Production of Spontaneously Fissioning Isomers in Th, U, Np. Pu and Am Isotopes in Reactions Induced By 14.7 Mev Neutrons

The cross-sections for‘ the formation of spontaneously fissioning isomers have been measured in (n, 2n) reactions on 239Pu, 241Pu, 240Am and 242Am and in (n, n') reactions on 230Pu,243Am induced by 14.7 MeV neutrons. Fission fragments were detected by means of a multiwire spark chamber, It was found that the spontaneously fissioning isomers are formed with considerably lower cross-section in (n, n') reactions than in (n, 2n) reaction