Optimization of sample measurement geometries at the Spectrometry Department of SURO v. v. i

Samples of biomass and food are routinely analysed by gamma ray semiconductor spectrometry within the Radiation Monitoring Network (MRS). As standard, a bulk sample is transferred without further treatment into a three litre Marinelli vessel and then measured on an HPGe detector. The compression of samples into this geometry is often difficult (especially in the case of elastic samples such as hay, etc.) and leads to inhomogeneous distribution in the sample volume. Increasing the compression ratio (CR) and improving the resulting sample homogeneity was achieved by pressing with a 60 t hydraulic press in a stainless steel pressing die and then grinding with a dedicated high speed mixer (3500 - 4500 RPM) for two minutes. Increasing the compression ratio (CR) and improving the resulting homogeneity of the sample was achieved by pressing 60t with a hydraulic press in a stainless steel Press Matrix and then grinding with a specialized high - speed blender (3500-4500 RPM) for two minutes. The possibility of cross-contamination of the samples is negligible, rinsing and wiping with alcohol/EDTA is sufficient for stainless steel. (authors)