Gamma rays following ( α, xn) reactions

Abstract

Low energy gamma rays, following the ( α, xn) reaction in thin targets of single isotopes of heavy elements, have been investigated with a scintillation counter technique. When the energy of the alpha particles is selected, such that the preponderance of the reactions occured with the emission of a specific number of neutrons, gamma rays in the cascade through lower excited states of a particular nucleus were observed. In the case of enriched gadolinium targets, gamma rays in the ground state rotational band of Dy 156, Dy 158, Dy 160 and Dy 162 were observed up to those, corresponding to the decay from 10 + rotational states by (α, 4n) and (α, 2n) reactions. Gamma rays from targets of other than even deformed nuclei do not seem to be readily interpretable. It is suggested that the investigation of such gamma rays can be used for spectroscopical studies as well as for the elucidation of the mechanism of reactions, proceeding via a compound nucleus.