Level densities have been extracted from primary gamma spectra for 56,57-Fe and 96,97-Mo nuclei using (3-He,alpha gamma) and (3-He,3-He') reactions on 57-Fe and 97-Mo targets. The level density curves reveal step structures above the pairing gap due to the breaking of nucleon Cooper pairs. The location of the step structures in energy and their shapes arise from the interplay between single-particle energies and seniority-conserving and seniority-non-conserving interactions.
@article{arxiv.nucl-ex/0302028,
title = {Evolution of level density step structures from 56,57-Fe to 96,97-Mo},
author = {A. Schiller and E. Tavukcu and L. A. Bernstein and P. E. Garrett and M. Guttormsen and M. Hjorth-Jensen and C. W. Johnson and G. E. Mitchell and J. Rekstad and S. Siem and A. Voinov and W. Younes},
journal= {arXiv preprint arXiv:nucl-ex/0302028},
year = {2007}
}