Our team aims to enhance the performance of the RI Beam Factory (RIBF) through the comprehensive upgrading, operation, and maintenance of ion sources and the RIKEN heavy-ion linac, RILAC. LAs the most upstream component of the accelerator complex, the ion source is a critical device that determines overall performance. Currently, we operate three ECR ion sources, including two superconducting models, to ensure a stable supply of high-intensity heavy-ion beams to the RIBF. We are also engaged in research and development to achieve even higher beam intensities and greater stability. RILAC was the driving force behind the discovery of element 113, Nihonium. In recent years, with the introduction of the superconducting linear accelerator SRILAC, we have been facilitating the synthesis of new superheavy element and the development of RI production technologies for medical applications. Furthermore, our team is responsible for the maintenance and management of vacuum systems across the entire facility.

Research Subject

The long term high stability of the RILAC operation.
Improvement of high efficiency of the RILAC operation.

List of Selected Publications

T. Nishi, T. Watanabe, T. Adachi, R. Koyama, N. Sakamoto, K. Yamada, O. Kamigaito
"Nondestructive beam envelope measurements using beam position monitors for low-beta heavy ion beams in a superconducting linear accelerator."
Physical Review Accelerators and Beams 28.9 (2025): 092803.
Y. Higurashi, G. Q. Saquilayan, J. Ohnishi, and T. Nagatomo
"Producing intense uranium ion beam for Riken Ri Beam Factory,"
J. Phys.Conf. Ser. 2743, 012051 (2024)
Y. Higurashi, G. Q. Saquilayan, J. Ohnishi, and T. Nagatomo
"Intense vanadium ion beam production for super-heavy element research experiments,"
J. Phys. Conf. Ser. 2743, 012052 (2024).
Y. Morita, T. Nagatomo, and Y. Nakashima,
"Development of an image analysis method for pepperpot emittance monitors,"
J. Phys. Conf. Ser. 2743, 012071 (2024).
G. Q. Saquilayan, T. Nagatomo, Y. Higurashi, J. Ohnishi, T. Nakagawa, and O. Kamigaito
"Beam emittance growth of highly charged ion beams from the RIKEN 28-GHz SC-ECRIS,"
J. Phys. Conf. Ser. 2743, 012081 (2024).
T. Nagatomo, K. Kamakura, Y. Morita, G. Q. Saquilayan, Y. Higurashi, and J. Ohnishi
"Space-charge effects on transverse emittance in the extraction region of the RIKEN 28-GHz ECRIS,"
J. Phys. Conf. Ser. 2743, 012082 (2024).
Y. Morita, T. Nishi, A. Kasagi, K. Kamakura, N. Oka
"Beam intensity prediction for ECR ion source using machine learning"
Proceedings of the 16th International Conference on Heavy Ion Accelerator Technology, East Lansing, MI, USA
T. Nishi
"Development of automatic beam tuning system using Bayesian optimization for high intensity heavy ion beams at RIBF,"
The 8th International Expert Meeting on Challenging Issues of Next-generation High-intensity in-flight Separators, Wako, RIKEN, Japan, January 2025
N. Sakamoto, H. Imao, O. Kamigaito, T. Nagatomo, T. Nishi, K. Ozeki, K. Suda, A. Uchiyama, T. Watanabe, Y. Watanabe, K. Yamada
"5 year operation of RIKEN super-conducting linac"
Proceedings of the 22nd International Conference on RF Superconductivity, Tokyo
M.Tamura, M. Ito, K. Kaneko, K. Oyamada, J. Suzuki, A. Yusa, Y. Higurashi, M. Fujimaki, H. Imao, M. Kidera, T. Nagatomo, T. Nishi, K. Ozeki, N. Sakamoto, K. Suda, A. Uchiyama, T. Watanabe, Y. Watanabe, K. Yamada, H. Yamauchi, O. Kamigaito
"Present status of RILAC"
The 22th Annual Meeting of Particle Accelerator Society of Japan August 6 - August 8, 2025, Tokyo