SILICA SPIKED WITH MIXED GAMMA-RAY STANDARDS FOR USE AS ENVIRONMENTAL REFERENCE MATERIAL

Measurements of radionuclides from environmental samples by gamma-ray spectrometry requires a correction for (self)-attenuation of gamma-rays. The correction can be simplified or avoided by the direct calibration of spectrometers with certified mixed gamma-ray standard matrices with a composition close to that of environmental samples to be assayed. The paper describes the preparation and characterization of a low density (0.27 +/- 0.01)g cm-3 silica matrix spiked with mixed gamma-ray standards. The nuclear homogeneity was computed by a one way variance analysis performed at a 13.8 g subsampling scale. The sampling constant concept is used to replace the rather qualitative usual homogeneity tests.