Induced radioactivity in CU targets produced by high-energy heavy ions and the corresponding estimated photon dose rates.

Abstract

Irradiation experiments were performed at the Heavy Ion Medical Accelerator in Chiba (HIMAC) facility, National Institute of Radiological Sciences. The radioactive spallation products in a thick Cu target were obtained for Ar(230, 400 MeV per nucleon), Si(800 MeV per nucleon), Ne(100, 230, 400 MeV per nucleon), C(100, 230, 400 MeV per nucleon), He(100, 230 MeV per nucleon), p(100, 230 MeV) ions. The gamma-ray spectra from irradiated Cu samples inserted into the composite Cu target were measured with a high-purity germanium (HPGe) detector. From the gamma-ray spectra, we obtained the spatial distribution of radioactive yields of spallation products of 40 nuclides in the Cu sample in the Cu target. From the spatial distribution of radioactive yields, we estimated the residual activity and photon dose induced in the Cu target. The residual activity and photon dose become larger with the increase in projectile energy per nucleon and the range of the projectile beam for the same projectile energy per nucleon.