A comparison of fission fragment measurements made by double-energy and double-velocity techniques

Abstract

Abstract The energies of two coincident fission fragments emitted from spontaneous fission of Cf252 and 25.5-MeV-He4 induced fission of U233 have been measured with semiconductor detectors. The mass distributions and the average total kinetic energy release as a function of the mass ratio obtained from these measurements have been compared in detail with results obtained by the double-velocity time-of-flight technique. For Cf252 this comparison shows that the distributions obtained from double-energy measurements are affected by the emission of several prompt neutrons from the fragments, and that if the results are corrected to account for these neutron effects, good agreement can be obtained between the double-energy and double-velocity measurements. For He4-induced fission of U233, which involves a more highly excited fissioning nucleus, the neutron effects are apparently less serious, so the double-energy results require only relatively simple corrections. The good agreement between results obtained using the two techniques confirms the validity of the calibration procedure for the semiconductor detectors, and suggests that precision experiments can be performed with a semiconductor detector system if corrections are made for the effects of prompt-neutron emission.