Die energieabhängigkeit der niveaudichte im bereich der kernmassen A = 30–65

Abstract

The available information on the level density at low excitation energy and at the neutron binding energy is combined to determine experimentally both the level density parameter a and the energy shift Δ between the actual groound state and the fictive ground state of the Fermi gas model. Contrary to the widely used shifted Fermi gas model, it is found that the Δ-values for doubly even nuclei are approximately zero, and that the fictive ground states of odd-mass and odd nuclei are negative by about one and two times the pairing energy Δ as determined from odd-even mass differences. The changes introduced into statistical model-calculations by using the back-shifted Fermi gas model instead of the conventionally shifted Fermi gas model are discussed.