Intrasource Scattering and Absorption Effects on γ-γ Angular Correlation Measurements

Abstract

Perturbed angular correlation (PAC) is a useful technique for the study of hyperfine interactions. However, its application to solids requires that effects associated with the use of dense sources be taken into consideration. In particular, time — integral PAC measurements, in which the magnitude of the anisotropy is often a measured quantity of interest, must be free of or corrected for directional effects from intrasource interactions of the cascade λ — rays after their emission. These effects are usually negligible in the aqueous solutions commonly used as sources in nuclearspectroscopic applications, but they may become appreciable in extended solid samples of higher density and atomic number. In this paper we describe numerical calculations of the effects of λ — ray scattering and absorption on measured angular correlations. The results of this procedure may be used to choose favourable source configurations in order to minimize these distortions, as well as to correct the data for remaining attenuations.