Fig. 1). Both the UKQCD and RBC
collaborations are launching several physics research
projects using these 10 TFlops computers. In addition, yet another 10-TFlops configuration will be built
at Brookhaven National Laboratory for the American
lattice QCD research community funded by the US
DOE.

Fig. 1. The 24-crate, 10-TFlops configuration of the QCDOC computer for the RIKEN-BNL Research Center
being assembled, as of November 5th, 2004.

References
1) P. A. Boyle et al.: Nucl. Phys. B (Proc. Suppl.) 129,
838 (2004).
2) QCDOC Collaboration, P. A. Boyle, C. Jung, and T.
Wettig: arXiv:hep-lat/0306023.
3) P. A. Boyle et al.: Nucl. Phys. B (Proc. Suppl.) 119,1041 (2003).
4) P. A. Boyle et al.: Nucl. Phys. B (Proc. Suppl.) 106,
177 (2002).
5) D. Chen et al.: Nucl. Phys. B (Proc. Suppl.) 94, 825(2001).

205

RIKEN Accel. Prog. Rep. 38 (2005)

PHENIX Run-4 achievments and future prospects
A. Deshpande,∗ for PHENIX Collaboration
Relativistic Heavy Ion Collider (RHIC) completed
its fourth run (Run-4) in May 2004. Before Run-4
RHIC had achieved luminosities of the order of 1–
3 × 1031 cm−2 sec−1 with an average polarization of∼27%. Both were significantly lower than the design
values. However, in Run-3 PHENIX demonstrated forthe first time that data collected at a polarized collider
at high energy could be used for double spin asymmtry
measurements. The principle measurement resulting
from Run-3 was the double spin asymmetry in π 0 production in p−p scattering at 200 GeV in Center ofMass (CM) energy. This asymmetry is related to thegluon polarization in the proton and is of great interest
as a promising first probe of the gluon spin in the nucleon. Although with large statistical uncertainty, thedouble spin asymmetries in this process were measured
using the PHENIX detector. Further, it was shownthat all systematic uncertainties are small enough toplan future spin measurements at RHIC.1)
The plan for RHIC Run-4 for polarized proton collisions was mainly accelerator driven: to increase thepolarization and luminosity achieved in RHIC. It washence decided early on that the Run-4 pp would be acommissioning run for polarized protons where the accelerator would strive to achieve a new working pointthat resulted in higher polarization and luminosity. At
the end of 5 weeks of commissioning, both these goals
had been reached in short running periods (over fills).
However, it was essential that this be demonstrated
over long running periods over which the detectors
could take data with acceptable background levels. To
confirm the collider’s ability to provide such a working
environment, an extra week of RHIC running was requested and was granted in the period May 7 to May
15, 2004.
Approximately 150 nb−1 were taken during thosephysics data taking 7-days. Out of which some periods were still used for beam quality improvement
and beam studies. Typically evening and night shifts
were utilized for data collection at PHENIX in normal
running conditions. The PHENIX spin rotators werecommissioned early during the commissioning run as
such all the data collected were for double longitudinal scattering. The search for the new working pointby the CAD was successful and resulted in a successful demonstration of routine delivery of 5 × 1031 cm−2
sec−1 with 40% polarization in the yellow beam and
45% polarization in the blue beam. The relative luminosity at PHENIX was studied and evaluated using
the variation of hit multiplicities in the PHENIX Beam∗

206

Department of Physics & Astronomy, State University of
New York-Stony Brook, USA

Beam Counters (BBCs) and the Zero Degree Calorimeters (ZDCs) w.r.t. each other, as had been successfully
done earlier.1)
The PHENIX Run-4 pp data were collected fromMay 10–14, 2004 in 2-shifts-per-day running schedule.
They were analyzed and the double spin asymmetriesin π 0 production were measured. The results are reported in this volume.2) They are consistent with our
published results from Run-31) and are consistent withthe gluon polarization results from fixed target Deep
Inelastic Scatter (DIS) data at ∼30% consistency. The
consistency with more exotic expectations of the gluon
polarization are at the level of 0.1%.1)
So far the beam polarimetry at RHIC had been performed using pC scattering in the Coulomb Nuclear Interference region.3) This method presently relies for its
absolute calibration on a theoretical calculation which
limits the uncertainty with which one can measure theproton beam polarization. One of the most importantgoals of the RHIC Run-4 was the commissioning of theHydrogen gas jet target to be used as an absolute calibration for the RHIC pC CNI polarimeters. This was
successfully achieved and is described in Ref. 4.
As this articles goes to print, preparations for RHIC
Run-5 are well underway. We expect a 9 week physics
run at a peak delivered luminosity of 2.7 pb−1 per
week. Taking a conservative estimate we expect towrite 1/3 of the delivered luminosity to tape for analysis at PHENIX. It is expected that during the physics
run we will routinely have 45–50% beam polarization.
We will have a first robust measurement of the gluon
polarization in the region p2T = 1–5 GeV2 using theπ 0 production asymmetry. A first high statistics measurement of the direct photon cross section in pp scattering will also be possible. We base this confidence
on the already attractive results on such a measurement from Run-45) presented in this volume. While
it is expected that we will use all available time during the physics run for the investigations of polarized gluon distribution, we will be ready during thebeam commissioning period and will request several
days of beam with transverse polarization. We believethat the data collected during such times would be exploratory in nature for the beginning of the transverse
physics at PHENIX.6) With future data analysis needsof PHENIX in mind, we plan to do the Run-5 pp data
production at Computing Center in Japan (CCJ) facility at RIKEN, Wako.7)
A cold/super-conducting siberian partial snake isbeing prepared and will be installed in AGS before thepp Run-5 immediately following the heavy ion running. Although the snake will be commissioned, it is
not expected to benefit the physics program until Run-

6. With that snake in Run-6, it is expected that thepolarization levels will reach > 60–65% and at thattime RHIC spin program will reach its peak. Alongwith this, during the next two years it is also expectedthat there will be a dedicated test of the 500 GeV in
CM energy running. If this is successful, every thingnecessary for the W physics program at RHIC will beneeded to be in place for a Run-8 or 9 for the first results on quark and anti-quark helicities in proton. This
will need an uprgade of the muon trigger capabilities
for PHENIX which is now being proposed.8)
The expected channels for polarized gluon distribution measurements are (in order of their being expected
to be of use:) π 0,± production, inclusive promptphoton production, open-heavy-quark production andγ-jet production. The last two in this list will require an upgrade of PHENIX with a central Silicon
VTX tracker (Si TRK). Si TRK9) is being proposedby PHENIX and will be funded by RIKEN and USDOE. The enhanced tracking capability due to thisdevice will aid the discrimination of heavy-quark andnon-heavy-quark events based on their primary andsecondary vertices. The multiplicity seen by the Si barrel layers is in addition expected to aid in identificationof jet axis allowing for a constraint on the kinematicreconstruction of events with γ-jet final states. This
will be a significant enhancement in PHENIX’s capa-

bility in increasing its ability to measure polarized andun-polarized gluon polarization.
In summary, PHENIX spin program is well on its
way. If the expected beam conditions and proposed
detector upgrades are realized, exciting new data leading to better understanding of the nucleon spin will beavailable in near future.
References
1) PHENIX Collaboration: Phys. Rev. Lett., 93, 202002(2004).
2) Y. Fukao et al.: RIKEN Accel. Prog. Rep. 38, 211(2005).
3) O. Jinnouchi et al.: RIKEN Accel. Prog. Rep. 38, 226(2005).
4) H. Okada et al.: RIKEN Accel. Prog. Rep. 38, 224(2005).
5) K. Okada et al.: RIKEN Accel. Prog. Rep. 38, 209(2005).
6) M. G. Perdekamp et al.: RIKEN Accel. Prog. Rep. 38,
245 (2005).
7) S. Yokkaichi et al.: RIKEN Accel. Prog. Rep. 38, 247(2005).
8) X. Wei et al.: RIKEN Accel. Prog. Rep. 38, 240(2005).
9) J. Asai et al.: RIKEN Accel. Prog. Rep. 38, 235(2005).

207

RIKEN Accel. Prog. Rep. 38 (2005)

Single transverse-spin asymmetry measurement in neutral pion andcharged hadron production at PHENIX
Y. Goto, C. Aidala,∗1 F. Bauer,∗2 M. Grosse Perdekamp,∗3 Y. I. Makdisi,∗4 and K. Okada,for the PHENIX Collaboration
The single transverse-spin asymmetry (AN ) is theleft-right asymmetry of the cross sections in the reactions of a transversely polarized beam on an unpolarized target:
AN =dσLeft − dσRight.
dσLeft + dσRight

In 1990, the Fermilab-E704 experiment showed unexpectedly large AN of pions1) and other particles in reactions of a transversely polarized proton (and antiproton) beam
√ on a proton target at the center of mass energy ( s) of 19.4 GeV in the forward-rapidity region.
In 2002, the RHIC-STAR experiment also showed largeof transversely
AN in the neutral pion production√
polarized proton collisions at s = 200 GeV in theforward-rapidity region.2)
To explain these asymmetries, many possible QCDbased models were developed. One model considers the Sivers eﬀect.3) The Sivers eﬀect is a leftright asymmetry in the transverse momentum distribution of partons inside a transversely polarized nucleon. Another model considers the transversity andthe Collins eﬀect.4) Transversity is a transverse polarization of partons inside a transversely polarized
nucleon. The Collins eﬀect is a left-right asymmetry (analyzing power) in the fragmentation of transversely polarized ﬁnal partons. There is also a modelwith a higher-twist eﬀect.5) It is important to diﬀerentiate these possible eﬀects from each other and extract
physics implication from the observed asymmetries.
The soft physics eﬀect must also be considered. Thisis typically evaluated by the cross-sectional measurement of the same reaction. In lower-energy ﬁxed-target
experiments such as the Fermilab-E704 experiment, it
is questionable whether model calculations based on
next-to-leading-order perturbative QCD (NLO pQCD)
can explain the measured cross sections. On the other
hand, the cross sections measured in collider experiments at RHIC are explained by NLO pQCD calculations very well.6,7) This is the great advantage of collider experiments at RHIC.
At PHENIX, we measured AN of neutral pion andcharged hadron production in the mid-rapidity region.
In this region, both gluon-gluon and quark-gluon reactions of momentum fraction x = 0.03 ∼ 0.1 contributed, where quark transversity should be small andgluon transversity should be zero in the leading twist.
∗1
∗2
∗3
∗4

208

Columbia University, USA
University of California-Riverside, USA
University of Illinois at Urbana-Champaign, USA
Brookhaven National Laboratory, USA

The contributions of the transversity and Collins effect to the AN were negligible in this measurement.
On the other hand, the measurement at STAR2) inthe forward-rapidity region was dominated by quarkgluon reactions, where there was a large contribution
from quark transversity at x ∼ 0.6.
Figure 1 shows the results of our measurements. Systematic errors were evaluated by comparing the independent measurements of two polarized beams ofthe collision and independent measurements of left
and right detectors, and comparing minimum-bias andhigh-energy photon trigger data samples, and store-bystore consistencies of asymmetry values, which were
determined to be small. The results of this evaluation
were conﬁrmed by the “bunch-shuﬄing” technique.8)
The width of the shuﬄed distribution was comparedwith the statistical error on the physics asymmetry.
The systematic errors were determined to be smaller
than the statistical error.
The measured AN was found to be consistent withzero to ±2% in the mid-rapidity region, which is lessthan one-tenth the AN measured at STAR in theforward-rapidity region. The results are expected tobe compared with QCD-based model calculations andto be used to determine many possible eﬀects.

Fig. 1. Results of AN measurements in neutral pion (π 0 )and charged hadron (h+ and h− ) production in the midrapidity region.

References
1) D. L. Adams et al.: Phys. Lett. B 261, 201 (1991);
Phys. Lett. B 264, 462 (1991).
2) J. Adams et al.: Phys. Rev. Lett. 92, 171801 (2004).
3) D. W. Sivers: Phys. Rev. D 41, 83 (1990); Phys. Rev.
D 43, 261 (1991).
4) J. C. Collins: Nucl. Phys. B 396, 161 (1993).
5) J. W. Qiu and G. Sterman: Phys. Rev. D 59, 014004(1999).
6) C. Brourrely and J. Soﬀer: Eur. Phys. J. C 36, 371(2004).
7) S. S. Adler et al.: Phys. Rev. Lett. 91, 241803 (2003).
8) Y. Fukao et al.: RIKEN Accel. Prog. Rep. 38, 211(2005).

RIKEN Accel. Prog. Rep. 38 (2005)

Measurement of prompt photons in√
s = 200 GeV pp collisions

K. Okada, Y. Akiba, A. Bazilevsky,∗1 Y. Goto, T. Horaguchi, K. Nakano,∗2 and H. Torii,
for the PHENIX Collaboration
Prompt photon production in proton-proton collisions is a good probe for investigating the parton structure of protons. Its leading subprocess is gluon-quark
Compton scattering. In polarized proton-proton collisions at RHIC, it is a golden process for accessing thespin structure function of gluons in protons.
PHENIX is one of two multipurpose detectors at
RHIC.1) It has electromagnetic calorimeters (EMCal)in the mid-rapidity region (|η| < 0.35). The EMCal
has such a ﬁne granularity (10 × 10 mrad2 ) that it canidentify background photons by reconstructing the π 0mass eﬀectively. In addition, PHENIX has a tracking
system which is useful for rejecting background clusters produced by charged hadrons. Data were collectedwith a minimum bias trigger provided by the beambeam counter (BBC) and with an EMCal trigger. By
requiring high-energy cluster with the EMCal trigger,
event condensation by a factor of 120 was achieved.
The EMCal trigger becomes fully eﬃcient for clusters
with an energy of above 3 GeV. This report is basedon the luminosity of 266 nb−1 obtained in the RHIC
proton-proton run in May 2003.
The prompt photon signal is obtained by subtracting known backgrounds from all EMCal clusters. The
contribution of hadronic interactions is rejected using a photon shower shape cut and by requiring thatno charged track is associated with the cluster. The
dominant source of the background is two photon decay of π 0 ’s. This background is estimated by reconstructing π 0 ’s with two photon invariant mass. If only
one of the two decay photons from π 0 is detected, it
fakes a prompt photon signal. This probability mainly
depends on the geometrical acceptance and kinematics of π 0 decays, which can be well reproduced by
a Monte-Carlo simulation. The number of photons
from hadronic decays other than π 0 ’s is estimated on
the basis of the total number of π 0 ’s. Thanks to thehighly segmented EMCal, two photon cluster merging for high pT π 0 is not a problem in our pT region.
Of all photon clusters, 50(20)% are tagged as photons
from π 0 , and 85(30)% are estimated as photons fromhadrons at pT = 5(16) GeV/c. The uncertainties of energy scale, of π 0 extraction, and of the ratio of hadronproduction to π 0 production are sources of systematic
error. After the yield extraction, correction factors
such as acceptance, eﬃciency, luminosity, and BBC
trigger bias are applied to calculate the cross section.
Figure 1 shows our measurement results of prompt
photon cross section as a function of pT . Curves∗1∗2

Brookhaven National Laboratory, USA
Tokyo Institute of Technology

Fig. 1. Prompt photon cross section as a function of pT .

show NLO pQCD calculations with 3 diﬀerent scales.2)
The theory agrees well with our experimental measurements.
Figure 2√shows the same data as a function ofxT (≡ 2pT / s) superimposed on other experimental√ 5
measurements scaled by s . The agreement seen in
Fig. 2 indicates a consistency
measurements.
√ amongn
The index n = 5 in the scale s is close to the naive
expectation (n = 4) for a point-like process. The small
deviation from n = 4 can be attributed to the scaling violation, and it can be explained by perturbative
QCD.

Fig. 2. Our results with other experimental measurements√ 5
as functions of xT with a scale of s . Our range in xT
is from 0.05 to 0.17.

References
1) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
2) Private communication with W. Vogelsang.

209

RIKEN Accel. Prog. Rep. 38 (2005)

Measurement of prompt photon cross section in proton-proton√
collisions at s = 200 GeV by isolation cut method
T. Horaguchi,∗ Y. Akiba, A. Bazilevsky, Y. Goto, K. Nakano∗ K. Okada, and H. Torii,
for the PHENIX Collaboration
Polarized proton-proton collisions at the Relativistic
Heavy-Ion Collider (RHIC) can provide information on
the spin structure of the nucleon. Prompt photons at ahigh pT are produced mainly by quark-gluon Compton
scattering (gq → γq). The measurement of the direct
photon cross section is a testing ground of perturbative
QCD, and it provides us the polarized and unpolarized
gluon distributions in the nucleon.
In PHENIX,1) we have collected data with an integrated luminosity of 0.15 pb−1 for transversely polarized proton-proton collisions with 15% average polarization in the run of 2001–2002 and 0.35 pb−1 forlongitudinallypolarized collisions in the run of 2003 at√
s = 200 GeV with 27% average polarization.
We analyze the 2003 data collected in PHENIX tomeasure the prompt photon cross section in protonproton collisions at RHIC.
The electromagnetic
calorimeter consists of two subsystems, six sectors oflead scintillator calorimeter and two sectors of lead
glass calorimeter. It is located at a radial distance ofapproximately 5 m from the beam line. Each of these
sectors covers the pseudorapidity range of |η| < 0.35
and the azimuthal angle of φ = 0.4 rad. In this analysis, we use four lead scintillator sectors in the Westarm.
To measure the prompt photon cross section, we employ two methods. One is the subtraction method2)
and the other is the isolation cut method. In this paper, we will focus on the isolation cut method. Thismethod requires that the prompt photon candidate is
not accompanied by any other particle inside a cone ofa certain radius R centered on the photon direction. R
is deﬁned as
(1)
R = ∆φ2 + ∆η 2 ,processes. While the prompt photon from jet fragmentation (Fig. 1 (b)) is suppressed by the cut, most of theprompt photons from quark-gluon Compton scattering(Fig. 1 (a)) can satisfy the cut.
Figure 2 shows the prompt photon cross section as
a function of photon pT measured by the subtraction
method (dot) and isolation cut method (open square).
The shaded box represents systematic errors. Because
the isolation method decreases the background contribution, the systematic uncertainty can be suppressedcompared with the subtraction method. We expectthat the isolation method suppresses the prompt photon from jet fragmentation, which is predicted to occupy the cross section by 30%. However, the present
result obtained by the isolation method is not so diﬀerent as we expected. This indicates whether the isolation cut does not suppress the prompt photon from jet
fragmentation or the cross section of the prompt photon is dominated by quark-gluon Compton scattering.
It is critical to decrease the background contribution
in the measurement of the polarized gluon distributionfunction. Further analysis is in progress.

Fig. 1. Main contribution (a) and fragmentation contribution (b) to prompt photon production.

where φ is the azimuthal angle and η is the pseudorapidity. We choose R = 0.5 which is suﬃciently large
in PHENIX, and isolation cut conditions as follows;
Ei < Eγ × 0.1,
(2)
Esum =
R<0.5

where Esum represents the sum of energy inside of acone with R = 0.5 and Eγ represents the energy of theprompt photon candidate in the center of the cone.
We expect that the isolation cut around wellidentiﬁed photons at a high pT reduces the backgroundcontribution from hadronic dacays from jet. In addition, the isolation cut can separate photon production∗

210

Department of Physics, Tokyo Institute of Technology

Fig. 2. Prompt photon cross section as a function of photon
pT measured by subtraction method (dot) and isolation
cut method (open square).

References
1) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
2) K. Okada et al.: RIKEN Accel. Prog. Rep. 38, 209(2005).

RIKEN Accel. Prog. Rep. 38 (2005)

Measurement of double helicity asymmetry (ALL ) in π 0 productionin proton-proton collisions at RHIC-PHENIX experiment in Run 4
Y. Fukao,∗1 A. Bazilevsky,∗2 A. Deshpande,∗3 and Y. Goto, for the PHENIX Collaboration
One of the goals of the RHIC-Spin program is tomeasure gluon polarization in the proton. Doublelongitudinal-spin asymmetry (ALL ) in high-transversemomentum (pT ) particle production in polarized
proton-proton collisions is a good probe. During therun in 2004 (Run 4), RHIC was operated using longitudinally polarized proton beams with a center ofmass energy of 200 GeV. The average beam polarization was improved to be 40%, which is approximately
1.5 times higher than that in the run of last year (Run3). Integrated luminosity accumulated at PHENIX1)
was 75 nb−1 . This was approximately one third of the
Run 3 statistics, however we obtained a higher ﬁgureof merit due to a higher polarization. In this report, we
present ALL in the π 0 production of the pT range from
1 GeV/c to 5 GeV/c and at the midrapidity measured
in Run 4.
ALL can be calculated using
ALL =N++ − RN+−
1,
|PB ||PY | N++ + RN+−

R=

L++
, (1)
L+−

where PB and PY are the beam polarization, N is
the yield of π 0 , L is the integrated luminosity, ++(+−) denotes identical (opposite) helicity beams. We
adopted a beam-beam counter (BBC) to measure R.
Its error was evaluated by comparing the BBC counts
with those obtained using a zero-degree calorimeter tobe δR = 5.8 × 10−4 , which corresponds to δALL =1.8 × 10−3 for a beam polarization of 40%.
Beam polarization was measured using a protoncarbon CNI polarimeter.2) The CNI polarimeter assigned 32% to the error of the beam polarization, whichaﬀected the scaling error of double helicity asymmetryby 65%. The PHENIX local polarimeter3) conﬁrmedthat the direction of the proton spin in the PHENIX
collision point was more than 99% longitudinal.
High pT π 0 ’s were collected using a high-pT photon
trigger4) based on an electromagnetic calorimeter witha 4 × 4 tile energy threshold of 1.4 GeV. A charged
particle veto was applied to purify photons and to reduce background (BG) to the π 0 signal utilizing a padchamber in front of the calorimeter. Table 1 shows
statistics of π 0 within a ±25 MeV mass window andfraction of BG under the π 0 peak obtained after the
cut for particle identiﬁcation.
The systematic error of ALL can be evaluated by
the bunch shuﬄing technique. In each shuﬄe, we randomly assigned a beam helicity sign to each bunch
∗1
∗2
∗3

Kyoto University
Brookhaven National Laboratory, USA
Department of Physics and Astronomy, Stony Brook University, USAcrossing. The number of bunch crossings was ∼ 550
since we had 11 ﬁlls each containing ∼ 50 crossings.
This can mimic many experimental data. The ﬂuctuation of ALL generated by a suﬃcient number of shuﬄesshould be a result of the statistics of π 0 and systematics, which depends on bunch and ﬁll. By comparing
the statistical error of ALL with the width of the ALL
distribution obtained by bunch shuﬄing, we found thatsystematics is negligible compared with statistical uncertainty. Note that the systematic error correlated
over all bunches or all ﬁlls cannot be evaluated bythis bunch shuﬄing method. The main contributors
to these errors are the uncertainty of beam polarization and the relative luminosity described above.
Figure 1 and Table 2 show Run 4 results of π 0 ALL
as well as the results of Run 35) and combinations
with statistical errors. Two theoretical curves6) arealso drawn on the ﬁgure. Our results favor the GRSVstandard model.
Table 1. Statistics of π 0 ’s and BG fraction.
pT (GeV/c)
1-2
2-3 3-4 4-5
π 0 statistics (×103 ) 1151 510
91
17
BG fraction (%)
31
13
7
5

Fig. 1. π 0 ALL as a function of pT .
Table 2. π 0 ALL in Run 4, Run 3 and combinations.
pT (GeV/c)
Run 4 (%)
Run 3 (%)
Comb. (%)

1-2
0.0 ± 0.9
−2.7 ± 1.3−0.9 ± 0.7

2-3
0.7 ± 1.0
−1.3 ± 1.3
0.0 ± 0.8

3-4
−1.8 ± 2.2−1.7 ± 2.8−1.8 ± 1.7

4-5
9.7 ± 4.9
0.7 ± 6.2
6.2 ± 3.8

References
1) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
2) O. Jinnouchi et al.: RHIC/CAD Accel. Phys. Note, 171(2004).
3) A. Deshpande et al.: RIKEN Accel. Prog. Rep. 37, 246(2004).
4) K. Okada et al.: RIKEN Accel. Prog. Rep. 36, 248(2003).
5) S. S. Adler et al.: Phys. Rev. Lett. 93, 202002 (2004).
6) B. Jäger et al.: Phys. Rev. D 67, 054005 (2003).

211

RIKEN Accel. Prog. Rep. 38 (2005)

J/ψ production in polarized proton-proton collision at√
s = 200 GeV with PHENIX
N. Kamihara,∗ for the PHENIX Collaboration
Since a puzzle in the spin structures of nucleons
was found by previous lepton deep inelastic scattering experiments, it has become important to measure gluon contributions to the nucleon spin structure(gluon polarization). Although J/ψ production is sensitive to gluon polarization, a theoretical ambiguity in
the J/ψ production mechanism at proton-proton collisions makes it diﬃcult to estimate gluon polarizationfrom the double spin asymmetry (ALL ) of J/ψ production. Therefore, determination of J/ψ production
mechanism is the ﬁrst step to solving the nucleon spin
puzzle. Measuring the J/ψ diﬀerential cross sections
as functions of the transverse momentum and the rapidity can be a good test to aid in understanding theJ/ψ production mechanism.
The PHENIX detector at BNL-RHIC is constructed
to investigate the spin structure of protons and theformation of the quark gluon plasma. There are twomuon spectrometers in the PHENIX which cover thepseudorapidity range from |1.2| to |2.4|.1) Each spectrometer consists of a magnet, a muon tracker (MuTr)
and a muon identiﬁer (MuID). The MuID sits behind
the MuTr and consists of ﬁve layers of steel absorbers
and chambers. The MuID is divided into four parts
along the azimuth (quadrant) and used for the trigger system. Detailed descriptions of the PHENIX detector and the muon trigger system can be found inreferences.1,2)
The dimuon mass spectrums are obtained after thefollowing criteria are met: i) the event vertex pointfrom the Beam-Beam Counter3) is within the detector’s ﬁducial volume, ii) each track hits the diﬀerent
quadrants because the current trigger system cannot
distinguish two tracks in the same quadrant, and iii)
χ2 of track ﬁtting is less than 20.
The dimuons fall into three categories. One is anunlike-sign pair contribution (N +− ), and the others
are like-sign pair contributions (N ++ and N −− ). Since
the unlike-sign pairs include the J/ψ signals and the
combinatorial backgrounds, the like-sign pair spectrum
is used for the estimation of the background contributions. The background is estimated from Eq. (1) since
the shape of the unlike-sign background is, in principle,
identical to the distribution of the geometric averageof the like-sign pairs:√(1)
Nbg = 2Rbg N ++ N −− .

∗212

Department of Physics, Tokyo Institute of Technology

Here, Rbg depends on the correlation between acceptedµ+ and µ− in each event. If there is no correlation
between accepted µ+ and µ− , it is expected to be equal
to 1.4) We determined Rbg by comparing N +− and√N ++ N −− within the pure background region from
0.5 GeV/c2 to 2.5 GeV/c2 . After obtaining Rbg , thenumber of J/ψ signals is deduced.
Figure 1 (A) shows the unlike-sign pair and background mass spectrum. The solid line corresponds tothe unlike-sign events. The dashed line is the estimatedbackground from Eq. (1). Figure 1 (B) shows the J/ψ
spectrum after the background subtraction. The mass
resolution obtained by the Gaussian ﬁt in Fig. 1 (B) is
about 140 MeV. The analysis to obtain the diﬀerential
cross section is ongoing.

(A)

(B)
Fig. 1. (A) The unlike-sign pair and background mass spectrum. The solid line is for the unlike-sign events. The
dashed line is the background. (B) The J/ψ mass spectrum after background subtraction.

References
1) H. Akikawa et al.: Nucl. Instrum. Methods Phys. Res.
A 499, 537 (2003).
2) N. Kamihara et al.: RIKEN Accel. Prog. Rep. 37, 224(2004).
3) M. Allen et al.: Nucl. Instrum. Methods Phys. Res. A
499, 549 (2003).
4) M. C. Abreu et al.: Phys. Lett. B 438, 35 (1998).

RIKEN Accel. Prog. Rep. 38 (2005)√
Measurement of single electron spectrum in s = 200 GeV
p-p collisions at RHIC-PHENIX
M. Togawa,∗1 Y. Akiba, R. Averbeck,∗2 S. Butsyk,∗2 F. Kajihara,∗3 T. Tabaru,
Y. Tsuchimoto,∗3 and W. Xie, for the PHENIX Collaboration

Heavy quarks (charm and beauty) are generated√
mainly through the gluon-gluon fusion process in s =200 GeV proton-proton collisions at RHIC. Thus, perturbative QCD can be tested and the gluon distribution function can be determined by measuring theheavy quark production. However the production
mechanism of heavy
quarks is not yet well known. At√
the Tevatron ( s = 1.8 TeV and 1.96 TeV p-p̄ collisions), the measured cross sections of D- and B-mesons
were larger than those predicted by pQCD.1)a) STARalso measured larger a cross section of D-mesons in√
sN N = 200 GeV p-p and d-Au collisions.3) We consider that these diﬀerences result from the uncertainties of the fragmentation and gluon distribution function.
In the PHENIX experiment, heavy quark production
can be measured precisely with single electrons fromsemi-leptonic decays of charm and beauty mesons.
These measurements can shed new light to understandthe production mechanism of heavy quarks.
Electrons are detected by the two central arms of
PHENIX. A central arm is composed of a tracking
chamber system, a RICH (Ring Imaging CHerenkov
counter) and an EMCal (Electro-Magnetic Calorimeter) system. It covers 90 degrees in azimuthal angle
and |η| < 0.35 in pseudo-rapidity. Electrons are wellidentiﬁed by the RICH detector (Cherenkov thresholdfor π ± being 4.9 GeV/c) and the EMCal. The raw
spectrum is corrected for the geometrical acceptance,
the reconstruction and identiﬁcation eﬃciencies as determined by a detailed GEANT simulation.
The yield of electrons can be categorized into nonphotonic and photonic sources. Nonphotonic electrons
are mainly from semi-leptonic decays of charm andbeauty. Photonic electrons include electrons from the
gamma conversion and Dalitz decays of neutral mesons
such as π 0 and η. To decompose these two sources,
we installed a thin brass photon converter around thebeam pipe and took data as a converter run. The converter increases electrons only from the gamma conversion by a ﬁxed factor which is determined by the radiation length of the converter (1.7%). The eﬀect of theconverter was studied using the GEANT simulation of
∗1
∗2
∗3
∗4
a)

Department of Physics, Kyoto University
Department of Physics, State University of New York-Stony
Brook, USA
Center for Nuclear Study, Graduate School of Science, University of Tokyo
Graduate School of Science, Hiroshima University
Recently, NLO QCD calculation has been improved to agreewith CDF data.2)

the PHENIX detector. By comparing the real datawith the simulation with and without the converter,
the nonphotonic electrons could be extracted. We analyzed 30 nb−1 of the nonconverter data and 47 nb−1of the converter data. These data were taken with a
special electron trigger, which requires a RICH hit andan associated energy deposit in EMCal of more than
400 MeV.
Figure 1 shows the invariant pT spectra of electrons
from semi-leptonic decays of charm and beauty. Small
remaining nonphotonic backgrounds such as Ke3 decay were subtracted from the spectra. Present results(RUN3 data) are plotted as ﬁlled circle points together
with the preliminary result from the previous RUN
period (RUN2: statistics ∼20 nb−1 ) shown by triangles. They are consistent within the error. The curves
show the expected spectra from a pythia calculation4,5)
which is tuned to reproduce the charm production at
SPS and FNAL.6) In our result, the cross section islarger than that of the tuned pythia calculation in thehigh-pT region.
We have used ∼1/10 of all available statistics in thisanalysis. In the near future, comparison of the experimental data with the tuned pythia calculation canbe made with smaller statistical error and the spectrum can be extended to the higher-pT region withhigh statistics.

Fig. 1. The invariant pT spectra of electrons from semileptonic decays of charm and beauty. The filled circles
and triangles show the data corrected in 2003 (RUN3)
and 2002 (RUN2), respectively. The curves show the
expected spectra from the tuned pythia calculation.

References
1) D. Acosta et al.: Phys. Rev. Lett. 91, 241804 (2003).
2) CDF Collaboration: hep-ex/0408020 (2004).
3) J. Adams et al.: nucl-ex/0407006.
4) T. Sjostrand: Comput. Phys. Commun. 82, 74 (1994).
5) K. Adcox et al.: Phys. Rev. Lett. 88, 192303 (2002).
6) G. A. Alves et al.: Phys. Rev. Lett. 77, 2388 (1996).

213

RIKEN Accel. Prog. Rep. 38 (2005)

J/Ψ production in p-p, d-Au and Au-Au and collisions in the
PHENIX muon arms
D. E. Fields∗
Muons are an important probe for both the heavy
ion physics program (focusing on the generation, detection, and subsequent characterization of the quarkgluon plasma (QGP) as well as studying the gluon distribution in nuclear matter) and the spin physics program (measuring the helicity distributions of ﬂavorseparated quarks and antiquarks, as well as the ﬁrst
direct measurement of the gluon polarization in the
nucleon1) ). For these purposes, the most interesting
muons originate from vector meson (J/Ψ, Υ, etc.)
decays, Drell-Yan decays, W -decays, and heavy ﬂavor (c and b) meson decays. PHENIX has implemented a two-arm (North and South) muon spectrometer at high rapidity to supplement the photon, electron and hadron identiﬁcation around mid-rapidity.2)
Although these muon arms are performing well, several
upgrades are planned to improve the trigger rejection
power and to discriminate based on coincident particles (χc → J/Ψ + γ) or oﬀset vertices (c, b → e, µ).
The muon arms have now been operational throughthree separate RHIC runs, where data was taken with
p-p, d-Au and Au-Au collisions. PHENIX has published the results of the J/Ψ analysis for the di-muonsand di-electrons from Run02,3,4) and is in preparation
for the publication of the d-Au and p-p J/Ψ analysis
from Run03. For RHIC Run03, both the North andSouth muon arms were operational and took nominal
integrated luminosities of Lint = 2.74 nb−1 in d-Au
running and Lint = 352 nb−1 in longitudinally polarized p-p running. The p-p data will increase our statistics for J/Ψs by approximately one order of magnitude
over the published Run02 results. The d-Au analysis
will provide insight into the nuclear and initial stateeﬀects on J/Ψ production since measurements weremade simultaneously in the low- and high-x regimes
with respect to the gold nucleus. Preliminary results
for the ratio of d-Au to p-p are shown in Fig. 1. In
addition to this important upcoming paper, analysisof the Run04 Au-Au data has proceeded and the ﬁrst
good measurement of the J/Ψ cross section as a function of centrality in relativistic heavy-ion collisions isforthcoming. A sample of the data quality is shown in
Fig. 2 for a small subset of the total Run04 data set.
The Run04 data anlalysis is nearing completion.

∗

214

University of New Mexico, USA

Fig. 1. Deuteron-Au J/Ψ cross section vs. rapidity (leftpanel) and the ratio of d-Au to p-p cross sections (rightpanel).

Fig. 2. Like-sign and unlike-sign di-muon invariant mass
distributions (top panel) and thediﬀerence between
them (bottom panel) for peripheral Au-Au collisions
showing a clear J/Ψ peak.

References
1) G. Bunce, N. Saito, J. Soﬀer, and W. Vogelsang: Annu.
Rev. Nucl. Part. Sci. 50, 525 (2000).
2) K. Adcox et al.: Nucl. Instum. Methods Phys. Res. A
499, 602 (2003).
3) S. S. Adler et al.: Phys. Rev. Lett. 92, 051802 (2004).
4) S. S. Adler et al.: Phys. Rev. C 69, 014901 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Single electron measurement in the PHENIX
Run3 d+Au experimentF. Kajihara,∗1 Y. Akiba, R. Averbeck,∗2 S. Butsyk,∗2 H. Hamagaki,∗1 K. Ozawa,∗1 T. Tabaru,
M. Togawa,∗3 Y. Tsuchimoto,∗4 and W. Xie,∗5 for the PHENIX Collaboration
Heavy-quark (charm and bottom) measurements
provide valuable information for testing perturbative
QCD (pQCD) predictions.1) The measurements also
impose signiﬁcant conditions on uncertainties in the
Leading Order (LO) and the Next-to-Leading Order(NLO) pQCD calculations of heavy-quark productions
which considerably depend on the gluon distributionfunction.2) In heavy-ion collisions, non-pQCD eﬀects,
such as conventional cold nuclear eﬀects can also modify the gluon distribution, i.e., heavy-quark production. Since such nuclear eﬀects are unknown in highenergy region, it is important to investigate these inﬂuences on the heavy-quark measurements.
Heavy-quark production also has an important rolein the investigation of the hot and dense matter createdin heavy-ion collisions. The heavy-quark momentum
spectrum may be aﬀected by ﬁnal state interactions
such as its energy loss in the dense medium. However,
the energy loss is predicted to be small compared withthat of light quarks with high transverse momentum(pT ) due to the larger quark masses.3) The measurement of high-pT heavy quarks will verify the ﬂavor
dependence of energy loss. For precise measurements,
it is essential to estimate and to subtract the inﬂuenceof the above-mentioned nuclear eﬀects.
The RHIC-PHENIX experiment measured d+Au√
collisions at sN N = 200 GeV in 2003 (called Run3).
We can study cold nuclear eﬀects since no high-energydensity matter is formed. The measurement of single
electrons (e+ or e− ) from semileptonic decays of heavy
quarks is a useful way to investigate heavy-quark production. Inclusive electrons can be categorized into
two groups. The ﬁrst group consists of “photonic”
electrons mainly from (1) Dalitz decays of mesons (π 0 ,etc.) and (2) photon conversion. The second group istermed “nonphotonic” electrons. The decays of charmand bottom quarks are the dominant sources of thesecond group. This report presents the status of thenonphotonic electron measurements.
In the PHENIX, the electron measurements are performed by two central arm spectrometers. Each arm
is composed of a Drift Chamber (DC), Pad Chambers (PC), a Ring-Imaging Čerenkov counter (RICH)
and ElectroMagnetic Calorimeters (EMCal), covering
pseudo-rapidity |η| < 0.35 and π/2 in azimuth (φ).4)
∗1
∗2
∗3
∗4
∗5

Center for Nuclear Study, University of Tokyo
Department of Physics and Astronomy, State University of
New York-Stony Brook, USA
Department of Physics, Kyoto University
Department of Physics, Hiroshima University
Brookhaven National Laboratory, USA

The RICH and EMCal are used for electron identiﬁcation (eID) in the oﬀ-line analysis. They are also used
to form an electron trigger system, called the EMCalRICH Trigger (ERT).5) To evaluate the ERT eﬃciency
for electrons, a trigger simulator was developed in the
PHENIX simulation framework. The simulator was
also used for the low-mass-vector meson analysis.6)
To extract nonphotonic yield N (pT ) by subtracting photonic yield P (pT ), the “converter subtraction” method is applied.7) The Run3 experiment was
performed with/without the installation of a brass
photon-converter (1.68 radiation length) around thebeam pipe. It can enhance photonic yield by a certain factor Rsim . The measured inclusive yield I(pT )can be expressed as I(pT ) = P (pT ) + N (pT ) without the converter and I  (pT ) = Rsim P (pT ) + N (pT )with the converter. Since (1)’s branching ratios andform factors, (2)’s probability, and the materials in
the PHENIX environment are well known, Rsim canbe evaluated with a GEANT-based simulation. N (pT )is given by these two equations. Figure 1 shows N (pT ).
The error bars indicate only statistic errors. The yield
is fully corrected for the trigger eﬃciency, geometrical acceptance, reconstruction and eID eﬃciency thatwere determined by the simulation.
Presently, a more precise simulation is being developed to study systematic errors. The nonphotonic
electrons in the high-pT region (≥ 5 GeV/c) will beanalyzed for the study of bottom quarks.

Fig. 1. The pT distribution of nonphotonic invariant yield(triangle; minimum bias trigger, square; ERT).

References
1) S. Frixione et al.: hep-ph/9702287 (1997).
2) R. Vogt et al.: Z. Phys. C 71, 475 (1996).
3) Y. L. Dokshitzer et al.: Phys. Lett. B 519, 199 (2001).
4) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
5) F. Kajihara et al.: CNS Annu. Rep. 2003, 49 (2004).
6) Y. Tsuchimoto et al.: RIKEN Accel. Prog. Rep. 38, 217(2005).
7) S. S. Adler et al.: nucl-ex/0409028 (2004).

215

RIKEN Accel. Prog. Rep. 38 (2005)

Radial flow study via identified hadrons spectrain Au+Au collisions at RHIC-PHENIX
A. Kiyomichi, for the PHENIX Collaboration
Heavy-ion collisions at relativistic energy oﬀer the
possibility of producing highly compressed stronglyinteracting matter, which may form the quark gluon
plasma (QGP). An identiﬁed hadron provides important information on collision dynamics. The momentum spectra of pions, kaons, and protons are sensitive
to the dynamical evolution of the system and carryinformation on the radial ﬂow velocity and thermal
freeze-out condition.
PHENIX1) is one of the major experiments at RHIC
for measuring a variety of signals from heavy-ion collisions. We have measured the transverse momentum
spectra for π ± , K ± , p and p at mid-rapidity in Au+Au√
collisions at sN N = 200 GeV over a broad momentum range with various centrality selections.2) We havealso measured φ meson production in the K + K − decay channel and compared it with identiﬁed charged
hadron data.3)
In order to deduce radial ﬂow velocity and thermal freeze-out temperature, particle spectra were compared to a functional form, which describes a boosted
thermal source, based on relativistic hydrodynamics.4)
A two–parameter model, termed the “blast-wave”
model is used in this analysis, in which the surface
radial ﬂow velocity (βT ) and freeze-out temperature(Tfo ) are free parameters,
 R
 p sinh ρ dNT∝r dr mT I0
mT dmTTfo0 m cosh ρ 
T
× K1
,
Tfo
where I0 and K1 represent modiﬁed Bessel functions
with ρ being the transverse boost which depends on theradial position according to ρ(r) = tanh−1 (βT ) · r/R.
To study the parameter correlations, a grid of (Tfo , βT )pairs is generated and then a χ2 minimization is performed for each particle type. The experimental data
include the decay of resonance; we add the decay ofmesonic (ρ, η, ω, K ∗ , , ,) and baryonic (∆, Λ, Σ, , ,) resonance eﬀects. The detailed analysis methods are described in Ref. 5.
The ﬁrst ﬁt attempt is performed simultaneously forthe six particle species π ± , K ± , p and p in the range(mT − m0 ) < 1.0 GeV/c2 . The two–dimensional gridsearch results obtained in this analysis for each centrality bin are shown in Fig. 1. The expansion velocity
parameter is seen to decrease moderately toward peripheral collisions and the kinetic freeze-out temperature increases signiﬁcantly, approximately 40%. If
one takes these parameters literally, then radial ﬂow
is weak in the peripheral collisions and the particles

216

Fig. 1. Contour plots for hydrodynamical fit to 200 GeV
single particle transverse momentum spectra. The contour lines are in standard deviation steps.

decouple kinetically from each other at temperatures
close to the chemical freeze-out temperature. This is aphysically reasonable scenario given the small numberof participants in the initial expansion phase.
Figure 2 shows the 10% central spectra and blastwave model ﬁt results. The line drawn through theφ meson spectrum is the model’s prediction obtained
after ﬁtting all other particle species. The shape ofthe φ meson spectrum is reproduced by the same ﬂow
parameters. As a result, the φ meson participates in
the collective ﬂow motion similar to other hadrons.

Fig. 2. Transverse momentum data and best-fit hydrodynamical results for 0–10% centrality bin for 200 GeV
π ± , K ± , p and p, along with prediction for φ transverse
momentum spectrum.

References
1) PHENIX Collaboration, K. Adcox et al.: Nucl. Instrum.
Methods Phys. Res. A 499, 469 (2003).
2) PHENIX Collaboration, S. S. Adler et al.: Phys. Rev.
C 69, 034909 (2004).
3) PHENIX Collaboration, S. S. Adler et al.: to appear
Phys. Rev. C, [nucl-ex/0410012].
4) E. Schnedermann, J. Sollfrank, and U. Heinz: Phys.
Rev. C 48, 2462 (1993).
5) A. Kiyomichi et al.: RIKEN Accel. Prog. Rep. 37, 235(2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Measurement of low-mass vector mesons in nuclear collisions at
PHENIX
Y. Tsuchimoto∗ and Y. Akiba, for the PHENIX Collaboration
It is predicted that in nuclear matter at high baryon
density and/or high temperature, chiral symmetry will
be restored and consequently, the masses and thewidths of the low-mass vector mesons (ρ, ω and φ) will
be modiﬁed. If this phenomenon is observed, it will be
one of the most interesting observations in high-energy
nuclear physics. Some interesting results that suggest
the modiﬁcation of the properties of hadrons in ordinary nucleus matter have been reported.1,2)
The Relativistic Heavy Ion Collider at Brookhaven
National Laboratory provides a great opportunity to
study the properties of mesons in hot and dense matter. We have programs of p + p, d + Au and Au + Au√
collisions at sN N = 200 GeV. Comparison of data indiﬀerent collision systems is important to distinguishin-medium eﬀects. The PHENIX experiment can measure the low-mass vector mesons in both e+ e− andhadronic decay channels within the same acceptanceat mid-rapidity. The e+ e− decay channel carries information on mesons deep inside the hot and dense
matter since an electron is not subject to strong interactions. Thus, comparison of the two decay modes issensitive to the modiﬁcation of the properties of themesons. In this report, we present the measurement of
the low-mass vector mesons in the dielectron channels√
in d + Au collisions at sN N = 200 GeV.
The PHENIX experiment at RHIC recorded about
1 nb−1 of d + Au collisions in the year 2003 run period. The PHENIX detector is described in detail elsewhere.3) Charged particle tracks were reconstructed bydrift chambers and pad chambers. Electron identiﬁcation was carried out using Ring Imaging Cerenkov
detectors (RICHs) and electromagnetic calorimeters(EMC). The dielectron pair data were recorded mainly
by an electron trigger, called ERT (EMC-RICH Trigger), which required a hit in the RICH and an associated energy deposit in the EMC. The data weretaken in two running periods with diﬀerent thresholds
of EMC energy, 600 MeV and 800 MeV. The integrated
luminosity of the two periods was approximately thesame.
Figure 1 shows the dielectron invariant mass distribution. The data from the two running periods are
combined in this ﬁgure. A high background due to therandom combination of unrelated e+ and e− was subtracted by an event mixing method. One can clearlyobserve narrow peaks of φ (at 1020 MeV) and ω (at780 MeV) in the mass distribution. To determine theproduction cross section of the vector mesons, the observed φ and ω yields should be corrected for the detec∗

Fig. 1. Low-mass dielectron mass distribution in d + Au√
collision at sN N = 200 GeV.

tor acceptance, electron ID eﬃciency, and the trigger
eﬃciency. A simulator of the ERT trigger has beendeveloped and incorporated into the GEANT-based
PHENIX simulation program framework.4) We calculated the combined acceptance and eﬃciency using thesimulation program. The results of the acceptance/eﬃciency calculation are shown in Fig. 2. In the next
step, we will determine the invariant cross sections of ωand φ as a function of pT using the acceptances shownin Fig. 2.

Fig. 2. Acceptances for φ → e+ e− in the PHENIX detector. The top and bottom panels are for the ERT
thresholds of 600 MeV and 800 MeV, respectively. The
upper acceptance curves (MB) are for minimum bias
triggers.

References
1) K. Ozawa et al.: Phys. Rev. Lett. 86, 5019 (2001).
2) K. Suzuki et al.: Phys. Rev. Lett. 92, 072302 (2004).
3) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
4) F. Kajihara et al.: RIKEN Accel. Prog. Rep. 38, 215(2005).

Department of Physics, Hiroshima University

217

RIKEN Accel. Prog. Rep. 38 (2005)

Charm Production in Au + Au collisions at√
sN N = 200 GeV†

T. Hachiya∗ and Y. Akiba, for the PHENIX Collaboration
Charm quark production is an important probe of
the hot and dense medium created in high-energy
heavy-ion collisions. Due to its large mass, the charmcross section is calculable via pQCD and the yield issensitive to the initial gluon density. In the central Au+ Au collisions at RHIC, π 0 ’s and charged hadrons
are strongly suppressed at high transverse momentum(pT )1) due to parton energy loss in the medium produced in the collisions. It has been predicted thatcharm quarks suﬀer less energy loss than light quarks
due to the “dead cone” eﬀect.2) This eﬀect can be studied through systematic measurement of open charm pT
spectra.
The measurement of single electrons resulting fromsemi leptonic decays of open heavy ﬂavors (D → e + X
and B → e + X) at low pT is a useful way to study
charm production. The PHENIX experiment3) has aunique ability to measure electrons with a wide momentum range using the ring imaging Čerenkov detector and the electromagnetic calorimeter. We measured single-electron production in Au + Au collisions√
at sN N = 200 GeV.
Inclusive electrons contain two components: “nonphotonic” — primarily semi leptonic decays of open
heavy ﬂavor (charm and bottom), and “photonic” —Dalitz decays of light neutral mesons (π 0 , η, η  , ρ, ωand φ) and photon conversions in the detector material. To separate these two components, a thin (1.7%
X0 ) photon converter was installed around the beam
pipe during a part of the run period. Since the photon
converter multiplies the photonic component of electrons by a ﬁxed factor determined by its radiation
length, we can separate these two components by comparing the dataset with and without the converter.
Figure 1 shows fully corrected pT spectra of nonphotonic electrons for minimum-bias collisions andﬁve centrality bins. PHENIX has also measured theheavy
ﬂavor electron spectrum in p + p collisions at√
s = 200 GeV.4) The lines in Fig. 1 show the bestﬁt curve of this spectrum scaled by TAA for each Au+ Au centrality bin. Here, TAA is the nuclear overlap
function calculated using a Glaubar model.1) Au + Au
spectra are in reasonable agreement with the p + p ﬁt
in all centrality bins.
To quantify the centrality dependence of charm production, we calculated the integrated yield dNe /dyα, where Ncoll(0.8< pT <4.0 GeV/c) and ﬁt it to ANcoll
and A are the number of nucleon-nucleon collisions anda normalization parameter, respectively, and α = 1
is the expectation in the absence of the medium ef†∗

218

Condensed from the article in arXiv:nucl-ex/0409028
Hiroshima University

Fig. 1. Fully corrected pT spectra of heavy flavor electrons
for minimum-bias collisions and five centrality bins.

fects. Figure 2 shows dNe /dy (0.8< pT <4.0) / Ncoll
vs. Ncoll for minimum-bias and ﬁve centrality bins in
Au + Au collisions and p + p collisions. We ﬁnd thatα = 0.938±0.075(stat.) ±0.018(sys.). This shows thatthe total yield of charm electrons for all centralities is
consistent with Ncoll scaling. Our current statistics are
too small to conclude charm suppression at high pT .
In conclusion, we have measured single electrons
from heavy ﬂavor decays in Au + Au collisions at√
sN N = 200 GeV. We observe that the centrality dependence of charm production is consistent with Ncoll
scaling, as is expected for hard processes.

Fig. 2. Charm electron yield (0.8< pT <4.0 GeV/c) scaledby Ncoll as a function of centrality given by Ncoll .

References
1) S. S. Adler et al.: Phys. Rev. Lett. 89, 072301 (2003).
2) Y. L. Dokshitzer and D. E. Kharzeev: Phys. Lett. B
519, 199 (2001).
3) K. Adcox et al.: Nucl. Instrum. Methods. Phys. Res. A
499, 469 (2003).
4) S. Kelly et al.: J. Phys. G 30, S1189 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Muon trigger upgrade with muon cathode strip chambers
K. Aoki,∗ for the PHENIX Collaboration
One of the major goals for the PHENIX detector1)
at the Relativistic Heavy Ion Collider (RHIC) is to enable the understanding of the spin structure of the proton. The proton consists of quarks and gluons, and its
structure should be explained in terms of them. It has
been discovered that only 10–30% of the proton spin iscarried by quark spin,2) which is much smaller than our
naive expectation. The rest of the proton spin should
be carried by gluon spin and orbital angular momentum. It has also been shown that s quarks, which exist
as sea quarks in the proton, have spin anti-parallel tothat of the proton. Sea quarks were thought to carryno quantum number before, thus it is also important
to measure the other sea quark spin contributions aswell as that of s quarks.
W production in pp collisions is a powerful tool toinvestigate the sea quark spin contribution because thereaction depends on both quark ﬂavor and helicity.3)
The process is advantageous because it is a pure electroweak process and free from fragmentation functions.
These features make W production a unique probe forthe sea quark spin measurement.
PHENIX can detect W via the muon decay channel with the forward Muon Arm, which consists of theMuon Tracker (MuTr) and Muon IDentiﬁer (MuID).
The MuTr is a set of cathode strip chambers thatare used for momentum measurement with a magnetic
ﬁeld. The MuID is a set of ﬁve chamber layers withalternating layers of steel walls which can distinguishmuons from hadrons. The MuID also serves as a ﬁrstlevel muon trigger.
√
The RHIC design luminosity at s = 500 GeV is
2 × 1032 cm−2 s−1 . When this is achieved, the reaction
rate is 12 MHz. With the existing MuID trigger, whose
rejection factor (RF) is about 250, the trigger rate is
as high as 48 kHz. However, the maximum allowed
trigger rate is 2 kHz, so we need a new trigger with the
RF of at least 6 k to record all the W signals.
In MuID triggered events observed to date, lowmomentum muons dominate while most of themuons that decayed from W have momentum above
40 GeV/c. By selecting high-momentum muons at thetrigger level, the desired RF can be achieved. However,
the threshold of the MuID trigger is determined by theabsorber thickness of the MuID steel, thus it is not easy
to change the threshold. Therefore, we propose a new
trigger with existing MuTr to select high-momentum
muons. Figure 1 shows the concept of the new trigger.
A muon has its trajectory bent in a magnetic ﬁeld, thus
the distance between the straight interpolation and theactual track (which is called the sagitta) is larger if the∗

Department of Physics, Kyoto University

Fig. 1. The new trigger concept.

muon momentum is low. Thus, MuTr hit matching in
the trigger level can be used to select high-momentum
muons. This trigger also rejects unnecessary events inwhich muons are outside the MuTr acceptance but arein the MuID acceptance.
We performed simulations to estimate both the RF
and eﬃciency for the W signal of the proposed trigger.
The simulations were performed with the CCJ. Table 1 shows the estimated RF and eﬃciency. “∆str”
denotes a sagitta which is expressed in terms of thenumber of MuTr strips (= 10 mm). The eﬃciency of
66% is due to the acceptance (75%) and trigger planeeﬃciency (96%)3 . Suﬃcient RF is achieved while almost maximum eﬃciency is realized. Figure 2 shows
the trigger logic eﬃciency in terms of muon momentum(trigger plane eﬃciency is not included).
To realize this idea, we are developing the fast readout electronics for the MuTr so that hit infomation canbe used at the trigger level. We hope to ﬁnalize theﬁrst prototype soon.
Table 1. Estimated Rejection Factor and eﬃciency for W .
∆str is a sagitta in terms of the number of MuTr strips.
RFeﬀ.

MuID only
250
95∆str ≤ 1
24 k
66∆str ≤ 2
11 k66∆str ≤ 3
7k
66

Fig. 2. Trigger logic eﬃciency for muons in the acceptance.
Simulation.

References
1) K. Adcox et al.: Nucl. Istrum. Methods Phys. Res. A
499, 469 (2003).
2) J. Ashman et al.: Phys. Lett. B 206, 364 (1988).
3) G. Bunce et al.: Annu. Rev. Nucl. Part. Sci. 50, 525(2001).

219

RIKEN Accel. Prog. Rep. 38 (2005)

Multiparticle analysis for jet identification at PHENIX
K. Nakano∗ and Y. Goto
One of the goals of the PHENIX experiment is toobtain the polarized gluon distribution function in nucleon. With longitudinally polarized proton-proton
collisions at RHIC, particles produced with high transverse momentum (pT ) are measured. Until recently, we
have mainly focused on single-particle productions.1)
Here, we expand our scope and start analyses of multiple particles for the measurement of jet production.
We need detailed studies of better jet-identification
methods using the limited acceptance of the PHENIX
Central Arms which cannot detect all the particles
from a jet. The multiparticle measurement will provide
us with higher statistics in the high-pT region than the
single-particle measurements.
We used RHIC-PHENIX RUN3 polarized proton√
proton collision data, which was obtained at s =200 GeV with an average beam polarization of ∼ 26%.
For event selection, we required that at least one photon had a pT of > 2 GeV/c. There are two Central
Arms at PHENIX, each of which covers the pseudorapidity region |η| < 0.35 and 90-degree azimuthal angle, and are positioned almost back-to-back on theirazimuth. We 
measured the total transverse momen≡ | i pT i |, by summing pT of photons andtum, psumTcharged particles in one of the Central Arms which
involves photons with pT > 2 GeV/c. For 2 → 2
hard scattering events, we expect that one of thearms detects photons and charged particles from one
scattered parton, and we can evaluate pT and shapeof a jet. Photons were detected with electromagnetic calorimeters and identified with shower-shapeand charged-track veto conditions. Charged particles
were detected with drift chambers and pad chambers
and identified with a track-quality condition. Photons with pT > 0.4 GeV/c and charged particles with
0.4 GeV/c < pT < 5 GeV/c were used to calculate thetotal transverse momentum.
To study the structure of events detected in one arm,
we used a thrust variable, which represents the topology of particles. The thrust T is defined as
i |pi · u|.
(1)
T ≡ max ui |pi |
Here, u is a unit vector, which is called thrust axis andis directed to maximize T , and pi is the momentum ofeach particle in one arm. T is equal to one when all pi
are collinear, and T decreases as the jet cone size increases. In the PHENIX Central Arm acceptance, themean value of the thrust of high-multiplicity isotropic
events is equal to 0.88.
Figures 1 and 2 show the thrust distributions for∗220

Department of Physics, Tokyo Institute of Technology

Fig. 1. Thrust distribution (6 < psum
< 7 GeV/c).
T

Fig. 2. Thrust distribution (8 < psum
< 9 GeV/c).
T

events which have three particles in one arm and 6 <psum< 7 GeV/c and 8 < psum
< 9 GeV/c, respectively.
T
T
They are compared with high-pT QCD (hard scattering) events simulated with the PYTHIA event generator and isotropic events simulated by simply assumingthat the particle production cross section is proportional to exp(−pT ). We used PYTHIA with tuned
Multi-Parton Interaction (MPI) parameters because
it reproduces event structures better than with thedefault parameters.2,3) The measured thrust distributions show a rough agreement with the PYTHIA simulation, and this agreement indicates that the selected
events are dominated by hard scattering events. The
thrust values of both the real data and the PYTHIA
calculation are generally larger than those of isotropic
range, andcalculation, particularly in the high-psumTincreases.
the distributions become sharper as psum
T
This is a characteristic of the shape of the jet. Therefore, we can conclude that jet structures are observedwith the acceptance of the PHENIX Central Arms.
References
1) S. S. Adler et al.: Phys. Rev. Lett. 93, 202002 (2004).
2) T. Aﬀolder et al.: Phys. Rev. D 65, 092002 (2002).
3) R. Field: Acta Phys. Pol. B 36, 167 (2005).

RIKEN Accel. Prog. Rep. 38 (2005)√
Pentaquark search in sN N = 200 GeV Au+Au collisions
at RHIC-PHENIX
M. Kaneta and H. Torii, for the PHENIX Collaboration

The Relativistic Heavy Ion Collider (RHIC) at
Brookhaven National Laboratory is the largest heavyion collider and provides the highest energy heavy-ion
collisions in the world. There are two areas of research
at RHIC. The ﬁrst one is the Quark-Gluon Plasma(QGP) search and the other is investigating the originof the proton spin. The PHENIX experiment is one of
the largest experiments at RHIC. The important issue
in the QGP search is to measure several signals simultaneously. To accomplish that, PHENIX is designed
to measure photons, identiﬁed hadrons, electrons (atthe mid-rapidity region) and muons (at the forwardrapidity region).
The LEPS collaboration has reported an evidence
for a narrow S = +1 baryon resonance state.1) It isa candidate for Θ+ (uudds̄) of which existence is predicted with mass 1.540 GeV. Θ+ has two decay modes,
K + + n and K 0 + p. Additionally, the NA49 experiment at CERN-SPS has reported the other penta¯ 2)(ssddū) and Ξ03 (ssudd).
quark states, called Ξ−−
322
Since the antibaryon to baryon ratio is more than√
0.75 at mid-rapidity in sN N = 200 GeV p + p and
Au+Au collisions,3–6) we expect that antipentaquark
to pentaquark ratio is a similar to or larger than 0.75.
We have been attempting pentaquark searches using
antineutrons, that is, Θ̄− → K − + n̄. PHENIX hasan advantage in antineutron measurements with theElectro-Magnetic Calorimeter (EMCal). The K − + n̄
channel (two-body decay) has a larger acceptance thanthe KS0 + p(p̄) (which will decay three particles ﬁnally,i.e., π + + π − + p(p̄). Hence, K − + n̄ is a better channel
than KS0 + p(p̄) for the PHENIX measurement.
The main purpose of PHENIX EMCal is photon andelectron measurement. An antibaryon makes a larger
energy deposit and diﬀerent energy shower shape thanphotons and electrons. We identiﬁed an antineutron
requiring three conditions: (1) an energy deposit on
EMC is larger than 1 GeV, (2) the energy deposit notdue to charged particles, (3) the shower shape is different from those produced by photons and electrons.
K − is identiﬁed by a cut of combinations of momentum and the EMCal Time-of-Flight.
The data we used is a set of minimum bias trigger√
data in sN N = 200 GeV Au+Au collisions. The invariant mass distribution of the K − and n̄ pair is calculated for each event. The distribution has a combinatorial background and we estimate it by event mixing.
The event mixing is performed by combining similar
conditions of the event vertex and the centrality. The
background distribution obtained is normalized to thedata in a mass range of 1.6–1.8 GeV/c2 . Figure 1 shows

Fig. 1. Invariant mass distributions of K − and n̄ pairand combinatorial background distribution (solid histograms) are shown for each centrality bin. The plot
after background subtraction is shown on top-right ineach plot.

the invariant mass distribution of the K − and n̄ pairwith the background distribution (solid histogram) ineach centrality bin. The centrality range is shown ineach histogram.
The results show no signiﬁcant pentaquark peakaround the expected mass (∼ 1.540 GeV/c2 ) in any
centrality bin. The estimation of the upper limit is inprogress.
References
1) LEPS Collaboration, T. Nakano et al.: Phys. Rev. Lett.
91, 012002 (2003).
2) NA49 Collaboration, C. Alt et al.: Phys. Rev. Lett. 92,
042003 (2003).
3) BRAHMS Collaboration, I. G. Bearden et al.: nuclex/0409002.
4) PHENIX Collaboration, S. S. Adler et al.: Phys. Rev.
C 69, 034909 (2004).
5) PHOBOS Collaboration, B. B. Back et al.: nuclex/0409003.
6) STAR Collaboration, J. Adams et al.: Phys. Rev. Lett.
92, 112301 (2004).

221

RIKEN Accel. Prog. Rep. 38 (2005)

Pentaquark search in√sN N = 200 GeV p + p and d+Au collisions
at RHIC-PHENIX

H. Torii and M. Kaneta, for the PHENIX Collaboration
Since the ﬁrst experimental evidence of a narrow
S = +1 baryon (Θ+ ) was reported by T. Nakano
et al.,1) further lines of evidence of Θ have been published by other researchers.2) The mass of Θ+ is close
to the theoretical value predicted using a quark-soliton
model3) as the ground state of antidecuplet baryon.
According to the model, Θ is predicted to conﬁne
ﬁve quarks (ududs̄) unlike three quarks. In addition
to the ground state, the model predicts a higher excited state (Ξ3/2 ), whose candidates were observed by
NA49 collaboration.4) The obtained evidence for the+
ground√ state Θ is either from low-energy experiments
at s < 10 GeV or from a photoproduction process.
However, no positive evidence of Θ+ has been found5)
in hadron collisions at a high energy.
Here, we report on the search for Θ̄− at RHIC√
PHENIX in sN N = 200 GeV p + p and d+Au collisions obtained during 2002–2003. The numbers ofevents analyzed for p + p and d+Au collisions are 35M
and 91M, respectively.
The PHENIX experiment6) has the advantage of being able to search the anti-pentaquark state throughthe Θ̄− → n̄ + K − channel rather than Θ̄+ → p + Ks0 .
To identify n̄, we used the PHENIX electromagnetic
calorimeters (EMCal), which have an azimuthal coverage of 90◦ + 90◦ and a pseudorapidity coverage of±0.35. Because of the ﬁne segmented structure andannihilation process of baryon and anti-baryon, EMCal can identify n̄. For each cluster detected by EMCal, we require 1) a deposited energy of more than
1 GeV, 2) the absence of a charged particle near the
candidate, and 3) larger shower size than photon.
The charged particles of π ± and K ± are identiﬁed
from the time-of-ﬂight measured by EMCal. As proof
that n̄ is well identiﬁed, we utilize a decay process ofΣ̄± → n̄ + π ± . Figure 1 shows the invariant mass
spectra of n̄ + π ± with clear peaks at approximately
1.2 GeV. The shaded area represents an expected contribution of combinatorial background. In the n̄ + π +distribution, a deviation from the background at mass
region lower than the peak position can be explainedby the background process of Λ̄ → p̄ + π + . The two
peak positions are consistent with expectations fromthe known masses of Σ± .2) The diﬀerence between thetwo peak positions is explained by the diﬀerence in thenominal mass.
Figure 2 shows the invariant mass spectra of n̄ + K −in p + p and d+Au collisions with the expected background distribution depicted as a shaded area. The
average mass2) of Θ+ observed by other experiments
is indicated by the arrow in the ﬁgure. No clear peaks

222

Fig. 1. Invariant mass spectra of n̄ + π ± . The shaded areashows the expected contribution of the background.
The positions of the peaks are consistent with those
expected from the decay of Σ̄± .

Fig. 2. Invariant mass spectra of n̄ + K − in p + p andd+Au collisions. The shaded area shows the estimatedbackground. The arrows represent the expected massof the pentaquark.

at the expected region are observed. The estimate of
the upper limit of the production cross section is inprogress.
References
1) LEPS Collaboration, T. Nakano et al.: Phys. Rev. Lett.
91, 012002 (2003).
2) For a recent review, Particle Data Group Collaboration,
S. Eidelman et al.: Phys. Lett. B 592, 1 (2004).
3) D. Diakonov et al.: Z. Phys. Lett. A 359, 305 (1997).
4) NA49 Collaboration, C. Alt et al.: Phys. Rev. Lett. 92,
042003 (2003).
5) See references in HyperCP Collaboration, M. J. Longoet al.: hep-ex/0410027.
6) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).

RIKEN Accel. Prog. Rep. 38 (2005)√
Measurement of single electrons in sN N = 62.4 GeV Au-Au
collisions at RHIC PHENIX

T. Tabaru, Y. Akiba, R. Averbeck,∗1 S. Butsyk,∗1 F. Kajihara,∗2 M. Togawa,∗3 and Y. Tsuchimoto,∗4
for the PHENIX Collaboration
There is growing evidence that a new hot and/or
dense matter is formed in heavy ion collisions at the
RHIC energy. This state is considered to consist of
deconﬁned partons. Heavy quarks are produced in theearly stage of collisions, mainly from hard gluon-gluon
fusions, and travel through the matter consisting ofpartons. Consequently, their yields are sensitive to theinitial gluon density.1) In addition, the heavy quarks
experience interactions with the medium in a way different from light quarks, due to their heavy mass,2)
providing important information on the nature of thematter created at the RHIC energy.
In high-energy nuclear collisions, a large portionof electrons with transverse momentum (pT ) larger
than 1 GeV/c comes from the decays of open heavy
quarks (charm and bottom). Therefore, one can measure heavy quark production via electrons. This measurement also provides the baseline for the analysis of the J/ψ meson, which is predicted to be either suppressed3) or enhanced4) in the presence of deconﬁned quarks and gluons. In the RHIC-PHENIX
experiment,5) we measured electrons at mid-rapidity(|η| < 0.35) in the pT range of 0.5 to 5 GeV/c in Au√
Au, d-Au and p-p collisions at sN N = 200 GeV, and√in Au-Au collisions at sN N = 62.4 GeV. In this arti√cle, we focus on the new data at sN N = 62.4 GeV.
During the 2004 run period, we recorded 2.6 × 107√
events of Au-Au collisions at sN N = 62.4 GeV withthe minimum bias trigger, which was deﬁned as a coincidence of two beam-beam counters. The paths of thecharged particles were reconstructed with drift chambers and pad chambers. The electrons were identiﬁed by Ring Imaging Čerenkov counters (RICH) andelectromagnetic calorimeters. We evaluated a large
background of electrons from γ-conversion and from
Dalitz decays of π 0 and η mesons using “converter
subtraction method” as described in the literature.6)
For this purpose, we performed a dedicated run withadditional conversion material (converter run) and collected 2.1 × 106 events. After subtracting the Dalitz
and conversion backgrounds, there remained small
backgrounds from kaon decays and light vector meson decays. These remaining background components
were estimated using a Monte Carlo simulation. We
found that the yield of these two components was ap-

∗1
∗2
∗3
∗4

proximately 10% of electrons form π 0 Dalitz decays in
the range of pT > 1 GeV/c.
Subtracting all backgrounds, the only remaining
source of electrons is heavy quark decays. Figure 1
shows the fully corrected electron spectrum from heavy
quark decays. In the ﬁgure, the ISR single electron data7–9) are also plotted after being scaled using the number of binary nucleon collisions for comparison. There is no signiﬁcant diﬀerence between
these data, which means that heavy quark production
scales with the number of binary collisions. This isalso consistent with the result of the Au-Au data at√
sN N = 200 GeV.6)

Fig. 1. Comparison of single electron pT spectra between√
present data and the ISR data taken at same sN N .

References
1) B. Muller and X. N. Wang: Phys. Rev. Lett. 68, 2437
(1992).
2) Y. L. Dokshitzer and D. E. Kharzeev: Phys. Lett. B
519, 199 (2001).
3) T. Matsui and H. Satz: Phys. Lett. B 178, 416 (1986).
4) R. L. Thews, M. Schroedter, and J. Rafelski: Phys. Rev.
C 63, 054905 (2001).
5) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
6) S. S. Adler et al.: nucl-ex/0409028.
7) F. W. Büsser et al.: Nucl. Phys. B 113, 189 (1976).
8) P. Perez et al.: Phys. Lett. B 112, 260 (1982).
9) M. Basile et al.: Nouvo Cimento A 65, 421 (1981).

Stony Brook University, State University of New York, USA
Center for Nuclear Study, University of Tokyo
Kyoto University
Hiroshima University

223

RIKEN Accel. Prog. Rep. 38 (2005)

Measurement of analyzing power in pp elastic scattering in peak CNI
region with polarized hydrogen gas jet target
H. Okada,∗1 I. Alekseev,∗2 A. Bravar,∗3 G. Bunce,∗3 S. Dhawan,∗4 R. Gill,∗3 W. Haeberli,∗5 O. Jinnouchi,
A. Khodinov,∗3 A. Kponou,∗3 K. Kurita,∗6 Z. Li,∗3 Y. Makdisi,∗3 A. Nass,∗3 S. Rescia,∗3 N. Saito,∗1
H. Spinka,∗7 E. Stephenson,∗8 D. Svirida,∗2 T. Wise,∗5 and A. Zelenski∗2
The elastic scattering of nucleons has been studied
for a long time as the most fundamental informationon the reaction of the elementary building blocks ofthe matter, nucleons. Five independent helicity amplitudes (φi ; i = 1∼5) are required to describe thisprocess, assuming parity conservation. For example,
the total cross section is described with φ1 and φ3 .
For spin-dependent asymmetry, analyzing power (AN )is expressed with φ5 , which represents the hadronic
spin ﬂip amplitude. Particularly in very small momentum transfer in the −t range of 0.001–0.02 (GeV/c)2 ,the helicity amplitudes of hadronic and electromagnetic components become similar and interfere witheach other. AN is expected to reach ∼4.5% at −t of∼0.003 (GeV/c)2 and is expected to change dynamically. We call this phenomenon Coulomb Nuclear Interference (CNI), and the shape of AN is related to thehadronic amplitude.1) The only AN data in the CNI
region is from E704 at Fermilab, but the accuracy islimited to see the peak structure of AN .
The CNI process is ideal in applications to a polarimeter for a high-energy proton beam, and to determine the RHIC beam polarization,2) we installed
the RHIC Absolute Polarimeter this spring.3) The polarimeter comprises a polarized hydrogen gas jet target which includes a Breit-Rabi polarimeter to obtaina precise absolute measurement of the target polarization4,5) and a silicon spectrometer which counts theelastic scattering event yield. Both beam and target
are protons; precise measurements of absolute beampolarization and AN are completed simultaneously.
Figure 1 shows the schematic of the setup. To reduce
systematic errors, the target polarization was ﬂipped(up and down) every 8 minutes. We measured theenergy (TR ), time of ﬂight (tof ) and angle (θR ) of therecoil particles using silicon detectors, as shown.
To determine AN , we count the elastic event yields
from the left (Nleft ) and right (Nright ) detectors, anddivide their diﬀerence-to-sum ratio by the target polarization.
AN =
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8

224

Fig. 1. Setup.

The key features of this experiment are high and accurate target polarization and correct selection of theelastic events. The target polarization was considerably high, accurate (0.924 ± 0.018)4) and stable during
the entire running time. For the correct selection ofelastic events, we conﬁrmed that both recoil particle
mass and forward-scattered particle mass were consistent with those of the proton, using two correlations.
The correlation of TR and tof conﬁrms that the recoil
particle is a proton (see Fig. 2). The correlation of
TR and θR conﬁrms that the forward-scattered particle is a proton (see Fig. 3). In Fig. 3, TR decreases atrecoil angles of more than 5 mrad because the recoil
protons penetrated through the silicon detector. To
avoid this eﬀect, we have focused on a smaller TR region, TR < 5 MeV, which corresponds to the −t regionof 0.0015–0.01 (GeV/c)2 .
In this manner, we selected the elastic events correctly and counted event yield asymmetry. We obtained then ﬁnally AN . Figure 4 shows our results asblack points and E704 data as open circles. The errors on the y-axis are statistical only. The systematic
errors of our data points are 0.0015 for all bins.
We measured AN in the peak CNI region for theﬁrst time. The asymmetry is large and consistent withthat without hadronic spin-ﬂip (Fig. 4). However, the1 Nleft − Nright
Ptarget Nleft + Nright

Department of Physics, Kyoto University
Institute for Theoretical and Experimental Physics, Russia
Brookhaven National Laboratory, USA
Yale University, USA
Department of Physics, University of Wisconsin, USA
Rikkyo University
Argonne National Laboratory, USA
Indiana University Cyclotron Facility, USA

Fig. 2. Correlation of TR
and tof.

Fig. 3. Correlation of TRand θR .

sensitivity to the hadronic spin ﬂip is higher for |t| >0.01. Further analysis is in progress.
References

Fig. 4. AN data for pp elastic scattering as a function of −t.
Black circles depict our data obtained this spring andopen circles depict E704 data. The solid line is fittedwith nonhadronic spin flip. The analysis is in progressin the region marked by the arrow.

1) L. Trueman: Proc. 16th Int. Spin Physics Symp. (SPIN
2004), Torieste, Italy, 2004-10 (To be published).
2) O. Jinnouchi et al.: RIKEN Accel. Prog. Rep. 37, 245(2004).
3) H. Okada et al.: RIKEN Accel. Prog. Rep. 37, 243(2004).
4) A. Zelenski: Nucl. Instrum. Methods Phys. Res. A 536,
248 (2005).
5) A. Nass et al.: Proc. 16th Int. Spin Physics Symp.
(SPIN 2004), Torieste, Italy, 2004-10 (To be published).

225

RIKEN Accel. Prog. Rep. 38 (2005)

Measurement of the analyzing power of proton-carbon elastic
scattering in the CNI region at RHIC
O. Jinnouchi, I. G. Alekseev,∗1 A. Bravar,∗2 G. Bunce,∗2 S. Dhawan,∗3 R. Gill,∗2 H. Huang,∗2 W. Haeberli,∗4
G. Igo,∗5 V. P. Kanavets,∗1 K. Kurita,∗6 A. Khodinov,∗7 Z. Li,∗2 Y. Makdisi,∗2 A. Nass,∗2 W. Lozowski,∗8
W. W. Mackay,∗2 H. Okada,∗9 S. Rescia,∗2 T. Roser,∗2 N. Saito,∗9 H. Spinka,∗10 D. N. Svirida,∗1
D. Underwood,∗10 C. Whitten,∗5 T. Wise,∗4 J. Wood,∗5 and A. Zelenski∗2
The proton-carbon elastic scattering process in the
Coulomb Nuclear Interference (CNI) region of very
low momentum transfer, −t, has been used for thepolarization measurment of the relativistic heavy-ion
collider (RHIC) proton beam. This polarimeter has
proven to be reliable, and has a high performance inmeasuring the beam polarization. In addition, thesystematic errors, which were detailed in the annual
reports,1–3) are now mostly understood from the recent years of running. In spite of these advantages,
the absolute normalization, i.e., the analyzing power(AN ) of the process, has been known with 30% uncertainty4) only near the RHIC injection energy (24 GeV).
During the run 2004, data were collected simultaneously with the Polarized Hydrogen Jet target, whichmeasure the beam polarization5) for calibrating the pcarbon process at 24 and 100 GeV. The carbon ionsrecoil from the ultrathin carbon target and are detected by the silicon strip detectors (SSDs). The invariant mass is reconstructed with the measured timeof ﬂight and kinetic energy of carbon. The carbon
mass peak (σ = 1.7 GeV/c2 ) is clearly distinguishedfrom background, and the carbon events are deﬁned
as the events within 3 standard deviations. The asymmetry is calculated with the square-root formula6) totake full advantage of the alternating spin pattern in
RHIC. The details of the setup and DAQ system aredescribed in the previous article.7) −t is approximatedas −t = 2 × MC Ekin , where MC is the carbon massand Ekin is the recoil energy; thus energy measurement is essential to precisely determine −t. For theenergy calibration, the signal of 5.486 MeV α-particles
from the 241 Am source is monitored throughout therun. Although SSDs were manufactured to have avery thin nonactive surface, the energy loss in this surface layer has a signiﬁcant eﬀect on low-energy spectroscopy. The layer thickness is assessed from the deformation of the carbon kinetic curve (tof vs. energy
correlation). The thickness of 57 µg/cm2 is obtainedwith the uncertainty of ±12 µg/cm2 , which is the ma∗1

Institute for Theoretical and Experimental Physics, Russia
Brookhaven National Laboratory, USA∗3 Yale University, USA∗4 University of Wisconsin, USA∗5 University of California, Los Angeles, USA∗6 Rikkyo University∗7 Stony Brook University, USA∗8 Indiana University Cyclotron Facility, USA∗9 Kyoto University∗10 Argonne National Laboratory, USA∗2

226

jor systematic error of this measurement. 1.2×109 carbon events were collected with the Jet polarimeter running in parallel. Figure 1 shows the obtained ApC
N (t)at 100 GeV. The thin line on top of the data points
is the ﬁtting result with the model function which allows hadronic spin ﬂip.8) The error bars on data points
represent the quadratic sum of the statistical error andthe systematic error from the cut dependence on the invariant mass of carbon. Other major systematic errors
are due to (i) the −t ambiguity from the uncertainty ininactive surface layer thickness, and (ii) the error of thebeam polarization measured with the Jet polarimeter,
and these are shown by the shaded band in the ﬁgure. The major goal (δP/P < 10% calibration) of the
Run-04 commissioning was successfully achieved. The
AN (t) of the pC polarimeter at 100 GeV is obtainedwith good precision. The data at 24 GeV are underanalysis, and we are looking forward to obtaining the
new 24 GeV result fairly soon.

Fig. 1. Measured ApC
N (t) at RHIC 100 GeV. The calibration is carried out with jet measurement. The best-fit
result obtained using hadronic spin-flip model significantly departs from the result of the non-spin-flip calculation (top curve). The shaded band represents thesystematic uncertainty of the measurement.

References
1) O. Jinnouchi et al.: RIKEN Accel. Prog. Rep. 35, 228(2002).
2) O. Jinnouchi et al.: RIKEN Accel. Prog. Rep. 36, 237(2003).
3) O. Jinnouchi et al.: RIKEN Accel. Prog. Rep. 37, 245(2004).
4) J. Tojo et al.: Phys. Rev. Lett. 89, 052302 (2002).
5) H. Okada et al.: RIKEN Accel. Prog. Rep. 38, 224(2005).
6) G. G. Ohlsen and P. W. Keaton: Nucl. Instrum. Methods 109, 41 (1973).
7) O. Jinnouchi et al.: AIP Conf. Proc. 675, 817 (2003).
8) T. L. Trueman: hep-ph/0305085 (2003).

RIKEN Accel. Prog. Rep. 38 (2005)

PHENIX silicon vertex detector upgrade projectY. Akiba, J. Asai, H. En’yo, K. Fujiwara,∗1 Y. Goto, J. M. Heuser, H. Kano, T. Kawasaki,∗1 Z. Li,∗2
H. Ohnishi, V. L. Rykov, N. Saito,∗3 T. Tabaru, A. Taketani, M. Tanaka,∗4 M. Togawa,∗3 J. Tojo,
Y. Watanabe, and PHENIX VTX Collaboration
We propose the construction of a silicon vertex
tracker (VTX) for the PHENIX experiment at RHIC.
The VTX will substantially enhance the physics capabilities of the PHENIX central arm spectrometer. Our
primary aim is to enable the precision measurements ofheavy-quark production (charm and beauty) in A + A,
p(d) + A, and polarized p + p collisions. These are key
measurements that are required for the future RHIC
program, both for the study of high-density partonic
matter created in heavy ion collisions and for the exploration of the nucleon spin structure function.
The main physics topics addressed by the VTX are
as follows.
• Probing high-density partonic matter◦ open charm production◦ open beauty production◦ energy loss of charm in the dense matter◦ Thermal dilepton radiation• Gluon spin structure of nucleon◦ ∆G/G measurement with charm◦ ∆G/G measurement with beauty◦ ∆G/G with γ-jet measurement• Nucleon structure in nuclei◦ Gluon shadowing over broad x-range
The proposed VTX detector is shown in Fig. 1. The
detector consists of two layers of silicon pixel detectors
at the radii of 2.5 cm and 5 cm from the beam pipe
and two layers of silicon strip detectors at the radii of
10 and 14 cm. The silicon pixel detector1,2) has beenFig. 1. The PHENIX VTX detector.
∗1
∗2
∗3
∗4

Niigata University
Brookhaven National Laboratory, USA
Kyoto University
High Energy Accelerator Research Organization (KEK)

developed in collaboration with the ALICE group at
CERN (RIKEN–ALICE collaboration). The PHENIX
pixel sensor and read-out chip are based on those of
ALICE. The pixel chips were used andworked very wellin the NA60 experiment. The silicon strip detector
uses a novel “stripixel” sensor developed at BNL.3) The
sensor is to be read out using the SVX4 chip developed
at FNAL.
The main points of progress in this year are as follows.
• The conﬁguration of the detector is upgraded totwo pixel and two strip layers. The new conﬁguration enables much more robust vertex tracking
as well as better stand-alone momentum measurement.
• QA of the pixel chips at CERN4)• Development of “pilot” ASIC for the pixel layers5)• Development of thin data bus for the pixel layers6)• Development of the strip sensor7)• QA of the strip sensors at BNL8)• R&D of the strip ROCs using SVX4 chip at ORNL
• Software development for VTX9)With the aim of gaining the approval of the PHENIX
silicon upgrade project as a construction plan, the“Proposal for a Silicon Vertex Tracker (VTX) for the
PHENIX Experiment” was submitted to the U.S. Department of Energy through BNL in August 2004.10)
References
1) H. Ohnishi et al.: RIKEN Accel. Prog. Rep. 38, 230(2005).
2) J. M. Heuser et al.: RIKEN Accel. Prog. Rep. 38, 139(2005).
3) Z. Li et al.: Nucl. Instrum. Methods Phy. Res. A 518,
300 (2004)
4) K. Fujiwara et al.: RIKEN Accel. Prog. Rep. 38, 228(2005).
5) H. Kano et al.: RIKEN Accel. Prog. Rep. 38, 237(2005).
6) A. Taketani et al.: RIKEN Accel. Prog. Rep. 38, 233(2005).
7) J. Tojo et al.: RIKEN Accel. Prog. Rep. 38, 231(2005).
8) J. Asai et al.: RIKEN Accel. Prog. Rep. 38, 235(2005).
9) V. L. Rykov et al.: RIKEN Accel. Prog. Rep. 38, 236(2005).
10) Y. Akiba et al.: Proposal for a Silicon Vertex Tracker(VTX) for the PHENIX Experiment (BNL, Upton,
NY, 2004).

227

RIKEN Accel. Prog. Rep. 38 (2005)

Evaluation of pixel read outchip of PHENIX silicon vertex upgrade
K. Fujiwara∗ , J. M. Heuser, H. En’yo, T. Iwabuti∗ , H. Kano, T. Kawasaki∗ , H. Ohnishi, and A. Taketani
The PHENIX experiment at the Brookhaven National Laboratory has been running since the year
2000, and it is planned to be upgraded by the year
2007 to enhance its physical capability in both heavy
ion collisions (Au-Au) and polarized proton-proton collisions at the Relativistic Heavy Ion Collider. The purpose of the upgrade is to enable the precise measurement of heavy quarks, which carry direct signals from a
Quark Gluon Plasma in heavy ion collisions and fundamental information of gluon polarizartion in polarized
proton-proton collisions. Thus, the RIKEN group isdeveloping a novel Silicon Pixel Detector (SPD) with
the ALICE collaboration at CERN. A vertex tracker
is planned with four cylindrical layers surroundinga beam pipe and each layer is placed 2.5 cm, 5 cm,
8 cm and 10 cm from the collision point, such that the
tracker is exposed to very high radiation during theexperiment period because of the high particle multiplicity. The inner two layers are constituted by an SPD
and the outer two layers are constituted by a Silicon
Strip Detector. The inner two layers are installed ina particularly high radiation environment. Therefore,
we decided to construct these devices with radiation
hardness technology, which was developed by the ALICE group at the CERN Large Hadron Collider.1)
This device is a hybrid device consisting of a silicon
pixel sensor and a readout chip, which are interconnected by bump bonding technology with microscopic
solder balls. The sensor chip is based on 200-µmthick P+ N silicon produced by CANBERA and has 32
columns × 256 rows of pixels of 425 µm (z) × 50 µm(φ) size; the total size of the readout chip is 15.5 ×
13.6 mm2 . The ALICE1LHCb readout chip is designed
using a commercial 0.25 µm radiation hardness process, functions as an ampliﬁer of a raw signal from eachpixel, discriminates with conﬁgurable threshold levels,and stores this discriminated binary information to beread out downstream by a data acquisition system.
The chip has 42 internal 8 bit Digital-to-Analog Converters (DACs) for controling the threshold of discriminators and various timings.2) All conﬁgurations are set
via the JTAG serial interface (IEEE std. 1149.1-1990).
The chip can be operated with a 10 MHz clock; therefore, the readout speed can be 25.6 µsec/chip with a
32 bit line.
Four hundred eighty ALICE1LHCb readout chips
are required for the construction of the PHENIX Silicon Vertex Tracker. They are produced using a special
method, which is radiation tolerance technology, as 8
silicon wafers. In addition, the yield rate of the readout chips is not always 100%; therefore, it is necessary∗

228

Science and Technology, Niigata University

to probe the chip on the wafer. To identify fully functional chips, we have two tests which are carried out
before and after bump bonding. They were developedat CERN.3) One is a quality assurance (QA) test of the
ALICE1LHCb readout chip on a wafer. The other isthe QA test of interconnected hybrid ladders with a radioactive source to check the interconnection of boththe sensor substrate and readout chips. This report
describes the ﬁrst QA test. Each procedure is performed using a semiautomatic probe station at CERN,
which is shown in Fig. 1. One wafer contains 86 readout chips. In the ﬁrst test, all chips are touched witha dedicated probe card and connected to the testing
equipment. Then, test pulses and control signals are
injected into the chip and digital information is readout for evaluation. Initially, all chips are tested for thefollowing common parameters.
• Measurement– Both digital and analog current consumptions
are measured.
• Conﬁrmation– JTAG functionality.
– The internal DAC functionality is tested. In
the test, the linearlity of the changed DAC
value is measured.
– The minimum threshold and noise level on achip are measured. Initially, a global threshold on a chip is set. Then, the reference pulse
is sent to each pixel as the pulse height ischanged. The minimum threshold is deﬁned
as the dispersion from the global level for all
pixels and also the minimum noise level is deﬁned as the dispersion of each pixel threshold.

Fig. 1. Semiautomatic prober.

The classiﬁcation of the wafer probe is divided into
three classes (Classes 1, 2, 3), which is described later.
Class 1 chips are of suﬃciently good quality for theconstruction of a ladder. Chips that have more than 82
defect pixels or that have a minimum threshold higher
than 30 mV (1980 e− ) become Class 2. Finally, chipsthat have too much current for the digital or analog
circuit or that do not respond to the test pulse are put
into Class 3.
• Class 1 (Chips for ladder)– JTAG and DAC are functional.
– The consumption current for the analog circuit is less than 350 mA.
– The consumption current for the digital circuit is less than 270 mA.
– Less than 82 defect pixels on a chip.
– The minimum threshold is less than 30 mV(1980 e− ).
At present, 860 chips (10 wafers) have been probed,
and we have obtained 303 Class 1 chips. The average
yield is shown in Table 1. The average yield is 35% forClass 1 chips.
Figure 2 shows a typical minimum threshold andmean noise value. The minimum threshold is 1868 e− ,the standard deviation is 350 e− , and the mean noise
value is 205 e− . Usually, the number of electrons induced by the minimum ionizing particles in the siliconsensor of the thickness of 200 µm is around 15000 e− .
Consequently, the signal-to-noise ratio is more than
10. Figure 3 shows an example of the probing result.
It seems that Class 1 chips are in the middle region ofa wafer.
In summary, 303 Class 1 chips were obtained. Twoprobed wafers have already been sent to a factory forthe bump bonding process. The number of chips is sufﬁcient for the production of 75 ladders for the PHENIX
experiment, indicating that we can construct most of

Fig. 2. Typical minimum threshold dispersion and minimum noise dispersion on a readout chip (Wafer Name:
AVA4LJT, Chip ID: 6).

Fig. 3. Example of probing result.

the inner tracker with these chips. The tracker requires
480 chips and some spares; we expect to ﬁnish probing by the end of December 2004. The ﬁrst production ladders for PHENIX will arrive from the factory in
Jannuary 2005, and we will start probing these ladders
soon after.

Table 1. The total yield rate of wafer probing.

References
Class 1
Class 2
Class 3

35%
13%
52%

303 chips
108 chips
449 chips

1) Y. Akiba: RIKEN Accel. Prog. Rep. 38, 227 (2005).
2) J. M. Heuser: RIKEN Accel. Prog. Rep. 38, 139 (2005).
3) P. Riedler et al.: Nucl. Phys. A 501, 111 (2003).

229

RIKEN Accel. Prog. Rep. 38 (2005)

Development of silicon pixel detectors for PHENIX at CERN
H. Ohnishi, H. En’yo, K. Fujiwara, J. M. Heuser, H. Kano, and A. Taketani
The Silicon Vertex Tracker (SiVTX) has been proposed as a detector upgrade for the PHENIX experiment at the Brookhaven National Laboratory’s Relativistic Heavy Ion Collider. The prime motivation
for this new detector system is to provide precision
measurements of heavy-quark production (charm andbeauty) in A-A, p(d)-A, and polarized p-p collisions.
For these measurements, the new detector needs tosatisfy the following requirements:• The SiVTX needs to operate over a wide dynamic range, from particle multiplicities with a
few tracks in the case of p-p collisions up to several hundred tracks in central heavy-ion collisions.
• The origin of an electron from a heavy-quark decay has an oﬀset of the order of 100 µm with respect to the primary vertex position, due to thelife time of the heavy quark. In order to separate the electron from the background that mainly
originates from the primary vertex, the resolutionof the track oﬀset measurement must be equal toor less than 50 µm.
The SiVTX realizes the desired performance withfour layers of silicon detectors. It will consist of two
internal layers of silicon pixel detectors and two outerlayers of silicon strip-pixel detectors. For the pixel detectors, we decided to utilize the technology developed
for the ALICE experiment at the Large Hadron Collider (LHC) at CERN. Two activities are ongoing at
CERN for the PHENIX pixel detector project. Firstly,
we have established a collaboration with the ALICE
experiment, with the goal of actually constructing important componets for PHENIX silicon pixel detector
modules1) in a partnership with the ALICE Pixel Detector Group. Secondly, we are working with the NA60
experiment at the CERN-SPS which applies the same
silicon pixel detectors in its Vertex Tracker. The purpose of this collaboration is to learn the operation andbasic functionality of the silicon pixel detectors.
A more detailed description of the NA60 Vertex
Tracker is given elsewhere.2) The Vertex Tracker wasconstructed and installed in 2003 and operated during
two beam periods: Indium-Indium collisions in 2003
and proton-nucleus collisions in 2004. One of the challenges of this experiment is the operation of the silicon
pixel detector in a high-radiation environment. The
particle ﬂuence at the silicon pixel detector, which isvery inhomogeneous with radius from the beam axis,
is up to 1012 1 MeV equivalent neutron ﬂax per cm per
week (1 MeV neq. /cm2 /week). It should be noted thatthe radiation dose expected for the silicon pixel detector of ALICE is much lower, approximately 1.75 × 1012

230

1 MeV neq. /cm2 /10 y. The conditions for PHENIX are
similar. Therefore, ﬁve weeks of NA60 data taking corresponds to approximately 30 years of data taking with
ALICE or PHENIX. The measurements performed
with NA60 will be unique reference for determining thedetector performance, particularly concerning the radiation damage of the silicon sensors. The performanceof the detector was closely monitored during the run.
Figure 1 shows an example of the tests performed with
one of the tracking planes. The left panel presents an
integrated hit map obtained with the sensors biased at
150 V after ﬁve weeks of irradiation. The right panel
shows the situation at 30 V bias. Note that new sensors deplete typically between 9 V and 30 V bias. The
dead area in the central region of the plane indicatesthat at 30 V the silicon sensors were no longer fully
depleted; radiation damage and type inversion had occured where the sensors were exposed to the largest
particle ﬂuences. Further analysis of the systematic
measurements is ongoing and will give us a unique viewof the evolution of the radiation damage.
In summary, the silicon pixel detectors that we plan
to use for the PHENIX Vertex Tracker have beensuccessfully operated in a high-radiation environment.
In ﬁve weeks, the detectors sustained ﬂuences up to
5 × 1012 1 MeV neq. /cm2 , which is equivalent to three
decades of PHENIX running. These results justify theselection of the pixel detector for PHENIX in terms ofradiation hardness.

Fig. 1. Hit maps of an irradiated NA60 Pixel Detector
tracking plane at diﬀerent bias voltages. At low bias
voltage, the central area with reduced hits identiﬁes
type-inverted silicon.

References
1) J. M. Heuser et al.: RIKEN Accel. Prog. Rep. 38, 139(2005).
2) H. Ohnishi et al.: Nucl. Phys. A 734, 49 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Development of silicon stripixel detector for
PHENIX silicon vertex tracker
J. Tojo, Y. Akiba, J. Asai, H. En’yo, Y. Goto, Z. Li,∗ and A. Taketani
The use of a silicon vertex tracker (VTX) for the
PHENIX experiment in the Brookhaven National Laboratory (BNL) has been proposed to enhance thephysics capability of the baseline detector system.1)
The VTX consists of four barrel layers of silicon detectors that cover the acceptance of almost 2 π in an
azimuthal angle and |η| < 1.2 in pseudo-rapidity. An
overview of the PHENIX VTX project is given in
Ref. 2. In this article, we report the development of a
stripixel detector for the outer two barrel layers of the
VTX.
The stripixel detector concept innovated by the BNL
Instrumentation Division has a novel feature of twodimensional position sensitivity with single-sided processing, which is achieved by charge sharing between
two interleaved electrodes in one pixel. The details of
the detector concept are given in Ref. 3. The stripixel detector for the PHENIX experiment has been designed and prototyped in collaboration with the BNL
Instrumentation Division. The detailed performanceof the prototype detector has been studied in static
electrical tests4) and beam/source tests.5) On the basis of the results obtained, we decided to apply the
stripixel detector technology to the outer barrel layersof the VTX.
The outer two barrel layers of the VTX are planned
to be constructed with 246 stripixel sensors that covera 2000 cm2 area in the third layer and a 3400 cm2 areain the fourth layer.6) The production of such a large
number of silicon sensors has to be performed in a company that has an appropriate silicon wafer processing technology with an acceptable production yield.
The processing technology of the very ﬁne pattern andmany through holes in the stripixel sensor is nontrivial.
Two companies, SINTEF in Norway and Hamamatsu
in Japan, were selected as candidate companies for sensor mass production. In these two companies, sensor
preproduction has been carried out in order to evaluate the mass production capability of the company
technologies.
The sensor preproduction processes carried out aresummarized in Table 1. There are ﬁve types of preproduction sensor, distinguished in terms of the company
process, wafer mask design, wafer size and wafer thickness. The main diﬀerence between the SINTEF and
Hamamatsu processes is in the double-metal process
required to form strip electrodes in the stripixel sensor. The insulation layer between two metal layers ismade of 2-µm-thick polyimide in the SINTEF process
or 1-µm-thick SiO2 in the Hamamatsu process. Threemask designs in Table 1 were produced to meet theprocess and detector design requirements. In all thedesigns, the stripixel structure was designed with ﬁveturn spiral p+ electrodes of 5 µm lines and 3 µm gaps.
The “v2b” mask design is the same as the prototype
sensor design4) with two sensors on a 4 silicon wafer.
The “v2c” mask design is the same as the prototype
sensor design except for the guard ring and additional
aluminum pads for testing, with three sensors on a 6
silicon wafer. The “v3a” mask design was modiﬁed
from the v2c design to be optimum for the construction of a ladder-shaped detector module in the VTX.
The sensor design is shown in Fig. 1. The readoutpads were placed in the longer edges of the sensor anddesigned to match the SVX4 readout chip7) for use in
the VTX. The dead space in the middle of the sensor,
which existed in the v2c design for the arrangement of
the readout pads, was eliminated. A photograph of the“H-3a-500” type wafer is shown in Fig. 2. The numberof wafers processed and delivered is listed in Table 1.
In the ﬁrst stage of the evaluation, the fabricatedpreproduction sensors will be tested in a newly built
clean room at the RIKEN BNL Research Center andin the silicon detector facility at the University of New
Mexico.8) The static electrical properties (leakage current and capacitance) and the wafer/sensor production yield in each type of sensor will be measured on awafer with a semiautomatic probe station. The tested
wafers will be laser-diced at the BNL Instrumentation
Division. In the second stage, the sensors will be wirebonded to the readout electronics with SVX4 chips at
RIKEN and evaluated by reading out signals with theTable 1. Stripixel sensor preproduction processes.
Type
S-2b-500
H-2c-500
H-2c-625
H-3a-500
H-3a-625∗

Process
SINTEF
Hamamatsu
Hamamatsu
Hamamatsu
Hamamatsu

Mask design
v2b
v2c
v2c
v3a
v3a

Wafer size [in.]
4
6
6
6
6

Wafer thickness [µm]
500
500
625
500
625

# Wafer
17
6
6
11
12

# Sensor
34
18
18
33
36

Brookhaven National Laboratory, USA

231

Fig. 2. Photograph of the silicon stripixel sensor wafer.
The wafer type is H-3a-500 in Table 1.

injected nanosecond pulsed laser lights. On the basisof the results of the evaluation, the processing company for the stripixel sensor mass production will be
determined.
References

Fig. 1. (a) Layout of the v3a mask design sensor, (b) enlarged view of the square area in (a), and (c) enlarged
view of the square area in (b).

2321) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
2) J. M. Heuser: Nucl. Instrum. Methods Phys. Res. A
511, 210 (2003); Y. Akiba et al.: RIKEN Accel. Prog.
Rep. 38, 227 (2005).
3) Z. Li: BNL Internal Report, BNL Rep., No. 67527(2000); Nucl. Instrum. Methods Phys. Res. A 518, 738(2004).
4) Z. Li et al.: RIKEN Accel. Prog. Rep. 36, 250 (2003);
Nucl. Instrum. Methods Phys. Res. A 518, 300 (2004).
5) J. Tojo et al.: RIKEN Accel. Prog. Rep. 36, 252 (2003);
RIKEN Accel. Prog. Rep. 37, 251 (2004); IEEE Trans.
Nucl. Sci. 51, 2337 (2004).
6) Y. Akiba et al.: Proposal for a Silicon Vertex Tracker(VTX) for the PHENIX Experiment (Brookhaven National Laboratory, Upton, NY, 2004), unpublished.
7) http://www-cdf.lbl.gov/users/mweber/svx48) J. Asai et al.: RIKEN Accel. Prog. Rep. 38, 235 (2005).

RIKEN Accel. Prog. Rep. 38 (2005)

Aluminum bus development for silicon vertex detector
A. Taketani, H. En’yo, K. Fujii,∗1 K. Fujiwara, J. M. Heuser, H. Kano, Y. Inoue,∗2 H. Maeta,∗1 H. Ohnishi,
M. Tanaka,∗3 K. Tanida, and J. Tojo
A silicon vertex detector is planned to be implemented at the RHIC PHENIX experiment in order
to identify heavy ﬂavor quark decays by measuring adisplaced vertex.1) One of the major physics goal forthis new detector is the investigation of proton spin
structure and quark gluon plasma by identifying open
heavy ﬂavor production. The silicon vertex detector
will be located just outside of a beam pipe, where
proton-proton or heavy ion collisions occur. The detector consists of two major parts; the inner two layers
are pixel-type sensors2) and the outer two layers are
strip-type sensors.3)
The detailed structure of pixel detector is describedin Ref. 2. Signals from the sensor are fed into bumpbonded readout chips. The readout chips are connected to the readout bus, which is a printed circuitboard, with wire bondings. The readout bus is connected to front-end electronics4) that serve as interfaces to the PHENIX data acquisition system. We havebeen developing a thin printed circuit board with ﬁne
pitch patterns.
The silicon vertex detector is located at most innerpart of the PHENIX central arm. To avoid the generation of electrons by photon conversions resulting fromcollisions, the silicon vertex tracker is required to be
fewer radiation length on the detector material budget. In addition to the thin silicon sensor, the readout
bus should be fewer radiation length. Due to the highcharged particle multiplicity from heavy-ion collisions,the pixel sensor is segmented into 32 × 256 pixels of
50 × 425 µm2 size. Four hundred and eighty sensors
will be used in total and 3.9 M channels will be readout. Therefore the readout bus has to include 190 signal lines and several control lines as well power supply
and ground layers. The size of the bus is 1.4 × 40 cm2 .
Thus, the signal and control lines will be of 70 µm pitch
if we a choose double-layer bus. If we choose the triplelayer option, lines should be of 140 µm pitch.
In order to satisfy these two requirements, a thin
kapton-ﬁlm base and Al conductor are used, insteadof Cu, which is widely used for printed circuit boards.
A comparison of radiation length among the Cu andAl conductor boards is shown in Table 1. We assume 7-µm-thick bus line conductors, 50-µm-thickpower/ground layers and 22-µm-thick kapton layers
between conducting planes. The radiation length ofthe pixel sensor and readout chip is 0.36%. So the
Al conductor is desirable. However, the use of Al
is not common in the printed circuit board industry.
∗1
∗2
∗3

Hiroshima Kokusai Gakuin University
Rikkyo University
High Energy Accelerator Research Organization (KEK)

Table 1. Expected radiation length for the bus.
Configuration
Num. of signal layers
Radiation length

Al+Kapton23
0.17% 0.20%

Cu+Kapton23
0.9% 1.0%

Thus, we started to develop a ﬁne-pitch Al-kapton-baseboard by ourselves.
The board is manufactured by four major processes.
[1] Pattern etching, [2] formation of through-holes connecting conducting lines among diﬀerent layers, [3]stacking layers, and [4] plating with Ni-Au on wirebonding pads.
The pattern etching process proceeds in the following way. (1) The Al foil and kapton ﬁlm are attached;(2) they are pressed with heat so that they adhere
together; (3) photoresist is painted on the Al plane;(4) the line patterns are exposed; (5) unnecessary Al
is dissolved with acid or alkali; (6) the photoresist isremoved. The etching result is shown in Fig. 1. The
white lines are 12-µm-thick Al conductor and the black
plane is 12-µm-thick kapton-ﬁlm base. The lines are
40 µm in width and 120 µm in pitch. They are inspected using a microscope. Most of lines have good
shape. Some of lines show defects. It is expected that
this problem can be avoided by washing the surface
with sodium hydroxide before step (3). We are currently trying to fabricate a ﬁner pitch pattern.
After the etching of one side of the Al plane, an
Al foil is adhered to the other side. The formation ofthrough holes consists of two steps before the etchingof the new Al plane: (1) the formation of holes throughthe single Al-kapton layer, but not through the new Al
plane, by a laser drilling method, and (2) the plating with the Cu. 500-µm-diameter through holes are

Fig. 1. Etched pattern of the bus.

233

formed since the Cu in the through holes is a verysmall amount of material relative to the entire board
material. Figure 2 shows a cross-sectional view of thethrough hole. The white line is Cu plating which connects an Al conductor on the upper and a lower plane.
After the through-hole formation and the paintingof the photoresist on the newly adhered Al foil, newline patterns are aligned with the line patterns on theother side and etched. This technique is establishedwell for the popular Cu ﬁne-pitch board.
Subsequently, the steps of [1], [2], and [3] are repeated to build a multilayer board, Ni-Au plating iscarried out. Because kapton-Al-Au structure is too
soft for wire bonding, Ni is plated between Al and Au.
We tested the wire bonding on the Al-Ni-Au plated pad
using the Kulicke&Soﬀa Model 8060 automatic wedge
bonder with 25.4-µm-diameter Al wire. The bonding
strength is measured as 4.7 ± 1.6 g. Although it is necessary to tune the bonding parameter, the Al-Ni-Au
plating is satisfactory.
We have been developing a ﬁne-pitch Al-kapton bus
for the PHENIX pixel detector. We established major
key techniques for its fabrication.
References

Fig. 2. Cross-sectional view of through hole.

2341) Y. Goto et al.: RIKEN Accel. Prog. Rep. 37, 249(2004).
2) J. M. Heuser et al.: RIKEN Accel. Prog. Rep. 37, 250(2004).
3) J. Tojo et al.: RIKEN Accel. Prog. Rep. 37, 251 (2004).
4) H. Kano: RIKEN Accel. Prog. Rep. 37, 253 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Evaluation of silicon strip sensor for PHENIX upgrade
J. Asai, K. Boyle,∗1 Y. Akiba, A. Deshpande, D. E. Fields, Y. Goto, M. Hoeferkamp,∗2
A. Taketani, and J. Tojo
We are studying the characteristics of a quark
gluon plasma (QGP) and the spin structure of a proton using a relativistic heavy ion collider (RHIC)
at the Brookhaven National Laboratory (BNL). The
PHENIX is a device for detecting photons, electrons,muons, and hadrons with a high-rate data acquisition
capability from the collision of 100 GeV or 250 GeV
polarized protons. We plan to build the silicon vertex
tracker (VTX) in the PHENIX detector.1) The VTX
can identify the decay of heavy flavor mesons by theprecise measurement of the decay vertex. It can also
work function as a large solid angle charged particle
tracker.
The performance of silicon sensors decreases due toradiation damage during a detector running period.
Due to the damage, the leakage current also increases
gradually. The leakage current I [A] depends on thetemperature T [K].
I(T ) = AT 2 exp(−Eg /2kB T ).

Mexico and Stony Brook University. The main purposes of the QA program are the visual inspection ofeach sensor and the characterization measurements ofeach sensor. The bias-voltage dependences of the leakage current (I-V ) and the capacitance (C-V ) will bemeasured. In a clean room, they are measured using asemiautomatic probe station. Figures 2 and 3 show
the measurement system consisting of a probe station, a picoammeter/voltage source (Keithley 6487),
an LCR meter (HP 4263 B), and a switch scanner system (Keithley 7002), which are controlled using the
LabVIEW software through GPIB interface cables.
Now we are studying two sensors fabricated byHamamatsu Photonics and SINTEF. We will decide
the vender and the design of the sensors from the results of characterization measurements. As the next
step of the QA program, we will evaluate approximately 400 production sensors for PHENIX upgrade.

(1)Here, A is the sensor constant; Eg is the gap energy insilicon (Eg = 1.2 eV); and kB is the Boltzmann constant (kB = 8.6 × 10−5 eV/K). We measured the leakage current for the operation temperature. Figure 1
shows the temperature dependence of the leakage current of the sensor, which was measured for the first
prototype strip sensor tested with a beam at KEK 2002
in the temperature and humidity control chamber at
RIKEN. Each line shows a measurement for one biasvoltage setting. It is constant from 263 [K] to 283 [K] ata full depletion voltage (∼100 V). The operation temperature does not need to be less than 283 [K], because
the intensity of the noise signal from the leakage current does not decrease with the temperature.
Quality assurance (QA) for the VTX silicon stripixel
sensor will be carried out at BNL, University of New

Fig. 2. Semiautomatic probe station.

Fig. 3. Measurement system diagram.
Fig. 1. Leakage current distribution plotted against temperature T [K] dependence on bias voltage.
∗1∗2

Department of Physics and Astronomy, Stony Brook University, USA
Department of Physics and Astronomy, University of New
Mexico, USA

References
1) Y. Akiba et al.: Proposal for a Silicon Vertex Tracker(VTX) for the PHENIX Experiment (Brookhaven National Laboratory, Upton, NY, 2003).
2) Z. Li et al.: Nucl. Instrum. Methods Phys. Res. A 518,
300 (2004).

235

RIKEN Accel. Prog. Rep. 38 (2005)

PHENIX VTX simulation and reconstruction software(Status report)
V. L. Rykov and J. T. Mitchell∗
The simulation software for the PHENIX SiliconVertex Tracker (VTX) upgrade1,2) currently consistsof two main pieces:• The VTX part of the GEANT based PHENIX
simulation framework called PISA.
• The VTX hit simulation and reconstruction svx
package.
Since March 2004, both pieces for the VTX barrel are
publicly available from the PHENIX CVS repository.
In October 2004, the VTX endcaps have also been implemented in PISA by the Los Alamos PHENIX group.
The currently implemented barrel VTX geometry in
PISA emulates the main physics properties of the active parts of the detector as close to expectations as
is possible at the current design stage. On the other
hand, it is still ﬂexible enough for easy geometry modiﬁcations by changing a few parameters in the dataﬁle without editing and recompiling the PISA code.
This ﬂexibility was very helpful, when in May 2004,
the VTX was signiﬁcantly redesigned, switching from
1 pixel + 3 strip to 2 pixel + 2 strip layers with theoverall increase of dimensions.
Each VTX barrel layer represents a set of rotatedladders with adjustable overlap in azimuth of theneighboring ladders in order to recover the insensitive
areas at the sensor edges (see ﬁg. 1 of reference2) ).
In turn, each ladder consists of either silicon pixel3)
or strip4) sensors. At this stage of the project, the“add-ons” (electronic chips, buses, cooling pipes, support, etc.) are emulated with a passive aluminum layerof adjustable thickness on top of each silicon sensor.
Later on, as the design evolves, all passive VTX elements will be implemented according to the engineering drawings, which are not available yet.
In a PISA run, GEANT hits in the VTX sensors
are written into the PHENIX standard PISAEvent.root
ﬁle along with the hits from other PHENIX detectors.
At the next simulation stage, VTX hits are read by thesvx package code, and the “rawhits” and “clusters” arebuilt. “Rawhits” are the digitized electric signals inthe VTX pixels and strips, and “clusters” are reconstructed from rawhits candidates of particles crossing
areas in the VTX sensors, which then are used for reconstructing charged particle trajectories (tracks).
The current version of the svx package consists ofthe following branches of C++ classes:
SvxHit hierarchy is represented by the GEANT hit(“ghit”) class SvxGhit,a) rawhit class SvxRawhit,
and cluster class SvxCluster.
Hit relater branch is represented by three classes:
SvxGhitRawhit, SvxRawhitCluster and SvxGhitCluster. Each of these classes is a pair of hit ID
numbers, which relates two hits of diﬀerent types
and tells which hit of one type (e.g. ghit) contributed to the generation of the other type of hit
in the pair (e.g. cluster).
Data nodes SvxGhitList, SvxRawhitList, SvxClusterList, SvxGhitRawhitList, SvxRawhitClusterList,and SvxGhitClusterList, are the collections of therespective hits and their relaters in an event. After
processing each event, these data nodes are written into the output ﬁle and/or directly submitted
to the tracking code.
SvxSensor hierarchy consists of a number of classes
for the sensors of diﬀerent types.b) These are themost complex classes in the svx package, which
are doing the real job of generating rawhits fromghits and then ﬁnding clusters, using algorithms
and methods speciﬁc for a particular sensor type.
SvxReco class is the svx code run manager, which
also implements the interface to the PHENIX
analysis framework Fun4All.
The current version of the svx package covers only
the VTX barrel with no processing of endcap hits yet,and in general, still should be treated as the “1st iteration” of the VTX simulation and reconstruction software. Nevertheless, it is already widely used in the collaboration for the VTX performance simulations with
important contributions to the proposal1) on electronic
channel occupation, ghost hits, resolutions, etc. The
package is also used for the VTX tracking code development.
References
1) Y. Akiba et al.: Proposal for a Silicon Vertex Tracker(VTX) for the PHENIX Experiment (BNL, Upton, NY,
2004).
2) Y. Akiba et al.: RIKEN Accel. Prog. Rep. 38, 227(2005).
3) H. Ohnishi et al.: RIKEN Accel. Prog. Rep. 38, 230(2005).
4) J. Tojo et al.: RIKEN Accel. Prog. Rep. 38, 231 (2005).
a)
b)

∗

236

Brookhaven National Laboratory, USA.

SvxGhit objects are the reformatted copies of VTX GEANT
hits from PISAEvent.root file.
Currently, 1 type of pixel and 3 types of strip sensors are
implemented.

RIKEN Accel. Prog. Rep. 38 (2005)

Development of digital-pilot ASIC and data link system for PHENIX
pixel detector
H. Kano, A. Taketani, H. Ohnishi, M. Tanaka,∗1 J. M. Heuser, K. Fujiwara,∗2 and H. En’yo
The PHENIX collaboration has started a study for
an upgraded experiment for the eighth physics run at
RHIC in 2007/2008. Several new detector systems
will provide extended detection capabilities in collisions of heavy ion and polarized-proton beams when
RHIC reaches full operation at the design luminosity
in the next few years. The main PHENIX upgrade isa new vertex spectrometer installed between the polefaces of the central magnet. It combines high-precision
tracking for jet and heavy-flavor decay vertex measurements, electron identification and charged-particle
tracking in its subsystem silicon vertex detector, microTPC, and compact hadron blind detector. The siliconvertex detector comprises pixel and novel microstrip
sensors. The pixel detectors in the internal layer are
essential for resolving the high track densities in heavyion collisions.
The block diagram of the PHENIX pixel detector
readout system is shown in Fig. 1. The right-hand sideshows the control-room-located electronics, whereas
the left-hand side shows the on-detector electronics.
Comunication between the control room and the detector is via two optical fibers, one carrying clock,the other carrying trigger, configuration, and control.
Data transmission from the detector to the control
room is performed via 1.6 Gbps optical fiber-link.
The main components of the on-detector readout
electronics are ASICs. All the ASICs have been developed by IBM 0.25 µ CMOS technology with radiationhardening techniques. Precautions have been taken
to reduce malfunction due to single-event upset. The
digital-pilot ASIC (shown in Fig. 2.) performs the optical to electrical conversion of the incoming clock anddata signals, initiates the readout sequence in the readout chips, and sends data to the 1.6 Gbps ethernetlike serializer chip GOL.1) We modified the digitalpilot ASIC based on the ALICE chip architecture,2,3)

Fig. 2. Pictures of PHENIX digital pilot chip and internalcore (core size: 8 mm × 6 mm).

which has extended data bus width (16 bit to 32 bit)for PHENIX. This modification reduces the area of the
on-detector readout board and the number of chips.
In the PHENIX optical link between the controlroom and on-detector electronics, a serializer is used to
encode 32 bit words in a serial stream. The frequency
of input words is 40 MHz, while that of the output
stream is up to 1.6 Gbps. In this system, we chose
to use GOL (transmitter) and Vertex-2 pro (receiver).
The latest FPGA, Vertex-2 pro is suitable for our linksystem due to its built-in support for high-speed serial
links. The block diagram of the test setup is shown in
Fig. 3. The test signals generated by FPGA are sent
to the GOL test board through an optical transmitter and an optical fiber. The FPGA includes an encoder (8 b/10 b and gigabit ethernet) and a serializer.
An FPGA source code for the GOL has been developed, and we are checking speed (1.6 Gbps), error rate(< 10−15 ), and temperature in a long term test.

Fig. 3. Block diagram of test setup for link system.

References
Fig. 1. Block diagram of PHENIX pixel detector readout
system.

∗1∗21) http://proj-gol.web.cern.ch/proj-gol/proj%2Dgol/manuals/gol manual.pdf
2) P. Chochula et al.: Nucl. Phys. A 715, 849 (2003).
3) A. Kluge et al.: CERN 2001-005, 95 (2001).

High Energy Accelerator Research Organization (KEK)
Niigata University

237

RIKEN Accel. Prog. Rep. 38 (2005)

Field measurements in AGS warm snake†
J. Takano,∗1 M. Okamura, T. Hattori,∗1 R. Alforque,∗2 R. Belkin,∗2 G. Ganetis,∗2 A. Jain,∗2 W. W. MacKay,∗2
T. Roser,∗2 R. Thomas,∗2 and J. E. Tuozzolo∗2
A new warm snake has been produced by RIKEN
for the alternating gradient synchrotron (AGS) at
Brookhaven National Laboratory (BNL). The AGS
had a solenoidal Siberian snake for overcoming all imperfection depolarizing resonance, but the solenoidal
ﬁeld had caused transverse coupling resonance. This
warm snake is the world’s ﬁrst normal conducting helical dipole partial snake for overcoming all imperfection resonance and decreasing transverse coupling resonance. The relative heavy-ion collider has some superconducting Siberian snakes. These snakes have ahelical coil but no helical pole piece. A warm snake
has both a helical coil and a helical pole pieces madeof lamination steel. The magnetic ﬁeld of the warm
snake had been measured and compared with that obtained by 3D ﬁnite element calculations.
It is very important to calculate the magnetic ﬁeld
in 3D because the Siberian snake magnet has a helical magnetic ﬁeld. OPERA-3D/TOSCAa) was used tosimulate the ﬁeld of the warm snake. The simulation
models are shown in Figs. 1 and 2.
As shown in Fig. 1, the warm snake has three sections with diﬀerent pitches called a double-pitch structure. The pitches were optimized as the beam in thewarm snake has no position oﬀset at each end of thewarm snake or no deﬂection angle at the extractionof the warm snake. The optimized pitches are 132 cm
long with a pitch of 185 cm in the center slow-pitch
region and 39 cm long with a pitch of 90 cm at eachend of the rapid regions. The simulated proton beam
trajectory in the warm snake is shown in Figs. 3 and
4.
The warm snake had been designed and fabricatedin Japan. The picture of the completed warm snake isshown in Fig. 5.
The high-quality measurement of the magnetic ﬁeld
had been carried out in BNL. The probe for this measurement is a 51-mm-long harmonic coil.1) The longitudinal magnetic ﬁeld distribution in the warm snake
had been measured with a short harmonic coil. The
distribution is shown in Fig. 6. The transfer functions
at the center of the slow-pitch and rapid-pitch regions
had been measured. The graph of the transfer function
is shown in Fig. 7.
As shown in Fig. 6, the graph of 95% operating cur-Fig. 3. Transverse trajectory from 2 GeV to 25 GeV proton
beam.

Fig. 1. 3D simulation model of the warm snake on the
OPERA-3D/TOSCA.

Fig. 2. Helical coil in the simulation model of the warm
snake.
†
∗1
∗2
a)

238

Condensed from the Proc. EPAC 2004 (2004), p. 2116.
Tokyo Institute of Technology
Brookhaven National Laboratory, USA
Vector Fields Inc.

Fig. 4. Longitudinal trajectory of 2 GeV proton beam in
calculated magnetic ﬁeld of warm snake.

Fig. 5. Photograph of completed warm snake.
Fig. 8. Field proﬁles before and after error correction.

Fig. 6. Dipole ﬁeld distribution measured at three diﬀerent currents and simulation data of perfect model (nodeﬂection or oﬀset).

Fig. 7. Measured transfer functions.

rent is similar to that of the perfect model. The distribution at 2668A (100%) is higher than that of theperfect model. This result suggests the warm snake hassome fabrication errors. The reason for this increasein magnetic ﬁeld within the slow-pitch region is a decrease in the packing factor in the rapid-pitch region
because the end plates are bending out ward causedby the weight of the yoke itself and the magnetic force.
Therefore, the rapid-pitch region yoke saturates fasterthan the slow-pitch region as shown in Fig. 7.
To correct this error, a simulation model which includes the fabrication error was required. The magnetic ﬁeld of this error model is shown in Fig. 8 asplots of the error model. This model has almost thesame distribution as the perfect model. The parameters that were optimized were operating current andthe number of 6-mm-thick iron shims added to eachend plate. The results of the optimization indicatethat the operating current should be 2538A and one
shim should be added to each end plate.2)
The fabrication error of the warm snake was corrected by adjusting operating current and adding
shims. Several Siberian snakes had been measured
already and they are used in RHIC. However, thismeasurement for the warm snake is unique because
this magnet has the world’s ﬁrst double-pitch structure. Therefore, this measurement and the error correction method will be useful for Siberian snakes thathave a double-pitch structure. There is a plan to install AGS with a cold snake which is a superconducting
helical dipole partial snake with a double-pitch structure. Therefore, we have a chance to measure a snake
by the same method using cold snake.
References
1) A. Jain: Proc. CERN Accelerator School on Measurement and Alignment of Accelerator and Detector Magnets, Anacapri, Italy, 1997-4 (CERN, Geneva, 1998),
p. 1.
2) J. Takano: Master’s Thesis, Tokyo Institute of Technology (2004).

239

RIKEN Accel. Prog. Rep. 38 (2005)

Forward muon trigger upgrade for PHENIX experiment at RHIC
W. Xie, M. Grosse Perdekamp,∗ and D. Kawall, for PHENIX Collaboration
The measurement of the proton spin structure is oneof the main physics programs for the PHENIX experiment at RHIC. The early deep-inelastic-scatteringexperiment shows that quarks contribute about 20%of the proton spin. The other contribution shouldcome from gluon and parton orbital angular momenta.
The PHENIX experiment is able to determine thegluon contribution to the proton spin by measuring
the asymmetry of π 0 , direct photon, etc, and it is alsoable to determine quark and antiquark spin contributions by the measurement of single spin asymmetry of
decay leptons from W bosons produced via V-A interactions.1)√ In PHENIX, we plan to measure W in the
coming s = 500 GeV run by detecting electrons andmuons.
√The luminosity of the coming s = 500 GeV run is
32
expected to be as high as 2×10 cm−2 sec−1 , resulting
in a 12 MHz collision rate. The total number of events,
produced from W boson decay in the PHENIX muonarm, is expected to be approximately 104 . One criticalissue is whether the current the PHENIX muon trigger
has a suﬃcient rejection power to preselect all of these
events because the PHENIX data-acquisition system
bandwidth has the upper limit of 12 KHz. A simulation study shows that the maximum rejection factorof the current single-muon trigger is only about 500,
assuming the absence of beam-related backgrounds.
This corresponds to 24 KHz. A reasonable assignment of bandwidth resources for this speciﬁc trigger is
1–3 KHz. Therefore, we need at least tenfold increasein the rejection power of the current muon trigger tobe able to accept all events from W boson decay. An
upgraded muon trigger is required.
After testing many diﬀerent ideas, two methods were
found to be eﬀective in achieving a high enough rejection power for the W measurement. One is the installation of two new pad chambers with one in front ofmuon tracker station 1, and the other either behind theﬁfth gap of the muon identiﬁer or between the muontracker and the muon identiﬁer. The algorithm requires ﬁrst that hits from the two new pad chambers
be associated with the muon candidate of the existing
muon trigger followed by the application of the angle
cut between the two pad-chamber hits to reject lowmomentum muons. The other method is similar to theﬁrst one but the hits from the existing muon tracker
stations are utilized instead of building new detectors.
In this method, one has to redesign the existing muontracker front-end electronics. The ideas are shown in
Fig. 1. Both provide a suﬃcient rejection power for
preselecting all the events from W boson decay.
∗

240

University of Illinois at Ubrana Champaign, USA(a) New pad-chamber method(b) Redesign existing muon tracker electronics
Fig. 1. Two possible methods of muon trigger upgrade.

We have not ﬁxed the ﬁnal scheme of the trigger because there are many issues to be clariﬁed, such as theeﬀect of the beam-related background. The new pad
chamber method is expected to reject most of the background through the timing cut and may also improve
PHENIX muon-arm pattern recognition in most central Au+Au collisions. The method of replacing muontracker electronics can take advantage of the high granularity in the muon tracker but it will not improve pattern recognition and its performance might also be degraded by the beam-related background. The combination of the two methods is expected to provide evenhigher rejection power to enable PHENIX to do thesame physics in higher luminosity environment. Anyway, the simulation study is still on the way to checkdiﬀerent scenarios before the ﬁnal decision.
Various R&D projects related to the trigger upgrade
have been carried out or are ongoing. In Kyoto University and University of New Maxico, one muon-tracker
chamber prototype has been fabricated for a fast readout front-end electronic test. During the p+p run inyear 2003, at Riken-BNL Research Center and University of Illinois at Ubrana Champaign, a successful
measurement of the beam background has been carriedout and a more comprehensive new measurement will
be carried out in the p+p run in year 2005. All thesewill help determine the ﬁnal conﬁguration of the upgraded trigger which will start to be installed in year
2007.
Reference
1) G. Bunce et al.: Annu. Rev. Nucl. Part. Sci. 50, 525(2000).

RIKEN Accel. Prog. Rep. 38 (2005)

New scaler boards based on LBL/STAR design for PHENIX
M. Wagner,∗1 R. Bennett,∗2 A. Deshpande,∗2 Y. Goto, D. Kawall, and N. Saito,∗1
Within the measurement program at RHIC is an effort to understand the origins of the nucleon spin.1) At
RHIC, collisions of polarized protons at energies up tosqrt(s) = 200 GeV have been realized, and the crosssections required to produce various ﬁnal states havebeen measured with the PHENIX detector, and analysed for their dependence on the polarization directions of the colliding bunches.2,3) This requires that the
production rates of particular ﬁnal states are normalized to the luminosities of the colliding bunches so thatany remaining diﬀerences in production rates may beascribed to the spin-dependent eﬀects of interest. Since
the longitudinal proﬁles and numbers of protons in thecolliding bunches are typically diﬀerent, a reliable measurement of the relative luminosities of the colliding
bunches is required. In the PHENIX data acquisition (DAQ), an additional board has been introduced
into the Global Level 1 Trigger (GL-1), with scalers tomonitor the luminosity of each bunch crossing number(BCN) separately.2) Minimum-bias collisions are detected by a coincidence between the beam-beam counters (BBC), or with lower eﬃciency, by a coincidence
between the zero degree calorimeters (ZDC).2)
After hardware cuts are performed on the reconstructed vertex position, these GL-1P scalers count thetriggers from the BBC and ZDC as a measure of the luminosity for each BCN separately. For run01 throughrun04 the scalers performed suﬃciently well to obtain
the relative luminosities at the accuracy required forﬁrst measurements of asymmetries in inclusive π 0 production.3) Figure 1 shows a typical distribution for thecurrently used scaler systems with the clearly visible
variation of the counts (and hence luminosity) depending on the BCN.
Run04 was also used to obtain test data at very
high intensities in order to evaluate future hardware
requirements for a relative luminosity accuracy down
to 10−5 . For this issue, new scaler boards based on
a LBL/STAR design have been tested. For this test
and for the future use of these scalers, an interface
board which converts the RBIB signals from the GL-1
backplane into the required PECL signals was developed. The central unit of the interface board is a programmable Lattice ispXPDL 51024 MX chip, which
ensures the simultaneous distribution of possible 130
RBIB signals to four 25-pin outputs, which will be connected to the four available scaler boards in the ﬁnal
operation mode. The new scaler boards are signiﬁcantly diﬀerent from the currently used boards: while
the currently used scalers are not able to measure cor∗1∗2

Department of Physics, Kyoto University
State University of New York at Stony Brook USA

Fig. 1. GL-1P scaler entries vs. BCN (upper 2 panels:
BBC, lower 2 panels: ZDC).

relations between ZDC and BBC (e.g., applying conditions to ZDC while plotting BBC-distributions), thenew boards are designed on the basis of an 80 Mbyte
memory. This memory is required due to the input
design, which uses 24 inputs (i.e., 17 diﬀerent detector signals + 7 bits for 120 BCN applied simultaneously per board) as a bit pattern which reproduces 224
memory addresses at a 40-bits depth per address. Each
address represents a speciﬁc signal combination including the BCN. The 24 detector signals are gated by a
25th input, which is fed by the RHIC clock at 9.8 MHz.
One board was tested using signals from ERT triggers,
muon trigger and the aforementioned BBC and ZDC
signals. Since the boards are being tested for the veryﬁrst time, a comparison with the GL-1P modules isessential. A typical BBC distribution from the newscaler boards — similar to that shown in Fig. 1 — isshown in Fig. 2. The beam abort gaps between BCN
30 and 40 are clearly reproducible, although there is aclear BCN shift. The origins of this shift may be an
improperly timed ﬁducial signal from the V124 module, which is possibly also responsible for a signiﬁcantly
higher background, which is visible in the empty BCN,
while an expected electronic jitter or diﬀerent transition times within the interface board could be excluded
as shown in Fig. 3.
For future measurements an internal reset signal in
the interface board will be used instead of the external V124 ﬁducial signal. Despite these problems, thetest measurement could be used to analyse possible
saturation eﬀects at high intensities, which have been
detected with the GL-1P scalers, as shown in Fig. 4.
This eﬀect can be reproduced clearly by the new scaler

241

Fig. 4. BBC rate vs. ZDC rate measured with GL-1P
scalers. Left: low beam intensity, right: high beam
intensity.

Fig. 2. Results from the new scaler boards, showing BBC
trigger signals vs. BCN. Top: BBC N or S, center: BBC
wide vertex cut, bottom: BBC narrow cut.

Fig. 3. Transition times for 18 signals through the interface
board. The small size of these variations excludes themas the source of the background.

boards, as shown in Fig. 5. Moreover, the correlation
between other trigger signals (in Fig. 5: ertg1) andBBC or ZDC, respectively, is shown. This importantcomparison was not possible with the GL-1P scalers,due to their restriction to ZDC and BBC signals andit could indicate a nonlinearity problem of the ZDC
instead of the BBC at high beam intensities.
References
1) G. Bunce et al.: Annu. Rev. Nucl. Part. Sci. 50, 525

242

Fig. 5. Correlations with the new scaler boards. Upper
panels: same as Fig. 3. Lower panels: ertg1 trigger
signal vs. BBC (left) and ertg1 vs. ZDC (right), both athigh beam intensities (consider: arbitrary units).

(2000).
2) S. S. Adler et al.: Nucl. Instrum. Methods Rhys. Res.
A, 499, 560 (2003).
3) S. S. Adler et al. : Phys. Rev. Lett. 93, 202002 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

DAQ system upgrade of optical alignment system at
PHENIX muon tracker
H. Kanoh,∗1 T. Watanabe,∗1 T.-A. Shibata,∗1 A. Taketani, N. Kamihara,∗1
T. Horaguchi,∗1 and M. J. Kweon∗2
The optical alignment system (OASYS) is one of thesubdevices for the PHENIX muon tracker. The muontracker has threes layer of chambers termed station.
Each station is moved 200 to 300 micrometers by amagnetic ﬁeld or temperature excursion during the experiment period. In order to achieve better momentum
resolution, we correct these relative movements. The
purpose of the OASYS is the real-time monitoring of
the relative alignment among stations.
The OASYS consists of a light source at the 1st station, a convex lens at the 2nd station, and a CCD camera at the 3rd station, as shown in Fig. 1.1,2) When an
individual station moves, the image on the CCD camera moves. There are 7 sets of optics on each sectionof each station, and there are 7 × 8 × 2 = 112 optics
in total. By observing the position of the light spot on
the image of the CCD camera, we can monitor eachstation’s relative movement.
We have already modelled the relationship between
the CCD image movement and each station’s relative
movement.3) This model contains the 2nd station’s
parallel translation along the x and y axes and its rotation around the z axis. The accuracy of relative alignment using our model is estimated to be approximately
50 µm.
Figure 2 shows a block diagram of the current DAQ
system. Fifty-six signals from the CCD cameras are fed
into a multiplexor and one signal is fed into the PCI
capture board of a Windows PC. In the Windows PC,
histograms are generated, which are projected images

Fig. 1. Optical alignment system.
∗1∗2

Department of Physics, Tokyo Institute of Technology
Department of Physics, Korea University, Korea

Fig. 2. Schematic of DAQ system.

along the vertical or horizontal axis, and then stored
on the hard disk of the Windows PC and a Linux server
through SAMBA. Then, on the Linux server, we obtain the position of the light spot via a Gaussian ﬁt,using ROOT. We replaced the old GUI base DAQ
system with the LabVIEW base system this summer.
LabVIEW is commercially available software, which
is widely used in the monitor and control industry.
The stability of the system is improved and the datataking speed increased from 1 image/30 min/camera to
1 image/10 min/camera.
As another upgrade, the image processing procedure
is improved as detailed below. In the old method, datafrom all vertical pixels in the CCD image are used forgenerating horizontally projected histograms and viceversa. Only the vertical pixels that contribute to thepeak image are selected. In this way, the sharpnessof the peak images is improved. Second, we superimpose images that are sequentially taken over approximately 1 second (16 at least and 128 maximum), andthe background noise is averaged and statistical ﬂuctuations are minimized. Thus, the peak position accuracy is improved. Figure 3 shows the eﬀect of these
improvements. The two raw sets of the date on the
top are histograms produced by the old system and,the two raw sets of date on the bottom are histograms
produced by the new one. The same CCD cameras
are used for each histogram. It is diﬃcult to ﬁnd thepeak in the histograms produced by the old system,
but very easy in that prodeced by the new system.

243

As a result of this upgrade, the number of camerasthat can be used for relative alignment increases from75 to 96. In addition, the S/N ratio increases from
1.4 to 12 at maximum (S/N = 0.2 is taken as a cut
threshold for image analysis).
References
1) J. Murata et al.: Nucl. Instrum. Methods Phys. Res. A
500, 309 (2003).
2) N. Kamihara: Master Thesis, Tokyo Institute of Technology (2002).
3) T. Watanabe: Master Thesis, Tokyo Institute of Technology (2004).
Fig. 3. Comparison of old DAQ and upgraded DAQ.

244

RIKEN Accel. Prog. Rep. 38 (2005)

Status of fragmentation function analysis at BELLE
D. Gabbert,∗1,∗3 M. Grosse Perdekamp,∗1 K. Hasuko, A. Ogawa,∗2 and R. Seidl∗1
The BELLE experiment at the asymmetric e+ e−
collider KEK-B in Tsukuba, Japan, is mainly dedicated to investigate CP violation in B meson decays. It
is tuned to the Υ(4S) resonance at 10.58 GeV, whereas
background studies are performed at 10.52 GeV. These
continuum events are studied in order to measure spindependent and precise spin-independent fragmentation
functions.
Spin-independent fragmentation functions are mea1 dσhsured as normalized cross sections σtot
dz . The available global data on the normalized hadronic cross section1) in the high region of the fractional energy z islimited. In particular, at low center of mass energies,
precision fragmentation function data is not available.
Consequently, the behavior of fragmentation functions
at a large z is only poorly understood and its separation into diﬀerent parton ﬂavors involves signiﬁcant uncertainties, which particularly aﬀect the understanding of semi-inclusive measurements in HERMES, COMPASS and RHIC experiments. Fragmentation functions for identiﬁed hadrons h will, for instance, enter a global QCD analysis of double-spinpolarized asymmetries AhLL at RHIC with the goal of
extracting gluon polarisation. Presently, such an analysis suﬀers from uncertainties in the gluon fragmentation in current fragmentation parameterizations.2,3)
One can extract the gluon fragmentation functions
from QCD evolution by combining fragmentation functions at higher center of mass energies from LEP and
SLAC with data at lower energies, at which BELLE
can contribute signiﬁcantly with its good detector performance and high statistics of more than 30 fb−1 inthe oﬀ-resonance sample.
Unpolarized fragmentation functions and their systematic eﬀects are presently being investigated at
BELLE. We have made signiﬁcant progress in the
study of momentum smearing and particle identiﬁcation. Momentum smearing was studied in order to select an appropriate binning and to estimate the resulting error. Corrections for particle identiﬁcation (pid)were studied using Monte Carlo techniques, see Fig. 1
and data: A study using pions and kaons from theD* decay revealed a good agreement between the pid
eﬃciencies derived from Monte Carlo and data.
A second analysis adresses the fragmentationof transversely polarized quarks into pseudoscalar

∗1
∗2
∗3

Fig. 1. Fragmentation functions for identified hadrons in
MC after performing pid corrections, errors indicate
statistics for 1.4 fb−1 .

hadrons, also known as the Collins function.4) Thisfunction is necessary to access the transversity quark
distribution function, which, due to its chiral-odd
nature, can only be measured in conjunction witha chiral-odd fragmentation function in semi-inclusive
channels. The quark-antiquark pair created as a resultof electron-positron annihilation can possess a net antialignment in their transverse spins. During the fragmentation, these transversely polarized (anti) quarks
pick up transverse momenta. One can then measure
the resulting azimuthal distributions of two hadrons in
opposite hemispheres along the thrust axis, relative tothe production plane, to obtain a combination of quark
and antiquark Collins functions.
References
1) O. Biebel, P. Nason, and B. R. Webber: Phys. Rev. D
66, 010001 (2002).
2) S. Kretzer: Phys. Rev. D 62, 054001 (2000).
3) B. A. Kniehl, G. Kramer, and B. Potter: Nucl. Phys. B
582, 514 (2000).
4) J. C. Collins: Nucl. Phys. B 396, 161 (1993).

University of Illinois, USA
Brookhaven National Laboratory, USA
Technische Universität München, Germany

245

RIKEN Accel. Prog. Rep. 38 (2005)

Spin transfer to Λ+c hyperons in polarized proton collisions at RHIC
V. L. Rykov and K. Sudoh
Helicity transfer to inclusive charmed Λ+c hyperons
in polarized proton collisions has been recently proposed as a probe for the polarized gluon distribution ∆G/G of proton.1) It has been estimated that,with
the integrated luminosity of 320 (800) pb−1 at√
S=200 (500) GeV, the achievable at RHIC statisticalerrors for the helicity transfer parameter DLL a) could
be small enough for distinguishing, for example, thepopular AAC 2) and GSRV 3) models for ∆G/G.
Compared to the usually considered for these pur+++−poses cross-section asymmetry ALL = σσ++ −σ+σ +− ,
where σ ++ and σ +− are the cross sections for the sameand opposite helicities of colliding protons, spin transfers are linear with ∆G/G while ALL ∝ (∆G/G)2 .
This means that spin transfers might become more sensitive probes for polarized gluon distribution if ∆G/G
appeared to be unexpectedly small. The other difference is that, unlike ALL , measuring spin transfers
generally does not require monitoring the relative luminosity of collisions with diﬀerent polarizations of initial protons, which is always considered as a potential
source of systematic errors. And, in general, measuring a number of sensitive characteristics rather than
one and comparing them to the predictions of theoretical models could serve as a good consistency check of
the model’s assumption.
In report,4) we extended the analyses1) to the proton
helicity correlations with the Λ+c transverse polarization component in the production plane (parameter
DLS ). The DLS is also expected to be nonzero at Λc ’stransverse momenta PT of a few GeV/c due to thelarge c-quark mass. Moreover, for each spin transfer,++
LL and LS, we evaluated two more observables, DLΠ
+−and DLΠ , Π = L, S, which will actually be measured
at RHIC in collisions of two polarized protons of thesame and opposite helicities, respectively. Then, parameters DLΠ for collisions of polarized protons at unpolarized can be determined as the weighted averages+++−
and DLΠ:of DLΠ
DLΠ =

1 ++
+−
[D (1 + ALL ) + DLΠ
(1 − ALL )]
2 LΠ

(1)

In turn, if all three D’s for the same ﬁnal spin component were measured, then ALL can be derived, using
Eq. (1), with the result, as it mentioned above, potentially free from systematics due to monitoring the relative luminosity of collisions with diﬀerent beam polarizations. With this approach, the ALL statistical errors
would usually be larger than of “direct” measurements.
However, if the systematics rather than statistic is an
issue, then using spin transfers and Eq. (1) could bea)246

ALL in the notations of papers.1)

an option.
In Fig. 1, the leading order calculations for pseudorapidity dependences of 6 spin transfer parameters, averaged over PT interval from 2 to 5 GeV/c, are shown.
These results have been obtained, using the assumptions and techniques of the papers.1) The same spin dependent fragmentation function ∆D(z) = C(z) · D(z)have been used for both the longitudinal and transverse spin transfers from c-quark to Λ+c , where D(z) is
the “unpolarized” quark fragmentation function. For
the C(z), two option are compared: C(z) = 1 andC(z) = z. One can observe that, in the central region of |η| < 1, both, DLL ’s and DLS ’s are of about
the same size ∼5–15%. As η increases, all DLL ’s grow+−up to ∼20–30% for the AAC model, while DLS
stays
virtually ﬂat. The achievable at RHIC statistical errors of about 1% are small enough to clearly separate
predictions for the shown models.

Fig. 1. η-dependences of spin transfer parameters for inclusiveΛ+c production in polarized proton collisions at√
S= 200 GeV. The statistical errors are for the integrated luminosity of 320 pb−1 and beam polarization
70%. See text for details.

References
1) K. Ohkuma, K. Sudoh, and T. Mori: Phys. Lett. B 491,
117 (2001); K. Ohkuma and T. Mori: hep-ph/0306285.
2) Y. Goto et al.: Phys. Rev. D 62, 034017 (2000).
3) M. Glück et al.: Phys. Rev. D 63, 094005 (2001).
4) V. L. Rykov and K. Sudoh: Proc. 16th Int. Spin Physics
Symp. (SPIN2004), Trieste, Italy, 2004-10 (to be published); hep-ph/0412244.

RIKEN Accel. Prog. Rep. 38 (2005)

CCJ operation in 2003–2004
S. Yokkaichi, Y. Goto, H. Hamagaki,∗ T. Ichihara, O. Jinnouchi, A. Kiyomichi, Y. Watanabe, and H. En’yo
The operation of CCJ,1–3) RIKEN Computing Center in Japan for RHIC4) physics, started in June
2000 as the largest oﬀ-site computing center for the
PHENIX5) experiment at RHIC. CCJ performs, in
PHENIX computing, the three roles of 1) the simulation center, 2) the Asian regional center and 3) the
center of spin physics. Recently, DST (Data SummaryTape) production from raw data has become more important.
Many analysis and simulation projects are being
carried out at CCJ, including some PHENIX oﬃcial
projects. They are shown on the web page:
http://ccjsun.riken.go.jp/ccj/proposals/. The reportfrom each project is described in this volume.
We have approximately 180 PC nodes operated using Linux, 166 are calculation nodes and the others
are service nodes. Each calculation node has 1 GB ofmemory, 2 GB of swap area, 10–31 GB of local work
area and dual CPUs (Pentium III 700 MHz–1.4 GHz,
Pentium 4 2.0 GHz). Red Hat 8.0/kernel 2.4.20 is operated on the calculation nodes, the same as at the
RCF (RHIC computing facility),6) which is the main
analysis facility for the PHENIX. The upgrade to Red
Hat 8 was carried out in Jan. 2004.
We also have six SUN servers operated using Solaris, one is a service node and ﬁve are data servers,
which are connected to large RAID systems (38 TB in
total) and operated as NFS servers. Service nodes areused for various purposes such as a login server from
WAN, a database server for analysis, an AFS client
to share the PHENIX computing environment. Calculation nodes are connected with 100Base-T and dataservers are connected with 1000Base-SX via a gigabit
switch. Gigabit switch Alteon ACE 180 was replaced
by Cisco Catalyst 4506 in Feb. 2004.
HPSS7) 4.5 is used as a mass-storage system in CCJ,
the same as RCF. Approximately 180 TB/650000 ﬁlesof data have been stored in CCJ-HPSS as of Oct.
2004. Five IBM p630 servers operated using AIX areused as the HPSS core server and data/tape movers.
Eight 9940B tape drives (30 MB/s I/O & capacity
200 GB/cartridge) and 3000 tape cartridges in a StorageTek PowderHorn 9310 tape robot are available.
The robot can handle approximately 5000 tapes, thus
we can extend the total tape capacity to 1 PB. The
upgrade to the current HPSS system was carried out
in Nov. 2003, as a part of the RIKEN Super Combined Cluster System (RSCC),8) which is explained in
the following section. We also have a tape duplication
facility at BNL which consists of an IBM p630 server
and two 9940B tape drives.
∗

On the calculation nodes, the batch queueing system
LSF9) 4.2 was operated and upgrading to LSF 5.1 wascarried out in Apr. 2004.
In Mar. 2004, the AFS client was upgraded from a
SUN WS to a PC (Pentium III 1.4 GHz/memory 1 GB)
using OpenAFS on Linux. In Jun. 2004, a PC (dual
Xeon 2.6 GHz/memory 2 GB) functioning as an NFS
server was deployed which was connected to an 8 TB
FC RAID system.
The DB system for PHENIX analysis was gradually
being changed from Objectivity/DB (OBJY) to PostgreSQL this year. The last OBJY update at PHENIX
was in Jun. 2004. The limited support of PostgreSQL
in CCJ started in Apr. 2004.
RSCC was deployed in Mar. 2004 by the RIKEN
Advanced Center for Computing and Communication.
Integrated operation between RSCC and CCJ was investigated from 2003, and opened for users in May
2004. RSCC includes 1024 nodes/2048 CPUs of PC
clusters and HPSS as a mass-storage device, which isshared with CCJ.
As calculation nodes, 128 PC nodes (dual Xeon
3.06 GHz/2 GB memory/100 GB local disk), forming
the ‘pc2c’ cluster in RSCC are dedicated to CCJ. Ourdata servers and HPSS can also be accessed by thesenodes the same as for our old PC nodes. In particular, the user’s home area and the PHENIX computing
environment are shared using NFS.
As a batch queueing system, NQSII/ERSII (madeby NEC) is operated in the pc2c cluster. For the time
being, the performance of the system is insuﬃcient for
our usage in experimental nuclear physics, e.g., to process up to 1000–10000 jobs per day. The redundancyof the system is also worse than that of LSF. Improvement or replacement should be planned.
To estimate how appealing our CPU power is tousers, we examine the ‘obsolescence index (OI)’, which
is deﬁned as the ‘total CPU power in the cluster’ divided by the ‘fastest desktop CPU power available inthat year’. In other words, the cluster is equivalent
to the fastest desktop PC × OI for that year. If there
is no CPU upgrade, the OI decreases because CPUs
become faster year by year. Here, the ‘eﬀective CPU
power’ is measured using a typical PHENIX softwareand normalized with respect to 1 GHz Pentium III.
The trend of the OI of CCJ (building commenced
in 1999) is shown in Fig. 1. It shows that, at the endof JFY 2004, the fastest Intel CPU is estimated to be
4.2 GHz (solid triangles), CCJ (with RSCC pc2c) havecalculation power equivalent to approximately 1100
Pentium III 1 GHz CPUs (solid squares) and equivalent to approximately 250 of the fastest available CPUs

Center for Nuclear Study, University of Tokyo

247

Fig. 1. Obsolescence index (OI) of CCJ.

(open squares) for the PHENIX software. RSCC madeCCJ very appealing in terms of CPU power.
Here, we report hardware problems that occurred in
the term of Dec. 2003–Nov. 2004. Concerning the PC
nodes, 10% of nodes were down due to various problems involving the cooling fan, disk, memory, CPU andpower supply. In total, 25% of calculation nodes has
been down because 15% were down in the previous
year.2) The problems occurred in the older (and slower)
node group purchased in JFY 1999–2001. There were
almost no problems with the newer (and faster) nodegroup purchased at the end of JFY 2001 including
Linux Networx R-Cluster and IBM xSeries 330. Concerning the SUN servers, M/B replacement in Mar. andmemory & CPU replacement in Oct. were the only two
problems that required the shutdown.
Concerning the RAID systems, the controller, cable,
FC-hub and I/F card problems which caused a diskoﬄine are approximately 10 times including two casesthat required the shutdown of the servers. Simple disk
failure is not included because disks comprising RAID
are hot swappable. The old problematic 3.2 TB SCSIRAID purchased in JFY 1999 was retired in Mar. 2004.
The disk-failure rate of the old 6 TB FC RAID purchased in JFY 2000 became very high (4 times/monthor more) this year. We could not neglect the probability of the simultaneous failure of two disks, which
could cause the loss of data, therefore we retired the
RAID in Dec. 2004.
The air-conditioning system in the machine room
was down on Mar. 9, 2004, which was caused by amistake by the building maintenance staﬀ. A highroom temperature for 6–8 hours could have damaged248

the hardware, although data were not lost in this case.
The most serious problem occurred in Feb. 2004,
that is, an operational error of the disk caused a loss ofdata in the user’s home area. Although backup data
was restored, the data updated in the previous 7 days
were lost. (Backup using the dump command was operated once a week. Unfortunately, the accident occurred on the 7th day.) Backup using rsync once a
day was also started after the accident.
In PHENIX Run4 (2003/11–2004/5), approximately
200 TB of raw data for the heavy-ion collision experiment and 20 TB for the p-p collision experiment wererecorded. The transfer of the p-p data from BNL to
RIKEN via WAN was carried out and a transfer rateof approximately 100 Mbps (12 MB/sec) for 24 hours(or more) was achieved using bbftp.10) In the test, approximately 70 MB/s was achieved using GridFTP.11)
The project to transfer the Run5 (2004/11 ∼) data
via WAN is planned to produce DST in CCJ, particularly for the p-p collision data. The amount of dataof Run5 will be approximately 200–400 TB for just thep-p data for 2–3 months. If a transfer rate of 70 MB/s(= 6 TB/day = 180 TB/month) cannot be maintained
continuously, transfer using tape will also be required.
The following tasks should be processed in the next
several months: upgrade to Scientiﬁc Linux 3 (and LSF
6.0) on the calculation node, reinforcement of the DB
server for PHENIX, improvement of the batch queueing system of the pc2c cluster in RSCC, establishmentof the (semi-)automatic data-transfer procedure fromthe PHENIX counting house and the eﬃcient data-I/O
procedure for the p-p DST production at CCJ.
References
1) http://ccjsun.riken.go.jp/ccj/
2) S. Yokkaichi et al.: RIKEN Accel. Prog. Rep. 37, 257(2004).
3) Y. Watanabe et al.: RIKEN Accel. Prog. Rep. 36, 262(2003); T. Ichihara et al.: RIKEN Accel. Prog. Rep.
35, 236 (2002).
4) http://www.bnl.gov/rhic5) http://www.phenix.bnl.gov6) http://www.rhic.bnl.gov/RCF/7) http://www.hpss-collaboration.org/
8) http://rscc.riken.jp
9) http://www.platform.com/products/LSF/10) http://doc.in2p3.fr/bbftp/
11) http://www.globus.org/datagrid/gridftp.html

RIKEN Accel. Prog. Rep. 38 (2005)

Pumping 229m Th by hollow-cathode discharge [II]S. Enomoto, H. Haba, M. Hara,∗1 T. T. Inamura, Y. Kasamatsu,∗2 H. Kikunaga,∗3 T. Mitsugashira,∗1
T. Nakanishi,∗3 T. Ohtsuki,∗4 A. Shinohara,∗2 K. Takamiya,∗5 A. Yokoyama,∗3 and H. Yuki∗4
We proposed a new method for pumping 229m Th byhollow-cathode discharge and built a hollow-cathodetube that was specially designed to measure α particles from 229m Th.1) After making a small but decisive
alternation around the insulation between the anodeand the hollow cathode, we successfully made Ar-gas
discharge stable as long as we wanted with 229 Th (0.1–
0.2 µg) loaded into the hollow cathode. Usually, we use
Ar gas at a pressure of 200 Pa, a discharge current of
100 mA or 200 mA and a voltage of about 300 V (constant current mode). These discharge conditions arecomparable to the standard conditions in the hollowcathode tube for atomic spectroscopy, and we can excite atomic states up to about 10 eV in Th i (neutralatom) and Th ii (singly charged atom). This was conﬁrmed by preliminary experiment with natural Th using the UV spectrograph at the Poznan University ofTechnology in 2002.2)
From the level systematics in this mass region, theground state of 229 Th has been assigned to the Nilsson orbital 5/2+ [633],3) and similarly, the so-called
3.5-eV isomer4) is considered to be 3/2+ [631] if it exists. Consequently, as we reported at an international
workshop this year,5) one can expect four signiﬁcant αtransitions from 229m Th to the known levels of 225 Ra:
4930-keV α transition to the Iπ = 3/2+ (3/2+ [631])
level at 149.96 keV, 5036-keV to 3/2+ (1/2+ [631]) at
42.77 keV, 5053-keV to 5/2+ (1/2+ [631]) at 25.41 keV,and 5079-keV to 1/2+ (1/2+ [631]) at the ground state.
The ﬁrst two transitions are expected to be strongly
favored.6) Although we started this experiment by assuming its half-life to be about 14 hours according toRef. 6, measurements were performed successively for aperiod of 10 minutes, 20 minutes after switching oﬀ thedischarge that was kept at 100 mA for 3 hours. Figure 1 shows α spectra observed 20 minutes (●) and17 hours (□) after switching oﬀ the discharge. The
observed four distinct peaks mainly come from the αdecay of the ground state of 229 Th (T1/2 = 7340 y). As
indicated in Fig. 1, however, there seems to be a traceof 5036-keV transition only in the ﬁrst spectrum (●),
which is likely to have a decay half-life shorter than 20
minutes. At present, it is hard to make a deﬁnite statement about whether the isomer was really pumped. To
conﬁrm this, we will perform an in-beam measurement,
∗1
∗2
∗3
∗4
∗5

Fig. 1. Alpha spectra observed 20 minutes (●) and 17
hours (□) after switching oﬀ the discharge in thehollow-cathode tube loaded with 229 Th (0.1 µg or about
1 kBq). An arrow indicates an energy of 5036 keV thatis likely to coincide with the probable α transition from
229m
Th.

i.e., a measurement during the discharge. The half-lifeof the isomer could be even shorter than a few minutes.
The in-beam measurement will be made at the Oarai
Branch of the Institute for Materials Research, Tohoku
University.
References
1) H. Haba et al.: RIKEN Accel. Prog. Rep. 37, 263(2004).
2) B. Arcimowicz, S. Chojnacki, and T. T. Inamura: Annu.
Rep. 2002, Heavy Ion Laboratory, Warsaw University(2003), p. 43.
3) R. B. Firestone, V. S. Shirley, C. M. Baglin, S. Y. F.
Chu, and J. Zipkin: Table of Isotopes, 8th ed. (Wileyand Sons, New York, 1996).
4) R. G. Helmer and C. W. Reich: Phys. Rev. C 49, 1845
(1994).
5) T. T. Inamura, T. Mitsugashira, and the Oarai Collaboration: Int. Workshop on Laser Methods in the Study of
Nuclei, Atoms and Molecules, Poznan, Poland, May 2327, 2004; the proceedings will be published in HyperﬁneInteract. in 2005.
6) T. Mitsugashira et al.: J. Radioanal. Nucl. Chem. 255,
63 (2003).

Oarai Branch, Institute for Materials Research, Tohoku University
Graduate School of Science, Osaka University
Graduate School of Science, Kanazawa University
Laboratory of Nuclear Science, Tohoku University
Research Reactor Institute, Kyoto University

249

RIKEN Accel. Prog. Rep. 38 (2005)

Carbon-nanoparticle formation from Teflon
through rf-discharge processes
O. Kamigaito and T. Kobayashi
It was found that carbon-nanoparticles are formed
from Teﬂon (PTFE: polytetraﬂuoroethylene) throughrf-discharge processes in the atmosphere. This phenomenon was formerly observed in an rf breakdown ina feeder line of a RILAC cavity, where vast amountsof black ashes were generated from a small portion of
the Teﬂon insulator. We conﬁrmed the formation in anexperiment using an rf resonator, as described below.
Figure 1 (a) shows a schematic drawing of the experimental set-up. A coaxial resonator, which wasused for testing the ﬂat-topping system of the AVF cyclotron,1) has been modiﬁed by attaching a spark gap
at the open end. The resonant frequency, Q-value andshunt impedance of the resonator are 80 MHz, 5200
and 615 kΩ, respectively. The pulsed rf signal from asignal generator (Agilent E4436B) is ampliﬁed througha wide-band ampliﬁer (Thamway A145-6767A), which

has a gain of 60 dB with a maximum power output
of 5 kW, and fed into the resonator with a capacitive
coupler. The gap voltage is monitored by a capacitive
pickup probe.
The spark gap is shown in Fig. 1 (b). The gap between the two copper electrodes is surrounded by a
Teﬂon cylinder, which contains Teﬂon powder in it.
The pulse width and the repetition rate of the signal
generator were set to be 20 µs and 1 kHz, respectively,
as shown in Fig. 1 (c). When the gap voltage Vg , shownin Fig. 1 (c), exceeded 35 kV, discharge occurred in the
Teﬂon cylinder. Soon the gap became conductive andit was found that some portion of the Teﬂon powder
had burned; black ashes were generated between the
gap as shown in Fig. 1 (b).
A typical SEM image of the ashes is shown in Fig. 2,
where clusters of ﬁne particles of 30–80 nm in diameter are observed. Analyses using TEM/EDX haveshown that these nanoparticles mainly consist of carbon. A smaller amount of ﬂuorine is also observed in
the nanoparticles.
It has been shown by TEM and electron-diﬀraction
analyses that the nanoparticles have an amorphous
structure. Further investigation on the structure aswell as their formation process is under way.

Fig. 2. SEM image of nanoparticles formed from Teflon,taken using Hitachi 300 kV FE-STEM. A single unit of
the scale corresponds to 30 nm.

Fig. 1. (a) Schematic drawing of experimental set-up. (b)Spark gap and Teflon cylinder containing Teflon powder. (c) Time sequence of gap voltage.

250

Reference
1) S. Kohara et al.: Proc. 12th Symp. on Accelerator Science and Technology, Wako, 1999-10 (1999), p. 227.

RIKEN Accel. Prog. Rep. 38 (2005)

Eﬀects of plasma electrode position on beam intensityand emittance of RIKEN 18 GHz ECRIS
Y. Higurashi, T. Nakagawa, M. Kidera, T. Aihara,∗ M. Kase, and Y. Yano
To improve the performance of the RIKEN 18 GHzECRIS, we intensively studied the eﬀect of the plasma
electrode position on the beam intensity of heavy ions
during the past several years.1,2) In previous experiments, we investigated the eﬀect of the plasma electrode position on the beam intensity of Ar8+,9+ andincreased the beam intensities up to the order of mA.3)
However, the eﬀect of plasma electrode position on the
beam intensities of heavier ions (Kr and Xe ions) is still
not clear. Furthermore, such a beam intensity shouldaﬀect the beam quality (emittance, brightness and soon).4) In this paper, we report on the eﬀects of theplasma electrode position on the beam intensity of Ar,
Kr and Xe ions, and the emittance of intense heavy
ion beam.
Figure 1 shows the position of the movable plasma
electrode and beam extraction side. The diameter ofthe plasma electrode hole was 10 mm. The distance
between the extraction electrode and the plasma electrode was ∼ 15 mm. The hole diameter of the extraction electrode was 12 mm.
In a previous paper,3) the plasma electrode position
for maximizing the beam intensities of Ar8+,9+ was
found to be at electrode position C (see Fig. 1). To
investigate the eﬀect of electrode position on the beam
intensities of Kr and Xe ions, we measured the beam
intensities as functions of plasma electrode position.
We chose four positions (position A (edge of hexapole
magnet), B, C, and D (within 2.5 cm from the edge ofthe hexapole magnet) as shown in Fig. 1. The otherparameters (magnetic ﬁeld, gas pressure, biased discposition, and negative bias voltage of disc) were tuned
to maximize the beam intensity.
Figure 2 shows the charge distributions of Ar, Kr
and Xe ions produced from the RIKEN 18 GHz ECRIS
at plasma electrode position C. The ion source wasFig. 1. Cross-sectional view of movable plasma electrodeand beam extraction side of RIKEN 18 GHz ECRIS.5)∗

SHI Accelerator Service, Ltd.

Fig. 2. Charge distribution of the Ar, Kr and Xe ions.

tuned to produce Ar8+ , Kr13+ and Xe18+ ion beams.
Beam intensities of Xe18,20+ increased from 0.2 to
0.3 emA, when the plasma electrode was moved fromposition A to C. At plasma electrode position C, beam
intensities of 0.6 mA of Kr13+ , 0.5 emA of Kr14+ and
0.3 emA of Xe18,20+ were extracted at the RF powerof ∼ 700 W.
Figure 3 shows the beam intensities of Ar, Kr and
Xe ions at plasma electrode positions A and C. We
observed that the beam intensities of medium charge
state Kr and Xe ions were strongly enhanced at plasma
electrode position C, which is the same tendency observed in Ar ion production. Figure 4 shows the beam
intensities of Ar, Kr and Xe ions as functions of plasma
electrode position. It is clearly seen that beam intensities of lower charge state heavy ions increased as was
plasma electrode moved toward the ECR zone.
Figure 5 shows the beam intensities of Ar, Kr and
Xe ions as functions of RF power at plasma electrodeposition C. The ion source was tuned with 600 W of
RF power and then the RF power was changed withoutchanging any other parameters. It should be stressedthat the beam intensity is not saturated at the maximum RF power in this experiment. This means thathigher beam intensities can be realized at higher RF
powers.
Measurements of the emittance both horizontallyand vertically were performed over a wide range of the251

Fig. 3. Beam intensities Ar, Kr and Xe ions at plasma electrode positions A and C.

Fig. 5. Beam intensities of Ar, Kr and Xe ions as functionsof RF power at plasma electrode position C.

Fig. 4. Beam intensities of Ar, Kr and Xe ions as functionsof plasma electrode position.

drain current of the RIKEN 18 GHz ECRIS. Figure 6
shows the normalized 99% emittance of Ar8+ as a function of drain current. It is clearly seen that the emittance gradually increased from 0.5 to 1.1π mm mradwith increasing the drain current from 4 to 15 mA. At
the highest drain current, the beam intensity of Ar8+
was 1.5 emA at the extraction voltage of 17 kV. In thiscase, the unnormalized emittance was 420π mm mrad,
which is 3 times as large as the acceptance of our RFQ
linac (acceptance is 150π mm mrad).6) To accelerate
the full beam of 1.5 mA Ar8+ under this condition, we
require the extraction voltage of 60 kV. At a low draincurrent, 90% of the Ar8+ beam will be accepted by
the RFQ linac at the extraction voltage of 20 kV. The
emittances of the Xe20+ beam were 0.45 and 0.47π mm
mrad for the drain currents of 3.5 and 1.5 mA, respectively. It seems that the emittance is almost constant252

Fig. 6. Normalized 99% emittance of Ar8+ as a function ofdrain current.

at low drain current. In this test experiment, other effects (such as beam instability) may be larger than thespace charge eﬀect. To understand these phenomena,
we need to conduct further investigations.
References
1) Y. Higurashi, T. Nakagawa, M. Kidera, T. Aihara, M.
Kase, and Y. Yano: Rev. Sci. Instrum. 73, 598 (2002).
2) Y. Higurashi, T. Nakagawa, M. Kidera, T. Aihara, M.
Kase, and Y. Yano: Jpn. J. Appl. Phys. 42, 3656 (2003).
3) Y. Higurashi, T. Nakagawa, M. Kidera, T. Aihara, M.
Kase, and Y. Yano: Nucl. Instrum. Methods Phys. Res.
A 510, 206 (2003).
4) S. Gamino et al.: Rev. Sci. Instrum. 75, 1637 (2003).
5) T. Nakagawa and Y. Yano: Rev. Sci. Instrum. 71, 637(2000), and references therein.
6) O. Kamigaito et al.: Rev. Sci. Instrum. 70, 4523 (1999).

RIKEN Accel. Prog. Rep. 38 (2005)

Improvements in Hyper-ECR ion source for productionof metallic ions and extraction of ion beams
Y. Ohshiro,∗ S. Yamaka,∗ and S. Watanabe∗
A Hyper-ECR ion source1) and a 10 GHz ECRion source have been operated alternatively to supply
beams to the RIKEN AVF cyclotron. Various highly
charged gaseous ions are produced by the Hyper-ECR
ion source. Metallic ions are routinely produced by arod insertion method, which is adopted in the 10 GHz
ECR ion source. A solid material insertion system(called a rod insertion system) and a beam extraction
system (called an ion decelerator) were installed in theHyper-ECR ion source this year. With these devices,
metallic ion beams, for example, 24 Mg7+ and 7 Li2+
ion beams, were extracted from the Hyper-ECR ion
source, which enabled the supply of intense metallic
ion beams to a CRIB separator2) .
A schematic drawing of the rod insertion system inthe Hyper-ECR ion source is shown in Fig. 1. A rodshaped solid material is inserted near the ECR zone
on the right-hand side of the gas inlet. The solidmaterial was heated and ionized by hitting the ECR
plasma. The specifications of the rod insertion system
are shown in Table 1.
First, we inserted the rod into the ECR plasma andsubsequently heated the inside of the plasma chamber,for about 4 hours, to remove residual gases. Whenthe vacuum in the plasma chamber was of the order of
10−7 Torr, metallic ions were generated by the rod located 1.7 cm away from the boundary of the ECR zone.
The metallic ions 24 Mg7+ and 24 Mg5+ were producedby the 6-cm-long MgO rod. The metallic ion 7 Li2+ wasproduced by the 5-cm-long LiF rod.
The operating conditions of the ECR ion source areas follows: the supporting gas used for generating magnesium ions was oxygen and that for generating lithium
ones was helium. The RF (14.2 GHz) power was about
100 W. Two peaks of the mirror fields were 10.5 kG
and 11.5 kG. The length of the ECR zone was about
7 cm. The beam intensities obtained in the initial test
are summarized in Table 2.
For extraction, we replaced the extraction system of
the present electrode with the ion decelerator in order to increase the extraction voltage up to 20 kV, but
without changing the injection voltage.
Figure 2 shows the new ion decelerator consistingof electrodes arranged in the following order from theright-hand side: plasma, extraction, and ground electrodes. The gap between the plasma and extraction
electrodes is about 4.5 cm. Beams are supplied fromright to left.
We investigated the dependence of voltage on the
beam intensity at the extraction electrode, while thevoltage of the plasma electrode was 10 kV. In casesof 14 N6+ and 14 N5+ ions, the maximum beam intensity
was obtained at −5 kV (15 kV total acceleration) for
the 14 N6+ ion and −7 kV (17 kV total acceleration) for
the 14 N5+ ion on the extraction electrode. For ions, thebeam intensity increased roughly by a factor of two.
We completed the installation of the rod insertion
system and the ion decelerator in the Hyper-ECR ion
source. This enabled the extraction of metallic ion
beams from the Hyper-ECR ion source.
Table 2. Metallic beam intensities obtained in initial test.
Ion species
Beam intensity (eµA)

24

Mg7+
3

24

Mg5+
5

7

Li2+
10

Fig. 1. Rod insertion system in Hyper-ECR ion source.
Table 1. Specifications of rod insertion system.
Maximum rod cross section
Attachable rod length
Minimum speed
Maximum speed∗

Fig. 2. Ion decelerator of Hyper-ECR ion source.

2

0.16 cm
5 cm to 20 cm
0.1 mm/h
1.0 mm/hCenter for Nuclear Study, Graduate School of Science, University of Tokyo

References
1) Y. Ohshiro et al.: RIKEN Accel. Prog. Rep. 36, 279(2003).
2) Y. Yanagisawa et al.: RIKEN Accel. Prog. Rep. 34, 183(2001).

253

RIKEN Accel. Prog. Rep. 38 (2005)

A broadband cavity with magnetic alloy coresas buncher of ion beams†
M. Watanabe,∗1 Y. Chiba, T. Koseki, Y. Ohshiro,∗2 and S. Watanabe∗2
Presented in this paper is a broadband cavity thathas been installed in a beam transport line of an ion
source, HiECR, in the Center for Nuclear Study of The
University of Tokyo.
The HiECR ion source1) is intensively used for ion
source research and also used for R&D’s of ion beam
monitors, which are applicable to existing and future
cyclotrons in RIKEN. For the latter purpose, ion
beams having a bunched structure corresponding to
the frequencies of the cyclotrons are required. We havedeveloped a broadband and compact size cavity using
magnetic alloy (MA) cores as a buncher of HiECR ion
beams.
The cavity has a low Q-value less than 1 and operates in the wide frequency range between 18 and
45 MHz without any tuning systems. It is the ﬁrst MAloaded cavity used in a frequency higher than 18 MHz
in the world.
As one of the R&D’s of the RIBF project, we studied the characteristics of MA-loaded cavities in thefrequency range from 20 to 40 MHz.2,3) On the basisof such studies, we adopted the cut-core conﬁgurationof Finemet (FT-3M) for the buncher cavity. Finemet
is an iron-based nanocrystalline MA made by Hitachi
Metals, Ltd.4) The core is made of thin tape, whichis coated with SiO2 and wound into a toroidal shape.
The cut-core conﬁguration is cutting the troidal coreand setting it with appropriate air gaps between two
circular halves.5,6) Since the inductance of the cavity
depends on the air gap length of the cut core, the resonance frequency can be properly choosen with the gap
length.3)
Figure 1 shows a cross-sectional view of the buncher
cavity. To obtain a resonance frequency of approximately 30 MHz, the air gaps of the cut core are set tobe 0.5 mm. A Macor ring is attached to the acceleration gap for insulation. Because the present extraction
voltage of the HiECR ion source is 10 keV, two meshplates made of copper are placed in parallel at the acceleration gap to increase the transit time factor. Eachmesh is hexagonal and the distance between the centersof adjacent meshes is 2 mm. The width and thicknessof the mesh wires are 0.1 mm. The distance between
the mesh plates is 5 mm.
The rf characteristics of the cavity were measured using a network analyzer (HP4195A) with an
†
∗1
∗2

254

Condensed from the article in the Proc. 17th Int. Conf. on
Cyclotrons and Their Applications, Tokyo, 2004-10, in print.
J-PARC, Japan Atomic Energy Research InstituteCenter for Nuclear Study (CNS), Graduate School of Science, The University of Tokyo

Fig. 1. Cross-sectional view of the buncher cavity.

impedance test kit (HP41951A). The measured resonance frequency is 29.5 MHz. The measured Q-value,
shunt impedance Rs and inductance at the resonancefrequency are 0.7, 150 Ω and 0.7 µH, respectively. The
total gap capacitance including the parasitic capacitance is 40 pF at the resonance frequency.
We carried out a high-power test using a 3 kW rf
power ampliﬁer, which feeds the power to the cavity through a 50 Ω coaxial cable. To match the input
impedance of the cavity to 50 Ω, a capacitor of 200 pF
is connected in series with the cavity, and the cut cores
are set in parallel as shown in Fig. 1.
Figure 2 shows the frequency dependence of the input voltage standing wave ratio (VSWR). Input andreﬂection powers were measured using a vector volt-

Fig. 2. Frequency dependence of the voltage standing wave
ratio (VSWR) of the buncher cavity.

meter (HP8508A). The VSWR is kept at less than 1.3
in the frequency range from 20 to 45 MHz.
The relationship between the peak gap voltage V
and the cavity dissipation power P for several frequencies is shown in Fig. 3. The gap voltages were measured using a high-voltage probe (Tektronix, P5102).
Each curve shows the ﬁtted results of the square func-tion of the voltage. The calculated shunt impedance(Rs = V 2 /2P ) of the cavity is 133 Ω at 30 MHz.
The buncher cavity was installed in the beam transport line of the HiECR ion source system. Figure 4
shows a photograph of the cavity in the beam line.
The Finement cores were cooled by an electric fan.
Figure 5 shows the typical beam current waveform
observed using the buncher cavity. The beam current
was measured using a Faraday cup at 2.3 m downstream of the cavity. In this case, a 10 keV H+ beamwith an average current of 20 µA was used. The frequency and peak voltage of the cavity were 30 MHz and
150 V, respectively. As shown in the ﬁgure, a beam
structure of 30 MHz was successfully obtained.

Fig. 3. Relationship between the peak gap voltage and dissipation power of the buncher cavity.

Fig. 5. Typical bunched beam current waveform.

References
1) S. Watanabe et al.: CNS Rep. 45, 47 (2002).
2) M. Watanabe et al.: RIKEN Accel. Prog. Rep. 36, 325(2003).
3) M. Watanabe et al.: Nucl. Instrum. Methods Phys. Res.
A 532, 503 (2004).
4) Y. Yoshizawa et al.: J. Appl. Phys. 64, 6044 (1988).
5) M. Yoshii et al.: Proc. EPAC2000 (2000), p.984.
6) J. Dey et al.: Proc. PAC2001 (2001), p.882.
Fig. 4. Buncher cavity installed in the beam transport lineof the HiECR ion source.

255

RIKEN Accel. Prog. Rep. 38 (2005)

Status of control system for RARF and RIBF
M. Kobayashi-Komiyama, I. Yokoyama, M. Fujimaki, J. Odagiri,∗ and M. Kase
The structure of the current control system of
the RIKEN Accelerator Research Facility (RARF) isshown in Fig. 1. Our control system is based on
the Experimental Physics and Industrial Control System (EPICS),1) and we have been using the CAMACCIM/DIM system as a low-level control system for
more than 20 years. The basic operations of RARF
are currently carried out without any serious problems.
However, our control system includes one fundamental problem; a phototransceiver module in the U-Port
Adopter, which is an essential module in our CAMAC
system based on a CAMAC Serial HWY loop, is nolonger available. This means that it will be diﬃcult tocontinue using the current CAMAC-CIM/DIM system
when a U-Port Adopter is out of order.
To take measures to resolve the diﬃcult situation
to continue using our old CAMAC control system inthe future, we have applied two improvements to thecontrol system. One is the introduction of our original control device, Network-DIM (N-DIM). As mentioned in the last report,2) we have already started
to control nine sets of the new vacuum control unit
in RILAC using N-DIMs for the R/D of the N-DIM
system. This year, we increased the number of the
new vacuum control units in RARF up to approximately twenty. Furthermore, we replaced the control
system of the beam proﬁle monitor in RILAC fromthe CAMAC-CIM/DIM system with N-DIM. We developed an EPICS device support for a beam proﬁlemonitor control with a control group of KEK, and developed high-level control software based on it for the
CAMAC-CIM/DIM system on a Linux PC. Therefore,
an operator can control a beam proﬁle monitor as before, and the same type of graph can be obtained. Furthermore, we can obtain equal performance of beam
proﬁle measurement as before. Thus, there is no confusion during beam operation due to the diﬀerencein the type of controller. We have controlled about
twenty beam proﬁle monitors using N-DIM from thesame Linux server PC as the vacuum control since thissummer. Beam operation has been carried out without
any serious problems.
It is planned to replace the CAMAC-CIM/DIM system in RILAC with N-DIM gradually because thenumber of DIMs is small and we have a plan tosimplify the complex low-level control system of RILAC. However, it is diﬃcult to replace the entire
CAMAC-CIM/DIM system in RARF with N-DIM because of the following three reasons. One is that it
becomes too costly because there would be too many
DIMs in the RARF. We currently are using approximately 170 DIMs for RARF control. The second
reason is that RARF is in operation. The last reason is that the existing control commands in N-DIM
are prepared to control only beam diagnostic equipment such as a beam proﬁle monitor. Therefore, wehave to develop control commands when we replace the
CAMAC-CIM/DIM control system with N-DIM. This

Fig. 1. Structure of RARF control system.
∗

256

High Energy Accelerator Research Organization (KEK)is not easy. Thus, we investigated a way to support
the CAMAC-CIM/DIM system in the future, and decided to employ the Pipeline CAMAC Controller witha PC104plus Single-Board Computer, CC/NET,3) as
another improvement to maintain our old CAMACCIM/DIM system in RARF.
The important features of CC/NET are as following.
- CC/NET is a network-based intelligent controller.
- System disk: ﬂash disk (512 MB).
- OS: Debian/GNU Linux (kernel version 2.4).
- Includes original device driver and library.
According to the ﬁrst feature, we can replace the
CAMAC Serial HWY loop with the Ethernet using
CC/NET, and we can continue using the CIM/DIM
system in the future. More speciﬁcally, we can remove a U-Port Adopter and CAMAC Serial HWY loop
from our control system and control the CIM/DIM
system through the Ethernet directly from a highlevel control system using CC/NET instead of the former CAMAC crate controller. Furthermore, since Debian/GNU Linux is running on CC/NET, CC/NET
can also function as a high-level control system. We
developed the control software of CC/NET with thecontrol group of KEK as well as the N-DIM control
software. We derived it from the existing software camacLib.c, in EPICS R3.13, and developed a wrapper
over the CC/NET driver from TOYO to enable ISONE
Standard CAMAC APIs to be able to use our original
EPICS CAMAC-CIM/DIM device support modules aswell as the standard EPICS CAMAC device support

modules without major changes. There is no diﬀerence between the former CAMAC-CIM/DIM systemand the CC/NET-CIM/DIM system in terms of theoperator interface such as GUIs for beam operation.
Since the control system of RILAC is easy to renew because the number of components is small, we installed
CC/NET to run parallel to the installed N-DIM, andhave started to use it in the system since this spring,as shown in Fig. 1. The same control performance aswith the old system has been obtained to date.
As a next step, we have the following plans.
- Control Faraday cup by N-DIM.
- Replace the CAMAC-CIM/DIM system of AVF/
RRC, the other system in RARF, with the systemusing CC/NET.
For the ﬁrst plan, since we have already been able tocontrol the Faraday cup using a test GUI, we can proceed to develop the same type of control software as
the existing one as a next step. For the second plan, in
the CAMAC-CIM/DIM system of AVF/RRC including 6 sets of CAMAC crates, we are going to replace
the CAMAC crate controllers in use with CC/NET one
by one, while checking for eﬀects of radiation.
References
1) http://www.aps.anl.gov/epics/2) M. Kobayashi-Komiyama et al.: RIKEN Accel. Prog.
Rep. 37, 277 (2003).
3) http://www-online.kek.jp/˜yasu/Parallel-CAMAC/

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RIKEN Accel. Prog. Rep. 38 (2005)

Field test of N-DIM
M. Fujimaki, M. Kobayashi-Komiyama, and M. KaseIn the RIBF project, we have decided to use NDIM (Network Device Interface Module)1) as interface
circuits which control beam monitoring devices like a
Farady-Cup and beam proﬁle monitor, and also control vacuum pump sets installed along beam transportlines.
After a prototype of N-DIM circuit boards were
tested, twenty sets of N-DIM circuit boards were madein spring 2003. Then we started a ﬁeld test of NDIM to manipulate a vacuum pomp sets in RILAC(RIken Linear ACcelerator). In summer 2003, we installed twenty two N-DIM for vacuum pump set on
the beam transport lines of RILAC (Fig. 1). These
are remotely controlled by the host control system(EPICS)2) through Ether-net.
In spring 2004, we make 105 N-DIM which were
upgraded performance of analog circuits and clocklines on CPU board. In summer 2004, we replaced
CIM/DIM1) control devices for the beam proﬁle monitors with the N-DIM that we have been testing fromspring 2004 at the beam line for GARIS (Gas-ﬁlled
Recoil Ion Separator) at RILAC. In addition, we havealso installed a number of N-DIM to test the radiationeﬀect near the RRC (Riken Ring Cyclotron).
We consider that the N-DIM has controlled thebeam proﬁle monitors and vacuum pump sets nearlysatisfactorily, but their performance was not suﬃcientin hot environments. We have found that the network
interface chip on the CPU board of the N-DIM stopped
over about 45◦ C. N-DIM overheat when they are installed densely in a 19 inches standard cabinet at EIA(Electronic Industries Association). The case of NDIM is 1 U size of 19 inches standard cabinet at EIA,
which contains a 40 W power supply and an N-DIM
circuit board. The heat of this power supply causes
this problem. We avoid this problem by temporarily
using a large fun or installing N-DIM with an enoughcooling interval gap. We are currently developing a
cooling system that requires no maintenance. This situation is shown in Figs. 2 and 3.
When N-DIM is exposed to radiation, we feel that
the N-DIM is not better than the DIM (old control
device used before N-DIM). We have not made a measurement yet, but we have already observed the presence of some errors for N-DIM installed near the RRC.
We need to select the location of N-DIM consideringradiation level.
If a large number of N-DIM are connected to a network, it would causes a bad eﬀect on the network trafﬁc because each N-DIM transmits a large amount ofFig. 1. Vacuum control system.

Fig. 2. N-DIM for profile-monitors.

258

Fig. 3. N-DIM for profile-monitors.

data to the network once every 64 milliseconds during the measurement of a beam proﬁle. Therefore, wehave employed a fast network using optical ﬁbers. As
shown in Fig. 4, the network for N-DIM consists of one
optical HUB and six media converters.
Now we operate totally 42 N-DIM, twenty for beam
proﬁle monitors and twenty two for vacuum pump sets.
Faraday-cups are not controlled yet by N-DIM.
References
1) M. Fujimaki et al.: RIKEN Accel. Prog. Rep. 37, 279

Fig. 4. Network construction.

(2004).
2) M. Kobayashi-Komiyama et al.: RIKEN Accel. Prog.
Rep. 37, 277 (2004).

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RIKEN Accel. Prog. Rep. 38 (2005)

Remodeling of linear accelerator building for uranium acceleration
Y. Uwamino, N. Fukunishi, T. Nakagawa, M. Kidera, Y. Higurashi, H. Haba, S. Fujita,
E. Ikezawa, H. Sakamoto, S. Ito, M. Kase, and Y. Yano
For the RIBF Project, uranium acceleration is essential in obtaining unstable nuclei eﬃciently. However,uranium has not yet been accelerated in Japan, anda number of its technical aspects remain unexplored.
Therefore, it is necessary for us to master uranium acceleration in our present facilities. Actually, we areremodeling our facilities so that we can use uranium
in safety and in conformity to the requirements of laws
and regulations.
Because uranium is a nuclear fuel material, its use
is regulated by the Nuclear Reactor and Fuel Regulation Law, whereas radioisotopes other than nuclear
fuel materials must be used in conformity to the Law
Concerning Prevention of Radiation Hazards. The useof an accelerator is however regulated by the Law Concerning Prevention of Radiation Hazards. To gain regulatory approval to accelerate uranium, we must therefore meet all the conditions required by these two laws.
The Law Concerning Prevention of Radiation Hazards speciﬁes in detail the requirements concerning theequipment (e.g., draft), ﬂoor, walls and ceiling of laboratories where unsealed radioisotopes are used. On theother hand, the Nuclear Reactor and Fuel Regulation
Law is silent on these matters. However, because uranium emits highly hazardous α-rays, we decided thatthe rooms where uranium will be used should be designed and equipped in the same manner as the Class
1 radiation controlled area, which is an area in RIKEN
where unsealed radioisotopes are used.
There are two methods of introducing uranium into
an ion source: the slow supply of UF6 gas from an airtight container owing to vapor pressure at room temperature and the vaporization of a solid or powder uranium compound placed inside an ion source chamber.
At the Hot Lab of the Nishina Building, we will repacka small portion of UF6 from our stock into airtightcontainers. The solid or powder uranium compound
will be prepared at the Hot Lab for the chemical formula adjustment. Uranium will be handled at the Ion
Source Room of the Linear Accelerator Building andat the Hot Lab of the Nishina Building. This impels
us to prepare these two rooms accordingly.
At the Linear Accelerator Building, we partitioned
the Accelerator Room (Class 2 radiation controlledarea) to create the Ion Source Room (Class 1 radiation controlled room). We coated the ﬂoor and walls
to facilitate decontamination. Figure 1 shows the planof the new Ion Source Room. In area 1, we installeda ventilator equipped with HEPA ﬁlters. The exhaust
will be controlled by an α-dust monitor. We are currently planning to install a draft in area 1 for a simple
treatment of uranium. Area 2 houses ion sources. The

260

Fig. 1. Plan of Ion Source Room at Linear Accelerator
Building. In area 1, we installed a filter unit and an
exhaust fan. Area 2 houses two ion sources, whereas
area 3 is a contamination control room equipped with
an HFC monitor and sinks.

Ion Source Room will remain accessible even during
beam acceleration. Area 3 is the contamination control room equipped with access control devices. Access
control information can be monitored not only at the
Linear Accelerator Building but also at the Nishina
Building.
At the Hot Lab, we installed two new drafts thatwill be exclusively used to treat uranium (Fig. 2). At
the same time, two old drafts were replaced by new

Fig. 2. Plan of Hot Lab at Nishina Building. Gray-coloreddevices are four drafts (2 newly installed ones and 2
replacements ones). The uncolored draft has not been
replaced. We made an aeration hole covered with afilter on the entrance door to increase the ventilationrate.

ones. Because these four new drafts are equipped withscrubbers that can locally treat toxic gas or scattereduranium, exhaust from the draft chambers will be pu-

riﬁed by the HEPA ﬁlters of the ventilation system.
We increased the ventilation capacity due to the installation of new draft chambers.

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RIKEN Accel. Prog. Rep. 38 (2005)

Measurements of long-term phase stability of RRC rf-system
O. Kamigaito, N. Sakamoto, and Y. Chiba
The phase-control system of the RIKEN ring cyclotron (RRC: K = 540 MeV), based on a heterodyne technique, is designed to have a stability ofless than ±0.5 degrees in the rf-phase.1) In the RIbeam factory (RIBF) project, a better phase-stabilityof less than ±0.1 degrees is required since the RRC
will be used as the injector for a cascade of ring cyclotrons: ﬁxed-frequency ring cyclotron (fRC: K =510 MeV), intermediate-stage ring cyclotron (IRC:
K = 930 MeV), and superconducting ring cyclotron(SRC: K = 2500 MeV).2)
The long-term stability of the rf-phase has been measured with vector voltmeters (VVM), which had beencommercially available. However, the measurement accuracy is limited by the stability of the VVM itself;
it is very diﬃcult to achieve an accuracy better than±0.2 degrees in long-term measurements. On the other
hand, it has been reported that the phase detectors
using a hybrid coupler exhibit excellent characteristics.3,4) We fabricated a similar phase detector using a
180◦ hybrid coupler and measured the long-term stability of the RRC rf-system.
The circuit drawing is shown in Fig. 1.3) When rfsignals of the same frequency are applied to the input
ports of the 180◦ hybrid coupler, as shown in Fig. 1, theoutput voltage Vout of the op-amp is proportional toa · b · ∆φ, where a and b are the amplitudes of the input
signals, and the phase diﬀerence of the two signals is
assumed to be π/2 + ∆φ with |∆φ|  1.4) When theamplitudes are constant, the output voltage is sensitive
only to ∆φ.
It is important to maintain the temperature of thedetector circuit constant, because the circuit elements,
particularly the diodes, are sensitive to the temperature. Therefore, we housed the entire circuit in a smalloven, where the temperature is stabilized through asensor AD590.5)
Figure 2 shows the setup of the performance test

Fig. 1. Circuit drawing of phase detector.

262

Fig. 2. Setup for performance test of phase detector.

of the phase detector. Two rf-signals of 50 MHz with
10 dBm, divided from a single output of a signal generator, are fed into the input ports of the detector. In
one of the transmission lines, a phase shifter (coaxial
trombone) is inserted which varies the electric length
continuously and precisely. The total length of the line
is chosen so that the the phase diﬀerence of π/2 falls
into the stroke of the trombone. It was deduced fromthe measurement that the sensitivity to the phase difference is approximately 70 mV/degree for this input
level.
The oven temperature measured with a thermocouple and the output voltage were tracked from the startof the oven heating. The result shown in Fig. 3 indicates the stability of the phase detector.
With this detector, the rf-phase of the RRC resonator was measured at the rf-frequency of 36.66 MHz.
The reference signal from a synthesizer was fed into

Fig. 3. Output voltage and oven temperature measured
with thermocouple. The heater was switched on at theorigin of the horizontal scale in seconds. The output
voltage corresponding to the phase diﬀerence of 0.1 degrees is also indicated.

port 1, while the pick-up signal from the resonator was
fed into port 2. The electric length of the pick-up signal was adjusted using the trombone, so that the phase

diﬀerence was almost π/2. At the same time, both input signals were adjusted to be approximately 10 dBm,
and their amplitude variations were maintained within
10−3 during the measurements.
The result is shown in Fig. 4; it has been conﬁrmedthat the rf-phase is well controlled within less than±0.1 degrees for a long period.
The phase stability of the RIKEN heavy-ion linac
will be measured soon with the same detector. Further developments on the phase detector of this typeare required for the RIBF project, where severe rfphase control is required in the cascade operation of
the cyclotrons.
References

Fig. 4. Phase of the RRC rf-system No. 2 measured withthe phase detector (upper curve) and that with VVM(HP8508A/lower curve). The measurement with the
VVM shows a large drift in contrast with the upper
curve.

1) T. Fujisawa, K. Ogiwara, S. Kohara, Y. Oikawa, I.
Yokoyama, M. Nagase, and Y. Chiba: Nucl. Instrum.
Methods Phys. Res. A 292, 1 (1990).
2) Y. Yano, A. Goto, M. Kase, and T. Katayama: AIP
Conf. Proc. 600, 167 (2001).
3) E-mail from P. Sigg (PSI) to A. Goto, January 2001.
4) J. Cherix: TRIUMF Design Note, TRI-DN-86-17(1986).
5) Data sheet of AD590: http://www.analog.com.

263

RIKEN Accel. Prog. Rep. 38 (2005)

Rotating carbon disk stripper
H. Ryuto, S. Yokouchi, N. Fukunishi, H. Hasebe, N. Inabe, A. Goto, M. Kase, and Y. Yano
In the RIKEN RI-beam factory (RIBF), four stripper sections are under investigation. The stripper discussed here is the one referred to as the third stripper in Ref. 1. The third stripper is the last stripper the beam experiences before the beam is bombarded onto the target, when the ﬁxed-frequency ring
cyclotron (fRC) is employed. In the typical acceleration scheme under investigation, a 3 pµA 238 U72+
beam at 50.5 MeV/nucleon is stripped to 88+ by thethird stripper, a 14 mg/cm2 thick carbon plate. The
thickness of the third stripper was estimated using thetheoretical calculation code GLOBAL,2) and the extraction radius of the fRC was determined as the energy of the uranium beam behind the third stripper
which became 46 MeV/nucleon, the injection energyof the intermediate-stage ring cyclotron. The uranium
ion supplies approximately 8% of its kinetic energy to
the third stripper.3) Therefore, the power supplied by
the typical beam is expected to be 3 kW, which easily
evaporates a carbon plate placed in a vacuum chamber. To cope with such a high power supply, the carbon
plate is rotated, enlarging the area from which thermalradiation is emitted.
A thermal calculation for the carbon disk irradiatedwith a uranium beam was performed using a ﬁnite
element method code, ANSYS, by a method similar
to that in Ref. 4. In the calculation, a 3 pµA uranium beam was bombarded onto a 120-mm-diameter
14 mg/cm2 thick carbon disk rotating at 1000 rpm.
The uranium ion supplies its kinetic energy to thecarbon disk following a Bragg curve, and heats thedoughnut-shaped area of the rotating carbon disk. Theenergy supplied to the disk is mainly released as thermal radiation from the surface of the disk because of
the thinness of the disk, and a small amount of energy
is absorbed by the rotating shaft. The maximum temperature reached equilibrium after approximately 1 secof irradiation. Figure 1 shows the result of the calculation after approximately 3 sec of irradiation. The disk
was rotated clockwise. The beam was bombarded onto
the head part of the dark band at the left middle ofFig. 1. The maximum temperature was calculated to
be 1549◦ C, which was suﬃciently lower than the evaporation temperature of carbon.
Figure 2 shows the schematic of the rotating carbon disk stripper. A 120-mm-diameter carbon disk isplaced in a vacuum chamber that is connected to thebeam pipes. The disk is connected to an AC servo motor, whose maximum rotation frequency is 3000 rpm,
placed outside of the vacuum chamber by a watercooled ferroﬂuid-sealed rotary motion feedthrough.
The mechanism of disk rotation is the same as thatof liquid ﬁlm stripper in Ref. 5. The disk stripper

264

Fig. 1. Calculation of temperature increase of carbon disk
bombarded with 3 pµA uranium beam. This calculation
was performed using ANSYS.

Fig. 2. Schematic of rotating carbon disk stripper.

is designed such that the beam bombards the disk at
8 mm from its outer edge. An array of graphite plates
is soldered to a water-cooled copper plate close to thecarbon disk for the purpose of absorbing the thermalradiation emitted from the carbon disk. A sheet ofZnS (Ag) is placed at the position of the beam using a pneumatic linear motion feedthrough as a beam
viewer, and the beam spot on the sheet is observed using a TV camera placed outside the vacuum chamber
through a viewing port. Another viewing port facing
the beam spot on the carbon disk is prepared for athermal imaging camera.
The geometrical thickness distribution of the disk
was measured using a micrometer, and revealed thatthe thickness was uniform within 0.9%. Therefore, if
the density of the carbon disk is uniform, the energyof the uranium beam is expected to vibrate withinapproximately 0.07%, which is comparable to the energy straggling (one sigma) calculated using ATIMA
in LISE++6) of 0.03%. The angular straggling (onesigma) is expected to be 0.9 mrad.7)
A beam test was performed using a 0.1 pµA 86 Kr26+
beam at 46 MeV/nucleon accelerated by the RIKEN
heavy-ion linac and the RIKEN ring cyclotron withthe same acceleration scheme that is planned to be
used for a krypton beam in the RIBF. The krypton
beam was bombarded onto a 12 mg/cm2 thick carbon
disk rotating at 1000 rpm. The charge-stripped ionswere separated using a 90◦ bending dipole magnet according to the charge states, and the beam currents
were measured using a Faraday cup. The beam spot
on the beam viewer had an approximately sphericalshape, and the diameter was approximately 5 mm. The
power supplied to the carbon disk was approximately
18 W, which is much smaller than the expected power
supplied by the typical beam in the RIBF, a 3 pµA
uranium beam. A dim image of the beam shape on
the carbon disk was observed using a TV camera. No
visible damage to the carbon disk caused by the beam
test was observed.
Figure 3 shows the charge state fractions of 86 Kr
at 46 MeV/nucleon. The data for a 12 mg/cm2 thickcarbon disk rotating at 1000 rpm are plotted with thedata for carbon foils, aramid ﬁlms and a polyimide
ﬁlm. The results obtained using the GLOBAL code for
estimating the thickness of the third stripper are alsoplotted. These results well reproduced the data pointsof higher charge states, and naturally, the data points
for the rotating carbon disk also showed a consistenttendency with the other data points.
References
1) H. Ryuto, N. Inabe, N. Fukunishi, H. Hasebe, S.
Yokouchi, M. Kase, A. Goto, and Y. Yano: RIKEN
Accel. Prog. Rep. 37, 283 (2004).
2) C. Scheidenberger, Th. Stöhlker, W. E. Meyerhof, H.
Geissel, P. H. Mokler, and B. Blank: Nucl. Instrum.
Methods Phys. Res. B 142, 441 (1998).

Fig. 3. Charge state fractions of 86 Kr at 46 MeV/nucleon.
The horizontal axis indicates the thickness of the stripper and the vertical axis indicates the charge state fractions. The charge state fractions are normalized using
the sum of the measured charge state distributions. The
rightmost points are the data for the 12 mg/cm2 thickcarbon disk rotating at 1000 rpm. The other points are
the data for carbon foils, aramid films and a polyimide
film. Solid lines indicate the results obtained using the
GLOBAL code.

3) J. F. Ziegler, J. P. Biersack, and U. Littmark: The
Stopping and Range of Ions in Solids, vol. 1 (Pergamon,
New York, 1985).
4) A. Yoshida, K. Morita, K. Morimoto, D. Kaji, T. Kubo,
Y. Takahashi, A. Ozawa, and I. Tanihata: Nucl. Instrum. Methods Phys. Res. A 521, 65 (2004).
5) H. Ryuto, T. Chiba, H. Hasebe, M. Kase, and Y. Yano:
Jpn. J. Appl. Phys. 43, 7753 (2004).
6) D. Basin, O. Tarasov, M. Lewitowicz, and O. Sorlin:
Nucl. Instrum. Methods Phys. Res. A 482, 307 (2002).
7) R. Anne, J. Herault, R. Bimbot, H. Gauvin, G. Basin,
and F. Hubert: Nucl. Instrum. Methods Phys. Res. B
34, 295 (1988).

265

RIKEN Accel. Prog. Rep. 38 (2005)

Preparation of carbon foils by cracking using of methane gas
H. Hasebe,∗ H. Ryuto, M. Kase, and Y. Yano
Long-lived carbon stripper foils are strongly and urgently required for charge strippers of the RIKEN RIBeam Factory (RIBF) project. We have decided to
produce carbon foils (C-foils) ourselves because commercially available foils do not satisfy our requirements.
At the end of 1999, a high-vacuum evaporation system (EBX-2000C by ULVAC) was purchased and installed in the RILAC building. We started to produce
C-foils by an arc discharge evaporation method.1) We
successfully produced C-foils with a lifetime 120 times
longer than that of commercially available foils (Arizona Carbon Foil Co.).2)
For the further development of a long-life C-foil production, we started to use a chemical vapor deposition(CVD) apparatus with a methane (CH4 ) gas cracking
system from June 2004.
Figure 1 shows the CVD apparatus with the CH4
gas cracking system. It consists of a vacuum chamber,a cold-water supply system, a DC power supply systemfor ﬁlament heating, an oil-sealed pump for exhausting the chamber, a radiation thermometer for ﬁlament
temperature measurement, and a CH4 gas supply system. At the center of the chamber, a mount for theﬁlament, which is connected to the DC power supply
system via a vacuum feed through with a 38 mm2 cable, is located. Before the vacuum chamber is opened,
it is ﬁlled with N2 gas in order to avoid explosion anddamaging the C-foils.
As the ﬁlament, a tantalum plate with dimensionsof 26 mm × 76 mm × 0.1 mm was used for a preliminary
test. It was found that a C-foil with a thickness of
100–200 µg/cm2 was generated on the surface of theﬁlament heated at approximately 1200◦ C after it was
exposed to the CH4 gas with a pressure of 4000 Pa
for 20 min. The thickness of the C-foil was estimatedfrom the diﬀerence between the weights of the ﬁlament
before and after CVD.
Next, CVD was systematically investigated in nickel
ﬁlaments. Nickel plates of 26 mm × 76 mm with thicknesses of 0.05 mm, 0.08 mm and 0.1 mm were used asﬁlaments. The temperature of these ﬁlaments wasmaintained from 1100◦ C to 1200◦ C during CVD for as
long as 45 min. Figure 2 shows the thickness of the Cfoil as a function of CH4 gas pressure for the three different ﬁlaments. CVD starts at pressures higher than
200 Pa. The thickness of the C-foil gradually increases
for pressures 200–10000 Pa. The change is small forpressures higher than 10000 Pa.
The C-foil is separated from the Ni ﬁlament in asolution of chloride and nitric acid. It is very difﬁcult to separate a C-foil with a thickness less than
100 µg/cm2 , because it easily cracks. Thus, we could
not stick the foil on the holder. Figure 3 shows thephotograph of C-foils mounted on aluminum holders.

Fig. 2. Thickness of C-foil as a function of CH4 gas pressure
for three diﬀerent ﬁlaments.

Fig. 1. Photograph of the CVD apparatus with the CH4
gas cracking system.
∗

266

Katagiri Engineering Co., Ltd.

Fig. 3. Photograph of C-foils mounted on aluminum holders.

The right-hand side of the C-foil of 200 µg/cm2 thickness was formed by cracking, while its left-hand sideof 100 µg/cm2 thickness was formed by arc discharge
evaporation. The C-foil formed by cracking has metallic bright gloss, while that formed by arc discharge
evaporation has a blackish color.
The foils will be tested as charge strippers by intense heavy ion beam irradiation and their lifetimes
will be compared with those of the foils formed by othermethods.
References
1) H. Hasebe, I. Sugai, and M. Kase: RIKEN Accel. Prog.
Rep. 34, 313 (2001).
2) H. Hasebe, H. Ryuto, M. Kase, and Y. Yano: Proc. The
17th Int. Conf. on Cyclotrons and Their Applications,Tokyo, 2004-10, in press.

267

RIKEN Accel. Prog. Rep. 38 (2005)

Response of imaging plate and X-ray film to heavy-ion beamirradiation
H. Ryuto, T. Yamane,∗ S. Kubota,∗ N. Fukunishi, M. Kase, and Y. Yano
Imaging plates and X-ray films are utilized in various fields, e.g., biological research and nondestructive
inspection. To examine the possibility of using imaging
plates and X-ray films as detectors for beam diagnostics or radiation biology experiments in the RIKEN
Accelerator Research Facility (RARF), a neon beam
was bombarded on imaging plates and X-ray films.
The irradiation was performed at the E5B beam linein the RARF. An approximately 5-mm-diameter 20 Ne
beam at 133 MeV/nucleon was transformed into an approximately 10-cm-diameter uniform radiation field at
the target position of the automated irradiation system for radiation biology experiments1) by wobbler
magnets and a scatterer foil.2) The surface dose wascalibrated by an ionization chamber according to theprocedure described in Ref. 2. Because the range of the20
Ne beam at 133 MeV/nucleon in water is 25 mm,3)
which is much larger than the thicknesses of the imaging plates or X-ray films, the stopping power only
slightly changes while passing through the imaging
plates or the X-ray films. The dose rate was approximately 0.004 Gy/sec. A 0.5-mm-thick imaging plateor a 0.2-mm-thick X-ray film was placed on a movable table at the target position, and long and narrowleaves were placed on it for the purpose of simulating biological samples. The imaging plates used were
Fujifilm BAS-III, and the X-ray films, Fujifilm IX50
EPII or IX50 LP (with a lead sheet). The imaging
plates were scanned by a Fujifilm BAS2500 phosphor
imaging plate scanner. The uniformity of the beam
was examined by analyzing the image obtained by theimaging plate, revealing that the standard deviation of
the pixel density was 0.8%.
Figure 1 shows the pixel density of the imaging plateirradiated by a neon beam. The data show excellent
linearity. The response exceeded the dynamic range ofthe imaging plate when the imaging plate was irradiated with a surface dose of more than 0.016 Gy.
Figure 2 shows the optical density of the X-ray films
irradiated by a neon beam. Both data of the IX50 EPII
films and the IX50 LP films show linearity. The opticaldensity did not exceed the dynamic range of the X-ray
film when the film was irradiated with a surface doseof 2 Gy.
The pixel density of the imaging plate had an excellent linear dependence on the surface dose of neon
beam less than 0.008 Gy. The response exceeded the
dynamic range of the imaging plate when the dose wasmore than 0.016 Gy. Therefore, the imaging plate canbe a sensitive detector for use in a beam diagnostics∗

268

Fuji Photo Film Co., Ltd.

Fig. 1. Response of imaging plate to neon beam irradiation.
Horizontal and vertical axes show the surface dose andthe pixel density of the imaging plate, respectively.

Fig. 2. Response of X-ray film to neon beam irradiation.
Horizontal and vertical axes show the surface dose andthe optical density of the film, respectively. Circles indicate the data of IX50 EPII, and crosses indicate thedata of IX50 LP shielded by thin lead sheets.

or low-dose radiation biology experiment. The opticaldensity of the X-ray films had a linear dependence on
the surface dose of neon beam from 0.004 Gy to 2 Gy,
and still did not exceed the dynamic range, indicatingthat the X-ray films can be applied to a radiation biology experiment with a typical surface dose of 10 Gy.
References
1) H. Akiyoshi et al.: RIKEN Accel. Prog. Rep. 36, 291(2003).
2) T. Kanai et al.: RIKEN Accel. Prog. Rep. 25, 103(1991).
3) J. F. Ziegler et al.: The Stopping and Range of Ions in
Solids, vol. 1 (Pergamon, New York, 1985).

RIKEN Accel. Prog. Rep. 38 (2005)

Electrical power supply system for RI beam factoryT. Fujinawa, Y. Sekiguchi, A. Sakamoto,∗ H. Ikawa,∗ M. Kase, and Y. Yano
The RI Beam Factory (RIBF) has required a large
amount of electrical power after its commission. In
order to provide the necessary electrical power, the Gas
Insulated Substation (GIS), which is the No. 2 highvoltage substation in RIKEN, was constructed on the
Accelerator building roof in spring 2003 speciﬁcally forthe use of the RIBF. In this substation, 66 kV vacuum
circuit breakers (VCB) are used instead of gas circuit
breakers (GCB). The GIS uses VCBs, which requireless maintenance, space, and cost than GCBs.
At the same time, a medium-voltage metal-clad
Switch gear, which is called an alternative powersource, was provided in the bidding. A diagram ofthe electric power system for the RIBF as shown in
Fig. 1.

The No. 2 high-voltage substation is connected to
the No. 1 high-voltage substation located near theWest Gate by two 66 kV XLPE underground cables.
The cross–sectional area and length of the cables are
325 mm2 and 750 ms respectively. One is for normal
use and the other is for use as a spear. Each cable has
suﬃcient capacity for the expected volume increase in
the future.
The capacity of a 66/6.6 kV transformer was determined as 25 MVA. Its percent impedance (%TZ) was
selected as 11% (actual 10.67%) on the basis of voltage
regulation and the capacity of the cogeneration system(CGS).1)
The rating of each VCB in 6.6 kV lines was determined as 25 kA from the short-circuit current. The

Fig. 1. Single-line diagram of electrical power supply system for RIBF.
∗

Mitsubishi Electric.

269

short-circuit current in the medium-voltage system iscalculated as follows.
The impedance map is shown in Fig. 2.
The %TZ at 10 MVA base is
10000
× 10.67 = 4.268,
25000∴ %ZT = 4.268 (at 10 MV),%ZT =The total percent impedance (%Z) of the power sourcefrom the load side is%Z =(0.7167 + 0.0093 + 4.268) × 17.85= 3.90(0.7167 + 0.0093 + 4.268) + 17.85

at 10 MVA,
There for the short-circuit current (IF) is√
IF = Capacity(10 MVA)/ 3
× voltage (kV) × 100/%Z,
100
10000
= 22.43 kA,
×
IF = √
3 × 6.6 3.90
The maximum permissible short-circuit current of a
60 mm2 cable is
Is = (3.4 × 60/0.00393 × 0.309 × 0.125 loge 180)1/2= 25.26 (kA); 25.26 > 22.43 (kA).
Here 3.4 is the speciﬁc heat of copper (J/cm3 /◦ C),
60 is the cross-sectional area of the conductor (mm2 ),0.00393 is the temperature coeﬃcient of copper, 0.309
is the alternative resistance (Ω/cm at 20◦ C), 0.125 is
fault duration (sec) and 180 is the temperature increase from 54.42 to 230◦ C (conductor temperaturein the nominal current: 54.2◦ C, short time permissible
temperature of XLPE: 230◦ C).

The CGS system is separated within 20 msec with ahigh-speed breaker (52SRB2), as shown in Fig. 1, when
the commercial power supply suddenly stops. Then,the CGS only supports essential loads such as the cryogenic system and superconducting magnets and works
as a 5 MW UPS.
A current-limiting reactor with a capacity of 9 MVA
was installed in the line to the existing facility (RARF)
because the capacity of each circuit breaker (VCB) in
the RARF substation is 13.8 kA and thus they cannot
withstand a short-circuit current of 22.84 kA.
The newly constructed switch gear with a capacityof 20 MW is of a metal-clad type according to the JEM(Japan Electrical Manufacturers) standard and is very
compact. Its volume is almost the same as that of the
RARF 7 MW cubicles. This M/C can be operated in a
power outage because the DC power supply is used for
its control. This feature makes the M/C much safer
than existing cubicles.
The DC power source used for the accelerators produces undesirable harmonic currents. To prevent thisfrom happing, two transformers with the - and Y connections were used for the IRC and others asshown in Fig. 1. This makes same eﬀect as multi phaserectiﬁers. Since transformers are placed inside of abuilding, dry-type ones are used. The dry-type transformers require no insulation oil; therefore, they satisfy
the Fire Defense Law. In addition, all transformers in
the experimental building are highly eﬃcient and meetthe law concerning the Rational Use of Energy Policy.
In the RIBF, more than 50 electrical motors are installed, including four 315 kW cryogenic system compressors. All motor starters are direct connection typewhich enables a quick start and an eﬃcient restart.
Also, they are more reliable and economical than Y-
and/or reactor starters. The direct-type starters canonly be used when the transformer’s capacity is suﬃciently large.
The amount of equipment for the experimentalbuilding will be increased in the future, and more
power will be required. The space for the 2nd bankhas been prepared for the expansion.
Reference
1) T. Fujinawa et al.: RIKEN Accel. Prog. Rep. 36, 310(2003).

Fig. 2. Impedance map.

270

RIKEN Accel. Prog. Rep. 38 (2005)

Cooling water system in RIKEN RI beam factory
T. Kageyama, N. Inabe, M. Kase, and Y. Yano
A cooling water system for the RIBF1) has been
completed in the RIBF building. This cooling system
is used for removing heat originating from sources suchas magnets, RF systems, power supplies, liquid He systems and the vacuum systems of accelerators (IRC2)
and SRC3) ), beam transport lines and the BigRIPS.4)
Moreover, the cooling water plays an important rolein the stable operation of the above-mentioned devices
by maintaining the temperature of the cooling water
constant.
Figure 1 shows a ﬂowchart of the cooling water system. As shown in Fig. 1, the cooling system is divided
into two stages by heat exchangers to prevent cooling water used in rooms where radiation is generated
from ﬂowing out of the radiation control area. The
ﬁrst stage consists of closed-loop channels between theheat sources and heat exchangers. In each channel,
electrical pure water (> 1 MΩ cm) is supplied for insulation of the heat sources. The second stage consistsof channels between the heat exchangers and cooling
towers or headers of cold water sent from refrigerators.
In terms of the quality (temperature, pressure, and soon) of supplied water, the ﬁrst and second stages are
separated into eight branches and four branches, respectively. As shown in Fig. 1, one branch with noheat exchanger also exists in the cooling system.

In Table 1, the heat removal conditions of eachbranch are summarized. As shown in Table 1, ﬁne temperature control is required for the branches of the IRC
trim, IRC main and SRC trim. The average temperature of the inlet and outlet ismaintained at 30 ± 0.1◦ C
for the IRC trim and IRC main and 30 ± 0.5◦ C for
the SRC trim even if the consumption power of themagnet changes. The middle-temperature branch removes heat from the vacuum pumps of the IRC andthe SRC and the liquid He system for the quadrupolesin the BigRIPS. This branch requires cooling water of
low temperature (< 30◦ C at inlet) and low pressure(< 0.7 MPa). The low-temperature branch supplies
cold water of 20◦ C to the magnetic channels of the SRC
with a large temperature increase and magnets andtarget of the BigRIPS to prevent the room temperaturefrom rising. The low-pressure branch supplies cooling water of 0.6 MPa to the ampliﬁers of RF systems
in the IRC and SRC. The room-temperature-1 androom-temperature-2 branches supply a large amountof cooling water at room temperature to the magnets
and power supplies of the IRC, the SRC, beam transport lines and the BigRIPS.
The branches of the second stage connect with thoseof the ﬁrst stage according to the temperature of supplied water. The CR1 and CR2 can supply cold wa-

Fig. 1. Flow chart of cooling water system in RIBF.

271

Table 1. Heat removal conditions of each branch.
Branch(1 st stage)
IRC trim
IRC main
SRC trim
Middletemperature
Lowtemperature
Lowpressure
Roomtemperature-1
Roomtemperature-2(2nd stage)
CR1
CR2
CT2
CT3
(other)CT4

Heat
Flow Pressure Temperature(kW) (l/min) (Mpa)
(◦ C)
150
370
780
520

350
550
670
1100

1
1
1
0.7

30 ± 0.1
30 ± 0.1
30 ± 0.5
< 30

2450

4100

1

< 20

600

1450

0.6

30∼35

3030

4500

1

30∼35

3840

5580

1

30∼35

1300
2970
600
6870

1750
5280
1450
10160

0.35
0.38

7
7
30∼35
30∼35

1370

4220

0.4

30∼35

ter at approximately 7◦ C all year. The CR1 connectswith the three branches of the IRC trim, IRC mainand SRC trim. The CR2 connects with branches of
middle- and low-temperature. The CT2 (1500 kW)
and CT3 (8000 kW) have cooling towers and connect
with the low-pressure and the room-temperature-1 androom-temperature-2 branches, respectively. The CT4(1500 kW) directly connects with the liquid He systemsof the SRC and BigRIPS with no heat exchanger. The
channels of the CT2 and CT4 are of closed-loop typewhile that of the CT3 is not because the CT3 is acooling tower of open-air type.
The cooling system has two bypasses for backup incase of emergency or maintenance because the liquid
He system cannot be stopped anytime during the year.
One is used to exchange the CT4 for the CT3 andanother to exchange the middle-temperature branch
for the SRC trim branch.
Almost all the devices, such as pumps, heat exchangers and buﬀer tanks in the cooling system are locatedon the ﬁrst ﬂoor and connected to heat sources underground by pipes for pure water. Headers and pumps
in the CR1 and CR2 are also located on the ﬁrst ﬂoor
connected by pipes with heat insulators.
Cooling towers and pumps in CT2, CT3 and CT4
are located on the roof and are connected to heat exchangers or heat sources on the ﬁrst ﬂoor.
Pumps are installed in all branches with consideration of the amount of water ﬂow and pressure.

272

The ﬁrst-stage pumps are for pure water. The CT2,
CT3, CT4 have one additional pump for backup. The
middle-temperature branch also has a backup pump
since the liquid He system cannot be stopped. Buﬀer(expansion) tanks are installed in all closed-loop channels to absorb the change in water volume due to temperature. Filters to produce pure water are installed in
all the branches of the ﬁrst stage. To locate ﬁlters, eachbranch has a small loop separated from main channel.
Heat exchangers are installed not only at boundary between the ﬁrst and second stages but also in the lowtemperature and room-temperature branches as shownin Fig. 1. The reason why there are three additional
heat exchangers located in the ﬁrst stage is that cooling water passes through heat sources with very strong
radiation. These heat exchangers are located near heatsources. Three-directional valves are installed nearheat exchangers in the second stage for temperature
control. In branches needing ﬁne temperature control (IRC trim and main), heaters are installed in theﬁrst stage. Temperature is automatically controlled
by a loop composed of the three-directional valve, theheater and thermometers. Constant ﬂow valves areequipped for the branch with additional limbs so as tomaintain constant ﬂow even if the operation of otherlimbs is changed. Flowmeters, pressure gauges, andthermometers are installed in all branches. Ohmmeters are also installed in all branches of the ﬁrst stage.
A PC monitor is installed to allow the observation of
the cooling system status and to enable the switching on/oﬀ of pumps, cooling towers and certain valves.
Exchange of backup can also be carried out from thePC.
We examined the system by bypassing with U pipes
at connecting points to heat sources and conﬁrmedthat the amount of water ﬂow and pressure required ineach branch were realized. A check of the loop for temperature control was also performed. At present, theCT4, IRC trim and IRC main branches and a partof CR1, CR2, CT3, middle-temperature and roomtemperature-1 branches have already been used. Nearfuture ﬁne temperature control will be checked using
heat sources of the IRC trim and main branches.
References
1) Y. Yano: Proc. 17th Int. Conf. Cyclotrons and Their
Applications, Tokyo, 2004-10, to be published.
2) J. Ohnishi et al.: Proc. 17th Int. Conf. Cyclotrons andTheir Applications, Tokyo, 2004-10, to be published.
3) H. Okuno et al.: Proc. 17th Int. Conf. Cyclotrons andTheir Applications, Tokyo, 2004-10, to be published.
4) T. Kubo: Nucl. Instrum. Methods Phys. Res. B 204,
97 (2003).

RIKEN Accel. Prog. Rep. 38 (2005)

Improvements of a current and position monitor using HTS SQUIDs
aiming at the measurements of a 1 nA DC beam
T. Watanabe, M. Kase, Y. Sasaki,∗1 S. Watanabe,∗2 T. Ikeda, T. Kawaguchi,∗3 and Y. Yano
A highly sensitive current and position monitor withHTS (High-Temperature Superconducting) SQUIDs(Superconducting QUantum Interference Device) andan HTS magnetic shield for the measurement of theintensity of faint heavy ion beams was developed for
the RIKEN RI beam factory project.1–7) We abbreviate this monitor to “SQUID monitor” here. The HTS
magnetic shield and the HTS current sensor including
the HTS SQUID8) are cooled by a low-vibration pulsetube refrigerator. Both the HTS magnetic shield andthe HTS current sensor were fabricated by dip-coatinga thin Bi2 -Sr2 -Ca2 -Cu3 -Ox (Bi-2223) layer on 99.9%
MgO ceramic substrates. The HTS technology enabled
us to develop a system equipped with a downsized andhighly sensitive current monitor. Recently, a prototype system was completed and installed in the beamtransport line of the RIKEN Ring Cyclotron for themeasurement of the DC- current of high-energy heavyion beams. As a result, we succeeded in measuring theintensity of the 600 nA 40 Ar17+ beam (95 MeV/u).
The purposes of the SQUID monitor are an accurate
and nondestructive measurement of the current andposition of the DC beam. This monitor is expected to
be used for the high-energy heavy-ion beam, because if
the beam were stopped by a destructive monitor suchas a Faraday cup, the beam could no longer be used,
and there would be a danger of activation and melting which could be caused by a miss-handling operation. Also, we are currently studying how to use thismonitor for ion implantation in semiconductor production, particularly the nondestructive and real time dose
measurements of drift and discharge caused by an ion
source. In this paper, we report the progress of the
SQUID monitor used as a position monitor and the research towards improving the resolution by more than
two orders of magnitude.
We investigated whether the principle of a conventional beam position monitor could be applied to the
SQUID monitor. The beam position pick up has a pairof isolated electrodes (or two pairs, if two beam position coordinates are being measured). The deviationof the beam center with respect to the vacuum chamber can be monitored by measuring the diﬀerence involtage of each electrode induced by the beam.9) Then
we fabricated a smaller version of the position sensor,
as shown in Fig. 1 (a). The HTS current sensor is divided into two parts by the slit and setting an HTSSQUID on each bridge. To measure the position de∗1
∗2
∗3Matsushita Electric Industrial
Center for Nuclear Study, Graduate School of Science, University of Tokyo
KT Science Ltd.

Fig. 1. (a) Smaller version of position sensor which is divided into two parts by the slit; a SQUID is set on eachbridge. (b) Position measurement system which is composed of an X-Y stage driven by stepping motors, and a
Cu-rod which is ﬁxed on the X-Y stage and which plays
the role of a simulated beam.

pendence on the output voltage of each SQUID, weconverted a measurement system which was used tomeasure the ﬁeld distribution inside an HTS magnetic
shield10) into the position measurement system. Thissystem is composed of an X-Y stage driven by stepping
motors, and a Cu-rod which is ﬁxed on the X-Y stage
and simulates a beam. Figure 2 shows the schematic
drawing of the position sensor, where D is the widthof the sensor, ∆x is the beam position from the center, and VR and VL represent the output voltage oneach SQUID. If the position of the beam is center, theoutput of each SQUID should be equal. However, if
the beam is shifted to the right-hand side, it is to be
expected that the output signal VR will be larger thanthat of VL . Usually, a beam position ∆x is obtainedby the following relationship:∆x =1 D VR − VL
1D∆
=
,
ε 2 Σ
ε 2 VR + VL

where ε is the position sensitivity of the monitor. The
measured values of ∆/Σ are plotted versus the Cu-rod
position in Fig. 3 where a sine of simulated current(1 mA, 5 Hz) was used, and thus we discovered thatthe beam position and the beam current can be measured simultaneously in real time by dividing the current sensor into two parts and setting a SQUID on eachFig. 2. Schematic drawing of the current sensor of the HTSSQUID monitor.

273

Fig. 3. Measured values of ∆/Σ are plotted versus the wire
position where a sine of simulated current (1 mA, 5 Hz)
was used.

bridge. The output voltage on the right SQUID VR is
not equal to that on the left SQUID VL when the position of the simulated beam is center in Fig. 3 because
the output voltage of the SQUID is very sensitive tothe setting accuracy, but it was diﬃcult to install each
SQUID on the bridge accurately because each SQUID
was bound by two stainless bands (Fig. 1).
Next, we describe the research to improve the current resolution. Although we can measure the intensity of the sub-microampere beam, a current resolution that is higher by more than two orders of magnitude is required. Therefore, we are now attempting
to improve the bridge of the current (position) sensor (Fig. 4). The principle of the SQUID monitor isbased on the cryogenic current comparator. The MgOceramic tube used as the substrate is coated on bothsides with a thin layer of Bi2223. While a beam is passing through the tube, a shielding current produced by
the Meissner eﬀect ﬂows in the opposite direction along
the wall, so as to screen the magnetic ﬁeld generated
by the beam (Fig. 4 (a)). Because the outer surface
is designed to have a bridge circuit, the current concentrates in the bridge circuit and forms an azimuthal
magnetic ﬁeld Φ. The HTS SQUID is located close to
the bridge circuit and can detect the azimuthal magnetic ﬁeld. Figure 4 (b) shows the close view of the
improved bridge circuit. The high-permeability material is placed into the hole in the bridge (c) and an
HTS SQUID with a high-permeability core is placedon the bridge circuit (d). Finally, both materials are

Fig. 4. Schematic drawing of the improved bridge of thecurrent (position) sensor.

274

ﬁxed by this high-permeability cylinder (e). The magnetic ﬁeld generated by the beam is covered by thehigh-permeability materials completely. In addition,
because the ridge circuit must be fabricated precisely,
the substrate made of MgO is changed to one madeof silver (Ag). Figure 5 shows a comparison of enlargements of surfaces of HTS material between Bi2223
coated on the MgO substrate (a) and Bi 2212 coated on
the Ag substrate (b). These pictures were observed using a EPMA (Electron Probe (X-ray) Micro Analyzer)
in RIKEN and clearly showed that the surface of the
HTS material Bi2212 was smooth and the Bi2212 wasadhered strongly on the Ag substrate compared with
the Bi2223. Finally, the calculation of the static magnetic ﬁeld by the MAFIA program showed a 1000-foldimprovement because the coupling eﬃciency of transferral of the magnetic ﬁeld produced by the beams toa SQUID can be improved. We aim to measure thebeam current and position of a 1 nA beam to render
the system applicable to physics and biology experiments as well as to an ion implanter. The authors
are grateful to R. L. Fagaly of Tristan Technologies forvaluable insights into the HTS SQUID system and to
K. Watanabe of RIKEN for the support and advice
regarding the EPMA.

Fig. 5. Comparison of enlargements surfaces of HTS material between Bi2223 coated on the MgO substrate (a)and Bi 2212 coated on the Ag substrate (b).

References
1) T. Watanabe et al.: RIKEN Accel. Prog. Rep. 35, 314(2002).
2) T. Watanabe et al.: Proc. 8th European Particle
Accelerator Conf., Paris, France, 2002-6 (EPS-IGA,
2002), p. 1995.
3) T. Watanabe et al.: RIKEN Accel. Prog. Rep. 36, 331(2003).
4) T. Watanabe et al.: CNS Annu. Rep. 59, 71 (2003).
5) T. Watanabe et al.: Proc. 14th Symp. on Accelerator Science and Technology, Tsukuba, 2003-11 (KEK,2003), p. 99.
6) T. Watanabe et al.: RIKEN Accel. Prog. Rep. 37, 310(2004).
7) T. Watanabe et al.: Supercond. Sci. Technol. 17, S450
(2004).
8) M. I. Faley et al.: IEEE Trans. Appl. Supercond.
(ASC2000) 11, 1383 (2001).
9) T. Watanabe et al.: Nucl. Instrum. Methods Phys.
Res. A 336, 194 (1996).
10) S. Watanabe et al.: Proc. 8th European Particle Accelerator Conf., Paris, France, 2002-6 (EPS-IGA, 2002),
p. 1992.

RIKEN Accel. Prog. Rep. 38 (2005)

Beam quality estimation of RIBF accelerator complex
N. Fukunishi, A. Goto, O. Kamigaito, M. Kase, H. Ryuto, N. Sakamoto, M. Wakasugi, R. Taki,∗ and Y. Yano
Beam qualities in the RIKEN RI Beam Factory1)(RIBF) were estimated based on the measured longitudinal emittance of beams accelerated by the RIKEN
Ring Cyclotron.2) The RIBF is a project to upgrade the present RIKEN Accelerator Research Facility (RARF) and is aimed at producing the world’s
most intense RI beams. The accelerator complex usedin the RIBF consists of three existing accelerators andthree new ring cyclotrons. The existing three accelerators are the RIKEN Linear Accelerator (RILAC), an
AVF-type cyclotron (AVF) and the RIKEN Ring Cyclotron (RRC). The three new ring cyclotrons underconstruction are a ﬁxed-frequency Ring Cyclotron3)(fRC), an Intermediate-stage Ring Cyclotron4) (IRC)
and a Superconducting Ring Cyclotron5) (SRC). Three
acceleration modes will be available in the RIBF. The
ﬁrst mode involves the use of ﬁve accelerators in series: the RILAC, the RRC, the fRC, the IRC and the
SRC. In this mode, every element from hydrogen touranium can be accelerated up to 350 MeV/nucleon.
However, the beam energy will be ﬁxed because thefRC is a ﬁxed-frequency machine. The second is avariable-energy mode involving four frequency-variable
accelerators, i.e., the RILAC, the RRC, the IRC andthe SRC. This acceleration mode will be able to produce, for example, a 400 MeV/nucleon 40 Ca beam anda 350 MeV/nucleon 86 Kr beam. The last mode is
aimed at producing an 880 MeV polarized deuteronbeam. The accelerators employed here are the AVF,
the RRC and the SRC. Beam quality estimations were
performed for the ﬁrst two modes. Details are shown
in Ref. 6.
A series of longitudinal emittance measurements
were performed using the high-resolution magnetic
spectrometer SMART placed in the E4 experimental
vault in the RARF.2) An example of measured longitudinal phase space distributions is shown in Fig. 1
for a 95 MeV/u 40 Ar17+ beam. The energy spreadand the time spread of the beam were determined tobe 1.3 × 10−3 (FWHM) and 700 ps (FWHM), respectively. Based on the measured longitudinal emittanceshown in Fig. 1, longitudinal phase space distributions
were estimated at every stage of the RIBF from theextraction point of the RRC to the injection point of
the SRC. The transverse emittance at the injection
point of the RRC was chosen to be 16π mm mrad.
In the simulations, we neglected the imperfections ofisochronous ﬁelds, instabilities of the power supplies
of magnets, instabilities of the RF acceleration sys∗

Department of Accelerator Science, School of High Energy
Accelerator Science, The Graduate University for Advanced
StudiesFig. 1. Measured longitudinal phase space distributions at
the extraction point of the RRC for a 95 MeV/nucleon
40
Ar beam. The vertical axis shows the relative deviation of the kinetic energy (E) and the horizontal axis
shows the extraction time of each particle.

tems and other eﬀects originating from poor tunings inenergy matching, dispersion matching and transverse
emittance matching when injecting a beam into the cyclotrons. We investigated these eﬀects and found thatthey did not seriously deteriorate beam qualities when
accelerators were carefully tuned. We also did not include the space-charge eﬀects in these simulations. The
space-charge eﬀects become serious, for example, in thecase of a 350 MeV/nucleon 1 pµA 238 U88+ beam, as reported in Ref. 7. Hence, the present results hold forthe low-intensity (< 0.1 pµA) cases.
We chose a 350 MeV/nucleon 86 Kr beam as an example of the variable-energy mode. Ions extracted fromthe RRC will be injected directly into the IRC, which is
114 meters away from the RRC. The long drift space
between the RRC and the IRC will expand a beam
bunch markedly. However, the IRC, which has a ﬂattopping acceleration system, can accept almost all theions transferred to it. The SRC will further accelerate
the IRC beam. The longitudinal phase space distribution estimated at the injection point of the SRC isshown in Fig. 2. The longitudinal emittance is sufﬁciently small compared with the longitudinal acceptance of the SRC, as shown in Fig. 2. High-quality
beams are expected after acceleration by the SRC.
A 350 MeV/nucleon 136 Xe beam was chosen as an
example of the ﬁxed-energy mode. In this mode, ionsaccelerated by the RRC will be transferred to the fRC
through a beam rebuncher to be installed in the RIBF
and further accelerated by the remaining three cy-275

Fig. 2. Longitudinal phase space distribution at the injection point of the SRC for 86 Kr beam accelerated in thevariable energy mode. The box shows the acceptanceof the SRC.

clotrons. As shown in Fig. 3, a beam rebunching system between the RRC and the fRC is essential because
the operating frequency of the RF system in the fRC
is chosen to be three times that of the RRC. The fRC
cannot accept beams accelerated by the RRC without a rebuncher. The distance between the fRC andthe IRC is more than 140 meters, therefore we should
widen the phase acceptance of the IRC to 30 degrees
by increasing the operating voltage of the ﬂat-topping
cavity. The phase space distribution expected at the
injection point of the SRC is shown in Fig. 4 with the
SRC acceptance. We also expect fairly good beam
qualities.
Beam quality after acceleration by the RRC depends
on the injector. The AVF cyclotron was employed forthe 95 MeV/nucleon 40 Ar beam, the longitudinal emittance of which was used for input data in the simulations. In contrast, the RILAC will mainly be used as

Fig. 3. Longitudinal phase space distribution for 136 Xe at
the extraction point of the fRC (a) with and (b) withouta rebuncher.

276

Fig. 4. Longitudinal phase space distribution for 136 Xe in
the fixed-energy mode. The box in the figure shows theacceptance.

the injector in the RIBF. We also compared the measured longitudinal emittance of the 95 MeV/nucleon
40
Ar beam with the results of a numerical simulation.
We found that the measured emittance was larger thanthat given by the simulation under the assumptionthat the momentum and phase spreads at the injection point of the RRC were 0.3% (FWHM) and ± 9
degrees (2σ), respectively. One possible explanation
for the discrepancy is that the momentum spread at
the injection point of the RRC was much larger thanthat assumed. To eliminate the discrepancy and understand the injector dependence, we plan to measure
the longitudinal emittance of RILAC beams before andafter acceleration by the RRC.
References
1) Y. Yano et al.: Proc. 17th Int. Conf. on Cyclotrons andTheir Applications, Tokyo, 2004–10, to be published.
2) R. Taki: Master Thesis of Michigan State University(2003).
3) N. Inabe et al.: 17th Int. Conf. on Cyclotrons andTheir Applications, Tokyo, 2004–10, to be published;
T. Mitsumoto et al.: 17th Int. Conf. on Cyclotrons andTheir Applications, Tokyo, 2004–10, to be published.
4) J. Ohnishi et al.: 17th Int. Conf. on Cyclotrons andTheir Appilications, Tokyo, 2004–10, to be published.
5) H. Okuno et al.: 17th Int. Conf. on Cyclotrons andTheir Applications, Tokyo, 2004–10, to be published.
6) N. Fukunishi et al.: 17th Int. Conf. on Cyclotrons andTheir Applications, Tokyo, 2004–10, to be published.
7) S. B. Vorojtsov, A. S. Vorozhtsov, T. Mitsumoto, A.
Goto, and Y. Yano: RIKEN-AF-AC-36 (2002).

RIKEN Accel. Prog. Rep. 38 (2005)

Status of fixed-frequency Ring Cyclotron (fRC) in RIBF
N. Inabe N. Fukunishi A. Goto M. Kase H. Ryuto N. Sakamoto S. Yokouchi T. Mitsumoto,∗ and Y. Yano
A ﬁxed-frequency Ring Cyclotron is used as abooster to obtain very heavy ions (> Xe) of 350 MeV/uwith a high intensity in the RIBF.1) Figure 1 shows anacceleration scheme in the RIBF. As shown in Fig. 1,
middle heavy ions (< Xe) are stripped to high-charge
states by a charge stripper2) upstream of the RRC andaccelerated up to 46.3 MeV/u by the RRC to be sent
into the IRC directly. In the case of very heavy ions(> Xe), however, a high-intensity beam cannot be expected in the above-mentioned acceleration scheme because eﬃciency to produce the required high-charge
state using the charge stripper is very small due tothe low beam energy. For this reason very heavy ionsare accelerated up to 11 MeV/u by the RRC without using the stripper upstream of the RRC and areboosted up by the fRC after passing through a charge
stripper downstream of the RRC in order to obtain
suﬃcient energy for acceleration by the IRC. Thesebeams are then sent to the IRC via a charge stripper
again. In the case of the U ion beam as illustrated
in Fig. 1, 238 U35+ obtained from an 18 GHz ECR ion
source is accelerated up to 11 MeV/u by the RRC andboosted up to 50.7 MeV/u by the fRC and 115 MeV/u
by the IRC after charge-stripping to each favourable
charge state at the charge strippers upstream of each
cyclotron. Furthermore, this beam is also accelerated
up to 350 MeV/u by the SRC. The charge states in
the fRC and IRC are 71+ and 88+, and the expected
fractions are 1/5 and 1/3, respectively.
The fRC is a four-sector ring cyclotron operated at aﬁxed frequency unlike other cyclotrons in the RIBF toreduce the construction cost. Moreover, to make thecorrection of magnetic ﬁeld small, only ion beams withvery similar charge-to-mass ratios can be accelerated.
The main speciﬁcations of the fRC are summarizedin Table 1. The injection and extraction energies (11.0
and 50.7 MeV/u) of the fRC are determined by considering the energy losses in the charge strippers upstream and downstream of the fRC. The K-value ofthe fRC is 570, which corresponds to an accelerationof 50.7 MeV/u for 238 U71+ . The frequency of the fRC
is determined as 55 MHz, which is three times those

Table 1. Specifications of fRC.
K Value
Energy (MeV/u)
Injection
Extraction
Frequency (MHz)Harmonics
Radius (m)Injection
Extraction
No. of sectors
Sector angle (degrees)
Max. magnetic field (T)Acceleration voltage (MV/turn)Phase acceptance (degrees)

570
10.5
50.7
55
12
1.55
3.30
4
58
1.68
0.7–1
±10

of the RILAC and the RRC, so as to obtain a highvoltage in the main RF cavity that is small with a low
power. The harmonic number and injection radius of
the fRC are chosen to be 12 and 1.55 m, respectively tomatch the beam structure from the RRC. The extraction radius is determined as 3.30 m from the velocity
gain (2.13) in the fRC. A sector angle is chosen to
be 58◦ taking into consideration beam focusing in thefRC, and the determined maximum magnetic ﬁeld is
1.68 T. The acceleration voltage per turn is 0.7–1 MV
using two RF cavities to obtain a large turn separation. Since the fRC is operated at a frequency threetimes that of the RRC, a ﬂat-top cavity is equipped toenlarge phase acceptance (± 10◦ ).
The layout of the fRC is shown in Fig. 2. As shownin Fig. 2, the fRC is composed of four sector magnets,3)
two main RF cavities, one ﬂat-top cavity, injection andextraction channels, beam diagnostics, and one vacuum system. Each sector magnet consists of a pair ofmain coils, ten pairs of trim coils, poles and a yoke.
The weight of the sector magnet is approximately 370
t and the height is 4.38 m. The gap of the magnet is
50 mm and the medium plane is 1.7 m from ﬂoor tomatch the existing beam line.
The isochronous magnetic ﬁeld of the fRC is produced by the main and trim coils in the magnet. The

Fig. 1. Acceleration scheme in RIBF.
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277

Fig. 2. Layout of fRC.

number of turns of the main coil is 70 and the maximum ampere-turn of the main coil is 90 kAT. The
main coils of the sector magnets are connected to a
power supply in series. The trim coils of one sector
magnet consist of six pairs with a maximum currentof 200 A and four pairs with one of 100 A. The power
supplies of the trim coils are prepared, 24 for 200 A
and 8 for 100 A, to carry out small corrections of A/q
diﬀerence as well as construction and alignment errors.
The upper and bottom poles of the sector magnet
form part of a vacuum chamber due to the limitationof construction height. For this reason the surface ofeach pole is coated with thin Ni to avoid outgas fromiron.
An RF system is composed of two main RF cavities and one ﬂat-top cavity located at valley sections,as shown in Fig. 2. The main cavity has a single acceleration gap and its maximum voltage is 350–500 kV(depending on radius) with the maximum consumption power of 100 kW. The ﬂat-top cavity is of 3f-typeand driven at 165 MHz. The maximum consumption
power of the ﬂat-top cavity is 30 kW. Each cavity has
a ﬁne tuner to correct changes in frequency originatingfrom construction errors and changes in temperature.
The vacuum system is composed of six cryopumps
used for main evacuation and two sets of turbomolecular and rotary pumps and two sets of mechanicalbooster and rotary pumps used for rough evacuation.
In each valley box with the main RF cavity, two cryopumps are located and in the other two valley boxes,
two cryopumps are located. The evacuation speed of
one cryopump is 13000 l/s to achieve 4 × 10−5 Pa.4)
In the fRC, one main radial probe (MDP), one phaseprobe (PP), one extraction radial probe (ERP), someslits and Faraday cups are prepared, mainly for beamdiagnostics. The MDP is a distractive probe that canmove almost over the entire range from the injection

278

radius to the extraction radius and can measure thebeam current cut in steps of 0.5 mm for radial direction. The MDP can also measure the remaining part.
The PP consists of 14 pairs of parallel plate pickups
with a gap of 30 mm. In one pair of pickups, approximately 10 turns of beam pass through. The PP measures phase by timing the beam passing through the
pickups. This information is used for ﬁne tuning to
produce the isochronous magnetic ﬁeld. Slits are located at the entrance of each magnetic channel. These
slits are separated into four parts (up, down, left, andright) that can read beam current approximately.
As shown in Fig. 2, the injection and extraction
channels are composed of two magnetic channels andone electrostatic channel, respectively. The main speciﬁcations of each channel are summarized in Table 2.
In Table 2, the minus sign shows that the magnetic
ﬁeld is in the direction opposite to that of the sector
magnet. Each magnetic channel has correction coils to
avoid the appearance of the magnetic ﬁeld in the acceleration orbit. The EIC has a hole for the injection
beam. The position of each channel can be changed.
The fRC is now under construction. The sector magnet is almost completed. The valley boxes including
the main RF cavity will be completed by March 2005.
Installation in the E4 room of the Nishina building will
start from June 2005. The ﬁrst commission is planned
for September 2006.
Table 2. Main specifications of injection and extraction
channels.
Name
MIC2
MIC1
MDC1
MDC2
Name
EIC
EDC

Magnetic channels
Radius Max. magnetic Bending angle(m)field (T)(degree)
0.72
0.16
80
0.87
0.16
40
2.15
−0.06
19
2.30
−0.14
20
Electrostatic channels
GapMax. Voltage
Length
(mm)
(kV)
(m)
12
120
0.5
12
120
0.55

References
1) Y. Yano: Proc. 17th Int. Conf. on Cyclotrons and Their
Applications, Tokyo, 2004-10, to be published.
2) H. Ryuto et al.: Proc. 17th Int. Conf. on Cyclotrons andTheir Applications, Tokyo, 2004-10, to be published.
3) T. Mitsumoto et al.: Proc. 17th Int. Conf. on Cyclotrons
and Their Applications, Tokyo, 2004-10, to be published.
4) S. Yokouchi et al.: RIKEN Accel. Prog. Rep. 38, 279(2005).

RIKEN Accel. Prog. Rep. 38 (2005)

Design of vacuum system for RIKEN fRC
S. Yokouchi, N. Fukunishi, A. Goto, N. Inabe, M. Kase T. Mitsumoto,∗ H. Ryuto, N. Sakamoto, and Y. Yano
We aim at producing a beam transmission of morethan 99% for 238 U71+ in the ﬁxed-frequency ring
cyclotron (fRC).1) The pressure required to achieve
this goal was estimated using the beam transmission(η) equation η = exp(−Cpσ T L), where C = 2.5 ×
1014 molecules/cm3 · Pa, p the beam chamber pressure
in Pa, σ T the sum of the electron capture and loss crosssection in cm2 , and L the path length of a beam incm. By using Bezt-Schmelzer approximations for the
low energy range,2) the capture and loss cross sections
are calculated to be 2.9 × 10−18 and 2.0 × 10−19 cm2 ,respectively. In the high energy range of the fRC, theloss cross section above should be corrected becauseof underestimation. Therefore, the σ T would be estimated to be 3.9 × 10−18 with a correction factor 5.2)
The L of 238 U71+ is calculated to be 2.6 × 105 cm forspeciﬁcations of the fRC.1) Consequently, the pressure
required in the fRC vacuum system is calculated to beless than 4 × 10−5 Pa from the above equation.
Figure 1 shows a schematic diagram of the vacuum
pumping system for the fRC. The vacuum pumping

system consists of two rough evacuation systems, twohigh-vacuum pumping systems, and six main pumps.
The rough evacuation system having a roots vacuum
pump of 400 m3 /h is installed at each valley chamber. The high-vacuum pumping system having a turbomolecular pump of 2200 L/s is installed at each RF
resonator. A cryopump of 13 m3 /s is used as the main
pump. Two cryopumps are installed at each RF resonator, and one cryopump is installed at each valley
chamber.
The total volume of the vacuum chamber is 16 m3 .
The main materials used in the vacuum system arestainless steel, copper, Ni-plated iron, and ﬂuoroelastomer. These inner surface areas and outgassing
rates are summarized in Table 1. The total throughput outgassed from the vacuum chamber is calculated by summing those outgassed from all materials. The calculated total throughput is approximately
4.6 × 10−2 t−1.2 Pa · m3 /s, where t is the pumping downtime in hours. The total eﬀective pumping speed ofthe main pump is 49 m3 /s.

Fig. 1. Schematic diagram of vacuum pumping system for fRC.
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Table 1. Inner surface area and outgassing rate of the fRC
vacuum chamber. The outgassing rate (Throughput
which is outgassed at a given time from a material,
divided by the area of the surface of the material.) isapproximated by a continued product of pumping downtime t (h). The throughput outgassed from each material is the product of its outgassing rate by its innersurface area.
Material
Stainless steel
CopperNi-plated iron
fluoroelastomer

Inner surface area
(m2 )
70
92
45
2.0

Outgassing rate
(Pa · m3 /s · m2 )2.0 × 10−5 t−1.0
5.3 × 10−5 t−1.0
8.7 × 10−4 t−1.5
1.3 × 10−3 t−0.64

The pumping down time from an atmospheric pressure of the vacuum chamber to 50 Pa by rough evacuation is estimated to be about 26 min. The pumping
down time from 50 Pa to 1 × 10−2 Pa by high-vacuum
evacuation is estimated to be about 1.7 h. The cryopump is started at 1 × 10−2 Pa and normally operated
after its cooling down time of 2 h. It takes 10 h after a normal operation of the cryopump to reach therequired pressure of 4 × 10−5 Pa. Figure 2 shows anoutline of the pumping down curve. As shown in thisﬁgure, the goal of about 14 h and a pressure in therange of 10−6 Pa, about 50 h after starting the vacuum
pumping system, are expected. The pressure is estimated to reach the very low range of 10−6 Pa in the

280

Fig. 2. Outline of pumping down curve.

long term.
The vacuum pumping system will be installed in2006.
References
1) N. Inabe et al.: RIKEN Accel. Prog. Rep. 38, 277(2005).
2) The K500⊗K1200 — A Coupled Cyclotron Facility at
the National Superconducting Cyclotron Laboratory:
NSCL Report MSUCL-939, 64 (1994).

RIKEN Accel. Prog. Rep. 38 (2005)

Construction status of IRC
J. Ohnishi, M. Kase, N. Sakamoto, K. Ikegami, S. Yokouchi, M. Nagase, M. Fujimaki,
H. Mikami,∗ H. Okuno, N. Fukunishi, A. Goto, and Y. Yano
A plan view of the intermediate-stage ring cyclotron(IRC) is shown in Fig. 1.1) Four sector magnets were
installed at the RIBF accelerator building in 2003.2)
The magnet and the vacuum systems were completed
by November, 2004. A brief outline of the construction
carried out in 2004 is as follows. A work schedule isshown in Fig. 2.

Fig. 1. Plan view of the IRC.

(1) Piping for the cooling water in the IRC room.
The cooling water system for the IRC consists ofﬁve routes for the cooling of the following: main coils,
trim coils, RF resonators and the magnets for the beam
injection and extraction, RF ampliﬁers, equipment for
the vacuum pumping system. After the piping and ﬂow
tests, the operation of the cooling water system started
for the magnet and the vacuum pumping systems.
(2) Installation of the RF resonators and the valley
chambers.
The RF resonators and the valley chambers wereplaced and aligned with the positional accuracy of better than 0.5 mm in the horizontal and the vertical directions. A photograph of the installed main RF resonators is shown in Fig. 3. The resonators are connected to the beam chambers in the sector magnets
with pneumatic seal joints.
(3) Assembly of the vacuum pumping system.
A layout of the vacuum pumping system is shownin Fig. 4. It consists of two rouging pumping lines,
four main pumping lines with turbo molecular pumpsof 3,200 L/s, twelve cryopumps of 10,000 L/s and twoof 4,000 L/s. Further twelve diﬀerential pumping lines
are used for the subvacuum of the RF resonators andthe beam chambers for the sector magnets.
(4) Installation of the magnetic channels.
The magnetic channels for the beam injection andextraction system (MIC1, MIC2, MDC1, and MDC2)
were placed with the positional accuracy of better than
1 mm.

Fig. 2. Work schedule of the IRC construction in 2004.
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281

(5) Wiring for the magnet system.
The magnets and their 52 power supplies were wiredwith approximately 400 cables. The magnet system
consists of four sector magnets, each of which has twopairs of main coils and 20 pairs of trim coils, and sevenmagnets for the beam injection and extraction system.
(6) Operation start for the vacuum pumping system.
Evacuation of the vacuum chambers started after

the wiring and checking of the pumps, valves, gauges
and safety system. The helium leak test was carriedout while the pressure was lowered. First operation of
the cryopumps started on November 10 and the designpressure of 10−5 Pa was achieved on November 15.
(7) First excitation of the magnets.
After tuning of the power supplies for the magnets,
all the magnets were excited at their respective maximum current. As a result, the magnets, the power
supplies and the cooling water system were conﬁrmed
to be good.
The wiring and the power test for the RF system andthe installation of the beam diagnostic system will be
carried out and the whole IRC will be completed in2005.
References
1) T. Mitsumoto et al.: AIP Conf. Proc. 600, 167 (2001).
2) J. Ohnishi et al.: Proc. 1st Annual Meeting of Particle
Accelerator Society of Japan, Funabashi, 2004-8 (Institute of Quantum Science, Nihon University, 2004),
p.224.

Fig. 3. The installed main RF resonator.

Fig. 4. Layout of the vacuum pumping system.

282

RIKEN Accel. Prog. Rep. 38 (2005)

Status of magnets for the SRC
H. Okuno, N. Fukunishi, J. Ohnishi, K. Ikegami, T. Tominaka,
S. Yokouchi, T. Fujinawa, A. Goto, and Y. Yano
In January of 2004 the assembly of the SRC sector
magnet began in the SRC vault with the goal of having
the first beam operable by the autumn of 2006. This
paper is a report on its progress for this year.
Figure 1 shows cross-sectional and plan views of thesector magnet. Its length and height are 7.2 m and
6 m, respectively. The weight is about 800 tons per sector. Its main components are a pair of superconducting
main coils, four sets of superconducting trim coils, a radiation shield, a cryostat chamber, thermal insulation
support links, twenty-two pairs of normal conducting
trim coils, warm poles and a yoke. The details of its
structure are described in Ref. 1. Figure 2 shows abird’s-eye view of the vertically expanded sector magnet explaining the assembly procedure. The assemblyin the SRC vault proceeds in the following order: theFig. 2. Expanded view of the sector magnet for the SRC.

Fig. 1. Cross-sectional view of the sector magnet.

lower yoke, the lower cold mass assembly, the side wallof the cryostat, the upper cold mass assembly and theupper yoke. The cold mass assemblies consist of thesuperconducting coils, the radiation shields, the poles
and other parts. They were assembled in the factories
to improve the quality of assembly.
Figure 3 shows the SRC vault at the present time
(Nov. 2004). The canning of the entire cryostat has almost been completed. The assembly of the upper yoke
is ongoing. Alignment accuracy of all parts was typically 0.1–0.2 mm. Before the welding of the cryostat, ahigh sensitivity total leak test of all the He vessels andpipes was carried out. These tests will decrease therisks that cold leaks will occur during cooling-down of
the superconducting coils.
The level of the floor and sector magnet of the SRC
has been monitored, as shown in Fig. 4, to see howmuch the floor subsides due to the heavy weight of thesector magnet. The data suggest that the floor aroundthe east wall has subsided by 2 mm and remained so forseveral months. The level of the lower yoke was readjusted before the cold mass assemblies were installedon the yoke. They were measured again two months283

Fig. 3. Photograph of the SRC during assembling.

Fig. 4. Subsidence of the floor level in the SRC. Periods
1, 2, and 3 indicate the following. 1: Delivery of slabs
for the yoke and the shield into the SRC and Big-RIPS
vaults, 2: Assembly of the lower yokes and 3: Transfer
of most slabs from the Big-RIPS vaults into the SRC
vaults.

284

later, and the base plane of the sector magnet was
found to be tilted by 0.4 mm/20 m. The mode of thelevel change is not thought to be harmful to the performance of the SRC. The floor level will be monitored
until beam commissioning.
Assembly of the sector magnet, which is ongoing,
will be finished in July of 2005. The superconducting
coils will be cooled from the middle of August and will
be excited in October. The magnetic field maps will
be taken until the end of January 2006. The othercomponents will be installed by the end of April 2006
for the power test of the rf-system. Finally, beam commissioning is scheduled to be performed in the autumn
of 2006.
Reference
1) A. Goto, H. Okuno, J. Ohnishi, T. Tominaka, S.
Fujishima, K. Ikegami, N. Fukunishi, Y. Miyazawa, T.
Mitsumoto, and Y. Yano: IEEE Trans. Appl. Supercond. 14, 300 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Development of liquid helium flow meter for the SRC magnets
H. Okuno, T. Tominaka, J. Ohnishi, K. Ikegami, A. Goto, and Y. Yano
The SRC has two types of superconducting coils:
the main coils and superconducting trim coils. The
main coils are cooled in the liquid helium bath andthe superconducting trim coils are indirectly cooled bya forced two-phase helium ﬂow. The cooling circuit isdivided into three parallel circuits to cool 48 sets of superconducting trim coils. It is very important to tune
individually ﬂow rate in the three parallel circuits using control valves installed in lines to uniformly cool all
the trim coils. Flow meters of liquid helium are necessary to tune ﬂow rate. In any cases, oriﬁce plates areinserted to the line to monitor ﬂow rate. It measuresthe diﬀerence in pressures upstream and downstreamof the oriﬁce plate. To have some sensitivity for liquid helium, the diameter of the oriﬁce should be suﬃciently small so that pressure decrease at the oriﬁce isvery large during the initial cooling at room temperature. Therefore, we need to install many additional
bypass valves, which are expensive low-temperature
valves and render the cooling system complex. So, wedeveloped a cup-type liquid helium ﬂow meter insteadof the standard oriﬁce ﬂow meter, to realize a systemless expensive and simpler. We adopted multihole cups
to widen their available ranges. In the next section thedetails of the ﬂow meter will be described.
The ﬂow meter is composed of a cup with some holes
and a level indicator for liquid helium as shown in
Fig. 1. The discharge rate of liquid helium from ahole is proportional to the square root of pressure exerted by liquid helium ﬁlling the cup. When discharge
rate is equal to pouring rate, the liquid surface remains
at an appropriate level, which can be measured using a level indicator. The available range of ﬂow rate
for a singe-hole cup is insuﬃciently small because ﬂow
rate is proportional to the square root of liquid column height. To obtain a wide range, we adopted amultihole cup, which shows approximately the linear
dependence of ﬂow rate on the height of liquid in an
appropriate range.
We performed experiments to determine the relationship between ﬂow rate and liquid helium level.
First, liquid helium was transferred from the dewar
and to the cup. Secondly, after completing the transfer, the level of liquid helium was monitored as a function of time. Flow rate can be plotted as a functionof liquid helium level from the measurements. Figure
2 shows the data in the case of using cups with four
4-mm-diameter holes at the levels of 1.3, 8.8, 16.3 and23.8 cm from the bottom. Their relationships agree

Fig. 1. Conceptual drawing of cup-type flow meter for liquid helium.

Fig. 2. Measured relationship between flow rate and liquid
He level.

well with the expectation and the cups can measure
ﬂow rate in a required range (5–40 cc/s). We tested
three cups that have the same structure. Obtained
data also coincided with each other. The tested ﬂow
meters were installed in the helium vessel for the SRC
to monitor ﬂow rate in the cooling lines for the superconducting trim coils.

285

RIKEN Accel. Prog. Rep. 38 (2005)

Present status of liquid-helium supply and recovery system
K. Ikegami, M. Ohtake, T. Tominaka, and Y. Yano
The liquid-helium supply and recovery system1) atthe Wako campus can generate liquid helium at a rateof 200 /h from pure helium gas. It has been stably
operated since the beginning of April 2001. Volumesof liquid helium supplied per year are listed in Table 1.
The volume supplied has gradually increased over theyears and it will soon be more than twice that suppliedin 2001. This is due to the increase in the number ofusers for nanoscience projects such as the advanced device laboratory, the nanomaterial laboratory, and the
low-temperature physics laboratory.
The recovery system consists of a recovery compressor, a gas bag and three recovery stations. The recovery compressor has a blow rate of 130 m3 /h at a pressure of 15 MPa. The gas bag has a volume of 100 m3
and is placed in the liquid-helium supply and recovery
building. The ﬁrst recovery station has a gas container
with a volume of 20 m3 and a blower with a blow rateof 80 m3 /h. It is placed near the cooperation building for the advanced device laboratory located on thesouth side of the RIKEN campus. The second recovery
station has a gas container with a volume of 40 m3 anda blower with a blow rate of 80 m3 /h. It is placed in
the RIKEN main research building and is connected to
the frontier research building and the frontier material
Table 1. Volumes of liquid helium supplied per year from2001 to 2003.
Year
2001
2002
2003

286

Volumes of supplied liquid helium (k)
28
40
52

research facilities building. The third recovery stationis placed behind the east brain science building locatedon the east side of the RIKEN campus and connectedto the Nishina memorial building. In the near future,
the new RIBF accelerator building will also be connected to it through a recovery pipe. In March 2005,
a new recovery station that has one gas container witha volume of 30 m3 and one blower with a blow rate of
80 m3 /h will be installed in front of the chemistry andmaterial physics building for the nanoscience project.
At the same time, impure gas cadres with a volume of1800 m3 will be added to the system to compensate forthe increase in the volume of recovered helium gas.
For approximately one year, problems with impurity
in the system have occurred. The recovered helium gas
contained 1–2 ppm of hydrogen gas. The gas is liqueﬁed after puriﬁcation with an internal device installedin the refrigerator. However, about 0.06 ppm hydrogen
had entered the liquid helium storage vessel because
the capacity of the 20 K adsorber in the refrigerator
was not suﬃcient to remove all the hydrogen gas in
the helium. As a result, the hydrogen in the liquid
helium caused a blockages in the dilution refrigerators
which are used for the nanoscience project. In orderto remove the hydrogen and the impure gases in theliquid helium storage vessel, The temperature of thevessel had to be raised to room temperature. Afterreplacing the pure helium gas, the storage vessel wascooled back to 4.2 K.
Reference
1) K. Ikegami et al.: RIKEN Accel. Prog. Rep. 34, 349(2001).

RIKEN Accel. Prog. Rep. 38 (2005)

Status of the BigRIPS separator project
T. Kubo, K. Kusaka, K. Yoshida, A. Yoshida, Y. Mizoi,∗1 N. Fukuda,
N. Aoi, H. Sakurai,∗2 T. Motobayashi, and Y. Yano
The large-acceptance superconducting in-ﬂight RI
beam separator BigRIPS1) is under construction forphase I of the RI beam factory (RIBF) project. The
BigRIPS separator is characterized by two major features: large acceptances and a two-stage separator
scheme. The large acceptances are achieved by using large-aperture superconducting triplet quadrupoles(STQ), allowing the eﬃcient production of RI beams
by the in-ﬂight ﬁssion of uranium beams. The twostage separator scheme allows one to deliver tagged
RI beams: The ﬁrst stage of BigRIPS serves to
produce and separate RI beams using the techniquecalled momentum-loss achromat, while the second
stage works as an analyzing section to identify RIbeam species in an event-by-event mode. Since the
RI-beam purity is poor in our energy domain, thepresent scheme signiﬁcantly facilitates RI-beam experiments such as secondary reaction studies of unstable
nuclei. The integrated capability of the BigRIPS andRIBF cyclotrons is expected to enlarge the scope of RI-

beam experiments signiﬁcantly, promoting studies on
the properties and reactions of unstable nuclei further
from the stability.
The BigRIPS separator is followed by the phaseI RI-beam delivery line, which transports the tagged
RI beams to experimental setups placed downstream.
Figure 1 shows a schematic layout of the phase-I RIBF
project, in which two RIBF cyclotrons, the BigRIPS
separator, and the RI-beam delivery line are shown.
Part of the delivery line, as shown in the ﬁgure, hasbeen designed to also serve as a zero-degree forward
spectrometer which we call ZDS spectrometer. Thiswas made possible by adopting the same quadrupoles
and dipoles as those of BigRIPS for the delivery line. A
secondary target surrounded by γ-ray array detectors
is placed in the starting focus point of ZDS spectrometer, while projectile residues from secondary reactions
are analyzed and identiﬁed by the ZDS spectrometer.
In-beam γ-ray secondary reaction studies will be extensively made for a variety of unstable nuclei using

Fig. 1. A schematic layout of the RI beam factory project in 2007 (RIBF phase I).
∗1∗2Osaka Electro-Communication University
Department of Physics, University of Tokyo

287

the ZDS spectrometer.
The construction schedule for the BigRIPS separator
project is shown in Fig. 2, along with that of the RIbeam delivery line. Most of the BigRIPS construction
will be ﬁnished in early 2006. The construction of thedelivery line will start in 2005, its completion beingscheduled for early 2007. The ﬁrst RI-beam production
using BigRIPS is scheduled in late 2006, while RI-beamexperiments will start in April, 2007.
Fabrication of the BigRIPS magnets consisting offourteen superconducting triplet quadrupoles (STQ)and six room-temperature dipoles was ﬁnished in
March, 2004. In the case of the ﬁrst-stage magnets
consisting of ﬁve STQs and two dipoles, their installation has also been ﬁnished, along with the cryogenic
plant to be used for the cooling of STQs.2) Stand-alone
test operation of the cryogenic plant was carried out
in April, 2004, in order to measure the heat loads ofthe transfer line as well as the cooling capacity of thecryogenic plant.3) A cooling capacity higher than thedesign value has been obtained.
The second-stage magnets consisting of nine STQs
and four dipoles are currently being stored in the BigRIPS hall until their installation in 2005. The fab-rication of the delivery-line magnets consisting of ten
STQs and two dipoles will also begin in 2005.
The design and fabrication of the focal plane devices, such as vacuum chambers, degrader control, slit
control, collimator, stopper and detector tables, arecurrently being carried out.4) The focal plane devices
will be placed in a vacuum chamber at each focus of
BigRIPS, being employed to tune not only the production and separation of RI beams but also the RI-beamtagging. The fabrication will be ﬁnished in March,
2005.
In order to cope with the beam power of 100 kW
at RIBF, the design, study and development of thehigh-power water-cooled rotating-disk production target5) and the high-power water-cooled swirl-tube beam
dump6) are progressing. As for the beam dump, awater-cooled swirl tube has been tested by irradiatinga high-power laser beam. Recent analysis of the data
indicates that the swirl-tube beam dump can withstand the expected power density at BigRIPS.6)
The ZDS spectrometer has been designed to havediﬀerent optics mode, which allows one to choose
the appropriate mode depending experimental requirements.7)
Test operation of the cryogenic plant started in October, 2004, to cool the ﬁrst-stage STQs, and is still inprogress as of November.
References

Fig. 2. Schedule of the BigRIPS separator project.

2881) T. Kubo: Nucl. Instrum. Methods Phys. Res. B 204,
97 (2003).
2) K. Kusaka et al.: RIKEN Accel. Prog. Rep. 38, 291(2005).
3) T. Kubo et al.: RIKEN Accel. Prog. Rep. 38, 289(2005).
4) K. Yoshida et al.: RIKEN Accel. Prog. Rep. 38, 293(2005).
5) A. Yoshida et al.: RIKEN Accel. Prog. Rep. 38, 296(2005).
6) Y. Mizoi et al.: RIKEN Accel. Prog. Rep. 38, 295(2005).
7) Y. Mizoi et al.: RIKEN Accel. Prog. Rep. 38, 297(2005).

RIKEN Accel. Prog. Rep. 38 (2005)

Stand-alone test operation of the BigRIPS liquid-helium cryogenic
plant and heat-load measurement of its cryogenic-temperaturetransfer line
T. Kubo, K. Kusaka, K. Yoshida, A. Yoshida, Y. Mizoi,∗1 N. Kakutani,∗2 T. Tsuchihashi,∗2
M. Shimada,∗2 K. Sato,∗2 M. Nagami,∗3 T. Kumaki,∗3 M. Nobutoki,∗3 and Y. Katou∗3
The ﬁve surpeconducting triplet quadrupoles (STQ)on the ﬁrst stage of the BigRIPS separator1) are cooled
by a large liquid-helium cryogenic plant, the main
components of which are a Linde-TCF50S refrigerator, a Maekawa 315 kW compressor, and a 50-m-longcryogenic-temperature helium-transfer line. The cryogenic plant supplies liquid helium and 70 K gas heliumin a refrigeration mode to the STQs through the transfer line. Each STQ is connected to the transfer line
by way of its valve box unit and U-shaped cryogenictemperature tubes. The 70 K gas helium is used tocool 70 K shields of the transfer line as well as those of
STQ cryostats. More details are described in Ref. 2.
The system, including the STQs and the cryogenic
plant, was fabricated by Toshiba Corporation andTaiyo Nippon Sanso Corporation, and were installed in
the RIBF building in March 2004. Some photographsof the BigRIPS cryogenic plant are shown in Ref. 3.
Stand-alone test operation of the BigRIPS cryogenic
plant was carried out in April 2004, in order to measure not only the cooling capacity of the refrigerator
but also the heat loads of the transfer line. In the operation, the STQs were disconnected from the system byclosing the cryogenic-temperature valves in the valve
box units, and liquid nitrogen, which can enhance thecooling capacity, was not employed in the ﬁrst heatexchanger of the refrigerator.
In the measurement of the cooling capacity,
cryogenic-temperature valves at the cold end of therefrigerator were closed so that the transfer line wasdisconnected. The cooling capacity to supply liquid
helium, which we call the 4.3 K cooling capacity, wasmeasured by saving liquid helium in the phase separator dewar inside the refrigerator and keeping theliquid-helium level constant by switching on a heaterin the phase separator. The measured input power tothe heater corresponds to the 4.3 K cooling capacityof the refrigerator. In the measurement of the cooling
capacity to supply 70 K gas helium, which we call the70 K cooling capacity, heat loads to the 70 K shields
were simulated by switching on a heater installed at
the inlet position of the ﬁrst turbine.
The operation conditions of the refrigerator, such aspressure, temperature, conductance of control valves,
rotation speed of two turbines and so on, were adjusted, so that the cooling capacities could be opti∗1∗2∗3

Osaka Electro-Communication University
Toshiba Corporation
Taiyo Nippon Sanso Corporation

mized. The results are listed in Table 1 along with thedesign cooling capacities. Fortunately, the measured
values are higher than the design values for both cooling capacities. This may be because the eﬃciency ofthe heat exchangers as well as that of the turbines in
the refrigerator are higher than what is expected in thedesign.
In measuring the heat loads to the transfer line, liquid helium and 70 K gas helium were supplied to thetransfer line by opening the supply and return valvesat the cold end of the refrigerator. End valves locatedat the end of the transfer line were also opened, sothat the liquid and gas helium could return to the refrigerator. The supplied liquid helium returns in twophases to the phase separator, while the 70 K gas helium returns to the inlet of the ﬁrst turbine as in theusual operation mode. During this operation mode,the operation conditions of the refrigerator were kept
the same as those in the stand-alone operation, including the temperature of water that cools the compressor. The heater power at the inlet of the ﬁrst turbine
was adjusted such that the same operation conditions
could be attained. The heater power to the phase separator was also adjusted so as to keep the liquid level
constant.
The diﬀerence in the heater power between thestand-alone and heat-load measurement operations indicates the heat loads to the transfer line: 4.3 K heatloads and 70 K heat loads. The measured values arelisted in Table 1 along with the design values. Unfortunately, the measured 4.3 K heat loads are higher thanthe design value. This is because 70 K shields in someparts of the transfer line were not actually installed.
On the other hand, the measured 70 K heat loads were
smaller than expected, for the same as above.
Table 2 summarizes the cooling capacity, measured

Table 1. Measured cooling capacities and transfer-line(T.L.) heat loads.
4.3 K cooling capacity
70 K cooling capacity

Measured
509 W
907 W

Design390 W
700 W

4.3 K heat loads to T.L.
114 W
62 W
70 K heat loads to T.L.
408 W
440 W
Main operation conditions: 1.59 MPaG at the exitof compressor, 1.33 MPaG at the inlet of ﬁrst turbine, water temperature 19◦ C.

289

Table 2. Summary of measured and expected performanceof the BigRIPS cryogenic plant.
4.3 K performance
Cooling capacity
Extra cooling capacity
Total heat loads
Transfer line
Valve boxes andU-shaped pipes
STQs (STQ1-5)
Power leads
70 K performance
Cooling capacity
Extra cooling capacity
Total heat loads
Transfer line
Valve boxes andU-shaped pipes
STQs (STQ1-5)

290

509 W
267 W
242 W
114 W

(measured)(measured)

40 W
18 W
70 W

(estimated)(measured oﬀ line)(estimated)

907 W
212 W
695 W
408 W

(measured)(measured)

62 W
225 W

(estimated)(measured oﬀ line)

and expected heat loads, and expected extra cooling
capacity. The extra cooling capacity is expected to be
267 W for 4.3 K heat loads and 212 W for 70 K heatloads. These capacities will be used for radiation heatloads due to fast neutrons that are emitted from theproduction target and the beam dump located near the
STQs.
Test operation of the cryogenic plant, including theﬁrst-stage STQs, began in October 2004, and was stillin progress as of November 2004.
References
1) T. Kubo: Nucl. Instrum. Methods Phys. Res. B 204,
97 (2003).
2) T. Kubo et al.: RIKEN Accel. Prog. Rep. 36, 316(2003).
3) K. Kusaka et al.: RIKEN Accel. Prog. Rep. 38, 291(2005).

RIKEN Accel. Prog. Rep. 38 (2005)

First stage of BigRIPS separator
K. Kusaka, T. Kubo, K. Yoshida, A. Yoshida, Y. Mizoi,∗1
N. Kakutani,∗2 T. Tsuchihashi,∗2 and K. Sato∗2
An in-ﬂight RI beam separator named BigRIPS1)
is being built for the RIBF phase-I project. Large
acceptances and a two-stage separator scheme characterize the BigRIPS separator. While the large acceptances are achieved by the use of superconducting
quadrupoles with large apertures, the two-stage separator scheme allows tagged RI beams to be delivered.
The ﬁrst stage of the BigRIPS separator serves to produce and separate RI beams, while the second stage
serves to identify RI-beam species in an event-by-event
mode. Here we report the current status of the ﬁrst
stage of the BigRIPS separator.
Figure 1 shows a schematic layout of the ﬁrst stageof the BigRIPS separator. The main magnetic components are ﬁve superconducting quadrupole triplets(STQ) and two room-temperature dipoles. The ﬁve
STQs are cooled by liquid helium (LHe) which issupplied by a large-scale, integrated cryogenic systemthrough a transfer line. The transfer line and valve
boxes are also shown in Fig. 1.
While the STQs and the dipole magnets were fabricated by Toshiba Corporation and completed in the
beginning of 2004, the large cryogenic system was fabricated by Nippon Sanso Ltd. and some of its components, such as the cold box (Fig. 2), buﬀer tanks(Fig. 3), and compressors (Fig. 4), were installed in
the RIBF building in 2003. The design of the cryogenic
system has been reported elsewhere.2) Installation of
the magnet system of the ﬁrst stage, the ﬁve STQs in-

Fig. 2. Cold box (TCF50S), joint box, and, LHe dewar.

Fig. 3. Buﬀer tanks.

Fig. 4. Main compressor.

Fig. 1. Schematic layout of the ﬁrst stage of BigRIPS separator.
∗1∗2

Osaka Electro-Communication University
Toshiba Corporation

cluding the cryogenic system and the two dipoles, wascomplete by the end of March 2004 (Fig. 5). A standalone test of the cold box and measurements of heatloads of the transfer line were also performed in 2004.3)
Table 1 summarizes the main parameters of STQs.

291

Table 1. Speciﬁcations of STQs.

Type
Eﬀective length [m]Max. ﬁeld gradient [T/m]Warm bore radii [mm]Cold mass weight [Ton]Hexapole coilSTQ1
air-core
0.5, 0.8, 0.5
24, 20, 20
90, 120, 120
4
downstream

STQ2
superferric←
14.1 all120 all
8
upstream

Fig. 5. BigRIPS cave.

STQ1 is an air-core superconducting quadrupole
triplet and its maximum ﬁeld gradients are 24, 20,
and 20 T/m.4) These strong gradients enable us to collect rapidly diverging radioactive isotopes created at
the target. The remainder (STQ2-STQ5) are of a superferric type in which quadrupole ﬁeld distribution ismainly generated by hyperbolic shaped cold iron poles,
and the maximum ﬁeld gradient is 14.1 T/m.5) In bothtypes, three quadrupoles are rigidly connected to eachother and stored in a single LHe vessel and cooled
by LHe supplied through the transfer line. The 80 K
shields surrounding the LHe vessels are also cooled bygas helium supplied from the cold box, so that no liquid nitrogen shield is used. To cool the current leads,
which connect the cold coils and the room-temperaturebusbar, newly developed a gas-cooled current leads
have been used. Toshiba developed the gas-cooled current lead with multiple electrodes in a single coolinggas channel, so no multi channel gas control is required.6)
Since neutron radiation from the production target
and the beam dump, installed in the ﬁrst dipole, is
expected to give radiation damage to nearby components, we have carefully selected materials used to built
the magnets and cryogenic system. For the coils of superconducting quadrupoles, we use a NbTi superconducting wire with polyester-imide (PEI) insulator. PEI
is chosen for the insulation material, since it is less sen-

292

STQ3
←
←
←
←
←
downstream

STQ4
←
←
←
←
←
upstream

STQ5←
0.5, 1.0, 0.5
←
←
←
no

sitive to radiation than polyvinyl formal enamel (PVF)
which is widely used as the insulation material of superconducting wire. In the cryogenic system we haveused a radiation-resistant superinsulator (SI) made ofaluminized polyimide ﬁlm and an aramid ﬁber net
these materials are considered to be less sensitive to radiation damage than polyester (PET) sheets and nets,
which are widely used for SI. The radiation-resistantSI is used in the cryostats of STQ1, STQ2, and STQ3,
part of the transfer line, namely, the U-tubes, somevalve boxes, and, a part of the main transfer tubes.
In addition to the radiation damage, a large ﬂux
of neutron radiation causes signiﬁcant heat loads tothe cold mass of the STQ1 and STQ2 cryostats. We
have designed our cryogenic system with extra cooling
capacity in order to cope with radiation heat loads.2)
Furthermore, a heater system controlled by the LHelevel in the cryostats is installed in each STQ. The
maximum heater powers of each cryostat are 100 W
for STQ1 and STQ2 and 20 W for STQ3, STQ4, andSTQ5. This heater system ensures stable operation of
the cold box and the compressor.
The license required to operate our cryogenic system
was issued in October 2004 by the Saitama municipal
goverment. The ﬁrst cool-down operation of the total cryogenic system began in October. After 10 daysof a puriﬁcation run, about 20 days were required forprecooling and about 10 days to ﬁll LHe into all the
STQ cryostats. Measurements of extra-cooling capacity, heat loads of the each part of cryogenic system,and tests of heater control will be reported in the near
future.
References
1) T. Kubo: Nucl. Instrum. Methods Phys. Res. B 204,
97 (2003).
2) T. Kubo et al.: RIKEN Accel. Prog. Rep. 36, 316(2003).
3) T. Kubo et al.: RIKEN Accel. Prog. Rep. 38, 287(2005).
4) K. Kusaka et al.: RIKEN Accel. Prog. Rep. 37, 297(2004).
5) T. Hirumachi et al.: IEEE Trans. Appl. Supercond. 10,
236 (2000); K. Kusaka et al.: IEEE Trans. Appl. Supercond. 14, 310 (2004).
6) N. Kakutani et al.: RIKEN Accel. Prog. Rep. 37, 299(2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Design of focal-plane devices for BigRIPS
K. Yoshida, T. Kubo, N. Fukuda, N. Aoi, K. Kusaka, and A. Yoshida
A design has been developed for the focal-plane devices of fragment separator BigRIPS.1) Figure 1 shows
the BigRIPS beam line, consisting of 6 normal conducting dipole magnets and 15 super conducting triplet
quadrupole magnets. There are 8 focus along the beamline as shown in Fig. 1. A rectangular vacuum chamberis placed at each focus, which is equipped with devices
necessary for beam selections and beam diagnoses aswell as a vacuum pump.
The ﬁrst focus F1 is a dispersive focus where thehorizontal position of the beam depends on its magnetic rigidity. Therefore, the slit at F1 can be used to
select the magnetic rigidity of secondary beams. Slit
blades are designed to use 40-mm-thick copper blocks
with water cooling. The material and the thicknessof the blades are chosen with the consideration of the
stopping power and the weight. While the blades canstop secondary beams with Z ≥ 7, lighter secondary
beams with Z ≤ 6 may pass through the slit blades.
However, these beams are swiped out by the dipole
magnet downstream of the separator. After the slit,a wedge-shaped energy degrader is placed to produce
mass dispersion. In the design, 4 types of degrader
are installed and can be changed without breaking thevacuum of the F1 chamber. Two of these types havethe mechanism for adjusting the wedge angle. The required change in wedge angle is accomplished by the
combination of the rotation and the horizontal shiftof the wedge in the following manner. The rotationof the wedge leads to the changes in angle and thickness, while the horizontal shift compensates the change
in thickness. Two Joker slits, which stop a part ofthe beam within the acceptance of the separator, arealso placed in order to prevent the mixture of charge
states of primary beams entering to the downstreamof the separator. Two position-sensitive parallel plateavalanche counters (PPACs)2) are provided to observe
the position and angular distributions of the beams at
F1.
The second focus F2 is an achromatic focus where
the position of the beam does not depend on the momentum of the secondary beam. With the help of theFig. 1. Focal-plane devices of BigRIPS separator.

293wedge degrader at F1, isotope separation is attained
at F2. The slits and detectors in the F2 chamber are
respectively used for the isotope selection and roughidentiﬁcation of the beam species. The two PPACs installed in the F2 chamber monitor the beam position
and angle. The ion chamber (IC)3) and Si detector areused to measure the energy loss of the beam, which isrelated to Z of the secondary beam. The plastic scintillator (PL) gives the beam arrival time. From thisbeam arrival time, the time of ﬂight (TOF) of the beam
between the production target and F2 is obtained together with the rf signal of the accelerator. Since the
TOF is related to A of the beam, the identiﬁcationof the beam isotope is accomplished using the abovementioned detectors. A beam stopper is also placedin the F2 chamber to stop the beam when we need toaccess the downstream of the BigRIPS.
The section of the BigRIPS between the third focus
F3 to the seventh focus F7 is used for beam tagging.
Secondary beam species and their momentum are measured in an event-by-event mode. The positions andangles of the beam are measured using the PPACs in
the F3, F5, and F7 chambers. Since the F5 is a dispersive focus, the position of the beam at F5 corresponds
to the momentum of the beam with the correction of
the position of the beam at F3. The energy loss of thebeam is measured using the IC in the F3 or F7 chamber. The IC has been speciﬁcally developed to handle
a high beam rate.3) The TOF of the beam is obtained294

using the PLs in the F3 and F7 chambers. The precise
measurement of TOF with the correction of the ﬂight
pass diﬀerence due to the position, angle and momentum of the beam makes it possible to identify the Z, A,
and charge state q of the beam species when A/q is not
close to an integer number.1) The PPACs in the F4 andF6 chambers are used to check the beam position. The
slit and the degrader in the F5 chamber can be used
for the second-stage isotope selection. The ladders in
the F3, F4, and F6 chamber can be used to mount thecollimator. The degrader ladder in the F7 chamber
can be rotated and used for the energy adjustment of
the secondary beam.
The eighth focus F8 is provided for experiments using dispersive secondary beams. PL for TOF measurement and PPACs for position monitoring are installedin the F8 chamber.
Based on the above conceptual design, the mechanical design and fabrications of these chambers and devices are now in progress, and their installation will be
performed in 2005.
References
1) T. Kubo: Nucl. Instrum. Methods Phys. Res. B 204,
97 (2003).
2) H. Kumagai et al: Nucl. Instrum. Methods Phys. Res.
A 470, 562 (2001).
3) K. Kimura et al.: Nucl. Instrum. Methods Phys. Res.
A 538, 608 (2005).

RIKEN Accel. Prog. Rep. 38 (2005)

Laser-beam testing of prototype swirl-tube beam dump for
BigRIPS separator
Y. Mizoi,∗1 N. Fukuda, T. Kubo, K. Yoshida, K. Kusaka, A. Yoshida,
N. Kakutani,∗2 T. Okuyama,∗2 and K. Sato∗2
We have performed a laser-beam irradiation test forthe prototype beam dump, and conﬁrmed that thepresent design of the beam dump appeared to havea suﬃcient ability to cool the 100-kW beam heat expected at the RIBF.
Details of a prototype of the beam dump are described in Ref. 1. A test measurement using a CO2
laser-beam was performed at Toshiba Co. Ltd.
We measured the change in temperature at the surface of a sample piece, on which carbon powder was
sprayed and the laser-beam was subseqently irradiated.
Since we know the speciﬁc heat capacity, the density
and the volume of the sample, we can estimate theabsorbed heat under adiabatic conditions. Although
this measurement was performed in atmosphere, it iswell known that the adiabatic approximation is very
reliable for estimating the absorbed power.
The laser-beam spot size was measured in two ways;
measurement of the size of a melted hole on a Lucitesurface and direct measurement using a laser-powermonitoring device. The spot sizes obtained by thesemeasurements were both approximately 4 mm in diameter.
A water pump was tuned so that the water ﬂowed
at the required velocity. Water pressure was estimatedby the relationship between the pressure and the ﬂow,
which is a characteristic of the pump. The laser-beamirradiation and the temperature were measured using
an IR camera and a thermocouple, which was soldered
at a distance of 6 mm from the center of the beam spot.
The temperature was measured by changing the waterﬂow velocity and the laser power. The water velocity
was changed to 8, 10 and 12 m/s, and the laser power
was also changed to 0.5, 1.0, 1.3 and 1.5 kW for eachwater velocity.
Figure 1 shows the thermograph image obtained under the condition of a water velocity of 12 m/s and alaser power of 1.5 kW which corresponds to a heat density of about 70 MW/m2 . The maximum temperatureon the tube surface was about 360◦ C. Figure 2 shows
the result of the ANSYS calculation, which can reproduce the temperature distribution shown in Fig. 1.
The detailed analyses are now in progress.

∗1∗2

Fig. 1. Thermograph image obtained under the conditionof water velocity of 12 m/s and laser power of 1.5 kW.

Fig. 2. Result of the ANSYS calculation.

Reference
1) Y. Mizoi et al.: RIKEN Accel. Prog. Rep. 36, 318(2003).

Osaka Electro-Communication University
Toshiba Corporation

295

RIKEN Accel. Prog. Rep. 38 (2005)

Development of production target for BigRIPS separator
A. Yoshida, Y. Mizoi, Y. Takahashi, T. Kubo, K. Yoshida, and K. Kusaka
A conceptual design of the water-cooled rotating target system for the projectile fragment separator (BigRIPS) is investigated (Fig. 1). To facilitate the maintenance of the target system in a high radiation environment, an all-in-one structure is considered. That is,
two sets of rotating target mechanics and other beamdiagnostic detectors, such as a beam viewer, a Faraday cup and a beam proﬁle monitor, are planned to be
mounted on one vacuum ﬂange. Each set of the target mechanics slides perpendicular to the beam axis tochange the eﬀective target thickness. For maintenance,
it is planned that the all-in-one ﬂange will be removed
using a remote-controlled handling transportation system.
A part of a mockup for the target system was constructed (Fig. 2) on the basis of the design studies ofthis target system.1–4) A rotating target wheel with adiameter of 30 cm and a maximum rotation speed of
1krpm was applied, which are acceptable target parameters even for the severest operating condition of a 238 U
primary beam with an energy of 350 MeV/nucleon andan intensity of 1 particle µA. A sample target wheel
was mounted on a water-cooled disk. Cooling water

Fig. 2. Mockup of the target system. A sample target
wheel (1) and a water-cooled disk (2) connected toa double-piped shaft (3) were rotated using a motor(4). The motor, a rotary joint (5) and a ferromagnetic
feedthrough (6) are planned to be placed in a small
vacuum tight box. All the target mechanics can slide
perpendicular to the beam axis using a vacuum motor(7).

was introduced in to the disk through a double-piped
shaft. The wheel and the disk were rotated using a
motor. This motor and the rotary joint used for thecooling-water inlet are planned to be placed in a small
vacuum tight box, and the ferromagnetic feedthroughused here isolates the vacuum region. The lengthof the double-piped shaft was designed to be 60 cm
to satisfy the radiation hardness of the ferromagnetic
feedthrough, which was measured and estimated to belarger than 0.5–1.5 MGy.5)
A high-speed rotation test was performed under airpressure. The target wheel was smoothly rotated ata speed of 1 krpm and its oscillation was as small as±0.5 mm in the radial direction. In the next step of
this mockup test, the above-mentioned small vacuum
tight box will be introduced and an endurance test
under vacuum pressure will soon be performed.
References

Fig. 1. A conceptual design of the target chamber. Twosets of rotating target mechanics (1), a beam viewer(2), a Faraday cup (3) and a beam profile monitor (4)are planned to be mounted on one vacuum flange (5).

2961) A. Yoshida et al.: RIKEN Accel. Prog. Rep. 34, 188(2001).
2) A. Yoshida et al.: RIKEN Accel. Prog. Rep. 35, 152(2002).
3) A. Yoshida et al.: Nucl. Instrum. Methods Phys. Res.
A 521, 65 (2004).
4) A. Yoshida et al.: RIKEN Accel. Prog. Rep. 37, 295(2004).
5) A. Yoshida et al.: Research Report of Laboratory of
Nuclear Science, Tohoku University, 36, 111 (2003).

RIKEN Accel. Prog. Rep. 38 (2005)

Design of RI-beam delivery line and zero-degree recoil separator
Y. Mizoi,∗1 T. Kubo, H. Sakurai,∗2 K. Kusaka, K. Yoshida, and A. Yoshida
We have designed an RI-beam delivery line and azero-degree recoil separator (ZDS) to be located after the BigRIPS separator for the RIBF project inphase I. Figure 1 shows a schematic top view ofthem. The RI-beam delivery line and ZDS are being built in the experimental hall. Magnetic devices
used in the RI-beam delivery line and ZDS are anormal-conducting dipole magnet, and a superconducting triplet-quadrupole magnet with a small refrigerator. The designs of these magnets are same as thoseof the BigRIPS separator.
There are four experimental ports, denoted as P1
to P4 on the RI-beam delivery line. P1 is placed ona dispersive focal plane, and the others are placed on
the double-achromatic focal plane.
The beam line from P2 to P4 is designed to operate not only as the delivery line but also as a
double-achromatic spectrometer system for use as a
ZDS. The ZDS has the conﬁguration of TQ-D-TQTQ-TQ-TQ-D-TQ, where TQ and D denote a triple-

quadrupole magnet and a dipole magnet, respectively.
The secondary-reaction experiments can be carried out
on the P2 port in corporation with the ZDS, and we
expect that the ZDS will be used in three modes, ahigh-resolution mode, a large-acceptance mode, anda dispersive mode, depending on the experimental
conditions. A promising experiment for the highresolution and large-acceptance modes is γ-ray spectroscopic measurement. A secondary target and a γray detector array are installed at P2. The γ rays
are measured with a γ-ray detector array by tagging
a recoil particle with the ZDS in the high-resolution
mode or the large-acceptance mode. A promising experiment for the dispersive mode is secondary-reaction
spectroscopy with precise recoil-momentum analysis.
The beam envelopes of the high-resolution mode, thelarge-acceptance mode, and the dispersive mode areshown in Figs. 2, 3, and 4, respectively. The opticalparameters of the diﬀerent modes are also summarizedin Table 1.

Fig. 1. Schematic top view of BigRIPS separator, RI-beam delivery line and ZDS. There are four
experimental ports indicated by P1 to P4. The focal planes of ZDS are indicated by F-A to F-D.

Fig. 2. Beam envelopes of high-resolution mode.
∗1∗2

Osaka Electro-Communication University
Department of Physics, University of Tokyo

297

Fig. 3. Beam envelopes of large-acceptance mode.

Fig. 4. Beam envelopes of dispersive mode.

Table 1. Optical parameters are listed. The parameters of the high-resolution mode and the largeacceptance mode are summarized in the left-hand table. Those of the dispersive mode are summarized
in the right-hand table. F-B, F-D, and F-M denote focal planes indicated in Figs. 2, 3 and 4. x and ydenote the horizontal and vertical lengths in meters, respectively. θ and φ denote the horizontal andvertical angles in radians, respectively. δp denotes the ratio of momentum spread (dp) to momentum(p), δp = dp/p.
Plane
F-B

F-D

Parameter
(x|x)
(x|θ)
(x|δp)(θ|x)(θ|θ)(θ|δp)
(y|y)
(y|φ)
(φ|y)
(φ|φ)
(x|x)
(x|θ)
(x|δp)(θ|x)(θ|θ)(θ|δp)
(y|y)
(y|φ)
(φ|y)
(φ|φ)

High resolution
−1.00
0.00
2.12
0.00
−1.00
0.00
−2.68
0.00
0.00
−0.37
−1.00
0.00
0.00
0.00
−1.00
0.00
−1.00
0
0
−1.00

Large acceptance
−2.00
0.00
2.48
0.23
−0.50
0.00
−2.24
0.00
0.00
−0.45
−1.00
0.00
0.00
0.93
−1.00
0.00
−1.00
0.00
0.00
−1.00

The construction of the RI-beam delivery line andZDS will be started in 2005, and they will be ready for

298

Plane
F-M

F-D

Parameter
(x|x)
(x|θ)
(x|δp)(θ|x)(θ|θ)(θ|δp)
(y|y)
(y|φ)
(φ|y)
(φ|φ)
(x|x)
(x|θ)
(x|δp)(θ|x)(θ|θ)(θ|δp)
(y|y)
(y|φ)
(φ|y)
(φ|φ)

Dispersive mode
−2.03
0.00
4.20
0.00
−0.49
0.00
−5.82
0.00
0.00
−0.17
1.00
0.00
−4.13
0.00
1.00
0.00
1.00
0
0
1.00

experiments by the end of FY 2006.

RIKEN Accel. Prog. Rep. 38 (2005)

Rf cavity with parallel-plate radial lines
T. Koseki and M. Izawa∗
For modern electron storage rings such as highluminosity colliders and high-brilliance synchrotron radiation sources, the suppression of the coupled-bunch
instability due to higher-order modes (HOMs) in rf
cavities is one of the most important issues for achieving a high beam current limit. In this paper, we present
a new HOM damper for rf cavities in electron storagerings.
The design of the new HOM damper is based on
the rf cavity of the Photon Factory (PF) storage ringin KEK.1–3) The PF cavity has beam ducts of siliconcarbide (SiC) that are 140 mm in diameter. All HOMs
having a frequency higher than the cutoﬀ frequency of
the 140 mmφ duct (1.64 GHz and 1.26 GHz for TM01
and TE11 modes, respectively) are dissipated by the
SiC duct.
The HOM damper, proposed in this paper, employs parallel-plate radial transmission lines on the
beam duct instead of the SiC duct. Figure 1 showsa schematic view of the cavity with a radial line. The
outer end of the radial line is terminated by the sintered SiC, the same material as the beam duct absorber of the PF cavity. The HOMs, extracted fromthe center of the cavity through the beam duct, couple
the radial waves in the radial line and are dissipated in
the SiC absorber. The design of the center part of thecavity is the same as that of the present PF cavity, andthe property of the accelerating mode is not changed.
The choke mode cavity developed in KEK also employs the radial transmission line to extract HOMs.4)
Since the lowest radial transmission line mode does nothave a cutoﬀ frequency, the radial line requires a choke
structure to block the accelerating mode. However, thecavity shown in Fig. 1 does not need any ﬁlters in theradial line because the frequency of the accelerating

Fig. 1. The damped cavity with radial line damper.
∗

mode is suﬃciently less than the 140 mmφ cutoﬀ frequency.
The calculated characteristics of the accelerating
mode and HOMs are summarized in Table 1. Rs and
Rt in the table are the longitudinal and transverse
impedances, respectively. The resistivity of the SiC
absorber was assumed to be 20 Ω cm in this calculation. As shown in this table, HOMs with a frequency
higher than the cutoﬀ frequency of the 140 mm φ duct
are dissipated well. Only a certain number of HOMs,
whose frequencies are lower than the cutoﬀ frequency,
are trapped in the cavity and continue to have a highimpedance. To avoid instabilities due to the “trappedmodes”, the frequency-shift method using two ﬁxed
tuners should be applied, as in the case of the present
PF cavity.2) The ﬁxed tuner is a blank ﬂange, which
has an appropriately chosen block length to adjust thetrapped-mode frequencies so that they do not coincidewith the coupled-bunch mode frequencies. Since thefrequency-shift method is eﬀective for the modes witha high Q-value, the radial line damper is positioned
keeping the appropriate distance from the center ofthe cavity so as not to dampen the Q-values of trappedmodes halfway. To maintain the high Q-value of theTM111-like mode (transverse 0.99 GHz), it is preferable that the radial line damper is not positioned closer
to the center of the cavity than the position shown in
Fig. 1.
One of the notable features of the cavity using theradial line damper is its short length in the longitudinal
direction. For the cavity shown in Fig. 1, the total
length between the taper transition ﬂanges is 870 mm,
which is 490 mm smaller than that of the original PF
cavity.
In order to estimate the wall heating in the radialline damper, we calculated the longitudinal wake ﬁeld
induced by a Gaussian bunched beam using the time
domain solver of MAFIA. The loss parameter k is deﬁned by the total energy loss ∆U and total charge inthe bunch Q as follows:5)
∆U
1 ∞k= 2 =
ρ(s)W (s)ds,
Q
Q −∞where s is the longitudinal coordinate, ρ(s) is the longitudinal charge distribution of the bunch and W (s)is the longitudinal wake potential. The bunch length
dependence of k is shown in Fig. 2. Power loss in theradial line damper is not so serious and heat problems
due to large bunch current can be easily avoided using
the simple water-cooling system in the same manneras the SiC duct of the present PF cavity.6)

High Energy Accelerator Research Organization (KEK)299

Table 1. Summary of accelerating mode and HOMs of the cavity.
Longitudinal modes
Frequency
Q
Rs
[GHz]
[kΩ]
0.5005 41958 7394.20
0.7941 36514 1899.63
1.05674
0.21
1.05674
0.03
1.1625 38439
0.95
1.3121 56659
525.661.3725 27859
245.591.702288
0.03
1.719550
0.03
1.761774
0.53
1.7916109
0.11
1.815889
0.01
1.880842
0.05
1.906256
0.02
2.03522009
0.24
2.0983794
0.00
2.1646100
0.02
2.1718286
1.07
2.226739
0.00

Transverse modes
Frequency
Q
Rt
[GHz]
[kΩ/m]
0.7059 45191
339.080.7924 49024 13491.64
0.9906 21981
9910.391.1915309
13.08
1.2242210
2.02
1.26115
1.75
1.26126
0.01
1.289840
2.83
1.331965
0.49
1.3695349
1.77
1.45811264
30.22
1.5173942
10.18
1.5450777
2.09
1.5781321
9.83
1.6214204
0.64
1.6999174
0.11
1.7570451
3.22

References
1) T. Koseki, M. Izawa, and Y. Kamiya: Rev. Sci. Instrum.
66, 1926 (1995).
2) M. Izawa et al.: J. Synchrotron Radiat. 5, 369 (1998).
3) T. Koseki: RIKEN Accel. Prog. Rep. 37, 306 (2004).
4) T. Shintake: Jpn. J. Appl. Phys. 31, L1567 (1992).
5) A. W. Chao: Physics of Collective Beam Instabilities
in High Energy Accelerators (John Wiley & Sons, New
York, 1993).
6) M. Izawa, T. Koseki, Y. Kamiya, and T. Toyomasu:
Rev. Sci. Instrum. 66, 1910 (1995).
Fig. 2. Bunch length dependence of the loss parameter ofthe radial line damper.

300

RIKEN Accel. Prog. Rep. 38 (2005)

High current RFQ linac
M. Okamura, J. Takano,∗ K. Yamamoto,∗ T. Hattori,∗ and N. Hayashizaki∗
Since 2001, we have been conducting experiments
to verify the direct plasma injection scheme (DPIS)
using an existing RFQ in TITech, Tokyo. The obtained maximum current of carbon beam was 9.2 mA,
which agreed well with our simulation value.1) With
this achievement, we decided to construct a new RFQ
to attain a higher current using the DPIS. We believe this new technique will have great impact on theheavy-ion accelerator ﬁeld.
To demonstrate the intrinsic performance of the
DPIS, the new RFQ was constructed at the Institutefor Applied Physics (IAP), Goethe University, Frankfurt. This RFQ was designed to accelerate carbon 4+
and 6+. The target current was set at 100 mA with
C4+ . The chosen operation frequency was 100 MHz
since it is available using an RF ampliﬁer system. The
resonant structure is the 4-rod type, which is well established in IAP and suited for this frequency region
and low-duty factor operation. It has a reasonably
small diameter, and the ﬁeld distribution is easy totune. Moreover it is not diﬃcult to replace vanes infuture modiﬁcations. The total vane length was set at
2 m considering future modiﬁcations however, the output beam energy is 100 keV/u, which is limited by aradiation safety regulation. The beam is accelerated
up to 100 keV/u within the ﬁrst 1.42 m section andthen transported through nonmodulated vanes to theend of the RFQ. In the nonmodulated section, the accelerated beam is completely debunched and this will
reduce the space charge eﬀect in an analyzing section,
which will be constructed in the near future. The input
energy of the beam is a very important value, because
in DPIS a high-voltage-biased slit is located at the entrance of the RFQ and might cause discharges. Part ofthe very high intensity plasma is guided through theseveral mm diameter hole in the biased slit and enter
the RFQ. To minimize the beam size emitted fromthe hole, the slit needs to be close to the vanes. At thesame time, we have to prevent sparking and an eﬀect
on the resonant condition of the cavity. We adopted
60 kV as the total input beam energy based on our
experience. In case of C4+ , the value corresponds to20 keV/u as the injection energy. The position of theslit can be adjusted. A picture and summarized design parameters of the RFQ are shown in Fig. 1 andTable 1, respectively. The vane parameters of the RFQ
were designed to maximize beam acceptance. To conﬁrm the particle dynamics in the RFQ, PteqHI wasused. This code was developed by one of authors andcan simulate multiple charge states simultaneously.
We have been investigating two types of laser sys∗

Tokyo Institute of Technology

Fig. 1. 100 MHz RFQ. The cube box behind the RFQ isthe ion source.

Table 1. Basic design parameters of the RFQ.
Frequency
Total length
Modulated vane length
Limit of intervane voltage
Iout at 100 mA C4+ inSaturated Iout , C4+ only
Iin for saturated Iout
Acceptance
Aperture

100 MHz
2.0 m
1.42 m120 kV
76 mA
155 mA∼ 300 mA
0.14 cm·rad
0.655 cm

tem for plasma production. Currently a CO2 laser isused for our experiment. The maximum output energyof the CO2 laser is 8 J. However, the emitted energy
to the carbon target was measured to be 1.2 J with apulse width of 85 ns (FWMS). Our plasma measurement experiment showed that, under this condition of
the laser system, C4+ (50%) is mainly produced andthe rest of the ions are C5+ (35%) and C3+ (15%). We
can assume that these three-charged state ions are injected to the RFQ. We also measured the property ofthe plasma induced by a Nd-YAG laser system. Thislaser has an output energy of 300 mJ and can produce
mainly C6+ (50%).2) This laser system is now planned
to be used in the next DPIS experiment. The measured result also shows that the Nd-YAG laser plasma
can provide suﬃcient beam current to the RFQ.
Ion sources parts, including the plasma production
solid target and the space which will be ﬁlled by the ablated plasma, have to be isolated electrically and maintained at a high voltage corresponding to the beam injection energy of the RFQ. Sixty kilovolts is applied to301the ion source part which is too high to insulate in an
atmosphere. Therefore, high-voltage parts are locatedin a vacuum. The high-voltage connector is at the bottom of the TEFLON sleeve that is 30 cm long, and acable from the high-voltage power supply is inserted
to the sleeve. The high-voltage parts are not shown
from outside of the vacuum box. As we mentioned
above, all the energy fed to the plasma is provided
by laser shot. This means that both a large terminal
stage and a safety fence are not required and the ion
source part can be made extremely compact and simple. Behind the vacuum box, the laser beam is injected
through double NaCl windows and guided to the highvoltage region. A concave mirror reﬂects and focuses
the laser beam on to the carbon target. Plasma is theninduced and expanded towards the RFQ. Finally, theexpanding plasma that can be accommodated in thehigh-voltage slit is injected to the RFQ.
We obtained the ﬁrst beam in June 2004 after overcoming the sparking problem. The measured peak current reached 30 mA with a slit having 4-mm-diameterhole. We optimized various parameters for the C4+
beam and obtained a maximum peak current of morethan 50 mA. Under this condition, the inner diameterof the slit is 6 mm. A typical beam shape is shown in
Fig. 2. This signal was from a Faraday cup immediately after the RFQ. The applied repetition rate was
1 Hz, which was limited by the laser system.
The input current and emittance have not beenmeasured. At the C4+ peak, a tracking analysis
of beam extraction indicate that with a 4-mm-

302

Fig. 2. Accelerated beam out of RFQ. The laser pulse isdrawn using arbitrary unit.

diameter extraction slit, ∼100 mA with an emittanceof ∼0.45 cm·rad enters the RFQ. The RFQ simulation
then showed that ∼40% is transmitted. With a 6-mmdiameter extraction slit, ∼200 mA with an emittance of∼0.6 cm·rad enters the RFQ and ∼25% is transmitted.
In this regime, output current saturation is expected.
References
1) M. Okamura et al.: Laser Part. Beams 20, 451 (2002).
2) H. Kashiwagi et al.: Rev. Sci. Instrum. 75, 1569 (2004).

RIKEN Accel. Prog. Rep. 38 (2005)

Proof examination of alternating-phase focusing
K. Yamamoto,∗ M. Okamura, T. Hattori,∗ N. Hayashizaki, and J. Takano
Recently, cancer therapy has been one of the major
applications of hadron accelerators. In a typical conventional design, a chain of linacs occupies a large area
in cancer-therapy facilities. For example, an injectorof HIMAC (heavy ion medical accelerator in chiba)
consisting of an RFQ linac and an Alvarez linac accelerates C4+ ions up to 6 MeV/u; the length is morethan 30 m.1) Particularly in such a medical accelerator complex, not only machine performance, but also
cost performance is very important. Therefore, a compact and reliable linac has been highly required. For
this purpose, we designed an Interdigital-H mode linac
with alternating-phase focusing as a high-eﬃciency injector. The IH structure has an advantage of a highshunt impedance in the low-energy region. The APF
has not yet successfully accelerated beams, although
it has been proposed for the design of short low-beta
structures due to the elimination of the external transverse focusing by drift-tube quadrupoles.2–5)
The basic parameters were determined for O+ acceleration, which were mainly an injection energy of
10 keV/u, an acceleration energy of 77 keV/u and an
operation frequency of 63.3 MHz. For stable operationand eﬃcient acceleration, the electric-ﬁeld strength in
the gaps and the eﬀective acceleration voltage were determined to be twice the Kirpatric limit and 4 MV/m,
respectively. On the basis of these conditions, the linac
was designed to be 0.53 m in length. The number ofcells is 16, which ware determined by the linac length
divided by the average cell length. Gap voltage andlength was designed as follows, (1) The ﬁrst gap length
was determined to be half of the ﬁrst cell length. (2)The nth gap voltage distribution was determined tomaintain the total acceleration voltage. (3) All of the
gap length was determined to be twice the Kilpatriclimit of the electric-ﬁeld strength. On the basis of theabove design conditions, we optimized the phase pattern for APF to work eﬀectively using the thin-lensapproximation.
Next, we constructed a half-scale cold model to determine the length of an end-ridge tuner to obtain therequired electric-ﬁeld distribution. The measurement
was carried out by a perturbation method; a small aluminium ball was placed onto the acceleration axis, andthe electric ﬁeld at this position was obtained by measuring the variation in the frequency. The electricﬁeld distribution was obtained by changing the ballposition. The optimum electric-ﬁeld distribution was
obtained at a cut-area length of 150 mm. The result isshown in Fig. 1 and the ﬁnal parameters are summarized in Table 1. On the basis of these parameters, the∗Tokyo Institute of Technology

Fig. 1. Measurement results of electric-field distribution oflinac.
Table 1. Design parameters of linac.
Q/A
Input Energy
Output Energy
Frequency
Number of cells
Cavity length
DiameterTransverce AcceptancePhase Acceptance
Gap voltage

1/16
10.8 keV/u77.2 keV/u63.3 MHz16
530 mm
630 mm
88π mm·mrad
30 degree
74–145 kVbeam dynamics was re-calculated.
The cavity was processed within an accuracy of±0.1 mm. After plating Cu on the cavity, the drift
tubes and the length of each gap were aligned at an
accuracy of ±1% (Fig. 2). The vacuum was checked
after assembling the side plates. The frequency and
Q-values were 63.32 MHz and approximately 15370, respectively.
An acceleration test of a proton beam was carriedout in the test bench as shown in Fig. 3. A PIG ion
source with an extraction voltage of 10.8 kV was utilized to supply protons. For a low-energy beam transport, a solenoid lens was prepared. Acceleration energy
after the IH linac was analyzed by a bending mag-Fig. 2. Photograph of IH linac with APF.

303

Fig. 5. Energy spectrum of accelerated beam. The accelerated proton is shown at an energy of 77 keV.
Fig. 3. Photograph of the experimental set-up.

net after focusing by an electric-quadrupole lens. Slits
were placed after the magnet to improve the resolution(Fig. 4).
Figure 5 shows the energy spectrum of accelerated
ions. The ﬁgure clearly shows that the protons wereaccelerated up to the design energy. During this measurement, the focusing-lens strength was adjusted sothat the accelerated-ion current would be maximum
at the Faraday cup (FCN3) after the bending magnet.
Since the slit in front of the FCN3 was fully opened,
the signal widths in the energy spectrum do not indicate energy dispersal. Figure 6 shows accelerated
energy and ion current as a function of RF power.
The gap voltage, obtained from the measured Q-value,corresponds to an RF power of 45 W. The acceleration eﬃciency of the IH linac was approximately 6%.
It should be noted that the PIG ion source supplied
beams under DC operation whereas the phase acceptance of the linac was 30 degrees. By pulsing the beamwith a buncher so that the beam-pulse length matches
the acceptance, the eﬃciency is expected to be eventually approximately 70%. Moreover, by improving thetransverse matching, the acceleration eﬃciency is estimated to be improved up to 8% even during the DC
operation of the PIG ion source.
A proof test of the IH linac with APF was successfully completed, which is the ﬁrst acceleration ofa beam by using the APF principle in the world. The

Fig. 6. Current and energy of accelerated proton beam asfunction of RF-power.

results of the proof examination using low-current proton beams are in good agreement with the numericalprediction. In order to evaluate the performance of theIH linac with APF, however, high-current and highenergy acceleration tests are highly required. We areplanning to accelerate C4+ ions up to a several MeV/uwith a several mA using a new linac and a new ECR
ion source.
References
1) S. Yamada et al.: Proc. APAC98, p.885 (1998).
2) T. Hattori et al.: Nucl. Instrum. Methods Phys. Res. B
161, 1174 (2000).
3) N. Hayashizaki et al.: Rev. Sci. Instrum. 71, 990 (2000).
4) V. V. Kushin et al.: Proc. PAC 1993, p.1798 (1993).
5) D. A. Swenson: Part. Accel. 7, 61 (1976).

Fig. 4. Layout of experimental setup.

304

RIKEN Accel. Prog. Rep. 38 (2005)

Inductance calculation of helical conductors†
T. Tominaka
The self- and mutual inductances for inﬁnitely longcoaxial helical conductors are investigated over the entire available range, from solenoids with an inﬁnitesimal pitch length to straight conductors with an inﬁnite
pitch length. The principal terms, apart from the logarithmically divergent term due to the inﬁnite lengthof the self- and mutual inductances, are rigorously obtained, using the analytical expressions for the vector
potential of a single helical thin conductor.1)
Generally, the self- and mutual inductances of inﬁnitely long conductors can be described with the double integrals of Neumann’s formula in the following
form:2)
  −

→ −
→
dl i · dl k
µ0
1
→
−
→
−
Lik =
=
A i (r, θ, z) · dl k ,4π i krik
Ii k(1)
where Lik (= Mik ) is the mutual inductance between
the ith and kth conductors, Lii is the self-inductance,
and Ai (r, θ, z) is the divergence-free vector potential
due to an inﬁnitely long helical conductor, which isexpressed in the form of the inﬁnite series of modiﬁed
Bessel functions of the ﬁrst and second kinds, In (nkr),
Kn (nkr), where k (= 2π/Lp ) is the pitch parameter,and Lp is the twist pitch length.
The self-inductance per unit length along the central
axis (z axis), L/l, of a long solenoid or a single helicalthin conductor, located at (r1 , ϕ1 , z = 0) of the circularcylindrical coordinate system with a pitch length L1 (=2π/k1 ), as shown in Fig. 1, can be calculated as follows:
∞
L
µ0
µ0 
= − ln r1 +Kn (nk1 r1 )In (nk1 r1 )
l
2π
π n=1

+

∞
µ0
µ0 k1 r12 
k1 r12 +{Kn+1 (nk1 r1 )2L1
L1 n=1· In+1 (nk1 r1 ) + Kn−1 (nk1 r1 )In−1 (nk1 r1 )}. (2)Fig. 1. Schematic view of two coaxial solenoids.

(or L1 → ∞), the self-inductance does not converge,
consistently with the inductance of a straight thin conductor. Therefore, we cannot neglect the cross sectionof the helical conductor, at least for the inductancecalculation near the limit of k1 → 0 (or L1 → ∞)corresponding to a straight conductor.
The calculated results for the self-inductance of a helical thin conductor with the winding radius of 10 mm
are shown in Fig. 2. The self-inductance calculated using the analytical expression of Eq. (2) up to the ﬁrst
one hundred terms (n = 100) is shown as the solid line,
and the conventional expression of Eq. (3) is shown as
the dashed line. In Fig. 2, it is clearly shown that theconventional approximate expression is applicable up
to approximately where the pitch length is equal to thewinding radius.
In order to calculate the accurate self-inductance fora helical conductor, including that at the limit of k → 0(or Lp → ∞), it is necessary to take into account theﬁnite cross section of the helical conductor.
The calculated results from a numerical surface integration for the self-inductance of a helical conductor

In the limit of k1 → ∞ (or L1 → 0), the self-inductance
per unit length coincides with the well-known result
calculated with the assumption of a uniform interior
magnetic ﬁeld.
limL

k1 →∞ l≈µ0
µ0
k1 r12 = 2 πr12 = µ0 n21 πr12 ,
2L1
L1

(3)

where n1 (= 1/L1 ) is the number of turns per unit
length and πr12 is the cross-sectional area of thesolenoid. The self-inductance of Eq. (3) does not contain the inﬁnite contribution of the exterior azimuthalﬁeld. On the other hand, in another limit of k1 → 0†

Condensed from the article in Supercond. Sci. Technol. 18,
214 (2005)

Fig. 2. Self-inductance per unit length for inﬁnitely longhelical conductor with winding radius of 10 mm, andconductor radii of inﬁnitesimally thin and 0.5 mm.

305

with the radius of 0.5 mm and the winding radius of
10 mm are shown as dots in Fig. 2. In this calculation,
the analytical expressions up to the ﬁrst ﬁfty terms(n = 50) are taken into account. When the radius of
the helical conductor decreases, more terms within theanalytical expression of the inﬁnite series are needed.
The mutual inductance per unit length, M/l of thesecondary solenoid, located at (r2 , ϕ2 , z = 0), with apitch length L2 (= 2π/k2 ), due to the ﬁrst solenoid at(r1 , ϕ1 , z = 0) with L1 (= 2π/k1 ), as shown in Fig. 1,
can also be calculated. Speciﬁcally, for case of k1 =k2 = k, and r1 < r2 , the following expression of mutual
inductance is obtained:
∞
M
µ0
µ0 
=−
ln r2 +In (nkr1 )Kn (nkr2 )
l
2π
π n=1
µ0 2 2 µ0 2
k r1 +
k r1 r2· cos[n(ϕ2 − ϕ1 )] +
4π
2π
∞

·
{In+1 (nkr1 )Kn+1 (nkr2 )12 mm and the angular diﬀerence of ∆ϕ = ϕ2 − ϕ1 =π/6 are shown in Fig. 3. The mutual inductance calculated using Eq. (4) up to the ﬁrst one hundred terms(n = 100), is shown as the solid line, and the approximated expression of Eq. (5) is also shown as the dashedline. In addition, the calculated results up to the ﬁrst
ﬁfty terms (n = 50) for two coaxial solenoids or helicalconductors with the radius of 0.5 mm are also shownas dots in Fig. 3.
Furthermore, it is shown that the calculations of theself- and mutual inductances for helical conductors of atwisted biﬁlar lead and a twisted superconducting multistrand cable are consistent with the magnetic energy
calculation.3,4)

n=1+ In−1 (nkr1 )Kn−1 (nkr2 )} cos[n(ϕ2 − ϕ1 )]. (4)In the limit of k1 , k2 → ∞ (or L1 , L2 → 0), it is shownthat the mutual inductance per unit length coincides
with the well-known result
r12 2πr2

µ0
M
≈
k1
l
4π r2 L2µ0µ0=
k1 r12 =πr 2 = µ0 n1 n2 πr12 .
2L2
L1 L2 1lim

k1 ,k2 →∞(5)

where n2 (= 1/L2 ) is the number of turns per unit
length of the secondary solenoid and πr12 is the crosssectional area of the inner solenoid. On the other hand,in another limit of k1 , k2 → 0 (or L1 , L2 → ∞), themutual inductance coincides with that of an inﬁnitely
long straight conductor.
The calculated results for the mutual inductance between two coaxial helical thin conductors of k1 = k2 =k (= 2π/Lp ) with the winding radii of 10 mm and

306

Fig. 3. Mutual inductance per unit length between two
coaxial solenoids of the same pitch lengths with windingradii of 10 and 12 mm and the azimuthal angular diﬀerence of ∆ϕ = π/6, and conductor radii of inﬁnitesimallythin and 0.5 mm.

References
1) T. Tominaka: Nucl. Instrum. Methods Phys. Res. A
523, 1 (2004).
2) A. Sommerfeld: in Electrodynamics, Lectures on Theoretical Physics, Vol. III, (Academic Press, New York,
1952), p. 104.
3) T. Tominaka and Y. Chiba: J. Phys. D 37, 1592 (2004).
4) T. Tominaka: Supercond. Sci. Technol. 18, 214 (2005).

RIKEN Accel. Prog. Rep. 38 (2005)

Routine work for radiation safety in the ring cyclotron facility
Y. Uwamino, S. Fujita, S. Ito, H. Sakamoto, R. Hirunuma, T. Yamaki, H. Mukai,∗1 A. Sato,∗2 and Y. Yano
We report here the residual radioactivity and leakage radiation level at the Riken Ring Cyclotron (RRC)
facility.
Residual radioactivities in the RRC facility were
measured at various locations using ionizationchamber survey meters. The measurements were performed after almost every beam experiment as wellas during the routine overhaul period. This year, theoverhaul was suddenly started at the end of June, because a serious failure of the contact ﬁngers of the RF
cavity was occurred during an experiment using an 80MeV/u alpha beam in the E3 room.
The dose rates at the deﬂector in the injector AVF
cyclotron were found to be 1.1 mSv/h on Aug. 18, 2004.
The dose rates at the RRC deﬂector were not measured
in this period, although those at magnetic deﬂection

channel 1 (MDC1) were measured. The highest rate
was 1.85 mSv/h on Aug. 9.
In addition to the above routine measurements, dose
rates inside the injector AVF cyclotron were measured
when its acceleration chamber was opened on Dec. 23,
2003, due to an insulation failure of the deﬂector. The
highest dose rate at the deﬂector was 4.2 mSv/h.
During the period from Oct. 1, 2003 to Sept. 30,
2004, the dose rates were measured along the beamlines. The spots a–v, marked by bullets in Fig. 1,
are the places where the dose rates exceeded 30 µSv/h.
Table 1 summarizes the observed dose rates andthe dates when the measurements were performed.
The maximum dose rate was found to be 1.4 mSv/h(1400 µSv/h) at the beam duct in the beam distribution corridor denoted by h in Fig. 1. When we observed

Fig. 1. Layout of the RIKEN Ring Cyclotron facility at the 1st basement floor as of 2004. Measured
locations of residual radioactivities along the beam lines are indicated by solid circles a–v. Locationsof the neutron and γ-ray measurements when the 86 Kr beam was on are indicated by open circles A,
B and H which are on the beam line level in the 1st basement and by open triangles of C to G which
are on the 2nd basement floor.
∗1∗2Japan Environment Research Corporation
Tokyo University of Science307

Table 1. Summary of dose rates measured along the beam lines with ionization-chamber survey meters.
Detection points a–v indicate measured locations shown in Fig. 1.
Detection
point
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v

Measured
dose rate(µSv/h)
130
400
1100
450
150
65
225
1400
200
85
30
170
230
100
35
35
360
350
1200
600
50
45

Date

Particle

Energy(MeV/u)Intensity(enA)

Period(days)

Apr 16,’04
Apr 16,’04
Apr 16,’04
Apr 16,’04
Apr 16,’04
Apr 16,’04
Jan 6,’04
Jan 6,’04
Jan 6,’04
May 13, ’04
May 13, ’04
Apr 16,’04
Apr 16,’04
Apr 16,’04
Mar 15, ’04
May 13, ’04
Apr 26,’04
Apr 26,’04
May 24, ’04
May 24, ’04
May 24, ’04
Jan 6,’04

Ne-20
Ne-20
Ne-20
Ne-20
Ne-20
Ne-20
Ar-40
Ar-40
Ar-40
Ar-40
Ar-40
Ne-20
Ne-20
Ne-20
He-4
Ar-40
N-14
N-14
d
d
d
Ar-40

135
135
135
135
135
135
95
95
95
95
95
135
135
135
26
95
135
135
65
65
65
95

10
10
10
10
10
10
1360
1360
1360
1000
1000
10
10
10
80
20
2450
2450
110
110
110
17

1
1
1
1
1
1
4
4
4
6
6
1
1
1
1
1
1
1
4
4
4
1

Table 2. Measured dose rates in and around the RRC facility when a 46-MeV/u 54-pnA 86 Kr beam wasstopped by a Faraday cup, FC-D1a, without any local shield. Measured points are shown in Fig. 1.
Measuredpoint
A

Neutron dose rate(µSv/h)0.03

Gamma dose rate(µSv/h)
LTD§

B
C
D
E
F
G
H

0.04
0.06
0.16
0.15
0.23
0.05
LTD

LTD
LTD
LTD
LTD
LTD
LTD
LTD

§

90 degree, 13 cm from the E4 wall surface,beam line height
1 m west from A
directly below the Faraday cup, on floor B2
1 m west from C
2 m west from C
3 m west from C
4 m west from C
outside the shielding door on the beam
distribution corridor

lower than the detection limit

a high dose rate, we cordoned oﬀ the area and posted
a warning sign to indicate that it was dangerous toremain for a long period in that place.
We paid particular attention to measuring the leakage radiations in and around the RRC facility when a
46-MeV/u 86 Kr beam of 54 pnA intensity was stopped
by a Faraday cup, FC-D1a, in the beam distribution corridor, without any local shield. Aloka TPS451BS neutron rem counters and AE133 V ionizationchamber γ-ray survey meters from Applied Engineering Inc. were used. The measured results were shownin Table 2. The leakage was found to be small, and was
below the detection limit outside the RRC building.
We also continuously monitored the leakage radia-

308

Remarktion from the RRC facility. Having analyzed the datacollected on leakage neutrons, we found that the radiation levels in the controlled area were much lower than
the allowable dose limit. The leakage of γ-rays andneutrons was below the detection limit of the environmental monitors. We evaluated the radiation level atthe boundary of the accelerator facility by using a monitor installed in the computer room on the ground ﬂoor
immediately above a bending magnet which guided thebeams from the RRC vault to the distribution corridor.
As a result, we obtained a radiation level of approximately 8.2 µSv/year which was much lower than theallowable dose limit (1 mSv/year).

VI. LIST OF PUBLICATIONS
1. Accelerator
physics

development

andaccelerator

A. Bandyopadhyay, O. Kamigaito, A. Chakrabarti, V.
Banerjee, P. Ghosh, A. Goto, and Y. Yano: “Design of the RFQ and the LINAC postaccelerator for
the VEC-RIB facility”, J. Phys. G 24, 1367–1370(1998).
M. Komiyama, I. Yokoyama, M. Fujimaki, J. Odagiri,
M. Nagase, T. Tanabe, and M. Kase: “Expansion of
the control system for RARF”, Proc. 14th Symp. on
Accelerator Science and Technology, (The Japanese
Accelerator Researchers Association and KEK),
Tsukuba, 2003–11, KEK, pp. 272–274 (2003).
D. Tomono, S. Nakamura, Y. Matsuda, M. Iwasaki,
G. Mason, K. Ishida, T. Matsuzaki, I. Watanabe,
S. Sakamoto, and K. Nagamine: “Precise measurement of the positive muon lifetime at the RIKENRAL muon facility ”, AIP Conf. Proc. 721, 293–296(2004).
Y. Matsuda, P. Bakule, P. Strasser, K. Ishida, T.
Matsuzaki, M. Iwasaki, Y. Miyake, K. Shimomura,
S. Makimura, and K. Nagamine: “Recent development of a point positive muon source at the RIKENRAL muon facility”, AIP Conf. Proc. 721, 313–316(2004).
A. Goto, H. Okuno, J. Ohnishi, T. Tominaka, S.
Fujishima, K. Ikegami, N. Fukunishi, Y. Miyazawa,T. Mitsumoto, and Y. Yano: “Sector magnets for
the RIKEN superconducting ring cyclotron”, IEEE
Trans. Appl. Supercond. 14, 300–305 (2004).
T. Tominaka, H. Okuno, J. Ohnishi, N. Fukunishi, H.
Ryuto, M. Ohtake, K. Ikegami, A. Goto, and Y.
Yano: “Radiation eﬀects on cryogenic temperature
sensors of Cernox, CGR and PtCo”, IEEE Trans.
Appl. Supercond. 14, 1802–1805 (2004).
T. Tominaka: “Analytical ﬁeld calculations for various
helical conductors”, IEEE Trans. Appl. Supercond.
14, 1838–1841 (2004).
T. Tominaka: “Calculations using the helical ﬁlamentary structure for current distributions of a six
around one superconducting strand cable and a multiﬁlamentary composite”, J. Appl. Phys. 96, 5069–
5080 (2004).
T. Tominaka and Y. Chiba: “Low frequency inductance for a twisted biﬁlar lead”, J. Phys. D 37, 1592–
1595 (2004).
H. Amemiya, T. Tanabe, and T. Katayama: “Coolingof ions by cold electrons through coulomb collisions”,
J. Phys. Soc. Jpn. 73, 617–626 (2004).
H. Ryuto, T. Chiba, H. Hasebe, M. Kase, and Y. Yano:“Liquid ﬁlm stripper for intense heavy-ion beams”,
Jpn. J. Appl. Phys. Pt.1 43, 7753–7755 (2004).
S. Kohara, A. Goto, N. Sakamoto, O. Kamigaito, S.
Watanabe, T. Teranishi, T. Katayama, Y. Chiba,

M. Kase, and Y. Yano: “Flattop acceleration system in the RIKEN AVF cyclotron”, Nucl. Instrum.
Methods Phys. Res. A 526, 230–238 (2004).
A. Chakrabarti, V. Naik, O. Kamigaito, S.
Dechoudhury, D. Bhowmik, D. Sanyal, A.
Bandyopadhyay, T. K. Chakraborty, M. Mondal,
S. Nayak, H. Pandey, T. K. Bhaumik, A. Giri,
D. Bhattacharya, T. J. Sen, S. Bhattacharya, A.
Goto, and Y. Yano: “The design of a four-rod
RFQ LINAC for VEC-RIB facility”, Nucl. Instrum.
Methods Phys. Res. A 535, 599–605 (2004).
T. Watanabe, S. Watanabe, T. Ikeda, M. Kase, Y.
Sasaki, T. Kawaguchi, and T. Katayama: “A prototype of a highly sensitive cryogenic current comparator with a HTS SQUID and HTS magnetic shield”,
Supercond. Sci. Technol. 17, 450–455 (2004).
T. Tominaka: “Inductance calculation for helical conductors”, Supercond. Sci. Technol. 18, 214–222(2005).

2.

Nuclear physics and nuclear instrumentation

S. Sugimoto, K. Ikeda, and H. Toki: “Relativistic meanﬁeld theory with pion ﬁeld for ﬁnite nuclei”, Prog.
Theor. Phys. Suppl., No. 146, pp. 437–441 (2002).
R. Kanungo, M. Chiba, S. Adhikari, D. Fang, N. Iwasa,
K. Kimura, K. Maeda, S. Nishimura, Y. Ogawa, T.
Ohnishi, A. Ozawa, C. Samanta, T. Suda, T. Suzuki,
Q. Wang, C. Wu, Y. Yamaguchi, K. Yamada, A.
Yoshida, T. Zheng, and I. Tanihata: “Possibility ofa two-proton halo in 17 Ne”, Phys. Lett. B 571, 21–
28 (2003).
K. Ishida: “Non-particle physics with intense muon
beams”, AIP Conf. Proc. 721, 77–82 (2004).
P. Strasser, K. Nagamine, T. Matsuzaki, K. Ishida, Y.
Matsuda, K. Itahashi, and M. Iwasaki: “Radioactive muonic atom studies with intense muon beams”,
AIP Conf. Proc. 721, 309–312 (2004).
N. Dinh Dang: “Reply to the Comment by A. Rabhi
on “Energies of the ground state and ﬁrst excited 0+
state in an exactly solvable pairing model” ”, Eur.
Phys. J. A 20, 281–282 (2004).
K. Morita, K. Morimoto, D. Kaji, H. Haba, E.
Ideguchi, R. Kanungo, K. Katori, H. Koura, H.
Kudo, T. Ohnishi, A. Ozawa, T. Suda, K. Sueki,
I. Tanihata, H. Xu, A. V. Yeremin, A. Yoneda, A.
Yoshida, Y. Zhao, and T. Zheng: “Production anddecay of the isotope 271 Ds(Z=110)”, Eur. Phys. J.
A 21, 257–263 (2004).
K. Morita, K. Morimoto, D. Kaji, H. Haba, E.
Ideguchi, J. L. Peter, R. Kanungo, K. Katori, H.
Koura, H. Kudo, T. Ohnishi, A. Ozawa, T. Suda,
K. Sueki, I. Tanihata, H. Xu, A. V. Yeremin, A.
Yoneda, A. Yoshida, Y. Zhao, T. Zheng, S. Goto,and F. Tokanai: “Production and decay properties309

of 272 111 and its daughter nuclei”, J. Phys. Soc. Jpn.
73, 1738–1744 (2004).
K. Morita, K. Morimoto, D. Kaji, T. Akiyama, S.
Goto, H. Haba, E. Ideguchi, R. Kanungo, K. Katori,
H. Koura, H. Kudo, T. Ohnishi, A. Ozawa, T. Suda,
K. Sueki, H. Xu, T. Yamaguchi, A. Yoneda, A.
Yoshida, and Y. Zhao: “Experiment on the synthesisof element 113 in the reaction 209 Bi(70 Zn,n)278 113”,
J. Phys. Soc. Jpn. 73, 2593–2596 (2004).
A. Yoshida, K. Morita, K. Morimoto, D. Kaji, T.
Kubo, Y. Takahashi, A. Ozawa, and I. Tanihata:“High-power rotating wheel targets at RIKEN”,
Nucl. Instrum. Methods Phys. Res. A 521, 65–71(2004).
Y. Ishida, M. Wada, Y. Matsuo, I. Tanihata, A.
Casares, and H. Wollnik: “A time-of-ﬂight mass
spectrometer to resolve isobars”, Nucl. Instrum.
Methods Phys. Res. B 219/220, 468–472 (2004).
C. Signorini, A. Yoshida, Y. Watanabe, D. Pierroutsakou, L. Stroe, T. Fukuda, M. Mazzocco, N.
Fukuda, Y. Mizoi, M. Ishihara, H. Sakurai, A. DiazTorres, and K. Hagino: “Subbarrier fusion in thesystems 11,10 Be+209 Bi”, Nucl. Phys. A 735, 329–
344 (2004).
R. Kanungo: “Two-proton halo in 17 Ne”, Nucl. Phys.
A 738, 293–297 (2004).
S. V. Stepantsov, M. Golovkov, A. Fomichev, A.
Rodin, S. Sidorchuk, R. Slepnev, G. Ter-Akopian,
M. Chelnokov, V. Gorshkov, Y. T. Oganessian, R.
Wolski, A. A. Korsheninnikov, E. Nikolski, and I.
Tanihata: “5 H and 5 He nuclear systems studied bymeans of the 6 He+2 H reaction”, Nucl. Phys. A 738,
436–439 (2004).
H. Jeppesen, R. Kanungo, B. A. Ibrahim, S. Adhikari,
M. Chiba, D. Fang, N. Iwasa, K. Kimura, K. Maeda,
S. Nishimura, T. Ohnishi, A. Ozawa, C. Samanta, T.
Suda, T. Suzuki, I. Tanihata, Q. Wang, C. Wu, Y.
Yamaguchi, K. Yamada, A. Yoshida, and T. Zheng:“One- and two-proton removal from 15 O”, Nucl.
Phys. A 739, 57–66 (2004).
M. Chiba, R. Kanungo, B. A. Ibrahim, S. Adhikari,
D. Fang, N. Iwasa, K. Kimura, K. Maeda, S.
Nishimura, T. Ohnishi, A. Ozawa, C. Samanta, T.
Suda, T. Suzuki, I. Tanihata, Q. Wang, C. Wu, Y.
Yamaguchi, K. Yamada, A. Yoshida, and T. Zheng:“Neutron removal studies on 19 C”, Nucl. Phys. A
741, 29–41 (2004).
S. Sidorchuk, D. Bogdanov, A. Fomichev, M.
Golovkov, Y. Oganessian, A. Rodin, R. Slepnev,
S. Stepantsov, G. Ter-Akopian, R. Wolski, A.
A. Korsheninnikov, E. Nikolski, A. Yukhimchuk,
V. Perevozchikov, Y. Vinogradov, F. Hanappe,
T. Materna, L. Stuttge, A. Ninane, P. RousselChomaz, and W. Mittig: “Experimental study of 4 H
in the reactions 2 H(t,p) and 3 H(t,d)”, Phys. Lett. B
594, 54–60 (2004).
K. Iida and K. Oyamatsu: “Surface tension in a com-310

pressible liquid-drop model: Eﬀects on nuclear density and neutron skin thickness”, Phys. Rev. C 69,
037301-1–037301-4 (2004).
A. Kohama, K. Iida, and K. Oyamatsu: “Nuclear radius deduced from proton diﬀraction by a black nucleus”, Phys. Rev. C 69, 064316-1–064316-4 (2004).
T. Matsuura, K. Iida, T. Hatsuda, and G. Baym:“Thermal ﬂuctuations of gauge ﬁelds and ﬁrst orderphase transitions in color superconductivity”, Phys.
Rev. D 69, 074012-1–074012-10 (2004).
K. Iida, T. Matsuura, M. Tachibana, and T. Hatsuda:“Melting pattern of diquark condensates in quark
matter”, Phys. Rev. Lett. 93, 132001-1–132001-4(2004).
A. Kohama: “Determination of matter surface distribution of neutron-rich nuclei ”, Proc. Int. Symp. on
A New Era of Nuclear Structure Physics (NENS03),(Niigata University), Kurokawa-cho, Niigata Pref.,2003–11, edited by Y. Suzuki and others, World Scientiﬁc, Singapore, pp. 272–276 (2004).
K. Iida, G. Baym, T. Matsuura, and T. Hatsuda:“Ginzburg-Landau approach to color superconductivity”, Prog. Theor. Phys. Suppl., No. 153, pp. 230–
240 (2004).
T. Matsuzaki, K. Nagamine, K. Ishida, N. Kawamura,
Y. Matsuda, H. Imao, M. Iwasaki, S. Nakamura, M.
Kato, H. Sugai, M. Tanase, K. Kudo, N. Takeda, andG. H. Eaton: “Strong n-α correlations observed inmuon catalyzed t-t fusion reactions”, Prog. Theor.
Phys. Suppl., No. 154, pp. 225–232 (2004).
N. Kawamura, K. Nagamine, T. Matsuzaki, K. Ishida,
S. Nakamura, Y. Matsuda, M. Tanase, M. Kato,
H. Sugai, K. Kudo, N. Takeda, and G. H. Eaton:“Anomalous temperature-dependent phenomena ofmuon catalyzed fusion in solid deuterium and tritium mixtures”, Prog. Theor. Phys. Suppl., No. 154,
pp. 233–240 (2004).
S. Ozawa and M. Hamagaki: “Preparation of selfsupporting boron ﬁlms by sputtering with electronbeam-excited plasma”, Vacuum 74, 417–421 (2004).

3. Atomic and solid-state physics
F. L. Pratt, S. J. Blundell, T. Jestadt, B. W. Lovett,
R. M. Macrae, and W. Hayes: “Muon radical states
in some electron donor and acceptor molecules”,
Magn. Reson. Chem. 38, S27–S32 (2000).
B. Webster and R. M. Macrae: “A theoretical investigation of the eﬀect of a sodium cation on the
proton-electron hyperﬁne coupling constants of thecyclohexadienyl radical and some consequences forthe muonium-substituted cyclohexadienyl radical,
C6 H6 Mu, formed in zeolites”, Physica B 289/290,
598–602 (2000).
R. M. Macrae, I. D. Reid, J.-U. von Schutz, and
K. Nagamine: “Order-disorder transition in anthracene/tetracyanobenzene probed by muonium-substituted radicals”, Physica B 289/290, 616–619(2000).
Y. Iwai, Y. Kanai, H. Oyama, K. Ando, H.
Masuda, K. Nishio, M. Nakao, K. Komaki, and Y.
Yamazaki: “High-resolution soft X-ray spectroscopyof 2.3 keV/u N7+ ions through a highly ordered Au
microcapillary target”, At. Collision Res. Jpn., No.
28, pp. 27–28 (2002).
Y. Nakai, Y. Kanai, Y. Iwai, K. Nishio, and H.
Masuda: “Coincidence measurement of L X-ray andﬁnal charge state of Ar ions transmitted through a
microcpaillary”, At. Collision Res. Jpn., No. 28, pp.
42–43 (2002).
Y. Chimi, A. Iwase, N. Ishikawa, and T. Kambara:“Defect production induced by electronic excitationin iron”, Nucl. Instrum. Methods Phys. Res. B 193,
248–252 (2002).
N. Ishikawa, A. Iwase, Y. Chimi, O. Michikami, H.
Wakana, T. Hashimoto, T. Kambara, C. Mueller,
and R. Neumann: “Se -scaling of lattce parameter change in high ion-velocity region (v ≥ 2.6 ×
109 cm/s) in ion-irradiated EuBa2 Cu3 Oy ”, Nucl. Instrum. Methods Phys. Res. B 193, 278–282 (2002).
Y. Iwai, Y. Kanai, Y. Nakai, T. Ikeda, H. Oyama, K.
Ando, H. Masuda, K. Nishio, H. Torii, K. Komaki,
and Y. Yamazaki: “High-resolution soft X-ray spectroscopy of slow highly charged ions transmitted
through a Ni microcapillary target using a single
photon counting method”, At. Collision Res. Jpn.,
No. 29, pp. 19–20 (2003).
Y. Kanai, Y. Nakai, Y. Iwai, T. Ikeda, K. Nishio,
H. Masuda, and Y. Yamazaki: “Coincidence measurements of X-rays and ﬁnal charge state of highly
charged ions transmitted through a microcapillary”,
At. Collision Res. Jpn., No. 29, pp. 25–26 (2003).
F. Ono, Y. Hamatani, Y. Mukumoto, S. Komatsu,
N. Ishikawa, Y. Chimi, A. Iwase, T. Kambara, C.
Mueller, and R. Neumann: “Modiﬁcation of Fe-Ni
Invar alloys by high-energy ion beams”, Nucl. Instrum. Methods Phys. Res. B 206, 295–298 (2003).
A. Iwase, Y. Hamatani, Y. Mukumoto, N. Ishikawa,Y. Chimi, T. Kambara, C. Mueller, R. Neumann,and F. Ono: “Anomalous shift of Curie temperaturein iron-nickel Invar alloys by high-energy heavy ion
irradiation”, Nucl. Instrum. Methods Phys. Res. B
209, 323–328 (2003).
R. Kadono, R. M. Macrae, and K. Nagamine: “Charge
dynamics of muonium centers in Si revealed by photoinduced muon spin relaxation”, Phys. Rev. B 68,
245204-1–245204-17 (2003).
P. Bakule and E. Morenzoni: “Generation and applications of slow polarized muons”, Contemp. Phys.
45, 203–225 (2004).
E. Yagi, T. Iwata, T. Urai, and K. Ogiwara: “Channelling studies on the lattice location of B atoms ingraphite”, J. Nucl. Mater. 334, 9–12 (2004).
N. Oshima, M. Niigaki, M. Inoue, T. M. Kojima, A.

Mohri, Y. Kanai, Y. Nakai, K. Komaki, and Y.
Yamazaki: “Project to produce cold highly charged
ions using positron and electron cooling techniques”,
J. Phys.: Con. Ser. 2, 127–133 (2004).
A. Igarashi and I. Shimamura: “Time-delay matrix
analysis of resonances: application to the positronium negative ion”, J. Phys. B 37, 4221–4237 (2004).
Y. Matsuda and Y. Miyake: “Ultra slow muon beamleads to novel applications of the µSR technique”,
Kotai Butsuri 39, 599–605 (2004).
N. Yamanaka, Y. Kino, Y. Takano, H. Kudo, and A.
Ichimura: “Direct positron annihilation and positronium formation”, Mater. Sci. Forum 445/446, 449–
451 (2004).
Y. Fukuyama, Y. Moriwaki, and Y. Matsuo: “Laserinduced ﬂuorescence spectra of Ba+∗ -He exciplexes
produced in cold He GAS”, Phys. Rev. A 69,
042505-1–042505-6 (2004).
A. Igarashi and I. Shimamura: “Stable complexrotation eigenvalues that correspond to no full resonances in scattering: Examples in positron scattering by the helium ion ”, Phys. Rev. A 70, 0127061–012706-5 (2004).
Y. Morishita, R. Hutton, H. Torii, K. Komaki, T.
Brage, K. Ando, K. Ishii, Y. Kanai, H. Masuda, M.
Sekiguchi, F. B. Rosmej, and Y. Yamazaki: “Direct observation of the initial-state distribution of
the ﬁrst electron transferred to slow highly charged
ions interacting with a metal surface”, Phys. Rev. A
70, 012902-1–012902-6 (2004).
H. Higaki, N. Kuroda, Y. K. Franzen, Z. Wang, M.
Hori, A. Mohri, K. Komaki, and Y. Yamazaki: “Radial compression of protons and H3 + ions in a multiring trap for the production of ultralow energy
antiproton beams”, Phys. Rev. E 70, 026501-1–
026501-5 (2004).
N. Oshima, T. M. Kojima, M. Niigaki, A. Mohri,
K. Komaki, and Y. Yamazaki: “New scheme forpositron accumulation in ultrahigh vacuum”, Phys.
Rev. Lett. 93, 195001-1–195001-4 (2004).
Y. Yamazaki: “Intense ultra slow p̄ beam and its application”, Phys. Scr. T 110, 286–291 (2004).
N. Nakamura, Y. Nakai, Y. Kanai, K. Komaki, A.
Endo, and Y. Yamazaki: “Compact electron beam
ion source with high-TC bulk superconductors”,
Rev. Sci. Instrum. 75, 3034–3038 (2004).

4.

Radiochemistry, radiation chemistry, and radiation biology

M. Suzuki, C. Tsuruoka, T. Kanai, T. Kato, F.
Yatagai, and M. Watanabe: “Qualitative and quantitative diﬀerence in mutation induction between
carbon- and neon-ion beams in normal human cells”,
Biol. Sci. Space 17, 302–306 (2003).
H. Haba, K. Akiyama, K. Tsukada, M. Asai, A.
Toyoshima, T. Yaita, M. Hirata, K. Sueki, and Y.

311

Nagame: “Chloride complexation of rutherfordium:
X-ray absorption ﬁne structure spectroscopy of Zr
and Hf in HCl”, Advances in Nuclear and Radiochemistry (Reihe Allgemeines und Interdisziplinares
Vol. 3), (Forschungszentrum Julich), Aachen, Germany, 2004–8〜9, Forschungszentrum Julich, Julich,
pp. 150–152 (2004).
A. Toyoshima, K. Tsukada, M. Asai, H. Haba, K.
Akiyama, I. Nishinaka, D. Saika, K. Matsuo, W.
Sato, H. Ishidu, M. Ito, J. Saito, S. Goto, H.
Kudo, H. Kikunaga, N. Kinoshita, C. Kato, A.
Yokoyama, K. Sueki, Y. Nagame, and A. Shinohara:“Elution behavior of rutherfordium (Rf) in anionexchange chromatography in a hydroﬂuoric acidsystem”, Advances in Nuclear and Radiochemistry (Reihe Allgemeines und Interdisziplinares Vol.
3), (Forschungszentrum Julich), Aachen, Germany,
2004–8〜9, Forschungszentrum Julich, Julich, pp.
153–154 (2004).
K. Tsukada, H. Haba, M. Asai, A. Toyoshima, K.
Akiyama, I. Nishinaka, M. Hirata, K. Hashimoto,S. Ichikawa, Y. Nagame, K. Yasuda, Y. Miyamoto,Y. Tani, H. Hasegawa, W. Sato, A. Shinohara, S.
Goto, M. Ito, J. Saito, H. Ishidu, H. Kudo, Y.
Oura, H. Nakahara, K. Sueki, N. Kinoshita, H.
Kikunaga, and A. Yokoyama: “Sorption on anionexchange resin of dubnium and its homologues in
HF solution”, Advances in Nuclear and Radiochemistry (Reihe Allgemeines und Interdisziplinares Vol.
3), (Forschungszentrum Julich), Aachen, Germany,
2004–8〜9, Forschungszentrum Julich, Julich, pp.
155–157 (2004).
H. Haba, K. Igarashi, D. Kaji, R. Hirunuma,
and S. Enomoto: “Development of a gas-jetcoupled multitarget system for multitracer production”, Advances in Nuclear and Radiochemistry (Reihe Allgemeines und Interdisziplinares Vol.
3), (Forschungszentrum Julich), Aachen, Germany,
2004–8〜9, Forschungszentrum Julich, Julich, pp.
333–335 (2004).
S. Komiyama, S. Taniguchi, Y. Matsumoto, E. Tsunoda, T. Ohto, Y. Suzuki, L. H. Yin, M. Tomita,
A. Enomoto, A. Morita, T. Suzuki, K. Ohtomo,
Y. Hosoi, and N. Suzuki: “Potentiality of DNAdependent protein kinase to phosphorylate Ser46
of human p53”, Biochem. Biophys. Res. Commun.
323, 816–822 (2004).
H. Haba and Y. Nagame: “Chemical Properties of Superheavy Elements”, Gendai Kagaku 12, No. 405,
pp. 32–38 (2004).
H. Haba, K. Tsukada, M. Asai, A. Toyoshima, K.
Akiyama, I. Nishinaka, M. Hirata, T. Yaita, S.
Ichikawa, Y. Nagame, K. Yasuda, Y. Miyamoto, T.
Kaneko, S. Goto, S. Ono, T. Hirai, H. Kudo, M.
Shigekawa, A. Shinohara, Y. Oura, H. Nakahara, K.
Sueki, H. Kikunaga, N. Kinoshita, N. Tsuruga, A.
Yokoyama, M. Sakama, S. Enomoto, M. Schaedel,

312

W. Bruechle, and J. V. Kratz: “Fluoride complexation of element 104, rutherfordium”, J. Am. Chem.
Soc. 126, 5219–5224 (2004).
K. Igarashi, H. Inage, Y. Nakanishi, T. Nakadai,
M. Okayasu, R. Hirunuma, S. Enomoto, and S.
Kimura: “Eﬃcacy of sodium iron etylenediaminetetraacetic acid as a food fortiﬁer for improving theiron-deﬁcient status of anemic rats”, J. Jpn. Soc.
Nutr. Food Sci. 57, 89–97 (2004).
T. Abe, Y. Miyazawa, H. Saito, Y. Yamamoto, H.
Ryuto, and N. Fukunishi: “Development of plantmutational breeding by heavy ions”, JAERI-Conf,
No. 2004-001, pp. 44–47 (2004).
H. Haba: “Chemistry of the heaviest elements in
RIKEN: Present status and future plans”, JAERIConf, No. 2004-004, pp. 105–118 (2004).
H. Haba, K. Morita, S. Enomoto, K. Morimoto,
D. Kaji, and Y. Nagame: “Development of anovel heavy element chemistry apparatus using the
RIKEN gas-ﬁeld recoil separator as a pre-separator”,
JAERI-Conf, No. 2004-014, pp. 67–71 (2004).
H. Haba, K. Tsukada, M. Asai, A. Toyoshima, K.
Akiyama, I. Nishinaka, M. Hirata, T. Yaita, S.
Ichikawa, Y. Nagame, K. Yasuda, Y. Miyamoto, T.
Kaneko, S. Goto, S. Ono, T. Hirai, H. Kudo, M.
Shigekawa, A. Shinohara, Y. Oura, H. Nakahara, K.
Sueki, H. Kikunaga, N. Kinoshita, N. Tsuruga, A.
Yokoyama, M. Sakama, S. Enomoto, W. Bruechle,
M. Schaedel, and J. V. Kratz: “Fluoride complexation of Rf”, JAERI-Rev., No. 2004-027, pp. 43–44(2004).
K. Tsukada, A. Toyoshima, M. Asai, H. Haba, K.
Akiyama, I. Nishinaka, Y. Nagame, D. Saika, K.
Matsuo, W. Sato, A. Shinohara, H. Ishizu, M.
Ito, J. Saito, S. Goto, H. Kudo, H. Kikunaga,
N. Kinoshita, C. Kato, A. Yokoyama, and K.
Sueki: “Anion-exchange chromatographic behaviorof rutherfordium(Rf) in hydroﬂuoric acid”, JAERIRev., No. 2004-027, pp. 45–46 (2004).
H. Haba: “Chemical properties of the super heavy element 112”, Kagaku to Kogyo 57, 440 (2004).
T. Abe: “Development of mutant induction method
using heavy-ion irradiation”, Noukouken Tsushin 4,
No. 132, pp. 2–8 (2004).
T. Abe: “Application of ion beam irradiation for mutation breeding”, Nuclear Viewpoints 50, No. 5, pp.
42–45 (2004).
N. Yamanaka, Y. Kino, and A. Ichimura: “Wavepacket analysis of multichannel resonances inpositron scattering by a helium ion”, Phys. Rev. A
70, 62701-1–062701-5 (2004).
T. Kagawa, M. Kasahara, T. Abe, S. Yoshida, and M.
Wada: “Function analysis of phototropin2 using fern
mutants deﬁcient in blue light-induced chloroplast
avoidance movement”, Plant Cell Physiol. 45, 416–
426 (2004).
H. L. Yin, Y. Suzuki, Y. Matsumoto, M. Tomita, Y.

Furusawa, A. Enomoto, A. Morita, M. Aoki, F.
Yatagai, T. Suzuki, Y. Hosoi, K. Ohtomo, and N.
Suzuki: “Radiosensitization by hyperthermia in thechicken B-lymphocyte cell line DT40 and its derivatives lacking nonhomologous end joining and/or homologous recombination pathways of DNA doublestrand break repair”, Radiat. Res. 162, 433–441(2004).

5. Material Analysis
Z. Liu, J. Kawamura, M. Nagasono, K. Maeda, and
J. Kawai: “Determination of the structure of boron
subphosphide by P Kβ X-ray ﬂuorescence spectra”,
J. Electron Spectrosc. Relat. Phenom. 135, 73–81(2004).
K. Maeda, H. Hamanaka, M. Maeda, K. Ogiwara, andK. Hasegawa: “Time-resolved chemical state analysis by highly sensitive high-resolution PIXE”, Proc.
10th Int. Conf. on Particle Induced X-ray Emission
and its Analytical Applications (PIXE 2004), (Jozef
Stefan Institute, University of Ljubljana and others),
Portoroz, Slovenia, 2004–6, edited by M. Budnarand M. Kavcic, Jozef Stefan Institute, Ljubljana, pp.
815.1–815.3 (2004).

6. RIKEN-BNL Collaboration
Y. Goto and PHENIX Collaboration: “Prospects ofthe gluon polarization measurement at PHENIX”,
AIP Conf. Proc. 675, 493–503 (2003).
Y. Akiba and PHENIX Collaboration: “Silicon vertex detector upgrade for the PHENIX experiment
at RHIC”, AIP Conf. Proc. 698, 785–788 (2003).
Y. Goto and PHENIX Collaboration: “Neutral pionmeasurements in polarized proton collisions fromPHENIX at RHIC”, Nucl. Phys. A 721, 360c–363c(2003).
Y. Akiba and H. Hamagaki: “The beginning ofhigh energy nucleus-nucleus collision experiment at
RHIC”, Butsuri 59, 291–299 (2004).
J. Tojo, K. Aoki, H. Enyo, Y. Fukao, Y. Goto, J.
Heuser, Z. Li, H. Onishi, H. Okada, V. Radeka,
V. Rykov, N. Saito, F. Sakuma, M. Sekimoto, K.
Tanida, M. Togawa, and Y. Watanabe: “Development of a novel silicon stripixel detector for RHICPHENIX detector upgrade”, IEEE Trans. Nucl. Sci.
51, 2337–2340 (2004).
T. Tominaka: “Vector potential for a single helical current condutor”, Nucl. Instrum. Methods Phys. Res.
A 523, 1–8 (2004).

Z. Li, H. Enyo, Y. Goto, V. Radeka, R. H.
Beuttenmuller, W. Chen, D. Elliott, Y. H. Guo,
T. Kawabata, M. Togawa, N. Saito, V. Rykov, K.
Tanida, and J. Tojo: “Development of 2nd prototype of novel silicon stripixel detector for PHENIX
upgrade”, Nucl. Instrum. Methods Phys. Res. A
535, 404–409 (2004).
M. Hirai: “Uncertainty of polarized gluon distribution from prompt photon production”, Phys. Lett.
B 596, 287–292 (2004).
M. Hirai, S. Kumano, and T. Nagai: “Nuclear parton distribution functions and their uncertainties”,
Phys. Rev. C 70, 044905-1–044905-10 (2004).
M. Hirai, S. Kumano, and N. Saito: “Determinationof polarized parton distribution functions and theiruncertainties”, Phys. Rev. D 69, 054021-1–05402110 (2004).
T. Ikeda: “Eﬀect of memory on relaxation in a scalarﬁeld theory”, Phys. Rev. D 69, 105018-1–105018-10(2004).
H. Fujii and M. Ohtani: “Sigma and hydrodynamic
modes along the critical line”, Phys. Rev. D 70,
014016-1–014016-18 (2004).
Y. Hidaka, O. Morimatsu, T. Nishikawa, and M.
Ohtani: “Two-pion bound state in the sigma channel
at ﬁnite temperature”, Phys. Rev. D 70, 076001-1–
076001-5 (2004).
M. Ohtani and K. Ohta: “Skyrmions coupled to theelectromagnetic ﬁeld via the gauged Wess-Zuminoterm”, Phys. Rev. D 70, 096014-1–096014-7 (2004).
Y. Akiba: “Experimental results from RHIC”, Proc.
Int. Conf. on Color Conﬁnement and Hadronsin Quantum Chromodynamics: Conﬁnement 2003,(Tokyo Institute of Technology and RIKEN), Wako,
2003–7, World Scientiﬁc, Singapore, pp. 361–372(2004).
H. Fujii and M. Ohtani: “Soft modes at the critical end
point in the chiral eﬀective models”, Prog. Theor.
Phys. Suppl., No. 153, pp. 157–164 (2004).
A. Iwazaki, O. Morimatsu, T. Nishikawa, and M.
Ohtani: “Quantum Hall states of gluons in quark
matter”, Prog. Theor. Phys. Suppl., No. 153, pp.
198–203 (2004).
M. Ohtani and H. Fujii: “Sigma and hydrodynamic
modes near the critical end point”, Prog. Theor.
Phys. Suppl., No. 156, pp. 167–168 (2004).
T. Nishikawa, A. Iwazaki, O. Morimatsu, and M.
Ohtani: “Color ferromagnetic states and quantum
hall states of gluons in quark matter”, Prog. Theor.
Phys. Suppl., No. 156, pp. 178–179 (2004).

313

VII. LIST OF PREPRINTS
2004
RIKEN-AF-NP
456 M. Hirai and K. Sudoh: “Eﬀect of polarized gluon distribution on π 0 spin asymmetry”
457 T. Yamazaki, A. Dote, and Y. Akaishi: “Quest for dense and cold nuclear bound systems mediated by K−
mesons”
458 Y. Yanagisawa, S. Kubono, T. Teranishi, K. Ue, S. Michimasa, M. Notani, J. J. He, Y. Ohshiro, S. Shimoura,
S. Watanabe, N. Yamazaki, H. Iwasaki, S. Kato, T. Kishida, T. Morikawa, and Y. Mizoi: “Low-energy
radioisotope beam separator CRIB”
459 Y. Kondo, T. Nakamura, N. Aoi, H. Baba, D. Bazin, N. Fukuda, T. Gomi, H. Hasegawa, N. Imai, M. Ishihara,
T. Kobayashi, T. Kubo, M. Miura, T. Motobayashi, A. Saito, H. Sakurai, S. Shimoura, T. Sugimoto, K.
Watanabe, Y. X. Watanabe, T. Yakushiji, Y. Yanagisawa, and K. Yoneda: “In-beam γ-ray spectroscopy ofthe neutron-rich boron isotopes 15,17 B via inelastic scattering on 12 C”
460 N. Dinh Dang: “Nuclear giant resonances”
461 N. Dinh Dang: “Particle-number conservation within self-consistent random-phase approximation”

RIKEN-AF-AC
44 H. Amemiya, H. Tsutsui, and T. Katayama: “Electron cooling by electron beam of ﬂattened velocity
distribution with variable coulomb logarithm”
45 M. Nishiura, T. Tanabe, T. Katayama, E. Syresin, A. Sidorin, A. Smirnov, and I. Watanabe: “Study on
the electron cooler for the accumulator cooler ring at RIKEN”
46 M. Serata, M. Takanaka, T. Ohkawa, M. Watanabe, and T. Katayama: “Design and bench test of a planner
slotline pick-up for stochastic cooling”

314

VIII. PAPERS PRESENTED AT MEETINGS
1. Accelerator
physics

development

andaccelerator

M. Komiyama, I. Yokoyama, M. Nagase, M. Fujimaki,
T. Tanabe, M. Kase, and J. Odagiri: “Current status of the control system for the RIKEN Accelerator Research Facility”, 9th Int. Conf. on Accelerator
and Large Experimental Physics Control Systems(ICALEPCS 2003), (Pohang University of Scienceand Technology), Gyeongju, Korea, Oct. (2003).
M. Komiyama: “Device interface module at RIKEN”,
EPICS Collaboration Meet., Gyeongju, Korea, Oct.
(2003).
M. Komiyama, M. Kase, T. Tanabe, M. Fujimaki, M.
Nagase, I. Yokoyama, and J. Odagiri: “Expansionof the control system for RARF”, 14th Symp. on
Accelerator Science and Technology (SAST03), (TheJapanese Accelerator Researchers Association and
KEK), Tsukuba, Nov. (2003).
T. Watanabe: “A highly sensitive current and position
monitor with HTS SQUIDs and an HTS magnetic
shield”, Nihon Gakujyutu Shinkoukai Choudendou
Electronics Dai 146 Iinkai, Kouseinou SQUID System Bunkakai, Dai 59 Kai Kenkyuukai, Japan, May(2004).
J. Ohnishi, T. Mitsumoto, A. Goto, M. Kase, M.
Nagase, and Y. Yano: “Construction status of themagnet system for the RIKEN intermediate-stage
ring cyclotron”, 1st Ann. Meet. of Particle Accelerator Soc. of Japan/29th Linear Accelerator Meet. inJapan, Funabashi, Aug. (2004).
A. Goto: “Study on accelerators at RIKEN”, Workshop on Research and Development of Accelerators
in Atomic Energy Science, (Kyoto University Research Reactor Institute), Kyoto, Aug. (2004).
T. Watanabe, T. Ikeda, M. Kase, Y. Yano, S.
Watanabe, Y. Sasaki, and T. Kawaguchi: “Development of a highly sensitive current and position
monitor with HTS SQUIDs and an HTS magnetic
shield”, 17th Int. Conf. on Cyclotrons and Their Applications (Cyclotrons 2004), (RIKEN), Tokyo, Oct.
(2004).
A. Goto, Y. Chiba, N. Fukunishi, O. Kamigaito,
M. Kase, S. Kohara, N. Sakamoto, Y. Yano, T.
Katayama, T. Teranishi, and S. Watanabe: “Status of the ﬂattop acceleration system in the RIKEN
AVF cyclotron”, 17th Int. Conf. on Cyclotrons andTheir Applications (Cyclotrons 2004), (RIKEN),
Tokyo, Oct. (2004).
O. Kamigaito, T. Chiba, Y. Chiba, M. Fujimaki, A.
Goto, M. Hemmi, E. Ikezawa, M. Kase, S. Kohara,
Y. Miyazawa, N. Fukunishi, N. Sakamoto, and Y.
Yano: “Upgrade of RILAC injector”, 17th Int. Conf.
on Cyclotrons and Their Applications (Cyclotrons
2004), (RIKEN), Tokyo, Oct. (2004).

2.

Nuclear physics and nuclear instrumentation

H. Madokoro, T. Shimizu, and Y. Motizuki: “Eﬀects
of small-scale ﬂuctuations of neutrino ﬂux in supernova explosions”, IAU Colloq. 192 on Supernovae(10 years of SN1993J), Valencia, Spain, Apr. (2003).
A. Kohama, K. Iida, and K. Oyamatsu: “Fraunhofer
diﬀraction and nuclear matter radii”, 59th Ann.
Meet. of Physical Soc. of Japan, Fukuoka, Mar.
(2004).
Y. Motizuki: “Supernovae and solar activity enshrinedin Antarctic ice core”, Special Colloq. at Natl. Institute of Polar Research, Tokyo, Mar. (2004).
H. Ueno: “Measurements of nuclear moments: Current status and future trend”, Physics of Unstable
Nuclei: Past Decade and the Future, (RIBF-UEC
and RIKEN), Wako, June (2004).
Y. Ishida, M. Wada, Y. Matsuo, and H. Wollnik:“Precise mass measurement of unstable nuclei using a multi-reﬂection time-of-ﬂight mass spectrometer”, 52nd Ann. Conf. on Mass Spectrometry, (The
Mass Spectrometry Society of Japan), Nagoya, June
(2004).
K. Iida: “Ginzburg-Landau approach to color superconductivity”, University of Washington Institutefor Nuclear Theory Program (INT-04-1): QCD and
Dense Matter: From Lattices to Stars, Seattle, USA,
June (2004).
T. Gomi, T. Motobayashi, Y. Ando, N. Aoi, H.
Baba, K. Demichi, Z. Elekes, N. Fukuda, Z. Fulop,
U. Futakami, H. Hasegawa, Y. Higurashi, K. Ieki,
N. Imai, M. Ishihara, K. Ishikawa, N. Iwasa,
H. Iwasaki, S. Kanno, Y. Kondo, T. Kubo, S.
Kubono, M. Kunibu, K. Kurita, Y. Matsuyama, S.
Michimasa, T. Minemura, M. Miura, H. Murakami,
T. Nakamura, M. Notani, S. Ota, A. Saito, H.
Sakurai, M. Serata, S. Shimoura, T. Sugimoto,
E. Takeshita, S. Takeuchi, Y. Togano, K. Ue,
K. Yamada, Y. Yanagisawa, K. Yoneda, and A.
Yoshida: “Coulomb dissociation of 23 Al for the22
Mg(p,γ)23 Al reaction”, 8th Int. Symp. on Nuclei in the Cosmos (NIC8), (TRIUMF), Vancouver,
Canada, July (2004).
K. Ishida: “Muon catalyzed fusion”, 6th Int. Workshop
on Neutrino Factories and Superbeams (NuFact 04),
Osaka, July–Aug. (2004).
D. Tomono: “Muon lifetime measurement with pulsed
muon beam”, 6th Int. Workshop on Neutrino Factories and Superbeams (NuFact 04), Osaka, July–Aug.
(2004).
K. Morimoto: “Recent results of superheavy element
research using GARIS at RIKEN”, 3rd Workshop
on Recoil Separator for Superheavy Element Chemistry, (GSI), Darmstadt, Germany, Aug. (2004).
K. Yamada, T. Motobayashi, N. Aoi, H. Baba, K.

315

Demichi, Z. Elekes, J. D. Gibelin, T. Gomi, H.
Hasegawa, N. Imai, H. Iwasaki, S. Kanno, T.
Kubo, K. Kurita, Y. Matsuyama, S. Michimasa, T.
Minemura, M. Notani, T. Onishi, H. Ong, S. Ota,
A. Ozawa, A. Saito, H. Sakurai, S. Shimoura, E.
Takeshita, S. Takeuchi, M. Tamaki, Y. Togano, Y.
Yanagisawa, K. Yoneda, and I. Tanihata: “B(E2)measurement of the proton-rich 46 Cr,50 Fe, and 54 Ni
nuclei studied by Coulomb excitation”, 2004 Autumn Meet. of the Physical Soc. of Japan, Kochi
and Aomori, Sept. (2004).
M. Takashina: “Direct reaction dynamics of unstable
nucleus”, 2004 Autumn Meet. of the Physical Soc.
of Japan, Kochi and Aomori, Sept. (2004).
H. Masui: “Dynamics of halo nuclei, and the role of
the resonant and continuum states”, 2004 Autumn
Meet. of the Physical Soc. of Japan, Kochi and Aomori, Sept. (2004).
N. Aoi, W. F. Mueller, D. Bazin, M. D. Bowen, C.
M. Campbell, J. M. Cook, D. C. Dinca, A. Gade,
T. Glasmacher, T. Kubo, H. Iwasaki, H. Sakurai, T.
Motobayashi, T. Nakamura, H. Olliver, S. Takeuchi,
J. R. Teryy, H. Suzuki, and K. Yoneda: “Inelastic
scattering on 74 Ni”, 2004 Autumn Meet. of the Physical Soc. of Japan, Kochi and Aomori, Sept. (2004).
R. Mutou, J. Chiba, H. Enyo, Y. Fukao, H. Funahashi,
H. Hamagaki, M. Ieiri, M. Ishino, H. Kanda, M.
Kitaguchi, S. Mihara, T. Miyashita, K. Miwa, T.
Murakami, T. Nakura, M. Naruki, M. Nomachi,
K. Ozawa, F. Sakuma, O. Sasaki, M. Sekimoto,T. Tabaru, K. Tanaka, M. Togawa, S. Yamada,
S. Yokkaichi, and Y. Yoshimura: “Measurement of
in-medium mass modiﬁcation of vector mesons in
12 GeV p+A → ρ/ω/φ + X interactions (KEK-PS
E325)”, 2004 Autumn Meet. of the Physical Soc. ofJapan, Kochi and Aomori, Sept. (2004).
K. Ishida, K. Nagamine, T. Matsuzaki, N. Kawamura,
Y. Matsuda, M. Iwasaki, H. Imao, M. Kato, H.
Sugai, and G. H. Eaton: “Muon catalyzed fusion experiment in D-T system at RIKEN-RAL Muon Facility: magnetic ﬁeld eﬀect 2”, 2004 Autumn Meet.
of the Physical Soc. of Japan, Kochi and Aomori,Sept. (2004).
H. Imao, K. Nagamine, T. Matsuzaki, K. Ishida, N.
Kawamura, Y. Matsuda, A. Toyoda, M. Kato, H.
Sugai, A. Uritani, and H. Harano: “Ortho-para effect on µCF in condensed D2 ”, 2004 Autumn Meet.
of the Physical Soc. of Japan, Kochi and Aomori,Sept. (2004).
Y. Ishida, M. Wada, and H. Wollnik: “Precise massmeasurement of short-lived nuclei using a compact
time-of-ﬂight mass spectrometer”, 2004 Autumn
Meet. of the Physical Soc. of Japan, Kochi and Aomori, Sept. (2004).
K. Iida, A. Kohama, and K. Oyamatsu: “Reaction
cross section described by a “black” nucleus”, 2004
Autumn Meet. of the Physical Soc. of Japan, Kochi

316

and Aomori, Sept. (2004).
A. Kohama, K. Iida, and K. Oyamatsu: ““Black” nucleus picture and nuclear matter radii”, 2004 Autumn Meet. of the Physical Soc. of Japan, Kochi
and Aomori, Sept. (2004).
S. Michimasa, S. Shimoura, H. Iwasaki, M. Tamaki,
S. Ota, N. Aoi, H. Baba, N. Iwasa, S. Kanno,
S. Kubono, K. Kurita, M. Uesaka, T. Minemura,
T. Motobayashi, M. Notani, H. Ong, A. Saito, H.
Sakurai, S. Takeuchi, E. Takeshita, Y. Yanagisawa,
and A. Yoshida: “Study of single-particle states in
23
F using a proton transfer reaction”, 4th Int. Conf.
on Exotic Nuclei and Atomic Masses (ENAM 04),
Pine Mountain, USA, Sept. (2004).
Y. Ishida, M. Wada, and H. Wollnik: “A multireﬂection time-of-ﬂight mass spectrometer for massmeasurements of short-lived nuclei”, 18th Int. Conf.
on the Application of Accelerators in Research andIndustry (CAARI 2004), (American Physical Society), Fort Worth, USA, Oct. (2004).
H. Ueno: “Design of the beam transport line from IRC
to RIPS”, RIKEN Symp. on Research Projects Dedicated to RIPS in the RIBF Conﬁguration, Wako,
Oct. (2004).
N. Dinh Dang: “Nuclear giant resonances”, 9th Asia
Paciﬁc Physics Conf. (APPC 2004), (Association ofAsia Paciﬁc Physical Societies and others), Hanoi,
Vietnam, Oct. (2004).
T. Matsuzaki: “Recent researches at the RIKEN-RAL
Muon Facility; Muon catalyzed d-t fusion”, 9th Asia
Paciﬁc Physics Conf. (APPC 2004), (Association ofAsia Paciﬁc Physical Societies and others), Hanoi,
Vietnam, Oct. (2004).
K. Sekiguchi: “Nucleon-deuteron scattering at intermediate energies and three nucleon force”, Workshop on Light Ion and Polarization Phenomena 2004,(Tsukuba University), Tsukuba, Nov. (2004).
T. Gomi, T. Motobayashi, Y. Ando, N. Aoi, H.
Baba, K. Demichi, Z. Elekes, N. Fukuda, Z. Fulop,
U. Futakami, H. Hasegawa, Y. Higurashi, K. Ieki,
N. Imai, M. Ishihara, K. Ishikawa, N. Iwasa,
H. Iwasaki, S. Kanno, Y. Kondo, T. Kubo, S.
Kubono, M. Kunibu, K. Kurita, Y. Matsuyama, S.
Michimasa, T. Minemura, M. Miura, H. Murakami,
T. Nakamura, M. Notani, S. Ota, A. Saito, H.
Sakurai, M. Serata, S. Shimoura, T. Sugimoto,
E. Takeshita, S. Takeuchi, Y. Togano, K. Ue,
K. Yamada, Y. Yanagisawa, K. Yoneda, and A.
Yoshida: “Coulomb dissociation for astrophysics”,
Japanese-German Nuclear Structure and Astrophysics Workshop, (GSI and RIKEN), Darmstadt,
Germany, Dec. (2004).
A. Kohama, K. Iida, and K. Oyamatsu: “Extensive
view of nuclei in black sphere picture”, Workshop on
Recent Progress and Future Prospects of Few Body
System Physics, (RCNP), Osaka, Dec. (2004).
T. Gomi, T. Motobayashi, Y. Ando, N. Aoi, H.

Baba, K. Demichi, Z. Elekes, N. Fukuda, Z.
Fulop, U. Futakami, H. Hasegawa, Y. Higurashi,
K. Ieki, N. Imai, M. Ishihara, K. Ishikawa, N.
Iwasa, H. Iwasaki, S. Kanno, Y. Kondo, T.
Kubo, S. Kubono, M. Kunibu, K. Kurita, Y.
Matsuyama, S. Michimasa, T. Minemura, M. Miura,
H. Murakami, T. Nakamura, M. Notani, S. Ota,
A. Saito, H. Sakurai, M. Serata, S. Shimoura, T.
Sugimoto, E. Takeshita, S. Takeuchi, Y. Togano,
K. Ue, K. Yamada, Y. Yanagisawa, K. Yoneda,
and A. Yoshida: “Coulomb dissociation experiment for explosive hydrogen burning: study of the22
Mg(p,γ)23 Al reaction”, Nuclear Structure, Astrophysics and Reactions (NUSTAR 05), (University ofSurrey), Guildford, UK, Jan. (2005).

3. Atomic and solid-state physics
M. Hoshino, T. Kambara, Y. Kanai, S. Madzunokov,
R. Schuch, and Y. Yamazaki: “Multi-electron processes in close single collisions of slow highly charged
ions with atoms”, 28th Ann. Meet. of the Soc. for
Atomic Collision Research, Hachioji, Aug. (2003).
M. Hoshino, Y. Kanai, Y. Nakai, M. Kitajima, H.
Tanaka, and Y. Yamazaki: “State-selective angular distribution measurements of charge transfer processes for slow X4+ (X = C, N, O) - He collisions”,
28th Ann. Meet. of the Soc. for Atomic Collision
Research, Hachioji, Aug. (2003).
M. Fujiwara: “Confronting CPT with cold antihydrogen”, New Direction of Particle Physics (TEA03),(Yukawa Institute for Theoretical Physics), Kyoto,
Oct. (2003).
N. Oshima, T. M. Kojima, M. Niigaki, M. Inoue, K.
Komaki, and Y. Yamazaki: “Plans for improvement of positron accumulation eﬃciency”, Specialist Research Meet. on Positron Beam Techniques
and Their Applications, (Research Reactor Institute, Kyoto University), Kyoto, Dec. (2003).
Y. Kanai: “Development of a new method to preparea polarized antihydrogen”, RIKEN Symp. on Studies on Condensed Matter Physics, Atomic Physics,
Nuclear Chemistry, and Biology and Medicine Using
RIKEN Accelerators, Wako, Jan. (2004).
N. Oshima: “Development of a positron accumulator for cooling of highly charged ions”, RIKEN
Symp. on Int. Workshop on Atomic Collisions of
Slow/Trapped Highly-Charged Ions, Wako, Feb.
(2004).
M. Hoshino: “The study of double-electron capture
processes for C4+ - He collisions in the energy
range of 60–110 eV/q”, RIKEN Symp. on Int. Workshop on Atomic Collisions of Slow/Trapped HighlyCharged Ions, Wako, Feb. (2004).
M. Wada: “Universal slow radioactive beams and theirapplication”, RIKEN Symp. on Int. Workshop on
Atomic Collisions of Slow/Trapped Highly-Charged

Ions, Wako, Feb. (2004).
S. Masugi, A. Ishikawa, T. Muranaka, T. Azuma, C.
Kondo, A. Hatakeyama, K. Komaki, Y. Yamazaki,
E. Takada, and T. Murakami: “Channeling and resonant coherent excitation of high energetic ions using thin crystals”, 59th Ann. Meet. of Physical Soc.
of Japan, Fukuoka, Mar. (2004).
Y. Kanai, Y. Nakai, Y. Iwai, T. Ikeda, H. Masuda,
K. Nishio, and Y. Yamazaki: “Coincidence measurements of L X-rays and ﬁnal charge state of Ar
ions transmitted through a microcapillary (2)”, 59th
Ann. Meet. of Physical Soc. of Japan, Fukuoka, Mar.
(2004).
M. Niigaki, M. Inoue, N. Oshima, T. M. Kojima,
A. Mohri, and Y. Yamazaki: “Cooling of highlycharged ions by utilizing a high density electron
plasma: An attempt”, 59th Ann. Meet. of PhysicalSoc. of Japan, Fukuoka, Mar. (2004).
N. Yamanaka and Y. Kino: “Development of a timedependent coupled channel method and its application to antiproton-hydrogen atom collisions”, 59th
Ann. Meet. of Physical Soc. of Japan, Fukuoka, Mar.
(2004).
N. Kuroda, H. Torii, M. Inoue, A. Mohri, D. Barna,
K. Komaki, and Y. Yamazaki: “Diagnostics ofantiproton-electron mixed plasma and extraction ofultra-slow antiprotons of from a strong magnetic
ﬁeld”, 59th Ann. Meet. of Physical Soc. of Japan,
Fukuoka, Mar. (2004).
Y. Nakai, M. Wada, T. Kambara, I. Katayama, and Y.
Yamazaki: “Electronic response in nuclear decay of
an ion with an unstable nucleus trapped in vacuum”,
59th Ann. Meet. of Physical Soc. of Japan, Fukuoka,
Mar. (2004).
A. Mohri, Y. Kanai, Y. Nakai, and Y. Yamazaki: “Experiment on electron plasma conﬁnement in a cusped
high magnetic ﬁeld and an electric octupole”, 59th
Ann. Meet. of Physical Soc. of Japan, Fukuoka, Mar.
(2004).
M. Niigaki, T. M. Kojima, N. Oshima, A. Mohri, M.
Inoue, K. Komaki, and Y. Yamazaki: “Formation ofa high-density electron plasma in a multi-ring trap”,
59th Ann. Meet. of Physical Soc. of Japan, Fukuoka,
Mar. (2004).
M. Fujiwara: “Fundamental physics with cold antihydrogen”, 59th Ann. Meet. of Physical Soc. of Japan,
Fukuoka, Mar. (2004).
M. Inoue, N. Oshima, T. M. Kojima, M. Niigaki, A.
Mohri, K. Komaki, and Y. Yamazaki: “Improvement of a positron accumulator”, 59th Ann. Meet.
of Physical Soc. of Japan, Fukuoka, Mar. (2004).
H. Kanamitsu, S. Komatsu, Y. Hamatani, A. Iwase,
N. Ishikawa, Y. Chimi, T. Kambara, and F. Ono:
“Ion induced Fe-Pt alloy magnetic property change”,
59th Ann. Meet. of Physical Soc. of Japan, Fukuoka,
Mar. (2004).
A. Igarashi and I. Shimamura: “Positron scattering317

by the He ion: Examples of complex rotation eigenvalues corresponding to no full resonances”, 59th
Ann. Meet. of Physical Soc. of Japan, Fukuoka, Mar.
(2004).
T. Kambara, Y. Nakai, T. Ikeda, Y. Kanai, N.
Fukunishi, K. Komaki, T. Azuma, C. Kondo, and Y.
Yamazaki: “Resonant Coherent Excitation (RCE)observed for 2s electrons of Li-like Fe and Ni ions”,
59th Ann. Meet. of Physical Soc. of Japan, Fukuoka,
Mar. (2004).
C. Kondo, T. Muranaka, S. Masugi, A. Ishikawa, T.
Azuma, A. Hatakeyama, K. Komaki, Y. Yamazaki,
E. Takada, and T. Murakami: “Resonant coherent
excitation of relativistic highly charged ion 4: Stark
eﬀect of He-like Ar and Fe ions”, 59th Ann. Meet.
of Physical Soc. of Japan, Fukuoka, Mar. (2004).
H. Torii, N. Kuroda, M. Inoue, M. Hori, A. Mohri,
D. Barna, K. Komaki, and Y. Yamazaki: “Status
and Perspective of the ASACUSA antiproton trap
“MUSASHI””, 59th Ann. Meet. of Physical Soc. ofJapan, Fukuoka, Mar. (2004).
M. Terada, N. Nakamura, Y. Kanai, Y. Nakai, K.
Komaki, S. Ohtani, and Y. Yamazaki: “Surface
modiﬁcation by highly charged ions: STM/AFM observation of irradiated surface (2)”, 59th Ann. Meet.
of Physical Soc. of Japan, Fukuoka, Mar. (2004).
M. Fukuzumi, R. Taniguchi, N. Ishikawa, Y. Chimi,
T. Kambara, S. Komatsu, F. Ono, F. Hori, andA. Iwase: “Swift heavy ion induced magnetic phasetransition of Fe-Rh alloy”, 59th Ann. Meet. of Physical Soc. of Japan, Fukuoka, Mar. (2004).
Y. Fukuyama, Y. Moriwaki, and Y. Matsuo: “Temperature dependence of the formation and dissociation
cross section of Ba+∗ -He”, 59th Ann. Meet. of Physical Soc. of Japan, Fukuoka, Mar. (2004).
M. Hoshino, Y. Kanai, Y. Nakai, M. Kitajima, H.
Tanaka, and Y. Yamazaki: “The study of electron
capture processes for slow X4+ (X=C, N, O)-He collisions”, 59th Ann. Meet. of Physical Soc. of Japan,
Fukuoka, Mar. (2004).
Y. Iwai, Y. Kanai, Y. Nakai, T. Ikeda, H. Oyama, K.
Ando, H. Masuda, K. Nishio, H. Torii, K. Komaki,
and Y. Yamazaki: “X-ray measurement from N ionstransmitted through a microcapillary target”, 59th
Ann. Meet. of Physical Soc. of Japan, Fukuoka, Mar.
(2004).
T. Ikeda, Y. Nakai, Y. Kanai, Y. Iwai, H. Oyama,
H. Sato, Y. Takizawa, S. Shiki, C. Otani, H. M.
Shimizu, H. Masuda, K. Nishio, and Y. Yamazaki:“X-ray spectroscopy of highly-charged ions using
STJ detectors and X-ray lens”, 59th Ann. Meet. ofPhysical Soc. of Japan, Fukuoka, Mar. (2004).
Y. Kanai: “Spectroscopic study of ions transmitted from microcapillary tube”, China-Japan Symp.
on Atomic and Molecular Processes in Plasma(AMPP), (National Natural Science Foundation ofChina and JSPS), Lanzhou, China, Mar. (2004).

318

N. Oshima, M. Niigaki, A. Mohri, T. M. Kojima,
Y. Kanai, Y. Nakai, K. Komaki, and Y.
Yamazaki: “Cold highly charged ion production
with positron/electron cooling techniques”, 9th Int.
Symp. on Electron Beam Ion Sources and Traps andTheir Applications (EBIS/T 2004), Hachioji, Apr.
(2004).
Y. Fukuyama, Y. Moriwaki, and Y. Matsuo: “Laserinduced ﬂuorescence spectra of Ba+∗ -He exciplexes
in cold He gas of 3 – 30 K”, 59th Ohio State University Int. Symp. on Molecular Spectroscopy, Columbus, USA, June (2004).
T. Kambara: “Detection of acoustic signals induced byheavy-ion impact: Ion-beam seismology”, 21st Int.
Conf. on Atomic Collisions in Solids (ICACS 21),(Instituto Nazionale per la Fisica della Materia andDipartimento di Fisica dell Universita di Genova),
Genova, Italy, July (2004).
Y. Nakai, T. Ikeda, Y. Kanai, T. Kambara, N.
Fukunishi, K. Komaki, C. Kondo, T. Azuma, andY. Yamazaki: “Resonant coherent excitation of 2s
electron of Li-like Fe ions to the n=3 states”, 21stInt. Conf. on Atomic Collisions in Solids (ICACS21), (Instituto Nazionale per la Fisica della Materia
and Dipartimento di Fisica dell Universita di Genova), Genova, Italy, July (2004).
T. Kambara: “Heavy-ion irradiation of solids at
RIKEN accelerator facility”, 24th Werner Brandt
Workshop on Particle Penetration Phenomena andExcitations of Solids (WBW 24), Berlin, Germany,
July (2004).
N. Oshima, M. Niigaki, A. Mohri, T. M. Kojima, Y.
Kanai, Y. Nakai, K. Komaki, and Y. Yamazaki:“Application of a positron (electron) plasma forcooling of highly charged ions”, 41st Ann. Meet. on
Radioisotopes and Radiation in the Physical Scienceand Industries, (Japan Radioisotope Association),
Tokyo, July (2004).
M. Niigaki, N. Oshima, A. Mohri, T. M. Kojima, K.
Komaki, and Y. Yamazaki: “Current status and improvement plans of a positron accumulator”, 41stAnn. Meet. on Radioisotopes and Radiation in the
Physical Science and Industries, (Japan Radioisotope Association), Tokyo, July (2004).
Y. Kanai, A. Mohri, Y. Nakai, and Y. Yamazaki: “Development of a new method to prepare a polarized antihydrogen”, 29th Ann. Meet. of the Soc. for
Atomic Collision Research, Sendai, Aug. (2004).
Y. Iwai, Y. Kanai, Y. Nakai, T. Ikeda, M. Hoshino, H.
Oyama, K. Ando, H. Masuda, K. Nishio, H. Torii,
K. Komaki, and Y. Yamazaki: “X-ray measurementfrom N ions transmitted through a microcapillarytarget”, 29th Ann. Meet. of the Soc. for Atomic Collision Research, Sendai, Aug. (2004).
N. Oshima, M. Niigaki, A. Mohri, T. M. Kojima, Y.
Kanai, Y. Nakai, K. Komaki, and Y. Yamazaki:“Co-cooling scheme of highly charged ions with

positrons and electrons”, 12th Int. Conf. on the
Physics of Highly Charged Ions (HCI 2004), (VU
Research Institute of Theoretical Physics and Astronomy), Vilnius, Lithuania, Sept. (2004).
Y. Kanai, Y. Nakai, Y. Iwai, T. Ikeda, K. Nishio, H.
Masuda, and Y. Yamazaki: “Coincidence measurements of L X-ray and ﬁnal charge state of highly
charged Ar ions passing through a microcapillary”,
12th Int. Conf. on the Physics of Highly Charged
Ions (HCI 2004), (VU Research Institute of Theoretical Physics and Astronomy), Vilnius, Lithuania,
Sept. (2004).
Y. Iwai, Y. Kanai, Y. Nakai, T. Ikeda, M. Hoshino,
H. Oyama, K. Ando, H. Masuda, K. Nishio, H.
Torii, K. Komaki, and Y. Yamazaki: “X-rays emitted from N ions transmitted through a thin Ni microcapillary target”, 12th Int. Conf. on the Physics ofHighly Charged Ions (HCI 2004), (VU Research Institute of Theoretical Physics and Astronomy), Vilnius, Lithuania, Sept. (2004).
Y. Matsuda: “Development of slow muon beam line
at RIKEN-RAL muon facility (3)”, 2004 Autumn
Meet. of the Physical Soc. of Japan, Kochi and Aomori, Sept. (2004).
Y. Iwai, Y. Kanai, Y. Nakai, T. Ikeda, M. Hoshino,
H. Masuda, K. Nishio, and Y. Yamazaki: “L X-ray
measurement from Ar ions transmitted through microcapillaries 3”, 2004 Autumn Meet. of the PhysicalSoc. of Japan, Kochi and Aomori, Sept. (2004).
I. Shimamura, A. Igarashi, and J. F. McCann: “Relation between the time-delay matrix and the eigenphase sum: Application to resonance analysis theory”, 2004 Autumn Meet. of the Physical Soc. ofJapan, Kochi and Aomori, Sept. (2004).
A. Igarashi and I. Shimamura: “Resonances in thepositronium negative ion: Analysis in terms ofthe time-delay matrix”, 2004 Autumn Meet. of the
Physical Soc. of Japan, Kochi and Aomori, Sept.
(2004).
Y. Fukuyama, Y. Moriwaki, and Y. Matsuo: “Temperature dependence of the formation and dissociation
cross section of Ba+∗ -He (2)”, 2004 Autumn Meet.
of the Physical Soc. of Japan, Kochi and Aomori,Sept. (2004).
Y. Kanai, Y. Nakai, Y. Iwai, T. Ikeda, M. Hoshino, K.
Nishio, H. Masuda, and Y. Yamazaki: “X-ray measurements of highly charged Ar ions passing througha Ni microcapillary: coincidence of L X-ray and ﬁnal
charge state”, 8th Workshop on Fast Ion-Atom Collisions, (Institute of Nuclear Research of the Hungarian Academy of Sciences), Debrecen, Hungary, Sept.
(2004).
Y. Iwai, Y. Kanai, Y. Nakai, T. Ikeda, M. Hoshino, H.
Oyama, H. Masuda, K. Nishio, H. Torii, K. Komaki,
and Y. Yamazaki: “X-rays emitted from 2 keV/u N
ions passing through Ni microcapillaries”, 8th Workshop on Fast Ion-Atom Collisions, (Institution of

Nuclear Research of the Hungarian Academy of Science), Debrecen, Hungary, Sept. (2004).
E. Yagi, S. Koike, T. Sugawara, T. Shishido, T. Urai,and K. Ogiwara: “Site change of hydrogen in Nb
on alloying with high concentration of undersized
Mo atoms”, Int. Symp. on Metal-Hydrogen Systems:
Fundamentals & Applications (MH2004), Cracow,
Poland, Sept. (2004).
Y. Sakamaki, M. Hashimoto, Y. Fukai, K. Morita, J.
Yuhara, M. Kato, S. Koike, and E. Yagi: “Stressinduced states of hydrogen and deuterium in vanadium by channeling experiments”, Int. Symp. on
Metal-Hydrogen Systems: Fundamentals & Applications (MH2004), Cracow, Poland, Sept. (2004).
Y. Matsuda: “Development of slow muon beam line at
the RIKEN-RAL muon facility and new applicationsof mSR technique”, 9th Asia Paciﬁc Physics Conf.
(APPC 2004), (Association of Asia Paciﬁc PhysicalSocieties and others), Hanoi, Vietnum, Oct. (2004).

4.

Radiochemistry, radiation chemistry, and radiation biology

T. Shimada, M. Otani, H. Saito, and T. Abe: “Induction of mutations in sweet potato plants by heavyion beam irradiation”, 105th Ann. Congr. of the
Breeding Soc. of Japan, Tokyo, Mar. (2004).
K. Osawa, T. Abe, K. Maruta, S. Kadota, andH. Yamanishi: “Eﬀect of heavy-ion beam irradiation on the survival and growth of japanese pear”,
35th Ann. Meet. of Naganoken Engei Kenkyukai,
Minamiminowa-mura, Nagano Pref., Mar. (2004).
M. Miyasaka, T. Abe, K. Seki, and T. Usui: “Effects of heavy-ion beam irradiation on dry seedsof eustoma.”, 35th Ann. Meet. of Naganoken Engei Kenkyukai, Minamiminowa-mura, Nagano Pref.,Mar. (2004).
T. Abe: “Mutation breeding using heavy-ion beamirradiation”, 59th Ann. Meet. of Physical Soc. ofJapan, Fukuoka, Mar. (2004).
S. Motomura, H. Takeichi, S. Enomoto, M. Kibe, Y.
Gono, and Y. Yano: “Gamma-ray Compton imaging
by strip germanium telescope”, CNS-RIKEN Joint
Symp. on Frontier of Gamma-Ray Spectroscopy and
Its Application, Wako, Mar. (2004).
Y. Hase, S. Fujioka, S. Yoshida, K. Son, M. Umeda,
and A. Tanaka: “Analyses of frill1 mutant inducedby carbon-ion beam”, 1st Meet. of the Ion Beam
Breeding Soc., Takasaki, Apr. (2004).
K. Suzuki, Y. Takatsu, T. Gonai, Y. Miyazawa, H.
Saito, T. Abe, S. Yoshida, and M. Kasumi: “Induction of new ﬂower color mutant in spray-type
chrysanthemum”, 1st Meet. of the Ion Beam Breeding Soc., Takasaki, Apr. (2004).
M. Sugiyama, T. Terakawa, H. Saito, T. Abe, and S.
Yoshida: “Mutation induction by heavy-ion beams
in Pelargonium”, 1st Meet. of the Ion Beam Breed-319

ing Soc., Takasaki, Apr. (2004).
H. Saito, T. Abe, N. Fukunishi, H. Ryuto, K. Miyazaki,
T. Kusumi, K. Suzuki, and S. Yoshida: “Sterile verbena mutants induced by heavy-ion beam irradiation”, 1st Meet. of the Ion Beam Breeding Soc.,
Takasaki, Apr. (2004).
T. Morishita, H. Yamagichi, K. Debana, Y. Hase, N.
Shikazono, A. Tanaka, T. Abe, N. Fukunishi, Y.
Miyazawa, K. Sakamoto, and S. Yoshida: “Tartary backwheat mutants obtained by ion beams andgamma rays irradiation”, 1st Meet. of the Ion Beam
Breeding Soc., Takasaki, Apr. (2004).
M. Tomita, M. Aoki, and Y. Furusawa: “Molecularresponse of DNA double-strand break repair proteins”, Heisei15nendo HIMAC Kyodo Riyo Kenkyu
Seika Hapyokai, (National Institute of Radiological
Sciences), Chiba, Apr. (2004).
S. Motomura, H. Takeichi, M. Kibe, Y. Gono, S.
Enomoto, and Y. Yano: “Fourier analysis of backprojected images obtained by Compton camera composed of segmented Ge detectors”, 87th Scientiﬁc Meet. of Japanese Soc. of Medical Physics,
Yokoyama, Apr. (2004).
K. Igarashi, R. Hirunuma, H. Haba, S. Enomoto, andS. Kimura: “Inﬂuence of carnosine on the absorptionof iron and other trace elemetns in rats using multitracer technology”, 58th Ann. Meet. of Japanese
Soc. of Nurtrition and Food Science, Sendai, May(2004).
M. Tomita, A. Naruto, Y. Matsumoto, Y. Hosoi, N.
Suzuki, M. Izumi, and F. Yatagai: “Response of
DNA repair proteins to heavy ion induced DNA
damages”, 8th Int. Workshop on Radiation Damage
to DNA, Banﬀ, Canada, May (2004).
K. Igarashi, R. Hirunuma, S. Kimura, and S. Enomoto:“Eﬀect of polyphenol on the absorption of trace elements in rats”, 21st Symp. on Trace Nutrients Research, (Japan Trace Nutrients Research Society),
Kyoto, May (2004).
H. Haba, K. Morita, S. Enomoto, K. Morimoto, and D.
Kaji: “Development of a novel heavy element chemistry apparatus using the RIKEN gas-ﬁeld recoil separator as a pre-separator”, 8th Symp. on REIMEI
Research Resources, (JAERI), Tokai-mura, Ibaraki
Pref., June (2004).
Y. Kanayama, R. Amano, H. Haba, and S. Enomoto:“Brain uptake behavior of the 24 Na, 28 Mg, 43 K and
47
Ca by intranasal administration”, 15th Ann. Meet.
of the Japan Soc. for Biomedical Reserch on Trace
Elements, Tokyo, July (2004).
K. Igarashi, R. Hirunuma, S. Kimura, and S. Enomoto:“Eﬀect of carnosine on the iron absorption in rats”,
15th Ann. Meet. of the Japan Soc. for Biomedical
Reserch on Trace Elements, Tokyo, July (2004).
H. Eto, T. Abe, Y. Saito, S. Yoshida, and O. Saijo:“Floating farm—hydroponics of salt-tolerant rice
plants 1st report: Outline for facilities”, Ann. Meet.

320

of Architectural Institute of Japan 2004, Sapporo,Aug. (2004).
Y. Saito, T. Abe, H. Eto, S. Yoshida, and O. Saijo:“Floating farm—hydroponics of salt-tolerant rice
plants 2nd report: Two case studies”, Ann. Meet.
of Architectural Institute of Japan 2004, Sapporo,Aug. (2004).
H. Haba, K. Igarashi, D. Kaji, R. Hirunuma,
and S. Enomoto: “Development of a gas-jetcoupled multitarget system for multitracer production”, 6th Int. Conf. on Nuclear and Radiochemistry, (Forschungszentrum Julich), Aachen, Germany, Aug.–Sept. (2004).
A. Toyoshima, K. Tsukada, M. Asai, H. Haba, K.
Akiyama, I. Nishinaka, D. Saika, K. Matsuo, W.
Sato, H. Ishidu, M. Ito, J. Saito, S. Goto, H.
Kudo, H. Kikunaga, N. Kinoshita, C. Kato, A.
Yokoyama, K. Sueki, Y. Nagame, and A. Shinohara:“Elution behavior of rutherfordium (Rf) in anionexchange chromatography in a hydroﬂuoric acid system”, 6th Int. Conf. on Nuclear and Radiochemistry, (Forschungszentrum Julich), Aachen, Germany, Aug.–Sept. (2004).
K. Tsukada, H. Haba, M. Asai, A. Toyoshima, K.
Akiyama, I. Nishinaka, M. Hirata, K. Hashimoto,S. Ichikawa, Y. Nagame, K. Yasuda, Y. Miyamoto,Y. Tani, H. Hasegawa, W. Sato, A. Shinohara, S.
Goto, M. Ito, J. Saito, H. Ishidu, H. Kudo, Y.
Oura, H. Nakahara, K. Sueki, N. Kinoshita, H.
Kikunaga, and A. Yokoyama: “Sorption on anionexchange resin of dubnium and its homologues in
HF solution”, 6th Int. Conf. on Nuclear and Radiochemistry, (Forschungszentrum Julich), Aachen,
Germany, Aug.–Sept. (2004).
T. Abe and M. Arai: “Induction of mutations on carnation by ion beam radiation and comparison toother treatments”, 106th Ann. Congr. of Breeding
Soc. of Japan, Tsu, Sept. (2004).
H. Takeichi, S. Motomura, Y. Gono, Y. Yano, and S.
Enomoto: “Concurrent imaging of multiple radioactive tracers with a Compton camera”, 27th Ann.
Meet. of the Japan Neuroscience Soc./47th Ann.
Meet. of the Japan Soc. for Neurochemistry Joint
Meet. (Neuro2004), Osaka, Sept. (2004).
K. Igarashi, Y. Nakanishi, R. Hirunuma, S. Enomoto,and S. Kimura: “Nutritional study on eﬃcacy
of sodium iron ethylenediaminetetraacetic acid asa food fortiﬁcant”, 28th the Japan BioIron Soc.,
Tokyo, Sept. (2004).
T. Matsuyama, H. Ichida, K. Koike, H. Saito, T. Abe,T. Asami, T. Ebisuzaki, and S. Yoshida: “A DNA
polymorphism detection system by computer simulation using the Arabibidopsis genome sequences: A
virtual imaging restriction landmark genomic scanning”, 68th Ann. Meet. of the Botanical Soc. ofJapan, Fujisawa, Sept. (2004).
Y. Yamamoto, Y. Shimada, M. Kimura, H. Ryuto, N.

Fukunishi, T. Abe, and S. Yoshida: “Global classiﬁcation of transcriptional responses to light stress in
Arabidopsis thaliana”, 9th Int. Congr. of Endocytobiology and Symbiosis, Jena, Germany, Sept. (2004).
K. Osawa, I. Maruta, T. Abe, S. Tsunoda, and H. Yamanishi: “Eﬀects of heavy-ion beam irradiation on
in vitro shoot growht in japanese pear ‘Nansui’ ”,
Ann. Meet. 2004 of Japan Soc. for Horticultural Science, Shizuoka, Sept. (2004).
Y. Matsumoto, M. Tomita, A. Morita, Y. Hosoi, and
N. Suzuki: “XRCC4 as the genuine target of DNAPK in DNA double-strand break repair and themaintenance of genomic stability”, 63rd Ann. Meet.
of the Japanese Cancer Assoc., Fukuoka, Sept.–Oct.
(2004).
K. Tsukada, A. Toyoshima, H. Haba, M. Asai, K.
Akiyama, I. Nishinaka, Y. Nagame, D. Saika, K.
Matsuo, W. Sato, A. Shinohara, H. Ishizu, M.
Ito, J. Saito, S. Goto, H. Kudo, H. Kikunaga,
N. Kinoshita, C. Kato, A. Yokoyama, and K.
Sueki: “Anion-exchange chromatographic behaviorof Rutherfordium (Rf) in hydroﬂuoric acid”, 2004
Ann. Meet. on Japan Soc. of Nuclear and Radiochemical Sciences and 48th Symp. on Radiochemistry, Tokyo, Oct. (2004).
Y. Tani, H. Hasegawa, D. Saika, Y. Kitamoto, K.
Matsuo, W. Sato, N. Takahashi, T. Yoshimura, H.
Haba, and A. Shinohara: “Development of liquid
scintillation counting system for the on-line alpharay measurement of heavy elements”, 2004 Ann.
Meet. on Japan Soc. of Nuclear and Radiochemical
Sciences and 48th Symp. on Radiochemistry, Tokyo,
Oct. (2004).
D. Saika, Y. Kitamoto, K. Matsuo, Y. Tani, H.
Hasegawa, W. Sato, N. Takahashi, T. Yoshimura,
K. Takamiya, S. Shibata, H. Haba, S. Enomoto, and
A. Shinohara: “Development of online solvent extraction system for heavy actinide chemistry”, 2004
Ann. Meet. on Japan Soc. of Nuclear and Radiochemical Sciences and 48th Symp. on Radiochemistry, Tokyo, Oct. (2004).
K. Akiyama, H. Haba, K. Tsukada, M. Asai, K. Sueki,
A. Toyoshima, T. Yaita, and Y. Nagame: “EXAFS
study of the 4th and 5th group of elements in hydroﬂuoric acid”, 2004 Ann. Meet. on Japan Soc. of
Nuclear and Radiochemical Sciences and 48th Symp.
on Radiochemistry, Tokyo, Oct. (2004).
A. Toyoshima, K. Tsukada, M. Asai, H. Haba, K.
Akiyama, Y. Ishii, I. Nishinaka, T. Sato, M. Hirata,
Y. Nagame, W. Sato, K. Matsuo, Y. Tani, D.
Saika, Y. Kitamoto, H. Hasegawa, A. Shinohara, S.
Goto, M. Ito, J. Saito, H. Kudo, M. Sakama, A.
Yokoyama, K. Morishita, K. Sueki, H. Nakahara,
and M. Schaedel: “Formation of anionic ﬂuoride
complex of Rutherfordium (Rf): Anion-exchange
behavior in hydroﬂuoric acid/nitric acid mixed solution system”, 2004 Ann. Meet. on Japan Soc. of

Nuclear and Radiochemical Sciences and 48th Symp.
on Radiochemistry, Tokyo, Oct. (2004).
Y. Kanayama, R. Hirunuma, H. Haba, S. Enomoto,and R. Amano: “Olfactory transport of alkaline
metal ions by intranasal administration (2): Uptake behavior of Na+ and K+”, 2004 Ann. Meet.
on Japan Soc. of Nuclear and Radiochemical Sciences and 48th Symp. on Radiochemistry, Tokyo,
Oct. (2004).
H. Haba, K. Tsukada, K. Akiyama, M. Asai, A.
Toyoshima, Y. Ishii, S. Enomoto, and Y. Nagame:“Reversed-phase extraction chromatography of Zr
and Hf in the TBP/HCl system: Model experiments
for chemical characterization of element 104, rutherfordium”, 2004 Ann. Meet. on Japan Soc. of Nuclear
and Radiochemical Sciences and 48th Symp. on Radiochemistry, Tokyo, Oct. (2004).
H. Kikunaga, Y. Kasamatsu, K. Takamiya, T.
Mitsugashira, M. Hara, T. Ohtuki, H. Yuki, H.
Haba, A. Shinohara, S. Shibata, N. Kinoshita, A.
Yokoyama, and T. Nakanishi: “Search for the extremely low energy isomer of Th-229 by alphaspectrometry”, 2004 Ann. Meet. on Japan Soc. of
Nuclear and Radiochemical Sciences and 48th Symp.
on Radiochemistry, Tokyo, Oct. (2004).
Y. Kasamatsu, H. Kikunaga, K. Takamiya, T.
Mitsugashira, T. Nakanishi, T. Ohtuki, H. Yuki, H.
Haba, W. Sato, H. Yamana, Y. Ohkubo, M. Hara,
K. Ninomiya, S. Shibata, and A. Shinohara: “Visible and ultraviolet light measurement from the ultra low-lying isomer 229mTh”, 2004 Ann. Meet. on
Japan Soc. of Nuclear and Radiochemical Sciences
and 48th Symp. on Radiochemistry, Tokyo, Oct.
(2004).
H. Takeichi, S. Motomura, Y. Gono, H. Haba, R.
Hirunuma, K. Igarashi, Y. Yano, and S. Enomoto:“Concurrent tomography of multiple radioactive
tracers with a Compton camera”, 34th Ann. Meet.
of Soc. for Neuroscience (Neuroscience 2004), San
Diego, USA, Oct. (2004).
S. Motomura, H. Takeichi, R. Hirunuma, H. Haba,
K. Igarashi, S. Enomoto, Y. Gono, and Y. Yano:“Gamma-ray compton imaging of multitracer in biosamples by strip germanium telescope”, IEEE Rome
2004, Nuclear Science Symp., Rome, Italy, Oct.
(2004).
Y. Yamamoto, C. Bae, H. Saito, H. Ryuto, N.
Fukunishi, T. Abe, and S. Yoshida: “Heavy ion
beam mutagenesis of Arabidopsis thaliana andscreening for light stress mutants”, Joint Meet. of
14th Crucifer Genetics Workshop and 4th ISHS
Symp. on Brassicas (BRASSICA 2004), Daejeon,
Korea, Oct. (2004).
H. Takeichi, S. Motomura, Y. Gono, H. Haba, R.
Hirunuma, K. Igarashi, Y. Yano, and S. Enomoto:“Development of γ-ray emission imaging”, 17th Int.
Conf. on Cyclotrons and Their Applications (Cy-321

clotrons 2004), (RIKEN), Tokyo, Oct. (2004).
T. Abe, S. Yoshida, N. Fukunishi, H. Ryuto, andK. Suzuki: “The ion-beam breeding makes great
success in plant business”, 17th Int. Conf. on Cyclotrons and Their Applications (Cyclotrons 2004),(RIKEN), Tokyo, Oct. (2004).
L. H. Yin, Y. Suzuki, Y. Matsumoto, M. Tomita, Y.
Furusawa, A. Enomoto, A. Morita, M. Aoki, F.
Yatagai, T. Suzuki, Y. Hosoi, K. Ohtomo, and N.
Suzuki: “Molecular mechanisms of hyperthermic radiosensitization: Roles of DNA double-strand break
pathways”, 47th Ann. Meet. Japan Radiation Research Soc., Nagasaki, Nov. (2004).
M. Tomita, Y. Yano, F. Yatagai, N. Suzuki, Y. Hosoi,
and Y. Matsumoto: “Response of DSB repair proteins to accelerated iron ion induced DSBs”, 47th
Ann. Meet. Japan Radiation Research Soc., Nagasaki, Nov. (2004).
Y. Matsumoto, M. Tomita, L. H. Yin, A. Morita,
A. Enomoto, T. Suzuki, Y. Hosoi, K. Ohtomo,
and N. Suzuki: “The signiﬁcance of proteinphosphorylating function of DNA-PK in DNA
double-strand break repair: XRCC4 as the genuine
target”, 47th Ann. Meet. Japan Radiation Research
Soc., Nagasaki, Nov. (2004).
H. Takeichi, S. Motomura, and S. Enomoto: “A
multi-nuclide gamma-ray emission imaging system(GREI)”, 44th Ann. Meet. of Japanese Society of
Nuclear Medicine, Kyoto, Nov. (2004).
M. Tomita: “Response of DNA double-strand breakrepair proteins to low dose ionizing radiations”, PF
Seminar: Microbeam saibou shousha souti wo motiita teisenryo houshasen eikyou kenkyu ni kansuru
workshop, (Institute of Materials Structure Science,
KEK), Tsukuba, Dec. (2004).

5. Material Analysis
K. Maeda, k. Hasegawa, M. Maeda, K. Ogiwara, and
H. Hamanaka: “Time-resolved chemical state analysis by highly sensitive high-resolution PIXE”, 10th
Int. Conf. on Particle-induced X-ray Emission and
Its Analytical Applications, (Jozef Stefan Instituteand others), Portoroz, Slovenia, June (2004).
K. Mochiki, K. Okada, T. Toriyama, K. Kawasaki, K.
Sanetoshi, K. Maeda, and K. Hasegawa: “Development of an x-ray detecting system for WDX PIXE”,
21st PIXE Symp., (The Japan Society for Particle
Induced X-ray Emission (PIXE) Research), Tokyo,
Nov. (2004).
K. Maeda, K. Hasegawa, H. Hamanaka, K. Ogiwara,
M. Tsuji, and S. Murao: “In-air chemical state
analysis of Cr and Fe by PIXE using a positionsensitive crystal spectrometer”, 21st PIXE Symp.,(The Japan Society for Particle Induced X-ray Emis-

322

sion (PIXE) Research), Tokyo, Nov. (2004).
H. Hamanaka, K. Atsumi, F. Nagase, and K. Maeda:“PIXE analysis of ancient pottery (middle Jomon
period) excavated at Unasawa Shimonohara inTokyo (1)”, 21st PIXE Symp., (The Japan Society
for Particle Induced X-ray Emission (PIXE) Japan),Tokyo, Nov. (2004).

6. RIKEN-BNL Collaboration
Y. Goto: “Transversity and transverse-spin asymmetry measurements at PHENIX”, 5th European
Research Conf. on Electromagnetic Interactions
with Nucleons and Nuclei (EINN 2003), Parallel
Pre-Conf. Workshops B: Transversity, (Institute ofAccelerating Systems and Applications), Athens,
Greece, Oct. (2003).
M. Ohtani: “Soft mode near the critical end point in
the chiral quark model”, 59th Ann. Meet. of PhysicalSoc. of Japan, Fukuoka, Mar. (2004).
M. Hirai: “Polarized parton distributions and theiruncertainties”, RIKEN-TODAI Mini-Workshop on“Topics in Hadron Physics at RHIC”, Wako, Mar.
(2004).
T. Ikeda: “The eﬀect of memory on relaxation in φ4
theory”, RIKEN-TODAI Mini-Workshop on “Topics in Hadron Physics at RHIC”, Wako, Mar. (2004).
M. Ohtani: “Charge distribution of spin polarized
Skyrmion and the gauged Wess-Zumino term”, 2004
Autumn Meet. of the Physical Soc. of Japan, Kochi
and Aomori, Sept. (2004).
T. Tabaru, Y. Akiba, R. Averbeck, S. Butsyk, F.
Kajihara, M. Togawa, and Y. Tsuchimoto: “Mea√surement of single electrons in sN N = 62.4 GeV
Au-Au collisions at RHIC PHENIX”, 2004 Autumn
Meet. of the Physical Soc. of Japan, Kochi and Aomori, Sept. (2004).
A. Kiyomichi: “Radial ﬂow study via identiﬁed hadron
spectra in Au+Au collisions”, 2004 Autumn Meet.
of the Physical Soc. of Japan, Kochi and Aomori,Sept. (2004).
T. Ikeda and L. McLerran: “Understanding impact parameter in Balitsky-Kovchegov equation”, 2004 Autumn Meet. of the Physical Soc. of Japan, Kochi and
Aomori, Sept. (2004).
M. Ohtani: “Spin polarized Skyrmions in the UEM (1)gauged Wess-Zumino action”, 10th Int. Conf. on the
Structure of Baryons (Baryons 2004) , (L’Institut
de Physique Nucleaire d’Orsay), Palaiseau, France,
Oct. (2004).
M. Ohtani: “Spin polarized Skyrmions and the UEM (1)gauged Wess-Zumino term”, YITP Workshop on
Fundamental Problems and Applications of Quantum Field Theory, (Yukawa Institute for Theoretical
Physics), Kyoto, Dec. (2004).

IX. LIST OF SYMPOSIA(Jan.–Dec. 2004)
1) “Post Cluster’03” Cluster Project Workshop
7 Jan., Wako, Heavy Ion Nuclear Physics Lab., RIKEN
2) Studies on Condensed Matter Physics, Atomic Physics, Hyperfine Interactions and Biomedical Sciences
Using RIKEN Accelerators
19 Jan., Wako, Muon Science Lab., Atomic Physics Lab., Nuclear Chemistry Lab., and Cellular Physiology
Lab., RIKEN
3) Workshop on Cyclotron Mutagenesis (II)20 Jan., Wako, Plant Functions Lab., RIKEN
4) RHIC Spin Collaboration Meeting XXI
22 Jan., New York, USA, RBRC, RIKEN
5) Lattice QCD at Finite Temperature and Density
8–12 Feb., New York, USA, RBRC, RIKEN
6) Int. Workshop on Atomic Collisions of Slow/Trapped Highly-Charged Ions
19–21 Feb., Wako, Atomic Physics Lab., RIKEN
7) Workshop on Super Heavy Element Synthesis
26 Feb., Wako, Beam Technology Division, Cyclotron Center, RIKEN
8) RHIC Spin Collaboration Meeting XXII
27 Feb., New York, USA, RBRC, RIKEN
9) CNS-RIKEN Joint Symp. on Frontier of Gamma-ray Spectroscopy and Its Application
18–19 Mar., Wako, Heavy Ion Nuclear Physics Lab., RIKEN and CNS
10) RHIC Spin Collaboration Meeting XXIII
19 Mar., New York, USA, RBRC, RIKEN
11) RIKEN-TODAI Mini-Workshop on “Topics in Hadron Physics at RHIC”
23–24 Mar., Wako, Radiation Lab., RIKEN and University of Tokyo
12) Status Report of RIKEN Cluster Project
14–15 May, Wako, Heavy Ion Nuclear Physics Lab., RIKEN
13) New Discoveries at RHIC
14–15 May, New York, USA, RBRC, RIKEN
14) RHIC Spin Collaboration Meeting XXIV
21 May, New York, USA, RBRC, RIKEN
15) RHIC Spin Collaboration Meeting XXV
27 May, New York, USA, RBRC, RIKEN
16) The Present and Future of Muon Sciences at the RIKEN-RAL Muon Facility
27–28 May, Wako, Advanced Meson Science Lab., RIKEN
17) RHIC Spin Collaboration Meeting XXVI
1 June, New York, USA, RBRC, RIKEN

323

18) 1st Summer School on QCD Spin Physics
5–12 June, New York, USA, RBRC, RIKEN
19) RIBF-UEC/RIKEN Joint Workshop “Physics of Unstable Nuclei: These 10 years and From Now On”
15–17 June, Wako, Heavy Ion Nuclear Physics Lab., RIBF-UEC and RIKEN
20) Physics of Unstable Nuclei in This Decade and the Future
15–17 June, Wako, Heavy Ion Nuclear Physics Lab., RIKEN21) Int. Symp. on Exotic Nuclei (EXON 2004)
5–12 July, Peterhof, Russia, Heavy Ion Nuclear Physics Lab., JINR, RIKEN, GSI and GANIL
22) RHIC Spin Collaboration Meeting XXVII
22 July, New York, USA, RBRC, RIKEN
23) Int. Summer School on Subatomic Physics
26–30 Aug., Beijing, China, Heavy Ion Nuclear Physics Lab., RIKEN, PKE, IMP and others24) RHIC Spin Collaboration Meeting XXVIII
2 Sep., New York, USA, RBRC, RIKEN
25) RIBF Nuclear Physics Workshop “Mean Field and Collective Motion of Unstable Nuclei”
5–7 Sep., Wako, Heavy Ion Nuclear Physics Lab., RIKEN
26) Theory Summer Program on RHIC Physics
28 Sep., New York, USA, RBRC, RIKEN
27) Lectures on Hadron Physics
7–9 Oct., Wako, Radiation Lab., RIKEN, Tokyo Institute of Technology and University of Tokyo
28) RHIC Spin Collaboration Meeting XXIX
8–9 Oct., Torino, Italy, RBRC, University of Torino
29) 15th Inelastic Ion Surface Collision Workshop (IISC-15)
17–22 Oct., Shima, Atomic Physics Lab., JSAP
30) RIKEN Symp. on Development of Science with RI-beam below than 100 MeV/u
20 Oct., Wako, Applied Nuclear Physics Lab., RIKEN
31) High Performance Computing with BlueGene/L QCDOC Architectures
27–28 Oct., New York, USA, RBRC, RIKEN
32) 5th Italy-Japan Symp. on Recent Achievements and Perspectives in Nuclear Physics
3–7 Nov., Napoli, Italy, Heavy Ion Nuclear Physics Lab., RIKEN33) Workshop on the Physics Programme of the RBRC and UKQCD QCDOC Machines
12–13 Nov., New York, USA, RBRC, RIKEN34) Interim Report of RIKEN Cluster Project
15 Nov., Wako, Heavy Ion Nuclear Physics Lab., RIKEN35) RBRC Scientific Review Committee
16–17 Nov., New York, USA, RBRC, RIKEN36) RIKEN, Joint Workshop for Nuclear Reaction Theory and Experiment
26–27 Nov., Wako, Heavy Ion Nuclear Physics Lab., RIKEN

324

37) Japanese-Russian Workshop on Studies of Exotic Nuclei
3–4 Dec., Wako, Heavy Ion Nuclear Physics Lab., RIKEN
38) Physics at RHIC and Related Topics
6–7 Dec., Wako, Radiation Lab., RIKEN
39) RHIC-SPIN-J Physics Discussion
15 Dec., Kyoto , Radiation Lab., RIKEN40) Strongly Coupled Plasmas: Electromagnetic, Nuclear & Atomic
16–17 Dec., New York, USA, RBRC, RIKEN41) Japanese-German Workshop on Nuclear Structure and Astrophysics
16–18 Dec., Darmstadt, Germany, Heavy Ion Nuclear Physics Lab., RIKEN and GSI

325

X. LIST OF SEMINARS(Jan.–Dec. 2004)

RIKEN Nuclear-Physics Seminar
1) R. Seki, California State University (USA), 21Jan.
“Thermal properties of simple nucleon matter ona lattice”
2) W. G. Lynch, Michigan State University (USA),
3 Mar.
“Towards the equation of state of dense asymmetric matter”
3) W. Shen, Shanghai Institute of Applied Physics(China), 11 Mar.
“Radioactive ion beam physics and nuclear astrophysics in China”
4) Y. T. Oganessian, Flerov Laboratory of Nuclear
Reactions, JINR (Russia), 12 Mar.
“Heavy element research in Dubna”
5) K. Summerer, GSI (Germany), 6 Apr.
“High-energy Coulomb dissociation of 8 B”
6) H.-J. Schulze, Catania University (Italy), 14 June
“Hyperons in nuclear matter, neutron stars, andﬁnite nuclei”
7) S. Yoshida, Hosei University (Tokyo), 5 Aug.
“Neutron skin thickness and equation of state inneutron matter”
8) H. Nakada, Chiba University (Chiba), 12 Aug.
“New method, new interaction for mean-ﬁeld approximations and structure of unstable nuclei”
9) K. Iida, RBRC (USA), 21 Sep.
“Nuclear radius and the equation of state of nuclear matter”
10) H. Witala, Jagiellonian University (Poland), 6
Oct.
“Relativistic eﬀects in the elastic Nd scattering”
11) R. A. Gherghescu, National Institute for Nuclear
Physics and Engineering Bucharest (Romania), 1
Nov.
“Two center model for binary processes fusion
and ﬁssion”
12) W. Q. Shen, Shanghai Institute of Applied
Physics (China), 16 Nov.
“New machine for nuclear physics in China”

32613) G. Shirkov, JINR (Russia), 24 Nov.
“JINR and JINR basic facilities”
14) A. Ono, Tohoku University (Sendai), 14 Dec.
“Symmetry energy in multifragmentation”

Radiation Lab.
1) K. Ohnishi, University of Tokyo (Tokyo), 3 Feb.
“Mode coupling theory for the dynamic aspect of
the chiral phase transition”
2) G. Bunce, RBRC/BNL (USA), 24 Mar.
“The new muon g-2 result”
3) M. Nio, RIKEN (Wako), 24 Mar.
“Theory of muon g-2: Overview”
4) Y. En’yo, KEK (Tsukuba), 25 May“AMD study of pentaquark in a quark model”
5) S. Digal, University of Tokyo (Tokyo), 31 May“Induced critical behavior”
6) T. Inagaki, KEK (Tsukuba), 23 July
“Experiment on the rare decay KL → π 0 νν”
7) J. Noaki, RIKEN (Wako), 23 July
“Lattice QCD calculation of kaon matrix elements”
8) H. Lipkin, Weizmann Institute (Israel)/Argonne
National Laboratory (USA), 28 July
“What can we learn from QCD about pentaquarks and vice versa?”9) A. Hayashigaki, Kyoto University (Kyoto), 3
Aug.
“High-pT leading hadron suppression in heavyion collisions”
10) K. Fukushima, MIT (USA), 3 Aug.
“Heating (Gapless) color-ﬂavor locked quark matter”
11) T. Wettig, University of Regensburg (Germany),
9 Aug.
“Color-ﬂavor transformation and application tolattice QCD”
12) T. Yamazaki, RBRC/BNL (USA), 5 Oct.
“I = 2 S-wave pion scattering phase shift with
two ﬂavor full QCD”
13) T. Sugihara, RBRC/BNL (USA), 12 Oct.

“Matrix product variational formulation for lattice gauge theory”

Applied Nuclear Physics Lab.
1) P. F. Mantica, Michigan State University (USA),
18 Feb.
“Low-energy structure of exotic nuclei studied at
the NSCL using β-delayed γ ray and β-NMR
spectroscopies”
2) R. Neugart, University of Mainz (Germany), 24
Feb.
“Recent experiments at ISOLDE on the laser
spectroscopy and β-NMR spectroscopy with optically polarized beams”
3) E. Stachowska, Poznan University of Techbology(Poland), 24 Feb.
“Laser spectroscopic investigations on atoms with
open 3d and 4f shells: elements with high nuclear
spins”
4) F. Mareschal, Strasbourg University (France), 1
Mar.
“The beta decay of the heavy calcium isotopes”
5) H. H. Bertschat, Hahn-Meitner-Institut, Berlin(Germany), 23 Mar.
“Basic research on the atomic scale towards magnetic terabit memories: investigations with radioactive probe atoms”

Atomic Physics Lab.

Dec.
“Developing small area trends in surface analysis”

Heavy Ion Nuclear Physics Lab.
1) N. Otsuka, JCPRG (Sapporo)/JAERI (Tsukuba), 16 Jan.
“Introduction to nuclear data base”
2) A. Ono, Tohoku University (Sendai), 14 Dec.
“Nuclear equation of state and liquid-gas phasetransition”

Advanced Meson Science Lab.
1) H. Goka, IMR, Tohoku University (Sendai), 19Nov.
“A universal spin excitation in high-Tc superconductor”

Plant Functions Lab.
1) S. Y. Kang, KAERI (Korea), 24 Feb.
“New development of mutation breeding in Korea”
2) S. Ohno, Theoretical Radiation Research Laboratory (Yokohama), 21 May“An ion-track structure model to understandcross-sections for ion-induced DNA bond breaks”
3) A. Iwase, Research Institute for Advanced Scienceand Technology, Osaka Prefecture University (Osaka), 21 May“Structures and production mechanisms of GeVion induced tracks in inorganic materials”

1) A. V. Solov’yov, A. F. Ioﬀe Physical-TechnicalInstitute/Russian Academy of Sciences (Russia),
14 Apr.
“Fission, fusion and collision processes of atomic
clusters: ab initio and model approaches”

RIBF Project Group, Accelerator Sub-Group2) E. D. Donets, JINR (Russia), 23 Apr.
“Electron string phenomenon: physics and use”

2) P. Sigg, PSI (Switzerland), 5 Nov.
“Status of the PSI accelerators”

3) S. L. Chin, Laval University (Canada), 17 June
“Self-guided hot light pulse”

RIKEN BNL Research Center

4) A. Bai, National Institute of Advanced Industrial
Science and Technology (Tsukuba), 17 Sep.
“Atomic images of the defects on graphite byscanning probe microscopy”
5) K. M. Aggarwal, Queen’s University (UK), 15
Oct.
“Atomic data for plasma diagnostics”
6) R. Oiwa, “ULVAC PHI Incorporated (Tokyo), 3

1) L. Conradie, iThemba LABS (South Africa), 26
Oct.
“Status of the iThemba LABS accelerators”

1) Z. Sep, Hungarian Academy of Sciences (Hungary), 23 Jan.
“The T-mu phase diagram in the chiral quark
model from a large ﬂavor number expansion”
2) T. Sugihara, RBRC (USA), 5 Feb.
“Vector and chiral gauge theories on the lattice”
3) T. Kaneko, KEK (Japan), 11 Feb.
“Light hadron spectrum and quark masses inthree-ﬂavor dynamical QCD”

327

4) H. Meyer, Oxford University (UK), 12 Feb.
“Glueball Regge trajectories”
5) A. Gouvea, Northwestern University (USA), 18
Feb.
“What have we really learned from neutrino oscillation experiments?”
6) A. Gal, Hebrew University (Israel), 20 Feb.
“Indication of chiral symmetry restoration fromdeeply bound pionic atoms?”
7) W. Kinney, SUNY at Buﬀalo (USA), 25 Feb.
“Inﬂation after WMAP”

20) S. Gupta, Tata Institute of Advanced Research(India), 29 Apr.
“Transport and ﬂuctuations in ﬁnite-temperature
QCD”
21) D. Boyanovsky, University of Pittsburgh (USA),
30 Apr.
“Dynamical renormalization group approach torelaxation and transport”
22) T. Baltz, RBRC/BNL (USA), 6 May“Calculation of heavy-ion e+ e− pair production
to all orders in Zα”

8) S. Kretzer, RBRC (USA), 26 Feb.
“Strangeness asymmetry of the nucleon and other
QCD aspects of the NuTeV anomaly”

23) G. Zaharijas, New York University (USA), 12
May“Phenomenology of a stable or long-lived H dibaryon”

9) T. Falter, Universitaet Giessen (Germany), 27
Feb.
“High energy electroproduction oﬀ complex nuclei”

24) A. Gonzalez-Arroyo, Madrid/Rutgers (Spain), 26
May“Constructing vortices and instantons by expansion methods”

10) N. A. Perez, Cern (Switzerland), 10 Mar.
“Eﬀects of medium-induced gluon radiation on jet
shapes and heavy ﬂavors”

25) R. Venugopalan, BNL (USA), 27 May“k t factorization and beyond in gluon and quarkpair production in high energy hadronic collisions”

11) K. Tuchin , BNL (USA), 11 Mar.
“Cosmology inside hadrons”
12) S. Mrowczynski, Soltan Institute of Nuclear Studies (Poland), 12 Mar.
“Equilibration of the quark gluon plasma”
13) M. Piai, Yale University (USA), 17 Mar.
“A class of extended technicolor models”
14) G. Brown, SUNY at Stonybrook (USA), 19 Mar.
“What hath RHIC wrought?”
15) J. Giedt, University of Toronto (Canada), 7 Apr.
“Lattice (super) Yang-Mills and the dynamicallattice spacing”
16) Y. Dokshitzer, LPTHE (France), 15 Apr.
“Heavy quark physics”
17) C. Quigg, FNAL (USA), 21 Apr.
“Charmonium: The next wave”
18) A. Shoshi, Columbia University (USA), 22 Apr.
“Small-x physics beyond the Kovchegov equation”
19) K. Holland, UC San Diego (USA), 28 Apr.
“Triviality and the Higgs mass lower bound”

32826) H. Logan, University of Wisconsin (USA), 2 June
“The littlest higgs boson at a photon collider”
27) F. Petriello, Johns Hopkins University (USA), 9
June“Diﬀerential distributions in QCD at NNLO”
28) B. Kerbikov, ITEP (Russia), 10 June
“BCS-Bose crossover for quarks”
29) U. Florian, GSI (Germany), 22 June
“Strange particle production at SIS and GSI”
30) M. Tokarev, JINR, Dubna (Russia), 25 June
“New Veriﬁcation of Z-scaling at RHIC and theTevatron”
31) K. Iida, RBRC (USA), 15 July
“Nuclear radius and the equation of state of nuclear matter”
32) T. Krupovnickas, Florida State University (USA),
21 July“Collider reaches in SUSY”
33) T. Yamazaki, RBRC (USA), 22 July
“I = 2 π-π scattering phase shift with two ﬂavors
dynamical quark eﬀect”34) S. Munier, CPHT of the Ecole Polytechnique(France), 23 July
“New insights in high energy QCD from general tools of statistical physics (contracted from07/16/04)”
35) C. Marquet, SPhT-CEA, Saclay (France), 28 July
“Testing saturation with forward jets”
36) T. Doi, RBRC (USA), 29 July
“Pentaquark baryons from the QCD sum rule”
37) T. D. Lee, Columbia University/RBRC (USA), 5
Aug.
“New ways to solve the schrodinger equation”38) A. Muronga, Frankfurt University (Germany), 6
Aug.
“Nom-ideal ﬂuid dynamics for nuclear collisions”
39) D. Suprun, University of Chicago (USA), 11 Aug.
“Phenomenology of charmless hadronic B decays”40) G. Nayak, Stony Brook University (USA), 2 Sep.
“Gluon propagator in non-equilibrium and nonzero magnetic screening in QED and QCD at one
loop level”
41) D. Antonov, Humboldt University (Germany), 8
Sep.
“3D Georgi-Glashow model and conﬁning stringsat zero and ﬁnite temperatures”
42) R. Glauber, Harvard University (USA), 11 Sep.
Quantum optics and heavy-ion physics”
43) H. J. Pirner, Heidelberg University (Germany),
11 Sep.
“Low-x scattering as a critical phenomenon”
44) Y. Markov, Institut of System Dynamics andControl Theory Siberian Branch of Academy of
Sciences (Russia), 17 Sep.
“Nonlinear dynamics of soft boson collective excitations in hot QCD plasma: Bremsstrahlung andenergy losses”
45) E. Iancu, CEA Saclay (France), 8 Oct.
“Stochastic aspects of high energy QCD”

15 Oct.
“Deconﬁnement in matrix models and the GrossWitten point”
47) U. Heller, BNL (USA), 20 Oct.
“Light hadrons in 2 + 1 ﬂavor lattice QCD”
48) A. Stasto, BNL (USA), 21 Oct.
“Resummation at small x”49) S. Sasaki, RBRC (USA), 28 Oct.
“Pentaquarks: Status and perspectives for latticecalculations”
50) M. Lublinsky, University of Connecticut (USA),
29 Oct.
“High energy evolution beyond the BalitskiKovchegov equation”
51) D. Semikoz, UCLA (USA), 4 Nov.
“Ultra-high energy cosmic rays”
52) I. Low, Institute for Advanced Study (USA), 10
Nov.
“The little hierarchy problem”
53) S. Bass, Duke University (USA), 18 Nov.
“RHIC physics with the parton cascade model”
54) B. Gelman, Stony Brook University (USA), 19
Nov.
“What QGP at RHIC and cold dense atomic
clouds may have in common?”55) J. Pati, University of Maryland (USA), 1 Dec.
“Tying in CP and ﬂavor violations with fermion
masses and neutrino oscillations”
56) K. Petrov, BNL (USA), 2 Dec.
“Quarkonium correlators and spectral functions
at zero and ﬁnite temperature”57) G. Sterman, Stony Brook University (USA), 3
Dec.
“Single-particle production near the edge of phasespace”58) H. Warringa, Free University (The Netherlands),
9 Dec.
“Thermodynamics of QCD inspired theories”

46) A. Dumitru, University of Frankfurt (Germany),329

XI. LIST OF PERSONNEL
Supervisor for RIKEN Accelerator Research Facility
Supervisor
Hiromichi KAMITSUBO
Cyclotron Center
Director

Yasushige YANO

Accelerator-based Research Group
Director

Tohru MOTOBAYASHI

Experimental Equipment Sub-GroupSub-Group Leader
Deputy Sub-Group Leader

Masayuki KASE
Tadashi KAMBARA

LeaderGARIS
Atomic Collision ExperimentRadioisotope Production
SMART
Plant Irradiation Technology
Experimental Animal Irradiation
RIPS
Experimental Support
Computing and Networking Management
Experimental Research Sub-GroupSub-Group Leader (Non Nuclear Physics)
Deputy Sub-Group Leader (Nuclear Physics)

Kosuke MORITA
Tadashi KAMBARA
Shuichi ENOMOTO
Naruhiko SAKAMOTO
Tomoko ABE
Fumio YATAGAI
Toshiyuki KUBO
Tadashi KAMBARA
Takashi ICHIHARA

Yasunori YAMAZAKI
Koichiro ASAHI

LeaderNuclear Structure
Nuclear Reaction
Applied Nuclear Physics
Atomic Science
Animals and Cultured Cells Irradiation Research
Plant Mutation Research
Storage Ring
Analysis on Trace Elements
Detectors Development
Collaborative Research Sub-GroupSub-Group Leader
RIBF Project Group
Director
Process Management
LeaderConstruction Safety
Leader
Accelerator Sub-GroupSub-Group Leader

330

Tohru MOTOBAYASHI
Tohru MOTOBAYASHI
Koichiro ASAHI
Yasunori YAMAZAKI
Fumio HANAOKA
Shigeo YOSHIDA
Takeshi KATAYAMA
Yasushige YANO
Hideto EN’YO

Tohru MOTOBAYASHI

Yasushige YANO
Masayasu ISHIHARA
Nobuhisa FUKUNISHI
Hiromu OKAZOE
Atsushi YAMANAKA

Akira GOTO

Deputy Sub-Group Leader

Nobuhisa FUKUNISHI

LeaderProject Management
Ion-source Development

Nobuhisa FUKUNISHI
Takahide NAKAGAWA
Hiromitsu HABA
Osamu KAMIGAITO
Naohito INABE
Jun-ichi OHNISHI
Hiroki OKUNO
Kumio IKEGAMI

RRC-system Upgrade
Frc
Irc
SRC
Cryogenics

Equipment Development Sub-GroupSub-Group Leader
Deputy Sub-Group Leader

Tohru MOTOBAYASHI
Toshiyuki KUBO

LeaderCounter System Development
RIB Generator

Toshimi SUDA
Toshiyuki KUBO
Naoki FUKUDA
Koichiro ASAHI
Michiharu WADA
Masanori WAKASUGI
Tohru MOTOBAYASHI
Tohru MOTOBAYASHI
Tohru MOTOBAYASHI
Tohru MOTOBAYASHI
Takashi ICHIHARA
Yasushi WATANABE

RI Spin Probe Facility Development
SLOWRISCRITRI RingZero-degree Spectrometer
Daimajinp-RIPS
Networking and Data Processing Development
Data Acquisition Technique Development
Safety Sub-GroupSub-Group Leader

Yoshitomo UWAMINO

Cosmic Radiation Laboratory
Head
Kazuo MAKISHIMA
Members
Hiroshi KATO
Yukikatsu TERADA
Mitsuhiro KOHAMA∗∗

Toru TAMAGAWA
Tatehiro MIHARA

Special Postdoctoral Researcher

Visiting Members
Yasushi FUKAZAWA (Dept. Phys., Hiroshima Univ.)
Tateo GOKA (JAXA)
Soojing HONG (Dept. Phys., Saitama Univ.)
Madoka KAWAHARADA (Dept. Phys., Univ. Tokyo)
Yugo KIMOTO (JAXA)
Motohide KOKUBUN (Dept. Phys., Univ. Tokyo)
Hideki KOSHIISHI (JAXA)
Haruhisa MATSUMOTO (JAXA)
Takefumi MITANI (JAXA)
Hiromasa MIYASAKA (Cal. Inst. Technol., USA)Mio MURAKAMI (Dept. Phys., Univ. Tokyo)
Motoki NAKAJIMA (Coll. Sci. Technol., Nihon Univ.)
Kazuhiro NAKAZAWA (JAXA)
Masanori OHNO (Dept. Phys., Hiroshima Univ.)331

Yuu OKADA (Dept. Phys., Univ. Tokyo)
Tadayuki TAKAHASHI (JAXA)
Kazutaka YAMAOKA (Aoyama Gakuin Univ.)
Radiation Laboratory
Head
Hideto EN’YO
Members
Yasuyuki AKIBA
Yuji GOTO
Yoshie OTAKE
Kiyoshi TANIDA
Hiroaki OHNISHI∗1
Ryotaro MUTO∗1
Junji TOJO∗1
Kazumi HASUKO∗2
Masanori HIRAI∗2
Akio KIYOMICHI∗2
Munehisa OTANI∗2
Kazutaka SUDO∗2∗1∗2

Takashi ICHIHARA
Masayasu OKAMURA
Atsushi TAKETANI
Yasushi WATANABE
Tetsuya OHNISHI∗1
Hiroyuki TAKEDA∗1
Hisayuki TORII∗1
Johann HEUSER∗2
Hiroyuki KANO∗2
Junichi NOAKI∗2
Vladimir L. RYKOV∗2
Satoshi YOKKAICHI∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Masayuki ASAKAWA (Grad. Sch. Sci., Osaka Univ.)
Wolfgang BENTZ (Dept. Phys., Sch. Sci., Tokai Univ.)
Muriel Jane BURWARD-HOY (Dept. Phys., State Univ. New York, Stony Brook, USA)
Yoshihide FUCHI (KEK)
Hirotsugu FUJII (Grad. Sch. Arts Sci., Univ. Tokyo)
Tetsuo HATSUDA (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
Toshiyuki HATTORI (Tokyo Inst. Technol.)Kensuke HOMMA (Fac. Sci., Hiroshima Univ.)
Kenichi IMAI (Fac. Sci., Kyoto Univ.)
Katsuya ISHIGURO (Kanazawa Univ.)
Noriyoshi ISHII (Tokyo Inst. Technol.)Takeo KAWASAKI (Fac. Sci., Niigata Univ.)
Jirou KODAIRA (Fac. Sci., Hiroshima Univ.)
Yuji KOIKE (Fac. Sci., Niigata Univ.)
Shunzo KUMANO (Fac. Sci. Eng., Saga Univ.)
Teiji KUNIHIRO (YITP, Kyoto Univ.)
Youngil KWON (Dept. Phys., Seoul Natl. Univ., Korea)
Yajun MAO (Sch. Phys., Peking Univ., China)
Yasuo MIAKE (Inst. Phys., Univ. Tsukuba)
Shoichi MIDORIKAWA (Fac. Eng., Aomori Univ.)
Toshiyuki MORII (Fac. Human Dev., Kobe Univ.)
Osamu MORIMATSU (KEK)
Shoji NAGAMIYA (KEK)
Kenichi NAITO (Hokkaido Univ.)
Shogo NAKAMURA (Fac. Educ., Yokohama Natl. Univ.)
Akio OGAWA (Phys. Dept., BNL, USA)Jameson ROBERT (Institut Angewandth Physik, Goethe Universität Frankfurt)
Naohito SAITO (Fac. Sci., Kyoto Univ.)
Koichi SAITO (Fac. Sci. Technol., Tokyo Univ. Sci.)
Harutaka SAKAGUCHI (Fac. Sci., Kyoto Univ.)
Fuminori SAKUMA (Fac. Sci., Kyoto Univ.)
Digal SANATAN (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
Shinya SAWADA (KEK)
Michiko SEKIMOTO (KEK)332

Toshiaki SHIBATA (Tokyo Inst. Technol.)
Kenta SHIGAKI (Fac. Sci., Hiroshima Univ.)
Toru SUGITATE (Fac. Sci., Hiroshima Univ.)
Tsuneo SUZUKI (Kanazawa Univ.)
Manobu TANAKA (KEK)
Satoru TERASHIMA (Fac. Sci., Kyoto Univ.)
Thomas THROWE (Phys. Dept., BNL, USA)
Marcus WAGNER (Fac. Sci., Kyoto Univ.)
Yoshiaki YASUI (Tokyo Manage. Coll.)
Koichi YAZAKI (Tokyo Women’s Chr. Univ.)
Trainees
Kazuya AOKI (Fac. Sci., Kyoto Univ.)
Hisato EGUCHI (Fac. Sci., Niigata Univ.)
Kouhei FUJIWARA (Fac. Sci., Niigata Univ.)
Yoshinori FUKAO (Fac. Sci., Kyoto Univ.)
Takashi HACHIYA (Fac. Sci., Hiroshima Univ.)
Koichi HASHIMOTO (Kanazawa Univ.)
Yoshimasa HIDAKA (Fac. Sci., Univ. Tokyo)
Takuma HORAGUCHI (Tokyo Inst. Technol.)Yasuyoshi INOUE (Coll. Sci., Rikkyo Univ.)
Fukutarou KAJIHARA (CNS)
Nobuyuki KAMIHARA (Tokyo Inst. Technol.)
Hiroki KANO (Tokyo Inst. Technol.)
Masahiro KONNO (Inst. Phys., Univ. Tsukuba)
Kentarou MAWATARI (Fac. Hum. Dev., Kobe Univ.)
Takahiro NAGAI (Fac. Sci. Eng., Saga Univ.)
Junji NAGASHIMA (Fac. Sci., Niigata Univ.)
Tomoaki NAKAMURA (Fac. Sci., Hiroshima Univ.)
Yoshifumi NAKAMURA (Kanazawa Univ.)
Kenichi NAKANO (Tokyo Inst. Technol.)Megumi NARUKI (Fac. Sci., Kyoto Univ.)
Hiromi OKADA (Fac. Sci., Kyoto Univ.)
Shinsuke OOTA (CNS)
Toru SEKIDO (Kanazawa Univ.)
Maya SHIMOMURA (Inst. Phys., Univ. Tsukuba)
Kohei SHOJI (Fac. Sci., Kyoto Univ.)
Noriyuki SUGITA (Fac. Sci., Hiroshima Univ.)
Satoshi TAKAGI (Inst. Phys., Univ. Tsukuba)
Junpei TAKANO (Tokyo Inst. Technol.)
Akira TAKANO (Tokyo Inst. Technol.)
Manabu TOGAWA (Fac. Sci., Kyoto Univ.)
Yuji TUCHIMOTO (Fac. Sci., Hiroshima Univ.)
Takashi WATANABE (Tokyo Inst. Technol.)Kazuo YAMAMOTO (Tokyo Inst. Technol.)Hiroshi YOKOYA (Fac. Sci., Hiroshima Univ.)
Choong-Jae YOON (Fac. Sci., Kyoto Univ.)
Applied Nuclear Physics Laboratory
Head
Koichiro ASAHI
Members
Yoshio KOBAYASHI
Akihiro YOSHIMI∗

Hideki UENO
Tomohito HASEYAMA∗

Special Postdoctoral Researcher

Visiting Members
Minoru ADACHI

333

Hisazumi AKAI (Grad. Sch. Sci., Osaka Univ.)
Yasuaki EINAGA (Fac. Sci. Eng., Keio Univ.)
Koji HIGASHIYAMA (Grad. Sch. Sci., Univ. Tokyo)
Hideaki IZUMI (Grad. Sch. Sci. Eng., Osaka Univ.)
Norimichi KOJIMA (Grad. Sch. Arts Sci., Univ. Tokyo)
Kenya M. KUBO (Div. Natl. Sci., Int. Chr. Univ.)
Takuya KURAHASHI (Inst. Mol. Sci.)
Jiro MURATA (Fac. Sci., Rikkyo Univ.)
Masaki MURATA (Grad. Sch. Sci., Univ. Tokyo)
Kazuo MUTO (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)Yujiro NAGATA (Coll. Sci. Technol., Aoyama Gakuin Univ.)
Hiromichi NAKAHARA (Grad. Sch. Sci., Tokyo Metrop. Univ.)
Jin NAKAMURA (Dept. Appl. Phys. Chem., Univ. Electro-Commun.)
Saburo NASU (Grad. Sch. Eng. Sci., Osaka Univ.)
Hiroshi OGAWA (Natl. Inst. Adv. Ind. Sci. Technol.)
Takuya OKADA
Hiroyuki SAGAWA (Math. Sci., Univ. Aizu)
Kenji SAKAI (JAERI, CEPAF, Neutron Facility G.)
Wataru SATO (Grad. Sch. Sci., Osaka Univ.)
Kenzi SHIMADA (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)Tadashi SHIMODA (Grad. Sch. Sci. Eng., Osaka Univ.)
Satoshi TUTUI (Jpn. Syn. Rad. Res. Inst.)
Makoto UCHIDA (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)
Masahiko UTSURO (RCNP, Osaka Univ.)
Hiroshi WATANABE (Dept. Nucl. Phys., Australian Natl. Univ.)
Eiichi YAGI (Sch. Sci. Eng., Waseda Univ.)
Yasuhiro YAMADA (Fac. Sci., Tokyo Univ. Sci.)
Yutaka YOSHIDA (Fac. Sci. Technol., Shizuoka Inst. Sci. Technol.)Trainees
Takamasa ARAI (Fac. Sci., Tokyo Inst. Technol.)
Syoken EMORI (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)Shinya FUKAGAI (Sch. Sci. Eng., Waseda Univ.)
Shinichi HAGIWARA (Grad. Sch. Sci. Eng., Waseda Univ.)
Masaki HAYASHI (Sch. Sci. Eng., Waseda Univ.)
Tatsuya HAYASHI (Sch. Sci. Eng., Waseda Univ.)
Naota HIGAMI (Sch. Sci. Eng., Waseda Univ.)
Kazuhiro HIRABAYASHI (Sch. Sci. Eng., Waseda Univ.)
Yuichi HIRAISHI (Sch. Sci. Eng., Waseda Univ.)
Sayaka HORIE (Fac. Sci. Technol., Shizuoka Inst. Sci. Technol.)Takashi ITO (Fac. Sci., Tokyo Inst. Technol.)Shimon JINBO (Coll. Sci. Technol., Aoyama Gakuin Univ.)
Daisuke KAMEDA (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)
Go KATO (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)
Yoshihiro KAWAGUCHI (Div. Natl. Sci., Int. Chr. Univ.)
Go KIJIMA (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)Hiroshi MATSUBA (Grad. Sch. Sci. Eng., Waseda Univ.)
Jun MIYAZAKI (Grad. Sci., Tokyo Univ. Sci.)
Hisanori MIYOSHI (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)
Katsuhito MORI (Grad. Sch. Sci. Eng., Waseda Univ.)
Daisuke NAGAE (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)
Tetsuya NAKAGAWA (Fac. Sci., Tokyo Univ. Sci.)
Akio NAKAMOTO (Grad. Sch. Arts Sci., Univ. Tokyo)
Takanori NAKAYAMA (Fac. Sci. Technol., Shizuoka Inst. Sci. Technol.)
Yuki NEMOTO (Fac. Sci., Tokyo Univ. Sci.)
Hiroshi NONAKA (Fac. Sci., Tokyo Univ. Sci.)
Masashi OHKUBO (Grad. Sch. Arts Sci., Univ. Tokyo)
Yoshinori OKADA (Grad. Sch. Sci. Eng., Waseda Univ.)
Yuuki ONO (Grad. Sch. Arts Sci., Univ. Tokyo)
Sachiko OSHIMA (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)334

Kiwamu SAKUMA (Grad. Sch. Sci. Eng., Waseda Univ.)
Chika SUGI (Grad. Sch. Sci. Eng., Waseda Univ.)
Kunifumi SUZUKI (Fac. Sci. Technol., Shizuoka Inst. Sci. Technol.)
Kaori TAGUCHI (Div. Natl. Sci., Int. Chr. Univ.)
Makoto TAKEMURA (Fac. Sci., Tokyo Inst. Technol.)
Masato TSUKUI (Fac. Sci., Tokyo Inst. Technol.)Yoji TURUOKA (Div. Natl. Sci., Int. Chr. Univ.)
Motoyasu YOSHII (Grad. Sch. Sci. Eng., Waseda Univ.)
Atomic Physics Laboratory
Head
Yasunori YAMAZAKI
Members
Tadashi KAMBARA
Hitoshi OYAMA
Takao M. KOJIMA
Takane KOBAYASHI
Masaki OURA
Nobuhiro YAMANAKA∗1
Masamitsu HOSHINO∗1
Yoshihisa ISHIDA∗2
Naofumi KURODA∗2∗1∗2

Yasuyuki KANAI
Michiharu WADA
Yoichi NAKAI
Tokihiro IKEDA
Yoshio IWAI∗1
Makoto C. FUJIWARA∗1
Masahiro SHIBATA∗1
Nagayasu OSHIMA∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Kozo ANDO
Takeo ARUGA (Tokai Res. Estab., JAERI)
Yohko AWAYA (Coll. Art Design Gen. Ed., Musashino Art Univ.)
Toshiyuki AZUMA (Dept. Phys., Tokyo Metrop. Univ.)
Joachim BURGDÖRFER (Vienna Univ. Technol., Austria)
Yasuhiro CHIMI (Tokai Res. Estab., JAERI)
Jörg EICHLER (Hahn-Meiter-Inst. Berlin, Germany)
Atsushi HATAKEYAMA (Grad. Sch. Arts Sci., Univ. Tokyo)
Akira HITACHI (Kochi Med. Sch.)
Atsushi ICHIMURA (Inst. Space Astro. Sci.)
Akinori IGARASHI (Fac. Eng., Miyazaki Univ.)
Keishi ISHII (Fac. Sci. Eng., Ritsumeikan Univ.)
Norito ISHIKAWA (Tokai Res. Estab., JAERI)
Akio ITOH (Dept. Nucl. Eng., Kyoto Univ.)
Yoh ITOH (Fac. Sci., Josai Univ.)
Akihiro IWASE (Res. Inst. Adv. Sci. Technol., Osaka Pref. Univ.)
Kensuke KAGEYAMA (Fac. Eng., Saitama Univ.)
Ichiro KATAYAMA (KEK)
Kenji KIMURA (Fac. Eng., Kyoto Univ.)
Mineo KIMURA (Grad. Sch. Sci., Kyushu Univ.)
Masashi KITAJIMA (Fac. Sci. Technol., Sophia Univ.)
Tetsuo KOIZUMI (Dept. Phys., Rikkyo Univ.)
Ken-ichiro KOMAKI (Grad. Sch. Arts Sci., Univ. Tokyo)
Kenichi KOWARI (Dept. Appl. Phys. Chem., Univ. Electro-Commun.)
Kenro KUROKI (Natl. Res. Inst. Police Sci.)
Michio MATSUZAWA (Dept. Appl. Phys. Chem., Univ. Electro-Commun.)
Koichiro MITSUKE (Inst. Mol. Sci.)
Akihiro MOHRI
Kanetada NAGAMINE (Inst. Mater. Struc. Sci., KEK)
Nobuyuki NAKAMURA (Inst. Laser Sci., Univ. Electro-Commun.)Takashi NAKAMURA (KEK)
Tetsuya NAKAZAWA (Tokai Res. Estab., JAERI)

335

Megumi NIIGAKI (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
Tamio NISHIMURA (Dept. Chim., Univ. Roma, Italy)
Shunsuke OHTANI (Inst. Laser Sci., Univ. Electro-Commun.)
Kunihiro OKADA (Fac. Sci. Technol., Sophia Univ.)
Satoru OKAYASU (Tokai Res. Estab., JAERI)
Kazuhiko OKUNO (Dept. Phys., Tokyo Metrop. Univ.)
Fumihisa ONO (Fac. Sci., Okayama Univ.)
Lukas PICHL (Found. Comput. Sci. Lab., Univ. Aizu)
Frank B. ROSMEJ (Univ. Provence, France)
Syuiti SAKAGUTI (Fac. Eng., Yamaguchi Univ.)
Akio SAKAI (Vacuum Products Co.)
Reinhold SCHUCH (Phys. Dept., Stockholm Univ., Sweden)
Hans A. SCHUESSLER (Texas A & M Univ., USA)
Hiroyuki SHIMADA (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
Noriyuki SHIMAKURA (Fac. Sci., Niigata Univ.)
Isao SHIMAMURA
Hiroya SUNO (NIFS)
Aiko TAKAMINE (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
Michiya TAKEKAWA (Inst. Pure Appl. Phys.)
Hiroyuki TORII (Grad. Sch. Arts Sci., Univ. Tokyo)
Nobuyuki TOSHIMA (Inst. Appl. Phys., Univ. Tsukuba)
Hidetsugu TSUCHIDA (Dept. Nucl. Eng., Kyoto Univ.)
Kazuyuki UEDA (Toyota Technol. Inst.)
Kiyoshi UEDA (Res. Inst. Sci. Meas., Tohoku Univ.)
Victor VARENTSOV (V. G. Khlopin Radium Inst., Russia)
Tsutomu WATANABE
Akira YAGISHITA (KEK)
Yaming ZOU (Fudan Univ., China)
Trainees
Yoshinori ENOMOTO (Coll. Art Sci., Univ. Tokyo)
Masafumi FUKUZUMI (Grad. Sch. Eng., Osaka Pref. Univ.)
Matthew GARDNER (Univ. Birmingham, UK)
Masato INOUE (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
Hiroaki KANEMITSU (Dept. Phys., Okayama Univ.)
Seiji KOMATSU (Dept. Phys., Okayama Univ.)
Chikara KONDOU (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
Matthieu LEBOIS (Univ. Paris-Sud Orsay, France)
Vladimir LIOUBIMOV (Texas A&M Univ., USA)
Takuya MAJIMA (Grad. Sch. Eng., Kyoto Univ.)
Saburou MASUGI (Dept. Phys., Tokyo Metrop. Univ.)
Yuji MIYAMOTO (Grad. Sch. Sci. Eng., Sophia Univ.)
Tomoko MURANAKA (Dept. Phys., Tokyo Metrop. Univ.)
Yugo NAGATA (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
Yuji NAKANO (Dept. Phys., Tokyo Metrop. Univ.)
Tetsu SONODA (Grad. Sch. Sci., Tohoku Univ.)
Nozomi TANAKA (Dept. Phys., Sophia Univ.)
Masashi TERADA (Inst. Laser Sci., Univ. Electro-Commun.)
Kouhei YAMASHITA (Dept. Phys., Sophia Univ.)
Heavy Ion Nuclear Physics Laboratory
Head
Tohru MOTOBAYASHIMembers
Takashi ICHIHARA
Takashi KISHIDA
Yasushi WATANABE
Akihisa KOHAMA
Nori AOI

336

Toshimi SUDA
Alexei A. KORSHENINNIKOV
Yukari MATSUO
Shunji NISHIMURA
Yoshiyuki YANAGISAWA

Tomoko GOMI∗1
Masaaki KIMURA∗1
Toshiyuki SUMIKAMA∗1
Masaaki TAKASHINA∗1
Masayuki YAMAGAMI∗1
Evgueni NIKOLSKI∗2
Satoshi TAKEUCHI∗2
Toshimitsu YAMAZAKI∗2∗1∗2

Nobuaki IMAI∗1
Hiroshi MASUI∗1
Kanenobu TANAKA∗1
Kazunari YAMADA∗1
Yoshimitsu FUKUYAMA∗2
Parihawadana Aloy PERERA∗2
Meiko UESAKA-KUROKAWA∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Yasuhisa ABE (Yukawa Inst. Theor. Phys., Kyoto Univ.)
Yasuo AOKI (Fac. Sci., Univ. Tsukuba)
Shigeyoshi AOYAMA (Kitami Inst. Technol.)
Yoshihiro ARITOMO (JINR, Russia)
Daniel BAZIN (Natl. Supercond. Cycl. Lab., Michigan State Univ., USA)
Didier BEAUMEL (Paris-XI Univ., IPN-Orsay, France)
Francis A. BECK (CRN, Strasbourg, France)
Mottelson R BEN (NORDITA, Copenhagen, Denmark)Shawn BISHOP (JSPS)
Yorick BLUMENFELD (Paris-XI Univ., IPN-Orsay, France)
Peter von BRENTANO (Inst. fur Kern Phys., Univ. Koeln, Germany)
Rangacharyulu CHILAKAMARRI (Univ. Saskatchewan, Canada)
Zsolt DOMBRADI (Inst. Nucl. Res., Hung. Acad. Sci., Hungary)
Zoltan ELEKES (Inst. Nucl. Res., Hung. Acad. Sci., Hungary)
Yoshiko ENYO (KEK)Yoshitaka FUJITA (Fac. Sci., Osaka Univ.)
Mamoru FUJIWARA (RCNP, Osaka Univ.)
Mitsunori FUKUDA (Grad. Sch. Sci., Osaka Univ.)
Zsolt FÜLÖP (Inst. Nucl. Res., Hung. Acad. Sci., Hungary)
Zoltan GACSI (Inst. Nucl. Res., Hung. Acad. Sci., Hungary)
Janos GAL (Inst. Nucl. Res., Hung. Acad. Sci., Hungary)
Yu-Cheng GE (Peking Univ., China)
Adrian GELBERG (Inst. Kern Phys., Univ. Koeln, Germany)
Nobuyuki HASEBE (Sci. Eng. Res. Lab., Waseda Univ.)
Nguyen Thuc HIEN (Hanoi Univ., Vietnam)
Satoru HIRENZAKI (Fac. Sci., Nara Women’s Univ.)
Khiem LE HONG (Inst. Phys., Natl. Cen. Sci. Technol., Vietnam)
Shen HONG (Dept. Phys., Nankai Univ.)
TakatoshiI HORIBATA (Fac. Sci., Aomori Univ.)
Hisashi HORIUCHI (Fac. Sci., Kyoto Univ.)
Hui HUA (Michigan State Univ., USA)
Munetake ICHIMURA (Univ. Air)
Kazuo IEKI (Coll. Sci., Rikkyo Univ.)
Shigeru ISHIMOTO (KEK)
Naoyuki ITAGAKI (Fac. Sci., Univ. Tokyo)
Makoto ITO (Fac. Sci., Univ. Tsukuba)
Akira IWAMOTO (JAERI)
Naohisa IWASA (Fac. Sci., Tohoku Univ.)
Hironori IWASAKI (Grad. Sch. Sci., Univ. Tokyo)
Takuji IZUMIKAWA (Fac. Sci., Niigata Univ.)
Dang-Xing JIANG (Peking Univ., China)
Toshiki KAJINO (Natl. Astron. Obs.)
Nasser KALANTAR-NAYESTANAKI (Univ. Groningen, The Netherland)
Gabor KALINKA (Inst. Nucl. Res., Hung. Acad. Sci., Hungary)
Shoko KANNO (Coll. Sci., Rikkyo Univ.)
Kiyoshi KATO (Fac. Sci., Hokkaido Univ.)
Jun KIKUCHI (Sci. Eng. Res. Lab., Waseda Univ.)337

Kikuo KIMURA (Fac. Sci., Nagasaki Inst. Appl. Sci.)
Masanori KOBAYASHI (Sci. Eng. Res. Lab., Waseda Univ.)
Takeshi KOIKE (Nucl. Struct. Lab., State Univ. New York, Stony Brook, USA)
Tetsuro KOMATSUBARA (Univ. Tsukuba)
Evgueni KOUZMINE (Kurchatov Inst., Russia)
Attila KRASZNAHORKAY (Inst. Nucl. Res., Hung. Acad. Sci., Hungary)Kazuyoshi KURITA (Coll. Sci., Rikkyo Univ.)
Guan-Hua LIU (Inst. Modern Phys., China)
William LYNCH (Michigan State Univ., USA)
Kazushige MAEDA (Fac. Sci., Tohoku Univ.)
Kensaku MATSUTA (Fac. Sci., Osaka Univ.)
Kenichi MATSUYANAGI (Grad. Sch. Sci., Kyoto Univ.)
Jie MENG (Peking Univ., China)
Alberto MENGONI (ENEA, Italy)
Johannes G. MESSCHENDORP (Univ. Groningen, The Netherland)
Mototugu MIHARA (Fac. Sci., Osaka Univ.)
Toshiyuki MINEMURA (KEK)
Takashi MIYACHI (Fac. Sci. Eng., Waseda Univ.)
Yasuo MIYAKE (Fac. Sci., Univ. Tsukuba)
Hiroari MIYATAKE (KEK)
Takahiro MIZUSAKI (Fac. Sci., Univ. Tokyo)
Sadao MOMOTA (Kochi Univ. Technol.)Peter MOLLER (Los Alamos Natl. Lab., USA)
Hiroyuki MURAKAMI (Coll. Sci., Rikkyo Univ.)
Atsushi MUTA (Inst. Phys., Univ. Tsukuba)
Takayuki MYO (RCNP, Osaka Univ.)
Yasuki NAGAI (RCNP, Osaka Univ.)
Takashi NAKAMURA (Fac. Sci., Tokyo Inst. Technol.)Takashi NAKATSUKASA (Fac. Sci., Univ. Tsukuba)
Masahiro NOTANI (Argonne Natl. Lab., USA)
Atsuko ODAHARA (Nishinippon Inst. Technol.)Alexei A. OGLOBLIN (Kurchatov Inst., Russia)
Masahisa OHTA (Fac. Sci., Konan Univ.)
Hideaki OHTSU (Fac. Sci., Tohoku Univ.)
Takashi OHTSUBO (Fac. Sci., Niigata Univ.)
Takeo ONISHI (Grad. Sch. Sci., Univ. Tokyo)
Kazuhiro OYAMATSU (Aichi Shukutoku Univ.)
Chilakamarri RANGACHARYULU (Univ. Saskatchewan, Canada)
Zhou Zhang REN (Nanjing Univ., China)
Hiroyuki SAGAWA (Univ. Aizu)
Harutaka SAKAGUCHI (Fac. Sci., Kyoto Univ.)
Yoshinori SAKURAGI (Fac. Sci., Osaka City Univ.)
Kimikazu SASA (Univ. Tsukuba)
Hiroyuki SASADA (Keio Univ.)
Yoshiteru SATOU (Fac. Sci., Tokyo Inst. Technol.)
Ryoichi SEKI (Cal. State Univ., Northridge, USA)
Caiwan SHEN (Dept. Nucl. Phys., China Inst. Atom. Energy, China)
Yoshifumi SHIMIZU (Fac. Sci., Kyushu Univ.)
Cosimo SIGNORINI (INEN, Italy)
Dorottya SOHLER (Inst. Nucl. Res., Hung. Acad. Sci., Hungary)Takashi SUGIMOTO (Fac. Sci., Tokyo Inst. Technol.)
Kohsuke SUMIYOSHI (Numazu Coll. Technol.)Akihiro SUZUKI (Shinshu Univ.)
Masaru SUZUKI (Grad. Sch. Sci., Univ. Tokyo)
Shoji SUZUKI (KEK)Toshio SUZUKI (Fac. Eng., Fukui Univ.)
Yasuyuki SUZUKI (Fac. Sci., Niigata Univ.)
Naoki TAJIMA (Fac. Eng., Fukui Univ.)
Tadayuki TAKAHASHI (Inst. Space Astronaut. Sci.)
Yutaka TAKAHASHI (RCNP, Osaka Univ.)338

Masatoshi TAKANO (Sci. Eng. Res. Lab., Waseda Univ.)
Noboru TAKIGAWA (Fac. Sci., Tohoku Univ.)
Atsushi TAMII (RCNP, Osaka Univ.)
Kazuko TANABE (Otsuma Women’s Univ.)
Manyee TSANG (Michigan State Univ., USA)
Yutaka UTSUNO (Tokai Res. Estab., JAERI)
Takahiro WADA (Fac. Sci., Konan Univ.)
Herman WOLLNIK (Oak Ridge. Lab., USA)
Shuwei XU (Inst. Modern Phys., Chin. Acad. Sci., China)
Kazuhiro YABANA (Fac. Sci., Univ. Tsukuba)
Hirosuke YAGI (Fac. Sci., Univ. Tsukuba)
Kentarou YAKOU (Grad. Sch. Sci., Univ. Tokyo)
Takayuki YAMAGUCHI (Fac. Sci., Univ. Saitama)
Yanlin YE (Peking Univ., China)
Ken-ichirou YONEDA (Natl. Supercond. Cycl. Lab., Michigan State Univ., USA)
Naotaka YOSHINAGA (Fac. Sci., Saitama Univ.)
Shan-Gi ZHOU (Peking Univ., China)
Trainees
Akiko CHIBA (Fac. Sci., Univ. Tsukuba)
Masami CHIBA (Fac. Sci., Tohoku Univ.)
Jonathan Michael COOK (Michigan State Univ., USA)
Pham N. DINH (Michigan State Univ., USA)
Natsumi ENDO (Fac. Sci., Tohoku Univ.)
Hiroki FUJIWARA (Fac. Sci., Osaka Univ.)
Yasuro FUNAKI (Fac. Sci., Kyoto Univ.)
Takeshi FURUKAWA (Fac. Sci., Osaka Univ.)
Julien J. GIBELIN (Coll. Sci., Rikkyo Univ.)
Ryosuke HADATE (Coll. Sci., Rikkyo Univ.)
Yoshiko HASHIMOTO (Fac. Sci., Tokyo Inst. Technol.)Naho HOKOIWA (Fac. Sci., Kyushu Univ.)
Yuichi ICHIKAWA (Grad. Sch. Sci., Univ. Tokyo)
Kazuhiro ISHIKAWA (Fac. Sci., Tokyo Inst. Technol.)Ikuko KANAZAWA (Fac. Sci., Saitama Univ.)
Tomomi KATO (Fac. Sci., Niigata Univ.)
Shoko KAWAI (Coll. Sci., Rikkyo Univ.)
Yoshie KAWAMURA (Fac. Sci., Niigata Univ.)
Takayuki KINOSHITA (Coll. Sci., Rikkyo Univ.)
Mituhisa KITAYAMA (Fac. Sci., Tohoku Univ.)
Kei KOBAYASHI (Fac. Sci., Saitama Univ.)
Yousuke KONDOU (Fac. Sci., Tokyo Inst. Technol.)
Ryo KOYAMA (Fac. Sci., Niigata Univ.)
Hironori KUBOKI (Grad. Sch. Sci., Univ. Tokyo)
Shinichi KUMASHIRO (Fac. Sci., Osaka Univ.)
Chie KUROKAWA (Fac. Sci., Hokkaido Univ.)
Michitarou KUSAKA (Fac. Sci., Tohoku Univ.)
Yukie MAEDA (Grad. Sch. Sci., Univ. Tokyo)
Takashi MAEMURA (Fac. Sci., Saitama Univ.)
Tetsuya MASUDA (Coll. Sci., Rikkyo Univ.)
Yohei MATSUDA (Fac. Sci., Tohoku Univ.)
Nobuyuki MATSUI (Coll. Sci., Rikkyo Univ.)
Taizo MATSUMASA (Fac. Sci., Osaka Univ.)
Ryohei MATSUMIYA (Fac. Sci., Osaka Univ.)
Takafumi MATSUYAMA (Fac. Sci., Niigata Univ.)
Yuichi MATSUYAMA (Coll. Sci., Rikkyo Univ.)
Toshiya MIKI (Fac. Sci., Tohoku Univ.)
Kazutaka MIYAKAWA (Fac. Sci., Univ. Tsukuba)
Michal MOCKO (Michigan State Univ., USA)
Kensuke MORIMOTO (Coll. Sci., Rikkyo Univ.)
Konomi MURAKAMI (Fac. Sci., Saitama Univ.)339

Takashi NAGATOMO (Fac. Sci., Osaka Univ.)
Takumi NAKABAYASHI(Fac. Sci., Tokyo Inst. Technol.)Shinpei NAKAJIMA (Fac. Sci., Saitama Univ.)
Ryoko NAKAMURA (Coll. Sci., Rikkyo Univ.)
Taro NAKAO (Grad. Sch. Sci., Univ. Tokyo)
Hiroyuki NAKAYAMA (Grad. Sch. Sci., Univ. Tokyo)
Yuki NAOI (Fac. Sci., Tohoku Univ.)
Khai Thuan NGYEN (Hanoi Univ., Vietnam)
Haruki NISHINO (Grad. Sch. Sci., Univ. Tokyo)
Koremitsu OGATA (Fac. Sci., Saitama Univ.)
Masako OGURA (Fac. Sci., Osaka Univ.)
Masafumi OIZUMI (Grad. Sch. Sci., Univ. Tokyo)
Takashi OKUDA (Fac. Sci., Tohoku Univ.)
Toshifumi OKUMURA (Fac. Sci., Tokyo Inst. Technol.)
Hooi Jin ONG (Grad. Sch. Sci., Univ. Tokyo)
Kazutaka OZEKI (Fac. Sci., Tohoku Univ.)
Andrew ROGERS (Michigan State Univ., USA)
Hiroshi SAENMA (Grad. Sch. Sci., Univ. Tokyo)
Takaaki SAITO (Grad. Sch. Sci., Univ. Tokyo)
Shouta SAITO (Coll. Sci., Rikkyo Univ.)
Hazuki SAKAI (Coll. Sci., Rikkyo Univ.)
Takashi SAKO (Grad. Sch. Sci., Univ. Tokyo)
Tomoyuki SAKURADA (Coll. Sci., Rikkyo Univ.)
Makoto SASAKI (Fac. Sci., Osaka Univ.)
Masaki SASANO (Grad. Sch. Sci., Univ. Tokyo)
Junichi SATO (Coll. Sci., Rikkyo Univ.)
Kazunori SATO (Fac. Sci., Niigata Univ.)
Yoko SEKI (Fac. Sci., Tohoku Univ.)
Masatugu SEKIGUCHI (Fac. Sci., Tohoku Univ.)
Mayukko SHINOHARA (Fac. Sci., Tokyo Inst. Technol.)
Tokukazu SHINOHARA (Fac. Sci., Tohoku Univ.)
Daisuke SHINOJIMA (Fac. Sci., Niigata Univ.)
Wakako SHINOZAKI (Fac. Sci., Niigata Univ.)
Edward SMITH (Ohio Univ., USA)
Ryohei SUGO (Coll. Sci., Rikkyo Univ.)
Daisuke SUZUKI (Grad. Sch. Sci., Univ. Tokyo)
Hiroshi SUZUKI (Grad. Sch. Sci., Univ. Tokyo)
Ryusuke SUZUKI (Fac. Sci., Hokkaido Univ.)
Kensaku TAKAHASHI (Fac. Sci., Saitama Univ.)
Yoshiyuki TAKAHASHI (Grad. Sch. Sci., Univ. Tokyo)
Maya TAKECHI (Fac. Sci., Osaka Univ.)
Hideki TANAKA (Fac. Sci., Niigata Univ.)
Yasutaka TANIGUCHI (Fac. Sci., Kyoto Univ.)
Shinya TAZAWA (Fac. Sci., Tohoku Univ.)
Satoru TERASAWA (Fac. Sci., Kyoto Univ.)
Yasuhiro TOGANO (Coll. Sci., Rikkyo Univ.)
Kazuma TSURUSAKI (Grad. Sch. Sci., Univ. Tokyo)
Hirotaka UENO (Coll. Sci., Rikkyo Univ.)
Naori UMEZAWA (Coll. Sci., Rikkyo Univ.)
Kazuya URUSHIBARA (Coll. Sci., Rikkyo Univ.)
Toru UZIIE (Fac. Sci., Tohoku Univ.)
Yasuo WAKABAYASHI (Fac. Sci., Kyushu Univ.)
Mark WALLACE (Michigan State Univ., USA)
Kiwamu WATANABE (Fac. Sci., Tohoku Univ.)
Shigeo WATANABE (Fac. Sci., Niigata Univ.)
Takeshi WATANABE (Coll. Sci., Rikkyo Univ.)
Takuya YAGI (Grad. Sch. Sci., Univ. Tokyo)
Takashi YAKUSHIJI (Fac. Sci., Tohoku Univ.)
Koji YAMAGUCHI (Coll. Sci., Rikkyo Univ.)
Takuma YASUNO (Fac. Sci., Univ. Tsukuba)

340

Advanced Meson Science Laboratory
Head
Masahiko IWASAKIMembers
Teiichiro MATSUZAKI
Haruhiko OUTA
Yasuyuki MATSUDA
Takahisa KOIKE∗1
Pavel BAKULE∗2∗1∗2

Katsuhiko ISHIDA
Isao WATANABE
Kenta ITAHASHI
Shinji OKADA∗1
Seiko OHIRA∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Tadashi ADACHI (Grad. Sch. Eng., Tohoku Univ.)
Yoshitami AJIRO (Grad. Sch. Sci., Kyoto Univ.)
Yoshinori AKAISHI
Jun AKIMITSU (Coll. Sci. Eng., Aoyama Gakuin Univ.)
Juichiro ARAI (Fac. Sci., Tokyo Univ. Sci.)
Shingo ARAKI (Grad. Sch. Sci., Osaka Univ.)
Kunio AWAGA (Grad. Sch. Sci., Nagoya Univ.)
George A. BEER (Univ. Victoria, Canada)Hyoung Chan BHANG (Seoul Natl. Univ., Korea)
Ludmila N. BOGDANOVA (Inst. Theor. Exp. Phys., Russia)
Tara P. DAS (State Univ. New York, USA)
Mark P. FAIFMAN (Kurchatov Inst., Russia)
Yutaka FUJII (Fac. Eng., Fukui Univ.)
Masaki FUJITA (IMR, Tohoku Univ.)
Hideto FUKAZAWA (Grad. Sch. Sci. Eng., Chiba Univ.)
Makoto HAGIWARA (Fac. Eng. Design, Kyoto Inst. Technol.)
Emiko HIYAMA (Fac. Sci., Nara Women’s Univ.)
Susumu IKEDA (KEK)
Yutaka IKEDO (KEK)
Shigeru ISHIMOTO (KEK)
Tomoichi ISHIWATARI (Stefan Meyer Inst., Austria)
Atsuko ITO
Ryosuke KADONO (KEK)
Masayasu KAMIMURA
Mineo KATO (Tokai Res. Estab., JAERI)
Naritoshi KAWAMURA (KEK)
Yasushi KINO (Fac. Sci., Tohoku Univ.)
Yoh KOHORI (Fac. Sci., Chiba Univ.)
Youji KOIKE (Grad. Sch. Eng., Tohoku Univ.)
Yoshitaka KUNO (Grad. Sch. Sci., Osaka Univ.)
Syunsuke MAKIMURA (KEK)
Goro MARUTA (Grad. Sch. Sci., Hokkaido Univ.)
Yasuhiro MIYAKE (KEK)
Satoshi N. NAKAMURA (Grad. Sch. Sci., Tohoku Univ.)
Takashi NAKAMURA (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)
Takayoshi NAKAMURA (Res. Inst. Electron. Sci., Hokkaido Univ.)
Takehito NAKANO (Grad. Sch. Sci., Osaka Univ.)
Nobuhiko NISHIDA (Fac. Sci., Tokyo Inst. Technol.)Kusuo NISHIYAMA (KEK)
Yasuo NOZUE (Grad. Sch. Sci., Osaka Univ.)
Vassili V. PEREVOZCHIKOV (Russ. Fed. Nucl. Cen., Russia)
Leonid I. PONOMAREV (Kurchatov Inst., Russia)
Francis L. PRATT (RAL, UK)
Shinichi SAKAMOTO (Tokai Res. Estab., JAERI)
Ryoichi SEKI (California State Univ., USA)341

Koichiro SHIMOMURA (KEK)
Patrick STRASSER (KEK)
Hiroyuki SUGAI (Tokai Res. Estab., JAERI)
Keiji TAKEDA (Res. Inst. Electron. Sci., Hokkaido Univ.)
Hiroyuki TANAKA (Univ. Cal., Riverside, USA)
Eiko TORIKAI (Grad. Sch. Med. Eng. Sci., Univ. Yamanashi)
Akihisa TOYODA (KEK)
Kazuo UEDA (Inst. Solid State Phys., Univ. Tokyo)
Kazuyoshi YAMADA (IMR, Tohoku Univ.)
A. A. YUKHIMCHUK (Russ. Fed. Nucl. Cen., Russia)
Johann ZMESKAL (Stefan Meyer Inst., Austria)
Trainees
Soichiro ARIMURA (Grad. Sch. Sci., Osaka Univ.)
Ken GOTO (Grad. Sch. Sci., Osaka Univ.)
Kenichi HACHITANI (Grad. Sch. Sci., Chiba Univ.)
Aya HINO (Grad. Sch. Sci., Tohoku Univ.)
Hiroshi IMAO (Grad. Sch. Sci., Univ. Tokyo)
Junho JEONG (State Univ. New York, USA)
Mijung KIM (Seoul Natl. Univ., Korea)
Yoshihiro KUBOTA (Grad. Sch. Sci., Tohoku Univ.)
Sougo KUROIWA (Grad. Sch. Sci. Eng., Aoyama Gakuin Univ.)
Haruo MIYADERA (Grad. Sch. Sci., Univ. Tokyo)
RISDIANA (Grad. Sch. Eng., Tohoku Univ.)
Masaharu SATO (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)Ralph SCHEICHER (State Univ. New York, USA)
Yoko TOMITA (Coll. Sci. Eng., Aoyama Gakuin Univ.)
Maki YAMAZAWA (Grad. Sch. Sci. Eng., Aoyama Gakuin Univ.)
Heejoong YIM (Seoul Natl. Univ., Korea)
Magnetic Materials Laboratory
Head
Hidenori TAKAGIMembers
Masayuki HAGIWARA
Hiroki YAMAZAKI
Koshi TAKENAKA
Seiji NIITAKA∗1∗1∗2

Hiroko KATORI
Tetsuo HANAGURI
Katsuya IWAYA∗1Petra JONSSON∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Masaaki MATSUDA (JAERI-ASRC)
Hirokazu TSUNETSUGU (Yukawa Inst. Theor. Phys., Kyoto Univ.)
Kunimitsu UCHINOKURA
Trainees
Hideo NISHIKUBO (Dept. Supercond., Univ. Tokyo)
Seiichi SATO (Adv. Mater. Sci., Univ. Tokyo)
Tomohiro TAKAYAMA (Adv. Mater. Sci., Univ. Tokyo)
Cellular Physiology Laboratory
Head
Fumio HANAOKA
Members
Fumio YATAGAI

342

Visiting Members
Koichi ANDO (Natl. Inst. Radiol. Sci.)
Yoshiya FURUSAWA (Natl. Inst. Radiol. Sci.)
Yoshimasa HAMA (Sci. Eng. Inst., Waseda Univ.)
Hisao ITOH (Fac. Med., Chiba Univ.)
Tatsuaki KANAI (Natl. Inst. Radiol. Sci.)
Kiyomi KASAI (Natl. Inst. Radiol. Sci.)
Yasuhiko KOBAYASHI (JAERI)
Hiroshi WATANABE (JAERI)
Masami WATANABE (Fac. Pharm. Sci., Nagasaki Univ.)
Shoji YAMASHITA (Natl. Saitama Hosp.)
Plant Functions Laboratory
Head
Shigeo YOSHIDA
Members
Tomoko ABE
Hiroyuki SAITO∗1∗1∗2

Tomoki MATSUYAMA
Yoshiharu YAMAMOTO∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Chang-Hyu BAE (Sunchon Natl. Univ., Korea)
Koji FURUKAWA (Mukoyama Orchids Co., Ltd.)
Misako HAMATANI (Hiroshima City Agric. Forest. Promot. Cen.)
Yasuhide HARA (Kanagawa Inst. Agric. Sci.)
Masanori HATASHITA (Wakasa Wan Energy Res. Cen.)
Atsushi HIGASHITANI (Grad. Sch. Life Sci., Tohoku Univ.)
Akiko HOKURA (Fac. Sci., Tokyo Univ. Sci.)
Ichiro HONDA (Natl. Agric. Res. Cen., Min. Agric. Forest. Fish.)Mitsugu HORITA (Hokkaido Green-bio Inst.)
Yuji ITO (Inst. Rad. Breeding, Natl. Inst. Agric. Res.)
Hiroshi KAGAMI (Shizuoka Citrus Exp. Station)
Toshiaki KAMEYA (Grad. Sch. Life Sci., Tohoku Univ.)
Takeshi KANAYA (Suntory Flowers, Ltd.)Si-Yong KANG (Dep. Rad. Plant Breed. Genet., KAERI, Korea)
Takeo KITAURA (Kanagawa Inst. Agric. Sci.)
Tsutomu KUBOYAMA (Fac. Agric., Ibaraki Univ.)
Yutaka MIYAZAWA (Grad. Sch. Life Sci., Tohoku Univ.)
Kazumitsu MIYOSHI (Fac. Bioresour. Sci., Akita Pref. Univ.)
Toshikazu MORISHITA (Inst. Rad. Breeding, Natl. Inst. Agric. Res.)
Kenji Osawa (Nagano Agric. Res. Cen.)
Jin Heui PARK (Coll. Life Environ., Sci., Korea Univ., Korea)
Koichi SAKAMOTO (JAERI, Takasaki Rad. Chem. Res. Est.)
Tadashi SATO (Grad. Sch. Life Sci., Tohoku Univ.)
Takiko SHIMADA (Res. Inst. Agric. Resour., Ishikawa Agric. Coll.)
Masao SUGIYAMA (Hokko Chemical Ind. Co., Ltd.)
Kazunori SUZUKI (Plant Biotech. Inst. Ibaraki Agric. Cen.)
Kenichi SUZUKI (Suntory Flowers, Ltd.)Ken TOKUHARA (Dogashima Orchid Cen.)
Hisashi TSUJIMOTO (Fac. Agric., Tottori Univ.)
Takuji YOSHIDA (Takii Seed Co., Ltd.)
Masao WATANABE (Fac. Agric., Iwate Univ.)
Trainees
Hideki ASAUMI (Ehime Agric. Exp. Station)
Hiroyuki ICHIDA (Fac. Agric., Meiji Univ.)343

Tomojiro KOIDE (RIKEN Vitamin Co., Ltd.)
Hiroyuki NAGAYAMA (Fac. Sci., Tokyo Univ. Sci.)
Ryoko ONUMA (Fac. Sci., Tokyo Univ. Sci.)
Eikou OOYABU (Saga Agric., Exp. Station)
Minoru SAITO (Fukui Agric. Exp. Station)
Tsukasa SHIRAO (Kagoshima Biotech. Inst.)
Chisato SUZUKI (Fac. Agr., Meiji Univ.)
Hinako TAKEHISA (Grad. Sch. Life Sci., Tohoku Univ.)
Kei-ichiro UENO (Kagoshima Biotech. Inst.)
Tetsuya UMEKI (Miyazaki Agric. Exp. Station)
Kenji WATANABE (Fac. Agric., Meiji Univ.)
Cyclotron Center
Head
Yasushige YANOMembers
Satoru SUGIMOTO∗1
Hideki MADOKORO∗2∗1∗2

Nguyen Dinh DANG∗2
Yuko MOCHIZUKI∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Michio HONMA (Univ. Aizu)
Kiyomi IKEDA
Takashi INAMURA
Ken-ici KATO
Shoushichi MOTONAGA
Takaharu OTSUKA (Sch. Sci., Univ. Tokyo)
Mutsuko SASAKI
Noritaka SHIMIZU (Sch. Sci., Univ. Tokyo)
Takahiro TACHIBANA (Waseda High Sch., Waseda Univ.)
Kouji TAKAHASHI (Max Planck Inst., Germany)
Shuhei YAMAJI
Yumin ZHAO (Dept. Phys, Shanghai Jiao-Tong Univ., China)
Beam Dynamics Division
Head
Akira GOTO
Members
Takashi EMOTO
Jun-ichi OHNISHI
Tadashi KOSEKI
Osamu KAMIGAITO
Nobuhisa FUKUNISHI
Kimiko SEKIGUCHI∗1∗1∗2

Toshiyuki KUBO
Masanori WAKASUGIKouichi YOSHIDA
Atsushi YOSHIDA
Naruhiko SAKAMOTO
Kensuke KUSAKA∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Yoshiaki CHIBA
Mitsuhiro FUKUDA (Takasaki Res. Estab., JAERI)
Hironori KUBOKI (Dept. Phys., Sch. Sci., Univ. Tokyo)
Shinji MACHIDA (KEK)Toshinori MITSUMOTO (Sumitomo Heavy Ind., Ltd.)
Hiroari MIYATAKE (KEK)344

Hirofumi MIYAZAKI (Sumitomo Heavy Ind., Ltd.)
Yutaka MIZOI (Osaka Electro-Commun. Univ.)
Yoshiharu MORI (KEK)
Hiroyuki OKAMURA (Cycl. Radioisot. Cen., Tohoku Univ.)
Tsutomu SHINOZUKA (Cycl. Radioisot. Cen., Tohoku Univ.)
Eri TAKESHITA (Dept. Phys., Rikkyo Univ.)
Trainees
Takahiro AKIYAMA (Grad. Sch. Sci. Eng., Saitama Univ.)
Takashi HASEGAWA (Grad. Sch. Sci. Eng., Tohoku Univ.)
Keisuke ITOH (Grad. Sch. Sci. Eng., Saitama Univ.)
Youhei SHIMIZU (Grad. Sch. Sci. Eng., Osaka Univ.)
Kousuke SUGAHARA (Grad. Sch. Sci. Eng., Saitama Univ.)
Naoya SUGIMOTO (Grad. Sch. Sci. Eng., Tohoku Univ.)
Yuji TAMESHIGE (Grad. Sch. Sci. Eng., Osaka Univ.)
Beam Technology Division
Head
Masayuki KASE
Members
Kiyoshi OGIWARA
Makoto NAGASE
Kosuke MORITA
Kiminori USHIDA
Keiko KUMAGAI
Tamaki WATANABE
Masaki FUJIMAKI
Kohji MORIMOTO
Daiya KAJI∗1
Akiko MASUDA∗2
Tadashi FUJINAWA∗3
Shigeru YOKOUCHI∗3
Jiro FUJITA∗4

Tadashi KAGEYAMA
Shigeo KOHARA
Takahide NAKAGAWA
Eiji IKEZAWA
Naohito INABE
Toshiya TANABE
Sachiko ITO
Yoshihide HIGURASHI∗1
Masanori KIDERA∗2
Hiromichi RYUTOU∗2
Misaki KOBAYASHI-KOMIYAMA∗3
Akira YONEDA∗3
Kenichi YAMAGUCHI∗4∗1

Special Postdoctoral Researcher
Contract Researcher∗3
Contract Technical Assistant∗4
Temporary Employee∗2

Visiting Members
Hiroaki ASAI (JAXA)
Keisuke ASAI (Fac. Eng., Tohoku Univ.)
Toshiya CHIBA
Shin-ichi GOTO (Niigata Univ.)
Naoyuki HASEBE (Adv. Res. Inst. Sci. Eng., Waseda Univ.)
Hiroo HASEBE (Katagiri Eng. Co., Ltd.)
Masatake HEMMI
Yoshiya IIDE (JAXA)
Naomi IKEDA (JAXA)
Masayuki ITO (Adv. Res. Inst. Sci. Eng., Waseda Univ.)
Toshiji ITOH
Chihiro KAMEZAWA (JAXA)
Kenji KATORI
Kazuie KIMURA
Masanori KOSHIMIZU (Fac. Eng., Tohoku Univ.)
Hiroyuki KOURA (JAERI, Tokai)
Satoshi KUBOYAMA (JAXA)
Hisaaki KUDO (Fac. Sci., Niigata Univ.)
Sumio MATSUDA (JAXA)

345

Takehiro MATSUSE (Fac. Textile Sci. Technol., Shinshu Univ.)
Hideo MIKAMI (SHI Accel. Serv., Ltd.)
Takashi MIYACHI (Adv. Res. Inst. Sci. Eng., Waseda Univ.)
Yoshitoshi MIYAZAWA
Tetsuya MURAKAMI (Grad. Sch. Sci., Kyoto Univ.)
Toru NOMURA
Ryusuke NOZAKI (Dept. Phys., Hokkaido Univ.)
Junichi ODAGIRI (KEK)
Hideharu OHIRA (JAXA)
Koji OISHI (Shimizu Constr. Co., Ltd.)
Katsumi OKA (JAXA)
Osamu OKUDAIRA (Adv. Res. Inst. Sci. Eng., Waseda Univ.)
Hiromitsu OOTOMO (JAXA)
Yuichiro SASAKI (Matsushita Electr. Ind. Co., Ltd.)
Hiroki SATO (JAXA)
Osamu SHIMADA (JAXA)
Hiroyuki SHINDO (JAXA)
Keisuke SUEKI (RI Cen., Univ. Tsukuba)
Fuyuki TOKANAI (Dept. Phys., Yamagata Univ.)
Ryoichi WADA (Texas A & M Univ., USA)
Masakazu WASHIO (Adv. Res. Inst. Sci. Eng., Waseda Univ.)
Ichiro YOKOYAMA
Kenji YOSHINO (Fac. Eng., Miyazaki Univ.)
Trainees
Kentaro ASAI (Grad. Sch. Sci. Eng., Waseda Univ.)
Takehiko KURIBAYASHI (Grad. Sch. Sci. Eng., Waseda Univ.)
Naoyuki YAMASHITA (Grad. Sch. Sci. Eng., Waseda Univ.)
Liquid Helium Service Division
Head
Yasushige YANOMembers
Kumio IKEGAMI
Hiroki OKUNO
Toshiharu TOMINAKA∗1∗1∗2

Masato NAKAMURA
Masao OTAKE
Tatsuhiko YOSHIDA∗2

Contract Researcher
Temporary Employee

Radioisotope Technology Division (∼2004. 5. 31)
Head
Fumio YATAGAI (∼2004. 3. 31)
Yasushige YANO (2004. 4. 1∼2004. 5. 31)
Visiting Members
Masamitsu HONMA (Natl. Inst. Health Sci.)
Atsushi ITO (Sch. Eng., Tokai Univ.)
Osamu KAWAGUCHI (Sch. Med., Keio Univ.)
Tetsuya KAWATA (Fac. Med., Chiba Univ.)
Hideaki MAEKAWA (Natl. Inst. Infect. Dis.)
Hiroshi MAEZAWA (Fac. Med. Technol., Univ. Tokushima)
Takehiko NOHMI (Natl. Inst. Health Sci.)
Takeo OHNISHI (Fac. Biol., Nara Med. Univ.)
Toshihiro OHTA (Fac. Life Sci., Tokyo Univ. Pharm. Life Sci.)
Akihisa TAKAHASHI (Fac. Biol., Nara Med. Univ.)
Kaoru TAKAKURA (Div. Natl. Sci., Int. Chr. Univ.)346

Trainees
Tsutomu MATSUO (Fac. Sci. Eng., Waseda Univ.)
Aiko NARUTO (Fac. Life Sci., Tokyo Univ. Pharm. Life Sci.)
Toshitaka OKA (Fac. Sci. Eng., Waseda Univ.)
Momoko TAKAHASHI (Div. Natl. Sci., Int. Chr. Univ.)
Application Development Division (2004. 6. 1∼)
Head
Yasushige YANOMembers
Kazuya TAKAHASHI
Hiroshige TAKEICHI
Teruyo TSUKADA
Kaori IGARASHI∗2
Masanori TOMITA∗2∗1∗2

Shuichi ENOMOTO
Masako IZUMIShinji MOTOMURA∗1
Akihiro NAKAYAMA∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Ryohei AMANO (Fac. Med., Kanazawa Univ.)
Sachiko AMARI (Washington Univ., USA)
Wenjun DING (Colorado State Univ., USA)
Kazutoyo ENDO (Showa Pharm. Univ., USA)
Tatsunori FUKUMAKI (Japan NUS Co., Ltd.)
Mika FUKUOKA (Tokyo Univ. Fish.)Yasuyuki GONO
Hiroshi HIDAKA (Fac. Sci., Hiroshima Univ.)
Seiichiro HIMENO (Fac. Pharm. Sci., Tokushima Bunri Univ.)
Eiko HIRANO (Japan NUS Co., Ltd.)
Takako IKEDA (Showa Women’s Univ.)
Hiroko INAGE (Int. Life Sci. Inst.)
Nobuyoshi ISHII (Natl. Inst. Radiol. Sci.)
Toshiaki ISHII (Natl. Inst. Radiol. Sci.)
Hiroyuki KAGI (Grad. Sch. Sci., Univ. Tokyo)
Yousuke KANAYAMA (Grad. Sch. Med. Sci., Kanazawa Univ.)
Kenji KAWABE (Kyoto Pharm. Univ.)
Shuichi KIMURA
Masuo KONDOH (Showa Pharm. Univ.)
Kuniko MAEDA
Ken-ichiro MATSUMOTO (Natl. Inst. Health, USA)
Yoshitaka MINAI (Cen. Art. Sci., Musashi Univ.)
Takeshi MINAMI (Dept. Life Sci., Sch. Sci. Eng., Kinki Univ.)
Tomohiro NABEKURA (Fac. Pharm. Sci., Niigata Univ. Pharm. Appl. Life Sci.)
Yuichiro NAGAME (JAERI)
Tomoko NAKANISHI (Grad. Sch. Agric. Life Sci., Univ. Tokyo)
Yukiko NAKANISHI (Int. Life Sci. Inst.)
Van Chuyen NGUYEN (Jpn. Women’s Univ.)
Yasumitsu OGURA (Grad. Sch. Pharm. Sci., Chiba Univ.)
Jun SAITO (Iwatsu Test Instrum. Corp.)
Tomofumi SAKURAGI (Natl. Inst. Radiol. Sci.)
Hiromu SAKURAI (Kyoto Pharm. Univ.)
Sadao SHIBATA (Nucl. Safety Technol. Cen.)
Hiroshi SHIMIZU (Fac. Sci., Hiroshima Univ.)
Atsushi SHINOHARA (Dept. Chem., Grad. Sch. Sci., Osaka Univ.)
Hiroyuki SUZUKI (RI Res. Cen., Chiba Univ.)
Kazuo T. SUZUKI (Grad. Sch. Pharm. Sci., Chiba Univ.)
Mikiko SUZUKI (Showa Women’s Univ.)347

Toshihiro SUZUKI (Meiji Pharm. Univ.)
Keiko TAGAMI (Natl. Inst. Radiol. Sci.)
Masaaki TAKAHASHI (Grad. Sch. Agric. Biol. Sci., Osaka Pref. Univ.)
Miho TAKAHASHI (Tokyo Univ. Fish.)
Yoshio TAKAHASHI (Grad. Sch. Sci., Hiroshima Univ.)
Atsushi TAKEDA (Sch. Pharm. Sci., Univ. Shizuoka)
Haruna TAMANO (Sch. Pharm. Sci., Univ. Shizuoka)
Shinzo TANABE (Meiji Pharm. Univ.)
Tadayasu TOGAWA (Meiji Pharm. Univ.)
Takehiro TOMITANI (Natl. Inst. Radiol. Sci.)
Shigeo UCHIDA (Natl. Inst. Radiol. Sci.)
Kohshin WASHIYAMA (Fac. Med., Kanazawa Univ.)
Mineo YAMASAKI (Nara Med. Univ.)
Makoto YANAGA (Fac. Sci., Shizuoka Univ.)
Hiroyuki YASUI (Kyoto Pharm. Univ.)
Akihiko YOKOYAMA (Fac. Sci., Kanazawa Univ.)
Shigekazu YONEDA (Natl. Sci. Museum)Shozo YOSHIDA (Nara Med. Univ.)
Takashi YOSHIMURA (Grad. Sch. Sci., Osaka Univ.)
Trainees
Yusuke ADACHI (Grad. Sch. Pharm. Sci., Kyoto Pharm. Univ.)
Tomoko ANDO (Sch. Hum. Life Sci., Showa Woman’s Univ.)
Masako HASAMA (Grad. Sch. Hum. Life Sci., Showa Woman’s Univ.)
Hiroko HASEGAWA (Grad. Sch. Sci., Osaka Univ.)
Ryoichi HIRAYAMA (Grad. Sch. Sci. Technol., Chiba Univ.)
Kenichi ISHIBASHI (Meiji Pharm. Univ.)
Yoshiharu ISOBE (Dept. Radiol. Sci., Ibaraki Pref. Univ.)
Hanako KAJIYA (Grad. Sch. Hum. Life Sci., Showa Woman’s Univ.)
Yoshitaka KASAMATSU (Grad. Sch. Sci., Osaka Univ.)
Nobuyuki KINUGAWA (Grad. Sch. Sci. Technol., Shizuoka Univ.)
Yusuke KITAMOTO (Grad. Sch. Sci., Osaka Univ.)
Keiko MANABE (Grad. Div. Hum., Ochanomizu Univ.)
Keiji MATSUO (Grad. Sch. Sci., Osaka Univ.)
Akiko MIDORIKAWA (Grad. Div. Hum., Ochanomizu Univ.)
Ryuji MINAYOSHI (Grad. Sch. Sci. Technol., Shizuoka Univ.)
Takanori OGI (Grad. Sch. Sci. Technol., Shizuoka Univ.)
Shigeki OHATA (Meiji Pharm. Univ.)
Mizue OZAKI (Grad. Sch. Pharm. Sci., Meiji Pharm. Univ.)
Daisuke SAIKA (Grad. Sch. Sci., Osaka Univ.)
Naoko SATOU (Meiji Pharm. Univ.)
Tomomasa TAKABE (Sch. Sci., Osaka Univ.)
Yuuki TANI (Grad. Sch. Sci., Osaka Univ.)
Yuki TASHIRO (Sch. Sci., Osaka Univ.)
Makoto YATSUKAWA (Grad. Sch. Sci., Osaka Univ.)
Atsushi YUMOTO (Grad. Sch. Pharm. Sci., Meiji Pharm. Univ.)
Safety & Security Oﬃce
Head
Yasushige YANOMembers
Shin FUJITA
Hisao SAKAMOTO∗2
Hiroki MUKAI∗4∗1

Contract Researcher
Contract Technical Scientist∗3
Temporary Employee∗4
Visitng Contract Oﬃcer∗2

348

Rieko HIRUNUMA∗1
Tsutomu YAMAKI∗3

ADVANCED DEVELOPMENT AND SUPPORTING CENTER
Beam Application Team
Head
Takashi MEGURO
Members
Tomohiro KOBAYASHI
Kowashi WATANABE

Aiko NAKAORESEARCH UNIT
Image Information Research Unit
Head
Hirohiko M. SHIMIZU
Members
Hiromi SATO
Kazuaki IKEDA∗1
Tomohiro ADACHI∗2
Katsuya HIROTA∗2
Kenji MISHIMA∗2
Shigetomo SHIKI∗2∗1∗2

Seiichiro ARIYOSHI∗1
Masashi OHNO∗1Mario E. BERTAINA∗2
Masahiko KURAKADO∗2
Takahiro MORISHIMA∗2
Takenao SHINOHARA∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Tadashi KIFUNE (Fac. Eng., Shinshu Univ.)
Hiroaki MYOREN (Fac. Eng., Saitama Univ.)
Takayuki OKU (JAERI)
Kenji SAKAI (Dept. Phys., Tokyo Inst. Technol.)
Tohru TAINO (Fac. Eng., Saitama Univ.)
Fuyuki TOKANAI (Dept. Phys., Yamagata Univ.)
Satoru YAMADA (JAERI)
Trainees
Ran NAKANO (Dept. Electr. Syst., Saitama Univ.)
Masayo YOSHIDA (Dept. Electr. Syst., Saitama Univ.)
Shota YOSHIMURA (Dept. Electr. Syst., Saitama Univ.)
RIKEN BNL Research Center
Head
Nicholas P. SAMIOS (Director)
Hideto EN’YO (RBRC Associate Director)
Tsung-Dao LEE (Director Emeritus)
Experimental
Group Leader
Hideto EN’YO
Deputy Group Leader
Gerry M. BUNCE
Members
Yuji GOTO
Atsushi TAKETANI
Kiyoshi TANIDA

Takashi ICHIHARA
Yasushi WATANABE
Yasuyuki AKIBA

349

Abhay DESHPANDE∗1
Matthias GROSS PERDEKAMP∗1
Tsuguchika TABARU∗3
Kensuke OKADA∗2
Wei XIE∗4

Douglas Edward FIELDS∗1
Masashi KANETA∗2
Osamu JINNOUCHI∗2
Junkichi ASAI∗3
David KAWALL∗4

Visiting Members
Yoshinori FUKAO (Kyoto Univ.)
Takuma HORAGUCHI (Tokyo Inst. Technol.)Kazuyoshi KURITA (Rikkyo Univ.)
Naohito SAITO (Kyoto Univ.)
Zheng LEE (BNL, USA)
Viktor SIEGLE (Univ. Heidelberg, Germany)
Akio OGAWA (BNL, USA)
Dominik GABBERT (Univ. Illinois, USA)
Kenichi NAKANO (Tokyo Inst. Technol.)
TheoryGroup Leader
Larry MCLERRAN
Deputy Group Leader
Anthony J. BALTZMembers
Steﬀen A. BASS∗1
Takashi IKEDA∗3
Sangyong JEON∗1
Yukio NEMOTO∗2
Stefan KRETZER∗2
Mikhail A. STEPHANOV∗1
Ubirajara van KOLCK∗1
Tilo WETTIG∗1
Norikazu YAMADA∗2
Sinya AOKI∗1
Takeshi YAMAZAKI∗2
Takumi DOI∗3
Shoichi SASAKI∗4

Christopher DAWSON∗4
Thomas BLUM∗4
Alexander KUSENKO∗1
Jun-ichi NOAKI∗2
Thomas SCHAEFER∗1
Takanori SUGIHARA∗3
Peter PETRECZKY∗4
Werner VOGELSANG∗4
Taku IZUBUCHI∗1
Kei IIDA∗4
Yoshitaka HATTA∗3
Feng YUAN∗1

Visiting Members
Miklos GYULASSY (Columbia Univ., USA)
Robert L. JAFFE (Massachusetts Inst. Technol., USA)
Robert MAWHINNEY (Columbia Univ., USA)
Edward SHURYAK (State Univ. New York, Stony Brook, USA)
Shigemi OHTA (KEK)
Hiroshi YOKOYA (Hiroshima Univ.)
Konstantinos ORGINOS (Massachusetts Inst. Technol., USA)
Koichi HASHIMOTO (Kanazawa Univ.)
Tetsufumi HIRANO (Columbia Univ., USA)
Administration
Pamela ESPOSITO (Secretary)
Rae GREENBERG (Assistant)
Tammy Anne STEIN (Secretary)
Taeko ITO (Secretary)
Linda SALLUSTIO (Secretary)
Administrative Manager
Kiyofumi TSUTSUMI

350

Deputy Administrative Manager
Chiharu SHIMOYAMADA
Jun NAKAMURA∗1∗3RHIC Physics Fellow, ∗2 Research Associate,
Special Postdoctoral Researcher, ∗4 RIKEN BNL Fellow

SAFETY DIVISION
Head
Hiroshi SAWA
Deputy Director
Masayuki SHIMAGAKI
Yasuhide MATSUZAWA
Makoto MIYAGAWA
Laboratory Safety Section
Head
Yoshitomo UWAMINO
Members
Yuji NAKASHIMA
Hajime YOSHIKI

Shigemi SHINOHARA

Research Ethics Section
Head
Satoru KAGAYA
Members
Akira OZAKI
Kazunori TAGUCHI
Ritsuko NAKAGAWA

Hiroko KATOU
Shigeki ASAKAWA

351

AUTHOR INDEXABE Tomoko

阿部知子

AIDALA Christine

130, 131, 132, 133, 134, 135,

BLUMENFELD Yorick

136, 137, 138

BOWEN Matt D.

208

BOYLE Kieran

53

66

235

AIHARA Toshimitsu

藍原利光

3, 251

BOYLE Peter A.

AKAISHI Yoshinori

赤石義紀

32

BRAVAR Alessandro

224, 226

209, 210, 213, 215, 217,BUENKER Robert J.

81, 82, 93

218, 223, 227, 231, 235

BUNCE Gerry

AKIBA Yasuyuki

秋葉康之

205

224, 226AKIYAMA Kazuhiko

秋山和彦

107

BUTSYK Sergey

213, 215, 223

AKIYAMA Takahiro

秋山隆宏

69, 70, 144

CAI Xiangzhou

蔡

秋吉啓充

48, 49CAMPBELL Chris M.

AKIYOSHI Hiromichi
ALEKSEEV Igor G.

224, 226

ALFORQUE Rudolfo

238

AMANO Ryohei

天野良平

CHEN Jingen

金根

55

CHEN Jinhui

金

55

157

CHEN Wei

91

安藤剛三

ANDO Yoshiaki

安藤嘉章

AOI Nori考

青井54, 62知見康弘

85

CLARK Mike

205

CLOET Ian C.

33

219

COHEN Saul D.

205

青木慎也

189

AOYAMA Shigeyoshi

COOK Jonathan M.
CRISTIAN Cailan

205

CSATLÓS Margit

46

青山茂義

20, 2161, 100, 159, 163
99

荒川洋平

ARIYOSHI Seiichirou

有吉誠一郎

ASAHI Koichiro

旭

耕一郎

ASAI Junkichi

浅井淳吉

144

CSIGE Lóránt

46
出道仁彦

DESHPANDE Abhay

206, 211, 235, 241

DHAWAN Satish

224, 226

60, 61, 83, 100, 159, 163,

DINCA Dan.-Christian66

166, 169

DINH DANG Nguyen

22, 23

227, 231, 235

DOI Takumi

土井 身

ASAI Keisuke

浅井圭介

87, 89DOMBRÁDI Zsolt

浅井雅人

107

DONG Zhihua

213, 215, 223

BABA Hidetada

馬場秀忠

BAZIN Daniel

EATON Gordon H.

46, 48, 51, 52, 53, 54, 56,

ELEKES Zoltán41, 43, 45, 46, 50, 52, 53, 54, 58, 62,

EMORI Shoken

江守昭憲

EMOTO Takashi

江本

53

BELKIN Richard

238

EN’YO Hideto

延與秀人

74, 7565, 73
166, 169

241

ENDO Kazutoyo

BENTZ Wolfgang

13, 33ENOMOTO Shuichi

71

77, 139, 140, 227, 228, 230,

遠藤和豊

120

榎本秀一

103, 105, 107, 109, 113,

201

114, 115, 116, 117, 118,

44, 50, 58

119, 120, 121, 122, 123,

BERRUTO Federico
BLUM Tom隆

231, 233, 237, 247

BENNETT Robert

BISHOP Shawn

60, 61, 83, 100, 159, 163,

209, 210, 211

38, 40, 42, 66

BEAUMEL Didier

32

土手明伸

38, 40, 41, 42, 43, 44, 45,

208

BAZILEVSKY Alexander

41, 43, 45, 46, 50, 52

167

57, 59, 62, 65, 67, 68, 72
BAUER Frank

198

205

DOTÉ Akinobu
EADES John204

41, 43, 52, 54, 62, 65

DEMICHI Kimihiko

ASAI Masato
BÄR Oliver44, 66200

新井崇雅

AVERBECK Ralf

205

203, 204

青木保道

ARAKAWA Yohei

CHIMI Yasuhiro

178, 287, 293
青木真由美

ARAI Takamasa

254, 262

51, 52, 53, 54, 62, 65, 66, 176,
青木和也

AOKI Yasumichi

千葉好明

CHRIST Norman H.

AOKI Kazuya
AOKI Sinya

140

CHIBA Yoshiaki

38, 39, 40, 41, 42, 43, 44, 48, 49,

AOKI Mayumi

66

205

117, 118

AMIR AHMADI Hamid Reza
ANDO Kozo

CHEN Dong55

翔舟

195, 200, 201

124, 125, 249iFÜLÖP Zsolt

41, 43, 45, 46, 49, 50, 52, 54, 62, 73

FANG Deqing

方FIELDS Douglas E.

GROSSE PERDEKAMP Matthias

淵 好秀

172

GUILHERME Amadio

FUJII Hirotsugu

藤井宏次

192

GUIMARÃES Valdir

FUJII Kazuyuki

藤井和行

233

GULYÁS János

46
威

FUJIKAWA Hisashi

藤川尚志

68, 73, 142, 172

GUO Wei

FUJIMAKI Masaki

藤巻正樹

3, 5, 256, 258, 281

HABA Hiromitsu

FUJINAWA Tadashi
FUJITA Kunihiro
FUJITA Shin藤田139, 227, 228, 230, 233,

藤原康平

42

福田直樹

FUKAO Yoshinori

211

深尾祥紀

FUKINISHI Nobuhisa

HACHIYA Takashi

蜂谷

HAEBERLI Willy

224, 226HAGIWARA Kaoru

萩原 薫

189

浜垣秀樹

215, 247

原

249

光雄

HARANO Hideki

75

原野英樹

FUKUCHI Tomonori

福地知則

59, 67, 68, 72

HASAMA Masako

福田光順

47

HASEBE Hiroo38, 39, 40, 41, 43, 46, 53,

218

崇

HAMAGAKI Hideki
HARA Mitsuo
281

福西暢尚

福田直樹

69, 70, 103, 105, 107, 109,
112, 117, 118, 119, 121,FUKUDA Mitsunori
FUKUDA Naoki

55

羽場宏光

122, 123, 124, 249, 260

237
FUKADA Naoki

59, 63

152

260

新

郭

208, 240, 245

68, 737, 269, 283

藤縄 雅

藤田訓裕

FUJIWARA Kohei

208, 209, 210, 211, 220, 227,

後藤雄二

231, 235, 241, 247

214, 235

FUCHI Yoshihide

GOTO Yuji

47, 55清挾間昌子

115, 116

長谷部裕雄

264, 266

HASEGAWA Hirokazu

38, 40, 41, 42, 43,

長谷川浩一

54, 62, 148, 287, 293, 295
FUKUNISHI Nobuhisa

福西暢尚

52, 54, 62, 65

3, 5, 129, 130, 131,

HASEGAWA Hiroko

132, 134, 136, 137,

HASEYAMA Tomohito

109

長谷川浩子

60, 61, 83, 100,

長谷山智仁

159, 163, 166

138, 172, 260, 264,

FUKUSHIMA Kenji
FUKUZAWA Seiji

HASHIMOTO Koichi

橋本耕一

199

283

HASHIMOTO Takashi

橋本尚志

59

HASHIMOTO Yoshiko

橋本佳子

40, 50194

福嶋健二

FUKUYAMA Yoshimitsu

268, 275, 277, 279,

福山祥光

98, 995

福澤聖児

HASHIMOTO Yukio
HASUKO Kazumi

橋本幸男

FUKUZUMI Masafumi

福住正文

85

HATAKEYAMA Atsushi

FURUKAWA Takeshi

古川 武

99

HATANAKA Kichiji

FUTAKAMI Udai
GÁCSI Zoltán54, 62

二上宇内

46

GABBERT Dominik

245

152

HATANO Michio

波多野道夫

154

HATSUDA Tetsuo

初田哲男

193

HATTA Yoshitaka

八田佳孝

194

66

HATTORI Toshiyuki

服部俊幸

GANETIS George

238

HAYASHI Yoriko

依子

GARDNER Matthew D.
GELBERG Adrian
GIBELIN Julien
GILL Ron林

HAYASHIZAKI Noriyosu

205

HE Jianjun

168

何

99

畠山 温

畑中吉治

GADE Alexandra
GARA Alan

30

245

蓮子和巳

238, 301, 303

132, 136, 137
301, 303

林崎規託

56, 57, 59, 63, 68, 73, 142, 172,

建軍

173

41, 4345, 50, 52, 53, 58, 65, 148

HEUSER Johann M.
HIGAKI Hiroyuki

224, 226

GLASMACHER Thomas

27, 66

GOMI Tomoko

38, 40, 41, 42, 43, 48, 49, 50,

五味朋子

76, 139, 227, 228, 230, 233, 237
167

桧垣浩之

HIGURASHI Yoshihide

3, 5, 48, 49, 54, 62,

日暮祥英

251, 260

52, 53, 54, 62, 65

HIRAI Masanori

平井正紀

185, 188

GONAI Takeru

郷内

138

HIRANO Tetsufumi

平野哲文

187

GONO Yasuyuki

郷農靖之

57, 59, 68, 124, 125

HIRUNUMA Rieko蛭沼利江子

119, 120, 121, 122,

GONO Yasuyuki

郷野靖之

56

GOTO Akira

後藤

GOTO Shin-ichi

ii

彰

武

3, 5, 264, 275, 277, 279, 281,

123, 124
HOEFERKAMP Martin

235

283, 285

HOKOIWA Naho

鉾岩奈穂

69, 70

HONDA Chikako

本田智香子

後藤真一

56, 57, 59, 67, 72
120

HONDA Ichiro

本多一郎

134

ISHIMOTO Shigeru

HONMA Michio

本間道雄

27, 29ISHIYAMA Hironobu

HORAGUCHI Takuma

洞口拓磨

HORI Masaki

167

堀

正樹

HORIBATA Takatoshi
45

HORVÁTH Dezsö

167
細井基興

HUANG Haixin

226

55, 58ICHIHARA Takashi

市原

市川雄一

IGARASHI Akinori

IIDA Kei

15, 16

ITO Sachiko

伊藤祥子

71, 260
35, 36, 152

伊藤圭介

IWAI Yoshio

228

岩淵龍也

90, 91

岩井良夫

45, 46, 47, 48, 49, 50, 51,

岩佐直仁

IWASAKI Hironori

50, 51, 52, 54, 56, 57, 58,

45, 67, 68, 69, 70, 72

62, 65, 66, 67, 72, 173,48, 54, 58, 62, 176, 178
79, 80

五十嵐明則

198

飯田英明

18, 19374, 75

岩崎雅彦

IWASAKI Norio

岩崎紀夫

115

IWASE Akihiro

岩瀬彰宏

85

IWASE Naohito

岩佐直仁

62

IWATA Tadao

168

飯村秀紀

176, 178
IWASAKI Masahiko

113, 114, 124

226

飯田 圭

39, 41, 43, 44, 45, 48, 49,

岩崎弘典

44, 45

五十嵐香織

IIMURA Hideki

伊藤 誠

IWASA Naohito

180, 247

卓

井手口栄治

家城和夫

IIDA Hideaki

20, 21

板垣直之

ITO Makoto

54, 58, 172

ICHIKAWA Yuichi

IGO George

59

石山博垣

IWABUTI Tatsuya
90, 91, 92, 93, 94

星野正光

HOSOI Motooki

IGARASHI KaoriITAGAKI Naoyuki

ITOH Keisuke

HOSHINO Masamitsu

IEKI Kazuo

30

堀端孝俊

HORVÁTH Ákos

IDEGUCHI Eiji

209, 210, 243

150

石元 茂

101

岩田忠夫

IWATA Yoshiyuki

49

岩田佳之

IIZUKA Yasutaka

飯塚泰貴

115

IZAWA Masaaki

伊澤正陽

299

IKAWA Hidenori

井川秀徳

269

IZUBUCHI Taku

出渕199, 202

卓

IKEDA Kiyomi

池田清美

15, 20, 21, 24, 26

IZUMI Hideaki

出水秀明

99

IKEDA Naomi

池田直美

86

IZUMI Masako

泉

129

IKEDA Takashi

池田

191

IKEDA Takuichiro

貴JAIN Animesh

90, 91, 273

池田時浩

IKEGAMI Kumio

池上九三男

泉川卓司

47, 55

陣内 修

224, 226, 247

IZUMIKAWA Takuji
35

池田拓一郎

IKEDA Tokihiro

雅子

238

JINNOUCHI Osamu

281, 283, 285, 286

JOÓ Balint

205

IKEZAWA Eiji

池沢英二

3, 5, 7, 260

JUHÁSZ Bertalan

IMAI Nobuaki

今井伸明

38, 39, 40, 41, 42, 43, 44, 48,

JUNG Chulwoo

49, 50, 52, 54, 62, 65

KAGEYAMA Kensuke

蔭山健介

84

IMAO Hiroshi

今尾浩士

74, 75KAGEYAMA Tadashi

影山

3, 5, 271

INABE Naohito

3, 5, 86, 264, 271, 277, 279

稲辺尚人

INAMURA Takashi Thomas
INOUE Masato

ISHIDA Carolina

249

233

井上泰吉

ISHIBASHI Kenichi

卓

167

井上正人

INOUE Yasuyoshi

稲村

67

ISHIDA Carolina Midory

72

ISHIDA Katsuhiko

石田勝彦

74, 75ISHIDA Yoshihisa

石田佳久

161, 164, 168, 170

ISHIHARA Masayasu

石原正泰

69, 70, 103, 144

加治大哉

KAJIHARA Fukutaro

梶原福太郎

213, 215, 223

KAKUTANI Nobukazu

角谷暢一

289, 291, 295

KALINKA Gábor

KAMBARA Tadashi

神原

KAMEDA Daisuke

亀田大輔

KAMEYA Toshiaki

亀谷壽昭

KAMIGAITO Osamu

上垣外修一

KAMIHARA Nobuyuki

神原信幸

121

KANADA-EN’YO Yoshiko

198

KANAI Yasuyuki

ISHIKAWA Tomoko

金井保之

107

石川智子

3, 5, 250, 262, 275
212, 243

延與佳子

17, 2584, 90, 91, 92, 94, 95, 96,
161

41, 43, 53, 54, 58, 62

石川和宏
石川法人

132

44, 49, 52, 54, 60, 62
石井伸昌

ISHIKAWA Norito

60, 61, 83, 100, 111, 159,

38, 39, 40, 41, 42, 43,

石井理修

石井康雄

84, 85, 94, 161

正163, 166ISHII Nobuyoshi
ISHII Yasuo

157

50

ISHII Noriyoshi

ISHIKAWA Kazuhiro

正

KALANTAR-NAYESTANAKI Nasser

123

石橋健一

KAJI Daiya

167

205

KANAVETS Vadim P.

85

KANAYA Takeshi

59

KANAYAMA Yousuke

226

金谷健至

137

金山洋介

117, 118

iii

KANEKO Emi

41, 43金子恵美

KANETA Masashi
KANNO Shouko

菅野祥子

KANO Hiroyuki

狩野博之

KANODA Kazushi
KANOH Hiroki

小林清志

5

小林 稔

16

41, 43, 45, 48, 51, 52, 54,

KOBAYASHI Tohru

小林9962, 65, 66

KOBAYASHI Tomohiro

139, 227, 228, 230, 233, 237

KOBAYASHI Toshio

小林俊雄

38, 39, 40, 42, 174

KOBAYASHI Yoshio

小林義男

60, 61, 83, 100, 111,

KOHAMA Akihisa

小濱洋央

18

271, 273, 275, 277, 279, 281

KOHARA Shigeo

小原重夫

3, 5

138

KOIKE Takeshi

15, 2697, 161片山一郎

KATO Go60, 61, 83, 100, 111, 159, 163, 166

KATO Mineo加藤岑生

74, 75

KATO Seigo

加藤静吾

56, 57, 59, 63, 172, 173

KAWABATA Takahiro
KAWAGUCHI Takeo

川口武男

KAWAI Kiyohiro

KOTAKA Yasuteru
KOURA Hiroyuki

273

KOYAMA Ryo

99

川合清裕
河合祥子

KAWALL David

240, 241
河村成肇

74, 75KAWAMURA Tomoyuki

川村知行

59

KAWASAKI Hiroaki
KAWASAKI Katsunori

KIBE Michiya

52, 53, 54, 62, 65, 66, 67,
72, 161, 176, 178, 287, 289,
291, 293, 295, 296, 297
KUBOKI Hironori

久保木浩功

35, 36, 156, 157

KUBONO Shigeru

久保野

46, 48, 51, 54, 56, 57,

茂142, 172, 173
KUBOTA Satoshi

249

KUDO Hisaaki

268

窪田 聡

久保山智司

86

69, 70工藤久昭

KUDO Katsuhisa

工藤勝久

75

59, 63

KUDOH Takashi

工藤 隆

152

87, 89KUMAKI Takuya

熊木卓也

289

季村峯生

81, 82, 93

KUMANO Shunzo

熊野俊三

188

木村修一

113, 114, 115, 116

KUNIBU Makoto

國分48, 54, 62

205

KIM Jong Chan

金 鍾贊

KIMURA Kazuie

木村一宇

KIMURA Mineo
KIMURA Shuichi

KINUGAWA Hiroto
KISHIDA Takashi

46

衣川裕人
岸田

隆

41, 43, 52, 68, 142, 173

KITAJIMA Masashi

北島昌史

92

KITAMOTO Yusuke

北本優介

109

清道明男

KOBAYASHI Hiroshi

iv

111, 112
38, 39, 40, 41, 42, 43, 44,

KUBOYAMA Satoshi

菊永英寿

KIM Changhoan

KIYOMICHI Akio

久保謙哉
久保敏幸

3, 5, 251, 260

134

郁

KIKUNAGA Hidetoshi

KUBO Kenya M.
KUBO Toshiyuki

58, 59, 62, 63, 68, 73,

60, 61, 83, 159, 163, 166

菊池

46

183

56, 57

木寺正憲

木島 剛

KIKUCHI Kaori

227, 228

224, 226

木部道也

KIDERA Masanori
KIJIMA Go

224

100

川崎克則

川崎健夫

KHODINOV Alexander

9, 69, 70

3, 47

小山 亮

KPONOU Ahhovi

87, 895

小高康照

41, 43

河崎洋章

KAWASAKI Takeo

71, 254, 299

忠

越水正典

小浦寛之

KRETZER Stefan

KAWAMURA Naritoshi

KURAKADO Masahiko
KURAMASHI Yoshinobu

誠

倉門雅彦
藏増嘉伸

KURATA-NISHIMURA Mizuki

49

144
203

倉田-西村美月

56, 57,59, 63,

216, 247

小林 寛

67, 7238, 40, 41, 42, 43, 44, 45,

KRASZNAHORKAY Attila

45, 52, 58

KAWAI Shoko

小関

174
112

小松原哲郎

50, 53, 54, 62, 148
KOSHIMIZU Masanori

川口義弘

91, 95, 167

小牧研一郎

近藤洋介

35, 36, 152, 156, 157,

川畑貴裕

KAWAGUCHI Yoshihiro

KOMAKI Ken-ichiro

KOMATSUBARA Tetsuro

KOSEKI Tadashi
289

加藤義金

84, 161

小島隆夫

KONDO Yousuke

70

鹿取謙二

67, 72

小池武志

KOJIMA Takao M.

KATAYAMA Ichiro

KATOU Yoshikane

258

258, 260, 264, 266, 268, 269,
霞 正一

3, 5,
256,

3, 5, 7, 86, 87, 89, 251, 256,

加藤幾芳

KATORI Kenji

小林-込山美咲

KOBAYASHI-KOMIYAMA Misaki

249

笠松良崇

加瀬昌之

加藤 剛

8, 250112, 159, 163, 166

45, 47, 55, 70, 140

KASAMATSU Yoshitaka

KASUMI Masakazu

徹

小林知洋

243

稼農広樹

KASE Masayuki

102

鹿野田一司

KANUNGO Rituparna

KATŌ Kiyoshi

KOBAYASHI Kiyoshi
KOBAYASHI Minoru

221, 222

金田雅司

68, 142
KURITA Kazuyoshi

栗田和好

41, 43, 44, 50, 51, 52,

54, 58, 62, 65, 71, 148,

MAWATARI Kentarou

224, 226

MAWHINNEY Robert D.

189

馬渡健太郎

205

KURODA Naofumi

黒田直史

167

McLERRAN Larry

191

KUROKAWA Meiko

黒川明子

46, 49, 50, 51, 58, 67,

MENGONI Alberto

39

72, 142MESSCHENDORP Johannes Gerhardus

KUROSAWA Masahiro
KUSAKA Kensuke

日下健祐

KWEON MinJung
LAWLEY Sarah

100

黒沢雅宏

MICHIMASA Shin’ichiro

51, 52, 54, 56,

293, 295, 296, 297

57, 59, 62, 65,

243

67, 68, 72, 73,

13

173

LEE Chun-Sik

李春植

56, 57, 59, 63

MIKAMI Hideo

李柱漢56, 57, 59, 63

MINEMURA Toshiyuki

LENZ Frieder

34

65
MITCHELL Jeﬀery T.

140, 224, 226, 227, 231

236

MITSUGASHIRA Toshiaki
MITSUNOBU Satoshi

63

59

MIURA Motooki

LIEBERMANN Hans-Peter82

MIYAKAWA Kazutaka

LIU Xin

LIU Zhong49

LOZOWSKI William

淳

111

宮沢

豊

MIYOSHI Hisanori

三好永哲

宮崎

春旺

55

国亮

55

MIZOI Yutaka

297

55

MIZUKAMI Eriko

226, 238

MIZUSAKI Takahiro

MADOKORO Hideki

間所秀樹

余

11

MAEDA Yukie

前田幸重

36, 157

MAETA Hiroshi

前田裕司

233

MAKDISI Yousef I.

MOHRI Akihiro

毛利明博

MOON Jun Young

文

157

MORIMOTO Kouji

丸田一成

135

MORINOBU Shunpei

MASUDA Hideki

益田秀樹

90, 91MORITA Kosuke

MATSUDA Yasuyuki
MATSUI Nobuyuki

5

益田邦和

升井洋志

MOTIZUKI Yuko
74, 75

松田恭幸
松井信行

松本謙一郎

MATSUO Keiji

109

松尾由賀利

MATSUOKA Keisuke

松浦妙子

MATSUZAKI Teiichiro

173

67, 69, 70, 72, 103, 144

森本幸司
森信俊平

森田浩介

森脇喜紀

望月優子

MOTOBAYASHI Tohru

9969, 70, 103, 144
98

11

本林 透

1, 38, 40, 41, 42, 43,
44, 45, 46, 48, 49,

120

50, 51, 52, 53, 54,

98, 99, 140
120

本村信治

103, 124, 125, 127

MUELLER Wilhelm F.

66

MURAKAMI Hiroyuki

村上浩之

54, 6248, 52, 54, 62, 65

MURAKAMI Tetsuya

村上哲也

146

74, 75

MURATA Jiro

130

松山裕一

松崎禎市郎

148, 176, 178, 287
MOTOMURA Shinji

193

松山知樹

MATSUYAMA Yuuichi U.

58, 71

斉森川恒安

58, 62, 65, 66, 142,

松岡圭介

MATSUYAMA Tomoki

56, 57, 59, 63, 172

50, 58

MATSUMOTO Ken-ichiro
松尾啓司

森川

MORIWAKI Yoshiki

26

95, 96, 167

俊永

MORIKAWA Tsuneyasu

MARUTA Issey

MASUDA Kunikazu

27, 29水崎高浩

MORIKAWA Hitoshi

208, 224, 226

116

水上恵理子

MARDANPOUR Hossein

MATSUURA Taeko

60, 61, 83, 100, 111, 159,

173, 287, 289, 291, 295, 296,

溝井 浩

MACKAY William W.

MATSUO Yukari132
163, 166

MA Chunwang

MASUI Hiroshi

59

226

MA Guoliang
MA Yugang67, 72

92

宮武宇也

MIYAZAWA Yutaka

MIYAZAKI Jun

205

46

38, 40, 41, 42, 43, 54, 62

宮川一尚

宮本佑二

MIYATAKE Hiroari

168

122

聖

三浦元隆

MIYAMOTO Yuji

53

LIOUBIMOV Vladimir249

277, 279

密本俊典
光延

LICHTENTHÄLER Rubens

LIU Guofeng

三頭聰明MITSUMOTO Toshinori

205

LICHITENTHALER Rubens Filho

LIMA Victor

41, 43, 46, 48, 49,

峯村俊行

205

93

LIAO Xiaodong

281

三神英夫

51, 52, 54, 58, 62,

LEVKOVA Ludmila
LI Zheng

157
41, 43, 46, 48,

176, 178, 287, 289, 291,

LEE Ju-Hahn

LI Yan

道正新一郎

村田次郎

159, 163, 166v

MUTO Ryotaro

武藤亮太郎

MYO Takayuki

明

NAGAE Daisuke

77

OHIRA Seiko26

孝之60, 61, 100, 111, 159, 163,

長江大輔

102

大平聖子

OHKI Tomonori

3

大木智則

OHNISHI Hiroaki

76, 139, 227, 228, 230,

大西宏明

166

233, 237

NAGAI Takahiro -H.

永井崇寛

188

OHNISHI Jun-ichi

大西純一

281, 283, 285

NAGAME Yuichiro

永目諭一郎

107

OHNISHI Tetsuya

大西哲哉

45, 47, 50, 52, 55, 69, 70,

NAGAMI Masakazu

永見将和

289
OHNISHI Tetsuya

大西哲也

NAGAMINE Kanetada
NAGASE Makoto
NAKAI Yoichi

3, 5, 281

長瀬 誠

NAKAGAWA Takahide

71, 72, 146, 150

74, 75

永嶺謙忠

3, 5, 251, 260

中川孝秀

84, 90, 91, 92, 95, 96, 161

中井陽一

NAKAJIMA Shinpei

中島真平

55

NAKAMURA Masato

中村仁音

71

NAKAMURA Satoshi N.

中村 哲

75

OHNO Masashi

144

大野雅史

OHSHIRO Yukimitsu
OHTA Hirofumi

67
5, 253, 254

大城幸光

19

太田寛史

OHTA Koichi

太田浩一

34

OHTA Ryuichi

太田隆一

5

OHTA Shigemi

太田滋生

200, 205

NAKAMURA Takashi

中村

54

OHTAKE Masao

NAKAMURA Takashi

中村貴志

97, 161, 168, 170

OHTANI Munehisa

大谷宗久

192

NAKAMURA Takashi

中村隆司

38, 39, 40, 41, 42, 43,

OHTANI Shunsuke

大谷俊介

97, 16144, 48, 50, 53, 58, 62,

OHTSUBO Takashi

大坪47, 55

隆

286

大竹政雄

隆

66, 148, 174

OHTSUKI Tsutomu

大槻 勤

249

NAKAMURA Takeshi

仲村武志

5

OIZUMI Masafumi

大泉匡史

156

NAKANISHI Takashi

中西 孝

249

OKA Katsumi

岡

克己

86

OKA Makoto

岡

真

198

NAKANO Ken’ichi
NAKAO Taro44, 50中尾太郎

NAKATSUKASA Takashi
NARA Yasushi

209, 210, 220

中野健一

奈良

中務 孝

187

寧

NARUKI Megumi

成木

NASS Alexander

224, 226NIIGAKI Megumi

新垣

恵
恵

NIIKURA Megumi

新倉

潤

NISHIDA Minoru

西田稔

208, 209, 210

岡田邦宏

97, 161, 168

OKAJO Aya彩

95

OKAMURA Hiroyuki

58, 67, 72, 73
5

信時

NODA Koji

野田耕司

NOGI Mitsuko

OKAMURA Masahiro

119

OKIYAMA Kaho

OKUMURA Toshifumi

289

実

138

岡村昌宏

238, 301, 303

OLLIVER Heather
王

ONISHI Takeo K.

NONAKA Hiroshi

野中弘志

111

ONO Fumihisa

NOTANI Masahiro

野谷将広

39, 41, 43, 45, 51, 52, 54,

ONO Mari56, 57, 58, 59, 62, 63, 65,

ORGINOS Kostas

68, 172, 173

OSAWA Kenji

198
116

奥村俊文
奥山利久

惠仁

41, 43, 44, 51, 52, 65

大西健夫

小野文久

大野真里

85

200, 201

大澤健治

135

小田切淳一

256

OSHIMA Nagayasu

大島永康

小田原厚子

59, 68, 124

OSHIMA Sachiko

大島佐知子

OSHIRO Yukimitsu

大城幸充

小川暁生

245

荻原

8, 101

清OHARA Masako

小原雅子

40

OHATA Shigeki

大畑茂樹

123

OHIRA Hideharu
OHIRA Hitomi

vi

大平秀春
大平仁美

86
152

41, 43, 44, 65

118

ODAHARA Atsuko
OGAWA Akio

295

66

ODAGIRI Jun-ichi

OGIWARA Kiyoshi

44, 503, 5, 281, 283, 285

奥野広樹

OKUYAMA Toshihisa
ONG Hooi Jin

35

沖山香帆

OKUNO Hiroki

90, 91

120
岡村弘之

興治文子

56, 57, 59, 63, 68, 73, 142

161

野木光子

岡城

OKIHARU Fumiko

123

NOBUTOKI Minoru

224, 226

岡田謙介

西村仁志

西尾和之

20, 21

岡田裕美

OKADA Kensuke

西村俊二

西尾和人

岡部成玄

OKADA Hiromi
OKADA Kunihiro

NISHIMURA Shunji
NISHIO Kazuyuki

OKABE Shigeto

77

NISHIMURA Hitoshi
NISHIO Kazuto

14, 16, 19

95, 161
61, 159, 163, 169
173

OTA Shinsuke

大田晋介

44

OTA Shinsuke

大田晋輔

50, 51, 52, 54, 58, 62, 65, 67,
68, 72, 176

OTOMO Hiromitsu
OTSU Hideaki

大友洋光

大津秀暁

39

86

OTSUKA Takaharu
OYAMA Hitoshi

27, 29, 31

大塚孝治

91, 161

大山 等

SASAKI Yuichirou

OYAMADA Kazuyuki

小山田和幸

3

SASANO Masaki

OYAMATSU Kazuhiro

親松和浩

18

SATO Hiromi

OZAWA Akira

小沢

OZAWA Kyoichiro
OZAWA Shuichi

144

SATO Hiroyuki

佐藤啓之

59

SATO Kiyokazu

佐藤潔和289, 291, 295

215

49

SATO Naoko
SATO Rie

50
195

123

佐藤尚子

116

佐藤理恵

SATO Tadashi

佐藤雅志

132

SATO Wataru

佐藤 渉

83, 109205

SATOU Yoshiteru

佐藤義輝

81, 82, 93

SCHUCH Reinhold

94

PETROV Kostya

SCHUESSLER Hans A.

RAI Sachchida N.

82

REN Zhongzhou

任 中洲

55

SEIDL RaLF

224, 226

SEKIGUCHI Kimiko

ROSER Thomas

226, 238

SEKIGUCHI Yoshihiro

RYKOV Vladimir L.

227, 236, 246

RYUTO Hiromichi

龍頭啓充

SAENMA Hiroshi

佐縁馬

SAIKA Daisuke

雑賀大輔

97

SERATA Masaki

世良田真来

SHEN Wenqing

沈

志岐成友

144

277, 279

SHIMADA Kenzi

島田健司

60, 61, 83, 100, 111, 159,

柴田利明

156

163, 166109

SHIMADA Mamoru

島田51, 52, 53, 54, 58, 62, 65, 73,

SHIMAMURA Isao

島村 勲

79, 80172

SHIMIZU Hirohiko

清水裕彦

144

102

SHIMIZU Noritaka

清水則孝

31

SHIMIZU Tetsuya

清水鉄也

11

137, 138

SHIMIZU Yasuhiro齊藤直人

224, 226, 227, 241

SHIMIZU Youhei

清水陽平
下田

SAITO Takaaki

齋藤孝明

35

SHIMODA Tadashi

齋藤明登

68

SHIMOURA Susumu

152
99

正

下浦

享

146

坂口治隆

SAKAI Hazuki K.

酒井葉月

52

SAKAI Hideyuki

酒井英行

35, 36, 152, 154, 156, 157

38, 39, 40, 41, 42, 43,
45, 46, 48, 49, 51, 52,

36, 154, 157

坂口聡志

54, 58, 59, 62, 65, 67,
68, 72, 173, 176

269

阪本敦彦

SHINOHARA Atsushi

篠原

SHINOZAKI Wakako

篠崎和佳子

168

SAKAMOTO Hisao

坂本久雄

260

SHUESSLER Hans A.

SAKAMOTO Koichi

阪本浩一

136, 138

SOHLER Dóra50

3, 5, 157, 262, 275,

SONI Amarjit

201

277, 279, 281

SONODA Tetsu

園田 哲

SPINKA Harold

224, 226

坂本成彦

152

SAKEMI Yasuhiro

酒見泰寛

SAKUMA Fuminori

佐久間史典

77

STEPHENSON Ed

SAKURAGI Yukinori

櫻木千典

17

SU Qianmin

前敏

SAKURAI Hiromu

弘

SUDA Kenji

須田健嗣

櫻井博儀

102

清水康弘

SAITOH Akito

SAKURAI Hiroyoshi

86

修

SAITO Naohito

桜井

289

嶋田 守

SHIMADA Osamu

130, 131, 132, 134, 136,

SAKAMOTO Naruhiko

243

SHIBATA Toshi-Aki
SHIKI Shigetomo

斉藤宏之

SAKAMOTO Atuhiko48, 49, 54, 62

55

文

138, 264, 266, 268, 275,
寛

斎藤軍治

SAKAGUCHI Satoshi

269

関口芳弘

SAITO Hiroyuki

SAKAGUCHI Harutaka

35, 36, 157

関口仁子

131, 132, 134, 136, 137,

38, 40, 41, 42, 43, 46, 48, 50,

齋藤明登

SAITO Gunzi

3, 5, 87, 89, 129, 130,50, 53, 148

245

RESCIA Sergio

SAITO Akito

35, 36, 156

笹野匡紀

佐藤広海

70, 72
小沢恭一郎

PETRECZKY Peter36, 157, 174

笹本良子

45, 46, 47, 52, 55, 65, 67, 69,

小澤修一

PERERA AloyPICHL Lukas

顕273

佐々木雄一朗

SASAMOTO Yoshiko

119
38, 39, 40, 41, 42, 43,

SUDA Toshimi

厚109, 249
47

161

224
55
36, 157

須田利美

44, 45, 48, 49, 50, 51,

47, 55, 67, 69, 70, 71, 72,
146, 150

52, 54, 58, 62, 65, 66,

SUDOH Kazutaka

176, 178, 287, 297

SUEKI Keisuke

須藤和敬

末木啓介

185, 186, 246

69, 70vii

SUGAI Hiroyuki

74, 75

須貝宏行

SUGANUMA Hideo

58, 62, 65, 66, 176

198

菅沼秀夫

TAKI Reiko

瀧

275

玲子

SUGAWARA Kousuke

菅原浩介

55, 58TAKISAWA Aiko

SUGIHARA Takanori

杉原崇憲

190

TAKIZAWA Yoshiyuki

55

滝沢愛子

144

滝澤慶之

SUGIMOTO Satoru

杉本

聡

24

TAMAKI Mitsuru

玉城 充

41, 43, 51, 52, 65, 67, 72

SUGIMOTO Takashi

杉本崇38, 40, 41, 42, 43, 54,

TAMESHIGE Yuji

為重雄司

152

58, 62TAMII Atsushi

SUGIYAMA Masao

杉山正夫

136

TANABE Shinzo

田辺信三

123

田中 大

92

SUMIKAMA Toshiyuki

炭竈聡之

50

TANAKA Hiroshi

SUMIYOSHI Kohsuke

住吉光介

12

TANAKA Kanenobu

SUN Zhiyu

志宇55

SUNO Hiroya

数納広哉

55

田中鐘信

TANAKA Manobu
81

152

民井 淳

227, 233, 237

田中真伸

TANAKA Masahiko H.

59, 172

田中雅彦

SUZUKI Chisato

鈴木千聖

133

TANAKA Nozomi

田中のぞみ

92

SUZUKI Daisuke

鈴木大介

44, 50TANASE Masakazu

棚瀬正和

75

12

TANI Yuki

SUZUKI Hideyuki

鈴木英之

SUZUKI Hiroshi

鈴木58, 66, 176, 178宏

SUZUKI Kazunori

鈴木一典

138

SUZUKI Ken-ichi

鈴木賢一

137

SUZUKI Masaru K.

鈴木

鈴木令子

82, 93SUZUKI Shoji

鈴木祥二

150

SUZUKI Takeshi

鈴木

谷田 聖

233

TANIHATA Isao

谷畑勇夫

45, 46, 47, 55, 58, 65, 67,
72, 140, 150

41, 43, 44, 50

賢

SUZUKI ReikoTERAKAWA Teruhiko

鈴木俊宏

224, 226TERASHIMA Satoru
TERRY J. R.

田原司睦

77, 213, 215, 223, 227

THIES Michael

34

橘

193

THIROLF Peter

46

基

121

田上恵子

THOMAS Antony W.

TAGISHI Yoshihiro

田岸義宏

142

THOMAS Richard

TAKAHASHI Masa

高橋

47

TIAN Wendong

聖

TAKAHASHI Naruto

高橋成人

109

TAKAHASHI Yoshio

高橋嘉夫

122

TAKAHASHI Yoshiyuki

高橋良幸

TAKAHASHI Yutaka

豊

高橋

249

高宮幸一

238, 301, 303

高野淳平

TAKANO Masatoshi

150, 296

161, 168, 170

高峰愛子

TAKAMIYA Koichi

36, 156, 157

10

鷹野正利

13, 33

238

田

55

文

TOGANO Yasuhiro

栂野泰宏

44, 45, 50, 52, 53, 54,

TOGAWA Manabu

外川 学

213, 215, 223, 227

TOGAWA Tadayasu

兎川忠靖

123

58, 62, 65

TOJO Junji

227, 231, 233, 235

東城順治

TOKI Hiroshi

12, 24土岐 博

TOMINAKA Toshiharu

283, 285, 286, 305

冨中利治

TOMITA Masanori

冨田雅典

129

鳥居寛之

91, 167

TAKASHINA Masaaki

高階正彰

17

TORII Hiroyuki A.

TAKATSU Yasumasa

高津康正

138

TORII Hisayuki

50, 71, 140, 146, 150

140, 146

寺嶋 知

66

TABARU Tsuguchika

TAKANO Junpei

39, 48, 49, 53, 56, 57,

高172, 173TACHIBANA Motoi

TAKAMINE Aiko

寺西58, 59, 63, 68, 73, 142,
123

SUZUKI Toshihiro

136

寺川輝彦

TERANISHI Takashi

45, 47, 55, 58

健

SVIRIDA Dmitry N.

TAGAMI Keiko

109

谷 勇気

TANIDA Kiyoshi

鳥井久行

107

TAKEDA Hiroyuki

竹田浩之

TAKEHISA Hinako

竹久妃奈子

TAKEICHI Hiroshige

竹市博臣

124, 125, 126, 127

TSUCHIMOTO Yuji

槌本裕二

213, 215, 217, 223

TAKEMURA Makoto

竹村61, 159, 163

TSUKADA Kazuaki

塚田和明

107

TAKESHITA Eri

竹下英里

TAKETANI Atsushi
TAKEUCHI Satoshi

真

TSUKADA Masamichi

54, 58, 62, 65, 176, 178

TSUKADA Teruyo

聡

viii

土橋隆博

TSUKIORI Noritoshi

233, 235, 237, 243

TSUKUI Masato

41, 43, 44, 45, 46, 48,

129

月居憲俊

津久井正人

5

60, 61, 83, 100, 159, 163,
166

TSUNODA Shigeyuki

289, 291

120

塚田正道

塚田晃代

139, 227, 228, 230, 231,

49, 50, 51, 52, 53, 54,

豊嶋厚史

TSUCHIHASHI Takahiro

41, 43, 45, 48, 51, 52, 53,

竹谷 篤
武内

132

TOYOSHIMA Atsushi

209, 210, 221, 222

角田茂幸

135

TUOZZOLO Joseph E.

238

UCHIDA Makoto

内田 誠

61, 100, 159, 163, 166, 169

UCHIDA Shigeo

内田滋夫

121

YAMADA Kazunari

山田一成

48, 49, 52, 54, 58, 62, 65

YAMADA Norikazu

山田憲和

203

YAMADA Shoichi

3

12

山田章一

内山暁仁

UE Koji

48, 54, 62, 173

YAMAGAMI Masayuki

山上雅之

28

16

YAMAGUCHI Azusa

山口あづさ

205

上

浩二

UEDA Manabu

上田

UENO Hideki

上野秀樹

学

YAMAGUCHI Hidetoshi

166

YAMAGUCHI Kenichi

UESAKA Tomohiro

上坂友洋

226
75

URITANI Akira

瓜谷

UTSUNO Yutaka

宇都野 穣

章

UWAMINO Yoshitomo27

161
38, 40, 53

184

WADA Michiharu

和田道治

WAGNER Marcus

241

山口充孝

142

YAMAGUCHI Takayuki

山口貴之

55, 69, 70

YAMAGUCHI Yoshitaka

山口由高

45, 4797, 161, 164, 168, 170

山根誉久

268

YAMANISHI Hisao

山西久夫

135

YAMASAKI Kousuke

山崎公輔

120

YAMASHITA Kouhei

山下恒平

92

YAMAUCHI Hiromoto

山内啓資

3

99

YAMAZAKI Norio

山崎則夫

172, 17359, 67, 68, 72, 73, 172

YAMAZAKI Takeshi

山

197

若林 功
若林泰生

WAKASA Tomotsugu

若狭智嗣

152

YAMAZAKI Toshimitsu

WAKASUGI Masanori

若杉昌徳

3, 5, 71, 275

YAMAZAKI Yasunori

剛

84, 90, 91, 92, 93, 94,
95, 96, 161, 164, 167,

55

168, 170

王

志剛

167

WATANABE Hiroshi

渡邉寛

WATANABE Kenji

渡辺健司

WANG Zhigang

WATANABE Kiwamu

YAN Tingzhi
41, 43, 60, 61, 68, 83

柳澤善行

52, 53, 54, 56, 57,
58, 62, 65, 68, 73,

173, 253, 254, 273

渡辺伸一

38, 40, 42, 44, 45,
46, 48, 49, 50, 51,

38, 40, 42
254

渡辺真朗

WATANABE Shin-ichi

55

廷志

YANAGISAWA Yoshiyuki

133

渡辺極之

WATANABE Masao

32

山崎敏光
山崎泰規

36, 152, 154

涌井崇志

王

130, 131, 132, 133

山本義治

YAMANE Takahisa

WAKABAYASHI Isao

WAKUI Takashi

301, 303

山本和男

WAKABAYASHI Yasuo

WANG Kun

253

山家捷一

YAMAMOTO Yoshiharu Y.

VINODKUMAR Attukalathil Mayyan

7

58

山口考司

YAMAMOTO Kazuo

22

VOGELSANG Werner

YAMAGUCHI Koji

68, 73, 142

山口英斉
山口建一

YAMAGUCHI Mitsutaka

YAMAKA Shoichi
260

上蓑義朋

VARENTSOV Victor
VINH MAU Nicole

35, 36, 152, 154, 157, 174

101

浦井輝夫

山田康洋

60, 61, 83, 100, 111, 159, 163,

UNDERWOOD DavidURAI Teruo

YAMADA Yasuhiro

111, 112

UCHIYAMA Akito

173

WATANABE Takashi

渡辺 崇

243

WATANABE Tamaki

渡邉

273

251, 260, 264, 266, 268,

WATANABE Yasushi

渡邊 康180, 227, 247

269, 271, 273, 275, 277,

WATANABE Yutaka X.
WEI Yibin

魏WETTIG Tilo

YASADA Yuusuke

224, 226
161, 164

WOOD Jeﬀery226

WU Cuie翠娥

XIE Wei

213, 215, 240

YAGI Eiichi

安井裕之

119

YAZAKI Koichi

矢崎紘一

34

YOKKAICHI Satoshi

四日市 悟

YOKOUCHI Shigeru

横内 茂

YOKOYA Hiroshi

矢花一浩

14, 15, 16, 19

100, 101

矢向謙太郎
薬師寺

77, 247

3, 5, 264, 277, 279, 281,
283

横谷 洋

YOKOYAMA Akihiko

八木栄一

YAKUSHIJI Takashi

146

安田裕介

YASUI Hiroyuki

45, 4769, 70YAKO Kentaro

279, 281, 283, 285, 286,
287

226

YABANA Kazuhiro

3, 5, 7, 71, 124, 125, 129,矢野安重

38, 39, 40, 42, 59

196, 205

WOLLNIK Hermann

XU Hushan

渡辺 裕

YANO Yasushige

55

彬

WHITTEN Chuck
WISE Tom環

YONEDA Akira

35, 36, 156, 157
崇

YOKOYAMA Ichiro38, 40, 42

横山一郎

米田

YONEDA Ken-ichiro

186, 189
249

横山明彦
晃

256

3, 5, 69, 70, 84

米田健一郎

38, 39, 40, 41, 42, 43,
52, 54, 62, 65, 66

ix

YONEDA Satoshi

米田

167

諭

YONEYAMA Katsuyoshi

米山勝美

YOSHIDA Atsushi

敦

吉田

133

45, 51, 54, 62, 69, 70,
161, 170, 180, 287, 289,
291, 293, 295, 296, 297

YOSHIDA Hidetomo
YOSHIDA Koichi

152

吉田英智

45, 46, 49, 53, 67, 72, 176,

吉田光一

178, 180, 287, 289, 291,
293, 295, 296, 297
YOSHIDA Shigeo

130, 131, 132, 133, 134,

吉田茂男

137, 138
YOSHIKI FRANZEN Ken
YOSHIMI Akihiro

167
60, 61, 83, 100, 111, 159,

吉見彰洋

163, 166, 169
YOSHIMURA Takashi

吉村 崇

YOUN Minyoung

尹民榮

YUKI Hideyuki

結城英行

63
249

敦

123

YUN Chong Cheoul

尹 鍾哲

63

ZELENSKI Anatoli

224, 226

YUMOTO Atsushi

湯本

ZENIHIRO Juzo

銭廣十三

146

ZHAO Yu-Liang

趙69, 70宇亮

ZHONG Chen晨ZUO Jiaxu

55

x

左 嘉旭

55

109