Improving the recovery of polonium analysis in sediment samples by alpha particle spectrometry

Abstract

At the ANSTO low level radioanalytical facility, sediment samples for lead-210 dating are analysed for polonium-210 and radium-226 activities by alpha particle spectrometry. To improve the efficiency of sample digestion, a block digester was acquired for digesting sediment and other environmental samples. A new hot plate stirrer was also acquired and used in the isolation of polonium via autodeposition onto silvers disks. The change in the digestion and auto-deposition steps resulted in improved polonium recoveries from 50-60% to 80-90%. The ability to control the acid digestion temperature at 90°C and between 70°C to 80°C during autodeposition improved the polonium recoveries.