Ⅵ. ORGANIZATION AND ACTIVITIES OF RNC

RIKEN Accel. Prog. Rep. 56 (2023)

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)
(2)
(3)
(4)

Safety management at radiation facilities of Nishina Center for Accelerator-Based Science
Safety management at Radioisotope Center
Radiation shielding design and development of accelerator safety system
Obtaining permissions for changes accelerators and use of radioisotopes

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 air
and wastewater, replenish the protective supplies, and manage the radioactive waste. Advice, supervision and assistance at major
accelerator maintenance works are also our task.
Permissions from Nuclear Regulation Authority of Japan for the Radioisotope Production beamline and additional quantity of
unsealed radioisotope astatine-211 was obtained. Safety measures were conducted in the Radioisotope Experimental building owing
to the increased use of alpha-emitting nuclides. Measures for the Covid-19 infection in Nishina center were also conducted. A ﬁredrill by a small group of emergency response personnel assuming Saturday, Sunday and nighttime hours were carried out with thegeneral aﬀairs section in RIKEN.

Members
Director
Kanenobu TANAKA
Technical Scientists
Rieko HIGURASHI
Hisao SAKAMOTO

Hiroki Mukai

Expert Technician
Atsuko AKASHIO
Visiting Scientists
Toshiya SANAMI (KEK)
Kenta SUGIHARA (KEK)
Hiroshi YASHIMA (Kyoto Univ.)

Nobuhiro SHIGYO (Kyushu Univ.)
Eunji LEE (KEK)

Administrative Part-time Workers
Kimie IGARASHI
Satomi IIZUKA
Miyabi MURATA

Naoko USUDATE
Tokie KUDO

Temporary Staﬃng
Ryuji SUZUKI
Assistant
Tomomi OKAYASU

List of Publications & Presentations
Publications[Original Papers]
K. Sugihara, N. Shigyo, A. Akashio, and K. Tanaka, “Measurement of neutron energy spectra of 345 MeV/nucleon 238 U incidence on acopper target,” Nucl. Instrum. Methods Phys. Res. B 512, 102 (2022).
K. Sugihara, N. Shigyo, E. Lee, T. Sanami, and K. Tanaka, “Measurement of thick target neutron yields from 7 MeV/nucleon α incidence
on 209 Bi,” Nucl. Instrum. Methods Phys. Res. B 470, 15 (2020).

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RIKEN Accel. Prog. Rep. 56 (2023)

Presentations[International Conferences/Workshops]
K. Tanaka (plenary), “Resent ﬁre protection status at RIKEN RIBF cyclotron facility,” International Technical Safety Forum (ITSF2022),
Meyrin, Switzerland, October 24–28, 2022.
K. Sugihara (plenary), N. Shigyo, A. Akashio, and K. Tanaka, “Measurement of neutron production yields of 345 MeV/nucleon 238 U +Cu with a time-of-ﬂight method,” 15th workshop on Shielding aspects of Accelerators, Tagets, and Irradiation Facilties (SATIF-15),
Michigan, USA, September 20–23, 2022.

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