The Photodisintegration of Rare Earth Elements

Abstract

The neutron yields from praseodymium, terbium, and holmium have been measured as a function of bremsstrahlung energy, and from these the shapes of the respective cross sections have been deduced. For terbium and holmium, the cross section for photon absorption shows two peaks, in agreement with the predictions of both the hydrodynamic model and the independent particle model of the nuclear photoeffect in non-spherical nuclei. The case of praseodymium was treated as a control experiment, since this nucleus is nearly spherical. Its photon absorption cross section has only one peak, in agreement with expectation for a spherical nucleus. The results are discussed in terms of both the hydrodynamic model and the independent particle model. Values of the deformation parameter are deduced from the photodisintegration data and are compared with values obtained by other methods.