Thermodynamic Properties of ${}^{56,57}$Fe

Abstract

Nuclear level densities for ${}^{56,57}$Fe have been extracted from the primary $\gamma$-ray spectra using (${}^3$He,${}^3$He${}^{\prime }\gamma$) and (${}^3$He,$\alpha \gamma$) reactions. Nuclear thermodynamic properties for ${}^{56}$Fe and ${}^{57}$Fe are investigated using the experimental level densities. These properties include entropy, Helmholtz free energy, caloric curves, chemical potential, and heat capacity. In particular, the breaking of Cooper pairs and single-quasiparticle entropy are discussed and shown to be important concepts for describing nuclear level density. Microscopic model calculations are performed for level densities of ${}^{56,57}$Fe. The experimental and calculated level densities are compared. The average number of broken Cooper pairs and the parity distribution are extracted as a function of excitation energy for ${}^{56,57}$Fe from the model calculations.

24 pages, 11 figures

References in corpus (5)

• Large-scale prediction of the parity distribution in the nuclear level density and application to astrophysical reaction rates
• Nuclear level densities and gamma-ray strength functions in 44,45Sc
• Thermodynamics of pairing in mesoscopic systems
• Test of nuclear level density inputs for Hauser-Feshbach model calculations
• Spin distribution of nuclear levels using static path approximation with random-phase approximation