UTTAC-83, 2014

UTTAC
ANNUAL REPORT 2013

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

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

UTTACANNUAL REPORT 2013
April 1, 2013 – March 31, 2014

UTTAC-83, 2014

Executive Editor: Eiji Kita
Editors: Hiromi Kimura, Tetsuaki Moriguchi, Daiichiro Sekiba and Kimikazu Sasa

UTTAC is a series of issues, which include annual reports of
Tandem Accelerator Complex, Research Facility Center
for Science and Technology, University of Tsukuba.
Copyright © 2014 by Tandem Accelerator Complex, Research Facility Center
for Science and Technology, University of Tsukuba and individual contributors.
All reports are written on authors’ responsibility and thus the editors are not liable
for the contents of the report.

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

PREFACE
This annual report covers research conducted at the Tandem Accelerator Complex,
Research Facility Center for Science and Technology, the University of Tsukuba, during fiscal
year 2013 (April 1, 2013–March 31, 2014). After the Great East Japan Earthquake on March 11,
2011, research has been limited to that using the 1 MV Tandetron accelerator and radiation
source experiments, 57Fe Mössbauer spectroscopy, and positron annihilation spectroscopy. The
circumstances of our research have not changed much and are almost the same as those in thelast fiscal year. Thus, this volume has slightly fewer pages than older volumes like one for thelast year.
A new 6 MV tandem-type accelerator with support from the government has reached at
mid of March 2014 from the National Electrostatics Corporation in Middleton, Wisconsin, USA
to the TAC. We are hoping to restart our research activities again after the installation.
The efforts of Open Advanced Facilities Initiative supported by MEXT were continued in thisterm, and the second stage was completed. The government supported additional facilities
related to this program with an extra budget. With this support, our performance on thisprogram is accelerated.
We are really looking forward to operating and reporting on the new 6 MV accelerator.
Editors-i-CONTENTS

1. ACCELERATOR AND FACILITIES
1.1 Accelerator operation 2013 ···········································································

1

1.2 Installation of the 6 MV tandem accelerator ·······················································

3

2. NUCLEAR PHYSICS
2.1 Reaction cross section of 45Sc(p, α)42Ca for basis of silicon burning ···························

5

2.2 The experimental study of the astrophysical S-factor of 6Li(p, γ)7Be reaction ················

8

2.3 Development of a beam monitor detector using a mirror-electric field ························

10

2.4 Test of rotating magnetic field system for β-NMR method ······································

12

3. MATERIAL SCIENCE
3.1 Effect of synthesis conditions on the magnetic properties for ferromagnetic iron oxide
nanoparticles using Mössbauer spectroscopy ······················································ 15
3.2 Conversion electron Mössbauer spectroscopy (CEMS) of cobalt ferrite thin films grownby sputtering using a 57Fe enriched target ··························································

17

3.3 Magnetic states of ion implanted Fe3O4 thin films studied by Mössbauer spectroscopy ·····

19

3.4 Mössbauer study of CoxFe4-xN films grown by molecular beam epitaxy ······················

21

3.5 Cluster effect on the yield of secondary electrons produced by inner shell electron
excitation································································································ 23
3.6 Limit of detection for hydrogen by developed high-resolusion ERDA system ···············

25

4. ACCELERATOR MASS SPECTROMETRY
4.1 Depth profiles of 129I and 129I / 127I ratio in soil at the near-field site of the Fukushima
Dai-ichi Nuclear Power Plant ········································································

29

4.2 Study on monitoring of volcanic activity using 129I / 127I ratios in crater lake and hot springat Zao volcano, Miyagi Prefecture ··································································

31

4.3 Successive searches of

129

I contamination in the chemical sample preparation room ·······

33

4.4 Comparison between 36Cl-AMS simulations using PHITS code and experiments ···········

35

4.5 Distribution of 129I in the environment released from the FDNPP accident and estimationof 131I/129I ratio ·························································································

37

4.6 Technological development for Strontium-90 determination using AMS ·····················

38- iii -

5. LIST OF PUBLICATIONS················································································

39

6. THESES ·········································································································

48

7. SEMINARS ····································································································

49

8. SYMPOSIUM ·································································································

50

9. LIST OF PERSONNEL·····················································································

51- iv -

1.
ACCELERATOR AND FACILITIES1.1

Accelerator operation 2013

K. Sasa, S. Ishii, H. Kimura, H. Oshima, Y. Tajima, T. Takahashi, Y. Yamato,
T. Komatsubara, D. Sekiba and E. Kita
We have operated and maintained the 1 MV Tandetron accelerator and the radio-isotope utilizationequipment in the University of Tsukuba, Tandem Accelerator Complex (UTTAC). In addition, we haveconstructed the 6 MV tandem accelerator instead of the broken 12UD Pelletron tandem accelerator.
The total service time of the UTTAC multi-tandem accelerator facility was 2,064 hours in the fiscal
year 2013. The number of facility users is 106 on campus and 12 outside the campus. 648 hours for the 1
MV Tandetron accelerator and 14 days for the radio-isotope utilization equipment were used for industrial
users under the project "Promotion of Advanced R&D Facility Utilization", which was supported
financially by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of JAPAN. In
the project, a total of 12 research programs were conducted in 2013.
The 1 MV Tandetron accelerator
The operating time and the experimental beam time of the 1 MV Tandetron accelerator were 1357.1
and 798 hours, respectively, during the total service time in 2013. A total of 66 research programs werecarried out and a total of 725 researchers used the 1 MV Tandetron accelerator. Figure 1 shows thepercentage of accelerated ions for the 1 MV Tandetron accelerator. In 2013, H beams accounted for79.2 % of ion acceleration. O beams were mainly used for high-resolution ERDA. Figure 2 shows thepercentage of research fields for the 1 MV Tandetron accelerator in 2013.

Figure 1. Percentage of accelerated ion species for the 1 MV Tandetron accelerator in 2013.

1

Figure 2. Percentage of research fields for the 1 MV Tandetron accelerator in 2013.

2

1.2

Installation of the 6 MV tandem accelerator

K. Sasa, S. Ishii, H. Kimura, H. Oshima, Y. Tajima, T. Takahashi, Y. Yamato,
T. Komatsubara, D. Sekiba and E. Kita
A new tandem accelerator system has been designed and constructed at the University of Tsukuba
after the Great East Japan Earthquake [1, 2]. The accelerator system consists of the 6 MV Pelletron
tandem accelerator, four negative ion sources, a Lam-shift polarized ion source (PIS), a vertical irradiationline and 12 beam lines. A high energy beam transport line connects from the accelerator room to present
experimental facilities at the experimental room. The 6 MV Pelletron tandem accelerator will be applied tomulti-purpose ion beam researches such as AMS, microbeam applications, PIXE analysis for geoscienceand material research, heavy ion RBS/ERDA, nuclear reaction analysis (NRA) for hydrogen in material,high energy ion irradiation for semiconductor and nuclear physics. Figure 1 shows a most recent layout of
the 6 MV tandem accelerator system in the accelerator room.

Figure 1. Layout of the 6 MV tandem accelerator system in the accelerator room.
A high voltage test was already tried with a great deal of success at the National Electrostatics Corp.
(NEC), USA in January, 2014. The generator was operated up to the maximum terminal voltages as highas 6.3 MV. A stability is estimated to be better than 1 kV at 6.0 MV terminal voltage. Maximum beam
currents are estimated up to 50 µA for heavy ions. Figure 1 shows a photograph of setup for thehigh-voltage test at NEC.

3

Figure 1. Photograph of setup for the high-voltage test at NEC, USA in January, 2014.
The main accelerator, the model 18SDH-2 Pelletron accelerator developed by NEC, USA wasinstalled at the University of Tsukuba on 6 March, 2014 (Figures 2 and 3). The accelerator tank was
designed as about 2.74 m in diameter and 10.5 m in length. The high voltage terminal has a longer gas
stripper tube assembly and a foil changer with 80 foil holders for electron stripping of negative ions. At
present, we have constructed ion sources and beam lines. The accelerator operation will start at the fiscal
year 2015.

Figure 2. The accelerator tank was delivered to
Tsukuba on 6 March 2014.

Figure 3. Setup of the accelerator tank in theaccelerator room

References[1] Kimikazu Sasa et al., AIP Conf. Proc. 1533, pp. 184-188; doi: http://dx.doi.org/10.1063/1.4806798.
[2] Kimikazu Sasa et al., UTTAC, ANNUAL REPORT 2012, UTTAC-82, 2013, 3.

4

2.
NUCLEAR PHYSICS

2.1

Reaction cross section of 45Sc(p, α)42Ca for basis of silicon burning

T. Komatsubara 1, T. Onishi, M. Mukai, D. Izumi, Y. Saito, N. Inaba, K. Sawahata, T. Hayakawa2, T.
Shizuma2, H. Yamaguchi3, S. Kubono4, D. Nagae, K. Sasa and A. Ozawa
Silicon burning is a sequence of reactions which create from silicon to iron at the final stage of theevolution of stars. When temperature of stars rise up to be 3 ~ 5 GT by gravitational compression, nuclei
of silicon are starting to be decomposed by thermal photodisintegration and to be protons, neutrons, andα particles. The emitted α particles can fuse with the silicon or heavier nuclei and the continuous fusion
chain reaction can reach to create the iron[1]. Among those of (α, γ) and (p, γ) reactions, the flow ofreactions is predicted to be concentrated on 45Sc, which are 42Ca(α, p)45Sc and 45Sc(p, γ)46Ti reactions[2].
Then we have chosen the reversed reaction of 45Sc(p, α)42Ca to evaluate the forward reaction rate, because
experimental information of the lower energy part of the reaction cross sections was quite limited [3].
Experimental study was carried out by using the 1 MV Tandetron accelerator at UTTAC. Proton beam
having the energy of 1.8 ~ 2.1 MeV was irradiated on the scandium target. The target was 40 µg/cm2 inthickness made with evaporation of metallic scandium on a 53 µg/cm2 carbon foil. Since Q-value of the45

Sc(p, α)42Ca reaction is rather large to be 2.34 MeV the emitted α particles can be determined with E-∆E

counter telescope consisted of two Si detectors.
Thickness of the detectors are 10 µm for the ∆E
counter and 1500 µm for the E counter, respectively.
The thick E detector is necessary to have full stop
proton peak. The detector was located at 49.5 mm(39.5 mm for the additional measurement) having thewindow of φ 7.0 mm diameter.
The measured angular distributions of the emitted α
particle are shown in Fig. 1 for the proton beamenergies of 1.8, 2.0, and 2.1 MeV. The distributions
show rather flat, so that the distribution is assumed to
be isotropic for other bombarding energies.
Calculated astrophysical S-factor S(E) from the4542

measured cross sections for the Sc(p, α) Ca reaction
are shown in Fig. 2 comparing with the previous study

Fig. 1. Angular distribution of 45Sc(p, α)42Ca
reaction.

by Schweitzer[3]. Reported data for the 42Ca(α, p)45Sc
1

Present address: Institute for Basic Science, Yuseong-gu, Yuseong-daero, Daejeon, Republic of Korea
Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki, Japan
3
Center for Nuclear Study, University of Tokyo, Hirosawa 2-1, Wako, Saitama, Japan
4
RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama, Japan2

5

reaction[4] are also consistent within the detailed balance[1] (not shown in this figure). A result of fittingwith multilevel R-Matrix theory SAMMY[5] is also shown by the dashed lines. Parameters used for thefitting is tabulated in Table 1. With this fitting, the two peaks can be assigned as narrow resonances having
spins of 1- and 0+ as shown in Fig. 2. In the previous report[6], a 0+ state was reported at 12.46 MeV with44

Ca(3He, n)46Ti reaction, which can be plausible state corresponding to our observed level at 12.31 MeV.

Since Gamow window can be estimated between 1.8 and 2.4 MeV for the silicon burning, the existenceof the newly observed resonance at 2 MeV can significantly increase the reaction rate. Further continuous
investigations are desirable to explore the astrophysical reaction rate for the silicon burning.
References[1] C.E. Rolfs and W.S. Rodney, “Cauldrons in the Cosmos”, The University of Chicago Press, 1988.
[2] S.E. Woosley et al., Astrophys J.S. 26 (1973) 231.
[3] J.S. Schweitzer et al., Nucl. Phys. A287 (1977) 344.
[4] L.W. Mitchell et al., Nucl. Phys. A443 (1985) 487.
[5] SAMMY-8, Radiation Safety Information Computational Center (RSICC), Oak Ridge National
Laboratory.
[6] “Table of Isotopes, CD ROM Edition”, R.B. Firestone and V.S. Shirley editor, (1996), LBL,
Wiley-Interscience.

Fig. 2. Astrophysical S-factor for the 45Sc(p, α)42Ca reaction. Present results areshown by closed circles. Previous work done by Schweitzer[3] are shown by open
squares. A result of SAMMY R-matrix fit[5] is shown by dashed lines.

6

Table 1. Parameters used for the SAMMY R-matrix fit[5] for the 45Sc(p, α)42Ca reaction as shown in theFig. 2 with the dashed lines. In this fitting, two narrow resonances are obvious shown as peak1 and peak2
in the figure. The Ex denotes the excitation energy of compound nucleus 46Ti. For the calculation of theenergy Ex, a Q value of 10.345 MeV is used for the 45Sc(p, γ)46Ti reaction.

Peak 1
Peak 2

Elab [MeV]
1.731
2.014

Ecm [MeV]
1.693
1.970

Jπ
10+

Γp [keV]
3.6 ± 0.7
0.76 ± 0.02

7

Γα [keV]
1.5 ± 0.1
29 ± 1

Ex [MeV]
12.03
12.31

2.2

The experimental study of the astrophysical S-factor of 6Li(p, γ)7Be reaction

S.Z. Chen 1, J.J He1, T. Komatsubara, S.B. Ma1, S. Kubono 2, K. Sasa, A. Ozawa, A. Yamazaki, T. Onishi,
M. Mukai, D. Izumi, H. Miyatake 3, D. Sekiba, T. Hayakawa 4, T. Shizuma4, D. Kahl 5, C. Moon 6 and T.
Kajino 7
In the low-temperature astrophysics sites, e.g., our Sun, the Red Giant stars and the nova, the Gamow
windows are well below the Coulomb barriers for the charged- particle-induced nuclear reactions involved.
These nuclear reactions occur through the quantum-mechanics barrier penetration, sometimes referred toas the tunneling effect, with a small but finite probability. Because of the exponential behavior of theprobability for tunneling, the reaction cross-section drops rapidly for energies below the Coulomb barrier.
Frequently, the reaction cross-section is expressed as[1]:(1)
The quantity η is called the Sommerfeld parameter and is defined as(2)

In Eq. (1), the function S(E), containing all the strictly nuclear effects, is referred to as the astrophysicalS-factor [1]. In contrast to cross-section, the S-factor is a smoothly varying function of energy for thenon-resonant reactions. With these characteristics, the factor S(E) is much more useful in extrapolating
measured cross-sections at higher energies to Gamow energies.
6

Li(p, γ)7Be reaction and its reverse reaction are closely related to the big bang nucleosynthesis (BBN). It

is worthwhile to determine the low-energy S-factors of 6Li(p, γ)7Be reaction. The measurement of thisreaction has been done on 320 kV high voltage platform in Lanzhou and found an interesting sizable drop
contrary to any existing theoretical expectations at energies below 200 keV [2]. Limited by the energy of
320 kV platform, we cannot cover the interesting energy region of 0.3~1 MeV to compare our data withprevious results. It’s necessary to investigate this reaction on a wider energy region accelerator.
A new measurement has been done on the 1 MeV Tandetron accelerator in the University of Tsukuba. The
experimental setup is similar to the one described in Ref. [2]. The proton beam passed through 2
collimators (each10 mm in diameter) and was focused on the target. The two collimators were located 50
and 100 cm up stream of the target. The solid targets were prepared from 6Li2O material evaporated onto a
0.2 mm thick Ta backing, with a thickness of 36 μg/cm2. A high efficiency HPGe detector(GEM140P4-ST) was placed in close geometry at zero degree with respect to the beam direction. An
ORTEC ULTRA ion-implanted silicon detector was installed at 135°.

8

From equation (1), we can give out the relationship between different energy points of E1, E2:(3)Here, N1, N2 are the counts of clover detector at different energy points, Q1, Q2 are the beam integrationsof different energy points. Using this formula, wenormalized our new experimental data at Ec.m. = 206
keV, which was given in Ref. [2]. The preliminary
result was shown in Fig.1. From plot we can see that
our new data can consist with the previous result inlarge energy region. The little deviation at highenergy point is due to the anisotropic angle
distribution of γ-rays. A deeper analysis is still inprocess. More results will be reported in the future.

Fig.1. preliminary result of 6Li(p, γ)7Be
References[1] C. Rolfs, W. Rodney. Cauldrons in the Cosmos. The University of Chicago Press, 1988.
[2] J.J. He, et al. Phys. Lett. B 725 (2013) 287.
1

Institute of Modern Physics, Lanzhou, Gansu, China
RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
3
High Enegry Accelerator Reseach Oganiation (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801, Japan
4
Japan Atomic Energy Agency, Shirakata Shirane 2-4, Tokai, Ibaraki 319-1106, Japan
5
Center for Nuclear Study, University of Tokyo, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
6
Hoseo University, Chung-Nam 336-795, Korea
7
Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo
181-8588, Japan
2

9

2.3

Development of a beam monitor detector using a mirror-electric field

D. Nagae, Y. Abe, S. Okada, K. Sawahata, Y. Saito, N. Inaba and A. Ozawa
The precision mass measurement system of rare RI is proposed at RIKEN RI beam factory [1]. In
this plan, the mass is deduced from a time-of-flight of RIs in the ring. Details for the principle of themass measurement are described elsewhere [2]. In order to monitor a motion of the stored rare RI in
the ring, a dedicated detector has been developing. Required specifications and performances for themonitor detector are i) the effective area is consisted by thin material and have a large size match a beamsize, ii) separation of the each revolution, and iii) position resolution less than 10 mm. To satisfy suchthe requirements, a beam monitor detector consisting of thin and large carbon foil, Micro Channel Plate(MCP) and using a electrostatic-mirror field has been developing. The principle of the monitor detector isthat a beam generates secondary electrons in passing through a thin carbon foil. The secondary electrons
are accelerated by an acceleration-electric field (Eacc ) which is produced by a potential of carbon foil
(Vfoil ) and that of acceleration grid (Vacc ). Electrons are directed to the mirror-electric field comprising twoparallel grids placed at 45 degree to the ion trajectory. Then they are deflected at 90 degree toward the
MCP by a electrostatic mirror field (Emir ) which is produced by two parallel grids. The electrostatic-mirror
field is express as Emir = Vout −Vin , where Vout and Vin denote a potential for outside grid of parallel gridand that for inside grid of parallel grid. The potential of inside grid is same as that for acceleration grid
(Vacc ). These grids are made of Au + W wires with a diameter of 40 µ m and a pitch distance of 1 mm forthe acceleration grid and that of 3 mm for the two parallel grids. A schematic view of the monitor detector
is shown in Fig. 1. The size and thickness of the carbon foil is 100 mm × 50 mm and 60 µ g/cm2 .
Parallel grid(Vin,Vout)Acceleration grid
(Vacc)

Ion Beam

Carbon-Foil (60 µg/cm2)(Vfoil)e-

MCP

Fig. 1. Schematic layout of the monitor detector

An experiment to evaluate a performance of the detector was performed at SB2 beam line [3] in
HIMAC. The experimental setup is shown in Fig. 2. 84 Kr beam (∼ 170 MeV) was transported to thedetector. In order to investigate the time resolution, a Time-Of-Flight(TOF) between a trigger detector andthe monitor detector was measured. As the trigger detector, 1-mm-thick plastic scintillator of which bothends were connected on photomultiplier tubes was used. Two parallel plate avalanche counters (PPAC)

10

Trigger detector
Monitor detector
SB2 Beam-window
Al 0.1 mm

84

Kr beamPPAC

NaI detector

Fig. 2. Schematic layout of the monitor detector

were used to measure the position distribution of the beam and to obtain the beam profile at the carbon
foil by a ray-trace technique.
In this measurement, the potentials were set as Vfoil = −3250 V, Vacc = Vin = −2500 V, and Vout =−4000 V so as to the TOF spectrum was narrow. A typical TOF spectrum is shown in Fig. 3. The time
resolution is obtained by fitting the TOF spectrum with a Gaussian function. The obtained width of thepeak includes the intrinsic time resolution of the trigger detector, which is σ = 50 ps. By subtracting thecontribution of the trigger detector, preliminary intrinsic time resolution was deduced as σ ≈ 130 ps. The
obtained detection efficiency is about 70%.
1800

Counts [ /12.5 ps]

1600
1400
1200
1000
800
600
400
200
0
-2

-1.5

-1

-0.5

0

0.5

TOF [ns]Fig. 3. TOF spectrum

References[1] Y. Yano., Nucl. Instr. and Meth., B261, 1009(2007).
[2] Y. Yamaguchi et al., Nucl. Instr. and Meth., B266, 4575(2008).
[3] M. Kanazawa, et. al., Nucl. Phys., A 74, (2004) 393.

11

1

1.5

2

2.4

Test of rotating magnetic field system for β -NMR method

D. Nagae, Y. Ishibashi, N. Inaba, S. Okada, K. Sawahata, Y. Abe and A. Ozawa
A rotating magnetic field system has been developing [1, 2] to determine a sign of magnetic (µ )moment by the β -ray detected nuclear magnetic resonance (β -NMR) method [3]. Using the rotating
magnetic field system, a measurement of the sign of the µ moment for proton has been conducted by aπ /2 pulse NMR method and successfully confirmed the sign of the µ moment for proton [4].
In the present work a performance of the system was studied with spin-polarized 20 F (I = 2+ , T1/2 =11.163 s, µ (20 F) = +2.09335(9) µN ) nuclei at the Research Center for Nuclear Physics, Osaka University.
A spin-polarized 20 F was produced via nuclear-polarization transfer reaction with spin-polarized deuteronbeam at E = 10 MeV on a 0.5-mm-thickness CaF2 crystal. The CaF2 crystal was mounted at a center ofthe β -NMR apparatus (see Fig. 1 (a)). A static magnetic field B0 = 290 mT was applied to the crystal.
The β rays emitted from 20 F nuclei were detected with scintillator telescopes located above and below
the crystal. The up/down ratio R of the β -ray counts is written as R0 = a(1 + v/c · Aβ P)/(1 − v/c · Aβ P),
where a denotes a constant factor representing asymmetries in counter solid angles and efficiencies, v
and c are the velocity of the β particle and light. Aβ and P denote the β -ray asymmetry factor and spinpolarization. A rotating magnetic field perpendicular to the static field is applied to 20 F by using the twopairs of coils. If the frequency and the direction of the rotating magnetic field corresponds to the resonanceone, the direction of the spin polarization is changed from P to −P by the NMR. Thus the up/down ratio
is changed as R = a(1 − v/c · Aβ P)/(1 + v/c · Aβ P). When the polarization is altered due to the resonant
spin change, a change appears in a ratio R0 /R. The β -ray asymmetry Aβ P is obtained as,√
Aβ P = √(R0 /R) − 1(R0 /R) + 1,(1)

here, we took an approximation that v/c ≃ 1, since only a high-energy portion of the β particle wasincluded in the analysis. The deuteron beam was pulsed with beam-on and -off periods of 16 and 22.02 s,
respectively. In the beam-off period of a beam cycle, the RF magnetic field B1 was applied for the first
10 ms duration. Then, the β rays were counted for 22 s, and in the last 10 ms of the beam-off period theB1 field was applied again to restore the spin direction. At first we measured the R0 without B1 field andthen measured the R with the B1 field. This cycle were repeated until the sufficient measurement statistics
were attained.
Figure 2 shows the measured Aβ P values for 20 F with the linear B1 field 1, and 2, ,a right-circularly
rotating B1 field, and a left-circularly rotating B1 field. A definition of the RF magnetic field is shownin Fig. 1 (b). The linear B1 fields can be regarded as superpositions of right- and left-circularly rotating
magnetic fields. Thus, the spin reversal is occurred when the frequency of the B1 field is correspond to theresonant one. The frequency of these B1 fields were swept from 2047.5 kHz to 2152.5 kHz during 10 ms.
The Aβ P values of the linear B1 fields are indicated the occurrence of the spin reversal. Considering theobtained Aβ P values, the asymmetry parameter of 20 F (Aβ = −1/3), and the direction of B0 (from up todown), the direction of the spin-polarization of 20 F was been determined as parallel to the B0 . The Aβ P

12

(b)
Magnet pole
Static Magnetic field (B0)

RF coils
Spin-polarized
deuteron beam

Right
Spin-polarized
deuteron beam

CaF2 crystal

β-ray counter
telescopes

Spin direction of 20F

B0

Left
Linear B1 field 1(a)Linear B1 field 2

Fig. 1. (a) Schematic layout of the β -NMR apparatus, (b) Definition of RF magnetic fields

value with the left-circularly rotating B1 field is clearly deviated from 0, while the value with the rightcircularly rotating B1 field is small. These results indicate that the sign of the µ (20 F) moment is positive.
The obtained sign derived from this analysis is in agreement with the reported one [5].
In the present work, spin polarizations P of 41 Sc were measured. The spin-polarized 41 Sc was pro⃗ 41 Sc⃗ at E ⃗ = 20 MeV. For the reaction target, two CaO pellets made from CaO powder,
duced in a 40 Ca(d,n)
dand from a CaCO3 powder were used. The obtained Ps and previous result [6] are shown in Fig. 3. In
the previous measurement, a CaO pellet made from CaO powder was used and the energy of the spinpolarized deuteron beam was set at Ed⃗ = 7 MeV. While the polarizations of present work were maintained
both CaO pellets, the values were extremely small compared with the previous value. These result suggest
the spin-polarization is well transferred in a low energy reaction.
0.4

3.5
3.0
2.5

0.2

P [%]

AβP [%]

0.3

0.1

2.0
1.5
1.0

0.0

0.5
-0.1
Linear RF Linear RF Right
field 1
field 2-circularly

0.0

Left
-circularly

Previous work

CaCO3

CaO

Fig. 3. Spin polarizations of 41 Sc

Fig. 2. Obtained Aβ P value of 20 F

References[1] T. Niwa et al., UTTAC annual report 2011, UTTAC-81, 5 (2012).
[2] D. Nagae et al., Hype. Int., 220, 65 (2013).
[3] K. Sugimoto et al., J. Phys. Soc. Jpn. 21, 213 (1966).
[4] D. Nagae et al., UTTAC annual report 2012, UTTAC-82, 7 (2013).
[5] N.J. Stone, Atomic Data and Nuclear Data Tables 90, 75 (2005).
[6] Y. Ishibashi et al., UTTAC annual report 2010, UTTAC-80, 17 (2011).

13

3.
MATERIALS SCIENCE

3.1 Effect of synthesis conditions on magnetic properties of ferromagnetic
iron oxide nanoparticles using Mössbauer spectroscopy
Akari Horiuchi, M. Kishimoto, H. Yanagihara and E. Kita
Modification of the physical properties of nanoparticles is greatly affected by shape, and thus
controlling nanoparticle shape is an important issue. Shape especially influences the magnetic anisotropy.
We have developed oval-shaped nano-platelets composed of ferromagnetic iron oxides smaller than 50 nm
in size. The effect of reaction temperature on magnetic properties during dehydration is reported.
Ferromagnetic iron oxide nanoparticles were prepared as follows: first, α-FeOOH nano-platelets,
used as precursor materials, were synthesized through precipitation and a hydrothermal treatment.
Tetra-ethylene glycol (TEG) was used as a polyhydric alcohol for reducing the α-FeOOH nano-platelets. A
dispersion of α-FeOOH nanoparticles and TEG was heated to several predetermined temperatures. Welabeled the various nanoparticle samples as GTe260 through GTe300, corresponding to reaction
temperatures between 260 and 300 °C. Magnetizations of dry powdered samples were measured using avibration sample magnetometer (VSM). Crystal structures of the samples were obtained using X-ray
diffraction (XRD). Mössbauer spectra for GTe290 were recorded at 4.2 K, 77 K, and room temperature.
These spectra were numerically analyzed using fitting software (MössWinn 4.0).
Figure 1 shows the XRD patterns of samples obtained by heating α-FeOOH to various
temperatures in the 260–300 °C range. Diffraction peak intensity corresponding to the spinel structure
increased with increased reaction temperature. However, the peak originating from α-Fe2O3 became very
faint in XRD patterns of GTe300.
Figure 2 shows the Mössbauer spectra of GTe290 recorded at 4.2 K, 77 K, and 295 K. The solidlines indicate the fitted results, which are summarized in Table 2. Three ferromagnetic sextets and adoublet with negligible area ratio (5.8%) reasonably fit the spectrum recorded at 295 K. The sub-spectrumwith the highest hyperfine field (Hhf) value, 506 kOe, was attributed to the Fe3+ ions corresponding to
α-Fe2O3. The sub-spectra with the second largest, 489 kOe, and smallest, 454 kOe, Hhf values wereassigned to the Fe3+ ion in the A lattice and the Fe2.5+ ion in the B lattice of Fe3O4, respectively.
Although GTe290 was characterized as a mixture of Fe3O4 and α-Fe2O3 nanoparticles, there
remained a possibility that γ-Fe2O3 particles were partially mixed in as well. In order to confirm that
GTe290 was a mixture of only Fe3O4 and α-Fe2O3, measurement was carried out at low temperature. Threeferromagnetic sextets fit the spectrum recorded at 4.2 K. The sub-spectrum with the highest Hhf, about 532
kOe, was attributed to the Fe3+ ions corresponding to α-Fe2O3. Those with the second largest, 510 kOe,
and smallest, 467 kOe, Hhf were respectively assigned to the Fe3+ ion in the B lattice and the Fe2+ ion in
the B lattice of Fe3O4, an inverse spinel structure with a cubic cell. Therefore, spinel-structured iron oxide
obtained by heating α-FeOOH particle dispersions in TEG was identified as Fe3O4.
Table 1 shows the variation of the coercive force, saturation magnetization, and squarenessagainst the reaction temperature. The coercive force remained nearly constant at 133–153 Oe irrespectiveof the reaction temperature. However, the saturation magnetization of the samples increased from 6.87 to15

81.4 emu·g−1 as the reaction temperature increased.
Table 1. Magnetic properties of samples synthesized
Intensity [arb.units]

Hematite
Spinel
300 ℃
290 ℃
280 ℃
270 ℃
260 ℃

20

30

40

2θ [°]

50

60

at different temperatures.
T
Ms
Hc
sampleS[℃] [emu·g−1] [Oe]6.87
145 0.26
GTe260 260
17.1
133 0.22
GTe270 270
28.8
146 0.23
GTe280 280
54.1
153 0.26
GTe290 290
81.4
150 0.33
GTe300 300

Figure 1. X-ray diffraction patterns of samples
synthesized at different temperatures.

Counts [arb. units]

295K

77 K
Figure 2. Mössbauer spectra of a sample
synthesized at 290 °C.

4.2 K

-12

-8

295

77
4.2

-4

0

4

Velocity [mm/s]

F1
F2
F3
D

8

12

Table 2. Mössbauer fitting parameters.
IS
QS
Hhf
Area
Ion
−1
[kOe] [mm·s ] [mm·s−1] ratio [%]
506
0.361
-0.174
21.8
Fe3+
489
0.349
-0.093
38.3
Fe3+(A)
454
0.621
0.027
34.2
Fe2.5+(B)
0.504
2.052
5.80
528
0.472
-0.187
43.7
Fe3+
476
0.756
-0.14320.7
Fe2+(B)507
0.415-0.037
35.6
532
0.485
-0.174
45.5
Fe3+
510
0.438
-0.046
43.5
Fe3+(B)467
0.936-0.291
11.0
Fe2+(B)

16

Crystalstructure
α-Fe2O3Fe3O4Fe3O4α-Fe2O3
α-Fe2O3
Fe3O4
Fe3O4

3.2

Conversion electron Mössbauer spectroscopy (CEMS) of cobalt ferrite
thin films grown by sputtering using a 57Fe enriched target

R. Aoyama, H. Yanagihara, Ko Mibu and E. Kita
High perpendicular magnetic anisotropy (PMA) materials have attracted attention because of theirpotential use in magnetic recording media and other practical applications. In addition to high PMA,
materials that do not contain Pt, a rare metal, are ideal for the future uses to avoid resource issues such as
scarcity. The magnetization and PMA of cobalt ferrite thin films, which are high PMA materials, changewith composition and production conditions. As such, cobalt ferrite thin films are the subject of our study,
and we have reported changes in their magnetization and PMA by changing their composition andproduction conditions [1].
In order to clarify the mechanism of anisotropy in cobalt ferrite thin films, the electronic andmagnetic states should be studied using Mössbauer spectroscopy. However, it is not possible to detect
these electronic and magnetic states via transmission through the sample in thin films grown on thicksubstrates. Conversion electron Mössbauer spectroscopy (CEMS) can be used on such samples because
the electrons emitted back from the surface are detected. However, it takes a long time to gather CEMS
results from samples thinner than 100 nm because of the insufficient amount of 57Fe nuclei in cobalt ferrite
thin films. 57Fe enrichment is a well-known technique to decrease measurement time, but 57Fe enriched RF
sputtering targets are expensive to produce. To solve this problem, we prepared a locally enriched 57Fe
target.
Figure 1 shows the schematic illustration of the locally 57Fe enriched target system. The system wascomposed of a 1 mm thick doughnut shaped 57Fe enriched disk, covering the erosion part of sputtering,
and a natural Fe base plate. Cost was reduced by shrinking the area of the enriched disk and lowering thequantity of 57Fe used to 25% of the disk material. Cobalt ferrite thin films for CEMS were grown on a
MgO(001) single crystal substrate by co-sputtering using a locally enriched 57Fe target and Co target. The
O2 flow rate was set to 7 sccm and the substrate temperature was fixed at 300 ºC during sputtering.

Figure 1. Schematic of a locally enriched 57Fe target for RF sputtering.
Figure 2 shows a CEMS spectrum for a Co0.65Fe2.35O4 thin film. The time to collect data ofequivalent quality was ideally shortened by a factor of ten because the amount of 57Fe was 25% in the17enriched target compared to 2.3% in natural Fe. Data collected for 16 hours is shown in Figure 2, and thespectrum has a distinct enough signal to noise ratio for detailed discussion. The enriched 57Fe combination
target enabled us to shorten measuring time drastically and will be a powerful tool in analyzing themagnetic state of Fe based thin films.
The spectrum was fit to a combination of three ferromagnetic sub-spectra, and the fitting parameters,
hyperfine field (H ), isomer shift (IS) and quadrupole split (Q.S.) are listed in Table I. The spectrum washf

fairly symmetric and the isomer shifts were 0.3–0.4 mm/s and were fairly similar to those of trivalent Fe
ions. It was supposed that about 15% (= 0.35/2.35) of Fe atoms should be in the divalent state, however, it
is not clearly seen in the spectrum. This suggested that the film was well oxidized and the number ofdivalent Fe atoms was small. Sites with small hyperfine fields (site 1) may be attributed to the surface Fe
atoms.

Figure 2. Conversion electron Mössbauer spectroscopy (CEMS) spectrum for a
Co0.65Fe2.35O4 thin film recorded at 300 K. Solid lines indicate fitted results.
Table I. Mössbauer fitting parameters for a Co0.65Fe2.35O4 thin film
1
1
Sub-spectrum Hhf (kOe) IS (mm·s− ) Q.S. (mm·s− ) Area (%)
Ion (site)
3+

F1

426.0

0.307

0.020

23.51

Fe (?)

F2

458.5

0.305

0.024

54.60

Fe (B)

F3

482.8

0.365

-0.01921.89

Fe (A)

3+

3+

References[1] T. Niizeki, Y. Utsumi, R. Aoyama, H. Yanagihara, J. Inoue, Y. Yamasaki, H. Nakao, K. Koike, and Eiji
Kita, Appl. Phys. Lett., 103, 162407 (2013). 104, 059902 (2014) [erratum].

18

3.3

Magnetic states of ion implanted Fe3O4 thin films studied by Mössbauer
spectroscopy

Eiji Kita, K.Z. Suzuki, Yang Liu, Y. Utsumi, J. Morishita. T. Niizeki, K. Mibu and H. Yanagihara
Oxide ferro-/ferrimagnetic materials have been investigated for many years and have tremendous
potential for use in various applications such as high-density recording media and spintronic devices.
Recently, we fabricated spinel-type oxide thin films using RF sputtering and found strong perpendicularmagnetic anisotropy energy on the order of 10 Mergs/cm3 in Co ferrite thin films grown on MgO(001)substrates [1]. These materials have potential as magnetic recording media, and one practical application is
the use of nanoscale patterning in high-density recording media. Bit-patterned media (BPM) have emerged
as the dominant candidate for developing ultra-high density hard disk systems [2]. Recently, as the firststep toward pattern formation of spinel type ferromagnetic oxides, we investigated theeffectiveness of controlling the magnetism of a typical spinel ferromagnetic oxide, Fe3O4, via N2
and Kr ion implantation [3,4]. Mössbauer study on the effect of Kr irradiation on Fe3O4 thin films isreported.
Ferrite thin films were prepared using reactive sputtering, introducing O2 gas into Ar base gas
during film growth in an RF planner magnetron sputtering apparatus [5]. An Ar gas flow of 30 sccm wasintroduced, and the O2 flow was controlled at 0.5 sccm. Cleaved MgO(001) single crystals were used as
substrates. Sputter deposition was performed at the substrate temperature of 300 °C and 13-nm-thick thinfilms were obtained for magnetization measurements. For Mössbauer studies, thin films with a thicknessof 13 nm were fabricated in the same manner as other samples by using the 57Fe enriched Fe3O4 target
system [6]. The Fe3O4 films were covered with a carbon layer of around 10 nm prior to ion irradiation. Kr
ions were accelerated by a conventional ion implantation system. The acceleration voltages (Vacc) was set
to 30 kV, and the dosages of ions were controlled from 1 × 1014 to 6 × 1015 ions/cm2. The Mössbauer study
was carried out using standard conversion electron Mössbauer spectroscopy.

Fig. 1. Dependence of saturation magnetization,
Ms, on Kr ion implantation, for three Fe3O4
sputtered thin films. Solid circles and open circles
show the magnetization for the samples with C
coated and without C coated layer, respectively.
Closed squares show the magnetization of thesample with C coated layer irradiated by N2 ions.

19Fig. 2. CEMS spectra recorded at 300 K.

The Mössbauer spectra of the Fe3O4 thin films with Kr-irradiation treatments of (b) 2 × 1015
ions/cm2 and (c) 4 × 1015 are in Fig. 2. Magnetization levels of 200 and 0 emu/cm3 were achieved forsamples (b) and (c), respectively. The spectrum of the low-irradiation sample in (b) was fitted to the
combination of a weak broad magnetic sextet, a non-magnetic doublet, and a non-magnetic singlet. The
spectrum for a 50 nm thick Fe3O4 film without irradiation is plotted as a reference in Fig. 2 (a) and was
fitted to the combination of two magnetic subspectra with bulk parameters. The ferromagnetic component
has a hyperfine field of 445 kOe and an isomer shift of 0.50 mm/s which are almost comparable to thoseof Fe3+ ions and wide line widths. The area ratio of a ferromagnetic component is roughly estimated to be
23%, and this agrees qualitatively with the value of saturation magnetization.
A further increase in irradiation ions resulted in the disappearance of the ferromagnetic componentof (b), and the paramagnetic components can be fitted by using the same parameters as those for sample(b). There are no intermediate subspectra with smaller hyperfine fields than those shown in the spectra of(b). Our results imply two-phase separation and absence of any intermediate phase in the irradiated sample,
thereby suggesting that the transition of Fe3O4 from ferromagnetic to paramagnetic phases occurred
sharply due to Kr ion irradiation.
References[1] T. Niizeki, et al.,, Appl. Phys. Lett., 103, 162407 (2013). 104, 059902 (2014) [erratum].
[2] B. D. Terris and T. Thomson, J. Phys. D: Appl. Phys., 38, R199 (2005).
[3] Eiji Kita, et al., Jpn. J. Appl. Phys. 53 (2014) 020306.
[4] Eiji Kita, et al., J. Appl. Phys., 115 (2014) 17B907.
[5] H. Yanagihara, et al., J. Phys. D: Appl. Phys. 46, 175004 (2013). 47, 129501 (2014) [erratum].
[6] R. Aoyama, H. Yanagihara, K. Mibu and E. Kita, UTTAC Annual report 2013.

20

3.4

Mössbauer study of CoxFe4−xN films grown by molecular beam epitaxy

K. Ito, T. Sanai, Y. Yasutomi, E. Kita and T. Suemasu
CoxFe4−xN are promising ferromagnetic materials forapplication to spintronics devices due to their large
spin-polarization of density of states at the Fermi level

I site(PD) [1-3]. Co3FeN is expected to have larger |PD| of 0.75

IIA site(PD < 0) than that of Fe4N when Fe atoms are located at

IIB sitethe corner (I) sites, and Co atoms at the face-centered (II)Nsites in the anti-perovskite unit cell (Fig. 1). X-ray
magnetic circular dichroism (XMCD) measurements
were performed on the epitaxial Co3FeN film, andFig. 1 Lattice structure of anti-perovskite nitride.

deduced spin magnetic moments of Fe and Co atoms in the Co3FeN film were very close to those reported
in Fe4N and Co4N, respectively [4]. It was suggested that Fe and Co atoms in the Co3FeN film werelocated at both I and II sites. In this study, we evaluated the atomic sites of Fe atoms in epitaxial Fe4N,
CoFe3N, and Co3FeN films using conversion electron Mössbauer Spectroscopy (CEMS).
We performed CEMS measurements at room temperature for 19-nm-thick Fe4N (sample A),
25-nm-thick CoFe3N (sample B), and 74-nm-thick Co3FeN (sample C) films grown on SrTiO3(001)substrates by molecular beam epitaxy, supplying 57Fe enriched (20%) solid iron and radio-frequency
nitrogen plasma, simultaneously at 450 ºC. The velocity and isomer shift were calibrated using a standard
spectrum of α-Fe. Obtained Mössbauer spectra were analyzed using commercially available fitting
software, MössWinn 4.0.
Figures 2(a)-2(c) show the CEMS spectra for samples A-C, respectively. Obtained CEMS spectra were
decomposed into three ferromagnetic components and one nonmagnetic component. We consider that thenonmagnetic component is attributed to the surface oxidized layer. The values of a hyperﬁne ﬁeld, an
isomer shift, and a quadrupole splitting of sample A were in good agreement with those reported [5].
However, the relative area ratio of I : II sites was not an ideal value of 1 : 3, but 0.53 : 3. The in-planelattice parameter of the Fe4N layer in sample A deduced from x-ray diffraction measurements was 0.3812
nm and is almost the same as that of the bulk value (0.3795 nm) [5]. Thus, we believe that thisextremely-small occupation value for I sites is not attributed to Fe vacancies, but to the excess insertion
and/or site-disorder of the N atoms since I sites are equivalent to II sites when the N atoms are located atinterstitial sites between the two nearest I sites. The results of CEMS measurements for samples B and C
also indicated that Fe atoms in samples B and C are located at both I and II sites and/or there is thesite-disorder of the N atoms. This is consistent with our previous report [4]. This trend is also theoreticallysupported by the first-principles calculation, which shows that Co atoms tend to occupy both the I and II
sites in CoxFe4-xN from the view point of total energy [6]. In order to obtain highly spin-polarized
CoxFe4-xN, optimization of the growth conditions is required to prevent the site-disorders.

21

-10 -8

-6

Data
Total
I
IIA
IIB
Doublet

-4

-2

0

2

4

6

8

(b)
sample B

Intensity [arb. unit]

Intensity [arb. unit](a)sample A

10-10 -8Intensity [arb. unit]

Velocity [mm/s]

-6

-4

-2

0

2

4

6

8

10

Velocity [mm/s](c)sample C

Fig. 2 Mössbauer spectra of (a) Fe4N, (b) CoFe3N,-10 -8

-6

-4

-2

0

2

4

6

8

and (c) Co3FeN films.

10Velocity [mm/s]
References[1] S. Kokado, N. Fujima, K. Harigaya, H. Shimizu, and A. Sakuma, Phys. Rev. B 73, 172410 (2006).
[2] Y. Imai, Y. Takahashi, and T. Kumagai, J. Magn. Magn. Mater. 322, 2665 (2010).
[3] Y. Takahashi, Y. Imai, and T. Kumagai, J. Magn. Magn. Mater. 323, 2941 (2011).
[4] K. Ito, T. Sanai, S. Zhu, Y. Yasutomi, K. Toko, S. Honda, S. Ueda, Y. Takeda, Y. Saitoh, Y. Imai, A.
Kimura, and T. Suemasu, Appl. Phys. Lett. 103, 232403 (2013).
[5] J. C. Wood and A. J. Nozik, Phys. Rev. B 4, 2224 (1971).
[6] P. Monachesi, T. Björkman, T. Gasche, and O. Eriksson, Phys. Rev. B 88, 054420 (2013).

22

3.5

Cluster effect on the yield of secondary electrons produced by innershell electron excitation

S. Tomita, Y. Shiina, S. Tamura, R. Kinoshita, S. Ishii and K. Sasa
The generation rate of scattered electrons is generally assumed to be proportional to the inelastic
stopping power because of the observed proportionality between the secondary electron yield and thestopping power [1]. However, it is experimentally shown that the proportionality does not hold for thecase of fast carbon cluster ions. The secondary-electron yield for 0.5 MeV/atom C+
4 ions is approximately
50% of that of atomic ions with the same velocity [2], whereas the electronic stopping power of C+
4 isapproximately the same as that of four atomic ions [3]. There must be a specific mechanism that reduces
the secondary-electron yield despite of the same energy deposit. To investigate this problem further, wemeasured the molecular effect on the yield of secondary electrons which stem from close collisions in a
first-excitation process.
The experiments were conducted at Tandem Accelerator Complex at the University of Tsukuba (UTTAC). A schematic of the experimental apparatus is shown in Fig.1. The accelerated molecular ions
impinged on a thin carbon foil after passing through an aperture of 1 mm in diameter. The carbon foil
was set with an angle of 45◦ with respect to the direction of fast ion beams. The foil was purchased from
Arizona Carbon Foil Co., whose nominal thickness was 5 µg/cm2 . The ions that penetrated through thecarbon foil were detected by an ion-implanted-silicon charged particle detector (ORTEC ULTRA). The
opening angle of the detector was 1.6◦ , which was limited by a tiny aperture placed in front of the detector.
The individual atoms scattered more than 1.6◦ by close collision with a target atom were not detected by
the detector. The secondary electrons produced in backwards by a fast-molecule impact were extracted
towards a micro channel plate (MCP) detector. The MCP signal was amplified with a charge-sensitive
preamplifier and recorded with an ADC coincident with a signal from SSD event by event, using CAMAC
data acquisition.
The coincident measurement with the projectile atoms allows us to measure backward secondaryelectron yields as a function of the number of detected atoms. The mean values of secondary-electron()

yields are shown in Fig. 2 together with the results of single carbon atom impacts, γi C+ (i = 0, 1).

Secondary

MCP

0.5 MeV/atomSSDelectrons

Grid

Cn+

Carbon foil
φ1.0

φ3.0

aparture

aparture050

100 (mm)Fig. 1. Schematic drawing of experimental apparatus.

23

245

365

240

360

235

355

+

i

2

(C )

+

(C )

-5

i

(arb. unit)

0

-10
230

350

-15
0

1

2

345

Number of detected atoms i

( +)
( +)
+
Fig. 2. Secondary electron yields for C+, (crosses) as a function
2 , γi C2 , (open circles) and C , γi Cof the number of detected projectile atoms i. ∆γ shows the difference in secondary electron yields
from that of the case that no constituent projectile atom was detected by the silicon detector.

The yields for both cases are plotted together to show the difference from the case that no projectile atoms
were detected by silicon detector; therefore, the total yield of secondary electrons is shown on a different
axis. It is clear that the secondary-electron yield decreases with the number of detected atoms. This canbe reasonably understood as a contribution of inner shell electron excitation, similar to the case reported
by Ogawa et. al. [4] for proton impacts. The classical trajectory calculation with Moliére potential
results a closest distance of 0.02 Åfor a scattering angle of 1.6◦ , which is much smaller than the radius of
0.092 Åwhere the K-shell electron density of a carbon atom has its maximum value [5].
Note that there seems to be no molecular effect on the contribution of inner shell electron excitation,
whereas total secondary electron yields are strongly suppressed. These results can be generally describedas that there is no molecular effect in the phenomena involving violent collisions, such as inner-shell electron excitation in the present case. The enhancement for inner shell excitation stems from single-electron
excitation, i.e., it excludes collective excitation such as plasmon excitations. However, it is difficult toconclude that the cluster effect occurs in a collective excitation.

References[1] H. Rothard, K. Kroneberger, A. Clouvas, E. Veje, P. Lorenzen, N. Keller, J. U. Kemmler, W. Meckbach, and K.-O. Groeneveld. Physical Review A, 41:2521, 1990.
[2] S. Tomita, S. Yoda, R. Uchiyama, S. Ishii, K. Sasa, T. Kaneko, and H. Kudo. Physical Review A(Atomic, Molecular, and Optical Physics), 73:060901, 2006.
[3] S. Tomita, M. Murakami, N. Sakamoto, S. Ishii, K. Sasa, T. Kaneko, and H. Kudo. Physical Review
A, 82:044901, 2010.
[4] H. Ogawa, H. Tsuchida, and N. Sakamoto. Physical Review A, 68:052901, 2003.
[5] J. P. Desclaux. Atomic Data and Nuclear Data Tables, 12:311, 1973.

24

3.6

Limit of detection for hydrogen by developed high-resolusion ERDA
system

D. Sekiba 1, K. Chito1, I. Harayama1, Y. Watahiki1, S. Ishii1 and K. Ozeki2
Recently we have developed high-resolution ERDA system on the D-course of the 1 MV Tandetron
accelerator in UTTAC (University of Tsukuba, Tandem Accelerator Complex). The system is optimized todetect the hydrogen in the surface and subsurface of solids, taking into account the design of K. Kimura etal. of Kyoto University [1]. The analyzer consists of 90 degree sector lens and PSD (position sensitive
detector) with MCP (micro channel plate made by Hamamatsu Photonics K.K.). While high-resolution
ERDA with the sector lens demonstrates the nice depth resolution (~ 0.28 nm for the Si substrate), thedetection limit for hydrogen is not good enough compared to that of SIMS (Secondary Ion Mass
Spectroscopy) ~ 1018 particle/cm3. The detection limit of analysis is generally determined by an intrinsic
background produced by the detection system itself. In the case of ion beam analysis with sector lens and
PSD, the origins of the background are mainly dark current of MCP and stray particles. Hashimoto et al.
recently tried the system, which distinguishes the dark current and/or real signals, taking the coincidenceof ion detection and secondary electron detection by means of two MCP [2,3]. There 200 ppm for As in
the Si substrate with the data acquisition time of 1000 s for RBS (Rutherford Backscattering
Spectroscopy) and 0.08 at.% B in the Si substrate for ERDA were achieved. On the other hand, thedetailed detection limit of high-resolution ERDA for hydrogen has never been reported. We show theresult of detection limit analysis for hydrogen with high-resolution ERDA employing a-C:H(hydrogenized amorphous carbon) film.
The 500 keV 16O+ beam was shaped to 1 mm square with a four-quadrant slit and was irradiated onto
the sample. The typical beam current was the several tens nA. The recoil angle was set at 30 degree fromthe beam incident direction. The dimension of the detection system is the same reported in Ref [2]. A thin
Mylar foil (0.5 µm thickness) was put in front of the MCP to remove the forward scattered incident
particles (16O). The coincidence system reported in Ref. [2,3] was not used in the present study. The
sample, a-C:H film (~150 nm thickness) deposited on Si(100) by chemical vapor desorption, was preparedby K. Ozeki in Ibaraki University. The contained hydrogen amount was carefully determined by means ofconventional ERDA with the condition previously reported [4]. As a result, the composition ratio ofhydrogen and heavy hydrogen in a-C:H were estimated as H : D : C = 33.1 : 11.5 : 55.4. By using SRIM
code, the concentration of hydrogen in the sample was determined as 7.05 x 1022 particles/cm3.
Figure 1(left) shows the high-resolution ERDA spectra taken on the above described sample. The
surface peak is observed at ~ 500 ch indicating the adsorbed water on the surface. The edges at ~ 150 ch
and 830 ch are artifacts due to the edges of MCP. To determine the limit of detection of hydrogen from Fig.
1, the counts of signal and background were integrated in the regions of 300 ch ~ 400 ch and 500 ch ~ 600

1

UTTAC, Univ. of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577, Japan
Department of Mechanical Engineering, Ibaraki Univ. Nakanarusawa 4-12-1, Hitachi, Ibaraki 316-8511, Japan225

ch. According to the simple definition suggested by Hashimoto et al. [2,3], the limit of detection forhydrogen with this system was estimated as 1.6 x 1020 particles/cm3 with the data acquisition time of 308 s.
The beam irradiation necessary for this measurement was 2.2 µC.

Figure1: (left) The high-resolution ERDA spectrum taken on a-C:H film with the 500 keV 16O+ beam. The
sample surface corresponds to ~ 500 ch, while the edges at ~ 150 ch and ~ 830 ch indicate the edges of
MCP. (right) The change of the spectrum feature of high-resolution ERDA on a-C:H due to the damage.
The spectra were taken with every ~2.2 µC.
Interestingly the contribution of stray particles, in this case mainly hydrogen scattered by inner wall of
the chamber, was observed in Fig. 1(right). The spectra in Fig. 1(right) were taken with every ~ 2.2 µC on
the same position of the sample. The intensity corresponding to the hydrogen concentration was
continuously decreases indicating the desorption of hydrogen due to the beam irradiation damage.
Accompanying the decrease of the signal intensity in the subsurface region, the intensity of backgroundseen in the vacuum region also is suppressed. This implies that the stray hydrogen ions, which recoilsfrom the subsurface and bulk, are not negligible compared to the dark current of MCP, when the sample isthick enough and contains a lot of hydrogen. In fact, in the case of thin oxide film (~ 4 nm) on SiC whichcontains much less hydrogen in bulk, we obtained a better limit of detection for hydrogen ~ 2.8 x 1019
particles/cm3.
As a future work the development of a system, which can distinguish not only the dark current of MCP
but also the stray recoil particle, will be necessary to take the further improvement of limit of detection in
high-resolution ERDA.

References[1] K. Kimura, K. Nakajima, H. Imura, Nucl. Instr. and Meth. B 140 (1998) 397-401.
[2] H. Hashimoto, K. Nakajima, K. Sasakawa, K. Kimura, Rev. Sci. Instrum. 82 (2011) 063301.
[3] H. Hashimoto, S. Fujita, K. Nakajima, M. Suzuki, K. Sasakawa, K. Kimura, Nucl. Instr. and Meth. B
273 (2012) 241-244.
[4] D. Sekiba, M. Horikoshi, S. Abe, S. Ishii, J. Appl. Phys., 106 (2009) 114912-1-5.

26

4.
ACCELERATOR MASS SPECTROMETRY

4.1

Depth profiles of 129I and 129I / 127I ratio in soil at the near-field site of
the Fukushima Dai-ichi Nuclear Power Plant

T. Matsunaka, K. Sasa, K. Sueki, T. Takahashi, M. Matsumura, Y. Satou, N. Shibayama, J. Kitagawa 1, N.
Kinoshita 2, and H. Matsuzaki 3
Massive nuclear fission products such as radioiodine were deposited on the surface in Fukushima via
radioactive plume derived from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. In orderto evaluate inventory and penetration of accident-derived 129I in the highly-contaminated area, depth
profiles of 129I concentration and 129I / 127I ratio in 5-cm-long soil cores after the accident were investigatedat three sites shown in Fig.1: NM-6 site at Namie town (7.5 km northwest site from the FDNPP), Iw-2 site
at Okuma town (4.3 km west site from the FDNPP) and Iw-8 site at Okuma town (8.2 km west site fromthe FDNPP).

Fig.1. Sampling sites of 5-cm-long soil core within 10 km from the FDNPP on the
distribution map of radiation dose as of November 5, 2011 (4th) mapping by
MEXT.
Total 129I inventories in the soil cores were estimated to be 1.80 Bq m−2 at NM-6, 1.84 Bq m−2 at Iw-2
and 0.68 Bq m−2 at Iw-8. Average 129I / 127I ratio in each soil cores after the accident (NM-6: 8.6 × 10−7,
Iw-2: 2.1 × 10−6, Iw-8: 4.2 × 10−7) shows typical ratios of the contaminated surface soils in Fukushima(1.5 × 10−8 – 7.2 × 10−6) [1]. Therefore, accident-derived 129I deposited at NM-6 and Iw-2 were 2.7 times
higher than that at Iw-8. Depth profiles of 129I concentration and 129I / 127I ratio exponentially declined withdepth (Fig.2). Approximately 90% of deposited 129I in 5-cm-long soil cores were observed in the surface
1

Radiation Science Center, High Energy Accelerator Research Organization
Institute of Technology, Shimizu Corporation
3
MALT, The University of Tokyo2

27

layer of 16.1 – 17.8 kg m−2 (1.6 – 2.5 cm) in depth. In addition, the relaxation mass depths (h0) of 129I were
determined to be 8.2 kg m−2 at NM-6, 9.5 kg m−2 at Iw-2 and 9.2 kg m−2 at Iw-8.

A)

Cumulative

Math depth (kg m-2)

0

0

0.5

1

1.5

0

0

-2

I inventory (Bq m )

0.5

1

1.5

2

0

10

10

10

20

20

20

30

30

30

40

Total

40

129

I inventory

Total

-2

50

NM-6

I inventory

0.5

1

Total

= 1.84 Bq m

60

Iw-2

1.5

2

129

I inventory
-2

50

129

B)

0

40

129

-2

50

= 1.80 Bq m

60

= 0.68 Bq m

Iw-8

60

-1

I concentration (mBq kg )

0

0

50

C(0) = 150 mBq kg

10Math depth (kg m-2)

2

129

-1

100

150

-2

h = 8.2 kg m

0
10

0

0

50

100

C(0) = 193 mBq kg

150

-1

-2

h = 9.5 kg m

0
10

50

100

150

C(0) = 71.1 mBq kg-1-2

h = 9.2 kg m
0

0

20

20

20

30

30

30

40

40

40

50

50

50

60

NM-6 60

Iw-2

0

60

Iw-8

Fig.2. Cumulative 129I inventories (A) and depth profiles of 129I concentrations (B) in 5-cm-long soilcore from NM-6, Iw-2 and Iw-8. Total 129I inventories in the core, estimated activity 129I
concentration of surface soil (C(0)) and relaxation mass depth (h0) of 129I are shown in the
profiles.

References[1] Miyake et al. (2012) Geochemical Journal, 46, 327-333.

28

4.2

Study on monitoring of volcanic activity using 129I / 127I ratios in crater
lake and hot spring at Zao volcano, Miyagi Prefecture

T. Matsunaka, K. Sasa, K. Sueki, N. Shibayama, T. Takahashi, M. Matsumura, Y. Satou, H. Matsuzaki 1, A.
Goto 2, T. Watanabe 3, N. Tsutchiya3, N. Hirano3 and A. Kizaki 4
Volcanic tremors and mountain gradient changes have been detected at Zao volcano in Miyagi since
January 2013, volcanic activity has become higher after the 2011 Tohoku Earthquake although the volcano
will not erupt immediately [1]. Basic water quality of crater lake and hot spring at Zao volcano have beenstudied by the group of Tohoku University from September 2013 since the water quality of crater lake arecorrelating with volcanic activity [2] [3]. As a part of this project, we are trying to monitor the volcanic
activity using 129I / 127I ratios (atomic ratio of radioiodine and stable iodine) in crater lake and hot spring of
Zao volcano. Natural 129I (half-life: 15.7 million year) are produced by nuclear spallation reaction of 129Xe
with cosmic ray in the atmosphere and spontaneous fission of 238U in the geological layer. In the ocean,steady-state 129I / 127I ratio of the seawater is estimated to be 1.5 × 10-12 [4]. Sunken iodine by the ocean
plate having lower 129I / 127I ratio (older 129I age) compared to the steady-state ratio of seawater, aresupplied to the atmosphere mainly via magmatic activity. In general, 129I / 127I ratio in hot spring water andbrine water are used as indicator of origin and behavior of iodine in the groundwater [5] [6]. 129I / 127I ratio ofhydrothermal at Zao volcano are considered to become lower by the supply of chronologically-old iodine
in terms of global iodine cycle.

A)

B)
Fig.1. Photographs of sampling sites; A: Okama (crater lake), B: Kamoshika Hot Spring.

In September 2013, water samples of 2 L were collected from the surface of crater lake (Okama,diameter: 350 m, maximum depth: 35 m) located at 1,560 m in elevation and hot spring (Kamoshika Hot
Spring) located at 1,230 m in elevation in the eastern side of Zao volcano (Fig.1). Water temperature andpH were measured on site. After water samples were filtered by 0.2 µm filter, 129I / 127I ratio were
measured by AMS for the isotopic diluted water samples adding carrier (127I standard) at MALT, The
1

MALT, The University of Tokyo
Center for Northeast Asian Studies, Tohoku University
3
Graduate school of Environmental Studies, Tohoku University
4
Faculty of Engineering and Resource Science, Akita University
229

University of Tokyo. 127I concentrations were measured by ICP-MS, and original 129I / 127I ratio of water
samples were estimated (Fig.2).
Water temperature and pH were 10.2℃ and 3.3 at Okama; 40.0℃ and 3.3 – 4.0 at Kamoshika Hot
Spring. 129I / 127I ratios of Okama and Kamoshika Hot Spring were respectively, estimated to be (1.5 ± 0.4)
× 10-9 and (0.78 ± 0.15) × 10-9, 500 – 1,000 times higher than the steady-state ratio of sea water (1.5 ×
10-12) [4]. Since 129I / 127I ratio of anthropogenic metric water were over 9.0 × 10-12 [7], surface water ofOkama and Kamoshika Hot Spring water were very likely to be strong affected by the meteoric water
including anthropogenic 129I. For the monitoring of volcanic activity using 129I / 127I ratio, it is necessary to
decide the site as few anthropogenic 129I as possible through the measuring of 129I / 127I ratio of the Okama
bottom water and some hot spring around Zao volcano. Continuous water quality survey of 1 time for
Okama and 1 time per 2 months for hot springs are planned for this year.

Fig.3. 129I / 127I ratios of Okama (crater lake)and Kamoshika Hot Spring at September
Fig.2. Sample preparation of water for the determinations

2013; red dashed line: 129I / 127I ratio ofof stable iodine (127I) by ICP-MS and 129I / 127I rations

anthropogenic metric water, blue dashedby AMS.

line: 129I / 127I ratio of sea water.

References[1] Japan Meteorological Agency, (2013) Monthly Volcanic Activity Report.
[2] Ohba et al., (2000) Journal of Volcanology and Geothermal Research, 97, 329-346.
[3] Ohba et al., (2008) Journal of Volcanology and Geothermal Research, 178, 131-144.
[4] Moran et al., (1998) Chemical Geology, 152, 193-203.
[5] Snyder and Fehn, (2002) Geochimica et Cosmochimica Acta, 66, 3827-3838.
[6] Muramatsu et al., (2001) Earth and Planetary Science Letter, 192, 583-593.
[7] Tomaru et al., (2007) Applied Geochemisty, 22, 676-691.

30

4.3

Successive searches of 129I contamination in the chemical sample
preparation room

M. Matsumura, K. Sasa, K. Sueki, N. Shibayama, T. Matsunaka, T. Takahashi, Y. Satou and H. Matsuzaki 1
We have addressed measurements of trace radionuclides such as 36Cl and 129I by AMS. It is importantthat the sample preparation room must be kept clean for accurate measurement. “Clean” means that it isfar from not only visible state but also invisible contamination including isobars of interests. The
contamination induces confusion in experimental results for AMS. However, the sample preparation room
tends to be gradually contaminated in the process of chemical treating with a high concentration ofradionuclides. Especially, halogen family of elements have volatile species, and contaminant diffusion
occurs in the sample preparation room easily. In this work, we show the extent of contamination in thesample preparation rooms over time, particularly pertaining to 129I.
Alkaline trap solutions were placed in the several sample preparation rooms with each three weeks, atUniversity of Tsukuba Tandem Accelerator Complex (UTTAC) and Center for Research in Isotopes andEnvironmental Dynamics (CRiED). After the iodine carrier was added to the part of trap solutions, thetrapped iodine was collected as AgI via chemical purification. Concentrations of 129I in the trap solutions
were measured with the AMS at MALT, the University of Tokyo [1]. In three month intervals, the 129I
concentrations in the trap solutions were determined to be 103 to 104 atoms g-1 in the room where soil
samples from Fukushima have been treated at UTTAC. On the other hand, we get results of 129I
concentrations in trap solutions lower than 103 atoms g-1 in the room where we have only treated samples
for final purification at UTTCA, too. Besides, we find the results of highly 129I contamination ranging
from 105 to 106 atoms g-1 in the room where we treated the neutron-activated iodine at CRiED. The
experimental results showed that levels of the 129I contaminations depend on ambient environmental
conditions in the sample preparation room (Table 1. and Fig. 1).

1

MALT, The University of Tokyo

31

Table 1. Measurement of 129I/127I ratio in different rooms by AMS
Room No.

MT dateI (atom g -1)

I/127I (×10 -12)

129

129

I/127I (×10 -9)1292013/8/11

1.3

±

0.0

1.9×104±

0.1×104

39±

5

2013/11/3

0.78

±

0.13

6.1×103±

3.6×103

7.2

±

4.8

2013/8/11

0.59

±

0.024

1.9×103±

1×103

2013/11/3

0.36

±

0.03

2013/8/11

3.0

±

0.1

6.2×104±

0.2×104

4.7×102±2.4×1022013/11/3

4.96

±

0.52

1.1×105±

0.1×104

1.4×102±

0.3×102

C210

2013/11/3

0.84

±

0.06

7.0×103±

1.7×103

3.3

±

0.8

CRiED hotroom

2013/11/3

62

±

2

1.5×106±

0.05×106

1.2

±

0.2

C108

C209

CRiED cold
room

N.D.

N.D.

N.D.

Note: 129I/127I ratios were normalized by Purdue STD (63.6×10-12) in the measurement. The amount of carrier was 2 mg.
The carrier solution was produced by Orion ionplusR（Thermo Fisher Scientific, USA). The 129I/127I ratios of this carrier reported were around 1.7
×10-12 [2].

Fig.1. Comparison of 129I/127I ratios of the different rooms.
References[1] Matsuzaki, H. et al., Nucl. Instr. and Meth. B 259 (2007) 721.
[2] Muramatsu, Y. et al., Quat.Geochro. 3(2008) 291.

32

4.4

Comparison between 36Cl-AMS simulations using PHITS code andexperiments

D. Izumi, K. Sasa, T. Takahashi, T. Matsunaka, Y. Satou, M. Matsumura, K. Sueki, M. Kinoshita 1,
Y. Miyake 2 and H. Matsuzaki2
Update of the tandem accelerator is planned in the University of Tsukuba Tandem Accelerator Complex(UTTAC). Our group had worked on applied studies using 36Cl-AMS with an old accelerator system. The
maximum terminal voltage will fall down from 12 MV to 6 MV due to the update. We have investigated amaterial of window and gas pressure of a gas ionization detector because separation of isobars depends onenergy of projectile and these detector condition. As the first step of that purpose, we simulated energy
spectrum and the energy loss of 36Cl in the detector using PHITS code (Particle and Heavy Ion Transport
code System) [1] and results of the simulation were compared with those performed at MALT, theUniversity of Tokyo. As shown in experimental results (Fig. 1), 36Cl couldn’t be separated completelyfrom 36S on two-dimensional spectrum.
Ions of 36Cl7+ with 40 MeV were measured with the gas ionization detector which was filled with 60 Torr
P10 gas (Ar 90% +CH4 10%). A 3 µm of Mylar foil was used in the detector window. We obtained
two-dimensional energy spectra of 36Cl and 36S. On the other hand, the spectra were compared withsimulations using PHITS code. As a spectrum is seen in Fig. 2, the simulation showed that tail of 36Sinterfered detection of 36Cl. The tail would be caused by multiple scattering in the Mylar foil. To avoid
multiple scattering, If a 150-nm-thick-silicon nitride foil (Si3N4) is used in the detector window, thescattering would be avoided because of its small energy loss [2]. As a spectrum is seen in Fig. 3, theseresults and more analysis of detector condition for optimization using the simulation would allow us toseparate the isobars in the 36Cl-AMS. As a result of simulation in Fig. 3, the silicon nitride entrance
window will apply the new 36Cl-AMS system at UTTAC.

Fig.1. Two-dimensional spectrum of AMS for
40-MeV-36Cl and 36S performed at MALT.
1

Institute of technology, Shimizu Co.

2

MALT, the University of Tokyo

33

Fig.2. Two-dimensional spectrum for36

Fig.3. Two-dimensional spectrum for

36

40-MeV- Cl and S with 3-µm-thick-Mylar

40-MeV-36Cl and 36S with 150-nm-thick-silicom

foil simulated using PHITS code.

nitride foil simulated using PHITS code.

References[1] T. Sato, K. Niita, N. Matsuda, S. Hashimoto, Y. Iwamoto, S. Noda, T. Ogawa, H. Iwase, H. Nakashima,
T. Fukahori, K. Okumura, T. Kai, S. Chiba, T. Furuta and L. Sihver, Particle and Heavy Ion Transport
Code System PHITS, Version 2.52, J. Nucl. Sci. Technol. 50, 913–923 (2013).
[2] C. Maden, P.A.F. Anastasi, A. Dougans, S.P.H.T. Freeman, R. Kitchen, G. Klody, C. Schnabel, M.
Sundquist, K. Vanner, S. Xu, SUERC AMS ion detection, Nucl. Instr. Meth. B 259, 131–139 (2007).

34

4.5

Distribution of 129I in the environment released from the FDNPP
accident and estimation of 131I/129I ratio

K. Sasa, M. Matsumura, M. Matsunaka, T. Takahashi, Y. Satou, K. Sueki, N. Kinoshita 1
and H. Matsuzaki 2
Radioiodine is one of the most important radionuclides released from the Fukushima-Daiichi
Nuclear Power Plant (FDNPP) accident. 131I (half-life: 8 d) has a short half life time. We measured 131I
concentrations in surface soils by a gamma-ray measurement immediately after the FDNPP accident at
108 sites in Fukushima and the Kanto area [1]. Because of the difficulty of measuring 131I at this time, it isexpected to estimate 131I precipitation from 129I (half-life: 1.57 × 107 y) with the long half-life in surface
soils. Therefore, it is necessary to know the isotopic ratio of 131I/129I released from the FDNPP accident forreconstruction of 131I. 129I/127I ratio was measured by accelerator mass spectrometry (AMS) at MALT, theUniversity of Tokyo [2]. Stable iodine of 127I was determined by inductively coupled plasma mass
spectrometry (ICP-MS). We got a result that the average of 129I concentration was (2.74 ± 1.35) × 108
atoms/g prior to the FDNPP accident as 129I background data at Fukushima. After the FDNPP accident, theweighted average of 131I /129I ratios is estimated to (4.02 ± 0.81) × 10-2 at Fukushima as at March 11, 2011.
Fig. 1 shows a correlation between 129I and 131I in surface soils. The calculation results of 131I/129I ratio
made by ORIGEN 2.2 code [3] are 3.18 × 10-2 for the Unit 1, 4.57 × 10-2 for the Unit 2 and 4.81 × 10-2 for
the Unit 3. They are consistent with the measured results of 131I /129I ratio.

Figure 1. Correlation between 129I and 131I in surface soils at Fukushima as at March 11, 2011. Black line
shows the weighted average of 131I/129I ratios. Dashed line indicates the standard deviation of 1σ.
References[1] Norikazu Kinoshita, Keisuke Sueki, Kimikazu Sasa et al., PNAS, 108 (2011) 19526-19529.
[2] Hiroyuki Matsuzaki et al., Nucl. Instr. Meth. Phys. Res. B 259, (2007) 721-726.
[3] Kenji Nishihara, JAEA-Data/Code 2012-018.
1
2

Shimizu Co.
MALT, The University of Tokyo

35

4.6

Technological development for Strontium-90 determination using AMS

Y. Satou, K. Sueki, K. Sasa, T. Matsunaka, T. Takahashi, N. Shibayama, D. Izumi, N. Kinoshita 1 and H.
Matsuzaki 2
Strontium-90 (90Sr) is a fission product and expected to be released into the environment through suchas a nuclear accident. 90Sr quantities are usually measured by chemical isolation of Sr from environmental
samples followed by low-level beta counting, however, there are complicated and time-consuming
processes to determine 90Sr. Rapid and simple processes are highly required to evaliate 90Sr quantities,
especially after the nuclear disaster. The Accelerator Mass Spectrometry (AMS) is one of potential
methods which would solve these problems. We have attempted to develop the 90Sr-AMS using the 5 MV
tandem accelerator at MALT, the University of Tokyo. We report production tests of negative ion beams
and detection tests of 90Zr with the AMS techniques for effective 90Sr measurements. Target samples of
SrF2 were made with chemical separation from the soil at Fukushima. Mixed samples with the purified
SrF2 and PbF2 were pressed in the aluminum sample holder and installed in the MC-SNICS ion source.
The negative ions of 88SrF3- with over 500 nA were successfully extracted from the MC-SNICS ion source.
Natural isobar of 90Zr interferes with 90Sr detection using an ionization chamber. However, in order toobserve the behavior of the 90Sr in gas counter, 90Zr isobar was monitored as 90Sr in this study. After theions passed through a gas stripper, the ions with 90 for mass number and 6+ for charge state, which areconsidered to be 90Zr, were transported to an ionization chamber. The ions with 1000 cps for count rate
were identified in the two-dimensional spectrum in Fig. 1, which correspond to approximately 3 × 10-8 foratom ratio of 90Zr/88Sr in the Sr beam. Further works would provide a successful isobaric separation.

Fig.1 Spectrum of90

Zr6+ on gas counter.

1
2

Institute of Technology, Shimizu Corporation
MALT, The University of Tokyo

36

5.

LIST OF PUBLICATIONSACCELERATOR AND EXPERIMENTAL FACILITIES
1.

K. Sasa, “The 6 MV tandem accelerator project for nuclear physics and ion beam applications at the
University of Tsukuba”, AIP Conf. Proc.1533,184 (2013).

NUCLEAR PHYSICS
2.

L.Y. Zhang, J.J. He, A. Parikh, S.W. Xu, H. Yamaguchi, D. Kahl, S. Kubono, P. Mohr, J. Hu, P. Ma,
S.Z. Chen, Y. Wakabayashi, H.W. Wang, W.D. Tian, R.F. Chen, B. Guo, T. Hashimoto, Y. Togano, S.
Hayakawa, T. Teranishi, N. Iwasa, T. Yamada, T. Komatsubara, Y.H. Zhang, X.H. Zhou,“Investigation of the thermonuclear 18Ne(α, p)21Ne reaction rate via resonant elastic scattering of 21Na
+ p”, Phys. Rev. C 89, 015804 (2014).

3.

S.J. Jin, Y.B. Wang, J. Su, S.Q. Yan, Y.J. Li, B. Guo, Z.H. Li, S. Zeng, G. Lian, X.X. Bai, W.P. Liu, H.
Yamaguchi, S. Kubono, J. Hu, D. Kahl, H.S. Jung, J.Y. Moon, C.S. Lee, T. Teranishi, H.W. Wang, H.
Ishiyama, N. Iwasa, T. Komatsubara, B.A. Brown, “Resonant scattering of

22

Na + p studied by the

thick-target inverse-kinematic method”, Phys. Rev. C 88, 035801 (2013).
4.

J.J. He, L.Y. Zhang, A. Parikh, S.W. Xu, H. Yamaguchi, D. Kahl, S. Kubono, J. Hu, P. Ma, S.Z. Chen,
Y. Wakabayashi, B.H. Sun, H.W. Wang, W.D. Tian, R.F. Chen, B. Guo, T. Hashimoto, Y. Togano, S.
Hayakawa, T. Teranishi, N. Iwasa, T. Yamada, T. Komatsubara, “The 18Ne(α, p)21Na breakout
reaction in x-ray bursts: Experimental determination of spin-parities for α resonances in 22Mg via
resonant elastic scattering of 21Na + p”, Phys. Rev. C 88, 012801(R) (2013).

5.

C.B. Moon, T. Komatsubara, K. Furuno, “Level structure of 154Ho”, Phys. Rev. C 88, 044308 (2013).

6.

K. Setoodehnia, A.A. Chen, D. Kahl, T. Komatsubara, J. Jose, R. Longland, Y. Abe, D.N. Binh, J.
Chen, S. Cherubini, J.A. Clark, C.M. Deibel, S. Fukuoka, T. Hashimoto, T. Hayakawa, J. Hendriks, Y.
Ishibashi, Y. Ito, S. Kubono, W.N. Lennard, T. Moriguchi, D. Nagae, R. Nishikiori, T. Niwa, A.
Ozawa, P.D. Parker, D. Seiler, T. Shizuma, H. Suzuki, C. Wrede, H. Yamaguchi, T. Yuasa, “Nuclear
structure of 30S and its implications for nucleosynthesis in classical novae”, Phys. Rev. C 87, 065801(2013).

7.

T. Onishi, T. Komatsubara, T. Yuasa, K. Sasa, A. Ozawa, D. Izumi, M. Mukai, S. Kubono, T.
Hayakawa, T. Shizuma, “Study of nucleosynthesis by means of 45Sc + p reaction”, JPS (The Physical37

Society of Japan) Conf. Proc. 1, 013054 (2014).
8.

T. Komatsubara, T. Yuasa, T. Onishi, Y. Saito, S. Okada, K. Sasa, A. Ozawa, T. Hayakawa, T.
Shizuma, T. Kajino, S. Kubono, ”Study for big bang nucleosynthesis concerning lithium isotopes”,
JPS (The Physical Society of Japan) Conf. Proc. 1, 013055 (2014).

9.

K. Setoodehnia, A. A. Chen, D. Kahl, T. Komatsubara, J. Jos, R. Longland, Y. Abe, D. N. Binh, J.
Chen, S. Cherubini, J. A. Clark, C. M. Deibel, S. Fukuoka, T. Hashimoto, T. Hayakawa, J. Hendriks,
Y. Ishibashi,Y. Ito, S. Kubono, W. N. Lennard, T. Moriguchi, D. Nagae, R. Nishikiori, T. Niwa, A.
Ozawa, P. D . Parker, D. Seiler, T. Shizuma, H. Suzuki, C. Wrede, H. Yamaguchi, T. Yuasa,“Nuclear structure of 30S and its implications for nucleosynthesis in classical novae”, Phys. Rev. C 87,
065801 (2013).

10. Y. Ito, P. Schury, M. Wada, S. Naimi, T. Sonoda, H. Mita, F. Arai, A. Takamine, K. Okada, A.
Ozawa, H. Wollnik, “Single-reference high-precision mass measurement with a multireflection
time-of-flight mass spectrograph”, Phys. Rev. C 88, 011306(R) (2013).
11. T. Moriguchi, A. Ozawa, S. Ishimoto, Y. Abe, M. Fukuda, I. Hachiuma, Y. Ishibashi, Y. Ito, T.
Kuboki, M. Lantz, D. Nagae, K. Namihira, D. Nishimura, T. Ohtsubo, H. Ooishi, T. Suda, H. Suzuki,
T. Suzuki, M. Takechi, K. Tanaka, T. Yamaguchi, “Density distributions of 11Li deduced fromreaction cross-section measurements”, Phys. Rev. C 88, 024610 (2013).
12. H.J. Ong, I. Tanihata, A. Tamii, T. Myo, K. Ogata, M. Fukuda, K. Hirota, K. Ikeda, D. Ishikawa, T.
Kawabata, H. Matsubara, K. Matsuta, M. Mihara, T. Naito, D. Nishimura, Y. Ogawa, H. Okamura,A. Ozawa, D. Y. Pang, H. Sakaguchi, K. Sekiguchi, T. Suzuki, M. Taniguchi, M. Takashina, H. Toki,
Y. Yasuda, M. Yosoi, J. Zenihiro, “Probing effect of tensor interactions in 16O via (p,d) reaction”,
Phys. Let. B 725,277 (2013).
13. T. Yamaguchi, Y. Yamaguchi, A. Ozawa, “The challenge of precision mass measurements ofshort-lived exotic nuclei, “Development of a new storage ring mass spectrometry”, Int. J. of Mass
Spectrometry 349–350, 240 (2013).
14. Yu.A. Litvinov, S. Bishop, K. Blaum, F. Bosch, C. Brandau, L.X. Chen, I. Dillmann, P. Egelhof, H.
Geissel, R.E. Grisenti, S. Hagmann, M. Heil, A. Heinz, N. Kalantar-Nayestanaki, R. Knoobel, C.
Kozhuharov, M. Lestinsky, X.W. Ma, T. Nilsson, F. Nolden, A. Ozawa, R. Raabe, M.W. Reed, R.
Reifarth, M.S. Sanjari, D. Schneider, H. Simon, M. Steck, T. Stoohlker, B.H. Sun, X.L. Tu, T.
Uesaka, P.M. Walker, M. Wakasugi, H. Weick, N. Winckler, P.J. Woods, H.S. Xu, T. Yamaguchi, Y.
Yamaguchi, Y.H. Zhang, “Nuclear physics experiments with ion storage rings”, Nucl. Instrum. Meth.
Phys. Res. B 317, 603 (2013).

38

15. Y. Yamaguchi, M. Wakasugi, T. Uesaka, A. Ozawa, Y. Abe, T. Fujinawa, M. Kase, M. Komiyama, T.
Kubo, K. Kumagai, T. Maie, D. Nagae, J. Ohnishi, F. Suzaki, A. Tokuchi, Y. Watanabe, K. Yoshida,
K. Yamada, T. Yamaguchi, H. Yamasawa, Y. Yanagisawa, J. Zenihiro, Y. Yano, “Construction of
rare-RI ring at RIKEN RI Beam Factory”, Nucl. Instrum. Meth. Phys. Res. B 317, 629 (2013).
16. F. Suzaki, J. Zenihiro, T. Yamaguchi, A. Ozawa, T. Uesaka, M. Wakasugi, K. Yamada, Y.
Yamaguchi, Rare-RI Ring collaboration, “Design study of a resonant Schottky pick-up for the
Rare-RI Ring project”, Nucl. Instrum. Meth. Phys. Res. B 317, 636 (2013).
17. D. Nagae, Y. Abe, S. Okada, A. Ozawa, T. Yamaguchi, H. Suzuki, T. Moriguchi, Y. Ishibashi, S.
Fukuoka, R. Nishikiori, T. Niwa, T. Suzuki, F. Suzaki, K. Sato, H. Furuki, N. Ichihashi, S. Miyazawa,
Y. Yamaguchi, T. Uesaka, M. Wakasugi, “Time-of-flight detector applied to mass measurements in
Rare-RI Ring”, Nucl. Instrum. Meth. Phys. Res. B 317, 640 (2013).
18. T. Yamaguchi, F. Suzaki, T. Izumikawa, S. Miyazawa, K. Morimoto, T. Suzuki, F. Tokanai, H.
Furuki, N. Ichihashi, C. Ichikawa, A. Kitagawa, T. Kuboki, S. Momota, D. Nagae, M. Nagashima, Y.
Nakamura, R. Nishikiori, T. Niwa, T. Ohtsubo, A. Ozawa, K. Sato, S. Sato, S. Suzuki, “Performanceof high-resolution position-sensitive detectors developed for storage-ring decay experiments”, Nucl.
Instrum. Meth. Phys. Res. B 317, 697 (2013).
19. S. Yamaki, T. Yamaguchi, J. Kouno, K. Sato, N. Ichihashi, T. Suzuki, K. Abe, Y. Abe, M. Fukuda, H.
Furuki, N. Inaba, K. Iwamoto, T. Izumikawa, Y. Kamisho, N. Kikuchi, A. Kitagawa, M. Mihara, S.
Miyazawa, S. Momota, Y. Morita, D. Nagae, M. Nagashima, Y. Nakamura, R. Nishikiori, D.
Nishimura, I. Nishizuka, T. Ohtsubo, J. Ohno, A. Ozawa, T. Sakai, S. Sato, D. Sera, F. Suzaki, S.
Suzuki, S. Suzuki, M. Wakabayashi, M. Yaguchi, S. Yasumoto, “Systematic study of individual
charge-changing cross sections of intermediate-energy secondary beams”, Nucl. Instrum. Meth. Phys.
Res. B 317, 774 (2013).
20. Y. Ishibashi, N. Yoshida, H. Ueno, A. Yoshimi, Y. Ichikawa, Y. Abe, K. Asahi, M. Chikamori, T.
Fujita, T. Furukawa, E. Hikota, D. Nagae, Y. Ohtomo, Y. Saito, H. Shirai, T. Suzuki, X.F. Yang, N.
Sakamoto, “Development of an adiabatic field rotation system to measure spin polarization of
unstable nuclei”, Nucl. Instrum. Meth. Phys. Res. B 317, 714 (2013).
21. Y. Ishibashi, D. Nagae, Y. Abe, T. Nagatomo, A. Ozawa, H. Suzuki, S. Fukuoka, R. Nishikiori, T.
Niwa, K. Matsuta, Y. Tagishi, "Production of nuclear polarization of unstable nuclei via polarizationtransfer reactions", Hyperfine Interact. 220, 71 (2013).

39

22. N. Yoshida, H. Ueno, A. Yoshimi, Y. Ishibashi, Y. Ichikawa, Y. Abe, K. Asahi, M. Chikamori, T.
Fujita, T. Furukawa, E. Hikota, D. Nagae, Y. Ohtomo, Y. Saito, H. Shirai, T. Suzuki, X.F. Yang,“Development of a new device control system for β-NMR experiments”, Nucl. Instrum. Meth. Phys.
Res. B 317, 705 (2013).
23. X.F. Yang, T. Furukawa, T. Wakui, K. Imamura, H. Tetsuka, T. Fujita, Y. Yamaguchi, Y. Tsutsui, Y.
Mitsuya, Y. Ichikawa, Y. Ishibashi, N. Yoshida, H. Shirai, Y. Ebara, M. Hayasaka, S. Arai, S.
Muramoto, A. Hatakeyama, M. Wada, T. Sonoda, Y. Ito, T. Kobayashi, S. Nishimura, M. Nishimura,
Y. Kondo, K. Yoneda, H. Ueno, T. Shinozuka, T. Shimoda, K. Asahi, Y. Matsuo, “Control ofstopping position of radioactive ion beam in superfluid helium for laser spectroscopy experiments”,
Nucl. Instrum. Meth. Phys. Res. B 317, 599 (2013).
24. D. Nagae, T. Niwa, Y. Ishibashi, Y. Abe, S. Fukuoka, R. Nishikiori, S. Okada, Y. Saito, N. Inaba, A.
Ozawa, Y. Aoki, “Development of rotating magnetic field system for the β-NMR method”, The 4th
Joint Meeting of the International Symposium on Hyperfine Interactions and the International
Symposium on Nuclear Quadrupole Interactions (HFI/NQI 2012) Hyperfine Interact. 220, 65-69(2013).
25. M. Mihara, K. Matsuta, D. Nishimura, M. Fukuda, M. Yaguchi, K. Iwamoto, M. Wakabayashi, Y.
Kamisho, J. Ohno,Y. Morita, T. Izumikawa, T. Ohtsubo, S. Suzuki, M. Nagashima, K. Abe, T. Sakai,
S. Momota, A. Ozawa, D. Nagae,Y. Ishibashi, Y. Abe, T. Niwa, T. Nagatomo, T. Minamisono, M. K.
Kubo, A. Kitagawa, M. Torikoshi, M. Kanazawa , S. Sato, ”Production of spin polarized 12N throughheavy ion reactions”, The 4th Joint Meeting of the International Symposium on Hyperfine
Interactions and the International Symposium on Nuclear Quadrupole Interactions (HFI/NQI 2012)
Hyperfine Interact. 220, 83 (2013).
26. Y. Yamaguchi , M. Wakasugi, T. Uesaka, A. Ozawa, Y. Abe, T. Fujinawa, M. Kase, M. Komiyama, T.
Kubo, K. Kumagai, T. Maie, D. Nagae, J. Ohnishi, F. Suzaki, A. Tokuchi, Y. Watanabe, K. Yoshida, K.
Yamada, T. Yamaguchi, H. Yamasawa, Y. Yanagisawa, J. Zenihiro, Y. Yano, “Construction of rare-RI
ring at RIKEN RI Beam Factory”, Proceedings of the XVIth International Conference on
Electromagnetic Isotope Separators and Techniques Related to their Applications, Nucl. Instrum.
Meth. Phys. Res. B 317, 629 (2013).
27. D. Nagae, Y. Abe, S. Okada, A. Ozawa, T. Yamaguchi, H. Suzuki, T. Moriguchi, Y. Ishibashi, S.
Fukuoka, R. Nishikiori, T. Niwa, T. Suzuki, F. Suzaki, K. Sato, H. Furuki, N. Ichihashi, S. Miyazawa,
Y. Yamaguchi, T. Uesaka, M. Wakasugi, “Time-of-flight detector applied to mass measurements in
Rare-RI Ring”, Proceedings of the XVIth International Conference on Electromagnetic Isotope
Separators and Techniques Related to their Applications, Nucl. Instrum. Meth. Phys. Res. B 317, 640(2013).

40

28. T. Yamaguchi, F. Suzaki, T. Izumikawa, S. Miyazawa, K. Morimoto, T. Suzuki, F. Tokanai, H. Furuki,
N. Ichihashi, C. Ichikawa, A. Kitagawa, T. Kuboki, S. Momota, D. Nagae, M. Nagashima, Y.
Nakamura, R. Nishikiori, T. Niwa, T. Ohtsubo, A. Ozawa, K. Sato, S. Sato, S. Suzuki, “Performanceof high-resolution position-sensitive detectors developed for storage-ring decay experiments”,
Proceedings of the XVIth International Conference on Electromagnetic Isotope Separators andTechniques Related to their Applications, Nucl. Instrum. Meth. Phys. Res. B 317, 697 (2013).
29. N. Yoshida, H. Ueno, A. Yoshimi, Y. Ishibashi, Y. Ichikawa, Y. Abe, K. Asahi, M. Chikamori, T. Fujita,
T. Furukawa, E. Hikota, D. Nagae, Y. Ohtomo, Y. Saito, H. Shirai, T. Suzuki, X.F. Yang,“Development of a new device control system for β-NMR experiments”, Proceedings of the XVIthInternational Conference on Electromagnetic Isotope Separators and Techniques Related to their
Applications, Nucl. Instrum. Meth. Phys. Res. B 317, 705 (2013).
30. Y. Ishibashi, N. Yoshida, H. Ueno, A. Yoshimi, Y. Ichikawa, Y. Abea, K. Asahi, M. Chikamori, T.
Fujita, T. Furukawa, E. Hikota, D. Nagae, Y. Ohtomo, Y. Saito, H. Shirai, T. Suzuki, X.F. Yang, N.
Sakamoto, “Development of an adiabatic ﬁeld rotation system to measure spin polarization of
315unstable nuclei”, Proceedings of the XVIth International Conference on Electromagnetic Isotope
Separators and Techniques Related to their Applications, Nucl. Instrum. Meth. Phys. Res. B 317, 714(2013).
31. S. Yamaki, T. Yamaguchi, J. Kouno, K. Sato, N. Ichihashi, T. Suzuki, K. Abe, Y. Abe, M. Fukuda, H.
Furuki, N. Inaba, K. Iwamoto, T. Izumikawa, Y. Kamisho, N. Kikuchi, A. Kitagawa, M. Mihara, S.
Miyazawa, S. Momota, Y. Morita, D. Nagae, M. Nagashima, Y. Nakamura, R. Nishikiori, D.
Nishimura, I. Nishizuka, T. Ohtsubo, J. Ohno, A. Ozawa, T. Sakai, S. Sato, D. Sera, F. Suzaki, S.
Suzuki, S. Suzuki, M. Wakabayashi, M. Yaguchi, S. Yasumoto, “Systematic study of individual
charge-changing cross sections of intermediate-energy secondary beams”, Proceedings of the XVIthInternational Conference on Electromagnetic Isotope Separators and Techniques Related to their
Applications, Nucl. Instrum. Meth. Phys. Res. B 317, 774 (2013).
32. A.S. Demyanova, A.A. Ogloblin, A.N. Danilov, S.V. Dmitriev, S.A. Goncharov, N. Burtebaev, J.
Burtebaeva,N. Saduev, T.L. Belyaeva, H. Suzuki, A. Ozawa, Y. Abe, S. Fukuoka, Y. Ishibashi, S. Ito,
T. Komatsubara,T. Moriguchi, D. Nagae, R. Nishikiori, T. Niwa, K. Okumura, H. Ooishi, K.
Yokoyama and S. Kubono, ”Spectroscopy of 9Be and observation of neutron halo structure in thestates of positive parity rotational band”, Proceedings of International Nuclear Physics Conference,
EPJ Web of Conferences 66, 02026 (2014).
33. M. Takechi, S. Suzuki, D. Nishimura, M. Fukuda, T. Ohtsubo, M. Nagashima, T. Suzuki, T.
Yamaguchi,A. Ozawa, T. Moriguchi, H. Ohishi, T. Sumikama, H. Geissel, M. Ishihara, N. Aoi,

41

Rui-Jiu Chen,De-Qing Fang, N. Fukuda, S. Fukuoka, H. Furuki, N. Inabe, Y. Ishibashi, T. Itoh, T.
Izumikawa, D. Kameda, T. Kubo, C. S. Lee, M. Lantz, Yu-Gang Ma, K. Matsuta, M. Mihara, S.
Momota, D. Nagae, R. Nishikiori,T. Niwa, T. Ohnishi, K. Okumura, T. Ogura, H. Sakurai, K. Sato, Y.
Shimbara, H. Suzuki, H. Takeda,S. Takeuchi, K. Tanaka, H. Uenishi, M. Winkler, Y. Yanagisawa, S.
Watanabe, K. Minomo, S. Tagami,M. Shimada, M. Kimura, T. Matsumoto, Y. R. Shimizu and M.
Yahiro,“Search for halo nucleus in Mg isotopes through the measurements of reaction cross sections
towards the vicinity of neutron drip line”, Proceedings of International Nuclear Physics Conference,
EPJ Web of Conferences 66, 02101 (2014).
34. S. Suzuki, M. Takechi, T. Ohtsubo, D. Nishimura, M. Fukuda, T. Kuboki, M. Nagashima, T. Suzuki,
T. Yamaguchi, A. Ozawa, H. Ohishi, T. Moriguchi, T. Sumikama, H. Geissel, N. Aoi, Rui-Jiu
Chen,De-Qing Fang, N. Fukuda, S. Fukuoka, H. Furuki, N. Inabe, Y. Ishibashi, T. Ito, T. Izumikawa,D. Kameda,T. Kubo, M. Lantz, C.S. Lee, Yu-Gang Ma, M. Mihara, S. Momota, D. Nagae, R.
Nishikiori, T. Niwa,T. Ohnishi, K. Okumura, T. Ogura, H. Sakurai, K. Sato, Y. Shimbara, H. Suzuki,
H. Takeda, S. Takeuchi,K. Tanaka, H. Uenishi, M. Winkler and Y. Yanagisawa, “Measurements ofinteraction cross sections for 22–35Na isotopes”, Proceedings of International Nuclear Physics
Conference, EPJ Web of Conferences 66, 03084 (2014).
35. M. von Schmid, S. Bagchi, S. Bönig, M. Csatlós, I. Dillmann, C. Dimopoulou, P. Egelhof, V.
Eremin,T. Furuno, H. Geissel, R. Gernhäuser, M. N. Harakeh, A.-L. Hartig, S. Ilieva, N.
Kalantar-Nayestanaki,O. Kiselev, H. Kollmus, C. Kozhuharov, A. Krasznahorkay, T. Kröll, M.
Kuilman, S. Litvinov,Yu. A. Litvinov, M. Mahjour-Shafiei, M. Mutterer, D. Nagae, M. A. Najafi, C.
Nociforo, F. Nolden, U. Popp,C. Rigollet, S. Roy, C. Scheidenberger, M. Steck, B. Streicher, L. Stuhl,
M. Thürauf, T. Uesaka, H. Weick,J. S. Winfield, D. Winters, P. J. Woods, T. Yamaguchi, K. Yue, J.
C. Zamora and J. Zenihiro, ”First EXL experiment with stored radioactive beam: Proton scattering on
56Ni”, Proceedings of International Nuclear Physics Conference, EPJ Web of Conferences 66, 03093(2014).
36. S. Yamaki, J. Kouno, D. Nishimura, M. Nagashima, M. Takechi, K. Sato, K. Abe, Y. Abe, M.
Fukuda,H. Furuki, I. Hachiuma, A. Homma, N. Ichihashi, C. Ichikawa, N. Inaba, T. Ito, K. Iwamoto,T. Izumikawa,Y. Kamisho, N. Kikuchi, S. Kinno, A. Kitagawa, T. Kojima, T. Kuboki, M. Mihara, S.
Miyazawa, S. Momota, Y. Morita, D. Nagae, Y. Nakamura, K. Namihira, R. Nishikiori, I. Nishizuka,
T. Niwa, M. Ogura, Y. Ohkuma, T. Ohtsubo, S. Okada, J. Ohno, A. Ozawa, Y. Saito, T. Sakai, S.
Sato, D. Sera, F. Suzaki, S. Suzuki, S. Suzuki, T. Suzuki, M. Taguchi, H. Uenishi, M. Wakabayashi,
D. Watanabe, M. Yaguchi, S. Yasumoto andT. Yamaguchi, ”Charge-changing interactions probing
point-proton radii of nuclei”, Proceedings of International Nuclear Physics Conference, EPJ Web ofConferences 66, 03099 (2014).

4237. Y. Abe, D. Nagae, the Rare-RI Ring collaboration,”Developments of time-of-ﬂight detectors for
Rare-RI Ring”, JPS Conf. Proc. 1, 013059 (2014).
38. H. Tsuchida, T. Majima, S. Tomita, K. Sasa, K. Narumi, Y. Saitoh, A. Chiba, K. Yamada, K. Hirata,
H. Shibata, A. Itoh, “Transmission properties of C60 ions through micro- and nano-capillaries”, Nucl.
Instrum. Meth. Phys. Res. B 315, 336 (2013).
39. A. Suzuki, Y. Hirose, D. Oka, S. Nakao, T. Fukumura, S. Ishii, K. Sasa, H. Matsuzaki, T. Hasegawa,“High-Mobility Electron Conduction in Oxynitride: Anatase TaON”, Chem. Mater. 26, 976(2014).

40. T. Onishi, T. Komatsubara, T. Yuasa, K. Sasa, A, Ozawa, D. Izumi, M. Mukai, S. Kubono, T.
Hayakawa and T. Shizuma, “Study of Nucleosynthesis By Means of 45Sc + p Reaction”,
Proceedings of the 12th Asia Pacific Physics Conference, JPS Conf. Proc. 013054 (2014).
41. T. Komatsubara, T. Yuasa, T. Onishi, Y. Saito, S. Okada, K., Sasa, A. Ozawa, T. Hayakawa,T. Shizuma, T. Kajino, S. Kubono, “Study for Big Bang Nucleosynthesis Concerning
Lithium Isotopes”, Proceedings of the 12th Asia Pacific Physics Conference, JPS Conf. Proc.
013055 (2014).
42.

E. Kita, K.Z. Suzuki, Y. Liu, Y. Utsumi, J. Morishita, D. Oshima, T. Kato, T. Niizeki, K. Mibu, H.
Yanagihara, “Magnetization control for bit pattern formation of spinel ferromagnetic oxides by Kr
ion implantation” , J. Appl. Phys. 115, 17B907(2014).

43. E. Kita, K. Ono, N. Yamaguchi, T. Nishihashi, M. Iura, J. Morishita, Y. Utsumi, T. Murakami, K.
Mibu, T. Niizeki, K.Z. Suzuki, H. Yanagihara, “Magnetization control in spinel-type Fe3O4 thin films
by ion implantation”, Jpn. J. Appl. Phys. 53 020306(2014).
44. M. Kishimoto, K. Asai, D. Isaka, H. Yanagihara, Y. Nagasaki, E. Kita, “Magnetic properties inoriented platelet Fe3O4 particles prepared by the polyol method using α-FeOOH as precursors”, J.
Magn. Magn. Mater. 352, 13 (2014).
45. A. Sagara, M. Hiraiwa, A. Uedono, N. Oshima, R. Suzuki, S. Shibata, “Residual defects in low-dose
arsenic-implanted silicon after high-temperature annealing”, Nucl. Instrum. Meth. Phys. Res. B 321,
54 (2014).
46. A. Uedono, S. Murakami, K. Inagaki, K. Iseki, N. Oshima, R. Suzuki, “Characterization ofpolyethylene terephthalate ﬁlms coated with thin AlxSi1−xOy layers using monoenergetic positron
beams”, Thin Solid Films 552, 82 (2013).

43

47. S. Sellaiyan, A. E. Hughes, S. V. Smith, A. Uedono, J. Sullivan, S. Buckman, “Leaching properties ofchromate-containing epoxy films using radiotracers, PALS and SEM”, Prog. Organic Coat. 77, 257(2014).
48. H. Shimizu, S. Nagano, A. Uedono, N. Tajima, T. Momose, Y. Shimogaki, “Material design ofplasma-enhanced chemical vapour deposition SiCH films for low-k cap layers in the further scalingof ultra-large-scale integrated devices-Cu interconnects”, Sci. Tech. Adv. Mat. 44, 055005 (2013).
49. A. Uedono, T. Watanabe, S. Kimura, Y. Zhang, M. Lozac’h, L. Sang, S. Ishibashi, N. Oshima, R.
Suzuki, M. Sumiya, “Vacancy-type defects in InxGa1−xN grown on GaN templates probed using
monoenergetic positron beams”, J. Appl. Phys. 114, 184504 (2013).
50. A. Uedono, P. Verdonck, A. Delabie, J. Swerts, T. Witters, T. Conard, M. R. Baklanov, S. Van
Elshocht, N. Oshima, R. Suzuki, “Characterization of Porous Structures in Advanced Low-k Films
with Thin TaN Layers Using Monoenergetic Positron Beams”, Jpn. Appl. Phys. 52, 106501 (2013).
51. A. Uedono, I. Yonenaga, T. Watanabe, S. Kimura, N. Oshima, R. Suzuki, S. Ishibashi, Y. Ohno,“Vacancy-type defects introduced by plastic deformation of GaN studied using monoenergetic
positron beams”, J. Appl. Phys. 114, 084506 (2013).
52. A. Uedono, T. Kirimura, C. J. Wilson, K. Croes, S. Demuynck, Z. Tőkei, N. Oshima, R. Suzuki,“Vacancy reactions near the interface between electroplated Cu and barrier metal layers studied bymonoenergetic positron beams”, J. Appl. Phys. 114, 074510 (2013).
53. P. Verdonck, A. Maheshwari, J. Swerts, A. Delabie, T. Witters, H. Tielens, S. Dewilde, A. Franquet, J.
Meersschaut, T. Conard, J. L. Prado, S. Armini, M. R Baklanov, S. Van Elshocht, A. Uedono, D. R.
Huanca, S. G. dos Santos, G. Kellerman, “The Effects of Plasma Treatments and Subsequent Atomic
Layer Deposition on the Pore Structure of a k=2.0 Low-k Material”, ECS J. Solid State Sci. Tech. 2
N103 (2013).
54. S. F. Chichibu, T. Onuma, K. Hazu, A. Uedono, “Time-resolved luminescence studies on AlN andhigh AlN mole fraction AlGaN alloys”, Phys. Stat. Sol. C 10, 501 (2013).
55. S. F. Chichibu, H. Miyake, Y. Ishikawa, M. Tashiro, T. Ohtomo, K. Furusawa, K. Hazu, K. Hiramatsu,
A. Uedono, “Impacts of Si-doping and resultant cation vacancy formation on the luminescence
dynamics for the near-band-edge emission of Al0.6Ga0.4N films grown on AlN templates bymetalorganic vapor phase epitaxy”, J. Appl. Phys. 113, 213506 (2013).
56. A. Uedono, S. Ishibashi, N. Oshima, R. Suzuki, “Positron annihilation spectroscopy on nitride-based

44

semiconductors”, Jpn. J. Appl. Phys. 52, 08JJ02 (2013).
57. A. Uedono, T. Tsutsui, T. Watanabe, S. Kimura, Y. Zhang, M. Lozac’h, L. W. Sang, S. Ishibashi, M.
Sumiya, “Point defects introduced by InN alloying into InxGa1−xN probed using a monoenergetic
positron beam”, J. Appl. Phys. 113, 123502 (2013).
58. M. Jiang, D. D. Wang, Z. Q. Chen, S. Kimura, Y. Yamashita, A. Mori, A. Uedono, “Chemical effect of
Si+ ions on the implantation-induced defects in ZnO studied by a slow positron beam”, J. Appl. Phys.
113, 043506 (2013).
59. M. M. Islam, A. Uedono, T. Sakurai, A. Yamada, S. Ishizuka, K. Matsubara, S. Niki, K. Akimoto,“Impact of Se flux on the defect formation in polycrystalline Cu(In,Ga)Se2 thin films grown by threestage evaporation process”, J. Appl. Phys. 113, 064907 (2013).

MATERIALS AND CLUSTER SCIENCE

60. K. Ozeki, D. Sekiba, K.K. Hrakuri, T. Masuzawa, “Antithrombogenicity of Amorphousdeuterated carbon film prepared by RF-plasma CVD”, Nano Biomedinine 5,11 (2013).

45

6.

THESES

Master’s theses
Momo MUKAI

Search for efficient laser resonance ionization schemes of refractory elements
for KISS

Kazuki OSHIMA
Hitomi OZAKI

Long-range angular correlation including forward rapidity detector in
LHC-ALICE p-Pb collisions at √sNN=5.02TeV

Yuta SAITO

Measurements of η dependence of higher harmonic flow for charged hadronin √sNN=200GeV Cu+Au collisions at RHIC-PHENIX
Charge radius of 33Cl deduced from the charge changing cross section

Takahiro ONISHI

Study of 45Sc(p,α)42Ca reaction in low energy region

Taiyo KOBAYASHI

Study on associated low pT hadron production with di-jet in Pb-Pb collisionsat √sNN=2.76 TeV in LHC-ALICE

Shunsuke OKADA

Developments of Time-of-fright detector in Rare RI Ring

Koichi KIHARA

System size dependence of higher harmonic azimuthal anisotropy for charged
hadrons via two-particle correlations at RHIC-PHENIX

Naoto TANAKA

Azimuthally sensitive HBT in √sNN =2.76TeV Pb-Pb collisions at
LHC-ALICE

Naruki INABA

Measurement of the sign of instability jittery magnetic moment by β-NMR
with rotating magnetic field

Kenta CHITO

Development of high-resolution ERDA and resolution estimation by a-C:H
film

Isao HARAYAMA

Development of ∆E-E telescope ERDA for absolute quantification of metal
nitro-oxide nano thin films

Yoko SHIINA

Coincidence measurements of secondary electrons and transmitted ions underirradiation of fast cluster ions

Undergraduate theses
Satomi MAEDA

Detection system development of backscattered particle for channelingexperiments

Yoshihiko YATSU

Development of experimental setup for the zero degree electron spectroscopy
under fast cluster irradiation on carbon thin foils

Ryousuke WATANABE

Coincidence measurements of secondary electrons and transmitted ions underirradiation of fast cluster ions through solid materials

46

7.
2013
Jul 25Aug 8
2014
Jan 20SEMINARS
High-precision mass measurement of short-lived nuclei with a multi-reflection
time-of-flight mass spectrograph, Yuta Ito (University of Tsukuba)
Nuclear structure and space nucleosynthesis, Tetsuro Komatsubara (University of Tsukuba)

Search for efficient laser resonance ionization schemes of refractory elements for KISS,
Momo Mukai (University of Tsukuba)Long-range angular correlation including forward rapidity detector in LHC-ALICE p-Pb
collisions at √sNN=5.02TeV, Kazuki Oshima (University of Tsukuba)

Measurements of η dependence of higher harmonic flow for charged hadron in√sNN=200GeV Cu+Au collisions at RHIC-PHENIX, Hitomi Ozaki (University of Tsukuba

Charge radius of 33Cl deduced from the charge changing cross section, Yuta Saito(University of Tsukuba)
Jan 21

Study of 45Sc(p,α)42Ca reaction in low energy region, Takahiro Onishi (University ofTsukuba)
Study on associated low pT hadron production with di-jet in Pb-Pb collisions at √sNN=2.76
TeV in LHC-ALICE, Taiyo Kobayashi (University of Tsukuba)

Developments of Time-of-fright detector in Rare RI Ring, Shunsuke Okada (University ofTsukuba)
Jan 23

System size dependence of higher harmonic azimuthal anisotropy for charged hadrons via
two-particle correlations at RHIC-PHENIX, Koichi Kihara (University of Tsukuba)
Azimuthally sensitive HBT in √sNN =2.76TeV Pb-Pb collisions at LHC-ALICE, Naoto
Tanaka (University of Tsukuba)

Measurement of the sign of instability jittery magnetic moment by β-NMR with rotating
magnetic field, Naruki Inaba (University of Tsukuba)

47

8.

SYMPOSIUM
A research prospect of multi-tandem accelerator facility at University of Tsukuba –Innovation and development of new aspect by means of 6 MV tandem accelerator
18 March 2014
Laboratory of Advanced Research B 0110

1. Openning : E. Kita (University of Tsukuba)
2. Future prospects of nuclear physics experiments by 6 MV tandem accelerator at University ofTsukuba : A. Ozawa (University of Tsukuba)
3. SIMS of amino-acids by swift C60+ ion transmission : K. Nakajima (University of Kyoto)
4. PIXE analyses of trace elements in fluid inclusions from a granite and meteorites : M. Kurosawa(University of Tsukuba)
5. Towards understanding the mechanism of cluster effects on the secondary electron yield : S. Tomita(University of Tsukuba)
6. Limit of detection and application of high-resolution ERDA : D. Sekiba (University of Tsukuba)
7. Development of high sensitive palmtop sensor with etched tracks : K. Awazu (National Institute ofAdvanced Industrial Science and Technology (AIST))8. Future prospects of ion beam applications by 6 MV tandem accelerator at University of Tsukuba :K. Sasa (University of Tsukuba)
9. Closing remarks : D. Sekiba (University of Tsukuba)

48

9.

LIST OF PERSONNEL

Tandem Accelerator Complex
E. Kita

Director, Professor

K. Sasa

Associate Professor

D. Sekiba

Assistant Professor

H. KimuraComputer Engineer

H. Oshima

Electrical Engineer

Y. Tajima

Mechanical Engineer

S. Ishii

Mechanical Engineer

T. Takahashi

Electrical Engineer

Y. YamatoElectrical Engineer

S. Selvakumar

Research Fellow

M. Matsumura

Research Supporter

K. MiyaAdministrative Staff

M. Ohyama

Administrative Staff

Y. Matsuda

Administrative Staff

N. YamadaAdministrative Staff

H. Muromachi

Administrative Staff

Research Members1
Inst. of Physics
I. AraiT. Matsunaka

D. Nagae

A.Ozawa

K. Akimoto

S. Aoki

E. Kita

M. Minagawa

D. Sekiba

T. Suemasu

S. Tomita

A. Uedono

H. Yanagihara

Y. Watahiki

K. Sasa
Inst. of Applied Physics

Inst. of Materials Science
T. Kondo

M. Takahashi

1The “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.

49

Inst. of Geoscience
M. Kurosawa
Inst. of Chemistry
K. Sueki
Staff of Open Advanced Facilities Initiative
H. KudoH. Naramoto

H. Muromachi

Graduate students
Doctoral Programs of Pure and Applied Science
Y. AbeS. Fukuoka

K. Kurita

S. Kimura

Y. Ishibashi

K. ItoMaster’s Programs of Pure and Applied Science
R. Aoyama

F. Arai

K. Chito

I. Harayama

A. Horiuchi

N. Inaba

D. Izumi

Y. LiuS. Kimura

R. Kinoshita

A. Mori

J. Morishita

M. MukaiS. Okada

T. Onishi

Y. SaitoT. Sanai

Y. Satou

K. Sawahata

Y. Shiina

Y. Utsumi

T. Watanabe

K. Yamazaki

Z. Yang

Y. Yasutomi

N. Yoshihara

Undergraduates
H. Alime

A. Kamezawa

S. Maeda

T. Oguro

T. Senba

K. Watanabe

R. Watanabe

Y. Yatsu

Scientific Gutests and Fellows
K. Awazu

National Institute of Advanced Industrial Science and Technology (AIST)

M. Fujimaki

National Institute of Advanced Industrial Science and Technology (AIST)

Y. Tosaki

National Institute of Advanced Industrial Science and Technology (AIST)50

T. Hayakawa

Japan Atomic Energy Agency (JAEA)

T. Shizuma

Japan Atomic Energy Agency (JAEA)

S. KubonoCenter for Nuclear Study, the Univ. of Tokyo (CNS)

A. SatoOsaka Univ.

A. Yamamoto

High Energy Accelerator Research Organization (KEK)

T. AdachiHigh Energy Accelerator Research Organization (KEK)

M. YoshidaHigh Energy Accelerator Research Organization (KEK)

N. Kawamura

High Energy Accelerator Research Organization (KEK)K. Shimomura

High Energy Accelerator Research Organization (KEK)

P. Strasser

High Energy Accelerator Research Organization (KEK)

T. Nakamoto

High Energy Accelerator Research Organization (KEK)

M. IioHigh Energy Accelerator Research Organization (KEK)K. YoshimuraHigh Energy Accelerator Research Organization (KEK)51