NEUTRON REGULATION APPARATUS AND NEUTRON IRRADIATION APPARATUS

摘要

This neutron irradiation apparatus (100) has: an introduction pipe (1) for introducing a proton beam; a target structure (2) provided at the bottom of the introduction pipe (1); an aluminum fluoride layer (3) disposed at a site that is under the target structure (2) and that is in an irradiation route which neutrons generated from the target structure (2) pass through; and a heavy water layer (4) disposed on the undersurface of the aluminum fluoride layer (3). The thickness of the aluminum fluoride layer (3) is set so as to increase the number of epithermal neutrons. In a case where the number of epithermal neutrons is increased by the aluminum fluoride layer (3) alone, the aluminum fluoride layer (3) must have too large a thickness. In the apparatus (100), therefore, heavy water is disposed. This heavy water can quickly moderate neutrons and thus increase the number of epithermal neutrons without any increase in the thickness. By virtue of a combination of the aluminum fluoride layer (3) and the heavy water layer (4), only fast neutrons can be attenuated to increase the number of epithermal neutrons without any increase in the number of thermal neutrons. Thus, a neutron flux comprising many epithermal neutrons can be obtained.