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All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Nuclear Data Sheets for A=155

This work represents an update of the previous evaluation of the nuclear data on the A=155 nuclides (2005Re01). The experimental data from reaction and decay studies leading to the following nuclides have been reviewed: {sup 155}La, {sup 155}Ce, {sup 155}Pr, {sup 155}Nd, {sup 155}Pm, {sup 155}Sm, {sup 155}Eu, {sup 155}Gd, {sup 155}Tb, {sup 155}Dy, {sup 155}Ho, {sup 155}Er, {sup 155}Tm, {sup 155}Yb, {sup 155}Lu, {sup 155}Hf, and {sup 155}Ta. These data are presented, together with the adopted level schemes and their properties.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

State densities of heavy nuclei in the static-path plus random-phase approximation

We report that nuclear state densities are important inputs to statistical models of compound-nucleus reactions. State densities are often calculated with self-consistent mean-field approximations that do not include important correlations and must be augmented with empirical collective enhancement factors. Here, we benchmark the static-path plus random-phase approximation (SPA + RPA) to the state density in a chain of samarium isotopes 148–155 Sm against exact results (up to statistical errors) obtained with the shell-model Monte Carlo (SMMC) method. The SPA + RPA method incorporates all static fluctuations beyond the mean field together with small-amplitude quantal fluctuations around each static fluctuation. Using a pairing plus quadrupole interaction, we show that the SPA + RPA state densities agree well with the exact SMMC densities for both the even- and odd-mass isotopes. For the even-mass isotopes, we also compare our results with mean-field state densities calculated with the finite-temperature Hartree-Fock-Bogoliubov (HFB) approximation. We find that the SPA + RPA repairs the deficiencies of the mean-field approximation associated with broken rotational symmetry in deformed nuclei and with the violation of particle-number conservation in the pairing condensate. In particular, in deformed nuclei the SPA + RPA reproduces the rotational enhancement of the state density relative to the mean-field state density.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗