Mass-yield distributions of fission products from 20, 32, and 45MeV proton-induced fission of ~(232)Th

摘要

The yields of various fission products in the 19.6, 32.2, and 44.8MeV proton-induced fission of ~(232)Th have been determined by recoil catcher and an off-line γ-ray spectrometric technique using the BARC-TIFR Pelletron in India and MC-50 cyclotron in Korea. The mass-yield distributions were obtained from the fission product yield using the charge distribution corrections. The peak-to-valley (P/V) ratio of the present work and that of literature data for ~(232)Th(p, f) and ~(238)U(p, f) were obtained from the mass yield distribution. The present and the existing literature data for 232Th(p, f), 232Th(n, f), and 232Th(γ, f) at various energies were compared with those for ~(238)U(p, f), ~(238)U(n, f), and ~(238)U(γ, f) to examine the probable nuclear structure effect. The role of Th-anomaly on the peak-to-valley ratio in proton-, neutron-, and photon-induced fission of ~(232)Th was discussed with the similar data in ~(238)U. On the other hand, the fine structure in the mass yield distributions of the fissioning systems at various excitation energies has been explained from the point of standard I and II asymmetric mode of fission besides the probable role of even-odd effect, A/Z ratio, and fissility parameter.