Establishment of a low-energy X-ray narrow-spectrum series calibration field based on ISO 4037:2019 standard series

Tsuji, Tomoya; Yoshitomi, Hiroshi; Sato, Fuminobu*; Tanimura, Yoshihiko

Radioisotopes, 75(S-01), p.S-004_1 - S-004_6, 2026/04

https://doi.org/10.3769/radioisotopes.S-004

Conversion coefficients and air density correction factors for new operational quantities in monoenergetic photon calibration fields

Tsuji, Tomoya; Yoshitomi, Hiroshi; Nishino, Sho; Sato, Fuminobu*; Tanimura, Yoshihiko

Journal of Radiological Protection, 45(3), p.031519_1 - 031519_8, 2025/09

https://doi.org/10.1088/1361-6498/ae0597

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 (-AlO: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 to 60, the temperature and humidity range are from -20C to 40C and from 10% to 90%, which are adequate for environmental dose monitoring.

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

https://doi.org/10.1088/1361-6498/ad7a07

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

https://doi.org/10.1016/j.radmeas.2024.107196

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(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.

Characterization of small radiophotoluminescence dosemeter in terms of (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

https://doi.org/10.1093/rpd/ncac259

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

https://doi.org/10.1093/rpd/ncad170

Establishment of JIS testing laboratory for radiation monitoring instruments

Yoshitomi, Hiroshi

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

no abstracts in English

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

https://doi.org/10.1088/1361-6498/ac7913

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.

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

https://irpa.net/irpa15/T3.1-O0124.pdf