VI. RNC ACTIVITIESRIKEN Accel. Prog. Rep. 54 (2021)

Safety Management Group
1. Abstract

The RIKEN Nishina Center for Accelerator-Based Science possesses one of the largest accelerator facilities in the world, which
consists of two heavy-ion linear accelerators and five cyclotrons. This is the only site in Japan where uranium ions are accelerated.
The center also has electron accelerators of microtron and synchrotron storage ring. Our function is to keep the radiation level inand around the facility below the allowable limit and to keep the exposure of workers as low as reasonably achievable. We are also
involved in the safety management of the Radioisotope Center, where many types of experiments are performed with sealed andunsealed radioisotopes.

2. Major Research Subjects(1) Safety management at radiation facilities of Nishina Center for Accelerator-Based Science(2) Safety management at Radioisotope Center(3) Radiation shielding design and development of accelerator safety systems

3. Summary of Research Activity

Our most important task is to keep the personnel exposure as low as reasonably achievable, and to prevent an accident. Therefore,
we daily patrol the facility, measure the ambient dose rates, maintain the survey meters, shield doors and facilities of exhaust airand wastewater, replenish the protective supplies, and manage the radioactive waste. Advice, supervision and assistance at major
accelerator maintenance works are also our task.
Minor improvements of the radiation safety systems were also done. The old type of computer system unit for the radiation
monitoring system and the old UPS for radiation management system of the RIBF building were replaced. The old exhaust equipmentof hotlabo exhaust system in Nishina building was also replaced.

Members
Director
Kanenobu TANAKA
Research/Technical Scientists
Rieko HIGURASHI (Technical Scientist)

Hisao SAKAMOTO (Technical Scientist)

Expert Technician
Atsuko AKASHIO
Technical Staﬀ I
Hiroki MUKAI
Junior Research Associate
Kenta SUGIHARA
Visiting Scientists
Masayuki HAGIWARA (KEK)
Noriaki NAKAO (Shimizu Corporation)
Toshiya SANAMI (KEK)

Nobuhiro SHIGYO (Kyushu Univ.)
Hiroshi YASHIMA (Kyoto Univ.)

Part-time Workers
Kimie IGARASHI (Administrative Part-time Worker I)
Satomi IIZUKA (Administrative Part-time Worker II)

Yukiko SHIODA (Administrative Part-time Worker II)
Naoko USUDATE (Administrative Part-time Worker II)

Temporary Staﬃng
Ryuji SUZUKI
Assistant
Tomomi OKAYASU

List of Publications & Presentations
Publications[Original Papers]
K. Sugihara, N. Shigyo, E. Lee, T. Sanami, and K. Tanaka, “Measurement of thick target neutron yields from 7 MeV/u α incidence on209Bi,” Nucl. Instrum. Method Phys. Res. B 470 (2020).

[Proceedings]
K. Sugihara, N. Shigyo, A. Akashio, and K. Tanaka, “Measurement of neutron energy spectra of 345 MeV/u 238 U incidence on a coppertarget,” JAEA-Conf 2020-001, 143–147.

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Presentations[International Conferences/Workshops]
K. Sugihara (poster), Y. Ikeda, T. Kobayashi, K. Fujita, N. Shigyo, K. Tanaka, and Y. Otake, “Study on characteristics of neutron andγ-ray fields at compact neutron source RANS-II facility by simulation by the PHITS code,” 2020 Symposium on Nuclear Data, RIKEN
Wako Campus, November 26–27, 2020.

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