UTTAC-86, 2017

UTTAC
ANNUAL REPORT 2016

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

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

UTTACANNUAL REPORT 2016
April 1, 2016 – March 31, 2017

UTTAC-86, 2017

Editors : Tetsuaki Moriguchi, Kimikazu Sasa,Yoshihiro Yamato, Masumi Matsumura,
Masao Sataka, Hiroshi Naramoto, and Hiroshi Kudo

UTTAC ANNUAL REPORT is a series of issues, which include annual reports of
Tandem Accelerator Complex, Research Facility Center
for Science and Technology, University of Tsukuba.
Copyright © 2016 by Tandem Accelerator Complex, Research Facility Center
for Science and Technology, University of Tsukuba and individual contributors.
All reports are written on authors’ responsibility and thus the editors are not liable
for the contents of the report.

Tandem Accelerator Complex, Research Facility Center for Science and Technology,
University of Tsukuba
Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577, Japanannual@tac.tsukuba.ac.jp

PREFACE
This annual report covers researches carried out at University of Tsukuba Tandem
Accelerator Complex (UTTAC) during the fiscal year 2016 (1 April 2016 ∼ 31 March2017). The topics include not only accelerator-based researches using the 6MV Pelletron,
1 MV Tandetron, and 1MV Cockcroft-Walton accelerators, but also radioisotope-based
researches including positron annihilation spectroscopy and Mössbauer spectroscopy.
September 30, 2017
Editors-i-Long and dark years finally ended!
Construction of a new horizontal-type 6 MV Pelletron tandem accelerator was started immediately
after the previous accelerator was lost suddenly by the 2011 earthquake. It was completed in 2014,
however, it took two more years for legal procedures and the setup of experimental apparatus. Indeed, theexperimental use of the accelerator was started in March 2016. The long and dark five years finallyended. Photos below were taken at the opening ceremony and the celebration party, 1 July 2016.

- iii -

CONTENTS

1. ACCELERATOR AND RELATED FACILITIES
1.1

Accelerator operation 2016 ···········································································

1

1.2

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

3

1.3

Development of an ion microbeam scanning system in the 6 MV tandem accelerator
facility····································································································

5

1.4
1.5

Characteristics of irradiation-test chamber for semiconductor devices devices···············
Approach to possible maximum energies of high Z ions accelerated by the 6 MV tandem
accelerator································································································

7
9

2. NUCLEAR AND ATOMIC PHYSICS
2.1

Production of unstable nuclei by proton-capture reactions with a Si target·····················

11

2.2

The qualification test of sulfur targets for intense beam irradiation ·····························

12

2.3

Test experiment for the isotope analysis of sulfuric acids generated in atmospheric air byproton irradiation ······················································································· 14

3. ACCELERATOR MASS SPECTROMETRY
3.1

Operation of the Tsukuba 6 MV multi-nuclide AMS system for the year 2016················

16

3.2

36

18

3.3

36

Cl/Cl and 36Cl inventory in surface soils near the Fukushima Dai-ichi Nuclear Power
Plant ···································································································· 20

3.4

Determination of I-129 in radioactive particles by AMS ········································

22

3.5

Preparation of a 129I standard solution for ICP-MS/MS ·········································

24

3.6

Performance evaluation of the AMS-measurement of iodine-129 by the 6 MV tandem
accelerator at University of Tsukuba ·······························································

25

Reconstruction of temporal variation for anthropogenic radionuclides
in the Japan Sea using a coral core sample ························································

27

Radiocarbon variations since 1960 in tree rings near the Tokai nuclear facilities inJapan······································································································

28

3.7
3.8
3.9

Cl AMS measurements with the 6 MV tandem accelerator·····································

41

Trial of determination of Ca concentration in iron meteorites by accelerator mass
spectrometry·····························································································

30

4. BEAM AND ISOTOPE APPLICATIONS
4.1

Probing the effect of point defects on the leakage blocking capability of Al0.1Ga0.9N/Si
structures using a monoenergetic positron beam ·················································

-v-

32

4.2

Study of cathode shape effect on the reliability of ΔE-E telescope ERDA·····················

34

4.3

Trial production of preamplifier for multi-channel SSD··········································

36

4.4

Micro-PIXE analyses of pyrite in sea-floor sediments·············································

38

4.5

Mössbauer effect of CuFe2O4 spinel fine particles under external magnetic field············

41

4.6

Low temperature Mössbauer study on spherical α”-Fe16N2 core–shell nanoparticles withhigh magnetic anisotropy··············································································

43

4.7

Characterization of oxide thin films with RBS technique·········································

45

4.8

Low temperature synthesis of highly oriented Si1-xGex (x: 0–1) on an insulator by
Al-induced layer exchange············································································

47

Quantitative analysis of light elements in mixed-anion compound thin films··················

49

4.10 Oxygen reduction reaction catalytic site analysis by Mössbauer spectroscopy················

51

4.11 Sputtering loss of Zn nanoparticles in SiO2 induced by MeV C60+ ion irradiation············

52

4.12 HR-RBS study of the rutile TiO2(110) surface······················································

54

4.13 Profiling of hydrogen in thick films employing transmission ERDA technique···············

55

4.14 Heterogeneous carboxy group distribution across a polyamide active layer of a ESPA2
thin-film composite reverse osmosis membrane····················································

57

4.15 Relationship between the abrasion of DLC coated layer and its hydrogen content············

59

4.16 Measurement of hydrogen content in DLC films···················································

61

4.9

5. BEAM IRRADIATION EFFECT
5.1

Tolerance evaluation on single event of COTS-GNSS receivers·································

63

5.2

Preliminary evaluation of single event testing for regular use of the 6 MV tandem
accelerator at University of Tsukuba·································································

64

Effect of helium irradiation on tritium permeability of erbium oxide···························

66

5.3

6. LIST OF PUBLICATIONS AND PRESENTATIONS
6.1

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

67

6.2

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

72

6.3

Proceedings······························································································

72

6.4

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

72

6.5

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

79

6.6

Symposium······························································································

80

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

83

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

84- vi -

1.
ACCELERATOR AND RELATED FACILITIES1.1

Accelerator operation 2016

K. Sasa, S. Ishii, H. Oshima, Y. Tajima, T. Takahashi, Y. Yamato, D. Sekiba, T. Moriguchi, A. Uedono
In the fiscal year (FY) 2016, we operated and maintained the 1 MV Tandetron accelerator, the 6 MV
Pelletron tandem accelerator, and the apparatus utilizing radio-isotopes. The total service time of UTTAC
in this FY was 174 days (4,176 hours).
1 MV Tandetron accelerator
The 1 MV Tandetron accelerator has two types of negative ion sources and four beam lines. In FY 2016,
the operating time and the experimental beam time of the Tandetron were 594.3 and 262.1 hours,
respectively. The Tandetron had 73 working days for beam experiments. Totally, 66 research programs
were carried out and 538 researchers used the Tandetron. Figure 1 shows the percentage of accelerated
ions. Figure 2 shows the percentage of research fields for the Tandetron.

Education
14.1%

C
27.0%

H
30.4%

Developments(Instruments andDetectors)
22.3%

He
42.7%

RBS/ERDA
36.6%

NRA
1.6%
PIXE
25.4%

Fig. 1. Percentage of accelerated ions for the

Fig. 2. Percentage of research fields for the 1
MV Tandetron accelerator in FY 2016.

1 MV Tandetron accelerator in FY 2016.

6 MV Pelletron tandem accelerator
For the 6 MV Pelletron tandem accelerator, routine beam delivery and experiments were started on
March 1 2016 [2]. We had no trouble in operating the accelerator until just before the end of 2016. At theend of 2016, however, a malfunction occurred in the foil changer which replaces carbon stripper-foils at
the accelerator terminal. After urgent repair of the foil changer, the accelerator was back into goodcondition on January 2017.
In FY 2016, the operating time and the experimental beam time of the Pelletron were 1867 and 1496.4
hours, respectively. The Pelletron had 154 working days for beam experiments. Totally, 95 research
programs were carried out and 614 researchers used the Pelletron. Figure 3 shows the beam time1

histogram with respect to the terminal voltage. Figures 4 and 5 show the percentages of accelerated ionsand of research fields, respectively, for the Pelletron.

The operating time with the maximum terminal

voltage of 6 MV occupied 37% of all the beam time. Two thirds of the beam time was used for AMS
studies. In AMS, radionuclides of 14C, 36Cl, 41Ca and 129I were accelerated during most of the operating
hours.

Terminal Voltage (MV)

6
5
4
3
2
1
0

100

200

300

400

500

600

Beam Time (hours)

Fig. 3. Beam time histogram as a function of the terminal voltage for the 6 MV
Pelletron tandem accelerator in FY 2016.

Ag
0.2%

I 22.8%

Br
0.2%
Ni
1.0%

Ca 8.6%

Education
5.5%

Cosmic ray
experiments
2.2%
Radiation
tolerance test
6.7%

Au 0.5%

H 15.5%Be
He 5.9% 1.2%

Beam test 0.1%

Nuclear physics
4.1%

Microbeam
11.2%

B
0.3%
C 16.1%AMS
64.8%

Cl 21.2%
N
1.8%
O
Si
F
Al
1.3% 2.1% 0.1% 1.2%

IBA（RBS/ERDA/NRA/PIXE)
5.5%

Fig. 5. Percentage of research fields for the 6 MV
Pelletron tandem accelerator in FY 2016.

Fig. 4. Percentage of accelerated ions for the 6 MV
Pelletron tandem accelerator in FY 2016.

References[1] K. Sasa et al., Nucl. Instr. Meth. B 361 (2015) 124.
[2] K. Sasa et al., UTTAC Annual Report 2015, UTTAC-85 (2016) 1.

2

1.2

Development of the Lamb-shift polarized ion source

T. Moriguchi, Y. Yamato, A. Ozawa, S. Suzuki, M. Amano, D. Kamioka
The reconstruction of the Lamb-shift polarized ion source (PIS), which was damaged seriously by theGreat East Japan Earthquake, was mostly finished [1]. We therefore began to generate polarized beams. A
spin filter (SF), which is one of the devices constituting PIS, is of significance for the nuclear polarization[2]. SF was designed to provide (1) a uniform magnetic field parallel to the beam axis, (2) a 1610 MHz
radio-frequency (RF) electric field parallel to the beam, and (3) a static electric field perpendicular to thebeam. In order to produce the polarized beam, it is necessary to adjust these parameters of SF properly. In
this fiscal year, we tuned the magnetic field and the RF electric field of SF, and tried to generate polarized
proton and deuteron beams.
Firstly, we measured the magnetic field parallel to the beam axis against electric current supplied forthe electromagnet. Prior to the measurements, a Hall probe (DTM-151, Group3 Technology Ltd.) mounted
on an axial holder was installed into the center of the beam axis inside SF after removing an argon gas
chamber, which are located just downstream of SF. Figure 1 shows the results. The finite magnetic fieldseen at 0 A is induced by other coils for the correction of the fringing field. Except for this external field,
the good linearity between the magnetic field and electric current is confirmed.
Next, we measured oscillation frequency for the RF electric field and a resonance frequency of SF.
The oscillation frequency was measured using the spectrum analyzer (MS2721B, Anritsu) which wasconnected between the output of the power supply and the input of the RF electric field of SF. The
oscillation frequency thus obtained is 1610 MHz, as is expected. The resonance frequency of SF was
measured by a network analyzer (8753ET, Agilent). For stabilization of SF, the power supply was turnedon 25 hours before this measurement. In order to investigate the shift of the resonance frequency due tochange in the temperature of SF, we measured again in two hours after the power supply was turned off.
The results are shown in Fig. 2. The resonance frequency of SF was 1609.475 MHz which is shifted fromthe oscillation frequency of 1610 MHz. After the power supply was turned off, the resonance frequency
was shifted towards the oscillation frequency, possibly by self-cooling of SF.
Then, we performed a test for generating the polarized beam. In order to prevent the shift of theresonance frequency, two large-sized air fans were used to cool SF. The beam current was measured by the
Faraday cup (FC-PIS) located downstream of PIS. Figure 3 shows the measured beam current as afunction of the magnetic field of SF. Actually, the negative current was measured because negatively
charged proton or deuteron were extracted from PIS. For proton, we found two resonance peaks around
540 and 605 G, which correspond to the nuclear spin magnetic quantum number mI = +1/2 and −1/2,
respectively. The polarization of mI = +1/2 peak was about 80% by using a quenching method. For
deuteron, we found three resonance peaks around 565, 575 and 585 G, which correspond to mI = +1, 0 and−1, respectively. These resonance peaks for proton and deuteron were not observed without cooling of SF.
For generation of the polarized beam from PIS, it is important to control the temperature of SF so as toadjust the resonance frequency of SF to the oscillation frequency of the power supply. As the next step, we

3

will improve the cooling system of SF and measure the polarization at the end of the experimental beamcourse by using a polarimeter via a nuclear reaction.
We acknowledge the technical support of Drs. Y. Tagishi and M. Tomizawa. We would like to thank
NIHON KOSHUHA Co., Ltd. staff for measurements of the oscillation and resonance frequencies.

Fig. 2. Power loss of the RF electric field as afunction of frequency. On and Off indicate“before” and “after” the power supply is turned off,
respectively (see the text).

Fig. 1. Magnetic field of SF as a function ofcurrent from the power supply.

Fig. 3. Beam current measured by the Faraday cup (FC-PIS)
as a function of the magnetic field.

References[1] T. Moriguchi et al., UTTAC Annual Report 2014 (2015) 7.
[2] Y. Tagishi et al., Nucl. Instr. Meth. 164 (1979) 411.

4

1.3

Development of an ion microbeam scanning system in the 6 MV tandem accelerator facility

A. Yamazaki, K. Sasa, S. Ishii, M. Kurosawa, S. Tomita, H. Naramoto, M. Sataka, H. Kudo, A. Uedono
Light trace elements in structural materials sensitively affect materials’ properties. Many researchers
have paid much attention to microstructural analysis of the relevant elements. Ion beam can provide
various elemental analyses in materials. Combining ion beam focusing and scanning techniques, we canobtain spatial distribution of elements.
The ion microbeam system has been constructed in 2016 at UTTAC [1]. Schematic view of the ion
microbeam line is shown in Fig. 1. This system will be mainly used for analysis of light elements instructural materials, based on various interaction processes of incident ions with the elements.

Fig. 1. Schematic view of the ion microbeam line of the 6 MV tandem accelerator facility (lengh isindicated in mm). A new large target chamber is shown at the end of the microbeam line.

Particle induced X-ray emission (PIXE) has been widely used for analysis of trace elements. For
X-ray measurements, a silicon drift detector (SDD) with a thin front window has been installed, and asuperconducting tunnel junction (STJ) array detector [2, 3] will be installed for sensitive PIXE analysesof light elements.
Analysis of hydrogen in materials is of both academic and practical importance because hydrogenplays an important role for determining the mechanical properties of materials. The PIXE method is notapplicable to hydrogen analysis because of no characteristic X-ray emission from hydrogen. Hydrogencan be detected using ion beams by applying nuclear reaction analysis (NRA) or elastic recoil detection
analysis (ERDA). To support these techniques, a large target chamber has been installed. This is designed
for multi-purpose analysis; to utilize not only SDD and STJ detector but also a BGO detector for NRA.
Furthermore, a silicon surface barrier detector was set up for elastic recoil detection analysis (ERDA) .
Figure 2 shows a top view of the new chamber. It is 240 mm in inner diameter and 228 mm in height.
The SDD and STJ detector are placed at 135◦ and at −90◦ relative to the beam direction, respectively. A
PIN photodiode which is used for estimating the diameter of a focused ion beam by scattering transmission
ion microscopy (STIM) is installed at 0◦ port with a Faraday cup. BGO detector for NRA can be installedat the same port in replace of the photodiode and Faraday cup assembly. Silicon surface barrier detectors
for ERDA and RBS can also be installed in the chamber.

5

Fig. 2. Top view of the new target chamber and arrangement of the detectors.

Samples are fixed on the three-dimensional positioning stage. The horizontal and vertical positioning
ranges are 15 mm and 50 mm, respectively. It can also move along the beam axis within 10 mm to set thesurface of the sample at the center of the chamber. A digital microscope is fixed on the chamber to view
the sample normally through a mirror which is positioned on the beam axis and is held obliquely at 45◦ .
Ion beam transport and focusing were carried out mainly with 6 MeV protons. Figure 3 shows anexample of STIM images of a copper fine grid (1000 lines per inch, 6 µ m grid width) which was obtainedby scanning of focused protons. The estimated beam diameter is 2 µ m.

Fig. 3. STIM image of the copper fine grid (1000 lines per inch) using a 6 MeV proton beam.

References[1] A. Yamazaki et al., Nucl. Instrum. Methods B 404 (2017) 92.
[2] M. Ukibe et al., X-ray Spectrom. 40 (2011) 297.
[3] S. Shiki et al., J. Low Temp. Phys. 167 (2012) 748.

6

1.4

Characteristics of irradiation-test chamber for semiconductor devices

M. Sataka, K. Sasa, H. Naramoto, H. Kudo
Single-event phenomena in microelectronics devices are caused in the space environment by highenergy particles which impinge on the sensitive regions of the devices [1,2]. In recent years, there has
been increasing attention in the possible use of commercial electronic devices for space applications. It isalso noted that even on the ground the microelectronic devices are susceptible from secondary cosmic rays
that are induced by primary neutrons, and from alpha emitters such as U and Th contaminants within chippackaging materials.
The new irradiation-test chamber dedicated for semiconductor devices was installed in a beam courseof the 6 MeV tandem accelerator at UTTAC in 2015. This chamber consists of main and sub chambers
which are differentially evacuated by two turbo molecular pumps. The base pressures are 2×10-5 Pa and1×10-6 Pa, respectively. The overview of the irradiation-test chamber is shown in Fig. 1. On the upstreamside, installed is the beam handling sub chamber containing slits, aperture, foils, and a Faraday cup. The
main chamber is about 1000 mm in diameter and about 750 mm in height. In the beam shutter system, twolinear motion feedthroughs and the target stage are built together. The liner motion feedthrough covers a
distance of 150mm with the resolution of 0.01mm. The target stage, on which a sample holder up to socalled A5 size (140mm×210mm) can be mounted, enables four different movements (two independenttranslations and two independent rotations). These are controlled by the driver-handling system
implemented in the LabVIEW environment.

Fig. 1. Overall view of the irradiation-test chamber for semiconductor devices.

7

The details of sample setting are shown in Fig. 2. The specification of target stage is summarized inTable 1. This test chamber will be also useful for various kind of ion irradiation on materials since thebasic mechanisms required for the controlled irradiation experiments are already built in this chamber. We
have also introduced an ion beam scanning system for uniform irradiation with various intensity levels
from faint to intense ion beam.

Fig. 2. Inside view of the main chamber, showing the target stage and the goniometer system.

Table 1. Specification of the goniometer system for target stage control.
x-travel±74 mmy-travel±105mmθ-rotation+30 ~ −90 degree

ϕ-rotation±90 degree

References[1] M. Komatsu et al., this annual report 5.1 (2017).
[2] A. Maru et al., this annual report 5.2 (2017).

8

1.5

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

M. Sataka, K. Sasa, H. Naramoto, T. Takahashi, H. Kudo
A tandem-type accelerator can provide many kinds of ion species with wide energy ranges, comparedwith a single-stage electrostatic accelerator. Because of such wide variety of ion beams, tandem
accelerators have been used for comprehensive studies of electronic excitation processes in materials.
Furthermore, tandem accelerators allow irradiation-tolerance tests under wide experimental parameters ofelectronic devices to be operated in space. At the present stage of the irradiation-test experiments at
UTTAC, we need a systematic data base concerning the maximum energies of high Z elements which are
obtained from the 6 MV tandem accelerator.
We have measured the beam current distribution of accelerated ions as a function of ion charge,
employing Ar gas as the charge stripper. Figure 1 shows the beam current distribution of iodine ions at theterminal voltage of 6 MV. The beam current is maximal at the ion charge of 6, and it decreases drasticallyas the ion charge increases. In a critical use of the 6 MV tandem accelerator, an I14+ beam of the highest
energy 90 MeV is available1. Similar data were obtained for He, O, F, Si, Cl, Ni, Br, Ag, and Au.

Ion Current (nA)

1000

100

10

1
5

6

7

8

9

10

11

12

13

14

15

Ion Charge

Fig. 1. Beam current distribution of iodine ions accelerated by the 6 MV
tandem accelerator at the terminal voltage of 6 MV.

Table 1 summarizes the availability of tested ion species. In this table, ion charge, ion energy and ion
current range are listed. There appear some uncertainties in the data for acceleration of highly charged ions ofBr, Ag and Au. This is mainly due to electron loading, however it can be fixed after some improvement. Similar
data base for B and C will be complemented soon, and the tests for medium heavy ions such as Cl, Ni, and Br
will be easily performed using a foil stripper at the high voltage terminal of the accelerator.

1

Calculated as (14+1)×6=90 (MeV).

9

Table 1. Availability of the ion species at the terminal voltage of 6 MV: ○:≥1nA, △: ≤1nA.
Charge Energy
state
（MeV）
14
90
13
84
12
78
11
72
10
66
9
60
8
54
7
48
6
42
5
36
4
30
3
24
2
18
1
12

He

O

◯
◯

◯
◯

F

◯
◯
◯
◯
◯

Si

Ion Species
Cl
Ni

◯
◯
◯
◯
◯
◯

△
◯
◯
◯
◯
◯
◯
◯
◯
◯

10

△
◯
◯
◯
◯

Br
△
◯
◯
◯
◯
◯
◯
◯
◯
◯

Ag
△
△
◯
◯
◯
◯
◯
◯
◯
◯

I
◯
◯
◯
◯
◯
◯
◯
◯

Au
△
△
◯
◯
◯
◯
◯

2.
NUCLEAR AND ATOMIC PHYSICS

2.1

Production of unstable nuclei by proton-capture reactions with a SitargetA. Ozawa, T. Moriguchi, M. Amano, D. Kamioka, S. Suzuki
We are attempting to produce polarized unstable nuclei by proton-capture reactions with polarized
proton beams in the aim of measuring nuclear moments of unstable nuclei. Up to now we have tried to
produce unstable nuclei by proton-capture reactions using Mg and Si targets in 1 MV Tandetron [1]. Fromthe γ ray measurement with the Ge detector, it was confirmed that unstable nuclei 25Al (T1/2 = 7.1 s) and30

P (T1/2 = 150 s) could be produced for each target [1]. In FY2016, we shifted to 6MV tandem accelerator,

which began to operate in March 2016, and started an experiment there.
In FY2016 we performed an experiment using a non-polarized proton beam. The proton beam
accelerated to 3 MeV by a 6 MV tandem accelerator was irradiated on a 0.5 mm thick Si target placed in achamber located in the A6 course. The proton beam induces the proton-capture reactions including
resonant reactions until it stops in the Si target. Natural Si has three stable isotopes (28Si: 92.2%, 29Si:
4.7%, 30Si: 3.1%). Among 29P, 30P, and 31P, that can be produced by the proton-capture reactions in the Sitarget, 29P (T1/2 = 4.1 s) and 30P are unstable nuclei with β decays. In order to measure β rays associatedwith the β decays, two plastic scintillators werelocated on top of the target (plastic thicknesses
1 mm and 2 mm, respectively). We identified
the coincidence signals of the two scintillators
as the β rays. Figure 1 shows the time spectrumof β rays observed after irradiation of the
proton beam (its intensity about 50 nA) for 100
seconds. Fast and slow components of the βdecay were observed. The fitting results
assuming half-lives of 29P and 30P are shown bya solid line in Fig. 1. The β ray amounts of 29P
and 30P evaluated from the fitting results were∼0.12 cps/nA and ∼0.30 cps/nA, respectively.
Fig. 1 Time spectrum of β rays in 3 MeV proton

In the future, we will use the polarized proton

beam with a Si target. The solid line is the fitting

beam to measure the nuclear polarization of the

29

30

result assuming half-life of P and P.

produced unstable nuclei (29P, 30P and so on),and furthermore perform experiments with thetarget containing Mg to evaluate the production amount of 25Al and its nuclear polarization. If significant
nuclear polarization is observed, nuclear moment measurements for 30P and 25A1 will be carried out.
Reference[1] T. Matsumoto et al., UTTAC Annual Report 2015 (2016) 11.

11

2.2

The qualification test of sulfur targets for intense beam irradiation

S. Kimura, A. Ozawa, T. Moriguchi, H. Miyatake1 , Y. Hirayama1 , Y.X. Watanabe1 , M. Mukai, M. Oyaizu1
Nuclear masses in the vicinity of the N = Z line are crucial to determine the rapid-proton capture
process (rp-process) pathway, which drives an explosive astronomical phenomenon called type I X-ray
burst. Unfortunately, the masses of key nuclei in the rp-process have not been measured experimentally
yet with the required precision, in particular the mass evaluation of 66 Se has been highly desired.
The mass measurement of 66 Se by using the SHE-mass facility, which consists of a multireflection
time-of-flight mass spectrograph [1] coupled with a gas-filled recoil ion separator GARIS-II [2] has beenplanned. In order to produce 66 Se, a fusion-evaporation reaction 32 S(36 Ar, 2n)66 Se will be employed. A
production cross-section of 66 Se via this reaction is estimated to be ∼ 70 nb, therefore sulfur targets thatare applicable to intense 36 Ar beam irradiation are required. The MoS2 targets prepared by a spray coating
technique [3] on Ti backing foils are adopted as the sulfur targets. MoS2 has large sulfur composition ratio
and is chemically stable, but its stability to intense beam irradiation is still unclear. Thus there is a need toconfirm an irradiation tolerance of the MoS2 targets.
A 40.6 MeV 35 Cl6+ beam, with average intensity of 20 pnA, was provided by the 6 MV tandem
electrostatic accelerator at University of Tsukuba. The experimental setup in the scattering chamber of A7
course is shown in Fig. 1. A Monat S2 target on 3 µ m Ti backing foil was mounted on a target ladder. A
target thickness was 0.8 mg/cm2 . A Si detector and an 241 Am α -source were installed diagonally acrossthe target ladder.
Measurements were performed by repeating the following procedure: irradiation of the 35 Cl6+ beam
is carried out in a certain period of time and, subsequently, the thickness of Monat S2 target is measured via
an energy spectrum of α -particles fed from the 241 Am source. Figure 2 shows the measured peak energy

Peak channel ( ch. )150
Ti backing

140
130
120
110
100
0

200

400

600

800

1000

1200

Charge ( µC )Fig. 2. Peak energy shift of the α -particles.
Red dashed line shows the peak position of the
α -particles passed only through the Ti backing
foil.

Fig. 1. (a) Schematic view of the experimental
setup. (b) Photograph of the target ladder.

1 Wako Nuclear Science Center (WNSC), Institute of Particle and Nuclear Study (IPNS), High Energy Accelerator Organiza-tion (KEK), Wako 351-0198, Japan12

shift of the α -particle which passed through the Monat S2 target. In Fig. 2, no significant peak shift isobserved for the beam irradiation up to ∼ 1200 µ C; it indicates that the beam irradiation does not affectthe stability of the Monat S2 target. Total measurement time was calculated to be 3 hr and a 30 cm diameterrotating target wheel [4] will be used in the SHE-mass facility. The present test corresponds to a 28 hr
irradiation with 1 pµ A beam.
Thus we confirmed that there is no problem in the stability of MoS2 targets under the intense beamirradiation.

References[1] P. Schury et al., Nucl. Instr. Meth. Phys. Res. B 335 (2014) 39.
[2] D. Kaji et al., Nucl. Instr. Meth. Phys. Res. B 317 (2013) 311.
[3] J. P. Greene and C. J. Lister, Nucl. Instr. Meth. Phys. Res. A 480 (2002) 79.
[4] D. Kaji and K. Morimoto, Nucl. Instr. Meth. Phys. Res. A 792 (2015) 11.

13

2.3

Test experiment for the isotope analysis of sulfuric acids generated in
atmospheric air by proton irradiation

Y. Nakai 1, Y. Shiina, N. Yamamoto, K. Sasa, S. Tomita
Gas-phase particle formation following irradiation of ionizing particles is one of major processes in agas involving chemical species, such as water, sulfuric acid, volatile organic compound, which can becondensed depending on atmospheric pressure and temperature. Especially, it has been known that sulfuric
acid enhances generation of small droplets by ionizing radiation [1, 2]. In this case, sulfuric acid isconsidered to be formed mainly through an oxidation of SO2. However, the detailed mechanism of SO2oxidation by irradiation of ionizing particles has not been identified yet although some indications havebeen proposed [3].
To investigate the mechanism of SO2 oxidation, Ishino et al. [4] performed isotope analysis of oxygenand sulfur in sulfuric acid and sulfate mainly contained in nano-droplets generated in humidified gases
irradiated with a 1.8 MeV proton beam. Measured ∆17O values were roughly consistent with themechanism for SO2 oxidation suggested in previous studies [3, 5]. On the other hand, the values of ∆34S inthis study are quite different from those of already-known major reactions for atmospheric sulfate
production [3, 6]. This discrepancy has not been resolved yet. One of possible reasons is that the protons
lost all the kinetic energies and were fully stopped in the target gases. Just before being stopped in the gas,
the electronic stopping power for the protons is increased. Thus, high ion density and different proportionof excited products might induce more complex chemical reactions.
We plan to perform oxygen and sulfur isotope analysis of sulfuric acid (and sulfate) produced in
irradiation of a 12 MeV proton beam using 6 MV Pelletron tandem accelerator at UTTAC. Since 12 MeV
protons have the range of 1.57 m in the atmosphere of 1 atm, use of an irradiation chamber of 25 cm inlength allows us to avoid complexity caused by the stopping of the beam within the gas. As the first step inthis year, we performed measurements of SO2 consumptions as functions of an SO2 mixing ratio and abeam current to find suitable experimental conditions for isotope analysis of sulfuric acid. Figure 1 shows
the setup for the test experiment, which consists of a humidified sample-gas generator, an irradiationchamber, a monitor of the sample gas pressure, and a monitor of the SO2 concentration. A wet air was
generated by bubbling pure air in ultra-pure water. The sample gas was produced by mixing the wet air
with a dry air of the same purity. The total flow rate of the sample gas was maintained at 2 SLM (Standard
Liters per Minute) using mass flow controllers. A part of gas flow downstream of the irradiation chamber
was introduced to the SO2 concentration meter.
In this test experiment, we found that the SO2 consumptions increase with not only higher SO2 mixing
ratio, but also higher beam current. For high beam current, the SO2 consumptions are saturated and thesaturation beam current becomes higher for higher SO2 mixing ratio.

1

RIKEN Nishina Center

14

Fig. 1. Schematic drawing of the experimental setup.
References[1] J. H. Seinfeld and S. N. Pandis, Atmospheric Chemistry and Physics: From Air Pollution to Climate
Change (Wiley-Interscience, 2006), 2nd ed.
[2] S. Tomita et al., Nucl. Instr. Meth. Phys. Res. B 365 (2015) 616.
[3] M. B. Enghoff et al., Atmos. Chem. Phys. 12 (2012) 5319.
[4] S. Ishino et al., UTTAC Annual Reports 2014, p36 (2015).
[5] N. Bork et al., Atmos. Chem. Phys. 13 (2013) 3695.
[6] E. Harris et al., Environ. Sci. Technol. 47 (2013) 12174.

15

3.
ACCELERATOR MASS SPECTROMETRY3.1

Operation of the Tsukuba 6 MV multi-nuclide AMS system for the year
2016

K. Sasa, T. Takahashi, T. Matsunaka, S. Hosoya, M. Matsumura, H. Shen, M. Honda, Y. Ota, K. Matsuo,
A. Sakaguchi, K. Sueki
A new horizontal-type 6 MV Pelletron tandem accelerator (model 18SDH-2 Pelletron, NEC, USA) was
installed at the University of Tsukuba in March 2014 [1]. After 2 years of construction and preparation, thefirst test on multi-nuclide AMS has been performed in March 2016. The rare particle detection system on
the 6 MV Pelletron tandem accelerator (Tsukuba 6 MV multi-nuclide AMS system) was designed andconstructed for high-sensitivity detections of 10Be, 14C, 26Al, 36Cl, 41Ca, and 129I, and was also expected tomeasure other radioisotopes of 32Si and 90Sr. The background of the system for 14C measurements using
the 4+ charge state and the terminal voltage VT = 5.0 MV was reached down to 14C/12C = 2.4 ×10−16. In
addition, we successfully detected 10Be, 26Al, 36Cl, 41Ca, and 129I by the multi-nuclide AMS system in 2016.
In the case of 10Be AMS, 10BeO− was extracted from the MC-SNICS and then accelerated with VT = 6.0

10Be Std. (KNBe5-1)

10Be/Be=2.709 × 10-11

10Be3+

3000 Cycle

10B3+

Fig. 1. Two-dimensional spectrum of 10Be AMS measured with the five-anode ∆E−E gas ionization detector.

Table 1. Performance of rare particle detections by the multi-nuclide AMS system.
10

Isotopes

14

Be

26

C

6

Half-life (yr)5,730

1.36×10

Stable isotopes

9

Isobars

10

Chemical form

BeO

Graphite, CO2

Sample size (mg)0.5

0.1 - 1

Injected ion

BeO−

7.17×10

41

Cl

129

Ca

3.01×105

1.03×10

Al

37

Mg

36

Ar, 36S

41

Al2O3

AgCl

CaF2

2

1

10

C−

Al−

Cl−

CaF3

13

27

C, C

7

B

5

35

12

Be

36

Al

12

13

14

26

Li2, CH2, CH, N

Cl, Cl

40

42

5

43

1.57×1044

Ca, Ca, Ca, Ca

10 - 50 (12C-)

0.2 (27Al-)

10 (35Cl-)

0.5 (40CaF3-)

Terminal Voltage (MV)

6.0

5.0

6.0

6.0

6.0

Detected ion (Stripper)

10

3+

Be (gas)14

4+
C (gas)26

5+

Al (gas)36

8+

Cl (foil)

41

7

I

Xe

AgI
2

−

5 ( BeO )

-

127
129

K

Typical ion current (µA)

9

l

5+

Ca (foil)

Ι−
5 (

127 -

I)

5.0
129 5+

I (gas)Beam Energy (MeV)

20.3

25.0

36.0

54.0

32.5

30.0

Transmission (%)

15

40

25

10

8

10

Measure/Known (%)

80

75

70

50

90

Precision (%)

2−
0.2 (Graphite)
0.4 (CO2)

2

2

3

1

< 3 × 10−15< 2 × 10−14-16

Background (atom ratio)−15< 2 × 10

< 2 × 10

< 5 × 10

(Graphite)

-15

(CO2)

< 1 × 1016

−16

< 3 × 10−15

MV. As a result, 20.3 MeV Be3+ was detected by a five-anode ∆E−E gas ionization detector. Isobaric
interference of 10B was eliminated by an absorber cell in front of the detector. Figure 1 shows a twodimensional spectrum of 10Be AMS for a standard of 10Be/Be = 2.709 × 10−11. The background of 10Be
AMS is lower than 2 × 10−15. Table 1 summarizes the performance of rare particle detections by themulti-nuclide AMS system.
We measured 1,120 samples in total by the multi-nuclide AMS system in the period from March 2016
to March 2017. Figure 2 shows a breakdown by types of measured nuclides. Figure 3 showsmonthly-measured nuclides from March 2016 to March 2017. 129I was measured most frequently in thefiscal year 2016 in order to investigate the radiative contamination of 131I from the Fukushima Daiichi
Nuclear Power Plant accident.

Nuclides
10

Be
C
26
Al
36
Cl
41
Ca
129
I
Total
14

Be-10
1%
C-14
29%

Number
13
321
30
184
88
484
1120

I-129
43%

Al-26
3%

Ca-41
8%

Cl-36
16%

Fig. 2. Breakdown of measured nuclides by the multi-nuclide AMS system

Number of pieces

in the fiscal year 2016.

Fig. 3. Breakdown of monthly-measured nuclides by the multi-nuclide AMS
system from March 2016 to March 2017.

Reference[1] K. Sasa et al., Nucl. Instr. Meth. B 361 (2015) 124.

17

36

3.2

Cl AMS measurements with the 6 MV tandem accelerator

S. Hosoya, K. Sasa, T. Takahashi, T. Matsunaka, M. Matsumura, H. Shen, K. Sueki36

Cl (t1/2 = 3.0 × 105 yr) is a long-lived radionuclide and mainly used to determine the exposure age of

meteorites and to study the land-forming process. In addition, it has been used as an environmental tracer
in groundwater [1] and ice core studies [2]. However, 36Cl AMS measurement is interfered by an isobar
36

S. In AMS, 36Cl is separated from other ions using mass analyzing magnets and electrostatic energy

analyzer. However, the isobar 36S has the same analyzing trajectory as for 36Cl because both of them havethe same mass and energy. This causes the interference noted above. Therefore, it is necessary to separate
these isobars by the difference of energy loss in the gas ionization detector. Also, in order to achieve
highly sensitive AMS measurements sulfur contents must be minimized in sample materials. We try
several methods to reduce the influence of 36S and achieve the low-background AMS system.
The sulfur ions are mainly generated within the ion source if Cs beams irradiate the metal surface ofthe sample holder on which an AMS sample is fixed. Therefore, the amount of sulfur ion depends onmaterial and dimension of the sample holder. We
investigated the relation between various sample
holders and the amount of sulfur ion. Figure 1 shows
comparison of sulfur counts for various conditions of
two sample holders S-1 and S-2, which are made of
Cu. The diameters of the surfaces of S-1 and S-2 are
3 and 7 mm, respectively. Ta and AgBr are used asbacking materials which cover the surfaces of theholders. The results show that the smaller-sized S-1
generates larger amount of sulfur ions, probably
because the metal surface is more exposed to the Cs
beam. From this result, it is concluded that the
sample holder S-2 + AgBr backing is the mostsuitable choice for36

Cl AMS measurements.

Fig.1. Comparison of sulfur counts due to differenceswith sample holder materials. Sulfur counts
normalized with 35Cl beam current.

Probably, the reason why sulfur decreases for AgBr
backing is that sulfur is removed during thepurification process of producing AgBr.
For Cl/S isobar separation at the 6 MV terminal
voltage, we determined optimum conditions of the
five-anode gas ΔE-E detector [3], using the Monte
Carlo simulation code [4]. We also considered
chlorine charge state distribution at 6 MeV energy,
which is shown in. Fig. 2.

While Cl7+ has thehighest beam current, we selected Cl8+ because the18

Fig.2. Charge state distribution of Cl at 6 MeV.
Carbon foil of 4.8 µg/cm2 is used as a stripper foil.

spectrum separation becomes greater than for Cl7+, as will
be discussed later. Indeed, the beam current is not anTable 1. Separation ability M’ for Cl7+ andCl8+.

important factor under the present conditions of 35Cl ~ 15
− 20 µA. The Cl/S isobar separation is represented by theseparation ability M’ [3]. The values of M’ for Cl7+ and Cl8+

7+

Cl meas.
Cl8+ meas.

dE1 + dE2
1.249
1.421

dE4 + dE5
0.580
0.675

separation, listed in Table 1, clearly show better Cl/S isobar
separation for Cl8+ than for Cl7+. Figure 3 shows the histogram of 36Cl8+ obtained from the AMS
measurement. Since at dE3 the 36Cl8+ spectrum still overlaps with the 36S8+ spectrum., we gated on
2σ using dE3 signal.
After such attempts, the detection sensitivity of 36Cl/Cl reached as low as ~ 3 × 10-15. This value isthe highest performance in Japanese AMS facilities. Further refinement of the AMS system is needed toachieve higher sensitivity realized so far by several foreign facilities.

Fig.3. dE1 + dE2 vs. dE4 +dE5 spectrum after gating dE3 signal on thegas ionization detector for the sample with 36Cl/Cl ratio of 1.000 ×10-11.

References[1] Y. Tosaki et al., J. Environ. Radioact., 106 (2012) 73.
[2] K. Sasa et al., Nucl. Instr. Meth. B, 268 (2010) 1193.
[3] S. Hosoya et al., UTTAC Annual Report, 2015 (2016) 17.
[4] T. Sato et al., J. Nucl. Sci. Technol., 50 (2013) 913.

19

36

Cl/Cl and 36Cl inventory in surface soils near the Fukushima Dai-ichi
Nuclear Power Plant

3.3

Y. Ohta, K. Sueki, K. Sasa, T. Takahashi, S. Hosoya, M. Matsumura
On March 11, 2011, the Great East Japan Earthquake caused the Fukushima Dai-ichi Nuclear Power
Plant (FDNPP) accident. In consequence, a large amount of radionuclides were released into environment.
Most of the radionuclides released in this accident were from 235U in the nuclear fuels. On the other hand,radioisotopes that had their origins in coolant or nuclear reactor materials were also discharged. One ofthem is 36Cl.
36

Cl in this case is generated by 35Cl (n, γ) 36Cl, where 35Cl is contained in the coolant as impurities. At

the time of the accident, therefore, 36Cl surely existed in the coolant. However, there is one publishedarticle only which reports on the emission of 36Cl in FDNPP accident. This is probably because 36Cl inenvironmental samples can only be measured by accelerator mass spectrometry (AMS) which is usuallyinterfered with 36S, an isobar of 36Cl. For this reason, 36Cl AMS requires a lot of chemical treatments.
In Japan, there are two AMS facilities that can measure 36Cl; University of Tsukuba Tandem
Accelerator Complex (UTTAC) and Micro Analysis Laboratory, Tandem Accelerator, The University ofTokyo (MALT). Miyake et al. measured 36Cl in surface soils around FDNPP by AMS system in MALT
and relatively high 36Cl/Cl ratios were detected [1]. However, their results have large errors of ±20−59%
and only 10 samples have been measured so far. Accordingly, measurements of more samples with smaller
errors are necessary to discuss the release of 36Cl in detail.
For samples in the present study, surface soils with a thickness of 5 cm were collected at 10
locations to the northwest of FDNPP from June 12 to August 1, 2013. The sample preparation scheme wasdesigned by referring to Tamari [2], Amano [3], and Bastviken et al. [4]. The soil samples were dried at
60°C, sieved through 2 mm mesh and grinded using a mortar and pestle. The 20−40 g soil in 50 mL
centrifuge tubes were subsequently frozen at −18°C and thawed at 60°C to destruct microbial cells.
Adding 0.01 M HNO3 (3 times the amount of soil) to 50 ml centrifuge tubes, the tubes were sonicated for
3 hours, centrifuged at 2000 rpm for 15 minutes and then the supernatants were pipetted to plastic bottles.
Same extraction was repeated four times and all extracts were mixed. Activated carbon of 1−2 g wasadded to the extracts in order to remove organic sulfur and also extractable organic chlorine (Clorgex).
Meanwhile, non-extractable organic chlorine (Clorg) and chlorine in mineral (Clmin) remained in the soil. In
the extracts, only inorganic chlorine (Clinorg) existed. After shaking over 3 hours, the extracts were filteredthrough a 0.2 μm filter.

After 10 mL aliquot was transferred to plastic bottles in order to measure stablechlorine with ion chromatography, 0-200 μL carrier prepared from halite (36Cl/Cl = 3.52×10−14) was added
to a filtrates. After adding 30% H2O2 (half the amount of soil) to filtrates and standing for 3 hours becauseof organic matter decomposition, 3 M NH3 (0.15 times amount of soil) were added and stood for 3 hours
to precipitate metal impurity as hydroxide. After filtration, the filtrates were concentrated to about 10 mL
by hot plate at 80°C.
Concentrated solutions were acidified by 13 M HNO3 and excess 0.3 M AgNO3 were added. After20

centrifugation (2000 rpm, 15 minutes), supernatants were removed and precipitates were dissolved in 3 M
NH3 (2 mL). 0.05 M Na2CO3 (2 mL) and then saturated Ba(NO3)2 (1 mL) were added in the solutions andBaCO3 and BaSO4 were coprecipitated and filtered through a 0.2 μm filter. Such BaCO3 method, named
by Tamari [2], enables effective removal of SO4− by coprecipitating in [Ba2+]/[CO32-]=2.5−7.0. In thiswork, the BaCO3 method was repeated three times although only 0.05 M Na2CO3 were added at thesecond and the third time (respectively 1.4 mL and 0.9 mL) using remains of Ba2+ at the first time. After
reprecipitation of AgCl by adding 13 M HNO3 and excess 0.3 M AgNO3, AgCl were redissolved by 3 M
NH3 (2 mL) and 0.05 M Na2CO3 (2 mL) in order to remove Ba2+ as an interference element of ionization
at MC-SNICS (Multi Cathode-Source of Negative Ions by Cesium Sputtering). After filtering through a
0.2 μm filter, AgCl was reprecipitated and washed for three times with ultrapure water and twice with
99.5% C2H5OH. After drying at 110°C, the AgCl sample was used for AMS measurement of 36Cl.
Measurement results of 36Cl are summarized in Table 1. Before FDNPP accident, 36Cl/Cl ratios
varied in the range 0.09−1.14 (×10−12) and the mean value was 0.46 × 10−12 around FDNPP [5]. However,extremely higher 36Cl/Cl ratios are observed at NM-7 and NM-15. Furthermore, 36Cl inventory at NM-17
is as large as those of NM-7 and NM-15. Consequently, the release of 36Cl in FDNPP accident is evident
and influence of the accident is recognized at 3 locations as far as 8 km away from FDNPP. At otherlocations of 8-28 km from FDNPP, there was little influence of FDNPP accident. The release of 36Cl seems
noticeable only around FDNPP. Further investigation is required to discuss the details.
Table 1. Summary of 36Cl measurement results

References[1] Y. Miyake et al., Nucl. Instr. Meth. Phys. Res. B 361 (2015) 627.
[2] M. Tamari, Master’s thesis, University of Tsukuba 2009 (in Japanese).
[3] T. Amano, Master’s thesis, University of Tsukuba 2011 (in Japanese).
[4] D. Bastviken et al., Geochimica et Cosmochimica Acta 71 (2007) 3182.
[5] R. Seki et al., Nucl. Instr. Meth. Phys. Res. B 259 (2007) 486.

21

3.4

Determination of I-129 in radioactive particles by AMS

K. Matsuo, K. Sueki, T. Matsunaka, M. Matsumura, K. Sasa, T. Takahashi, S. Hosoya, A. Sakaguchi,
M. Honda, R. Inaba, Y. Satou 1
In March 2011, radioactive particles were emitted into the environment from FDNPP [1]. The
particles contain various radionuclides that were produced in nuclear reactors. In this AMS study, we
focused on 129I which is a long-lived nuclide (T1/2 = 1.57×107 years) so that its amount remains
effectively unchanged since the accident. The study of 129I should provide information about the
behavior of short-lived 131I which is also emitted at that time and is very serious for the environment.
We tried to understand how iodine was incorporated into radioactive particles by determining theamount of 129I in the particles.
The four sample particles were picked from the dust which was collected at the site 2 km away to
the north-north west from FDNPP. Iodine species were extracted from the particles after the three stepsof pretreatment of the samples, as follows.
The first step was to wash the particles by Milli-Q water. One particle with 5 mL of Milli-Q water
was put in a centrifugation tube and washed in the ultrasonic cleaner (AS ONE, US-4R) for 30 minutes
before the wash liquid was filtrated through 0.2 μm filter.
The second step was extraction by 25% tetramethylammonium hydroxide (TMAH) aqueous
solution (TAMACHEMICALS, TAMAPURE-AA). The particle after the first step was put in the vessel
for the microwave digestion apparatus (BERGHOF, speedwave4) with 5 mL of TMAH aq. After
entering the vessel into the machine, the particle was irradiated by microwaves at 90 W for 3 hours and
we took out the solution.
The third step was thermal hydrolysis using the tube furnace. The particle passed through the firstand second steps was placed on a ceramic boat. Subsequently, the boat was heated in the tube furnace inwhich moisture-containing oxygen flowed at 990°C for 30 minutes and a solution for trapping iodine
was fitted on the discharge side of the tube with an L-shaped tube at that time. This solution wascomposed of 6.1 mL of Milli-Q water, 800 μL of 25% TMAH aq. and 100 μL of 2% Na2SO3 aq. After
finished heating, the whole solution including the wash liquid of the L-shaped tube made to 10 mL.
Also, blank samples were made in all the steps.
Each of the first-, second-, and third-step samples were fractionated into a half, 1/10 and 1/100,
respectively, and NaI aq. as carrier (2 mg of I) was added to each of these samples. And then,purification of iodine, treatment of AgI, and the AMS measurements were carried out in accordancewith the condition by Matsunaka et al. [2, 3] .
The amount of 129I was determined from the result of 129I / 127I by Matsuzaki et al [4]. In thereference document, the amount of 127I in the sample was determined by ICP-MS and is consideredwhen calculating the amount of 129I. However, the density of iodine of the particles was estimated to be
1

Japan Atomic Energy Agency (JAEA)

22

under 50 ppm because iodine was undetected by the elemental analysis of BL37XU at SPring-8 [5].
Therefore, the amount of 127I in the particle was neglected since it was much smaller than that in the
carrier. The numbers of 129I per one particle was calculated by summing up second and third steps.
Finally, we obtained the activity of 129I, the number of atoms, the activity of 129I and the activity ratio of129

I / 137Cs (Bq/Bq) per one particle on March 11, 2011.
The results are shown in Tables 1 and 2. Table 1 shows the numbers of 129I atoms in the samples at

each step and Table 2 shows the numbers of 129I atoms, their activity, and 129I / 137Cs (Bq/Bq) per one
particle at the time of the occurrence of the accident. It is presumed that some amounts of 129I havecome out from the surface of particles by ultrasonic cleaning. The extraction by TMAH aq. seems to bemeaningful because 5 − 26% of the whole amounts of 129I were extracted by this step. Furthermore, theaverage of 129I / 137Cs of the four particles (2.9×10−9) is smaller than that of the sampled soil [(4.3±0.1)×10−7] by two orders of magnitude. Therefore, it is presumed that the behavior of I and Cs
absorbed into particles is different from that of singly emitted Cs and I.
Table 1. Number of 129I atoms in the samples at each step

CF-01M02

Washing by
milli-Q
5.04±0.16×107

Extraction by 25%
TMAH aq.
3.33±0.07×108 (26%)

1.24±0.06×109 (74%)

CF-01M06

6.91±0.59×106

1.64±0.05×108 (9%)

1.99±0.12×109 (91%)

CF-01M08

4.11±0.13×107

2.75±0.08×108 (23%)

9.13±0.05×108 (77%)

CF-01M15-1

1.91±0.05×108

5.83±0.30×107 (5%)

1.08±0.06×109 (95%)

Names of particles

Thermal hydrolysis

Table 2. Number of 129I atoms, their activity, and 129I / 137Cs (Bq/Bq) at the time of the accident
129

I / 137Cs (Bq/Bq)

Names of particles

Number of atoms

Activity (Bq)

CF-01M02

1.29±0.08×109

1.80±0.11×10−6

5.79±0.45×10−9

CF-01M06

1.87±0.13×109

2.61±0.18×10−6

3.64±0.32×10−9

CF-01M08

1.19±0.05×109

1.66±0.08×10−6

1.17±0.08×10−9

CF-01M15-1

1.14±0.06×109

1.60±0.08×10−6

1.03±0.06×10−9

References[1] K. Adachi et al., Sci. Rep. 3 (2013) 2554.
[2] T. Matsunaka et al., Nucl. Instr. Meth. B 361 (2015) 569.
[3] Y. Muramatsu et al., Quat. Geochronol 3 (2008) 291.
[4] H. Matsuzaki et al., Nucl. Instr. and Meth. B 123 (2007) 721.
[5] M. Suzuki et al., SPring-8 Users Info. 16 (2011) 201 (in Japanese).

23

3.5

Preparation of a 129I standard solution for ICP-MS/MS

M. Honda, K. Sasa, T. Takahashi, T. Matsunaka, S. Hosoya, M. Matsumura, K. Sueki
A large amount of 129I (physical half-life: 15.7 Myr) has been introduced into the terrestrial
environment through nuclear weapons’ tests, spent nuclear fuel reprocessing operations, and nuclear
accidents. The study of anthropogenic 129I is of increasing concern in Japan from the viewpoint of aradiation risk assessment. AMS have been commonly used for the 129I analysis, but the latest triple
quadrupole ICP-MS (ICP-MS/MS) is becoming an alternative analysis. ICP-MS/MS provides a highsample throughput and optimum way for the analysis of high-level 129I (129I/127I> 10−8 ) which is hard todeal with AMS [1]. Absolute ICP-MS/MS measurements require reliable standards for calibration. In thisfiscal year, the 129I/127I ratio of a home-made standard solution for ICP-MS/MS was evaluated with 6MV
AMS at UTTAC.
The 129I standard solution “tRIC-1” was prepared from a stored 129I solution (127I and 129I
concentrations are 1 mg/mL and 0.448 Bq/mL, respectively) with 2% tetramethyl ammonium hydroxide
solution (Tama Chemicals). The stable iodine (127I) concentration in tRIC-1 was determined by
ICP-MS/MS to be 9.95 ± 0.10 ppm. A portion of 100 mL tRIC-1 was mixed with 698 mg iodine carrier(Orion Ionplus, Thermo scientific, which has 129I/127I = 1.80 × 10-13 [2]) and then precipitated as silver
iodide (AgI). The precipitated AgI was divided into five batches and the five targets prepared from eachbatch were measured. The 129I/127I ratios were all normalized using the standard material provided by
PRIME Lab. at Purdue University (nominal value is 6.54 × 10−12). In AMS, the charge state of 5+ waschosen for the terminal voltage of 5 MV. The 129I/127I ratio in tRIC-1 was calculated from the AMS and
ICP-MS/MS results.
A good reproducibility was obtained in the 129I AMS measurements, as shown in Fig. 1. The 129I/127I
ratios of tRIC-1 range from (5.93 ± 0.16) × 10−5 to (6.40± 0.05) × 10−5. The 129I/127I ratio is evaluated as
the averaged value for the five batches, i.e., (6.20 ± 0.18) ×10−5.

Fig. 1. 129I/127I ratios in a home-made standard solution.
References[1] T. Ohno andY. Muramatsu, J. Anal. At. Spectrom. 29 (2014) 347.
[2] H. Matsuzaki et al., Nucl. Instr. Meth. B 259 (2007) 721.

24

3.6

Performance evaluation of the AMS-measurement of iodine-129 by the
6 MV tandem accelerator at University of Tsukuba

M. Matsumura, K. Sasa, T. Matsunaka, T. Takahashi, S. Hosoya, Y. Satou 1 , K. Sueki
A multi-nuclide AMS system for 10Be, 14C, 26Al, 36Cl, 41Ca, and 129I is now available at UTTAC [e.g.,1, 2]. This report focuses on the performance of 129I measurement for near-future development of thestandard reference materials of 129I. The 129I measurement conditions of the accelerator were as follows;
injected ion species of I− , the terminal voltage of 5.0 MV, and the analyzed ions of 30MeV I5+. Isobutane
gas of 19 Torr was used for the gas-ionization detector with an entrance window of a 1.5-µm thickpolyester film. The 129I standard reference materials, Z94-0596 and Z94-0597, named Purdue1 and Purdue
2, respectively, were provided by PRIME Lab., Purdue University [3, 4].
The ratios of 129I/127I were measured in the experiments. The measured ratio for Purdue 1 is (8.29 ±0.08) × 10−12 against the consensus ratio of 8.38 × 10−12 with a precision error of 1.1% , while for Purdue 2
the measured ratio is (6.54 ± 0.03) × 10−11 against the consensus ratio of 6.54 × 10−11 with a precision errorof 0.5%. These results thus indicate good agreement, including the precision errors,

between themeasured and consensus values. Figure 1 shows consistency between the two values, which demonstrates
that the present experimental setup and the method of analysis are reasonable.

Fig. 1. Comparison between the measured and the consensus ratios of 129I/127I
for the 129I standard reference materials.

Figure 2 shows dependence of the beam current and transmission of 129I on the mixing ratio of the
Nb-powder to the target AgI of Purdue 2. We see that the maximum beam current, i.e., the optimum
mixing ratio is given at Nb:AgI＝4：1, as is generally proposed. Figure 3 shows the results of blank
1

Japan Atomic Energy Agency

25

measurements. ”Old Iodine” provided from DeepWater corporation has the extremely low backgroundlevel of the 129I/127I ratio as low as 1 × 10−14. Therefore, the machine background is estimated to be as low
as on the order of 10−15 in the value of 129I/127I.
This work was supported by JSPS KAKENHI Grant Number 15H02340.

Fig. 2. Dependence of beam current and transmission of
129
I standard reference materials on the Nb/AgI mixing
ratio.

Fig. 3. Measured 129I/127I ratios for various
blanks.

References[1] K. Sasa et al., Nucl. Instr. Meth. Phys. Res. B 361 (2015) 124.
[2] S. Hosoya et al., Nucl. Instr. Meth. Phys. Res. B (2017) in press.
[3] P. Sharma, et al., Nucl. Instr. Meth. Phys. Res. B 123 (1997) 347.
[4] H. Matsuzaki, et al., Nucl. Instr. Meth. Phys. Res. B 361 (2015) 63.

26

3.7

Reconstruction of temporal variation for anthropogenic radionuclides
in the Japan Sea using a coral core sample

R. Inaba, A. Sakaguchi, T. Nomura1, H. Yamano H2, K. Sasaki K3, T. Watanabe4, M. Honda, K. Sasa,
T. Matsunaka, S. Hosoya, T. Takahashi, M. Matsumura, K. Sueki
Due to recent improvements in instrumentation and chemical pretreatments, Iodine-129 (129I ；T1/2=1.57×107 y) is increasingly being used as an oceanic circulation tracer instead of the short half-life
artificial nuclide, 137Cs. 129I is a long-lived anthropogenic radionuclide that is introduced to the earth
surface environment, mainly by atmospheric nuclear tests and/or nuclear-related facilities. However, 129I
input history to “the miniature ocean”, the Japan Sea, has not been clarified. In this study, the input historyof 129I to the surface water of the Japan Sea has been reconstructed through measurement of 129I/127I atom
ratios in a coral sample collected from Iki Island; the main entrance of surface water to the Japan Sea.
The coral core sample (Dipsastraea speciosa) was collected in November 2012 from a depth of 3 m at
Kurosaki, Iki Island (N33o 48'22.5, E129 o 40'02.9). The annual growth bands were confirmed by X-ray
imaging and Sr/Ca analysis with laser ablation (LA)-ICP-MS for coral slabs, and the coral sections were
cut into annual segments in accordance with the X-ray image and the variation of the Sr/Ca ratios. The
129 127

I/ I in each annual ring was measured by AMS after appropriate sample preparation.
The 129I/127I atom ratios were reconstructed over a wide range of (0.145−71.3)×10−12. It was observedthat the ratio drastically increased in theearly1950s, and has high values even now.
It may be presumed that airborne 129I,
which is released from nuclear-related
facilities, has been constantly absorbed by
the surface seawater around this area. The
recent atom ratios found in the surface
water of the Japan Sea are higher than
those

of

Guam

[1],

Baler

in

the

Philippines [2]. It was also observed thatthe reconstructed 129I/127I atom ratios show
different variations than for

236

238

U/ U

ratios that were constructed from the samecoral core sample [3].

Year
Fig.1. Variations of 129I/127I atom ratios reconstructed from theannual rings in the coral cores from Guam [2], Baler [1] andIki Island (this study).

References[1] C. Chang et al., J. Environ. Radioact. 165 (2016) 144.
[2] A. T. Bautisata et al., J. Environ. Radioact. 164 (2016) 174.
[3] A. Sakaguchi et al., J. Geophys. Res. Oceans 121 (2016) 4.
1

Graduate School of Science, Hiroshima University
National Institute for Environmental Studies
3 Kanazawa Gakuin University
4 Faculty of Science, Hokkaido University
2

27

3.8

Radiocarbon variations since 1960 in tree rings near the Tokai nuclear
facilities in Japan

T. Matsunaka, K. Sasa, T. Takahashi, S. Hosoya, M. Matsumura, K. Sueki, Y. Satou 1
Tokai area in Ibaraki Prefecture is located 1.8 km south-southwest of the Tokai Nuclear Power Plants(Tokai NPP and Tokai-2 NPP) and 1.4 km North-Northwest of the Tokai Reprocessing Plant (Tokai RP).
To evaluate the environmental impact of the atmospheric 14C discharge from the Tokai nuclear facilities, a80-year-old pine tree grown at Tokai area was cored and 14C in each annual ring was measured using the
AMS system at UTTAC. The terminal voltage of 5.0 MV and the charge state of 4+ were chosen for
acceleration and detection of 14C. The measurement error of the system was ±0.3% for NIST-4990C(HOx-II), and the blank levels were 0.04–0.09 pMC (55,950–63,300 yrBP) for IAEA-C1 (Marble). The
14

C specific activities varied from 232.8 Bq kg−1 C to 403.3Bq kg−1 C in the tree rings formed during theperiod 1959–2013. The specific activities in 1967–2010 are significantly elevated compared with theambient background values, clearly indicating 14C discharges from the Tokai nuclear facilities during theirnormal operation. The excess 14C activities of 0.48–70 Bq kg−1 C in 1965–2011, shown in Fig.1, arepositively correlated with the estimated annual 14C discharges of 0.02–2.0 TBq from Tokai NPP(operational period: 1966–1997), Tokai-2 NPP (operational period: 1978–2010) and Tokai RP (operational
period: 1977–2007) with R2 of 0.72 (n = 38), as shown in Fig.2. These activity values of < 70.0 Bq kg−1 C
are corresponding to an additional annual effective dose of < 3.9 µSv via the food ingestion pathway in thelocation studied.

Fig. 1. Red circles: the variations of excess 14C activity in the Tokai tree rings. White circles: estimated annual 14C
discharge from Tokai NPP, Tokai-2 NPP, and Tokai RP [1], calculated by multiplying the 14C emission factors for NPP[5.5 TBq W−1 for Magnox GCR (Tokai NPP) and 0.51 TBq W−1 for BWR (Tokai-2 NPP) ] [2, 3] by the annual
electrical energy output [4].
1Collaborative Laboratories for Advanced Decommissioning Science, JAEA

28

Fig. 2. The correlation between excess 14C activity in the Tokai tree rings and estimated annual 14C
discharge from Tokai NPP, Tokai-2 NPP, and Tokai RP. The linear regression line and coefficient ofdetermination (R2) are shown in the correlation diagram.

References[1] J. Koarashi et al., J. Nucl. Sci. Technol. 53 (2016) 546.
[2] UNSCEAR, Exposures to the Public from Man-made Sources of Radiation, vol. 1 (2000).
[3] H. D. Graven and N. Gruber, Atmos. Chem. Phys. 11 (2011) 12339.
[4] IAEA (2016), http://www.iaea.org/PRIS/CountryStatistics/CountryStatisticsLandingPage.aspx.

29

3.9

Trial of determination of 41Ca concentration in iron meteorites byaccelerator mass spectrometry

Y. Oura 1, N. Kuroiwa1, M. Matsumura, S. Hosoya, T. Takahashi, K. Sasa
Cosmogenic radionuclides 36Cl and 41Ca are found in meteorites, which are produced by several
nuclear reactions such as proton and secondary-neutron induced spallation reactions and neutron capture
reactions. To study irradiation histories of meteorites, accelerator mass spectrometry (AMS) for both of
the two radionuclides is required. However, the former AMS system at UTTAC allowed measurements of
only 36Cl concentrations [1]. In 2016, UTTAC started operation of the new AMS system for measurementsof several radionuclides including 41Ca. We therefore tried to determine 41Ca concentration in ironmeteorites by applying the new AMS system.
Using a radiotracer, a chemical separation procedure for Ca in iron meteorites was evaluated especiallyfor a pH condition in separation of Ca from Fe. The evaluation procedure was applied to two ironmeteorites, Gibeon and Campo del Cielo meteorites, in which 36Cl concentrations were determined by theformer AMS system at UTTAC [1]. Each piece of about 1 g was cut out from the same fragment forprevious 36Cl determination. After dissolution in HNO3 with Ca and Cl carriers (about 4 mg each), AgNO3
was added to precipitate AgCl. Ammonia water was added to the supernatant solution to make pH 5.4− 5.8, and then Fe(OH)3 was precipitated. Then, CaC2O4 was precipitated by adding (NH4)2C2O4 in the
supernatant solution followed by dissolution of CaC2O4 in 6 mol/L HCl. Remained trace of Fe in thissolution was removed by anion exchange method, and then CaF2 was finally obtained by adding HF to theeluate containing Ca. The AgCl was purified in several steps. Final Ca and Cl fractions were divided into
halves, and both half portions were subjected to AMS measurement independently.
In AMS with the terminal voltage of thetandem accelerator set to 6 MV, 41Ca7+ and 40Ca7+
in 41Ca standard samples were measured for about3000 sec (10×300 sec) by a gas ionization detector
and a Faraday cup, respectively. The calibration
curve obtained, shown in Fig. 1, demonstrates
good correlation between 41Ca/40Ca count ratio andcertified 41Ca/Ca atomic ratio. According to thecalibration curve, down to about 0.5×10−13 of
41

Ca/Ca are found to be detectable at least under

the condition in this study. The results for ironmeteorites are tabulated in Table 1. For Campo delCielo meteorite, in which 36Cl concentration isFig. 1. Calibration curve for 41Ca obtained by

2.38 ± 0.01 dpm/kg [1], 30 − 50 counts of 41Ca

1

measurement of 41Ca standard samples.

Tokyo Metropolitan University

30was observed. Although the observed count of 41K was larger than that of 41Ca, 41Ca was sufficiently
discriminated from 41K on the two-dimensional spectra. Concentrations of 41Ca for two portions of Campodel Cielo are consistent within their uncertainties. Content of 41Ca was estimated based on the combinationof the determined 36Cl concentration and a model calculation by Ammon et al. [2]. The determined 41Ca
concentrations in Campo del Cielo were in agreement with a range of estimated concentration, whichassures the accuracy of the present 41Ca determination. On the contrary, 41Ca concentration determined for
Gibeon meteorite, in which 36Cl concentration determined is 0.019 ± 0.001 dpm/kg [1], is about 10 times
larger than the estimated concentration. According to the calibration curve, no count of 41Ca is estimated tobe observed for the estimated 41Ca concentration. Thus the observed 41Ca of 2 counts is probably due to41

K. For 1 g of iron meteorite and 2 mg of Ca carrier, the concentration down to about 0.02 dpm/kg isfound to be detectable.

GibeonCampodel Cielo

A
B
A
B

Measurement
time [s]
2650
2469
2441
2072

Table 1. Results for iron meteorites.
41
Count Atomic 41Ca/Ca
Ca
41
-12
of Ca
[×10 ][dpm/kg]2
0.57
0.38 ± 0.30
047
4.5
3.9 ± 0.632
3.4
2.9 ± 0.6

References[1] Y. Oura et al., UTTAC Annual Report 2010 (2012) 42.
[2] K. Ammon et al., Meteoritics and Planetary Science 44 (2009) 485.

31

Estimated 41Ca Count[dpm/kg]of 41K
0.020 - 0.046
337
287
2.6 - 5.8
350
95

4.
BEAM AND ISOTOPE APPLICATIONS

4.1

Probing the effect of point defects on the leakage blocking capability of
Al0.1Ga0.9N/Si structures using a monoenergetic positron beam

A. Uedono, M. Zhao1, E. Simoen1,2
Vacancy-type defects in Al0.1Ga0.9N were probed using a monoenergetic positron beam. Al0.1Ga0.9N
layers with different carbon doping concentrations ([C] = 5 × 1017−8 × 1019 cm−3) were grown on Si
substrates by metalorganic vapor phase epitaxy. The major defect species in Al0.1Ga0.9N was determined to
be a cation vacancy (or cation vacancies) coupled with nitrogen vacancies and/or with carbon atoms at
nitrogen sites (CNs). The charge state of the vacancies was positive because of the electron transfer fromthe defects to CN-related acceptors. The defect charge state was changed from positive to neutral when thesample was illuminated with photon energy above 1.8 eV, and this energy range agreed with yellow andblue luminescence. For the sample with high [C], the charge transition of the vacancies under illumination
was found to be suppressed, which was attributed to the trapping of emitted electrons by CN-related
acceptors. With increasing [C], the breakdown voltage under the reverse bias condition increased. Thiswas explained by the trapping of the injected electrons by the positively charged vacancies and CN-related
acceptors. Results are shown in the following Figs. 1-8 [1].

Fig. 1. Current density J and reverse bias voltage
VR characteristics for Al0.1Ga0.9N with different
carbon concentrations ([C] = 5 × 1017−8 × 1019cm−3).

1
2

Fig. 2. Relationship between ln(J/Evf) and Evf1/2
for Al0.1Ga0.9N with [C] = 5 × 1017−8 × 1019 cm−3.

Imec, Leuven, Belgium
Ghent University, Ghent, Belgium

32

Fig. 3. S parameters as a function of incident
positron energy E for Al0.1Ga0.9N with [C] =5 × 1017 cm−3. The measurement was done in
the dark and under illumination of He-Cd
laser light. The inset shows the layer
structure of the sample.

Fig. 5. Relationship between the S value and thephoton energy for Al0.1Ga0.9N with [C] = 5 ×1017 cm−3. During the measurement, the value of
E was set to 10 keV. The PL spectrum obtainedat room temperature is also shown.

Fig. 7. Distributions of the positron density
around (a) CN and (b) (CN)4. Green, gray, andbrown circles correspond to Ga, N, and C,
respectively. The positron density increases
following the color scale as “green → yellow→ red”.

Fig. 4. Relationship between S and W corresponding to thepositron annihilation in Al0.1Ga0.9N measured with andwithout He-Cd laser illumination. The values of [C] in
Al0.1Ga0.9N are shown in the figure. The result for HVPE-GaN
is also shown. The simulated (S,W) values corresponding to
the annihilation of positrons in the delocalized state (DF) andthose of positrons trapped by vacancy-type defects in GaN are
also shown in the same figure.

Fig. 6. (a) FWHM values of Al0.1Ga0.9N (002) and (102)
peaks obtained from XRD ω-rocking curves, (b) the
breakdown voltage under reverse bias, VBD(R), and (c)the S values at E = 10 keV as a function of [C].

Fig. 8. (a) Planar averaged positron densities forCN, (CN)4, and DF-GaN. The differences between
the positron densities for CN-related defects and
DF-GaN, Δρ+, are shown in (b), where the resultsfor VGa (multiplied by 1/10) is also shown.

Reference[1] A. Uedono et al., J. Appl. Phys. 120 (2016) 215702 (1-7).

33

4.2

Study of cathode shape effect on the reliability of ∆E-E telescope ERDA

I. Harayama, Y. Hirose 1, H. Matsuzaki 2, D. Sekiba
The partial replacement of anions in metal oxides has been studied intensively. The continuous
control of anion composition, such as the ratio of O/N, enables us to tailor their optical, electronic andstructural properties. For these studies, we developed a beam line for ∆E-E telescope ERDA (elastic recoil
detection analysis) to determine the compositional ratio of O/N [1]. The developed beam line worked well
to study amorphous ZnOxNy films [2] and epitaxial CoOxNy films [3]. Our ∆E-E telescope ERDA consistsof a gas ionization chamber, which measures the energy loss of recoiling particles passing through the P10gas, and a solid state detector (SSD) for measuring their residual energies. The gas ionization chamber has
the anode, the Frisch grid and the U-shaped cathode, see Fig. 1 (a), designed by referring to the literatureon accelerator mass spectrometry [4]. In this work, we investigated influence of inhomogeneous electricfield due to the U-shaped cathode on the reliability of ∆E-E telescope ERDA.
Ideally, a gas ionization chamber collects all the electrons from the generated ion-electron pairs byapplying the sufficient electric field between the cathode and the Frisch grid. However, either weak or too
strong electric field can often cause a counting loss of the electrons. This is because the former allows therecombination of the ion-electron pairs, while the latter induces the capture of electrons by the Frisch grid.
Figures 1 (a) and (b) show the electrostatic potentials calculated by SIMION. We see in Fig. 1 (a) that theelectric field is very weak at the position (B), while it is very strong at the position (C). These
heterogeneities of the electric field by the U-shaped cathode might lead to ambiguities of the signal
intensity.
To estimate the influence of the cathode shape on the experiments, we adopted the SrTiO3 thickfilm as a reference sample for ∆E-E telescope ERDA. The target was irradiated with probe ions of 38.4
MeV 35Cl7+. The incident angle of the ions was 75° from the surface normal of the target. The recoil angle
was 30° from the incident direction of the ions. Figures 2 (a) and (b) show the two-dimensional ERDA
histograms taken by the gas ionization chamber with the U-shaped and the planar cathodes, respectively.
From Figs. 2 (a) and (b), we see that the ∆E intensities of the O and Cl curves measured using the
U-shaped cathode are 20% lower than those measured using the planar cathode. In both measurements, theexperimental conditions such as the P10 gas pressure and the applied voltages to the electrodes were thesame. This result implies that the electrons were partly lost with the U-shaped cathode.
Subsequently, we investigated how such an electron loss affects the quantitative analysis ofelemental compositions. If this phenomenon significantly causes the counting loss of the recoiling or
scattered particles, a major change in the design of the apparatus is necessary. Figure 3 shows energy
spectra of the recoiling O, which is reproduced from Figs. 2 (a) and (b). The data were taken under thesame beam dose. In Fig. 3, we see no significant difference between the two spectra within the statisticaluncertainty. This implies that the lower ∆E for the U-shaped cathode does not result from the counting
1
2

Graduate School of Science, The University of Tokyo
School of Engineering, The University of Tokyo34

loss of electrons, but probably from the complicated orbitals of electrons induced by the inhomogeneouselectric field.
In conclusion, the two types of cathode can be used safely so that we reconfirmed the validity ofthe data previously taken with the U-shaped cathode [2, 3]. However, we should use the planar cathode toremove the ambiguity in the experimental and analytical procedures.

Fig. 1. Calculated electrostatic potentials in the gas ionization chambers with (a) the U-shaped
cathode, and (b) the planar cathode. The red lines indicate equipotential lines with an interval of 5V.

Fig. 2. Two-dimensional ERDA histograms taken by the gas
ionization chamber with (a) the U-shaped cathode, and (b)the planar cathode. The target is the SrTiO3 thick film.

Fig. 3. Energy spectra of recoiling O,
reproduced from Fig. 2. The blue
and red lines indicate the data takenby the U-shaped cathode and theplanar cathode, respectively.

References[1] I. Harayama et al., Nucl. Instr. Meth. Phys. Res. B 384 (2016) 61.
[2] T. Yamazaki et al., Appl. Phys. Lett. 109 (2016) 262101.
[3] J. Takahashi et al., Appl. Phys. Lett. 107 (2015) 231906.
[4] H. Matsuzaki et al., Nucl. Instr. Meth. Phys. Res. B 172 (2000) 218.

35

4.3

Trial production of preamplifier for multi-channel SSD

K. Tsujita, Y. Sugisawa, I. Harayama, Y. Watahiki, D. Sekiba
Recently we developed a high-resolution elastic recoil detection analysis (HERDA) system at D-course
in 1MV Tandetron accelerator at UTTAC, similar to that made by Kimura’s group [1], and determined thedetection limit of the system for hydrogen using hydrogenated amorphous carbon films (a-C:H) on Si
wafers [2]. The detection limit obtained was ~3.8×1020 atoms/cm3 in a bulk, while ~1.2×1013 atoms/cm2 at
an interface. These values are not sensitive enough to investigate hydrogens at an interface between, forexample, Si and Si oxides. We have therefore tried to improve the sensitivity of hydrogen detection in thinfilms or interfaces between semiconductors and their oxides.
The detection limit of such an apparatus is determined by the signal to noise ratio. In our HERDA
system, the noises stem mainly from the dark current in the position sensitive detector (PSD) composed of
micro-channel plate (MCP) and from the stray particles scattered from the vacuum chamber walls. To
distinguish the recoiling hydrogen from the stray particle, we have tried to use PSD composed of solidstate detectors (SSD). We used a strip-type passivated implanted planar Si (PIPS) detector with sixteen
channels provided by CANBERRA Industries. The width of the one pad of the strip is ~4 mm, so that the
total dimension of the detector is ~75 mm.

Fig.1. (a) The circuit used in the present work, which is based on Ref. [3]. Some trivial
pass-condensers are removed from the schematics. (b) Inside of the trial product. (c) External
appearance of the trial preamplifier.
In the current HERDA system, the position signal generated from PSD is inherently the energy signalof the detected particles. By detecting the position and energy signals simultaneously, we can pick up only
proper position signals that are in coincidence with the energy signals in a reasonable energy range. To
operate this system, we need sixteen preamplifiers. For convenience for the future extension to theincreased number of channels, we have manufactured a simple preamplifier by referring to a literature [3].

36The test of the trial preamplifier shown in Fig. 1 was performed at D-course of 1 MV Tandetron. The
target was an a-C:H film of ~200 nm thickness deposited on the Si(100) substrate by chemical vapor
deposition (CVD). The hydrogen concentration in the film was determined as ~23 at% from theconventional ERDA carried out in the same D-course. The probe beam of 1 MeV 16O+ was shaped to 1
mm × 1 mm by a double slit system. The typical beam current was 10 nA. One of the sixteen channels,
called “ch4”, around the center of the strip detector was connected to the trial preamplifier and linear
amplifier, and other channels were floated. We put a slit-like musk to work “ch4” only. The analyzer
magnet for HERDA was fixed at 274 mT to observe the hydrogens recoiling near the sample surface. In
this case, the recoil energy is 166 keV. The bias voltage of 20 V was used for the strip PIPS as well as thenormal PIPS.

Fig. 2. The signal of recoiling hydrogen detected at “ch4” with the trial preamplifier. The
notation “N” is the scale of the linear feed-through to adjust the position of detector. The“Main Gain” signifies the coarse gain of the linear amplifier which follows the preamplifier.
The observed signal is shown in Fig. 2. We see a single peak centered at 166 keV. Even though theenergies of the recoiling hydrogen are much smaller than that typically measured with SSD, the peak canbe separated from the electrical noises, which allows signal-processing, e.g., by an analog-digital converter.
With this preamplifier, we can remove the signals from stray particles, which apparently have too-high or
too-low energies (not clearly seen in Fig. 2, but they surely exist). In future works, we will intend to makea lower-noise preamplifier, which can be used for a probe beam of 500 keV 16O+, and a compact NIM
standard module packaging sixteen preamplifiers.
References[1] K. Kimura et al., Nucl. Instrum. Meth. B 140 (1998) 397.
[2] D. Sekiba et al. , Nucl. Instrum. Meth. B 401 (2017) 29.
[3] Y. Hosono et al., Nucl. Instrum. Meth. A 361 (1995) 554.

37

4.4

Micro-PIXE analyses of pyrite in sea-floor sediments

M. Kurosawa, K. Hattori, K. Ikehata, K. Sasa, S. Ishii
Pyrite (FeS2) is a ubiquitous mineral in most hydrothermal ore deposits and can contain high level oftrace elements depending on the formation conditions [1-5]. Thus, the trace-element contents have beenfrequently analyzed to elucidate formation processes of hydrothermal ore deposits and to use for ore
exploration [1, 2, 4, 5]. The trace-element analyses have been usually performed by employing electronprobe micro analysis (EPMA), particle-induced X-ray emission (PIXE) analysis, and laser-ablationinductively-coupled plasma mass spectrometry (LA‒ICP‒MS) [1, 2, 4, 5]. In these methods, PIXE has
been often used because of the highly-sensitive, non-destructive feature and its potential for trace-element
mappings [1, 2, 4]. The common PIXE analyses in geology have focused on only trace heavy-metalelements, while the major components, sulfur and iron, have been paid less attention due to the use ofabsorbers which selectively absorb intense X-rays from Fe and S [1, 2, 4]. Lattice imperfections ordeviation from stoichiometry in pyrite, however, may provide useful information on hydrothermal
conditions of the pyrite formation. Thus, simultaneous multi-element PIXE analyses of major to traceelements, reported here, seem to be desirable for studies on chemistries of pyrite. In such a case, intense
X-ray peaks of S and Fe, the pile-up and escape peaks possibly cause undesirable influence on the othertrace-element detections and the detection limits.
Pyrite crystals were collected from drilling core samples of thick sea-floor clay sediments near an
active hydrothermal field at Iheya-North-Knoll in the Okinawa Trough back-arc basin, Japan [6]. The
sediments consist mainly of clay minerals including Mg, Na, K, and Ca and contain small amounts ofsecondary minerals formed by the hydrothermal activities; sphalerite (ZnS), galena (PbS), chalcopyrite(CuFeS2), pyrite, gypsum (CaSO4·2H2O), anhydrite (CaSO4), and barite (BaSO4) [6]. The present pyrite
samples are a few millimeter-sized and cubic-shaped crystals with no visible inclusions of their secondary
minerals. The sample surfaces were polished and coated with a carbon film to prevent electrostatic
charging.
PIXE analyses were performed using 1MV Tandetron at UTTAC. A 0.1-0.3 nA beam of 1.92-MeV
protons was focused to a spot size ranging from 26 × 26 μm2 to 33 × 36 μm2 on the sample using slits andmagnetic lenses. The incident beam was normal to the sample surface, and the X-ray measurement
take-off angle was 45˚ [7]. The characteristic X-rays excited by the incident beam were measured with theSi(Li) X-ray-energy detector (Sirius 30+ detector; e2V Scientific Instruments, UK) with a nominal
resolution of 137 eV at 5.9 keV. A 55-μm-thick Mylar film was used to attenuate the intense X-rays fromthe predominant light elements and to prevent the entry into the detector of protons scattered from thesamples. The total charge was determined by integrating the target currents, and all samples were analyzed
to the total charges of 0.05−0.25 μC. Analytical points were chosen based on optical viewing using a CCD
camera mounted on the microscope. Quantification of the PIXE analyses was performed based on themodel of Kurosawa et al. [7]. Secondary fluorescence effect was corrected by the method of Reuter et al.
[8]. The corrected amounts for most of the elements were less than a few %.

38

PIXE spectra of the pyrite samples consist mainly of intense K X-ray peaks from S and Fe, and theirpile-up and escape peaks, as shown in Fig. 1. There are no significant peak-overlaps between them and L
X-ray peaks from important impurities (Ag, Cd, In, Sn, and Sb) in pyrite. Element contents of S and Fe,
determined from PIXE, are 46.53‒44.57 and 51.45‒55.45 wt.%, respectively. This corresponds to their
atomic ratios of about 2.00:1.00 (S:Fe), indicating that

10 7 Sthe hydrothermal activities (<500 °C) do not affect theFeFe

stoichiometry of pyrite.

10hydrothermal fluids, shows no peaks of metal
impurities (Fig. 1, upper spectrum), while fertile-type
pyrite, affected by metal-rich hydro-thermal fluids,
shows K X-ray peaks from Mn, Cu, Zn, Ga, and As
and L X-ray peaks from Ag, Sb, and Pb (Fig. 1, lower

Intensity (cts)

A barren-type pyrite, less affected by metal-rich

6

ep1
e2

10 5

p1

Ag

10 3

Cu
Mn

Sb

10 2

Zn+p1 As+Pb

depths, the depth above which 99% of the observed
X-rays of an element originate at PIXE analyses,
shown in Fig. 2, are deeper than those of EPMA. The
depthsareclosely

associated

with

an

X-ray

self-absorption by sample matrix, thus they depend on

18

peaks also may affect the lower detection limits oftrace elements in pyrite. In common PIXE analyses,
the detection limits for light elements increase withdecreasing atomic numbers because of rise of the
X-ray absorption coefficients, while those for heavy
elements increase with increasing atomic numbers
because of decline of ionization cross sections by theincident proton [7]. As a result, the relationshipbetween detection limits and atomic numbers tends todemonstrate a smooth U-shaped curve [7].
The present relationship, however, is a modified

39

X-ray generation depth (μm)

major elements in a sample matrix.
the intense major peaks and their pile-up and escape

14Fig. 1. PIXE spectra of pyrite in sea-floor sediments;
the upper spectrum for barren-type pyrite, while thelower spectrum for fertile-type pyrite associated withmetal-rich hydrothermal fluids. Escape and pile-up
peaks are identified as follows: ep1 (pile-up peak of S
Kα+escape peak of Fe Kα), e2 (escape peak of FeKβ), p1 (pile-up peak of S Kα+Fe Kα), p2 (pile-up
peak of S Kα+Fe Kβ), p3 (pile-up peak of Fe Kα+Fe
Kα), and p4 (pile-up peak of Fe Kα+Fe Kβ).

the atomic number and on X-ray absorption edges of
The self-absorption and the disturbances due to

As

4
6
8
10 12
X-ray energy (keV)

For the fertile-type pyrite, it is important toburied in pyrite matrix. In fact, X-ray generation

Ga

Cr+e2

2

hydrothermal ore deposits.
consider a possibility of invisible solid inclusions

p4

10 4

spectrum). Thus, these metal impurities in pyrite may
be a clue to geochemical exploration of sea-floor

p3

p2

Fe

As
Pb

Cu
14

10

S

Sb
Sn
In
Cd
Ag

6

2

K X-ray20

L X-ray

40
60
Atomic number

80

Fig. 2. Representative X-ray generation depthsof the present PIXE analyses.

U-shaped curve as a result of the enhanced detection
X-rays, transition metal elements with atomic
numbers of 21‒27 exhibit relatively high detection
limits affected by tails and overlaps of intense
pile-up and escape peaks of S and Fe. For L X-rays,
platinum group elements with atomic numbers of
44‒46 display extremely high detection limits
affected by X-ray absorption at an absorption edgeof S. The enhanced detection limits for elements

1000
Detection limit (wt.ppm)

limits for several elements, as shown in Fig. 3. For K

100
L X-ray
10

with atomic numbers of 55‒71 (Cs, Ba, and REEs)

20 30 40 50 60 70 80 90
Atomic number

and 72‒80 (e.g., Hf, Ta, and Au) are due tointerferences by intense escape and pile-up peaks ofFe.
In summary, the present PIXE analyses
demonstrate that the analytical condition using a

K X-ray

Fig. 3. Detection limits of the present PIXE
analyses of pyrite with an integrated charge of 0.25
C. Circles and squares indicate detection limits formeasurements of K and L X-rays, respectively.

Mylar filter is effective for sensitive detections of important impurities with atomic numbers of 47‒51 (Ag,Cd, In, Sn, and Sb) in pyrite. The analytical condition is also useful to determine precisely sulfur contents
required to investigate the stoichiometry of pyrite. In addition, use of an Al filter would be suitable toimprove the detection limits for the other elements affected by intense S and Fe and the pile-up peaks.
References[1] D. Huston et al., Econ. Geol. 90 (1995) 1167.
[2] T. Oberthür et al., Can. Mineral. 35 (1997) 597.
[3] P. Abraitis et al., Int. J. Miner. Process 74 (2004) 41.
[4] A. Agangi et al., Nucl. Instr. and Meth. B348 (2015) 302.
[5] M. Keith et al., Ore Geol. Rev. 72 (2016) 728.
[6] Y. Miyoshi et al., Resour. Geol. 65 (2015) 346.
[7] M. Kurosawa et al., Nucl. Instr. and Meth. B266 (2008) 3633.
[8] W. Reuter et al., J. Appl. Phys. 46 (1975) 3194.

40

4.5

Mössbauer effect of CuFe2O4 spinel fine particles under external
magnetic field

H. Latiff, M. Kishimoto, S. Sharmin, H. Yanagihara, E. Kita
One of the recent approaches for enhancing magnetic anisotropy of spinel ferrites is the symmetry
reduction using lattice distortion. We have observed extraordinarily large PMA (Perpendicular Magnetic
Anisotropy) in epitaxially strained Co ferrite (CFO) (001) thin films with Ku exceeding 10 Merg/cm3 byintroducing a tetragonal distortion (c/a<1) in the structure [1, 2], where the lattice distortion results fromthe lattice mismatch between the substrate (MgO) and the deposited film (CFO). For an application of thisapproach to the practical bulk production of permanent magnets, development of the material in the formof nanoparticles is required, and a feasible method of introducing lattice distortion to nanoparticles is
crucial. We proposed the introduction of lattice distortion via the Jahn-Teller (JT) effect of Cu2+ ions incopper substituted Fe3O4 particles. We prepared cubic and tetragonal CuFe2O4 particles and analyzed the
crystal structures along with the magnetic properties. Here, we report on the applied field Mössbauer
spectroscopy performed to analyze the site distribution of the Fe3+ cations in the respective sites.
CuFe2O4 particles were synthesized by coprecipitation and flux methods. Aqueous solutions containing
Cu2+ and Fe3+ were mixed with NaOH aqueous solution to form precipitates. The precipitates were mixed
with KBr flux, and heated at 850℃ for 3 hours. The particles were then rinsed with water to remove theflux. Finally, the particles were annealed at 900°C for 2 hours in air. The XRD patterns of the as-fluxedand heat-treated samples are shown in Fig. 1 (top) and (bottom), respectively. For the as-fluxed particles
most of the peaks are of cubic spinel with a slight trace of peaks attributable to CuO. When the as-fluxed
particles were heated to 900°C in air, splitted peaks were observed showing the tetragonal spinel phase of
CuFe2O4.
Zero-field and 5T applied-field 57Fe Mössbauer spectra of the tetragonal CuFe2O4 sample wererecorded at room temperature as shown in Fig. 2. The spectra were fitted using the program MossWinn4.0
and the fitting parameters are listed in Table 1. The zero-field (0 T) spectrum was fitted to a combinationof two magnetic sextets. The sub-spectrum with higher hyperfine field (Hh.f.) value originates from theFe3+ in the A sites whereas the other originates from the Fe3+ in the B sites. The applied field (5T)
spectrum gave a combination of two magnetic quadruplets, due to the reduction of the 2−5 peaks. By
applying an external field, these two sub-spectra of the A and B sites are clearly separated, providing more
precisely fitted spectra and area ratios of Fe3+. The values of Hh.f. for the A and B sites with no applied field
are 47.9 and 50.7 T, respectively, whereas the literature values are 48.1 and 50.5 T, correspondingly. Our
spectra thus show considerably good agreement with the reported values within experimental errors [3].
The non-zero values of Q.S. indicate that the sample contains a non-cubic structure, i.e. a tetragonal
structure or local distortion, which agrees with the crystal structure confirmed from the XRD pattern. The
values of I.S. for the A and B sites’ sub-spectra are 0.18 mm/s and 0.29 mm/s respectively, indicating thatthey originate from Fe3+ ions, and not Fe2+. From the fit results of the 5 T spectrum, the area populationsof the two types of Fe3+ ions distributed in the A and B sites were 46.3 and 53.7%, respectively. The

41

relative area ratio shows that the concentration of Fe3+ ions is higher in the B sites than in the A sites. Thissuggests that the structure contains anti-site defects where some of the Cu2+ from the B sites are exchanged
with the Fe3+ in the A sites.
The magnetic properties are summarized in Table 2. The MS for the cubic and tetragonal CuFe2O4
samples are 25 and 26.9 emu/g, respectively. The values are in good agreement with the calculated values
MSCalc.. The slightly higher value of the experimental MS is possibly due to the presence of anti-site defects,
as observed in the Mössbauer study. The coercivities of the cubic and tetragonal CuFe2O4 is 130 and 870
Oe, respectively. The higher coercivity in the tetragonal sample may be due to the anisotropy induced
during the tetragonalization process.

cubic spineltetra. spinel
CuO

20

Exp.
Fit
Fe3+ (A)Fe3+ (B)heat-treatedtetragonal

30

Hext.=0 T

Absorption (arb.)

Intensity (a. u.)

as-fluxed
cubic

40

50

60

Hext.=5 T

2θ (deg.)-10Fig. 1. XRD patterns of as-fluxed (top) andheat-treated (bottom) CuFe2O4 particles.
Table 1. Mössbauer fitting parameters.

Hext
SubI.S.
(T) spectrum (mm/s)
Fe3+(A) 0.26
0Fe3+(B) 0.36
Fe3+(A) 0.19
5
Fe3+(B) 0.28

Hhf
(T)
47.9
50.7
52.5
45.4

Q.S.
L.W.
(mm/s) (mm/s)-0.02 0.473-0.28 0.412
0.01 0.479-0.02 0.635

Fe3+(A)
Fe3+(B)

-5

0

5

10

Velocity (mm/s)

Fig. 2. Room temperature 57Fe Mössbauer spectraof tetragonal CuFe2O4 particles without external
magnetic field (top) and with 5T external magnetic
field (bottom).

Area
(%)
38.1
61.9
46.3
53.7

Table 2. Magnetic properties of the cubic
and tetragonal CuFe2O4 particles.

*Isomer shift with respect to α-Fe

References[1] H. Yanagihara et al., J. Appl. Phys. 111 (2011) 07C122-1.
[2] T. Niizeki et al., Appl. Phys. Lett. 103 (2013) 162407-1.
[3] B. J. Evans and S. S. Hafner, J. Phys. Chem. Solids 29 (1968) 1573.

42

4.6

Low temperature Mössbauer study on spherical α”-Fe16N2 core–shell
nanoparticles with high magnetic anisotropy

E. Kita, K. Shibata, Y. Sasaki, M. Kishimoto, H. Yanagihara
Fe nitrides have a variety of crystalline structures depending on the concentration of nitrogen. There
are a few ferromagnetic nitrides, which have been studied from the practical viewpoint [1]. α”-Fe16N2 has
a tetragonally distorted structure from a BCC structure, in which one of the <100> axes is elongated andthe nitrogen atoms are ordered. This substance has been studied by many people for its high saturation
magnetization; the compound also exhibits a uniaxial magnetic anisotropy due to the distorted structure,
showing promise for use in applications such as high-performance magnetic data recording tapes [2] withcore–shell type spherical nanoparticles (NPs) [3]. Recently, new permanent magnet materials that do not
require rare elements have been highly sought and α”-Fe16N2 is a good candidate, as it has high saturation
moments and a large anisotropy constant (Ku).
The amplitude of Ku is an important parameter not only for bulk applications but also for therealization of perpendicular magnetic thin films. We have reported that Ku of the core–shell α”-Fe16N2 NP,
estimated from typical torque measurements and room temperature Mössbauer measurement, is 4.4 × 106
erg/cm3 [4]. In order to evaluate the precise amplitude of Ku, the portion of α”-Fe16N2 in NP should be
carefully analyzed. We performed detailed torque measurements and re-analyzed the low-temperature
Mössbauer spectrum [5].
The core–shell α”-Fe16N2 NPs were prepared using NH3 nitrification. First, Fe3O4 particles with adiameter of 18 nm underwent hydrogen reduction. Succeeding nitrification was carried out in an
atmosphere of H2 and NH3 [3]. Magnetically aligned samples were prepared by drying the organic solventof particles on the polymer films in a magnetic field parallel to the films.
Figure 1 shows the Mössbauer spectrum of α”-Fe16N2 NPs recorded at 4.2K. We have alreadyevaluated the portion of the α”-Fe16N2 by using room temperature Mössbauer data, however analysis ofdata recorded at low temperature is desirable because influence of recoil absorption is less at low
temperature. It is noted that the surface oxide was in paramagnetic state at room temperature and becamealmost ordered at low temperatures.
Data fitting was carried out using a commercially available program, MossWinn 4.0. Obtained
Mössbauer parameters are listed in Table1. It was found that a paramagnetic part seen at room temperature[4] changes into a magnetic sextet with large internal field of 486 kOe. From the amplitudes of thehyperfine field and the I.S., the part was concluded to be mainly the Fe oxide composed of Fe3+ ions.
Resulted portion of the α”-Fe16N2 phase was 54.4 %, slightly less than that at room temperature, 56.2% [4].
It can be elucidated by the fact that the lower Debye temperature for the oxide shell part resulted in thedecrease in the observed oxide volume at room temperatures. The magnetic anisotropy energy for core–shell α”-Fe16N2 NPs was evaluated by the rotational hysteresis loss obtained from torque measurements.
The saturation magnetization and anisotropy constant were deduced to be 234 emu/cm3 and 6.9×106
erg/cm3, respectively [5]. These values are more precise than the previous data [4] because the accurate

43

volume fraction was determined by using the low temperature Mössbauer data.

Fig. 1 Mössbauer spectrum for the α”-Fe16N2 aligned sample recorded at 4.2K. Solid lines show theresults of the fit, which are summarized in Table 1. Corresponding peak positions of sub-spectra are
indicated by three bars for magnetic sub-spectra of the α”-Fe16N2 core and two bars, magnetic
sextet (M), and paramagnetic doublet (D), for the outer shell of Fe oxides (Fe-O) [5].

Table 1. Mössbauer parameters: hyperfine field (Hhf), isomer shift (I.S.),
quadrupole split (Q.S.), and area ratio for α”-Fe16N2 aligned nanoparticles
at 4.2K [5] .
Phase

Site
4e

Hhf (kOe)
304

I.S.(mm/s)a
0.200

Fe16N2

8h

334

4d
D

Fe-O
a

M

Area (%)
13.8

0.28

Q.S. (mm/s)−0.313
0.166

423

0.315

−0.162

15.2

−
486

0.448

1.97

11.6

0.513

−0.05

34.0

Relative to room temperature α-Fe.

References[1] J. M. D. Coey and P. A. I. Smith, J. Magn. Magn. Mater. 200 (1999) 405.
[2] Y. Sasaki et al., IEEE Trans. Magn. 41 (2005) 3241.
[3] K. Shibata et al., J. Magn. Soc. Jpn. 30 (2006) 501.
[4] E. Kita et al., J. Magn. Magn. Mater. 310 (2007) 2411.
[5] E. Kita et al., AIP Advances 7 (2017) 056212.

44

25.4

4.7

Characterization of oxide thin films with RBS technique

R. Patel, Y. Ikeda, Y. Hisamatsu, S. Sharmin, H. Yanagihara
Barium hexaferrite (BaFe12O19; BaM) is a magnetic oxide with the magnetoplumbite structure which
has a hexagonal close packed (HCP) oxygen frame-work structure [1]. BaM has unique magnetic
properties such as high uniaxial magnetic anisotropy, moderate saturation magnetization, and high Curie
temperature [2-3]. Previous studies showed that the BaM films grown by various different methods suchas, pulsed laser deposition, liquid phase epitaxy, and radio frequency sputtering have lower saturation
magnetization and squareness ratio, compared with the bulk [4-8]. The reason for this is not wellunderstood until now. For applied purposes, the high quality thin film growth technique is required toachieve large magnetization comparable to the bulk. Nevertheless to say, fundamental physical propertiesof a film are strongly dependent on chemical composition if the film is alloy or compound. Thus, thepurpose of this research is to understand the effect of composition on the magnetic behavior of the barium
hexaferrite (0001) thin films.
The epitaxial growth of BaM (0001) thin films was performed on an α-Al2O3 (0001) substrate via
radio frequency (RF) magnetron sputtering. Stoichiometric (BaFe12O19) target with a diameter of 68 mm
was used. The flow rate of Ar was 10 sccm; total pressure inside the sputtering chamber was maintained at
0.57 Pa. Prior to the deposition, the substrates were annealed under vacuum at the growth temperature of
800°C for 1 hour. The RF power of the sputtering process was set at either 50 or 100 W. The BaM (0001)
thin films of 101 nm thickness were deposited. The BaM (0001) thin films were post-annealed in
atmosphere at 1000 °C for 10 minutes. Compositional characterization by Rutherford backscattering
spectroscopy (RBS) was carried out using 1MV Tandetron at UTTAC.
The RBS spectra of BaM (0001) thin films for RF power of 50 and 100 W are shown in Fig 1. The
experimentally obtained composition ratios of Ba to Fe in BaM (0001) thin films are shown in Table 1.
The evaluated off-stoichiometric ratio of Ba:Fe was 1:9 (for the growth at 100 W), suggesting that some
defects exist in the hexaferrite films obtained. The crystal structure of barium hexaferrite is close-packed
layers form with four fundamental blocks, S, S*, R and R*. The S* and R* blocks can be obtained simply
through the rotation of the S and R blocks, respectively, by 180° with respect to the c-axis. A pair of either
S and R or S* and R* conserves charge neutrality and Ba ions occupy the R (or R*) block. Therefore, anoff-stoichiometric M-type hexaferrite may involve the other oxide block such as T-block. The estimatedconcentration of T-block is about 23%, which affects neither magnetization nor magnetic anisotropy
because the T-block is composed of Ba2+, Fe3+ and O2- ions and is magnetically compensated. The rest of S
R S* R* block influences Ms and Ku(eff.), which are 292 emu/cm3 and 2.46 Merg/cm3, respectively, andthey are close to the experimental values. Therefore, such reduction of Ms and Ku(eff.) in BaM (0001) thinfilms could be explained by the existence of the T-block.
In summary, the BaM (0001) thin films were deposited on α-Al2O3 (0001) substrates by RFmagnetron sputtering. The composition study revealed that the barium to iron ratio in the deposited thinfilm is variable. The effect of RF power on the composition helps us to understand the reason for the lower

45

saturation magnetization.

Fig. 1. The RBS spectra of BaM (0001) thin film with RF power of 50 W and 100 W.

Table 1. The composition ratios of Ba to Fe determined from RBS spectra.
TargetRF Power (W)Bax

Fe13-xBaFe12O19

50

0.84

12.16

BaFe12O19

100

1.31

11.69

References
1. R. O. Handley, Modern Magnetic Materials (Wiley, New York, 2000).
2. B. T. Shirk et al., J. Appl. Phys. 40 (1969) 3.
3. B. D. Cullity and C. D. Graham, Introduction to Magnetic Materials (Wiley, New York, 2009).
4. H. J. Masterson et al., J. Appl. Phys. 73 (1993) 8.
5. S. A. Oliver et al., J. Magn. Magn. Mater. 213 (2000) 326.
6. A. Lisfi et al., Appl. Phys. Lett. 83 (2003) 4.
7. S. D. Yoon et al., J. Appl. Phys. 4 (2004) 96.
8. H. Xu et al., Appl. Surf. Sci. 257 (2011) 2689.

46

4.8

Low temperature synthesis of highly oriented Si1-xGex (x: 0–1) on an
insulator by Al-induced layer exchange

K. Toko, T. Suemasu
A composition tunable Si1-xGex alloy has a wide range of applications, especially to electronic andphotonic devices. We investigate the Al-induced layer exchange (ALILE) growth of amorphous Si1-xGex
on an insulator (SGOI). Figure 1 presents a schematic of the sample preparation process. Preparation of
the Al and amorphous (a-) Si1-xGex layers (each 50 nm thick) on a SiO2 glass substrate was performed atroom temperature using radio frequency (RF) magnetron sputtering (base pressure: 3.0 × 10-4 Pa) with Ar
plasma. The RF power was set to 50 W for all of the Si1-xGex targets. The Ge composition x in the prepareda-Si1-xGex layers was determined to be 0, 0.15, 0.3, 0.6, and 1 by Rutherford backscattering spectrometry(RBS) employing 2.0MeV 4He ions from 1MV Tandetron at UTTAC. Between the two deposition cycles,
the Al film was exposed to air for 30 min to form a native Al oxide layer as a diffusion-limiting layer [1].
The samples were then annealed at 340–450°C in a N2 ambient chamber with an in-situ optical
microscope observation system until theWet etchinglayer exchange was finished. The Al andAlOx

AlOx layers were then etched away withLayer exchange

HF solution (HF: 1.5%) for 1 min.
The nucleation rate n and lateralFig. 1. Schematic image of the sample preparation procedure.

1011

Figure 2(a) shows that there is no clear

1010

diffusion-limiting
thicknessstrongly

AlOx

layer

depends

whose
on

the

humidity during Al air exposure. Figure
2(b)

shows

that

vg

increaseswithincreasing Ge fraction, which is the same
behavior as the crystallization of thea-Si1-xGex layers. We note that the ALILE
provides a vg two orders of magnitude
higher than that of the solid phasecrystallization (SPC) of a-Si1-xGex [2]which leads to large domain growth.
From the Arrhenius equation and theresults from Figs. 2(a) and 2(b), we

109
108
107

(b)

102

n0 [cm-3 h-1]

result suggests that n is determined by the(a)vg [μm h-1]

dependence of the Ge fraction on n. Thisn [cm-3 h-1]

dependent nuclei density and domain size.

Activation energy [eV]calculated from the slopes of the time

101
100

5.0
4.0

En

3.0
Eg

2.0
1040

(d) 1020

1038

1018

1036

1016

1034

1014

1032

ALILE
SPC

1030
1.4

1.5
1.6
1000/T [K-1]

(c)
ALILE
SPC

1028

0

1
0.5
Ge fraction in SiGe x

1012

v0 [μm h-1]

growth velocity vg of the samples were

1010
108

Fig. 2. Growth properties of the Si1-xGex (x: 0, 0.15, 0.3, 0.6, and1) samples. Arrhenius plots of the (a) nucleation rate n and (b)lateral growth velocity vg. (c) Ge fraction dependence of theactivation energies of nucleation En and lateral growth Eg. (d) Ge
fraction dependence of the frequency factors of nucleation n0 andlateral growth v0. For comparison, the data of SPC regarding thenucleation of Si3 and Ge4 and the lateral growth of SiGe2 areshown in (c) and (d).

47

determined the activation energies of nucleation En and lateral growth Eg and the frequency factors of
nucleation n0 and lateral growth v0. Figures 2(c) and 2(d) show that both the activation energies andfrequency factors decrease with increasing Ge fraction x. These facts indicate that the lowering of thegrowth temperature with increasing x arises from the reduction of the activation energies. Therefore, we
compared the growth characteristics between ALILE and SPC as follows. Figure 2(c) shows that ALILE
exhibits a lower En than SPC [3, 4]. This is because, with ALILE, SiGe nucleates in the Al grainboundaries at a lower interfacial energy compared with SPC, where SiGe nucleates in the amorphous SiGe
layer. Figure 2(c) also shows that Eg is almost the same for ALILE and SPC [2]. This is reasonableconsidering that Eg corresponds to the energy required for SiGe atoms to adhere to crystalline SiGe. Figure2(d) shows that ALILE exhibits a lower n0 than SPC [3,4]. This can be explained by the lower density of
SiGe atoms in Al for ALILE than that of amorphous SiGe for SPC. Figure 2(d) also shows that ALILE
exhibits a higher v0 than SPC [2]. This is because the SiGe atoms migrate faster in Al for ALILE than inamorphous SiGe for SPC. The above discussion accounts for why ALILE can provide larger SiGe grains
at lower temperature compared with SPC.
The crystal orientation and actual grain size of the Si1-xGex layers formed at low temperatures (≤400°C) were evaluated using electron backscatter diffraction (EBSD). The Si1-xGex layers were highly(111)-oriented in the entire SiGe composition range. The (111) orientation can be explained from theperspective of the appearance of the energetically stable plane [1]. The Si1-xGex layers had grains withdiameters of several tens of µm. These actual grain sizes are smaller than the domain size observed fromoptical microscopy because the domains are divided into several grains. The (111) fraction and grain size
did not depend on the SiGe composition, but correlate roughly with the growth rate. These results showthat slow annealing is a key to fabricate a highly oriented, large-grained SiGe layer regardless of thecomposition. Thus, we have demonstrated SiGe layers on an insulator with a (111) orientation fraction ofover 95% and a grain size over 50 µm over the entire SiGe composition range. These values are thehighest among the low temperature synthesized SGOIs.
In conclusion, we have achieved ALILE growth of a-Si1-xGex on insulators at low temperatures (≤400°C) over the entire composition range. The ALILE provided a low nucleation frequency and highlateral growth velocity, resulting in large Si1-xGex grains with diameters of no less than 50 µm. The area
fractions of the (111) orientation were more than 95%. The SGOI fabricated in this study is useful as
virtual substrates allowing advanced materials to be integrated on three-dimensional LSIs, glass, and evena plastic substrate.
The authors are grateful to Dr. D. Sekiba of UTTAC for RBS analyses.
References[1] K. Toko et al., Appl. Phys. Lett. 104 (2014) 022106.
[2] K. Toko et al., Appl. Phys. Lett. 94 (2009) 192106.
[3] K. Zellama et al., J. Appl. Phys. 50 (1979) 6995.
[4] P. Germain et al., J. Appl. Phys. 50 (1979) 6986.

48

4.9

Quantitative analysis of light elements in mixed-anion compound thinfilms

D. Kutsuzawa 1, Y. Hirose 1, D. Sekiba
Recently, oxyhydrides have been intensively studied because of their unique physical and/or
chemical properties. For example, hydride (H−) ions in perovskite-type ATiOxHy (A = Ca, Sr, Ba) arehighly labile, which enables low-temperature anion exchange reaction, such as H−/D−, H−/O2−, H−/N3−, etc.
These oxyhydrides are also expected as catalysts for synthesis of NH3 [1]. A significant issue in studies on
oxyhydrides is a quantitative analysis of hydrogen amount. However, conventional techniques such as
secondary ion mass spectrometry [2], thermal desorption spectrometry [2] and Rietveld refinement of
neutron diffraction [3] have relatively low accuracy due to matrix effect, interference from coexisting
impurities, and so on. In order to resolve this problem, we focused on elastic recoil detection analysis(ERDA), by which absolute amount of hydrogen in a film can be determined without a standard sample.
In this study, we investigated chemical composition of SrTiOxHy thin films by combination of ERDA andRutherford backscattering spectrometry (RBS) analysis [3].
SrTiOxHy thin films were prepared by a topotactic reaction reported previously [2]: First, precursor
SrTiO3 epitaxial thin films were grown on (LaAlO3)0.3(SrAl0.5Ta0.5O3)0.3 (100) substrate (LSAT) by pulsed
laser deposition method. Then, the obtained SrTiO3 films were sealed in an evacuated silica tube with
CaH2 powder, and reacted at 500°C for 24 hours in an electric furnace. The composition of the films
before and after the reaction was evaluated by ERDA and RBS with a 2.5 MeV 4He beam. The incident
angle of 4He was 15° from the sample surface and the detection angle for ERDA and RBS measurements
were 30° and 150°, respectively. Intensity of the spectra were normalized by dose amount of 4He particles
calculated from output current of a beam chopper located upstream of the beam path.
Figure 1 shows out-of-plane 2θ/θ X-ray diffraction patterns of STO/LSAT(100) epitaxial films before
and after CaH2 treatment. 200 diffraction peak of STO
was shifted to higher angle after the reaction, whichmeans out-of-plane lattice constant was shrunk by thereaction. This result suggests successful substitution of H−
for O2− in the perovskite lattice [2].
Figure 2 shows RBS spectra of the STO film after
CaH2 treatment. It was difficult to determine the cation
ratio of the film (Sr/Ti) from the spectrum, because Sr
peak from the film located at around 820 channel was
unclear due to overlap of Sr, La and Ta peaks from thesubstrate. Another substrate is needed to evaluate thecation composition precisely.

1

Fig. 1. 2θ/θ XRD patterns of STO/LSAT(100)epitaxial film before and after CaH2 treatment

The University of Tokyo

49

Fig. 2. RBS spectra of CaH2 treated
STO/LSAT(100) epitaxial film. Black circle isexperimental data and black, blue, red, green andgray lines are fitting lines of total, Sr, Ti, La andTa, respectively.

Fig. 3. ERDA spectra of STO/LSAT(100)epitaxial film before (gray) and after (black)
CaH2 treatment.

Figure 3 shows ERDA spectra of the films before and after CaH2 treatment. A clear peak of recoiledhydrogen was observed for the CaH2-treated film, while there is no such peak for the precursor film. Then,hydrogen to titanium ratio, NH/NTi, of the film were determined from the peak area considering recoil crosssection of each element and solid angles of the detectors for ERDA and RBS systems. The determined
NH/NTi value is 0.22, which agrees reasonably with the value reported previously (SrTiO2.75H0.25, CaH2
treatment at 530°C for 24 hours) [2].
In conclusion, we succeeded in evaluating hydrogen amount in a SrTiOxHy/LSAT(100) epitaxial
film by ERDA/RBS analysis. Our results demonstrated that these techniques are useful for composition
analysis of oxyhydrides.
References[1] 内田他、日本セラミックス協会秋季シンポジウム 2F02 (2015).
[2] G. Bouilly et al., Chem. Mater. 27 (2015) 6354.
[3] Y. Kobayashi et al., Nat. Mater. 11 (2012) 507.

50

4.10

Oxygen reduction reaction catalytic site analysis by Mössbauer
spectroscopy

S. Yasuda 1, R. Osaka1 , Y. Uchibori1
Iron-nitrogen-carbon (Fe-N-C) catalyst has been drawing attention as one of alternatives to costly andlimited resources such as Pt-based catalysts for oxygen reduction reaction (ORR) on cathodes of polymer
electrolyte membrane fuel cells. Fe-N-C catalyst possesses ORR catalytic structures where a metal ironatom is coordinated to nitrogen functionalized graphitic carbon, and the catalytic sites are supported on
conductive carbon materials. Recently, Fe-N-C coated on carbon nanotube (Fe-N-C/VA-CNT) catalyst
was produced by employing vertically aligned carbon nanotubes (VA-CNT) with a high specific surface
area (~1100 m2/g). Pyrolyzing iron(II) phthalocyanine (FePc) molecules and VA-CNT mixed composite
easily transformed the adsorbed FePc molecules into a large number of Fe-N-C structures on theindividual VA-CNT surfaces [1]. Although the Fe-N-C/VA-CNT catalyst exhibited a high ORR activity,
there are few studies on the Fe-N-C catalytic structure on CNT. In this study, Mössbauer spectroscopy was
employed to assess the Fe-N-C catalytic structure, and investigated the pyrolysis dependence of the
Fe-N-C catalytic structures.
Figures 1(a) and (b) show deconvoluted Mössbauer spectra of the Fe-N-C/VA-CNT catalysts preparedby 5 and 60 min pyrolysis time, respectively. Here, we remember previous Mössbauer studies assigned tothree Fe-N-C catalytic structures which consist of a Fe-ion coordinated by four nitrogen groups connected
to graphene structure (FeN4). They are a ferrous
low-spin FeN4 site (Doublet 1), a ferrous
intermediate spin FeN4 site (Doublet 2) and ferrous
high spin FeN4 site (Doublet 3), Fig. 1(c) showsbar graphs of the five components of Fe species
obtained from the peak deconvolution results. We
see that the fraction of iron carbide increases withincreasing the pyrolysis time, while the fraction of
the doublets decreases. The results indicate thatlong pyrolysis promote decomposition of the
Fe-N-C catalytic structure, resulting in productionof the iron carbide nanoparticles.
Fig. 1. Deconvoluted Mössbauer spectra of the
Fe-N-C/VA-CNT catalysts prepared by (a) 5minand (b) 60 min pyrolysis time, respectively, and (c)Bar graphs of Fe species.

References[1] S. Yasuda et al., Advanced Functional Materials
26 (2016) 738.

1

Hokkaido University, Sapporo, 060-0810, Japan

51

4.11

Sputtering loss of Zn nanoparticles in SiO2 induced by MeV C60+ ion
irradiation

H. Amekura1
Intending shape and/or size control of nanoparticles (NPs) embedded in dielectrics, Zn NPs embedded
in silica glass (SiO2) were irradiated with C60+ ions of 2, 4, and 6 MeV in Takasaki Advanced Radiation
Research Institute, National Institute for Quantum and Radiological Science and Technology (QST).
However, we have observed highly serious sputtering loss of the NPs. The energy losses of Cn cluster ionsare often estimated under the approximation of independent n monomers with the same velocity with theincident cluster ion; i.e.,Si(E, C60) = 60 Si(E/60, C1)(1)

where i represents e (electronic) or n (nuclear) [1]. This formula indicates that the energy loss of C60 ion
with the energy E is equivalent to 60 times the energy loss of C monomer with the energy of E/60. While
we used C60 ions of 2–6 MeV, the corresponding monomer with the same velocity has the energy E/60 =33–100 keV. At the beginning of this study, we expected the collisional mechanism for sputtering under10

unirrad2

atoms/cm )

Se

10

16

15

C60 => SiO2

Zn Content (x10Energy Loss S (keV/nm)

33-100 keV C monomer ion irradiation, because of the low energies. Consequently, the same were

Sn

5

0

0.5

1
Energy (MeV/C60)

8
6
4
2
0

5

6 MeV
4 MeV
2 MeV

MeV C 60+ => Zn NPs in SiO 2

1011

1012
1013
Fluence (C60+/cm2)

1014

Fig. 1(Left). Energy dependences of electronic and nuclear energy losses (Se, Sn) of C60 ion in
crystalline SiO2 were estimated from those of C monomer ion under the approximation of
independent C monomers with the same velocity. The energy losses of the C monomer were derived
from SRIM 2013 code. The irradiation experiments were carried out at the energies indicated byarrows.
Fig. 1(Right). Fluence dependences of Zn content in the amorphous SiO2 samples including Znnanoparticles. The samples were irradiated with C60+ ions of 2, 4, and 6 MeV. The Zn contents were
determined by RBS.
1 National Institute for Materials Science (NIMS)

52

expected for 2-6 MeV C60 irradiation, because of the same velocities. Figure 1 shows the energy
dependences of the electronic and nuclear energy losses, which were calculated under the approximationof the independent monomers with the same velocity as the incident cluster ion. Although the electronic
loss Se is predominant over the nuclear loss Sn at the energies where the experiments were carried out as
indicated by arrows, the contributions of Sn cannot be neglected.
While Se increases with increasing the energy, Sn decreases. If the sputtering efficiency increases(decreases) with increasing the energy, the predominant mechanism of the sputtering by C60 ions in theenergy range of 2–6 MeV is determined as the electronic (nuclear) origin. To experimentally determine theenergy dependence of the sputtering induced by C60 ions, the fluence dependence of the Zn content of thesamples was determined by Rutherford backscattering spectrometry (RBS). Since the Zn NPs were formedby 60 keV Zn+ ion implantation, they were formed only near the surface shallower than 70 nm. They can
act as sputtering markers.
A He+ ion beam of 1.6 MeV from the 1 MV Tandetron at UTTAC was used. The beam size was 1 mm
× 1 mm. The scattering angle and the solid angle of the surface barrier detector were 150° and 0.00785 sr,
respectively. The surface normal of the sample was tilted 5° off from the beam axis towards thebackscattering direction, following the IBM geometry [2]. Each sample was irradiated to the He+ dose of
420 nC. The data were analyzed using RUMP code [3] and the Zn content was determined.
The fluence dependence of the Zn content for the irradiation of 2, 4, and 6 MeV C60+ ions is shown in
Fig. 1(Reft). Although the nominal Zn content is 1.0 × 1017 atoms/cm2, an unirradiated value estimated is
9.44 × 1016 atoms/cm2. Clear losses were observed at the fluence of 1 × 1013 C60+/cm2 or higher. The loss
was higher for higher ion energy, indicating that the electronic energy loss is the predominant process ofthe sputtering induced by C60 ions of 2–6 MeV in Zn NPs embedded in SiO2.
References[1] S. Bouneau, et al., Phys. Rev. B 65 (2002) 144106.
[2] M. Mayer, Rutherford Backscattering Spectrometry (RBS), Lecture note (2003).
http://users.ictp.it/~pub_off/lectures/lns022/Mayer_1/Mayer_1.pdf.
[3] L.R. Doolittle, Nucl. Instrum. Methods Phys. Res. B 15 (1986) 227.

53

4.12

HR-RBS study of the rutile TiO2(110) surface

N. Nagatsuka 1, K. Fukutani １, E. Noguchi, I. Harayama, D. Sekiba
Titanium dioxide (TiO2) is a model system of transition metal oxides, and its surface has received muchattention in application to a photocatalyst and a transparent conductive film. However, the surface
electronic states of TiO2 are yet to be elucidated due to strong electron correlation and electron-phonon
interaction. It has been reported that structural defects dope excess electrons in TiO2 exerting strong
effects on the conductivity and catalytic activity of the surface. It is also reported that the excess
electrons doped by the defects form polaronic states at the rutile (110) surface with substantial
deformation of the lattice [1]. There are three types of defects: an oxygen vacancy at the topmost surface,an oxygen vacancy in the subsurface region and a titanium interstitial. Theoretical calculations haveindicated that these defects cause different electronic states and lattice structures [2,3]. Although a lot ofefforts have been made to clarify the electronic states associated with these defects, few experimental
studies on the lattice structure have been reported. Since the lattice structure is closely related to theelectronic state, information of the lattice deformation induced by defects is of crucial importance.
In the present study, we investigated the lattice structure of the rutile TiO2(110) surface withhigh-resolution Rutherford backscattering spectroscopy (HR-RBS). The TiO2(110) surface was preparedby repeated cycles of Ar ion sputtering and annealing in an ultra-high vacuum, and oxygen vacancies werecreated by irradiation of electrons at 500 eV. HR-RBS measurements were performed with He+ ions at 400
keV and the scattered ions were analyzed by a high-resolution magnetic spectrometer.
Figure 1 shows two-dimensional channel
maps for clean and electron-irradiated (ESD)
surfaces of TiO2 (110) around the [100] axison the (010) plane. Channeling dips areclearly observed along with the surface
peaks for both surfaces. The channelingprofile looks asymmetric, which is causedby the structural asymmetry. Furthermore,
the channeling dip of the ESD surface at thesurface peak of Ti is slightly narrower thanAngle from [100] (deg.)

Angle from [100] (deg.)that of the clean surface suggesting a slight Fig. 1 2D-channel maps for clean and electron-irradiateddisplacement of Ti.
surfaces of rutile TiO2(110) around [100].
References[1] M Setvin et al, Phys. Rev. Lett. 113 (2014) 086402.
[2] E Finazzi et al, J. Phys. Chem. C 113 (2009 ) 3382.
[3] B. J. Morgan et al, J. Phys. Chem. C 113 (2009) 7322.
１

Institute of Industrial Science, University of Tokyo

54

4.13

Profiling of hydrogen in thick films employing transmission ERDA
technique

H. Naramoto, M. Sataka, H. Kudo, K. Yamazaki, K. Sasa, H. Oshima
In metallic materials, diffusional behaviors of hydrogen as mobile interstitials are sensitively
influenced by atomic disorders, which results in the serious deterioration of structural and/or transport
properties. In order to understand the relevant mechanisms, it is indispensable to know the spatial
distribution and the microstructure of hydrogen-disorder aggregates. There have been developed various
kinds of hydrogen detection methods employing nuclear collision processes [1]. They are mostly suitable
for the detailed depth-profiling but some additional improvements are required to obtain thehydrogen-profile deep inside the samples.
As the first step of this study, the recoil cross sections of 4He ions with 1H were surveyed in the wide
energy range. Figure 1 shows the evaluated differential cross sections of the hydrogen recoil process as afunction of incident

4

He2+ energy E for 8

different recoil angles ϕ [2]. One can see thebroad resonance nature of recoil cross sections at
the 4He ion energy E~9 MeV, which is due to the
nuclear elastic scattering of the non-Rutherford
type. Also, the cross sections become higher forsmaller ϕ. These are of remarkable difference
from the dependences on E and ϕ in the
Rutherford case. At E≅10 MeV, for example, therecoil cross sections are as large as 350 times
those in the Rutherford case, so that the detection
sensitivity of hydrogen is extremely enhanced.
Such advantage probably allows 2-demensionalhydrogen mapping by the transmission elastic
recoil detection analysis (transmission ERDA[3]) combined with the micro-beam scanningsystem on the beam line of the 6MV tandem

Fig. 1. Evaluated energy dependence of H(α, p)4He recoilcross sections for 8 different recoil angles ϕ.

accelerator at UTTAC [4].
In the experiments, 10 MeV 4He2+ was employed to perform transmission ERDA for an Al film of
thickness t=170 µm, which satisfies the condition for the incident 4He2+ beam to be stopped within the film.
The surface barrier detector (SBD) was placed at ϕ=0°, which covers a fixed solid angle of 1.28 msr. The
estimated hydrogen-probing depth is around 40 µm from the Al surface.

Figure 2 shows the transmission

ERDA spectrum of recoiled hydrogen from the hydrogen-containing standard sample of Kapton (t=7.5µm)/H-charged Al (t=170 µm), which was measured at ϕ=0° under the normal incidence of 10 MeV 4He2+.
The observed peak is reasonably in the estimated range between 3.239 and 3.688 MeV, corresponding to55

Fig. 2. Transmission ERDA spectrum under thenormal incidence of 10 MeV 4He2+ to Kapton(t=7.5µm) /H-charged Al (t=170µm).

Fig. 3. Transmission ERDA spectrum under thenormal incidence of 10 MeV 4He2+ to H-charged Al(t=170 µm).

the back- and front-side of the Kapton film on H-charged Al, respectively. The step around 5.6 MeV is dueto the detectable limit of SBD with the depletion layer of 300 µm thickness. The signal/noise ratio at thehydrogen peak amounts to ∼160 and, accordingly, sensitive detection of hydrogen can be expected in thepresent measurement system. The asymmetric hydrogen peak is attributed to the energy struggling ofrecoiled hydrogens in the outgoing paths and also to the energy dependence of the recoil cross section.
There still remains some background, probably resulting from the nuclear reactions of 4He2+ with 27Al. For
low-noise 2D-profiling, the hydrogen signals should be collected over a larger solid angle.
Figure 3 shows the spectrum from H-charged Al (t=170 µm) film measured under the same
conditions as those shown in Fig. 2. The step at 5.6 MeV is already noted earlier, while a sharp humparound 3.8 MeV is attributed to the charged hydrogens which possibly exist as blisters near the surface ofthe sample [5]. Reproducibility of the results was confirmed from the spectra measured for 7, 8 and 9
MeV 4He2+. For more detailed analysis, influence of possible nuclear reactions should be investigated.
The authors are indebted to Prof. G. Itoh (Ibaraki University) for providing us hydrogen-charged
pure Al films.
References[1] For example, K. Umezawa et al., Nucl. Instr. Meth. B33 (1988) 634.
[2] IBANDL (Ion Beam Analysis Nuclear Data Library); https://www-nds.iaea.org/exfor/ibandl.htm[3] J. Tiria et al., Nucl. Instr. Meth. B45 (1990) 147.
[4] A. Yamazaki et al., Nucl. Instr. Meth. B (2017) in press.
[5] T. Manaka et al., Materials Science Forum 879 (2017) 1220.

56

4.14

Heterogeneous carboxy group distribution across a polyamide active
layer of a ESPA2 thin-film composite reverse osmosis membrane

R. Tanaka1, T. Suzuki1, M. Niinae1
State-of-the-art thin-film composite reverse osmosis (RO) membranes have a composite structure
consisting of a nonwoven polyester layer (~50-150 μm) that backs an intermediate layer of polysulfone(~20-50 μm), which in turn supports an active layer of polyamide (< 100 nm) [1]. Among these threelayers, the performance of the membrane was mainly determined by a polyamide active layer [2].
However, due to its thin thickness and high surface roughness, it is not easy to obtain information on thephysicochemical properties of a polyamide active layer and accordingly, limited information has beenreported in the literature about the depth

1500

heterogeneity [3]. Therefore, the objective of
this study is to measure the concentration ofpolyamide active layer of ESPA2 RO
membrane (Nitto Denko Corp.) by probing
R-COO- with Ag+. This can actually be
performed by quantifying Ag in the sample
using

X-ray

photoelectron

1200
Yield (counts)

deprotonated carboxy group (R-COO-) of a

900

backscatteringS

spectrometry

1500

were

prepared+

distilled deionized water with resistivity
greater than 18 MΩ·cm (WA200, Yamato
Scientific Co., Ltd., Tokyo, Japan). All
reagents were purchased at guaranteed
reagent grade quality from Nacalai Tesque,Ag -treated ESPA2 (pH6.5)
SIMNRA fitting+
Ag -treated ESPA2 (pH10.1)
SIMNRA fitting

1200

using

Yield (counts)

solutionsCl0(RBS) for average across the polyamide.
All

O

(a)

(XPS) for very surface of the polyamide andRutherford

N

600
300

spectroscopy

Polysulfone support layer
SIMNRA fitting
Virgin ESPA2SIMNRA fitting

C

900
600
300

Inc. (Kyoto, Japan) or Wako Pure Chemical0

Industries, Ltd. (Osaka, Japan) and used

(b)
0.4

without further purification. Saturation ofAg
0.6 0.8 1.0 1.2 1.4 1.6
Backscattered He energy [MeV]

1.8

R-COO- with Ag+ was performed according

Fig. 1. RBS spectra obtained for (a) polysulfone support and virgin

to the procedures reported in the literature

ESPA2 membranes, and (b) Ag+-treated ESPA2 membranes at pH6.5[3]. The elemental composition of theand pH10.1. The average and standard deviation in Gamma

polyamide back surface was measured using

distribution of active layer thickness were determined from the+a K-Alpha™ XPS system (Thermo Fisher

nitrogen peak, oxygen peak, and the energy shift of the frontal peak forsulfur.

1 Yamaguchi University

57

Scientific Inc., Waltham, MA), whereas

Experimental data (XPS)

those for the polyamide entire layer wereModeling
Experimental data (RBS)

measured by RBS using 2MeV 4He2+ from
RBS spectra obtained for (a) polysulfone
support and virgin ESPA2 membranes, and(c) Ag+-treated ESPA2 membranes at pH6.5
and pH10.1 are shown in Fig. 1. As shownin Fig. 1, the peak intensity of Ag is higher
at pH10.1 than that at pH6.5, which means
morefractionof

R-COOHwasdeprotonated at higher pH. The RBS spectra

R-COO- concentration [mol/L]

1MV Tandetron at University of Tsukuba.

Modeling

0.8
0.6
0.4
0.2
0.0
3

were analyzed using the software SIMNRA

4

5

to obtain elemental compositions and other6
7
8
Aqueous pH

9

10

11

physicochemical properties of active layers.

Fig. 2. Concentrations of deprotonated carboxy group (R-COO-) in

The concentrations of deprotonated carboxy

the polyamide active layers of ESPA2 membrane as a function ofgroup (R-COO-) in the polyamide active

aqueous pH. Orange circles represent R-COO- concentrations near thelayers of ESPA2 membrane as a function ofactive layer surface measured by XPS, and blue circles represent

aqueous pH was summarized in Fig. 2. The

average R-COO- concentrations in the active layer measured by RBS.

comparison of Ag profiles measured byError bars indicate standard deviation of triplicate. Continuous lines

these two analytical methods revealed that

represent the modeling results. The RBS spectra for samples indicated-the concentration of R-COO at the surface

by arrows are shown in Fig. 1.

is higher than the average value acrosspolyamide. This result can be interpreted that the concentration of R-COO- in polyamide active layer ishighest at the surface, and gradually decreases with distance from the surface.

References[1] T. Suzuki et al., Water Res. 100 (2016) 326.
[2] R. J. Petersen, J. Membr. Sci. 83 (1993) 81.
[3] O. Coronell et al., Environ. Sci. Technol. 45 (2011) 4513.

58

4.15

Relationship between the abrasion of DLC coated layer and its
hydrogen content

Y. Yoshida 1, S. Kunitsugu2
In the automobile industry, improvement of fuel consumption has become an urgent matter from theviewpoint of the demand for reduction of global greenhouse gas emission. For improvement of fuelconsumption, it is necessary to improve such items as the heat efficiency of engine and drive wheels, orthe vehicle body weight. Above all, friction due to sliding between car parts occupies a large proportion ofenergy loss, and therefore, reducing friction loss is one of the important items for improving fuelconsumption.
There are two approaches to reduce the friction loss of the sliding parts. One is to lower the stirring
resistance with low-viscosity car oils, and another is to improve the wear resistance of car parts byapplying coatings that reduce their friction coefficients. Actually, automobile industries have attempted toreduce friction by the above two approaches, especially employing the diamond-like carbon (DLC)
coating. DLC is an amorphous carbon film with different fractions of sp3 and sp2 bonds, and is applied tomolds and mechanical parts because it has low friction and wear resistance.
DLC should wear when car parts slide with each other, however until now, there has been no detailed
report on the relationship between the wear and the hydrogen (H) concentration in DLC. Among the DLC
deposition methods, the cathodic arc (CA) deposition method can deposit DLC with the H concentrationof 5% or less. Furthermore, if a gas containing H is used as the plasma source, it is possible to control the
H concentration. In this work, we prepared DLC with different H-adding acetylene (C2H2) gases using
cathodic arc method and investigated their wear characteristics.
Hydrogen free DLC (ta-C; tetrahedral amorphous carbon) coatings were made on the steel disk bymeans of CA method using single gas of argon (Ar) as a plasma source, as illustrated in Fig. 1. Next, inorder to make a hydrogenated DLC (ta-C:H; Hydrogenated tetrahedral amorphous carbon), we also used a
mixture gas of Ar / C2H2 as a plasma source. The pressure in the chamber was fixed at 0.2 Pa and theC2H2 gas flow was varied as 0, 10, 60 sccm.
The hydrogen concentrations in the DLC coating films were
determined by Elastic Recoil Detection Analysis (ERDA) and
Rutherford Backscattering Spectrometry (RBS), using 2.5 MeV 4He2+
obtained from the Tandetron accelerator at UTTAC. For friction andwear tests, a SRV test system (SRV IV, Optimol instruments) was usedwith a reciprocating ball-on-disk configuration, shown in Fig. 2. We
dropped car oil on the steel disk coated with DLC. A reciprocating
frequency of 50.0 Hz and a sliding distance of 180 m were chosen for
the test condition.
1
2

TOYO advanced technologies Co., Ltd.
Industrial Technology Center of Okayama Prefecture59

Fig. 1. Schematic diagram ofcathodic arc deposition system.

Figures 3 and 4 show the ERDA spectrum of DLC and the correlation

Oscillationof H concentration with C2H2 flow rate, respectively. When single Ar gas wasused for arc discharge, the H concentration in DLC was 0.3 %. Even when
DLC was deposited using a mixed gas in which C2H2 was added to Ar at 10

Oil

sccm, the H concentration remained at 0.3%. When the flow rate of C2H2 wasincreased to 60 sccm, the yield of ERDA spectrum increased remarkably andin this case the H concentration was as high as 3.0%.

Ball
DLC
on DiskFig. 2. Schematic diagramof the SRV test system.

The friction and abrasion test was carried out for these DLC samples. Figure 5 shows optical
microscopic image of worn surface on DLC. Figure 6 shows the correlation between hydrogenconcentration and wear coefficient. The measured values of wear coefficient for the DLC samples are
6.6×10-12 and 2.8×10-11 mm3/(N×mm) for H concentration of 0.3%, while it is 5.7×10-11 mm3/(N×mm)
for H concentration of 3.0%.
In this study, the abrasion effect of H concentrations of only 3% or less was investigated. We willfurther investigate the abrasion process by increasing the H concentration in DLC.

Fig. 4. Correlation between hydrogencontent and C2H2 flow rate.

Fig. 3. ERDA spectrum of DLC.

Fig. 5. Optical microscopic imageof worn surface on DLC.

Fig. 6. correlation between hydrogencontent and wear coefficient.

60

4.16 Measurement of hydrogen content in DLC films
T. Imai1, T. Harigai1, H. Takikawa 1
Diamond-like carbon (DLC) films have amorphous structure composed of sp2 hybridized and sp3
hybridized bonds. DLC films have been used widely for applications in industry because DLC films haveexcellent properties such as high mechanical hardness and chemical inertness. DLC films can be classified
into four groups depending on the combinations between bonding nature and hydrogen contents: 1)
tetrahedral amorphous carbon (ta-C) films with dominant sp3 bonds and less hydrogen, 2) amorphous
carbon (a-C) films with dominant sp2 bonds and less hydrogen, 3) hydrogenated tetrahedral amorphous
carbon (ta-C:H) films, and 4) hydrogenated amorphous carbon (a-C:H) films.
Currently, the standardization on DLC films have been actively discussed, and "Carbon based films-Classification and designation" has been proposed to the TC107 secretariat [1]. In the project proposal,
DLC films are classified by using the sp3 bond fraction (sp3/[sp3+sp2]) and the hydrogen content obtained
from the NEXAFS and the RBS/ERDA measurements, respectively. However, it is difficult to introduce
these measurement methods as the DLC film analysis at the actual product due to high cost. Therefore, theclassification method based on optical constants measured by spectroscopic ellipsometry has been
proposed as a simpler and cheaper method [2]. In this experiment, the hydrogen content in DLC films
prepared using the T-shape filtered arc deposition (T-FAD) system is evaluated quantitatively forverification of the classification by optical constants and other classification methods.
DLC films were fabricated on Si substrates by the T-FAD. Graphite was used as a cathode. The
species and the flow rate of introduction gas (hydrogen, ethylene, and acetylene) to a chamber and theapplied bias voltage to the substrate were changed systematically. The contents of hydrogen and carbon
were analyzed using elastic recoil detection analysis（ERDA）at a recoil angle of 30° and Rutherford
backscattering spectrometry (RBS) at a scattering angle of 150°, respectively. 2.5 MeV 4He2+ obtained
from 1MV Tandetron at UTTAC was used for RBS/ERDA.
Figure 1 shows RBS and ERDA spectra for a DLC (ta-C) film prepared without gas introduction.
Those for a DLC (a-C:H) film prepared with ethylene gas introduced at 20 sccm are shown in Fig. 2. In
both cases, similar RBS spectra are observed. On the other hand, ERDA spectra are different. ERDA
spectrum in Fig. 1 shows negligible hydrogen signals at 430–460 channels which are attributed tohydrogen components of water molecules adsorbed on the surface. In contrast, hydrogen signals areobserved definitely in Fig. 2. The hydrogen content in the DLC film was determined using simulation
software SIMNRA. It was found that the hydrogen content increased with the flow rate increase of thehydrocarbon gas. This is because the number of hydrogen atoms contributing to the film growth increase
with increasing the flow rate of the introduced gases. However, when the substrate bias voltage wasapplied, the hydrogen content in the films decreased with the introduction of ethylene and acetylene gas,
and the hydrogen content increased with the introduction of hydrogen gas. The decrease of hydrogencontent with the introduction of ethylene and acetylene gas would be associated with the hydrogen-bond1

Toyohashi University of Technology

61

200
150

2000

Yield (counts)

Yield (counts)

3000

1000

0

0

100

200

300

400

100
50
0

500

0

100

Channel

200

300

400

500

ChannelFig. 1. RBS (left) and ERDA (right) spectra of hydrogen-free DLC film formed without gas introduction.
200

3000

Yield (counts)

Yield (counts)

150
2000

1000

0

0

100

200

300

400

500

100
50
0

0

100

Channel

200

300

400

500

ChannelFig. 2. RBS (left) and ERDA (right) spectra of hydrogenated DLC film formed by introducing 20 sccm of ethylene.

release by the bombardments of carbon ions and hydrocarbon ions in the near surface region under theapplied bias voltage. In the hydrogen gas introduction, it can be considered that hydrogen desorption by
ion bombardment effect was small because the average ion size was small in the chamber atmosphere.
On the proposed classification method, the films with the hydrogen content more than 5 at.% areclassified into hydrogenated DLC films (ta-C:H or a-C:H), and the films with the hydrogen content lessthan 5 at % are classified into hydrogen-free DLC films (ta-C or a-C). From this experiment, we havefound that ta-C or a-C films can be formed by the hydrogen-gas introduction at a flow rate of less than 30
sccm, and that ta-C or a-C films are obtained by acetylene- or ethylene-gas introduction at a flow rate ofmore than 30 sccm.
Finally, it is concluded that the hydrogen content of hydrogen-free DLC films and hydrogenated
DLC films prepared using a T-FAD method can be determined quantitatively by RBS/REDA measurement.
Based on these results, we will evaluate the classification method of DLC films by optical constants, andwill also propose other classification methods.
References[1] A. Tanaka, N. Ohtake, NEW DIAMOND, 32(4) (2016) 3, in Japanese.
[2] M. Hiratsuka et al., J. Sol. Mech. Mater. Eng. 7 (2013) 187.

62

5.
BEAM IRRADIATION EFFECT

5.1

Tolerance evaluation on single event of COTS-GNSS receivers

M. Komatsu1
For launch of space rocket in Japan, the Global Navigation Satellite System (GNSS) receivercurrently plays an important role [1, 2]. On the other hand, to respond to the market needs of reducing
costs of space launchers, it is urgent to develop compact, lightweight, and inexpensive space GNSS
receivers. Currently, R&D dept. of JAXA aims to construct low-cost and high-accuracy GNSS positioning
system for space launchers, utilizing COTS (Commercial off-the-shelf)-GNSS receivers.
In this research, the SEE (Single Event Effect) immunity was evaluated for three different
COTS-GNSS receivers (A, B, C). Figure 1 shows an example of plots of linear energy transfer (LET) vs.
cross section of SEFI (Single Event Function Interrupt). The experiment was performed for three different
LETs, and the cross sections were calculated from the total fluence and the endurance time, from test start
to SEE detection. During this evaluation, a GNSS signal player GSS6425 was used to generate and input
GNSS signal for these receivers (Fig. 2), and they were kept functioning – i.e., 3D positioning state.
The form of single event varied depending on the device of GNSS receivers. It was confirmed that
Receiver A was particularly vulnerable to SEFI. Since SEFI occurred at a high frequency, the single event
upset (SEU) cross section is unable to evaluate accurately, but it is considered that the probability of its
occurrence is lower than that of SEFI. For Receiver B, it was found that SEFI and SEU occurred with
about the same probability. For receiver C, SEU occurred frequently, while SEFI did not. The single event
latch up (SEL) did not occur for any receiver. In the actual receiver system designing, information on theform of SEE generated in each device determines the design policy in terms of what kind of backup /redundant system is to be constructed.

Fig. 2. Test configuration of GNSS Receiver A.

Fig. 1. LET vs. SEFI Cross Section of Receiver A.

References[1] Pratap Misra and Per Enge, “Global Positioning System”, 2nd Edition, 2006.
[2] S. Yamazaki et al., “New Effective Multipath Mitigation and Initial Assessment of the Radio andInertial Navigation Sensor ("RINA")”, Proceedings of the 29th ION GNSS, Sept. 12-16, 2016.

1 Japan Aerospace Exploration Agency

63

5.2

Preliminary evaluation of single event testing for regular use of the
6 MV tandem accelerator at University of Tsukuba

A.Maru1, H. Shindou1, K. Suzuki1, M. Sataka, K. Sasa
For electronic devices used in space, it is of technical importance to evaluate their radiation
tolerance. Influence of radiation on semiconductor devices is mainly categorized into either “single event
effect” or “total dose effect”. Tolerance of the electronic devices against these two effects must be
evaluated before using them in space. While the total dose test is generally performed by using gamma
rays from radioisotope sources, the single event test is performed by using energetic heavy ions which are
obtained from particle accelerators. In the latter case, several kinds of heavy ions having various energies
and enough projected ranges are needed because the electronic devices in space are exposed to many kindsof energetic heavy ions.
Soon after the 6 MV Pelletron tandem accelerator was installed at University of Tsukuba in 2014,
UTTAC built the beam line with the 1-m diameter vacuum chamber, as shown in Fig. 1, for dedicated use
for beam irradiation experiments not only by internal, but also by external users. With such improved
experimental environment, JAXA has started preliminary evaluation to use this beam line for single event
testing. Figure 2 shows the species and energies of ions available at the UTTAC 6 MV tandem accelerator[1], which allows selection of the heavy ions used for the single event testing. Before the testing, we
evaluated effective LET (Liner Energy Transfer) and projected ranges of heavy ions inside thesemiconductor devices by using SRIM (The Stopping and Range of Ions in Matter) code [2]. Under thecollaboration of JAXA and UTTAC, we introduced the beam scattering foil to form a uniformly
distributed ion beam and also installed the equipment characterizing the ion current distribution and ion
energy distribution for an accurate evaluation.

Fig. 2. Species and energies of ions available at
Fig. 1. The beam irradiation system at UTTAC.

UTTAC, reproduced from Ref. 1.

In the present work at UTTAC, the irradiation test for the device of simple 8k bit latch memory
circuits was performed using 42 MeV Si ions and 36 MeV O ions. The results can be compared directly1Japan Aerospace Exploration Agency (JAXA)

64

with those for the same device, obtained previously at Takasaki Ion Accelerators for Advanced Radiation
Application (TIARA) facility. Figure 3 shows comparison of the single event upset (SEU) cross sections
as a function of linear energy transfer (LET), together with the Weibull fitting curve. This demonstrates
that the data taken at the two facilities are consistent and, accordingly, assures that reliable radiation
tolerance tests for electronic devices used in space can be extended at UTTAC.

Fig. 3.

SEU cross sections as a function of LET, determined fromthe experiments at UTTAC and TIARA. Also shown is the Weibull
fitting curve.

References[1] 2016 version of the brochure of University of Tsukuba Tandem Accelerator Complex,
http://web2.tac.tsukuba.ac.jp/uttac/6MV-tandem[2] J. F. Ziegler, SRIM (The Stopping and Range of Ions in Matter) simulator, http://www.srim.org/

65

5.3

Effect of helium irradiation on tritium permeability of erbium oxide

W. Mao1, N.Breton1, H. Matsuzaki1, T. Terai 1
To limit tritium leakages in a breeding blanket of fusion reactor, a tritium permeation barrier can beused. Erbium oxide was selected as a promising candidate with a low tritium permeability. Thus, thepurpose of this study is to understand the irradiation effect of helium ions, originating from ﬁssion oflithium exposed to fusion-induced neutrons in the blanket, on the tritium permeability of erbium oxide [1].
To meet this objective, an erbium oxide of approximately 600 nm thickness was deposited on thesubstrate with the same quality as blanket materials. After division into subsamples, halves were irradiatedto 1−3 displacement per atom (dpa) with 0.4 MeV 4He+ from the 1MV Cockcroft-Walton accelerator at
UTTAC. The irradiation conditions are chosen so as to meet mathematical models of lithium blanket, inwhich the stopping and ranges of ions in matters (SRIM) was used for the irradiation damage calculation.
The samples were annealed at 773-973 K under hydrogen atmosphere (0.4 bar), as a safe substitute oftritium exposure. Through the nuclear reaction analysis of hydrogen, we will be able to obtain the depth
profile of diffused hydrogen during the annealing period, from which information on the permeability for
different samples is obtainable. Inﬂuence of irradiation on the hydrogen permeation reduction capacities of
erbium oxide could be quantiﬁed for non-irradiated and irradiated samples, as shown in Figure 1. Future
experiments and analysis are now under way.
In conclusion, the rise of permeability due to the irradiation seems serious in blanket operation. In thenext stage, the permeation study will be required using tritium itself to assert the promising nature of
erbium oxide, together with the structural analysis of irradiated erbium oxide.

Fig. 1. Irradiation dose dependence of normalized hydrogen concentration profile (C) for
samples annealed at 773 K for 12h. Co is the surface concentration of hydrogen.

Reference[1] A. Raffray et al., J. Nucl. Mater. 307 (2002) 21.

1

The University of Tokyo

66

6.
PUBLICATIONS

6.1

Journals

ACCELERATOR AND RELATED FACILITIES
1.

A. Yamazaki, K. Sasa, S. Ishii, M. Kurosawa, S. Tomita, Y. Shiina, S. Shiki, G. Fujii, M. Ukibe, M.
Ohkubo, A. Uedono, E. Kita, Development of a microbeam PIXE system for additive light elements
in structural materials, Nuclear Instruments and Methods in Physics Research B404 (2017) 92-95.

NUCLEAR AND ATOMIC PHYSICS
1.

R. Knobel, M. Diwisch, F. Bosch, D. Boutin, L. Chen, C. Dimopoulou, A. Dolinskii, B. Franczak, B.
Franzke, H. Geissel, M. Hausmann, C. Kozhuharov, J. Kurcewicz, S.A. Litvinov, G. Martinez-Pinedo,
M. Matos, M. Mazzocco, G. Munzenberg, S. Nakajima, C. Nociforo, F. Nolden, T. Ohtsubo, A. Ozawa,
Z. Patyk, W.R. Plaß, C. Scheidenberger, J. Stadlmann, M. Steck, B. Sun, T. Suzuki, P.M. Walker, H.
Weick, M.-R. Wu, M. Winkler, T. Yamaguchi, First direct mass measurements of stored neutron-rich
129,130,131

2.

Cd isotopes with FRS-ESR, Physics Letters B 754 (2016) 288–293.

A. Kusoglu, G. Georgiev, C. Sotty, D. L. Balabanski, A. Goasduff, Y. Ishii, Y. Abe, K. Asahi, M.
Bostan, R. Chevrier, M. Chikamori, J. M. Daugas, T. Furukawa, H. Nishibata, Y. Ichikawa, Y.
Ishibashi, R. Lozeva, H. Miyatake, D. Nagae, T. Nanao, M. Niikura, T. Niwa, S. Okada, A. Ozawa,
Y. Saito, H. Shirai, H. Ueno, D. T. Yordanov, and N. Yoshida, Magnetic moment of the 13/2+
isomeric state in 69Cu: Spin alignment in theone-nucleon removal reaction, Physical Review C 93,
054313 (2016).

3.

R. Knobel, M. Diwisch, H. Geissel, Yu.A. Litvinov, Z. Patyk, W.R. Plaß, C. Scheidenberger, B. Sun,
H. Weick, F. Bosch, D. Boutin, L. Chen, C. Dimopoulou, A. Dolinskii, B. Franczak, B. Franzke, M.
Hausmann, C. Kozhuharov, J. Kurcewicz, S.A. Litvinov, M. Matos, M. Mazzocco, G. Munzenberg,
S. Nakajima, C. Nociforo, F. Nolden, T. Ohtsubo, A. Ozawa, J. Stadlmann, M. Steck, T. Suzuki, P.M.
Walker, M. Winkler, and T. Yamaguchi, New results from isochronous mass measurements of neutronrich uranium fission fragments with the FRS-ESR-facility at GSI, Eur. Phys. J. A (2016) 52: 138 (11page).

4.

D. Q. Fang, Y. G. Ma, X. Y. Sun, P. Zhou, Y. Togano, N. Aoi, H. Baba, X. Z. Cai, X. G. Cao, J. G.
Chen, Y. Fu, W. Guo, Y. Hara, T. Honda, Z. G. Hu, K. Ieki, Y. Ishibashi, Y. Ito, N. Iwasa, S. Kanno,
T. Kawabata, H. Kimura, Y. Kondo, K. Kurita, M. Kurokawa, T. Moriguchi, H. Murakami, H. Ooishi,
K. Okada, S. Ota, A. Ozawa, H. Sakurai, S. Shimoura, R. Shioda, E. Takeshita, S. Takeuchi, W. D.
Tian, H. W. Wang, J. S. Wang, M. Wang, K. Yamada, Y. Yamada, Y. Yasuda, K. Yoneda, G. Q.
Zhang, and T. Motobayashi, Proton-proton correlations in distinguishing the two-proton emission
mechanism of 23Al and 22Mg, Physical Review C 94, 044621 (2016).

67

5.

X. Xu, P. Zhang, P. Shuai, R. J. Chen, X. L. Yan, Y. H. Zhang, M. Wang, Yu. A. Litvinov, H. S. Xu,
T. Bao, X. C. Chen, H. Chen, C. Y. Fu, S. Kubono, Y. H. Lam, D. W. Liu, R. S. Mao, X. W. Ma, M.
Z. Sun, X. L. Tu, Y. M. Xing, J. C. Yang, Y. J. Yuan, Q. Zeng, X. Zhou, X. H. Zhou, W. L. Zhan,
S. Litvinov, K. Blaum, G. Audi, T. Uesaka, Y. Yamaguchi, T. Yamaguchi, A. Ozawa, B. H. Sun, Y.
Sun, A. C. Dai, and F. R. Xu, Identification of the Lowest T = 2, Jπ = 0+ Isobaric Analog State in52

Co and Its Impact on the Understanding of β-Decay Properties of 52Ni, Physical Review Letters,

117, 182503 (2016).
6.

D. T. Tran, H. J. Ong, T. T. Nguyen, I. Tanihata, N. Aoi, Y. Ayyad, P. Y. Chan, M. Fukuda, T.
Hashimoto, T. H. Hoang, E. Ideguchi, A. Inoue, T. Kawabata, L. H. Khiem, W. P. Lin, K. Matsuta,
M. Mihara, S. Momota, D. Nagae, N. D. Nguyen, D. Nishimura, A. Ozawa, P. P. Ren, H. Sakaguchi,
J. Tanaka, M. Takechi, S. Terashima, R. Wada, and T. Yamamoto, Charge-changing cross-section
measurements of 12–16C at around 45A MeV and development of a Glauber model for incident energies
10 A–2100 A MeV, Physical Review C 94, 064604 (2016).

7.

S. Kimura, H. Ishiyama, H. Miyatake, Y. Hirayama, Y.X. Watanabe, H.S. Jung, M. Oyaizu, M. Mukai,
S.C. Jeong, A. Ozawa, Development of the detector system for β-decay spectroscopy at the KEK
Isotope Separation System, Nuclear Instruments and Methods in Physics Research B 376 (2016) 338–
340.

8.

P. Schury, M. Wada, Y. Ito, D. Kaji, F. Arai, M. MacCormick, I. Murray, H. Haba, S. Jeong, S. Kimura,
H. Koura, H. Miyatake, K. Morimoto, K. Morita, A. Ozawa, M. Rosenbusch, M. Reponen, P.-A.
Soderstrom, A. Takamine, T. Tanaka, and H. Wollnik, First online multireflection time-of-flight massmeasurements of isobar chains produced by fusion-evaporation reactions: Toward identification ofsuperheavy elements via mass spectroscopy, Physical Review C 95, 011305(R) (2017).

9.

K. Sawahata, A. Ozawa, Y. Saito, Y. Abe, Y. Ichikawa, N. Inaba, Y. Ishibashi, A. Kitagawa, S.
Matsunaga, T. Moriguchi, D. Nagae, S. Okada, S. Sato, S. Suzuki, T. Suzuki, Y. Takeuchi, T.
Yamaguchi, J. Zenihiro, Investigations of charge-changing processes for light proton-rich nuclei oncarbon and solid-hydrogen targets, Nuclear Physics A 961 (2017) 142–153.

10.

M. Mukai, Y. Hirayama, H. Ishiyama, H. S. Jung, H. Miyatake, M. Oyaizu, Y. X. Watanabe, S.
Kimura, A. Ozawa, S. C. Jeong, T. Sonoda, Search for efficient laser resonance ionization schemesof tantalum using a newly developed time-of-flight mass-spectrometer in KISS, Nuclear Instruments
and Methods in Physics Research B 376 (2016) 73-76.

68

ACCELERATOR MASS SPECTROMETRY
1.

Yukihiko Satou, Keisuke Sueki, Kimikazu Sasa, Kouji Adachi, Yasuhito Igarashi, First successful
isolation of radioactive particles from soil near the Fukushima Daiichi Nuclear Power Plant,
Anthropocene, 14 (2016) 71-76. DOI:10.1016/j.ancene.2016.05.01

2.

Kenji Kawamura, Ayako Abe-Ouchi, Hideaki Motoyama, Yutaka Ageta, Shuji Aoki, Nobuhiko Azuma,
Yoshiyuki Fujii, Koji Fujita, Shuji Fujita, Kotaro Fukui, Teruo Furukawa, Atsushi Furusaki, KumikoGoto-Azuma, Ralf Greve, Motohiro Hirabayashi, Takeo Hondoh, Akira Hori, Shinichiro Horikawa,
Kazuho Horiuchi, Makoto Igarashi, Yoshinori Iizuka, Takao Kameda, Kokichi Kamiyama, Hiroshi
Kanda, Mika Kohno, Takayuki Kuramoto, Yuki Matsushi, Morihiro Miyahara, Takayuki Miyake,
Atsushi Miyamoto, Yasuo Nagashima, Yoshiki Nakayama, Takakiyo Nakazawa, Fumio Nakazawa,
Fumihiko Nishio, Ichio Obinata, Rumi Ohgaito, Akira Oka, Jun’ichi Okuno, Junichi Okuyama, Ikumi
Oyabu, Frédéric Parrenin, Frank Pattyn, Fuyuki Saito, Takashi Saito, Takeshi Saito, Toshimitsu
Sakurai, Kimikazu Sasa, Hakime Seddik, Yasuyuki Shibata, Kunio Shinbori, Keisuke Suzuki,
Toshitaka Suzuki, Akiyoshi Takahashi, Kunio Takahashi, Shuhei Takahashi, Morimasa Takata, Yoichi
Tanaka, Ryu Uemura, Genta Watanabe, Okitsugu Watanabe, Tetsuhide Yamasaki, Kotaro Yokoyama,
Masakazu Yoshimori, Takayasu Yoshimoto, State dependence of climatic instability over the past
720,000 years from Antarctic ice cores and climate modelling, Science Advances, 08 Feb 2017, Vol.
3, no. 2, e1600446. DOI: 10.1126/sciadv.1600446

3.

Seiji Hosoya, Kimikazu Sasa, Tetsuya Matsunaka, Tsutomu Takahashi, Masumi Matsumura, Hiroshi
Matsumura, Mark Sundquist, Mark Stodola, Keisuke Sueki, Optimization of a ΔE − E detector for41

Ca AMS, Nuclear Instruments and Methods in Physics Research B, 406 (2017) 268-271.

BEAM AND ISOTOPE APPLICATIONS
1.

Masanori Kurosawa, Kimikazu Sasa, Ki-Choel Shin, Satoshi Ishii, Trace-element compositions
and Br/Cl ratios of fluid inclusions in the Tsushima granite, Japan: Significance for formation of
granite-derived

fluids,Geochimica

etCosmochimica

Acta,

182

(2016)

216–239.

doi:10.1016/j.gca.2016.03.015
2.

A. Uedono, M. Zhao, and E. Simoen, Probing the effect of point defects on the leakage blocking
capability of Al0.1Ga0.9N/Si structures using a monoenergetic positron beam, J. Appl. Phys. 120,
215702(1-7) (2016). [DOI: 10.1063/1.4970984]

3.

A. Uedono, M. Malinverni, D. Martin, H. Okumura, S. Ishibashi, and N. Grandjean, Vacancy-type
defects in Mg-doped GaN grown by ammonia-based molecular beam epitaxy probed using amonoenergetic positron beam, J. Appl. Phys. 119, 245702(1-6) (2016). [DOI: 10.1063/1.4954288]

69

4.

A. Uedono, Y. Tsukada, Y. Mikawa, T. Mochizuki, H. Fujisawa, H. Ikeda, K. Kurihara, K. Fujito,
S. Terada, S. Ishibashi, and S. F. Chichibu, Vacancies and electron trapping centers in acidic
ammonothermal GaN probed by a monoenergetic positron beam, J. Cryst. Growth 448, 117-121(2016). [DOI: 10.1016/j.jcrysgro.2016.05.015]

5.

W. Zhu, B. Mitchell, D. Timmerman, A. Uedono, A. Koizumi, and Y. Fujiwara, Enhanced
photo/electroluminescence properties of Eu-doped GaN through optimization of the growthtemperature and Eu related defect environment, APL Mater. 4, 056103(1-7) (2016). [doi:http://dx.doi.org/10.1063/1.4950826]

6.

S. Hooda, S. A. Khan, B. Satpati, A. Uedono, S. Sellaiyan, K. Asokan, D. Kanjilal, D. Kabiraj,
Nanopores formation and shape evolution in Ge during intense ionizing irradiation, Microporousand Mesoporous Mat. 225, 323-330 (2016). [doi:10.1016/j.micromeso.2016.01.006]

7.

A. Uedono, M. M. Islam, T. Sakurai, C. Hugenschmidt, W. Egger, R. Scheer, R. Krause-Rehberg,
K. Akimoto, Vacancy behavior in Cu(In1−xGax)Se2 layers grown by a three-stage coevaporation
process probed by monoenergetic positron beams, Thin Solid Films 603, 418-423 (2016). [DOI:
10.1016/j.tsf.2016.02.057]

8.

K. Kojima, Y. Tsukada, E. Furukawa, M. Saito, Y. Mikawa, S. Kubo, H. Ikeda, K. Fujito, A.
Uedono, and S. F. Chichibu, Electronic and optical characteristics of an m-plane GaN single
crystal grown by hydride vapor phase epitaxy on a GaN seed synthesized by the ammonothermal
method using an acidic mineralizer, Jpn. J. Appl. Phys. 55, 05FA03(1-4) (2016). [DOI:
10.7567/JJAP.55.05FA03]

9.

A. Uedono, S. Armini, Y. Zhang, T. Kakizaki, R. Krause-Rehberg, W. Anwand, A. Wagner,
Surface sealing using self-assembled monolayers and its effect on metal diffusion in porous lowk dielectrics studied using monoenergetic positron beams, Appl. Surf. Sci. 368, 272-276 (2016).
[DOI:10.1016/j.apsusc.2016.01.267]

10.

S. F. Chichibu, K. Kojima, Y. Yamazaki, K. Furusawa, and A. Uedono, “Controlling the carrier
lifetime of nearly threading-dislocation-free ZnO homoepitaxial films by 3d transition-metal
doping”, Appl. Phys. Lett. 108, 021904 (2016).

11.

T. Yamazaki, K. Shigematsu, Y. Hirose, S. Nakao, I. Harayama, D. Sekiba, T. Hasegawa,Amorphous ZnOxNy thin films with high electron Hall mobility exceeding 200 cm2 V-1 s-1, Appl.
Phys. Lett., 109, 262101 (2016).

12.

I. Harayama, K. Nagashima, Y. Hirose, H. Matsuzaki, D. Sekiba, Development of dE-E telescope
ERDA with 40 MeV 35Cl7+ beam in MALT in the University of Tokyo optimized for analysis of70metal oxynitride thin films, Nuclear Instruments and Methods in Physics Research Section B:
Beam Interactions with Materials and Atoms, Volume 384 (2016) 61-67.
13.

T. Onozuka, A. Chikamatsu, T. Katayama, Y. Hirose, I. Harayama, D. Sekiba, E. Ikenaga, M.
Minohara, H. Kumigashira, T. Hasegawa, Reversible resistance modulation induced by fluorine
substitution in perovskitenickelate NdNiO2 thin films, ACS Appl. Mater. Interfaces, 9, 1088210887 (2017).

14.

K. Kawahara, A. Chikamatsu*, T. Katayama, T. Onozuka, D. Ogawa, K.Morikawa, E. Ikenaga, Y.
Hirose, I. Harayama, D. Sekiba, T. Fukumura, T. Hasegawa, Topotactic fluorination of perovskite
strontium ruthenate thin films using polyvinylidene fluoride CrystEngComm, 19 (2017) 313-317.

15.

D. Sekiba, K. Chito, I. Harayama, Y. Watahiki, S. Ishii, K. Ozeki, Installation of high-resolution
ERDA in UTTAC at the University of Tukuba: Determination of the energy resolution and thedetection limit for hydrogen, Nuclear Instruments and Methods in Physics Research Section B:
Beam Interactions with Materials and Atoms, Volume 401 (2017) 29-32.

16.

Eiji Kita, Kenichi Shibata, Yuji Sasaki, Mikio Kishimoto, and Hideto Yanagihara, Magnetic
anisotropy in spherical Fe16N2 core–shell nanoparticles determined by torque measurements,
AIP Advaces, 7, 056212 (5 pages) (2017).

17.

doi.org/10.1063/1.4974276

H. Latiff, M. Kishimoto, S. Sharmin, E. Kita, H. Yanagihara, Effect of Copper Substitution on
Fe3O4 Particles Prepared via Coprecipitation and Flux Methods, IEEE TransMAG, 53 No. 1(2017) 9400104 (4pages).

DOI: 10.1109/TMAG.2016.2596291

71

6.2

Reviews and books

1.

笹 公和、入門講座

精密同位体分析「加速器質量分析装置の原理」、日本分析化学会学

会誌「ぶんせき」2016 年 6 月号（2016）196-202.
S. F. Chichibu, H. Miyake, K. Hiramatsu, and A. Uedono, “Impacts of Dislocations and Point

2.

Defects on the Internal Quantum Efficiency of the Near-Band-Edge Emission in AlGaN-Based DUVLight-Emitting Materials”, III-Nitride Ultraviolet Emitters: Technology and Applications, Springer
Series in Materials Science 227, 115-136 (2016). [10.1007/978-3-319-24100-5_5]

6.3

Proceedings

1.

S. Ishibashi and A. Uedono, “Computational studies of positron states and annihilation parameters insemiconductors − vacancy-type defects in group-III nitrides −”, J. Phys.: Conf. Ser. 674, 012020(110) (2016). [doi:10.1088/1742-6596/674/1/012020]

6.4

Poster or oral presentations at academic meetings

1.

S. Suzuki, “Development of time-of-flight detector for mass measurements of short-lived nuclei
with the rare-RI ring", International Symposium on Neutron Star Matter (NSMAT2016), 21-24
November 2016. (Poster).

2.

森口哲朗、”筑波大学 12UD ペレトロンタンデム加速器の廃止措置”、第 29 回タンデム加速器及びその周辺技術の研究会、筑波大学、2016/06/30-07/01.（口頭発表）

3.

T.Moriguchi, “Density Distributions of 11Li Deduced from Reaction Cross Section
Measurements”, The International Nuclear Physics Conference(INPC)2016, Adelaide Convention
Centre, Australia, 2016/09/11-16. (Poster)

4.

T.Moriguchi, “Density distribution of 14Be from reaction cross-section measurements”., Nuclear
chemistry 2016, Hilton San Antonio Airport, San Antonio, Texas, USA, 2016/12/08-09. (Invited,
Oral presentation)

5.

木村創大、“Precision mass measurements of proton-rich nuclei in A〜60−80 region with themultireflection time-of-flight mass spectrometer”第 9 回 停止・低速不安定核ビームを用いた
核分光研究会（2017 年 3 月、原子力機構）.（口頭発表）

6.

S. Suzuki, “Development of Secondary Electron Time Detector for Ion Beams”, International
Nuclear Physics Conference (INPC2016), Adelaide Convention Center, Australia, 11-26 September
2016. (Oral presentation)

72

7.

向井もも、“Development of low-background gas-counter for the beta spectroscopy at KISS”第
9 回 停止・低速不安定核ビームを用いた核分光研究会（2017 年 3 月、原子力機構）.（口
頭発表）

8.

T. MATSUNAKA, K. SASA, T. TAKAHASHI, M. MATSUMURA, K. SUEKI, A. GOTO,T.

WATANABE, Y. TUCHIYA, N. HIRANO, M. KURI, M. TAKAHASHI, K. KAZAHAYA, I.
MIYAGI AND H. MATSUZAKI, Decrease of iodine isotope ratio observed in crater lake andgeothermal area at Zao volcano, Japan, Goldschmidt2016, Pacifico Yokohama, Yokohama, 26 June1 July, 2016.
9.

Y. SATOU, K. SUEKI, K. SASA, I. NAKAI, Y. ABE, Y. IIZAWA, T. ONO, K. ADACHI AND Y.
IGARASHI, Overview of the radioactive particles in the Fukushima accident, Goldschmidt2016,
Pacifico Yokohama, Yokohama, 26 June-1 July, 2016.

10.

M. HONDA, K. SUEKI, R. TOMITA, A. SAKAGUCHI, K. SASA, Analysis for chlorine and iodine
in natural samples by SEC coupled with ICP-QQQ, Goldschmidt2016, Pacifico Yokohama,
Yokohama, 26 June-1 July, 2016.

11.

Kimikazu Sasa, Tsutomu Takahashi, Tetsuya Matsunaka, Masumi Matsumura, Seiji Hosoya, Maki
Honda, Keisuke Sueki, Mark Stodola, Mark Sundquist, Isobar separation performance of the
Tsukuba 6 MV AMS system, 12th European Conference on Accelerators in Applied Research andTechnology (ECAART12) , Jyväskylä, Finland on 3 - 8 July 2016.

12.

Seiji Hosoya, Kimikazu Sasa, Tetsuya Matsunaka, Masumi Matsumura, Tsutomu Takahashi, Mark
Sundquist, Mark Stodola, Keisuke Sueki, Optimization of ΔE -E detector for 41Ca AMS
measurement using PHITS code simulation, 12th European Conference on Accelerators in Applied
Research and Technology (ECAART12) , Jyväskylä, Finland on 3 - 8 July 2016.

13.

A. Yamazaki, K. Sasa, S. Ishii, M. Kurosawa, S. Tomita, S. Shiki, G. Fujii, M. Ukibe, M. Ohkubo,
A. Uedono, E. Kita, Development of the microbeam PIXE system for additive light elements instructural materials, 15th International Conference on Nuclear Microprobe Technology andApplications (ICNMTA) ( IMP-CAS Lanzhou, China), 31July－5August, 2016.

14.

Kimikazu Sasa, Akiyoshi Yamazaki, Shigeo Tomita, Masanori Kurosawa, Satoshi Ishii, Hiroshi
Naramoto, Masao Sataka, Hiroshi Kudo, Eiji Kita, Akira Uedono, Construction of an Ion Beam
Analysis Facility for Structural Materials at the University of Tsukuba, 2nd International Symposiumfor Innovative Measurement and Analysis for Structural Materials (SIP-IMASM2016), AIST
Tsukuba Campus, Japan, 27-28 Sep., 2016.

73

15.

A. Yamazaki, K. Sasa, S. Ishii, M. Kurosawa, S. Tomita, S. Shiki, G. Fujii, M. Ukibe, M. Ohkubo,
A. Uedono, E. Kita, Present Status of Development of the Ion Microbeam System for Additive Light
Elements in Structural Materials at the University of Tsukuba, 2nd International Symposium for
Innovative Measurement and Analysis for Structural Materials (SIP-IMASM2016), AIST TsukubaCampus, Japan, 27-28 Sep., 2016.

16.

松中哲也, 笹公和, 高橋努, 松村万寿美, 末木啓介, 富田涼平, 恩田裕一, 石丸隆, 谷口圭輔, 脇山義史, 松崎浩之「福島の河川と沿岸海洋環境における 129I/137Cs 比から推察される
放射性のヨウ素とセシウムの挙動」平成 28 年度北関東支部「若手研究者発表会」, 東海,
2016.4.15.

17.

松中哲也、笹公和、高橋努、松村万寿美、末木啓介、富田涼平、恩田裕一、石丸隆、谷口圭輔、脇山義史、松崎浩之，「福島の土壌圏・水圏における 129I/137Cs 分布から推測される
放射性ヨウ素と放射性セシウムの挙動 」、第 53 回アイソトープ・放射線研究発表会、2016
年 7 月 6 日(水)～7 月 8 日(金)、東京大学弥生講堂（東京都文京区弥生 1-1-1）

18.

笹 公和，石井 聰, 大島弘行, 高橋 努, 田島義一, 大和良広, 関場大一郎,
高正雄, 楢本 洋, 工藤 博, 松村万寿美, 山崎明義,

森口哲朗, 左松中哲也, 喜多英治, 上殿明良，筑波大学タンデム加速器施設 UTTAC の現状（2015 年度），‐稼働を開始した 6 MV タンデム加速器によるイオンビーム利用研究の展望‐，「第 29 回タンデム加速器及びその周辺技術の研究会」，2016 年 6 月 30 日（木）～7 月 1 日（金），筑波大学 大学会館
19.

森口 哲朗，笹 公和, 大島弘行, 石井 聰, 高橋 努, 田島義一, 大和良広, 関場大一郎, 喜多英治, 上殿明良筑波大学 12UD ペレトロンタンデム加速器の廃止措置，「第 29 回タンデ
ム加速器及びその周辺技術の研究会」，2016 年 6 月 30 日（木）～7 月 1 日（金），筑波大
学 大学会館

20.

山崎 明義，笹 公和, 石井 聰, 黒澤正紀, 冨田成夫, 上殿明良，筑波大学 6MV タンデム加速器マイクロビームラインの整備状況，「第 29 回タンデム加速器及びその周辺技術の研究会」，2016 年 6 月 30 日（木）～7 月 1 日（金），筑波大学 大学会館

21.

松村 万寿美，笹 公和, 松中哲也, 高橋 努, 細谷青児, 末木啓介，筑波大学 6MV タンデム加速器による I-129 測定の性能評価‐TSUKUBA_I-129 STD 作製に向けて‐，「第 29 回
タンデム加速器及びその周辺技術の研究会」，2016 年 6 月 30 日（木）～7 月 1 日（金），筑波大学 大学会館

22.

細谷 青児, 笹 公和, 高橋 努, 松中哲也, 松村万寿美, 末木啓介, 36Cl-AMS 測定に向けた，
妨害核種 36S 除去の検討，「第 29 回タンデム加速器及びその周辺技術の研究会」，2016 年
6 月 30 日（木）～7 月 1 日（金），筑波大学 大学会館

74

23.

松中 哲也, 笹 公和, 細谷青児, 高橋 努, 松村万寿美, 末木啓介，ガスイオン源を用いた
迅速 14C 測定法の検討，「第 29 回タンデム加速器及びその周辺技術の研究会」，2016 年
6 月 30 日（木）～7 月 1 日（金），筑波大学 大学会館

24.

椎名 陽子，木下 亮, 松田 誠, 今井 誠, 川面 澄, 左高正雄, 笹 公和, 冨田成夫，高速クラスター照射におけるコンボイ電子収量の標的膜厚依存性，「第 29 回タンデム加速器及びその周辺技術の研究会」，2016 年 6 月 30 日（木）～7 月 1 日（金），筑波大学 大学会
館

25.

笹 公和，石井 聰，大島 弘行，高橋 努，田島 義一，大和 良広，関場 大一郎，森口 哲
朗，喜多 英治，上殿 明良，筑波大学複合タンデム加速器施設の現状報告，第 13 回日本
加速器学会年会，2016 年 8 月 8 日(月) ～ 10 日(水)，幕張メッセ国際会議場

26.

笹 公和，Stodola Mark，Sundquist Mark，複合イオンビーム利用研究の展開を目指した 6
MV タンデム型静電加速器の開発，第 13 回日本加速器学会年会，2016 年 8 月 8 日(月) ～10 日(水)，幕張メッセ国際会議場

27.

黒尾奈未，笹公和，細谷青児，松中哲也，6MV タンデム型静電加速器におけるビーム輸
送設定条件の検討，第 13 回日本加速器学会年会，2016 年 8 月 8 日(月) ～ 10 日(水)，幕張メッセ国際会議場

28.

椎名陽子，木下亮，松田誠，今井誠，川面澄，左高正雄，笹公和，冨田成夫，炭素薄膜への高速クラスターイオン照射における 0 度電子分光 I，日本物理学会 2016 年秋季大会，
2016 年 9 月 13-16 日，金沢大学

29.

佐藤志彦，末木啓介，笹公和，福島第一原発北西部における放射性物質と放射性粒子の関係，2016 日本放射化学会年会・第 60 回放射化学討論会，2016 年 9 月 10 日～12 日，新潟大学五十嵐キャンパス30.

松中 哲也, 笹 公和, 細谷 青児, 高橋 努, 松村 万寿美, 末木 啓介，CO2 ガスイオン源を用いた迅速 14C-AMS の開発，2016 日本放射化学会年会・第 60 回放射化学討論会，2016 年
9 月 10 日（土）～12 日（月），新潟大学五十嵐キャンパス

31.

富田涼平，松中哲也，本多真紀，佐藤志彦，松村万寿美，高橋努，坂口綾，松崎浩之，笹公和，末木啓介，福島原発事故以降の 河川 における溶存態と底質土のセシウム同位体比
変化，2016 日本放射化学会年会・第 60 回放射化学討論会，2016 年 9 月 10 日～12 日，新潟大学五十嵐キャンパス

32.

黒澤正紀，笹公和，石井聰，対馬花崗岩の流体包有物中のチタン濃度，日本鉱物科学会年会，2016 年 9 月 23 日～25 日，金沢大学

75

33.

池端 慶，服部浩一，黒澤 正紀，小室光世，笹 公和，石井 聰，三好陽子，島田和彦，戸塚修平，石橋純一郎，中部沖縄トラフ伊平屋北海丘熱水域に産する黄鉄鉱の 微 量元素組
成の特徴，日本火山学会 2016 年度秋季大会学術講演会，2016 年 10 月 13 日～15 日，富士吉田市民会館富士山ホール（山梨県富士吉田市）

34.

笹 公和，左高 正雄，楢本 洋，工藤 博，低 LET 加速粒子による放射線耐性試験のための宇宙用素子照射装置の開発，日本原子力学会 2016 年秋の大会，2016 年 9 月 7 日〜9 日，
福岡県久留米シティプラザ35.

細谷 青児，笹 公和，高橋 努，松中 哲也，松村 宏，松村 万寿美，末木 啓介，難測定
核種 41Ca の加速器質量分析法による超高感度測定 ，日本原子力学会 2016 年秋の大会，
2016 年 9 月 7 日〜9 日，福岡県久留米シティプラザ36.

末木 啓介，佐藤 志彦，笹 公和，福島第一原発から北西地域における放射性核種と放射性粒子，日本放射線安全管理学会 第 15 回学術大会，2016 年 11 月 30 日〜12 月 2 日，岡
山大学

37.

松村万寿美, 笹 公和, 松中 哲也, 末木 啓介, 高橋 努, 渡邊 雅也, 松崎 浩之, 福島第一原子力発電所事故前後における降水中のヨウ素 129 濃度の推移，日本放射線安全管理学会
第 15 回学術大会，2016 年 11 月 30 日〜12 月 2 日，岡山大学

38.

村上道夫，韮澤貴夫，吉兼隆生，末木啓介，笹公和，芳村圭，仮想的な原子力発電所事故
における飲食物由来の被ばく量と希釈率の推定，2016 年度第 29 回日本リスク研究学会年次大会，2016 年 11 月 25～27 日，大分市

39.

ホルトホール大分

笹 公和，宇宙線生成核種の超高感度検出を実現する 6 MV タンデム加速器質量分析装置，
第 2 回 TIA 光・量子計測シンポジウム- 光・量子が繋ぐ TIA 計測連携

~新しい科学と産業の創製をめざして~，2016 年 11 月 10 日，つくば国際会議場 2F 中会議室
40.

201B 202

山崎明義, 笹公和, 石井聰, 黒澤正紀, 冨田成夫, 椎名陽子, 楢本洋, 左高正雄, 工藤博,
志岐成友, 藤井剛, 浮辺雅宏, 大久保雅隆, 上殿明良, 喜多英治，筑波大学 6MV タンデム加速器イオンマイクロビームシステムの整備状況，第 2 回 TIA 光・量子計測シンポジウム-

光・量子が繋ぐ TIA 計測連携

~新しい科学と産業の創製をめざして~，2016 年 11 月

10 日，つくば国際会議場 2F 中会議室
41.

201B 202

中本尚樹, 新田紀子, 土田秀次, 冨田成夫, 笹（ポスター）

公和，平田浩一, 平野貴美, 山田圭介, 千葉敦也, 斎藤勇一, 鳴海一雅，
高速 C60 フラーレンイオンビーム照射による GaSb 表面改質，
高知工科大学 総合研究所ナノテク研シンポジウム 2016，2016 年 11 月 12 日，高知工科大学 永国寺キャンパス

76

42.

Y. Shiina, R. Kinoshita, M. Matsuda, M. Imai, K. Kawatsura, M. Sataka, K. Sasa1, and S. Tomita,
Target thickness dependence of convoy electron yield observed in fast cluster ion bombardment on
thin foils, 第17回「イオンビームによる表面・界面」特別研究会，2016年１２月３日~４日
京都府立大学43.

笹 公和，「最新の加速器質量分析装置が拓く多核種 AMS による高精度年代測定の展望」(招待講演)，「高精度年代測定の地平−AMS と樹木年輪−」第 19 回日本 AMS シンポジウ
ム（JAMS-19）・2016 年度「樹木年輪」研究会 共同開催シンポジウム、2016 年 12 月 17
－18 日，国立歴史民俗博物館

44.

講堂

細谷青児，笹公和，高橋努，松中哲也，松村万寿美，末木啓介，41Ca-AMS の実用化に向けた技術開発と測定評価，第 19 回日本 AMS シンポジウム（JAMS-19），2016 年 12 月
17－18 日，国立歴史民俗博物館

45.

講堂

本多真紀，高久雄一郎，大野剛，角田伸一郎，鹿籠康行，松崎浩之，坂口綾，笹公和，高橋努，松中哲也，松村万寿美，細谷青児，末木啓介，AMS とコリジョン/リアクションセ
ル ICP-MS による環境試料中の 129I の分析，第 19 回日本 AMS シンポジウム（JAMS-19），
2016 年 12 月 17－18 日，国立歴史民俗博物館

46.

講堂

稲葉留衣，坂口綾，野村知哉，山川茜，山野博哉，佐々木圭一，渡邊剛，Peter Steier，本多真紀，笹公和，松中哲也，細谷青児，高橋努，松村万寿美，末木啓介，サンゴコア分析
による長寿命人工放射性核種の日本海導入履歴復元の試み，第 19 回日本 AMS シンポジウ
ム（JAMS-19），2016 年 12 月 17－18 日，国立歴史民俗博物館

47.

講堂

松村万寿美，笹公和，松中哲也，高橋努，細谷青児，末木啓介，筑波大学におけるヨウ素
129 標準試料作製計画，第 19 回日本 AMS シンポジウム（JAMS-19），2016 年 12 月 17－
18 日，国立歴史民俗博物館

48.

講堂

Hongtao Shen, Jiang Shan, Kimikazu Sasa, Masumi Matsumura, Tetsuya Matsunaka, Tsutomu
Takahashi, Seiji Hosoya, Keisuke Sueki, Study on 36Cl-AMS for Exposure Age Dating of Guangxi
Tiankeng, 第 19 回日本 AMS シンポジウム（JAMS-19）, 2016 年 12 月 17－18 日，国立歴
史民俗博物館

49.

講堂

松中哲也，笹公和，高橋努，細谷青児，松村万寿美，末木啓介，佐藤志彦，東日本原子力施設周辺の年輪内における 1960 年以降の炭素 14 濃度変動，第 19 回日本 AMS シンポジ
ウム（JAMS-19），2016 年 12 月 17－18 日，国立歴史民俗博物館

50.

講堂

末木啓介，松尾一樹，太田裕貴，本多真紀，坂口綾，笹公和，松中哲也，高橋努，細谷青児，松村万寿美，佐藤志彦，福島事故由来の放射性物質における長寿命核種の AMS 測定，

77

第 19 回日本 AMS シンポジウム（JAMS-19），2016 年 12 月 17－18 日，国立歴史民俗博物
館
51.

講堂

松中 哲也，笹 公和，高橋 努，細谷 青児，松村 万寿美，末木 啓介，佐藤 志彦，東海
原子力施設の稼働状況に応答した樹木年輪内の炭素 14 濃度変動，第 18 回「環境放射能」
研究会，2017 年 3 月 14～ 3 月 16 日

52.

細谷青児, 笹公和, 松中哲也, 高橋努, 松村万寿美, Hongtao Shen, 末木啓介「長寿命放射性核種 36Cl の加速器質量分析法による超高感度測定」，第 18 回「環境放射能」研究会, つ
くば, 2017.3.14-16.

53.

笹 公和，加速器質量分析法による長寿命放射性核種の超高感度検出技術の進展とその応用（招待講演），第 18 回「環境放射能」研究会, つくば, 2017.3.14-16.

54.

新田紀子, 中本尚樹, 土田秀次, 冨田成夫, 笹公和，平田浩一, 平野貴美, 山田圭介, 千葉敦也, 斎藤勇一, 鳴海一雅，高速 C60 フラーレンイオンビーム照射による GaSb への照射効果，日本金属学会、2017 年春期(第 160 回)講演大会，首都大学東京南大沢キャンパス，2017 年 3 月 15 日(水)～3 月 17 日(金)55.

細谷青児, 笹公和, 高橋努, 松中哲也, 松村万寿美, Hongtao Shen, 末木啓介，加速器質量分
析法における 10Be, 36Cl の高感度測定のための同重体分離手法の検討とその測定性能評価，
日本原子力学会 2017 年春の年会, 東海大学湘南キャンパス, 2017. 3. 27-29.

56.

笹 公和，山崎明義，石井 聰，黒澤正紀，冨田成夫，左高正雄，楢本 洋，工藤 博，構造
材料計測用イオンビーム分析装置の開発，日本原子力学会 2017 年春の年会, 東海大学湘南キャンパス, 2017. 3. 27-29.

57.

Hawa Latiff, M. Kishimoto, S. Sharmin, H. Yanagihara, E. Kita
“Synthesis and physical properties of single phase cubic and tetragonal CuFe2O4 particles”,
International Conference on Fine Particle Magnetism(ICFPM) 2016, Washington DC, USA, June
13-17, 2016

58.

E. Kita, Y. Sasaki, M. Kishimoto and H. Yanagihara,“Magnetic Anisotropy in spherical Fe16N2 core-shell nanoparticles determined by torquemeasurements”, 61st Annual Conference on Magnetism and Magnetic Materials (MMM2016), New
Orleans, Louisiana, October 31 – November 4, 2016,

78

6.5

UTTAC seminars

2016
May 26 Measurement of 1st, 2nd and 3rd azimuthal anisotropy in Cu+Au collisions, Hiroshi Nakagomi(University of Tsukuba)2017
Jan 13

Direct photon - hadron azimuthal correlation in 7 TeV pp collisions at LHC-ALICE experiment,
Kyoichiro Ito (University of Tsukuba)
High pT hadron measurement with SVTX in 200 GeV 3He+Au collisions at RHIC-PHENIX
experiment, Sakiko Kudo (University of Tsukuba)
Pi0 measurement with EMcal in 5.02 TeV pp collisions at LHC-ALICE experiment, Ryohei
Koyama (University of Tsukuba)
Multiplicity dependence of long-range azimuthal correlation in 510 GeV pp collisions at RHICPHENIX experiment, Yusuke Fukuda (University of Tsukuba)
Performance of EMcal for pi0 measurement in 5.02 TeV Pb+Pb collisions at LHC-ALICE
experiment, Kazunari Matsunaga (University of Tsukuba)
Jet measurement with EMcal in 5.02 TeV Pb+Pb collisions at LHC-ALICE experiment, Byung
Chul Kim (University of Tsukuba)

Jan 16

New aspects of nuclear physics probed by reaction cross sections, Mitsunori Fukuda (Osaka
University)

Mar 16 Lecture on high energy ion microbeams, Dr. Geoffrey Grime (Senior Researcher, The Surrey Ion
Beam Centre, University of Surrey, United Kingdom)

79

6.6

Symposium
The 29th Community Meeting on the Electrostatic Particle Accelerators
and Their Related Technologies
30 Jun – 1 July 2016
University Hall, University of Tsukuba

1. Welcome address : Akira Uedono (University of Tsukuba)
2. Welcome address : Kimikazu Sasa (University of Tsukuba)
3. Status Report of the Tandem Accelerator Facility at the University of Tsukuba (FY 2015) - Future
Prospects of Ion Beam Applications on the Newly Started 6 MV Tandem Accelerator - : Kimikazu Sasa
(University of Tsukuba)
4. Status report of the NIES-TERRA : Toshiyuki Kobayashi (Center for Environmental Measurement andAnalysis, NIES)
5. Current status of MALT, The University of Tokyo : Chuichiro Nakano (The University Museum, The
University of Tokyo)
6. Current status of Compact AMS at UMUT (2015-16) : Hiromasa Ozaki (The University Museum, The
University of Tokyo)
7. Current status of the Single Stage AMS at AORI, The University of Tokyo : Takahiro Aze (Atmosphereand Ocean Research Institute, The University of Tokyo)
8. Induction microtorn for semi-relativistic large cluster ions: Ken Takayama (High Energy Accelerator
Research Organization)
9. Present status of the tandem accelerator facility at Kyushu University-- Decommissioning of Hakozaki
facility and construction of Ito facility -- : Tetsuo Noro (Faculty of Science, Kyushu University)
10. Decommissioning of the 12UD Pelletron tandem accelerator : Tetsuaki Moriguchi (University ofTsukuba)
11. A report of measurement of neutron emission in electrostatic accelerator facilities : Kazuyoshi

Masumoto (High Energy Accelerator Research Organization)
12. Present status of the tandem accelerator at the JAEA-AMS-TONO (2015) : Natsuko Fujiata (Tono
Geoscience Center, JAEA)
13. Present status of JAEA-Tokai tandem accelerator facility : Kenichi Kutsukake (Tandem Accelerator
Section, Department of Research Reactor and Tandem Accelerator, Nuclear Science Research Institute,Japan Atomic Energy Agency)
14. Current status of the compact-AMS system at Paleo Labo Co., Ltd.(2016) : Shigeru Itoh (AMS Dating
Facility, Paleo Labo Co., Ltd.)
15. Progress report of NIRS electrostatic accelerator facility (PASTA & SPICE) : Masakazu Oikawa(National Institute of Radiological Science, National Institute for Quantum and Radiological Scienceand Technology)
16. Present Conditions of Tandem Accelerator in Kobe University 2016 : Akira Taniike (Graduate Schoolof Maritime Sciences, Accelerator Division of Center for Supports to Research and Education Activities,

80Kobe University)
17. Present Status of Tohoku Microbeam System : Shigeo Matsuyama (Tohoku University)
18. Status of Tohoku University Dynamitoron Accelerator : Misako Miwa (Tohoku University)

19. Present status of YU-AMS 2015-2016 : Toru Moriya (Center for Accelerator Mass Spectrometry,
Yamagata Univ.)
20. Construction and trial operation of the Ion Microbeam System on the 6 MV Tandem Accelerator at the
University of Tsukuba : Akiyoshi Yamazaki (Faculty of Pure and Applied Sciences, University ofTsukuba)
21. Current status of tandem accelerator ion analyzing equipment at NIFS : Akimitsu Nishizawa(Pesco Co. Ltd.)
22. Present status and application studies with AMS 14C system at Nagoya University (2016) : Toshio
Nakamura (Institute for Space-Earth Environmental Research, Nagoya University)
23. Progress report of tandem accelerator in NWU : Jyunya Karimata (Research Cooperation Division,
Nara Women’s University)
24. Status report of the accelerator facility at the Department of Nuclear Engineering, Kyoto University (FY2015) : Yoshitaka Sasaki (Department of Nuclear Engineering, Kyoto University)
25. Current status of the accelerator facility at The Wakasa Wan Energy Research Center : Satoshi Hatori(The Wakasa Wan Energy Research Center)
26. Development of the electric charge conversion model negative ion source : Hiroaki Yamada (The
Wakasa Wan Energy Research Center)
27. SF6 gas recovery system that adds a Low-temperature adsorption : Tetsuya Odagiri (The Wakasa Wan
Energy Research Center)
28. Development of a C60 fullerene ion source using sublimation and electron-capture ionization : Koshiro
Nakamura (Tokyo Institute of Technology)
29. Startup Status of the 1.7MV Tandem Pelletron Accelerator at Tokyo City University : Naoto Hagura(Atomic Energy Research Laboratory / Tokyo City University)
30. Present status of the Neutron exposure accelerator for biological effects : Noriyoshi Suya (National
Institutesfor Quantum and Radiological Science and Technology NIRS)
31. Construction of an AMS beam line at the Kyushu University tandem accelerator facility : Toshiya
Hataguchi (Faculty of Sciences, Kyushu University)
32. Conditioning of the 5-MV Electrostatic Accelerator in the JAEA-AMS-TONO : Akihiro. Matsubara(PESCO CO., Ltd.)
33. Current status of CAMS system at NIES : Yumi Osonoi (Center for Global Environmental Research,
NIES)
34. Current status of electrostatic accelerators at TIARA : Yoshimi Hirano (Takasaki Advanced
Radiation Research Institute, QST)
35. Current Intensification of Fullerene Ion Beam : Atsuya Chiba (Takasaki Advanced Radiation ResearchInstitute, QST)
36. The performance evaluation of the measurement of iodine-129 by the 6 MV Tandem

Accelerator at the University of Tsukuba‐Looking forward to preparation of TSUKUBA_I-129

81

standards for AMS‐ : Masumi Matsumura (Accelerator Mass Spectrometry Group , University ofTsukuba)
37. Study of interference nuclide 36S removal for 36Cl-AMS measurement : Seiji Hosoya (Accelerator
Mass Spectrometry Group , University of Tsukuba)
38. Development of rapid 14C-AMS using CO2 gas ion source : Tetsuya Matsunaka (AMS Group, Universityof Tsukuba)
39. Target thickness dependence of convoy electron yield observed in fast cluster ion bombardment on thinfoils : Yoko Shiina (University of Tsukuba)
40. Concluding remarks : Tetsuaki Moriguchi (University of Tsukuba)

82

7.
THESES

Doctor theses
Isao Harayama

Development of an advanced ERDA and PIXE system for analyses offunctional films

Master theses
Toaki Kakizaki

Free volume evaluation of epoxy resin for CFRP by positron annihilation
methodShunya Sakai

Construction of light irradiation system by positron annihilation method andcharacterization of GaN by light irradiation

Takahiro Tamura

Development of dual MCP coincidence system in high-resolution ERDA for
sensitive hydrogen analysis

Eri Noguchi

Observation of oxygen vacancies and Ti interstitials on the surface of
Rutile-TiO2(110) by high-resolution RBS

Undergraduate theses
Junichi Kikuda

Observation of He2+ channeling for Pd(110) by RBS

Yuki Sugisawa

Development of strip-SSD for high-sensitivity ERDA

Kaoru Sako

Free volume evaluation of resin for CFRP by positron annihilation

Shusuke Hashimoto

Defect evaluation of ion implanted Ge by positron annihilation

Yuya Asai

Development of Time Dependent Doppler Spreading Measurement Systemand Defect Evaluation of GaN on Si

Rui Inaba

Temporal variation of anthropogenic 129I in the Japan Sea using a coral
core sample

Yuki Ota

Quantitative determination of 36Cl from soil near the Fukushima Daiichi
Nuclear Power Plant with the use of AMS

Kazuki Matsuo

Characterization of radioactive particles derived from the Fukushima Daiichi
Nuclear Power Plant accident

Daiki Kamioka

Developments of time-of-flight detector using secondary electrons from thin
foil

83

8.
LIST OF PERSONNEL

Tandem Accelerator Complex
A. Uedono

Director, Professor

K. Sasa

Associate Professor

D. Sekiba

Lecturer

T. Moriguchi

Assistant Professor

H. Oshima

Electrical Engineer

Y. Tajima

Mechanical Engineer

S. Ishii

Mechanical Engineer

T. Takahashi

Electrical Engineer

Y. YamatoElectrical Engineer

M. Sataka

Research Fellow

M. Matsumura

Research Supporter

M. Ohyama

Administrative Staff (2016.4.1−2016.6.30)

S. Kuramochi

Administrative Staff (2016.7.1−2017.3.31)

M. Satoh

Administrative Staff

I. Takada

Administrative Staff

Research Members1
Division of Physics
A. Ozawa

T. Matsunaka

S. Suzuki

H. ShenT. Moriguchi

K. Sasa

S. Sharmin

S. Tomita

Division of Applied Physics
E. Kita

D. Sekiba

A. Uedono

H. Yanagihara

Division of Geoscience
M. Kurosawa
Division of Chemistry
K. Sueki

A. Sakaguchi

Division of Information and Systems
T. Kameda

1

The “research members” include the authors and coauthors within 5 years back from this fiscal year, as well as themembers of research projects running at UTTAC.

84

Staff of Open Advanced Facilities Initiative
H. KudoH. Naramoto

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

F. Arai

S. Fukuoka

I. Harayama

Y. Shiina

S. Kimura

M. MukaiM. Honda

Y. LiuR. PatelH. Latiff

Y. Hisamatsu

M. Matsumoto

E. Noguchi

S. NomotoT. Tamura

R. Tomita

T. Tainosho

M. Amano

S. Hosoya

T. Kakizaki

S. SakaiN. Yamamoto

N. Kuroo

T. Eguchi

Y. Hosoi

H. Onoda

K. Tsujita

D. Kamioka

K. Sako

K.Nakayama

S. Hashimoto

J. Kikuda

R. Inaba

Y. OtaK. Hattori

K. Matsuo

Y. Sugisawa

K. OyaA. Nagata

A. Yasuda

H. Watanabe

Undergraduates

Scientific Guests and Fellows
Y. Tosaki

National Institute of Advanced Industrial Science and Technology (AIST)

H. Matsumura

High Energy Accelerator Research Organization (KEK)

N. Kinoshita

SHIMIZU Corporation

K. Hirata

National Institute of Advanced Industrial Science and Technology (AIST)

T. Omori

The University of Tokyo

R. Katayama

The University of Tokyo

K. Ozeki

Ibaraki University

2

Also, a staff of Open Advanced Facilities Initiative85