12. Others

概要

CO12-1 Survey on Radioactive Cesium Migration between Environment and Body of Wild
Boar (Sus scrofa) Living in Fukushima Prefecture
muscles and stomach contents for 20 wild boars showed
0.05, and it meant there is no relationship between them
caught in 2021 and 2022.
Long irradiation was done for 25 different
muscle samples and obtained 5 levels of elements.
Their averages and standard deviations are shown is
shown in Table 1.

M. Fukushima1, Y. Tsuji1, Y. Iinuma2, H. Komatsu3, R.
Kumada3, K. Kanda3
Graduate School of Science, Kyoto University
1
Faculty of Science and Engineering, Ishinomaki Senshu
University
2
Institute for Integrated Radiation and Nuclear Science,
Kyoto University

Table 1. Elemental levels in wild boar muscles.
(unit: mg/kg, dry weight)

Fukushima Prefectual Centre for Environmental Creation
3

Se

INTRODUCTION: Migration of radioactive cesium
caused by Fukushima-Daiichi Reactor accident between
environment and several species of wild animals in 2011
has been studied by several groups including Fukushima
Prefecture Centre for Environmental Creation. In their
results, radioactive cesium levels showed correation between wild boar muscle and stomach contents[1], and it
suggested that radioactive cesuim migrate from diets to
wild animal bodies. Wild boar diets show seasonal
changes, and it is expected that trace elements levels in
wild animals show seasonal changes. For these purposes, we have analyzed several elements in muscles and
gastrointestinal contents including stomach, colon, and
rectum of wild boars living in Fukushima Pref.
EXPERIMENTS: Wild boars were trapped in Nihonmatsu City, Fukushima Pref. under the permission of Fukushima Pref. from May 2018 to February 2022. After
euthanasia by neck shot, musclus quadriceps, contents of
the stomach, colon, rectum, and the liver were removed
from body, freeze-dried, pulverized, and gamma-ray
counting was done for Cs-134 and Cs-137 radioactivity.
Also, before freeze-drying, some amount of stomach
content was kept in 70% ethanol soln. and separated each
materials unter optical microscope for estimating wild
boar diet. One portion of dried power was supplied for
short irradiation and another portion was used for long
irradiation in KUR. Eight elements of Ca, Cl, Cu, K,
Mg, Mn, Na, and V were analyzed by the condition of 1.5
min TcPn irradiation, 3 min cooling time, and 10 min
gannma counting using germanium detector with Compton suppression system, also eight elements of Co, Cr, Cs,
Fe, Rb, Sc, Se, and Zn were irradiated for 1 hour and
gamma counting was done for 20 - 30 min after 1 month
cooling time. For different standard reference materials
were used: NIST SRM 1575 Pine Needles, NIST SRM
1577b Bovine Liver, NIST SRM 1573a Tomato Leaves,
and NIST SRM 1515 Apple Leaves.

Cr

Rb

Fe

Zn

Avg

0.95

0.86

21.2

92.9

109

SD

0.39

0.73

16.4

22.0

38

Long irradiation was done
for 3 different gastrointestinal contents and obtained 7
elemental levels, and their averages and standard deviations are shown in Table 2.
Table 2. Elemental levels in gastrointestinal contents.
(unit: mg/kg, dry weight)
Element
Sc*1
Cc*2

Se

Cr

Sc

Rb

Fe

Zn

Co

Avg

1.97

6.23

1.34

4.23

4190

30.5

1.06

SD

2.34

6.01

0.05

7.32

260

5.9

0.16

Avg

3.78

16.5

5.53

36.9

16300

67.6

4.94

SD

4.55

5.1

0.49

8.1

800

29.3

0.56

Sc*1: stomach content, Cc*2: colon content.

When gamma spectra were measured, high levels of
photopeaks caused from Sb-124 were found, and the
highest peak energy of Sb-124 is 602.7 keV, which almost overlaps with photopeak of 604 keV caused from
Cs-134. Sb and high levels of Fe are supposed to be the
content of soil ingested with diets such as potatos, fallen
acorns, insects, and so on. For investigating the migration of radioactive Cs, equilibrium of stable Cs and radioactive Cs in both environment and diet, it is important to
analyze stable Cs both in the body of wild boars and in
environment. Since stable Cs changes to Cs-134 by
neutron irradiation, separation of soil and diet in stomach
contents is needed.
REFERENCES:
[1] Y. Nemoto et al., Journal of Environmental Radioactivity, 225 (2020) 106342.

RESULTS: Stomach contents were
mainly consisted by leaves, stem, and fleshy fruits for
whole study periods. Roots was main diet in autumn
and winter, likely due to poor fruiting of acorns, which is
known as main diet of the wild boar in these seasons.
content> Correation factor (R2) of Cs-137 levels between

R4003
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CO12-2 Synthesis of high-quality crystals for laser shock experiments:
Implicartions for understanding the giant planet interiors
Y. Umeda1, Y. Seto2, T. Sekine3, T. Duffy4, F. Coppari5, R.
Smith5, and T. Okuchi1

gas-mixing furnace (Fig. 1).
Recovered ferropericlase plate

Institute for Integrated Radiation and Nuclear Science,
Kyoto University
2
Graduate School of Science, Osaka Metropolitan University
3
Center for High Pressure Science & Technology Advanced Research
4
Department of Geosciences, Princeton University
5
Lawrence Livermore National Laboratory

1

EXPERIMENTS: The (100) single crystal periclase
MgO plate (5 x 5 x 0.05~0.15 mm), MgO powder, and
FeO powder were prepared as starting materials. At first,
mixed powder in fixed FeO and MgO ratios were
grounded using an agate mortar and pestle. Mixing ratio
was FeO:MgO=0.11: 0.89. Pellets were made of mixed
powder using pelletizer at 2 MPa. The pellets of the
mixed powder were baked for 18 h at 1400oC and
CO2=340 cc/min, H2=80 cc/min (logfO2=-7.5) in a
gas-mixing furnace at Kobe university using H2/CO2
gases, keeping O2 fugacity between iron-wustite (IW)
and quartz-fayalite-magnetite (QFM) buffer.
In next, the MgO plates were packed by
pre-synthesized (Fe0.11, Mg0.89)O powder using pelletizer.
Packed pellets were backed for 30 hours at 1450oC and
CO2=340 cc/min, H2=80 cc/min using H2/CO2 gases,
keeping O2 fugacity between IW and QFM buffer. After
that, we excavated the crystal and polish it for X-ray diffraction (XRD) and Scanning electron microscopy (SEM)
analyses to evaluate homogeneity and chemical compositions.
RESULTS: Single crystal ferropericlase has been synthesized via the interdiffusion of Mg-Fe between MgO
plates and pre-synthesized (Mg, Fe)O powder in a

Scanning electron microscopy (SEM) imaging and
energy dispersive X-ray (EDX) compositional analyses
were performed across the short dimension of the single
crystals and show that the samples are free of porosity
and chemically homogenous Mg/(Mg+Fe) composition 92.9
± 0.2 (Fig. 2).

Fig. 2. SEM image of a ~100 μm thick (Mg,Fe)O
single crystal synthesized in this study. Five EDX
analyses were performed across the short dimension
of the single crystal.
150000
Signal counts (arb. unit)

INTRODUCTION: The properties of ferropericlase,
(Mg, Fe)O, especially its phase transition from the B1
(NaCl) to the B2 (CsCl) -type structure, may play a key
role in controlling the deep dynamics of many rocky exoplanets, influencing properties such as mantle viscosity,
heat flow, and magnetic field generation1,2. However,
shock wave experiments to date have focused almost
exclusively on the MgO or FeO endmembers. There are
very limited shock compression data on planetary-relevant intermediate (Mg, Fe)O compositions.
In this study, we synthesized the single crystal of ferropericlase with high purity and chemical uniformity to
understand the interiors of giant planets with a more reasonable chemical composition. This project will provide
the first experimental data for directly testing recent theoretical predictions of metallization and phase stability of
this material under conditions of super-Earth interiors and
provide insights into the kinetics of polymorphic phase
transitions under shock compression.

Fig. 1. Photo of single crystal ferropericlase synthesized for this study.

500 μm

(200)
100000

50000

(111)

(220)

0
30

40
50
60
Scattering angle, 2θ (deg.)

70

Fig. 3. Synthesized single crystal Ferropericlase,
(Mg, Fe)O. X-ray diffraction profile of the synthesized crystal by micro focus XRD.
In summary, we succeeded in synthesizing the target
composition (Mg90, Fe10)O of single crystal ferropericlase.
The establishment of synthesis in this study is expected to
enable us to obtain high-precision data for a wider range
of compositions as laser shock targets.
REFERENCES:
[1] F. Coppari et al., Nat. Geosci., 14 (2021) 121–126.
[2] S. Ritterbex et al., Icarus, 305, (2018) 350–357.

R4019
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CO12-3 Neutron Activation Analysis of High Purity Material
T. Miura1, S. Sekimoto2, R. Okumura2, H. Yoshinaga2, Y.
Iinuma2
AIST, National Metrology Institute of Japan
Institute for Integrated Radiation and Nuclear Science,
Kyoto University
1
2

INTRODUCTION: National Metrology Institute of
Japan (NMIJ) is responsible for developing certified reference materials and for establishing the traceability of SI
(The International System of Units) on chemical metrology in Japan. To establish SI traceability, the primary
method of measurements should be applied to the characterization of the certified reference materials. Neutron
activation analysis using comparator standard is recognized as a potential primary ratio method [1]. Despite the
potential of neutron activation analysis as primary ratio
method, the evaluation the measurement capability and
the measurement uncertainty are required in any analysis.
In general, there are three main components of uncertainty in neutron activation analysis, that is, sample preparation uncertainty, neutron flux homogeneity, and gamma ray measurement uncertainty. Usually, flux monitor is
used to correct the neutron flux heterogeneity. However,
although the flux monitor can correct the neutron flux
variation using the count rate of the known amount of the
monitor nuclide, it does not reflect the neutron flux of the
actual sample. ...