Experimental cross sections and mass distribution of fission products of thorium-232 irradiated with protons in energy range 20-140 MeV

摘要

Proton-induced fission of Th-232 was studied in a wide proton energy range 20-140 MeV. A large amount of experimental cross sections for individual and cumulative formation of Th-232 fission products were determined by means of stacked-foil irradiation followed by high-resolution gamma-ray spectrometry. The obtained results were compared with available literature data and theoretical calculations performed with cascade-evaporation-fission model. The fission-product mass distribution in the given proton energy range was described with a three-peak curve representing asymmetric and symmetric fission modes. The fraction of symmetric fission mode increased along with the incident proton energy up to 60-70 MeV reaching a plateau at the value around 0.65.