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Journal Articles

Quantitative estimation of exposure inhomogeneity in terms of eye lens and extremity monitoring for radiation workers in the nuclear industry

Yoshitomi, Hiroshi; Kowatari, Munehiko; Hagiwara, Masayuki*; Nagaguro, Seiji*; Nakamura, Hajime*

Radiation Protection Dosimetry, 184(2), p.179 - 188, 2019/08

 Times Cited Count:0 Percentile:100(Environmental Sciences)

Journal Articles

Dataset of TLD badge response and hair activation for criticality accident neutron dosimetry

Tsujimura, Norio; Takahashi, Fumiaki; Takada, Chie

Progress in Nuclear Science and Technology (Internet), 6, p.148 - 151, 2019/01

Journal Articles

Assessment of equivalent dose of the lens of the eyes and the extremities to workers under nonhomogeneous exposure situation in nuclear and accelerator facilities by means of measurements using a phantom coupled with Monte Carlo simulation

Yoshitomi, Hiroshi; Hagiwara, Masayuki*; Kowatari, Munehiko; Nishino, Sho; Sanami, Toshiya*; Iwase, Hiroshi*

Proceedings of 14th International Congress of the International Radiation Protection Association (IRPA-14), Vol.3 (Internet), p.1188 - 1195, 2017/11

The equivalent doses to the lens of the eye and extremities for radiation workers should be assessed properly to ensure that the dose limits are not exceeded. Recently, the following two issues has pressed demand on more appropriate evaluation of the equivalent doses of the lens of the eye and extremity. One is the new occupational dose limit for the lens of the eye the ICRP recommended. The other is growing demand on handling of highly activated materials in the maintenance works of an accelerator and contaminated materials during the decommissioning works of nuclear facility, which increases the potential exposure risk to the extremities to a wider variety of radio-nuclides. Since the points to be assessed for the exposures to the lens of the eye and the extremities are apart from the trunk, the homogeneity of the radiation fields would be significantly impact on the assessment of these equivalent doses. However, there has been no sufficient and available method to identify the nonhomogeneous situations systematically in terms of the eye lens or extremity monitoring. The goal of this study is to provide the framework to identify the nonhomogeneous exposure situations. In order to fulfil this purpose, newly proposed indices to represent the homogeneity were calculated by Monte Carlo simulation incorporated with mathematical phantom, verifying the benchmark measurements. Important parameters that significantly impact on these indices were also shown from the various trials of calculations of homogeneity indices.

Journal Articles

Uncertainty in predictions of the ambient dose equivalent rates for 30 years following the Fukushima Daiichi Nuclear Power Plant accident

Kinase, Sakae; Takahashi, Tomoyuki*; Sato, Satoshi; Yamamoto, Hideaki; Saito, Kimiaki

Proceedings of 17th NSFS Conference (Internet), p.27 - 33, 2016/02

Journal Articles

Numerical analysis of organ doses delivered during computed tomography examinations using Japanese adult phantoms with the WAZA-ARI dosimetry system

Takahashi, Fumiaki; Sato, Kaoru; Endo, Akira; Ono, Koji*; Ban, Nobuhiko*; Hasegawa, Takayuki*; Katsunuma, Yasushi*; Yoshitake, Takayasu*; Kai, Michiaki*

Health Physics, 109(2), p.104 - 112, 2015/08

 Times Cited Count:4 Percentile:51.6(Environmental Sciences)

A dosimetry system, named WAZA-ARI, is developed to assess accurately radiation doses to persons from Computed Tomography (CT) examination patients in Japan. Organ doses were prepared to application to dose calculations in WAZA-ARI by numerical analyses using average adult Japanese human models with the Particle and Heavy Ion Transport code System (PHITS). Experimental studies clarified the radiation configuration on the table for some multi-detector row CT (MDCT) devices. Then, a source model in PHITS could specifically take into account for emissions of X-ray in each MDCT device based on the experiment results. Numerical analyses with PHITS revealed a concordance of organ doses with human body size. The organ doses by the JM phantoms were compared with data obtained using previously developed systems. In addition, the dose calculation in WAZA-ARI were verified with previously reported results by realistic NUBAS phantoms and radiation dose measurement using a physical Japanese model. The results implied that analyses using the Japanese phantoms and PHITS including source models can appropriately give organ dose data with consideration of the MDCT device and physiques of typical Japanese adults.

Journal Articles

Shielding design of the ITER NBI Duct for nuclear and bremsstrahlung radiation

Sato, Satoshi; Iida, Hiromasa; Yamauchi, Michinori*; Nishitani, Takeo

Radiation Protection Dosimetry, 116(1-4), p.28 - 31, 2005/12

 Times Cited Count:2 Percentile:80.41(Environmental Sciences)

no abstracts in English

Journal Articles

Development of computational dosimetry system "JCDS" for neutron capture therapy

Kumada, Hiroaki; Yamamoto, Kazuyoshi; Matsumura, Akira*; Nakagawa, Yoshinobu*

Hoshasen, 31(4), p.287 - 297, 2005/10

no abstracts in English

JAEA Reports

Shielding design for target trolley for a spallation neutron source in the J-PARC project

Tamura, Masaya; Maekawa, Fujio; Harada, Masahide; Haga, Katsuhiro; Konno, Chikara

JAERI-Tech 2005-020, 58 Pages, 2005/03

JAERI-Tech-2005-020.pdf:18.82MB

no abstracts in English

Journal Articles

Dogleg duct streaming experiment with 14 MeV neutron source

Morimoto, Yuichi*; Ochiai, Kentaro; Nishio, Takashi*; Wada, Masayuki*; Yamauchi, Michinori*; Nishitani, Takeo

Journal of Nuclear Science and Technology, 41(Suppl.4), p.42 - 45, 2004/03

no abstracts in English

Journal Articles

Shutdown dose evaluation experiment for ITER

Morimoto, Yuichi*; Ochiai, Kentaro; Sato, Satoshi; Hori, Junichi; Yamauchi, Michinori*; Nishitani, Takeo

Fusion Engineering and Design, 69(1-4), p.643 - 648, 2003/09

 Times Cited Count:3 Percentile:72.51

no abstracts in English

JAEA Reports

Evaluation of energy response of neutron rem monitor applied to high-energy accelerator facilities

Nakane, Yoshihiro; Harada, Yasunori; Sakamoto, Yukio; Oguri, Tomomi*; Yoshizawa, Michio; Takahashi, Fumiaki; Ishikura, Takeshi*; Fujimoto, Toshiaki*; Tanaka, Susumu; Sasamoto, Nobuo

JAERI-Tech 2003-011, 37 Pages, 2003/03

JAERI-Tech-2003-011.pdf:1.73MB

no abstracts in English

JAEA Reports

3-dimensional shielding design for a spallation neutron source facility in the high-intensity proton accelerator project

Tamura, Masaya; Maekawa, Fujio

JAERI-Tech 2003-010, 54 Pages, 2003/03

JAERI-Tech-2003-010.pdf:7.97MB

Evaluation of shielding performance for a spallation neutron source facility in the J-PARC Project is important from a viewpoint of radiation safety and optimization of arrangement of components. This report describes evaluated results for the shielding performance with modeling three-dimensionally whole structural components including gaps between them in detail. A Monte Carlo calculation method with MCNPX2.2.6 code and LA-150 library was adopted. Streaming and void effects, optimization of shield for cost reduction and optimization of arrangement of structures such as shutters were investigated. Horizontal required shield thicknesses were ranged from about 6.5m to 7.5m as a function of neutron beam line angles. A shutter mechanism for a horizontal neutron reflectometer that was directed downward was devised, and it was shown that the shielding performance of the shutter was acceptable. An optimal biological shield configuration was finally determined according to the calculated results.

Journal Articles

Conversion from tooth enamel dose to organ doses for ESR dosimetry

Takahashi, Fumiaki; Yamaguchi, Yasuhiro

Radiation Risk Assessment Workshop Proceedings, p.71 - 78, 2003/00

Conversion from tooth enamel dose to organ doses against external photon exposure were studied in order to develop a method that can retrospectively estimate organ doses by the Electron Spin Resonance (ESR) dosimetry using tooth samples. Monte Carlo calculations using EGS4 code were performed to obtain dose to tooth enamel and organ doses by using a modified MIRD-type phantom. The Electron Spin Resonance (ESR) dosimetry using tooth samples and dose measurements using thermo-luminescence dosimeters (TLDs) were also carried out to examine dose to teeth region with a realistic physical phantom. A Voxel-type phantom was constructed from CT images of the physical phantom. Monte Carlo calculations with the Voxel-type phantom were performed to verify the results of the experiments and enamel doses calculated by use of the modified MIRD-type phantom. The obtained data are to be useful for the retrospective assessment of individual dose in past exposure events by the ESR dosimetry with tooth enamel.

Journal Articles

Conversion from tooth enamel dose to organ doses for the electron spin resonance dosimetry

Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Iwasaki, Midori*; Miyazawa, Chuzo*; Hamada, Tatsuji*; Saito, Kimiaki

Journal of Nuclear Science and Technology, 39(9), p.964 - 971, 2002/09

 Times Cited Count:6 Percentile:57.47(Nuclear Science & Technology)

Conversion from tooth enamel dose to organ doses was analyzed to establish a method of retrospective individual dose assessment against external photon exposure by the Electron Spin Resonance (ESR) dosimetry. Dose to tooth enamel was obtained by Monte Carlo calculations using a modified MIRD-type phantom. The calculated tooth enamel doses were verified by measurements with thermo-luminescence dosimeters inserted in a physical head phantom. Energy and angular dependences of tooth enamel dose were compared with those of other organ doses. Additional Monte Carlo calculations were performed to study the effects of human model on the tooth enamel dose with a voxel-type phantom, which was based on CT images of the physical phantom. The data derived with the modified MIRD-type phantom were applied to convert from tooth enamel dose to organ doses against external photon exposure in a hypothesized field, where scattered radiations were taken into account. The results indicated that energy distribution of photons incident to a human body should be required to evaluate precisely individual dose by the ESR dosimetry using teeth.

Journal Articles

Analysis of absorbed dose to tooth enamel for ESR dosimetry

Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Saito, Kimiaki; Iwasaki, Midori*; Miyazawa, Chuzo*; Hamada, Tatsuji*; Funabiki, Jun*

Journal of Nuclear Science and Technology, 39(Suppl.2), p.1314 - 1317, 2002/08

An analysis of dose to tooth enamel was carried out to develop a method that can predict the organdose and effective dose by the Electron Spin Resonance (ESR) dosimetry using teeth for external photon exposure. Absorbed dose to tooth enamel were obtained with Monte Carlo calculations using EGS4 code with a mathematical human model, which has a newly defined teeth-part. Experiments were also carried out to investigate the dose at the tooth area with a physical head phantom. The calculated doses to tooth enamel were, however, less than the measured doses with the TLDs for the case of photon incidence from the back of a human body. Then, a computational human model, called a “Voxel (Volume-pixel) type" phantom was constructed based upon a computed topography (CT) image of the physical head phantom used in the experiments.The additional Monte Carlo calculations were performed to verify the results in the experiments with the EGS4 in conjunction with user's code UCPIXEL and the Voxel type phantom.

Journal Articles

Analysis of HTTR's core with Monte Carlo code MVP

Fujimoto, Nozomu; Nojiri, Naoki; Yamashita, Kiyonobu; Shimakawa, Satoshi; Ando, Hiroei; Mori, Takamasa

Nippon Genshiryoku Gakkai Monte Karuro Ho Ni Yoru Ryushi Shimyureshon No Genjo To Kadai, p.201 - 210, 2002/01

no abstracts in English

Journal Articles

Relations between tooth enamel dose and organ doses for the Electron Spin Resonance dosimetry against external photon exposure

Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Iwasaki, Midori*; Miyazawa, Chuzo*; Hamada, Tatsuji*

Radiation Protection Dosimetry, 95(2), p.101 - 108, 2001/09

 Times Cited Count:26 Percentile:12.56(Environmental Sciences)

An analysis of doses to tooth enamel and to organs was carried out to develop a method that can predict the organ doses and the effective dose by the Electron Spin Resonance (ESR) dosimetry using tooth samples for external photon exposure. Absorbed dose to tooth enamel and organ doses were obtained by Monte Carlo calculations using EGS4 code in combination with a mathematical human model with a newly defined teeth-part. The calculations gave quantitative relations between tooth enamel dose and organ doses for some cases of external photon exposure. It was also found that tooth enamel dose depends more significantly on energy of incident photons than the other organ dose or the effective dose. The obtained data are to be useful for the assessment of individual dose in past exposure events by the ESR dosimetry with tooth enamel.

JAEA Reports

Report of "Monte Carlo Calculation Summer Seminar"

Sakurai, Kiyoshi; Kume, Etsuo; Yatabe, Shigeru*; Maekawa, Fujio; Yamamoto, Toshihiro; Nagaya, Yasunobu; Mori, Takamasa; Ueki, Kotaro*; Naito, Yoshitaka*

JAERI-Review 2000-034, 133 Pages, 2001/02

JAERI-Review-2000-034.pdf:7.69MB

no abstracts in English

Journal Articles

Analysis of dose in teeth for estimation of effective dose by the electron spin resonance (ESR) dosimetry using dental enamels

Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Saito, Kimiaki; Iwasaki, Midori*; Miyazawa, Chuzo*; Hamada, Tatsuji*

KEK Proceedings 2000-20, p.48 - 55, 2000/12

no abstracts in English

Journal Articles

Measurement and analysis of neutron and $$gamma$$-ray doses on criticality accidents of low-enriched uranyl nitrate solution using tissue-equivalent dosimeters at the TRACY facility

Sono, Hiroki; Yanagisawa, Hiroshi; Ono, Akio; Kojima, Takuji; Miyoshi, Yoshinori; Soramasu, Noboru*

Proceedings of the ANS International Topical Meeting on Advances in Reactor Physics and Mathematics and Computation into the Next Millennium (PHYSOR2000) (CD-ROM), 9 Pages, 2000/05

no abstracts in English

55 (Records 1-20 displayed on this page)