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Tanimura, Yoshihiko; Fujii, Katsutoshi; Tsutsumi, Masahiro; Yoshizawa, Michio
Progress in Nuclear Science and Technology (Internet), 4, p.388 - 391, 2014/04
Mono-energetic neutron calibration fields have been developed at Facility of Radiation Standards (FRS) using a 4 MV Pelletron accelerator. The neutron energies are available between 8 keV and 19 MeV for determining the energy responses of neutron dosemeters. The neutron energies are well adjusted to the energy points specified in the international standard (ISO 8529-1) and Japanese standard (JIS Z4521). Precise neutron fluence is the most important parameter for the calibration. In order to determine the fluence a Long Counter (hereinafter LC) is installed in the field for monitoring the neutron emission rate from the target. The fluence can be precisely determined using the output counts of the LC, the distance from the target, calibration coefficient of the LC and the air attenuation factor. This presentation describes the neutron monitors, outline of our monitoring system, determination of the air attenuation factor and procedure to determine the neutron fluence.
Yamada, Katsunori; Fujii, Katsutoshi; Kanda, Hiroshi; Higashi, Daisuke; Kobayashi, Toshiaki; Nakagawa, Masahiro; Fukami, Tomoyo; Yoshida, Keisuke; Ueno, Yumi; Nakajima, Junya; et al.
JAEA-Review 2013-033, 51 Pages, 2013/12
JAEA-Review-2013-033.pdf:2.73MB
After the accident at Fukushima Dai-ichi Nuclear Power Plant, various numerical criteria relevant to radiation protection were defined. We surveyed these criteria through internet. As a result of survey, the following 13 items were identified: (1) criteria for taking stable iodine tablets, (2) criteria for the screening of surface contamination, (3) evacuation area, sheltering area, etc., (4) activity concentrations in food, drinking water, etc., (5) dose limit for radiation workers engaged in emergency work, (6) guideline levels of radioactive substances in bathing areas, (7) criteria for use of school buildings and schoolyards, (8) restriction on planting rice, (9) acceptable activity concentrations in feedstuff, (10) acceptable activity concentrations in compost, (11) criteria for export containers and ships, (12) criteria for contaminated waste, (13) standards for radiation workers engaged in decontamination work. In this report, the basis of and issues on these criteria are summarized.
Nakagawa, Masahiro; Nojima, Shun; Fujii, Katsutoshi; Shishido, Nobuhito; Sakai, Toshiya; Umehara, Takashi; Shimizu, Isamu
Hoken Butsuri, 47(3), p.189 - 193, 2012/10
It is essential to wear an air-purifying respirator in the radiation works in a contaminated atmosphere. A breath-responsive-powered air-purifying respirator (BR-PAPR) has been recently developed. However, no research has yet been conducted to determine the protection factor (PF) of the BR-PAPR in actual workplaces. In this study, the PFs of the BR-PAPR were measured by a man-test apparatus and compared with those of a non-powered full face mask. The PFs were measured under three different situations; normal wearing condition, clogging the filter and leaving a gap between the face and the mask. Under these situations, it was found that the PFs of the BR-PAPR are higher than those of the non-powered full face mask. PFs greater than 4000 were obtained for 95% of the subjects who wear the BR-PAPR, and PFs over 6667, the upper limit of the man-test apparatus, were obtained for 49% of them. The questionnaire survey was conducted for workers. The results showed that the workers feel a reduced burden when they wear the BR-PAPR. The results of this study showed high protection performance and operation efficiency of the BR-PAPR.
Shimizu, Shigeru; Fujii, Katsutoshi; Kawasaki, Tomokatsu
JAEA-Technology 2010-005, 72 Pages, 2010/06
JAEA-Technology-2010-005.pdf:2.44MB
In the Japanese Industrial Standard, JIS Z 4511 sets the condition of X-ray reference fields to be used for the performance test of radiation measuring instruments for radiation protection. With the soft X-ray generator installed in the Facility of Radiation Standard in Nuclear Science Research Institute, we have established four series of soft X-ray reference fields with quality index 0.6, 0.7, 0.8 and 0.9 based on JIS Z 4511. In this process, quality of the X-ray fields, X-ray spectra, conversion coefficients to the dose equivalent from Air-Kerma were evaluated in the soft X-ray fields produced with X-ray tube voltage ranging from 6 kV to 100 kV. As a result, it is found that dose equivalent standard with good precision and wide range of test energy point and dose rates can be provided, this report describes these detailed data.
O moderated 
Cf source at JAEA and KAERIKowatari, Munehiko; Fujii, Katsutoshi; Tsutsumi, Masahiro; Kim, B.-H.*; Lee, K.-C.*; Yoshizawa, Michio; Yamaguchi, Yasuhiro
Journal of Nuclear Science and Technology, 45(Suppl.5), p.217 - 220, 2008/06
Times Cited Count：1 Percentile：9.77(Nuclear Science & Technology)no abstracts in English
O-moderated Cf sourceKowatari, Munehiko; Fujii, Katsutoshi; Takahashi, Masa; Yoshizawa, Michio; Shimizu, Shigeru; Kawasaki, Katsuya; Yamaguchi, Yasuhiro
Radiation Protection Dosimetry, 126(1-4), p.138 - 144, 2007/08
Times Cited Count：5 Percentile：36.49(Environmental Sciences)The facility of the Radiation Standards (FRS) of the Japan Atomic Energy Agency was equipped with the reference neutron field by using DO moderated Cf neutron source (DO-Cf), with a 30cm diameter DO sphere. In order to determine the characteristics of the reference field within the ranges of calibration distance (75 to 200 cm from the center of the source to the calibration point) in detail, the authors performed the evaluation of the neutron spectra and neutron fluence rate at various distances from the DO moderated source assembly by computations using MCNP-4C and by experimental studies using Bonner Multi-sphere neutron Spectrometer (BMS). Due to the volume neutron source, it is difficult to measure the contribution of the scattered neutron component with the desirable accuracy by shadow-cone method. In this study, the net counting rate of each counter of BMS was corrected by estimating the ratio of the counting rate of each counter in condition of the experimental and the ideal arrangement by the Monte Carlo calculation. The spectra of the direct component were unfolded by using the corrected counting rate with SAND II code. The averaged dose conversion coefficients (h
(10) and h
(10)) and neutron dose rates (H(10) and H(10)) at various distance were estimated based on the measured spectra. The effectiveness of the correction was discussed by comparing the measured and calculated values. Additionally, the suitable distance for the calibration of personal dosimeter at FRS reference field was evaluated by the results.
Fujii, Katsutoshi; Kowatari, Munehiko; Kawasaki, Katsuya
Hoken Butsuri, 41(3), p.175 - 179, 2006/09
no abstracts in English
Fujii, Katsutoshi; Kawasaki, Katsuya; Kowatari, Munehiko; Tanimura, Yoshihiko; Kajimoto, Yoichi; Shimizu, Shigeru
JAEA-Testing 2006-005, 146 Pages, 2006/08
JAEA-Testing-2006-005.pdf:19.71MB
4MV Van de Graff accelerator was installed in the Facility of Radiation Standards (FRS) in June 2000, and monoenergetic neutron calibration fields and high energy 
-ray calibration fields have been developed. The calibration fields are provided for R&D on dosimetry, and for the calibration and type-test of radiation protection instruments. This article describes the operational procedure, the maintenance work and the operation of the related apparatuses of the accelerator. This article focuses on the sufficient safety and radiation control for the operators, the maintenance performance of the accelerator, and on the prevention of the malfunction due to the mistakes of the operator. This article targets the unexperienced engineers in charge of operation and maintenance of the accelerator.
Takahashi, Masa; Fujii, Katsutoshi; Tanimura, Yoshihiko; Shimizu, Shigeru; Kajimoto, Yoichi; Kowatari, Munehiko; Yoshizawa, Michio; Yamamoto, Hideaki
Dai-18-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.110 - 113, 2005/11
no abstracts in English
Tanimura, Yoshihiko; Yoshizawa, Michio; Saegusa, Jun; Fujii, Katsutoshi; Shimizu, Shigeru; Yoshida, Makoto; Shibata, Yasunari*; Uritani, Akira*; Kudo, Katsuhisa*
Radiation Protection Dosimetry, 110(1-4), p.85 - 89, 2004/09
Times Cited Count：19 Percentile：74.67(Environmental Sciences)Mono-energetic neutron calibration fields have been developed at the Facility of Radiation Standards (FRS) of JAERI using 4MV Van-de-Graaff (Pelletron) accelerator. The fields of 144 keV, 565 keV and 5.0 MeV neutrons were constructed with estimating neutron energy spectra and establishing the traceability of reference neutron fluence.
Shimizu, Shigeru; Fujii, Katsutoshi; Kajimoto, Yoichi; Kawasaki, Tomokatsu; Yamamoto, Hideaki
Dai-16-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.32 - 35, 2004/02
no abstracts in English
Shimizu, Shigeru; Zhang, Q.; Kajimoto, Yoichi; Kawasaki, Tomokatsu; Fujii, Katsutoshi
JAERI-Tech 2003-095, 52 Pages, 2004/01
JAERI-Tech-2003-095.pdf:2.66MB
The International Standards ISO4037-1 of the International Organization for Standardization widely applied in the world to construct X-ray reference fields for performance tests of radiation measuring instruments. The application of the current JAERI's X-ray reference field constructed in accordance with the Japanese Standards should be limited for domestic purposes becase of the characterization technique different from the International Standards. Therefore,for application to international performance tests, X-ray reference fields in the narrow,wide and high air-kerma series based on the International Standards were established using the medium-hard X-ray generator of the Facility of Radiation Standards(FRS), JAERI. This report presents quality characterization, estimation of X-ray spectra of each dose units of the new FRS's fields,and comparison of the qualities and the X-ray spectra to those of the ISO's. The FRS's qualities show good agreement with ISO's: the reference fields should serve for performance tests for international radiation protection purposes.
Sato, Tatsuhiko; Fujii, Katsutoshi; Murayama, Takashi; Sakamoto, Yukio; Yamaguchi, Yasuhiro; Sato, Yukio*; Soma, Nobuyuki*; Fujisaki, Noboru*; Hara, Satoshi*; Aikawa, Yukio*; et al.
JAERI-Tech 2002-028, 20 Pages, 2002/03
JAERI-Tech-2002-028.pdf:5.01MB
Tokyo Fire Department developed an armored car against radiation accidents. Dose attenuation factors of the radiation shields had been determined by a simple estimation, and a more precise evaluation was required. By request from Tokyo Fire Department, a precise evaluation of the dose attenuation factor was carried out. The evaluation was done by a Monte Carlo radiation transport simulation code MCNP4B. Benchmark experiments using neutron and gamma ray sources were also performed for ensuring the evaluation method. As a result, it was found out that doses of neutron and gamma ray were attenuated to approximately 10% and 25% by the thickest shield, respectively. These values were close to the ones which had already obtained by the simple estimation.
Sc(p,n)Ti reactionTanimura, Yoshihiko; Saegusa, Jun; Fujii, Katsutoshi; Shikaze, Yoshiaki; Tsutsumi, Masahiro
no journal, ,
no abstracts in English
Nakagawa, Masahiro; Nojima, Shun; Fujii, Katsutoshi; Shishido, Nobuhito; Sakai, Toshiya; Umehara, Takashi; Shimizu, Isamu
no journal, ,
no abstracts in English
Arakawa, Yuto; Fujii, Katsutoshi; Mimura, Ryuji; Nakashio, Nobuyuki; Onuma, Isamu; Shishido, Nobuhito; Umehara, Takashi
no journal, ,
no abstracts in English
Kajimoto, Yoichi; Fujii, Katsutoshi; Tanimura, Yoshihiko; Yasu, Katsuji; Yamane, Kenji; Okura, Takehisa; Shimizu, Shigeru
no journal, ,
no abstracts in English
Tanimura, Yoshihiko; Shikaze, Yoshiaki; Fujii, Katsutoshi; Saegusa, Jun; Tsutsumi, Masahiro; Harano, Hideki*; Matsumoto, Tetsuro*; Shimoyama, Tetsuya*
no journal, ,
no abstracts in English
Kikuchi, Masamitsu; Umehara, Takashi; Shishido, Nobuhito; Kuramochi, Akihiko; Fujii, Katsutoshi; Nakajima, Junya
no journal, ,
no abstracts in English
Fujii, Katsutoshi; Takahashi, Teruhiko; Saegusa, Jun; Shishido, Nobuhito; Mochizuki, Kaoru*; Nojima, Shun; Akiyama, Isamu; Shimizu, Isamu
no journal, ,
In NSRR, pulse operation is performed. The correction of counting-loss is needed under the condition that large amount of neutrons have detected in a short period of time. This time, counting-loss of the neutron survey meter(type NSN1) is estimated used for monitoring Burst neutrons at NSRR.
