ANGULAR DISTRIBUTIONS IN GAMMA–ALPHA REACTIONS IN THE NUCLEI OF NUCLEAR EMULSIONS

Abstract

The angular distribution for alpha particles produced by (γ, α) reactions in the nuclei of nuclear emulsions has been measured. For the reaction 16O(γ, α)12C, in which the 12C nucleus is left in its ground state (J = 0+, T = 0), through an excited state at 12.5 MeV in 16O, the angular distribution is in agreement with a mixture of E1 and E2 interactions, with an E2/E1 intensity ratio of 0.50. For the same reaction, through an excited state at 14.3 MeV in 16O, the angular distribution is best represented by a pure E2 interaction.