Original version
Journal of Physics, Conference Series. 2015, 580:012048:012048, DOI: http://dx.doi.org/10.1088/1742-6596/580/1/012048
Abstract
The natural log of experimental nuclear level densities at low energy is linear with energy. This can be interpreted in terms of a nearly 1st order phase transition from a superfluid to an ideal gas of quasi particles. The transition temperature coincides with the BCS critical temperature and yields gap parameters in good agreement with the values extracted from even- odd mass differences from rotational states. This converging evidence supports the relevance of the BCS theory to atomic nuclei.