A RELIABLE AND ACCURATE PROCEDURE FOR PREPARING LOW-ACTIVITY EFFICIENCY CALIBRATION STANDARDS FOR GERMANIUM GAMMA-RAY SPECTROMETERS

An empirical procedure is described which is readily capable of producing reliable and accurate efficiency calibration sources of low activity for high-resolution gamma-ray spectrometers. Known activities of a multi-isotopic solution are adsorbed onto a mixture of cation and anion-exchange resins and chromatographic-grade cellulose. The dried powder that results can be mixed with any desired solid natural matrix material to produce a homogeneous, extended geometry, efficiency calibration source. Results are presented which enable the method to be critically evaluated.