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Hiraoka, Hirokazu; Komatsuzaki, Joji*; Hanaka, Norihiko*; Okamoto, Akiko; Saito, Yoshihiko*; Munakata, Masahiro; Togawa, Orihiko
JAEA-Technology 2022-003, 70 Pages, 2022/07
JAEA-Technology-2022-003.pdf:2.53MB
In contamination inspections for public in nuclear emergency, it is assumed that a large number of motor vehicles and evacuees will be inspected. At present, first measurement points of vehicles are tires and around a wiper, and they are basically inspected by persons using portable radiation surface contamination meters such as GM survey meters. However, in order to efficiently inspect contamination of vehicles, utilization of portable radiation portal monitors is being considered for the inspection. In this study, examination of performance of the portal monitor was conducted in order to obtain basic data. In this examinations, sealed radiation sources, 
Ba, were substituted for the contamination of Operational Intervention Level 4 (OIL4), the evaluation criteria to conduct simple decontamination in the contamination inspection. The radiation source was attached practically to a tire and around the wipers of a vehicle, and the counting rate of 
-rays from the radiation sources was measured using the portal monitor. Three examinations were conducted: static examination with a vehicle stationary, moving examination to mock the actual inspection, and high back ground examination to investigate performance of the equipment in high back ground environment. The vehicle mainly used in the experiments was a sedan, which is generally used as standard vehicles. And, a van whose front body is like that of a bus was used at this experiment. In addition, the "Gamma Pole" manufactured by the Chiyoda Technol Corporation was used as the portal monitor. As the result, it was estimated that the case of contamination equivalent to 40,000 cpm, the default value of the OIL4, deposited on the tread on a vehicle tire, when the vehicle passes through the portal monitor at 10 km/h or less, the contamination would be detected with a probability of 99% or more. Similarly, when the contamination deposited on around the wipers and the vehicle speed is 5 km/h or less,
Hiraoka, Hirokazu; Hokama, Tomonori; Munakata, Masahiro
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 5 Pages, 2019/05
Neighboring inhabitants of nuclear facilities must evacuate according to an ambient dose rate at a nuclear accident. The evacuation is judged by the measured value by monitoring posts (MPs). However, if the measured value increase by artificial radionuclide deposited to MP, it is considered that the dose rate of the surrounding environment is overestimated. The purpose of this research is to evaluate exactly the dose rate even if the radionuclide deposit to the MP, in order to adequately evacuate inhabitants. Just a MP and horizontal ground was simulated. To calculate ambient dose rates from the roof surface of MP and ground surface, Monte Carlo calculation was done. And, it was obtained that the ratio which the dose rate from the roof account for sum of two these dose rates. According to the result, the ratio was 42%. It suggested that the radionuclide could increase the measured value. However, because simulated system was simple, it is considered that the ratio was overestimated.
Yoshida, Masahiro*; Ishii, Kenji; Jarrige, I.*; Watanuki, Tetsu; Kudo, Kazutaka*; Koike, Yoji*; Kumagai, Kenichi*; Hiraoka, Nozomu*; Ishii, Hirofumi*; Tsuei, K.-D.*; et al.
Journal of Synchrotron Radiation, 21(1), p.131 - 135, 2014/01
Times Cited Count：3 Percentile：18.95(Instruments & Instrumentation)
Jarrige, I.*; Nomura, Takuji; Ishii, Kenji; Gretarsson, H.*; Kim, Y.-J.*; Kim, J.*; Upton, M.*; Casa, D.*; Gog, T.*; Ishikado, Motoyuki*; et al.
Physical Review B, 86(11), p.115104_1 - 115104_4, 2012/09
Times Cited Count：8 Percentile：35.26(Materials Science, Multidisciplinary)We report the first observation by momentum-resolved resonant inelastic X-ray scattering of charge excitations in an iron-based superconductor and its parent compound, PrFeAsO
and PrFeAsO respectively, with two main results. First, using calculations based on a 16 band 
model, we show that the energy of the lowest-lying excitations, identified as 
interband transitions of dominant 
, 
orbital character, exhibits a dramatic dependence on electron correlation. This enables us to estimate the Coulomb repulsion 
and Hund's coupling 
, and to highlight the role played by in these peculiar orbital-dependent electron correlation effects. Second, we show that short-range antiferromagnetic correlations, which are a prerequisite to the occurrence of these excitations at the 
point, are still present in the superconducting state.
Jarrige, I.; Ishii, Kenji; Yoshida, Masahiro; Fukuda, Tatsuo; Ikeuchi, Kazuhiko*; Ishikado, Motoyuki*; Hiraoka, Nozomu*; Tsuei, K.-D.*; Kito, Hijiri*; Iyo, Akira*; et al.
Physica C, 470(Suppl.1), p.S377 - S378, 2010/10
Times Cited Count：4 Percentile：21.9(Physics, Applied)
Ir radiation sources for intravascular irradiationKogure, Hiroto; Sorita, Takami; Iwamoto, Seikichi; Nagata, Yasushi*; Hiraoka, Masahiro*; Iwata, Kazuro*; Kawauchi, Yukimasa*; Suzuki, Kazutoshi*
JAERI-Tech 2003-003, 26 Pages, 2003/03
JAERI-Tech-2003-003.pdf:4.83MB
Intravascular brachytherapy is a novel therapy for preventing the restenosis of coronary artery by use of low-dose irradiation. JAERI and Kyoto University have been developing Ir radiation sources by the cooperative research project entitled as "The research on safety and effectiveness of the intravascular brachytherapy for preventing restenosis of the coronary artery disease" since 1998. The radiation source was introduced into the stenosis through a catheter (a guide-tube to insert directly into vascular) to irradiate the diseased part. Ten Ir seed sources (
0.4 mm 
2.5 mm) were positioned between nylon spacers (0.3 mm 1.0 mm) in a flexible covering tube and the tube was plugged with a core-wire; the tube was shrunk to fix the inside materials and the size is 0.46 mm in diameter and 3 m in length. The physically optimal design was determined to insert the radiation source easily into vascular and to get the dose uniformity in the diseased part. The production method of the radiation source, which is practical to use in the clinics was also established.
Sogabe, Toshiaki; Ishihara, Masahiro; Baba, Shinichi; Kojima, Takao; Tachibana, Yukio; Iyoku, Tatsuo; Hoshiya, Taiji; Hiraoka, Toshiharu*; Yamaji, Masatoshi*
JAERI-Research 2002-026, 22 Pages, 2002/11
JAERI-Research-2002-026.pdf:2.41MB
Carbon Fiber Reinforced Carbon-carbon Composites, C/C composites, have been developed and extensively studied their characteristics. C/C composites are considered to be promising materials for the application of a control rod in the next high performance high temperature gas-cooled reactors. In the present paper, details of the development of the candidate C/C composite are described. In the course of the development of the material, especially, feasibility of the production, stableness of the supply and cost are much taken into consideration. As the physical properties of the material, high mechanical strength such as tensile and bending, high fracture strain and fracture toughness and low dimensional change by neutron irradiation have to be met. The developed 2D-C/C composite consists of plain-weave PAN-based carbon fiber cloth and pitch derived matrix. Also, high purification up to the level of nuclear grade was successfully attained in the composite.
Ishii, Kenji; Jarrige, I.; Ikeuchi, Kazuhiko; Yoshida, Masahiro; Ishii, Hirofumi*; Hiraoka, Nozomu*; Toyokawa, Hidenori*
no journal, ,
no abstracts in English
Jarrige, I.; Ishii, Kenji; Ikeuchi, Kazuhiko*; Yoshida, Masahiro; Ishikado, Motoyuki; Hiraoka, Nozomu*; Tsuei, K.-D.*; Iyo, Akira*; Eisaki, Hiroshi*; Kito, Hijiri*; et al.
no journal, ,
A prerequisite to elucidate the mechanism underlying superconductivity in the iron oxypnictides is an in-depth knowledge of the low-lying electronic excitations. In an attempt to unveil those low-energy excitations, we have performed a resonant inelastic X-ray scattering (RIXS) measurement at the Fe K edge in a single crystal of the underdoped superconductor compound PrFeAsO (Tc = 42 K). We discern a feature centered around 4 eV which is reminiscent of the metal-ligand charge transfer in the cuprates, therefore we are tempted to ascribe it to the charge transfer between Fe 3d and As 4p.
Jarrige, I.; Ishii, Kenji; Fukuda, Tatsuo; Yoshida, Masahiro; Ishikado, Motoyuki; Shamoto, Shinichi; Hiraoka, Nozomu*; Tsuei, K.-D.*
no journal, ,
Hiraoka, Hirokazu; Hokama, Tomonori; Munakata, Masahiro
no journal, ,
Neighboring inhabitants of nuclear facilities must evacuate according to an ambient dose rate at a nuclear accident. The evacuation is judged by the measured value by monitoring posts (MPs). However, if the measured value increase by artificial radionuclide deposited to MP, it is considered that the dose rate of the surrounding environment is overestimated. The purpose of this research is to evaluate exactly the dose rate even if the radionuclide deposit to the MP, in order to adequately evacuate inhabitants. Just a MP and horizontal ground was simulated. To calculate ambient dose rates from the roof surface of MP and ground surface, Monte Carlo calculation was done. And, it was obtained that the ratio which the dose rate from the roof account for sum of two these dose rates. According to the result, the ratio was 44%. It suggested that the radionuclide could increase the measured value. However, because simulated system was simple, it is considered that the ratio was overestimated.
