CO12-1

Precise Determination of Br in ABS Resin by
Instrumental Neutron Activation Analysis

T. Miura1, R. Okumura2, Y. Iinuma2, S. Sekimoto2, K.
Takamiya212National Metrology Institute of Japan, AIST
Research Reactor Institute, Kyoto University

INTRODUCTION: National Metrology Institute of Japan is responsible for developing certified reference materials (CRMs) and for establishing the traceability of SI(The International System of Units) on chemical metrology in Japan. To establish SI traceability, the primarymethod of measurements should be applied to the characterization of the CRMs. Recently, neutron activation
analysis (NAA) using comparator standard is recognized
as a potential primary ratio method [1]. Despite thepotential of NAA as primary ratio method, the evaluationof the measurement uncertainty is required in any analysis. In general, there are three main components of uncertainty in NAA, that is, sample preparation uncertainty,
neutron flux homogeneity, and gamma ray measurement
uncertainty. Usually, flux monitor is used to correct theneutron flux in-homogeneity. However, although theflux 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. The most practical method to eliminate neutron
flux in-homogeneity and to improve gamma ray measurement uncertainty is an internal standard method [2].
In this paper, we presented that notable capability of internal standardization in NAA for determination of Br inacrylonitrile butadiene styrene copolymer (ABS) resin
as a candidate CRM.

One hundred mg of the ABS resin samples was used for
Br analysis. The Au solution was added to the samples
before neutron irradiation. The neutron irradiations
were performed by KUR (Kyoto University Research
Reactor) TCPn (thermal neutron flux: 8.0 x 1010 cm-2s-1)
for 6 h. The γ ray measurement system consisted of a
Canberra GC4070-7500 Ge detector and a Laboratory
Equipment Corporation MCA600.
RESULTS: It was found that the 198Au sensitivity(cps/µg) varied according to the sample position in theirradiation capsule. The relative standard deviation of the
198
Au sensitivity (cps/µg) was 3.8 %. The uncertainty
related to the neutron flux homogeneity significantly
contributes to the overall uncertainty, if an internal standard is not applied. The amount of Br in the ABS resin
sample was determined by calibration curve method using internal standardization. The linearity of calibration
curve was improved by internal standard. The relative
standard uncertainty related to the calibration curve linearity was improved to 0.36 % to 0.87 %. The analyticalresults of Br in BCR-681 certified reference material ofpolyethylene resin by proposed method were in excellent
agreement with the certified value only using internal
standard.
The analytical results of Br in ABS resin sample byproposed method was 575 mg/kg±8.0 mg/kg (n=8). The
relative expanded uncertainty (k=2) was 1.4 %.

EXPERIMENTS: The ABS resin candidate CRM wasproduced by a mixing machine. The calibration solution of Br was prepared from NMIJ primary standard
solutions. The Au solution for the internal standard for
Br was prepared from a high purity metal. The calibration solutions contained Br and Au as internal standard.
REFERENCES:[1] R.Greenberg, P. Bode, E. De Nardi Fernandes,
Spectrochim. Acta B, 66 (2011) 193-241.
[2] T. Miura, K.Chiba, T. Kuroiwa, T. Narukawa, A.Hioki,
H. Matsue, Talanta, 82 (2010) 1143-1148.

採択課題番号 26008 内標準法を併用した中性子放射化分析法の高精度化に関する研究 通常採択
共同通常
（産総研・計測標準）三浦勉（京大・原子炉）関本俊、奥村良、飯沼勇人、高宮幸一

143CO12-2

Thickness and Density of Adsorbed Additive Layer onto Metal Surface
under Rolling Friction Evaluated by Means of Neutron Reflectometry

T. Hirayama, N. Yamashita1, S. Akimoto1, M. Fujimori1,
T. Matsuoka1, M. Hino2 and T. Oda2
Dept. of Mechanical Engineering, Doshisha University
Dept. of Mechanical Engineering, Doshisha University
2
Research Reactor Institute, Kyoto University
1

INTRODUCTION:
Tribology is one of academic
disciplines covering friction, wear and lubrication inengineering for a lot of industrial applications such as
bearings, gears, engine pistons in car and so on.
Formation of adsorbed additive layer on metal substrates
has attracted attention as an effective way to reduce
friction. There are a lot of studies investigating therelationship between the kind of additives and their
tribological properties, but the formation process of theadsorbed layer is still unknown. On these backgrounds,
this study investigated the formation and desorption
process of adsorbed additive layer onto metal surface bymeans of attenuated total refection infrared spectroscopy(ATR-IR) and neutron reflectometry (NR) with time slice
mode.
EXPERIMENTS:
Thin copper film was deposited
onto silicon wafer as target substrate for the study.
Poly-alpha-olefin and palmitic acid were selected as baseoil and oiliness additive, respectively. The timedependences of IR absorbance profiles and neutronreflectivity profiles are shown in Figs. 1 and 2. We cansee that the IR peaks from COO bonds gradually grown
up after the injection of base oil with oiliness additive.
On the other hand, the neuron reflectivity profiles did notchange regardless of time. These results indicated that thephysisorption of oiliness additive molecules was quickly
completed and the chemisorption was graduallyproceeded. To investigate the effect of rolling friction, we
designed the sample holders with rolling friction
mechanism for ATR-IR and NR. The obtained results areshown in Figs. 3 and 4. The IR profiles showed thedesorption of additive layer, but the NR profiles did notchange even after the rolling friction.

Fig. 1.

Fig. 2. Time dependence of neutron reflectivity profiles
obtained by SOFIA at BL16 in J-PARC MLF

Fig. 3.

Time dependence of IR absorbance peaks after
rolling friction

Fig. 4.

Time dependence of NR profiles after rolling
friction

CONCLUSIOINS: The additive molecules made thecondensed layer around the top surface by physisorption,and they gradually reacted by chemisorption. The rolling
friction process pealed the adsorbed additive molecules
off from the surface temporarily, but the layer was
quickly repaired. ATR-IR and NR were quite effective to
see the adsorption and desorption processes withseparating ‘physisorption’ and ‘chemisorption’.

Time dependence of IR absorbance peaks

採択課題番号 26020

中性子反射率法による摺動条件下における
表面添加剤吸着層の厚み・密度測定（同志社・理工）平山朋子、山下直輝、秋元翔太、藤森慎、松岡敬（京大・原子炉） 日野正裕、小田達郎
144

通常採択
共同通常

CO12-3

Characteristic Mesurement of Neutron Detector for Fukushima Debris

M. Kureta1, M. Komeda1, K. Takamiya2
1

Japan Atomic Energy Agency
Research Reactor Institute, Kyoto University

2

INTRODUCTION:
New hybrid detector called B-10+ detector has beendeveloped by GE Reuter-Stokes. The detector is what
combines B-10 lined proportional counter with He-3
counter. A big feature of B-10+ detector is reducing costs
while the performance doesn’t decrease much. We havedeveloped NDA system against the Fukushima debris,and then we are considering applying the B-10+ detector
instead of He-3 detector that has been most popular for
general NDA systems. The original experiment plan at
KUR was twice experiments at the B-4 port, and once
experiment with high gamma ray and neutron flux at thearea under the core. We could carry out the first experiment in 2014. In the experiment using the B-4 port, we
obtained fundamental data of B-10 detector such as thepulse shape and plateau.
EXPERIMENTS:
The B-10+ detector is 100cm in length. And the gaspressure including He-3 is approximately 1 atm. Threetypes of amplifiers were used. A current amplifier andcharge amplifier are developed by our group, and anotheris a charge amplifier from PDT Inc. He-3 detector (4 atm)
was also used in order to compare detection efficiency
with B-10+ detector. The high voltage power supply was
ORTEC 556H, DC supply was KIKUSUI PDM-3, andcounter was ORTEC 872.

Fig.1 Plateau measurements of B-10+ detector withthree kinds of amplifiers

1V
0.4μs

RESULTS:As shown Fig.1, the current amplifier and charge amplifier caused pile-up, which was also observed on an
oscilloscope. Therefore we measured neutron flux
through an absorber, the plateau region was observed
clearly. Due to the limited machine time, data of the attenuated flux was not obtained by using a current amplifier, and data after the plateau region was not done. Somemeasurements by He-3 were carried out. As an easy reference, measurement result by He-3 detector indicatesthat B-10+ detector has 40% detection efficiency of He-3
detector. Fig.2 shows a pulse from a charge amplifier onan oscilloscope. The width was approximately 1 μs thatwas the same degree as using He-3 at another measurement. Fig.3 shows an output spectra for a B-10+ detector.
A sharp peak of He-3 was not observed. The reason isconsidered that the effect of the He-3 gas is not stronger
than the lined B-10 since the amount of He-3 gas is reduced. We will investigate characteristics of B-10+ detector in high gamma ray field as future work. After that,
we will try experiments applying B-10+ detectors to
NDA system.

採択課題番号 26022（原子力機構）呉田

Fig.2 A pulse from B-10+ detector using acharge amplifierFig.3 B-10+ detector spectrum using a charge
amplifier

福島溶融デブリ測定用中性子検出器の特性評価研究
昌俊、米田 政夫（京大・原子炉）高宮 幸一

145

通常採択

CO12-4

Evaluation of Multiwire-type Two-Dimensional Neutron Detector
with Individual Line Readout

K. Toh, K. Soyama, T. Nakamura, M. Hino1, and T. Oda2
J-PARC Center, Japan Atomic Energy Agency
1
Research Reactor Institute, Kyoto University
2
Graduate School of Science, Kyoto University
INTRODUCTION: Multiwire-type two-dimensional
neutron detectors using helium-3 gas are widely used inneutron scattering experiment facilities because of theirhigh detection efficiency, low gamma-ray sensitivity, andexcellent long-term stability. We have developed anadvanced multiwire-type two-dimensional neutron
detector system without compromising the otherwise
excellent performance of the conventional detector [1, 2].
A short response time and better spatial resolution can beobtained in this system by using an individual line
readout method. Additionally, optical devices have beendeveloped and incorporated in the system forlong-distance signal transmission and insulation between
the detector heads and the signal processing circuits. In
this present study, we performed neutron irradiation
experiments at KUR.

Fig. Image of collimated neutron beam with size of 1 x 1
mm2.
Normalized signal (arb. unit)

101

EXPERIMENTS: The multiwire element, which isdeveloped for individual line readout, has 128 anodewires, 128 cathode wires for the y-axis, 128 cathodestrips for the x-axis, and a wire/strip pitch of 1 mm. The
amplifier-shaper-discriminator boards have a total of 256
channels to process each cathode signal line.
Field-programmable gate array based digital signal
processing and digital signal encoding are used to
calculate signal position with a sampling frequency of
106 MHz. Dedicated optical signal transmission devices
are designed to use multimode optical fibers at awavelength of 850 nm. List-mode data with the x- andy-positions and the time of flight are recorded using adata acquisition system (MPA-3, Fast Comtec). Neutron
irradiation is performed using a neutron beam line CN3 at
the KUR.

100
10-1
10-2
10-3
10-4
10-5

0

20

40
60
80
Position (mm)

100

120

Fig. 2 one dimensional response at peak position.
106
Measured signal (cps)105

RESULTS: Fig. 1 shows a typical response when a 1.0
× 1.0 mm2 neutron beam is irradiated on the detector, andthe response at the peak position onto the x- axis isshown in Fig. 2. As seen in Fig. 2, there are somebackground signals. It is considered that these signals
arise from neutron scattered by the beam line, thecollimator, the window and the fill gas. Fig. 3 shows thereactor power dependence to the measured counts of thedeveloped detector system. The developed detector
showed a linear response up to the full power, 5 MW, of
KUR reactor and the counting rate at 5 MW wasapproximately 2.1 x 105 cps.

2.1 x 105 cps

104
103
102
101
100
10-1
10-5

5 MW

10-4

10-3

10-2

10-1

Reactor power (MW)

100

101

Fig. 3 Measured counts of developed system under
neutron irradiation as a function of KUR reactor power.
REFERENCES:[1] K. Toh et al., Nucl. Instr. and Meth., 726 (2013)
169-174.
[2] K. Toh et al., J. Phys.: Conf. Ser. 528 (2014) 012045.

採択課題番号 26042
個別信号読み出し MWPC 二次元中性子検出器の特性評価（原子力機構）藤 健太郎、曽山 和彦、中村 龍也（京大・原子炉）日野 正裕（京大院・工）小田 達郎
146

通常採択

CO12-5

Development of Neutron Resonance Densitometry for
Nuclear Material Quantification in Melted Fuel

F. Kitatani1, H. Tsuchiya1, M. Koizumi, J. Takamine1, J.
Hori2, M. Sano2, K. Takahasi2, K. Nakajima2, and H.
Unesaki2
1
2

and the abscissa time interval after neutron pulse generations. The dips in the spectra around 192 and 102 ns areresonances of 183W at 7.64 eV and 27.0 eV, respectively.
Since the origin of the spectra is relevant to the beginningof electron pulse injection, the ends of the dips come lateras the electron pulse width increases. The dip at 27.0 eV
is not clearly seen with 4-s electron pulse width.

Research Group for Nuclear Sensing, JAEA
Research Reactor Institute, Kyoto University

INTRODUCTION: Neutron Resonance Densitometry(NRD) [1, 2] is an assay technique of nuclear materials inparticle-formed debris that contains various nuclides,
such as of structural materials and the others. It is a combination of two techniques: Neutron Resonance Transmission Analysis (NRTA) [3], and Neutron ResonanceCapture Analysis (NRCA) [4] or Prompt Gamma-ray
Analysis (PGA). Containing nuclides in a sample are
identified by NRCA/PGA. The information of
NRCA/PGA is used in NRTA analysis to quantify nuclear
material isotopes. A neutron time of flight (TOF) method
is used in NRD measurements. A facility consisting of aneutron source, neutron flight paths, and detectors, isrequired. One of the distinctive features is utilization of ashort flight path; this increases the neutron beam strength,
and reduces construction cost in a practical applications.
On the other hand, that reduces resolving power in TOF
measurements, and increases neutron background. Inorder to investigate the effect of neutron flight length, we
carried out NRTA experiments with a short neutron flightpath constructed at the Kyoto University Research Reactor Institute - Linear Accelerator (KURRI-LINAC).

SUMMARY: In measurements of NRD, the quantity of
the nuclear materials is determined from NRTA spectra in
the neutron energy range of less than 30 eV [1, 2]. At
KURRI-LINAC, we have examined NRTA with a 7-m
flight path. The resonance dips of 183W at 27 eV wassuccessfully observed with an electron pulse width lessthan 2 μs. This indicates the applicability ofshort-flight-path TOF system to nuclear material quantification. The importance of the pulse width of neutron
beam should be noted. Both simulation studies and experiments are expected for realistic design of a TOF facility of nuclear material quantification.

EXPERIMENTS: Experiments were carried out with a
7.5-m flight path. The experimental room and the neutron
source were separated by 2-m-thick concrete wall. A
2-m-long neutron transport tube was installed in the experimental room as shown in Fig. 1. The center of it wasan Al vacuum chamber, the cavity of which was 200 mm
in diameter; both sides were shielded by 2-mm-thick Al
plates. The chamber was surrounded by 5-mm-thick
B4C-doped silicone rubber (B4C 40%). The outside of therubber was high density polyethylene plates (460 x 460mm). The neutron beam was collimated to be 50 mm indiameter in front of the transport tube. A 6Li scintillation
detector (Saint-Gobain GS20; 100 x 100 x 10 mm) wasused to measure transmission neutrons. The incident neutron flux was monitored by a BF3 neutron detector placednear the exit of the concrete wall.
Sample and filter plates (100 x 100 mm) were placed in
front of the transport tube: In (0.2 mm), Ag (0.25 mm), W(0.5 mm), and Pb (10 mm). The neutron pulse width wascontrolled by the pulse width of the LINAC electron
beams, which were 500 ns, 2 μs and 4 μs.

Fig. 1. A neutron transport tube. A neutron detector wasplaced on the table.

Fig. 2. TOF neutron transmission spectra. The baselines are adjusted, and the curves are added for the sakeof readers.
REFERENCES:[1] H. Harada et al., Nuclear Data Sheets 118, p502
(2014).
[2] F.Kitatani et al., J. Nucl Sci. Tech. 51, p1107 (2014)[3] P. Schillebeeckx et al., Nuclear Data Sheets 113,
p3054 (2012).
[4] P. Schillebeeckx et al., JINST 7, C03009 (2012).

RESULTS: Figure 2 shows TOF neutron transmission
spectra. The ordinates are the normalized neutron counts,

採択課題番号 26044
中性子共鳴濃度分析法による溶融燃料等の核物質定量技術開発 通常採択
（原子力機構）北谷文人、土屋晴文、小泉光生、高峰潤（京大・原子炉）堀順一、佐野忠史、高橋佳之、中島健、宇根崎博信
147Test of a Microcell Multi-Wire Proportional Chamber for a Muon-Electron
Conversion Search Experiment, DeeMe

H. Natori, N. Abe1, M. Aoki2, Y. Igarashi, S. Ito2, S. Mihara, D. Nagao2, T. D. Nguyen2, T. M. Nguyen2, H.
Nishiguchi, Y. Seiya3, K. Shimizu3, T. Takahashi1,Y.
Takezaki3, N. Teshima3, K. Yamamoto3

after the blinded period. Because of the very high andrapid voltage up and down motion, readout electronics
suffers from large current input derived from the HV
switching. We also developed a readout system which
tolerates to high current input.

High Energy Accelerator Research Organization (KEK)
Research Reactor Institute, Kyoto University
2
Department of Physics, Osaka University
3
Department of Physics, Osaka City University

y[cm]

1

y[cm]

CO12-6

0.3

1400

0.3

1400

0.2

1200

0.2

1200

0.1

1000

0.1

1000

800

0

600

-0.1

INTRODUCTION: DeeMe [1] pursue mu-e conversion in nuclear field, which will be a clear evidence of the
new physics if it is found, because Standard Model of
elementary particle physics predicts it beyond an experimental reach. Detector is required to measure electron
momentum precisely after a huge pulse of prompt timing
charged particles, whose width and instantaneous hit rateis expected to be approximately 200ns and 70GHz/mm2.
Such a large input will make usual wire chamber detectors inactive due to space charge effect. We developed a
new technique to make a chamber to be tolerant to a large
input pulse.

Acrylic board& PMTsCherenkov light

1200

ADC

Accelerator

e- gunPulse electron Field emission electrons
200ns width
Flat time distribution
within 4us of RF injection

ND filter
Attenuate 10-3

0

0.14
x[cm]

0

600
400

-0.2
-0.3
-0.14

200
0

0.14
x[cm]

0

RESULTS: Fig. 3 shows an output result of the chamber. Electrons from beam gun tuned to be 70GHz/mm2 ininstantaneous hit rate are not amplified in the chamberwith applying pulsed high voltage to potential wire. This
enabled single electron detection coming after the burst
pulse. Noise derived from the HV switching is always thesame, so we can eliminate the noise by subtracting averaged waveform of plural numbers of events. We succeeded to obtain a clear electron signal after the burst
pulse avoiding the space charge effect by a burst pulse of
charged particles.
Noise by HV switching/work/deeme/data/kurri-201501//run02415.mid event number 121 channel 7

1000

MWPC

Accelerator

Collimator

200

-0.1

Fig. 2 Calculated electrical field contour. Anode-wire 1450V, Potential-wire 0V(left figure),
1450V(right figure)

EXPERIMENTS: Experimental setup is shown schematically in Fig. 1. Electron beam collimated to 16mm x
19mm penetrates Multi-Wire Proportional Chamber(MWPC) and beam counters. Beam rate is tuned changing current of electron gun heater.
Intensity control byheater power

400

-0.2
-0.3
-0.14

800

0

- A certain event- Average of many events- Subtracted waveform

800

Plastic
scintillator
& PMT

600

400

Singleelectron signal
200

Fig. 1 Schematics of experimental setup

0
52000

A huge pulse of prompt timing is emulated by tuned
pulse from electron beam gun. Delayed electron signals
are emulated by field emission electrons.
Electrical field contour inside the chamber calculated isshown in left of Fig. 2. Anode wires with 1450V and potential wires with 0V are put alternately. During a huge
pulse are coming, potential wires are applied with 1450V
as shown in right of Fig.2. With this setting, slope ofelectric field near anode wire become gentle that avalanche multiplication is suppressed. Temporary muting
the chamber during a burst pulse is expected to help tosuppress the space charge effect. Rectangular pulsed highvoltage is applied to potential wire to recover quickly

IHit^1

54000

56000

58000

60000

62000
time [ns]Fig. 3 Waveform of the chamber with electron
beam gun pulse and HV swithing

REFERENCES:[1] H. Natori, on behalf of the DeeMe Collaboration,
Nucl. Phys. B Proc. Suppl. Vol. 248-250 (2014)" r8jKlaJc:v
"hv

]R<5

"

通常採択

x  y3/;u&-BX#g0,$.Nx'6!.8[yqn=%wT)Mxp6!\ysPUW(fF7m     o>6Sx6pC6!\yZV9`Z_dY
bA*LG@eO?Q4E
148

CO12-7Ethnographic Study of Nuclear Reactor

M. Takagaki1,2, G. Shimazaki1, S. Masunaga3

self-righteously, once it fall into a little collapse,
lack of resilience of human wisdom for stabilization
and repair becomes embody.
By analyzing the narrative concerning the reactorof nuclear researchers, to describe the ethnographyof nuclear reactor and nuclear waste that is also a
study object of researchers themselves seems tolead to development of a new approach to themethodology of cultural anthropology. Such ethnography seems to be very useful for human society
by targeting to nuclear reactor as thing. Many nuclear physicists have focused on the following
statement of Prof. Wolfgang Weiss;

1

College of Nursing, Aino University
Graduate School of Human and Environmental Studies,
Department of Anthropology, Kyoto University
3
Graduate School of Science, Research Reactor Institute,
Kyoto University
2

Aside the pros and cons of the use of nuclear
power as an energy source, it seems to be useful inunderstanding the nuclear reactors to describe themas an ethnography based on the narrative data of
nuclear researchers. By describing the reactor as ascientific ethnography, it is expected to be highlighted the problem of nuclear reactors andlow-level radiation environment from a new angle.
Then, it is expected to provide further knowledge
for living in the contact zone between the field welive in safely (normal) and low-level radiation field(pathological), and going into patho and/or coexisting with patho.
This is a very unique study that an ethnographer
who is a radiation physicist, a physician and also ananthropologist participates in wide-range observation of nuclear research. The researchers have been
forced to include Fukushima as an enlarged research
field, and it is regarded as a chance to write up theexcellent scientific ethnography by doing this rather.
On 2014-2015, we have mainly investigated previous research, and preliminary investigation has been
carried out with biologists and physicists involvedin nuclear science at the Kyoto University. Theirnarrative indicated here was traumatic narrative of
Fukushima that suddenly appeared in their research
field of nuclear science. Sometime it was a narrativeof the confusion of the researchers themselves, although almost of the nuclear scientists have investigated sincerely with the nuclear reactor research as
an energy source of the human being. The radioactivity that has been discarded and released has been
completely isolated in a managed environment fromthe living space. Conversely, by this act, understanding of nuclear reactors and low-level radiation
environment, and also constructing networks among
various sub-specialists structurally become difficult.
The reason why researcher's confusion about Fukushima accident is so strong, I think because our
wisdom as the central pillar of our ego might be extremely imbalanced state. As being symbolicallyshown in Fukushima, because wisdom of nuclear
sciencehas
extremely
hypertrophied“The most serious damage caused by Fukushima
accident is that people lost trust for science andscientists. This certainly will influence long- term
human history, and we cannot recover such situation so easily. We scientists are responsible to suchsituation.”
Latour has pointed out that the dynamic and contingent elements intervene in the process of establishing the level of intellectual authority and knowledge
that circulates within the scientific community. Caseof Fukushima accident shows this extremely andplainly. It is expected to also lead to scientificachievements, such as actor network theory by scientific anthropological comparison analysis of thevarious disciplines of nuclear reactor researchers as
different cultures. And also, ethnographic researchmight be very helpful tool for well public understanding of reactor and/or low dose radiation field,
and then might regain confidence of scientists.
The understanding and knowledge of the researchers of KUR for their acceptance of this ambitious study is greatly appreciated. A new division
for Ethnographic Study for Nuclear Science is expected to be established in KUR. This research is
supported by Grant-in-Aid for Scientific Researchfor 2014-2016, No.26580152, JSPS. We are now
promoting our fieldwork and are planning to publish
ethnography of nuclear reactor on 2017.
REFERENCES:[1]K. Azuma, et al., Sekaishiso-sha. (2014)[2]B.Latour, Routeldge.(2013)[3]W.Allison, Wada Allison Pub. (2009)[4]AESJ, Fukushima Accident Report. Shinppyo-sha.
(2014)

	 採択課題番号26051
原子炉の人類誌	
 （藍野大学）高垣政雄、島崎義孝、（京大炉）増永慎一郎	
 
149

通常採択	
 

CO12-8

Effective Measures on Safety, Security, Hygiene and Disaster Preventionin Laboratories
USE & MANAGE OF SMALL AMOUNT of U & Th:
When using small amount of uranium or thorium up to
300g (DU, NU) and/or 900g (Th), most of safety control
procedures requested as radioactive materials are exempted by related regulations. Weighing control of nuclear elements is only requested by regulation. This
causes easy usage of uranium and thorium in laboratories.
For example, it is convenient that uranium acetate or uranium nitrate could be used for biology research to observe chromosomes clearly. Natural occurring radioactive
materials (NORM) such as minerals and seawater samples including uranium and thorium would also be troublesome sources which could be enriched through someresearch processes, and then would change into highconcentration radioactive materials as a result legally.
This is a representative technologically enhanced NORM(TENORM). TENORM is one of headache materials inlaboratory. Even the amount is quite small, the nuance ofterms of “nuclear” “uranium” and “thorium” will give a
big impact on society when some accidents or troubles
happen. We can use these materials easily and conveniently, however these are strictly controlled by the international regulations on their transfer. The latest guideline
on NORM and TENORM safety management by theJapanese regulatory body was published in 2009 to support the safety management. These situations must be
identified and understood by all stakeholders. Frameworkof related education for safety managers and users should
be adequately established and applied. All stakeholders
should understand their risk level and features of nuclear
materials as radioactive materials. This could lead reasonable and optimized safety management in laboratories.

T. Iimoto1, R. Hayashi1, T. Saito1, A. Yasmi1, S. Higaki1,
A. Sugiyama1, N. Kutsuna1, A. Kobashi1, K. Tanoi1, T.
Suzuki1, K. Kamiko1, T. Takahashi2, S. Takahashi2
1
2

The University of Tokyo
Research Reactor Institute, Kyoto University

INTRODUCTION:
Important research aspects can be found in the following
keywords such as safety, security, hygiene and disasterprevention. Nuclear research reactor is one of representative facilities together with these keywords under theiroperation. It is effective to investigate the latest status onpractical measures on these keywords in various facilities
including nuclear research reactors, to compare each other among facilities, and to discuss more effective or optimized ones for our positive safety management.
Through this process, it is also effective to investigate thelatest international and/or national regulations and the
movement of revision of them. This total discussion contents and its fruit are directly useful for all relating laboratories.
RESEARCH APPROACH:
General research approach is as follows.
- Measures of safety management during operation or
standstill status of the real facilities would be investigated. This information would be used for our research
discussion on the positive and more optimized safety
management.
- It would not be a single year research, but maybe two to
three years research for one theme.
- Information source of facilities would not be only KUR,
KUCA or the other facilities in Kyoto University, butalso the Kinki university research nuclear reactor or thefacility of National Institute of Fusion Science, etc. This
research is an active joint-research with these relating
facilities and positive researchers on safety management.
- One of the distinctive features of this research is to involve office staffs as cooperators as well as researchers
and technical staffs. In The University of Tokyo, most of
the members in Division for Environment, Health and
Safety are office staffs who knows real situation ofsafety management in laboratories very well.

NEXT RESEARCH TARGETS;
Education framework, curriculum and textbooks forsafety managers and users as well as relating officers tofill up the nuclear material controlling sheet for the use ofsmall amount of uranium and thorium should be discussed. This discussion should be based on the additional
investigation and analysis of the way to use, control andstorage the materials in laboratories.
REFERENCES:[1] T. IIMOTO, Environ. & Safety, 4(3),1-8 (2013)

Discussion target in BY of 2014 was determined as“safety control in use of small amount nuclear materials”
through our internal member discussion. We investigated
the related regulations and their application as well as thefact-finding in use of small amount of uranium and thorium in Japanese laboratories.

[2]T. IIMOTO et.al., Safety Engineering,48(4),215-221(2009)[3] T.IIMOTO et.al., Isotope News, 566,64-67, (2001)[4] MEXT, Guideline for Safety Management of NORM
and Consumer Products (2009)

採択課題番号 26054

実験施設における安全衛生・セキュリティ・防災等の通常採択
効果的な対応と対策に関する研究(東大)飯本武志、林瑠美子、齊藤拓巳、安見厚志、桧垣正吾、杉山 暁、朽名夏麿、小橋浅哉、
田野井慶太郎、鈴木崇彦、神子公男、布川 淳、小原佑介、前寺郁彦（京大・原子炉）高橋知之、
高橋千太郎

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CO12-9Development of New NiMo Neutron Mirror for Fundamental Physics

Y. Arimoto1, P. Geltenbort2, S. Imajo3, Y. Iwashita4,
M. Hino5, R. Katayama6, M. Kitaguchi7, K. Mishima1, R.
Sakakibara7, Y. Seki8, H. M. Shimizu7 and T. Yoshioka9

The facts of (1) and (2) help us to understand what phenomenon occurred while NiMo ingot evaporating. These
are as follows:1

KEK,2ILL, 3Dep. of Phys. Kyoto Univ.,4ICR Kyoto Univ.,
KURRI, 6Dep. of Phys. Univ. of Tokyo, 7Dep. of Phys.
Nagoya Univ., 8Sch. of Eng. Univ. of Tokyo, 9Dep. of Phys.
Kyushu Univ.
5(a) There is a possibility that NiMo ingot material included gasses and it caused bumping phenomenon of(2). If it true, gasses could also affect the density decrease of (1).
(b) The deposited NiMo films preserve the nature of NiMo alloy; Otherwise, the density of test samples
should close to the one expected for Ni, 8.9 g/cm3,
because the Ni vapor pressure is 105 times higher than
Mo at 2000 K.
(c) In spite of (b), the vapor pressure of NiMo alloy wasquite low. Probably, NiMo vapor was not efficiently
transported at substrates from evaporation source position, which could cause the density decrease of (1).
(d) There is a possibility that the crystal structure of thedeposited NiMo films varied from that of NiMo ingot.
If it true, it could affect the density decrease of (1).

INTRODUCTION: A large amount of CP violation(CPV) is necessary to solve matter and anti-matterasymmetry problem in the universe. However, theamount of CPV standard model predicts is too insufficient to explain it. The fact indicates that the new physics
beyond standard model (BSM) exists and supplies thelack of CPV. The neutron intrinsic electric dipole moment(nEDM) is sensitive to CPV that BSM provides. Therefore, we can effectively search BSM with precise nEDM
measurement.
The nEDM can be obtained from the ultracold neutron(UCN) spin precession in a storage container under homogeneous electric and magnetic fields. In the experiment, the loss of UCNs and their polarization occur due
to interaction between UCNs and wall material, whichmake statistical precision worse. It is therefore important
to develop new wall material with low loss probabilities.
On the other hand, in the case that UCNs are transported
from a pulsed UCN source, by decelerating fast UCNs
and/or by accelerating slow UCNs properly, these UCNs
can be focused on a storage container at the same time,
which achieves drastic improvement of statistical precision [1]. However, if diffuse scattering induced by roughwall arises, the degree of improvement decreases. It is
hence also important to develop a wall material with assmooth surfaces as neutron mirrors have.

(a), (b), (c) and (d) give us quite an important information
for next desirable fabrication test with vacuum evaporation deposition. First, we should use degassed NiMo ingot to solve the problem of (a). Second, to compensate
the shortage of NiMo vapor pressure ((b) and (c)), a next
vacuum evaporated deposition should be conducted byattracting ionized NiMo vapor to substrates with a bias
voltage. Third, to avoid structure change of (d), Ni andMo are evaporated simultaneously so that the composition of deposited NiMo film becomes 15 weight percent
and 9.1 g/cm3.
SUMMARY: The material with low loss probabilities
and smooth surfaces is desired for nEDM experiment.
NiMo of 15 weight percent and 9.1 g/cm3 is known as
one of the promising low loss materials. We therefore
fabricated test samples using NiMo ingot with KURRI
vacuum evaporated apparatus. Although we succeeded in
NiMo film deposition itself, the densities of test samples
were only 6.3 to 6.6 g/cm3, and these surfaces were toorough to use neutron mirrors. To solve these problems, it
is desirable that next fabrication with vacuum evaporation deposition should be performed using two evaporation source of degassed Ni and Mo ingot, and by attracting ionized NiMo vapor to substrates with a bias voltage.

Ni-Mo FABRICATION WITH VACUUM EVAPORATED MACHINE: Nickel-Molibdenum alloy (NiMo)
of 15 weight percent and 9.1 g/cm3 is known as one ofthe promising low loss materials. We fabricated test samples made of NiMo with KURRI vacuum evaporated
apparatus and aimed for 100 nm thickness on SUS304
and Si-wafer substrates.
RESULT AND CONSIDEREATION: We succeeded in
NiMo film deposition itself. However, two undesirable
features appeared as follows:

REFERENCES:[1] Y. Arimoto et al., Phys. Rev. A86 (2012) 023843.

(1) The densities of test samples were only 6.3 to 6.6
g/cm3 by measuring XRR, which is far less than expected value, 9.1 g/cm3. Hence, our deposited NiMo
film cannot be used as a wall material for nEDM.
(2) In this fabrication, a bumping phenomenon could not
be suppressed. Consequently, these surfaces were sorough that it could not be used as neutron mirrors.

採択課題番号 26059 題名白色ビーム対応多層膜中性子干渉計のためのスーパーミラーの開発 II（東大院・工）関義親（名大院・理）北口雅暁（京大原子炉）日野正裕

151

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