UTTAC-92, 2023

UTTAC
ANNUAL REPORT 2022

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

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

UTTACANNUAL REPORT 2022
April 1, 2022 − March 31, 2023

UTTAC-92, 2023

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 describes annual research
activities at Tandem Accelerator Complex, Research Facility Center for Science andTechnology, University of Tsukuba.
Copyright © 2022 by Tandem Accelerator Complex, Research Facility Center for Scienceand Technology, University of Tsukuba and individual contributors.
All reports are written on authors’ responsibility and thus the editors are not liable forthe 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: Wearing antistatic gloves, engineers of UTTAC are laying
plastic optical fibers for enabling ethernet to be used on thehigh-voltage terminal of the 6MV tandem accelerator.

PREFACE
This annual report covers research and development (R&D) carried out at Universityof Tsukuba Tandem Accelerator Complex (UTTAC) during the fiscal year 2022 (1 April
2022 ~ 31 March 2023). The topics include not only accelerator-based R&D using the
6MV tandem and 1MV Tandetron accelerators, but also radioisotope-based R&D
employing positron annihilation spectroscopy and Mössbauer spectroscopy. The goodnews in FY2022 is that high school visitors are back as the nasty coronavirus has subsided.
September 1, 2023
Editorial board

High school students are listening to an explanation of the tandem accelerator from theengineer on the left．They are looking inside the accelerator tank using the virtual
reality system, putting on VR goggles.

-i-CONTENTS
1 ACCELERATOR OPERATION AND RELATED STUDIES
1.1

Accelerator operation 2022 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.2

Approach to possible maximum energies of low Z ions accelerated by the 6MV11tandem accelerator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

1.3

Production of a faint beam at the experimental room . . . . . . . . . . . . . . . . .

5

1.4

Gamma-ray measurements inside the acceleration tank of the 6MV tandem electrostatic accelerator at the University of Tsukuba . . . . . . . . . . . . . . . . . . .

2 NUCLEAR AND COLLISION-BASED RESEARCH

7
9

2.1

Search for magnetic moment of 30 P . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2

Nuclear data of 32 S(α, p)35 Cl observed at 0◦ by the experimental setup for T-ERDA 11

2.3

Cluster eﬀects on convoy electron yield of fast H+
2 at 292 keV/u . . . . . . . . . . . 13

2.4

Improvement of PIXE system using superconducting tunnel junction X-ray detectors 15

3 ACCELERATOR MASS SPECTROMETRY

9

16

3.1

Status report of the Tsukuba 6MV multi-nuclide AMS system in FY2022 . . . . . 16

3.2

Anthropogenic I-129 depositions at the Noto Peninsula since 1950 . . . . . . . . . 18

3.3

The performance of iodine-129 AMS measurements at the University of Tsukuba(FY2022) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

3.4

Investigation of Iodine-129 deposition from atmosphere in the sample preparation
rooms for AMS in Japan (FY2022) . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3.5

Chlorine-36 in an ice core from the H15 site in Dronning Maud Land, East Antarctica 24

4 MATERIALS RESEARCH
4.1

25

Impact of cation vacancies on leakage current on TiN/ZrO2 /TiN capacitors studied
by positron annihilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.2

Superparamagnetic relaxation of magnetic nanoparticles studied with Mössbauer
spectroscopy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.3

Magnetic properties of hexagonal CoFe nitrides studied by Mössbauer spectroscopy 29

4.4

Transmission ERDA of ubiquitous deuterium in H-containing materials . . . . . . 31

- ii -

4.5

Tracking 7 Li in all-solid-state batteries using NRA . . . . . . . . . . . . . . . . . . 33

4.6

Electrochemical route to quickly insulate photo-metalized YOx Hy (111) epitaxial
thin ﬁlms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.7

Study for hydrogen content for UCN storage. . . . . . . . . . . . . . . . . . . . . 37

5 ION-BEAM IRRADIATION EFFECT

39

5.1

Evaluation of LoRaTM transceiver and microprocessor toward space use . . . . . . 39

5.2

Evaluation of COTS electronic devices for space applications . . . . . . . . . . . . 41

5.3

Observation of nonreciprocal critical current in YBa2 Cu3 O7 ﬁlms irradiated with
75-MeV Au ions directed oﬀ-normal to the ﬁlm surface . . . . . . . . . . . . . . . . 43

5.4

Study on mutagenesis with 15 N-resonant nuclear reaction and radiation eﬀects . . 45

6 TECHNICAL REPORT

47

6.1

Development of the terminal vacuum gauge system . . . . . . . . . . . . . . . . . . 47

6.2

VR-techniques for electrostatic tandem accelerator . . . . . . . . . . . . . . . . . . 49

7 LIST OF PUBLICATIONS AND PRESENTATIONS

51

7.1

Peer-reviewed and proceedings papers . . . . . . . . . . . . . . . . . . . . . . . . . 51

7.2

Reviews and books . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

7.3

Poster and oral presentations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

7.4

UTTAC seminars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

8 THESES

59

9 LIST OF PERSONNEL

60- iii -

1.
ACCELERATOR OPERATION AND RELATED STUDIESAn engineer of UTTAC working for maintenanceand upgrading of the 6MV tandem accelerator.

1.1

Accelerator operation 2022

K. Sasa, S. Ishii, T. Takahashi, Y. Yamato, T. Yoshida, M. Matsumura, T. Moriguchi
University of Tsukuba Tandem Accelerator Complex (UTTAC) is promoting the maintenance andoperation of the tandem accelerator facility consisting of the 6MV Pelletron tandem accelerator and the
1MV Tandetron accelerator for cooperative researches both inside and outside the University of Tsukuba.
1MV Tandetron accelerator
The 1MV Tandetron accelerator with 2 negative ion sources and 4 beamlines was operated for a total of
42 days in FY2022. The operating time and the experimental beam time were 575.5 and 157.6 hours,
respectively, during the total service time in FY2022. A total of 37 experiments with 137 participants werecarried out using this accelerator. Figures 1 and 2 show classification of the accelerated ions and ofexperimental purposes, respectively. Note that for each pair of the monoatomic and diatomic beams their
total acceleration time is shown in Fig. 1 since the time for the two cases was hardly distinguished. Instabilityof the terminal voltage has been sometimes observed for this accelerator since 2022, probably due to agerelated deterioration of the voltage circuit.

C & C2
10.2%

Al & Al2 Si
2.0% 1.8%

Li & Li2
7.4%

Education
6.3%

Beam test
0.8%

Ion irradiation
1.0%

Biomedical
research
14.8%

H
27.1%
25.6%
Clusterphysics
51.5%
RBS/ERDA

He
51.5%

Fig. 2. Experimental purposes of the 1MV Tandetron
accelerator in FY2022.

Fig. 1. Accelerated ions by the 1MV Tandetron
accelerator in FY2022.

6MV Pelletron tandem accelerator
The 6MV Pelletron tandem accelerator with 5 negative ion sources and 12 beamlines was operated fora total of 103 days. Its operating time and the experimental beam time were 1,154.4 and 1,010 hours,
respectively, during the total service time in FY2022. The operating time decreased by about 20% comparedto the last fiscal year [1]. In FY2022, this accelerator was used for 11 research projects on campus and 7
research projects cooperating with facilities outside the campus. A total of 53 experiments with 307
participants were carried out using this accelerator. In May 2022, the terminal generator broke down, hence1the acceleration tank was opened for repairs, resulting in a period of approximately one month of inactivityof this accelerator. During the scheduled maintenance in March 2023, a new vacuum gauge was installed at
the terminal [2].
Figure 3 shows the beam time histogram with respect to the terminal voltage. Figures 4 and 5 showclassification of the accelerated ions and of the experimental purposes, respectively. The most frequently
used case was AMS for iodine-129 at the terminal voltage of 5 MV. In addition, nuclear experiments using
polarized deuterons from polarized ion sources were started in FY2022.

Terminal voltage (MV)

6
5
4
3
2
0.0

100.0

200.0

300.0
400.0
Beam time (hours)

500.0

600.0

Fig. 3. Beam time histogram as a function of the terminal voltage for the 6MV Pelletron tandem accelerator in FY2022.

Ion irradiation
4.9%
IBA（RBS/ERDA/
PIXE)
9.4%

Au
2.4%
H
18.8%

He
5.8%
Cl
16.4%
Cr
0.2%

Sc
0.2%

Developments(Instruments andDetectors)
0.8%

Beam test
1.1%

D
5.9%

I
48.4%

Education
0.7%

Nuclearphysics
19.2%

C
0.2%
O
0.3%

AMS
63.9%

F
S 0.3%
1.1%

Fig. 4. Accelerated ions for the 6MV Pelletron tandem
accelerator in FY2022.

Fig. 5. Experimental purposes of the 6MV Pelletron
tandem accelerator in FY2022.

References[1] K. Sasa et al., UTTAC Annual Report 2021, UTTAC-91 (2022) 1.
[2] Y. Yamato et al., this Annual Report 6.1.

2

1.2

Approach to possible maximum energies of low Z ions accelerated by the
6MV tandem accelerator

M. Sataka, T. Takahashi, H. Naramoto, H. Kudo, K. Sasa
Acceleration tests of ion beams obtained from the 6MV tandem accelerator at UTTAC have been
continued [1]. In this fiscal year, high-energy heavy ion beams were required for ion irradiation experiments
for material science such as ion beam modification of materials [2]. At UTTAC, very weak beams of highenergy low-Z ions are indispensable for radiation resistance tests of semiconductors used in space [3].
Chromium data were newly collected, while S, Cl and Sc data were updated. We have measured beam
currents of the accelerated ions as a function of the ion charge at an acceleration voltage from 3 to 6 MV.
Figure 1 shows the beam current distributions of Cr ion as a function of the ion charge at the maximum
terminal voltage of 6 MV. A carbon foil of ~5 µg/cm2 thickness was used as a stripper at the 6 MV terminal.
In this accelerator control system, the minimum measurable value of the Faraday cup current is 0.1 nA,
while measurement of lower current is needed for low Z ions. For this purpose, the bending magnets, lenses
and steerers were preset to the estimated values, thereby leading the ion beam to the end Faraday cup witha picoammeter at the experimental apparatus. Beam operation time was not significantly different from thatfor high-current ions. For measurement of extremely low current, a particle detector was used instead of apicoammeter.

Ion Currennt (nA)

100
10
1
0.1
0.01
0.001

5

6

7

8

9

10

11

12

13

14

15

Charge State
Fig. 1. Beam current distribution of Cr ion at the terminal voltage of 6
MV. A foil stripper was used at the high voltage terminal.

Table 1 shows the beam current distribution of ions which were produced from molecular ions. In thiscase, the accelerated ion energy cannot be determined only by the terminal voltage and the ion charge after
acceleration. Table 2 shows the ion charges and maximum energies obtained for injection of negative atomic
ions at the terminal voltage of 6 MV. Tables 1 and 2 show the data accumulated from 2016 to 2022.

3

Table 1. Beam current distributions for molecular ion injection at the terminal voltage of 6 MV,
which have been accumulated since 2016. The measured beam intensity is shown by the symbols:○: ≥ 1 nA, △: ≤1 nA. Shown in red were obtained by using foil strippers.
charge

state

N

Al

Ca

Sc

Ti

Mo

W

14
13

△

12
11
10
9
8

○

7

△

○

△

○

△

○

○

△

△

△

○

○

○

○

△

○

○

○

○

○

△

○

○

○

6

△

○

△

○

○

○

5

○

○

△

○

○

○

4

○

○

○

○

○

3

○

○

○

○

2

○

△

1

Table 2. Summary of the acceleration tests from 2016 to 2021 for negative atomic ion
injection at the terminal voltage of 6 MV. The measured beam intensities are shownby the symbols: ○: ≥1 nA, △: ≤1 nA. Shown in red were obtained by using foil strippers.

charge energy

state （MeV） H

He

Li

B

C

O

F

Al

Si

S

Cl

14

90

13

84

△

△

12

78

△

11

72

10

66

9

60

8

54

○

○

7

48

○

○

Sc

Br

Ag

I

△

△

○

△

△

△

△

○

△

○

○

○

○

○

○

○

○

○

○

○

○

○

○

○

○

○

○

○

○

○

△

○

○

○

○

○

○

○

△

○

△

○

○

○

○

○

○

○

△

○

△

○

○

○

○

○

○

○

△

Cr

Fe

Ni

△

△

△

△

○

△

△

○

△

△

△

△

○

○

○

○

△

○

○

○

○

○

○

○

○

○

○

○

○

Cu

6

42

○

○

○

○

○

○

○

○

○

○

○

○

5

36

○

○

○

○

○

○

○

○

○

○

○

○

○

4

30

○

○

○

○

○

○

○

○

○

○

○

○

3

24

○

○

○

○

○

○

○

○

○

○

○

2

18

○

○

○

○

○

○

△

○

○

1

12 ○

○

○

References[1] M. Sataka et al., UTTAC Annual Report 2021, UTTAC-91 (2022) 3 and references therein.
[2] H. Matsui et al., this Annual Report 5.3.
[3] H. Kukita et al., this Annual Report 5.2.

4

Ta

Au

1.3

Production of a faint beam at the experimental room

T. Moriguchi, M. Sataka, S. Ishii, T. Takahashi, T. Yoshida, A. Yano
For research and development of detectors with ion beam irradiation, adjustment of the beam intensity
is necessary to evaluate the correct performances of the detectors without radiation-induced deteriorations.
So far, in the detector tests using ion beams supplied by the 6MV Pelletron tandem accelerator, the beam
intensity was attenuated using elastic scattering of ions when they pass through a thin foil of gold, forexample [1-4]. In this method, the beam suffers degraded beam emittance and energy struggling, hence othermethod to obtain a faint beam is required for detector tests. In FY2022, we attempted to produce a faintbeam at the experimental room often used for nuclear experiments and detector tests.
We started by transporting 12-MeV protons of maximum intensity to the A7 course in the experimentalroom.

At this time, the typical beam current at the Faraday-cup of the A7 course (IA7-FC) was 58 nA.

Inserting an attenuator upstream of the accelerator (Attup), IA7-FC was reduced to ~1 nA. After closing the
low-energy beam slits (LE-slit) to the lower limit, indicating the 1.0-mm squared aperture, IA7-FC was
reduced to ~4 pA. To defocus the beam, we stopped the current of the quadrupole magnet in the A7 course(QMA7), which is the most downstream quadrupole magnet in the beam line. After defocusing, the beam
count rates at the A7 course (IA7-PL) was ~60 kcps, which was measured by a plastic scintillation counter(PL) located at the end of the A7 course in the air. Note that such a beam current is too low to measure witha Faraday cup. Moreover, we used one of the additional attenuators (Attdown), which consist of a total of 16
meshed foils installed in the foil changer unit just downstream of the accelerator. Using the Attdown of #16
as the typical case, we obtained IA7-PL~700 cps, indicating successful production of the faint beam. Table 1
is a list of the beam intensities at each process for the production of the faint beam. For the fine adjustmentof IA7-PL, it is effective to tune the currents of the quadrupole magnets, with a selection of suitable Attdown.

Table 1. Typical beam intensities of 12-MeV protons at each process for the productionof the faint beam. IA7-FC and IA7-PL indicate the beam current obtained from the Faraday
cup and the beam count rates obtained from the plastic scintillation counter, respectively,in the A7 course.
Attenuation rate
Maximum beam intensity

IA7-FC

IA7-PL

58 nA

3.6×1011 cps*1

w/ Attup~ 1/50

1 nA

6.3×109 cps*1

w/ LE_Slit close~ 1/250

4 pA

2.5×107 cps*1

w/ QMA7 off~ 1/400−

60 kcpsw/ Attdown~ 1/100*2−

700 cps*1: Converted from the IA7-FC. *2: Depending on the selected attenuator.

5

Figure 1 shows the energy spectrum of protons measured by a round shaped silicon detector (ORTEC,
BA-24-150-1000), whose active area and sensitive depth are 150 mm2 and 1000 µm, respectively. The
silicon detector was installed in the scattering chamber of the A7 course, and irradiated directly with 12MeV protons (IA7-PL ~700 cps). As shown in Fig. 1, the energy peak of protons (FWHM ~20 ch) is clearlyseen without remarkable pileup, while there are low-energy events resulting from the beam irradiation. We
will use the faint beams for the detector tests in the future.

10000

(a)

10000

Yield [counts/ch]

Yield [counts/ch]

100000

1000
100
10
1

0

8000

(b)

6000
4000
2000
0
2690 2710 2730 2750 2770

1000 2000 3000 4000

Energy [ch]Energy [ch]Fig. 1. (a) Typical energy spectrum for the faint beam of 12-MeV protons. (b) Enlarged peak area ofthe same spectrum shown in the linear scale.

References[1] T. Yamaguchi et al., UTTAC Annual Report 2017, UTTAC-87 (2018) 9.
[2] T. Yamaguchi et al., UTTAC Annual Report 2018, UTTAC-88 (2019) 8.
[3] S. Y. Matsumoto et al., UTTAC Annual Report 2020, UTTAC-90 (2021) 12.
[4] T. Yamaguchi et al., UTTAC Annual Report 2021, UTTAC-91 (2022) 12.

6

1.4

Gamma-ray measurements inside the acceleration tank of the 6MV
tandem electrostatic accelerator at the University of Tsukuba

H. Matsumura1, M. Matsumura, G. Yoshida1, T. Moriguchi, K. Sasa
The 6MV Pelletron tandem electrostatic accelerator (18SDH-2, National Electrostatics Corp.) has been
installed at the University of Tsukuba Tandem Accelerator Complex (UTTAC) and has been in operation
since 2016 [1]. This accelerator is used for various researches, in particular, the largest percentage of theaccelerator operating time is occupied by AMS [2]. The accelerator system consists of ion sources, anaccelerator tank, beamline components, which are surrounded by the concrete wall of the accelerator room.
Determining which parts of the accelerator are activated will be helpful for future decommissioning of theaccelerator. Because of the particularly large volumes of the acceleration tank and accelerator room concrete,decontamination will be very hard and expensive if these parts become radioactive. Therefore, there is greatinterest in whether they will be activated or not, hence we investigated previously the activation of theaccelerator facility at UTTAC [35].
Among the particle beams accelerated by the tandem accelerator at UTTAC, the proton beam accelerated
up to 12 MeV is most serious for activation. Strong activation is induced by nuclear reactions with primary
protons at the beam loss point. In addition, the neutrons produced by the primary nuclear reactions activate
the surrounding materials after thermalization. In our previous study, several strongly activated regions wereobserved on the beamline immediately after acceleration of the proton beam [3]. We also measured thefluence rate of thermal neutrons in the accelerator room and concluded that the accelerator room concrete is
not activated even after 30 years of operation [4]. Similarly, the thermal neutron fluence rate on the surfaceof the acceleration tank during the operation was measured in a previous study [5]. The measured results
inferred that the acceleration tank was not activated. In the present study, as further investigation, γ rays
were measured inside the acceleration tank to confirm that there were no activation points.
On May 23, 2022, 26 days after the last accelerator operation (and, in particular, 45 days after theactivatable 12-MeV proton beam operation), γ rays were measured in the acceleration tank using a NaI
scintillation survey meter (manufacturer: Aloka, model: TCS-161, and detector crystal: 1-inch NaI(Tl)scintillator) and a LaBr3 scintillation spectrometer (TechnoAP, TS-100, and 1-inch LaBr3(Ce) scintillator).
First, a radiation survey in the entire acceleration tank was performed using the NaI scintillation survey
meter. Gamma radiation dose levels for all objects were at the background level, and no activation wasobserved anywhere. Next, γ-ray spectra were obtained using the LaBr3 scintillation spectrometer for more
precise evaluation at the three typical locations (Locations A, B, and C) shown in Fig. 1, where the beamloss was likely to occur. The measurement time was 5 minutes. Photos of Locations A, B, and C are shownin Fig. 2. A background spectrum was also obtained on the bottom of the acceleration tank at Location D,
shown in Fig. 1, upstream of the beam line, where activation cannot occur due to the low beam energy. The
measurement time at Location D was 5 minutes, same as for Locations A, B, and C. A photo of the

1High Energy Accelerator Research Organization (KEK)7background measurement at Location D is shown in Fig. 2.
Figure 3 shows comparison of the γ-ray spectra measured at Locations A, B, and C with the backgroundγ-ray spectrum obtained at Location D. As shown in Fig. 4, all γ-ray spectra agree with the background
spectrum. The peak counts for 54Mn, 56Co, 58Co, and 60Co, which are possible nuclides, were analyzed, andthe results were within the errors. As expected from the results of the previous study, the absence ofactivation of the acceleration tank was confirmed in the present investigation. The results of this series ofactivation investigations performed at UTTAC will be helpful for the future decommissioning of this facility.

B

A

D

C

Fig. 1. Locations A, B, C, and D. A: near the stripper foil, B: upstream of the outlet duct, C: downstream frame,
and D: upstream tank bottom.

Beam

A

B

Beam

Beam

C

D

Fig. 2. Locations A, B, C, and D where γ-ray spectra were measured with the LaBr3 scintillation spectrometer.
1

Location C

at Location A
at Location D (background)at Location B
at Location D (background)at Location C
at Location D (background)

200

400

600

800

Energy (keV)

1000

1200

1400

cps /chLocation B

0.1

0.01
0

1

Location A
cps /chcps /ch

1

0.1

0.01
0

200

400

600

800

Energy (keV)

1000

1200

1400

0.1

0.01
0

200

400

600

800

Energy (keV)

1000

1200

Fig. 3. Comparison of the γ-ray spectra measured at Locations A, B, and C (red) with the background (black).

References[1] K. Sasa et al., UTTAC Annual Report 2016, UTTAC-86 (2017) 1.
[2] K. Sasa et al., UTTAC Annual Report 2021, UTTAC-91 (2022) 1.
[3] G. Yoshida et al., Radiation Safety Management 20 (2021) 1.
[4] H. Matsumura et al., Radiation Protection 40 (2020) 667.
[5] H. Nakamura et al., Environmental Radiochemical Analysis VI (2019) 152.

8

1400

2.
NUCLEAR AND COLLISION-BASED RESEARCH

Measuring the nuclear magnetic moment of unstable nuclei.
−−− Report 2.1

2.1

Search for magnetic moment of 30P

A. Ozawa, T. Moriguchi, Y. Yamato, A. Yano, Y. Seki
Nuclear magnetic moment (µ) is very sensitive to nuclear structure. It gives detailed information about
the single particle nature and its shell structure. Thus, it is important to measure µ also for unstable nuclei.
Among the nuclei, odd-odd N=Z nuclei are of special interest. In this case, by using the observed magnetic
moment and β -decay life-time, it is possible to deduce the matrix element for spin operators for zero isospin(T=0). It is also interesting whether the odd-odd N=Z nuclei may have the deuteron-like structure. Amongthe odd-odd N=Z nuclei in the light mass region (A<40), µ of 30P (Iπ=1+, T1/2=2.50 min) is unknown. This
nucleus is located in the middle of sd shell region. Thus, this nucleus may be deformed. In this case, single
particle nature is not anticipated. Therefore, to investigate the nuclear structure of 30P, it is important tomeasure µ for 30P.
Until now, we succeeded in the production of 30P by using two primary beams; one is by using polarized
proton beams with Si target (30Si(p,n)30P reaction) and the other is by using polarized deuteron beams with
Si target (29Si(d,n)30P reaction). Typical β -ray time spectrum for measurements using polarized proton beams(12 MeV) with Si (n-type, low-impedance) is shown in Fig. 1 (a). On the other hand, typical β -ray time
spectrum for measurements using polarized deuteron beams (6 MeV) with Si (p-type, high-impedance) isshown in Fig. 1 (b). In both of the figures, a large amount of 30P can be recognized. However, as the background, a large amount of 29P (Iπ=1/2+, T1/2=4.14 s) is also seen. Since µ of 29P is known, we can check thepolarization degree corresponding to the above conditions. Typically, the observed polarization of 29P isroughly 1% for the polarized proton beams (Ep=12 MeV) and roughly 5% for the polarized deuteron beams(Ed=6 MeV) with the Si target. Since the atomic number of 29P and 30P is the same (Z=15) and the mass
number is very close, it is expected that location of 30P after the reaction is the same as that of 29P in Si. Thus,
it is expected that 30P is also polarized with the polarized proton and deuteron beams. On the other hand,compared with 29P, a large amount of polarization is not anticipated in 30P since its life time is very long
(2.50 ms) and the relaxation time of polarization in Si is only 22(2) s, that was determined for 29P [1]. The
spin of 30P (1+) may induce electric quadrupole interaction in the Si target, which may destroy the nuclear
polarization of 30P faster than that of 29P.
The beam energy is a parameter of importance to produce the nuclear polarization. In the (p,n) reaction,
the proton beam energy corresponds to the states in the produced nucleus. In some cases, very large energy
dependence of polarization is observed [2]. Thus, it is important to change the beam energy. In FY2022, wesearched µ of 30P by using the polarized proton beams (Ep=7, 7.5, 8, 8.5, 9 and 10 MeV) and the polarized
deuteron beams (Ed=6, 8, 10 and 12 MeV). We searched µ of 30P from 0.2 to 0.9 n.m.. Within this range, µof deuteron (µ=0.857 n.m.), typical prediction by the shell model (µ=0.70~0.83 n.m. [3]) and the prediction
by three-body model calculations (µ=0.318 n.m. [4]) are included. In measurements in FY2022, we could
not observe significant effect for 30P. We will continue the measurements by changing the energy of the
primary beams.

9

Fig. 1. (a) Typical time spectrum of β -rays for Si (n-type, low-impedance) irradiated by a polarized
12-MeV proton beam. The solid and broken lines correspond to the decay for 29P and 30P,
respectively. The dashed line corresponds to the decay for 25Al (T1/2=7.18 s), that is produced by
28

Si(p,α)25Al reaction. (b) Typical time spectrum of β -rays for Si (p-type, high-impedance)

irradiated by a polarized 6-MeV deuteron beam. The solid and broken lines correspond to the decayfor 29P and 30P, respectively.

References[1] T. Minamisono et al., Phys. Rev. C 14 (1976) 376.
[2] T. Minamisono et al., Phys. Rev. C 14 (1976) 2335.
[3] P. W. M. Glaudemans et al., Annals of Phys. 63 (1971) 134.
[4] Y. Tanimura et al., Prog. Theor. Exp. Phys. (2014) 053D02.

10

2.2

Nuclear data of 32 S(α , p)35 Cl observed at 0◦ by the experimental
setup for T-ERDA

H. Kudo, H. Naramoto, M. Sataka, S. Ishii, K. Sasa, S. Tomita
As a by-product of hydrogen analysis of PPS, polyphenylene sulﬁde (C6 H4 S)n , by transmission ERDA[1], the 32 S(α , p)35 Cl reaction at 0◦ has been observed. The PPS sample of 1.35 µ m thickness was underlaid
with a Ni foil of 20 µ m thickness to prevent the incident 8 MeV 4 He2+ from entering the particle detector.
In the measured ERDA spectrum, shown in Fig. 1, we see three sharp peaks indicated by p0 , p1 , and p2 , thelatter two of which are superimposed on the tail of the large peak of recoil hydrogen at 4.2 MeV. From theenergy shift of the prominent p0 peak measured for the Ni foil of 25 µ m thickness, we found that the peak isdue to protons emitted from the PPS ﬁlm. Indeed, the protons result from the 32 S(α , p0 )35 Cl reaction with
the Q value equal to −1.866 MeV [2], where the subscript of p0 represents the p-emission with the nuclear
transition to the ground level of 35 Cl.

Yield (counts/channel)

500
400

32

S(α, pn)35Cl
8.00 MeV He
7.90 MeV He

p1
p0

300
p2

200
100
0
2.0

2.5

3.0

3.5 4.0 4.5
Energy (MeV)

5.0

5.5

Fig. 1. Energy spectrum of protons escaped from PPS/Ni(20) in the 0◦ direction. The calculated peakenergies due to the nuclear reaction at the PPS surface (8.00 MeV He) and backsurface (7.90 MeV He) are
shown by the red and blue arrows, respectively. The red dashed lines indicate the assumed baselines of thethree peaks.

On the PPS surface, the reaction induced by 8.00 MeV 4 He produces 5.83 MeV protons in the 0◦ direction, which is concluded from the conservation of momentum and energy including the Q value. On the PPS
backsurface, 7.90 MeV He produces 5.74 MeV protons in the 0◦ direction. The energies of these protons
after escaping from the backsurface of Ni(20), which were calculated using the SRIM code, are indicatedby red and blue arrows in Fig. 1. The corresponding energies for protons of p1 and p2 which result fromtransitions to the ﬁrst (1.22 MeV) and the second (1.76 MeV) excited levels of 35 Cl, respectively, are also
indicated in Fig. 1. The peaks for pn (n ≥ 3) were hardly recognized in the present experiments. We seein Fig. 1 that the observed peaks of p0 , p1 , and p2 are produced mainly from the nuclear reaction near thebacksurface of PPS, i.e., by 7.90 MeV He. This is consistent with the observations by Soltani-Farshi andcoworkers, in which the differential cross section of the 32 S(α , p0 )35 Cl reaction for 7.90 MeV He is larger

11than for 8.00 MeV He in the 60–167◦ angular range of observation [3].
From the present experimental data, the differential cross section of the 32 S(α , pn )35 Cl reaction at 0◦
for n = 0, 1, 2 can be determined. To do this, it is necessary to investigate whether the amount of S in the
PPS ﬁlm changes under the He2+ irradiation. Actually, the p0 peak remained unchanged for incident He2+
charges of 4 µ C and for additional 4 µ C afterwards, indicating a ﬁxed amount of S during the measurements.
The reaction yield Yn , equal to the area under the pn peak, can be obtained by assuming the baselines
shown in red dashed lines. Yn is related to the differential cross section dσn /dΩ by
Yn = NHe NS

dσn× ∆Ω ,dΩ(1)

where NHe is the number of incident He2+ , NS is the area density of S in the PPS ﬁlm viewed along the beamaxis, and ∆Ω = 0.01367 sr. is the solid angle of acceptance, which corresponds to the angular range of 0
to the detector’s acceptance angle of 3.78◦ . In the present case, NHe = 2.483 × 1013 and NS = 1.102 × 1018
cm−2 for PPS of 1.35 µ m thickness. The results obtained from Eq. (1) are summarized in Table 1.
Table 1. Differential cross sections of the 32 S(α , pn )35 Cl reaction at a recoil angle of 0◦ , determined for the
He energy range of 7.90–8.00 MeV.

pn

Yn (counts)

dσn /dΩ (mb/sr)

p0

2875

7.69 ± 0.14

p1

827

2.21 ± 0.13

p2

716

1.92 ± 0.12

Notably, the value of 7.69 ± 0.14 mb/sr for p0 is in the same range of 5–10 mb/sr as for the reported
differential cross sections [3]. The present data at a recoil angle of 0◦ provide additional knowledge about
the 32 S(α , pn )35 Cl reaction.
References[1] H. Kudo et al., J. Phys.: Condens. Matter 34 (2022) 435902.
[2] P. Mohr, Eur. Phys. J. A 5 (2015) 56.
[3] M. Soltani-Farshi et al., Nucl. Instrum. Meth. Phys. Res. B 113 (1996) 399.

12

2.3

Cluster effects on convoy electron yield of fast H2+ at 292 keV/u

S. Hatada, G. Kawasaki, M. Hiraga, Y. Shiina 1, S. Ishii, T. Takahashi, K. Sasa, S. Tomita
When fast molecular ions are incident on a material, the constituent atoms of the molecular ion impingeon a narrow range of the material simultaneously. In this case, the interatomic distances of the impinging
atoms may be considered to be shorter than the impact parameter for the collective electron excitation in thematerial. Therefore, the response of electrons by molecular ion injection should differ from that by singleatomic ion injection. Such phenomenon is known as the cluster effect. In fact, the electronic energy loss ofa fast atomic ion injected as a constituent of a molecular ion is distinct from that of a single atomic ion. Thisdifference is due to the interference of the collective electron response caused by the individual constituent
atoms of the incident molecular ion [1].
A cluster effect resulting from the electron response of the material has been reported previously,
indicating a significant reduction in the secondary electron yield [2] and a substantial enhancement in the
convoy electron yield for C2+ at 42 keV/u and 292 keV/u [3, 4]. This effect is believed to stem from thedifference in the transport processes of scattered electrons in the material. Understanding this cluster effectcould provide valuable insight into the radiation damage of biomolecules such as DNA molecules, as
scattered electrons and other radicals generated by the penetration of fast-charged particles can causeradiation damage. To examine the dependence on the effective charge of the projectile ion, we measured thecluster effect of convoy electron yield for H2+ at 292 keV/u.
A series of experiments has been conducted using the 1MV Tandetron accelerator at UTTAC. The H2+ions were accelerated and transported to the experimental chamber, where they penetrated thin carbon foils
provided by ACF-Metals, The Arizona Carbon Foil Co., Inc. The nominal thicknesses of the foils used in
the experiments are 11.2, 19.3, and 59.8 µg/cm2. A 45° parallel-plate electrostatic spectrometer of double
deflection type with a 3% energy resolution was used to analyze the energies of electrons emitted in the
beam direction. The electrons were counted by a Channeltron detector whose anode potential was carefully
set to +100V to obtain the maximal detection efficiency. To cancel out geomagnetism, a triaxial square
Helmholtz coil surrounded the experimental chamber. The energy spectra were accurately normalized with
the number of signals of backscattered ions from the bulk Au target, which was periodically inserted on thebeamline.
Figure 1 shows energy spectra of the secondary electrons emitted from the carbon foil of 11.2 µg/cm2,
resulting from penetration of 292 keV/u H+ and H2+ ions. The convoy electrons can be recognized at
approximately 150 eV, hence the convoy electron yield is obtained by the area under the convoy peak.

Itshould be noted that no essential difference is perceived between the convoy electron yields per atom
induced by H+ and H2+. Figure 2 shows dependence of the ratio of the convoy electron yield per constituent
H atoms on the carbon foil thickness, together with the previous data for C+ and C2+. Again for H+ and H2+,
there is only a minor difference between the convoy electron yields for the foil thicknesses of 19.3 or 59.8

1R ikkyo University13µg/cm2, in contrast to the case of C+ and C2+. As the target becomes sufficiently thick, multiple collisions
with the target atoms primarily determine the interatomic distances between the injected atoms. According
to the TRIM simulation of atomic ion injection, the interatomic distance for H2+ is shorter than that of C2+.
These results indicate importance of the effective charge of the constituent atom in considering the cluster
effect on the convoy electron yield.

Fig. 1. Energy spectra of zero-degree electrons emitted from a carbon foil of 11.2 µg/cm2 in thickness.

2.4

Y (H2+) / 2Y (H+)

Ratio of convoy electron yield

2.2

Y (C2+) / 2Y (C+)

2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

Foil thickness (µg/cm2)

Fig. 2. Dependence of the ratio of the convoy electron yield per constituent atom on the carbon

foil thickness. The incident energy of the dimer and monomer ions of H and C is 292 keV/u.
References[1] W. Brandt et al., Phys. Rev. Lett. 33 (1974) 1325.
[2] H. Arai et al., J. Phys. Soc. Jpn. 78 (2009) 104301.
[3] S. Tomita et al., Phys. Rev. A 73 (2006) 060901.
[4] Y. Shiina et al., Nucl. Instr. Meth. Phys. Res. B 460 (2019) 30.

14

2.4

Improvement of PIXE system using superconducting tunnel junction
X-ray detectors

S. Shiki1, S. Tomita, S. Ishii, S. Hatada, K. Sasa
Superconducting tunnel junction (STJ) detector is promising for soft X-ray spectroscopy due to its highsensitivity, high energy resolution, and high counting rate [1]. Particle Induced X-ray emission equippedwith SuperConducting tunnel junction detector array (SC-PIXE) will expand the energy coverage of PIXE
down to the soft X-ray region where light elements are visible. The detection of Al-K line was reported withan energy resolution of 50 eV full width at half maximum (FWHM) using the SC-PIXE [2]. However, it
was difficult to observe light elements having K-lines at energies less than 1 keV, because the pulse heightspectrum was polluted by the events caused by scattered protons in the sample. Therefore, thin samples areused to reduce scattered protons.
The SC-PIXE system is placed in the μ-PIXE beam line at UTTAC [3]. The details of the experimentare as follows. The STJ spectrometer consists of a helium three cryostat, an STJ detector array of 512 pixels,
16-channel charge sensitive amplifies, and multichannel
analyzer having 16-inputs. The temperature of the cold
stage was approximately 320 mK. The beam current of 4
MeV H+ was 1−10 nA. The distance from the beam spot
to an STJ detector is approximately 100 mm. The sample
is 7.5 μm thick polyimide.
Figure 1 shows a pulse height spectrum of an STJ
pixel. The spectrum shows a clear peak at a pulse heightof ~143 channel. This peak is due to the C-Kα line. Theenergy resolution is 21 eV in FWHM, which is better
than that of silicon drift detectors.

Fig. 1. Pulse height spectrum of an STJ pixel. The
sample is 7.5 μm thick polyimide. The main peakis due to the C-Kα line.

References[1] S. Shiki et al., J. Low Temp. Phys. 167 (2012) 748.
[2] S. Shiki et al., UTTAC Annual Report 2021, UTTAC-91 (2022) 16.
[3] A. Yamazaki et al., Nucl. Instr. Meth. Phys. Res. B 404 (2017) 92.

1National Institute of Advanced Industrial Science and Technology (AIST)

15

3.
ACCELERATOR MASS SPECTROMETRY

Processing of seawater samples for I-129 measurement.
The seawater data is complementary with the data of
the lake sediments.
−−− Report 3.2

3.1

Status report of the Tsukuba 6MV multi-nuclide AMS system in FY2022

K. Sasa, T. Takahashi, M. Matsumura, A. Sakaguchi, T. Matsunaka 1
The Tsukuba 6MV multi-nuclide AMS system was operated for a total of 40 days and 645.4 hours in FY
2022. Figure 1 shows monthly-measured rare nuclides from April 2022 to March 2023. We measured 579
samples in total dealing with rare radionuclides such as 36Cl and 129I, as shown in Table 1.
120

Cl-36

I-129

Number of pieces

100
80
60
40
20
0

Apr-22 May-22 Jun-22

Jul-22Aug-22 Sep-22

Oct-22 Nov-22 Dec-22 Jan-23 Feb-23 Mar-23

Monthly measured nuclides
Fig. 1. Monthly-measured nuclides from April 2022 to March 2023.
Table 1. Number of measured 36Cl and 129I samples in FY2022.

Item
Cl-36
I-129
Sub total

36

Reagent & Blank
samples
11
51
62Standard samples

Analyzed samples

16
50
66

45
406
451

Total
72
507
579

Cl-AMS
36

Cl-AMS has been performed under the beam condition of 36Cl7+ with 48.0 MeV using a carbon foil

stripper at the terminal voltage of 6 MV. The background ratios of 36Cl/Cl ~ 3 × 10−15 were achieved with
AgCl blank samples. In FY2022, 36Cl-AMS was mainly applied for tracing anthropogenic 36Cl in an ice corefrom the H15 site in Dronning Maud Land, East Antarctica. We have been able to obtain a detailed recordof the variability of 36Cl produced by nuclear bomb tests [1].
129

I-AMS
129

I-AMS has been performed under the beam condition of 129I5+ with 30.0 MeV using an Ar gas stripper

1Kanazawa University

16

at the terminal voltage of 5 MV. The background ratios of 129I/I ~ 2 × 10−14 were achieved with AgI blanksamples prepared from “Old iodine” (Deepwater Chemicals). Anthropogenic radioactive 129I is used as anenvironmental isotope tracer. In FY2022, 129I-AMS was mainly applied to 129I tracer studies for soil andriver samples related to the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident and ocean circulation
studies in the Southern Ocean [2].
In 2023, ALPS-treated water stored at the FDNPP is to be discharged into the sea surrounding the plant.
We have started to check 129I concentrations in sea water, relating to ALPS-treated water around the FDNPP.
The purpose of this study is to clarify the temporal changes in the concentration of 129I in seawater andsediments that could be caused by the discharge of ALPS-treated water to the sea, and to evaluate the impact.
Measurement history

Number of AMS measuring samples

1200
Be-10

C-14

Al-26

Cl-36

Ca-41

Sr-90

I-129

1000
800

484
88

600
400
200

184
30
321
13

0

294

143

FY 2016

119322

FY 2017

257
29

29

196

165

23

187

180 13
FY 2018

85
FY 2019

Fiscal year

507

427

377
29
FY 2020

42
FY 202172
FY 2022

Fig. 2. Cumulative number of measured samples for AMS since 2016.

Figure 2 shows the cumulative number of measured samples since the AMS system started operation. A
total of 4,616 samples was measured from FY2016 to 2022. AMS of the radioactive halogens 36Cl and 129I
has been the main focus at the Tsukuba 6MV multi-nuclide AMS system since FY2020. Currently, AMS
developments are underway for 135Cs (a half-life of 2.3 million years) and 210Pb (a half-life of 22.2 years) as
new nuclides. We developed the rubidium (Rb) sputtering negative ion source by replacing Cs of the S-5
ion source (MCG-SNICS) with Rb [3]. Sample chemistries and additives are being developed for the 135Cs
and 210Pb samples to be loaded in the Rb negative ion source.
References[1] K. Horiuchi et al., this Annual Report 3.2.
[2] T. Matsunaka et al., this Annual Report 3.3.
[3] D. Shiine et al., UTTAC Annual Report 2021, UTTAC-91 (2022) 23.

17

3.2

Anthropogenic I-129 depositions at the Noto Peninsula since 1950

T. Matsunaka 1, S. Ochiai1, M. Matsumura, T. Takahashi, A. Sakaguchi, K. Sueki, K. Sasa
The investigation of water dynamics change in the Sea of Japan caused by the recent global warming isessential for forecasting the response of ocean circulation to climate change. Anthropogenic 129I (T1/2: 15.7
million years) produced from thermal neutron fission, is dominated by release from nuclear fuelreprocessing plants in Europe and supplied at the Sea of Japan via atmospheric deposition, surface runoff,and oceanic current. The long-lived 129I is expected as an oceanic tracer of surface and vertical circulationsin the Sea of Japan. This study aimed to illuminate the historical change of 129I deposition around the Sea ofJapan since 1950 through the analysis of 129I in lake sediments from the Noto Peninsula facing the Sea ofJapan.
Lacustrine sediment core collected in 2011 from the Noto Peninsula, divided into 1 cm pieces, was used
for the analysis of 210Pb, 137Cs, and 129I. Homogenized dried sediments (dry weight: about 1.5 g) were sealedin plastic containers, and 210Pb and 137Cs were measured using a Ge semiconductor detector at Low Level
Radioactivity Laboratory (LLRL), Kanazawa University. Extraction and purification of 129I in the sediments
by thermal hydrolysis and solvent extraction were carried out at LLRL. After isotope dilution by adding 1
mg of 127I carrier (Deepwater iodine, 129I/127I: ~1×10–14) to an alkaline solution with trapped combustion gas
produced from the sediment (0.5 g), iodine was purified by solvent extraction and back extraction and AgI
targets were prepared by adding AgNO3. The AgI precipitate was then washed with NH4OH and ultra-purewater and dried and loaded into an Al holder with Nb powder. The 129I/127I ratio of the target was measured
using the AMS system at the University of Tsukuba. A terminal voltage of 5 MV and a charge state of 5+
were chosen for acceleration and detection. The measured ratios were normalized against the Purdue-1
reference material, which has a 129I/127I ratio of 8.37 × 10–12 and is obtained from Purdue University, USA.
127

I in the alkaline solution was measured by ICP–MS. The original 129I/127I ratios and 129I concentrations inthe sediment were calculated using 127I concentration from ICP-MS and the 129I/127I ratio from AMS.
Excess 210Pb (210Pbex) concentrations in the sediments range from 84.2–739 Bq kg–1 from the surface toa depth of 29 cm and are undetectable deeper than 29 cm. Depth profiles of 210Pb ex with mass depth(g cm–2) were analyzed for sedimentation rates, i.e., 0.836 g cm–2 yr–1 (0–7.5 cm), 0.0638 g cm–2 yr–1 (7.5–
15.5 cm), 0.219 g cm–2 yr–1 (15.5–24.5 cm), and 0.0332 g cm–2 yr–1 (24.5–29.0 cm) (Fig. 1). The Cs-137
concentration ranges from 8.6–71.2 Bq kg–1 (decay-corrected to the sampling date) from the surface to adepth of 29 cm, with a maximum at a depth of 26–27 cm formed in 1962 (Fig. 1). Deposition of 129I in thelake sediments was in the range 0.004–77.8 nBq cm–2 yr–1 (129I activity: 0.13–93.0 µBq kg–1) and increased
after 1946, with the maximum levels being recorded in 1980 and 2011 (Fig. 2). These distributions revealed
an increase of atmospheric 129I deposition around the Sea of Japan related to nuclear fuel reprocessing since1950 and a nuclear accident in 2011.

1Kanazawa University

18

Fig. 1. Depth profiles of 210Pbex and 137Cs activity for the 63-cm-long lacustrine
sediment collected from the Noto Peninsula.

Fig. 2. Depth profiles of 129I flux for the 63-cm-long lacustrine sedimentcollected from the Noto Peninsula.

19

3.3

The performance of iodine-129 AMS measurements at the University ofTsukuba (FY2022)

M. Matsumura, K. Sasa, T. Takahashi, A. Sakaguchi, T. Matsunaka1, K. Sueki
Continuing from 2017, we have reported the performance of 129I measurements by accelerator mass
spectrometry (129I AMS) [1, 2]. From April 2022 to March 2023, we measured 507 samples of 129I by
preparing the AgI targets, the details of which are shown in Fig. 1. The test samples were not only iodinetrapping-solutions, but also those chosen from natural environment such as sea, rain, river water, suspended
sand, and sediments. Figure 2 shows the measured blank values of AgI precipitated from carrier-reagent.
The machine background is estimated to be on the order of 10−15 in terms of the 129I/127I ratio, which is
sufficiently lower than the background level of the ratio of 2 × 10−14 for “old Iodine” provided from Deep
Water company, USA. However, the measured 129I/127I values in blanks sometimes ranged over ten times
higher than 2 × 10−14. One of the causes for this might be the memory effect. The rise in blank values in2018 and 2019 is most likely caused by this memory effect, however, this effect has been prevented by the
improved measurement schemes since 2020. This means that we can succeed in decreasing the memory
effect by improvements of the measurement method.

Fig. 1. Details of measured 129I
by the AMS system in fiscal 2022.

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

The measured 129I/127I values were normalized by using Standard Reference Material (SRM), Purdue-1
STD (Z94-0597) and Purdue-2 STD (Z94-0596) with an 129I/127I ratio of 8.378 × 10−12 and 6.540 × 10−11 [3](the value was revised in 2014 [4]), which was provided by the Purdue Rare Isotope Measurement
Laboratory (PRIME Lab) at Purdue University, USA. The routine measurement method of SRM is asfollows: SRM-AgI was divided into two or three target cathodes and each target was measured four times
with a measurement time of 2 min, while the measurement interval was three or four hours. The average
beam currents were 1.6 μA and 1.4 μA for Purdue-1 and Purdue-2, respectively. For each run, the first1

Kanazawa University

20

measurement was excluded from the data file since it was treated as “sputter-cleaning”. Figures 3 and 4 aretypical results of Purdue-1 measurements in the same beam time. In fiscal 2022, the resulting ratios with its
standard deviation (1σ) are (7.600 ± 0.459) × 10−12 (6.0%) and (5.927 ± 2.080) × 10−11 (3.5%) for Purdue-1(run number 747) and Purdue-2 (run number 54), respectively. The ratios of (average of measurement value)/ (nominal value) are 0.907 and 0.906 for Purdue-1 and Purdue-2, respectively, which are in good agreement.

Fig. 3. Typical results of 129I/127I ratio measured for
Purdue-1. The average ratio with the standard
deviation (1σ) was (7.163 ± 0.226) × 10−12 (3.2%)
at this beam time.

Fig. 4. Beam current during the measurements.
The average beam current was 2.9 μA at thisbeam time.

This work was supported in part by JSPS KAKENHI Grant Numbers 22H02001 and 22H04441.

References[1] K. Sasa et al., Nucl. Instrum. Meth. Phys. Res. B 437 (2018) 98.
[2] M. Matsumura et al., UTTAC Annual Report 2019, UTTAC-89 (2020) 16.
[3] P. Sharma et al., Nucl. Instrum. Meth. Phys. Res. B 123 (1997) 347.
[4] M. Caffee, (Purdue University), Private communication (2014).

21

3.4

Investigation of Iodine-129 deposition from atmosphere in the sample
preparation rooms for AMS in Japan (FY2022)

M. Matsumura, K. Sasa, T. Matsunaka 1, T. Takahashi, A. Sakaguchi, K. Sueki
Through the chemical treatment of samples with high 129I concentrations, the workspace used to prepare
samples tends to become gradually contaminated. Such contamination may lead to overestimated 129I inaccelerator mass spectrometry (AMS) analyses. Environmental contamination monitoring of 129I from theatmosphere in sample preparation rooms, as shown in Fig. 1, was performed at ten Japanese institutions, i.e.,
Japan Atomic Energy Agency (Aomori Research and Development Center), Japan Atomic Energy Agency(Tono Geoscience Center), Ehime University (Advanced Research Support Center), Fukushima University(The Institute for Environmental Radioactivity), Kanazawa University (Institute of Nature andEnvironmental Technology), Kumamoto University (Institute of Resource Development and Analysis),Okayama University (Neutron Therapy Research Center), Tottori University (Division of Radioisotope
Science Research Initiative Center), The University of Tokyo (Micro Analysis Laboratory, Tandem
accelerator), and University of Tsukuba. The sampling was carried out in July and August 2022, andFebruary 2023. The ambient level of atmospheric 129I in each room was estimated from the measured
concentrations in the alkali trap solutions [1−3]. The alkaline solutions in the sampling bottles were left for
two or three weeks. To check the difference in the 129I contamination risks from atmosphere between inside and127I measurement by ICP-MS∼100mL・ratio of 129I/127I(I = 1mg) ・concentration of 129I in
the trapping solution
experimental room

room

129I/127I measurement by AMS

outsideFig. 1. Iodine sampling from atmosphere into the alkaline solution. The “room” means an area untreatedchemically, while “experimental room” means such as a sample preparation room, an ICP-MS room, andan AMS-target preparation room.
1Kanazawa University

22

outside the facility, the sampling bottles were left at places outside the seven institutions, where the rainwater
never entered the bottles. The 129I contamination risk [atoms cm-2 day-1] was estimated from 129I concentration[atoms g-1]. The experimental procedure was similar to the previous case [1], except that we used a different
carrier reagent” Old Iodine” provided from Deep Water company, USA [2, 4], with an 129I/127I ratio of 2 × 10−14.

Figure 2 shows the monitoring results of the 129I contamination rates in the Japanese institutions,obtained in this manner. In most of the institutions, the amounts of 129I are on the order of 103 or 104 atoms
cm–2 day–1 in the rooms, which are one or two orders of magnitude lower than the environmental backgroundlevel, 3 × 105 atoms cm-2 day-1. In the two rooms of University of Tsukuba, the 129I contamination rates werehigher than the background level for the reason previously described [1−3]. A clear difference is not foundbetween the 129I contamination risks from atmosphere inside and outside. This suggests that the atmospheric129

I level in the nine institutions (A to I) is lower than the environmental background level 3 × 105 atoms

cm−2 day−1 [5], hence there is almost no 129I contamination risk of the samples from atmosphere.

I (atoms cm-2 day-1)

107
106

room, Jul. or Aug., 2022
room, Feb., 2023
experimental room, Jul. or Aug., 2022
experimental room, Feb., 2023
outside, Jul. or Aug., 2022
outside, Feb., 2023

background level in environment

105

129

104
103
102

A

B C D

E

F
facilityG

H

I

University of Tsukuba

Fig. 2. Measured 129I contamination rates from atmosphere at the institutions indicated anonymously
by A to I, except University of Tsukuba.

This work was supported in part by JSPS KAKENHI Grant Numbers 22H04441 and 22H02001.
References[1] M. Matsumura et al., Anal. Sci. 36 (2020) 631.
[2] M. Matsumura et al., UTTAC Annual Report 2020, UTTAC-90 (2021) 23.
[3] M. Matsumura et al., Proceedings of the 23rd Symposium on The Japanese Society of Accelerator
Mass Spectrometry Research (2022) 84.
[4] M. Matsumura et al., this Annual Report 3.3.
[5] M. Matsumura et al., Geochemical Journal 52 (2018) 155.

23

3.5

Chlorine-36 in an ice core from the H15 site in Dronning Maud Land,
East Antarctica

K. Horiuchi 1, K. Sato1, R. Yagihashi1, K. Sasa, M. Matsumura, T. Takahashi, H. Motoyama2
Chlorine-36 (36Cl) is a radioisotope of chlorine with a half-life of 301 kyr. Prior to the Atomic Era, 36Cl
in the environment was largely produced by spallation reactions between cosmic ray particles and target
atoms (i.e. cosmogenic production). However, with the advent of atomic bomb testing, anthropogenic 36Cl
began to be produced by thermal neutron activation of the 35Cl of sea salts. In particular, extensive marine
testing in the 1950s and '60s is thought to have produced a large bomb peak of 36Cl reported from a dozen
ice cores worldwide [1-3].
In this study, we determined 36Cl concentrations in an ice core from the H15 site (69°04'10"S,
40°44'51"E) in Dronning Maud Land, East Antarctica (Fig. 1). The core is 32.01 meters long and isestimated to cover the last 80 to 90 years. The 36Cl was analyzed at the University of Tsukuba Tandem
Accelerator Complex (UTTAC) using a common procedure for ice core 36Cl analysis [4, 5].
The 36Cl concentration varies by two orders of magnitude from 1.0 × 103 to 3.0 × 105 atoms/g (Fig. 2). A
distinct 36Cl peak is found between ~20 and 25 m depth, reflecting a bomb peak of 36Cl at this location. The
maximum of the peak is between 22.5 and 23.4 m depth, corresponding to the late 1950s in the age modelof the core. The nature and cause of the 36Cl variations will be further investigated.

Fig. 2. Depth profile of 36Cl concentrations.

Fig. 1. Location of the core site (H15).

References[1] D. Elmore et al., Nature 300 (1982) 735.
[2] U. Heikkilä et al., Atmos. Chem. Phys. 9 (2009) 4145.
[3] S. Pivot et al., J. Geophys. Res.: Atmospheres 124 (2019) 10973.
[4] K. Sasa et al., Nucl. Instr. Meth. Phys. Res. B 268 (2010) 1193.
[5] K. Kanzawa et al., J. Geophys. Res.: Space Phys. 126 (2021) e2021JA029378.
1Hirosaki University

2National Institute of Polar Research

24

4.
MATERIALS RESEARCH

Simulated density distribution of positrons (yellow) trapped bya Zr vacancy coupled with four oxygen vacancies. Green andred circles correspond to Zr and O atoms, respectively.
−−− Report 4.1

4.1

Impact of cation vacancies on leakage current on TiN/ZrO2/TiN
capacitors studied by positron annihilation

A. Uedono, N. Takahashi, R. Hasunuma, Y. Harashima1, Y. Shigeta, Z. Ni2, H. Matsui2, A. Notake3, A. Kubo3,
T. Moriya4, K. Michishio5, N. Oshima5, S. Ishibashi5High-dielectric constant (k) oxides such as ZrO2 and HfO2 have been extensively studied as an insulator
for DRAM because of their high k value, large bandgap, kinetic stability, their device process compatibility,
etc. [1]. Because these oxides are fast ion conductors, oxygen vacancies (VOs) are easily introduced during
the device process. Such defects are one of the origins causing current leakage and affect the stability of thecrystal phase of high-k films. For high-k based devices, TiN is often used as the top and bottom electrodes.
The capacitor with TiN electrode tends to show large leakage current, which is often attributed to theintroduction of VO due to the scavenging effect of TiN. Positron annihilation is a useful technique to detectvacancy-type defects and open spaces in solid state materials with non-destructive manner [2]. In the present
study, we used monoenergetic positron beams to study the behaviors of vacancy-type defects in
TiN/ZrO2/TiN capacitors [2].
The sample structure used in the present experiments is ZrO2(10 nm)/TiN(5 nm)/SiO2(300 nm)/Si. TiN
and ZrO2 layers were deposited by using physical vapor deposition. SiO2 layers were thermally grown on
Si substrates. A TiN bottom electrode was deposited on SiO2/Si through the reactive sputtering of a pure Ti
target. Then, ZrO2 layers were deposited on the TiN layers. For some samples, a 5-nm thick TiN was
deposited on the sample as a top electrode. Forming gas annealing was performed at 550°C for 5 min in a
N2 atmosphere for the samples with and without the top

10 -5

Vacancies in the ZrO2 layers were probed using thepositron annihilation technique [2]. The Doppler
broadening spectra of the annihilation radiation were
measured by Ge detectors as a function of the incident
positron energy E and characterized using the S
parameter. The lifetime spectra of positrons were alsomeasured. The positron lifetimes in monoclinic ZrO2
were calculated using the quantum materials simulator
code [4].

2Current
density(A/cm
Current density(A/cm -2))

TiN layer.
10 -6

Annealed

TiN/ZrO2 /TiN

10 -7

10 -8
Annealed
with top TiN
10 -9
As-deposited

10-10-2 -1.5-1 -0.5

0

0.5

1

1.5

2

Applied voltage (V)Figure 1 shows current–voltage (J–V) relationshipsof the samples before and after post-deposition
annealing. The bias voltage was applied to the top

Fig. 1. J–V curves for samples before and after
post-deposition annealing. Annealing was donewith and without the top TiN layer.

1Nara Institute of Science and Technology
2Tokyo Electron Technology Solutions Ltd.
3Tokyo Electron Ltd., Sapporo
4Tokyo Electron Ltd., Tokyo
5National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba

25

electrode while the bottom electrode was grounded. The current density was increased by post-deposition
annealing, and this tendency was suppressed by annealing with the top TiN layer.
Figure 2 shows the S values as a function of E for the

0.54
SiO2

samples before and after annealing. The S value at
E=1−1.5 keV can be associated with mainly the

Si

ZrO2

0.52

0.52

for the annealed ZrO2 layers was higher than that for asdeposited one, suggesting the size of vacancies increasedby annealing. This tendency was suppressed by the

S parameterannihilation of positrons in the ZrO2 layer. The S value
0.50

The mean positron lifetimes for the ZrO2 layers forthe as-deposited and annealed ZrO2 were obtained as 300
ps and 400–430 ps, respectively. The lifetimes of
positrons trapped by the vacancy clusters consisting of a
Zr vacancy (VZr) and Vos [VZr(VO)n] were simulated, andthey are obtained as 251, 260, 276, 294, 315, 339 ps for
VZr(VO)n (n=1–6), respectively. From a comparison

ZrO2

0.50

Annealed

0.49

0.48

0.48

Annealed

annealing with the top TiN layer.

0.51

0.46

0.46

Annealed 0.45
with top TiN 0
As-deposited

0.44
0Annealed
with top TiN
As-deposited

0.47

0.5

1

1.5

2

5
10
15
Positron energy (keV)

2.5

3

20

Fig. 2. S parameters as function of incident
positron energy E for samples before and after
post-deposition annealing. Inset shows S–E
curves corresponding to subsurface region.

between the experimentally obtained lifetimes and theones calculated by using the computer simulation, thedefect species in the as-deposited ZrO2 layer was
identified as VZr(VO)4. Figure 3 shows simulated atomic
configurations of the super cell with VZr(VO)4 and (b)Fig. 2. S parameters as function of incident
positron energy E for samples before and after
post-deposition annealing. Inset shows S–E
curves corresponding to subsurface region.

distribution of the positron density around the defect(shown as yellow). For the annealed samples, theobserved

longerpositronlifetimessuggestan

introduction of vacancies larger than VZr-type defects.
The present experiments showed that positronFig. 3. (a) Atomic configuration of super cellwith VZr(VO)4 and (b) distribution of thepositron density around the defect. Green andred circles correspond to Zr and O atoms,
respectively.

annihilation parameters are sensitive to vacancy-type
defects in high-k based capacitors, and the defects that are detectable using positron annihilation are closely
related to leakage current mechanisms. A monoenergetic positron beam, therefore, can provide useful
information for the process parameter adjustment of memory devices.
References[1] J. Robertson and R. M. Wallace, Mat. Sci. Eng. R 88 (2015) 1.
[2] R. Krause-Rehberg and H. S. Leipner, Springer Series in Solid-State Sciences, vol. 127, Springer-Verlag,
Berlin, 1999.
[3] A. Uedono et al., Thin Solid Films 762 (2022) 139557.
[4] S. Ishibashi et al., J. Physics.: Condens. Matter 31 (2019) 475401.

26

4.2

Superparamagnetic relaxation of magnetic nanoparticles studied with
Mössbauer spectroscopy

E. Kita, R. Onodera1, M. Kishimoto, H. Yanagihara
Investigation of nano-particle relaxation behavior is useful for obtaining improved magnetic
hyperthermia performance. Many researchers have analyzed the relaxation characteristics of superparamagnetic nano-particles and their suspensions. AC susceptibility (ACS) measurements are commonlyused to determine the frequency dependent response of magnetization including any relaxation in thefrequency range of up to 1 MHz. Conventional magnetization measurements were performed using avibrating sample magnetometer and ACS testing, covering a wide range of frequencies. Mössbauer
spectroscopy (MS) of 57Fe has a characteristic relaxation time of 10-7 s due to the lifetime of the excitedstate of 57Fe nuclei. MS shows drastic changes
in SP material spectra upon sample temperaturechanges.
We have reported 57Fe MS measurements
performedonacommerciallyavailable

magnetic fluid, Resovist, which is used as aheat mediator in magnetic hyperthermia andmagnetic particle imaging (MPI) and detailed
conditionsofMS

measurements

weredescribed elsewhere [1, 2]. MS study was
performed with varying sample temperatures
between 2.6 and 250 K. Mössbauer spectra
were analyzed with a combination of a few
relaxed sub-spectra originated from the particle
size distribution reported by other researchers[3]. Relaxation times (τBT) were obtained
experimentally from the analysis based on theBlume-Tjon (BT) model [4] and Néel
relaxation time was discussed from these data.
Temperature variation of Mössbauer spectra
for Resovist is shown in Fig. 1. The spectra
obtained at the lowest temperature of 2.6 K
were fitted with Mössbauer parameters ofmaghemite (γ-Fe2O3) and the parameters wellcoincide with those of maghemite [5]. For
Mössbauer spectra at temperatures below 50 K,

Fig. 1. Mössbauer spectra of Resovist recorded attemperatures between 2.6 K and 250 K [2].

the same fitting procedure as that of 2.6 K was
1National Institute of Technology, Ibaraki College27

adopted. At temperatures T ≤ 100 K, MS shows a widely distributed magnetic sextet and small peakbroadening at around zero velocity. Further increasing the temperatures increases the height of the center
peak. The 1st and 6th absorption peaks of the magnetic sextet are unchanged, but the profile changes to an
inward tail distribution of hyperfine field (Hhf). This is often characteristic of Fe atom relaxation.
Table 1. Mössbauer spectral parameters for Resovist between 150 and 250 K. The Mössbauer data wereanalyzed based on the Blume-Tjon two-level model for sub-spectra labeled by MR. Italic characters in thetable show fixed fitting parameters. IS* relative to α-Fe.
Temperature
Sub(K)
spectrum
250

200

150

MR1
MR2
MR3
MR1
MR2
MR3
MR1
MR2
MR3

Hhf
(T)
47.5
43.0
42.0
49.1
45.2
45.0
50.0
46.4
45.0

τBT
(s)

Area ratio(%)

3.8 × 10−8
1.7 × 10−8
6.4 × 10−10
3.0 × 10−8
2.2 × 10−8
6.1 × 10−10
1.9 × 10−8
2.7 × 10−8
7.7 × 10−10

21.1
15.6
63.3
17.2
20.9
61.9
21.7
21.9
56.4

IS*
LW
Rjump
(mm/s) (mm/s)
0.349
0.369
0.343
0.383
0.358
0.396
0.410
0.389
0.409

0.4
0.4
1.22
0.5
0.5
1.31
0.5
0.5
1.61

7.12
7.46
8.89
6.48
7.34
8.79
6.43
7.27
8.81

The Mössbauer spectra recorded at 150, 200, and 250 K, show large center absorption. The fitting was
performed assuming the BT model composed of three sub-spectra with two slow (MR1 and MR2) relaxation
times and another fast relaxation (MR3) time. The subspectra with slow relaxation time (long time) show
an ordinal magnetic sextet with broad linewidth (LW), where LW and jump rates (Rjump) were set to be
identical assuming Fe atoms responsible for MR1 and MR2 belong to the same large particle. In contrast,
the subspectrum with a fast relaxation time (short) shows a widely spread spectrum (Fig 1). Relaxation times(τBT) were deduced from the relation τBT = 1 / (2×10Rjump). The relaxation times thus obtained monotonicallydecrease from 1.9×10-7 to 3×10-8 s for MR1 and MR2, respectively, whereas those for MR3 do notmonotonically change and are scattered between 7.7 × 10-10 − 3 × 10-10 s. By fitting the central part of thespectra to the BT model relaxation sub-spectra, a short τBT and wide LW were obtained for a large Hhf around
40 T, whereas long τBT are represented by a small Hhf of less than 30 T. This may suggest an ambiguity inanalyzing the center part. Fitting parameters are listed in Table 1. The values of isomer shifts (IS) suggestthat Fe atoms are in the 3+ state.
The particle size distribution of Resovist has been reported previously [3]. Bimodal size distributions of
5.5 and 24 nm in mean diameter have been reported and, using K = 104 J/m3, τN at 250 K is estimated to be
1.44 ×10−10 and 1.58 ×10−2 s for 5.5 and 24 nm, respectively.
References[1] E. Kita et al., UTTAC Annual Report 2020, UTTAC-90 (2021) 36.
[2] E. Kita et al., to be published in IEEE Magn. Lett. 14 (2023).
[3] D. Eberbeck et al., Appl. Phys. Lett. 98 (2011) 182502.
[4] M. Blume and J. A. Tjon, Phys. Rev. 165 (1968) 446.
[5] G. M. Da Costa et al., Clays and Clay Minerals 42 (1994) 628.

28

4.3

Magnetic properties of hexagonal CoFe nitrides studied by Mössbauer
spectroscopy

C. Kodaka, M. Kishimoto, T. Sekido, E. Kita, H. Yanagihara
Fe nitrides have been studied as magnetic materials consisting of common elements such as Fe andnitrogen. These Fe–N compounds exhibit various physical properties, such as mechanical strength andmagnetism [1]. The magnetic properties of Fe–N systems, such as Fe16N2, Fe4N and Fe2-3N have beenstudied well. The Fe–N compound with the lowest nitrogen concentration is Fe16N2, which has a body
centered tetragonal (bct) structure. This compound has been extensively studied as a material with highsaturation magnetization (Ms) [1], exceeding bcc-Fe, and high magnetic anisotropy at room temperature [2].
Compounds with nitrogen concentrations higher than Fe16N2 are Fe4N and Fe2-3N. Fe2-3N was realized in an
hcp structure with high mechanical and chemical stabilities; however, for a magnetic material, theirmagnetic properties are not attractive. Fe-based alloy nitrides, for example (FeNi)4N, have been also studied;however, the number of studies is limited because of the difficulty in their fabrication. Recently, an FeNi
nitride, (FeNi)N, was utilized as a precursor of L10-FeNi ordered compounds, which show significantly highuniaxial magnetic anisotropy [3, 4] demonstrating a new application of Fe-based nitrides. Theoretical
calculations have predicted that FeCo alloy nitrides
have a high crystalline magnetic anisotropy [5]. To
investigate magnetic property, such as magnetictransition temperatures and magnetic moments,
Mössbauer spectroscopy(MS) for (FeCo)2-3N was

performed at various temperatures [6, 7].
Three (FeCo)xN compounds with x = 2.25,
2.35, and 2.48 were prepared by nitriding FeCo
alloy particles in an ammonia gas furnace. At first,
FeCo fine hydroxide particles were produced witha co-precipitation technique using Fe and Co
chlorides. A nominal atomic ratio of Fe and Co was
set to 1:1. The particles were spherical, withvolume-weighted

averagediameterofFig. 2. Temperature dependence of thewidth of Mössbauer spectra for x =2.25, 2.35, and 2.48 [6].

approximately 40 nm for FeCo and 70 nm for(FeCo)N. The crystal structures of the FeCo nitrides
were analyzed by XRD [7]. The Rietveld analysis
indicates that (FeCo)2.48N is in an hcp single phase,
although the R factor is not sufficiently small. The
other samples were assigned to be the ε-phase. Notethat neither the γ phase nor any other phaseFig. 1. Temperature dependence of Mössbauer spectrafor (FeCo)2.35N.

appeared in this experiment.

29

MS was performed between room temperature and 3 K. To
achieve low sample temperatures, a closed cycle refrigerator
cryostat was used. The velocity was calibrated using the α-Fe
spectra at room temperature [6, 7].

Figure 1 shows the temperature dependence of the
Mössbauer spectra of the (FeCo)2.35N particles. The spectra

below 50 K appear to be composed of two major magnetic
sextets. Above 70 K, it is not easy to separate into sextets.

Fig. 2. Temperature dependence of thewidth of Mössbauer spectra for x = 2.25,
2.35 and 2.48 [7].

Therefore, the width of the spectrum is defined as the full
width at half maximum in the velocity range. The
widths thus obtained are plotted in Fig. 2. The widths

1.00

for the samples with x = 2.48 and 2.35 decrease at

0.95

approximately 90 K. However, when x = 2.25, the

0.90

hyperfine field was small and decreased rapidly with

0.85

increase in temperature, and the estimated magnetic

and 23 K for x =2.48, 2.35, and 2.25, respectively [7].

The room-temperature MS for (FeCo)xN shows paramagnetic
spectra, and no magnetic subspectra was observed (see
Fig.

3).

It

is

reasonable

that

Relative absorption

magnetic measurements at 103, 95,(FeCo)XN
T = RT

0.80
1.00

transition temperature (TC) was approximately 25 K.
These coincide well with TC determined by thex = 2.25
Sample2magnetization

0.95
0.90
0.85
0.80
1.00
0.98
0.96
0.94

measurements revealed almost paramagnetic states at

0.92

room temperature.

0.88

From the MS and magnetization measurements,
the compounds are ordinally ferromagnetic for x ≥ 2.35.
However, for x = 2.25, more complex magnetic

x = 2.35
Sample3

x = 2.48
Sample1

0.90
0.86
-4

-3

-2

-1

0

1

2

3

4

Velocity (mm/s)

Fig. 3. Mössbauer spectra at room temperature.

ordering is suggested by a magnetization measurement [7]. Griffith’s Phase (GP) may exist, which originatesfrom co-existence of anti-ferromagnetic and ferromagnetic couplings between magnetic atoms.
References[1] J. M. D. Coey, P. A. I. Smith, J. Magn. Magn. Mater. 200 (1999) 405.
[2] E. Kita et al., J. Magn. Magn. Mater. 310 (2007) 2411.
[3] S. Goto et al., Sci. Reports 7 (2017) 13216.
[4] S. Goto et al., ACS Appl. NANO Mater. 2 (2019) 6909.
[5] W. Wang et al., Appl. Phys. Lett. 117 (2020) 122408.
[6] C. Kodaka et al., UTTAC Annual Report 2021, UTTAC-91 (2022) 31.
[7] C. Kodaka et al., IEEE Magn. Lett. 14 (2023) 2500105.

30

4.4

Transmission ERDA of ubiquitous deuterium in H-containing
materials

H. Kudo, H. Naramoto, M. Sataka, S. Ishii, K. Sasa, S. Tomita
Elastic recoil detection analysis of transmission layout (T-ERDA) is useful for quantitative analysis ofhydrogen in solids mainly because of its one-dimensional setup which simpliﬁes the analysis of experimental
data [1]. To investigate further applicability of T-ERDA, we have measured deuterium (D) in H-containing
materials. Notably, the ratio of D to H content (so-called D/H ratio) in a solid sample seems to be a very
similar fraction on the order of 10−4 of hydrogen wherever hydrogen is found on the earth. The D/H ratio
is changeable, for example, it increases if there are natural or artiﬁcial processes at work that concentrateit, for example, distillation (because of higher boiling point of D-water than that of H-water) or electrolysis
of water. The geological and cosmological importance of deuteron analysis has been understood since theearly period of the related research [2].
The experimental setup is similar to that described previously [1]. By using an incident beam of 8 MeV
He2+ from the UTTAC 6MV tandem accelerator, the measurements were carried out under the pressureof 2 × 10−5 Pa. The beam was focused typically to ∼0.1×0.1 mm2 on the samples. The samples used in
the present experiments are thin H-containing ﬁlms of mylar (polyethylene terephthalate, (C10 H8 O4 )n ) of
2.5 µ m thickness, and PPS (polyphenylene sulﬁde, (C6 H4 S)n ) of 1.35 µ m thickness. These ﬁlms were
underlaid with a Ni foil of 20 µ m thickness to prevent the incident He from entering the particle detector.

Yield (counts/channel)

106
105
10

4

10

3

Mylar Recoil H

102

Sample8 MeV He2+

Emittedparticle Detector(ϕ0=3.78°)
Ni foil

3.80 µC
1.56 µC

Recoil D

10
1
3.2

3.6

4.0

4.4 4.8 5.2
Energy (MeV)

5.6

6.0

6.4

Fig. 1. T-ERDA spectra for incidence of 8 MeV He2+ on the mylar ﬁlm of 2.5 µ m thickness, which were
measured for the incident charges of 1.56 and 3.80 µ C. On the horizontal axis, 10.88 keV corresponds to
1 channel width. The inset schematically shows the experimental setup.

Figure 1 shows T-ERDA spectra of the mylar/Ni(20 µ m) sample, measured for the incident He2+ chargesof 1.56 and 3.80 µ C. From the estimate employing the stopping powers by SRIM, the two peaks at 4.16 and5.87 MeV are identiﬁed as recoil H and D from the mylar ﬁlm, respectively. From the T-ERDA spectra, D
and H yields are obtained by counting the areas under the peaks after subtracting the discernible backgroundyield in Fig. 1. The background subtraction has been carried out by assuming the straight baseline connect-31

ing the ends of low- and high-energy tails of the peak, which are clearly recognized in every spectrum
plotted in the linear scale.
Figure 2 shows the ratio of D to H yield plotted against the incident He2+ charge on mylar during
the measurements. The ratio increases with increasing the incident charge because the radiation-induced
loss of H is more than that of D. The ratio of interest in the present case R0 is given by the ratio at zeroincident charge, corresponding to the intersection point of the dashed line and the vertical axis in Fig. 2.
In this manner, we have obtained R0 = (1.05 ± 0.05) × 10−4 and (1.08 ± 0.05) × 10−4 for mylar and PPS,

Ratio of D to H yield (10-4)

respectively.

1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0

8 MeV He2+ on mylar

0

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
Incident He2+ charge (µC)

Fig. 2. Dependence of the ratio of D to H yield on the incident He2+ charge on mylar during the measurements. The dashed line shows the least-square linear ﬁt to the plots. The D/H ratio of interest
R0 = (1.05 ± 0.05) × 10−4 is given at zero incident charge on the dashed line.

The D/H ratio is given by(D/H ratio) = R0 ×

σH
,
σD

(1)

where σH and σD are the recoil cross sections in the laboratory system for H and D, respectively, which are
given by integrating the differential recoil cross sections dσ /dΩ over the solid acceptance angle of the detector. According to the existing experimental data, the most suitable values of σH /σD are (1.48+1.66)/2=1.57
and (1.48+1.56)/2=1.52 for mylar and PPS, respectively. The values of D/H obtained from Eq. (1) are(1.65 ± 0.08) × 10−4 and (1.64 ± 0.08) × 10−4 for mylar and PPS, respectively. These values are only
slightly higher than the Standard Mean Ocean Water (V-SMOW) value of (1.5576 ± 0.0010) × 10−4 [3],indicating ubiquitous deuterium in H-containing materials. The present work demonstrates the wide applicability of T-ERDA to non-destructive analysis of trace D in solids.
References[1] H. Kudo et al., J. Phys.: Condens. Matter 34 (2022) 435902.
[2] I. Friedman, Geochim. Cosmochim. Acta 4 (1953) 89.
[3] J. C. De Wit et al., Geostand Geoanal Res 4 (1980) 33.

32

4.5

Tracking 7Li in all-solid-state batteries using NRA

N. Kishi, S. Kobayashi 1, Y. Sugisawa, R. Shimizu1, T. Hitosugi1, 2, D. Sekiba
All-solid-state Li-ion batteries, which can safely increase the capacity of Li-ion batteries, have attracted
considerable attention. At present, the problem of insufficient conductivity for practical use remains. In thisstudy, in order to elucidate the cause of this problem, we attempted to observe the behavior of 7Li using 7Li(p, α) 4He nuclear reaction analysis (NRA).
NRA was performed using a 1.5 MeV H+ beam from 1MV Tandetron at UTTAC. The detector was
mounted at 150° with respect to the beam direction, and the sample was tilted so that α particles can bedetected at 70° from the surface normal. The sample consists of stacked layers of Li/Li3PO4/ LiCoO2/Au
deposited on a Si3N4 substrate which is a 4.0×7.6 mm2 film with a thickness of 1 µm. The H+ beam wasincident on the substrate side. A power supply for the bias voltage and an ammeter were connected to thesample in vacuum via a feedthrough. After the as-deposited sample was charged by applying the bias voltageof 4.3 V, it was discharged by reducing the bias voltage to 3.0 V. Then, the sample was recharged byincreasing the bias voltage to 4.3 V. In these processes, we observed the behavior of 7Li when the battery
was discharged by comparing the NRA spectra for the 4.3 V charging and the 3.0 V discharging. Similarly,
the behavior of 7Li was observed when the battery was recharged by comparing the NRA spectra for the 3.0
V discharging and the 4.3 V recharging.
Figure 1(a) shows the NRA spectra measured for the sample when it was charged and discharged
afterwards, shown in blue and orange, respectively. Figure 1(b) shows the yield difference, i.e., the “orange− blue” yield, from which we can see the change in the 7Li profile caused by discharging. Indeed, negative
peaks are seen in the energy ranges indicated by a, c, and e which correspond to the layers in the sample
shown in Fig. 1, while positive peaks are seen in the layers b, d, and f. Figure 2(a) shows the NRA spectra
when the sample was discharged and recharged, shown in orange and green, respectively. Figure 2(b) shows
the yield difference, i.e., the “green − orange” yield, from which we can see the change in the 7Li profile
caused by recharging. On the negative electrode side, 7Li decreases in the layers a and a’, while 7Li increases
in the layers b and b’. This implies that 7Li flows from the negative electrode into the solid electrolyte,
regardless of the battery state, probably because of intrinsic migration.
In Fig. 1(b), the amount of increase in 7Li in the layer d seems the same as that of decrease in the layerc, hence we may assume that 7Li in the layer c moves to the layer d. Similarly, we may assume that 7Li inthe layer e moves to the layer f. According to the above assumption, 7Li diffuses from the electrolyte to thepositive electrode like billiard balls when the sample is discharged. In Fig. 2(b), 7Li moves from the layer eto the layer d, and the layer d to the layer c, as if reproducing the profile seen in Fig. 1(b), thus we consider
that 7Li moves from the layer e to d to c. On the other hand, 7Li in the layer f seems to move to the layer c,which does not seem to reproduce the profile seen in Fig. 1(b). To investigate the cause of this result, we
will use a target with a deposited 6Li-enriched layer in future.
1Tokyo Institute of Technology
2The University of Tokyo

33

Fig. 1. (a) NRA spectra measured for the sample

Fig. 2. (a) NRA spectra measured for the sample

when it was charged and discharged afterwards,

when it was discharged and recharged afterwards,

shown in blue and orange, respectively. (b) The

shown in orange and green, respectively. (b) The

yield difference between the two spectra.

yield difference between the two spectra.

Reference[1] N. Kishi et al., UTTAC Annual Report 2021, UTTAC-91 (2022) 34.

34

4.6

Electrochemical route to quickly insulate photo-metalized YOxHy(111)epitaxial thin films

Y. Komatsu 1, Y. Sugisawa, N. Kishi, T. Hitosugi 2, D. Sekiba, R. Shimizu1
Yttrium

oxyhydrides(YOxHy)have

attracted

considerable attention due to their photochromic
properties for optoelectronics applications such as smart
windows and photo sensors [1]. Recently, our groupreported

repeatable

photo-induced

metal-insulatortransition in YOxHy (111) epitaxial thin films [2]. This
photo-metalized state is retained within a few days (>105

Fig. 1. Schematic illustration of photo-inducedsec) at room temperature (memory effect). To accelerate metallization in YOxHy (111) epitaxial thin films [2].
the recovery to the original transparent and insulatingstate within a few hours (~103 sec), the annealing is necessary at around 100°C. The mechanism of themetallization/insulation processes is correlated with the internal migration of hydrogen ions and/or atoms.
Electrochemical methods provide a route to promote internal hydrogen migration. For example, theinsertion/desertion of interstitial H+ causes metal/insulator switching in WO3 and VO2 (electrochromism)
within ten seconds [3]. Accordingly, it is expected that a similarly quick recovery to the original transparent
and insulating states can be electrochemically performed in YOxHy.
Here, we investigated the electrochemical responses of photo-metalized YOxHy. We found the potential
application of 0.0 V (vs. Ag/AgCl) (+0.57 V vs. reversible hydrogen electrode (RHE)) in 0.1 M NaClsolution insulates the photo-metalized YOxHy within ~5 sec. This speed is 4 orders of magnitude quicker
than the conventional thermal relaxation processes (>105 sec). Surprisingly, the insulated film can be
metalized again by UV laser illumination, and this photo-metallization and electrochemical insulation canbe performed ten times at least. Using ion beam analyses such as nuclear reaction analysis (NRA), elastic
recoil detection analysis (ERDA), and Rutherford backscattering spectroscopy, we found that photogenerated H is deserted from the film during the electrochemical insulating processes.
YOxHy (111) epitaxial thin films were deposited on yttria-stabilized zirconia (YSZ) (111) and CaF2 (111)substrates using reactive magnetron sputtering. YHy precursor films were deposited with a mixture of argon
and hydrogen gas introduced into the deposition chamber, and the substrate temperature was set to 150°C.
After the deposition, the as-grown film was exposed at room temperature to oxygen gas at 1 atm to fully
oxidize the films. To characterize H contents in films, we performed secondary ion mass spectrometry(SIMS) and ion beam analyses. ERDA measurements were performed at UTTAC.
Figure 2 shows the results of electrochemical processes on photo-metalized YOxHy. While only the H2evolution reaction occurs under the potential application of −4 V (vs. Ag/AgCl), we observed oxidation
current at ~ −0.6 V (vs. Ag/AgCl), leading to the insulation of the thin films (Fig. 2(a)).
1Tokyo Institute of Technology
2The University of Tokyo

35

This process wasprocesses

arerepeatedly

operated. Figure 2(b) shows the electricalresistancechangemetallization

(UV

in

the

steps

illumination)ofandinsulation (+0.0 V application in NaClsolution). Note that the potential of +0.0 V

-2.0

0V

-4 V

clippedPt-4.0

Ag/AgCl-6.0

NaCl aq.

soaked

1.2

-3

0.4

YOxHy/YSZ(111)

1012

0
0

0

1010

4
2

0

-2
-1
Ewe (V) vs. Ag/AgCl(c)

6
YOxHy/
Nb:TiO2/glass
Nb:TiO2/glass

0.8

UV-illuminated YOxHy-4

Resistance (Ω)

These

(b)

0

Current density(mA cm-2)

relaxation.

Current density(mA cm-2)

quicker than the conventional thermal(a)Normalized charge(% per Y atom)completed within 10 sec (Fig. 2(b)), 4 orders

2 4 6 8Time (sec)As-grown+0.0 V application
UV illumination

108
106
104
102
1

2

3

4

5

6

7

8

9

10

The number of UV illumination

vs. Ag/AgCl corresponds to +0.57 V (vs. Fig. 2. (a) Cyclic voltammogram at the potential of −4 V to +0 V
RHE), which does not exceed the ideal O2 (vs. Ag/AgCl). (b): Temporal change of current density (red) andnormalized charge per Y atom (blue) at +0.0 V (vs. Ag/AgCl). (c):evolution potential (+1.23 V vs. RHE). Resistance change in the repeated steps of UV illumination andThus, we achieved repeatable resistance electrochemical insulation.
switching 10 times at least.
To

understand

the

(a)

(c)

(b)

electrochemical

insulation mechanism, we evaluated the H
content in the thin films. Figure 3(a) shows
the depth profiles obtained by SIMS after the
potential application of +0.0 V vs. Ag/AgCl,
indicating that the H content in the films

Fig. 3. Depth profiles obtained by SIMS (a: as-grown, b: 1st +0.0

gradually decreases. Namely, photo-induced V vs. Ag/AgCl application, c: 5th +0.0 V vs. Ag/AgCl
H+, which generates electron carriers in the application). H ions decreased in (c).

thin films, is released into the solution.

(b)

(a)

Accordingly, the desertion of H+ carrier
electrons leads to transparent and insulatingstates. Deserted H atoms are again inserted
into the YOxHy thin films by the negative
potential

application of−5.0 V (vs.

Ag/AgCl). Figure 4(a) shows the result of Fig. 4. (a) Resistance switching only by electrochemical

processes. (b) ERDA results of YOxHyDδ after negative potential

resistance change, indicating metallization application of −5.0 V vs. Ag/AgCl treated in 0.1 M NaCl in D2O
also electrochemically occurs. Using ERDA, solution. D signal from the D2O solution is observed.

Fig. 4(b) clarifies the existence of D in the films after the electrochemical treatment. These results indicatethat the insertion/desertion of H/D plays a critical role in the drastic change in the optical and electricalproperties of YOxHy.
References[1] T. Mongstad et al., Sol. Energy Mater. Sol. Cells 95 (2011) 3596.
[2] Y. Komatsu et al., Chem. Mater. 34 (2022) 3616.
[3] J. Y. Zheng et al., Nanoscale 15 (2023) 63.

36

4.7

Study for hydrogen content for UCN storage

K. Mishima 1, S. Kawasaki1, N. Kishi, D. Sekiba, K. Yamamoto
Ultracold neutrons (UCNs) are extremely slow neutrons with energies below ~300 neV and totallyreflected on material surfaces due to their long wavelength. UCNs are very interesting probes for
fundamental physics because they can be stored in a vessel and manipulated. The TRIUMF Ultra-Cold
Advanced Neutron (TUCAN) collaboration aims at a precision neutron electric dipole moment (nEDM)
measurement with an uncertainty of 10−27 e·cm, which is an order of magnitude better than the current
nEDM upper limit and enables us to test new physics [1].
For UCN transport, Nickel-phosphorus (NiP) plating, which is inexpensive and easy to process, is often
used. UCN is totally reflective on the surface, but a very little, about 10-4−10-5 per reflection, is absorbed. It
is known that the absorption has a large variation depending on the fabrication process and the surface
conditions [2]. This is suspected to be caused by impurities on the NiP surface, especially hydrogen, which
has a large incoherent scattering cross section and causes the disappearance of UCN by up-scattering. For
that investigation, we measured some NiP plated samples with Elastic Recoil Detection Analysis (ERDA)
to determine the hydrogen concentration on NiP surfaces. The phosphorous concentration in NiP is also
important to determine the reflection critical potential at the surface. This was determined by Rutherford
Backscattering Spectrometry (RBS). The experimental setup is shown in Fig. 1. The sample was irradiatedwith 2.5 MeV 4He2+ incident from the left in Fig. 1, and backscattered He for RBS and recoil H for ERDA
were measured using the backward and forward detectors(SSD), respectively.
Four NiP samples were measured in this study. Two of
the samples were cut from the φ90 mm cylindrical UCN
guide tubes actually used in the TUCAN experiment andplated with NiP on the inner surface; the NiP roughness
was measured at the commonly used Ra = 50 nm and at Ra= 800 nm, which is before polishing. The other two wereNiP plated on flat Al surfaces and each polished to reachRa = 1 nm and 2 nm.
The RBS spectra are shown in Fig. 2 (left). The peakFig. 1. The RBS and ERDA setup. The He ion
beam is incident from the left.

due to P is observed at 350 channel. For the UCN guide sample (50-nm Ra), the P content is estimated as 20
atom%. This corresponds to 12 weight% and is consistent with the designed value [2]. The samples on flatAls (1- and 2-nm Ra) have relatively low P content.
The ERDA spectra show hydrogen content from the surface to the effective depth of 100 nm (Fig. 2
right). Based on the yield of Ni in the RBS spectrum, the hydrogen contents were estimated to be 15−16
atom% for the UCN guide samples (50- and 800-nm Ra) and 2−3 atom% for the flat samples. These results

1High Energy Accelerator Research Organization (KEK)37

are considered to be due to the moisture attached to the surface. At depths greater than 100 nm, the H
contents were 1.2% for 800-nm Ra, and 0.6% for the others, indicating that the hydrogen contamination
except the surface could be kept small.

Fig. 2. The RBS (left) and ERDA (right) spectra for the NiP samples with different roughness.

References[1] R. Matsumiya et al., Proc. 24th International Spin Symposium (SPIN2021), JPS Conf. Proc. 37 (2022)
020701.
[2] H. Akatsuka et al., Nucl. Instr. Meth. Phys. Res. A 1049 (2023) 168106.

38

5.
ION-BEAM IRRADIATION EFFECT

Sunlight

Outgas+125°CGas adsorption−150°CSpace environment experienced by a satellite (adapted froma material in the web page of NDK, using a free-use
illustration).
−−− Report 5.2

5.1

Evaluation of LoRaTM transceiver and microprocessor toward space use

T. Kameda, Y. Kurihara, H. Yoshikado
When semiconductor components are used in space, the effects of space radiation must be considered
for stable operation [1]. In particular, heavy ions in cosmic rays can cause SEE (Single Event Effect), which
can lead to temporary malfunction (soft error) or permanent failure (hard error) of semiconductors andinterfere with spacecraft operations. Therefore, a detailed investigation is required in advance [2].
We focused on LoRaTM modulation for space applications because of its high interference tolerance oververy long distances and low current consumption. From this perspective, among the commercially available
products, Murata's CMWX1ZZABZ (SX1276) the LoRaTM transceiver on the Arduino MKRWAN 1310
board has been chosen, and its feasibility of the space applications was investigated.
In addition, since the microcontroller device is required for data handling with the transceiver, radiation
exposure tests were conducted to verify the feasibility of use in space for the STM32F401 that is an Armbased microcontroller mounted on the Nucleo-32 development board, and the CXD5602 that is a chip
mounted on the Sony board computer, SPRESENSETM.
The test samples of de-capped STM32F401, CMWX1ZZABZ, and CXD5602 were irradiated with 48
MeV F7+ and 48 MeV Cl7+ from the 6MV tandem accelerator at UTTAC. The arrangement of each device isshown in Fig. 1. The number 0, 1, and2 in Fig. 1 show STM32F401 on the
Nucleo-32

development

CMWX1ZZABZ

on

the

board,
ArduinoMKRWAN 1310, and CXD5602 on the
SPRESENSE,

respectively.

Weobserved the incidence of (i) bit flips
associated

with

soft

errorsformicroprocessors, (ii) the data changes
between transmission and reception
and the mode changes for LoRaTM
transceivers, and (iii) the increase in

Fig. 1. Specimen configuration for the irradiation tests.

power consumption associated withhard errors to determine the occurrence of SEU (Single Event Upset) and SEL (Single Event Latch-up)
during irradiation with changing the number of particles.
The bit flips of the memory in the microprocessors are monitored as follows: the 96 KB SRAM of the
STM32F401 and the 1.5 MB SRAM of the CXD5602 were filled with the char type "U" (0x55, 0b01010101)
in the unused memory area, and checked every 10000 ms (±1%) to monitor SEL, and electric current was
logged every 500 ms.
Table 1 summarizes the experimental results: for the first irradiation of STM32F401 (when the numberof Cl was 1463 particles/sec), no SEE was observed based on the electric current. However, during the next

39

irradiation of 2138 particles/sec, about 500~700mA electric current was observed, whereas the usual current
is 60~70 mA. After cutting off the irradiation by the shutter and restarted the semiconductors, normal current
values were observed, and once the shutter was raised, the overcurrent was observed again. We checked thelog of the contents of SRAM memory with reducing the number of particles, we could not confirm theoccurrence of SEU as long as the system operated even when the current value was increased.
In CMWX1ZZABZ, a SEL of about 30 mA was generated each time after the second irradiation. Afterthe second irradiation, the device switched to the reception mode from the initial transmission mode, also
switched to the transmission mode from the initial reception mode. From these observations alone, it is notclear at this point whether this is caused by SEU or not. In order to clarify the cause of this phenomena, it
is necessary to monitor this behavior by periodically dumping the registers of this module, for example.
No SEL was observed for CXD5602 at any particle number. The SEU has not been tested because of
unexpected serial communication device trouble other than SPRESENSE.
In conclusion, STM32F401 cannot withstand cosmic radiation at the level of LET 17.3 MeV/(mg/cm2),and the lower limit of the radiation resistance is unknown. The CMWX1ZZABZ showed SELs and operation
problems such as mode switching, hence further investigation is necessary for quantitative evaluation
toward space use. The CXD5602 seems to have sufficient radiation tolerance since no SELs were observed.
We would like to verify SEU in the next test by resolving equipment problems.
Table 1. Irradiation results.

References[1] T. Kameda et al., Aerospace 9(6) (2022) 280.
[2] Y. Chiba et al., JAEA-Review 2013-057 (2013) 73.

40

5.2

Evaluation of COTS electronic devices for space applications

H. Kukita 1, E. Miyazaki 2, T. Shiobara1, T. Kimura1
The Japan Aerospace Exploration Agency (JAXA) and Nihon Dempa Kogyo Co., Ltd. (NDK) developed
a compact, power-saving, Twin-QCM outgas sensor system for general-industry application. This system
was commercialized by NDK for evaluation of materials used in space [1, 2]. We are now jointly researchingand developing a system suitable for embedded use, which is also expected to be used in the spaceenvironment. In order to judge whether COTS (Commercial Off-The-Shelf) grade electronic components
selected in the development process can be used for space applications, we evaluated the performance ofradiation-resistance of BBM (Bread Board Model), using the 6MV tandem accelerator at UTTAC. A COTS
grade SoC-FPGA (System on a Chip Field-Programmable Gate Array) mounted on a circuit board wasirradiated with proton and heavy ion (oxygen) beams to test the single event effect.
Test results (February 2023)
Beam irradiation tests with 12 MeV H+ and 54 MeV O8+ were conducted.
(1) Proton (12 MeV H+) irradiation test results
Part type

Components

Material

Thickness
[µm]

-

-

Au

0.2

11.99

SoC-FPGA

Initialmaterial for
derangement
packagepassivation
wiring layer
wiring layer
sensitive layer
substrate

Energy after
passing matter
[MeV]
12.00

Epoxy
Kapton
Al
Cu
Si
Si

-

Range
in Si
[µm]
-

-

-

LET in Si[MeV/(mg/cm2)]

The package and passivation material were removed
by decap for irradiation test.
*
*
*
*
*
11.76
0.031
941.16****

Result

SEL:none
SEU:none*: non-disclosure(2) Heavy ion (54 MeV O8+) irradiation test results
Part type

Components

Material

Thickness
[µm]

-

-

Au

0.2

53.25

SoC-FPGA

Initialmaterial for
derangement
packagepassivation
wiring layer
wiring layer
sensitive layer
substrate

Energy after
passing
matter [MeV]
54.00

Epoxy
Kapton
Al
Cu
Si
Si

-

Range
in Si
[µm]
-

-

-

LET in Si[MeV/(mg/cm2)]

The package and passivation material were removed
by decap for irradiation test.
*
*
*
*
*
17.23
6.392
11.91
*
0.00
0.000
0.00

Result

SEL:noneSEU:
occurrence*: non-disclosure

1NIHON DEMPA KOGYO CO., LTD.
2Japan Aerospace Exploration Agency

41

In the irradiation tests with H+ and O8+, SEL (Single Event Latch-up) did not occur. On the other hand,in the O8+ irradiation of SoC-FPGA , which was equipped with an ECC (Error-Correcting Code) function,
SEU (Single Event Upset) phenomenon occurred and resulted in a system freeze despite the enabled ECC
function.
We concluded that implementation of ECC function is not enough for SoC-FPGA that is used in spaceenvironment, and radiation countermeasures such as implementation of SEM (Soft Error mitigation)function and TMR (Triple Modular Redundancy) are necessary. In the future, a radiation countermeasurefunction will be installed and its effectiveness will be investigated. Such tests will be conducted with varying
irradiation conditions such as ion energies to evaluate error rates on the actual operation orbit, thereby afinal judgment will be made.
References[1] Outgas Analysis System (NDK)
https://www.ndk.com/en/products/outgas/[2] Y. Tsuchiya et al., IEEE Sensors Journal 21 (2021) 10530.
https://ieeexplore.ieee.org/document/9351992

42

5.3

Observation of nonreciprocal critical current in YBa2Cu3O7 films
irradiated with 75-MeV Au ions directed off-normal to the film surface

H. Matsui 1, G. Nishijima 2, A. Matsumoto2, I. Yamaguchi1, T. Manabe1, M. Sohma1
Asymmetry of critical current (Ic) in a superconductor with respect to the current direction(forward/backward) is called superconducting diode effect (SDE), and has attracted great interest for its
potential application to superconducting electronics. To date, various SDEs have been reported for both lowand high-temperature superconductors (HTSCs) [1, 2]. However, only a few examples possess both of thefollowing technological benefits that can be applied to produce a practical SDE: (1) HTSC and (2) out-ofplane magnetic fields (parallel to the c-axis in HTSCs, B//c). Two advantages of the latter benefit are easyalignment between a superconducting film and magnetic-fields and reduction of the device size including
magnet(s).
In this work [3], we observed an SDE in YBCO films irradiated with 75-MeV-Au ions at 30°-off normal
to the film surface. Up to 3% asymmetry of dc-transport Ic between opposite current directions was detected
remarkably in B//c. The Ic asymmetry was observed only below 0.3 T, suggesting that it is a low-magneticfield phenomenon. Moreover, the Ic asymmetry abruptly changed sign when the magnetic-field angle (θ)
was rotated across the ion-incident angle (φi), clearly indicating a central role of the irradiation defects inthe anomalous current property. Our results suggest that introduction of tilted 1D defects produces anunconventional SDE in YBCO films that functions in industrially advantageous B//c.
We deposited 1.0-µm-thick YBCO epitaxial films (Tc = 90.8 K) on CeO2-buffered SrTiO3 substrates byfluorine-free metal-organic deposition. The 75-MeV Au-ion irradiation was performed in a vacuum of
1×10−6 Torr at room temperature with a 6-MV tandem accelerator at University of Tsukuba. The specimens
were fixed to a sample holder by electrically conductive adhesive tape to avoid electric charging by theirradiation. The incident angle of ions was set 30°-off normal to the film surface. Irradiation dose was set to
3×1010 cm−2 by controlling beam current and exposure time. In-magnetic-field Ic was measured at 77 K
using a four-probe transport method in a temperature-controlled helium continuous-flow cryostat in the
maximum Lorentz-force configuration. A 2 mm × 0.05 mm bridge normal to the tilting plane of the ion
irradiation was fabricated by laser abrasion through a stencil mask.
Figure 1 shows a schematic that explains the geometry of ion irradiation and dc-transport measurements.
The two angle parameters θ and φi are defined. Figure 2 shows the current-voltage characteristics of a 75MeV-Au-irradiated YBCO film measured at 77 K and θ = 0° for different magnitudes of magnetic field (B).
We observe a noticeable difference in Ic between the opposite current directions, i.e., larger Ic for positive
current (black) than negative current (red, asterisk) in 0.1, 0.2, and 0.3 T. But this difference suddenly
disappears at 0.4 T. By measuring the current-voltage characteristics at various θ (not shown), we observedthat the sign of this Ic asymmetry, i.e., the polarity of SDE, was reversed by rotating θ across θ = φi. As wediscussed in Ref. 3, these SDE properties are explained by nonreciprocal dynamic pinning of vortices
1National Institute of Advanced Industrial Science and Technology (AIST)
2National Institute for Materials Science (NIMS)

43

achieved in the coexistence of tilted 1D vortex-pinning-centers and significantly different vortex-pinningstrengths between the film surface and film-substrate interface.

Fig. 1. Schematic explaining the geometry of ion irradiation and in-magnetic-field dc-transport measurements.

Fig. 2. Magnetic-field dependence of the current–voltage characteristics in a YBCO film irradiated with 75 MeV
Au ions directed 30-off normal to the film surface. The measurements were performed at 77 K and B//c (θ = 0°)
with positive current (black) and negative current (red, asterisk).

References[1] A. Daido et al., Phys. Rev. Lett. 128 (2022) 037001.
[2] S. A. Harrington et al., Appl. Phys. Lett. 95 (2009) 022518.
[3] H. Matsui et al., Appl. Phys. Lett. 122 (2023) 172601.

44

5.4

Study on mutagenesis with 15N-resonant nuclear reaction and radiation
effects

I. Suzuki, T. Yang, T. Ikeda, S. Kubo, Y. Maeda, K. Sasa, S. Ishii, K. Tomita 1, H. Matsui, Y. Iwata1
Ionizing radiation is a typical exogenous source of the direct topological lesion of DNA molecules aswell as the indirect influence arising from endogenous sources such as reactive oxygen species. Doublestrand breaks or clustered DNA lesions have been one of the leading subjects of mutagenesis or
carcinomatous genomic variation [1, 2]. An enormous number of studies on the DNA damage haveelucidated the damage sensing, repairing, and tolerance pathways necessary for cells to survive [3]. However,since the direct topological DNA lesion induced by ionizing radiation has been commonly addressed as asingle event independent of the response biofunction, it has been established to formularize the radiation
effects of any kind of ionizing radiations with linear energy transfer, LET. In the report, the authors present
DNA damages induced by the proton-capture nuclear reaction 15N(1H, α1γ)12C of the stable nitrogen isotope
15

N nuclei, which are inherent in DNA [4, 5]. The 15N-DNA suffers both the radiation effects of the incident

proton beam and the nuclear reaction products of 12C6+ and 4He2+ ions. Since both radiation effects
spatiotemporally take place in a microscopically finite space of the DNA molecules, a possibility of
nonlinearity can be expected in DNA damage.
Figure 1 shows pUC4-KIXX plasmid DNA possessing two kinds of resistance genes to the anti-biotics
of kanamycin (R-kanamycin) and ampicillin (R-ampicillin). The genetic structure of the R-kanamycin andR-ampicillin resistance genes consists of 318 and 512 adenine-thymine base pairs (A-T bps) and the 477
and 454 guanine-cytosine base pairs (G-C bps), respectively. The Escherichia coli cells transformed with

Fig. 1. Genetic structure of the 15N labeled pUC4KIXX plasmid possessing resistance genes of Rkanamycin and R-ampicillin to the anti-biotics. The
isotope abundance of 15N varied from the naturalabundance ratio of 0.364 % to the maximum ratio
higher than 98%.

Fig. 2. Colony images of Escherichia coli transformed with theproton-irradiated 15N-pUC4-KIXX plasmids, which suffered
the radiation effects of the 15N(1H, α1γ)12C nuclear reaction
depending on the isotope abundance of 15N.

1National Institute of Advanced Industrial Science and Technology (AIST).

45

the pUC4-KIXX plasmid can be resistant to the anti-biotics of kanamycin and ampicillin.
15

N-pUC4-KIXX plasmids were prepared by substitution of constituent nitrogen atoms with the stable

isotope of 15N with the isotope abundance ratios [15N] / [15N + 14N] from the natural abundance ratio of
0.364% to the maximum ratio higher than 98%. Proton beam irradiation to the 15N-pUC4-KIXX plasmids
was performed with the 1MV Tandetron accelerator at UTTAC. The proton energy was set at the resonanceenergy of the 15N(1H, α1γ)12C nuclear reaction, and each plasmid target was irradiated with the proton doseof 0.2 μC. The E. coli cells transformed with the proton-irradiated 15N-pUC4-KIXX plasmids grew in thetwo kinds of culture media, including kanamycin or ampicillin. If the resistance genes of R-kanamycin orR-ampicillin in the E. coli cells have not been damaged by proton beam irradiation, the E. coli cells can livein the culture media including anti-biotics of kanamycin or ampicillin to form a colony. The number ofcolonies obtained in both the culture media strongly depends on the isotope abundance ratios of 15N as
shown in Fig. 2. The 15N-pUC4-KIXX plasmids with the natural abundance ratios of 15N suffered theradiation effects of a proton beam dominantly. As the isotope abundance ratio of 15N increases, the radiation
effects of the 15N(1H, α1γ)12C nuclear reaction, which follows proton beam irradiation, become evident. In
the higher abundance ratios of 15N than 75%, the number of colonies reduces to less than one-thousandth of
the number of colonies in the natural abundance ratio.
In summary, the authors demonstrate in the report that the radiation effect of the 15N(1H, α1γ)12C nuclear
reaction is an efficacious mutagen to mutate DNA which contains the stable isotope of 15N with a specificisotope abundance varied from the natural abundance ratio of 0.364 % to the maximum ratio higher than98%. The radiation effects of the 15N(1H, α1γ)12C nuclear reaction may also give rise to genomic damage ofmalignant tumor. The present results elucidate a possibility that disparity in the isotope abundance ratio of15

N between normal cells and cancerous tumor cells leads to a new proton therapy to target the genomes ofmalignant tumor.
References[1] B. Pilzecker, et al., Nucleic Acids Research 47 (2019) 7163.
[2] I. Suzuki, et al., UTTAC Annual Report 2021, UTTAC-91 (2022) 50.
[3] L. M. Korsholm, et al., Nucleic Acids Research 48 (2020) 9449.
[4] I. Suzuki, et al., UTTAC Annual Report 2020, UTTAC-90 (2021) 44.
[5] Y. Iwata et al., European Advanced Materials Congress (EAMC2019), Stockholm during 11–14 August(2019), Invited paper.

46

6.
TECHNICAL REPORTTechnology exchange between KEK and University ofTsukuba. The engineers of KEK are visiting the tandem
accelerator facility of UTTAC.

6.1

Development of the terminal vacuum gauge system

Y. Yamato, T. Yoshida, S. Ishii
NEC's 6MV tandem accelerator (18SDH-2) isoriginally equipped with a thermocouple tomonitor the internal low vacuum of the highvoltage terminal. However, monitor of highvacuum is needed not only to accelerate polarized
beams, but also to confirm the fully closed state of
the needle valve of the gas stripper. Hence, a new
vacuum gauge system has been developed andinstalled in the high-voltage terminal of the 6MV
tandem accelerator.
We started with several offline tests using a test
chamber which reproduces the vacuum and highpressure environment of the accelerator tank,shown in Fig. 1. A Mirapro Cold Cathode Tough
Gauge (CCTG200C) attached to the chamberwithstood mechanically at least 5 atmospheres

Fig. 1. Offline tests of the vacuum gauge.

outside the vacuum gauge. To operate this gauge,a new nipple with feedthroughs into the accelerator tank was designed and fabricated. The feedthroughs
consist of BNC hermetically sealed connectors for power supply and LAN (RJ45) hermetically sealed
connectors for communication. As a result, the vacuum gauge operated without problems in the environmentof 6×10−6 Torr inside and 5.5 kg/cm2 of N2 gas outside the vacuum gauge.
After the successful offline tests, thedevice was attached to the high-voltage
terminal of the 18SDH-2, shown in Fig.
2. The communication of CCTG200C
by RS-232C can be converted to LAN
using a serial device server (NPort). To
use LAN at the high-voltage terminal,
two plastic optical fibers (POF) werestretched from the high-voltage terminal
to the grounded accelerator tank along
the beam direction. The fibers were
Fig. 2. Inside the shielded terminal box with the connected new
vacuum gauge (indicated by the yellow arrow).

47

fixed to all columns with newly
designed original fixtures, see Fig. 3.

A software was developed to remotely
monitor CCTG200C-NPort communications
using Experimental Physics and Industrial
Control

System(EPICS)

Asyn

andStreamDevice. The user interface employs
Control System Studio (CSS) for real-time
display and trend graphs, shown in Fig. 4.
It should be noted that troubles occurredwith the new terminal vacuum gauge system
during conditioning of the accelerator. Whenthe tank sparked, CCTG200C, NPort, LANFig. 3. Work of fixing POF to the column, using the newly
designed fixtures.

POF converter, and other devices froze
frequently. To reset the system, it wasnecessary to turn off the terminal generator(RS), wait a few tens of seconds, and turn itback on, or unplug the power supply to the
LAN-POF converter outside the tank.
Table 1 shows the terminal vacuum gauge
data when Ar stripper gas was supplied. Since
CCTG200C is not applicable above 4×10−3
Torr, it is better to use the original
thermocouple for further supply of the Ar gas.
Also, with the new terminal vacuum gauge, it
was found for the first time that the terminal
vacuum improves from 1×10−5 to 4×10−7 Torrwhen the turbomolecular pump at theFig. 4. Real-time display for the terminal vacuum gauge.

terminal is stopped.

Table 1. Ar gas valve rotation and terminal vacuum value data.

Terminal GS PR GS DC IGC 02-2 IGC 03-1
(Torr) (mpsi) (Trn) PR(Torr) PR(Torr)
9.6E-05
7.0
4.0
8.7E-08 5.9E-08
1.4E-04
7.1
4.5
8.6E-08 5.9E-08
2.8E-04
7.2
4.8
8.6E-08 6.0E-08
7.7E-04
7.6
5.0
9.4E-08 6.5E-08
1.3E-03
8.0
5.1
1.0E-07 7.1E-08
1.8E-03
8.5
5.2
1.1E-07 7.7E-08
4.1E-03
8.9
5.3
1.2E-07 8.6E-08
4.9E-03
9.9
5.4
1.3E-07 9.6E-08
5.6E-03
13.6
5.5
1.5E-07 1.1E-07

48

6.2

VR-techniques for electrostatic tandem accelerator

T. Yoshida, Y. Yamato, K. Sasa, K. Hirota1, M. Furusaka1
University of Tsukuba Tandem Accelerator Complex (UTTAC) owns the 6MV Pelletron tandem
accelerator and the 1MV Tandetron accelerator, which are used in research and educational activities. The
purpose of developing Virtual Reality (VR) exhibition is to use it for undergraduate student’s experimental
practice in accelerator science, high school student’s facility tours, and education for human resource
development. The present work was supported by International and Inter-institution Network for Accelerator
Science to Next Generation (IINAS-NX).
The tank of the 6MV Pelletron tandem accelerator is always filled with insulating SF6 gas at 5
atmospheres to prevent electrical discharge and, for this reason, the tank is opened only once a year for
regular maintenance. Almost all visitors cannot have a chance to look inside the accelerator tank during thetour, but instead, they can see the inside using VR goggles. Using VR goggles to see 360-degree photo inside
the accelerator tank, visitors can look around inside the tank as if they were actually in the tank. Throughsuch experience, we hope to get undergraduate and high school students interested in accelerators. As an
example of actual use of VR, an educational accelerator KETA at KEK is presented in VR which is used foropen to the public [1]. The Hiroshima Synchrotron Radiation Center (HiSOR) has a web page showing thefacilities in VR [2]. We hope to release many types of accelerator VR for public, cooperating with otherfacilities.
For the development environment for VR, we have chosen Unity, the game engine developed andprovided from Unity Technologies [3]. Unity allows to build data for many platforms such as Android, iOS,
Windows, and webGL. We made the VR data by Unity and, after these data were built for the Andoroid
format, the data were sent to the Oculus Quest 2 of the VR goggles to see the accelerators in the VR.
The VR created was divided into two parts: the
6MV Pelletron tandem accelerator and the 1MV
Tandetron accelerator. The former VR was set up sothat a total of five contents could be switched bypressing a button on the controller attached to the
VR goggles: two 360-degree photos of the inside of
the tank, two overhead shots of the entire

Fig. 1. VR view inside the tank of the 6MV Pelletron
accelerator room, and the Computer Graphics (CG) tandem accelerator.
of the 6MV Pelletron tandem accelerator. The latter VR was set up for a total of two contents; overhead shotof the entire accelerator room, and the CG of the 1MV Tandetron accelerator. It can be switched by pressing
a different button on the controller. For the 1MV Tandetron accelerator, only the photo of the accelerator
room can be viewed since the tank normally remains closed.
The front view inside the tank of the 6MV Pelletron tandem accelerator is shown in Fig. 1. Using VR

1High Energy Accelerator Research Organization (KEK)49

goggles, one can see the 360-degree view inside the accelerator tank, including the wall behind and theladder at the feet. By tilting the controller stick, one can get closer to the photo and observe the pellet chainthat carries the electric charge and the accelerator tube at the center of the tank.
Not only the 360-degree photo, but also the CG of the accelerator was created by importing CAD data
(Figs. 2 and 3). The position of the view changes as one walks around, allowing to look into the inside ofFig. 3. CG image of the 1MV TandetronFig. 2. CG image of the 6MV Pelletron
accelerator.
tandem accelerator.
the accelerator. As shown in Fig. 4, the inside of the accelerator tube can also be viewed to follow the passing

beam. The beam is shown schematically by a spherical object
that pops out sequentially.
We have five VR goggles now for five people at the sametime. In FY2022, the VR goggles were used by a total of 258
visitors (217 high school students, 25 university students, and 16
participants in the technical workshop). In Fig. 5, the visitorswith the VR goggles in front of the accelerator tank are looking
at the VR view with amazement. However, it is difficult for themFig. 4. Image of the beam passing
through the accelerator tube.

to communicate with the guide who explains the VR view, sinceeach of them is looking at a different view at the same time. In
the future, we need to develop such a function that can display
explanations about the tandem accelerator, thereby the visitors
understand the mechanism of the acceleration of ion beams.
Furthermore, the VR view with explanations will be used as ateaching material for students. To compensate the limited
number of VR goggles, we are considering to introduce
Augmented Reality (AR) technology using smartphone.

Fig. 5. Visitors with the VR goggles infront of the accelerator tank.

References[1] M. Furusaka et al., PASJ2022 FRP030. 2022, 984-988.
[2] HiSOR VR (Hiroshima Synchrotron Radiation Center VR) https://www.kasokuki-dx.jp/vr/[3] Unity Technologies https://unity.com/

50

7.
LIST OF PUBLICATIONS AND PRESENTATIONS

7.1

Peer-reviewed and proceedings papers

ACCELERATOR AND RERATED FACILITIES
1.

T. Moriguchi, A. Ozawa, Y. Yamato, M. Hayashi, R. Kagesawa, N. Kaname, M. Mukai, K. Tomita,
A. Yano, “Status of Lamb-shift polarized ion source at 6MV tandem accelerator in UTTAC and its
application to nuclear physics”, Proceedings of the 24th International Spin Symposium (SPIN2021),
JPS Conf. Proc. 37 (2022) 021201. [DOI: 10.7566/JPSCP.37.021201]

NUCLEAR AND ATOMIC PHYSICS
1. Y. Ishibashi, A. Gladkov, Y. Ichikawa, A. Takamine, H. Nishibata, T. Sato, H. Yamazaki, T. Abe,J. M. Daugas, T. Egami, T. Fujita, G. Georgiev, K. Imamura, T. Kawaguchi, W. Kobayashi,
Y. Nakamura, A. Ozawa, M. Sanjo, N. Shimizu, D. Tominaga, L. C. Tao, K. Asahi, H. Ueno,“Nuclear magnetic moment of the neutron-rich nucleus 21O”, Phys. Rev. C 107 (2023) 024306.
[DOI: 10.1103/PhysRevC.107.024306]
2. M. Tanaka, M. Takechi, A. Homma, A. Prochazka, M. Fukuda, D. Nishimura, T. Suzuki, T. Moriguchi,
D. S. Ahn, A. Aimaganbetov, M. Amano, H. Arakawa, S. Bagchi, K.-H. Behr, N. Burtebayev,
K. Chikaato, H. Du, T. Fujii, N. Fukuda, H. Geissel, T. Hori, 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, H. Sakurai, Scheidenberger, Y. Shimizu, T. Sugihara, T. Sumikama, H. Suzuki, S. Suzuki,
H. Takeda, Y. Tanaka, Y. K. Tanaka, I. Tanihata, T. Wada, K. Wakayama, S. Yagi, T. Yamaguchi,
R. Yanagihara, Y. Yanagisawa, K. Yoshida, T. K. Zholdybayev, “Charge-changing cross sections for
42-51

Ca and effect of charged-particle evaporation induced by neutron-removal reactions”,

Phys. Rev. C 106 (2022) 014617. [DOI: 10.1103/PhysRevC.106.014617]
3. H. F. Li, S. Naimi, T. M. Sprouse, M. R. Mumpower, Y. Abe, Y. Yamaguchi, D. Nagae, F. Suzaki,
M. Wakasugi, H. Arakawa, W. B. Dou, D. Hamakawa, S. Hosoi, Y. Inada, D. Kajiki, T. Kobayashi,
M. Sakaue, Y. Yokoda, T. Yamaguchi, R. Kagesawa, D. Kamioka, T. Moriguchi, M. Mukai, A. Ozawa,
S. Ota, N. Kitamura, S. Masuoka, S. Michimasa, H. Baba, N. Fukuda, Y. Shimizu, H. Suzuki, H. Takeda,
D. S. Ahn, M. Wang, C. Y. Fu, Q. Wang, S. Suzuki, Z. Ge, Yu. A. Litvinov, G. Lorusso, P. M. Walker,
Zs. Podolyak, T. Uesaka, “First application of mass measurements with the Rare-RI Ring reveals
the solar r-process abundance trend at A = 122 and A = 123”, Phys. Rev. Lett. 128 (2022) 152701.
[DOI: 10.1103/PhysRevLett.128.152701]

51

ACCELERATOR MASS SPECTROMETRY
1. H. Shen, G. Zhang, J. Tang, S. Shi, L. Wang, D. Chen, L. Qi, Y. Ouyang, X. Han, K. Wu, X. Sun,
H. Yun, Y. Bao, M. He, K. Sasa, S. Jiang, “A single-stage accelerator mass spectrometer and its
applications at Guangxi Normal University”, Nucl. Instrum. Methods Phys. Res. B 532 (2022) 68.
[DOI: 10.1016/j.nimb.2022.10.004]
2.

H. Shen, S. Shi, J. Tang, M. Qi, S. Wei, K. Sasa, M. Liu, L. Wang, G. Zhang, L. Qi, D. Chen, S. Gong,
G. Song, J. Dong, M. Wei, Y. He, “14C-AMS technology and its applications to an oil field tracer
experiment”, Radiocarbon 64 (2022) 1159. [DOI: 10.1017/RDC.2022.28]

3. H. Shen, J. Tang, L. Wang, M. Qi, Z. Li, S. Wei, K. Sasa, S. Shi, G. Zhang, D. Chen, L. Qi, N. Wang,
H. Zhou, M. He, Q. Zhao, Y. He, “New sample preparation line for radiocarbon measurements at the
GXNU laboratory”, Radiocarbon 64 (2022) 15011. [DOI:10.1017/RDC.2022.36]
4. K. Sasa, Y. Ochiai, Y. Tosaki, T. Matsunaka, T. Takahashi, M. Matsumura K. Sueki, “Chlorine-36
deposition at Tsukuba, Japan, after the Fukushima Daiichi Nuclear Power Plant accident”,
Nucl. Instrum. Methods Phys. Res. B 532 (2022) 73. [DOI: 10.1016/j.nimb.2022.10.003]
5. M. Kuwae, B. P. Finney, Z. Shi, A. Sakaguchi, N. Tsugeki, T. Omori, T. Agusa, Y. Suzuki, Y. Yokoyama,
H. Hinata, Y. Hatada, J. Inoue, K. Matsuoka, M. Shimada, H. Takahara, S. Takahashi, D. Ueno,
A. Amano, J. Tsutsumi, M. Yamamoto, K. Takemura, K. Yamada, K. Ikehara, T. Haraguchi, S. Tims,
M. Froehlich, L. K. Fifield, T. Aze, K. Sasa, T. Takahashi, M. Matsumura, Y. Tani, P. R. Leavitt, H. Doi,
T. Irino, K. Moriya, A. Hayashida, K. Hirose, H. Suzuki, Y. Saito, “Beppu Bay, Japan, as a candidate
Global Boundaries Stratotype Section and Point for the Anthropocene series”,
The Anthropocene Review 10 (2023) 49. [DOI: 10.1177/20530196221135077]
6. J. Tang, H. Shen, L. Wang, G. Z. Hang, L. Qi, D. Chen, Z. Li, S. Shi, M. Qi, He Ouyang, X. Han,
K. Wu, Y. Wang, B. Wu, Y. Xie, N. Wang, Y. He, K. Sasa, “A simple preparation system for Tritium andRadiocarbon at the GXNU laboratory”, Nucl. Instrum. Methods Phys. Res. B 535 (2023) 261.
[DOI: 10.1016/j.nimb.2022.11.026]

BEAM AND ISOTOPE APPLICATIONS
1. H. Kudo, M. Kurosawa, H. Naramoto, M. Sataka, S. Ishii, K. Sasa S. Tomita, “Determination ofhydrogen concentration in solids by transmission ERDA under nuclear-elastically enhanced recoilingof H by 8 and 9 MeV He”, J. Phys.: Condens. Matter 34 (2022) 435902.
[DOI: 10.1088/1361-648X/ac8b4e]52

2. H. Matsui and I. Yamaguchi, “Enhancement of self-field critical current density by several-tens-MeV
ion irradiation in YBa2Cu3O7 films prepared by fluorine-free metal-organic deposition”,
Jpn. J. Appl. Phys. 61 (2022) 043001. [DOI: 10.35848/1347-4065/ac5265]
3. T. Kameda, A. Nagata, Y. Kimura, R. Imai, P. Shrestha, K. Kimura, A. Yasuda, H. Watanabe, “Space
environment evaluation and low-earth-orbit demonstration of a communication component witha commercial transceiver integrated circuit”, Aerospace 9 (2022) 280.
[DOI: 10.3390/aerospace9060280]
4. N. Oishi, Y. Murao, N. Nitta, H. Tsuchida, S. Tomita, K. Sasa, K. Hirata, H. Shibata, Y. Hirano,
K. Yamada, A. Chiba, Y. Saitoh, K. Narumi, Y. Hoshino, “Morphological changes of nanostructures onsilicon induced by C60-ion irradiation”, J. Vac. Sci. Technol. A 40 (2022) 063103.
[DOI: 10.1116/6.0002073]
5. R. Murase, H. Tsuchida, S. Nakagawa, S. Tomita, A. Chiba, K. Nakajima, T. Majima, M. Saito,“Incident Energy Dependence of the Molecular Orientation Effect of MeV C2+ Projectiles inSecondary-Ion Emission Processes”, J. Phys. Soc. Jpn. 91 (2022) 024302.
[DOI: 10.7566/JPSJ.91.024302]
6. T. Hamada, S. Takase, A. Tanaka, K. Okada, S. Mineoi, A. Uedono, J. Ohshita, “Double-decker
silsesquioxane-grafted polysilsesquioxane hybrid films as thermal insulation materials”,
ACS Appl. Polym. Mat. 5 (2022) 743. [DOI: 10.1021/acsapm.2c01743]
7.

T. Umeda, K. Watanabe, H. Hara, H. Sumiya, S. Onoda, A. Uedono, I. Chuprina, P. Siyushev,
F. Jelezko, J. Wrachtrup, J. Isoya, “Negatively charged boron vacancy center in diamond”,
Phys. Rev. B 105 (2022) 165201. [DOI: 10.1103/PhysRevB.105.165201]

8. A. Uedono, N. Takahashi, R. Hasunuma, Y. Harashima, Y. Shigeta, Z. Ni, H. Matsui, A. Notake,
A. Kubo, T. Moriya, K. Michishio, N. Oshima, S. Ishibashi, “Vacancy-type defects in TiN/ZrO2/TiN
capacitors probed by monoenergetic positron beams”, Thin Solid Films 762 (2022) 139557.
[DOI: 10.1016/j.tsf.2022.139557]
9. S. Takase, T. Hamada, K. Okada, S. Mineoi, A. Uedono, J. Ohshita, “Organic-inorganic hybrid
thermal insulation materials prepared via hydrosilylation of polysilsesquioxane having hydrosilylgroups and triallylisocyanurate”, ACS Appl. Poly. Mat. 4 (2022) 372673.
[DOI: 10.1021/acsapm.2c00241]
10. T. Narita, A. Uedono, T. Kachi, “Effects of hydrogen incorporation on Mg diffusion in GaN-dopedwith Mg ions via ultra-high-pressure annealing”, Phys. Status Solidi B 259 (2022) 2200235.

53

[DOI: 10.1002/pssb.202200235]
11. L. Y. Li, K. Shima, M. Yamanaka, T. Egawa, T. Takeuchi, M. Miyoshi, S. Ishibashi, A. Uedono,
S. F. Chichibu, “Room-temperature nonradiative recombination lifetimes in c-plane Al1-xInxN epilayers
nearly and modestly lattice-matched to GaN (0.11 ≤ x ≤ 0.21)”, J. Appl. Phys. 132 (2022) 163102.
[DOI: 10.1063/5.0106540]
12. E. Kano, K. Kataoka, J. Uzuhashi, K. Chokawa, H. Sakurai, A. Uedono, T. Narita, K. Sierakowski,
M. Bockowski, R. Otsuki, K. Kobayashi, Y. Itoh, M. Nagao, T. Ohkubo, K. Hono, J. Suda, T. Kachi,
N. Ikarashi, “Atomic resolution analysis of extended defects and Mg agglomeration in Mg-ionimplanted GaN and their impacts on acceptor formation”, J. Appl. Phys. 132 (2022) 065703.
[DOI: 10.1063/5.0097866]
13. N. Shoji, K. Sasaki, A. Uedono, Y. Taniguchi, K. Hayashi, N. Matsubara, T. Kobayashi, T. Yamashita,“Effect of conversion on epoxy resin properties: Combined molecular dynamics simulation andexperimental study”, Polymer 254 (2022) 125041. [DOI: 10.1016/j.polymer.2022.125041]
14. Z. H. Li, T. T. Sasaki, A. Uedono, K. Hono, “Role of Zn on the rapid age-hardening in Mg-Ca-Zn
alloys”, Scr. Mater. 216 (2022) 114735. [DOI: 10.1016/j.scriptamat.2022.114735]
15. A. Uedono, H. Sakurai, J. Uzuhashi, T. Narita, K. Sierakowski, S. Ishibashi, S. F. Chichibu,
M. Bockowski, J. Suda, T. Ohkubo, N. Ikarashi, K. Hono, T. Kachi, “Effect of ultra-high-pressure
annealing on defect reactions in ion‐implanted GaN studied by positron annihilation”,
Phys. Stat. Sol. B 259 (2022) 2200183. [DOI: 10.1002/pssb.202200183]
16. S. F. Chichibu, H. Miyake, A. Uedono, “Impacts of Si-doping on vacancy complex formation and theirinfluences on deep ultraviolet luminescence dynamics in AlxGa1-xN films and multiple quantum wells
grown by metalorganic vapor phase epitaxy”, Jpn. J. Appl. Phys. 61 (2022) 050501.
[DOI: 10.35848/1347-4065/ac46b1]
17. T. Hamada, T. Goto, S. Takase, K. Okada, A. Uedono, J. Ohshita, “Structure-thermal property
relationships of polysilsesquioxanes for thermal insulation materials”,
Appl. Polym. Mat. 4 (2022) 2851. [DOI: 10.1021/acsapm.1c01812]
18. H. Okumura, Y. Watanabe, T. Shibata, K. Yoshizawa, A. Uedono, H. Tokunaga, S. Koseki, T. Arimura,
S. Sihkonen, T. Palacios, “Impurity diffusion in ion implanted AlN layers on sapphire substrates bythermal annealing”, Jpn. J. Appl. Phys. 61 (2022) 026501. [DOI: 10.35848/1347-4065/ac47aa]
19. C. Kodaka, M. Kishimoto, E. Kita, H. Yanagihara, “Crystal structure and magnetic properties ofhexagonal FeCo nitrides prepared using ammonia gas nitrification”,
IEEE Magn. Lett. 14 (2023) 2500105. [DOI: 10.1109/LMAG.2023.3262452]

54

7.2

Reviews and books

1. A. Ozawa, “Matter Radii and Density Distributions”, In: Handbook of Nuclear Physics, Springer,
Singapore, 2022. [DOI: 10.1007/978-981-15-8818-1 40-1]
2. 矢野朝陽, “反応断面積測定のための固体水素・重水素標的の開発”, 原子核研究 67 (2023) 15.

7.3

Poster and oral presentations

1. 矢野朝陽, 小沢 顕, 森口哲朗, 福田光順, 福留美樹, 高山 元, 田口 諒, 渡辺 薫, 田中聖臣,
鈴木 健, 山口貴之, 大久保研吾, 古泉 紫, 佐々木健太, 西村太樹, 網谷芽衣, 富山琢史,
中村佑生, 平山 瞳, 福嶋知隼, 大坪 隆, 野口法秀, 高津和哉, 小林侑希哉, 進藤楠月,
田澤有紀, 泉川卓司, 佐藤眞二, 福田茂一, 北川敦志, “He ガスセルを用いた固体水素標的の厚さの均一化”, 日本物理学会 2023 年春季大会, オンライン開催 (2023 年 3 月 22-25 日).
2. 矢野朝陽, 小沢 顕, 森口哲朗, 福田光順, 三原基嗣, 福留美樹, 高山 元, 木村容子, 田口 諒,
本多裕也, 林 双葉, 田中聖臣, 鈴木 健, 山口貴之, 神田真矩, 関 響咲, 大久保研吾,
古泉 紫, 佐々木健太, 西村太樹, 高橋弘幸, 菅原奏来, 宇根千晶, 大坪 隆, 野口法秀,
泉川卓司, 佐藤眞二, 福田茂一, 北川敦志, “不安定核の反応断面積測定に向けた固体重水素標的の開発”, 第 2 回日本量子医科学会学術大会, つくば国際会議場 (2022 年 12 月 9-10 日).
3. 森口哲朗, “非対称核物質の理解に向けた不安定核の反応断面積測定”, 筑波大学宇宙史研究センター2022 年度第 2 回構成員会議・成果報告&交流会, 筑波大学 (2022 年 11 月 28 日).
(招待講演)
4. 森口哲朗, “固体水素, 固体重水素標的を用いた反応断面積測定”, 反応断面積研究の新しい展
望 WS, 理化学研究所和光キャンパス (2022 年 11 月 9-10 日). (招待講演)
5. T. Moriguchi, “Development solid Hydrogen/Deuterium Target for reaction cross section
measurements”, Online seminar invited by Beihang University (Oct. 13, 2022). (Invited Talk)
6. 森口哲朗, “RI ビーム飛行時間検出器の開発 −理研稀少RI リングのための検出器− ”, 2021 年度
HIMAC 共同利用研究成果発表会, オンライン開催 (2022 年 5 月 30 日-6 月 1 日).
7. 松村 宏, 吉田 剛, 豊田晃弘, 中村 一, 桝本和義, 三浦太一, 別所光太郎, 松村万寿美,
森口哲朗, 笹 公和, “ガンマカメラ GeGI5 による加速器放射化の可視化の可能性の検討”,
第 4 回日本保健物理学会・日本放射線安全管理学会合同大会, 九州大学伊都キャンパス( 2022 年 11 月 24-26 日).

55

8. 吉田 剛, 松村 宏, 豊田晃弘, 中村 一, 桝本和義, 別所光太郎, 三浦太一, 松村万寿美,
森口哲朗, 笹 公和, “ガンマカメラ GeGI5 による加速器放射化の可視化実験”,
第 4 回日本保健物理学会・日本放射線安全管理学会合同大会, 九州大学伊都キャンパス (2022
年 11 月 24-26 日).
9. 吉田 剛, 松村 宏, 松村万寿美, 豊田晃弘, 中村 一, 桝本和義, 三浦太一, 笹 公和, 森口哲朗,“可搬型 γ 線イメージング装置 GeGI5 による筑波大タンデムの加速器放射化イメージング -加速器の放射化イメージングへの挑戦- ”, 第 34 回タンデム加速器及びその周辺技術の研究会, 日本
原子力研究開発機構 原子力科学研究所, オンライン開催 (2022 年 7 月 21-22 日).
10. 笹 公和, “筑波大学タンデム加速器施設の東日本大震災からの復旧, 復興, その後の発展”,
日本原子力学会 2022 年秋の大会, 加速器・ビーム科学部会企画セッション,
茨城大学日立キャンパス (2022 年 9 月 8 日). (招待講演)
11. 笹 公和, “加速器質量分析法による宇宙線生成核種の検出と地球化学への応用”,
日本地球化学会第 69 回年会, 高知大学 (2022 年 9 月 7 日). (招待講演)
12. 笹 公和, “加速器質量分析法における環境中の難測定核種の検出技術に関する進展”,
日本放射化学会第 66 回討論会, 東京大学 ( 2022 年 9 月 15 日). (招待講演)
13. 笹 公和, 石井 聰, 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”, 日本加速器学会第 19 回年会, オンライン開催( 2022 年 10 月 18-21 日).
14. 笹 公和, 椎根大輔, 高橋 努, 松村万寿美, 坂口 綾, “6MV タンデム加速器を用いた長半減期放射性セシウム 135 の加速器質量分析法の開発”, 日本加速器学会第 19 回年会,
オンライン開催 (2022 年 10 月 18-21 日).
15. 笹 公和, 石井 聰, 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”, 第 34 回タンデム加速器及びその周辺技術の研究会, 日本原子力研究開発機構 原子力科学研究所, オンライン開催 (2022 年 7 月 21-22 日).
16. 松中哲也, 長尾誠也, 井上睦夫, 田中さき, 熊本雄一郎, 谷内由貴子, 葛西広海, 森田貴己,
三木志津帆, 高橋 努, 松村万寿美, 末木啓介, 笹 公和, “北極海とオホーツク海におけるヨウ素
129 の水平分布解析”, 日本海洋学会 2022 年度秋季大会, 名古屋大学東山キャンパス,ハイブリッド開催 (2022 年 9 月 3-7 日及び 12 日).
17. 松中哲也, 落合伸也, 松村万寿美, 高橋 努, 末木啓介, 笹 公和, “能登半島における 1950 年以降の I-129 と Cs-137 の沈着量変動”, 日本放射化学会第 66 回討論会, 東京大学

56

(2022 年 9 月 15 日～17 日).
18. 冨田成夫, 平賀真瑠古, 畑田颯太, 椎名陽子, 高橋 努, 石井 聰, 笹 公和, “高速分子イオン入射によるコンボイ電子生成におけるイオン種依存性”, 第 23 回「イオンビームによる表面・界面の解
析と改質」特別研究会, 若狭湾エネルギー研究センター (2022 年 12 月 2-3 日).
19. 冨田成夫, 平賀真瑠古, 畑田颯太, 椎名陽子, 高橋 努, 石井 聰, 笹 公和, “コンボイ電子収量におけるクラスター効果の入射粒子依存性 III”, 日本物理学会 2002 年秋季大会,
東京工業大学大岡山キャンパス (2022 年 9 月 12-15 日).
20. 冨田成夫, 平賀真瑠古, 畑田颯太, 椎名陽子, 高橋 努, 石井 聰, 笹 公和, “コンボイ電子収量におけるクラスター効果の消失膜厚”, 日本物理学会 2023 年春季大会, オンライン開催(2023 年 3 月 22-25 日).
21. 松村万寿美, 笹 公和, 松中哲也, 高橋 努, 坂口 綾, 末木啓介, “加速器質量分析に携わる実験室のヨウ素 129 降下量調査 (2022 年夏季)”, 第 23 回 AMS シンポジウム, 山形大学
(2022 年 12 月 1-2 日).
22. 笹 公和, 高橋 努, 松村万寿美, 松中哲也, 坂口 綾, 末木啓介, “筑波大学 6 MV タンデム加速器質量分析装置における多核種 AMS と応用研究の現状”, 第 23 回 AMS シンポジウム, 山形大学
(2022 年 12 月 1-2 日).
23. 三宅芙沙, 箱崎真隆, R. Hantemirov, 早川尚志, S. Helama, 堀内一穂, A. J. T. Jul, 木村勝彦,
前原裕之, 宮原ひろ子, 森谷 透, M. Oinonen, I. P. Panyushkina, 笹 公和, 武山美麗, 門叶冬樹,“過去 1 万年間の極端太陽高エネルギー粒子現象の調査”, 第 23 回 AMS シンポジウム,
山形大学 (2022 年 12 月 1-2 日).
24. 冨田成夫, 平賀真瑠古, 畑田颯太, 尾関海太, 椎名陽子, 高橋 努, 石井 聰, 笹 公和,“コンボイ電子収量におけるクラスター効果の消失膜厚”, 日本物理学会 2023 年春季大会, オンラ
イン開催 (2023 年 3 月 22-25 日).
25. 笹 公和, 椎根大輔, 高橋 努, 松村万寿美, 坂口 綾, “加速器質量分析法による長半減期放射性セシウム 135 の高感度検出試験”, 2023 年第 70 回応用物理学会春季学術講演会, 上智大学
(2023 年 3 月 15-18 日).
26. 松井浩明, 山口 巌, “イオン照射による Y 系高温超伝導膜の自己磁場中臨界電流密度制御”, 応
用物理学会秋季学術講演会, 東北大学 (2022 年 9 月 19-23 日).
27. C. Kodaka, M. Kishimoto, E. Kita, H. Yanagihara, “Crystal structure and magnetic properties of FeCo

57

nitrides prepared by ammonia gas nitrification”, The 11th International Conference on Fine Particles
Magnetism (ICFPM 2022), Yokohama, Japan (Oct. 16-21, 2022).
28. E. Kita, R. Onodera, M. Kishimoto, H. Yanagihara, “Magnetic relaxation of superparamagnetic Fe oxide
particles studied with Mössbauer spectroscopy”, The 11th International Conference on Fine Particles
Magnetism (ICFPM 2022), Yokohama, Japan (Oct. 16-21, 2022).

7.4

UTTAC seminars

2023.1.10

Measurement of azimuthal anisotropy of jets and electrons from heavy quarks in Pb-Pb
collisions at √𝑠= 5.02 TeV with LHC-ALICE, Ryotaro Nagata (University ofTsukuba)
2023.1.10

Particle number fluctuations of protons, kaons and pions in √𝑠= 19.6 GeV Au+Au

collisions at RHIC-STAR experiment, Kazuki Iwanaga (University of Tsukuba)
2023.1.10

Measurements of the first to third order azimuthal anisotropies from the Beam Energy Scanin Au+Au collisions at RHIC-STAR experiment, Shun Oike (University of Tsukuba)

2023.1.10

Developments of solid hydrogen and solid deuterium targets for reaction cross section
measurements of unstable nuclei, Asahi Yano (University of Tsukuba)

58

8.
THESES(From a free-use drawing on web)Doctor thesis
Tianjing Yang

Study on strain improvement of Aurantiochytrium by genetic engineering andrandom mutagenesis

Master theses
Asahi Yano

Developments of solid hydrogen and solid deuterium targets for reaction crosssection measurements of unstable nuclei（不安定核の反応断面積測定に用いる固体水素標的と固体重水素標的の開発）

Souta Hatada

Development of radiation measurement system using FPGA（FPGA を用いた放射線計測システムの開発）

Shingo Oshida

Characterization of vacancy-type defects in NiAl using positron annihilation
spectroscopy（陽電子消滅法を用いた NiAl の空孔型欠陥評価）

Naomichi Takahashi

Characterization of vacancy-type defects in a TiN/ZrO2/TiN capacitor using
positron annihilation spectroscopy（陽電子消滅法を用いた TiN/ZrO2/TiN
キャパシタの空孔型欠陥の評価）

Saki Tanaka (Kanazawa
University)

Variation factor of polycyclic aromatic hydrocarbons in surface seawater of the
Sea of Japan and Arctic Ocean（日本海および北極海表層における多環芳
香族炭化水素類の変動要因解析）

Undergraduate theses
Uta Ozeki

Calibration of 1MV Tandetron generating voltage meter with energy
measurement of covoy electrons （コンボイ電子を用いた 1MV タンデト
ロン加速器の GVM 較正）

Koudai Tanabe

Trajectory calculation for transport of charged particles by a 90-degree
magnet（90度マグネットによる荷電粒子輸送軌道の計算）

Kazuki Yamamoto

Hydrogen analysis of a neutron-reflecting material using ERDA（ERDA による中性子反射材料の水素分析）

Kento Sato (Hirosaki
University)

Variation of nuclear test produced 36Cl in the H15 ice core at the East Antarctic
coastal region（東南極沿岸域 H15 アイスコアに刻まれた核実験起源の
36
Cl 変動）

59

9.
LIST OF PERSONNEL

Three students are watching hydrogen signals in the T-ERDA
experiment using the 6MV tandem accelerator.
−−− Report 4.4

Tandem Accelerator Complex
A. Uedono

Director, Professor

K. Sasa

Associate Professor

D. Sekiba

Lecturer

T. Moriguchi

Assistant Professor

S. Ishii

Mechanical Engineer

T. Takahashi

Electrical Engineer

Y. YamatoElectrical Engineer

T. Yoshida

Electrical Engineer

M. Matsumura

Technical Staff

S. Kuramochi

Administrative Staff

N. Shimada

Administrative Staff

H. Muromachi

Administrative Staff

M. Watanabe

Administrative Staff

Research Members 1
Department of Physics, Institute of Pure and Applied Sciences
A. Ozawa

T. Moriguchi

K. Sasa

T. Yamaguchi (Saitama University [Cross appointment])
Department of Applied Physics, Institute of Pure and Applied Sciences
E. Kita

D. Sekiba

S. Sharmin

A. Uedono

H. Yanagihara

H. Tanimoto

S. Tomita

Department of Chemistry, Institute of Pure and Applied Sciences
K. Sueki

A. Sakaguchi

S. Yamasaki

Department of Geosciences, Institute of Life and Environmental Sciences
M. Kurosawa
Department of Biology, Institute of Life and Environmental Sciences
I. Suzuki
Department of Intelligent Interaction Technologies, Institute of Systems and Information Engineering
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.

60

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 Science and Technology
T. Amagai

N. KishiT. Yang

Z. ShiA. YanoS. Hatada

T. Okamoto

Y. Yu

M. Hiraga

S. KuboT. Nakamura

S. Oshida

N. Takahashi

R. Hioki

K. Torii

K. Honma

T. Kanazawa

C. Kodaka

S. Jung

R. Takatsuki

R. Tanaka

Y. Kurihara

H. Yoshikado

U. Ozeki

Y. SekiY. Tanabe

K. Yamamoto

Y. AbeT. Takahashi

H. Tanaka

R. Minami

Undergraduates

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)

H. Matsui

National Institute of Advanced Industrial Science and Technology (AIST)

T. Matsunaka

Kanazawa University

M.Rodorigo

Kanazawa University

S. Tanaka

Kanazawa University

M. Ozawa

Kanazawa University

G. YoshidaHigh Energy Accelerator Research Organization (KEK)

H. Matsumura

High Energy Accelerator Research Organization (KEK)

A. Toyoda

High Energy Accelerator Research Organization (KEK)

K. Mishima

High Energy Accelerator Research Organization (KEK)

S. Kawasaki

High Energy Accelerator Research Organization (KEK)

K. Horiuchi

Hirosaki University

61

K. Sato

Hirosaki University

R. Shimizu

Tokyo Institute of Technology

Y. Komatsu

Tokyo Institute of Technology

M. Honda

Japan Atomic Energy Agency (JAEA)

A. Ishiyama

Saitama University

Y. Nagami

Saitama University

K. Takiura

Saitama University

S. Otsuka

Saitama University

T. Suzuki

Saitama University

62