The irradiation system and dose estimation joint-system for NCT wider application in Kyoto University

The research for neutron capture therapy (NCT) at the Kyoto University Research Reactor (KUR) has been remarkably developing after December 2001. However, the most important subject is the preparations for the KUR provisional shutdown coming in March 2006. In this paper, our present concept and plan are reported about the novel irradiation system and dose estimation system for wider applications of NCT. For the irradiation field, the target nuclear reaction was selected to 7Li(p,n)7Be and the neutron moderator was selected to heavy water. The minimum proton current was about 13 mA for epi-thermal neutron irradiation, and about 9 mA for mix-neutron irradiation. In thermal neutron irradiation, the proton current needed more than 18 mA for 2.5-MeV protons, but only 4 mA for 5.0-MeV protons. For the dose estimation system, we are aiming at the completion of the “dose estimation joint-system”. The data from the on-line measurement systems such as beam monitors and gamma-ray telescopes are fed back to the results for the in-body dose estimation, and then the dose estimations for irradiation field and a living body are jointed. For the beam-monitor system, multi-chamber method was adopted. The surveys were performed for the wall materials and chamber gases.