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JAEA Reports

Development and performance test of the OSL dosimetry system for environmental monitoring

Yoshitomi, Hiroshi; Futagawa, Kazuo

JAEA-Research 2024-016, 26 Pages, 2025/02

JAEA-Research-2024-016.pdf:2.0MB

In environmental radiation monitoring around nuclear facilities, dose measurements have been implemented by passive dosimetry systems using thermoluminescence dosimeters or radiophotoluminescence dosimeters. Optically stimulated luminescence (OSL) dosimeter, hereinafter called OSLD, is one of the commonly used passive dosimeter for personal dose monitoring and provides highly reliable measurements. However, it has not been utilized for environmental dose monitoring purposes. The OSLD will be a promising dosimeter, which make it possible to conduct cost-effective and reliable environmental dose measurements by utilizing existing resources, such as readers and dosimeters. When considering the application of the OSLD using aluminum oxide ($$alpha$$-Al$$_2$$O$$_3$$:C) for environmental dose monitoring, the following problems should be solved: (1) the lack of a dose calculation algorithm to evaluate air-absorbed dose from OSL signals, and (2) the conformity with JIS Z 4346:2017, which specifies the required performance of passive dosimeters for environmental monitoring, has not been evaluated. Therefore, in this study, a dose calculation algorithm was developed using Monte Carlo simulations, and tests based on JIS Z 4346:2017 were conducted. As a result, it was confirmed that the OSLD meets the performance criteria mentioned in JIS Z 4346:2017. The effective measurement range is from 0.1 mGy to 1 Gy, the range of energy and angle of incidence are from 30 keV to 1.25 MeV and from 0$$^{circ}$$ to $$pm$$60$$^{circ}$$, the temperature and humidity range are from -20$$^{circ}$$C to 40$$^{circ}$$C and from 10% to 90%, which are adequate for environmental dose monitoring.

Journal Articles

Cavity ionization chamber responses in the JAEA and the NMIJ high-energy photon reference fields for radiation protection

Ishii, Junya*; Shimizu, Morihito*; Kato, Masahiro*; Kurosawa, Tadahiro*; Tsuji, Tomoya; Yoshitomi, Hiroshi; Tanimura, Yoshihiko; Watabe, Hiroshi*

Journal of Radiological Protection, 44(3), p.031516_1 - 031516_8, 2024/09

 Times Cited Count:0 Percentile:0.00(Environmental Sciences)

Journal Articles

Establishment of a $$^{241}$$Am gamma calibration field based on international standards and its conversion coefficients

Tsuji, Tomoya; Yoshitomi, Hiroshi; Kowatari, Munehiko*; Tanimura, Yoshihiko

Radiation Protection Dosimetry, 200(15), p.1416 - 1424, 2024/09

 Times Cited Count:0 Percentile:0.00(Environmental Sciences)

Journal Articles

Present and new operational quantities evaluated from photon spectrum measurements at workplaces in the research reactor and accelerator facility at the JAEA

Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Nishino, Sho; Tsuji, Tomoya; Fukami, Tomoyo; Shinozuka, Tomoki; Oishi, Kohei; Ishii, Masato; Takamiya, Kei; Onuki, Takaya; et al.

Radiation Measurements, 176, p.107196_1 - 107196_6, 2024/08

 Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)

The ICRU has proposed to change the definitions of the operational quantities used for the area and individual monitoring for external exposure in the ICRU Report 95. As introducing the new operational quantities into the radiation monitoring may affect the dose assessment results using the present personal dosimeters, it is necessary to characterize the energy spectrum in the workplace and the energy dependency of the dosimeters to be used. In this work the photon spectra were measured using a NaI(Tl) scintillation detector or a LaBr$$_3$$(Ce) scintillation detector at the workplaces in the Japanese Research Reactor No.3 (JRR-3) and the Japan Proton Accelerator Research Complex (J-PARC) at Japan Atomic Energy Agency (JAEA). Then the present and new operational quantities were evaluated using the above mention spectra at the workplaces and compared each other.

Journal Articles

Trends in radiation standard; Current status of secondary standards at JAEA

Tanimura, Yoshihiko; Yoshitomi, Hiroshi

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 66(1), p.42 - 45, 2024/01

no abstracts in English

Journal Articles

Characterization of small radiophotoluminescence dosemeter in terms of $$H_{P}$$(0.07) for extremity dose monitoring of medical personnel

Kowatari, Munehiko*; Yoshitomi, Hiroshi; Nagamoto, Keisuke*; Nakagami, Koichi*; Moritake, Takashi*; Kunugita, Naoki*

Radiation Protection Dosimetry, 199(15-16), p.1807 - 1812, 2023/10

 Times Cited Count:0 Percentile:0.00(Environmental Sciences)

Journal Articles

Report on participation in the 6th Asian and Oceanic Congress on Radiation Protection

Yoshitomi, Hiroshi; Manabe, Kentaro; Ochi, Kotaro; Kono, Takahiko; Sasaki, Michiya*; Yoshida, Hiroko*

Hoken Butsuri (Internet), 58(2), p.105 - 111, 2023/08

This article gives the report on participation in the 6th Asian and Oceanic Congress on Radiation Protection (AOCRP6), which was held in Mumbai, India on between February 7th and 11th, 2023.

Journal Articles

Estimation of inhomogeneous occupational exposure to the lens of the eyes and the extremities of radiation workers in a research accelerator facility

Kowatari, Munehiko*; Kubota, Takumi*; Yoshitomi, Hiroshi; Kunugita, Naoki*

Radiation Protection Dosimetry, 199(11), p.1239 - 1247, 2023/07

 Times Cited Count:0 Percentile:0.00(Environmental Sciences)

Journal Articles

Present status of the FRS/JAEA with newly established accredited JIS testing laboratory

Yoshitomi, Hiroshi

FBNews, (557), p.1 - 5, 2023/05

no abstracts in English

Journal Articles

Establishment of JIS testing laboratory for radiation monitoring instruments

Yoshitomi, Hiroshi

Isotope News, (786), p.26 - 29, 2023/04

no abstracts in English

Journal Articles

Dose measurement precision of an RPLD-based eye lens dosemeter applicable to the medical sector

Kowatari, Munehiko*; Nagamoto, Keisuke*; Nakagami, Koichi*; Yoshitomi, Hiroshi; Moritake, Takashi*; Kunugita, Naoki*

Radiation Protection Dosimetry, 198(17), p.1303 - 1312, 2022/10

 Times Cited Count:2 Percentile:34.71(Environmental Sciences)

Journal Articles

Radiation exposure to the lens of the eye for Japanese nuclear power plant workers

Yokoyama, Sumi*; Tatsuzaki, Hideo*; Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Hirao, Shigekazu*; Aoki, Katsunori; Tachiki, Shuichi*; Ezaki, Iwao*; Hoshi, Katsuya; Tsujimura, Norio

Journal of Radiological Protection, 42(3), p.031504_1 - 031504_17, 2022/09

 Times Cited Count:2 Percentile:34.71(Environmental Sciences)

In Japan, the radiation-dose limit for the lens of the eye was revised in April 2021. Consequently, for workers, the numerical values of the equivalent dose to the lens of the eye are equal to those of the effective dose. Radiation workers, radiation safety officers and licensees must comply with regulations related to radiation protection and optimize protection. The new guidelines on dose monitoring of the lens of the eye developed by the Japan Health Physics Society recommend for the dose to be estimated near the eye for accurate estimation, when the dose to the lens approaches or exceeds the management criteria. However, there is limited information regarding the non-uniform exposure of nuclear power plant workers. In this study, the dose equivalents of high-dose-rate workplaces and the personal doses of 88 workers were estimated at four Japanese commercial nuclear power plant sites (RWR: 3 units and BWR: 3 units) and the dose to the lens of the eye and the exposure situations of the workers were analyzed.

Journal Articles

The Japan Health Physics Society Guideline on Dose Monitoring for the Lens of the Eye

Yokoyama, Sumi*; Tsujimura, Norio; Hashimoto, Makoto; Yoshitomi, Hiroshi; Kato, Masahiro*; Kurosawa, Tadahiro*; Tatsuzaki, Hideo*; Sekiguchi, Hiroshi*; Koguchi, Yasuhiro*; Ono, Koji*; et al.

Journal of Radiation Protection and Research, 47(1), p.1 - 7, 2022/03

Background: In Japan, new regulations that revise the dose limit for the lens of the eye (the lens), operational quantities, and measurement positions for the lens dose were enforced in April 2021. Based on the international safety standards, national guidelines, the results of the Radiation Safety Research Promotion Fund of the Nuclear Regulatory Authority, and other studies, the Working Group of Radiation Protection Standardization Committee, the Japan Health Physics Society (JHPS) developed a guideline for radiation dose monitoring for the lens. Materials and Methods: The Working Group of the JHPS discussed the criteria of non-uniform exposure and the management criteria set to not exceed the dose limit for the lens. Results and Discussion: In July 2020, the JHPS guideline was published. The guideline consists of three parts: main text, explanations, and 26 questions. In the questions, the corresponding answers were prepared, and specific examples were provided to enable similar cases to be addressed. Conclusion: With the development of guideline on radiation dose monitoring of the lens, radiation managers and workers will be able to smoothly comply with revised regulations and optimise radiation protection.

Journal Articles

Development of guidelines on radiation protection for the lens of the eye in Japan

Yokoyama, Sumi*; Iwai, Satoshi*; Tsujimura, Norio; Hashimoto, Makoto; Yoshitomi, Hiroshi; Kato, Masahiro*; Kurosawa, Tadahiro*; Tatsuzaki, Hideo*; Sekiguchi, Hiroshi*; Koguchi, Yasuhiro*; et al.

Proceedings of 15th International Congress of the International Radiation Protection Association (IRPA-15) (Internet), 8 Pages, 2022/00

Journal Articles

Lens dosimetry study in $$^{90}$$Sr+$$^{90}$$Y beta field; Full-face mask respirator shielding and dosemeter positioning

Tsujimura, Norio; Hoshi, Katsuya; Yamazaki, Takumi; Momose, Takumaro; Aoki, Katsunori; Yoshitomi, Hiroshi; Tanimura, Yoshihiko; Yokoyama, Sumi*

KEK Proceedings 2020-5, p.21 - 28, 2020/11

Journal Articles

Measurements of the doses of eye lens for the workers of Fukushima Daiichi Nuclear Power Plant

Yokoyama, Sumi*; Ezaki, Iwao*; Tatsuzaki, Hideo*; Tachiki, Shuichi*; Hirao, Shigekazu*; Aoki, Katsunori; Tanimura, Yoshihiko; Hoshi, Katsuya; Yoshitomi, Hiroshi; Tsujimura, Norio

Radiation Measurements, 138, p.106399_1 - 106399_5, 2020/11

 Times Cited Count:4 Percentile:37.85(Nuclear Science & Technology)

Journal Articles

Background correction method for portable thyroid dose monitor using gamma-ray spectrometer developed at JAEA in high dose rate environment

Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Nishino, Sho; Takahashi, Masa

Radiation Measurements, 137, p.106389_1 - 106389_5, 2020/09

 Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)

A portable thyroid dose monitoring system has been developed at the Japan Atomic Energy Agency (JAEA) to assess the thyroid equivalent dose for workers and members of the public in a high dose rate environment. The background (B.G.) photon correction is required for an accurate measurement in a high dose rate environment at an early stage after a nuclear accident. We developed the B.G. photon correction method using cylindrical PMMA phantoms.

Journal Articles

Prototype test of a portable thyroid dose monitoring system using gamma-ray spectrometers

Nishino, Sho; Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Takahashi, Masa

Radiation Measurements, 134, p.106292_1 - 106292_5, 2020/06

 Times Cited Count:4 Percentile:37.85(Nuclear Science & Technology)

In the situation of a severe nuclear accident, radioiodine monitoring in thyroid should be performed for a large number of people immediately after accident. The portable thyroid dose monitoring system which can be used in a high dose rate condition is in development. In this presentation, the result of performance test using prototype model will be described.

Journal Articles

Eye lens dosimetry for workers at Fukushima Daiichi Nuclear Power Plant, 2; Field study using humanoid phantoms

Tsujimura, Norio; Hoshi, Katsuya; Aoki, Katsunori; Yoshitomi, Hiroshi; Tanimura, Yoshihiko; Yokoyama, Sumi*

Radiation Measurements, 134, p.106305_1 - 106305_5, 2020/06

 Times Cited Count:4 Percentile:37.85(Nuclear Science & Technology)

Journal Articles

Eye lens dosimetry for workers at Fukushima Daiichi Nuclear Power Plant, 1; Laboratory study on the dosemeter position and the shielding effect of full face mask respirators

Hoshi, Katsuya; Yoshitomi, Hiroshi; Aoki, Katsunori; Tanimura, Yoshihiko; Tsujimura, Norio; Yokoyama, Sumi*

Radiation Measurements, 134, p.106304_1 - 106304_5, 2020/06

 Times Cited Count:4 Percentile:37.85(Nuclear Science & Technology)

In FY 2017, the Japanese Nuclear Regulatory Agency (NRA) established the Radiation Safety Research Promotion Fund for funding projects on nuclear safety regulation, and adopted the two-year research project entitled "Study on standard eye lens monitoring, suitable dose management and radiation protection for nuclear and medical workers". The study is a two-phase study: a laboratory study on the eye lens dosemeter's characteristics to photons, and a field study executed at actual workplaces at Fukushima Daiichi Nuclear Power Station. This paper summarizes the results of the first-phase study, which was designed to clarify the eye lens dosemeter positioning and the shielding effect of full face mask respirators used at the station. No marked difference was observed in readings of the dosemeters attached on the different positions on the head phantom. Two types of full face mask respirators provided insignificant shielding effect for photons of 83 keV to 662 keV.

113 (Records 1-20 displayed on this page)