摘要
In sum, 11 (p,xn) related nuclear reactions with 9 target materials, namely 18 O(p,n) 18 F, 15 N(p,n) 15 O, 68 Zn(p,n) 68 Ga, 68 Zn(p,2n) 67 Ga, 69 Ga(p,2n) 68 Ge, 89 Y(p,n) 89 Zr, 100 Mo(p,pn) 99 Mo, 100 Mo(p,2n) 99m Tc, 112 Cd(p,2n) 111 In, 124 Xe(p,2n) 123 Cs and 203 Tl(p,3n) 201 Pb, are involved in the operation of 13 radionuclide-production cyclotrons in Taiwan. The secondary neutrons accompanying these production routes could induce varying degrees of material activation in the cyclotron facility. Accordingly, this study compared the effects of various (p,xn) production routes on the neutron-induced long-lived radioactivity in the concrete walls of a hypothetical cyclotron vault. In addition, an activation-reduction approach involving the addition of a layer of neutron-absorbing material to the surface of inner concrete walls was evaluated.