RIKEN
Accelerator
Progress Report

2005
vol.

39

BOOK & CD−ROM
独立行政法人理化学研究所
RIKEN

CONTENTS
I.

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

II.

OPERATION OF ACCELERATORSIII.

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

3

RRC operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

AVF operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

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

9

RESEARCH ACTIVITIES

1. Nuclear Physics
16 C inelastic scattering studied with the microscopic coupled-channels method........

11

Coulomb breakup eﬀects on elastic cross section of 6 He+209 Bi scattering near Coulomb
barrier energies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12Reaction cross section described by a black sphere approximation of nuclei . . . . . . . . . . . .

13Study of oxygen isotopes by charge- and parity-projected Hartree-Fock method . . . . . . .

14

Tensor correlation in neutron halo nuclei . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15

Three-body cluster states in 11 C and 11 B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16Alpha particle condensation in 12 C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

17

Molecular-orbital and di-nuclei states of 22 Ne . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18

Many-body correlations among weakly bound neutrons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

19

Calculations of lowest 2+ states of Ni isotopes using quasiparticle random-phaseapproximation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

20Shape coexistence of N = 20 isotopes studied by the Monte Carlo shell model . . . . . . . . .

21

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

22

Origin of J = 0 dominance in two-body random interaction . . . . . . . . . . . . . . . . . . . . . . . . . . .

23

Estimation of ground-state energy and spin-zero dominance . . . . . . . . . . . . . . . . . . . . . . . . . . .

24

Band structure in doubly-odd nuclei with mass around 130 . . . . . . . . . . . . . . . . . . . . . . . . . . . .

25

Backbending phenomena in A ∼ 130 region described using a pair-truncated shellmodel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

26

Self-consistent random-phase approximation at ﬁnite temperature within the
picket-fence model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

27

Eﬀect of thermal pairing within thermal shape-ﬂuctuation model on
giant-dipole-resonance width at low temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

28

Study of nuclear structure change in framework of 3D-CHFB + GCM . . . . . . . . . . . . . . . . .

29

Decay modes of heavy and superheavy nuclei predicted by KTUY mass formula . . . . . . .

30

Development of 2-D supernova model for r-process nucleosynthesis . . . . . . . . . . . . . . . . . . . .

31

2-D simulation of core-collapse supernova explosion caused by anisotropic neutrino
ﬂux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

32

EOS dependence of supernova neutrinos from the collapse of massive stars . . . . . . . . . . . .

33

Momentum correlation in the three-body decay of high-density K̄ nuclear clusters:
N N N K− → N + N + Λ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

34

Shear viscosity coeﬃcient studied by molecular dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35

Color superconductivity and neutron star structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36

The polarized EMC eﬀect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

37

Measurement of the vector analyzing power for the p+6 He elastic scattering at 71 A MeV
using polarized proton solid target . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

38

Inelastic proton scattering of 6 He . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

39

Conﬁrmation of validity of s-wave approximation for 6 Li(d,p0 ) reaction at incident energyof 90 keV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

40

Laser spectroscopy of 10 Be+ in an on-line ion trap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

41

6 He+6 He cluster states in 12 Be via α-inelastic scattering

42..............................

8 Li(α,n)11 B reaction measurement using monolithic silicon telescope..................

43

Elastic scattering and Coulomb dissociation of 8 B on Pb, liquid hydrogen and liquid
helium targets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

44

Proton inelastic scattering of 14 Be . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45

Invariant-mass spectroscopy of 14 Be . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

46

Isoscalar monopole and dipole strengths in 14 O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

47

Decoupling of valence neutrons from core in 17 B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48

Structure of 17 B studied by proton inelastic scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

49

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

50

Inelastic proton scattering of 19 C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

51

In-beam γ-ray spectroscopy of 19 N and 20 N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

52

Study of 22,23 O nuclear structure by 22 O+2 H reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

53

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

54

Coulomb excitation measurement for 18 Ne with precise angular distribution . . . . . . . . . . .

55

Search for low-lying dipole strength in the neutron-rich nucleus 26 Ne . . . . . . . . . . . . . . . . . .

56

Measurement of B(E2; 0+ → 2+1 ) value in

Ne . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

57

Quadrupole collectivity of 28 Ne and the boundary of the island of inversion . . . . . . . . . . .

58

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

59

Progress in analyzing proton resonant states in 22 Mg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60

Measurement of proton transfer reaction 4 He(32 Mg,33 Alγ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

61

26

Alpha inelastic scattering on 32 Mg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

62

Proton inelastic scattering on 32 Mg and 34 Si . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

63

Weak-coupling structure of proton resonances in 23 Al . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

64

β-delayed proton and γ-ray spectroscopy of 24 Si . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

65Investigation of stellar reaction rate for 26 Si(p,γ)27 P by Coulomb dissociation of 27 P . .

66

Measurement of spin and magnetic moment of 23 Al . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

67

32
Magnetic moments of 30
13 Al17 and 13 Al19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

68

Precision measurements of magnetic moments of 31 Al and 32 Al . . . . . . . . . . . . . . . . . . . . . . . .

69

Electric quadrupole moments of 32 Al and 31 Al . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

70

Inelastic proton scattering on neutron-rich nuclei 60 Cr and 62 Cr . . . . . . . . . . . . . . . . . . . . . . .

71

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

72

Development of 134 Ce isomeric beam with spin orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . .

73

Study of high-spin states in 49−51 Ti . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

74

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

75

Observation of second decay chain from 278 113 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

76

Electron scattering from unstable nuclei by novel SCRIT method (III) . . . . . . . . . . . . . . . .

77

Observation of medium modiﬁcations for ρ and ω mesons . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

78

Nuclear mass number dependence of inclusive omega and phi meson productions in
12 GeV p-A collisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

79

Evidence for φ meson modiﬁcation in nuclear medium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

80

Nuclear size dependence of φ meson production via e+ e− and K + K − decay channel in
12 GeV p+A reaction at KEK-PS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

81

Muon catalyzed fusion in non-equilibrium D2 +T2 mixtures . . . . . . . . . . . . . . . . . . . . . . . . . . .

82

Measurement of Doppler broadening width of Kα X-rays from µ− α atoms formed in muon
sticking process of muon catalyzed t-t fusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

83

Dimuon measurement in Indium-Indium collisions at CERN/SPS . . . . . . . . . . . . . . . . . . . . .

84

2. Atomic and Solid-State Physics
Eigenvalues of the time-delay matrix in overlapping resonances . . . . . . . . . . . . . . . . . . . . . . . .

85

Measurement of resonant coherent excitation for channeling Li-like Fe ions using siliconsurface barrier detector target . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

86

Ni-ion-induced charge collection measurements of SiC Schottky barrier diode . . . . . . . . . .

87

Elastic waves from swift heavy-ion irradiations on solids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

88

Synthesis of Au nanoparticles by GeV-ion irradiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

89

Observation of hyperﬁne ﬁeld on 17 N nucleus at P1 center in diamond . . . . . . . . . . . . . . . .

90

Online TDPAC measurements with the 19 F probe implanted in metal oxides . . . . . . . . . .

91

Eﬀects of proton beam irradiation of chalcopyrite-type compound semiconductor solar
cell material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

92

Ultra-short-pulse continuum of ion track and its universality . . . . . . . . . . . . . . . . . . . . . . . . . .

93

Temperature and excitation density dependence of ultrafast luminescence of
ion-irradiated α-alumina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

94

Resonant electron capture and decay for N ions using metal microcapillary targets . . . .

95

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

96

Charge-state correlations in large-angle scattering between Ne ion and Ar atom . . . . . . .

97

Possible scheme for preparing microbeam of slow highly charged ions using tapered glass
capillary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

98

Guiding of slow Ne ions transmitted through nanocapillaries in polymer foils . . . . . . . . . .

100

Measurement of momentum distributions of multiply charged rare gas ions produced byan intense (∼1017 W/cm2 ) laser ﬁeld . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

101

Space-charge shift in motional resonance of Ca+ by simultaneously trapped molecularions in a linear Paul trap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

102

Excitation spectrum of Al atoms in He II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

103

Hyperﬁne-structure spectroscopy of stable 133 Cs atoms in He II . . . . . . . . . . . . . . . . . . . . . . .

104

Research for acceleration of Al by Direct Plasma Injection Scheme . . . . . . . . . . . . . . . . . . . .

105

Shot-to-shot stability of ion generation by solid-state laser . . . . . . . . . . . . . . . . . . . . . . . . . . . .

106µSR study of magnetic property of α-(BETS)2 I3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

107

3. Radiochemistry and Nuclear Chemistry
Preparation of Th target for heavy element studies with GARIS . . . . . . . . . . . . . . . . . . . . . .

109

Search for superheavy-element nuclides for chemical studies using 232 Th+40 Ar
reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

110

Development of online solvent extraction system using microchip . . . . . . . . . . . . . . . . . . . . . .

111

Development of capillary electrophoresis apparatus for heavy actinide chemistry . . . . . . .

112

Development of gas-jet transport system for superheavy element chemistry using the
RIKEN K70 AVF Cyclotron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

113

Distribution coeﬃcients measured with noncarrier tracers of Zr-88 and Hf-175 on TBP
resin in hydrochloric acid and nitric acid solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

114

Eﬀects of milk and soy milk on uptake of trace elements in rats . . . . . . . . . . . . . . . . . . . . . . .

115

Inﬂuence of dopamine on overaccumulation of copper in LEC rats: A proposal . . . . . . . .

116

Investigation of Cu dynamics in Long-Evans Cinnamon rats . . . . . . . . . . . . . . . . . . . . . . . . . . .

117

Diﬀerence in property of skin penetration between 65 Zn(II) ion and its complex topicallyapplied on skin of live hairless mice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

118

Behavior of trace elements and protein contents in livers of zinc-deﬁcient mice . . . . . . . . .

119

Determination of rhenium and technetium in marine algae . . . . . . . . . . . . . . . . . . . . . . . . . . . .

120

Search for metal delivery from nose to brain: A multitracer study . . . . . . . . . . . . . . . . . . . . .

121

Preliminary study of biodistribution of 203 PbCl2 and 203 Pb-DOTMP in mice . . . . . . . . . .

122Comparative study of biotrace elements in bile of rat under oxidative stress . . . . . . . . . . .

123

Eﬄux study of trace elements in a cisplatin-resistant lung cancer cell line using a
multitracer technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

124

Removal of radionuclides from solution by Escherichia coli . . . . . . . . . . . . . . . . . . . . . . . . . . . .

125

Eﬀects of microorganisms on uptake of radionuclides by plants . . . . . . . . . . . . . . . . . . . . . . . .

126

Imaging performance test of prototype model for GREI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

127

Reactions of 57 Mn implanted into solid oxygen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

128

Production of 83 Rb for 83 Kr Mössbauer spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

129

99 Ru Mössbauer and µSR studies of CaRuO
3.........................................

130Eﬀect of heavy-ion-induced DNA damage on response of DNA-dependent protein
kinase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

131

Maximal protection by DMSO in inactivation of mammalian cells exposed to very highLET radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

132

Mutation induction in frozen human cultured cells by low-dose carbon ion
irradiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

133

Study on mutants of Monascus pilosus induced by heavy-ion beam . . . . . . . . . . . . . . . . . . . .

134

In situ visible markers of Arabidopsis for radiation biology . . . . . . . . . . . . . . . . . . . . . . . . . . . .

135

Einkorn wheat mutant, mvp which shows maintained vegetative phase is caused byion-beam-derived mutation of wheat APETALA1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

136

Isolation of morphological mutants of rice induced by heavy-ion irradiation . . . . . . . . . . . .

137

Characteristics of glutinous rice mutants induced by nitrogen-ion beam irradiation . . . .

138

Mutation induction by heavy-ion beam irradiation in daylily, Hemerocallis hybrida . . . .

139

Sterile verbena cultivar produced by heavy-ion beam irradiation and wild species Verbena
peruviana exhibit diﬀerent self-incompatible phenotypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

140

Ion beam sensitivity of ornamental plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

141

Eﬀect of heavy-ion beam irradiation on cyclamen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

142

4. Radiation Chemistry and Radiation Biology

5. Instrumentation
STJ cryogenic detector response to α-particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

143

Mixed-wave RF-application system for Q-moment measurements . . . . . . . . . . . . . . . . . . . . . .

145

Development of recoil particle detector system for proton elastic scattering . . . . . . . . . . . .

146

Neutron polarimeter for test of Bell’s inequality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

147

Improvement of resolving power of multireﬂection time-of-ﬂight mass spectrometer . . . .

148

Development of low-energy muon beam line at the RIKEN-RAL muon facility . . . . . . . . .

149

Particle discrimination using pulse shape analysis in Si detector . . . . . . . . . . . . . . . . . . . . . . .

150

Recent development of liquid hydrogen target . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

151

Development of Self-Conﬁning Radioactive Ion Target (SCRIT) . . . . . . . . . . . . . . . . . . . . . . .

153

High-stability current source for EDM experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

154

RF cavity for spin selection in RIABR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

155

Development of gas degrader and gas scintillation beam monitor . . . . . . . . . . . . . . . . . . . . . .

156

Trapping radioactive Be isotopes using rf ion guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

157

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

159

6. Material Analysis
Hydrogen depth proﬁle analysis of silicone modiﬁed by plasma ion implantation . . . . . . .

161

7. RIKEN-BNL Collaboration
QT resummation in transversely polarized Drell-Yan process . . . . . . . . . . . . . . . . . . . . . . . . . .

163

Soft-gluon resummation for prompt photons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

164

Thermal phase transition of color superconductivity with Ginzburg-Landau action on thelattice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

165

Magnetic vortex in color-ﬂavor locked quark matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

166

Quarkonia correlators and spectral functions on anisotropic lattices . . . . . . . . . . . . . . . . . . .

167

Recent results from unquenched light sea quark simulations . . . . . . . . . . . . . . . . . . . . . . . . . . .

168

Flavor-singlet pseudoscalar meson in two-ﬂavor domain wall QCD . . . . . . . . . . . . . . . . . . . . .

169

Bound state spectrum in ﬁnite volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

170

Study of spin 3/2 pentaquarks in anisotropic lattice QCD . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

171∆I = 3/2 kaon weak matrix elements with non-zero total momentum . . . . . . . . . . . . . . . . .

172

Neutron electric dipole moment from lattice QCD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

173

Status of QCDOC (QCD On a Chip) computer project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

174

Measurement of double helicity asymmetry (ALL ) in π 0 production in proton-proton
collisions at RHIC-PHENIX experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
√Measurement of direct photons in s = 200 GeV p + p collisions . . . . . . . . . . . . . . . . . . . . . .

175
176

Measurement√of transverse single-spin asymmetries with muons in polarized p+p
collisions at s = 200 GeV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

177

Double-spin asymmetry of J/ψ → µ+ µ− in longitudinally polarized p + p collisions at√
s = 200 GeV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

178

0Spin transfer to inclusive Λ hyperons from longitudinally polarized protons at√
S = 200 GeV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

179

Measurementof the mid-rapidity helicity asymmetry of η mesons in pp collisions at√
s = 200 GeV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

180±Charged pion longitudinal double-spin asymmetry AπLL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

181

kT asymmetry in longitudinally polarized pp collisions at PHENIX . . . . . . . . . . . . . . . . . . . .
Double helicity asymmetry in multiparticle production for polarized proton-proton
collisions at PHENIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
√Transverse single spin asymmetries at mid-rapidity at s = 200 GeV in p+p
collisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Spin-dependent fragmentation function measurements at Belle experiment . . . . . . . . . . . .
Polarization measurements of 100 GeV proton beams at RHIC by elastic proton-protonand proton-carbon scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
√Mid-rapidity neutral pion production in proton-proton collisions at s = 200 GeV . . . . .
√Selection criteria of dimuon decay from J/ψ in s = 200 GeV proton-proton
collisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
√Measurement of single electron spectrum in s = 200 GeV p-p collisions at
RHIC-PHENIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

182
183
184
185
186
187
188
189

Measurement of virtual photons at intermediate pT in Au+Au collisions at√
sN N = 200 GeV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
√Prompt photon production in sN N = 200 GeV d+Au collisions at RHIC-PHENIX . . .
√Measurement of neutral pion in sNN = 200 GeV Au+Au collisions at
RHIC-PHENIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

191

Single electron measurement in PHENIX Run-3 d+Au experiment . . . . . . . . . . . . . . . . . . . .

193

Single electron measurement in PHENIX Run-4 Au+Au experiment . . . . . . . . . . . . . . . . . .

194

Measurement of low-mass vector mesons in nuclear collisions at PHENIX . . . . . . . . . . . . .

195

Relative luminosity measurements in a high rate environment . . . . . . . . . . . . . . . . . . . . . . . . .

196

Relative luminosity studies with polarized protons in RHIC Run5 at PHENIX . . . . . . . .

197

PHENIX local polarimeter in 2005 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

198

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

199

Development of the silicon pixel detector for PHENIX at CERN . . . . . . . . . . . . . . . . . . . . . .

200

Evaluation of novel strip-pixel detectors for the silicon vertex tracker at PHENIX . . . . .

201

Silicon stripixel sensor test and fabrication of support frame for silicon pixel detector . .

203

Silicon pixel detector assembly for PHENIX upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

205

Evaluation of pixel readout chip and sensor hybrid for PHENIX upgrade . . . . . . . . . . . . . .

207

Development of PHENIX PIXEL bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

209

Developments and tests of PHENIX pixel detector readout system . . . . . . . . . . . . . . . . . . . .

211

Development of silicon stripixel detector for PHENIX experiment . . . . . . . . . . . . . . . . . . . . .

212

Development of low voltage power supply for PHENIX PIXEL detector . . . . . . . . . . . . . . .

214

Optical alignment system for PHENIX muon tracker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

216

Experimental status of penta quark search via K + p → π + X reaction at KEK-PS
E559 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

218

190

192

Vector meson measurements at J-PARC 50-GeV PS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

219

Mass data processing for RHIC-PHENIX experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

220

Large-scale data transfer in realtime over the Paciﬁc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

222

CCJ operation in 2004–2005 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

224

8. Miscellaneous
Pumping 229m Th by hollow-cathode discharge [III] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IV.

V.

227

DEVELOPMENT OF ACCELERATOR FACILITIESStatus report on RIKEN ECR ion source operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

229

Production of high intensity 7 Li3+ ion beam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

231

Conceptual design of a 28 GHz superconducting ECR ion source . . . . . . . . . . . . . . . . . . . . . .

233

Improvement for stable operation of ﬂattop acceleration system of AVF cyclotron . . . . .

235

Study of new ﬂat-top resonator for RRC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

237

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

239

Longitudinal proﬁle monitor using plastic scintillator for RARF . . . . . . . . . . . . . . . . . . . . . . .

241

Beam current measurement using HTS-SQUID monitor for RRC . . . . . . . . . . . . . . . . . . . . . .

243

Automatic sample changer for biological samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

245

Design of rebuncher between RRC and fRC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

246

Magnetic ﬁeld measurements of RIKEN fRC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

248

Construction of the rf resonators for the fRC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

250

First cool down and excitation test of superconducting sector magnets for SRC
magnets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

251

First excitation of the SRC superconducting sector magnets . . . . . . . . . . . . . . . . . . . . . . . . . . .

252

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

254

Power supplies for magnets in RARF/RIBF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

255

Status of beam transport line from SRC to BigRIPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

257

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

259

Design of rf-linacs of new injector to RIKEN Ring Cyclotron . . . . . . . . . . . . . . . . . . . . . . . . . .

261

New 18 GHz ECR ion source for new injector system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

263

Design studies on quadrupole magnets of new injector to RRC . . . . . . . . . . . . . . . . . . . . . . . .

264

Compact design of damped cavity using SiC HOM absorbers . . . . . . . . . . . . . . . . . . . . . . . . . .

266

Highly charged ion generation using Nd-glass laser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

268

Carbon beam using DPIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

269

RADIATION MONITORING

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

271

VI.

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

273

VII.

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

283

VIII.

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

284

IX.

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

297

X.

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

299

XI.

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

306

AUTHOR INDEX

Frontispiece

Progress in RIBF Accelerators
A Universal slow RI-beam facility (SLOWRI): Development and ﬁrst results

Progress in RIBF Accelerators

Fig. 1. Bird’s-eye view of RIBF (RI-Beam Factory) and RARF (RIKEN Accelerator Research Facility) buildings. The construction of the RIBF building was completed in May,
2005. The arrows indicate the positions of the accelerators (RILAC, AVF, RRC, fRC, IRC, and SRC) and the Big-RIPS.

A universal slow RI-beam facility (SLOWRI)
Development and first results (pp. 41, 157)
The prototype SLOWRI facility
A Universal slow radioactive ion beam facility (SLOWRI) is planned as one of the principal facilities
of RIBF. A prototype setup for SLOWRI which is based on the rf ion guide technique has been tested
at the projectile fragment separator RIPS obtaining an overall eﬃciency of ≈5% for a ≈100A Mev 8 Li
ion beam. Laser spectroscopy of radioactive Be isotopes has also been performed.

Fig. 1. High energy radioactive Be isotope beam from RIPS are decelerated and cooled in the gas catcher cell. The
thermalized ions are accumulated and extracted into vacuum by combined dc and rf electric ﬁelds. The extracted slow
ions are transported to an ion trap via a rf sixpole ion beam guide (SPIG) and a quadrupole mass ﬁlter.

Fig. 2. The cylindrical dc electrode tube viewed from the bottom of
the gas cell.
Fig. 3., 4. The rf carpet electrode assembly and its central part.
Rf voltages are applied to alternate ring electrodes to form an ionbarrier ﬁeld on the carpet which keeps the ions away from the surface and a dc ﬁeld which due to diﬀerent dc oﬀset voltages on theelectrodes pushes the ions towards the exit nozzle at the center.

Fig. 5. The SPIG device located right behind the nozzle of the rf
carpet which moves the ions through diﬀerential pumping sections.

Laser Spectroscopy of 7 Be+ and 10 Be+ ions trapped in an on-line ion trap
The first physics experiment at the prototype SLOWRI was atomic spectroscopy of trapped Be isotopes with the goal of measuring the isotope shifts and hyperfine structures. In the year 2005, 10 Be+
and 7 Be+ ions were trapped and their optical transition wavelengths were determined, for the first time,with an accuracy of 3 × 10−8 .

Fig. 6. The resonant frequency of buﬀer gas cooled
7
Be+ ions in an ion trap was determined to957,347.36(4) GHz (preliminary). The absolute frequency was calibrated using a 250.7 MHz reference cavity (blue signal) and the saturation absorption of iodine
molecules (green line).

Fig.7. The linear rf ion trap used for laser spectroscopy.
The trap electrodes are mounted on a cryogenic coolinghead. Heat shieldings of the ﬁrst stage and parts of thesecond stage were removed in the photograph. The
hyperbolic quadrupole electrodes are segmented into
three sections to form an axial trapping ﬁeld.

RIKEN Accel. Prog. Rep. 39 (2006)

I. PREFACE

This issue of RIKEN Accelerator Progress Reportreports on progress of accelerator-based research activities in RIKEN Accelerator Research Facility (RARF)
up to October 2005. The research programs involve avariety of fields such as experimental and theoretical
nuclear physics, nuclear chemistry, radiation biology,
atomic physics, condensed matter physics, plant mutation, material characterization, application to spacescience, 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 andCenters in RIKEN.
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 (AVF)
cyclotron. Heavy-ion beams of a variety of elementswith energies ranging from a few A MeV to 135A MeV
are provided. Vector and tensor polarized deuterons
are also available. The three accelerators have beenused 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 accelerate heavier ions. An energy booster called CSM (Charge State
Multiplier) installed in collaboration with CNS, theUniversity of Tokyo, is used to raise the maximum
beam energy from the RILAC. This enabled to deliver high-intensity beams of intermediate mass elements 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. Two thirdsof 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 major part of the nuclear physics research was performed
with fast RI (Radioactive Isotope) beams provided by
the fragment separator RIPS. The AVF beam time
was used also for fields other than nuclear physics.
The RI Beam Factory (RIBF) project is to provide
wider variety of RI beams with higher intensities. Its
first stage includes construction of three cyclotrons,
fRC, IRC and SRC, which accelerates ions up to uranium to 350 A MeV, and a large-acceptance superconducting two-stage in-flight RI-beam separator called

BigRIPS. Commissioning will be in the year 2006.
A highlight of the RIBF construction this year is thecompletion of the superconducting sector magnets of
the SRC. Exciting the magnets with the designed
maximum-current has been achieved.
Many international collaborations are performed.
Among them are two large-size collaboration programs using overseas accelerator facilities: one is themuon 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 BNL, the RHIC spin project
achieved the first mile stone by observing the neutralpion production asymmetry with use of 3.8/pb of thedata taken from January to June of 2005. The dataof polarized proton collisions were transferred online to
Wako to be analyzed in the PHENIX Computer Centerin Japan, which is a part of RIKEN Super Combined
Cluster. Although the results are still preliminary, themodel of large gluon polarization is seemingly denied.
We have collaborated with the CNS for improving the
AVF cyclotron, and operating a CNS-built ECR ionsource and the low-energy RI beam separator (CRIB)
to use the low-energy beam from the AVF. A Wien
filter system attached to the CRIB improved the purity of secondary beams. The CNS installed a particle
analyzer for high resolution studies with the beams
from the AVF. The resolution of 80 keV (FWHM) was
achieved for the 28 Si(α,6 He)26 Si reaction.
Highlights of the year for the research at the accelerator complex of RARF are as follows. (1) The
second event indicating the production of the isotope 278 113 has been observed. (2) In-beam γ- andparticle-spectroscopy has been performed for various
proton- or neutron-rich nuclei, such as 6 He, 14 Be, 19 C,
20,27,28
Ne, 30,31 Na, 33,34 Mg, 34 Si and 60,62 Cr excitedby Coulomb excitation, proton- and α-inelastic scattering, neutron removal reactions, and nucleon transfer reactions. Many new levels have been identified,and measured transition strengths have revealed newfeature of nuclear structure. (3) Reactions involved instellar burning processes have been studied either indirectly by the Coulomb dissociation method or directlywith the low-energy RI beams from the CRIB. The
8Li(α,γ)11 B reaction was studied down to the Gamow
energy of around 0.5 MeV by using low energy 8 Li
beams. (4) The nuclear moment study in the neutronrich sd-shell region has been continued. In this year
the electric quadrupole moment of 32 Al has been de-1

termined. (5) Coulomb dissociation of the hallo nuclei
11
Li has been studied in detail. Low-energy behavior of the dipole strength function in 11 Li was established. (6) A pilot device for a slow RI-beam facility(SLOWRI) using an rf ion guide has enabled laser spectroscopy of 10 Be+ ions in an on-line trap for the firsttime. (7) Importance of indirect action of heavy-ion irradiation in killing V79 cells was identified at the very
high LET of 2106 KeV/µm. Other related research
activities are: Three nucleon system with strangenessS = −1 has been found and named as S0 (3115) as a
candidate of deeply bound kaonic system, K− pnn withthe binding energy about 200 MeV. An electron plasma
in a quadrupole magnetic field has been compressed forthe first time, which provides a unique scheme to synthesize a well-collimated spin-polarized antihydrogen
beam for the CPT symmetry test.
Construction of the RIBF has been going well. The
sector magnets and rf resonators for the fRC have beenassembled at the factory. The magnetic spectrometer
SMART has been decommissioned to use its site for
installing the fRC. The power tests of the rf systems
for the IRC are being carried out. Assembling of thesuperconducting sector magnets for the SRC has completed in summer. As mentioned earlier, we succeededin cooling-down and exciting the magnets at 3.75 Twith the maximum currents of 5,000 A and 3,000 A forthe main and trim coils, respectively. The R&D’s on
the production of uranium ions, a candidate of theions used for the first beam, have been carried out.
At present 16+ ions with more than 2 particle-µA are
extracted from the 18 GHz ECR source.
The construction of the RI-beam separator BigRIPS
and the follwing RI-beam delivery line is in progress
for their completion in early 2007. The magnets of
the BigRIPS are installed, and the superconducting
quadrupoles in the first stage have been cooled down
to test the cryogenic plant. Beam line components suchas focal plane chambers, high-power production target
and high-power beam dump have also been fabricated.

2

The RI-beam delivery line works as a spectrometer forparticled emitted at around zero degree from secondary
reactions. The magnets for the beam line are underfabrication in the same design as those of BigRIPS.
For experimental installation of RIBF, various research and developments are being performed. The
feasibility studies of a novel experimental techniquefor e-RI scattering, SCRIT (Self-Confining Radioactive Ion Target), are underway at the electron storage ring KSR of Kyoto University. Trapping of externally injected ions on the electron beam has been confirmed. Conceptual design of an isochronous ring formass measurements of short-lived and rarely-produced
nuclei is in progress. Elements of the heavy-ion synclotron TARNII has been transferred to RIKEN from
KEK. They will be used for the injection line connecting the BigRIPS and the ring. Detector developments
for a large acceptance spectrometer (SAMURAI) haveprogressed together with the spectrometer design. Design of a high-resolution spectrometer (SHARAQ) and
its dispersion-matched beam line has started. For
creation of highly polarized RI beams using primarybeams from IRC delivered to the RIPS, developmentsof a new system using the atomic beam method areunderway.
This year, the organization structure for theaccelerator-based research has been changed. The former Cyclotron Center, the Experimental Equipment
Sub-Group of the Accelerator-based Research Groupand RIBF Project Group have been unified, and a
new organization, “Accelerator Research Program” inthe Frontier Research System, has been established.
Together with related laboratories in the Discovery
Research Institute, a new Center covering the entire
accelerator-based research activities will be created in
the year 2006.

T. Motobayashi
Chief Scientist
Heavy Ion Nuclear Physics Laboratory

RIKEN Accel. Prog. Rep. 39 (2006)

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 the RILAC operation from January 1 through December 31, 2005. We reduced planned maintenance,and carried out experiments in RILAC in August 2005.
Therefore, compared with that one year ago, the operation time of RILAC increased by approximately
24%. The percentage of beam service time used by
the RIKEN Ring Cyclotron (RRC) was approximately
35% of the total RILAC beam service time. 4 He, 40 Ar,
58
Fe, 58 Ni, 70 Zn, and 131 Xe ions accelerated by RILAC
were injected into RRC.
Table 2 shows a summary of the beam service timeof the RILAC standalone allotted to the search for theheaviest elements, and to the study of radiation chemistry, accelerator mass spectrometry, and instrumentation.
Research experiments on the heaviest elements havebeen carried out with a gas-ﬁlled recoil isotope separator (GARIS) at the e3 beam line of RILAC since 2002.
This year, the experiments were carried out for 4 daysin January, 31 days from March through April, 3 daysin May, 21 days in August, 46 days from September
through October, and 23 days from November throughTable 1. Statistics for RILAC operation from January 1
through December 31, 2005.

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 2671 hours. As aresult, a convincing candidate event for the isotope of
the 113th element was observed for the second time on
April 2, 2005. In 2006, the experiment will be carriedout intensively at RILAC.
Table 3 shows the statistics for the operation time onwhich RILAC ion beams were delivered using the RFQ
linac with an 18 GHz ECR ion source (18G-ECRIS)
and a superconducting ECR ion source (SC-ECRIS).
The percentages of the operation time used by 18GECRIS and SC-ECRIS were approximately 80% and
20% of the total operation time, respectively. The ion
beams of 7 elements were used in the various experiments and beam acceleration tests.
For the RIBF project, the production of uranium
ions using the 18G-ECRIS began at an ion source roomof RILAC on October 31, 2005. We tested the production of uranium ions using the slow supply of UF6 gas
from an airtight container owing to vapor pressure atroom temperature. Uranium ion beams, such U21+ of
13 eµA intensity at an rf power of 400 W, were obtained
for the ﬁrst time in Japan. Its acceleration test withRILAC and RRC will start in spring 2006. We alreadyreceived oﬃcial licenses of the uranium handling andacceleration in April 2004 and January 2005, respectively.
We experienced the following machine problems during this reporting period.
(1) Part of the chamber wall (6 mm-thick stainlesssteel) of the 90◦ bending magnet (DMe1) had a

Table 3. Operation statistics for RILAC ion beams delivered using RFQ linac with two ion sources (18G-ECRIS
and SC-ECRIS). The operation times using SC-ECRIS
are in parentheses.
Table 2. Beam service time of RILAC standalone allocatedto diﬀerent research groups.

∗

SHI Accelerator Service, Ltd.

3

vacuum leak caused by the heat of the converged
ion beam that hit it. The leaky part was soldered. In addition, a vacuum chamber of DMe1
was newly designed and manufactured. The internal surface of the new chamber was fortiﬁed
with 1 mm-thick tantalum plates. One week ofscheduled beam time was cancelled for the repair.
(2) A new water pump of the deionized water circuit for RILAC had a terminal breakdown again.
This time, a heat exchanger of the same system
had a water leak at about the same time. Two

4weeks of scheduled beam time was cancelled forsome repairs.
(3) The ﬁnal vacuum tubes of the No. 2 and 3 ﬁnal
rf ampliﬁers have been replaced with new ones,
because they were worn out after many years ofoperation. A ﬁnal vacuum tube of the RFQ ﬁnal
rf ampliﬁer also had a problem and was replacedwith a new one.
(4) In the No. 5 cavity, the rf contact ﬁngers of theshorting plate melted due to excessive rf current. Three weeks of scheduled beam time wascancelled for the repair.

RIKEN Accel. Prog. Rep. 39 (2006)

RRC operation
M. Kase, N. Inabe, E. Ikezawa, T. Kageyama, N. Fukunishi, T. Nakagawa, O. Kamigaito, H. Ryuto, H. Okuno,
N. Sakamoto, M. Kidera, M. Wakasugi, M. Kobayashi-Komiyama, Y. Higurashi, M. Nagase, S. Kohara,
M. Fujimaki, A. Yoneda, S. Yokouchi, Y. Ohshiro,∗1 N. Tsukiori,∗2 R. Ohta,∗2 Y. Kotaka,∗2 K. Kobayashi,∗2
M. Nishida,∗2 K. Masuda,∗2 S. Fukuzawa,∗2 T. Nakamura,∗2 A. Goto, and Y. Yano
Table 1 shows the statistics of the RIKEN Ring Cyclotron (RRC) operation from Jan. to Dec. 2005. In
spite of a fund limitations for electric power in the ﬁscal year 2004, the RARF accelerators were operated
for 435 hours from January to March 2005. The total operation hours per year, which had decreased by
15% in 2004, was recovered to the level of 2003. Unscheduled shutdown took place frequently during theﬁrst half of 2005 due to machine problems and power
limitations. Table 2 shows the beam service time foreach beam course ranging from rooms E1 to E6 of the
Nishina Memorial Bldg.
Room E1 has been used for many purposes since1987 when the Riken Accelerator Research Facility(RARF) started. In 2005, simulation tests of a beam
dump in the Big-RIPS were performed at E1b using
a 63 MeV/nucleon 40 Ar beam with a power of approximately 2 kW. At the beginning of next year, all the
beam lines in room E1 will be removed and converted
into the new beam transport line of the RIBF. The useof the E1 beam lines for general purposes was termiTable 1. Operation statistice of RRC in 2005.

nated at the end of 2005.
The ﬁrst experiment was performed using a particle
analyzer (PA), which was installed at the E2a beamcourse in room E2 by CNS (the Center of Nuclear
Study, the Univ. of Tokyo) in 2001. The beam courseof E2b was used in heavy-ion channeling experiments
using a parallel beam of 92 MeV/nucleon 56 Fe.
Two long-term nuclear physics experiments (morethan ten days) were carried out from April to Junewith the spectrograph SMART in room E4 using
a 135 MeV/nucleon polarized deuteron beam. Afterthese experiments, the use of the SMART was stopped.
Subdivision of the SMART begun in July and someparts including the large dipole magnet (PD1) weretransported to the RIBF experiment building for future use.
In roon E5, biology experiments have been constantly carried out since 1989. These experiments
range in many ﬁelds such as radiation biology, mutation breeding, plant physiology, and cell biology. Recently a new target system with an automatic targetexchanging mechanism was installed. The successive
irradiations of many targets have become more eﬃcient. Experiment has been reduced on average asshown in Table 2.
Approximately 62% of the total beam time wasdevoted to experiments using secondary beams (RI
beams) produced at the RIPS by projectile fragmentations. In particular, RIPS experiments using a
63 MeV/u 40 Ar beam were carried out with priority
this year. Two long-term continuous operations of the
63 MeV/u 40 Ar beam were performed from February
to April and from October to November. The operation of RILAC-CSM-RRC continuously supplied theTable 2. RRC beam time for each beam course in 2005.

∗1∗2

Center of Nuclear Science, University of Tokyo
Sumiju Accelerator Service Ltd.

5

beam for seven RIPS experiments.
Unscheduled shutdown occurred repeatedly in theﬁrst half of 2005. In February, while an annual inspection of the cogeneration system (CGS) was underway,
the RRC had to stop due to shortage of electric power
caused by the large power consumption for heating asa result of the very cold weather. Problems with concerning the rf ampliﬁers for the RRC cavities occurred
frequently. A spark discharge around the ﬁnal-stage
electrotube damaged electronics parts. After the optimum set of parameters was carefully determined, theabove troubles became less frequent.
During operation with a high-intensity beam, a leakoccurred in the vacuum chamber inside the analysing
magnet located just after a charge stripper, probably
when a stripper foil was broken. A septum of electrostatic deﬂection channel (EDC) in the RRC extraction
system was also damaged by beam irradiation due to a
mistake in operation. A beam interlock system was introduced in the summer to prevent accelerator devices
from receiving these damages. It functions by stoppinga beam immediately when an abnormal beam current

6

is detected.
After the SMART was subdivided in June, the construction of the fRC (ﬁxed-frequency ring cyclotron)
started in August and assembly ﬁnished in December. After wiring and piping, the fRC will be readyin March 2006. The construction of beam transportlines around fRC will start in March 2006 and ﬁnish
three months later. During this period, the RRC beamservice will not be available.
The beam commissioning of the RIBF will start in2006. As the ﬁrst step, a beam test of fRC will be carried out in June. The beam commissioning including
IRC and SRC will start in autumn of 2006. The RRC
beam service in 2006 will be interrupted considerably.
Estimated beam service time is 30% of that in 2005.
The operation time of the RILAC-RRC was very
limited because most of the available beam time of
RILAC was devoted to the experiment search for Z =113 elements. Some users, who had been using thebeams from the RILAC-RRC, were requested to use
the beams from AVF-RRC instead, if possible.

RIKEN Accel. Prog. Rep. 39 (2006)

AVF operation
T. Kageyama, Y. Ohshiro,∗1 M. Kase, N. Inabe, N. Fukunishi, T. Nakagawa, O. Kamigaito, H. Ryuto,
H. Okuno, N. Sakamoto, M. Kidera, M. Wakasugi, M. Kobayashi-Komiyama, Y. Higurashi, M. Nagase,
S. Kohara, A. Yoneda, S. Yokouchi, N. Tsukiori,∗2 R. Ohta,∗2 Y. Kotaka,∗2 K. Kobayashi,∗2 M. Nishida,∗2
K. Masuda,∗2 S. Fukuzawa,∗2 T. Nakamura,∗2 A. Goto, and Y. Yano
Table 1 shows the statistics of the AVF cyclotron(AVF) operation from January to December 2005. Approximately 80% of AVF operation time was spent injecting the beam into the RRC in 2005. This percentage is expected to decrease markedly after the RIBF
commissioning starts in the following years and, as aresult, the standalone use of AVF will take priority.
The three types of ion sources shown in Fig. 1 havebeen producing various ion beams since 2003. Table 2
shows a list of all the beams accelerated with AVF in
2005. Table 3 shows the operation time for each ion
source.
In the case of ions heavier than Ar, the 10 GHz ECRion source is mainly used. For lighter ions, both the
10 GHz ECR and Hyper-ECR ion source are used alternatively. The polarized ion source (PIS) was used
continuously in April and June 2005 to supply a polarized deuteron beam to the ﬁnal SMART experiments.
Since then, the PIS has not been used for a long duration.
In the standalone use, the various beams were delivered either to the CRIB in the E7 room or the beamcourse of C03 in the AVF accelerator room. At theTable 2. Ion species and operation times.

Table 3. Operation times of ion sources.

Table 1. Operation statistics of AVF in 2005.

Fig. 1. Overview of AVF and its injection beam lines andextraction beam lines.
∗1∗2

Center of Nuclear Science, the University of Tokyo
Sumiju Accelerator Service Ltd.

CRIB, eleven nuclear physics experiments were carried out using low-energy secondary beams. The Center of Nuclear Study, The University of Tokyo (CNS),
has promoted these CRIB experiments in collaboration with RIKEN. At C03, many types of radioisotope
have been produced using mainly proton beams for the
purpose of radiochemistry.
An 8.6 MeV/u 7 Li3+ beam was successfully extracted for the ﬁrst time from the AVF in June 2005
with an intensity of 400 pnA, which was suﬃciently
strong for the CRIB experiment. A melting pot withmetallic lithium was inserted into the plasma of theHyper ECR ion source. It worked well for more than
three days.
The upgrade of the AVF has been in progress incooperation with CNS. The ﬂattop acceleration system was added to the AVF cavities in 2002. A highpower operation with the ﬂattop system was restricted
due to the damage of a ceramic insulation part of therf ampliﬁer. The improvement of the ceramic part isnow underway. The power supplies for the sector magnets were improved to increase the maximum energyof the light ion beam at the beginning of 2005. The
maximum current of the main coil was increased from7

1100 A to 1200 A. The two sets of power supplies forthe trim coils were also improved. As a result, the Kvalue of the AVF increased from 70 to 78 MeV. The
maximum energy of 15 N5+ beam was increased beyond
9 MeV/nucleon, extending the availability of RI beams
by the CRIB in E7. Acceleration tests have not been
performed yet, because of the lack of both input electric power and a suﬃcient capacity of the water coolingsystem.
According to the agreement between RIKEN and
CNS, the AVF beam should be used in regular-course
experiment for students of the Physics Department of
the University of Tokyo starting 2002. Four sets of
one-day experiments were performed from September
to December in 2005. Eight students participated ineach experiment on elastic scattering or gamma spec-8

troscopy using a 6 MeV/u alpha beam from the AVF.
The total number of students has increased by 25%
compared with that in the ﬁrst year of 2002.
Problems with the AVF occurred mainly in March
2005. The position control mechanism of the gradientcollector in the extraction system of the AVF broke
down. A water leak into the vacuum chamber occurred at the septum electrode of the deﬂector. A
high-voltage cable, which sustains the power feed into
one of the rf ampliﬁer, was damaged. A radial probe
had diﬃculty in performing smooth operation owing
to the failure of mechanical coupling in June. These
problems caused a total of 141 hr of unscheduled shutdown for the AVF-RRC beam time and a total of 80
hr for the AVF standalone beam time.

RIKEN Accel. Prog. Rep. 39 (2006)

Operation of tandem accelerator
T. Kobayashi and K. Ogiwara
The 1.7 MV tandem accelerator (Pelletron) was operated for a total of 125 days for experiments during
the annual report period from Nov. 1, 2004 to Oct. 31,
2005. The number of operation days increased by approximately 30% that of the previous year due to theparticipation of a new experimental group for semiconductor materials. A total of 32 days was spent formachine inspection, troubleshooting and beam testing
including shutdown and recovery for electric power failure. The details of the problems during this period andthe days required for repair are as follows.
(1) Leakage of SF6 (4 days)
The isolation gas SF6 leaked from the high-pressuretank in November. The leakage occurred at the sealof the corona-detection electrode. The electrode wasexchanged and SF6 was added from a gas cylinder.
(2) Wear of carbon sheaves (3 days)
There are four sheaves for charge transfer in the HVgenerator. One of them wore out in January and the
HV became unstable. The wear amount of carbon depends on the tension of the charge transfer chain andthe lifetime is approximately 3–5 years.
(3) Damage of charge transfer chain (3 days)
The charge transfer chain consists of aluminum pellets and nylon joints. In January, one of the joints
was broken. The cause of this accident is not clear.
However, no abnormality was found in other joints bycareful investigation.
(4) Contamination of quartz tube in He ion source (8days)
This trouble occurred frequently during this period and was due to metallic Rb vapor used for the

production of He− ions. The productivity of He ionsmarkedly drops with contamination. Recently, we have
prevented the backward diﬀusion of Rb vapor by ﬂowing He gas continuously during and after operation.
By this method, contamination has been suppressed.
The accelerated ion species during this period were
H+ , He+ and B+ with energies from 1.6 to 2.5 MeV
summarized in Table 1.
Experimental studies on the following subjects were
performed, and are still in progress.
(1) Nuclear reaction analysis (NRA) using 1 H(11 B,α)2αreaction (67 days)(a) The state of hydrogen in Nb-based and Ta-based
alloys, and V as investigated by the channeling method(b) Eﬀect of irradiation on the state of hydrogen inmetals(2) Particle-induced X-ray emission (PIXE) (18 days)(a) Development and application of highly sensitive
high-resolution in-air PIXE system for chemical state
analysis(b) Trace element analysis of biological and environmental samples using energy dispersive X-ray spectrometry(3) Analysis using elastic scattering (40 days)(a) Rutherford backscattering spectrometry (RBS)
analysis of polymers, carbon materials, GaN, AlGaNand ZnO.
(b) Elastic recoil detection (ERD) analysis of
diamond-like carbon (DLC) thin ﬁlms and ionimplanted polymers for determining hydrogen content.
The total time in days, which was spent for eachexperiment, is shown in parentheses.

Table 1. Beam conditions and analysis techniques of Pelletron accelerator.
Ion
1

H+

4

+

He

11

B+

Energy [MeV]Beam current [nA]

Analysis

Operation time [days]

1.6–2.5

30–50

PIXE

18

2.0–2.3

5–20

RBS, ERDA40

2.0

1.0–1.5

NRA

67

9

RIKEN Accel. Prog. Rep. 39 (2006)16

C inelastic scattering studied with the microscopic
coupled-channels method†
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 have been theoretically suggested1,2) by the method of antisymmetrizedmolecular dynamics (AMD): The proton density has
an oblate deformation, whereas the neutron density
has a prolate deformation, and the symmetry axis ofproton distribution is perpendicular to that of neutron
distribution in 10 C and 16 C. According to Ref. 2, the16
C is a rotational excited state, and the ro2+
1 state oftational axis is perpendicular to the neutron symmetryaxis. In this excitation mechanism, the proton transi+tion strength is reduced, and the 0+
1 → 21 transition
is dominated by the neutron excitation.
To search for the possible diﬀerence between proton and neutron contributions to the excitation of
16
C, an inelastic scattering experithe 2+
1 state in16
208
Pb target was performed3) applyment of C on
ing the Coulomb-nuclear interference method. The
analysis was carried out using the deformed potential model, and the proton and neutron transition matrix elements, Mp and Mn , were extracted. However,the phenomenological analysis done in Ref. 3 contains
some assumptions, and hence, it seems inappropriate
to compare the Mp and Mn evaluated in Ref. 3 withthose calculated theoretically.
To test the 16 C internal wave function, we should
directly link the cross section with the wave function
by calculating the diﬀerential cross sections of the inelastic scattering of 16 C on 208 Pb target by the microscopic coupled-channels (MCC) method, and compare
the calculated result with the experimental reaction
data measured in Ref. 3.
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.4)
Here, we use the AMD wave function to calculate(a)ρik (ra ). In Ref. 2, two versions of the 16 C internal†∗1∗2

wave function are obtained, changing the strength of
the spin-orbit force, (i) uls = 900 MeV and (ii) uls =1500 MeV. In addition, we also use the AMD wave
function for which the strength of the spin-orbit force
is set to (iii) uls = 2000 MeV so as to reduce theB(E2), close to the experimental value. The B(E2)values obtained with these three wave functions are
4+
2
B(E2; 2+
1 → 01 ) = 1.9, 1.4, and 0.93 e fm , respec208
Pb nucleus istively. The density distribution of theobtained by unfolding the measured charge form factor with the realistic proton charge form factor and
it is assumed that the shape of the neutron density
is the same as that of the proton density, namely
ρn (r) = (N/Z)ρp (r).
The results are shown in Fig. 1. It is found that
the MCC calculations with the AMD wave functions(i) and (ii) reproduce the experimental data fairly wellwithout introducing any normalization factor for the
calculated diﬀerential cross sections, whereas the result with the wave function of case (iii) severely underestimates the measured diﬀerential cross sections.
We conclude that the AMD wave function (i) predicts the neutron excitation strength of 16 C reasonably
well, and that the MCC calculation is a useful tool tolink the inelastic scattering data with the internal wave
functions obtained theoretically.

Condensed from the article in Phys. Rev. C 71, 054602(2005)
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Department of Physics, Osaka City University

Fig. 1. Results of MCC calculations with AMD wave functions (i), (ii) and (iii) shown by solid, dotted and dashedcurves, respectively.

References
1) Y. Kanada-En’yo and H. Horiuchi: Prog. Theor. Phys.
Suppl. No. 142, 205 (2001).
2) Y. Kanada-En’yo: Phys. Rev. C 71, 014310 (2005).
3) Z. Elekes et al.: Phys. Lett. B 586, 34 (2004).
4) M. El-Azab Farid and G. R. Satchler: Nucl. Phys. A
438, 525 (1985).

11

RIKEN Accel. Prog. Rep. 39 (2006)

Coulomb breakup eﬀects on elastic cross section of 6 He+209 Bi
scattering near Coulomb barrier energies
T. Matsumoto, T. Egami,∗1 K. Ogata,∗1 Y. Iseri,∗2 M. Kamimura, and M. Yahiro∗1[Nuclear reaction, unstable nuclei]
Recently, Keeley et al.1) have analyzed 6 He+209 Bi
scattering at 19 and 22.5 MeV near the Coulomb barrier energy2,3) by the continuum-discretized coupledchannels method (CDCC)4) that is a fully quantummechanical method for describing the scattering of athree-body system. In the analysis, the 6 He+209 Bi system was assumed to be the 2 n+4 He+209 Bi three-bodysystem, that is, the neutron pair in 6 He was treatedas a single particle, di-neutron (2 n). Their calculation,
however, did not reproduce the experimental data ofthe elastic and total reaction cross sections. This indicates that the 6 He+209 Bi scattering cannot be described by the three-body model. Since 6 He is wellknown as a two-neutron halo nucleus, its structure
should be described by the n+n+4 He three-body system rather than the 2 n+4 He two-body one. Thus, itis necessary to analyze the 6 He+209 Bi scattering using
the n+n+4 He+209 Bi four-body model.
In our previous work,5) we proposed four-body
CDCC that is an extension of CDCC and describes
four-body breakup processes. In four-body CDCC,
three-body breakup continuum of the projectile is discretized by diagonalizing the internal Hamiltonian in aspace spanned by the Gaussian basis functions. Thusfar, the Gaussian basis function has been used withsuccess for solving bound-state problems of few-bodysystems. The approach is called the Gaussian expansion method (GEM).6) Four-body CDCC was successfully applied to 6 He+12 C scattering at 18 and229.8 MeV in which only nuclear breakup was significant.7) The elastic and breakup cross sections calculated with four-body CDCC are found to converge as
the number of Gaussian basis functions is increased.
This indicates that the set of discretized continuum
states obtained with GEM forms a complete set withgood accuracy in a finite region of space that is important for the four-body reaction process concerned.
Furthermore, Egami et al.8) showed the applicability of
CDCC with GEM to Coulomb breakup processes for
8
B+58 Ni scattering at 25.8 MeV. Thus, it is expectedthat four-body CDCC with GEM accurately describes
four-body breakup reactions near the Coulomb barrierenergy.
In this work, we analyze 6 He+209 Bi scattering at
19 and 22.5 MeV by four-body CDCC in which thescattering is described by the n+n+4 He+209 Bi model.
This is the first application of four-body CDCC to low∗1∗2

12Department of Physics, Kyushu University
Department of Physics, Chiba-Keizai College

energy scattering in which both nuclear and Coulomb
breakup processes are significant.
It is found that four-body CDCC reproduces the angular distribution of the measured elastic cross sections as shown in Fig. 1. Also the calculated total
reaction cross sections are in good agreement withthe experimental data. Meanwhile the CDCC calculation based on the di-neutron model of 6 He, i.e., the2n+4 He+209 Bi three-body model, does not reproduce
the data. We thus conclude that the n+n+4 He+209 Bi
four-body reaction model is necessary to accurately describe the 6 He+209 Bi scattering. Four-body CDCC isindispensable to analyze low-energy 6 He scattering inwhich both nuclear and Coulomb breakup processes
are significant.

Fig. 1. Angular distribution of the elastic diﬀerential crosssection as a ratio to the Rutherford cross section for
6
He+209 Bi scattering at 19 and 22.5 MeV.

References
1) N. Keeley et al.: Phys. Rev. C 68, 054601 (2003).
2) E. F. Aguilera et al.: Phys. Rev. Lett. 84, 5058 (2000).
3) E. F. Aguilera et al.: Phys. Rev. C 63, 061603(R)(2001).
4) M. Kamimura et al.: Prog. Theor. Phys. Suppl. 89, 1(1986).
5) T. Matsumoto et al.: Phys. Rev. C 70, 061601 (2004).
6) For a review, E. Hiyama et al.: Prog. Part. Nucl. Phys.
51, 223 (2003).
7) T. Matsumoto et al.: Phys. Rev. C 68, 064607 (2003).
8) T. Egami et al.: Phys. Rev. C 70, 047604 (2004).

RIKEN Accel. Prog. Rep. 39 (2006)

Reaction cross section described by a black sphereapproximation of nuclei†
A. Kohama, K. Iida, and K. Oyamatsu∗[Nuclear reaction, reaction cross section, nuclear radius, unstable nuclei]
The size of atomic nuclei is considered to be welldeduced from empirical data for the proton-nucleus
elastic diﬀerential cross section, dσel /dΩ, and the total reaction cross section, σR ≡ σT − σel , where σTis the total cross section.1) Thus far, the analysis that
respects both data in deducing the nuclear size has
not been completed in particular for proton incident
energies, Tp , higher than 800 MeV.
In this work, we identify a length scale that simultaneously accounts for the observed proton-nucleus reaction cross section and diﬀraction peak in the proton
elastic diﬀerential cross section. This scale is the nuclear radius, a, deduced from proton elastic scattering
data of incident energies higher than ∼800 MeV, byassuming that the target nucleus is a “black” sphere.2)
We determine a in such a way that the c.m. scattering angle [θc.m. ≡ 2 sin−1 (q/2p)] of the ﬁrst maximum
for the Fraunhofer diﬀraction agrees with that measured by proton-nucleus elastic scattering, θM . Here,
we deﬁne the zeroth peak as that whose angle corresponds to θc.m. = 0. 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:(2)
rBS ≡ 3/5a.
The factor 3/5 originates from the assumption thatthe density distribution of the black sphere is uniform.
We have two signiﬁcant results, while ﬁnalizing asystematic analysis of the existing data for proton elastic scattering oﬀ stable nuclei ranging from He to Pb at
proton incident energies above ∼800 MeV. First, thevalues of rBS obtained from Eq. (2) are systematicallylarger than the root-mean-square radius rm deduced
from elaborate scattering theory for A < 50, although
they agree quite well with each other for A > 50. Thissuggests a signiﬁcant deviation of the nucleon distribution from the rectangular one for A < 50, which isconsistent with the behavior of the empirical charge
distribution.3) Second, the absorption cross section,
σBS (= πa2 ), is consistent with the empirical total reaction cross section for C, Sn, and Pb to within error†∗

bars as shown in Fig. 1. This consistency persists inthe case of the interaction cross section measured fora carbon target. We thus see the dual role of a as a
black sphere radius and as a reaction radius.
We now prepare for future possible application of theblack sphere approximation to neutron-rich unstable
nuclei expected to be produced at RIKEN and GSI.

Fig. 1. Absorption cross section, σBS (= πa2 ), of a proton
of Tp ≥ 800 MeV by a target nucleus of mass number A. For comparison, we plot the empirical data forthe proton-nucleus total reaction cross section, σR (◦),
which are listed in Ref. 4 for 9 Be, 12 C, 27 Al, Cu, Sn,
and Pb. For the latter three elements the value of σR isthe average over the isotopic abundance in a target. For
these data, we set A as the mass number of the mostabundant isotope and assign the uncertainty in A due
to the natural abundance. The dashed curve denotes(5/3)π(0.94A1/3 )2 fm2 . Inset: σBS vs σR for 12 C, Sn,
and Pb. The dotted line represents σBS = σR .

References
1) C. J. Batty, E. Friedman, H. J. Gils, and H. Rebel: Adv.
Nucl. Phys. 19, 1 (1989).
2) A. Kohama, K. Iida, and K. Oyamatsu: Phys. Rev. C
69, 064316 (2004).
3) 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.
4) W. Bauhoﬀ: At. Data Nucl. Data Tables 35, 429 (1986).

Condensed from the article in Phys. Rev. C 72, 024602(2005)
Department of Media Theories and Production, Aichi
Shukutoku University

13

RIKEN Accel. Prog. Rep. 39 (2006)

Study of oxygen isotopes by charge- and parity-projected
Hartree-Fock method
S. Sugimoto,∗1 K. Ikeda, and H. Toki∗2[Nuclear structure, tensor force, mean ﬁeld model]
Recently, we have proposed a mean-ﬁeld-type framework that treats the correlation by the tensor force by
mixing parities and charges in single-particle states.1)
We applied this method to alpha particles and foundthat the tensor correlation can be exploited. The tensor force should have eﬀects on the structure of nuclei
over the whole mass region and, therefore, it is interesting to apply our method to heavier mass nuclei. In
this paper, we report the application of our method tooxygen isotopes.
As we mentioned above, we mix parities (positive
and negative) and charge states (proton and neutron)
in a single-particle state. A Slater determinant, whichis composed of such single-particle states with mixingof parities and charges, does not have a good parity
and a good charge number. To a exploit state witha good parity and a good charge number, we performthe parity and charge projections. By considering thevariation of the projected wave function with respect
to single-particle states, we obtain a Hartree-Focklike equation, namely, the charge- and parity-projected
Hartree-Fock (CPPHF) equation. In our method (theCPPHF method), we solve the CPPHF equation selfconsistently.1)
We take the Hamiltonian in the following form,

A 

h̄2
H=
∆i + VC + V3B + VT−
2M
i=1
+ VLS + VCoul − ECM .

(1)Here, the ﬁrst term is the kinetic energy. VC , V3B , VT ,VLS , and VCoul are the potential energies from the central force, three-body force, tensor force, LS force, andCoulomb force, respectively. We subtract the energyof the center of mass motion ECM . For the central
and three-body forces, we adopt the modiﬁed Volkov
No.1 force.2) For the tensor and LS forces we adopt
the G3RS force.3) We strengthen the tensor force bymultiplying the τ1 · τ2 part in the tensor force by xT to
take into account correlations that cannot be treatedin the CPPHF method. We also multiply the attraction part of the triple-even channel in the central force

∗1
∗2

14

Department of Physics, Graduate School of Science, Kyoto
University
Research Center for Nuclear Physics, Osaka University

by the factor xTE and the three-body force by x3B toreproduce the binding energy and the charge radius of16
O.
In Table 1, the result for the sub-closed-shell oxygenisotopes is shown. In the calculation we take xT = 1.5,
xTE = 1.04, and x3B = 1.55. We also multiply the
LS force by a factor of 2. It is required to reproduce
the binding energy of 14 O and 22 O reasonably. From
the table we can see that relatively large energy gains
come from the tensor force. These are much larger
than the energy gains from the LS force. The potential
energies from the tensor force have a shell-structure
dependence, which is of the same order as that of the
LS force. This suggests that the tensor force has aneﬀect on the shell structure of the nuclei. To study theeﬀect of the tensor force on shell structure, we needto investigate single-particle structure and now we aretrying to calculate the 1-particle states like 17 O. We
hope we will show the result in the near future.
Table 1. Result for sub-closed-shell oxygen isotopes in CPPHF method. E, K, and V are the total energy, thekinetic energy including the correction for the center ofmass motion, and the potential energy, respectively. VT
and VLS are the contributions to the potential energy
from the tensor and LS forces, respectively. They are
give in MeV. Rm is the matter radius in fm.
14

O
O
22
O
24
O
28
O
16

E
−100.4−127.6−153.8−164.4−175.8

K
272.9
253.9
371.4
415.7
442.9

V
−373.4−381.6−525.3−580.1−618.7

VT
−75.3
−38.3
−40.5
−57.6
−45.1

VLS
−11.9
−1.0
−19.4
−19.7
−1.9

Rm
2.43
2.60
2.93
3.03
3.27

References
1) S. Sugimoto, K. Ikeda, and H. Toki: Nucl. Phys. A 740,
77 (2004).
2) T. Ando, K. Ikeda, and A. Tohsaki-Suzuki: Prog.
Theor. Phys. 64, 1608 (1980).
3) R. Tamagaki: Prog. Theor. Phys. 39, 91 (1968).

RIKEN Accel. Prog. Rep. 39 (2006)

Tensor correlation in neutron halo nuclei
T. Myo,∗1 K. Katō,∗2 H. Toki,∗1 and K. Ikeda[Nuclear structure, unstable nuclei, cluster model, tensor force]
The tensor force is an essential component in nuclear
force and plays an important role in the nuclear structure.1) In this report, we investigate the role of thetensor force in neutron halo nuclei 6 He and 11 Li. In
most theoretical studies of halo nuclei, the core+n+nmodel is often used, where an inert core is assumed,
such as the (0s)4 of 4 He in 6 He. In this picture, thetensor force cannot work in the core or in the coupling
between core and valence neutrons. Thus, the tensor
correlation in neutron halo nuclei has not been realized. For 11 Li, the mechanism of the lowering of the
1s orbit is still unclear. It is also of interest to examine
the eﬀect of the tensor correlation on this problem.
We consider the tensor correlation as follows. The
tensor force tends to change the parity of the single
particle orbit due to the (σ · r) operator. This is a
result of the one pion exchange potential, namely, thepion. Then, in 4 He, the 0s and 0p orbits can be coupledby the tensor force, and we extend the model space into(0s)4 + (0s)2 (0p)2 .2–5) In fact, we take up to the 2p2h
excitation of 0s + 0p + sd shells to include the tensor correlation in 4 He. We employ Akaishi’s eﬀective
N N force5) derived from the G-matrix theory. We use
the harmonic oscillator basis for a single particle orbit and determine the length parameter of each orbit
variationally. The obtained wave function has narrow
0p and 0d orbits, which represent the higher shell effect of the tensor force. Among the 2p2h components,(0p1/2 )2 (0s1/2 )−2 is well mixed, about 5%. The expectation value of the tensor force is −40.1 MeV.
We also solve the coupled 4 He+n problem with tensor correlation. Since the Pauli blocking mainly occurs
in the 1/2− state from the large 0p1/2 component in
4
He, splitting of 1/2− –3/2− can arise in 5 He. We startfrom the microscopic 4 He-n potential, KKNN,6) andmake a new 4 He-n potential including the tensor correlation with weakening of the LS part of KKNN by
about half. In the new model, the d-wave behavior is
improved, as shown in Fig. 1.4) We also solve the coupled three-body model of 6 He shown in Fig. 2, where
the Pauli-blocking eﬀect occurs in the 0+
2 state related
to the 0p1/2 orbit.
We found that the tensor correlation strongly aﬀects
the properties of the 0p1/2 orbit. This seems crucial in
the s-state problem in 11 Li. To conﬁrm this, we solve
the coupled 9 Li+n+n model for 11 Li, where we include the 2p2h excitation from 0s to 0p orbits in 9 Li.
In 11 Li, the 0p1/2 orbits in 9 Li couple to the p-wave∗1∗2

Research Center for Nuclear Physics, Osaka University
Graduate School of Science, Hokkaido University

Fig. 1. 4 He+n d-wave phase shifts with tensor correlation.

Fig. 2. 6 He spectrum with tensor correlation.

valence neutrons. This produces the Pauli-blocking effect, and the p-state energy of 11 Li is lost. The results
are shown in Table 1. We conﬁrm that the s-state mixing increases when considering the tensor correlationin comparison with the single channel case. In fact, thecontribution of the tensor force decreases by 5.6 MeV
in 11 Li in comparison with isolated 9 Li.
Table 1. Properties of 9 Li and 11 Li. P is the probability.
9

Li

11

Li

E [MeV]VT  [MeV]
P (2p2h) [%]P ((1s)2 ) [%]Rm [fm]Single
—
—
—
2.3
2.88

Couple
−39.7
−19.8
7.2
21.6
3.08

Expt.
−45.3
—
—
∼ 50

3.12 ± 0.16
3.53 ± 0.06

References
1) Y. Akaishi et al.: Int. Rev. Nucl. Phys. 4, 259 (1988).
2) T. Terasawa: Prog. Theor. Phys. 23, 87 (1960).
3) S. Sugimoto et al.: Nucl. Phys. A 740, 77 (2004).
4) T. Myo et al.: Prog. Theor. Phys. 113, 763 (2005).
5) Y. Akaishi: Nucl. Phys. A 738, 80 (2004).
6) H. Kanada et al.: Prog. Theor. Phys. 61, 1327 (1979).

15

RIKEN Accel. Prog. Rep. 39 (2006)

Three-body cluster states in 11 C and 11 B
Y. Kanada-En’yo∗[Nuclear structure, unstable nuclei, cluster]In 12 C, it is known that 3α-cluster states develop in
excited states such as the 0+
2 (7.65 MeV) state. Tohsaki
et al.1,2) proposed that 0+
2 is a dilute state which is considered to be a weakly interacting gas of 3 α particles.
There is a question whether such loosely bound multicluster states may appear in other nuclear systems.
Our aim is to study the structure of excited states of
11
C and 11 B and search for dilute cluster states composed of three weakly interacting clusters.
The present study has been motivated by the recent measurements of Gamov-Teller (GT ) transitions
11
B→11 C∗ with high energy resolutions.3) In the experiments, it has been found that GT transitions into
11
C are extremely weakthe 3/2−
3 (8.10 MeV) state ofcompared with other low-lying states. Abnormal features of 3/2−
3 have been known also in the mirror nu11
B has relatively
cleus 11 B. For example, the 3/2−
3 ofweak M 1 transitions into the lower states comparedwith strong transitions among other low-lying states.
Moreover, it is also mysterious that in shell model calculations, no theoretical state can be assigned to 3/2−
3.
These facts indicate that 3/2−
may
have
an
exotic3
structure diﬀerent from those of normal shell-modellike states, and is a candidate for the three-center cluster state.
In the present work, we apply the method of antisymmetrized molecular dynamics (AMD). We perform
energy variation after spin parity projection (VAP)
within the AMD model space, as was done in previous studies.4,5)
In Table 1, the calculated excitation energies and GTtransition strengths for the negative parity states of
11
C are shown compared with the experimental data.
The present calculations well reproduce the experimental B(GT ;11 B→11 C) values. The calculations also
agree well with the M 1 transition strengths in 11 B and
11
C. As mentioned before, the characteristic proper11
B(3/2−
ties of 11 C(3/2−
3 , 8.10 MeV) and3 , 8.65 MeV)
are small B(GT ) and B(M 1). In the present calculations, the quenching of GT and M 1 transitions for the
3/2−
3 states can be described by their exotic structure.
Namely, the 3/2−
3 states exhibit the well-developed
2α + 3 He and 2α + t clustering, and therefore, they
have a small transition overlap with the other normal
low-lying states.
By analyzing the wave function of the excitedstates, we ﬁnd that 11 C(3/2−
3 ) is a three-center cluster state with loosely bound 2α + 3 He. The features∗

16

Yukawa Institute for Theoretical Physics, Kyoto Universityof the loose binding of 11 C(3/2−
3 ) are very similar
to those of 12 C(0+2 , 7.65 MeV), which is known to
be a dilute gaslike 3α state. Therefore, we consider
11
B(3/2−
that 11 C(3/2−
3 , 8.10 MeV) and3 ,8.56 MeV)
are candidates for dilute gaslike cluster states with
2α + 3 He and 2α + t, respectively.
Another interesting result of the present work is thatthe 5/2−
2 state is described by a mixture of two components. The dominant component is the state with
the intrinsic spin excitation, and the other one contains cluster correlations in terms of the SU (3) limit
clustering. Moreover, in the present calculations, we
ﬁnd many 7 Li + α and 7 Be + α cluster states in thehigher negative parity states as well as in the positive
parity states.
It is concluded that various types of cluster states
appear in the excited states of 11 C and 11 B. A
new revelation in the present work is that 11 C(3/2−
3,
,
8.56
MeV)
are
considered
8.10 MeV) and 11 B(3/2−3
to be three-center cluster states with loosely bound2α + 3 He and 2α + t, respectively.
Table 1. Gamov-Teller transition strengths from 11 Bg.s.
to 11 C and excitation energies. The theoretical values were calculated by the AMD (VAP) method. The
adopted interaction consists of the central force of MV1(m = 0.62, b = h = 0.25), the spin-orbit force of GSRS(uI = −uII = 2800 MeV), and Coulomb force. The
experimental data are taken from Ref. 3.
Jkπ
3/2−
1
1/2−
1
5/2−
1
3/2−
2
7/2−
1
3/2−
3
5/2−
2

Ex
0.0
2.00
4.32
4.80
6.48
8.10
8.42

exp.
B(GT )
0.345(8)0.440(22)0.526(27)0.525(27)−0.005(2)0.461(23)

Ex
0.0
2.8
3.6
5.8
5.4
10.5
10.5

theor.
B(GT )
0.40
0.43
0.70
0.67
−
0.02
0.56

References
1) A. Tohsaki et al.: Phys. Rev. Lett. 87, 192501 (2001).
2) Y. Funaki et al.: Phys. Rev. C 67, 051306 (2003).
3) Y. Fujita et al.: Phys. Rev. C 70, 011306(R) (2004).
4) Y. Kanada-En’yo: Phys. Rev. Lett. 81, 5291 (1998).
5) Y. Kanada-En’yo, H. Horiuchi, and A. Doté: Phys. Rev.
C 60, 064304 (1999).

RIKEN Accel. Prog. Rep. 39 (2006)

Alpha particle condensation in 12 C
Y. Funaki, A. Tohsaki,∗1 H. Horiuchi, P. Schuck,∗2 and G. Röpke∗3[Nuclear structure, cluster model, alpha particle]
Recently, we proposed that near the nα breakup
threshold in self-conjugate 4n nuclei, there exist BoseEinstein condensed states in which self-bound α particles weakly interact like a gas and occupy the same lowest 0s state, obeying Bose statistics.1) We investigated
the structures of 12 C and 16 O using a new α-cluster
wave function of the α-cluster condensate type, and12
C (Hoyle state), observed
identiﬁed the 0+
2 state of
at 0.38 MeV above the 3α threshold, and the 0+
5 stateof 16 O, observed at 0.44 MeV below the 4α threshold,as a candidate of the 3α condensed state and a possible
candidate of the 4α condensed state, respectively.
According to the above proposal, we conducted amore detailed analysis of the excited state of 12 C observed near the 3α threshold, using a deformed alphacondensate wave function which only slightly deviatesfrom the spherical one introduced in Ref. 1. The alpha condensed wave function extended to a deformed
functional space can be written as,2)Φnα ∝ A (X i )2 kφ(αexp −2
)
.
i
Bk2
i=1

n


(1)

k=x,y,z
Here, φ(αi ) ∝ exp[−(1/2b2 ) 4j (rj(i) − X i )2 ] and4
X i = j r j(i) /4, with j(i) ≡ 4(i−1)+j, are the internal wave functions and center-of-mass coordinates of
the i-th α cluster, respectively. This wave function has
the characteristic feature that all center-of-mass motions of the constituent alpha clustersoccupy the samedeformed Gaussian orbit, exp(−2 k=x,y,z Xk2 /Bk2 ).
This feature is maintained as long as the variationalparameter Bk is a suﬃciently large value that the action of the antisymmetrizer, A, is weak and can beneglected. We impose an axial symmetric restriction,
Bx = By = Bz for simplicity in all calculations.
For the 3α cluster states of 12 C, detailed analysis was already conducted by several authors about aquarter-century ago.3) In particular, complete 3α calculation with a fully microscopic model was performedby solving the following RGM equation, φ3α |(H −E)|A{χ(s, t)φ3α } = 0, s and t being the Jacobi coordinates of the center-of-mass motion of three α clusters. The calculated 0+
2 wave function well reproduced
most of the observed experimental data, such as thebinding energy, B(E2) value, and inelastic electron
scattering form factor. We found that the 0+
2 wavefunction obtained by solving the RGM equation has a
∗1
∗2
∗3

Suzuki Corporation
Institut de Physique Nucléaire, FranceInstitut für Physik, Universität Rostock, Germany

large squared overlap value of 97% with the single condensate wave function of a 3α gaslike structure which
is projected onto J π =0+ , using Eq. (1).4) Considering
the fact that the RGM equation was solved without
any model assumption for the inter-alpha motions, thisresult gives deﬁnitive theoretical evidence that the 0+
2state can be understood to be a 3α condensed state.
3)
Besides the 0+
2 state, the former theoretical works
indicated the existence of the 2+state,
whichislo2
cated at about 3.0 MeV above the 3α threshold andhas a typical 3α cluster structure, though this state
had been unknown experimentally. However, recently,
the 2+
2 state was observed at 2.6 ± 0.3 MeV above
the 3α threshold, together with the α-decay width,
1.0 ± 0.3 MeV.5) Since this state is observed as aresonance with non small α-decay width, it shouldbe treated beyond the bound-state approximation inwhich a proper boundary condition is imposed. As
one of the proper treatments, we applied the analytic
continuation in the coupling constant (ACCC) method
to the present formalism, which enables us to calculate
the resonance energy and width.6)
The calculated binding energy and width are
2.1 MeV and 0.64 MeV, respectively, with the use of
Volkov No.1 force as the eﬀective nuclear force, and arein good agreement with the experimental values. We
found that the resonance 2+
2 wave function can be described by the single condensate wave function of the
3α gaslike structure which is projected onto J π =2+ ,using Eq. (1). By a simple analysis of the single condensate wave function with J π = 2+ , we found thatthe 2+
2 state is obtained by promoting just one α cluster out of the condensate of the 0+
2 state into a D-wave.
state
has
a structure similar toThis implies that the 2+
2
state
which
has
a
gaslikestructure comthat of the 0+2
posed of 3α clusters and exhibits the Bose-condensate
character.
References
1) A. Tohsaki, H. Horiuchi, P. Schuck, and G. Röpke:
Phys. Rev. Lett. 87, 192501 (2001).
2) Y. Funaki, H. Horiuchi, A. Tohsaki, P. Schuck, and G.
Röpke: Prog. Theor. Phys. 108, 297 (2002).
3) For example, Y. Fujiwara, H. Horiuchi, K. Ikeda, M.
Kamimura, K. Katō, Y. Suzuki, and E. Uegaki: Prog.
Theor. Phys. Suppl. No. 68, 29 (1980).
4) Y. Funaki, A. Tohsaki, H. Horiuchi, P. Schuck, and G.
Röpke: Phys. Rev. C 67, 051306 (R) (2003).
5) M. Itoh et al.: Nucl. Phys. A 738, 268 (2004).
6) Y. Funaki, H. Horiuchi, A. Tohsaki, P. Schuck, and G.
Röpke: Eur. Phys. J. A 24, 321 (2005).

17

RIKEN Accel. Prog. Rep. 39 (2006)

Molecular-orbital and di-nuclei states of 22 Ne
M. Kimura∗ and H. Horiuchi[Nuclear structure, cluster structure]
The successful description of Be isotopes by assuming a molecular-orbital structure (2α cluster core plus
covalently valence neutrons) suggests a new type ofclustering which is peculiar to neutron-rich isotopes.
It will be of importance to investigate whether themolecular-orbital structure exists not only in Be isotopes but also in heavier systems.
Ne isotopes are one of the promising candidatesof such heavier systems, since 20 Ne has a prominentα+16 O clustering in its ground state and many excited states. In this work, we have investigated thestructure of 22 Ne focusing on the α clustering by combining the theoretical framework of the deformed-basis
AMD and α+18 O(0+1 ) cluster model. By calculation,
we have obtained the ground state and many excitedstates of 22 Ne. Among the obtained states, the spectraof the excited bands which show considerable α clustering are plotted in Fig. 1, together with that of theground band.
The excited bands with the prominent α clustering are categorized into two types. The ﬁrst type isthe molecular-orbital band in which the system has
an α+16 O cluster core and two valence neutrons orbit−−
around the core. The K π =0+
2 , 01 and 1 bands belong+−π
to this type. The K =02 and 01 bands have similar
intrinsic wave functions in which two valance neutrons

occupy the orbital that is elongated along the α+16 O
clustering of the core (Fig. 2). This orbital can be decomposed into the 1s0d orbital around 16 O and the
0p orbital around α, and is considered as an analogueof the σ1/2 -molecular-orbital of Be isotopes. The mostimportant diﬀerence between the present σ-orbital andthat of the Be isotopes is the parity asymmetry of thepresent one which is due to the parity asymmetry of thecluster core. The prominent parity-asymmetry of thetotal system of the σ 2 molecular-orbital states leads tothe existence of the parity-doublet bands of K π =0+222
and 0−
Ne with almost the same intrinsic wave
1 infunction. In the K π =1− band, one of the valence neutrons occupies the σ-orbital and the other occupies theparity-symmetric orbital which has the dominant component of the 0d5/2 orbital. These three bands are built
on the states around the α+18 O threshold energy andcorrespond to the states with the prominent α reduced
widths experimentally observed in the α transfer reaction.1) Indeed the calculated and observed excitationenergies and α reduced widths show good agreement.
The second type is the di-molecule band in which
the system is divided into α and 18 O clusters. The−
K π =0+3 and 02 bands belong to this type. Their excitation energies are higher than that of the molecularorbital band and the α+18 O threshold energy. In thesebands, two valence neutrons orbit only around the 16 O.
We consider that these bands correspond to the observed α+18 O molecular resonances,2) since the calculated and observed α reduced widths show qualitative
agreement.
From the present results, we suggest the two diﬀerent kinds of α cluster structure in 22 Ne. The ﬁrst one
is the molecular-orbital structure and the second oneis the di-molecule structure.

Fig. 2. Density plot for σ-orbital (gray scaled plot) and for
α+16 O core (contour lines) of K π =0−1 band.
Fig. 1. Observed and calculated level schemes of excited
bands with α clustering and ground band.
∗

18

Yukawa Institute for Theoretical Physics, Kyoto University

References
1) W. Scholz et al.: Phys. Rev. C 6, 893 (1972).
2) V. Z. Goldberg et al.: Phys. Rev. C 69, 024602 (2004).

RIKEN Accel. Prog. Rep. 39 (2006)

Many-body correlations among weakly bound neutrons
M. Yamagami[Nuclear structure, pairing correlations, low-frequency vibrational excitations]
One of the most important features of unstable nuclei is the presence of weakly bound nucleons and theircoupling to continuum states. In light neutron-rich nuclei, such as 11 Be and 11 Li, one or two weakly boundneutrons with low orbital angular momentum  form
neutron halos, and their coupling to particle continuum leads to soft E1 excitations. In medium andheavy mass regions, on the other hand, many weakly
bound neutrons are present (e.g., eight weakly boundneutrons above the N = 50 shell closure in 86
28 Ni58 ),and we may expect more exotic collective excitations
as a consequence of the coherent motions among them.
In this study, I clarify several distinctive featuresof many-body correlations in the nuclei close to theneutron drip line by investigating pairing correlations and low-frequency vibrational excitations within
the framework of the Hartree-Fock-Bogoliubov (HFB)
method and quasiparticle random phase approximation (QRPA).
In HFB, the spatial structure of the two-component
single-quasiparticle wave function is determined not
only by the single-particle energy and  but also by
pairing correlations, and the asymptotic behaviors of
the lower component vlj (Elj,n , r) and the upper component ulj (Elj,n , r) are diﬀerent because of the boundary conditions at inﬁnity.1) The spatial structure of thepairing density
1 ρ̃(r) = −(2j + 1)ulj (Elj,n , r)vlj (Elj,n , r)
4πr 2
lj,n

is determined by the competition between the spatial
extent of the lower and upper components, and it isvery sensitive to . Because of the strong coupling tocontinuum states, the contribution of the quasiparticle
states with low- to the pairing density has a spatiallylarge extent that leads to the enhancement of the pairing energy as approaching the neutron drip line2) (seeFig. 1).
The similar competitive mechanism brings about thestrong transition strength of low-frequency vibrational
excitations. Within the QRPA, vibrational excitations
are described by the coherent superposition of twoquasiparticle states, and the coherency is sensitive tothe spatial structure deﬁned by(ph)Fkk (r) = uk (Ek , r) Ô (r) vk (Ek  , r) .

(1)

Here, Ô(r) is one-body transition operator, and Ô(r) =r 2 Y2 (r̂) for isoscalar quadrupole excitations. In Fig. 2,+
the B(E2, 0+
1 → 21 ) values in neutron-rich Ni iso-Fig. 1. The pairing energy obtained by the Woods-Saxon
potential plus HFB pairing model is shown as a functionof λ = ε3s1/2 . The boundary of the continuum region,
where all quasiparticle states are in the continuum, isindicated.

+
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.

topes obtained by the HFB plus QRPA calculation
with Skyrme SLy4 force are shown. The strong coherent motions among weakly bound neutrons, and thecorrelations between neutrons and protons lead to thelarge B(E2) values. By comparing the results of QRPA
with the resonant BCS approximation and RPA, thecrucial role of the change in the spatial structure of thequasiparticle wave functions by pairing correlations in
HFB is evident.2)
References
1) J. Dobaczewski, W. Nazarewicz, T. R. Werner, J. F.
Berger, C. R. Chinn, and J. Dechargé: Phys. Rev. C
53, 2809 (1996).
2) M. Yamagami: Phys. Rev. C 72, 064308 (2005).

19

RIKEN Accel. Prog. Rep. 39 (2006)

Calculations of lowest 2+ states of Ni isotopes using quasiparticle
random-phase approximation
J. Terasaki∗[Nuclear structure, quasiparticle random-phase approximation, unstable nuclei]
The study of unstable nuclei is one of the important
subjects in current nuclear physics. A question may be
addressed for the neutron-rich unstable region as follows: since the neutron drip line is anticipated to be far
from the stable line, many of the nuclei in the region
have much more excess neutrons than excess protons.
Then the nuclear surface may consist of only the neutrons with a tail longer than that of the protons. In addition, coupling eﬀects become important between thediscrete- and continuum-energy single-particle states,as the neutron number approaches the drip lines. Do
any new features, then, appear in the observables of excited states? In this report, we show results of the calculations of the lowest 2+ states of even Ni nuclei fromthe proton to neutron drip lines using the quasiparticle random-phase approximation (QRPA) with theSkyrme and volume-type pairing interactions (for details of the method, see Ref. 1).
The results and experimental data are shown in
Fig. 1. The Ni isotopic chain has a rise in the energy
E2+ and a downward slope of the transition probability B(E2; 0+ → 2+ ) at N = 28 and 40 in the experi-mental data. Normally, this behavior is attributed tothe magic number; that is, there is a shell gap at theneutron chemical potential of the ground state. It is
known, however, that 68 Ni does not show any irregularity in the systematics of the two-neutron separationenergy; thus, this nucleus is not doubly magic. Thisanomaly is explained in terms of the single-particle
level scheme.5) Since the Ni isotopic chain has ananomaly as 68 Ni, it is necessary to investigate if there
occur any other anomalies in more neutron-rich Ni.
The energies are reproduced well by the calculation
with the parameter set SkM∗ . The peak of the theoretical transition probability at N = 36 is, however,shifted from the experimental data, and the decreaseat N = 40 of the calculation is not enough. Currently,
no anomaly is found at the neutron-rich frontier of thischain concerning the experimental data of the lowest
2+ states.
The calculation predicts a decrease in B(E2; 0+ →+2 ) values for N > 46 on average until N = 58. We
have performed the QRPA calculations also using theparameter sets SLy4 and SkO . The global behaviorsof those calculations are similar to that of the SkM∗
calculation; however, the B(E2; 0+ → 2+ ) values of
SLy4 is twice that of the SkM∗ calculation at N = 34
and 36, and an eigenvalue of the QRPA equation with
SkO was found to be imaginary for the two nuclei —therefore, the ground states of SkO are deformed. The
transition probabilities with SLy4 and SkO are almost
0 at N = 40. These three calculations have very similar
B(E2; 0+ → 2+ ) values at each of N = 28, 38, 46, and50, and these values are close to the experimental dataat N = 28 and 38. Thus, it will be interesting to see
if the predictions at N = 46 and 50 are realistic.
The author thanks the members of Motobayashi
Heavy-Ion Nuclear Physics Laboratory for valuable
discussions.
References

Fig. 1. Energies (upper) and B(E2; 0+ → 2+ ) (lower) of
lowest 2+ states of even Ni isotopes. The experimental
data were taken from Refs. 2–4. The Skyrme parameterset SkM∗ and the volume-type delta pairing interaction
are used.

∗

20

School of Physics, Peking University, P.R. China

1) J. Terasaki et al.: Phys. Rev. C 71, 034310 (2005).
2) S. Raman et al.: At. Data Nucl. Data Tables 78, 1(2001).
3) S. Kanno et al.: Private communication.
4) K. Yamada et al.: Eur. Phy. J. A 25, Suppl. 1, 409(2005).
5) K. Langanke et al.: Phys. Rev. C 67, 044314 (2003).

RIKEN Accel. Prog. Rep. 39 (2006)

Shape coexistence of N = 20 isotopes studied
by the Monte Carlo shell model
Y. Utsuno,∗1 T. Otsuka,∗2 T. Mizusaki,∗3 and M. Honma∗4[Nuclear structure, shell model, unstable nuclei]
It has been recently argued1) that shell structure
narrowing toward unstable nuclei plays a primary rolein the disappearance of the magic structure. In thecase of the N = 20 region, the SDPF-M interaction
introduced in a previous paper2) has such a feature.
It is then of much interest to examine the validity ofthis narrowing shell structure by comparing between
experiment and theory.
It is well established that N = 20 isotones near thestability line have several low-lying states dominatedby the intruder state (i.e. the one with two-particle
two-hole excited configurations beyond the N = 20core). Since their positions are sensitively influenced
by the N = 20 shell gap, they are a good measure forthe present purpose. In this study, we systematicallyinvestigate the position of the intruder state obtainedby Monte Carlo shell model (MCSM) calculation withthe valence shell including part of the pf shell. The
numerical computations have been carried out with theAlphleet and Alphleet-2 parallel computer systems as
a RIKEN-CNS collaboration project on large-scale nuclear structure calculations.
Figure 1 compares the energy levels of 36 S between
experiment and calculation. Whereas for the sd-shell
calculation some levels such as the 0+
2 ones are missing,the MCSM calculation, incorporating the lower partof the pf shell, has succeeded in reproducing most ofthem. This agreement indicates that the width of theshell gap in the SDPF-M interaction adopted in thepresent study is appropriate. Together with the resultsof our calculations for unstable nuclei,3) the N = 20
shell gap most probably varies in moving from stable
to unstable nuclei.
We finally stress the importance of the fullconfiguration shell-model calculation by MCSM. In
Fig. 2, the location of the intruder state by MCSM
is compared with the locations with truncated calculations, revealing that the result strongly depends on
the truncation scheme adopted. Hence, not until thecorrelation is properly taken into account can one discuss the position of the intruder state and its relation
to the shell gap.

36
Fig. 2. Excitation energies of the 0+
S and 38 Ar
2 states incompared between the experiment (Exp.) (c) and shellmodel calculations with various truncations. (a) and(b) are the mean-field (Hartree-Fock) approximation
with and without the angular-momentum projection,
respectively. (d), (e) and (f) denote spherical-shellmodel based truncations: (d) is the MCSM calculation,
while (e) and (f) correspond to calculations by truncating up to the 2p2h excitation with and without the
mixing of the 0p0h configurations, respectively.

References

Fig. 1. Energy levels of 36 S compared between experimentand shell-model calculations (see the text for details).
∗1
∗2
∗3
∗4

1) T. Otsuka, R. Fujimoto, Y. Utsuno, B. A. Brown, M.
Honma, and T. Mizusaki: Phys. Rev. Lett. 87, 082502(2001).
2) Y. Utsuno, T. Otsuka, T. Mizusaki, and M. Honma:
Phys. Rev. C 60, 054315 (1999).
3) Y. Utsuno, T. Otsuka, T. Glasmacher, T. Mizusaki, andM. Honma: Phys. Rev. C 70, 044307 (2004).

Japan Atomic Energy Agency
Department of Physics and Center for Nuclear Study, University of Tokyo
Institute of Natural Sciences, Senshu University
Center for Mathematical Sciences, University of Aizu

21

RIKEN Accel. Prog. Rep. 39 (2006)

A search for a uniﬁed eﬀective interaction for Monte Carlo shellmodel calculations (VII)†
M. Honma,∗1 T. Otsuka,∗2,∗3 B. A. Brown,∗4 and T. Mizusaki∗3,∗5[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. We have been investigating2) a
possibility to construct an eﬀective interaction which
can be 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. Since the GXPF1 was determined byusing experimental energy data mainly of stable nuclei, it is a challenging test to apply this interaction todescribe/predict the structure of unstable nuclei.
Figure 1 shows excitation energies Ex (2+1 ) for Ca, Ti
and Cr isotopes. It is seen that the GXPF1 successfully describes the variation of Ex for all these isotope
chains, including the increase of Ex at N = 28 shellclosure. Another increase of Ex appears at N = 32,
which can be interpreted as an indication of a shell
gap resulting from the spin-orbit splitting between the
p3/2 and p1/2 orbits. One interesting result obtained
by GXPF1 is the third increase of Ex at N = 34 for Ca
and Ti, which is attributed to the energy gap between
the neutron f5/2 and p1/2 orbits. However, it turned
56
out that the measured Ex (2+Ti was lower than1 ) forthe GXPF1 prediction by 0.4 MeV.5) A good correspondence between the measured and the calculated
high-spin level structure for 54 Ti suggests the validityof the predicted eﬀective single-particle energy (ESPE)
for the p3/2 and f5/2 orbits at least near N = 32.6)
Therefore, we have searched for a solution of this problem without modifying the ESPE of these orbits.
We have found that the following two modiﬁcations
are enough: (1) The monopole pairing strengths between the orbits f7/2 -f7/2 , f5/2 -p1/2 , and p1/2 -p1/2 aremade more repulsive by 0.2, 0.5 and 0.5 MeV, respectively. (2) The strength of a quadrupole-quadrupole(QQ) interaction [(f5/2 )† (p̃1/2 )](2) · [(p1/2 )† (f˜5/2 )](2)
is made much stronger, i.e., changed from −0.23 to−0.58 MeV, keeping the monopole centroid unchanged.
In total, ﬁve two-body matrix elements have been modiﬁed. This modiﬁed GXPF1 is referred to as GXPF1A.
It can be seen in Fig. 1 that GXPF1A gives better de†
∗1
∗2
∗3
∗4

∗5

22

Condensed from the article in Eur. Phys. J. A 25, Suppl. 1,
499 (2005)
Center for Mathematical Sciences, University of Aizu
Department of Physics, University of Tokyo
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

Fig. 1. Systematics of Ex (2+1 ). Experimental data (closed
circle) are compared to shell-model results obtained bya code MSHELL4) with eﬀective interactions GXPF1(dod-dashed line) and GXPF1A (solid line).

scription of the systematics of Ex (2+ ) than GXPF1
for almost all nuclei. We have conﬁrmed that it isalso true for high-spin states of 54 Ti. In 54 Ca, Ex (2+ )is decreased from 3.8 MeV to 3.0 MeV. Nevertheless,this excitation energy is higher than that of 52 Ca(2.56 MeV experimentally), suggesting the appearanceof the N = 34 shell closure in the Ca isotopes.
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); RIKEN Accel. Prog. Rep. 38, 29 (2005).
3) M. Honma et al.: Phys. Rev. C 65, 061301(R) (2002);
Phys. Rev. C 69, 034335 (2004).
4) T. Mizusaki: RIKEN Accel. Prog. Rep. 33, 14 (2000).
5) S. N. Liddick et al.: Phys. Rev. Lett. 92, 072502 (2004).
6) R. V. F. Janssens et al.: Phys. Lett. B 546, 55 (2002).

RIKEN Accel. Prog. Rep. 39 (2006)

Origin of J = 0 dominance in two-body random interaction†
N. Shimizu∗1 and T. Otsuka∗1,∗2[Nuclear structure, shell model, quantum chaos]The properties of the ground state with a random
interaction have been attracting much interest since
Johnson, Bertsch and Dean reported that the angularmomentum of such a ground state is predominantly
J = 0.1) In other words, in a shell model calculationin the sd shell with 6 neutrons, the ground-state spin
becomes J = 0 with a probability of 76% with randomly generated two-body matrix elements, whereas
only 9.8% of the Hilbert space of 6 neutrons in the sd
shell is J = 0.1)
Since this striking report,1) many studies have been
carried out.2–5) The major points can be summarized
as follows.
(1) A J = 0 ground state is dominant even if thepairing interaction is switched oﬀ in a random
interaction.
(2) No collectivity can be seen.
(3) No general connection to symmetries has been
established.
In particular, the basic mechanism for the preponderance of the J = 0 ground state is not yet established, except for special cases with some algebraic
structures.3,4) We brieﬂy show a possible mechanismin this report.
As in previous works,1–5) the following shell model
Hamiltonian is diagonalized:(L)

H = ΣijklL vijkl ([a†i a†j ](L) [al ak ](L) ),(1)

where some mathematical details are omitted forbrevity. Here, i, j, k and l denote single-particle orbits,
L means their coupled angular momenta, and v stands
for a two-body matrix element. In the discussions below, the v’s are generated as random numbers so as
to obey the Gaussian distribution, and this system isusually called a two-body random ensemble (TBRE).
In the Hamiltonian above, single-particle energies are
assumed to be zero because they are not essential.
In considering the properties of the ground state of
the random interaction discussed above, we propose
the following Ansatz.
• A certain type of random interaction mixes various states strongly in a chaotic manner without
preferences, in eigenstates of a many-body system.
• In this situation, the binding energy can become
maximum when the wave function is invariant†∗1∗2

Condensed from the article in AIP Conf. Proc. 777, 135(2004).
Department of Physics, University of Tokyo
Center for Nuclear Study, University of Tokyo

with respect to transformations of coordinates, because all orientations should be equal.
• The highest symmetries are then given to theground state; a distortion of the wave function
results in a loss of binding energy.
At this point, we note that a randomly generated interaction does not necessarily fulﬁll the above featureof mixing. Namely, such an interaction can have certain dynamics accidentally. If such an accidental dynamics is absent, a random two-body interaction may
mix various states with no preferred orientation in any
sense. The invariance with respect to orientation occurs in the level of a many-body wave function. Thus,
the quantum chaotic mixing can produce the maximum binding energy, while the wave function acquires
the highest symmetry for its relevant transformation.
This will be called the chaotic realization of (highest)
symmetry.
The application of the above mechanism to the rotational invariant system causes the ground state foran even number of particles to be of J = 0. This is thecase well known from Ref. 1. The same mechanism isalso applied to systems having isospin symmetry (T )and parity symmetry (P ), which leads us to conclude
that the ground state for an even number of particles
should be of P = + and T = 0. The detailed veriﬁcation of this mechanism and its applications can befound in Ref. 6.
This work was supported by grants from the MEXT
of Japan, including a Grant-in-Aid for Specially Promoted Research (13002001), and by the RIKEN-CNS
project on nuclear structure calculation.7)
References
1) C. W. Johnson, G. F. Bertsch, and D. J. Dean: Phys.
Rev. Lett. 80, 2749 (1998).
2) R. Bijker and A. Frank: Phys. Rev. Lett. 84, 420 (2000);
Phys. Rev. C 62, 014303 (2000).
3) P. Chau Huu-Tai, A. Frank, N. A. Smirnova, and P. Van
Isacker: Phys. Rev. C 66, 061302 (2002).
4) Y. M. Zhao, A. Arima, and N. Yoshinaga: Phys. Rev.
C 66, 064322 (2002); Phys. Rev. C 66, 064323 (2002).
5) M. Horoi, A. Volya, and V. Zelevinsky: Phys. Rev. C
66, 024319 (2002).
6) T. Otsuka and N. Shimizu: AIP Conf. Proc. 777, 135(2004).
7) N. Shimizu, T. Otsuka, N. Itagaki, T. Mizusaki, M.
Honma, and Y. Utsuno: Annu. Rep. 2004, Center of
Nuclear Study, University of Tokyo, 95, (2004).

23

RIKEN Accel. Prog. Rep. 39 (2006)

Estimation of ground-state energy and spin-zero dominanceN. Yoshinaga,∗1 A. Arima, and Y. M. Zhao∗2[Nuclear shell model, spin-zero dominance]
The ground states of all even-even nuclei have angular momenta equal to zero, I = 0, and positive parity, π = +. This feature was believed to be a consequence of the attractive short-range interaction between nucleons. However, a predominance of I π = 0+
ground states was discovered by Johnson, Bertsch and
Dean in 1998 using the two-body random ensemble(TBRE).1) Since then many eﬀorts have been devoted
to understanding and solving this problem from various viewpoints. See Ref. 2 for a recent review. The
purpose of this Report is to obtain a semi-empirical formula for evaluating the ground-state energy in termsof the average energy (centroid), the standard deviation (width), and the number of spin I states. On thebasis of this formula, we study the problem of spin-zeroground state (0 g.s.) dominance in the presence of the
TBRE.
In order to simplify our argument, we take a single
j n conﬁguration for fermions. The Hamiltonian that
we take is as follows:
2j−1


Ĥ =


(0)
√
2J + 1 GJ A†(J) Ã(J),Here, the parameters a = 0.99 and b = 0.36 are determined phenomenologically.
In Fig. 1 (a), we show P (0)’s of four fermions insingle-j shells. The diamonds are obtained by performing 1000 runs of the TBRE Hamiltonian. The
squares are the empirical prediction,3) Pemp (0)’s, andthe triangles are the results of the present method (thewidth-prediction method). It is seen that both predictions well describe the staggering behavior of P (0)’s,
although a slight disagreement in the case of the empirical prediction is seen for j = 27/2 and j = 29/2.
In Fig. 1 (b), P (I max )’s are shown for three cases. It
is seen that a slight staggering of the TBRE results
is better reproduced by the width-prediction method
proposed in this paper.
To summarize, we proposed a new analytical expression to evaluate the ground-state energy of spin
I states. With this simple formula, a remarkably successful description of the spin I ground-state probabilities was obtained in the presence of the TBRE.

(1)

J=0,even

where GJ ’s are two-body interactions between
fermions, and are assumed to follow the TBRE,
1
ρ(GJ ) = √ exp −G2J /2 .
2π

(2)Then the variance of eigenenergies around the averageenergy (the width squared) is denoted as


2 
2
1
,
(3)
σI {GJ } ≡ Tr Ĥ − ĒI
dI
where dI indicates the dimension of the Hamiltonian
matrix.
Let us estimate the ground-state energy of the
Hamiltonian Ĥ by assuming that it can be expressed interms of the average energy (ĒI ), the width (σI {GJ })and the number of states (dI ) as
(min)

EI

= ĒI − Φ(dI ) σI {GJ } ,(4)where Φ(dI ) is assumed to depend only on the dimension of the Hamiltonian matrix and to take the following form:Φ(dI ) = a ln dI + b.
(5)
∗1
∗2

24

Department of Physics, Saitama University
Department of Physics, Shanghai Jiao Tong University,
China

Fig. 1. (a) P (0)’s of four fermions in single-j shell. The
diamonds are obtained by performing 1000 runs of the
TBRE Hamiltonian. The squares are obtained by the
emp-prediction method and the triangles, by the widthprediction method. (b) The same figure as in (a), but
for P (I max ).

References
1) C. W. Johnson, G. F. Bertsch, and D. J. Dean: Phys.
Rev. Lett. 80, 2749 (1998).
2) Y. M. Zhao, A. Arima, and N. Yoshinaga: Phys. Rep.
400, 1 (2004).
3) Y. M. Zhao, A. Arima, and N. Yoshinaga: Phys. Rev.
C 66, 034302 (2002).

RIKEN Accel. Prog. Rep. 39 (2006)

Band structure in doubly-odd nuclei with mass around 130†
K. Higashiyama∗1 and N. Yoshinaga∗2[Nuclear structure, pair-truncated shell model, chopsticks conﬁgurations]
A number of ∆I = 1 doublet bands built on theunique-parity 0h11/2 valence neutron and proton orbitals have been observed in many doubly-odd nuclei in the mass A ∼ 130 region. These bands had
been interpreted as the manifestation of “chirality”
by Frauendorf and Meng using the three-dimensional
tilted axis cranking model.1) Theoretical investigationsof the doublet bands were carried out within the framework of the phenomenological core-particle-hole coupling model2,3) and the particle-rotor model,4,5) andthe results supported the interpretation of the doublet bands of the chiral structure. These models, however, disregarded the intrinsic degrees of freedom of
the even-even core.
Recently, we have studied the band structure withthe νh11/2 ⊗ πh11/2 conﬁguration in the doubly-odd
nuclei in the mass region by means of a pair-truncatedshell model (PTSM).6) In the PTSM, the shell-modelbasis states of doubly-odd nuclei are constructed byadding an unpaired neutron and an unpaired proton
to the even-even core, which consists of angular momentum zero (S) and two (D) collective pairs. In thiswork we use the pairing plus quadrupole type interaction, whose force strengths are determined to reproduce the energy levels of the even-even nuclei in themass A ∼ 130 region.6)
The theoretical partial level scheme with theνh11/2 ⊗ πh11/2 conﬁguration for 134 La is shown in
Fig. 1. The solid arrows indicate E2 transitions, andthe dotted arrows indicate M 1 transitions. The numerals on the right side of the E2 transitions denotethe B(E2; I → I − 2) values (in e2 b2 ), and those beneath the M 1 transitions denote the B(M 1; I → I −1)
values (in µ2N ). The states within four ∆I = 2 E2++bands with the bandhead states of 8+
1 , 91 , 101 and+
111 are connected by the strong E2 transitions to thesame members of the ∆I = 2 E2 bands, and by thestrong M 1 transitions to the states in the neighboring∆I = 2 E2 bands. This result reproduces well the experimental energy levels of the yrast and yrare bands,
and the ratios B(M 1; I → I − 1)/B(E2; I → I − 2) for
the yrast states.
In search of the microscopic origin of electromagnetic properties, we analyze the reduced matrix elements of M 1 operators, and compare the B(M 1) values for the two-nucleon system of one neutron and one
proton both in the same 0h11/2 orbital with those of
actual calculations. We also calculate the eﬀective angles between the angular momenta of the neutrons andprotons in the 0h11/2 orbitals. The closing of two angular momenta enhances the B(M 1) values, and the
odd-spin yrast states (I) (I ≥ 11) have a fully aligned
conﬁguration of two angular momenta with angularmomentum 11. Similarly, the even-spin yrast states(I − 1), odd-spin states (I − 2) and even-spin states(I − 3) are formed mainly with the conﬁgurationsof angular momenta 10, 9, and 8, respectively. The
schematic illustrations of these conﬁgurations (chopsticks conﬁgurations) are presented below each ∆I = 2
E2 band in Fig. 1. Since quadrupole collectivity plays
an important role in describing the ∆I = 2 E2 bands,
we conclude that the level scheme of 134 La arises fromthe chopsticks conﬁgurations of the unpaired nucleons in the 0h11/2 orbitals, weakly coupled with thequadrupole collective excitations of the even-even partof the nucleus. Similar situations are also obtained in132
Cs, 130 Cs and 132 La.
References

Fig. 1. Partial level scheme of 134 La by PTSM calculation.
†∗1∗2

Condensed from the article in Phys. Rev. C 72, 024315(2005)
Department of Physics, University of Tokyo
Department of Physics, Saitama University

1) S. Frauendorf and J. Meng: Nucl. Phys. A 617, 131(1997).
2) K. Starosta et al.: Phys. Rev. C 65, 044328 (2002).
3) T. Koike et al.: Phys. Rev. C 67, 044319 (2003).
4) D. J. Hartley et al.: Phys. Rev. C 64, 031304(R) (2001).
5) J. Peng, J. Meng, and S. Q. Zhang: Phys. Rev. C 68,
044324 (2003).
6) N. Yoshinaga and K. Higashiyama: Phys. Rev. C 69,
054309 (2004).

25

RIKEN Accel. Prog. Rep. 39 (2006)

Backbending phenomena in A ∼ 130 region described using apair-truncated shell model†
N. Yoshinaga∗1 and K. Higashiyama∗2[Nuclear structure, pair-truncated shell model, backbending phenomena]
Until now, many theoretical investigations have been
carried out on low-lying states of even-even nuclei withmass around 130, which exhibit many interesting features from the soft triaxial deformation. However,there is a limited number of microscopic researches onbackbending phenomena around spin 10 due to thediﬃculty of a theoretical treatment. Recently, we haveproposed the pair-truncated shell model (PTSM) that
describes the nuclear collective motions and the excitations of single-particle degrees of freedom on the samefooting.1,2)
In the SD+H version of the PTSM,1) an evennucleon system is constructed from angular momentum zero (S) and two (D) collective pairs, and noncollective H pairs, which are made by two nucleons in
the 0h11/2 orbital, on the closed-shell core |− as|S ns Dnd H nh Iη = (S † )ns (D† )nd (H † )nh |− ,(1)where I is the total spin of the nuclear state, ηis an additional quantum number required to completely specify the system, and 2(ns + nd + nh ) is
the number of valence nucleons. Then, a basis stateof any even-even nucleus is constructed as a productof |Sνns Dνnd Hνnh Iν ην  and |Sπns Dπnd Hπnh Iν ηπ . In thepresent calculation, we use the pairing plus quadrupole
type interactions.
In Fig. 1, the energy spectrum obtained by the

PTSM is compared with experimental data for 132 Ce.
The calculation reproduces well the energy levels of theeven-spin yrast band, especially the sudden decrease+of level spacing occurring between the 10+
1 and 121
states. The calculated quasi-γ band appears lower in+energy than that in the experiment, but the 5+
1 and 62
states are higher in energy. However, our results give a++good description of the staggering seen in 2+
2 , 31 , 42 ,+and 51 states in the quasi-γ band.
In Fig. 2, calculated B(E2) values in the yrast band
are compared with the experimental data for 132 Ce.
For low-spin states, we suspect that experimental data
might be erroneous, because theoretically it is impos+
sible to produce a smaller value for B(E2; 4+
1 → 21 )++than B(E2; 21 → 01 ) in any existing collective models. A salient feature of the backbending phenomenais the appearance of a drop in the experimental B(E2)value, and it is conﬁrmed that such a behavior is wellsimulated by the PTSM.
From the results of the expectation numbers of D
and H pairs (results not shown), it is found that the
S and D collective pairs play essential roles in describing the low-lying states, and the eﬀect of the alignment of two 0h11/2 neutrons becomes apparent above10+
1 states. We conclude that the truncation scheme
extended to the SD+H subspace by including the intruder conﬁgurations provides an eﬀective and minimal shell model space just enough to describe the yrast
band, γ band and backbending phenomena.

Fig. 2. Comparison of yrast B(E2) values in PTSM withexperimental data (expt.).

Fig. 1. Experimental energy levels of 132 Ce (expt.) compared with those of PTSM calculation.
†
∗1
∗2

26

Condensed from the article in Phys. Rev. C 71, 014305(2005)
Department of Physics, Saitama University
Department of Physics, University of Tokyo

References
1) K. Higashiyama, N. Yoshinaga, and K. Tanabe: Phys.
Rev. C 67, 044305 (2003).
2) N. Yoshinaga and K. Higashiyama: Phys. Rev. C 69,
054309 (2004); K. Higashiyama, N. Yoshinaga, and K.
Tanabe: Phys. Rev. C 72, 024315 (2005).

RIKEN Accel. Prog. Rep. 39 (2006)

Self-consistent random-phase approximation at finite temperature
within the picket-fence model
N. Dinh Dang, A. Volya,∗1 and K. Tanabe∗2[Nuclear structure, random-phase approximation, canonical and grand canonical ensemble]
The random-phase approximation (RPA) is recognized as a powerful method for treating collective dynamics of small amplitudes motion in many-body systems. As with any approximate theory extensions andimprovements immediately followed the original technique. One of major extensions of the RPA is the socalled ﬁnite-temperature random-phase approximation(FT-RPA)1) for the microscopic description of highly
excited nuclei (hot nuclei). Here, as in the standard
statistical approach to nuclear study, the observables
are replaced with the average over the statistical ensemble at a given temperature T , which corresponds tothe excitation energy. Traditionally, in the construction of FT-RPA equations, the collective dynamics isbuilt on thermodynamic states, which are assumed tohave particle occupation numbers given by the FermiDirac distribution of free particles, neglecting the correlations between them. The correctness of this substitution has been taken for granted for years, although it
is clear that the single-particle occupation numbers ingeneral should not follow the distribution of free particles because of correlations between them generated
by interactions.
In the present paper the self-consistent RPA(SCRPA)2) has been extended to ﬁnite temperature,
where the single-particle occupation number is calculated self-consistently. The use of the double-timeGreen function’s method releases the present approachfrom the constraints of perturbation theory and allows
the calculations of the single-particle damping to be
carried out in a straightforward manner. The focus of
the present study is the region where the BCS has no
solution but the RPA is still well valid, so that a recourse to the SCRPA is highly desirable. The resultsof numerical calculations performed within the picketfence model of pairing, whose details are given in,2)
show that, except for the lowest-energy level, the re-∗1∗2

sults obtained within the SCRPA are rather similar to
those given by the RPA, where the occupation numbers
are assumed to have the form of the Fermi-Dirac distribution for non-interacting fermions. As comparedto the RPA, the SCRPA indeed oﬀers a slightly better
agreement with the exact solutions for the thermodynamic quantities such as the total energy and excitation energy as functions of temperature. Nonetheless, the diﬀerence from 1 (0) for the hole (particle)
occupation numbers obtained at T ∼ 0 within the
SCRPA because of the ground state correlations beyond RPA does not aﬀect signiﬁcantly the integrated
quantities obtained within the RPA such as the energyweighted sum of strength and Landau splitting. This
indicates that, in realistic calculations for high-lying
states such as giant resonances, the conventional RPA
at ﬁnite temperature might be suﬃcient and more convenient than the computationally expensive SCRPA.
For the ﬁrst excited states, however, cares should betaken, in particular for light systems at the large interaction strength, to ensure that the correlation eﬀects
are properly included.
References
1) A. V. Ignatyuk: Statistical Properties of Excited Atomic
Nuclei (Energoatomizdat, Moscow, 1983); M. H.
Sommermann: Ann. Phys. (N.Y.) 51, 163 (1983); D.
Vautherin and N. Vinh Mau: Nucl. Phys. A 422, 140(1984); N. Dinh Dang: J. Phys. G 11, 125 (1985); K.
Tanabe and K. Sugawara-Tanabe: Phys. Lett. B 172,
129 (1986); N. Dinh Dang: Z. Phys. A 335, 253 (1990);
K. Tanabe and N. D. Dang: Phys. Rev. C 62, 024310(2000).
2) J. Dukelsky and P. Schuck: Phys. Lett. B 464, 164(1999); J. G. Hirsch, A. Mariano, J. Dukelsky, and P.
Schuck: Ann. Phys. 296, 187 (2002); N. D. Dang: Phys.
Rev. C 71, 024302 (2005).

Department of Physics, Florida State University, USA
Department of Physics, Saitama University

27

RIKEN Accel. Prog. Rep. 39 (2006)

Eﬀect of thermal pairing within thermal shape-ﬂuctuation modelon giant-dipole-resonance width at low temperature
P. Arumugam∗ and N. Dinh Dang
[Nuclear structure, giant dipole resonance, thermal shape ﬂuctuations, pairing]
One of the key issues, which remain to be understood about the hot and rotating nuclei, is the variation of the width of giant dipole resonance (GDR) as
a function of temperature (T ) and spin (I ). Thermal
shape ﬂuctuation models,1) which are quite successful
in hot GDR studies, have failed to explain the recently
observed low-T quenching of the GDR width. Microscopic models such as the phonon damping model attribute this behavior to the ﬂuctuations in the pairing
ﬁeld.2) In the present work, for the ﬁrst time, we attempt to explain this behavior in a relatively macroscopic approach. We have taken care of pairing ﬂuctuations along with the thermal shape ﬂuctuations to calculate the GDR width in hot nuclei. The free energies
are calculated using the Nilsson-Strutinsky method extended to ﬁnite temperature and taking care of thepairing correlations properly. The GDR observables
are related to the shape of the nuclei through a simple anisotropic harmonic oscillator model with a separable dipole-dipole interaction. Considering the ﬂuctuations, the observables are averaged over the shapeparameters and pairing gap.
Our study reveals that the observed quenching of
GDR width at low T in the nuclei 120 Sn and 148 Au canbe understood in terms of simple shape eﬀects causedby the pairing correlations. The ﬂuctuations in pairing leads to a slowly vanishing pairing gap and hence
inﬂuence the structural properties even at moderatetemperatures (∼1 MeV). We observe that the low-T
structure and hence the GDR width are quite sensitive
to the change of the pairing ﬁeld (See Fig. 1). This enables us to validate the pairing prescription and theparameters involved. We infer that if the the ﬂuctuations are treated properly, GDR could be more precise
in yielding the structure information.
References
1)

W. E. Ormand, P. F. Bortignon, and R. A. Broglia:
Phys. Rev. Lett. 77, 607 (1966).

∗

Centro de Fı́sica das Interacções Fundamentais, Instituto
Superior Técnico, Portugal

28

Fig. 1. (a) Pairing gaps for 120 Sn averaged over thermal
shape fluctuations versus temperature. Lines with triangles and crosses are the usual BCS proton and neutron pairing gaps, respectively, while those with diamonds and squares denote the corresponding pairing
gaps, which also include thermal fluctuations of pairing
fields. (b) GDR widths for 120 Sn versus temperature.
Lines with squares, triangles, and diamonds denote thewidths obtained without pairing, including BCS pairing, and thermally fluctuating pairing field from (a),respectively.

2)

N. D. Dang and A. Arima: Phys. Rev. Lett. 80, 4145
(1998); N. D. Dang and A. Arima: Nucl. Phys. A 636,
427 (1998).

RIKEN Accel. Prog. Rep. 39 (2006)

Study of nuclear structure change in framework of
3D-CHFB + GCM
Y. Hashimoto∗1 and T. Horibata∗2[HFB, tilted axis rotation, generator coordinate method]
Description of nuclei within the mean ﬁeld approximation has been considered as an extremely eﬀective
approach and it helps us to understand the dynamics
of nuclear collective motion either from the qualitative or quantitative point of view. The combination of
the Hartree-Fock-Bogoliubov theory and the cranking
model, CHFB, provides us a powerful tool in analyzing the characteristic feature of nuclear collective motion and has revealed the intimate mechanism underlying the nuclear rotational motion step by step. We
expect that the rotational motion of a deformed nucleus can take place about an axis which is tilted fromthe principal axes of the mass quadrupole moment,
tilted-axis rotation (TAR), besides the occurrence of
the usual principal-axis rotation (PAR).1–3) Recently,
a band structure which represents the wobbling motion
occurring about one of the principal axes has been observed.4,5) Since the wobbling mode is considered as aquantum mechanical motion, it requires the existenceof nuclear fully asymmetric shape in three-dimensional
space.
The question we address is the following: What are
the microscopic relationships among the PAR, wobbling motion and TAR? We have started a project onestablishing a theoretical framework with the purposeof understanding the microscopic mechanism underlying the generation of the wobbling motion and thetransformation into the TAR from a uniﬁed viewpoint.
We take advantage of the traditional generator coordinate method (GCM) based on the CHFB in building up the mean ﬁeld. In the ideal case, the nuclear
quadrupole moments and the angles of the rotation
vector tilted from the principal axes are treated as thegenerator coordinates. In the practical case, however,the quadrupole moments are evaluated in the meanﬁeld approximation. Attention is paid to the coordinates of the angles of the rotation vector so that we
can cover the physically important area in an eﬀective
way. Horibata and Onishi performed the GCM calculations based on the two-dimensional cranking along
the prime meridian. They have pointed out several
interesting modes of motion including TAR and wobbling motion within the restricted space on the prime
meridian.1)
We are now at the stage of trial and error to set up∗1∗2

a suitable coordinate system which covers the physicalarea including the wobbling motion and TAR in thethree-dimensional space of angles of the rotation vector. The GCM norm kernel in 182 Os with the angularmomentum J = 18 is calculated in the restricted areaof the “north-east” quarter region including the cranking solution about the principal x-axis, using the pairing plus quadrupole (P+QQ) force. In Fig. 1, we show
the overlap between the wave function of the PA rotation and each wave function of the tilted-axis CHFB
on the mesh points. The PAR state with J = 18 is in
the band crossing region, where Horibata and Onishi
pointed out that the γ -deformation changes markedly
from the g-band to the s-band.1) Nevertheless, no remarkable change in the norm kernel is seen in the ﬁgure
when we go to the east from the prime meridian. We
are now investigating the nuclear structure change ina wide area including the band crossing region.

Fig. 1. Example of norm overlap kernel.

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) S. W. Ødegård et al.: Phys. Rev. Lett. 86, 5866 (2001).
5) I. Hamamoto and G. B. Hagemann: Phys. Rev. C 67,
014319 (2003).

Graduate School of Pure and Applied Sciences, Universityof Tsukuba
Faculty of Software and Information Technology, Aomori
University

29

RIKEN Accel. Prog. Rep. 39 (2006)

Decay modes of heavy and superheavy nuclei predictedby KTUY mass formula†

H. Koura∗1 and T. Tachibana∗2Binding energies and masses, α decay, β decay, decay by proton emission, spontaneousﬁssion, 220 ≤ A

We present a chart of decay modes for α-decay, βdecay, proton emission and spontaneous ﬁssion ranging from light nuclei to superheavy nuclei including
unknown ones using a phenomenological atomic mass
formula1) and some decay models. A bulk term of thismass formula is expressed as a function of proton number Z, neutron number N and mass number A to represent the global feature of atomic masses. Microscopic
features including shell eﬀect and deformation are calculated from a modiﬁed Woods-Saxon single-particle
potential.2) These calculated masses are applied to theestimation of the decay Q values of α-decay, β-decay
and proton emission. For the calculation of the decay rates of α-decay, proton emission and spontaneousﬁssion, a one-dimensional WKB method is applied.3)
Beta decay rate is calculated using the gross theory.4)
Figure 1 shows the calculated partial half-lives ofthese four decays along Z = 101. One of the notablefeatures is that spontaneous ﬁssion is quite sensitive
to nucleon number because of the shell eﬀect. The
curves of proton emission and α decay increase withneutron number, but the proton curve increases more
steeply. The β-decay line is almost ﬂat far oﬀ the βstable region in comparison with other decay modes.
(The peak at N = 154 comes from even-odd eﬀect withsmall Q values.)
Figure 2 shows estimated dominant decay modes in
the nuclear chart including the superheavy nuclidic region. We ﬁnd some regions of ﬁssioning nuclei at aboutZ ≈ 108, N ≈ 168, and nuclei from Z ≈ 100, N ≈ 190

to heavier nuclei. The former region is qualitatively
consistent with recent experimental α-decay chainsmeasured at Dubna, which terminate by ﬁssion. The
latter region indicates that the production of suspecteddouble-magic super heavy nucleus 298 [114]184 by the rprocess nucleosynthesis in supernova is not expected
because β-decay after the r-process near A ≈ 300 or
more is impeded by ﬁssion in that region (See Fig. 2).
We also calculate total half-lives in the “island of stability for the superheavy nuclei,” and obtain 294 Ds184
as the α-decay-dominant nucleus with the longest halflife on the β-stability line of our mass formula of theorder of 100 years, having an ambiguity of 100–1/100
times.
We also estimate nuclei beyond the superheavy ones
and ﬁnd the next “island of stability” on N = 228 in
the neutron-poor region. This results from the larger
ﬁssion barrier height due to the shell closure of 228
for neutrons. Another region with a similar property
is located near N = 126 outside the proton drip line.
In the neutron-rich region, most nuclei are β-decaydominant and have relatively long total half-lives atleast in the order of 1 ms. The partial half-lives ofother decays are longer than that of β-decay.

Fig. 2. Shortest partial half-lives among α-decay, β-decay,
spontaneous fission and proton emission.
Fig. 1. Transition of partial half-lives of four decay modes
along Z = 101.
†
∗1
∗2

30

Condensed from the part of article in Butsuri (Bull. Phys.
Soc. Jpn.) 60, 717 (2005)
Advanced Science Research Center, Japan Atomic Energy
AgencyAdvanced Research Institute for Science and Engineering,
Waseda University

References
1) H. Koura et al.: Prog. Theor. Phys. 113, 305 (2005).
2) H. Koura et al.: Nucl. Phys. A 671, 91 (2000).
3) H. Koura: AIP Conf. Proc. 704, 60 (2004), .
4) T. Tachibana et al.: Proc. Int. Conf. on Exotic Nuclei
and Atomic Masses, Arles, France, 1995-6, edited by
M. de Simon and O. Sorlin (Editions Frontueres, GifYvette, 1995), p. 763.

RIKEN Accel. Prog. Rep. 39 (2006)

Development of 2-D supernova model for r-process nucleosynthesis
Y. Motizuki and H. Madokoro[Supernova explosion, nucleosynthesis]
Rapid neutron-capture process (r-process) nucleosynthesis is necessary to explain the origin of about
half the natural elements heavier than iron. The rprocess is one of the most complex nucleosynthesis to
explore because of the numerous diﬃculties still aﬀecting the description of both the explosive astrophysicalconditions believed to induce the process and the nuclear properties of the exotic neutron-rich nuclei involved.
It should be noted that the r-process site has remained totally unknown to date. Currently, no astrophysical model can consistently predict the neutron
densities required for a successful r-process. The “hotbubble” or postexplosion outﬂows expected from protoneutron stars within seconds after successful corecollapse supernovae1) is thought to be a likely candidate site. However, recent models of spherical (1-D)
neutrino-driven winds from protoneutron stars fail to
induce robust r-process nucleosynthesis up to and beyond the third (A ≈ 195) r-process peak.2) Nevertheless, core-collapse supernovae are generally believed tobe the ﬁrst candidate to induce r-process nucleosynthesis.
Under this situation in which 1-D nucleosynthesis
may have diﬃculties occurring, we developed an axially symmetric (2-D) supernova model to be applied
to r-process nucleosynthesis. Our numerical code wasbased on Ref. 3, in which the mechanism of corecollapse supernovae was investigated. The following
points were our main concerns in the development of
the 2-D model.
(1) The “butterﬂy structure” that appeared in thevicinity of the z-axis in Ref. 3 was removed.
(2) The simulated space was enlarged up to
60,000 km: The equation of state employed was
updated accordingly.
(3) Neutrino-matter interactions and the electron
degeneracy parameter were incorporated without approximations that are valid under hightemperature and high-density conditions, which
are usually considered in simulations of the corecollapse phase and initial (< 500 ms) evolution
phase after the explosion.
(4) The outer boundary condition was changed.
(5) Neutrino luminosity decay and the time evolution of the electron fraction were considered.
(6) Nuclear statistical equilibrium was incorporated
with an accurate treatment of the partition function.
The simulated time was then extended to several

seconds after the shock stall. Figures 1 and 2 show
the entropy distributions in 1-D and 2-D models, respectively. Here, the initial neutrino temperature wastaken to be 5.4 MeV for both models. Comparing
Figs. 1 and 2, we see that entropy evolution remarkably diﬀers between 1-D and 2-D calculations. Since
nuclear reaction rate is determined by the local temperature and density found in entropy maps, it is naturally expected that the resulting nucleosynthesis in
the 2-D model will be very diﬀerent from that in the
1-D model. The r-process nucleosynthetic calculations
employing these models as input of a supernova environment are in progress.

Fig. 1. Entropy map in our 1-D supernova model 4.7 sec
after shock stall.

Fig. 2. The same map as that in Fig. 1, but for 2-D model.

References
1) S. E. Woosley et al.: Astrophys. J. 433, 229 (1994).
2) K. Takahashi et al.: Astron. Astrophys. 286, 857(1994).
3) T. Shimizu et al.: Astrophys. J. 552, 756 (2001).

31RIKEN Accel. Prog. Rep. 39 (2006)

2-D simulation of core-collapse supernova explosion
caused by anisotropic neutrino flux
H. Madokoro, T. Shimizu, and Y. Motizuki[Shock waves, hydrodynamics, stars:neutron, supernova:general]
We study the mechanism of core-collapse supernovae
by using two-dimensional numerical code. Special attention is paid to eﬀects of anisotropic neutrino radiation from the proto-neutron star on the explosion dynamics. We have shown1–3) that anisotropy of ∼ 5–10
percent in the neutrino radiation can greatly increase
the explosion energies when the total neutrino luminosity is ﬁxed, and then lead to a successful explosion.
In these studies, however, the proﬁle of anisotropy in
the neutrino ﬂux was assumed because we did notsolve the region inside the proto-neutron star. It is
expected that anisotropy will naturally appear as a result of multidimensional eﬀects such as rotation andconvection in the course of core-collapse, bounce, andshock propagation. Therefore, as the next step, we
have performed two-dimensional core-collapse simulations starting from the rotating progenitor model developed by Heger et al.4)
Figure 1 shows a contour plot of entropy distribution with velocity ﬁelds at t = 20 ms after bounce. It
is seen that the shock wave is stalled at r ∼ 100 km.
The radius of the neutrino sphere is r ∼ 52 km (on thepole) and ∼ 55 km (on the equatorial plane), which
is deformed in a oblate shape due to rotation. We
can estimate the degree of anisotropy in the neutrino
ﬂux as follows: If the deformed neutrino sphere is regarded as a Maclaurin spheroid, the ratio of the neutrino ﬂux along the polar axis (lz ) to that on the equatorial plane (lx ) becomes lz /lx = Rx /Rz ,1) where Rx
and Rz represent the equatorial and polar radius of
the neutrino sphere, respectively. Our calculation gives
Rx /Rz ∼ 1.05. This implies that the neutrino ﬂux has
an anisotropy of ∼ 5%.
In Fig. 2, a result of our previous study with assumed anisotropy1–3) is shown. We can see that theanisotropy of ∼ 5%, which we obtained in the present
core-collapse simulation, is suﬃcient to increase theexplosion energy compared with that of the sphericalmodel.

Fig. 2. Evolution of explosion energies for models under assumption of anisotropic neutrino radiation: anisotropy
of 5% (solid line), of 10% (dashed line), of 15% (dotdashed line), and spherical explosion (dotted line).
Note that anisotropic models will explode, while thespherical model fails.

References
Fig. 1. Contour plot of entropy distribution with velocity
fields at t = 20 ms after bounce for rotating model. The
stalled shock wave is represented by crowded contour
lines at r ∼ 100 km. The deformed neutrino sphere islocated at r ∼ 52–55 km.

321) 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).
4) A. Heger et al.: Astrophys. J. 528, 368 (2000).

RIKEN Accel. Prog. Rep. 39 (2006)

EOS dependence of supernova neutrinos
from the collapse of massive stars
K. Sumiyoshi,∗1,∗2 S. Yamada,∗3 H. Suzuki,∗4 and H. Toki∗5[Equation of state, supernova, neutrino]
Massive stars having more than ∼10 solar masses(M ) end their lives by the gravitational collapse after
the iron core is formed. For the massive stars of ∼10–
20 M , the spectacular events known as supernova explosions occur through the launch of shock wave by
the bounce of core at high density. Stars more massive than ∼20 M may have diﬀerent fates since theyusually have larger iron cores. They are too massive
to have the stellar explosion and the outcome will bea formation of black hole. The detection of neutrinos
is a clear and unique identiﬁcation of such events andit is important to quantitatively predict the neutrinosignals from the black hole formation.
To predict the time proﬁle of neutrino burst and theenergy spectrum of neutrinos during the evolution, we
perform elaborated simulations of ν-radiation hydrodynamics under the spherical symmetry.1) We follow
the evolution from the beginning of gravitational corecollapse to ﬁnd when and how the black hole is formed
from a massive star. In order to determine the ﬁnal
fate, we perform the simulations for a long time scale(∼1 s), which has not been explored before.
The microphysics such as equation of state (EOS)of dense matter is playing signiﬁcant roles2) in the νradiation hydrodynamics. In order to assess the inﬂuence of dense matter, we adopt two sets of realistic
EOS for the simulations of black-hole-forming massive
stars. We make comparisons of the evolutions of central core from the initial collapse up to the black holeformation for the ﬁrst time. This enables us to probedense matter at extremely high density and temperature through the properties of neutrino signals.
The subroutine of EOS by Lattimer and Swesty (LSEOS),3) which is a conventional choice, is based on thecompressible liquid drop model for nuclei together withdripped nucleons. On the other hand, the data table of
EOS by Shen et al. (SH-EOS)4) is newly constructedin the relativistic nuclear many body frameworks. It
is to be noted that the nuclear interaction to derive
SH-EOS is constrained by the properties of unstable
nuclei, which are available recently in radioactive nuclear beams facilities.
The average energies of neutrinos emitted from thecentral core of a 40 M star in two simulations with LS∗1
∗2
∗3
∗4
∗5

Numazu College of Technology
National Astronomical Observatory of Japan
Science & Engineering, Waseda University
Faculty of Science and Technology, Tokyo University of Science
Research Center for Nuclear Physics, Osaka University

EOS and SH-EOS are shown as a function of time after
bounce in Fig. 1. The rise of average energies comesfrom the temperature increase by the contraction of
newly born neutron stars since its mass increases dueto the matter accretion. The mass of neutron star ﬁnally exceeds the maximum mass and the black holeis formed by the dynamical collapse. The end points
in the ﬁgure correspond to the births of black hole.
It is interesting that the diﬀerent timing of black holeformation for models with LS-EOS and SH-EOS is reﬂected in the diﬀerent timing of the termination of neutrino emissions. The LS-EOS is softer than SH-EOS,
therefore, it leads to the smaller maximum mass andthe earlier formation of black hole. This diﬀerence inneutrino signals will provide us with the information
on EOS.5) A terrestrial detection of neutrino bursts
from the black hole formation in future will put a new
constraint on the EOS at high density and temperature.

Fig. 1. Average energies of νe (solid), ν̄e (dashed) and νµ/τ
(dot-dashed) as a function of time after bounce in two
simulations with LS-EOS (left) and SH-EOS (right).

References
1) K. Sumiyoshi, S. Yamada, H. Suzuki, H. Shen, S. Chiba,
and H. Toki: Astrophys. J. 629, 922 (2005).
2) K. Sumiyoshi, H. Suzuki, S. Yamada, and H. Toki:
Nucl. Phys. A 730, 227 (2004).
3) J. M. Lattimer and F. D. Swesty: Nucl. Phys. A 535,
331 (1991).
4) H. Shen, H. Toki, K. Oyamatsu, and K. Sumiyoshi:
Nucl. Phys. A 637, 435 (1998).
5) K. Sumiyoshi, S. Yamada, H. Suzuki, and S. Chiba:
submitted to Phys. Rev. Lett.

33

RIKEN Accel. Prog. Rep. 39 (2006)

Momentum correlation in the three-body decay ofhigh-density K̄ nuclear clusters: N N N K − → N + N + Λ†
P. Kienle,∗1 Y. Akaishi,∗2 and T. Yamazaki∗3[Kaonic nuclei]
A method is proposed to probe the size of denseK̄ nuclear clusters1–4) by observing the momentum
correlation in their 3-body decay products, such as[pppK − ](T =1) → Λ + p + p and [ppnK − ](T =0) →Λ + p + n. The calculated momentum correlation pattern expressed in a Dalitz plane shows characteristicfeatures, reﬂecting the size/density and the angularmomentum of the parent K̄ cluster, as shown in Fig. 1.
The ridges on the right-hand and left-hand sides correspond to the “participant” proton and the “spectator”
proton, respectively. For the “normal core” the ridges
are very sharp, peaked around at Xmax and at Xmin ,reﬂecting that the spectator nucleon carries out only asmall momentum. On the other hand, for the “shrunkcore,” the variation is very much broadened, since thespectator nucleon takes out a larger momentum andin turn the participants momenta are reduced. Thus,
the nuclear shrinkage predicted can be experimentally
examined by observing the three-body correlation.
References
1) Y. Akaishi and T. Yamazaki: Phys. Rev. C 65, 044005(2002).
2) T. Yamazaki and Y. Akaishi: Phys. Lett. B 535, 70(2002).
3) A. Doté, H. Horiuchi, Y. Akaishi, and T. Yamazaki:
Phys. Lett. B 590, 51 (2004).
4) A. Doté, H. Horiuchi, Y. Akaishi, and T. Yamazaki:
Phys. Rev. C 70, 044313 (2004).

Fig. 1. Calculated density distributions in three-dimensional presentation of Dalitz plots in the decay of
ppnK − (T = 0) (Upper) and pppK − (T = 1) (Lower) of M = 3115 MeV/c2 . (Left) “shrunk core” and(Right) “normal core.”

†
∗1
∗2
∗3

34

Condensed from the article in Phys. Lett. B 632, 187 (2006)
Technische Universität München and Stephan Meyer Institute, Germany
College of Science and Technology, Nihon University
Department of Physics, University of Tokyo

RIKEN Accel. Prog. Rep. 39 (2006)

Shear viscosity coeﬃcient studied by molecular dynamics
Y. Akimura,∗1,∗2 T. Maruyama,∗2 N. Yoshinaga,∗1 and S. Chiba∗2[Quark gluon plasma, viscosity, molecular dynamics]
From experimental analyses,1–3) it is considered thatquark gluon plasma (QGP) produced in RHIC is not a
weakly coupled gas but a strongly coupled liquid. The
ratio of shear viscosity to entropy is a good criterion
for determining whether a system behaves as a gas ora liquid. A theoretical study by quenched lattice QCD
was performed on the matter viscosity at above thecritical temperature.4) The viscosity per entropy density η/s was found to be much smaller than 1, whichindicates the matter is extremely smooth. However,the dynamics of quarks and anti-quarks, which seems
very important, was not considered in the study. Here,
we study the shear viscosity of quark matter by molecular dynamics (MD) which is a natural framework forinvestigating dynamical quantities.
We prepare a cubic box in which the same numberof u, d quarks and their anti-quarks are contained, andimpose a periodic boundary condition. The number ofquarks and anti-quarks for q q̄ matter is determined using a derivative of the thermodynamical potential withrespect to the chemical potential, where no interaction
is assumed. To simulate quark many-body system at
a ﬁnite temperature, we give appropriate initial values
for the position and momentum of i-th quark, Ri and
Pi , and solve the following equations,
Ṙi =

∂H
,
∂Pi

Ṗi = −∂H,
∂Ri

and P is the pressure.
Simulation is performed using a box size of 10 fm
for a low-temperature region and 4 fm for a hightemperature region. Figure 1 shows the ratio ofshear viscosity to the entropy density. In the lowtemperature region, where quarks form mesons, η/sis larger than one. The value decreases as the temperature increases. Around 130 MeV, where quarks aredeconﬁned, η/s takes a value smaller than one. Thisvalue is of the same order as that of the lattice calculation of Ref. 4 and suggests that quarks behave likea liquid. Above 130 MeV, η/s increases linearly. Thismeans that the motion of quarks is more dominant
than their interaction at high-temperature. If an eﬀectof the asymptotic freedom was taken into account, η/sat high-temperature would become larger. The investigation of viscosity for the ﬁnite baryon density is inprogress.

(1)

where H is the Hamiltonian used in Ref. 5 without themeson exchange potentials. The equations of motion
were solved for several thousands fm/c after the system reached equilibrium. The shear viscosity η can becalculated using the Green-Kubo relation,6)
 ∞


1
Jxy (t) · Jxy (0) dt,
η=(2)
Teﬀ V 0where Teﬀ is the eﬀective temperature deﬁned in Ref. 7
and Jxy is the stress tensor in the x-y direction,



N 

∂H
∂H
Jxy (t) =
·
−
·
P
xi
+
(3)
i,y .
∂yi
∂Pi,x
i=1
To discuss the ratio of the shear viscosity to the entropy density, thermodynamic quantities in MD are
calculated as


N
ε+P
1
∂H
s=
, P V = N Teﬀ +Ri · −
,(4)
Teﬀ
3 i=1
∂Ri

Fig. 1. Temperature dependence of ratio of shear viscosity
to entropy density for q q̄ matter.

References
1) PHOBOS Collaboration, B. B. Back et al.: Nucl. Phys.
A 757, 28 (2005).
2) STAR Collaboration, J. Adams et al.: Nucl. Phys. A
757, 102 (2005).
3) PHENIX Collaboration, K. Adcox et al.: Nucl. Phys. A
757, 184 (2005).
4) A. Nakamura and S. Sakai: Phys. Rev. Lett. 94, 072305(2005).
5) Y. Akimura et al.: Eur. Phys. J. A 25, 405 (2005).
6) J. P. Hansen and I. R. McDonald: Theory of Simple
Liquids, 2nd ed. (Academic Press, London, 1986).
7) S. Chikazumi et al.: Phys. Rev. C 63, 024602 (2001).

where s is the entropy density, ε is the energy density∗1∗2

Department of Physics, Saitama University
Japan Atomic Energy Agency

35

RIKEN Accel. Prog. Rep. 39 (2006)

Color superconductivity and neutron star structure†
S. Lawley,∗1 W. Bentz,∗2 and A. W. Thomas∗3[Matter at high density, neutron matter]
The equation of state (EOS) at very high baryon
densities, like in the center of a neutron star, is avery active ﬁeld of recent research. Theoretically it
is expected that the matter undergoes a phase transition from nuclear matter (NM) to quark matter (QM),
where the latter is most likely in a color superconducting state (SQM). The basic parameter which controls
this phase transition is the pairing strength between
the quarks in the scalar diquark channel (J = T = 0,color 3). In this work, we report on the results forthe equation of state of charge neutral matter in βequilibrium and the masses of compact stars obtainedby using the ﬂavor SU(2) Nambu-Jona-Lasinio (NJL)
model, which is an eﬀective quark theory based on
QCD.
The eﬀective potential for NM is1) V NM = Vvac +VN + Vω + Vρ + Ve , where the vacuum term Vvac accounts for the polarization of the quark Dirac sea, VN
represents the Fermi motion of the nucleons which
are described as quark-diquark bound states in the
NJL model, Vω and Vρ arise from the isoscalar andisovector mean vector ﬁelds respectively, and Ve is
the electron contribution. For QM we have2) V QM =Vvac + VQ + Ve + V∆ , where the vacuum and electron
terms are as above and the term for the Fermi motionof the quarks VQ is analogous to VN , but referring toup and down quarks. The eﬀect of the quark pairingis expressed by the term V∆ , which involves the gap
and a coupling constant (Gs ) for the pairing interaction in the scalar diquark channel, which we express
as Gs = rs Gπ . Here rs is a parameter, and the coupling constant in the pionic channel (Gπ ) is ﬁxed byreproducing the pion mass. The NM/QM mixed stateis constructed by using the Gibbs conditions of phaseequilibrium.3)
In Fig. 1 we show the EOS corresponding to thecases rs = 0 and rs = 0.25, and in Fig. 2 we show
the resulting star sequences. (The results for the pure
NM case are also shown for comparison.) In the ﬁrst
case, for central densities between 3.7ρ0 and 6.0ρ0(ρ0 = 0.15 fm−3 ), stable hybrid stars exist with a
NM/QM phase in the center. In the second case, stablehybrid stars exist with central densities between 2.3ρ0
and 5.0ρ0 with a very small region of NM/SQM mixed
phase in the center, and for central densities between
6.0ρ0 and 15.0ρ0 stable quark stars exist, which are
†
∗1
∗2
∗3

36

Condensed from an article by S. Lawley, W. Bentz, andA. W. Thomas: Phys. Lett. B 632, 495 (2006)
Department of Physics, University of Adelaide, Australia
Department of Physics, Tokai University
Jeﬀerson Laboratory, USA

Fig. 1. Pressure vs. baryon density for pure NM (solid line)
and the transition to QM for rs = 0 (dashed line) andrs = 0.25 (dotted line).

Fig. 2. Star masses vs. central density for the 3 cases ofFig. 1.

composed of SQM in the central region. Comparisonof these two cases indicates that color superconductivity has a major eﬀect on the EOS: With increasing rs ,both the density and the pressure for the phase transition to QM are reduced, the EOS becomes softer, andthe star masses decrease for given central density.
References
1) W. Bentz and A. W. Thomas: Nucl. Phys. A 696, 138(2001).
2) W. Bentz, T. Horikawa, N. Ishii, and A. W. Thomas:
Nucl. Phys. A 720, 95 (2003).
3) N. K. Glendenning: Compact Stars (Springer, New
York, 2000).

RIKEN Accel. Prog. Rep. 39 (2006)

The polarized EMC eﬀect†
I. C. Cloet,∗1 W. Bentz,∗2 and A. W. Thomas∗1[Nuclear structure functions, spin dependence, eﬀective quark theories]
Recent works1) have shown that the EMC eﬀect forthe spin-independent nuclear structure functions canbe successfully described in terms of the self consistentscalar and vector ﬁelds which couple to the quarks inside the nucleons. The individual nucleons in this approach are described as bound states of a quark anda diquark, where both the scalar and axial vector diquark channels are taken into account.2) Predictions
for the spin-dependent counterpart of the EMC eﬀect
have also been made in this model.
The calculations of Ref. 1 have been carried out innuclear matter, and in this work we present results forﬁnite nuclei. First studies of the polarized EMC eﬀect
should concentrate on light to medium heavy nuclei
with valence proton particles or holes carrying the nuclear spin. Examples are 11 B and 15 N, which have arelatively simple structure so that one can investigate
the eﬀects of the medium on the quark substructure
without too many complications caused by the nuclear
many body problem.
We report on the results for 11 B in this work. It is
assumed that the nucleons move in average scalar andvector ﬁelds, for which we take Woods-Saxon forms
for simplicity. From the wave functions we obtain thespin dependent light cone momentum distributions of
the nucleons.3) To get the quark distributions in the
nucleons, we use the quark-diquark model of Ref. 2,
where the mean nuclear ﬁelds are incorporated into
the constituent quark and diquark propagators. The
convolution formalism is then applied to calculate thequark light cone momentum distributions in the nucleus.
The results for the polarized up and down quark distributions for the p3/2 proton hole state are shown in
Fig. 1 for the low energy scale Q0 = 0.4 GeV. The
dotted line shows the distribution in a free proton,
the dashed line shows the result including the eﬀective mean scalar ﬁeld which applies to the p3/2 state,
the dotted-dashed line shows the result including the
Fermi motion, and the solid line also includes the effective mean vector ﬁeld. Figure 2 shows the resulting
polarized EMC ratio for the nucleus 11 B (dashed line)
in comparison to the unpolarized one (solid line) andthe experimental data for the 12 C nucleus. For theunpolarized case, where all nucleons contribute, thisratio is deﬁned as usual by F 2A /F2N , where F 2A isthe nuclear structure function per nucleon and F2N is†∗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

the average of the free proton and neutron structure
functions. For the polarized case, the ratio is deﬁned as
g1A/P , where we divide out the nuclear polarization
g1p
factor (P ) so that the ratio becomes 1 for the case of no
medium modiﬁcations. The comparison of these two
ratios shows that the medium modiﬁcations are more
important for the case of the spin-dependent structure
function than for the spin-independent one.

Fig. 1. The polarized up and down quark distribution forthe p3/2 proton state.

Fig. 2. Polarized (dashed line) and unpolarized (solid line)
EMC ratios for 11 B. The experimental data of the unpolarized ratio for 12 C are shown for comparison.

References
1) I. C. Cloet, W. Bentz, and A. W. Thomas: Phys. Rev.
Lett. 95, 052302 (2005).
2) I. C. Cloet, W. Bentz, and A. W. Thomas: Phys. Lett.
B 621, 246 (2005).
3) R. L. Jaﬀe and A. Manohar: Nucl. Phys. B 321, 343(1989).

37

RIKEN Accel. Prog. Rep. 39 (2006)

Measurement of the vector analyzing power for the p+6 He elastic
scattering at 71 A MeV using polarized proton solid target
S. Sakaguchi,∗1 T. Uesaka,∗1 T. Wakui,∗2 N. Aoi, Y. Hashimoto,∗3 M. Ichikawa,∗4 Y. Ichikawa,∗5 K. Itoh,∗6
M. Itoh,∗2 H. Iwasaki,∗5 T. Kawabata,∗1 T. Kawahara,∗7 H. Kuboki,∗5 Y. Maeda,∗1 R. Matsuo,∗4 T. Nakao,∗5
H. Okamura,∗2 H. Sakai,∗5 N. Sakamoto, Y. Sasamoto,∗1 M. Sasano,∗5 Y. Satou,∗3 K. Sekiguchi, M. Shinohara,∗3
K. Suda,∗1 D. Suzuki,∗5 Y. Takahashi,∗5 A. Tamii,∗8 K. Yako,∗5 and M. Yamaguchi[Nuclear structure, polarized target, unstable nuclei]
To extract a variety of spin-dependent information
on nuclear reaction and the structure of unstable nuclei, we have constructed a polarized proton solid target applicable in RI beam experiments.1) The target
was ﬁrst used in an experiment in 2003, where analyzing power was measured for the p + 6 He elastic scattering at 71 A MeV.2) Here, we obtained a result that directly contradicts the predictions of optical models.3,4)
To derive the underlying physics, we carried out ananalyzing power measurement for the p+6 He elastic
scattering with higher statistics and improved resolution in 2005. Simultaneous with the analyzing power
measurement, we also measured the target polarization via the p+4 He elastic scattering at 80 A MeV
whose analyzing power is already known.5) The polarization measurement was carried out because the absolute value of the polarization cannot be, in our target, determined by nuclear magnetic resonance (NMR)
measurement alone, whereas the value is required forthe normalization of analyzing power.
The experiment was performed at RIKEN Accelarator Research Facility using a 92 A MeV 12 C primarybeam. A 71 A MeV 6 He beam was separated using
the RIKEN Projectile Fragment Separator (RIPS) andthe beam bombarded the polarized proton solid target
with a thickness of 113 mg/cm2 . The typical beam intensity was 300 kcps. The target material was a naphthalene crystal with a size of φ14 mm × 1 mmt . For
the elimination of spurious asymmetry, the directionof the polarization was reversed three times during thebeam time by the 180-degree NMR pulse method. A
schemetic view of the experimental setup is shown in
Fig. 1. Leading particles were detected using a multiwire drift chamber (MWDC) and ∆E − E plastic scintillator hodoscopes with thicknesses of 5 and 100 mm.
Recoiled particles were detected using single-wire drift
chambers and CsI scintillators on the left and rightsides of the beam line.
p+4,6 He elastic scattering events were selected by
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8

38

Center for Nuclear Study, University of Tokyo
Cyclotron and Radioisotope Center, Tohoku University
Department of Physics, Tokyo Institute of Technology
Department of Physics, Tohoku University
Department of Physics, University of Tokyo
Department of Physics, Saitama University
Department of Physics, Toho University
Research Center for Nuclear Physics, Osaka University

Fig. 1. Schematic view of experimental setup.

identifying the particles and requiring a kinematicalconsistency for them. By counting left/right (L/R)
scattering events in the cases of polarization up/down(↑/↓), we obtained yields as NL↑ , NR↑ , NL↓ and NR↓ .
Analyzing power and target polarization are deduced
using the relation

N↑L · N↓R − N↓L · N↑R
1


Ay =
,
(1)
Py N↑L · N↓R + N↓L · N↑R
by cancelling spurious asymmetry. The target polarization was 13.5 ± 3.9% on the average and 19.7 ± 5.6%
at the maximum. The preliminary result of analyzing
power is shown in Fig. 2 as indicated by the closed
circles. Further analysis is now in progress.

Fig. 2. Analyzing power for p
+6 He, 6 Li, and 4 He.

References
1) T. Wakui et al.: Nucl. Instrum. Methods Phys. Res. A
550, 521 (2005).
2) M. Hatano et al.: Eur. Phys. J. A 25, 255 (2005).
3) S. P. Weppner et al.: Phys. Rev. C 61, 044601 (2000).
4) D. Gupta et al.: Nucl. Phys. A 674, 77 (2000).
5) H. Togawa et al.: RCNP Ann. Rep. 1987, 1.

RIKEN Accel. Prog. Rep. 39 (2006)

Inelastic proton scattering of 6 He
Y. Hashimoto,∗1 T. Nakamura,∗1 Y. Satou,∗1 T. Sugimoto,∗1 Y. Kondo,∗1 N. Matsui,∗1 T. Okumura,∗1
T. Nakabayashi,∗1 M. Shinohara,∗1 N. Fukuda, S. Takeuchi, N. Aoi, T. Gomi, Y. Yanagisawa,
T. Motobayashi, T. Kobayashi,∗2 H. Otsu, Y. Matsuda,∗2 N. Endo,∗2 M. Kitayama,∗2 Y. Togano,∗3
S. Kawai,∗3 H. Sakurai, H. J. Ong,∗4 T. K. Onishi,∗4 M. Tamaki,∗5 S. Shimoura,∗5 and M. Ishihara
Nuclear reactions: 6 He(p,p )6 He, inelastic proton scattering
We have investigated the ﬁrst 2+ excited state at
Ex = 1.8 MeV of 6 He by proton inelastic scattering.
6
He has a two-neutron halo structure characterized bya three-body nature with no bound binary subsystems,
which is called the Borromean system. Previous theoretical studies predicted that the ﬁrst 2+ excited stateof 6 He is a three-body related resonance.1–3) Recently,
the three-body breakup 6 He → 4 He + n + n was studied using a 6 He ion beam of 240 MeV/nucleon incident
on carbon and lead targets at GSI.4) At GANIL, inelastic proton scattering of 6 He was studied using a
missing mass method, where they detected only 4 He
and a recoiled proton.5,6) Here, we study the structureof 6 He(2+ ) using an invariant mass method, where wehave measured all the decay products from this state.
We extract the energy spectrum and the angular distribution, which may have information on the three-bodystructure. We also study the two-body correlations byexamining the Dalitz plot.
The experiment was performed at the RIPS beamline at the RIKEN Accelerator Research Facility. A secondary 6 He beam was produced using a
100 MeV/nucleon 18 O primary beam incident on a 9 Be
target with a 1.1 g/cm2 thickness. The secondary
beam was puriﬁed through the RIPS separator, andwas transported to the last focal point of RIPS (F3)where a secondary target of liquid hydrogen with athickness of 229 mg/cm2 was installed. Particle identiﬁcation of the incident beam was achieved using the∆E and time of ﬂight (TOF) measured at the second focal point of RIPS (F2) event by event. The
intensity of 6 He separated by RIPS was approximately
2×104 cps with a purity of 97%. The energy was
70 MeV/nucleon at F3. The position and incident angle of the secondary beam were measured using twoparallel-plate avalanche counters. The magnetic spectrometer system equipped with a multiwire drift chamber, a drift chamber, and a plastic scintillator hodoscope (HOD) was used for detecting a charged particle fragment. Particle identiﬁcation of this fragment
was carried out by combining ∆E and TOF information from HOD, and magnetic rigidity informationfrom the drift chambers. Three layers of plastic scintil∗1
∗2
∗3
∗4
∗5

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

lator arrays were used for detecting two neutrons. The
upstream, middle and downstream layers had 26, 30
and 30 pieces of plastic scintillator rod, respectively.
The constituent rod of the ﬁrst and second layers had
dimensions of 6×6×214 cm3 , and that of the third layer
had dimensions of 6×6×108 cm3 . By imposing theproper kinematical condition, we excluded cross-talkevents, which could be mixed with true two-neutron
events.
Figure 1 shows the preliminary relative energy spectrum of 4 He + n + n. We have analyzed this peak byﬁtting it with a Breit-Wigner parameterization for the
resonance and arbitrary background function, whichroughly explains the strength of approximately 2 MeV.
The obtained resonance energy is 0.85±0.04 MeV in
relative energy, which is consistent with the known
value of 0.824.4) The total inelastic cross section is
18.0±0.7(stat.)±1.9(syst.) mb (preliminary). Further
analysis is now in progress including the study of threebody decay characteristics using the Dalitz plot.

Fig. 1. Relative energy spectrum observed for 1 H(6 He,
4
He+n+n) reaction at 70 MeV/nucleon. The data are
fitted with the Breit-Wigner function (solid curve) plus
background (dashed curve).

References
1) B. V. Danilin et al.: Phys. Rev. C 55, R577 (1997).
2) B. V. Danilin, I. J. Thompson, J. S. Vaagen, and M. V.
Zhukov: Nucl. Phys. A 632, 383 (1998).
3) E. Nielsen, D. V. Fedorov, A. S. Jensen, and E. Garrido:
Phys. Rep. 347, 373 (2001).
4) T. Aumann et al.: Phys. Rev. C 59, 3 (1999).
5) A. Lagoyannis et al.: Phys. Lett. B 518, 27 (2001).
6) S. V. Stepantsov et al.: Phys. Lett. B 542, 35 (2002).

39

RIKEN Accel. Prog. Rep. 39 (2006)

Confirmation of validity of s-wave approximation for 6 Li(d,p0 )reaction at incident energy of 90 keV
M. Yamaguchi, Y. Tagishi, and M. Tanifuji∗[Nuclear reaction, resonance]
We conﬁrmed the validity of the s-wave approximation for 6 Li(d,p0 ) reaction. In our previous publications1–3) we proposed a novel method for studying reaction mechanism by extracting resonant component
from analyzing powers at very low incident energy, andapplied it to the 6 Li + d reactions which are aﬀectedby a resonance level of 8 Be at Ex = 22.2 MeV. In
this study, we assumed the isotropic behavior of thereaction, which was to be conﬁrmed later in a separate
measurement.
In the framework of IMA (Invariant Amplitude
Method),4) the angular distribution of the diﬀerential
cross section for 6 Li(d, p0 ) reaction is represented as
dσp (θ)= a(1 + 2Pσ cos θ),dθ(1)where a and Pσ are arbitrary parameters. Using theyields of proton and α-particle, Np (θ) and Nα (θ), respectively, the yield ratio of proton and α-particle isrepresented as
X(θ) ≡ Np (θ)/Nα (θ) = (a/b) × (1 + 2Pσ cos θ), (2)where b is the diﬀerential cross section of 6 Li(d, α),which is isotropic. X(θ) is canceled by the diﬀerences in solid-angles between the detectors, and becomes isotropic if the s-wave approximation is valid.
The experiment was performed at the Universityof Tsukuba, Tandem Accelerator Center (UTTAC).
The scattering chamber was directly connected to thedeuteron ion source. The deuteron beam was accelerated up to 90 keV and impinged on a target. Figure 1
shows the placement of the detectors and target, which
was a layer of lithium carbonate Li2 CO3 10 µg/cm2

thick on an aluminum backing 15 µm thick. The enrichment of 6 Li was 95%. The energy loss in the layerof lithium carbonate was approximately 8 keV. A slit
with a diameter of 5 mm was placed at the distance of
150 mm upstream from the target. We placed 12 SiSSDs around the target from the scattering angle of 0◦
to 165◦ every 15 degrees for measuring the proton andα-particle. Each detector was placed at the distanceof 140 mm from the target and has the solid angle of
2.6 msr.
The experimental results are shown in Fig. 2. The
horizontal axis is the scattering angle in the center
mass system. The vertical axis is the yield ratio,
X(θ). The error bars only include statistically signiﬁcant values. The quantities a/b and Pσ are treated as
free parameters and determined to ﬁt the experimental data of X(θ) by the maximum-likelihood method.
The derived parameters are Pσ = 0.009 ± 0.014 anda/b = 0.572 ± 0.011. We found that the anisotropic
parameter, Pσ , is consistent with zero and hence themixture by the p-wave is negligible.

Fig. 2. Yield ratio of proton and α-particle. The solid line
is for Pσ = 0.009 and a/b = 0.572. The dashed lines
are for Pσ = 0.009 ± 0.014 and a/b = 0.572 ± 0.011.

References

Fig. 1. Layout in scattering chamber.
∗

40

Department of Physics, Hosei University

1) M. Yamaguchi, Y. Tagishi, Y. Aoki, T. Iizuka, T.
Nagatomo, T. Shinba, N. Yoshimaru, Y. Yamato, T.
Katabuchi, and M. Tanifuji: in press.
2) M. Yamaguchi, N. Yoshimaru, and Y. Tagishi: UTTAC
Ann. Rep. 2003, 17 (2004).
3) T. Iizuka, M. Yamaguchi, N. Kawachi, N. Yoshimaru,
K. Shiga, and Y. Tagishi: UTTAC Ann. Rep. 2001, 32(2002).
4) M. Tanifuji and H. Kameyama: Phys. Rev. C 60,
034607 (1999).

RIKEN Accel. Prog. Rep. 39 (2006)

Laser spectroscopy of 10 Be+ in an on-line ion trap
T. Nakamura, M. Wada, K. Okada,∗1 A. Takamine,∗2 Y. Ishida, S. Shiba,∗3 Y. Yamazaki, T. Kambara,
Y. Kanai, T. M. Kojima, Y. Nakai, N. Oshima, A. Yoshida, T. Kubo, S. Ohtani,∗3 K. Noda,∗4 I. Katayama,∗5
G. Jegou, V. Lioubimov,∗6 H. Wollnik,∗7 V. Varentsov,∗8 and H. A. Schuessler∗6
On-line ion trap, laser spectroscopy, 10 Be+ , isotope shift
We have developed an on-line ion trap for storing
unstable nuclear ions extracted from an rf ion guidesystem.1) Recently, we have succeeded in the on-line
trapping of 10 Be+ ions provided by RIPS, and havemeasured the frequency of the 22 P3/2 − 22 S1/2 transition ν010 of laser-cooled 10 Be+ ions by laser spectroscopy. From the measurement, we derived the isotope shift (IS) between 10 Be+ and 9 Be+ . This IS consists of the ﬁeld shift (FS) and the mass shift (MS).
The FS is due to the diﬀerent distributions of the nuclear charge, which has s dominant eﬀect for heavier
ions but is negligible for Be isotopes. The MS also consists of two parts; the normal mass shift (NMS) andthe speciﬁc mass shift (SMS). The NMS is due to the
reduced mass of atomic electrons. For isotopes of mass
MA and MB , the NMS is expressed asδνNMS (B − A) =me (MB − MA ) Aν ,MA (MB + me )(1)

used to calibrate the absolute frequencies by comparison with the iodine atlas.5) Figure 1 shows thelaser-induced ﬂuorescence (LIF) spectra together with
the iodine spectra and the resonance frequencies of
9,10
Be+ . From the observed resonance frequencies withcompensations due to the Zeeman and hfs shifts under an external ﬁeld B = 0.54 mT, we obtain ν010 =957 413.92(54) GHz and ν09 = 957 396.52(50) GHz, andtheir IS δν = 17.40(104) GHz. The NMS is estimatedto δνNMS = 5.83 GHz from Eq. (1), then the SMS isδνSMS = 11.57(104) GHz. Finally, ∆K derived fromthe SMS using Eq. (2) is shown in Table 1 with theoretical results2–4) which are in good agreement within
experimental error. This result is helpful when we set
laser frequencies for other isotopes, such as 7 Be+ and11
Be+ , which are our main objects to perform precise
hyperﬁne structure spectroscopy for nuclear structure
study.

where me is the electron mass and ν A is the transition
frequency of the isotope of mass mA . The SMS is dueto the mass polarization eﬀect. It can be described by11∆νSMS (B−A) =−∆K,(2)
MA + meMB + mewhere ∆K is the diﬀerence in mass polarization parameter K between the states, and K is deﬁned by the
momentum of the k-th electron pk of the N electron
system asK=Npi · pj  .

(3)

i>j

Some theoretical calculations of the mass polarization
parameter for Be+ have been reported.2–4)
In the experiment, a laser system was used that
contained of a cw tunable ring dye laser (Coherent:
899-21) with a cw SHG unit (Coherent: MBD-200).
The frequency of the dye laser was monitored by awavelength meter (Advantest: TQ8325) and by themagnitude of the iodine absorption signal. Both were
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8

Department of Physics, Sophia University
Graduate School of Art and Science, University of Tokyo
Institute for Laser Science, University of Electro-Communications
National Institute for Radiological Science
High Energy Accelerator Research Organization (KEK)
Department of Physics, Texas A&M University, USA
II. Physikalisches Institute, Giessen University, Germany
Kholopin Radium Institute, Russia

Fig. 1. Experimental results.
Table 1. Comparison between present and theoretical∆K’s. Deviations were compared with the experimental error σ.
Reference
present result∆K [au]0.289(26)

Prasad et al. (1966)2)

0.3296

1.6σ

Chung et al. (1991, 1993)3)

0.28810.03σ0.2852604

0.14σ

Yamanaka (1998)4)

deviation−

References
1) A. Takamine et al.: Rev. Sci. Instrum. 76, 103503(2005).
2) S. S. Prasad et al.: Proc. Phys. Soc. 87, 159 (1966).
3) K. T. Chung: Phys. Rev. A 44, 5421 (1991); K. T.
Chung and X.-W. Zhu: Physica Scr. 48, 292 (1993).
4) N. Yamanaka: Phys. Lett. A 243, 132 (1998).
5) H. Kato et al.: Doppler-Free High Resolution Spectral
Atlas of Iodine Molecule 15000 to 19000 cm−1 (Japan
Society for the Promotion of Science, Tokyo, 2000).

41RIKEN Accel. Prog. Rep. 39 (2006)

6

He+6 He cluster states in 12 Be via α-inelastic scattering

A. Saito,∗1 S. Shimoura,∗1 T. Minemura,∗2 Y. U. Matsuyama,∗3 H. Baba, H. Akiyoshi, N. Aoi, T. Gomi,∗4
Y. Higurashi, K. Ieki,∗3 N. Imai,∗2 N. Iwasa,∗5 H. Iwasaki,∗6 S. Kanno,∗3 S. Kubono,∗1 M. Kunibu,∗3
S. Michimasa, T. Motobayashi, T. Nakamura,∗7 H. Sakurai, M. Serata,∗3 E. Takeshita,∗3 S. Takeuchi,
T. Teranishi,∗8 K. Ue,∗6 K. Yamada, and Y. Yanagisawa
Nuclear reactions, 4 He(12 Be,6 He6 He)
The cluster structure in neutron-rich beryllium isotopes is one of the most interesting phenomena in unstable nuclei. We aimed at searching for excited stateswith low spins, such as 0+ and 2+ , which may lie justabove the 6 He+6 He decay threshold. The α-inelastic
scattering at 60 A MeV based on the inverse kinematics using a liquid helium target1) was used to populate these excited states. The one-step direct-reaction
process is dominant at this energy. In the present
work, the angular correlations between decay particles
are also compared with DWBA predictions. Since thedensity of levels is rather high, the multipole decomposition analysis (MDA) with the DWBA was used.
The details of the experimental setup are described inRef. 2.
The DWBA analyses for α-inelastic scattering were
performed using the computer code TWOFNR.3) A
single-folding model with density-dependent eﬀective
nucleon-α interactions was used in the DWBA calculations.4) The details of the transition densities aredescribed in Ref. 5. The parameters were adjusted
6)
The
to reproduce the 12 Be(α,α )12 Be∗ (2+1 ) reaction.
MDA has been used including angular correlations ofdecay particles as well as the angular distribution of
inelastic scattering. Only even-spin states can be populated since the ﬁnal state is two identical spin-0 particles. The expected maximum angular momentum isassumed to be ∆L = 4 at this energy. Therefore, themultipoles of ∆L = 0, 2, and 4, are included in the
MDA.
Figure 1 shows examples of ﬁts to (a) the angular
distribution of inelastic scattering, and the angular correlation between two 6 He particles with respect to (b)the beam direction and (c) the momentum transfer.
The dashed, dotted, and dash-dotted curves are for∆L = 0, 2, and 4, respectively. The gray dashed, graydotted, and gray dash-dotted curves indicate the contributions of interferences of 0⊗2, 0⊗4, and 2⊗4, respectively. The solid curves show the sum of all contributions, i.e., the coherent sum of the multipoles. These

curves include the experimental resolutions estimatedby Monte Carlo simulations.
Figure 2 shows the excitation energy spectra for multipoles of ∆L=0, 2, and 4 deduced by the MDA. In
Figs. 2 (a) and (b), the peaks indicated by closed arrows are newly observed states for ∆L = 0 and 2,
respectively. For the ∆L = 4 spectrum, the previously
reported levels are indicated with open arrows. No
distinct peaks are observed because of large statisticalerrors.
The lowest 0+ and 2+ states, together with 4+ –8+
levels,7) may form a rotational band with h̄2 /2I =139 keV, which corresponds to a developed 6 He+6 Hecluster structure. By assuming that all rotational
bands have similar moments of inertia, the third lowest
0+ and 2+ states may be connected to the previously
observed 6+ state at 18.6 MeV.7)∗11) H. Ryuto et al.: Nucl. Instrum. Methods Phys. Res. A
555, 1 (2005).
2) A. Saito et al.: RIKEN Accel. Prog. Rep. 37, 48 (2004).
3) M. Igarashi: DWBA code twofnr, unpublished.
4) A. Kolomiets et al.: Phys. Rev. C 61, 34312 (2000).
5) G. R. Satchler et al.: Nucl. Phys. A 472, 215 (1987).
6) S. Shimoura: Nucl. Phys. 738, 162 (2004).
7) M. Freer et al.: Phys. Rev. Lett. 82, 1383 (1999).

∗2
∗3
∗4
∗5
∗6
∗7
∗8

42

Center for Nuclear Study, University of Tokyo
Institute for Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Department of Physics, Rikkyo University
National Institute of Radiological Sciences
Department of Physics, Tohoku University
Department of Physics, University of Tokyo
Department of Physics, Tokyo Institute of Technology
Department of Physics, Kyushu University

Fig. 1. (left) Example of a ﬁt with ∆L = 0, 2, and 4, to(a) the angular distribution of inelastic scattering, andthe angular correlation with respect to (b) the beam
direction and (c) the momentum transfer.
Fig. 2. (right) Decay-energy spectra for (a) ∆L = 0, (b)∆L = 2, and (c) ∆L = 4, for the 4 He(12 Be, 6 He6 He)reaction.

References

RIKEN Accel. Prog. Rep. 39 (2006)

8

Li(α,n)11B reaction measurement using monolithic silicon telescope

S. Nishimura, M. Kurata-Nishimura, H. Fujikawa,∗1 A. Guilherme,∗1 J. J. He,∗1 S. Kubono,∗1 H. Yamaguchi,∗1
T. Teranishi,∗2 Y. Wakabayashi,∗2 S. Bishop, M. Kurokawa, T. Kishida, and T. Motobayashi[Astrophysics, unstable nuclei]
The 8 Li(α,n)11 B reaction has recently been identiﬁed as one of the important reaction paths for passing
through the valley of A = 8 in the synthesis of 12 C
and heavy elements at the early stages of Big Bang.
Similarly, the inclusion of the pathway that involves
the 8 Li(α,n)11 B reaction in r-process nucleosynthesischanges the ﬁnal heavy nuclei abundances according
to full network calculations.1,2)
Various experiments over the past decade haveattempted to determine the cross section of the8Li(α,n)11 B reaction.3–6) However, previous measurements have produced inconsistent results and havebeen unable to study the lowest resonances of interest due to diﬃculties in particle identiﬁcation of lowenergy 11 B ions from the background particles, whichmainly consist of elastically scattered 8 Li ions and α
particles as well as the decay products of 8 Li.
A new approach for exploring the low-energy nuclear
reactions has been investigated on the simulation code
GEANT4.7,8) Our studies show that the application ofa monolithic detector,9) consisting of ﬁve ultrathin silicon pads (∆E) of 1 µm thickness supported by 508-µmthick silicon detector (E), would enable us to measure
the low energy nuclear reactions in the gas target.10)
A ﬁrst attempt of 8 Li(α,n)11 B reaction measurement
using the monolithic silicon detector array was performed in the inverse kinematics at CRIB. The primary beam of 7 Li ions was accelerated up to 24 MeV
and was impinged on a deuteron gas target at F0. 8 Li
nuclei produced via the reaction d(7 Li,p)8 Li were thenmomentum-ﬁltered from the intense 7 Li primary beamby an aperture inserted at the dispersive focal planeat F1. In addition, a Wien ﬁlter in conjunction withthe time-of-ﬂight information among the RF and two
PPACs enabled us to extract pure 8 Li ions at the detector section of F3. The energies of 8 Li ions passing through 7 µm Mylar foil, two tracking detectors(PPACs), and the entrance window of gas cell (2 µm
thick Mylar foil) were decreased to 0.25 ± 0.05 MeV/ucorresponding to the Ecm of ∼ 0.5 MeV. The incident
8
Li beam and reaction products in the 6 cm He gas cellat the gas pressure of 100 Torr were detected by 18 setsof monolithic silicon detectors at the downstream endof the gas target. The intensity of the 8 Li beam wasapproximately 1∼5×103 cps after the gas cell window.
Moreover, the He gas cell was surrounded by an array∗1∗2

Center for Nuclear Study, Graduate School of Science, University of Tokyo
Department of Physics, Kyushu Universityof neutron detectors and γ-ray detectors to measure
any coincident neutrons and the γ rays corresponding
to the decay of excited states in 11 B. Figures 1 (a) and(b) show the preliminary results obtained using themonolithic silicon detectors, where the diﬀerent spectra were obtained between the 4 He gas pressures of 0
and 100 Torr. The large amount of events below 2000
ch corresponds to the incident 8 Li ions directly implanted to the monolithic silicon detectors. The cluster in large ∆E region indicates the reaction productsof 11 B from the 8 Li(α,n)11 B reaction. Our preliminary
results show that the monolithic silicon detector arrayhas suﬃcient capability for eﬃciently identifying the8Li(α,n)11 B reaction even at the Ecm of approximately
0.5 MeV.

Fig. 1. (a) Comparison of ∆E spectrum between empty
target runs and 4 He target runs. (b) Correlation between energy deposited in ∆E and E layers. There areclusters at large ∆E area where the reaction productsof the 11 B are expected from the 8 Li(α,n)11 B reaction.

References
1) M. Terasawa et al.: Astrophys. J. 562, 470 (2001).
2) T. Kajino et al.: Nucl. Phys. A 704, 165c (2002).
3) X. Gu et al.: Phys. Lett. B 343, 31 (1995).
4) R. N. Boyd et al.: Phys. Rev. Lett. 68, 1283 (1992).
5) Y. Mizoi et al.: Phys. Rev. C 6206, 5801 (2000).
6) S. Cherubini et al.: Eur. Phys. J. A 20, 355 (2004).
7) M. K-Nishimura et al.: RIKEN Accel. Prog. Rep. 37,
183 (2004).
8) M. K-Nishimura et al.: Nucl. Phys. A 758, 162c
(2005).
9) A. Musumarra et al.: Nucl. Instrum. Methods Phys.
Res. A 409, 414 (1998).
10) S. Nishimura et al.: RIKEN Accel. Prog. Rep. 38, 142(2005).

43

RIKEN Accel. Prog. Rep. 39 (2006)

Elastic scattering and Coulomb dissociation of 8 B on Pb, liquidhydrogen and liquid helium targets
S. Bishop, T. Motobayashi, N. Aoi, H. Baba, T. Gomi, Y. Ichikawa,∗1 N. Imai,∗1 N. Iwasa,∗2 H. Iwasaki,∗1
S. Kawai,∗3 Y. Kondo,∗4 T. Nakamura,∗4 T. Nakao,∗1 S. Nishimura, T. Ohnishi, T. K. Onishi,∗1 H. J. Ong,∗1
S. Ota,∗5,6 A. Perera, S. Shimoura,∗5 T. Sumikama, D. Suzuki,∗1 H. Suzuki,∗1 M. K. Suzuki,∗1 S. Takeuchi,
M. Tamaki,∗5 K. Tanaka, Y. Togano,∗3 and Y. Yanagisawa
8B, elastic scattering, Coulomb dissociation, nuclear astrophysics, S-factor
The solar 7 Be(p, γ)8 B reaction has been the object ofintense experimental and theoretical studies for morethan 30 years. This reaction is responsible for producing the detectable solar neutrino flux.1) An outstanding problem in nuclear astrophysics is the determination of the zero-energy astrophysical S-factor
for the 7 Be(p, γ)8 B reaction. The cross section of the
proton capture on 7 Be can be determined by measuring the dissociation of 8 B in the presence of a known
photon flux provided by the Coulomb field of a target nucleus. Studies of this sort have been previously
performed employing Pb targets; however, such studies have shown that the break-up cross section of 8 B
on Pb, while dominated by E1 electromagnetic interaction, also contains contributions from E2, M1, andperhaps non-negligible nuclear break-up contributions.
Determination of these higher order contributions aredesired to determine the S-factor to a higher degree of
accuracy.
To this end, a Coulomb dissociation experiment of
8
B was performed at the RIKEN RIPS facility using Pb (57 mg/cm2 ), liquid helium (130 mg/cm2 ) andliquid hydrogen (63 mg/cm2 ) secondary targets, positioned at the achromatic focal plane of RIPS. Use of
these three targets will provide the necessary information to disentangle the multipole and nuclear contributions to the 8 B break-up cross section. Productionof the secondary 72 MeV/u 8 B beam was done using a
135 MeV/u primary 12 C beam impinging on a 1.5 mm
thick production target of pure nickel. The 8 B secondary beam intensity was ≈ 150 kcps and had a purity of 76%. The incident 8 B beam momentum, p, wasmade using two PPAC detectors located 1.91 m and1.61 m upstream of the secondary target position; detection of the charged particle reaction products, andtheir momentum and energy, was performed using a
1 × 1 m2 segmented plastic scintillator hodoscope2) positioned 3.86 m downstream of the secondary target
position. The total angular resolution of this detector set-up has been determined as 4.4 mrad. Gammaray detection for break-up into the first excited state
∗1
∗2
∗3
∗4
∗5
∗6

44

Department of Physics, University of Tokyo
Department of Physics, Tohoku University
Department of Physics, Rikkyo University
Department of Physics, Tokyo Institute of Technology
Center for Nuclear Study, University of Tokyo
Department of Physics, Kyoto Universityof 7 Be was performed using the γ-ray detector array
DALI2.3)
The break-up data will be analyzed using a
distorted-wave theory, combined with a GEANT
Monte Carlo code which simulates the incident beamemittance, the angular resolution of the PPACs, theresponse functions of all 132 DALI2 detectors, and thetiming and position responses of the 29 hodoscope scintillator bars. From the analysis of 8 B elastic scattering
angular distributions, constraints on a phenominological optical potential, or a microscopically constructed
potential, such as a double-folding model, will be obtained.
Presently, preliminary 8 B elastic scattering angular
distributions have been extracted from the data andare shown in Fig. 1. These distributions are now being
analyzed, as a first attempt, within the framework of
the Woods-Saxon optical potential formalism. Comparison between theoretical and experimental elastic
angular distributions will determine optical parameters for the aforementioned constraints. Additionally,
this analysis will test the extendability, into a much
lower mass and energy range, of the energy, proton
number and neutron number, dependence of the optical potential parameters previously determined inbroader global studies4,5) of proton elastic scattering
data.

Fig. 1. 8 B elastic scattering angular distributions for Pb(left), liquid helium (centre) and liquid hydrogen (right)
targets.

References
1) J. N. Bahcall: Phys. Rev. 135, B137 (1964).
2) I. Hisanaga et al.: RIKEN Accel. Prog. Rep. 31, 162(1998).
3) S. Takeuchi et al.: RIKEN Accel. Prog. Rep. 36, 148(2003).
4) R. L. Varner et al.: Phys. Rep. 201, 57 (1991).
5) F. D. Becchetti, Jr. and G. W. Greenlees: Phys. Rev.
182, 1190 (1969).

RIKEN Accel. Prog. Rep. 39 (2006)

Proton inelastic scattering of 14 Be
Y. Kondo,∗1 T. Nakamura,∗1 Y. Satou,∗1 T. Sugimoto,∗1 N. Matsui,∗1 Y. Hashimoto,∗1 T. Okumura,∗1
T. Nakabayashi,∗1 M. Shinohara,∗1 N. Aoi, N. Endo,∗2 N. Fukuda, T. Gomi, S. Kawai,∗3 M. Kitayama,∗2
T. Kobayashi,∗2 Y. Matsuda,∗2 T. Motobayashi, T. K. Onishi,∗4 H. J. Ong,∗4 H. Otsu, H. Sakurai,
S. Shimoura,∗5 S. Takeuchi, M. Tamaki,∗5 Y. Togano,∗3 Y. Yanagisawa, and M. Ishihara
Nuclear reactions: 14 Be+p, proton inelastic scattering, invariant mass method
We have studied the proton inelastic scattering of
the neutron-rich nucleus 14 Be using a liquid hydrogentarget. Disappearance of the magic number N = 8
in 12 Be has been revealed from the systematics of theexcitation energy of the 2+ state in even-even beryllium isotopes. A large quadrupole deformation length
has been also obtained for 12 Be from the inelastic+
cross section of the 0+transition on a prog.s. → 2
1)
ton target. Information regarding the 2+ state in
the neighboring nucleus 14 Be is important to understand the shell-closure melting at N = 8. Recently,
the ﬁrst 2+ state above the two-neutron separation energy S2n = 1.34 MeV2) in 14 Be has been observed at
1.67 MeV in a breakup reaction on a carbon target.3)
This energy is smaller than that of 12 Be. The mechanism for lowering the 2+ level compared with 12 Be is
not well understood yet.
In the present study, we aim at investigating the deformation and shell structure of 14 Be by studying proton inelastic scattering. Since the proton and carbon
targets have diﬀerent sensitivities to the protons andneutrons in the 14 Be nucleus, the proton and neutrontransition quadrupole matrix elements Mp and Mn canbe deduced independently by comparing the deformation lengths obtained from the inelastic cross sections
using the proton and carbon targets.4) In addition,other excited states can be observed in this experimentbecause the proton target, which has an isovector component, is more accessible to various states than the
carbon target, which is an isoscalar probe.
Since no bound excited states exist in 14 Be, we needto measure the states in the continuum region. Here,
we adopt the invariant mass method to investigate theunbound excited states with a kinematically complete
measurement in proton inelastic scattering. In this reaction, 14 Be is broken up by the proton target into 12 Be
and two neutrons because 13 Be has no bound states.
By measuring the momentum vectors of the breakup
fragments, the relative energy of 12 Be+2n can be deduced via the invariant mass method.
The experiment was performed at the in-ﬂight
radioactive-isotope beam separator, RIPS.5) A primary 18 O beam at 100 MeV/nucleon bombarded a Be
∗1
∗2
∗3
∗4
∗5

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

target with 6 mm thickness to produce a secondary
14
Be beam. Particle identiﬁcation of the secondary
beam was carried out event-by-event using the time-ofﬂight (TOF) information between a cyclotron RF anda 1-mm-thick plastic scintillator placed at the second
focal point of RIPS. The 14 Be ion bombarded a liquidhydrogen target with a thickness of 228 mg/cm2 . Theenergy of the 14 Be beam at the center of the liquidhydrogen target was 69 MeV/nucleon. The incident
angle of the 14 Be beam was measured by two sets ofparallel-plate avalanche counters6) placed upstream ofthe liquid hydrogen target.
The neutrons were detected by a six-layered neutron
hodoscope array (NEUT), which consists of 56 bars
with dimensions of 6 cm × 6 cm × 2.1 m and 30 barsof 6 cm × 6 cm × 1.1 m. The front side of NEUT was
equipped with a thin layer of plastic scintillators to reject the charged particle background. The momentum
vectors of the neutrons were reconstructed from the hit
position and TOF.
The 12 Be fragment emitted in the breakup reaction
was bent by a large-gap dipole magnet, was detected
and traced by two multi wire drift chambers located at
the entrance and exit of the magnet, and penetrated ahodoscope (HOD), which consists of seven plastic scintillator slats of 1 cm thickness. Particle identiﬁcation of
the breakup charged fragment was performed by combining the ∆E and TOF information from HOD withthe magnetic rigidity information obtained from thetrace. The momentum vector of the charged fragment
was deduced from the TOF and trace.
Forty-eight blocks of NaI(Tl) scintillators surrounding the liquid hydrogen target were used to examine
whether 12 Be is in the excited state by detecting deexcitation γ rays. Each scintillator crystal has a size of
6 cm × 6 cm × 12 cm. Data analysis is now in progress.
References
1) H. Iwasaki et. al.: Phys. Lett. B 481, 7 (2000).
2) G. Audi and A. H. Wapstra: Nucl. Phys. A 565, 66(1993).
3) T. Sugimoto et. al.: private communication.
4) A. M. Bernstien, V. R. Brown, and V. A. Madsen: Comments Nucl. Part. Phys. 11, 203 (1983).
5) T. Kubo et. al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
6) H. Kumagai et. al.: Nucl. Instrum. Methods Phys. Res.
A 470, 562 (2001).

45

RIKEN Accel. Prog. Rep. 39 (2006)

Invariant-mass spectroscopy of 14 Be
T. Sugimoto,∗1 T. Nakamura,∗1 N. Fukuda, M. Miura,∗1 Y. Kondo,∗1 N. Aoi, H. Baba, D. Bazin,∗2 T. Gomi,
H. Hasegawa,∗3 Y. Hashimoto,∗1 N. Imai,∗4 T. Kobayashi,∗5 T. Kubo, T. Motobayashi, A. Saito,∗6
H. Sakurai, S. Shimoura,∗6 A. M. Vinodkumar,∗7 K. Watanabe,∗5 Y. X. Watanabe,∗4 T. Yakushiji,∗5
Y. Yanagisawa, K. Yoneda, and M. Ishihara
Nuclear reactions: C(14 Be, 12 Be 2n), nuclear breakup
Recently, shell quenching at N = 8 in 12 Be has beensuggested by experimental investigations of the lowlying ﬁrst 2+ state and intruder ﬁrst 1− state.1–4) To
discuss the change in the shell stability of beryllium
isotopes, systematic studies of these excited states areimportant. As for the most neutron-rich beryllium isotope 14 Be, although the location of the ﬁrst 2+ state isa key to understand the shell stability, bound excitedstates in 14 Be have never been found. In the present
study, we aim at observing the ﬁrst 2+ state of 14 Be
in the particle-unbound region to discuss the shell stability and deformation property of this nucleus.
The experiment was performed at the RIPS beamline of the RIKEN Accelerator Research Facility. The
secondary 14 Be beam was produced by the projectile
fragmentation from 18 O at 100 A MeV. A carbon target was used to excite 14 Be to a discrete state. The
excited 14 Be broke up into 12 Be + n + n. By measuring
the four momenta of the outgoing 12 Be and neutrons,
decay energy was extracted from the reconstructed invariant mass, and angular distribution was obtained.
Details of the experimental setup are described in theprevious report.5)
Figure 1 shows the decay-energy spectrum of the12
Be + n + n system. A narrow peak at approximately
0.3 MeV was clearly observed. The spectrum was ﬁtted with a Breit-Wigner shape corresponding to thepeak and quasi-free scattering shape as background.
Since the daughter nucleus 12 Be has excited states, itis necessary to identify the ﬁnal state of 12 Be by examining the γ-ray spectrum. Since the cross section measured in coincidence with γ-ray emission was found tobe the order of 10−3 times that without γ-ray emission, the peak in the decay-energy spectrum should be
associated with the ground state of 12 Be. Thus, theobserved peak at Ed = 0.3 MeV is assigned to be theﬁrst excited state of 14 Be, with the excitation energy
extracted from Ed as Eex = 1.56 ± 0.15 MeV (preliminary).
The spin of the ﬁrst excited state can be deter∗1
∗2
∗3
∗4
∗5
∗6
∗7

46

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

Fig. 1. Decay-energy spectrum of 12 Be + n + n system.
The spectrum was ﬁtted with the Breit-Wigner shape(dashed curve) and quasi-free scattering shape (dotdashed curve). The inset shows the angular distribution of the inelastically scattered 12 Be + n + n system.
The solid line shows the theoretical calculation assuming ∆L = 2.

mined from the angular distribution of the inelastically scattered 12 Be + n + n system as shown in theinset of Fig. 1. The distribution is compared with thedistorted-wave coupled-channel calculation using the
ECIS97 code with the optical potential parameters obtained in the 11 Be + 12 C reaction at 47 A MeV.6) The
transferred angular momentum ∆L = 2 is consistent
with the experimental data, and we thus assigned J π ofthe observed peak as 2+ . Compared with the cross section associated with the peak, the deformation length
was extracted as δ = 1.44 ± 0.16 fm (preliminary).
A shell-model calculation analysis was also performed. The excitation energy was well reproduced(Eex = 1.48 MeV) using a eﬀective interaction proposed in Ref. 7, while the deformation length was not
reproduced. Further analysis to discuss the shell stability and deformation property of beryllium isotopes
is now in progress.
References
1) F. Ajzenberg-Selove: Nucl. Phys. A 506, 1 (1990).
2) A. Navin et al.: Phys. Rev. Lett. 85, 266 (2000).
3) H. Iwasaki et al.: Phys. Lett. B 481, 7 (2000).
4) H. Iwasaki et al.: Phys. Lett. B 491, 8 (2000).
5) T. Sugimoto et al.: RIKEN Accel. Prog. Rep. 37, 59(2004).
6) M. Takashina et al.: Phys. Rev. C 67, 037601 (2003).
7) T. Suzuki et al.: Phys. Rev. C 67, 044302 (2003).

RIKEN Accel. Prog. Rep. 39 (2006)

Isoscalar monopole and dipole strengths in 14 O
H. Baba, 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,∗3 N. Iwasa,∗4 H. Iwasaki,∗5 S. Kanno,∗2 S. Kubono,∗1 M. Kunibu,∗2
S. Michimasa, T. Motobayashi, T. Nakamura,∗6 H. Sakurai, M. Serata,∗2 E. Takeshita,∗2 S. Takeuchi,
T. Teranishi,∗7 K. Ue,∗4 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 secondary reactionsin inverse kinematics. As a probe for excitation, inelastic α scattering is useful for exciting isoscalar statesand is the best tool for investigating isoscalar monopoleand dipole excitations. They are compressional excitations called the “breathing mode” and the “squeezingmode”, respectively, and are relevant to the incompressibility of nuclear matter. For light stable nuclei,
isoscalar multipole strength has been studied1,2) using 60 A MeV α and discussed with regard to compressional responses. To start studies of isoscalar compressional responses in unstable nuclei, we performed anexperiment of inelastic scattering of 60 A MeV α on
the light unstable nucleus 14 O in inverse kinematics.
The experiment was carried out at the RIKEN RIPS
course. A 60 A MeV secondary beam of 14 O was transmitted to a liquid 4 He target of 120 mg/cm2 thickness.
Decay particles were detected in coincidence by a ∆EE1-E2 plastic scintillator hodoscope. In this work, thefollowing decay channels were measured: 14 O∗ → 13 N
+ p, 12 C + p + p, 12 C∗1 + p + p, 10 C + α, and10 ∗C1 + α. Excitation energy and angular distribution
were deduced from the momentum vectors of the decay
products.
To obtain the strength distributions, we carriedout multipole decomposition (MD) analysis3) with the
DWBA calculation. In this work, the DWBA calculation was carried out using the single-folding modelwith a density-dependent nucleon-α interaction. Details are described in Ref. 4. For the measured decay channels, the integrated EWSR values of up to
25.0 MeV deduced from the MD analysis were determined to be as 45±11% and 61±14% of the isoscalarmonopole and dipole EWSRs, respectively. The obtained EWSR fractions, which are shown in Fig. 1,
fragmented in a wide excitation energy range and no
massive resonance peaks were found. The experimental results cannot strictly be compared with results ofother experiments higher than 13.8 MeV excitation en-ergy, because the decay channel of α + α + α + p + p,
which has a 13.8 MeV threshold energy, was not measured in this experiment. Nevertheless, the monopoleand dipole strength distributions of 14 O and the lightstable nuclei of 12 C and 16 O are in some agreement.
Therefore, this fragmented distribution without massive peaks may be common in light nuclei, regardlessstable or unstable.
In Fig. 1, additional monopole and dipole strengths
to the known 0+ and 1− states were identiﬁed at E =6–9 MeV. This energy region corresponds to the boundstates in the mirror nucleus 14 C, where neither 0+ nor
1− state was found, these strengths may come from thecontinuum. Similar low-energy isoscalar monopole anddipole responses have been predicted in the neutron
drip line nucleus 28 O.5,6) In addition to the soft-dipolemode, this low-lying isoscalar compressional response
is a new characteristic transition in unstable nuclei.

Fig. 1. Decomposed EWSR fractions of monopole anddipole responses. The strengths fragmented in a wide
excitation energy range without massive peaks.

References
∗1
∗2
∗3
∗4
∗5
∗6
∗7

Center for Nuclear Study, University of Tokyo
Department of Physics, Rikkyo University
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Department of Physics, Tohoku University
Department of Physics, University of Tokyo
Department of Physics, Tokyo Institute of Technology
Department of Physics, Kyushu University

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) H. Baba et al.: CNS Annu. Rep. 2003, 5 (2004).
5) I. Hamamoto and H. Sagawa: Phys. Rev. C 53, R1492(1996).
6) I. Hamamoto et al.: Phys. Rev. C 57, R1064 (1998).

47

RIKEN Accel. Prog. Rep. 39 (2006)

Decoupling of valence neutrons from core in 17 B†
Zs. Dombrádi,∗1 Z. Elekes,∗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 E. Takeshita,∗2 S. Takeuchi, I. Tanihata,∗7
Y. Togano,∗2 C. Wu, Y. Yamaguchi, Y. Yanagisawa, A. Yoshida, and K. Yoshida
Nuclear structure, unstable nuclei, proton inelastic scattering, 17 B, neutron decoupling
Recently, an extremely large Mn /Mp ∼ 4N/Z ratio
has been observed in 16 C.1) In this nucleus, a neutroneﬀective charge of en = 0.15 was deduced1) and canbe considered as a clear indication of the decoupling of
the valence neutrons from the 14 C core. 17 B is anothernucleus where a signiﬁcant decoupling may take placebecause an anomalous electric quadrupole moment of
its ground state was measured at Q = 38.6 ± 1.5 mb.2)
In order to check this idea by deducing the neutron
deformation, we studied the inelastic scattering of 17 B
in inverse kinematics. In the present experiment, we
employed the technique of in-beam γ-ray spectroscopy,
incorporating inelastic proton scattering and utilizing
a liquid hydrogen target for enhancement of luminosity. The experiment was performed at the RIPS beamline of the RIKEN accelerator research facility (for details see Ref. 3). Figure 1 shows the Doppler-corrected
spectra of γ-rays with and without the secondary liquid hydrogen target. A single peak at 1089 (15) keV
can be seen in the bottom panel (subtraction of top
and middle panels), which corresponds to the transition between the ﬁrst excited state and the groundstate. To derive the quadrupole deformation parameter (β2pp ), a distorted–wave calculation was performed.
In this way, we obtained β2pp = 0.57 ± 0.05. Froma comparison with the previously determined electric
quadrupole moment, we deduced the deformation parameters of the neutron and proton distributions to beβn ∼ 0.6 and βp = 0.36, respectively. By exploiting
this information on the neutron and proton deformations of 17 B, an upper limit on the neutron eﬀective
charge of en < 0.12 has been deduced (for detailed
analysis, see Ref. 3). This value is in a good agreement with the one deduced in Ref. 2 of en ≈ 0.1 and is
4 times smaller than the one characteristic for nuclei
close to the stability in this mass region.

†
∗1
∗2
∗3
∗4
∗5
∗6
∗7

48

Condensed from the article in Phys. Lett. B 621, 81 (2005)
Insitute of Nuclear Research (ATOMKI), Hungary
Rikkyo University
Institut de Physique Nucléaire, FranceEötvös Lóránd University, Hungary
University of Tokyo
Tohoku University
TRIUMF, Canada

Fig. 1. Doppler-corrected spectra of γ-rays emerging fromthe 1 H(17 B,17 B) reaction can be seen in the top panel.
The middle spectrum is taken without the liquid hydrogen, whereas the spectrum in the bottom panel isproduced by subtracting the two spectra.

References
1) Z. Elekes et al.: Phys. Lett. B 586, 34 (2004).
2) H. Ogawa et al.: Phys. Rev. C 67, 064308 (2003).
3) Zs. Dombrádi et al.: Phys. Lett. B 621, 81 (2005).

RIKEN Accel. Prog. Rep. 39 (2006)

Structure of 17 B studied by proton inelastic scattering
M. Shinohara,∗1 T. Nakamura,∗1 Y. Satou,∗1 T. Sugimoto,∗1 Y. Kondo,∗1 N. Matsui,∗1 T. Okumura,∗1
Y. Hashimoto,∗1 T. Nakabayashi,∗1 T. Motobayashi, N. Aoi, N. Fukuda, Y. Yanagisawa, S. Takeuchi,
T. Gomi, T. Kobayashi,∗2 H. Otsu,∗2 Y. Matsuda,∗2 N. Endo,∗2 M. Kitayama,∗2 H. Sakurai, T. K. Onishi,∗3
H. J. Ong,∗3 S. Shimoura,∗4 M. Tamaki,∗4 Y. Togano,∗5 S. Kawai∗5 and M. Ishihara
Nuclear structure, 1 H(17 B,17 B∗ ) reaction, In-beam γ-ray spectroscopy
Recently, diﬀerent matter distributions of protons
and neutrons in the 16 C nucleus have been suggested
experimentally and theoretically.1,2) It is interesting todetermine whether this phenomenon also occurs forneighboring nuclei such as 17 B. In this report, we
present the results of in-beam γ-ray spectroscopy using the 1 H(17 B,17 B∗ ) reaction. In the previous studyof the 12 C(17 B,17 B∗ ) reaction, we observed the ﬁrst excited state at Eex = 1.07(1) MeV, and determined thedeformation length δ C to be 1.20(8) fm.3) The present
work has a diﬀerent sensitivity to protons and neutrons
from that with the 12 C target. Then, we have determined the deformation length with proton target, δ p ,from an angular distribution of the 1 H(17 B,17 B∗ ) reaction cross section. By combining the results of δ p andδ C , the transition matrix elements for protons (Mp )and neutrons (Mn ) are extracted.
The experiment was performed using the RIPS radioactive beam separator at RIKEN. A secondary
beam of 17 B was produced by the fragmentation reaction of a 110 MeV/nucleon primary 22 Ne beam incident on a 6 mm Be target. The secondary beam was
identiﬁed event-by-event using the TOF-∆E method.
The intensity and purity of the 17 B beam were 0.3
kcps and 26%, respectively. The 17 B beam bombarded a 120 mg/cm2 liquid hydrogen target placedat the third focal plane. The average beam energy
was 60 MeV/nucleon in the middle of the target. The
incident position and angle upon the target were measured by two PPACs. The ejectiles were momentumanalyzed using a large-gap dipole magnet equippedwith two drift chambers, and were detected using aplastic scintillator hodoscope.
De-excitation γ rays were detected by the DALI system, which consists of 48 blocks of NaI(Tl) scintillatorsplaced around the liquid hydrogen target. Each scintillator crystal has a rectangular shape with a dimensionof 6 × 6 × 12 cm3 . For 0.662 MeV γ rays from a standard 137 Cs source, the eﬃciency and resolution weretypically 9% and 9% (FWHM), respectively. Figure 1
shows the Doppler-shift corrected γ-ray energy spectrum. We observed a clear peak corresponding to the
decay from the ﬁrst excited state. The hatched area
∗1
∗2
∗3
∗4
∗5

Tokyo Institute of Technology
Tohoku University
University of Tokyo
Center for Nuclear Study, University of Tokyo
Rikkyo University

Fig. 1. Doppler-shift corrected γ-ray energy spectrum in1
H(17 B,17 B∗ ) reaction. The hached area represents the
background. The insert shows the angular distributionof the inelastically scattered 17 B. The solid line is the
DWBA calculation result.

in Fig. 1 shows the background spectrum obtained forthe uncorrelated events with 17 B. The peak energy
was 1.07(1) MeV, which is in agreement with previous
works: 1.07(1) MeV3) and 1.089(15) MeV4) .
The scattering angles of the ejectiles were measured
by the drift chamber placed just downstream of the target. The insert in Fig. 1 shows the angular distributionof the inelastically scattered 17 B. The solid line shows
the result of the DWBA analysis based on the code
ECIS97 with ∆Lπ = 2+ . The experimental data is well
reproduced by assuming the ∆Lπ = 2+ , which is consistent with the result of the previous 12 C(17 B,17 B∗ )reaction measurement. From the angular distribution,
we have determined δ p = 1.22(8) fm. The obtained δ p ,together with δ C , allows us to determine the transition
matrix elements Mp and Mn for the 1 H(17 B,17 B∗ ) reaction. Futhermore, by including the static Q moment
for the ground state of 17 B,5) we expect to improve
the accuracies of Mp and Mn , and to extract the eﬀective charges for protons (ep ) and neutrons (en ) in 17 B.
Detailed analysis is now in progress.
References
1) N. Imai et al.: Phys. Rev. Lett. 92, 062501 (2004).
2) Y. Kanada-En’yo: Phys. Rev. C 71, 014310 (2005).
3) Y. Kondo et al.: Phys. Rev. C 71, 044611 (2005).
4) Zs. Dombrádi et al.: Phys. Lett. B 621, 81 (2005).
5) H. Ogawa et al.: Phys. Rev. C 67, 064308 (2003).

49

RIKEN Accel. Prog. Rep. 39 (2006)

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 E. Takeshita,∗2 S. Takeuchi, I. Tanihata,∗7 Y. Togano,∗2
C. Wu, Y. Yamaguchi, Y. Yanagisawa, A. Yoshida, and K. Yoshida
Nuclear structure, unstable nuclei, proton inelastic scattering, 17,19 C, bound excited states
We have investigated the properties of the bound excited states in 17,19 C nuclei via the (p,p’γ) process ininverse kinematics at intermediate energy. The experiment was carried out at the RIKEN radioactive isotope separator RIPS. The details of the setup can befound in Ref. 1. Here, we focus on the results achieved.
In the Doppler corrected spectrum, two peaks associated with the prompt decays of excited states in 19 C
are found at 72(4) and 197(6) keV. The spectrum of
17
C showed two strong peaks at 210(4) and 331(6) keV
establishing two low-lying excited states for this nucleus. The constructed level schemes and tentatively
assigned spin/parities can be seen in Figs. 1 and 2.
It is shown that the shell model gives a qualitativedescription of the results by predicting two excitedstates below 600 keV indepedent of the eﬀective interFig. 2. Experimental level scheme for 19 C nucleus plotted
together with sdpf,3) psdwbp 4) and psdwbt* 5) theoretical predictions. The arrows indicate the relative γ transition strengths observed in (p,p’) reaction.

Fig. 1. Experimental level scheme for 17 C nucleus plotted
together with sdpf,3) psdwbp 4) and psdwbt* 5) theoretical predictions. The arrows indicate the relative γ transition strengths observed in the 19 C → 17 C two-neutron
removal rection.
†
∗1
∗2
∗3
∗4
∗5
∗6
∗7

50

Condensed from the article in Phys. Lett. B 614, 174 (2005)
Insitute of Nuclear Research, ATOMKI, Hungary
Rikkyo University
Institut de Physique Nucléaire, FranceEötvös Lóránd University, Hungary
University of Tokyo
Tohoku University
TRIUMF, Canada

actions applied. Furthermore, in analyzing the crosssections, a distorted wave calculation was performed
using the ECIS792) code. During the analysis, thestandard collective form factors were used for obtaining the “matter” deformation parameters (β2 ) for thediﬀerent transitions. As a result for 19 C, it can be concluded that having a 1/2+ ground state and the excitedstates of 3/2+ -197(6) keV and 5/2+ -269(8) keV resultin β2 (269 keV) = 0.29 ± 0.03. This relatively small deformation parameter suggests a basically single particle nature for the transition with some collective component. For 17 C, to reproduce the cross sections starting with a 3/2+ ground state, a β2 = 0.52 ± 0.04 isneeded if the excited state has a spin of 5/2. Thissuggests that the 17 C nucleus is strongly deformed.
References
1) Z. Elekes et al.: Phys. Lett. B 614, 174 (2005).
2) J. Raynal: Phys. Rev. C 23, 2571 (1981).
3) R. Fujimoto: Ph.D. Thesis, University of Tokyo (2003).
4) E. K. Warburton et al.: Phys. Rev. C 46, 923 (1992).
5) O. Sorlin et al.: AIP Conf. Proc. 701, 31 (2004).

RIKEN Accel. Prog. Rep. 39 (2006)

Inelastic proton scattering of 19 C
Y. Satou,∗1 T. Nakamura,∗1 N. Fukuda, T. Sugimoto,∗1 Y. Kondo,∗1 N. Matsui,∗1 Y. Hashimoto,∗1
T. Nakabayashi,∗1 T. Okumura,∗1 M. Shinohara,∗1 T. Motobayashi, Y. Yanagisawa, N. Aoi, S. Takeuchi,
T. Gomi, Y. Togano,∗2 S. Kawai,∗2 H. Sakurai, H. J. Ong,∗3 T. K. Onishi,∗3 S. Shimoura,∗4 M. Tamaki,∗4
T. Kobayashi,∗5 H. Otsu,∗5 Y. Matsuda,∗5 N. Endo,∗5 M. Kitayama,∗5 and M. Ishihara[Nuclear reaction, unstable nuclei]
Nucleon-induced inelastic and charge exchange reactions, such as (p, p ) and (p, n) reactions, have been
one of the major tools for studying nuclear structures.
Various combinations of spin, isospin, momentum andenergy transfers are available in such reactions. We
applied the (p, p ) reaction in inverse kinematics to a
structural study of the one-neutron halo nucleus 19 C,
speciﬁcally in search of unbound excited states in thisnucleus. The measurement was carried out by the invariant mass method, where the momentum vectorsof all (or part of) the reaction products are measured
and an invariant mass is constructed from them. Thismethod is well suited for the spectroscopy of halo nuclei, which are often characterized by an extremely low
particle decay threshold.1,2)
A 19 C beam with an energy of 70 MeV/nucleon was
produced using RIPS from a 110 MeV/nucleon 22 Ne
primary beam with an intensity of 100 pnA. The
production target was a 6-mm-thick Be plate; thealuminum energy degrader used had a thickness of
3.03 mm. The typical intensity at F3 was 260 cps at
a momentum setting of ∆P/P = ±3%.
Figure 1 shows the layout of the experiment. A cryogenic hydrogen target was used as experimental target,
the thickness of which (120 mg/cm2 ) was carefully chosen so as not to deteriorate invariant mass resolution,
but to obtain a high counting rate. Outgoing neutrons
were detected by a neutron counter hodoscope, consisting of plastic scintillators with a total volume of 400 l
and located 5 m downstream of the target. Outgoing

charged particles (18 C) were analyzed using a dipole
magnet and detected by a plastic counter hodoscopeassociated with a multiwire drift chamber (FDC3). A
He bag was placed along the charged particle path tominimize multiple Coulomb scattering eﬀects.
In the present experiment, a multiwire drift chamber (MDC), having a sense wire conﬁguration of X-UX’-V-X’-U’-X-V’ and a sensitive area of 190 mm(H) ×
140 mm(V), was installed at the entrance of the dipole
magnet. It was used not only to improve the angular resolution but also to facilitate the mass identiﬁcation of charged particles. A mass resolution ofA/∆A(FWHM) ≈ 60 was attained by exploiting theion optical property of the dipole magnet, given astransfer matrix element, and the track information obtained from both FDC3 and MDC.
Figure 2 shows a preliminary invariant mass spectrum of the 1 H(19 C,18 C + n) reaction obtained in thisexperiment. The eﬀects due to ﬁnite detector acceptance are not corrected. A peak can be clearly seen at
approximately 0.9 MeV despite the background. This
peak was observed for the ﬁrst time in this measurement. Further analysis is in progress to determine J πof this peak, and to clarify structures related to 19 C.

Fig. 2. Invariant mass spectrum observed for the 1 H(19 C,
18
C + n) reaction at 70 MeV/nucleon.

Fig. 1. Layout of experiment.
∗1
∗2
∗3
∗4
∗5

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

References
1) T. Nakamura et al.: Phys. Rev. Lett. 83, 1112 (1999).
2) N. Fukuda et al.: Phys. Rev. C 70, 054606 (2004).

51

RIKEN Accel. Prog. Rep. 39 (2006)

In-beam γ-ray spectroscopy of 19 N and 20 N
T. Okumura,∗1 T. Nakamura,∗1 Y. Satou,∗1 N. Fukuda, T. Sugimoto,∗1 Y. Kondo,∗1 N. Matsui,∗1
Y. Hashimoto,∗1 T. Nakabayashi,∗1 M. Shinohara,∗1 T. Motobayashi, Y. Yanagisawa, N. Aoi, S. Takeuchi,
T. Gomi, Y. Togano,∗2 S. Kawai,∗2 H. Sakurai, H. J. Ong,∗3 T. K. Onishi,∗3 S. Shimoura,∗4 M. Tamaki,∗4
T. Kobayashi,∗5 H. Otsu,∗5 Y. Matsuda,∗5 N. Endo,∗5 M. Kitayama,∗5 and M. Ishihara
Nuclear Reaction: 1 H(21 N,19,20 N∗ )X, γ-ray spectroscopy
We have investigated low-lying excited states of theneutron-rich nitrogen isotopes 19 N and 20 N using inbeam γ-ray spectroscopy applied for the fragmentationof 21 N. Excited states of these neutron-rich nitrogenisotopes have not been well studied yet. In particular,
no excited states have been observed for 20 N. In-beam
γ-ray spectroscopy has been found to be a powerful
method of locating low-lying bound excited states ofsuch nuclei. This is the ﬁrst application of in-beam
γ-ray spectroscopy to the analysis of the neutron-richnitrogen isotopes 19 N and 20 N.
The experiment was performed at the RIKEN
Projectile fragment Separator (RIPS).1) A 6.0-mmthick 9 Be production target was bombarded with a
110 MeV/nucleon 22 Ne beam. We obtained a secondary 21 N beam with an energy of 72 MeV/nucleon,
and an intensity of about 60 cps. The purity of the 21 N
beam was about 3%.
The particle identiﬁcation of the secondary beam
was performed by combining the pulse height of a plastic scintillator at the second focal point (F2PL) and thetime-of-ﬂight (TOF) information obtained from theRF signal of the cyclotron and the timing signal of theF2PL. The position and angle of the incident beam at
the secondary target were measured using two parallelplate avalanche counters (PPACs) placed at the third
focal point. The secondary target was liquid hydrogen (LiqH2 ) with a thickness of 120 mg/cm2 . The deexcitation γ rays from excited states of the projectile
fragments were detected using 48 blocks of NaI(Tl)scintillators surrounding the secondary target. Eachscintillator crystal was 6 × 6 × 12 cm3 .
Outgoing nitrogen isotopes downstream of the secondary target were analyzed using a magnetic spectrometer equipped with two drift chambers (MDC and
FDC3) and plastic scintillators (hodoscope). The particle identiﬁcation of outgoing nitrogen isotopes was
performed by combining ∆E and TOF informationfrom the hodoscope, and magnetic rigidity informationfrom MDC and FDC3.
The upper and lower panels in Fig. 1 show the preliminary Doppler-shift-corrected γ-ray energy spectra
obtained in coincidence with the outgoing 19 N and 20 N
∗1
∗2
∗3
∗4
∗5

52

Fig. 1. Doppler-shift-corrected γ-ray energy spectra for19
N (upper) and 20 N (lower).

from the LiqH2 target, respectively. Peaks are observed at 534 ± 20 keV and 1104 ± 49 keV in the case of19
N, and at 612 ± 21 keV and 850 ± 17 keV in the caseof 20 N. The peaks for 19 N are compared with known
levels, as shown in Fig. 2.2) The observed peaks are
assigned to γ rays coming from 1650 keV to 1110 keV
and from 1110 keV to ground state. Further analysis
to determine of these peaks is now in progress.

Fig. 2. Known levels of 19 N. Possible assignments of observed peaks are shown by dashed arrows.

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

1) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
2) R. B. Firestone et al.: Table of Isotopes

RIKEN Accel. Prog. Rep. 39 (2006)

Study of 22,23 O nuclear structure by 22 O+2 H reaction
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 A. A. Korsheninnikov,∗6 K. Kurita,∗7 M. Kurokawa,
N. Matsui,∗3 T. Motobayashi, T. Nakamura,∗3 T. Nakao,∗5 E. Yu. Nikolskii,∗6 T. K. Ohnishi, T. Okumura,∗3
S. Ota,∗8 A. Perera, A. Saito,∗5 H. Sakurai,∗5 Y. Satou,∗3 D. Sohler,∗1 T. Sumikama, D. Suzuki,∗7 M. Suzuki,∗7
H. Takeda,∗5 S. Takeuchi, Y. Togano,∗7 and Y. Yanagisawa
Nuclear structure, unstable nuclei, transfer reaction, single-particle energies, gamma-ray
spectroscopy
To understand the rapid change in the location of theneutron dripline between O and F species, we investigated the nuclear structure of the neutron–rich 22,23 O
nuclei. Since the details of the experiment can be foundin Ref. 1, here we concentrate on the results. By studying the Doppler–corrected gamma-ray spectrum fromthe 22 O(d,d’) reaction, the excitation cross section for
the first excited state in 22 O has been determined to+be σ(0+1 → 21 ) = 19 ± 3 mb. From distorted wave
analysis, we derived the “matter” deformation lengthδM = 0.77 ± 0.07 fm, which corresponds to a moderate mass deformation of βM = 0.23 ± 0.02. We cancompare this result with the data from the 22 O+197 Au
reaction,2) where the proton deformation (βp ) was derived to be between 0.2 and 0.24. This means that theneutron deformation of 22 O is very close the proton
deformation taking into account the mass deformation
determined in the present study, i.e, the N = 14 subshell closure makes both the proton and neutron distributions nearly spherical in 22 O.
To populate the first excited state in 23 O, which is
expected to be unbound, we studied the neutron transfer reaction 2 H(22 O,23 O)1 H in which the excited 23 O
nucleus decays by emitting a neutron and an 22 O isotope. The two preliminary excitation energy spectra
can be found in Fig. 1. Both of them were produced
by selecting neutrons with their light outputs larger
than 5 MeV of the electron–equivalent energy to cut
the gamma-ray-induced events out, and by requiring
multiplicities M ≤ 4 to eliminate the events causedby cosmic ray radiation. Panel (a) shows a spectrumwith 20 ns ≤ TOF ≤ 58 ns between the secondary target and the neutron detectors, while panel (b) shows aspectrum with 20 ns ≤ TOF ≤ 45 ns focussing on the
low-energy part of the excitation energy spectrum. It isclearly visible that the lowest energy peak is at 4 MeV,
which most probably corresponds to the first excitedstate of 23 O with the d3/2 neutron single–particle na∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8

ture. Furthermore, thorough analyses of the angular
distributions are now in progress to confirm these arguments.

Fig. 1. Excitation energy spectrum of 23 O from 22 O(d,p)
reaction.

References
1) Z. Elekes et al.: RIKEN Accel. Prog. Rep. 38, 50 (2005).
2) P. G. Thirolf et al.: Phys. Lett. B 485, 16 (2000).

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

53

RIKEN Accel. Prog. Rep. 39 (2006)

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, 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, 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∗ ), 4 He(25 Ne,23 F∗ ), singleparticle 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∗ ), the neutron
knockout reaction 4 He(24 F,23 F∗ ), and the two nucleon
knockout reaction 4 He(25 Ne,23 F∗ ).
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 average intensity of the
primary beam was ∼500 particle nA. The primary target was 9 Be with a thickness of 1 mm. The secondary
beam was a cocktail of 22 O, 23 F, 24 F and 25 Ne, andproduced by their projectile fragmentation reaction.
The averaged beam energies of 22 O, 23 F, 24 F and 25 Ne
were 35.0, 41.5, 36.0 and 42.7 MeV/nucleon, and these
intensities were 2×103 , 6×102 , 5×102 and 1×103 cps,
respectively. The secondary beam bombarded a liquid helium target1) of 100 mg/cm2 with havar foil windows. The reaction products were identiﬁed using atelescope consisting of 9 SSDs and 36 NaI(Tl) scintillators.2) The scattering angles of the reaction products
were measured using three PPACs. De-excitation γrays from the reaction products were detected using
150 NaI(Tl) scintillators3) surrounding the secondary
target.
In the analysis, we examined the coincidences ofmultiple γ rays in the above-mentioned reactions andreconstructed the γ-decay scheme in 23 F as shown in
Fig. 1. The 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 to populate these
excited states. In these relative cross sections, one
can observe that the 2268- and 4059-keV states arestrongly populated by the proton transfer reaction, but
hardly populated by the neutron knockout reaction.
This strongly suggests that these states have a proton single-particle nature. Furthermore, the cross sections for these states by α inelastic scattering may indicate that the 2268- and 4059-keV states have proton
single-particle conﬁgurations of s1/2 and d3/2 , respectively. The angular distributions of scattered 23 F ions
∗1
∗2
∗3
∗4
∗5
∗6

54

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. The
level energies with underlines show newly observed excited states in the present experiment. The bars on theright side of excitation energies show the relative crosssections to populate these states.

for these states were consistent with the spin-parity
assignments.
The excitation energies of these proton singleparticle states are compared with the shell-model calculations on the basis of the USD4) and SDPF-M5)
eﬀective interactions. These states are located at
higher energies than the predictions by ∼500 keV,
although other states correspond to the predictions
within 100 keV. This may indicate that the shell gapsof d5/2 -d3/2 and d5/2 -s1/2 in 23 F are wider than thosein stable nuclei.
References
1) H. Ryuto et al.: Nucl. Instrum. Methods Phys. Res. A
555, 1 (2005).
2) M. Tamaki et al.: CNS-REP-59, 76 (2003).
3) S. Takeuchi et al.: RIKEN Accel. Prog. Rep. 36, 148(2003).
4) B. H. Wildenthal et al.: Prog. Part. Nucl. Phys. 11, 5(1984).
5) Y. Utsuno et al.: Phys. Rev. C 64, 011301 (1999).

RIKEN Accel. Prog. Rep. 39 (2006)

Coulomb excitation measurement for 18 Ne with precise angular
distribution
K. Yamada, N. Iwasa,∗1 S. Bishop, Z. Elekes,∗2 J. Gibelin,∗3 M. Hosoi,∗4 K. Ieki,∗5 K. Ishikawa,∗6 H. Iwasaki,∗7
S. Kawai,∗5 Y. Kondo,∗6 S. Kubono,∗8 K. Kurita,∗5 M. Kurokawa, N. Matsui,∗6 T. Minemura,∗9 H. Morikawa,∗5
T. Nakamura,∗6 M. Niikura,∗8 M. Notani,∗10 S. Ota,∗11 A. Saito,∗8 H. Sakurai, S. Shimoura,∗8 K. Sugawara,∗4
T. Sugimoto,∗6 H. Suzuki,∗7 T. Suzuki,∗4 E. Takeshita,∗5 S. Takeuchi, I. Tanihata,∗12 T. Teranishi,∗13
Y. Togano,∗5 K. Yamaguchi,∗5 Y. Yanagisawa, and T. Motobayashi
Nuclear reactions: Pb(18 Ne,18 Neγ), E(18 Ne) = 50 AMeV, Coulomb excitation+
The comparison of B(E2; 0+g.s. → 21 ) in the mir18
18
ror nuclei O and Ne is of interest to understandthe core polarization mechanism and evolution of theshell structure, because each of these isotopes has apair of valence nucleons outside the doubly magic 16 O
core.1) The B(E2) for 18 O is well-known, whereas theone for the unstable nucleus 18 Ne is not. The previous work on intermediate-energy Coulomb excitation
measurement2) reported a B(E2) value that markedly
disagreed with two lifetime measurements.3,4) The
Coulomb excitation measurement has a large ambiguity for the treatment of nuclear excitation components due to the lack of angular distribution data.4)
The present study is aimed at providing Coulomb excitation data with a precise angular distribution to resolve the ambiguity.
A secondary beam of 18 Ne was produced by the projectile fragmentation of a 135 AMeV 24 Mg beam on a
1.35-mm-thick nickel target at RIPS. The 18 Ne beamirradiated a lead target of 226 mg/cm2 thickness witha typical intensity of 800 counts per second. The average energy of the beam was 50 AMeV in the middleof the lead target. The experimental setup is the sameas the one described in Ref. 5.
Figure 1 shows the Doppler-corrected γ-ray spectrum measured in coincidence with inelastically scattered 18 Ne. A single distinct peak can be seen at
1.9 MeV, which corresponds to the 1887 keV γ-ray of+18
Ne. The total photopeak
the 2+
1 → 0g.s. transition ineﬃciency was 12% for 1887 keV photons from the 18 Ne
nucleus in ﬂight with v/c ≈ 0.3. The possible contribution to the photopeak yield given by feeding γ-rays
from the second 2+ excited state should be considered
to derive the proper excitation cross section. By ﬁtting∗1

Department of Physics, Tohoku University
ATOMKI, Hungary∗3 Institute de Physique Nucléaire, Orsay, France∗4 Department of Physics, Saitama University∗5 Department of Physics, Rikkyo University∗6 Department of Physics, Tokyo Institute and Technology∗7 Department of Physics, University of Tokyo∗8 Center for Nuclear Study, University of Tokyo∗9 High Energy Accelerator Research Organization (KEK)∗10 Argonne National Laboratory, USA∗11 Department of Physics, Kyoto University∗12 TRIUMF, Canada∗13 Department of Physics, Kyushu University∗2

Fig. 1. Doppler-corrected γ-ray spectrum obtained for18
Ne inelastically scattered on lead target. The solid
curve indicates the result of peak-fit analysis, where asimulated line shape (dashed curve) and an exponential
background (dotted curve) were taken.

the detector response for corresponding 1.7 MeV γ-rays
to the spectrum (not shown in Fig. 1), the contribution
was evaluated to be 5.5±5.5% for the photopeak yield.
The obtained 18 Ne(Pb, Pb ) cross section consists ofa neutron excitation component and a proton excitation component. To extract the B(E2) of 18 Ne, theneutron excitation component is subtracted, which isderived from the B(E2) of 18 O assuming isospin symmetry. The proton excitation component is further
divided into nuclear excitation and Coulomb excitation, both of which can evidently be decomposed andrelated to B(E2) using DWBA calculation. The re+18
Ne is 180 ± 26 e2 fm4 ,sultant B(E2; 0+g.s. → 21 ) of
which is consistent with the lifetime measurement,4)
indicating that the disagreement may not depend on
the experimental method. Further analysis of the angular distribution is in progress.
References
1) R. Sherr and H. T. Fortune: Phys. Rev. C 58, 3292
(1998).
2) L. A. Riley et al.: Phys. Rev. C 62, 034306 (2000).
3) A. B. McDonald et al.: Nucl. Phys. A 258, 152 (1976).
4) L. A. Riley et al.: Phys. Rev. C 68, 044309 (2003).
5) N. Iwasa et al.: RIKEN Accel. Prog. Rep. 38, 58 (2005).

55

RIKEN Accel. Prog. Rep. 39 (2006)

Search for low-lying dipole strength in the neutron-rich nucleus 26 Ne
J. Gibelin,∗1,∗2,∗3 N. Aoi, H. Baba, D. Beaumel,∗2 Y. Blumenfeld,∗2 Z. Elekes,∗4 N. Frascaria,∗2 N. Fukuda,
T. Gomi,∗5 K. Ishikawa,∗6 Y. Kondo,∗6 T. Kubo, V. Lima,∗2 T. Motobayashi, T. Nakamura,∗6
A. Saito,∗3 Y. Satou,∗6 E. Takeshita,∗3 S. Takeuchi, T. Teranishi,∗7 Y. Togano,∗3
A. M. Vinodkumar,∗6 Y. Yanagisawa, and K. Yoshida
Coulomb excitation, low-lying strength, radioactive beam, 26 Ne
How the Giant Dipole Resonance strength evolves
when going from stable to weakly bound nuclei withan extreme neutron-to-proton ratio is an interestingquestion.1,2) Recent theoretical approaches based onmean ﬁeld calculation predict that in the neutron-richnucleus 26 Ne, almost 5% of the Thomas-Reiche-Kuhn(TRK) energy weighted sum rule is exhausted by astrength centered at approximatly 8 MeV.3) This region of energy is located between the one-neutron andtwo-neutron emission thresholds. To conﬁrm this prediction, we performed the Coulomb excitation of 26 Ne
at intermediate energies on a lead target and used theinvariant mass method to reconstruct B(E1) strength.
A secondary 26 Ne beam was produced through thefragmentation of a 95 A.MeV 40 Ar primary beam
on a 2-mm-thick 9 Be target.
The intensity obtained was ∼5.103 pps with an incident energy of
58 MeV/nucleon and a purity of 80%. It was tracked
with two parallel-plate avalanche counters impinged on
a 230 mg/cm2 nat Pb. The outgoing charged fragments
were measured using a set of telescopes placed 1.2 m
upstream of the target, which consisted of two layers(X and Y) of silicon strip detectors (SSD) and a layerof 3-mm-thick Si(Li) from the charged-particle detector MUST.4) An unambiguous mass and charge identiﬁcation of all projectile-like fragments was achieved
using the E-∆E method. In-beam γ-rays were detectedusing the 4π-γ-detector DALI2.5) The hodoscope forneutron detection was an array of 4 layers of 29 plastic
rods each, placed 3.5 m downstream of the target. Its
total intrinsic eﬃciency for the detection of one 60 MeV
neutron was calculated to be ∼25%. Finally, 29 thinplastic rods were used to cover the front face of thewall in order to veto charged particles as well as toprovide an active beam stopper.
The excitation energy spectrum of 26 Ne for the25
Ne+n decay channel take into account all possible
excited states of 25 Ne.6) Furthermore, the method enables us to deduce the corresponding decay branching ratio. We observed an enhancement of the crosssection at E ∗ ∼ 9 MeV. The analysis of the dif∗1
∗2
∗3
∗4
∗5
∗6
∗7

56

On leave for Lawrence Berkeley National Laboratory, USA
Institut de Physique Nucléaire, France
Department of Physics, Rikkyo University
Department of Physics, Tokyo Institute of Technology
National Institute of Radiological Sciences
ATOMKI, Hungary
Department of Physics, Kyushu University

ferential cross section allowed a multipole decomposition of these states. The result of the ﬁt of this
distribution using ECIS 97 calculation and the hypothesis that the nuclear and Coulomb deformation
lengths are equal is presented in Fig. 1. We deducethat 5.2 ± 2.1% of the TRK is exhausted by our structure centred at E ∗ ∼ 9 MeV, which corresponds to aB(E1) = 0.54 ± 0.18 e2 fm2 , in agreement with Cao
and Ma3) calculations in the framework of QRRPA.
Other models7–9) predict similar results for the existence of a low-lying state. However they are divergent
on the collectivity and the conﬁgurations involved. In
the future, a comparison of our results with calculatedbranching ratios should enable the discrimination between diﬀerent approaches.

Fig. 1. Angular distribution of scattered 26 Ne on leadtarget for excitation energies between one- and twoneutron emission thresholds, fitted with theoretical
L = 1 and L = 2 distributions.

References
1) A. Leistenschneider et al.: Phys. Rev. Lett. 86, 5442
(2001).
2) P. Adrich et al.: Phys. Rev. Lett. 95, 132501 (2005).
3) L.-G. Cao and Z.-Y. Ma: Phys. Rev. C 71, 034305(2005).
4) Y. Blumenfeld et al.: Nucl. Instrum. Methods A 421,
471 (1999).
5) S. Takeuchi et al.: RIKEN Accel. Prog. Rep. 36, 148(2003).
6) J. Gibelin et al.: RIKEN Accel. Prog. Rep. 38, 53(2005).
7) E. Khan et al.: Private communication (2005).
8) S. Péru et al.: Private communication (2005).
9) P. Ring et al.: Private communication (2005).

RIKEN Accel. Prog. Rep. 39 (2006)
26
Measurement of B(E2; 0+ → 2+1 ) value in Ne

J. Gibelin,∗1,∗2,∗3 N. Aoi, H. Baba, D. Beaumel,∗2 Y. Blumenfeld,∗2 Z. Elekes,∗4 N. Frascaria,∗2 N. Fukuda,
T. Gomi, K. Ishikawa,∗5 Y. Kondo,∗5 T. Kubo, V. Lima,∗2 T. Motobayashi, T. Nakamura,∗5 A. Saito,∗3
Y. Satou,∗5 E. Takeshita,∗3 S. Takeuchi, T. Teranishi,∗6 Y. Togano,∗3 A. M. Vinodkumar,∗5
Y. Yanagisawa, and K. Yoshida
Coulomb excitation, B(E2), radioactive beam, 26Ne
We performed the experimental Coulomb excitationof a secondary radioactive beam of 26Ne using the
RIKEN Projectile fragment Separator. This secondary
26
Ne beam was produced by the fragmentation of a
95 A.MeV 40 Ar primary beam on a 2-mm-thick 9 Be
target. The intensity obtained was ∼ 5 × 103 pps withan incident energy of 58 A.MeV and a purity of 80%.
It was tracked with two parallel-plate avalanche counters1) before impinging on a 230 mg/cm2 natPb. The
outgoing charged fragments were measured using a hodoscope placed 1.2 m downstream of the target, which
consisted of two layers (X and Y) of silicon strip detectors (SSD) and a layer of 3-mm-thick Si(Li) fromthe charged-particle detector MUST.2) The unambiguous mass and charge identiﬁcation of all projectile-likefragments were obtained using the E-∆E method. Inbeam γ-rays were detected using the 4π NaI detector
DALI2.3)
We extracted the integrated cross section for the ex26
Ne (68(8) mb) by identifycitation of the 2+
1 state ofing its 2018 keV γ-decay. Using the ECIS 97 code withthe optical parameters of 20Ne at 40 MeV/n impinging
on 208Pb4) and on the basis of the hypothesis that the
L=2
L=2) and the Coulomb (δC) deformation
nuclear (δNlengths are equal, we deduced a B(E2) = 87(13) e2 fm4 ,which reproduces both the integrated excited cross section and the corresponding experimental angular distribution of inelastically scattered 26Ne ions, as shownin Fig. 1.
Our B(E2) value disagrees with the previous valueof B(E2) = 228(41) e2 fm4 reported by Pritychenko etal..5) Note that by using their method, which supposesthat the γ-ray emission cross section is a pure Coulomb
excitation, we extracted a B(E2) = 230(30) e2 fm4 ,which is in excellent agreement with their result. The
corresponding angular distribution is plotted in Fig. 1(dashed line) showing a shape diﬀerent from that obtained in the experiment. The discrepancy in the two
results thus comes from the fact that our ﬁrst method

∗1
∗2
∗3
∗4
∗5
∗6

Fig. 1. Scattering angular distribution for first 2+ excitedstate of 26Ne on lead target compared with ECIS 97
calculation: solid line, for the case in which βN = 0.32
and βC = 0.31; dashed line, results of calculation withpure Coulomb excitation (βn = 0.0). Both provide an
integrated cross section of 68 mb. Note that the deformation lengths are correlated to deformation parameters via the relations δN = βN RN and δC = βC RC
where RN and RC are the nuclear and Coulomb radii,
respectively.

takes into account the nuclear excitation component.
References
1) H. Kumagai et al.: Nucl. Instrum. Methods Phys. Res.
A 470, 562 (2001).
2) Y. Blumenfeld et al.: Nucl. Instrum. Methods Phys.
Res. A 421, 471 (1991).
3) S. Takeuchi et al.: RIKEN Accel. Prog. Rep. 36, 148(2003).
4) T. Suomijärvi et al.: Nucl. Phys. A 491, 314 (1989).
5) B. Pritychenko et al.: Phys. Lett. B 461, 322 (1999).

On leave for Lawrence Berkeley National Laboratory, USA
Institut de Physique Nucléaire, France
Department of Physics, Rikkyo University
Department of Physics, Tokyo Institute of Technology
ATOMKI, Hungary
Department of Physics, Kyushu University

57

RIKEN Accel. Prog. Rep. 39 (2006)

Quadrupole collectivity of 28 Ne
and the boundary of the island of inversion†
H. Iwasaki,∗1 T. Motobayashi, H. Sakurai, K. Yoneda, T. Gomi, N. Aoi, N. Fukuda, Zs. Fülöp,∗2 U. Futakami,∗3
Z. Gacsi,∗2 Y. Higurashi, N. Imai,∗4 N. Iwasa,∗5 T. Kubo, M. Kunibu,∗3 M. Kurokawa, Z. Liu,∗6 T. Minemura,
A. Saito,∗7 M. Serata, S. Shimoura,∗7 S. Takeuchi, Y. X. Watanabe,∗4 K. Yamada, Y. Yanagisawa,
and M. Ishihara
Nuclear reactions: Pb, C(28 Ne,28 Neγ), E(28 Ne)=46A MeV, intermediate-energy Coulomb
excitation, deduced B(E2)+
We report a recent result of B(E2↑) for the 0+
g.s. →21
28
excitation in Ne obtained by intermediate-energy
heavy-ion inelastic scattering in reversed kinematics.1)
As the most neutron-rich even-even isotope along the
N = 18 line, 28 Ne attracts much attention2,3) because of its location close to the ‘island of inversion’
where an enhancement of quadrupole deformation ispossible. A sudden decrease of E(2+1 ) at N = 18
among the neutron-rich Ne isotopes (26 Ne: 2.02 MeV,3)28
Ne: 1.29 MeV,2,3) and 30 Ne: 0.79 MeV4) ) suggeststhat a tendency towards deformation occurs at 28 Ne.
A large B(E2↑) value reported in an earlier study ofintermediate-energy Coulomb excitation2) might imply
large deformation of 28 Ne, however a deﬁnite conclusion cannot be made due to the relatively large experimental uncertainties. Thus, further experimental
eﬀort towards a precise determination of B(E2↑) of28
Ne is called for.
The experiment was performed at the RIPS facility
in RIKEN using the same experimental arrangement
described in Ref. 5. The 28 Ne beam with a typicalintensity of 100 counts per second was produced by
RIPS and was directed onto the reaction target placedat the ﬁnal focal plane of RIPS. Two diﬀerent targetsof 693-mg/cm2 -thick Pb and 339-mg/cm2 -thick C wereused to excite the projectiles. The angle-integrated
28
Ne were obcross sections for the 2+
1 excitation oftained to be 93(13) mb and 36(6) mb, respectively, forthe 28 Ne+Pb and 28 Ne+C inelastic scattering, fromthe measurement of de-excitation γ-rays in coincidencewith the scattered 28 Ne particles. To obtain the reduced E2 transition probability B(E2↑), a distorted
wave calculation was performed using the coupledchannel code ECIS79 in a similar fashion to that used
in Ref. 5. The B(E2↑) value was deduced from the 2+
1
excitation cross section with the lead target, while themeasurement with the carbon target was used to evaluate possible contributions from nuclear excitations.

+2
4
We thus obtained B(E2; 0+g.s. → 21 ) = 132(23) e fm ,2)which is smaller than the previously reported valueof 269(136) e2 fm4 with small overlap of the errors. Unexpectedly, the present result of B(E2↑) turns out tobe even smaller than that of the less neutron-rich isotope 26 Ne (B(E2↑)=228(41) e2 fm4 ),2) which contrasts
sharply to the considerable decrease of E(2+1 ) from
26
Ne to 28 Ne.
One possible scenario related to the suppression ofB(E2↑) for 28 Ne follows from a naive shell-model picture as follows. For isotopes located just on the boundary of the ‘island of inversion’, a delicate interplay between the normal (0h̄ω) and intruder (2h̄ω) conﬁgurations prevails. Away from the island, the 0h̄ω conﬁgurations dominate both the ground state and the 2+
1state, while the 2h̄ω conﬁgurations occur at higher excitation energies. Degeneracy between these two conﬁgurations is gradually promoted near the island of
inversion. Since the 0+ –2+ level spacing in the 2h̄ω
conﬁguration is smaller than that in the 0h̄ω one, conﬁguration mixing ﬁrstly occurs between the two unperturbed 2+ states with the 0h̄ω and 2h̄ω conﬁgura28Ne.2) In thistions, pushing down the 2+
1 energy incircumstance, deformation is promoted mostly in the2+
1 state, while the ground state remains rather spherical. As for the E2 strength, the small overlap between
the ground state and the 2+
1 state may lead to a hin2)
dered B(E2↑) in 28 Ne, despite the lowered E(2+
A
1 ).
34
similar argument has been made for Si, where boththe E(2+1 ) and B(E2↑) values are found to be considerably small with respect to the 0h̄ω shell model
calculations.6) Since both of the 28 Ne and 34 Si nuclei
are located between the regions of the ‘normal’ (26 Ne
and 36 S) and ‘deformed’ (30 Ne and 32 Mg) nuclei, thesuppressed collectivity presently observed in 28 Ne canbe a characteristic feature of nuclei lying on the very
boundary of the island of inversion.

†

1) H. Iwasaki et al.: Phys. Lett. B 620, 118 (2005).
2) B. V. Pritychenko et al.: Phys. Lett. B 461, 322 (1999).
3) F. Azaiez: Nucl. Phys. A 704, 37c (2002).
4) Y. Yanagisawa et al.: Phys. Lett. B 566, 84 (2003).
5) H. Iwasaki et al.: Phys. Lett. B 522, 227 (2001).
6) R. W. Ibbotson et al.: Phys. Rev. Lett. 80, 2081 (1998).

References
∗1
∗2
∗3
∗4
∗5
∗6
∗7

58

Condensed from the article in Phys. Lett. B 620, 118 (2005)
Department of Physics, University of TokyoATOMKI, Hungary
Department of Physics, Rikkyo University
High Energy Accelerator Research Organization (KEK)
Department of Physics, Tohoku University
Institute of Modern Physics, China
Center for Nuclear Study, University of Tokyo

RIKEN Accel. Prog. Rep. 39 (2006)

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,∗10 S. Ota,∗11 A. Saito,∗8 H. Sakurai, S. Shimoura,∗8 K. Sugawara,∗5
T. Sugimoto,∗6 H. Suzuki,∗7 T. Suzuki,∗5 I. Tanihata,∗12 E. Takeshita,∗2 S. Takeuchi, T. Teranishi,∗13
Y. Togano,∗3 K. Yamada, K. Yamaguchi,∗3 Y. Yanagisawa, and T. Motobayashi
Nuclear reactions: Pb(20 Mg,20 Mgγ), E(20 Mg) = 58 A MeV, Coulomb excitation
The energies of the first 2+ states and the reduced
transition probabilities B(E2) of even-even nuclei are
one of the fundamental quantities for studying the collective character of nuclei. We studied the 20 Mg nucleus, which lies near the proton drip line, by measuring the Coulomb excitation in reverse kinematics.
A radioactive 20 Mg beam was produced by RIPS incooperation with the RF deflector1) and bombarded alead target with a thickness of 226 mg/cm2 placed at
the final achromatic focal plane of RIPS. The beamenergy at the center of the target was 58 A MeV. Deexcitation γ rays were measured using an array of 68
NaI(Tl) detectors (DALI)2) surrounding the target incoincidence with scattered 20 Mg measured by 9 siliconcounter telescopes arranged in a 3 × 3 matrix. The
details of the experimental setup were previously described in Ref. 3.
Figure 1 shows the angular distribution of inelastically scattered 20 Mg measured in coincidence with the
gamma line at 1.61 ± 0.06 MeV, which was tentatively+ 3)
The curves inassigned to the transition of 2+
1 → 01 .
the figure represent the results of Monte Carlo simulations based on theoretical  = 2 angular distributions
obtained using a coupled channel code ECIS79. The
experimental angular distribution is well reproduced,
indicating that the assumption of the  = 2 transitionis valid.
In the ECIS79 calculation, optical potential parameters were obtained for the elastic scattering data of
84 A MeV 17 O+Pb(dashed),4) 40 A MeV 20 Ne+Pb(solid),5) and 41 A MeV 40 Ar+Pb(dot-dashed).6) The
coupling potentials were obtained by the collective deformation model with the Coulomb and nuclear deformation parameters β2Cand β2n . β2C is directly relatedto B(E2) as β2C = 4π B(E2)/3ZeR2 , whereas β2n af∗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 and Technology∗7 Department of Physics, University of Tokyo∗8 Center for Nuclear Study, University of Tokyo∗9 High Energy Accelerator Research Organization (KEK)∗10 Argonne National Laboratory, USA∗11 Department of Physics, Kyoto University∗12 TRIUMF, Canada∗13 Department of Physics, Kyushu University∗2

Fig. 1. Angular distributions of scattered 20 Mg in coincidence with gamma line at 1.61 MeV in nat Pb(20 Mg,
20Mgγ) reaction. The curves represent results of Monte
Carlo simulations.

fects the nuclear interaction between 20 Mg and lead.
We adopted the Bernstein method,7) which deduces
β2n from the proton and neutron transition matrix elements Mp and Mn , respectively. Mp is related toB(E2) and hence to β2C . Mn was fixed to be Mp of themirror nuclei 20 O from its known B(E2),8) assuming
charge symmetry. β2C was adjusted to reproduce thecross section.
The preliminary experimental B(E2↑) was deduced
to be 229 ± 24 (exp.) ± 78 (theo.) e2 fm4 . Theoreticalambiguity was estimated by accounting the uncertainties regarding a choice of optical potentials and theassumption for β2n .
References
1) K. Yamada et al.: Nucl. Phys. A 746, 156 (2004).
2) T. Motobayashi et al.: Phys. Lett. B 346, 9 (1995).
3) N. Iwasa et al.: RIKEN Accel. Prog. Rep. 38, 58 (2005).
4) J. Barrette et al.: Phys. Lett. B 209, 182 (1988).
5) T. Suomaijärvi et al.: Nucl. Phys. A 491, 314 (1989).
6) T. Suomaijärvi et al.: Nucl. Phys. A 509, 369 (1990).
7) A. M. Bernstein et al.: Phys. Rev. Lett. 42, 425 (1979).
8) S. Raman et al.: At. Data Nucl. Data Tables 78, 1(2001).

59

RIKEN Accel. Prog. Rep. 39 (2006)

Progress in analyzing proton resonant states in 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. 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]
The nuclear structure of the 22 Mg nucleus has received much interest recently because of its role indetermining relevant astrophysical reaction rates.1,2)
The properties of resonant states above the proton
threshold (Qp =5.508 MeV) have been investigated at
TRIUMF.3–5) On the basis of these studies, the conclusion is that the resonance at Ex =5.714 MeV dominates at nova temperatures and the resonance at
Ex =6.332 MeV dominates above T =1.1 GK. Therefore, we would like to investigate the resonant properties of those high-energy states in 22 Mg. In particular, the resonant states above the α threshold(Qα =8.14 MeV) are relevant to the stellar 18 Ne(α,p)21 Na reaction, which is probably one of the key reactions for the breakout from the hot CNO cycle in X-ray
bursters.2) The excited states around the 8.14 MeV region were investigated previously,6,7) however, the spinparities have not been determined yet. In this work,
the excited states in 22 Mg were scanned from 6.3 to
9.0 MeV by a thick-target method.8) It may provide
useful information for evaluating the reaction rate of
the 18 Ne(α, p)21 Na,2) as well as for studying the nuclear structure in 22 Mg.
The experiment was performed using the CNS
radioactive-ion-beam separator (CRIB).9) The experimental setup was previously reported10) in detail. This
report will only show the recent results.
The center-of-mass energies (Ecm ) were deduced using the elastic scattering kinematics of 21 Na+p withcorrection of the energy loss of particles in the target. The overall energy resolutions (FWHM) of Ecm
at θcm =172◦ (SET1) are approximately 20 keV (atEcm =0.5 MeV) to 45 keV (at Ecm =3.5 MeV). While
those at θcm =146◦ (SET2) are approximately 20 to
70 keV. The systematic errors of Ecm are caused
mainly by the uncertainty of proton energy calibration. In SET1, they are approximately ±12 keV (atEcm =1.0 MeV) to ±20 keV (at Ecm =3.5 MeV) and approximately ±13 keV to ±30 keV in SET2.
The ﬁrst excitation energy in 21 Na is only 0.33 MeV,
and it is impossible to distinguish the inelastic scattering events from elastic ones in this work. Thus, thecontribution from inelastic scattering 21 Na(p, p )21 Na
∗1
∗2
∗3
∗4
∗5
∗6

60

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

was not considered in the report.
Figure 1 shows the center-of-mass diﬀerential crosssections for the 21 Na+p elastic scattering at two angles. Only statistical errors were included in the ﬁgure. The region studied by the TRIUMF group is indicated, where two resonant states at Ex =6.61 and6.81 MeV agree very well with their respective 6.615
and 6.795 MeV states5) within uncertainties. Beyond
that, several resonances were observed, and particularly one or two resonances were observed above theα threshold. Not all resonances were indicated due tothe complexity. The previously observed 7.60 MeV7)
and 8.54 MeV6) states were clearly seen in the ﬁgure.
The spectroscopic information of the 8.54 MeV state
will be very useful for evaluating the rate of 18 Ne(α,p)21 Na reaction.
Later on, the cross-sectional data will be analyzed
by the R-matrix code SAMMY-M6-BETA.11)

Fig. 1. Center-of-mass diﬀerential cross sections for21
Na+p elastic scattering at two diﬀerent angles.

References
1) M. Wiescher and K. Langanke: Z. Phys. A 325, 309(2002).
2) M. Wiescher et al.: J. Phys. G 25, 133 (1999).
3) S. Bishop et al.: Phys. Rev. Lett. 90, 162501 (2003).
4) J. M. D’Auria et al.: Phys. Rev. C 69, 065803 (2004).
5) C. Ruiz et al.: Phys. Rev. C 71, 025802 (2005).
6) A. A. Chen et al.: Phys. Rev. C 63, 065807 (2001).
7) J. A. Caggiano et al.: Phys. Rev. C 66, 015804 (2002).
8) S. Kubono: Nucl. Phys. A 693, 221 (2001).
9) Y. Yanagisawa et al.: Nucl. Instrum. Methods Phys.
Res. A 539, 74 (2005).
10) J. J. He et al.: CNS Annu. Rep. 2003, 34 (2004).
11) N. M. Larson: ORNL/TM-9179/R5, Oak Ridge National Laboratory (2000).

RIKEN Accel. Prog. Rep. 39 (2006)

Measurement of proton transfer reaction 4 He(32 Mg,33 Alγ)
S. Ota,∗1 S. Shimoura,∗2 N. Aoi, E. Takeshita,∗3 S. Takeuchi, H. Suzuki,∗4 H. Baba, T. Fukuchi,∗3 T. Fukui,∗1
Y. Hashimoto,∗5 E. Ideguchi,∗2 K. Ieki,∗3 N. Iwasa,∗6 H. Iwasaki,∗4 S. Kanno,∗3 Y. Kondo,∗5 T. Kubo,
K. Kurita,∗3 T. Minemura, S. Michimasa, T. Motobayashi, T. Murakami,∗1 T. Nakabayashi,∗5
T. Nakamura,∗5 M. Niikura,∗2 T. Okumura,∗5 T. K. Onishi,∗4 H. Sakurai, M. Shinohara,∗5
R. Sugo,∗3 D. Suzuki,∗4 M. K. Suzuki,∗4 M. Tamaki,∗2 K. Tanaka, Y. Togano,∗3
Y. Wakabayashi,∗7 and K. Yamada(α,t) Reaction, 33 Al, liquid helium, GRAPE, STQ
A picture of the evolution of the shell structure is
being obtained on the basis of the experimental result about the magicity loss in the N = 8, 20 neutronrich nuclei. The shell structure formed by the meanﬁeld depends on the nuclear deformation, the isospin of
the nuclei, or the occupation number of single-particle
orbits. Systematic studies on single-particle states
as functions of the number of protons and neutrons
provide information on the change in shell structure.
Among N = 20 nuclei, 32 Mg is known to be well deformed1) while 34 Si is believed to be spherical in its
ground state. The property of the ground state in the33
Al nucleus has been studied via beta decay measurement and the decay of 33 Al is described well by an sd shell model calculation.2) In an other experiment, thecandidate 2p2h state is found at an energy of 730 keV
consistent with the shell model prediction.3) These two
diﬀerent experiments suggest that those two states in
33
Al may be normally spherical. However, the shellstructure in other excited states is not clear since thesingle-particle orbits may reﬂect the deformed meanﬁeld provided by the 32 Mg core. In the present study,
we aim at clarifying the shell structure of 33 Al by ﬁnding new excited states and assigning their spins, parities and spectroscopic factors through a measurementof 4 He(32 Mg,33 Alγ) reaction.
The experiment was performed at the RIKEN Accelerator Facility with the RIKEN Projectile fragment
Separator (RIPS).4) A 32 Mg beam was produced byprojectile fragmentation of 40 Ar at 63 MeV/nucleon
bombarding 1-mm-thick carbon and separated by
RIPS. The 32 Mg beam was contaminated with otherneutron-rich isotopes such as 33,34 Al and 35,36 Si. These
isotopes were identiﬁed event-by-event based on theinformation of the time-of-ﬂight between two plastic scintillators of 0.1 mm thickness, at positions F2
and F3, and energy loss in a Si detector of 100 µm
thickness. The energy of the 32 Mg beam at F3 was
40 ± 2 MeV/nucleon. The 32 Mg beam bombarded the
∗1
∗2
∗3
∗4
∗5
∗6
∗7

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

liquid-helium target,5) whose thickness was estimatedto be approximately 150 mg/cm2 from the velocity difference of outgoing particles between the case with helium and the case without it. Gamma rays emitted
from the in-ﬂight 33 Al were detected by Gamma-Ray
detector Array with Position and Energy sensitivity(GRAPE)6) surrounding the target. This consists of 17
pairs of segmented planar germanium detectors. Three
PPACs7) were placed upstream of the target for monitoring incident particles and two PPACs were placeddownstream for outgoing particles, which provide theposition information of the reaction point and the scattering angle of outgoing particles. The resolutions of
the position at the reaction point and the scattering
angle were estimated to be approximately 1 mm and2 mrad, respectively. Outgoing particles were identiﬁed event-by-event by the TOF-∆E-E method. The
TOF was obtained from the timing information of twoplastic scintillators of 300 µm thickness placed downstream of the target with a 3.8 m ﬂight length. We
had a new focus (F4) after the liquid-helium target bySuper conducting Triplet Quadrupole (STQ)8) magnets to strike a balance between the long ﬂight pathand the small array of particle detectors. For the ∆Eand E-detectors, 2 × 2 matrix Si detectors of 100 µm
thickness were located after the STQ magnets with a
10 × 10 cm2 active area, and 6 × 6 matrix NaI(Tl) detectors9) of 50 mm thickness were located after the Si
detectors with a 21 × 21 cm2 active area, respectively.
Data analysis is in progress.
References
1) T. Motobayashi et al.: Phys. Lett. B 346, 9 (1995).
2) A. C. Morton et al.: Phys. Lett. B 544, 274 (2002).
3) W. Mittig et al.: Eur. Phys. J. A 15, 157 (2002).
4) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
5) H. Ryuto et al.: Nucl. Instrum. Methods Phys. Res. A
555, 1 (2005).
6) S. Shimoura et al.: Nucl. Instrum. Methods Phys. Res.
A 525, 188 (2004).
7) H. Kumagai et al.: Nucl. Instrum. Methods Phys. Res.
A 470, 562 (2001).
8) N. Aoi et al.: RIKEN Accel. Prog. Rep. 38, 176 (2005).
9) M. Niikura et al.: RIKEN Accel. Prog. Rep. 37, 155(2004).

61

RIKEN Accel. Prog. Rep. 39 (2006)

Alpha inelastic scattering on 32 Mg
T. Fukui,∗1 S. Shimoura,∗2 T. Murakami,∗1 S. Ota,∗1 N. Aoi, E. Takeshita,∗3 S. Takeuchi, H. Suzuki,∗4 H. Baba,
T. Fukuchi,∗3 Y. Hashimoto,∗5 E. Ideguchi,∗2 K. Ieki,∗3 N. Iwasa,∗6 H. Iwasaki,∗4 S. Kanno,∗3 Y. Kondo,∗5
T. Kubo, K. Kurita,∗3 S. Michimasa, T. Minemura, T. Motobayashi, T. Nakabayashi,∗5 T. Nakamura,∗5
M. Niikura,∗2 T. K. Ohnishi,∗4 T. Okumura,∗5 H. Sakurai, M. Shinohara,∗5 R. Sugo,∗3 D. Suzuki,∗4
M. K. Suzuki,∗4 M. Tamaki,∗2 K. Tanaka, Y. Togano,∗3 Y. Wakabayashi,∗7 and K. Yamada
Nuclear reactions, 4 He(32 Mg,32 Mg γ), alpha inelastic scattering
We performed high-resolution in-beam γ-spectroscopy of the neutron-rich N = 20 nucleus 32 Mg excitedby an alpha inelastic scattering at 42 MeV/nucleon in
inverse kinematics. As the study of the excited statesin 32 Mg is one of the keys for understanding structuralchange in neutron-rich nuclei having N ∼ 20 (islandof inversion), many studies have been performed andseveral excited states reported in 32 Mg.1–3) However,the spins and parities have not been assigned except
for the ground and ﬁrst excited states.
In the present experiment, we aim at deducing population yield for each excited state and determining its
spin and parity by using the angular distribution of
the measured alpha inelastic scattering. Since some γtransitions may have similar energies, high-resolution
γ spectroscopy is necessary to provide unambiguous
assignments of the transitions. In order to deducetransition energies emitted from a fast-moving particle at high energy resolution, emission angle with respect to the momentum vector of the particle should
be determined at a good resolution. On the basis of
this requirement, we used a Ge detector array named
GRAPE4) having position sensitivity and ﬁve sets oftracking detectors for the γ ray and a charged particle.
The experiment was performed at the RIKEN Accelerator Facility with the RIKEN projectile-fragment
separator (RIPS).5) A secondary beam of 32 Mg was
produced by projectile fragmentation of an 40 Ar primary beam on a carbon target at 63 MeV/nucleon.
The 32 Mg beam at 42 MeV/nucleon was separated
by RIPS and used to bombard a liquid He targetof 150 mg/cm2 thickness. The beam particles wereidentiﬁed using time-of-ﬂight (TOF) and energy-loss(∆E) measured using plastic scintillators located at
the second and third foci of RIPS. The beam wastracked by three sets of parallel-plate avalanche counters (PPACs).6) The ejectile was identiﬁed by the
TOF-∆E-E method. The TOF was measured using
two plastic scintillators located at the entrance andexit of the TOF spectrometer.7) ∆E and E were mea∗1
∗2
∗3
∗4
∗5
∗6
∗7

62

Kyoto University
Center for Nuclear Study, University of Tokyo
Rikkyo University
University of Tokyo
Tokyo Institute of Technology
Touhoku University
Kyushyu University

sured using a detector telescope consisting of 100-µm
Si detectors and NaI(Tl) detectors. The direction of
the ejectile was measured using two sets of PPACs
located downstream of the target. γ rays from theejectiles were detected by the GRAPE consisting of
17 position-sensitive Ge detectors. The Doppler shiftof each event was corrected on the basis of TOF andtracking information of the ejectile and the detection
position of γ rays in the Ge detector deduced by pulseshape analysis (PSA).4)
Figure 1 shows a preliminary Doppler-shiftcorrected spectrum of γ rays from the 4 He(32 Mg,32 Mgγ) reaction. In the present analysis, an energy resolution of 28 keV (FWHM) for the 885-keV transition+32
Mg was achieved with PSA, whereas(2+
1 → 01 ) of
36 keV was obtained without PSA. Careful analysis
taking into account the integral and diﬀerential nonlinearity of ADCs and gain drift throughout the experiment is in progress.

Fig. 1. Doppler-shift-corrected γ-ray energy spectrum of
4
He(32 Mg,32 Mg γ) reaction (a) with and (b) without
pulse shape analysis.

References
1) T. Motobayashi et al.: Phys. Lett. B 346, 9 (1995).
2) G. Klotz et al.: Phys. Rev. C 47, 2502 (1993).
3) F. Azaiez et al.: Eur. Phys. J. A 15, 93 (2002).
4) S. Shimoura: Nucl. Instrum. Methods Phys. Res. A
525, 188 (2004).
5) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
6) H. Kumagai et al.: Nucl. Instrum. Methods Phys. Res.
A 470, 562 (2001).
7) N. Aoi et al.: RIKEN Accel. Prog. Rep. 38, 176 (2005).

RIKEN Accel. Prog. Rep. 39 (2006)

Proton inelastic scattering on 32 Mg and 34 Si
S. Takeuchi, N. Aoi, H. Baba,∗1 T. Fukui,∗2 Y. Hashimoto,∗3 K. Ieki,∗4 N. Imai,∗5 H. Iwasaki,∗6 S. Kanno,∗4
Y. Kondo,∗3 T. Kubo, K. Kurita,∗4 T. Minemura,∗5 T. Motobayashi, T. Nakabayashi,∗3 T. Nakamura,∗3
T. Okumura,∗3 T. K. Onishi,∗6 S. Ota,∗2 H. Sakurai,∗6 S. Shimoura,∗1 R. Sugo,∗4 D. Suzuki,∗6 H. Suzuki,∗6
M. K. Suzuki,∗6 E. Takeshita,∗4 M. Tamaki,∗1 K. Tanaka, Y. Togano,∗4 and K. Yamada[Nuclear structure, in-beam γ-ray spectroscopy]
Proton inelastic scattering was applied to 32 Mg and
Si nuclei located at and around the island of inversion. These nuclei were studied by β-γ spectroscopy
and Coulomb excitation reaction to investigate collective motions or shape coexistence characteristic for theisland of inversion. In these studies, excitation energies of higher states were obtained;1–4) however, thespins and parities of the states other than the 2+ state
are still unknown. In the present study, de-excitation
γ rays from inelastically scattered particles were detected and analyzed by γ-γ analysis to obtain crosssections and spin-parity information.
32
Mg and 34 Si beams were produced by projectile
fragmentation reaction of a 94 MeV/nucleon 40 Ar primary beam with 370 mg/cm2 and 231 mg/cm2 9 Be production targets for 32 Mg and 34 Si, respectively. The
secondary beams were separated using RIPS5) andidentiﬁed event-by-event using ∆E and the time-ofﬂight (TOF) method between F2 and F3 foci using a Si
detector and two plastic scintillators. The energy andintensity were 56 MeV/nucleon and 700 cps for 32 Mg
and 65 MeV/nucleon and 12 kcps for 34 Si.
The secondary beams bombarded the liquid hydrogen target6) with a thickness of 160 mg/cm2 . Inelastically scattered particles were analyzed using the recently developed TOF spectrometer.7) It consists of a
Si detector, NaI(Tl) detectors,8) two plastic scintillators and Superconducting Triplet Quadrupole (STQ)
magnets.9) The obtained mass resolution for Mg and Si
isotopes was around 1.5% in FWHM. With this highmass resolution, contaminations in 32 Mg and 34 Si mass
gates were reduced to as low as 1%. De-excitation γrays were detected using DALI210) which consists of
160 NaI(Tl) crystals surrounding the reaction target.
The typical energy resolution and eﬃciency are respectively 8% and 21% for 1 MeV γ ray emitted from fast
moving particles (β  0.3).
Figure 1 shows the Doppler-corrected γ-ray spectra
for 32 Mg(p,p ) and 34 Si(p,p ). De-excitation γ raysfrom known 2+ states and from other higher states
are clearly observed in γ-ray spectra for both nuclei.
34

∗1
∗2
∗3
∗4
∗5
∗6

Center for Nuclear Study, University of Tokyo
Department of Physics, Kyoto University
Department of Physics, Tokyo Institute of Technology
Department of Physics, Rikkyo University
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)
Department of Physics, University of Tokyo

Fig. 1. Doppler-corrected γ-ray spectra for a) 32 Mg(p,p )32
Mg∗ and b) 34 Si(p,p )34 Si∗ .

The solid curves show the results of ﬁt consisting of
the response functions of DALI2 and an exponential
background shown by dashed curves. Using the ﬁtting
results together with the γ-γ analysis, the level scheme
and cross sections to each state can be determined.
The spin and parity assignments can also be obtainedby γ-γ angular correlation analysis.
References
1) G. Klotz et al.: Phys. Rev. C 47, 2502 (1993).
2) S. Nummela et al.: Phys. Rev. C 63, 044316 (2001).
3) R. W. Ibbotson et al.: Phys. Rev. Lett. 80, 2081
(1998).
4) T. Motobayashi et al.: Phys. Lett. B 346, 9 (1995).
5) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
6) H. Ryuto et al.: Nucl. Instrum. Methods Phys. Res. A
555, 1 (2005).
7) N. Aoi et al.: RIKEN Accel. Prog. Rep. 38, 176 (2005).
8) M. Tamaki et al.: CNS-REP-59, 76 (2003).
9) K. Kusaka et al.: IEEE Trans. Appl. Supercond. 14,
310 (2004).
10) S. Takeuchi et al.: RIKEN Accel. Prog. Rep. 36, 148(2003).

63

RIKEN Accel. Prog. Rep. 39 (2006)

Weak-coupling structure of proton resonances in 23 Al
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, weak-coupling, R-matrix]
In the present work, the proton resonant states in
Al have been investigated by resonant elastic andinelastic scattering of a 22 Mg RI beam on a thick hydrogen target.1) The resonance energies, proton partial
widths and spin parities are determined for several resonant states by an R-matrix analysis of the excitation
functions. The weak-coupling structure of these stateshas been studied.
The experiment was performed using the CNS radioactive ion beam separator (CRIB).2) The experimental details are described in Ref. 3. By analyzing the recoiled-proton energy spectra measured at
diﬀerent angles, a new level scheme of 23 Al is proposed as shown in Fig. 1.4) The 3.00-MeV and 3.95MeV states are newly observed, and the states at
3.14 and 3.26 MeV could correspond to an observed
broad peak at Ex = 3.204 MeV reported in an earlier study with the 24 Mg(7 Li,8 He)23 Al reaction.5) Via
proton emission, the excited state at 3.00 MeV decays
to the ground state in 22 Mg, while the excited states
at 3.14, 3.26 and 3.95 MeV mainly decay to the ﬁrst
excited state (2+ , 1.25 MeV) in 22 Mg.
The measured elastic and inelastic scattering crosssections were analyzed using the R-matrix code
SAMMY-M6-BETA.6,7) Table 1 lists the resonant
properties, energies, spin parities and proton partial
widths to the ground state (Γp ) and to the ﬁrst ex-

23

Table 1. Resonant properties determined in this work.
The widths are for the inelastic channels for the last
three states. The predicted Jnπ indicates the nth levelof the same J π . (widths in keV)
Ex
3.00
3.14
3.26
3.95

2J π

2Jnπ

Γexp
p,(p )

Γcalp,(p )

Coupling

+

3+
2
7+
2
5+
3
7+
3

32(5)
30(20)
30(20)
30(20)

44
6
10
18

0+ ⊗1d3/2
2+ ⊗1d3/2
mixed
2+ ⊗1d3/2(3 )(7+ , 5+ )
(7+ , 5+ )(7+ )cited state (Γp ) in 22 Mg.
The shell-model calculations have been performed
with an OXBASH8) code. The calculations were carried out in a complete model space spsdpf using an
isospin-conserving W BT interaction.9) The calculated
levels are shown in Fig. 1. The calculated energies of
positive-parity states agree very well with those observed in the mirror 23 Ne nucleus, and the calculated
C 2 S factors are also in good agreement with those determined from the (d, p) reaction.7) To study the weakcoupling structure in 23 Al, the spectroscopic factors of
the excited states in the A = 23 nucleus for the singleparticle structure with the A = 22 core in its ground(or the ﬁrst excited) state were calculated. As shownin the last column of Table 1, their main conﬁgurations
can be explained by the weak coupling of a valence proton with the 22 Mg core, in the ground (0+ ) and ﬁrst
excited states (2+ ). These expected coupling schemes
are in good agreement with the experimental observations for the proton decay. In addition, the proton
partial widths were calculated10) as listed in Table 1.
The experimental values are in reasonable agreementwith the calculated ones.
References

Fig. 1. New level scheme of 23 Al constructed in this work.
The calculated levels are shown for comparison.
∗1
∗2
∗3
∗4
∗5
∗6

64

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) S. Kubono: Nucl. Phys. A 693, 221 (2001).
2) Y. Yanagisawa et al.: Nucl. Instrum. Methods Phys.
Res. A 539, 74 (2005).
3) J. J. He et al.: CNS Annu. Rep. 2003, 34 (2004).
4) J. J. He et al.: CNS Annu. Rep. 2004, 3 (2005).
5) J. A. Caggiano et al.: Phys. Rev. C 64, 025802 (2001).
6) N. M. Larson: ORNL/TM-9179/R5, Oak Ridge National Laboratory (2000).
7) J. J. He et al.: Phys. Rev. C, (2005), to be submitted.
8) B. A. Brown et al.: MSU-NSCL report number 1289
(1988).
9) E. K. Warburton et al.: Phys. Rev. C 46, 923 (1992).
10) C. Iliadis: Nucl. Phys. A 618, 166 (1997).

RIKEN Accel. Prog. Rep. 39 (2006)

β-delayed proton and γ-ray spectroscopy of 24 Si
Y. Ichikawa,∗1 T. Kubo, N. Aoi, V. Banerjee,∗2 A. Chakrabarti,∗2 N. Fukuda, H. Iwasaki,∗1 S. Kubono,∗3
T. Motobayashi, T. Nakabayashi,∗4 T. Nakamura,∗4 T. Nakao,∗1 T. Okumura,∗4 H. J. Ong,∗1
T. K. Onishi,∗1 D. Suzuki,∗1 H. Suzuki,∗1 M. K. Suzuki,∗1 T. Teranishi,∗5K. N. Yamada, H. Yamaguchi,∗3 K. Yoneda, and H. Sakurai
β-delayed proton, β-delayed γ, 24 Si
We investigated the β-decay properties of the 24 Si
nucleus, by β-delayed proton and γ-ray spectroscopy.
24
Si with an isospin value of Tz = −2 is a very protonrich nucleus near the drip line. The structure of
proton-rich nuclei provides a useful platform to investigate isospin symmetry, as well as to test the applicability of the eﬀective interaction of the shell model ina proton-rich region. The β decay of very proton-richnuclei is characterized by its large Qβ value in contrast to a small threshold for the proton emission of thedaughter nucleus. It is thus essential to perform measurements that cover not only β-delayed γ decay, butalso β-delayed proton emission, to obtain a complete
β-decay scheme. Here, we report our measurement of
β-delayed protons and γ rays from 24 Si.
The experiment was performed at the RIKEN Projectile Fragment Separator (RIPS) facility. A radioactive beam of 24 Si was produced by the projectile fragmentation of a 100 A MeV 28 Si beam with a 3.0-mmthick Be target. To determine the half-life of 24 Si, apulsed beam was used; the beam-on and beam-oﬀ cycles were chosen to be 500 ms and 500 ms, respectively.
The measurement of β-delayed protons and γ rays
was performed using separate setups. Figure 1 shows aschematic view of the setup for β-delayed proton measurement. Two aluminum foils were set in a chamber,
along the beam line to stop 24 Si beam. Each stopper
foil had a 2.8 µm thickness and was placed at a tilted
angle of 15 degrees with respect to the beam axis. On
both sides of the foils, four sets of proton telescopes
were installed to detect and identify the protons. Eachproton telescope was composed of a gas ∆E and silicon E detectors. The gas detector, which consisted ofthree electrodes, was used to measure the energy loss(∆E) of the protons. Each electrode was made of awire-mesh sheet with dimensions of 50 mm × 50 mm,
the transmission factor was 95%. The center electrodewas used as an anode, while both ends were connectedto the ground. The ∆E detectors was operated at
300 V in the proportional region. The chamber was
ﬁlled with 20 Torr P10 (Ar 90% + CH4 10%) gas. Behind the gas detector, four 450-µm-thick silicon detectors were set to measure the energy (E) of the protons.
To obtain a clean spectrum of the protons, it is necessary to reduce background contributions attributed
to β rays. Using the ∆E and E information from thetelescopes, we could distinguish the protons from theβ rays.
Figure 2 shows the setup for β-delayed γ-ray measurement. A plastic scintillator with a thickness of
10 mm was placed at a tilted angle of 45 degrees withrespect to the beam line. γ rays were detected bya Clover Ge detector, equipped with a BGO active
Compton shield.
In the measurement of β-delayed protons, we succeeded in obtaining ten times larger statistics thanthose obtained in the previous experiment.1) The
branching ratios of the relevant β decay are to be determined with a higher accuracy. In addition, we found anew β branch to the bound excited state in 24 Al by the
β-delayed γ ray measurement. The present data will
enable us to deduce the absolute values of the branching ratios for the β decay of 24 Si, leading to both unbound and bound states in 24 Al. Analysis of the data
is soon to be ﬁnished.

Fig. 1. Setup for β-delayed proton measurement.
∗1
∗2
∗3
∗4
∗5

Department of Physics, University of Tokyo
Variable Energy Cyclotron Centre, India
Center for Nuclear Study, University of Tokyo
Department of Physics, Tokyo Institute of Technology
Department of Physics, Kyushu University

Fig. 2. Setup for β-delayed γ-ray measurement.

Reference
1) V. Banerjee et al.: Phys. Rev. C 63, 024307-1 (2001).

65

RIKEN Accel. Prog. Rep. 39 (2006)

Investigation of stellar reaction rate for 26 Si(p,γ)27 P by Coulomb
dissociation of 27 P
Y. Togano,∗1 T. Gomi,∗2 T. Motobayashi, Y. Ando,∗1 N. Aoi, H. Baba, 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,∗8 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,∗9 S. Ota,∗10 A. Saito,∗8 H. Sakurai, M. Serata,∗1 S. Shimoura,∗8 T. Sugimoto,∗5 E. Takeshita,∗1
S. Takeuchi, K. Ue,∗7 K. Yamada, Y. Yanagisawa, K. Yoneda, and A. Yoshida 208Pb(27 P,p26 Si)208 Pb, Coulomb dissociation, nuclear astrophysics
The stellar 26 Si(p,γ)27 P reaction has been investigated in terms of the Coulomb dissociation of 27 P. Theγ decay widths of low-lying resonant states in 27 P werededuced to investigate the resonant capture reaction
rate.
This reaction is suggested to aﬀect the synthesis of
26
Al, whose 1.8 MeV γ-line distribution, which is emitted by its β decay, in the galaxy1) is observed by satellite telescopes. Since the β decay of 26 Si feeds only theisomeric state of 26 Al, which subsequently β decays
to the ground state of 26 Mg, 26 Si does not contributeto astrophysical γ rays. However, in a high-density
photon bath of an X-ray burst or supernovae, the statistical equilibrium is achieved among low-lying statesin 26 Al2) and consequently, 26 Si causes the 1.8 MeV γ
rays. Therefore, the destruction of 26 Si by proton capture is important in estimating the synthesis of 26 Al
on the basis of the equilibrium.
An experiment was performed at the RIPS beam lineon the RIKEN Accelerator Research Facility. The details of the experimental setup are described in Ref. 3.
The γ decay widths Γγ of the three states with resonance energies of 0.34, 0.72, and 1.15 MeV are extracted from the experimental results. As discussed
in Ref. 4, Γγ for the ﬁrst excited state is experimentally estimated to be (3.7 ± 2.2) × 10−3 eV by assuming the E2/M1 mixing ratio. The widths of the second and third excited states are determined directlyfrom the experimental cross sections alone because
the transitions to the ground state are induced by almost pure E2 transitions. They are determined to be(1.82 ± 0.28) × 10−4 eV and (3.77 ± 0.74) × 10−4 eV,
respectively.
The astrophysical reaction rate of 26 Si(p,γ)27 P was
calculated using the deduced Γγ s. Figure 1 shows the∗1

Rikkyo University
National Institute of Radiological Sciences∗3 ATOMKI, Hungary∗4 High Energy Accelarator Research Organization (KEK)∗5 Tokyo Institute of Technology∗6 Tohoku University∗7 University of Tokyo∗8 Center for Nuclear Study, University of Tokyo∗9 Argonne, USA∗10 Kyoto University∗2

66

Fig. 1. Reaction rate of 26 Si(p,γ)27 P as a function of temperature of stars obtained in the present study.

temperature dependence of the rate. The three solid
curves represent the present estimations of the resonant capture reaction rates through the three states.
The dotted curves show the margins of error. The resonance parameters, except for Γγ of the ﬁrst and second excited states, were adopted from Caggiano et al.5)
The dashed curve represents the direct capture component calculated by Caggiano et al.5) The spins and parities of the states were deduced by assuming that 27 P
has a level structure analogous to that of the mirror
nucleus 27 Mg.6) The resultant reaction rate indicatesthat resonant capture through the ﬁrst excited state of27
P is the dominant process above 0.1 GK, and thosethrough the second and third excited state give negligible contributions.
References
1) R. Diehl et al.: Astron. Astrophys. Suppl. 97, 181(1993).
2) A. Coc et al.: Phys. Rev. C 61, 015801 (1999).
3) Y. Togano et al.: RIKEN Accel. Prog. Rep. 37, 69(2004).
4) Y. Togano et al.: Proc. of Nuclear Physics in Astrophysics II, Debrecen, Hungary, 2005-5 (Springer), to be
published in Eur. Phys. J. A.
5) J. A. Caggiano et al.: Phys. Rev. C 64, 025802 (2001).
6) P. M. Endt: Nucl. Phys. A 521, 1 (1990).

RIKEN Accel. Prog. Rep. 39 (2006)

Measurement of spin and magnetic moment of 23 Al
A. Ozawa,∗1 K. Matsuta,∗2 T. Nagatomo,∗1,∗2 M. Mihara,∗2 K. Yamada, T. Yamaguchi,∗3 T. Ohtsubo,∗4
S. Momota,∗5 T. Izumikawa,∗5,∗6 T. Sumikama, Y. Nakashima,∗2 H. Fujiwara,∗2 S. Kumashiro,∗2
R. Matsumiya,∗2 M. Ota,∗4 D. Shinojima,∗4 H. Tanaka,∗4 T. Yasuno,∗1 S. Nakajima,∗3 T. Suzuki,∗3
K. Yoshida, K. Muranaka,∗3 T. Maemura,∗3 A. Chiba,∗1 Y. Utsuno,∗7 M. Fukuda,∗2 K. Tanaka,
I. Tanihata,∗8 Y. Nojiri,∗5 T. Minamisono,∗2,∗9 J. R. Alonso,∗10 G. F. Krebs,∗10 and J. Symons∗10Nuclear structure: 23 Al, β-NMR method, g-factor
23

Al is one of the potential candidates for the protonhalo nucleus because its proton separation energy isquite small (125 keV). Recently, the large reaction
cross section of 23 Al has been measured although theerror is still large.1) The authors of Ref. 1 analyzed
the measurement data using a Glauber model with asimple core nucleus (22 Mg) and a valence proton (p)conﬁguration. According to their analysis, the density
distribution of 23 Al should have a halo-like long tail.
Because the density of loosely bound s-wave proton
can be extended, it is suggested that the spin and parity (J π ) of 23 Al might be 1/2+ . However, J π of its
mirror partner 23 Ne is 5/2+ . Thus, if the ground-stateJ π of 23 Al is 1/2+ , a proton halo structure can be anticipated but mirror symmetry is broken between thebound ground states of mirror pairs. Magnetic moment allows us to determine J π directly because magnetic moment is largely diﬀerent for diﬀerent spins.
Therefore, we measured the magnetic moment of 23 Al.
The 23 Al nuclei were produced through the projectile fragmentation process. The primary beam of 28 Si
was accelerated up to 135 A MeV using the RIKEN
ring cyclotron. The Be target thickness was 4.0 mm.
Only the fragments ejected at the angle 1.0 ± 0.6 deg
were separated by the fragment separator RIPS. In
the separator, the momentum of the fragments wasanalyzed, and only the fragments with a momentum
2.0 ± 0.5% larger than the central momentum were selected. To sweep the contaminants of 23 Al, an RF deﬂector2) was installed at the achromatic focus F2 of the
RIPS. The selected fragments were slowed down by anenergy degrader and were implanted in a Si catcher of
0.6 mm thickness placed in a strong magnetic ﬁeld H0of 3.0005 ± 0.0006 kOe. The polarization of the 23 Al is
detected by the β-ray asymmetry in the plastic counter
telescope. An RF magnetic ﬁeld H1 of approximately
13 Oe was applied to induce transitions between magnetic sublevels. An NMR spectrum for wide frequency

modulation (FM) of ±500 kHz is shown in the upper
part of Fig. 1. We found the resonance of approximately 3600 kHz. To determine the resonance more
precisely, we performed measurements with a narrow
FM of ±200 kHz. The result of the NMR spectrum isshown in the lower part of Fig. 1.
We performed shell-model calculations (OXBASH)
to assign J π of 23 Al. For 23 Al, our shell-model calculations show g = +3.410 for J π = 1/2+ and g = +1.575
for J π = 5/2+ . The calculated values are indicated by
the arrows in Fig. 1. Here, the nucleon g-factors in thefree space were used for the calculations. The present
experimental g-factor is well reproduced by the shellmodel value for the ground-state J π of 5/2+ as shownin Fig. 1.
The ground-state J π of 23 Al can give the strong
restriction to the possible structure of the nucleus.
Because the proton separation energy of 23 Al is verysmall, a core nucleus and a valence proton (22 Mg+p)
structure can be anticipated. If we assume the 22 Mg+p
structure, J π of 5/2+ allows three cases of conﬁgurations: 1) the ground state of 22 Mg (J π = 0+ ) couples
to the d-wave valence proton; 2) the ﬁrst excited stateof 22 Mg (Ex = 1.25 MeV, J π = 2+ ) couples to the swave valence proton; and 3) the ﬁrst excited state of22
Mg couples to the d-wave valence proton. Our shellmodel calculations show that the conﬁguration of case1) is 71%, that of case 2) is only 0.2% and that of case3) is 23%. Thus, the conﬁguration with the d-wave
valence proton is the most probable for 23 Al.

∗1

University of Tsukuba
Osaka University∗3 Saitama University∗4 Niigata University∗5 Kochi Institute of Technology∗6 Niigata University RI Center∗7 Japan Atomic Energy Research Institute∗8 TRIUMF, Canada∗9 Fukui University Technology∗10 Lawrence Berkeley National Laboratory, USA∗2

Fig. 1. Observed β-NMR spectra.

References
1) X. Z. Cai et al.: Phys. Rev. C 65, 024610 (2002).
2) K. Yamada et al.: Nucl. Phys. A 746, 156c (2004).

67

RIKEN Accel. Prog. Rep. 39 (2006)†
32
Magnetic moments of 30
13 Al17 and 13 Al19
H. Ueno, D. Kameda, G. Kijima,∗1 K. Asahi, A. Yoshimi, H. Miyoshi,∗1 K. Shimada,∗1 G. Kato,∗1 D. Nagae,∗1
S. Emori,∗1 T. Haseyama, H. Watanabe,∗2 and M. Tsukui∗1
Nuclear structure, spin-polarized radioactive beams, β-NMR method, measured groundstate magnetic moments of 30 Al and 32 Al, shell model
Ground-state magnetic moments of 30 Al and 32 Al
were measured by β-ray detected nuclear magnetic
resonance (β-NMR) using radioactive-isotope beams
spin-polarized in the projectile-fragmentation reaction.
A beam of 30 Al (32 Al) was obtained from the fragmentation of 40 Ar projectiles at an energy of E =95 A MeV on a 93 Nb target of 0.13 (0.37) g/cm2 thickness. In order to spin-polarize the 30 Al (32 Al) beam,
the emission angle and outgoing momentum were selected. Thus, fragments emitted at angles θL = 1.3◦ –5.7◦ were accepted by RIPS using a beam swinger installed upstream of the target. A range of momentum
p = 12.4–12.7 GeV/c (12.2–13.0 GeV/c) was selectedby a slit at the momentum-dispersive focal plane F1.
This momentum range corresponds to 1.006–1.026 p0(0.975–1.034 p0 ), where p0 is a peak in the momentum distribution of the 30 Al (32 Al) beam. The spinpolarized fragments are isotope-separated and introduced into the NMR apparatus located at the final
focus.
We employed β-NMR to determine the µ moment.
In this method, β-rays emitted from the implanted
fragments are detected with plastic scintillator telescopes located above and below the stopper. Whenthe polarization P is altered due to the resonant spinreversal, a change appears in the β-ray up/down ratio. Thus, the resonance frequency ν0 is derived fromthe observed peak or dip in the β-NMR spectrum.
From the β-NMR spectra obtained for the groundstates of 30 Al and 32 Al, we have determined the experimental µ moments, |µexp (30 Al)| = 3.010(7) µN
and |µexp (32 Al)| = 1.959(9) µN , for 30 Al and 32 Al,
respectively, where µN is the nuclear magneton. No
diamagnetic-shielding correction was performed for thepresent values, since the reported chemical shift of 27 Al
in α-Al2 O3 1) is negligible compared with the errors
from other sources.
The experimental µ values were compared withshell-model calculations. The theoretical µ moments
calculated with the USD interaction2) are +3.19 µN
and +2.06 µN for 30 Al and 32 Al, respectively, as listed
in Table 1. In both cases, theoretical values are inagreement with the present experimental values within

†
∗1
∗2

68

Condensed from article in Phys. Lett. B 615, 186 (2005)
Department of Physics, Tokyo Institute of Technology
Department of Nuclear Physics, The Australian National
University, Australia

Table 1. Comparison of experimental magnetic moments(µexp ) and shell-model predictions (µSM ) for aluminumisotopes in unit of nuclear magneton. The diﬀerences
are calculated assuming positive signs for the µexp values if the signs are not assigned.

∼6%. Comparison was also carried out with experimental values of other aluminum isotopes.3,4) As listed
in Table 1, they agree well with each other. Thus, no
prominent deviation was observed in all of these aluminum isotopes.
With respect to 32 Al, an isomer state has been foundrecently at an excitation energy of Ex = 956 keV,5)
above the excited state at Ex = 734 keV.5,6) Spin andparity I π = 2+ and 4+ have been assigned to 734 keV
and 956 keV levels, respectively, from the study of theirγ-decay properties. It is pointed out in Ref. 5 that thisordering is unusual and the USD interaction fails to
reproduce it. Since such disagreements between calculations carried out with the USD interaction andexperimental observations are rare, this unusual level
ordering of 32 Al might stem from the presence of the“island of inversion”. In the present study, however,
we found that the USD interaction can reproduce theexperimental ground-state µ moment of 32 Al as well asthat of 30 Al.
References
1) A. J. Woo: Bull. Korean Chem. Soc. 20, 1205 (1999).
2) B. H. Wildenthal: Prog. Part. Nucl. Phys. 11, 5 (1984).
3) D. Borremans et al.: Phys. Lett. B 537, 45 (2002).
4) P. Raghavan: At. Data Nucl. Data Tables 42, 189(1989).
5) M. Robinson et al.: Phys. Rev. C 53, R1465 (1996).
6) G. Klotz et al.: Phys. Rev. C 47, 2502 (1993).

RIKEN Accel. Prog. Rep. 39 (2006)

Precision measurements of magnetic moments of 31 Al and 32 Al
G. Kijima,∗1 H. Ueno, D. Kameda, M. Takemura,∗1 A. Yoshimi, K. Shimada,∗1 D. Nagae,∗1 M. Uchida,∗1
T. Haseyama, T. Arai,∗1 S. Suda,∗1 K. Takase,∗1 T. Inoue,∗1 H. Kawamura,∗2 and K. Asahi
Nuclear structure, 31 Al, 32 Al, β-NMR method, magnetic moment
We aim at studying the borderline of the “islandof inversion”1) through nuclear moment measurements
for neutron-rich Al isotopes. We measured the magnetic moment (µ-moment) of 30 Al and 32 Al by the
β-NMR method using a single-crystal α-Al2 O3 stopper.2) This sample is also useful for measuring electric
quadrupole moments (Q-moments) because the electric ﬁeld gradients at the Al site of the sample havebeen obtained precisely.3,4) Applying the stopper tothe Q-moment measurement for 32 Al, the eqQ interaction term is estimated to be 13 kHz/mb with the crystal of the c-axis parallel to the external static magnetic
ﬁeld. On the other hand, the obtained accuracy forthe µ-moment of 32 Al corresponds to the frequency of±37 kHz at the static magnetic ﬁeld of B0 ∼ 500 mT.
This accuracy is not suﬃcient to determine the Qmoment precisely. In the case of 31 Al,5) the situation
is found to be more severe. It is necessary, therefore,
to precisely obtain the µ-moments of 32 Al and 31 Al
before the Q-moment measurements.
Spin-polarized 32 Al was obtained from the projectile fragmentation of 95 MeV/nucleon 40 Ar projectiles
on a 367 mg/cm2 thick Nb target. The 32 Al fragments ware separated using RIPS. To obtain spinpolarized 32 Al, the emission angle θL = 1.3◦ –5.7◦
and momenta pF = 12.3–13.0 GeV/c were selected.
In the case of 31 Al, a 128 mg/cm2 thick Nb target
was employed and pF = 12.6–13.4 GeV/c were selected. Thus, the polarized fragments of 32 Al were
implanted in a single-crystal Si stopper of 1 mm thickness to which the external static magnetic ﬁeld B0 ∼500 mT was applied. This material is available for precise µ-moment measurement for 31,32 Al because the µmoment of 25 Al (T1/2 = 7.2 sec) was determined to be|µ(25 Al)| = (3.6455 ± 0.012)µN with diamagnetic correction.6) In addition, the Si stopper has an advantage
in that no electric ﬁeld gradient exists. In the β-NMR
measurement, using the adiabatic fast passage method,an oscillating magnetic ﬁeld perpendicular to the B0
direction was applied to the stopper, which was locatedin the air of the experimental hall. We employed thebeam pulsing method with the RF application.
The obtained β-NMR spectra for 32 Al and 31 Al are
shown in Figs. 1 and 2, respectively. In Fig. 1, thelargest β-ray asymmetry change was observed within
the searched frequency region of 7415.5–7447.8 kHz
with 4.1σ deviation, where σ denotes the standard∗1∗2

Fig. 1. β-NMR spectrum for 32 Al. The vertical bars indicate statistical errors, and the horizontal bars indicate
the widths of swept frequency.

Fig. 2. β-NMR spectrum for 31 Al.

deviation of the β-ray counts. Using this frequency
region, the µ-moment of 32 Al was preliminarily determined to be |µ(32 Al)| = (1.947 ± 0.004)µN , where µN
denotes the nuclear magneton. The error of the µmoment was improved to be half of the previous value.
From Fig. 2, the µ-moment of 31 Al was also determined
to be |µ(31 Al)| = (3.818 ± 0.008)µN in the frequency
region of 5816.0–5841.4 kHz where the largest asymmetry change was observed. The precise µ-momentsof 31,32 Al obtained are consistent with those of previous reports2,5) within the errors. Thus, we employed
the obtained µ-moments for the Q-moment measurements of 32 Al and 31 Al as stated earlier.
References
1) E. K. Warburton et al.: Phys. Rev. C 41, 1147 (1990).
2) H. Ueno et al.: Phys. Lett. B 615, 186 (2005).
3) D. Sundholm and J. Olsen: Phys. Rev. Lett. 68, 927(1992).
4) B. Filsinger et al.: J. Magn. Reson. 125, 280 (1997).
5) D. Borremans et al.: Phys. Lett. B 537, 45 (2002).
6) T. Minamisono et al.: Phys. Rev. B 14, 376 (1976).

Department of Physics, Tokyo Institute of Technology
Rikkyo University

69

RIKEN Accel. Prog. Rep. 39 (2006)

Electric quadrupole moments of 32 Al and 31 Al
D. Kameda, H. Ueno, K. Asahi, G. Kijima,∗1 M. Takemura,∗1 M. Uchida,∗1 A. Yoshimi, K. Shimada,∗1
D. Nagae,∗1 T. Arai,∗1 T. Haseyama, K. Takase,∗1 S. Suda,∗1 T. Inoue,∗1
J. Murata,∗2 H. Kawamura,∗2 and Y. Kobayashi[Nuclear structure, spin-polarized RI beam, nuclear moments, β-NMR method]
The static electric qaudrupole moments (Qmoments) of ground-state 32 Al and 31 Al have beenmeasured to study the nuclear deformations aroundthe border of the “island of inversion”.1) In particular,
the Q-moment of 32 Al is interesting in the determination of the northern border of the “island” along theneutron-rich N = 19 isotones.
The spin-polarized 31 Al and 32 Al beams were
produced from the projectile fragmentation of
95 MeV/nucleon 40 Ar17+ projectiles on a Nb target.
The target thickness for 31 Al (32 Al) was 0.13 g/cm2(0.37 g/cm2 ). The separation of these isotopes wasmade using RIPS. To obtain spin-polarized fragments, selections were also made on the emission angle, θ = 1.3◦ –5.7◦ , and the outgoing momentum of the31
Al (32 Al) fragments, p = 12.6–13.4 GeV/c (p = 12.3–
13.0 GeV/c). The polarized fragments were implanted
in a single crystal α-Al2 O3 sample to which the static
magnetic ﬁeld B0 ∼ 500 mT was applied. The experimental setup around the stopper was almost the sameas that in the µ-moment experiment,2) except the angle, θc , between the crystal c-axis and the B0 direction. Speciﬁcally, two types of angle, θc = 90◦ andθc = 0◦ , were employed. The former angle was used
for searching the Q-moment in the initial stage of theexperiment. The latter angle was used for the precise
measurement.
In Fig. 1, the top and the bottom ﬁgures show theresults of the Q-moment search for 32 Al(I π = 1+ ) forθc = 90◦ and θc = 0◦ , respectively. The vertical andhorizontal axes denote the β-ray asymmetry change
and the absolute value of the coupling constant of thequadrupole interaction, respectively. The Q-moment isobtained using the electric ﬁeld gradient at the Al siteof the α-Al2 O3 sample, eq = 70.9(5) × 1019 V/m2 .3,4)
The vertical bars attached to the solid circles denotethe statistics of the β-ray counts. Each horizontal barof the solid circle indicates the Q-moment region which
was searched by applying the RF ﬁeld. Assuming that2e2 qQ2
1
the region from νQ1 (= | e qQh |) to νQ2 (= | h |) was
searched using the θc = 90◦ setup, the frequency of the
RF ﬁeld would be swept in two diﬀerent frequency re3ν3ν3ν3ν
gions, [f0 − 8Q1 : f0 − 8Q2 ] and [f0 + 8Q1 : f0 + 8Q2 ],where f0 denotes the Larmor frequency. In the spectra,
the magnetic resonance was clearly observed around400 kHz in both θc = 90◦ and θc = 0◦ cases. In the bottom ﬁgure, we obtained the β-ray asymmetry changeof 0.68(19)% in the region of 376.5–513.3 kHz whichcorresponds to the Q-moment region of 22–30 mb. The
magnitude of the β-asymmetry change agrees with thatobtained in the magnetic moment measurement.2)
Figure 2 shows the result for 31 Al. We observed
the magnetic resonance in the Q-moment region of 70–
94 mb with the β-asymmetry change of 0.27(8)%. Further Q-moment search is needed for 31 Al.
Although analyses are now in progress, the obtained
Q-moment of 32 Al shows that the shape of 32 Al isspherical. This indicates that 32 Al is located out of
the “island of inversion”.

Fig. 2. Spectrum of Q-moment search for 31 Al holding
crystal c-axis parallel to external static magnetic field.

References
Fig. 1. Spectra of Q-moment measurement for 32 Al.
∗1
∗2

70

Tokyo Institute of Technology
Rikkyo University

1) E. K. Warburton et al.: Phys. Rev. C 41, 1147 (1990).
2) H. Ueno et al.: Phys. Lett. B 615, 186 (2005).
3) D. Sundholm et al.: Phys. Rev. Lett. 68, 927 (1992).
4) B. Filsinger et al.: J. Magn. Reson. 125, 280 (1997).

RIKEN Accel. Prog. Rep. 39 (2006)

Inelastic proton scattering on neutron-rich nuclei 60 Cr and 62 Cr
E. Takeshita,∗1 N. Aoi, S. Ota,∗2 S. Takeuchi, H. Suzuki,∗3 H. Baba,∗4 S. Bishop, T. Fukui,∗2 Y. Hashimoto,∗5
E. Ideguchi,∗4 K. Ieki,∗1 N. Imai,∗6 H. Iwasaki,∗3 S. Kanno,∗1 Y. Kondo,∗5 T. Kubo, K. Kurita,∗1 K. Kusaka,
T. Minemura,∗6 T. Motobayashi, T. Nakabayashi,∗5 T. Nakamura,∗5 T. Nakao,∗3 M. Niikura,∗4 T. Okumura,∗5
H. J. Ong,∗3 T. K. Onishi,∗3 H. Sakurai,∗3 S. Shimoura,∗4 R. Sugo,∗1 D. Suzuki,∗3 M. K. Suzuki,∗3
M. Tamaki,∗4 K. Tanaka, Y. Togano,∗1 and K. Yamada
Nuclear structure, 60,62 Cr(p,p γ), inelastic scattering, unstable nuclei
Inelastic proton scatterings on neutron-rich nuclei
Cr and 62 Cr were studied. The ﬁrst 2+ energies of60
62
24 Cr36 and 24 Cr38 are signiﬁcantly lower than thoseof the neighboring isotopes,1) indicating the narrowering of the N = 40 sub-shell gap. When the N = 40
shell gap is narrowed, a large deformation is expected
for such nuclei in this region, because the locations ofthese nuclei are close to the middle of the neutron pf gshell between N = 28 and 50. The deformation may befurther enhanced by protons, which also favor such deformation because of their location in the middle of the
f7/2 shell between Z = 20 and 28. To study such deformation and collectivity, inelastic proton scatterings ininverse kinematics, H(60 Cr,60 Crγ) and H(62 Cr,62 Crγ),
were performed by γ-ray spectroscopy.
Neutron-rich Cr isotopes were produced by the fragmentation of the 63 MeV/nucleon 70 Zn beam of themean intensity 150 particle nA onto a 9 Be targetof 95 mg/cm2 thickness. These isotopes were separated by the RIKEN Projectile-Fragment Separator(RIPS).2) The intensities of 60 Cr and 62 Cr were 10
cps and 12 cps, respectively. These nuclei bombarded
a liquid hydrogen target3) of 60 mg/cm2 thickness.
De-excitation γ rays from the inelastically scattered
60,62
Cr nuclei were detected by the NaI(Tl) scintillator array DALI24) located around the secondary target. The photo-peak eﬃciency and energy resolution
for the 0.7 MeV γ ray were 26% and 11% (FWHM),
respectively. Scattered particles were identiﬁed usinga TOF-spectrometer5) placed downstream of the secondary target, which is newly developed to improvethe mass resolution of the scattered particles. In thepresent experiment, a maximum mass separation of 2.7
σ was achieved for the scattered particles.
Doppler-corrected γ-ray spectrum obtained in theH(60 Cr,60 Crγ) reaction shown in Fig. 1 (a) exhibits apronounced peak at 650(5) keV. The peak at 210 keV
is associated with 59 Cr, resulting from the contamination in the mass gate of the scattered particles. In
the spectrum obtained in the H(62 Cr,62 Crγ) reaction
shown in Fig. 1 (b), a clear peak is seen at 447(3) keV.
60

∗1
∗2
∗3
∗4
∗5
∗6

Fig. 1. γ-ray spectra obtained in inelastic proton scatterings of 60 Cr(a) and 62 Cr(b).

The energies of γ-ray peaks in 60 Cr and 62 Cr are consistent with the excitation energies of the states tentatively assigned to be the ﬁrst 2+ state in Ref. 1(646(1) keV, 446(1) keV) The determination of the inelastic proton scattering cross sections is in progress.
References
1) O. Sorlin et al.: Eur. Phys. J. A 16, 55 (2003).
2) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
3) H. Ryuto et al.: Nucl. Instrum. Methods Phys. Res. A
555, 1 (2005).
4) S. Takeuchi et al.: RIKEN Accel. Prog. Rep. 36, 148(2003).
5) N. Aoi et al.: RIKEN Accel. Prog. Rep. 38, 176 (2005).

Department of Physics, Rikkyo University
Department of Physics, Kyoto University
Department of Physics, University of Tokyo
Center for Nuclear Study, University of Tokyo
Department of Physics, Tokyo Institute of Technology
High Energy Accelerator Research Organization (KEK)71

RIKEN Accel. Prog. Rep. 39 (2006)

Proton inelastic scattering on 74 Ni
S. Kanno,∗1 N. Aoi, W. F. Mueller,∗2 H. Sakurai,∗2 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,∗2 T. Kubo,
K. Kurita,∗1 T. Motobayashi, T. Nakamura,∗3 H. Suzuki,∗4 S. Takeuchi,
J. R. Terry,∗2 K. Yoneda,∗2 and H. Zwahlen∗2
Nuclear structure, 74 Ni(p,p γ), 104 MeV/u, inelastic scattering, unstable nuclei
A neutron-rich nucleus 74 Ni was studied by proton
inelastic scattering to explore the evolution of magicity
at Z = 28 in a very neutron rich region. Ni isotopes
close to the stability line show rigid magicity, althoughneutron-rich Ni isotopes could loose the magicity due
to their large neutron excess. As a tool for investigating nuclear magicity, the excitation energy of the first+2+
1 state (Ex (21 )) and the cross-section of the inelas+tic scattering to the 2+
1 state are used. Ex (21 )’s are
54
76
known for the Ni isotopes from Ni to Ni. However,inelastic scattering cross-section to the 2+
1 states is obserbed only for Ni isotopes lighter than 68 Ni. In thiswork, the (p,p ) cross-section of very neutron rich Ni
isotope 74 Ni is measured for the first time.
The experiment was performed at National Superconducting Cyclotron Laboratory in Michigan State
University using an S800 spectrograph. A projectile
fragmentation of 86 Kr on 9 Be target was used to produce the 74 Ni beam. The intensity of 74 Ni beam was
typically 0.5 particle/sec. De-excitation γ rays wereobserved instead of recoil protons to identify the final states. The simultaneous counting of γ rays andscattered particles enable us to determine the reaction
channel. Further information about the experimental
setup, detectors and secondary beam is described inRef. 1.

Figure 1 shows the γ-ray spectrum obtained in coincidence with scattered 74 Ni, where a clear peak+corresponding to the 2+
1 → 0g.s. transition was observed. The energy of the peak is determined tobe 1021(21) keV, which is consistent with the value(1024(1) keV) that has recently been obtained in the
β-decay experiment of 74 Co.2)
The Ex (2+1 ) obtained in this work is plotted in Fig. 2
together with the Ex (2+1 )’s of the neighboring Ni iso74
Ni is slightly lower than that
topes. The Ex (2+1 ) ofof 72 Ni. Several theoretical calculations3–5) are also
shown in Fig. 2 for comparison. All the calculations
reproduce the tendency of the observed value. Further
analysis is in progress to deduce the cross-section anddeformation parameter from the γ-ray yield.

Fig. 2. Ex (2+ ) plotted as function of neutron number. The
closed circle is the value obtained in this work; the open
circles are experimental values.2,6–9) Dashed and dotdashed lines indicate shell-model calculations based on
NR783) and S3V4) eﬀective interactions. Solid line indicates QRPA calculation5) with SkM* parameter.

References

Fig. 1. γ-ray spectrum in coincidence with incoming andscattered 74 Ni ions. The solid curve is the ﬁt to
the spectrum, which consists of the response function(dashed curve) of γ-ray detectors and a background(dot-dashed curve).
∗1
∗2
∗3
∗4

72

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

1) S. Kanno et al.: RIKEN Accel. Prog. Rep. 38, 66(2005).
2) C. Mazzocchi et al.: Phys. Lett. B 622, 45 (2005).
3) A. F. Lisetskiy et al.: Phys. Rev. C 70, 044314 (2004).
4) O. Sorlin et al.: Phys. Rev. Lett. 88, 092501 (2002).
5) J. Terasaki: Private communication.
6) K. Yamada et al.: Eur. Phys. J. A 25, Suppl. 1, 409(2005).
7) T. W. Burrows: Nucl. Data Sheets 97, 1 (2002).
8) J. K. Tuli: Nucl. Data Sheets 103, 389 (2004).
9) M. Sawicka et al.: Phys. Rev. C 68, 044304 (2003).

RIKEN Accel. Prog. Rep. 39 (2006)

Development of 134 Ce isomeric beam with spin orientation
H. Watanabe,∗1 H. Ueno, A. Yoshimi, D. Kameda, K. Shimada,∗2 D. Nagae,∗2
T. Kishida, Y. Kobayashi, and K. Asahi ∗2[Radioactive beam, isomer]
A nuclear spin ensemble in orientation can be produced by nuclear reaction. In particular, excited states
populated by heavy-ion fusion reactions are highlyoriented due to the large orbital angular momentum
brought in perpendicularly to the direction of projectiles. Aligned isomeric states which have lifetimes
ranging from a few tens of nanoseconds up to submicroseconds become excellent probes of the γ-ray
time diﬀerential perturbed angular distribution (TDPAD) measurement for studies of nuclear moments andhyperﬁne interactions. The objective of this work is to
exploit the spin-aligned isomeric beam of 134 Ce (T1/2 =308 ns, Eex = 3.2 MeV, I π = 10+ , g = −0.183) as aprobe to investigate the magnetic ordering in Ce-based
compounds and alloys from the microscopic viewpoint.
The isomer in 134 Ce has been produced via the9
Be(131 Xe,6n)134 Ce reaction at an energy of 8 AMeV
provided by the RIKEN Ring Cyclotron (RRC). According to a simulation using the LISE code1) with anenergy loss calculation based on the formula of Hubert,2) the recoil energy of the 134 Ce beam emerging
from the 9 Be target (7.5 µm thickness) is 6.1 AMeV
on average. For this recoil energy, the simulation using a charge-state parametrization given by Winger3)
suggests that the Ce ions have a charge distribution
around the most probable value Q = 49+. Even fora single charge state, there are various electronic conﬁgurations, for each of which the hyperﬁne interaction
couples the electronic spin J to the nuclear spin I.
Together they precess around the total atomic spin
F = J + I. In the case of highly ionized atoms traveling in vacuum, the nuclear spin alignment is quickly
attenuated due to the random walk-out in the directionof J .4) Furthermore, when the ions are transported
through the magnetic elements, the electronic spinsprecess very rapidly in the external ﬁelds because of
the large atomic magnetic moments. As a result, theinitial nuclear spin alignment most likely disperses before the isomers arrive at the ﬁnal focal point.
The methodology for preserving the nuclear spinalignment during the separation process is based on thefact that there are no hyperﬁne interactions in atomic
states which have the singlet 1 S0 electronic conﬁguration. In this experiment, the Ce ions at the Q = 48+
charge state, which is equivalent to the Ne-like closed
atomic shell, were transported through the RIPS spec∗1∗2

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

trometer. In such a situation, the precession of nuclear
spin is only caused by the static interaction of the nuclear moment with the external magnetic ﬁelds, which
never wipes out the alignment. Its precession angle
can be calculated to be −23.4◦ for the present spectrometer setup. Because the ions are deﬂected by 90◦
through the RIPS spectrometer, it is expected that theangular distribution of E2 transition is minimum andmaximum at −23.4◦ and 66.6◦ , respectively, with respect to the beam axis. Two Ge detectors were placedat these angles at the ﬁnal focal plane to conﬁrm theanisotropy of γ rays deexciting the isomeric state in134
Ce. The measurements were carried out at three
diﬀerent values of magnetic rigidity which correspondto charge states Q = 46+, 47+, 48+ of the Ce ions.
It is reasonable to assume that the alignment is completely lost during ﬂight in the RIPS spectrometer due
to the hyperﬁne interaction for Q = 46+ and 47+. In
order to eliminate systematic errors, the ratio between
the number of counts measured using the two detectors for each charge state was normalized with that for
Q = 46+ ions. This quantity, called double ratio (DR),is immune to diﬀerences in detection eﬃciency. The
results of the DR for the 948 keV transition in 134 Ce
are shown in Fig. 1. The experimental value of DR =1.076(35) for Q = 48+ indicates a 11% preservation ofalignment.

Fig. 1. Double ratios obtained for 948 keV transition in134
Ce.

References
1) D. Bazin et al.: Nucl. Phys. Phys. A 701, 661 (2002).
2) F. Hubert et al.: Nucl. Data Tables A 7, 233 (1970).
3) J. A. Winger et al.: Nucl. Instrum. Methods Phys. Res.
B 70, 380 (1992).
4) I. Ben Zvi et al.: Nucl. Phys. A 121, 592 (1968).

73

RIKEN Accel. Prog. Rep. 39 (2006)

Study of high-spin states in 49−51 Ti
M. Niikura,∗1 E. Ideguchi,∗1 T. Fukuchi,∗1 H. Baba, 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
In-beam γ-ray spectroscopy with fusion-evaporation
reactions is one of the most eﬃcient methods for the
study of the nuclear structure at high spin since large
angular momentum can be brought into the system.
However, nuclei produced by the fusion reaction using
stable isotope beams are limited, in many cases, to theproton-rich side relative to the line of β-stability. In
order to study high-spin states in the neutron-rich nuclei, 49−51 Ti, we have performed an experiment using
a neutron-rich secondary beam, 46 Ar.
The experiment was performed at the RIPS
facility in RIKEN.1) A 46 Ar beam of 4.0 ±0.3 MeV/nucleon was used to bombarded a 10-µmto induce
the secondary fusion rethick 9 Be target
action, 9 Be 46 Ar, xn 55−x Ti. Gamma rays emitted
from the high-spin states of evaporation residues weredetected by the CNS-GRAPE (Gamma-Ray detector
Array with Position and Energy sensitivity)2) placedaround the secondary target. Details of the experimental setup are described in Ref. 3.
We have obtained the γ-ray spectrum for 49−51 Ti,
and known cascade gamma transitions up to spin
(19/2)− , (11+ ) and (13/2,17/2) states4–6) of 49−51 Ti
were clearly observed, respectively.3)
In order to investigate higher-spin states, we performed a γ-γ coincidence analysis. In Fig. 1 γ-ray
spectra gated by known γ rays of 51 Ti are shown. We
conﬁrmed coincidence relations between known γ rays
and the observed new γ peak at 761 keV. Since this γ
ray is in coincidence with all known cascade γ transitions of 51 Ti, it is placed above the known 3644 keVstate (see right panel of Fig. 1).
In 49 Ti, four γ transitions with the energies of 1543,
963, 785 and 1093 keV were previously reported.4) Figure 2 shows the total projected spectrum gated by
known transitions of 49 Ti. We conﬁrmed the coincidence relations between the four known γ transitions
and, in addition, found a new γ peak at 2370 keV. Since
this peak cannot be seen in the spectrum gated by
the known transitions of 50,51 Ti, this new γ ray was
assigned to a transition from 49 Ti. To interpret the
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8

74

Center for Nuclear Study, University of Tokyo
Department of Physics, Kyushu University
Department of Physics, Royal Institute of Technology, Sweden
Department of Physics, University of Tokyo
Department of Physics, Tohoku University
Institute of Physics, University of Tsukuba
Department of Physics, Kyoto University
TRIUMF, Canada

Fig. 1. γ-ray spectra gated by 890, 907 and 1437 keV of
51
Ti. Gamma rays from 51 Ti and 50 Ti are marked byclosed and open circles, respectively.

Fig. 2. Total projected spectrum gated by known transitions of 49 Ti. Gamma rays from 49 Ti and 50 Ti aremarked by closed and open circles, respectively.

excited levels, we performed shell-model calculations
using the ANTOINE code.7,8) The calculations reprodued the identiﬁed levels well.
Further analysis is still in progress.
References
1) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
461, 309 (1992).
2) S. Shimoura: Nucl. Instrum. Methods Phys. Res. A
525, 188 (2004).
3) E. Ideguchi et al.: AIP Conf. Proc. 764, 136 (2004).
4) M. Behar et al.: Nucl. Phys. A 366, 61 (1981).
5) B. Gass et al.: Phys. Rev. Lett. 40, 1313 (1978).
6) S. E. Arnell et al.: Phys. Scr. 6, 222 (1972).
7) E. Caurier: Shell-model code ANTOINE (Institut deRecherches Subatomiques, Strasbourg, 1989–2002).
8) E. Caurier and F. Nowacki: Acta Phys. Pol. B 30, 705(1999).

RIKEN Accel. Prog. Rep. 39 (2006)

Search for high-spin isomers in N = 51 isotones using CRIB
Y. Wakabayashi,∗1,∗2 A. Odahara,∗3 Y. Gono, T. Fukuchi,∗4 T. Teranishi,∗1 S. Kubono,∗2 H. Yamaguchi,∗2
A. Saito,∗2 E. Ideguchi,∗2 S. Nishimura, J. J. He,∗2 H. Fujikawa,∗2 A. Guilherme,∗2 S. Ota,∗5 J. Y. Moon,∗6
M. Notani,∗7 Y. Yanagisawa, S. Michimasa, S. Shimoura,∗2 H. Watanabe,∗8 T. Kishida, H. Baba, and T. Ishii∗9[High-spin isomer, γγ coincidence, unstable nuclear beams]
High-spin isomers are known in N = 83 isotones systematically.1) These isomers are of stretch-coupled conﬁgurations of valence nucleons excited by the breakingof neutron magic 82 and proton semimagic 64 cores.
They are considered to be shape isomers because theisomerism is attributed to sudden shape changes fromnear-spherical to oblate shapes. To search for thesame type of isomer in other mass regions, we selected N = 51 isotones, which have one neutron outside the magic 50 core and proton numbers close to thesemimagic 40 core.
We developed a 17 N secondary beam using the lowenergy radioisotope beam separator (CRIB)2,3) of theCenter for Nuclear Study (CNS), University of Tokyo,
to search for high-spin isomers in N = 51 isotones.
Because the nuclei with Z < 40 of N = 51 isotones
are close to the line of stability, it is diﬃcult to produce high-spin states in these nuclei using reactions
by combinations of stable beams and targets. Therefore, it is very eﬀective to use radioisotope beams. By
γ-ray spectroscopy, high-spin isomers can be searched
for in the nuclei 90 Y, 89 Sr and 88 Rb produced by the
α5n, αp5n, 2α3n evaporation channels in the fusion
reaction of 82 Se+17 N, respectively.
An experiment that involved searching for isomers
was carried out in Dec. 2004. A self-supporting 9 Be
target of 2.3 mg/cm2 thickness was bombarded by an
18 8+Oprimary beam at 126 MeV to obtain a 17 N
beam. The beam current was 0.55 particle µA at
the primary target position. A parallel-plate avalanche
counter (PPAC) was set at a dispersive focal plane (F1)for beam monitoring. To identify reaction products, a
PPAC and a Si detector of 1.5 mm thickness were installed at an achromatic focal plane (F2) before the
Wien Filter. A 82 Se secondary target of 4.9 mg/cm2
thickness was placed at a ﬁnal focal plane (F3). A
PPAC and a 72-µm-thick Si detector were also placed
just upstream and downstream of the secondary target,
respectively, to distinguish the secondary fusion reaction products from the secondary beam. Two clover
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8
∗9

Department of Physics, Kyushu University
Center for Nuclear Study, University of Tokyo
Department of Physics, Osaka University
Department of Physics, Rikkyo University
Department of Physics, Kyoto University
Chung-Ang University, Korea
Physics Division, Argonne National Laboratory, USA
Department of Nuclear Physics, The Australian National
University, Australia
Japan Atomic Energy Agency

Ge detectors were set to measure the γ rays emitted
from the nuclei produced by the secondary fusion reaction. These Ge detectors were surrounded by paraﬃn,
cadmium and lead to reduce background γ rays fromthermal neutron capture reaction products. The intensity and purity of the 17 N7+ secondary beam were
2.3 × 104 particles/s and 21%, respectively, at the secondary target position.
In this experiment, some γ rays from nuclei, suchas 93 Nb, produced by the 82 Se+17 N reaction were observed, as shown in Fig. 1, which shows energy spectra obtained using Ge detectors. Spectrum (a) shows
the total projection spectrum of the γγ prompt coincidence measurement. The gate width of prompt γγ
timing was set to 200 nsec. Spectrum (b) shows a delayed γγ projection spectrum whose delayed time wasset in the range of 1 to 2 µsec from prompt timing,
where prompt and delayed indicate the condition of
the time diﬀerence between two γ rays in coincidence.
In spectrum (a) in Fig. 1, a possible indication of
the existence of the 1535 keV peak, which is the lowest transition feeding a long-lived isomer 7+ (T1/2 =3.19 h), was obtained. This nucleus is one of the relevant nuclei in N = 51 isotones. A clearer indication
can also be seen in (b) of Fig. 1. If these indications
are proven in further data analyses, such as the optimization of various gate conditions, it means that there
exists a relatively long lived isomer in 90 Y.

Fig. 1. Projection spectra of γγ coincidence under two time
conditions. The time conditions of spectra (a) and (b)are given in 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).
3) Y. Yanagisawa et al.: Nucl. Instrum. Methods Phys.
Res. A 539, 73 (2005).

75

RIKEN Accel. Prog. Rep. 39 (2006)

Observation of second decay chain from 278 113
K. Morita, K. Morimoto, D. Kaji, T. Akiyama,∗1 T. Suda, H. Haba, A. Yoshida, E. Ideguchi,∗2 S. Goto,
F. Tokanai, H. Koura, A. Ozawa, T. Ohnishi, T. Yamaguchi, H. Kudo, K. Sueki, A. Yoneda, and N. Sato∗3
278

113, production and decay, gas-ﬁlled recoil ion separator
We observed one decay chain, which was the convincing candidate event originating from an isotope of
the 113th element, 278 113 in the 209 Bi + 70 Zn reaction in 20041) at RIKEN Linear Accelerator (RILAC)
facility. In continuing the experiment to search formore events in the same reaction for conﬁrming theﬁrst event, we observed one more decay chain thisyear. The production cross sections of isotopes of thehighest-atomic-number region in the fusion reaction
become extremely small with the increase in atomic
number. For example, according to our previous measurements in 2003 and 2004 to produce the isotope
278
113 mentioned above, the cross section was deduced−39cm2 ). We carried out the
to be 55 +130
−45 fb (fb = 10
reproduction experiment from January 20 to October
20, this year with several intermissions. The net irradiation time was 87.2 days. The second decay chain
was observed at 2:18 (JST) on April 2.
All the experimental conditions were almost identical to those used in previous runs.1) A 70 Zn ion beamof 353 MeV was extracted from RILAC. The absoluteaccuracy of the beam energy was ±0.6 MeV. Targets
were prepared by the vacuum evaporation of metallic
bismuth, onto carbon backing foils of 30 µg/cm2 thickness. The thickness of the bismuth layer was about
450 µg/cm2 . The beam energy at the half-depth oftargets was estimated to be 349.5 MeV. The reaction
products were separated in-ﬂight from the beam bya gas-ﬁlled recoil ion separator, GARIS,1) and wereguided into a detector box placed at the focal plane of
GARIS. The separator was ﬁlled with helium gas at apressure of 86 Pa. The magnetic rigidity of GARIS
for evaporation residue measurement was set to be
2.09 Tm. The total dose of 70 Zn from Jan. to Oct.
2005 was 2.46 × 1019 .
The second chain was observed during irradiation.
This decay chain consisted of four consecutive alphadecays followed by a spontaneous ﬁssion after the implantation of an evaporation residue in the focal plane
detector of GARIS. Energies, time diﬀerences between
events, positions in the detector of the event are listed
in the second column of Table 1 together with thoseobserved in previous runs (ﬁrst column). In the table,
ER denotes the evaporation residue, and SF denotes
the spontaneous ﬁssion. In the third alpha decay of thesecond chain, decay energy was measured only partly
∗1
∗2
∗3

76

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

Table 1. Summary of observed events. Number in parentheses denotes an energy resolution in FWHM. ∆T :Time diﬀerences between events. Position: measured
from the bottom of the detector.
chain 1E (MeV)∆T
Position
36.75
30.3 mmchain 2E (MeV)∆T
Position
36.47
30.1 mmα111.68 (0.04)
0.344 ms
30.5 mm

11.52 (0.04)
4.93 ms
30.2 mmα211.15 (0.07)
9.26 ms
30.4 mm11.31 (0.07)
34.3 ms
29.6 mmα310.03 (0.07)
7.16 ms
29.8 mm2.32 (escape)1.63 s29.5 mmα49.08 (0.04)
2.47 s30.9 mm

9.77 (0.04)
1.31 s29.7 mmSF

204.1
40.9 s30.3 mm

192.3
0.787 s30.5 mmER

Nuclide

278

113

274

270

266

262

Rg

Mt

Bh

Db

because of the limited solid angle coverage (85%) of
the detector box.
The observed decay is the same as that observed in
the ﬁrst decay chain. Decay times observed in bothchains are consistent, indicating that they have thesame origins. Decay energies in both chains show somediscrepancies. However, considering that the observation in the rather widely distributed decay energies ofthe decay chains of odd-odd nucleus 272 Rg,2) these two
decay chains are consistently assigned to those originating from 278 113. The production cross section is
deduced from the present event to be 38+88−32 fb, which
agrees well with that obtained in previous runs. Thenaverage production the cross section is deduced to be
45+59−29 fb by combining the two values.
References
1) K. Morita, K. Morimoto, D. Kaji, T. Akiyama et al.: J.
Phys. Soc. Jpn. 73, 2593 (2004).
2) K. Morita, K. Morimoto, D. Kaji et al.: J. Phys. Soc.
Jpn. 73, 1738 (2004).

RIKEN Accel. Prog. Rep. 39 (2006)

Electron scattering from unstable nuclei
by novel SCRIT method (III)T. Suda, T. Emoto, Y. Furukawa,∗2 S. Ito, T. Koseki, K. Kurita,∗1 T. Masuda,∗1
M. Nakamura, T. Tamae,∗2 M. Wakasugi, S. Wang, and Y. Yano[SCRIT, electron scattering, luminosity determination]
We have been intensively carrying out feasibility
studies for a novel SCRIT (Self-Conﬁning RI Target)
scheme1) at an existing electron storage ring, KSR of
Kyoto University, for future electron-RI scattering experiments.
As already reported,2–4) the trapping of externallyinjected ions by circulating electron beams was clearly
conﬁrmed by detecting ions after some trapping period, on an order of a second, by extracting from thetrapping potential.
This is not, however, direct evidence that all ionsexist on the electron beam, since the ions can also spiral around the electron beam. The main eﬀort madethis year was, thus, to observe direct evidence of thespatial overlap of the ions with the electron beam; inanother words, luminosity determination.
As a luminosity monitor, a high-energy γ-ray detector, BaF2 , was prepared for detecting bremsstrahlung
from the trapped ions. During the series of test experiments, a huge background was revealed for thebremsstrahlung luminosity monitor. A typical counting rate of the BaF2 detector was a few kHz, whereas
the expected rate for a luminosity of 1025 /cm2 /s is
20 Hz. We found that the sources of the backgroundare due to, 1) bremsstrahlung from residual gas ionstrapped by the electron beam, and 2) electromagnetic
showers produced at the beam pipe where the βy ofthe ring parameters becomes maximum.
The number of trapped gas ions calculated from the
BaF2 counting rate is found to be consistent with thenumber of gas ions, which explains the beam life timeof KSR. What we did in this year for this purpose arelisted below.
• Ion clearer installation:
An ion clearer is a pair of electrodes, which sandwiches the electron beam. By applying high voltage to the electrodes, one can eﬀectively remove
the trapped gas ions from the electron beam. A
numerical simulation predicted a nearly one-order
reduction of the number of trapped gas ions.
• New beam pipe installation:
The background reduction due to the electromagnetic shower is realized by enlarging the aperture;
inner diameter of the beam pipe. We designed
new beam pipes at the quadruple magnets, where∗1∗2

βy is maximum (Fig. 1), to keep suﬃciently large
aperture for the storage electron beam.
• Collimator installation:
In addition, a Geant simulation suggests that acollimator placed close to the circulating electron beam to remove the beam halo is eﬀective
in reducing the background from upstream. A
thick collimator, having dimensions of ±20 mm forvertical and ±50 mm for horizontal, for a highvacuum environment was installed inside the vacuum chamber.
After successful installation of the ion clearers, beam
pipes and collimator, the whole electron ring, including
the SCRIT prototype, was backed for about one week.
Vacuum of tpically 10−8 Pa was achieved. Self-cleaning
operation of KSR subsequently followed the backing tofurther improve the vacuum, which was completed by
the end of November.
We are now ready to restart feasibility studies of the
SCRIT scheme at KSR for determining the luminosity
by observing the bremsstrahlung from trapped ions in
SCRIT.

Fig. 1. Straight section of KSR, where the SCRIT prototype is installed. The bremsstrahlung luminosity monitor is positioned in the downstream of the straight section. The newly installed beam pipes at position where
βy becomes maximum are indicated.

References
1) M. Wakasugi, T. Suda, and Y. Yano: Nucl. Instrum.
Methods Phys. Res. A 532, 216 (2004).
2) T. Suda and M. Wakasugi: Prog. Part. Nucl. Phys. 55,
417 (2005).
3) T. Suda et al.: RIKEN Accel. Prog. Rep. 38, 71 (2005).
4) M. Wakasugi et al.: J. Part. Accel. Soc. Jpn. 2, 59(2005).

Rikkyo Univesity
Tohoku Univesity

77

RIKEN Accel. Prog. Rep. 39 (2006)

Observation of medium modifications for ρ and ω mesons†
M. Naruki, H. En’yo, R. Muto, F. Sakuma,∗ T. Tabaru, and S. Yokkaichi,∗for the KEK-PS E325 Collaboration[Vector meson, mass modiﬁcation, chiral symmetry, QCD]
The experiment E325 has been performed at the
KEK 12-GeV Proton Synchrotron to measure the invariant mass spectra of ρ, ω, φ → e+ e− and φ →K + K − decay modes simultaneously. This was the ﬁrst
dilepton measurement of the modiﬁcation of the vector
meson mass in a nucleus.
Figure 1 shows the invariant mass spectra of thee+ e− pairs using all of the data taken in 2002. The invariant mass spectra were ﬁtted with a combinatorial
background and known hadronic sources: ρ → e+ e− ,
ω → e+ e− , φ → e+ e− , η → e+ e− γ, and ω → e+ e− π 0 .
The background was evaluated by the event-mixing
method. The mass resolution and the detector eﬀect ofour spectrometer were taken into account through thedetector simulation using Geant4. The relative abundances of these components were determined by the ﬁtting, except for the ratio of ω → e+ e− π 0 to ω → e+ e−
decay, which was ﬁxed to in-vacuum branching ratios,59/6.95 given by the PDG. The ﬁt results are plottedwith the solid lines in Fig. 1. The region from 0.6 to
0.76 GeV/c2 was excluded from the ﬁt.
A signiﬁcant excess can be seen on the low-mass sideof the ω peak, whereas the high-mass tail of ω can be
reproduced with the expected shapes. After the acceptance correction, the 95% C.L. allowed parameterregions are obtained as ρ/ω < 0.15 and ρ/ω < 0.31
for C and Cu targets, respectively. These values aremuch smaller than one, as was previously measured in
pp interactions at the same energy.1) A possible explanation of the small ρ/ω is that the most of the ρ decay
inside the nuclei due to their short lifetime, thereforethe ρ with the vacuum shape is highly suppressed, andthe modiﬁed ρ contributes to the excess.
A comparison has been made between the data anda model considering in-medium mass modiﬁcation. In
this model, mass decreases linearly as a function of thedensity ρ; m(ρ)/m(0)  1−k(ρ/ρ0 ).2) A Woods-Saxon
shape was used for the nuclear density distribution.
We assumed that the vector mesons were generated
at the surface of an incident hemisphere of the target
nucleus. We ﬁt the entire mass region of Fig. 1 withthe modiﬁed shapes of ρ and ω. The ﬁt results, after subtracting the combinatorial background and theshapes of η → e+ e− γ and ω → e+ e− π 0 are shown in
Fig. 2. The spectra for both C and Cu targets can be
reproduced quite well using this model. We obtained
the shift parameter of k = 0.092 ± 0.002. The best-ﬁt†∗

78

Condensed from the article in nucl-ex/0504016
Department of Physics, Kyoto University

Fig. 1. Invariant mass spectra of e+ e− for (a) C and (b) Cu
targets. The solid lines are the best-fit results, which
are the sums of the known hadronic decays. ρ → e+ e−
is not visible (see text).

Fig. 2. Result of model calculation considering in-media
modification for (a) C and (b) Cu targets. The background and the shapes of η → e+ e− γ and ω → e+ e− π 0were subtracted. The shapes of ω → e+ e− (dotted) andρ → e+ e− (dash-dotted) were modified according to themodel using the formula m(ρ)/m(0) = 1 − k(ρ/ρ0 ) withk = 0.092.

ρ/ω ratios are 0.7 ± 0.1 and 0.9 ± 0.2 for the C andCu targets, respectively. It is concluded that the observed modiﬁcation can be understood with the modelin which the masses of the ρ and ω mesons decrease by
9% at normal nuclear density. This value is consistent
with the theoretical prediction.2)
This work was partly funded by the RIKEN Special
Postdoctoral Researchers Program. We thank the staﬀ
members of RIKEN Super Combined Cluster system
and RIKEN-CCJ.
References
1) V. Blobel et al.: Phys. Lett. B 48, 73 (1974).
2) T. Hatsuda and S. H. Lee: Phys. Rev. C 46, R34 (1992).

RIKEN Accel. Prog. Rep. 39 (2006)

Nuclear mass number dependence of inclusive omega and phi meson
productions in 12 GeV p-A collisions
T. Tabaru, H. En’yo, R. Muto, M. Naruki, F. Sakuma,∗ and S. Yokkaichi, for the KEK-PS E325 Collaboration[Mass number dependence, vector meson]
The mass modiﬁcation of mesons in nuclear matter has been studied recently. We, KEK-PS E325
experiment group, have reported that such modiﬁcation has be seen in ρ0 /ω and φ meson productions in
12 GeV p+A collisions.1–3) To understand such a phenomenon, basic measurements of meson production,such as the nuclear mass number dependence of production cross section, are important. In this article,
we discuss the nuclear mass number dependence using the same data with which we observed the mass
modiﬁcation of mesons.
Introducing the parameter α representing the nuclear mass number dependence, the production crosssection σ(A) can be parameterized as σ(A) = σ0 Aα ,for collisions of protons and nuclei with the mass number A. In the hadronic production of light mesons such
as π and ρ mesons, the α parameter is about 2/3.4,5)
On the other hand, the α parameter is close to unity inhard reactions like J/ψ production.5–7) The α parameter of φ mesons is measured as 0.81 to 0.96 at a collision√energy sN N of approximately 10 GeV.8–10) In our experiment, ω and φ mesons were measured in medium√
energy collisions of 12 GeV p+A ( sN N = 5.1 GeV).
At this collision energy, there has been no measurements of the α parameters of ω and φ mesons so far.
Our experiment was performed using the EP1B beam line of the 12 GeV proton synchrotron in
the High Energy Accelerator Research Organization(KEK). The proton beam was delivered onto carbon(C) and copper (Cu) targets, and the produced e+ e−pairs were measured by our spectrometer covering the
backward regions; the rapidity (y) range from 0.3 to 1.7
and transverse momentum (pT ) range below 1 GeV/c.
The momenta of charged tracks were measured using cylindrical drift chambers in a magnetic ﬁeld of
0.81 T·m. The electron ID was realized by the cascade operation of gas Čerenkov counters using isobutane and electromagnetic lead-glass calorimeters. The
spectrometer acceptance was estimated by a GEANT4
simulation.
The measured invariant mass spectra were decomposed into correlated pairs from meson decays anduncorrelated pairs of combinatorial background. By
breaking down the present spectra into these expectedcomponents, we obtained the yield of mesons in theregion of 0.9 < y < 1.7 and pT < 0.75 GeV/c. Finally,∗

the α parameter is obtained as shown in Fig. 1. The
errors are statistical errors.
Although the mass diﬀerence between ω and φmesons is small, we obtained it as the experimental
result that the α parameter of φ meson production
is larger than that of ω meson production. Similarly,
the nuclear cascade simulation JAM11) gives a larger
α parameter for φ meson production than for ω meson
production, as shown in Fig. 1. In the JAM calculation, the ω meson is produced from both primary andsecondary reactions, while the φ meson is produced
mainly from secondary reactions. This suggests thatthe diﬀerence in α parameters between φ and ω mesons
is explained by the diﬀerence in the primary and secondary production ratio.
In the analysis, we have used CC-J and RSCC at
RIKEN. We would like to thank the staﬀ members of
CC-J and RSCC for their support.

Fig. 1. α parameters of φ and ω mesons in present data(squares and circles) and JAM results (dotted anddashed lines).

References
1) K. Ozawa et al.: Phys. Rev. Lett. 86, 5019 (2001).
2) M. Naruki et al.: nucl-ex/0504016.
3) R. Muto et al.: nucl-ex/0511019.
4) M. Ono et al.: Phys. Lett. B 84, 515 (1979).
5) M. Binkley et al.: Phys. Rev. Lett. 37, 571 (1976).
6) B. Alessandro et al.: Eur. Phys. J. C 33, 31 (2004).
7) U. Husemann: Nucl. Phys. B 142, 104 (2005).
8) C. Daum et al.: Z. Phys. C 18, 1 (1983).
9) R. Bailey et al.: Z. Phys. C 24, 111 (1984).
10) A. N. Aleev et al.: Czech. J. Phys. 42, 11 (1992).
11) Y. Nara et al.: Phys. Rev. C 61, 024901 (1999).

Department of Physics, Kyoto University

79

RIKEN Accel. Prog. Rep. 39 (2006)

Evidence for φ meson modification in nuclear medium†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]
The KEK-PS E325 experiment was conducted at
KEK Proton Synchrotron to detect possible in-medium
modiﬁcation of vector mesons. The invariant mass
spectra of φ → e+ e− decays were measured in 12-GeV
p + A interactions. Data was obtained from 1997 to
2002. Copper and carbon targets were used to study
the nuclear size dependence of e+ e− invariant mass
distributions.
We divided the data into three parts based on theβγ values of the observed e+ e− pairs, βγ < 1.25,
1.25 < βγ < 1.75, and 1.75 < βγ. We ﬁtted eachmass spectrum with a resonance shape of φ → e+ e−
and a quadratic background curve (see Fig. 1). A signiﬁcant excess over the expected mass spectrum on the
low-mass side of the φ meson peak was observed in thelowest βγ region of φ mesons (βγ < 1.25) with copper targets. However, in the middle- and high-βγ regions (βγ > 1.25), the spectral shapes of φ mesons arewell described by the Breit-Wigner shape when experimental eﬀects such as multiple scattering and energy
loss of particles, tracking performance with chamber
resolution, and misalignment of tracking devices, areconsidered. This excess is considered to be the signalof the mass modiﬁcation of the φ mesons in a target
nucleus because the eﬀect is visible only for slow φmesons produced in a large target nucleus.
To evaluate the amount of excess Nex , we repeatedthe same ﬁt procedure to the spectrum except forthe mass region where the excess was observed (from0.95 GeV/c2 to 1.01 GeV/c2 ). We obtained Nex as ayield of excess from the ﬁt result. The ratio of excess tototal φ yield, Nex /(Nex +Nφ ), is plotted in Fig. 2. The
excess is statistically signiﬁcant for the copper target
data in the lowest-βγ bin, whereas it is marginal forthe carbon target data.
We attempted to reproduce the βγ dependence ofthe excess with a Monte-Carlo-type model calculationthat includes the in-medium mass modiﬁcation of the
φ mesons based on the theoretical prediction.1,2) We
assumed the density dependence of the φ meson mass
as mφ (ρ)/mφ (0) = 1 − k(ρ/ρ0 ), where ρ0 is normal
nuclear density.1) To reproduce the large amount ofexcess in our data (29% for the lowest-βγ bin for Cu),
it is necessary to introduce a broadening of the total
width of φ (Γφ ), or at least of the partial width for
φ → e+ e− decay (Γφ→ee ). For the total width broadening, we adopted Γφ (ρ0 ) ∼ 47 MeV/c2 in accordancewith Ref. 2. The density dependence of width Γφ (ρ)†∗

80Condensed from the article in nucl-ex/0511019
Department of Physics, Kyoto University

Fig. 1. Obtained e+ e− distributions with fit results. Target and βγ -region are shown in each panel. The points
with error bars represent the data. The solid lines represent the fit results. The dotted lines represent thebackground curve.

Fig. 2. βγ dependence of Nex /(Nφ + Nex ) for both data
and model calculation. The points represent the data
and the lines represent the model calculation results.

was assumed to be Γφ (ρ)/Γφ (ρ0 ) − 1 ∝ ρ/ρ0 and thebranching ratio Γφ→ee /Γφ remained unchanged in themedium. Figure 2 shows the Nex /(Nφ + Nex ) from thedata and the model calculation with shift parameters
k of 0.02 and 0.04. The tendency of the data is well
reproduced by the model calculation with the shift parameter of k = 0.04.
In these analyses, we used the excellent cpu powerof CC-J and RSCC at RIKEN.3) We are grateful forthe support from these computing facilities.
References
1) T. Hatsuda and S. H. Lee: Phys. Rev. C 45, R34 (1992).
2) F. Klingl, T. Waas, and W. Weise: Phys. Lett. B 431,
254 (1998).
3) S. Kametani et al.: RIKEN Accel. Prog. Rep. 39, 224(2006).

RIKEN Accel. Prog. Rep. 39 (2006)

Nuclear size dependence of φ meson production via e+ e− and K + K −decay channel in 12 GeV p+A reaction at KEK-PS
F. Sakuma,∗ H. En’yo, M. Naruki, R. Muto, T. Tabaru, and S. Yokkaichi for KEK-PS E325 Collaboration[Vector meson, in-medium modiﬁcation, e+ e− , K + K − ]In the experiment KEK-PS E325, we have measurede e and K + K − pairs produced in 12 GeV p+A reaction, in order to study the chiral property of dense
nuclear matter through the analysis of invariant mass
spectra. We have already reported the modiﬁcationof ρ/ω meson spectra at normal nuclear matter density.1,2) Moreover, we have recently observed the modiﬁcation of the φ meson spectrum via the e+ e− decay
channel.3) The simple toy model calculation in Ref. 3,
it is assumed that the total and partial width change
and the mass shift at normal nuclear matter density,
reproduces the tendency of our data. The modiﬁcation of the width of a φ meson is predicted as a consequence of modiﬁcations of kaon-nucleon interactions ina nuclear matter.4) Therefore, the medium eﬀect could
be observed as a diﬀerence in partial width between
φ → e+ e− (Γφ→e+ e− ) and φ → K + K − (Γφ→K + K − ).
That is we could observe the diﬀerence in the nuclear
size dependence of production cross section between
the e+ e− and the K + K − decay channel, because alarger modiﬁcation is expected in a larger nucleus. We
parametrize the nuclear size dependence of production
cross section σ(A) with α,+ −tor response in Geant4 simulation6) according to thekinematical distribution of φ mesons. The kinematical
distribution of φ mesons was obtained by the nuclear
cascade code JAM.7) And for the background shape,
we used the quadratic curve for e+ e− and the event
mixing method for K + K − .
The preliminary results for the α parameter obtained as functions of βγ are plotted in Fig. 1. In
this ﬁgure, αφ→K + K − seems larger than αφ→e+ e−
in the lower βγ region.
This suggests that
Γφ→K + K − /Γφ→e+ e− is increased by the modiﬁcationof the φ meson and kaon at normal nuclear matter
density, as discussed above.
To expedite the analysis, we have used CC-J and
RSCC at RIKEN. We would like to thank the staﬀ
members of CC-J and RSCC for support.

σ (A) = σ (A = 1) × Aα ,for the collisions between a proton and the nucleus
with the mass number A. The diﬀerence in nuclear
size dependence α is expected to be enhanced in slowly
moving φ mesons that have a large probability of decay inside the nucleus. For example, if the φ meson
is modiﬁed and Γφ→K + K − /Γφ→e+ e− increases in a nucleus, Nφ→K + K − /Nφ→e+ e− that we can observe becomes large, where Nφ is the number of φ mesons.
Then, αφ→K + K − should be larger than αφ→e+ e− inslowly moving φ mesons.
In the present article, we report the results of analysis of all the data taken in 2001/2002. In order toobserve the nuclear size dependence, we accumulated
data using two types of target, carbon and copper. A
detailed description of the E325 spectrometer can befound elsewhere.5) The detector acceptance is diﬀerent
between e+ e− and K + K − , but there is an overlapping
region.
To evaluate the yield of φ mesons, we ﬁt mass spectra with the φ meson shape and the background shape.
For the φ meson shape, we used the Breit-Wigner
curve with a natural mass (1019.456 MeV/c2 ) and decay width (4.26 MeV/c2 ) convoluted over the detec∗

Fig. 1. Preliminary results for α parameter of φ →e+ e− (closed circle) and φ → K + K − (open circle) shown
as functions of βγ.

References
1) K. Ozawa et al.: Phys. Rev. Lett. 86, 5019 (2001).
2) M. Naruki et al.: nucl-ex/0504016
3) R. Muto et al.: nucl-ex/0511019
4) F. Klingl, T. Waas, and W. Weise: Phys. Lett. B 431,
254 (1998).
5) M. Sekimoto et al.: Nucl. Instrum. Methods Phys. Res.
A 516, 390 (2004).
6) http://geant4.web.cern.ch/geant4/
7) Y. Nara et al.: Phys. Rev. C 61, 024901 (1999).

Department of Physics, Kyoto University

81

RIKEN Accel. Prog. Rep. 39 (2006)

Muon catalyzed fusion in non-equilibrium D2 +T2 mixtures
K. Ishida, T. Matsuzaki, Y. Matsuda, M. Iwasaki, K. Nagamine,∗1 N. Kawamura,∗2 H. Imao,∗3
S. N. Nakamura,∗4 M. Kato,∗5 H. Sugai,∗5 A. Uritani,∗6 H. Harano,∗6 T. Matsumoto,∗6 and G. H. Eaton∗7[Muon, fusion, deuterium, tritium]
In muon catalyzed fusion (µCF) cycle, muonic
molecule formation has to occur rapidly for a muon
to catalyze many fusions during its lifetime (2.2 µs). It
is considered that dtµ formation proceeds as follows,(tµ)F + (DX)Ki νi → [(dtµ)xee]Kf νf (x = d, t, X =D, T), where F is the hyperﬁne state and Ki νi andKf νf are the rotational and vibrational states, respectively. Here, the sum of the initial kinetic energy
and the energy released by dtµ formation is resonantly
absorbed by the excitation (Kf νf ) of the ﬁnal compound molecule, therefore, the formation rate is signiﬁcantly enhanced compared with the rate by nonresonant (Auger) formation only. Theoretical calculations such as the temperature dependence of the formation rate are generally consistent with results forgas phase, but predict too small rates for liquids andsolids. Thus, further investigation is necessary for acomplete understanding of this phenomena.
In a previous measurement done at RIKEN-RAL
Muon Facility, we have shown that dtµ formation ratewith D2 is signiﬁcantly higher than that with DT.1)
Because the resonance condition is also dependent on
the rotational levels of the D2 molecule, an experiment
which varies the ortho- (rotational states Ki = 0, 2, . . .)to para-D2 (Ki = 1, 3, . . .) composition ratio of thetarget will provide valuable additional inputs to thedevelopment of the theory.
Such a measurement was successfuly done ﬁrst forddµ formation in pure D2 by our group.2) We haveobserved that the ddµ formation rates in ortho-richliquid and solid D2 decrease by about 30 % comparedwith those in normal D2 . It is predicted that the eﬀect
will be much more enhanced for dtµ formation because
the dtµ molecule has a much shallower bound state andthe resonance condition can be more sensitive to theinitial molecular states. Several calculations suggestthat dtµ formation rate with para-D2 is much higher
than that with ortho-D2 .
To test this prediction, we have recently carriedout µCF measurements comparing ortho-rich D2 andnormal-D2 . Ortho-D2 was selected primarily because
it is more easily produced than para-D2 . Figure 1
∗1
∗2
∗3
∗4
∗5
∗6
∗7

82

Physics Department, University of California, USA
Muon Science Laboratory, High Energy Accelerator Research Organization (KEK)
Department of Physics, University of Tokyo
Department of Physics, Tohoku University
Department of Radioisotopes, Japan Atomic Energy Agency
Quantum Radiation Division, National Institute of Advanced Industrial Science and Technology
ISIS, Rutherford Appleton Laboratory, UK

Fig. 1. µCF cycling rate as function of time after D2 andT2 mixing. Cases using normal-D2 and ortho-D2 arecompared.

shows the measured µCF cycling rate in each hour after
D2 (50%) and T2 (50%) mixing. When we mix D2 andT2 , an equilibrium state is gradually reached due to
2DT. Data were taken for thethe reaction D2 + T2
liquid state up to 96 h in the previous run with normalD2 (ﬁlled circles in Fig. 1) and up to 75 h in the new
run with ortho-D2 (open circles). In both cases, thetarget D/T gas was then warmed up to room temperature to accelerate the equilibration and was liqueﬁed
again to obtain data with a fully equilibrated target(ﬁlled and open squares).
It can be observed that the cycling rate was enhanced by 30% in the non-equilibrium state just after
D2 +T2 mixing. The result is well explained by taking
account of the higher resonant formation rate with D2
and the equilibration process with a time constant of
56 h.
Concerning the ortho-para eﬀect, the diﬀerence between the two conditions was not as large as expected.
Two distinguished data points at the beginning of theortho-D2 data were actually the result of an accidentally introduced impurity.
We are not yet sure why the diﬀerence between
normal-D2 and ortho-D2 was very small. It could bethat the conversion of ortho-D2 to normal-D2 has occurred in less than two hours due to the presence ofradioactive tritium. Another possibility is that thediﬀerence in dtµ formation rate is unexpectedly small.
We plan to develop a method for in-situ gas analysis
to distinguish between these possibilities.
References
1) K. Ishida et al.: RIKEN Accel. Prog. Rep. 35, 39(2002).
2) H. Imao et al.: Phys. Lett. B 632, 192 (2006).

RIKEN Accel. Prog. Rep. 39 (2006)

Measurement of Doppler broadening width of Kα X-rays from µ− αatoms formed in muon sticking process of muon catalyzed t-t fusion
T. Matsuzaki, K. Ishida, N. Kawamura,∗1 H. Imao,∗1,∗2 Y. Matsuda, M. Iwasaki, S. N. Nakamura,∗3 M. Kato,∗4
H. Sugai,∗4 G. H. Eaton,∗5 and K. Nagamine∗6Muon catalyzed t-t fusion, muonic Kα X-rays, Doppler broadening width, particle
correlations
The muon catalyzed t-t fusion (t-t µCF) process proceeds spontaneously by stopping negative muons in atritium (T2 ) target. tµ− atoms are formed by muons
being bound to triton nuclei (t), and then collide with
T2 molecules without receiving any Coulomb repulsive force to form ttµ− molecules. The t+t fusion
reactions occur in the framework of ttµ− molecules,
and induce three-particle decays of an α-particle andtwo neutrons. After the fusion reaction, the muon isliberated and participates again in the next t-t µCF
process. The t-t µCF process is described in Eq. (1),where the muon is 9-fold lighter than a proton or 207fold heavier than an electron.
t + t + µ− → ttµ−
→ α + n + n + µ− + Q(11.33 MeV) (1)→ µα + n + n + Q(2)This t+t reaction is very unique from the viewpoint of
nuclear reaction mechanism, because the t+t system isformed in the ttµ− molecule with a molecular binding
energy, and decays to three particles. Therefore, thet+t reaction mechanism can be studied by observing
the behavior of outgoing particles: two fusion neutrons
and an α-particle.
With some probability, the liberated muon is captured by the α-particle to terminate the t-t µCF cycle
described in Eq. (2); this phenomenon called muon
sticking. In this process, the µ− α atom recoils in thetarget medium at a given kinetic energy by the reaction
mechanism at the exit channel. In addition, characteristic muonic X-rays are emitted from the recoiling µ− αatoms; thereby, the observed X-ray lines show Doppler
broadening which reﬂects the velocity distribution ofµ− α atoms eﬀective for the observation direction. By
measuring the Doppler broadening width, we can determine the mean value in the velocity distribution ofµ− α atoms, and obtain information on the mean kinetic energy of µ− α atoms, which is deeply dependent
on the mechanism of three-particle decay at the exit
channel.
∗1
∗2
∗3
∗4
∗5
∗6

Meson Science Laboratory, High Energy Accelerator Research Organization
Faculty of Science, University of Tokyo
Department of Physics, Tohoku University
Japan Atomic Energy Research Institute
ISIS, Rutherford Appleton Laboratory, UK
Physics Department, University of California, USA

We conducted X-ray measurements associated withthe t-t µCF process using high-purity solid and liquid T2 targets at the RIKEN-RAL Muon Facility.1,2)
We observed Kα X-rays originating from muonic helium atoms (µ− α) formed by the muon sticking process,3,4) and determined Doppler broadening widths(∆Eγ = 0.147 +/− 0.014 keV for the solid target and
0.138 +/− 0.029 keV for the liquid target). Then, we
obtained the mean total kinetic energies of µα− atoms,(Ekin = 1.9 +/− 0.4 MeV for the solid target and1.7 +/− 0.7 MeV for the liquid target) and comparedthese energies with the calculated kinetic energies of
α-particles assuming three limiting cases, namely, no
particle correlations, n-n correlations and n-α correlations at the exit channel of t+t reactions. It wasconsequently shown that the obtained Ekin values were
well in agreement with the kinetic energies calculated
by reaction kinetics assuming either strong n-α particle correlations (sequential neutron decay through 5 He
resonance states) or no particle correlations. The former case gave a continuous energy distribution fromzero to a maximum of 3.8 MeV with a mean energyof 1.9 MeV, and the latter case gave the kinetic energies of 1.6–1.9 MeV through the p3/2 resonance and
0.1–2.1 MeV through the p1/2 resonance. On the other
hand, the obtained Ekin values excluded clearly a possibility of n-n correlations because the calculation gavea monochromatic kinetic energy of 3.8 MeV. The measured t-t fusion neutrons in the previous work5) showeda continuous energy spectrum with a maximum energy of 9 MeV, the shape of which was reasonably well
reproduced by a simple model assuming n-α particle
correlations. By combining the present results and theprevious conclusion, it is most probable that strong nα correlations are dominate in the three-particle decay
at the exit channel of t+t reactions.
References
1) T. Matsuzaki et al.: Nucl. Instrum. Methods Phys. Res.
A 465, 365 (2001).
2) T. Matsuzaki et al.: Nucl. Instrum. Methods Phys. Res.
A 480, 812 (2002).
3) T. Matsuzaki et al.: Phys. Lett. B 465, 74 (1999).
4) T. Matsuzaki et al.: RIKEN Accel. Prog. Rep. 38, 75(2004).
5) T. Matsuzaki et al.: Phys. Lett. B 527, 43 (2002).

83

RIKEN Accel. Prog. Rep. 39 (2006)

Dimuon measurement in Indium-Indium collisions at CERN/SPS
H. Ohnishi[Heavy-ion collisions, quark-gluon plasma, charm quark]
Under normal conditions, elementary particles,
quarks and gluons, are conﬁned inside a hadron according to Quark Chromodynamics (QCD) which describes the dynamics of elementary particles. However,QCD also predicts that under extreme conditions, suchas high temperature and/or high density, quarks andgluons will not be conﬁned in hadrons. These conditions are expected at just after the big bang or in thecore of the neutron star. This new state of matter,
which consists of many body systems of quark-gluon,
is called Quark-Gluon Plasma (QGP).
The use of high-energy heavy-ion collisions is one ofthe possible ways of creating nuclear matter with highenergy density. Normal nuclear matter may then undergo a phase transition to a QGP. The previously observed J/ψ suppression1) pattern in high-energy heavyion collisions at CERN-SPS seems to provide the ﬁrst
signal of color deconﬁnement. Simultaneously, an enhancement of dimuons in the Intermediate Mass Region (IMR, 1.5 < Mµµ < 2.5 GeV) is observed,2) withthe main contributions expected to be from the decays of charm mesons and dimuons from Drell-Yan processes. However, there have been no indications that
this color condensate subsequently leads to a medium
in thermal equilibrium, such as the QGP.
One of the relevant issues that the NA60 experimentintends to address is the origin of the enhancement of
IMR dimuons. Two hypotheses are proposed: the enhancement of charm meson production in heavy-ion
collisions, and thermal dimuon production from thecreated medium, which is a direct evidence of QGP
formation. To clarify this issue, we must be able toisolate the considerable yield of dimuons coming fromthe decays of charm mesons. Due to the long life timeof charm mesons, the origin of muons coming fromcharm meson decays will be oﬀset from the primaryvertex. Therefore, we need to perform secondary vertex measurements that provide approximately 50 µm
resolution. To achieve the above requirement, the vertex telescope (VERTEL) is installed just after the target to track all produced particles with high precision.
The VERTEL consists of a 16-plane tracking telescopein a 2.5 T magnetic ﬁeld, built from radiation tolerant silicon pixel detectors developed for the ALICE
experiment at CERN-LHC. The performance of the
VERTEL was seriously investigated and the track oﬀset resolution of the muon was achieved around 50 µm.
The experimental data of oﬀset distribution taking
into account the error for the tracking in the VERTEL (weighted oﬀset) are shown in Fig. 1. Note thatdata are the same for the left and right ﬁgures. This

84

distribution is then ﬁtted with a superposition of the
expected weighted oﬀset distributions for prompt andcharm meson decay contributions. The shape of theprompt sample contribution is evaluated with the measured J/ψ and φ oﬀset distributions. On the other
hand, the shape of the oﬀset distribution produced byMonte-Carlo simulation is used for the charm meson
decay contribution.
The left ﬁgure in Fig. 1 shows the results of the ﬁtwith the prompt contribution normalized to the expected Drell-Yan yield and the charm meson decay
contribution left free. The ﬁt result indicates that the
expected distribution with this parameterization is too
ﬂat to describe the data. As a next step, we try to
ﬁt the data with the normalizations of both promptand charm meson decay contributions as free parameters. The result is shown in the right ﬁgure of Fig. 1.
This result is in good agreement with the data with acharm meson decay contribution compatible with the
expected results, but requires two times more prompt
contribution from the expected prompt yield. This result indicates that 1) there is an excess in IMR dimuonsand 2) the source of the excess is due to the enhancement in the prompt dimuon. However, enhancement of
the Drell-Yan yield is not observed.3) Therefore, theseresults indicate that the source of the IMR dimuon enhancement is not from known sources such as the DrellYan or charm meson decay but rather from unknown
sources such as a signal from thermal dimuons whichis expected as a direct signal from QGP. The detailed
evaluation of systematic uncertainty is in progress.

Fig. 1. Fit results of IMR dimuon weighted oﬀset spectrum(left) with normalization of charm meson decay contribution as free parameter and (right) with normalizationof charm meson decay and prompt contributions as freeparameters.

References
1) M. C. Abreu et al.: Eur. Phys. J. C 39, 335 (2005).
2) M. C. Abreu et al.: Eur. Phys. J. C 14, 443 (2000).
3) R. Arnaldi et al.: Proc. Quark Matter 2005, Budapest,
Hungary, 2005-8, to be published.

RIKEN Accel. Prog. Rep. 39 (2006)

Eigenvalues of the time-delay matrix in overlapping resonances
I. Shimamura, J. F. McCann,∗1 and A. Igarashi∗2
A scattering resonance is associated with rapid increase in the phase shift δ(E) with the scattering energy E. For an isolated resonance with a single open
channel, δ(E) may be parameterized by the resonanceposition E1 and width Γ1 by the Breit-Wigner formulatan[δ(E) − δb (E)] = −(Γ1 /2)(E − E1 ),(1)where the background phase shift δb (E) varies slowly
with E. A calculated phase shift may be ﬁtted to (1)to obtain the parameters E1 and Γ1 as well as δb (E).
When N (>1) open channels are coupled to a resonance, the N -by-N S matrix, which is an extensionof the single-channel formula S(E) ≡ exp(2iδ), shows
rapid variation with E. This variation is parametrized
not only by E1 and Γ1 but also by partial widths
Γ1i (i = 1, · · · , N ) representing the decay into channels i, as well as the background S matrix, Sb (E).
Parameterization of the S matrix seems impractical when many channels, i.e., many ﬁtting parameters{Γ1i } and E1 , are involved. However, Eq. (1) still applies to multichannelcases if Γ1 is understood as thetotal width i Γ1i and if δ(E) and δb (E) are taken to
be the sum of the eigenphases δi (E) and the sum of the
background eigenphases δb,i (E);1) δi (E) are deﬁned bywriting the diagonal elements of the diagonalized S
matrix as exp(2iδi ), and δb,i (E) similarly deﬁned byusing Sb (E). This result is quite convenient for multichannel resonance analysis by parameter ﬁtting.
Smith2) deﬁned another useful matrix, the lifetime(or time-delay) matrix Q(E), as an extension of thetime delay in single-channel scattering.3) He provedthat Q(E) = ih̄S(dS † /dE), where S † is the Hermitian
conjugate of S. The diagonal elements Qii have thephysical meaning of the average time delay, over all
exit channels, starting from the initial channel i.
The diagonal sum or the trace of the time-delay matrix, Tr Q, is related to the eigenphase sum δ(E) by
2h̄(dδ/dE) = Tr Q(E)(2)

if Eq. (1) is valid. In fact, Eq. (2) is a very general
theorem valid for the S(E) matrix or the eigenphasesum δ(E) of any form, as we proved recently.4)
In this work, we study the properties of Q(E) andδ(E) for multichannel overlapping resonances at energies Eν with widths Γν . We prove the relation
Tr Q(E) =Gν (E) + 2h̄(dδb /dE),(3)
where Gν (E) = (h̄Γν )/[(E − Eν )2 + (Γν /2)2 ]. The
equivalent integral form of the relation is∗1∗2

Department of Applied Mathematics and Theoretical
Physics, Queen’s University Belfast, UK
Department of Applied Physics, Miyazaki University

δ(E) = −arctan[(Γν /2)/(E − Eν )] + δb (E). (4)These results are quite useful in the analysis of overlapping resonances by parameter ﬁtting.
For an overlapping double-resonance with a slowly
varying background, all eigenvalues qi (E) of Q(E) arenearly zero, except for two, which take a formq± ≡ (G1 + G2 )/2 ± [(G1 − G2 )2 + 4βG1 G2 ]1/2/2, (5)where β (0≤β≤1) represents the strength of the interaction between the two overlapping resonances. Equation (5) shows a typical avoided crossing between two
Lorentzian proﬁles. The two limiting cases of (5) areβ→0:q± → Gi (E), i = 1, 2,

where the two Lorentzians appear independently, andβ→1:q+ → G1 (E) + G2 (E), q− → 0,

where q+ is the mere sum of the two Lorentzians.
We show an example of Ps− consisting of an electron e− and a positronium Ps, an electron-positron system (Fig. 1). Multichannel continuum states were calculated from hyperspherical coupled-channel (HSCC)
equations; see Ref. 5 for detail. The two extreme overlapping cases are seen: (a) Strong avoidance for thesymmetry 1 Po just below the threshold Eth = −0.0278
a.u. for the breakup into e− + Ps(n=3) and (b) weak
avoidance for symmetry 1 De just above Eth .

Fig. 1. Two largest eigenvalues qi of Q(E) for Ps− . Solid
curves: HSCC. Broken curves: fitting of Eq. (5). (a)1 oP . β = 0.95. The curve for q1 is indistinguishable
from the solid curve. (b) 1 De . β = 0.10.

References
1) A. U. Hazi: Phys. Rev. A 19, 920 (1979).
2) F. T. Smith: Phys. Rev. 118, 349 (1960).
3) E. P. Wigner: Phys. Rev. 98, 145 (1955).
4) A. Igarashi and I. Shimamura: Phys. Rev. A 70, 012706(2004).
5) A. Igarashi, I. Shimamura, and N. Toshima: New J.
Phys. 2, 17 (2000); A. Igarashi and I. Shimamura: J.
Phys. B 37, 4221 (2004).

85

RIKEN Accel. Prog. Rep. 39 (2006)

Measurement of resonant coherent excitation for channeling Li-like
Fe ions using silicon surface barrier detector target
Y. Nakai, T. Ikeda, Y. Kanai, T. Kambara, N. Fukunishi, Y. Nakano,∗1 C. Kondo,∗2
T. Azuma,∗1 K. Komaki,∗2 and Y. Yamazaki∗2
When the energy diﬀerence between two electronic
states of an ion channeling through a crystal matcheswith one of the frequencies of the periodic crystal ﬁeld,
the ion is resonant-coherently excited. This excitationis referred to as “resonant coherent excitation (RCE).”
Many RCE experiments have been performed to date.
Nevertheless, we have recently observed RCE phenomena of an outer shell electron of systems with three ormore electrons for the ﬁrst time to our best knowledge
using 83 MeV/u Fe23+ ions.1) In the observation of the2s electron RCE to the n = 3 states, it was found that
the RCE corresponding to optically forbidden transitions can be seen as well as optically allowed transitions, where the transitions to the 3s1/2 , 3d3/2 and3d5/2 states are optically forbidden and the transitions
to the 3p1/2 and 3p3/2 states are optically allowed.
We have been considering two possible reasons forthe observation of the optically forbidden transitions
as well as optically allowed transitions. (1) The transitions from the 2s state to the 3s and 3d states arecaused by transitions via the 3p component in the
Stark-mixed 3s and 3d states. (2) Pure optically forbidden transitions with a large momentum transfer
have to be considered. These eﬀects are very small orzero at the channeling center. However, these two effects become more important with increasing distancefrom the channel center.
To obtain information on the distance where thetransitions to the 3s and 3d states occur, we useda silicon surface barrier detector (SSD) target. Thismethod has already been used for RCE measurement of 390 MeV/u hydrogen-like Ar ions.2) The energy deposit to the target crystal from channeling ionsstrongly depends on their oscillating orbits. The energy deposit increases with the amplitude of the oscillating orbit. Therefore, coincidence measurement between the ﬁnal charge states of Fe ions and the energy
deposit in the SSD gives information on the distance
where the transitions to the 3s and 3d states occur.
An SSD target of approximately 10 µm thickness wasvertically mounted so that the beam direction was near
the [001] axis of the silicon crystal. The ions emerging from the SSD were deﬂected by an analyzing magnet located downstream of the SSD target to separate
the ﬁnal charge states. A two-dimensional positionsensitive detector (2D-PSD) was located 8 m downstream of the analyzing magnet, which detected Li-like,He-like, H-like and bare ions.
∗1
∗2

86

Department of Physics, Tokyo Metropolitan University
Institute of Physics, University of Tokyo

The fraction of Li-like ions ionized solely through
RCE, p(θ, ∆E) = 1 − f (θ, ∆E)/fnon-res (∆E),2) isshown in Fig. 1 as a function of θ and ∆E, whereθ is the rotation angle from the [001] axis and ∆E isthe energy deposit in the SSD target. f (θ, ∆E) is thesurvival fraction of Li-like ions for each θ and ∆E.
f = N (Li-like)/[N (Li-like) + N (He-like)+ N (H-like) + N (bare)]Here, N is the number of Li-like, He-like, H-like andbare ions emerging from the SSD. fnon-res (∆E) isthe average survival fraction of Li-like ions in the oﬀresonance region.
In the low ∆E region, i.e., near the channeling center, only optically allowed transitions, 2s-3p, have alarge p(θ, ∆E). Increasing ∆E, i.e., increasing the distance from the channel center (increasing the amplitude of the oscillating orbit), the p(θ, ∆E) of the optically forbidden 2s-3s transition rapidly increases. On
the other hand, those of the optically forbidden 2s-3dtransitions do not increase so rapidly.

Fig. 1. Fraction of Li-like ions ionized solely through RCE,p(θ, ∆E).

References
1) Y. Nakai et al.: Nucl. Instrum. Methods Phys. Res. B
230, 784 (2005).
2) T. Azuma et al.: Phys. Rev. Lett. 83, 528 (1999).

RIKEN Accel. Prog. Rep. 39 (2006)

Ni-ion-induced charge collection measurements of
SiC Schottky barrier diodeC. Kamezawa,∗1 Y. Satoh,∗1 N. Ikeda,∗1 S. Kuboyama,∗1 O. Shimada,∗2 H. Otomo,∗2
H. Ohira,∗2 N. Inabe, and M. Kase
Silicon carbide (SiC) is one of the candidates for the
next-generation semiconductor materials. SiC devices
can be possibly operated under harsh environments
such as at very high temperature and in strong electricﬁelds, as compared with Si devices.
In electronic devices, there are two types of radiation
damage for semiconductors: one is caused by atomic
displacement, and the other by ionization. However,
SiC devices are inherently resistant to radiation eﬀects,
because the charge generated by radiations is small.
Most particular and well known among the above
damages is the destructive breakdown of semiconductor devices, called single-event burnout (SEB). For
space applications, there is a need to prevent the occurrence of SEB, which is caused by high-energy particles
of diﬀerent types and energies in space.
The SEB for Si devices is essentially triggered by aplasma column along the incident ion track in the depletion layer, e.g., epitaxial layer in a unipolar device,where plasma density is calculated from the electronhole pair generation energy and linear energy transfer(LET) of the incident particle. However, the correlation between the energy loss of high-energy particles and damage in SiC materials remains unclear. In
this work, we have performed a charge collection measurement of an Ni-ion strike to understand its physicalmechanism for future space applications of SiC devices.
The SiC Schottky barrier diode used in this work
as a simple SiC device was the commercially available Inﬁneon SDP06S60, which has an epitaxial layerof ∼6 µm. The properties of irradiated Ni ions areshown in Table 1. The Ni ion has a suﬃcient projection range to pass through the active region of thesample device, provided the mold material on the chipsurface is removed and irradiation is performed with anormal incidence from the Schottky contact surface tosubstrate.
Figure 1 shows the schematic diagram of the irradiation system for SiC-Schottky barrier diodes. The
electron-hole pairs generated by incident Ni ions werecollected by adjusting applied bias voltage. To investigate the behavior of the generated charges, a chargesensitive preampliﬁer, the ORTEC 142B, was used tomeasure charge collection spectra.
Figure 2 shows the collected charge spectra of a sample as a function of reverse bias voltage. Here, thepeak of the collected charge is shifted with an increase∗1∗2

Institute of Aerospace Technology, Japan Aerospace Exploration Agency
Ryoei Technica Corporation

Table 1. Property of Ni ion used in this study. LET andrange derived using software of SRIM 2003.

Fig. 1. Schematic diagram of irradiation and measurement
system.

Fig. 2. Charge collection spectra obtained by Ni ion irradiation as function of reverse bias voltage.

Fig. 3. Charges collected at peak of each spectrum at room
temperature and 70◦ C.

in bias voltage and an anomalously large charge collection with an excess charge collection eﬃciency of 100%
is observed at a higher bias voltage.
To clarify the mechanism of the anomalously large
charge collection, the charge at the peak of each spectrum was taken at room temperature and 70◦ C, as
shown in Fig. 3. In this ﬁgure, the charge collection
was suppressed by a temperature increase at higher
voltages, although it was larger at lower voltages. This
result suggests that the anomalously large charge isbasically produced by an electron avalanche in the
Schottky barrier, because the temperature increase reduces carrier mobility, which is sensitive to the yieldof electron-hole pairs generated in the barrier.

87

RIKEN Accel. Prog. Rep. 39 (2006)

Elastic waves from swift heavy-ion irradiations on solids
T. Kambara, K. Kageyama,∗ Y. Kanai, T. M. Kojima, Y. Nakai, A. Yoneda, and Y. Yamazaki
We have studied sound waves generated by fastheavy-ion irradiations on solid samples at the RIKEN
Ring Cyclotron.1–3) Samples of various solids havebeen irradiated with short-pulse beams of 3.8-GeV Ar
ions and 3.54-GeV Xe ions and sound waves at ultrasonic frequencies have been observed on the surface at
diﬀerent directions from the beam spot. The angulardependence of the sound waveform, called radiation
pattern, reﬂects the mechanical motion of the matterat the sound source, where stress and strain are generated by energy deposition from the ions.
We have observed marked diﬀerences in radiation
patterns between the Ar and Xe irradiations on thesame material. The waveforms from the Ar-ion irradiation are almost independent of the sound-wave direction, and contain only an isotropic compressional wave
(P wave) generated at the end of the ion range. On
the other hand, the 3.54-GeV Xe-ion irradiation generates more complicated waveforms, which are strongly
dependent on the sound-wave direction and contain ashear wave (S wave) in addition to the P wave. The
diﬀerence in waveforms between the Xe and Ar ionscan be described as the diﬀerence of the mechanicalboundary condition of the sound source due to diﬀerent ion ranges in materials.
The purpose of the present experiment was to study
the extent of the sound source through the dependenceof the waveform on the ion-penetration depth. The
experimental setup was almost the same as that reported previously.1) An Ar beam was modulated tosingle bunches at a rate of 109 Hz, each of which wasapproximately 3-ns long and contained ions in the order of 103 . The sample was a 10-mm-thick, 40 mm ×
40 mm plate of polycrystalline aluminum. Sound signals were detected with a piezoelectric sensor attachedto the sample at the center of the back side of thebeam spot. The sample and sensor were mounted on aremote-controlled movable feedthrough so that diﬀerent points on the sample were irradiated. The beamenergy on the sample was adjusted with a degraderwhich was a 3- or 4-mm thick aluminum plate inserted
in front of the sample.
Figure 1 shows sound waveforms from irradiation
with 3.8-GeV Ar ions (a) without a degrader, (b) withthe 3-mm-thick degrader, and (c) with the 4-mm-thickdegrader. According to the TRIM code,4) the range of
3.8-GeV Ar ions in Al is estimated to be 4.24 mm, sothat the actual ranges in the sample are (a) 4.24 mm,(b) 1.24 mm and (c) 0.24 mm, respectively. For comparison, Fig. 1 (d) shows a waveform from the same
sample irradiated with 3.54-GeV Xe ions without a∗

88

Department of Mechanical Engineering, Saitama University

Fig. 1. Sound waveforms from Al irradiated with 3.8-GeV
Ar ions with degrader thicknesses of (a) 0 mm, (b) 3 mm
and (c) 4 mm, and (d) 3.54-GeV Xe ions without a degrader. On the right side are the distances between thesensor and the epicenter.

degrader where the estimated ion range is 0.29 mm.
The waveforms are averaged over up to 50 shots of ionbunches and normalized to 1000 ions. The graphs also
show beam-bunch patterns observed with a secondaryelectron monitor, and the origin of the time is set tothe arrival of the beam bunch. The distances of thesensor relative to the epicenter are indicated on theright side of the graphs. The solid and dashed lines
show the estimated arrival times of the direct P and
S waves, assuming the sound source at the end of theion range calculated with the TRIM code.
The radiation patterns of the Ar irradiation in
Fig. 1 (a-c) apparently depend on the length of theion range, and that with the shortest ion range (c) resembles that of the Xe irradiation (d) with a structure
along the expected arrival time of the S wave.
References
1) T. Kambara, K. Kageyama, Y. Kanai, T. M. Kojima,
Y. Nakai, A. Yoneda, and Y. Yamazaki: Nucl. Instrum.
Methods Phys. Res. B 193, 371 (2002).
2) T. Kambara: Nucl. Instrum. Methods Phys. Res. B
230, 601 (2005).
3) T. Kambara: Nucl. Instrum. Methods Phys. Res. B
245, 108 (2006).
4) 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. 39 (2006)

Synthesis of Au nanoparticles by GeV-ion irradiation
N. Maeda,∗ F. Hori,∗ T. Kambara, T. Abe, and A. Iwase∗
As metallic nanoparticles have some specific characteristics which are not observed in bulk metallic materials, they have been applied for various uses in someindustrial fields. It is well known that γ-ray irradiation can reduce metallic ions in aqueous solutions andhas been used for the synthesis of metallic nanoparticles1) . However, electron or energetic ion irradiation
has hardly been used for metallic nanoparticle synthesis. In this study, we have produced Au particles byirradiating aqueous solutions with swift heavy ions.
Samples used in the present experiment were dilute aqueous solutions with 0.5 m mol/l Au ions and
0.4 m mol/l Polyethylene Glycol Monostearate as surfactants. NaAuCl4 2H2 O was chosen as a precursor of
Au3+ ions. Irradiation was performed at E5B beamline of the RIKEN ring cyclotron accelerator. The
samples were irradiated with 1.6 GeV full-stripped C
ions. The dose rate was approximately 2 Gy/sec andthe absorption doses were 300, 600, 900 and 1200 Gy.
After C-ion irradiation, the optical absorption spectra of each solution were measured using an ultravioletvisible spectrophotometer (UV-vis). Then, nanoparticles produced by the irradiation were directly observed
by a transmission electron microscope (TEM) to determine their shapes and sizes.
Figure 1 shows the results of UV-vis measurements

for irradiated samples. Large peaks appear at around
530 nm. These peaks correspond to the absorption
by surface plasmon of the produced Au nanoparticles.
The appearance and growth of the peak indicate that
C-ion irradiation reduces Au3+ ions in the aqueous solution and produces Au nanoparticles. Figure 2 shows
the TEM images of Au particles produced by C-ion
irradiation. Figure 3 shows the size histogram of Au
nanoparticles. The mean diameter value is approximately 20 nm, and the size of the Au particles is widelydistributed from 9 nm to 50 nm. These results indicatethat swift heavy-ion irradiation can be used for thesynthesis of metallic nanosized particles.

Fig. 2. TEM images of Au nanoparticles produced by
1.6 GeV C-ion irradiation.

Fig. 3. Particle size histogram of Au nanoparticles.

Reference
Fig. 1. UV-vis absorption spectra for aqueous solution irradiated with 1.6 GeV C ions.

∗

1) T. Kinoshita, S. Seino, Y. Otome, Y. Mizukoshi, T.
Nakagawa, T. Nakayama, T. Sekino, and K. Niihara:
Mater. Res. Soc. Symp. Proc. 877E, S6.30.1 (2005).

Department of Materials Science, Osaka Prefecture University

89

RIKEN Accel. Prog. Rep. 39 (2006)

Observation of hyperfine field on 17 N nucleus
at P1 center in diamond
T. Arai,∗ M. Uchida,∗ H. Ueno, D. Kameda, M. Takemura,∗ A. Yoshimi, T. Haseyama,
K. Shimada,∗ D. Nagae,∗ G. Kijima,∗ S. Suda,∗ T. Inoue,∗ K. Takase,∗ and K. Asahi
Nuclear spins in a diamond are known to show exclusively long relaxation times,1) suggesting a possibility
for their applications in nuclear spin-based quantum
information technology, and in condensed matter andnuclear structure physics. In particular, an unpaired
electron accompanied by each of impurity nuclear spinsin a diamond may enable dynamic nuclear polarizationand nuclear spin manipulation through hyperﬁne interactions. The P1 center in a diamond is one of the defectcenters which accompany such an unpaired electron.
The P1 center consists of a nitrogen atom substituting
for a carbon atom2) as shown in Fig. 1 (a). Because
a nitrogen atom has ﬁve 2s2p electrons, an unpaired
electron resides in the vicinity of nitrogen. A previous ESR study suggests that the unpaired electron isbound in one of the four antibonding orbitals between
the nitrogen and surrounding carbon atoms, from theobserved hyperﬁne splittings of an ESR line. However,such hyperﬁne ﬁelds on the extremely dilute nuclear
spins are very diﬃcult to observe by the conventional
NMR technique. In this study, we measured the hyperﬁne ﬁeld on a 17 N nucleus by the β-NMR methodby implanting spin-polarized radioactive 17 N nuclei.
A beam of spin-polarized 17 N was produced from thefragmentation of 18 O projectiles at 70 MeV/nucleon on
a 500-µm-thick Nb target.3) The 17 N fragments were
implanted in a diamond stopper at room temperature.
The stopper, 10 × 14 mm2 in area, was made up of 35“tiles” (2 × 2 × 1 mm3 ) of type Ib synthetic diamond.
A static magnetic ﬁeld B0 = 715 mT was applied inthe [100] direction. Thus, all of the four N-C bonds
were inclined at an angle of θ = 54.7◦ from the appliedﬁeld.
The hyperﬁne coupling constant A has been determined from the ESR study,4) as A2 (θ) = A2 cos2 θ +A2⊥ sin2 θ with a considerable anisotropy, A /(ge µB ) =4.085 mT and A⊥ /(ge µB ) = 2.918 mT for a 14 N nuclear spin. In a strong ﬁeld limit of the external ﬁeld
ge µB B0  A, the nuclear spin transition takes placeat resonance frequencies given by





A(θ)

(1)
hν0 = g17 µN B0 +ms  ,
g14 µN
where µB and µN denote the Bohr magneton and nuclear magneton, and ge and gn (= g14 , g17 ) are theg-factors for the electron and nucleus (14 N or 17 N), respectively. The second term in the bracket represents
the hyperﬁne ﬁeld Bhf exerted on the 17 N nuclear spinby the electron in a substate ms , and is calculated as
Bhf = ±15.3 T for ms = ±1/2 at θ = 54.7◦ .
An oscillating magnetic ﬁeld B1 was applied in the
direction perpendicular to the B0 ﬁeld, to reverse 17 N
nuclear spins by the adiabatic fast passage (AFP)
technique. Inserting the g-factor for 17 N, |g17 | =0.704 ± 0.004,3) ν0 is calculated as ν0< = 78.3 MHzand ν0> = 85.9 MHz, corresponding to ms = −1/2 andms = +1/2. To cover these two frequencies, the frequency for the B1 ﬁeld was swept from 74 to 90 MHz in
60 ms. The observed change in the up-down asymmetry of the β-rays is shown in Fig. 1 (b). A signiﬁcant
asymmetry change of 0.14 ± 0.04% is observed.
The present crude β-NMR result indicates that thestrength of the hyperﬁne ﬁeld on 17 N at the P1 center
takes a value between 13.1 and 17.5 T, in agreementwith the structure of the P1 center previously proposed.5) The observed size of the β-asymmetry change
indicates that about 1/4 of the implanted N atoms
stop in substitutional sites in a diamond, based on acomparison with the observed asymmetry change in agraphite stopper. The present ﬁnding implies the possibility that the spins of unstable nuclei may be polarized by implanting them in a diamond stopper by the
dynamic polarization technique, and (stable) nuclear
spins may be implanted externally to form a quantum
information system.
References

Fig. 1. (a) Crystalline structure of P1 center in diamond.
(b) Obtained asymmetry change for 17 N in diamond
under hyperfine field.
∗

90

Department of Physics, Tokyo Institute of Technology

1) E. C. Reynhardt and G. L. High: J. Chem. Phys. 109,
4090 (1998).
2) J. H. N. Loubser and J. A. Van Wyk: Rep. Prog. Phys.
41, 1201 (1978).
3) H. Ueno et al.: Phys. Rev. C 53, 2142 (1996).
4) S. Zhang et al.: Phys. Rev. B 49, 15392 (1994).
5) W. V. Smith et al.: Phys. Rev. 115, 1546 (1959).

RIKEN Accel. Prog. Rep. 39 (2006)

Online TDPAC measurements with the 19 F probe
implanted in metal oxides
W. Sato,∗1 H. Ueno, Y. Itsuki,∗1 A. Yoshimi, K. Shimada,∗2 D. Kameda, D. Nagae,∗2 G. Kijima,∗2
M. Takemura,∗2 T. Arai,∗2 S. Suda,∗2 T. Inoue,∗2 K. Takase,∗2 A. Shinohara,∗1
Y. Kobayashi, and K. Asahi
Online time-diﬀerential perturbed angular correlation (TDPAC) spectroscopy is an eﬀective method forextending the study ﬁelds in materials sciences because
it enables the introduction of short-lived parent nuclei of PAC probes in samples by the RI beam production technique. In order to apply this method in
condensed matter physics and chemistry, we have recently developed a new online TDPAC method at the
RIKEN Accelerator Research Facility employing the19
F probe, the β-decay product of 19 O.1) As the ﬁrst
application of this method to oxides, an online experiment was recently performed for a polycrystalline perovskite manganite La0.7 Ca0.3 MnO3 , which is known toshow a colossal magnetoresistance (CMR) eﬀect,2) forthe purpose of providing insight into the mechanism of
the magnetic phenomenon. We here brieﬂy report the
preliminary results of the experiments.
Polycrystalline La0.7 Ca0.3 MnO3 was synthesized bya conventional solid-state reaction from stoichiometricamounts of La2 O3 , CaCO3 , and MnO2 . The formationof a single phase was corroborated by a powder X-ray
diﬀraction measurement, and magnetization as a function of temperature was investigated. The obtained
crystallographic and magnetic properties were foundto show good agreement with those in literature.3,4)
The powdered sample was pressed into a cylindricalaluminum holder with a size of 12 mmφ×5 mm so thatmost of the incident beam can be stopped in it. The
holder was attached to the tip of the cold head of acryostat equipped with a temperature controller. The
primary 22 Ne ions were accelerated to 110 MeV/u ata beam intensity of 250 pnA. A variety of radioactive
nuclides were formed at the Be production target bya projectile-fragmentation reaction, and the secondary
beam of interest, 19 O, was separated by the RIKEN
projectile-fragment separator.5) A well-focused pulsed
beam of 65 MeV/u was implanted in the sample disc,and online TDPAC measurements were performed onthe (1357–197) keV cascade γ rays. In order to obtainbetter statistics of coincident events, we used sixteen
BaF2 scintillators and arranged them in four independent detector planes.

∗1∗2

A preliminary TDPAC spectrum of 19 F implanted in
the polycrystalline La0.7 Ca0.3 MnO3 is shown in Fig. 1.
The time-variant directional anisotropy A22 G22 (t),which is given by a simple arithmetic operation as
A22 G22 (t) =2 [N (π, t) − N (π/2, t)],
N (π, t) + 2N (π/2, t)(1)

is plotted as a function of the time interval, t, between
the cascade γ rays. Here, N (θ, t) denotes the numberof coincident events observed at an angle, θ. An oscillatory structure is seen in the spectrum. The structure
is considered to originate from the hyperﬁne interaction with the internal magnetic ﬁeld and/or the electric
quadrupole interaction with the extranuclear charge
distribution. To obtain further microscopic information, investigation of the temperature dependence of
the TDPAC spectra is needed. Precise data analysis is
now in progress.

Fig. 1. TDPAC spectrum of 19 F implanted in powder
La0.7 Ca0.3 MnO3 at 200 K.

References
1) W. Sato et al.: J. Radioanal. Nucl. Chem. 255, 183(2003).
2) A. P. Ramirez: J. Phys. Condens. Matter 9, 8171
(1997).
3) V. Chechersky et al.: Phys. Rev. B 59, 497 (1999).
4) H. Y. Hwang et al.: Phys. Rev. Lett. 75, 914 (1995).
5) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).

Graduate School of Science, Osaka University
Graduate School of Science and Engineering, Tokyo Institute of Technology

91

RIKEN Accel. Prog. Rep. 39 (2006)

Eﬀects of proton beam irradiation of chalcopyrite-type compound
semiconductor solar cell material
K. Yoshino,∗1 M. Yamauchi,∗2 and K. Morimoto
I-III-VI2 chalcopyrite semiconductors have been attractived for solar cell applications because of theirdirect-bandgap and high-optical-absorption. Indeed,
CuInGaSe2 solar cell energy conversion eﬃciencies ofmore than 19.5% have been reported.1) Furthermore,radiation damages of the CuInGaSe2 are very small incomparison with other solar cell materials such as polySi, single Si, amorphous-Si and InGaP.2) On the other
hand, Ag-III-VI2 materials, such as AgInSe2 , are also
promising candidate materials for solar cells. AgInSe2
has a bandgap energy of 1.20 eV3) and a melting pointof 780◦ C, which are even better than CuInSe2 for solar
cell applications. An eﬃciency of 7.5% was reported
for a solar cell which used a AgInSe2 absorber on pAgInSe2 /n-CdS.4) However, little is known about theproperties of AgInSe2 thin ﬁlms.
In our previous study,5) AgInSe2 thin ﬁlms wereprepared on a quartz glass substrate by evaporation
method. After the evaporation, the samples were annealed at 600◦ C for 10 min. in an Ar atmosphere.
Single-phase AgInSe2 , with a (112) orientation waspresent in the sample annealed at 600◦ C by X-ray
diﬀraction (XRD). Measured lattice constant of thea-axis was close to the JCPDS value; however, the caxis was larger than that of the JCPDS value. TheAgInSe2 ﬁlm has n-type conductivity with a resistivityof 0.14 Ω cm, a carrier concentration of 2.5 ×1018 cm−3and a mobility of 20 cm2 (V s) −1 .
Here, a proton beam irradiation of the AgInSe2 ﬁlms
was carried out using the AVF cylotron in RIKEN to
obtain information on irradiation damages. The energies of the proton were from 0.8 to 4 MeV at a dose of
1 ×1015 cm−2 . The ranges of the proton are from approximately 10 to 100 µm. Protons passed through thesample because the thickness of the sample is approximately 1 µm. Hall measurements were carried out atroom temperature using the Van der Pauw method forelectrical characterization. Gold was used as an ohmic
contact.
Figure 1 shows resistivity and mobility as functionsof proton energy. Resistivity is constant at protonenergies less than approximately 3 MeV and increases
above 3 MeV. From the XRD measurements, the values of full width at half maximum of a (112) peakincrease with increasing proton energy. This meansthat grain sizes decrease with increasing proton energy.
Therefore, it is deduced that the decrease in mobility is
∗1
∗2

92

Department of Electrical and Electronic Engineering, University of Miyazaki
Department of Applied Physics, University of Miyazaki

Fig. 1. Resistivity and mobility as functions of proton energy. White square and black circle indicate mobility
and resistivity, respectively. A 0 MeV proton energy
indicates nonirradiation.

due to the decrease in grain sizes. On the other hand,carrier concentration slightly increases with increasing
proton energy. All irradiation samples have n-typeconductivity. The conduction types are not changedby the proton irradiation. A type of carrier in thenonirradiated sample has already been reported as Sevacancy.5) Therefore, it is assumed that the increasein carrier concentration by proton irradiation is due tothe increase in defects of Se-vacancy and/or interstitialhydrogen.
References
1) M. A. Contreras, K. Ramanathan, J. Abushama, F.
Hasoon, J. Keane, D. L. Young, B. Egaas, and R. Noufi:
Prog. Photovolt. Res. Appl. 13, 209 (2005).
2) M. Imaizumi, T. Sumita, S. Kawakita, K. Aoyamna, O.
Anzawa, T. Aburaya, T. Hisamatsu, and S. Matsuda:
Prog. Photovolt. Res. Appl. 13, 93 (2005).
3) B. Tell, J. T. Shary, and H. M. Kasper: J. Appl. Phys.
43, 2469 (1972).
4) P. P. Ramesh, O. M. Hussain, S. Uthanna, B. S. Naidu,
and P. J. Reddy: Mater. Lett. 34, 27 (1997).
5) H. Matsuo, K. Yoshino, and T. Ikari: Submitted toPhys. Stat. Sol.

RIKEN Accel. Prog. Rep. 39 (2006)

Ultra-short-pulse continuum of ion track and its universality
K. Kimura, M. Koshimizu,∗ H. Ryuto, K. Asai,∗ and M. Kase
Time-integrated luminescence spectra of ion-irradiated solid material are used to be mostly combinationsof luminescence spectra known in photo- or electron
irradiation, in spite of expectation that vast deposit
energy could produce something new. Known spectra
are due to self-trapped excitons (STE), excited defector impurity centers, and/or recombination of electron
and shallow trapping of holes. However, time-resolved
measurements with a resolution of about 100 ps enable us to obtain quite diﬀerent results. Some decay rates are enhanced extraordinarily. Moreover, a
new ultra-fast luminescence continuum (UFLC) appears in time-resolved luminescence spectra within a
few tens ps after an ion impact. Since UFLC was ﬁrst
observed for alumina,1) it has been observed universally in all the heavy-ion irradiated insulator crystals
except for diamonds. The luminescence can be characterized as follows2) : UFLC covers a wavelength region from vacuum ultraviolet to visible. Its eﬃciency
is largely dependent on the atomic number of a projectile ion, i.e. excitation density. The luminescenceeﬃciency increases super linearly in many cases withincreasing excitation density. This means that the precursors for luminescence interact multiply with eachother. However, known excited states cannot be theprecursors, which can be proved by kinetics using theshape of the decay curve. In addition to this, large
chemical-composition dependence was observed. Also,
the continuum has structures and their peaks appear
at similar positions to those due to the known excitedstates although the UFLC is broadened. On balance,
the precursors aforementioned may be electrons staying at higher quantum levels under potential of holes.
A number of electrons are ejected radially from cylindrical region along the track core, and return back to
the track core after thermalization.2) The density ofthe electrons is so high that the interaction compels
the electron-hole pairs strongly to release excess energy. The releasing is considered to occur not only
via the phonon networks by bonds surrounding eachhole but also via photo-emissions by the interaction
between electron-hole pairs. At extremely high density, the emission may occur through the interactions
among electrons near continuum levels and in the intermediate way of hole-trapping. We consider that thisis UFLC. In case of alkali halides with large luminescence eﬃciencies, the hole is the neutral halogen atomwhich cannot have ionic bonds. This mechanism looks
to explain the experimental results well. Now, we call
UFLC track-luminescence continuum (TLC).
∗

Department of Applied Chemistry, Graduate School of Engineering, Tohoku University

Figure 1 gives two experimental results at RILAC:(a) shows TLC spectra of KI single crystal irradiated by 2 MeV/u Xe ions at 296 K. All luminescencebelongs to TLC because STEs, being the principal
sources of luminescence, cannot survive at this temperature. TLC has a structure comprised of two peaks
and one shoulder. By photolysis near 4.2 K, STEs luminescence appears at I and II, but not at III. It is
known that there are three types of STEs due to I,
II, III but each alkali halide misses one or two STEsof the three. These missing STEs are virtual ones anticipated from comparisons of spectral peak positionsof every STE.3) The missing may mean that potential
is too shallow to stabilize the electron into the potential minimum. However, TLC seems to break every
spectral missing of alkali halides. The second example, given in Fig. 1 (b), is for N-ion irradiated MgO
crystal at 3.3 K. This material is known to have evident free-exciton luminescence at 162.5 nm. TLC neartime 0 shows coexistence of a sharp free-exciton band
and TLC near 180 nm. In case of Xe-ion irradiation
with much larger energy density, TLC was increased
while the free-exciton band disappeared because theprocess for TLC precedes free-exciton formation. In
this case also, there is a proposal of shrunk STE at
180 nm though negligibly weak.4) The situation seems
similar to the previous spectral missing.

Fig. 1. (a) Time-resolved spectra of Xe-ion irradiated KI
single crystal at 296 K. Bars I, II, and III are actualand anticipated appearance positions of STEs at 4 K,
respectively. (b) Time-resolved spectra for N-ion irradiated MgO crystal at 3.3 K.

References
1) K. Kimura, J. Kaneko, S. Sharma, W. Hong, and N.
Itoh: Phys. Rev. B 60, 12626 (1999).
2) K. Kimura: Nucl. Instrum. Methods Phys. Res. B 212,123 (2003).
3) K. S. Song and R. T. Williams: in Self-Trapped Excitons, (Springer, Berlin, 1993), p. 168.
4) Z. A. Rachko and J. A. Valbis: Phys. Stat. Sol. (6) 98,
161 (1979).

93

RIKEN Accel. Prog. Rep. 39 (2006)

Temperature and excitation density dependence of ultrafast
luminescence of ion-irradiated α-alumina
M. Koshimizu,∗ K. Kimura, H. Ryuto, K. Asai,∗ and M. Kase
Fast processes occurring along an ion trajectory,
which are characterized by high-density electronic excitation and related processes such as interaction among
excited states at a high density or that between excitedelectrons and a lattice system, has been a subject ofintensive studies, because these processes should be
profoundly related to the formation of an ion track.
In particular, in insulators, the self-trapping of a holeor an exciton renders these processes even more complicated, and it is suggested that self-trapping may be
relevant to the formation of an ion track. However, thebehavior of the self-trapped holes (STHs) or excitons(STEs) is not well understood for high-density excitation, and the interaction among them should leadto the behavior which is entirely diﬀerent from thatfor low-density excitation. In this study, to investigate the temporal behavior of STHs or STEs underhigh-density excitation, we measured the time-resolved
luminescence spectra of α-alumina about which the relaxation of holes or excitons for low-density excitation
has been discussed by many researchers.1)
The measured sample was a single crystal of αalumina. The sample was irradiated with N, Ar, andXe ions having energies of 2.0 MeV/nucleon. Excitation density by projectiles increases with increasing
mass of the projectiles. Time-resolved luminescence
spectra were obtained by the single-photon counting
method.
Figure 1 shows the decay curves of luminescence observed under irradiation with N, Ar, and Xe with energies of 2.0 MeV/nucleon. In each case, the decay curve
cannot be ﬁtted with a single exponential function. In
addition, in the case of Xe irradiation, there exists a
fast component, which is distinctly diﬀerent from theFig. 1. Normalized decay curves of luminescence of αalumina irradiated with N, Ar, and Xe. For N and Ar
irradiation, the luminescence was observed at 172.7 nm,
for Xe irradiation, 170.1 nm.
∗

94

Department of Applied Chemistry, Graduate School of Engineering, Tohoku University

other components. This fast component is observedin a wide wavelength range, particularly longer than
200 nm, in contrast to the slow components. In addition, the decay rates of the slow components seem todepend on excitation density. It should be noted thatthe decay rates of these components are much higher
than those observed for electron irradiation, and luminescence occurs at approximately the wavelength ofluminescence due to STE.1)
Figure 2 shows the normalized decay curves of theluminescence of Xe-irradiated α-alumina at 170.1 nm
at diﬀerent temperatures. The decay rate of the fastcomponent seems to be independent of temperaturein the measured temperature range. In contrast, thedecay rate of the slow component markedly decreased
with increasing temperature from 3.3 K to 7.0 K, andreached the minimum at 15 K.
Because the decay rates of both the fast and slow
components depended on excitation density, the decay rates are certainly related to interactions among
excited carriers. The threshold-like behavior of theintensity of the fast component, along with the weaktemperature dependence, indicates that this component is related to the interaction between many ‘hot’
excited species accompanying lattice deformation similar to the STE, such as electron-hole plasma in semiconductors.2) The high decay rate is also explained bya large oscillator strength of such high-density excitedspecies.2) In contrast, the slow components may be related to the interaction of a few excited species, such as
STEs, with the lattice system, although it is necessary
to measure the decay curves in a wider temperature
range.

Fig. 2. Normalized decay curves of luminescence of Xeirradiated α-alumina at 170.1 nm at diﬀerent temperatures.

References
1) For review, see J. Valbis and N. Itoh: Radiat. Eﬀ. Deffects Solids 116, 171 (1991).
2) C. Klingshirn and H. Haug: Phys. Rep. 70, 315 (1981).

RIKEN Accel. Prog. Rep. 39 (2006)

Resonant electron capture and decay for N ionsusing metal microcapillary targets
Y. Iwai, Y. Kanai, Y. Nakai, T. Ikeda, M. Hoshino,∗1 H. Oyama, H. Masuda,∗2
K. Nishio,∗2 H. A. Torii,∗3 K. Komaki,∗3 and Y. Yamazaki
When a slow highly charged ion approaches a metal
surface, the ion resonantly captures target valence electrons into its excited states above the surface and forms
a multiply and highly excited state. To study the formation and decay of the excited state in the vacuum, X
rays emitted from 2.3 keV/u Nqi + (qi = 7) ions transmitted through a thin Ni microcapillary foil were measured using a high-resolution soft X-ray spectrometer.
X-ray intensity for each transition as a function of timeafter passing through microcapillaries was evaluatedby cascade simulation, and the initial state distribution was reconstructed.
Ions (2.3 keV/u N7+ ) are supplied by a 14.5 GHz
Caprice electron cyclotron resonance ion source in
RIKEN.1) The microcapillary target was ∼1 mm2 inarea with a thickness of ∼1 µm and had numerous
straight holes of ∼200 nm diameter.2) When the ions
impinge on the microcapillary target parallel to thecapillary axis, a part of the ions that captured electrons from the capillary wall can pass through thecapillary before hitting the capillary wall and multiply and highly excited ions are extracted in vacuum.3) The spectrometer consists of a concave grating and a charge-coupled device. Further details of
the spectrometer and methods of data analysis aredescribed below.4) X-ray spectra were taken at eight
points (td = 0.0–6.0 ns) downstream of the target along
the ion beam, where t d is the time after passing
through the target.
Figure 1 shows K X-ray intensities I(td :qi = 7) for
np - 1s (n = 2, 3) and 1s2p 1, 3 P - 1s2 1 S transitions as
a function of td . The half-lives of I(td < 1.5 ns) andI(td ≥ 1.5 ns) were ∼0.1 ns and ∼1 ns, respectively,
except for 1s2p 3 P - 1s2 1 S transition. The half-lifeof 1s2p 3 P - 1s2 1 S transition was almost constant at∼5 ns. This is consistent with the lifetime of 1s2p 3 P,
i.e., 4.9 ns.5)
The initial state distribution (P I (n, :qi )) of the ﬁrst
electron transferred was calculated by cascade simulation for hydrogen-like ions. The np - 1s and 1snp 1s2 transitions were calculated by adopting the eﬀective charges of qe = 7 and 6, respectively. The averagevalue of the initial state n-distribution was ∼qi + 1.5
and the full widths at the half maximum of the distributions were δn∼2. The average value agreed with
∗1
∗2
∗3

Department of Physics, Sophia University
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. Intensities for np - 1s (n = 2, 3) and 1s2p 1, 3 P 1s2 1 S transitions as function of time after passing
through microcapillaries. Lines are results of cascade
simulations considering Auger decay.

the prediction obtained using the classical over barriermodel (COBM).6) The trend of n-distribution agreed
with a report of the visible light spectroscopy.7) Combining the present result and the report, it was concluded that the average value of n-distribution in the
broad -distribution was almost constant.
I(td ≥ 1.5) was reproduced by P I (n, :qi ), howeverI(td < 1.5) was not reproduced. Then, according2
to COBM, the initial state distribution (P I (n, :qi ))of the second electron transferred was assumed to2
be P I (n, :qi ) ≈ P I (n, :qi − 1). The distribution
P A (n, :qi ) after the Auger decay of ion that captured
two electrons was calculated. The lines in Fig. 1 show
the result of the cascade simulation by the combination of P I (n, :qi ) with P A (n, :qi ). Considering theAuger decay, I(td < 1.5) was reproduced. The ionsthat passed the Auger decay were ∼50% of X ray emitting ions.
References
1) Y. Kanai et al.: Phys. Scr. T 92, 467 (2001).
2) H. Masuda et al.: Appl. Phys. Lett. 71, 2770 (1997).
3) S. Ninomiya et al.: Phys. Rev. Lett. 78, 4557 (1997).
4) Y. Iwai et al.: Nucl. Instrum. Methods Phys. Res. B
193, 504 (2002).
5) W. R. Johnson et al.: Adv. At. Mol. Opt. Phys. 35, 255(1995).
6) J. Burgdörfer et al.: Phys. Rev. A 44, 5674 (1991).
7) Y. Morishita et al.: Phys. Rev. A 70, 012902 (2004).

95

RIKEN Accel. Prog. Rep. 39 (2006)

Single- and double-electron capture processes
in slow N5+ -He collisions
Y. Miyamoto,∗1 M. Hoshino,∗1 Y. Kanai, K. Otsuki,∗2 Y. Nakai, M. Kitajima,∗3 H. Tanaka,∗1 and Y. Yamazaki
We have measured angle-resolved energy gain spectra of N5+ -He collisions at impact energies of 340,
490, 580, and 670 eV, using the crossed-beam apparatus at the beamline-BL2 in the Slow Highly Charged
Ion Beam Facility of RIKEN. The single- and doubleelectron capture processes in N5+ -He collisions havebeen studied intensively. However, most of thesestudies involved total cross section measurements,1)
except for a few partial cross section measurements
for single-electron capture with VUV photon emission spectroscopy.2,3) In particular, there has been nostate-selective measurement of double capture. Because angular distributions become more sensitive tothe shape of the interaction potentials with decreasing impact energy, state-selective angular distributions
are expected to provide information on the interaction
potentials for single- and double-electron capture processes. By analyzing data for double electron capture
in detail, the ﬁnal states reported for 670 eV last year4)
were identiﬁed as the states of N3+ (1s2 2p2 )(peak 1),
N3+ (1s2 2s3l)(peak 2), N3+ (1s2 2p3l)(peak 3 or peak 4)
and N3+ (1s2 2s4l)(peak 3 or peak 4).
Our purpose is to obtain the information on the
shape of potential curves for the N5+ -He system. However, it is diﬃcult to extract the shapes of interaction
potentials directly from experimental angular distribution. As the ﬁrst step, we calculate ab-initio adiabatic
potential and discuss whether this potential can qualitatively explain our experimental results or not. It issuﬃciently valuable to discuss the validity of such adiabatic potentials. In order to obtain the interaction
potentials between N(5−q)+ − Heq+ (q = 0, 1, 2), singly
and doubly excited conﬁguration interaction (CI) calculations were performed using Alchemy software empolying the 7s6p4d3f Gaussian orbitals and the 6s4p
Gaussian orbitals to guarantee the energy levels of the
N-ion and He-ion/neutral, respectively. In the CI calcultions, the 1s-orbital in the N ion was treated as afrozen core orbital. The results of the CI calculations
are independent of the choice of the initial orbitals.
To evaluate these adiabatic potential curves, wehave carried out the multichannel Landau-Zener calculations5) (MCLZ) for single-electron capture channels, using the adiabatic potential curves that include the capture into the N4+ (1s2 3s), N4+ (1s2 3p),
and N4+ (1s2 3d) states (not show in Fig. 1). Com-

∗1
∗2
∗3

96

Department of Physics, Sophia University
The University of Electro-Communications
Tokyo Institute of Technology

Fig. 1. Adiabatic potential curves calculated for double
electron-capture process.

parison of the present MCLZ calculations with experimental absolute cross sections measured by Beijers etal.,3) showed that our calculations, particulaly those of
the total and partial cross sections of the N4+ (1s2 3s)
state, are in fairly good agreement with the measurement. Thus, our adiabatic potential energy curves
are thought to be satisfactory for reproducing the experimental results. Figure 1 shows part of the abinitio adiabatic potential curves for double electron
capture channels, which we calculated in present work.
Solid lines in Fig. 1 show the capture channels we obtained from our experimental results. We found, fromthese potential curves, the avoided crossing points areabout 3.3, 4.8, and 5 atomic units(a.u.) for doubleelectron capture channels, which correspond to thecapture into the N3+ (1s2 2s4l, 1s2 2p3l), N3+ (1s2 2s3l),
and N3+ (1s2 2p2 ) states. From now on, we will compare our measured state-selective angular distributions
with the augular distributions calculated using theseadiabatic potential curves.
References
1) K. Ishii et al.: Phys. Rev. A 70, 042716 (2004).
2) D. Dijkkemp et al.: J. Phys. B 18, 4763(1985).
3) J. P. M. Beijers et al.: Phys. Rev. A 49, 363 (1994).
4) Y. Miyamoto et al.: RIKEN. Accel. Prog. Rep. 38, 92(2005).
5) A. Salop and R. E. Olson: Phys. Rev. A 13, 1312
(1979).

RIKEN Accel. Prog. Rep. 39 (2006)

Charge-state correlations in large-angle scattering
between Ne ion and Ar atom
M. Hoshino,∗1 T. Kambara, Y. Kanai, R. Schuch,∗2 and Y. Yamazaki
The interaction of slow highly charge ions (HCIs)
with clean metal surfaces has been studied intensively
over the past few years.1) The neutralization processesof HCIs from metal surfaces at large-angle scattering
have been investigated in detail. To study these processes from a diﬀerent viewpoint, we have been investigating the close collisions of slow HCIs with single
atoms as the elementary processes of ion-surface interactions. We previously reported the measurements ofcharge-state correlations between recoil and scatteredions for 5 keV Neq+ (q = 1, 2, and 3) on Ar.2) Recentry, we have measured the recoil-ion charge-state
distributions for q = 3, 5, and 7 in the energy range
of 5–63 keV. The mean charge states of both scatteredand recoil ions were also measured at 5 keV. Here, we
describe the results only for Ne7+ -Ar collisions.
The experiment was carried out at the Slow HighlyCharged Ion Beam Facility in RIKEN. The experimental setup has been reported elsewhere.2) A Ne-ion
beam from a 14.5 GHz Caprice-type ECR ion source
was collimated on a localized Ar gas from a needle.
Scattered Ne ions and recoil Ar ions were detected incoincidence at 27◦ and 70◦ with respect to the beam
direction using ion-detection telescopes. These angles
are expected from the kinematics of elastic scatteringof the Ne-Ar system. Each ion-detection telescope consists of a Time-of-Flight (TOF) drift tube to be set on
electrostatic potential, and a two-dimensional positionsensitive detector. For each coincidence event, the time
diﬀerence between the detections of the scattered andrecoil ions (∆TOF) and the positions of both ions wererecorded, from which we can obtain the charge-state
fraction of recoil ions (qAr ).
Figure 1 (a) shows the mean charge states of recoilions (qAr ) as a function of the impact energy in the collisions of Ne7+ with Ar. In Fig. 1 (a), the q Ar changed
drastically from approximately 5 to 7 as a step function around the impact energy of 35 keV, at which theclosest approach corresponds to the L-shell radius of
the Ar atom. The same behavior was observed for theenergy loss measurements in large-angle scattering between Ar+ and Ar at a higher impact energy region.3)
The fraction of each ﬁnal charge state (qAr ) from
3 to 8 is also shown in Fig. 1 (b). The fraction of
qAr = 4 and 5 decrease by a factor of three as theimpact energy increases. The fraction of qAr = 6 isalmost independent of impact energy, but it seems to∗1∗2

Fig. 1. Energy dependence of (a) mean charge states (•)
and (b) fraction of recoil ions in collisions of Ne7+ withAr. (◦): qAr = 3. (⊗): qAr = 4. (): qAr = 5. (+):
qAr = 6. (×): qAr = 7. (∗): qAr = 8.

have a peak at approximately 35 keV. The fractionsof qAr = 7 and 8 drastically increase at approximately
35 keV. A similar increase in qAr was observed in thecase of Ne3+ and Ne5+ impacts.
In the measurements of mean charge-state correlations between scattered and recoil ions at 5 keV, wehave found that the three-electron-capture and twoelectron-loss channel gave the maximum contribution
from ∆TOF shift for Ne7+ -Ar collisions. Therefore,
we assumed that these ﬁve electrons in the M -shell of
the Ar atom contribute in the reaction below 35 keV,
whereas at higher energies the internuclear distance isclose to the L-shell radius of Ar and the promotion of
L-shell electrons may contribute to the increase in qAr .
References
1) S. Hustedt et al.: Phys. Rev. A 50, 4993 (1995).
2) M. Hoshino et al.: Nucl. Instrum. Method Phys. Res. B
235, 347 (2005).
3) E. Everhart and Q. C. Kessel: Phys. Rev. Lett. 14, 247(1965).

Department of Physics, Sophia University
Atomic Physics, Stockholm University, Sweden

97

RIKEN Accel. Prog. Rep. 39 (2006)

Possible scheme for preparing microbeam of slow highly charged ionsusing tapered glass capillary
T. Ikeda, Y. Kanai, M. Hoshino,∗1 T. M. Kojima, T. Kambara, T. Nebiki,∗2 T. Narusawa,∗2 and Y. Yamazaki
We have started to develop a new techniquefor preparing micro/sub-microbeam of slow highly
charged ions (HCIs) using a tapered glass capillary at
RIKEN. We have succeeded in observing the guiding
eﬀect for the ﬁrst time.
Recently, microbeams of ions have been utilized invarious scientiﬁc ﬁelds. However, these microbeams
are mainly composed of protons or He ions with energies higher than 1 MeV. On the other hand, microbeams of slow HCIs have not yet been fully utilized.
The use of slow HCI microbeams could realize the pinpoint deposition of their large potential energy on thesurface of a sample, and oﬀer a unique opportunity ofsurface characterization by scanning microscopy. Sofar, microbeams are formed by collimation and focusing, using a double slit with a long interval and electromagnetic focusing lenses. This scheme requires a long
beam line and beam intensity is diminished. Our new
technique is based on the charge up inside an insulator
tube. It can provide the microbeams of HCIs with acertain intensity through its compact setup.
When positive ions enter the glass capillary, they
can make the inner wall positively charged up. The
electric ﬁeld prevents the following ions from coming inclose contact with the wall. The beam is thus guided
within the glass capillary and exits from the outlet,
which is smaller than the inlet, and the density of thebeam becomes higher (focusing eﬀect). This makes it
possible to realize a HCI microbeam without chargetransfer or energy loss.
The glass capillaries employed in this study, as
shown in Fig. 1, were 30–50 mm in length, 0.8 mm
in inlet diameter and 0.9–24 µm in outlet diameter.
They were made from borosilicate glass tubes 2 mm inouter diameter and 90 mm in length, these tubes melt
at 820◦ C (softening temperature). A glass tube washeated in the midlength at the softening temperature,and pulled at a constant velocity to form a tapered
glass capillary. The taper angle is determined by thetemperature and pulling velocity. An outlet with a diameter of ∼0.1 µm can be fabricated by this method.
As shown in Fig. 2, Ar8+ ion beam of 8 keV froma 14.5 GHz ECR ion source was collimated by a 4jaw slit so that the beam proﬁle was about 1.5 mm
square, and the intensity of the beam at the inlet of
the glass capillary was varied in the range of 0.1 – several pA. An Al plate with 4 mmφ holes was set infront of the glass capillary inlet so that any part ofthe initial beam cannot directly reach the downstream
elements. Moreover, a stainless ring with an outer diameter of 6 mmφ surrounding the inlet was also set.
A deﬂector just behind the glass capillary was used
for measuring the charge distribution of the transmitted beam. The transmitted ions were counted using
a position sensitive detector (PSD) with MCP’s anda wedge-and-strip type anode. The distance between
the outlet of the glass capillary and the PSD was about
100 mm. A metal tube parallel to the glass capillary
was installed to adjust the direction and position of
the ion beam.
To conﬁrm the guiding eﬀect, the glass capillary(φoutlet 24 µm) was tilted horizontally from −5◦ to+5◦ . Figure 3 shows the tilting angle dependence ofthe peak position for the beam intensity of ∼0.1 pA at
the inlet. The error was produced from the reading of
the tilting dial. The open circles show the calculated
positions. If the shape of the glass capillary is assumed
to be trapezoid, the geometrical limit of the tilting angle for a direct beam is about 0.49◦ . Therefore, it is
impossible to transmit ions in a tilting angle of morethan 0.49◦ without the guiding eﬀect.

Fig. 1. Glass capillary: The inset is a magnified image ofthe outlet taken by SEM.
∗1
∗2

98

Department of Physics, Sophia University
Kochi University of Technology

Fig. 2. Schematic view of setup: G. Cap. stands for glass
capillary.

Fig. 3. Horizontal position at PSD vs tilting angle: The
error was produced from the reading of the tilt dial.
The open circles show the calculated positions.

The probability of the charge transfer inside theglass capillary was also measured using the deﬂector
applied at 140 or 280 V. As a result, the contamination by Ar7+ in the transmitted ions was at most 10%
in the position distribution at the PSD for the tilting
angle of 0◦ or 3◦ . This implies that most ions did nottouch the inner wall. The beam spot at the PSD was
smaller than 0.7 mmφ (FWHM). The peak positions of
Ar8+ and Ar7+ ions of 8 keV were calibrated from theresults of the transmission with the metal tube.
Figure 4 shows the time dependence of the numberof transmitted ions for the beam intensity of about
1 pA without tilting. The transmission continued forFig. 4. Time dependence of number of transmitted ions: It
took several s to start the transmission and several tensof seconds to saturate the transmission rate.

more than 1200 s. (We did not measure the numberof transmitted ions longer than 1200 s) As shown in
the plot, it took several s to start the transmission andseveral tens of seconds to saturate the transmission
rate. These delays indicate that the inner wall was
charged up by the ion beam so that the beam wasproperly guided. In the cases of ∼0.1 pA inputs, thetransmission rate was not stable. The rise time of thetransmission rate could be determined from the beam
intensity and the discharge process of the glass surface.
A small peak (at around t = 25 s in this plot) appears
before the saturation. This phenomenon was observedin other results.

99

RIKEN Accel. Prog. Rep. 39 (2006)

Guiding of slow Ne ions transmitted through nanocapillaries inpolymer foils
Y. Kanai, M. Hoshino,∗1 T. Kambara, T. Ikeda, R. Hellhammer,∗2 N. Stolterfoht,∗2 and Y. Yamazaki
Recent observation1) has shown that slow highly
charged ions are guided when transmitted through capillaries of large aspect ratio (100 nm in diameter and10 µm in length) in a highly insulating polymer (PET:
polyethylene terephthalate) foil. The guiding eﬀect indicates that the inner walls of the insulator capillaries
are charged in a self-organizing process so that close
collisions with the surface are suppressed. In previous
experiments,1) only horizontal distributions of transmitted ions were measured. In order to obtain morecomprehensive information on the guiding eﬀect, westarted to measure the two-dimensional (2-D) imagesof transmitted ions through PET capillaries.
The experiments were performed at the Slow Highly
Charged Ion Facility at RIKEN.2) Beams of 3.5–7 keV
Ne7+ ions from a 14.5 GHz electron cyclotron resonance ion source were collimated to a diameter of 1 mm
and a divergence of 0.5◦ at a 10-µm-thick PET-foiltarget. Typical beam currents were 0.01–0.2 nA. The
PET foil had capillaries with a diameter of 200 nm,
whose density was 4 × 106 holes/cm2 . The front andexit sides of the PET foil were evaporated with Au,
producing a conducting ﬁlm of ∼ 20 nm thickness to
avoid charge up. 2-D images of transmitted ions were
measured using a position-sensitive detector with micro channel plates and a wedge-and-strip anode.
Figure 1 shows 2-D images of transmitted ions at different tilt angles of the PET foil relative to the beamwith 3.5 keV Ne7+ . By rotating the target tilt angle
from 0◦ to 4◦ , the peak positions of transmitted ions
moved to the capillary axis direction; that is, the deﬂection angle is nearly equal to the tilt angle. This

indicates that the ions were guided by the capillaries. As is seen in Fig. 1, the 2-D images of transmitted ions are isotropic and the angular widths of transmitted ions are about 1◦ . This is in good agreementwith the theoretical simulation,3) but diﬀerent fromthe previous measurements,1,4) where a high-capillarydensity (108 holes/cm2 ) PET foil was used and the angular width of transmitted ions was about 3◦ for 7 keV
Ne7+ .4) To discuss the relationship between the angular width of transmitted ions and the capillary density,
we need more experiments in which the capillary density is changed.
Figure 2 shows the integrated intensity of transmitted Ne7+ ions as a function of tilt angle for beam energies of 3.5, 4.9, and 7 keV. As the beam energy becomes lower, ions with larger tilt angles can be guided.
The maximum intensity is about 100 ions/pC, whichcorresponds to about 20% of the incident ions for eachcapillary being transmitted by the guiding eﬀect. Thiseﬃciency does not depend on the beam energy andcurrent under our experimental conditions; 3.5–7 keV
and 0.01–0.2 nA.

Fig. 2. Transmitted ion intensities for 3.5, 4.9, and 7 keV
Ne7+ ions. Intensities are normalized by incident beam
currents.

References

Fig. 1. 2-D images of ions transmitted through PET capillaries at tilt angle = 0◦ , 2◦ , and 4◦ . The beam energy
is 7 keV.
∗1
∗2

100

Department of Physics, Sophia University
Hahn-Meitner Institute, Germany1) N. Stolterfoht et al.: Phys. Rev. Lett. 88, 133201 (2002).
2) Y. Kanai et al.: Phys. Scr. T 92, 467 (2001).
3) K. Schiessl et al.: Nucl. Instrum. Methods Phys. Res. B
232, 228 (2005).
4) R. Hellhammer et al.: Nucl. Instrum. Methods Phys.
Res. B 232, 235 (2005).

RIKEN Accel. Prog. Rep. 39 (2006)

Measurement of momentum distributions of multiply charged raregas ions produced by an intense (∼1017 W/cm2 ) laser field
H. Shimada,∗ Y. Nakai, H. Oyama, K. Ando, A. Hatakeyama,∗ and Y. Yamazaki
With the advent of ultrafast laser technology, strong
electric ﬁeld of the order of one atomic unit or more(electric ﬁeld of 1 a.u. = 5.2 × 1011 V/m, corresponding
light intensity is 3.6 × 1016 W/cm2 ) has become experimentally accessible. The ionization of an atom withsuch a strong ﬁeld cannot be described in a perturbative manner and requires a diﬀerent approach. If theadiabaticity condition
ω
√
1
F 2IP
is fulﬁlled,1) where ω and F represent the frequency
and amplitude of the electric ﬁeld of light, and IP represents the ionization potential, the ionization is described as an escape of the electron from the atomic
potential deformed by the quasi-static electric ﬁeld.
Under this adiabaticity condition, a tunneling model,
known as the ADK model,2) has been successfully applied to describe the measured ion yield. At high ﬁeld
strength, where the assumption of the tunneling model
does not hold, a deviation from the ADK model has
been predicted.3) However, it has not been conﬁrmed
by ion yield measurements.
We report the deviation from the ADK model observed in ion momentum spectra. In this experiment, we have measured the momentum distributions of multiply charged Ar ions produced by an intense (∼(0.2–1) × 1017 W/cm2 ) laser ﬁeld. Ultrashort(∼200 fs, FWHM) pulses of linearly polarized nearinfrared (775 nm) light were used. The ion momentum
distributions along the light polarization direction were
measured by the time-of-ﬂight technique.
The measured momentum distributions of Ar ionsare plotted in Fig. 1. Each distribution has a peak atzero momentum, and their widths increase monotonically with the charge states (open squares in Fig. 2).
These results were compared with model calculations. A calculation based on the ADK model gave
narrower distributions (solid triangles in Fig. 2) thanthe experiment. This discrepancy can be attributed tothe tunneling approximation that is inappropriate near
the top of the potential barrier. Signiﬁcantly improved
results were obtained using more accurate ionization
rate near the top of the barrier3) (open triangles).
In summary, the momentum distributions of multiply charged Ar ions were measured. The distributions were compared using the calculation based on
the quasi-static treatment of the electric ﬁeld. The
well-known ADK model has proven to be insuﬃcient
to correctly describe the momentum distributions. The∗

Graduate School of Arts and Sciences, University of Tokyo

Fig. 1. Measured momentum distributions of Arq+ (q =2, 4, 6, 8) along light polarization direction. The vertical bars represent the magnitude of the experimental
uncertainties at the top of the peak.

Fig. 2. Experimental and calculated widths of momentum
distributions as a function of ionization potential. (✷:experimental results, : calculation employing ADK
model. : calculation employing improved rate at topof barrier.3) )use of the more accurate ionization rate near the topof the barrier improved the calculated results. Fromthese results, we conclude that the ion momentum
spectroscopy is more sensitive to the ionization model
than the yield measurement.
References
1) L. V. Keldysh: Zh. Eksp. Teor. Fiz. 47, 1945 (1964);
Sov. Phys. JETP 20, 1307 (1965).
2) M. V. Ammosov, N. B. Delone, and V. P. Krainov: Zh.
Eksp. Teor. Fiz. 91, 2008 (1986); Sov. Phys. JETP 64,
1191 (1986).
3) X. M. Tong and C. D. Lin: J. Phys. B 38, 2593 (2005).

101

RIKEN Accel. Prog. Rep. 39 (2006)

Space-charge shift in motional resonance of Ca+ by simultaneously
trapped molecular ions in a linear Paul trap
K. Okada,∗1 M. Wada, T. Takayanagi,∗1 T. Nakamura,∗2 I. Katayama,∗2 and S. Ohtani∗3
An ion trap connected to an rf ion guide is used toaccumulate an unstable ion beam in order to study the
Bohr-Weisskopf eﬀect of unstable alkaline earth ions.1)
In the initial stage of the experiment, buﬀer-gas coolingis applied as a simple and universal method of accumulating and cooling unstable ions which are injectedfrom the ion guide. In such an experiment, it is important to know how many ions are trapped and how
the ion cloud behaves in the ion trap.
In this short report, we present a new methodof estimating the number of buﬀer-gas-cooled invisible molecular ions through laser-induced ﬂuorescence(LIF) of simultaneously trapped visible Ca+ ions. The
systematic shift in the secular motion frequency of Ca+
was measured as a function of the production timeof molecular ions. The number of molecular ions wasevaluated from the frequency shift using a newly developed simple pesudopotential model.
For a systematic measurement of the space-charge
shift in the secular motion resonance of the Ca+
ions, molecular ions were prepared by the succesive
chemical reactions, Ca+∗ + O2 → CaO+ + O andCaO+ + H2 → CaOH+ + H, where these reactions are
triggered by the laser excitation of Ca+ to the 3d 2 DJ
state. The details of the experimental setup and theprocedure are described elsewhere.2,3) An important
point is that the ﬁnal products are CaOH+ ions andthe relative number of molecular ions can be controlled
simply by turning the lasers on and oﬀ.
As shown in Fig. 1, we systematically measured theshift of the secular motion of Ca+ ions as a function of
the Ca+∗ + O2 reaction time to determine the dependence on the number of molecular ions. Since the shift
in Fig. 1 is considered to be caused by the space-chargeof simultaneously trapped molecular ions, the numberof molecular ions can be estimated nondestructively.
To convert the space charge shift to the numberof molecular ions produced, a simple pseudopotential
model has been developed, the details of which will be
pubulished elsewhere.3) The secular frequency shiftedby the space-charge potential is given bykx,y− 2eaNion∼,(1)
ωobs =mwhere m and Nion are the mass of Ca+ ions and thetotal number of trapped molecular ions, respectively.
∗1
∗2
∗3

102

Department of Physics, Sophia University
Institute for Particle and Nuclear Studies, High Energy Accelerator Research Organization
Institute for Laser Science, University of Electro-Communications

Fig. 1. (a) Sequential measurement of secular motion resonance of trapped Ca+ ions as functions of Ca+∗ + O2
reaction time. (b) Evaluated number of molecular ionsobtained from the frequency shifts in (a).

kx,yis the radial trapping force constant for Ca+ .
The space charge factor a can be determined by theleast-squares ﬁt of the calculated space-charge potential of molecular ions near the central region when the
charge density distribution of the ions is assumed to
be a Gaussian function.3) Using Eq. (1), the numberof molecular ions Nion can be estimated. This equation is always applicable when the weak coupling condition is satisﬁed,4) i.e., |m1 − m2 |/m2  |c/k1 | andk1  |c|, where m1 and m2 represent the masses of
the two species of trapped ions. k1 and c represent a
trapping force constant for m1 and the repelling force
constant between two species of ions, respectively.
The space-charge potential of the trapped molecularions can be numerically calculated using experimental
values of ωx,y,z and Tion . As shown in Fig. 1 (b), theshift of the Ca+ spectra is converted to the numberof trapped molecular ions. This new method can beapplied for various partner ions in principle, as long as
the weak coupling condition is satisﬁed between probe
atomic ions and invisible ions.

References
1) M. Wada et al.: RIKEN Rev., No.31, 56 (2000).
2) K. Okada et al.: J. Phys. B 36, 33 (2003).
3) K. Okada et al.: Jpn. J. Appl. Phys. 45, 951 (2006).
4) K. Jungmann et al.: Phys. Rev. A 36, 3451 (1987).

RIKEN Accel. Prog. Rep. 39 (2006)

Excitation spectrum of Al atoms in He II
T. Itou,∗1 T. Furukawa,∗2 Y. Matsuo, A. Hatakeyama,∗3 T. Kobayashi, Y. Ota,∗1
H. Odashima,∗1 and T. Shimoda∗2
Superﬂuid helium (He II) is expected to be a suitablemedium for instantly trapping atoms and ions of highkinetic energy. We are planning to measure the nuclear
moments of atoms with unstable nuclei trapped in He
II by the laser spectroscopic method.1) Atoms in He
II show a large shift and broadening of their atomic
excitation spectra, whereas the shift and broadening
are relatively small in the emission stage, because implanted atoms reside in bubble-like cavities (He bubble).2) Taking advantage of this unique property, theoptical pumping method, which has been achieved only
for alkaline and alkali-like atoms to date, may be applicable to various atoms. The aluminium atom is important in nuclear physics because of the proton halo
structure suggested from a recent study of proton-richnuclei of Al. To achieve an eﬃcient optical pumping,
the wavelength of the laser should be at the peak position of the excitation spectrum in He II where absorption eﬃciency is maximum. However, a previously
reported peak wavelength had large experimental uncertainties because the laser power correction was not
suﬃcient.3) In this paper, we report laser-induced ﬂuorescence (LIF) spectra of Al atoms obtained by removing the eﬀect of excitation laser power dependence
on its wavelength.
The experimental setup is shown in Fig. 1. The
apparatus consisted of a cryostat chamber (Oxford)
with quartz windows, a detection system, and threelasers. The bottom part of the cryostat contained liquid He. An open-top quartz cell (70 × 70 × 70 mm3 )was placed above the liquid surface and was ﬁlled withHe II by transferring liquid He utilizing the fountaineﬀect of He II. An Al sample held about 1 cm above

the quartz cell was ablated with an output of the third
harmonic generation of a Nd:YAG laser through oneof the windows. Then, Al clusters produced by laser
ablation were dissociated to disperse Al atoms in He
II by the second harmonic output of another Nd:YAG
laser. The implanted Al atoms whose densities areabout 108 –1010 cm−3 in He II were excited from theground 2 P1/2 state to the 2 S1/2 excited state with apulsed dye laser. Operating a variable ND-ﬁlter manually, the dye laser power was maintained weak andconstant (approximately 0.1 µJ/pulse). Thus, the implanted clusters were not dissociated any further, and
LIF intensity is free from the eﬀect of laser power.
Emitted photons were collected with a photomultipliertube (PMT) through a monochromator ﬁxed at an Alemission wavelength of 397 nm, and the obtained signal
was sent to a PC.
Figure 2 shows an excitation spectrum of Al in He
II. LIF intensity observed at 397 nm is plotted against
excitation laser wavelengths from 345 nm to 370 nm.
The peak position and width of the excitation spectrum are 354 nm and about 11 nm, respectively. The
peak wavelength is found to be 4 nm shorter than that
previously reported in Ref. 3. We are planning to apply the optical pumping method to Al atoms at thepeak wavelength obtained in this experiment, and tomeasure the nuclear moments of proton-rich nuclei ofAl.

Fig. 2. Excitation spectrum of Al atom in He II. The large
intensity variation in the spectrum is mainly caused by
the fluctuation of the number of atoms implanted bylaser ablation.

References
Fig. 1. Experimental setup.
∗1
∗2
∗3

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

1) T. Furukawa et al.: RIKEN Accel. Prog. Rep. 38, 99(2005).
2) B. Tabbert, H. Günther, and G. zu Putlitz: J. Low
Temp. Phys. 109, 653 (1997).
3) Q. Hui, J. L. Persson, J. H. M. Beijersbergen, and M.
Takami: Z. Phys. B 98, 353 (1995).

103

RIKEN Accel. Prog. Rep. 39 (2006)

Hyperfine-structure spectroscopy of stable 133 Cs atoms in He II
T. Furukawa,∗1 Y. Matsuo, A. Hatakeyama,∗2 T. Ito,∗3 Y. Ota,∗3 Y. Fukuyama,∗4
T. Kobayashi, and T. Shimoda∗1
We have been studying the hyperﬁne structures of
impurity atoms in superﬂuid helium (He II) with theaim of establishing a versatile method for determining
the nuclear moments of unstable nuclei.1) The atoms
implanted in He II have a broadened absorption line
spectrum (≥ 10 nm) and a long spin relaxation time
despite the broadened line.2) The broadened line spectrum is very promising for pumping various atomic
species not only alkali atoms but also nonalkalis suchas Al and Mg, because the broadened spectrum covers
all of complicatedly split lines in many cases. Furthermore, the long spin relaxation time of Cs atoms in He
II (≥ 2 s) has been conﬁrmed experimentally.3) Those
phenomena suggest that He II is a suitable medium
for measuring the hyperﬁne structure of an impurity
atom, and for determining the nuclear moments fromthe hyperﬁne structure. We now report the measurement of a previously reported hyperﬁne transition in
the ground state of Cs atoms (|F  : |4 → |3) immersed in He II by the double resonance method4) tocheck our experimental system.
The double resonance method is based on the factthat the laser-induced ﬂuorescence (LIF) intensity I
observed with the irradiation of circularly polarized“pumping” light, tuned to the wavelength of the D1
excitation line of Cs atoms in He II, is related to thepolarization of Cs atoms as
I ∝ NCs × (1 − Pl × Pz ),(1)

where NCs is the number of Cs atoms, Pl is the polarization of pumping laser light, and Pz is the electronic spin polarization of the atoms.5,6) The detailsof the method are as follows. At the beginning of
the measurement, Cs atoms are laser-sputtered andintroduced into the optical detection region in He II
where the pumping laser light and the microwave for
hyperﬁne transition are both irradiated continuously.3)
Next, the introduced Cs atoms are optically pumped
and polarized by the irradiation of circularly polarizedpumping laser light, then LIF intensity is decreased
during a period shorter than 1 ms. Note that, if thehyperﬁne transition occurs on resonance, the polarized atoms are depolarized and LIF intensity increases
compared with the oﬀ resonant case. Before and after
the optical pumping, the linearly polarized pumping
laser is irradiated to check the number of Cs atoms
because LIF intensity with the linearly polarized laser
∗1
∗2
∗3
∗4

104

Department of Physics, Osaka University
Department of Basic Science, University of Tokyo
Institute of Physics, Meiji University
Spring-8

light is related only to the number of Cs atoms deduced from Eq. (1). By sweeping the microwave frequency, we can search for hyperﬁne transition to determine hyperﬁne splitting energy. It should be notedthat each of the hyperﬁne levels splits into Zeeman
sublevels owing to an external magnetic ﬁeld. Because of this eﬀect, the diﬀerent transition frequencies
of |F, mF  : |4, +4 → |3, +3 and |4, −4 → |3, −3
are measured with the σ + and σ − pumping lasers, respectively. Nonperturbed hyperﬁne splitting energy is
obtained as an average of two resonant frequencies.7)
Figure 1 shows LIF intensity as a function of microwave frequency. With simple Lorentzian ﬁttings,
the resonant frequencies are determined preliminarily
to be 9.25773(1) GHz in σ + pumping and 9.24352(1)GHz in σ − pumping. Thus, the hyperﬁne coupling
constant A of 133 Cs atoms immersed in He II is preliminarily determined as 2.312655(5) GHz, which is consistent with previous data4) and the error is 20 times
smaller than the previous data. This value is slightly
larger (0.6%) than that in vacuum, probably owing
to the eﬀects of He II pressure. The obtained narrow
resonance line width of approximately 150 kHz and theresonant frequency close to that in vacuum (0.6% difference) are suitable for measuring nuclear moments
within an uncertainty of 1% required for investigating
the nuclear structure. Note that it is conceivable that
there is no diﬀerence in the size of isotope atoms compressed in He II. To conﬁrm this, we will next measure
the hyperﬁne structures of 85,87 Rb isotopes.

Fig. 1. Measured hyperfine transitions with σ + (left) andσ − (right) pumping.

References
1) T. Furukawa et al.: Ann. Rep. (Osaka University Laboratory of Nuclear Studies) 27 (2002).
2) B. Tabbert, H. Günther, and G. zu Putlitz: J. Low
Temp. Phys. 109, 653 (1997).
3) T. Furukawa et al.: Phys. Rev. Lett. 96, 095301 (2006).
4) Y. Takahashi et al.: Z. Phys. 98, 391 (1995).
5) M. Arndt et al.: Phys. Rev. Lett. 74, 1359 (1995).
6) S. Lang et al.: Phys. Rev. A 60, 3867 (1999).
7) S. Lang et al.: Europhys. Lett. 30 (4), 233 (1995).

RIKEN Accel. Prog. Rep. 39 (2006)

Research for acceleration of Al by Direct Plasma Injection Scheme
K. Sakakibara,∗1 M. Okamura, S. Kondrashev, H. Kashiwagi, and T. Kanesue∗2
Linac is used in various ﬁelds, for example as a synchrotron injector, for the implantation and improvement of which is a very signiﬁcant theme. However,in a low energy region between an ion source and an
accelerator, space charge eﬀect is very strong and it
causes beam losses.
To resolve this, a new acceleration scheme for highcharge-state and high-intensity beam was invented.
This scheme is called “Direct Plasma Injection Scheme(DPIS).” In DPIS, a laser ion source is used and connected to Radio Frequency Quadrupole (RFQ) linac
directly without a beam transport line. It can prevent serious beam losses by space charge eﬀect in Low
Energy Beam Transport and possibly accelerate highcharge and high-intensity beam. We succeeded in accelerating C4+ (60 mA) using a CO2 laser,1) and C6+ions using a YAG laser.2)
As a new step, we will accelerate a heavier element
Al using this scheme. Before the acceleration, we measured Al-laser-produced plasma properties. We also
simulated the acceleration of Al using PTEQ-HI.
Figure 1 shows the experimental equipments for
the Al plasma measurement. The glass laser has awavelength of 1064 nm and its maximum energy is
4.39 J/cm2 per shot. The laser was a courtesy of Center for Nuclear Study, Tokyo University. The spot sizeand pulse length are 1 cm and 40 ns, respectively. In
the target chamber, the laser was focused using a convex lens (focal length: 100 mm) and was emitted tothe target suspended by a supporting rod. We placeda Faraday cup (aperture 10 mm) and measured the total current of the plasma. An electrostatic analyzer

was used to obtain charge distribution and signals weredetected by a secondary electron multiplier (SEM).
We obtained Al plasma current and charge state
distribution and were able to determine the numberof ions produced in each charge state. We also did
the simulation of Al ion acceleration. The simulation
study was done using a multispecies beam tracking
cord, PTEQ-HI, in the RFQ. Al9+ was selected as
the target ion of acceleration. The beam current, including multiple charge states which will be injectedto the RFQ can be estimated from the ion property.
The acceleration performance of the Al9+ beam wasinvestigated. In the simulation, we assumed that Al
plasma included only Al6+ ∼Al9+ . The total percentage of the simulated currents corresponded to 83.4%
of all the currents of the measured plasma. The initial
parameters are listed in Table 1.
The operating frequency and the extraction energy
were 100 MHz and 100 keV/amu, respectively. The RF
voltage was set to the design value of the RFQ for accelerating C4+ beam. The numbers of particles in thesimulation are 3000 for Al9+ and 1500 for other charge
states. We counted the particles which had more than
40% energy shift with respect to the synchronous particle as lost particles.
The result of the simulation shows that the expectedcurrent of Al9+ is about 42 mA (61.4% survive). Someportions of the Al8+ , Al7+ and Al6+ ions will be also
accelerated. The simulated currents at the end of
the RFQ were 54 mA (41.3%), 31.9 mA (24.1%) and4.7 mA (8.8%).
The contents of the Al plasma induced by the glass
laser were measured and we simulated the acceleration performance of the Al beam using our new RFQ.
According to the simulation, 42 mA of Al9+ will be
accelerated.
We will try heavier species up to gold this year toestablish the DPIS as an intense heavy-ion production
method.
Table 1. Initial parameter for PTEQ-HI.
Main particle
Injection beam current
Injection energy

Al+9
68 mA
540 keV (total)

References
Fig. 1. Experimental setup.
∗1∗21) M. Okamura et al.: Laser Part. Beams 20, 451 (2002).
2) H. Kashiwagi et al.: Rev. Sci. Instrum. 75, 1569 (2004).

Tokyo Institute of Technology
Kyushu University

105

RIKEN Accel. Prog. Rep. 39 (2006)

Shot-to-shot stability of ion generation by solid-state laser
T. Kanesue,∗1 S. Kondrashev,∗2 M. Okamura, and K. Sakakibara∗3
To obtain higher-intensity highly charged heavy-ion
beams, we are developing a new combination of theLaser Ion Source (LIS) and RFQ linac, the Direct
Plasma Injection Scheme.1) We plan to accelerate ion
species heavier than carbon this year. Previously, theion yield from C, Al, Ti, Fe, Ge, Nb and Ta targets wasmeasured. The main results obtained are presented inRef. 2.
In this paper, we describe the shot-to-shot stabilityof ion yield generated by the solid-state Nd-glass laser:
3 J/30 ns, B. M. Industries model 511 DNS13 (courtesyof the Center for Nuclear Study, University of Tokyo).
A movable target was placed inside a vacuum chamber with a residual gas pressure of about 10−6 Torr.
The use of a 3D manipulator enabled us to move thetarget with a minimal step of about 10 µm. A laser
beam was focused on the target surface by a convex
lens with a 100 mm focal length at an incident angleof about 30◦ from the target normal axis. A detailed
description of the experimental setup is presented inRef. 3.
The following procedure was applied to determine
the best target position for the generation of the highest charge states for all elements: the target was moved
along the direction normal to the surface in 0.25 mmsteps and total ion current was measured using a Faraday cup (FC) for each target position. The target position with the maximal measured current and fastest
arrival of ions to the FC was chosen for highly charged
ion generation. The Al case is shown in Fig. 1. In thiscase, −2 mm was chosen as the best target position.
All the other elements tested have shown similar behaviors. After deﬁning the target position as describedabove, the charge state and energy distributions of ionswere measured. It was conﬁrmed that the target position determined as described above provides the highest yield of highly charged ions.
To check the shot-to-shot stability of ion yield generation, ion current was measured for 5 laser shots at
diﬀerent spots with enough steps to use a fresh target
surface and 5 shots at the same spot for 6 elements:
Al, Fe, Ti, Ge, Nb, Ta.
The shot-to-shot stabilities in the case of diﬀerent
spots for Al, Fe, Ti, Ge, Nb and Ta targets were ±3%,±5%, ±19%, ±19%, ±20% and ±16%, respectively,from the average FC peak current.
Typical FC signals are shown in Fig. 2 for the Al
target in the case of the same spot laser shot. All 6elements have shown similar tendencies: the ﬁrst shot
always produced the highest current and then current
gradually decreased. Drastic changes were observedin the cases of Al, Fe, Ti and Ge targets: currents
were reduced to 23%, 13%, 28% and 18%, respectively,of the ﬁrst-shot current even in the second shot andremained small to the same extent in all subsequentshots. In the case of Nb and Ta targets, the changed
second-shot currents were 77% and 97% of the ﬁrstshot current. It also gradually decreased. The smallest
currents were 33% of the ﬁrst shot in the fourth shotin the case of the Nb target, and 67% in the ﬁfth shotin the case of the Ta target.
Al and Fe had stabilities below 5% on the fresh surface. Ge, Nb and Ta signals were more sensitive; theyeasily change by about ±20% even on the fresh surface.
It is important that the ﬁrst laser shot onto the fresh
target surface always provides the highest ion yield at
the same target spot. For this reason, the target should
be moved between laser shots to hit a fresh target surface. Such an approach will provide the highest andmost stable ion yield.

Fig. 1. The curves are for ion group arrival time, peak time,and FC peak current.

Fig. 2. FC signals (5 shots at the same spot).

∗1
∗2
∗3

106

Department of Energy Science and Engineering, Kyushu
University
Institute of Theoretical and Experimental Physics, Russia
Department of Energy Sciences, Tokyo Institute of Technology

References
1) T. Takeuchi et al.: Rev. Sci. Instrum. 73, 764 (2002).
2) S. Kondrashev et al.: RIKEN Accel. Prog. Rep. 39, 268(2006).
3) K. Sakakibara et al.: RIKEN Accel. Prog. Rep. 39, 105(2006).

RIKEN Accel. Prog. Rep. 39 (2006)µSR study of magnetic property of α-(BETS)2 I3
S. Ohira, R. Kato, N. Tajima, K. Hiraki,∗ and T. Takahashi∗
Recently, many interesting physical properties ofvarious organic conductors have been reported. The
relationship between their magnetism and electric
conductivity is now drawing much attention. α(BETS)2 I3 is an organic conductor having a quasi2D layered structure. This salt exhibits a metalinsulator (MI) transition at TMI = 50 K.1,2) Below TMI ,77
Se NMR3) and magnetic susceptibility measurements
showed a nonmagnetic state, while the observed magnetotransport suggests the existence of strong magnetic interactions at low temperatures with a large negative magnetoresistance under an external ﬁeld applied
perpendicular to the conducting layer.4) Therefore, themagnetic state of this salt has not been clariﬁed yet.
We investigated the magnetic state of this material below TMI by the µSR method. 60 mg of polycrystalline
sample was packed in a silver foil and ﬁxed on the sample holder of the cryostat. The experiment was carriedout at the RIKEN-RAL Muon Facility in the Rutherford Appleton Laboratory.
In the ZF-µSR time spectra, the muon spin relaxation due to nuclear dipole ﬁelds was observed down to
1.8 K. The spectra are ﬁtted with the relaxation function, A(t) = A exp[−(λt)β ], where λ is the muon spin
relaxation rate describing dynamical ﬂuctuations andβ is the exponent. The temperature dependences of λand β are shown in Fig. 1. We note that λ starts toincrease at TMI = 50 K with decreasing temperature.
This behavior is signiﬁcantly diﬀerent from magnetictransition, where λ should show a cusp. A similar temperature dependence is observed in some spin-singlet
materials.5,6) It has been suggested that thermally activated excitations across the magnetic gap are responsible for the relaxation. Therefore, our result indicatesthe nonmagnetic state below TMI .
Another noteworthy change is observed in the temperature dependence of β at about 20 K. β shows aconstant value ∼1.2 above 20 K. At lower temperatures, however, it approaches 1, namely, the time spectra show an exponential relaxation. This suggests that
another dynamical contribution to the muon spin relaxation appears below 20 K, as well as in another spinsinglet organic material.6) This change is more clearlyobserved in the longitudinal-ﬁeld (LF) µSR measurement. The amplitude of the dynamical component increases below 20 K, as shown in Fig. 2. The relaxation mechanism below ∼20 K is expected to be different from that in the higher-temperature region. We
consider that dilute defect spins, existing naturally or
resulting from the implantation of the muon, provide
an additional dynamical component. The existence ofmagnetic interactions as suggested by the magnetotransport measurement is also conceivable.

Fig. 2. Temperature dependence of amplitudes of dynamical and static components in the LF-µSR measurement
at 30 G.

References

Fig. 1. Temperature dependences of (a) relaxation rate λand (b) exponent β.
∗

Department of Physics, Gakushuin University

1) M. Inokuchi et al.: Bull. Chem. Soc. Jpn. 68, 547(1995).
2) N. Tajima et al.: J. Phys. Soc. Jpn. 69, 543 (2000).
3) K. Hiraki et al.: Meeting Abstracts of Phys. Soc. Jpn.
59, Issue 1, Part 4, 829 (2004).
4) N. Tajima et al.: Synth. Met. 86, 1981 (1997).
5) S. J. Blundell et al.: J. Phys., Condens. Matter 9, L119
(1997).
6) S. Ohira et al.: Physica B, in press.

107

RIKEN Accel. Prog. Rep. 39 (2006)

Preparation of Th target for heavy element studies with GARIS
H. Haba, D. Kaji, T. Takabe,∗1 and H. Kikunaga∗2
We plan to study the chemical properties of superheavy elements (SHEs) with atomic number Z ≥104 by developing the gas-jet transport system coupled to the gas-filled recoil separator GARIS at the
RIKEN Linear Accelerator Facility (RILAC).1) SHE
nuclides for the chemical experiments have been produced by heavy-ion induced fusion reactions on actinide targets such as 238 U, 248 Cm, and 249 Bk. Because of the extremely low production yields of SHEs,
stable targets are desired for high-intensity heavyion bombardments for beam times of long duration.
Thus, the actinide targets in oxide form have been
prepared by electrodeposition from organic solutions(molecular-plating method). Recently, multitarget devices mounted on a rotating wheel have been developed to prevent the excessive heating of a stationary
target.2,3) However, it is still hard to prepare a large
and uniform target layer by electrodeposition.
Using the GARIS and gas-jet transport system, we
will first intend to study the chemical properties of
elements 106 (Sg) and 108 (Hs). For this purpose,experiments searching for 265 Sg and 269 Hs using the232
Th(40 Ar, α3n)265 Sg and 232 Th(40 Ar,3n)269 Hs reactions are in progress,4) because high-intensity 40 Ar
beams up to 10 particle µA (pµA) are expected at
RILAC. Here, we report a technical development for
preparing a large and uniform ThO2 target by electrodeposition for irradiations using a rotating target
system of GARIS.
Figure 1 shows a schematic view of the newly developed cell for electrodeposition. A Ti backing foil of
2.8 µm thickness placed on the water-cooled Ti block
was used as the cathode, whereas a Pt plate of 0.1 mm
thickness on another Ti block was used as the anode.
A Teflon spacer perforated in the shape of a banana
and of 10 mm thickness was sandwiched by the electrodes sealed using silicon rubbers perforated in thesame banana shape and of 1 mm thickness. The active
target area of 7.85 cm2 is more than two times larger

than those used in the previous Dubna and GSI experiments.2,3)
Five microliters of 0.01 M HNO3 containing 2.7 mgof Th was mixed with 10 mL of 2-propanol, and the
mixture was filled into the cell as shown in Fig. 1. Electrodeposition was carried out by applying a voltage of
600 V with current densities from 2 to 6 mA cm−2 for
20 min. During the electrodeposition, the Ti blocks
were water-cooled at 10◦ C. After the electrodeposition, the target was heated in an electric furnace at
350◦ C for 20 min to obtain ThO2 . The target thickness of 320 ± 30 µg cm−2 averaged for the 16 targets
was determined by α spectrometry on 232 Th. The deposition yield was not less than 90%. The uniformityof the target was investigated using the imaging plateFujifilm BAS-MS 2325. The target densities are shownin Fig. 2 for each 1.0 mm × 1.0 mm pixel. Deviationsin the target density are less than 8% except for the
2 mm outer edge of the target.
The 16 Th targets were arranged on the rotating
wheel of 30 cm diameter and were irradiated by the222.5 MeV 40 Ar beam (total dose of 1.3×1018 ions withbeam currents up to 2 pµA).4) The target wheel was
rotated during the irradiation at 3000 rpm and cooledwith He gas filled in GARIS at a pressure of 88 Pa. No
damages or losses of the target material were observed
after the irradiation on the basis of α spectrometry.
In the near future, we will develop rotating U3 O8 targets to study possible production of 283 112 for chemical
studies of element 112 using the 238 U(48 Ca,3n)283 112
reaction.

Fig. 2. Density distribution of Th target for each 1.0 mm
× 1.0 mm pixel.

References

Fig. 1. Schematic view of cell for electrodeposition.
∗1∗2

Graduate School of Science, Osaka University
Faculty of Science, Kanazawa University

1) H. Haba et al.: RIKEN Accel. Prog. Rep. 38, 103(2005).
2) Yu. V. Lobanov et al.: Nucl. Instrum. Methods Phys.
Res. A 397, 26 (1997).
3) K. Eberhardt et al.: Nucl. Instrum. Methods Phys. Res.
A 521, 208 (2004).
4) D. Kaji et al.: RIKEN Accel. Prog. Rep. 39, 110 (2006).

109

RIKEN Accel. Prog. Rep. 39 (2006)

Search for superheavy-element nuclides for chemical studies
using 232 Th+40 Ar reaction
D. Kaji, H. Haba, K. Morimoto, T. Akiyama,∗1 K. Morita, N. Sato,∗2 T. Takabe,∗3 and A. Shinohara∗3Long-lived superheavy-element (SHE) nuclides forchemical studies were searched for in the 232 Th+40 Ar
reaction using the gas-ﬁlled recoil separator (GARIS)
at RIKEN. SHE nuclides near deformed shells of
Z=108 and N =162 are of special interest. These
nuclides have been reported as reaction products
from 238 U- and 248 Cm-based reactions, such as
238
U(34 S,5n)267 Hs,1) 248 Cm(22 Ne,xn)266, 265 Sg [x=4,2)5] and 248 Cm(26 Mg,xn)270, 269 Hs [x=4, 5],3) or decay
products of 277 112 produced by the 208 Pb(70 Zn,n) reaction.4) In this work, the 232 Th+40 Ar reaction is considered to be a candidate reaction that produces SHE
nuclides. In this reaction, it is interesting from the reaction mechanism viewpoint whether the (HI,αxn) enhancement of the production cross section as describedin Ref. 5 is observed or not.
The 232 ThO2 target was irradiated with an
40
Ar11+ beam at two beam energies of 4.97 and5.18 MeV/nucleon corresponding to excitation energies of 39.1 and 46.3 MeV, respectively.
Excitation energy is deduced using the mass formula of
KUTY.6) The former beam energy was set to searchfor 232 Th(40 Ar,4n)268 Hs or 232 Th(40 Ar,αxn)266, 265 Sg[x=2, 3], and the latter was for 232 Th(40 Ar,5n)267 Hs
or 232 Th(40 Ar,α3n)265 Sg. The ambiguity of the absolute beam energy was ±0.3 MeV. The typical beam
intensity on the target was 1.0 particle µA. The target
was prepared by the electrodeposition of 232 Th onto
a titanium backing foil of 2.8 µm thickness. Detailsof the target preparation are given in Ref. 7. Sixteen
targets were mounted on a rotating wheel of 30 cm diameter. The wheel was rotated at 3000 rpm during theirradiation. The average thickness of each 232 Th layer
was 320±30 µg/cm2 . Evaporation residues (ERs) recoiling out of the target were separated in-ﬂight fromthe other charged particles, such as beam particles andtarget recoils by the GARIS. After passing two timeof-ﬂight (TOF) pickups, the ERs were implanted into a
position-sensitive silicon detector, where their decays
were measured. The separator was ﬁlled with a helium gas at 86 Pa. The magnetic rigidity Bρ in themeasurement of the ERs was set to 2.04 Tm, which isestimated using our empirical formula.8)
The target was irradiated with 40 Ar at doses of
3.0×1017 and 1.16×1018 at beam energies of 4.97 and5.18 MeV/nucleon, respectively. No candidate α-decay
and spontaneous ﬁssion (SF) decay due to the pro∗1
∗2
∗3

110

Department of Physics, Saitama University
Department of Physics, Tohoku University
Department of Chemistry, Graduate School of Science, Osaka University

duction of 267, 268 Hs and 265, 266 Sg were observed.
The two-fold and three-fold correlation analyses of
ER-α1 /SF and ER-α1 -α2 /SF were performed under
the following conditions: ER-kinetic energy gate of 5
≤ EER ≤25 MeV, α-energy gate of 7 ≤ Eα ≤12 MeV,
SF-energy gate of ESF ≥ 50 MeV, position gate of∆P ≤2.0 mm and time gate of ∆τ ≤1000 sec. The 1σ upper limit (conﬁdence level=68%) of the cross section in each reaction is estimated to be 31 pb for 268 Hs,
185 pb for 266, 265 Sg at 4.97 MeV/nucleon, and 8 pb for267
Hs and 48 pb for 265 Sg at 5.18 MeV/nucleon, where
the transmission eﬃciencies of the GARIS for xn and
αxn emissions are estimated to be 24% and 4%, respectively. Transmission eﬃciency is deduced by taking the angular distribution of residual nuclei producedin each reaction, the multiple scattering of recoil ionswith helium atoms and the geometrical transmission of
TOF detectors into account. The transmission in αxnemission is smaller than that in xn emission, because
the angular distribution is not forward-peaked but isside-peaked due to the large recoil eﬀect induced by
α-emission.
We will continue to search for SHE nuclides forchemical studies using the 232 Th+40 Ar reaction. In
particular, the production of 269 Hs produced via
232
Th(40 Ar,3n) is interesting.
References
1) Yu. A. Lazarev et al.: Phys. Rev. Lett. 75, 1903 (1995).
2) Yu. A. Lazarev et al.: Phys. Rev. Lett. 73, 624 (1994);
M. Schädel et al.: Nature 388, 55 (1997); A. Türler etal.: Phys. Rev. C 57, 1648 (1998).
3) Ch. E. Düllmann et al.: Nature 418, 859 (2002); A.
Türler et al.: Eur. Phys. J. A 17, 505 (2003).
4) S. Hofmann et al.: Z. Phys. A 354, 229 (1996); S. Hofmann et al.: Eur. Phys. J. A 14, 147 (2002).
5) T. Nomura et al.: Proc. Int. Symp. on Heavy Ion
Physics and Its Application, Lanzhaou, China, 1990-10(World Scientific, Singapore, 1991), p. 349; T. Nomura
et al.: Proc. Int. Symp. on Structure and Reactions of
Unstable Nuclei, Niigata, 1991-6 (World Scientific, Singapore, 1992), p. 310.
6) H. Koura et al.: Nucl. Phys. A 674, 47 (2000).
7) H. Haba et al.: RIKEN Accel. Prog. Rep. 39, 109(2006).
8) D. Kaji et al.: RIKEN Accel. Prog. Rep. 36, 88(2003); D. Kaji: Doctoral Dissertation, Niigata University, (2003).

RIKEN Accel. Prog. Rep. 39 (2006)

Development of online solvent extraction system using microchip
D. Saika,∗ Y. Kitamoto,∗ K. Matsuo,∗ Y. Tashiro,∗ T. Takabe,∗ T. Yoshimura,∗ W. Sato,∗ N. Takahashi,∗
H. Haba, S. Enomoto, and A. Shinohara∗
We have developed a rapid reaction and measuringsystem for studying the chemical properties of heavy
and trans-actinide elements. Their half-lives are soshort that it is diﬃcult to study their chemical behaviors by a conventional method. To overcome thediﬃculty, we used a microchip for solvent extraction.
A microchip is a reactor vessel made of glass or plastics
with etched channels of dozens to hundreds micrometers in width. Because molecules diﬀuse more rapidly
in such a small vessel than in an ordinary vessel of a
cm size, a diﬀusion-limited reaction can achieve equilibrium very rapidly in a microchip.1) Here, we show
the results of solvent extraction using a microchip forlanthanide elements as a simulation of actinides.
At ﬁrst, we determined the time for the extractionof lanthanide radiotracers to reach equilibrium using
TTA (thenoyl-triﬂuoroacetone) as a ligand. We used
0.1 M acetate buﬀer solution containing 153 Gd, 139 Ce,
88
Y, and 170 Tm as aqueous phase, and 0.044 M TTAtoluene solution as organic phase. Each solution was
infused into the microchip using syringe pumps, andsolvent reactions occurred during their contact at theliquid interface. We can vary their contact time bycontrolling the ﬂow rate of syringe pumps and determined the time for the extraction of lanthanide
to reach equilibrium. Their activities were measuredby γ-ray spectrometry using a Ge detector and theextraction ratio D was derived using the equation
D = Vaq · Aorg /Vorg · Aaq , where V is the volume and
A is the radioactivity.
We applied the microchip method to online chemical
experiments performed at RIKEN Ring Cyclotron E3bcourse. The nat Ta targets (2 µm × 30 sheets) were irradiated with 135 MeV/nucleon 14 N ions, and many lanthanide radionuclides were produced by nat Ta (14 N, X)
reaction. These radionuclides were transported to the
hot laboratory within a few seconds by the gas-jet
method,2) and dissolved by an acetate buﬀer solution.
This solution was infused to the microchip simultaneously with the TTA-toluene solution. Then, the radionuclides were rapidly extracted from the aqueous
phase to the organic phase. It took less than 2 min
to extract the species from the production of radionuclides to the measurement in this experiment.
To compare with the microchip method, we performed batch extraction. An aqueous solution containing radionuclides was mixed with TTA-toluene solution, shaken for 3 min, and separated by centrifugation.
∗

The extraction ratios D of lanthanide elements areshown in Fig. 1. The D values of the microchip extraction method nearly correspond to those obtainedby the batch extraction method. This result showsthat heavier lanthanide elements are extracted more
into the organic phase and the microchip method isapplicable to online chemical experiments. The application is also expected for actinide elements because
they have similar chemical properties to lanthanide elements.
We have conﬁrmed that the equilibrium for the extraction of lanthanide is achieved within one second as
shown in Fig. 2. These results show that the use ofa microchip enables the extraction of heavy elements
whose half-lives are in the order of seconds.

Fig. 1. Extraction ratios D of microchip and batch experiments.

Fig. 2. Extraction rate of lanthanides using microchip.

References
1) H. Hisamoto et al.: Chem. Commun. 24, 2662 (2001).
2) E. Stender, N. Trautmann, and G. Herrman: Radiochem. Radioanal. Lett. 42, 291 (1980).

Graduate School of Science, Osaka University

111

RIKEN Accel. Prog. Rep. 39 (2006)

Development of capillary electrophoresis apparatus
for heavy actinide chemistry
Y. Kitamoto,∗1 D. Saika,∗1 K. Matsuo,∗1 Y. Tashiro,∗1 T. Takabe,∗1 W. Sato,∗1 N. Takahashi,∗1
T. Yoshimura,∗1 T. Mitsugashira,∗2 H. Haba, S. Enomoto, and A. Shinohara∗1
In the chemistry of heavy actinide and transactinide,
the chemical isolation of a nuclide of interest is preferable. However, we cannot spend much time removing by-products, because of the short lifetimes of nuclides. Therefore, we need to obtain information on
their chemical properties in their separation process.
For this purpose, we have been developing a capillaryelectrophoresis (CE) system. CE enables us to separate the elements rapidly with a large number of theoretical stages. At the same time, the mobility of eachelement reﬂects their chemical properties such as thestrength of metal-ligand interaction. A scheme of oursystem is illustrated in Fig. 1.
An analyte is typically detected by the on-capillarydetection method,1,2) because the solution volume
treated by CE is limited to the order of 10 nL. However, it is quite diﬃcult to detect heavy actinide andtransactinide nuclides using this method, because wemust detect α particles emitted from the analyte nuclides, which cannot penetrate through the capillarywall. Therefore, we tried to use the fraction collection
method. The ion fractions coming out of the capillary
are transferred into collection vials in microliters of theelectrolyte solution.
The performance of CE with the fraction collecting
apparatus was investigated using lanthanide multitracers and some actinide tracers. Lanthanide tracers were
produced by the 197 Au (14 N, X) nuclear reaction in
the E3b course of RIKEN Ring Cyclotron, irradiating
197
Au targets with 135 MeV/nucleon 14 N ions. The
fused silica capillary with 60 cm in length and 75 µm
i.d. was used. The applied voltage was 30 kV in positive. The analyte was hydrostatically injected into
the capillary. The electrolytes were an aqueous solution of 12 mM α-HIB (α-hydroxyisobutyrate). For
these experimental conditions, we followed the procedure of Quang et al.3) Here, the pHs were adjusted
to 2.98, 3.48 and 4.01. The ionic fractions transferred

into collection vials were measured using Ge and Si
semiconductor detectors.
We assumed the equilibrium state of the following
metal-ligand reaction as
M3+ + nL−⇔

[MLn ](3−n)+ ,where L is α-HIB. The mobility of the metal cations decreases with the coordination number of the ligand, because the mean charge of the complex becomes smaller.
The electrogram of each experiment is shown in
Fig. 2. For every pH condition, the elements withsmaller ionic radius passed through the capillary fasterthan those with larger ionic radius. When ionic radius
is small, the surface charge is large in general. Therefore, the elements with smaller ionic radius seemed to
attract ligand anions more strongly.
Also, the mobility of the elements with smaller ionicradius, which interact with ligands strongly, decreased
with the increase in pH. At higher pH, the dissociationof ligand (α-HIB) is enhanced, and many metal cations
form bonding with ligand anions. This is the reason
why the mobility of these elements decreases with theincrease in pH.
Moreover, at higher pH, the peaks become broad asa result of the interaction between metal cation andcapillary wall. We are now trying to reduce this interaction treating the capillary wall.

Fig. 2. Variation fo electrogram with pH values. ◦: Ce, •:Am, △: Cm, ▲: Pm, □: Eu, ■: Gd, ▽: Y, ▼: Tm, ◇: Yb.
Fig. 1. Capillary electrophoresis/fraction collection apparatus for heavy actinide chemistry.
∗1
∗2

112

Department of Chemistry, Osaka University
Institute for Materials Research, Tohoku University

References
1) P. Janos: Electrophoresis 24, 1982 (2003).
2) S. L. Pentony et al.: Anal. Chem. 61, 1642 (1989).
3) C. Quang et al.: J. Chromatogr. A 659, 459 (1994).

RIKEN Accel. Prog. Rep. 39 (2006)

Development of gas-jet transport system for superheavy element
chemistry using the RIKEN K70 AVF Cyclotron
T. Takabe,∗ Y. Kitamoto,∗ D. Saika,∗ K. Matsuo,∗ Y. Tashiro,∗ T. Yoshimura,∗
H. Haba,∗ D. Kaji, and A. Shinohara∗
A gas-jet transport system for superheavy element
chemistry was installed at the C-03 beam line of the
RIKEN K70 AVF Cyclotron. The gas-jet system has
been widely used for delivering short-lived superheavy
element nuclides, because its transport time is in theorder of one second from the target chamber to various
devices. In this work, the performance of the present
system was investigated using W isotopes produced in
the nat Gd(22 Ne,xn) reaction.
A schematic of the system is shown in Fig. 1. Anat
Gd target of 0.18 mg/cm2 thickness and 7 mm diameter was prepared by the electrodeposition onto aberyllium backing foil of 2.0 mg/cm2 thickness. The
144-MeV 22 Ne7+ beam from the RIKEN K70 AVF
Cyclotron passed through a beryllium vacuum window(1.9 mg/cm2 ), a helium cooling gas (0.13 mg/cm2 ), andthe target backing. Finally, the beam entered the target material at 122 MeV. The average beam intensity
was approximately 300 particle-nA (pnA). The reaction products recoiled out of the target were stopped
in helium gas (∼90 kPa), attached to KCl aerosol particles generated by the sublimation of KCl powder, andwere transported through a Teﬂon capillary (2.0 mm
diameter, 10 m long) to the E7 irradiation room justbeneath the C-03 beam line. They were collected ona glass ﬁlter (ADVANTEC GB-100R) and subjectedto γ-spectrometry using an HPGe detector. In a separate experiment, all of the products recoiled out of
the target were directly collected using an Al catcher
foil (99.999% in purity) of 10 µm thickness placed justbehind the nat Gd target. Thus, the gas-jet transport
eﬃciency was deduced from the activities in the glassﬁlter and Al catcher foil.
The optimum condition of the gas-jet system wasﬁrst investigated as a function of the temperatureof the KCl aerosol generator from 580◦ C to 640◦ C.
It was found that the gas-jet transport eﬃciency increases with an increase in the temperature of the KClaerosol generator and attains a plateau value at about620◦ C. The gas-jet transport eﬃciency increases proportionally to the helium gas ﬂow rate from 3 L/min
to 5 L/min. Under the condition of the He-gas ﬂow
rate at 5 L/min, the inner pressure of the target chamber is almost equal to the pressure of the atmosphere.
Thus, the temperature of the KCl aerosol generator of620◦ C and the helium gas ﬂow late of 4.5 L/min were
determined as the optimum conditions. Under these
conditions, the gas-jet transport eﬃciency was approximately 17%. The dependence of the gas-jet transport
eﬃciency on beam intensity was also studied, because
recently available high-intensity beams cause a serious
problem in that the plasma created by these beams
drastically decreases the gas-jet transport eﬃciency.
In Fig. 2, the gas-jet transport eﬃciencies of 173 W,
24,25
Na, 28 Al, and 27 Mg are shown as a function of
the beam intensities from 50 pnA to 300 pnA. The isotopes of 24,25 Na, 28 Al, and 27 Mg were produced in theinteraction between the 22 Ne beam and the beryllium
backing foil. As shown in Fig. 2, no decreasing trendof the gas-jet transport eﬃciency was observed up to
the beam intensity of 300 pnA.
In the near future, we will perform an experimentto produce 255 No by the 238 U(22 Ne,5n)255 No reaction
using the RIKEN K70 AVF Cyclotron.

Fig. 1. Schematic of gas-jet transport system.
∗

Department of Chemistry, Graduate School of Science,
Osaka University

Fig. 2. Gas-jet eﬃciency as function of beam current.

113

RIKEN Accel. Prog. Rep. 39 (2006)

Distribution coeﬃcients measured with noncarrier tracers of
Zr-88 and Hf-175 on TBP resin in hydrochloric acidand nitric acid solutions
A. Yokoyama,∗1 S. Kamataki,∗2 K. Morishita,∗2 and H. Haba
Research on the chemical properties of transactinides has gathered considerable attention in spiteof experimental diﬃculties in fulﬁlling several requirements for measurement such as a quick equilibration
at ultralow concentration, that is, in the extreme
case, one-atom-at-a-time chemistry, or in other words,
single-atom chemistry.1) Distribution coeﬃcients ofrutherfordium, Rf, in liquid-liquid systems are being
investigated because of the lack of such data and contradiction between earlier data.2)
In this study, distribution coeﬃcients, Kd , of Zr andHf that are homologues of Rf, were measured with
noncarrier tracers of Zr-88 and Hf-175 on TBP resin
in hydrochloric acid and nitric acid solutions in order to present data that can be compared with thoseof rutherfordium in a solvent extraction system andalso to discuss the dependence of the properties on theconcentration of the relevant chemical species and theapplicability of the rutherfordium experiment.
The TBP resin that an organic solvent of tributylphosphate (TBP) was attached to, aimed at rapid
chemical procedures for the rutherfordium experiment,
was prepared for this study as follows. The resin wasmade of MCI GEL CHP20Y, Mitsubishi Chemical Corporation, a styrenedivinylbenzen copolymer of about
30 µm in particle size used as a supporting material,
which was washed beforehand with methanol and acetone and dried at 110◦ C in a vacuum oven for 6 hours
and weighed. Then, the resin was suspended in stirred
methanol solution, while TBP was added in drops up
to 20% of the resin in weight. After stirring and heating under an IR lamp until methanol was removed, theresin was again dried at 110◦ C in the vacuum oven for
6 hours and weighed.
The carrier-free radiotracers of Zr-88 and Hf-175
were produced in the 89 Y(p,2n) and the 175 Lu(p,n) reactions, respectively, using 20-MeV protons from the
AVF cyclotron of Research Center for Nuclear Physics,
Osaka university. In addition, multitracers from a Au
target including Hf-175 and multitracers from a Ag
target including Zr-88, which are very useful in crosschecking the data because the distribution coeﬃcientsare determined simultaneously for many nuclides, were
produced at RIKEN. For both cases, the target material was chemically separated to produce carrier-freetracer solutions.
∗1
∗2

114

Graduate School of Natural Science and Technology,
Kanazawa University
Faculty of Science, Kanazawa University

The batch method was applied to the measurement
by using the tracers mentioned above. The TBP resinof 5 to 200 mg was placed in a polypropylene tube witha cap and 25 to 200 µL of Zr-88 and Hf-175 tracer solutions with hydrochloric acid or nitric acid were added
so as to produce 3 mL of solution in total. The tube
was shaken for 10 minutes, centrifuged for 3 minutes,
and 1 mL aqueous solution was pipetted into anothertube and assayed by γ-ray spectrometry.
In Figs. 1 and 2, it is shown that the measured values are consistent with each other as a general trend
except for the Hf data at a high concentration of hydrochloric acid, and they are larger than the data in aprevious report3) at the ordinary concentration of Zr
and Hf atoms by one order of magnitude although they
have similar tendencies as functions of the acid concentrations of HCl and HNO3 . It was concluded that thesolution system of nitric acid in the range from 6 to
8 M may be promising for the measurement of Rf due
to Kd values appropriate for the measurement and theinteresting discrepancy between Zr and Hf.

Fig. 1. Distribution coeﬃcients of Zr and Hf (on TBP
resin) in nitric acid measured with single tracers andmultitracers.

Fig. 2. Distribution coeﬃcients of Zr and Hf (on TBP
resin) in hydrochloric acid measured with single tracers and multitracers.

References
1) D. Trubert and C. Le Naour: in The Chemistry of Superheavy Elements, edited by M. Schädel (Kluwer Academic Publishers, Dordrecht, 2003), p. 95.
2) H. Haba, K. Tsukada, K. Akiyama, M. Asai, A.
Toyoshima, Y. Ishii, S. Enomoto, and Y. Nagame:
RIKEN Accel. Prog. Rep. 38, 107 (2005).
3) M. Takaka and H. Akaiwa: in Yobai Chushutsu Kagaku(Shokabo, Tokyo, 2001), pp. 247, 249.

RIKEN Accel. Prog. Rep. 39 (2006)

Eﬀects of milk and soy milk on uptake of trace elements in rats
Y. Nakanishi,∗ M. Suzuki,∗ M. Hasama, T. Ando,∗ M. Ozaki,∗ H. Haba, S. Enomoto,∗ and S. Kimura∗
The National Nutrition Survey 2002 showed that
intakes of calcium and iron are not suﬃcient in theJapanese population, especially young women. Recent
studies suggest that there is a relationship between
previous milk consumption and bone mass in young
women.1) Soy milk consumption may be eﬀective in
reducing bone loss in postmenopausal women becauseof the estrogenic properties of soy isoﬂavone.
Iron absorption may be inhibited by the high intakesof calcium. Since calcium inhibits both heme and nonheme iron absorption, Hallberg et al. suggested thatthe inhibition is occurring in the intestinal mucosal
cells where calcium interferes with iron transport.2) On
the other hand, the components of milk, such as casein
phosphopeptides are suggested to enhance mineral absorption. Further studies are necessary to clarify theinteraction of milk consumption and iron absorption
and storage. Thus, to investigate the eﬀect of milk
and soy milk on the absorption of various elements, we
determined the uptake rates of trace elements in rats
using a multitracer technique.
The multitracer solution was prepared from a
Ag target irradiated with a heavy-ion beam of
135 MeV/nucleon accelerated in the RRC. 59 FeSO4 solution was purchased and added to the multitracer solution. The detailed procedure for preparing the multitracer solution was described previously.3)
The rats were orally administered multitracer solution and distilled water (DW), milk and soy milk. The
rats were kept in cages and sacriﬁced 3, 7 and 24 hafter the administration of test solution. Then, theliver and blood were collected. Serum was separated
by centrifugation (3000 rpm for 10 min). The radioactivities of the liver and serum were measured using
high-purity Ge detectors and the γ-ray spectra wereanalyzed. Data were statistically analyzed by two-way
ANOVA.
The rate of Fe uptake in serum in rats administered∗with milk and soy milk was signiﬁcantly lower thanthat in rats administered DW (p < 0.001 with twofactor interaction) (Fig. 1). The rates of Se, Co and
Mn uptakes in serum in rats administered soy milk
were signiﬁcantly lower than those in rats administered
DW (p < 0.01) There was no signiﬁcant diﬀerence inthe rates of trace element uptake in the liver.
The results were consistent with the hypothesis thata high calcium intake inhibits iron absorption. In addition, soy milk was shown to be a strong inhibitor oftrace element absorption.
Both milk and soy milk did not inﬂuence the uptakeof iron in the liver of normal rats. Further studies
regarding of the uptake rates of iron and calcium iniron-deﬁcient rats are necessary.

Fig. 1. Incorporation of Fe, Se, Co and Mn into serum.

References
1) D. Teegarden et al.: Am. J. Clin. Nutr. 69, 1014 (1998).
2) L. Hallberg et al.: Eur. J. Clin. Nutr. 46, 317 (1992).
3) S. Ambe et al.: Anal. Sci. 7, 317 (1991).

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

115

RIKEN Accel. Prog. Rep. 39 (2006)

Influence of dopamine on overaccumulation of copper in LEC rats:
A proposal
M. Hasama, S. Kimura,∗ and S. Enomoto
Wilson’s disease (WD)-related neuropathy is characterized by extrapyramidal dysfunction such as involuntary movement and salivation.1) WD exhibits copper (Cu) overaccumulation in liver with varied clinicalmanifestations, and many cases with WD have severe
extrapyramidal dysfunction. In order to better understand the etiology of this disorder, diﬀerent animalmodels of WD have been proposed. Among them, aged
Long Evans Cinnamon (LEC) rats have been widely
studied because they show several forms of Cu overaccumlation in the brain.
The hepatic Cu accumulation seen in LEC rats also
occurs in WD patients. LEC rats also show an ironoverload in the liver and the brain.2) It is well known
that Cu and iron accumulations increase the eﬀects ofaging, and these accumulations might have deleterious
eﬀects on the liver and the brain via oxidative stress.
Furthermore, Cu and iron accumulation in the brain
may aﬀect the metabolism of other elements. Zinc andmanganese may be of particular relevance in LEC rat
brain because these elements play a role in reactive
oxygen removal from the brain.
For this study, a radioactive multitracer technology,
which enables simultaneous tracing of a number of elements, is applicable. The radioactive multitracer technology was developed at RIKEN and is widely used intrace-element studies. A multitracer solution is obtained from a target that has been irradiated withhigh-energy heavy irons. Using the multitracer prepared from an Ag target irradiated with a 14 N beam,
it was possible to examine the distributions of 13 traceelements in the brain.
In this study, LEC rats were given unilateral intrastriatal stereotaxic injections of multitracer as part ofthe microdialysis method. The microdialysis technique
is commonly and widely used for the biochemical analysis of interstitial ﬂuids in various tissues. The purposeof this method is to identify several theoretical models∗

116

Graduate School of Human Life Science, Showa Women’s
Universitythat take into account both the diﬀusional resistances
encountered in vivo and the eﬀects of various active
processes, such as metabolism, release and uptake, andtransport across the blood brain barrier.
The microdialysis method is described below. LEC
rats were anesthetized and placed in a stereotaxic apparatus. The skull was exposed, and a small hole wasdrilled on one side. The microdialysis probe, an intercellular lymph dialyzer, is implanted vertically inthe striatum (coordinates: anterior: +1.0 mm frombregma, lateral: +3.0 mm from midline and vertical:−3.6 mm from dura), according to the atlas of Paxinos and Watson.3) After the recovery phase, artiﬁcial
cerebrospinal ﬂuid (ACSF) in which multitracer was
dissolved is injected into the striatum. In addition,
striatal dopamine is quantiﬁed in time. Finally, theprobes are removed and the brains are cut on a Vibratome in serial coronal slices. The sliced samples
are subjected to γ-ray spectrometry with pure Ge detectors, set in reference to an appropriate standard,
to determine the percentage of diﬀerent tracers in theinjected dose.
This method is discussed in relation to the traceelement metabolism in each brain area, together witha discussion of the striatal dopamine concentration.
The extrapyramidal dysfunction, WD-related neuropathy, stems from an abnormal striatal dopamine
system.4) We also investigate the change of striatal
dopamine concentration induced by nerve stimulus,
such as high K+ .
References
1) H. Shim et al.: J. Nutr. 133, 1527S (2003).
2) D. W. Kim et al.: Neurochem. Res. 30, 475 (2005).
3) G. Paxinos et al.: The Rat Brain Stereotaxic Coordinates (Academic Press, New York, 1987).
4) H. Barthel et al.: Eur. J. Nucl. Med. Mol. Imaging. 28,
1656 (2001).

RIKEN Accel. Prog. Rep. 39 (2006)

Investigation of Cu dynamics in Long-Evans Cinnamon rats
A. Nakayama,∗1 H. Yasui,∗2 H. Sakurai,∗2 H. Haba, and S. Enomoto
Long-Evans rats with a cinnamon-like coat color(LEC rat) develop hepatitis at approximately 4 months
after birth due to an unusual accumulation of Cu in
their liver.1) An excess of Cu exhibits leads of cytotoxity and usually induces the production of somemetal-binding proteins such as metallothionein (MT)to protect organs against Cu-induced cell damage. MT
binds to metals to maintain homeostasis or to detoxify
heavy metals, but Cu-binding MT reacts with hydrogen peroxide to generate hydroxyl radicals, which inturn leads to hepatic disorders.2) On the other hand,
it has been reported that organisms have developed
sophisticated mechanisms of maintaining the balance
between essential and toxic Cu levels.3) Within cells,
Cu is distributed to speciﬁc subcellular components
or proteins by Cu chaperones that include Rah1 and
ATP7A/B, which delivers Cu to ceruloplasmin, Cox17,
which delivers Cu to mitochondrial CCO, and CCS,
which inserts Cu into Cu, Zn-SOD.
However, Cu kinetics in the body and cells of LEC
rats has not yet been clariﬁed suﬃciently. One of thesolution for this is the evaluation of copper kinetics
using a radioactive tracer, because the utilization ofa radioactive Cu isotope is generally diﬃcult. Thus,
Nakayama et al. attempted to produce 67 Cu with thelongest half-life (t1/2 = 61.7 h) among radioactive Cu
isotopes and to investigate the intracellular Cu kinetics
using 67 Cu.
67
Cu was produced via the 70 Zn(p, α) reaction.4)
In brief, an enriched 70 Zn target (80%) was irradiated with a 0.96 µA proton beam (proton energy:
12.8 MeV) for 1 h and 67 Cu was separated from theunreacted target and by-products, 67 Ga and 56 Co, byanion-exchange chromatography. The resulting solution containing 67 Cu was heated to dryness and stored
until use. The dried 67 Cu was completely dissolved ina small amount of 1 M HCl and diluted with PBS. The
67
Cu-containing solution was intravenously (iv) and intraperitoneally (ip) injected into 9-, 15-week-old, andaged LEC rats and 10-week-old Wistar (used as control) rats. After 2 h, we collected the liver, kidney,
and blood, and then measured in the radioactivities.
A portion of each liver was used to produce cytosol,
which was subjected to SDS-PAGE and analyzed forthe intracellular distribution of 67 Cu using a bioimaging analyzer.
Figure 1 shows organ (A) and intracellular (B) 67 Cu
distribution after iv administration. The results of ip
administration were similar to those of iv administra∗1∗2

Devision of Medicine, Vanderbilt University Medical Center,
USA
Department of Analytical and Bioinorganic Chemistry,
Kyoto Parmaceutical University

Fig. 1. 67 Cu distribution (A) to the blood, liver and kidneyof the 9-, 15-week-old and retired LEC and Wistar ratsand (B) to the intracellular Cu-containing proteins in
the liver cells of 9-, 15-week-old and retired LEC andWistar rats. The insert is the expanded ﬁgure of the
distribution to blood. ∗ means signiﬁcant diﬀerence atthe level of p < 0.05.

tion. The 67 Cu distribution was approximately four
fold higher in the liver and two fold lower in the bloodof LEC rats than in those of Wistar rats. These results suggest that the administrated Cu was immediately distributed from the blood and accumulated in
the liver of LEC rats. The intracellular 67 Cu distribution showed that the 67 Cu distribution for MT was
signiﬁcantly higher and that for Rah1 was signiﬁcantly
lower in the hepatic cells of LEC rats than in those of
Wistar rats. These results were consistent with previous reports.5,6) The distribution for CCS was lower inthe livers of 9-week-old LEC rats than in those of theother rats, whereas the distribution for SOD was almost the same. Although the reason and role of the decreased distribution for CCS are unknown at present,
this might be related to the development of hepatitis.
References
1) M. Sasaki et al.: Rat News Lett. 14, 4 (1985).
2) H. Sakurai et al.: Biochem. Biophys. Res. Commun.
184, 1393 (1992).
3) M. Marjorette et al.: J. Biol. Chem. 275, 33244 (2000).
4) D. J. Jamriska et al.: J. Radioanal. Nucl. Chem. 195,
263 (1995).
5) A. Nakayama et al.: J. Trace Elem. Exp. Med. 15, 31(2002).
6) J. Wu et al.: Nat. Genet. 7, 541 (1994).

117

RIKEN Accel. Prog. Rep. 39 (2006)

Diﬀerence in property of skin penetration between 65 Zn(II) ion andits complex topically applied on skin of live hairless mice
H. Yasui,∗ H. Nishimura,∗ H. Haba, S. Enomoto, and H. Sakurai∗
Zinc (Zn), with an atomic number of 30 and an
atomic weight of 65.37, is one of the most important essential trace elements found in all living systems. This
metal is necessary as a catalytic component for morethan 200 enzymes and is also a structural componentof many proteins, hormones, neuropeptides, and hormone receptors.1) Among the many pharmacologicaland nutritional roles of Zn(II), its anti-inﬂammatory
activity has been well known for a long time.2) Zincoxide (ZnO) is clinically used in many countries as ananti-inﬂammatory agent for the treatment of wounds.
Recently, we have found that the supplementation oforal Zn(II) and its complex to alive hairless mice exposed to UVA prevents skin damage.
On the basis of these results, we examined whether
Zn(II) applied topically on the skin of alive hairless mice exhibits antioxidative activity against reactive oxygen species (ROS) generated in UVA-exposed
skin.3) When ZnCl2 was topically applied on the skinsurface of mice at a dose of 40 µg Zn/5 cm2 before UVA
exposure (18 J/cm2 ), ROS level in UVA-exposed skinsigniﬁcantly decreased. However, when ZnCl2 was applied at the same dose for 30 min and then removed
immediately before UVA exposure, the eﬀect of ZnCl2
application disappeared. We then prolonged the application time from 30 to 60 and 180 min and observed
the eﬀects of Zn(II). Even after the removal of ZnCl2
applied ZnCl2 for 60 and 180 min, ROS levels further
decreased to the level of the control. These results indicate that (1) ZnCl2 does not act as a ﬁlter for UVA
light and that (2) ZnCl2 might induce some antioxidative enzymes or proteins that were synthesized fora short time such as 60 or 180 min. On the basis of
the ﬁnding of the protective eﬀect of ZnCl2 against
skin damage in regard to the ROS suppressive eﬀect inalive UVA-exposed mice, we topically applied Zn(pic)2(bis(picolinato)Zn(II) complex), with a partition coefﬁcient of 0.02 in an octanol-saline system at 37◦ C,4)
at the same dose as that of ZnCl2 ; however, its antioxidative eﬀect signiﬁcantly decreased in comparison
with ZnCl2 . Thus, it is necessary to ﬁnd the causative
factors for the diﬀerence in antioxidative activity between ZnCl2 and Zn(pic)2 . First, we examined in thisstudy the features of skin penetration of ZnCl2 andZn(pic)2 by monitoring 65 Zn(II) level after the topicalapplication of 65 Zn-labeled compounds.
65
Zn in the chemical form of ZnCl2 in 0.5 mol/L HCl,
was obtained from RIKEN. 65 Zn solution was slowly
dried and then the residue was redissolved in a saline∗

118

Department of Analytical and Bioinorganic Chemistry,
Kyoto Pharmaceutical University(activity = 370 kBq/mL). ZnCl2 dissolved in distilledwater was mixed with 37 kBq of 65 Zn to a ﬁnal volume of 1 mL. While Zn(pic)2 and picolinic acid (2% ofcomplex) dissolved in phosphate buﬀer (pH 7.8) weremixed with 37 kBq of 65 Zn, the buﬀer was added to the
preparation to a ﬁnal volume of 1 mL. The preparation
was then labeled with 65 Zn by allowing the preparation to stand at 25◦ C overnight. The next day, 1 mL ofethanol was added to 1 mL of each 65 Zn-labeled solution to a ﬁnal volume of 2 mL with 50% ethanol-water
solution. The radioactivity applied to each mouse
was 0.925 kBq of 65 Zn/2.5 cm2 . Female hairless mice
(10–12 weeks old), weighing 25 g, were administered
50 µL of 50% ethanol-water solution of 65 ZnCl2 or
65
Zn(pic)2 by a single topical application at a dose of
20 µg Zn/2.5 cm2 . After the treatment (30–180 min),the mice were sacriﬁced under anesthesia with ether
and the applied area of the skin was removed. The
stratum corneum was immediately removed by tapestripping 5 times using Scotch mending tape, and theremaining skin as the sum of the epidermis and dermis was weighed and transferred to polyethylene tubes
for analysis using a gamma counter. Radioactivity due
to 65 Zn incorporated in the epidermis and dermis wascounted with an Aloka ARC-360 autowell gamma system using the peak area of 1115.5 keV due to the 65 Zn
nucleus as reference. Consequently, 65 ZnCl2 was foundto penetrate more eﬃciently into the skin tissue than
65
Zn(pic)2 at 1% signiﬁcant diﬀerence level (see Fig. 1).
This feature seems to be due to the higher contributionof the polar route to transporting a 65 Zn-labeled compound through the stratum corneum layer, providing
a new approach to treatment with Zn compound.

Fig. 1. Penetration of 65 ZnCl2 (open bar) and 65 Zn(pic)2(closed bar) into epidermis and dermis of hairless mice.

References
1) A. S. Prasad: Nutr. Rev. 41, 197 (1983).
2) M. S. Ågren: Acta Derm. –Venereol. 71, 153 (1991).
3) H. Sakurai, H. Yasui, K. Mishina, and H. Nishimura:
Biomed. Res. Trace Elem. 14, 27 (2003).
4) Y. Yoshikawa, E. Ueda, K. Kawabe, H. Miyake, T.
Takino, H. Sakurai, and Y. Kojima: J. Biol. Inorg.
Chem. 7, 68 (2002).

RIKEN Accel. Prog. Rep. 39 (2006)

Behavior of trace elements and protein contents in livers ofzinc-deficient mice
R. Minayoshi,∗1 T. Ohyama,∗1 N. Kinugawa,∗1 J. Kamishima,∗1 M. Noguchi,∗2 K. Ishikawa,∗2
H. Suganuma,∗1 K. Takahashi, S. Enomoto, and M. Yanaga∗1
Previously, the concentrations of zinc and othertrace elements in various tissues of Zn-deﬁcient mice
were determined by INAA to investigate the physiological eﬀect of Zn deﬁciency on the concentrations ofother elements in mice.1) No signiﬁcant diﬀerences between Zn-deﬁcient and normal mice were found in thezinc concentration of liver. On the other hand, theconcentration of Co increased in all the tissues of Zndeﬁcient mice. Then, the following two studies werecarried out to investigate the behavior of trace metallic
elements bound to proteins. One is the determinationof the concentrations of trace elements and proteins after gel ﬁltration chromatography for cytosolic fractionof hepatocytes. The other is the investigation of aﬃnities between metals and proteins, which are containedin these fractions.
Eight-week-old male mice of ICR strain were divided
into two groups; one group was fed a Zn-deﬁcient dietand ultrapure water (Zn-def. mice), and the other one
fed a control diet and the same water (control mice).
After three weeks, their livers were removed and immediately weighed. Every eight livers of each group
was together homogenized and separated into two subcellular fractions, such as supernatant (cytosolic fraction) and other fractions, by ultracentrifugation. The
cytosolic fraction was further divided into forty fractions (2 ml per fraction) by gel ﬁltration chromatography (Sephadex G-100) using Tris-HCl buﬀer (pH 7.4)
as eluent, at a ﬂow rate of 10 ml/h, at 4◦ C. Then,the concentrations of the metallic elements and proteins in each fraction were determined by ICP-MSand BCA protein assay, respectively. In accordancewith the results of ICP-MS, the 12th–19th fractions,in which the concentrations of zinc decreased, wereused for the following experiments. Proteins in thesefractions were further separated with SDS-PAGE. The
gel was stained with silver stain. Multitracer solution
was added to the 14th–16th fractions to investigate theaﬃnities between the trace elements and metalloproteins, and incubated for 1 h at 4◦ C to prevent denaturation and decomposition of proteins. Each solution
was poured into several centrifugal ﬁlter tubes, such as
Micron YM-3, -10, -30, and -50 (Millipore Co.), andcentrifuged at 2000 × g for 30 min. The radioactivities
in those samples were measured with HPGe detectors.
In each examination process, such as gel ﬁltration chro∗1∗2

matography, SDS-PAGE, and the multitracer experiment, the amounts of proteins in the samples for twogroups were adjusted to be equal to each other.
The zinc concentrations in the 13th–18th, 21st, and22nd fractions of Zn-def. mice were much lower, andthe cobalt concentrations in the 14th, 17th, 18th, 21st,and 22nd fractions were higher than the control ones.
On the other hand, the concentrations of proteins in
the 13th–15th fractions of Zn-def. mice were low. However, no signiﬁcant diﬀerences between Zn-def. andcontrol mice were found in the positions and numbersof protein bands of lanes on gel for the 12th–21st fractions.
The rates of radioactivities of 65 Zn, and 56 Co detected from the ﬁlters in the 14th fraction are shownin Fig. 1. The radioactivities detected from the ﬁlters
indicate the amounts of metal elements bound to proteins. The aﬃnities between 65 Zn and proteins over
30 kDa in the 14th fraction of Zn-def. mice decreased.
On the other hand, these were no diﬀerences between
two groups on the aﬃnities between 56 Co and proteinsin the 14th fraction. Furthermore, the result indicatesthat the size of cobalt aﬃnitic proteins is almost in thevicinity of 10 kDa, because the aﬃnities of over 10 kDa
were much lower than 3 kDa of each group.
These results may suggest that the zinc-binding proteins in a range of 10 kDa ≤ decreased or zinc replacedby the other metal elements, whereas the results of
SDS-PAGE showed that there was neither disappearance of metalloproteins nor induction of other proteins.

Fig. 1. Aﬃnities between proteins and 65 Zn, and 56 Co in
14th fraction.

ReferenceRadiochemistry Research Laboratory, Faculty of Science,
Shizuoka University
Department of Biology and Geosciences, Faculty of Science,
Shizuoka University

1) M. Yanaga, H. Wakasa, T. Yoshida, M. Iwama, K.
Shinotsuka, M. Noguchi, and T. Omori: J. Radioanal.
Nucl. Chem. 245 255 (2000), and references therein.

119

RIKEN Accel. Prog. Rep. 39 (2006)

Determination of rhenium and technetium in marine algae
T. Ishii,∗ T. Sakuragi,∗ H. Haba, and S. Enomoto
The diﬀerences of biological and chemical behaviors
between Re and Tc belonging to the same group in the
periodic table were examined from elemental analyses
with various separation procedures and bioaccumulation experiments.
Fifty species of marine organisms including algae (Bryospsis maxima, Sargassum thunbergii, Fucus
vesiculosus, Ascophyllum nodosum etc.) were collected
in Japan, Canada, Norway and UK.
The metallic 95 Mo target (Enrichment; 96.8%) with
0.01 mm in thickness from the Oak Ridge National
Laboratory was irradiated by a 8.8–14 MeV proton
beam using the RIKEN K70 AVF cyclotron, as shownin Fig. 1. 95m Tc was used to obtain the recovery or to
examine its behavior while chemical separations werecarried out. The radioactivity of 95m Tc produced in
the 95 Mo (p, n) reaction was 538 kBq/0.0055 g of 95 Mo.
The speciﬁc activity of 1.734 Bq/fg at mass number
A = 99 in enriched 95 Mo was much higher than that
(0.035 Bq/fg) of Mo having a natural abundance, as
shown in Table 1. If 173.4 Bq of 95m Tc is spiked as ayield monitor, only 5 ppq (100 fg/20 mL) is estimatedto enhance the intensity at A = 99. It was supposedthat an isotope at A = 99 mass was 99 Tc derived fromthe reactions such as 100 Mo(p, 2n), 100 Mo(n, 2n)99 Mo→ 99m Tc, 98 Mo(p, γ), and 98 Mo(n, γ)99 Mo → 99m Tc.1)

Prior to the determination of 99 Tc, 99 Tc in samples
was collected on a 3 M Empore 3292 Tc disk, an anion
exchange resin, an Eichrom TEVA resin and disk, andan activated charcoal.
Since the measurements of 99 Tc by ICP-MS was
supposed to be inﬂuenced by 98 Mo1 H+ and 99 Ru, almost all of Mo and Ru were removed by the TEVA
resin and the anion exchange resin. The concentrations of 99 Tc in ﬁnal volume of 20 mL were determinedby a ThermoFinnigan Element2 HR ICP-MS (Sensitivity; 750,000 cps/ppb, Detection limit; 31.4 fg/mL =20 µBq/mL).
Beta ray (βmax ; 293.7 keV) of 99 Tc on the Tc
disk was also measured by a PICOBETA PBS-1
Low-Background beta-ray spectrometer (Absolute detectable amount; 2 mBq) for 10,000–300,000 sec.
In the case of Re, 0.1–2 g of dry materials were wetdigested by H2 O2 and HNO3. The concentrations of
Re were measured by ICP-MS using an ACROS ORGANICS Re standard.
99
Tc concentrations diﬀered among sampling locations or species of organisms, as shown in Table 2. The
concentration of Re in green alga B. maxima was morethan one hundred timed higher than other species ofmarine algae.1)
Wide diﬀerences in biological and chemical behavior
were observed between Re and Tc. For example, it was
found from the results of elemental analyses and bioaccumulation experiments that the concentration factor
of Tc in F. vesiculosus was ten times higher than thatof Re.1)
Furthermore, Tc was not removed from the 3 M Empore 3292 Tc disk and Eichrom TEVA disk although
the majority of Re was eluted from collectors by 10 M
HCl solution.
Table 2. Comparison of 99 Tc concentration in marine algae collected from various sites.

Fig. 1. Mo targets used for producing 95m Tc.
Table 1. Comparison of the specific activity based on differences of proton energy and enrichment of Mo targets.

References∗

120

Research Center for Radiation Safety, National Institute ofRadiological Sciences

1) T. Ishii et al.: Proc. 2nd Int. Conf. on the Radioactivity
in the Environment, Nice, France, 2005-10, edited by P.
Strand (2005), p. 253.

RIKEN Accel. Prog. Rep. 39 (2006)

Search for metal delivery from nose to brain: A multitracer study
Y. Kanayama,∗ E. Hayashi,∗ H. Haba, S. Enomoto, and R. Amano∗
Because intranasal administration has a possibility
to provide a direct delivery route to the brain, it is expected as an eﬀective administration method for certain drugs or metals targeting the brain, in particular when such drugs or metals injected into the blood
are hardly delivered through the blood-brain barrier or
are toxic. For example, Mn2+ , well known as a neurotoxic element, can be delivered into the olfactory bulb
(OB) by the axonal transport of the olfactory neuron;
therefore, it is considered as an imaging agent of theneural pathway in Mn-enhanced MRI.1) The axonaltransport is slow, so the Mn2+ transport takes several days to reach the distant brain regions from OB.
On the other hand, we previously found the rapid olfactory transport of Tl+ , i.e., it was transported in
the OB within 3 h and was eliminated during 48 h after intranasal administration.2) This result indicatesthat there are other routes from the nose to the brain
aside from the axonal transport of the olfactory neuron. In some cases, the fast delivery, as in Tl+ , isdesired for diagnosis or therapy by intranasal administration. Therefore, more detailed information concerning the delivery of intranasally administered materials
is important. To search for a fast delivery route fromthe nose to the brain, a preliminary study of the accumulation of several metal ions in nasal-cavity-related
tissues using a multitracer was performed.
The multitracer was obtained from a Ag target according to the method of Haba et al.3) The multitracer
solution was administered into Wistar rats (male, 6week-old) intranasally (i.n.) and intravenously (i.v.).

At 6 and 24 hours, rats were sacriﬁced and the following 15 tissues were sampled: the blood, deep lateral cervical lymph nodes, superﬁcial lateral cervicallymph nodes, axillary lymph nodes, trigeminal nerve,
OB, olfactory cortices (piriform cortex, amygdala, andentorhinal area), hippocampus, striatum, cerebral cortex, brainstem (except the hindbrain), cerebellum,
pons, medulla oblongata, and spinal cord. After activities were measured, the uptake rates of each sample
were given as %dose/g wet weight.
Table 1 shows the uptake rates of 46 Sc, 48 V, 54 Mn,
65Zn, 75 Se, 83 Rb, 88 Y, 88 Zr, and 103 Ru in each sample 24 h after administration. In i.n. administration,
46
Sc, 54 Mn, 65 Zn and 83 Rb showed brain accumulations. It was found that 46 Sc was highly accumulated in the trigeminal nerve, brainstem, cerebellum
and pons. The higher uptake rates of 54 Mn and 83 Rb
in the OB after i.n. administration than those after i.v.
administration are considered to be due to the olfactory nervous transport.
Not to mention, further experimentation is needed
to describe the brain delivery route because of the limited number of samples in the present one. However,no fast delivery was observed except for 83 Rb at least
6 h after i.n. administration.
References
1) A. P. Koretsky and A. C. Silva: NMR Biomedicine 17,527 (2004).
2) Y. Kanayama et al.: Nucl. Med. Biol. 32, 505 (2005).
3) H. Haba et al.: Radiochim. Acta 93, 539 (2005).

Table 1. Tissue uptake rates of multitracer containing radionuclides 24 h after intranasal (i.n.) andintravenous (i.v.) administrations in rat. Data are calculated in terms of %dose/g for a rat.

∗

School of Health Sciences, Faculty of Medicine, Kanazawa
University

121

RIKEN Accel. Prog. Rep. 39 (2006)

Preliminary study of biodistribution of 203 PbCl2 and 203 Pb-DOTMP
in mice
K. Washiyama,∗ H. Haba, Y. Kanayama,∗ S. Enomoto, and R. Amano∗
Recently, α-particle-emitting nuclides have beenfound to be promising for targeted radionuclide therapy owing to the high linear energy transfer and shortpath length of α-particles in tissues.1) In addition tothese physical properties, some α-emitting nuclides
that are members of a decay chain release successive
α- and β-particles, and are called in vivo generators.2)
Cascade α-emission close to the target site is more effective for therapy than single α-emission.
In radionuclide therapy utilizing in vivo generators,
it is important to maintain the retention of daughter nuclides at the target site after the decay of theparent nuclide in addition to the selective accumulation of the parent nuclide to that site. Otherwise, thereleased daughter nuclides could be localized to othernormal tissues and may cause radiotoxicity. Therefore,
the pharmacokinetics of various daughter nuclides ismandatory in predicting and preventing radiotoxicity.
However, it is often diﬃcult to determine the accurate biodistribution of daughter nuclides owing to theirshort half-lives.
In this study, we produced a 203 Pb (T1/2 = 51.9 h)
tracer and evaluated the Pb biodistribution in the development of an alternative pharmacokinetic tracer inmice for 211 Pb (T1/2 = 36.1 m) and 212 Pb (T1/2 =10.64 h), which belong to the in vivo generators of223
Ra (T1/2 = 11.435 d) and 224 Ra (T1/2 = 3.66 d),respectively.
Macrocyclic phosphonate chelate 1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetramethylenephosphonic acid (DOTMP) is a well-known bone-targeting
agent and its application to the treatment of various bone-forming tumors or calciﬁed metastases has
been reported.3,4) DOTMP is excreted rapidly fromthe whole body into the urine just after administration.
Therefore, to prevent the radiotoxicity by Pb isotopes
during the use of in vivo generators for the treatmentof bone metastases, we also prepared a bone-targetinglabeled compound, 203 Pb-DOTMP, and evaluated its
biodistriution.
Lead-203 was produced via the 203 Tl (p, n) 203 Pb reaction by irradiating nat Tl2 O3 with 14 MeV protons at
the RIKEN K70 AVF cyclotron. Irradiation was performed at 4.5 µA for 2 h. After irradiation, the target
was left to stand for 4 days to allow the decay of theshort half-life radionuclides, 204m Pb (T1/2 = 67.2 m)
and 202m Pb (T1/2 = 3.62 h). The target was dissolvedin 2 mL of 8 M HNO3 and the solution was heated todryness, and then 1 mL of 1 M HCl was added. The∗

122

Graduate School of Medical Sciences, Kanazawa University

solution was loaded onto an anion exchange column(DOWEX 1 × 8) and 203 Pb was passed through thecolumn with 1 M HCl while the target material was
retained on the column. The eluate was evaporated
to dryness and then 2 mL of 0.1 M HCl was added toprepare a stock solution. One milliliter of the stock
solution was evaporated to dryness and 1 mL of saline
was added to the residue to prepare a 203 PbCl2 solution. The residual 1 mL stock solution was mixed with
DOTMP and adjusted to pH within 7–8 by adding
1 M NaOH and heated at 80◦ C for 15 min to preparea 203 Pb-DOTMP solution.
Male 13-week-old ICR mice were administeredwith 100 µL of 203 PbCl2 solution (0.9 kBq) or 203 PbDOTMP solution (1.0 kBq) via the tail vein. Eachmouse was sacriﬁced and dissected 15 min, 30 min,
1 h, 3 h, and 6 h after injection of 203 PbCl2 or 203 PbDOTMP. The blood, lung, liver, spleen, stomach,large intestine, small intestine, kidney, muscle, cardiac
muscle, and femur were excised and weighed. Each tissue sample was subjected to γ-ray spectrometry. The
uptake of 203 Pb was determined using 279.2 keV γ-ray.
The results are expressed as percent injected dose pergram (%ID/g) of tissue.
The uptake rate of 203 PbCl2 showed the same trend
as the already reported results.5) The skeletal uptake
rates of 203 PbCl2 and 203 Pb-DOTMP were comparable and increased with time. On the other hand, theuptake rates of 203 Pb-DOTMP in the other excised
tissues signiﬁcantly decreased compared with those of
the 203 PbCl2 at more than 6 h. In the kidney, although the uptake rate 15 min after administration was
30.7%ID/g for the 203 PbCl2 administration, it was signiﬁcantly reduced to 3.8%ID/g for the 203 Pb-DOTMP
administration.
In conclusion, the cyclotron production isotope
203
Pb will provide an accurate biodistribution of Pbmediated radiopharmaceuticals and perhaps give moredetailed pharmacokinetic information on 211 Pb and212
Pb generated in vivo.
References
1) M. R. McDevitt et al.: Eur. J. Nucl. Med. 25, 1341
(1998).
2) M. R. McDevitt et al.: Science 294, 1537 (2001).
3) S. P. Hassfjell et al.: Nucl. Med. Biol. 24, 231 (1997).
4) G. Henriksen et al.: Anticancer Res. 24, 101 (2004).
5) S. Z. Lever and U. Scheﬀel: Neurotoxicology 19, 197(1998).

RIKEN Accel. Prog. Rep. 39 (2006)

Comparative study of biotrace elements in bile of rat
under oxidative stress
K. Endo, Y. Sakuma,∗ K. Matsuoka,∗ C. Honda,∗ K. Matsumoto,∗ and S. Enomoto
It was demonstrated in a previous study that thetime course of trace elements in the abdomen can bemonitored by noninvasive measurement in the combined use of a well-collimated lead slit and a Ge semiconducting detector.1) In this study, the excretion
rates of biotrace elements in the bile of Se-deﬁcient andnormal rats were examined using the multitracer (MT)technique to improve reproducibility.2) We compared
the results obtained using MT with those obtained byinstrumental neutron activation analysis (INAA).
Wistar female rats that were on the 15th day of pregnancy were fed Se-deﬁcient (SeD) diet (Oriental Yeast
Co., Ltd.) and ultrapure water. Newly born rats wereremained with their own mothers for four weeks. Fourweeks after birth, young rats were weaned, and thenfed on SeD diet and ultra-pure water until experiments.
Male rats were used for experiments at 8 weeks old
as the SeD group. Normal male Wistar rats old as
the SeD group were purchased and used as the normal
control group. MT solutions were prepared using silver
foil irradiated with N-14 beams of 135 MeV/nucleon at
the RIKEN–Ring Cyclotron.
The biliary duct of a Wister rat was cannulated witha polyethylene tube under Nembutal-induced anesthesia. A saline solution containing MT was injected intravenously to SeD and normal rats. After the administration of MT solution (200 µL), bile samples werecollected in a polyethylene tube every 5 min, the γ-ray
spectra of each fraction were measured. To determine
the contents of stable elements in the bile samples fromnormal and SeD rats, the bile samples from normal and
SeD rats were analyzed by INAA at JRR-4 in Japan
Atomic Energy Research Institute (JAERI).
The excretion rates of Se, Sr, As, Mn, Co, and V
in the bile of Se-D and normal rats were estimatedfrom γ-ray spectra. The radioactivity of each nuclide
increased and reached a plateau about 20 min after administration. The excretion rate of Se into the bile of
Se-D rats was about 1/5 lower than that in normal rats.
Although the excretion rates of metal ions into the bileof Se-D and normal rats were measured within 60 min∗

after administration, no radioactivities of Fe and Zn
were detected in this time range. This indicates thatboth elements were absorbed and accumulated in theliver, while other elements were excreted into bile. It
is known that Fe(III) binds to transferrin in blood andresulting complex is transferred to the liver, spleen,
and/or bone marrow by blood circulation, where Fe
ions are stored as ferritin in liver.
Heme metabolism is an important for iron because
many proteins contain heme as a prosthetic group.
When these hemoproteins turn over, the heme is notrecovered, but is degraded. New heme is synthesized
for their replacements. In liver, heme-iron is metabolized, and the iron ions are excreted into bile and reabsorbed in duodenum, the eﬀective half-life of Fe is 70
days in animals. Therefore, the radioactivity of 59 Fe
was not observed within the time range in this study.
Nearly 70% of Zn binds to albumin, and 30% of themetal to α-macroglobulin in blood. It is stored as Znmetallothionein in liver. Zn is used for active centersof many enzymes. Therefore, 65 Zn is also not excreted
into bile immediately after the administration of MT.
The contents of Fe and Zn in bile were determinedby INAA. The results indicated that Fe and Zn were
found in the bile of both normal and SeD rats. The
contents of Fe in normal and SeD rats were nearly thesame (17–20 mg/kg dried bile weight), and those of Zn
were 0.4 mg/kg dried bile weight for the normal group,and 1 mg/kg dried bile weight for the SeD group. The
comparison of data obtained by the MT technique andthose by INAA may lead us to conclude that Fe detected by INAA in the bile of rats is a metabolite ofheme-iron, and that stable Zn detected in bile by INAA
is also metabolite from the liver.
References
1) K. Matsumoto et al.: Biol. Pharm. Bull. 28, 2029
(2005).
2) K. Endo et al.: RIKEN Accel. Prog. Rep. 38, 120(2005).

Showa Pharmaceutical University

123

RIKEN Accel. Prog. Rep. 39 (2006)

Eﬄux study of trace elements in a cisplatin-resistant lung cancer cellline using a multitracer techniqueT. Suzuki,∗1 T. Togawa,∗1 A. Yumoto,∗1 M. Takahashi,∗1 K. Nishio,∗2 H. Haba, S. Enomoto, and S. Tanabe∗1
The molecular mechanism underlying cisplatin resistance has been revealed to be “multi-functional,”
involving a decreased accumulation, an enhanced intracellular detoxiﬁcation and an increased DNA repair
ability. The decreased accumulation of cisplatin wasobserved in non-small cell lung cancer (NSCLC) celllines resistant to cisplatin. There is a good correlation between the intracellular amount of platinum andsensitivity to cisplatin. This observation suggests that
intracellular accumulation is a major determinant of
cisplatin resistance, at least in NSCLC. Previously,
it was reported that cisplatin enters cells in an ATPdependent manner. Further more it was reported that
cisplatin is eﬄuxed by multidrug resistance proteins(MRPs) as a glutathione conjugate.1) On the other
hand, certain metals, such as arsenite and cadmium,are eﬄuxed from cells in the same ATP-dependent
manner. Therefore, the contribution of these transporters is important for metal detoxiﬁcation analysis.
However, the molecular mechanisms underlying metaltransport, such as uptake and eﬄux transporters, areunclear.
In this study, to investigate whether metal transporters are up-regulated in cisplatin resistant cell line,
we determined the percentage of eﬄux of various metals from cisplatin-resistant cell lines using a multitracer(MT) technique.
We developed this new method for eﬄux analysis
and used the human NSCLC cell line PC-9 and its
cisplatin-resistant subline, PC-9/CPr. The cells weregrown in RPMI1640 supplemented with 10% FBS. A
radioactive MT solution was obtained from an Ag target irradiated in the RIKEN Ring Cyclotron, and it
was prepared as a physiological saline solution. The
MT solution was then added to the cells in a serumfree medium and incubated at 37◦ C for 2 hr (uptake of
MT). After incubation, the MT solution was removed
and the cells were washed with the same medium.
Then, a medium containing FBS was added and thecells were further incubated at 37◦ C for 1, 2 or 4 hrs.
After incubation, an aliquot of the culture medium wascollected and analyzed using a Ge detector. The per-

∗1
∗2

124

Department of Analytical Biochemistry, Meiji Pharmaceutical University
Project Ward, National Cancer Center Hospital

centage of eﬄux of several metals, 59 Fe, 75 Se, 48 V, 65 Zn
and 74 As from PC-9/CPr were higher than those fromthe parental cell line PC-9. The eﬄux percentage proﬁle for Zn is shown in Fig. 1. We focused on the Zntransport system and performed RT-PCR analysis of
Zn transporters. Total RNAs were prepared from PC9 and PC-9/CPr cell lines. Reverse transcription and
PCR were performed as previously described.2) mRNAfor one Zn transporter was overexpressed in PC-9/CPrcells as compared with parental cells (Fig. 2).
From these results, one metal transporter gene,which was highly expressed in CPr cells, was identiﬁed by the MT technique.

Fig. 1. Eﬄux of Zn tracer in lung cancer cell lines.
Cisplatin-resistant cell line, PC-9/CPr (closed symbol)
and parental cell line, PC-9 (open symbol). 65 Zn wasmeasured using a Ge detector.

Fig. 2. mRNA expression of Zn transporter in PC-9/CPr
and PC-9.

References
1) T. Suzuki et al.: Curr. Drug Metab. 2, 363 (2001).
2) T. Suzuki et al.: J. Health Sci. 49, 524 (2003).

RIKEN Accel. Prog. Rep. 39 (2006)

Removal of radionuclides from solution by Escherichia coli
N. Ishii,∗ S. Uchida,∗ K. Tagami,∗ S. Enomoto, and H. Haba
Technetium-99 (99 Tc) is a radioactive contaminant
in marine1) and terrestrial environments.2) This radionuclide has a long half-life of 2.1 × 105 y, suggesting the accumulation of 99 Tc in the environment every year. In addition, technetium as pertechnetate(TcO4− ) is readily available to plants.3) It was ourconcern that 99 Tc may be transferred from plants tohumans. Therefore, the removal of 99 Tc from the environment is desirable.
The bacterium, Escherichia coli is able to remove99
Tc from solution under anaerobic conditions.4) Thisability of E. coli cells may also allow the removal ofother metal contaminants in the environment. In thisstudy, the removal of various radionuclides from solution by E. coli was investigated using a multitracer
technique.
A radioactive multitracer solution was obtained froma thin gold foil irradiated with a heavy ion beam of
135 MeV nucleon−1 in the RIKEN Ring Cyclotron.
Technetium, as NH499 TcO4, was obtained from Isotope Products Laboratories, Valencia, CA. Solutionsof a multitracer and 99 Tc were both sterilized bypassing them through a 0.2-µm-pore-size ﬁlter before
use. The ﬁlter-sterilized multitracer solution contained
83
Rb, 85 Sr, 88 Y, 139 Ce, 143 Pm, and 153 Gd.
E. coli HB101 (ATCC33694) was precultured in
LB medium at 37◦ C for 24 h. Cells were harvested,washed, and then suspended in a fresh LB medium.
The abundance of the cells was determined by measuring the turbidity of the suspension at an opticaldensity of 600 nm using a spectrophotometer UV-160(Shimadzu, Kyoto, Japan). The solutions of the multitracer and 99 Tc were separately added to the culture of
E. coli. The cultures with radioactive tracer elements
were incubated at 25◦ C in the dark under anaerobic
condition. For anaerobic incubation, a bag of Anaeropack Kenki (Mitsubishi Gas Chemical Co., Inc., Tokyo,
Japan) that absorbs oxygen and emits carbon dioxide
was used.
After the incubation, the culture was ﬁltered with a
0.2-µm-pore-size ﬁlter. The radioactivities of the multitracer in the culture and its ﬁltrate were measured
using a Ge detecting system (Seiko EG & G ORTEC).
The radioactivity of 99 Tc was measured with the TriCarb-25WTR Liquid Scintillation Analyzer (Packard,
IL, USA).
The removal of 99 Tc from solution by E. coli was observed (Fig. 1 (a)). The initial concentration of 99 Tc
was maintained for 1 d. This radionuclide was gradually removed from day 2 of incubation and then approximately 60% of the total 99 Tc added was removed∗

National Institute of Radiological Sciences

Fig. 1. Removal patterns of radionuclides from E. coli culture. The plots indicate the mean (n = 3).

on day 7 of incubation.
For radionuclides in the multitracer solution, twotypes of removal pattern were observed; these patterns
diﬀered from that of 99 Tc. As shown in Fig. 1 (b), 83 Rb
and 85 Sr were hardly removed during the experimental periods. On the other hand, 88 Y, 139 Ce, 143 Pm,
and 153 Gd were immediately removed from the solution (Fig. 1 (c)). From these results, it was found that
E. coli cells are able to remove the latter four radionuclides as well as 99 Tc from solution.
In the case of 99 Tc, E. coli removes it metabolically.4) but it seems that the removal mechanisms for88
Y, 139 Ce, 143 Pm, and 153 Gd are diﬀerent from thatfor 99 Tc. For instance, approximately 75% of total
143
Pm added was removed even on day 0 of incubation(Fig. 1 (c)), although the measurement of radioactivities on day 0 was carried out within 1 h from the addition of the multitracer solution. The rapid removalof 88 Y, 139 Ce, 143 Pm, and 153 Gd could be a result of
the electrochemical adsorption of these elements on thesurface of E. coli cells if those radionuclides are charged
positively, since the E. coli cell surface has a negative
charge. It is necessary to determine the chemical formsof those nuclides in the culture in the next step.
References
1) V. Smith et al.: J. Environ. Radioact. 56, 269 (2001).
2) K. Tagami and S. Uchida: J. Nucl. Radiochem. Sci. 3,
1 (2002).
3) R. E. Wildung et al.: Health Phys. 32, 314 (1977).
4) J. R. Lloyd et al.: J. Bacteriol. 179, 2014 (1997).

125

RIKEN Accel. Prog. Rep. 39 (2006)

Eﬀects of microorganisms on uptake of radionuclides by plants
T. Soshi,∗ I. Yamaguchi, and S. Enomoto
Radionuclides released by nuclear power plants into
the environment are a potential risk to human health.
Phytoremediation is an eﬃcient method of removing
radionuclides and other harmful pollutants from thesoil. We showed the eﬀects of microorganisms on the
uptake of radionuclides by host plants, such as perennial ryegrass for the endophyte Neotyphodium lolii, ricepathogenic fungus Gibberella fujikuroi. The Fusarium
species symbiotic to tomato was monitored using themultitracer technology. Figure 1 shows the uptake rateof several elements. In a noninfected tomato plant, theuptake rates of Na and Tc were high, about 10% for
Na and 32% for Tc. For other nuclides, such as Sc,
Mn, Co, Se, Rb, and Sr, the uptake rates were relatively low (1% to 8%). The uptake rates of Cs andZn were less than 1% (0.14% Cs and 0.77% Zn). The
perennial ryegrass colonized by the endophyte showeda lower uptake rate than the plant without the endophyte. G. fujikuroi was able to enhance the uptakeof radionuclides (Cs, Sr, Mn, Zn, and Co) by rice via
infection. The uptake rates of Mn and Co in an infected rice plant increased to almost as twice as thosein a noninfected rice plant. G. fujikuroi is known to
produce large amounts of gibberellins. The eﬀect ofgibberellin treatment on the radionuclide uptake byplants was almost the same eﬀect as infection of G.
fujikuroi. We also have analyzed the eﬀects of ﬁve
nonpathogenic strains, Fusarium oxysporum, Fusarium spio rycopersici isolated from tomato rhizosphere.
Each strain showed uptake enhancement of some radionuclides by plants. Finally, we indicated that theideal plant for phytoremediation should be fast growing, high in biomass, deep rooted, easy to harvest,
tolerant and able to accumulate metals in their aerial∗

126

Japan Environment Research Corporation

(a)

(b)
Fig. 1. Influence of endphyto on the uptake of radionuclides
by perennial rygrass. (a) uptake of Sc, Mn, Co, Zn,
Se, Rb, Sr, Cs. (b) uptake of Na and Tc by perennial
rygrass. Data was expressed as the uptake percentage
compared to the control per gram dry weight of theplant. Error bar shows standard deviation.

part. However, no plant that fulﬁlls all those criteria
has been described. In terms of phytoremediation ofcontaminated soil using long-lived radionuclides suchas Sr and Cs, the use of a rhizofungus that can enhance
the uptake of radionuclides by plants is expected to increase the clean-up eﬃciency markedly.

RIKEN Accel. Prog. Rep. 39 (2006)

Imaging performance test of prototype model for GREI
S. Motomura, S. Enomoto, H. Haba, Y. Gono, and Y. Yano
We are developing a γ-ray emission imaging (GREI)
apparatus that enables simultaneous and nondestructive imaging of multitracer distribution.1) The current
prototype model is a Compton camera consisting of
two double-sided orthogonal-strip germanium (Ge) detectors. To reconstruct the distribution image, a simple back-projection (SBP) image is constructed ﬁrst
from the obtained data, then the SBP image is processed with analytical or iterative reconstruction methods.2)
The quality of the image is aﬀected by the statistics, that is, how many data are obtained for the γrays speciﬁc for the nuclide. We have already estimated the relationship between the spatial resolution
and the statistical noise components in the SBP image
by Monte Carlo simulation.3) In this report, we willshow an experimental result that shows the imaging
performance of the current prototype model.
The γ-ray measurement was performed under thesame condition as the simulation. A pointlike γray source of 65 Zn, which emits 1116 keV γ-rays, wasplaced 69 mm apart from the center of the front Ge detector. The measurement was continued until 1.0×105
events were collected. After the measurement, SBP
images were constructed from the stored data with
1.0 × 104 , 5.0 × 104 and 1.0 × 105 events.
Figure 1 shows the Fourier power spectral densities (FPSDs) of the SBP images obtained in the experiment. One can see in Fig. 1 that the statisticalnoise dominates the high-frequency components because they are signiﬁcantly dependent on the statistics.
The reconstructed images with 1.0 × 104 and 1.0 × 105
events are shown in Fig. 2. A higher spatial resolution
was obtained when the number of events was larger.
The relationship between the full width at half maximum (FWHM) of the reconstructed image and (2fc )−1
is shown in Fig. 3, where fc is the spatial frequency
that the noise components are beginning to dominate
in the FPSD of the SBP image. Figure 3 seems to

Fig. 2. Reconstructed image of point source with 1.0 × 104
and 1.0 × 105 events.

Fig. 3. Relationship between spatial resolution and statistical noise component. The definition of fc is given in
the text.

show that the spatial resolution has the same valueas (2fc )−1 . These results are in good agreement withthose of the simulation.
When we design detectors for use with the apparatus, the imaging performance should be optimized considering the required measurement time and the spatial
resolution. However, the image reconstruction method
suitable for the apparatus has not been completed yet.
In spite of this, we can carry out the optimization of theperformance because we have obtained the relationshipbetween the spatial resolution and the statistical noise
components in the SBP image.
References

Fig. 1. Fourier power spectral densities of SBP images obtained by experiment.

1) S. Motomura and S. Enomoto: J. Clin. Exper. Med.
205, 884 (2003).
2) S. Motomura et al.: RIKEN Accel. Prog. Rep. 38, 124(2005).
3) S. Motomura et al.: RIKEN Accel. Prog. Rep. 38, 125(2005).

127

RIKEN Accel. Prog. Rep. 39 (2006)

Reactions of 57 Mn implanted into solid oxygen
Y. Kobayashi, H. Nonaka,∗1 J. Miyazaki,∗1 K. M. Kubo,∗2 H. Ueno, A. Yoshimi, H. Miyoshi,∗3 D. Kameda,
K. Shimada,∗3 D. Nagae,∗3 K. Asahi, and Y. Yamada∗1
We have studied novel chemical reactions of 57 Mn
atoms with oxygen by in-beam Mössbauer spectroscopy using a short-lived radioactive beam, 57 Mn(T1/2 = 1.45 min). Implantation of particles directly
into an appropriate substance produces a variety ofnovel chemical species and exotic valence states unavailable under normal conditions. In our previous
study, a high valence state of Fe(VIII) was obtained
from the in-beam Mössbauer spectra of 57 Fe/57 Mn implanted into KMnO4 at low temperatures.1) In thisstudy, we report the in situ characterization of the reaction products between Fe and oxygen by 57 Fe/57 Mn
implantation Mössbauer spectroscopy. The oxidationof Fe is a fundamentally interesting subject from theviewpoint of the corrosion of materials and catalytic
reactions.
57
Mn particles were produced as a secondary RI
beam following a nuclear projectile fragmentation of
58
Fe21+ beams (E = 63 MeV/nucleon, I = 40 pnA)
accelerated by a linac and a ring cyclotron with a Be
production target. The 57 Mn was separated and focused by the in-flight isotope separator using RIPS.
Subsequently, the 57 Mn was implanted into a solid O2
sample after passing through an Al plate with an appropriate thickness to suppress the beam energy down
to about 26 MeV/nucleon. The stopping range of 57 Mn
in the solid O2 was calculated to be 180 µm from thesurface with the straggling range of ±100 µm. The
beam intensity of 57 Mn was typically 5 × 106 particles/s.
The solid O2 sample was prepared on an Al plate(18 K). The thickness of the sample was estimated tobe approximately 1 mm. The 14.4 keV γ-rays emitted
from 57 Mn were detected by a parallel-plate avalanche
counter (PPAC) with an 57 Fe-enriched stainless-steel
foil.
Solid O2 appears in α- (0 ≤ T ≤ 24 K), β- (24 ≤ T ≤44 K), and γ-phases (44 ≤ T ≤ 54 K). The 57 Fe/57 Mn
in-beam Mössbauer spectra were measured at 18, 32
and 40 K during the implantation of 57 Mn. The counting times were 18, 12, and 12 hr, respectively. The total implantation dose of 57 Mn was typically 5 × 1011
57
Mn/cm2 for one spectrum. The spectra obtained at
18 and 32 K are shown in Fig. 1 (a) and (b), respectively. The spectra obtained at 32 and 40 K have twocomponents of Fe in the Al substance, which were asubstitutional Fe atom (I.S. = −0.56 mm/s at 30 K)
and an interstitial one (I.S. = −0.19 mm/s at 30 K);
∗1
∗2
∗3

128

Department of Chemistry, Tokyo University of Science
College of Liberal Arts, International Christian University
Department of Physics, Tokyo Institute of Technology

Fig. 1. In-beam Mössbauer spectra of 57 Fe/57 Mn atoms
implanted into solid oxygen at (a) 18 and (b) 32 K.

some of 57 Mn particles reached the Al substance when
the thickness of solid oxygen became smaller as the O2
molecules evaporated due to the higher vapor pressure
at higher temperatures.
Our present results of in-beam Mössbauer spectra
proved to have 4 components of Lorentzian doublets.
These components were assigned to FeO (S = 2),
Fe(O2 ) (S = 1), (O2 )FeO2 (S = 0), and Fe(O2 )2 (S =0) from the Mössbauer parameters (I.S. and Q.S.).
The assignments were confirmed by ab-initio molecular orbital calculations using Gaussian 98 and 03 programs. While FeO, Fe(O2 ), and (O2 )FeO2 were also
produced by the reaction of the laser-evaporated Fe
atoms with O2 ,2) divalent Fe(O2 )2 was newly formed inthis 57 Mn implantation experiment. Fe(O2 )2 is a major component of resonance areas (49% at 18 K, 45%
at 32 K) in the spectra (Fig. 1). Although an energetic
57
Mn atom certainly creates defects and decomposes
the O2 molecules until it stops at the suitable final
position in solid O2 , the 57 Fe atom at the final position is neatly surrounded by O2 molecules. Therefore,
Fe(O2 )2 is obtained as the primary 57 Fe product, which
has O2 without breaking O-O bond.
References
1) Y. Kobayashi, M. K. Kubo, Y. Yamada, T. Saito, H.
Ueno, H. Ogawa, W. Sato, K. Yoneda, H. Watanabe,
N. Imai, H. Miyoshi, and K. Asahi: J. Radioanal. Nucl.
Chem. 255, 403 (2003).
2) Y. Yamada, H. Sumino, Y. Okamura, H. Shimasaki, andT. Tominaga: Appl. Radiat. Isot., 52, 157 (2000).

RIKEN Accel. Prog. Rep. 39 (2006)

Production of 83 Rb for 83 Kr Mössbauer spectroscopy
K. M. Kubo,∗1 Y. Kobayashi, Y. Yamada,∗2 and H. Haba
Krypton is one of the rare gas (RG) elements. After
xenon was found to form fluorides and is not truly inert
to chemical reaction, the first krypton compound KrF2
was synthesized in 1963.1) Since then there have been
numerous studies on the synthesis of RG compounds
and clarification of the nature of their chemical bonds.
On the basis of ab initio molecular orbital calculations, the nonfluorinated compound HKrCl was prepared in 1995.2) There have been few attempts to prepare novel RG compounds containing RG-C bonds.3)
In these attempts, the matrix-isolation-laser-excitation(MILE) technique was adopted. A reactant compound,e.g., hydrogen chloride is condensed onto a CsI substrate with a RG to form a reaction matrix. After condensation, the matrix is irradiated with a laser beam
to excite the reactant to form a RG compound. RG
compounds formed are confirmed by IR spectroscopy.
In MILE experiments there is a limitation that one
RG atom can form a chemical bond to only one reactant molecule, because the reactant concentration is
kept low (molar ratio of RG/reactant ≥ 1000). Compounds with xenon and acetylene were prepared in
2003.4) Krypton compounds with a similar structure
are believed to exist on the basis of calculations, buthave not been experimentally confirmed.
We have been applying an ion implantation method
to generate novel and rare chemical compounds of
Fe using the RIKEN cyclotron in combination withemission Mössbauer spectroscopy as a characterization
method.5) By this method, we prepare various solid
targets to react with incoming ions. We may observe
the reactions of krypton with various solid materials
using the RIKEN cyclotron.
Fortunately, krypton has the Mössbauer active nuclide 83 Kr. Mössbauer spectroscopy provides information on the valence state and electric field gradientat the Kr nucleus, complementary to IR spectroscopy,
which provides atom-atom bond parameters. With theaim of producing compounds consisting of one krypton and two or more reactant molecules beyond thescope of the dilute MILE condition, we have started a
new project on 83 Kr Mössbauer spectroscopy using the
RIKEN cyclotron. As the first, step we are setting up aMössbauer spectrometer for 83 Kr using a radioisotope∗1∗2source, 83 Rb (T1/2 = 86.2 d).
The Mössbauer level of 83 Kr is the first excited state
at 9.396 keV. Above this level there is a metastablestate, 83m Kr, with a half-life of 1.83 h. There have been
83
Kr Mössbauer studies since the 1960’s. Most of theprevious studies used 83 Rb as the radiation source embedded in solid matrices. We chose a 83m Kr source separated from 83 Rb to reduce the radiation backgroundfrom 83 Rb. Carrier-free 83m Kr deposited on a coldplate will enable us to obtain Mössbauer spectra ofgood quality.
A CaBr2 target was irradiated with an α particle
beam of 25 MeV. After the irradiation, the target wasdissolved in water. (NH4 )CO3 solution was added toprecipitate and separate CaCO3 . For the isolation of83
Rb, 18-crown-6 and picric acid were added to thesolution and extracted with chloroform.6) With a 2 gmolecular sieve, the chloroform solution was evaporated. The molecular sieve containing 83 Rb was packed
in a glass tube and placed in a gas line. Helium gas was
passed through the gas line and the cold trapping of
83m
Kr generated from the 83 Rb in the molecular sieve
was attempted. Measurements using a proportionalcounter showed no evidence of trapping of 83m Kr. It
was supposed that picric acid covered the surface of themolecular sieve and prevented 83m Kr to escape fromthe molecular sieve. We are now planning to change
the separation method using an ion-exchange resin instead of carrying out crown ether extraction.
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. Kobayashi et al.: RIKEN Accel. Prog.
Rep. 38, 111 (2005).
6) T. Kimura et al.: Chem. Lett. 1977, 563.

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

129

RIKEN Accel. Prog. Rep. 39 (2006)

99

Ru Mössbauer and µSR studies of CaRuO3

Y. Kobayashi, T. Taniguchi,∗ I. Watanabe, T. Suzuki, S. Mizusaki,∗ H. Haba, T. Okada,
Y. Noro,∗ and Y. Nagata∗
A series of ternary Ru oxides, M RuO3 (M = alkali earth metals), have been known to show a wide
variety of magnetic properties, where the electron conﬁguration of Ru ions is 4d4 in the low-spin state (S =1). Although both CaRuO3 and SrRuO3 have similar
distorted cubic perovskite structures, their magnetic
properties are very diﬀerent. Static magnetic measurement, neutron diﬀraction, and Mössbauer studies
well established that SrRuO3 becomes ferromagnetic
below Tc = 165 K. However, the magnetic propertiesof CaRuO3 at low temperatures are not yet thoroughly
understood, as compared with those of SrRuO3 . Recent literature contains contradictory results, for example, CaRuO3 is antiferromagnetic, Pauli paramagnetic, exchange-enhanced paramagnetic, weakly ferromagnetic, or in a spin-glass state with long-range ordering. The unconﬁrmed trigger for the magnetic behavior of CaRuO3 , as described above, is that the electronic states of the Ru oxides are very sensitive to theexistence of disorder and defects around Ru ions.
In this study, we have applied 99 Ru Mössbauer spectroscopy and µSR measurement to a single crystal of
CaRuO3 to clarify the magnetic ground state of thissample.
Single crystals of CaRuO3 were prepared by the ﬂux
method with powdered polycrystalline samples as thestarting material. A polycrystalline CaRuO3 sample
was obtained by sintering a stoichiometric compositionof RuO2 and CaCO3 at 1200◦ C for 48 h. Then, a mixture of a polycrystalline CaRuO3 and a ﬂux of CaCl2
was heated at 1300◦ C for 5 h and cooled to 1100◦ C by
the slow rate of 1◦ C/h. The single crystals of CaRuO3
could be collected by washing out the ﬂux. The chemical composition, the X-ray diﬀraction pattern, themagnetization, and the electrical resistivity were measured. The temperature dependence of the magnetic
susceptibility of CaRuO3 follows the Curie-Weiss law
in the high-temperature region above about 50 K, but
gradually deviates from the law upon lowering the temperature to 1.7 K. The eﬀective paramagnetic moment(peﬀ ) and the paramagnetic Curie temperature (Θ) are
2.82 µB and −200 K, respectively. The detailed characterizations of polycrystalline and single-crystalline
CaRuO3 have been described in Refs. 1 and 2.
The 99 Ru Mössbauer spectra were measured at 5
and 1.6 K, as shown in Figs. 1 (a) and (b), respectively.
The Mössbauer source nuclide 99 Rh (T1/2 = 15.0 d)
was prepared by proton irradiation of a 95%-enriched99
Ru metal target in the AVF Cyclotron.3) The spectra∗

130Colledge of Science and Engineering, Aoyama Gakuin University

Fig. 1. 99 Ru Mössbauer spectra of CaRuO3 at (a) 5 K and(b) 1.6 K.

down to 5 K apparently consist of small doublets withslight asymmetry, as typically observed for an electric
quadrupole interaction with no appreciable hyperﬁnemagnetic interaction, and were analyzed satisfactorily
under the assumption of a pure electric ﬁeld gradientwith axial symmetry. The derived isomer shift andquadrupole splitting are −0.31 mm/s and 0.22 mm/s,
respectively. Our Mössbauer results for CaRuO3 down
to 1.6 K are consistent with the absence of an anomaly
in the magnetization measurement.
The µSR measurement was carried out at the
RIKEN-RAL Muon Facility in the UK, using a pulsed
muon beam and a 3 He cryostat down to 0.3 K. The ZFµSR time spectrum (Fig. 2) can be well analyzed using
an exponential function, suggesting the existence of dynamically ﬂuctuating internal ﬁelds at the muon site.
The time spectrum was decoupled by the application ofan external ﬁeld of 100 G, proving that the muon spin
depolarized mainly due to nuclear dipole ﬁelds from
Ru. From these results, we conclude that the electronic moments of Ru are in the paramagnetic state
and are still dynamically ﬂuctuating at 0.3 K. Thus,on the basis of our results of the 99 Ru Mössbauer andµSR studies, it is concluded that CaRuO3 has no appreciable magnetic ordered state down to 0.3 K.

Fig. 2. µSR time spectra of CaRuO3 at 0.3 K.

References
1) A. Koriyama et al.: J. Alloys Compd. 171, 339 (2003).
2) A. Koriyama et al.: J. Alloys Compd. 372, 58 (2004).
3) Y. Kobayashi et al.: Inorg. Chem. 31, 4570 (1992).

RIKEN Accel. Prog. Rep. 39 (2006)

Eﬀect of heavy-ion-induced DNA damage on response of
DNA-dependent protein kinase
M. Tomita,∗ M. Izumi, T. Tsukada, N. Fukunishi, H. Ryuto, Y. Yano, and K. Sakai∗
Ionizing radiations induce DNA double-strand
breaks (DSBs). In vertebrate cells, there are two major DSB repair pathways: non-homologous end joining (NHEJ) and homologous recombination (HR).1)
The repair of DSBs by NHEJ requires at least DNAdependent protein kinase (DNA-PK), XRCC4 andDNA ligase IV. DNA-PK is composed of a catalytic
subunit (DNA-PKcs) and DNA end-binding Ku70 and
Ku86 heterodimer. DNA-PK is activated to bind to
the ends of double-stranded DNA, and phosphorylates
XRCC4.2,3)
Accelerated heavy ions with high linear energy
transfer (LET) can induce complex clustered DNA
damage involving two or more DSBs. The complexityof clustered DNA damage shows a strong LET dependence, which makes it a good candidate prime determinant of the higher biological eﬀectiveness of highLET heavy ions than that of low-LET X-rays.4) We
previously reported that DNA-PKcs phosphorylatedon Thr2638 is recruited in the vicinity of clustered
DNA damage induced by heavy ions.5) In addition, therelative biological eﬀectiveness (RBE) for cell killingin DNA-PKcs-defective human M059J cells is significantly lower than that in normal M059K cells.6) To
further analyze the response of DSB repair proteinsto heavy-ion-induced DSBs in vertebrate cells, we are
currently investigating the sensitivity to heavy ions ofmutants defective in DSB repair genes generated fromthe chicken B-cell line DT40. Here, we show the sensitivity of DNA-PKcs−/−/−7) cells to high-LET Ar
ions.
Figure 1 shows the clonogenic surviving fractionsof wild-type and DNA-PKcs−/−/− DT40 cells irradiated with 250 kV X-rays or 95 MeV/u Ar ions at
350 keV/µm. The surviving fractions were determinedby a colony formation assay. The radiosensitivity of
wild-type DT40 cells to Ar ions was higher than thatto X-rays (Fig. 1 (A)). The dose leading to 10% cell
survival ( D10 ), calculated from the cell survival curve,
was 4.9 Gy and 2.8 Gy for X-rays and Ar ions, respectively (Table 1). The RBE relative to X-rays was
1.8. On the other hand, the radiosensitivity of DNAPKcs−/−/− cells to Ar ions was not largely diﬀerent
from that to X-rays (Fig. 1 (B)), although the cell survival curve for X-rays was biphasic. The D10 values
were 2.8 Gy and 2.5 Gy for X-rays and Ar ions, respectively. Thus, the RBE in DNA-PKcs−/−/− cells was
1.1, which is signiﬁcantly lower than that in wild-type
cells (Table 1). Our present and previous results5,6)
suggest that NHEJ cannot eﬃciently repair DSBs in∗

Fig. 1. Cell survival curves for wild-type (A) and DNAPKcs−/−/− (B) DT40 cells. Cells were irradiated with
250 kV X-rays and 95 MeV/u Ar ions (350 keV/µm).
Error bars represent standard errors of means (SEM),
which were obtained from two to five independent experiments.

Table 1. D10 and RBE values.
D10 a (Gy)
X-rays Ar ions
Wild
4.9
2.8
DNA-PKcs−/−/−
2.8
2.5
a
The dose leading to 10% cell survival.
Cells

RBE
1.8
1.1

duced by high-LET heavy ions.
References
1) K. K. Khanna and S. P. Jackson: Nat. Genet. 27, 247(2001).
2) G. C. M. Smith and S. P. Jackson: Genes Dev. 13, 916(1999).
3) Y. Matsumoto et al.: FEBS Lett. 478, 67 (2000).
4) D. T. Goodhead: J. Radiat. Res. 40, Suppl. 1 (1998).
5) M. Tomita et al.: RIKEN Accel. Prog. Rep. 38, 129(2005).
6) M. Tomita et al.: RIKEN Accel. Prog. Rep. 37, 145(2004).
7) T. Fukushima et al.: J. Biol. Chem. 276, 44413 (2001).

Central Research Institute of Electric Power Industry

131

RIKEN Accel. Prog. Rep. 39 (2006)

Maximal protection by DMSO in inactivation of mammalian cells
exposed to very high LET radiation
R. Hirayama,∗1,∗2 A. Ito,∗3 Y. Furusawa,∗2 M. Tomita,∗4 T. Tsukada, M. Izumi, F. Yatagai, and K. Ando∗2
Interactions between ionizing radiation and biological targets include direct action and indirect action.
It has been well known that indirect action is important in the case of low linear energy transfer (LET)
radiation including X-rays and γ rays. Chapman et al.
reported that the extent of protection by 2 M DMSO
against carbon ions with an LET of 180 keV/µm is atleast 50% for cell inactivation.1) Roots et al. used 1.5–
2 M ethylene glycol as an OH radical scavenger in Chinese hamster ovary cell inactivation by very high LET
radiation.2) They estimated indirect action of approximately 20–25% at LETs higher than 600 keV/µm. Itoet al.3) estimated the maximal contribution of indirect
action up to an LET of 440 keV/µm using a method
proposed by Shinohara et al.4) in which protection levelis extrapolated to an inﬁnite DMSO concentration. In
this study, we have extended the estimation of a maximal protectable fraction by DMSO to a very high LET
region of up to 2000 keV/µm. The protectable fraction
was estimated from the regression curves for reciprocalplots of DMSO concentration versus degree of protection that was obtained using

Fig. 1. Panel A: Survival data for V79 cells irradiated withiron ions in presence of various DMSO concentrations.
Panel B: The degree of protection was estimated using
Eq. (1). Panel C: Reciprocal plots for results shown inpanel B.

39 and 32% at LETs of 797, 1298 and 2106 keV/µm,
respectively (Fig. 2). We propose the importance ofthe contribution of indirect action to cell death evenat very high LETs.

Degree of protection = (ln SF0 − ln SFx )/ln SF0 (1)where SF0 and SFx are surviving fractions at 0 M andx M DMSO. The formula was calculated from thereciprocal of DMSO concentrationy = k · (1/x) + y∞(2)

where y is a reciprocal of the degree of protection by
DMSO and y∞ is a reciprocal of the degree of protection by DMSO at ultimate concentration. Slope k is
an inclination of the regression line.
Indirect action (%) = (1/y∞ ) × 100(3)

We have examined the radioprotection eﬀects of various DMSO concentrations on Chinese hamster V79
cells irradiated with iron ions (Fig. 1). DMSO seems
to have little toxicity, because plating eﬃciency washigh (0.83) in the presence of 1.0 M DMSO. The contribution of indirect action decreased with increasing
LET, and became constant at very high LETs. The
contributions of indirect action to cell death were 52,
∗1
∗2
∗3
∗4

132

Graduate School of Science and Technology, Chiba University
Heavy-ion Radiobiology Research Group, National Instituteof Radiological Sciences
Course of Energy Engineering, Department of Applied Science, School of Engineering, Tokai University
Low Dose Radiation Research Center, Nuclear Technology
Research Laboratory, Central Research Institute of ElectricPower Industry

Fig. 2. LET dependence of indirect action (maximal protectable fraction by DMSO) on death of V79 cells. The
error bars are SEM for a protectable fraction calculated
from a regression line that was drawn for nine or twelve
diﬀerent points.

References
1) J. D. Chapman et al.: Radiat. Environ. Biophys. 16, 29(1979).
2) R. Roots et al.: Int. J. Radiat. Biol. Relat. Stud. Phys.
Chem. Med. 47, 157 (1985).
3) A. Ito et al.: Radiat. Res., in press.
4) K. Shinohara et al.: Acta Oncol. 35, 869 (1996).

RIKEN Accel. Prog. Rep. 39 (2006)

Mutation induction in frozen human cultured cells by low-dosecarbon ion irradiation
Y. Umebayashi, M. Honma,∗ T. Abe, M. Iwaki, and F. Yatagai
It is important to elucidate the genetic inﬂuences of
low-dose or low-dose rate ionizing radiation at the cellular level. For the convenience of molecular analysis ofmutations located in the gene as well as those extending to the chromosome, we have developed a methodology (Fig. 1) using human lymphoblastoid cell TK6
and succeeded in detecting low-dose carbon ion beamirradiation eﬀects.1) Our interest extends to whether
we can detect such radiation eﬀects in TK6 after theirradiation of frozen cells. The success of our attempt
is reported here.
TK6 cells are functionally heterozygous at their TK
locus. TK6 cells were treated with HAT medium toeliminate pre-existing TK− mutants and then frozen
and kept in a −80◦ C freezer. Then, the frozen cells
were exposed to 10 cGy of C-ion (135 MeV/u) accelerated by RIKEN Ring Cyclotron, while cooling it withdry ice and ethanol. Then the cells were preservedin a −80◦ C freezer until the assays. TK− mutant
clones were isolated on the basis of their resistanceto 4 µg/ml triﬂuorothymidine (TFT). The early TK−
mutant clones (EM) and the late ones (LM) were selected after two and four weeks of incubation, respectively (Fig. 1). The selected TK− mutants were ﬁrst
analyzed in determining the loss of TK heterozygosity (LOH) by the PCR analysis of the exons 4 and 7
regions in the TK locus. This PCR analysis also provided us the types of LOH, hemizygous and homozygous, considered as a result of the end-joining repair
or homologous recombination repair of DNA doublestrand breaks (DSBs), respectively. To determine theextension of deleted or replaced parts of the chromosome in the LOH mutants, we analyzed 10 microsatellites on chromosome 17 by multiple PCR.
Figure 2 shows the average values of plating eﬃciency (PE) and TK− mutation frequency (MF) of
more than three independent experiments. These mea-

Fig. 1. Schematic illustration of experimental procedures.
∗

Division of Genetics and Mutagenesis, National Institute of
Health Sciences

Fig. 2. Plating eﬃciency (PE) and TK mutation frequency(MF).

surements demonstrated that this level of low-dose irradiation of frozen cells is not toxic for cell viability.
No toxic eﬀects were observed after the C-ion irradiation with the same dose under normal incubation of thesuspension culture. In both assays performed within a
few days and after about one month, total TK− MFs(EM + LM) were increased by the 10 cGy C-ion irradiation to about 1.6-fold (2.5 × 10−6 to 3.9 × 10−6 ) and
2.1-fold (2.5 × 10−6 to 5.3 × 10−6 ), respectively. Suchincreases were statistically signiﬁcant not in the caseof a few days but in the case of one month.
The PCR analysis of TK− mutants showed no speciﬁc changes in the distribution of mutation classes(non-LOH, hemizygous LOH, and homozygous LOH)
by the 10 cGy C-ion irradiation (data, not shown).
However, the following characteristic changes in theﬁne structure of LOHs were observed after this lowdose irradiation level. As observed in the suspension
culture irradiation,1,2) the special type of hemizygous
LOH events, in which the deleted part of the chromosome does not reach the telomere marker, wereidentiﬁed only in the irradiation case. This LOH
events can be suggested to reﬂect the eﬀect of C-ion
irradiation, because DSBs created by C-ion traversal
through the cell result in this special type of hemizygous event through the nonhomologous end-joining repair of DSBs.
The present results suggest that this mutational
analysis can be used for estimating the genetic effects of low-dose ionizing radiation, particularly heavyions. These results could also provide the possibilityof obtaining information about the genetic inﬂuencesof space environmental radiation using this frozencell system in our future experiments at International
Space Station.
References
1) S. Morimoto et al.: J. Radiat. Res. 43, 163 (2002).
2) S. Morimoto et al.: Radiat. Res. 157, 533 (2002).

133

RIKEN Accel. Prog. Rep. 39 (2006)

Study on mutants of Monascus pilosus induced by heavy-ion beam
T. Koide,∗1 H. Saito, Y. Miyazawa,∗2 T. Abe, H. Ryuto, and N. Fukunishi
A heavy-ion beam is available for breeding technology and much data has been accumulated, particularly regarding plants.1) However, there is no reportabout the eﬀect of heavy-ion beams in ﬁlamentous
fungi. Monascus, a traditional fermentation fungus, isused as a natural dietary supplement. In this report,
Monascus pilosus IFO 4520 was exposed to various
types of heavy-ion.
The conidia of M. pilosus for irradiation were prepared as follows. M. pilosus were cultured on PDA
medium for 1 week, and the myceria were suspended
in distilled water. The suspension was ﬁltered using
cotton to remove the myceria and the ﬁltrate including
conidia was obtained. The ﬁltrate was irradiated with12
C, 20 Ne and 40 Ar ions in dose ranges of 50 to 300 Gy,
10 to 200 Gy, and 5 to 100 Gy, respectively. These ionswere accelerated up to 135, 135 and 95 MeV/nucleon,
and their LETs were approximately 22.5, 61.0 and
281.5 keV/µm, respectively.
After the irradiation, the ﬁltrates were spread on
PDA medium. Survival rates were determined on thebasis of colony-forming ability (Fig. 1). The lethal dose
50 (LD50 ) was estimated from dose-response curves
and the relationship between LD50 and LET is shownin Fig. 2. All of the dose-response curves are of thesigmoidal type. The 20 Ne- and 40 Ar-ion beams hadgreater lethal eﬀects than the 12 C-ion beam, and thisdiﬀerence is thought to be due to LET. It is impossible to explain the relationship between the lethal effect and LET is impossible since there are few data in
Fig. 2. Further investigation is required to reveal that
LET has an optimum value or ﬂattens over some value.

∗1
∗2

134

Riken Vitamin Co., Ltd.
Graduate School of Life Sciences, Tohoku University

Fig. 1. Dose-response curves of conidia of M. pilosus IFO
4520 exposed to 12 C (circle), 20 Ne (square) and 40 Ar(triangle) ion beams.

Fig. 2. Relationship between LD50 and LET.

Reference
1) H. Saito et al.: RIKEN Accel. Prog. Rep. 37, 147(2004).

RIKEN Accel. Prog. Rep. 39 (2006)

In situ visible markers of Arabidopsis for radiation biology
Y. Y. Yamamoto, M. Saito,∗ S. Yoshida, and T. Abe
In this study, two molecular markers were used for insitu detection of genetic alterations. The two detection
markers were applied to heavy-ion biology for the ﬁrst
time.
The ﬁrst marker is for the detection of mutation at
the mutated generation (M1 ). Because of the diploidnature of higher plants, a genetic mutation is not detected as a phenotypic alteration until homozygous
mutants are identiﬁed at the next generation after mutagenesis (= M2 ). However, we considered it would bepossible to detect mutations at M1 , if we focus on a
speciﬁc locus.
The Arabidopsis COP9 gene suppresses anthocyanin
biosynthesis, and the loss of COP9 results in aheavy accumulation of anthocyanins, which are red
pigments.1) A null allele of COP9, obtained by theinsertion of a kanamycin-resistant gene,1) enables the
preparation of its heterozygous seedlings (COP9 +/− ).
Grown on a kanamycin-containing medium, wild-typeseedlings have kanamycin-sensitive white cotyledons,
and heterozygotes have kanamycin-resistant green
cotyledons. The homozygote (COP9 −/− ) plants arealso resistant to kanamycin, but have red cotyledons
due to the loss of COP9. If the intact allele of the heterozygote is damaged by mutagens, the aﬀected cell is
expected to show red pigmentation. Because diﬀerent
cells undergo diﬀerent mutations by mutagenic treatments, a mutagenized M1 plant is expected to show achimeric feature.
The seeds of cop9 heterozygotes obtained by
self-pollination, which are a mixture of segregated
COP9 +/+ , COP9 +/− , and COP9 −/− seeds, were irradiated with a Ne-ion beam. The treated seeds weregrown on a medium containing kanamycin, and heterozygote seedlings were selected and grown in soil.
About one month after the transfer, the plants were
examined for the presence of red cells. As expected,
clear red sectors were observed (Fig. 1). Such sectors
were not observed among nonirradiated populations ofcop9 heterozygotes (Table 1) or irradiated wild-type
populations (data not shown), strongly suggesting thatthe sectors are caused by the mutation of COP9. Our
results demonstrate that mutation rate can be monitored at M1 generation using this “red sector” assay.
In addition, this assay might be useful for the analysis of cell lineage, because one continuous sector isthe oﬀspring of a single cell at the time of mutagenic
treatments.
We also attempted to examine the COP1 locus2)
using the same assay, but we could not observe any
clear red sectors after Ne-ion beam irradiation (data∗

Fukui Agricultural Experiment Station

Fig. 1. Red sector on cop9 heterozygote plant found in
population of Ne-ion-beam irradiated plants. The arrow indicates the sector.
Table 1. cop9 sectors observed on heterozygote plants.

not shown).
The second marker is for the in situ detection of homologous recombination (HR). Swoboda et al. havedeveloped an assay system in which the recombinationof neighboring homologous regions results in the recovery of the split GUS gene, and the event is detectedby GUS staining.3) Using this assay, their group foundthat the irradiation with γ ray and UV enhances HR
activity.4,5) Our question is whether HR is also stimulated by irradiation with a heavy-ion beam. Dry seeds
carrying the split GUS reporter were irradiated with
the Ne beam, germinated and grown for two weeks.
The seedlings were then subjected to in situ GUS
staining, and blue areas indicating GUS activity werecounted. As shown in Table 2, HR frequency increased
threefold following the irradiation. We observed thatthe blue staining did not form long sectors as shown in
Fig. 1, but a spotty staining pattern was observed intissues that developed after germination, such as thestems and true leaves (data not shown). This observed
staining pattern indicates that the stimulation of HR
lasts for weeks after the irradiation and the response
is systemic.
In summary, our two assays using two visible markers as described above showed reasonable responses
to Ne beam irradiations, demonstrating that they areboth useful for studies in radiation biology.
Table 2. In situ detection of HR by split GUS.

References
1) N. Wei et al.: Cell 78, 117 (1994).
2) X.-W. Deng et al.: Cell 71, 791 (1992).
3) P. Swoboda et al.: EMBO J. 13, 484 (1994).
4) G. Ries et al.: Nature 406, 98 (2000).
5) O. Kovalchuk et al.: Mutat. Res. 449, 47 (2000).

135RIKEN Accel. Prog. Rep. 39 (2006)

Einkorn wheat mutant, mvp which shows maintained vegetative
phase is caused by ion-beam-derived mutation of wheat APETALA1
K. Murai,∗ C. Ikari,∗ N. Shitsukawa,∗ S. Shimada,∗ K. Sakamoto, H. Saito, H. Ryuto, N. Fukunishi, and T. Abe
The timing of the phase transition from vegetative
to reproductive growth is related to heading time,
which is one of the most important traits in cereal
crops. In wheat, heading time is genetically determined by three component characteristics, i.e., vernalization requirement, photoperiodic sensitivity andnarrow-sense earliness (earliness per se) that is, theautonomous promoting pathway.1) Vernalization requirement means the sensitivity of the plants to cold
temperature which accelerates spike primordium formation; vernalization-insensitive (spring habit) genes,
Vrn-A1, Vrn-B1 and Vrn-D1, were genetically identified on chromosomes 5A, 5B and 5D, respectively.
The photoperiodic (long-day) response is controlled bythree genes, Ppd-A1, Ppd-B1 and Ppd-D1, located on
chromosomes 2A, 2B and 2D, respectively. Narrowsense earliness is the earliness of fully vernalized plants
grown under long-day conditions, and no major genes
have been detected for this character. In Arabidopsis, a MADS-box gene, APETALA1, functions in floral meristem formation as well as floral organ formation, and plays an important role in phase transition.2)
In the previous research, we revealed that the wheat
APETALA1 ortholog, WAP1 (Wheat AP ETALA1 ),is a key gene in the regulatory pathway controlling
the phase transition from vegetative to reproductive
growth in wheat, and WAP1 is identical to Vrn genes
for vernalization insensitiveness, which have been genetically identified.3) Here, we report an einkorn wheat
mutant showing a maintained vegetative phase (mvp)
phenotype after ion-beam treatment, which does nottransit from the vegetative to reproductive phase. The
mvp mutant was caused by the deletion of WAP1 coding and promoter regions, which indicates that WAP1
is an indispensable gene for phase transition in wheat.
Einkorn wheat (Triticum monococcum) strains
KU104-1 and KU104-2 were used for ion-beam (N,
50 Gy) treatment. We obtained two alleles of mvp mutation, one from 1326 M2 lines of KU104-1 and theother from 1921 M2 lines of KU104-2, mvp2 and mvp1,
respectively (Fig. 1). M3 lines, segregating mvp andwild-type (WT) phenotypes, were planted in the field
and their phenotypes were analyzed. To confirm thatthe mvp phenotype is caused by the deletion of WAP1,
we performed PCR analysis of individual M3 plants.
Genomic DNA was isolated from each M3 plant, andthe presence or absence of the WAP1 gene was assessed using WAP1 -specific primer. As a result, theWAP1 -deleted genotype was co-segregated with the
mvp phenotype. Furthermore, sequence analysis indi∗

136

Fukui Prefectural University

Fig. 1. M3 line segregating mvp2 (arrow) and WT plants.

cated that a deletion of the region that includes WAP1
occurs in mvp1 genomic DNA.
Total RNAs were extracted from leaves of WT and
mvp M3 plants, and cDNAs were synthesized from thetotal RNAs. To examine the WAP1 gene expression
in the M3 plants, RT-PCR analysis was conductedusing WAP1 gene-specific primer.3) WAP1 gene expression was started just before the timing of phasetransition from the vegetative to reproductive stage,
and continued during the vegetative stage in WT
plants. On the other hand, no expression of WAP1
was started in mvp mutants. Furthermore, no expression of the wheat FLOWERING LOCUS T ortholog,
WFT, was observed in mvp mutants. FT is a promoterof the phase transition that acts in the photoperioddependent pathway in Arabidopsis.4) Expression analysis of WFT indicated that WFT functions in the
promotion pathway of phase transition after a longday photoperiod in wheat (unpublished data). We also
found that WFT was weakly expressed in the WAP1
cosuppression transgenic line compared with nontransformants (unpublished data). These results, together
with those of WFT expression analysis in mvp mutant, suggest that WAP1 and WFT are up-regulated
by each other and function in a coordinated manner.
In conclusion, the mutation gene of mvp is WAP1,
which is an indispensable gene for transition from thevegetative to reproductive phase in wheat.
References
1) K. Murai: Wheat Inf. Serv. 100 (2006), in press.
2) Y. Komeda: Annu. Rev. Plant Biol. 55, 521 (2004).
3) K. Mura et al.: Plant Cell Physiol. 44, 1255 (2003).
4) P. K. Boss et al.: Plant Cell 16, S18 (2004).

RIKEN Accel. Prog. Rep. 39 (2006)

Isolation of morphological mutants of rice
induced by heavy-ion irradiation
T. Abe, H. Takehisa,∗1 M. Yasuda,∗2 Y. Hayashi, H. Saito, H. Ichida,∗3 T. Shirao,∗4 R. Onuma,∗5 H. Ryuto,
N. Fukunishi, Y. Miyazawa,∗1 H. Tokairin, H. Nakashita, T. Kudo, and T. Sato∗1
In a previous paper, we reported the eﬀect of Cion beams on the induction of rice mutations.1) In thispaper, aggregate data from 2000 to 2004 represent the
mutational eﬀect of heavy ions on rice. We have also
isolated a lesion-mimic mutant and a tall mutant fromprogenies of imbibed seeds irradiated in 2002.
The rice seeds (Oryza sativa L. cv. Nipponbare) were
soaked for 3 days in water at 30◦ C without light. The
seeds that imbibed water were exposed to C or Ne ionsaccelerated to 135 MeV/nucleon by the RRC withina dose range of 10 to 160 Gy. LET values of the C
and Ne ions corresponded to 22.5 and 63.0 keV/µm, respectively. After irradiation, the seedlings were transplanted to the paddy ﬁeld. M2 seeds were harvested
separately from each M1 plant approximately 6 months
after irradiation. M2 seeds were sown on seedbeds
and grown in a greenhouse under daily conditions of
30◦ C for 11 h (daytime) and at 25◦ C for 13 h (night).
One month later, chlorophyll-deﬁcient mutants (CDM)
were observed.
Sixty M2 progenies which consisted of 1033 individual lines (C ion) and 13 M2 progenies in 273 lines (Neion) were segregated into green plants and CDM, that
is, albina (albino), xanta (yellow leaves), chlorina (palegreen leaves), and striata (striped leaves) phenotypes.
The optimal CDM induction was obtained for irradiation at 40 Gy for C ions and 10 Gy for Ne ions (Fig. 1).
We successfully isolated a bronzing mutant (7-3b) fromthe 10 Gy Ne-ion irradiation and a tall mutant (6-99t)
from the 40 Gy C-ion irradiation (Table 1). These twomutants were selected as homozygous phenotypes in
M3 progenies. The 6-99t strain increased plant heightfrom 87.2 to 101.6 cm. However, the ﬁrst heading dateof M3 plants was the same as the control on August 24,
2004. The 7-3b strain had brown spots on leaves similar to lesions induced by pathogens (Fig. 2). Brown
spots were visible from an early development stage.
Some mutants are resistant to rice blast and bacterial

Fig. 1. Frequencies of CDP induced with ion beam irradiation. : C ion and : Ne ion.

Fig. 2. Leaves of 19-week-old rice plants. WT: wild type(control) and 7-3b.

blight in this type of lesion-mimic mutants.2) Disease
resistance of the 7-3b strain was examined by an inoculation test of rice blast disease caused by Magnaporthe grisea, one of the most economically importantdiseases. Four-leaf stage rice plants were inoculatedwith M. grisea race 007, and spreading necrotic lesions caused by the pathogen which appeared on the
fourth leaf were counted ﬁve days after the inoculation.
The number of lesions on the 7-3b strain was signiﬁcantly less than that of control plants, indicating thatthe mutant exhibited enhanced resistance against rice
blast disease. The mutants of rice induced by ion-beamirradiation could be important as genetic resources forresearch in plant functional genomics.

Table 1. Morphological mutants induced with ion-beam irradiation.
Plant height (cm) Panicle weight (g)§Control
87.2 ± 1.9
2.53 ± 0.13
7-3b80.9 ± 2.0
1.37 ± 0.04
6-99t
101.6 ± 1.6
2.63 ± 0.07§
Measured for the longest panicle.
± SE
∗1
∗2
∗3
∗4
∗5

Graduate School of Life Sciences, Tohoku University
Mayekawa MFG. Co., Ltd.
Faculty of Horticulture, Chiba University
Kagoshima Biotechnology Institute
Faculty of Science, Tokyo University of Science

No. of grains
102 ± 670 ± 3109 ± 3

Fertile grains (%)§
95.0 ± 0.8
85.5 ± 2.4
90.9 ± 0.9

1,000 grains weight (g)24.6 ± 0.5
21.2 ± 0.4
25.0 ± 0.2

References
1) T. Abe et al.: RIKEN Accel. Prog. Rep. 38, 132 (2005).
2) R. Mizobuchi et al.: Plant Sci. 163, 345 (2002).

137

RIKEN Accel. Prog. Rep. 39 (2006)

Characteristics of glutinous rice mutants induced bynitrogen-ion beam irradiation
K. Ohkoshi,∗1 T. Nagashima,∗1 Y. Nishikawa,∗1 R. Hayashi,∗1 M. Ohara,∗1 Y. Ito,∗1 T. Abe,K. Sakamoto,∗2 N. Fukunishi, and H. Ryuto
Recently, heavy-ion beam mutagenesis has been
widely recognized as a highly eﬀective technique formutation breeding. In this report, characteristics ofglutinous rice mutants induced by N-ion beam irradiation on nonglutinous rice seeds are presented.
The 680 grains of dry seeds, nonglutinous rice
(Oryza sativa L. cv. Chiba No.19), were irradiated by
N ions at 135 MeV/nucleon with a dose range of 10
to 200 Gy in 1999. The M2 seeds harvested from theseeds that had been irradiated by the same dose weremixed, and 400 seeds were selected randomly to obtainM3 seeds. The grains of the M3 generation that had
a cloudy endosperm were selected to produce a newvariety of glutinous rice in 2002. The superior lines
from two generations, descendants (M5 ) were selected
in 2004.
The N-ion irradiation did not decrease the germination rates. The survival rates decreased when theseeds were irradiated with doses higher than 50 Gy.
The rates of sterile M2 plants increased when the doses
were higher than 100 Gy. A 200 Gy irradiation produced the highest percentage, shown to be 2.2% ofgrains with a cloudy endosperm (Table 1). The numbers of selected M5 lines were 23, 13, 1, 1, and 15,
which resulted from 10, 20, 50, 100, and 200 Gy irradiation, respectively. The amylose contents of seeds inselected lines were measured to determine whether theseeds were glutinous or nonglutinous. The resulting
amylose content ratios were approximately the same as
those of the standard variety of glutinous rice cv. Himenomochi within the range from −0.36% to +0.07%.
Therefore, the selected lines are glutinous rice mutants.
The characteristics of glutinous rice mutants were observed at 10, 20 and 200 Gy lines. The heading periodsof the selected lines were longer than that of the control (Fig. 1). The ﬁrst heading dates of 10 and 20 Gylines were earlier than that of the control. On theother hand, that of the 200 Gy line came from 1 to

6 days later than the control. The diﬀerence in themean values of culm length between 20 Gy lines andthe control was 5 cm, and 200 Gy lines and the control line was 11.6 cm. The culm length of one of the
200 Gy lines, 70.4 cm, was the longest, and it was approximately 10 cm longer than the mean value of thecontrol (Fig. 2). Many plants that appeared in 10 Gylines have panicle lengths shorter than the mean valueof the control, 18.9 cm. Most of the plants in 20 and
200 Gy lines had longer panicle lengths than the plants
in the control. As the dose increased, the culm lengthand the number of panicles had a tendency to increase.
Therefore, we succeeded in producing glutinous ricemutants that have various heading dates and yielding
abilities.

Fig. 1. Days from first to full heading on each dose ofglutinous rice mutants in 2004 (M5 ). The first heading date means 20% headed, the heading date means
50% headed. Each symbol Fi H 
Fu shows the dateof the means of each growth stage. No. of lines for examination: 23 for 10 Gy, 13 for 20 Gy and 15 for 200 Gy.

Table 1. Percentage of grains with cloudy endosperm inrice seeds irradiated by N-ion beam in 2002 (M3 ).

Fig. 2. Rate of panicle length and culm length on each dose
glutinous rice mutants in 2004 (M5 ).
∗1
∗2

138

Chiba Prefectural Agriculture Research Center
Japan Atomic Energy Research InstituteRIKEN Accel. Prog. Rep. 39 (2006)

Mutation induction by heavy-ion beam irradiation in daylily,
Hemerocallis hybrida
H. Saito, J. Amano,∗ S. Mori,∗ N. Fukunishi, H. Ryuto, M. Nakano,∗ and T. Abe
Hemerocallis species (daylilies) belonging to the Liliaceous family are very popular garden plants becauseof their various ﬂower colors and forms, and high resistance to biological and environmental stresses. The
breeding of these species has long been carried out byinter- and intra-speciﬁc sexual hybridization, sport selection, polyploidization, and hybridization between
plants of diﬀerent ploidy levels.1) Recently, heavyion beams have been frequently utilized for breeding by artiﬁcially inducing mutations in various plant
species.2) Therefore, we examined the possibility of applying heavy-ion beam irradiation to the development
of daylily mutants.
Adult plants of H. hybrida cv. Stella d’Oro wereprecultured at 25/22◦ C (day/night) for one week following cold storage at 4◦ C for 3 months. Sections (ca.
6 cm long), each of which includes the crown, were irradiated with 12 C-ion beams (135 MeV/nucleon, LET;
23 keV/µm) at a dose of up to 10 Gy. After the irradiations, sections were planted to pots and were grown
at 25/22◦ C (day/night) under a 16 h/8 h (light/dark)
photoperiod for 9 months. All ﬂowers were artiﬁciallyself-pollinated at anthesis.
All the control non-irradiated crowns sprouted
within 2 months after the planting, and all crowns thatsurvived after the irradiations also sprouted within 3month culturing. The decrease in survival rate was observed with the increase in dose; the 10 Gy-irradiation
treatment decreased the survival rate to 65%. In thecase of 7.5 Gy-irradiation treatment, ﬂowering rate andthe numbers of scapes, ﬂowers and seeds decreased

to one-half of those of controls. On the other hand,branching was promoted by the irradiations at 2.5 and
5 Gy, and the number of branchings in plants irradiated at 7.5 Gy was similar to that in the control plants(Table 1).
The eﬀects of irradiation on mutation induction are
shown in Table 2. Abnormal ﬂowers and variegatedleaves were observed in the lines irradiated at the range
from 2.5 Gy to 7.5 Gy. The abnormal ﬂowers werecharacterized by the distortion or lobation of pistils
and tepals, or an increased number of tepals. Variegated leaves partially developed during the sprouting
and branching. After branching, three lines consisting of only variegated leaves were obtained by 5 and
7.5 Gy irradiations. Two lines consisting of shorter
leaves than those of the control lines with the average
length of 38.5 cm were obtained by 2.5 Gy and 7.5 Gy
irradiations.
Morphological alterations such as the formation ofabnormal ﬂowers, variegated leaves and shorter leaves
were observed in several plants at the ﬂowering stage.
These mutant lines were transplanted in a ﬁeld, andtheir detailed characterization is in progress.
References
1) L. Hill and N. Hill: Daylilies: The perfect perennial(Storey Publishing, North Adams, 1991).
2) T. Abe, Y. Miyazawa, H. Saito, S. Yoshida, N.
Fukunishi, H. Ryuto, and Y. Yano: Proc. 14th Symp. on
Accelerator Science and Technology Tsukuba, 2003-11(KEK, 2003), p. 578.

Table 1. Eﬀects of C-ion beam irradiation on growth of Hemerocallis hybrida.a

Table 2. Eﬀects of C-ion beam irradiation on mutation induction in Hemerocallis hybrida.

∗

Faculty of Agriculture, Niigata University

139

RIKEN Accel. Prog. Rep. 39 (2006)

Sterile verbena cultivar produced by heavy-ion beam irradiation andwild species Verbena peruviana exhibit diﬀerent self-incompatible
phenotypes
H. Saito, Y. Hayashi, N. Fukunishi, H. Ryuto, T. Kanaya,∗ K. Suzuki,∗ and T. Abe
Garden verbenas (Verbena hybrida) of the Verbenaceae family are one of the most utilized bedding
plants because of their beautiful ﬂowers and vigorous
growth. They are a result of interspeciﬁc hybridization
among several species, and most of them frequently
produce seeds. Recently, a sterile mutant has been
isolated from the cultivar ‘Coral Pink’ of the Temari
series (Suntory Flowers Ltd., Osaka, Japan) by mutation induction using heavy ions.1) In our previous
study,2) we described that the sterile mutant line exhibits self-incompatibility (SI) similarly to that in teak(Tectonia grandis) of the Verbenaceae family.3) SI is
an important outbreeding mechanism, and is useful toplant breeders as it provides an eﬃcient pollination
control system for the commercial production of hybrid
seeds. However, it remains to be elucidated whether
SI exists in wild Verbena species. In this study, therefore, we investigated whether the sterile mutant is arevertant that regained the SI phenotype.
Wild-type V. peruviana (VP), one of origins of theTemari series, and the sterile mutant of ‘Coral Pink’(SC) and its original fertile one (FC) were used. Seed
set following pollination tests and the behavior ofpollen tubes in pistils after self-pollination were investigated as in our previous report.2)
Although the reciprocal pollination between VP and
FC or SC produced many seeds, self-pollinated VP
ﬂowers produced no seeds (Table 1). The former result
indicates that VP also has functional male and female
gametes, the same as SC and FC. The latter result
suggests that VP has an SI phenotype similar to thatof SC2) and teak.3) To clarify the mechanism of SI in
Verbena, the behavior of pollen tubes in pistils wascompared among self-pollinated three lines (Fig. 1).

Fig. 1. Fluorescence micrographs of self-pollinated pistils
3 h (stigma) and 24 h (lower part of style and ovary)following pollination. Pistils were stained with decolorized aniline blue to localize callose. Arrowheads show
pollen tubes.

Pollen germination in stigma was observed in all lines.
However, almost all self-pollen tubes of SC reached thelower region of the style or the upper regions of theovary; on the other hand, the pollen tube growth of
VP was inhibited at the upper part of the style. Interestingly, a distinct diﬀerence in reaction in self-pollen
rejection was observed between SC and VP. According
to observations in the self-pollen-inhibited area, the SI
system in SC is late-acting SI as described in teak;3)on the other hand, that in VP is likely to be gametophytic SI which is described in other families such as
Solanaceae and Rosaceae.4) Detailed characterizationand genetic analysis of the SI phenotype in the genus
Verbena are in progress.
References

Table 1. Seed set following self- and cross-pollinations atanthesis.

∗

140

Production Department, Suntory Flowers Ltd.

1) K. Suzuki et al.: RIKEN Accel. Prog. Rep. 35, 129(2002).
2) H. Saito et al.: RIKEN Accel. Prog. Rep. 38, 137(2005).
3) S. Tangmitcharoen and J. N. Owens: Ann. Bot. 80, 401(1997).
4) K. R. Shivanna: Pollen Biology and Biotechnology (Science Publishers, Inc., New Hampshire, 2003).

RIKEN Accel. Prog. Rep. 39 (2006)

Ion beam sensitivity of ornamental plants
T. Kanaya,∗ K. Suzuki,∗ K. Miyazaki,∗ H. Saito, Y. Hayashi, H. Ryuto, N. Fukunishi, and T. Abe
The heavy-ion beam is known as an eﬀective mutagen for various plants. Riken and Suntory Flowers
Ltd. have jointly developed some new ornamental varieties of Verbena and Petunia using heavy-ion-beamirradiation.1) We report here the sensitivity of someornamental plants to heavy-ion beams.
Plant materials developed by Suntory Flowers Ltd.
were used. In vitro nodal culture materials of ‘Million
Bells Trailing Pink’ (MBTP, Calibrachoa sp.), ‘Senetti
Blue’ (SNB, Senecio cruentus × S. heritierii ), ‘Little
Tutu Lemon Mist’ (LTLM, Scoparia sp.), ‘Sun Parasol Red Mini’ (SPRM, Mandevilla Hybrid) and leafdiscs of ‘Summer Wave Large Pink & White’ (SWLP,
Torenia hybrida) were irradiated with C-ions. The
survival rates of nodal culture materials of MBTP,
SNB, LTLM and SPRM were calculated at the timeof acclimatization (Fig. 1). All of developed shootsof SWLP were acclimatized after shoot development
and counted. SWLP was also irradiated with Ne-ionsand the number of shoots was counted in the sameway. In the Fe-ion irradiation, leaf discs of ‘Summer
Wave Blue’ (SWB), ‘Summer Wave Violet’ (SWV) and‘Summer Wave Amethyst’ (SWA) were used and developed shoots were acclimatized and counted.
The survival rates of MBTP, SNB, LTLM andSPRM irradiated with C-ions are shown in Fig. 1. The
rates of MBTP and LTLM decreased with increasing
dosage. SPRM exhibited almost the same tendency ofalteration in survival rate. The LD50 of MBTP was
between 10 to 20 Gy and that of SPRM was between
20 to 30 Gy. On the other hand, the survival rate of
SNB showed no particular alternation in the range of
5 to 50 Gy.
The number of developed shoots from leaf discs of
SWLP decreased with increasing dosage in the range of
10 to 50 Gy (Fig. 2). In the case of Ne-ion irradiation,
the number of developed shoots of SWLP markedly
decreased in the range of 10 to 40 Gy (Fig. 3). When
SWB, SWV and SWA were irradiated with Fe-ions,the number of obtained shoots declined in the range of

Fig. 2. Number of shoots developed from 25 pieces of leafdiscs of SWLP irradiated with C-ion beam.

Fig. 3. Number of shoots developed from 25 pieces of leafdiscs of SWLP irradiated with Ne-ion beam.

20 to 50 Gy (Fig. 4).
From these results, in C-ion irradiation, we supposethat 10–20 Gy for Calibrachoa, 20–30 Gy for Mandevilla, over 20 Gy for Scoparia and over 50 Gy for Senecio
are eﬀective dosages in the survival of these genera. In
the irradiation for Torenia, 10–50 Gy of C-ions, 10–
40 Gy of Ne-ions and 20–50 Gy of Fe-ions have eﬀects
on the survival. However, we should pay attention todiﬀerences in sensitivity among varieties of the same
genus.
In addition to the examination of sensitivity toheavy-ion beams, we are also studying the relationshipamong ion type, dosage and phenotypic mutation.

Fig. 4. Number of shoots developed from 25 pieces of leafdiscs of SWB, SWV and SWA irradiated with Fe-ion
beam.
Fig. 1. Survival rates of MBTP, SNB, LTLM and SPRM
irradiated with C-ion beam.
∗

Suntory Flowers Ltd.

Reference
1) K. Suzuki et al.: Radiation & Industries 99, 40 (2003).

141

RIKEN Accel. Prog. Rep. 39 (2006)

Eﬀect of heavy-ion beam irradiation on cyclamen
M. Sugiyama,∗ T. Terakawa,∗ H. Saito, Y. Hayashi, N. Fukunishi, H. Ryuto, and T. Abe
Cyclamen (Cyclamen persicum) is one of the mostpopular potted plants in winter in Japan. Thus far, a
new variety of cyclamen has been developed mainly bya crossbreeding method. Using this method, it takes
a long time to develop this new variety because it requires many crossbreedings to improve the plant. Recently, mutation breeding of ornamental plants andﬂowers by heavy-ion beam irradiation has been performed. This new method induces mutations in plants
at a high frequency, which shortens the breeding process. The sterile mutants of verbena1) and pelargonium2) and the ﬂower color mutants of chrysanthemum3) and carnation4) were developed by this method.
In this study, we examined the eﬀect of heavy-ion beamirradiation on the viability of cyclamen. This is theﬁrst step that leads to an establishment of a mutation
breeding of this plant.
A callus, a somatic embryo and a plantlet of cyclamen (cv. Hokko mini no.1) were irradiated with a
12
C ion beam (135 MeV/nucleon, LET 23 KeV/µm),
then the eﬀect of the irradiation was examined. 1)
A callus was produced by culturing a scape segment
for one month on MS medium containing kinetin and
2,4-dichlorophenoxyacetic acid. 15 calli were irradiated at doses of 10, 20, 40, 60, and 80 Gy in eachexperiment. Three months after the irradiation, theamount of somatic embryo formed on the callus wasdetermined. 2) Somatic embryos were produced byculturing scapes for three months on the same medium
as above. Then 210 somatic embryos were irradiatedin each experiment in the same way as the callus was.
Two months after the irradiation, the survival rate of
the somatic embryo was examined. 3) A plantlet was
produced by germinating the somatic embryo on MS
medium containing benzylaminopurine and naphthylacetic acid, and 70 plantlets were irradiated in eachexperiment as above. Three months after the irradiation, the survival rate of the plantlet was determined.
Somatic embryogenesis from a callus was suppressedby heavy-ion beam irradiation (Fig. 1). Severer suppression was observed at higher irradiation doses. Only
0.2 g of somatic embryo was produced at a dose of
80 Gy while 1.1 g was obtained in the control that was
not irradiated. The somatic embryos and plantlets
were injured by the heavy-ion beam irradiation. Only
11% of the embryos irradiated at 60 and 80 Gy survived while 41% of the control survived (Fig. 2). All
the plantlets irradiated at 40 Gy and higher died while
67% of the control survived (Fig. 3). These results
suggest that the somatic embryo is more resistant toheavy-ion beam irradiation than the plantlet is. We∗

142

Hokko Chemical Industry Co., Ltd.

Fig. 1. Eﬀect of 12 C ion beam irradiation on somatic embryogenesis. The fresh weight of the somatic embryo
produced on a callus was examined.

Fig. 2. Eﬀect of 12 C ion beam irradiation on survival rateof somatic embryo.

Fig. 3. Eﬀect of 12 C ion beam irradiation on survival rateof plantlet.

are now identifying the most suitable stage of a cyclamen culture for mutation induction by heavy-ion beamirradiation.
References
1) K. Suzuki et al.: RIKEN Accel. Prog. Rep. 35, 129(2002).
2) M. Sugiyama et al.: RIKEN Accel. Prog. Rep. 38, 136(2005).
3) S. Nagatomi et al.: Breed. Sci. 48 Suppl. 1, 220 (1998).
4) M. Okamura et al.: Nucl. Instrum. Methods Phys. Res.
B 206, 574 (2003).

RIKEN Accel. Prog. Rep. 39 (2006)

STJ cryogenic detector response to α-particles
S. Bishop, H. Sato, Y. Takizawa, M. Kurakado, H. Shimizu, and T. Motobayashi
The advent of low energy radioactive ion beam facilities will provide unprecedented opportunities to probe
the nuclear physics processes that occur within astrophysical events such as super novae, novae, γ-ray andx-ray bursts. A foremost objective of these low energy radioactive ion beam facilities will be to measure
the rates of proton and α-particle capture reactions,and thus provide new insights into explosive nucleosynthesis. These reactions occur at sub-Coulomb barrier energies, posing severe experimental constraints on
beam-induced backgrounds: at these low energies, particle identiﬁcation, using gas ionization chambers andsilicon detectors, with the standard ∆E − E methods
fails, due to insuﬃcient energy resolution of these detectors.
Low temperature cryogenic detectors have the potential to overcome this problem. The detector reported herein consists of a single crystal sapphire
substrate 12 mm×12 mm×0.4 mm in size.1) Fabricatedonto one side of this substrate are 4 independent arrays of 864 series-connected superconducting tunnel
junctions (STJ); each STJ is 110 µm in diameter andis constructed from a layering of 200 nm Nb/50 nm
Al/≈ 2 nm AlOx /50 nm Al/150 nm Nb. Figure 1 showsa photograph of the detector, with relevant components labelled. The active detection area of the detector is that region within the 4 rectangular arrays, andit has an area of 8 mm×8 mm.
These detectors are essentially calorimeters and theprinciple of particle detection is now brieﬂy described.
A charged α-particle impinging on the sapphire substrate has its kinetic energy converted into ionizationenergy loss (30%) and heat (70%). Provided that thedetector is cooled to ≈ 350 mK, the tiny temperaturechange of the detector substrate can be directly detected. The heat manifests itself in the form of lattice phonons. Those phonons with energy Ep ≥ Ω,
where Ω is the energy required to break a Cooper pairin Nb, interact with the superconducting Nb base ofeach STJ producing excited electrons which can thentunnel across the AlOx barrier,2,3) thereby creating anelectrical signal representative of the incident particle’s
total energy.
The detector was attached to a gold plated copper
mounting plate by applying a small dab of varnish under each corner of the sapphire substrate. This mounting plate, along with a calibrated 241 Am α-source, wasthen attached an “L”-shaped copper holder using common screws for both. Sandwiched between the brass
mounting plate and copper holder, and 5 mm awayfrom the α-source, was a thin strip of aluminized mylar
with a ≈1 mm diameter hole pierced through it, serving as a collimator to prevent α events landing directly
above any of the STJ arrays. The distance between the
α-source and facing surface of the detector was 7 mm.
This geometry allowed a circular area ≈ 4 mm in diameter, of the detector active area, to be uniformly irradiated by the source. Figure 2 schematically shows theexperimental set-up just described. This arrangement
was mounted onto the cold stage of a 3 He cryostat
and brought to an (unregulated) operating temperature T ≈ 350 mK. Charge sensitive preampliﬁers (Ortec 142 A) were used to indepedently amplify the signals from each of the 4 STJ arrays. These signals were
further processed by Canberra spectroscopic shaping
ampliﬁers and fed to peak sensing ADC modules.
A 4-fold software coincidence requirement between
the STJ array signals was imposed on the data thus
obtained. Event-by-event summation of the 4 arraysignals results in a total energy measurement of eachdetected α-particle; however, this quantity is highly
dependent1) on the arrival position of the incident αparticle. This position dependence can be corrected
for by using the position information as determinedby charge division between the horizontal and verticalpairs of STJ arrays. Referring to Fig. 1, the x positionof an event is deﬁned as: VC /(VA + VC ), and analogously we have for the y position: y = VB /(VB + VD ),where, by these deﬁnitions, the coordinate origin is po-

Fig. 1. Schematic side-view of STJ detector mounting on
the 4 He cold stage.

Fig. 2. Schematic side-view of STJ detector mounting on
the 4 He cold stage.

143

sitioned in the lower left corner of the detector and V
is the voltage signal from an array. The entire spanof (X, Y ) values is then subdivided into N × N cells,
forming a “virtual” segmentation of the detector’s active area, as depicted in Fig. 1. For each cell having
suﬃcient statistics, a total energy spectrum is formed
and the mean total energy value, E, is stored. The
zeroth order position correction to the total energy
data involves creating a correction factor R0 , for eachcell’s energy values, comprised of R0 = Emax /E,
where R = Emax is the maximum mean energy
value of all cells. Higher order corrections can be performed by taking the corrected R0 values and doing a2-dimensional Taylor series expansion in the position
coordinates. To ﬁrst order, the expanded correction
factor for any position coordinate (X, Y ) is given by:
r = R0 +R1 − R0
R2 − R0(X − X0 ) +(Y − Y0 ) (1)X1 − X0
Y2 − Y0

where R0 is the zeroth order correction factor, previously described, of the cell in which the particular(X, Y ) event occurs (the event cell); X0 and Y0 are thecoordinates deﬁning the centre of the event cell; R1
and R2 are the zeroth order correction factors for thenearest neighbouring cells, in the x and y directions,
respectively. For these data, N = 30 and the minimum
statistics required for each cell was 20 events; cells withless than this number of events were omitted from theanalysis.
Figure 3 shows the α-particle energy spectrum obtained with this detector after approximately 1 hourof data taking; it is highly non-Gaussian and is ≈ 72
channels wide in FWHM. In contrast, the insert shows
the same spectrum after applying the previously described position correction procedure of Eq. (1); theresult is a highly Gaussian spectrum ≈ 18 channels
wide in FWHM. The FWHM energy resolution obtained is 2.85%. This result contrasts with typical silicon detector energy resultions that are typically < 1%
for 241 Am alpha particles. More study is required tounderstand the performance of the detector in regards
to energy resolution. For example, an important parameter to control for future studies will be the heat
conduction paths from the detector substrate to thehelium cold stage; being able to more precisely control the path locations and their surface contacts withthe substrate could be adjusted to optimize phonon
losses to the thermal bath and, therefore, presumably
improve the energy resolution.
Finally, another source of improvement for future
detector design is in the electronics used for data acquisition. Figure 4 shows the corrected mean energy

144

Fig. 3. Uncorrected (solid line) and corrected (insert) αparticle energy spectrum.

Fig. 4. Time instability of α-particle energy signals.

events as a function of event time (both in arbitrary
units) during the course of the experiment. Evident
in the ﬁgure is a sizable instability in the total energy signals. The source of this instability is not yet
known, but one possible source could be the ampliﬁer system used to obtain the signals. Development
is now underway to design and construct preampliﬁers
that will be placed in the cryostat, cooled by the liquid
nitrogen cooling jacket, and positioned close to the detector. In this way, electronic noise should be reduced
and, perhaps, the instability observed in Fig. 4 will beeliminated.
References
1) M. Kurakado et al.: Nucl. Instrum. Methods Phys. Res.
A 506, 134 (2003).
2) M. Kurakado: X-Ray Spectrom. 28, 388 (1999).
3) M. Kurakado: X-Ray Spectrom. 29, 137 (2000).

RIKEN Accel. Prog. Rep. 39 (2006)

Mixed-wave RF-application system for Q-moment measurements
M. Takemura,∗ M. Uchida,∗ D. Kameda, H. Ueno, G. Kijima,∗ A. Yoshimi, K. Shimada,∗ D. Nagae,∗
T. Haseyama, T. Arai,∗ S. Suda,∗ T. Inoue,∗ K. Takase,∗ and K. Asahi
By the β-NMR method with spin-polarized RI
beams in RIPS, we measured the magnetic moments of30
Al and 32 Al.1) We apply this technique to the measurement of the nuclear quadrupole moments which areinteresting from the viewpoint of studying nuclear deformations around “the island of inversion”.2) The Qmoment measurement, however, is more complicatedthan the β-NMR experiment. This is because we must
control 2I diﬀerent resonance frequencies according
to quadrupole splitting, where I denotes the nuclear
spin. Otherwise, the β-ray asymmetry change would
be much smaller than that in the β-NMR experiment.
We have developed a new RF-application system to realize spin manipulation3,4) such that all of the 2I transitions between magnetic substates are induced using
an RF pulse, the frequency component of which includes the 2I resonance frequencies.
Using a crystal sample with an electric ﬁeld gradient(eq) having cylindrical symmetry about the principal axis, the 2I frequencies are given as f m↔m−1 =
2
3 cos2 θc −1
3
m − 12 , where m andf0 − e hqQ 2I(2I−1)
2
f m↔m−1 denote the quantum number of the magnetic
substate and the resonance frequency corresponding
to the RF transition between m and m − 1, respectively. The Larmor frequency and the quadrupole
2
coupling constant are denoted as f0 and e hqQ , respectively, and the angle between the static magnetic
ﬁeld and the crystalline c-axis parallel to the principal axis of eq is denoted as θc . In an experiment,a Q-moment region is searched with linear sweeps ofthe 2I frequencies f m↔m−1 by the adiabatic fast passage (AFP) method. There are two ways in which
to apply the 2I frequencies. i) The waveform w(t) is
generated by superposing sine waves, such as w(t) =



m↔m−1
t , where a(t) denotes thea(t) −I+1
m=I sin 2πfamplitude modulation (AM) of the RF ﬁeld, as shownin Fig. 1 (a). A trapezoidal shape is typically employedfor AM. We call the waveform w(t) a mixed-wave RF
pulse. The mixed-wave RF pulse is useful for very
short-lived nuclei because of the short RF application

time. ii) The sine waves are sequentially connected,
as shown in Fig. 1 (b). In this case, we can employ astrong RF ﬁeld for each sine wave. This is advantageous for spin reversal by the AFP method. The RF
applicationtime, however,
becomes longer. RF appli2I
cations forn=1 n repetitions are needed to reverse
the direction of spin polarization because the population of the m substate could be exchanged with thatof the m − 1 substate by the sweep over f m↔m−1 . The
waveform w(t) is converted into numerical data for a
waveform generator, AWG615 (Tektronix). The time
step of the data is determined from the time resolution
and the memory length of the device.
In order to check this system before the Q-momentmeasurement of neutron-rich Al isotopes, we compared
the magnitude of the change of the β-ray asymmetryof 12 B obtained by Q-moment measurement using thisnew system with the magnitude obtained by β-NMR
measurement. Spin-polarized 12 B was produced by the
projectile fragmentation of 70.0 MeV/nucleon 18 O projectiles on a 429 mg/cm2 thick Nb target. The 12 B
fragments were separated isotopically in RIPS. In order to induce spin polarization, the emission angle andthe outgoing momentum were selected to be 2.1◦ ∼6.5◦
and 14.2 ± 0.3 GeV/c, respectively. The spin-polarizedfragments were implanted in a stopper placed at theend of the RIPS. A stack of thin Pt foils was employedin the β-NMR measurement. In the Q-moment measurement, we employed a stack of single-crystal Mg
plates with the c-axis maintained parallel to the static
magnetic ﬁeld B0 = 30.5 mT. The electric ﬁeld gradient of the Mg sample and the Q-moment value weretaken from the literature.4,5)The β-asymmetry change obtained using this new
system was Aβ P = −1.7 ± 0.1%, which was 30%
smaller than that obtained by β-NMR measurement,
where Aβ and P denote the β-ray asymmetry factor
and spin polarization, respectively. We consider thatthe reduction of the β-asymmetry change results fromthe inhomogeneous broadening of the spectrum dueto the position distribution of 12 B in the crystal sample. From the results, we conclude that the new RFapplication system is available for the Q-moment measurement.
References

Fig. 1. RF pulse for I = 3/2: (a) Mixed-wave (b) Sequential-wave∗

1) H. Ueno et al.: Phys. Lett. B 615, 186 (2005).
2) E. K. Warburton et al.: Phys. Rev. C 41, 1147 (1990).
3) E. Arnold et al.: Phys. Lett. B 281, 16 (1992).
4) T. Minamisono et al.: Phys. Rev. Lett. 69, 2058 (1992).
5) H. Izumi et al.: Phys. Lett. B 366, 51 (1996).

Department of Physics, Tokyo Institute of Technology

145

RIKEN Accel. Prog. Rep. 39 (2006)

Development of recoil particle detector systemfor proton elastic scattering
H. Takeda, H. Sakurai, T. Ichihara, T. Suda, Y. Watanabe, T. Ohnishi, H. Sakaguchi,∗1 T. Murakami,∗1
S. Terashima,∗1 J. Zenihiro,∗1 Y. Iwao,∗1 T. Fukui,∗1 H. Matsumoto,∗1 Y. Matsuda,∗2 and M. Kitayama∗2
Density distributions of nuclear charge and matterare one of the most fundamental information in nuclear
physics. However, unambiguous information about
matter and neutron distributions in nuclei is diﬃcult toobtain, since electromagnetic interaction provides little
information about neutrons. Among various stronglyinteracting probes, proton elastic scattering at intermediate energies (200 – 400 MeV) has served as one of
the best methods for probing matter density distributions in nuclei. For stable nuclei, we have succeededin extracting neutron distributions from proton elastic
scattering measured at RCNP in Osaka University.1)
In the case of unstable nuclei, an inverse kinematic
method is the only way to perform proton elastic scattering, in which the beam is composed of the nucleus ofinterest. Scattering angles and energies of recoil protons must be measured to distinguish between elastic
and inelastic scattering.
To perform such measurements at the RIBF being
constructed in RIKEN, we developed a recoil particle detector system, which consists of a solid hydrogentarget (SHT),2) multiwire drift chambers (RDCs) for
determining scattering angles, a thin plastic scintillator for triggers, and NaI(Tl) scintillators3) for measuring total energies of recoil particles. In addition
to the recoil particle detectors, another set of multiwire drift chambers (BDCs), a delay-line PPAC with a
150 mm×100 mm active area and 2 mm pitch scintillating ﬁber (SciFi) detectors with a 120 mm×50 mm active area were developed to measure the incident beam.
The BDC will be located just upstream of the target
to measure the position and angle of the beam at thetarget position. The PPAC and SciFi detectors will be
installed at the dispersive focal plane of the beam line
to select the momentum of the beam.
We performed three experiments this year. The ﬁrst
one was performed at the RIKEN E1C course in June.
The recoil particle detectors were fully installed for theﬁrst time. A schematic view of the experimental setup
is shown in Fig. 1. The BDC was not installed because
it was under construction at that time. A 0.5-mmthick CH2 target was used instead of the SHT. An
40
Ar primary beam at 95 MeV/nucleon was used. We
succeeded in observing recoil protons coinciding withthe beam events.
To evaluate the performance of the beamline detectors (BDC, PPAC and SciFi) at an intermediateenergy beam, the second experiment was performed
∗1
∗2

146

Department of Physics, Kyoto University
Department of Physics, Tohoku University

Fig. 1. Schematic view of experimental setup at E1C beamline.

at the SB2 beam line of the Heavy Ion Medical Accelerator in Chiba (HIMAC) in July. A 22 Ne primary beam at 390 MeV/nucleon was bombarded on a
30-mm-thick 9 Be target to produce an 20 O secondary
beam at 300 MeV/nucleon, which was directly applied
to the detectors. Position resolutions of 150 µm and500 µm in sigma were achieved for the BDC and PPAC
detectors, respectively. The eﬃciencies of the BDC
and SciFi detectors had plateaus at 90–99% even at
the maximum beam intensity of 106 particles/sec; however, we could not ﬁnd a plateau for PPAC eﬃciency.
Smaller energy losses at a higher energy region decreased eﬃciency and higher voltages were requiredfor operation. Discharge occurred before eﬃciency
reached a plateau. More investigations are required for
the PPAC detectors to work at an intermediate-energy
beam.
Finally we carried out the system integration test
again at the E1C course with an 40 Ar beam in October.
The experimental setup was almost the same as theprevious experiment except for BDC installation andthe 3-mm-thick SHT target covered with 60 µm kapton
windows on both sides. The analysis is now in progress.
We are planning to perform proton elastic scatteringoﬀ 20 O using the fully installed recoil particle detector
system at the HIMAC in this coming February.
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, p. 43.
2) T. Ohnishi et al.: RIKEN Accel. Prog. Rep. 38, 150(2005).
3) H. Takeda et al.: RIKEN Accel. Prog. Rep. 38, 146(2005).

RIKEN Accel. Prog. Rep. 39 (2006)

Neutron polarimeter for test of Bell’s inequality
K. Yako,∗1 K. Miki,∗1 S. Noji,∗1 H. Kuboki,∗1 T. Kawabata,∗2 and H. Sakai∗1
In 1935, Einstein, Podolsky, and Rosen (EPR)
claimed that quantum mechanics is incomplete interms of local realism, which is a classical conception ofnature.1) This argument was developed by Bell quantitatively and he showed that any local hidden variable
theory will result in an inequality, which contradicts
quantum mechanical prediction.2) We have started aseries of experiments to test the inequality in a protonproton system and a proton-neutron system by measuring the spin correlation.
To test Bell’s inequality in a proton-neutron system, proton-neutron pairs in 1 S0 are produced by
the d(d, pn[1 S0 ])pn[1 S0 ] reaction at Ed = 135A MeV.
The polarization of the proton is analyzed using a focal plane polarimeter (EPOL)3) installed at SMART
in the E4 experimental area. The neutron spin isanalyzed using a neutron polarimeter (NPOL). The
requirements for NPOL are an energy resolution of< 1 MeV and a ﬁgure of merit (FOM ≡ d A2y ) of
> 10−5 , where d and Ay are the double scattering
eﬃciency and the eﬀective analyzing power of NPOL,
respectively.
NPOL is located 18 m away from the target. A
schematic view of NPOL is shown in Fig. 1. NPOL
consists of four stacks of three planes of plastic scintillators. Each plane is made of six plastic scintillators(Bicron BC408) with dimensions of 10 × 60 × 3 cm3 ,which is viewed from both sides using photomultiplier tubes (PMTs) such that the positions are obtained from the timing information derived from the
PMTs. The typical position resolution is 3 cm in thelongitudinal direction of the scintillator. The neutron
polarimetry is based on the scattering asymmetry of
events in which two successive stacks are hit. The
ﬁrst stack serves as a neutron polarization analyzer(NA), whereas the next stack placed downstream by

55 cm serves as neutron catcher (NC). The polar angle
θ and azimuthal angle φ of neutron scattering in NA
are determined from the position information in NA
and NC. The most useful event is the elastic scattering of a neutron by a proton in NA and its detectionin NC. To eliminate signals due to charged particles
in the counter planes, three sets of thin plastic scintillators with dimensions of 20 × 60 × 0.5 cm3 are placedin front of each scintillator stack.
Ay is measured using the monoenergetic neutron
beam produced by polarized neutron beams producedby the 6 Li(d, n)X reaction at 0◦ at Ed = 135A MeV.
The typical polarization of the neutron beam, estimated from the polarization of the deuteron beam pd ,is pn = pd = 0.64 ± 0.02.4) The eﬃciency is calibratedusing neutrons produced by the 7 Li(p, n) reaction.5)
The incident neutron energies are obtained by thetime-of-ﬂight (TOF) technique. The intrinsic time resolution is 0.4 ns. The estimated energy resolution including the eﬀect of counter thickness is 0.9 MeV. The
sector method was applied to obtain Ay .4) The software cuts are optimized, as shown in Table 1, to obtainthe maximum FOM. The results are d = (4.2 ± 0.1) ×
10−4 , Ay = 0.28 ± 0.01, and FOM = (3.2 ± 0.1) × 10−5 .
The systematic uncertainty due to uncertainty in pd isestimated to be ±0.01. The FOM value is consistent
with similar NPOLs at IUCF6) and RCNP7) when the
FOM value is normalized by the total volume of theplastic scintillators.
Table 1. Optimized cuts4) applied to NPOL data.
Quantityφθ
Pulse height
Velocity ratioCutΦ = 66.8◦(θmin , θmax ) = (16.0◦ , 36.5◦ )> 5.0 MeVee
0.77–1.09

References

Fig. 1. A schematic view of NPOL.
∗1∗21) A. Einstein, B. Podolsky, and N. Rosen: Phys. Rev. 47,
777 (1935).
2) J. S. Bell: Physics 1, 195 (1964).
3) T. Saito et al.: RIKEN Accel. Prog. Rep. 37, 45 (2004).
4) K. Yako et al.: RIKEN Accel. Prog. Rep. 38, 156(2005), and references therein.
5) T. N. Taddeucci et al.: Phys. Rev. C 41 2548 (1990).
6) M. Palarczyk et al.: Nucl. Instrum. Methods Phys. Res.
A 457, 309 (2001).
7) T. Wakasa et al.: Nucl. Instrum. Methods Phys. Res. A
404, 355 (1998).

Department of Physics, University of Tokyo
Center of Nuclear Science, University of Tokyo

147

RIKEN Accel. Prog. Rep. 39 (2006)

Improvement of resolving power of multireflection time-of-flightmass spectrometer
Y. Ishida, M. Wada, Y. Yamazaki, and H. Wollnik∗
A multireﬂection time-of-ﬂight mass spectrometer(MR-TOF)1) has been developed for the precise massmeasurement of short-lived nuclei, which will be provided at the slow RI-beam facility (SLOWRI) of
RIKEN-RIBF.2) Bunched slow ions from SLOWRI willbe transferred to a linear ion trap to be compressed inphase space. The MR-TOF consists of two coaxiallyarranged ion mirrors. Ions ejected from the ion trap
and injected into the MR-TOF will move back andforth repeatedly between the ion mirrors in an energyisochronous manner. Thus, ion ﬂight time increases
while the ion bunch duration remains constant.
In a previous report3) a mass resolving power m/∆mof more than 60,000 was reported. With suﬃcient
statistics, i.e., more than three hundred ions theirmasses can be determined at less than 1 ppm. This
precision is suﬃcient for studying the global properties of the nuclear structure and for probing theoretical models. However, further system improvements
are desirable because of the small yields of ions in theregion far from the β-stability and because it would be
advantageous to separate ions of nuclei in the groundstate from those in the isomeric state. Also, it is necessary to eliminate the long tails of mass peaks caused
mainly by angle and energy straggling events in ionatom collisions.
By computer simulations using SIMION,4) it was
found that ions with large position deviations from thecentral axis at the middle between the ion mirrors are
responsible for the long peak tails in the mass spectrum. To eliminate such oﬀ-axis ions, a 3-mm aperture was placed in front of the ion detector. Figure 1
shows the obtained mass spectrum after a ﬂight timeof ≈3 ms using CO ions with a mass of 27.9949 u andN2 ions with a mass of 28.0061 u. From this spectrum we obtained a FWHM mass resolving power ofm/∆m ≈ 110,000, which is almost twice that previously reported.3) Moreover, the tails of the mass peaks
markedly decreased compared with those of the previous spectrum, so that the full width at one-tenthmaximum in mass unit decreased to one-third of that∗

148

University Giessen, Germany

Fig. 1. Mass spectrum of CO-N2 mass doublet after flighttime of ≈3 ms.

previously reported.
Since the back end of the entrance ion mirror
through which the ions must be injected is at a positive
potential with respect to the drift region between theion trap and MR-TOF even at the time of ion injection, the ions diverge when entering the ion mirror. To
minimize such divergence, it would be advantageous toplace round lenses between the ion trap and MR-TOF.
Another method for improving the emittance is tocool the ion trap and He buﬀer gas. This will reduce
not only the ion spacial distribution but also the average ion velocity in the trap. As a result, we expectthat shorter ion pulses are extracted from the trap,
thus, the mass resolving power is improved. We arepreparing to cool the ion trap using a cryogenic refrigerator.
References
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) Y. Ishida et al.: RIKEN Accel. Prog. Rep. 38, 164(2005).
4) D. A. Dahl: Int. J. Mass Spectrom. 200, 3 (2000).

RIKEN Accel. Prog. Rep. 39 (2006)

Development of low-energy muon beam line at the RIKEN-RAL
muon facility
Y. Matsuda, P. Bakule, Y. Ikedo,∗ K. Ishida, M. Iwasaki, S. Makimura,∗ T. Matsuzaki, Y. Miyake,∗
K. Nagamine, K. Shimomura,∗ and P. Strasser∗
Spin polarized positive muons (µ+ ) have a uniqueapplication in condensed matter physics as extremely
sensitive magnetic microprobes. Muons implanted intoa host material can convey information about the local
magnetic ﬁeld distribution and ﬂuctuations throughthe rotation or relaxation of their spin. The change ofmuon spin distribution can be observed by measuring
the angular distribution of positrons into which muonsdecay. This technique is called µSR, and has been usedfor various materials.
Until now, µSR experiments have been carried out
using “surface muons,” whose range is approximately
1.4 mm in water and 0.3 mm in iron. To study the magnetic properties of thin ﬁlms or multi-layered structures with the depth sensitivity on the nanometerscale, muon beams whose kinetic energy can be varied
from sub-keV to a few tens keV, with their uncertainty
within several percent, are required.
We have been developing a technique1) that allows
us to produce muons with kinetic energy as low as
0.2 eV by resonant laser ionization of thermal muonium
atoms (µ+ e− ). Since our ﬁrst generation of low-energymuons in 2001,2) we have increased the power of ionizing lasers, and have optimized both the focusing of
the incident muon beam and the transport eﬃciency
of low-energy muons after re-acceleration. This has resulted in the yield of low-energy muons being increased
by a few hundred fold to 15 µ+ /sec at the sample position. Our measurement shows no saturation of theyield with the power of ionizing laser, suggesting thatfurther increase can be expected as the laser system isimproved.
The characteristics of the low-energy muons were
measured by a 2-dimensional position sensitive MCP.
The observed beam proﬁle at the sample position
showed that the muons were tightly focused to a spotof 3 × 4 mm2 (FWHM), which is more than 100-foldsmaller than the size of the conventional surface muon
beam. The temporal width of the low-energy muon
was less than 10 nsec, which is 10-fold narrower thanthat of the surface muon beam. These results demonstrate that our method is ideally suited to pulsed muonsources, including the RIKEN-RAL muon facility.
A compact µSR spectrometer has been installed in
the beam line. A solenoid-type magnet can apply amagnetic ﬁeld of up to 700 Gauss at the sample position. Plastic scintillators cover around 80% of total
solid angle from the sample position, maximizing thepositron signal from low-energy muons. A GM refrig∗

High Energy Accelerator Research Organization (KEK)erator is mounted to the spectrometer, enabling thecooling ofa sample down to 10 K.
As a demonstration of the high time resolution of
the low-energy muon beam, we have implanted 15 keVmuons into SiO2 and observed the spin precession signal from triplet muonium in transverse magnetic ﬁeldsof 50 Gauss and 100 Gauss at room temperature. As
shown in Fig. 1, there was no observed reduction inasymmetry between the two measurements, which implies that higher frequencies of up to 30 MHz could beobserved without a loss of asymmetry.
For the ﬁrst application of this low-energy muon
beam, we are considering the measurement of the magnetic properties of a thin perovskite manganite ﬁlm
grown on SrTiO3 substrates. Perovskite manganites
show various interesting phenomena, such as colossal
magneto-resistance eﬀect, which have large potential
for device application. However, it is understood thatthe phase diagram of thin perovskite manganite ﬁlms
are diﬀerent from that of bulk crystals due to latticestrain from the substrates. The measurement of sucha system will be a good demonstration of the capability of low-energy muons as a unique probe of magnetic
properties for thin ﬁlms and multilayer systems.

Fig. 1. Muonium spin precession signal in SiO2 . The asymmetry is shown relative to the diamagnetic asymmetry
in bulk aluminium of 10.4(3)%.

References
1) P. Bakule et al.: Spectrochim. Acta B 58, 1019 (2003).
2) Y. Matsuda et al.: Physica B 326, 217 (2003).

149

RIKEN Accel. Prog. Rep. 39 (2006)

Particle discrimination using pulse shape analysis in Si detector
M. Kurokawa, H. Baba, M. Yamaguchi, S. Nishimura, T. Fukuchi,∗1 A. Ozawa,∗2 and Y. Tagishi
To identify the charge and mass numbers of nuclei,
the pulse-shape discrimination of a signal from a Si
detector was proposed more than 40 years ago. The
technique is based on a monotonic increase in chargecollection time with the charge and mass number ofnuclei having the same energy. The increase is associated with a longer distance between an electrodeon the junction side and the position where an incident particle induces ionization with the highest density. Collection time can be obtained by applying theappropriate analyzing method to a signal pulse froma detector. Since the idea was realized by Pauschet al.1) for the ﬁrst time, diﬀerent analyzing methods have been examined over these ten years to improve the capabilities of the technique. In spite ofthese eﬀorts, the discrimination in a low energy region
has been constrained because of an unexpected phenomenon. Shorter time information has been obtained
from the analyis for longer distance. To ﬁnd an analyzing method which can prevent the constraint, chargecollection time should be studied directly. Because thenormalized pulse height of the signal from a preampliﬁer is directly related to the position of the charge
carriers generated by the ionization, we recorded thepulse shape at the ouput stage of a preampliﬁer for
light-charged particles with low energy without performing any analysis.
Beam test was performed at the TANDEM accelerator at the University of Tsukuba. The incident energyof a 7 Li beam was 20 MeV, and scattered particles by
a C6 D4 target were detected using an ion-implanted
Si detector manufactured by Canberra. The speciﬁcations are shown in Table 1. The detector was operated
at the bias voltage required for the total depletion andwas irradiated from the ohmic side. The junction side
is divided into 4 strips. To record the pulse shape froma strip, the signal of the preampliﬁer was coded by asampling ADC (SIS3301) with a resolution of 14 bit
and 100 MSamples/s. The rise time of the preampliﬁer
was 75 ns for a signal from the strip with a capacitanceof 250 pF.
In Fig. 1, the energy dependence of the extracted
rise time, which is deﬁned here as the time diﬀerence
when the magunitude of the pulse reaches 15 and 60%
of its maximum height, is shown for the recorded pulse
shapes. The energy was obtained by trapezoidal shaping. As shown in the ﬁgure, charge discrimination ispossible down to a total energy of 3 MeV, which corresponds to the stopping range of 6 µm for a 7 Li ion.
This is the ﬁrst result for the ion with an energy lower
than 5 MeV showing the possibility of pulse shape discrimination. On the other hand, the present analysis
also shows the problem similar to that described previously. For He and Li ions below 8 MeV, rise timeis decreasing as a function of energy and each locus
merges below 3 MeV.
The present results show that the rise time does notseem to depend on atomic number in such a low energy
region. An attempt to extract a timing corresponding
to the starting point of the signal is now in progress.

Fig. 1. Relationship between energy and rise time (see inthe text).
Table 1. Speciﬁcations of detector used in this study.
type
n

∗1
∗2

150

eﬀective area
mm2
50 × 50

thicknessµm
320depletion voltage
V
20

Department of Physics, Rikkyo University
Department of Physics, University of Tsukuba

Reference
1) G. Pausch et al.: IEEE Trans. Nucl. Sci. 43, 1097
(1996).

RIKEN Accel. Prog. Rep. 39 (2006)

Recent development of liquid hydrogen target
K. Tanaka, Y. Kondo,∗1 M. Tamaki,∗2 H. Suzuki,∗2 T. Nakabayashi,∗1 K. Kobayashi,∗3 Y. Yanagisawa,
T. Minemura,∗4 H. Ryuto, T. Motobayashi, and H. Sakurai
A liquid hydrogen target1) has used in several experiments.2) In recent years, we have improved it for
application in a reaction cross-section (σR ) measurement. The main goal is to make the 30 mm thicknessof the liquid hydrogen target within 1% error, because
the accuracy of the target thickness directly reﬂects
that of σR . To achieve this goal, we have tried to precisely control target thickness and the temperature of
the liquid hydrogen target, because the density of aliquid depends on temperature.
The target cell consists of an aluminum frame anda thin beam window where a beam from an accelerator passes through. This window ﬁlm is swelled by apressure diﬀerence between a vacuum outside the celland the gas or liquid inside. To reduce the thickness
error, it is important to lower and control the swellingheight of the cell window. Therefore, we employed aHavar-alloy foil as the window for which the tensile
strength is very heigh. In the past, we used a Kaptonresin ﬁlm for the beam window. However, it easily expanded, thus, the swelling height became large and therepeatability of the height was not reliable. However,
the wrinkle on the Havar window ﬁlm increased theswelling height when the cell was ﬁlled with hydrogengas, therefore, we tried to remove it.
The Havar foil was easy to peel at the cryogenic temperature, because the thermal shrinkage due to thelower temperature between a metal and an adhesive
agent of a resinous matter is large, although we utilized
the Stycast 1266A Epoxy adhesive agent for which thethermal shrinkage is small. On the other hand, thethermal changes of the Kapton-resin ﬁlm and Epoxy
adhesive agent are similar, thus, the Kapton window
was stable against the temperature change. Therefore,
we glued the ring of the Kapton ﬁrm on the boundary
between the Havar foil and the aluminum frame of thecell to strengthen the stability of the gluing. The improved cell was tolerant under 2 atm pressure against
a vacuum and was stagle for many times phase transitions of the liquid hydrogen.
The wrinkles on the window mainly occurred after
heating the adhesive agent up to 93 degree as a second
stiﬀening to strengthen the stability of the glued Havar
window. With the Kapton-ring method, the adhesive
power was suﬃciently strong to make a liquid hydrogentarget without the second stiﬀening. Therefore, we
omitted the heating for the second stiﬀening to reduce
∗1
∗2
∗3
∗4

Department of Physics, Tokyo Institute of Technology
Department of Physics, University of Tokyo
Department of Physics, University of Saitama
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)

the wrinkles. A typical window is shown in Fig. 1.
We measured the shape of the window under several conditions. The distance between the sensor
and the surfaces of the beam window and the cell
frame was measured using the Laser displacement sensor KEYENCE LK-500 within 0.1 mm accuracy, andscanned in the horizontal and vertical directions fromthe target center. Table 1 shows the results of theswelling height at the center of the beam window. The
error in Havar window height is 0.1 mm. The typicalwindow swelling is shown in Fig. 2.
Temperature control is also important to deduce thethickness of the liquid hydrogen target because thedensity of a liquid depends on temperature. In thecase of liquid hydrogen, the density changes 1% per
0.6 K temperature change.3) We used the Si diode thermometer SCIENTIFIC INSTRUMENTS Si410AA inwhich the accuracy is within 0.1 K. The sensor output was read using the LAKESHORE 331S Temperature Controller, which controls the heater current automatically with proportional-integral-derivative control
loops based on the user-set temperature and feedback

Fig. 1. Typical window parts of target cell. The Havar
window is strengthened by the glued Kapton-ring ﬁlm
so as not to peel oﬀ after a large temperature change.

Table 1. Swelling height of target cell window. The Havar
window was measured at 16 K and the Kapton windowat room temperature.
windowmaterialpressuresize
1.0 atm 0.5 atm 0.3 atm
30 φ
Kapton 50 µm 2.5∼3 mm
30 φ
40 φ

Havar 12 µm
Havar 12 µm

0.9 mm
1.2 mm

0.8 mm
0.7 mm151

from the sensor. The stability of the liquid hydrogentemperature with the heater control was less than 0.1 K
per day.
We made the liquid hydrogen cell with the Havar
window. The swelling height of the window was lower
than that of the former cell using the Kapton window.
Furthermore, we installed the temperature control system which adjusted the heater current to reduce theﬂuctuation in liquid hydrogen density depending on
the temperature. With these improvements in the window swelling and the density of the liquid hydrogen,we could make the liquid hydrogen target within 1%
accuracy of thickness for σR measurement.
References
Fig. 2. Typical result of distance measurement. The horizontal axis shows the position along the window. The
vertical axis shows the height from the surface of which
the window adhered. The shaded area denotes the aluminum frame of the cell. This is the case for a 12 µmthick Havar window, 0.5 atm pressure, and a 30 φ size
window.

1521) H. Akiyoshi et al.: RIKEN Accel. Prog. Rep. 32, 167(1999).
2) Y. Yanagisawa et al.: Phys. Lett. B 566, 84, (2003); S.
Kanno et al.: RIKEN Accel. Prog. Rep. 38, 66 (2005).
3) B. A. Younglove et al.: J. Phys. Chem. Ref. Data 11, 1(1982); Webpage of National Institute of Standards andTechnology, http://webbook.nist.gov/chemistry/ﬂuid/

RIKEN Accel. Prog. Rep. 39 (2006)

Development of Self-Confining Radioactive Ion Target (SCRIT)
M. Wakasugi, T. Emoto, Y. Furukawa,∗1 S. Ito, T. Koseki, K. Kurita,∗2 T. Masuda,∗2 M. Nakamura, T. Suda,
T. Tamae,∗1 H. Takeda, and Y. Yano
The self-conﬁning radioactive ion target (SCRIT)
technology provides a ﬁxed RI ion target for electron scattering experiment. The RI ions are threedimensionally conﬁned along the electron beam axis in
the storage ring. This conﬁnement is realized by periodic transverse focusing kicks by the electron bunches
and additionally applied longitudinal mirror potential
at a local position of the electron storage ring. Since
the SCRIT is a completely new device, we should study
its performance. First we performed a computer simulation on the ion motion in the SCRIT. The resultsof this calculation indicate that the time-averaged luminosity of more than 1027 cm−2 s−1 is achievable.1)
The R&D study to conﬁrm the SCRIT principal
is now under way at the KSR in Kyoto University.
A prototype of the SCRIT devices is installed in the
KSR,2) as shown in Fig. 1. The prototype consists of
the SCRIT device, an ion source, and an electrostatictransport line for ion injection. The surface ionization
ion source of 133 Cs is used and the pulsed ion beam isgenerated by grid action. The ion beam is accelerated
to 10 keV and merged with the electron beam axis by
the 90-degree deﬂector. The SCRIT is an electrodesystem in which 40 thin electrodes are stacked every
11 mm to produce a longitudinal mirror potential. The
potential wall is quickly switched oﬀ and its timing is
synchronized with the ion injection.
Trapping of the 133 Cs ions in the SCRIT was conﬁrmed by measuring of the ions released from the
SCRIT at a certain trapping time after the injection.

Released ions go back along the injection line andsome of them is detected at the return ion detector.
Taking transmission eﬃciency and the estimated average charge state into account, the number of Cs ionstrapped in the SCRIT is obtained and then plotted as afunction of the trapping time in Fig. 2. The four seriesplotted in this ﬁgure have diﬀerent number of initiallyinjected ions (Ninj ). With a large Ninj , the numberof trapped ions is more quickly decreased. This phenomenon is expected from the calculation.1) Assuming that the ions exist transversely inside the electron
beam envelope in the SCRIT, the luminosity can becalculated to be L ∼ 1024 cm−2 s−1 in the trappingtime region of 0.1–1 s, L ∼ 1025 cm−2 s−1 in 10–100 ms,
and L ∼ 1026 cm−2 s−1 in 1–10 ms.
In the next step, we are preparing the direct determination of the luminosity by measurements of thebremsstrahlung X-ray or foreword-scattering electrons
produced by collisions with Cs ions.

Fig. 2. Observed number of trapped ions as a function of
the trapping time.

References

Fig. 1. SCRIT prototype installed in the KSR.

∗1∗21) M. Wakasugi, T. Suda, and Y. Yano: Nucl. Instrum.
Methods Phys. Res. A 532, 216 (2004).
2) A. Noda et al.: Proc. 5th Int. Conf. of European Particle Accelerator Conference, Barcelona, Spain, 1996-6,(Institute of Physics Publishing, Bristol and Philadelphia, 1996), p. 451.

Laboratory of Nuclear Science, Tohoku University
Department of Physics, Rikkyo University

153

RIKEN Accel. Prog. Rep. 39 (2006)

High-stability current source for EDM experiments
A. Yoshimi, K. Asahi, M. Uchida,∗ S. Oshima,∗ and T. Inoue∗
The measurement of spin precession is sometimes
very important for fundamental physics studies suchas the search for T-violating electric dipole moment(EDM). The developments of polarized 129 Xe nuclei
and the self-sustained nuclear spin maser with thepolarized nuclei are in progress aiming at the EDM
search.1) In such experiments, a magnetic ﬁeld with agood homogeneity and stability is required. The ﬂuctuation of the applied magnetic ﬁeld B0 should be as
small as possible because the precession frequency ofspin is proportional to B0 . A precise magnetometerwith magneto-optical rotation eﬀect is being developed
for actively stabilizing the magnetic ﬁeld.2) In this report, ﬁeld ﬂuctuation due to a current source which
provides a current in a solenoid magnet is discussed.
We have compared the stabilities of two current
sources. One is a conventional constant current source(1 A/10 V, minimum range is 1 µA) which we had used
for the spin precession measurements. This is commercially available, and its nominal stability is less than
10−3 . Another is a low-noise current source, PSE-1101,
which has been fabricated to reduce current ﬂuctuation
for a long-term period (low-frequency noise). The latter has a maximum current of 30 mA (30 mA/10 V).
The general cause of low-frequency noise for commercial current source comes from Zener diode used as a
voltage reference.3) A low-noise battery is used insteadas the voltage reference in the PSE-1101. The currents
were measured using the setup shown in Fig. 1, where
the currents in a solenoid magnet were measured using a precise ammeter DMM-2002, KEITHLEY. The

supplied current was set around 3.5 mA, which corresponds to a static ﬁeld of 2.8 µT.
The results are shown in Fig. 2. Figure 2 (a) shows
a comparison of the current stabilities of each current
source. The ﬂuctuation at a time scale of 103 seconds is greatly reduced, and it is estimated to be reduced by less than 1/30 as shown in Fig. 2 (b). In
Fig. 2 (b), data points were averaged every 60 seconds.
Thus, this ﬂuctuation width is smaller than the ammeter’s resolution, and is expected to be further reduced (δI/I < 10−6 ). Further stabilization is expectedby improving the thermal shield in the circuit. We
are now preparing for the frequency measurement of
the spin maser which can reveal current stability withhigher precision.

Fig. 2. Measured fluctuations of currents in solenoid magnet. (a) Comparison of stabilities when we use conventional constant current source and low-noise current
source PSE-1101 with low-noise battery. (b) Magnified
figure (along current axis) for data with PSE-1101.

References

Fig. 1. Setup for measuring current stability in solenoid
magnet. Solenoid magnet consists of two layers.

∗

154

Department of Physics, Tokyo Institute of Technology

1) A. Yoshimi et al.: RIKEN Accel. Prog. Rep. 36, 173(2003).
2) A. Yoshimi et al.: RIKEN Accel. Prog. Rep. 38, 169(2005).
3) C. Ciofi et al.: IEEE Trans. Instrum. Meas. 47, 78(1998).

RIKEN Accel. Prog. Rep. 39 (2006)

RF cavity for spin selection in RIABR
D. Nagae,∗1 K. Asahi,∗1 K. Shimada,∗1 A. Yoshimi, H. Ueno, T. Haseyama, J. Murata,∗2 Y. Kobayashi,
D. Kameda, M. Uchida,∗1 G. Kijima,∗1 T. Arai,∗1 M. Takemura,∗1 H. Kawamura,∗2
S. Suda,∗1 T. Inoue,∗1 and K. Takase∗1
A device that produces a low-energy and largely
spin-polarized RI beam based on the atomic beam resonance method (RIABR) has been developed.1,2) In
the RIABR method, the produced RI beam is ﬁrstly
decelerated and neutralized. RI atoms are then transmitted to a set of hexapole magnets to converge only
those atoms with a selected atom spin direction. An rf
ﬁeld at a certain frequency is applied, and according
to the Breit-Rabi scheme, a transition is induced when
the frequency satisﬁes a resonance condition. The
atoms then enter the region of the quadrupole magnets
where only those atoms that have executed the transition are deﬂected. Thus, a highly spin-polarized slow
RI beam is obtained. In the present study, we havefabricated a hyperﬁne transition system using 7 Li and
we are testing its performance.
The ground and the ﬁrst excited atomic levels of 7 Li
are split into total spin states F = 2 and F = 1 by
the hyperﬁne interaction. In our system, atoms in thestate of 2 S1/2 , F = 1 are optically pumped into 2 P1/2 ,F = 2 states (D1 transition) by a linearly polarizedlaser beam upstream an rf cavity. Because the traverse time of the atomic beam across the laser beam isapproximately 100 times as large as the spontaneousemission lifetime, the laser beam exceeding the saturation intensity strongly populates the hyperﬁne state2
S1/2 , F = 2. Fluorescence is detected by a photodiode(Hamamatsu S2281). The rf cavity is placed following
the pumping region to induce a hyperﬁne transition2
S1/2 , F = 2 → 2 S1/2 , F = 1 by applying an rf ﬁeld of
hyperﬁne frequency (803 MHz). A linearly polarizedlaser beam downstream the rf cavity induces the D1
transition only for atoms that have executed the hyperﬁne transition in the rf cavity and ﬂuorescence is
detected by an another photodiode.
A schematic view of the test experiment setup is
shown in Fig. 1. An atomic beam was produced byheating lithium metal in an oven at 500◦ C. Lithium
atoms were extracted through a 1 mm oriﬁce of theoven. The oven and the atomic beam path were enclosed in a vacuum chamber. The pressure was approximately 2×10−5 Torr. The lithium atoms were excitedusing a single-frequency diode laser with a customdesigned external cavity. The typical power was 15mW at 670.97 nm. The linewidth of the laser was
suﬃciently narrow to distinguish two hyperﬁne transitions. We detuned the laser frequency up to 5.2 GHz bysweeping the grating angle with a piezoelectric trans∗1∗2

Fig. 1. Schematic view of RF test cavity.

ducer. As shown in Fig. 2, a ﬂuorescence spectrumwith three peaks was obtained using the upstream photodiode. The ﬁrst peak corresponds to the 6 Li D2 line.
The second and third peaks correspond to the transitions 2 S1/2 , F = 2 → 2 P1/2 and 2 S1/2 , F = 1 → 2 P1/2
hyperﬁne lines of 7 Li, respectively, separated by about
800 MHz. The resonance widths were predominantly
determined by the Doppler broadening due to beam divergence. The hyperﬁne splittings of the excited states
were not resolved due to the Doppler broadening.
A measurement of the spin transition will be performed soon.

Fig. 2. Fluorescence taken during laser detuning. The firstpeak corresponds to the 6 Li D2 line and the second andthird peaks to the 7 Li D1 lines.

References
1) D. Nagae et al.: Physica E 29, 580 (2005).
2) K. Shimada et al.: RIKEN Accel. Prog. Rep. 39, 156(2006).

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

155

RIKEN Accel. Prog. Rep. 39 (2006)

Development of gas degrader and gas scintillation beam monitor
K. Shimada,∗1 K. Asahi, D. Nagae,∗1 A. Yoshimi, H. Ueno, Y. Kobayashi, T. Haseyama, J. Murata,∗2
M. Uchida,∗1 D. Kameda,∗1 G. Kijima,∗1 H. Kawamura,∗2 T. Arai,∗1 M. Takemura,∗1
S. Suda,∗1 T. Inoue,∗1 K. Takase,∗1 and H. Miyoshi∗1
We have developed a method of a producing slow
radioactive isotope (RI) beam for the RI atomic beam
resonance method (RIABR).1) In this paper, we reporton the development of an energy degrader that is to be
used when the beam is stopped in a gas to produce aslow RI beam. In addition, it can be useful for monitoring the incoming beam intensity on the basis of thescintillation of Ar atoms excited by the incident beam.
When a beam is stopped at an arbitrary position
in a gas-ﬁlled chamber, the beam is passed throughsome material to reduce its energy. Very ﬁne controlof the thickness of the material for energy reduction isrequired because of the limited stopping power of thegas. Earlier, we had been using Al foil whose angle tothe beam axis could be controlled in order to change
the thickness of the energy degrader.2) For ﬁner thickness control, we tried another approach of using on Ar
gas volume as the energy degrader, since the densityof the gas is extremely smaller than that of the solid.
On the other hand, when a charged particle passes
through a volume of Ar gas, it leaves a populationof excited Ar atoms in its wake. When these excited
Ar atoms return to their ground state, photons are
emitted. The number of excitated Ar atoms is proportional to the incident beam intensity. Therefore, thebeam intensity can be estimated by counting the emitted photons. The main wavelength of scintillation isaround 250 nm.3) The emitted scintillation photons aredetected by a UV photomultiplier tube (Hamamatsu
R2809U-06), which is sensitive to wavelengths between
160 and 320 nm.
Test experiments of the gas degrader and the beam
monitor were carried out at Tohoku University Cyclotron and Radioisotope Center (CYRIC) (Fig. 1).
The incident beam was 14 N5+ of 130 MeV. The pressure of Ar gas was controlled by a mass ﬂow controller(MKS M100B) and a needle valve located between thechamber and a scroll pump. The accuracy of the pressure was typically ±0.1 Torr at 218.0 Torr, which corresponded to ±1.4 × 10−5 g/cm2 . A Faraday cap (F. C.)with 60 mm i.d. was placed at 220 mm from the Al win-

dow. The two grounded electrodes were attached tothe inside wall of the duct to quench the space charge
generated far from the F. C. by collisions between the
beam and Ne atoms. The currents at the F. C. were
not the same as the beam current because the remaining space charge was added, which is typically 40 times
larger than the beam current.
The currents at the F. C. against the pressure of
the Ar are shown in Fig. 2. The curves of the current
should be constant until the thickness of the degrader
becomes comparable to the range of the particle, however, they increase with increasing intensity. One of
the reasons behind this is the secoundary electron
emission eﬀect. On the other hand, each decreasing
part of the curves is ﬁtted with a Woods-Saxon curve.
When the glass chamber was a vacuum, the mean pressure was 302 Torr and the width was 0.66%, whichcorresponds to 39.7(9) mg/cm2 . Meanwhile, when theglass chamber was ﬁlled with 180 Torr Ne gas, themean pressure was 266 Torr and the width was 1.0%,
which corresponds to 34.9(6) mg/cm2 . Therefore wecan make the incident beam stop in the Ne gas volume by adjusting the Ar pressure to between 266 Torrand 302 Torr. Figure 3 shows a plot of the scintillation
current vs. the incident beam current. It shows good
linearity. So far, the accurary of the beam current isevaluated to be 10% but is making limited by the calibration process. The incident beam current read by
the F. C. ﬂuctuated due to the improper shape of theF. C.

Fig. 2. Normalized current
at Faraday Cup as afunction of Ar gas pressure.

Fig. 3. Currents at theUV multiplier tube
and F. C. were changing beam intensity.

References

Fig. 1. Setup of the experiments.
∗1
∗2

156

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

1) K. Shimada et al.: RIKEN Accel. Prog. Rep. 38, 163(2005).
2) H. Miyoshi et al.: RIKEN Accel. Prog. Rep. 37, 171(2004).
3) G. F. Knoll: in Radiation Detection and Measurement(John Wiley & Sons, Inc., Hoboken, 2000), p. 246.

RIKEN Accel. Prog. Rep. 39 (2006)

Trapping radioactive Be isotopes using rf ion guide
A. Takamine,∗1 M. Wada, Y. Ishida, T. Nakamura, K. Okada,∗2 S. Shiba,∗3 Y. Yamazaki, T. Kambara,
Y. Kanai, T. M. Kojima, Y. Nakai, N. Oshima,∗4 A. Yoshida, T. Kubo, S. Ohtani,∗3 K. Noda,∗5
I. Katayama,∗6 G. Jegou, V. Lioubimov,∗7 H. A. Schuessler,∗7 V. Varentsov,∗8 and H. Wollnik∗9
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 at providing universal slow RI-beams
of high purity and small emittance by slowing down
and cooling energetic RI ions using an rf ion guide.
We achieved a high overall eﬃciency of ∼5% and amaximum intensity of ∼24 kcps for ∼100 MeV/nucleon
8
Li ions from the RIKEN projectile fragment separator
RIPS. Although the eﬃciency decreases as the beam
intensity increases, this is found to be due to the spacecharge produced during the stopping process of incoming energetic ions.3) Several hypotheses to overcome
the problem are proposed and they are to be tested
soon.
Because the present performance of the rf ion guideis already suﬃcient for performing a precise spectroscopy of the hyperﬁne structure of stored Be+ ionsin a trap, we connected a cryogenic linear Paul trap following the long SPIG as shown in Fig. 1. A schematic
diagram of the setup is also shown in Fig. 2.
In oﬀ-line tests, we used stable 9 Be+ ions, which areproduced by Nd:YAG laser ablation in the gas cell, to
optimize the trapping condition of Be ions. The ablated 9 Be ions are extracted from the gas cell throughthe exit nozzle. The 9 Be ions are transported by arf six-pole beam guide (SPIG)4) through diﬀerential

Fig. 2. Schematic of experimental setup. Refer to Refs. 1
and 3 for details. Ions thermalized in the gas cell ﬁlledwith 13 mbar of He are transported by dc ﬁelds andrf ﬁelds to the exit nozzle and transported by SPIG.1)
SPIG consists of two segments, an upstream sectionof 10 cm and a downstream section of 50 cm. These
two segments are applied rf voltages of 120 Vp.p. with
24 MHz and 120 Vp.p. with 20 MHz, respectively. The
frequency of the quadrupole mass ﬁlter is 3.36 MHz andthe mass resolving power is 22.

pumping sections into a high vacuum chamber. Because the beam transported from the gas cell contains
many impure molecular ions, we used a quadrupole
mass ﬁlter to select the ions of interest, and the selectedions were injected into the cryogenic linear Paul trap
where laser spectroscopy was performed. The selected
Be+ ions were continuously accumulated in the linear
Paul trap by buﬀer gas cooling. A schematic drawingof the linear trap and axial potential produced by theelectrodes are shown in Fig. 3. We measured the in-Fig. 1. Photo of experimental setup.
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8
∗9

Graduate School of Arts and Sciences, University of Tokyo
Department of Physics, Sophia University
Institute for Laser Science, University of ElectroCommunications
Research Institute of Instrumentation Frontier, Advanced
Industrial Science and Technology (AIST)
National Institute for Radiological Science
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Association (KEK)
Department of Physics, Texas A&M University, USA
Kholopin Radium Institute, Russia
II. Physikalisches Institute, Justus-Liebig-Universitaet, Germany

Fig. 3. Cryogenic linear Paul trap for laser spectroscopy.
The trap electrode is segmented into three sections.
Each 4-cm-long segment consists of four hyperbolicalelectrodes of r0 = 8 mm. A rf voltage of 250 Vp.p. with
3.7 MHz is applied to the trap, which radially conﬁnes
ions. The static potential as shown in this ﬁgure is also
applied, which axially conﬁnes ions.

157tensity of slow ion beams and the number of trappedions using a channeltron located behind the linear Paul
trap.
Figure 4 shows the number of trapped ions and trap-

ping eﬃciency as a function of trapping time. We
trapped 1.6 × 106 ions at maximum and achieved amaximum trapping eﬃciency of 43%. The kinetic
energy of ions transported was ∼6 eV, which is determined by the potential of the upstream SPIG.
The He gas pressure in the trap was approximately
6.0 × 10−3 mbar.
In an on-line experiment, we injected 100 MeV/
nucleon 10 Be beams provided by RIPS into our setup.
Although the intensity of slow 10 Be ions was as low
as 10 cps due to a problem in the SPIG, we succeededin trapping several hundreds 10 Be+ ions in the linear
trap and measured the isotope shift of 10 Be+ .5)
References

Fig. 4. The number of trapped ions and trapping eﬃciency
were plotted for diﬀerent trapping periods. The beam
intensity was 10 kcps.

1581) 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.: Rev. Sci. Instrum. 76, 103503(2005).
4) H. Xu et al.: Nucl. Instrum. Methods Phys. Res. A 333,
274 (1993).
5) T. Nakamura et al.: RIKEN Accel. Prog. Rep. 39, 41(2006).

RIKEN Accel. Prog. Rep. 39 (2006)

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). The major updates undertaken this year are
summarized as follows.
1) Replacement of LAN Hardware
The hardwares of the local area network (LAN) of
RIKEN Wako campus have been updated in April
2005. Concerning this update, all LAN equipmentsof RARF have also been updated to a new system.
Moreover, new LAN equipment has been installed in
the new buildings of RI Beam Factory (RIBF) accelerators and experiments in June 2005.
Figure 1 shows the current configuration of RARF/
RIBF network.
The new network equipment of
RARF/RIBF consists of Catalyst 4507R regionalrouters located at the Nishina and RIBF buildings andCatalyst 3750 floor switches located at each floor of thebuildings.
Each Catalyst 4507R router is equipped with a redundant dual control unit for reliable operation. The
Catalyst 4507R routers of the Nishina building are connected to Catalyst 6509 RIKEN Wako backbone routerby 8 pairs of optical fibers with bandwidth of 8 Gbps.
Moreover, the Catalyst 4507R routers of RIBF building are connected to the Catalyst 4507 router of the
Nishina building at 8 Gbps. The Catalyst 6509 backbone routes are connected to the Internet (Super Sinet)
via Inkra 1504 firewall at the speed of 1 Gbps. This
bandwidth of the Internet connection is expected to
be expanded from 1 to 10 Gbps in 2006.
The current RARF network consists of 26 private
networks and two global networks. Each private network is basically related to each research laboratory
or each floor of the buildings. The routing of IP andAppletalk between the private networks is carried out
for convenience.
All computers connected to the RARF private LAN

are assigned private addresses statically or dynamically. To access the Internet, these private addresses
are translated dynamically to global addresses by Inkra
1504 firewall. The utilization of the Virtual Private
Network (VPN) enables the access of private networks
from outside of RIKEN using secure encrypted channelover the Internet.
2) Wireless LAN Access point of RARF
Recently, most laptop computers have beenequipped with wireless network interface. This year, 35
units of wireless LAN access point of 802.11g/802.11b(54 Mbps/11 Mbps) standard have been installed in
RARF/RIBF LAN. Table 1 shows the summary of thenumber of wireless LAN access points in RARF/RIBF
area. The details of the RARF/RIBF wireless LAN
access points can be found elsewhere.2) Wi-Fi Protect
Access authentication is used for most wireless LAN
access points for establishing secure connections.
3) New 10 TB RAID File System
Currently 2.8 TB SCSI Redundant Arrays of Inexpensive Disks (RAIDs) are connected to RARFNFS0
file server and they are utilized as work area for experimental data analysis and simulation. However, morethan six years have passed since the installation andthe replacement of the SCSI RAID system is still requited for the sake of maintenance and security of thefile contents. We have installed a new 10 TB FiberChannel RAID to update this SCSI RAID system.
Moreover, the new file server of SUN Fire V40z withdual Opteron 880 CPU (dual core of 2.4 GHz) has been
installed to serve the 10 TB file systems.
Most of the RARF users have e-mail addresses ofthe following patterns:
username@rarf.riken.jp or username@riken.jp
The first represents the e-mail address of the RARF
mail server (RARFAXP) and the second represents thee-mail address of the RIKEN mail server (postman).
Table 1. Number of wireless access points (WAPs) of
RARF/RIBF.
Building
RIBF
Nishina
Linac
Mail Bldg.

Number of WAPs
36
14
3
3

References

Fig. 1. Configuration of RARF/RIBF network.

1) T. Ichihara et al.: RIKEN Accel. Prog. Rep. 36, 199(2002).
2) http://rarfaxp.riken.jp/comp/net/wireless.html

159

RIKEN Accel. Prog. Rep. 39 (2006)

Hydrogen depth profile analysis of silicone modified byplasma ion implantation
T. Kobayashi, T. Yokota,∗ A. Nakao, and K. Ogiwara
Medical catheters are made of biologically inert
materials such as silicone, polytetra-ﬂuoroethylene(PTFE) and polyurethane. Due to their poor tissueadhesion, the interface of the catheter and the tissue tends to be a path for bacteria when it is set inplace for a long period.1) If the tissue adheres wellto the catheter surface, exit-site and tunnel infections
will be suppressed. We irradiated silicone sheets andtubes with inert gas ions by plasma-based ion implantation (PBII). The cell attachment and the adhesion
strength of the ﬁbrin glue (biological tissue adhesive)
were markedly improved.2) In this study, depth proﬁlesof elements at the surface of irradiated silicones were
investigated by Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA)
using a pelletron accelerator.
Silicone sheets (THE740-8U, 1 mm thick, GE
Toshiba Silicones) and tubes (catheters for peritoneal
dialysis, 4 mmφ × 1 mm thick, Medionics InternationalInc.) were irradiated with Ar ions by PBII for 30 minutes at a pressure 1 × 10−1 Pa. PBII was performed byapplying a pulsed RF (13.56 MHz, 500 W, 30 µs) and apulsed DC (from 0 to –10 kV, 10 µs) alternately to theelectrically ﬂoated sample holder at a cycle of 2 kHz.
The sheet samples were ﬁxed with a conductive adhesive tape on the ﬂat sample holder. The tubular samples were penetrated with bar-type holders and only
the outside was irradiated. During irradiation, thetemperature of the sample surface was not observed;
however, the temperature on the rear side of the specimens below 95◦ C was observed using a sticker-typetemperature indicator. After irradiation, the samples
were cooled in vacuum for 60 minutes.
Figure 1 shows the RBS spectra of silicones obtained using a 2.28 MeV He+ beam. The distributionof the implanted Ar atoms became broad with increasing voltage. Using HYPRA simulation code, the mean
range of Ar atoms was estimated to be less than 6.5 nm
for 5 kV and 6.5–19.5 nm for 10 kV. The broad peak observed around 340 ch corresponds to Fe atoms from thechamber or the electrode made of stainless steel. In ourcase, the distance between the sample holder and thechamber wall is about 20 cm. The size and material ofa chamber, an electrode and sample holders should be
carefully designed to avoid unexpected contamination.
Enrichment of carbon atoms due to a gas detachment
is clearly observed in the sample irradiated with 10 kV.
The deposition of amorphous carbon will also occur byattracting emitted hydrocarbon.
Figure 2 shows the ERDA spectra obtained using∗

Fig. 1. RBS spectra of silicone specimens irradiated withAr by PBII.

Fig. 2. ERDA spectra of silicone specimens irradiated withAr by PBII.

the 2.28 MeV He+ beam at an incident angle of 15◦
with respect to the surface. The hydrogen distribution is estimated by comparing each spectrum withthe unirradiated one. At the surface, hydrogen atoms
detached due to a bond scission caused by incident ionsand thermal decomposition. On the other hand, thehydrogen density increased in the interior region. This
is not observed in conventional ion implantation using
accelerators. The detached hydrogen in plasma will be
accelerated and implanted again.
The thus-formed carbon-rich surface showed good
aﬃnity with cells and proteins and a test using animals
has been started.
References
1) W. F. Kean, S. R. Alexander, and G. R. Balite: Perit.
Dial. Int. 16, 557 (1996).
2) T. Kobayashi et al.: submitted to Surf. Coat. Technol.

School of Engineering, University of Tokyo

161

RIKEN Accel. Prog. Rep. 39 (2006)

QT resummation in transversely polarized Drell-Yan process
H. Kawamura, J. Kodaira,∗1 H. Shimizu,∗1 and K. Tanaka∗2
Transversely polarized Drell-Yan process (tDY) is
one of the processes where we can measure thetransversity distribution δq(x), the distribution oftransversely polarized quarks inside transversely polarized nucleon. δq(x) can not be measured in inclusive
DIS due to its chiral-odd nature,1) and remains as thelast unknown distribution at the leading twist.
The spin dependent part of tDY cross section is proportional to cos(2φ) where φ is the azimuthal angle ofthe produced lepton. Therefore the calculation of QCD
corrections to this process is cumbersome comparedwith unpolarized and longitudinally polarized cases.
So far, QT -integrated cross section at O(αs ) has been
calculated by several authors in various schemes,2–4)
while QT distribution of the DY-pair is given by Vogelsang and Weber in massive gluon scheme only.3) Here
we present QT dependent cross section in M S scheme.
We consider O(αs ) corrections to tDY: h1 (P1 , s1 ) +h2 (P2 , s2 ) → l(k1 ) + ¯l(k2 ) + X, where h1 , h2 denote
nucleons with momentum P1 , P2 and transverse spin
s1 , s2 , and Q = k1 + k2 is the 4-momentum of DY pair.
The spin dependent cross section ∆T dσ ≡ (dσ(s1 , s2 )−dσ(s1 , −s2 ))/2 is given as a convolution
∆T dσ = dx1 dx2 δH(x1 , x2 ) ∆T dσ̂(s1 , s2 ), (1)where δH(x1 , x2 ) = i e2i [δqi (x1 )δ q̄i (x2 ) + (1 ↔ 2)]and ∆T dσ̂ is the corresponding partonic cross section.
We compute the one-loop corrections to ∆T dσ̂, which
involve the virtual gluon corrections and the real gluon
emission contributions, e.g., q(p1 , s1 ) + q̄(p2 , s2 ) →l(k1 ) + l̄(k2 ) + g, with pi = xi Pi . We regularize the infrared divergence in D = 4−2 dimension, and employ
naive anticommuting γ5 which is a usual prescription
in the transverse spin channel.4) In the MS scheme, we
eventually get to NLO accuracy,∆T dσ
2dQ dQ2T dydφ
= N cos (2φ) X(Q2 , Q2T , y) + Y (Q2 , Q2T , y) , (2)where N = α2 /(3 Nc S Q2 ) with S = (P1 + P2 )2 , y is
the rapidity of virtual photon, and φ is the azimuthal
angle of one of the leptons with respect to the initial spin axis. The cross section is decomposed into
two parts. The function X contains singular terms:
δ(Q2T ), 1/(Q2T )+ , (ln(Q2 /Q2T )/Q2T )+ , etc., while Y is ﬁnite at QT = 0. The analytic expressions of X and Y
can be seen in Ref. 5.
∗1∗2

As is well-known, the singular terms αn lnm (Q2 /Q2T )/ Q2T (m ≤ 2n − 1) appear at each order of αs
due to the soft gluon eﬀects, and resummation of theselogarithmic terms are needed to obtain a reliable preFigure 1 shows the QT
diction of QT distribution.
√
distribution of tDY at S = 100 GeV, Q = 10 GeV,y = φ = 0 with a model for δq(x) given by Martin et al.6) We implement the integration in impact
parameter space7) by “contour deformation prescription”.8) We also take the non-perturbative function as
F N P (b) = exp(−gb2 ) where b is the impact parameterconjugate to QT . Solid line shows the O(α∫ ) result,while the dashed and dot-dashed lines show the resummed results at the next to leading log (NLL) level,with g = 0.5 GeV2 and g = 0, respectively.

Fig. 1. QT distribution: ∆T dσ/dQ2 dQT dydφ at
100 GeV, Q = 10 GeV, y = φ = 0.

√

S =References
1) J. P. Ralston and D. Soper: Nucl. Phys. B 152, 109(1979).
2) A. Mukherjee, M. Stratmann, and W. Vogelsang: Phys.
Rev. D 67, 114006 (2003), and references therein.
3) W. Vogelsang and A. Weber: Phys. Rev. D 48, 2073
(1993).
4) W. Vogelsang: Phys. Rev. D 57, 1886 (1998).
5) H. Kawamura et al.: Nucl. Phys. B (Proc. Suppl.) 135,
19 (2004); H. Kawamura, J. Kodaira, H. Shimizu, andK. Tanaka: hep-ph/0512137.
6) O. Martin et al.: Phys. Rev. D 57, 3084 (1998); Phys.
Rev. D 60, 117502 (1999).
7) J. C. Collins, D. Soper, and G. Sterman: Nucl. Phys. B
250, 199 (1985).
8) S. Kulesza, G. Sterman, and W. Vogelsang: Phys. Rev.
D 66, 014001 (2002).

Theory Division, High Energy Accelerator Organization(KEK)
Department of Physics, Juntendo University

163

RIKEN Accel. Prog. Rep. 39 (2006)

Soft-gluon resummation for prompt photons†
W. Vogelsang
Prompt-photon production at high transverse momentum, pp, pp̄, pN → γX, has been a classic tool for
constraining the nucleon’s gluon density, because atleading order a photon can be produced in the Compton reaction qg → γq. The “point-like” coupling of thephoton to the quark provides a potentially clean electromagnetic probe of QCD hard scattering. However,a pattern of disagreement between theoretical next-toleading order (NLO) predictions1,2) and experimental
data in the ﬁxed-target regime3,4) has been observedin recent years, NLO theory showing a shortfall.
In a recent paper,5) we have shown that the theoretical description of single-inclusive photon production in the ﬁxed-target regime is improved by taking
into account large perturbative contributions to thepartonic hard-scattering cross sections to all orders in
perturbation theory. These terms, known as thresholdlogarithms, arise when the initial partons have justenough energy to produce a high-transverse momentum photon and a massless recoiling jet. The phasespace available for gluon radiation vanishes then, resulting in large logarithmic corrections to the partonic
cross section. For the cross section integrated over all
rapidities, the most important logarithms are of theform αsk ln2k 1 − x̂2T at the kth order in perturbation√
theory, where x̂T ≡ 2pT√/ ŝ, with pT the photon transverse momentum and ŝ the partonic center-of-massenergy. Suﬃciently close to threshold, NLO, which
captures only the term for k = 1, will not be adequate,
and all logarithmic terms will become relevant.5)
High-pT photons are not only produced by the“direct” contributions from the partonic hard processes ab → γc, but also in jet fragmentation. Despite the fact that according to the NLO calculation
this fragmentation contribution is only a subdominantpart of the cross section, it receives larger thresholdcorrections, due to the structure of the underlying
hard-scattering cross sections.6) Figure 1 shows theratios direct/(direct+fragmentation) and fragmentation/(direct+fragmentation) as functions of the√photon transverse momentum pT , for pp collisions at S =31.5 GeV. One can see that the NLO fragmentation
component contributes about 40% of the cross section
at the lowest pT shown and then rapidly decreases,
becoming lower than 10% at pT ≈ 11 GeV. After resummation, however, the fragmentation contribution
yields almost 60% of the cross section at smaller pT
and still more than 20% at pT = 11 GeV.
Figure 2 shows a comparison
with the data for√
pp → γX from UA64) at S = 24.3 GeV. The resummed calculation, which shows a very small scale†

164

Condensed from the article Phys. Rev. D 72, 014014 (2005)

Fig. 1. Relative contributions of direct and fragmentation√
photons to the cross section for pp collisions at S =31.5 GeV.

Fig.√2. Comparison to data from UA64) for pp → γX at
S = 24.3 GeV and photon rapidities −0.2 ≤ η ≤ 1.

dependence, is in very good agreement with the data.
Resummation of the fragmentation component leads
to a non-negligible enhancement of the cross section.
References
1) P. Aurenche et al.: Phys. Lett. B 140, 87 (1984); Nucl.
Phys. B 297, 661 (1988); H. Baer et al.: Phys. Lett. B
234, 127 (1990); Phys. Rev. D 42, 61 (1990); L. E.
Gordon and W. Vogelsang: Phys. Rev. D 48, 3136
(1993); Phys. Rev. D 50, 1901 (1994).
2) F. Aversa et al.: Nucl. Phys. B 327, 105 (1989); D. de
Florian: Phys. Rev. D 67, 054004 (2003); B. Jäger etal.: Phys. Rev. D 67, 054005 (2003).
3) L. Apanasevich, E706 Collaboration et al.: Phys. Rev.
Lett. 81, 2642 (1998); Phys. Rev. D 70, 092009 (2004).
4) G. Ballocchi, UA6 Collaboration et al.: Phys. Lett. B
436, 222 (1998).
5) D. de Florian and W. Vogelsang: Phys. Rev. D 72,
014014 (2005).
6) D. de Florian and W. Vogelsang: Phys. Rev. D 71,
114004 (2005).

RIKEN Accel. Prog. Rep. 39 (2006)

Thermal phase transition of color superconductivity with
Ginzburg-Landau action on the lattice
M. Ohtani, S. Digal,∗ and T. Hatsuda∗
In dense cold quark matter, the color-superconducting
phase is expected to be realized due to diquark pairing. Since the most attractive channel is found to bein the color anti-triplet and J P = 0+ , the diquark ﬁeld
in this channel, Φcf , is most relevant for color superconductivity. A three-dimensional Ginzburg-Landau(GL) action written in terms of Φcf was proposed1) tostudy the thermal transition of color superconductivity. It was realized that thermal gluons convert thesecond-order transition in the mean-ﬁeld theory to theﬁrst-order transition.2,3) Such a weak-coupling study,
however, is valid only at an extremely high density.
Furthermore, thermal ﬂuctuations in Φcf become crucial as density decreases.2)
Motivated by this, we carry out Monte-Carlo simulations of the GL action.4) In our simulation, we extend
the GL action1) to a four-dimensional action to deﬁnethe Polyakov loop. The discretization of the extended
action and rescaling of the ﬁelds lead us to the action2 
S = x Tr(Φ†x Φx ) + (λ1 + λ2 ) Tr(Φ†x Φx ) − 1
2 +λ2 Tr(Φ†x Φx )2 − Tr(Φ†x Φx )
−2κ µ Re Tr(Φ†x+µ Uµ∗ Φx ) + Sg ,(1)
where Sg is the standard plaquette action. Taking several sets of λi , we carry out simulations by scanning κwith a lattice volume of 2 × 123 . We use the pseudo
heat-bath method to update link variables and generalize the update algorithm of SU(2) Higgs.
The color-superconducting and normal phasesareby the gauge invariant operator
 distinguished
†
Tr
Φ
Φ
.
We
can
observe a discontinuous changex x
x
in expectation value with κ. We conﬁrm the discontinuity of other gauge-invariant operators at the sameκ. This is evidence of the ﬁrst-order phase transition.
Moreover, we can diﬀerentiate diﬀerent † colorsuperconducting states by diagonalizingx Φx Φx in
the ﬂavor space to extract its eigenvalues. We observe
one large and two degenerate small eigenvalues in aparticular set of couplings. In this case, we regard
the state as the 2SC phase in which the quarks pairin one speciﬁc color-ﬂavor channel. We also observe
three degenerate eigenvalues, which correspond to the
CFL phase where all channels are involved equally inthe pairing. As wescan κ, we ﬁnd rapid changes inthe eigenvalues of x Φ†x Φx at κc . When we simulate
around this point, we observe the hysteresis loops ofthe observables. This is also evidence of the ﬁrst-ordertransition.
∗

Department of Physics, University of Tokyo

To determine the most stable state near the critical point, we divide the lattice volume into domains
and place diﬀerent phases of the hysteresis loop into
diﬀerent domains. Starting from such a mixed conﬁguration, a state with the highest pressure pushes away
the other states after many update steps. In this way,
we can determine the most favorable state for each κ.
We ﬁnd three types of transition depending on thevalue of couplings as shown in Fig. 1: for large λ2 ,a transition from the normal phase to CFL occurs.
For small or negative λ2 , a transition from the normal
phase to 2SC occurs. For intermediate λ2 , successive
transitions, normal→2SC→CFL, occur.
The global feature of the phase diagram in Fig. 1
is qualitatively similar to that of the weak-coupling
analysis. Note that, near the phase boundary between
2SC and CFL, we ﬁnd that metastable 2SC survives,
even when the global minimum of free energy transfers
directly from the normal phase to CFL.
To obtain a realistic phase diagram of color superconductivity on the temperature (T ) and chemical potential (µ) plane, it is necessary to relate our couplings
to T and µ. Quark masses and color and charge neutralities become crucial at a low baryon density andlead to a more complex phase structure. Further studies are needed to solve these problems.

Fig. 1. Phase diagram in coupling space obtained by simulation.

References
1) K. Iida and G. Baym: Phys. Rev. D 63, 074018 (2001);
Phys. Rev. D 66, 014015 (2002).
2) T. Matsuura, K. Iida, T. Hatsuda, and G. Baym: Phys.
Rev. D 69, 074012 (2004).
3) I. Giannakis, D. F. Hou, H. C. Ren, and D. H. Rischke:Phys. Rev. Lett. 93, 232301 (2004).
4) S. Digal, T. Hatsuda, and M. Ohtani: hep-lat/0511018.

165

RIKEN Accel. Prog. Rep. 39 (2006)

Magnetic vortex in color-flavor locked quark matter†
K. IidaThe possibility that dense quark matter occurs inneutron stars has been considered for the past three
decades. The possible presence of a diquark condensate in such quark matter has generated new interestin such matter. Among various condensates, a colorﬂavor locked (CFL) state,1) in which all three color andﬂavors are gapped, has been studied most intensively,
along with a two-ﬂavor pairing state. In the weak coupling (high density) and massless limit the CFL stateis most stable at zero temperature and near the transition temperature, a feature ensured by the quarkquark attraction in the color antitriplet channel due
to one-gluon exchange. Although the massless, weakcoupling results for diquark condensation are modiﬁedby eﬀects of strong coupling and nonzero quark masses
in a regime as might be encountered in possible quark
matter in neutron star interiors, the CFL phase has tobe reckoned with as a reference state in such a regime.
Response of the CFL condensate to magnetic ﬁelds,
as would be experienced by quark matter if present inneutron stars, was considered in Refs. 2–4. Becauseof nonvanishing color and electric charge carried bydiquark pairs, electromagnetic superconductivity andcolor superconductivity occur in the CFL phase. These
two phenomena are not independent in the sense thattransverse photon and gluon ﬁelds are mixed with eachother. One of the resultant mixed ﬁelds is freely propagating, while the other is Meissner screened and thus
massive. The massive mixed ﬁeld and the winding of
the SU (3) phase in color-ﬂavor space are essential to
the structure of a magnetic vortex in the CFL phase.
This point was not taken into account in Ref. 3. The
criterion of whether or not the CFL state can allow
magnetic vortices to form (type II or type I) has been
described by Giannakis and Ren4) in terms of the energy needed to form a planar surface separating thenormal and superconducting material, but the detailed
structure of the magnetic vortex has yet to be determined.
In this work we examine the properties of magnetic
vortices in the CFL phase within the framework ofGinzburg-Landau theory. These vortices are characterized by three diﬀerent ﬁelds: the CFL diquark ﬁeld,
the massive photon-gluon mixed ﬁeld, and a colorﬂavor unlocked diquark ﬁeld coupled to the mixed
ﬁeld.4) In the London limit where the wavelengths of
distortions of the condensate are long compared with†

166

Condensed from the article in Phys. Rev. D 71, 054011(2005)

the size of the vortex core, the supercurrents surrounding the core can be written in terms of the color-ﬂavor
SU (3) phase of the CFL condensate and the mixed
ﬁeld. From such supercurrent structures we derive thelower critical ﬁeld, Hc1 . We next examine the vortex structure near the core, in which the color-ﬂavor
unlocked condensate plays a role as shown in Fig. 1,
and derive the upper critical ﬁeld, Hc2 . Finally werevisit how to distinguish between type I and type IIsuperconductors from the viewpoint of the intervortex
interactions. We have found that the nature of theintervortex interaction, controlled by the color-ﬂavor
unlocked condensate, provides a stringent constraint
on the type II regime.

Fig. 1. Schematic variation of the massive photon-gluon
mixed field Bz8 (solid line), the CFL condensate (u +2v)/3 (dotted line), and the color-flavor unlocked con√densate 2(u − v)/ 3 (dashed line) for a singly quan√
tized vortex (λCFL > ξCFL > ξCFL with the London
penetration depth λCFL , the Ginzburg-Landau coherence length ξCFL , and the parameter  characterizing
the scale of the spatial variation of the color-flavor unlocked condensate).

References
1) M. Alford, K. Rajagopal, and F. Wilczek: Nucl. Phys.
B 537, 443 (1999).
2) M. Alford, J. Berges, and K. Rajagopal: Nucl. Phys. B
571, 269 (2000).
3) K. Iida and G. Baym: Phys. Rev. D 66, 014015 (2002).
4) I. Giannakis and H.-C. Ren: Nucl. Phys. B 669, 462(2003).

RIKEN Accel. Prog. Rep. 39 (2006)

Quarkonia correlators and spectral functions on anisotropic lattices
A. Jakovác,∗1 P. Petreczky, K. Petrov,∗2 and A. Velytsky∗3
Temporal meson correlation functions in Euclidean
time can be related to meson spectral functions by analytic continuation. Furthermore using the Maximum
Entropy Method (MEM) one can extract the spectral
functions from meson correlators calculated on a ﬁnite
lattice.1) The method was applied at zero1) as well as
non-zero temperatures.2–5) In particular, in Refs. 3–5
the charmonium spectral functions have been calculated and the calculations have shown that 1S charmonium states (ηc and J/ψ) can exist in the Quark Gluon
Plasma up to temperatures as high as 1.5Tc while the
1P states (χc0 and χc1 ) are dissociated at 1.1Tc . The
statistical and systematic errors in this calculations,however, are not fully under control. In Refs. 4, 5
calculation were done with limited statistics, while inRef. 3 a diﬀerent kind of meson operator was used andcalculations were done only at one lattice spacing.
We have calculated the temporal correlators of local quarkonium operators in the pseudo-scalar, scalarand vector channels which correspond to ηc , χc andJ/ψ states respectively. Calculations were done using
anisotropic quenched lattices and Fermilab formulation.6) Numerical investigation have been done using
the Wilson action at β = 6/g 2 = 5.7, 5.9, 6.1, 6.3
and 6.5 and the anisotropies ξ = as /at = 2 and4. These values of β correspond to lattice spacingsa−1
t = 1.91, 2.91, 8.18, 14.12 GeV. The parameters of
the quark action we ﬁxed non-perturbatively using thevelocity of sound. Typically we calculated the quarkonia correlators on 1000 gauge conﬁgurations.
The spectral functions were reconstructed from thetemporal correlators calculated on the lattice using
MEM. At zero temperature 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 techniques.7)
We ﬁnd that the analysis of the spectral functions with
MEM and constrained curve ﬁtting give consistent results for quarkonia masses mi and decay constants Fi .
Next we have investigated the correlation functionsof charmonia at diﬀerent temperatures in the pseudoscalar and scalar channels. We have found that in thepseudo-scalar channel the correlators do not show signiﬁcant temperature dependence up to temperatures
T ∼ 2Tc , while the correlation function in the scalar
channel were found to be signiﬁcantly diﬀerent fromthe zero temperature correlator already at temperatures T ≥ 1.1Tc . While this is qualitatively consistent
with ﬁnding of Ref. 5 we have also found that there
∗1
∗2
∗3

are small diﬀerences in the temperature dependence ofthe charmonium correlators relative to the results in
Ref. 5. This possibly means that cutoﬀ eﬀects in thetemporal correlators are not completely under control.
The spectral functions reconstructed at ﬁnite temperature using MEM conﬁrmed the expectations based on
the temperature dependence of the correlators: the ηcstate survives till temperatures as high as 1.5Tc , whilethe χc state is dissociated at T ∼ 1.1Tc . This is incomplete agreement with the results of earlier studies.
The temperature dependence of the vector correlators is qualitatively diﬀerent from that in the pseudoscalar channel. This is quite unexpected as both J/ψ
and ηc are 1S state and diﬀer by hyperﬁne splitting.
We expect that their properties should be also very
similar in the medium. It turns out that there is an
extra contribution to the vector spectral function atvery low energies ω ∼ 0 due to transport of heavy
quark in Quark Gluon Plasma. It can be shown that
this contribution causes the diﬀerent temperature dependence of the correlators in vector and pseudo-scalar
channels. A more detailed discussion of this issue canbe found in Ref. 8.
We also studied bottomonia correlators and spectral
functions at ﬁnite temperature. Because of the signiﬁcantly larger quark mass bottomonia states are smaller
in size and thus expected to dissolve at higher temperatures than the corresponding charmonia states. The
pseudo-scalar correlator which corresponds to ηb (1S)state show no temperature dependence till temperatures as high as 2.6Tc . The spectral function also indicate the existence of this state for T > Tc as expected.
The correlator in the scalar channel which corresponds
to χb on the other hand show strong temperature dependence already for T ≥ 1.15Tc and the spectral function is strongly modiﬁed at these temperatures.9)
References
1) M. Asakawa et al.: Prog. Part. Nucl. Phys. 46, 459(2001); T. Yamazaki et al.: Phys. Rev. D 65, 014501(2002).
2) F. Karsch et al.: Phys. Lett. B 530, 147 (2002).
3) T. Umeda et al.: hep-lat/0211003.
4) M. Asakawa and T. Hatsuda: Phys. Rev. Lett. 92,
012001 (2004).
5) S. Datta et al.: Phys. Rev. D 69, 094507 (2004).
6) P. Chen: Phys. Rev. D 64, 034509 (2001).
7) G. P. Lepage et al.: Nucl. Phys. B (Proc. Suppl.) 106,
12 (2002).
8) P. Petreczky et al.: hep-lat/0510021.
9) K. Petrov et al.: hep-lat/0509138.

Budapest Technical University, Hungary
Niels Bohr Institute, Denmark
Department of Physics and Astronomy, University of California, Los Angeles, USA

167

RIKEN Accel. Prog. Rep. 39 (2006)

Recent results from unquenched light sea quark simulations†T. Izubuchi∗
Among the developments in the year of 2005 including the ﬁnalization of the projects of two ﬂavor dynamical domain wall fermion (NF = 2 DWF),1) ﬂavor singlet meson (η  ) spectrum on NF = 2 DWF
conﬁguration,2) the analysis of eﬀective theory in thecase of mixed actions,3) the development of mythology for light-by-light contribution in muon anomalous
magnetic moment, g − 2,4) and the new challenge for
NF = 2 + 1 dynamical simulation,5) an investigationof the electromagnetic (EM) properties6) of hadrons is
described in this article.
As the electric charge of up quarks and that of downquarks diﬀer, isospin symmetry among hadrons is broken at the order of ﬁne structure constant, O(αem ) ∼O(1%), on top of the breaking eﬀect due to the massdiﬀerence between quarks, m− = (mu − md )/2. Thelatter turns out to be very small, O (m2− /ΛQCD )2 ,and the EM eﬀects are dominant in mass diﬀerence
between charged, π ± , and neutral, π 0 , mesons.
In fact, at leading order of chiral perturbation theory
including EM eﬀect, pion masses are given by
(0)

(m)

m2π± = αem ∆+ + 2 (B0 + αem ∆+ ) m+ ,m2π0 =(1)(m)

2 (B0 + αem ∆0 ) m+ ,(2)

m± = (md ±mu )/2 and unknown low energy constants(0,m)
B0 , ∆+,0 . The diﬀerence between the second terms
(m)

(m)

of Eqs. (1) and (2), proportional to ∆+ − ∆0 , expresses the correction to the Dashen’s theorem.
To investigate the EM properties of hadrons nonperturbatively, we carried out QED+QCD simulation
by generating photon ﬁeld, Aem,µ (x), with SU(3) gauge
ﬁeld, Uqcd,µ (x) from the NF = 2 DWF project.1)
Two gauge interactions are incorporated into the Dirac
operator of charge Qq quark, D[Uµ ], substituting
Uµ (x) = Uqcd,µ × exp (iQq Aem,µ ) (x), from which the
propagator Hadrons are then constructed using a wall
source and a point sink. In this article, we focus on
the results of EM mass splitting in the pseudoscalar
sector.
In Fig. 1, the left panel shows the αQED dependenceof a measure of EM splitting deﬁned as the diﬀerence ofsquared masses by the box symbols. Although the sizeof signal is small, the correlation between π 0 and π ±sharing the same SU(3) ensemble helps in the disentanglement of the signal of splitting from statistical noise.
The approximate linearity of points indicates merely asmall contribution from the higher order terms. The
splitting at physical EM charge, αQED = 1/137, asa function of averaged quark mass m+ is plotted in
†
∗

168

Condensed from two articles1,6)Institute for Theoretical Physics, Kanazawa University

Fig. 1. Dependence of EM splitting to αQED (left) and m+(right). Left panel shows squared mass diﬀerences of
π ± compared with charge neutral pion π 0 (circle), andthat to pure QCD pion πQ (square).

the right panel of Fig. 1. The meson interpolationﬁelds employed are the time components of axial vector
current (circle) and pseudoscalar density (box). From(0,m)
these results, we determine B0 and ∆+,0 omitting thehigher order terms, O(αem m± ).
Using the experimental values of pion and kaon
masses as input to Eqs. (1) and (2) and also
their counterparts for kaon masses, multiplying thenon-perturbative quark mass renormalization factor
1/Zm = 0.62,1) we evaluate light quark masses asmMS
u (2 GeV, ref)= 2.84(23) MeV (A4 ), 2.89(8) MeV (P ),mMS
d (2 GeV, ref)= 5.41(24) MeV (A4 ), 5.49(13) MeV (P ),mMS
s (2 GeV, ref)= 106.8(8) MeV (A4 ), 106.5(5) MeV (P ),from each data of interpolation ﬁelds, A4 and P , used.
There are several sources of systematical errors:such as omissions of photon’s vacuum polarization, nondegenerate quark masses, and disconnected diagram,and fnite volume eﬀects. The numbers quoted should
be considered preliminary; however these are encouraging results and we will extend this study to otherhadrons particularly for splitting between proton andneutron,7) g−2 light-by-light project,4) and NF = 2+1
QCD conﬁguration.
References
1) T. Izubuchi: Talk at 23th Int. Symp. on Lattice Field
Theory, Dublin, Ireland, 2005-7.
2) K. Hashimoto and T. Izubuchi: RIKEN Accel. Prog.
Rep. 39, 169 (2006).
3) M. Golterman, T. Izubuchi, and Y. Shamir: Phys. Rev.
D 71, 114508 (2005); hep-lat/0504013.
4) M. Hayakawa, T. Blum, T. Izubuchi, and N. Yamada:
hep-lat/0509016.
5) K. Hashimoto and T. Izubuchi: hep-lat/0510079.
6) N. Yamada, T. Blum, M. Hayakawa, and T. Izubuchi:
hep-lat/0509124.
7) T. Doi et al.: in progress.

RIKEN Accel. Prog. Rep. 39 (2006)

Flavor-singlet pseudoscalar meson in two-flavor domain wall QCD†
K. Hashimoto∗ and T. Izubuchi∗
We report our ongoing calculation of the ﬂavorsinglet pseudoscalar meson (η  ) spectrum in two-ﬂavor
domain wall QCD. η  meson study is one of the mostimportant areas of physics for explaining the quantum
anomaly of U (1)A symmetry and its relation to thenontrivial topology of the QCD vacuum. The breaking of ﬂavor-singlet axial vector current conservation
alters the properties of η  nonperturbatively from thatof ﬂavor nonsinglet mesons, i.e., η  is not an NG boson.
A domain wall fermion1) is one of the lattice chiralfermions that have exact ﬂavor and almost exact chiralsymmetries, even at a ﬁnite lattice spacing (a > 0), andis thus suitable for investigating the nonperturbative
physics of chiral anomaly. We use the Nf = 2 QCD
ensemble of the domain wall fermion and the DBW2
gauge2) actions, in which mπ /mρ is from 0.53 to 0.65,
the lattice size is 163 × 32, the lattice spacing is a−1 ≈1.7 GeV, and the measure of residual chiral symmetry
breaking is mres ∼ 0.1 × mf .3)
The η  propagator is calculated from two parts:η (t)η † (0) = C(t) − 2D(t), in Nf = 2, in whichC(t) is the connected quark loop, the same as the pion
propagator, and D(t) is the correlator of disconnected
loops. Although D(t) is suppressed by the OZI rule, itis propagated picking U (1)A anomaly, m20 ∼ ( F F̃ )2 .
To improve the η  signal, we smear quark operators
in a gauge-invariant manner (Wuppertal smearing):4)

N
3
†
ω2
qL → qS = 1+ 4N(∇+∇)
qL , with the paiii=1
rameters N = 40 and ω = 4.35. Correlators ηI ηJ  arecalculated by contracting local (I, J = L) and smeared(I, J = S) propagators using the Kuramashi method5)on ∼ 2 TFlops QCDOC machines at BNL.
The left panel of Fig. 1 (a) shows a comparison ofsmearing eﬀect for eﬀective η  mass for mf = 0.04. Because we found that ηS ηS  derives the earliest and optimum plateau, we mainly analyze the I, J = S channel.
mη is obtained by the following methods:(A) Fit the ηS ηS  propagator using a single exponential function.
(B) Fit the ratio of C(t) to D(t) using mπ :(1)2D(t)/C(t) = 1 − Be−(mη −mπ )t ,πS (t)πS† (0) = Aπ e−mπ t + e−mπ (Nt −t) .(2)(C) Diagonalize6) the 2 × 2 matrix using:††η  L (t)η  L (0) η  L (t)η  S (0)X(t) =, (3)††η  S (t)η  L (0) η  S (t)η  S (0)†∗Work done under RBC Collaboration
Institute for Theoretical Physics, Kanazawa University(a)(b)
Fig. 1. (a) Comparison of smearing eﬀect of eﬀective mη asfunction of t for mf = 0.04. (b) Ground state eigenvalue
Eq. (4) vs t−t0 for mf = 0.04. Lines show ﬁt ranges andﬁt results by a single exponential function and Eq. (4)respectively.

which is to be diagonalized asdiag.

X −1/2 (t0 )X(t)X −1/2 (t0 )e−m  t−m  (Nt −t)η +eη→  e−mη t0 +e−m  (Nt −t0 )
η

0


0

 . (4)

excited state

Thus, mη is obtained by the ﬁt.
The eﬀect of ﬁnite Nt in Eq. (4) turns out to be negligible and the eigenvalue behaves as a single exponentialfunction as shown in the right panel of Fig. 1 (b) fort0 ≥ 2.
Our preliminary results are shown in Table 1. We
ﬁnd that the methods are consistent with each otherwithin ∼ 20% errors, and method (C) reduces statistical error by up to 50%, which is encouraging.
Table 1. Preliminary results of mπ and mη from diﬀerent
ﬁts. Only statistical errors are quoted.
mf
mπ amη a (A) mη a (B) mη a (C)0.02 0.2955(14) 0.575(98) 0.541(88) 0.540(68)0.03 0.3587(12) 0.710(82) 0.686(81) 0.695(69)0.04 0.4079(12) 0.492(44) 0.475(43) 0.522(22)References
1) D. B. Kaplan: Phys. Lett. B 288, 342 (1992); Y.
Shamir: Nucl. Phys. B 406, 90 (1993); V. Furman et al.:Nucl. Phys. B 439, 54 (1995).
2) T. Takaishi: Phys. Rev. D 54, 1050 (1996); P. de
Forcrand, QCD-TARO Collaboration et al.: Nucl. Phys.
B 577, 263 (2000).
3) Y. Aoki, RBC Collaboration et al.: hep-lat/0411006;
T. Izubuchi, RBC Collaboration: Nucl. Phys. B Proc.
Suppl. 140, 237 (2005); K. Hashimoto and T. Izubuchi,
RBC Collaboration: Nucl. Phys. B Proc. Suppl. 140,
341 (2005).
4) S. Güsken: Nucl. Phys. B Proc. Suppl. 17, 361 (1990).
5) Y. Kuramashi et al.: Phys. Rev. Lett. 72, 3448 (1994).
6) M. Lüscher and U. Wolﬀ: Nucl. Phys. B 339, 222(1990).

169

RIKEN Accel. Prog. Rep. 39 (2006)

Bound state spectrum in finite volume
S. Sasaki and T. Yamazaki
The signature of bound state formation on the lattice is of particular interest. In the inﬁnite volume, thebound state is well deﬁned because there is no continuum state below threshold. However, in a ﬁnite box on
the lattice, all states have discrete energies. Moreover,the lowest level of elastic scattering states appears below threshold if an interaction is attractive between
two particles.1) Therefore, it is hard to clearly distinguish between the “loosely bound state” and the scattering state in this sense.
To study bound states in the ﬁnite volume, we calculate the positronium spectra in the Higgs phase of U (1)gauge dynamics, where photons are massive and thenmassive photons give rise to short-ranged interparticle
force. We try to identify bound state formation by theLüscher’s ﬁnite size method,1) which suggests speciﬁcvolume dependences of the energy gap/shift from thethreshold energy for either bound states or scattering
states.
We perform numerical simulations for positronium
spectra (1 S0 and 3 S1 states) in the Higgs phase of U (1)gauge dynamics (β = 2.0 and h = 0.6) on L3 × 24
lattices with several spatial sizes, L = 8, 10, 12, 16, 20,24.2) The two-point functions of 1 S0 and 3 S1 states areconstructed from the bilinear pseudo-scalar operator
Ψx γ5 Ψx and vector operator Ψx γµ Ψx , respectively. To
evaluate the threshold energy, we also calculate theelectron mass in the Landau gauge.
Figure 1 shows the masses of 1 S0 and 3 S1 positronium states as functions of the electron mass. The left
(right) panel corresponds to results with charge-three(four) electron ﬁelds. The certain energy gap fromthe threshold energy appears in the simulations withcharge-four electron ﬁelds. It is natural to expect thathigher charged electrons provide larger energy gaps because the interparticle force is proportional to (chargeq)2 . For q = 4, the hyperﬁne mass splitting of positronium states is also clearly observed.

The volume dependences of energy gaps ataMelectron  0.5 are shown in Fig. 2. All data thatpoints in the right panel (q = 4) are clearly below thelower bound for the asymptotic solution of the scattering state in the Lüscher’s formula.3) The volume
dependence is drastically changed around L  12–
16. Data for the larger lattice sizes are well ﬁtted by
the form ∆EL = ∆E∞ + La e−bL , which is inspiredby the asymptotic solution of the bound state in theLüscher’s formula.4) The energy gaps for either 1 S0 or
3
S1 states should remain ﬁnite in the inﬁnite volume
limit. Therefore, the bound states of electron-positronare certainly formed in the simulations with chargefour electrons even in the Higgs phase, where interparticle forces are short-ranged.
Although an upward tendency of the L dependence
is observed as spatial size L increases in the left panel(q = 3), all data points are located near the lower
bound for the asymptotic solution of the scattering
state. Also, that the L dependence seems to become
opposite around L  20–24. These observations suggest that the observed states are unlikely the lowest
level of elastic scattering states, rather they are likely
a “loosely bound state.” However, to draw ﬁrm conclusions, more detailed studies and additional data forlarger L are required.

Fig. 2. Mass gaps from threshold energy as functions ofspatial lattice size L in lattice units. Dashed lines represent a lower bound for the asymptotic solution of thescattering state.

References

Fig. 1. Masses of 3 S1 and 1 S0 positronium states as functions of electron mass.

1701) M. Lüscher: Commun. Math. Phys. 104, 177 (1986);
Nucl. Phys. B 354, 531 (1991).
2) S. Sasaki and T. Yamazaki: hep-lat/0510032.
3) K. Yokokawa, S. Sasaki, A. Hayashigaki, and T.
Hatsuda: hep-lat/0509189.
4) S. R. Beane et al.: Phys. Lett. B 585, 106 (2004).

RIKEN Accel. Prog. Rep. 39 (2006)

Study of spin 3/2 pentaquarks in anisotropic lattice QCD†
T. Doi, N. Ishii,∗1 Y. Nemoto,∗2 M. Oka,∗1 and H. Suganuma∗3
The announcement1) of the discovery of the new particle Θ+ (1540), whose minimal conﬁguration is uudds̄,has triggered numerous studies thus far. Experimentally, several groups conﬁrmed the existence of Θ+ ,whereas other groups reported null results.2) Note thateven positive results have determined neither spin nor
parity. Theoretically, one of the central issues is torealize the mechanism for the extremely narrow decay width of Γ <∼ 1 MeV. In this report, we investigate
J = 3/2 possibility. In fact, if Θ+ is a J P = 3/2− state,
the decay to the KN state is of d-wave, leading to ahighly suppressed decay width due to the large centrifugal barrier as well as the wave function factor.3)
On the other hand, J P = 3/2+ possibility attracts another interest because such a state may appear as aspin partner of J P = 1/2+ pentaquark (5 Q).
In this report, we present the analysis of 5 Q in
J P = 3/2± channels using quenched anisotropic lattice QCD. Note that the lattice QCD studies of
5 Q thus far4,5) are restricted to J P = 1/2± channels, except for a very recent one.6) To perform ahigh-precision analysis, we generate 1000 gauge conﬁgurations using the Wilson gauge action at β == 1.1 GeV) on the 123 × 96 lattice with
5.75 (a−1sthe renormalized anisotropy as /at = 4. The O(a)improved Wilson quark action is employed with hopping parameters as κ = 0.1210–0.1240 for u, d-quarks(mπ /mρ = 0.81–0.66) and κs = 0.1240 ﬁxed for squark. To enhance the low-lying spectra, we adopt
gaussian smeared sources. The two-point correlator
is studied using the three types of Rarita-Schwinger
ﬁelds with I = 0: (a) NK∗ -type, abc uTa Cγ5 db uc ·(s̄d γµ dd ) + (u ↔ d), (b) (color-)twisted NK∗ -type,abc uTa Cγ5 db ud·(s̄d γµ dc )+(u  T↔ d) and(c) diquarkT
type, abc def cf g ua Cγ5 db ud Cγ5 γµ de Cγ5 s̄g .
We analyze the eﬀective mass of the correlator, andobserve plateaux except for the result of the diquarktype ﬁeld in J P = 3/2− . In Fig. 1, we show 5 Q masses
that are determined by single-exponential ﬁts. In
J P = 3/2− channel, we ﬁnd that none of the 5 Q states
appear below the NK d-wave threshold, although thisthreshold is raised by 200–250 MeV due to the ﬁnite
extent of the spatial lattice. We perform the linear
chiral extrapolation and obtain m5 Q = 2.17(4) and2.11(4) GeV from NK∗ - and twisted NK∗ -type ﬁelds,
respectively, which are too heavy to be identiﬁed with
Θ+ . In J P = 3/2+ channel, we obtain m5 Q = 2.64(7),2.48(10) and 2.42(6) GeV in the chiral limit from NK∗ -,
†
∗1
∗2
∗3

Condensed from the article in Phys. Rev. D 72, 074503(2005)
Department of Physics, Tokyo Institute of Technology
Department of Physics, Nagoya University
Department of Physics, Kyoto University

Fig. 1. m5 Q against m2π in J P = 3/2± channels. Opencircle, box, triangle symbols denote the results for NK∗ ,twisted NK∗ , and diquark-type fields, respectively, andthe solid lines represent the chiral extrapolations.

twisted NK∗ - and diquark-type ﬁelds, respectively,
which are again too heavy to be identiﬁed with Θ+ .
To understand the nature of the observed plateaux,
we perform the hybrid boundary condition (HBC)
analysis,5) in which we impose the spatially antiperiodic BC (APBC) on u and d-quarks and the periodic
BC (PBC) on s-quark. With HBC, N, K and K∗ aresubject to APBC, whereas Θ+ is still subject to PBC.
Therefore, we expect the energy shift with HBC for NK
and NK∗ states because of the diﬀerence in momentum quantization, whereas the energy shift for Θ+ is
expected to be marginal. In this way, we identify theobserved plateaux as follows. In J P = 3/2− channel,
both plateaux from NK∗ - and twisted NK∗ -type ﬁelds
are regarded as s-wave NK∗ states. In J P = 3/2+
channel, the plateau from an NK∗ -type ﬁeld is most
likely to be an s-wave N∗ K∗ state, whereas the otherplateaux from twisted NK∗ - and diquark-type ﬁelds are
p-wave NK∗ states. In conclusion, we do not observe
any relevant signals of compact 5 Q states.
References
1) LEPS Collaboration, T. Nakano et al.: Phys. Rev. Lett.
91, 012002 (2003).
2) For a review, K. H. Hicks: Prog. Part. Nucl. Phys. 55,
647 (2005), and references therein.
3) A. Hosaka: Phys. Lett. B 571, 55 (2003).
4) F. Csikor et al.: JHEP 0311, 070 (2003); S. Sasaki:
Phys. Rev. Lett. 93, 152001 (2004); T. W. Chiu andT. H. Hsieh: Phys. Rev. D 72, 034505 (2005); N.
Mathur et al.: Phys. Rev. D 70, 074508 (2004); T. T.
Takahashi, T. Umeda, T. Onogi, and T. Kunihiro:
Phys. Rev. D 71, 114509 (2005); B. G. Lasscock etal.: Phys. Rev. D 72, 014502 (2005); C. Alexandrou
and A. Tsapalis: hep-lat/0503013; F. Csikor et al.:hep-lat/0503012; K. Holland and K. J. Juge: heplat/0504007.
5) N. Ishii, T. Doi, H. Iida, M. Oka, F. Okiharu, and H.
Suganuma: Phys. Rev. D 71, 034001 (2005).
6) B. G. Lasscock et al.: Phys. Rev. D 72, 074507 (2005).

171

RIKEN Accel. Prog. Rep. 39 (2006)∆I = 3/2 kaon weak matrix elements with non-zero total momentum
T. Yamazaki for RIKEN-BNL-Columbia Collaboration
The calculation of the K → ππ weak matrix element
is one of the challenging studies in lattice QCD, because it is diﬃcult to calculate directly on a lattice dueto the diﬃculty in the calculation of the two-pion statein ﬁnite volume. To address the problem, many groups
employed an indirect method,1) where the K → ππ
process is reduced to the K → π and K → 0 processes. However, the reduction may cause systematic
errors, because in the decay process the ﬁnal state interaction eﬀect of the two-pion state is expected toplay an important role.
The extraction of the two-pion state with non-zero
relative momentum p = 0 requires complicated calculations and analyses. However, using the non-zero total
momentum (Lab) system, |P | = 0, we can extract thetwo-pion state with p = 0 without complicated calculations and analyzes, because the ground state of thetwo-pion is |π(0)π(P ), which relates to the two-pionstate with p = 0 in the center-of-mass (CM) system.
In the Lab system, however, we cannot naively apply
the formula proposed by Lellouch and Lüscher (LL),2)
which converts the on-shell decay amplitude on ﬁnite
volume to that in the inﬁnite volume, because the formula is derived in the CM system. Before the simulation, we have to extend the LL formula to the Lab system calculation. Very recently, Kim et al.3) and we4)
have proposed the extension of the formula. Here, weapply the extended formula in the calculation of the∆I = 3/2 kaon weak matrix elements.
We employ the quenched lattice QCD using the
DBW2 gauge gluon action with β = 0.87, and the domain wall fermion action with the domain wall heightM = 1.8, and the ﬁfth dimension length Ls = 12.
In the parameters, the lattice spacing corresponds to
a−1 = 1.31(1) GeV. The lattice size is L3 · T = 163 · 32,
where the spatial volume is about 2.4 fm. The number of conﬁguration is 111. Our calculation is carriedout with four pion masses, whose range is mπ = 350–
600 MeV, for the chiral extrapolation of the decay amplitudes. We calculate decay amplitude in the CM
and Lab |P | = 2π/L systems, where the typical relative momenta of the pions are 80 and 260 MeV in eachsystem. Then, we interpolate the decay amplitudes tothe physical momentum 206 MeV.
We calculate the physical quantity of the ﬁnal stateinteraction, the I = 2 ππ scattering phase shift δ, fromthe two-pion energy in each system calculation using
the ﬁnite volume method.5) Figure 1 shows the resultsof δ in each pion mass, and those obtained using thechiral perturbation theory (ChPT).6) We also obtainthe scattering length a0 /mπ = −1.91(12) GeV−2 atthe physical pion mass, which is comparable with thatof ChPT,6) a0 /mπ = −2.265(51) GeV−2 .

172

Fig. 1. Measured scattering phase shift and result of ChPT.

We calculate ReA2 from the measured weak matrix elements. The ReA2 obtained from the CM andLab system calculations are shown in Fig. 2. We
also plot the results previously obtained in several
works.7–10) We estimate ReA2 at the physical point,mπ = 140 MeV and p = 206 MeV, with the ﬁtting
form A00 + A10 m2π + A11 m2π p2 + A01 p2 . The dashedline in the ﬁgure denotes the extrapolation of the result with p = 206 MeV to the physical pion mass. We
obtain ReA2 = 2.55(43) × 10−8 GeV at the physicalpoint, which is 1.70(28)-fold larger than the experimental ReA2 . To understand the diﬀerence from theexperiment ReA2 , we need a more detailed investigation of the systematic errors.

Fig. 2. Measured ReA2 and results of previous works.

References
1) C. W. Bernard et al.: Phys. Rev. D 32, 2343 (1985).
2) L. Lellouch and M. Lüscher: Commun. Math. Phys.
219, 31 (2001).
3) C. Kim et al.: Nucl. Phys. B 727, 218 (2005).
4) N. H. Christ, C. Kim, and T. Yamazaki: Phys. Rev.
D 72, 114506 (2005).
5) K. Rummukainen and S. Gottlieb: Nucl. Phys. B 450,397 (1995).
6) G. Colangelo et al.: Nucl. Phys. B 603, 125 (2001).
7) C. Kim: Nucl. Phys. B (Proc. Suppl.) 140, 381 (2005);
his doctoral thesis.
8) J. Noaki, CP-PACS Collaboration, et al.: Phys. Rev.
D 68, 014501 (2003).
9) T. Blum, the RBC Collaboration, et al.: Phys. Rev. D
68, 114506 (2003).
10) S. Aoki, JLQCD Collaboration, et al.: Phys. Rev. D
58, 054503 (1998).

RIKEN Accel. Prog. Rep. 39 (2006)

Neutron electric dipole moment from lattice QCD
E. Shintani,∗1 S. Aoki,∗1 N. Ishizuka,∗1,∗2 K. Kanaya,∗1 Y. Kikukawa,∗3 Y. Kuramashi,∗1,∗2 M. Okawa,∗4
Y. Taniguchi,∗1,∗2 A. Ukawa,∗1,∗2 and T. Yoshié∗1,∗2
One of the most stringent constraints on the possible
violation of the CP symmetry in the strong interaction
comes from the measurement of the neutron electric
dipole moment (NEDM) dn . The current upper boundis given by |dn | < 6.3 × 10−26 e · cm (90% C.L.).1) On
the other hand, QCD allows a gauge invariant renormalizable CP-odd θ term in the Lagrangian. Crude
model estimations2,3) and the experimental bound on|dn | yield a very stringent bound θ ≤ O(10−10 ).
Current model estimates give not only an order ofmagnitude diﬀerent results on dn but also diﬀer evenin its sign. Clearly, the ﬁrst-principles determinationof dn from lattice QCD is required to determine θ,
if a nonzero value is found for NEDM in future experiments. In this report, we present our result ofa feasibility study for the lattice QCD calculation of
NEDM.4)
We consider the electromagnetic form factor of thenucleon deﬁned as
N (p, s)|JµEM |N (p , s )

F3 (q 2 )= ū(
p, s)qν σµν γ5 + · · · u(p , s ),2mN

a−1 = 1.81(4) GeV determined from ρ meson mass,
on a 163 × 32 lattice. For the quark action, we employ the domain-wall fermion with the ﬁfth dimension
length Ns = 16 and the domain-wall height M = 1.8,
taking the quark mass of mf = 0.03 corresponding tomP S /mV = 0.63. The topological charge Q is calculated by the cooling method with an O(a2 ) improved
deﬁnition. As shown in Ref. 4, 730 conﬁgurations are1
suﬃcient to extract the CP-odd phase parameter fN
from the two-point correlation function, and we obtain1= −0.247(17).
fN
After subtracting the mixing contribution, we obtain
two independent estimates for F3 , which are plotted inFig. 1 as a function of t for τ = 6. The two estimatesagree at a suﬃciently large t, demonstrating the correctness of our formulae. After ﬁtting the results at
12 ≤ t ≤ 15, we obtain
F3 (q 2  0.58 GeV2 )/2mN
−0.024(5) e · θ · fm neutron=.
+0.021(6) e · θ · fm proton

(4)

(1)

where JµEM is the electromagnetic current, q = p − p
is the momentum transfer, |N (p, s) is the on-shellnucleon state with momentum p, energy p0 = m2N + p2
and helicity s. On the right-hand side, we explicitly write the form factor F3 only, which is related to
F3 (q 2 )/2mN = F3 (0)/2mN .
NEDM as |dn | = lim
2
q →0

The electromagnetic form factor can be extracted
from the three-point correlation function
GQp, t)JµEM (q, τ )N̄ (p , 0)Q, (2)N Jµ N (q, t, τ ) = N (calculated in the presence of the topological charge
Q. We can extract F3 in two independent ways, usingQ
tr [GQN J4 N (q, t, τ )Γ4 γ5 ] and tr [GN J4 N (q, t, τ )iΓ4 γ5 γi ],where Γ4 = (1 + γ4 )/2. In addition to the three-point
function, the two-point function is calculated to ex1
astract the mixing coeﬃcient fN
f 1 mNγ5 .
N (p, s)N̄ (p, s)Q = |ZN |2 e−EN t N
2EN

(3)

We calculate two- and three-point functions on 730
quenched gauge conﬁgurations generated with the RGimproved gauge action at β = 2.6, corresponding to
∗1
∗2
∗3
∗4

Graduate School of Pure and Applied Sciences, Universityof Tsukuba
Center for Computational Sciences, University of Tsukuba
Department of Physics, Nagoya University
Department of Physics, Hiroshima University

Fig. 1. F3 for neutron as function of t with current inserted at τ = 6. Circles represent the result with Γ4 γ5projection, while triangles represents that with Γ4 γ5 γj ,averaged over j = 1, 2, 3. Straight lines show the ﬁtting
results for the former.

References
1) P. G. Harris et al.: Phys. Rev. Lett. 82, 904 (1999).
2) R. J. Crewther, P. Di Vecchia, G. Veneziano, and E.
Witten: Phys. Lett. B 88, 123 (1979); erratum, Phys.
Lett. B 91, 487 (1980); P. Di Vecchia: Acta Phys. Austriaca Suppl. 22, 341 (1980).
3) M. Pospelov and A. Ritz: Nucl. Phys. B 558, 243(1999); Nucl. Phys. B 573, 177 (2000); C.-T. Chan,
E. M. Henley, and T. Meissner: hep-ph/9905317; M.
Pospelov and A. Ritz: Phys. Rev. Lett. 27, 2526 (1999);
Phys. Rev. D 63, 073015 (2001); B. Borasoy: Phys. Rev.
D 61, 114017 (2000).
4) E. Shintani, et al.: Phys. Rev. D 72, 014504 (2005).

173

RIKEN Accel. Prog. Rep. 39 (2006)

Status of QCDOC (QCD On a Chip) computer project
P. A. Boyle,∗1 D. Chen,∗2 N. H. Christ,∗3 M. Clark,∗1 S. D. Cohen,∗3 C. Cristian,∗3 Z. Dong,∗3 A. Gara,∗2
B. Joó,∗1 C. Jung,∗3,∗4 C. Kim,∗3 L. Levkova,∗3 X. Liao,∗3 G. Liu,∗3 R. D. Mawhinney,∗3 S. Ohta,∗5,∗6
K. Petrov,∗3,∗4 T. Wettig,∗7 and A. Yamaguchi∗1,∗8
QCDOC (QCD On a Chip) computer project1–7)
was started in 1999 as a joint project of RIKEN,
Columbia University and IBM Research. The UKQCD
Collaboration joined later. The project aimed at providing a computational power in the range of tens of
TFlops optimized for numerical investigations of lattice QCD (Quantum Chromodynamics). QCD is thefundamental theory of the strong interaction of elementary particles. Based on the SU(3) quantum gauge
ﬁeld theory of quarks and gluons, QCD describes the
dynamics of strongly interacting elementary particles
such as proton, neutron, pion, kaon and various atomic
nuclei. Lattice QCD provides both the deﬁnition of
QCD and a method of exactly and accurately extracting the outcome of the theory.
Each QCDOC conﬁguration involves tens of thousands of computational nodes each communicatingwith its twelve nearest neighbors in a six-dimensional
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 embedded-DRAM memory, d)controllers for embedded and external memories, e)a nearest-neighbor serial communication unit (SCU)
with latencies of 350 ns (550 ns) for supervisor (regular)transfers that occur simultaneously in 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. Thirty-two daughterboards are mounted ona motherboard, and eight motherboards are mounted
in a crate with two backplanes. The ﬁnal machine consists of a certain number of such crates.
Last year, we reported the completion of the design and the start of the construction. Before the endof the Japanese ﬁscal year 2004, two 10-TFlops conﬁgurations were completed (see Fig. 1): one for the
RIKEN-BNL Research Center (RBRC) and anotherfor the UKQCD Collaboration. Both conﬁgurations
were immediately provided for lattice QCD research.
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8

174

Department of Physics and Astronomy, University of Edinburgh, Scotland
IBM T. J. Watson Research Center, USA
Department of Physics, Columbia University, USA
Department of Physics, Brookhaven National Laboratory,
USA
Institute of Particle and Nuclear Studies, KEK
Physics Department, Sokendai
Department of Physics, Yale University, USA
Department of Physics and Astronomy, University of Glasgow, Scotland

Fig. 1. Two 10-TFlops configurations of QCDOC computer for RIKEN-BNL Research Center and US DOE,
at Brookhaven National Laboratory.

At the same time, the RIKEN-BNL-Columbia QCD
Collaboration, which had been collaborating in lattice
QCD research using the QCDSP computer, and a partof the UKQCD Collaboration, started a joint collaboration on lattice QCD using three light ﬂavors (verylight and degenerate up and down, and about 100 MeV
strange) of dynamical domain-wall fermions (DWF)
quakrs. This joint collaboration is now carrying out
the calculation of observables regarding nucleon form
factors and structure functions and the ∆I = 1/2 ruleand CP-violating amplitudes of kaon decay. About
2/3 of the RBRC and UKQCD QCDOC computers
are dedicated to this eﬀort. In addition, another 10TFlops conﬁguration of QCDOC was completed thisyear at the request of the US Department of Energy.
This conﬁguration is provided for the use of the US
lattice QCD community at large.
References
1) P. A. Boyle et al.: J. Phys. Conference Series 16, 129(2005).
2) P. A. Boyle et al.: Nucl. Phys. Proc. Suppl. 140, 169(2005).
3) P. A. Boyle et al.: Nucl. Phys. Proc. Suppl. 129, 838(2004); hep-lat/0309096.
4) P. A. Boyle, C. Jung, and T. Wettig, QCDOC Collaboration: hep-lat/0306023.
5) P. A. Boyle et al.: Nucl. Phys. Proc. Suppl. 119, 1041
(2003); hep-lat/0210034.
6) P. A. Boyle, et al.: Nucl. Phys. Proc. Suppl. 106, 177(2002); hep-lat/0110124.
7) D. Chen et al.: Nucl. Phys. Proc. Suppl. 94, 825 (2001);
hep-lat/0011004.

RIKEN Accel. Prog. Rep. 39 (2006)

Measurement of double helicity asymmetry (ALL ) in π 0 productionin proton-proton collisions at RHIC-PHENIX experiment
Y. Fukao,∗ 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 2005 (Run 5), RHIC was operated using longitudinally polarized proton beams with a center ofmass energy of 200 GeV. The average beam polarization (P ) was 47% and the integrated luminosity (L)accumulated at PHENIX1) was 3.8 pb−1 , which are 40
times larger than those in the past years in terms ofﬁgure of merit (P 4 L). In this report, we present the
preliminary results of ALL in the π 0 production of thepT range from 1 GeV/c to 9 GeV/c and at the midrapidity using approximately 50% of the data obtainedin Run 5.
ALL can be calculated using the formulaALL =N++ − RN+−
1,
|PB ||PY | N++ + RN+−

R=

L++
,
L+−

where PB(Y ) is the polarization of the beam rotating (anti)clockwise, N is the yield of π 0 , L is the integrated luminosity and ++ (+−) denotes identical(opposite) helicity beams. We adopted a beam-beamcounter (BBC) to measure R.2) Its error was evaluatedby comparing the BBC counts with those obtained using a zero-degree calorimeter to be δR = 1.0 × 10−4 .
This corresponds to δALL = 2.3 × 10−4 for a beam polarization of 47%, which is suﬃciently small comparedwith the uncertainty from the statistics of π 0 .
Beam polarization was measured using a protoncarbon CNI polarimeter.3) The CNI polarimeter assigned 20% to the error of the beam polarization in
Run 5, which aﬀected the scaling error of double helicity asymmetry by 40%. The PHENIX local polarimeter4) conﬁrmed that the direction of the proton spin in
the PHENIX collision point was more than 98% longitudinal and this eﬀect is fully absorbed in the uncertainty of the absolute polarization.
High pT π 0, s were collected using a high-pT photon trigger5) based on an electromagnetic calorimeterwith an energy threshold of 1.4 GeV. A charged particle veto was applied to purify photons and to reduce
background to the π 0 signal utilizing a pad chamberin front of the calorimeter. Roughly π 0, s of 3 × 107
counts are obtained within a ±25 MeV mass window
in the pT range of 1–9 GeV/c after the cut for particle identiﬁcation. The background fractions in thismass window are 32%, 14% and 7% for 1–2, 2–3 and
3–4 GeV/c π 0 pT bins, respectively, and 5% for a pT of∗

Kyoto University

more than 4 GeV/c.
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
crossing. This can mimic many experimental data.
The ﬂuctuation of ALL generated by a suﬃcient number of shuﬄes should 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 widthof the ALL distribution obtained by bunch shuﬄing, wefound that systematic error is negligible compared withstatistical uncertainty. Note that the systematic error
correlated over all bunches or all ﬁlls cannot be evaluated by this bunch shuﬄing method. The main contributors to these errors are the uncertainty of beampolarization.
Figure 1 shows the Run 5 results of π 0 ALL . Fourtheoretical curves6) based on perturbative quantum
chromodynamics (pQDC) are also shown in the ﬁgure. Our results reject the case that gluon spin aligns
with proton spin maximally (GRSV-max). Note thatthe sensitivity of the data to the theoretical curves isdominated by lower-pT bins at present. More statistics in a higher-pT region would be helpful to further
our knowledge of gluon polarization, where pQCD is
expected to describe the data better. It is also important to study a lower-pT region using other probes,
where soft processes can participate.

Fig. 1. π 0 ALL as a function of pT . The error bars denote
only statistical uncertainty.

References
1) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
2) K. Boyle et al.: RIKEN Accel. Prog. Rep. 39, 197(2006).
3) O. Jinnouchi et al.: RHIC/CAD Accel. Phys. Note, 171(2004).
4) M. Togawa et al.: RIKEN Accel. Prog. Rep. 39, 198(2006).
5) K. Okada et al.: RIKEN Accel. Prog. Rep. 36, 248(2003).
6) B. Jäger et al.: Phys. Rev. D 67, 054005 (2003).

175

RIKEN Accel. Prog. Rep. 39 (2006)

Measurement of direct photons in√
s = 200 GeV p + p collisions

K. Okada, Y. Akiba, Y. Goto, H. Hiejima,∗1 T. Horaguchi,∗2 M. Togawa,∗3 H. Torii, and A. Bazilevsky∗4
Direct photon production in p + p collisions is one of
the simplest processes in QCD. At the RHIC energy,
the dominant process is quark-gluon Compton scattering (q +g → q +γ). The cross section measurement ofsuch a process provides us information on gluon distributions in proton, both unpolarized and polarized.
The analysis is performed with 240 nb−1 of the p + p
data taken in 2003 with the PHENIX central arm detectors.1) We published measurements of direct photon in 5.5 < pT < 7 GeV/c from the 2002 run period.2)
The present data have much higher statistics, and themeasured pT range is extended to 3 < pT < 17 GeV/c.
Photons are detected by the electromagnetic calorimeters (EMCal) and the charged tracking system is used
to reject backgrounds. Photons are selected from clusters in the EMCal by a shape cut, a timing cut and acharged hadron veto cut.
Background photons, mainly from π 0 → γγ decay,
are subtracted by the following π 0 tagging method.
From the invariant mass distribution of any two photons in an event, the number of photons from π 0 decay
is measured statistically in each photon pT bin. This
number of photons from π 0 is then corrected for π 0 detection eﬃciency due to the acceptance, the detector
dead area, and the minimum photon energy threshold. The eﬃciency is estimated by a Monte Carlosimulation. The contributions of other hadronic decays are estimated by multiplying a factor, which is
obtained from the production ratio to π 0 ’s and theirdecay branching ratio to photons. Of all photon clusters, 50(20)% are tagged as photons from π 0 , and85(30)% are estimated as photons from hadrons at
pT = 5(16)GeV/c.
Figure 1 shows the invariant cross section of the direct photon obtained from this analysis together witha next to leading order (NLO) pQCD calculation. In
general, the NLO pQCD calculation describes our datawell. Although the systematic error is large, some excess may exist in the low pT region. One of the possible
explanations is higher-order contributions.
A direct photon is isolated, while a photon fromhadronic decay is accompanied with other jet activities. Thus, when we require little activity around thephoton, photons from hadronic decay are expected tobe suppressed more than direct photons. In Fig. 2, theﬁlled circles show the ratio of direct photons with andwithout an isolation cut. In the same ﬁgure, the ratioof π 0 decay photons is also shown with open circles.
Here, the isolation cut required that less than 10% of
∗1
∗2
∗3
∗4

176

University of Illinois, USA
Kyoto University
Tokyo Institute of Technology
Brookhaven National Laboratory, USA

Fig. 1. Direct photon spectra from subtraction methodwith NLO pQCD calculation.3) Boxes represent the systematic errors. Three lines represent calculations with
3 diﬀerent factorization scales.

Fig. 2. Ratio of result of isolation method to result of subtraction method. Lines represent NLO pQCD calculations.3,4)

the photon energy is observed within a cone of 0.5 [rad]around the photon. As expected, the isolation cut rejects a larger fraction of π 0 decay photons than direct
photons. The direct photons are isolated especially inthe high-pT region. NLO pQCD predictions3,4) for direct photons are also plotted in the ﬁgure. The theory
predictions are consistent with the data.
In summary, we have measured
direct photon pro√duction in p+p collisions at s = 200 GeV. In general,a NLO pQCD calculation describes well both cross section and isolation behaviors. In the lower-pT region, as
our data can not lead to a conclusion with systematic
uncertainties, it is interesting to know whether there
are higher-order contributions.
References
1) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
2) S. S. Adler et al.: Phys. Rev. D 71, 071102 (2005).
3) Private communication with Werner Vogelsang (RBRC).
4) Private communication with Monique Werlen (LAPTH).

RIKEN Accel. Prog. Rep. 39 (2006)

Measurement of transverse single-spin asymmetries with muons in√polarized p+p collisions at s = 200 GeV
H. M. Albataineh,∗1 M. X. Liu,∗2 and X. Wang∗1
The spin structure of the proton has revealed itself
to be extremely complex and is an active area of ongoing research. Large transverse single-spin asymmetries
in inclusive particle production at ﬁxed target energies1,2) were observed in forward pion
√ production by
the E704 collaboration at Fermi Lab ( s = 19.4 GeV).
Such large asymmetries were initially surprising due
to the prediction of pQCD of the leading twist thatthese asymmetries should be small. The interest has
recently grown with the discovery by PHENIX, STARand BRAHMS collaborations that these asymmetries
persist even to RHIC energies.3) Transverse single-spin
asymmetries (SSAs) AN have the potential to be an
important tool in understanding the quark spin distributions in a polarized proton. Precision measurementof SSAs in diﬀerent regions of xF and pT with various
particles and their QCD analysis may serve to quantify
contributions from diﬀerent mechanisms.
We measure the production of single muons using
the PHENIX muon arms which cover the forward rapidity range of (1.2 < |η| < 2.4). The muon candidates are a mix of decay products of light charged
mesons (π ± , K ± ) and heavy quarks (c,b) which canbe identiﬁed and separated by an experimental methods. In general, yields of (µ± ) from (π ± , K ± ) decaystrongly depend on the collision Z vertex: the farther
away the collision vertex from the absorber, the more
likely (π ± , K ± ) will decay. On the other hand, (µ± )from heavy ﬂavor decay is independent of the collisionvertex. Figure 1 shows the Z vertex dependance ofmuon yields with diﬀerent origins.
Here, we report our inclusive analysis with single
muons (µ± ). The left-right single-spin asymmetry AN
can be extracted using
AN =1 σ↑ − σ↓
1 N ↑ − RN ↓=,Pb σ ↑ + σ ↓Pb N ↑ + RN ↓where Pb is the beam polarization, σ ↑ (σ ↓ ) the production cross section when the proton in the bunch ispolarized up (down), N ↑ (N ↓ ) the experimental yieldof muons from such collisions, and R = L↑ /L↓ the relative integrated luminosity. In our analysis, we measure
the asymmetry


↑ ↓
N
N
−
NL↓ NR↑
1
L R


,
(2)
AN ≈
Pb
NL↑ NR↓ + NL↓ NR↑
which is a good experimental approximation of measuring AN deﬁned in Eq. (1), where most of thedetector-related acceptance and eﬃciency uncertainties are canceled out.4) The expected statistical uncertainties for the single-spin asymmetries measured inrun5 estimated from the collected data (L = 0.16 pb−1 ,Pb ∼ 48% average polarization), are shown in Fig. 2 forboth positively (top) and negatively (bottom) charged
muon candidates. Roughly speaking, half of the muoncandidates are muons from light hadron (π ± , K ± )decays and the other half are punch-through light
hadrons (π ± , K ± ); the fraction of muons from heavy
quark decays is very small in this inclusive low-pTmuon sample.

(1)
Fig. 2. Expected accuracy for AN (the top is µ+ and thebottom is µ− ).

References
1) D. L. Adams et al.: Phys. Lett. B 264, 462 (1991).
2) D. L. Adams et al.: Phys. Rev. D 53, 4747 (1996).
3) S. S. Adler et al. The PHENIX Collaboration: Phys.
Rev. Lett. 94, 202001 (2005).
4) H. Spinka: ANL-HEP-TR99-133 (1999).
Fig. 1. Normalized muon event Z vertex.
∗1∗2

New Mexico State University, USA
Los Alamos National Laboratory, USA

177

RIKEN Accel. Prog. Rep. 39 (2006)

Double-spin asymmetry of J/ψ → µ+ µ− in longitudinally polarized√
p + p collisions at s = 200 GeV
I. Younus,∗1 M. Liu,∗2 M. Brooks,∗2 and K. Boyle,∗3 for the PHENIX Collaboration
The heavy quark production in polarized p + p collision at RHIC energy is dominated by gluon-gluon fusion, and thus provides direct access to the polarized
gluon distribution in the proton. The double longitudinal spin asymmetry in heavy quarkonium production
is sensitive to polarized gluon distribution in the nucleon:ALL =σ ++ − σ +−∆g(x1 ) ∆g(x2 ) gg→QQ̄
a
≈
++
+−
σ
+σ
g(x1 ) g(x2 ) LL

where ‘aLL ’ is the partonic level asymmetry.
In this report, we present the results for doublelongitudinal spin asymmetry in J/ψ production inpolarized p + p collisions at RHIC. The J/ψ has
the largest production cross section among all heavy
quarkonia. The PHENIX experiment at RHIC is capable of measuring J/ψ yields through J/ψ → µ+ µ−
channel at forward rapidities (1.2 < |η| < 2.4). Experimentally, ALL is measured as:+++−
1 NJ/ψ − R · NJ/ψ
L++
ALL =
,
R
=
++
+−
PB PY NJ/ψL+−
+ R · NJ/ψwhere N ++ (N +− ) is the number of J/ψ produced in
the same (opposite) helicity state p + p collisions, andPB and PY are the polarization values of the colliding
beams. R is the relative luminosity of diﬀerent helicity
conﬁgurations.1)
During the RHIC run in 2005, PHENIX accumulated 3.8pb−1 of integrated luminosity with an average beam polarization of 47%. For this analysis, weused the local level-1 di-muon triggered data sample(3.2pb−1 ) obtained using the PHENIX muon spectrometer.2)
A single Gaussian ﬁt to µ+ µ− invariant mass spectrum from the entire data set is shown in Fig. 1. An
exponential background under the J/ψ mass peak isassumed in this ﬁt. The total number of J/ψ in theselected sample is 7319 ± 102.0. For ALL calculation,
J/ψ yield was extracted for each RHIC store of thebeam as the relative luminosity varied signiﬁcantly ineach store, but remained constant within a store. Mostof the combinatoric background for µ+ µ− pairs in the
J/ψ mass region was removed using like-sign muonpairs:
NJ/ψ = N (µ+ µ− ) − N (µ+ µ+ , µ− µ− ).
The purity of the J/ψ sample after this subtraction
is above 90%. A global collision vertex range and
∗1
∗2
∗3

178

University of New Mexico, USA
Los Alamos National Laboratory, USA
State University of New York, USA

Fig. 1. Di-muon invariant mass distribution.

muon track quality cuts were applied for event selection. Asymmetry was calculated for each RHIC store
for two pT bins. The average asymmetry values overall stores for each pT bin are:
ALL (< pT >= 0.82) = +0.006 ± 0.088
ALL (< pT >= 2.30) = −0.073 ± 0.091.
The background asymmetry was estimated using theµ+ µ− pairs within 2 < Mmm < 2.5 GeV from theinvariant mass spectrum in Fig. 1, and µ+ µ+ , µ− µ−pairs within 2.6 < Mmm < 3.6 GeV. The averagebackground contribution is estimated to be −0.0041 ±0.018. Currently, the dominant systematic error comesfrom the extraction of J/ψ yield and asymmetry with
diﬀerent mass windows and is expected to improve signiﬁcantly with high statistics data in the future.
Figure 2 shows the ﬁnal ALL results for the two
pT bins along with the theoretical prediction3,4) from
diﬀerent J/ψ production models. The pT averaged
asymmetry is −0.032 ± 0.065(stat). In the future, theexpected 320pb−1 delivered luminosity with improved
beam polarization of 70%, will improve the statisticalﬁgure of merit (P 4 × L) of the double spin asymmetry
by a factor of ∼ 100.

Fig. 2. PHENIX preliminary results for J/ψ asymmetry.

References
1) K. Boyle et al.: RIKEN Accel. Prog. Rep. 39, 197(2006).
2) H. Akikawa et al.: Nucl. Instrum. Methods Phys. Res.
A 499, 537 (2003).
3) A. Tkabladze and O. Teryaev: Phys. Rev. D 56, 7331
(1997).
4) M. Klasen et al.: hep-ph/0306080.

RIKEN Accel. Prog. Rep. 39 (2006)

0

Spin transfer to inclusive Λ hyperons
from longitudinally polarized√
protons at S = 200 GeV
V. L. Rykov, K. Aoki,∗ H. Torii, and PHENIX Collaboration
Correlations between spins of initial and ﬁnal state
hadrons provide the valuable information on the both,polarized parton distributions of initial projectiles aswell as the spin-dependent fragmentation functions of
the produced jets into spin-nonzero hadrons. Sincespin-transfer studies require knowledge of ﬁnal statepolarization, at high energies they are limited almost
exclusively to ﬁnal states with weakly decaying hyperons.1) Spin-transfers from an initial polarization
component Si to a ﬁnal polarization component Sf(Fig. 1) are deﬁned in terms of spin-correlation parameters DSi Sf .
During RHIC runs 3–5 (2003-05) with longitudinally polarized protons, about (1.5–2)×105 of reconstructible Λ → pπ − and Λ → pπ + decays have been
accumulated in the PHENIX Central Arm detectors.2)
Here, we present the analysis on the spin-transfer to Λhyperons, using PHENIX run 3 (2003) data. The analyzed sample corresponds to the integrated luminosityof 206 nb−1 and average beam polarization 34%.
In run 3, the largest statistics of Λ and Λ decays havebeen accumulated in the EMCALa) triggered eventswith the nominal threshold of 1.4 GeV photon energy. This trigger is by a factor of ∼ 4 more sensitiveto Λ- than to Λ-decays, because of antiproton “selftriggering” due to annihilations in the EMCAL. Such“self-triggering” also allows to select a truly inclusive
Λ sample by requiring matching antiproton tracks andtrigger clusters in the EMCAL. For the reasons above,
we concentrated spin-transfer analysis of run 3 data on
Λ-hyperons only.
Candidates to Λ decays have been selected fromidentiﬁed pπ + pairs (Fig. 2) within the invariant mass
window: 1.109 < Mpπ+ < 1.125 GeV/c2 . Charged particle identiﬁcation2) was based on the reconstructed
momenta and time-of-ﬂight measurements with EM-

Fig. 2. Invariant mass spectrum for pπ + pairs (left frame)
and PT distribution of analyzed pairs within Λ mass
window (right frame).

CAL. Pairs within the “side-band” mass window of
1.080–1.095 and 1.160–1.176 GeV/c2 have been used
for evaluating spin-asymmetry correction due to combinatorial background.
Spin-transfer parameters DLL and DLS have beenreconstructed, using parity-violating Λ decay asymmetry for measuring its polarization. We also measured
the double-spin asymmetry ALL for inclusive Λ, whichcharacterizes the cross-section diﬀerence between collisions of protons of same and opposite helicities.
Statistical errors for spin-transfer parameters
achieved with run 3 data are shown in Fig. 3 alongwith the error estimates for run 5. Run 3 analysis isessentially completed, and its results are expected tobe made public soon. Run 5 analysis is currently at
the preparation stage.

Fig. 3. Statistical errors for spin-transfer parametersand ALL in run 3 (solid markers) and error estimates for run 5 (open markers). The errors arefor two bins of PT distribution in Fig. 2: PT <1.5 GeV/c (< PT >= 1.24 GeV/c) and PT > 1.5 GeV/c(< PT >= 1.94 GeV/c). Points are shifted from eachother for the better visibility.
Fig. 1. Kinematics of inclusive production of polarized
fermion. L is spin component along momentum; twoother are perpendicular to momentum: S in production plane and N normal to production plane.
∗a)Kyoto University
PHENIX Electromagnetic Calorimeter.

References
1) A. Bravar et al.: Phys. Rev. Lett. 78, 4003 (1997);
M. R. Adams et al.: Eur. Phys. J. C 17, 263 (2000);
A. Airapetian et al.: Phys. Rev. D 64, 112005 (2001).
2) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).

179

RIKEN Accel. Prog. Rep. 39 (2006)

Measurement of the mid-rapidity helicity asymmetry of η mesons in√
pp collisions at s = 200 GeV
F. Ellinghaus∗ and J. Seele∗ for the PHENIX Collaboration
The contribution of gluons to the nucleon’s spin remains poorly constrained by existing data. Longitudinal double spin asymmetries, ALL , measured for inclusive hadron production in polarized proton-proton
collisions at high energies have been shown1) to be sensitive to the gluon helicity distribution in the nucleon,∆g.
Polarized proton-proton collisions at the Relativistic
Heavy Ion Collider (RHIC) allow for measurements ofp+
ALL .2) This study focuses on ALL in η production (p → η + X), where the η subsequently decays into
two photons. The data was taken at the PHENIX
experiment in 2005. The electromagnetic calorimeteris the primary detector used in this analysis, allowing
for reconstruction of the position and energy of thephotons. Using all possible photon pairs, the invariant
mass is calculated and shown in Fig. 1. Besides theprominent π 0 peak between about 0.1 and 0.2 GeV/c2 ,the η peak (grey region) can also be clearly seen.
A longitudinal spin asymmetry can be written asALL =σ ++ − σ +−
∆σ
,
=
++
+−
σ
+σ
σ

where the cross section σ ++ (σ +− ) describes the reaction where both protons have the same (opposite)
helicity. The spin dependent term can be written as∆fa (x1 ) ⊗ ∆fb (x2 ) ⊗ ∆σ̂ ab→cX (ŝ) ⊗ Dcη
∆σ ∝
abc

where ∆f is a spin dependent parton distribution function (this includes both quarks and gluons) which is
the quantity of interest, ∆σ̂ is a hard scattering crosssection and is calculable in perturbative QCD, and Dcη
is a fragmentation function which can be determinedfrom existing data, e.g., from BELLE. By measuring
this asymmetry and knowing the fragmentation functions and hard cross sections, one can obtain the spin
dependent parton distribution function for the gluon,
i.e. the gluon helicity distribution ∆g.
Experimentally, the double helicity asymmetry is deﬁned asALL =N++ − RN+−
1
L++
, with R ≡,|PB ||PY | N++ + RN+−
L+−

where N++ (N+− ) and L++ (L+− ) are the experimental yield and the luminosity for the case where thebeams have the same (opposite) helicitiy. The achieved
uncertainty on the relative luminosity R is on the orderof 10−4 . The polarizations of the two colliding beams
at RHIC are denoted by PB and PY . The preliminary
average polarization value is 47% with an uncertainty
of 20% per beam.
Calculating the asymmetry in the grey region, consisting of signal (namely the true η’s) and background,and in regions with only background (e.g. the hatchedregions in Fig. 1), the η asymmetry can be extracted
byAηLL =

η+BG− rABG
ALL
LL
,
1−r

with r ≡N BG
N η + N BG.

Based on the data taken in 2005 by the PHENIX collaboration, the expected statistical uncertainty for thelongitudinal double spin asymmetry of the η meson as
a function of pT is shown in Fig. 2.

Fig. 2. Expected accuracy for AηLL as a function of pT .

References
Fig. 1. Two photon invariant mass for pT > 2 GeV/c.
∗

180

University of Colorado, USA

1) G. Bunce et al.: Annu. Rev. Nucl. Part. Sci. 50, 525(2000).
2) PHENIX Collaboration, S. Adler et al.: Phys. Rev.
Lett. 93, 202002 (2004).

RIKEN Accel. Prog. Rep. 39 (2006)±

Charged pion longitudinal double-spin asymmetry AπLL
K. N. Barish,∗ W. S. Emam,∗ and A. Morrealé∗
Charged hadron and pion production in longitudinally polarized proton proton collisions can be used asa probe of the gluon contribution to the proton spin,∆G, and promise to be the ﬁrst measurement sensitive to the sign of ∆G.1) Pions are produced through a
combination of gluon-gluon, quark-gluon, and quarkquark subprocesses, which change in relative strength
as a function of transverse momentum, e.g., as shownin Fig. 1 for neutral pions.
As the quark-gluon contribution becomes sizable,
ALL can become negative if ∆G is negative (see Fig. 2).
π + , π − , and π 0 have diﬀerent quark compositions;thus, ALL is also expected to vary. The measurement

Fig. 1. Relative contributions of gg, qg, and qq for π 0 production.

of charged and neutral pions will be sensitive to both∆G(x) and the sign of ∆G.
In 2005, PHENIX had a signiﬁcant polarized proton
run, recording 3.8 pb−1 with ≈47% polarization. This±
will allow us to measure AπLL up to intermediate pT ,where ALL can start to turn over if ∆G is negative.
In addition to providing an important complimentarymeasurement to the π 0 measurement, we are developing the analysis techniques for future high luminosityand polarization runs.
High-pT pions can be triggered in PHENIX withthe use of the EMCal-RICH trigger (ERT), which canselect events with correlated RHIC and EMCal hits.
Charged pions above 5.5 GeV ﬁre the RICH detector
and deposit energy in the EMCal. To have a reasonable eﬃciency, a low threshold is required for deposted
energy in the EMCal. The expected loss of eﬃciency
was taken into account for the projected sensitivities
shown in Fig. 2. Photon-triggered events, which require only an EMCal energy deposit but with a higher
threshold, and minimum-bias events are also used toenhance the data-set and to study charged hadrons at
a lower transverse momentum. We studied the EMCaland RICH responses for the analysis.
In addition to trigger considerations, pion identiﬁcation and background issues have been investigated.
Backgrounds come from e− and e+ from γ-conversion,and from weak decays, mostly from K± (see Fig. 3).
With appropriate cuts, the background can be minimized.

Fig. 3. Charged pion background sources.

Reference+

Fig. 2. AπLL projections for diﬀerent parameterizations of∆G for the 2005 Run (L = 3.8 pb−1 and P = 47%).

∗

1) B. Jager, A. Schafer, M. Stratmann, and W. Vogelsang:
Phys. Rev. D 67 054005 (2003).

University of California, Riverside, USA

181

RIKEN Accel. Prog. Rep. 39 (2006)kT asymmetry in longitudinally polarized pp collisions at PHENIX
D. E. Fields, J. Rak,∗ I. Younus,∗ and R. Hobbs∗
Researchers in the PHENIX experiment at RHIC
have developed a method for measuring the average
net pair transverse momentum of hard scattered jets at
central rapidity.1) This method utilizes the azimuthal
correlation between a leading high pT π 0 and anothercharged hadron. The widths of the resulting near- andfar-side peaks can then be related to the fragmentationtransverse momentum, jT (the transverse momentumof the fragmented hadron relative to the hard-scatteredparton) and the net pair transverse momentum, kT ina straightforward manner. The net pair transverse momentum can be produced from parton intrinsic transverse momentum inside the proton, from soft gluon
emmission, or from next-to-leading order processes ofthe perturbative QCD. In addition, one can consider
the possibility that spin-correlated transverse momentum (orbital angular momentum) may contribute tokT , as discussed in Ref. 2. Coherent spin-dependent
parton transverse momentum adds to kT an amount
dependent upon the helicity combination of the colliding protons, and upon the impact parameter of thecollision. However, an integration over impact parameter will likely leave a residual eﬀect that is dependent
only on the helicity combination, a signal that could
be examined in the present data from past RHIC runs.
We have examined this kT asymmetry in the 2003
RHIC run. Figure 1 shows the azimuthal angle distribution between triggered π 0 in the transverse momentum range of (3.0 GeV /c < pT t < 7.0 GeV /c) and an
associated charged hadron in the (0.5 GeV /c < pT a <2.5 GeV /c) range for opposite (a) and same (b) helicities for the colliding protons. From these correlation
functions, the widths of the near-side peak (around∆φ = 0) and the far-side peak (around ∆φ = π)
are exctracted. From these, the corresponding values of fragmentation transverse momentum jT , androot-mean-squared (RMS) transverse momentum fraction weighted by a momentum fraction (z) of the fragmented hadron to the scattered parton, (zkT )RM S , aredetermined.
The diﬀerence in the extracted (zkT )RM S for thesame helicity minus the opposite helicity events isshown in Fig. 2. The 2003 RHIC run data set does notshow a signiﬁcant eﬀect. A bunch shuﬄing technique3)
was used to test the errors on the points by randomly
assigning helicity combinations to each RHIC bunch
crossing and then resorting. The distribution of differences in the extracted (zkT )RM S for many sets ofrandomized “shuﬄes” was centered on zero and had
widths (shown as dotted lines in Fig. 2) which wereconsistent with the statistical uncertainties (solid lines
in Fig. 2).
The PHENIX data set from polarized proton running during the 2005 RHIC run has approximately tentimes higher luminosity, and has almost twice the polarization as that of the 2003 RHIC run. Analysis of
this data set is on-going and should be completed soon.

Fig. 2. Diﬀerence in (zkT )RM S for the same helicity minus
opposite helicity events as a function of triggered π 0transverse momentum pT t .
(a)

(b)

References
Fig. 1. Azimuthal correlation functions for opposite (a)and same (b) helicities in the (3.0 GeV /c < pT t <7.0 GeV /c) range of triggered π 0 transverse momentum.

∗

182

University of New Mexico, USA

1) J. Rak: J. Phys. G 30, S1309 (2004).
2) T.-C. Meng et al.: Phys. Rev. D 40, 769 (1989).
3) S. S. Adler et al.: Phys. Rev. Lett. 93, 202002 (2004).

RIKEN Accel. Prog. Rep. 39 (2006)

Double helicity asymmetry in multiparticle production for polarized
proton-proton collisions at PHENIX
K. Nakano∗ , Y. Akiba, and Y. Goto
One of the goals of the PHENIX experiment is to obtain a polarized gluon distribution function in a proton,∆g(x). ∆g(x) is evaluated by measuring the double
helicity asymmetry ALL of reactions in longitudinallypolarized proton-proton collisions, for example, jet
production, π 0 production and direct photon production. A jet is measured as a cluster of multiple particles. The multiparticle measurement gives higher
statistics than single particle measurements such as π 0 .
The ALL is deﬁned asALL =N++ − RN+−
1.
|PB ||PY | N++ + RN+−

(1)

Here, N++ and N+− are the number of measured multiparticle clusters with the same and opposite beam
helicities, respectively; R ≡ L++ /L+− is the relative
luminosity; and PB and PY are the beam polarizations.
√
We used proton-proton collision data at s =200 GeV in 2003 with an average beam polarizationof ∼26%. The integrated luminosity of the analyzed
data is 0.25 pb−1 . The PHENIX Central Arm detectors were used in the analysis. The two arms
are positioned almost back to back, and each arm
covers the pseudorapidity region |η| < 0.35 and the
90-degree azimuthal angle. Photons were measured
with electromagnetic calorimeters, and charged particles were measured with drift chambers and pad chambers. We required that pT > 0.4 GeV/c for photons
and 0.4 < pT < 4 GeV/c for charged tracks. For each
event a high-pT (> 2 GeV/c) photon was required toexist.
Particles that satisﬁed the experimental selections
were clustered by a cone method. Starting from eachparticle in an event as a seed, an interative procedure
was used to deﬁne a conearound a cluster of particles.
The cone radius R (= (∆φ)2 + (∆η)2 ) was set to, was
0.3. The transverse momentum of the cone, pcone
Tdeﬁned as the vector sum of the transverse momentaof the particles in the cone.



 


cone
pT i pT ≡ 
(2)

comparing the simulated events with the real events,
we conﬁrmed that the simulation reproduced the event
shape reasonably well.1) The requirement of a high-pT
photon causes a bias on jet production subprocesses(quark-quark, quark-gluon and gluon-gluon reactions).
This eﬀect was estimated using PYTHIA. In general,the gluon-gluon reaction is suppressed particularly at
low pT .
Figure 1 shows the ALL of the multiparticle pro. Theory predictions
duction as a function of pconeTwith two assumptions on gluon polarization, GRSVstd and ∆g = g input,4) are also shown. The dot
curve in each theory prediction is the original, which= pjetcorresponds to the case of pcone
T
T . Other curvesin each theory prediction have been scaled by the ra/pjettio pconeT
T evaluated with the simulations. The ratio
applied to the thin solid/dash curves was estimated using the PYTHIA default setting, and the ratio applied
to the thick solid/dash curves was estimated using the
PYTHIA MPI setting. In addition, the thin/thicksolid curves have been corrected for the trigger bias
has hardly any
eﬀect. The scale uncertainty in pconeTeﬀect on ALL because of its gradual slope, and it will
be reduced with further studies. The statistical error
will be also reduced by a factor of ∼ 20 in Run 2005
data, and we will be able to distinguish the two models.

Fig. 1. Double helicity asymmetry (ALL ) of multiparticle
production as function of pcone.
Ti∈conein an event was
The cone that gives the largest pconeTused as a cone in the event.
and pjet
The relationship between pcone
T
T was evaluated with PYTHIA and GEANT simulations.1) To
study the inﬂuence of the “underlying event”,2) weused PYTHIA version 6.220 with both the default setting and the “Rick Field MPI tune A” setting.3) By∗

References
1) K. Nakano: Master Thesis, Tokyo Institute of Technology (2004).
2) T. Aﬀolder et al.: Phys. Rev. D 65, 092002 (2002).
3) R. Field, CDF Collaboration: Acta Phys. Pol. B 36,
167 (2005).
4) M. Gluck, E. Reya, M. Stratmann, and W. Vogelsang:
Phys. Rev. D 63, 094005 (2001).

Department of Physics, Tokyo Institute of Technology

183

RIKEN Accel. Prog. Rep. 39 (2006)

Transverse single spin asymmetries at mid-rapidity atin p+p collisions√
s = 200 GeV

M. Chiu,∗1 K. O. Eyser,∗2 and R. Seidl∗1
Large single spin asymmetries have been observedin diﬀerent high energy p+p collisions in the past,1,2)
although they were expected to vanish in perturbative QCD calculations at large transverse momenta(pT ). The spin structure of the nucleon includes aterm called transversity distribution δq, which is different from the longitudinal quark distribution ∆q because relativistic boosts and rotations do not commute.
Transversity therefore probes the relativistic nature of
the nucleon and can be determined from transversely
polarized scattering processes
2

AT T ∝ (δq) ,AN ∝ δq.

(1)

The analyzing power AN poses a direct measure oftransversity in combination with another chiral odd
function. Proposed models include spin dependent
fragmentation functions (Collins eﬀect),3) asymmetries
in the intrinsic transverse momentum distributions ofpartons (Sivers eﬀect),4) and quark gluon ﬁeld interference in higher twist calculations.5) The last one might
have a major impact in the RHIC energy regime, especially at lower pT .
The PHENIX experiment has measured the analyzing power of charged hadrons and neutral pions in the ﬁrst polarized p+p run and results havebeen published.6) Within the polarized run in 2005,
a short period was devoted to transverse polarization
to estimate AT T as a systematic uncertainty in ALL .
The integrated luminosity collected in a signiﬁcantly
shorter period is comparable to the ﬁrst measurement(0.15 pb−1 ) with roughly three times the beam polarization.
Single spin asymmetries in the scattering frame leadto an azimuthal cosine modulation of the diﬀerential
cross section in the laboratory frame. The yields Nl
and Nr in the detector arms (l left and r right)
Nl ∝ L · ∆Ωl · El · (1 + AN · P · cl )Nr ∝ L · ∆Ωl · Er · (1 − AN · P · cr )

(2)
(3)

are dependent on the luminosity L, the detector acceptances ∆Ωl and ∆Ωr and their corresponding eﬃciencies El and Er , and the modulation arising fromthe analyzing power AN and the beam polarization P .
The mean values cl and cr of the cosine modulation in
the respective detector arm is also charge (q) and pT
dependent. The symmetry of the detector with respect
to the cosine modulation causes cl (q, pT ) = cr (q, pT ).
Event quality is based on certain cuts including a
∗1
∗2

184

University of Illinois, USA
University of California, USA

global vertex cut and track quality. Conversion electrons and decay particles with short lifetimes are removed by ring imaging Cherenkov information andtrack matching in the outer detector layers.
In order to remove eﬃciency and relative luminosity
from the asymmetries, an extended square root formula has been calculated  = AN · P :
2 (c + c )2 − 4c c N 2
N+ (cl + cr ) − N+
l
r
l r −
=
. (4)
2cl cr N−
Here, N+ = (N↑2 + N↓2 ) and N− = (N↑2 − N↓2 ), whereN↑2 = N↑,l · N↓,r , and N↓2 , respectively. The arrows
indicate the polarization direction.
Results have been cross checked with simple asymmetries, i. e. asymmetries between detector arms withthe same polarization direction and asymmetries between opposite polarization directions in a single detector arm. The simple asymmetries have therefore
been cleaned of remaining eﬃciencies and luminosities.
Figure 1 shows the results of the analyzing power
for charged hadrons and a comparison of the published results with the new data set. New mean values
have been calculated and are displayed pT -shifted. For
charged hadrons, no evidence of ﬁnite single spin asymmetries can be observed in the considered pT -range.

Fig. 1. Results and statistical errors of the analyzing power
AN for charged hadrons from the year 2005 run compared to the already published data from 2001/02.6)
Additional scaling uncertainties of 20% to 30% have to
be included from the beam polarization.

References
1) D.L. Adams et al.: Phys. Lett. B 264, 462 (1991).
2) J. Adams et al.: Phys. Rev. Lett. 92, 171801 (2004).
3) J. Collins: Nucl. Phys. B 396, 161 (1993).
4) D. Sivers: Phys. Rev. D 43, 261 (1991).
5) Y. Koike: hep-ph/0210396.
6) S. Adler et al.: Phys. Rev. Lett. 95, 202001 (2005).

RIKEN Accel. Prog. Rep. 39 (2006)

Spin-dependent fragmentation function measurements
at Belle experiment
R. Seidl,∗1 D. Gabbert,∗1 M. Grosse-Perdekamp,∗1 K. Hasuko, and A. Ogawa∗2
The Belle experiment1) at the asymmetric e+ e−
collider KEKB2) at Tsukuba, Japan, is mainly dedicated for studying 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 tomeasure spin-dependent and precise spin-independent
fragmentation functions (FFs). Here, the ﬁrst resultson the fragmentation of polarized light quarks into pions obtained on a data set of 29.1 fb−1 are presented.
The Collins eﬀect3) occurs in the fragmentation ofa transversely polarized quark with polarization Sqtransverse to its 3-momentum k into an unpolarizedhadron of transverse momentum Ph⊥ with respect
to the original quark direction. The number density for ﬁnding an unpolarized hadron h produced
from a transversely polarized quark q contains a spindependent term:2)(k̂ × Ph⊥ ) · Sq /zMh ,H1⊥q (z, Ph⊥(1)

metries as the Collins eﬀect, is the radiation of soft
gluons. This gluonic contribution is proportional tothe unpolarized FF and is independent of the chargeof the hadrons. Consequently, taking the ratio of thenormalized distributions for unlike-sign over like-signpairs the gluonic distributions drop out in leading order: N (2φ ) N (2φ0 ) 
0 
.
(2)
R :=


N0 unlikesign
N0 likesign
These double ratios are then ﬁt by the sum of a constant term and a cos(2φ0 ) or cos(φ1 + φ2 ) modulation. The reconstruction of azimuthal asymmetries
was tested by a Monte Carlo simulation. The preliminary results of the cosine ﬁts to the double ratios
are shown in Fig. 1 for charged pion pairs, where the
combined z-bins are obtained by adding the symmetricbins of the 4 × 4 z ∈ [0.2, 0.3, 0.5, 0.7, 1.0] bins. A clear
nonzero asymmetry is visible. Additionally, the datashows a rising behavior with rising fractional energy z.

CM Shwhere z = 2E
Q is the fractional energy the hadron
carries in the center of mass system (CMS). The2) causes a sin(φ) modulaCollins function H1⊥q (z, Ph⊥tion in the azimuthal distribution of the hadron yields
around the original quark momentum axis. φ is theazimuthal angle between the transverse momentum of
the hadron and the plane deﬁned by the quark spin
and its momentum. In e+ e− hadron production, theCollins eﬀect can be observed by correlating the fragmentations of quark and anti-quark in opposing hemispheres. The combination of two hadrons from diﬀerent hemispheres in two-jetlike events, with azimuthal
angles φ1 and φ2 , results in a cos(φ1 + φ2 ) modulationof the observed di-hadron yield. In the CMS, these azimuthal angles are deﬁned between the transverse component of the hadron momenta with regard to the jetaxis n̂ and the plane spanned by the lepton momenta
and n̂. Following Ref. 4 one either computes the azimuthal angle of each pion relative to the jet axis which
results in a cos(φ1 + φ2 ) modulation or one calculates
the azimuthal angle (φ0 ) relative to the axis deﬁned by
the 2nd pion which results in a cos(2φ0 ) modulation.
We measure the normalized yields N (2φ)/N0 , whereN (2φ) denotes the number of hadron pairs in the binsof either 2φ0 or φ1 + φ2 and N0 is the average number of hadron pairs in the whole angle interval. The
main background, producing similar azimuthal asym-∗1∗2

Fig. 1. Double ratio results for cos(2φ0 ) and cos(φ1 + φ2 )methods.

References
1) A. Abashian et al.: Nucl. Instrum. Methods Phys. Res.
A 479, 117 (2002).
2) S. Kurokawa and E. Kikutani: Nucl. Instrum. Methods
Phys. Res. A 499, 1 (2003).
3) J. C. Collins: Nucl. Phys. B 396, 161 (1993).
4) D. Boer, R. Jakob, and P. J. Mulders: Phys. Lett. B
424, 143 (1998).

University of Illinois, USA
Brookhaven National Laboratory, USA

185

RIKEN Accel. Prog. Rep. 39 (2006)

Polarization measurements of 100 GeV proton beams at RHIC
by elastic proton-proton and proton-carbon scattering
I. Nakagawa, I. Alekseev,∗1 A. Bravar,∗2 G. Bunce,∗2 S. Dhawan,∗3 R. Gill,∗2 H. Huang,∗2 W. Haeberli,∗4
G. Igo,∗5 O. Jinnouchi, V. P. Kanavets,∗1 A. Khodinov,∗6 K. Kurita,∗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 two types of polarimeter have been developed
to measure polarizations of proton beams at relativistic heavy-ion collider (RHIC). A pC polarimeter1) provides a relative polarization by measuring asymmetries
in left-right yields (NL , NR ) of recoil carbon events
through elastic proton-carbon reaction. The absolutebeam polarization Pbeam is given by normalizing themeasured asymmetries by the analyzing power for theelastic pC process ApC
N (t)Pbeam =NL − NR,N
L + NR
ApC
(t)
N
1

(1)

where t is 4-momentum transfer. The silicon strip detectors were implemented around 90◦ to select the elastic process to be very peripheral (0.005 < |t| < 0.035(GeV/c)2 ). This is because the t dependent analyzing power is expected to be maximum due to the interference between the electromagnetic and the nuclear strong force amplitudes. This kinematic region is
known as Coulomb Nuclear Interference (CNI) region.
However, because of the poorly known hadronic spinﬂip mechanism at the energy as high as 100 GeV,2)
the ApC
N is not exactly predictable. Thus the relative ApC
N is experimentally determined from the measured t dependence of the asymmetries and its absolutecalibration is obtained from a polarized hydrogen gas
jet polarimeter3) data which was operated in parallelwith the pC polarimeter. Since the target polarization Ptarget is accurately monitored by a Breit-Rabi polarimeter, it can be translated into the absolute beampolarization using a following ratio:
Ptarget=Pbeamtargetbeam(2)where target , beam are left-right asymmetries (NL −NR )/(NL + NR ) observed when either the target or
the beam is polarized, respectively. The ApC
N employed
for Run5 online polarization measurements (see Fig. 1)
was calibrated by the preliminary analysis result of∗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 Stony Brook University, USA∗7 Rikkyo University∗8 Indiana University Cyclotron Facility, USA∗9 Kyoto University∗10 Argonne National Laboratory, USA∗2

186

Fig. 1. Results of online (PHENIX physics store) polarization measurements plotted as a function of the fill number for the blue (top) and the yellow (bottom) beams,
respectively.

the Run4 hydrogen polarimeter data with 8.5% uncertainty. This uncertainty is currently dominated by thestatistics and it will be improved cumulatively as increasing data in Run5 and future runs. During Run5,
it was attempted for the ﬁrst time to perform measurements on both blue and yellow beams simultaneously/sequentially and as a consequence the accumulated statistics amounted about factor of 4 of the Run4
data. On the other hand, the signal was somehow suffered from more backgrounds and S/N ratio was deteriorated by factor of 2. The cause of this is underinvestigation.
The uncertainty of each pC polarization measurement was estimated to be 12 to 19% as a result of Run3and Run4 analyses. The RHIC-spin program requires
to measure the beam polarization within 5% accuracy.
In order to achieve this goal, continuous eﬀorts to improve the polarization measurements have been spentalso for Run5. One of the major modiﬁcations is in the
strip detector of the pC polarimeter. A beam induced
pickup noise was signiﬁcantly suppressed by improving the grounding design of silicon strips. The signal
baseline so stabilized is then expected to reduce theuncertainty introduced in the ADC to energy conversion which was one of the largest error sources of Run3and Run4 data.
References
1) O. Jinnouchi et al.: RIKEN Accel. Prog. Rep. 38, 226(2005).
2) B. Z. Kopeliovich and T. L. Trueman: Phys. Rev. D 64,
034004 (2001).
3) H. Okada et al.: RIKEN Accel. Prog. Rep. 38, 224(2005).

RIKEN Accel. Prog. Rep. 39 (2006)

Mid-rapidity neutral pion production in proton-proton collisions√
at s = 200 GeV
A. Bazilevsky,∗1 A. Deshpande,∗2 Y. Fukao,∗3 and I. Younus∗4
Particle production at large transverse momenta,
pT , in hadronic reactions provides an important testing ground for perturbative Quantum Chromodynamics (pQCD). Successful description of measured particle pT spectra with pQCD is necessary for interpretation of spin asymmetries in terms of polarized gluon
and polarized quark distributions in the nucleon.1) It
also provides a reference needed to quantify nuclear
eﬀects in hadron production in heavy ion collisions.2)
First PHENIX results on inclusive
π 0 production√
from proton-proton collisions at s = 200 GeV in the
1–13 GeV/c π 0 pT range from Year-2002 RHIC run(Run2) has been published.3) The analyzed data corresponded to ∼ 40 nb−1 integrated luminosity. In thispaper we present an update of PHENIX π 0 cross section measurements based on ∼ 2 pb−1 data accumulated by PHENIX during the Year-2005 RHIC run(Run5). It enabled to extend the pT range and to signiﬁcantly decrease the statistical uncertainties of themeasurements.
Analysis method for π 0 cross section measurement
is described in details in ref.3) π 0 → γγ decays weredetected using the electromagnetic calorimeter (EMCal).4) EMCal locates at a radial distance of ∼ 5 mfrom the beam line. Each of the towers in the calorimeter subtends ∆φ × ∆η ∼ 0.01 × 0.01, thus ensuringthat the two photons from a decayed π 0 were clearly
resolved up to a pT of 12 GeV/c. At higher pT themeasured π 0 yields should be corrected for two photon
merging probability, which was carefully studied with
EMCal Monte Carlo simulation and cross checked vsTest Beam data results. The raw π 0 yields were also
corrected for the pT smearing arising from the EMCal
resolutions and the steeply falling spectrum; and forthe losses due to the disabled towers and the incomplete azimuthal coverage.
Low pT part of π 0 spectrum was obtained from“minimum bias” (MB) data sample triggered by beambeam counters (BBC).5) BBCs locate along the beamline at ±1.44 m from the nominal interaction point andsubtended the pseudorapidity range ±(3.0–3.9) withfull azimuthal coverage. The BBC trigger cross sectionin Run5 was traced from Run2 and was found to be
22.9 ± 2.2 mb. Higher pT π 0 measurements were doneusing EMCal based high pT photon trigger3) in coincidence with MB trigger. Its eﬃciency reached a plateauof ∼ 90% at π 0 pT of ∼ 4 GeV/c. Since only a fraction
∗1
∗2
∗3
∗4

Brookhaven National Laboratory, USA
Stony Brook University, USA
Kyoto University
University of New Mexico, USA

of inelastic proton-proton collisions produce particles
which enter BBCs, the MB trigger condition biases therecorded data sample, so only a fraction of the inclusive
π 0 yield was detected. This fraction was determinedwith another photon trigger, which was formed without MB trigger requirements. This fraction was foundto be ∼ 0.78, independent of π 0 pT .
Figure 1 shows the π 0 cross section results in the pTrange from 1 to 20 GeV/c. NLO pQCD calculations6,7)
are consistent with the data over the full range of pT .

Fig. 1. Upper: The invariant diﬀerential cross section
for inclusive π 0 production (points) and the resultsfrom NLO pQCD calculations6) with equal renormalization and factorization scales of pT using the “KniehlKramer-Pötter” sets of fragmentation functions.7) Bottom: The relative diﬀerence between the data and thetheory with scales of pT /2 (lower curve), pT , and 2pT(upper curve). In all ﬁgures, the normalization error of
9.7% is not shown.

References
1) S. S. Adler et al.: Phys. Rev. Lett. 93, 202002 (2004).
2) S. S. Adler et al.: Phys. Rev. Lett. 91, 072301 (2003).
3) S. S. Adler et al.: Phys. Rev. Lett. 91, 241803 (2003).
4) L. Aphecetche et al.: Nucl. Instrum. Methods Phys.
Res. A 499, 521 (2003).
5) M. Allen et al.: Nucl. Instrum. Methods Phys. Res. A
499, 549 (2003).
6) F. Aversa et al.: Nucl. Phys. B 327, 105 (1989); B.
Jäger et al.: Phys. Rev. D 67, 054005 (2003); D. de
Florian: Phys. Rev. D 67, 054004 (2003).
7) B. A. Kniehl et al.: Nucl. Phys. B 597, 337 (2001).

187

RIKEN Accel. Prog. Rep. 39 (2006)

Selection criteria of dimuon decay from J/ψ inproton-proton collisions√
s = 200 GeV

N. Kamihara, for the PHENIX Collatoration
Measuring the J/ψ diﬀerential cross sections in p+p
as a function of the transverse momentum and a function of the rapidity can be a good test that aids in theunderstanding of the J/ψ mechanism.
There are two muon spectrometers (Muon Arm) in
the PHENIX. A Muon Arm consists of a magnet, amuon tracker (MuTr) and a muon identiﬁer (MuID).1)
A MuID is divided into four quadrants in the azimuthal
direction. Each quadrant is used as a trigger counter
for muons.2)
The yield of J/ψ is extracted from dimuon mass
spectra. The mass spectra are obtained from a
triggered dataset. The trigger requires two muonassociated tracks in diﬀerent quadrants of the MuID.
The event selection criteria are categorized by threesteps. The ﬁrst step is conﬁrming that the event satisﬁes the trigger requirement (collision vertex position
and the muon trigger). The second step is selecting
good muon tracks (vertex-matching cuts, the muon reconstruction, and requirement of a hit in the last muon
gap). The third step is counting the J/ψ signal fromthe unlike-sign muon mass spectra.

The vertex position of a muon trajectory issmeared by the multiple scattering in the hadron
absorbers in front of the MuTr. The vertex point
using the BBC and the muon track should be consistent with the expected vertex resolution, which
is mainly governed by the multiple scattering.
The eﬀect of the multiple scattering is estimatedby GEANT simulation. The vertex matching isshown in Fig. 1. Points with error bars are fromreal muon events and the solid line is the resultof the GEANT simulation. The simulation reproduces the real data reasonably well, and the widthof vertex matching is 9 cm. Therefore, we applied±2 sigma cuts (±18 cm) for this selection.
Unlike Sign Pair: J/ψ decays into an oppositecharge muon pair. The unlike-sign pair is required.
The three steps of the selection criteria of the
dimuon from J/ψ are established.

Collision Vertex: The free space along the beam direction around the interaction point is ±40 cm.
Since the collision vertex resolution of the BeamBeam-Counter (BBC)3) is 2 cm, the z position of
event vertex should be within ±38 cm.
Muon Trigger: Due to the trigger hardware limitation, the dimuon trigger requires each muon topass through diﬀerent quadrants of the MuID.
Thus the reconstructed muon tracks should penetrate diﬀerent quadrants. Also, the muon track
should reach the last gap of the MuID.
Vertex Matching: Muons from J/ψ decay point tothe collision vertex. We compare the collision vertices using the BBC and using tracks. The later
one is obtained as follows.
(1) Each muon trajectory at the MuTr is extrapolated to the collision vertex.
(2) Each muon vertex position is determined as
the position closest to the beam orbit on themuon trajectory of (1).
(3) The vertex position is determined as the
midpoint between two muon vertex points.

188

Fig. 1. The vertex matching. The line and the points witherror bars are the result of simulation and the real data,
respectively.

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).

RIKEN Accel. Prog. Rep. 39 (2006)

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,∗4 and W. Xie,
for the PHENIX Collaboration
Heavy quarks (charm and beauty) √are generated
mainly through gluon-gluon fusion 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 heavy quark
production. However, the production mechanism forheavy
quarks remains to be elucidated. At Tevatron√( s = 1.8 TeV and 1.96 TeV p-p̄ collisions), the prediction of pQCD is consistent with the measured D meson cross-section data. However, the theory has large
uncertainty in the fragmentation function and distribution function, and the data are 2 times larger thanthe central value obtained on the basis of the theory.1)
In the PHENIX experiment, heavy quark production
can be measured precisely with single electrons fromthe semi-leptonic decays of charm and beauty mesons.
These measurements can shed new light to our understanding of the production mechanism of heavy quarks.
Electrons are detected by the two central arms of
PHENIX.2) The yield of electrons can be categorized
into nonphotonic and photonic sources. N onphotonic
electrons are mainly from semi-leptonic decays ofcharm and beauty. P hotonic electrons include electrons from the photon conversion and Dalitz decays ofneutral mesons such as π 0 and η. These two components can be decomposed by cocktail subtraction3) andconverter subtraction2) methods. We analyzed about
300 nb−1 of p-p data (in various trigger settings andconfigurations) taken in the 2003 run of RHIC.
Figure 1 shows the invariant pT spectra of electrons
from the semi-leptonic decays of charm and beauty by
the cocktail and converter subtraction methods. These

independent analyses are consistent with each other.
The combination of these results and theoretical calculation are shown in Fig. 2. The data is about 2.5
times larger than that obtained by the Fixed Orderplus Next to Leading Log (FONLL) pQCD calculation.
In future analysis, the spectrum can be extended toa higher-pT region with high statistics. The FONLL
calculation predicts that beauty decay dominates overcharm decay as the source of nonphotonic electrons
above 4 GeV/c in pT . Measurement in the high-pT region is sensitive to beauty production. We can discuss
what type of process contributes to the large cross section by measuring electrons not only from the charmdominant region but also from the beauty-dominantregion.

Fig. 2. Invariant pT spectra of electrons from charm andbeauty combined cocktail and converter subtraction results. The PYTHIA calculation4,5) is tuned to reproduce charm production at SPS and FNAL.6)

Fig. 1. Invariant pT spectra of electrons from charm andbeauty mesons by cocktail and converter subtractions.
∗1
∗2
∗3
∗4

Department of Physics, Kyoto University
Department of Physics, Stony Brook University, State University of New York, USA
Center for Nuclear Study, Graduate School of Science, University of Tokyo
Graduate School of Science, Hiroshima University

References
1) D. Acosta et al.: Phys. Rev. Lett. 91, 241804 (2003).
2) M. Togawa et al.: RIKEN Accel. Prog. Rep. 38, 213(2005).
3) S. S. Adler et al.: hep-ex/0508034.
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).

189

RIKEN Accel. Prog. Rep. 39 (2006)

Measurement of virtual photons at intermediate pT in Au+Au√
collisions at sN N = 200 GeV
Y. Akiba, for the PHENIX collaboration
High energy collisions of heavy nuclei at RHIC produce high-density partonic matter.1) A direct photon
is an important penetrating probe of the dense matter and its time evolution. There are many possible
sources of direct photons in Au+Au collisions at RHIC:
pQCD hard scattering, the collision of high-pT scattered quarks in the dense matter, thermal radiation in
the partonic phase, and thermal radiations from thehadronic phase. There are theoretical predictions that
thermal photons from the partonic phase are the dominant source of direct photons in the intermediate pTrange (1 < pT < 5) GeV/c. The observation of thermal photons in this pT range is therefore direct evidence of the formation of a thermalized partonic matter at RHIC. The initial temperature of the mattercan be directly measured from the emission rate of thethermal photons. The measurement of direct photons
in the intermediate pT range is, however, notoriously
diﬃcult due to a large background from hadronic decay photons: its expected yield is only 10% of that ofbackground photons.
We obtained the ﬁrst promising results of direct photon measurement at the intermediate pT range.2) To
overcome a small signal-to-background ratio, we measured low-mass e+ e− pairs with pT  mee insteadof real photons. These low-mass pairs are almost realvirtual photons, and their emission rates and mass distributions are related to those of real photons.3) An
advantage of this method is that the background contribution from π 0 → γγ decay is strongly suppressedby requiring that the mass of the pair is close to or
larger than π 0 . Since approximately 80% of the background photons are from π 0 , the signal-to-backgroundratio is improved by a factor of 5 or more.
The results are shown in Fig. 1. What we actually
measured in this analysis are the ratios of the yieldof virtual direct photons and virtual inclusive photons∗∗/γincl) in 90 < mee < 300 MeV as a function(γdirectof pT . The ratios are then converted to the invariant
yields of real direct photons using the yields of the realinclusive photons γincl measured by PHENIX with theassumption that the (direct/real) ratio is the same forreal photons.
Are these thermal photons? The rate is higher thana pQCD calculation4) scaled by the number of binary
N + N collisions. In higher pT (pT > 5) GeV/c thepQCD calculation is in good agreement with direct
photon data in p + p,5) but there is no p + p data
in pT < 3 GeV/c. We need reference measurements in

190

Fig. 1. Invariant yield of direct photons in the 0–20% cen√tral Au+Au collisions at sN N = 200 GeV obtained
from the analysis of low mass e+ e− pair.

p+p and d+Au to be able to draw a deﬁnite conclusionon the nature of direct photons in the intermediate pTrange. The same analysis method can be used in p + p
to test the validity of pQCD in this low-pT region, andin d + Au to examine cold nuclear matter eﬀects suchas the Cronin eﬀect.
If the direct photon yield is due to thermal radiation,
the data can enable the ﬁrst direct measurement of theinitial temperature of the matter by comparison between the data and theoretical calculations. Comparison with a model prediction6) yields the values from500 to 600 MeV for Tmax , where Tmax is the maximum
temperature at the center of the ﬁreball. Averaging
over the entire volume leads to smaller values from
300 to 400 MeV. These values are only meaningful ifthese photons are indeed thermal photons; nevertheless, these results are quite intriguing.
References
1) K. Adcox et al.: Nucl. Phys. A 757, 184 (2005).
2) S. Bathe for the PHENIX collaboration: Proc. Quark
Matter 2005, Budapest, Hungary 2005-8, to be published; nucl-ex/0511042.
3) N. M. Kroll and W. Wada: Phys. Rev. 98, 1355 (1955).
4) L. E. Gordon and W. Vogelsang: Phys. Rev. D 48, 3136
(1993).
5) K. Okada et al.: RIKEN Accel. Prog. Rep. 39, 176(2006).
6) D. d’Enterria and D. Peressonko: nucl-th/0503054.

RIKEN Accel. Prog. Rep. 39 (2006)√
Prompt photon production in sN N =200 GeV d+Au collisions
at RHIC-PHENIX
H. Torii, Y. Akiba, A. Bazilevsky, K. Okada for the PHENIX Collaboration

Prompt photon is a good probe for investigating
gluon distribution because the leading subprocess isgluon-quark Compton scattering. In the E7061) experiment, a small excess of photon yield in p+N collisions
compared with p+p collisions was reported. It implies
that the nuclear eﬀect of the N-nucleus aﬀects the initial parton distribution. The PHENIX2) detector constructed at Relativistic Heavy Ion Collider (RHIC) is
designed for studying collisions ranging from p+p to
Au+Au. Here, the measurement of prompt photon in√
d+Au collisions at sN N = 200 GeV is reported.
The PHENIX EMCal3) covers the mid-rapidity region , |η| < 0.35, with granularity ﬁne enough to identify individual photons from π 0 decays. The PHENIX
EMCal-RICH trigger (ERT) was used to select eventswith high-energy photons or electrons. Because thetrigger eﬃciency of ERT plateaued at > 5 GeV for
photons during run 2003, here, only the photons withpT > 5 GeV are selected.

The largest background of the prompt photon production is photons from hadron decay, particularly π 0 .
The ﬁne granularity of EMCal enabled us to identify
photons from π 0 → γ + γ decay from two photon invariant mass spectra. Although the identiﬁcation was
imperfect, 80% of the background could be rejected.
The other background contributions were evaluated ina statistical way on the based of our measurement ofother hadrons and a Monte-Carlo simulation.
Figure 1 shows the obtained result in d+Au collisions and in p+p collisions. A next-to-leading order
pQCD calculation in p+p is shown in the ﬁgure forcomparison; the calculation is scaled with the mean
number of collisions calculated by the Glauber modelin d+Au collisions.
To evaluate the nuclear eﬀect, we calculated a nuclear modiﬁcation factor, (σd+Au )/(σpp × N ), where N
is the mean number of collisions. The obtained factor
shown in Fig. 2 is consistent to the unity within theirsystematic and statistical errors. It indicates that thenuclear eﬀect of Au nuclei is small.
In summary, although statistical and systematic errors are large, we conclude that the measured nuclear
modiﬁcation in Au nuclei is small.

Fig. 2. Nuclear modification factor of prompt photon pro√duction in sN N = 200 GeV d+Au collisions comparedwith π 0 production. An averaged number of nucleon
collisions calculated by the Glauber model is used tonormalize the result in p+p data in comparison with
d+Au data.
Fig. 1. (Top)Cross section of prompt photon production√
in sN N = 200 GeV d+Au collisions and in p+p collisions compared with NLO pQCD calculation. An averaged number of nucleon collisions calculated by the
Glauber model is used to compare the pQCD calculation in d+Au collisions. (Bottom) Ratio of cross section
in d+Au and p+p collisions to NLO pQCD calculation.

References
1) L. Apanasevich et al.: Phys. Rev. D 72, 032003 (2005).
2) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
3) L. Aphecetche et al.: Nucl. Instrum. Methods Phys.
Res. A 499, 521 (2003).

191

RIKEN Accel. Prog. Rep. 39 (2006)√
Measurement of neutral pion in sNN = 200 GeV Au+Au collisions
at RHIC-PHENIX
T. Isobe,∗1 H. Hamagaki,∗1 T. Sakaguchi,∗2 G. David,∗2 S. Mioduszewski,∗3 M. L. Purschke,∗2
D. Winter,∗4 B. Sahlmueller,∗5 in collaboration with PHENIX

The PHENIX experiment1) has been carried out
at the Relativistic Heavy Ion Collider (RHIC) at
Brookhaven National Laboratory (BNL) to ﬁnd evidence of phase transition from normal nuclear matterto Quark Gluon Plasma (QGP). QGP is a new phaseof matter consisting of deconﬁned quarks and gluons.
One of the most intriguing observations at RHIC isthat the yield of π 0 at high transverse momentum (pT )√in central sNN = 200 GeV Au+Au collisions compared with the yield of p+p collision scaled by the
number of underlying nucleon-nucleon collisions is suppressed.2,3) The observed suppression is interpreted asa consequence of the jet-quenching eﬀect, that is, hardscattered partons produced in the initial stage suﬀer alarge energy loss while traversing the hot and dense
matter.
The amount of suppression can be quantiﬁed by anuclear modiﬁcation factor (RAA ). RAA is the ratio between the measured yield and the expected yield fromthe p+p result, and is deﬁned as
RAA (pT ) =d2 NAA /dpT dη
,
TAA (b)d2 σNN /dpT dη

Au+Au collisions.
π 0 s were detected with the
PHENIX electromagnetic calorimeter (EMCal) via thetwo-photon decay mode. To correct the raw π 0 yield,
the geometrical acceptance correction, particle identiﬁcation eﬃciency, and overlapping eﬀect in high multiplicity were estimated using computing clusters at
RIKEN-CCJ.
The large amount of data obtained in RHIC Year4 has made it possible to measure π 0 up to pT ∼20 GeV/c for the central collisions. RAA as a functionof pT was obtained from corrected pT spectra. π 0 dataobtained in PHENIX Year-3 run was used as the p+p
reference. Figure 1 shows the RAA for most central
events (0–10%) together with a theoretical prediction
which employs the GLV model.5) The suppression isvery strong, and it is almost constant at RAA ∼ 0.2 up
to a very high pT . The GLV model describes the strong
suppression well and it indicates the existence of bulk
matter where initial gluon density (dNg /dy) is more√than 1100 in Au+Au collisions at sNN = 200 GeV.

(1)

where the numerator is the invariant π 0 yield in unit
rapidity and the denominator is the expected yield in
p+p collision binary scaled by the number of underlying nucleon-nucleon collisions (TAA (b)) in Au+Au.
TAA (b) is deﬁned as
TAA (b) = Ncoll (b)/σNN ,(2)

where Ncoll (b) is the average number of binary nucleonnucleon collisions determined by distance (b) between
the two nucleons with an inelastic cross section σN N .
If a hard-scattered parton penetrates the bulk matterwithout any nuclear eﬀects, the RAA is unity.
There are several models that provide quantitative
predictions of the amount of suppression. Each model
has various eﬀects: initial state eﬀects, Cronin eﬀect4)
and nuclear shadowing, or strong hadronic ﬁnal stateeﬀects, and energy loss in a dense matter. The systematic study of π 0 production is important to clarify theparton energy loss mechanism in the dense matter.
In RHIC Year-4 run, PHENIX recorded the inte√
grated luminosity of 0.24 nb−1 in sNN = 200 GeV
∗1
∗2
∗3
∗4
∗5

192

Center for Nuclear Study, Graduate School of Science, University of Tokyo
Brookhaven National Laboratory, USA
Texas A&M University, USA
Columbia University, USA
University of Muenster, Germany

Fig. 1. Comparison of π 0 RAA with prediction of RAA using√
GLV model in sNN = 200 GeV Au+Au central (010%) collisions. In addition to the statistical and pTuncorrelated errors, point-to-point varying systematic
errors are shown on the data points as boxes. An overallsystematic error of TAA normalization is shown at 1.

References
1) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
2) S. S Adler et al.: Phys. Rev. Lett. 91, 072301 (2003).
3) S. S Adler et al.: Phys. Rev. Lett. 91, 072303 (2003).
4) J. W. Cronin et al.: Phys. Rev. D 11, 3105 (1975).
5) I. Vitev et al.: Phys. Rev. Lett. 89, 252301 (2002).

RIKEN Accel. Prog. Rep. 39 (2006)

Single electron measurement in PHENIX Run-3 d+Au experimentF. Kajihara,∗1 Y. Akiba, R. Averbeck,∗2 S. Butsyk,∗3 H. Hamagaki,∗1 K. Ozawa,∗1 and M. Togawa,∗4
for the PHENIX Collaboration
Charm production in high-energy nuclear collision
provides information on the initial stage of the reaction. Most of midrapidity charm quarks are produced
via gluon fusion (gg → cc̄).1) Hence, there have been
several attempts to use charm production as a probeof the initial-state gluon density in p + A and A + A
collisions.2,3) Observation of gluon shadowing in heavy
nuclei is of fundamental interest. In addition, charmmeasurement in p + A or d + A collisions provides thebaseline to study pre-equilibrium charm enhancement
and jet quenching in A + A collisions.4) Open-charm
production can be measured through single leptons
from semileptonic decays of charmed hadrons (DD̄).
The semileptonic decays have considerably larger crosssections than the other sources of single leptons suchas the dilepton productions.
In the PHENIX experiment at RHIC, single electrons (e+ or e− ) have been measured at midrapidity√(|y| < 0.35) for d+Au collisions at sN N = 200 GeV.
Inclusive electrons can be categorized into two groups.
The ﬁrst group consists of “photonic” electrons mainly
from the (1) Dalitz decays of mesons (π 0 , η, etc) and(2) external photon conversions. The second groupconsists of “nonphotonic” electrons. The signal electron from semileptonic decays of open charm is thedominant source of the second group. In this report,
we present the status of nonphotonic electron measurement.
To extract nonphotonic electron yield N (pT ) by subtraction of photonic yield P (pT ) from the total, a “converter subtraction” method is applied.5) In the experiment, special runs were performed with a photon converter, a brass sheet (1.68% radiation length) aroundthe MVD detector.6) The photon converter enhances
P (pT ) by a certain factor, Rγ , which is the ratio ofphotonic electron yield with to that without the converter. The measured inclusive electron yield I(pT ) is
given as I(pT ) = P (pT ) + N (pT ) without the converter
and I  (pT ) = Rγ P (pT ) + N (pT ) with the converter.
N (pT ) is obtained by solving these two equations.
In the converter subtraction method, the evaluationof Rγ is most important. A GEANT-based Monte
Carlo simulation was used to evaluate how much thephotonic electron yield is increased by the photon converter and to determine Rγ . The simulation was performed using the PHENIX-CCJ (Computing Center inJapan) and RIKEN Super Combined Cluster (RSCC).
∗1
∗2
∗3
∗4

Center for Nuclear Study, University of Tokyo
Department of Physics and Astronomy, Stony Brook University, State University of New York, USA
Los Alamos National Laboratory, USA
Department of Physics, Kyoto University

The source of photonic electrons in real data is a mixture of mesons (π 0 , η, η  , ω and φ) decaying into real or
virtual photons. However, contributions from π 0 and η
account for almost all of photonic electrons. Therefore,
photonic electrons from only π 0 and η were studied
0in the simulation. Rγ of π 0 (Rγπ ) and Rγ of η (Rγη )were determined separately, and Rγ was determined0
by combining Rγπ and Rγη . For the original π 0 and η
spectra, we used the pT distributions measured in thesame experiment.
√
Figure 1 shows N (pT ) in sN N = 200 GeV d+Au
collisions (close square) which is calculated with the
new result of photonic electron simulation. The error
bars indicate statistic errors only and the squares inthe background indicate systematic errors. The data
are fully corrected for trigger eﬃciency, geometricalacceptance, reconstruction and eID eﬃciency.7) The
spectrum is normalized with the binary collision crosssection by scaling with σpp /(N coll = 8.5) to comparewith the nonphotonic electron spectrum in the Run-2
p+p. Both spectra seem to match well, and no strong
nuclear modiﬁcation is observed in d+Au collisions.
The analysis of nonphotonic electrons in the high-pT
region (≥ 5 GeV/c) is in progress, which is important
for the study of the behavior of b quarks.

√
Fig. 1. Nonphotonic invariant cross section in sN N =200 GeV d+Au collisions (close square), which is normalized with the binary collision cross section.

References
1) S. J. Brodskey et al.: Nucl. Phys. B 369, 519 (1992).
2) Z. Lin and M. Gyulassy: Phys. Rev. Lett. 77, 1222
(1996).
3) K. Geiger: Phys. Rev. D 48, 4129 (1993).
4) B. Müller and X. N. Wang: Phys. Rev. Lett. 68, 2437
(1992).
5) S. S. Adler et al.: Phys. Rev. Lett. 94. 082301 (2005).
6) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
7) F. Kajihara et al.: CNS Annu. Rep. 2003, 51 (2004).

193

RIKEN Accel. Prog. Rep. 39 (2006)

Single electron measurement in PHENIX Run-4 Au+Au experimentF. Kajihara,∗1 Y. Akiba, R. Averbeck,∗2 S. Butsyk,∗3 A. Dion,∗2 H. Hamagaki,∗1 and K. Ozawa,∗1
for the PHENIX Collaboration
A strong suppression of light ﬂavor mesons at a highpT was observed1,2) in high-energy heavy-ion collisions
at RHIC. The leading explanation of this suppressionis that high-pT -scattered partons suﬀer a signiﬁcantenergy loss in an extremely hot and dense QCD matter.3) This eﬀect is considered as strong evidence ofquark-gluon plasma (QGP) formation. The energy
loss for heavy quarks (charm or bottom) was predicted
to be smaller than that of light quarks due to larger
quark masses.4) The measurement for heavy quarks
will extend our knowledge of the mechanism underlying medium-induced parton energy loss.5)
In the RHIC-PHENIX experiment in 2004, we mea√
sured the Au+Au collisions at sN N = 200 GeV.
The measurement of single electrons (e+ or e− ) fromsemileptonic decays of open charm/bottom is useful forinvestigating heavy-quark production. Inclusive electrons can be categorized into two groups. The ﬁrst
group consists of “photonic” electrons mainly from the(1) Dalitz decays of mesons (π 0 , η, etc) and (2) photon conversion. The second is termed “nonphotonic”
electrons. The decays of charm/bottom are the dominant sources of the second group. To extract nonphotonic electron yield by subtracting the photonic
electron background, we used the so-called “cocktail
subtraction” method. This method is used to reconstruct all possible photonic electron components, thatis cocktail, using a hadron-decay simulator on the basis of published pion spectra1,2) and to subtract themfrom the inclusive electron spectrum.6)
Figure 1 shows the nonphotonic electron yield foreach centrality, scaled with the corresponding numberof binary collisions (Ncol ). The brackets and bars indicate the systematical and statistical errors, respectively. The curves are the best ﬁt curves for the Run-3
p+p nonphotonic electron spectrum.6) In central collisions, a strong suppression at a high pT is observed. To
quantify the suppression, the nuclear modiﬁcation factors (RAA ) for each centrality are shown in Fig. 2. The
systematic errors include those of the nuclear thickness
function (TAB ), p + p data, and Au + Au data.
This is a very interesting result: a clear suppressive
eﬀect exists even for nonphotonic electrons from themost central to the midcentral. It indicates that thematter is so dense that even heavy quarks are stopped.
Presently, we are working to improve the error calculations. We use another method (a “converter subtraction” method) of measuring low pT (< 1 GeV/c).
∗1
∗2
∗3

194

Center for Nuclear Study, University of Tokyo
Department of Physics and Astronomy, Stony Brook University, State University of New York, USA
Los Alamos National Laboratory, USA

Fig. 1. pT distribution of nonphotonic electron invariant
yield for each centrality in Run-4 Au + Au comparedwith Run-3 p + p best fit, scaled by Ncol .

Fig. 2. pT distribution of nuclear modification factor (RAA )for each centrality in Run-4 Au + Au.

The measurement will be also extended to the highpT region (≥ 5 GeV/c), where a large b quark decay
contribution is expected.
References
1) K. Adcox et al.: Phys. Rev. Lett. 88, 022301 (2002).
2) S. S. Adler et al.: Phys. Rev. Lett. 91, 072301 (2003).
3) M. Gyulassy and X. N. Wang: Nucl. Phys. B 420, 583(1994).
4) Y. L. Dokshitzer et al.: Phys. Lett. B 519, 199 (2001).
5) N. Armesto et al.: Phys. Rev. D 71, 054027 (2005).
6) M. Togawa et al.: RIKEN Accel. Prog. Rep. 39, 189(2006).

RIKEN Accel. Prog. Rep. 39 (2006)

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 widths of
low-mass vector mesons (ρ, ω and φ) will be modiﬁed.
Some interesting results that suggest 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, Cu+Cu and√
Au+Au collisions at sN N = 200 GeV.
The PHENIX central spectrometer3) can measure
low-mass vector mesons in both leptonic and hadronic
decay channels within the same acceptance at midrapidity. The lepton carries information on mesons deep
inside the hot and dense matter because an electron
does not interact by strong force. The branching ratio of φ → e+ e− to K + K − may be sensitive to themedium eﬀect. In this report, we present the measurement of low-mass vector mesons in the dielectron√
channels in d + Au collisions at sN N = 200 GeV.
The PHENIX experiment at RHIC recorded approximately 1 nb−1 of d+Au collisions in the 2003 run period. Charged particle tracks were reconstructed using
drift chambers and pad chambers. Magnetic ﬁeld isapplied inside the chamber. Then, momentum is calculated by the tracks assuming at charged particles
come from a collision vertex.
Ring Imaging Cerenkov detectors (RICHs) and electromagnetic calorimeters (EMC) were used as online
triggers for an electron (ERT electron trigger). Detailed oﬀ-line identiﬁcation was applied. We required
at least 1 PMT hit of RICH, and energy and timing
measured by EMC are equal to its momentum andlight speed within 3 σ of this resolution, respectively.
Data were taken in two running periods with diﬀerent thresholds of EMC energy, that is, 600 MeV and800 MeV for the single electron. The integrated luminosity of the two periods was approximately the same.
Figure 1 shows the dielectron invariant mass distribution. 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. The backgroundis normalized using a like-sign method. One can clearlyobserve narrow peaks of φ (at 1020 MeV) in the mass
distribution. Its mass and width are consistent withknown values in vacuum and our simulation. Thiswidth is predominated by the experimental resolution∗

Department of Physics, Hiroshima University

Fig. 1. Low-mass dielectron mass distribution in d+Au col√lision at sN N = 200 GeV.

∼ 15 MeV/c2 depending on momentum.
To determine the production cross section of vector
mesons, the observed φ yields have to be corrected for
detector acceptance, electron ID eﬃciency, and trigger
eﬃciency. A simulator of the ERT has been developedand incorporated into the GEANT-based PHENIX
simulation program. Its eﬃciency and trigger mask
were tuned for each 5 period of Run3 d+Au run. We
calculated the trigger eﬃciency of φ for each period. In
this simulation, the variables of EMC energy, matching and timing are tuned using real detector responses
to reduce systematic error of electron identiﬁcation.
We counted signals within 3 sigma of detector resolution calculated by simulation. The count of normalized
mixed events within the same range was subtracted as
background. We calculated combined acceptance andeﬃciency using the simulation program. The corrected
φ spectra are shown in Fig. 2 where vertical bars indicate systematic errors and red boxes indicate systematic errors of only eID, background normalization andsignal counting.
We obtained the corrected transverse energy spectra√of φ mesons at sN N = 200 GeV d+Au collisions in
the PHENIX experiment. Systematic errors need tobe considered more.

Fig. 2. Corrected mT spectra of φ → e+ e− , where verticalbars indicate statistical errors, and red boxes indicate
preliminary systematic error.

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).

195

RIKEN Accel. Prog. Rep. 39 (2006)

Relative luminosity measurements in a high rate environment
D. M. Kawall
The Relativistic Heavy Ion Collider (RHIC) at
Brookhaven National Laboratory has the unique ability to collide beams of high energy polarized protons.1)
This ability presents a signiﬁcant opportunity forphysicists interested in unraveling mysteries associatedwith the spin of the proton.2)
To this end, the PHENIX experiment at RHIC has
made measurements of the double longitudinal spinfrom collisions ofasymmetry in the production of π 0 √like- and unlike-helicity protons at s = 200 GeV.3)
The asymmetry, which is sensitive to the polarized
gluon density in the proton, is determined from:0σ++ − σ+−σ++ + σ+−N++ /L++ − N+− /L+−
1=
|P1 P2 | N++ /L++ + N+− /L+−

p
p
→π X
ALL
=

where +, − refer to the helicities of the colliding
bunches of protons, Pi refers to the polarization ofbeam i, Lab is the luminosity of beams colliding withhelicities a and b, and Nab refers to the helicity-sorted
yield of π 0 . Thus, in addition to measuring the polarizations of the beams and yields of the ﬁnal state ofinterest, we must also measure the relative luminosity
R = L++ /L+− to much better accuracy than the uncertainties on the yields (a reasonable goal would beδR ≈ few ×10−4 ).
Currently R is measured4) with the two beam-beamcounters (BBCs) of PHENIX.5) Each BBC surrounds
the beam pipe 1.44 m upstream or downstream of
the nominal interaction point, and covers a pseudorapidity interval 3.0 < |n| < 3.9. Proton collisions
yielding a coincidence of signals in the two BBCs areinsensitive to the polarization of the colliding beams
at or below the level of 10−3 . Counting such coincidences in a scaler is a good measure of the luminosity,
so we construct R from the ratio of scaler counts forlike-helicity to unlike-helicity bunch pairs.
Systematic corrections to R as constructed above
are required when the collision probability per bunch
crossing gets above 5 or 10% to keep the uncertainty
δR < 10−3 . The correction is required because somecrossings will have 2 or more pp collisions, but thescalers only count 1. Consider an extreme case wherethe ++ bunch crossings have on average 10 pp interactions/crossing, whereas the +− crossings have 8.
Then we would measure 1.0003 with the scaler ratio,
whereas the true R = 1.25. At the design luminosity of
2 × 1032 cm−2 s−1 , we only expect about 1 pp collision
per crossing, but the correction to R from this “saturation” will be too hard to know with the required
accuracy. To overcome this problem we have started

196

to count the number of BBC phototubes hit/crossing.
Multiple pp interactions/crossing lead to a linear increase in phototubes hit, and the “saturation” problem
is lessened.
A second (and worse) problem occurs because thePHENIX central arm acceptance requires that the pp
interaction occurs within 30 cm of the nominal interaction point. Since the bunches delivered by RHIC are
signiﬁcantly wider than this, almost 50% of the eventsoccur outside this range. Currently the vertex position is determined from the diﬀerence in arrival timesof secondary particles at the two BBCs. In a highrate environment with multiple collisions/crossing, thevertex can be reconstructed improperly and we makemistakes deciding which collisions to add to our scaler
counts. Since the vertex proﬁles for ++ and +− arediﬀerent, ambiguities in the vertex determination willlead to a large, intractable uncertainty in R.
To overcome this problem, we used data from thewall current monitor in the RHIC ring.6) This device
measures the charge proﬁle of the colliding bunches,from which one can predict the vertex shape for ++and +− separately (see Fig. 1), free from rate eﬀects.
The observed vertex proﬁle can then be predicted with
suﬃcient accuracy (the RMS width is predicted towithin a few mm for instance) that it seems plausible we can make the required vertex shape dependent
corrections to determine R with high accuracy at highrates.

Fig. 1. Predicted and observed vertex profile.

References
1) I. Alekseev et al.: Nucl. Instrum. Methods Phys. Res.
A 499, 392 (2003).
2) G. Bunce et al.: Annu. Rev. Nucl. Part. Sci. 50, 525(2000).
3) S. S. Adler et al.: Phys. Rev. Lett. 93, 202002 (2004).
4) K. Boyle et al.: RIKEN Accel. Prog. Rep. 39, 197(2006), and references therein.
5) M. Allen et al.: Nucl. Instrum. Methods Phys. Res. A
499, 549 (2003).
6) M. Bei et al.: Nucl. Instrum. Methods Phys. Res. A
499, 372 (2003).

RIKEN Accel. Prog. Rep. 39 (2006)

Relative luminosity studies with polarized protons in RHIC Run5
at PHENIX
K. Boyle,∗1 A. Bazilevsky,∗2 A. Deshpande,∗1 Y. Fukao,∗3 Y. Goto, D. Kawall,∗4 and K. Tanida
One of the main goals of the Relativistic Heavy Ion
Collider (RHIC) is to constrain the gluon contribution
to the proton’s spin using longitudinally polarized protons by measuring the double longitudinal spin asymmetry in diﬀerent production channels. To properly
calculate any asymmetry, we must take into accountthe relative luminosity of bunches with diﬀerent helicities (++ and −− vs. +− and −+). At PHENIX, we
use two beam-beam counters (BBCs) to measure relative luminosity. A second set of detectors, zero-degreecalorimeters (ZDCs), is used in conjunction with theBBCs, to estimate uncertainty in relative luminosity.
This uncertainty is directly related to the ﬁnal uncertainty in our asymmetry measurement.
The BBCs are 1.44 m from the center of the interaction point at |η| = 3.0 to 3.9. A coincidence between
the two BBCs is used to trigger events. The vertex
point is reconstructed, and a ±30 cm cut is imposed.
The ZDCs are 18 m from the interaction point, andcover ±2.8 mrad in the forward and backward directions. We use the ZDCs to trigger events with two
online vertex cuts: ZDCnarrow has a ±30 cm cut, andZDCwide has a ±150 cm cut.
The number of live events triggered by the BBCsand ZDCs are recorded by a set of scaler boards. To
measure relative luminosity, BBC live counts are used.
We simply divide the sum of the counts from like helicity collisions by the sum of counts from unlike helicity
collisions.
The BBCs are high-statistic detectors, and thus we
expect systematic uncertainty to be an important issue. To estimate the accuracy of our result, we compare the values obtained by the BBCs and a second detector system–the ZDCs. We would expect
the ratio of the counts in the two detectors, r(i) =NBBC (i)/NZDCnarrow (i), to be constant independentof bunch crossing i. As there may be some asymmetryin either detector, we actually ﬁt r(i) tor(i) = C[1 + LL S1 (i)S2 (i)].

∗2
∗3
∗4

Fig. 1. A clear correlation is seen between NZDCnarrow /NBBC vs NZDCnarrow /NZDCout . This is due to poor
ZDC resolution (±30 cm) and is corrected for in our
final relative luminosity uncertainty.

(1)Here, Sj (i) is the sign of the helicity of bunch i in beamj. LL = ALL /P1 P2 with Pj the polarization of beamj, and ALL is related to the relative sensitivity of theBBCs and ZDCs to the beam polarization.
A correction is applied to this ratio due to thepoor resolution (±30 cm) of the online ZDC recon∗1

structed vertex position.
A correlation between
NBBC (i)/NZDCnarrow (i) and the ratio of ZDCnarrowcounts to ZDCwide−ZDCnarrow (deﬁned as ZDCout)counts can clearly be seen (Fig. 1). As this eﬀect is dueto the ZDCs, we do not correct our relative luminosity.
With this correction applied, we ﬁt Eq. 1 as described above. We do this on a ﬁll-by-ﬁll basis. (Aﬁll is one store in RHIC, injection to dump). Figure 2
shows LL vs ﬁll number. Fitting this with a constantgives δLL = 2.7 × 10−5 . As the χ2 /N DF is greaterthan unity (371.1/103), we may be underestimatingour uncertainty. Therefore, we enlarge our error byχ2 /N DF , giving us a ﬁnal LL = (1.02 ± 0.52) ×
10−4 . Thus, we conclude that the uncertainty of R in
the 2005 data set is δR = 1.0 × 10−4 . With an averagepolarization of 47%, this contributes an uncertainty in
our measured double spin asymmetry of 2.3 × 10−4 .

Fig. 2. LL vs. fill number after correction for poor ZDC
resolution.

Department of Physics, Stony Brook University, USA
Brookhaven National Laboratory, USA
Department of Physics, Kyoto University
Department of Physics, University of Massachusetts, USA

197

RIKEN Accel. Prog. Rep. 39 (2006)

PHENIX local polarimeter in 2005
M. Togawa,∗1 K. Aoki∗1 , K. Boyle,∗2 A. Deshpande,∗2 Y. Fukao,∗1 Y. Goto, N. Saito,∗1 J. Seele,∗3 andK. Tanida, for the PHENIX Collaboration
One of the main programs of the Relativistic Heavy
Ion Collider (RHIC) experiment is a determination of
the polarized gluon distribution function in the protonbypolarized proton collisions at√ using longitudinally 1)
s = 200 and 500 GeV. In the RHIC ring, the stable direction of the proton polarization is vertical. The
spin rotator magnets, which are located around the experimental area, rotate the spin vector by 90 degrees toenable longitudinal collisions in the PHENIX Interaction Region (IR). The motivation of the PHENIX local
polarimeter is to conﬁrm that the proton is longitudinally polarized in the IR during a run by measuring aremaining transverse neutron asymmetry.2)
The local polarimeter system consists of a Zero-Degree Calorimeter (ZDC) with position-sensitive ShowerMax Detector (SMD).3,4) They cover ±2.8 mrad of theforward and backward directions. The analysis method
is the same as that of previous runs.4) Since improvements in the data acquisition bandwidth (3 ∼ 5 kHz),the trigger for the local polarimeter was allowed to operate at a high rate (∼200 Hz) in 2005. This enableda precise measurement of remaining transverse asymmetries as well as zero backward asymmetries. Finite
backward asymmetries have not been seen and can beused as a cross check on analysis by requiring that theanalysis reproduce this zero asymmetry.
The basis of the hit position measured by the SMD,
left/right and up/down asymmetries were calculated
and plotted against the azimuthal angle. Figure 1
shows the raw transverse spin asymmetries during thecommissioning period with the spin rotators oﬀ (transverse commissioning period) and the normal operation

with the spin rotators on (longitudinal period). Finite
asymmetries were seen during the transverse period
and vanished during the longitudinal period.
The local polarimeter can allow us to measure howmuch the proton beams are longitudinally polarizedusing the following formulas.
 

2 
2
2
PT
AUD
ALR
PT
PL
= 1−
=
,
+
,
P
P
P
Atra.
Atra.
where PL /P and PT /P are the longitudinal and transverse components of the absolute polarization, respectively. ALR and AUD are the left/right and up/down
asymmetry values, normalized by beam polarization,
during the longitudinal period, respectively. Atra. is
the left/right value, normalized by beam polarization,
during the transverse commissioning period.
In 2005, the values of PL /P obtained for the two
beams were 0.995±0.001 and 0.989±0.002. This conﬁrms the beams were fully longitudinallypolarized.
√
Polarized proton collisions at s = 410 GeV werealso performed in 2005. Figure 2 shows√ the raw transverse spin asymmetries during the s = 410 GeV running period. Transverse asymmetries were clearly seenat this high energy.
√ Since similar neutron asymmetries
were found at s = 200 and 410 GeV, similar asymmetries are expected at higher energies. This result
is promising for the transverse√ and longitudinal spincomponent measurements at s = 500 GeV in the future.

√
Fig. 2. Raw transverse asymmetries at s = 410 GeV. The
neutron asymmetry is expected to persist to 500 GeV.
Fig. 1. Raw transverse asymmetries during commissioning√
period at s = 200 GeV with transverse polarization(black circle) and longitudinal polarization (white circle). The polarization of both beams was almost thesame during this period.
∗1
∗2
∗3

198

Department of Physics, Kyoto University
Department of Physics, State University of New York at
Stony Brook, USA
Department of Physics, University of Colorado, USA

References
1) G. Bunce et al.: Annu. Rev. Nucl. Part. Sci. 50, 525(2000).
2) Y. Fukao et al.: RIKEN Accel. Prog. Rep. 36, 232(2003).
3) C. Adler et al.: Nucl. Instrum. Methods Phys. Res. A
470, 488 (2001).
4) A. Deshpande et al.: RIKEN Accel. Prog. Rep. 37, 246(2004).

RIKEN Accel. Prog. Rep. 39 (2006)

PHENIX silicon vertex detector upgrade projectY. Akiba, J. Asai, A. Deshpande,∗1 D. E. Fields,∗2 H. En’yo, K. Fujiwara,∗3 Y. Goto, H. Kano, Z. Li,∗4
H. Ohnishi, Y. Onuki, V. L. Rykov, A. Taketani, M. Tanaka,∗5 J. Tojo, 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 carry out precise 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 future RHIC programs, both for studies of the dense partonic mattercreated in heavy-ion collisions and for the measurements of the nucleon spin-structure function.
The main physics topics addressed by the VTX are
as follows.
• Probing high-density partonic matter◦ Open heavy-quark production◦ Energy loss of charm in dense matter◦ Thermal dileptons from dense matter• Measurements of gluon spin structure of nucleon◦ ∆G/G with heavy-quark production◦ ∆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 inner layers of silicon pixel detectors and two outer layers of silicon strip detectors.
The pixel detector1) has been developed in collaboration with the ALICE group at CERN (RIKEN–ALICE

collaboration). The pixel chips were used and they
worked very well in the NA60 experiment. The silicon
strip detector uses a novel “stripixel” sensor developed
at BNL. The sensor is read out using the SVX4 chipdeveloped at FNAL.
The main points of progress this year are as follows.
• We have a successful review of the project by BNL
in January 2005. The review recommended theconstruction of the detector.
• New collaborators from Ecole Polytechnique,France, joined the project. They take responsibility of the Silicon PIxel Read-Out (SPIRO) board.
• Quality Assurance (QA) of the pixel chips at
CERN and RIKEN2) : Many pieces of pixel sensor
assemblies have been produced and being tested
at RIKEN.
• Development of “pilot” ASIC for the pixel layers3) : The ﬁrst version of the ASIC worked as designed. The second version has been fabricated.
• Development of a thin data bus for the pixel layers4) : A prototype bus has been fabricated.
• Development of a pixel detector assembly system5) : The assembly system will be used to fabricate the ﬁrst prototype ladder.
• An extensive QA of the pre-produciton strip sensor was carried out at BNL6) and at U. New Mexico.7)• The ﬁrst prototype strip detector was fabricated.
The detector was successfully read-out by a prototype Read Oout Card using SVX4.8)• The mechanical design work of the VTX detector
by LANL collaborators and an engineering company (HYTEC) has started.
References

Fig. 1. The PHENIX VTX detector.
∗1
∗2
∗3
∗4
∗5

Stony Brook University, USA
University of New Mexico, USA
Niigata University
Brookhaven National Laboratory, USA
High Energy Accelerator Research Organization (KEK)1) H. Ohnishi et al.: RIKEN Accel. Prog. Rep. 39, 200(2006).
2) K. Fujiwara et al.: RIKEN Accel. Prog. Rep. 39, 207(2006).
3) H. Kano et al.: RIKEN Accel. Prog. Rep. 39, 211(2006).
4) A. Taketani et al.: RIKEN Accel. Prog. Rep. 39, 209(2006).
5) Y. Onuki et al.: RIKEN Accel. Prog. Rep. 39, 205(2006).
6) J. Asai et al.: RIKEN Accel. Prog. Rep. 39, 203 (2006).
7) D. E. Fields et al.: RIKEN Accel. Prog. Rep. 39, 201(2006).
8) J. Tojo et al.: RIKEN Accel. Prog. Rep. 39, 212 (2006).

199

RIKEN Accel. Prog. Rep. 39 (2006)

Development of the silicon pixel detector for PHENIX at CERN
H. Ohnishi, Y. Akiba, J. Asai, H. En’yo, K. Fujiwara, H. Kano, Y. Onuki, and A. Taketani
The relativistic Heavy Ion Collider (RHIC) at
Brookhaven National Laboratory is a machine devoted
to the investigation of two physics topics: highly dense
nuclear matter created by relativistic heavy-ion collisions that may undergo a phase transition from normal nuclear matter to a new state of matter, i.e., quark
gluon plasma (QGP); and the spin structure of the nucleon using polarized proton-proton collisions. Heavyquark measurement (c and b quark) is a key measurement for investigating not only QGP formation but
also nucleon spin structures because heavy quarks aremainly produced via gluon-gluon fusion at the collisionenergy at RHIC. Heavy-quark production is investigated by measuring single electrons using the present
PHENIX detectors.1) However, this measurement islimited by systematic uncertainties caused by large
background contributions such as those from Dalitz
decay of π 0 and η photon conversions; moreover, it is
not possible to separate the charm and beauty contribution models. Therefore, a new vertex tracker, thesilicon vertex tracker (VTX), that enables the precise
measurement of heavy-quark production is proposed.
Various possibilities are investigated carefully inlight of the following requirements.
• Detector should be working under the condition ofa few tracks for proton-proton collisions to several
hundreds of tracks in central heavy-ion collisions.
• All data in the detector should be read out within
40 µs, which is required by the PHENIX data acquisition system.
• Electrons from heavy-quark decay should have an
oﬀset on the order of 100 µm from the primaryvertex position due to the short lifetime of heavy
quarks. To separate such electrons from the major background, those coming mainly from the primary vertex position, the detector should have a
tracking resolution of less than 50 µm.
To satisfy these requirements, the VTX will be builtwith four layers of the silicon detector, consisting of
two inner layers with a silicon pixel detector and twoouter layers with a silicon strip detector.
For the two inner layers, we decided to use the silicon pixel detector technology developed for the ALICE experiment at the Large Hadron Collider (LHC)at CERN. This silicon pixel detector is composed of
two elements: One is a silicon pixel sensor ladder, consisting of four sensor arrays implemented in a linear
arrangement on a single substrate, in which each sensor array consists of 32 × 256 matrixes with an area200

of 425 × 50 µm2 deﬁned by p+ implants on one side ofn-type silicon. The other component is a silicon pixel
readout chip that has 32 × 256 matrixes of readout
electronics containing a preampliﬁer, shapers, a discriminator, a programmable delay and event buﬀers ineach 425 × 50 µm2 cell. This readout chip is processedusing radiation tolerant technology which stands up to
30 Mrad of radiation doses.
The ﬁnal product pixel ladder has four readoutchips interconnected with a pixel sensor via microinterconnections with small balls of solders, which is
known as “bump-bonding”. A PHENIX full ladderconsists of four 4-pixel-chip ladders in a linear arrangement. The ﬁrst layer of the VTX consists of ten fullpixel ladders and the second layer consists of twenty
full pixel ladders surrounding a beam pipe. In total 120
4-chip ladders that consist of 480 pixel readout chips
are required to fabricate full pixel detector layers.
The production of the silicon pixel ladder for
PHENIX is in progress. Figure 1 shows the four bumpbonded ladders produced in our ﬁrst batch of production.
Thirteen bump-bonded ladders have been produced
and delivered to RIKEN thus far. Five more ladders
are now being produced. According to our production
schedule, all necessary bump-bonded ladders (150 ladders including spares) will be delivered by May-June
2006.

Fig. 1. First four delivered bump-bonded ladders.

Reference
1) S. S. Adler et al.: nucl-ex/0510047.

RIKEN Accel. Prog. Rep. 39 (2006)

Evaluation of novel strip-pixel detectors for the silicon vertex
tracker at PHENIX
C. Hægemann,∗ M. Hoeferkamp,∗ A. Zimmerman,∗ J. Turner,∗ M. Malik,∗ and D. E. Fields,∗
for PHENIX VTX Collaboration
As a part of the upgrades for the PHENIX detector
at RHIC, a silicon vertex tracking detector is planned.
This detector will consist of two pixel layers followedby two strip-pixel layers in the barrel region, and four
ministrip layers in the end-cap region. As a part ofthe development phase of the vertex detector, we have
set up three sensor testing facilities at Brookhaven National Laboratory, at the State University of New York,
Stonybrook, and at the University of New Mexico tocharacterize the preproduction sensors, and to develop
our testing and quality assurance plans. Preliminary
results from these tests are presented here.
The PHENIX experiment at RHIC consists of four
spectrometer arms (two in the central rapidity region,and two in the forward rapidity regions), plus several global, event characterization detectors.1) The twomain physics motivations of the experiment are 1) tocharacterize the QCD state created in the collisions ofheavy-ions and 2) to characterize the QCD state in thecollisions of polarized protons.
Lacking presently in the PHENIX configuration isthe ability to distinguish between particles comingfrom the primary vertex, and those coming from decay products of heavy-flavor mesons. To add this capability, PHENIX is currently building a silicon vertex tracking (SVT) detector,2) schematically shown in
Fig. 1. The design consists of a four-layer barrel, built
from two layers of pixel detectors at 2.5 cm and 5 cm
radii, plus two layers of projective “strip-pixel” detectors at 10 cm and 14 cm radii. The coverage of thebarrel section of the detector is −1.2 < η < 1.2 andFig. 1. Schematic layout and dimensions of the SVT,
equipped with two pixel detector, and two strip-pixel
detector barrel layers. Its end-cap extensions will bebuilt from four ministrip detector cones per side.
∗

University of New Mexico, USAφ∼= 2π. End-cap extensions with silicon ministrip detectors assembled into cones will add vertex tracking
capabilities to the forward spectrometers with a coverage of 1.2 < η < 2.2 and φ ∼= 2π.
Performance requirements for the SVT include a)high-precision tracking for displaced vertex measurement (40 µm DCA resolution) for heavy-flavor tagging;b) large-coverage tracking capability with adequate
momentum resolution for jet studies; c) tracking capability in a high charged particle density dN/dη = 700
at η = 0 for heavy-ion physics; d) ability to withstanda high radiation dose of approximately 100 KRad over
10 years; e) read-out in high luminosity p+p running;
and f) a low material budget to avoid multiple scattering and photon conversion for electron measurementby outer detectors. These factors drove the design to“strip-pixel” detectors in the outer two layers of thebarrel detector.
The outer two layers of the silicon barrel requireless precise position resolution, and in order to keep
the channel count as low as possible, two-dimensional
readout silicon strip detectors will be employed. The
sensors currently proposed are based on a novel “strippixel” design developed at BNL.3) The design uses
80 µm × 1 mm “pixels” formed by pairs of interleaved
electrode spirals in a p-on-n material. The pixels areconnected through 3 cm long lines in first and second
metal layers, such that a strip-like projective read-out
in two stereo coordinates is realized (see Fig. 2). Two
strip-pixel arrays, each with 384 + 384 channels on
3 × 3 cm2 , are implemented on a single-sided 600 µm
sensor. The read-out chips are placed on a flexible
printed circuit board mounted on top of the sensor
and are wire-bonded to the end contacts of the readout lines on the periphery of the sensors.
As a part of the development phase of the vertex detector, we have set up three sensor testing facilities at
Brookhaven National Laboratory, at the State University of New York, Stonybrook, and at the University of
New Mexico to characterize the preproduction “strippixel” sensors, and to develop our testing and quality
assurance plans. Initial tests that are performed on thesensor are as follows: a) measure current versus voltage
on the test diodes and on 5% of the strips in order to
identify the breakdown voltage of the p-n junction; b)measure capacitance versus voltage on the test diodes
and on 5% of the strips in order to identify the full
depletion voltage of the p-n-junction; c) measure theleakage current for each strip at full depletion voltage
plus 100 V; and d) measure the capacitance for each

201

(a)
(b)
Fig. 2. (a) Schematic drawing of the p+ cathode structure of the strip-pixel sensor and its two-dimensional
projective readout through lines on two metal layers. (b) Final design of the strip-pixel plaquette.
All readout lines of the second metal layer are routed to the long edges of the sensor.

strip at full depletion voltage plus 100 V. These tests
are necessary to determine the expected leakage current of the detectors and their expected behavior withradiation damage.
These “standard” tests were performed both before
and after the sensor was diced from the wafer (containing three sensors). Figure 3 (a) shows the leakage

current as a function of bias voltage for a single strip ofa 500 µm thick preproduction sensor. The two curves
are the raw (solid line) and temperature-normalized
to 20 C (filled diamonds) curves for the same channel.
The breakdown voltage was not reached at our limitof 500 V and the full depletion voltage was found tobe ≈ 70 V. This was confirmed by the measurement ofcapacitance with bias voltage.
Figure 3 (b) shows the leakage current for a full setof 128 strips at a constant bias voltage of 200 V. The
rise of the leakage current at the beginning and end of
the set is due to the surface currents from neighboring strips not being grounded and is currently being
studied by grounding groups of other strips.
In addition to these tests, we plan to conduct a radiation damage test by exposing the sensor to 200 MeV
protons of known dose and repeating the previous tests
to better understand the leakage current change withradiation dose. We will also conduct a laser charge
sharing study, that will enable us to verify whether the
preproduction design of the sensors meets the design
requirements.
References

Fig. 3. (a) Leakage current as a function of bias voltage for a particular strip of a 500 µm thick preproduction sensor. The two curves are the raw (solid line)
and temperature-normalized (filled diamonds) curves
for the same channel. (b) Leakage current for 128 neighboring strips at constant bias voltage of 200 V. forthe same 500 µm thick preproduction sensor. The two
curves are againthe raw (solid line) and temperaturenormalized (filled diamonds) curves for each channel.
The rise of the leakage current at the beginning andend of the set is explained in the text.

2021) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
2) C. Woody: Proc. 18th Winter Workshop on Nuclear
Dynamics, Nassau, The Bahamas 2002-1 (EP Systema,2002); J. M. Heuser: Nucl. Instrum. Methods Phys. Res.
A 511, 210 (2003); Y. Akiba: AIP Conf. Proc., 698, 785(2003); K. Tanida: Nucl. Instrum. Methods Phys. Res.
A 549, 75 (2005); A. Taketani: Nucl. Instrum. Methods
Phys. Res. A 541, 137 (2005).
3) J. Tojo et al.: IEEE Trans. Nucl. Sci. 51, 2337 (2004);
Z. Li et al.: Nucl. Instrum. Methods Phys. Res. A 541,
21 (2005); Nucl. Instrum. Methods Phys. Res. A 535,
404 (2004).

RIKEN Accel. Prog. Rep. 39 (2006)

Silicon stripixel sensor test and fabrication of support frame forsilicon pixel detector
J. Asai, Y. Akiba, A. L. Deshpande, D. E. Fields, H. En’yo, K. Fujiwara, Y. Goto, H. Kano,
H. Ohnishi, Y. Onuki, A. Taketani, and J. Tojo
We are studying the characteristics of quark gluon
plasma (QGP) and the spin structure of protons using the Relativistic Heavy Ion Collider (RHIC) at
Brookhaven National Laboratory (BNL). PHENIX isa detector for measuring particles in A + A, p(d) + A,
and polarized p + p collisions. A silicon vertex tracker(VTX) will be installed to upgrade PHENIX.1) The
VTX can identify the decay of heavy quarks by theprecise measurement of decay vertex and works as alarge-solid-angle detector. It consists of a barrel detector and a forward detector. In the barrel detector,
the inner two cylindrical layers use a silicon pixel detector and the outer two cylindrical layers use a silicon
stripixel detector. Four layers use a ministrip detector in the forward detector. In this article, we report
the establishment of a quality assurance (QA) station
for the silicon stripixel detector and the developmentof a test prototype support frame for the silicon pixel
detector.
We established the QA station for the silicon stripixel sensor2) at RIKEN BNL Research Center as shownin Fig. 1.3) The main procedures of the QA program
are the visual inspection and characterization measurement of each silicon sensor using a semiautomatic
probe station in a clean room. The probe station
uses a probe card with 128 needles to touch the readout pads of the strip sensor. The bias-voltage dependences of the leakage current (I-V) and capacitance(C-V) of all 1,536 readout pads on a single sensor aremeasured. The preproduction sensors4) of two companies, SINTEF in Norway and Hamamatsu Photonics inJapan were tested. In the visual inspection, there were
bad alignments of through holes in some sensors of
SINTEF. The sensors of Hamamatsu Photonics passed
the visual inspection. The I-V and C-V of a single
strip were measured as shown in Figs. 2 and 3, respectively, while the adjacent 127 strips were grounded tosimulate realistic operation of the sensors. The typical leakage current at full depletion voltage was 1.5 nA
and the capacitance was 1 pF. Breakdown did not occur at 450 V. After the test, the sensor wafers werediced with a laser dicer at BNL Instrumentation Division and were sent to RIKEN Wako to be connected toan SVX4 readout chip5) by wire bonding. The chargesharing property was studied by irradiating infrared(1060 nm wavelength) pulsed laser lights to the detector and reading out signals for the simulation of incident charged particles.6) The QA of 400 mass production sensors will be carried out at BNL, University of
New Mexico7) and Stony Brook University.
We have begun production of the ﬁrst silicon pixel
detector. The pixel detector consists of a silicon sensor, a readout chip, a readout bus,8) a support frame,

Fig. 2. Bias-voltage dependences of leakage current.

Fig. 1. QA station in clean room at RIKEN BNL ResearchCenter.

Fig. 3. Bias-voltage dependences of capacitance.

203and a readout card. One readout unit of a half stave
uses a four-readout-chip ladder with a bump bonded toeach silicon sensor. The four-sensor ladder is mounted
on the support frame.9) To minimize multiple scattering, the support frame should have a low material budget. On the other hand, a high thermal conductivity isnecessary, because the cooling pipe is designed to run
under the support frame. We selected carbon-carbon(C-C) material. For the test of the prototype structure, we made a C-C frame with a thickness of 500 µm,
and a size of 15 × 200 mm2 , and the directions of the
carbon ﬁber intersect the plane shown in Fig. 4 (a).
The readout chip consumes approximately 0.8 W/chip.
The omega board, whose cross section is shown as thecharacter “Ω” (Fig. 4 (b)) and the cooling aluminum
duct for water cooling are placed on the C-C frame.
The omega board is made of isotropic graphite material and formed by cold isostatic pressing (CIP); it has

Fig. 4. C-C support frame (a) and omega structure (b).

204a thickness of 500 µm, a size of 15 × 200 mm2 , and aradius of 5 mm as shown in Fig. 4 (b). A CIP material
is also necessary as a high thermal conduction material. Carbon powder may be emitted from the surfaceof C-C and CIP materials, in which case laminationis required. We selected a parylene coating of 5 µm
thickness. The coating is produced by chemical vapor
deposition using poly-para-xylylene resin.
We will test the ﬁrst production pixel detector witha beam or beta-ray source to measure the eﬃciency atthe beginning of 2006.
References
1) Y. Akiba et al.: RIKEN Accel. Prog. Rep. 39, 199(2006).
2) Z. Li et al.: Nucl. Instrum. Methods Phys. Res. A 518,
300 (2004).
3) J. Asai et al.: RIKEN Accel. Prog. Rep. 38, 235 (2005).
4) J. Tojo et al.: RIKEN Accel. Prog. Rep. 38, 231 (2005).
5) http://www-cdf.lbl.gov/users/mweber/svx4.
6) J. Tojo et al.: RIKEN Accel. Prog. Rep. 39, 212 (2006).
7) D. E. Fields et al.: RIKEN Accel. Prog. Rep. 39, 182(2006).
8) A. Taketani et al.: RIKEN Accel. Prog. Rep. 39, 209(2006).
9) Y. Onuki et al.: RIKEN Accel. Prog. Rep. 39, 205(2006).

RIKEN Accel. Prog. Rep. 39 (2006)

Silicon pixel detector assembly for PHENIX upgrade
Y. Onuki, Y. Akiba, J. Asai, H. En’yo, K. Fujiwara,∗ H. Kano, H. Ohnishi, A. Taketani,and PHENIX VTX Collaboration
The Relativistic Heavy Ion Collider (RHIC) has
been constructed at Brookhaven National Laboratory(BNL)
to provide collisions of polarized proton-proton√√s up to 500 GeV and heavy-ion sN N up to 200 GeV.
The RHIC ring consists of two storage rings and 6 intersection points. The RHIC ring has a circumferenceof 3.8 km. The designed luminosity is 2×1032 cm−2 s−2
in the 500 GeV proton collisions, and the maximum
number of bunches is 120.
The Pioneering High Energy Nuclear Interaction eXperiment (PHENIX) detector has been installed at oneof the 6 intersection points. The PHENIX detector
consists of 2 central arms and 2 muon arms. Central
arms have charged particle and photon detection systems. Muon arms have a muon detection system.
The silicon vertex tracker (VTX) for the PHENIX
is planned to be installed in summer 2009. VTX will
substantially enhance the physics capabilities of the
PHENIX central arm detectors. 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 on gluon polarization in polarized protonproton collisions. The VTX will surround the beampipe, where the collisions occur. VTX consists of two
major parts; the inner two layers are pixel-type sensors
and the outer two layers are strip-type sensors. The
radii of the four layers are 25 mm, 50 mm, 100 mm and
140 mm, respectively.
The inner two pixel layers have 10 and 20 pixel sensor modules (staves) in the φ direction. RIKEN is
assigned to fabricate all staves. A stave is formed of 4
sensor ladders,1,2) each consisting of a silicon pixel sensor matrix of 256 × 128 pixels and 50 × 425 µm2 in size
as a unit. A sensor ladder is a hybrid device consistingof a pixel sensor matrix and 4 readout chips interconnected by bump bonding with micro-solder balls.
A stave can be separated into 4 components: abus3) which is a ﬂexible circuit board made of aluminum and kapton, 4 sensor ladders, a support4) madeof carbon/carbon (C/C) composite, and a cooling
pipe, as shown in Fig. 1. Each component is glued
by two-component epoxy paste adhesive, Araldite
AW106/HV953U, which is known to be a radiationhard adhesive and commonly used in high-energy
physics. Boron-nitride (BN) powder, obtained from
Denka Co., is added to the glue to improve the thermal contductivity between the sensor ladder and the
support. The details of cooling are under investigation.
The pixel sensor adopts a binary readout method.
∗

Science and Technology, Niigata University

Fig. 1. Stave components.

The general intrinsic√ resolution of the binary sensor
is known to be L/ 12, where L is pixel size. It canbe applied to our pixel sensors, and the resolution isabout ∼15 µm. In order to minimize oﬀ-line alignmentby using real tracks, precise alignment of the assemblyis required. We took into account a safety margin andaimed for an assembly precision of 10 µm. A stave fabrication method with high assembly precision and stable quality control should be established before actual
production of the stave. In particular, we considered
the alignment of 4 sensor ladders arranged in a line
and to glue the aligned sensor ladders and support.
It is diﬃcult to align sensor ladders as there is no reliable alignment mark on the sensor ladder except forthe bonding pad for bus connection. Also, we can’t use
the edge of the sensor ladder because the dicing position varies about ∼40 µm from lot to lot. The only way
to conﬁrm that the 4 sensor ladders are well aligned
at 10 µm is to use the pad as an alignment mark because it has suﬃcient position precision relative to the
pixel sensor matrix. We need speciﬁc jigs equippedwith a high-magniﬁcation microscope, precise moving
stage with a gauge, a vacuum chucking mechanism forthe sensor ladder, and a glue dispenser robot. We haveconsulted with Daiya Seiki Co., a precision engineering company in Nagano, to make the jigs for alignment
and assembly of the stave.
Figure 2 shows the alignment jig which aligns theFig. 2. Alignment jig design.
205

sensor ladder along a straight line. The jig has a microscope and precise X-Y-θ stage with vacuum chucking and linear motion (LM) rails with a high-accuracy
running parallelity of < 10 µm/m. The sensor ladderis chucked by the stage and moved to the proper position while viewing the pad through the microscope,
one by one. Figure 3 shows the aligned sensor ladder
positions. The space between sensor ladders, ∆x in
Fig. 4, is observed to be of µm order using the magnetometer equipped with LM rails. The precision of
the space is permitted to be within ∆x < 50 µm at
minimum in Fig. 3, The oﬀset between sensor ladders,∆y, is observed with the microscope by running thestage along the LM rails. Aligned sensor ladders arechecked using the Mitsutoyo 3D vision measuring machine shown in Fig. 4, and are conﬁrmed to be aligned
within the permissible range before gluing.
After alignment, the 4 sensor ladders are glued to the
C/C support. The glue, Araldite AW106/HV953U, isadded with BN ﬁller to improve the coeﬃcient of thermal conductivity (CTC) and is dispensed uniformly
by a programmable automatic dispenser robot madeby Musashi Engneering Co. and shown in Fig. 5. Eachbase laid on the aligned sensor ladders and support

Fig. 3. Position of sensor ladders in a stave.

Fig. 5. Musashi glue dispenser robot.

has a linear bush and linear bush pin. Two bases are
glued together. The glued position of sensor ladders
and support is determined from the diﬀerence between
the bush and pin radii, which is typically on the ∼5 µm
level.
The bus is also glued onto the top of the sensor ladders. The gluing procedure is basically the same asthat for the support. The bus has several alignment
holes. The position accuracy for gluing the bus is determined by the manufacturing precision of the holes.
The precision is 50 µm. The accuracy is suﬃcient toperform wire bonding between sensor ladders and thebus.
These stave components are made of various materials. Therefore we must consider the properties,
thermal conductivity, thermal expansion and Young’s
modulus, shown in Table 1, to maintain a constanttemperature of the assembly room. We are commissioning Hayashi Seimitsu Co. to assemble the stave intheir highly controlled clean room kept at 24 ± 1 degrees.
In summary, the assembly of the PHENIX/VTX detector has been discussed and is now in progress under
the cooperation of researchers and companies. The
ﬁrst trial of manufacturing the stave will be accomplished in December 2005. Furthermore, we are planning to perform the beam test in the spring of 2006.
Table 1. Material properties.
density[g/cm3 ]CTC

CTERadation

Young’s[W/m/K][ppm/K]

length[cm]

modulus[GPa]

2.34
2.7
2.08
8.96
1.95
1.42
1∼4

126
200
23
400

2.6
23
3.0
17

700⊥20

-0.8⊥10

9.36
8.9
20.8
1.43
21.8
28.7
4∼28.6

113
70
55
117
294
∼30
0.4∼10

Si
Al
BN
Cu
C/C
Kapton
Epoxy

0.2
0.2∼3

10∼20
20∼100

References

Fig. 4. Mitsutoyo 3D vision measuring machine.

2061) K. Fujiwara: RIKEN Accel. Prog. Rep. 38, 228 (2005).
2) H. Ohnishi: RIKEN Accel. Prog. Rep. 38, 230 (2005).
3) A. Taketani: RIKEN Accel. Prog. Rep. 38, 233 (2005).
4) J. Asai: RIKEN Accel. Prog. Rep. 38, 235 (2005).

RIKEN Accel. Prog. Rep. 39 (2006)

Evaluation of pixel readout chip and sensor hybrid
for PHENIX upgrade
K. Fujiwara,∗ Y. Akiba, J. Asai, J. M. Heuser, H. En’yo, H. Kano,
T. Kawasaki,∗ H. Ohnishi, Y. Onuki, and A. Taketani
The PHENIX experiment at Relativistic Heavy Ion
Collider (RHIC) of Brookhaven National Laboratory
will be upgraded with a novel four-layer silicon vertex
tracker (VTX) by summer, 2009. The detector can enhance experimental capabilities in both the heavy-ion
and the polarized proton-proton programs at RHIC.
The silicon vertex tracker will identify heavy quark
productions by measuring displaced decay vertices,and will reconstruct jets with the acceptance of almost
full azimuthal coverage over the rapidity of |η| < 1.2.
It has a high spatial resolution of 30–50 µm for the
distance to the closest approach.1) Here, we report thestatus of the evaluations of the readout chips and thesilicon pixel sensor ladder in the PHENIX Silicon Pixel
Detector.
The inner two layers are built from 30 staves withpixel sensors placed cylindrically covering approximately 22 cm along the beam direction. The ﬁrst layer
has a 2.5 cm radius consisting of 10 staves and the second layer has a 5 cm radius consisting of 20 staves.
One stave is divided into two half-staves and a halfstave has two sensor ladders. The sensor ladder shownin Fig. 1 consists of a single sensor and four readoutchips, which are bump-bonded to each other using microscopic solder balls of 15 µm diameter. The size ofthe sensor ladder is 15.6 mm × 57 mm and the total
thickness is ∼ 350 µm. For the two layers, 120 sensor
ladders will be installed.
Because the sensor ladders will be used under a highlevel-radiation environment in the experiment, the radiation hard devices developed by the CERN Micro
Electronics Group for the ALICE experiment were chosen. (The expected total dose is between 100 krad and1 Mrad in 10 years.) The sensor chip is based on the
P+ /N/N+ silicon with the thickness of 200 µm fabri-cated by CANBERA.2) It is partitioned into four active
areas, each of which has 32 columns (z) × 256 rows (φ)
with pixels of 425 µm (z) × 50 µm (φ). For the readoutchip, the ALICE1LHCb readout chips are used, which
is designed using the IBM 0.25 µm CMOS process of
the radiation hardened technology and has a maximum radiation tolerance of up to 30 Mrad. The sizeof the chip is 15.6 mm × 13.7 mm with 150 µm thickness. One chip has 8,192 (32 × 256) input channels,
each of which processes an input signal individually.
A raw signal from each pixel is preampliﬁed and discriminated with conﬁgurable threshold level. The discriminated binary signal is delayed with programmableduration, and then, stored to be read out by a downstream data acquisition system. The chip has 42 internal 8-bit Digital-to-Analog Converters (DACs) for
controlling the threshold of discriminators and various
timings. All conﬁgurations are set via the JTAG serialinterface (IEEE std. 1149.1-1990). The chip is operated using a 10 MHz clock; therefore, the maximum
readout speed is 25.6 µsec/chip with a 32-bit line.3)
Four hundred and eighty ALICE1LHCb readoutchips will be used for the construction of the PHENIX
silicon pixel detector. Because the yield rates of thechips are less than 50%, we have carried out tests
to select fully functional readout chips in the state ofwafer.4) Then, a single sensor and four selected readout chips are interconnected by bump-bonding, andthe same testing procedure is performed. Additionally,functionality tests of the sensor ladder with real signals from the sensors induced by β-rays are performed
to check the total functionalities of the sensor ladder.
These functionality tests are performed at the semiautomatic probe station (SUSS MicroTec Co., Ltd.,
type PA200) at RIKEN (Fig. 2). In these tests, control signals and test pulses are injected into the chipFig. 1. Silicon pixel sensor ladder.
∗

Graduate school of Science and Technology, Niigata University

Fig. 2. Semiautomatic probe station at RIKEN.

207

and digital information is read through thin needles
touching the bonding pads on the readout chip.
Firstly, all chips are classiﬁed according to the following ﬁve conditions to select fully functional chips.
1) The current consumed by the analog circuit mustbe less than 350 mA. The current consumed by thedigital circuit must be less than 270 mA. 2) JTAG
must be functional. 3) The DACs must be suﬃciently
linear; the linearities are conﬁrmed by plotting the responses. 4) The global threshold of the 8,192 channels
must be less than 2,000 e− , which is 1/7 of the typicalsignal caused by a minimum ionizing particle; global
threshold on a chip is adjusted so that the counting
rate without input signal will be suﬃciently low (≤ 1
count/min). Then, output rates are measured by increasing the amplitude of calibrated input pulses. Output rate increases at the threshold level with a ﬁnite
slope. From the central position and slope of the rise,
threshold and noise levels are obtained in the unit ofe− . 5) The number of defect pixels must be less than82; defect is pixels are pixels having no output eventhough a suﬃciently large test signal is injected into
the input.
From the result of the test of the readout chips, thechips are classiﬁed into three classes (Classes 1, 2, 3).
Class-1 chips are deﬁned as chips which satisfy all theabove conditions. They are of good quality for the construction of sensor ladders. Class-2 chips satisfy conditions 1, 2 and 3 only. They can be used for an electricaltest for prototypes. The other chips are classiﬁed as
Class-3 chips. At present, 1,720 chips (20 wafers) havebeen probed. The results are shown in Table 1. We
obtained 605 Class-1 chips (35% of the tested chips),
which is suﬃcient for the construction of the VTX. A
readout chip without a sensor chip has a typical global
threshold of 1,700 e− and a typical noise level of 120e− .
Secondly, using the Class-1 chips, sensor ladders areassembled and the same test is performed. Typically,

the global threshold is 2,700 e− and the standard deviation of the 8,192 channels on one chip is 220 e− . The
mean noise level is 160 e− . It seems that the increase innoise level is due to additional noise from a sensor chip.
The number of electrons induced by the minimum ionizing particles in the silicon sensor with the thicknessof 200 µm is approximately 14,000 e− . Consequently,
the signal-to-noise ratio is approximately 90.
Finally, total functionality, including electrical functionality between a sensor and readout chips is tested
by a β-ray source. An inverse bias of 50 V, which iswell more than the full depletion voltage (∼ 10 V), isapplied to the surface of the sensor using a thin needle.
Then, the sensor is irradiated with β-rays from a 90 Srchecking source and its signals are processed by electrical circuits in a readout chip. The results are shownin Fig. 3. White dots are caused by pixel defects, thecorresponding channels of the readout chips, or the interconnection between readout chip and sensor. Morethan 99% pixels work on the sensor ladder. Currently,
18 sensor ladders have been assembled. Four sensor
ladders have been probed at CERN and 7 sensor ladders have been probed at RIKEN. One sensor ladderof the probed sensor ladders has one broken readoutchip. One sensor ladder of the probed sensor ladders
has more than 1% of missing bump-bondings. Two
sensor ladders of the probed sensor ladders always havenoisy pixels on the chips.
In summary, we have tested the performance of 1,720
chips for the VTX construction. As a result, 605
Class-1 chips were obtained. Eighteen sensor ladders
have been assembled. Eleven sensor ladders have beenprobed. Four sensor ladders of the probed 11 sensor
ladders have defects. By the end of March 2006, we
will obtain 36 sensor ladders. Early in 2006, we will
perform the prototype half-stave5) test. Data-taking
performance and detection eﬃciency will be checkedin the test.
References

Table 1. The result of wafer probing.

1) Y. Akiba et al.: RIKEN Accel. Prog. Rep. 39, 199(2006).
2) V. Manzari et al.: J. Phys. G 30, S1091 (2004).
3) W. Snoeys et al.: Nucl. Instrum. Methods Phys. Res. A
466, 355 (2001).
4) P. Riedler et al.: Nucl. Phys. A 501, 111 (2003).
5) Y. Onuki et al.: RIKEN Accel. Prog. Rep. 39, 205(2006).

Fig. 3. Inter-connection test result of sensor ladder.

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RIKEN Accel. Prog. Rep. 39 (2006)

Development of PHENIX PIXEL bus
A. Taketani, Y. Akiba, J. Asai, H. En’yo, K. Fujii,∗1 K. Fujiwara,∗2 Y. Goto, J. M. Heuser, H. Kano, M. Kogo,∗3
T. Kawasaki,∗2 H. Maeta,∗1 H. Ohnishi, Y. Onuki, M. Tanaka,∗4 M. Sekimoto,∗4 and S. Watanabe∗2
A silicon tracker will be implemeted in the RHIC
PHENIX experiment. The main purpose of this new
detector is to identify heavy ﬂavor quark production in polarized proton collisions and heavy ion collisions by measuring the distant closest approach, sinceheavy ﬂavored mesons have a longer lifetime than lightmesons, which are 100 to 500 µm. We use two diﬀerent sensors in this detector1) : the inner two layers are
pixel sensors and the outer two layers are strip sensors.
The detailed structure of the pixel part is describedin Ref. 2. The signals from the pixel sensor are digitized at readout chips3) and then propagate to the
SPIRO board, which multiplexes 8 readout chips tothe next stage of the DAQ system. The SPIRO board
will be located at the endcap part of the PHENIX detector, which is 40 cm to 60 cm away from the pixel sensors. Hence, ﬁne-pitch ﬂexible printed circuit boards
are used in these connections as readout buses.
The detector is located at the innermost part of the
PHENIX central arm. The material thickness of thedetector should be minimized to avoid electron generation upon photon conversion, and to attain better resolution for distant closest approach mesurements. Also,
the PHENIX DAQ system requires a 20 kHz readout
speed for each subsystem. The pixel part has a totalof 3.9 M channels. Therefore, the readout bus has 196
lines, including 128 parallel data lines, control lines,
reference voltage lines, and sensor bias voltage lines.
The sensor size is 1.55 cm × 5.7 cm, so the bus shouldbe the same width. The thinner part part of the bus
is 25 cm to minimize the material budget in the central detector acceptance region. The reminder of thebus can be slightly thicker, so we can use the industrystandard Cu-polyimide bus, the Cu-extender. These
two types of bus will be connected by wire bonding.
High-density connectors will be used as the connection
between the Cu-extender and the SPIRO board.

In order to satisfy the above requirements, we havebeen developing an Al-polyimide-based bus, because
the radiation length per unit thickness of Al is about
1/6 that of Cu. We established a basic technique of
fabricating the bus and discussed the detailed design
rules4) last year. Then the layout of a 1.5-cm-wide bus
was designed. Unfortunately, the manufacturing company became bankrupt before the Al-polyimide based
bus could actually be fabricated.
For a total electronics test of connecting the sensor hybrid with bump-bonded readout chips, readoutbus, Cu-extender, and SPIRO board, we fabricateda 3 cm Cu-polyimide bus instead of the 1.5 cm Alpolyimide bus. The Cu-polyimide bus can be fabricated by industry-standard technology without R&D
eﬀort. The layout was designed on the basis of theexisting 1.5-cm-wide design. Figure 1 shows the fabricated 3-cm-wide Cu-polyimide bus.
The SPICE model5) is used to evaluate the bus peformance, such as signal propagation, bus impedance,and crosstalk. In this simulation, the bus length is
25 cm, signal lines are 70 µm wide with a 50 µm space,and polyimide ﬁlms among the layers are 50 µm thick.
Figure 2 represents the propagation performance andcross talk. The signal shape at the receiving end isgood enough for GTL-level operation and crosstalk to
adjacent lines is 50 mV, which is much smaller thanthe 0.8 V of GTL H/L logic level diﬀerence. The characteristic impedance is calculated to be 15 to 100 Ω.
We have been developing a readout bus for the
PHENIX pixel detector. It is required to be of ﬁne
pitch and low material budget. We fabricated 3-cmwide bus with Cu and polyimide for electrical test purposes. An Al-polyimide bus has been developed andits performance has been evaluated on the basis of asimulation.

Fig. 1. A 3-cm-wide Cu-polyimide bus.
∗1
∗2
∗3
∗4

Hiroshima Kokusai Gakuin University
Niigata University
Tokyo Metropolitan College of Aeronautical Engineering
High Energy Accelerator Research Organization

209

References
1) Y. Akiba et al.: RIKEN Accel. Prog. Rep. 38, 227(2005).
2) J. M. Heuser et al.: RIKEN Accel. Prog. Rep. 37, 250(2004).
3) K. Fujiwara et al.: RIKEN Accel. Prog. Rep. 38, 228(2005).
4) A. Taketani et al.: RIKEN Accel. Prog. Rep. 38, 233(2005).
5) Avant! Corporation: Star-HSPICE Manual (1988).

Fig. 2. Propagation and crosstalk for Al-polyimide bus.

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RIKEN Accel. Prog. Rep. 39 (2006)

Developments and tests of PHENIX pixel detector
readout system
H. Kano, A. Taketani, H. Ohnishi, Y. Akiba, K. Fujiwara,∗ Y. Onuki, J. Asai, and H. En’yo
The PHENIX experiment is expected to be upgraded in 2009. Several new detector systems will provide extended detection capabilities in heavy-ion andpolarized proton-proton collisions when RHIC reaches
full operation at the designed luminosity in the next
few years. The main PHENIX upgrade involves a new
silicon vertex tracker installed between the pole facesof the central magnet. The silicon vertex tracker consists of pixel and novel microstrip sensors. The pixel
detectors in the inner layer are essential for resolving
the high track densities in heavy-ion collisions.
The block diagram of the PHENIX pixel detector
readout system is shown in Fig. 1. The right-handside shows the electronics located in the control room,
whereas the left-hand side shows the on-detector electronics. Communication between the control room andthe detector is via two optical fibers, one carrying theclock signal, the other carrying trigger, configuration,and control signals. Data transmission from the detector to the control room is performed via a 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 0.25µ CMOS technology using radiationhardening techniques. Precautions have been taken to
reduce malfunction due to single-event upsets. The
digital-pilot ASIC performs the optical-to-electricalconversion of the incoming clock and data signals,
initiates the readout sequence in the readout chips,
and sends data to the 1.6 Gbps Ethernet-like serializer
chip GOL.a) We have modified the digital-pilot ASIC1)
based on the ALICE chip architecture,2,3) which has
an extended data bus width (16-bit to 32-bit) for
PHENIX. The first version of the chip successfully
worked well. Then second version of the chip is designed and fabricated with new features that include
parity check, trigger counter, and additional power/
ground pins for stable operation.
The test system for the digital-pilot ASIC is shownin Fig. 2. The PC sends dummy hit patterns and con-Fig. 2. Picture of PHENIX digital-pilot chip test board.

trol signals to the digital-pilot ASIC via a pulse patterngenerator module, and compares between a dummy
hit pattern and the output of the ASIC using a FIFO
module. In this test for the first version of the chip, all
the functions of the modified digital-pilot ASIC worked
well.
In the PHENIX pixel optical link between the control room and on-detector electronics, a serializer isused to encode 32-bit words in a serial stream. The
stream rate is up to 1.6 Gbps. We developed the test
system with GOL and a Vertex-2 pro FPGA with
8b/10b or CIMT4) encoding (shown in Fig. 3). Thissystem shows a low error rate (< 10−15 ) at 1.6 Gbps
(8b/10b and CIMT). This is the first CIMT link system to be realized at the 1.6 Gbps data rate.
We have been developing the PHENIX pixel readout
system. The first version of the digital-pilot chip was
fabricated and confirmed to work. The second version
was fabricated to achieve stable operation.

Fig. 3. Picture of test system for optical link system.

References

Fig. 1. Block diagram of PHENIX pixel detector readout
system.
∗a)1) H. Kano et al.: RIKEN Accel. Prog. Rep. 38, 237(2005).
2) P. Chochula et al.: Nucl. Phys. A 715, 849 (2003).
3) A. Kluge et al.: CERN 2001-005, 95 (2001).
4) C. Yen et al.: Hewlett-Packard J. Oct. 1992, 736 (1992).

Niigata University
http://proj-gol.web.cern.ch/proj-gol/

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RIKEN Accel. Prog. Rep. 39 (2006)

Development of silicon stripixel detector for PHENIX experimentJ. Tojo, Y. Akiba, J. Asai, A. Deshpande,∗1 H. En’yo, D. E. Fields,∗2 Y. Goto, Z. Li,∗3 and M. Sekimoto∗4
A silicon vertex tracker (VTX) for the PHENIX
experiment in the Brookhaven National Laboratory(BNL) has been proposed for enhancing the physics capabilities of the baseline detector system. An overview
of the PHENIX detector and the VTX upgrade projectis given in Ref. 1 and Ref. 2, respectively. In this article, we report the development of a silicon stripixel
detector for the two outer barrel layers of the VTX.
The silicon stripixel detector has an outstanding feature of two-dimensional position sensitivity only forsingle-sided processing.3) A combined structure of bothpixels and strips is formed on one side of the detector.
The two-dimensional position sensitivity is achieved bycharge-sharing between two interleaved electrodes arranged in each pixel. Collected charges in interleaved
electrodes are projectively read out by strips.
The stripixel detector for the PHENIX experimenthas been designed and prototyped in collaboration
with the BNL Instrumentation Division. We havestudied in detail the performance of the prototype sensors in static electrical tests4) and beam/source tests.5)
On the basis of those studies, we have carried out the
preproduction of the sensors.6) The important developments are the construction of a prototype detector
with the preproduction sensor and a readout electronics with the SVX4 chip7) used in the VTX and theevaluation of detector leakage current, signal-to-noise
ratio (S/N ) and the charge-sharing property.
Figure 1 shows the prototype detector fabricated forthis evaluation. The preproduction sensor integrated

Fig. 1. Photograph of prototype silicon stripixel detector.
∗1
∗2
∗3
∗4

212

Department of Physics and Astronomy, State University of
New York-Stony Brook, USA
Department of Physics and Astronomy, University of New
Mexico, USA
Brookhaven National Laboratory, USA
High Energy Accelerator Research Organization (KEK)in the detector was processed by Hamamatsu Photonics in Japan. The sensor thickness was 625 µm. The
static electrical test of the sensor was performed at
the RIKEN BNL Research Center.8) The sensor was
mounted on a printed circuit board of 2 mm thickness. A part of the sensor backplane was glued tothe base board using a room-temperature curing conductive epoxy (Loctite 3888) to apply a bias voltage. Two electronic hybrids, each of which contained
three SVX4 chips, were used to read out one-halfof the sensor and were mounted on the base board.
The hybrid backplane was glued to the base board
with a room-temperature curing nonconductive epoxy(Araldite 2011). The readout pads on the sensor were
electrically connected to SVX4 chips by wire-bonding
with a 25-µm-diameter aluminum wire. The electronic
hybrids were connected to a prototype control card
and a front-end module compatible with the PHENIXDAQ system.
Total leakage current in the detector with 768
strips wire-bonded to SVX4 chips was measured to be
0.31 µA at an operating temperature of 19.4◦ C and thefull depletion voltage was 120 V, which corresponded
to 0.40 nA per strip on average. The maximum leakage
current per strip acceptable in the PHENIX detector
operation was estimated to be 15 nA, at which leakage
current did not saturate the preampliﬁer of the SVX4
chip with a dynamic range of 200 fC. The measured
leakage current was suﬃciently small to operate thedetector without the preampliﬁer saturation.
The noise performance of the detector was evaluatedby adjusting the preampliﬁer rise time and FET bias
current in SVX4 chips. The gain in SVX4 chips wascalibrated by externally injecting charges to the preampliﬁer. Figure 2 shows a preliminary result for noise
measured in one of the SVX4 chips in the detector.
There was a function of real-time pedestal subtraction(RTPS) implemented in the SVX4 chip to suppress
common mode noise.7) The eﬀect of RTPS is also presented in Fig. 2. The equivalent noise charges deﬁned
by the root-mean-square of the noise, were determined
to be ∼1,050 e− rms with RTPS oﬀ and ∼800 e− rmswith RTPS on. To estimate S/N for minimum ionizing particle (MIP), it was assumed that the signal
readout by each strip consisted of 22,500 electron-holepairs, in which a factor of 1/2 due to charge-sharing
was included. Assuming one MIP signal, S/N values
were estimated to be ∼21 with RTPS oﬀ and ∼28 with
RTPS on. The results showed an excellent noise performance of the detector.
The charge-sharing property was studied by injecting infrared (1060 nm wavelength) pulsed laser light tothe detector. Figure 3 shows a preliminary result of

Fig. 2. (a) Noise value (ADC [ch]) as function of SVX4
channel number with RTPS oﬀ, (b) Noise distribution
for all SVX4 channels in (a), (c) Noise value (ADC [ch])as function of SVX4 channel number with RTPS on, (d)Noise distribution for all SVX4 channels in (c).

collected charges as a function of channel number of
two SVX4 chips. The channel numbers 1–128 correspond to one projective direction of strips (X-strips)
and the channel numbers 129–256 correspond to theother projective direction of strips (U -strips). Twodimensional position sensitivity by charge-sharing is
supposed to be observed as one peak in the X-strip
range and the other peak in the U -strip range. In thepresent laser-ﬁber optic setup, the laser spot size inthe detector was too large to study the charge-sharing
property in detail. A conclusive result for the chargesharing property will be obtained by optimizing laser
spot size or using a radioactive source.
In summary, we developed the prototype silicon
stripixel detector with the preproduction sensor andthe SVX4 chip for the PHENIX experiment. We carried out the detector performance tests of leakage current, noise and the charge-sharing property. The preliminary results showed an excellent performance ofthe detector in terms of leakage current and noise.
Detailed studies including the charge-sharing property
will be performed using an optimized laser setup anda radioactive source.
References
1) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
2) Y. Akiba et al.: RIKEN Accel. Prog. Rep. 39, 199(2006).
3) Z. Li: 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) J. Tojo et al.: RIKEN Accel. Prog. Rep. 38, 231 (2005).
7) B. Krieger et al.: IEEE Trans. Nucl. Sci. 51, 1968
(2004).
8) J. Asai et al.: RIKEN Accel. Prog. Rep. 38, 235 (2005);
RIKEN Accel. Prog. Rep. 39, 203 (2006).

Fig. 3. Collected charges (ADC [ch]) as a function of channel number of two SVX4 chips.

213

RIKEN Accel. Prog. Rep. 39 (2006)

Development of low voltage power supply
for PHENIX PIXEL detector
A. Taketani, Y. Akiba, J. Asai, S. Boose,∗ H. En’yo, K. Fujiwara, H. Kano, H. Ohnishi, and Y. Onuki
The PHENIX experiment at the Relativistic Heavy
Ion Collider will be upgraded with a silicon vertex
track to enhance the heavy ﬂavor identiﬁcation capability.1) The inner two layers will consist of pixel sensors. Signals will be read by bump-bonded readoutchips,2) which include the preampliﬁer, shaper, discriminator, and digital event buﬀers. The thicknessof the pixel sensor is 200 µm. The amount of signal
charge deposited by the typical minimum ionizing particle is about 2 fc and is integraded over 30 nsec. Hence,
the readout system must have a low-noise low-voltage
power supply. Because a similar pixel detector at theNA60 experiment has been operated with a power supply with 5 mVrms noise, our tentative target is thesame level. There are 60 electrically independent halfstaves, which consist of two sensor hybrids and a readout bus.3) Half staves are operated at 1.8 V and 3.1 A.
We can adjust the voltage supplied to each individual
half stave, and turn them on/oﬀ in the case of resetting/removing the individual half staves. Therefore,
we need 60 individual power supplies for the PIXEL
low-voltage power supply. We speciﬁed the requirements of the PIXEL low-voltage power supply, fabricated a trial working power supply and then evaluatedthe performance.
In addition to the number of channels, supply voltage, current, and noise ﬁgure, this power supply has
various other requirements, because it will be installed
2 to 4 m away from the pixel detectors. Because thevoltage drop along the long supply conductor is notappreciable, voltage sensing using another smaller wire
should be implemented to stabilize the voltage.
Figure 1 shows a block diagram of the power supply.
A Base Power Supply (BPS) feeds DC 5 V to individual Unit Power Modules (UPMs). Then the UPMs will
convert 5 V to 1.8 V using a 3-terminal regulator with
voltage sensing, which is connected to the load. A PC
is connected to a Control and Monitor Unit (CMU)
and controls the turning on/oﬀ of the BPS and each
UPM. The drawing current can be monitored. These
control and monitor functions will be implemented using ADAM 5000 remote I/O modules,4) which are currently used for the PHENIX low-voltage power supply
control and monitoring system.5) The turning on/oﬀ
will be controlled by the relay, and the current will bemonitored by the voltage across the shunt register at
the UPM output circuit. The UPM should be a card
module with connectors at the front and back for easy
maintenance.
A trial power supply is built and tested. The∗

214

Brookhaven Natinal Laboratory, USA

Fig. 1. Block diagram of power supply.

Blenix6) BLN ultra low-noise AC/DC switching power
supply is used as the BPS. Figure 2 shows a photograph of the UPM. The noise is at the 3 mVp-p level.
Remote control and monitoring functions are implemented and tested. The UPM size is 15 cm × 10 cm
per output, which is suﬃciently small.
The low-voltage power supply for the PHENIXPIXEL detector is designed and fabricated for trial.
It is found to satisfy the initial requirements.

Fig. 2. Photograph of power supply.

References
1) Y. Akiba et al.: RIKEN Accel. Prog. Rep. 38, 227(2005).
2) K. Fujiwara et al.: RIKEN Accel. Prog. Rep. 38, 228(2005).

3) A. Taketani et al.: RIKEN Accel. Prog. Rep. 38, 233(2005).
4) ADVANTECH, http://www.advantech.com/

5) S. S. Adler et al.: Nucl. Instrum. Methods Phys. Res.
A 499, 560 (2003).
6) Bellnix Co., Ltd.: http://www.bellnix.com/

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Optical alignment system for PHENIX muon tracker
H. Kanoh,∗1 A. Taketani, T.-A. Shibata,∗1 N. Kamihara,∗1 and M. J. Kweon∗2
The muon tracker of PHENIX is placed in the muon
magnet and it has three layers of tracking chambers
called stations. By tracking a muon that is bent witha magnetic ﬁeld, the momenta of muons are measured.
The momentum resolution of the muon tracker is determined by the chamber spatial resolution and accuracyof the relative position among stations. The spatial
resolution is approximately 70 µm to 100 µm per station. This value is required to separate ψ  mesons fromJ/ψ mesons in dimuon events. We align the position
among the three stations using the ﬁeld-oﬀ event dataat the beginning of the run period. However, eachstation was moved 100–300 µm by the magnetic ﬁeld
and temperature ﬂuctuation during the experiment period. To improve the momentum resolution, we should
correct these relative movements. The purpose of the
optical alignment system (OASYS)1) is the real-timemonitoring of the relative alignment among the stations. In the present data analysis, the data from the
OASYS was not taken into consideration for the position aligment of the tracking chamber, and mass resolution does not yet have a design value.
The OASYS consists of a light source at station 1, aconvex lens at station 2, and a CCD camera at station
3. When an individual station moves, the image on
the CCD camera moves, reﬂecting the station movement. A similar alignment system was used in the L3experiment at LEP.2) Each station is separated into
eight segments called an “octant”, and there are 7 setsof optics on each octant. There are 7 (optics/octant)× 8 (octant/arm) × 2 (arm) = 112 optics in total.
By observing the position of the light spot on the image of the CCD camera, we can monitor each station’s
movement.
To establish a relative alignment method using the
OASYS, we studied the tracking chamber’s relative
movement. We assume that the tracking chamber
is a rigid body, and we model the movement of the
tracking chamber with parallel translation and rotation. It is impossible to calculate all of the movementsof the three stations from only the information of the
OASYS. However, we can assume that station 1 does
not change its position, because only the relative position among stations is essential for absolute measurement. Station 1 is chosen as the relative position reference.
We deﬁne the octant local coordinate system. The
origin is deﬁned as the collision point. The z-axis isdeﬁned along the beam, and the north arm is selected
as the positive direction. The y-axis is deﬁned along
∗1
∗2

216

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

the centerline of the octant, and the x-axis is deﬁned
as perpendicular to the y-axis.
First, we discuss the relationships of image movement and optics movement. The movement of the image on the CCD camera δximg is described by theandmovements of station 2 and station 3, δxtotal2
δxtotal:3δximg =

1 
(l1 + l2 )δxtotal,− l1 δxtotal
2
3
l1

(1)

where l1 and l2 are intervals between the stations, as
shown in Fig. 1. Next, we will describe the octant’s
movement with parallel translation and rotation. We
deﬁne three component vectors δxs , which express theoctant’s parallel translation.
δxs = (δxs , δys , δzs )(2)Here, “s” denotes the index number of the stations(s = 1, 2, 3). Then, we also deﬁne matrix Rs , which
expresses the rotation of the chamber around x, y andz axes using three parameters δφx,s , δφy,s and δφz,s .
Actually, δφi,s (i = x, y, z) is on the order of 10−3
to 10−4 [rad] and is much smaller than 1, because theinterval between the stations is on the order of meters
and the movement of the tracking chamber is on theorder of several hundreds of micrometers. Therefore,
we give the following approximation.
cos δφi,s  1, sin δφi,s  δφi,s (i = x, y, z)(3)Then, rotation matrix Rs is deﬁned as follows.
Rs ≡ 1 + εs0εs ≡ ε(δφs ) ≡  δφz,s−δφy,s−δφz,s
0
δφx,s



δφy,s
−δφx,s 
0

(4)
(5)

We select the cross point of the octant plane and beam
pipe as rotation center z0,s = (0, 0, z0,s ). The movement due to the rotation of station “s” δxrotate,s atposition xs is expressed asδxrotate,s = Rs x̂s − x̂s= εs x̂s ,Fig. 1. Cross section of the muon tracker.

(6)where x̂s ≡ xs − z0,s . From Eqs. (2) and (6), total
optics’ movement is written as≡ δxs + εs x̂s .
δxtotals(7)Then, the movement of the image is written as follows
using Eqs. (1) and (7).
1 
(l1 + l2 )δxtotal− l1 δxtotal
2
3
l1
1
=
{(l1 + l2 )δx2 − l1 δx3 }l1
1+ {(l1 + l2 )ε2 x̂2 − l1 ε3 x̂3 }l1

δximg =

(8)

Optics are aligned in a straight line. Therefore, vectorx̂3 is approximately proportional to vector x̂2 , becauseof their geometrical relationships:x̂3 = αx̂2 ,(9)where α = z0,3 /z0,2 . Using Eqs. (8) and (9), δximg iswitten as1
δximg ={(l1 + l2 )δx2 − l1 δx3 }l1
1+ {(l1 + l2 )ε2 − αl1 ε3 } x̂2 .
(10)
l1

Fig. 2. Time-dependent movement during run 03.
δx (left upper), δy (left middle), δz (left lower) and δφx(right upper), δφy (right middle), δφz (right lower).

Here, we deﬁne x2 and δφi,2 from xi and δφi,s ,l1
δx3
l1 + l2l1
δφi,2 ≡ δφi,2 − αδφi,3 (i = x, y, z),
l1 + l2
δx2 ≡ δx2 −

(11)
(12)

and δximg becomesδximg =

l1 + l2  
δx2 + ε(δφ2 )x̂2 .
l1

(13)

In Eqs. (11) and (12), we cannot distinguish the movement of station 2 from that of station 3 using OASYS,
and they are mixed. However, only station 2 appears
to be moving in Eq. (13). This means that we canapproximate that only the central station (station 2)
moves. The movement of the image on the CCD camera and the movement of the tracking chamber correspond one to one in Eq. (13), and we can calculate themovement of the tracking chamber from the movementof the image analytically.3)
As a result of analysis with data obtained in therun 3 experiment period, we calculate the movementof the tracking chamber in the north muon arm. For
example, the result of octant 3 is shown in Fig. 2. The
vertical axis is the displacement from the initial value
and the horizontal axis is time. Each tracking chamber
has moved by 50 µm to 300 µm during the experimentperiod. We can correct the relative movement of the
tracking chamber using our model, and the accuracyof alignment has become less than 40 µm. This value
is better than the required accuracy.

The correlation of the mass resolution of J/ψ mesons
and the accuracy of alignment by OASYS was estimated using Monte Carlo simulation, as shown in
Fig. 3. The horizontal axis is the accuracy of alignment in micrometers and the vertical axis is the mass
resolution in MeV. The accuracy of better than 50 µm
is required to separate ψ  well and it is achieved in our
analysis method.

Fig. 3. Alignment accuracy dependence of J/ψ mass resolution, estimated by MC simulation.

References
1) J. Murata et al.: Nucl. Instrum. Methods Phys. Res. A
500, 309 (2003).
2) B. Adeva et al.: Nucl. Instrum. Methods Phys. Res. A
289, 335 (1990).
3) H. Kanoh: Master thesis, Tokyo Institute of Technology(2004).

217

RIKEN Accel. Prog. Rep. 39 (2006)

Experimental status of penta quark search via K + p → π + X reaction
at KEK-PS E559
K. Miwa,∗ for the E559 Collaboration
Since the report on the evidence of an exotic baryon
Θ+ ,1) many studies from both theoretical and experimental aspects have been conduced. The observation at SPring-8/LEPS was immediately conﬁrmed byseveral experiments.2) Recently, however, null results
have been reported from several high-energy experiments where investigators searched for Θ+ using higher
statistics.2) Therefore, in such a situation, the conﬁrmation of Θ+ is urgent and crucial.
We have performed an experiment to search for Θ+
via the K + p → π + X reaction at the K6 beam linewith high statistics and good missing mass resolution
using the SKS spectrometer at KEK 12 GeV Proton
Synchrotron (KEK-PS E559). The best missing mass
resolution of 2.35 MeV/c2 (FWHM) is expected. Oneof the most important purposes is the determinationof the width of Θ+ , if we observe Θ+ . As a target,
a 12.5-cm-long liquid hydrogen was used. We used
the K + beam of 1.2 GeV/c. The typical intensity was
14k counts during the 2 seconds of spill. K + was selected using an aerogel cherenkov counter at a trigger level. In the oﬄine analysis, K + was selected using the time-of-ﬂight information. The momentum ofeach beam particle was analyzed using the K6 beamline spectrometer of which the resolution is expected
to be ∆p/p = 0.047% (FWHM). Scattered particles
were detected using the SKS spectrometer.
The setup around the target is shown in Fig. 1.
The main background of the measurement is the 3
body decay of K + such as K + → π + π + π − or K + →π + π 0 π 0 . The rejection of these decay backgrounds isessential for the Θ+ search. In decay events, one or
three charged particles are emitted to a forward angle,
whereas in a hadoronic reaction such as ∆ productionor Θ+ production, two charged particles are emittedwith a large scattered angle. Therefore, we installeda large acceptance chamber after the target to detect
the charged particles. We selected two charged particle

events to reject decay events. To improve S/N ratio bydetecting K + , we also installed a range counter systemat the downstream of this chamber.
The analysis was done using RIKEN-CCJ. For thecalibration of the system, we analyzed H(π + , K + )data to measure Σ+ . We checked the missing mass
resolution from the Σ+ peak width and the eﬃciencies
of detectors and oﬄine analysis from the yield of Σ+ .
The yield of Σ+ is approximately 1050, which is 70% of
the expected yield. The width of Σ+ obtained from themissing mass spectrum is 2.35 MeV/c2 (FWHM) which
is worse than the expected resolution of 1.57 MeV/c2 .
This might be caused by an insuﬃcient ﬁeld map. For
Θ+ search, the missing mass resolution is evaluated tobe 3.22 MeV/c2 in the present analysis.
Let me now describe the present analysis status of(K + , π + ) data. The vertex distribution after the rejection of decay events is shown in Fig. 2 with the
distribution of the empty target data (hatched histogram). The 125 mm liquid hydrogen image is clearlyobserved. We took approximately 14,000 reaction
events of K + p → π + X. The cross section of this reaction is 5.3 mb3) and the present yield is about 85% of
the expected one. Therefore our analysis is going well.
However, there are many background events which isshown in the hatched histogram in Fig. 2. These eventsmight be the contaminations of the K + decay eventsand reaction events at the timing counter upstreamof the target (BH2). For example, π + from the decays of KS0 produced by the K + n → K 0 p reaction
can make such broad distribution. We will compare
the vertex distribution attributed to these background
events with a simulation in future studies.
The analysis of (K + , π + ) reaction is still preliminary
and the analysis of the missing mass is in progress.

Fig. 2. Vertex distribution of K + p → π + X reaction.

References
Fig. 1. Experimental setup around the LH2 target.
∗

218

Department of Physics, Kyoto University

1) T. Nakano et al.: Phys. Rev. Lett. 91, 012002 (2003).
2) K. H. Hicks: Prog. Part. Nucl. Phys. 55, 647 (2005).
3) R. W. Bland et al.: Nucl. Phys. B 13, 595 (1969).

RIKEN Accel. Prog. Rep. 39 (2006)

Vector meson measurements at J-PARC 50-GeV PS
S. Yokkaichi
The spontaneous braking of chiral symmetry plays
an essential role in QCD. The constituent light quark
mass in hadrons is due to this symmetry braking. In
hot/dense matter, the symmetry is expected to be restored and the spectral properties of hadrons such as
the mass and the decay width are also expected tobe modified in consequence of this restoration. There
have been many theoretical approaches to this subject1) and some experiments have already suggested
the modification of hadrons in nuclear matter. The
KEK-PS E325 experiment, performed by a group including the author, is one of such experiments. We
have reported the spectral modification in a e+ e− decay channel, ρ/ω mesons2) and even φ meson3) for the
first time.
We intend to perform a next-generation experiment,
the measurement of electron pairs from the decay of
low-mass vector mesons (ρ/ω/φ) in nuclear matter at
the J-PARC4) 50-GeV proton synchrotron. The firstbeam of the 50-GeV PS will be available in JFY 2008.
Around 30 Letters of Intent to use the 50-GeV PS including ours were already submitted. Our proposal5)
was selected as one of the Phase-1 experiments.
The goal of our new experiment is to collect the φmesons in ∼100 times as high statistics as that of theE325 experiment in 30 days of operation with comparable (∼10 MeV/c2 ) or improved mass resolution.
Such measurements enable us to discuss whether theorigin of the observed spectral modification is due tothe chiral symmetry restoration or not, by qualitative
comparison with many of the theoretical predictions.
Several experimental characteristics of E325 are also
followed and/or broadened in the new experiment;these are essential in measuring the modification:• Production of vector mesons in the target nuclei
and observation of the decay of mesons in the target nucleus itself, at the normal nuclear density.
• Although ρ and ω cannot be distinguished in thee+ e− channel because the spectra are overlapped,
φ is isolated and easier to analyze.
• Observation of invariant mass spectra of vector
mesons in the e+ e− decay channel to reduce thespectral distortion by final-state interaction in the
nuclear matter.
• Observation of slowly moving mesons in the laboratory frame to enhance the probability of decay
inside nuclei. The typical βγ (= p/m) of mesons
is less than two.
• Good mass resolution (less than ∼10 MeV/c2 ) to
observe the small modification of φ mesons.
• Use of a high-intensity incident beam to compensate for the very small branching ratio to thee+ e− channel (φ: 2.96 × 10−4 , ρ: 4.54 × 10−5 , ω:6.95 × 10−5 ) and small target thickness (∼0.1%
interaction length) to reduce the background dueto the γ conversions in the target material.
Many other experiments6) fro measuring dilepton
spectra seem to be unable to satisfy one (or more) of
the above conditions. In the completed experiments,
CERES at SPS collected statistics that were too small
to observe the φ meson modifications. NA60 at SPS
has higher statistics than E325, but worse mass resolution (more than 20 MeV/c2 for φ). In the running
experiments, both HADES at GSI and CLAS at JLabseem to have lower statistics and worse mass resolution than E325 for the time being; however, they may
achieve the same level as E325 with possible improvements within the next few years. As a result, E325 is(and will be) a best experiment for measuring the φmodification, at least for several years, till our new experiment is conducted. In future experiments, CBM at
GSI/FAIR is designed to cover the relatively more forward regions than that of our new experiment. Thus
the statistics of slowly moving φ they could collect will
be lower than that of our new experiment by a certain
order of magnitude.
To collect ∼100 times as high statistics as E325, weplan to construct a new spectrometer and to use theprimary proton beam (30 or 50 GeV) at an intensity of
1 × 1010 pps from the 50-GeV PS. In the expected factor of a hundred, about a factor of two is provided by
the increase in the production cross section of φ witha higher incident energy, about five is provided by thelarger coverage of the planned spectrometer, and remaining factor of ten is from the higher intensity of
the incident beam. To cover the larger acceptanceand to cope with the higher interaction rate, R&D
of new technology such as a Hadron Blind Detector(HBD) to electron identification and a tracker with a
Gas Electron Multiplier (GEM) is ongoing as shown in
the Ref. 7. For the detector simulation for designing
the new spectrometer, RIKEN-CCJ is used.
References
1) T. Hatsuda and T. Kunihiro: Phys. Rep. 247, 221(1994), etc.
2) K. Ozawa et al.: Phys. Rev. Lett. 86, 5019 (2001); M.
Naruki et al.: Phys. Rev. Lett. 96, 092301 (2006).
3) R. Muto et al.: nucl-ex/0511019
4) http://jkj.tokai.jaeri.go.jp/
5) http://www-ps.kek.jp/jhf-np/LOIlist/LOIlist.html
6) I. Tserrya: Euro. Phys. J. C 43, 399 (2005).
7) A. Frankel et al.: Nucl. Instrum. Methods Phys. Res. A
546, 466 (2005).

219

RIKEN Accel. Prog. Rep. 39 (2006)

Mass data processing for RHIC-PHENIX experiment
H. Torii, K. Aoki,∗1 F. Ellinghaus,∗2 K. O. Eyser,∗3 C. Hagemann,∗4 R. Han,∗5 T. Ichihara, S. Kametani,
A. Kral,∗6 T. Liska,∗6 P. Mikes,∗7 A. Morreale,∗3 J. Seele,∗2 M. Stepanov,∗8 S. Yokkaichi, I. Younus,∗4
Y. Watanabe, for the PHENIX Collaboration
The entire system of the PHENIX1) detectors consists of various detectors of which the number of channels varies from one hundred to sixty thousand. Signals from all the channels are digitized in front-end
electronics, collected through the PHENIX data acquisition system,2) and recorded in the PHENIX raw data
format (PRDF). In oﬀ-line analysis,3) it is critical toreconstruct the properties of detected particles, for example, momentum and energy, from the raw data. The
information reconstructed from the PRDF is stored ina data summary table (DST) ﬁle. During 2005, we accumulated 260 TB of PRDF ﬁles, which corresponds toan overall luminosity of 3.78 pb−1 , in polarized protonand proton collisions. The PRDF ﬁles were also transferred4) to a high-performance storage system (HPSS)
at RIKEN. The processing of such mass data and its
technique are unique in the world. Here, we will report
the technical highlights of this data processing.
Our goal is to reconstruct DSTs from PRDFs andto transfer back the outputs into the RHIC computing facility (RCF) at Brookhaven National Laboratory (BNL). Figure 1 shows a schematic view of thedata stream. First of all, 25 PRDF ﬁles are transfered from HPSS into a local disk of the Linux machine at the RIKEN super-combined cluster (RSCC).
For each 25 ﬁle, we run reconstruction programs basedon ROOT,a) an object-oriented analysis framework developed at CERN. The outputs of DSTs and smaller
DSTs, named nano-DSTs, are saved back into HPSS.
We have 20 diﬀerent types of nano-DSTs, which contain only the information selected for the purpose of
speciﬁc physics analysis and with diﬀerent triggers.
For each type, we aggregate 25 nano-DST ﬁles, which
are from 25 PRDF ﬁles, into one ﬁle. The aggregatednano-DST ﬁle for each type is transfered to HPSS andthe network ﬁle system (NFS). Then, we transfer themto RCF by bbftp,b) a ﬁle transfer software optimized
for large ﬁles, and to dCache,c) a mass data storage
system. The Load Sharing Facility (LSF) system wasadopted to manage the schedule of all the sequential
steps. It took about 30 hours to process one cycle.
∗1
∗2
∗3
∗4
∗5
∗6
∗7
∗8
a)
b)
c)

220

Kyoto University
University of Colorado, USA
University of California, USA
University of New Mexico, USA
Peking University, China
Czech Technical University, Czech RepublicCharles University, Czech Republic
New Mexico State University, USA
See http://root.cern.ch
See http://doc.in2p3.fr/bbftp
See http://www.dcache.org

Fig. 1. Schematic drawing of the mass data stream. See
text for details.

We used 128 Linux machines of the RSCC system inparallel.
Results of the PHENIX online system3) together
with the status of the data acquisition system werestored in a PostgreSQL database at RCF. Since they
are very important in the reconstruction process, thedatabase was copied into a server at RIKEN every day
or every week during data processing. In order to ensure that the reconstruction was performed with thelatest copy, we kept a time stamp of the copy that wasused for each DST and nano-DST.
We ran a maintenance macro periodically to detect
failure of the entire cycle. The macro checked that 1)
all 25 PRDFs were reconstructed properly, 2) aggregated nano-DSTs were transfered properly to HPSS,and 3) aggregated nano-DSTs were transferred properly to RCF. When the macro detected a failure, thereconstruction and aggregation were performed again.
Since some PRDFs were obtained with a special settingof the trigger, some aggregated nano-DSTs exceeded
the 2 GB limitation of the ﬁle system. We divided 25

PRDFs into 2 or 3 sets in such a case of failure. For
nano-DSTs tagged as good by the maintenance macro,
we ran a quality assurance program in order to checkthe aggregated nano-DSTs. The program evaluatedhistograms that were created during the reconstruction and put the results into a database that could be
utilized later in physics analysis.
In order to maintain the production constant over along period, it is important to monitor the entire process frequently. We formed monitoring shifts among
us to cover 24 hours per day. One monitor living inJapan covers 12 hours, and the other in USA covers
the other 12 hours. Figure 2 shows an example ofthe monitoring windows distributed on a web server,which the monitors checked every three hours, 4 times
per day. The reconstruction speed shown in Fig. 2 (a)is very important since it is sensitive to HPSS access.
Figure 2 (b) shows the transfer speed from RIKEN to
BNL. If the speed drops to less than 1 MB/sec, trouble may have arisen on the internet network between
RIKEN and BNL. Since these ﬁgures were updated
every 5 minutes, we can judge that the drop recorded
in Fig. 2 (b) was a short drop over a couple of hours.
An electric log book, ELOG,d) was employed to reportany observed irregularity. When at least one of themonitoring windows is out of range typically for morethan 6 hours, we enter a message on the ELOG andthen call an expert. In the case of monitors in theUSA, we send an e-mail to the cell phone of the expert
instead of making an international telephone call.

From 260 TB of PRDFs, 42 TB DST and 26 TB
nano-DSTs were produced during the reconstruction,and 22 TB aggregated nano-DSTs in total were transferred to RCF. The process speed was limited by the
speed of transfer from and to HPSS. The transfer
speed was 45 MB/s on average, which was lower than
the theoretical estimate. This may be attributed to
the fact that requests for diﬀerent PRDFs occurred
regardless of the physical ordering of the PRDFs on
the HPSS tape. For the future, there is room to improve the speed by managing the requests according
to the ordering in the tape. Figure 3 shows a historyof the amount of processed PRDF per day after Jun
10th, 2005, when we started this process. Except forsome trouble midway, such as that due to a crash of thehard disk, we succeeded in keeping the process speed
constant for almost three months.
In summary, we successfully ﬁnished the data processing of the PHENIX raw data of 260 TB at RSCC
and sent 22 TB of the output back to RCF. Since thesize and processing time were huge, we collaborated
internationally in order to maintain the process. We
suceeded in processing the mass data in three months.

Fig. 3. Data production speed (left axis) and total size ofprocesssed data (right axis). The total size of PHENIX
raw data, 260 TB, is shown as “Goal.”

References
Fig. 2. Monitoring window of (a) production speed for DST+ nano-DST (filled hist) and DST only (line), (b) transfer speed from RIKEN to RCF (filled hist) and from
RCF to dCache (line) in units of MB/sec as a functionof time in a unit time of one hour. These diagrams weretaken from the web page for monitoring on July 15th,
2005.

d)

1) K. Adcox et al.: Nucl. Instrum. Methods Phys. Res. A
499, 469 (2003).
2) S. S. Adler et al.: Nucl. Instrum. Methods Phys. Res.
A 499, 560 (2003).
3) S. S. Adler et al.: Nucl. Instrum. Methods Phys. Res.
A 499, 593 (2003).
4) Y. Watanabe et al.: RIKEN Accel. Prog. Rep. 39, 222(2006).

See http://midas.psi.ch/elog

221

RIKEN Accel. Prog. Rep. 39 (2006)

Large-scale data transfer in realtime over the PacificY. Watanabe, M. Chiu,∗1 H. Hiejima,∗1 T. Ichihara, S. Kametani, M. L. Purschke,∗2 S. Yokkaichi, and D. Yu∗2
In October 2004, one decision was made that all pp
collision data produced at the PHENIX detector in thenext experiment (Run 5) will be transferred and analyzed at CCJ as soon as possible. This is because thecomputing resources of the RHIC Computer Facility(RCF) at Brookhaven National Laboratory (BNL) are
expected to be fully occupied for more than one year
analyzing the heavy-ion collision data produced in thelast experiment (Run 4) and Run 5, and there is noroom for the pp data. However, a delay in getting theresults is a very serious problem for us (the spin physics
group).
The expected volume of the pp data was 300 TB∼ 500 TB in two months, which required a sustainedtransfer bandwidth of 60 MB/s ∼ 100 MB/s between
BNL and RIKEN. There were two technical options:
One was a well-established method of transportingtape cartridges via airplanes (Fig. 1), and the otherwas transfer via the network. We had already experienced more than 10 MB/s sustained data transfer andexpected to achieve about 40 MB/s with a minor upgrading of the former method. There are several disadvantages of the former method as follows:• It requires much manpower to handle cartridges,
which means that it cannot be achieved by a fully
automated operation.
• It takes more than one week to be ready for analysis at CCJ even when using the fastest transfer
system via airplanes.

Fig. 1. A container stores up to 60 tape cartridges(200 GB/cartridge). The transfer of a ﬁlled up container (12 TB) in one week means a sustained transfer
of about 20 MB/s.
∗1
∗2

222

University of Illinois, USA
Brookhaven National Laboratory, USA

In the latter method, although the network bandwidth
between BNL and RIKEN had already reached about
100 MB/s, we had a slower transfer experience (∼5 MB/s) of actual data using “bbFTP”.1) It means thatmuch improvement is expected for global-scale datatransfer using suitable software. Indeed, it is highly
advantageous to obtain actual data immediately after
the experiment at the opposite side of the globe.
Thanks to Dantong Yu who succeeded in transferring test data of about 70 MB/s between BNL and
CERN, we also easily achieved the transfer of about
70 MB/s between BNL and RIKEN using “GridFTP”.
2)
We decided to use the network transfer as the ﬁrst
option and the transfer via airplanes as the backup(Fig. 2). A NAT equipment (ccjexp) is needed to set
between a global address area and a private address
area, on which storage PCs of PHENIX DAQ system(‘phnxbox’ 1 ∼ 6) are placed. We prepared four PCs(‘ccjbox’ 1 ∼ 4) as the buﬀer for received data at CCJ,
each of which has two disks (2 TB×2).
Each transfer period is separated by disks of the‘Buﬀerbox’es of the PHENIX DAQ system. PHENIX
shift crews initiated the transfer of all data ﬁles in thedisk to the ‘ccjbox’es at CCJ when a disk was ﬁlled
up. On the other hand, when a disk of the ‘ccjbox’es
is nearly full which is poured data from BNL as the
buﬀer, the buﬀer is switched to another disk and starts
to transfer data to CCJ-HPSS from the previous buﬀer
disk automatically.
The actual data transfer was started in early April,
immediately after the beginning of the pp collision experiment. The transfer rate is generally more thanFig. 2. ESNET3) and SINET,4) which are connected to
BNL and RIKEN, respectively, have a junction in New
York. The bottleneck of the route is 1 Gbps between
RIKEN and the University of Tokyo, in which a nodeof SuperSINET5) is placed.

50 MB/s as shown in Fig. 3. To achieve the rate, somekernel parameters related the network conﬁguration in/etc/sysctl were tuned to optimize the transfer speed.
Fortunately, we encountered only some minor problems during the 11 weeks of the experiment period,
such as a few network troubles and one disk failure;otherwise, we succeeded in transferring 260 TB of datausing only the network shown in Fig. 4. It is noteworthy that the transfer project was completed only twodays after the end of Run 5. We may say that it was
nearly “Realtime transfer”. This accomplishment was
mentioned in “CERN Courier”: “This seems to be theﬁrst time that a data transfer of such magnitude wassustained over many weeks in actual production”.6)
We replaced the ﬁle system of the ‘ccjbox’es fromext3 (defacto standard of LINUX) to xfs7) in theearly stage of the transfer project. Both ﬁle systems
had no problems except for reading ﬁles written with
GridFTP and/or bbFTP. The speed of reading ﬁlesfrom the ext3 ﬁle system was about 10 MB/s and it wasFig. 4. Transfer rate (bar graph: in TB/day) and aggregated volume (line graph: in TB). The transfer project
was completed only two days after the end of the experiment.

three times slower than that from xfs. The techniqueused by both GridFTP and bbFTP, may be ill-suitedfor the ext3 ﬁle system. We considered that by thistechnique, many small fragments of a ﬁle are transferred simultaneously with multistreams and eventually reconstructed in a ﬁle at the destination.
References

Fig. 3. Typical transfer rate history measured at RIKEN.
The rate variation is caused by many factors such as
network trouble/congestion, buﬀer trouble and statusof the experiment.

1) http://doc.in2p3.fr/bbftp/
2) http://www.globus.org/grid software/data/gridftp.php
3) http://www.es.net/
4) http://www.sinet.jp/english/index.html
5) http://www.sinet.jp/english/super sinet.html
6) http://www.cerncourier.com/main/article/45/7/15
7) http://oss.sgi.com/projects/xfs/

223

RIKEN Accel. Prog. Rep. 39 (2006)

CCJ operation in 2004–2005
S. Kametani, H. En’yo, Y. Goto, H. Hamagaki,∗ T. Ichihara, Y. Watanabe, and S. Yokkaichi
RIKEN PHENIX Computing Center in Japan(RIKEN CCJ) is a large-scale computing system
mainly for the analysis of RHIC-BNL1) physics: thestudy of the spin structure of a nucleon and QGP
search. CCJ performs the role as the simulation center, the Asian regional computing and the productionof Data Summary Tape (DST) from experimental raw
data in PHENIX.2)
CCJ is composed of calculation nodes, a massstorage system, a medium-scale storage system using
RAID, and a networking system that connects thesecomponents to each another. These systems are installed in the main research building with a coolingsystem and uninterruptible power supplies. The system is integrated with RIKEN Super Combined Cluster (RSCC) of Advanced Center for Computing andCommunication.a) RSCC and CCJ share the massstorage system, and one-eighth of RSCC calculation
nodes are dedicated to CCJ. Users can access CCJ
from an outside network only via two SSH servers, one
operated by Solaris and the other by Linux.
All the 166 calculation nodes of CCJ and 128 nodes
of RSCC have dual CPUs (Intel Pentium III 700 MHz–
1.4 GHz and Intel Pentium4 2.0 GHz for CCJ, Intel
Xeon 3.06 GHz for RSCC), 1(CCJ)/2(RSCC) GByte ofmemory, 2 GByte of swap and 10–100 GBytes of local
work area. The operating system was migrated from
Redhat 8.0 to Scientiﬁc Linux 3.0.3 in March and October 2005 to follow up the PHENIX analysis framework
installed at RHIC Computing Facility (RCF). CPU allocation is performed using the batch job system. CCJ
is adopting LSF3) as the batch job system. RSCC
adopts NEC’s NQSII/ERSII. However, NQS is not designed well for our use in experimental nuclear physics,
e.g., to process thousands of tasks per day. As the redundancy of NQS is also worse than that of LSF, LSF
is employed also for RSCC nodes dedicated to CCJ.
CCJ includes service nodes locally. The user directory and the PHENIX analysis library are stored in
RAIDs and are shared by all the CCJ and RSCC calculation nodes with NFS. The PHENIX library is mirrored once a day through OpenAFS with two Linuxservers (dual Xeon 2.6/2.4 GHz and 1/2 GByte memory). The mirrored library is also exported to otherdomestic collaborators with rsync. Following the shiftof the calibration database architecture of PHENIX
from Objectivity/DB to PostgreSQL in 2004, the local service of PostgreSQL on CCJ has been started.
The backup of the PHENIX database is copied to CCJ
once a day. The local database service is managed on
∗
a)

224

Center for Nuclear Study, Graduate School of Science, University of Tokyo
http://accc.riken.jp

the Linux server whose performance is suﬃciently high(Xeon 3.0 GHz, 2 GByte memory).
The mass storage system has a capacity of 0.8 PByte
using 4000 cartridges of tapes with a 200 GByte size
each. The cartridges are handled by the StrageTek
PowerHorn 9310 tape robot system and eight 9940B
tape drives which read/write tape with 30 MBytes/sec.
These manipulations and data accesses are managed
by the High Performance Storage System (HPSS)4) 4.5
on ﬁve IBM p630 with AIX. The mass storage systemstores PHENIX raw experimental data (all the p +p experiments for all the year, heavy-ion experiment
for the ﬁrst and second years), DST (the same as raw
data), compact DST called nDST (all the year bothfor p + p experiments and heavy-ion experiments) anduser analysis data archives.
The medium-scale storage system decreases loads onthe mass storage system. The system includes ﬁve
SUN machines and three Linux machines connected
to RAID systems with the Fiber Channel (FC) interface. The total capacity of the RAIDs was 28.6 TBytes
in April 2005. As that volume is not suﬃcient, thebuﬀer system of RIKEN-BNL data transfer system(3.8 TBytes) is temporarily diverted into the mediumscale storage system.
These systems are connected with the Gigabit
Switch Network with Cisco Catalyst 4506 for fast I/O.
The connection for service nodes is 1000Base-SX andthat for calculation nodes is 100Base-T.
The main activities of CCJ in 2004–2005 were thetransfer of raw data of PHENIX ﬁfth-year p + p experiment, the DST production for the fourth- and ﬁfthyear p + p experimental data and the spin analysisof the ﬁfth-year experimental data. The ﬁrst activity,
raw data transfer from BNL to RIKEN, was achieved
during the ﬁfth-year experiment. About 270 TByte
data were transferred with GridFTP simultaneouslywith the experiment. Details are described in this volume.5) For this purpose, four RAIDs and servers are
introduced as a buﬀer system before transferring data
into the mass storage system.
The second activity, the production of DST was performed for PHENIX fourth- and ﬁfth-year p + p experimental data. In particular, for the ﬁfth-year experimental data, simultaneous production with data transfer, that is, simultaneous with experiment, was carriedout as a trial. The status of the production was monitored 24 hours by worldwide PHENIX collaboratorswith HTTP.
During the summer of 2005, an analysis workshop
was held at RIKEN for the spin analysis of ﬁfthyear experimental data. To put all the nDST in themedium-scale storage system, two RAID systems wereadditionally installed in June 2005. The total capacityof these two RAIDs is 13.6 TBytes. Two SUN Fire V40
machines were also installed as corresponding servers.
As Solaris10 for x86 does not support “pftp,” the interface of HPSS, servers are operated by Scientiﬁc Linux
4.0.
Other analytical activities can be found on the
web page: http://ccjsun.riken.go.jp/ccj/proposals/.
Achievements of those activities are reported on thisvolume.
As for maintenance, CCJ encountered several troubles. The ﬁrst trouble was the memory leak and system crash of the NIS/user home server. The server
was operated by Solaris2.6 whose support service by
the vendor is now discontinued. Presently, those services are moved to another machine that is operated bySolaris8. The OS upgrading of the phased out server isbeing planned. The Hard Disk Drive (HDD) of RAID
crashed several times and the broken disk was changed.
The ﬁle system crashed once due to a crash of another HDD during the rebuilding of RAID, however,the system could be restored without causing further
problems. There were two troubles with the FC interface: one was a damaged ﬁber cable and the other was
the broken FC HUB. These damaged cable and broken
HUB were already changed. Eighteen nodes of the calculation node crashed due to hardware problems. Oneof the nodes was ﬁxed by changing HDD. In total in
the past year,6) 35% of the calculation nodes crashed.
These nodes were installed in 1999–2001 and the performance of these nodes are much lower than newer
nodes. The eﬀect of the phaseout is quite negligible
with respect to the total performance of CCJ. The incidence of system crashes of calculation nodes and thesubsystem of HPSS increased slightly with the increasein loads on the system due to DST production and theanalysis workshop.
Figure 1 shows the total capacity and the used spaceof RAIDs for each RHIC year. The volume of ﬁfthyear nDST data reached 26 TBytes but only 18 TByte
data is in RAIDs due to the limited remaining space.
The subsequent analysis of third- and fourth-year datais consuming a space of 4 TBytes. The usage of volume by each analysis activity is growing more than
10 TBytes and the disk volume is nearly close to thelimit. The shortage of capacity is a serious problem forthe planned reproduction of DST for ﬁfth-year data
and for future analysis. A further upgrading of themedium-scale storage system is highly expected and isbeing discussed.
The usage of HPSS volume is shown in Fig. 2. The
current limit of HPSS volume is 0.8 TByte and an ex-

Fig. 1. Volume space of RAIDs at each RHIC experimental year. Circles indicate total volume, squares thespace consumed by all the nDST stored and triangle
total used volume. “Total volume” does not include
the buﬀer region of RIKEN-BNL transfer system. The
system is close to its limit.

Fig. 2. Volume usage of HPSS for each RHIC experimental
year. The HPSS system is also close to its limit of
1 PByte.

tension is possible only up to 1 PByte. The plan for
HPSS upgrade is being considered carefully: adding
tapes into another silo and/or the introduction ofnewer robot/tape systems.
References
1) M. Harrison, T. Ludlam, and S. Ozaki: Nucl. Instrum.
Methods Phys. Res. A 499, 235 (2003).
2) D. P. Morrison et al.: Nucl. Phys. A 638, 565c (1998).
3) http://www.platform.com/products/LSF/4) http://www.hpss-collaboration.org/hpss/index.jsp
5) Y. Watanabe et al.: RIKEN Accel. Prog. Rep. 39, 222(2006).
6) S. Yokkaichi et al.: RIKEN Accel. Prog. Rep. 38, 247(2005).

225

RIKEN Accel. Prog. Rep. 39 (2006)

Pumping 229m Th by hollow-cathode discharge [III]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 Y. Suzuki,∗1 K. Takamiya,∗5 S. Watanabe,∗1 A. Yokoyama,∗3 and H. Yuki∗4
We proposed a new method of populating the “3.5eV isomer” in 229 Th by hollow-cathode electric discharge.1,2) This exotic isomer has long been sought but
as yet not conﬁrmed. Last year, we found no long-lived
isomer but only a sign of α decay with a half-life shorter
than 20 minutes.3) Measurement was carried out asfollows. The hollow cathode with a sample of 229 Th
subjected to electric discharge was removed from thetube after switching oﬀ the discharge, and the sample
was dissolved to make an α source. About 20 minutes
after the discharge, α spectra were measured successively for 10 minutes. If the sign of a short-lived isomeris conﬁrmed, then it will be an epoch-making discovery
in this ﬁeld of spectroscopy, since the isomer was ﬁrst
postulated in 1976.4) To examine an α decay shorter
than 20 minutes, we have installed an α detector inside
the hollow-cathode discharge tube.
Figure 1 shows our new setup with an αmeasurement assembly: (1) a Si detector (ORTEC Btype with 150-mm2 active area and 300-µm depleted
depth), (2) a light-shield housing made of Al, and (3) athin light-tight-ﬁlm (4-µm Mylar coated with Al 80 nm
thick) window. As was described in our last reports,2,3)
we use Ar gas at a pressure of 200 Pa in the discharge
tube, a discharge current of 100 mA or 200 mA and a
voltage of about 300 V (constant current mode). We
achieved light shielding suﬃcient for detecting α particles during the discharge. The energy resolution with
the Al-coated Mylar window is about 80 keV full widthat half maximum (fwhm) for 241 Am 5486-keV alphas.
(For the same alphas, the detector has an energy resolution of 17 keV fwhm in vacuum at room temperature;
about 40 keV fwhm at an Ar-gas pressure of 200 Pa
without the Al-coated Mylar window.) This resolution
with the Mylar window is not suﬃcient for identifying
individual α lines but it is suﬃcient for recording α
spectra.
Now we can measure α particles during the electric
discharge and the change in their yields with time immediately after switching oﬀ the discharge. A preliminary measurement using the present setup suggeststhat there is a delayed α component with a half-life
shorter than 16 minutes. Full measurement will be
carried out shortly at the Oarai branch of the Institute for Materials Research, Tohoku University.
∗1
∗2
∗3
∗4
∗5

Fig. 1. Schematic cross-sectional view of our hollowcathode discharge tube with α-measurement assembly:(1) SSD, (2) light-shield housing, and (3) thin lighttight-film window.

References
1) H. Haba et al.: RIKEN Accel. Prog. Rep. 37, 263(2004).
2) T. T. Inamura, T. Mitsugashira, and the Oarai collaboration: Hyperfine Interact., in press.
3) S. Enomoto et al.: RIKEN Accel. Prog. Rep. 38, 249(2005).
4) L. A. Kroger and C. W. Reich: Nucl. Phys. A 259, 29(1976).

Oarai Branch, Institute for Materials Research, Tohoku University
Graduate School of Science, Osaka University
Graduate School of Natural Science and Technology,
Kanazawa University
Laboratory of Nuclear Science, Tohoku University
Research Reactor Institute, Kyoto University

227

RIKEN Accel. Prog. Rep. 39 (2006)

Status report on RIKEN ECR ion source operation
Y. Higurashi, T. Nakagawa, M. Kidera, H. Haba, T. Aihara, M. Kase, A. Goto, and Y. Yano
In 2005, we successfully produced two special ion
beams (70 Zn, 238 U) from RIKEN 18 GHz ECRIS andan intense Ar beam from the liquid-He-free superconducting ECR ions source for nuclear physics experiments. One of the requirements of the RIKEN RI
beam factory (RIBF) project is the production of U ion
beams.1) We therefore study how to produce a beamof U ions. As the ﬁrst trial, we used UF6 for the production of the U ion beam from an ECR ion source.
When using UF6 , it does not require an oven nor an insertion system for the solid rods to be vaporized underplasma sputtering. It is possible to produce U ions inthe same manner as in the case of producing gaseous
elements. Figure 1 shows a cross-sectional view of the
RIKEN 18 GHz ECRIS and a schematic drawing of theUF6 bottle. Details of the description of the RIKEN
18 GHz ECRIS and its performance are described inRef. 2. The UF6 bottle (50 cm3 in volume) was connected by a gas-feeding tube via a variable slow-leakvalve to control the ﬂow rate of UF6 vapor. About
3 g of UF6 was ﬁlled in to the UF6 bottle. No gasmixing method was applied during the present experiments. To minimize contamination, the plasma chamber wall was covered up with a thin aluminum tube of
1 mm thickness, which is easily replaceable. Furthermore, the aluminum surface emits several secondary
electrons per primary electron impact, which helps increase plasma density.3)
Figure 2 shows the charge state distribution of Uions. The ion source was tuned for the production of
U21+ ions. The injected microwave power was 260 W.
The gas pressures of the plasma chamber and extraction stages were 9.0 × 10−7 and 1.0 × 10−7 Torr, respectively. The extraction voltage was 10 kV. Figure 3

Fig. 1. Cross-sectional view of RIKEN 18 GHz ECRIS andschematic drawing of UF6 bottle.

Fig. 2. Charge state distribution of U ions. The ion source
was tuned for the production of the U21+ ions.

Fig. 3. Beam intensity of multicharged U ions at extraction
voltage of 12 kV.

shows the summary of the beam intensity of multicharged U ions at the extraction voltage of 12 kV.
Recently, an intense 70 Zn beam has been strongly
demanded for use in the search for a new superheavy
element (atomic number of 113).4) . The goal of superheavy element search experiments was to generate
an intense beam of Zn14+,16+ ions (at least 2–3 pµA)
from the ion source for as long as possible withouta break minimize the experimental time, because theestimated cross section of the reaction is very small[smaller than pb (10−36 cm2 )]. To produce 70 Zn ions,
we used the direct insertion method. At ﬁrst, we measured the beam intensity of Zn ions from a natural
ZnO rod. The size of the rod was 4 × 4 × 40 mm3 .
To check the eﬀect of ionized gas (base gas for the
production of plasma) on beam stability and intensity,
we chose He and O2 gases as ionized gases. Usually,229

for the production of Zn ions, O2 gas is better thanHe gas, because the ion cooling eﬀect of O ions on Zn
ions is much better than that of He ions.5) However,in this experiment, the beam intensity of Zn ions produced using He gas is more stable than that produced
using O2 gas. For this reason, we used He gas as an
ionized gas. Usually, we have to set the rod near the
ECR zone to obtain suﬃcient vapor pressure from ahigh-melting-point material, such as ZnO. (The melting point of ZnO is 1975◦ C.) However, remarkably, theposition of rod tip (L) was 3 cm, which was 10 cm fromthe ECR zone, to obtain a 50 eµA 64 Zn15+ ion beam.
To understand this phenomenon, we need too carryout further investigations. Practically, it was advantageous to obtain a stable beam, because the solid rod
does not cause the instability of the plasma.
Based on these experimental results, we attempted
to produce the 70 Z ion beam with a 70 ZnO rod. Figure 4 shows the charge state distribution of 70 Zn
ions. The RF power was 560 W, the gas pressure was
7.4×10−7 Torr, and the extraction voltage was 15.6 kV.
Using this method, we successfully produced an intense
beam of 70 Zn16+ (∼ 2 pµA) for 43 days without breakfor superheavy element search experiments.
To accelerate the intense Ar beam (∼ 1 pµA) up
to 63 MeV/u using the heavy-ion linac-ring cyclotron
accelerator complex, we produced the Ar9+ ion beamfrom the superconductiong ECR (SC-ECR) ion source(RAMSES).3)
The typical beam intensity of Ar9+ from an ion
source is approximately 13 pµA. Figure 5 shows the
charge state distribution of Ar ions. The ion source wastuned for the production of Ar9+ ions. The injected
microwave power was 210 W. The gas pressures of theplasma chamber and extraction stages were 3.0 × 10−7
and 2.7 × 10−7 Torr, respectively. The extraction voltage was 15.8 kV. Using this ion source, we obtained ahigh transmission eﬃciency of 95% from the ion source
to the RFQ linac and successfully supplied ∼ 1 pµA of
Ar beam on the target for nuclear physics experiments.

Fig. 5. Charge state distribution of Ar ions. The ion source
was tuned for the production of Ar9+ ions.

References

Fig. 4. Charge state distribution of 70 Zn ions from RIKEN
18 GHz ECR ion source produced by direct insertion.
The ion source was tuned to produce 70 Zn16+ .

230

1) Y. Yano: Proc. 17th Int. Conf. on Cyclotrons and Their
Applications, Tokyo, 2004-10 (Japan Particle Accelerator Physics Society, 2005), p. 169.
2) T. Nakagawa, Y. Higurashi, M. Kidera, T. Aihara, M.
Kase, and Y. Yano: Nucl. Instrum. Methods Phys. Res.
B 226, 392 (2004).
3) T. Nakagawa, T. Kurita, M. Kidera, M. Imanaka, Y.
Higurashi, M. Tsukada, S. M. Lee, M. Kase, and Y.
Yano: Rev. Sci. Instrum. 73, 513, (2002).
4) 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. S. Xu, T. Yamaguchi, A. Yoneda, A.Yoshida, and Y.
L. Zhao: J. Phys. Soc. Jpn. 73, 2593 (2004).
5) A. Drentje, A. Girard, D. Hitz, and G. Melin: Rev. Sci.
Instrum. 71, 623 (2000).

RIKEN Accel. Prog. Rep. 39 (2006)

Production of high intensity 7 Li3+ ion beam
Y. Ohshiro,∗ S. Watanabe,∗ S. Yamaka,∗ Y. Higurashi, and S. Kubono∗
At the AVF cyclotron facility in RIKEN, high intensity 7 Li3+ ion beams were successfully produced bya Hyper ECR ion source1) using a micro-oven method
for nuclear astrophysics experiments at the CRIB separator2) this year. To production of intense 7 Li3+ ions,a crucible insertion method has been developed to feed
the vapor of metallic elements into the discharge chamber. The method is applicable to production of highcurrent stable ion beams from low melting-point material like Li. Thereby, the maximum beam current of
75 eµA was produced by the Hyper ECR ion source.
This current was roughly equivalent to the value obtained at Dubna.3)
According to CRIB scientiﬁc programs, one of the
key ions required is the high intensity 7 Li2+ and 7 Li3+
beams. The 7 Li2+ ions were preliminary produced
by a rod insertion method4) using LiF solid material,and used for the experiment at CRIB. The maximum
beam intensity of 7 Li2+ extracted from the source was
48 eµA, a 7 Li3+ beam intensity of about 3.5 eµA (SeeTable 1). However, in this case, the beam intensity
decreased drastically by a bad vacuum pressure, because the LiF rod (melting point being 870◦ C) evaporated quickly by the higher RF power required thanfor 7 Li2+ ion production.
In order to produce a high intensity 7 Li3+ beam,a crucible insertion method has been developed. A
schematic drawing of the crucible insertion system inthe Hyper-ECR ion source is shown in Fig. 1. The system consists of a container (called a crucible) of stainless steel with a heat-resistant attachment of Ta (calleda cap) and a thin cylindrical Ta sheet (called a hot
liner) placed inside the discharge chamber to preventthe condensation of metal at the chamber wall. The
crucible that contained metallic Li was placed near the
ECR zone to vaporize and supply the material into the
ECR zone. Moreover, a hot liner was set on the discharge chamber wall with a 0.5 mm gap. The hot liner
inside the discharge chamber provides a better condition to produce intense beams for elements of solids
with relatively low melting point.
Since the ions of 7 Li3+ and 14 N6+ cannot be separated by the mass analyzer of the ECR ion source,

Fig. 1. Schematic drawing of crucible insertion system inHyper-ECR ion source.

the beam intensities of 7 Li3+ were ﬁrst estimated bycomparing them with the quantity of the 14 N5+ ions(indicated by the dotted line in Fig. 2). Then, the intensity ratio of 7 Li3+ was measured by the cyclotron.
The 7 Li3+ ion beam was injected axially together withthe 14 N6+ beam into the cyclotron. But, the 14 N6+ions were well separated by the cyclotron. In the caseof 7 Li3+ injection, the transmission eﬃciency from the
ECR source to the exit of the cyclotron was about 4–
6%.
The operating conditions of the ECR ion source for
7 3+
Li production were as follows. The two peaks of themirror ﬁelds were 10.5 kG and 11.5 kG, and the lengthof the ECR zone was approximately 70 mm. The RF(14.2 GHz) power was approximately 320 W, and helium gas was fed into the discharge chamber as a supporting gas. The vacuum pressure was 7 × 10−7 Torrin operation.
A nice feature of this crucible insertion system isthat the beam intensity can be change by moving theTable 1. 7 Li beam intensities produced.

∗

Center for Nuclear Study, Graduate School of Science, University of Tokyo

Fig. 2. The beam intensity obtained as a function of distance to the crucible from the center of the sextupole
magnet.

231

crucible position. The beam intensity increases when
moved closer to the ECR zone. Figure 2 shows thebeam intensity obtained as a function of distance tothe tip of the crucible from the center of the sextupole
magnet. As an example, the 7 Li3+ beam intensity was
75 eµA at the distance of 115 mm, and 7 Li2+ ions was
200 eµA at the same distance.
The Li consumption was approximately 15 mg/h inlong-term operation (up to 6 days) with the 7 Li3+ injected current of 20–40 eµA. The crucible has a lengthof 52 mm and the useful volume is about 9 cm3 . Thus,
this method will be able to provide the beam for about
300–350 hours.

232

A further development on the stability and the intensity is in program for long-term operation.
References
1) Y. Ohshiro et al.: RIKEN Accel. Prog. Rep. 36, 279(2003).
2) Y. Yanagisawa et al.: Nucl. Instrum. Methods Phys.
Res. A 539, 74 (2005).
3) S. L. Bogomolov et al.: Proc. 13th Int. Workshop on
ECR Ion Sources, Cern, Geneva, Switzerland, 1999-5(CERN, 1999), p. 71.
4) Y. Ohshiro et al.: RIKEN Accel. Prog. Rep. 38, 253(2005).

RIKEN Accel. Prog. Rep. 39 (2006)

Conceptual design of a 28 GHz superconducting ECR ion source
T. Nakagawa, M. Kidera, Y. Higurashi, J. Ohnishi, H. Saitoh, A. Goto, and Y. Yano
To achieve 1 pµA of U ion beam at 350 MeV/u,higher than 15 pµA of U35+ ion beam is required froman ion source, unless we use the ﬁrst charge stripper.
To produce such intense beam of highly charged heavyions, we have to use a higher magnetic mirror ratio anda higher microwave frequency (> 18 GHz) to increase
plasma density and ion conﬁnement time.
Figure 1 shows the schematic drawing and magnetic
ﬁeld strength of the superconducting ECR ion source
which has an operational frequency of 28 GHz. To obtain a larger plasma volume, we use a special geometrical arrangement of the solenoid coils (Flat Bmin conﬁguration) as shown in Fig. 1. Using this arrangement,
we obtain the volume 3–4 times larger than that forclassical magnetic ﬁeld conﬁguration. A sextupole ﬁeld
is generated by six racetrack coils wounded arounda pole piece. To obtain a good plasma conﬁnement

Fig. 1. Schematic drawing of SC-ECRIS and magnetic field
configuration.

at 28 GHz, we need a maximum mirror magnetic ﬁeld
strength of 4 T and a radial ﬁeld strength of 2 T.
Calculations using the three dimensional codes
TOSCA were used to develop the superconducting
magnet structure. The inner and outer diameters ofsolenoid coil 1 were 290 and 450 mm, respectively. The
estimated total stored energy was 300 kJ under thiscondition.
We found that the magnetic ﬁeld gradient at theresonance zone plays an essential role in increasing theplasma density and electron temperature. Magnetic
ﬁeld gradient strongly depends on the minimum magnetic ﬁeld strength (Bmin ) of the mirror ﬁeld.1,2) Using
this coil arrangement as shown in Fig. 1, we can change
Bmin without changing maximum magnetic ﬁeld (Bext
and Binj ) independently to optimize the magnetic ﬁeld
gradient at the resonance zone.
The inner diameter and length of the plasma chamber are 15 and 50 cm, respectively. The plasma chamber wall is made of Al to donate cold electrons to theplasma to decrease plasma potential.3,4) Note that Al
is very resistant to plasma etching. This reduces contamination in the plasma of the ions from the wall. A
biased electrode is installed to obtain the same eﬀect
as that of the Al chamber wall.5) The cooling of all
surfaces in contact with the plasma using water minimizes the temperature eﬀects caused by plasma andmicrowave heating at high microwave power.
At lower microwave frequency (< 18 GHz), one of
the high performance ECR ion sources is the AECRU at the LBL, which has an operational frequency of
14 GHz.6) The beam intensity of U35+ ions is about
16 eµA at an RF power of 1 kW as shown in Fig. 2.
The volume of the resonance zone of the new RIKEN
SC-ECR ion source described here is 10-fold larger

Fig. 2. Beam intensity of U ions from AECR-U.

233

than that of the AECR-U. The microwave frequency is
two-fold higher than that of the AECR-U. This meansthat in principle the new ion source can produce anintensity 40-fold higher than that of the AECR-U.
However, we have to use a higher microwave power(∼10 kW) to obtain suﬃciently high electric ﬁeld gradient at the resonance zone, because the plasma chamber volume is quite large (about 8 L), which is ∼10–foldlarge volume of the AECR-U.
The expected total current from the ion source ishigher than 10 mA. In this case, the normalized emittance of highly charged heavy ions is estimated to be
1 πmm · mrad, which is mainly caused by the spacecharge eﬀect. Under this condition, we have to supply a very high extraction voltage (higher than 60 kV)
to obtain a good emittance (unnormarized emittanceof ∼150 pmm · mrad) for matching the acceptance of
the RFQ linac. The ion source will be equipped witha movable accel-decel extraction system not only to234

improve the extraction conditions, but also to compensate for the space charge eﬀect.
References
1) H. Arai, M. Imanaka, S. M. Lee, Y. Higurashi, T.
Nakagawa, M. Kidera, T. Kageyama, M. Kase, Y. Yano,
and T. Aihara: Nucl. Instrum. Methods Phys. Res. A
491, 9 (2002).
2) M. Imanaka, T. Nakagawa, H. Arai, I. Arai, and S. M.
Lee: Nucl. Instrum. Methods Phys. Res. B 237, 647(2005).
3) T. Nakagawa: Jpn. J. Appl. Phys. 30, L930 (1991).
4) T. Nakagawa, Y. Miyazawa, M. Hemmi, T. Chiba, N.
Inabe, M. Kase, T. Kageyama, O. Kamigaito, A. Goto,
and Y. Yano: Jpn. J. Appl. Phys. 35, 4077 (1996).
5) S. Biri, T. Nakagawa, M. Kidera, Y. Miyazawa, M.
Hemmi, T. Chiba, N. Inabe, M. Kase,T. Kageyama,
O. Kamigaito, A. Goto, and Y. Yano: Nucl. Instrum.
Methods Phy. Res. B 152, 386 (1999).
6) Z. Q. Xie: Rev. Sci. Instrum. 69, 625 (1998).

RIKEN Accel. Prog. Rep. 39 (2006)

Improvement for stable operation of flattop acceleration system of
AVF cyclotron
S. Kohara, O. Kamigaito, N. Sakamoto, M. Kase, T. Chiba, K. Masuda,∗1
Y. Chiba, S. Watanabe,∗2 K. Kumagai, and A. Goto
The ﬂattop acceleration system in the AVF cyclotron has been developed to improve the transmission eﬃciency and energy spread of beams. The additional resonator was installed in August 2001. The
ﬂattop accelerating voltage was generated by the superposition of the fundamental and third harmonics
on the dee and a beam of good quality was successfully obtained in a beam acceleration test.1) However,
we encountered a serious problem on atmospheric discharge at the lower ceramics insulator support for themain coaxial resonator, which is shown in Fig. 1, whenthe maximum ﬂattop accelerating voltage was generated. The discharge does not occur when the dee is
excited with a fundamental voltage only even at the
maximum. The reason for this diﬀerence is that thepeak voltages of the fundamental and third harmonics
are cumulatively superposed at the ceramics insulator
support, because the phase of the third harmonics isinverted between the dee and the ceramics insulator
support while that of the fundamental is unchanged.

Fig. 2. Photograph of inside of main amplifier, in which
teflon covers are attached to lower ceramics insulator
support.

Fig. 1. Cross-sectional view of main resonator equipped with additional resonator for flattop acceleration
system and power amplifiers. Teflon covers are attached to the upper and lower sides of the lower
ceramics insulator support.
∗1∗2

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

235

Moreover, the discharge occurs mainly at the lower
ceramics, not at the upper ceramics, due to the geometrical asymmetry of the system.
To clarify this discharge problem, teﬂon covers were
manufactured and attached to the upper and lower
sides of the lower ceramics insulator. They were used
to suppress the emission of electrons at a high potential. A photograph of the inside of the main ampliﬁer,
in which the teﬂon covers are attached to the lower
ceramics insulator support, is shown in Fig. 2. Af-236

ter attaching the teﬂon covers, the atmospheric discharge hardly occurred in the power test of the ﬂattop
acceleration system. The voltages of the fundamental and third harmonics can be stably generated at
45 kV and 5 kV, respectively, when the fundamental
frequency was 16.3 MHz.
Reference
1) S. Kohara et al.: Nucl. Instrum. Methods Phys. Res. A
526, 230 (2004).

RIKEN Accel. Prog. Rep. 39 (2006)

Study of new flat-top resonator for RRC
L. Stingelin, A. Goto, O. Kamigaito, N. Sakamoto, and Y. Yano
Flat-top resonators are commonly used in cyclotrons
to add a third1,2) or ﬁfth3) harmonic to the accelerating voltage. The resulting broader acceleration voltage reduces the energy spread of particle bunches andhence the extraction losses of the cyclotron, which isusually the limiting factor for beam intensity. Since
the beam losses in the RIKEN Ring Cyclotron (RRC)
might limit the beam intensity of the RIKEN Accelerator Research Facility, a design study for a ﬂat-top
resonator was launched.
The ﬂat-top will be achieved by a third-harmonicresonator with a frequency range of 54–120 MHz and a
total peak gap voltage of approximately 135 kV. This
new resonator could replace the “valley box SE,” where
currently only phase probes and four vacuum pumps
are located. Its boundaries are limited by the positionsof the ﬁrst and last turns, the injection and extraction
bending magnets and the sector magnets “east” and“south” as indicated in Fig. 1. Therefore, the available
space is small and it is challenging to ﬁnd a resonatorshape that ﬁts into the cyclotron.
In the ﬁrst step, three diﬀerent types of resonator geometry were investigated. The three-dimensional electromagnetic eigenmode solver in ANSYS4) was used
to simulate and compare a single-gap resonator withtwo double-gap resonators, one operated in the fundamental mode with a phase shift of 180◦ between thegaps and the other operated in a higher mode with adoubled opening angle and a phase shift of 0◦ . For
all three types of resonator geometry, a geometry was
found that ﬁts into the valley box. However, the double gap resonator in the fundamental mode showed themost promising characteristics. It can be inserted into
one half of the valley box, leaving the other half of thevalley box free for the phase probes and the vacuum

Fig. 1. Top view of proposed valley box with ﬂat-top resonator: phase probes (PP), capacitive coupler (CC),ﬁne tuner (FT), injection, extraction bending magnets(BM1, EBM1) and sector magnets (SM).

pumps. Furthermore, it requires less rf power thanthe other resonators and requires no intensive coolingon the sidewalls close to the injection and extraction
magnets. However, the double-gap design has the disadvantage of a reduced eﬃciency for some harmonic
numbers, since the Dee angle is ﬁxed and therefore cannot have the optimal value for all the harmonic modesof the cyclotron. Furthermore, the use of one half ofthe valley-box leads to small particle momentum kicks
in the radial direction, since one gap is necessarily not
perfectly perpendicular to the trajectory of the particles.
In the second step, a reﬁned simulation model ofthe double-gap resonator was created, enabling the direct three-dimensional analysis of the surface ﬁelds andthe rf parameters. The full parametrization of thesimulation geometry was very convenient for the efﬁcient optimization of the resonator geometry. Dueto mirror symmetry of the geometry with respect tothe beam plane, only one half of the structure had
to be simulated. This type of simulation used approximately 180,000 elements, 270,000 nodes and thesolver required approximately 700 MBytes of memory when second-order tetrahedral elements (ANSYStype “HF119”) were used. The calculation times wereapproximately ﬁve minutes for preprocessing, including the generation of geometry and meshing, approximately one hour for solving and approximately ten
minutes for post processing.
It was found that, at higher frequencies, a design
with two stems (see Fig. 2) is superior to a design
with one stem only. Preliminary simulation results pre-Fig. 2. Flat-top resonator with removed sidewall. The
shorting plates are set to an operation frequency of
68 MHz. The rf-geometry has an approximately 2.64 m
maximum length, 0.68 m maximum width and 2 m maximum height.

237

dicted a maximum quality factor of Q0 = 13, 900 at an
operation frequency of 85 MHz and a minimum quality factor of Q0 = 12, 000 at 120 MHz. Figure 3 showsthat coarse tuning of the resonator can be achieved bychanging the vertical position of the shorting plates.
A resonance frequency of 52.6 MHz is reached at a
distance of 1.0 m from the beam plane and 120 MHz
is reached at a distance of 23.5 cm for example. The
bellows for the adjustment of the resonance frequency
must therefore reach approximately 77 cm beyond theupper and lower cavity wall.
For the calculation of the gap voltage distribution in
Fig. 4 and the power requirement in Fig. 5, the ﬁelds
were then scaled according to the following procedure.
The mean gap voltage is adjusted to be equal to thesum of the mean gap voltage of the main resonators,
divided by nine. The calculations are performed fora peak voltage of 300 kV in the gaps of the main resonators. Actual ﬁeld values and power requirements at

Fig. 3. Coarse tuning of resonator operation frequency.
The distance of the shorting plate to the beam plane
is indicated.

Fig. 5. Power requirement in function of operation frequencies. Power losses in rf contacts are not taken into account.

frequencies lower than 90 MHz will be smaller becauseof limitations in the main resonators at corresponding
frequencies.
Since the ﬂat-top voltages are decelerating, a radially decreasing gap voltage in Fig. 4 leads to a compression of the particle bunches by the rf magnetic ﬁeld andincreasing gap voltage to decompression.5) The resulting eﬀect on the particle distribution will be analyzed
by detailed beam dynamic simulations.
The highest current density in the shorting plateof 23 A/cm was found at an operation frequency of
113 MHz and the maximum electric ﬁeld in the resonator of 3.7 MV/m at a frequency of 90 MHz. Thisﬁeld strength is lower than half of Kilpatrick’s electricﬁeld limit.6)
In the future, we will investigate the mechanical andthermal design of the resonator and ﬁnalize the coupling7) and ﬁne-tuning method. In addition, the rf
parameters will be optimized further.
This work is supported by the Japanese Society for
the Promotion of Science as postdoctoral fellowship.
Support of the RIKEN Computing Center is also gratefully acknowledged for providing the necessary simulation resources.
References

Fig. 4. Gap voltages for gap 1 in function of radius. Voltage distributions are shown for four diﬀerent operation
frequencies. Gap 2 has approximately the same gap
voltage distribution.

238

1) W. Joho: Proc. 11th Int. Conf. on Cyclotron and Their
Applications, Tokyo, 1986-10 (Ionics Publishing Company, 1987), p. 31.
2) S. Kohara et al.: Nucl. Instrum. Methods Phys. Res.
A 526, 230 (2004).
3) J. L. Conradie: Proc. 14th Int. Conf. on Cyclotron and
Their Applications, Cape Town, South Africa, 1995-11(World Scientiﬁc, Singapore, 1996), p. 249.
4) http://www.ANSYS.com
5) T. Fujisawa: Nucl. Instrum. Methods Phys. Res. A 292,
1 (1990).
6) W. D. Kilpatrick: Rev. Sci. Instrum. 28, 824 (1957).
7) P. Balleyguier: Part. Accel. 34, 113 (1997).

RIKEN Accel. Prog. Rep. 39 (2006)

Status of control and beam interlock system for RARF and RIBF
M. Kobayashi-Komiyama, M. Fujimaki, I. Yokoyama, and M. Kase
We report two major achievements for the control
system of RARF and RIBF this year; one is the replacement and expansion of the EPICS control network system, and the other is the introduction of the
new beam interlock system to RARF.
We have started to control the magnet power supplies of SRC and some of the pieces of beam diagnostic
equipment of IRC using EPICS this year. Following
this expansion of the control system and considering
the total number of devices that will be controlled by
EPICS in one or two years, we faced a problem in our
EPICS control network system. Because it was constructed as a ﬂat one, we could assign a smaller numberof control devices to the network than our needs. We
can assign up to 128 control devices in the previous
system. Considering only the N-DIM system, which
is used as a controller of beam diagnostic equipment
and a vacuum system among others, more than 100
IP addresses are required in RARF and RIBF because
each N-DIM uses one IP address. Because we use not
only N-DIMs but also other controllers such as PLC,
server computers and PCs for the operator interface inthe network, we have to expand the control network
system. Therefore, we discussed with Fujitsu Corporation about the best solution for the expansion of our
network system.
The new network system is shown in Fig. 1. It was
designed to have ﬁve subnetworks in the system. The
ﬁrst subnetwork is used for the VME, its server computer, PCs for an operator interface and high-level control computers that work for data archiving and alarmsystems among others. The second subnetwork is used
for N-DIM for the Faraday cup control and vacuum
control and their server computer. The third subnetwork is used for the N-DIM for a beam proﬁle monitor and radial probe and their server computer. The
fourth subnetwork is used for PLC and its server computer, and the last subnetwork is used for the maintenance of the network system itself. We newly introduced one Cisco’s Catalyst 4506 device as a routerand nine Catalyst 2950 devices as edge switches, andset up optical ﬁber cables among them. The routerwas placed at the control room of Nishina building,which is the main control room of RARF and RIBF.
Three edge switches were placed in Nishina building,and four in Linac building, and two in RIBF accelerator building. We replaced our control network insummer. The performance of the network in terms ofcommunication speed and stability is equal to that ofthe previous network. It has worked well without any
troubles.
In RARF, we have been using a beam interlock system that is based on CAMAC-CIM/DIM for approximately 20 years. We have to expand it to include fRC
and its beam transport line in one year. However, it
is not a good idea to expand an old system such as
CAMAC. Therefore, we introduced a new beam interlock system using PLC to RARF in addition to thecurrent system. The new system will include signals
from RRC, fRC and their beam transport line placed
from the joint building to E1. The development of a
prototype of the system started in 2001, and the prototype has been working as a beam interlock system
in RILAC for approximately three years. When we
designed the RRC-fRC beam interlock system on thebasis of the prototype, we expanded its function. The
structure of the system is shown in Fig. 2, and detailsof the system are described in another paper.1) The
main features of the system are as follows:• The system is constructed using ﬁve Melsec PLCs

Fig. 1. Structure of RARF and RIBF control network system.

Fig. 2. Structure of beam interlock system for RRC/fRC.

239

and connected to each other with optical ﬁber cables.
• The beam is stopped by the beam chopper at theexit of the ion source of RILAC within 5 seconds
after the system receives a digital or analog interlock signal.
• We can set an interlock signal pattern dependingon the type of beam or operation mode at one timeby downloading a ﬁle from PC to PLC as well as
by setting each signal manually (new function).
Each PLC station is set at the following place: threestations are placed at the corridor of a controlled areain Nishina building, one station is set at the control
room in Nishina building and the last one is set at the240

joint building. As a ﬁrst step in using this system, we
replaced the control system for reading beam current
from the baﬄe slits of the entrance and exit areas of
the RRC from the CAMAC-CIM/DIM to N-DIM, andthose 27 signals were connected to three stations of thebeam interlock system. We conﬁrmed that it works
well during a beam service time in October. We aregoing to include more input signals such as those fromthe vacuum system or magnet power supplies graduallynext year.
Reference
1) M. Kobayashi-Komiyama et al.: Proc. 2nd Annu. Meet.
of Particle Accelerator Society of Japan and 30th Linear
Accelerator Meet. in Japan, Tosu, 2005-7 (2005), p. 615.

RIKEN Accel. Prog. Rep. 39 (2006)

Longitudinal profile monitor using plastic scintillator for RARF
T. Watanabe, M. Kase, M. Wakasugi, N. Fukunishi, and Y. Yano
New plastic scintillation proﬁle monitors have been
fabricated to evaluate energy and a longitudinal proﬁle of heavy-ion beams for the RIKEN Accelerator Research Facility (RARF). Two sets of longitudinal proﬁle monitors were installed into the transport line of
the RIKEN heavy-ion linac (RILAC) and the RIKEN
ring cyclotron (RRC). Preliminary experimental results obtained using the heavy-ion beam are describedin this article.
When a scintillation material is struck by a charged
particle, some ﬂuorescence photons are created by theelectron energy loss due to the collision of the beam
particle with the target. These photons can be ampliﬁed by a photomultiplier that has extremely high sensitivity, and converted to a logical pulse by a discriminator. Finally, the longitudinal beam proﬁle can beobtained by using a time-to-digital converter (TDC),
which digitizes the time lag between start (detector
pulse) and stop (bunch clock) and stores the events
into the memory of the TDC. Furthermore, the energyof the beam can be measured on the basis of the timeof ﬂight (TOF) of the beam using a longitudinal proﬁle monitor set. The plastic scintillators are chosen forour monitors because they are cheap and easy to produce in nearly every mechanical shape. In the present
work, the plastic scintillating material is the NE-102
with a size of 30 × 30 mm2 , a thickness of 0.5 mm and a
decay constant of 2.4 ns. The speciﬁcations of the photomultiplier are tabulated in Table 1 and a photo anda schematic drawing of the longitudinal proﬁle monitor
are shown in Figs. 1 and 2, respectively. The plastic
scintillation is pneumatically driven by the pneumatic
rotary feeder.
Prior to the energy measurements by the TOF
method, preliminary measurements of the longitudinal proﬁle of the heavy-ion beam were carried out. For
the experimental measurements, one plastic scintillation proﬁle monitor set that was installed in the beamtransport line of RILAC was used. Taking into account the conversion time of the TDC (Lecroy 2228A)
of approximately 100 µs, the individual particles can becounted using scintillators if the count rate is less than

Table 1. Speciﬁcations of photomultiplier.
Multiplier tube
Type
Tube Size
Photocathode Area Size
Wavelength (Peak)Gain Typ.
Anode Rise Time Typ.

Hamamatsu R7400U
Metal packagedDia.16 mm
Dia.8 mm
420 nm
7.0 × 105
0.78 nsFig. 1. Photo of longitudinal proﬁle monitor using plastic
scintillator.

Fig. 2. Schematic drawing of longitudinal proﬁle monitor
using plastic scintillator.

104 . The time diﬀerence data between the pulse signal
detected by the plastic scintillator and the bunch clock(RF signal) is stored and the time spectrum can be obtained as a result. The time spectra measured using an
40
Ar9+ (3.65 MeV/u) beam, which represent the longitudinal beam proﬁle, are shown in Fig. 3. These measurements show a beam bunching eﬀect in a rebuncher,which was operated at a frequency of 37.75 MHz (aperiod of 26.49 ns). By subtracting the backgroundand the data with less than 30% of the amplitude andﬁtting these data using Gaussian curves, it has beenfound that the FWHM of the longitudinal phase width
was compressed from 65.0◦ to 50.8◦ . To maintain theminimal background, the Ar beam was attenuated to
between 200 cps to 300 cps using slits in these measurements. Next, let us evaluate the time resolution ofthis system, taking into account the following factors:(1) The time resolution ∆Tt of the TDC has beenmeasured to be less than 100 ps, which was calibrated using a precise clock generator, and the241jitter (∆Tj ) of the photomultiplier was 50 ps.
(2) The time for the beam to pass through the plastic scintillator (Tp ) is 19 ps because the ratio (β)
of beam velocity (v) to light velocity (c) was
0.08832 (v = βc) and the thickness of the plastic
scintillator was 0.5 mm.
(3) Since the beam size (Rb ) is typically 30 mm, themaximum time diﬀerence (∆Tb = Rb /c) in thetime it takes for the photons to reach the photomuptiplier through the light guide is 100 ps.
(4) The ﬁtting error of the Gaussian curve (∆Tf ) is
40 ps.

Fig. 3. Measured time spectra of 40 Ar9+ (3.65 MeV/u)beam, which represent longitudinal beam proﬁles.
These measurements show a beam bunching eﬀect ina rebuncher. By subtracting the background and thedata with less than 30% of the amplitude and ﬁttingthese data using Gaussian curves, it has been foundthat the FWHM of the longitudinal phase width wascompressed from 65.0◦ to 50.8◦ .

242

The total time resolution of this system ∆Ttotal canthen be evaluated to be approximately 156 ps using
the following equation.
∆Ttotal = ∆Tt2 + ∆Tj2 + Tp2 + ∆Tb2 + ∆Tf2 .
In the next step of the experiment, the precise energy
measurements of the heavy ion will be carried out by
the TOF method.

RIKEN Accel. Prog. Rep. 39 (2006)

Beam current measurement using HTS-SQUID monitor for RRC
T. Watanabe, M. Kase, Y. Sasaki,∗1 S. Watanabe,∗2 T. Ikeda, T. Kawaguchi,∗3 and Y. Yano
This year, a prototype of a highly sensitive
beam current monitor with a high-temperature superconducting (HTS) SQUID and an HTS magnetic
shield,1–7) that is the HTS-SQUID monitor, has been
installed in the beam transport line of the RIKEN
Ring Cyclotron (RRC). Unlike other existing facilities, the HTS-SQUID monitor allows us to measure theDC of high-energy heavy-ion beams nondestructively
in such a way that the beams are diagnosed in realtime and the beam current extracted from the RRC
can be recorded without interrupting the beam user’s
experiments.
This system consists of two vacuum chambers completely separated from each other: one for a cryostat inwhich the HTS SQUID, an HTS magnetic shield andan HTS current sensor are cooled, and the other for abeam chamber in which a beam passes through. In thepresent work, all these HTS fabrications are cooled bya low-vibration pulse-tube refrigerator that has a refrigeration power of 11 W at a temperature of 77 K.
The operation temperature can be set in the rangeof 64 K to 90 K (the critical temperature of the HTSSQUID) using a heater, because the pulse-tube refrigerator is capable of cooling the system to temperatures
lower than liquid-nitrogen temperature. Furthermore,
it is possible to stabilize the temperature of the HTSSQUID with an accuracy of 5 mK using a PID feedback
controller, which has four thermometers and a heater.
The temperature of the cold head was measured as afunction of time. Consequently, the deviation in thetemperature over a period of 18 hours was controlled
within 3.4 mK (1σ).7) Both the HTS magnetic shield
and the HTS current sensor were fabricated by dip
coating8) a thin Bi2 -Sr2 -Ca2 -Cu3 -Ox (Bi-2223) layer
on 99.9% MgO ceramic substrates. The HTS-SQUID
system (Model BMS-G manufactured by Tristan Technologies) is composed of a low-noise HTS-SQUID gradiometer (Y-Ba2 -Cu3 O7−δ ).9)
In addition to current measurement, an importantfunction has been performed in which the beam position can be measured by dividing the thin-layer HTS
current sensor into two parts and by setting a SQUID
on each bridge.10) It is our expectation that the HTSSQUID monitor will be capable of measuring beam
current and beam position simultaneously in real time.
Prior to the beam measurements in the RRC hall,preliminary measurements were successfully carriedout as follows: (1) the ﬁrst beam test of the HTSSQUID monitor in the beam transport line for the elec∗1∗2∗3

Matsushita Electric Industrial
Center for Nuclear Study, Graduate School of Science, University of Tokyo
KT Science Ltd.

tron cyclotron resonance (ECR) ion source in the CNS
experimental hall and (2) the second beam measurement at the E1 experimental hall in RIKEN to measure the current of the high-energy heavy-ion beam.7)
This year, aiming at practical use for accelerator operations, the authors installed the HTS-SQUID monitor
system in the beam transport line (Fig. 1 (a)) in the
RRC hall (Fig. 1 (b)). However, the SQUID electric
circuit, which has the dynamic range of 100 dB (from
1 µA to 0.1 A) and the frequency range from DC to
25 kHz, did not function normally due to the following reasons: (1) an RF background is caused by thehigh-power RF cavities of the RRC, which can produce a total power of 0.6 MW; (2) a large stray magnetic ﬁeld is induced by the main magnetic ﬁeld of theRRC (max. 1.67 T); (3) there are a neutron radiation dose of 25.5 Sv and a gamma radiation dose of
3.0 Sv for a period of one year. The radiation dosesof neutrons and gamma rays were measured using an
ionization chamber and a 3 He proportional counter, respectively. The actual radiation doses where the HTSSQUID monitor is installed should be higher than theabove values, because both dosimeters are located 4 m
above the HTS-SQUID monitor. These data gave tentative criteria for the judgment of safety for radiation
damage. After overcoming these diﬃculties by reinforcing the RF shield and hiding the ﬂux-locked loop
(FLL) circuit with lead and concrete blocks, there were
no more problems with the beam current measurement. As a result, a 10 µA 40 Ar15+ beam intensity(63 MeV/u) was successfully measured with a 500 nA
resolution, shown in Fig. 2, where a 1 µA beam produced 6.5×10−3 Φ0 of magnetic ﬂux at the input coilof the HTS SQUID. Futhermore, a long recording of
the extracted Ar beam current from the RRC without
interrupting the beam user’s experiments for approximately 4 hours was achieved, as is shown in Fig. 3 (a).
In this recording, several dips in beam intensity due toFig. 1. The authors installed the HTS-SQUID monitor system in the beam transport line (a) and in the RRC hall
(b).

243

Fig. 2. A 20 µA 40 Ar15+ beam intensity (63 MeV/u) was
succesfully measured in real time with a 500 nA resolution, where a 1 µA beam produced 6.5×10−6 Φ0 ofmagnetic ﬂux at the input coil of the HTS SQUID.

ECR ion source discharge can be observed at irregular intervals of 10 seconds to 60 minutes. Figure 3 (b)shows a magniﬁed image of Fig. 3 (a), which indicatesthat dips in current caused by ECR ion source discharge recovered within 400 ms. The current signals
were analyzed by a fast Fourier transform (FFT) for afrequency domain, and the results are shown in Fig. 4.
The amplitudes of ripples modulated on the beam current increased with beam current. All recording andcontrol systems are connected to a PC-based data acquisition system. Through the Ethernet, these systems
are linked to a laptop in the main control room located
200 m from the RRC hall. The sampling time for dataacquisition is 500 µs and 100 data points are averaged
to one data to improve the signal-to-noise ratio.

In this study, the authors intended to determine thepossibility of measuring the DC of high-energy heavyion beams nondestructively and in real time. Despite
being performed in an environment with strong gamma
ray and neutron ﬂux radiations, RF background andlarge magnetic stray ﬁelds, measurements were successfully carried out. Although the intensity of a submicroampere beam can be measured, a limit of minimum current higher than two orders of magnitude is required for fainter beam measurement. The possibilityof fabricating the new HTS bridge circuit and introducing high-permeability cores into the SQUID throughtwo holes has been investigated.10) Figure 5 shows apicture of the new SQUID and the high-permeability
cores. A test using a simulated beam current shows a
50-fold improvement in gain because the coupling eﬃciency of the transfer of the magnetic ﬁeld produced by
the simulated beam current to the SQUID is improved.
The authors are grateful to R. L. Fagaly and M.
Faley for valuable insights into the HTS-SQUID system and also thank S. Ono, B. Mizuno, H. Kanada, S.
Kojima and N. Koshio for their fruitful collaboration.

Fig. 5. Picture of new SQUID with two holes and highpermeability cores.

References

Fig. 3. (a) Measurement of 63 MeV/u Ar beam extracted
from RRC, which could be recorded for approximately
4 hours without interrupting beam user’s experiments.
(b) Magniﬁed image of (a) showing dips in current
caused by ECR ion source discharge, which recovered
within 400 ms.

Fig. 4. Results analyzed by fast Fourier transform (FFT),
which were measured at 0 h (beam oﬀ) (a), 0.7 h (b)and 3.75 h (c) in Fig. 3 (a).

2441) 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) Y. Ishikawa et al.: Advances in Supercond. (Proc.
ISS’91) 4, 1076 (1992) .
9) M. I. Faley et al.: IEEE Trans. Appl. Supercond.
(ASC2000) 11, 1383 (2001).
10) T. Watanabe et al.: RIKEN Accel. Prog. Rep. 38, 273(2005).

RIKEN Accel. Prog. Rep. 39 (2006)

Automatic sample changer for biological samples
H. Ryuto∗ , T. Abe, N. Fukunishi, Y. Hayashi, M. Kase, and Y. Yano
An automatic sample changer was constructed incompliance with numerous requests to irradiate a large
number of biological samples. The automatic sample changer realizes undisturbed irradiation on morethan 500 sample containers ﬁlled with biological samples without interruption for renewals of samples byhand at the heavily shielded beam line. Before the installation of the automatic sample changer, the maximum number of sample containers that were automatically irradiated by the automatic irradiation system1)
was from 5 to 9 according to the size of the sample
containers, so from 56 to 100 times renewal of sample
containers would be required to irradiate 500 sample
containers. Therefore, the automatic sample changer
allows eﬀective use of limited beam time.
Figure 1 shows a schematic view of the automatic
sample changer installed as a part of the automatic
irradiation system. The movable table for samples of
the automatic irradiation system was replaced with theautomatic sample changer. The slits were also replacedwith slits that can be remote-controlled.
The automatic sample changer consists of a movable table and six stages for cassettes. The cassettes
are designed for accepting sample containers. Biological samples are ﬁlled into one of the sample containers. Typical sample containers are, for example, 5cm-wide, 7.5-cm-high, and 1.25-cm-deep plastic boxes,
and approximately 3-, 6-, and 9-cm-diameter plastic
petri dishes. The sample containers are set into thecassettes, and then the cassettes are placed on thestages of the automatic sample changer. Seventeen
cassettes ﬁll one stage. The numbers of sample containers that can be set into the cassettes are from 4
to 12 according to the size of the sample containers.
Because most of the cassettes can contain more than
5 sample containers, the maximum number of sample
containers that can be automatically irradiated is morethan 500. The cassettes are circulated among stages bylifts and air cylinders placed both on the upstream anddownstream sides of the stages. One of the cassettes
is picked up by a transfer arm on the upstream sideof the topmost stage and carried to the beam position∗

Fig. 1. Schematic view of automatic sample changer together with range shifter. The side view and view fromdownstream are shown.

by a movable table. The cassettes are numbered, andthe cassette numbers are detected by detectors before
being picked up by the transfer arm. The slits are automatically positioned at a certain width determined by
the size of the sample containers indicated by the cassette number. The selections of absorber thicknesses
and doses are speciﬁed by two-dimensional bar codes
aﬃxed on the sample containers.
The automatic sample changer was used in experiments, and showed good performance.
Reference
1) H. Akiyoshi, N. Fukunishi, M. Kase, Y. Yano, T. Abe,and Y. Yoshida: RIKEN Accel. Prog. Rep. 36, 291(2003).

Formerly, H. Akiyoshi

245

RIKEN Accel. Prog. Rep. 39 (2006)

Design of rebuncher between RRC and fRC
T. Aoki,∗ O. Kamigaito, N. Fukunishi, N. Sakamoto, L. Stingelin, and A. Goto
The beam extracted from the RRC will be injectedto the fRC through a beam line of 100 m. The phasewidth of the beam keeps growing; the bunch length of
the beam becomes a twofold during the transport. In
addition, the fRC is operated at a frequency a threefold of that of the RRC. Therefore, a phase widthof ±5.0◦ during RRC extraction becomes ±29◦ during
fRC injection. Thus, injection becomes diﬃcult.
Therefore, a rebuncher between the RRC and thefRC is indispensable for improving injection eﬃciency.
It is required to keep the beam phase within ±7.5◦during fRC injection.
This rebuncher is also expected to regulate thechange in beam energy caused by the variation of the
thickness of the charge stripper after the RRC. For
this purpose (acceleration mode), gap voltage should
be as high as possible.
The basic parameters required for the rebuncher are1) installation position, 2) voltage, 3) frequency, and4) number of gaps. These parameters were determined
as described below.
First, the longitudinal motion of the beam was investigated to determine the position and voltage. Assuming a longitudinal emittance of an erected ellipseof ±0.06% in momentum and ±5◦ in phase for the output beam from the RRC,1) the position and the voltage
were determined so as to get the erected ellipse with aphase width of less than ±7.5◦ during the injection of
the fRC. To meet this condition, the position was determined 60 m downstream of the RRC. The required
voltage was 930 kV at RRC frequency.
Next, rebuncher frequency and gap number were determined. As is well known, the actual gap voltage is
proportional to the inverse of the harmonic number.
On the other hand, the phase width at the rebuncher
is proportional to the harmonic number. To keep thephase width less than ±30◦ , the harmonic number of
6 was chosen; the resonant frequency of the rebuncher
was 110 MHz. Furthermore, the gap number of 4 waschosen to reduce the required gap voltage; the designed
voltage was 38.8 kV. The length of the rebuncher was
1 m.
The rebuncher cavity was designed using the
MAFIA code. RF characteristics were evaluated forthe three cavity types shown in Fig. 1.
The results are shown in Table 1. The shunt
impedance Rs is deﬁned as follows:Rs =2

4(V1 + V2 )
,
2P

246

Table 1. RF characteristics of three cavity models shownin Fig. 1.

(1)where P is the power dissipation in the cavity. V1 and∗Fig. 1. Three cavity structures evaluated by MAFIA calculation; (A) interdigital H (IH) structure, (B) crossedbar H(CH) structure, and (C) adopted structure.

Department of Physics, School of Science, The Graduate
University of Tokyo

Type Rs [MΩ]Q
V2 /V1A
22.59
25760 2.43
B
38.82
25680 2.43
C
33.36
26095 1.24

V2 denote the end-gap voltage and center-gap voltage,
respectively.
Type (C) has the minimum voltage ratio V2 /V1 ,which means the peak electric ﬁeld can be reduced fora given total voltage (2 [V1 + V2 ]). This feature will be
useful for the acceleration mode. Another advantageof this type is that the electromagnetic ﬁeld does notexist in the lower half of the cavity, as shown in Fig. 2,
where the pumping port might be placed without the
disturbance of the resonant ﬁeld. Therefore, type (C)was adopted, although its shunt impedance is not thehighest.
The detailed design of the mechanical structure isunderway. At the same time, a 1/3-scaled model isbeing fabricated.
Reference
1) R. Taki: Master’s Thesis at Michigan State University(2003).

Fig. 2. Magnetic field distributions of fundamental modeof rebuncher cavity.

247

RIKEN Accel. Prog. Rep. 39 (2006)

Magnetic field measurements of RIKEN fRC
N. Inabe, N. Fukunishi, J. Ohnishi, H. Ryuto, S. Yokouchi, M. Nagase, E. Ikezawa, M. Kase,
A. Goto, Y. Yano, and T. Mitsumoto∗
RIKEN ﬁxed-Frequency Ring Cyclotron (fRC)1,2)
is a postaccelerator of the existing RIKEN Ring Cyclotron (RRC). Its role is to accelerate heavy ions suchas xenon and uranium up to 51 MeV/nucleon, which isessential for producing 350-MeV/n xenon and uranium
beams in the RIBF project. The isochronous magnetic ﬁelds of fRC are basically produced by iron poles
with a very detailed design.1) This scheme is possible
because fRC is a ﬁxed frequency machine and magnetic ﬁeld distributions are basically the same for allions, except for small diﬀerences between ions with different mass-to-charge ratio. To compensate for thesesmall diﬀerences, trim coils will be used in fRC, as wellas to compensate for the deformation eﬀects of magnet poles caused by vacuum and electromagnetic forces
and to correct harmonic ﬁelds produced by magnetic
inﬂection channels. Because these eﬀects are relatively
small, the number of trim coils and their maximum
excitation currents are signiﬁcantly reduced comparedwith frequency-tunable cyclotrons such as RRC and
IRC.3) As a result, the trim coils of fRC were designed
to correct only 2% of the magnetic ﬁeld distributions
as a whole. It means that 1% of unexpected error in amagnetic ﬁeld distribution is not acceptable in fRC.
The construction of fRC started in 2002 and its four
sector magnets were completed at the Niihama worksof Sumitomo Heavy Industries, Ltd. in March 2005.
In the ﬁnal stage of the fabrication, these four sector
magnets were initially assembled and precisely positioned as they will be positioned in the RIKEN site asa preparation of its ﬁnal assembly in RIKEN. Hence,
we carried out magnetic ﬁeld measurements of fRC at
Niihama works in March and April 2005.
We carried out various types of magnetic ﬁeld measurements. Radial distributions on hill centerlines were
measured for all sector magnets with various excitation currents. Radial distribution on the centerlineof S (South) valley and azimuthal distributions on anedge region of ES sector magnets were also measured.

In addition, stray ﬁelds from sector magnets were alsomeasured around the sector magnets. Figure 1 and Table 1 show the summaries of the position and methodsof magnetic ﬁeld measurements, respectively.
The magnetic ﬁeld distributions with the main coil
excitations were measured for various excitation currents. The distributions on the hill centerlines areshown in Fig. 2 for the 615 A of an excitation current,
which corresponds to uranium acceleration. The diﬀerences between the four sector magnets are less than 50
gausses for 615-A excitation. The diﬀerences becomelarge for 480-A excitation, but still remain within 80

Fig. 1. Plane ﬁgure of fRC. Labels from “A” to “E” represent the diﬀerent kinds of magnetic ﬁeld measurements.
For details, see Table 1. Circles show the positions
where measurement “E” was performed.

Table 1. Summary of magnetic ﬁeld measurements. The symbols δR and δθ indicate the interval between
successive two points in the measurements of radial and azimuthal directions, respectively.
Label
A
B
C

probe
NMR
Hall probe
Hall probe

Measured quantities
Radial distribution (δR = 20 mm)
Azimuthal distribution (δR = 50 mm, δθ = 5 mm)
Radial distribution (δR = 5 mm)

Excitation current (A)615, 550, 480, 350
615, 550, 480
615, 480

DE

NMR
3-axis hall meter

Radial distribution (δR = 5 mm)
Stray ﬁelds

615§ , 480§
0 ∼ 650§∗248

No.5 trim coil was excited to 100 A.

Sumitomo Heavy Industries, Ltd.

Fig. 2. Radial distributions of magnetic ﬁelds excited by
615 A.

gausses for the whole range of operation from 350-A
excitation to 615-A excitation. These small diﬀerences
can be corrected by bypassing power supplies for themain coils of the sector magnets. The diﬀerences inmagnetic ﬁeld proﬁle between observations and the design are also less than 50 gausses, which correspond to
0.3% of the magnetic ﬁeld. Because the present 0.3%
diﬀerence is not negligible for fRC, we estimated theexcitation currents of the trim coils under the assumption that magnetic ﬁeld errors averaged over equilibrium orbits are proportional to the errors on the hill
centerline. The results are summarized in Fig. 3. The
deviations from the design values for trim coil currents
are less than 20 A, which should be compared with the
maximum currents of the trim coils, 200 A for injection and extraction regions and 100 A for other regions.
The present deviations are acceptable if our assumption holds. To verify the present assumption, it is necessary to measure ﬁeld maps over the whole acceleration regions. However, we do not plan to measure ﬁeld
maps because a mapping apparatus is very expensive.
In addition, magnetic ﬁeld calculations give us goodstarting values of trim coil currents for actual acceleration because the accuracy of calculation is 0.3% asmentioned above. Our expectation is that these errors
are smoothed out in averaging over equilibrium orbits.
It is very diﬃcult to ﬁnd a mechanism for enhancing
the observed errors in orbit averaging.
Magnetic ﬁeld distributions in the edge and valley

Fig. 3. Estimation of trim coil currents for uranium acceleration. Trim coil currents are estimated on the basisof the observed magnetic ﬁelds of NE and NW sector
magnets compared with the design value.

region are also reproduced well by our magnetic ﬁeld
calculations. Stray ﬁelds from sector magnets produce
30 gausses for increasing the currents of the main coils.
The present data will be used to determine the thickness of magnetic shields for devices such as a ﬂow
switch, which do not work properly even under very
low magnetic ﬁelds. In the magnetic ﬁeld measurements at Niihama works, we obtained very few dataon magnetic ﬁelds excited by trim coils. We plan tomeasure the magnetic ﬁelds on the hill centerlines excited by the trim coils at RIKEN because saturation
properties for exciting trim coil currents are also important information in actual acceleration. These measurements will be performed next spring.
References
1) N. Inabe et al.: Proc. 17th Int. Conf. on Cyclotrons
and Their Applications, Tokyo, 2004-10 (Japan Particle
Accelerator Physics Society, 2005), p. 200.
2) T. Mitumoto et al.: Proc. 17th Int. Conf. on Cyclotrons
and Their Applications, Tokyo, 2004-10 (Japan Particle
Accelerator Physics Society, 2005), p. 384.
3) J. Ohnishi et al.: Proc. 17th Int. Conf. on Cyclotrons
and Their Applications, Tokyo, 2004-10 (Japan Particle
Accelerator Physics Society, 2005), p. 197.

249

RIKEN Accel. Prog. Rep. 39 (2006)

Construction of the rf resonators for the fRC
N. Sakamoto, O. Kamigaito, S. Kohara, A. Goto, N. Inabe, M. Kase, and Y. Yano
In-ﬂight radioisotope beam production with uranium (350 MeV/u) is one of the most important issuesof the RIBF. A four-sector ring cyclotron, fRC, hasbeen designed and built to realize an uranium acceleration scheme.1) The beam frequency (fbeam ) fromthe injector RRC is 18.33 MHz. A high energy gain of
1 MV/turn at an extraction radius is required to obtaina large turn separation.
The fRC has two acceleration resonators, namely, Eand W-resonators. The design value of the acceleration
voltage is 500 kV/resonator. Since it has been decided
to utilize an existing 100 kW ampliﬁer,2) the parallel
shunt resistance is required to be larger than 1.25 MΩ.
Due to the limitation of space, the single-gap-type
resonator with the frequency (ff rc ) of the third harmonic of fbeam is chosen, while the rf frequency of theinjector RRC (fRRC ) is 18.33 MHz, Therefore, ﬂat-top
systems, which broaden the longitudinal acceptance,
are necessary. The design parameters of the rf resonators are summarized in Table 1.
The construction of the acceleration resonators
started in 2003. A schematic of the resonators is shownin Fig. 1. The rf power is fed through an inductive loop
feeder. Block tuners are used to tune the resonant frequency by ∆f /f ∼ 1%. The rf characteristics of theresonators have been investigated and optimized usinga three-dimensional code, MAIFA.

This year, the fabrication was ﬁnished and lowpower tests were performed. The frequency of the resonator is shown with Q-values in Fig. 2. A frequencyof 54.99 MHz is not covered. Some modiﬁcation of thecavity is required. Otherwise the operational frequency
decreases by 1%. The parallel shunt resistance of theresonator was also measured by a perturbation method
and is as large as 1.5 MΩ. The required rf power will
be approximately 85 kW. The measured rf characteristics are summarized in Table 2. The Q-values andthe parallel shunt resistances are approximately 60%of the calculated ones. The ﬁnal stage ampliﬁer is of
the grounded grid type using a tetrode (RS2058CJ)
power tube. The maximum output power is 100 kW ata frequency of 54.99 MHz.
The frequency of the ﬂat-top resonator is 3·facc andthe maximum gap voltage is 180 kV. The maximum
wall loss is 20 kW. The ﬂat-top resonator is underconstruction. The construction of the ampliﬁer forthe ﬂat-top resonator, which is also of the grounded
grid type based on the 4CW5000E tetrode tube, hasalready been ﬁnished. The commissioning of the rf
system is planned to start in April 2006.

Table 1. Key parameters of rf characteristics.
Resonator
Frequency [MHz]No. of resonators
Gap
Maximum gap voltage [kV]Wall loss [kW]Tuner∆f /f [%]

acceleration ﬂattop
54.99
164.972
1single gap
500
180
85
15
Block Tuner
1.5
2.5

Fig. 2. Frequency and Q-value plots.

Table 2. Rf characteristics of acceleration resonators. The
block tuners are set at 100 mm.
Res #
E
W

frequency[MHz]
54.57
54.52

Q
26120
27200

Rs[MΩ]
1.46
1.53

References
1) N. Inabe et al.: Proc. 17th Int. Conf. on Cyclotrons
and Their Applications, Tokyo, 2004-10 (Particle Accelerator Society of Japan, 2005), p. 200.
2) Y. Murakami et al.: Proc. 12th Symp. on Accelerator
Science and Technology, Wako, 1999-10 (1999), p. 239.
Fig. 1. Schematic drawing of acceleration cavity.

250

RIKEN Accel. Prog. Rep. 39 (2006)

First cool down and excitation test of superconducting sector
magnets for SRC magnets
H. Okuno, J. Ohnishi, K. Yamada, H. Hasebe, T. Maie, K. Ikegami, A. Goto, M. Kase, and Y. Yano
In August 2005 the assembling of superconducting
sector magnets for the SRC1) was completed as shownin Fig. 1. After that we performed the first cool down
and excitation test until Nov. 7, 2005. The historyof the first cool down and excitation test is shown in
Table 1. We turned on the main compressors on Aug.
30, 2005, and continued the purification of the cryogenic system until Sept. 17 to remove impurities suchas oxygen, nitrogen and water among others in heliumgas at less than 0.5 ppm. The cool down started on
Sept. 19, and finished on Oct. 13 for the first time
as shown in Fig. 2. The coils and supporting structures were cooled by temperature-controlled helium
gas, which was supplied by tuning the inlet valves ofthe four turbines and bypass valves that were installed
to skip each turbine. All the main coils became superconducting state on Oct. 13 at about 1:00AM when the
supply gas temperature was 8.4 K and the coil outlet
temperature was 9.6 K. The cool down was successfullycompleted within 24 days. After the cool down, the excitation test of the superconducting coils started from
Oct. 21.2) The coil currents were increased daily, checking reactions between the power supply and cryogenic
system. On Nov. 7 all the coils were fully excited togenerate the maximum field of 3.8 T. The maximum

currents are 5000 A for the main coil and 3000 A forthe superconducting trim coil. The fast and slow down
tests were performed at various currents. Data analysis is now in progress.

Fig. 2. First cool down curves of SRC. The curves showtemperatures (SM1) of the main coil vessels (TI A1P0,
TI A1P02), connecting plates (TI A1P03), He supply(TI A1P04), He return (TI A1P05A, TI A1P05B) andthe superconducting trim coils (TI A2P01, TI A2P02).
A prediction from a simple calculation is also shown in
the graph.

Table 1. History of first cool down and excitation test.

References

Fig. 1. Photo of SRC.

1) H. Okuno et al.: Proc. 17th Int. Conf. on Cyclotorons
and Their Applications, Tokyo, 2004-10 (Japan Particle
Accelerator Physics Society, 2005), p. 373.
2) J. Ohnishi et al.: RIKEN Accel. Prog. Rep. 39, 252(2006).

251

RIKEN Accel. Prog. Rep. 39 (2006)

First excitation of the SRC superconducting sector magnets
J. Ohnishi, H. Okuno, K. Yamada, M. Nagase, K. Ikegami, H. Hasebe, T. Maie, N. Fukunishi,
M. Kase, A. Goto, and Y. Yano
Each of the SRC sector magnets has a pair of superconducting main coils and four pairs of superconducting trim coils. Their power supply system is composedof one power supply for the main coils, four power supplies for the trim coils, and fourteen auxiliaries used forthe adjustment of the magnetic ﬁeld among the sector
magnets.1) The nominal currents are 5000 A for themain coils and 3000 A for the trim coils, respectively.
The SRC sector magnets were cooled to the liquid helium temperature for one month from September 19,
2005.2)
Excitation of the sector magnets was started on October 21. Firstly, the current control of the power supplies was conﬁrmed to be normal by monitoring thevoltage ripples while the main coil and the trim coils
were excited in turn up to 1000 A. The current ramping rates were 1 A/s for the main coils and 5 A/s forthe trim coils. However, the rate was set to be 0.5 A/sfor the main coil to suppress the temperature rise of
the trim coils due to the eddy current loss to within
0.2 K.
Secondly, the tests for quench protection of the superconducting coils were performed at the main coilcurrents of 1000 A and 3000 A. In the tests, the coils
are disconnected from their power supplies and coilcurrents are discharged rapidly with dump resistors(fast discharge test). The sequence and time lag in the
disconnection of the power supplies and the damping
time of the coil currents were conﬁrmed to be designedby measuring the voltages and currents of all coils. Figure 1 shows waveforms of the voltages generated in themain and trim coils. In the fast discharge test in which
the main coil current of 3000 A was damped with a resistor of 0.3 Ω, the voltage waveform of the main coil,which corresponds to that of the coil current, was inagreement with the calculated one in which the changeof the coil inductance was taken into account. The parameters of the quench detection were set as follows:
voltage greater than 0.5 V was generated for longer
than 0.5 s in one of the main coils; voltage greater than
0.1 V was generated for longer than 0.5 s in one of thetrim coils.
On November 6, after the tests at a low current level,
the main coils were successfully excited up to 5000 A
without quenching. On the following day, the currentof the four trim coils was increased to the nominal current of 3000 A in turn under a condition in which themain coil was excited at 5000 A. As a result, the full
excitation of all coils was achieved. Figure 2 shows an
excitation curve of the sector magnet as a function of
the main coil current. The position of the measurement was 5.45 m from the center of the SRC on thecenterline of the sector magnet near the last circulating orbit. Figure 3 shows the magnetic ﬁeld distribution measured tentatively with a Hall probe along thecenterline of sector magnet SM5 when the main coil
was excited to 5000 A and four trim coils were excited
to 3000 A. The data are in agreement with the resultsof TOSCA calculation within 0.5%.
The coil current was increased while monitoring themagnetic force acting on the coils using 208 strain
gauges attached to the coil vessels and their thermallyinsulated supports. The strength of the electromagnetic force in the radial direction is shown in Fig. 4.
The measured values are in agreement with the results
calculated by TOSCA, and they are smaller than thedesign strength of 900 kN in the radial supports of thecoils. On the other hand, the electromagnetic forces inFig. 1. Voltages generated in the main and trim coils in thefast discharge test when only the main coil is excited at
3000 A. The voltages for the trim coils are plotted by
ten times.

Fig. 2. Excitation curve of the superconducting sector magnet.

252

Fig. 3. Magnetic field distribution along the centerline of
sector magnet SM5. The currents are 5000 A and3000 A for the main coil and the four trim coils, respectively.

Fig. 4. The magnetic force acting on a pair of main coils(cold mass) in the radial direction. This was measured
with strain gauges attached to the radial support.

the maximum current will be performed, followed bymagnetic ﬁeld mapping for about three months.
the azimuthal and vertical directions were balanced,
and no large one-sided force was detected in their supports.
The excitation tests were terminated due to the leakage of the thermal insulation vacuum on November 8.
After repair and re-cooling, the measurement of thecurrent stability and the test for fast damping from

References
1) J. Ohnishi et al.: RIKEN Accel. Prog. Rep. 36, 301(2003).
2) H. Okuno et al.: RIKEN Accel. Prog. Rep. 39, 251(2006).

253

RIKEN Accel. Prog. Rep. 39 (2006)

Present status of liquid-helium supply and recovery system
K. Ikegami, H. Okuno, T. Yoshida, K. Nakano, T. Maie, H. Hasebe, H. Fukuda, M. Nakamura, and M. Kase
The liquid-helium supply and recovery system,1)
which can generate liquid helium at a rate of 200 /hfrom pure helium gas, has been stably operated since
the beginning of April 2001. The volumes of liquid
helium supplied per year are listed in Table 1. The
volume supplied has gradually increased over the years
since 2001.
Figure 1 is a schematic diagram of the liquid-helium
supply and recovery system.
An impure gas cadre with a volume of 1800 m3 wasadded to the system at the beginning of April because
the volume of recovered helium gas increased. At the
beginning of August, the turbine which is indicated as
T1 in the figure was replaced by a new one, because theT1 turbine broke down after approximately 3500 hoursof operation. Two types of compressor for recoveringand liquefying helium gases were overhauled due toregulations on high-pressure safety and were inspectedby the high-pressure gas safety institute of Japan.
To measure the helium purity and gas flow rate of
the recovered helium gas, a recovery helium gas ob-

servation system is being built on Wako campus. The
recovery helium gas observation system consists of acontrol system placed in the liquid-helium supply andrecovery building and five recovery stations, which areequipped with a helium purity sensor and a gas flow
meter. The recovery stations are indicated on the
Wako campus map shown in Fig. 2. The first recovery
station is near the cooperation center building for theadvanced device laboratory located on the south sideof the RIKEN campus. The second recovery station isin front of the chemistry and material physics building for the nanoscience project. The third recovery
station is in the RIKEN main research building andis connected to the frontier research building and thefrontier material research facility building. The forthrecovery station is behind the east brain science building. The fifth recovery station will be located between
the Nishina memorial building and the RIBF accelerator building. Each station is connected to the control system through optical fiber cables. Information
regarding helium purity and gas flow rate among others can always be accessed at the liquid-helium control
room.

Table 1. Volumes of liquid helium supplied per year from2001 to 2004.
Year
2001
2002
2003
2004

Amount of supplied liquid helium (k)
28
40
52
55

Fig. 2. Map of recovery stations on Wako campus. The
1 to 
5 in the figure.
recovery stations are indicated as Reference
Fig. 1. Schematic diagram of liquid-helium supply and recovery system.

2541) K. Ikegami et al.: RIKEN Accel. Prog. Rep. 34, 349(2001).

RIKEN Accel. Prog. Rep. 39 (2006)

Power supplies for magnets in RARF/RIBF
A. S. Banerjee,∗ M. Nagase, E. Ikezawa, J. Ohnishi, and M. Kase
A magnet power supply system is one of the main
constituents of an accelerator facility. Precise and stabilized DC power supplies for excitation of coils of DC
magnets are required for Accelerator application in order to have a high-quality beam output as requiredfor various experiments. A large number of DC power
supplies used in RARF/RIBF are shown in Table 1.
A list of typical DC magnet power supplies is given
in Table 2. Some power supplies have been used formore than 26 years, whereas the power supplies for
RIBF have been fabricated recently. The diﬀerences
between new and old ones will be reported.
These power supplies are basically current-regulated
DC power supplies. The current rating of these power
supplies varies from 5 to 5200 A required for various
applications of the accelerator system. The current
stability of these power supplies is an important factor
as it has direct impact on the stability of the magnetic
ﬁeld and hence the stability of the beam. The required
current stability depends on the function of the magnet
concerned. The current stability must be less than
5 ppm is required for the power supplies for the main
coil in the cyclotron sector magnets.
In the old power supplies, stability degradation due
to changes in the characteristics of a resistive-type
feedback current sensor has been noted. The resistivetype current sensor was directly cooled by water andthe temperature is controlled to 35 ± 1◦ C to avoid avariation of characteristics with temperature. Howevera change in their characteristics has taken place due tocorrosion. This has degraded the stability of the power
supply. To solve this problem DC current transformer(DCCT) sensors have been used in place of the resis-

Table 1. Number of DC power supplies for magnets in
RARF/RIBF.

∗

Visiting Scientist from VECC, India

tive type sensor. DCCT sensors do not require coolingas the current is sensed by magnet coupling.
In a current feedback loop of old power supplies, a
DAC and DC ampliﬁer are enclosed in a box, which
is heated to 45◦ C using a thermostat-controlled ovento avoid changes in the characteristics of the elements
which eﬀect the current stability. However, in thismethod, the surface temperature of several sensitiveelements rises over a value much higher than 45◦ C.
Frequent failure of some elements is noted at this temperature. To solve this problem, Peltier coolers areused, which are able to keep the temperature at a low
value of 25◦ C. It may be noted that the burden resistor
of DCCT is also kept in the Peltier cooler.
The combination of the DCCT current sensor and
the Peltier cooler gives a long-term stability of around
5 ppm to a DC power supply. The new power supplies in RIBF have been designed on the basis of thiscombination. The old power supplies in RARF should
also be modiﬁed accordingly. Already, the modiﬁcation is incorporated in 21 old power supplies including
the power supplies for the cyclotron’s main coils.
The SRC is a large-scale superconducting device,
which was introduced to the facility for the ﬁrst time.
When a quench occurs in the superconducting coil, a
special circuit is very important in protecting the coilfrom damage. A diagram of the SRC main coil power
supply1) is shown in Fig. 1. The power supply must
discharge the energy stored in the coil by decreasing
the coil current rapidly within 60 s (time constant of
the main coil) through a pair of dump resistors (R1 in
Fig. 1) so that the temperature rise of the coil by Joul
heating and the voltage generated are maintained at
an acceptable level to protect the coil from both thermal and insulation damages. A slow discharge scheme
is also adopted to discharge the current within 1200 s
for any other fault in the power supply and cryogenic
cooling system to avoid loss of liquid helium due toeddy current in the fast discharge.

Fig. 1. Diagram of SRC main coil power supply.

255

Table 2. List of typical power supplies in RARF/RIBF.

Both linear mode and switching mode power supplies are used. Linear (i.e., transistor-dropper)-mode
power supplies are generally bulky and especially low
in eﬃciency because of considerable power loss in theirseries pass element, although they are simple in design and have no high frequency noise problem. Recent advances in semiconductor, magnetic and passive technologies have made switching power supplies
an ever more popular choice in the power conversion arena. Switching power supplies are smaller andhave higher eﬃciency, of the order of around 90%.
Using the proper shields and noise ﬁlters has solved
the high-frequency noise problem in a switching-mode
power supply. Moreover, for a high DC current requirement, switching-mode power supply modules canbe stacked in parallel conveniently with equal current
sharing among the modules. Hence, the choice for all
future DC power supplies will be of the switching mode

256

type.
Computer interfaces are incorporated in these power
supplies for controlling and monitoring them from a remote control room. In the very early stage, GPIB waschosen as interfaces in RILAC. In RARF, the original
RIKEN CIM-DIM system has been used. New power
supplies, fabricated after 2000, have been designed using commercially available network IO (NIO). In thecourse of changing the old power supplies, old interface are being converted into NIO. In RARF/RIBF,
two kinds of interfaces, CIM-DIM and NIO will be usedin the future.2)
References
1) J. Ohnishi et al.: RIKEN Accel. Prog. Rep. 36, 301(2003).
2) M. K. Komiyama et al.: RIKEN Accel. Prog. Rep. 38,
256 (2005).

RIKEN Accel. Prog. Rep. 39 (2006)

Status of beam transport line from SRC to BigRIPS
K. Kusaka, T. Kubo, Y. Mizoi,∗1 and N. Kakutani∗2
In the RI-Beam Factory (RIBF) project, energetic
heavy-ion beams from the SRC will be delivered tothe projectile fragment separator, called BigRIPS,1)
to produce RI beams. The beam transport line fromthe SRC to the BigRIPS has been constructed on thebasis of a design study reported elsewhere.2)
A layout of the beam line, together with the SRC
and the BigRIPS separator, is schematically shownin Fig. 1. A primary beam extracted from the SRC
is transferred from the SRC room to the IRC room
using a quadrupole quartet (QQ). A beam shutter isinstalled in the wall between the SRC room and the
IRC room for tuning of the SRC. In the IRC room, adipole magnet, D1, changes the direction of the beamby 20◦ together with quadrupole multiplets, TQ and
DQ. A pair of beam steering magnets are also installed
after the DQ. The beam is then transported to the BigRIPS target using two 50◦ dipole magnets (R1-D1
and R1-D2), a quadrupole doublet (R1-DQ), and two
quadrupole triplets (R1-TQ1 and R1-TQ2).
In Table 1, the main parameters of the dipoles arelisted. It should be mentioned that the two dipoles R1D1 and R1-D2 are 2-Tesla normal conducting bending

magnets.3)
For the quadrupoles, we have constructed 5 types ofquadrupole magnet as listed in Table 2. Q420a is abuilding block used to form the quadrupole multiplets
QQ, TQ, DQ, and R1-DQ, and its design has beenreported elsewhere.4)
Q220 and Q420, with a maximum field gradient of
24 T/m, form the quadrupole triplet R1-TQ1. All
these quadrupole multiplets have a bore diameter of
70 mm. On the other hand, the bore diameter of thequadrupole triplet R1-TQ2, consisting of Q400 and
Q800, is 110 mm, so that the primary beam is focusedon the target with a small spot size.
The fabrication of these magnets and their power
supplies started in 2004 and finished in the early summer of 2005. All the magnets were successfully tested
and magnetic field measurements were performed at
the factory. They have been installed in the RIBF
building together with power supplies and vacuum
chambers for beam diagnosis (see Figs. 2–4). All cabling and plumbing, including installation of beamducts and vacuum evacuation systems, finished in thesummer of 2005. Excitation tests of the magnet system and evacuation tests of the vacuum system weresuccessfully performed.
A radiation shield wall between the beam line elements and the IRC has also been constructed (Fig. 5).
It consists of a 500-mm-thick iron wall and concrete

Table 2. Main parameters of quadrupoles.

Fig. 1. Schematic layout of beam line from SRC to BigRIPS target.

Max. Field Gradient [T/m]Bore Diameter [mm]Yoke Length [mm]Current [A]Coil Resistance [mΩ]
Weight [kg]Q420a Q220 Q420 Q400 Q800
15
24
24 17.5 17.5
70
70
70 110 110
420 220 240 400 800
160 240 220 390 350
146 152 219 124 269
350 380 650 1950 3700

Table 1. Main parameters of dipoles.

Max. Field [T]
Bending Angle [degree]
Bending Radius [mm]Pole Gap [mm]Current [A]Coil Resistance [mΩ]
Weight [ton]
∗1
∗2

D1
1.6
20
5000
60
320
175
12

R1-D1/D2
2.0
50
4020
60
650
205
39

Osaka Electro-Communication University
Toshiba Corporation

Fig. 2. Beam shutter, installed in wall between SRC and
IRC room, together with quadrupole triplet TQ.

257

Fig. 3. 2-Tesla dipole R1-D1 and quadrupole triplet R1TQ1. Shielding blocks can also be seen behind R1-D1.

Fig. 5. Radiation shield wall and IRC.

blocks. The iron part consists of approximately 430
plates of steel with a thickness of 22 mm. The concrete
blocks are of rectangular shape with a square crosssection; 24 pieces of concrete blocks form the 500-mmthick wall behind the iron wall.
References

Fig. 4. Large-bore quadrupole triplet R1-TQ2.

2581) T. Kubo et al.: RIKEN Accel. Prog. Rep. 39, 259(2006).
2) K. Kusaka et al.: RIKEN Accel. Prog. Rep. 35, 297(2002).
3) T. Nagafuchi et al.: RIKEN Accel. Prog. Rep. 33, 234(2001); Y. Mizoi et al.: RIKEN Accel. Prog. Rep. 35,
305 (2002).
4) N. Fukunishi et al.: RIKEN Accel. Prog. Rep. 34, 329(2001).

RIKEN Accel. Prog. Rep. 39 (2006)

Status of BigRIPS separator project
T. Kubo, K. Kusaka, K. Yoshida, A. Yoshida, T. Ohnishi, N. Fukuda, M. Ohtake, Y. Yanagisawa, H. Sakurai,
T. Motobayashi, and Y. Yano
The BigRIPS separator1) and phase-I RI-beam delivery line2) are under construction for the RI beamfactory (RIBF) project with the aim of being commissioned in early 2007. Figure 1 shows a schematic layoutof the BigRIPS separator and delivery line along with
the RIBF cyclotrons.
The BigRIPS separator is designed to be a superconducting in-ﬂight separator employed for the production
and separation of RI beams. It is characterized by
two major features: large acceptances and a two-stage
separator scheme. The large acceptances are achieved
using large-aperture superconducting quadrupoles, allowing the eﬃcient production of RI beams using the
in-ﬂight ﬁssion of uranium beams as well as projectile
fragmentation. The two-stage separator scheme makes
it possible to deliver tagged RI beams as well as to realize two-stage isotopic separation. In the RI-beamtagging mode, the ﬁrst stage of the BigRIPS separator
serves to produce and separate RI beams, while thesecond stage is employed to identify RI-beam species
in an event-by-event mode.
The BigRIPS separator is followed by the phase-I
RI-beam delivery line, which serves to transport RI
beams to experimental setups placed downstream. The
delivery line is designed to work also as a zero-degree
forward spectrometer called ZDS.2) In this operationalmode of the delivery line, ZDS is employed to analyze
and identify projectile reaction residues in secondaryreaction studies of the RI beams.
The fabrication of the BigRIPS magnets consisting of fourteen superconducting triplet quadrupoles(STQs)3,4) and six room-temperature dipoles was ﬁnished in a Toshiba factory in 2004. All the magnets
were successfully tested oﬀ-line in the factory before
being shipped to RIKEN. The ﬁrst-stage magnets con-Fig. 1. Schematic layout of RI beam factory in 2007. The
BigRIPS separator and phase-I RI-beam delivery line
are shown along with the RIBF cyclotrons.

sisting of ﬁve STQs and two dipoles were installed in
the BigRIPS hall in 2004, along with the liquid-helium
cryogenic plant.5) The installation of the second-stage
magnets, which is presently under way, will be completed in March 2006. Field-map measurement is being prepared for some of the second-stage STQs anddipoles. We plan to perform an on-line excitation testof all the magnets in April 2006.
The cryogenic plant6) is employed to cool the ﬁrststage STQs by supplying liquid helium and 70 K gas
helium in a refrigeration mode through a transfer line
system. From 2004 to 2005, the test operation of thecryogenic plant has been carried out several times in
diﬀerent operational modes and conditions. The cooling capacity of the cryogenic plant has been measured
to be approximately 510 W at liquid helium temperature by a stand-alone operation of the refrigerator. The
thermal heat load of the transfer line system, which
consists of a joint box, a 50-m-long transfer line andﬁve valve boxes, has been measured to be approximately 100 W in a test operation in which the connection tubes between the valve boxes and the STQs
were bypassed. In this case, the liquid and 70 K gas
helium coming out of the valve boxes directly returnedto the transfer line without going into the STQs. The
measured heat load of the transfer line system was initially found to be much larger than this value, because
the 70 K thermal shields were not properly fabricatedin some parts of the transfer line and because of asmall vacuum leakage in a cryogenic valve. The headload of 100 W has been achieved after repairing thosefaults. In combination with the results of the oﬀ-line
test of the STQs, the total heat loads to the cryogenic plant have been estimated to be approximately
210 W: 100 W for the transfer-line system, 20 W for the
STQs and 90 W for cooling the current leads. Hence,the cryogenic plant has the extra cooling capacity of
approximately 300 W. This will be employed to copewith the heat loads caused by the neutron radiationfrom the production target and the beam dump of the
BigRIPS separator.
The test operation to cool down the ﬁrst-stage STQs
was carried out in late 2004. It took approximately
three weeks to cool the ﬁve STQs down to liquidhelium temperature from room temperature. The next
cooling-down operation is scheduled in early 2006 in order to make an on-line excitation test of the STQs anda simulation test of the radiation heat loads. We plan
to start continuous operation of the cryogenic plant insummer 2006.
The STQs of the BigRIPS second stage are cooled259

by a small refrigeration system, which is mounted on
the cryostat of each STQ.3) The system consists of aGM cryocooler to cool 70 K shields and a GM/JT cryocooler to recondense evaporating helium gas in thecoil vessel of the STQs. The precooling using liquid
nitrogen as well as liquid helium is needed to makethe cryocoolers operational. The second-stage STQs
have been precooled at RIKEN since they were shipped
to RIKEN after being warmed up. It takes about
eight days to precool each STQ. Most of the STQs arepresently kept at liquid-helium temperature by continuous operation of the cryocoolers. Figure 2 shows aphotograph of those STQs.
The focal-plane chambers, which are to be placed at
the eight focuses of the BigRIPS separator, have been
fabricated along with their vacuum pump system. The
focal-plane chambers are equipped with focal-plane devices such as the slit system, the energy-degrader system, the foil/target ladder system, and the detector
stand system. They are to be used for isotopic separation, RI-beam tagging and beam diagnoses, in combination with beam-line detectors mounted on the detector stands.7) With respect to the beam-line axis,
the position of the focal-plane devices is adjustable byremote control. For some devices, only the in/out position can be controlled. Testing of the control system
is in progress for the focal-plane devices and the vacuum pump system. The installation of the focal-planechambers into the BigRIPS beam line is scheduled inearly 2006.
The beam-line detectors are presently being fabricated or designed. They are mounted in the focal-planechambers to measure the position and angle, energy
loss, and time-of-ﬂight (TOF) of RI beams. A delayline parallel-plate avalanche counter (DL-PPAC)8) is
employed to measure the position and angle. A mul-Fig. 2. Photograph of second-stage STQs. They were precooled and kept at liquid-helium temperature by continuous operation of the cryocoolers mounted on thecryostat of the STQs, and are awaiting installation into
the BigRIPS beam line.

260

tisampling ion chamber (MUSIC) with tilted foil electrodes9) is employed for the energy loss measurement,
while a thin plastic scintillation counter is employed for
the TOF measurement. The data acquisition systemof the beam-line detectors has been designed.
The production target and beam dump of the BigRIPS separator are exposed to the high heat loads
from primary heavy-ion beams. The maximum beam
power is as high as 83.3 kW, corresponding to the caseof a 238 U beam at 350 MeV/nucleon and 1 pµA. To
cope with such a high heat load, a rotating-disk target system cooled by water has been developed for the
production target.10) A water-cooling scheme using a
Cu screw tube and a Cu swirl tube has been adopted
for the beam dump, because those tubes signiﬁcantly
improve the heat transfer coeﬃcient of water ﬂow, sothat the temperature of the beam dump can be reduced.11) Final detailed designs of the target and thebeam dump system, based on a heat-load simulation
by ANSYS code, are in progress. They will be fabricated by March 2006.
A ﬁnal design of the radiation shields for the BigRIPS ﬁrst stage is in progress. The radiation shields
consist of approximately 200 concrete blocks and someiron blocks, and the total weight amounts to approximately 4000 tons. They will be fabricated and installedby autumn 2006.
The RI-beam delivery line consists of ten STQs
and two dipoles, which have the same designs as thesecond-stage magnets of the BigRIPS separator. The
fabrication and installation of those magnets will beﬁnished in March 2007. The focal-plane chambers forthe delivery line are also presently being fabricated.
References
1) T. Kubo: Nucl. Instrum. Methods Phys. Res. B 204,
97 (2003).
2) Y. Mizoi et al.: RIKEN Accel. Prog. Rep. 38, 297(2005).
3) K. Kusaka et al.: IEEE Trans. Appl. Supercond. 14,
310 (2004).
4) K. Kusaka et al.: RIKEN Accel. Prog. Rep. 37, 297(2004).
5) K. Kusaka et al.: RIKEN Accel. Prog. Rep. 38, 291(2005).
6) T. Kubo et al.: RIKEN Accel. Prog. Rep. 36, 316(2003).
7) K. Yoshida et al.: RIKEN Accel. Prog. Rep. 38, 293(2005).
8) H. Kumagai et al.: Nucl. Instrum. Methods Phys. Res.
A 470, 562 (2001).
9) K. Kimura et al.: Nucl. Instrum. Methods Phys. Res.
A 538, 608 (2005).
10) A. Yoshida et al.: RIKEN Accel. Prog. Rep. 38, 296(2005).
11) Y. Mizoi et al.: RIKEN Accel. Prog. Rep. 36, 318(2003).

RIKEN Accel. Prog. Rep. 39 (2006)

Design of rf-linacs of new injector to RIKEN Ring Cyclotron
O. Kamigaito, N. Fukunishi, T. Nakagawa, H. Saito, and A. Goto
The recent success in the synthesis of the superheavy element (SHE)1) using the RILAC (RIKEN
linear accelerator) - CSM (charge-state multiplier) GARIS (gas-ﬁlled recoil ion separator) system strongly
encourages us to further pursue the search for heavier SHEs and to more extensively study physical andchemical properties of SHEs. This compels us toprovide a longer machine time for these experiments.
However, the SHE research and RIBF research conﬂictwith each other, because both of them use the RILAC.
Therefore, a new additional injector linac to the
RRC has been proposed, which will make it possible
to concurrently conduct the SHE and RIBF researchstudies. The new injector, which will be placed in the
RRC vault, will be used exclusively to produce primarybeams of 350 MeV/u from the SRC.
The injector is designed to accelerate ions with amass-to-charge ratio of 7, aiming at heavy ions such as136
Xe20+ and 238 U35+ , up to an energy of 680 keV/uin the cw mode. It consists of an ECR ion source of
18 GHz,2) a low-energy beam transport (LEBT) section including a buncher, an RFQ linac based on thefour-rod structure, and three drift-tube linacs (DTL)
based on the quarter-wavelength resonator (QWR).
The rf-resonators are operated at a ﬁxed rf-frequency,
like the fRC. Strong quadrupole magnets will beplaced into the beam line between the rf-resonators.5)
The output beam is injected to the RRC withoutcharge stripping.
A schematic drawing of the rf-linacs is shown in
Fig. 1. The input energy to the RFQ is chosen to be
4 keV/u; the maximum extraction voltage of the ion
source is 28 kV. In order to increase the acceleration
gradient in the injector, the resonant frequency of theresonators is set to be 36.66 MHz, which is twice therf frequency of the RRC. The input beam is bunchedin the RRC frequency (18.33 MHz) before entering theRFQ. This helps to reduce the beam loss caused by
the higher rf-mode operation of the injector linacs.
The parameters of the RFQ were determined using the PARMTEQ code. By compromising the RFQ
length and defocusing force in the ﬁrst DTL, the output energy of the RFQ was set to be 100 keV/u. The
input emittance was assumed to be 200π mm·mrad at
4 keV/u, which corresponds to a normalized value of
0.6π mm·mrad.2) The main parameters are listed inTable 1.
The parameters in Table 1 are similar to those used
in a four-rod RFQ constructed by NISSIN Electric Co.,
Ltd. in 1993.3) The measured shunt impedance of thisRFQ, which has a vane length of 222 cm and a resonant
frequency of 33.3 MHz, is 47.6 kΩ. On the basis of thisshunt impedance, the estimated power loss in our RFQ
is about 20 kW.
The buncher in the LEBT section is one of themost important components in the injector. The
PARMTEQ simulation shows that nearly 80% of the
input beam is captured in the required rf-buckets of
18.33 MHz when the buncher is used, whereas the capture eﬃciency is less than 50% without it. It was also
found that the phase width and energy width can be
reduced signiﬁcantly with the buncher, as shown in
Fig. 2. The detailed design of the buncher as well as
the study of the LEBT system is under way.
The DTL parameters are optimized by calculating
the beam dynamics and rf-characteristics alternatively.
A computer program, developed for the CSM design,4)is used for the beam tracking simulation, whereas thecomputer code MAFIA is used for the estimation of
the rf-power consumption.
The beam envelopes in the DTLs are shown in Fig. 3,
which were calculated for the designed output beam

Table 1. Design parameters of RFQ.

Fig. 1. Schematic drawing of rf-linacs of new injector. DQ
and TQ stand for quadupole doublet and quadupole
triplet, respectively.

Frequency (MHz)Duty
Mass-to-charge ratio (m/q)
Input energy (keV/u)
Output energy (keV/u)
Input emittance (mm·mrad)
Vane length (cm)Intervane voltage (kV)
Mean aperture (r0 : mm)
Min. aperture (a: mm)
Max. modulation (m)Beam margin
Focusing strength (B)Max. defocusing strength (∆rf )Final synchronous phase

36.6
100 %
7
4
100
200 π
214
42.2
7.98
4.55
2.41
1.35
6.8
−0.225−30◦

261

make the magnet length as short as possible; this isimportant in preventing the phase width of the accelerated beam from spreading widely. The design ofthese strong quadrupole magnets is described in thefollowing paper.5)
The designed structure of the DTLs is similar tothat of the CSM resonators.4) The inner diameter ofthe resonators ranges from 0.8 to 1.1 m, depending on
the beam energy. The maximum electric ﬁeld on thedrift tubes is kept below 1.2 Kilpatrick. Table 2 shows
the main parameters of the DTLs. The power losses estimated with the MAFIA code ranges from 6 to 17 kW,
as shown in the table.
The required rf-power of the ampliﬁers will be
30 kW, considering the estimated power losses mentioned above and the deterioration of the quality factors of the real resonators. The ampliﬁer of the present
FC-RFQ, which has a maximum output of 40 kW, canbe referred to as a guideline for the ampliﬁer design.
Fig. 2. Longitudinal distribution of output beam of RFQ
simulated using PAMTEQ code. A buncher in the
LEBT section was included in the simulation, where
the position of the buncher was assumed to be 2 m upstream of the RFQ entrance. The dashed lines show theparticle distribution without the buncher. The capture
eﬃciencies ( ) are also indicated.

Fig. 3. Beam envelopes of all distributions of test particles
included in tracking simulation, where the number oftest particles is 2,000. The dotted lines indicate thebore radius of the drift tubes and the inner radius of
the beam pipes in the quadrupole magnets.

of the RFQ with a normalized transverse emittanceof 0.6π mm·mrad. The beam spreads to more than
±20 mm in the quadrupole magnets, for which we assume a magnetic ﬁeld gradient of 40 T/m in order to262

Table 2. Design parameters of DTLs.
Resonator
Frequency (MHz)Duty
Mass-to-charge ratio (m/q)
Input energy (keV/u)
Output energy (keV/u)
Length (= Diameter: m)
Height (m)Gap number
Gap voltage (kV)Gap length (mm)Drift tube aperture (a: mm)
Peak surface ﬁeld (MV/m)
Synchronous phase
Power (100% Q: kW)

DTL1
36.6
100 %
7
100
220
0.8
1.6
10
110
20
17.5
8.2
−25◦
6

DTL2
36.6
100 %
7
220
450
1.1
1.7
10
210
50
17.5
9.4
−25◦
12

DTL3
36.6
100 %
7
450
680
1.1
1.8
8
260
65
17.5
9.7
−25◦
17

References
1) K. Morita et al.: J. Phys. Soc. Jpn. 73, 1738 (2004).
2) T. Nakagawa et al.: RIKEN Accel. Prog. Rep. 39, 263(2006).
3) H. Fujisawa et al.: Nucl. Instrum. Methods Phys. Res.
A 345, 23 (1994).
4) O. Kamigaito et al.: Rev. Sci. Instrum. 76, 013306(2005).
5) N. Fukunishi et al.: RIKEN Accel. Prog. Rep. 39, 264(2006).

RIKEN Accel. Prog. Rep. 39 (2006)

New 18 GHz ECR ion source for new injector system
T. Nakagawa, M. Kidera, Y. Higurashi, O. Kamigaito, N. Fukunishi, H. Saitoh, A. Goto, and Y. Yano
As described in Ref. 1, the construction of a new
additional injector system for RRC has been proposedfor carrying out both SHI research and RIBF research
simultaneously in the RIKEN accelerator facility. The
new system, which consists of an ECR ion source, an
RFQ linac and a heavy ion linac, will be used to inject
intense beams of heavy ions to the ring cyclotron. The
ECR ion source will be constructed for producing intense beam of medium charge state of heavy ions, suchas Ar8+ , Kr13+ and Xe20+ .
Figure 1 shows a schematic drawing of the new
RIKEN 18 GHz ECR ion source. The new source hasan additional solenoid coil between two solenoid coils
as shown in Fig. 1. We found that the magnetic field
gradient at the resonance zone plays an essential rolein increasing the plasma density and electron temperature.2) The field gradient strongly depends on the minimum magnetic field strength (Bmin ) of the mirror field.
Using this coil arrangement, we can change Bmin without changing the maximum magnetic field (Bext andBinj ) independently to optimize the magnetic field gradient at the resonance zone. The maximum magnetic
field strength of the mirror field will be 1.4 T. Figure 2
shows the magnetic field configuration for Ar and Xe
ion beam production.
To confine plasma radially, we use a hexapole magnet which consists of 36 segments of permanent magnets.
The inner diameter and length of the plasma cham-Fig. 2. Magnetic field configuration for production of Ar8+
and Xe20+

ber are 78 and 300 mm, respectively. The magnetic
field strength at the surface of the inner wall of theplasma chamber is 1.25 T. To evacuate the plasmachamber to the order of 10−8 Torr, 150 and 300 l/s
turbo molecular pumps will be used.
To protect the hexapole magnet from demagnetization by a high temperature, the plasma chamber takes
double wall structure for flowing the cooling water.
The inner wall of plasma camber is covered by thinaluminum cylinder to supply the cold electrons to theplasma.3) The movable negatively biased disc will be
installed in the plasma chamber to tune plasma potential.4) These methods are very useful for increasing thebeam intensity of highly charged heavy ions from the
ECR ion source.
References

Fig. 1. Schematic drawing of new 18 GHz ECRIS.

1) O. Kamigaito et al.: RIKEN Accel. Prog. Rep. 39, 261(2006).
2) M. Imanaka et al.: Nucl. Instrum. Methods Phys. Res.
B 237, 647 (2005).
3) T. Nakagawa et al.: Jpn. J. Appl. Phys. 35, 4077 (1996).
4) S. Biri et al.: Nucl. Instrum. Methods Phys. Res. B 152,
386 (1999).

263

RIKEN Accel. Prog. Rep. 39 (2006)

Design studies on quadrupole magnets of new injector to RRC
N. Fukunishi, O. Kamigaito, H. Saito, and A. Goto
A new injector linac for the existing Riken Ring Cycloton (RRC) is proposed to realize the RIKEN RI
beam Factory project1) and further experiments on superheavy element search in RIKEN.2) Both projects
require the use of the existing RIKEN Linear Accelerator (RILAC) and are incompatible with each otherwithout the new injector system for the RRC. The
new injector linac is designed exclusively to produce
350 MeV/nucleon primary beams.3)
To obtain suﬃcient transverse focusing, the new injector linac requires two types of quadrupole magnets
with very high magnetic-ﬁeld gradients (0.4 T/cm).
The maximum beam size estimated in ion optical calculations is 45 mm. Hence, the pole-tip ﬁeld should beapproximately 1 T, which is nearly twice as large as
the maximum pole-tip ﬁeld of usual quadrupole magnets used in the beam transport system of the existing
facility. The present requirement is near the limit of
the conventional normal conducting magnet. The effective lengths were 6 and 10 cm for a short quadrupole
magnet (Qs ) and a long quadrupole magnet (Ql ), respectively. These quadrupole magnets will be used
as quadrupole doublets (Qs + Qs ) and quadrupole
triplets (Qs + Ql + Qs ). An additional requirement
for these magnets is compactness in the beam axis direction. The space allowed for coils is 4 cm for eachside in the beam direction. Because the existing facility does not use this type of compact and high ﬁeldgradient quadrupole magnet, we investigated whether
conventional normal conducting quadrupole magnets
fulﬁll the present requirements.
Our design studies started with the quadrupole magnet in the IH linac of the Institute for Nuclear Study,
Tokyo University, manufactured by Sumitomo Heavy
Industries, Ltd.4) The bore diameter was chosen to be
50 mm for both short and long quadupoles. We performed magnetic ﬁeld calculations to optimize magnet shapes to obtain better excitation properties. The
magnetic ﬁeld calculations were performed using the
TOSCA code.a) In the magnetic ﬁeld calculations,
we use the BH curve given in the TOSCA code asa default, the eﬀectiveness of which was suﬃciently
investigated by comparisons with magnets fabricatedin the RIBF project.5) Figure 1 shows a perspective
view of a short quadrupole magnet. The excitation
properties and eﬀective length of the quadrupole magnets are shown in Figs. 2 and 3, respectively. For thelong quadrupole magnet, a 0.41 T/cm ﬁeld gradient is
excited by 11900 ampere turns per pole, which corresponds to an overall current density of 6 A/mm2 .
On the other hand, the ﬁeld gradient of the shorta)264

Vector Field Ltd.

Fig. 1. Perspective view of short quadrupole.

Fig. 2. Excitation property of quadrupole magnets.

Fig. 3. Eﬀective length of quadrupole magnets.

quadrupole remains 92% of the requirement with an
excitation current of 14900 ampere turns per pole(=7.5 A/mm2 ). It is not eﬀective to increase excitation
current for well-saturated magnets and one method of
increasing ﬁeld gradient is reducing the bore diameterfrom 50 mm to 48 mm. In this case, it is preferable toTable 1. Cooling water conditions of the quadrapole magnets.

Number of turns/pole
Maximum current (A)Conductor size (mm)Current density (A/mm2 )Cooling water path
Coil length (m)Resistance (Ω)
Power consumption (kW)Pressure drop (MPa)
Velocity of cooling water (m/sec)
Water ﬂow rate (l/min)
Temperature rise of water (◦ C)

Qs
50
300
4 × 6 with 2 × 4 hole
19.23
2
Inner path Outer path
11.6
15.0
0.01280.0166
1.15
1.49
0.49
0.49
2.44
2.11
1.17
1.01
14.1
21.1

adopt a lozenge-shaped beam duct.
The cooling water conditions of the coil were also
estimated. The results are summarized in Table 1. The
maximum temperature rise of the cooling water is 26◦ C
with a pressure drop of 0.49 MPa, which is acceptablein our facility. In summary, we found the design ofnormal conducting quadrupole magnets, which fulﬁll
the requirements from the new injector system, eventhough we need additional optimization for the short
qudrupole magnet.

Ql
50
300
4 × 6 with 2 × 4 hole
19.23
2
Inner path Outer path
13.5
17.1
0.01490.0189
1.34
1.72
0.49
0.49
2.24
1.95
1.08
0.94
17.7
25.9

References
1) Y. Yano et al.: Proc. 17th Int. Conf. Cyclotrons andTheir Applications, Tokyo, 2004-10 (Particle Accelerator Society of Japan, 2005), p. 169.
2) K. Morita et al.: J. Phys. Soc. Jpn. 73, 1738 (2004).
3) O. Kamigaito et al.: RIKEN Accel. Prog. Rep. 39, 261(2006).
4) M. Tomizawa et al.: INS-Rep-1145 (1996).
5) N. Fukunishi et al.: RIKEN Accel. Prog. Rep. 34, 329(2001).

265

RIKEN Accel. Prog. Rep. 39 (2006)

Compact design of damped cavity using SiC HOM absorbers
J. Watanabe∗1 M. Izawa,∗2 T. Koseki, N. Nakamura,∗3 K. Nakayama,∗1 H. Sakai,∗3 K. Sato,∗1 H. Suzuki,∗1
and H. Takaki∗3
For electron storage rings with intense beam currents, the suppression of the coupled-bunch instability
due to higher-order modes (HOMs) in rf cavities is oneof the most important issues for stable operation. In
this paper, we present a compact design of the higherorder modes (HOMs) damped cavity using microwave
absorbers. The design is based on the cavity installedin the Photon Factory (PF) storage ring of KEK.1,2)
The PF-type cavity has a large-diameter beam duct
made of a silicon-carbide (SiC) microwave absorber.
The HOMs that have a frequency higher than the cutoﬀ frequency of the beam duct are guided out of thecavity and dissipated by the absorber. The PF-type
cavity has also been adopted at the New SUBARU
ring of the University of Hyogo and at the SAGA Light
Source in Tosu city, Saga prefecture.3)
The PF-type cavity has a total length of more than
1.3 m in the longitudinal direction.2) The length is relatively large and a shorter design is preferable to savethe length of the cavity section in a storage ring andto provide space for installing an insertion device in astraight section together with the cavities. Recently,
we have proposed a shorter design of the PF-type
damped cavity. In the shorter design, a pair of cavities can be installed in a 2 m straight space as shownin Fig. 1, a cross-sectional view of a half of the pair ofcavities.
The shorter design was obtained by eliminating thetapered duct between cavities and adjusting the lengthand position of the SiC duct. In addition, the diameter of the beam duct is reduced from 140 mm, the sizeof the original PF-type cavity, to 125 mm. As a result,the shunt impedance of the accelerating mode becomes

8.2 MΩ, which is 6% larger than that of the original
PF-type cavity. However, reducing the beam-duct diameter increases the HOM impedances and the number of trapped HOMs, which are not damped by the
SiC duct because their frequencies are below the cutoﬀ frequency of the beam duct. In order to damp thetrapped modes, three HOM dampers with rod-shaped
coupling antennas4,5) are employed.
Figure 2 shows a 3D view of the cavity with thee
HOM dampers. Two dampers are attached to the longitudinal center position of the cavity in horizontal andvertical directions. In contrast, the third HOM damperis placed at an oﬀ-centered position to couple theTM012- and TM022-like modes. Figure 3 shows theelectric ﬁeld of the TM022-like mode and the positionof the oﬀ-centered damper. The oﬀ-centered damper
can couple the electric ﬁeld of the TM012- and TM022like modes eﬀectively and reduce their impedances.
The new design presented in this paper has been
adopted in a 3.0-GeV storage ring of the Australian
Synchrotron Project (ASP), which is under construction in Melbourne.6) The main parameters of the rf

Fig. 2. Schematic drawing of rf cavity with three HOM
dampers.

Fig. 1. Cross-sectional view of shorter design of damped
cavity.
∗1
∗2
∗3

266

Toshiba Corporation
High Energy Accelerator Research Organization (KEK)
Institute for Solid State Physics, University of Tokyo

Fig. 3. Field distribution of TM022-like mode.

cavity for the ASP ring are listed in Table 1.
Figure 4 shows the manufactured high-power models of the cavity for the ASP ring. Photographs of theon-centered and oﬀ-centered HOM dampers are shownin Figs. 5 and 6, respectively. The HOM dampers havea rod-shaped antenna followed by a coxial waveguide.
Table 1. Main parameters of rf cavity for ASP ring.
Frequency [MHz]Number of cavities
Rf voltage/cavity [MV]
Coupling constant
Shunt impedance [MΩ]
Unloaded Q
Nominal beam current [mA]

499.654
4
0.75
1.7
8.2
> 30000
200

Fig. 4. Photograph of cavities for ASP ring.

Fig. 6. Photograph of oﬀ-centered damper.

A cylindrical SiC piece made of the same material as
the absorber at the beam duct is attached to the end of
the coaxial waveguide and absorbs the extracted HOM
power. The design of the HOM dampers is based on
the structure described in the Ref. 5, but modiﬁed so
as to dissipate higher rf power, which is required for
the ASP ring. We have measured rf characteristicsof the cavity with the HOM dampers at a low power
level. It is conﬁrmed that the Q-values of all trapped
HOMs except TM011V- and TM011H-like modes aredamped below the critical values so as not to induce
the coupled-bunch instabilities in the ASP ring. For
TM011H- and TM011V-like modes, which do not couple the rod-shaped antenna of the HOM dampers, theirfrequencies are detuned well by the tuner block attached to the on-centered damper so as not to coincidewith the coupled-bunch mode frequencies.
Now, we are carrying out high-power conditioningof the cavities and HOM dampers, together with theother components such as input couplers and movabletuners. They will then be sent to Melbourne afterwards.
References

Fig. 5. Photograph of on-centered damper.

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. Tomimasu et al.: Proc. PAC2003 (2003), p. 902.
4) T. Koseki et al.: Proc. EPAC1998 (1998), p. 1776.
5) T. Koseki et al.: Nucl. Instrum. Methods Phys. Res. A
467/468, 91 (2001).
6) J. Watanabe et al.: Proc. PAC2005 (2005), p. 3076.

267

RIKEN Accel. Prog. Rep. 39 (2006)

Highly charged ion generation using Nd-glass laser
S. Kondrashev,∗1 T. Kanesue,∗2 M. Okamura, and K. Sakakibara∗3
At present, the laser ion source (LIS) is the mostintense source to ﬁll synchrotron rings in a single turninjection mode using highly charged ions.1) One of themost promising methods of intense highly charged ion
beam extraction and acceleration is the direct plasma
injection scheme (DPIS), proposed in RIKEN a few
years ago.2) About 35 mA of C4+ ions and 17 mA of
C6+ ions were accelerated by RFQ up to 100 keV/uusing DPIS.3) As the next step, DPIS will be tested toaccelerate intense highly charged ion beams of heavier
elements.
Laser-produced plasma parameters (charge state
distribution, currents and ion pulse durations) have tobe speciﬁed before conducting acceleration tests. A
3 J/30 ns Nd-glass laser (B.M. Industries model 511
DNS13 laser courtesy of Center for Nuclear Study,
Tokyo University) was used to generate highly charged
ions of diﬀerent elements from 12 C to 181 Ta. Lenses
with focal lengths of 100 mm and 300 mm were used
to focus laser beam onto a target surface at an incident angle 30 degrees. Taking into account 0.5 m
as a typical disergence for such type of lasers, focal
spot size can be estimated to be 50 µm and 150 µm
for these cases and the maximum laser power densities
reach 1012 W/cm2 and 1011 W/cm2 at the target surface respectisely. A Faraday cup (FC) for measuring
ion current and an electrostatic ion analyzer (EIA) for
measuring charge state distribution were placed at distances of 2.4 m and 3.7 m from the target normal to thetarget surface respectively. The detailed description of
the experimental setup and focal position search procedure can be found in Refs. 4 and 5. Special attention
was paid to carry out correct measurements: the linear
range of secondary electron multiplier (SEM) voltage
was found and used for all measurements; the widthsof the ﬁrst and second slits of the EIA were chosen
to be 100 µm and 10 mm respectively to minimize thepossible inﬂuence of space-charge eﬀects inside the analyzer.
Having an entire set of FC and EIA data, ion currents, pulse durations, energy ranges and numbers ofions with diﬀerent charge states were speciﬁed for 12 C,
27
Al, 48 Ti, 56 Fe, 74 Ge, 93 Nb and 181 Ta targets fortwo diﬀerent laser power densities: 1012 W/cm2 and1011 W/cm2 (except for the 48 Ti, 56 Fe and 74 Ge targets). The independence of secondary electron emission coeﬃcient on the energy and charge state of registered ions was supposed. Ion charge states with the
∗1
∗2
∗3

268

Institute of Theoretical and Experimental Physics, Russia
Department of Energy Science and Engineering, Kyushu
University
Department of Energy Sciences, Tokyo Institute of Technology

highest current (for 1012 W/cm2 - 1, for 1011 W/cm2- 3) and maximal registered ion charge states (for1012 W/cm2 - 2, for 1011 W/cm2 - 4) are summarizedin Table 1 for all elements together with corresponding ionization potentials6) (in eV). From Table 1, one
can clearly separate two groups of elements: highly
charged ions with ionization potentials in the range
500–1000 eV were registered for all elements between
12
C and 56 Fe; at the same time, ions with about-oneorder-less ionization potentials were registered for elements between 74 Ge and 181 Ta.
The most probable reason for such a big diﬀerence
is recombination losses of highly charged ions duringlaser-produced plasma expansion into vacuum. Special
measurements were performed to verify recombination
losses in the case of the Ta target. FC was placed atthree diﬀerent distances (L) from the target: 32.5 cm(deﬁned by the geometry and possible breakdown of
the FC suppressor), 142 cm and 242 cm. Time structures of FC currents recorded at these distances fromthe target were scaled to one distance according to theL−3 law7) and no diﬀerence among all three curves wasfound. This means that there are no recombination
losses of ions in Ta plasma at distances longer than
32.5 cm from the target and recombination processes
should take place at shorter distances. Another interesting result obtained is the existence of two diﬀerent
groups of ions for all elements and laser power densities used in experiments: the faster group has a very
weak dependence of energy on ion charge state, and theslower group always follows the low Ez = 0.5 keV·z(where z is the charge state and Ez is the energy ofions with charge state z corresponding to maximum
ion current) with very high accuracy.
Table 1. Ion charge states with highest current and maximal registered ion charge states for diﬀerent elementsof periodic table.

References
1) S. Kondrashev et al.: Proc. EPAC2004 (2004), p. 1402.
2) M. Okamura et al.: Laser Part. Beams 20, 451 (2002).
3) H. Kashiwagi et al.: Rev. Sci. Instrum. 75, 1569 (2004).
4) K. Sakakibara et al.: RIKEN Accel. Prog. Rep. 39, 105(2006).
5) T. Kanesue et al.: RIKEN Accel. Prog. Rep. 39, 106(2006).
6) Th. A. Carlson et al.: At. Data, 2, 63 (1970).
7) B. Sharkov and S. Kondrashev: Proc. EPAC1996(1996), p. 1550.

RIKEN Accel. Prog. Rep. 39 (2006)

Carbon beam using DPIS†M. Okamura, S. Kondrashev,∗1 K. Sakakibara,∗2 and T. Kanesue∗3
Since 2004, we have been studying carbon beam
acceleration using the direct plasma injection scheme(DPIS). A newly designed 100 MHz RFQ was fabricated at the Institute for Applied Physics, Goethe University, Frankfurt. The deposited energy on a carbon
target and the pulse width of the CO2 laser were measured to be 1.2 J and 85 ns (FWMS), respectively. The
charge state distribution of the laser carbon plasma
was examined before acceleration. In the ﬁrst peak,excluding the tail that appears after 2 µs, the maincontent was C4+ (50%) and the rest of the ions consisted of C5+ (35%) and C3+ (15%).
The carbon target was placed at a position 320 mm
upstream from the beginning of the vanes. A small
stage for optics that included the target, a concave focusing lens and a plasma guide pipe, which directly
faced the vanes, was isolated and surrounded completely by a grounded vacuum box. Up to 100 kV could
be applied to the stage and the applied voltage was set
to 60 kV for C4+ beam acceleration. An electrostatic
analyzer was installed after the RFQ. Its bending radius was 100 mm and the distance between positive
and negative electrodes was 5 mm. Two Faraday cups
were placed before and after the analyzer.
The accelerated beam was analyzed, and acquired
separated beam currents are shown in Fig. 1. To obtain3+ 4+,
and 5+ beam currents, voltages of 20 kV, 15 kV
and 12 kV, respectively, were applied to the electrodes.
Since all the ions were extracted with the stage voltageof 60 kV, all the unaccelerated ions can be bent by the
analyzer with at an applied voltage of 3 kV. Therefore, it was diﬃcult to investigate the contents of theunaccelerated beam.
The electrostatic analyzer only has a small opening,which corresponds to about 2.5% of the momentum
acceptance instead of 10% of the energy spreads of thebeam extracted from the RFQ. This means that theanalyzed current only represented a small portion of
the beam that was sliced out from 2.5% of the momentum window. Of course, the beam being accelerated was captured by a longitudinal RF bucket and its
momentum distribution was caused by a synchrotron
oscillation in the RFQ. Then the obtained current
should be aﬀected by the distribution pattern in thebucket. Also, in comparison with the beam size after
the RFQ, the opening could only sample a small solid
angle. The beam divergence after the RFQ of eachcharge state depends on space charge forces and theeﬀects should not be identical for all the charge states.
†
∗1
∗2
∗3

Condensed from the article in ICIS05 proceedings
Institute for Theoretical and Experimental Physics, Russia
Tokyo Institute of Technology
Kyusyu University

Fig. 1. Analyzed beam pulse.

Note that the information speciﬁed in Fig. 1 provides
us only a rough quantitative analysis.
The C4+ and 5+ beams were shown from 1.9 µs to
3.8 µs. The C3+ beam had a longer pulse period, whichlasted up to 5.6 µs. When we applied the integrated
areas of each charge state indicated in Fig. 1 to thetotal accelerated current measured using the Faraday
cup just after the RFQ, the C4+ occupied more than
60% of the beam which corresponded to 6.3 × 1010
particles.
Since the injection bias voltage was 60 kV, the C3+
beam only has a kinetic energy of 180 keV instead ofthe designed value of 240 keV. Even in this condition,some portions of the injected C3+ beam were captured
and were accelerated up to 1.2 MeV.
The tail of the current, which started from 4 µs,
mainly consisted of the unaccelerated beams that wereassumed to originate from C1+ , 2+ and 3+ . Some particles of C4+ and 5+ that were longitudinally lost fromthe acceleration RF buckets might be contained in thetail.
The unaccelerated beam still has a high intensity.
This is evidence that an intense beam from the DPIS
can be captured transversely through the entire lengthof the cavity by the RFQ focusing force. If we havea long unmodulated section in the beginning of thevanes, pulse width can be expanded due to the momentum spread and space charge repulsion force. Using anadequate beam injection energy, the pulse duration of
the extracted beam might be controlled without signiﬁcant beam loss.
Reference
1) M. Okamura, T. Katayama, R. A. Jameson, T.
Takeuchi, T. Hattori, and H. Kashiwagi: Laser Part.
Beams 20, 451 (2002).

269

RIKEN Accel. Prog. Rep. 39 (2006)

Routine work for radiation safety in ring cyclotron facility
Y. Uwamino, S. Fujita, H. Sakamoto, R. Hirunuma, H. Mukai,∗1 A. Horigome,∗2 T. Yamaki, and N. Yukawa
We report here the residual radioactivity and leakage
radiation level at the RIKEN Ring Cyclotron (RRC)
facility.
Residual radioactivity in the facility was measured
at various locations using AE133V ionization-chamber
gamma-ray survey meters of Applied Engineering Inc.
The scheduled overhaul started immediately after theexperiment that was carried out with an 56 Fe beamof 83 MeV/nucleon in the E2 experimental vault from
July 30 to August 2, 2005. The dose rates at the deﬂectors of the injector AVF cyclotron and RRC were
found to be 2 mSv/h and 20 mSv/h on August 9 and
10, respectively.
In addition to the above measurement, dose rates
inside the injector AVF cyclotron were measured on
October 14, 2004. The dose rates were 3.6 mSv/h at
the deﬂector and 0.46 mSv/h at the magnetic channel.
A minor rearrangement was carried out with the deﬂector after the measurement.
During the period from October 1, 2004 to September 30, 2005, the dose rates were measured along thebeam lines after almost every experiment. Spots a–x,
marked by bullets in Fig. 1, are the places where thedose rates exceeded 30 µSv/h. Table 1 summarizes theobserved dose rates and gives the dates on which themeasurements were performed. The maximum dose
rate was found to be 850 µSv/h at the beam dump
in the E3 experimental vault denoted by u in Fig. 1.
Whenever we observed a high dose rate, we roped-oﬀ
the area and posted a warning sign indicating that it
was dangerous to remain for a long time in that place.
We paid particular attention to measuring the leakage radiations in and around the RRC facility when a
63-MeV/nucleon 40 Ar beam of 750 pnA intensity was
stopped by a Faraday cup, FC-D50, in the beam distribution corridor, without any local shield. Aloka TPS451BS neutron rem counters and AE133V gamma-ray
survey meters were used. The measured results areshown in Table 2. The leakage was found to be small
compared with the legal limits, which are 25 µSv/h for
A–D in the radiation controlled area and 2.6 µSv/h for
E at the boundary of the radiation controlled area.
We also continuously monitored the leakage radiation from the RRC facility using neutron and gammaray active area monitors and passive monitors withthermoluminescence dosimeter (TLD). The passive

Fig. 1. Layout of RIKEN Ring Cyclotron facility as of 2005. Measured locations of residual radioactivity
along the beam lines are indicated by bullets a–x. Locations of leakage neutron and gamma-ray
measurements when an 40 Ar beam was stopped at FC-D50 are indicated by open triangles A to D
and open circle E. Open squares F and G are the positions of TLD-rem measurements.
∗1∗2

Japan Environment Research Corporation
Tokyo University of Science271

Table 1. Summary of dose rates measured along the beam lines with ionization-chamber survey meters.
Detection points a–x indicate measured locations shown in Fig. 1.

Table 2. Measured dose rates in and around RRC facility when 63-MeV/nucleon 750-pnA 40 Ar beam
was stopped by Faraday cup, FC-D50, without any local shield. Measured points are shown in Fig. 1.

neutron dosimeter was developed by us, and it measures the neutron eﬀective dose.
The leakage radiations were below the detection
limit of the environmental area monitors placed near
the site boundary. We evaluated the radiation levelat the boundary of the radiation controlled area measured using an area monitor installed in the computerroom on the ground ﬂoor immediately above a bending magnet that guided the beams from the RRC vault
to the distribution corridor, and it was approximately

272

9.6 µSv/y, which was much lower than the allowable
dose limit (1 mSv/y).
The results obtained with the passive dosimeters
placed around the radiation controlled area were below the detection limit, which was approximately
0.2 mSv/y, and the results obtained with them placedin the RRC facility at points F and G in Fig. 1 were
3.5 mSv/y and 1.6 mSv/y, respectively. The legal dose
limits for these positions were 50 mSv/y.

VI. LIST OF PUBLICATIONS
1. Accelerator
physics

development

andaccelerator

V. Banerjee, A. Chakrabarti, A. Bandyopadhyay, T. K.
Bhaumik, M. Mondal, T. K. Chakraborty, H. Pande,
O. Kamigaito, A. Goto, and Y. Yano: “The designof a radio frequency quadrupole LINAC for the RIB
project at VECC Kolkata”, Pramana J. Phys. 59,
No. 6, pp. 957–962 (2002).
P. Strasser, K. Nagamine, T. Matsuzaki, K. Ishida, Y.
Matsuda, K. Itahashi, and M. Iwasaki: “Progress inmuonic atom spectroscopy with RI beams”, Nucl.
Phys. A 746, 621c–624c (2004).
Y. Nagashima, F. Saito, Y. Itoh, A. Goto, and T.
Hyodo: “Measurement of Cu K-shell and Ag L-shellionization cross sections by low-energy positron impact”, Phys. Rev. Lett. 92, No. 22, pp. 223201-1–
223201-4 (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”, Proccdings of the 1st Annual Meeting of Particle Accelerator Society of Japan/The
29th Linear Accelerator Meeting in Japan, Funabashi, 2004–8, Funabashi, pp. 224–226 (2004).
A. Goto: “Cyclotrons 2004”, J. Particle Accelerator
Society of Japan 2, No. 1, pp. 58–62 (2005).
M. Kawaguchi, K. Ushida, S. Kashiwagi, R. Kuroda,
T. Kuribayashi, M. Kobayashi, Y. Hama, and M.
Washio: “Development of compact picosecond pulse
radiolysis system”, Nucl. Instrum. Methods Phys.
Res. B 236, 425–431 (2005).
G. Bonomi, M. Amoretti, P. Bowe, C. Canali, C.
Carraro, C. Cesar, M. Charlton, M. Doser, A.
Fontana, M. Fujiwara, R. Funakoshi, P. Genova, J.
Hangst, R. Hayano, L. Jorgensen, A. Kellerbauer,
V. Lagomarsino, R. Landua, E. Rizzini, M. Macri,
N. Madsen, G. Manuzio, P. Montagna, D. Mitchard,
A. Rotondi, G. Testera, A. Variola, L. Venturelli, Y.
Yamazaki, D. van der Werf, and N. Zurlo: “Antihydrogen production mechanisms in ATHENA”, Nucl.
Phys. A 752, 97c–100c (2005).
R. Taki, H. Okamura, N. Fukunishi, H. Ryuto, N.
Sakamoto, K. Sekiguchi, and A. Goto: “Response ofa germanium detector to energetic heavy ions”, Nuclear Instruments and Methods in Physics Research
A 545, 269–272 (2005).
M. Komiyama, M. Kase, and M. Fujimaki: “Beam interlock system at RIKEN RI beam factory”, Proccdings of the 2nd Annual Meeting of Particle Accelerator Society of Japan/The 30th Linear Accelerator
Meeting in Japan, Tosu, 2005–7, Particle Accelerator Society of Japan, Tosu, pp. 615–617 (2005).
H. Ryuto, T. Abe, N. Fukunishi, M. Kase, and Y.
Yano: “Heavy-ion beam irradiation system for bi-

ological samples in RIKEN”, Proceedings of International Symposium on Novel Techniques in NanoBiology 2005 (ISNB05), (Biology Research Centerof Industrial Accelerators and others), Naju, Korea,
2005–4, BRCIA, Naju, pp. 24–32 (2005).
O. Kamigaito, M. Kase, N. Sakamoto, Y. Miyazawa,
E. Ikezawa, N. Fukunishi, S. Kohara, M. Fujimaki,
M. Hemmi, T. Chiba, Y. Chiba, H. Ryuto, A. Goto,
and Y. Yano: “Construction of a booster linac for
the RIKEN heavy-ion linac”, Rev. Sci. Instrum. 76,
013306-1–013306-11 (2005).
T. Tominaka: “Calculations using the helical ﬁlamentary structure for current distributions of twisted superconducting multiﬁlamentary composites”, Supercond. Sci. Technol. 18, 634–643 (2005).
T. Tominaka: “Two-dimensional magnetic ﬁelds of pieshaped conductors”, Supercond. Sci. Technol. 18,
881–887 (2005).
H. Imao, N. Kawamura, K. Ishida, T. Matsuzaki, Y.
Matsuda, A. Toyoda, and K. Nagamine: “Dependence of muon-catalyzed d-d fusion on the orthopara ratio in solid and liquid deuterium”, Phys. Lett.
B 632, 192–196 (2006).

2.

Nuclear physics and nuclear instrumentation

D. Kharzeev, A. Krasnitz, and R. Venugopalan:“Anomalous chirality ﬂuctuations in the initial stageof heavy ion collisions and parity odd bubbles”,
Phys. Lett. B 545, 298–306 (2002).
A. Yoshimi, K. Asahi, and S. Emori: “Nuclear spinmaser and atomic electric dipole moment of 129Xe”,
Czech. J. Phys. 53, No. Suppl. B, pp. B227–B233(2003).
D. Kaji, K. Morita, K. Morimoto, Y. Zhao, A. Yoneda,
T. Suda, A. Yoshida, H. Kudo, K. Katori, and I.
Tanihata: “Status of heavy element synthesis in
RIKEN”, J. Radioanal. Nucl. Chem. 255, No. 1, pp.
77–80 (2003).
M. Golovkov, Y. T. Oganessian, D. Bogdanov, A.
Fomichev, A. Rodin, S. Sidorchuk, R. Slepnev,
S. Stepantsov, G. Ter-Akopian, R. Wolski, V.
Gorshkov, M. Chelnokov, M. Itkis, E. Kozulin,
A. Bogatchev, N. Kondratiev, I. Korzyukov, A.
Yukhimchuk, V. Perevozchikov, Y. Vinogradov,
S. Grishechkin, A. Demin, S. Zlatoustovskiy, A.
Kuryakin, S. Fil’chagin, R. Il’kayev, F. Hanappe,
T. Materna, L. Stuttge, A. Ninane, A. A.
Korsheninnikov, E. Nikolski, I. Tanihata, P.
Roussel-Chomaz, W. Mittig, N. Alamanos, V.
Lapoux, E. Pollacco, and L. Nalpas: “Evidences forresonance states in 5 H”, Phys. Lett. B 566, 70–75(2003).
T. Blum, P. Chen, N. Christ, C. Cristian, C. Dawson,
G. Fleming, R. D. Mawhinney, S. Ohta, G. Siegert,

273

A. Soni, P. Vranas, M. Wingate, L. Wu, and Y.
Zhestkov: “Kaon Matrix Elements and CP Violationfrom Quenched Lattice QCD: The 3-Flavor Case”,
Phys. Rev. D 68, 114506-1–114506-70 (2003).
T. Katayama, T. Suda, and I. Tanihata: “Status of
MUSES project and electron RI collider at RIKEN”,
Phys. Scr. T 104, 129–143 (2003).
Y. Motizuki and S. Kumagai: “Radioactivity of the
Key Isotope 44 Ti in SN 1987A”, AIP Conf. Proc.
704, 369–374 (2004).
A. Ozawa: “Measurements of reaction cross-sections
and determination of nucleon matter density distributions”, Horizons World Phys. 244, 301–321(2004).
T. Asano, T. Wada, M. Ohta, T. Ichikawa, S. Yamaji,and H. Nakahara: “Dynamical calculation of multimodal nuclear ﬁssion of fermium nuclei”, J. Nucl.
Radiochem. Sci. 5, 1–5 (2004).
K. Morita, K. Morimoto, D. Kaji, S. Goto, H. Haba,
E. Ideguchi, R. Kanungo, K. Katori, H. Koura, H.
Kudo, T. Ohnishi, A. Ozawa, J. Peter, T. Suda,
K. Sueki, I. Tanihata, F. Tokanai, H. Xu, A. V.
Yeremin, A. Yoneda, A. Yoshida, Y. L. Zhao, andT. Zheng: “Status of heavy element research using
GARIS at RIKEN”, Nucl. Phys. A 734, 101–108(2004).
A. Ozawa: “Recent experiments for interaction andreaction cross-sections”, Nucl. Phys. A 734, 315–
318 (2004).
D. Kameda, K. Asahi, H. Ueno, A. Yoshimi, H.
Watanabe, H. Miyoshi, K. Shimada, J. Murata,
Y. Kobayashi, G. Kato, S. Emori, W. Sato, andH. Ogawa: “Recent result from the nuclear moment measurements using a spin polarized radioactive beam”, Nucl. Phys. A 734, 481–484 (2004).
S. Sugimoto, K. Ikeda, and H. Toki: “Charge- andparity-projected Hartree-Fock study with the tensor
force of light nuclei”, Nucl. Phys. A 738, 240–244(2004).
A. Yoshimi, H. Ueno, W. Sato, H. Watanabe, Y.
Kobayashi, J. Murata, H. Miyoshi, K. Shimada, andK. Asahi: “Study on the transient ﬁeld at very highvelocities for the g-factor measurement of excitedstates in unstable nuclei”, Nucl. Phys. A 738, 519–
522 (2004).
S. Sugimoto, K. Ikeda, and H. Toki: “Charge- andparity-projected Hartree-Fock method for the strong
tensor correlation and its application to the alphaparticle”, Nucl. Phys. A 740, 77–94 (2004).
M. Wakasugi, T. Suda, and Y. Yano: “A new
method for electron-scattering experiments using aself-conﬁning radioactive ion target in an electron
storage ring”, Nuclear Instruments and Methods inPhysics Research A 532, 216–223 (2004).
S. Nishimura, Y. Nishi, M. Kurata-Nishimura, I.
Tanihata, M. A. Famiano, M. E. Howard, D.
Reitzner, E. E. Smith, and R. N. Boyd: “Half-

274

life measurement of neutron-rich nuclei and future
at RIBF”, Origin Matter and Evolution of Galaxies 2003: Proceedings of International Symposiumon Origin Matter and Evolution of Galaxies 2003,(CNS, RIKEN, and others), Wako, 2003–12, World
Scientiﬁc, Hackensack, pp. 304–315 (2004).
Z. Elekes, Z. Dombradi, A. Krasznahorkay, H. Baba,
M. Csatlos, L. Csige, N. Fukuda, Z. Fulop, Z. Gacsi,
J. Gulyas, N. Iwasa, N. Kinugawa, S. Kubono, M.
Kurokawa, X. Liu, S. Michimasa, T. Minemura, T.
Motobayashi, A. Ozawa, A. Saito, S. Shimoura, S.
Takeuchi, I. Tanihata, P. Thirolf, Y. Yanagisawa,
and K. Yoshida: “Decoupling of valence neutrons
from the core in 16 C”, Phys. Lett. B 586, 34–40(2004).
T. Suzuki, H. Bhang, G. Franklin, K. Gomikawa, R.
Hayano, T. Hayashi, K. Ishikawa, S. Ishimoto, K.
Itahashi, M. Iwasaki, T. Katayama, Y. Kondo, Y.
Matsuda, T. Nakamura, S. Okada, H. Outa, B.
Quinn, M. Sato, M. Shindo, H. So, P. Strasser,
T. Sugimoto, K. Suzuki, S. Suzuki, D. Tomono,
A. M. Vinodkumar, E. Widmann, T. Yamazaki, andT. Yoneyama: “Discovery of a strange tribaryon
S0 (3115) in 4 He (stopped K − , p) reaction”, Phys.
Lett. B 597, 263–269 (2004).
Z. Elekes, Z. Dombradi, A. Saito, N. Aoi, H. Baba,
K. Demichi, Z. Fulop, J. D. Gibelin, T. Gomi, H.
Hasegawa, N. Imai, M. Ishihara, H. Iwasaki, S.
Kanno, S. Kawai, T. Kishida, T. Kubo, K. Kurita,
Y. Matsuyama, S. Michimasa, T. Minemura, T.
Motobayashi, M. Notani, T. Ohnishi, H. Ong, S.
Ota, A. Ozawa, H. Sakai, H. Sakurai, S. Shimoura,
E. Takeshita, S. Takeuchi, M. Tamaki, Y. Togano,
K. Yamada, Y. Yanagisawa, and K. Yoneda: “Bound
excited states in 27 F”, Phys. Lett. B 599, 17–22(2004).
D. Fang, T. Yamaguchi, T. Zheng, A. Ozawa, M.
Chiba, R. Kanungo, T. Kato, K. Morimoto, T.
Ohnishi, T. Suda, Y. Yamaguchi, A. Yoshida, K.
Yoshida, and I. Tanihata: “One-neutron halo structure in 15 C”, Phys. Rev. C 69, 034613-1–034613-6(2004).
K. Sekiguchi, H. Sakai, H. Witala, K. Ermisch,
W. Gloeckle, J. Golack, M. Hatano, H. Kamada,N. Kalantar-Nayestanaki, H. Kato, Y. Maeda, J.
Nishikawa, N. Andreas, T. Ohnishi, H. Okamura, T.
Saito, N. Sakamoto, S. Sakoda, Y. Sato, K. Suda,
A. Tamii, N. Uchigashima, T. Uesaka, T. Wakasa,
and K. Yako: “Polarization transfer measurement
 p)2 H elastic scattering at 135 MeV/nucleon
for 1 H(d,and three-nucleon force eﬀects”, Phys. Rev. C 70,
014001-1–014001-17 (2004).
Y. Yamaguchi, C. Wu, T. Suzuki, A. Ozawa, D. Fang,
M. Fukuda, N. Iwasa, T. Izumikawa, H. Jeppesen, R.
Kanungo, R. Koyama, T. Ohnishi, T. Ohtsubo, W.
Shinozaki, T. Suda, M. Takahashhi, and I. Tanihata:“Density distribution of 17 B from a reaction cross-section measurement”, Phys. Rev. C 70, 054320-1–
054320-6 (2004).
N. Imai, H. Ong, N. Aoi, H. Sakurai, K. Demichi,
H. Kawasaki, H. Baba, Z. Dombradi, Z. Elekes,
N. Fukuda, Z. Fulop, A. Gelberg, T. Gomi, H.
Hasegawa, K. Ishikawa, H. Iwasaki, E. Kaneko,
S. Kanno, T. Kishida, Y. Kondo, T. Kubo, K.
Kurita, S. Michimasa, T. Minemura, M. Miura, T.
Motobayashi, T. Nakamura, M. Notani, T. Onishi,
A. Saito, S. Shimoura, T. Sugimoto, M. Suzuki, E.
Takeshita, S. Takeuchi, M. Tamaki, K. Yamada, K.
Yoneda, H. Watanabe, and M. Ishihara: “Anoma+
16
C”,
lously hindered E2 strength B(E2; 2+
1 →0 ) in
Phys. Rev. Lett. 92, 062501-1–02501-4 (2004).
D. Cortina-Gil, J. Fernandez-Vazquez, T. Aumann, T.
Baumann, J. Benlliure, M. J. Borge, L. V. Chulkov,
U. DattaPramanik, C. Forssen, L. M. Fraile, H.
Geissel, J. Gerl, F. Hammache, K. Itahashi, R.
Janik, B. Jonson, S. Mandal, K. Markenroth, M.
Meister, M. Mocko, G. Munzenberg, T. Ohtsubo,
A. Ozawa, Y. Prezado, V. Privora, K. Riisager,
H. Scheit, R. Schneider, G. Schreider, H. Simon,
B. Sitar, A. Stolz, P. Strmen, K. Summerer, I.
Szarka, and H. Weick: “Shell structure of the neardripline nucleus 23O”, Phys. Rev. Lett. 93, No. 6,
pp. 062501-1–062501-4 (2004).
T. Matsuura, T. Hatsuda, K. Iida, and G. Baym:“Thermal phase transition of dense QCD”, Proceedings of International Conference on Color Conﬁnement and Hadrons in Quantum Chromodynamics:
Conﬁnement 2003, Wako, 2003–7, World Scientiﬁc,
Singapore, pp. 346–357 (2004).
Y. Motizuki, H. Madokoro, and T. Shimizu: “Corecollapse supernovae induced by anisotropic neutrino radiation”, Proceedings of International Confrence in Honour of the 60th Birthday of Marcel
Arnould: The Future Astronuclear Physics From
Microscopic Puzzles to Macroscopic Nightmares,(University Libre de Bruxelles), Brussels, Bergium,
2003–8, A. Jorissen and others, EDP Sciences, Les
Ulis, pp. 163–171 (2004).
Y. Motizuki, T. Tachibana, S. Goriely, and H. Koura:“Required precision of mass and half-life measurements for r-process nuclei planned at futureRadioactive-Ion-Beam facilities”, Proceedings of International Confrence in Honour of the 60th Birthday of Marcel Arnould: The Future Astronuclear
Physics From Microscopic Puzzles to Macroscopic
Nightmares, (University Libre de Bruxelles), Brussels, Bergium, 2003–8, A. Jorissen and others, EDP
Sciences, Les Ulis, pp. 227–234 (2004).
K. Sekiguchi, H. Sakai, H. Okamura, A. Tamii, T.
Uesaka, K. Suda, N. Sakamoto, T. Wakasa, Y. Sato,
T. Ohnishi, K. Yako, S. Sakoda, H. Kato, Y. Maeda,
M. Hatano, J. Nishikawa, T. Saito, N. Uchigashima,
N. N. Kalantar, and K. Ermisch: “Measurement of
Nucleon-Deuteron Scattering as a Good Probe to

Study Three Nucleon Forces”, Proceedings of theInternational Symposium on A New Era of Nuclear
Structure Physics (NENS03), (Niigata University),
Kurokawa-mura, Niigata Pref., 2003–11, World Scientiﬁc, Singapore, pp. 17–21 (2004).
D. Kameda, K. Asahi, H. Miyoshi, K. Shimada, G.
Kato, S. Emori, G. Kijima, H. Ueno, A. Yoshimi, H.
Watanabe, T. Haseyama, Y. Kobayashi, J. Murata,
W. Sato, and H. Ogawa: “g-factor measurementof 19 N”, Proceedings of the International Symposium on A New Era of Nuclear Structure Physics(NENS03), (Niigata University), Kurokawa-mura,
Niigata Pref., 2003–11, World Scientiﬁc, Singapore,pp. 231–235 (2004).
K. Iida, K. Oyamatsu, and B. A. Sarhan: “Deducing the density dependence of the symmetry energy from unstable nuclei”, Proceedings of the International Symposium on A New Era of Nuclear
Structure Physics (NENS03), (Niigata University),
Kurokawa-mura, Niigata Pref., 2003–11, World Scientiﬁc, Singapore, pp. 342–343 (2004).
H. Miyoshi, K. Shimada, K. Asahi, D. Kameda, K.
Sakai, S. Emori, G. Kato, H. Ueno, A. Yoshimi,
H. Watanabe, Y. Kobayashi, J. Murata, W. Sato,
H. Ogawa, and W. D. Schmidt-Ott: “Low-energyof polarized RI atomic beam”, Proceedings of theInternational Symposium on A New Era of Nuclear
Structure Physics (NENS03), (Niigata University),
Kurokawa-mura, Niigata Pref., 2003–11, World Scientiﬁc, Singapore, pp. 357–358 (2004).
K. Shimada, K. Asahi, H. Miyoshi, D. Kameda, K.
Sakai, S. Emori, G. Kato, G. Kijima, M. Tsukui, A.
Yoshimi, H. Ueno, Y. Kobayashi, H. Watanabe, T.
Haseyama, and J. Murata: “Developement of an extraction chamber for the RI atomic beam resonancemethod”, Proceedings of the International Symposium on A New Era of Nuclear Structure Physics(NENS03), (Niigata University), Kurokawa-mura,
Niigata Pref., 2003–11, World Scientiﬁc, Singapore,pp. 363–364 (2004).
K. Oyamatsu and K. Iida: “Equation of state of nuclear matter, neutron rich nuclei in laboratories andpasta nuclei in neutron star crusts”, Prog. Theor.
Phys. Suppl., No. 156, pp. 137–138 (2004).
K. Iida, K. Oyamatsu, and B. A. Sarhan: “Deducing the density dependence of the symmetry energy
from unstable nuclei”, Prog. Theor. Phys. Suppl.,
No. 156, pp. 139–140 (2004).
H. Madokoro, T. Shimizu, and Y. Motizuki: “Importance of prolate neutrino radiation in core-collapse
supernovae: The reason for the prolate geometry of
SN1987A?”, Publ. Astron. Soc. Jpn. 56, 663–669(2004).
K. Iida: “Color superconductivity in ﬁnite quark matter”, Soryushiron Kenkyu 108, No. 5, pp. E7–E9(2004).
H. Ueno, K. Asahi, H. Ogawa, D. Kameda, H. Miyoshi,

275

A. Yoshimi, H. Watanabe, K. Shimada, W. Sato,
K. Yoneda, N. Imai, Y. Kobayashi, M. Ishihara,
and W. D. Schmidt-Ott: “Nuclear moments of nuclei in the neighborhood of the neutron drip line”,
The Labyrinth in Nuclear Structure: Proceedings ofInternational Conference on The Labyrinth in Nuclear Structure, an EPS Nuclear Physics Divisional
Conference, (NCSR Demokritos and others), Crete,
Greece, 2003–7, A. Bracco and C. A. Kalfas, American Institure of Physics, New York, pp. 135–142(2004).
H. Madokoro, T. Shimizu, and Y. Motizuki: “Eﬀects
of small-scale ﬂuctuations of neutrino ﬂux in supernova explosions”, Cosmic Explosions On the 10th
Anniversary of SN1993J (IAU Colloquium 192), Valencia, Spain, 2003–4, J. M. Marcaide and K. W.
Weiler, Springer-Verlag, Berlin, pp. 309–314 (2005).
T. Inakura, H. Imagawa, Y. Hashimoto, M. Yamagami,
S. Mizutori, and K. Matsuyanagi: “Soft octupole vibrations on superdeformed states in nuclei around40
Ca suggested by Skyrme-HF and self-consistent
RPA calculations”, Eur. Phys. J. A 25, Suppl. 1,
545–546 (2005).
K. Yoshida, T. Inakura, M. Yamagami, S. Mizutori,
and K. Matsuyanagi: “Microscopic structure ofnegative-parity vibrations built on superdeformed
states in sulfur isotopes close to the neutron dripline”, Eur. Phys. J. A 25, Suppl. 1, 557–558 (2005).
M. Yamagami: “Collective excitations induced by pairing anti-halo eﬀect”, Eur. Phys. J. A 25, Suppl. 1,
569–570 (2005).
M. Yamagami and V. Nguyen: “Pairing eﬀects on thecollectivity of quadrupole states around 32 Mg”, Eur.
Phys. J. A 25, Suppl. 1, 573–574 (2005).
M. Yamagami: “Impact of self-consistent pairing correlations; spatial structure change of quasiparticles
and enhanced low-lying collectivity in neutron drip
line nuclei”, International Symposium on Correlation Dynamics in Nuclei, Tokyo, 2005–1∼2, Institute of Physics Publishing, London, pp. 213–214(2005).
C. Wu, Y. Yamaguchi, A. Ozawa, I. Tanihata, J.
Dongxing, H. Hui, Z. Tao, L. Zhihuan, and Y.
Yanlin: “Neutron removal reactions of 17 C”, J. Phys.
G 31, 39–47 (2005).
N. D. Dang: “Giant resonances at zero and ﬁnite temperatures”, J. Phys. G 31, S1697–S1700 (2005).
N. D. Dang and A. Arima: “Role of thermal pairing in reducing the giant dipole resonance width at
low temperature”, Key Topics in Nuclear Structure:
Proceedings of the 8th International Spring Seminaron Nucelar Physics, (University of Naples), Paestum, Italy, 2004–5, World Scientiﬁc, Singapore, pp.
409–416 (2005).
Y. Ishida, M. Wada, and H. Wollnik: “A multireﬂection time-of-ﬂight mass spectrometer for massmeasurements of short-lived nuclei”, Nucl. Instrum.

276

Methods Phys. Res. B 241, 983–985 (2005).
J. Pinard, H. T. Duong, D. Marescaux, H. H. Stroke,
O. Redi, M. Gustafsson, T. Nilsson, S. Matsuki,
Y. Kishimoto, K. Kominato, I. Ogawa, M. Shibata,
M. Tada, J. R. Persson, Y. Nojiri, S. Momota, T.
Inamura, M. Wakasugi, P. Juncar, T. Murayama, T.
Nomura, M. Koizumi, and ISOLDE Collaboration:“Precision hfs of 126 Cs (T1/2 = 1.63 m) by ABMR”,
Nucl. Phys. A 753, 3–12 (2005).
R. Kanungo, Z. Elekes, H. Baba, Z. Dombradi, Z.
Fulop, J. Gibelin, A. Horvath, Y. Ichikawa, E.
Ideguchi, N. Iwasa, H. Iwasaki, S. Kawai, Y. Kondo,
T. Motobayashi, M. Notani, T. Ohnishi, A. Ozawa,
H. Sakurai, S. Shimoura, E. Takeshita, S. Takeuchi,
I. Tanihata, Y. Togano, C. Wu, Y. Yamaguchi, Y.
Yanagisawa, A. Yoshida, and K. Yoshida: “Search
for an isomeric state in 19 C”, Nucl. Phys. A 757,
315–328 (2005).
R. G. Zegers, A. L. Cole, H. Akimune, S. M. Austin, D.
Bazin, A. M. van den Berg, G. P. Berg, J. Brown,
I. Daito, Y. Fujita, M. Fujiwara, K. Hara, M. N.
Harakeh, G. W. Hitt, M. E. Howard, J. Janecke,
T. Kawabata, T. Nakamura, H. Ueno, H. Schatz,
B. M. Sherrill, and M. Steiner: “Weak interaction
strengths for supernovae calculations via the (t, 3He)
reaction on medium-heavy nuclei”, Nucl. Phys. A
758, 67c–70c (2005).
T. Yamazaki: “Two-particle wave function in four
dimensional Ising model”, Nucl. Phys. B (Proc.
Suppl.) 140, 338–340 (2005).
K. Ishida, K. Nagamine, T. Matsuzaki, and N.
Kawamura: “Muon catalyzed fusion”, Nucl. Phys.
B (Proc. Suppl.) 149, 348–350 (2005).
P. Strasser, K. Nagamine, T. Matsuzaki, K. Ishida,
Y. Matsuda, and M. Iwasaki: “Muonic atoms of radioactive nuclei”, Nucl. Phys. B (Proc. Suppl.) 149,
390–392 (2005).
A. Kohama, K. Iida, and K. Oyamatsu: “Global viewof nuclei in the black sphere picture”, Nucl. Study
49, No. 6, pp. 27–31 (2005).
T. Matsuzaki, K. Nagamine, K. Ishida, N. Kawamura,
H. Imao, Y. Matsuda, M. Iwasaki, S. Nakamura, M.
Kato, H. Sugai, M. Tanase, K. Kudo, A. Uritani, H.
Harano, and G. H. Eaton: “Particle correlations in
t+t reactions studied by muon catalyzed t-t fusion”,
Nucl. Study 49, No. 6, pp. 191–196 (2005).
Y. Yanagisawa, S. Kubono, T. Teranishi, K. Ue,
S. Michimasa, M. Notani, 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”,
Nuclear Instruments and Methods in Physics Research A 539, 74–83 (2005).
R. Kanungo, Z. Elekes, H. Baba, Z. Dombradi, Z.
Fulop, J. Gibelin, A. Horvath, Y. Ichikawa, E.
Ideguchi, N. Iwasa, H. Iwasaki, S. Kawai, Y. Kondo,
T. Motobayashi, M. Notani, T. Ohnishi, A. Ozawa,H. Sakurai, S. Shimoura, E. Takeshita, S. Takeuchi,
I. Tanihata, Y. Togano, C. Wu, Y. Yamaguchi, Y.
Yanagisawa, A. Yoshida, and K. Yoshida: “Excitedstates in neutron rich boron isotopes”, Phys. Lett.
B 608, 206–214 (2005).
Y. Akaishi, A. Dote, and T. Yamazaki: “Strange tribaryons as K-mediated dense nuclear systems”, Phys.
Lett. B 613, 140–147 (2005).
H. Ueno, D. Kameda, G. Kijima, K. Asahi, A. Yoshimi,
H. Miyoshi, K. Shimada, G. Kato, D. Nagae, S.
Emori, T. Haseyama, H. Watanabe, and M. Tsukui:
32“Magnetic moments of 30
13 Al17 and 13 Al19 ”, Phys.
Lett. B 615, 186–192 (2005).
Y. L. Ye, D. Y. Pang, D. X. Jiang, T. Zheng,
Q. J. Wang, Z. Li, X. O. Li, Y. C. Ge, C. Wu,
G. L. Zhang, Q. Y. Hu, J. Wang, Z. Q. Chen,
A. Ozawa, Y. Yamaguchi, R. Kanungo, and I.
Tanihata: “Quasielastic scattering of 6He on 9Be
at 25 MeV/nucleon”, Phys. Rev. C 71, 014604-1–
014604-8 (2005).
N. D. Dang: “Particle-number conservation within
self-consistent random-phase approximation”, Phys.
Rev. C 71, 024302-1–024302-10 (2005).
M. Takashina, Y. Enyo, and H. Sakuragi: “16 C inelastic scattering studied with microscopic coupledchannels method”, Phys. Rev. C 71, 054602-1–
054602-7 (2005).
A. Kohama, K. Iida, and K. Oyamatsu: “Reaction
cross section described by a black sphere approximation of nuclei”, Phys. Rev. C 72, 024602-1–024602-5(2005).
M. Yamagami: “Continuum eﬀects for many-body correlations in nuclei close to the neutron drip line”,
Phys. Rev. C 72, 064308-1–064308-11 (2005).
T. Inamura: “Laser methods in the study of nuclei,
atoms and molecules”, Phys. Scr. 71, C1–C4 (2005).
A. Yoshimi, K. Asahi, S. Emori, M. Uchida, and S.
Oshima: “Low-frequency nuclear spin maser andsearch for atomic EDM of 129 Xe”, Proceedings of
16th International Spin Physics Symposium (SPIN
2004), (Istituto Nazionale di Fisica Nucleare), Trieste, Italy, 2004–10, World Scientiﬁc Publishing,
Singapore, pp. 247–250 (2005).
N. D. Dang: “Nuclear giant resonances”, Proceedings of 9th Asia Paciﬁc Physics Conference (APPC
2004), (Vietnam Academy of Science and Technology), Hanoi, Vietnam, 2004–10, Institute of material
Science, Hanoi, pp. 1–4 (2005).
M. Yamagami: “Novel coordinate space representation
for deformed loosely-bound nuclei”, Proceedingsof YITP Workshop on New Developments in Nuclear Self-Consistent Mean-Field Theories (MF05),
Kyoto, 2005–5∼6, Kyoto University, Kyoto, p. 46(2005).
H. Koura, T. Tachibana, M. Uno, and M. Yamada:“Nuclidic mass formula on a spherical basis with an
improved even-odd term”, Prog. Theor. Phys. 113,

305–325 (2005).
M. Yamagami, K. Yoshida, and K. Matsuyanagi:“Comparative Study of Octupole Excitations on Superdeformed States in 32 S, 36 S, 40 Ca and 50 S”, Prog.
Theor. Phys. 113, 1251–1272 (2005).
H. Haba and D. Kaji: “A new element from Japan!?
Discovery of the element 113”, Radiochem. News 11,
45–46 (2005).

3.

Atomic and solid-state physics

S. Ohira-Kawamura, M. Tamura, R. Kato, I.
Watanabe, and M. Iwasaki: “µSR study on magnetic property of [Pd(dmit)2 ] salts”, J. Phys. IV
114, 355–356 (2004).
R. Lehnert and I. Shimamura: “Theoretical aspectsof antihydrogen studies”, J. Plasma Fusion Res. 80,
No. 12, pp. 1006–1011 (2004).
H. Torii, N. Kuroda, H. Higaki, R. Funakoshi, and N.
Oshima: “The production, deceleration and coolingof the slow antiproton beam, and the production andcontrol of the positron plasma”, J. Plasma Fusion
Res. 80, No. 12, pp. 1012–1021 (2004).
M. Hori, M. Fujiwara, N. Kuroda, and A. Mohri: “Observation of antiproton beams and nonneutral plasmas”, J. Plasma Fusion Res. 80, No. 12, pp. 1022–
1026 (2004).
M. Fujiwara: “Production of cold antihydrogen in anested trap”, J. Plasma Fusion Res. 80, No. 12, pp.
1027–1030 (2004).
Y. Kanai, A. Mohri, and M. Hori: “Next generation
traps for conﬁnement of extraction of antihydrogenatoms”, J. Plasma Fusion Res. 80, No. 12, pp. 1031–
1034 (2004).
Y. Yamazaki: “Eﬃcient accumulation of antiprotons
and positrons, production of slow mono-energetic
beams, and their applications”, Mater. Sci. Forum
445-446, 430–434 (2004).
K. Kubo, Y. Kobayashi, Y. Yamada, Y. Nemoto, T.
Saito, Y. Sakai, H. Shoji, C. Yonezawa, H. Matsue,
and M. Nakada: “Neutron In-beam Mössbauer Spectroscopy with a Parallel Plate Avalanche Counter”,
AIP Conf. Proc. 765, 348–351 (2005).
B. Juhasz, D. Barna, J. Eades, R. Hayano, M. Hori, D.
Horvath, W. Pirkl, E. Widmann, and Y. Yamazaki:“Measurement of the ground-state hyperﬁne structure of antihydrogen”, AIP Conf. Proc. 796, 243–
246 (2005).
A. Rotondi, M. Amoretti, C. Amsler, G. Bonomi, P.
Bowe, C. Canali, C. Carraro, C. Cesar, M. Charlton,
M. Doser, A. Fontana, M. Fujiwara, R. Funakoshi,
P. Genova, J. Hangst, R. Hayano, L. Jorgensen,
A. Kellerbauer, V. Lagomarsino, R. Landua, E.
Lodi-Rizzini, M. Macri, N. Madsen, G. Manuzio,
P. Montagna, H. Pruys, C. Regenfus, D. Mitchard,
G. Testera, A. Variola, L. Venturelli, Y. Yamazaki,
D. P. van der Werf, and N. Zurlo: “Results from277

ATHENA”, AIP Conf. Proc. 796, 285–290 (2005).
W. Bertsche, A. Boston, P. D. Bowe, C. L. Cesar, S.
Chapman, M. Charlton, M. Chartier, A. Deutsch,
J. Fajans, M. Fujiwara, R. Funakoshi, D. Gill, K.
Gomberoﬀ, D. Grote, J. S. Hangst, R. Hayano, M.
Jenkins, L. V. Jorgensen, N. Madsen, D. Miranda, P.
Nolan, K. Ochanski, A. Olin, R. D. Page, L. Posada,
F. Robicheaux, E. Sarid, H. H. Telle, J. L. Vay, J.
Wurtele, D. P. van der Werf, and Y. Yamazaki: “TheALPHA experiment: A cold antihydrogen trap”,
AIP Conf. Proc. 796, 301–308 (2005).
N. Kuroda, H. Torii, M. Shibata, Y. Nagata, D. Barna,
M. Hori, K. Komaki, and Y. Yamazaki: “Antiprotonand electron plasma behavior and its control for production of ultraslow antiproton beams”, AIP Conf.
Proc. 796, 321–324 (2005).
H. Torii, N. Kuroda, M. Shibata, Y. Nagata, D. Barna,
M. Hori, A. Mohri, K. Komaki, and Y. Yamazaki:“Extraction of ultra-slow antiproton beams andtheir physics application”, AIP Conf. Proc. 796,
413–416 (2005).
T. Kurahashi, Y. Kobayashi, S. Nagatomo, T. Tosha,
T. Kitagawa, and H. Fujii: “Oxidizing intermediatesfrom the sterically hindered iron salen complexes related to the oxygen activation by nonheme iron enzymes”, Inorg. Chem. 44, No. 22, pp. 8156–8166(2005).
Y. Yamazaki: “Physics and Applications of Slow
Highly Charged Ions: A Brief Overview”, J. Vac.
Soc. Jpn. 48, No. 8, pp. 461–465 (2005).
Y. Iwai and Y. Kanai: “Slow highly charged ions andsolid surfaces”, J. Vac. Soc. Jpn. 48, No. 8, pp. 478–
482 (2005).
C. Kondo, Y. Takabayashi, T. Muranaka, S. Masugi,
T. Azuma, K. Komaki, A. Hatakeyama, Y.
Yamazaki, E. Takada, and T. Murakami: “Xray yields from high-energy heavy ions channeledthrough a crystal: their crystal thickness and projectile dependences”, Nucl. Instrum. Methods Phys.
Res. B 230, 85–89 (2005).
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”, Nucl.
Instrum. Methods Phys. Res. B 230, 90–95 (2005).
N. Okabayashi, K. Komaki, and Y. Yamazaki: “Potential sputtering and kinetic sputtering from a water
adsorbed Si(100) surface with slow highly chargedions”, Nucl. Instrum. Methods Phys. Res. B 232,
244–248 (2005).
N. Nakamura, M. Terada, Y. Nakai, Y. Kanai, S.
Ohtani, K. Komaki, and Y. Yamazaki: “SPM observation of nano-dots induced by slow highly chargedions”, Nucl. Instrum. Methods Phys. Res. B 232,
261–265 (2005).
Y. Kanai, Y. Nakai, Y. Iwai, T. Ikeda, M. Hoshino, K.
Nishio, H. Masuda, and Y. Yamazaki: “X-ray mea-278

surements of highly charged Ar ions passing througha Ni microcapillary: coincidence of L X-rays and ﬁnal charge states”, Nucl. Instrum. Methods Phys.
Res. B 233, 103–110 (2005).
H. Shimada, Y. Nakai, H. Oyama, K. Ando, T.
Kambara, A. Hatakeyama, and Y. Yamazaki:“Recoil-ion momentum spectroscopy of multiply
charged argon ions produced by intense (∼1016 W
cm−2 ) laser light”, Nucl. Instrum. Methods Phys.
Res. B 235, 221–225 (2005).
M. Hoshino, T. Kambara, R. H. Schuch, and Y.
Yamazaki: “Multi-electron processes in large-angle
scattering between slow Neq+ (q = 1, 2 and 3) andAr”, Nucl. Instrum. Methods Phys. Res. B 235, 347–
351 (2005).
N. Okabayashi, K. Komaki, and Y. Yamazaki:“Energy- and angular-distributions of F+ ions emitted from a F-terminated Si(100) surface with slow
highly charged ions”, Nucl. Instrum. Methods Phys.
Res. B 235, 438–442 (2005).
M. Terada, N. Nakamura, Y. Nakai, Y. Kanai, S.
Ohtani, K. Komaki, and Y. Yamazaki: “Observation of an HCI-induced nano-dot on an HOPG surface with STM and AFM”, Nucl. Instrum. Methods
Phys. Res. B 235, 452–455 (2005).
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 microcapillarytarget”, Nucl. Instrum. Methods Phys. Res. B 235,
468–472 (2005).
N. Oshima, M. Niigaki, M. Lebois, A. Mohri, K.
Komaki, and Y. Yamazaki: “Simultaneous coolingof highly charged ions with electrons and positrons”,
Nucl. Instrum. Methods Phys. Res. B 235, 504–508(2005).
N. Kuroda, H. A. Torii, K. Yoshiki-Franzen, Z. Wang,
S. Yoneda, M. Inoue, M. Hori, B. Juhász, D.
Horváth, H. Higaki, A. Mohri, J. Eades, K. Komaki,
and Y. Yamazaki: “Conﬁnement of a large number of antiprotons and production of an ultraslow
antiproton beam”, Phys. Rev. Lett. 94, 023401-1–
023401-4 (2005).
N. Madsen, M. Amoretti, C. Amsler, G. Bonomi, P.
Bowe, C. Carraro, C. Cesar, M. Charlton, M. Doser,
A. Fontana, M. Fujiwara, R. Funakoshi, P. Genova,
J. Hangst, R. Hayano, L. Jorgensen, A. Kellerbauer,
V. Lagomarsino, R. Landua, E. Lodi-Rizzini, M.
Macri, D. Mitchard, P. Montagna, H. Pruys, C.
Regenfus, A. Rotondi, G. Testera, A. Variola, L.
Venturelli, D. P. van der Werf, Y. Yamazaki, andN. Zurlo: “Spatial distribution of cold antihydrogenformation”, Phys. Rev. Lett. 94, 033403-1–033403-4(2005).
L. Jorgensen, M. Amoretti, G. Bonomi, P. Bowe,
C. Canali, C. Carraro, C. Cesar, M. Charlton, M.
Doser, A. Fontana, M. Fujiwara, R. Funakoshi, P.

Genova, J. Hangst, R. Hayano, A. Kellerbauer, V.
Lagomarsino, R. Landua, E. Rizzini, M. Macri, N.
Madsen, D. Mitchard, P. Montagna, A. Rotondi,
G. Testera, A. Variola, L. Venturelli, D. P. vander Werf, and Y. Yamazaki: “New source of dense,
cryogenic positron plasmas”, Phys. Rev. Lett. 95,
025002-1–025002-5 (2005).
A. Mohri, Y. Kanai, Y. Nakai, and Y. Yamazaki:“Non-neutral plasma conﬁnement in a cusp-trap andpossible application to anti-hydrogen beam generation”, Physics with Ultra Slow Antiproton Beams,
Wako, 2005–3, American Institute of Physics, New
York, pp. 147–158 (2005).
K. Nagamine: “Muonic anti-hydrogen: formation andtest of CPT theorem”, Physics with Ultra Slow Antiproton Beams, Wako, 2005–3, American Instituteof Physics, New York, pp. 159–164 (2005).
M. Wada and Y. Yamazaki: “Antiprotonic Radioactive
atom for nuclear structure studies”, Physics with Ultra Slow Antiproton Beams, Wako, 2005–3, American Institute of Physics, New York, pp. 223–241(2005).
H. Torii, N. Kuroda, M. Shibata, Y. Nagata, D. Barna,
M. Hori, J. Eades, A. Mohri, K. Komaki, andY. Yamazaki: “Production of ultra-slow antiproton
beams”, Physics with Ultra Slow Antiproton Beams,
Wako, 2005–3, American Institute of Physics, New
York, pp. 293–306 (2005).
N. Kuroda, H. Torii, M. Shibata, Y. Nagata, D.
Barna, D. Horvath, M. Hori, J. Eades, A. Mohri, K.
Komaki, and Y. Yamazaki: “Control of plasmas for
production of ultraslow antiprotons beams”, Physics
with Ultra Slow Antiproton Beams, Wako, 2005–3,
American Institute of Physics, New York, pp. 307–317 (2005).
V. Varentsov, N. Kuroda, Y. Nagata, H. Torii, M.
Shibata, and Y. Yamazaki: “ASACUSA Gas-Jet
Target: Present status and future development”,
Physics with Ultra Slow Antiproton Beams, Wako,
2005–3, American Institute of Physics, New York,
pp. 328–340 (2005).

4. Radiochemistry, radiation chemistry, and radiation biology
F. Yatagai: “Mutation Induced by Heavy Charged
Particles”, Biol. Sci. Space 18, No. 4, pp. 224–234(2004).
A. Toyoshima, H. Haba, K. Tsukada, 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: “Elution
curve of rutherfordium (Rf) in anion-exchange chromatography with hydroﬂuoric acid solution”, J.
Nucl. Radiochem. Sci. 5, 45–48 (2004).
T. Shinonaga and S. Ambe: “Translocation of radionu-

clides of Co, Zn, Se, Rb, Y, Tc, and Re into organsof tomato plant via roots”, Biol. Trace Elem. Res.
104, 71–82 (2005).
H. Haba: “Atom-at-a-time chemistry of the superheavy elements: Anion-exchange chromatography ofelement 104, rutherfordium”, Kagaku to Kogyo 58,
105–108 (2005).
T. Abe and S. Yoshida: “Mutation breeding (Heavy
ion beam)”, Nogyo Gijutsu Taikei Addendum, Rural Culture Association, Tokyo, pp. 124-2–124-11(2005).
T. Abe: “Ion-beam irradiation on mutation breeding for ornamental plants”, Proceedings of the
5th Technical Seminar on Accelerator Application,(Radiation Application Development Association),
Kagoshima, 2005–10, Radiation Application Development Association, Kagoshima, pp. 53–57 (2005).

5.

Material Analysis

N. Inada, K. Maeda, and J. Kawai: “Strong X-ray
emission from electriﬁed insulators”, Anal. Sci. 21,
877–880 (2005).
K. Maeda, K. Hasegawa, M. Maeda, K. Ogiwara, and
H. Hamanaka: “Rapid chemical state analysis in air
by highly sensitive high-resolution PIXE using a v.
Hamos crystal spectrometer”, X-Ray Spectrometry
34, 389–392 (2005).

6.

RIKEN-BNL Collaboration

S. George and W. Vogelsang: “Threshold resummation
and rapidity dependence”, J. High-Energy Phys.,
pp. 02(2001)016-1–02(2001)016-24 (2001).
N. Ishii, H. Suganuma, and H. Matsufuru: “The thermal width of the glueball at non-zero temperature”,
Nucl. Phys. B (Proc. Suppl.) 119, 484–486 (2003).
N. Ishii, H. Suganuma, and H. Matsufuru: “The thermal glueball in SU(3) anisotropic lattice QCD”,
Quark Conﬁnement and the Hadron Spectrum V,(National Institute for Nuclear Physics and Milano
University), Gargnano, Italy, 2002–9, World Scientiﬁc, Singapore, pp. 387–389 (2003).
T. Izubuchi: “BK from two-ﬂavor dynamical domain wall fermions”, Nucl. Phys. B (Proc. Suppl.)
129/130, 266–268 (2004).
T. Doi, Y. Kondo, and M. Oka: “Meson-baryon couplings from QCD sum rules”, Phys. Rep. 398, 253–
279 (2004).
S. S. Adler, Y. Akiba, A. V. Bazilevsky, G. M.
Bunce, A. Deshpande, H. En’yo, D. E. Fields, B.
Fox, Y. Goto, M. Grosse Perdekamp, T. Ichihara,
K. Imai, M. Ishihara, O. Jinnouchi, N. Kamihara,
H. Kobayashi, K. Kurita, Y. Mao, J. Murata, H.
Ohnishi, K. Okada, N. Saito, H. Sato, T. Shibata,A. Taketani, K. Tanida, J. Tojo, H. Torii, Y.
Watanabe, S. Yokkaichi, and PHENIX Collaboration: “J/ψ production in Au-Au collisions at

279

√sN N = 200 GeV”, Phys. Rev. C 69, 014901-1–
014901-10 (2004).
K. Adcox, A. Bazilevsky, G. M. Bunce, A. Deshpande,
H. En’yo, Y. Goto, M. Grosse Perdekamp, N.
Hayashi, T. Ichihara, K. Imai, M. Ishihara, B.
Jacak, K. Kurita, Z. Li, Y. Mao, J. Murata,
N. Saito, T. Sakuma, H. Sato, T. Shibata, M.
Sugioka, A. Taketani, E. Taniguchi, J. Tojo, H.
Torii, Y. Watanabe, S. Yokkaichi, and PHENIX Collaboration: “Single identiﬁed hadron spectra from√sN N = 130 GeV Au+Au collisions”, Phys. Rev. C
69, 024904-1–024904-29 (2004).
S. S. Adler, Y. Akiba, A. V. Bazilevsky, G. M.
Bunce, A. Deshpande, H. En’yo, D. E. Fields, B.
Fox, Y. Goto, M. Grosse Perdekamp, T. Ichihara,
K. Imai, M. Ishihara, O. Jinnouchi, N. Kamihara,
H. Kobayashi, K. Kurita, Y. Mao, J. Murata, H.
Ohnishi, K. Okada, N. Saito, H. Sato, T. Shibata, A.
Taketani, K. Tanida, J. Tojo, H. Torii, Y. Watanabe,
S. Yokkaichi, and PHENIX Collaboration: “Identiﬁed charged particle spectra and yields in Au+Au√
collisions at sN N = 200 GeV”, Phys. Rev. C 69,
034909-1–034909-32 (2004).
S. S. Adler, Y. Akiba, A. V. Bazilevsky, G. M.
Bunce, A. Deshpande, H. En’yo, D. E. Fields, B.
Fox, Y. Goto, M. Grosse Perdekamp, T. Ichihara,
K. Imai, M. Ishihara, O. Jinnouchi, N. Kamihara,
H. Kobayashi, K. Kurita, Y. Mao, J. Murata, H.
Ohnishi, K. Okada, N. Saito, H. Sato, T. Shibata, A.
Taketani, K. Tanida, J. Tojo, H. Torii, Y. Watanabe,
S. Yokkaichi, and PHENIX Collaboration: “HighpT charged hadron suppression in Au+Au collisions√
at sN N = 200 GeV”, Phys. Rev. C 69, 034910-1–
034910-20 (2004).
Y. Hatta and K. Fukushima: “Linking the chiral anddeconﬁnement phase transitions”, Phys. Rev. D 69,
097502-1–097502-4 (2004).
T. Doi, N. Ishii, M. Oka, and H. Suganuma:“Thermal eﬀects on quark-gluon mixed condensategq̄σµν Gµν q from lattice QCD”, Phys. Rev. D 70,
034510-1–034510-5 (2004).
S. Prelovsek, C. Dawson, T. Izubuchi, K. N. Orginos,and A. Soni: “Scalar meson in dynamical and partially quenched two-ﬂavor QCD: lattice results andchiral loops”, Phys. Rev. D 70, 094503-1–094503-13(2004).
S. S. Adler, Y. Akiba, A. V. Bazilevsky, G. M.
Bunce, A. Deshpande, H. En’yo, D. E. Fields, B.
Fox, Y. Goto, M. Grosse Perdekamp, T. Ichihara,
K. Imai, M. Ishihara, O. Jinnouchi, N. Kamihara,
H. Kobayashi, K. Kurita, Y. Mao, J. Murata, H.
Ohnishi, K. Okada, N. Saito, H. Sato, T. Shibata, A.
Taketani, K. Tanida, J. Tojo, H. Torii, Y. Watanabe,
S. Yokkaichi, and PHENIX Collaboration: √“J/ψ
Production from Proton-Proton Collisions at s =200 GeV”, Phys. Rev. Lett. 92, No. 5, pp. 0518021–051802-6 (2004).

280

S. S. Adler, Y. Akiba, A. V. Bazilevsky, G. M.
Bunce, A. Deshpande, H. En’yo, D. E. Fields, B.
Fox, Y. Goto, M. Grosse Perdekamp, T. Ichihara,
K. Imai, M. Ishihara, O. Jinnouchi, N. Kamihara,
H. Kobayashi, K. Kurita, Y. Mao, J. Murata, H.
Ohnishi, K. Okada, N. Saito, H. Sato, T. Shibata,A. Taketani, K. Tanida, J. Tojo, H. Torii, Y.
Watanabe, S. Yokkaichi, and PHENIX Collaboration: “Bose-Einstein Correlations of Charged Pion√
Pairs in Au+Au Collisions at sN N = 200 GeV”,
Phys. Rev. Lett. 93, No. 15, pp. 152302-1–152302-6(2004).
S. S. Adler, Y. Akiba, A. V. Bazilevsky, G. M. Bunce,
A. Deshpande, H. En’yo, D. E. Fields, B. Fox, Y.
Fukao, Y. Goto, M. Grosse Perdekamp, K. Hasuko,
J. M. Heuser, T. Horaguchi, T. Ichihara, K. Imai, M.
Ishihara, O. Jinnouchi, N. Kamihara, M. Kaneta,
A. Kiyomichi, H. Kobayashi, K. Kurita, Y. Mao,
H. Ohnishi, H. Okada, K. Okada, V. L. Rykov, N.
Saito, H. Sato, T. Shibata, A. Taketani, K. Tanida,
M. Togawa, J. Tojo, H. Torii, Y. Watanabe, S.
Yokkaichi, and PHENIX Collaboration: “Double0
Helicity Asymmetry in Inclusive Mid-Rapidity√ π
Production for Polarized p + p Collisions at s =200 GeV”, Phys. Rev. Lett. 93, No. 20, pp. 2020021–202002-6 (2004).
S. S. Adler, Y. Akiba, A. V. Bazilevsky, G. M.
Bunce, A. Deshpande, H. En’yo, D. E. Fields, B.
Fox, Y. Goto, M. Grosse Perdekamp, T. Ichihara,
K. Imai, M. Ishihara, O. Jinnouchi, N. Kamihara,
H. Kobayashi, K. Kurita, Y. Mao, J. Murata, H.
Ohnishi, K. Okada, N. Saito, H. Sato, T. Shibata, A.
Taketani, K. Tanida, J. Tojo, H. Torii, Y. Watanabe,
S. Yokkaichi, and PHENIX Collaboration: “Measurement of Nonrandom Event-by-Event Fluctua√
tions of Average Transverse Momentum in sN N =200 GeV Au+Au and p + p Collisions”, Phys. Rev.
Lett. 93, No. 9, pp. 092301-1–092301-6 (2004).
T. Izubuchi: “The electromagnetic splitting and gµ −2light-by-light contribution”, Proceedings of RIKEN
BNL Research Center Workshop 68, 99–104 (2004).
T. Nishikawa, A. Iwazaki, O. Morimatsu, and
M. Ohtani: “Coexistence of color ferromagnetic
state and color superconducting state”, Soryushiron
Kenkyu 109, No. 6, p. 82 (2004).
M. Oka, J. Sugiyama, and T. Doi: “Pentaquark
baryons in the QCD sum rule”, Nucl. Phys. A 755,
391c–394c (2005).
N. Ishii, T. Doi, H. Iida, M. Oka, F. Okiharu, and
H. Suganuma: “Penta-quark in anisotropic lattice
QCD”, Nucl. Phys. A 755, 467–470 (2005).
M. Ohtani and K. Ohta: “Spin polarized Skyrmionsin the UEM (1) gauged Wess-Zumino action”, Nucl.
Phys. A 755, 661–664 (2005).
K. Adcox, Y. Akiba, K. Aoki, A. Bazilevsky, G. M.
Bunce, A. Deshpande, H. En’yo, D. E. Fields, B.
Fox, Y. Fukao, Y. Goto, M. Grosse Perdekamp,

T. Hachiya, K. Hasuko, N. Hayashi, J. Heuser, T.
Horaguchi, T. Ichihara, K. Imai, M. Ishihara, B.
Jacak, O. Jinnouchi, F. Kajihara, N. Kamihara, M.
Kaneta, A. Kiyomichi, H. Kobayashi, K. Kurita, Z.
Li, Y. Mao, J. Murata, H. Onishi, H. Okada, K.
Okada, V. Rykov, N. Saito, T. Sakuma, H. Sato,T. Shibata, K. Shoji, M. Sugioka, T. Tabaru, A.
Taketani, K. Tanida, E. Taniguchi, M. Togawa,J. Tojo, H. Torii, Y. Tsuchimoto, Y. Watanabe,
W. Xie, S. Yokkaichi, and PHENIX Collaboration:“Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX Collaboration”, Nucl.
Phys. A 757, 184–283 (2005).
T. Izubuchi: “Hadron spectrum and decay constantfrom NF = 2 domain wall QCD”, Nucl. Phys. B(Proc. Suppl.) 140, 237–239 (2005).
N. Ishii, T. Doi, H. Iida, M. Oka, F. Okiharu,
and H. Suganuma: “Penta-quark anti-decuplet inanisotropic lattice QCD”, Nucl. Phys. B (Proc.
Suppl.) 140, 269–271 (2005).
K. Hashimoto and T. Izubuchi: “Static Q̄-Q potentialfrom Nf = 2 dynamical domain-wall QCD”, Nucl.
Phys. B (Proc. Suppl.) 140, 341–343 (2005).
T. Doi, N. Ishii, M. Oka, and H. Suganuma: “Thelattice QCD simulation of the quark-gluon mixed
condensate gq̄σµν Gµν q at ﬁnite temperature andthe phase transition of QCD”, Nucl. Phys. B (Proc.
Suppl.) 140, 559–561 (2005).
N. Ishii, T. Doi, H. Iida, M. Oka, F. Okiharu, and
H. Suganuma: “Anisotropic lattice QCD studies
of penta-quark anti-decuplet”, PENTAQUARK04:
Proceedings of the International Workshop, (RCNP
and JASRI), Harima, 2004–7, World Scientiﬁc, Singapore, pp. 316–323 (2005).
J. Sugiyama, T. Doi, and M. Oka: “Pentaquark
baryon from the QCD sum rule with the ideal mixing”, PENTAQUARK04: Proceedings of the International Workshop, (RCNP and JASRI), Harima,
2004–7, World Scientiﬁc, Singapore, pp. 354–357(2005).
S. S. Adler, Y. Akiba, A. Bazilevsky, G. M. Bunce,
A. Deshpande, H. En’yo, D. E. Fields, B. Fox,
Y. Goto, M. Grosse Perdekamp, T. Ichihara, K.
Imai, M. Ishihara, O. Jinnouchi, N. Kamihara,
H. Kobayashi, K. Kurita, Y. Mao, J. Murata, H.
Onishi, K. Okada, N. Saito, H. Sato, T. Shibata, A.
Taketani, K. Tanida, J. Tojo, H. Torii, Y. Watanabe,
S. Yokkaichi, and PHENIX Collaboration: “System√
atic studies of the centrality and sN N dependenceof the dET /dη and dNch /dη in heavy ion collisions at
midrapidity”, Phys. Rev. C 71, 034908-1–034908-25(2005).
S. S. Adler, Y. Akiba, A. Bazilevsky, G. M. Bunce,
A. Deshpande, H. En’yo, D. E. Fields, B. Fox, Y.
Fukao, Y. Goto, M. Grosse Perdekamp, K. Hasuko,
N. Hayashi, J. Heuser, T. Horaguchi, T. Ichihara, K.

Imai, M. Ishihara, O. Jinnouchi, N. Kamihara, M.
Kaneta, A. Kiyomichi, H. Kobayashi, K. Kurita, Y.
Mao, J. Murata, H. Onishi, H. Okada, K. Okada, V.
Rykov, N. Saito, H. Sato, T. Shibata, A. Taketani,
J. Tojo, H. Torii, Y. Watanabe, S. Yokkaichi, and
PHENIX Collaboration: “Jet structure of baryon√
excess in Au+Au collisions at sN N = 200 GeV”,
Phys. Rev. C 71, 051902-1–051902-6 (2005).
S. S. Adler, Y. Akiba, A. Bazilevsky, G. M. Bunce,
A. Deshpande, H. En’yo, D. E. Fields, B. Fox,
Y. Goto, M. Grosse Perdekamp, N. Hayashi, T.
Ichihara, K. Imai, M. Ishihara, O. Jinnouchi, N.
Kamihara, H. Kobayashi, K. Kurita, Y. Mao, J.
Murata, H. Onishi, K. Okada, N. Saito, H. Sato, T.
Shibata, A. Taketani, K. Tanida, J. Tojo, H. Torii,
Y. Watanabe, S. Yokkaichi, and PHENIX Collaboration: “Production of φ mesons at midrapidity√
in sN N = 200 GeV Au+Au collisions at relativistic energies”, Phys. Rev. C 72, 014903-1–014903-23(2005).
S. S. Adler, Y. Akiba, A. Bazilevsky, G. M. Bunce, A.
Deshpande, H. En’yo, D. E. Fields, B. Fox, Y. Goto,
M. Grosse Perdekamp, N. Hayashi, T. Ichihara,
K. Imai, M. Ishihara, O. Jinnouchi, N. Kamihara,
H. Kobayashi, K. Kurita, Y. Mao, J. Murata, H.
Onishi, K. Okada, N. Saito, H. Sato, T. Shibata, A.
Taketani, K. Tanida, J. Tojo, H. Torii, Y. Watanabe,
S. Yokkaichi, and PHENIX Collaboration: “Measurement of single electron event anisotropy in√
Au+Au collisions at sN N = 200 GeV”, Phys. Rev.
C 72, 024901-1–024901-10 (2005).
N. Ishii, T. Doi, H. Iida, M. Oka, F. Okiharu, and
H. Suganuma: “Pentaquark baryon in anisotropic
lattice QCD”, Phys. Rev. D 71, 034001-1–03400111 (2005).
A. Iwazaki, O. Morimatsu, T. Nishikawa, and M.
Ohtani: “Quantum Hall states of gluons in dense
quark matter”, Phys. Rev. D 71, 034014-1–03401412 (2005).
K. Iida, T. Matsuura, M. Tachibana, and T. Hatsuda:“Thermal phase transitions and gapless quark spectra in quark matter at high density”, Phys. Rev. D
71, 054003-1–054003-15 (2005).
K. Iida: “Magnetic vortex in color-ﬂavor locked
quark matter”, Phys. Rev. D 71, 054011-1–054011-7(2005).
S. S. Adler, Y. Akiba, A. Bazilevsky, G. M. Bunce, A.
Deshpande, H. En’yo, D. E. Fields, B. Fox, Y. Goto,
M. Grosse Perdekamp, N. Hayashi, T. Ichihara,
K. Imai, M. Ishihara, O. Jinnouchi, N. Kamihara,
H. Kobayashi, K. Kurita, Y. Mao, J. Murata, H.
Onishi, K. Okada, N. Saito, H. Sato, T. Shibata, A.
Taketani, K. Tanida, J. Tojo, H. Torii, Y. Watanabe,
S. Yokkaichi, and PHENIX Collaboration: “Midrapidity
direct-photon production in p + p collisions at√
s = 200 GeV”, Phys. Rev. D 71, 071102-1–0711027 (2005).

281

K. Fukushima and K. Iida: “Collective excitations in
a superﬂuid of color-ﬂavor locked quark matter”,
Phys. Rev. D 71, 074011-1–074011-16 (2005).
K. Iida: “Feedback eﬀects on the pairing interaction incolor superconductors near the transition temperature”, Phys. Rev. D 72, 054025-1–054025-7 (2005).
N. Ishii, T. Doi, Y. Nemoto, M. Oka, and H.
Suganuma: “Spin 3/2 Penta-quarks in anisotropic
lattice QCD”, Phys. Rev. D 72, 074503-1–07450315 (2005).
S. S. Adler, Y. Akiba, A. Bazilevsky, G. M. Bunce, A.
Deshpande, H. En’yo, D. E. Fields, B. Fox, Y. Goto,
M. Grosse Perdekamp, N. Hayashi, T. Ichihara,
K. Imai, M. Ishihara, O. Jinnouchi, N. Kamihara,
H. Kobayashi, K. Kurita, Y. Mao, J. Murata, H.
Onishi, K. Okada, N. Saito, H. Sato, T. Shibata, A.
Taketani, K. Tanida, J. Tojo, H. Torii, Y. Watanabe,
S. Yokkaichi, and PHENIX Collaboration: “Centrality dependence of charm production from a measurement of single electrons in Au+Au collisions at√
sN N = 200 GeV”, Phys. Rev. Lett. 94, 082301-1–
082301-6 (2005).
S. S. Adler, Y. Akiba, A. Bazilevsky, G. M. Bunce,
A. Deshpande, H. En’yo, D. E. Fields, B. Fox, Y.
Fukao, Y. Goto, M. Grosse Perdekamp, K. Hasuko,
J. Heuser, T. Horaguchi, T. Ichihara, K. Imai, M.
Ishihara, O. Jinnouchi, N. Kamihara, M. Kaneta,
A. Kiyomichi, H. Kobayashi, K. Kurita, Y. Mao,
H. Onishi, H. Okada, K. Okada, V. Rykov, N.
Saito, H. Sato, T. Shibata, A. Taketani, K. Tanida,
M. Togawa, J. Tojo, H. Torii, Y. Watanabe, S.
Yokkaichi, and PHENIX Collaboration: “Nuclear
modiﬁcation factors for hadrons at forward andbackward rapidities in deuteron-gold collisions at√
sN N = 200 GeV”, Phys. Rev. Lett. 94, 0823021–082302-6 (2005).
S. S. Adler, Y. Akiba, A. Bazilevsky, G. M. Bunce,
A. Deshpande, H. En’yo, D. E. Fields, B. Fox,
Y. Goto, M. Grosse Perdekamp, N. Hayashi, T.
Ichihara, K. Imai, M. Ishihara, O. Jinnouchi, N.
Kamihara, H. Kobayashi, K. Kurita, Y. Mao, J.
Murata, H. Onishi, K. Okada, N. Saito, H. Sato, T.
Shibata, A. Taketani, K. Tanida, J. Tojo, H. Torii,
Y. Watanabe, S. Yokkaichi, and PHENIX Collaboration: “Deuteron and antideuteron production in√
Au+Au collisions at sN N = 200 GeV”, Phys. Rev.
Lett. 94, 122302-1–122302-6 (2005).
S. S. Adler, Y. Akiba, A. Bazilevsky, G. M. Bunce, A.

282

Deshpande, H. En’yo, D. E. Fields, B. Fox, Y. Goto,
M. Grosse Perdekamp, N. Hayashi, T. Ichihara,
K. Imai, M. Ishihara, O. Jinnouchi, N. Kamihara,
H. Kobayashi, K. Kurita, Y. Mao, J. Murata, H.
Onishi, K. Okada, N. Saito, H. Sato, T. Shibata, A.
Taketani, K. Tanida, J. Tojo, H. Torii, Y. Watanabe,
S. Yokkaichi, and PHENIX Collaboration: “Centrality dependence of direct photon production in√sN N = 200 GeV Au+Au collisions”, Phys. Rev.
Lett. 94, 232301-1–232301-6 (2005).
S. S. Adler, Y. Akiba, K. Aoki, A. Bazilevsky, G. M.
Bunce, A. Deshpande, H. En’yo, D. E. Fields, B.
Fox, Y. Fukao, Y. Goto, M. Grosse Perdekamp,
T. Hachiya, K. Hasuko, N. Hayashi, J. Heuser, T.
Horaguchi, T. Ichihara, K. Imai, M. Ishihara, O.
Jinnouchi, S. Kametani, N. Kamihara, M. Kaneta,
A. Kiyomichi, H. Kobayashi, K. Kurita, Y. Mao, J.
Murata, H. Onishi, K. Okada, V. Rykov, N. Saito, H.
Sato, T. Shibata, K. Shoji, T. Tabaru, A. Taketani,
K. Tanida, J. Tojo, H. Torii, Y. Tsuchimoto, Y.
Watanabe, W. Xie, S. Yokkaichi, and PHENIX Collaboration: “Saturation of azimuthal anisotropy in√
Au+Au collisions at sN N = 62-200 GeV”, Phys.
Rev. Lett. 94, 232302-1–232302-6 (2005).
S. S. Adler, Y. Akiba, A. Bazilevsky, G. M. Bunce,
A. Deshpande, H. En’yo, D. E. Fields, B. Fox,
Y. Goto, M. Grosse Perdekamp, N. Hayashi, T.
Ichihara, K. Imai, M. Ishihara, O. Jinnouchi, N.
Kamihara, H. Kobayashi, K. Kurita, Y. Mao, J.
Murata, H. Onishi, K. Okada, N. Saito, H. Sato, T.
Shibata, A. Taketani, K. Tanida, J. Tojo, H. Torii,
Y. Watanabe, S. Yokkaichi, and PHENIX Collaboration: “Measurement of transverse single-spin asymmetries for midrapidity production of neutral pions
and√charged hadrons in polarized p + p collisions
at s = 200 GeV”, Phys. Rev. Lett. 95, 202001-1–
202001-6 (2005).
T. Doi, N. Ishii, Y. Nemoto, M. Oka, and H.
Suganuma: “Anisotropic lattice QCD study of pentaquark baryons in spin 3/2 channel”, Proceedingsof Science (LAT2005), 064-1–064-6 (2005).
H. Iida, T. Doi, N. Ishii, and H. Suganuma: “J/Ψ athigh temperatures in anisotropic lattice QCD”, Proceedings of Science (LAT2005), 184-1–184-6 (2005).
M. Ohtani and K. Ohta: “Spin polarized Skyrmions in
the UEM (1) gauged Wess-Zumino term”, Soryushiron Kenkyu 111, No. 3, p. 18 (2005).

VII. LIST OF PREPRINTS2005
RIKEN-AF-NP
462 Y. Akaishi, A. Doté, and T. Yamazaki: “Strange tribaryons as K̄-mediated dense nuclear systems”
463 Y. Hashimoto and T. Horibata: “Tilted axis rotation in hartree-fock framework”
464 M. Takashina, Y. Kanada-En’yo, and Y. Sakuragi: “16 C inelastic scattering studied with microscopic
coupled-channels method”
465 M. Yamagami: “Spatially extended coherence induced by pairing correlation in low-frequency vibrational
excitations of neutron drip line nuclei”
466 T. Yamazaki: “Overview: deeply bound nuclear states of pions and kaons”
467 Y. Akaishi: “Kaonic helium atoms in relation to kaonic nuclear bound states”
468 P. Kienle, Y. Akaishi, and T. Yamazaki: “Momentum correlation in the three-body decay of high-density
K̄ nuclear clusters: N N N K̄ → N + N + Λ”
469 S. Michimasa, S. Shimoura, H. Iwasaki, M. Tamaki, S. Ota, N. Aoi, H. Baba, N. Iwasa, S. Kanno, S. Kubono,
K. Kurita, M. Kurokawa, T. Minemura, T. Motobayashi, M. Notani, H. J. Ong, A. Saito, H. Sakurai, E.
Takeshita, S. Takeuchi, Y. Yanagisawa, and A. Yoshida: “Proton single-particle states in the neutron-rich
23
F nucleus”
470 T. Matsumoto, T. Egami, K. Ogata. Y. Iseri, M. Kamimura, amd M. Yahiro: “Coulomb breakup eﬀects on
the elastic cross section of 6 He + 209 Bi scattering near coulomb barrier energies”

RIKEN-AF-AC
Not applicable283

VIII. PAPERS PRESENTED AT MEETINGS
1. Accelerator
physics

development

andaccelerator

M. Kidera, T. Nakagawa, S. Enomoto, K. Takahashi,
K. Igarashi, M. Fujimaki, E. Ikezawa, O. Kamigaito,
M. Kase, and Y. Yano: “Novel technique for traceelement analysis using ECRIS and heavy ion linear accelerator”, 16th International Conference on
ECR Ion Sources (ECRIS 04), Berkeley, USA, Sept.
(2004).
N. Fukunishi, A. Goto, O. Kamigaito, M. Kase, H.
Okuno, N. Sakamoto, R. Taki, M. Wakasugi, Y.
Yano, and H. Okamura: “Beam quality studies
on RIKEN Ring Cyclotrons and RI Beam Factory project”, 17th International Conference on Cyclotrons and Their Applications (Cyclotrons 2004),
Tokyo, Oct. (2004).
H. Ryuto, N. Fukunishi, A. Goto, H. Hasebe, N. Inabe,
M. Kase, Y. Yano, and S. Yokouchi: “Charge stripping plan of the RIKEN RI-Beam Factory”, 17th
International Conference on Cyclotrons and Their
Applications (Cyclotrons 2004), Tokyo, Oct. (2004).
M. Kase, T. Fujinawa, E. Ikezawa, K. Yamaguchi, andY. Yano: “Co-generation system for the RIBF accelerators”, 17th International Conference on Cyclotrons and Their Applications (Cyclotrons 2004),
Tokyo, Oct. (2004).
N. Sakamoto, A. Goto, O. Kamigaito, M. Kase, andY. Yano: “Construction of the RF-resonator for the
RIKEN Superconducting Ring Cyclotrons(SRC)”,
17th International Conference on Cyclotrons andTheir Applications (Cyclotrons 2004), Tokyo, Oct.
(2004).
J. Ohnishi, M. Fujimaki, N. Fukunishi, A. Goto, K.
Ikegami, O. Kamigaito, M. Kase, K. Kumagai, M.
Nagase, H. Okuno, N. Sakamoto, T. Tanabe, Y.
Yano, S. Yokouchi, and T. Mitsumoto: “Construction status of the RIKEN Intermediate-stage Ring
Cyclotron (IRC)”, 17th International Conference
on Cyclotrons and Their Applications (Cyclotrons
2004), Tokyo, Oct. (2004).
M. Komiyama, M. Fujimaki, M. Kase, I. Yokoyama,
and J. Odagiri: “Control system for the RIKEN
accelerator research facility and RI-Beam Factory”,
17th International Conference on Cyclotrons andTheir Applications (Cyclotrons 2004), Tokyo, Oct.
(2004).
S. Enomoto, H. Haba, R. Hirunuma, K. Igarashi, S.
Motomura, H. Takeichi, and D. Kaji: “Developmentof a gas-jet-coupled multitracer system for multitracer production and its application for bioscience”,
17th International Conference on Cyclotrons andTheir Applications (Cyclotrons 2004), Tokyo, Oct.
(2004).
N. Inabe, N. Fukunishi, A. Goto, M. Kase, H.

284

Ryuto, N. Sakamoto, Y. Yano, S. Yokouchi, and T.
Mitsumoto: “Fixed-frequency Ring Cyclotron (fRC)
in RIBF”, 17th International Conference on Cyclotrons and Their Applications (Cyclotrons 2004),
Tokyo, Oct. (2004).
T. Tominaka, H. Okuno, S. Fujishima, M. Ohtake, T.
Chiba, J. Ohnishi, K. Ikegami, A. Goto, and Y.
Yano: “Helium vapor-cooled current leads for the
RIKEN SRC”, 17th International Conference on Cyclotrons and Their Applications (Cyclotrons 2004),
Tokyo, Oct. (2004).
M. Kidera, T. Aihara, Y. Higurashi, M. Kase, T.
Nakagawa, and Y. Yano: “Intense heavy ion beam
production from RIKEN ECRISs”, 17th International Conference on Cyclotrons and Their Applications (Cyclotrons 2004), Tokyo, Oct. (2004).
H. Hasebe, M. Kase, H. Ryuto, and Y. Yano:“Long-lived carbon stripper foils for intense heavyion beams”, 17th International Conference on Cyclotrons and Their Applications (Cyclotrons 2004),
Tokyo, Oct. (2004).
H. Okuno, N. Fukunishi, A. Goto, K. Ikegami, M.
Nagase, J. Ohnishi, T. Tominaka, Y. Yano, and S.
Yokouchi: “Magnets for the RIKEN Superconducting Ring Cyclotron”, 17th International Conference
on Cyclotrons and Their Applications (Cyclotrons
2004), Tokyo, Oct. (2004).
M. Kase, M. Fujimaki, N. Fukunishi, A. Goto, Y.
Higurashi, E. Ikezawa, N. Inabe, O. Kamigaito, M.
Kidera, S. Kohara, M. Komiyama, M. Nagase, T.
Nakagawa, H. Okuno, H. Ryuto, M. Wakasugi, Y.
Yano, S. Yokouchi, and Y. Ohshiro: “Present status of the RIKEN Ring Cyclotron”, 17th International Conference on Cyclotrons and Their Applications (Cyclotrons 2004), Tokyo, Oct. (2004).
Y. Yano: “RI beam factory project at RIKEN”, 17th
International Conference on Cyclotrons and Their
Applications (Cyclotrons 2004), Tokyo, Oct. (2004).
T. Tanabe, T. Emoto, M. Kase, K. Kumagai, T.
Masuoka, and K. Yoshida: “RIKEN RI-Beam Factory power supply control system”, 17th International Conference on Cyclotrons and Their Applications (Cyclotrons 2004), Tokyo, Oct. (2004).
H. Ryuto, N. Fukunishi, A. Goto, H. Hasebe, N. Inabe,
M. Kase, Y. Yano, and S. Yokouchi: “Rotating carbon disk stripper for intense heavy-ion beams”, 17th
International Conference on Cyclotrons and Their
Applications (Cyclotrons 2004), Tokyo, Oct. (2004).
K. Hidume, D. Ueyama, R. Kuroda, S. Minamiguchi,
A. Oshima, Y. Hama, M. Washio, J. Urakawa, H.
Hayano, S. Kashiwagi, and K. Ushida: “Soft Xray generation using inverse Compton scattering at
Waseda University”, 47th Symposium on Radiation
Chemistry, (Japanese Society of Radiation Chemistry), Sapporo, Oct. (2004).

A. Goto: “Status of the RIKEN RI Beam Facotry
Project”, Indian Particle Accelerator Conference
2005 (InPAC-2005), (Variable Energy Cyclotron
Center and Department of Atomic Energy), Koltaka,
India, Mar. (2005).
P. Bakule and Y. Matsuda: “Generation of slow
muons by laser ionization of muonium”, International Workshop on Muon Science Instrumentation(MSI-05), (JSP Core-to-Core Program on Development of Advanced Muon and Positron Beam),
Tsukuba, Mar. (2005).
H. Ryuto, T. Abe, N. Fukunishi, M. Kase, and Y.
Yano: “Heavy-ion beam irradiation system for biological samples in RIKEN”, International Symposium on Novel Techniques in Nano-Biology 2005
(ISNB05), (Biology Research Center of Industrial
Accelerator, Dongshin University and others), Jeollanamdo, Korea, Apr. (2005).
H. Ryuto, N. Fukunishi, A. Goto, H. Hasebe, N.
Inabe, O. Kamigaito, M. Kase, Y. Yano, and S.
Yokouchi: “Charge strippers in the RIKEN RIbeam factory”, 2005 Particle Accelerator Conference (PAC05), (Oak Ridge National Laboratory
and Thomas Jeﬀerson National Accelerator Facility), Knoxville, USA, May (2005).
H. Ryuto, N. Fukunishi, H. Hasebe, S. Yokouchi, A.
Goto, M. Kase, and Y. Yano: “Preperation of charge
strippers for the RIKEN RI-beam factory”, Workshop on Accelerator Operations 2005 (WAO2005),(Fermi National Accelerator Laboratory), Bloomingdale, USA, May (2005).
Y. Matsuda: “Generation of low energy muon withlaser resonant ionization of muonium atoms”, 7thInternational Workshop on Neutrino Factories andSuperbeams (NuFact 05), (Laboratori Nazionali diFrascati), Rome, Italy, June (2005).
E. Ikezawa, N. Inabe, T. Kageyama, N. Fukunishi,
M. Kase, M. Fujimaki, T. Fujinawa, A. Goto, H.
Hasebe, Y. Higurashi, O. Kamigaito, M. Kidera, T.
Nakagawa, S. Kohara, N. Sakamoto, M. Komiyama,
M. Nagase, M. Wakasugi, T. Watanabe, H. Okuno,
H. Ryuto, S. Yokouchi, A. Yoneda, Y. Ohshiro, andY. Yano: “Present status of accelerators in RIKEN
accelerator research Facility”, 2nd Annual Meetingof Particle Accelerator Society of Japan/30th Linear
Accelerator Meeting in Japan, Tosu, July (2005).
Y. Yamazaki: “Nanodots formation with slow highly
charged ions”, 17th International Conference on IonSurface Interactions (ISI-2005), (Moscow Aviation
Institute), Zvenigorod, Russia, Aug. (2005).
M. Kidera, T. Nakagawa, K. Takahashi, S. Enomoto,
K. Enomoto, M. Fujimaki, E. Ikezawa, O.
Kamigaito, M. Kase, A. Goto, and Y. Yano: “Improvement of RIKEN ECRIS-AMS”, 11th International Conference on Ion Sources (ICIS05), Caen,
France, Sept. (2005).
T. Watanabe, M. Kase, Y. Sasaki, S. Watanabe, T.

Ikeda, T. Kawaguchi, and Y. Yano: “Current andposition beam monitor with HTS SQUIDs and HTS
magnetic shield for the RIKEN Ring Cyclotron”, 7thEuropean Conference on Applied Superconductivity(EUCAS ’05), (Vienna University of Technology),
Vienna, Austria, Sept. (2005).
T. Watanabe, M. Kase, S. Watanabe, T. Ikeda, T.
Kawaguchi, and Y. Yano: “Current and Position
Monitor with HTS SQUIDs and HTS Magnetic
Shield for RRC”, Seminar at Paul Scherrer Institute,Villigen, Switzerland, Sept. (2005).
T. Watanabe, M. Kase, Y. Sasaki, S. Watanabe,
T. Kawaguchi, and Y. Yano: “Measurement andanalysis system using HTS SQUID for heavy ion
beam”, 62nd workshop on Forum of Superconductivity Science and Technology, (The Society of NonTraditional Technology), Tokyo, Nov. (2005).

2.

Nuclear physics and nuclear instrumentation

T. Suda: “Electron scattering oﬀ unstable nuclei”, International Workshop 32nd on Gross Properties of
Nuclei and Nuclear Excitations, (GSI), Hirschegg,
Austria, Jan. (2004).
S. Sugimoto, K. Ikeda, and H. Toki: “Charge- andparity-projected Hartree-Fock method with deformation”, 59th Annual Meeting of the Physical Society of Japan, Fukuoka, Mar. (2004).
K. Ishida, K. Nagamine, T. Matsuzaki, N. Kawamura,
Y. Matsuda, M. Iwasaki, H. Imao, M. Kato, H.
Sugai, M. Tanase, S. Nakamura, K. Kudo, N.
Takeda, and G. H. Eaton: “Magnetic ﬁeld eﬀect inmuon catalyzed fusion in D-T mixtures”, Present
status and future of muon science at RIKEN-RAL
Muon Facility, Wako, May (2004).
S. Sugimoto, K. Ikeda, and H. Toki: “Charge- andparity-projected Hatree-Fock method for the strong
tensor correlation and its application to the alpha particle”, International Nuclear Physics Conference (INPC2004), (Chalmers University of Technology and Goteborgs University), Goteborg, Sweden,
June–July (2004).
K. Sekiguchi, H. Sakai, H. Okamura, A. Tamii, T.
Uesaka, K. Suda, N. Sakamoto, M. Hatano, T.
Wakasa, Y. Sato, T. Ohnishi, K. Yako, S. Sakoda,
H. Kato, Y. Maeda, J. Nishikawa, T. Saito, N.
Uchigashima, N. N. Kalantar, and K. Ermisch:“Deuteron-Proton Scattering at Intermediate Energies and Three-Nucleon Forces”, International Nuclear Physics Conference (INPC2004), (Chalmers
University of Technology and Goteborgs University),
Goteborg, Sweden, June–July (2004).
H. Ueno, K. Asahi, D. Kameda, H. Miyoshi, A.
Yoshimi, K. Shimada, G. Kato, S. Emori, G.
Kijima, M. Tsukui, H. Watanabe, T. Haseyama,
Y. Kobayashi, and M. Ishihara: “Spin-polarizedradioactive-isotope beams and the measurement of285

nuclear moments”, International Nuclear Physics
Conference (INPC2004), (Chalmers University ofTechnology and Goteborg University), Goteborg,
Sweden, June–July (2004).
T. Yamazaki: “Two-particle wave function in fourdimensional Ising model”, LATTICE 2004: 22ndInternational Symposium on Lattice Field Theory,(Fermi National Accelerator Laboratory), Batavia,
USA, June (2004).
Y. Motizuki: “Research on the r-process nucleosynthesis in the coming decade”, RIBF-UEC/RIKEN
Workshop on Physics of Unstable Nuclei: Past
Decade and the Future, (RIBF-UEC), Wako, June
(2004).
P. Strasser, K. Nagamine, T. Matsuzaki, K. Ishida,
Y. Matsuda, and M. Iwasaki: “Muonic atoms ofradioactive nuclei”, 6th International Workshop on
Neutrino Factories and Superbeams (NuFact 04),
Osaka, July–Aug. (2004).
Y. Motizuki: “The r-process nucleosynthesis in a
multi-dimensional supernova model”, 8th International Symposium on Nuclei in the Cosmos (NIC8),(TRIUMF), Vancouver, Canada, July (2004).
H. Ueno, A. Yoshimi, H. Watanabe, T. Haseyama, Y.
Kobayashi, K. Asahi, D. Kameda, H. Miyoshi, K.
Shimada, G. Kato, S. Emori, G. Kijima, M. Tsukui,and H. Ogawa: “Nuclear-moment measurements oflight neutron-rich nuclei”, International Symposium
on Exotic Nuclei (EXON 2004), (JINR and RIKEN,
and others), St. Petersburg, Russia, July (2004).
M. Wada: “The Universal Slow-RI-beem Facility at
RIKEN RIBF”, International Symposium on Exotic
Nuclei (EXON 2004), (JINR and RIKEN, and others), St. Petersburg, Russia, July (2004).
A. Yoshimi, K. Asahi, S. Emori, and M. Tsukui: “Nuclear spin maser oscillation of 129Xe by means of
optical-detection feedback”, 13th International Conference on Hyperﬁne Interactions & 17th International Symposium on Nuclear Quadrupole Interaction, (Rheinische Friedrich-Wilhelms-Universitat
Bonn and others), Bonn, Germany, Aug. (2004).
T. Saito, H. Sakai, T. Ikeda, K. Itoh, T. Uesaka, T.
Kawabata, H. Kuboki, M. Sasano, Y. Sato, K. Suda,
K. Sekiguchi, A. Tamii, Y. Maeda, N. Matsui, andK. Yako: “Experimental test of Bell’s inequality via
the 1 H(d, 2 He)n reaction”, 19th European Conference on Few-Body Problems in Physics, Groningen,
The Netherlands, Aug. (2004).
K. Sekiguchi: “Exploring Three Nucleon Forces
through dp Scattering at Intermediate Energies”,
19th European Conference on Few-Body Problems in Physics, Groningen, The Netherlands, Aug.
(2004).
T. Yamazaki, S. Aoki, M. Fukugita, K. Ishikawa, N.
Ishizuka, Y. Iwasaki, K. Kanaya, T. Kaneko, Y.
Kuramashi, M. Okawa, A. Ukawa, and T. Yoshie:“I = 2 S-wave pion scattering phase shift with two

286

ﬂavor fullQCD”, Meeting of the Division of Particles and Fields of the American Physical Society(DPF2004), Riverside, USA, Aug. (2004).
S. Sugimoto, K. Ikeda, and H. Toki: “Study of 8 Be
with the charge- and parity-projected Hartree-Fockmethod”, 2004 Autumn Meeting of the Physical Society of Japan, Aomori and Kochi, Sept. (2004).
T. Yamazaki: “Two-particle wave function in four dimensional Ising model”, 2004 Autumn Meeting of
the Physical Society of Japan, Aomori and Kochi,
Sept. (2004).
M. Takashina, H. Sakuragi, and Y. Iseri: “Eﬀect
of halo structure on 11 Be+12 C elastic scattering”,
4th International Conference on Exotic Nuclei andAtomic Masses (ENAM 04), (Physics Division, Oak
Ridge National Laboratory), Pine Mountain, USA,
Sept. (2004).
A. Yoshimi, K. Asahi, S. Emori, M. Tsukui, and S.
Oshima: “Low-frequency nuclear spin maser andsearch for atomic EDM of 129Xe”, 16th International Spin Physics Symposium (SPIN 2004), (Istituto Nazionale di Fisica Nucleare (INFN)), Trieste,
Italy, Oct. (2004).
A. Yoshimi, K. Asahi, S. Emori, M. Tsukui, and S.
Oshima: “Spin maser of 129Xe nuclei at low magnetic ﬁeld by optical spin detection”, International
Conference on Laser Probing (LAP2004), (Argonne
National Laboratory), Argonne, USA, Oct. (2004).
T. Yamazaki, S. Aoki, M. Fukugita, K. Ishikawa, N.
Ishizuka, Y. Iwasaki, K. Kanaya, T. Kaneko, Y.
Kuramashi, M. Okawa, A. Ukawa, and T. Yoshie:“I = 2 S-wave pion scattering phase shift with twoﬂavor full QCD”, Workshop on the Physics Programme of the RBRC and UKQCD QCDOC Machines, Upton, USA, 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: “Study of the stellar 22 Mg(p,γ)23 Al reaction with Coulomb dissociation method”, 21th
Meeting between Astrophysicists and Nuclear Physicists, (Universite Libre de Bruxelles), Brussels, Belgium, Dec. (2004).
T. Matsuzaki: “Muon catalyzed t-t fusion and the related problems”, Workshop on “Recent developmentof few body physic and the prospect”, (RCNP),
Ibaraki, Dec. (2004).
D. Nagae, K. Asahi, H. Miyoshi, K. Shimada, A.
Yoshimi, M. Uchida, H. Ueno, J. Murata, W. D.

Schmidt-Ott, Y. Kobayashi, T. Haseyama, D.
Kameda, G. Kato, S. Emori, G. Kijima, S. Oshima,
T. Arai, and M. Takemura: “Development of
stopping, extraction and neutralization system foratomic beam resonance method”, 1st International
Symposium on Nanometer-scale Quantum Physics(nanoPHYS’05), Tokyo, Jan. (2005).
N. D. Dang: “Giant resonances at zero and ﬁnite temperature”, International Conference on the Interface
between Nuclear Structure, Astrophysics and Reactions (NUSTAR ’05), (University of Surrey), Guildford, UK, Jan. (2005).
M. Hoshino, T. Kambara, Y. Kanai, R. Schuch, andY. Yamazaki: “Multiple-electron processes in acollision of slow highly charged ion with atom”,
RIKEN Symposium on Studies on Condensed Matter Physics, Atomic Physics, Hyperﬁne Interactions
and Biomedical Sciences using RIKEN Accelerators,
Wako, Jan. (2005).
Y. Motizuki: “The r-process nucleosynthesis in corecollapse supernova explosions induced by anisotropic
neutrino radiation”, 2005 Spring Annual Meeting of
Astronomical Society of Japan, Hino, Mar. (2005).
H. Madokoro: “Two-Dimensional Numerical Simulation of Core-Collapse Supernovae With Anisotropic
Neutrino Radiation”, 2005 Spring Annual Meetingof Astronomical Society of Japan, Hino, Mar. (2005).
N. D. Dang: “Giant resonances at zero and ﬁnite temperatures”, 229th ACS National Meeting, (American Chemical Society), San Diego, USA, Mar.
(2005).
N. Aoi: “γ-ray spectroscopy of neutron rich N =40∼50 nuclei with proton inelastic scattering.”, 60th
Annual Meeting of Physical Society of Japan, Noda,
Mar. (2005).
A. Kohama, K. Iida, and K. Oyamatsu: “Energy
dependence of black-sphere radius”, 60th Annual
Meeting of Physical Society of Japan, Noda, Mar.
(2005).
Y. Motizuki, H. Madokoro, T. Tachibana, and S.
Goriely: “The r-process nucleosynthesis in twodimensional core-collapse supernova explosions”,
60th Annual Meeting of Physical Society of Japan,
Noda, Mar. (2005).
H. Madokoro: “Two-Dimensional Numerical Simulation of Core-Collapse Supernovae With Anisotropic
Neutrino Radiation”, 60th Annual Meeting of Physical Society of Japan, Noda, Mar. (2005).
N. D. Dang: “Particle-number conservation within
the self-consistent RPA”, Cyclotron Institute Colloquium, (Texas A&M University), College Station,
USA, Mar. (2005).
T. Matsuzaki: “An in-situ tritium gas-handling system for muon catalyzed fusion research at the
RIKEN-RAL Muon Facility”, International Workshop on Muon Science Instrumentation (MSI-05),(JSP Core-to-Core Program on Development of Ad-

vanced Muon and Positron Beam), Tukuba, Mar.
(2005).
K. Ishida: “Muon catalyzed fusion experiment withhigh-intensity pulsed muon beams”, International
Workshop on Muon Science Instrumentation (MSI05), (JSP Core-to-Core Program on Developmentof Advanced Muon and Positron Beam), Tsukuba,Mar. (2005).
Y. Motizuki, K. Takahashi, A. Bamba, K. Makishima,
Y. Yano, H. Motoyama, M. Igarashi, K. Kamiyama,
K. Suzuki, and H. Niko: “Supernova legacy investigated with Antarctic ice core drilled at Dome-Fuji
station”, NIPR Symposium on Frontiers of Physics,
Chemistry, and Biology in Antarctic Ice Studies,(National Institute of Polar Research), Tokyo, Mar.
(2005).
Y. Motizuki: “Research activities of RIKEN in relation
with the r-process nucleosynthesis”, Seminar at Institut d’Astronomie et d’Astrophysique, Universite
Libre de Bruxelles, Brussels, Belgium, Mar. (2005).
Y. Motizuki: “The r-process nucleosynthesis in a twodimensional core-collapse supernova model”, Theoretical Nuclear Physics ‘Donshu’ Conference, (KEKIPNS), Tsukuba, Mar. (2005).
Y. Motizuki: “How to make a good presentation at
an international conference II”, RIBF NAP (Nuclear
Astrophysics Project) Seminar, Wako, May (2005).
A. Kohama, K. Iida, and K. Oyamatsu: “Looking at
nuclei in the black sphere picture”, RIKEN RIBF
International Workshop on “Collective motions inunstable nuclei: experiments vs. theories”, Wako,
May (2005).
M. Yamagami: “Spatially extended coherence inducedby pairing correlations in neutron drip line nuclei”,
RIKEN RIBF International Workshop on “Collective motions in unstable nuclei: experiments vs. theories”, Wako, May (2005).
M. Wada: “Slow RI-beams using RF ion guide andSpace-charge eﬀect in the gas cell”, Radioactive Ion
Beam-Targets and Ion Sources, (Oak Ridge National
Laboratory), Oak Ridge, USA, May (2005).
M. Yamagami: “Novel coordinate space representation for deformed loosely-bound nuclei”, YITP
Workshop on New Developments in Nuclear SelfConsistent Mean-Field Theories (MF05), Kyoto,
May–June (2005).
K. Ishida: “Muon catalyzed fusion”, 7th International Workshop on Neutrino Factories and Superbeams (NuFact 05), (Laboratori Nazionali di Frascati), Rome, Italy, June (2005).
M. Takashina: “16 C inelastic scattering studied withmicroscopic coupled-channels method”, Direct Reactions with Exotic Beams (DREB2005), (Michigan
State University), East Lansing, USA, June (2005).
S. Takeuchi, N. Aoi, H. Baba, T. Kubo, T. Fukui,
Y. Hashimoto, K. Ieki, N. Imai, H. Iwasaki, S.
Kanno, Y. Kondo, K. Kurita, T. Minemura, T.

287

Motobayashi, T. Nakabayashi, T. Nakamura, T.
Okumura, T. Onishi, S. Ota, H. Sakurai, S.
Shimoura, R. Sugo, D. Suzuki, H. Suzuki, M.
Suzuki, E. Takeshita, M. Tamaki, K. Tanaka, Y.
Togano, and K. Yamada: “Proton inelastic scattering on 34 Si and 32 Mg”, Direct Reactions with Exotic
Beams (DREB2005), (Michigan State University),
East Lansing, USA, June (2005).
T. Matsumoto: “The method of continuum-discretizedcoupled-channels for four-body breakup reactions”,
Direct Reactions with Exotic Beams (DREB2005),(Michigan State University), East Lansing, USA,
June (2005).
K. Ishida: “Muon catalyzed fusion”, Workshop on
Neutrino Factories and Superbeams (NuFact-J 05),
(Tokyo institute of technology), Tokyo, June (2005).
K. Asahi, A. Yoshimi, M. Uchida, S. Emori, and S.
Oshima: “Nuclear spin maser with novel masing
mechanism and search for atomic EDM in 129 Xe”,
5th Circum-Pan-Paciﬁc Symposium on High Energy
Spin Physics (SPIN 2005), (Tokyo Institute of Technology), Tokyo, July (2005).
Y. Motizuki: “History of supernovae and solar activity investigated with Antarctic ice”, NIES (National Institute for Environmental Studies) Seminar,
Tsukuba, July (2005).
Y. Ishida, M. Wada, Y. Yamazaki, and H. Wollnik:“Compact time-of-ﬂight mass spectrometer of highresolving power: MR-TOF”, 30th Annual Meetingof the Society for Atomic Collision Reserach, Wako,
Aug. (2005).
N. Aoi: “Exotic structure of unstable nuclei revealed
through a g-ray spectroscopy technique”, 4th CNS
International Summer School (CISS05), Wako, Aug.
(2005).
M. Takashina, E. K. Yoshiko, and Y. Sakuragi:“16 C inelastic scattering studied with microscopic
coupled-channels method”, 2nd Joint Meeting of
the Nuclear Physics Divisions of the APS and JPS(Hawaii 2005), Maui, USA, Sept. (2005).
T. Egami, K. Ogata, T. Matsumoto, E. Hiyama,
Y. Iseri, M. Kamimura, and M. Yahiro: “Fourbody CDCC analysis of 6 He+209 Bi scattering near
Coulomb barrier energies”, 2nd Joint Meeting of
the Nuclear Physics Divisions of the APS and JPS(Hawaii 2005), Maui, USA, Sept. (2005).
H. Ueno: “Ground-state nuclear moments of neutronrich p- and sd-shell nuclei”, 2nd Joint Meeting of
the Nuclear Physics Divisions of the APS and JPS(Hawaii 2005), Maui, USA, Sept. (2005).
E. Takeshita, N. Aoi, S. Ota, S. Takeuchi, H. Suzuki,
H. Baba, S. Bishop, T. Fukui, Y. Hashimoto, H.
Ong, E. Ideguchi, K. Ieki, N. Imai, H. Iwasaki, S.
Kanno, Y. Kondo, T. Kubo, K. Kurita, K. Kusaka,
T. Minemura, T. Motobayashi, T. Nakabayashi, T.
Nakamura, T. Nakao, M. Niikura, T. Okumura, T.
Onishi, H. Sakurai, S. Shimoura, R. Sugo, D. Suzuki,

288

M. Suzuki, M. Tamaki, K. Tanaka, Y. Togano, andK. Yamada: “Inelastic proton scattering on the neutron rich Cr isotopes”, 2nd Joint Meeting of the Nuclear Physics Divisions of the APS and JPS (Hawaii2005), Maui, USA, Sept. (2005).
A. Yoshimi, K. Asahi, M. Uchida, and S. Oshima:“Nuclear spin maser at low frequency and atomic
EDM of 129 Xe”, 2nd Joint Meeting of the Nuclear
Physics Divisions of the APS and JPS (Hawaii 2005),
Maui, USA, Sept. (2005).
M. Yamagami: “Pairing correlations in deformed nuclei close to the neutron drip line”, 2nd Joint Meeting of the Nuclear Physics Divisions of the APS and
JPS (Hawaii 2005), Maui, USA, Sept. (2005).
I. Nakagawa: “Polarization Measurement of 100 GeV
Proton Beams at RHIC with CNI pC polarimeter”,
2nd Joint Meeting of the Nuclear Physics Divisionsof the APS and JPS (Hawaii 2005), Maui, USA,
Sept. (2005).
S. Takeuchi, N. Aoi, H. Baba, T. Fukui, Y. Hashimoto,K. Ieki, N. Imai, H. Iwasaki, S. Kanno, Y. Kondo,
K. Kurita, T. Minemura, T. Motobayashi, T.
Nakabayashi, T. Nakamura, T. Okumura, T. Onishi,
S. Ota, H. Sakurai, S. Shimoura, R. Sugo, D. Suzuki,
H. Suzuki, M. Suzuki, E. Takeshita, M. Tamaki, K.
Tanaka, Y. Togano, and K. Yamada: “Proton inelastic scattering on 34 Si and 32 Mg”, 2nd Joint Meetingof the Nuclear Physics Divisions of the APS and JPS(Hawaii 2005), Maui, USA, Sept. (2005).
M. Yamagami: “Spatially extended coherence inducedby pairing correlation in low-frequency vibrational
excitation of neutron drip line nuclei”, 2nd Joint
Meeting of the Nuclear Physics Divisions of the APS
and JPS (Hawaii 2005), Maui, USA, Sept. (2005).
Y. Motizuki: “Observation project of the nonthermal
universe: from the world of the elements to that of
nuclides”, 6th Symposium on High Energy Astrophysics Association in Japan, Tokyo, Sept. (2005).
Y. Motizuki: “X-or gamma-rays from supernovae inglacial ice?”, International Workshop on Astronomy
with Radioactivities V: From Gamma Rays to Stardust, (Clemson University), Clemson, USA, Sept.
(2005).
M. Yamagami: “Continuum eﬀects for many-body correlations in nuclei close to the neutron drip line”,
Nuclear Structure Near the Limits of Stability (INT05-3), (Institute for Nuclear Theory), Seattle, USA,
Sept. (2005).
M. Yamagami: “Continuum eﬀects for many-body correlations in nuclei close to the neutron drip line”,
RIKEN RIBF Mini-Workshop: Pairing Correlationsin Unstable Nuclei, Wako, Sept. (2005).
M. Yamagami: “Continuum eﬀects for many-body correlations in nuclei close to the neutron drip line”,
Tensor force and many-body correlations in nuclei,(Yukawa Institute for Theoretical Physics, Kyoto
University), Kyoto, Sept. (2005).

Y. Motizuki: “History of supernovae and solar activity
investigated with Antarctic ice core: Can we perform
a related experiment at SPring-8?”, 147th SPring-8
Seminar, Harima, Oct. (2005).
Y. Motizuki, H. Madokoro, T. Tachibana, S. Goriely,
and K. Takahashi: “The r-process nucleosynthesis in
a 2-D supernova model: Multi-dimensional eﬀect”,
2005 Fall Annual Meeting of Astronomy Society ofJapan, Sapporo, Oct. (2005).
H. Madokoro: “Two-Dimensional Numerical Simulation of Core-Collapse Supernovae Induced by
Anisotropic Neutrino Radiation”, 2005 Fall Annual
Meeting of Astronomy Society of Japan, Sapporo,Oct. (2005).
H. Ueno: “Production of spin-oriented unstable nuclei via the projectile-fragmentation reaction”, 11th
International Workshop on Polarized Sources andTargets (PST05), (RIKEN and CNS), Tokyo, Nov.
(2005).
Y. Motizuki and H. Madokoro: “The r-process nucleosynthesis in a 2-Dimensional supernova model”,
International Symposium on Origin of Matter and
Evolution of Galaxies (OMEG05)): New Horizon of
Nuclear Astrophysics and Cosmology, Tokyo, Nov.
(2005).
H. Ueno: “RI spin laboratory project”, RIKEN RI
Beam Factory Technical Advisory Committee Meeting, Wako, Nov. (2005).
T. Matsumoto, T. Egami, E. Hiyama, K. Ogata,
Y. Iseri, M. Kamimura, and M. Yahiro: “Fourbody CDCC analyses of 6 He+12 C and 6 He+209 Bi
scattering”, RIKEN-CNS RIBF International Workshop “Correlation and Condensation: New Featuresin Loosely Bound and Unbound Nuclear States”,
Wako, Dec. (2005).
H. Ueno: “Nuclear moments of neutron-rich Al
isotope”, RIKEN-CNS RIBF International Workshop “Correlation and Condensation: New Featuresin Loosely Bound and Unbound Nuclear States”,
Wako, Dec. (2005).
M. Yamagami: “Pairing correlation in deformed
neutron-rich nuclei”, RIKEN-CNS RIBF International Workshop “Correlation and Condensation:
New Features in Loosely Bound and Unbound Nuclear States”, Wako, Dec. (2005).
M. Yamagami: “Continuum eﬀects for many-bodycorrelations in medium mass neutron-rich nuclei”,
YITP Workshop on Binding Mechanism and New
Dynamics in Weakly Bound Systems, (Yukawa Institute for Theoretical Physics, Kyoto University),
Kyoto, Dec. (2005).
M. Takashina: “Analysis of 12 C, 16 O(α,α’) reaction using BEC wave function”, YITP Workshop on Binding mechanism and new dynamics in weakly boundsystems, (Yukawa Institute of Theoretical Physics,
Kyoto University), Kyoto, Dec. (2005).

3.

Atomic and solid-state physics

S. Ohira-Kawamura, M. Tamura, R. Kato, I.
Watanabe, and M. Iwasaki: “µSR study on magnetic property of [Pd(dmit)2 ] salts”, 5th International Symposium on Crystalline Organic Metals, Superconductors and Magnets (ISCOM’ 2003),
Port-Bourgenay, France, Sept. (2003).
M. Hoshino, Y. Kanai, M. Kitajima, Y. Nakai, Y.
Yamazaki, and H. Tanaka: “The study of doubleelectron catpure processes in slow C4+ -He collisions”, Genshi/Bunshi hannou so katei ni okeru ryuushi soukan, Okazaki, June (2004).
Y. Fukuyama, Y. Moriwaki, and Y. Matsuo: “Stabilization of Ba+∗ -He exciplex below the critical temperature at 3.3 K: Formation and dissociation ofBa+∗ -He”, 1st Atomic, Molecular and Optical Science Forum, Tokyo, July (2004).
H. Ueno, K. Asahi, W. Sato, A. Yoshimi, H. Watanabe,
Y. Kobayashi, H. Miyoshi, J. Murata, K. Shimada,D. Kameda, G. Kato, S. Emori, and T. Haseyama:“Study on the transient ﬁeld at high velocities”,
13th International Conference on Hyperﬁne Interactions & 17th International Symposium on Nuclear Quadrupole Interaction, (University of Bonn),
Bonn, Germany, Aug. (2004).
M. Hoshino, Y. Kanai, Y. Yamazaki, T. Kambara, and
R. Schuch: “The study of multiple electron processes
in close collisions of slow Ne2+ with Ar”, 29th Annual Meeting of the Society for Atomic Collision Research, Sendai, Aug. (2004).
M. Hoshino, T. Kambara, Y. Kanai, Y. Yamazaki, and
R. Schuch: “Multi-electron Processes in close, single
collisions between slow Ne2+ and Ar”, 2004 Autumn
Meeting of the Physical Society of Japan, Aomori
and Kochi, Sept. (2004).
Y. Miyamoto, M. Hoshino, Y. Kanai, Y. Nakai, M.
Kitajima, Y. Yamazaki, and H. Tanaka: “Single and double electron capture processes for slow
highly charged ion (N5+ )-He collisions”, 2004 Autumn Meeting of the Physical Society of Japan, Aomori and Kochi, Sept. (2004).
L. Pichl, R. Suzuki, M. Hoshino, M. Kimura, Y. Li,
and R. J. Buenker: “Theoretical study of double
electron capture in collisions of C4+ with He”, 2004
Autumn Meeting of the Physical Society of Japan,
Aomori and Kochi, Sept. (2004).
Y. Iwai, Y. Nakai, Y. Kanai, T. Ikeda, M. Hoshino,
K. Nishio, H. Masuda, and Y. Yamazaki: “Coincidence measurements of L X-rays and ﬁnal charge
state for Ar13+ ions passing through Ni microcapillaries”, 15th International Workshop on Inelastic
Ion-Surface Collisions (IISC-15), (The Japan Society of Applied Physics), Ise, Oct. (2004).
Y. Matsuo: “Laser spectroscopy and producing spinpolarization of atoms with unstable nuclei trapped insuperﬂuid helium”, RIKEN Symposium on Research289

Projects Dedicated to RIPS in the RIBF Conﬁguration, Wako, Oct. (2004).
Y. Fukuyama, Y. Moriwaki, and Y. Matsuo: “Formation and dissociation of Ba+∗ -He exciplex incold He gas: characteristic behavior of cold collision process”, Symposium on Physics and Chemistry of Atoms, Molecules and Ions in Quantum Condensed Phases, (Advanced Science Research Centerof JAERI), Tokai-mura, Ibaraki Pref., Dec. (2004).
Y. Matsuo, Y. Fukuyama, T. Kobayashi, T. Furukawa,H. Izumi, Y. Arakawa, I. Wakabayashi, K. Kawai, S.
Morinobu, T. Shimoda, and A. Hatakeyama: “Longelectric spin relaxation time of Cs atoms in superﬂuid helium: towards laser spectroscopy of atoms
with unstable nuclei”, Symposium on Physics andChemistry of Atoms, Molecules and Ions in Quantum Condensed Phases, (Advanced Science Research Center of JAERI), Tokai-mura, Ibaraki Pref.,Dec. (2004).
Y. Nakai: “Resonant Coherent Excitation of Fast
Highly Charged Ions”, RIKEN Symposium on 9th
Studies on Condensed Matter Physics, Atomic
Physics, Hyperﬁne Interactions and Biomedical
Sciences Using RIKEN Accelerators, Wako, Jan.
(2005).
Y. Fukuyama, Y. Moriwaki, and Y. Matsuo: “Laserinduced ﬂuorescence spectra of Ba+∗ -He exciplexes
produced in cold He gas”, Symposium on reaction
mechanism cross-over by resonance control, (ISAS,
JAXA), Sagamihara, Jan. (2005).
I. Shimamura and A. Igarashi: “Resonance analysis interms of the time-delay matrix: the eﬀect of polesof the time-independent S matrix”, Workshop on
Atomic and Molecular Processes in Space, (ISAS,
JAXA), Sagamihara, Jan. (2005).
Y. Yamazaki: “High senstive detection of surfaceadsorbed hydrogen atoms with slow highly chargedions”, 52nd Spring Meeting 2005 of The Japan
Society of Applied Physics and Related Societies,
Saitama, Mar.–Apr. (2005).
Y. Yoshida, Y. Kobayashi, A. Yoshida, H. Ueno,
K. Hayakawa, K. Yukihira, F. Ambe, and F.
Shimura: “In-situ observation of the diﬀusion process of Fe atoms in Si matrix by 57Mn/57Fe in-beammössbauer spectroscopy”, 60th Annual Meeting ofPhysical Society of Japan, Noda, Mar. (2005).
Y. Matsuo, N. Yonekura, T. Kobayashi, Y. Fukuyama,
and T. Nakajima: “Production of highly spinpolarized ions and electrons by resonant photoionization of Sr atoms to the 4s5d autoionizing states”,
60th Annual Meeting of Physical Society of Japan,
Noda, Mar. (2005).
Y. Yamazaki: “Nanodots formation with slow highly
charged ions”, Physics at EBIT and Advanced Research Light Sources (PEARL 2005), (Fudan University and Lund University), Hainan, China, Mar.
(2005).

290

Y. Yamazaki: “New Techniques for Trapping Antiprotons, Positrons, and Antihydrogen Atoms”, International Conference on Low Energy Antiproton
Physics (LEAP’05), Bonn, Germany, May (2005).
T. Furukawa, Y. Matsuo, A. Hatakeyama, Y.
Fukuyama, T. Kobayashi, H. Izumi, and T.
Shimoda: “Electron spin depolarization of Cs atoms
in superﬂuid helium”, 2nd Atomic, Molecular andOptical Science Forum, Wako, June (2005).
Y. Kanai, M. Hoshino, T. Kambara, Y. Yamazaki,
R. Hellhammer, and N. Stolterfoht: “Two dimensional images of ions transmitted through insulator capillaries under beam guiding conditions”, 24th
International Conference on Photonic, Electronicand Atomic Collisions (ICPEAC 2005), Rosario, Argentina, July (2005).
Y. Fukuyama, Y. Moriwaki, and Y. Matsuo: “Cold
Collision of Ba+∗ with He: Formation, Dissociation and Vibrational Relaxation of Ba+∗ -He exciplexes”, International Quantum Electronics Conference 2005 and the Paciﬁc Rim Conference on Lasers
and Electro-Optics 2005 (IQEC/CLEO-PR 2005),(Science Council of Japan and others), Tokyo, July
(2005).
T. Furukawa, Y. Matsuo, A. Hatakeyama, Y.
Fukuyama, T. Kobayashi, and T. Shimoda: “Long
Electronic Spin Relaxation Time of Cs Atoms in Superﬂuid Helium”, International Quantum Electronics Conference 2005 and the Paciﬁc Rim Conferenceon Lasers and Electro-Optics 2005 (IQEC/CLEOPR 2005), (Science Council of Japan and others),
Tokyo, July (2005).
Y. Matsuo, Y. Fukuyama, and Y. Moriwaki: “Temperature and Pressure Control of Cold Helium Gas
above Liquid Helium for Laser Spectroscopy ofAtoms and Molecules in Helium Gas of 3-30 K”,
24th International Conference on Low Temperature
Physics (LT24), (Department of Physics and University of Florida), Orlando, USA, Aug. (2005).
Y. Kanai, M. Hoshino, T. Ikeda, T. Kambara, Y.
Yamazaki, R. Hellhammer, and N. Stolterfoht: “Ionbeam guide eﬀect of insulator capillaries”, 30th Annual Meeting of the Society for Atomic Collision Reserach, Wako, Aug. (2005).
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: “Study of the resonant
electron capture and decay processes for N ions using
microcapillary targets”, 30th Annual Meeting of theSociety for Atomic Collision Reserach, Wako, Aug.
(2005).
S. Tsutsui, J. Uemura, H. Kobayashi, T. Tazaki, S.
Nasu, Y. Kobayashi, Y. Yoda, H. Onodera, H.
Sugiwara, D. T. Matsuda, D. Kikuchi, H. Sato, C.
Sekine, and I. Shirotani: “Elastic properties of ﬁlledskutterudite compounds probed by Mössbauer nuclei”, International Conference on the Applications

of the Mössbauer Eﬀect (ICAME2005), Montpellier,France, Sept. (2005).
K. Kubo, Y. Kobayashi, H. Nonaka, Y. Yamada, Y.
Sakai, H. Shoji, and H. Matsue: “Neutron in-beamMössbauer spectroscopic study of iron disulﬁde atroom temperature”, International Conference on the
Applications of the Mössbauer Eﬀect (ICAME2005),
Montpellier, France, Sept. (2005).
Y. Kobayashi, H. Nonaka, J. Miyazaki, K. Kubo,
H. Ueno, A. Yoshimi, H. Miyoshi, D. Kameda, K.
Shimada, D. Nagae, K. Asahi, and Y. Yamada:“Reactions of 57 Mn implanted into solid oxygen”,
International Conference on the Applications of
the Mössbauer Eﬀect (ICAME2005), Montpellier,France, Sept. (2005).
Y. Yoshida, Y. Kobayashi, A. Yoshida, H. Ueno, K.
Hayakawa, K. Yukihira, F. Shimura, and F. Ambe:“The formation process of substitutional Fe atoms
via interstitial Fe atoms jumping into vacancies inSi”, International Conference on the Applicationsof the Mössbauer Eﬀect (ICAME2005), Montpellier,France, Sept. (2005).
H. Shimada, Y. Yamazaki, Y. Nakai, H. Oyama,
K. Ando, and A. Hatakeyama: “Momentum distributions of multiply charged argon ions produced at barrier-suppression ionization regime”,
Joint Conference on Ultrafast Optics 5 and Applications of High Field and Short Wavelength Sources
11(UFO/HFSW 2005), (The Optical Society ofAmerica and others), Nara, Sept. (2005).
Y. Yamazaki: “Accumulation,Cooling,Diagnostics,andManipulation of Antiprotons and Positrons”, The
Physical Society of Japan 2005 Autumn Meeting,Kyotanabe, Sept. (2005).
M. Hoshino, T. Kambara, Y. Kanai, R. H. Schuch, andY. Yamazaki: “Charge state correlations in largeangle scattering between slow Ne ion and Ar atom”,
The Physical Society of Japan 2005 Autumn Meeting, Kyotanabe, Sept. (2005).
H. Saitoh, Y. Enomoto, Y. Kanai, A. Mohri, and Y.
Yamazaki: “Formation of ﬁnite length thermalized
non-neutral plasma in an inhomogeneous magnetic
ﬁeld”, The Physical Society of Japan 2005 Autumn
Meeting, Kyotanabe, Sept. (2005).
T. Ikeda, Y. Kanai, T. Nebiki, T. Narusawa, and Y.
Yamazaki: “Ion-beam guide eﬀect of glass capillaries”, The Physical Society of Japan 2005 Autumn
Meeting, Kyotanabe, Sept. (2005).
Y. Kanai, M. Hoshino, T. Ikeda, T. Kambara, R.
Hellhammer, N. Stolterfoht, and Y. Yamazaki: “Ionbeam guide eﬀect of insulator capillaries”, The
Physical Society of Japan 2005 Autumn Meeting,Kyotanabe, Sept. (2005).
A. Mohri, H. Saitoh, Y. Kanai, and Y. Yamazaki:“Nonneutral plasma with a ﬁnite lengh in thermal
equilibrium formed in an axially symmetric nonuniform magnetic ﬁeld”, The Physical Society of Japan

2005 Autumn Meeting, Kyotanabe, Sept. (2005).
Y. Nagata, A. Mohri, N. Kuroda, H. Torii, M.
Shibata, H. Saitoh, Y. Kanai, K. Komaki, and Y.
Yamazaki: “Production of polarized anti-hydrogen
beam: a simulation of the orbit of anti-hydrogenatoms emerging out of a cusp trap”, The PhysicalSociety of Japan 2005 Autumn Meeting, Kyotanabe,
Sept. (2005).
Y. Miyamoto, M. Hoshino, Y. Kanai, Y. Nakai, M.
Kitajima, D. Tanaka, and Y. Yamazaki: “Single anddouble electron capture processes in slow N5+ -He
collisions”, The Physical Society of Japan 2005 Autumn Meeting, Kyotanabe, Sept. (2005).
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: “Study of the resonant
electron capture and decay processes for N ions using
metal microcapillary targets”, The Physical Societyof Japan 2005 Autumn Meeting, Kyotanabe, Sept.
(2005).
Y. Yamazaki: “HCI-capillary interactions: Towards
Nano-beam formation and applications”, International Workshop on Interdisciplinary Research with
Slow Ion Beams 2005 (IRSIB 05), (Centre Interuniversitaire de Ressources Informatiques de Lorraine
and others), Caen, France, Oct. (2005).
T. Matsuzaki, K. Ishida, N. Kawamura, H. Imao, Y.
Matsuda, M. Iwasaki, K. Nagamine, S. Nakamura,
M. Kato, H. Sugai, A. Uritani, H. Harano, and G. H.
Eaton: “Temperature dependence of muon transfer
rate to the accumulated 3 He in T2 solid obseved in
the muon catalyzed t-t fusion process”, ISSP Workshop on Science of Hydrogen in Solid, (The Insitituteof Solid State Physics), Kashiwa, Nov. (2005).
T. Matsuzaki: “Studies of molecular magnetism with
µSR method under multiple extreme conditions at
RIKEN-RAL Muon Facility”, RIKEN Symposium
on Molecular Ensemble 2005, Wako, Nov. (2005).
T. Ikeda, Y. Kanai, T. Kojima, T. Nebiki, T.
Narusawa, and Y. Yamazaki: “Production of a
sub-micron sized highly charged ion beam using
glass capillary”, 6th Ion Beam Analysis of Surface,(JSAP), Kyoto, Dec. (2005).
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: “Study of the formation and decay of multiply and highly excited statesin the interaction of N ions using Ni microcapillarytarget”, 6th Ion Beam Analysis of Surface, (JSAP),
Kyoto, Dec. (2005).

4.

Radiochemistry, radiation chemistry, and radiation biology

R. Hirunuma, K. Igarashi, H. Saito, Y. Miyazawa, H.
Haba, H. Takeichi, T. Abe, and S. Enomoto: “Accumulation of various metals in Lotus japonicus using291

the multitracer technique”, 124th Annual Meeting of
the Pharmaceutical Society of Japan, Osaka, Mar.
(2004).
K. Ishibashi, T. Suzuki, T. Togawa, R. Hirunuma,
H. Haba, S. Enomoto, K. Nishio, and S. Tanabe:“Study of metal sensitivity and detoxiﬁcation mechanism in cisplatin resistant cell line”, 124th Annual
Meeting of the Pharmaceutical Society of Japan,
Osaka, Mar. (2004).
S. Ohata, T. Suzuki, T. Togawa, K. Nishio,
R. Hirunuma, H. Haba, S. Enomoto, and S.
Tanabe: “Study on Cadmium-resistance in MRP5overproducing cell line”, 124th Annual Meeting of
the Pharmaceutical Society of Japan, Osaka, Mar.
(2004).
R. Hirunuma, K. Igarashi, H. Saito, Y. Miyazawa, H.
Haba, H. Takeichi, T. Abe, and S. Enomoto: “Research on puriﬁcation of soil and water pollution by
the heavy metals using Lotus japonicus”, 14th Symposium on Roles of Metals in Biological Reactions,Biology and Medicine (SRM 2004), (The Pharmaceutical Society of Japan), Shizuoka, June (2004).
T. Abe, H. Saito, T. Matsuyama, H. Ryuto, N.
Fukunishi, Y. Yano, and S. Yoshida: “Morphological mutants of rice by heavy ion-beam irradiation”,
18th International Conference on Plant Growth Substances (IPGSA Conference 2004), (International
Plant Growth Substances Association), Canberra,
Australia, Sept. (2004).
Y. Kobayashi: “Application of in-beam mossbauer
spectroscopy to inorganic chemistry”, 1st TRIAC
Workshop, (KEK), Tokai-mura, Ibaraki Pref., Sept.
(2004).
W. Sato: “Applications of the on-line perturbed angular correlation method to condensed matter science”,
1st TRIAC Workshop, (KEK), Tokai-mura, Ibaraki
Pref., Sept. (2004).
H. Saito, T. Abe, N. Fukunishi, H. Ryuto, K. Miyazaki,
T. Kusumi, K. Suzuki, and S. Yoshida: “Mutation
breeding by heavy-ion beam irradiation on Verbena
hybrida: isolation and characterization of sterile mutants”, 5th International Symposium on In Vitro
Culture and Horticultural Breeding (5th IVCHB
Symposium), (International Sciety for Horticultural
Sciences), Debrecen, Hungary, Sept. (2004).
K. Kubo, Y. Kobayashi, Y. Nemoto, Y. Yamada, Y.
Sakai, H. Shoji, C. Yonezawa, and H. Matsue: “A
neutron in-beam mossbauer spectrum of iron disulﬁde”, 2004 Annual Meeting on the Japan Society of
Nuclear and Radiochemical Sciences and 48th Symposium on Radiochemistry, Tokyo, Oct. (2004).
W. Sato, H. Ueno, H. Watanabe, H. Miyoshi, A.
Yoshimi, D. Kameda, J. Kaihara, K. Shimada, T.
Ito, S. Suda, Y. Kobayashi, A. Shinohara, and K.
Asahi: “Application of the on-line pAC method tocondensed matter studies”, 2004 Annual Meetingon the Japan Society of Nuclear and Radiochemical

292

Sciences and 48th Symposium on Radiochemistry,
Tokyo, Oct. (2004).
K. Kubo, Y. Kobayashi, Y. Yamada, Y. Nemoto, T.
Saito, Y. Sakai, H. Shoji, C. Yonezawa, H. Matsue,
and M. Nakada: “Neutron in-beam Mössbauer spectroscopy with a parallel plate avalanche counter”,
International Symposium on Industrial Applicationsof the Mössbauer Eﬀect, Madrid, Spain, Oct. (2004).
Y. Kobayashi: “Applications of short-lived RI beam
to chemistry”, RIKEN Symposium on Research
Projects Dedicated to RIPS in the RIBF Conﬁguration, Wako, Oct. (2004).
K. Kubo: “Chemical states of krypton compounds”,
RIKEN Symposium on Research Projects Dedicatedto RIPS in the RIBF Conﬁguration, Wako, Oct.
(2004).
W. Sato: “Materials science using on-line PAC
method”, RIKEN Symposium on Research Projects
Dedicated to RIPS in the RIBF Conﬁguration,
Wako, Oct. (2004).
Y. Yoshida: “Materials science with GeV-energy implantations: Compared with low energy ion implantations”, RIKEN Symposium on Research Projects
Dedicated to RIPS in the RIBF Conﬁguration,
Wako, Oct. (2004).
Y. Yamada: “Mossbauer Spectra of Thin Fe Foil
Produced by Laser Evaporation”, Special Research
Meeting on New Developments in Solid State
Physics with Probes of Radiation and Nuclei, (Kyoto
University Research Reactor Institute), Kumatoricho, Osaka Pref., Nov. (2004).
Y. Kobayashi: “Oxidation states of Fe atoms implanted into solid oxygen”, Special Research Meeting on New Developments in Solid State Physics
with Probes of Radiation and Nuclei, (Kyoto University Research Reactor Institute), Kumatori-cho,Osaka Pref., Nov. (2004).
Y. Yamamoto, H. Saito, T. Matsuyama, H. Ryuto, T.
Abe, N. Fukunishi, and S. Yoshida: “Genetic mutation by heavy ion beam irradiation”, Arabidopsis
thaliana Workshop 2004, (The University of Tokyo),Tokyo, Nov. (2004).
Y. Kobayashi: “Chemical states of Fe atoms implanted
into solid oxygen”, RIKEN Symposium on Studies
on Condensed Matter Physics, Atomic Physics, Hyperﬁne Interactions and Biomedical Sciences using
RIKEN Accelerators, Wako, Jan. (2005).
M. Tomita: “Eﬀect of heavy ion irradiation oncell killing and DNA double-strand break repair”,
RIKEN Symposium on Studies on Condensed Matter Physics, Atomic Physics, Hyperﬁne Interactions
and Biomedical Sciences using RIKEN Accelerators,
Wako, Jan. (2005).
Y. Yamamoto: “For evaluation of genetic eﬀects onplants by heavy ion beam irradiation”, RIKEN Symposium on Studies on Condensed Matter Physics,
Atomic Physics, Hyperﬁne Interactions and Biomed-

ical Sciences using RIKEN Accelerators, Wako, Jan.
(2005).
Y. Yoshida: “Jump process of Fe atoms in Si”,
RIKEN Symposium on Studies on Condensed Matter Physics, Atomic Physics, Hyperﬁne Interactions
and Biomedical Sciences using RIKEN Accelerators,
Wako, Jan. (2005).
T. Abe: “Development of ion-beam breeding technology”, 56th CIST Colloquium for Faculty of Photonics Science, (Chitose Institute of Science and Technology), Chitose, Feb. (2005).
H. Haba: “Future plans for superheavy element chemistry (Experiment)”, 3rd Workshop on Nuclear andChemical Properties of Heavy Elements, (Kyoto
University Research Reactor Institute), Kumatoricho, Osaka Pref., Mar. (2005).
K. Kubo, Y. Kobayashi, H. Nonaka, Y. Yamada, Y.
Sakai, H. Shoji, and H. Matsue: “A mossbauer spectroscopic study on the products of neutron induce
reaction in irondisulﬁde”, 85th National Meeting of
the Chemical Society of Japan, Yokohama, Mar.
(2005).
Y. Kobayashi, H. Nonaka, J. Miyazaki, K. Kubo, H.
Ueno, H. Miyoshi, D. Kameda, K. Shimada, D.
Nagae, and Y. Yamada: “Chemical States of 57Fe
Decayed from 57Mn after Implantation into Solid
Oxygen”, 85th National Meeting of the Chemical
Society of Japan, Yokohama, Mar. (2005).
Y. Kitamoto, D. Saika, K. Matsuo, Y. Tani, H.
Hasegawa, T. Yoshimura, W. Sato, N. Takahashi,
H. Haba, S. Enomoto, and A. Shinohara: “Development of an on-line solvent extraction apparatus
for superheavy element chemistry”, 85th National
Meeting of the Chemical Society of Japan, Yokohama, Mar. (2005).
H. Haba, K. Tsukada, K. Akiyama, M. Asai, A.
Toyoshima, Y. Ishii, I. Nishinaka, T. Sato, Y.
Nagame, J. Saito, M. Ito, S. Goto, H. Kudo, Y.
Oura, and K. Sueki: “Reversed-phase extraction
chromatography of Zr and Hf in the TBP/HCl system: Model experiments for chemical characterization of element 104, rutherfordium”, 85th National
Meeting of the Chemical Society of Japan, Yokohama, Mar. (2005).
H. Saito, M. Nakano, H. Ryuto, N. Fukunishi, and
T. Abe: “Mutation induction by heavy-ion beamirradiation in daylily, Hemerocallis hybrida”, 2005
Spring Meeting of Japanese Society for Horticultural
Science, Tsukuba, Apr. (2005).
M. Tomita, M. Aoki, and Y. Furusawa: “Molecular response of DNA double-starand break repair proteinsto DNA clustered damages”, Heisei16nendo HIMAC
Kyodo Riyo Kenkyu Seika Happyokai, (National Institute of Radiological Sciences), Chiba, Apr. (2005).
T. Morishita, H. Yamaguchi, K. Degi, H. Asaumi, Y.
Hase, A. Tanaka, T. Abe, H. Saito, and S. Yoshida:“Dose responce and mutation eﬀects of ion beams

and gamma rays irradiation in perilla seeds”, 2nd
Meeting of the Ion Beam Breeding Society, Wako,
May (2005).
H. Ryuto, H. Saito, Y. Yamamoto, Y. Hayashi, N.
Fukunishi, M. Kase, T. Abe, and Y. Yano: “Heavyion beam irradiation system for biological samples
in RIKEN”, 2nd Meeting of the Ion Beam Breeding
Society, Wako, May (2005).
K. Ohkoshi, T. Nagashima, Y. Nishikawa, R. Hayashi,
M. Ohara, Y. Ito, T. Abe, K. Sakamoto, N.
Fukunishi, and H. Ryuto: “Induction of glutinous
rice mutants and characteristics of its progenies”,
2nd Meeting of the Ion Beam Breeding Society,
Wako, May (2005).
N. Ohtsubo, R. Aida, T. Abe, and S. Yoshida: “Modiﬁcation of chrysanthemum by ion beam irradiation”, 2nd Meeting of the Ion Beam Breeding Society, Wako, May (2005).
K. Furukawa, S. Kobayashi, K. Sakamoto, T. Ozaki,
and T. Abe: “Mutation breeding of orchids by ion
beam”, 2nd Meeting of the Ion Beam Breeding Society, Wako, May (2005).
I. Honda, K. Kikuchi, S. Matsuo, M. Fukuda, H. Saito,
T. Abe, and S. Yoshida: “Short internode and pericarp mutants of sweet pepper Capsicum annuus L.
induced by heavy ion irradiation”, 2nd Meeting of
the Ion Beam Breeding Society, Wako, May (2005).
M. Tomita, T. Funayama, S. Wada, Y. Kobayashi, and
T. Sakashita: “Imaging analysis of the mechanismsof low dose radiation-induced DNA double-strand
break repair”, 14th TIARA Research Review Meeting, (Takasaki Radiation Chemistry Research Establishment, JAERI), Takasaki, June (2005).
Y. Yamamoto, H. Saito, H. Ryuto, N. Fukunishi, S.
Yoshida, and T. Abe: “Eﬀective mutagenesis of Arabidopsis by heavy ion beam-irradiation”, 17th International Botanical Congress, Vienna, Austria, July
(2005).
H. Saito, Y. Hayashi, T. Kanaya, K. Suzuki, and T.
Abe: “Sterile mutant of Verbena hybrida induced byheavy-ion beam irradiation and wild species V. peruviana exhibit self-incompatible phenotype”, 17th
International Botanical Congress, Vienna, Austria,
July (2005).
C. Ikari, N. Shitsukawa, S. Shimada, T. Abe, K.
Sakamoto, H. Saito, and K. Murai: “Einkorn wheat
mutant, mvp, which shows maintained vegetative
phase is caused by mutation of wheat APETALA1”,
10th International Congress of SABRAO, (The Society for the Advancement of Breeding Researches
in Asia and Oceania), Tsukuba, Aug. (2005).
C. Ikari, N. Shitsukawa, S. Shimada, T. Abe, K.
Sakamoto, H. Saito, and K. Murai: “Einkorn wheat
mutant, mvp, which shows maintained vegetative
phase is caused by mutation of wheat APETALA1”,
47th Symposium in 107th and 108th Congress of the
Breeding Society of Japan, Tsukuba, Aug. (2005).

293

H. Ichida, T. Koba, T. Abe, and T. Matsuyama:“Mesorhizobium loti and Bradyrhizobium japonicum
genome scanning by virtual image restriction landmark genome scanning (Vi-RLGS)”, 15th Annual
Meeting of Japanese Society of Plant Microbe Interactions, Takamatsu, Sept. (2005).
D. Saika, Y. Kitamoto, K. Matsuo, T. Tashiro, T.
Takabe, T. Yoshimura, W. Sato, N. Takahashi, H.
Haba, S. Enomoto, and A. Shinohara: “Development of online solvent extraction system with microchip”, 2005 Annual Meeting on the Japan Society of Nuclear and Radiochemical Sciences and 49th
Symposium on Radiochemistry, Kanazawa, Sept.
(2005).
T. Takabe, Y. Kitamoto, D. Saika, K. Matsuo, T.
Tashiro, T. Yoshimura, H. Haba, D. Kaji, and A.
Shinohara: “Development of the gas-jet transportsystem for the superheavy element chemistry using
the RIKEN AVF cyclotron”, 2005 Annual Meetingon the Japan Society of Nuclear and Radiochemical
Sciences and 49th Symposium on Radiochemistry,
Kanazawa, Sept. (2005).
S. Kamataki, K. Morishita, H. Haba, and A.
Yokoyama: “Distribution coeﬃcients measured with
non-carrier tracers of Zr-88 and Hf-175 on TBPResin in hydrochloric acid and nitric acid solutions”,
2005 Annual Meeting on the Japan Society of Nuclear and Radiochemical Sciences and 49th Symposium on Radiochemistry, Kanazawa, Sept. (2005).
A. Toyoshima, H. Haba, K. Tsukada, M. Asai, K.
Akiyama, S. Goto, Y. Ishii, W. Sato, K. Matsuo, D.
Saika, Y. Kitamoto, A. Yokoyama, M. Sakama, Y.
Oura, I. Nishinaka, T. Sato, T. Ichikawa, M. Hirata,
S. Ichikawa, K. Sueki, A. Shinohara, H. Kudo, Y.
Nagame, H. Nakahara, and M. Schaedel: “Fluoride
complexation of rutherfordium”, 2005 Annual Meeting on the Japan Society of Nuclear and Radiochemical Sciences and 49th Symposium on Radiochemistry, Kanazawa, Sept. (2005).
K. Washiyama, Y. Kanayama, H. Haba, S. Enomoto,and R. Amano: “Production and application of lead203 (203 Pb) isotope for nuclear medicine”, 2005 Annual Meeting on the Japan Society of Nuclear andRadiochemical Sciences and 49th Symposium on Radiochemistry, Kanazawa, Sept. (2005).
A. Toyoshima, H. Haba, K. Tsukada, K. Akiyama, M.
Asai, Y. Ishii, Y. Tome, I. Nishinaka, T. Ichikawa,
T. Sato, S. Ichikawa, Y. Nagame, W. Sato, K.
Matsuo, Y. Kitamoto, T. Tashiro, A. Shinohara,
T. Ikezawa, M. Sakamaki, S. Goto, H. Kudo, M.
Arai, S. Kamataki, A. Yokoyama, Y. Oura, and K.
Sueki: “Reversed-phase extraction chromatographyof rutherfordium in the TBP-HCl system”, 2005 Annual Meeting on the Japan Society of Nuclear andRadiochemical Sciences and 49th Symposium on Radiochemistry, Kanazawa, Sept. (2005).
Y. Kitamoto, D. Saika, K. Matsuo, T. Takabe, T.

294

Tashiro, W. Sato, N. Takahashi, T. Yoshimura,
H. Haba, S. Enomoto, T. Mitsugashira, and A.
Shinohara: “Separation of the actinide elements bycapillary electrophoresis and derivation of the ion radius”, 2005 Annual Meeting on the Japan Society of
Nuclear and Radiochemical Sciences and 49th Symposium on Radiochemistry, Kanazawa, Sept. (2005).
S. Motomura, S. Enomoto, H. Haba, Y. Gono, andY. Yano: “Multitracer imaging by strip germanium
telescope”, 2nd Joint Meeting of the Nuclear Physics
Divisions of the APS and JPS (Hawaii 2005), Maui,
USA, Sept. (2005).
H. Haba: “Present status of the superheavy element
chemistry in RIKEN”, Scientiﬁc Meeting of the
Kyoto University Research Reactor Institute, Osaka,
Sept. (2005).
T. Abe: “Ion-beam irradiation on mutation breedingfor ornamental plants”, 5th Technical Seminar on
Accelerator Application, (Radiation Application Development Association), Kagoshima, Oct. (2005).
Y. Kobayashi, Y. Tsuruoka, K. Kubo, H. Nonaka,
Y. Yamada, Y. Sakai, H. Shoji, W. Sato, A.
Shinohara, Y. Watanabe, and H. Matsue: “Mossbauer spectroscopic study of 57Fe species producedby 56Fe(n,gamma)57Fe Reaction in iron disulﬁde”,
Asia-Paciﬁc Symposium on Radiochemistry 2005
(APSORC-05), Beijing, China, Oct. (2005).
H. Saito, Y. Hayashi, H. Ryuto, N. Fukunishi, T. Abe,T. Kanaya, M. Sugiyama, K. Suzuki, T. Terakawa,
N. Ohtsubo, and R. Aida: “Induction of sterile mutants by heavy-ion beam irradiation in horticultural
plants”, 11th Radiation Process Symposium, (Radiation Application Development Association), Tokyo,
Dec. (2005).
Y. Kobayashi, H. Nonaka, J. Miyazaki, K. Kubo,
H. Ueno, A. Yoshimi, H. Miyoshi, D. Kameda, K.
Shimada, D. Nagae, and Y. Yamada: “57 Mn implantation Mössbauer study into solid oxygen”, International Chemical Congress of Paciﬁc Basin Societies(PACIFICHEM 2005), Honolulu, USA, Dec. (2005).
K. Kubo, Y. Tsuruoka, Y. Kobayashi, Y. Yamada,
Y. Sakai, H. Shoji, W. Sato, Y. Watanabe, and
H. Matsue: “Mössbauer Spectroscopic Study of the
Chemical Eﬀects of Neutron Capture Reaction in
Iron Disulﬁde”, International Chemical Congress of
Paciﬁc Basin Societies (PACIFICHEM 2005), Honolulu, USA, Dec. (2005).

5. Material Analysis
T. Kuribayashi, K. Ushida, S. Kashiwagi, M.
Kawaguchi, R. Kuroda, H. Hirama, Y. Hama, andM. Washio: “Development of picosecond pulse radiolysis system at Waseda University”, 47th Symposium on Radiation Chemistry, (Japanese Society ofRadiation Chemistry), Sapporo, Oct. (2004).

6. RIKEN-BNL Collaboration
K. Hasuko, M. Grosse-Perdekamp, J. S. Lange, A.
Ogawa, and V. Siegle: “Future Measurements ofSpin Dependent Fragmentation Functions in e+eAnnihilation at Belle”, 8th Conference on the Intersections of Particle and Nuclear Physics (CIPANP
2003), New York, USA, May (2003).
N. Ishii and H. Suganuma: “Properties of Thermal
Glueballs”, International Conference on Color Conﬁnement and Hadrons in Quantum Chromodynamics: Conﬁnement 2003, (International Research Center of Science (IRCS) and RIKEN), Wako, July
(2003).
K. Hashimoto and T. Izubuchi: “Static quark potentialfrom two ﬂavor dynamical domain-wall QCD”, 59th
Annual Meeting of the Physical Society of Japan,
Fukuoka, Mar. (2004).
K. Sudo and M. Hirai: “Theoretical prospects on
π 0 double spin asymmetry at RHIC”, 59th Annual
Meeting of the Physical Society of Japan, Fukuoka,
Mar. (2004).
K. Sudo and M. Hirai: “Comment on π 0 double
spin asymmetry at RHIC”, RIKEN-TODAI MiniWorkshop on “Topics in Hadron Physics at RHIC”,
Wako, Mar. (2004).
K. Sudo and M. Hirai: “Eﬀects of ∆g(x) on the π 0spin asymmetry at RHIC”, 12th International Workshop on Deep Inelastic Scattering (DIS2004), High
Tatras, Slovakia, Apr. (2004).
T. Izubuchi: “Hadron Spectrum and Decay Constants from NF = 2 Domain-Wall QCD”, LATTICE
2004: 22nd International Symposium on Lattice
Field Theory, (Fermi National Accelerator Laboratory), Batavia, USA, June (2004).
K. Hashimoto and T. Izubuchi: “Static Q̄-Q Potential from Nf =2 Dynamical Domain-Wall QCD”,
LATTICE 2004: 22nd International Symposium on
Lattice Field Theory, (Fermi National Accelerator
Laboratory), Batavia, USA, June (2004).
K. Hashimoto and T. Izubuchi: “Analysis of Static
Quark Potential in Domain-Wall QCD”, 2004 Autumn Meeting of the Physical Society of Japan, Aomori and Kochi, Sept. (2004).
K. Sudo and H. Yokoya: “Charm-associated W boson
production at RHIC and polarized s quark distribution”, 2004 Autumn Meeting of the Physical Societyof Japan, Aomori and Kochi, Sept. (2004).
K. Okada and PHENIX√Collaboratio: “Measurementof prompt photon in s = 200 GeV pp collisions”,
2004 Autumn Meeting of the Physical Society ofJapan, Aomori and Kochi, Sept. (2004).
M. Togawa and PHENIX Collaboratio:√ “Measurementof single electron spectrum in s = 200 GeV p-p
collisions at RHIC-PHENIX”, 2004 Autumn Meeting of the Physical Society of Japan, Aomori and
Kochi, Sept. (2004).

H. Okada, I. Alekseev, N. Saito, and D. Svirida: “Measurement of the analyzing power in pp elastic scattering in the peak CNI region at RHIC”, 2004 Autumn Meeting of the Physical Society of Japan, Aomori and Kochi, Sept. (2004).
O. Jinnouchi, I. G. Alekseev, A. Bravar, G. Bunce,
S. Dhawan, H. Huang, G. Igo, V. P. Kanavets,
K. Kurita, H. Okada, H. Spinka, N. Saito, and J.
Wood: “Measurement of the analyzing power ofproton-carbon elastic scattering in the CNI region
at RHIC”, 2004 Autumn Meeting of the PhysicalSociety of Japan, Aomori and Kochi, Sept. (2004).
Y. Goto: “Single transverse-spin asymmetry measurement in neutral pion and charged hadron production
at PHENIX”, 2004 Autumn Meeting of the PhysicalSociety of Japan, Aomori and Kochi, Sept. (2004).
T. Izubuchi: “Lattice QCD with dynamical domain
wall fermions”, Lattice QCD simulations via International Research Network (ILFT04), (CCS, University of Tsukuba and KEK), Izu, Sept. (2004).
K. Okada and PHENIX√Collaboratio: “Measurementof prompt photon in s = 200 GeV pp collisions”,
16th International Spin Physics Symposium (SPIN
2004), (ICTP), Trieste, Italy, Oct. (2004).
S. Kojima, H. Tatsukawa, Y. Suzuki, M. Okuno, and
M. A. Zern: “Potential role of polyamines as regulators of blood vessel formation and hepatic apoptosis
via controling activity of tissue transglutaminase”,
2004 International Conference on Polyamines: Functions and Clinical Application, Kisarazu, Nov.–Dec.
(2004).
T. Izubuchi: “The electromagnetic splitting andgµ −2 light-by-light contribution”, Workshop on the
Physics Programme of the RBRC and UKQCDQCDOC Machines, (RIKEN), Upton, USA, Nov.
(2004).
K. Iida: “Magnetic vortex in color-ﬂavor locked quark
matter”, 60th Annual Meeting of Physical Societyof Japan, Noda, Mar. (2005).
M. Ohtani, T. Hatsuda, and S. Digal: “Phase transitions of color superconductor in the GinzburgLandau approach on the lattice”, 60th Annual Meeting of Physical Society of Japan, Noda, Mar. (2005).
H. Kawamura, J. Kodaira, H. Shimizu, and K. Tanaka:“QT resummation in transversely polarized DrellYan process”, International Conference on QCD
and Hadronic Physics, (Pekin University), Beijing,
China, June (2005).
H. Kawamura, J. Kodaira, H. Shimizu, and K. Tanaka:“QT resummation in transversely polarized DrellYan process”, 5th Circum-Pan-Paciﬁc Symposium
on High Energy Spin Physics (SPIN 2005), (Tokyo
Institute of Technology), Tokyo, July (2005).
M. Ohtani, T. Hatsuda, and S. Digal: “Thermal phasetransition of color superconductivity with GinzburgLandau eﬀective action on the lattice”, Workshop
on Extreme QCD, (University of Wales, Swansea),295

Swansea, UK, Aug. (2005).
K. Iida: “Feedback eﬀects on the pairing interaction incolor superconductors near the transition temperature”, 2nd Joint Meeting of the Nuclear Physics Divisions of the APS and JPS (Hawaii 2005), Maui,
USA, Sept. (2005).
M. Ohtani, A. Iwazaki, O. Morimatsu, and T.
Nishikawa: “Vortex excitation and quark spectrum
in color ferromagnetic state in cold dense matter”,
2nd Joint Meeting of the Nuclear Physics Divisionsof the APS and JPS (Hawaii 2005), Maui, USA,
Sept. (2005).
K. Iida: “Phase transitions in dense matter and quarkstars”, 2005 Fall Annual Meeting of Astronomy Society of Japan, Sapporo, Oct. (2005).

296

H. Kawamura, J. Kodaira, H. Shimizu, and K. Tanaka:“QT resummation in transversely polarized DrellYan process”, 7th International Symposium on Radiative Corrections, (Sokendai and KEK), Hayamamachi, Kanagawa Pref., Oct. (2005).
K. Iida: “Phase transitions in dense matter and quarkstars”, Particle-, Nuclear-, and Astro-Physics Colloquium, (Tokyo Institute of Technology), Tokyo, Oct.
(2005).
M. Ohtani, S. Digal, and T. Hatsuda: “Thermal phasetransition of color superconductivity with GinzburgLandau action on the lattice”, Japan-Korea MiniWorkshop on QCD and hidden local symmetry inmatter under extreme conditions, (Nagoya University), Nagoya, Nov. (2005).

IX. LIST OF SYMPOSIA(Jan.–Dec. 2005)
1) Studies on Condensed Matter Physics, Atomic Physics, Hyperfine Interactions and Biomedical Sciences
Using RIKEN Accelerators
28 Jan., Wako, Atomic Physics Lab., RIKEN
2) International Symposium on Correlation Dynamics in Nuclei (CDN05)
31 Jan.–4 Feb., Tokyo, Heavy Ion Nuclear Physics Lab., RIKEN
3) International Workshop on “Chiral Restoration in Nuclear Medium”
15–17 Feb., Wako, Advanced Meson Science Lab., RIKEN
4) Classical and Quantum Aspects of the Color Glass Condensate
7–11 Mar., New York, USA, RBRC, RIKEN
5) Jet Correlations at RHIC
10–11 Mar., New York, USA, RBRC, RIKEN
6) Workshop on Physics with Ultra Slow Antiproton Beams
14–16 Mar., Wako, Atomic Physics Lab., RIKEN
7) RIKEN One-day Workshop on Breakup Reactions
15 Apr., Wako, Heavy Ion Nucl. Phys. Lab., RIKEN
8) Particles and Nuclei, the Playing Fields of Physics
24 Apr., Tokyo, Radiation Lab., RIKEN
9) Detector Workshop
11 May, Wako, Radiation Lab., RIKEN
10) RIKEN RIBF International Workshop “Collective Motions in Unstable Nuclei: Experiments vs. Theories”
24–26 May, Wako, Heavy Ion Nucl. Phys. Lab., RIKEN
11) RBRC QCDOC Computer Dedication and Symposium
1–3 June, New York, USA, RBRC, RIKEN
12) RIKEN Cluster Project Status Report
3 June, Wako, Heavy Ion Nucl. Phys. Lab., RIKEN
13) Spin Fest Workshop At Nikko
17–18 Aug., Nikko, Radiation Lab., RIKEN
14) RIBF Workshop on Study of Nuclear Spectroscopy with Stopped/Slow RI Beam
9 Sep., Wako, Applied Nuclear Physics Lab., and Atomic Physics Lab., RIKEN
15) Mini Workshop on “Pair Correlation in Unstable Nuclei”
12–13 Sep., Wako, Heavy Ion Nucl. Phys. Lab., RIKEN
16) Single Spin Asymmetries
27–29 Sep., New York, USA, RBRC, RIKEN
17) Mini Workshop on “Two-Neutron Correlation in Loosely Bound Nucleus”
19–20 Oct., Wako, RI Physics Lab., RIKEN

29718) International Symposium on Origin of Matter and Evolution of Galaxies (OMEG05)
8–11 Nov., Tokyo, Heavy Ion Nuclear Physics Lab., RIKEN
19) International Symposium on the 15 Years of Spectrometer SMART and New Turn to RIBF
11–12 Nov., Wako, Heavy Ion Nuclear Physics Lab., RIKEN
20) 11th International Workshop on Polarized Sources and Targets
14–17 Nov., Tokyo, Heavy Ion Nuclear Physics Lab., Applied Nuclear Physics Lab., and Atomic Physics
Lab., RIKEN and CNS21) RHIC-SPIN-J Physics Discussion No.60
3 Dec., Wako, Radiation Lab., RIKEN22) RIKEN-CNS RIBF International Workshop “Correlation and Condensation: New Features in Loosely Boundand Unbound Nuclear States”
8–10 Dec., Wako, Heavy Ion Nucl. Phys. Lab., RIKEN23) Odderon Searches at RHIC
12 Dec., New York, USA, RBRC, RIKEN24) Heavy Flavor Productions & Hot/Dense Quark Matter
15 Dec., New York, USA, RBRC, RIKEN
25) Workshop on Nuclear Physics Collaboration between Germany and Japan
16–17 Dec., Wako and Tokyo, Heavy Ion Nuclear Physics Lab., RIKEN

298

X. LIST OF SEMINARS(Jan.–Dec. 2005)

RIKEN Nuclear Physics Monthly Colloquium
1) T. Nagae, KEK (Tsukuba), 17 May“Nuclear physics at J-PARC”
2) S. A. Bass, Duke University and RBRC (USA), 7
June“The quest for the quark-gluon-plasma”
3) P. Kienle, Technische Universität München (Germany), 21 June
“Pions in nuclei, a probe of chiral restoration”
4) H. Horiuchi, Kyoto University (Kyoto), 19 July
“Diverseness of nuclear structure”
5) H. En’yo, RIKEN (Wako), 1 Nov.
“In the quest of proton spin mystery”
6) G. Bollen, MSU (USA), 21 Nov.
“Thermalized beams from projectile fragmentation at the NSCL – First experiments and future
developments”
7) K. Makishima, University of Tokyo (Tokyo), 22
Dec.
“Search for nucleosynthesis in the cosmos”
8) K. Masuda, Nagoya University (Nagoya), 22 Dec.
“Study of 14C abundance in Yaku-Sugi cedar by
AMS method and clues to solar activity and super
novae”

Nuclear Physics Seminar
1) Y. Ishimaru, Ochanomizu University (Tokyo), 20
Jan.
“Trace of r-process elements recorded in Galaxy
formation stage”
2) I. Talmi, Weizmann Institute of Science (Israel),
9 Feb.
“Structure of light neutron righ nuclei”
3) L. Guo, Ibaraki University (Mito), 10 Feb.
“To what extent does the self-consistent meanﬁeld exist?”
4) P. Ring, Technische Universität München (Germany), 28 Feb.
“Collective modes and isospin properties of nuclei
far from stability”

5) A. E. L. Dieperink, Kernfysisch Versneller Instituut (The Netherland), 2 Mar.
“Nuclear physics aspects of neutron stars: Equation of state and thermal evolution”
6) T. Otuki, Tohoku University (Sendai), 18 Mar.
“Electron-capture decay rate of 7 Be encapsulated
in C60 cages”
7) A. M. Bernstein, MIT (USA), 31 Mar.
“The Pi Meson: From Yukawa to QCD”
8) A. M. Mukhamedzhanov, Cyclotron Institute,Texas A&M University (USA), 14 Apr.
“Can spectroscopic information be extracted
from transfer reactions?”
9) V. Y. Denisov, Institute for Nuclear Research(Ukraine), 10 May“Nucleus-nucleus potential and superheavy element production”
10) Zs. Dombrádi, Institute of Nuclear Research(ATOMKI) (Hungary), 20 May“In-beam gamma ray spectroscopy close to theneutron dripline”
11) D. T. Khoa, Institute for Nuclear Science & Technique, VAEC (Vietnam), 23 May“Microscopic study of the quasi-elastic nuclear
scattering”
12) M. Chiu, University of Illinois (USA), 11 July
“Sivers Measurement using back to back dihadrons”
13) D. Kawall, RBRC (USA), 20 July
“Testing fundamental symmetries with molecules”
14) K. N. Barish, UCR (USA), 20 July“High p T measurements at RHIC”
15) Z. Li, BNL (USA), 25 July
“Si detector development and radiation hardness
for nuclear and high energy physics experiments
at BNL and around the world”
16) T. Mibe, Ohio University (USA), 25 July“High statistics search for θ + in γ + d → K+ +K− + p(n) reaction”17) H. Okada, Kyoto University (Kyoto), 1 Aug.
“Absolute polarimetry in RHIC – How to measure
the beam polarization? What is the principle?”29918) I. Nakagawa, RIKEN (Wako), 1 Aug.
“Silicon-tungsten calorimeter for the forward direction in the PHENIX experiment at RHIC”
19) A. Kral, Czech Technical University in Prague(Czech), 8 Aug.
“Introduction to grid computing”
20) K. Aoki and K. Shoji, Kyoto University (Kyoto),
8 Aug.
“Trigger upgrade for high momentum muons tostudy the spin-ﬂavor structure of the proton at
RHIC-PHENIX”
21) T. Liska, Czech Technical University in Prague(Czech), 22 Aug.
“Massive data production on distributed computation environment”

RIBF Nuclear Physics Seminar
1) J. Terasaki, RIKEN (Wako), 26 Oct.
“Neutron number dependence of strength functions and incompressibility”
2) T. Noro, Kyushu University (Fukuoka), 2 Nov.
“Nuclear medium eﬀects studied by (p, 2p) reaction”
3) T. Kobayashi, Tohoku University (Sendai), 2
Nov.
“(p, 2p) reaction from carbon isotopes”
4) M. Smith, Oak Ridge National Laboratory(USA), 14 Nov.
“The rare isotope accelerator – Future U.S. facility for probing nuclei and exploding stars”
5) S. Amari, University of Washington (USA), 15
Nov.
“Nuclear synthesis recorded in meteorolite”
6) A. A. Ogloblin, Kurchatov Institute (Russia), 29
Nov.
“Some new points of interest in physics of exotic
proton-rich nuclei”
7) R. Seki, California State Univ. Northridge/
Caltech (USA), 6 Dec.
“Quantum Monte Carlo Lattice calculation ofthermal properties of low-density neutron matter”
8) P. Moeller, LANL (USA), 15 Dec.
“Nuclear shape isomers, shape coexistence, andnuclear ground state reﬂection and axial shapeasymmetries”

3009) G. C. Hillhouse, University of Stellenbosch (South
Africa), 15 Dec.
“Relativistic predictions of polarization phenomena in exclusive proton-induced proton-knockout
reactions”

Radiation Lab.
1) Y. Akaishi, KEK (Tsukuba), 18 Jan.
“Stracture and production of strange tribaryon”
2) T. Doi, RBRC, 29 Mar.
“Pentaquark baryon from QCD sum rule/lattice
QCD”
3) Y. Hatta, RBRC, 29 Mar.
“Perturbative odderon in the color glass condensate”
4) K. Kondo, Waseda University (Tokyo)/Tukuba
University (Tsukuba), 12 Apr.
“Topics on top quark: discovery. DLM. outlook”
5) R. Seidl, University of Illinois (USA), 20 June
“Measurements of chiral-odd fragmentation functions at Belle”
6) G. Schnell, Tokyo Institute of Technology(Tokyo), 20 June
“Transverse-spin physics at HERMES”

Atomic Physics Lab.
1) K. Omori, Institute for Molecular Science(Okazaki), 22 Feb.
“Phase sensitive memory in molecular wave packets: How to READ and WRITE with molecules”
2) N. Cherepkov, State University of Aerospace Instrumentation (Russia), 25 Feb.
“Non-dipole eﬀects in photoionization of atoms at
low energies”
3) K. Wendt, Johannes Gutenberg University Mainz(Germany), 30 Mar.
“Laser and ion source development for production
and spectroscopy of exotic species”
4) F. Vedel, Universite de Provence (France), 19
Apr.
“Recent results with a single trapped Ca+ ion”
5) Z.-C. Yan, University of New Brunswick(Canada), 10 June
“High-precision studies of few-body coulombic
systems”
6) B. D. DePaola, Kansas State University (USA),10 June“Measurement of population dynamics in coherent excitation”

Advanced Meson Science Lab.
1) T. Ito, University of Tennessee (USA), 6 Jan.
“Basic physics using a ultra-slow neutron”

7) T. Wang, Lanzhou University (China), 12 July
“Approaches on the study of highly charged ion
and solid surface interaction”

2) K. Morita, RIKEN (Wako), 17 Jan.
“The newly observed 113th element”

8) K. Zrost, Max-Plank Institute for Nuclear Physics(Germany), 12 July
“Interaction of intense optical few cycle pulses
with atoms”

3) H. Ejiri, Osaka University (Osaka)/ICU (Mitaka),
31 Jan.
“Neutrino masses by bb decays and MOON (Mo
Observatory Of Neutrinos)”

9) L. Tribedi, Tata Institute of Fundamental Research (India), 19 Aug.
“Some aspects of the interference eﬀect in fact ion
collisions with H2”4) P. Kienle, Technische Universität München (Germany), 28 Mar.
“Precision spectroscopy of exotic atoms andmesonic nuclear states”

10) H. Schmidt-Boecking, University Frankfurt (Germany), 22 Aug.
“The COLTRIMS reaction microscope – The tool
to explore the secrets of inner atomic and molecular dynamics”

5) K. Hachitani, Chiba University (Chiba), 4 Apr.
“Novel properties in ﬁlled skutterudite systems
studied by magnetic resonance”

11) J. Burgdoefer, Vienna University of Technology(Austria), 13 Sep.
“From hollow atoms to nanobeams”
12) T. Koshikawa, Osaka Electro-Communication
University (Neyagawa), 16 Sep.
“New trend of surface research by using LEEM
and PEEM”
13) K. Sakimoto, ISAS, JAXA (Sagamihara), 30 Sep.
“Collisions of antiprotons with atoms and molecules”
14) R. Schuch, Stockholm University (Sweden), 4
Oct.
“The GSI future facility ‘FAIR’ and atomic
physics in strong ﬁelds”
15) I. Izosimov, V. G. Khlopin Radium Institute(Russia), 4 Oct.
“Applications of lasers in chemistry and physics
in khlopin radium”
16) J. Sunchan, IPNS, KEK (Tsukuba), 14 Oct.
“Study on the diﬀusion of Li in solids using shortlived radioactive ion beams”
17) H. Winter, Humboldt-University of Berlin (Germany), 2 Dec.
“Studies on ultrathin ﬁlms using grazing ion scattering”

6) H. Nemura, RIKEN (Wako), 18 Apr.
“Study of strange few-body systems”
7) Y. Kobayashi, RIKEN (Wako), 30 May“The research of material sciences by use of thein-beam Mossbauer spectroscopy”
8) K. S. Myint, Mandalay University (Myanmar), 20
July“Structure and decay of tightly bound K− NN
three – body kaonic nucleus
9) H. Sakai, University of Tokyo (Tokyo), 5 Sep.
“Einstein was wrong? – Entangled two-proton
spin – correlation experiment for a test of Bell’sinequality (a test of EPR paradox)”10) M. Iio, RIKEN (Wako), 4 Nov.
“Development of the polarized deuterium target
for spin dependent nuclear fusion experiment in
the low energy region”
11) H. Ohnishi, RIKEN (Wako), 21 Nov.
“Study of the dense matter created in reletivistic
heavy ion collisions”
12) H. Nemura, RIKEN (Wako), 5 Dec.
“Pentaquark state of Λ (1405)”

RIBF Program
1) H. Geissel, GSI (Germany), 27 Apr.
“FAIR project at GSI”
2) L. Stingelin, PSI (Switzerland), 9 June301

“Beam-cavity interactions in high power cyclotrons”

14) D. Toublan, University of Illinois (USA), 4 Feb.
“QCD at small chemical potential”

3) J. Beyer, Physikalisch-Technische Bundesanstalt
Berlin (PTB) (Germany), 8 Aug.
“Concept for a CCC-beam current monitor forthe metrology light source of PTB”

15) T. Plehn, Max-Planck Institute for Physics (Germany), 9 Feb.
“Theory tools for supersymmetry at the LHC”

RIKEN BNL Research Center
1) F. Yuan , RBRC (USA), 13 Jan.
“Understanding single spin asymmetry in QCD”
2) C. Kouvaris, MIT (USA), 14 Jan.
“A hot bottle of water for aging neutron stars”
3) M. Golterman, San Francisco State University(USA), 18 Jan.
“Before sailing on a domain-wall sea”
4) J. Ferrandis, BNL (USA), 19 Jan.
“Supersymmetry breaking as the origin of ﬂavor”
5) Y. Shamir, Tel-Aviv University (Israel), 19 Jan.
“Locality of the staggered-fermion determinant:renormalization-group approach”
6) T. Lappi, Helsinki (Finland), 21 Jan.
“Particle production in the classical ﬁeld modelfor heavy ion collisions”
7) R. S. Longacre, BNL (USA), 21 Jan.
“Bubble model for central events in AuAu collisions at RHIC”
8) A. Kagan, FNAL (USA), 26 Jan.
“e+ e− → M1 M2 and annihilation in B decays”
9) Y. Hatta, RBRC (USA), 27 Jan.
“Perturbative odderon in the color glass condensate”
10) H. Nastase, Brown University (USA), 28 Jan.
“Black hole production, the Froissart bound, thesoft pomeron from AdS-CFT”
11) N. Brambilla, University of Milano (Itary), 31Jan.
“Nonrelativistic eﬀective ﬁeld theories of QCD”
12) D. Rainwater, University of Rochester (USA), 2
Feb.
“Pseudo-axions in little higgs models”
13) M. Forbes, MIT (USA), 3 Feb.
“Aspects of high density QCD: gapless superconductivity and Kaon condensation”

30216) A. Gal, Hebrew University (Israel), 11 Feb.
“Traces of θ + (1540) pentaquark in K+-nucleus
phenomenology”
17) B. Nelson, University of Pennsylvania (USA), 16Feb.
“Massive neutrinos and string theory”
18) T. Ikeda, RBRC (USA), 17 Feb.
“Balitsky-Kovchegov equation and the Froissart
bound”
19) D. Boer, Vrije Universiteit Amsterdam (TheNetherlands), 18 Feb.
“Azimuthal asymmetries from hadronic versus
QCD vacuum eﬀects”
20) O. Mena, FNAL (USA), 23 Feb.
“Cosmic neutrino spectroscopy and the early universe”
21) T. Sugihara, RBRC (USA), 24 Feb.
“Real-time simulation of quantum states withdensity matrix RG”
22) T. Kinoshita, Cornell University (USA), 2 Mar.
“Theory of lepton g-2: recent improvement of
QED terms”
23) T. Kaneko, KEK (Tsukuba)/BNL (USA), 3 Mar.
“Light hadron spectroscopy from CP-PACS/JLQCD”
24) B. Holstein, University of Amherst (USA), 4 Mar.
“Hadronic parity violation”25) I. Stewart, MIT (USA), 9 Mar.
“Factorization in b-decays and the soft-collinear
eﬀective theory”
26) H. Abuki, YITP, Kyoto University (Kyoto), 10Mar.
“Crossover from BCS to Bose-Einstein condensation in the relativistic superﬂuid: boson formation above the critical temperature”27) K. Ohnishi, YITP, Kyoto University (Kyoto), 17Mar.
“Non-equilibrium critical phenomena in the QCD
phase transitions”28) F. Petriello, Johns Hopkins University (USA), 23
Mar.
“High precision QCD at hadron colliders”
29) G. Dunne, University of Connecticut (USA), 24Mar.
“Mass dependence of the fermion determinant in
an instanton background”
30) H. Baer, Florida State University (USA), 30 Mar.
“Direct, indirect and collider searches for neutralino dark matter in SUSY models with nonuniversality”
31) M. Perelstein, Cornell University (USA), 6 Apr.
“Two topics in cosmoparticle physics”
32) N. Itoh, Sophia University (Tokyo), 7 Apr.
“Relativistic corrections to the SunyaevZeldovich Eﬀect for cluster of galaxies”“The QGP phase, the coupling, Debye-screening
and quarkonium binding”
43) H. Koura, ORNL (USA)/JAERI (Tsukuba), 23
June“Properties of unstable nuclei predicted by nuclear mass formula: superheavy nuclei and rprocess nucleosynthesis”
44) A. Baltz, BNL/RBRC (USA), 30 June“e+ e− pairs to all orders in Zα: SPS and RHIC
data; b = 0 limit”
45) S. Kretzer, BNL/RBRC (USA), 7 July
“Fragmentation functions: Fit update & inclusionof masses”
46) I. V. Heide, Bielefeld (Germany), 8 July
“Pion form-factors from the lattice QCD”

33) R. Kitano, IAS (USA), 13 Apr.
“Scenarios for supersymmetry cosmology andphenomenology”47) K. Agashe, John Hopkins University (USA), 13
July“Warped compactiﬁcations: Flavor, uniﬁcationand dark matter”

34) K. Tuchin, BNL (USA), 14 Apr.
“Black holes at RHIC?”48) S. Jeon, McGill (Canada), 15 July
“Charge transfer ﬂuctuations as a QGP signal”

35) D. Morrissey, University of Chicago (USA), 20
Apr.
“Dark matter and a baryon asymmetry from supersymmetry”

49) T. Matsuura, University of Tokyo (Tokyo), 21
July“Color superconductivity in Ginzburg-Landau
approach”

36) T. Doi, RBRC (USA), 21 Apr.
“Pentaquark baryon in anisotropic lattice QCD”

50) G. Nayak, SUNY (USA), 22 July
“Soft gluon production from constant chromoelectric ﬁeld at one loop level via Schwinger mechanism”

37) I. Stamatescu, University Heidelberg (Germany),
4 May“Learning from incomplete information and themathematical structure behind it”38) K. Fukushima, RBRC (USA), 5 May“Recent problems in color superconductivity”
39) G. Salam, University of Paris VI (France), 19 May“Impact of higher orders in the high-energy limit
of QCD”
40) A. Freitas, FNAL (USA), 25 May“Exploring supersymmetric dark matter in thestop co-annihilation region at colliders”
41) B. Sinha, Saha Institute (India), 27 May“The changing panorama of physical sciences –The indian kaleidoscope”
42) F. Zantow, BNL (USA), 16 June

51) A. Patel, Banglore (India), 10 Aug.
“Large-N QCD at strong transverse gauge coupling”52) M. Strikman, Penn State University (USA), 18
Aug.
“Probing small x QCD in ultaperipheral collisionsat LHC”
53) T. Falter, BNL (USA), 19 Aug.
“Hadron attenuation in nuclear DIS and HIC”
54) L. Frankfurt, Tel Aviv University (Israel), 25
Aug.
“On the critical phenomena in small x physics”
55) Y. Akiba, RBRC (USA), 30 Aug.
“News from quark matter (I): Perspectives fromPHENIX and STAR speakers”

30356) J. Dunlop, BNL (USA), 30 Aug.
“News from quark matter (I): Perspectives fromPHENIX and STAR speakers”
57) Y. Kovchegov, Ohio State University (USA), 30
Aug.
“Can thermalization be derived from Feynman diagrams?”
58) T. Yamazaki, RBRC (USA), 8 Sep.
“∆I = 3/2 kaon weak matrix elements with nonzero total momentum”
59) J. Laiho, FNAL (USA), 14 Sep.
“Staggered chiral perturbation theory and heavy
light form factors”
60) T. Umeda, BNL (USA), 15 Sep.
“Study of charmonia at ﬁnite temperature inquenched lattice QCD”
61) E. Leader, Imperial College (UK), 21 Sep.
“Higher twist and positivity constraints in polarized deep inelastic scattering”
62) J. Jia, Columbia University (USA), 23 Sep.
“Systematic study of back to back jets in
PHENIX”
63) T. Tait, ANL (USA), 28 Sep.
“Exploring warped space”“Higgs limits with a new standard model singlet”
70) A. Dumitru, Frankfurt University, 13 Oct.
“Instabilities in an anistropic quark-gluon
plasma”
71) S. Leupold, University of Giessen (Germany), 14
Oct.
“Weinberg sum rules, four-quark condensates andchiral restoration”72) R. Dermisek, IAS (USA), 19 Oct.
“Escaping large ﬁne tuning and little hierarchy
problems in NMSSM”
73) U. Maor, Tel Aviv University (Israel), 20 Oct.
“Gap survival probabilities and the fate of diﬀraction at exceedingly high energies”
74) F. Gelis, CEA/SPhT (France), 21 Oct.
“High density eﬀects on quark production in pA
and AA collisions”
75) S. Bar-Shalom, Technion (Israel), 26 Oct.
“Massive neutrinos in a grounds-up approach”
76) W. Kinney, Buﬀalo, SUNY (USA), 28 Oct.
“Inﬂation in the age of WMAP”
77) E. Lunghi, FNAL (USA), 2 Nov.
“B → Xs l l: status, phenomenology and implications for SUSY”

64) A. Rebhan, Vienna University of Technology(Austria), 30 Sep.
“Quark-gluon plasma instabilities in the hardloop approximation”78) C. Korthals-Altes, University Marseile (USA), 3
Nov.
“Quasi-particles and k-tensions in hot QCD”

65) S. Dutta, University of Delhi (India), 5 Oct.
“Measurement of higgs gauge boson couplings at
NLC”

79) T. Hirano, Columbia University (USA), 4 Nov.
“Perfect ﬂuidity of sQGP core and dissipative
hadronic corona”

66) J. Bartels, University Hamburg (Germany), 6
Oct.
“On the Pomeranchuk singularity and vector boson reggeization in electroweak theory”

80) M. Wingate, University of Washington (USA), 9Nov.
“Field theoretic methods for nonrelativistic
fermion gases”

67) P. Levai, KFKI Research Institute for Particle
and Nuclear Physics (RMKI) (Hungary), 6 Oct.
“Molecular dynamics simulation of strongly interacting quark matter”

81) K. Okada, RBRC (USA), 10 Nov.
“Direct photon production in p + p collisions at
sqrt(s) = 200 GeV”

68) J. Kotanski, Jagiellonian University (Poland), 7
Oct.
“Reggeized gluon states and anomalous dimensions in QCD”
69) S. Chang, New York University (USA), 12 Oct.

30482) H. Davoudiasl, University of Wisconsin (USA), 16
Nov.
“Detecting solar axions using Earth’s magnetic
ﬁeld”
83) P. Levai, KFKI Research Institute for Particle
and Nuclear Physics (RMKI) (Hungary), 17 Nov.

“Molecular dynamics simulation of strongly interacting quark matter”
84) S. Sasaki, RBRC (USA), 18 Nov.
“Spin physics from the lattice”
85) A. Ipp, ECT, Trento (Itary), 18 Nov.
“Thermodynamics of large Nf QCD at ﬁnite
chemical potential for weak and strong couplings”
86) G. Perez, LBNL (USA), 30 Nov.
“Observing dark energy via neutrino detectors”
87) D. Teaney, SUNY (USA), 1 Dec.
“Heay quark diﬀusion and lattice correlators”“The problem of conﬁnement in lattice gauge theory”
89) B. Lillie, University of Chicago (USA), 7
Dec., “Oﬀ-the-wall higgs in the randall-sundrum
model”
90) K. Tuchin, Iowa State University (USA), 8 Dec.
“Thermalization of color glass condensate”
91) E. Ponton, Columbia University (USA), 9 Dec.
“Resonances from two universal extra dimensions”
92) J. Ruppert, Duke University (USA), 9 Dec.
“Mach cones in an evolving medium”

88) M. Pepe, University of Bern (Switerland), 2 Dec.

305

XI. LIST OF PERSONNEL
Accelerator Research Program, RIKEN Frontier Research System
Program Director
Yasushige YANO
Supervisor for Accelerator Research Program
Hiromichi KAMITSUBO
Members
Hiromu OKAZOE∗1∗1∗2

Temporary Employee
Visiting Contract Oﬃcer

Visiting Members
Masayasu ISHIHARA
Accelerator Operation Group
Group Director
Masayuki KASE
Members
Mieko KOGURE
Visiting Members
Dung NGUYEN (INST, Vietnam)
RILAC Team
Team Leader
Masayuki KASE
Members
Eiji IKEZAWAAVF Team
Team Leader
Masayuki KASE
Members
Tadashi KAGEYAMARRC Team
Team Leader
Masayuki KASE
Members
Naohito INABE
SRC Team
Team Leader
Masayuki KASE
Members
Hiroki OKUNO

306

Atsushi YAMANAKA∗2

Beam Technology Development Team
Team Leader
Masayuki KASE
Members
Kiyoshi OGIWARA
Keiko KUMAGAI
Tamaki WATANABE
Sachiko ITO
Tadashi FUJINAWA∗2
Shigeru YOKOUCHI∗2

Makoto NAGASE
Masaki FUJIMAKI
Nobuhisa FUKUNISHI
Hiromichi RYUTO∗1
Misaki KOBAYASHI-KOMIYAMA∗2
Jiro FUJITA∗3∗1

Contract Researcher
Contract Technical Scientist∗3
Temporary Employee∗2

Visiting Members
Hiroaki ASAI (JAXA)
Toshiya CHIBA
Masahiko HAYASHI (JAXA)
Masatake HEMMI
Yoshiya IIDE (JAXA)
Naomi IKEDA (JAXA)
Chihiro KAMEZAWA (JAXA)
Kazuie KIMURA
Masanori KOSHIMIZU (Grad. Sch. Eng., Tohoku Univ.)
Satoshi KUBOYAMA (JAXA)
Masahiko MIDORIKAWA (JAXA)
Hideo MIKAMI (SHI Accel. Serv. Ltd.)
Yoshitoshi MIYAZAWA
Hideharu OHIRA (JAXA)
Katsumi OKA (JAXA)
Osamu OKUDAIRA (Adv. Res. Inst. Sci. Eng., Waseda Univ.)
Hiromitsu OOTOMO (JAXA)
Yohei SATOH (JAXA)
Osamu SHIMADA (JAXA)
Hiroyuki SHINDO (JAXA)
Ichiro YOKOYAMACryogenic Team
Team Leader
Masayuki KASE
Members
Kumio IKEGAMI
Kazushiro NAKANO∗1
Hiroo HASEBE∗2∗1∗2

Masato NAKAMURA
Tatsuhiko YOSHIDA∗1
Takeshi MAIE∗2

Temporary Employee
Technical Staﬀ I

Visiting Members
Ken-ici KATO
Toshiyuki MITO (Natl. Inst. Fusion Sci.)
Accelerator Development Group
Group Director
Akira GOTO

307

Members
Toshiko NAKAMURA
Ion Source Team
Team Leader
Akira GOTO
Members
Takahide NAKAGAWA
Masanori KIDERA∗2∗1∗2

Yoshihide HIGURASHI∗1

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Takehiro MATSUSE (Fac. Text. Sci. Technol., Shinshu Univ.)
Accelerator Team
Team Leader
Akira GOTO
Members
Shigeo KOHARA
Osamu KAMIGAITO
Hironori KUBOKI∗∗

Jun-ichi OHNISHI
Naruhiko SAKAMOTO

Junior Research Associate

Visiting Members
Yoshiaki CHIBA
Masatoshi ITO (Cycl. Radioisot. Cen., Tohoku Univ.)
Satoshi KURASHIMA (JAEA, Takasaki)
Lukas STINGELIN (PSI, Switzerland)
Nobumasa MIYAWAKI (JAEA, Takasaki)
Hajime SAITO (SHI Accel. Serv. Ltd.)
Ryoichi WADA (Texas A&M Univ., USA)
Trainees
Takamichi AOKI (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
Masahiro ICHIKAWA (Cycl. Radioisot. Cen., Tohoku Univ.)
Keisuke ITOH (Grad. Sch. Sci. Eng., Saitama Univ.)
Hiroaki MATSUBARA (Grad. Sch. Sci., Osaka Univ.)
Ryo MATSUO (Cycl. Radioisot. Cen., Tohoku Univ.)
Yuji TAMESHIGE (Grad. Sch. Sci. Eng., Osaka Univ.)
Tomohiro TERAZONO (Cycl. Radioisot. Cen., Tohoku Univ.)
Nuclear Physics R & D Group
Group Director
Hiroyoshi SAKURAI
Visiting Members
Hirofumi OHTA (Res. Fac. Cen. Sci. Technol., Univ. Tsukuba)
Trainees
Nozomi SATO (Grad. Sch. Sci. Eng., Tohoku Univ.)308

BigRIPS Team
Team Leader
Hiroyoshi SAKURAI
Members
Toshiyuki KUBO
Atsushi YOSHIDA
Tetsuya OHNISHI∗1
Naoki FUKUDA∗3

Kouichi YOSHIDA
Masao OTAKE
Kensuke KUSAKA∗2
Eri TAKESHITA∗4∗1

Special Postdoctoral Researcher
Contract Researcher∗3
Research Associate∗4
Junior Research Associate∗2Visiting Members
Toshio KOBAYASHI (Grad. Sch. Sci. Fac. Sci., Tohoku Univ.)
Susumu SHIMOURA (CNS)GARIS Team
Team Leader
Hiroyoshi SAKURAI
Members
Kosuke MORITA
Daiya KAJI∗1∗1∗2

Kohji MORIMOTO
Akira YONEDA∗2

Special Postdoctoral Researcher
Contract Technical Scientist

Visiting Members
Shin-ichi GOTO (Niigata Univ.)
Kenji KATORI
Hiroyuki KOURA (JAEA, Tokai)
Hisaaki KUDO (Fac. Sci., Niigata Univ.)
Tetsuya MURAKAMI (Grad. Sch. Sci., Kyoto Univ.)
Toru NOMURA
Keisuke SUEKI (Grad. Sch. Pure Appl. Sci., Univ. Tsukuba)
Fuyuki TOKANAI (Dept. Phys., Yamagata Univ.)
Kenji YOSHINO (Fac. Eng., Miyazaki Univ.)
SLOWRI Team
Team Leader
Yasunori YAMAZAKI
Storage-ring Team
Team Leader
Hiroyoshi SAKURAI
Members
Takashi EMOTO
Tadashi KOSEKI∗

Masanori WAKASUGIYoshitaka YAMAGUCHI∗

Research Associate

Visiting Members
Akira OZAWA (Inst. Phys., Univ. Tsukuba)

309

Polarized RI Beam Team
Team Leader
Koichiro ASAHI
Computing and Network Team
Team Leader
Takashi ICHIHARA
Detector Team
Team Leader
Hideto EN’YO
Application and Development Group
Group Director
Yasushige YANOMembers
Kazuya TAKAHASHI
Shuichi ENOMOTO
Masako IZUMI
Teruyo TSUKADA
Shinji MOTOMURA∗1
Hideki MADOKORO∗2
Hiroyuki SAITO∗2
Narumasa MIYAUCHI∗3
Hideo SHOUJI∗4
Yousuke KANAYAMA∗5

Tomoko ABE
Hiroshige TAKEICHI
Tomoki MATSUYAMA
Hiromitsu HABA
Nguyen DINH DANG∗2
Yuko MOCHIZUKI∗2
Yoshiharu YAMAMOTO∗2
Masako HASAMA∗4
Hiroyuki ICHIDA∗4∗1

Special Postdoctoral Researcher
Contract Researcher∗3
Technical Staﬀ I∗4Part-time Staﬀ I∗5Junior Research Associate∗2Visiting Members
Ryutaro AIDA (Natl. Inst. Floricult. Sci.)
Kazuhiko AKIYAMA (Grad. Sch. Pure Appl. Sci., Univ. Tsukuba)
Ryohei AMANO (Fac. Med., Kanazawa Univ.)
Sachiko AMARI (Washington Univ., USA)
Chang-Hyu BEA (Sunchon Natl. Univ., Korea)
Hiroyuki DAIMON (Osaka Pref. Univ.)
Wenjun DING (Colorado State Univ., USA)
Kazutoyo ENDO (Showa Pharm. Univ.)
Kaori ENOMOTO (Univ. Human Arts Sci.)
Mika FUKUOKA (Tokyo Univ. Fish.)Koji FURUKAWA (Mukoyama Orchids Co., Ltd.)
Yoshiya FURUSAWA (Natl. Inst. Radiol. Sci.)
Toshinari GODO (Botanic Gardens Toyama)
Yasuyuki GONO
Misako HAMATANI (Hiroshima City Agric. Forest. Promot. Cen.)
Yasuhide HARA (Kanagawa Inst. Agric. Sci.)
Masanori HATASHITA (Wakasa Wan Energy Res. Cen.)
Hiroshi HIDAKA (Fac. Sci., Hiroshima Univ.)
Atsushi HIGASHITANI (Grad. Sch. Life Sci., Tohoku Univ.)
Seiichiro HIMENO (Fac. Pharm. Sci., Tokushima Bunri Univ.)
Akiko HOKURA (Fac. Sci., Tokyo Univ. Sci.)
Ichiro HONDA (Natl. Agric. Res. Cen., Min. Agric. Forest. Fish. Japan)
Mitsugu HORITA (Hokkaido Green-bio Inst.)
Takako IKEDA (Showa Women’s Univ.)

310

Hiroko INAGE (Int. Life Sci. Inst.)
Takashi INAMURA
Toshiaki ISHII (Natl. Inst. Radiol. Sci.)
Nobuyoshi ISHII (Natl. Inst. Radiol. Sci.)
Yuji ITO (Natl. Agric. Res. Cent., Hokkaido Region)
Hiroshi KAGAMI (Shizuoka Citrus Exp. Station)
Takeshi KANAYA (Suntory Flowers, Ltd.)Si-Yong KANG (Dep. Rad. Plant Breed. Genet., KAERI, Korea)
Shuichi KIMURA (Grad. Sch. Hum. Life Sci., Showa Woman’s Univ.)
Tomojirou KOIDE (Riken Vitamin Co., Ltd.)
Masuo KONDOH (Showa Pharm. Univ.)
Tsutomu KUBOYAMA (Ibaraki 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.)
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.)
Shoushichi MOTONAGA
Koji MURAI (Fukui Pref. Univ.)
Tomohiro NABEKURA (Fac. Pharm. Sci., Niigata Univ. Pharm. Appl. Life Sci.)
Yuichiro NAGAME (JAEA, Tokai)
Yukiko NAKANISHI (Grad. Sch. Hum. Life Sci., Showa Woman’s Univ.)
Van Chuyen NGUYEN (Jpn. Women’s Univ.)
Yasumitsu OGURA (Grad. Sci. Pharm. Sci., Chiba Univ.)
Mio OHNUMA (Inst. Mol. Cell. Biosci., Univ. Tokyo)
Norihiro OHTSUBO (Natl. Inst. Floricult. Sci.)
Tomo OMIYA (Hokkaido Ornamental Plants Veg. Res. Cen.)
Kenji OSAWA (Nagano Agric. Res. Cen.)
Jun SAITO (Iwatsu Test Instrum. Corp.)
Kouichi SAKAMOTO (JAEA, Takasaki)
Tomofumi SAKURAGI (Natl. Inst. Radiol. Sci.)
Hiromu SAKURAI (Kyoto Pharm. Univ.)
Mutsuko SASAKI
Tadashi SATOU (Grad. Sch. Life Sci., Tohoku Univ.)
Hiroaki SERIZAWA (Nagano Veg. Ornamental Crops Exp. Station)
Takiko SHIMADA (Res. Inst. Agric. Resour., Ishikawa Agric. Coll.)
Hiroshi SHIMIZU (Fac. Sci., Hiroshima Univ.)
Atsushi SHINOHARA (Dept. Chem., Grad Sch. Sci., Osaka Univ.)
Fumio SUGAWARA (Tokyo Univ. Sci.)
Masao SUGIYAMA (Hokko Chem. Ind. Co., Ltd.)
Keita SUGIYAMA (Natl. Inst. Veg. Tea Sci.)
Kazunori SUZUKI (Plant Biotech. Inst. Ibaraki Agric. Cen.)
Kenichi SUZUKI (Suntory Flowers, Ltd.)
Toshihiro SUZUKI (Meiji Pharm. Univ.)
Mikiko SUZUKI (Showa Women’s Univ.)
Kazuo T. SUZUKI (Grad. Sch. Pharm. Sci., Chiba Univ.)
Hiroyuki SUZUKI (RI Res. Cen., Chiba Univ.)
Takahiro TACHIBANA (Waseda High Sch., Waseda Univ.)
Keiko TAGAMI (Natl. Inst. Radiol. Sci.)
Yoshio TAKAHASHI (Grad. Sch. Sci., Hiroshima Univ.)
Masaaki TAKAHASHI (Grad. Sci. Agric. Biol. Sci., Osaka Pref. Univ.)
Miho TAKAHASHI (Tokyo Univ. Fish.)Atsushi TAKEDA (Fac. Pharm. Sci., Univ. Shizuoka)
Haruna TAMANO (Fac. Pharm. Sci., Univ. Shizuoka)
Shinzo TANABE (Meiji Pharm. Univ.)
Teruhiko TERAKAWA (Hokko Chem. Ind. Co., Ltd.)
Tadayasu TOGAWA (Meiji Pharm. Univ.)
Ken TOKUHARA (Dogashima Orchid Cen.)

311

Masanori TOMITA (CRIEPI)Takehiro TOMITANI (Natl. Inst. Radiol. Sci.)
Hisashi TSUJIMOTO (Fac. Agric., Tottori Univ.)
Shigeo UCHIDA (Natl. Inst. Radiol. Sci.)
Kohshin WASHIYAMA (Fac. Medicine, Kanazawa Univ.)
Masao WATANABE (Fac. Agric., Iwate Univ.)
Tokuko WATANABE (Fac. Fish., Tokyo Univ. Fish.)
Shuhei YAMAJI
Mineo YAMASAKI (Nara Med. Univ.)
Makoto YANAGA (Fac. Sci., Shizuoka Univ.)
Hiroyuki YASUI (Kyoto Pharm. Univ)
Takashi YOSHIMURA (Grad. Sch. Sci., Osaka Univ.)
Akihiko YOKOYAMA (Fac. Sci., Kanazawa Univ.)
Shigekazu YONEDA (Natl. Sci. Museum)Takuji YOSHIDA (Takii Seed Co., Ltd.)
Shozo YOSHIDA (Nara Med. Univ.)
Yumin ZHAO (Shanghai Jiao Ting Univ., China)
Trainees
Yusuke ADACHI (Grad. Sch. Pharm. Sci., Kyoto Pharm. Univ.)
Tomoko ANDO (Grad. Sch. Hum. Life Sci., Showa Woman’s Univ.)
Ryoichi HIRAYAMA (Grad. Sch. Sci. Tecnol., Chiba Univ.)
Yoshitaka KASAMATSU (Grad. Sch. Sci., Osaka Univ.)
Yusuke KITAMOTO (Grad. Sch. Sci., Osaka Univ.)
Yoshitaka MATSUMOTO (Grad. Sch. Medicine., Chiba Univ.)
Keiji MATSUO (Grad. Sch. Sci., Osaka Univ.)
Ryuji MINAYOSHI (Grad. Sch. Sci. Techol., Shizuoka Univ.)
Yohei MITSUBORI (Fac. Sci. Tech., Tokyo Univ. Sci.)
Ryoko ONUMA (Fac. Sci., Tokyo Univ. Sci.)
Daisuke SAIKA (Grad. Sch. Sci., Osaka Univ.)
Tomomasa TAKABE (Grad. Sch. Sci., Osaka Univ.)
Yuki TASHIRO (Grad. Sch. Sci., Osaka Univ.)
Atsushi YUMOTO (Grad. Sch. Pharm. Sci., Meiji Pharm. Univ.)
Safety Group
Group Director
Yoshitomo UWAMINO
Members
Shin FUJITA
Hisao SAKAMOTO∗2

Rieko HIRUNUMA∗1
Hiroki MUKAI∗3∗1

Contract Researcher
Contract Technical Scientist∗3
Visiting Contract Oﬃcer∗2

Visiting Members
Koji OISHI (Shimizu Constr. Co., Ltd.)
Cosmic Radiation Laboratory
Head
Kazuo MAKISHIMA
Members
Hiroshi KATO
Yukikatsu TERADA
Mitsuhiro KOHAMA∗∗

312

Special Postdoctoral Researcher

Toru TAMAGAWA
Tatehiro MIHARA

Visiting Members
Yasushi FUKAZAWA (Dept. Phys., Hiroshima Univ.)
Tateo GOKA (JAXA)
Soojing HONG (Dept. Phys., Saitama Univ.)
Yugo KIMOTO (JAXA)
Motohide KOKUBUN (Dept. Phys., Univ. Tokyo)
Tatsuto KOMIYAMA (JAXA)
Haruhisa MATSUMOTO (JAXA)
Hiromasa MIYASAKA (Cal. Inst. Technol., USA)
Motoki NAKAJIMA (Coll. Sci. Technol., Nihon Univ.)
Kazuhiro NAKAZAWA (JAXA)
Yasutomo SASAKI (JAXA)
Tadayuki TAKAHASHI (JAXA)
Kazuhiro TERASAWA (JAXA)
Kazutaka YAMAOKA (Aoyama Gakuin Univ.)
Radiation Laboratory
Head
Hideto EN’YO
Members
Yasuyuki AKIBA
Yuji GOTO
Masahiro OKAMURA
Hiromi SATO
Kiyoshi TANIDA
Kazuaki IKEDA∗1
Ryotaro MUTO∗1
Hiroaki OHNISHI∗1
Masashi OHNO∗1
Hisayuki TORII∗1
Masanori HIRAI∗2
Soichiro KAMETANI∗2
Hiroyuki KAWAMURA∗2
Takahiro MORISHIMA∗2
Munehisa OTANI∗2
Takenao SHINOHARA∗2
Junji TOJO∗2∗1∗2

Takashi ICHIHARA
Itaru NAKAGAWA
Yoshie OTAKE
Atsushi TAKETANI
Yasushi WATANABE
Kenji MISHIMA∗1
Megumi NARUKI∗1
Tetsuya OHNISHI∗1
Hiroyuki TAKEDA∗1
Johann HEUSER∗2
Katsuya HIROTA∗2
Hiroyuki KANO∗2
Akio KIYOMICHI∗2
Yoshiyuki ONUKI∗2
Vladimir L. RYKOV∗2
Kazutaka SUDO∗2
Satoshi YOKKAICHI∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Tomohiro ADACHI (KDN)
Hiroshi AKOH (AIST)
Masahiro AOYAGI (AIST)
Masayuki ASAKAWA (Grad. Sch. Sci., Osaka Univ.)
Kenneth N. BARISH (UCR, USA)
Sasha BAZILVSKY (BNL, USA)
Wolfgang BENTZ (Dept. Phys., Sch. Sci., Tokai Univ.)
Muriel Jane BURWARD-HOY (Dept. Phys., State Univ. New York, Stony Brook, USA)
Mickey CHIU (Dept. Phys., UIUC, USA)
Sanatan DIGAL (Dept. Phys. Grad. Sch. Sci., Univ. Tokyo)
Waled EMAM (UCR, USA)
Frank ELLINGHAUS (Univ. Colorado, USA)
Oleg EYSER (UCR, USA)
Yoshihide FUCHI (KEK)
Hirotsugu FUJII (Grad. Sch. Arts Sci., Univ. Tokyo)
Haruhiko FUNAHASHI (Kyoto Univ.)
Tetsuo HATSUDA (Dept. Phys. Grad. Sch. Sci., Univ. Tokyo)

313

Toshiyuki HATTORI (Tokyo Inst. Technol.)
Hiro HIEIJIMA (UIUC, USA)
Kensuke HOMMA (Fac. Sci., Hiroshima Univ.)
Kenichi IMAI (Fac. Sci., Kyoto Univ.)
Katsuya ISHIGURO (Kanazawa Univ.)
Noriyoshi ISHII (Tokyo Inst. Technol.)
Edward R. KINNEY (Univ. Colorado, USA)
Ming LIU (LANL, USA)Jameson ROBERT (Institut Angewandth Physik, Goethe Universität Frankfurt, Germany)
Osamu JINNOUCHI (KEK)
Masashi KANETA (Grad. Sch. Sci., Tohoku Univ.)
Hirotsugu KASHIWAGI (JAEA)
Yuji KAWABATA (Kyoto Univ.)
Takeo KAWASAKI (Fac. Sci., Niigata Univ.)
Jirou KODAIRA (Fac. Sci., Hiroshima Univ.)
Yuji KOIKE (Fac. Sci., Niigata Univ.)
Sergei KONDORASHEV (ITEP, Russia)
Hidekazu KUMAGAI
Shunzo KUMANO (KEK)
Teiji KUNIHIRO (YITP, Kyoto Univ.)
Masahiko KURAKADO (OECU)
Youngil KWON (Dept. Phys., Seoul Natl. Univ., Korea)
Keisuke MAEHATA (Kyusyu Univ.)
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)
Hiroaki MYOREN (Saitama Univ.)
Shoji NAGAMIYA (KEK)
Kenichi NAITO (Hokkaido Univ.)
Sachio NAITOU (KEK)
Hiroshi NAKAGAWA (AIST)
Shogo NAKAMURA (Fac. Educ., Yokohama Natl. Univ.)
Akio OGAWA (Phys. Dept., BNL, USA)
Takayuki OKU (JAEA)
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.)
Kenji SASAKI (KEK)
Shinya SAWADA (KEK)
Michiko SEKIMOTO (KEK)Toshiaki SHIBATA (Tokyo Inst. Technol.)
Kenta SHIGAKI (Fac. Sci., Hiroshima Univ.)
Shigetomo SHIKI (OECU)
Tatsushi SHIMA (Osaka Univ.)
Hirohiko SHIMIZU (KEK)
Mikhail STEPANOV (Phys. Dept., New Mexico State Univ., USA)
Takanori SUGIHARA (Fac. Sci., Hiroshima Univ.)
Toru SUGITATE (Fac. Sci., Hiroshima Univ.)
Jun-ichi SUZUKI (JAEA)
Tsuneo SUZUKI (Kanazawa Univ.)
Tohru TAINO (Saitama Univ.)
Manobu TANAKA (KEK)
Kazuo TANIGUCHI (OECU)
Satoru TERASHIMA (Fac. Sci., Kyoto Univ.)
Manabu TOGAWA (Fac. Sci., Kyoto Univ.)
Thomas THROWE (Phys. Dept., BNL, USA)
Alexander TITOV (Flerov Lab. Nucl. React., JINR, Russia)

314

Marcus WAGNER (Fac. Sci., Kyoto Univ.)
Satoru YAMADA (JAEA)
Yoshiaki YASUI (Tokyo Manage. Coll.)
Koichi YAZAKI (Tokyo Women’s Chr. Univ.)
Imran YOUNUS (Univ. New Mexico, USA)
Juzo ZENIHIRO (Fac. Sci., Kyoto Univ.)
Trainees
Kazuya AOKI (Fac. Sci., Kyoto Univ.)
Robert BENNETT (Dept. Phys. Astron. State Univ. New York, USA)
Kieran BOYLE (Dept. Phys. Astron. State Univ. New York, USA)
Hisato EGUCHI (Fac. Sci., Niigata Univ.)
Kouhei FUJIWARA (Fac. Sci., Niigata Univ.)
Yoshinori FUKAO (Fac. Sci., Kyoto Univ.)
Ran HAN (Peking Univ., China)
Koichi HASHIMOTO (Kanazawa Univ.)
Yoshimasa HIDAKA (Fac. Sci., Univ. Tokyo)
Takuma HORAGUCHI (Tokyo Inst. Technol.)Yasuyoshi INOUE (Coll. Sci., Rikkyo Univ.)
Taku ITO (Tokyo Inst. Technol.)
Yoshihiko IWAO (Fac. Sci., Kyoto Univ.)
Fukutarou KAJIHARA (CNS)
Takeshi KANESUE (Kyusyu Univ.)
Hiroki KANO (Tokyo Inst. Technol.)
Masahiro KONNO (Inst. Phys., Univ. Tsukuba)
Antonin KRAL (Czech Tech. Univ. Prague, Czech)
Tomas LISKA (Czech Tech. Univ. Prague, Czech)
Kentarou MAWATARI (Fac. Human Develop., Kobe Univ.)
Petr MIKES (Inst. Phys. Prague, Czech)
Koji MIWA (Fac. Sci., Kyoto Univ.)
Astrid MORREALE (UCR, USA)
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.)
Masato NARISAWA (Saitama Univ.)
Hiromi OKADA (Fac. Sci., Kyoto Univ.)
Ikuo OHTA (Kyusyu Univ.)
Shinsuke OOTA (CNS)
Misaki OUCHIDA (Fac. Sci., Hiroshima Univ.)
Kazuhiko SAKAKIBARA (Tokyo Inst. Technol.)
Joseph SEELE (Univ. Colorado, USA)
Toru SEKIDO (Kanazawa Univ.)
Yosuke SERITA (Saitama 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.)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.)
Shota YOSHIMURA (Saitama Univ.)

315

Radioactive Isotope Physics Laboratory
Head
Hiroyoshi SAKURAI
Members
Takashi ICHIHARA
Shunji NISHIMURA
Toshiyuki SUMIKAMA∗
Masayuki YAMAGAMI∗∗

Takashi KISHIDA
Hideaki OTSU
Kanenobu TANAKA∗

Special Postdoctoral Researcher

Visiting Members
Adrian GELBERG (Univ. Koeln., Germany)
Masayuki MATSUO (Fac. Sci., Niigata Univ.)
Takashi NAGATOMO (Inst. Phys., Univ. Tsukuba)
Tetsuo NORO (Fac. Sci., Niigata Univ.)
Hiroyuki OHTA (Inst. Phys., Univ. Tsukuba)
Yuri PENIONZHK (JINR, Russia)
Trainees
Yuhei HASHIZUME (Inst. Phys., Univ. Tsukuba)
Hiroaki MATSUMOTO (Fac. Sci., Kyoto Univ.)
Applied Nuclear Physics Laboratory
Head
Koichiro ASAHI
Members
Yoshio KOBAYASHI
Akihiro YOSHIMI
Daisuke KAMEDA∗∗

Hideki UENO
Tomohito HASEYAMA∗

Special Postdoctoral Researcher

Visiting Members
Minoru ADACHIHisazumi AKAI (Grad. Sch. Sci., Osaka Univ.)
Yasuaki EINAGA (Fac. Sci. Eng., Keio Univ.)
Koji HIGASHIYAMA (Grad. Sch. Sci., Univ. Tokyo)
Norimichi KOJIMA (Grad. Sch. Arts Sci., Univ. Tokyo)
Kenya M. KUBO (Div. Natl. Sci., Int. Chr. Univ.)
Takuya KURAHASHI (Inst. Mol. Sci.)
Jun MIYAZAKI (Grad. Sci., Tokyo Univ. 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 (JAEA, 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.)

316

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
Sounosuke AOKI (Fac. Sci. Technol., Shizuoka Inst. Sci. Technol.)Takamasa ARAI (Fac. Sci., Tokyo Inst. Technol.)Shinya FUKAGAI (Sch. Sci. Eng., Waseda Univ.)
Hideki FUKASAWA (Fac. Sci., Tokyo Univ. Sci.)
Masaki HAYASHI (Sch. Sci. Eng., Waseda Univ.)
Tatsuya HAYASHI (Grad. Sch. Sci. Eng., Waseda Univ.)
Naota HIGAMI (Grad. Sch. Sci. Eng., Waseda Univ.)
Kazuhiro HIRABAYASHI (Grad. Sch. Sci. Eng., Waseda Univ.)
Yuichi HIRAISHI (Sch. Sci. Eng., Waseda Univ.)
Sayaka HORIE (Fac. Sci. Technol., Shizuoka Inst. Sci. Technol.)Takashi IIDA (Sch. Sci. Eng., Waseda Univ.)
Takeshi INOUE (Sch. Sci. Eng., Tokyo Inst. Technol.)
Tomoko KAKUYAMA (Div. Natl. Sci., Int. Chr. Univ.)
Hirokazu KATO (Fac. Sci., Tokyo Univ. Sci.)
Yoshihiro KAWAGUCHI (Div. Natl. Sci., Int. Chr. Univ.)
Hirokazu KAWAMURA (Fac. Sci., Rikkyo Univ.)
Go KIJIMA (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)Hiroshi MATSUBA (Grad. Sch. Sci. Eng., Waseda Univ.)
Yoichi MURAKAMI (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.)
Kentaro NAMIKI (Fac. Sci., Tokyo Univ. Sci.)
Satoshi NISHINO (Fac. Sci. Technol., Shizuoka Inst. Sci. Technol.)Masashi OHKUBO (Grad. Sch. Arts Sci., Univ. Tokyo)
Yoshinori OKADA (Grad. Sch. Sci. Eng., Waseda Univ.)
Sachiko OSHIMA (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)
Guillaume PEDOUSSAUT (Div. Natl. Sci., Int. Chr. Univ.)
Kazumasa SAKATA (Fac. Sci. Technol., Shizuoka Inst. Sci. Technol.)
Chika SUGI (Grad. Sch. Sci. Eng., Waseda Univ.)
Kunifumi SUZUKI (Fac. Sci. Technol., Shizuoka Inst. Sci. Technol.)Shota SUZUKI (Fac. Sci. Technol., Shizuoka Inst. Sci. Technol.)
Kaori TAGUCHI (Grad. Sch. Sci., Tokyo Metrop. Univ.)
Kenichi TAKASE (Sch. Sci. Eng., Tokyo Inst. Technol.)Akiko TAKEBAYASHI (Sch. Sci. Eng., Waseda Univ.)
Makoto TAKEMURA (Fac. Sci., Tokyo Inst. Technol.)Yoji TURUOKA (Div. Natl. Sci., Int. Chr. Univ.)
Toru YOSHIDA (Sch. Sci. Eng., Waseda Univ.)
Atomic Physics Laboratory
Head
Yasunori YAMAZAKI
Members
Tadashi KAMBARA
Hitoshi OYAMA
Takao M. KOJIMA
Takane KOBAYASHI
Masaki OURA
Naofumi KURODA∗1
Tarek Ali Mohamed HASSAN∗1

Yasuyuki KANAI
Michiharu WADA
Yoichi NAKAI
Tokihiro IKEDA
Yoshihisa ISHIDA∗1
Takashi NAKAMURA∗1
Hiroyuki TANAKA∗1317

Masahiro SHIBATA∗2
Yoshio IWAI∗3

Haruhiko SAITOH∗2∗1

Contract Researcher
Special Postdoctoral Researcher∗3Part-time staﬀ supporting research∗2

Visiting Members
Kozo ANDO
Yohko AWAYA (Coll. Art Design Gen. Ed., Musashino Art Univ.)
Toshiyuki AZUMA (Dept. Phys., Tokyo Metrop. Univ.)
Daniel BARNA (KFKI, Hungary)
Joachim BURGDÖRFER (Vienna Univ. Technol., Austria)
Yasuhiro CHIMI (Tokai Res. Estab., JAEA)
Jörg EICHLER (Hahn-Meiter-Inst. Berlin, Germany)
Makoto C. FUJIWARA (TRIUMF, Canada)
Atsushi HATAKEYAMA (Grad. Sch. Arts Sci., Univ. Tokyo)
Akira HITACHI (Kochi Med. Sch.)
Masamitsu HOSHINO (Dept. Phys., Sophia Univ.)
Atsushi ICHIMURA (Inst. Space Astro. Sci.)
Akinori IGARASHI (Fac. Eng., Miyazaki Univ.)
Hideki IIMURA (JAEA)
Norito ISHIKAWA (Tokai Res. Estab., JAEA)
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)
Chikara KONDOU (Dept. Phys., Grad. Sch. 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.)
Akihiro MOHRI
Kanetada NAGAMINE (Inst. Mater. Struc. Sci., KEK)
Nobuyuki NAKAMURA (Inst. Laser Sci., Univ. Electro-Commun.)
Tetsuya NAKAZAWA (Tokai Res. Estab., JAEA)
Takuya NEBIKI (Kochi Univ. Technol.)Shunsuke OHTANI (Inst. Laser Sci., Univ. Electro-Commun.)
Kunihiro OKADA (Fac. Sci. Technol., Sophia Univ.)
Satoru OKAYASU (Tokai Res. Estab., JAEA)
Brian O’ROURKE (JSPS)
Fumihisa ONO (Fac. Sci., Okayama Univ.)
Nagayasu OSHIMA (AIST)
Patrice PEREZ (C.E.A. Saclay, France)
Lukas PICHL (Found. Comput. Sci. Lab., Univ. Aizu)
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
Nikolaus STOLTERFOHT (Hahn-Meitner-Institut Berlin GmbH, Germany)
Hiroya SUNO (NIFS)
Aiko TAKAMINE (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)

318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.)
Victor VARENTSOV (V. G. Khlopin Radium Inst., Russia)
Tienshan WANG (Lanzhou Univ., China)
Tsutomu WATANABE
Hermann WOLLNIK (Giessen Univ., Germany)
Akira YAGISHITA (KEK)
Nobuhiro YAMANAKA (Sch. Sci., Univ. Tokyo)
Yaming ZOU (Fudan Univ., China)
Trainees
Jacques BABAUD (Appl. Phys., Ecole Centrale Paris, France)
Yoshinori ENOMOTO (Coll. Art Sci., Univ. Tokyo)
Masafumi FUKUZUMI (Grad. Sch. Eng., Osaka Pref. Univ.)
Guillaume JEGOU (Inst. Nucl. Phys., Univ. Paris-Sud Orsay, France)
Vladimir LIOUBIMOV (Texas A&M Univ., USA)
Nobuhiro MAEDA (Grad. Sch. Eng., Osaka Pref. Univ.)
Yasuharu MITSUDA (Chem., Univ. Electro-Commun.)Yuji MIYAMOTO (Grad. Sch. Sci. Eng., Sophia Univ.)
Yugo NAGATA (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
Yuji NAKANO (Dept. Phys., Tokyo Metrop. Univ.)
Koremitsu OGATA (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
Shigeki SHIBATA (Dept. Appl. Phys. Chem., Univ. Electro-Commun.)
Heavy Ion Nuclear Physics Laboratory
Head
Tohru MOTOBAYASHIMembers
Toshimi SUDA
Yasushi WATANABE
Akihisa KOHAMA
Yoshiyuki YANAGISAWA
Masaaki TAKASHINA∗1
Kazunari YAMADA∗1
Takuma MATSUMOTO∗1
Shawn BISHOP∗2
Meiko UESAKA-KUROKAWA∗2
Mitsutaka YAMAGUCHI∗2∗1∗2

Alexei A. KORSHENINNIKOV
Yukari MATSUO
Nori AOI
Ken-ichirou YONEDA
Satoshi TAKEUCHI∗1
Hidetada BABA∗1
Shinichiro MICHIMASA∗1
Kiyomi IKEDA∗2
Kimiko SEKIGUCHI∗2
Toshimitsu YAMAZAKI∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Yasuhisa ABE (Yukawa Inst. Theor. Phys., Kyoto Univ.)
Yasuo AOKI (Inst. Phys., Univ. Tsukuba)
Shigeyoshi AOYAMA (Fac. Sci., Niigata Univ.)
Ichiro ARAI (Univ. Tsukuba)
Yoshihiro ARITOMO (JINR, Russia)
Daniel BAZIN (Michigan State Univ., USA)
Didier BEAUMEL (IPN-Orsay, France)
Francis A. BECK (CRN-Strasbourg, France)
Mottelson R BEN (NORDITA, Denmark)
Geoge BERG (Univ. Notre Dame, USA)
Yorick BLUMENFIELD (IPN-Orsay, France)
Alan CHEN (McMaster Univ., Canada)
Silvio CHERUBINI (Katania Univ., Italy)319

Marco LA COGNATA (Katania Univ., Italy)
Tien Khoa DAO (Inst. Nucl. Sci. Tech., China)
Zsolt DOMBRADI (Inst. Nucl. Res., Hung. Acad. Sci., Hungary)
Zoltan ELEKES (Inst. Nucl. Res., Hung. Acad. Sci., Hungary)
Yoshiko EN’YO (Kyoto Univ.)
Henning ESBENSEN (Argonne Natl. Lab., USA)
Michel FAMIANO (Michigan State Univ., USA)
Hubert FLOCARD (IPN-Orsay, France)
Yoshihide FUCHI (KEK)
Shinichiro FUJII (Grad. Sch. Sci., Univ. Tokyo)
Yoshitaka FUJITA (Grad. Sch. Sci., Osaka Univ.)
Mamoru FUJIWARA (RCNP, Osaka Univ.)
Tomonori FUKUCHI (Coll. Sci., Rikkyo Univ.)
Mitsunori FUKUDA (Grad. Sch. Sci., Osaka Univ.)
Zsolt FÜLÖP (Inst. Nucl. Res., Hung. Acad. Sci., Hungary)Ken-ichi FUSHIMI (Tokushima Univ.)
Zoltan GACSI (ATOMKI, Hungary)
Yu-Cheng GE (Peking Univ., China)
Vardir GUIMARAES (Univ. Sao Paulo, Brazil)
Hideki HAMAGAKI (Grad. Sch. Sci., Univ. Tokyo)
Jun HASEGAWA (Fac. Sci., Tokyo Inst. Technol.)
Jianjun HE (Grad. Sch. Sci., Univ. Tokyo)
Satoru HIRENZAKI (Fac. Sci., Nara Women’s Univ.)
Khiem LE HONG (Inst. Phys., Natl. Cen. Sci. Technol., Vietnam)
Shen HONG (Dept. Phys., Nankai Univ., China)
Michio HONMA (Aizu Univ.)
TakatoshiI HORIBATA (Fac. Sci., Aomori Univ.)
Hisashi HORIUCHI (Grad. Sch. Sci., Kyoto Univ.)
Hui HUA (Michigan State Univ., USA)
Munetake ICHIMURA (Univ. Air)
Eiji IDEGUCHI (Grad. Sch. Sci., Univ. Tokyo)
Kazuo IEKI (Coll. Sci., Rikkyo Univ.)
Nobuaki IMAI (KEK)
Shigeru ISHIMOTO (KEK)
Hironobu ISHIYAMA (KEK)
Naoyuki ITAGAKI (Grad. Sch. Sci., Univ. Tokyo)
Makoto ITO (Fac. Sci., Univ. Tsukuba)
Akira IWAMOTO (JAEA)
Naohisa IWASA (Grad. Sch. Sci., Tohoku Univ.)
Hironori IWASAKI (Grad. Sch. Sci., Univ. Tokyo)
Takuji IZUMIKAWA (Fac. Sci., Niigata Univ.)
Gal JANOS (ATOMKI, Hungary)
Dang-Xing JIANG (Peking Univ., China)
Lee JU (Chung-Ang Univ., Korea)
Toshiki KAJINO (Natl. Astron. Obs.)
Nasser KALANTAR (Univ. Groningen, The Netherlands)
Gabor KALINKA (ATOMKI, Hungary)
Shoko KANNO (Coll. Sci., Rikkyo Univ.)
Kiyoshi KATO (Grad. Sch. Sci., Hokkaido Univ.)
Seigo KATO (Yamagata Univ.)
Takahiro KAWABATA (Grad. Sch. Sci., Univ. Tokyo)
Paul KIENLE (Tech. Univ. Muenchen, Germany)
Takashi KIKUCHI (Utsunomiya Univ.)
Jang Chan KIM (Chung -Ang Univ., Korea)
Ong Chan KIM (Seoul Univ., Korea)
Kikuo KIMURA (Fac. Sci., Nagasaki Inst. Appl. Sci.)
Koichi KINO (Grad. Sch. Sci., Univ. Tokyo)
Tetsuro KOMATSUBARA (Univ. Tsukuba)
Evgueni KOUZMINE (Kurchatov Inst., Russia)
Attila KRASZNAHORKAY (ATOMKI, Hungary)320

Shigeru KUBONO (Grad. Sch. Sci., Univ. Tokyo)
Kazuyoshi KURITA (Coll. Sci., Rikkyo Univ.)
Rubens LICHTENTH (Univ. Sao Paulo, Brazil)
Guan-Hua LIU (Inst. Modern Phys., China)
William LYNCH (Michigan State Univ., USA)
Kazushige MAEDA (Grad. Sch. Sci., Tohoku Univ.)
Yukishige MAEDA (Grad. Sch. Sci., Univ. Tokyo)
Tomohiro MARUNO (Grad. Sch. Sci., Univ. Tokyo)
Kensaku MATSUTA (Grad. Sch. Sci., Osaka Univ.)
Kenichi MATSUYANAGI (Grad. Sch. Sci., Kyoto Univ.)
Jie MENG (Peking Univ., China)
Alberto MENGONI (ENEA, Italy)
Johannes MESSCHENDORP (Univ. Groningen, The Netherlands)
Mototugu MIHARA (Grad. Sch. Sci., Osaka Univ.)
Toshiyuki MINEMURA (KEK)
Shiro MITARAI (Grad. Sch. Sci., Kyusyu Univ.)
Tomoko MIYAGISHI (NIRS)
Yasuo MIYAKE (Inst. Phys., Univ. Tsukuba)
Hiroari MIYATAKE (KEK)
Hiroshi MIZOI (Osaka Electro-Commun. Univ.)
Takahiro MIZUSAKI (Grad. Sch. Sci., Univ. Tokyo)
Peter MOLLER (Los Alamos Natl. Lab., USA)
Sadao MOMOTA (Kochi Univ. Technol.)
Ben MOTTELSON (NORDITA, Denmark)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)
Shintaro NAKAYAMA (Tokushima Univ.)
Evgueni NIKOLSKI (Kurchatov Inst., Russia)
Masahiro NOTANI (Argonne National Lab., USA)
Atsuko ODAHARA (Fac. Sci., Osaka Univ.)
Alexei A. OGLOBLIN (Kurchatov Inst., Russia)
Yukimitsu OHSHIRO (Grad. Sch. Sci., Univ. Tokyo)
Masahisa OHTA (Fac. Sci., Konan Univ.)
Hideaki OHTSU (Fac. Sci., Tohoku Univ.)
Takashi OHTSUBO (Fac. Sci., Niigata Univ.)
Hiroyuki OKAMURA (Grad. Sch. Sci., Tohoku Univ.)
Takeo ONISHI (Grad. Sch. Sci., Univ. Tokyo)
Christian OUELLET (McMaster Univ., Canada)
Kazuhiro OYAMATSU (Aichi Shukutoku Univ.)
Kyoichiro OZAWA (Grad. Sch. Sci., Univ. Tokyo)
Kazutaka OZEKI (CYRIC., Tohoku Univ.)
Jonathan PEARSON (McMaster Univ., Canada)
Yuri PENIONZHK (McMaster Univ., Canada)
P. A. Aloy PERERA (Univ. Kalaniya, Sri Lanka)
Gianluca PIZZONE (Katania Univ., Italy)
Chilakamarri RANGACHARYULU (Univ. Saskatchewan, Canada)
Keirin RIKU (Grad. Sch. Sci., Kyushu Univ.)
Hiroyuki SAGAWA (Univ. Aizu)
Aketo SAITO (Grad. Sch. Sci., Univ. Tokyo)
Harutaka SAKAGUCHI (Grad. Sch. Sci., Kyoto Univ.)
Takao SAKAGUCHI (Grad. Sch. Sci., Univ. Tokyo)
Hideyuki SAKAI (Grad. Sch. Sci., Univ. Tokyo)
Mitsuo SAKAI (Grad. Sch. Sci., Univ. Tokyo)
Yoshinori SAKURAGI (Fac. Sci., Osaka City Univ.)
Kimikazu SASA (Univ. Tsukuba)
Yoshiteru SATOU (Fac. Sci., Tokyo Inst. Technol.)321

Ryoichi SEKI (Cal. State Univ., Northridge, USA)
Noritaka SHIMIZU (Grad. Sch. Sci., Univ. Tokyo)
Yoshifumi SHIMIZU (Grad. Sch. Sci., Kyushu Univ.)
Toru SHIMOURA (Grad. Sch. Sci., Univ. Tokyo)
Cosimo SIGNORINI (INEN, Italy)
Dorottya SOHLER (ATOMKI, Hungary)
Andreas STOLZ (Michigan State Univ., USA)
Takashi SUGIMOTO (Fac. Sci., Tokyo Inst. Technol.)
Kohsuke SUMIYOSHI (Numazu Coll. Technol.)Akihiro SUZUKI (Suzuki Corp.)
Masaru SUZUKI (Grad. Sch. Sci., Univ. Tokyo)
Shoji SUZUKI (KEK)
Takeshi SUZUKI (Saitama Univ.)
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.)
Masatoshi TAKANO (Sci. Eng. Res. Lab., Waseda Univ.)
Noboru TAKIGAWA (Fac. Sci., Tohoku Univ.)
Tadaaki TAMAE (Grad. Sch. Sci., Tohoku Univ.)
Atsushi TAMII (RCNP, Osaka Univ.)
Kazuko TANABE (Otsuma Women’s Univ.)
Masahiko TANAKA (KEK)
Takashi TERANISHI (Grad. Sch. Sci., Kyusyu Univ.)
Jun TERASAKI (Univ. North Carolina, USA)
Mariko TERASAWA (Grad. Sch. Sci., Univ. Tokyo)
Manyee TSANG (Michigan State Univ., USA)
Tomohiro UESAKA (Grad. Sch. Sci., Univ. Tokyo)
Yutaka UTSUNO (Tokai Res. Estab., JAEA)Peter Von BRENTANO (Inst. Kern Phys., Univ. Koeln, Germany)
Takahiro WADA (Fac. Sci., Konan Univ.)
Tomotugu WAKASA (Grad. Sch. Sci., Kyusyu Univ.)
Takashi WAKUI (Tohoku Univ.)
Shinichi WATANABE (Grad. Sch. Sci., Univ. Tokyo)
Yuu WATANABE (KEK)
Shuwei XU (Inst. Modern Phys., Chin. Acad. Sci., China)
Kazuhiro YABANA (Fac. Sci., Niigata Univ.)
Kentarou YAKOU (Grad. Sch. Sci., Univ. Tokyo)
Hidetoshi YAMAGUCHI (Grad. Sch. Sci., Univ. Tokyo)
Takayuki YAMAGUCHI (Fac. Sci., Saitama Univ.)
Shoichi YAMAYA (Grad. Sch. Sci., Univ. Tokyo)
Norio YAMAZAKI (Grad. Sch. Sci., Univ. Tokyo)
Yanlin YE (Peking Univ., China)
Blumenfeld YORICK (IPN-Orsay, France)
Naotaka YOSHINAGA (Fac. Sci., Saitama Univ.)
Yong ZHENG (Grad. Sch. Sci., Univ. Tokyo)
Shan-Gi ZHOU (Peking Univ., China)
Trainees
Takeshi AIBA (Fac. Sci., Niigata Univ.)
Guilherme AMADIO (Grad. Sch. Sci., Univ. Tokyo)
Yoki ARAMAKI (Grad. Sch. Sci., Univ. Tokyo)
Jonathan Michael COOK (Michigan State Univ., USA)
Pham N. DINH (Michigan State Univ., USA)
Natsumi ENDO (Fac. Sci., Tohoku Univ.)
Hisashi FUJIKAWA (Grad. Sch. Sci., Univ. Tokyo)
Hiroki FUJIWARA (Fac. Sci., Osaka Univ.)
Tomonori FUKUCHI (Coll. Sci., Rikkyo Univ.)
Toshiaki FUKUI (Kyoto Univ.)322

Yasuro FUNAKI (Fac. Sci., Kyoto Univ.)
Takeshi FURUKAWA (Fac. Sci., Osaka Univ.)
Taku GUNJI (Grad. Sch. Sci., Univ. Tokyo)
Ryosuke HADATE (Coll. Sci., Rikkyo Univ.)
Yoshiko HASHIMOTO (Fac. Sci., Tokyo Inst. Technol.)Naho HOKOIWA (Fac. Sci., Kyushu Univ.)
Takeshi HOYA (Coll. Sci., Rikkyo Univ.)
Yuichi ICHIKAWA (Grad. Sch. Sci., Univ. Tokyo)
Kiyohiko INAFUKU (Grad. Sch. Sci., Tohoku Univ.)
Kazuhiro ISHIKAWA (Fac. Sci., Tokyo Inst. Technol.)Tadaaki ISOBE (Grad. Sch. Sci., Univ. Tokyo)
Tatsuhiro ITO (Meiji Univ.)
Ikuko KANAZAWA (Fac. Sci., Saitama Univ.)
Tomomi KATO (Fac. Sci., Niigata Univ.)
Tomomi KAWAHARA (Toho Univ.)
Shoko KAWAI (Coll. Sci., Rikkyo Univ.)
Yoshie KAWAMURA (Fac. Sci., Niigata Univ.)
Aram KIM (Ewha Women’s Univ., Korea)
Jang Youl KIM (Chung Ang Univ., Korea)
Mituhisa KITAYAMA (Fac. Sci., Tohoku Univ.)
Kei KOBAYASHI (Fac. Sci., Saitama Univ.)
Mari KOMURO (Fac. Sci., Saitama Univ.)
Yousuke KONDOU (Fac. Sci., Tokyo Inst. Technol.)
Ryo KOYAMA (Fac. Sci., Niigata Univ.)
Hironori KUBOKI (Grad. Sch. Sci., Univ. Tokyo)
Takamasa KUBOKI (Fac. Sci., Saitama Univ.)
Shinichi KUMASHIRO (Fac. Sci., Osaka Univ.)
Chie KUROKAWA (Fac. Sci., Hokkaido Univ.)
Michitarou KUSAKA (Fac. Sci., Tohoku Univ.)
Young Kwan KWON (Chung-Ang Univ., Korea)
Ju Hahn LEE (Chung-Ang Univ., Korea)
Tomohiro MACHIDA (Coll. Sci., Rikkyo 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.)
Kenjiro MIKI (Grad. Sch. Sci., Univ. Tokyo)
Toshiya MIKI (Fac. Sci., Tohoku Univ.)
Kazutaka MIYAKAWA (Fac. Sci., Univ. Tsukuba)
Michal MOCKO (Michigan State Univ., USA)
Tetsuaki MORIGUCHI (Coll. Sci., Rikkyo Univ.)
Kensuke MORIMOTO (Coll. Sci., Rikkyo Univ.)
Konomi MURAKAMI (Fac. Sci., Saitama Univ.)
Takumi NAKABAYASHI (Fac. Sci., Tokyo Inst. Technol.)Shinpei NAKAJIMA (Fac. Sci., Saitama Univ.)
Atsushi NAKAMURA (Fac Sci., Saitama Univ.)
Ryoko NAKAMURA (Coll. Sci., Rikkyo Univ.)
Taro NAKAO (Grad. Sch. Sci., Univ. Tokyo)
Hiroyuki NAKAYAMA (Grad. Sch. Sci., Univ. Tokyo)
Khai Tuan NGUYEN (Hanoi Univ., Vietnam)
Jun NIKURA (Grad. Sch. Sci., Univ. Tokyo)
Haruki NISHINO (Grad. Sch. Sci., Univ. Tokyo)
Shunpei NOJI (Grad. Sch. Sci., Univ. Tokyo)
Susumu ODA (Grad. Sch. Sci., Univ. Tokyo)
Masafumi OIZUMI (Grad. Sch. Sci., Univ. Tokyo)
Naoto OKAICHI (Fac. Sci., Tokyo Inst. Technol.)323

Takashi OKUDA (Fac. Sci., Tohoku Univ.)
Toshifumi OKUMURA (Fac. Sci., Tokyo Inst. Technol.)
Hooi Jin ONG (Grad. Sch. Sci., Univ. Tokyo)
Yosiho OTA (Meiji Univ.)
Andrew ROGERS (Michigan State Univ., USA)
Hiroshi SAENMA (Grad. Sch. Sci., Univ. Tokyo)
Shota SAITO (Grad. Sch. Sci., Univ. Tokyo)
Takaaki SAITO (Grad. Sch. Sci., Univ. Tokyo)
Satoshi SAKAGUCHI (Grad. Sch. Sci., Univ. Tokyo)
Hazuki SAKAI (Coll. Sci., Rikkyo Univ.)
Takashi SAKO (Grad. Sch. Sci., Univ. Tokyo)
Tomoyuki SAKURADA (Coll. Sci., Rikkyo Univ.)
Satoshi SANO (Waseda Univ.)
Makoto SASAKI (Fac. Sci., Osaka Univ.)
Ryoko SASAMOTO (Grad. Sch. Sci., Univ. Tokyo)
Masaki SASANO (Grad. Sch. Sci., Univ. Tokyo)
Tadanori 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.)
Ryoko SHINODA (Fac. Sci., Saitama Univ.)
Mayuko 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.)
Naohiro TAKEMOTO (Fac. Sci., Saitama Univ.)
Hideki TANAKA (Fac. Sci., Niigata Univ.)
Tasutaka TANIGUCHI (Grad. Sch. Sci., Kyoto Univ.)
Yasuo UEKI (Coll. Sci., Rikkyo Univ.)
Hirotaka UENO (Coll. Sci., Rikkyo Univ.)
Yasuo WAKABAYASHI (Fac. Sci., Kyushu Univ.)
Mark WALLACE (Michigan State Univ., USA)
Kiwamu WATANABE (Fac. Sci., Tohoku Univ.)
Yorito YAMAGUCHI (Grad. Sch. Sci., Univ. Tokyo)
Yuzo YAMAMOTO (Coll. Sci., Rikkyo Univ.)
Takuma YASUNO (Fac. Sci., Univ. Tsukuba)
Michiori YOSHITAKE (Fac. Sci., Saitama Univ.)
Advanced Meson Science Laboratory
Head
Masahiko IWASAKIMembers
Teiichiro MATSUZAKI
Haruhiko OUTA
Yasuyuki MATSUDA
Hiroaki OHNISHI
Shinji OKADA∗1
Takatoshi SUZUKI∗1
Seiko OHIRA∗2

324

Katsuhiko ISHIDA
Isao WATANABE
Kenta ITAHASHI
Takahisa KOIKE∗1
Hidekatsu NEMURA∗1
Dai TOMONO∗1
Pavel BAKULE∗2

Takao SUZUKI∗2∗1∗2

Masami IIO∗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. Exper. 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.)
Masahira HIRANO (JST)Emiko HIYAMA (Fac. Sci., Nara Women’s Univ.)
Susumu IKEDA (KEK)
Yutaka IKEDO (Toyota Central R&D Labs.)
Shigeru ISHIMOTO (KEK)
Tomoichi ISHIWATARI (Stefan Meyer Inst., Austria)
Atsuko ITO
Ryosuke KADONO (KEK)
Masayasu KAMIMURA
Mineo KATO (Tokai Res. Estab. Dev. Cen., JAEA)
Naritoshi KAWAMURA (KEK)
Jungho KIM (Seoul Natl. Univ., Korea)
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.)
Satoru MATSUISHI (Front. Collab. Res. Cen., Tokyo Inst. Technol.)
Yasuhiro MIYAKE (KEK)
Soichiro MIZUSAKI (Coll. Sci. Eng., Aoyama Gakuin Univ.)
Kazuhiko MUKAI (Toyota Central R&D Labs.)
Khin Swe MYINT (Mandalay Univ., Myanmar)
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)
Hiroshi NOZAKI (Toyota Central R&D Labs.)
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. Dev. Cen., JAEA)
Ryoichi SEKI (Cal. State Univ., Northridge, USA)
Koichiro SHIMOMURA (KEK)
Patrick STRASSER (KEK)325

Hiroyuki SUGAI (Tokai Res. Estab. Dev. Cen., JAEA)
Jun SUGIYAMA (Toyota Central R&D Labs.)
Haruhiko SUZUKI (Grad. Sch. Nat. Sci. Technol., Kanazawa Univ.)
Kazuyuki TAKAI (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)
Keiji TAKEDA (Res. Inst. Electron. Sci., Hokkaido Univ.)
Hiroyuki TANAKA (Univ. Cal., Riverside, USA)
Akihiko TANIGUCHI (KURRI, Kyoto Univ.)
Takashi TANIGUCHI (Coll. Sci. Eng., Aoyama Gakuin Univ.)
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.)
Arkady A. YUKHIMCHUK (Russ. Fed. Nucl. Cen., Russia)
Johann ZMESKAL (Stefan Meyer Inst., Austria)
Trainees
Hiroshi ABURANO (Grad. Sch. Nat. Sci. Technol., Kanazawa Univ.)
Soichiro ARIMURA (Grad. Sch. Sci., Osaka Univ.)
Truong Cong DUAN (Grad. Sch. Sci., Osaka Univ.)
Ken GOTO (Grad. Sch. Sci., Osaka Univ.)
Kenichi HACHITANI (Grad. Sch. Sci., Chiba Univ.)
Toshio HANAKI (Grad. Sch. Fac. Sci. Technol., Tokyo Univ. Sci.)
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.)
Jun MATSUMOTO (Fac. Sch. Sci., Osaka 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)
Toshiaki TAKAGI (Grad. Sch. Sci., Tohoku Univ.)
Katsunori TAKAHARA (Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)
Hideyuki TATSUNO (Grad. Sch. Sci., Univ. Tokyo)
Yoshitake TODA (Inter. Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)
Yoko TOMITA (Grad. Sch. 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
Hiroko KATORI
Tetsuo HANAGURI
Jobu MATSUNO
Seiji NIITAKA∗1
Ayako YAMAMOTO∗2∗1∗2

Hiroki YAMAZAKI
Koshi TAKENAKA
Katsuya IWAYA∗1
Noriko TSUBOI∗1
Petra JONSSON∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Masaaki MATSUDA (JAEA)
Hirokazu TSUNETSUGU (Yukawa Inst. Theor. Phys., Kyoto Univ.)
Kunimitsu UCHINOKURA

326

Trainees
Hideo NISHIKUBO (Dept. Superconduct., 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
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 (JAEA)
Masami WATANABE (Radiat. Life Sci. Res. Reactor Inst., Kyoto Univ.)
Shoji YAMASHITA (Natl. Saitama Hosp.)
ADVANCED DEVELOPMENT AND SUPPORTING CENTER
Beam Application Team
Head
Takashi MEGURO
Members
Tomohiro KOBAYASHI
Kowashi WATANABE

Aiko NAKAORESEARCH UNIT
Image Information Research Unit (∼ 2005. 11. 15)
Head
Hirohiko M. SHIMIZU
Members
Hiromi SATO
Kazuaki IKEDA∗1
Masashi OHNO∗1
Takahiro MORISHIMA∗2∗1∗2

Seiichiro ARIYOSHI∗1
Kenji MISHIMA∗1
Katsuya HIROTA∗2
Takenao SHINOHARA∗2

Special Postdoctoral Researcher
Contract Researcher

Visiting Members
Tomohiro ADACHI (Daiichi-kiden Co.)
Haruhiko FUNAHASHI (Dept. Phys., Kyoto Univ.)
Masahiko KURAKADO (Dept. Electr. Appl. Phys., Osaka Electro-Commun. Univ.)
Hiroaki MYOREN (Fac. Eng., Saitama Univ.)
Takayuki OKU (JAEA)
Shigetomo SHIKI (Dept. Electr. Appl. Phys., Osaka Electro-Commun. Univ.)
Junichi SUZUKI (JAEA)
Tatsushi SHIMA (RCNP, Osaka Univ.)
Tohru TAINO (Fac. Eng., Saitama Univ.)327

Satoru YAMADA (JAEA)
Trainees
Masato NARISAWA (Dept. Electr. Syst., Saitama Univ.)
Yosuke SERITA (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
Takashi ICHIHARA
Yasuyuki AKIBA
Yuji GOTO
Kiyoshi TANIDA
Douglas Edward FIELDS∗1
Masashi KANETA∗2
Osamu JINNOUCHI∗2
Junkichi ASAI∗3
David KAWALL∗1

Yasushi WATANABE
Atsushi TAKETANI
Itaru NAKAGAWA
Abhay DESHPANDE∗1
Matthias GROSS PERDEKAMP∗1
Tsuguchika TABARU∗3
Kensuke OKADA∗2
Wei XIE∗4
Nobuyuki KAMIHARA∗3

Visiting Members
Yoshinori FUKAO (Kyoto Univ.)
Takuma HORAGUCHI (Tokyo Inst. Technol.)Naohito SAITO (Kyoto Univ.)
Zheng LEE (BNL, USA)
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
Thomas SCHAEFER∗1
Ubirajara van KOLCK∗1
Werner VOGELSANG∗4
Sinya AOKI∗1
Takeshi YAMAZAKI∗2
Takumi DOI∗3
Shoichi SASAKI∗4328

Christopher DAWSON∗4
Thomas BLUM∗4
Stefan KRETZER∗2
Takanori SUGIHARA∗3
Peter PETRECZKY∗4
Taku IZUBUCHI∗1
Kei IIDA∗4
Yoshitaka HATTA∗3
Feng YUAN∗1
Kenji FUKUSHIMA∗3

Ägnes MÖCSY∗2
Kirill TUCHIN∗1

Denes MOLNAR∗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)
Ralf-Christian SEIDL (Univ. Illinois, USA)
∗1
∗3

RHIC Physics Fellow, ∗2 Research Associate,
Special Postdoctoral Researcher, ∗4 RIKEN BNL Fellow

329

AUTHOR INDEXABE Tomoko

阿部知子

89, 133, 134, 135, 136, 137,BISHOP Shawn

138, 139, 140, 141, 142, 245

BLUMENFELD Yorick

43, 44, 53, 55, 59, 71, 143

AIHARA Toshimitsu

藍原利光

3, 229BOOSE Stephan

AKAISHI Yoshinori

赤石義紀

34

BOWEN Matt D.

AKIBA Yasuyuki

AKIMURA Yuka

秋村友香

BOYLE Kieran

193, 194, 195, 199, 200,

BOYLE Peter A.

203, 205, 207, 209, 211,

BRAVAR Alessandro

212, 214

BROOKS Melynda

35

BROWN B. Alex

178, 197, 198

AKIYAMA Takahiro

秋山隆宏

76, 110BUNCE GerryAKIYOSHI Hiromichi

秋吉啓充

42, 47BUTSYK Sergey

ALBATAINEH Hisham M.
ALEKSEEV Igor
AMANO Junji

177

186

ALONSO Jose R.

67

AMANO Ryohei

121, 122

天野良平

ANDO Koichi

安藤興一

132

ANDO Kozo

安藤剛三

101

174
178
22

186
189, 193, 194
72

CHAKRABARTI Alok

65

174

CHIBA Akiko

千葉明子

67

CHIBA Satoshi

千葉 敏

35

CHIBA Toshiya

千葉利哉

235

千葉好明

235

CHIBA Yoshiaki

安藤智子

115

CHIU Mickey

ANDO Yoshiaki

安藤嘉章

66

CHRIST Norman H.

AOI Nori

考

ANDO Tomoko
青井

AOKI Kazuya
AOKI Sinya

ARAI Takamasa

52, 54, 56, 57, 58, 61, 62, 63, 65,

CLOET Ian C.

37

66, 71, 72

COHEN Saul D.

174

179, 198, 220
173
246

新井崇雅

69, 70, 90, 91, 145, 155, 156
24

ARUMUGAM Paramasivan

COOK Jhonathan M.

28

DAVID Gabor

187, 197, 198, 199, 203, 212

DHAWAN Satish

186

68, 69, 70, 73, 90, 91, 128,

DIGAL Sanatan

165

145, 154, 155, 156

DINCA Dan.-Christian72

199, 200, 203, 205, 207, 209,

DINH DANG Nguyen

27, 28浅井淳吉

211, 212, 214

DION Alan

ASAI Keisuke

浅井圭介

93, 94

DOI Takumi

耕一郎

AVERBECK Ralf

189, 193, 194

AZUMA Toshiyuki

東 俊行

86

194
土井琢身

DOMBRÁDI Zsolt
DONG Zhihua

48, 50, 53

174

EATON Gordon H.

82, 8356, 57, 60, 61, 62, 63, 64,

EGAMI Tomoaki

江上智晃

66, 71, 74, 75, 150

ELEKES Zoltán48, 50, 53, 55, 56, 57, 59, 66

ELLINGHAUS FrankBANERJEE Vaishali

65

BARISH Kenneth N.

181

BAZILEVSKY Alexander

171

42, 44, 46, 47, 48, 50, 54,

149

BANERJEE Ajoy Sankar

255

176, 187, 191, 197

56, 57BENTZ Wolfgang

36, 37

12

180, 220

EMAM Waled S.

181

EMORI Shoken

江守昭憲

EMOTO Takashi

江本EN’YO Hideto

延與秀人

68

隆

77, 15378, 79, 80, 81, 199, 200, 203,
205, 207, 209, 211, 212, 214,46, 72

BEAUMEL Didier

66

出道仁彦

ASAI Junkichi

BAZIN Daniel

192

DEMICHI Kimihiko

旭

BAKULE Pavel

72

174

DESHPANDE Abhay

ASAHI Koichiro

馬場秀忠

174

CRISTIAN Cailan

青木孝道
有馬朗人

BABA Hidetada

174

CLARK Michael

青木和也

ARIMA Akito

184, 222

38, 39, 42, 44, 45, 46, 47, 49, 51,

青木慎也

AOKI Takamichi

186

CAMPBELL Chris M.
CHEN Dong

139

天野淳二

72

176, 183, 189, 190, 191,

秋葉康之

56, 57

214

224
ENDO Kazutoyo

遠藤和豊

123

i

ENDO Natsumi

榎本秀一

209, 212, 224

111, 112, 115, 116, 117,GROSSE-PERDEKAMP Matthias

118, 119, 120, 121, 122,

GUILHERME Amadio

123, 124, 125, 126, 127

HABA Hiromitsu

185

43, 7576, 109, 110, 111, 112, 113,

羽場宏光

184, 220

114, 115, 117, 118, 120,

48, 50, 53, 58, 66

121, 122, 124, 125, 127,

EYSER Kjeld Oleg
FÜLÖP Zsolt

39, 45, 49, 51, 52

遠藤奈津美

ENOMOTO Shuichi

FIELDS Douglas E.

182, 199, 201, 203, 212

FRASCARIA Nimet

56, 57

FUJII Kazuyuki

209

藤井和行

129, 130, 227, 229
HAEBERLI Willy

186

HÆGEMANN Christina

FUJIKAWA Hisashi

藤川尚志

43, 75

HAMAGAKI Hideki

FUJIMAKI Masaki

藤巻正樹

3, 5, 239

HAN Ran

FUJITA Shin

新

藤田

271

201, 220
192, 193, 194, 224

浜垣秀樹

220

HARA Mitsuo

原

227

光雄

FUJIWARA Hiroki

藤原裕樹

67

HARANO Hideki

原野英樹

82

FUJIWARA Kohei

藤原康平

199, 200, 203, 205, 207,

HASAMA Masako

挾間昌子

115, 116

209, 211, 214

HASEBE Hiroo

FUKAO Yoshinori

深尾祥紀

175, 187, 197, 198

HASEGAWA Hirokazu

長谷川浩一

46, 66

HASEYAMA Tomohito

長谷山智仁

68, 69, 70, 90, 145,

FUKUCHI Tomonori

61, 62, 74, 75, 150

福地知則

FUKUDA Hiroyuki

福田弘幸

254

FUKUDA Mitsunori

福田光順

67

251, 252, 254

長谷部裕雄

155, 156

FUKUDA Naoki

福田直樹

39, 45, 46, 49, 51, 52, 56,

FUKUI Toshiaki

福井利晃

61, 62, 63, 71, 146

HASHIMOTO Koichi

橋本耕一

169

HASHIMOTO Yoshiko

橋本佳子

38, 39, 45, 46, 49, 51,

57, 58, 65, 66, 259
FUKUNISHI Nobuhisa

福西暢尚

FUKUYAMA Yoshimitsu
FUKUZAWA Seiji

船木靖郎

29

橋本幸男

3, 5, 7, 86, 131, 134,

HASUKO Kazumi

136, 137, 138, 139,

HATAKEYAMA Atsushi

185

蓮子和巳

101, 103, 104

畠山 温

165

140, 141, 142, 241,

HATSUDA Tetsuo

245, 246, 248, 252,

HAYASHI Erina

林絵里菜

121

261, 263, 264

HAYASHI Reiko

林

玲子

138

HAYASHI Yoriko

林

依子

137, 140, 141, 142, 245

福山祥光

福澤聖児

FUNAKI Yasuro52, 53, 61, 62, 63, 71
HASHIMOTO Yukio

104

初田哲男

5, 7

HE Jianjun

17

HELLHAMMER Rolf

何43, 60, 64, 75

建軍

100

FURUKAWA Takeshi

古川 武103, 104

HEUSER Johann M.

207, 209FURUKAWA Yukihiro

古川幸弘

77, 153

HIEJIMA Hiroyoshi

比江嶋裕喜

176, 222

FURUSAWA Yoshiya

古澤佳也

132

HIGASHIYAMA Koji

東山幸司

25, 26FUTAKAMI Udai

二上宇内

GABBERT Dominik

185

GACSI Zoltan

HIGURASHI Yoshihide

3, 5, 7, 42, 47, 58,

日暮祥英

66, 229, 231, 233,

58

GADE Alexandra
GARA Alan58, 66263
HIRAKI Ko-ichi

HIRAYAMA Ryoichi

平山亮一

132

48, 50, 53, 55, 56, 57, 59

HIRUNUMA Rieko

蛭沼利江子

271

174

GIBELIN Julien
GILL Ronald

107

72

HISAYUKI Torii

186

開

康一

220

鳥井久行

GLASMACHER Thomas

72

HOBBS Robert

GOMI Tomoko

39, 42, 44, 45, 46, 47, 49, 51,

HOEFERKAMP Martin

52, 53, 56, 57, 58, 66

HOKOIWA Naho

鉾岩菜穂

60, 64, 74

60, 64, 75, 127

HONDA Chikako

本田智香子

123

五味朋子

GONO Yasuyuki
GOTO Akira

GOTO Shin-ichi
GOTO Yuji

ii

郷農靖之

後藤

彰

3, 5, 7, 229, 233, 235, 237, 246,

HONMA Masamitsu

248, 250, 251, 252, 261, 263,

HONMA Michio

264

HORAGUCHI Takuma

後藤真一

後藤雄二

182

76

176, 183, 197, 198, 199, 203,

HORI Fuminobu

201

本間正充

本間道雄

21, 22

洞口琢磨

堀 史説

HORIBATA Takatoshi

133
176

89

堀端孝俊

29

HORIGOME Atsuko

堀米敦子

271

ITOU Tatsuhiro

HORIUCHI Hisashi

堀内 昶

17, 18ITSUKI Yoshinori

HORVÁTH Ákos

48, 50HOSHINO Masamitsu

IWAI Yoshio

HOSOI Motooki

細井基興

HUANG Haixin

186

55, 59ICHIDA Hiroyuki

市田裕之

ICHIHARA Takashi

市原

ICHIKAWA Masahiro
ICHIKAWA Yuichi
IDEGUCHI Eiji
IEKI Kazuo
IGO George
IIDA KeiIWAO Yoshihiko

岩尾快彦

146

IWASA Naohito

岩佐直仁

42, 44, 47, 48, 50, 53, 54,

IWASAKI Hironori

38

54, 55, 58, 59, 60, 61, 62,
63, 64, 65, 66, 71, 72, 74

48, 50, 61, 62, 71, 74, 75,

IWASAKI Masahiko76

IWASE Akihiro

岩瀬彰宏

89

IZAWA Masaaki

伊澤正陽

266

IZUBUCHI Taku

出渕168, 16942, 47, 55, 59, 61, 62, 63, 66, 71
85

五十嵐明則

186

IZUMI Masako
13, 166

泉

卓131, 132雅子

IZUMIKAWA Takuji

五十里千尋

136

JAKOVÁC Antal

167

池田清美

14, 15JEGOU Guillaume41, 157

IKEDA Naomi

池田直美

87

JINNOUCHI Osamu

池田時浩

86, 95, 98, 100, 243

JOÓ Balint

IKEDO Yutaka

池戸 豊

149

JUNG Chulwoo
251, 252, 254

池上九三男

67

泉川卓司

IKEDA Kiyomi
IKEDA Tokihiro

82, 83, 149

岩崎雅彦

IKARI Chihiro

IKEGAMI Kumio

38, 42, 44, 47, 48, 50, 53,

岩崎弘典

38, 44, 48, 50, 65

井手口栄治

飯田 圭

133

岩木正哉

55, 58, 59, 61, 62, 66

146, 159, 220, 222, 224

市川雅浩

家城和夫

95

岩井良夫

IWAKI Masaya

91

齋宮芳紀

137
卓

市川雄一

IGARASHI Akinori

95, 96, 97, 98, 100

星野正光

103, 104

伊藤龍浩

186

陣内 修

174
174

KAGEYAMA Kensuke

蔭山健介

88
3, 5, 7

IKEZAWA Eiji

池沢英二

3, 5, 248, 255

KAGEYAMA Tadashi

影山

IMAI Nobuaki

今井伸明

42, 44, 46, 47, 53, 58, 63, 66,

KAJI Daiya

76, 109, 110, 113

71

KAJIHARA Fukutaro

梶原福太郎

189, 193, 194

IMAO Hiroshi

今尾浩士

82, 83

KAKUTANI Nobukazu

角谷暢一

257

INABE Naohito

3, 5, 7, 87, 248, 250

稲辺尚人
井上壮志

KALINKA Gábor

正

53

227

KAMATAKI Shinji

鎌滝真次

114

69, 70, 90, 91, 145, 154, 155,

KAMBARA Tadashi

神原41, 86, 88, 89, 97, 98,

INAMURA Takashi Thomas
INOUE Takeshi

加治大哉

稲村

卓

正

156
ISERI Yasunori

井芹康統

ISHIDA Carolina

74

100, 157

12

KAMEDA Daisuke

68, 69, 70, 73, 90, 91,

亀田大輔

128, 145, 155, 156

ISHIDA Katsuhiko

石田勝彦

82, 83, 149

KAMETANI Soichiro

亀谷聡一朗

ISHIDA Yoshihisa

石田佳久

41, 148, 157

KAMEZAWA Chihiro

亀澤智博

KAMIGAITO Osamu

上垣外修一

ISHIHARA Masayasu

39, 45, 46, 49, 51, 52,

石原正泰

220, 222, 224
87
3, 5, 7, 235, 237,

58, 66ISHII Nobuyoshi

石井伸昌

125

ISHII Noriyoshi

石井理修

171

ISHII Tetsuro

石井哲朗

ISHII Toshiaki

石井紀明

ISHIKAWA Katsutoshi

264

75
120
119

ISHIKAWA Kazuhiro

石川和宏

55, 56, 57, 59, 66

石塚成人

173

192

KAMIHARA Nobuyuki

神原信幸

188, 216

KAMIMURA Masayasu

上村正康

12

KAMISHIMA Junji

石川勝利

ISHIZUKA Naruhito
ISOBE Tadaaki

246, 250, 261, 263,

KANAI Yasuyuki

119

上島淳慈

KANADA-EN’YO Yoshiko

延與佳子

41, 86, 88, 95, 96, 97, 98,

金井保之

100, 157
KANAVETS Vadim P.

186

ITO Atsushi

伊藤 敦

132

KANAYA Kazuyuki

金谷和至

ITO Sachiko

伊藤祥子

77, 153

KANAYA Takeshi

磯部忠昭

ITO Yasuyuki

伊東靖之

138

ITOH Keisuke

伊藤圭介

38

ITOH Masatoshi

伊藤正俊

KANNO Shouko

173
140, 141

金谷健至

KANAYAMA Yousuke
KANESUE Takeshi

38

11, 16

金山洋介

金末 猛

菅野祥子

121, 122

105, 106, 268, 269

42, 47, 48, 50, 54, 61, 62,

iii

63, 66, 71, 72
KANO Hiroyuki

狩野博之

199, 200, 203, 205, 207, 209,

KANOH Hiroki

稼農広樹

216

小林-込山美咲

KOBAYASHI-KOMIYAMA Misaki

7,211, 214KANUNGO Rituparna
KASE Masayuki

239
KODAIRA Jiro48, 50KASAMATSU Yoshitaka

KOGO Miho
227

加瀬昌之

KATŌ Kiyoshi

13

3, 5, 7, 87, 93, 94, 229, 235,

KOHARA Shigeo

小原重夫

3, 5, 7, 235, 250

239, 241, 243, 245, 248, 250,

KOIDE Tomojirou

小出知次郎

15

片山一郎

KATO Go68

加藤 剛

41, 102, 157

82, 83加藤岑生

KOIKE Takeshi

134

74

小池武志

KOJIMA Takao M.

41, 88, 98, 157

小島隆夫

KOMAKI Ken-ichiro

KATAYAMA Ichiro
KATO Mineo

105

柏木啓次

加藤幾芳

209

向後美保

小濱洋央

251, 252, 254, 255
KASHIWAGI Hirotugu

163

小平治郎

KOHAMA Akihisa

笠松良崇

3, 5,

86, 95

小牧研一郎

KOMATSUBARA Tetsuro

小松原哲郎

KONDO Chikara

近藤

86

KONDO Yousuke

近藤洋介

力

74

39, 44, 45, 46, 48, 49, 50,

KATO Reizo

加藤礼三

107

51, 52, 53, 55, 56, 57, 61,

KATO Seigo

加藤静吾

60, 6462, 63, 66, 71, 151
38, 147

KONDRASHEV Sergei

KAWAGUCHI Takeo

川口武男

243

KORSHENINNIKOV Alexey A.

KAWAHARA Tomomi

河原朋美

38

KAWABATA Takahiro

KAWAI Shoko

川畑貴裕

39, 44, 45, 48, 49, 50, 51, 52,

河合祥子

KAWALL David Michael

KOSEKI Tadashi

105, 106, 268, 269

小関55, 59KOTAKA Yasuteru

196, 197

KOURA Hiroyuki

77, 153, 266

忠

KOSHIMIZU Masanori

53

越水正典

93, 945, 7

小高康照

30, 76

小浦寛之

KAWAMURA Hirokazu

川村広和

69, 70, 155, 156

KOYAMA Ryo

小山 亮

KAWAMURA Hiroyuki

川村浩之

163

KRAL Antonin

220

KAWAMURA Naritoshi

河村成肇

82, 83KREBS Gerry F.

67

KUBO Kenya M.

久保謙哉

128, 129

KUBO Toshiyuki

久保敏幸

41, 46, 56, 57, 58, 61, 62,

KAWASAKI Takeo

KHODINOV Alexander
KIBE Michiya

KIJIMA Go

186
60, 64

木部道也

KIDERA Masanori
KIENLE Paul

207, 209

川崎健夫

63, 65, 66, 71, 72, 74, 157,

3, 5, 7, 229, 233, 263

木寺正憲

34
68, 69, 70, 90, 91, 145, 155, 156

木島 剛

KIKUKAWA Yoshio
174

KIMURA Kazuie

木村一宇

KIMURA Masaaki

木村真明

KIMURA Shuichi

木村修一

久保木浩功

38, 147

KUBONO Shigeru

久保野

42, 43, 47, 54, 55, 59,

茂60, 64, 65, 66, 75, 231

109, 227

菊永英寿

KIM Changhoan

257, 259
KUBOKI Hironori

173

菊川芳夫

KIKUNAGA Hidetoshi

3

KUBOYAMA Satoshi

工藤久昭

76

93, 94KUDO Toshiaki

工藤俊章

137

18

KUMAGAI Keiko

115, 116

KUMASHIRO Shinichi

神代真一

KUNIBU Makoto

誠

119

87

久保山智司

KUDO Hisaaki

235

熊谷桂子

67

42, 47, 58, 66

KINUGAWA Nobuyuki

衣川信之

KISHIDA Takashi

隆

43, 73, 75

KITAJIMA Masashi

北島昌史

96

KURAMASHI Yoshinobu

KITAMOTO Yusuke

北本優介

111, 112, 113

KURATA-NISHIMURA Mizuki

倉田-西村美月

KURITA Kazuyoshi

53, 54, 55, 59, 61, 62,

岸田KITAYAMA Mitsuhisa

來山益久

KOBAYASHI Kei

啓小林39, 45, 49, 51, 52, 146

倉門雅彦
藏増嘉伸

栗田和好

151

小林清志

5, 7

KOBAYASHI Tohru

小林103, 104

徹

小林知洋

173
43

186
KUROKAWA Meiko

黒川明子

9, 16143, 53, 54, 55, 58, 59,
74, 150

KOBAYASHI Toshio

小林俊雄

39, 45, 46, 49, 51, 52

KUSAKA Kensuke

日下健祐

KOBAYASHI Yoshio

小林義男

70, 73, 91, 128, 129,KWEON MinJung

216

130, 155, 156

LAWLEY Sarah

iv

143

63, 66, 71, 72, 77, 153,

KOBAYASHI Kiyoshi
KOBAYASHI Tomohiro

國分

KURAKADO Masahiko

36

71, 257, 259

LEE Chun-Sik

李春植

60, 64

MIKI Kenjiro

LEE Ju-Hahn

李柱漢60, 64

MINAMISONO Tadanori

LEVKOVA Ludmila
LI Zheng

174

MINAYOSHI Ryuji

LIAO Xiaodong
LIMA Victor

67

南園忠則

119

皆吉龍二

MINEMURA Toshiyuki

186, 199, 212

147

三木謙二郎

42, 47, 54, 55, 58,

峯村俊行

59, 61, 62, 63, 66,

174

71, 151

56, 57

LIOUBIMOV Vladimir
LISKA Tomas220

LIU Guofeng

174

MITSUMOTO Toshinori

177, 178

LIU Zhong

58

MIURA Motooki
MIWA Koji
186

MACKAY Waldo W.

186

MADOKORO Hideki

間所秀樹

MAEDA Nobuhiro

MAETA Hiroshi

89

前田修大

67

前村

尚

前田裕司

209
251, 252, 254

真家武士

MAKDISI Yousef

149

牧村俊助

5, 7, 235

MATSUDA Yasuyuki
MATSUI Nobuyuki

82, 83, 149

松田恭幸

39, 45, 49, 51, 52, 146

松田洋平
松井信行

MATSUMIYA Ryohei

MIYAZAWA Yutaka

宮沢豊

MIYOSHI Hisanori

三好永哲

水崎壮一郎

130

水崎高浩

21, 22

百田佐多生

67

文

俊永

60, 64, 75

志郎

139
55, 59MORIKAWA Hitoshi

森川

MORIMOTO Kouji

森本幸司

74, 76, 92, 110

森下景子

114

MORISHITA Keiko
MORITA Kosuke

斉76, 110

森田浩介

MORREALÉ Astrid
MOTIZUKI Yuko

181, 22031, 32

望月優子

MOTOBAYASHI Tohru

本林 透

146

松本洋明

MATSUMOTO Ken-ichiro

森

134, 137
68, 128, 156

257

溝井 浩

59
67

141

潔

39, 45, 49, 51, 52, 53, 55,

松宮亮平

MATSUMOTO Hiroaki

128

淳

宮崎

MORI Shiro77, 153

増田鉄也

MATSUDA Yohei

宮崎

MOON Jun Young

95

益田邦和

MASUDA Tetsuya

35

丸山敏毅

益田秀樹

MASUDA Kunikazu

149
96

MOMOTA Sadao

MARUYAMA Toshiki
MASUDA Hideki

三宅康博

MIZUSAKI Takahiro

201

74

宮川一尚

宮本佑二

MIZUSAKI Soichiro

MAKIMURA Shunsuke
MALIK Michael46, 66MIYAKE Yasuhiro

MIZOI Yutaka

186

248

密本俊典

MIYAMOTO Yuji
MIYAZAKI Kiyoshi

112, 227

218

三輪浩司

MIYAZAKI Jun

38

前田幸重

MAEMURA Takashi

31, 32

三頭聰明三浦元隆

MIYAKAWA Kazutaka

LOZOWSKI William

MAEDA Yukie

192

MITSUGASHIRA Toshiaki

LIU Ming

MAIE Takeshi

MIODUSZEWSKI Saskia

41, 157

1, 39, 42, 43, 44, 45,
46, 47, 48, 49, 50,

123

松本謙一郎

51, 52, 53, 54, 55,

MATSUMOTO Takuma

松本琢磨

12

56, 57, 58, 59, 61,

MATSUMOTO Tetsuro

松本哲郎

82

62, 63, 65, 66, 71,

MATSUO Keiji

松尾啓司

111, 112, 113

MATSUO Ryo

松尾 亮

38

MATSUO Yukari

松尾由賀利103, 104

MATSUOKA Keisuke

松岡圭介

123

MATSUTA Kensaku

松多健策

67

72, 143, 151, 259
MOTOMURA Shinji

本村信治

MUELLER Wilhelm F.

72

MUKAI Hiroki
MURAI Koji

127

271

向井弘樹

136

村井耕二

松山裕一

42, 47, 66

MURAKAMI Hiroyuki

村上浩之

66

MATSUZAKI Teiichiro

松崎禎市郎

82, 83, 149

MURAKAMI Tetsuya

村上哲也

61, 62, 146

MAWHINNEY Robert D.

174

MURANAKA Konomi

村中九水

67

MATSUYAMA Yuuichi U.

MCCANN James F.

MIHARA Mototsugu
MIKES Petr

220

道正新一郎

三原基嗣

70, 155, 156

MURATA Jiro

村田次郎

42, 47, 54, 60,

MUTO Ryotaro

武藤亮太郎

61, 62, 64, 66,

MYO Takayuki

明 孝之

74, 75NAGAE Daisuke

85

MICHIMASA Shin’ichiro

長江大輔

67

78, 79, 80, 81

15
68, 69, 70, 73, 90, 91, 128,
145, 155, 156

NAGAMINE Kanetada

永嶺謙忠

82, 83, 149v

NAGASE Makoto

3, 5, 7, 248, 252, 255

長瀬 誠

NAGASHIMA Tadashi
NAGATA Yujiro

長島

長友 傑

NAKABAYASHI Takumi

野地俊平

147

NOJIRI Yoichi

野尻洋一

67

NONAKA Hiroshi

野中弘志

128

67

NORO Yoshihiko

野呂良彦

130

130

永田勇二郎

NAGATOMO Takashi

NOJI Shumpei138

正39, 45, 49, 51, 52,

中林 彩

NOTANI Masahiro

48, 50, 54, 55, 59, 60, 64,

野谷将広

61, 62, 63, 65, 71,151
NAKAGAWA Itaru

NAKAGAWA Takahide
NAKAI Yoichi

186

中川 格

中川孝秀

中島真平

NAKAMURA Masato

75

小田島仁司

103

OGATA Kazuyuki

261, 263

OGAWA Akio

OGIWARA Kiyoshi

185

荻原

清

小原麻里

138

77, 153, 254

OHIRA Hideharu
OHIRA Seiko

12

緒方一介

小川暁生

OHARA Mari

266

中村典雄

小田原厚子

67

中村仁音

NAKAMURA NorioODAHARA Atsuko
ODASHIMA Hitoshi

3, 5, 7, 229, 233,

41, 86, 88, 95, 96, 101, 157

中井陽一

NAKAJIMA Shinpei

66, 759, 161
87

大平秀春

107

大平聖子

82, 83

OHKI Tomonori

大木智則

NAKAMURA Takashi

中村貴志

41, 102, 157

OHKOSHI Kazuo

大越一雄

138

NAKAMURA Takashi

中村隆司

39, 42, 44, 45, 46, 47,

OHNISHI Hiroaki

大西宏明

84, 199, 200, 203, 205,

NAKAMURA Satoshi N.

中村 哲

3

49, 51, 52, 53, 55, 56,

207, 209, 211, 214

57, 59, 61, 62, 63, 65,

OHNISHI Jun-ichi

大西純一

233, 248, 251, 252, 255

66, 71, 72

OHNISHI Tetsuya

大西哲哉

48, 50, 53, 76, 146, 259

大西哲也

44, 74NAKAMURA Takeshi

仲村武志

5, 7

OHNISHI Tetsuya

NAKANISHI Takashi

中西 孝

227

OHSHIRO Yukimitsu

115

OHTA Ryuichi

太田隆一

5, 7

OHTA Shigemi

太田滋生

174

NAKANISHI Yukiko

中西由季子

NAKANO Kazuhiro

中野和城

254

5, 7, 231

大城幸光

NAKANO Kenichi

中野健一

183

OHTAKE Masao

NAKANO Masaru

中野

139

OHTANI Munehisa

大谷宗久

165

優

259

大竹政雄

NAKANO Yuji

中野祐司

86

OHTANI Shunsuke

大谷俊介

41, 102, 157

NAKAO Aiko

中尾愛子

161

OHTSUBO Takashi

大坪

67

NAKAO Taro

中尾太郎

NAKASHIMA Yoshiki
NAKASHITA Hideo

38, 44, 53, 65, 71

OHTSUKI Tsutomu

67

OHYAMA Takuya

中島良樹

137

仲下英雄

NAKAYAMA Akihiro

中山明弘

117

NAKAYAMA Koichi

中山光一

266

NARUKI Megumi

恵成木

NARUSAWA Tadashi

78, 79, 80, 81
98

成沢 忠

NASS Alexander

186

NEBIKI Takuya

根引拓也

NEMOTO Yukio

根本幸雄

NIIKURA Megumi

新倉

NIKOLSKII E. Yu.

53

NISHIDA Minoru

西田

NISHIKAWA Yasuyuki
NISHIMURA Hitoshi

98
171

OKADA Kensuke

岡田謙介

176, 191

OKADA Kunihiro

岡田邦宏

41, 102, 157

OKADA Takuya

130

岡田卓也

OKAMURA Hiroyuki

岡村弘之

38

OKAMURA Masahiro

岡村昌宏

105, 106, 268, 269

大川正典

173

5, 7

OKUNO Hiroki

奥野広樹

3, 5, 7, 251, 252, 254

ONG Hooi Jin

王39, 44, 45, 49, 51, 52, 54, 65,

奥村俊文

39, 45, 49, 51, 52, 53,
61, 62, 63, 65, 71

138

西川康之

60, 64

西尾和人

124

西尾和之

71
ONISHI Takeo K.

39, 44, 45, 49, 51, 52, 61,

大西健夫

62, 63, 65, 71
ONUKI Yoshiyuki

小貫良行

95

41, 157

野口基子

惠仁

118
43, 44, 60, 64, 75, 150

vi

186

稔

西村仁志

野田耕司

171

真

岡田裕美

OKUMURA Toshifumi

西村美月

NOGUCHI Motoko

岡OKADA Hiromi

OKAWA Masanori

西村俊二

NODA Koji

119

55, 59, 61, 62, 71, 74

NISHIMURA Mizuki

NISHIO Kazuyuki

227

大槻 勤
大山拓也

潤

NISHIMURA Shunji
NISHIO Kazuto

OKA Makoto

隆

209, 211, 214
ONUMA Ryoko

119

199, 200, 203, 205, 207,

小沼亮子

OSHIMA Nagayasu

137

大島永康

41, 157OSHIMA Sachiko

154

大島佐知子

SAKUMA Fuminori

佐久間史典

78, 79, 80, 81

SAKUMA Yasunobu

佐久間泰亘

123

OTA Masahiro

太田雅洋

67

OTA Shinsuke

大田晋輔

44, 53, 54, 55, 59, 61, 62, 63,

SAKURAGI Tomofumi

66, 71, 74, 75

SAKURAGI Yukinori

103, 104

SAKURAI Hiromu

OTA Yoshiho

太田嘉穂

OTOMO Hiromitsu
OTSU Hideaki

大友洋光

87

11

117, 118桜井 弘

SAKURAI Hiroyoshi

39, 42, 45, 46, 47, 48,

櫻井博儀

39, 45, 49, 51, 52

大津秀暁

120

桜木智史
櫻木千典

49, 50, 51, 52, 53, 54,

OTSUKA Takaharu

大塚孝治

21, 22, 23

55, 58, 59, 61, 62, 63,

OTSUKI Kazumasa

大槻一雅

96

65, 66, 71, 72, 146, 151,

OYAMA Hitoshi

95, 101

大山 等

259

OYAMADA Kazuyuki

小山田和幸

3

SASAKI Shoichi

OYAMATSU Kazuhiro

親松和浩

13

SASAKI Yuichirou

OZAKI Mizue

尾崎瑞枝

115

SASAMOTO Yoshiko

小沢48, 50, 67, 74, 76, 150

SASANO Masaki

OZAWA Kyoichiro
PERERA Aloy

193, 194小沢恭一郎

44, 53

SATO Hiromi

38

笹本良子

38

笹野匡紀

143

佐藤寛美

SATO Kiyokazu

243

佐々木雄一朗OZAWA Akira

顕

170

佐々木勝一

266

佐藤潔和

PETRECZKY Peter

167

SATO Nozomi

佐藤 望

76, 110

PETROV Konstantin

167

SATO Tadashi

佐藤雅志

137

PETROV Kostya

174

PURSCHKE Martin L.
RÖPKE Gerd
RAK Jan

192, 222

SATO Wataru

佐藤 渉

91, 111, 112

SATOH Yohei

佐藤洋平

87

SATOU Yoshiteru

1738, 39, 45, 49, 51, 52, 53,

佐藤義輝

56, 57182

RESCIA Sergio

186

SCHUCH Reinhold

ROSER Thomas

186

SCHUCK PeterRYKOV Vladimir L.

179, 199

RYUTO Hiromichi

龍頭啓充

SAHLMUELLER Baldo
SAIKA Daisuke
SAITO Akito

SCHUESSLER Hans A.

齋藤明登

41, 157

3, 5, 7, 93, 94, 131, 134,

SEELE Joseph

136, 137, 138, 139, 140,

SEIDL Ralf

141, 142, 151, 245, 248

SEIDL Ralf-Christian185

SEKIGUCHI Kimiko

関口仁子

SEKIMOTO Michiko

関本美智子

192
111, 112, 113

雑賀大輔

97

17
180, 198, 220

184

42, 46, 47, 53, 54, 55, 56, 57,

SERATA Masaki

58, 59, 66, 75

SHIBA Shigeki

41, 157

茂樹

SAITO Hajime

齋藤 肇

261, 264

SHIBATA Toshiaki A.

SAITO Hiroyuki

斉藤宏之

134, 136, 137, 139, 140,SHIMADA Hiroyuki

141, 142SHIMADA Kenzi

島田健司

SAITO Minoru

斉藤

135

SAITO Naohito

齊藤直人

186, 198SHIMADA Osamu

島田

修

87

SAITOH Hajime

斉藤 肇

233, 263

SHIMADA Sanae

嶋田早苗

136

稔

SAKAGUCHI Harutaka

209, 212

42, 47, 58, 66

世良田真来
柴

38

216

柴田利明

101

島田紘行

68, 69, 70, 73, 90, 91, 128,
145, 155, 156

146

坂口治隆

SHIMAMURA Isao

島村 勲

85

SAKAGUCHI Satoshi

坂口聡志

38

SHIMIZU Hirohiko

清水宏彦

143

SAKAGUCHI Takao

坂口貴男

192

SHIMIZU Hirotaka

清水洋孝

163

38, 147SHIMIZU Noritaka

清水則孝

23

SHIMIZU Tetsuya

清水鉄也

32

SHIMODA Tadashi

下田103, 104

SAKAI Hideyuki

酒井英行

SAKAI Hiroshi

坂井寛志

266

SAKAI Kazuo

酒井一夫

131

SAKAKIBARA Kazuhiko

榊原和彦

105, 106, 268, 269

SAKAMOTO Hisao

坂本久雄

271

SAKAMOTO Koichi

坂本浩一

136, 138

SAKAMOTO Naruhiko

坂本成彦

SHIMOMURA Koichiro
SHIMOURA Susumu

正

下村浩一郎
下浦

享

149

39, 42, 44, 45, 46, 47,
48, 49, 50, 51, 52, 54,

3, 5, 7, 38, 235, 237,

55, 58, 59, 61, 62, 63,

246, 250

66, 71, 74, 75

vii

SHINOHARA Atsushi

篠原

SHINOHARA Mayuko

厚

高橋和也

119

TAKAHASHI Masaki

高橋雅樹

124

38, 39, 45, 49, 51,

TAKAHASHI Naruto

高橋成人

111, 11252, 61, 62

TAKAHASHI Toshihiro

高橋利宏

107

TAKAHASHI Yoshiyuki

高橋良幸

38

67

篠島大亮

SHINTANI Eigo

新谷栄悟

173

SHIRAO Tsukasa

白尾

137

SHITSUKAWA Naoki

吏

136

漆川直希

53

SOSHI Takayuki

曽雌隆行

SPINKA Harold

186

高木宏之

266

TAKAMINE Aiko

高峰愛子

41, 157

TAKAMIYA Koichi

高宮幸一

TAKASE Kenichi

高瀬研以智

STINGELIN Lukas

237, 246
100

149

11

高柳俊暢

竹田浩之

竹久妃奈子

TAKEMURA Makoto

竹村

137
69, 70, 90, 91, 145,

真

155, 156

SUDA Shinichi

須田紳一

69, 70, 90, 91, 145, 155, 156

SUDA Toshimi

須田利美

74, 76, 77, 146, 153

SUEKI Keisuke

末木啓介

76

SUGAI Hiroyuki

須貝宏行

82, 83

TAKESHITA Eri

42, 47, 48, 50, 54, 55, 56,

竹下英里

57, 59, 61, 62, 63, 66, 71
TAKETANI Atsushi

199, 200, 203, 205, 207,

竹谷 篤

209, 211, 214, 216

119, 171

菅沼秀夫

SUGAWARA Kousuke

102

53, 146, 153

TAKEDA Hiroyuki
TAKEHISA Hinako

38

須田健嗣

SUGANUMA Hideo69, 70, 90, 91, 145, 155,

高階正彰

TAKAYANAGI Toshinobu

STOLTERFOHT Nikolaus

227
156

TAKASHINA Masaaki
220

STRASSER Patrick

TAKAKI Hiroyuki

126

STEPANOV Mikhail

SUDA Kenji

TAKAHASHI Kazuya

227
篠原摩有子

SHINOJIMA Daisuke

SOHLER Dóra91, 110, 111, 112, 113,

TAKEUCHI Satoshi

武内39, 42, 44, 45, 47, 48,

聡

55, 59菅原浩介

49, 50, 51, 52, 53, 54,

SUGIMOTO Satoru

杉本

聡

14

55, 56, 57, 58, 59, 61,

SUGIMOTO Takashi

杉本崇39, 45, 46, 49, 51, 52,

62, 63, 66, 71, 72

SUGIYAMA Masao

杉山正夫

SUGO Ryohei

TAKIZAWA Yoshiyuki
TAMAE Tadaaki

玉江忠明

77, 153TAMAKI Mitsuru

玉城 充

39, 44, 45, 49, 51, 52, 54,

61, 62, 63, 71

須合亮平

SUMIKAMA Toshiyuki

炭竃聡之

44, 53, 67

SUMIYOSHI Kohsuke

住吉光介

33

民井 淳

38

田辺孝哉

27

266

TANABE Shinzo

田辺信三

124

33

TANAKA Hideki

田中秀樹

67

44, 55, 59, 61, 62, 63, 65,

TANAKA Hiroshi

田中 大

96

71, 72, 151

TANAKA Kanenobu

田中鐘信

44, 61, 62, 63, 67, 71,

TANAKA Kazuhiro

田中和廣

163

TANAKA Manobu

田中真伸

199, 20938, 44, 53, 61, 62, 63, 65, 71

SUZUKI Hidenori

鈴木英範

SUZUKI Hideyuki

鈴木英之
宏SUZUKI Ken-ichi

鈴木賢一

SUZUKI Masaru K.

鈴木140, 141

鈴木美季子

SUZUKI Takao

鈴木栄男

SUZUKI Takeshi

鈴木

115

130
55, 59, 67

鈴木俊宏

124

鈴木吉光

SVIRIDA Dmitry N.

186

TAJIMA Naoya

孝博

30

197, 198

谷田 聖

TANIFUJI Makoto

谷藤 悃

40

TANIGUCHI Takashi

谷口貴士

130

TANIGUCHI Yusuke

谷口裕介

173

TANIHATA Isao

谷畑勇夫

48, 50, 55, 59, 67, 74

TASHIRO Yuki

田代祐基

111, 112, 113

TERAKAWA Teruhiko
TERANISHI Takashi

寺川輝彦
寺西

高

寺崎 順

20

125

田岸義宏

田嶋尚也

TAKABE Tomomasa

viii

橘

田上恵子

TAGISHI Yoshihiro

78, 79, 80, 81, 189

田原司睦

TACHIBANA Takahiro
TAGAMI Keiko

227

67

TABARU Tsuguchika151

TANIDA Kiyoshi

健

SUZUKI Yoshimitsu
SYMONS James44, 53, 61, 62, 63, 65, 71

賢

SUZUKI Mikiko

SUZUKI Toshihiro

61, 62, 63, 71, 74, 151
TANABE Kosai

鈴木大介

鈴木

滝沢義之

TAMII Atsushi

SUZUKI Daisuke

SUZUKI Hiroshi

143

55, 59, 66
142

59, 60, 64, 65, 75
40, 150

107

高部智正

142
42, 43, 47, 55, 56, 57,

TERASAKI Jun

TERASHIMA Satoru
109, 110, 111, 112, 113

TERRY James Russ

寺嶋 知

72

146

THOMAS Anthony W.
TOGANO Yasuhiro

36, 37WATANABE Shin-ichi
39, 44, 45, 48, 49, 50,

栂野泰宏

TOGAWA Manabu

外川

TOGAWA Tadayasu

兎川忠靖

TOHSAKI Akihiro
TOJO Junji

学

TOKAIRIN Hideo

東海林英夫
門叶冬樹

TOKI Hiroshi

土岐

WATANABE Shizui

渡辺静意

209

WATANABE Tamaki

渡邉 環

241, 243

176, 189, 193, 198

WATANABE Yasushi

渡邊 康146, 159, 220, 222, 224

124

WATANABE Yutaka X.
WETTIG Tilo

137

WINTER David76

WISE Thomas

冨田雅典

131, 132TORII Hiroyuki A.

鳥居寛之

95

TORII Hisayuki

TSUCHIMOTO Yuji
TSUKIORI Noritoshi
TURNER Jon

131, 132

塚田晃代

TSUKUI Masato

189, 195

本裕二

TSUKADA Teruyo

5, 7

月居憲俊

68

津久井正人

WOOD Jeﬀ

192
186

XIE Wei48, 50翠娥

189

YAHIRO Masanobu
YAKO Kentaro

12

八尋正信

38, 147

矢向謙太郎

YAKUSHIJI Takashi

薬師寺崇

46

YAMADA Kazunari

山田一成

42, 47, 55, 58, 59, 61,

201

62, 63, 65, 66, 67, 71,

UCHIDA Makoto

内田 誠

69, 70, 90, 145, 154, 155,
156

YAMADA Shoichi

UCHIDA Shigeo

内田滋夫

125

YAMADA Yasuhiro

UCHIYAMA Akito

内山暁仁

UE Koji

42, 47, 66

上41, 148, 157

186

WU Cuie

176, 179, 191

鳥井久行

186

WOLLNIK Hermann

TOMITA Masanori

浩二

UENO Hideki

上野秀樹

山上雅之

19

YAMAGUCHI Azusa

山口あづさ

174

山口

YAMAGUCHI Koji

山口考司

38

173

UMEBAYASHI Yukihiro

133

梅林志浩

UNDERWOOD David186

URITANI Akira

瓜谷章

UTSUNO Yutaka

宇都野 穣

82
21, 67271

上蓑義朋

VARENTSOV Victor

41, 157

VELYTSKY Alexander

167

38, 40, 150

YAMAGUCHI Takayuki

山口貴之

67, 76YAMAGUCHI Yoshitaka

山口由高

48, 50YAMAKA Shoichi

山家捷一

231

YAMAKI Tsutomu

八巻 務

271

27

WADA Michiharu

和田道治

山内 誠

92

山

170, 172山崎泰規

41, 102, 148, 157

若林泰生

43, 61, 62, 74, 75

YANAGA Makoto

3, 5, 7, 77, 153, 241

YANAGISAWA Yoshiyuki

涌井崇志碩

WANG Xiaorong

177

WATANABE Junko

矢永誠人

119

柳澤善行

38

39, 42, 44, 45, 46,
47, 48, 49, 50, 51,
52, 53, 54, 55, 56,
57, 58, 59, 60, 64,

122

鷲山幸信
渡邉

寛

渡辺功雄

WATANABE Kiwamu

41, 86, 88, 95, 96, 97,

77

WASHIYAMA Kohshin
WATANABE Hiroshi

34
98, 100, 101, 148, 157

若杉昌徳

王

剛

山崎敏光

WAKABAYASHI Yasuo
WAKUI Takashi

3

YAMAUCHI Makoto

WAKASUGI Masanori
WANG Shuo

135

山本義治

山内啓資

YAMAZAKI Takeshi
YAMAZAKI Yasunori

VOLYA Alexander

55, 59山口充孝

YAMAZAKI Toshimitsu

164

126

勇

YAMAMOTO Yoshiharu Y.

46, 56, 57

43, 65, 75

山口英斉

YAMAGUCHI Mitsutaka

YAMAUCHI Hiromoto

VINODKUMAR Attukalathil Mayyan
VOGELSANG Werner

YAMAGAMI Masayuki
YAMAGUCHI Hidetoshi

彰128, 129

山田康洋

YAMAGUCHI Isamu

上坂友洋

UWAMINO Yoshitomo

33

山田章一

145, 155, 156
UESAKA Tomohiro
宇川3251, 252

68, 69, 70, 73, 90, 91, 128,

UKAWA Akira

WATANABE Isao46, 58渡辺 裕

174

WHITTEN Charles

14, 15, 33

博

227

59, 61, 62, 63, 66, 71

199, 203, 212

TOKANAI Fuyuki

231, 235, 243

渡辺伸一

渡部 信

51, 52, 53, 55, 56, 57,

17

東崎昭弘

東城順治

WATANABE Shin68, 73, 75

130

渡辺順子
渡辺極之

66, 75, 151, 259
YANO Yasushige

矢野安重

3, 5, 7, 77, 127, 131, 153,
229, 233, 237, 241, 243,266
46245, 248, 250, 251, 252,
259, 263

ix

YASUDA Michiko

137

安田美智子

YASUI Hiroyuki

117, 118

安井裕之

YASUNO Takuma

安野琢磨

67

YATAGAI Fumio

谷田貝文夫

132, 133

YOKKAICHI Satoshi

78, 79, 80, 81, 219,

四日市 悟

220, 222, 224
YOKOTA Toshihiko

横田敏彦

161

YOKOUCHI Shigeru

横内

3, 5, 7, 248

YOKOYAMA Akihiko114, 227

横山明彦

YOKOYAMA Ichiro
YONEDA Akira

茂

239

横山一郎

3, 5, 7, 76, 88

米田 晃

YONEDA Ken-ichiro

46, 58, 65, 66, 72

米田健一郎

YOSHIÉ Tomoteru

吉江友照

173

YOSHIDA Atsushi

吉田41, 48, 50, 54, 66, 76,

YOSHIDA Koichi

吉田光一

YOSHIDA Shigeo

吉田茂男

敦

157, 159, 259
48, 50, 56, 57, 67, 74, 159,
259
YOSHIDA Tatsuhiko
YOSHIMI Akihiro

135

吉田辰彦

吉見彰洋

254

68, 69, 70, 73, 90, 91, 128,
145, 154, 155, 156

YOSHIMURA Takashi

吉村 崇

111, 112, 113

YOSHINAGA Naotaka

吉永尚孝

24, 25, 26, 35

92

YOSHINO Kenji

吉野賢二

YOUNUS Imran178, 182, 187, 220

YU Dantong

222

YUKAWA Noriko
YUKI Hideyuki

YUMOTO Atsushi

湯本

ZELENSKI Anatoli

186

ZENIHIRO Juzo
ZHAO Yumin

227
敦

銭廣十三

趙 玉民

ZIMMERMAN Aaron
ZWAHLEN Heather

x

271

湯川憲子
結城英行

24

201
72

124
146