Spontaneous fission of 246Fm

TL;DR

This study measured the neutron yields, half-life, and fission branching ratio of the isotope 246Fm using advanced detection methods, providing new experimental data and comparing it with theoretical models.

Contribution

First experimental measurement of neutron yields, multiplicity distribution, and half-life of 246Fm using SHELS separator and advanced analysis techniques.

Findings

Neutron yield per fission: 3.79 ± 0.30

Fission branching ratio: 0.061 ± 0.005

Half-life: 1.50 +0.08/-0.07 seconds

Abstract

An experiment on the study of the $^{246}$Fm spontaneous fission was conducted using the SHELS separator. The isotope was synthesized in the complete fusion reaction of $^{40}$Ar beam ions and $^{208}$Pb target nuclei. The neutron yields of $^{246}$Fm spontaneous fission ($\overline{\nu} = 3.79\pm0.30$, $\sigma^{2}_{\nu} = 2.1$) were obtained using the SFiNx detector system. The multiplicity distribution of emitted prompt neutrons was restored using the Tikhonov method of statistical regularisation ($\overline{\nu}_{r} = 3.79\pm0.20$, $\sigma^{2}_{\nu r} = 2.8$). The spontaneous fission branching ratio ($b_{SF} = 0.061\pm0.005$) and the half-life ($T_{1/2} = 1.50^{+0.08}_{-0.07}$ s) of the isotope were determined. The experimental data were compared with scission point model predictions. Excellent convergence was observed in the average number of neutrons per spontaneous fission process. However, the forms of the experimental and model prompt neutron multiplicity distributions differ significantly.