Simulation of the 2E Technique on neutron multiplicity measurement as a function of fragment mass in spontaneous fission of 252Cf

Abstract

A Monte Carlo simulation algorithm to investigate the measurement of the average prompt neutron multiplicity as a function of pre-neutron mass, ν(A), for fragments from the spontaneous fission of 252Cf is presented. The input data consist of experimental measurements of the kinetic energy and mass distributions obtained by Göök et al., and the values of ν(A) calculated using the FIFRELIN model by Piau et al., νth(A). We analyze the output curve, νsim(A), obtained by simulation of the 2E technique, which should ideally match νth(A). However, we find that νsim(A) exhibits a maximum value at A≈122, close to mass symmetry, while νth(A) has a maximum at A≈118. Additionally, we observe that νsim(A) > νth(A) for A< 90 and A> 169, respectively. We attribute this discrepancy to inaccuracies in the relationship between provisional mass and the pre-neutron mass used in the 2E technique for data processing in each fission event.