Development of LINAC-based neutron source for boron neutron capture therapy in University of Tsukuba

筑波大学におけるホウ素中性子捕捉療法用のリニアックを用いた中性子源の開発

熊田 博明*; 内藤 富士雄*; 長谷川 和男; 小林 仁*; 栗原 俊一*; 高田 健太*; 大西 貴博*; 櫻井 英幸*; 松村 明*; 榮 武二*

Kumada, Hiroaki*; Naito, Fujio*; Hasegawa, Kazuo; Kobayashi, Hitoshi*; Kurihara, Toshikazu*; Takada, Kenta*; Onishi, Takahiro*; Sakurai, Hideyuki*; Matsumura, Akira*; Sakae, Takeji*

Clinical trials of boron neutron capture therapy (BNCT) have been performed using research reactor in the world. Recent progress of technologies for accelerator and for neutron source with the accelerator made it possible to generate a large amount of neutrons required in BNCT treatment by using compact accelerator which can be install to a hospital. University of Tsukuba launched a project of the development of compact accelerator-based neutron source for BNCT. Regarding the accelerator of BNCT neutron source in the project, our project employed RFQ+DTL type linac, and energy of the proton beam is specified to 8 MeV. Regarding neutron target material, we had chosen beryllium. To generate enough neutron intensity by the reaction with 8 MeV proton and beryllium, the linac accelerates a large current of 5 milliampere or more. Regarding target system as a key issue of the development, we have developed a beryllium target system with three-layer structure in order to avoid break of the target in a short period caused by a huge heat load and blistering. The linac-based neutron source for BNCT is almost completed, and we succeeded in the generation of neutrons in 2015. At present, several characteristic measurements are being carried out.