Measurements of Nuclear Level Densities and Gamma-Ray Strength Functions   and their Interpretations
  A method to extract primary $\gamma$-ray spectra from particle-$\gamma$ coincidences at excitation energies up to the neutron binding energy is described. From these spectra, the level density and $\gamma$-ray strength function can be determined. From the level density, several thermodynamical quantities are obtained within the microcanonical and canonical ensemble. Also models for the $\gamma$-ray strength function are discussed. 
M. Guttormsen, M. Hjorth-Jensen, J. Rekstad, S. Siem, A. Schiller and   A. Voinov