Monte Carlo calculation of the de-excitation of fission fragments of Cf-252(sf) within multimodal random neck rupture model

The multimodal random neck rupture model has been employed to study the energy distribution in nuclear fission. Monte Carlo calculations have been carried out on the de-excitation of fission fragments of Cf-252(sf) using this model. In this study special attention has been paid to the law of conservation of energy. Results for the neutron multiplicities and kinetic energies, average gamma energies are in good agreement with the experimental data. Mass and charge distributions of secondary fission fragments are also well reproduced in the calculations

Ternary particle yields in Cf-249(n(th),f)

An experiment measuring ternary particle yields in Cf-249(n(th),f) was carried out at the high flux reactor of the Institut Laue-Langevin using the Lohengrin recoil mass separator. Parameters of energy distributions were determined for 27 ternary particles up to Mg-30 and their yields were calculated. The yields of 17 further ternary particles were estimated on the basis of the systematics developed. The heaviest particles observed in the experiment are Si-37 and S-37; their possible origin is discussed

Mass and charge distributions in the very asymmetric thermal neutron induced fission of the odd-Z nucleus Am-242m

Yields of light fission products (A = 68, 70-84, 87, 88, 94, 96, 98, 102 and 106-108), their kinetic energies and nuclear charge distributions (A = 71-84, 87 and 88) in the thermal neutron induced fission of the odd-Z nucleus Am-242m(Z = 95) were measured using the mass-separator Lohengrin at the Institute Laue-Langevin in Grenoble (France). The mass yield curve shows a fine structure at A = 70, probably due to shell and/or odd-even effects affecting also the nuclear charge distribution. The analysis of isotopic chain yields gives evidence for a very low excitation energy of the lightest fission fragments observed. A preferential formation of fragments with even Z is found for this odd-Z compound nucleus, Calculated values for the local odd-even effect are comparable with those for the neighbouring even-Z fissile nuclides and increase from 13% to 30% with increasing asymmetry of the mass split (A(L) = 84 to 68 and Z(L) = 35 to 28). The neutron odd-even effect shows a similar but less pronounced behaviour