UTTAC-88, 2019UTTAC
ANNUAL REPORT 2018

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

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

UTTACANNUAL REPORT 2018
April 1, 2018– March 31, 2019

UTTAC-88, 2019

Editors : Tetsuaki Moriguchi, Kimikazu Sasa, Yoshihiro Yamato, Masumi Matsumura,
Masao Sataka, Hiroshi Naramoto, and Hiroshi Kudo (editor-in-chief)

UTTAC ANNUAL REPORT is a series of issues, which include annual reports of
Tandem Accelerator Complex, Research Facility Center
for Science and Technology, University of Tsukuba.
Copyright © 2018 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, Japanannual@tac.tsukuba.ac.jp

PREFACE
This annual report covers researches carried out at University of Tsukuba Tandem
Accelerator Complex (UTTAC) during the fiscal year 2018 (1 April 2018 ~ 31 March2019). The topics include not only accelerator-based researches using the 6MV Pelletronand 1MV Tandetron accelerators, but also radioisotope-based researches including
positron annihilation spectroscopy and Mössbauer spectroscopy.
September 2, 2019
Editorial board-i-HIGH SCHOOL STUDENTS MEET ADVANCED SCIENCE AT UTTACIn FY2018, UTTAC has accepted totally 571 visitors, consisting of 397 high school students. Indeed, oneof the important roles of the UTTAC facility is the promotion of physical science to young generation.

Fig.1. sample

High school students listening to the staff’s explanation of a series of electronic control systems
at the experimental room of the Tandetron accelerator.

Number of yearly visitors to UTTAC from FY2013 to FY2018.

- ii -

CONTENTS

1. ACCELERATOR AND RELATED FACILITIES
1.1

Accelerator operation 2018 ················································································

1

1.2

Improvement of the Lamb-shift polarized ion source···················································

3

1.3

Approach to possible maximum energies of ions accelerated by the 6 MV tandem accelerator····5

2. NUCLEAR AND ATOMIC PHYSICS
2.1 Measurements of magnetic moments of 29P and 25Al···················································

7

2.2 Development of a position-sensitive detector using scintillating fibers······························

8

2.3 Generalization of a gain reduction model for the space charge effect in a wire chamber·········· 10

3. ACCELERATOR MASS SPECTROMETRY
3.1

Performance report of the Tsukuba 6 MV multi-nuclide AMS system in fiscal 2018··············

13

3.2

Challenge to the measurement of 90Sr by accelerator mass spectrometry − application toenvironmental samples····················································································

15

3.3

36

Cl record in the Antarctic ice core around the AD774/5 cosmic-ray event and developmentof 10Be AMS ······························································································
10

36

17

3.4

Measurements of cosmogenic Be and Cl in precipitation during 2015 − 2016················

19

3.5

Depth profiles of organic 36Cl derived from the Fukushima Dai-ichi Nuclear Power Plant ·····

21

129

3.6

Distribution of

I inventory in difficult-to-return zones in Fukushima Prefecture ··············

23

3.7

Anthropogenic iodine-129 in the Japan Sea and Okhotsk Sea during 2017−2018 ···············

25

3.8

Performance of Iodine-129 AMS measurements at the University of Tsukuba ···················

27

4. BEAM AND ISOTOPE APPLICATIONS
4.1

Free volumes introduced by fractures of CFRP probed using positron annihilation ·············

29

4.2

Preliminary micro-PIXE analysis of silicate glass particles released from Fukushima
nuclear plant·······························································································

31

4.3

Kinetic energy measurements of 10−100 keV ions using superconducting tunnel junction ···

33

4.4

3D imaging of hydrogen distribution in H-charged Al·······································

35

16

4.5

Reflection ERDA of hydrogen isotopes in DLC/Si using 15 MeV O ions······················

36

4.6

Development of TOF−E telescope ERDA for depth profiling of light elements at UTTAC···

38

4.7

Hydrogen desorption from GaN induced by thermal plasma jet annealing·······················

40- iii -

High-field Mössbauer measurements on Co-Ni spinel ferrites at successive stages ofsynthesis····································································································

42

4.9

Mössbauer spectra of Fe-based metallo-supramolecular polymers································

44

4.10

Influence of oxygen introduction on magnetic properties of epitaxial NdH2 thin films········

45

4.8

5. BEAM IRRADIATION EFFECT
5.1

PSoC device radiation tolerance evaluation toward space application······························

47

6. LIST OF PUBLICATIONS AND PRESENTATIONS
6.1

Journals ····································································································

49

6.2

Reviews and books························································································

54

6.3

Poster or oral presentations at academic meetings····················································

54

6.4

UTTAC seminars·························································································

62

7. THESES··········································································································

65

8. LIST OF PERSONNEL·····················································································

67- iv -

1.
ACCELERATOR AND RELATED FACILITIES1.1

Accelerator operation 2018

K. Sasa, S. Ishii, Y. Tajima, T. Takahashi, Y. Yamato, M. Matsumura, T. Moriguchi, A. Uedono
1 MV Tandetron accelerator
The operating time and the experimental beam time of the 1 MV Tandetron accelerator were 429 and180.1 hours, respectively, during the total service time in fiscal 2018. A total of 46 days was used for beam
experiments. A total of 135 researchers and students used the 1 MV Tandetron accelerator in fiscal 2018.
Figures 1 and 2 show classification of the accelerated ions and of the experimental purposes, respectively.
This accelerator was maximally used for RBS/ERDA which occupied 60.6% of the beam time. It should
be noted that 4.5% of the beam time was used for RBS/ERDA by external users.
We performed alignment adjustment for the beam transport because there was an axis deviation after
the earthquake in 2011. The accelerator tank was lifted up by about 1 cm for the alignment adjustment in
the periodic maintenance in March 2019.

Cu
1.7%

Beam test
3.5%

H
23.9%

Developments
17.6%
Education
15.2%

Cl
51.0%

He
21.2%

RBS/ERDA
60.6%

PIXE
3.1%

Cn
2.2%
Fig. 1. Accelerated ions by the 1 MV Tandetron
accelerator in fiscal 2018.

Fig. 2. Purpose of use of the 1 MV Tandetron
accelerator in fiscal 2018.

6 MV Pelletron tandem accelerator
The operating time and the experimental beam time of the 6 MV Pelletron tandem accelerator were1633.6 and 1286.4 hours, respectively, during the total service time in fiscal 2018. The total number ofoperation days was 115 in fiscal 2018. 60 research programs were carried out and a total of 459
researchers used the 6 MV Pelletron tandem accelerator in fiscal 2018. Figure 3 shows the beam time
histogram with respect to the terminal voltage. Figures 4 and 5 show classification of the accelerated ionsand of the experimental purposes, respectively. The operating time at the terminal voltage of 6 MV
accounted for 60.1% of all the beam time. This accelerator was used most often for AMS which occupied
69.4% of the beam time. The next 16.8% was occupied by IBA using a micro beam, mainly for analysis of
structural materials in the Strategic Innovation Promotion Program: SIP [1].
There was a major trouble in fiscal 2018 with the foil changer in the accelerator terminal, which caused1malfunction to circulate the carbon foil unit, as was the same trouble in the previous cases [2, 3]. We
opened the accelerator tank and repaired the foil changer in March 2019.

Terminal voltage (MV)

6
5
4
3
2
1
0.0

100.0

200.0

300.0

400.0

500.0

600.0

Beam time (hours)
Fig. 3. Beam time histogram as a function of the terminal voltage for the 6
MV Pelletron tandem accelerator in fiscal 2018.

Developments(Instruments
and Detectors) 1.5%
H
9.3%

I
20.1%

Radiation Resistance
Test 4.0%

He
4.25%

Nuclearphysics
7.0%

Mo
0.2%
Be
15.8%

Sr
5.7%
Ni
1.0%
Ti
0.15%
Ca
3.9%

C
0.05%

Cl
22.6%

S
Al
0.15% 1.9%

Education Beam test
0.1%
0.25%
Appropriative
project
0.95%

IBA（RBS/ERD
A/NRA)
16.8%

AMS
69.4%

N
13.1%
O
0.6%
F
1.2%

Fig. 4. Accelerated ions for the 6 MV Pelletron tandem
accelerator in fiscal 2018.

Fig. 5. Purpose of use of the 6 MV Pelletron tandem
accelerator in fiscal 2018.

References[1] SIP-IMASM: https://unit.aist.go.jp/tia-co/project/SIP-IMASM/index.html[2] K. Sasa et al., UTTAC ANNUAL REPORT 2016, UTTAC-86 (2017) 1.
[3] K. Sasa et al., UTTAC ANNUAL REPORT 2017, UTTAC-87 (2018) 1.

2

1.2

Improvement of the Lamb-shift polarized ion source

T. Moriguchi, Y. Yamato, A. Ozawa, M. Mukai, D. Kamioka, R. Kagesawa
The Lamb-shift polarized ion source (PIS) is one of the ion sources installed at the 6 MV Pelletron
tandem accelerator at UTTAC which has been operated since March 2016 [1]. PIS makes it possible toproduce highly polarized negative proton and deuteron beams whose spin polarizations are approximately
80%. At present, PIS is mainly used for measuring nuclear moments of unstable nuclei [2]. In FY2017, we
measured the spin polarization of the proton beam accelerated to 12 MeV, which was approximately 40%,
and found that the depolarization occurred during the beam transport from PIS to the beam course [3, 4]. In
this report, we refer to improvements for higher polarization as well as for stable operation of PIS.
One of the possibilities for the depolarization might be the electron exchange between the ions andresidual gas in the beam duct. Indeed, defects of attachment around the previous valve were found when astripper gas valve in the accelerator terminal was replaced with a new one in March 2018 [5]. It is therefore
probable that the SF6 gas in the accelerator tank leaks into the gas stripper canal, hence causing the
depolarization. After repairing the attachment, we measured the spin polarization of the polarized proton
beam at 12 MeV with a polarimeter using the p-4He elastic scattering. The experimental method is the sameas the previous one [3, 4]. The spin quantization axis was set to be perpendicular to the horizontal plane,
and accordingly the spin direction was either upward (spin-up) or downward (spin-down). The scatteredprotons were detected by two silicon detectors on the left and right sides of the polarimeter. Figure 1 showsenergy spectra measured with the silicon detectors, where the peak energy at ~370 channel corresponds tothe elastically scattered protons. In the present measurement, the spin polarization of the proton beam was
improved to approximately 60% in both spin-up and spin-down cases. This corresponds to a 20% increase
compared with the previous case [3, 4]. However, cause of the depolarization is not completely elucidated
yet. For example, the residual argon gas in the stripper canal, even when closing the stripper gas valve,might induce the depolarization.

Fig. 1. Energy spectra obtained with silicon detectors at the left (red line) and the right (blue line) sidesof the polarimeter. Shown in (a) and (b) are the results for spin-up and spin-down, respectively.

3

In FY 2018, we improved parts of PIS for its stable operation. Several electrodes for the extraction ofions in the duoplasmatron chamber were replaced with new ones because degradation of the vacuum
condition and frequent discharges occurred by the leak of silicone fluid for cooling the electrodes. One ofthese electrodes is of the cylindrical type referred to as “middle electrode (ME)” as shown in Fig. 2 (a). The
LaB6 filament is mounted in ME, and positive ions are extracted from the center hole of ME. The cesium
cell was also replaced with a new one because of the leak of circulating hot water which liquefies the cesium
vapor to return to the reservoir attached with heater. Figure 2 (b) shows a photo of the new cesium cell. At
present, we plan to change the variable leak valve for hydrogen gas supply to a high performance one.

Fig. 2. Photos of (a) the middle electrode and (b) the cesium cell, which replaced the old ones in FY 2018.

References[1] K. Sasa et al., UTTAC Annual Report 2015, UTTAC-85 (2016) 1.
[2] A. Ozawa et al., this Annual Report §2.1.
[3] T. Moriguchi et al., UTTAC Annual Report 2017, UTTAC-87 (2018) 3.
[4] T. Moriguchi et al., Proceedings of Science, PSTP2017 (2018) 018.
[5] K. Sasa et al., UTTAC Annual Report 2017, UTTAC-87 (2018) 1.

4

1.3 Approach to possible maximum energies of ions accelerated by the 6 MV
tandem accelerator
M. Sataka, T. Takahashi, H. Naramoto, H. Kudo, K. Sasa
A series of ion acceleration tests with the 6MV tandem accelerator has been continued for 3 years [1, 2].
Actually, at three terminal voltages of 1, 3, and 6 MeV the beam current of the accelerated ion is measured
as a function of the ion’s charge state. For a given ion species, the highest charge state determines the highest
beam energy obtainable from the accelerator. In this fiscal year, N, Al, S, and Mo ions were tested. Here,
we describe the test results at the terminal voltage of 6 MV.
Figure 1 shows the beam current distributions of sulfur ions as a function of the charge state at theterminal voltage of 6 MV. Either argon gas or a carbon foil was used as a charge-changing stripper at thehigh-voltage terminal. The gas pressure was about 5−7 μPa, and the thickness of the carbon foil was about
5 μg/cm2. When the foil stripper is used, the incident ion beam was weak enough to avoid radiation damageof the foil. The ion current distribution for the foil stripper shifts to higher charge state by 3 than for the gas
stripper. For both the foil and the gas strippers, the practically available maximum energy obtained for sulfur
ion is 66 MeV, employing the charge state of 10.
10000

Beam Current (nA)

1000

100

10

foil(x100)
gas

1

0.1
1

2

3

4

5

6

7

8

9

10

11

Ion Charge State
Fig. 1. Ion beam current distribution for sulfur ion at the terminal voltage of 6MV. Either the gas
or the foil stripper was used at the high-voltage terminal.

In FY2018, we tested injection of negatively charged molecular ions (including cluster ions) to obtain
ion beams of N, Al and Mo. In this case, the beam energy cannot be determined uniquely from the terminal
voltage and the ion’s charge state. The maximum acceleration energies in this test are about 39, 51, 65, and
71 MeV for N, Al, Mo, and W ions, respectively. Table 1 shows the summary of the acceleration test of N,
Al, Mo and W ions. Table 2 shows the revised summary for injection of negatively charged single-atom ion,5

which is based on the data collected from 2016 to 2018 for the 6 MV terminal voltage. For atomic Al(monomer) acceleration, the beam current is about one fifth of that for Al2 (dimer) ion.
Table 1. Ion current distribution of N, Al, Mo, and W at the terminal voltage of 6MV.
The measured beam intensity is shown by the symbols: ○: ≥ 1nA, △: <1nA.
Charge
state

N

Al

Mo

W

△

△

14
13
12
△

11
10
9

◯

△

◯

8

◯

△

◯

7

◯

◯
◯

6

△

◯

5

◯

◯

4

◯

3

◯

2

◯

◯
◯

1

Table 2. The summary of the acceleration test for atomic negative ion injection at the terminal voltage of
6MV, carried out from 2016 to 2018. The measured beam intensity is shown by the symbols: ○: ≥ 1nA,△: <1nA. The results obtained with the foil stripper are shown in red.
Charge Energy
state （MeV）

Br

Ag

I

14

90

△

△

◯

△

13

84

△

△

◯

△

12

78

11

72

10

66

9

60

8

54

7

48

6

42

5

36

4

30

3

24

2

18

1

12

H

He

Li

B

C

O

F

Al

Si

S

Cl

○

◯
◯
◯
◯

◯
◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

○

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯

◯
◯

◯

◯

◯

◯
◯

◯

◯

◯

◯
◯

◯

◯

◯

△
◯

◯

◯
◯

Au

○

◯

◯

Ni

◯

References[1] M. Sataka et al., UTTAC Annual Report 2016, UTTAC-86 (2017) 9.
[2] M. Sataka et al., UTTAC Annual Report 2017, UTTAC-87 (2018) 5.

6

◯

2.
NUCLEAR AND ATOMIC PHYSICS

2.1

Measurements of magnetic moments of 29P and 25Al

A. Ozawa, T. Moriguchi, Y. Yamato, R. Kagesawa, D. Kamioka, M. Mukai
We are attempting to produce polarized unstable nuclei by using polarized proton beams for the aim ofmeasuring nuclear moments of unstable nuclei. In FY2017, we have succeeded to produce and detectpolarized unstable nuclei by using Ep=12 MeV with a Si target [1].
In FY2018, we have tried to measure nuclear magnetic
moments (μ) of 29P (T1/2=4.2 s) and 25Al (T1/2=7.2 s) byusing our nuclear magnetic resonance system for β-rays(β-NMR system). The μ values of 29P and 25Al have beenreported in Refs. [2] and [3], respectively. Experimental
setup in our β-NMR system was already described in Ref.
[1]. In the present work, a 0.5 mm thick Si target placed inour β-NMR system was irradiated with a polarized proton
beam accelerated to 12 MeV by the 6 MV tandem
accelerator. The proton polarization-degree was about 70 %.
In this work, to search μ for 29P and 25Al in our β-NMR
system, we changed the static magnetic field instead of theradio frequency (RF) scanning, where RF was fixed to
4.75-5.25 MHz.
Figure 1 shows the NMR spectrum observed in thepresent experiment. We observed two clear resonances inthe spectrum. In Fig. 1, values of the current
corresponding to the previously measured μ for 29P and
25

Fig. 1. NMR spectrum measured using a 12 MeV
polarized proton beam with a Si target. RF was
fixed to 4.75-5.25 MHz. Open circles indicate thedata without RF. Arrows show values of thecurrent corresponding to the previously measured
μ for 29P (left) and 25Al (right), respectively.

Al are shown by arrows. Resonances observed in the present work are well consistent with the previously

measured μ. Thus, we succeeded to measure μ of 29P and 25Al in our β-NMR system. In the next step, we
will try to measure unknown nuclear moments, such as μ of 30P (T1/2=150 s).
References[1] A. Ozawa et al., UTTAC Annual Report 2017 (2018) 7.
[2] K. Sugimoto et al., in Hyperfine Interactions in Excited Nuclei, edited by G. Goldring and R. Kalish(Gordon and Breach, New York, 1971), p. 325.
[3] T. Minamisono et al., Phys. Rev. C 14 (1976) 376.

7

2.2

Development of a position-sensitive detector using scintillating fibers

T. Yamaguchi1,2 , Y. Inada2 , S. Hosoi2 , R. Kagesawa, T. Moriguchi, A. Ozawa
In this study, we develop position-sensitive detectors using thin scintillating fibers and shaped plastic
scintillators for the Rare-RI Ring facility at RIKEN RI Beam Factory [1]. In high-energy RI beam facilities, well-established gas position-sensitive detectors such as parallel plate avalanche counters (PPAC) [2]
are used for beam diagnostics. As the Rare-RI Ring facility has many focal planes in an approximately
160-m-long injection beam line, numerous detectors are required for beam diagnostics. However, operating and maintaining these types of detectors can be expensive and often time-consuming. In addition,
in-ring position-sensitive detectors are necessary for precise beam tuning during the injection phase. Because the Rare-RI Ring stores only a single particle at every injection, conventional beam instruments are
not available. Thus, simple, compact, low-cost position-sensitive detectors with single ion sensitivity must
be developed.
Thus far, we have developed a simple prototype detector that uses plastic scintillation bars with multipixel photon counters using a simple readout method [3]. The prototype has been shown to measuresuccessfully the position distributions of heavy ions. This detector can be used in the injection beam line
as well as in the storage ring on a movable platform. The present study is an extension of this direction.
We produced a prototype of a long scintillating fiber detector to observe decay particles of stored ionsin the storage ring. The detector will be installed along the circumference of an approximately 60-m
storage ring. The original concept and results of experiments conducted at the HIMAC facility [4] will be
published elsewhere [5].
In this study, we performed a detector test experiment at the 6-MV tandem accelerator facility at the
University of Tsukuba. The prototype consists of nine scintillating fibers (Kuraray SCSF-78J, 2 × 2
mm and 2 m long) arranged to form a flat plane of 18 mm × 2 m as shown in Fig. 1. Each end of thenine scintillating fibers was assembled and connected to a common multi-pixel photon counter (MPPC
S13360-6075CS Hamamatsu).

Fig. 1. Photograph of nine scintillating fibers forming a plane. The inset shows the cross section of thenine fibers before being connected to the MPPC.

A 12-MeV proton beam was used to test the detector response. The beam was incident on a 2.5-µ m
1 Cross appointment at the University of Tsukuba
2 Department of Physics, Saitama University

8thick Au foil placed at the target chamber of the A7 course. The protons scattered at 30◦ were directedon the prototype. By moving the detector, we changed the position of the beam spot every 40 cm. The
timing and charge differences of the scintillation light pulses propagated to each end of the scintillatingfibers were measured.
A position correlation was successfully observed, as shown in Fig. 2, where the plotted ratio Tratio issensitive to the beam hit position and is defined as
Tratio =Tleft − Tright,Tleft + Trightwhere Tleft and Tright are the timing of the left and right fibers, respectively, as measured by a time-todigital converter (TDC). The position resolution was approximately 2 cm. The charge difference wasapproximately 6 cm, the result that must be improved. Further developments are ongoing.
!"#

!"$

)('&%

!"!

!"$

!"#
*!

!

*!

+),('()-./012

Fig. 2. Position correlation of the timing difference observed for the proton beam.

References[1] A. Ozawa et al., Prog. Theo. Exp. Phys. 2012 (2012) 03C009.
[2] H. Kumagai et al., Nucl. Instr. Meth. Phys. Res. B 317 (2013) 717.
[3] K. Wakayama et al., JPS Conf. Proc., to be published.
[4] M. Kanazawa et al., Nucl. Phys. A 746 (2004) 393c.
[5] K. Inomata et al., JPS Conf. Proc., to be published.

9

2.3

Generalization of a gain reduction model for the space charge effectin a wire chamber

Y. Kato1 , K. Fujii1 , S. Kajiwara1 , T. Mogi1 , N. Nagakura1 , D. Sekiba, Y. Sugisawa, S. Yamashita2
In our neutron lifetime precise measurement in J-PARC, we monitor and collect the tracks of protonand β -ray coincidently in a wire chamber. Under the condition that the parameters of the wire chamber are
optimized to the β -ray detection, the output linearity for protons is crucially suffered from gain reduction
due to the space charge effect. In order to collect the desirable events correctly, it is necessary to obtain
the gain reduction factor s based on a phenomenological model.
A gain reduction model was previously proposed taking into account the self-induced space charge
effect [1]. In this model, s is expressed as follows,s≡log(1 + f G0 dE
dl )f G0 dE
dl,(1)where f is a constant factor including all microscopic characteristics of the space charge effect, which
determines the absolute scale of gain reduction, G0 is the multiplication factor without the space charge
effect, dE/dl is the energy loss per wire length.
We have conducted experimental verification of this model since last year with a multi-wire drift
chamber (MWDC) filled with a mixed gas of He and CO2 and a proton beam from the Tandetron accelerator at UTTAC. As a result, we determined the factor f under the condition of 85 kPa He gas and 15 kPa
CO2 gas, as shown in Fig. 1, and succeeded in correcting the gain reduction, as is seen in Fig. 2. For
details, see Ref. [2].

Fig. 1. Values of f derived for the proton energies of
E p =1.35 and 2.00 MeV as a function of the applied
anode wire voltage. The f values seem to be a constantwithin the present uncertainties.

1 Graduate School of Science, University of Tokyo
2 International Center for Elementary Particle Physics, University of Tokyo

10

Fig. 2. The experimental energy deposit
distributions with and without the correction of the gain reduction, together withthe simulation results.

Although the validity of this model has been proved as described above, it is necessary to re-determine
f in advance for application of the current model to other measurement. Hence, in this study, we aim togeneralize this model, and in particular to evaluate the gas dependence of f.
In the model, f is defined as f ≡ eBC/2πε aw, where e is the elementary charge, a is the anode wireradius, w is the average energy loss per electron-ion pair creation by the incident charged particle (wvalue), B is a coefficient under the assumption that the multiplication factor exponentially depends on theelectric field, and C is a coefficient describing the space charge effect [2] which should be approximately
1. According to the Diethorn’s formula [3], assuming the Townsend coefficient α to be proportional to theelectric field, the coefficient B should be proportional to a/w. Therefore f should be proportional to 1/w2 .
To verify the dependence of f on the gas condition, we are going to measure gain reduction under
several gas conditions. Change in the gas condition should lead to the change in the diffusion coefficientduring electron drift, and therefore, affect the gain reduction. To extract only the effect of diffusion, it isnecessary to measure the gain reduction while changing the total pressure of the same gas.
At present, MWDC is upgraded by implementation of the field cage to stabilize drift electric fieldand expansion of the sense area by increasing the number of wires, as shown in Fig. 3. In addition, we
acquired data for 2 MeV H+ with upgraded MWDC filled with a mixed gas of 85% He and 15% CO2 toconfirm the reproduction of the previous result in the current setup. The total gas pressure was changed to40, 60, 80, and 100 kPa to evaluate the effect of electron diffusion during drift step. Analysis is currently
in progress.
The next step is to measure the gain reduction with different gases. We are planning to use a mixed
gas of 90% Ar and 10% CH4 , and finally to verify w-dependence of f.
Field cage (~400V/cm)

150 mm}C12

150 mm↓Drift HV plate (-3kV)↑Capture HV plate (200V)

Cathode
wires
(GND)

○C06

}C01
}C00
A11

A00

wire pitch: 6mm◉ anode (φ20um)
field(φ50um)○ cathode (φ50um)

Anodes (1700V) & Fields (GND)◉ read-out○ read-out only upper layer

Fig. 3. The schematic layout of the upgraded MWDC.

References[1] Y.Arimoto et al., Nucl. Instr. Meth. Phys. Res. A 799 (2015) 187.
[2] N. Nagakura et al., Prog. Theor. Exp. Phys. 013C01 (2018).
[3] W. Blum et al., “Particle Detection with Drift Chambers”, Springer (2008).

11

12
13
25

2layer

3.
ACCELERATOR MASS SPECTROMETRY

3.1

Performance report of the Tsukuba 6 MV multi-nuclide AMS system infiscal 2018

K. Sasa, T. Takahashi, K. Takano, Y. Ochiai, Y. Ota, M. Matsumura, T. Matsunaka1, A. Sakaguchi,
K. Sueki
The AMS system on the 6 MV tandem accelerator was operated for a total of 55 days in fiscal 2018.
We measured 735 samples in total dealing with rare radionuclides such as 10Be, 26Al, 36Cl, 41Ca, 90Sr and129

I shown in Table 1. Figure 1 shows a breakdown by types of measured nuclides. Figure 2 showsmonthly-measured nuclides from April 2018 to March 2019. 36Cl and 129I were measured most frequently
in fiscal 2018 in order to investigate the radioactive contamination in rainwater and soil samples, causedby the Fukushima Daiichi Nuclear Power Plant accident. 129I was also applied for the tracer of oceanic
circulation in the Japan Sea. 10Be and 36Cl were applied for the tracer of cosmic ray events in the ice coreand variations of solar activity. In addition, we have tried to develop new techniques for 90Sr-AMS.
Table 1. Number of measured samples infiscal 2018.

Nuclides
Be-10
Al-26
Cl-36
Ca-41
Sr-90
I-129
Total

Number
180
13
196
23
29
294
735

Be-10
24%

I-129
40%

Al-26
2%

Cl-36
27%

Sr-90
4% Ca-41
3%

Fig. 1 Measured nuclides by the multi-nuclide
AMS system in fiscal 2018.

140

100
80
60

maintenance

Number of pieces

120

40
20
0

Apr-18 May-18 Jun-18

I-129
Sr-90
Ca-41
Cl-36
Al-26
Be-10

Jul-18 Aug-18 Sep-18 Oct-18 Nov-18 Dec-18 Jan-19 Feb-19 Mar-19

Change in month
Fig. 2. Monthly-measured nuclides by the multi-nuclide AMS system from
April 2018 to March 2019.
1

Kanazawa University13

We have developed ultrasensitive detection techniques for 10Be, 14C (graphite and CO2), 26Al, 36Cl,
41

Ca, and 129I in isotopic-ratio ranges of 10−10 to 10−16 with the multi-nuclide AMS system. AMS has

satisfactory performance for analysis of cosmogenic nuclides in the geo-environmental research. In fiscal
2018, we developed the sulfur removal method to reduce 36S contamination in 36Cl AMS. AgCl samples
were pressed into an AgBr backing in a large Cu sample cathode (6 mm diameter). The sensitivity
improvement due to the suppression of 36S has been investigated [1]. 36Cl measurements were performed
at a 6.0 MV terminal voltage with a carbon stripper foil of 4.8 μg cm−2. The analyzed charge state was 8+,
hence 36Cl8+ was injected into the detector at 54.0 MeV. A Si3N4 foil of 75 nm thickness was used for thedetector window under an isobutane pressure of 38 Torr. 36Cl− beam transmission was ~10%. AgCl blanksamples were prepared from ACS-grade NaCl (Fisher Scientific, USA). The 36Cl/Cl background was lessthan 3 × 10−15 with a run time of 500 s. Table 2 shows the performance summary of the Tsukuba 6 MV
multi-nuclide AMS system since for the first two years of operation since 2016 [2].
Table 2. Performance summary of the Tsukuba 6 MV multi-nuclide AMS system.
Isotope

10

Be

14

C

26

Chemical form

BeO

Graphite, CO2

Al2O3

Injected ion

BeO−

C−

Typical ion current (μA)

9125 [CO2]− 60 ( C−)

6.0

Terminal voltage (MV)
Detected ion (stripper)16

1 − 5 ( Be O−)

10

Be (gas)

14

Ca

129

AgCl

CaF2

AgI

Al−

Cl−

CaF3−

Ι−

27

5 − 15 ( Cl−)

0.2 ( Al−)

5.0

3+

36

Al

35

6.0

4+

26

C (gas)

41

Cl

40

6.0

5+

36

Al (gas)8+

Cl (foil)19

0.5 ( Ca F3−)
6.0
41

5+

Ca (foil)

l

1−8 (

127 −

I)

5.0
129 5+

I (gas)Beam energy (MeV)

20.3

25.0

36.0

54.0

32.5

30.0

Transmission (%)

30

40

25

10

10

10

Havar (5 μm) + Ar
(71.5 Torr)

−

−

−

−

−

Si3N4 (75 nm)

Si3N4 (75 nm)

Detector conditions
Absorber cell
Window material (thickness)

Mylar (6 μm)

Mylar (6 μm)

Detector gas (pressure)P10 (75.5 Torr)

P10 (70 Torr)

120

115 (Graphite)2

2.7 × 10−11

1.4 × 10−12

0.65

−

2

0.2 (Graphite)
0.6 (CO2)Counting rate (cps)Sample to reference ratio
Ratio of measured to nominal ratios

Precision (%)

Si3N4 (75 nm)

Polyester (1.5 μm)

Isobutane (16 Torr)

Isobutane (19 Torr)

65

15

8.5

7.4 × 10−11

1.0 × 10−11

1.2 × 10−10

8.38 × 10−12

0.50

0.50

0.70

0.90

3

2

3

1

<6 × 10−15<3 × 10−15<3 × 10−15<1 × 10−14

Isobutane (19.5 Torr) Isobutane (38 Torr)- 16

Background (atomic ratio)<1 × 10−15~2.4 × 10(Commercial
Graphite)~5 × 10

- 15

(CO2)

References[1] S. Hosoya et al., Nucl. Instr. Meth. Phys. Res. B 438 (2018) 131.
[2] K. Sasa et al., Nucl. Instr. Meth. Phys. Res. B 437 (2018) 98.

14

3.2

Challenge to the measurement of 90Sr by accelerator mass spectrometry− application to environmental samples

A. Sakaguchi, S. Yamasaki, S. Asai, K. Sasa, T. Takahashi, Y. Ochiai, K. Takano, M. Honda1,
M. Matsumura, K. Sueki
The goal of this study is the measurement of low-level strontium-90 (90Sr, T1/2=28.90 year), which has
rarely been measured in environmental samples due to the complicated nature of its chemical separation andthe time-consuming requirements for such measurements. Nevertheless, its behavior and biological impact areimportant. To achieve the purpose, a new and efficient chemical separation method has to be developed andcombined with accelerator mass spectrometry. Furthermore, it is necessary to find appropriate Sr
precipitates/salts, which efficiently accumulate Sr from the chemically separated solution and, accordingly,
provide an intensive Sr beam required for accelerator mass spectrometry.
Experiment 1. Precipitation methods for Sr targets

To achieve a high Sr precipitation yield from apurified Sr solution, SrCO3, SrSO4, Sr3(PO4)2, Sr(COO)2 (SrO− beam emitter) and SrF2, SrF2+EuF3 (Sr:Eu= 1:1, 1:4, 1:9) (SrF3- emitter) precipitations were produced, and the remaining supernatant Sr wasmeasured with ICP-MS. The precipitations thus obtained were dried/ashed and pressed into the cathodes
for the sputter ion source. Each cathode was sputtered with Cs+, and the Sr beam intensity was measured
using a Faraday cup. Analogue samples of SrO+ZrO2 and SrF2+ZrF4 were also sputtered with Cs+ toobserve the intensities of interference Zr beams (ZrO- or ZrF3-)
Experiment 2. Purification of Sr from natural water samples

In addition to the Sr resin method

above [1], we hired MC1GEL (cation exchange resin) to remove zirconium (Zr) from the samples.
Furthermore, a self-distilled reagent was also used for the final Sr solution. In combination with theappropriate precipitation method from Experiment 1, a blank sample was prepared. The signal counts from
Zr for the blank sample were checked with an ionization chamber after accelerating the ions.
Experiment 3. Application of a lanthanide co-precipitation method

As for a lanthanide-fluoride

co-precipitation method from Experiment 1, lanthanum (La), praseodymium (Pr), europium (Eu), thulium(Tm) and lutetium (Lu) coprecipitation methods were attempted. The precipitation yields and Sr ion beam
intensity of each precipitation were observed using the same method as in Experiment 1.
For all the Sr precipitations, except for Sr3(PO4)2 and SrF2, the precipitation rates are in the range 89.9
to 98.8%. Of these precipitations, the best is thought to be SrF2+EuF3, which gives the highest Sr beam
intensity and the lowest Zr intensity. The newly developed purification method for Sr showed a higher Srchemical yield with a lower Zr intensity. In fact, the Zr count-rate of more than 100 kcps in the case of theprevious method could be decreased to 1.5 kcps, and 90Sr in an analogue riverine water sample(IAEA-PT-222) was measured as 90Sr/88Sr = 4.98×10−10 using ca. 400 ml of the sample. As for thelanthanide-fluoride co-precipitation methods, they showed a variety of Sr beam intensities depending on
the lanthanide element used. Interestingly, a correlation between the Sr beam intensity and the first

1

VERA, Univ. of Vienna

15ionization energy of lanthanide was found. The reason for this correlation is currently not clear, suggestingthat further research is needed using other lanthanide elements.
Reference[1] S. Hosoya, Developments of accelerator mass spectrometry for hardly measurable nuclides by 6MV
tandem accelerator, Master thesis 2018, University of Tsukuba.

16

3.3

36

Cl record in the Antarctic ice core around the AD774/5 cosmic-ray
event and development of 10Be AMS

K. Takano, K. Sasa, T. Takahashi, M. Matsumura, Y. Ochiai, K. Sueki, F. Miyake1, K. Horiuchi2,
H. Matsuzaki3
Galactic cosmic rays are high energy particles that come to the earth from outside the solar system.
They interact with atoms and molecules in the atmosphere, which is essential for the production ofcosmogenic nuclides such as 14C, 10Be, 26Al, and 36Cl. Therefore, concentrations of cosmogenic nuclides
reflect intensities of incoming cosmic rays. Miyake et al. [1] measured 14C contents in tree rings with atime resolution of 1- to 2-year and found a large 14C increase from AD 774 to AD 775 (AD 774/775 event).
Moreover, Miyake et al. [2] measured 10Be concentrations for the period approximately AD 763 – 794 in
the Antarctic Dome Fuji ice core, and detected a significant increase of the 10Be concentration around AD
775.
A multi-nuclide analysis provides original cosmic ray information, e.g. an energy spectrum of cosmic
rays. We therefore investigated the temporal variation of 36Cl concentration, corresponding to the case foranother cosmogenic nuclide, in the ice core samples from the Dome Fuji around the periods where cosmic
ray events were identified. 36Cl is mainly produced in the atmosphere by the spallation reaction ofincoming cosmic rays with 40Ar, and it falls down and deposits in the ice core. We measured 36Cl
concentrations around AD 774/5 event using the 6 MV AMS system at the University of Tsukuba [3].
Each sample was taken at a depth interval of 20 cm which corresponds to a time resolution of ~4 year. We
added Cl carrier of ~0.5 mg to each sample (approximately 100 − 120 g in weight), which resulted in themeasured 36Cl/Cl ratios of 8.0 × 10−14 – 12.3 × 10−14 around the AD 774/5 event. Table 1 shows that the36

Cl concentrations in the Dome Fuji ice core are in the range of 0.9 × 104 to 1.4 × 104 atoms g−1.
Table 1. 36Cl concentrations in the Dome Fuji ice core around the AD 774/5 event.
Sample ID

Depth

Year

WeightCl conc.
4

Error
4

(m)

(AD)

(g)

(×10 atoms g )(×10 atoms g−1)

DF1-123-11 ~ DF1-123-14

57.6

792.7

121.9

0.89

0.05

DF1-124-1 ~ DF1-124-5

57.8

788.8

118.8

1.09

0.05

DF1-124-6 ~ DF1-124-10

57.9

784.6

118.6

1.06

0.10

DF1-124-11 ~ DF1-124-15

58.1

780.4

117.9

1.38

0.09

DF1-124-16 ~ DF1-125-4

58.2

776.0

100.0

0.94

0.08

DF1-125-4 ~ DF1-125-10

58.4

770.5

110.0

0.96

0.05

DF1-125-11 ~ DF1-125-15

58.5

765.0

112.7

0.89

0.06

1

Nagoya University
Hirosaki University
3
The University of Tokyo
2

17

−1

We confirmed the increase of both 10Be and 36Cl concentrations around AD 780. Similar increase of10

Be and 36Cl fluxes was reported by F. Mekhaldi et al. [4], who analyzed ice core samples from Greenland.

These results indicate that the AD 774/5 event was confirmed in both hemispheres.
In this study, it is of essential importance to compare the 36Cl-AMS data with the 10Be-AMS data.
Therefore, we have developed 10Be-AMS by the Tsukuba-AMS system for measurements of 10Be in the icecore samples. For 10Be-AMS, 10BeO− was extracted from BeO samples mixed with Nb and accelerated to
6.0 MeV. The maximum 9BeO− beam current was ~ 7 μA from the ion source. Figure 1 shows 2D spectra
for the standard reference material KNBe5-1 (10Be/Be = 2.709 × 10−11) [5], measured with a run time of
120 s, and for 10Be from a blank sample, measured with a run time of 300 s. As a result, we have achieved
the 10Be/Be background level of 3 × 10−15 and confirmed the extraction of enough 9BeO− beam current
from the ion source. At present, we have measured 10Be concentrations in the rain, meteorite samples andso on.

Fig. 1. Comparison of measured 2D spectra for a standard reference sample (left) and ablank sample (right).

References[1] F. Miyake et al., Nature 486 (2012) 240.
[2] F. Miyake et al., Geophys. Res. Lett. 42 (2015) 84.
[3] K. Sasa et al., Nucl. Instr. Meth. Phys. Res. B 437 (2018) 98.
[4] F. Mekhaldi et al., Nature Com. 6 (2015) 8861.
[5] K. Nishiizumi et al., Nucl. Instr. Meth. Phys. Res. B 258 (2007) 403.

18

3.4

Measurements of cosmogenic 10Be and 36Cl in precipitation during
2015 − 2016

Y. Ochiai, K. Sasa, Y. Tosaki1, T. Takahashi, M. Matsumura, K. Takano, Y. Ota, K. Sueki
10

Be (half-life = 1.36 × 106 years) and 36Cl (half-life = 3.01 × 105 years) are cosmogenic nuclides, which

are produced by nuclear reactions between cosmic rays and elements constituting the Earth, e.g., 14N(n,X)10Be or 40Ar(n, X)36Cl. After the production, 10Be and 36Cl are attached to rainwater or aerosols and aredeposited on the surface of the Earth. In the present work, 10Be and 36Cl deposition fluxes were measured
with monthly rainwater samples. It is found that the 36Cl deposition flux correlates with the 10Be flux, while
the ratio of 36Cl to 10Be fluctuates monthly.
We have collected monthly rainwater samples at the University of Tsukuba (36°06’N, 140°06’W) sinceApril 2004. In this study, 10Be and 36Cl deposition fluxes during 2015 − 2016 were analyzed. After adding
Be carrier of 0.5 mg, Be2+ and Cl−, which exist in the chemical forms of Be and Cl in the rainwater samples,
were extracted by the ion exchange method. Be2+
was precipitated as Be(OH)2 with 15 M NH4OH
and converted to BeO by heating in the electric
furnace at 850 °C. Cl− was precipitated as AgClwith 0.3 M AgNO3 and washed with ultrapure
water and ethanol. 10Be and 36Cl were measured
with the accelerator mass spectrometry system at
UTTAC [1]. The background values are 10Be/Be <1.0 × 10-15 and 36Cl/Cl < 3 × 10-15, and theprecision for both 10Be and 36Cl analyses is ~2%.
The measured values were corrected with KN
standards prepared by Nishiizumi [2, 3].
Figure 1 shows (a) the temporal variation of
10

Be and36

Cl deposition fluxes and (b)precipitation amount at the sampling site during
2015 − 2016. The 36Cl measurement of the sample
in January 2016 was unsuccessful due to serious
contamination of sulfur. The

10

Be and36

Cldeposition fluxes range from (1.70 ± 0.03) × 102
to (8.8 ± 0.6) × 102 atoms m−2 s−1 and from 9.2 ±1.3 to (1.14 ± 0.04) × 102 atoms m−2 s−1,
respectively. The
with

1

36

Cl

10

Be deposition flux correlates

strongly,

corresponding

toFig.1 (a) 10Be and 36Cl deposition fluxes and (b)precipitation amount during 2015 − 2016.

theGeological Survey of Japan, AIST

19

correlation number r = 0.7. Although previous
studies concluded that 10Be or 36Cl deposition flux
correlates with precipitation amount [4, 5], thepresent work demonstrates that the correlation
between precipitation and either 10Be or 36Cl is as
weak as r = 0.5 and 0.3, respectively. The strong
correlation between 10Be and 36Cl is caused not by
precipitation dependence of the deposition flux,
but by their similar behavior in the environment.
Figure 2 shows monthly variation of the ratio
36

of Cl to 10Be deposition flux during 2015 − 2016.
36

10

The average of the monthly ratio Cl/ Be = 0.079

Fig. 2. Monthly variation of the ratio of 36Cl to 10Be
deposition flux during 2015 – 2016.

± 0.002 is lower than the ratio of 36Cl/10Be = 0.10
± 0.01 which was estimated from the production rates in the whole Earth [6]. This would indicate that 10Be
or 36Cl is deposited heterogeneously on the surface of the Earth. Hence, further investigations are needed tounderstand the mechanism. We now plan to measure rainwater samples in other sites.
References[1] K. Sasa et al., Nucl. Instr. Meth. Phys. Res. B 437 (2018) 98.
[2] K. Nishiizumi et al., Nucl. Instr. Meth. Phys. Res. B 258 (2007) 403.
[3] P. Sharma et al., Nucl. Instr. Meth. Phys. Res. B 52 (1990) 410.
[4] I. Graham et al., Geochim. Cosmochim. Ac. 67 (2003) 361.
[5] F. M. Phillips, Chlorine-36 In: Environmental Tracers in Subsurface Hydrology, P. G. Cook and A. L.
Herczeg (Eds.), Kluwer Academic (2000) 299.
[6] J. Masarik and J. Beer, J. Geophys. Res. 114 (2009) D11103.

20

3.5

Depth profiles of organic 36Cl derived from the Fukushima Dai-ichi
Nuclear Power Plant

Y. Ota, K. Sueki, T. Takahashi, M. Matsumura, S. Hosoya, K. Takano, Y. Ochiai, T. Matsunaka1, Y. Satou2,
K. Sasa.
A large amount of radionuclide was released into the environment by the Fukushima Dai-ichi Nuclear
Power Plant (FDNPP) accident that has been caused on March 11, 2011 and afterwards. The long-lived
radionuclide, 36Cl (T1/2 = 3.01 × 105 yr) might also be released. However, there were few reports quantifying
36

Cl with environmental samples because the analysis of 36Cl requires an AMS system [1]. Therefore, wemeasured the ratio 36Cl/Cl of chloride in soil water with 31 surface soil samples around the FDNPP, andreported high values of the ratios [2, 3].
In soil, chlorine exists as chloride in soil water (Clinorg), chlorinated organic matter (Clorg), and chloride
in minerals (Clmineral). In the past, chlorine was believed to be present in soil only as Clinorg. However, recent
studies have shown that Clinorg is easily converted to Clorg by biotic and abiotic processes [4, 5]. Thus, 36Cl
released from the FDNPP accident was probably deposited as Clinorg and later converted partly to Clorg.
Therefore, we also have to measure 36Cl/Cl of Clorg in order to investigate whether 36Cl released from the
FDNPP accident remains as Clorg.
We used 30-cm-long soil cores at Namie-machi, Fukushima (37° 33′ 39″E, 140° 49′ 41″N) on June 12,2013, June 17, 2016 and September 10, 2017, whose 36Cl/Cl ratios of Clinorg have already been measured[3]. After acid extraction of Clinorg [3], the soil was vacuum-freeze-dried and grinded using a mortar andpestle.
Separation procedure of Clorg from the soil was developed by referring to the method for 129I analysis insoil by AMS [6]. In this procedure, the soil is combusted and Clorg is decomposed into HCl or Cl2. These
volatile chlorines are collected as chloride ions with absorbent solution containing H2O2. The combustion
apparatus is shown in Fig.1. The soil sample of about 2 g in a ceramic boat was combusted by tubular
furnace at 550℃ under a flow of O2 gas. The ceramic boat was inserted slowly to the tubular furnace taking
10 minutes and combusted at the middle point for 15 minutes. The volatilized chlorine was collected with
120 mL of trap solution containing 0.5% H2O2, 2.7 mM Na2CO3 and 0.3 mM NaHCO3. Then, 30% H2O2 of
5 mL was added to the absorbent
solution and it was left overnight. We
have to remember that the volatilechlorine cannot be trapped in absorbent
solution by incomplete combustion. In
this case, Clorg is not decomposed.
Therefore, we combusted a little soil
with O2 gas flow of over 1000 mL/min.
1
2

Fig.1. The combustion apparatus of soil for Clorg separation.

Kanazawa University
Japan Atomic Energy Agency (JAEA)

21

It is notable that we used the low temperature (550 ℃) combustion of soil in order to separate Clorg from
Clmineral that is originated not from the FDNPP accident.
From the absorbent solution, 5 ml aliquot was taken for analysis of stable chlorine by ion
chromatography. Then, appropriate amount of chlorine carrier 36Cl/Cl ≈ (5 − 8) × 10−15 was added to theabsorbent solution. Lastly, the sample solution was purified by the procedure described previously in orderto remove 36S that interferes 36Cl-AMS, and then chlorine was precipitated as AgCl [2]. The 36Cl/Cl ratio
was measured by the AMS system at UTTAC. The terminal voltage was 6.0 MV and the detected ion was
36

Cl8+. The measured ratios were normalized using the 36Cl standard (36Cl/Cl = 5.00 × 10−13) developed by

Sharma et al. [7].
Figure 2 shows the depth profiles of Clorg concentration, 36Cl/Cl, and 36Clorg concentration in 2013, 2016,
and 2017. The high ratios of 36Cl/Cl are observed for Clorg as well as for Clinorg [3]. However, the depth
profiles of 36Cl/Cl for Clorg seem to have broad peaks, while those of 36Cl/Cl for Clinorg are monotonicallydecreasing [3]. We may therefore assume that the fast isotope exchange of Clinorg started right after the
FDNPP accident and, in parallel, Clinorg was converted to Clorg. In consequence, the 36Cl/Cl ratios for Clorg
are those before fast isotope exchange of Clinorg has ended.

Fig.2. Depth profiles of Clorg concentration, 36Cl/Cl, and 36Clorg concentration in soil at Namie-machi,
Fukushima (37° 33′ 39″E, 140° 49′ 41″N) on June 12, 2013, June 17, 2016, and September 10, 2017.

References[1] Y. Miyake et al., Nucl. Instr. Meth. Phys. Res. B 361 (2015) 627.
[2] Y. Ohta et al., UTTAC Annual Report 2016 (2017) 20.
[3] Y. Ota et al., UTTAC Annual Report 2017 (2018) 19.
[4] G. Öberg et al., Applied Microbiology and Biotechnology (2002) 565.
[5] D. Bastviken et al., Geochimica et Cosmochimica Acta (2007) 3182.
[6] Y. Muramatsu et al., Quaternary Geochronology (2008) 291.
[7] P. Sharma et al., Nucl. Instr. Meth. Phys. Res. B 52 (1990) 410.

22

3.6

Distribution of 129I inventory in difficult-to-return zones in Fukushima
Prefecture

H. Yokoyama, K. Sueki, K. Sasa, T. Matsunaka1, T. Takahashi, M. Matsumura, K. Takano, Y. Ochiai,
R. Hasegawa, Y. Ota
Due to the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in March 2011, large amount ofradionuclide was released from FDNPP. In particular, the total amount of 131I (half-life: 8.01 d), 134Cs (halflife: 2.06 y) and 137Cs (half-life: 30.1 y) released into the atmosphere was estimated to be approximately 16,
1.8, and 1.5 PBq, respectively [1]. 131I is one of the harmful radionuclides released from FDNPP because of
causing thyroid cancer in children, and therefore, it is urgent to elucidate environmental dynamics of 131I.
However, it is difficult to do this by direct measurements of 131I owing to its short life. Instead, reproductionof distribution of 131I inventory employing long-lived 129I (half-life: 1.57×107 y) has been now under way,
and as one of the approaches, the weighted average of 131I/129I ratio at Fukushima on March 11, 2011 wasdetermined to be (4.02 ± 0.81) × 10−2 [2]. On the other hand, 134Cs and 137Cs remain a lot in the soil several
years after the FDNPP accident and possibly influence human health, so that we must grasp the distributionof 134Cs and 137Cs inventory. Currently, the regional distributions of deposited 131I and 129I have been reported[2-4], but the deposition near FDNPP has little been reported. Thus, we observed the deposition amounts of
129

I, 134Cs, and 137Cs in the surface soils of the vicinity of FDNPP and discussed the relation between

radioactive iodine and cesium released from FDNPP.
In this study, 44 soil samples were collected at Namie, Futaba, and Okuma, in Fukushima Prefecture.
After they were homogenized, 134Cs and 137Cs activities were measured with a Ge gamma-ray detector(IGC25190, Princeton Gamma Tech). For the homogenized soil of 0.5 g, iodine was extracted bypyrohydrolysis with 0.5 g V2O5 [5]. Iodine thus obtained was purified by solvent extraction and then it was
precipitated as AgI. The isotope ratio 129I/127I was measured by accelerator mass spectrometry (AMS). In
addition, 127I concentration in the trap solvent obtained by pyrohydrolysis was measured with the inductively
coupled plasma-mass spectrometer (ICP-MS, Agilent 8800).
As a result, the deposition amounts of 129I, 134Cs, and 137Cs in the surface soil on March 11, 2011 are
estimated to be 0.0385 − 5.11 Bq m−2, 0.0663 − 37.1 MBq m−2, and 0.0668 − 38.1 MBq m−2, respectively.
The radioactivity ratio of 129I/137Cs is (0.0603 − 4.83) × 10−6. Distributions of 129I inventory and radioactivity
ratio of 129I/137Cs are shown in Fig. 1. A positive correlation between 129I and 137Cs radioactivity
concentrations is recognized, especially in the area where the radioactive plumes passed through. For
example, in the area more than 13 km northwest of FDNPP, the correlation coefficient between 129I and 137Cs
is 0.92 and the ratio of 129I/137Cs is (2.3 ± 0.2) × 10−7. In the north-northwest of FDNPP, the correlation
coefficient is 0.98 and the ratio of 129I/137Cs is (2.7 ± 0.2) × 10−7. These ratios agree well with the calculated
values of ~ 3 × 10-7 using ORIGEN 2.2 code [6].

1Kanazawa University

23

Fig.1. (a) Distributions of 129I inventory and (b) radioactivity ratio of 129I/137Cs.
The base maps of these figures were made by Geographical Survey Institution
in Japan.

References[1] METI (Ministry of Economy, Trade and Industry in Japan), Revised Total Release of Radionuclides (inJapanese), 2011.

http://warp.da.ndl.go.jp/info:ndljp/pid/3487098/www.meti.go.jp/press/2011/10/

20111020001/20111020001.pdf[2] K. Sasa et al., UTTAC annual report 2013, p. 35[3] Y. Miyake et al., Geochemical Journal, 46 (2012) 327.
[4] Y. Muramatsu et al., Journal of Environmental Radioactivity, 139 (2015) 344.
[5] Y. Muramatsu et al., Quaternary Geochronology, 3 (2008) 291.
[6] K. Nishihara et al., JAEA-Data/Code 012-018 (2012) (in Japanese).

24

3.7

Anthropogenic iodine-129 in the Japan Sea and Okhotsk Sea during
2017−2018

T. Matsunaka1, S. Nagao1, M. Inoue1, S. Ochiai1, T. Morita2, S. Miki2, N. Honda2, T. Aramaki3, I. Kudo4,
T. Takikawa5, K. Sueki, T. Takahashi, K. Sasa
Long-term oceanographic observation revealed that warming and oxygen decrease of the Japan Sea
Bottom Water (JSBW) are responding to air temperature raise in winter [1]. Investigation of water dynamics
in the Japan Sea using a radioactive tracer is essential for elucidating the interaction between climate change
and the convection system. Recent progress in our research program using the 129I tracer is reported.
Anthropogenic 129I (T1/2 = 15.7 million years) produced from the thermal neutron fission is released
dominantly from nuclear fuel reprocessing plants in Europe. To investigate the availability of 129I as a tracerof surface circulation and vertical convection in the Japan Sea, AMS at UTTAC was used to measure thehorizontal and vertical distributions of 129I in the large area of the sea in 2017–2018. The radioactivity of
129

I dissolved in surface water in the East China Sea and the Japan Sea varied from 15.1±0.7 to 25.1±0.8

nBq L–1, and was negatively correlated with salinity (R2 = 0.94, n = 18), see Fig. 1.
The salinity dependence of the distribution has revealed that 129I dissolved in the area is controlled bymixing of water mass from the Liman Current and the Tsushima Current. Meanwhile, 129I dissolved in the
JSBW observed in the layer of 2450–3500 m of the Japan Basin in 2017 and 2018 were 4.2±0.6 nBq L–1
and 4.2±0.5 nBq L–1, shown respectively in Fig. 2, which increased by 1.2 nBq L–1 from that in 2007 [2].
Further studies using the 129I tracer is now under way.

Fig. 1. Sampling sites of surface seawater in the East China Sea, Japan Sea, and Okhotsk Sea (A). The
correlations between 129I activities in seawater and salinity (B). The linear regression lines and coefficientsof determination (R2) are shown in the correlation diagram.
1

Kanazawa University
Japan Fisheries Research and Education Agency
3 National Institute for Environmental Studies
4 Hokkaido University
5 Nagasaki University
225

Fig. 2. Vertical distributions of 129I in the Japan Basin observed in 2007 [2], 2017, and 2018.
The boundaries of the proper water and bottom water are also shown.

References[1] T. Gamo, Trends Anal. Chem. 30 (2011) 1308
[2] T. Suzuki et al., Nucl. Instr. Meth. Phys. Res. B 268 (2010) 1229

26

3.8

Performance of Iodine-129 AMS measurements at the University ofTsukuba

M. Matsumura, K. Sasa, T. Takahashi, K. Takano, Y. Ochiai, H. Yokoyama, T. Matsunaka1, K. Sueki
Improvement of accelerator mass spectrometry (AMS) at the University of Tsukuba has been
continued since its setup in 2015. This report focuses on the development of the standard referencematerials (STD) in the near future for 129I-AMS. Details of the 129I measurement conditions with the 6MV
tandem accelerator were described in the references [1, 2].
We measured 294 samples of 129I from April 2018 to March 2019, as shown in Fig. 1. The test samples
were chosen from environmental materials such as soil, rain water, sea water and coral. The 129I/127I ratioof sea water and coral samples are extremely low, on the order of 10−13. Thus it is important to keep a low
background level in 129I-AMS. Figure 2 shows the measured background values using blank samples forFig. 1. 129I samples measured by the
AMS system in fiscal 2018.

Fig. 2. 129I/127I ratios for blank samples.

the past 3 years. “Old Iodine” provided from Deepwater corporation has the extremely low background, as
low as 129I/127I ~2 × 10−14, while the machine background is estimated to be lower, i.e., 129I/127I~10−15.

However, sometimes, the measured values of 129I/127I for blank samples are ten times higher thanfor the Old Iodine. This might be mainly attributed to the memory effect, discussed previously [3].
We performed Cs irradiation to the cathode filled with Nb powder only, considering that the same Nb
powder was used for the cathode disk which results in the high 129I/127I ratio of 10−11~10−10. Aftermeasuring these samples of high 129I/127I ratios, we measured the Nb-filling sample. As shown in Figs. 3
and 4, there certainly exists the memory effect. The detector system appears to have a memory of 129I5+,
since the 129I5+ counts from the Nb-filling sample decreases with increasing the irradiation time. Even 100
minutes later, approximately 5, rather than 0, counts were detected, so that it seems difficult to completely
remove the memory effect. The enhanced background level obtained from blank samples in 2018 is likely
to be caused by this memory effect. Therefore, low-level samples must be carefully measured, i.e., not in
the same series of analysis including other samples of greatly different isotope ratios.
This work was supported in part by JSPS KAKENHI Grant Numbers 15H02340.
1

Kanazawa University

27

Fig. 3. The 129I spectra from the Nb-filling sample.

Fig. 4. Time variation of 129I counts.

References[1] K. Sasa et al., Nucl. Instr. Meth. Phys. Res. B 437 (2018) 98.
[2] M. Matsumura et al., UTTAC Annual Report 2016 (2017) 25.
[3] M. Matsumura et al., Proceedings of the 21th Symposium on The Japanese Society of Accelerator
Mass Spectrometry Research (2018), in press.

28

4.
BEAM AND ISOTOPE APPLICATIONS

4.1

Free volumes introduced by fractures of CFRP probed using positronannihilation

A. Uedono, K Sako, W. Ueno, M. Kimura1
A void formation at nanoscale and a crack initiation at micrometer scale in CFRP during a tensile test
were investigated by means of positron annihilation and X-ray computed tomography (X-CT). Free volumes
in bisphenol-A epoxy resin in CFRP were probed, and a mean diameter of free volumes at room temperature
was determined to be 0.49 nm. The crack initiation and propagation in the CFRP sample were observed byin-situ measurements of X-CT during a tensile test. For the sample after the tensile test, free volumes witha mean diameter of 0.70 nm were introduced near fractures locations. In the same locations, the density offree volumes which intrinsically existed in the polymer resins decreased. Thus, the introduction of the freevolumes was attributed to breaks in molecular chains upon fracture and a resultant agglomeration of intrinsic
free volumes in the polymer matrix.

Fig.2. Stress and strain curve for CFRP sample.
Measurements were interrupted three times for X-CT
measurements (denoted as b, c, and d). Fracture ofsample occurred at ε = 7.6%.

Fig.1. (a) illustration of CFRP sample, and (b) picturesof sample before (above) and after tensile test (below).
Positions of lifetime measurements are shown as whiteopen circles on the sample after the tensile test.

Fig.3. Reconstructed 3D images near center of sample at ε
= (a) 0%, (b) 1.0%, (c) 2.1%, (d) 3.1%, and (e) 7.6%, whichwere obtained by in-situ X-CT measurements. Positions ofdelamination and/or cracks are denoted as 1, 2, 3, and 4.
1

Institute of Materials Structure Science, KEK

29

Fig. 4. Cross section ofreconstructed images
near center of sample
with ε = 3.1% (a) andits magnified image (b).
White arrows show thedirection and stress andblack arrows showtransverse crack andvoids near the carbon
fibers, respectively.

Fig.5. Temperature dependence of third lifetime (a) andcorresponding intensity (b) for CFRP sample before
tensile test. Diameter of free volumes corresponding to τ3
is shown on right axis. Temperature gradient of τ3
increased at −40°C.

Fig.6. Positron lifetimes for CFRP sample after
tensile test. Positions of measurements (horizontalaxes) are shown in Fig. 1(b). First and second
components were associated with the annihilation of
positrons in both carbon fibers and polymer matrix.
Third and fourth components were attributed to thepick-off annihilation of o-Ps in polymer matrix.

Fig.7. Relative intensities for CFRP sample
after tensile test.

Fig.8. Schematic of free volumes and fracturesin CFRP (a) before and (b) after tensile test.

Reference[1] A. Uedono et al., Composites Part A 122 (2019) 54.

30

4.2

Preliminary micro-PIXE analysis of silicate glass particles released from
Fukushima nuclear plant

M. Kurosawa, K. Sueki, K. Sasa, S. Ishii, M. Matsumura, K. Matsuo, T. Ishii
Radioactive silicate microparticles emitted from the Fukushima Daiichi nuclear power plant (FDNPP)
have recently attracted attention as a transportation process of radioactive cesium to the naturalenvironment [1‒6]. Ono et al. [5] and Satou et al. [6] discovered a new type of radioactive silicate-glass
particles with cesium in a soil sample collected at the northwestern region of the FDNPP. Theseradioactive particles are emitted certainly from reactor 1 of the FDNPP [5, 6]. Thus, chemical
characterization of such glass particles is important to understand the formation processes and the situation
inside the reactor 1 at the nuclear accident. For these reasons, we analyzed major to trace elements in theradioactive silicate glass particles by using micro PIXE to examine the chemical compositions.
Glass-particle samples were collected by Ono et al. [5] and Satou et al. [6]. The two samples (T43 andT23) analyzed were a few hundred micrometer-sized and irregular-shaped aggregates of fused glass andglass particles with tiny solid inclusions and bubbles. The sample surfaces were polished and were coatedwith a carbon film to prevent electrostatic charging. Before the micro-PIXE analyses, major compositionsof the samples were analyzed with a scanning electron microscope equipped with an energy-dispersive
X-ray spectrometer (SEM–EDS) to determine the stopping power and X-ray attenuation factors of thesamples. Major compositions of glass matrices in the two glass samples are quite homogeneous, but small
areas including tiny inclusions consist of highconcentration of FeO or ZnO, TiO2, BaO, andTable 1. Major chemical compositions of soda-lime
glasses and glass matrices of T23 and T43.

PbO. The glass matrices agreed in chemicalcomposition with a typical soda-lime glasses(Table 1). Taking into account many bubbles in

Soda-lime glasses

T23 and T43

Float Container Sample
glass[7] glass[7][8]glass matrices*1

the glass matrices, the glass-particle samples

wt.%

could be emitted at high temperature conditions

Na2O
13.50
MgO
3.80
Al2O3
1.80
SiO2
72.60
SO3
0.20
K2O
0.00
CaO
7.90
TiO2
0.00
MnO
0.00
FeO
0.10
Total
99.90
Density*2—
Melting(°C) *3 —above melting points of soda-lime glasses (Table
1) from the FDNPP. Densities of the glass
matrices were estimated by using the equation of
Huggins and Sun [9].
PIXE analyses were performed at the 1MV
Tandetron. A 0.1 nA beam of 1.92-MeV proton
was focused to a 26.4 × 19.8 μm spot on thesample using slits and magnetic lenses. The beam
was incident normal to the sample surface, and
the X-ray measurement take-off angle was 45˚[10]. The characteristic X-rays excited by theincident beam were collected by the Si(Li)Average std (1s)
13.10
0.10
1.80
72.50
0.18
0.80
11.20
0.00
0.00
0.03
99.71
—
1063

13.40
1.70
1.20
72.50
0.30
0.40
10.60
0.00
0.00
0.00
100.10
2.507
—

10.26
3.20
3.93
74.21
0.42
0.43
7.02
0.39
0.02
0.09
99.97
2.50
—

(0.97)(0.21)(0.19)(0.73)(0.19)(0.08)(0.36)(0.17)(0.03)(0.06)*1Average chemical composition of T23 and T43 glasses
determined by SEM — EDS and the standard deviations.
*2Density(g/cm3) of soda-lime glass [8] was a measured
value and those of T23 and T43 glasses were calculated byusing the equation of Huggins and Sun [9] and the averaged
chemical composition. *3Melting temperature [7].

31X-ray-energy detector with a nominal resolution of 140 eV at 5.9 keV. We used a 55-μm-thick Mylar filter
to prevent the scattered protons from entering the detector. The total charge was determined by integrating
the target current, and all the samples were analyzed for the total charges of 0.31 μC to 0.33 μC.
Analytical points were chosen based on optical viewing using a CCD camera mounted on the microscope.
Quantification of the PIXE analyses was performed based on the model of Kurosawa et al. [10].
PIXE spectra of the glass samples, shown in Fig. 1, consist mainly of intense K X-ray peaks from Si,
Ca, Ti, Fe, and Zn. The spectra also show K X-ray peaks from trace amounts of S, Cl, K, Cr, Mn, Sr, andZr, and L X-ray peaks from Pb and Ba. X-ray intensities of Ti, Fe, Zn, Ba, and Pb depend on themeasurement points, indicating a presence of tiny solid inclusions containing these elements. L X-ray
peaks from trace Cs are not identified because of the overlapping with the intense Ti Kα peaks. Element
concentrations of the two glasses, determined by PIXE, are as follows: 22.97‒30.35 wt.% for Si,
6.10‒6.76 wt.% for Ca, 0.27‒6.40 wt.% for Ti, 0.34‒0.47 wt.% for K, 0.06‒0.74 wt.% for Zn, 0.14‒0.23
wt.% for S, 0.00‒0.23 wt.% for Ba, 0.02‒0.13
wt.% for Cl and Pb, 0.00‒0.03 wt.% for Cr, Mn,
Cu, Sr, and Zr. These contents of the major
elements agree with the SEM–EDS results (Table1). Highly volatile elements such as Cl and S
remain homogeneously in the glass samples. The
presence of the volatile elements indicates ashort-time heating at high-temperature conditions
during the formation process of the glass particles.
The glass particles can be quenched materials of
fused soda-lime glass with the minor components
melted by a flash heating (<1000 °C). Melting
experiments of the glass particles may be useful to
decode the thermal history. In addition, PIXE
measurements of K X-ray peaks from Cs by using
a 4-MeV proton beam would be suitable fordetection of Cs in Ti-rich glass materials.

Fig.1. PIXE spectra of silicate glass particles emitted
from the FDNPP [5, 6]. Upper spectrum: T23. Lower
spectrum: T47. Escape and pile-up peaks are identified asfollows: e (escape peak of Ca Kα), p (pile-up peaks of Ca
Kα+Ca Kα and Ca Kα+Ca Kβ).

References[7] Glass Technology Handbook, eds. M. Yamane[1] K. Adachi et al., Sci. Rep. 3 (2013) 2554.

et al., Asakura shoten, Tokyo, 1999.

[2] Y. Abe et al., Anal. Chem. 86 (2014) 8521.
[3] N. Yamaguchi et al., Sci. Rep. 6 (2016) 20548.

[8] P. Bingham, Glass Technol. 45 (2004) 255.

[4] T. Kogure et al., Microscopy 65 (2016) 451.

[9] M. Huggins and K. Sun, J. Amer. Ceramic.
Soc. 26 (1943) 4.

[5] T. Ono et al., Bunseki Kagaku 66 (2017) 251.

[10] M. Kurosawa et al., Nucl. Instr. Meth. Phys.

[6] Y. Satou et al., Geochem. J., 52 (2018) 137.

Res. B 266 (2008) 3633.

32

4.3

Kinetic energy measurements of 10−100 keV ions using superconducting
tunnel junction

S. Tomita, S. Shiki1, G. Fujii1, M. Ukibe1
Superconducting tunnel junction (STJ) has a structure of a thin insulator film sandwiched by two
superconducting films. The phonons excited by an impinging particle break Cooper pairs in the
superconductor, and generate quasiparticles. By applying potential difference between the two
superconductors, the quasiparticles tunnel through the insulator. The total amount of the tunneling current
is approximately proportional to the amount of generated quasiparticles, i.e. the amount of deposited energy
on the superconducting film. Therefore, STJ can be used as an energy sensitive detector. The amount ofenergy required to break a Cooper pair is on the order of ~meV, thus STJ can be used to measure kinetic
energy of keV particles to which the conventional semiconductor detector cannot be applied.
The STJ detector has been successfully used to measure X-rays and ions of keV energies [1]. In particular,
the application of the detector in combination with mass spectrometer enables us the separate measurementof ion mass m and ion charge q, while the conventional mass spectrometers can measure only m/q of ions[2]. The application of this technique to detect biomolecule ions could be quite useful to distinguisholigomers having the same m/q values. The protein molecules could have charge states of 10+ to 20+ when
an electrospray ion source is used. These ions have kinetic energies of several tens keV. On the other hand,
it is known that in the high energy range the pulse height of STJ signal deviates from the proportional
response. The mechanism for the deviation is not understood yet, therefore we plan to investigate the STJ
response of 10−100 keV carbon ion.
Experiments were performed with the 100-kV ion injector with a cesium sputtering ion source. The
negatively charged carbon ions were accelerated and injected into the STJ detector after mass selection witha dipole magnet. The detectors have a structure of Nb/Al/AlOx/Al/Nb, and mounted on a cryostat with thebase temperature of about 290 mK. The size of the detector is 100×100 μm2, and the magnetic field of 100
gauss was applied to eliminate tunneling current due to the Josephson effect. The pulse height distributionof the STJ signal is shown in Fig. 1 for the injection of 15 keV carbon ions. The peak shape has a long tailon the low energy side. This might be due to the escape of particles such as secondary electrons or sputteredparticles, and backscattering of injected ion itself, as well. In Fig. 2, the mean value of the pulse heights ofsignals from the STJ detector is shown as a function of the kinetic energy of impinged ion. For the highenergy particles, the deviation from proportional response is observed. We plan to perform a series ofmeasurements of various ions with different energies to understand the mechanism of the deviation for
detection of high energy particles.

1

National Institute of Advanced Industrial Science and Technology (AIST)

33

600

500

Counts

400

300

200

100

0
0

200

400

600

800

1000

Pulse height (arb. unit)

Pulse height (arb. unit)

Fig. 1. Pulse height distribution of STJ signal for the detection of 15 keV carbon ions.

800
750
700
650
600
550
500
450
400
350
300
250
200
150
100
50
0
0

5

10

15

20

25

Kinetic energy (keV)

Fig. 2. Mean value of the pulse heights of signals from superconducting tunnel junction
detector as a function of the kinetic energy of impinged carbon ions.

References[1] M. Ohkubo et al., IEEE Transactions on Applied Superconductivity 24 (2014) 1.
[2] S. Shiki et al., Journal of Mass Spectrometry 43 (2008) 1686.

34

4.4

3D imaging of hydrogen distribution in H-charged Al

A. Yamazaki, S. Ishii, K. Sasa, S. Tomita, H. Naramoto, M. Sataka, H. Kudo
Analysis of hydrogen in materials, particularly acquisition of three-dimensional distribution of hydrogenhas been a challenging issue since hydrogen contained as an impurity in the material affects the mechanicalproperties of the material even if the amount is small. Mainly based on the results of previous research on
the formation of focused ion beams, we developed a method to acquire the three-dimensional distributionof hydrogen using elastic recoil detection analysis (ERDA).
In transmission ERDA, a probe ion beam is incident perpendicularly on a thin film sample and the recoilhydrogen is detected on the back side of the sample. By scanning the sample with a well-focused beam,hydrogen mapping with high position resolution can be achieved. Since the energy of recoil hydrogen
depends on the depth from the surface of the sample, where hydrogen experiences a head-on collision with
the ion, the hydrogen distribution as a function of depth can be deduced. Accordingly we may obtain thethree-dimensional distribution of hydrogen in the material.
Figure 1 is a schematic diagram of the transmission ERDA method. The Al sample contains hydrogen
which was incorporated by plasma-charging. The thickness ofthe sample was adjusted to 130 μm so that the incident He canbe stopped within the sample, while the recoil hydrogen canpass through the sample. For effective detection of recoilhydrogen, 8-10 MeV He is advantageous because of the large
recoil cross section due to the nuclear elastic collision. The
sample was scanned with an 8-MeV He beam focused to a

Fig. 1. Schematic diagram of the

few-μm diameter, while measuring the energy spectrum oftransmission ERDA.

recoil hydrogen passed through the sample.
Figure 2 shows the analysis result. The analyzed area on the Al sample is 500 μm × 500 μm, where thehydrogen signals are shown in yellow for the three sliced depths of 5 μm width. These maps indicate thathydrogen aggregates and changes probably to H2 bubbles. Moreover, brightness of each yellow spot varies
with increasing the depth, reflecting the 3D shape of the aggregates.
It is notable that the member of
the UTTAC micro-beam group has
filed a patent application as ahydrogenimaging

three-dimensional
method

that

can

be

obtained with "micrometer position
resolution" and "low beam dose",
combining the ion beam focusing
technology with these research

Depth: 0−5 μm

5−10 μm

10−15 μm

Fig. 2. Distribution of plasma-charged hydrogen in Al.

results.

35

4.5

Reflection ERDA of hydrogen isotopes in DLC/Si using 15 MeV 16O ions

H. Naramoto, M. Sataka, H. Kudo, A. Yamazaki, S. Sasa
Hydrogen profiling has been one of the important element analysis issues in materials science andseveral kinds of the profiling methods have been developed based on different kinds of ion-atom interactions.
The elastic recoil process gives us a chance to detect several kinds of low Z elements simultaneously, whichis inevitable to study their migration behavior influenced with each other among the low Z elements.
In the present study, 15 MeV 16O ions were chosen to detect hydrogen isotopes simultaneously withreasonable depth resolution under the reflection ERDA mode. At this energy of oxygen ions, the interaction
between the projectile and H(D) is governed by the non-Coulombic process, which results in larger recoilcross-sections than in the Coulomb case. The relatively large cross sections given numerically by theevaluated data-set are useful for sensitive detection of relevant elements [1]. In addition, the present energy
condition of oxygen ions is also applicable to detect high Z elements with the good mass-separation under
the standard RBS process [2, 3].
For reliable reflection ERDA, it is the inevitable first step to calibrate the recoil detection angles withrespect to the incident beam direction. The recoil detection angle in the present ERDA was calibrated
referring to the transmission ERDA spectra of hydrogen from Kapton/Al under the normal incidence of 15
MeV 16O4+ ions. After the angle calibration of the detection system, the reflection ERDA with the same ion
beam was performed on DLC (160nm thick, H:D=4:1)/Si sample with a Mylar filter (14μm) for selective
stopping of reflected oxygen ions. The RBS spectra at different higher angles from the heavy elements weretaken for the energy calibration in the same detection system without a Mylar filter, keeping the otherexperimental parameters unchanged.
Figure 1 illustrates the typical changes of leading edges in the transmitted recoil hydrogen spectra from
Kapton(7.5μm)/Al(15μm) under the70

normal incidence of 15MeV 16O4+
detection

angles.

In

order

to

minimize the influence of irradiation
effects on the recoil spectra of
Kapton film, the integrated numberof incident ions was limited to be as
small as 1.5×10

14

2

particles/cm per-12.0 °

60

Recoil Yield (Counts/Ch.)

ions at non-calibrated (nominal)-8.0 °
50-4.0 °
0.0 °

40
30
20
10

spectrum, however, one can easily
see the systematic changes of leading

0
200

220

edge channels in the transmittedhydrogen recoil

spectra. In thiscalibration,

recoilthedetection

angles were scanned in the range

240

260

280

300

320

340

Channel Number (Ch.)
Fig. 1. Transmitted hydrogen recoil spectra under the normal incidenceof 15 MeV 16O4+ ions onto Kapton(7.5μm)/Al(15μm) film at nominal
detection angles.

36

from −12° to +13°.
leading edge positions in transmitted hydrogenrecoil spectra plotted against non-calibrated
detection angle with an interval of 0.2°. The realdetection angle of 0° was found at the nominal
angle of −1.06° assuming the symmetric changeof leading edge positions. This deviation of
1.06° is small compared with the previous valueof +3.13° for 8 MeV 4He on the same beam line[4]. Since the angle calibration should depend
sensitively on the beam transport conditions, it
is recommended to perform the detection angle
calibrationifdifferent

beamtransport

conditions are employed.
Figure 3 shows the reflection ERDA
spectrum at 30° from DLC(160nm thick,Leading Edge Energy of Recoil Spectra (Ch)

Figure 2 shows the symmetric change ofDetector Angle Calibration
305−1.06°

295

285

-15

275
-5
0
5
10
Recoil Detection Angle (Degree)

-10

15

Fig. 2. Recoil detection angle calibration for reflection
ERDA analysis. The positions of leading edges intransmitted hydrogen spectra are plotted against nominal
recoil detection angles under the normal incidence of 15
MeV 16O4+ ions onto Kapton(7.5μm)/Al(15μm).

H:D=4:1)/Si under the oblique incidence of
15MeV 16O4+ ions. One can see the reasonable
deuterium. This separation suggests a possibilityof hydrogen profiling in a thicker DLC film
without any peak interference. Also, one may
expect appearance of an isolated 4He signal peak

Recoil Yield (Count/Ch.)

separation of signal peaks from hydrogen andRecoil Spectrum from DLC(H:D=4:1)/Si under Oblique
Incidence of 15MeV 16O4+ (θr=30º, α=75º)

250
200
150
100
50

4

on the higher energy side if there exists He

0atoms [1]. In conclusion, it is confirmed that theemployment of oxygen ions as the analyzing
beam is effective for simultaneous hydrogenisotope profiling with limited influence ofradiation effects compared with ERDA usingmuch heavier ions.

0

1

2

3
Energy(MeV)

4

5

Fig. 3. Reflection recoil spectrum from DLC(160nm,
H:D=4:1)/Si under the oblique incidence of 15 MV 16O4+
ions (Ɵr=30º, α=75º). The peaks at higher and lower
energies correspond to deuterium and hydrogen,respectively.

References[1] E. Markina et al., Nucl. Instr. Meth. Phys. Res. B 269 (2011) 3094.
[2] M. DÖbeli et al., Nucl. Instr. Meth. Phys. Res. B 63 (1992) 68.
[3] M. Nasir Khan et al., J. Appl. Phys. 86 (1999) 2307.
[4] H. Naramoto et al., UTTAC Annual Report 2017 (2018) 48.

37

6

4.6

Development of TOF−E telescope ERDA for depth profiling of lightelements at UTTAC

Y. Sugisawa, D. Sekiba, I. Harayama
TOF–E telescope ERDA (Time-of-flight−energy telescope elastic recoil detection analysis) is a usefultechnique for quantitative depth profiling of light elements in thin films [1, 2]. In this method, the velocity
and energy of the probe particle are measured in coincidence, and their relationship allows identificationof the particle mass. In addition, high depth resolutions of several nanometers have been achieved by
TOF−E telescope ERDA [1, 3]. This technique can be applied to the analysis of thin multilayer films. We
have developed a similar system mainly for the O/N ratio determination with a depth resolution of several
nanometers. This will enable us to investigate the structure of multi-layer films, in which each layer
thickness is several tens of nanometers.
We installed the TOF−E telescope ERDA system at 1 MV Tandetron operated at UTTAC. Figure 1
shows the experimental setup of the scattering chamber and the TOF tube. We employed a pair oftime-detectors (T1 and T2), each equipped with a micro-channel plate (MCP), and a solid state detector(SSD) with a 300 mm2 sensitive area.

307

triggers, respectively, in the TOF
measurement, while SSD determines
the kinematic energy of the recoil

0°
15

beam

the two time-detectors is 706 mm. SSD

T1 : tstart

SSD for RBS

particle. T1 is placed at 307 mm fromthe sample and the distance between

SSD

30°

T1 and T2 generate start and stop706

T2 : tstop
200 mmFig. 1. Schematic view of the scattering chamber including the
TOF tube. See text for arrangement of the sample.

is placed at 1092 mm from the sample, so that the SSD’s effective sensitive area determines theacceptance solid angle 0.17 msr. in the measurement. In the present study, a 4 MeV 35Cl4+ beam with 1 × 1
mm2 size was incident on the sample at 75º from the surface normal. The recoil and backscattering angles
are 30º and 150º from the beam direction, respectively. Typically, the beam current was several nA, andthe data acquisition time for one sample was ~ 1 hour.

The newly developed system was applied toanalysis of two SiAlN films deposited on SiO2 substrates. The samples were prepared under two differentpressures, 0.3 and 0.5 Pa, of the process gas.
Figures 2 (a) and (b) show the two-dimensional histograms for the samples of low (0.3 Pa) and high(0.5 Pa) pressures, respectively, which were measured using the developed TOF−E telescope ERDA
system. The elements assigned are also indicated in Figs. 2(a) and (b). We note that Si and Al are notdistinguished. The depth profiles of elements in the films are shown in Figs. 3 (a) and (b) after
recoil-energy to depth conversion using the stopping power. The interfaces between the SiAlN films andthe SiO2 substrates are clearly seen at about 59 and 36 nm for the two samples. This implies that the depth
resolution of the newly developed system is satisfactory in the present case. Furthermore, N and O
distributions are well separated. In Fig. 3(a), only N, Si and Al are recognized in the low-pressure sample,

38

while in Fig. 3(b) O and H, other than N, Si and Al, are recognized in the high-pressure sample. These
results suggest that O and H impurities are introduced during the film deposition under the high-pressuregas. In Fig. 3(a), oxygen on the surface might be introduced by oxidation because there are no othersignals associated with oxides coming from outside. Assuming that the Si/Al ratio is 9 which is estimatedfrom the composition ratio in the sputter target, we derived the elemental composition ratios of the lowand high-pressure samples, Si : Al : N = 36.9 : 4.1 : 59 and Si : Al : N : O = 30.6 : 1.4 : 46 : 20,
respectively. The depth resolution for this measurement is about 3.3 nm, which is estimated from the full
width at half maximum of the surface oxygen peak in Fig. 3(a). As a next step, we are planning to apply
the TOF-E telescope ERDA to three-layered films.
(a)

(b)

Ar
Scattered Cl

Ar
Scattered Cl

Si&Al

Si&Al
O
N

O

N

H

Fig. 2. Two-dimension histogram of the developed TOF−E telescope ERDA taken on SiAlN films
deposited on SiO2 substrates under (a) low and (b) high pressure of the process gas.

(a)

(b)

Fig. 3. Depth profiles of elements in SiAlN films deposited on SiO2 substrates under (a) low and(b) high pressure of the process gas.

References[1] M. Chicoine et al., Nucl. Instr. Meth. Phys. Res. B 406 (2017) 112.
[2] B. Brijs et al., Microelectron. Eng. 80 (2005) 106.
[3] S. Giangrandi et al., Nucl. Instr. Meth. Phys. Res. B 261 (2007) 512.

39

4.7 Hydrogen desorption from GaN induced by thermal plasma jet annealing
J. Kikuda, D. Sekiba
Development of a method for fabricating p-type semiconductor GaN has recently attracted muchattention in the field of power electronics. While Mg is usually employed as the accepter for p-type GaN,
it is known that most of the Mg atoms included in GaN do not play their required role. One of the possible
reasons for this problem is the stable MgH formation of ion-implanted Mg and H, the latter of which is
introduced for damage suppression. In order to remove hydrogen, various post-annealing techniques after
the ion implantation have been tried. We investigated the hydrogen desorption process from GaN under
the treatment of thermal plasma jet annealing (TPJ) [1]. The remained hydrogen in the GaN sample wasquantified by RBS (Rutherford backscattering spectrometry)/ERDA (elastic recoil detection analysis). The
effects of TPJ are discussed with a one-dimensional diffusion model.
The RBS/ERDA measurements employing 2.5 MeV 4He2+ were carried out at the D-course of 1MV
Tandetron in UTTAC. The scattering and the recoil angles were 150º and 30º with respect to the beam
direction. The details of setup are described elsewhere [2]. We measured five samples: (#1) as-implanted,(#2) 10-cycle TPJ treatment, (#3) 30-cycle TPJ treatment, (#4) 50-cycle TPJ treatment and (#5)
unprocessed GaN. The conditions of ion implantation and TPJ annealing are not open at present.

Fig. 1. (a) ERDA spectra taken for the five samples #1 ~ #5. (b) The integrated ERDA yield and fitted
curves of hydrogen concentration produced from the ERDA spectra.
Figure 1(a) shows the ERDA spectra obtained for the five samples #1 ~ #5. In the spectrum for #1(as-implanted sample), we see plateau-like yields from 350 to 600 channel. These yields decrease withincreasing the TPJ annealing cycles. This behavior is more clearly seen in fig. 1(b), which shows theintegrated yield from 100 to 600 channel as a function of the TPJ annealing cycle number. The horizontal

40

blue line, by the way, indicates the hydrogen yield obtained for the unprocessed sample, hence theunprocessed GaN substrate originally contains this amount of hydrogen. By taking into account theoriginally contained hydrogen, the integrated yield is well reproduced by the exponential function as y(x)= Aexp(-ax) + C. Therefore, we see that the implanted hydrogen atoms are removed by the TPJ annealing
and the hydrogen yield converges down to the original hydrogen concentration. It seems that the originalhydrogen cannot be removed by ordinary annealing treatments.
One might have a question whether the non-equilibrium TPJ process corresponds to constanttemperature for a certain period or the temperature rise in proportion to the cycle number. For the twocases, we applied simple one-dimensional diffusion models. For the former case, we obtained a diffusion
coefficient of D = 7.9×10−9 cm2/s. This value is not far from hydrogen diffusion coefficients determined
for some typical metals that absorb hydrogen in bulk. On the other hand, we tried to plot the relation
between ln D and 1/T with some assumptions of temperature increase with increasing the TPJ annealing
cycles, as shown in Fig. 2. As a result, the hypothetic temperature increasing to 2000, 6000, and 10000 K
gives a likely activation energy ~ 0.095 eV. The assumed temperature, however, is unlikely, because themelting point of GaN is estimated as ~ 2200 K. We may therefore conclude that the TPJ cycles play a role
to keep a certain temperature, meanwhile the sample temperature could slightly increase with the TPJ
cycles.

Fig. 2. Plots of the integrated yields with some assumptions of temperature increase by the TPJ cycles.
References[1] H. Hanafusa et al., Jpn. J. Appl. Phys. 57 (2018) 06JH01.
[2] D. Sekiba et al., J. Appl. Phys. 106 (2009) 114912.

41

4.8 High-field Mössbauer measurements on Co-Ni spinel ferrites at successive
stages of synthesis
S. Sharmin, M. Kishimoto, H. Latiff, H. Yanagihara, E. Kita
Magnetic nanoparticles with a distinctive synthesis route possess tremendous potential in technologicalapplications for high-density information storage [1]. An understanding of the nature of anisotropy
interactions in magnetic materials is often of great importance, both for unravelling the physics of thesematerials and for furthering the success of any technological applications. Because the hyperfine fields areusually 40−50T, the external fields must often amount to several tesla, to resolve the spectra of the opposite
magnetic moments in ferrimagnetic materials [2].
We synthesized high-quality spinel cobalt-nickel ferrite nanoparticles by undergoing a succession ofsynthesis routes comprised of chemical co-precipitation, hydrothermal treatment, and etching inhydrochloric acid. The samples produced by chemical co-precipitation and then hydrothermal treatment are
denoted by AP and HT respectively, while the samples produced as a result of etching after hydrothermal
treatment are indicated by ET2 (HCl solution 2.0 mol/L), ET4 (4.0 mol/L),

and ET6 (6.0 mol/L).

Quite

a difference in saturation magnetization and coercivity was obtained between the HT and ET samples frommagnetization experiments, see Table 1.
Table 1. Saturation magnetization (Ms), squareness ratio (SR) andcoercivity (Hc) at room temperature.
SamplesMs (emu/g)

SR

AP

21.5

0.51

Coercivity
(Oe)
4604

HT

52

0.67

4519

ET2

60.7

0.78

5605

ET3

60.4

0.77

6281

ET4

60.5

0.77

6562

ET6

59.9

0.7

6423

Mössbauer spectroscopic experiments at room temperature and 4.2 K with no applied magnetic field
were first performed. However, from low-temperature data, it is not possible to distinguish the tetrahedral
and octahedral sites because of the overlapping of the spectra corresponding to the two sites. Since theprincipal motivation for the study was to find out the fractional occupation of Fe atoms in tetrahedral andoctahedral sites in the spinel Co-Ni ferrites, Mössbauer measurements under the application of an external
magnetic field (5 T) were carried out on both the HT and ET2 samples and the results are shown in Fig. 1.
In our configuration, the magnetic field was applied parallel to the gamma-ray direction.
With the application of the external magnetic field, the 57Fe Mössbauer spectra split into two sextets
corresponding to two anti-parallel sites. The outermost sextet corresponds to the site with the internal field

42

parallel to the applied field (resulting in alarger effective hyperfine field) and theinner sextet corresponds to the site withexternal magnetic field (resulting in asmaller effective hyperfine field).

In

usual spinel ferrites, themagnetic

moments

in

of

the

octahedral (B)sites

cationsarethealignedparallel to the magnetic field, and the ones

Transmission (arb. units)internal field antiparallel to the appliedHTin the tetrahedral (A) sites are antiparallel.
Because the direction of the hyperfine field
is opposite to that of magnetic moments,
ET2

the outer-most sextet corresponds to thetetrahedral

site

and

the

inner

one

corresponds to octahedral sites. The

-10

-5

0
Velocity (mm/s)

510observed Mössbauer spectra were fitted bythus assuming only two sites. The obtained
hyperfine parameters from the in-field
Mössbauer data are shown in Table 2. One

Fig.1. 57Fe Mössbauer spectra of HT and ET2 measured at room
temperature in the presence of 5 T magnetic field applied parallelto the γ- ray direction. Dots represent the experimental data andthe black solid curves show the best fit to the data.

can see that there is significant variation in
the area between HT and ET2 samples. At tetrahedral sites, the area is more than at octahedral sites,
indicating more Fe3+ at tetrahedral positions. However, the area decreases at the A site for the ET2 sample
in comparison to that for the HT sample, while the area increases at the B site in ET2 sample as comparedto that in the HT sample. Therefore, the process of etching leads to a significant variation of the Fe3+
distribution in the tetrahedral and octahedral sites of the Co-Ni spinel ferrite. We can conclude from the datathat etching is effective for the Fe ions to occupy more octahedral sites.
Table 2. In-field Mössbauer spectra parameters of HT and ET2 samples at room temperature.
A site (tetrahedral)
Area (%) Hhf (T) Isomer
shift(mm/s)

Line
width(mm/s)

B site (octahedral)
Area (%) Hhf (T) Isomer
shift(mm/s)

Line
width(mm/s)

HT

29.3

53.1

0.158

0.67

70.7

44.5

0.233

1.27

ET2

36.7

53.1

0.155

0.726

63.3

44.9

0.238

1.026

References[1] V. Dupuis et al., MRS Online Proceedings Library Archive 1708 (2014).
[2] W. Keune, Hyperfine Interactions 204, 13-45B (2012).

43

4.9

Mössbauer spectra of Fe-based metallo-supramolecular polymers

T. Yoshida1, M. Higuchi1
Metallo-supramolecular polymer which is formed frommetal ions and organic ligands exhibits interesting
functionalfeaturesassociated

with,

for

example,electrochromism, ionic conductivity, and luminescence. In
particular, the electrochromism is one of the promisingproperties to realize a new type of display [1]. Therefore,
many scientists have improved the performance ofelectrochromic

behaviorofmetallo-supramolecularpolymer by changing metal ions and/or organic ligands.

Fig. 1. Chemical structure of polymeric FeL.

It is required to establish the strategy of materials design
through the study of electronic states of the relevant polymers. Here, we synthesized polymeric FeL([FeL]n(OAc)2n, L = 1,4-di[[2,2’:6’,2”-terpyriidin]4’-yl]benzene) shown in Fig. 1, following the proceduredescribed elsewhere [1], and carried out Mössbauer spectroscopic analysis at UTTAC.
The measured Mössbauer spectrum of discrete Fe2+ complex (FeL’2: [Fe(L’)2](OAc)2, L’ = 2,2’:6’,2”terpyridine), shown in Fig. 2, exhibits a clear doublet indicating that the Fe ion is in low spin Fe2+. On theother hand, polymeric FeL gives an asymmetric doublet, shown in Fig. 3, which is understood in terms ofthe doublet of low spin Fe2+ superposed with the singlet of low spin Fe3+, or possibly with the singlet arisingfrom the internal magnetic field of Fe2+. These results indicate that the electronic state of polymeric FeL isfluctuated comparing to the discrete Fe complex.
3.2x106Counts

3.1

3.0

2.9

2.8

2.7

-5

-4

-3

-2

-1

0

1

2

3

4

5

Velocity (mm/s)

Fig. 2. Mössbauer spectrum of discrete
FeL’2.

Fig. 3. Mössbauer spectrum of polymeric
FeL, together with the fitted singlet anddoublet curves.

Reference[1] M. Higuchi, J. Mater. Chem. C 2 (2014) 9331.
1

National Institute for Materials Science (NIMS)

44

4.10 Influence of oxygen introduction on magnetic properties of epitaxial NdH2
thin films
D. Kutsuzawa1, Y. Hirose1, D. Sekiba
Rare earth hydrides have wide tunability of their physical properties, such as optical, electrical transport,
and magnetic properties, by adjusting the hydrogen content [1]. A remarkable feature of fluorite-type rareearth dihydrides is their magnetism. Most of them are antiferromagnetic at low temperature owing to Fermi
surface topology [2,3], while NdH2 shows ferromagnetism with Curie temperature TC of 6.8 K [4], possibly
due to large magnetoelastic coupling [3]. The TC value was suppressed by insertion of excess hydrogen(NdH2+x) at the octahedral site with concomitant decrease of carrier density [5, 6]. Based on theseobservations, it has been argued that the magnetic interaction between Nd spins is mediated by conduction
electrons (RKKY interaction). Oxygen doping is expected to modify the magnetic properties of NdH2,
because it would not only change the carrier density but also induce additional magnetic interaction between
Nd ions through spatially more extended oxygen 2p orbital than hydrogen 1s. Here, we synthesized NdD2
epitaxial thin films doped with various amounts of oxygen, NdOxDy (0.05 ≤ x ≤ 1.4) and investigated theirmagnetic properties.
NdOxDy thin films were grown on CaF2 (111) substrates by using a reactive pulsed laser deposition
technique. A Nd metal plate was ablated by a KrF excimer laser. The substrate temperature was maintained
at 250 °C. Note that deuterium, instead of hydrogen, was used to determine the hydrogen content in the film
accurately, since the deuterium content is free from the contribution from surface adsorbed species such as
water and hydrocarbon. The deuterium content y in the film was evaluated by elastic recoil detection analysis
with a 2.5 MeV 4He2+ beam (4He-ERDA) conducted with the 1 MV electrostatic tandem accelerator at
UTTAC. The oxygen content x in the film was determined by energy dispersive X-ray spectroscopy inconjunction with a scanning electron microscope, where the intensity was calibrated using a reference
sample of which x was measured by a 38.4 MeV 35Cl7+ beam (35Cl-ERDA) using the 5 MV electrostatic
tandem accelerator at the Micro Analysis Laboratory, Tandem accelerator, University of Tokyo [7]. Crystal
structures of the films were determined by X-ray diffraction (XRD) with Cu Kα1 radiation. Electricaltransport measurements were performed by the van der Pauw method. Magnetic properties were evaluatedby a superconducting quantum interference device (SQUID) magnetometer.
Figure 1(a) shows resistivity vs. temperature (ρ-T) curves of the NdOxDy films with various anion
compositions. All of the ρ-T curves showed metallic behavior (dρ/dT > 0) in the temperature range of 2 to300 K. The fluorite films (x ≤ 0.3) exhibited almost the same ρ for the entire temperature range, while ρ ofthe mixture films (x ≥ 0.6) increased with increasing x. The ρ-T curves of the oxygen-poor films (NdO0.05D2.0,
NdO0.1D2.0 and NdO0.2D2.0) show a kink around 200 K, probably due to ordering of the deuterium sublattice,as observed in NdH2+x with a variety of hydrogen contents [6]. The kink disappeared in the fluorite film with

1

The University of Tokyo45

larger x (x = 0.3) and the mixture films (x ≥0.6), implying that oxygen incorporated into
thedeuterium

suppressed

the

site

of

ordering

fluoriteof

NdD2

deuterium

sublattice. The inset of Fig. 1(a) shows ρ-Tcurves at the low temperature region (T < 20K), where ρ is normalized to the value at 20
K. All of the films show an abrupt drop of ρ
around 10 K or lower. At this temperature, we
observe in Fig. 1(b) the anomalous Hall effectwith a hysteresis loop, of which the curve
shape resembles the magnetization vs.
magnetic field loop shown in Fig. 1(c).
Therefore, we concluded that the NdOxDyfilms underwent ferromagnetic transition at
this temperature. The reduction of ρ below TC
can be attributed to suppression of electron
scattering by randomly oriented spins, asreported for NdH2+x [4].
To discuss the influence of oxygen
doping on the magnetic phase transition, we
evaluated TC from the ρ-T curves as an

Fig. 1. (a) Temperature dependence of resistivity of the NdOxDyfilms. Inset shows the resistivity in the low temperature region(T ≤ 20 K) normalized to the resistivity at 20 K. (b) Anomalous
Hall resistivity and (c) magnetization of NdO0.1D2.0 film plottedagainst the magnetic field applied perpendicular to the film
surface. (d) Temperature dependence of magnetization of the
NdO0.1D2.0 film. Dashed lines are the results of linear fitting in
the vicinity of the magnetic transition temperature. TC wasdetermined as an intersection point of these lines.

intersection of two linear lines obtained by fitting in the slightly higher and lower temperature regions. The
TC value deduced from the fluorite-NdO0.1D2.0 film was 9.6 K, which agrees well with that determined fromthe magnetization vs. temperature curve, i.e., TC = 9.9 K indicated in Fig. 1(d). The least oxygen-doped film
(NdO0.05D2.0) shows TC of 7.4 K, which is comparable to the reported values for stoichiometric NdH2 (5.6
K [8] and 6.8 K [4]). With increasing x, TC increases and reaches 10.0 K in NdO0.3D1.6, in sharp contrast to
NdH2+x, in which TC is lowered by introduction of excess hydrogen. No further increase of TC was observedin the mixture films (x ≥ 0.6).
References[1] J. N. Huiberts et al., Nature 380 (1996) 231.
[2] G. Wiesinger and G. Hilscher, in Handb. Magn. Mater. (1991) 511.
[3] S. H. Liu, Solid State Commun. 61 (1987) 89.
[4] S. Senoussi et al., J. Less Common Met. 130 (1987) 55.
[5] R. C. Heckman, J. Chem. Phys. 48 (1968) 5281.
[6] J. N. Daou et al, Philos. Mag. B 65 (1992) 127.
[7] I. Harayama et al, Nucl. Instr. Meth. Phys. Res. B 384 (2016) 61.
[8] R. L. Carlin et al., J. Appl. Phys. 2634 (1982) 53.

46

5.
BEAM IRRADIATION EFFECT

5.1

PSoC device radiation tolerance evaluation toward space application

T. Kameda, A. Nagata
PSoC (Programmable System-on-Chis) is recently attracting more attention in space application than
before because of its programming flexibility and low power consumption, however, it is necessary toevaluate its tolerance to space radiation for practical application. In this study, we choose PSoC_5LP shownin Fig. 1 and measure the SEL (Single Event Latch-up) and SEU (Single Event Upset) occurrence.

Fig. 1. PSoC_5LP used for evaluation of the radiation tolerance.

In this study, the 6MV tandem accelerator at UTTAC is used and experimental parameters for theevaluation test are shown in Table 1.
Ion
F
Cl

Table 1. Experimental parameters for the evaluation test.
LET [MeV/(mg/cm2)]
Charge state
Range in silicon [𝜇m]
7.2
14.3
3+
17.3
14.2
7+

Energy [MeV]24
48

The measurement system in this study is shown in Fig. 2. The raspberry-PI based system is used forautomatic measurement and data acquisition.

Fig. 2. Measurement system diagram.

47

Relationships obtained between SEL Cross-section and LET, and also between SEU Cross-section and
LET are shown in Figs. 3 and 4, respectively. The test result for total SEL occurrence is shown in Table 2.
Further investigation will be continued for reliability evaluation in order to conduct the conclusion.

Fig. 3. SEL cross-section vs. LET.

Fig. 4. SEU cross-section vs. LET.

Ion
Cl
F

Table 2. Total test duration and SEL occurrence.
Total test duration [min]SEL occurrence [times]
33.0
51
83.1
14

References[1] Y. Chiba, E. Asai, H. Tomioka, T. Kameda, M. Sataka, JAEA-Review 2013-057/p.73, 2014-03.
[2] Y. Chiba, E. Asai, H. Tomioka, R. Shimazu, T. Kameda, JAEA-Review 2013-059/p.13, 2014-03.

48

6.
LIST OF PUBLICATIONS AND PRESENTATIONS

6.1

Journals

ACCELERATOR AND RELATED FACILITIES
1.

Kimikazu Sasa, Tsutomu Takahashi, Tetsuya Matsunaka, Seiji Hosoya, Masumi Matsumura, Hongtao
Shen, Maki Honda, Kenta Takano, Yuta Ochiai, Aya Sakaguchi, Keisuke Sueki, Mark Stodola, andMark Sundquist, “The 6 MV multi-nuclide AMS system at the University of Tsukuba, Japan: First
performance report”, Nuclear Instruments and Methods in Physics Research B 437 (2018) 98-102.
[DOI: 10.1016/j.nimb.2018.09.011]

NUCLEAR AND ATOMIC PHYSICS

1.

S. Iguchi, T. Moriguchi, M. Yamazaki, Y. Hori, K. Koshino, K. Toyoda, J. Teuho, S. Shimochi, Y.
Terakawa, T. Fukuda, J. Takahashi, J. Nakagawara, S. Kanaya, H. Iida, “System evaluation of
automated production and inhalation of 15O-labeled gaseous radiopharmaceuticals for the rapid 15Ooxygen PET examinations”, European Journal of Nuclear Medicine and Molecular Imaging, 5 (2018)37-58.

2.

T. Moriguchi, A. Ozawa, Y. Yamato, S. Suzuki, M. Amano, D. Kamioka, D. Nagae, Y. Abe, ”Lambshift Polarized ion Source at UTTAC”, Proceeding of Science(PSTP2017) 018 (7 pages) (2018).

3.

Y. Ito, P. Schury, M. Wada, F. Arai, H. Haba, Y. Hirayama, S. Ishizawa, D. Kaji, S. Kimura, H. Koura,
M. MacCormick, H. Miyatake, J. Y. Moon, K. Morimoto, K. Morita, M. Mukai, I. Murray, T. Niwase,
K. Okada, A. Ozawa, M. Rosenbusch, A. Takamine, T. Tanaka, Y. X. Watanabe, H. Wollnik, andS. Yamaki, “First Direct Mass Measurements of Nuclides around Z=100 with a Multireflection Timeof-Flight Mass Spectrograph”, Phys. Rev. Lett. 120 (2018) 152501.

4.

D. T. Tran, H. J. Ong, G. Hagen, T. D. Morris, N. Aoi, T. Suzuki, Y. Kanada-En’yo, L. S. Geng,
S. Terashima, I. Tanihata, T. T. Nguyen, Y. Ayyad, P. Y. Chan, M. Fukuda, H. Geissel, M. N. Harakeh,
T. Hashimoto, T. H. Hoang, E. Ideguchi, A. Inoue, G. R. Jansen, R. Kanungo, T. Kawabata,L. H. Khiem, W. P. Lin, K. Matsuta, M. Mihara, S. Momota, D. Nagae, N. D. Nguyen, D. Nishimura,
T. Otsuka, A. Ozawa, P. P. Ren, H. Sakaguchi, C. Scheidenberger, J. Tanaka, M. Takechi, R. Wada,
and T. Yamamoto, “Evidence for prevalent Z = 6 magic number in neutron-rich carbon isotopes”,
Nature communications 9 (2018) 1594.

5.

C. Y. Fu, Y. H. Zhang, X. H. Zhou, M. Wang, Yu. A. Litvinov, K. Blaum, H. S. Xu, X. Xu, P. Shuai,
Y. H. Lam, R. J. Chen, X. L. Yan, T. Bao, X. C. Chen, H. Chen, J. J. He, S. Kubono, D. W. Liu,
R. S. Mao, X. W. Ma, M. Z. Sun, X. L. Tu, Y. M. Xing, P. Zhang, Q. Zeng, X. Zhou, W. L. Zhan,

50

S. Litvinov, G. Audi, T. Uesaka, Y. Yamaguchi, T. Yamaguchi, A. Ozawa, B. H. Sun, Y. Sun, andF. R. Xu, “Masses of the Tz = -3/2 nuclei 27P and 29S”, Phys. Rev. C 98 (2018) 014315.
6.

Y. H. Zhang, P. Zhang, X. H. Zhou, M. Wang, Yu. A. Litvinov, H. S. Xu, X. Xu, P. Shuai, Y. H. Lam,
R. J. Chen, X. L. Yan, T. Bao, X. C. Chen, H. Chen, C. Y. Fu, J. J. He, S. Kubono, D. W. Liu,
R. S. Mao, X. W. Ma, M. Z. Sun, X. L. Tu, Y. M. Xing, Q. Zeng, X. Zhou, W. L. Zhan, S. Litvinov,
K. Blaum, G. Audi, T. Uesaka, Y. Yamaguchi, T. Yamaguchi, A. Ozawa, B. H. Sun, Y. Sun, andF. R. Xu, “Isochronous mass measurements of Tz = -1 fp-shell nuclei from projectile fragmentation of58

7.

Ni”, Phys. Rev. C 98 (2018) 014319.

Y. M. Xing, K. A. Li, Y. H. Zhang, X. H. Zhou, M. Wang, Yu. A. Litvinov, K. Blaum, S. Wanajo,
S. Kubono, G. Martinez-Pinedo, A. Sieverding, R. J. Chen, P. Shuai, C. Y. Fu, X. L. Yan, W. J. Huang,
X. Xu, X. D. Tang, H. S. Xu, T. Bao, X. C. Chen, B. S. Gao, J. J. He, Y. H. Lam, H. F. Li, J. H. Liu,
X. W. Ma, R. S. Mao, M. Si, M. Z. Sun, X. L. Tu, Q. Wang, J. C. Yang, Y. J. Yuan, Q. Zeng, P. Zhang,
X. Zhou, W. L. Zhan, S. Litvinov, G. Audi, T. Uesaka, Y. Yamaguchi, T. Yamaguchi, A. Ozawa,
C. Frohlich, T. Rauscher, F.-K. Thielemann, B. H. Sun, Y. Sun, A. C. Dai, and F. R. Xu, “Massmeasurements of neutron-deficient Y, Zr, and Nb isotopes and their impact on rp and νp
nucleosynthesis processes”, Phys. Lett. B 781 (2018) 358.

8.

M. Rosenbusch, Y. Ito, P. Schury, M. Wada, D. Kaji, K. Morimoto, H. Haba, S. Kimura, H. Koura,
M. MacCormick, H. Miyatake, J.Y. Moon, K. Morita, I. Murray, T. Niwase, A. Ozawa, M. Reponen,
A. Takamine, T. Tanaka, and H. Wollnik, “New mass anchor points for neutron-deficient heavy nuclei
from direct mass measurements of radium and actinium isotopes”, Phys. Rev. C 97 (2018) 064306.

ACCELERATOR MASS SPECTROMETRY
1. Tetsuya Matsunaka, Kimikazu Sasa, Tsutomu Takahashi, Seiji Hosoya, Masumi Matsumura,
Yukihiko Satou, Shen Hongtao, and Keisuke Sueki, “Radiocarbon variations in tree rings since 1960
near the Tokai nuclear facility, Japan”, Nuclear Instruments and Methods in Physics Research B 439 15(2019) 64-69. [DOI: 10.1016/j.nimb.2018.12.009]
2. Tetsuya Matsunaka, Kimikazu Sasa, Seiji Hosoya, Shen Hongtao, Tsutomu Takahashi,
Masumi Matsumura, and Keisuke Sueki, “Radiocarbon measurement using a gas/solid hybrid ion source
and an automated sample preparation system at the University of Tsukuba”, Nuclear Instruments andMethods in Physics Research B 455 (2019) 204-208. [DOI:10.1016/j.nimb.2018.11.042]
3. Aya Sakaguchi, Rui Inaba, Kimikazu Sasa, Tetsuya Matsunaka, Seiji Hosoya, Tsutomu Takahashi, Maki
Honda, Hiroya Yamano, Keiichi Sasaki, Shinya Yamasaki, Tsuyoshi Watanabe, and Keisuke Sueki,

51

“Reconstruction of anthropogenic 129I temporal variation in the Japan Sea using a coral core sample”,
Marine Environmental Research 142 (2018) 91-99. [DOI: 10.1016/j.marenvres.2018.09.003]
4. Seiji Hosoya, Kimikazu Sasa, Tsutomu Takahashi, Tetsuya Matsunaka, Masumi Matsumura, Hongtao
Shen, Yuki Ota, Kenta Takano, Yuta Ochiai, and Keisuke Suekia, “Isobar suppression for 36Cl
accelerator mass spectrometry at the University of Tsukuba”, Nuclear Instruments and Methods inPhysics Research B 438 (2018) 131-135. [DOI: 10.1016/j.nimb.2018.07.001]
5. Michio Murakami, Takao Nirasawa, Takao Yoshikane, Keisuke Sueki, Kimikazu Sasa, and Kei
Yoshimura, “Estimation of dietary intake of radionuclides and effectiveness of regulation after the
Fukushima accident and in virtual nuclear power plant accident scenarios”, International Journal ofEnvironmental Research and Public Health 15(8) (2018) 1589. [DOI:10.3390/ijerph15081589]

BEAM AND ISOTOPE APPLICATIONS
1. A. Uedono, K. Sako, W. Ueno, and M. Kimur, “Free volumes introduced by fractures of CFRP probed
using positron annihilation”, Composites A 122 (2019) 54-58.
[DOI:10.1016/j.compoistesa.2019.04.020]
2. M. Sumiya, K. Fukuda, S. Takashima, S. Ueda, T. Onuma, T. Yamaguchi, T. Honda, and A. Uedono,“Structural disorder and in-gap states of Mg-implanted GaN films evaluated by photothermal deflection
spectroscopy”, J. Cryst. Growth. 511 (2019) 15-18. [DOI: 10.1016/j.jcrysgro.2019.01.021]
3. Y. Sato, S. Shibata, A. Uedono, K. Urabe, and K. Eriguchi, “Characterization of the distribution of
defects introduced by plasma exposure in Si substrate”, J. Vac. Sci. Technol. A 37 (2019) 011304(1-5).
[DOI: 10.1116/1.5048027]
4. S. Iwashita, K. Denpoh, M. Kagaya, T. Kikuchi, N. Noro, T. Hasegawa, T. Moriya, and A. Uedono, “Ionenergy control and its applicability to plasma enhanced atomic layer deposition for synthesizing titanium
dioxide films”, Thin Solid Films 660 (2018) 865-870. [DOI: 10.1016/j.tsf.2018.03.001]
5. P. Rajesh, S. Sellaiyan, A. Uedono, T. Arun, and R. Justin Joseyphus, “Positron Annihilation Studies on
Chemically Synthesized FeCo Alloy”, Sci. Reports 8 (2018) 9764(1-9). [DOI: 10.1038/s41598-01827949-2]
6. S. F. Chichibu, A. Uedono, K. Kojima, H. Ikeda, K. Fujito, S. Takashima, M. Edo, K. Ueno, and S.
Ishibashi, “The origins and properties of intrinsic nonradiative recombination centers in wide bandgap
GaN and AlGaN”, J. Appl. Phys. 123 (2018) 161413(1-13). [DOI: 10.1063/1.5012994]

52

7. K. Koike, M. Yano, S. Gonda, A. Uedono, S. Ishibashi, K. Kojima, and S. F. Chichibu, “Polaritydependence of the defect formation in c-axis oriented ZnO by the irradiation of an 8 MeV proton beam”,
J. Appl. Phys. 123 (2018) 161562(1-6). [DOI: 10.1063/1.5010704]
8. A. Uedono, T. Nabatame, W. Egger, T. Koschine, C. Hugenschmidt, M. Dickmann, M. Sumiya, and
S. Ishibashi, “Vacancy-type defects in Al2O3/GaN structure probed by monoenergetic positron beams”,
J. Appl. Phys. 123 (2018) 155302(1-8). [DOI: 10.1063/1.5026831]
9. S. Iwashita, T. Moriya, T. Kikuchi, M. Kagaya, N. Noro, T. Hasegawa, and A. Uedono, “Effect of ionenergies on the film properties of titanium dioxides synthesized via plasma enhanced atomic layer
deposition”, J. Vac. Sci. Technol. A 36 (2018) 021515(1-8). [DOI: 10.1116/1.5001552]
10. H. Okumura, S. Suihkonen, J. Lemettinen, A. Uedono, Y. Zhang, D. Piedra, and T. Palacios, “AlN metalsemiconductor field-effect transistors using Si-ion implantation”, Jpn. J. Appl. Phys. 57 (2018)
04FR11(1-5). [DOI: 10.7567/JJAP.57.04FR11]
11. A. Uedono, S. Takashima, M. Edo, K. Ueno, H. Matsuyama, W. Egger, T. Koschine, C. Hugenschmidt,
M. Dickmann, K. Kojima, S. F. Chichibu, and S. Ishibashi, “Carrier trapping by vacancy-type defects
in Mg-implanted GaN studied using monoenergetic positron beams”, Phys. Stat. Sol. B255 (2018)
1700521(1-9). [DOI: 10.1002/pssb.201700521]
12. K. Shima, H. Iguchi, T. Narita, K. Kataoka, K. Kojima, A. Uedono, and S. F. Chichibu, “Roomtemperature photoluminescence lifetime for the near-band-edge emission of (000-1) p-type GaN
fabricated by sequential ion-implantation of Mg and H”, Appl. Phys. Lett. 113 (2018) 191901.
[DOI:10.1063/1.5050967]
13. S. F. Chichibu, K. Shima, K. Kojima, S. Takashima, M. Edo, K. Ueno, S. Ishibashi, and, A. Uedono,“Large electron capture-cross-section of the major nonradiative recombination centers in Mg-doped
GaN epilayers grown on a GaN substrate”, Appl. Phys. Lett. 112 (2018) 211908(1-5). [DOI:
10.1063/1.5030645]
14. A. Uedono, T. Yamada, T. Hosoi, W. Egger, T. Koschine, C. Hugenschmidt, M. Dickmann, and H.
Watanabe, “Annealing behavior of open spaces in AlON films studied by monoenergetic positron
beams”, Appl. Phys. Lett. 112 (2018) 182103(1-4). [DOI: 10.1063/1.5027257]
15. M. Sumiya, S. Ueda, K. Fukuda, Y. Asai, Y. Cho, L. Sang, A. Uedono, T. Sekiguchi, T. Onuma, and T.
Honda, “Valence band edge tail states and band gap defect levels of GaN bulk and InxGa1−xN films
detected by hard X-ray photoemission and photothermal deflection spectroscopy”, APEX 11 (2018)
021002(1-4). [DOI: 10.7567/APEX.11.021002]

53

16. A. Uedono, T. Tanaka, N. Ito, K. Nakahara, W. Egger, C. Hugenschmidt, S. Ishibashi, and M. Sumiya,“Vacancy-Type Defects and Their Carrier Trapping Properties in GaN Studied by Monoenergetic
Positron Beams”, ECS Transactions, 86 (2018) 149-160. [DOI: 10.1149/08610.0149]
17. 上殿明良，“陽電子消滅による空孔型欠陥の評価”，New Diamond 34 (2018) 49-52.
18. Y. Shiina, R. Kinoshita, S. Funada, M. Matsuda, M. Imai, K. Kawatsura, M. Sataka, K. Sasa, andS. Tomita, “Measurement of Auger electrons emitted through Coster-Kronig transitions underirradiation of fast C2+ ions”, Nuclear Instruments and Methods in Physics Research B (2019) in press.
[DOI: 10.1016/j.nimb.2018.10.041]
19. Akiyoshi Yamazaki, Hiroshi Naramoto, Kimikazu Sasa, Satoshi Ishii, Shigeo Tomita, Masao Sataka,
Hiroshi Kudo, Masataka Ohkubo, and Akira Uedono, “Two-dimensional mapping of hydrogen andother elements in materials with microbeam-based transmission ERDA and PIXE”, Nuclear Instruments
and Methods in Physics Research B, (2019) in press. [DOI: 10.1016/j.nimb.2018.10.015]
20. Y. Hase, K. Satoh, A. Chiba, Y. Hirano, S. Tomita, Y. Saito, and K. Narumi, "Experimental Study on
the Biological Effect of Cluster Ion Beams in Bacillus subtilis Spores", Quantum Beam Science 3 (2019)8.
21. D. Kutsuzawa, Y. Hirose, A. Chikamatsu, S. Nakao, Y. Watahiki, I. Harayama, D. Sekiba, andT. Hasegawa, “Strain-enhanced topotactic hydrogen substitution for oxygen in SrTiO3 epitaxial thinfilm”, Applied Phys. Lett. 113 (2018) 253104.
22. A. Suzuki, Y. Hirose, T. Nakagawa, S. Fujiwara, S. Nakao, Y. Matsuo, I. Harayama, D. Sekiba, andT. Hasegawa, “Enhanced electrical conduction in anatase TaON via soft chemical lithium insertion
toward electronis application”, ACS Applied Nano Materials 1 (2018) 3981-3985.
23. D. Sekiba, T. Tamura, I. Harayama, Y. Watahiki, S. Ishii, K. Ozeki, and N. Fukata, “Development ofhigh-resolution ERDA with double MCP system and determination of detection limit for H and D”,
Nuclear Instruments and Methods in Physics Research Section B 430 (2018) 6-10.

54

6.2
1.

Reviews and books
加速器ハンドブック（丸善出版）
日本加速器学会 編（神谷2018 年 4 月刊行
執筆

笹

編纂委員

笹 公和

ISBN 978-4-621-08901-9

7 章 2 静電加速器 P111-114、15 章 加速器質量分析 P448-449

総ページ数
2.

幸秀 編集委員長）

571.

公和，加速器質量分析法（AMS）による極微量放射性核種の高感度分析手法の開発，放射化分析研究会誌「放射化分析」 No.32, 19-22，2018 年 12 月.

6.3
1.

Poster or oral presentations at academic meetings
A. Uedono, T. Tanaka, N. Ito, K. Nakahara, W. Egger, C. Hugenschmidt, S. Ishibashi, and M. Sumiya,“Vacancy-Type Defects and Their Carrier Trapping Properties in GaN Studied by Monoenergetic
Positron Beams”, Electro Chemical Soc. and Americas Int. Meeting Electrochem. Solis state Science,
Cancun, Mexico, 2nd October 2018. (Invited)2.

A. Uedono, W. Egger, C. Hugenschmidt, and S. Ishibashi, “Carrier Trapping and Detrapping Processes
in Wide Bandgap Semiconductors Studied by Positron Annihilation”, Int. Conf. Positron Annihilation,
Orland, USA, 19th August 2018. (Invited)

3.

上殿明良，M. M. Islam，櫻井岳暁，秋本克洋，“陽電子消滅による CIGS 薄膜中の空孔型欠陥の検出”，第 79 回応用物理学会秋季学術講演会，名古屋国際会議場，名古屋，2018 年 9月 18 日．（招待講演）

4.

上殿明良，“学術界における量子ビーム利用－陽電子消滅法を例に－”，第 1 回量子ビームク
ラブ研究会，産総研，つくば，2018 年 7 月 27 日．
（招待講演）

5.

上殿明良，“陽電子消滅法による p-GaN エピ層,イオン注入層の点欠陥評価”，第 149 回結晶工学分科会研究会，名古屋大学，名古屋，2018 年 6 月 15 日.（招待講演）

6.

K.Sasa, “New System Setup of the 6MV Pelletron Tandem Accelerator at the Univ. of Tsukuba”, 51stSymp. of North East Accel. Personnel, SNEAP2018, University of Wisconsin, Madison, USA,
September 23-27, 2018. (Invited)7.

Shigeo Tomita, “Transport of convoy electrons in solid under fast molecular ion penetration”, SHIMICACS 2018, Caen, France, July 1-6, 2018. (Invited)

55

8.

笹 公和，“フェムト同位体分析のための加速器質量分析システムの開発”，日本質量分析学会・日本プロテオーム学会 2018年合同大会，ホテル阪急エキスポパーク 大阪, 2018年5月1518日. （招待講演）

9.

笹 公和, “難測定核種の加速器質量分析法による高感度検出手法の開発“, 第79回応用物理学会秋季学術講演会, 名古屋国際会議場, 名古屋, 2018年9月18-21日. （招待講演）

10. 笹 公和, 高橋 努, 松村万寿美, 高野健太, 落合悠太, 太田祐貴, 細谷青児, 本多真紀,
松中哲也, 坂口 綾, 末木啓介, “筑波大学6 MV タンデム加速器質量分析装置における多核種AMSの技術開発”, 第21回AMS シンポジウム，日本大学文理学部 百周年記念館, 東京,
2018年12月17-18日. （基調講演）
11. 笹公和，“最近の加速器質量分析法の現状について”，第 57 回核化学夏の学校，旅館横倉，

長野, 2018 年 8 月 26-28 日.（招待講演）
12. 森口哲朗、“核物理利用者（不安定核・軽イオン）から見た教育訓練の現状と課題”, 大型加速器施設の利用に関する放射線業務従事者訓練のあり方に関するワークショップ –法令改正に向けて–, 大阪大学核物理研究センター, 大阪, 2018 年 6 月 21-22 日.（招待講演）
13. A. Ozawa, “Mass measurements in Rare-RI Ring in RIBF”, Workshop on “Physics at HIAF HighEnergy Beam Lines”, Beihang University, Peking, P. R. China, December 13-15, 2018. (Invited)
14. S. Ishibashi, A. Uedono, H. Kino, T. Miyake, and K. Terakura, “Correlation between local structuresand positron annihilation parameters for vacancy clusters in nitride semiconductor alloys”, CSW2019,
Tokyo, Japan, 16th January 2019.
15. S. F. Chichibu, K. Shima, K. Kojima, S. Takashima, K. Ueno, M. Edo, H. Iguchi, T. Narita, K. Kataoka,
S. Ishibashi, and A. Uedono, “Room-temperature photoluminescence lifetime for the near-band-edge
emission of epitaxial and ion-implanted Mg-doped GaN on GaN structures”, Int. Workshop on Nitride
Semiconductor 2018, Kanazawa, Japan, 13rd November 2018.
16. K. Fukuda, Y. Asai, L. Sang, A. Yoshigoe, A. Uedono, T. Onuma, T. Yamaguchi, T. Honda, and M.
Sumiya, “Evaluation of Al2O3/n-, p-GaN samples by photothermal deflection spectroscopy”, Int.
Workshop on Nitride Semiconductor 2018, Kanazawa, Japan, 13rd November 2018.
17. Y. Asai, A. Yoshigoe, M. Sumita, A. Uedono, and M. Sumiya, “Study of the dependence of GaN surface
oxidation on the crystalline plane by in-situ XPS during O2 molecular beam irradiation”, Int. Workshop
on Nitride Semiconductor 2018, Kanazawa, Japan, 13rd November 2018.
18. A. Uedono, K. Sakou, and W. Ueno, “Free volume properties in epoxy resins for CFRP probed bypositron annihilation”, 4th Symposium on Innovative Measurement and Analysis for Structural

56

Materials, Tokyo Headquarters (Science Plaza) JST, Tokyo, Japan, 13rd November 2018.
19. A. Yamazaki, K. Sasa, S. Ishii, S. Tomita, H. Naramoto, M. Sataka, H. Kudo, G. Itoh, A. Hashimoto,
A. Yousefi, A. Uedono, and M. Ohkubo, “Three-Dimensional Imaging of Hydrogen in Structural
Materials by Transmission ERDA”, 4th Symposium on Innovative Measurement and Analysis for
Structural Materials, Tokyo Headquarters (Science Plaza) JST, Tokyo, Japan, 13rd November 2018.
20. K. Sakou, W. Ueno, A. Uedono, T. Ishii, Y. Takeichi, and M. Kimura, “Free volume in CFRP after
tensile test probed by positron annihilation”, 4th Symposium on Innovative Measurement and Analysis
for Structural Materials, Tokyo Headquarters (Science Plaza) JST, Tokyo, Japan, 13rd November 2018.
21. W. Ueno, K. Sakou, A. Uedono, Y. Taniguchi, and K. Hayashi, “Temperature dependence of freevolumes in bisphenol A with carbon fiber studied by positron lifetime spectroscopy”, 4th Symposiumon Innovative Measurement and Analysis for Structural Materials, Tokyo Headquarters (Science Plaza)JST, Tokyo, Japan, 13rd November 2018.
22. S. Iwashita, T Moriya, K. Denpoh, and A. Uedono, “Ion energy control in capacitively coupleddischarges for PEALD processes”, 2nd Asia-Pacific Conf. Plasma Physics, Kanazawa, Japan, 12nd
November 2018.
23. K. Yuge, T. Nabatame, Y. Irokawa, A. Ohi, N. Ikeda, A. Uedono, L. Sang, Y. Koide, and T. Ohishi,“Analysis of deep traps at Al2O3/n-GaN interface using photo-assisted C-V measurement”, 2018 Int.
Conf. Solid State Devices and Materials, The Univ. Tokyo, Tokyo, Japan, 10th September 2018.
24. M. Sumiya, K. Fukuda, S. Takashima, T. Yamaguchi, T. Onuma, T. Honda, and A. Uedono, “Structural
disorder and in-gap states of Mg-implanted GaN ﬁlms evaluated by photothermal deﬂection
spectroscopy”, 19TH Int. Conf. Metalorganic Vapor Phase Epitaxy, Nara Kasugano Int. Forum, Nara,
Japan, 3rd June 2018.
25. A. Uedono, S. Armini, R. Krause-Rehberg, and A. Wagner, “Characterization of porous low-k dielectricfilms by using positron annihilation”, Japan Science Days, Rule University Bochum, Bochum,
Germany, 5th July 2018.
26. A. Uedono, S. Takashima, M. Edo, K. Ueno, H. Matsuyama, W. Egger, T. Koschine, C. Hugenschmidt,
M. Dickmann, K. Kojima, S. Chichibu, and S. Ishibashi,”Carrier Trapping Properties of Defects in Mgimplanted GaN Probed by Monoenergetic Positron Beams”, 45th Int. Sym. Compound Semiconductors,
30th Int. Conf. Indium Phosphide and Related Materials, Compound Semiconductor Week 2018,
Boston, USA, 30th April 2018.

57

27. Hidetsugu Tsuchida, Noriko Nitta, Shigeo Tomita, Kimikazu Sasa, Koichi Hirata, Hiromi Shibata,
Yoichi Saitoh, Kazumasa Narumi, Atsuya Chiba, Keisuke Yamada, Yoshimi Hirano, and Yasushi
Hoshino, “Formation of nano-porous surface structures by fast C60 beam bombardments”, 10th
International Symposium on Swift Heavy ions in Matter & 28th International Symposium on Atomic
Collisions in solids, SHIM-ICACS Caen, France, July 1-6, 2018.
28. Shigeo Tomita, Yoko Shiina, Ryo Kinoshita, Makoto Imai, Kiyoshi Kawatsura, Makoto Matsuda,
Kimikazu Sasa, and Masao Sataka, “Transport of convoy electrons in solids under fast molecular ion
penetration”, 10th International Symposium on Swift Heavy ions in Matter & 28th International
Symposium on Atomic Collisions in solids, SHIM-ICACS Caen, France, July 1-6, 2018. (Invited)
29. Tetsuya Matsunaka, Kimikazu Sasa, Tsutomu Takahashi, Keisuke Sueki, and Hiroyuki Matsuzaki.
“Pre- and post-accident C-14 levels in tree rings within 25 km of the Fukushima Dai-ichi Nuclear
Nuclear Power Plant”, The 23rd International Radiocarbon Conference (RADIOCARBON2018),
Trondheim, Norway, June 7-22, 2018.
30. Kimikazu Sasa, Tetsuya Matsunaka, Tsutomu Takahashi, Seiji Hosoya, and Keisuke Sueki .
“Performance of the New Tsukuba 6 MV AMS Facility for Radiocarbon Dating”, The 23rd
International Radiocarbon Conference (RADIOCARBON2018), Trondheim, Norway, June 7-22,
2018.
31. Kimikazu Sasa, Akiyoshi Yamazaki, Shigeo Tomita, Satoshi Ishii, Hiroshi Naramoto, Masao Sataka,
Hiroshi Kudo, Akira Uedono, and Masataka Ohkubo, “Accelerator Facilities for Ion Beam Analysisof Structural Materials”, The 4th Symposium on Innovative measurement and analysis for structural
materials (SIP-IMASM 2018), Tokyo Headquarters (Science Plaza), Japan Science and Technology
Agency (JST), Tokyo, Japan, November 13-15, 2018.
32. Y. Shiina, S. Tomita, R. Kinoshita, M. Imai, K. Kawatsura, M. Matsuda, K. Sasa, and M. Sataka,“Coster-Kronig transition of fast cluster ions studied by zero-degree electron specctroscopy”, SHIMICACS 2018, Caen, France, July 1-6, 2018.
33. Akiyoshi Yamazaki, Kimikazu Sasa, Satoshi Ishii, Shigeo Tomita, Hiroshi Naramoto, Masao Sataka,
Hiroshi Kudo, Toshihito Ohmi, Go Ozeki, A. Toshimitsu Yokobori, Jr. , Goroh Itoh, Akira Uedono,
and Masataka Ohkubo, “Direct Detection and Mapping of Hydrogen in Structural Materials Using
Ion Microbeams”, The 4th Symposium on Innovative measurement and analysis for structural
materials (SIP-IMASM 2018), Tokyo Headquarters (Science Plaza), Japan Science and Technology
Agency (JST), Tokyo, Japan, November 13-15, 2018.
34. T. Moriguchi, “Reaction cross-section measurement with a proton target”, The workshop on "Proton
and Neutron Densities and Radii in Nuclei and Related Topics", Beihang University, Peking, China,
December 17-19, 2018.
35. M. Mukai, “Development of a multi-segmented proportional gas counter for beta-decay spectroscopy
at KISS” EMIS2018, CERN, September 16-21, 2018.

58

36. D. Kamioka, “Developments of time-of-flight detector for mass measurements with the Rare-RI
Ring”, Fifth Joint Meeting of the Nuclear Physics Division of the American Physics Society and the
Physical Society of Japan, HAWII 2018, Hilton Waikoloa, Hawaii, USA, Octorber 23-27 2018.
37. 上殿明良，高島信也，江戸雅晴，上野勝典，松山秀昭，W. Egger，T. Koschine，C. Hugenschmidt，
M. Dickmann，小島一信，秩父重英，石橋章司，”陽電子を用いたイオン注入 GaN の空孔型欠陥の評価”，SIP 次世代パワーエレクトロニクス公開シンポジウム，東京ガーデンテラス紀尾
井町, 東京，2019 年 3 月 29 日．
38. 高島信也，上野勝典，田中亮，松山秀昭，江戸雅晴，嶋紘平，小島一信，秩父重英，

上殿明良，“容量測定を用いた p-GaN エピへの低濃度 Mg 注入と共注入影響の評価”，第 66
回応用物理学会春季学術講演会，東工大，東京，2019 年 3 月 11 日．
39. 秩父重英，嶋紘平，井口紘子，成田哲生，片岡恵太，小島一信，上殿明良，“注入深さ･極性面の異なる Mg イオン注入 GaN のフォトルミネッセンス”，第 66 回応用物理学会春季学術講演会，東工大，東京，2019 年 3 月 11 日．
40. 秩父重英，嶋紘平，小島一信，高島信也，上野勝典，江戸雅晴，井口紘子，成田哲生，片岡恵太，石橋章司，上殿明良，“エピタキシャル成長およびイオン注入 Mg 添加 GaN 中の非輻射再結合中心”，第 216 回研究集会

シリコンテクノロジー分科会，大阪大学中之島セン

ター, 大阪，2019 年 2 月 28 日．
41. 山崎明義, 笹公和, 石井聡, 冨田成夫, 楢本洋, 左高正雄, 工藤

博, 伊藤吾朗,

橋本 明, Afshin Yousefi, 大見敏仁，尾関郷，横堀壽光，上殿明良，大久保雅隆，“集束イオ

ンビームを用いた構造材料中の水素分析～手法と測定例～”， 第４回革新的構造材料 先

端計測拠点

国際会議・国際連携会議，科学技術振興機構 東京本部（サイエンスプラザ），

東京，2018 年 11 月 13 日．
42. 秩父重英，小島一信，小池一歩，矢野満明，權田俊一，石橋章司，上殿明良，”高純度 ZnO 中の SRH 型非輻射再結合中心の起源と捕獲断面積”，第 79 回応用物理学会秋季学術講演会，
名古屋国際会議場，名古屋，2018 年 9 月 20 日．
43. 松木伸行，松井卓矢，満汐孝治，ブライアン オローク，大島永康，上殿明良，”a-Si:H/c-Si ヘ
テロ界面近傍のボイド構造解析 –a-Si:H 中の陽電子消滅に対するドーピングの影響–”，第 79回応用物理学会秋季学術講演会，名古屋国際会議場，名古屋，2018 年 9 月 20 日.
44. 福田清貴，浅井祐哉，関山口智広，本田慶祐，Sang Liwen，吉越章隆，上殿明良，石垣隆正，尾沼猛儀，

徹，角谷正友，“Al2O3/n-, p-GaN 構造の光熱偏向分光法による評価”，第 79回応用物理学会秋季学術講演会，名古屋国際会議場，名古屋，2018 年 9 月 19 日．

59

45. 浅井祐哉，関慶祐，吉越章隆，隅田真人，石垣隆正，上殿明良，角谷正友，“分子線酸素ビーム照射下その場観察 XPS による GaN 表面酸化の面方位依存性”，第 79 回応用物理学会秋季学術講演会，名古屋国際会議場，名古屋，2018 年 9 月 19 日．
46. 福田清貴，高島信也，尾沼猛儀，山口智広，本田徹，上殿明良，角谷正友，“光熱偏向分光法による Mg イオン注入 GaN 層の評価”，第 79 回応用物理学会秋季学術講演会，名古屋国際会議場，名古屋，2018 年 9 月 19 日．
47. 山下雄大，佐藤拓磨，都甲薫，上殿明良，末益崇，“化合物カルコゲナイド太陽電池の最新技術 - CIGS 系・CZTS 系・CTS 系太陽電池の高効率化とその課題 -”，第 79 回応用物理学会秋季学術講演会，名古屋国際会議場，名古屋，2018 年 9 月 19 日．
48. 角谷正友，福田清貴，上田茂典，浅井祐哉，Cho Yujin，関口隆史，上殿明良，尾沼猛儀，
Sang Liwen，山口智広，本田徹， ”Ⅲ-V 族窒化物の価電子帯構造およびギャップ内準位の評価”，第 79 回応用物理学会秋季学術講演会，名古屋国際会議場，名古屋，2018 年 9 月 20
日．
49. 笹

公和, 石井聡，大島弘行，高橋努，田島義一，大和良広，松村万寿美，森口哲朗，

関場大一郎，上殿明良，“筑波大学タンデム加速器施設 UTTAC の現状（2017 年度）”，第 31
回「タンデム加速器及びその周辺技術の研究会」，東京都市大学，東京，2018 年 7 月 13 日．
50. 清水美智子，R. Álvarez-Asencio，N. Nordgren，上殿明良，“水処理膜への応用を目指した
CNF/CA 複合膜の作製と特性解析”，セルロース学会第 25 回年次大会，京都大学，京都，2018
年 7 月 5 日．
51. A. Uedono, “Vacancy-type defects in hydrogen implanted GaN probed by positron annihilation”
Workshop on Plasma and Material Science, Univ. of Tsukuba, Tsukuba, 14th March 2019.
52. A. Uedono, “University of Tsukuba Campus-in-Campus program with University of Grenoble Alpes”,
Japan Academic Network, Lyon, France, 21th November 2018.
53. A. Uedono, “Characterization of materials for semiconductor devices by means of positron annihilation-Vacancy-type defects in metals, insulators, and semiconductors-” Seminar, Technische Univ. München,
9th July 2018.
54. 笹 公和，石井 聡，高橋 努，大和良広，田島義一，森口哲朗，上殿明良，“筑波大学タンデム加速器施設の現状報告”，第15回日本加速器学会年会，ハイブ長岡, 長岡,
2018年8月8-10日.

6055. 笹公和，細谷青児，高橋努，高野健太，落合悠太，大浦泰嗣，末木啓介，“6 MV タンデ

ム加速器質量分析装置における難測定核種 41Ca の高感度検出技術の進展”，日本原子力学会
2018 年秋の大会，岡山大学，岡山, 2018 年 9 月 5-7 日．
56. 村尾吉輝, 新田紀子, 土田秀次, 冨田成夫, 笹 公和, 平田浩一, 柴田裕実, 平野貴美, 山田
圭介, 千葉敦也, 斉藤勇一, 鳴海一雅, 星野 靖, “C60クラスターイオンビームを照射したSiとGeの表面構造評価”，日本金属学会 2019年春期大会，東京電機大学，東京, 2019年3月20-22
日.
57. 村尾吉輝, 新田紀子, 土田秀次, 冨田成夫, 笹 公和, 平田浩一, 柴田裕実, 星野 靖, 平
野貴美, 山田圭介, 千葉敦也, 斉藤勇一, 鳴海一雅, “C60クラスターイオンビームを照射した
SiとGeの表面構造”，QST高崎サイエンスフェスタ2018, 高崎シティーギャラリー, 高崎, 2018
年12月11-12日.
58. 村尾吉輝，新田紀子, 土田秀次, 冨田成夫, 笹 公和, 平田浩一, 柴田裕実, 平野貴美,
山田圭介, 千葉敦也, 斉藤勇一, 鳴海一雅, 星野 靖, “クラスターイオンを照射したSiとGeの形状比較” , ナノテク研シンポジウム2018, 高知工科大学, 高知, 2018年11月3日.
59. Tetsuya Matsunaka, Seiya Nagao, Mutsuo Inoue, Shinya Ochiai, Takami Morita, Shizuho Miki,
Takafumi Aramaki, Isao Kudo, Naoto Honda, Tetsutaro Takikawa, Kimikazu Sasa, Maki Honda, andKeisuke Sueki, “Anthropogenic iodine-129 in the Japan Sea Bottom Water and Dense Shelf Water ofOkhotsk Sea”, 日本地球惑星科学連合 2018 年大会，幕張メッセ, 千葉, 2018 年 5 月 20-24 日.
国際会議
60. 池端 慶, 服部浩一, 三橋武史, 黒澤正紀, 小室光世, 笹公和, 石井聡, 三好陽子,

島田和彦, 戸塚修平, 石橋純一郎，“中部沖縄トラフ伊平屋北海丘熱水域海底下の熱水変質鉱物の地球化学的特徴”，2018 年度資源地質学会年会，東京大学小柴ホール, 東京, 2018 年 6 月
27-29 日.
61. 松中哲也, 長尾誠也, 井上睦夫, 落合伸也, 笹公和, 森田貴己, 三木志津帆, 本多直人,

工藤 勲, 滝川哲太郎, 荒巻能史, 本多真紀, 末木啓介, “ヨウ素 129 を用いた日本海における海洋循環研究”，2018 年放射化学会年会, 京都大学, 京都, 2018 年 9 月 18-20 日.
62. 松村万寿美, 笹公和, 高橋努, 松中哲也, 高野健太, 落合悠太, 横山大輝, 末木 啓介,“筑波大学におけるヨウ素 129 の AMS 測定性能（2018 年度）”, 第 21 回 AMS シンポジウ
ム, 日本大学文理学部 百周年記念館, 東京, 2018 年 12 月 17-18 日.
63. 高野健太, 笹公和, 高橋努, 松村万寿美, 落合悠太, 末木啓介, 三宅芙沙, 堀内一穂,

松崎浩之, “宇宙線イベントにおける南極ドームふじアイスコア中の宇宙線生成核種 36Cl 変動”, 第 21 回 AMS シンポジウム, 日本大学文理学部 百周年記念館, 東京, 2018 年 12 月 17-61

18 日.
64. 落合悠太, 笹公和, 戸崎裕貴, 高橋

努, 松村万寿美, 高野健太, 太田祐貴, 末木啓介,

10“つくば市における宇宙線生成核種 Be, 36Cl の降下フラックス変動評価”, 第 21 回 AMS シ
ンポジウム, 日本大学文理学部 百周年記念館, 東京, 2018 年 12 月 17-18 日.
65. 松中哲也, 長尾誠也, 井上睦夫, 落合伸也, 笹公和, 高橋努, 本多真紀, 末木啓介,

森田貴己, 三木志津帆, 本多直人, 荒巻能史，“2017-2018 年における日本海固有水中のヨウ素 129 分布”， 第 21 回 AMS シンポジウム, 日本大学文理学部 百周年記念館, 東京, 2018 年
12 月 17-18 日.
66. 横山大輝, 末木啓介, 笹公和, 松中哲也, 高橋

努, 松村万寿美, 高野健太,

落合悠太,

涼, 太田祐貴，“福島県の帰還困難区域における I-129 の分布状況”，第 21 回 AMS

長谷川

シンポジウム, 日本大学文理学部 百周年記念館, 東京, 2018 年 12 月 17-18 日.
67. 松中哲也, 笹公和, 松村万寿美, 平尾茂一, 脇山義史,“I-129/Cs-137 比を用いた新田川における放射性のヨウ素とセシウムの動態解析”, 第 5 回福島大学環境放射能研究所成果報告会「避難区域の再生~現状とこれから~」, 福島大学, 福島, 2019 年 3 月 14-15 日.
68. 笹公和, 細谷青児, 本多真紀, 高橋

努, 佐藤志彦, 高野健太, 落合悠太, 末木啓介,“加速器質量分析法によるストロンチウム 90 の迅速かつ高感度な検出手法の開発”, 2018 年度 日
本地球化学会年会第 65 回年会, 琉球大学, 沖縄, 2018 年 9 月 11-13 日.
69. 落合悠太, 笹公和, 戸崎裕貴, 高橋

努, 松村万寿美, 高野健太, 太田祐貴, 末木啓介, “加速器質量分析法を用いた宇宙線生成核種 36Cl の降下フラックス変動評価”, 2018 年度 日本地球化学会年会第 65 回年会, 琉球大学, 沖縄, 2018 年 9 月 11-13 日.
70. 高野健太, 笹公和, 高橋努, 松村万寿美, 落合悠太, 末木啓介, 三宅芙沙, 堀内一穂,
10

松崎浩之, “宇宙線生成核種 Be と 36Cl を用いた 5480 BC 宇宙線イベントの原因解明に向けた研究”,2018 年度 日本地球化学会年会第 65 回年会, 琉球大学, 沖縄, 2018 年 9 月 11-13

日.
71. 平田浩一, 山田圭介, 斎藤勇一, 鳴海一雅, 千葉敦也, 平野貴美, 冨田成夫, 笹公和，“高感度微小領域分析を目指した高速クラスターイオン照射の高度化”，日本物理学会第 74 回年次大会，九州大学（伊都キャンパス）, 福岡, 2019 年 3 月 14〜17 日.
72. 坂口綾, 浅井駿佑, 山﨑信哉, 笹公和, 高橋努, 落合悠太, Ismail Md. Mofizur Rahman,

90

末木啓介, “環境中 Sr 測定における加速器質量分析の性能評価”,第 5 回福島大学環境放射能研究所成果報告会「避難区域の再生~現状とこれから~」,

62

福島大学, 福島, 2019 年 3 月 14-

15 日.
73. 森口哲朗, “筑波大学 6MV タンデム加速器施設における偏極陽子ビームを用いた核モーメン
トの測定”, 第 10 回 停止・低速 RI ビームを用いた核分光研究会, 九州大学伊都キャンパス,福岡, 2019 年 03 月 18-19 日.
74. 森口哲朗, “固体水素標的を用いた 17Ne の反応断面積測定”, 日本物理学会第 74 回年次大会、
九州大学伊都キャンパス, 福岡, 2019 年 03 月 14-17 日.
75. 森口哲朗, “固体水素標的を用いた不安定核のスキン厚導出手法の開発”, H29 年度 HIMAC 共
同利用研究成果発表会, ホテルポートプラザ千葉, 千葉, 2018 年 4 月 16-17 日.
76. 向井もも, “稀少 RI リングにおける中性子過剰 Ni 領域の質量測定”, 核データと重元素合成を中心とする宇宙核物理研究会, 北海道大学、札幌, 2019 年 3 月 6-8 日.

6.4

UTTAC seminars

2018.11.8

β-γ spectroscopy of neutron-rich nucleus 195Os, Murad Ahmed (University of Tsukuba)

2018.11.26 Measurement of the sixth order cumulant of net-charge distributions in Au+Au collisions at
the STAR experiment, Tetsuro Sugiura (University of Tsukuba)
2018.12.3

Study of event-plane dependent di-hadron correlations with event shape engineering at theSTAR experiment, Ryo Aoyama (University of Tsukuba)

2018.12.4

Measurements of inclusive charged jet properties in pp and Pb-Pb collisions at √𝑠= 5.02

TeV with the ALICE experiment at the LHC, Ritsuya Hosokawa (University of Tsukuba)
2018.12.12

Nuclear magnetic moment of neutron-rich nucleus 21O, Yoko Ishibashi (CYRIC, Tohoku
University)

2019.1.15

Study of directed flow to clarify the structure of the first-order phase transition in √𝑠=

4.5 GeV Au+Au collisions at the STAR Fixed Target experiment, Hiroki Kato (University ofTsukuba)63

2019.1.15

Study of transverse momentum and multiplicity dependence of heavy-flavour production via
single electrons in pp collisions at √𝑠 = 13 TeV with ALICE at the LHC, Toma Suzuki(University of Tsukuba)

2019.1.15

Measurement of electrons and jets from heavy flavour in pp collisions at √𝑠 = 5.02 TeV andp-Pb collisions at √𝑠= 8.16 TeV with ALICE at the LHC, Daichi Kawana (University ofTsukuba)2019.1.15

Azimuthal angle dependence of quantum interferometry relative to the event plane in √𝑠=

200 GeV Au+Au and Cu+Au collisions at RHIC-STAR, Yota Kawamura (University ofTsukuba)2019.1.16

Study of cosmic ray events and measurements of cosmogenic radionuclide 36Cl by accelerator
mass spectrometry, Kenta Takano (University of Tsukuba)

2019.1.16

Development of time-of-flight detector and position-sensitive detector using secondary
electrons emitted from a thin foil, Daiki Kamioka (University of Tsukuba)

2019.1.16

Measurement of multiplicity dependent di-hadron correlations in √𝑠collisions at STAR, Kazuya Nakagawa (University of Tsukuba)

64= 200 GeV d+Au

7.
THESES

Doctor theses
Murad Ahmed

β-γ spectroscopy of neutron-rich nucleus 195Os

Yoko Ishibashi

Nuclear magnetic moment of neutron-rich nucleus 21O

Yoko Shiina

Response of electrons in solid under irradiation of fast cluster ions

Master theses
Daiki Kamioka

Development of time-of-flight detector and position-sensitive detector using
secondary electrons emitted from a thin foil

Kenta Takano

Study of cosmic ray events and measurements of cosmogenic radionuclide 36Cl
by accelerator mass spectrometry

Yuki Ota

Evaluation of 36Cl in soil around Fukushima Daiichi nuclear power plant using
AMS

Junichi Kikuda

Observation of hydrogen in p-type GaN using RBS/ERDA and channeling NRA

Naoka Hiruta

Beam optics analysis of hydrogen recoils in high-resolution ERDA

Yuki Sugisawa

Development of TOF-E telescope ERDA for light element quantification in
multi-layer films

Undergraduate theses
Yusuke Iwai

Detection of 10-100 keV particles using Superconducting Tunnel Junction

Hiroki Yokoyama

Distribution of 129I inventory in difficult-to-return zones in Fukushima Prefecture

Shunsuke Asai

Development/improvements of analytical technique for Sr-90 measurement using
AMS

65

8.
LIST OF PERSONNEL

Tandem Accelerator Complex
A. Uedono

Director, Professor

K. Sasa

Associate Professor

D. Sekiba

Lecturer

T. Moriguchi

Assistant Professor

Y. Tajima

Mechanical Engineer

S. Ishii

Mechanical Engineer

T. Takahashi

Electrical Engineer

Y. YamatoElectrical Engineer

M. Matsumura

Technical Assistant

S. Kuramochi

Administrative Staff

M. Satoh

Administrative Staff

H. Muromachi

Administrative Staff

Research Members1
Division of Physics
A. Ozawa

T. Moriguchi

T. Yamaguchi*

M. Mukai

K. Sasa

S. Suzuki

S. Tomita

Division of Applied Physics
E. Kita

D. Sekiba

S. Sharmin

A. Uedono

H. Yanagihara

M. Ohkubo**

Division of Geoscience
M. Kurosawa

K. Ikehata

Division of Chemistry
K. Sueki

A. Sakaguchi

S. Yamasaki

Division of Information and Systems
T. Kameda

1

The “research members” include the authors and coauthors within 5 years back from this fiscal year, as well as themembers of research projects running at UTTAC.
* Cross appointment from Saitama University.
**Visiting Professor from National Institute of Advanced Industrial Science and Technology [AIST].

67

Staff of Open Advanced Facilities Initiative
H. KudoH. Naramoto

M. SatakaK. Awazu (National Institute of Advanced Industrial Science and Technology [AIST])S. Aoki (Comprehensive Research Organization for Science and Society [CROSS])
Staff of Joint Research Projects with Other Organizations
A. Yamazaki (Cross-ministerial Strategic Innovation Promotion Program [SIP])2
Graduate students
Graduate School of Pure and Applied Sciences
Graduate School of Life and Environmental Sciences
M. Ahmed

Y. Shiina

Y. LiuH. Latiff

Y. Hisamatsu

T. Tainosho

D. Kamioka

K. TakanoY. Ochiai

R. Kagesawa

H. Onoda

H. Koizumi

R. Shigesawa

M. Hagiwara

T. Itou

A. Ogura

N. Onozato

Y. OtaY. Sugisawa

J. Kikuda

A. Nagata

A. Yasuda

M. Hashimoto

M. DateK. Hattori

Y. Asai

R. MaseS. Yaguchi

W. UenoS. AndoA. Taira

S. Yamada

Y. Iwai

K. Kimura

R. AbeT. Okamoto

S. Asai

H. Yokoyama

Y. Takahara

R. Yaguchi

R. Suganuma
Undergraduates

External users and collaborators
Y. Tosaki

National Institute of Advanced Industrial Science and Technology (AIST)

K. Hirata

National Institute of Advanced Industrial Science and Technology (AIST)

S. Shiki

National Institute of Advanced Industrial Science and Technology (AIST)

S. Yamashita

The University of Tokyo

Y. Katou

The University of Tokyo

N. Nagakura

The University of Tokyo

K. Fujii

The University of Tokyo

2

Also, a staff of Open Advanced Facilities Initiative68

S. Kajiwara

The University of Tokyo

T. Mogi

The University of Tokyo

Y. Hirose

The University of Tokyo

D. Kutsuzawa

The University of Tokyo

T.Wakasugi

The University of Tokyo

T. Matsunaka

Kanazawa University

H. Arakawa

Saitama University

K. Inomata

Saitama University

K. Nishimuro

Saitama University

T. Kobayashi

Saitama University

Y. Inada

Saitama University

S. Hosoi

Saitama University

M. Sakaue

Saitama University

K. Yokota

Saitama University

69