VARIATION WITH NEUTRON ENERGY OF THE YIELD OF HIGH KINETIC ENERGY FRAGMENTS FROM 233U, 235U and 239Pu

摘要

A fission chamber has been devised which detects with high efficiency those fission events in which the kinetic energy release of the heavier binary fragment is maximal. This detector has been used, in conjunction with a conventional fission detector (whose efficiency is independent of fragment energy), in a study of the relative yield of high kinetic energy fission of 233U, 235U and Pu, induced by low energy neutrons. The variations in the yield of high kinetic energy fragments indicate a qualitative correlation with results of measurements of the relative symmetric fission yield as a function of neutron energy. This corre¬lation, however, suggests that the increased relative symmetric fission is accompanied by an increased relative yield of high kinetic energy fragments, contrary to what has previously been assumed on the basis of current models of the fission process.