CO4-1

Millimeter Wave Absorption Spectra of Ionic Liquids

ABSORPTION COEFFICIENT (cm -1)

T. Awano and T. Takahashi1
Faculty of Engineering, Tohoku Gakuin University
Research Reactor Institute, Kyoto University

1

INTRODUCTION: Ionic liquid (IL) is molten salt
at room temperature. It is interesting to compare ionicmotion in ionic liquids with those in superionic conductor.
We have observed millimeter wave absorption bands
around 6 and 8 cm-1 in AgI-superionic conductive glasses.
These bands were also observed in CuI-superionicones[1-3]. These bands seems to be due to collective motion of conductive ions because of their frequency, although how conduction ions moves in correlation is notclear.
Recently, we have observed sub-terahertz absorption
bands of ILs[4,5]. These bands seems to be due to ionicmovement because of their temperature dependence. That
is to say, the absorption disappear at low temperatures atwhich the IL is solid. However, the thermal change ofthese bands were in various way. This difference seems tobe due to the difference of their phase transition to thesolid states (crystal or glass).
In this study we have measured millimeter wave absorption spectra of 33 ILs to make clear the ionic movement from the temperature change of absorption spectra.

[Triethylsulfonium][TFSI]
295K
227K
158K

10

0

4

6
8
10
-1
WAVE NUMBER (cm )12

ABSORPTION COEFFICIENT (cm -1)

Fig. 1. Absorption increment spectra of [TES][TFSI].
The baseline is the absorption spectrum at 88 K.

EXPERIMENTS: A fixed amount of ionic liquids (Tokyo Chemical Industry Co., Ltd.) were spread into filter
paper. Transmission spectra of single and double papers
with ionic liquids were measured at room temperatureand low temperatures. Absorption spectra were obtainedby subtraction of them.
RESULTS: Three types of the spectral change occurred at temperature above melting point or glass transition temperature[5]. The absorption bands in the ILs
which are crystal in the solid state showed rapid decreaseat their melting points[4]. On the other hand, those in ILs
which are vitreous in the solid state weakened and shifted
gradually. Others showed complicated change as shownin Figs. 1 and 2.
Fig. 1 shows absorption spectra of Triethylsulfoniumbis(trifluoromethane)sulfonimide([TES][TFSI]). Figs. 1
and 2 shows increment spectra from that at 88K. At thistemperature, these ILs are solid and have only little absorption in this spectral range. At 158K, all four absorption bands decreased below the baseline.
Fig. 2 shows absorption spectra of Tributyl(2-methyloxyethyl)-phosphonium

20[Tributyl(2-methoxyethyl)-phosphonium][TFSI]
295K
227K
158K

10

0

4

6
8
10
-1
WAVE NUMBER (cm )

12

Fig.
2.
Absorption
increment
spectraof[TBMOEP][TFSI]. The baseline is the absorption spectrum at 88 K.
bis(trifluoromethane)sulfonimide([TBMOEP][TFSI]).
The 9.5 cm-1 band decreased below the baseline at 158 K.
REFERENCES:[1] T. Awano and T. Takahashi, J. Phys. Conf., 148(2009) 012040/1-4.
[2] T. Awano and T. Takahashi, J. Phys. Soc. Jpn. 79
Suppl. A (2010) 118-121.
[3] T. Awano and T. Takahashi, Proceedings of the 13th
Asian Conference on Solid State Ionics, (2012) 569-576.
[4] T. Awano and T. Takahashi, KURRI Progress Report
2014, CO4-2.
[5] T. Awano , A. Shikoda and T. Takahashi, 20th International Conference on Solid State Ionics, (2015) D2.02.

27008- 71 -

CO4-2Synthesis of Metal Nanoparticles and Nanocomposites by Gamma-ray
Irradiation Reduction Method
and a Raman spectrophotometer.

F. Hori, H. Nakanishi, A. Tokai, M. Tanaka, A. Iwase,
K. Okitsu, Y. Mizukoshi1 and M. Sakamoto2
Dept. of Mater. Sci., Osaka Prefecture University
1

Institute of Materials Research, Tohoku University
Research Reactor Institute, Kyoto University

2

INTRODUCTION: Metallic nanoparticles have somespecific properties, which are not appeared in bulk
materials such as catalytic activities, magnetic properties,
electro conductivity and light absorption. These
properties depend on its size, shape, structure, chemicalcomposition and so on. They have many possibilities toapplied for various industrial fields. Generally, manykinds of metal nanoparticles commercially aresynthesized by using chemical reaction method. Recent
years, some reports show that it is possible to fabricate
various metal nanoparticles under irradiation reduction
fields such as ultrasonic, electron beam, ion beam andgamma-ray irradiation. So far, we have reported thatsynthesis of shape and size controlled Au, Pd, Pt, Cu andthese complex nanoparticles by these reaction fields. On
the other hand, it is possible that graphene with Pt
nanocomposits have high catalytic activity and selectivity
due to their excellent properties of graphene and Pt
nanoparticles. We have developed a one-step gamma-ray
irradiation method to synthesize nanocomposites
composed of graphene and Pt nanoparticles from aqueous
solution containing graphene and Pt ions in water [1].
EXPERIMENTS: Aqueous solutions with a given
concentration of Hydrogen hexachloroplatinate (IV)hexahydrate (H2PtCl66H2O, Pt(IV)), SDS or 2-propanol.
Graphenepowder (6 - 8 nm thick x 5 µm wide) was
added into this water solution. The solution was argon
gas purged and sealed into polystyrene vessels. Afterdispersion by an ultrasonic cleaning bath, they were
irradiated at about 300 K with γ-rays from 60Co radio
active source at gamma irradiation facility in KURRI,
Kyoto University. The total dose was fixed to 10 kGy
with dose rate of 15 kGy/h. After irradiation, theproducts were separated by centrifugation, washed withwater and dried by freeze-drying. UV–vis absorption
spectra were measured and all products were observed byconventional TEM. Infrared spectra and Raman spectra(RS) of the prepared samples were collected by a
Fourier-transform infrared spectro-photometer (FT-IR)

RESULTS:
Figure 1 shows the UV/vis absorption spectra for
aqueous solutions before and after gamma-ray irradiation.
The absorption peak around 260 nm, which shows Pt
complex ions, disappears after γ-ray irradiation. Thisshows that Pt complex ions were reduced by γ-ray
induced reductive radicals such as hydrated electron (eaq-)
and hydrogen radicals. Figure 2 shows the TEM imagesof Pt and graphene solution sample including SDS and
2-propanol as an additive after γ-ray irradiation. Pt
nanoparticles homogeneously supported on graphene
were formed. The avarage size of Pt nanoparticles was
about 30 nm. On the other hand, from the results of
FT-IR and RS experiments, it was confirmed thatgraphene surface was chemically modified by the
carbonil groups formed after irradiation. Consequently,
fabricated Pt nanoparticles under γ-ray irradiation field
were supported on the surface modified graphene.

Fig. 1 UV/vis absorption spectra of aqueous solutions of

Pt and graphene before and after gamma-ray irradiation.

100 nm

100 nmFig. 2 TEM images of Pt nanoparticles supported ongraphene surface synthesized by gamma-ray irradiation.
References[1] A.Tokai, K.Okitsu, F.Hori, Y.Mizukoshi, A.Iwase, Rad.
Phys. Chem. 123, (2016) 68-72

27019- 72 -

Gamma-ray Induced Photocurrent of Field Emitter Array andCadmium Telluride-Cadmium Sulfied Photodiode

Graduate School of Engineering, Kyoto University
1
Nanoelectronics Research Institute, National Institute ofAdvanced Industrial Science and Technology
2National Institute of Technology, Kisarazu College
3
Research Reactor Institute, Kyoto University
4
Research Institute of Electronics, Shizuoka University
5
Radiation Research Center, Osaka Prefecture University
INTRODUCTION: Vacuum image sensors with the
combination of a field emitter array (FEA) and a photodiode are possible candidate as an elemental part of thecamera for observation of interior of the pressure vesselof Fukushima nuclear power plant, the 1st [1]. We havebeen investigating the deterioration of the performance of
FEA and cadmium telluride-cadmium sulfide (CdTe/CdS)
photodiode since 2014. These elements already exhibited
sufficient endurance against γ-ray irradiation up to 200
kGy. However, the tests have been done after the γ-ray
irradiation, and therefore little information on the change
in the property under γ-ray irradiation was obtained.
There exist many phenomena associated with the γ-ray
irradiation, including generation of photocurrent, which
prevent us from detecting image signal. This report describes the results of the measurements of photocurrent of
FEA and photodiode.

istics of the 60 μm-FEA. For the 40 μm-FEA, similar
behavior was observed. In this case, both emitter current
IE and gate current IG were measured individually. The
bias was given only to the emitter. Without γ-ray irradiation, both IE and IG were almost zero. With γ-ray irradiation, IE and IG showed linear increases with applied voltage. However, the IG did not meet with the IE. The reason
for this has not yet been clarified. Since the irradiation
tests were performed within a limited time of 5-10 min
for each condition, no degradation of the samples wereobserved after the irradiation. Separately performed experiments revealed that the FEA and the photodiodes had
sufficient tolerance up to 1.2 MGy.
ACKNOWLEDGMENTS: A part of this study is theresult of “Development of radiation tolerant compact
image sensor with a field emitter array”, carried out under the Center of World Intelligence Project for Nuclear
S&T and Human Resource Development by the Ministryof Education, Culture, Sports, Science and Technology ofJapan.
20
0
−20
−40
−60
−80
−100
0

2

Bias voltage (V)EXPERIMENTS: Six FEAs with different sizes including those of which side length is either 40 or 60 μm
were mounted on a single chip. Each FEA possessed afocus electrode in addition to the emitter and the gate [2].
Each FEA has the insulating layer between the emitterand the gate, and also between the gate and the focus
electrode. The chip was mounted on the 28-pin LSI
package, and was installed in a vacuum vessel. The CdTe
and CdS films were prepared by close space sublimation
technique and CVD [3]. Gamma-ray irradiation was performed at Gamma-ray Irradiation Facility, Research Reactor Institute, Kyoto University. Current-voltage (I-V)
characteristics of the FEAs and the photodiodes were
measured during irradiation of γ-ray. The irradiations
were done at 20, 30, and 40 cm from the radiation source
to check the dose rate dependence. The absorbed doses at
20 and 40 cm were 1.58 and 0.33 kGy h-1, respectively.
RESULTS: Fig. 1 shows the I-V characteristics of thephotodiode; dashed line, solid line, and dotted line show
the dark current, the current during γ-ray irradiation, andthe current with visible light at 20 cm apart from theγ-ray source. The photocurrent due to the γ-ray irradiation was almost proportional to the dose rate and as large
as 400-500 nA at the bias of -10 V under the absorbed
dose rate of 1.58 kGy h-1. Fig. 2 shows the I-V character-

2
dark
0
irradiated−2−1−4
1.58 kGy h−6with light−8−10−10 −8 −6 −4 −2Current ( A)

Y. Gotoh, H. Tsuji, M. Nagao1, T. Okamoto2, N. Sato3,
T. Masuzawa4, Y. Neo4, H. Mimura4, M. Akiyoshi5 andI. Takagi

Current ( A)

CO4-3

Fig. 1. I-V characteristics of CdTe/CdS photodiodewith and without γ-ray irradiation.

Current (nA)

20
10
0

Emitter

FEA
60m
Gate

−10

1.58 kGy h

−20
−25

0

−1

25

Emitter voltage (V)Fig. 2. I-V characteristics of FEA under γ-ray irradiation.
REFERENCES:[1] Y. Gotoh et al., 28th Int’l Vacuum Nanoelectronics
Conference, Guangzhou, China, July, 2015, p.240.
[2] M. Nagao et al., J. Vac. Sci. Technol. B 34 (2016)
02G108/1-6.
[3] T. Okamoto et al., Jpn. J. Appl. Phys. 52 (2013)
102301/1-3.

27021- 73 -

CO4-4

The Development of AMOC System for KUR Positron Beam Facility

K. Nagumo, Y. Nagai, K. Inoue, T. Toyama, Y. Shimizu,
B. Han, M. Shimodaira, A. Kinomura1, T. Yoshiie1, Q.
Xu1
Institute for Materials Research, Tohoku University,
1Research Reactor Institute, Kyoto University

INTRODUCTION: Low-energy antiparticles are becoming increasingly important for both scientific andtechnological applications. In particular, positrons offer
new ways to study a wide range of phenomena including
scattering with atoms and molecules, the Fermi surface of
metal, and defects and ultrafine precipitates in solids.
The ultrafine precipitation of Cu impurities containedin the old light water reactor pressure vessel (RPV) steels
are considered to be one of the main origins for the embrittlement of old RPV. The formation of these ultrafine
Cu precipitates is enhanced by the neutron irradiation.
This mechanism of embrittlement is one of the topicalissues for safety operation of reactors in the field of nuclear industry.
Positron annihilation spectroscopy is one of the powerful tools for detecting sensitively the vacancy type defects in metals and positron affinity precipitates such as
the ultrafine Cu precipitates in Fe. In order to investigate
the correlation between the formation of the Cu precipitates and the defect clusters induced by neutron irradiation, the technique of the positron age-momentum correlation (AMOC) using high intensity slow positron beamis required. Then, we are constructing a new positron
beam facility with high positron intensity at the Kyoto
University Research Reactor (KUR), which is the firstreactor based positron beam in Japan [1]. The first slow
positron beam was successfully obtained from B1-hole at
KUR two years ago [2]. Since then, the KUR operation
have been stopped. In this work, the AMOC system that
conforms to the measurement using KUR positron beamfacility was developed during the reactor shutdown.
EXPERIMENTS and RESULTS: AMOC is a techniquethat allows direct observation of the time dependent transitions of the positron states through simultaneous measurements of both the lifetime and the momentum distributions of annihilating electron-positron pairs. In case of
the conventional 3-gamma coincidence system that employ Na-22 for positron source, one nuclear gamma rayof 1.275MeV is used for time determination of positroncreation, and two annihilation gamma rays are used fortime determination of positron annihilation and measuring momentum distribution of electron-positron pair. In
case of the measurements using KUR positron beam, thestart signal should be acquired from pulsing trigger ofbuncher unit instead nuclear gamma ray, which can convert the continuous positron beam from the reactor into apulsed beam, as shown in Figure 1. The coincidence
module is consisted of Fast Amplifier, Timing Filter Amplifier, Constant Fraction Discriminator, Gate and Delay

Generator, and Universal Coincidence etc. Wave shapes
from a scintillation detector, a high-purity Ge detector
and the pulsing trigger will be directly recorded by thedigital oscilloscope with a trigger from the coincidence
module. Figure 2 shows a test result of 2D-AMOC spectrum for pure Fe measured by this system. The usual positron lifetime spectrum and the Doppler broadening energy spectrum are obtained by integrating with respect tothe momentum and the time, respectively. On the other
hand, the time dependent momentum distribution extracted from AMOC spectrum can give the chemical information on the positron trapping site every annihilation
times, which is important to understand the correlation
between precipitates and vacancy type defects.

Figure 1: Schematic diagram of conventional 3 gamma AMOC; The
start signal should be changed to pulsing trigger under the measurement
using KUR positron beam.

Figure 2: AMOC 2D spectrum of pure Fe.

We should develop and set up the beam bunching system which is consisted of the chopper, the pre-buncher
and the buncher, and the brightness enhancement system
which is consisted of a remoderator, some magnetic andelectrical lenses. The AMOC measurement will be performed after restarting KUR.
REFERENCES:[1] Q Xu et al, J. Phys. Conf. Ser. 505 (2014) 012030.
[2] K Sato et al, Nucl. Inst. Meth. Phys. Resear. B 342 (2015)
104.

27023

- 74 -

CO4-5

Basic Study on Radiation-induced Luminescence from Natural Mineral

H. Fujita, M. Sakamoto1and T. Saito1
Nuclear Fuel Cycle Engineering Laboratories, JAEA
Research Reactor Institute, Kyoto University

1

INTRODUCTION: It is well known that dielectricmaterials such as natural quartz exposed to ionizing radiation emit thermoluminescence (TL) and optically stimulated luminescence (OSL). OSL is a well-established tool
for measuring radiation doses in unfired sediments [1]. It
has features in common with TL which has long beenused in measuring radiation doses [2]. Both TL and OSL
dosimetry with white mineral do not need to be speciallyinstalled in advance, prior to dose estimation.
Quartz is an excellent material for use in
dosimetry, because of its almost ubiquitous availability
including an accidental place. Feldspar is an extensive
ternary family of minerals appropriate for OSL and TL
dosimetry as they display a strong luminescence and arequite common in the Earth’s formation, although it has
anomalous fading effects which decay OSL-related luminescence signals.
However, the detailed emission mechanisms
of TL and OSL from natural minerals such as natural
quartz and feldspar are not yet clear. In this study, theemission mechanisms of TL and OSL were investigatedin conjunction with various radiation-induced phenomena
after annealing treatments of quartz samples, involving
TL, OSL and electron spin resonance (ESR) measurements.
EXPERIMENTS: Two surface soil samples were collected at different places in Ibaraki. Natural quartz samples were extracted from the soils by a usual treatment of
6M hydrochloric acid (HCl), 6M sodium hydroxide(NaOH) followed by 60 min of concentrated hydrofluoric
acid (HF). The etching treatment with HF solution was atroom temperature. Further purification of the quartz
grains was performed by hand selection for the sake ofelimination of feldspar grains as low as possible under afluorescent lamp. The purified quartz samples weresieved to adjust the grain sizes ranging from 150 m to
250 m in a diameter for ESR spectrometry. The quartz
samples were annealed at 800 ºC for 24 hours in an electric furnace, to make luminescence signals strong. The
annealed quartz samples were irradiated a dose of 1 kGy
with 60Co source (0.64 kGy/h at D-30 cm) at room temperature at Kyoto University Research Reactor Institute(KURRI). The irradiated samples were stored at room

temperature for one day to eliminate afterglow emission
in a dark room. The ESR measurement was carried out
using an ESR spectrometer (Jeol Ltd., JES-TE 200) at−196 ºC. Prior to the ESR measurements, the quartz
samples were annealed for 1 min at 50 ºC intervals ranging from 150 to 300 ºC with a ceramic heater as preheat
treatment. A part of each sample from two sampling
points was kept in a dark room without preheating treatment. All preparations were carried out under dim red
light.
After the ESR measurements, all samples
were kept to measure luminescence signals in a darkroom. However, an automated TL/OSL-reader system(JREC) had been improved to heat sample at correcttemperature and then could not measure TL and OSL
signals.
In this research, there were our two chances
to do ESR experiment at the KURRI, but one of thechances was lost to measure ESR signals because the
ESR spectrometer could not be worked in last August.
RESULTS:The ESR signals of Al centers as
hole-trapped centers and Ti centers ([TiO4/H+]0,[TiO4/Li+]0 and [TiO4/Na+]0) as electron-trapped centerswere detected in the annealed quartz samples as before.
ESR signal intensity of Al centers decreased with preheating temperatures, gradually. Finally, the ESR signals
at 300 ºC of preheat were almost disappeared.
On the other hand, ESR signal intensity ofTi centers showed different tendency from the ESR intensity of Al centers. The intensity of Ti centers was constant up to 150 ºC of preheating temperature. After heating over 150 ºC, the intensity of Ti center decreased withpreheating temperatures. Finally, the ESR signals at 300ºC of preheat were almost disappeared as well as Al centers. The results agreed to our previous results. However,
the intensity tendency of Ti centers was different between
two quartz samples.
In this research, the luminescence emission
mechanism could not be identified. Therefore, further
work is necessary to identify luminescence mechanism
using ESR measurement and annealing experiment.
Moreover, the sample measured by ESR spectrometershould be used in luminescence measurement.
REFERENCES:[1] Huntley, D. J., et al., Nature 313, 105-107 (1985).
[2] Mckeever, S. W. S., Cambridge University Press,
Cambridge, 103-105 (1985).

27032- 75 -

Study of the Scientific Properties of Water and the Physiological Activation
Phenomena by Using High-Intensity Pulsed Coherent Radiation

CO4-6

S. Okuda, Y. Tanaka, T. Kojima, S. Kurahashi, Y. Kida
and T. Takahashi1
Graduate School of Engineering, Osaka Prefecture University
1
Research Reactor Institute, Kyoto University

INTRODUCTION: The coherent transition radiation(CTR) from electron bunches of a linear accelerator (linac) has continuous spectra in a submillimeter to millimeter wavelength range. It is a picosecond pulsed light andhence, has extremely high peak-intensities compared withthe other terahertz (THz) light sources. The light sources
using the CTR have been applied to absorption spectroscopy [1-4]. However, such light sources are very limited.
The light source system using the CTR from the electron
beams of the 45 MeV L-band electron linac has been
established at KURRI [5]. The CTR light source developed has been applied to absorption spectroscopy and it
is expected that any nonlinear effects might be observed.
Another important application is to the investigation of
the biological effects of the CTR; few experiment has
been performed so far.
The main purpose of the present work is the investigation of the biological effects of the high-intensity pulsed
CTR.
CHARACTERISTICS OF THE CTR: The CTR isemitted as a pulsed and polarized radiation. The micropulse structure of the CTR corresponds to that of theelectron beam from the linac. The light can produce theintense pulsed electric field and would cause some kindof excitation in a matter. The spectrum of the CTR is determined by the micropulse shape of the electron bunch
whose pulse width is usually about 10 ps in the case of an
L-band linac.
Shielding wall
SampleMirror system

Mirror system

Accelerator

Collimator

Detector

Lock-in Amp.

Light Source
Interferometer

Linac trigger
Experimental room

Linac room

Fig. 1. Schematic diagram showing the configurations
for absorption spectroscopy using the CTR

EXPERIMENTAL METHOD:
The experimental
configurations for the absorption spectroscopy are schematically shown in Fig. 1. The output CTR light from alight source chamber was transported out from the accelerator room. The spectrum of the light after passing
through the sample was measured with a Martin-Puplett
type interferometer and a liquid-He-cooled silicon bolometer. The sample was located on the light path between the interferometer and the detector. The light was
focused at a light collimator 8 mm in diameter locatedbefore the sample. The details of the methods for themeasurements are described in ref. 5.
The liquid samHolder plate
ples used in the
Incident light(quartz)
experimentsarewater,
aqueoussolutions of NaCl,
several kinds of Spacer
bacillus, cell andmicroorganism. In
Liquid sample
the irradiation experiments of theFig. 2 Schematic diagram of
CTR the sample
the sample holder for liquid
holder shown in Fig.
samples showing the behavior
2 was located justof the incident light.
before the interferometer on the light path. The thickness of the liquid sample was about 100 m, which was sandwiched with two
anhydrous quartz plates 3 mm thick.
RESULTS AND DISCUSSION: The basic propertiesof the CTR light source were investigated [6]. The light
spectrum was sufficiently stable during the measurements
within ±2-3% in a wavenumber range of 4-13 cm-1. The
range can be expanded to the lower or the higher wave
numbers by using light filters. The wavenumber resolution was 0.1 cm-1. The intensity of light was found to be
sufficiently high even if it becomes 10-6 of the initial one
after transmission through the sample due to absorption.
Some preliminary experiments to optimize the experimental conditions have been performed so far.
REFERENCES:[1] T. Takahashi et al., Rev. Sci. Instrum. 69 (1998) 3770.
[2] K. Yokoyama, Y. Miyauchi, S. Okuda, R. Kato and T.
Takahashi, Proc. 20th Int. Free-Electron Laser Conf.
(1998, Williamsburg, USA) II 17-18.
[3] S. Okuda, M. Nakamura, K. Yokoyama, R. Kato and
T. Takahashi, Nucl. Instrum. Meth. A445 (2000) 267.
[4] S. Okuda et al., Radiat. Phys. Chem. 75 (2006) 903.
[5] S. Okuda and T. Takahashi, Infrared Phys. Technol.
51 (2008) 410.
[6] S. Okuda and T. Takahashi, J. Jpn. Soc. Infrared
Science & Technology 25 (2016) 49 (in Japanese).

27036- 76 -

CO4-7

Analysis of Circularly Polarized CTR Using Babinet-Soleil Compensator

T. Takahashi
Research Reactor Institute, Kyoto University
INTRODUCTION: In recent years various types ofcoherent radiation emitted from a short bunch of
relativistic electrons have attracted a considerable
attention as a bright light source in the THz-wave andmillimeter wave regions for the spectroscopic purpose.
Coherent transition radiation (CTR), which is emitted
from a boundary between two media, is one of such a
coherent light source. CTR is usually utilized as a
non-polarized light source, because the electric vector oftransition radiation (TR) emitted from a metallic screen isaxially symmetric with respect to the trajectory of anelectron beam. In my previous reports [1] the circularly
polarized CTR using a pair of wire-grid radiators with thedifferent polarization has been developed with a new idea.
Shibata et al. has developed a technique of generation of
circularly polarized millimeter-wave radiation with thephase difference between the forward TR and the
backward one [2]. However, it was difficult to control thepolarization degree in that technique. The significant
point of my new technique is the use of linearly polarized
CTR with the wire-grid radiator. With this technique thepolarization degree is able to be controlled precisely. In
this report circularly polarized CTR has been analyzed
using a hand-made Babinet-soleil compensator.
Circularly polarized light has been useful in the circulardichroism spectroscopy.
EXPERIMENTAL PROCEDURES: The experiment
was performed at the coherent radiation beamline [3] atthe L-band linac of the Research Reactor Institute, Kyoto
University. The energy, the width of the macro pulse, andthe repetition rate of the electron beam were 42 MeV, 33
ns, and 20 Hz, respectively. The average current of theelectron beam was 0.5 A. The schematic diagram
around the radiation source of this experiment is shownin Fig.1. Two wire-grid polarizers (WG1 and WG2) 10
m thick with 25 m spacing were used in order togenerate the CTR with horizontal and verticalcomponents, respectively. Each CTR was superposedwith phase difference through the optical delay system.
Although a Martin-Puplett-type interferometer is usuallyused as a spectrometer, a grating-type monochromator
was used in this experiment. The monochromator was set
for the wavelength of 2.3 mm. The CTR was detected bya liquid-helium-cooled Si bolometer. In order to measure
the polarization diagram a wire-grid polarizer with arotary holder and a Babinet-soleil compensator were usedin front of the detector.
RESULTS: The observed polarization diagrams ofcircularly polarized CTR at the phase difference of /2
and 3/2 are shown in the left figures in Figs.1 and 2,
respectively. In order to analyze the circular polarization
the thickness of the Babinet-soleil compensator was set
as a quarter-wave retarder. The observed light through thecompensator has not perfect linear polarization as shownin the right figures in Figs.1 and 2. These results havebeen attributed to the lack of coherence of CTR becauseof the large size of the electron beam.
REFERENCES:[1] T. Takahashi, et al., KURRI-PR 2014 CO4-15.
[2] Y. Shibata et al., Rev. Sci. Instrum. 72 (2001) 3221.
[3] T. Takahashi et al., Rev. Sci. Instrum. 69 (1998)
3770.

27073

- 77 -

Fig.1. The schematic diagram of the experiment.

Fig.2. Circularly polarized CTR at the phasedifference /2 (left) and polarization diagram
through the compensator (right).

Fig.3. Circularly polarized CTR at the phasedifference 3/2 (left) and polarization diagram
through the compensator (right).

CO4-857

Fe Mössbauer Spectra of Normalconducting Sr2CrFeAsO3-d

T. Otsuka, H. Fujioka, M. Matoba, S. Kitao1, M. Seto1
and Y. Kamihara
Department of Applied Physics and Physico-Informatics,
Keio University
1
Research Reactor Institute, Kyoto University

the existence of spin density wave phase are observed for
x = 0.18, while antiferromagnetic ordered Fe are observed for x = 0.03. The result indicates that
normalconducting Sr2CrFeAsO3-d shows two magnetic
ground states, which stabilities depend on oxygen deficiency.

INTRODUCTION:
Layeredoxypnictide
Ae2TMFePnO3-d (Ae = Alkaline earth metal, TM = Transition metal) (21113) consists of carrier conducting FePn
(Pn = P and As) layer and carrier blocking Ae2TMO3 layer.
Several 21113 shows superconducting phase at low temperatures. Hyperfine fields (Bhf) measurements experienced by nuclei of atoms at crystallographic sites inmagnetic and/or antiferromagnetic metals are of interestin view point of hyperfine interactions and important for
their use in the determinations of nuclear magnetic dipole
moments by a variety of methods including those basedon low-temperature nuclear orientation. Guang-Han Cao
et al reported that Sr2VFeAsO3-d is an FeAs-based layered
oxypnictide superconductor, which reveals antiferromagnetic under 150 K originating in local d-electron
moments of vanadium, and the superconducting transition temperature Tc is 24 K.[1] In this study, we focus onmagnetic phase of Sr2CrFeAsO3-d as a possible mothercompound of iron-based superconductors. [1-5]Element-specific magnetism and electronic phase of Fe
sublattice in Sr2CrFeAsO3-d are elucidated using 57Fe
Mössbauer spectroscopy. Studies on hyperfine fields Bhf
experienced by nuclei of impurity phases are of interestin view point of hyperfine interactions and important for
their use in the determinations of nuclear magnetic dipole
moments by a variety of methods including those basedon low-temperature nuclear orientation.
EXPERIMENTS:
Polycrystalline
samplesof
Sr2CrFeAsO3-d were prepared by the solid-state reactions
in a sealed silica tube using dehydrated SrO, FeAs, Cr2O3,
Cr as starting materials. Then, a mixture of the threepowders was pressed into pellet and heated in doubly
sealed silica tubes at 1030~1330 °C for 40 h. All procedures were carried out in an Ar-filled glove box (MIWA
Mfg; O2, H2O < 1 ppm). The crystal phase of the obtained product was examined by powder X-ray diffraction (XRD; RigakuRINT-2500) using CuK radiation.
Almost all the diffraction peaks are assigned to theSr2CrFeAsO3-d phase. Electrical resistivity measurements
were performed at 2–300 K by a dc four-probe techniqueusing silver paste as electrodes. Magnetization measurements were performed for polycrystalline samples using a
Quantum Design magnetic properties measurement system (MPMS). The 57Fe Mössbauer (MS) experiment on
the two series of compounds, Sr2CrFeAsO3-d (x = 0.03,
0.18) was performed with conventional 57Fe MS equipment using 14.4 keV -rays from a 57Co source in an Rh
matrix.
RESULTS: 57Fe MS to the samples of d=0.03, 0.18 of
Sr2CrFeAsO3-d were measured and analyzed for obtaining
quantitative value of internal magnetic field. As a result,Fig. 1. 57Fe Mössbauer spectra (MS) of polycrystalline Sr2CrFeAsO3-d (d = 0.03 and 0.18) at several
temperatures described in the figure. The solid lines
for d = 0.03 are fitted patterns provided that a internal magnetic field. The solid lines for d = 0.18 are
fitted patterns provided that a wide distribution ofinternal magnetic field. Profiles of FeAs, which aredenoted by Green lines, are reproduced fromBlachowski et al’s results. [6,7]
REFERENCES:[1] G. H. Cao et al., Phys. Rev. B 82, 104518 (2010).
[1] Y. Kamihara et al., New J. Phys. 12, 033005 (2010).
[2] D. Johrendt et al., Physica C, 469, 9 (2009).
[3] X. Zhu et al., Phys. Rev. B 79, 220512 (2009).
[4] M. Tegel et al., Z. Anorg. Allg. Chem. 635, 2242
(2009).
[5] X. Zhu et al., Sci. China Ser. G 52, 1876 (2009).
[6] A. Blachowski et al., J. Alloy. Compd. 582, 167(2014).
[7] A. Blachowski et al., Phys. Rev. B 83, 134410 (2011).

27074- 78 -

CO4-9Complex Structure of Ions Coordinated with Hydrophilic Polymer. 16.
Application for Metaric Plating on Resin Surface. (1)A. Kawaguchi and Y. Morimoto
Research Reactor Institute, Kyoto University
INTRODUCTION: We have reported interacted structures between iodine (polyiodide ions, Inm-, m, n: integer,n ≠ 1 ) and polymers.[1] While polyiodide ions ( andtheir counter-ions ) are prepared as solutes in aqueous
solution, they can be diffused into various polymeric matrix. Such structures and procedures are expected to
introduce novel functionality and wide applications topolymeric materials with easy operation.[2]For some hydrophilic polymers, diffusion of iodine from
aqueous solutions advances very quickly and, in somematrix such as polyamide-6 (PA6), ionic diffusion into
crystallite region or "diffusion-induced" orientation are
also observed through easy operation at room temperature; as phenomena, iodine-doped polymers can be regarded as "pseudo solvents" for ionic diffusion.[3,4]These results suggest that coordination between iodine
and polymers is dynamic and pliable and activated process and that previous existence of polyiodide ion drastically enhances posterior ionic diffusion in polymers.
On the other hand, self-organization and diffusion keeping ordered structure are also observed; processes looked
opposite or paradoxical go simultaneously as both ordering and disordering effects. Furthermore, such ionicbehavior can be qualitatively applicable for hydrophobic
matrix even if sample operation are wholly carried out
with aqueous solution of polyiodide ions.[5]Some advantages can be suggested as availability forsuch operation using polyiodide ions: maintenance of
shape or convenience of size of matrix, deep and gradientinjection of inorganic components in spite of operationeven at room temperature, preparation with aqueous solutions,,, etc. Previously, we reported “(1st) iodine doping” and “secondary doping” of Ag+ ion into hydrophobic
materials with aqueous solutions.[6] Here, injection of
metallic ions or inorganic salts into polymeric matrix are
expected to apply electroless plating resin surface.
EXPERIMENTS: As hydrophobic materials as matrix,
silicone-rubber tube (LABORAN, φ2x4 ), PE (polyethylene) tube and PP (polypropylene) film were treated.
These matrixes were “iodine doped” by immersing in I2KI(aq) or I2-NH4I(aq) (3.0N) for more than one week. For
secondary doping of Ag+ ion, each samples were
immersed in AgNO3(aq) (2.0M) solution for a few days.
On electroless plating of Cu in aqueous solution, THRUCUP PSY (UYEMURA) was used. All opera-tion weredone at room temperature (c.a. 25℃).

hydrophobic as chemical composition. Actually, affinity with each aqueous solutions was not so activated ineach process without “iodine doping”. And, even applying “iodine doping”, increase in mass (m) in each
preparation steps were tiny (less than 1-2%) and coloredappearance on “(1st) iodine doping” was negligibly slightwhile, to hydrophilic matrixes, m = 50-200% (or more)or solid and tough “black” coloring were frequently observed for “iodine doping”.[1] However, as results after
electroless Cu plating process to the hydrophobic matrixes, deposition of Cu was observed on surface of eachhydrophobic matrixes.(Figure)
Such Cu deposition is regarded as process at restrictedsurface region of each matrixes. In the cases of hydrophobic matrixes, diffusion of polyiodide ions might bequalitatively very slight and following ionic diffusion
introduced posteriorly is also negligible; ionic diffusionand exchange (ex. polyiodide ions, counter ions, “secondarily doped” ions,,,) are hardly explicit like as hydrophilic systems. Nevertheless, results showing activatedaffinity with aqueous solutions means that “iodine doping” can suggest potential abundance for functionality tounexpectedmatrixes.
REFERENCES:[1] A. Kawaguchi,
Polymer, 35,
3797-3798. (1994)[2] patent. JPN-5444559 (2014).
[3] KAWAGUCHI
Akio, et.al., SPring-8
User Exp. Rep. 5(2000A), 354-354.
(2000)[4] A. Kawaguchi,
Polym. Prep. Jpn.,

62, 5116-5117.
(2013)[5] A. Kawaguchi,
Polym. Prep. Jpn.,

64, (3H07) (2015)[6] Y. Gotoh, et.al.,
Polym. Prep. Jpn., 51,
2259-2259. (2002)

RESULTS: Intrinsically, the treated three matrixes are

27075- 79 -

Figure: Electoless plating for hydrophobic matrixes
treated with aqueous solutions for all process after
applying polyiodide: silicone rubber tube (top), PE
tube (center), PP film (bottom).

Interactions of Deuterium with Defects Created in Tungsten by
Irradiation of High Energy Electrons

INTRODUCTION: Retention of hydrogen isotopes especially tritium in plasma facing materials is one of theimportant issues in safety assessment of fusion reactors.
Recent report shows that neutron irradiation significantly
increases deuterium (D) retention in W, a leading candidate of plasma-facing material, due to trapping effects ofradiation-induced defects [1]. However, detailed trapping
mechanisms have not been clarified. For better understanding of defect-hydrogen isotope interactions, in thisstudy, W specimens were irradiated with high energy
electrons to induce Frenkel pairs uniformly throughout
the bulk, and clustering of vacancy-type defects and Dtrapping were examined using positron annihilation spectroscopy (PAS) and thermal desorption spectroscopy(TDS).
EXPERIMENTS: Disks of recrystallized W (RC-W)
and stress-relieved W (SR-W) were irradiated with
8.5 MeV electrons at around 373 K to 10-3 dpa. Then
those specimens were subjected to exposure to D2 gas(0.1 MPa) or annealing in vacuum at 573 K for 100 h.
Size distributions of vacancy-type defects were examinedusing PAS, and D retention was measured using TDS.
RESULTS AND DISCUSSION: The results of positron lifetime measurements for RC-W are summarized inTable 1. The positron lifetime before the irradiation was
118 ps. It clearly increased to 170 ps by the electron irradiation due to formation of dislocations, mono- and/or
divacancies. Long lifetime components appeared after D2
gas exposure and annealing in vacuum at 573 K, and thepositron lifetime after D2 gas exposure (~280 ps) was
significantly shorter than that after annealing in vacuum(~342 ps). The increase in positron lifetime showed theclustering of vacancies. The difference between D2 gas
exposure and annealing in vacuum can be explained byretardation of clustering of vacancies by D in W and/or
decrease in the effective open-volume in vacancy clusters
due to D trapping. Similar change in the lifetime wasobserved also for SR-W. Coincidence Doppler broadening spectroscopy showed that the correlations between S
and W parameters for the specimens before irradiation,
after irradiation and after annealing in vacuum fell on asingle straight line in S-W plot, while the specimen exposed to D2 gas after the electron irradiation showed theTable 1 Positron lifetime in W under as-prepared conditions (non-irr.), after electron irradiation at ~373 K to10−3 dpa (e-irr.) and subsequent annealing at 573 K for
100 h in vacuum (e-irr. vac. anneal.) and in 0.1 MPa D2 gas(e-irr. D2 exp.).
SampleAverage
Positronlife time(ps)

Short life
componentLong life
component

1.8
2

Hydrogen Isotope Research Center, Organization for
Promotion of Research, University of Toyama
1
Graduate School of Science and Engineering for Education, University of Toyama
2Institute for Materials Research, Tohoku University
3
Graduate School of Science and Engineering, Kagoshima University,
4
Research Reactor Institute, Kyoto University

clear deviation from the line. These observations aregood evidences for that D was trapped at vacancy clusters.
TDS showed significant increase in D retention due to theirradiation, as shown in Fig. 2; D concentration in RC-W
increased from [D]/[W] = 1.1×10-6 to [D]/[W] = 8.6×10-6.
A desorption peak appeared at 850 K and a shoulder wasobserved at 975 K. These two desorption stages appeared
to correspond to the detrapping of D from small and large
vacancy clusters observed using PAS. The evaluation
using a diffusion analysis program showed that thesedesorption temperatures correspond to the activation energy for detrapping of 1.55 and 1.85 eV. Interestingly, D
retention in the irradiated SR-W was larger than that in
the irradiated RC-W and it was [D]/[W] = 5.5×10-5.

17

Y. Hatano, K. Ami1, T. Toyama2, K. Sato3 and Q. Xu4

Desorption flux (10 D/m s)

CO4-10non-irr.

e-irr.

e-irr.
vac.
anneal.

e-irr.
D2 exp.

118

170

231

194

-

-

130

134

-

-

342

280

Recrystallized W

1.6 After exposed to D gas at 0.1 MPa
2
1.4 and 573 K for 100 h
1.2

e-irradiated

1.0
0.8
0.6

non-irradiated

0.4
0.2
0.0
300

500

700

900

Temperature (K)

1100

1300

Fig. 2 Thermal desorption spectra of D from the recrystallized W specimen under as-prepared conditions andthat irradiated with 8.5 MeV electrons to 10−3 dpa.
REFERENCES:[1] Y. Hatano et al., J. Nucl. Mater., 438 (2013)
S114–S119 and Nucl. Fusion 53 (2013) 07300

27082- 80 -

CO4-11 Effect of Ion Species on Defect Formation near Surface of GaSb by Ion Irradiaiton
C. Watanabe, N. Nitta, M. Taniwaki, A. Kinomura1
and T. Yoshiie1
School of Environmental Science and Engineering,
Kochi University of Technology
1
Research Reactor Institute, Kyoto University

INTRODUCTION: Porous structure is formed on
GaSb surface by ion beam irradiation [1], [2]. It was clarified that the structure is formed by migration of point
defects induced by ion irradiation. The first the voids
form from the oversaturated vacancies and they develop
by movement of vacancies and interstitials. However, thethe detailed process of void formation has not yet been
understood. In this study, the effect of various ion species
on GaSb void formation by ion irradiation was investigated. The ion species used in this work are ions of carbon group elements, by which it will be possible to detect
only the effect of ion mass except the chemical effect.
EXPERIMENTS: GaSb (001) wafers were irradiatedat about 100 K by C, Si, Ge, Sn, Pb using a heavy ion
accelerator at Research Reactor Institute, Kyoto University. The acceleration voltage was 60 kV. The ion dosewas 2.80×1019 ions/m2 for C, 1.57×1019 ions/m2 for Si,
1.01×1019 ions/m2 for Ge, 6.02×1018 ions/m2 for Sn, and7.05×1018 ions/m2 for Pb. These ion doses were determined to gives a same peak concentration in depth profile
of vacancy concentration in GaSb calculated by SRIM
code simulation [3], adopting the displacement thresholdenergy values obtained by Thommen (6.2 eV for Ga and7.5 eV for Sb) [4]. The surface morphology was observed
by a FE-SEM (field emission scanning electron microscope, JEOL JSM-7401F).
RESULTS AND DISCUSSION: The voids were observed on the surfaces irradiated by relatively large massions (Ge, Sn, and Pb), and they were scarcely formed on
the surfaces irradiated by the small mass ions (C and Si).
Figure 1 shows distributions of vacancy created by one
ion irradiation obtained by SRIM code simulation. The
distribution of point defects in depth direction is muchdifferent between ion species. In the case of light ions,vacancies are formed in deep region from the surface andthe local vacancy concentration is low. In the case ofheavy ion, the vacancies are created in shallow region
and its local concentration is high, when they aggregate
easily and lead to void formation. In contrast, vacancies
created at low concentration in wider region diffuse sothat void formation scarcely occurs. This is the explanation that the surface structures were different between
heavy ion irradiation (Ge, Sn and Pb) and light ion irradiation (C and Si).

27084

- 81-

Fig. 1. Vacancy distributions of one ion irradiation
obtained by SRIM code simulation.

REFERENCES:[1] D. Kleitman and H. J. Yearian, Phys. Rev. 108 (1957)
901.
[2] N. Nitta, M. Taniwaki, Y. Hayashi and T. Yoshiie, J.
Appl. Phys., 92 (2002), 1799-1802.
[3] J. P. Biersack and L. G. Haggmark, Nucl. Instrum.
Methods 174, (1980) 257; J. Ziegler, Software and web
site, http://www.SRIM.org.
[4] D. Thommen, Phys. Rev. 174, (1968) 938.

CO4-12

Electron Beam Test of Avaranche Photodiode for Ganymede Laser
Altimeter of Jovian Icy Satellite Exploerer

M. Kobayashi, O. Okudaira, K. Ishibashi, M. Fujii1, T.
Takahashi2 and N. Abe2
Planetary Exploration Research Center, Chiba Instituteof Technology
1
FAM science2
Research Reactor Institute, Kyoto University

INTRODUCTION: The Ganymede Laser Altimeter(GALA) as part of the JUICE (Jovian Icy Satellite Explorer) payload is one of the instruments focusing on aspects related to the presence and characterizations ofsubsurface water oceans [1] [2]. For the first time thetime-variability of the global figure of a moon due totides exerted by Jupiter will be detected by altimetry
measurements.
Laser pulses are emitted at a wavelength of 1064 nm
by using a Q-switched Nd:Yag laser at operational frequencies of 30 and 75 Hz, respectively. The pulse energy
and pulse repetition frequency depend on the different
JUICE mission phases. The beam is reflected from thesurface (surface spot size is about 50 m) and received
around 3 ms (assuming the 500 km orbit) later at a 25 cm
diameter F/1 telescope. The returning laser pulse is refocused onto a silicon avalanche photodiode (or APD)
through a narrow bandpass interference filter. The signal
is then sampled and fed to a digital range finder. Thissystem determines the time of flight (and therefore range),
the integrated pulse intensity, its width and full shape.
The data are passed to a digital processing unit which
controls the operation and services the spacecraft interface. GALA will provide <1 ns time resolution (<15 cm
range, <8 cm under optimal conditions).
APD for GALA: We adopted an APD product manufactured by Excelitas Technologies, Montreal in Canada.
They commercially manufacture APD product particularly a hybrid module of APD which contains an APD
sensor, a preamplifier, a thermo-electric controller and atemperature sensor in a package. Their APD product thatare customized for space use have been adopted for space
missions due to its compactness and heritage in space.
The APD has also sensitivity to radiation that induceshole-electron pair in the depression layer. In space environment, the induced signal may affect light detection as
background noise, called radiation noise. Jupiter has astrong magnetosphere and previous studies revealed energetic electrons are trapped in the magnetosphere andmajor component among the other ionizing radiation like
proton and the other energetic ion. The APD will beshielded up against to the Jovian radiation environment
however some of electrons can penetrate the shield into
the APD. In this study, we used KURRI-LINAC as anelectron beam source to emulate electrons irradiating the
APD to investigate how energetic electron induces signals and interferes the returning laser pulse signal.
EXPERIMENTS: We used an APD product of C30954E,

Excelitas Technologies, which is the same product as one
for GALA. The APD sensor has a diameter of 0.8 mm
and an enhanced sensitivity in infrared range, about 0.4
of quantum efficiency at 1064 nm. It does not include any
preamplifier so a preamplifier was prepared and externally attached to the device. The amplifier is atrans-impedance amplifier, the same as one for GALA
flight APD. Although the band width for GALA APD had
not been decided yet, 100 MHz was adopted as plausible
number for the GALA APD.
In an irradiation test, 5 MeV electron were irradiatedto the APD. During irradiation, reverse bias high voltage
was applied to the APD sensor and the ground line was
fed to the following preamplifier. The output signals of
the amplifier were monitored and recorded with a digital
oscilloscope.
RESULTS: As shown in Fig. 1, clear pulse signals
were detected and they correspond to vertical hits of single electron on the APD sensor. In actual environment,
energetic electron with various energies omni-directionaly comes and penetrates the sensor. And also
the APD sensor will be sit in the radiation shield where
secondary radiation are induced affecting the optical returning pulses. Those will be investigated in further experiments.

Fig.1. An example of output signal pulse from the
APD.
REFERENCES:[1] H. Hussman et al., EPSC Abstracts, vol. 8,
EPSC2013-428, 2013.
[2] H. Hussman et al., EPSC Abstracts, vol. 9,
EPSC2014-347, 201427085
- 82 -