Persistence of Odd-Even Effect on Nuclear Level Densities at High Excitation Energy
- 1 February 1970
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review C
- Vol. 1 (2), 594-601
- https://doi.org/10.1103/physrevc.1.594
Abstract
Excitation functions and angular distributions for the reaction have been measured between 6.5 and 20.0 MeV for the ground state and the first two excited states in at 0.32 and 0.92 MeV, with spins , , and , respectively. From the angular distributions and the excitation functions, a compound nuclear mechanism is supported for the population of the and levels. At higher bombarding energies there is evidence that a simple pickup mechanism dominates for producing the level. From the fluctuation analysis of the excitation functions for the and levels, the decay width of the compound nucleus was obtained as a function of energy. From the differential cross sections and decay widths, the level density of was deduced at excitation energies between 15 and 23 MeV. The results were combined with low-energy level-density data previously obtained with a magnetic spectrograph. These results, when compared with similar data for even-even , show that the energy shift required to match level densities for odd and even nuclei is the same at low and high excitation energies. The energy dependence of the level density cannot be reproduced over the whole energy range with level-density expressions employing conventional odd-even corrections. The same conclusion is supported by statistical-model calculations of the excitation functions.
Keywords
This publication has 13 references indexed in Scilit:
- Level Densities from Excitation Functions of Isolated LevelsPhysical Review B, 1969
- Nuclear Energy Levels of , , andPhysical Review B, 1967
- Level structure measurements with the (p, α) reaction: (I). Energy levels in 51Mn, 53Mn and 56FeNuclear Physics, 1966
- Nuclear Energy Levels ofandPhysical Review B, 1966
- Effect of experimental resolution on the measured widths of the fluctuation correlation function for nuclear cross sectionsNuclear Physics, 1965
- Determination of Nuclear Level Densities at an Excitation Energy of 20 MeVPhysical Review B, 1965
- The level densities in the compound nuclei Al27 and Ar38 at 20 MeV excitation energyPhysics Letters, 1965
- Theoretical reaction cross sections for alpha particles with an optical modelNuclear Physics, 1962
- Compound nucleus processes in medium mass nucleiNuclear Physics, 1959
- Optical-Model Analyses of Scattering of 4.1-, 7-, and 14-Mev Neutrons by Complex NucleiPhysical Review B, 1958