Perturbations of alpha-gamma angular correlations in the decay of230U and226Th

Perturbations of α-γ angular correlations in the decay of²³⁰U and²²⁶Th, involving the 2⁺ states in²²⁶Th and²²²Ra, have been studied using²³⁰U sources prepared by evaporation of the activity on Al foils, and²²⁶Th sources, prepared by collecting recoil nuclei from a²³⁰U source on Al foils. In vacuum, perturbation coefficients are found to be in agreement with the “hard-core-value” for static magnetic interaction. The perturbations in aluminum are found to be strongly dependent on the method of source preparation.