Preparation of large-area sources with uniform layers for the spectrometry of alpha-emitting nuclides

Abstract

A procedure for the preparation of large-area sources with uniform layers for α-spectrometry for the large-area grid ionization chamber has been developed. It is based on the direct evaporation of a sample solution in the counting dish in the presence of an excess of a sublimable chemical compound like ammonium nitrate. In the course of evaporation this excess compound precipitates and thus avoids the formation of clusters during the further evaporation process. After dryness, the excess compound is removed from the source by sublimation. Samarium nitrate is added as an internal standard and the alpha-activity of the isotope¹⁴⁷Sm is chosen to measure the counting efficiency due to self-absorption. Examples are presented of the application of large-area sources for α-spectrometry for the large-area grid ionization chamber.