Calculation of nuclear level densities for /sup 56/Fe, /sup 59/Co, /sup 60/Ni, /sup 61/Cu, /sup 62/Ni, /sup 63/Cu, and /sup 65/Cu. [Wood-Saxon and Nilsson potentials, spin-cutoff parameters, m value,. pi. , J, partition function inversion]

Journal Article · Thu Jun 01 04:00:00 EDT 1978 · Nucl. Sci. Eng.; (United States)

OSTI ID:7084276

Ford, G P

Nuclear state and level densities as a function of excitation energy, angular momentum, and parity were calculated by a combinatorial method for /sup 56/Fe, /sup 59/Co, /sup 60/Ni, /sup 61/Cu, /sup 62/Ni, /sup 63/Cu, and /sup 65/Cu. Single-particle states for both Woods-Saxon and Nilsson potentials were used. These calculations were done with zero and nonzero pairing energy. State densities as a function of excitation energy were calculated by an approximate inversion of exact partition functions; they agree well with state densities calculated by the combinatorial method. Average excitation energy as a function of temperature was calculated from the partition function for each of the nuclei. Level densities as a function of energy, calculated by the combinatorial method, are compared with measured level densities. The agreement is either good or very good for most, but not all, of the nuclei. No evidence was found that must be interpreted as indicating a failure of the independent-particle model at higher excitation energies. For level density calculations with zero pairing energy, there is a suggestion, but no clear indication, that Woods-Saxon single-particle states are better than Nilsson single-particle states. Calculated and measured spin cutoff parameters are compared for /sup 56/Fe and /sup 61/Cu. Single-particle states for Nilsson-type potentials tend to give higher state and level densities than single-particle states for Woods-Saxon-type potentials. This tendency is not due to the larger number of single-particle states for Nilsson-type potentials, and it can be compensated for by using a nonzero pairing energy. The calculated fraction of negative-parity states is about one-half as expected, but this fraction varies much more than expected from one energy interval to another. The calculated M-value distribution is approximately Gaussian as expected.

• Research Organization: Los Alamos Scientific Lab., NM
• OSTI ID: 7084276
• Journal Information: Nucl. Sci. Eng.; (United States), Journal Name: Nucl. Sci. Eng.; (United States) Vol. 66:3; ISSN NSENA
• Country of Publication: United States
• Language: English

Related Subjects

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR MOMENTUM
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
COBALT 59
COBALT ISOTOPES
COPPER 61
COPPER 63
COPPER 65
COPPER ISOTOPES
ENERGY DEPENDENCE
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
EXCITATION
FUNCTIONS
GAUSS FUNCTION
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
IRON 56
IRON ISOTOPES
ISOTOPES
MATHEMATICAL MODELS
NICKEL 60
NICKEL 62
NICKEL ISOTOPES
NILSSON-MOTTELSON MODEL
NUCLEAR MODELS
NUCLEAR POTENTIAL
NUCLEI
ODD-EVEN NUCLEI
PARITY
PARTICLE PROPERTIES
PARTITION FUNCTIONS
RADIOISOTOPES
SINGLE-PARTICLE MODEL
STABLE ISOTOPES
TEMPERATURE DEPENDENCE
WOODS-SAXON POTENTIAL