Resumption of JRR-4 and characteristics of the neutron beam for BNCT

Nakamura, Takemi  ; Horiguchi, Hironori; Kishi, Toshiaki ; Motohashi, Jun ; Sasajima, Fumio; Kumada, Hiroaki*

The clinical trials of BNCT have been conducted using JRR-4. The JRR-4 stopped in January 2008, because the graphite reflector was considerably damaged. For this reason, the specifications of graphite reflectors were renewal. All existing graphite reflectors of JRR-4 were changed by new graphite reflectors. The resumption of JRR-4 was carried out with new graphite reflectors in February 2010. We measured the characteristics of neutron beam at the JRR-4 Neutron Beam Facility. A cylindrical water phantom was put the gap for 1cm from the beam port. TLD and gold wire were inserted within the phantom when the phantom was irradiated. The results of the measured thermal neutron flux and the dose in water were compared with MCNP calculations. The calculated results showed the same tendency with the experimental results. These results are proceeding well and will be reported in full paper at July 2010.