Parameters of the best approximation for distribution of the reduced neutron widths. The most probable density of neutron resonances in actinides

TL;DR

This paper investigates the distribution of reduced neutron widths in actinides, proposing a method to estimate the most probable density of neutron resonances by approximating widths with multiple distributions, highlighting uncertainties in key nuclear parameters.

Contribution

It introduces a new approach to determine the most probable neutron resonance density using superpositions of distributions, accounting for uncertainties in the Porter-Thomas hypothesis.

Findings

Mean spacing and neutron strength function are uncertain due to experimental and theoretical ambiguities.

Approximation with multiple distributions better fits the measured widths.

Systematic uncertainties dominate the determination of nuclear resonance parameters.

Abstract

In the frameworks of hypothesis of practical constancy of the neutron resonance number in small fixed intervals of neutron energy, their most probable value was determined for nucleus mass region 230<A<244 from approximation of the reduced neutron widths by superposition of two or four independent distributions. This was done under assumption that a set of the measured neutron amplitudes can correspond to one or to superposition of some normal distributions with non-zero average and dispersion differing from reduced neutron width. The main result of the analysis: the mean spacing and neutron strength function values can be determined only with unknown systematical uncertainty whose magnitude is determined by unknown precision of the Porter-Thomas hypothesis correspondence to concrete experimental sets of resonances and unknown experimental mean neutron widths.