Ternary particles from the reactions 229Th(nth,f) 233U(nth,f) and 239Pu(nth,f)

Energy distributions and yields of ternary particles (TP’s) emitted in the thermal neutron induced fission of 229Th, 233U and 239Pu have been determined. Special emphasis was put on the study of heavy ternary particles. The measurements were performed at the high flux reactor of the Institut Laue-Langevin (ILL). For identification of particles the mass separator Lohengrin and a ΔE-E ionisation chamber were used. In the case of 233U(nth,f) it was possible to detect 25 different TP’s, with 19 of them having never been detected before in this reaction. For 229Th(nth,f) all 17 TP’s that were observed were new. From the reaction 239Pu(nth,f) 21 out of 34 detected TP’s were new. The energy distributions and yields of the TP’s are given. The yields of TP’s as a function of mass number depend on the mass of the decaying compound nucleus. Heavy TP’s are increasingly favored in the decay of heavy mother nuclei.