UTTAC-89, 2020

UTTAC
ANNUAL REPORT 2019

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

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

UTTACANNUAL REPORT 2019
April 1, 2019– March 31, 2020

UTTAC-89, 2020

Editors : Tetsuaki Moriguchi, Kimikazu Sasa, Yoshihiro Yamato, Masumi Matsumura,
Masao Sataka, Hiroshi Naramoto, Eiji Kita, 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 © 2019 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

Cover: Hydrogen aggregates of ten-μm size in H-charged Al [AIP Adv. 9 (2019) 105111],
from Report 4.2.

PREFACE
This annual report covers researches carried out at University of Tsukuba Tandem
Accelerator Complex (UTTAC) during the fiscal year 2019 (1 April 2019 ~ 31 March
2020). 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 1, 2020
Editorial board

High-school students visited far from Kagoshima prefecture. In FY2019, we
had 428 visitors including 290 high-school students. Social activity of UTTAC
to promote physical science to young generation has been continued in addition
to science and technology researches.

-i-DEEP CONTRIBUTION TO MACHINE OPERATION EXPECTED FOR STUDENTS

Reduction of labor costs in Japan eventually led to the reduced number of technical staff at UTTAC. As
a result, users are required more and more to proceed with their experimental researches under minimum
technical support. Even partial operation of the accelerator and the beam-transport system by the users,
especially students, might be very helpful for the UTTAC staff.

Graduate students watching the control panel of the 6MV tandem
accelerator, with a little tension.

Graduate student carefully adjusting the slit system to shape a He microbeam for materials analysis.

- ii -

CONTENTS

1. ACCELERATOR AND RELATED FACILITIES
1.1

Accelerator operation 2019 ················································································

1

1.2

Current distribution of ions accelerated by the 6MV tandem accelerator···························

3

1.3

Air dose rates during deuteron irradiation································································

5

2. NUCLEAR AND ATOMIC PHYSICS
2.1 Studies of nuclear polarization in different types of Si targets·········································

7

2.2 Developments of RF system for rotating magnetic field···············································

8

3. ACCELERATOR MASS SPECTROMETRY
3.1

Performance report of the Tsukuba 6 MV multi-nuclide AMS system in fiscal 2019··············
14

10

3.2

Reconstruction of C introduction history in the Japan Sea using coral samples·················

12

3.3

Regional dependences of 10Be and 36Cl concentrations in rainwater································

14

3.4

The Performance of Iodine-129 AMS measurements at the University of Tsukuba in
FY 2019······································································································

16

3.5

Anthropogenic iodine-129 depositions at the Japan Sea and Pacific sides of the archipelago,
during 2017-2018··························································································

18

4. BEAM AND ISOTOPE APPLICATIONS
4.1

Vacancy-type defects in Mg implanted GaN studied by positron annihilation spectroscopy··

20

4.2

Microscopic 3-dimensional mapping of hydrogen bubbles in Al by elastic recoil detection
analysis under transmission geometry·································································

22

Depth resolution of hydrogen distribution in Al measured with elastic recoil detection
analysis under transmission geometry·································································

24

4.4

Trial of 7Li depth profile determination by 7Li(p, α)4He NRA·····································

26

4.5

Depth profiling of lithium by use of TOF-E telescope ERDA·····································

28

4.6

High magnetic field Mössbauer study on an antiferromagnetic layered FeNi nitride, FeNiN·

30

4.7

Simultaneous detection of light elements under non-Rutherford scattering······················

32

4.8

Recombination effect in the output pulse height of superconducting tunnel junction for theincidence of keV ions····················································································

34

Heteroepitaxial growth of thin films of the perovskite oxynitride CaTaO2N by reactive
magnetron sputtering·····················································································

36

Electric properties of magnesium titanium oxynitride thin films··································

38

4.3

4.9
4.10

- iii -

5. BEAM IRRADIATION EFFECT
5.1

Study on microalgae mutagenesis with 15N-resonant nuclear reaction······························

40

6. LIST OF PUBLICATIONS AND PRESENTATIONS
6.1

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

42

6.2

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

47

6.3

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

48

6.4

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

56

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

58

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

59- iv -

1.
ACCELERATOR AND RELATED FACILITIESInside view of the UTTAC 6MV tandem accelerator. The acceleration
tube is surrounded by metal hoops of 1-m diameter.

1.1

Accelerator operation 2019

K. Sasa, S. Ishii, Y. Tajima, T. Takahashi, Y. Yamato, M. Matsumura, T. Moriguchi
1 MV Tandetron accelerator
The operating time and the experimental beam time of the 1 MV Tandetron accelerator were 335.7 and139.5 hours, respectively, during the total service time in fiscal 2019. The total number of operation days
was 49 in fiscal 2019. A total of 28 research programs was carried out and a total of 147 researchers usedthe 1 MV Tandetron accelerator in fiscal 2019. Figures 1 and 2 show classification of the accelerated ionsand of the experimental purposes, respectively. This accelerator was maximally used for RBS/ERDA which
occupied 64% of the beam time.
Beam test
15%
Education
4%
Clusterphysics
5%

RBS /
ERDA
64%

Biomedical
research
12%

Fig. 2. Purpose of use of the 1 MV Tandetron
accelerator in fiscal 2019.

Fig. 1. Accelerated ions by the 1 MV Tandetron
accelerator in fiscal 2019.
60

An alignment adjustment of the Tandetron
accelerator was performed in March 2019 [1]50

because there was a beam-axis deviation after
comparison of beam transmissions from thefront of the accelerator tank to the C course
chamber for 2003 and 2019. The beam

40

Beam Transmission (%)

the earthquake in 2011. Figure 3 shows the▲ Beam transmission (2019)× Beam transmission (2003)

30

20

10

transmission was recovered after the alignment
0adjustment, especially it was improved in thehigh energy range than before.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2.2

Beam Energy (MeV)

Fig. 3. Comparison of beam transmissions from the front of theaccelerator tank to the C course chamber for 2003 and 2019.

6 MV Pelletron tandem accelerator
The operating time and the experimental beam time of the 6 MV Pelletron tandem accelerator were1

1349.7 and 1036.6 hours, respectively, during the total service time in fiscal 2019. The total number ofoperation days was 112 in fiscal 2019. A total of 53 research programs was carried out and a total of 277
researchers used the 6 MV Pelletron tandem accelerator in fiscal 2019. Figure 4 shows the beam time
histogram with respect to the terminal voltage. Figures 5 and 6 show classification of the accelerated ionsand of the experimental purposes, respectively. The operating time at terminal voltages of 5 and 6 MV
accounted for 92% of all the beam time. The terminal voltage at 5 MV was mainly used for 129I AMS. On
the other hand, the terminal voltage at 6 MV was applied for 36Cl AMS, nuclear physics and the radiation
resistant test of semiconductors. This accelerator was used most often for AMS which occupied 76% of thebeam time. The next 11% was occupied by
nuclear physics using polarized beams,
mainly for study of nuclear moments ofunstable nuclei.
In 2019, Typhoon No.19 caused a lot of
detriment at the accelerator facility on
October. The cooling water chiller for the
1 MV Tandetron and the peripheral
equipment were damaged by flooding. In
addition, radiation posts were not capableof being used for monitoring. They will be
restored with the reconstruction budget in

Fig. 4. Beam time histogram as a function of the terminal voltage
for the 6 MV Pelletron tandem accelerator in fiscal 2019.

2020.

Ni
1.1%

IBA
（RBS/ERDA/NRA)
4%

H
15.8%

I
19.6%

Proprietary Research
3%

Beam test
4%

D
2.1%

Cu
0.2%
Ti
0.3%
Ca
0.1%

Radiation
Resistance Test
2%

Nuclearphysics
11%

He
1.5%
Be
9.8%

Cl
24.3%

S
0.7%

F
0.3%

O
0.8%

AMS
76%

C
23.5%

Fig. 5. Accelerated ions for the 6 MV Pelletron
tandem accelerator in fiscal 2019.

Fig. 6. Purpose of use of the 6 MV Pelletron
tandem accelerator in fiscal 2019.

Reference[1] K. Sasa et al., UTTAC ANNUAL REPORT 2018, UTTAC-88 (2019) 1.

2

1.2

Current distribution of ions accelerated by the 6MV tandem accelerator

M. Sataka, T. Takahashi, H. Naramoto, H. Kudo, K. Sasa
Beam current of ions accelerated by the 6MV tandem accelerator has been investigated as a function of
the ion charge state since 3 year ago [1-3], mainly at acceleration voltages of 1, 3 and 6 MV. Here, we
describe the ion current distribution only for the 6 MV terminal voltage, hence the measured highest charge
state of the ion gives the highest energy of the ion obtained by this accelerator. In this fiscal year, Ca, Ti,
and Cu ion were newly tested.
Figure 1 shows the beam current distributions of Cun+ as a function of the ion charge state n at a terminal
voltage of 6 MV. Either Ar gas or a carbon foil was used as a charge-changing stripper at the high-voltage
terminal. The Ar gas pressure was about 5-7 μPa, and the thickness of the carbon foil was about 5 μg/cm2.
The ion current distribution for the foil stripper shifts to higher charge state by about 5 than for the Ar gas
stripper. The practical maximum energy of 84 MeV is obtained for Cu13+ using the foil stripper.

Ion Current (nA)

100

Foil

Gas

13

14

10

1

0.1
2

3

4

5

6

7

8

9

10

11

12

15

Ion Charge State, nFig. 1. Beam current distribution of Cun+ for the terminal voltage of 6 MV. Either gas or foil strippers
was used at the high-voltage terminal.
We have tested injection of negatively charged molecular ions to the high-voltage terminal. In this year,
molecular ions of Ca and Ti hydrides were tested. Since the molecular ions break up into the constituent
atoms when they pass through the charge-stripper, the accelerated ion energy cannot be determined uniquelyby the terminal voltage and the ion charge state after acceleration. The maximum acceleration energy in thistest was slightly less than 66 and 78 MeV for Ca, and Ti, respectively. The slight energy differences fromthe monoatomic cases are due to the extremely lighter mass of the constituent H than that of Ca or Ti.
Table 1 shows the ion current distribution of Ca and Ti, together with the previous data for Al, Mo, andW. Furthermore, Table 2 shows the ion charge and ion energy obtained in the case of negative atomic-ion
injection at the 6 MV terminal voltage, which were investigated from 2016 to 2019.

3

.
Table 1. Ion current distribution of N, Al, Ca, Ti, Mo and W at
the 6 MV terminal voltage. The measured beam intensities areshown by the symbols: ○: ≥ 1nA, △: ≤1nA. Shown in red are
the data with the foil stripper.

charge
state
14
13
12
11
10
9
8
7
6
5
4
3
2
1

N

Al

Ca

Mo

△
〇
〇
〇
〇
〇
〇
〇
〇
〇

△
△
△

〇
〇
〇
〇
〇

△
〇
〇
〇
〇

Ti

△
△

W

△
△
〇
〇

△
〇
〇
〇
〇
〇
〇

Table 2. Summary of the acceleration investigation for negative atomic ion injection at the 6 MV terminal
voltage from 2016 to 2019. The measured beam intensity is shown by the symbols: ○: ≥ 1nA, △: ≤1nA.
Shown in red are the data with the foil stripper.
charge energy
state （MeV） H
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 〇

He

〇
〇

Li

〇
〇
〇

B

〇
〇
〇
〇

C

〇
〇
〇
〇
〇

O

〇
〇
〇
〇
〇
〇
〇

F

〇
〇
〇
〇
〇
〇
〇

Al

〇
〇
〇
〇
〇
△

Si

〇
〇
〇
〇
〇
〇
〇
〇

S

△
〇
〇
〇
〇
〇
〇
〇
〇
〇

Cl

〇
〇
〇
〇
〇
〇
〇
〇
〇

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.
[3] M. Sataka et al., UTTAC Annual Report 2018, UTTAC-88 (2019) 5.

4

Ca

△
△
△
△
△

Ni

△
〇
〇
〇
〇
〇
〇
〇
〇
〇

Cu
△
〇
〇
〇
〇
〇
〇
〇
〇
〇

Br
△
△
〇
〇
〇
〇
〇
〇
〇
〇
〇

Ag
△
△
〇
〇
〇
〇
〇
〇
〇
〇

I
〇
〇
〇
〇
〇
〇
〇
〇

Au
△
△
〇
〇
〇
〇
〇

1.3

Air dose rates during deuteron irradiation

T. Moriguchi, M. Matsumura, K. Sasa, S. Ishii, T. Takahashi, Y. Yamato
Monitoring air dose rates is necessary for radiation safety management in accelerator facilities. In
FY2019, as a test beam, deuteron was accelerated by the 6 MV Pelletron tandem accelerator for the firsttime. We measured air dose rates in the radiation controlled area during deuteron irradiation. These data
are expected to be useful for the radiation safety in UTTAC.
Figure 1 shows the layout of the 6 MV Pelletron tandem accelerator facility. A deuteron beam was
extracted from Polarized ion source (PIS) or SNICS-II (S2). The beam energy was changed from 3 to 12
MeV, and the beam current was approximately 30 nA. In the present measurement, tantalum (Ta) andcarbon (C) were used as beam stoppers. These stoppers were installed at three positions which areindicated by solid arrows in Fig. 1. Air dose rates were measured by three pairs of area monitors for
gamma-ray (DAM-102, Hitachi Ltd.) and neutron (DAM-251, Hitachi Ltd.). These area monitors arelocated at the shielding walls which are indicated by dashed arrows in Fig. 1. Irradiation time was set tomore than ten minutes to stabilize air dose rates. To compare the results of deuteron irradiation with thosefor proton, we also measured air dose rates during 12 MeV proton irradiation. The proton beam current
was adjusted to approximately 300 nA which is acceptable for radiation safety.

Fig. 1. Layout of the 6 MV Pelletron tandem accelerator facility. Solid arrows indicate the positions of beam
stoppers: tantalum (Ta1, Ta2 and Ta3) and carbon (C). Dashed arrows indicate the positions of three pairs ofarea monitors for gamma-ray and neutron (Monitor-1, Monitor-2 and Monitor-3).

5

Figure 2 shows air dose rates measured by the nearest area monitor to the irradiated stopper. For
tantalum stoppers, air dose rates of both gamma-ray and neutron during deuteron irradiation are lower thanthose during 12 MeV proton irradiation. As shown in Fig. 2 (b), for irradiation with 6 and 8 MeV
deuterons, the air dose rates for tantalum are lower than for carbon. This trend is consistent with the caseof 22 MeV deuteron [1]. These results suggest that for deuteron irradiation tantalum is one of the effective
materials for reducing air dose rates of both gamma-ray and neutron. For proton irradiation, the tantalum
stopper seems effective for reducing air dose rate of gamma-ray, while the carbon stopper seems effective
for reducing that of neutron, as shown in Fig. 2 (b). For the radiation safety management in UTTAC, we
will collect additional data of air dose rates by varying beam stoppers and radiation shields.

Fig. 2. Air dose rates of gamma-ray (upper panels) and neutron (lower panels) measured by (a) Monitor-1,(b) Monitor-2 and (c) Monitor-3. These results were obtained by the nearest area monitor to the irradiatedstopper. Blue and red symbols represent the results of proton (H) with approximately 300 nA and deuteron(D) with approximately 30 nA irradiations, respectively. Circles and crosses represent the results fortantalum (Ta1, Ta2 and Ta3) and carbon (C) stoppers, respectively. Note that backgrounds were already
subtracted.

Reference[1] K. Shima, UTTAC Report No. 12, UTTAC-J-12 (2004) 3 (in Japanese).

6

2.
NUCLEAR AND ATOMIC PHYSICS

Spin-polarized ion source2.1

Studies of nuclear polarization in different types of Si targets

A. Ozawa, T. Moriguchi, Y. Yamato, M. Mukai, R. Kagesawa, K. Tomita, T. Yamaguchi
We are attempting to produce polarized unstable nuclei by using polarized proton beams for the aim ofmeasuring nuclear moments of unstable nuclei. In FY2018, we have succeeded to observe magnetic
moments of 25Al and 29P at Ep=12 MeV with a Si target (n-type, low-impedance (n-Low)) [1]. In FY2019,
we have studied nuclear polarization produced in the different types of Si targets. In this time, we tried Si(n-Low), Si (n-High), Si (p-Low) and Si (p-High).
We checked polarization degree in the different targets by using nuclear magnetic resonance system for

β-rays (β-NMR system). Experimental setup and experimental procedure are the same as those in theprevious measurement [2]. In the present work, a 0.5 mm thick Si target placed in our β-NMR system wasirradiated with the polarized proton beams accelerated to 12 MeV by the 6 MV tandem accelerator. Proton
polarization-degree was about 70 %. In this work, to obtain the polarization degree for 29P in our β-NMR
system, we changed the radio frequency (RF) with the fixed static magnetic field (about 1.6 kG). Figure 1
shows the NMR spectra observed for the different Si targets. Clear dips at 2.95 MHz correspond to themagnetic moment of 29P (1.2349 n.m.). Depths of the dips from those without RF correspond to thepolarization degrees. We observed the large polarization degrees for Si (n-High) and Si (p-High),
respectively. The large target dependence for the polarization degree may suggest the difference of hyperfine
interactions inside the Si targets. In further studies, we will measure relaxation times and precise
resonance dips to investigate hyperfine interactions inside the Si targets.

1.01

NMR effect

1.00
0.99
0.98
0.97
2.8

2.9

3.0

3.1

2.8

2.9

3.0

3.1

2.8

2.9

3.0

3.1

2.8

2.9

3.0

3.1

RF (MHz)

Fig. 1. Typical NMR spectra measured by using the 12 MeV polarized proton beams with different typesof Si targets ((a) Si (n-Low), (b) Si (n-High), (c) Si (p-Low) and (d) Si (p-High)). Open circles are data
without RF.
References[1] A. Ozawa et al., UTTAC ANNUAL REPORT 2018, UTTAC-88 (2019) 7.
[2] A. Ozawa et al., UTTAC ANNUAL REPORT 2017, UTTAC-87 (2018) 7.

7

2.2

Developments of RF system for rotating magnetic field

K. Tomita, A. Ozawa, T. Moriguchi, M. Mukai, R. Kagesawa
Magnetic moment (±μ) is one of the important physical quantities for nuclear structure. A techniquecalled β-NMR is used to measure the nuclear magnetic moment of unstable nuclei. Using β-NMR, nuclear
magnetic resonance is detected by observing the asymmetry of β-rays emitted from unstable nuclei with
nuclear polarization. The sign of the nuclear magnetic moment is decided by using a rotating magnetic field
produced by a pair of two radiofrequency (RF) coils whose central axes are orthogonal to each other [1]. RF
signals for both coils are necessary to adjust to the same amplitude and frequency under 90-degree phasedifference to rotate the magnetic field. If the sign of the nuclear magnetic moment is positive, its resonanceis detected in the right (left)-handed rotational field for upward (downward) static magnetic field. In FY2019,
we were attempting to develop the RF system, including RF coils.
We have made a pair of RF coils with a diameter of 11.3 mm, a gap of 12.0 mm and a size of 30.6 mm(Fig. 1). Copper was used for wire (φ1.1 mm) of coils. Figure 2 shows a schematic diagram of the RF system.
The frequency of the RF coil was set to 3.05−3.15 MHz by using a function generator. The amplitude wasadjusted by an attenuator. A cable delay was added to Coil-A for the ±90-degree phase shift. The variable
condensers were used to adjust the resonance frequencies of the coils. It is important to confirm that theresonance frequencies of the two pairs of coils can be changed independently without interference whichmight be unintentionally caused by the mutual inductance of the coils.

Fig. 1. RF coil for a rotating magnetic field. CoilA and Coil-B are perpendicular and parallel to thespin-polarized beam, respectively. Green arrows
indicate the assumed positive direction of theelectric current.

Fig. 2. Schematic diagram of the RF system.

Figure 3 shows the RF signals observed by the oscilloscope. As shown in Fig. 3, we added a 90 (250)ns delay to Coil-A for the −90 (+90) degree phase shift. RF signals in Fig. 3 (a) and (b) correspond to right-

8and left-handed rotating magnetic fields, respectively.

Fig. 3. The RF signals observed by the oscilloscope with (a) 90 ns and (b) 250 ns cabledelays. Blue and yellow curves indicate RF signals for Coil-A and Coil-B, respectively.

Fig. 4. Amplitudes of RF signals modulated from 3.05 to 3.15 MHz during 100 ms, measured for Coil-A (blue)
and Coil-B (yellow). Labels (a), (b), and (c) correspond to three capacitance values of the variable condenser
for Coil-A.

Figure 4 shows the amplitudes of RF signals modulated from 3.05 to 3.15 MHz during 100 ms, whichwere measured for three capacitance values changed by the variable condenser for Coil-A. As seen in Fig.
4, while the resonance frequency for Coil-A changes considerably, that for Coil-B remains unchanged in the
middle of the modulation time. This indicates that both resonance frequencies can be controlled
independently without any noticeable interference.
We plan to determine the sign of the nuclear magnetic moment for 29P using the present RF system.
Reference[1] Y. Ishibashi et al., UTTAC annual report 2014, UTTAC-84 (2014) 8.

93.
ACCELERATOR MASS SPECTROMETRY

AMS sample of the ice (cut to ~50 cm length) obtained from 3028-meter
underground of the Dome Fuji, Antarctica, which informs us of the
global environment 0.72 million years ago.

3.1

Performance report of the Tsukuba 6 MV multi-nuclide AMS system infiscal 2019

K. Sasa, T. Takahashi, Y. Ochiai, M. Matsumura
The AMS system on the 6 MV tandem accelerator was operated for a total of 61days and 792.9 hours
in fiscal 2019. We measured 694 samples in total dealing with rare radionuclides such as 10Be, 14C, 36Cl
and 129I shown in Table 1. Figure 1 shows details of the measured nuclides. Figure 2 showsmonthly-measured nuclides from April 2019 to March 2020. 129I was measured most frequently in fiscal
2019 in order to investigate the radioactive contamination in surface soils, and to trace the oceanic
circulation in the Japan Sea. 14C was measured for 14C introduction history in the Japan Sea using coral
samples. 36Cl was applied for tracing cosmic ray events remaining in the ice core. In addition, 10Be and36

Cl were measured to investigate regional dependence of their concentrations in rainwater.
Be-10
12%

Table 1. Number of measured samples infiscal 2019.

NuclidesNumber

Be-10

85

C-14

187

Cl-36

165

I-129

257

Total

694

I-129
37%
C-14
27%

Cl-36
24%
Fig. 1. Measured nuclides by the multi-nuclide

AMS system in fiscal 2019.

Fig. 2. Monthly-measured nuclides by the multi-nuclide AMS system from April 2019 to March 2020.

10

The low-background measuring methods were developed for 36Cl AMS by comparing beam conditions
at 6 MV. We measured the 36Cl/Cl background under different beam conditions, i.e., 36Cl5+ with the beamenergy of 36.0 MeV (using an argon gas stripper), 36Cl7+ with 48.0 MeV (using a carbon foil stripper), and36

Cl8+ with 54.0 MeV (using a carbon foil stripper). The beam transmissions were 22, 15, and 10% for

36

Cl5+, 36Cl7+, and 36Cl8+, respectively. Figure 3 shows 36Cl/Cl background against separation factors

between 36Cl and 36S spectrums [1] obtained for the three beam conditions. It is noted that AgCl blanksamples used in the measurements were prepared from ACS-grade NaCl (Fisher Scientific, USA). The
background ratios of 36Cl/Cl ~ 3 × 10−15 were achieved for 36Cl AMS.

5.0

36

Background Cl/Cl (10-15)

4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
1.35

36.0 MeV
48.0 MeV
54.0 MeV

1.40

1.45

1.50

1.55

Separation M (channel)
Fig. 3. Background 36Cl/Cl against separation factors between 36Cl and 36S
spectrums for the three beam conditions.

Reference[1] S. Hosoya et al., Nucl. Instr. Meth. Phys. Res. B 438 (2018) 131.

11

3.2

Reconstruction of 14C introduction history in the Japan Sea using coral
samplesK. Nishizuka, A. Sakaguchi, T. Omori, K. Sasa, T. Takahashi, M. Matsumura, Y. Ochiai, S. Yamasaki,
K. Sueki
A large amount of carbon-14 (14C, T1/2 = 5730 yr) has been released into the environment by nuclear
facilities, and also in nuclear tests conducted by the US and the former USSR in the 1950s and 1960s. Such
14

C is quickly oxidized and spreads into the atmosphere as 14CO2, and some part is dissolved in surface

seawater and transported to greater depths and to other seas by seawater circulation and/or diffusion. It is
known that reef-building corals form annual rings by fixing the carbon dissolved in seawater to their own
carbonate skeletons. Therefore, it is possible to reconstruct the isotopic composition of past surface seawater,
particularly concerning 14C, by performing isotopic analysis of each annual coral ring.
Studies utilizing the corals in this manner have been conducted in the North West Pacific, from the low
latitudes around the equator to the Tsushima Strait which is the northern-most limit of reef-building corals[1−3]. However, no dataset of carbon isotopes before 1966 exists in the study using a coral core sample
from the Tsushima Strait, the entrance to the Japan Sea. Although Tsushima Strait is located on the latitude
where numerous atmospheric nuclear tests were conducted and the temperature of the seawater in the strait
is low compared to other sampling sites, lower 14C concentrations there than in lower latitudes have beenreported [3]. In the present study, we measured the carbon isotopic compositions in a coral core collectedfrom Iki Island, Tsushima Strait, in order to reconstruct the history of the introduction of 14C into the Japan
Sea since the 1940s (i.e., before any atmospheric nuclear test was conducted).
The coral (Dipsastraea Speciosa) cores were collected from Iki Island in the Tsushima Strait inNovember 2012 and dated using soft X-ray photographs and LA-ICP-MS Sr/Ca ratio measurements [4]. To
determine which pretreatment leaching method should be employed, the coral powders (1930s) wereleached with different concentrations of hydrochloric acid (2−6×10−3 M). The coral sample residues wereanalyzed by accelerator mass spectrometry (AMS), powder X-ray crystal structure analysis, scanningelectron microscopy, and also by isotope ratio mass spectrometry for stable isotopic composition of carbon
and oxygen (13C/12C, 18O/16O). Using the appropriate pretreatment method, the carbon isotope ratios (14C/12C,
13

C/12C) in annual rings were measured by AMS for 23 samples over the period 1943 to 2011. It should be

noted that no remarkable effects were observed on the surfaces of the coral samples after removing surface
contamination by hydrochloric acid leaching. Thus, we concluded that no specific chemical leaching wasnecessary for the actual samples.
Figure 1 shows the variations of Δ14C, which represents the relative 14C amount [5], in the past surface
seawater reconstructed from the annual rings in the coral cores from Iki Island. The Δ14C value before
commencement of atmospheric nuclear testing was −59 ‰, then increased rapidly from around 1960 before
reaching its maximum (147 ‰) in 1971, and then gradually decreased over the following years. While the
Δ14C values for the 1960s are larger than those in the previous study [3], the reason for this discrepancy is
not clear at present. For further discussion of this subject, it is necessary to investigate the crystal structure12

of the coral skeleton to determine whether diagenesis occurred, as well as to reconsider the dating method
employed. However, the following are conceivable explanations for the higher Δ14C values in Iki coralcompared to more southern areas such as Guam and Ishigaki island. The Tsushima Current passing aroundIki island is a combination of the Kuroshio Current and the Taiwan Warm Current, which stems from theEast China Sea. The East China Sea is, in turn, considered to be “an important carbon dioxide sink” [6].
Furthermore, the water temperature around Iki island is lower than that of the low latitude areas of the North
Pacific. As is already known, the concentration of 14C in the atmosphere in the early 1960s was high, andtherefore, it is possible that Iki island corals reflect the changes in 14C concentration in theatmosphere/surface seawater more sensitively than corals in other areas.

Fig. 1. Variations of Δ14C reconstructed from the annual rings in coral coresfrom Guam [1], Ishigaki [2] and Iki Island ([3] and this study).

References[1] A.H. Andrews et al., J. Geophys. Res. Oceans 121 (2016) 6351.
[2] S. Hirabayashi et al., Geochem. Geophys. Geosyst. 18 (2017) 1608.
[3] T. Mitsuguchi et al., Geo-Mar. Lett. 36 (2016) 371.
[4] A. Sakaguchi et al., J. Geophys. Res. Oceans 121 (2015) 4.
[5] M. Stuiver and H. A. Polach, Radiocarbon 19 (1977) 355.
[6] C.M. Tseng et al., Geophys. Res. Lett. 38 (2011) L24609.

13

3.3

Regional dependences of 10Be and 36Cl concentrations in rainwater

Y. Ochiai, K. Sasa, Y. Tosaki1, T. Matsunaka2, T. Takahashi, M. Matsumura, K. Sueki
This study focused on 10Be (half-life = 1.36 × 106 years) and 36Cl (half-life = 3.01 × 105 years), which areproduced in the upper atmosphere by reactions between cosmic rays and elements in the atmosphere (e.g.
16O(p, X)10Be or 40Ar(n, X)36Cl). The 10Be and 36Cl concentrations in rainwater were measured at the Pacificside and the Sea of Japan side, to discuss the regional dependencies of seasonal variation.
We have collected monthly rainwater samples in Tsukuba city, Ibaraki (36°06’N, 140°06’W) since April
2004 and in Nomi city, Ishikawa (36°25’N, 136°32’W) since July 2017. In this report, 10Be and 36Cl
concentrations were analyzed after 2017. Added 0.5 mg of Be carrier, Be2+ and Cl-, which are chemical
forms of Be and Cl in the rainwater samples, were extracted by an ion-exchange method. Be2+ was
precipitated as Be(OH)2 with 15 M NH4OH and converted to BeO by heating in an electric furnace at 850 °C.
Cl- was precipitated as AgCl with 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
10

Be/Be < 1.0 × 10-15 and 36Cl/Cl < 3 × 10-15, and theprecision for both 10Be and 36Cl analysis is ~2%. The
measurement values were corrected with KN
standards prepared by Dr. K. Nishiizumi [2, 3].
Figure 1 shows temporal variations of the (a) 10Be
and (b) 36Cl concentrations in rainwater at Tsukuba
and Nomi. The 36Cl concentration in September andOctober 2017 at Nomi could not be analyzed due to asmall amount of precipitation and the

10

Beconcentration in September 2018 at Tsukuba could
not be quantified because of experimental failure. The
10

Be concentrations ranged from (6.6 ± 0.3) × 106 to(5.9 ± 0.6) × 107 atoms L-1 and from (1.9 ± 0.1) × 106
to (4.7 ± 1.2) × 107 atoms L-1 at Tsukuba and Nomi,
respectively. The 36Cl concentrations ranged from (1.5
± 0.7) × 105 to (2.0 ± 0.1) × 106 atoms L-1 and from
(1.2 ± 0.7) × 105 to (2.6 ± 0.7) × 106 atoms L-1 at
Tsukuba and Nomi, respectively. The concentrationsat Tsukuba and Nomi had poor correlation (10Be;
correlation coefficient r = 0.3, p < 0.2, 36Cl; r = 0.2, p

Fig. 1. Temporal variations of 10Be and 36Cl

< 0.6), therefore it was confirmed that the variations

concentration in rainwater at Tsukuba and Nomi.

of 10Be and 36Cl concentration had different trend

1

Geological Survey of Japan, AIST, 2 Kanazawa University

14

between the Pacific side and Sea of Japan side.
Figure 2 gives comparisons of the seasonalvariation of (a) 10Be and (b) 36Cl concentrations
between Tsukuba and Nomi. The monthly averages of
10

Be and 36Cl concentration were calculated. It wasnoted that the concentrations at Tsukuba were basedon the data after April 2004 [2]. In terms of Nomi, thevariation of 10Be had a similar trend with Tsukuba insummer while the 10Be concentration was higher than
Tsukuba in winter. The strong north-west wind blows
down around the Sea of Japan side in winter, whichtransports much 7Be from the Arctic region [3]because the production rates of 7Be in the polar
regions are higher than in mid-latitude [4]. Also 10Be
is produced much in polar atmosphere, hence, thestrong wind contain huge 10Be, which makes high10

Be concentration in rainwater at Nomi. The

concentration of 36Cl in winter was also higher than insummer at Nomi, corresponding to the large 36Cl
production in the polar regions [4]. In contrast, at

Fig. 2. Seasonal variations of 10Be and 36Cl

Tsukuba, 10Be and 36Cl concentration increased inconcentration at Tsukuba and Nomi.

mid-spring. The strong stratosphere-troposphereexchange occurs around Japan in spring due to the westerly wind. The air mass that has a high concentrationof 10Be or 36Cl in the stratosphere is easy to be transported to the boundary layer. Therefore, a highconcentrations of 10Be and 36Cl were observed in rainwater at Tsukuba. A similar trend of 10Be was reported
on the Pacific side (e.g. [5]).
References[1] K. Sasa et al., Nucl. Instr. Meth. Phys. Res. B 437 (2018) 98.
[2] Y. Ochiai, Master Thesis (2020).
[3] M. Yamamoto et al., J. Environ. Radioactiv. 86 (2006) 110.
[4] J. Masarik and J. Beer., J. Geophys. Res-Atmos. 114 (D11) (2009) D11103.
[5] T. Yamagata et al., Nucl. Instr. Meth. Phys. Res. B 455 (2019) 265.

15

3.4

The Performance of Iodine-129 AMS measurements at the University ofTsukuba in FY 2019

M. Matsumura, K. Sasa, T. Takahashi, Y. Ochiai, T. Matsunaka1, H. Yokoyama, Y. GAO, M. Hashimoto,
A. Sakaguchi, K. Sueki
This report focuses on the performance of 129I measurement by accelerator mass spectrometry (AMS)
for the development of the standard reference materials (STD) of 129I in the near future. Details of the 129I
AMS measurements were shown in the references [1-3].
From April 2019 to March 2020, we measured 257 samples of 129I, the details of which are shown in
Fig. 1. The test samples were chosen from environmental materials such as sea, rain, and river water, as well
as soil and coral. Figure 2 shows the measured values of carrier-reagent blanks. The machine background isestimated to be on the order of 10−15 in the 129I/127I ratio, which is sufficiently lower than the backgroundlevel of the ratio of 2 × 10−14 for ”Old Iodine” provided from DeepWater. However, sometimes, the measured
129 127

I/ I values in blanks ranged over ten times higher than 2 × 10−14. One of the causes for this might be thememory effect [3,4]. The rise in blank values in 2018 and 2019 is most likely to be caused by this memory
effect.

MEASURED 129I/127I (×10-14)

100.0

10.0

2×10-14
1.0

2016

2017

2018

2019

2020

0.1

Fig. 1. Details of measured 129I
by the AMS system in fiscal
2019.

0

10

20
30
40
RUN NUMBER (2016/4-2020/3)

50

60

70

Fig. 2. 129I/127I ratios in blanks.

Figure 3 shows the results of measurement for JAEA 1-1, 2-1, 3-1 STD samples [5] provided by Japan
Atomic Energy Agency (JAEA). They were normalized by using Purdue-2 STD (Z94-0596) with an 129I/127I
ratio of 6.54 × 10−11 in the measurement [6] (the value was revised in 2014 [7]), which was provided by the
Purdue Rare Isotope Measurement Laboratory (PRIME Lab) at Purdue University, USA. The nominal
129 127

I/ I ratios are 3.948× 10−11, 2.406× 10−11, and 5.05× 10−12 for JAEA 1-1, JAEA 2-1, and JAEA 3-1,

respectively. However, the normalized ratios are greater than the nominal values by factors of, on the average,
1.38, 1.39, and 1.40 for JAEA 1-1, 2-1, and 3-1, respectively. These results are similar to those obtained at
the Micro Analysis Laboratory, Tandem Accelerator, the University of Tokyo (MALT), Tokyo, Japan [5].
1Kanazawa University

16

JAEA1-1 (39.48×10 -12)60

35
129I/127I [×10-12]

129I/127I [×10-12]

50
40
30
20
10

30
25
20
15
10
5

0
0

2

4

6

8

0

10

0

RUN NUMBER

2

4

6

8

10

RUN NUMBER

JAEA3-1 (5.05×10 -12)10

129I/127I [×10-12]

JAEA2-1 (24.06×10 -12)40

1904MT

8

1906MT

6

2001MT
1904MTnormalized

4

1906MTnormalized

2

2001MTnormalized

0
0

2

4

6

8

10

RUN NUMBER

Fig. 3. Measured 129I/127I ratios for the JAEA-STD samples. The measurement time for each run
was 2min.

This work was supported by JSPS KAKENHI Grant Numbers 15H02340 and 19H04252.

References[1] K. Sasa et al., Nucl. Instrum. Meth. Phys. Res. B 437 (2018) 98.
[2] M. Matsumura et al., UTTAC Annual Report 2016 (2017) 25.
[3] M. Matsumura et al., UTTAC Annual Report 2018 (2019) 27.
[4] S. Xu et al., Nucl. Instrum. Meth. Phys. Res. B 438 (2019) 96.
[5] T. Suzuki, (JAEA), Private communication.
[6] P. Sharma et al., Nucl. Instrum. Meth. Phys. Res. B 123 (1997) 347.
[7] M. Caffee, (Purdue University), Private communication (2014).

17

3.5

Anthropogenic iodine-129 depositions at the Japan Sea and Pacific sidesof the archipelago, during 2017-2018

T. Matsunaka1, S. Nagao1, S. Ochiai1, T. Takahashi, M. Matsumura, K. Sueki, K. Sasa
The investigation of water dynamics change in the Japan Sea caused by the recent global warming isessential for forecasting the response of ocean circulation with climate change. Anthropogenic 129I (T1/2 =15.7 million years) produced from the thermal neutron fission, is dominated by release from nuclear fuelreprocessing plants in the Europe and supplied at the Japan Sea via atmospheric deposition and surface
runoff. The long-lived 129I is expected as an oceanic tracer of surface and vertical circulations in the Japan
Sea. This study aimed to illuminate the atmospheric deposition flux of 129I in the Japan Sea through themonthly monitoring of 129I in precipitation at Nomi located in middle area of the Japan Sea side of thearchipelago during 2017−2018, by contrasting with the 129I depositions in Tsukuba (Pacific side) about 300
km ESE of Nomi and Hirosaki (Japan Sea side) [1] about 600 km NE of Nomi.
Rain water samples were collected at each station in Nomi and Tsukuba cities using a funnel placed on
the buildings of Low Level Radioactivity Laboratory (Kanazawa University) and Tandem Accelerator
Complex (University of Tsukuba) on a monthly basis from July 2017 to December 2018. After adding 1 mg
of iodine carrier (Woodward old iodine) with an 129I/127I ratio of 1.5 × 10–14 to the filtered 200–500 ml
rainwater sample, the iodine was isolated by solvent extraction with CCl4. The purified iodide was
precipitated as AgI by adding AgNO3. The AgI precipitate was then washed with NH4OH and ultra-purewater, and was dried and loaded into an Al holder with Nb powder. The 129I/127I ratio of the AgI targets wasmeasured using the accelerator mass spectrometry (AMS) system at the Tandem Accelerator Complex. A
terminal voltage of 5 MV and a charge state of 5+ were chosen for acceleration and detection. The
measurement ratios were normalized against the Purdue-1 reference material, which had an 129I/127I ratio of
8.37 × 10–12 and was obtained from the Purdue University, USA. Stable iodine (127I) in the rainwater wasmeasured by an inductively coupled plasma–mass spectrometry (ICP–MS). The original 129I/127I ratios and129

I concentrations in the rainwater were calculated using 129I/127I ratio from AMS and 127I concentrationfrom ICP-MS.
The overall dissolved 129I concentrations in rainwater varied from 18.3 to 326 nBq L–1 (mean 129 nBq
L–1) at Nomi and from 32.7 to 223 nBq L–1 (mean 134 nBq L–1) at Tsukuba. Mean monthly deposition fluxesof 129I during 2017–2018 were in the range 0.144–1.73 µBq m–2 day–1 at two sites (mean 0.834 µBq m–2
day–1 at Nomi and 0.488 µBq m–2 day–1 at Tsukuba, Fig. 1), about one-third to one-half of the mean values
observed at Hirosaki (1.28 µBq m–2 day–1) [1] located 600 km NE of Nomi and 500 km N of Tsukuba. Clear
seasonal variations of 129I depositions were found at the Japan Sea side (Nomi and Hirosaki), with the higher
levels being recorded in winter (November to February). These latitude and seasonal dependences revealed
that the deposited 129I at the Japan Sea was mainly transported by the prevailing northwesterly wintermonsoon from higher latitude area of the North Hemisphere.

1

Kanazawa University

18

MonthFig. 1. Mean monthly depositions of 129I at the Japan Sea side (Nomi) and Pacific side (Tsukuba)
during 2017-2018 contrasting with the 129I deposition at Hirosaki during 2012-2015 [1].
Reference[1] Hasegawa et al., Journal of Environmental Radioactivity 171 (2017) 65.

19

4.
BEAM AND ISOTOPE APPLICATIONSMicro-beam line for materials analysis (front left)

4.1

Vacancy-type defects in Mg implanted GaN studied by positronannihilation spectroscopy

A. Uedono, M. Dickmann1, W. Egger1, C. Hugenschmidt2, S. Ishibashi3, S. F. Chichibu4
GaN has been studied extensively as next generation power semiconductors [1]. In device structure
fabrication, controlled impurity doping in a selective area is essential. Ion implantation is the mostcommonly used technique to control carrier concentrations. A drawback of ion implantation is theintroduction of defects. Because the mechanisms that cause damage during GaN ion implantation and thedamage recovery processes are complicated [2], controlling damage during and after ion implantation is a
key for the reduction of residual defects in GaN. In the present study, we report the annealing properties ofvacancies in Mg-implanted GaN using monoenergetic positron beams [3].
Mg+ ions were implanted into GaN(0001) with energies of 20 to 430 keV to obtain 0.5-μm-deep box
profiles with Mg concentrations [Mg] of 1×1017, 1×1018,
and 1×1019 cm−3. All samples were annealed attemperatures between 1000°C and 1300°C (5 min) inflowing N2 gas at atmospheric pressure. Figure 1 shows the
S values of Mg-implanted GaN with a Mg concentration of
1×1017, 1×1018, and 1×1019 cm−3 after annealing at 1300°C
as a function of the incident positron energy E. The results
for the as-implanted sample with [Mg]= 1×1017 cm−3 arealso shown. The S value corresponding to positronannihilation in HVPE-GaN was reported to be 0.441, andthis value corresponds to positron annihilation in defectfree GaN. For the as-implanted sample, the measured S
values were larger than this value, suggesting positron
trapping by vacancy-type defects introduced by ion
implantation. The solid curves in Fig. 1 are fits to theexperimental data.

Fig. 1. S parameters as a function of theincident positron energy E for Mg-implanted
GaN annealed at 1300°C with [Mg]=1×1017,
1×1018, and 1×1019 cm−3.

Figure 2 shows the derived depth distributions of S from the analysis. For the as-implanted sample, thedamaged region was introduced up to a depth 1000 nm, and this region was deeper than the block profile ofMg (0‒500 nm). This discrepancy was due to defect introduction by Mg implanted below 500 nm and thehigh sensitivity of positrons to vacancy-type defects. After annealing at 1300°C, although the S value below
400 nm decreased, the value at 50−500 nm increased, suggesting the agglomeration of vacancy-type defects
in the region with high [Mg].
1

Universität der Bundeswehr München
Technische Universität München
3
National Institute of Advanced Industrial Science and Technology (AIST)
4
Tohoku University
220

Fig. 2. Depth distributions of S for Mg-implanted
GaN annealed at 1300°C with [Mg]=1×1017,
1×1018, and 1×1019 cm−3. The result for the as-

Fig. 3. Annealing behaviors of S, lifetimes (τi),

implanted sample ([Mg]=1×1017 cm−3) was also

and corresponding relative intensities (Ii) for

shown.

Mg-implanted GaN with [Mg]=1×1019 cm‒3.

For the samples with [Mg]=1×1019 cm−3, the lifetime spectra of positrons were measured, and theobtained spectra were decomposed into one or three components. Figure 3 shows the annealing behaviorsof S, τi and Ii measured at E = 8 keV, where τi and Ii show i-th positron lifetime and corresponding intensity.
The lifetime spectra for the as-implanted sample and the one annealed at 1300°C were analyzed assuming
a one-annihilation mode.

The observed increase in S after annealing at 1000°C was due to the formationof vacancy clusters. The decrease in the S value started above 1100°C, which was due to the activation ofMg, and the resultant change in the charge state of vacancy-type defects. For the as-implanted sample, thelifetime of positrons was obtained as 248±1 ps. Using the computer simulation, the positron lifetimes for
Ga-vacancy (VGa), divacancy (VGaVN), (VGaVN)2, (VGaVN)3 were obtained to be 239, 246, 296, and 330 ps,
respectively. Thus, for the as-implanted samples, the major defect species was identified as Ga-vacancy(VGa) related defects such as VGaVN and/or their complexes with impurities. For the sample annealed at
1000°C, the second annihilation mode can be attributed to the trapping of positrons by vacancy clusters suchas (VGaVN)3. The third lifetime was obtained at 510±60 ps. A similarly long positron lifetime was observedfor plastically deformed GaN [4], attributing to positron trapping by large vacancy clusters or microvoids.
The present research showed that the positron annihilation technique is suited to study the vacancies in
GaN. Knowledge on the annealing behaviors of vacancy-type defects is useful for optimizing the process of
fabricating p-type GaN by using ion implantation.
References[1] H. Amano et al., J. Phys. D: Appl. Phys. 51 (2018) 163001.
[2] S. O. Kucheyev et al., Mat. Sci. Eng. R-Rep. 33 (2001) 51.
[3] A. Uedono et al., Phys. Stat. Sol. B 256 (2019) 1900104.
[4] A. Uedono et al., J. Appl. Phys. 114 (2013) 084506.

21

4.2

Microscopic 3-dimensional mapping of hydrogen bubbles in Al by elastic
recoil detection analysis under transmission geometry

A. Yamazaki, K. Sasa, S. Tomita, S. Ishii, H. Naramoto, M. Sataka, H. Kudo, G. Itoh1, M. Ohkubo2
Hydrogen in Al typically becomes gas bubbles which may cause brittleness of Al-based structural
materials since the gas bubble behaves effectively like lattice defects or solid solutions. To understandmechanical influence caused by hydrogen in Al and Al alloys, it is crucial to establish a method for observing
3-dimensional distributions of hydrogen in materials.
In response to such technical requirement, we have demonstrated to measure microscopic 3-dimensional
distribution of plasma-charged hydrogen in polycrystalline Al. The measurements have been carried out
nondestructively by using elastic recoil detection analysis under transmission geometry (T-ERDA) of acollimated 8 MeV 4He2+ beam. The recoil cross section as large as 2×103 mb/sr due to the nuclear elastic
collision allowed observation of the spatial distribution of hydrogen in the Al sample of 80 μm thickness.

(80 μm thick Al sample)
8 MeV He
3.75 MeV H
0-enegy H
Surface(0 depth)

Detector
He range (43 μm)
Max. detectable depth (30 μm)

Fig. 1. Schematic diagram of the present T-ERDA.
Deeper H recoil results in lower exit energy.

Fig. 2. Optical photograph of the surface of the
Al sample placed on the right. The Al-coatedmylar film placed on the left is for reference ofa hydrogen-containing sample. The square
marked in yellow shows the 250×250 μm2 area
analyzed by T-ERDA.

Fig. 3. T-ERDA energy spectrum measured for the
250×250 μm2 area on the Al sample. The scale of depth
where the H recoil occurred is indicated. The dashed line
shows the assumed background of 192 counts.

1
2

Ibaraki University
AIST

22

The distribution maps of hydrogen (Fig. 4) clearly visualize 3D hydrogen bubbles of 10-20 μm diameterin the surface layer of about 12 μm thickness. The critical concentration of hydrogen minimally needed for
growth of the hydrogen bubble of ten-μm size has been determined to be 1:6×1020 cm−3. T-ERDA combinedwith nuclear elastic scattering thus provides 3D data from which we obtain direct information about
microscopic behavior of hydrogen in materials.

Fig. 4. 3-dimensional mapping of plasma-charged hydrogen in the Al sample of 80 μm thickness,shown for the 6 slices, (a)−(f), of 12 μm depth. The scanned area is 250×250 μm2 which is marked
in yellow in Fig. 2. The lateral resolution is 3.5 μm and the depth resolution is ~1.2 μm, see text.
Note that the color scale is logarithmic and the pixels of zero count are shown in black. The average
He2+ beam current was 80 pA and the measurement time was about 1 hour.

Notably, a triangle-like distribution of hydrogen is seen near the left-bottom corners of the 6 images inFig. 4. Since the Al foil is polycrystalline, such an anisotropic distribution in a ten-μm space is not expected
to arise from local lattice disorder in Al, which is in contrast to the lattice-dependent precipitation of
implanted atoms in a single crystal [2]. A possible origin might be the growth of tetrahedral AlH3 [3].

References[1] A. Yamazaki et al., AIP Advances 9 (2019) 105111.
[2] For example, M. Ohkubo and N. Suzuki, Philos. Mag. Lett. 57 (1988) 261.
[3] G. Itoh, et al., Keikinzoku (Light metals) 40 (1990) 36 (in Japanese).

23

4.3

Depth resolution of hydrogen distribution in Al measured with elastic
recoil detection analysis under transmission geometry

A. Yamazaki, K. Sasa, S. Tomita, S. Ishii, H. Naramoto, M. Sataka, H. Kudo
In a previous study, we have measured 3D hydrogen distribution in an H-charged Al foil of 80 μm
thickness applying elastic recoil detection analysis under transmission geometry (T-ERDA) using 8-MeV
He2+ [1]. In this case, the depth resolution for hydrogen at the Al surface was ~1.2 μm which was estimatedfrom the width of the spectrum peak of hydrogen localized near the Al surface. In this case, the depth
resolution results from the energy straggling of recoil H in the outgoing path through the Al foil. However,the depth resolution at a given depth should result from straggling of both incident He and recoil H. For
wide application of T-ERDA in future, we need to investigate how the depth resolution varies in the depth
range of interest.
Test sample
Recoil H

10-MeV He2+

Detector
50-μm thick Al

Fig. 1. Schematic diagram of the test sample consisting of a layered structure of four sheets of 1.2 μm
thick PPS (blue) and three sheets of 10 μm thick Al (gray), which are mounted on Al of 50 μm thickness.

For this purpose, we have prepared a multilayered
sample of 1.2-μm thick polyphenylene sulfide (PPS) and10-μm thick Al, which were mounted on an Al foil of 50
μm thickness, as shown in Fig. 1. In the experiments, 10
MeV He2+ was incident on the sample and the recoil H
from PPS was energy-analyzed with a semiconductor
particle detector.
Figure 2 shows the measured energy spectrum of H
after passing through the sample. The four peaks
correspond to the depths of the PPS layers, as indicatednear the peaks. The peak widths result from energy
straggling of incident He and recoil H. On the other hand,the peak areas result not only from energy straggling
which might deflect the recoil H away without entering thedetector, but also from energy dependence of the recoilcross section for H. None of these peaks have a flat top,which indicates only minor energy losses in the thin PPS
layers. Therefore, the energy difference between the24

Fig. 2. Hydrogen energy spectrum of
measured by T-ERDA. The peaks correspondto the depths of the four PPS layers.

adjacent peaks ΔE is mainly due to the Al thickness of 10 μm. It should be noted that ΔE increases slightly
with increasing the depth, corresponding to larger stopping power of Al for lower-energy H in the present
case. The depth resolution ΔD at a given depth can be estimated from the FWHM value of the spectrum
peak. Hence, we obtain ΔD at depths of 0 (surface), 10, 20 and 30 μm.
The results are shown in Fig. 3. The value of ΔD increases rapidly with increasing the depth beyond 20
μm. It is pointed out that comparison of the peak areas provide effective counting efficiency of recoil H at a given
depth. In the present case, for example, the counting efficiency at 10 μm depth is less than at the surface by ~10%.

Further measurements concerning not only the depth resolution, but also the lateral resolution are now under
way for precise analysis of T-ERDA data, in particular, 3D images of hydrogen distribution.
4.5
4.0

ΔD (μm)

3.5
3.0
2.5
2.0
1.5

0

10

20

30

Depth (μm)

Fig. 3. ΔD vs. depth, determined from the H spectrum shownin Fig. 2. The spline curve was drawn to guide the eye.

Reference[1] A. Yamazaki et al., AIP Advances 9 (2019) 105111.

25

4.4

Trial of 7Li depth profile determination by 7Li(p, α)4He NRA

D. Sekiba, Y. Sugisawa, N. Kishi
Development of all-solid lithium ion battery has been required from the viewpoint of large and safe
electric storage. The most serious problem of all-solid lithium ion battery, that we must overcome, is thecurrent restraint during the discharge. It is widely believed that there is a non-desirable block layer between
the solid-state electrolyte and the anode. At present, we usually use Li3PO4 and LiCoO2 for the electrolyte
and the anode, respectively. The scenario, that there could be a block layer against the Li ion migration,
remains a matter of speculation among the engineers in this field. In order to examine the scenario, we areintending to measure the Li depth profile non-destructively during the device operations. For the first step,
we made 7Li(p, α)4He NRA measurements [1] to estimate the depth resolution of this technique, which
depends considerably on the experimental setup.
Figure 1 shows a schematic of the sample prepared for thepresent study. The three Li3PO4 layers of 100 nm thickness are
separated by the two Au layers of 100 nm thickness, and they
are deposited on the substrate of ordinary quartz. The topmost
100 nm thick Au layer is a cap to suppress the oxidation. The
NRA measurements were carried out using the conventional
RBS/ERDA chamber at D-course of 1 MV Tandetron in
UTTAC [2]. H− ions extracted from the sputtering ion source
were charge-exchanged and accelerated up to 1.5 MeV, andused as a probe beam after shaped as 1×1 mm2 by a double slit

Fig. 1. Schematic of the sample structure.

system. The emitted α particles (~ 7.8 MeV) were detected by a Si surface barrier detector placed at θ’=150owith respect to the beam direction, as schematically shown in Fig. 2. The angle θ between the detection
direction and the surface normal is anexperimental parameter mainly to change thelength of the outgoing path of the emitted α.
Figure 3 shows the NRA spectra obtained at(a) θ=75o and (b) 80o. In both spectra, we clearly
see three peaks corresponding to the 7Li (p, α)
4

He reaction in the three Li3PO4 layers as

Fig. 2. Schematic of the experimental setup.

annotated in Fig. 1. First of all, we concluded
that with this technique 100 nm or better depth resolution is achieved. This conclusion was also supported
by using a similar sample of 50 nm layer thickness, instead of 100 nm layer thickness. At θ=80o, we noticethat the peak width of the third layer is considerably deformed probably due to the energy struggling of theemitted α particles, nevertheless the sufficient separation between the two peaks corresponding to the first
and the second layers might provide local but valuable information. These results seem helpful to choose
the NRA depth resolution needed to investigate the depth range of interest in the sample.

26

Apart from the intense three peaks due to the first, second and third Li3PO4 layers, we see weak α signals
in the energy range of 2400 ~ 2600 channels in Fig. 3 (a) and (b). While the origin of these signals is so far
not clear, we guess that Li migrates into the Au cap layer. In the next experiment, we are intending to use
Ni instead of Au because Li does not make any alloy with Ni.
As conclusion, we confirmed that non-destructive NRA is useful to investigate the real devices currently
developed in many facilities all over the world because the all-solid Li ion batteries usually have ~100 nm
thickness for the anode and cathode and several mm thickness for electrolyte. The Li profile measurements
during the device operation are also promising with this method.
We thank Prof. T. Hitosugi, Dr. R. Shimizu and Mr. S. Kobayashi of Tokyo Institute of Technology for
their sample preparations and critical discussions.

Fig. 3. NRA spectra taken on the multi-layered sample with the setup of (a) θ=75o and (b) 80o.
References[1] J. Räisänen, Nucl. Instr. Meth. Phys. Res. B 66 (1992) 107.
[2] D. Sekiba, et al., Diamond & Related Materials 27-28 (2012) 60.

27

4.5

Depth profiling of lithium by use of TOF-E telescope ERDA

Y. Sugisawa, D. Sekiba, I. Harayama
Li-ion batteries are widely applied to various portable devices and have distinct potential as powersources. However, the risk of combustibility of organic solvent has limited its application. All-solid-state
Li-ion batteries have been developed to remove this limit by using non-combustible electrolyte [1]. Apartfrom the safety, all-solid-state Li-ion battery would enable us to obtain the capacity increase or microfabrication. For the realization of such a battery, the poor Li conductivity at the electrode-electrolyte
interface should be improved [2]. Hence, it is important to understand the dynamic transport of Li at theelectrode-electrolyte interface of Li-ion batteries. Time of flight-energy telescope elastic recoil detection
analysis (TOF-E telescope ERDA) is an effective technique for quantitative depth profiling of light elementsin thin films [3, 4]. This technique can be also applied to the analysis of the electrode-electrolyte interfaceof Li-ion batteries. In our present work, we observed Li in a Li(CoNi)O2 film deposited on Al2O3, which istypically used as a positive electrode, as the first step for observation of the electrode-electrolyte interface.
The TOF-E telescope ERDA measurement was performed at 1 MV Tandetron in UTTAC. Figure 1 showsthe experimental setup of the scattering chamber and TOF tube. The system consists of two time-detectors(T1 and T2) each equipped with a micro-channel plate (MCP) and a particle detector (SSD) of 300 mm2
sensitive area. T1 and T2 generate the start and stop triggers in the TOF measurement, respectively, while
SSD determines the kinematic energy of the recoils. T1 is placed at 376 mm from the sample and the distance
between the two time-detectors is 640 mm. The SSD is placed at 1093 mm from the sample. We can adjust
the solid angle of the measurement system by the aperture at T1. The aperture with the diameter of 2.5 mm
is usually set to limit the solid angle to be smaller than that defined by the sensitive area of SSD. In thepresent study, the typical incident beam was 4 MeV 35Cl4+ and the beam size was shaped as 1 × 1 mm2 witha slit system. The beam incident angle on the sample was usually 75º from the surface normal. The recoiland backscattering angles are 30º

HERDA chamber
SSD

and 150º from the beam incidence
direction, respectively.

T2
93
10

Figure 2 shows the twodimensional histograms of the

SSD for RBS

TOF-E telescope ERDA taken for
the Li(CoNi)O2 film deposited on

FC

the

Al2O3

substrate.

Theassignment of each element isnotated in Fig. 2. 7Li, O, and Al are
clearly seen, while Co and Ni are

500 mmChopper

T1

6
37

30°

0
64

TOF tubeFC

slit

SSD for RBS
FC

90° sector magnet

SSD for ERDA

ChopperFig. 1. Experimental setup of our scattering chamber and TOF tube at
1 MV Tandetron in UTTAC.

not distinguished. In addition, we
can see slight signals under the 7Li curve, which are assigned to the recoils of 6Li. The mass resolution Δmis expressed by

28

∆𝑚

𝑚

∆

∆

,

where m, E, t, ΔE, and Δt are the atomic mass, recoil energy, energy resolution, and time resolution of recoils,
respectively. The mass resolution for 7Li is calculated as 0.6 u, suggesting that our measurement system canseparate 7Li and 6Li.
We obtained the depth profiles of each element in the film as shown in Fig. 3 by converting the TOF todepth by using the stopping power. The relatively weak 7Li yield is indicated on the expanded right scale.
The Li(CoNi)O2 film was observed at 〜30 nm in Fig. 3. The O/CoNi and Li/ CoNi ratios in the film
estimated from the depth profiles are 1.8 and 0.2, respectively. The former, approximately equal to 2,
corresponds to the stoichiometric ratio. However, the latter ratio 0.2 largely deviates from the stoichiometricratio of Li/CoNi=1. This might imply that signal loss in our TOF measurement system is significant for thedetection of Li. In the future work, we investigate the cause of signal loss and improve the measurement
system.
.

Co&Ni
Al
7

6

Li
Li

Cl
O

Fig. 3. Depth profile of each element in the
Li(CoNi)O2 film deposited on the Al2O3
substrate.

Fig. 2. Two-dimensional histograms of the TOF-E
telescope ERDA taken on the Li(CoNi)O2 film
deposited on the Al2O3 substrate.

References[1] Y. Sun et al., Chem. Mater. 29 (2017) 5858.
[2] T. Minato and T. Abe, Progress in Surface Science 92 (2017) 240.
[3] M. Chicoine et al., Nucl. Instr. Meth. Phys. Res. B 406 (2017) 112.
[4] B. Brijs et al., Microelectron. Eng. 80 (2005) 106.

29

4.6

High magnetic field Mössbauer study on an antiferromagnetic layered
FeNi nitride, FeNiN

S. Goto1, H. Yanagihara, E. Kita2
Fe nitrides show various physical, electronic, and chemical properties where nitrogen atoms have played
an important role on their electronic structures. For example, a larger magnetic moment than that of α-Fe
has been reported on Fe16N2. With increasing concentration of nitrogen, Fe nitrides change from Fe4N, Fe3N,
to Fe2N. Their structures are a cubic perovskite for Fe4N and a hexagonal for Fe2-3N, respectively.
Basically in Fe nitrides, nitrogen atoms occupy at interstitial crystallographic sites and basic structure is notdeformed much. It was reported that the increase of nitrogen concentration resulted in the decrease offerromagnetic transition temperature (TC) and TC goes down to room temperature at around Fe2.5N.
Fe2N has an orthorhombic structure and by substituting Fe atoms by Ni atoms, a face centered tetragonal
FeNiN is formed where Fe and Ni layers are interlaminated along the z-direction (see Fig. 1) [1]. As seen in Fig.
1, nitrogen atoms are only located on Fe layers at interstitial sites. This structure has been utilized tosynthesize an L10-FeNi alloy, a viable candidate of high magnetic anisotropy material, by removing nitrogenatoms from FeNiN [2]. For this purpose, the uniform high grade FeNi particles are required and basic
properties of FeNiN as a starting material should be well understood [5]. We have performed Mössbauer
study on FeNiN at low temperatures with/without an external magnetic field to understand the magnetismof FeNiN,
The FeNiN powder samples were synthesized by a gas phase nitridation of FeNi powders [2, 5]. A layer
structure was confirmed with an X-ray diffraction study [5]. 57Fe Möessbauer spectroscopy was performed
at a transmission setup with a constant acceleration mode. A γ-ray source of 57Co radio isotope with 1.85
GBq was used. An experimental setup wascomposed of a commercial linear motion driver
Ni layer(WissEL) and a conventional data acquisition
system. An external magnetic field up to 5 T wasapplied parallel to the γ-ray direction by asuperconducting

magnet[3].

Fe and N
layer

Measurement

temperatures were room temperature, 77 K and 10
K. Data were analyzed with a commercial fitting
Ni layersoftware [4]. The powder sample with 10 mg was
mixed with BN powder and the mixture was set
into a sample holder made of a 1 mm thickness
lead plate with a 10 mm diameter hole where theγ-ray passed through.

Fig. 1. Unit cell of FeNiN. Ni an Fe atoms form a facecentered tetragonal structure (drawn with VESTA).

1 DENSO Corporation
2 NIT Ibaraki College

30

Figure 2 shows Mössbauer spectra for the FeNiN powder. The room temperature spectrum is composedof a set of a singlet and a doublet with small area, and there is no trace of magnetic sextets. This clearlyshows that FeNiN is paramagnetic at room temperature. The area for the double is about 5 % and most Fe
atoms are located at high symmetric positions proofing a high quality of sample. At low temperatures,
magneticallysplit

spectrawereobserved at 77 K and 10 K. It is simply
concluded that the magnetic transition
temperature of FeNiN is noticed
between room temperature and 77 K.
Actually, the transition temperature
was determined at 178 K by a magnetic
susceptibility measurement [5]. To
understand the sort of magnetism at the
specific temperature, ferromagnetismor antiferromagnetism, an in-field
Mössbauer measurement is effective.
The spectra recorded at 10 K with andwithout external magnetic fields areshown in Fig. 2 (c) and (d). An intensity
ratio of 2nd and 5th peaks to 3rd and4th peaks, I25/I34, for the zero-field
spectrum was close to 2, the value for
the

case

of

randomly

orientedmagnetization, and the value for the infield spectrum was not zero but 4. This
result indicates that magnetic moments
Fig. 2. Mössbauer spectra of FeNiN powder recorded (a) at room
temperature, (b) at 77 K with Hex= 5 T, (c) at 10 K with Hex= 5 T
and (d) at 10 K without Hex. Experimental data and the results offitting were depicted by open circles and solid lines, respectively.

arealignedinthedirection

perpendicular to the magnetic field of 5
T. It supports that the sort of magnetismof FeNiN at low temperature isantiferromagnetism [5].

References[1] J. B. Goodenough et al., J. Appl. Phys. 31 (5) (1960) S342.
[2] S. Goto et al. Scientific Reports 7 (2017) 13216.
[3] SpectroMAG, Oxford Instruments, London.
[4] MossWinn 4.0, Z. Klencsár, Hyperfine Interact. 217 (2013) 117.
[5] S. Goto et al., ACS Appl. NANO Mater. 2(11) (2019) 6909, and its supporting information,
https://pubs.acs.org/doi/suppl/10.1021/acsanm.9b01405/suppl_file/an9b01405_si_001.pdf

31

4.7 Simultaneous detection of light elements under non-Rutherford scattering
H. Naramoto, M. Sataka, H. Kudo, K. Sasa
Our ion beam analysis system is equipped with the high-precision rotational systems for samplealignment and sample-detector arrangement. The rotational systems are required to be calibrated referringto the beam direction which depends on the beam transport carried out every time for individual experiments.
We have been concerned with the sensitive analysis of low Z elements, especially hydrogen, employing the
non-Rutherford scattering process [1], and the angle calibration method has been developed based on theelastic recoil process under transmission using the model film of Mylar(0.9μm)/Al(8μm)/Mylar(0.9μm)/
Al(80μm) on a modified sample holder. The angle calibration of sample-detector arrangement system was
performed by evaluating thepeak-energychangeofhydrogen recoil spectra fromthe 1st Mylar layer (thetopmost layer) of the samemodel film [2], which reflects
the relevant collision kinetics
directly. In this report, aredescribed

thecalibration

procedureofsamplealignment system and the
study

of

simultaneous

detectionofhydrogen and oxygen on a 4N
pure Fe film (50µm) surface.

Fig. 1. Transmitted hydrogen recoil spectra at 0° from the model film for nominal
incident angles of 8 MeV 4He2+.
260

Figure 1 shows a set of transmitted hydrogen recoil
spectra at 0° from the model film under different incident
angles of 8 MeV 4He2+ around the surface normal of sample
holder. In this calibration, attention was paid to the recoil
spectra from the 2nd Mylar layer of the model film because
more pronounced peak shift than for the 1st layer can be
expected to occur by reflecting the energy loss of incident
4

He2+ at the inserted Al(8μm) layer. By assuming thesymmetric change of recoil-peak energies with the sample
holder rotation, the surface normal was determined to be+4.09° as illustrated in Fig. 2. The more refined calibration
can be realized by designing a sample holder capable of thein-plane rotation.

32

Peak Position of Recoil Spectra Ch.)

subsequent

-20

250

+4.09º
240

230

220
-10
0
10
20
Incident Angle (Degree)

30

Fig. 2. The surface normal calibration ofsample holder based on transmitted hydrogenrecoil spectra from the 2nd Mylar in Fig. 1.

Following the establishment of angularcalibration method, we have analyzed thepossible contamination of water molecules on the
4N pure Fe film surface in order to obtain theinformation on the origin of background in recoilhydrogen spectra and also on the simultaneous
detection of other low Z elements together withhydrogen on a high Z substrate.
Figure 3 shows three kinds of recoil spectra
at 0º under the normal incidence of 8-10 MeV
4

He2+ onto the 4N pure Fe film. One can see thesensitive detection of hydrogen recoils from thewater molecules just on the 4N pure Fe surface.

Fig. 3. Transmitted recoil spectra at 0º under the normal
incidence of 8-10 MeV 4He2+ ions onto the 4N pure Fe
film. The recoil yields in the spectra are normalized to theaccumulated charge of 10μC.

The features of background spectra are rathersmooth irrespective of the energy change ofincident 4He2+, and it would be easy to subtractsuch smooth backgrounds.
Figure 4 shows backscattering spectra at
168.5° from the same Fe sample, which were
measured for 8, 9, and 10 MeV 4He2+. These
spectra were recorded simultaneously with therecoil spectra shown in Fig. 3. The spectralfeatures are basically smooth, but the appearanceof the sharp peak at 312 Ch. on the smoothbackscattering spectrum can be seen only for 10
4

2+

MeV He . The more distinctive peaking was
confirmed on the oxidized Cu sample (not shown

Fig. 4. Backscattering spectra from the 4N pure Fe film at
168.5º simultaneously taken with those in Fig. 3. The yield
was normalized under the same condition.

for the simplicity), which can be associated with 16O (α, αo) 16O resonant elastic scattering [3].
As suggested above, the combined use of transmission recoiling and resonant elastic backscattering with
8-10 MeV 4He2+ can be beneficial for the simultaneous detection of hydrogen and other low Z elements on
the surface region of substrates with high Coulomb barriers. The process of simultaneous detection can beeffectively applied for the position-sensitive composition analysis by taking advantage of a micro-beamscanning system for high-energy ions [4].
References[1] A. Yamazaki et al., AIP Advances 9 (2019) 105111.
[2] H. Naramoto et al., UTTAC Annual Report 2017, UTTAC-87 (2018) 47.
[3] IBANDL (Ion Beam Analysis Nuclear Data Library). https://www-nds.iaea.org/exfor/ibandl.htm[4] A. Yamazaki et al., Nucl. Instr. Meth. Phys. Res. B 404 (2017) 92.

33

4.8

Recombination effect in the output pulse height of superconducting tunnel
junction for the incidence of keV ionsS. Tomita, S. Shiki1, G. Fujii1, T. Takahashi, K. Sasa, M. Ukibe1
Superconducting tunnel junction (STJ) has a sandwich structure of superconductor-insulatorsuperconductor (SIS) tunnel junctions which enables the detection of low-energy particles through phonon
excitation at the detector surface [1]. The phonons whose energy is greater than 2Δ can subsequently beabsorbed by Cooper pairs, producing a number of quasiparticles which can quantum mechanically tunnel
through the thin insulating barrier. The magnitude of the tunneling current pulse is proportional to thenumber of quasiparticles which is proportional to the energy deposited into the detector by the impacting
particle. Thus, STJ can be used for the energy-sensitive detection of particles, especially keV molecules
which are unable to detect with standard surface-barrier semiconductor detectors. Actually, STJ has beensuccessfully used for detection of X-ray and keV molecules [2]. But, the energy resolution for the detectionof molecules is relatively poor compared to that of X-ray. Even more, it has been reported that there is asignificant pulse height defect for the large molecules [3]. The reason for the difference is not fully
understood yet. The energy loss due to secondary particle emission, such as, secondary ion emission andelectron emission, could be a possible mechanism. Another possibility is the increase of leak current stems
from the infrared light shed on the STJ surface.
To understand the difference in the STJ response of X-ray and ions, we have measured X-ray and ionsin same experimental conditions (temperature, infrared right, electronic noises). The experiments were
performed with double-focusing mass spectrometer (JEOL JMS-600W). The ions generated with electron
impact ionization of air was accelerated with potential difference of 3 kV and the mass analyzed ionsaccording to their mass to charge ratio impinged on the STJ. The size of STJ was 100 μm square with alayer of Nb/Al/AlOx/Al/Nb electrode. The STJ was mounted on 3He cryostat with the base temperature ofabout 300 mK with a blocking filter of infrared light [4]. An X-ray emitter was arranged in parallel to theion beam line so that the STJ can be moved in front of the source to perform X-ray measurement with thesame condition as ion measurements.
The pulse height distributions of the STJ signal of 3keV H+ and N+ are shown in Fig. 1, together withthat of X-ray of Al-Kα (1.486 keV). The small peak located at higher channel corresponds to N22+ ions of
6keV which has the same velocity as 3keV N+. The pulse height is scaled according to the kinetic energy of
impinging particle. The scaled pulse heights of ions are almost the same to that of X-rays, thus, the pulse
height defect due to loss of secondary particle emission is negligible at least in this case. The absolute energy
resolution of an X-ray signal is poorer than that of normal X-ray measurement with protection of infrared
light. Thus, the detector temperature and the amount of infrared right shed on the detector surface seems to
be important for the energy resolution. However, the absolute width of the peak is not the same for the Xray and ions, thus the fluctuation of the leak current is not the main cause of the energy resolution. The pulse

1

National Institute of Advanced Industrial Science and Technology (AIST)

34

height for H+ is higher than that of X-ray or N+. This could be the result of the density effect of excited
particles rather than that of difference in the excitation process of quasi particles. Because the pulse heightof N22+ ion is much lower than the twice of the pulse height of N+ ion, even though both ions have the same
velocity. The relaxation process of their kinetic energy is the same for both cases. This means that density
effect of excited particles, e.g., recombination of quasi particles, may play an important role for the pulse
height defect process.
600

N+/N2+
2
H+
X-ray

500

Yield

400

300

200

100

0
0

50

100

150

200

250

300

350

400

450

500

Pulse height / Energy (arb. unit)

Fig. 1. Pulse height spectra of H+ (3keV) (red line), N+ /N22+ (3keV) (black line), and Al- Kα X-ray (1.486
keV) (blue line). Pulse heights are scaled according to the kinetic energy of the impinging particle.

References[1] P. Lerch and A. Zehnder, in Cryogenic Particle Detection, edited by C. Enss (Springer Berlin Heidelberg,2005), pp. 217.
[2] M. Ohkubo et al., IEEE Transactions on Applied Superconductivity 24 (2014) 1.
[3] S. Tomita et al., Appl. Phys. Lett. 91 (2007) 053507.
[4] S. Shiki, et al, Nucl. Instr. Meth. Phys. Res. A 595 (2008) 391.

35

4.9

Heteroepitaxial growth of thin films of the perovskite oxynitride
CaTaO2N by reactive magnetron sputtering

T. Wakasugi1, Y. Hirose1, Y. Sugisawa, D. Sekiba
Perovskite oxynitrides have been studied because of their visible light driven photocatalytic activity andnovel electronic functions.1 Assessment of the intrinsic physical and/or electrochemical properties ofoxynitrides requires the epitaxial growth of single crystalline films. However, the heteroepitaxy ofperovskite oxynitrides has not yet matured compared to the progress realized in work with perovskite oxides.
Herein, we studied the heteroepitaxial growth of CaTaO2N thin films with (100)pc, (110)pc and (111)pc
crystallographic surface orientations on SrTiO3 substrates (where the subscript pc denotes a pseudo-cubiccell), along with investigations of crystallinity and surface morphology.
CaTaOxNy thin films were deposited by reactive RF magnetron sputtering using a CaTaOx ceramic target.
During the thin film deposition process, the substrate temperature was maintained at 630 °C and Ar and N2
were introduced into the chamber. The total gas pressure and total gas flow rate were set at 0.75 Pa and 20
standard cc·min−1, respectively. The N2 partial pressure, PN2, was varied between 0 and 0.3 Pa to adjust the
N content in the films. The input RF power and the target-substrate distance were set at 100 W and 12 cm,
respectively. The N to Ta ratios (N/Ta) of the thin films were estimated from the N amounts determined byheavy ion elastic recoil detection analysis (ERDA) and the Ta amounts determined by Rutherford
backscattering spectrometry (RBS) with a 38.4 MeV 35Cl beam generated by a 5 MV tandem accelerator(MALT).2 The crystal structures were analyzed using X-ray diffraction (XRD).
Figure 1(a) shows the θ-2θ XRD
patterns obtained from a series of the
CaTaOxNy thin films grown on
SrTiO3 (100) substrates under various
PN2. Each of these patterns confirms
the epitaxial growth of (100)pcoriented perovskite. Nevertheless, theN/Ta ratios vary from 0 to 1 in thepresent range of PN2, as seen in Fig.
1(b). The perovskite structure isevidently kept even in the case of thefilm containing no N (PN2 = 0),
possibly due to the formation of
cation vacancies. Notably, the N/Ta
ratio increases with increasing PN2
and reaches a plateau of the level

1

Fig. 1. (a) The θ-2θ XRD patterns of CaTaOxNy thin films grown on
SrTiO3 (100) under various PN2 (asterisks denote diffraction peaks
from the substrate). (b) N/Ta ratios, (c) full width at half maximum of
the 200 diffraction rocking curves, (d) unit cell volumes based on a
pseudo-cubic approximation, and (e) root mean square roughness
values of films, rRMS, all plotted against PN2.

The University of Tokyo36

approximately equal to 1 at PN2 ≥ 0.075 Pa. This result suggests that the N concentration is self-limited by
crystallization into the perovskite structure. With increasing PN2, the cell volume per formula unit, Vpc, of
the CaTaOxNy thin films increases up to the maximum of 0.0610 nm3 at PN2 = 0.075 Pa, as seen in Fig. 1(c).
This Vpc value is in good agreement with the calculated value for biaxially strained CaTaO2N assuming a
Poisson’s ratio of 0.30 which is a typical value for oxynitrides. Further increase in PN2 causes decrease in
Vpc, suggesting the formation of lattice defects. Figures 1(d) and (e) show the PN2–dependence of the full
width at half maximum of the rocking curve for the 200pc diffraction and the root mean square roughness of
the CaTaOxNy thin film, respectively. In both cases, the measured quantity decreases as PN2 increases from0 to 0.075 Pa, and reach a minimum at PN2 = 0.075 Pa. We speculate that the degradation of crystallinityand volume reduction at PN2 higher than 0.075 Pa originate from slight off-stoichiometry such as excess
nitrogen, which could not be detected by the compositional analysis.
Figure 2(a) presents the θ-2θ XRD
patterns of 20-nm thick CaTaO2N films
grown on the (100), (110) and (111)planes of SrTiO3 substrates, while Figs.
2(b)-(d) are the reciprocal space maps
(RSMs) of these films. Both the XRD
patterns and RSMs confirm the epitaxial
growth of CaTaO2N thin films with thesame orientations (in a pseudo-cubic
approximation) as the substrate surfaces.
The RSMs also indicate that the in-planelattice constants of the CaTaO2N are
locked to those of the SrTiO3 substrates.
Comparing the three RSMs for different
crystallographic orientations leads toconcluding that the (110)pc oriented film isFig. 2. (a) The θ-2θ XRD patterns of 20 nm-thick CaTaO2N thinfilms grown on SrTiO3 (100), (110) and (111) substrates(asterisks denote diffraction peaks from the substrates). (b-d) The
XRD RSMs for the films grown on SrTiO3 (b) (100), (c) (110),and (d) (111) substrates.

more highly crystalline than the films with other orientations, since the films grown on SrTiO3 (100) and(111) substrates generate broader diffraction spots along the in-plane direction than that on the (110)substrate. Because all these films have the same N/Ta ratios within an experimental error, we attribute thisevident variation in crystallinity not to deviations from stoichiometry but rather to reflected symmetry
mismatch between CaTaO2N (orthorhombic) and SrTiO3 (cubic), which results in formation of multiple
domains with different in-plane crystallographic orientations for (100)pc- and (111)pc-oriented thin films.3
References[1] T. Takata et al., Sci. Technol. Adv. Mater. 16 (2015) 033506.
[2] I. Harayama et al., Nucl. Instr. Meth. Phys. Res. B 384 (2016) 61.
[3] T. Wakasugi et al., ACS Omega 5 (2020) 13396.

37

4.10

Electric properties of magnesium titanium oxynitride thin films

A. Ogura, Y. Sugisawa, D. Sekiba, H. Yanagihara
One of the ways to evolve the spintronics is to improve the performance of magnetic tunnel junctions(MTJs). A device structure of conventional MTJs is a tri-layer system composed of two ferromagnetic metal
layers/electrodes separated by a very thin non-magnetic insulator layer/tunneling barrier. As an alternative,
spin-filter devices are proposed, in which the tunneling barrier is ferromagnetic insulator. Ferromagnetic
insulator can be expected to generate highly-spin-polarized tunneling current because the band gaps
dependent on spin sate is much different [1]. Among the various ferromagnetic insulating compounds, spinel
ferrites are promising materials for the tunneling barrier of the spin-filter devices because of the high Curie
temperature and high electric resistivity. Some spin-filter devices with the spinel ferrite barrier have beenreported, however, the observed magnetoresistance ratios are very small [2]. In order to realize ideal spinfilter devices with spinel ferrites, we have to carefully control the film growth process and also to explore
appropriate buffer layers at the first onset. In this case, the buffer layer works not only as a template for theepitaxial growth of upper layer/barrier but also as a bottom electrode of MTJs. Since non-negligible amountof defects such as anti-phase boundaries occur at the initial growth of spinel ferrite thin films on (001)-planeof cubic system with a lattice constant approximately half of the spinel like MgO [3], we need to findconductive compounds with the lattice constant comparable to that of the spinel ferrites. As a candidate, we
focused on magnesium titanium oxynitrides (MTON). We attempted to grow epitaxial MTON films. In thisreport, we show how the growth condition affects the composition, structure, and electric properties.
We grew samples with a reactive magnetron sputtering technique introducing process gases of argon
and/or nitrogen. The sputtering target was MgTi2O4
ceramics and the substrates were single crystal
MgO(001). Crystal structures of the films were
investigated by x-ray diffraction (XRD) technique aswell as in situ reflection high energy electron diffraction(RHHED) images. Composition of the films were
determined by TOF-E telescope ERDA (Elastic Recoil
Detection Analysis) at UTTAC. 35Cl4- ions extracted
from the sputtering ion source were charge-exchanged
and accelerated up to 4 MeV and used as a probe beam
after shaped as 1×1 mm2 by a double slit system. The
recoils were detected at the angle of 30 degree withrespect to the beam direction. Temperature dependencesof both electric resistivity and Hall conductivity were
measured by van der Pauw method.

Fig. 1. (a) and (b): RHEED images, (c): lattice
constants, (d): ERDA/RBS spectra, and (e): depth
profile of the elements.

Figures 1(a) and (b) show RHEED images ofMgO(001) substrate and MTON(001) films grown with nitrogen gas without argon gas at 500℃,

38

respectively. The streak pattern from MTON(001) is similar to that from the substrate, implying that the
crystal structure of the film is a rock-salt, rather than spinel, type. This is consistent with the XRD results
since observed Bragg points of the film grown with pure nitrogen gas also indicates a rock-salt structure.
On the other hand, when the film is grown with a mixture gas of argon and nitrogen, some films exhibit aspinel structure. The process (or growth) temperature dependent lattice constants both for in-plane and outof-plane axes determined by XRD are summarized in Fig. 1(c). The lattice constant of out-of-plane axis
decreases with increasing the growth temperature, while that of in-plane seems to be independent of thetemperature. The in-plane lattice constant could be locked to the substrate.
TOF-E telescope ERDA results for the film grown at 500°C are shown in Fig. 1(d) and (e). The depthprofiles shown in Fig. 1(e) which is obtained from Fig. 1 (d) indicate that oxygen and nitrogen coexist in
the film, meaning the obtained film is a mixed anion compound. The composition of the film is estimatedas Mg: 21%, Ti: 53%, O:19%, and N: 6%.
We have prepared more than 10 films under different growth conditions with and without argon gas.
Among them, the films grown at 500 and 600°C without argon gas, i.e., with nitrogen gas only, become
conductive at room temperature. The observed values of electrical resistivity of the films at 500 and 600°C
are 3.7×10-3 Ω cm and 1.1×10-3 Ω cm, respectively. The sample grown at a higher temperature seems tohave lower resistivity. According to Fig. 1(d) and (e), the films sputtered with nitrogen gas only arecomposed of nitrogen and oxygen. Since both the ceramic target and the films grown with argon gas only
are electrically insulating, the mixed-anion state [4] of MTON is a key to understand the emergence ofconductivity.

References[1] Jagadeesh S. Moodera et al., J. Phys. Condens. Matter 19 (2007)165202.
[2] Y. K. Takahashi et al., Appl. Phys. Lett. 96 (2010) 072512.
[3] S. Celotto et al., Eur. Phys. J. B 36 (2003) 271.
[4] Hyun-Suk Kim et al., Sci. Rep. 3 (2013) 1459.

39

5.
BEAM IRRADIATION EFFECT

Vacuum chamber for radiation tolerance test of semiconductor devices
used in space. The built-in mechanism enables ion-beam scanning on
A5 size area.

5.1 Study on microalgae mutagenesis with 15N-resonant nuclear reaction
I. Suzuki, R. Morioka, K. Sasa, S. Ishii, K. Tomita1, Y. Iwata1
Natural products such as oils, polysaccharides, and pigments are now being reinvented as essential to asustainable society. Microalgae are superior to both the edible and inedible plants in synthesizing andaccumulating such natural products in high density and in a short term. Accordingly, microalgae are
attracting attention in a wide industrial field of energetics, dietary, nutrition, cosmetics, and pharmaceuticals.
There is still strong resistance in industry to the improvement through GMO (genetically modified
organisms), even though a breeding program of microalgae is necessary to develop more desirable strains
with high productivity. Random mutagenesis, which is optimized in terms of the dose of mutagen such as
effective heavy ion beams as well as typical UV, X-rays, gamma-rays, and also such chemical agent as ethylmethane sulfonate, is exempt from the regulation of GMO. However, such random mutagenesis requires
time-consuming processes for selecting the target mutants, much less to induce a genetic mutation
expressing the target phenotypic trait in microalgae.
The authors focused on nitrogen atom N which is the main constituent in DNA (deoxyribonucleic acid);
seven nitrogen atoms are in every pair of adenine and thymine (AT pair) and eight nitrogen atoms in every
pair of guanine and cytosine (GC pair). Substituting every nitrogen atom in DNA with a stable nitrogenisotope 15N enriched higher than 98% in abundance, we can obtain DNA labeled with 15N isotope(15N_DNA). Proton irradiation to 15N_DNA induces the 15N(p, α1γ)12C resonant nuclear reaction at resonant
energy of 0.897 MeV, and then deletion of the target 15N nucleus and high-density excitation of molecules
near the target 15N by secondary ions of α (4He2+) and 12C6+ happen inside 15N_DNA. Resultantly, 15Nspecific mutagenesis to DNA is possibly realized since the electronic excitation effect of proton at theresonant energy is much smaller than that of the secondary heavy ions. This new mutagenesis has anadvantage exceeding heavy ion irradiation of the conventional random mutagenesis, where a whole cell is
exposed to high-density excitation. Furthermore, the 4.43 MeV gamma-rays from the 15N-resonant nuclear
reaction possess high penetration power through matter, hence they are detectable from the outside of thevacuum irradiation system. The detection of 4.43 MeV gamma-rays enables to accurately monitor thenumber of 15N-resonant nuclear reaction occurring in 15N_DNA during proton beam irradiation. Carefulanalyses of the relation between mutant strains and 4.43 MeV gamma-ray yields lead to establishing a newart of a simultaneous counting system of genetic mutation.
We performed an examination of the new mutagenesis to an artificial DNA and freeze-dried Escherichia
coli (JM109) [1, 2]. 15N-enriched Oligo DNA of 84 bps (base pairs) containing 15N with abundance higher
than 98% was artificially generated by the PCR (polymerase chain reaction) method. The 15N-labeled Oligo
DNA has a molecular mass of 51,773 Da and contains 549 15N atoms. The proton-irradiated Oligo DNA
specimens were ligated with the plasmid DNA harboring the ampicillin resistance gene. The plasmid DNA
ligated with a non-damaged Oligo DNA specimen forming a ring shape plays a role of the plasmid annular1

National Institute of Advanced Industrial Science and Technology (AIST).

40

vector to Escherichia coli, which can grow to form colonies on the medium with ampicillin. The number ofcolonies of JM109 grown in the agar medium containing the plasmid DNA ligated with 15N-labeled Oligo
DNA were obviously reduced. The result indicated that the 15N-labeled Oligo DNA was ruptured by proton
beam irradiation and failed to form a plasmid annular vector in JM109 comparing to the non-irradiation
conditions.
Freeze-dried cells of Escherichia coli (JM109) were possibly alive in the vacuum system for proton
beam irradiation. 15N-labeled JM109 cells grown in the agar medium fed with 15NH4+ ions contain 15N inevery cell organ such as the protein, the nucleic acid, and the cortex. Glutamine synthetase inhibitor of MSX(methionine sulfoximine) plays a role to stop the 15N flow to the system synthesizing the protein and thecortex through the glutamyl cycle. We obtained Escherichia coli (JM109) strains that have the specificnucleic acid labeled with 15N.
Proton beam irradiation was carried atenergies from 0.884 MeV to 0.906 MeV aroundthe center of the resonant energy of 0.897 MeV
Yield from the 4.43
MeV gamma-rays

using both the 1 MV Tandetron at UTTAC and 4
MV Van de Graaff accelerator at AIST. Typicalbeam current was 1 nA for irradiation to theartificial DNA and 0.1 nA for microalgae. 4.43
MeV gamma-ray yields were detected with a
BGO (Bi4Ge3O12) detector. Figure 1 shows
measured gamma-ray spectra, where the natural
background is so low as to detect the signals
from the 4.43 MeV gamma-rays with highFig. 1. Gamma ray spectra emitted from 15N(1H, α1γ)12C
efficiency.
resonant nuclear reaction. 40K and 208Tl indicate the natural
The authors will clarify in future works the 1.4608 MeV and 2.6145 MeV peaks, respectively.
validity of the new mutagenesis with the 15N-

resonant nuclear reaction: the effects of deletion of the target 15N nucleus and high-density excitation ofmolecules near the target 15N, and the art of introduction of 15N inside the target genes or the nearest position
to them.
References[1] Y. Iwata et al., European Advanced Materials Congress (EAMC2019), Stockholm, August 11 – 14, 2019.
[2] R. Morioka et al., The 2019 International Postgraduate Academic Forum, China University ofGeosciences, Beijing, September 20 – 23, 2019.

41

6.
LIST OF PUBLICATIONS AND PRESENTATIONS

Research reports published on the UTTAC web since 2016 when the 6MV
tandem accelerator started regular operation after 2 years of construction.

6.1

Journals

ACCELERATOR AND RELATED FACILITIES
1. H. Nakamura, H. Matsumura, G. Yoshida, A. Toyoda, K. Masumoto, T. Miura, K. Sasa, andT. Moriguchi, “Investigation of neutron-fluence measurement methods for estimating neutron-induced
activity from an electrostatic accelerator source”, Environmental Radiochemical Analysis VI, Royal
Society of Chemistry (2019) 152.

NUCLEAR AND ATOMIC PHYSICS
1. M. Tanaka, M. Takechi, A. Homma, M. Fukuda, D. Nishimura, T. Suzuki, Y. Tanaka, T. Moriguchi,
D.S. Ahn, A. Aimaganbetov, M. Amano, H. Arakawa, S. Bagchi, K.-H. Behr, N. Burtebayev,
K. Chikaato, H. Du, S. Ebata, T. Fujii, N. Fukuda, H. Geissel, T. Hori, W. Horiuchi, S. Hoshino,
R. Igosawa, A. Ikeda, N. Inabe, K. Inomata, K. Itahashi, T. Izumikawa, D. Kamioka, N. Kanda, I. Kato,
I. Kenzhina, Z. Korkulu, Y. Kuk, K. Kusaka, K. Matsuta, M. Mihara, E. Miyata, D. Nagae, S. Nakamura,
M. Nassurlla, K. Nishimuro, K. Nishizuka, K. Ohnishi, M. Ohtake, T. Ohtsubo, S. Omika, H. J. Ong,
A. Ozawa, A. Prochazka, H. Sakurai, C. Scheidenberger, Y. Shimizu, T. Sugihara, T. Sumikama,
H. Suzuki, S. Suzuki, H. Takeda, Y.K. Tanaka, I. Tanihata, T. Wada, K. Wakayama, S. Yagi,
T. Yamaguchi, R. Yanagihara, Y. Yanagisawa, K. Yoshida, and T.K. Zholdybayev, “Swelling of doubly
magic 48Ca core in Ca isotopes beyond N = 28”, Phys. Rev. Lett. 124 (2020) 102501.
2. T. Moriguchi, M. Amano, A. Ozawa, W. Horiuchi, Y. Abe, T. Fujii, R. Kagesawa, D. Kamioka,
A. Kitagawa, M. Mukai, D. Nagae, M. Sakaue, S. Sato, S. Suzuki, T. Suzuki, T. Yamaguchi, andK. Yokota, “Energy dependence of total reaction cross sections for 17Ne on a proton target”, Nucl. Phys.
A 994 (2020) 121663.
3. S. Omika, T. Yamaguchi, N. Tadano, Y. Abe, M. Amano, Z. Ge, D. Kamioka, T. Moriguchi, D. Nagae,
S. Naimi, A. Ozawa, F. Suzaki, S. Suzuki, T. Suzuki, T. Uesaka, M. Wakasugi, K. Wakayama, andY. Yamaguchi, “Development of a new in-ring beam monitor in the Rare-RI Ring”, Nucl. Instrum.
Methods B 463 (2020) 241.
4. Z. Ge, T. Uesaka, S. Naimi, D. Nagae, Y. Abe, S. Omika, F. Suzaki, T. Yamaguchi, Y. Yamaguchi,
M. Wakusugi, H. Li, K. Wakayama, H. Arakawa, K. Inomata, K. Nishimuro, T. Kobayashi, A. Ozawa,
S. Hosoi, Y. Inada, S. Suzuki, T. Moriguchi, M. Mukai, M. Amano, D. Kamioka, and Y. Yano, “Schemeof high-resolution identification and selection of secondary ions for mass measurements with the RareRI Ring”, Hyperfine Interact. 92 (2019) 240.

42

5. M. Machida, D. Nishimura, M. Fukuda, S. Yagi, T. Sugihara, S. Kanbe, S. Yamaoka, M. Takechi,
M. Tanaka, M. Amano, J. Chiba, K. Chikaato, H. Du, S. Fukuda, A. Homma, T. Hori, A. Ikeda, R. Ishii,
T. Izumikawa, Y. Kamisho, N. Kanda, R. Kehl, A. Kitagawa, K. Matsuta, M. Mihara, E. Miyata,
A. Mizukami, T. Moriguchi, M. Nagashima, S. Nakamura, M. Nassurlla, K. Ohnishi, T. Ohtsubo,
S. Sato, J. Shimaya, T. Suzuki, S. Suzuki, T. Tahara, Y. Tanaka, T. Yamaguchi, and R. Yanagihara,“Development of prototype RICH detector with multi-anode photomultipliers for radioactive ions”,
Nucl. Instrum. Methods A 931 (2019) 23.
6. X. Xu, J.H. Liu, C.X. Yuan, Y.M. Xing, M. Wang, Y.H. Zhang, X.H. Zhou, Yu.A. Litvinov, K. Blaum,
R.J. Chen, X.C. Chen, C.Y. Fu, B.S. Gao, J.J. He, S. Kubono, Y.H. Lam, H.F. Li, M.L. Liu, X.W. Ma,
P. Shuai, M. Si, M.Z. Sun, X.L. Tu, Q. Wang, H.S. Xu, X.L. Yan, J.C. Yang, Y.J. Yuan, Q. Zeng,
P. Zhang, X. Zhou, W.L. Zhan, S. Litvinov, G. Audi, S. Naimi, T. Uesaka, Y. Yamaguchi,
T. Yamaguchi, A. Ozawa, B.H. Sun, K. Kaneko, Y. Sun, and F.R. Xu, “Masses of ground and isomericstates of 101In and configuration-dependent shell evolution in odd-A indium isotopes”,
Phys. Rev. C 100 (2019) 051303.
7.

F.C. Ozturk, B. Akkus, D. Atanasov, H. Beyer, F. Bosch, D. Boutin, C. Brandau, P. Bühler, R.B. Cakirli,
R.J. Chen, W.D. Chen, X.C. Chen, I. Dillmann, C. Dimopoulou, W. Enders, H.G. Essel, T. Faestermann,
O. Forstner, B.S. Gao, H. Geissel, R. Gernhäuser, R.E. Grisenti, A. Gumberidze, S. Hagmann,
T. Heftrich, M. Heil, M.O. Herdrich, P.-M. Hillenbrand, T. Izumikawa, P. Kienle, C. Klaushofer,
C. Kleffner, C. Kozhuharov, R.K. Knöbel, O. Kovalenko, S. Kreim, T. Kühl, C. Lederer-Woods,
M. Lestinsky, S.A. Litvinov, Yu.A .Litvinov, Z. Liu, X.W. Ma, L. Maier, B. Mei, H. Miura, I. Mukha,
A. Najafi, D. Nagae, T. Nishimura, C. Nociforo, F. Nolden, T. Ohtsubo, Y. Oktem, S. Omika, A. Ozawa,
N. Petridis, J. Piotrowski, R. Reifarth, J. Rossbach, R. Sánchez, M.S. Sanjari, C. Scheidenberger,
R.S. Sidhu, H. Simon, U. Spillmann, M. Steck, Th. Stöhlker, B.H. Sun, L.A. Susam, F. Suzaki,
T. Suzuki, S.Yu. Torilov, C. Trageser, M. Trassinelli, S. Trotsenko, P.M. Walker, M. Wang, G. Weber,
H. Weick, N. Winckler, X.L. Tu, D.F.A. Winters, P.J. Woods, T. Yamaguchi, X.D. Xu, X.L. Yan,
J.C. Yang, Y.J. Yuan, Y.H. Zhang, X.H. Zhou, and the FRS-ESR, ILIMA, SPARC, and TBWD
Collaborations, “New test of modulated electron capture decay of hydrogen-like 142Pm ions: Precision
measurement of purely exponential decay”, Phys. Lett. B 797 (2019) 134800.

8.

X. Xu, M. Wang, K. Blaum, J.D. Holt, Yu.A. Litvinov, A. Schwenk, J. Simonis, S.R. Stroberg,
Y.H. Zhang, H.S. Xu, P. Shuai, X.L. Tu, X.H. Zhou, F.R. Xu, G. Audi, R.J. Chen, X.C. Chen,
C.Y. Fu, Z. Ge, W.J. Huang, S. Litvinov, D.W. Liu, Y.H. Lam, X.W. Ma, R.S. Mao, A. Ozawa,
B.H. Sun, Y. Sun, T. Uesaka, G.Q. Xiao, Y.M. Xing, T. Yamaguchi, Y. Yamaguchi, X.L. Yan, Q. Zeng,
H.W. Zhao, T.C. Zhao, W. Zhang, and W.L. Zhan, “Masses of neutron-rich 52-54Sc and 54,56Ti nuclides:
The N = 32 subshell closure in scandium”, Phys. Rev. C 99 (2019) 064303.

43

9.

J.T. Zhang, K. Yue, H.X. Li, X.L. Tu, C.J. Shao, P. Ma, B. Mei, X.C. Chen, Y.Y. Yang, X.Q. Liu,
Y.M. Xing K.H. Fang, Z.Y. Sun, M. Wang, Yu.A. Litvinov, T. Yamaguchi, P. Egelhof, Y.H. Zhang, and
X.H. Zhou, “The development of in-ring reaction measurements at the HIRFL-CSR”, Nucl. Instrum.
Methods A 948 (2019) 162848.

10. S. Suzuki, A. Ozawa, D. Kamioka, Y. Abe, M. Amano, H. Arakawa, Z. Ge, K. Hiraishi, Y. Ichikawa,
K. Inomata, A. Kitagawa, T. Kobayashi, H.Fu Li, T. Matsumoto, T. Moriguchi, M. Mukai, D. Nagae,
S. Naimi, S. Omika, S. Sato, Y. Tajiri, K. Wakayama, and T. Yamaguchi, “Efficiency and timing
performance of time-of-flight detector utilizing thin foils and crossed static electric and magnetic fields
for mass measurements with Rare-RI Ring facility”, Nucl. Instrum. Methods A 965 (2020) 163807.

ACCELERATOR MASS SPECTROMETRY
1. M. Matsumura, K. Sasa, T. Matsunaka, K. Sueki, T. Takahashi, and H. Matsuzaki, “Assessing theeffect of laboratory environment on sample contamination for I-129 accelerator mass spectrometry”,
Anal. Sci. 36 (2020) 631.
2. T. Matsunaka, K. Sasa, T. Takahashi, M. Matsumura, K. Sueki, and H. Matsuzaki, “Pre- and postaccident 14C activities in tree rings near the Fukushima Dai-ichi Nuclear Power Plant”,
Radiocarbon 61 (2019) 1633.
3. J. Chen, H. Shen, K. Sasa, H. Lan, T. Matsunaka, M. Matsumura, T. Takahashi, S. Hosoya, M. He,
Y. He, Z. Li, Z. Zhao, Z. Zhao, M. Liu, S. Wei, M. Qi, Q. Zhao, X. Qin, X. Chen, and S. Jiang,“Radio carbon dating of Chinese ancient tea trees”, Radiocarbon 61 (2019) 1741.
4. H. Shen, K. Sasa, Q. Meng, M. Matsumura, T. Matsunaka, S. Hosoya, T. Takahashi, M. Honda,
K. Sueki, M. He, B. Huang, Q. Zhao, K. Dong, Y. Guan, X. Ruan, and S. Jiang, “Exposure age
dating of Chinese tiankengs by 36Cl-AMS”, Nucl. Instrum. Methods B 459 (2019) 29.
5. H. Shen, K. Sasa, Q. Meng, M. Matsumura, T. Matsunaka, S. Hosoya, T. Takahashi, M, Honda,
K. Sueki, L. Chen, H. Lu, M. He, B. Huang, Y. Qin, Z. Li, H. Lan, Z. Li, Z. Zhao, N. Liu, S. Wei,
M. Qi, Q. Zhao, K. Dong, Y. Guan, and S. Jiang, “36Cl preparation method for Chinese karst
samples (Tiankeng)”, Nucl. Instrum. Methods B 458 (2019) 126.

44

BEAM AND ISOTOPE APPLICATIONS
1. A. Yamazaki, H. Naramoto, K. Sasa, S. Ishii, S. Tomita, M. Sataka, H. Kudo, M. Ohkubo, andA. Uedono, “Two-dimensional mapping of hydrogen and other elements in materials withmicrobeam-based transmission ERDA and PIXE”, Nucl. Instrum. Methods B 450 (2019) 319.
2. Y. Yamashita, Y. Takahara, T. Sato, K. Toko, A. Uedono, and T. Suemasu, “Simple way of finding Ba
to Si deposition rate ratios for high photoresponsivity in BaSi2 films by Raman spectroscopy”,
Appl. Phys. Express 12 (2019) 055506.
3. H.J. Zhang, S. Sellaiyan, K. Sako, A. Uedono, Y. Taniguchi, and K. Hayashi, “Effect of free-volume
holes on static mechanical properties of epoxy resins studied by positron annihilation and PVT
experiments”, Polymer 190 (2020) 122225.
4. M. Shimizu, R. Álvarez-Asencio, N. Nordgren, and A. Uedono, “Preparation and characterization ofcellulose acetate membranes with TEMPO-oxidized cellulose nanofibrils containing alkyl
ammonium carboxylates”, Cellulose 27 (2019) 1357.
5. S. Sellaiyan, A. Uedono, L.V. Devi, and K. Sivaji, “Er3+ induced point defects in ZnO and impact of
Li+/Na+/K+ on the vacancy defects in ZnO:Er studied by positron annihilation spectroscopy”,
Appl. Phys. A 125 (2019) 498.
6. H. Iguchi, T. Narita, K. Kataoka, M. Kanechika, and A. Uedono, “Impact of defects on the electricalproperties of p-n diodes formed by implanting Mg and H ions into N-polar GaN”,
J. Appl. Phys. 126 (2019) 125102.
7. S. Ishibashi, A. Uedono, H. Kino, T. Miyake, and K. Terakura, “Computational study of positronannihilation parameters for cation mono-vacancies and vacancy complexes in nitride semiconductor
alloys”, J. Phys.: Condens. Matt. 47 (2019) 475401.
8. A. Uedono, H. Iguchi, T. Narita, K. Kataoka, W. Egger, T. Koschine, C. Hugenschmidt,
M. Dickmann, K. Shima, K. Kojima, S.F. Chichibu, and S. Ishibashi, “Annealing behavior of
vacancy‐type defects in Mg- and H-implanted GaN studied using monoenergetic positron beams”,
Phys. Status Solidi B 256 (2019) 1900104.
9. 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 thenear-band-edge emission of epitaxial and ion-implanted GaN on GaN structures”,
Jpn. J. Appl. Phys. 58 (2019) SC0802.

45

10. A. Uedono, A.-M. Siladie, J. Pernot, B. Daudin, and S. Ishibashi, “Vacancy-type defects in GaN selfassembled nanowires probed using monoenergetic positron beam”,
J. Appl. Phys. 125 (2019) 175705.
11. A. Uedono, K. Sako, W. Ueno, and M. Kimura, “Free volumes introduced by fractures of CFRP
probed using positron annihilation”, Composites Part A 122 (2019) 54.
12. 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. Crys. Growth 511 (2019) 15.
13. S. Sellaiyan, L. Vimala Devi, K. Sako, A. Uedono, and K. Sivaji, “Effect of dopant concentration
and annealing of Yttrium doped CuO nanocrystallites studied by positron annihilation
spectroscopy”, J. Alloy. Compd. 788 (2019) 549.
14. 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.
15. Y. Yamashita, Y. Takahara, T. Sato, K. Toko, A. Uedono, and T. Suemasu, “Simple way of finding Ba
to Si deposition rate ratios for high photoresponsivity in BaSi2 films by Raman spectroscopy”,
Appl. Phys. Express 12 (2019) 05506.
16. A. Uedono, W. Egger, C. Hugenschmidt, and S. Ishibashi, “Effect of illumination on positron statesin wide bandgap semiconductors”, 18th Int. Conf. Positron Annihilation (ICPA-18),
AIP Conf. Proc. 2182 (2019) 050006.
17. A. Yamazaki, K. Sasa, S. Tomita, S. Ishii, H. Naramoto, M. Sataka, H. Kudo, G. Itoh, and M.
Ohkubo, “Microscopic 3-dimensional mapping of hydrogen bubbles in polycrystalline Al by elastic
recoil detection analysis under transmission geometry”, AIP Advances 9 (2019) 105111.
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”, Nucl. Instrum. Methods B 460 (2019) 30.
19. S. Goto, H. Kura, H. Yanagihara, E. Kita, M. Tsujikawa, R. Sasaki, M. Shirai, Y. Kobayashi,
T. Honda, and K. Ono, “Positive Weiss temperature in layered antiferromagnetic FeNiN for highperformance permanent magnets”, ACS Appl. Nano Mater. 2 (2019) 6909.

4620. H. Latiff, M. Kishimoto, J. Inoue, E. Kita, H. Yanagihara, and T. Devillers, “Strain-induced

magnetic anisotropy via the Jahn-Teller effect and the magnetoelastic coupling of tetragonally
distorted (Cu,Co)Fe2O4 particles”, J. Magn. Magn. Mater. 489 (2019) 165380.
21. 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 Sci. 3 (2019) 8.

22. S. Fujiwara, Y. Kurauchi, Y. Hirose, I. Harayama, D. Sekiba, T. Hasegawa, “Modification ofelectrical and magnetic properties of Fe3O4 epitaxial thin films by nitrogen substitution for oxygen”,
ACS Applied Electronic Materials 1 (2019) 595.
23. D. Kutsuzawa, Y. Hirose, Y. Sugisawa, J. Kikuda, D. Sekiba, and T. Hasegawa, “Enhanced
ferromagnetic transition temperature in NdOxDy epitaxial thin films”,
Phys. Rev. Mater. 3 (2019) 044408.
24. R. Kitahara, K. Hirota, S. Ieki, T. Ino, Y. Iwashita, M. Kitaguchi, J. Koga, K. Mishima, A. Morishita,
N. Nagakura, H. Oide, H. Otono, Y. Seki, D. Sekiba, T. Shima, H. M. Shimizu, N. Sumi, H. Sumino,
K. Taketani, T. Tomita, T. Yamada, S. Yamashita, M. Yokohashi, and T. Yoshioka, “Improved
accuracy in the determination of the thermal cross section of 14N(n, p)14C for neutron lifetime
measurement”, Prog. Theor. Exp. Phys. 093C01 (2019).
25. I. Harayama, T. Tamura, S. Ishii, K. Ozeki, and D. Sekiba, “Improvement of detection limit forhydrogen in high-resolution ERDA by using scanning solid state detector”,
Nucl. Instrum. Methods B 456 (2019) 74.
26. D.J. Juntila, K. Yoneda, and I. Suzuki, “Genetic modification of the thraustochytrid
Aurantiochytrium sp. 18W-13a for cellobiose utilization by secretory expression of β-glucosidasefrom Aspergillus aculeatus”, Algal Res. 40 (2019) 101503.
27. C. Degraeve-Guilbault C., R.E. Gomez, C. Lemoigne, N. Pankasem, S. Morin, K. Tuphile, J. Joubes,
J. Jouhet, J. Gronnier, I. Suzuki, D. Frédéric, and F. Corellow, “Plastidic Δ6 fatty-acid desaturases
with distinctive substrate specificity regulate the pool of c18-pufas in the ancestral picoalga
Ostreococcus tauri” bioRχiv, doi: https://doi.org/10.1101/2020.03.10.986216 (2020)

6.2

Reviews and books

1.

T. Matsunaka and K. Sasa, Chapter 6.4, “Distribution and migration of radioiodine in terrestrial
environment”, Environmental Contamination from the Fukushima Nuclear Disaster, Cambridge

47

University Press, pp186-190, 2019-08-15. ISBN: 9781108475808.

6.3

Poster and oral presentations at academic meetings

1.

A. Uedono, W. Egger, C. Hugenschmidt, and S. Ishibashi, “Control of vacancy-type defects in Mg
implanted GaN studied by positron annihilation spectroscopy”, SPIE Photonics West, OPTO, San
Francisco, USA (Feb. 4, 2020). (Invited talk)2.

S.F. Chichibu, K. Shima, K. Kojima, S. Ishibashi, and A. Uedono, “Origin and dynamic propertiesof major intrinsic nonradiative recombination centers in wide bandgap nitride semiconductors”,
SPIE Photonics West, OPTO, San Francisco, USA (Feb. 4, 2020). (Invited talk)3.

A. Uedono, W. Egger, T. Koschine, C. Hugenschmidt, M. Dickmann, M. Sumiya, and S. Ishibashi,“Open spaces in Al2O3 film deposited on widegap semiconductors probed by monoenergetic
positron beams”, American Vacuum Society Int. Sym. Ohio, USA (Oct. 23, 2019). (Invited talk)4.

A. Uedono, W. Egger, T. Koschine, C. Hugenschmidt, M. Dickmann, and S. Ishibashi, “Annealing
behaviors of open spaces in thin Al2O3 films deposited on semiconductors studied using
monoenergetic positron beams”, 15th Int. Workshop Slow Positron Beam Techniques andApplications, Prague, Czech Republic (Sept. 3, 2019). (Invited talk)5.

S.F. Chichibu, K. Shima, K. Kojima, S. Ishibashi, and A. Uedono, “Impact of Vacancy Complexeson the Nonradiative Recombination Processes in III-N Devices”, 13th Int. Conf. Nitride
Semiconductors, Bellevue, USA (Jul. 10, 2019). (Invited talk)6.

A. Uedono, W. Egger, C. Hugenschmidt, and S. Ishibashi, “Vacancy-type defects in GaN-based
power device structure - defect characterization in ion implanted GaN and Al2O3/GaN -“,Compound Semiconductor Week 2019, Nagoya, Japan (May 22, 2019). (Invited talk)7.

T. Yamaguchi, “ILIMA status report and phase-0 program”, Nuster Week 2019, CNRS, Gif-surYvette, France (Sept. 23−27, 2019). (Invited talk)8.

Y. Shiina, R. Kinoshita, S. Funada, S. Tomita, M. Matsuda, M. Imai, K. Kawatsura, M. Sataka, and
K. Sasa, “Cluster effect on the yield of Auger electrons emitted through Coster–Kronig transitions”,
ISIAC, XXXIst International Conference on Photonic, Electronic, and Atomic Collisions,
Deauville, France (Jul. 23−30, 2019). (Invited Talk)

9.

H. Matsumura, G. Yoshida, A. Toyoda, K. Masumoto, K. Nishikawa, H. Nakamura, T. Miura,48

K. Bessho, K. Sasa, T. Moriguchi, F. Nobuhara, and Y. Nagashima, “Nondestructive high-sensitivity
measurement method for activation estimation in accelerator room concrete”, The 10th International
Symposium on Radiation Safety and Detection Technology (ISORD-10), Taiyuan, China (Jul. 1619, 2019). (Invited Talk)
10. 笹 公和, ”イオンビーム分析法を用いた材料中の水素を含む多元素同時イメージング”, 軽金属学会 アルミニウム中の水素と材料物性研究部会第 2 回研究会, 日本アルミニウム協会東京事務所, 東京 (2019 年 11 月 6 日). (招待講演)
11. 鈴木石根, ”光合成の環境適応からカーボンリサイクル”, 第 138 回バイオ e-カフェ, 筑波大学, つくば (2019 年 11 月 12 日). (招待講演)
12. 岩田康嗣, ”加速器を利用した Protist 遺伝子変異”, 第 58 回つくば藻類プロティストフォー
ラム, 筑波大学, つくば(2019 年 10 月 7 日). (招待講演)
13. Y. Iwata, R. Morioka, I. Suzuki, K. Tomita, N. Orita, T. Matsumoto, A. Masuda, and K. Sasa,”Mutagenesis to the target genes of microalgae with the 15N-resonant nuclear reaction”, 27th
European Advanced Materials Congress, Stockholm, Sweden (Aug. 11−14, 2019). (Invited talk)
14. A. Uedono, “Current trends of electronics and a study of defects in materials for semiconductor
devices”, Martin Luther University, Halle, Germany (Nov. 7-8, Jun. 19−20, 2019).
15. A. Uedono, W. Egger, T. Koschine, C. Hugenschmidt, M. Dickmann, and S. Ishibashi, “Vacancytype defects in ion-implanted GaN probed by monoenergetic positron beams”, MLZ User Meeting
2019, Munich, Germany (Dec. 10, 2019).
16. C. Vallee, M. Bonvalot, B. Pelissier, J.-H. Tortai, S. David, S. Belahcen, V. Pesce, M. Jaffal,
A. Bsiesy, R. Gassilloud, N. Posseme, T. Grehl, P. Bruner, and A. Uedono, “In line and ex situ
metrology and characterization to enable area selective deposition”, American Vacuum Society Int.
Sym., Columbus, USA (Oct. 22, 2019).
17. K. Shima, H. Iguchi, T. Narita, K. Kataoka, K. Kojima, A. Uedono, and S.F. Chichibu,“Photoluminescence studies of sequentially Mg and H ion-implanted GaN with various
implantation depths and crystallographic planes”, 13th Int. Conf. Nitride Semiconductors, Bellevue,
USA (Jul. 10, 2019).
18. M. Zhao, V. Spampinato, A. Franquet, D. Hein, L. Chang, and A. Uedono, “The influence of AlN
nucleation layer on radio frequency (RF) Transmission Loss of GaN-on-Si Structure”, 13th Int.
Conf. Nitride Semiconductors, Bellevue, USA (Jul. 9, 2019).

4919. S. Takashima, R. Tanaka, K. Ueno, H. Matsuyama, Y. Fukushima, M. Edo, K. Shima, K. Kojima,
S.F. Chichibu, and A. Uedono, “Evaluation of subsequent implantation effect into Mg implanted
region in GaN”, 13th Int. Conf. Nitride Semiconductors, Bellevue, USA (Jul. 8, 2019).
20. 秩父重英, 嶋 紘平, 小島一信, Moody Baxter, 三田清二, Collazo Ramon, Sitar Zlatko,
熊谷義直, 上殿明良, “PVT 成長 AlN 上に HVPE 成長させた Si 添加 AlN 基板の陰極線蛍光評価”, 第 67 回応用物理学会春季学術講演会, 上智大学, 東京 (2020 年 3 月 12−15 日).
21. 嶋 紘平, 中須大蔵, 正直花奈子, 上杉謙次郎, 小島一信, 上殿明良, 三宅秀人, 秩父重英,“高温アニールしたスパッタ AlN 上に成長させた AlN の陰極線蛍光評価(1)”, 第 67 回応用物理学会春季学術講演会, 上智大学, 東京 (2020 年 3 月 12−15 日).
22. 中須大蔵, 嶋 紘平, 正直花奈子, 上杉謙次郎, 小島一信, 上殿明良, 三宅秀人, 秩父重英,“高温アニールしたスパッタ AlN 上に成長させた AlN の陰極線蛍光評価(2)”, 第 67 回応用物理学会春季学術講演会, 上智大学, 東京 (2020 年 3 月 12−15 日).
23. 上殿明良, 上野 航, 細井卓治, W. Egger, T. Koschine, C. Hugenschmidt, M. Dickmann,
渡部平司, “陽電子消滅による SiO2/GaN 構造の空隙と空孔型欠陥の検出”, 第 67 回応用物理学会春季学術講演会, 上智大学, 東京 (2020 年 3 月 12−15 日).
24. 角谷正友, 高原悠希, 矢代秀平, 本田 徹, Dickerson Kindole, 竹端寛治, 今中康貴,
上殿明良, “InGaN/GaN ヘテロ構造成長における AlN テンプレートの変化”, 第 67 回応用物
理学会春季学術講演会, 上智大学, 東京 (2020 年 3 月 12−15 日).
25. 秩父重英, 小島一信, 羽豆耕治, 石川陽一, 古澤健太郎, 三田清二, Collazo Ramon,
Sitar Zlatko, 上殿明良, “気相成長 m 面自立 AlN 基板およびホモエピタキシャル層の偏光特性と発光ダイナミクス”, 第 80 回応用物理学会秋季学術講演会, 北海道大学, 札幌 (2019年 9 月 19 日).
26. N. Nitta, Y. Murao, H. Tsuchida, S. Tomita, K. Sasa, K. Hirata, H. Shibata Y. Hirano K. Yamada,A. Chiba, Y. Saitoh, K. Narumi, and Y. Hoshino, “Surface structures on Ge and Si irradiated with
C60 cluster ion beams”, 23rd International Workshop on Inelastic Ion-Surface Collisions (IISC-23),
Matsue, Japan (Nov.17−22, 2019).
27. 景澤怜央 他, ”固体水素標的を用いた 17F の反応断面積測定”, 日本物理学会第 75 回年次大会、名古屋大学, 名古屋 (2020 年 3 月 16−19 日).

50

28. T. Moriguchi et al., “Energy dependence of reaction cross section for 17Ne on proton target”, The
International Nuclear Physics Conference (INPC) 2019, Scottish Event Campus, Glasgow, UK(Jul. 29−Aug. 2, 2019).
29. A. Ozawa et al., “Mass measurements for Ni-isotopes in Rare-RI Ring RIBF”, China-Japan
Collaboration Workshop on “Nuclear Mass and Life for Unraveling Mysteries of R-process”,
ITP/CAS, Beijing, China (Oct. 9−12, 2019).
30. 向井もも 他, ”薄膜を利用した飛行時間検出器の開発”, 日本物理学会 2019 年秋季大会, 山形大学, 山形 (2019 年 9 月 17- 20 日).
31. M. Mukai et al., “Measurement of nuclear magnetic dipole moments of 196-198Ir from laser
spectroscopy at KISS”, INPC2019, Glasgow, UK (Jul. 28−Aug. 2 2019).
32. T. Yamaguchi et al., “New experimental plan and detector R&D at the Rare-RI Ring facility”,
China-Japan Collaboration Workshop on “Nuclear Mass and Life for Unraveling Mysteries of Rprocess”, ITP/CAS, Beijing, China (Oct. 9−12, 2019).
33. K. Sasa, M. Matsumura, T. Matsunaka, T. Takahashi, Y. Satou, N. Kinoshita, H. Matsuzaki, andK. Sueki, “Distribution of 129I in the terrestrial environment around the Fukushima Daiichi Nuclear
Power Plant before and after the accident”, 5th International Conference on Environmental
Radioactivity, Prague, Czech Republic (Sept. 8−13, 2019).
34. Y. Ochiai, K. Sasa, Y. Tosaki, T. Takahashi, M. Matsumura, and K. Sueki, “Variation of Chlorine-36
deposition flux in precipitation at Tsukuba, Japan”, 5th International Conference on Environmental
Radioactivity, Prague, Czech Republic (Sept. 8−13, 2019).
35. K. Sasa, T. Takahashi, M. Matsumura, Y. Ochiai, T. Matsunaka, A. Sakaguchi, H. Shen, andK. Sueki, “Progress of ultrasensitive detection techniques for the 6 MV multi-nuclide AMS systemat the University of Tsukuba”, The 8th East Asia Accelerator Mass Spectrometry Symposium (EAAMS 8), Nagoya University, Nagoya, Japan (Dec. 3−6, 2019).
36. K. Kanzawa, F. Miyake, Y. Tada, K. Horiuchi, K. Ohtani, K. Sasa, Y. Motizuki, K. Takahashi,
Y. Nakai, H. Motoyama, and H. Matsuzaki, “Variation of cosmogenic 10Be for cosmic ray event in~5480 BC from Antarctic Dome Fuji ice core”, The 8th East Asia Accelerator Mass Spectrometry
Symposium (EA-AMS 8), Nagoya University, Nagoya, Japan (Dec. 3−6, 2019).

51

37. Y. Ochiai, K. Sasa, Y. Tosaki, T. Takahashi, M. Matsumura, and K. Sueki, “Variations of Beryllium10 and Chroline-36 deposition flux at Tsukuba, Japan”, The 8th East Asia Accelerator Mass
Spectrometry Symposium (EA-AMS 8), Nagoya University, Nagoya, Japan (Dec. 3−6, 2019).
38. 笹 公和, 石井 聡, 高橋 努, 大和良広, 田島義一, 松村万寿美, 森口哲朗, 上殿明良, “筑波大学タンデム加速器施設 UTTAC の現状(2018 年度)”, 第 32 回タンデム加速器及びその周辺技術の研究会, 神戸大学, 神戸 (2019 年 7 月 5−6 日).
39. 笹 公和, 石井 聡, 高橋 努, 大和良広, 田島義一, 松村万寿美, 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 16 回日本加速器学会年会, 京都大学, 京都(2019 年 7 月 31 日 − 8 月 3 日).
40. 笹 公和, 落合悠太, 高橋 努, 松村万寿美, 末木啓介, ”カルシウム 41 の加速器質量分析法
による高感度検出手法の開発”, 2019 年第 80 回応用物理学会秋季学術講演会, 北海道大学,
札幌 (2019 年 9 月 18−21 日).
41. 菅澤佳世, 三宅芙沙, 堀内一穂, 笹 公和, 望月優子, 高橋和也, 中井陽一, 本山秀明,
松崎浩之, ”ドームふじアイスコア中 10Be と 36Cl 濃度の測定による BC5480 年宇宙線イベン
トの調査”, 山形大学, 山形 (2019 年 9 月 17−20 日).
42. 落合悠太, 笹 公和, 高橋 努, 松村万寿美, 末木啓介, ”加速器質量分析法を用いた塩素 36
測定における低バックグラウンド検出手法の開発”, 2019 年第 80 回応用物理学会秋季学術講演会, 北海道大学, 札幌 (2019 年 9 月 18−21 日).
43. 横山大輝, 笹 公和, 松中哲也, 高橋 努, 松村万寿美, 高野健太, 落合悠太, 長谷川 涼,
太田裕貴, 末木啓介, ”福島県の避難指示区域における I-129 の分布と Cs-137 との関係性”,
日本放射化学会第 63 回討論会(2019), いわき産業創造館, いわき (2019 年 9 月 24−26 日).
44. 松中哲也, 笹 公和, 高橋 努, 松村万寿美, 末木啓介, 松崎浩之, ”樹木年輪に記録された福島第一原子力発電所発事故由来 C-14 の分布”, 日本放射化学会第 63 回討論会(2019), いわき産業創造館, いわき (2019 年 9 月 24−26 日).
45. 松村万寿美, 森口哲朗, 笹 公和, 上殿明良, ”筑波大学 6MV タンデム加速器ビームラインの放射線サーベイ”, 公益社団法人日本アイソトープ協会 放射線安全取扱部会年次大会,
倉敷市芸文館, 倉敷 (2019 年 10 月 24−25 日).
46. 松中哲也, 後藤章夫, 渡邊隆広, 土屋範芳, 平野伸夫, 笹 公和, ”蔵王山における火山活動と熱水系ヨウ素同位体比の変動”, 日本陸水学会 第 84 回金沢大会, 金沢大学, 金沢 (2019 年

52

9 月 27−30 日)．
47. 菰田誉大, 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 クラスターイオンを照射した Si の照射角度依存性”, QST 高崎サイエンスフェスタ 2019, 高崎シティギャラリー, 高崎( 2019 年 12 月 10−11 日).
48. 菅澤佳世, 三宅芙沙, 多田悠馬, 堀内一穂, 大谷 昴, 笹 公和, 高橋 努, 松村万寿美, 落合悠太, 望月優子, 高橋和也, 中井陽一, 本山秀明, 松崎浩之, ”BC5480 年宇宙線イベントにおける 10Be と 36Cl の変動 :ドームふじアイスコアからの証拠”, 応用物理学会 2020 年春
季学術講演会, 上智大学, 東京 (2020 年 3 月 12−15 日).
49. 笹 公和, 山崎明義, 石井 聰, 冨田成夫, 左高正雄, 楢本 洋, 工藤 博, “構造材料用マイク
ロビーム分析装置を用いた水素を含む多元素同時分析法の開発”, 応用物理学会 2020 年春
季学術講演会, 上智大学, 東京 (2020 年 3 月 12−15 日).
50. S. Tomita, S. Shiki, G. Fujii, and M. Ukibe, “Characteristics of kinetic energy sensitive detection ofkeV particles using superconducting tunnel junction”, 23rd International Workshop on Inelastic IonSurface Collisions, Matsue, Japan (Nov. 17−22, 2019).
51. 冨田成夫, 志岐成友, 藤井 剛, 浮辺雅弘, “超伝導トンネル接合検出器のイオン検出特性”,
応用物理学会秋季学術講演会, 北海道大学, 札幌 (2019 年 9 月 18−21 日).
52. 新家弘也, 副島敬佑, 山下 晃, 岩田康嗣, 長谷純宏, 大野 豊, 鈴木石根, “重イオンビーム
照射変異によるオイル分解抑制藻の解析, QST 高崎サイエンスフェスタ 2019, 高崎シティ
ギャラリー, 高崎 ( 2019 年 12 月 10−11 日).
53. T. Inada and I. Suzuki, “Production of the ω-1 hydroxy fatty acids in Synechocystis sp. PCC 6803”,
12th International Marine Biotechnology Conference, Shimidzu, Japan (Sept. 9−12, 2019).
54. N. Pankasem, R.K. Bakku, S. Machida, F. Corellou, F. Domergue, N. Nomura, and I. Suzuki,“Substrate specificity of the cytochrome b5 -containing Δ6 fatty acid desaturase localized in thechloroplast of the marine prasinophyte, Ostreococcus tauri”, 12th International Marine
Biotechnology Conference, Shimidzu, Japan, (Sept. 9−12, 2019).
55. M. Junaid, A. Otero, and I. Suzuki, “Development of the reversible regulatory system for gene
expression using an acyl-homoserine lactone-mediated sensor and a lactonase in the
cyanobacterium Synechocystis sp. PCC 6803”, 12th International Marine Biotechnology

53

Conference, Shimidzu, Japan (Sept. 9-12, 2019).
56. T. Kashiwagi, K. Hayashi, M. Yoshimura, and I. Suzuki, “Development of a device for efficientdissolution of carbon dioxide into the mass culture of algae”, 12th International Marine
Biotechnology Conference, Shimidzu, Japan (Sept. 9−12, 2019).
57. 岩田康嗣, 鈴木石根, 鈴木裕司, 細田 忍, 西川暢子, “ 15Ｎ共鳴核反応による微細藻標的遺伝子改変とエネルギー生産性利用を目指して”, 第 7 回「機能性バイオ」ミニシンポ, 東京
大学, 東京 (2019 年 7 月 4 日).
58. Y. Sugisawa, D. Sekiba, I. Harayama, “Development of low-energy TOF-E telescope ERDA for
depth profiling of light elements at UTTAC in the University of Tsukuba”, 24th International
Conference on Ion Beam Analysis, Antibes, France (Oct. 13−18, 2019).
59. 杉澤悠紀, 関場大一郎, 廣瀬 靖, 原山 勲, “多層膜中軽元素の深さ分布測定に向けた TOFE telescope ERDA 装置の開発”, 日本物理学会 2019 年秋季大会, 岐阜大学, 岐阜( 2019 年 9 月 10−13 日).
60. 岡部宏紀, 日野正裕, 広田克也, 家城 斉, 猪野 隆, 岩下芳久, 北口雅暁, 北原龍之介,
古賀 淳, 三島賢二, 森下 彩, 中野祐輔, 長倉直樹, 小田達郎, 生出秀行, 音野瑛俊,
関 義親, 関場大一郎, 嶋 達志, 清水裕彦, 角 直幸, 角野浩史, 竹谷 薫, 富田龍彦,
上原英晃, 山田崇人, 山下 了, 横橋麻美, 吉岡瑞樹, “J-PARC/BL05 における中性子寿命測定実験: SFC アップグレード”, 日本物理学会 2019 年秋季大会, 山形大学, 山形(2019 年 9 月 17−20 日).
61. 三島賢二, 広田克也, 家城 斉, 猪野 隆, 岩下芳久, 梶原昇吾, 加藤 悠, 北口雅暁,
北原龍之介, 古賀 淳, 牧瀬 壮, 茂木駿紀, 森下 彩, 長倉直樹, 中野祐輔, 生出秀行,
岡部宏紀, 音野瑛俊, 關 義親, 関場大一郎, 嶋 達志, 清水裕彦, 杉澤悠紀, 角 直幸,
角野浩史, 竹谷 薫, 田辺友彦, 富田龍彦, 上原英晃, 山田崇人, 山下 了, 矢野浩大,
横橋麻美, 吉岡瑞樹, “J-PARC/BL05 における中性子寿命測定実験：3He 数密度導出法の改良”, 日本物理学会 2019 年秋季大会, 山形大学, 山形 (2019 年 9 月 17−20 日).
62. 市川 豪, 広田克也, 家城 斉, 猪野 隆, 岩下芳久, 梶原昇吾, 加藤 悠, 北口雅暁,
北原龍之介, 古賀 淳, 牧瀬 壮, 三島賢二, 茂木駿紀, 森川滉己, 森下 彩, 長倉直樹,
中野祐輔, 生出秀行, 岡部宏紀, 音野瑛俊, 關 義親, 関場大一郎, 嶋 達志, 清水裕彦,
杉澤悠紀, 角 直幸, 角野浩史, 竹谷 薫, 田辺友彦, 富田龍彦, 上原英晃, 山田崇人,
山下 了, 矢野浩大, 横橋麻美, 吉岡瑞樹, “J-PARC/BL05 における中性子寿命測定実験：バックグラウンドと系統誤差の評価”, 日本物理学会第 75 回年次大会、名古屋大学, 名古屋(2020 年 3 月 16−19 日).

5463. 森川滉己, 広田克也, 市川 豪, 家城 斉, 猪野 隆, 岩下芳久, 梶原昇吾, 加藤 悠,
北口雅暁, 北原龍之介, 古賀 淳, 牧瀬 壮, 三島賢二, 茂木駿紀, 森下 彩, 長倉直樹,
中野祐輔, 生出秀行, 岡部宏紀, 音野瑛俊, 關 義親, 関場大一郎, 嶋 達志, 清水裕彦,
杉澤悠紀, 角 直幸, 角野浩史, 竹谷 薫, 田辺友彦, 富田龍彦, 上原英晃, 山田崇人,
山下 了, 矢野浩大, 横橋麻美, 吉岡瑞樹, “J-PARC/BL05 における中性子寿命測定実験：
TPC 動作ガス中の 3He 含有率評価” , 日本物理学会第 75 回年次大会、名古屋大学, 名古屋(2020 年 3 月 16−19 日).
64. 岡部宏紀, 日野正裕, 広田克也, 家城 斉, 猪野 隆, 岩下芳久, 北口雅暁, 北原龍之介,
古賀 淳, 三島賢二, 森下 彩, 中野祐輔, 長倉直樹, 小田達郎, 生出秀行, 音野瑛俊,
関 義親, 関場大一郎, 嶋 達志, 清水裕彦, 角 直幸, 角野浩史, 竹谷 薫, 富田龍彦,
上原英晃, 山田崇人, 山下 了, 横橋麻美, 吉岡瑞樹, “J-PARC/BL05 における中性子寿命測定実験：SFC アップグレード”, 日本物理学会第 75 回年次大会、名古屋大学, 名古屋(2020 年 3 月 16−19 日).
65. 福本通孝, 廣瀬 靖, 杉澤悠紀, 関場大一郎, 長谷川哲也, “パイクロア型 Sn2Ta2O7 エピタキ
シャル薄膜への p 型ドーピング”, 応用物理学会 2020 年春季学術講演会, 上智大学, 東京(2020 年 3 月 12−15 日).

55

6.4

UTTAC seminars

2019.10.21

Neutron skins of Ca isotopes across neutron magic number N=28, Masaomi Tanaka(Research Center for Superheavy Elements, Kyushu University)

2019.10.31

Passivation and Compensation of Mg-doping in GaN and AlGaN, Andrew Klump (North
Carolina State University)

2019.11.8

Introduction of materials science studies by means of the beta-NMR technique, Mototsugu
Mihara (Osaka University)

2019.11.14

Nano-Scale Materials Modification and Materials Analysis, Leonard C. Feldman (Rutgers
University)

2019.11.14

Observation of quantum diffusion of hydrogen in Palladium by electrical measurement,
Takahiro Ozawa (University of Tokyo)

2019.11.14

Proposal of site-selective electronic structure investigation by ion beam, Daiichiro Sekiba(University of Tsukuba)

2019.11.14

High-resolution imaging of soft materials and direct nano-patterning of graphene byhelium ion microscopy, Shinichi Ogawa (National Institute of Advanced Industrial Scienceand Technology [AIST])

2020.1.7

Neutral mesons production in jets in p-Pb collisions at √𝑠= 5.02 TeV in LHC-ALICE

experiment, Masahiro Takamura (University of Tsukuba)
2020.1.7

Elliptic flow of electrons from heavy-flavour hadron decays in Pb-Pb collisions at √𝑠=

5.02 with ALICE at the LHC, Kenichi Tadokoro (University of Tsukuba)
2020.1.7

Fluctuation by unfolding of net-proton distribution in √𝑠= 27 GeV Au+Au collisions

at the RHIC-STAR experiment, Kana Nakagawa (University of Tsukuba)
2020.1.7

Azimuthal anisotropic flow in Au+Au collisions with collider and fixed-target mode at√𝑠 = 7.7 GeV with RHIC-STAR experiment, Mina Hatakeyama (University ofTsukuba)

2020.1.7

Azimuthal anisotropic flow of charged particles in Au+Au collisions at √𝑠with RHIC-STAR experiment, Yukiko Hoshi (University of Tsukuba)

56= 27 GeV2020.1.7

Reaction cross section measurements for proton-rich nucleus 17F using solid hydrogentarget, Reo Kagesawa (University of Tsukuba)

2020.1.7

Variations of cosmogenic Be-10 and Cl-36 in rainwater with cosmic-ray intensity, Yuta
Ochiai (University of Tsukuba)

57

7.
THESES

Writing down the new findings

Master theses

Miya Hashimoto

Measurement of trace-iodine isotope in the environment using mass spectrometryapplication to marine chemistry

Reo Kagesawa

Reaction cross section measurements for proton-rich nucleus 17F using solidhydrogen target

Yuta Ochiai

Variations of cosmogenic Be-10 and Cl-36 in rainwater with cosmic-ray
intensity

Ruri Suganuma

Pulse height distribution of Channeltron signal for the detection of keVparticles

Undergraduate theses

Natsuko Kishi

Determination of Li depth profile by nuclear reaction analysis

Kaito Nishizuka

Reconstruction of 14C introduction history in the Japan Sea using a coral core sample

58

8.
LIST OF PERSONNEL

Emergency response training for the staff and students working in
the experimental facilities including UTTAC.

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 Staff

S. Kuramochi

Administrative Staff

M. Satoh

Administrative Staff

H. Muromachi

Administrative Staff

Research Members1
Division of Physics
A. Ozawa

T. Moriguchi

K. Sasa

M. MukaiT. Yamaguchi (Cross appointment from Saitama University)
Division of Applied Physics
E. Kita

D. Sekiba

A. Uedono

H. Yanagihara

S. Sharmin

S. Tomita

Division of Geoscience
M. Kurosawa
Department of Biology
I. Suzuki
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.

59

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])
Graduate students
Graduate School of Pure and Applied Sciences, and Graduate School of Life and Environmental Sciences
Y. LiuH. Onoda

H. Koizumi

Y. Sugisawa

Y. Ochiai

R. Kagesawa

K. Tomita

R. Suganuma

T. Itou

A. Ogura

N. Onozato

S. Yamada

M. Hashimoto

H. Yokoyama

R. MaseM. Inoue

W. UenoS. AndoR. AbeY. Takahara

R. Yaguchi

Y. Kurosaki

Undergraduates
A. Taira

N. Kishi

K. KimuraT. Okamoto

K. Nishizuka

Y. GaoD. Hirose

K. Sakakura

T. Narita

K. Yoshimura

External users and collaborators
Y. Iwata

National Institute of Advanced Industrial Science and Technology (AIST)

K. Tomita

National Institute of Advanced Industrial Science and Technology (AIST)

T. Ishizuka

National Institute of Advanced Industrial Science and Technology (AIST)

S. Shiki

National Institute of Advanced Industrial Science and Technology (AIST)

T. Matsunaka

Kanazawa University

Y. Inada

Saitama University

S. Hosoi

Saitama University

M. Sakaue

Saitama University

K. Yokota

Saitama University

D. Hamakawa

Saitama University

D. Kajiki

Saitama University

H. TouSaitama University

M. Fukami

Saitama University

F. Miyake

Nagoya University

K. Kanzawa

Nagoya University

60