| abstract |
To obtain a neutron flux with a large amount of epithermal neutrons. SOLUTION: This neutron irradiation apparatus 100 generates an introduction tube 1 for introducing a proton beam, a target structure 2 provided at the lower end of the introduction tube 1, and a target structure 2 below the target structure 2 The aluminum fluoride layer 3 disposed in the irradiated neutron irradiation path and the heavy water layer 4 laminated under the aluminum fluoride layer 3 are provided. The aluminum fluoride layer 3 is set to a thickness at which epithermal neutrons increase. Since only the aluminum fluoride layer 3 increases in thickness, heavy water is installed. Heavy water quickly decelerates neutrons and can increase epithermal neutrons without increasing thickness. According to the combination of the aluminum fluoride layer 3 and the heavy water layer 4, it is possible to attenuate only fast neutrons to increase epithermal neutrons and not increase thermal neutrons. As a result, a neutron flux with many epithermal neutrons can be obtained. [Selection] Figure 1 |