Correlations of neutron multiplicity and gamma-ray multiplicity with fragment mass and total kinetic energy in spontaneous fission of Cf-252

摘要

The dependence of correlations of neutron multiplicity nu and gamma-ray multiplicity M-gamma in spontaneous fission of Cf-252 on fragment mass A* and total kinetic energy (TKE) have been investigated by employing the ratio of M-gamma/nu and the form of M-gamma (nu). We show for the first time that M-gamma and nu have a complex correlation for heavy fragment masses, while there is a positive dependence of M-gamma for light fragment masses and for near-symmetric mass splits. The ratio M-gamma/nu exhibits strong shell effects for neutron magic number N = 50 and near doubly magic number shell closure at Z = 50 and N = 82. The gamma-ray multiplicity M-gamma has a maximum for TKE = 165-170 MeV. Above 170 MeV M-gamma (TKE) is approximately linear, while it deviates significantly from a linear dependence at lower TKE. The correlation between the average neutron and gamma-ray multiplicities can be partly reproduced by model calculations.