Ternary fission in He-4+U-238 interaction

Compound nucleus fission accompanied by the emission of light charged parti cles (ternary fission) has been studied in the He-4(24 MeV) + U-238 interac tion. Fission fragments have been recorded by the time-of-flight method by using a two-arm spectrometer based on multiwire parallel-plate avalanche co unters. Light charged particles have been detected by two telescopes, the D elta E and E sections of each telescope being, respectively, a gaseous prop ortional counter and an array of PIN diodes. The events of ternary fission have been measured as coincidences between pulses in the recording channels of fission fragments and light charged particles. The probabilities of ter nary and binary fission has been found to be in proportion 1.88(19) x 10(-3 ) : 1. The mechanisms responsible for the emission of light charged particl es in heavy-nucleus fission and the excitation-energy dependence of the pro bability of this process are discussed.