On the correctness of various approaches in the extraction of the nucleus parameters on example of analysis of the two-step gamma-cascades in 163Dy compound nucleus

TL;DR

This study analyzes two-step gamma-cascade data in 163Dy to validate nuclear models, revealing that level densities and gamma-strength functions depend on the number of excited quasiparticles and vibrations, with implications for model accuracy.

Contribution

It demonstrates the importance of considering quasiparticle and vibration excitations in modeling gamma-decay processes in 163Dy, providing a more accurate description of level densities and gamma-strength functions.

Findings

Level densities are accurately reproduced as sums of quasiparticle excitations.

Changes in gamma-strength functions correlate with the number of excited quasiparticles.

Reliable analysis requires approximating cascade intensity distributions based on primary gamma energies.

Abstract

The model-free analysis of experimental data in the intensities of two-step cascades into 163Dy shows, that the basically special features of the cascade gamma-decay of its compound-state completely correspond to those observed in other nuclei. Thus, the density of the levels in this nucleus with good precision it is reproduced as sum of three, five, seven-quasiparticle excitations with the tenfold, as the minimum, by an increase due to vibration type excitations. The greatest changes in the sum of the radiation strength functions of dipole primary gamma-transitions correlate with a change in the number of excitable quasi-particles. Accordingly, model presentations about the radiation strength functions of larger, than for those existing, accuracy must consider as a quantity of excited quasi-particles, so the presence of the vibration type excitations of all possible types. Moreover, the reliable picture of the studied process can be obtained only from the approximation of the distributions of the intensities of cascades in the function of energies of their primary gamma-transitions.