UTTAC-75, 2006

UTTAC
ANNUAL REPORT 2005

TANDEM ACCELERATOR COMPLEX
Research Facility Center for Science and Technology
University of Tsukuba

http://www.tac.tsukuba.ac.jp/

UTTACANNUAL REPORT 2005
April 1, 2005 – March 31, 2006

UTTAC-75 2006

Executive Editors: Yasuo Nagashima
Editors: Yoshihiro Yamato, Kimikazu Sasa, Tetsuro Komatsubara

Cover photo: Cherry blossom in front of UTTAC.

UTTAC is a series of issues, which include annual reports of
Tandem Accelerator Complex, Research Facility Center
for Science and Technology, University of Tsukuba.
The issues may also include irregular reports written by English.
Copyright © 2006 by Tandem Accelerator Complex, Research Facility Center
for Science and Technology, University of Tsukuba and individual contributors.
All reports are written on authors’ responsibility and thus the editors are not liable
for the contents of the report.

Tandem Accelerator Complex, Research Facility Center for Science and Technology,
University of Tsukuba
Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577, Japan
http://www.tac.tsukuba.ac.jp/
annual@tac.tsukuba.ac.jp

PREFACE
During the academic year 2005, from April 2005 to March 2006, efforts have been paid to the stable
operation both of 12UD Pelletron and 1MV Tandetron as well as to the construction of new beam lines.
The new line for a μ-beam PIXE analysis has been constructed at the Tandetorn accelerator and a new
X-ray Si detector has been installed in the PIXE line. After finishing an acceptance test, the new line isgoing to throw into research works as a new service.
In the field of element analysis, the 36Cl accelerator mass spectrometry, 36Cl-AMS, has been
intensively used as a tool for studying of the A-bomb peak in the groundwater sampled at Germany. The
36

Cl-AMS made a contribution to assess the nuclear waste clearance level. A hydrogen analysis with p-p

elastic-recoil coincidence method has been applied to the geological research. The sensitivities andstabilities of both the AMS and the Hydrogen analysis have been improved and they are going to be
applied to the many research fields. The Eu concentration in Eu-doped GaN has been estimated by
Ruthford backscattering spectroscopy, RBS.
In the field of nuclear physics, the study of proton total cross section of p+12C and the search for the
resonant state in p+Si at the (p,n) threshold energy were precisely performed. A 118Sn(d,p) reaction was
intensively studied to look for deuteron Coulomb stripping.
In atomic and condensed matter physics, the evolution of resonant coherent excitation ofhydrogen-like ions has been observed with a 180° electron spectroscopy. Nano-scale and high aspect ratio
patterns were created on the SiO2 and TiO2 substances with accelerated fast heavy ions.
Without accelerated beams, Mössbauer studies on γ-Fe2O3 thin foils and a study of 3d transition-metaloxide system were pursued.
The agreement for the exchange of students has been established with the Department of Nuclear
Physics of the China Institute of Atomic Energy. According to this agreement, UTTAC is taking on a
Chinese graduate student for one year.
UTTAC organized one workshop and two symposiums. The workshop entitled “Mass measurementsin the isochronous rare-RI ring and nucleon-synthesis” has been held with 26 attendants and 12
contribution talks. The first East Asian AMS Symposium (EAAMS-1), and the 8th Japanese AMS
Symposium (JAMS-8), have been organized by the Tsukuba AMS group and successfully concluded. It
was attended by 120 peoples from 5 countries. The contributions to the symposiums, both technical andapplied, clearly demonstrated that AMS has evolved into a versatile tool to study our world, especially ourEast Asia, via long-lived radio-nuclides. The Proceedings of both Symposiums contain 44 papers coveringa large fraction of the contributions presented at the symposium

Yasuo Nagashima
Director-i-CONTENTS

1. ACCELERATOR AND EXPERIMENTAL FACILITIES
1.1

Accelerator operation 2005 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

1.2

Micro PIXE system for trace element analysis in single fluid inclusions of mineral samples

4

2. NUCLEAR PHYSICS
2.1

CDCC compound process and Oppenheimer Phillips effect . . . . . . . . . . . . . . . . .

7

2.2

Resonant state search in p+Si system around (p,n) threshold . . . . . . . . . . . . . . . . 10

2.3

118 Sn(d,p) reaction in search for Coulomb stripping of deuteron III . . . . . . . . . . . . .

2.4

Proton total cross section on 12 C near (p,n) threshold energy (2)2.5

Measurement of alignment correlation term in 20 F β decay . . . . . . . . . . . . . . . . . 16

2.6

Development of a high-efficiency method for α resonant scattering with the thick target

12. . . . . . . . . . . . . . 14

method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.7

Measurement of timing resolution for plastic scintillation counters in vacuum . . . . . . . 20

2.8

Particle identification using pulse shape analysis . . . . . . . . . . . . . . . . . . . . . . 22

3. ATOMIC AND SOLID STATE PHYSICS, AND CLUSTER SCIENCE
3.1

Evolution of resonant coherent excitation of hydrogen-like fast ions . . . . . . . . . . . . 25

3.2

Vicinage effect in the yield of convoy electrons under irradiation of fast carbon cluster ions 27

3.3

Möesbauer study on γ-Fe2 O3 thin films . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

3.4

The science of 3d transition-metal oxide system (2005-2006) . . . . . . . . . . . . . . . . 31

3.5

Oxidations of cobalt clusters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

3.6

Estimation of Eu concentration in Eu-doped GaN by RBS measurements . . . . . . . . . 34

4. ION BEAM ANALYSIS AND APPLICATION
4.1

Status of Tsukuba AMS system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.2

129 I-AMS by the Tsukuba AMS system

4.3

Test measurement of 36 Cl concentration in an ice core retrieved from the Dome Fuji

. . . . . . . . . . . . . . . . . . . . . . . . . . . 37

station in Antarctica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.4

Bomb-produced 36 Cl in the Oderbruch aquifer, Germany: A preliminary result . . . . . . 39

4.5

Improvements in sample preparation for 36 Cl-AMS . . . . . . . . . . . . . . . . . . . . . 40

4.6

Estimation of thermal neutron fluences in the concrete of verious accelerator facilities by
35 Cl AMS

4.7

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

Low Z element analysis of the Cr target deposited by HIVIPP method using a 1.8 MeV
He+ beam of Tandetoron accelerator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

4.8

Imaging of iodinated contrast medium using proton-induced quasi-monochromatic X-ray
emission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

4.9

Nanoscale and high aspect ratio patters on SiO2 and TiO2 created with fast heavy ions . . 49

4.10 New detection system of ERCS hydrogen analysis . . . . . . . . . . . . . . . . . . . . . 51

- iii -

5. TECHNICAL REPORT
5.1

New data aquisition system using CC/7700 . . . . . . . . . . . . . . . . . . . . . . . . . 55

6. RELATED TOPICS
6.1

Highly-concentrative immobilization of an enzyme only on a small sensitive area and its
effect on sensor preformance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

7. LIST OF PUBLICATIONS
7.1

Journals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

7.2

International conferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

8. THESES64

9. SEMINARS

64

10. SYMPOSIA

65

11. LIST OF PERSONEL

68- iv -

1.
ACCELERATOR AND EXPERIMENTAL FACILITIES1.1

Accelerator operation 2005

K. Sasa, S. Ishii, T. Takahashi, Y. Yamato, H. Kimura, H. Oshima, Y. Tajima, T. Komatsubara
and Y. Nagashima.
The 12UD Pelletron tandem accelerator
The total operating time and the experimental beam time were 2345.8 and 1963.1 hours, respectively.
The operating time was about 131.2 % relative to that in 2004. Fig.1 shows the accelerator operation hours
per month. The beam time histogram with respect to the terminal voltage is shown in Fig.2. Fig.3
represents percentage operation time of the three ion sources and ion species. Fig.4 shows the percentageof experimental beam time of the running research fields by the 12UD Pelletron tandem accelerator.
300

Machine Operation Hours

250
200
150
100
50
0

2005
Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

2006
Jan

Feb

Mar

Fig.1. Accelerator operation hours per month for the fiscal year 2005.

11 MV
10 MV

Terminal Voltage

9 MV
8 MV
7 MV
6 MV
5 MV
4 MV
3 MV
2 MV
0

100

200

300

400

500

600

700

800

Beam Hours

Fig.2. Beam time histogram as a function of the terminal voltage.

1

900

127Ｉ
AMS
0.1%
Ion Source 37Ｃｌ
35Cl
3.5%

129Ｉ
0.2%

0.3%
36Cl
7.1%

Polarized 3Ｈｅ
Ion Source 0.7%

1H
26.7%

2H
15.0%

SputterIon Source

197Au
4.2%

2H
21.6%

16O
16.8%

7Li
1.4%

12C
2.4%

Fig.3. Percentage operation hours of the three ion sources and ion species.

Developments(Instruments &Detectors)
4.5 %Accelerator Science
0.6 %Education
0.3 %Atomic and Solid
State Physics
14.3 %
Accelerator Mass
Spectrometry
11.2 %

Nuclear Physics(non-polarization)
44.8 %

Earth Science
3.1 %Applied Ion Beam
Science6.1 %Nuclear Physics(polarization)
15.1 %

Fig.4. Percentage experimental beam time of the research fields.
The 12UD Pelletron tandem accelerator had been operated at the terminal voltage lower than 10.5
MV by reason of the instability of the terminal voltage for the fiscal year 2005. The operation time atterminal voltage of 10 MV records the largest beam time. The accelerated time of Au ion increased in thefield of the material irradiation. In addition, 3He ion beam was used for the development of a thin solidstate detector.
The scheduled maintenance in the spring 2006 was started on March 2 and finished on May 8. All
corona points were replaced along the column and the accelerating tube. We also changed stripper foils of2the A and B foil units with new one. Especially, stripper foils with a diameter of 12 and 16 mm were set on
the B foil unit for AMS study. These diameters were larger than the normal foil diameter. A beam profile
monitor was set on the focal position for the accelerating tube in the accelerator tank. The beam profile
monitor will be used for adjusting the beam transport to the accelerating tube.
The 1MV Tandetron accelerator
The total operating time of the 1MV Tandetron accelerator was 348.7 hours for the fiscal year 2005.
This time was about 45.1 % relative to that in 2004. Fig. 5 shows the percentage of accelerated ions withthe 1MV Tandetron accelerator. Fig.6 shows the percentage of experimental beam time of the runningresearch fields. The main research field of the 1MV Tandetron accelerator was the cluster physics. The
1MV Tandetron accelerator was also used for trace-element analysis with particle induced X-ray emission(PIXE), Rutherford backscattering spectroscopy (RBS) and the education in the field of ion beam study.
Accelerated ions (1MV Tandetron)
H 12.0 %He 12.4 %C 4.8 %

C cluster
70.8 %

Fig.5. Percentage of accelerated ions with the 1MV Tandetron accelerator.

Developments(Instruments
and Detectors)
1.7 %Education
5.2 %RBS･ERDA
16.0 %PIXE
4.0 %Cluster physics
73.1 %

Fig.6. Percentage of experimental beam time of the running research fields
with the 1MV Tandetron accelerator.

3

1.2

Micro PIXE system for trace element analysis in single fluid inclusionsof mineral samples.

K. Sasa, S. Ishii, Y. Yamato and M. Kurosawa
A proton microprobe system has been developed at the 30° beam line (A−course) on the 1 MV
Tandetron accelerator. This system was designed to investigate the PIXE analysis in single fluid inclusionsof mineral samples. Fig.1 shows a schematic layout of the micro PIXE system. It consists of a beam
defining slit (first slit), a collimating slit (second slit), a steering magnet, a quadrupole doublet lens(ISM-10DQ-05, IDX Inc.), a new Si detector (Sirius series, 50 mm2 det. area, e2v scientific instruments
Ltd.) and a sample chamber. The sample chamber was already reported by Ref. [1] in detail. The
employed microscope (Wild M420 photomacroscope, Leica Ltd.) has a 102 mm working distance and 6
magnifications. The sample image can be observed on a monitor using a CCD camera and enlarged themagnification up to 360 by this unit. The angle of observation was 180° with respect to the incident beamusing a 45° mirror with a beam through hole. The sample stage can be moved to 90 mm and 25 mm along
the horizontal and vertical axes with a minimum step of 1 μm respectively. The quadrupole doublet lens
was designed to form a microfocused beam. The performance of the quadrupole doublet lens is alsopresented in Fig.1. The incident beam angle is normal to the sample surface. The Si detector is located at
135° relative to the beam direction and has a normal resolution of 143 eV at 5.9 keV. The length of thebeam line is limited within 3.5 m by the target room. The working distance is 300 mm. The beam
demagnification factors are calculated to 11.2 and 3.1 in the horizontal and vertical directions respectively.

Quadrupole doublet lens [IDX Inc.]
Bore radius: 5 mm
Pole length: 50 mm
Effective length: 55 mm
Pole gap: 70 mm
Max. field: 15.2 kG/cm (10 A)
SwitchingmagnetFirst slit

F.C.
& Viewer

Si detector
300
Steering
magnet

TMP

Quadrupole
doublet lens

Microscopewith CCD

Samplechamber

Second slit

3,500

Fig.1 Schematic layout of the micro PIXE system on the 1 MV Tandetron accelerator.
4

The size of a beam spot on the sample is important for investigations of the micro PIXE analysis insingle fluid inclusions. A preliminary test was performed with a 1.82 MeV proton beam. We observed
scintillation light emitted from a ZnS plate attached to the sample stage by irradiating the focused protonbeam. The beam spot size of 20 μm was obtained with a beam current of 1 nA. The minimum beam spot
size of less than 10 μm was achieved with a beam current of 0.1 nA by adjusting the width of the first slit.
Fig. 2 shows a photograph of the focused proton beam spot on the ZnS plate.

Fig. 2

A focused beam spot of the 1.82 MeV proton beam on the ZnS plate. The beam current is 0.1 nA.

The minimum scale on a ruler is estimated to 12 μm.
References[1] M. Kurosawa et al., Nucl. Instr. and Meth. B142 (1998) 599.

5

2.
NUCLEAR PHYSICS

2.1

CDCC compound process and Oppenheimer Phillips effect

Y. Aoki, M. Iijima, T. Ishikawa, and N. Okumura1
In 1935 Lawrence et al.,[1] reported energy dependence of (d,p) reactions on Na, Al, Si and Cu nuclei
below Ed = 3.6 MeV. They irradiated stacked targets by their ‘magnetic resonance accelerator’ , whoselaboratory slang was ‘cyclotron’ , and measured the residual activities. They noticed, contrary to theenergy dependence of proton and α particles induced reaction cross sections, that of (d,p) reaction was
weaker than the prediction of Gamow theory.
Oppenheimer and Phillips [2] solved this puzzle as follows. They wrote the initial wave function as
ψi = u(x, X) φ (X),
where u(x, X) is the wave function for the relative coordinate x, when the center of mass X is fixed, andφ (X) is the wave function for the center of mass. They separated the u(x, X) and φ (X),© 2ªh̄ /M ∆x + E (X) −V0 (x) −VN (x, X) u = 0
and

© 2
ª
h̄ /4 M ∆X +W − I − E (X) φ = 0.

In this expression V0 is the potential between neutron and proton, and VN is the nuclear potential. W
and I are total and deuteron binding energies. They took VN the Coulomb repulsion of the proton in
the deuteron and target, and neglected the specifically nuclear forces, i.e., ‘deuteron’ internal motion is
distorted by Coulomb potential. They evaluated u(x, X) at x = 2X by using WKB approximation. x = 2X
means rn = 0 and the neutron is located in the target nucleus. Their energy dependence of (d,p) reaction
is presented as Fig. 2-5 of ref. [1].
Coulomb distortion should introduce negative parity component into the ‘deuteron’ internal wave
function. N. Austern [3] studied this Coulomb polarization effect of the deuteron by using three bodymodel and evaluated the cross section ratio of σ (d,p)/σ (d,n). He approximatedT (d, p) = T (0) (d, p) + T (1) (d, p),
where
(−)

T (0) =< χ p (k p , r p )ψn (rn )|V (r)|ψd (r) F0 (R) >is the usual DWBA amplitude and T (1) stands for the deuteron breakup effect. He expected the (d,p) crosssection,σ (d,p), is enhanced than that of (d,n) reaction if Coulomb polarization is really meaningful. He
concluded the enhancement is less than 5 % and the Oppenheimer-Phillips effect is hidden by the Coulomb
effect under the proton bound state wave functions.
As is seen in the above expression, (d,p) reaction matrix element include V (r)ψn (rn ), the product ofshort range p-n interaction and neutron bound state wave function. This expression is not the one that
1 Nagano National College of Technology

7

Oppenheimer and Phillips suggested. We used the different approach from the Oppenheimer and Phillips
effect.
Let us write CDCC wave function as,
ΨM (R, r) = ∑ G(L0 J M) ∑ ΨcJ M (R, r)
c

J L0

where
ΨcJ M (R, r) =1
[iL YL (R̂) φIcc (r)]J M ΦcLJL0 (R)R∑L

have definite angular momentum and the expansion coefficient is given asp
4 π (2 L0 + 1) ei σL0
G(L0 J M) =(L0 0 I0 M |J M).
K0
Vectors R and r define center of mass and relative coordinates of the ‘deuteron’ . Wave function for the
CM motion Φ(R) satisfies the following equation,
µ 2
¶
0
h̄2
d
L(L + 1)−−ΦcLJL0 + ∑ Vc c0 ΦcLc0 JL0 = Ec ΦcLJL0 ,22
2µR dRR
c0 L 0and00

Vc c0 =< [iL YL (R̂) φIcc (r)]J M |V | [iL YL0 (R̂) φIcc0 (r)]J M >are matrix elements of sum of proton and neutron optical potentials, V = Vp (r) +Vn (rn ), sandwiched by‘deuteron’ internal wave functions. Φ(R)’s satisfy the usual incoming wave boundary condition, fromwhich following relation is derived for S matrix elements of break up channels, c.
Z
n
o
4 µR
cJ ∗
c0 J
cJ
∗
c0 J ∗
0
dR
Φ
V
Φ
−
Φ
V
Φ
|SLc JL0 |2 =
0
0
0
c
c
∑
L L0
L L0 c c L L0
L L0
i K0 h̄2 c0 L0This expression tells how the outgoing wave in channel c is generated. Included among the sums on c0 , wenotice the absorption effect from diagonal element, < c|ℑ {Vcc } |c >. We can identify that the reductionof |SLc JL0 |2 from neutron imaginary potential as the neutron absorption probability after incident deuteronis dissociated. It should be noticed that the matrix element Vcc has very long range.
Numerical calculation of CDCC compound process is made for 118 Sn(d,p) reaction. ‘Deuteron’ internal states of 3 S1 − 3 D1 , 3 D2, 3 , 3 P0, 1 , 3 P2 − 3 F2 are taken into account. Except for the 3 D3 state, Reid [4]soft core potential are used. Energetically open “break-up” channels are taken into account and discretized
as six separate wave number bins. Global nucleon optical potential of CH89 [5] was used. Three cases of
deuteron break up is considered, 1) pure Coulomb break up, 2) pure nuclear break up, and 3) both nuclear
and Coulomb interactions are responsible for the deuteron break up. In case 1), nucleon optical potential
is completely neglected.
Figures below shows the absorption cross section for each momentum bin. Plotted in the figure is thefollowing quantity,
“

4π
0
∆k ∑
3 ∑ ∑
c (2I0 + 1) K0 J L0 L cµZdR |ΦcLJL0 |2 Im¶
2 µR nWc c ,
h̄2

where ∆k is the wave number bin width of the p-n relative motion and the sum on c runs over same‘deuteron’ energy.

81.0e+02

1.0e+01

1.0e+01

1.0e+00
1.0e-01

1.0e-01

Ed=8 MeV
Ed=6 MeV

1.0e-02

Ed=5 MeV

118

1.0e-03Sn+d

1.0e-03

Ed=4 MeV

1.0e-05

Ed=4 MeV

1.0e-05pure Coul. BU

Sn+dpure Nucl. BU
Ed=3 MeV

1.0e-07

Ed=3 MeV

118

neutron absorption

1.0e-06

1.0e-06

Ed=10 MeV

Ed=6 MeV
Ed=5 MeV

1.0e-04

neutron absorption

1.0e-04

Ed=8 MeV

1.0e-02

Ed=10 MeV

abs. Xsec. (au)abs. Xsec. (au)1.0e+00

1.0e-08
0

1

2

3

4
E"d" (MeV)

5

6

7

8

0

1

2

3

4
E"d" (MeV)

5

6

7

8

1.0e+01abs. Xsec. (au)1.0e+00

Ed=10 MeV

1.0e-01

Ed=8 MeV
Ed=6 MeV
118

1.0e-02

Sn+d

Ed=5 MeV

neutron absorption
Nuc. + Coul. BU

Ed=4 MeV

1.0e-03

Ed=3 MeV
1.0e-04
0

1

2

3

4
E"d" (MeV)

5

6

7

8

Fig. 1. Energy dependence of neutron absorption. Abscissa is the ‘deuteron’ energy, while ordinate is theabsorption cross section. Upper left panel shows the case for pure Coulomb break up, upper rightpanel for pure nuclear break up and the lower panel for the case including nuclear and Coulomb
break up.

‘Deuteron’ energy of the rightmost point of each curve is lower from the incident energy by about 2.2
MeV, the deuteron binding energy.
Coulomb break up dominates for the lower energy case.
As was predicted by Oppenheimer and Phillips, energy dependence of (d,p) cross section is moderated
by including Coulomb break up process.

References[1] E. O. Lawrence, E. McMillan and R. L. Thornton, Phys. Rev. 48493(1935)[2] J. R. Oppenheimer and M. Phillips, Phys. Rev.48500(1935)[3] N. Austern, Phys. Rev.C43771(1991)[4] R. V. Reid, Jr, Ann. Phys50411(1968)[5] R. L. Warner, Phys. Rep. 20159(1991)

9

2.2

Resonant state search in p+Si system around (p,n) threshold

Y. Aoki, M. Iijima, T. Ishikawa, N. Okumura1 , and Y. Tagishi2
We reported the (p,n) threshold effect of total reaction cross section in p+Si system [1]. To confirm thiseffect in proton elastic scattering, new experiment was designed. It consists of measuring elastic scatteringcross section at backward angles with relatively thick target and a magnetic spectrograph. Protons incident
on the thick target will lose some kinetic energy before it is elastically scattered by the target nucleus.
Energy and relative intensity of the elastically scattered protons are dependent on what depth they arescattered. Elastically scattered protons will lose their kinetic energy before they really leave the target.
This energy loss after elastic scattering favors to improve the energy resolution of the resonance effect.
Following is a numerical example. Protons of 15.9 MeV are allowed to hit Si target of 100 µm thick,which is located perpendicular to the beam direction. Energy range of the elastic scattering is thus limited
from 15.33 to 15.90 MeV. Energy range of protons elastically scattered to 135◦ is expanded to 12.61 to
14.05 MeV. Energy range is thus amplified by about a factor of 2.5.
Feasibility test experiment was made successfully. Natural Si of 50, 100 and 150 µm targets are hit
by protons of E p = 15 to 16.2 MeV. Elastically scattered protons are momentum analyzed by an Engetype magnetic spectrograph (ESP90) and detected by using a single wire position sensitive proportionalcounter. Position information is extracted by a charge ratio method. Linearity of the focal position andthe momentum is confirmed by using elastic scattering of protons from thin gold target. Quadratic term isfound to be negligible small.
Sample momentum spectrum is given in fig. 1, where three proton spectrum of different target thickness are superposed. Elastic scattering builds up from about 830 ch. 50 µm spectrum spans about 600 to
830 ch, those of 100 and 150 µm about 400 to 830 channels. Energy dependence of elastic scattering has
many dips and valleys. Inelastically scattered protons span from 380 to lower channels. Triangular peakin 100 µm data around 370 channel is due to the fall of elastic and building up of inelastic yields.
Linear portion of the high energy edge, which correspond to elastic and inelastic scattering at the front
surface of the target, are used to calibrate the proton energy and are indicated by two vertical lines. Centerof mass energy of these lines correspond to 14.41 and 15.35 MeV, i.e., 800 keV energy range of CM
system is mapped onto 400 channels.
1) Definite change of elastic cross section near (p,n) threshold ( at around 700-725 channel) cannot
be seen.

2) Resonance states of less than 100 keV widths can easily be identified by this thick target

method.

References[1] N. Okumura, Y. Aoki, T. Joh, K. Hirota and K.S. Itoh, Nucl. Inst. Meth.A487565(2002)

1 Nagano National College of Technology
2 RIKEN104000
Ep=15.9 MeV

3500
3000

counts/ch

2500
2000
1500
1000

Ecm=14.41 MeV

Ecm=15.35 MeV

500
0
400

500

600

700

800

ch

Fig. 1. Proton momentum spectrum elastically scattered from 50, 100 and 150 µm thick target. Incident energy is 15.9 MeV and scattering angle is 145◦ . Target is placed 45◦ to the incident beam
direction. For more details, see the text.

11

2.3

118 Sn(d,p) reaction in search for Coulomb stripping of deuteron. III

M.Iijima, Y.Aoki, Y.Ito, T.Ishikawa, S.Igarashi and Y.Tagishi
Coulomb break-up of deuterons was proposed in 1930s[1] and a CDCC calculation suggested its
enhancement below Coulomb barrier with targets of large atomic numbers [2].
From December 2005 to February 2006 we measured differential cross section (σ (θ )) of 118 Sn(d, p0 )reaction at Elab = 5.5 ∼ 8MeV. The experiments were performed using 12 UD Pelletron at UTTAC.
Targets were 118 Sn with enrichment of 98.70 % and thickness around 500 ∼ 800µg/cm2 . Momenta of
deuterons and protons were analyzed by magnetic spectrograph ESP90. We used Single Wired Proportional Chamber of 30cm long as a focal plane detector. Solid angle was approximately 3.3 msr. Beamcurrent on target was around 100nA.
Fig.1 is a typical spectrum of protons taken by the SWPC, whereas deuterons were stopped by a
200µm absorber in front of it. The shaded area consists presumably of three peaks, which are from118 Sn(d, p) reactions leading to the ground state, the first and the second excited states of 119 Sn.

Fig.2

shows the sum of differential cross sections leading to these three unresolved states. A further analysis is
now in progress.

Fig. 1. A typical spectrum of protons

12

1.2

8 MeV
1

σ (mb/sr)

0.8

7 MeV

0.6

0.4

6 MeV
0.2

5.5 MeV
0
40

60

80

100

θCM (deg.)

120

140

160

Fig. 2. Sum of the experimental differential cross sections of 118 Sn(d, p0 ),118 Sn(d, p1 ) and 118 Sn(d, p2 )reactions

References[1] J.R.Oppenheimer and M.Phillips, Phys. Rev. 48,500(1935)[2] Y.Aoki, N.Okumura, H.Ishiguro, UTTAC ANNUAL REPORT, 22(2002)

13

2.4

Proton total cross section on 12 C near (p,n) threshold energy (2)T.Ishikawa, M.Iijima, Y.Ito and Y.Aoki
A resonance like behavior was predicted in nucleon-nucleus effective potential [1] at nucleon transfer
reaction threshold energy. A dip in the energy dependence of total reaction cross section σR near (p,n)
threshold energy was reported in 28 Si+p system [2] to be presumed as the behavior. In order to investigate
this threshold effect, another system of 12 C+p reaction was studied. Details of our confirming experimentare given in [2] and [3].
In our previous report [4], the dip in the σR for the 12 C+p system was not clearly observed becauseof the large experimental error which was 10 % as a relative error. In order to reduce the error of themeasurement two improvements were performed.
For the first improvement, a beam diffuser of 7µm thick tantalum foil was located at upstream ofthe switching magnet, as shown in Fig.1. Beam is strongly focused and tightly limited at the image slit
(horizontal width of 0.1mm) of the analyzing magnet. Therefore, tiny drift of accelerating voltage or amagnet field of upstream device may strongly affect beam path and intensity in the downstream. The
Diffuser broadens beam width in real and momentum space, and reduces the sensitivities by the upper
beam properties.
In our timing logic of the counting system is studied. The second improvement is I0 counter thatis a pair of proportional counters, spontaneous discharges occur by some reasons. Pulse height of thedischarge is sometimes larger than the true proton pulse. Spurious counts appeared in the higher energy
portion of the proton spectrum. So we use discriminator in window mode, and inspected the discharge
contribution. But this idea did not contribute to decrease the relative error. Using envelope mode of digital
oscilloscope, we checked and modified timing of other signals.
In 2005, we have experiments on June and July. The data of this year, together with the past ones, arepresented in Fig.2. June data has the smallest error in our experiments, but the expected dip can not be
seen. We used thinner target in July than in June (8.0 mg/cm2 ). Horizontal error of July data is not shown
because we do not have the data of precise thickness. About July data, the measured error is larger thanthat of June data and magnitude of the σR is getting small in low energy region. Origin of this decline inenergy dependence is not understood yet.

References[1] N.K.Glendenning, Direct Nuclear Reactions(1983), Academic Press[2] N.Okumura et al., Nucl. Inst. Meth. A487, 565(2002)[3] T.J.Gooding et al., Nucl. Phys. 12, 241(1959)[4] T.Ishikawa, Annual Report, University of Tsukuba, 2004
[5] M.Q.Makino et al., Nucl. Phys. 68, 378(1965)

14

Beam Duct

Beam Axis

for foil mounting

Fig. 1. Cross-sectional view of beam diffuser

800
700
600

σR[mb]

500
400
300
200
100
0
17.6

17.7

17.8

17.9

18

18.1

18.2

18.3

18.4

18.5

18.6

Energy[MeV]Feb-05

Jun-05Jul-05Makino et al.

Fig. 2. Energy dependence of σR in 12 C+p system (Qcm(p,n) =-18.12MeV). Abscissa is the c.m. Energy.
Black squares are the data of Makino et al.[5].

15

2.5

Measurement of alignment correlation term in 20 F β decay

T.Nagatomo, A.Ozawa, Y.Tagishi1 , K.Matsuta2 , M.Mihara2 , R.Matsumiya2 , M.Yamaguchi1 , T.Sumikama1 ,H.Ohta, T.Yasuno, Y.Hashizume, K.Minamisono3 , M.Fukuda2 and T.Minamisono4
The alignment correlation term in β -ray angular distribution is one of the good probes for the G-parity
violating weak nucleon currents and the meson exchange effects inside the nucleus. The G transformation
is defined as G ≡ CeiπTy , where C is the charge-conjugation operator and eiπTy is the charge-symmetry
operator. For on-shell nucleons with initial and final momenta pi and p f , respectively, the weak nuclear
axial vector current including the recoil effects, which are the operators composed of the γ matrices andqµ = p f − pi , is described as­¯¡¢
p f ¯ Aµ |pi i = iu(p f )γ5 fA γµ + fT σµν qν + i fP qµ u(p f )(1)

where u(p) is the proton or neutron wave function, fA , fT and fP are the main, induced tensor and pseudoscalar term, respectively. Under the G transformation, the induced tensor term fT has the opposite sign
against the fA and fP terms, thus it causes the G-symmetry breaking. The angular distribution of theβ -rays emitted from the purely aligned unstable nuclei is described as
2

W (θ , E, A ) ∝ 1 + α(E)A 3 cos2θ −1(2)where θ is the β -ray emitting angle respect to the quantum axes, E is the total energy of the β ray, A is
the nuclear alignment and α(E) is the alignment correlation coefficient. With the impulse approximationof the Hamiltonian density of the interaction of the nucleon current (Eq.1) with the lepton current, we
can obtain the fT from the difference between the linear term of the alignment coefficients α (1) of mirror
nuclei 20 F and 20 Na in the mass number A = 20 system as
Ã
!)
(
r
b
d
j
∆E
2
3
II
2
0
−
+
E
α (1) (20 F; E) − α (1) (20 Na; E) = −3M Ac Ac
14 Ac 2MA

(3)

where M is the nucleon mass, A is the mass number, ∆E0 is the difference between the end-point energyfgof 20 F and 20 Na, b is the weak magnetism and dII ∼= II = 2M T . In the present work, we have measured
Ac

Ac

gA

fA

the alignment correlation term of 20 F (I π = 2+ , T1/2 = 11s) by observing β -rays emitted from the purely
spin aligned nuclei by means of the β -NMR technique.
Experiment was performed at the University of Tsukuba Tandem Accelerator Complex (UTTAC).
The 6 MeV polarized deuteron beam was employed to produced the polarized 20 F nuclei through the→− −→polarization transfer 19 F( d ,p)20 F reaction by bombarding MgF2 single crystal plate. The typical beam
current and beam polarization were 1 nA and ∼ 80%, respectively. The details of experimental procedures
were shown in the previous work[1]. In the present work, the averaged polarization of 20 F was ∼ 8%with the asymmetry parameter of −1/3, and the β -ray counting rate was typically 20kcps. Utilizing
the combination of the depolarization (DEP) and the adiabatic fast passage method (AFP) on the four
1 RIKEN, Wako, Saitama 351-0106
2 Department of Physics, Osaka Univ., Toyonaka, Osaka 560-0043 Japan
3 NSCL, Michigan State Univ., East Lansing, MI 48824-1321, USA
4 Fukui Univ. of Technology, Fukui 910-8505 Japan16

resonance frequencies, which was split by the hyperfine interaction with the electric field gradient in
the MgF2 crystal. We could manipulate the spin ensemble and produce both the positive and negativealignment, A+ and A− . Comparing the intensities of β -rays emitted from the state of A+ and A− , thealignment correlation term was obtained.
We have to eliminate the background β rays from 25 Al (T1/2 = 7.2s, QE.C. = 4.3MeV) and 27 Mg(T1/2 = 9.5m, Qβ − = 2.6MeV) that were produced through 24 Mg (d,n) and 26 Mg (d,p) reactions, respectively. Typical β -ray time spectrum was obtained as shown in Fig.1. The ratio of the production rate
25

Al)
(P.R.) of 25 Al to that of 20 F was obtained as P.R.(= 0.165(4). Typical energy spectrum was observed
P.R.(20 F)

as shown in Fig.2. The β -ray-counter efficiency depends on the finite solid angle of the detector, and isaffected by the β -ray scatterings and the magnetic fields of 0.25 Tesla. For reliable analysis, these effects
are estimated for each energy with the Monte Calro simulation code EGS4[2], and are considered in thefitting function for the energy spectrum. As shown in Fig.2, such a theoretical spectrum with the background components fixed to the obtained production rate, fits to the experimental data very well, to showthat the background estimation is reliable within a few percent error for each energy. The alignment correlation term α(E) was obtained as shown in Fig.3. In the figure, the β -γ angular correlation term [3, 4],which is multiplied by −2/3 to compare with the obtained α(E), and the theoretical prediction calculatedwith the impulse approximation including higher order term such as j2 and j3 [5] are also shown. To givethe constraint of the existence of the fT / fA , the analyses on 20 Na as well as on 20 F are now in progress.
1

4.5

Sum

3

27Mg

2.5

0

25
20F

20

α(E) (%)

3.5

20F

β-ray counts (x104)

4log(U+D)

Exp.
25Al

15

25Al
27Mg

0

50 100 150 200 250 300
Time (s)Fig. 1. Typical β raytime spectrum.

-2

10
5

2

-1

Present work (uncorrected)
R.E. Tribble et al. [3]R.D. Rosa et al. [4]Theoretical (I.A.) [5]

-3

-4

3
4
5
2
1
Observed β-ray energy (MeV)

Fig. 2. Typical β ray energy spectrum.

0

1

2

3

4

[1] K.Matsuta et al., UTTAC Annual Report, 73, 14(2005), Genshikaku Kenkyu 49, (2005) 31.
[2] H.Hirayama et al., ”Lecture Notes of EGS4 Cource at KEK”, KEK Internal, 99-5, (1999)[4] R.D.Rosa et al., Phys. Rev., C37, 2722(1988).
[5] F.P.Calaprice et al., Phys. Rev.,C15, 2187(1977).

17

6

Fig. 3. uncorrected α(E) of 20 Fwith the β -γ correlation term
multiplied by −2/3.

References[3] R.E. Tribble and D.P.May, Phys. Rev., C18, 2704(1978).

5

Total Beta Energy (ΜeV)

2.6

Development of a high-efficiency method for α resonant scatteringwith the thick target method

H. Fujikawa1 , S. Kubono1 , A. Saito1 , H. Yamaguchi1 , G. Amadio1 , J. J. He1 , L. H. Khiem2 , S. Nishimura3 ,H. Ohta, A. Ozawa, Y. Tagishi, Y. Wakabayashi4 , M. Yamaguchi and T. Yasuno
We have been developing an experimental method to measure the α resonant scattering and the (α,p)
reactions with the thick-target method [1] in inverse kinematics using a room-temperature helium gas
target. This method enables us to study the α-induced reactions of unstable nuclei which are only available
as secondary beams. In order to establish the experimental method to measure the α resonant scattering,
we performed an experiment of α+16 O elastic scattering at the University of Tsukuba Tandem Accelerator
Center (UTTAC). Figure 1 shows a schematic view of the experimental setup. An 16 O beam of 40 MeV
was supplied by the 12UD Pelletron tandem accelerator. In the beam-monitoring section, the beam wascollimated by a double-collimator system. A carbon foil was set after the collimators. A silicon detector
was set at 12 degrees with respect to the beam direction in order to measure the beam current using the
16 O+12 C elastic scattering. The setup for measuring the α resonant scattering is shown in the target sectionin Fig. 1. Helium gas at room temperature was used as a target. The gas was confined by a Havar foil atthe entrance of the target section. The pressure of helium gas was adjusted so as to stop the beam particles
before the telescope in the gas. The energy of the 16 O beam decreased down to 32.5 MeV after the Havar
foil. A telescope consisting of two position sensitive silicon detectors (PSD1 and PSD2) and a pad silicondetector (SSD) was set on the rotatable table to cover a certain range of scattering angle inside the gas.
The recoil α particles were identified by the ∆E-E method.
beam−monitoring section
100 µg/cm2
C

O

PSD1: 0.02 mm
PSD2: 0.074 mm
SSD: 1.5 mm

310 mm12
16

target section
Havar foil
2.2µm, 20 mmφ12o

16O+α elastic scat.
θlab.=0 oz

θSiFaraday cup
470 Torr He gas
collimator
beam monitor

0o < θSi < 45o

Si telescope

Fig. 1. Schematic view of the experimental setup.

Fig. 2. The R-matrix fit to the
0 deg. data.

The R-matrix calculation was performed to the experimental data. Figure 2 shows an energy spectrumof α particles measured by the strip at 0 degree. The red line shows the experimental data. The blue
one corresponds to the R-matrix calculation including the experimental resolution. Several peaks wereobserved which correspond to known levels in 20 Ne [3].
1 Center for Nuclear Study, University of Tokyo
2 Institute of Physics and Electronics, Vietnum
3 RIKEN
4 Department of Physics, Kyushu University

18

Figure 3 shows the correlation between the energy and the scattering angle of the recoil α particles.
The vertical axis is the energy of the recoil α particles at the telescope, whereas the horizontal axis is
the scattering angle in the center-of-mass system. The scattering angle was determined by taking thekinematics and the energy losses of the incident and the recoil particles into account. The dotted curves
are the calculations which well reproduce the experimental data. Figure 4 shows an example of the angular
distribution of the recoil α particles for the 10.55 MeV 4+ state in 20 Ne. The data has a good agreementwith |P4 (cos θαc.m. )|2 .

Fig. 3. Correlation between the energy and thescattering angle of the recoil α particles.

Fig. 4. Angular distribution of the 10.6 MeV
4+ state in 20 Ne.

In the present study, the experimental method for the α resonant scattering was developed using theroom-temperature helium gas target and the inverse kinematics. The R-matrix analysis of the data showed
good agreements with the resonance parameters known for the excited states in 20 Ne. This method will
be applied to α resonant scattering experiment using RI beams.

References[1] S. Kubono, Nucl. Phys., A693, 221 (2001).
[2] M. Notani et al., Nucl. Phys., A738, 411 (411).
[3] D. R. Tilley et al., Nucl. Phys. A636, 249 (1998).

19

2.7

Measurement of timing resolution for plastic scintillation counters in
vacuum

Y. Hashizume, A. Ozawa, T. Nagatomo1 , and T. Yasuno
Measurement of time-of-flight (TOF) with good timing resolution is necessary for particle identification for radioactive isotope (RI) beam experiments. Plastic scintillation counters are widely used tomeasure TOF. In order to avoid energy losses of beam at vacuum windows, it is appropriate for detectors to be operated in vacuum. A commercial photomultiplier tube (PMT) assembly, Hamamatsu H6533,
which has a good timing response, can not be operated in vacuum because of outgas [1].
We constructed new plastic scintillation counter assemblies to be operated in vacuum using PMT,
Hamamatsu R4998. The plastic scintillator of BC408 with dimension of 50×50×0.6 mm3 was coupled to
the PMT with a light guide. The measurement of intrinsic timing resolution of the counter was performed
at 2E course (NASS chamber) in the 12UD tandem accelerator of UTTAC using 17MeV proton beam.
Fig.1 shows the experimental set up. Two identical counters located inside the NASS chamber have been
operated in vacuum around 10−7 Torr for 7 hours without any change of vacuum condition or fluctuationsof pulse shape from the counters. The beam intensity was typically 1nA. The proton beam was elasticallyscattered at 1µm Au foil. The counting rate of the elastically scattered ions can be changed by selecting
the scattering angle. The signals from upstream and downstream counters were connected to the TDC
start and stop inputs, respectively. A typical TOF spectrum is shown in Fig.2.

105mm

23mm

210mm

17MeV proton beam
3mm φ

1µm Au foi(scattering terget)~10mm φscatt.
angle θ3mm Al(collimator)

0.6mm BC408
covered with 12µm Al foil
(Upstream Scinti.)

0.6mm BC408
covered with 12µm Al foil
(Downstream Scinti.)

Disc.

Disc.

TDC start

Delay

TDC stop

Fig. 2. A typical TOF spectrum between the
upstream and downstream counter. The
spectrum is fitted by a Gaussian shape.

Fig. 1. The experimental set up.

1 RIKEN (The Institute of Physical and Chemical Research), Wako, Saitama 351-0198, Japan20

Intrinsic timing resolution σint can be estimated by σT OF obtained from the TOF spectra. If performance of the two counters is identical, the following equation is fulfilled;
1 2
σT2OF = σint
2

(1)

The typical σint was 130ps in sigma. High voltage (HV) and counting rate dependences of σint are shownin Fig.3 (a) and (b), respectively. Note that HV of downstream counter was fixed at -2000V in Fig.3 (a)and that HV of both upstream and downstream counters were fixed at -2400V in Fig.3 (b).
In the RI beam experiments, σint can become smaller since the atomic number of the beam is larger
and more light output from the plastic scintillator is available. Thus we conclude that our counters can beused for particle identification of RI beam experiments.

timing resolution sigma(int) [ps]230(a) HV dependence of upstream counter

220
210
200
190
180
170
160
150
140
-1700 -1800 -1900 -2000 -2100 -2200 -2300 -2400 -2500 -2600
HV of upstream counter [V]timing resolution sigma(int) [ps]133(b) coincidence counting rate dependence

132
131
130
129
128
127
126
101

102
coin. counting rate [cps]103

Fig. 3. HV (a) and counting rate (b) dependences of σint . HV of downstream counter was fixed at -2000V
in (a). HV of upstream and downstream counters were fixed at -2400 in (b).

References[1] R. Kanungo et al., RIKEN Accel. Prog. Rep. 35 (2002) 164

21

2.8

Particle identification using pulse shape analysis

M. Kurokawa1 , H. Baba1 , M. Yamaguchi1 , S. Nishimuara1 , T. Fukuchi2 , A. Ozawa, and H. Tagishi1
To identify charge and mass numbers of nuclei, 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 of chargecollection time with charge and mass number for nuclei with the same energy. The increase is associatedwith a longer distance between an electrode on the junction side and the position where an incident particle
induces the ionization with the highest density. Since the idea was realized by Pausch et al.[?] for the
first time, different analyzing methods of the pulse shapes have been examined for these ten years. In
spite of these efforts, the discrimination in a low energy region is deteriorated because of an unexpectedphenomenon, which is an opposite dependence of the charge collection time on the distance. The lower
limit of 2.5 MeV has been reported for the discrimination between the proton and alpha particles.
To understand the reason and to improve the capabilities for the technique, beam test was performed at
the TANDEM accelerator at the University of Tsukuba. Incident energy of a 3 He beam was 30 MeV, andthe scattered particles by a Ag target were identified with the ∆E-E method consisting of two Si detectors.
The E detector was mounted so that the ohmic side was irradiated and was biased as much voltage as
required for total depletion. The junction side is divided into 4 strips. To record the pulse shape from astrip, the signal of the preamplifier was coded by a sampling ADC(SIS3301) with a resolution of 14 bit
and 100 MSamples/s. The starting time of the recorded pulse shape is given by the ∆E detector, which
was over biased to obtain good timing information. For thus recorded pulse shape, the relation between
the deposited energy in the E detector and the averaged rise time is shown in Fig. 1 for light charged
particles. Here, the rise time is defined as the time when the magunitude of the pulse reaches 60% of its
maximum height. The energy was obtained by the trapezoidal shaping. Larger error bars for particles with
their atomic number of 2 are due to the lower statistics. As seen in the figure, the discrimination of the
proton and alpha particle is possible down to an energy of 1 MeV. The more accurate determination of thestarting time of signals will achieve the better performance of the particle identification.

References[1] G. Pausch et al.: IEEE Trans. on Nucl. Sci. 43, 1097 (1996).

1 RIKEN
2 Rikkyo Univ.

22

Fig. 1. The relation between the energy and the rise time (see in the text) is shown for light charged
particles as indicated in the figure.

23

3.
ATOMIC AND SOLID STATE PHYSICS,
AND
CLUSTER SCIENCE

3.1

Evolution of resonant coherent excitation of hydrogen-like fast ions

H. Wakamatsu, S. Tomita, S. Kanda and H. Kudo
We have previously observed resonant coherent excitation (RCE) applying 180˚ electron spectroscopy
for detection of K-shell electrons ionized from projectile C5+, that are enhanced by RCE [1]. Thisobservation technique allows studies of RCE at an extremely thin layer of crystal surface where RCEdevelops with increasing the number of encountering aligned atoms n. Furthermore, we may use bulk
crystals, rather than self-supported crystal foils, so that target preparation becomes much easier.

In thisreport, recent progress on the RCE studies is presented.
Figure 1 shows energy spectra of electrons induced by 4.84 MeV/u O7+ and O8+ incident on Si crystals
under Si<110> channeling incidence conditions. The yield is shown for the same number of the incident
projectiles and, accordingly, the excess electron yield for O7+ at energies lower than the loss-peak energy
EL and higher than the Si K-shell Auger peak at ~1.5 keV is due to the ionized K-shell electrons from O7+.
The lower yield for O7+ below ~1.1 keV stems from the suppressed electron emission by the screened
Coulomb field of O7+ compared with the pure Coulomb field of O8+.
18

4.84 MeV O on Si<110>

16

Intensity (arb.unit)

14

7+

O

12
10
8

8+

O

6
4
2

EL

0
0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Electron energy (keV)

Fig. 1 Energy spectra of electrons induced by 4.84 MeV/u O7+ and O8+
under Si<110> channeling incidence conditions.
Figure 2 shows the dependence of the loss electron yield as a function of incident O7+ energy. We see a
sharp resonance peak at the calculated resonance energy of 4.75 MeV/u. The peak results from theenhanced ionization of K-shell electrons of O7+ under the RCE conditions for the second harmonics.
In the first order perturbation, the transition probability of RCE is given by,

q (n, T ) =

2
1 nT
′
φ
H
(
τ
)
φ
exp(
i
ω
τ
)
d
τ
2
1
0
h 2 ∫0=2
D ( n, T ) T
′
φ
H
(
τ
)
φ
exp(
i
ω
τ
)
d
τ
2
1
0
h 2 ∫025,(1)where T, the interatomic spacing divided by the ion speed, is the period of perturbation, ω0 is the angularfrequency corresponding to the excitation energy from φ1 (n=1) to φ2 (n=2) states, H′ (τ) is the screened
Coulomb potential exerted from a Si atom, and D(n, T) is the diffraction function, i.e.,D ( n, T ) =sin 2 ( nω0T / 2).
sin 2 (ω0T / 2)

(2)

It is noted that in this treatment we have assumed straight-line trajectories of the ions in the Si crystal,
which holds only for well channeled ions.
0.03

116000

11
31
51
71
91
111
131
151
171
191
sum/20f (Ee=2.04keV, x) (arb. unit)

Electron yield (counts)

peak 4.75MeV/u

106000
96000
86000
76000
66000
56000
4.50 4.55 4.60 4.65 4.70 4.75 4.80 4.85 4.90 4.95
O7+ incident energy (MeV/u)

Fig. 2 Dependence of the loss electron yield as a
7+

0.02

0.01
Δx/x=0.51%

0.00
6.20

6.24

6.28

x=ω0T/2

6.32

6.36

Fig. 3 Calculated resonance curve (squarefunction of incident O energy. The RCE peak isdots) of RCE for the second harmonics,

seen at the calculated resonance energy of 4.75

which are constructed from eq. (2) for
various n (shown in solid lines).

The loss electrons generally undergo elastic and inelastic collisions in the escape paths to the surface.
Such processes can be reproduced numerically by semi-classical calculations [2]. Actually, we cancalculate energy spectra of K-shell electrons emitted from the surface after suffering elastic and inelastic
collisions in Si as a function of the depth where K-shell ionization occurs. In this manner, we may obtainthe loss electron yield against the incident ion energy, i.e., the resonance profile of RCE. The results for
2.04-keV electron emission are shown in Fig. 3. The full width at half maximum of the RCE peak,Δx/x=0.51%, corresponds to ⊿E/E =2(Δx/x)=1.02% in the energy space. This value is in good agreementwith the observed value of ⊿E/E = (0.96±0.15)%. It is therefore evident that the evolution of RCE canessentially be accounted for in terms of the development of diffraction in the time space.
References[1] H. Kudo, M. Nagata, H. Wakamatsu, S. Tomita, Nucl. Instrum. & Methods, B 229 (2005)227.
[2] S. Valkealahti, R. M. Nieminen: Appl. Phys. A 32, (1983)95.

26

3.2

Vicinage effect in the yield of convoy electrons under irradiation of
fast carbon cluster ionsS. Tomita, S. Yoda, R. Uchiyama, S. Ishii, K. Sasa, and H. Kudo
When closely-spaced atoms e.g. clusters are incident on a surface, the interference in the collisioninduced processes by the neighbor atoms can affect the emission of secondary particles. This is called
the “vicinage effect”, which has been observed for fast molecular or cluster ion beams [2]. We performed
measurements of a vicinage effect in the yield of convoy electrons, which provides information concerning
the number of primary scattered electrons under cluster irradiation.
Beams of carbon cluster ions were delivered by the 1 MV tandem accelerator at the University ofTsukuba. The cluster ions from the accelerator impinged on an amorphous carbon foil where a voltage of
V = −50 V was applied. About 1 cm downstream from the target, a grounded plate was placed, so that theemitted electrons in the forward direction were accelerated and detected in an electron spectrometer. The
spectrometer is a 45◦ parallel-plate electrostatic spectrometer of the double deflection type. The electrons
were counted by a channeltron detector whose anode potential was set to 200 V to increase the detection
efficiency of low energy electrons. The energy of the carbon clusters C+
n (n = 1 to 4) was 0.5 MeV/atom,and the beam current was a few pA. The foils used were purchased from Arizona Carbon Foil, and had
thicknesses of 1.8, 5.6, 11.0 and 19.3 µg/cm2 . The vacuum pressure was ∼ 5 × 10−6 Pa during the beamirradiation.

Fig. 1. Energy spectra of secondary electrons produced by irradiation of C+ (solid line), C+
2 (dash line),+
2 carbon foil. Arrow indicates the energy ofC+(dotline),
andC(dash-dot
line)
on
a
5.6
µg/cm
3
4
electrons which have same velocity as the projectile ions.

Typical energy spectra of the emitted electrons are shown in Fig.1. The spectra were normalized to
the number of injected atoms instead of the number of cluster ions. The negative vicinage effect, i.e., thereduced electron yield for cluster injection, is clearly recognized at energies Ee < 150 eV while the yieldfor cluster injection is larger around the peak located at Ee ∼ 23 eV. The reduction of the electron yield at
low energies are also observed in backward electron emission [3]. The peak at Ee ∼ 23 eV corresponds27

to electrons which have the same velocity as the projectile ions, i.e. convoy electrons. The position of the+peak does not depend on the cluster size, but the area of the peak is enhanced for C+
4 relative to C1 , incontrast to the negative vicinage effect observed in the continuum yield (Fig.1).

Fig. 2. Yield of convoy electrons produced by 0.5 MeV/atom C+
n ion bombardment of 1.8 (open squares),
5.6 (open circles), 11.0 (open triangles), and 19.3 µg/cm2 carbon foils (open diamonds). Lines arefrom a least square fits.

In Fig.2, the size dependence of the convoy electron yield is shown for the four different carbon foil
thicknesses. It is interesting that the yield per injected atom shows a clear proportionality with n. The
yield for C+ decreases for thick foils but the proportionality still remains even for the thickest foil of
19.3 µg/cm2 . This observed proportionality can be understood if the convoy electrons stem from electron
capture of primary scattered electrons to the continuum state of the projectile ion. The results obtained
for the yield of the convoy electrons suggest that the number of scattered electrons is proportional to thenumber of projectile atoms. This leads us to conclude that the strong vicinage effect in the continuum
spectra stems from either electron transport inside the foil or transmission through the surface.

References[1] M. Breinig et al., Phys. Rev. A, 25, 3015 (1982).
[2] D. Jacquet and Y. Le Beyec,Nucl. Instr. and Meth. in Phys. Res. B 193, 227 (2002).
[3] H. Kudo et al., Jpn. J. Appl. Phys. (2006), in press.

28

3.3

Mösbauer study on γ-Fe2 O3 thin films

M. Hasegawa, K. Shibata, H. Yanagihara, E. Kita
γ-Fe2 O3 (maghemite) has been used as magnetic recording media. However, the physical properties
are not well understood because this iron oxides is in a metastable state and it is hard to grow the single
crystals. Crystal structure of γ-Fe2 O3 is believed to be close to Fe3 O4 (magnetite); an inverse spinel ferrite2−
3+
of which one third of the B-site irons are vacant. It is frequently written as Fe3+
A [Fe5/3 X1/3 ]B O4 (Xstands for Fe vacancy). Consequently, the maghemite is expected to be an insulator and to show small
magnetic anisotropy due to no orbital angular momentum. Recently, the growth techniques for γ-Fe2 O3
epitaxial films were developed by several groups[1, 2]. An x-ray diffraction analysis revealed that the unit
cell of the grown film is three times larger than that of Fe3 O4 [2] and that the B-site vacancies are fullyordered with c-axis parallel to the film growth direction. Most of physical properties, however, are still
unrevealed.
We report magnetic properties of γ-Fe2 O3 epitaxial films on MgO(001). The film growth method canbe found in Ref.[2]. The typical thickness of the films reported here was around 100 Å. Ferromagnetic
resonance (FMR) were carried out. A frequency of the microwave for FMR measurements was 9.75
GHz. The FMR experiments were performed with the static field applying parallel to the (001) plane. We
performed conversion electron Mössbauer spectroscopy (CEMS).
Fig. 1 shows in-plane angle θ dependence of the resonance field. θ was defined as the angle between[100] and applied static field direction in (001) plane. This result indicates that the in-plane [110] and[100] directions seem to be magnetic easy and hard axes, respectively.
2300

Hr (Oe)

2250

2200

2150

2100
0

30

60

90

120

150

180

θ (degree)

Fig. 1. The angle θ dependence of the resonance field(Hr ). θ was defined the angle between [100] and thestatic field direction. The solid line stands for the fit result with equation(1). Two-fold component
due to a small misalignment is subtracted from the raw data.

Moreover, γ-Fe2 O3 possibly shows uniaxial magnetic anisotropy associated with the three-fold tetragonal crystal structure[2]. Therefore in-plane four-fold symmetric anisotropy and the additional out-ofplane uniaxial anisotropy can coexist. In order to extract both constants of cubic anisotropy(K1 ) anduniaxial anisotropy(Ku ), we quantitatively analyzed θ -dependent FMR data using the resonance condition

29

1.12

Relative Emission

1.10
1.08
1.06
1.04
1.02
1.00
0.98
-12

-8

-4

0

4

8

12

Velocity (mm/s)
Fig. 2. Conversion Electron Mössbauer Spectrum(CEMS) of γ-Fe2 O3 films with the thickness of around70 Å recorded at room temperature.

derived from Ref. [3]. K1 and Ku were estimated to be -1.3×105 and 3.0×105 erg/cm3 , respectively. The
sign of Ku is positive, suggesting that energetically perpendicular preferential term exists but is smaller
than the demagnetization field.
In Fig. 2 the spectrum of CEMS for 70 Å thick γ-Fe2 O3 film at room temperature. The sample forthis experiment was prepared with 57 Fe enriched source. The spectrum of the simple sextet also supportsthat the film is not composed of the mixture of Fe3+ and Fe2.5+ (Fe3 O4 ) but of only Fe3+ (γ−Fe2 O3 ).
Note that the relative intensity ratio of the six lines is slightly apart from an ideal thin film magnet with amagnetic preferential direction parallel to the film plane. Theoretically, the six lines relate as 3:x:1:1:x:3,
x=4sin2 ϕ/(1+cos2 ϕ). ϕ means the angle between the incident γ-rays and the direction of the magnetic
hyperfine field. The estimated angle ϕ is about 60 degree, suggesting the zero-field magnetization has afinite normal component to the plane which is qualitatively in agreement with the results of Voogt et al.[1].

References[1] F. C. Voogt, T. Fujii, P. J. M. Smulders, L. Niesen, M. A. James and T. Hibma, Phys. Rev. B 60
(1999) 11193.
[2] H. Yanagihara, M. Hasegawa, E. Kita, Y. Wakabayashi, H. Sawa, and K. Siratori, J. Phys. Soc. Jpn.
75 (2006) 054708.
[3] A. H. Morrish, The physical principles of magnetism (Wiley-IEEE Press, 2001) p542.
[4] G. Bate Magnetic Oxides ed. D. J. Craik, Wiley, London, (1975) p.689.

30

3.4

The science of 3d transition-metal oxide system (2005–2006)

M. Onoda, T. Ikeda, K. Takao, Y. Kikuchi, A. Sasaki, Y. Ishitsuka, W. Onoda, T. Maekoya, Y. Mizuguchi
and N. Yamazaki
The structural and electronic properties of 3d transition-metal oxides and bronzes have been exploredby means of x-ray four-circle diffraction and through measurements of magnetic resonance (NMR and
ESR), magnetization, and electronic transport, in order to extract characteristic properties in the quantum
spin-fluctuation system, correlated electron system, electron-phonon-coupling system, and novel materials such as a new type of superconductors, composite crystals and secondary ion batteries [1-4].
At the Tandem Accelerator Center, Varian continuous-wave and Bruker pulse NMR spectrometers havebeen used. This report describes briefly recent progress for the secondary ion battery system [1, 3, 4].
Typical insertion electrode systems for vanadium oxides, Li1+x V3 O8 and Lix V6 O13 , can accommodate around three or four additional Li ions per formula unit of LiV3 O8 and eight ions per V6 O13 , respectively. These lithiations may supply new kind of compound series for the investigation on quantum-spin
fluctuation and correlated electron systems. In order to construct this situation and to improve battery
performances, the basic properties as a function of the Li concentration have been studied. The cw-NMR
results for the linewidths of 7 Li nuclei in Li1+x V3 O8 were understood successfully as described in a reportin 2004–2005. In this report, the MAS-NMR results for Li1+x V3 O8 with x = 0, 0.25 and 3.2, the last composition being prepared electrochemically, measured at 233.23 and 116.61 MHz between 240 and 390 K
are discussed.
The central spectra are decomposed to two or three Lorentzians assuming axial or isotropic contribution for the shift. Here, it should be noted that for Li1 with x = 0, the second-order quadrupole effectcan be neglected. For x = 0, there exist two resonance lines named A and B. Using the relative intensity
for each line, the Li concentrations normalized to the nominal value against temperature are estimated asshown in Fig. 1(a). The Li concentrations do not depend on temperature, and the A- and B-lines may
be attributed to the signals from Li1 and Li2 sites, respectively, since the Li2 ion appears to exist slightly
even when the nominal concentration is fixed at x = 0. Note that the slight occupation of Li2 gives rise to
unpaired spins for V ions. The temperature dependences of the shifts and the spin-lattice relaxation times
for x = 0 are indicated in Figs. 1(b) and 1(c), respectively. The shift for Li2 is almost zero, but that forLi1 increases negatively with decreasing temperature. The latter result may correspond to a sum of thehyperfine shift via the Fermi contact interaction and temperature-independent terms. The hyperfine shift δdepends linearly on the magnetic susceptibility, δ = Hhf χ/(NµB ), where Hhf , χ, N and µB are the hyperfine field, the susceptibility, the number of magnetic V ions and the Bohr magneton, respectively. The fullcurve in Fig. 1(b) provides Hhf = −26(3) mT µB−1 . The origin of the negative Hhf value or the spin transfer
mechanism may be originated by spin polarization effects due to the exchange interactions. The T1 for
Li1 with x = 0 is linear in temperature, which suggests that the relaxation is of the quadrupole type for therotational motion of Li ions. With the extreme narrowing condition and the nuclear spin I = 3/2, this is
written by 1/T1Q = 10−1 (1 + η 2 /3)(e2 qQ/h)2 τc , where τc is an effective correlation time for the motion
and it is proportional to the inverse of temperature. The full line in Fig. 1(c) leads to τc ' 7.9 × 10−7 /T
s. The T1 for Li2 seems to have a temperature dependence similar to that for Li1. It is not necessary31

to consider the hyperfine interaction for the main relaxation mechanism, since the relaxation rates of the
A-line for the different compositions are similar to that for x = 0.

#

!!"

$

Fig. 1. The temperature dependences of (a) the Li concentrations normalized to the nominal value; (b) theshift; and (c) the spin-lattice relaxation times for 7 Li nuclei in LiV3 O8 .

For x = 0.25, three resonance lines (A, B and C) exist above 270 K and at 260 K, the D-line withmore negative shift appears. At the lower temperature, it is difficult to distinguish between the B- and Cline. The A- and B-lines are originated from the Li1 and Li2 sites, respectively, and the C-line may comefrom another tetrahedral Li site. Since the V ion is more reduced and the compound is more magnetic ascompared with those for x = 0, the hyperfine shifts for the Li1 and Li2 ions increase more negatively. The
Hhf values for Li1 and Li2 are −21(2) and −9(2) mT µB−1 , respectively. Below 260 K, these shifts show
opposite temperature dependences and the shift for D-line increases negatively. This result suggests theoccurrence of phase transition for the local environments of Li. The T1 ’s for x = 0.25 are the same orderwith those for x = 0, but their temperature dependences are weak due to an increase of the temperatureindependent contribution from the exchange coupled V ions via a transferred hyperfine interaction. Thereexist small anomalies above 260 K, at which the local environments of Li change. Details for x = 3.2 are
written in ref. 1.
In summary, MAS-NMR spectra for the γ1-phase clearly reflect the site differentiation for Li. The
spin-lattice relaxation for x = 0 is explained with the quadrupole interaction mechanism. For x = 0.25,
the phase transition for the Li local environments occurs at 260 K with VRH-type transport anomaly.
The spectra for the γ2-phase are significantly different from those for the γ1-phase and the complicatedrelaxations are detected.

References[1] M. Onoda, S. Miyasaka, T. Mutoh and K. Nichogi: J. Phys.: Condens. Matter 17(26) (2005) 4057–
4071.
[2] M. Onoda and J. Hasegawa: J. Phys.: Condens. Matter 18(7) (2006) 2109–2123.
[3] Masashige Onoda and Mitsuko Onoda: Phys. Rev. B 73 (2006) 104108 [7 pages].
[4] M. Onoda: Ceramics 41(3) (2006) 167–172 [in Japanese].

32

3.5

Oxidations of cobalt clusters

M. Kubo, T. Sugaya, I. Arai and K. Sugawara 1
The oxidation reactions of metal clusters have been studied for many years to understand theirsize-dependent chemical properties and to gain insight into their reaction mechanism on metal surface
related to corrosion or catalytic processes.
With respect to reaction of nickel cluster cations with oxygen, the reaction products were observed after
101 to 103 collisions with O2 using FT-ICR mass spectrometry so far. It was found that the most abundant
final products were Ni13O8+ and Ni16O10+ which reacted with neither O2 nor H2O under the O2 pressure 10-6
to 10-4Pa and the reaction time 1 to 20 sec at room temperature.
In order to compare nickel with cobalt, the experiments of reactions of cobalt clusters with O2 havebeen carried out under the O2 pressure 10-6 to10-4Pa and the reaction time 0.1 to10 sec at room temperature.
We have searched the similarities and discrepancies between cobalt clusters and nickel clusters.
The experimental set up mainly consists of a laser vaporization cluster source and an FT-ICR mass
spectrometer. The cobalt cluster cations Con+ are produced by laser vaporization of rotating cobalt rod.
They are introduced into an FT-ICR chamber and trapped by collisions with O2, where the O2 pressure is
10-6 to10-4Pa. We have measured the mass spectra under the reaction time 0.1to 10 sec at room
temperature.
In these experiments, the most abundant final product was Co13O8+, which was similar to the case ofoxidations of nickel clusters. But, we could not find any stable Co16O10+. Further examination of such
similarities and discrepancies between the oxidation of Nin+ and that of Con+ is under progress now.

1

Nanotechnology Research Institute, AIST

33

3.6

Estimation of Eu concentration in Eu-doped GaN by RBS
measurements

J. Sawahata, J.W. Seo, S.Nemoto and K. Akimoto
Rare earth (RE) doped GaN thin films have attracted great interests due to their unique opticalproperties, that is, luminescence due to an intra 4f transition of RE ion depends very little on the hostmaterial and the temperature. Among the several RE dopants, it is well known that europium (Eu) shows astrong red emission around 622 nm. The Eu concentration in the films is a one of important parameters on
the optical properties of Eu-doped GaN. Therefore, we performed Rutherford back scattering (RBS)
measurements to estimate Eu concentration in Eu-doped GaN.
The Eu-doped GaN thin films were grown on GaN/Al2O3 substrates by molecular beam epitaxy
methods [1]. The RBS measurements were carried out using 1.5 MeV accelerated 4He ions with a tandem
accelerator placed at UTTAC. The geometry of incident angle, exit angle and scattering angle were 30, 0
and 150 degrees, respectively. A detector was placed at 70 mm from the sample surface.
Fig. 1 shows a RBS spectrum of Eu-doped GaN as an example. The spectrum heights of the edges
corresponding to scattering from the surface atoms were used for calculation of Eu concentration. In Fig.1,
the Eu concentration was estimated at 3 at.%. The red emission intensity of Eu-doped GaN increased up toan Eu concentration of 3 at.%, and then it decreased for Eu concentration of more than 3 at.%. Therefore,
wefound that an optimum Eu concentration on the optical properties of Eu-doped GaN is estimatedaround 3 at.% by RBS measurements.

1400

GaN:Eu/GaN/Al2O3

1200Counts

1000
800
600
400
200
0

0

200

400

600

800

1000

ChunnelFig. 1 RBS spectrum of Eu-doped GaN
References[1] H. Bang, S. Morishima, J. Sawahata, J. Seo, M. Takiguchi, M. Tsunemi, K. Akimoto, Appl. Phys. Lett.
85, 227 (2004)

34

4.
ION BEAM ANALYSIS AND APPLICATION

4.1

Status of Tsukuba AMS system

Y.Nagashima, K.Sasa, T.Takahashi, R.Seki, Y.Tosaki, K.Sueki, K.Bessho, H.Matsumura, T.Miura andK.Masumoto
In the last year, we lost several scheduled AMS measurements because of unexpected problems
happened on the 12UD tandem. In contradistinction to the last year, we could exhaust all of scheduled
AMS machine times with a successful results this year. In parallel with the AMS measurements, aperformance improvement of an AMS ion source system has been done. We report, first, the improvement
done in this year, and second, the experimental results are reported briefly.
The dating of ice core sampled at the Fuji dome in the Antarctica Continent as a big national
project is commenced. The depth of the ice bed at the Fuji dome is about 3,000m and the core samples arecollected from the surface to the 3,000m depth. It is estimated that the age of the core sample at the
3,000m depth is ∼100 million years old. Therefore, it is expected that the core sample memorizes therecord of not only an environmental change of the earth but also a change of a solar activities for the 100
million years. To investigate and to understand the change, the measurement of 36Cl element in the icecore has been commenced by mean of 36Cl-AMS.
A calculated fall out of the 36Cl on the ice bed is ∼60 atoms/m2/s and the number of the 36Cl in
the ice core is ∼6×103 atoms/g. The 36Cl/Cl ratio is estimated to be the range from 10-14 to 10-15. To
accommodate lowering the 36Cl/Cl ratio, several improvements has been performed in the AMS ion source.
A 120° ion source magnet was newly designed and replaced with an old one for improving a beamdisplacement. Fig. 1 shows outline of the new 120° magnet. The size of the 35Cl beam is decreased from∼4mm to ∼2mm in diameter. The small displacement makes an efficiency and stability of a beamtransmission in the accelerator tubes better.
The beam optics for the ion source has been calculated again for finding out the optimum
operating condition. The best condition we got is shown in Fig. 2. As a result of the calculation, we
understand that the shape of both an ionizer and an extraction electrode are not ideal. Therefore, they were
replaced with newly designed ones and, consequently, the 35Cl- ion current increased and reached to∼40μA. The strong 35Cl current helps very much to realize the measurement of the samples with verysmall 36Cl/35Cl ratio.
The first East Asian AMS Symposium (EAAMS-1), and the 8th Japanese AMS Symposium(JAMS-8), have been organized by the Tsukuba AMS group and successfully concluded. It was attended
by 120 peoples from 4 countries which are Korea, China, USA, and Japan. The contributions to thesymposiums, both technical and applied, clearly demonstrated that AMS has evolved into a versatile tool
to study our world, especially our East Asia. The Proceedings of both Symposiums contain 44 papers
covering a large fraction of the contributions presented at the symposium. The second East Asian AMS
Symposium will be held in Korea in 2007.

35

Fig.1 Picture and drawing of the120° magnet for the ion source

Fig. 2 Calculation of Cs+ beam trajectories and 36Cl- beam envelope at the ion source andan einzel lens. The diameter of the Cs+ beam spot on the target is about 2.6mmφ.

36

129

4.2

I-AMS by the Tsukuba AMS system

K. Sasa, Y. Nagashima, T. Takahashi, R. Seki, Y. Tosaki, K. Sueki, B. H. Zhou
A 97Mo16O2 molecular pilot beam method is applied to the 129I measurement by the Tsukuba AMS
system [1]. The ions extracted from the ion source are selected by a 120° mass separator. The beam
current of 127I− is measured by an off-set Faraday cup just set at an image of the 120° mass separator
simultaneously with the 129I ions in the detector. 129I− and 97Mo16O2− ions are accelerated concurrently and
129 12+Iand 97Mo9+ can pass through the 90° analyzing magnet. Once the analyzing magnet is adjusted for

129 12+ 97

I , Mo9+ ions pass through about 5 mm down at an image point of the magnet and produce the slit

current for the slit current feedback terminal potential stabilizer. A magnetic rigidity of 97Mo9+ is almost
the same as that of 129I12+, so that a second stripper foil is prepared in an AMS beam line in order to sweepout the 97Mo9+ ions. After passing through the second stripper foil, 129I26+ is selected as a detection particle.
On the other hand, no 97Mo particles can enter the detector because the magnetic rigidity of 97Mon+ isdifferent from that of 129I26+. Finally, 129I26+ ions are clearly detected by a silicon surface barrier detector.
The terminal voltage is set to 9.68 MV in order to get most efficient yields of both 129I12+ and 129I26+. Fig. 1
shows the one-dimensional spectrum for 129I measurement. A standard sample was prepared from the
NIST standard.
At present, we plan to measure 129I concentrations in soils of the Semipalatinsk nuclear explosion testsites in Kazakhstan in collaboration with the Hiroshima University.
129

I-AMS

10000

Standard sample
129I/127I = 4.9 × 10−10

Yields (counts)

1000

Mo

129I

100

10

1
0

200

400

600

800

1000

Particle energy (channels)

Fig. 1. One dimensional spectrum for a standard sample with a ratio of 129I/127I = 4.9 × 10−10 measured by asilicon surface barrier detector. 129I is clearly separated from the isobaric ions.

References[1] K. Sasa, Y. Nagashima, T. Takahashi, R. Seki, Y. Tosaki, K. Sueki, K. Bessho, H. Matsumura, T. Miura,
S. Jiang and M. He, Proceedings of the First East Asian Symposium on Accelerator Mass Spectrometry,
UTTAC-74 (2006) 69-80.

37

4.3

Test measurement of 36Cl concentration in an ice core retrieved
from the Dome Fuji station in Antarctica.
1

K. Sasa, Y. Tosaki, Y. Nagashima, T. Takahashi, R. Seki, K. Sueki, B. H. Zhou, K. Bessho ,H. Matsumura1, T. Miura1, Y. Shibata2 and H. Motoyama3
In 2006, Japanese glaciological group succeeded in drilling the deep ice core with a depth of 3028 m
at the Dome Fuji station on the one of summits of East Antarctica. AMS group of the University ofTsukuba takes part in the joint research project for analyzing the cosmogenic radioisotopes 10Be (T1/2 =1.51 × 106 years), 26Al (7.16 × 105 years) and 36Cl (3.01 × 105 years) in the ice core retrieved at the Dome
Fuji station in collaboration with National Institute of Polar Research, National Institute for Environmental
Studies, Hirosaki University and the University of Tokyo. The concentrations of cosmogenic radioisotopes
in the ice core provide useful information about the history of the cosmic ray flux in the atmosphere, thepast solar activity and the past earth environment such as changes in the geomagnetic field.
We measured 36Cl concentration in a test sample retrieved as ice chips at around 100 m depth at theDome Fuji station previous to the regular AMS measurement. The age of the test sample corresponds toabout 2 kyr B.P.. The sample melted from ice chips with 505.9 g weight was used for this test
measurement. After adding 0.92 mg of stable chlorine as carrier to the sample, 36Cl and the carrier wereextracted together by means of anion exchange resin. The sample treatment is described elsewhere indetail [1]. The sample was formed as AgCl and pressed on the aluminum cathode. It was analyzed byusing the Tsukuba AMS system [2]. The effective detection limit is reached to 1.5 × 10−14 for 36Cl/Cl ratio.
The result of 36Cl measurement is presented in Table 1. The measured 36Cl/Cl ratio is 2.49 × 10−13. The
Cl concentration in the test sample corresponds to 7,680 atoms g−1. This result means that the Tsukuba

36

AMS system has an excellent performance to analyze the 36Cl concentration in the ice core with the rangeof the past million years.
Table 1. The result of 36Cl measurement in a test sample retrieved as ice chips at around 100 m depth.
36

Cl/Cl

error

Cl [mg/g]

36

Cl [atoms/g]

error

2.49E−13

3.20E−140.0018

7.68E+03

9.88E+02

Acknowledgements
This work is supported in part by the Grants-in-Aid for Scientific Research Program of the Ministry of
Education, Culture, Sports, Science and Technology, Japan.
References[1] Y. Tosaki and R. Seki, this annual report.
[2] K. Sasa et al., Proceedings of the First East Asian Symposium on Accelerator Mass Spectrometry,
UTTAC-74 (2006) 69-80.

1

Radiation Science Center, High Energy Accelerator Research Organization
National Institute for Environmental Studies
3
National Institute of Polar Research
238

Bomb-produced 36Cl in the Oderbruch aquifer, Germany: A
preliminary result

4.4

Y. Tosaki, N. Tase, G. Massmann 1 , Y. Nagashima, R. Seki, K. Sasa, T. Takahashi, B. Zhou, K. Sueki, K.
Bessho2, H. Matsumura2 and T. Miura 2
The potential use of bomb-produced 36Cl as a dating tool for modern groundwater has been
investigated recently [1,2]. As a result of these studies, bomb-produced 36Cl was suggested to be a usefultracer in groundwater. However, previously measured groundwater samples correspond to tail part ofbomb pulse period and pre- or post-bomb period [2,3]. For further investigation on bomb-produced 36Cl asa dating tool, measurement of groundwater of bomb peak period is necessary. In August 2005, newsamples were collected from same wells and some additionally installed wells. These samples wereprepared as AgCl and 36Cl/Cl ratios were measured by the500

samples is reported here.
The result of 36Cl measurement of 2005 samples is400

distributions of 36Cl/Cl ratios along the flow path of

0500

chloride concentration in groundwater becomes low ataround 2500–3000 m. However,3

Cl/Cl ratio could be

3

Shallow wells
Deep wells

300
200
100
0
4000

36

changed by the addition of chlorine from other sources.

400

−

36

mixing of rainwater from the ground surface, because

Cl/Cl (10 15)

groundwater are in fair agreement. Although higher

from the result. There may be some influence from

(b)

200
100

2500–3000 m apart from the river Oder, it was not clear

Shallow wells
Deep wells

300

compared with that of 2003 samples in Fig. 1. These twovalues (near the bomb peak) had been expected at around

(a)

−

36

Tsukuba. Preliminary result of 36Cl measurement of these

Cl/Cl (10 15)

AMS at the Tandem Accelerator Complex, University of

3000

2000

1000

0

Distance from the river (m)36Fig. 1. Cl/Cl ratios for Oderbruch samples

The H/ He measurement of same groundwater samples

as a function of the distance from the Oder.

will be conducted soon, therefore, detailed discussion willa) 2003 samples. b) 2005 samples. Shallow

3

3

be made with H/ He result.

well indicates upper part of the aquifer anddeep well indicates lower part.

References[1] Y. Tosaki, N. Tase, Y. Nagashima, R. Seki, T. Matsuhiro, T. Takahashi, K. Sasa, M. He, K. Sueki, T.
Miura, K. Bessho, H. Matsumura, UTTAC Annual Report 2003 (2004) 71.
[2] Y. Tosaki, N. Tase, Y. Nagashima, R. Seki, T. Takahashi, K. Sasa, K. Sueki, T. Matsuhiro, M. He, T.
Miura, K. Bessho, H. Matsumura, G. Massmann, UTTAC Annual Report 2004 (2005) 35.
[3] J. Sültenfuß, G. Massmann, Grundwasser 9 (2004) 221 (in German with English abstract).
12

Department of Earth Sciences, Free University of Berlin, Germany
Radiation Science Center, High Energy Accelerator Research Organization

39

4.5

Improvements in sample preparation for 36Cl-AMS

Y. Tosaki and R. Seki
Our previous sample preparation scheme [1,2] was basically developed referring to such as Conard etal. [3]. The scheme is very straightforward, but in case of groundwater, rainwater and ice samples,
concentration of sample solution is frequently required. For these large-volume samples, evaporative
concentration by heating had been employed. However, there may be a risk of sample contamination fromthe atmosphere during evaporation process. Additionally, sulfur reduction process included in the previous
scheme (i.e. removal of sulfur as BaSO4 precipitate) is time-consuming [4], while it is not effective
enough for our 36Cl AMS measurement of natural samples. For improving these problems, anion-exchange
column method was tested because large-volume samples can be readily processed with minimum risk ofcontamination. Another advantage to be expected is the separation of sulfur through the elution process [5].
With this new method, total time required per sample is much less than previous method.
AG 4-4X anion-exchange resin in the free-base form (100–200 mesh; Bio-Rad Laboratories, Hercules,
CA, USA) was used for our test experiment. First of all, 20 mL (wet volume) of the resin is transferred toa 60 mL Bond Elute column (Varian, Harbor City, CA, USA). Before use, the resin is cleaned by passing 4
M HNO3 through the column. After neutralization with Milli-Q water (better than 18 MΩ⋅cm; Millipore,
Billerica, MA, USA), the resin is conditioned by 0.5 M NH4OH and 2 M NH4OH. The resin is neutralizedagain with Milli-Q water, and then it is ready to use.
Anion-exchange column method was tested for a blank sample (NaCl reagent) and an ice sample from
Dome Fuji, Antarctica. As for the blank sample, about 0.91 mg of Cl (1.5 mg as NaCl) was dissolved in
500 mL of Milli-Q water. Similarly, 0.92 mg of Cl carrier was added to 506 mL of melted ice sample.
These solutions were acidified with the addition of HNO3 (pH ~2) and run through anion-exchange
columns (Fig. 1). After finishing this process, 0.5 M HNO3 was passed through the column, and then Cl
was eluted with 3 M HNO3. From this step, procedure is similar to previous method. In order to precipitate
AgCl, 0.3 M AgNO3 solution was added to the eluted solution. The AgCl precipitate was separated bycentrifugation and dissolved with 3 M NH4OH. The solution is filtered through 0.20 μm PTFE filter(DISMIC-25HP, Advantec, Tokyo, Japan) and the filtrate was acidified by the addition of 13 M HNO3 toprecipitate AgCl again. After these steps, AgCl precipitate was re-dissolved and re-precipitated in order to
exclude remaining impurity. Finally, AgCl precipitate was washed three times with 0.01 M HNO3 andtwice with 99.5% C2H5OH, and then dried in the oven at 130°C for 3 hours.
As a result, chemical yields of chlorine were 54% and 63% (Table 1), which are lower than previous
method (about 80%). These two samples were measured by the AMS at the Tandem Accelerator Complex,
University of Tsukuba. Against the expectation, there was no clear difference in count rate of 36S
compared to previous method. However, the time required for chemical procedure is much reduced andthe chemical yield is expected to be improved. This new sample preparation scheme is tested further andwill be applied to ice core samples from Dome Fuji in the near future.

40

Fig. 1. A test sample is being passed through an anion-exchange column.
Table 1
Chemical yields of chlorine for test samples
SampleCl carrier added
AgCl recovered
(mg)
(mg)
Blank sample
0.91
2.3
Ice sample
0.92
2.0

Chemical yield of Cl
(%)
63
54

Acknowledgements
We are grateful to Prof. Kunihiko Nishiizumi (Space Sciences Laboratory, University of California,
Berkeley, USA) for his detailed advice on ion exchange column method.
References[1] Y. Nagashima, R. Seki, T. Takahashi, D. Arai, Nucl. Instr. Meth. B 172 (2000) 129.
[2] Y. Nagashima, R. Seki, T. Matsuhiro, T. Takahashi, K. Sasa, K. Sueki, M. Hoshi, S. Fujita, K.
Shizuma, H. Hasai, Nucl. Instr. Meth. B 223–224 (2004) 782.
[3] N.J. Conard, D. Elmore, P.W. Kubik, H.E. Gove, L.E. Tubbs, B.A. Chrunyk, M. Wahlen, Radiocarbon
28 (1986) 556.
[4] S. Jiang, Y. Lin, H. Zhang, Nucl. Instr. Meth. B 223–224 (2004) 318.
[5] S. Vogt and U. Herpers, Fresenius Z. Anal. Chem. 331 (1988) 186.

41

4.6 Estimation of thermal neutron fluences in the concrete of various
accelerator facilities by 36Cl AMS
K. Bessho 1 , H. Matsumura1, T. Miura1, K. Masumoto1, H. Hagura1, Y. Nagashima, R. Seki, T. Takahashi,
K. Sasa, K. Sueki, and Y. Tosaki
At accelerator facilities, concrete components around beam lines are exposed to secondary particles
during machine operation, and various radionuclides are accumulated in the concrete. Concentrations of
the radionuclides induced in the concrete are important for radioactive waste management of accelerator
facilities. Thermal neutron fluence irradiated during machine operation is useful information to estimate
the radioactivities of the nuclides because most of the radionuclides are mainly produced by thermal
neutron-capture reactions. In our previous studies, we have developed a method for AMS of 36Cl in
concrete of accelerator buildings, and demonstrated that the measurements of isotope ratios of 36Cl to 35Cl
(36Cl/35Cl) is suitable for monitoring of the thermal neutron fluences [1,2]. The estimation of neutron
fluences by using radioactivity generally depends on the relation between half-life of radionuclides and theoperational history of accelerator, which is difficult to be exactly clarified. In case of evaluation with theresults of 36Cl AMS, operational histories of accelerators are not indispensable because radioactive decayof 36Cl can be neglected. Consequently, reliable evaluations of neutron fluences without indefinite
assumptions can be attained by 36Cl AMS.
In this year, thermal neutron fluences at various accelerator facilities was determined, and thecharacteristics were discussed in correlations with accelerated energy and particles.
Thermal neutron fluence (Φ) was determined byΦ = (36Cl/35Cl) / σ ,where the cross section for the 35Cl (n, γ)36Cl reaction (σ) was 43.6 barn [3].
Figure 1(a) shows thermal neutron fluences at five kinds of proton accelerators. Acceleration energies
of protons are ranging from 17 MeV to 12 GeV. At proton accelerators, secondary neutrons were induced
by beam-loss at magnets, beam ducts and irradiated targets. Initially-emitted secondary neutrons consist ofvarious energy neutrons ranging from thermal energy to acceleration energy of the particles, and theenergies of secondary neutrons highly depend on the acceleration energies of protons and direction ofneutron emissions. These neutrons had continuously irradiated on the concrete walls, floors and shieldings,
and induced radionuclides in the concrete. Although contribution of high-energy neutrons is higher at theconcrete surface, fast neutrons were partially slowed-down inside concrete, and they finally turns tothermal neutrons. Thermal neutron fluences in Fig.1(a) include penetration of thermal neutrons fromconcrete surface and formation of thermal neutrons inside concrete. As a result, the maxima in thermal
neutron fluences were observed at approximately 5 to 15 cm in the depth, according to the accelerationenergies.
The maximum positions in the thermal neutron fluences shift to deeper positions accompanied by

1

High Energy Accelerator Research Organization
42

increasing acceleration energies in the range of 17 to 65 MeV. Further at high-energy accelerators that
accelerate 400 MeV and 12 GeV protons, secondary neutrons reach deeper into the concrete and thermal
neutrons populate at deep in the concrete compared to those of the several tens of MeV cyclotrons. These
characteristics may reflect the differences in the energy spectra of the secondary neutrons.
At electron accelerator facilities, photo-neutrons populated at beam-loss points and thermal neutrons
were found to be main source for activation of the concrete. Figure 1(b) shows thermal neutron fluences in
the concrete at three kinds of electron accelerator facilities. The 45 MeV electron LINAC at Hokkaido
University also had been utilized to produce pulsed cold-neutrons, and neutrons generated at thesource-target were slowed-down inside the carbon moderator before arriving at the concrete walls. As
contribution of fast neutrons at the concrete surface was less at this facility, the build-up in thermal
neutron fluence was absent. At both of the 220 MeV electron LINAC and the 1.3 GeV electron
synchrotron, build-up effects were observed at depths around 10 cm, as shown in the profiles in Fig. 1(a).
Further, attenuation lengths of thermal neutrons were similar at three kinds of accelerators, and it implied
the similarity in energies of photo-neutrons induced by wide energy-range electrons. Similarity in neutronenergy is contrastive to highly dependence of neutron energy on acceleration energy at proton
accelerators.
Further quantitative analysis on the neutron distribution in the concrete is now in progress, and it will
be valuable for radioactive waste management in decommissioning of accelerator facilities.
References[1] K. Bessho et al., Radiochim. Acta, accepted[2] K. Bessho et al., Nucl. Instr. Meth. B, accepted

15

10

14

10

13

10

12

10

11

2

10

Thermal neutron fluence ( n / cm )2

Thermal neutron fluence ( n / cm )[3] R.B. Firestone, V.S. Shirley ed., Table of Isotopes, 8th ed., Wiley-Interscience, New York 1996.
(a)
(b)

0

20

40
60
Depth (cm)

80

100

10

15

10

14

10

13

10

12

10

11

0

10 20 30 40 50
Depth (cm)Fig. 1 Thermal neutron fluences estimated with 36Cl / 35Cl .
(a) Proton accelerator facilities : 17 MeV (small cyclotron at NMCC) (○), 45 MeV (SF cyclotron at CNS,
the Univ. of Tokyo) (□), 65 MeV (AVF cyclotron at RCNP, Osaka Univ.) (Δ), 400 MeV (RING
cyclotron at RCNP, Osaka University) (●), 12 GeV ( proton synchrotron at KEK) (■).
(b) Electron accelerator facilities : 45 MeV (electron LINAC at Hokkaido Univ.) (○), 220 MeV (electron
LINAC at LNS, Tohoku Univ.) (Δ), 1.3 GeV (electron synchrotron at Tanashi branch, KEK) (●).
43

4.7

Low Z element analysis of the Cr target deposited by HIVIPP method
using a 1.8 MeV He+ beam of Tandetron accelerator

I. Sugai 1 , Y. Takeda1, M. Oyaizu2, H. Kawakami2, K. Sasa, Ishii, and K. Shima

Recently, we have developed a new deposition method of HIVIPP (HIgh energy VIbrational Powder
Plating), which is based on the high energy vibrational motion of powders in the electrostatic field
between parallel electrodes [1-2]. This method has been found to be very useful as a target preparation
technique in both backed and unbacked conditions. This is very simple method. The deposition process
has been performed at room temperature in vacuum. The deposition process could be further simplified if
it could be operated without a vacuum pumping system. The deposition is to operate at higher than one
atmospheric pressure in inert or reactive gases. By this process, new materials could be synthesized whenused the reactive gas. With motivation of this new material systemization, we have tried target deposition
at high pressure of air gas. Elemental compositions of the deposited targets were measured using the 1.0
MV Tandetron accelerator of Tsukuba University.
The experimental apparatus for target deposition is same as that described in the paper [1-2]. The highpressure container is composing of an acryl tube of 20 mm thick. The size of the container is 25 cm indiameter and 35 cm in high. Deposition apparatus is very simple, composing of two parallel metallic disksof 2.5 cm diameter and 0.5 mm thick. The disks (substrate) play as electrodes and hold the backing plate.
The distance between two electrodes is 10 mm, and the glass ring tube with 2.5 cm diameter is inserted
between the disks.
High purity metallic Cr powder with about 100 μm in particle size was used as material to be deposited.
Dried air was used as reactive gas. Two copper plates of 0.3 mm thick were used as backing plate. The
sample of the Cr powder about 50 mg was inserted on the cathode electrode. High pressure air wasinserted into the container up to 3 × 105 Pa. The applied DC high voltage was increased very gradually, in
200 V steps every 5 min. watching the powder behavior. The powders began to vibrate at 2.5 kV. Whenthe voltage was increased to 18 kV, the current charged suddenly from 10 to 70 μA. About 1h was required
at 25 kV to obtain a deposition of 85 μg/cm2 thickness. After the high voltage was switched off, the highpressure gas was ejected to one atmosphere and the electrodes could immediately be removed and handled.
Deposited thicknesses were measured using an electronic ultra microbalance.
The surfaces of the Cr targets deposited onto the both copper plates showed not metallic color but deepnavy blue color. In order to investigate the color change of the Cr deposited target, we performed theelemental analysis of the Cr target by taking the Rutherford Back Scattering (RBS) and Particle Induced

1

Accelerator Research Laboratory, 2Institute of Particle and Nuclear Study, High Energy Accelerator Research Organization44

X-ray Emission (PIXE) spectrum using a 1.8 MeV He+ tandem (Tandetron) accelerator at University ofTsukuba. The measurement was to detect the level of element carbon, nitrogen and oxygen in the deepnavy blue color Cr target, which is considered to be synthesized with air. The light and other heavy
elements of Si, Cr and Cu were detected with a 1.8 MeV He+ beam from the accelerator and particles
scattered at =160° with SSD by RBS and PIXE. For a comparison, we also analyzed a commerciallyavailable (CM) Cr foil (1.0 mg/cm2) and Cr target (~ 120 μg/cm2) made by the same HIVIPP method in
vacuum. Figures 1 and 2 show the obtained spectra of RBS and PIXE. As can be seen, we can clearly see
Cr peak from the 3 targets and the Si peak was also detected except for the CM Cr foil and Cr target madein high pressure. Si peak is from a diffusion pump oil of the HIVIPP deposition in the vacuum apparatus.
However, we can not detect any low Z elements of the 12C, 14N and 16O.
Although the color Cr prepared in 3 × 105 Pa high pressure of air showed deep navy blue color, thedetection of these low Z of the C, N and O elements in this target at first experiment was impossible.
Hence, in next experimental measurement, we will try to detect low Z elements very small amount in thetargets by using an X-ray detector with a super ultra thin polymer.

Fig.1

45

He+ 1.82MeV

Cr (Vac)

SiCr

Cr (CM)

CountsCr (Air)

Cu
Cu(Lα)

ChannelFig.2

Fig.1 and 2

Elemental analysis of Cr targets made by HIVIP method in vacuum and in air high pressureof 3 × 105 Pa and Cr foil of CM. The spectra were obtained by RBS and PIXE with a 1.8 MeV He+ ionsfrom Tandetron accelerator of Tsukuba University.

References[1] I. Sugai, Nucl. Instr. and Meth. A397(1997) 81.
[2] I.Sugai, Nucl. Instr. and Meth.A438(1999) 58.

46

4.8

Imaging of iodinated contrast medium
quasi-monochromatic X-ray emission

using

proton-induced

J. Hasegawa1, J. Kaneko1, Y. Oguri1, and K. Sasa
Until now, many research groups have investigated high contrast angiography using monochromatic
X-rays from synchrotron radiation facilities[1-3]. They obtained high contrast images of iodine contrast
medium in vessels by adjusting the energy of the monochromatic X-rays to the value just above the iodine
K-edge energy. On the other hand, proton-induced X-rays have the potential to be used as
quasi-monochromatic X-ray sources because the characteristic X-rays are dominant in the energy spectra.
In the previous experiments we applied the proton-induced X-rays to high contrast imaging of ruthenium
contrast medium[4]. By choosing the target material that has the KX-ray energy just above the ruthenium
K-edge energy, we successfully obtained high contrast images of the ruthenium contrast medium in asmall phantom. However, because of the limitation of the maximum proton energy, imaging of iodine
contrast medium, which is widely used in clinical practices, was impossible in the previous experiments.
Then we carried out an experiment on high contrast imaging of the iodine contrast medium using ahigher-energy proton beam supplied from 12 UD Pelletron Tandem Accelerator at UTTAC.
Figure 1 shows the experimental setup. We used thick metallic targets of tin (Sn) and lanthanum (La).
A 7-MeV proton beam from the Tandem Accelerator was focused onto the target with a spot size of 1 × 2
mm2. The beam current was 40–80 nA. The X-rays emitted from the target were extracted through a
60-μm-thick, φ30-mm Mylar window. For detection of the X-rays passing through a Lucite phantom, weused an imaging plate with a size of 30 × 50 mm2. An aluminum plate of 100 μm thick was located just in
front of the imaging plate to attenuate LX-rays from the targets. After an exposure of 15–30 minutes, thetransmission image recorded on the imaging plate was read out by a compact digital X-ray imaging system.
A CdTe detector monitored the energy spectra and the irradiation doses of X-rays in parallel with theexposure.
We used two types of Lucite phantoms for the present experiment as illustrated in Fig. 2. One of them
was a rectangular solid, which has seven parallel φ1-mm holes and three parallel φ3-mm holes. The
φ1-mm holes contained iodinated potassium solution with various iodine concentrations: 1000, 500, 200,
100, 50, 10, and 0 mg/cc (water). To imitate bone structures in the body, calcium-hydrogen-phosphate
powder, which was prepared by pounding calcium tablets, was filled in one of the φ3-mm holes. Both theweight percentage of calcium and the mass density of the imitated bone were almost the same as those of

Fig. 1. Experimental setup.

Fig. 2. Schematic illustratios of phantoms.

47

20

bones in the human body. The other two φ3-mm holes

KI aq. 500 mg/cc

Intensity (arb. unit)

10
Bone

5

15

20

-1

Water

Attenuation Coefficient (cm )

15

La K

Sn K

25

30

35

40

45

0
50

Photon Energy (keV)

Fig. 3. X-ray energy spectra and attenuation
coefficient of iodine contrast medium, bone,
and water.

contained an iodinated potassium solution (500 mg/cc) and air,respectively. Another phantom was a 50-mm-long, φ25-mm
cylinder,

aimed

for

computed

tomographyusing

quasi-monochromatic X-rays. This phantom had two φ2-mm
holes containing iodinated potassium solutions with iodine
concentrations of 1000 and 500 mg/cc. An imitated bone
structure (φ3 mm) was also prepared.
Figure 3 shows the energy spectra of Sn and La KX-rays
and the attenuation coefficients of the iodinated potassium
solution with an iodine concentration of 500 mg/cc, bone, andwater. From the La target quasi-monochromatic X-rays with apeak energy of 33.2 keV were obtained, which is just above theiodine K-edge energy. Because of the low energy resolution of
the CdTe detector, the peaks of Kα and Kβ X-ray emissions wereconvolved with each other. The X-ray emission from the Sn
target was also dominated by the characteristic X-rays.
Typical transmission images of the phantom 1 are shown in
Fig. 4. Thanks to the strong absorption of La KX-ray by theiodine contrast medium, the contrast of the image taken with(a) with La target

the La target was much higher than that with the Sn target. The
contrast medium even with an iodine density of 50 mg/cc,
which is much lower than those in clinical practices, could berecognized in the image with the La target. In Fig. 4(a) and (b),shadows of the bone (Ca) and the void (air) structures are stillvisible. By using the dual-energy subtraction method, we could
completely remove the shadows of the bone structures as shownin Fig. 4(c), which indicates that the proton-induced X-rays(b) with Sn target

used in the present experiment were enough monochromatic toperform high-contrast imaging.
References[1] R. Lewis, Phys. Med. Biol., 42 (1997) 1213.
[2] K. Umetani, et al, J. Synchrotron Rad., 5 (1998) 1130.
[3] H. Mori, et al, Radiology, 201 (1996) 173.
[4] S. Iwatani, et al, Sci. and Technol. of Adv. Mat. 5 (2004)
597.

(c) after dual-energy subtraction
Fig. 4. Transmission images of phantom 1with (a) La target, (b) Sn target, and (c) image
after dual-energy subtraction.

1

Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology.

48

4.9

Nanoscale and high aspect ratio patters on SiO2 and TiO2 created with
fast heavy ions

Koichi Awazu1,2, Xiaomin Wang1, Makoto Fujimaki1,3, Tetsuro Komatsubara, Hirotaka Ikeda3, Yoshimichi
Ohki3
1. Center for Applied Near-Field Optics Research, National Institute of Advanced Industrial Science andTechnology (AIST), 1-1-1 Higashi, Tsukuba 305-8562, Japan
2. Department of Engineering Synthesis, School of Engineering, The University of Tokyo, 7-3-1 Hongo,
Bunkyo-ku, Tokyo 113-8656, Japan
3. Department of Electrical Engineering and Bioscience, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku,
Tokyo 169-8555, Japan
A latent track is created by the passage of an atomic particle through dielectric materials. The presenceof tracks is normally reveled after etching the tracks in a suitable liquid. It has been widely examined inmany fields such as nuclear physics and material science because holes with uniform diameter and highaspect ratio (i.e., length much greater than diameter) can be obtained without mask.
It is natural that many researchers would stimulate to think of practical applications of the nuclear tracktechnique. Many fascinating topics have also been appeared. For example, nuclear pore filters widely usedby microbiologist have been manufactured by irradiating a thin polycarbonate sheet with roughly
collimated fission fragments and etching to the desired pore size. Nanowires can serve as field emission
display. Lindeberg and Hjort have developed magneto-resistive sensors of sub-millimeter size and 3D
nanowire circuits. All works were based on etched tracks in polymers such as polycarbonate. It is desired
to create high aspect ratio holes in inorganic materials (e.g., silica glass). Because silica glass is thermallystable, mechanically strong, and one of the least chemically reactive materials, fine filters made from silica
glass would be useful in a much broader range of environments than polycarbonate filters.
The authors have examined structure of the latent track in silica glass. Maximum of length/diameter
ratio of was up to 5 with liquid hydrofluoric acid. Lately, Musket and co-workers have developed vapor
etching technique.[1] Holes with diameter of ~24 to 80nm have been documented with length/diameter
ratio of up to 22. Generally, the shape of the etched hole is not cylindrical, but conical with the largest
diameter being near the surface. This is a consequence of the etching rate in the latent tracks VT being
comparable to the general etching rate VG in the track-free regions. A near cylindrical hole results when the
etching rate in the latent track is very high compared to the general attack. An typical example of suchmaterial is titanium dioxide of rutile single crystal. The goal of our work is to create uniform nano size
holes with high ratio of length/diameter of silica and titania in order to use as nuclear pore filters toseparate molecular-sized materials. Especially, titania with nuclear pore would be useful as photo-catalysis
filters.
Figure 1 shows high resolution transmission electron micrograph of a sample irradiated with 50 MeV
Br8+ (a-1) followed by 20% hydrofluoric acid etching for 10 s (a-2). Hereafter, 1 and 2 in ([letter]-1 and[letter]-2) denote before and after etching, respectively. (b) 115 MeV Br11+, (c) 120 MeV I11+, (d) 150 MeV

49

Au14+. All scale bars indicate 2nm. In Figure 1, the first-order feature is that damaged zones of milky color
assigned to amorphous and stressed lattice around amorphous part can be seen. The densities of rutile andamorphous TiO2 have been reported as being 4.25 g/cm3 and 2.4–3.4 g/cm3, respectively.[2] It is possiblethat the transformation from the rutile phase to the amorphous phase caused volume expansion which led
to lattice stress. In fact, swelling of the damaged zone deduced from volume expansion was observed in
AFM images.

Fig.1.TEM observation of TiO2 rutile single oxide before and after acid etching

References[1] R.G.Musket, J.M.Yoshiyama, R.J.Contolini, J.D.Porter, J.Appl.Phys., 91 (2002) 5760.
[2] D. Mergel, Thin Solid Films, 397 (2001) 216.

50

4.10

New detection system of ERCS hydrogen analysis

T. Komatsubara, K. Sasa, M. Kurosawa, S. Ishii, Y. Yamato, T. Kawamata, K. Iwamura, H. Okaguchi,
M. Furukawa
In our micro beam facility with 20 MeV proton ions, basic studies of hydrogen analysis using elastic
recoil coincidence spectrometry (ERCS) are in progress. Developments of the detection system and ananalysis method have been carried out to improve the accuracy of the hydrogen determination.
1) New detector system
Asymmetric detector apertures have been introduced for the sake of better stability of the coincidence
yield. Diameter of the right aperture is 8 mm while the left one is 12 mm. Measured yields by changing z
position are shown in Fig. 1. In this figure open squares show for the asymmetric window. The yields arestabilized using the asymmetric collimater system.
A detector folding table was newly designed so as to adjust detector position using six screws for
xyz-three-directions as shown in Fig. 2. Alignment of the detectors was performed within several tens
micro meters.
2) New analysis method
Fig. 3(a) shows a 2 dimensional spectrum using a stack target consisting of five Mylar films and fourglass plates. The measured five lines correspond to the hydrogen in Mylar films. These lines appear as
bended curves, since the stopping energy depends on the scattering angle. In our study of the spectra, thecurves were found to be parabola;
X = E1 − E2 ,Y = E1 + E2 − Esum ,Y = −αX 2 .

(1)

The parameter α was found to be a simple function of Esum as follows where two parameters k0 = 0.114
MeV−1 and k0 = −0.006 MeV−2 are introduced;
α = k0 + k1 · Esum .

(2)

For a measured point (E1 , E2 ) corresponding Esum for the symmetry scattering can be calculated as
Esum =

E1 + E2 + k0 · (E1 − E2 )2.
1 − k1 · (E1 − E2 )2(3)

The position (E1 , E2 ) in the 2-dimensional spectrum is modified to (E10 , E20 ) as1
1
E10 = E1 + (Esum − E1 − E2 ),E20 = E2 + (Esum − E1 − E2 ).
(4)
2
2
Using these formula the 2-dimensional plot is modified as Fig. 3(b). The bending curves are corrected tostraight lines.

513) Depth resolution
For the hydrogen depth profiling, depth resolution is one of the important parameters. Detection
resolutions were measured by changing bombarding energy of proton beam as shown in Table 1. For theirradiation targets, thin layers of Formvar were prepared as coating on both surfaces of a 10 µm anhydrous
glass plate. Thickness of the Formvar was measured to be 13 ± 3 µm/cm2 .
As a result of the experiments, it has been turned out that the depth resolution strongly depends on the
beam energy. When the beam energy decreases, the resolution becomes small. However, total thicknessof the irradiation target should be thinner for the low energy measurement. Our result is consistent to theprevious report[1].
4) Calibration
In order to determine an accuracy and a precision of the hydrogen analysis, calibration measurements
were carried out using Mylar, Kapton, Polyethylene, Ti(H) and PL-01. The PL-01 film is a kind of
Polyimide which was provided by NTT Advanced Technology Corporation.
Hydorgen weight densities determined using ERCS are compared with those by CHN elemental analyzer (Perkin-Elmer 2400). The certificated value by NIST[2] is also compared for Ti(H). As a result of
the measurement systematic error of ERCS analysis was evaluated as 3 %. When Mylar films are used as
supporting films and as standard material, deviation of hydrogen content in one Mylar film is dominant
to determine the precision of the analysis. The standard deviation of hydrogen content in one Mylar film
was measured to be 3 %. Total deviation of the hydrogen analysis using ERCS can be determine less than
5 %.
Acknowledgement
NTT Advanced Technology Corporation is deeply acknowledged for their free samples of Polyimide
films.
Reference[1] Wegden, et al., NIM B231 (2005) 524-529[2] National Institute of Standards & Technology, Certificate of Analysis, Standard Reference Material
352c, Hydrogen in Unalloyed Titanium, Hydrogen Concenration: 49.0 ± 0.9 µg/g

Table 1 Measured results of ERCS resolutions. The Mylar target is a self-support
film of 2.5 µm thickness. The Formvar target is coating on 10 µm anhydrous glass.
Beam energy
[MeV]
4
6
12
15
20

FWHM
[keV]
54
70
120
140
170

52

FWHM
[µm]
0.85
1.5
4.4
6.0
9.2

targetFormvarFormvar
Mylar
Mylar
Mylar

Table 2 Calibration of hydrogen contents.
Material(thickness)
Mylar(2.5µm)Kapton(7.5µm)Polyethylene(30µm)
FL-01(2.5µm)Ti(H)(113µm)surface density[mg/cm2 ](relative error)
0.348 ± 0.006(1.7%)
1.085 ± 0.027(2.5%)
2.43 ± 0.06
(2.5%)
3.610 ± 0.075(2.1%)
51.5 ± 2.6(5.0%)

reference of hydrogen[wt.%](relative error)
4.49 ± 0.06
(1.3%)
2.88 ± 0.03
(1.0%)
14.0 ± 0.2(1.4%)
1.81 ± 0.05
(2.7%)
0.00490 ± 0.00009(1.8%)ERCS analysis[wt.%](relative error)
4.49 (reference)(3.7%)
2.84 ± 0.10
(3.3%)
13.7 ± 0.3(2.0%)
1.80 ± 0.05
(2.7%)
0.0049 ± 0.0001(2.0%)

+

+

+
+

+

Relative yieldasymmetry

+

+

100

50

symmetry+
slit size : 8 mm

0
−2000

−1000

0

1000

+

+

+

2000

z displacement [micro m]

Fig. 1. Coincidence yields as functions of z position. Open squares show for the asymmetric window system, while closed
circles for the symmetric window. Calculations for the symmetric cases arealso shown by solid and dashed lines.

Fig. 2. Newly designed detector table. Adjusting bolts are shown by gray color for
xyz-three-directions.

20

Multi layer sample
quartz(a)(b)
modified spectrum

Proton energy [MeV]

mylar

beam

15
12345

10

4
3

5

5

2
1

1

5
4
3
2

0
0

5

10

15

0

Proton energy [MeV]

5

10

15

20

Proton energy [MeV]Fig. 3. ERCS 2-dimensional spectra. 3(a) shows raw data, and 3(b) is modified spectrum using the method
described in text.

53

5.
TECHNICAL REPORT5.1

New data aquisition system using CC/7700

H. Kimura, T. Komatsubara
A PC based data acquisition system has been developed by using TOYO CC/7700 parallel crate
controller, where FreeBSD 6.0-RELEASE is employed as the host operating system.
Software of this system consists of device driver, main process and GUI process. Main feature of thedevice driver is handing interrupt generated by CC7700 and executes CAMAC command list that preloaded
by user demand. User can upload a CAMAC command list for individual LAMs. If the list contains
CAMAC read functions, data are buffered in the driver, and transferred to the main process.
The main process controls the system. There are no preferred acquisition routines in this system. User
should write their callback routines to initialize CAMAC modules which include start and stop functions
and event processor. At startup time, the main process compiles user routines and links it to itself. User may
write routines in two languages, C and CAMAC. For example, Fig. 1 shows user code to read and process
two channels of data from CAMAC ADC with self trigger. After loading these codes the main process
executes "init:" section in the CAMAC file, then executes "init()" routine in the C file. The "LAM1:" sectionin the CAMAC file is the interrupt routine to read event data. That code will compiled and uploaded to thedriver.
/* test1.camac */#define ADC N1
init: /* reset ADC */ADC,F9,A0/* test1.c */#include "daqlib.h"
int ch0,ch1;
int init () {/* allocate histograms */ch0 = hist_new1("ch0",2048);
ch1 = hist_new1("ch1",2048);
return OK;}/* process event data */int event (int data[], int n){hist_add1(ch0,data[0]&0xffff);
hist_add1(ch1,data[1]&0xffff);
return OK;}

run:/* enable LAM */ADC,F26,A0

stop:/* disable LAM */ADC,F24,A0

LAM1:/* read data then reset */ADC,F0,A0
ADC,F0,A1
ADC,F9,A0

Fig. 1. User code for CAMAC ADC
The GUI process is the user interface of this system, as shows in Fig. 2. There are four user defined
buttons (button1,button2,button3,button4) and four input boxes (shown as 100,500,100,500). Eachelements connected to user callback routines. For example, if the button labeled by "button1" is pressed, themain process executes the "button1:" section of a CAMAC file and "button1()" routine in a C file.
55

Fig.2. The GUI of the system
CC7700 is a cheap but not a fast controller. One CAMAC read/write function needs about 6 micro
seconds and a control function needs about 4 micro seconds. In order to evaluate the dead time of the dataacquisition, three methods have been developed as numeric calculation, timer counter and trigger counter.

56

6.
RELATED TOPICS

6.1 Highly-concentrative immobilization of an enzyme only on a small
sensitive area and its effect on sensor performance
M. Hashimoto, N. Sakamoto and H. Suzuki
1. INTRODUCTION
Over the last decade, there has been a marked progress in the μTAS or Lab-on-a-Chip technology.
Among various devices, electrochemical microsystems are very promising in their application to micro
health-care systems. We have been focusing our attention to highly sensitive, efficient detection of a verysmall amount of analyte on the basis of amperometric detection in a micro flow channel. Along withstructural and conditional parameters of the system [1], improvement in the performance of the sensor
itself is a critical issue, which was a major theme of this study. We have already developed a method toconcentrate materials in a droplet of a solution only on a sensitive area using a super-hydrophobic surface[2]. In this study, we used this technique to form a highly active enzyme layer only on the sensitive area.
The details of the technique and the performance of sensors fabricated by this method in a solution in a
beaker or a micro flow channel will be reported.
2. EXPERIMENTAL
Fabrication of the device
Electrodes were formed on a glass substrate. For batch-style measurements, only a working electrodewas prepared, and a commercial reference electrode and a platinum auxiliary electrode were used.
In immobilizing an enzyme by evaporative concentration, a dry-film photoresist layer was additionallyformed on the polyimide layer. A super-hydrophobic layer was formed in an area other than the sensitive
area by depositing polytetrafluoroethylene (PTFE) beads (diameter: 1 μm). The sensitive area wasprotected with a PDMS cylinder. In depositing the PTFE beads, they were floated on distilled-deionizedwater. The thin layer of beads was carefully transferred to the surface of the chip. After drying at room
temperature, the PDMS cylinder was removed. As a result, a super-hydrophobic layer was formed in thearea that surrounded the sensitive area. To immobilize the enzyme, a solution containing glucose oxidase,bovine serum albumin, and glutaraldehyde was placed on the sensitive area. The solution was repelledfrom the surrounding super-hydrophobic area (Fig. 1(a)). The enzyme solution was then concentrated byevaporation. The droplet finally shrank to the sensitive area and an enzyme-immobilized layer was formed
only on the sensitive area (Fig. 1(b)). After the immobilization of the enzyme, the dry-film photoresist was
peeled off along with the PTFE beads (Fig. 1(c)).
Measurement procedure
For batch-style measurements, an aliquot of a 1 mM glucose standard solution was injected into a 0.1 M
phosphate buffer solution containing 0.1 M KCl (pH 7.4). The solution was stirred for 10 s and themeasurements were taken in a quiescent solution. In conducting the experiments using the micro flow
channel a standard solution was injected by using a micro syringe pump at a fixed flow rate. The potentialof the working electrode was poised at + 0.7 V (vs. Ag/AgCl).

57

3. RESULTS
Fig. 2 compares the calibration plots obtained using sensors fabricated by the novel method and theconventional method. The amount of the enzyme was the same for both cases. When the enzyme wasimmobilized by the conventional method, the behavior of the output current was basically the same as thatreported in numerous papers. The calibration plot was linear up to approximately 1 mM and thedependence became weaker at higher concentrations. When the enzyme was immobilized by the novel
method, a significant increase in the output current was observed and the linear region extended to higher
concentrations. This suggests that the diffusion of glucose and oxygen (particularly the latter) was
enhanced.
The effect of the size of the electrode area was examined by changing the diameter of the electrodebetween 0.3 and 1 mm. Although the current increased as the size of the electrode area increased, thecurrent density was higher with smaller electrodes.
Droplet(a)3

PTFE beads

Film resist

Working electrode

Current (μ A)

2.5

Glass substrate

(b)

2
1.5
1
0.5
0

(c)

0

2
4
6
8
10
Glucose concentration (mM)

Fig. 1. Evaporative concentration using a superFigure 2. Comparison between the novel-hydrophobic surface. (a): Droplet placed on amethodhydrophilicaWorking electrode diameter: 1 mm. Enzyme

super-hydrophobic layer. (b): Droplet shrunk after

was immobilized by the novel method (■)

evaporation. (c): Enzyme-immobilized layer after theand the conventional method (○).

sensitivearea

surrounded

by

and

the

conventional

method.

thick-film photoresist was peeled off along with thePTFE beads.
References[1] M. Hashimoto, S. Upadhyay, H. Suzuki, “Dependence of the response of an amperometric biosensor
formed in a micro flow channel on structural and conditional parameters”, Biosensors andBioelectronics, in press.
[2] I. Yanagimachi, N. Nashida, K. Iwasa, H. Suzuki, “Enhancement of the sensitivity of electrochemical
stripping analysis by evaporative concentration using a super-hydrophobic surface”, Science andTechnology of Advanced Materials, vol. 6, pp. 671-677, 2005.

58

7. LIST OF PUBLICATIONS
The publications listed here are those released in the fiscal year 2005 by all the workers listed on§11.

7.1 Journals
NUCLEAR PHYSICS
1. C. Wu, Y.Yamaguchi, A.Ozawa, I.Tanihata, D.Jiang, H.Hua, T.Zheng, Z.Li and Y.Ye, Neutron
removal reactions of 17 C, J. Phys. G: Nucl. Phys. 31 39-47 (2005).
2. Y.L.Ye, D.Y.Pang, D.X.Jiang, T.Zheng, Q.J.Wang, Z.H.Li, X.Q.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 6 He on 9 Be at 25 MeV/nucleon, Phys. Rev. C 71, 014604 (2005).
3. K. Kimura, T. Izumikawa, R. Koyama, T. Ohnishi, T. Ohtsubo, A.Ozawa, W. Shinozaki, T.
Suzuki, M. Takahashi, I. Tanihata, T. Yamaguchi, Y. Yamaguchi, High-rate particle identification of high-energy heavy ions using a tilted electrode gas ionization chamber, Nucl. Instr. andMeth. A 538, 608-614 (2005).
4. R.Kanungo, Z.Elekes, H.Baba, Zs.Dombradi, Zs.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, K.Yoshida, Excited states in neutron rich boron isotopes, Phys. Let. B 608 206-214(2005).
5. Z.Elekes, Zs.Dombradi, R.Kanungo, H.Baba, Zs.Fulop, J.Gibelin, A.Horvath, E.Ideguchi, Y.Ichikawa,N.Iwasa, H.Iwasaki, S.Kanno, 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, K.Yoshida, Low-lying excited states in 17,19 C, Phys. Let. B 614
174-180 (2005).
6. R.Kanungo, Z.Elekes, H.Baba, Zs.Dombradi, Zs.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, K.Yoshida, Search for an isomeric state in 19 C, Nucl. Phys. A 757 315-328 (2005).
7. Zs.Dombradi, Z.Elekes, R.Kanungo, H.Baba, Zs.Fulop, J.Gibelin, A.Horvath, E.Ideguchi, Y.Ichikawa,N.Iwasa, H.Iwasaki, S.Kanno, 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, K.Yoshida, Decoupling of valence neutrons from the core in 17 B,
Phys. Let. B 621 81-88 (2005).

59

8. T. Hashimoto, H. Ishiyama, T. Ishikawa, T. Kawamura, K. Nakai, Y.X. Watanabe, H. Miyatake,
M.H. Tanaka, Y. Fuchi, N. Yoshikawa, S.C. Jeong, I. Katayama, T. Nomura, T. Furukawa, S.
Mitsuoka, K. Nishio, M. Matsuda, H. Ikezoe, T. Fukuda, S.K. Das, P.K. Saha, Y. Mizoi, T.
Komatsubara, M. Yamaguchi, Y. Tagishi, Gated multiple-sampling and tracking proportional
chamber new detector system for nuclear astrophysical study with radioactive nuclear beams,
Nucl. Instr. and Meth. A 556 (1): pp.339-349, Jan 1 (2006).
9. E. Ideguchi, M. Niikura, C. Ishida, T. Fukuchi, H. Baba, N. Hokoiwa, H. Iwasaki, T. Koike, T.
Komatsubara, T. Kubo, M. Kurokawa, S. Michimasa, K. Miyakawa, K. Morimoto, T. Ohnishi,
S. Ota, A. Ozawa, S. Shimoura, T. Suda, M. Tarnaki, I. Tanihata, Y. Wakabayashi, K. Yoshida,
B. Cederwal, Study of high-spin states in the Ca-48 region by using secondary fusion reactions,Eur. Phys. J. A 25, pp.429-430, (2005).
10. S-Y Wang, T Komatsubara, Y-J Ma, K Furuno, Y-H Zhang, Y-Z Liu, T Hayakawa, J Mukai, Y
Iwata, T Morikawa, G B Hagemann, G Sletten, J Nyberg, D Jerrestam, H J Jensen, J Espino, J
Gascon, N Gjorup, B Cederwall, P O Tjom, Band Structure in 123 I, J. Phys. G: Nucl. Phys. 32
pp.283-294, (2006).
11. T.Nagatomo, A. Ozawa, et al, Magnetic moment of extremely proton-rich nucleus 23 Al, J.
Phys.: Conf. Ser. 20 pp.173-174 (2005).

ATOMIC AND SOLID STATE PHYSICS, AND CLUSTER SCIENCE

12. Olga V. Boltalina, Alexey V. Streletskii, Ilya N. Ioffe, Preben Hvelplund, Bo Liu, Steen Broendsted Nielsen, and Shigeo Tomita, “Formation of long-lived fluorofullerene trianions in collisions with Na”, J. Chem. Phys. 122, 021102(1-3), (2005).
13. B. Concina, S. Tomita, J.U. Andersen, and P. Hvelplund, “Delayed ionization of C70 ”, Eur.
Phys. J. 34, pp.191-194 (2005).
14. H. Kudo, Iwazaki, Wakamatsu, S. Tomita, “Resonant Coherent Excitation of C5+ in Si Observed with Backward Electron Spectroscopy”, Nucl. Instr. and Meth. B 229, 227-231 (2005).
15. S. Tomita, J.U. Andersen, E. Bonderup, P. Hvelplund, B. Liu, S. Broen dsted Nielsen, U.V.
Pedersen, J. Rangama, K. Hansen, O. Echt, “Dynamic Jahn-Teller Effects in Isolated C-60
studied by Near-Infrared Spectroscopy in a Storage Ring”, Phys. Rev. Lett. 94, 053002 (2005).
16. B. Manil, L. Maunoury, J. Jensen, H. Cederquist, H.T. Schmidt, H. Zet tergren, P. Hvelplund,S. Tomita, B.A. Huber, “Fragmentation of charged fullerene dimers: Kinetic energy release”,
Nucl. Instr. and Meth. B 235, 419-424 (2005).
17. L. Maunoury, B. Manil, J. Rangama, H. Lebius, B.A. Huber, J.Y. Pacque t, R. Leroy, U.V.
Pedersen, P. Hvelplund, J. Jensen, S. Tomita, H. Ze ttergren H.T. Schmidt, H. Cederquist, F.

60

Gustavo, “Ion beams of carbon clusters and multiply charged fullerenes produced with electron
cyclotron resonance ion sources”, Rev. Sci. Instr. 76, 053304(1-8) (2005).
18. T. Kaneko, H. Kudo, S. Tomita, and R. Uchiyama, “Secondary electron emission from graphite
induced by MeV/atom carbon cluster impacts”, J. Phys. Soc. Jpn., 75 034717 (2006).
19. Masashige Onoda, Shintaro Miyasaka, Tomohiro Mutoh and Katsuhiro Nichogi, Li local environments and the dynamics in the Li1+x V3 O8 insertion electrode, J. Phys.: Condens. Matter,17(26), 4057-4071 (2005).
20. Masashige Onoda and Junichi Hasegawa, The spin-singlet states in the double trellis-layer
bronzes Na0.56 V2 O5 with a uniform valence and Sr0.5 V2 O5 with a valence order, J. Phys.:
Condens. Matter, 18(7), 2109-2123 (2006).
21. Masashige Onoda and Mitsuko Onoda, Multifunctional composite crystal Cux V4 O11 (x ≈ 2.2),
Phys. Rev. B 73, 104108 (2006).
22. Masashige Onoda, The science of vanadium oxide systems, CERAMICS JAPAN 41(3), 167172 (2006)
23. N. Yagi, A. Ueki, H. Mizubayashi and H. Tanimoto, ”Anelasticity in FCC Nanocrystalline
Metals”, Journal of Metastable and Nanocrystalline Materials, 24-25, 503-506, (2005).
24. H. Tanimoto, S. Sakai and H. Mizubayashi, ”Giant Irradiation Effects in FCC Nanocrystalline
Metals”, Journal of Metastable and Nanocrystalline Materials, 24-25, 597-600, (2005).

ION BEAM ANALYSIS AND APPLICATION

25. Yasuo Nagashima, Riki Seki, Takeshi Matsuhiro, Tsutomu Takahashi, Kimikazu Sasa, Toshihide Usui, Keisuke Sueki, 36 Cl Measurements in Japan, ”Reassessment of the Atomic Bomb
Radiation Dosimetry for Hiroshima and Nagasaki-Dosimetry System 2002”, Report of the
Joint US-Japan Working Group, Chapter 8, Part F, pp.555-560, The Radiation Effects Research
Foundation, (2005).
26. Kimikazu Sasa, Yasuo Nagashima, Tsutomu Takahashi, Riki Seki, Yuki Tosaki, Keisuke Sueki,
Kotaro Bessho, Hiroshi Matsumura, Taichi Miura, Jiang Shan and Ming He, Status and futureplans of the Tsukuba AMS system, 1st East Asian Symposium on Accelerator Mass Spectrometry 26-27, January 2006, University of Tsukuba, Proceedings of the 1st East Asian Symposiumon Accelerator Mass Spectrometry, UTTAC-74 (2006) 69-80.
27. Ming He, Shan Jiang, Y. Nagashima, Yaoyun Yang, T. Takahashi, Kexin Liu, K. Sasa, Kejun
Dong, Shayong Wu, T. Matsuhiro, H. Tosaki, Xiaotang Ren, R. Seki, K. Sueki, Measurementof the cross-section of 14 N(16 O,α)26 Al with AMS, Nucl. Instr. and Meth. B, 240 612-616(2005).

6128. K. Awazu, M. Fujimaki, Y. Ohki, T. Komatsubara, Photonic crystals of titanium dioxide fabricated by swift heavy ions, Rad. Meas. 40 (2-6): pp.722-729 Sp. Iss. SI, NOV (2005).
29. M. Kurosawa, K. Miyakawa, T. Komatsubara, K. Sato, K. Sasa, S. Ishii, Y. Yamato, Y. Kobayashi,
R. Anma, Hydrogen analysis of melt inclusions in chromian-diopside megacrysts from basaly
and basaltic andesite dykes intruded in a collision zone of the Izu-Bonin arc, Gekkan Chikyu,
Vol.27, No.7, pp.519-524, (2005).
30. T. Komatsubara, K. Sasa, S. Ishii, Y. Yamato, K. Miyakawa, K. Satou, M. Kurosawa, Hydrogen
analysis for geoscience by using nuclear microbeam, Proc. of The 5th Italy-Japan Symposium,
Recent Achievements and Perspectives in Nuclear Physics, pp.429-437, (2005).
31. T. Komatsubara, K. Sasa, H. Ohshima, H. Kimura, Y. Tajima, T. Takahashi, S. Ishii, Y. Yamato,
M. Kurosawa, K. Furuno, Hydrogen Content in Granite, ”Reassessment of the Atomic Bomb
Radiation Dosimetry for Hiroshima and Nagasaki-Dosimetry System 2002”, Report of the Joint
US-Japan Working Group, Chapter 10, Part E, pp.750-754, Radiation Effects Research Foundation, (2005).

7.2 International conferences
1. A. Ozawa, (Invited Talk), Nuclear matter radii determined by interaction cross sections, Workshop on Physics with Ultra Slow Antiproton Beams, 2005, 3/14-16, Wako, Japan.
2. A. Ozawa, (Invited Talk), Recent experiments of interaction and reaction cross sections andthe related results, Hawaii 2005 second joint meeting of the nuclear physics division of the APS
and JPS, 2005, 9/18-22, Maui, Hawaii, USA.
3. A. Ozawa, Interaction cross section / mass measurement, Workshop on nuclear physics collaboration between Germany and Japan, 2005, 12/16-17, RIKEN, Wako, Japan.
4. Yasuo Nagashima, Kimikazu Sasa, Riki Seki, Tsutomu Takahashi, Takeshi Matsuhiro, Keisuke
Sueki, Yuki Tosaki, A 129I-AMS by a 97Mo16O molecular pilot beam method, The 10th
International Conference on Accelerator Mass Spectrometry (2005), Berkeley, UCLA.
5. Riki Seki, Takeshi Matsuhiro, Yasuo Nagashima, Tsutomu Takahashi, Kimikazu Sasa, Keisuke
Sueki, Yuki Tosaki, Kotaro Bessho, Hiroshi Matsumura, Taichi Miura, Isotopic ratios of 36 Cl/Cl
in Japanese surface soil, The 10th International Conference on Accelerator Mass Spectrometry,(2005), Berkeley, UCLA.
6. Kotaro Bessho, Hiroshi Matsumura, Taichi Miura, Kazuyoshi Masumoto, Qingbin Wang, Hiroyuki Hagura, Yasuo Nagashima, Riki Seki, Tsutomu Takahashi, Kimikazu Sasa, Keisuke
Sueki, Takeshi Matsuhiro, Yuki Tosaki, Estimation of thermal neutron fluences in various accelerator facilities by using 36 Cl AMS, The 10th International Conference on Accelerator Mass
Spectrometry, (2005), Berkeley, UCLA.

62

7. Yuki Tosaki, Norio Tase, Yasuo Nagashima, Riki Seki, Tsutomu Takahashi, Kimikazu Sasa,
Keisuke Sueki, Takeshi Matsuhiro, Taichi Miura, Kotaro Bessho, Hiroshi Matsumura, Ming
He, Gudrun Massmann, Application of 36 Cl as a dating tool for modern groundwater, The 10th
International Conference on Accelerator Mass Spectrometry (2005), Berkeley, UCLA.
8. Kimikazu Sasa, Yasuo Nagashima, Tsutomu Takahashi, Riki Seki, Yuki Tosaki, Keisuke Sueki,
Taichi Miura, Kotaro Bessho, Hiroshi Matsumura, Ming He, 26 Al and 36 Cl AMS system at the
University of Tsukuba: A progress report, The 10th International Conference on Accelerator
Mass Spectrometry (2005), Berkeley, UCLA.
9. T. Nagatomo, ”Magnetic Moment of Extremely Proton-rich Nucleus 23 Al”, 2nd Joint Meetingof DNP-APS and JPS, Sep. 18-22, 2005, Ritz-Carlton, Kapalua Maui, Hawaii, USA.

63

8. THESES
M. Sc. Theses
Yuji Ito

Study of 118 Sn(d,p) reaction below Coulomb barrier

Kentaro Miki

Measurement of asymmetric emission of direct photon
in RICH heavy-ion experiment

Takuma Yasuno

Development of tilted electrode gas ionization chamber
for a measurement of an energy loss of an unstable nucleus

9. SEMINARS
Date
2005

Title and Speaker

Apr.

20

Development of the SPring-8 linac control system
for stable continuous injection
T. Masuda (JASRI)

Jun

1Studies of resonance states in proton-rich nuclei
with low-energy RI beams
A. Saito (CNS, The Univ. of Tokyo)

Jan.

18

Study of 118 Sn(d,p) reaction below Coulomb barrier
Y. Ito (Univ. of Tsukuba)

Jan.

25

Measurement of asymmetric emission of direct photon
in RICH heavy-ion experiment
K. Miki (Univ. of Tsukuba)

2006

Development of tilted electrode gas ionization chamber
for a discrimination of the secondary ion beam
T. Yasuno (Univ. of Tsukuba)
Feb.

1

Simulation of performance for a Multigap Resistive Plate Chamber
M. Narisawa (Univ. of Tsukuba)

Feb.

9

Nucleon-nucleon momentum correlation function in light nuclei
induced reactions
Yu-Gang Ma (Shanghai Institute of Applied Physics)

Mar.

17

Dosimetry study for the residents near Semipalatinsk Nuclear
Test Site and proposal of 129 I measurement
S. Endo (Hiroshima University)6410. SYMPOSIA
Mass Measurements in the Isochronous Rare-RI Ring and Nucleosynthesis
29 September, 2005
Room C305, Tandem Accelerator Complex,
Research Facility Center for Science and Technology, University of Tsukuba

1. Opening remark : A.Ozawa (Univ. of Tsukuba)
2. Physics opportunities with the RI Beam Factory at RIKEN : H.Sakurai (RIKEN)
3. Mass measurements in the isochronous rare-RI ring : A.Ozawa (Univ. of Tsukuba)
4. Isochronous ring and its computer simulation : I.Arai (Univ. of Tsukuba)
5. Injection line to the isochronous rare-RI ring : H.Ota (Univ. of Tsukuba)
6. Discussion of injection scheme and kicker magnet design for isochronous ring : Y.Yamagchi(RIKEN)
7. Extraction of fractions of the resonant component from analyzing powers in 6 Li(d,α)4 He and6 Li(d,p)7 Li reactions at very low incident energies : M.Yamagchi (RIKEN)
8. Atomic mass formula and r-process nucleosynthesis : H.Koura (JAERI)
9. Present status of mass measurements of unstable nuclei by a multi-reflection time-of-flight mass
spectrometer : Y.Ishida (RIKEN)
10. Mass measurements with a CIME cyclotron at GANIL : T.Ootsubo (Univ. of Nuiigata)
11. Studies of supernovae nucleosyntheis at UTTAC : T.Hayakawa (JAERI)
12. Studies of resonance states in proton-rich nuclei using low-energy RI beams : A.Saito (CNS,The Univ. of Tokyo)
13. Particle discrimination using pulse shape analysis in Si detector : M.Kurokawa (RIKEN)
14. Closing remark : I.Arai (Univ. of Tsukuba)

1st East Asian Symposium on Accelerator Mass Spectrometry, EAAMS-1
26-27 January, 2006
Room No. B0110, Laboratory of Advanced Research B
University of Tsukuba

1. Opening 1 : Sadao Aoki (Univ. of Tsukuba)
2. Opening 2 : Mineo Imamura (National Museum of Japanese History)65

3. Introduction of a compact AMS system for earth science in KIGAM : Wan Hong (Korea Institute of Geoscience and Mineral Resources (KIGAM))
4. Status and future plans of NIES-TERRA : Minoru Yoneda (NIES)
5. AMS facility in Xian and its application to paleoenvironment and paleoclimate study : Weijian
Zhou (Chinese Academy of Sciences)
6. Current status of the NSF-Arizona AMS Laboratory : Kyeong J. Kim (The University of Arizona)
7. Current status of the compact 14C AMS system at Paleo Labo Co., Ltd. : Etsuko Niu (Paleo
Labo Co., Ltd.,)
8. Particle Identification Techniques in AMS Measurement : Jiang Shan (China Institute of Atomic
Energy)9. Dating Upper Paleolithic sites in Korea : Jong Chan Kim (Seoul National University)
10. The project of the ”Yayoi Chronology” and user-facility relationships CSR-program collaboration ”The Origin of the Farming in the Yayoi Period and East Asia” : Mineo Imamura (National
Museum of Japanese History)
11. PKUAMS and the Project of Xia-Shang-Zhou Chro Chronology: Progress and Some Results :Guo Zhiyu (Peking University)
12. High precision 14 C measurements with AMS and applications in archeology and geology at
Nagoya University : Toshio Nakamura (Nagoya University)
13. An ideal AMS facility - a view from AMS user : Kunihiko Nishiizumi (University of California,
Berkeley)
14. Status and future plans of the Tsukuba AMS system : Kimikazu Sasa (Univ. of Tsukuba)
15. 99 Tc measurement with AMS at CIAE : He Ming (China Institute of Atomic Energy)
16. Status of JAEA Mutsu Tandetron AMS Facilities : Hikaru Amano (Japan Atomic Energy
Agency)17. Discussion & Closing of EAAMS-1 : Mineo Imamura and Koichi Kobayashi

The 8th Japanese Symposium on Accelerator Mass Spectrometry, JAMS-8
27-28 January, 2006
Room No. B0110, Laboratory of Advanced Research B
University of Tsukuba

1. Current status of AMS at MALT, The University of Tokyo, in 2005 : K.Kato (The Univ. ofTokyo)
2. High-precision radiocarbon measurements of tree-ring-dated wood from Japan:685BC-193BC: H.Ozaki (National Museum of Japanese History)
3. Study of archaeological site formation process restoration using AMS radiocarbon dating :S.Muramoto (Graduate University for Advance Studies)66

4. Radiocarbon dating of lipids in Lake Baikal surface sediments : T.Watanabe (Nagoya Univ.)
5. Concentrations of 7 Be, 10 Be in the atmosphere at Tokyo and Hachijo-Island during the period
2002 to 2003 : T.Yamagata (Nihon Univ)
6. Distribution of 7 Be and 10 Be in Antarctic Ocean : E.Taguma (Nihon Univ.)
7. The 10 Be flux record in marine sediment in the Western North Pacific : T.Yoshida (Nihon Univ.)
8. Radiocarbon dating of carbonaceous samples excavated at the Muramatsu-Shirane site, Ibaragi
Prefecture, Japan : H.Oda (Nagoya Univ.)
9. Calendar age of the Early Yayoi Period in the South-west Kanto: Estimates from the remains
at the Naka-yashiki site, Ooi-machi, Kanagawa : Y.Sasaki (Paleo Labo Co., Ltd.)
10. Calendar age of the late Middle to the early Late Jomon pottery in Fukushima prefecture :S.Itoh (Paleo Labo Co., Ltd.)
11. Carbon and nitrogen isotopic fractionation in bone collagen during chemical treatment : M.Minami(Nagoya Univ.)
12. Dating of groundwater : N.Tase (Univ. of Tsukuba)
13. Application of bomb-produced 36 Cl in groundwater dating : Y.Tosaki (Univ. of Tsukuba)
14. AMS of 36Cl induced in the concrete of accelerator facilities -Thermal neutron fluences in theconcrete of various accelerator facilities- : K.Bessho (KEK)
15. Application of microscale AMS 14 C analyses to micro organic pollutants in the atmosphere:
Fossil vs. biomass carbon contributions to atmospheric PAHs associated with PM10 and PM1.1
aerosols from residential area of suburban Tokyo : H.Kumada (Tokyo Midicine Collage)
16. The application of radiocarbon dating to archaeological excavation : T.Omori (Nagoya Univ.)
17. Sediment accumulation pattern of the incised-valley fills induced from the high-density AMS
radiocarbon dates: latest Pleistocene to Holocene example from the Paleo Oku-Tokyo Bay,central Japan : T.Nakanishi (National Institute of Advanced Industrial Science and Technology)
18. Sedimentary facies and 14 C dates of the latest Pleistocene to Holocene incised-valley fills from
Yoroigata, Echigo Plain, central Japan : S.Tanabe (National Institute of Advanced Industrial
Science and Technology)
19. Radiocarbon dating of the Fugusawa site in Aomori Prefecture 2005 : D.Kunikida (The Univ.
of Tokyo)
20. Information on fiber-tempered pottery : A.Minato (Nihon Univ.)
21. Study on transportation of particulate organic matter in river water from Hokkaido Island duringsnow-melting season by C-14 : J.Alam (Hokkaido Univ.)
22. The establishment of the method for 14 C distribution of dissolved organic carbon in sea water :S.Tani (Nagoya Univ.)
23. Development of analysis system of dissolved organic radiocarbon : T.Tanaka (JAEA)
24. Effect of paraloidT M , adhesive cement for fossils, to 14 C dating for fossil : H.Uno (NIES)
25. Geochemical study on human bones excavated from the Yuigahama site, Kamakura, Japan :M.Minami (Nagoya Univ.)
26. Seasonal variation of radiocarbon in urban atmospheric aerosol : K.Takahashi (NIES)
27. A study on pretreatment method for iodine isotopic ratio determination in seaweed : J.Kuwabara(JAEA)

6711. LIST OF PERSONNEL
Tandem Accelerator Complex
Y. Nagashima
T. Komatsubara
K. Sasa
S. Ishii
H. Kimura
H. Oshima
Y. Tajima
T. Takahashi
Y. Yamato
H. OtaR. SekiM. MoroDirector, Professor
Assistant Professor
Assistant Professor
Mechanical Engineer
Computer Engineer
Electric Engineer
Mechanical Engineer
Electric Engineer
Electric Engineer
Research Fellow
Former Professor
Administrative Stuff

Research Members
Inst. of Physics
T. AokiY. AokiT. Komatsubara
Y. MiakeA. Ozawa
K. Sasa
Inst. of Applied Physics

I. Arai
T. Nagatomo
M. Yamaguchi

S. Esumi
M. Onoda

S. Katoh
H. OtaE. Kita

N. Tomita

A. Uedono

H. Yanagihara

K. Takita

H. Tanimoto

H. KudoInst. of Material Science
T. Koyano

H. Mizubayashi

Inst. of Geoscience
M. Kurosawa

N. TaseInst. of Chemistry
K. SuekiInst. of Basic Medical Science
Y. Nagashima

68

Scientific Guests and Fellows
K. Awazu
T. Ikeda
T. Ohura
M. Yamazaki
T. Hayakawa
M. Kurokawa
T. Fukuchi
H. Baba
S. Nishimura
Y. Tagishi
A. Saito
S. Kubono
H. Yamaguchi
He Jianjun
H. Fujikawa
A. Guilherme
Y. Wakabayashi
N. Okumura
K. Matsuta
T. Nagatomo
T. Mihara
R. Matsumiya
T. Sumikama
I. SugaiY. Takeda
M. Oyaizu
H. Kawakami
T. Miura
K. Bessho
H. Matsumura
K. Masumoto
H. OguriJ. Hasegawa
J. Kaneko

National Lab. Advanced Industrial Science and Technology
Waseda Univ.
Tokyo Metropolitan Univ.
Tokyo Metropolitan Univ.
JAERI
RIKEN
RIKEN
RIKEN
RIKEN
RIKEN
CNS, The Univ. of Tokyo
CNS, The Univ. of Tokyo
CNS, The Univ. of Tokyo
CNS, The Univ. of Tokyo
CNS, The Univ. of Tokyo
CNS, The Univ. of Tokyo
Kyushu Univ.
Nagano College of Technology
Osaka Univ.
Osaka Univ.
Osaka Univ.
Osaka Univ.
RIKEN
KEK
KEK
KEK
KEK
KEK
KEK
KEK
KEK
Tokyo Institure of Technology
Tokyo Institure of Technology
Tokyo Institure of Technology

69

Graduate Students
Doctoral Degree Programs of Pure and Applied Science
Jo Ben Ho
S. Igarashi
M. Iijima
H. Masui
K. Miyakawa
Y. Nagata
M. OkaS. SakaiJ. Sawahata
N. Yagi
Master’s Degree Programs of Pure and Applied Science
H. Arai
T. Ebisawa
Y. Fujii
M. Furutani
M. Hasegawa
Y. Ikeda
Y. ItoH. Kasai
Y. Kikuchi
H. Mishiba
K. Nakamoto
T. Niida
A. Sasaki
T. SatoK. Shibata
K. Takao
R. Tanabe
Y. Tomita
N. Umada
H. Wakamatsu
K. Yamagishi
Master’s Degree Programs of Education

So Jong Wong
M. Nakazumi
M. Shimomura

M. Konno
M. Narisawa
H. Tokano

K. Fujiwara
T. Ishikawa
A. Kondo
T. Nishimura
T. Sugaya
Y. Toyota
T. Yasuno

D. Fukuhara
T. Isobe
K. Miki
A. Rikukawa
T. Takahashi
R. Uchiyama
S. YodaK. Iwamura
Y. Odajima

S. Kanda
H. Okaguchi

K. Yamaguchi
Master’s Degree Programs of Environmental Science
Y. Tosaki
Undergraduates
M. Furukawa
T. Kawamata
R. Sawai

J. Hagiwara
M. Minakawa
D. Yoshioka

Y. Hashizume
H. Nagami

70