Spallation of Bismuth by 380-Mev Protons

Abstract

Bismuth was bombarded by the 380-Mev proton beam of the Nevis Cyclotron to determine production cross sections of various spallation products. Products isolated and assayed were radioactive isotopes of polonium, bismuth, lead, thallium, mercury, gold, and platinum. Each of these elements was separated from the bismuth targets, carefully purified, and counted using a NaI(TlI) crystal scintillation counter having $4\pi$ geometry and ${99}_{-4\mathrm{}}^{+1\mathrm{}}$% efficiency for photons between 20 and 100 kev.