MASS AND ENERGY DISTRIBUTION OF FISSION FRAGMENTS FROM THEIR RANGES IN SOLID STATE DETECTORS

A method is given to take mass and kinetic energy distribution of fission fragments with solid state detectors. The target material is evaporated on two detector foils (acetylcelluloid in the present experiment) and the foils arranged to form a sandwich during irradiation and scanning under the microscope. This allows to measure simultaneously the ranges of the two correlated fragments in binary fission. An empirical range-energy relationship for heavy ions in several stopping materials has been set up. Using this relationship and - apart from minor corrections - mass and momentum conservation, the mass and energy of the fission fragments are calculated event by event. The results of an experiment on 238U(n,f) induced by 15.3 and 4.65 MeV neutrons are compared with the findings obtained by other techniques. From the comparison range straggling data are found. © 1968.