Nuclear structure of sup 238 Np from neutron-capture and. alpha. -decay measurements

The experimental measurements made in this investigation include secondary {gamma} rays and conversion electrons from thermal neutron capture in {sup 237}Np, primary {gamma} rays from average resonance capture with a 2-keV neutron beam and from resonance capture with thermal neutrons, and {alpha} particles and {gamma} rays, singles and coincidences, from {sup 242}Am{sup {ital m}} {alpha} decay. From these data and those of previous investigations, 69 excited levels in {sup 238}Np with energies {lt}700 keV were identified and, of these, 46 were placed in 13 rotational bands with assigned Nilsson configurations. The results are found to be in good agreement with a semiempirical model calculation. A special feature is the observation of four different {ital K}=0 rotational bands in the low-energy structure of {sup 238}Np. Experimentally determined Gallagher-Moszkowski and Newby matrix elements show reasonable agreement with calculated values.