Authors: S. Visetpotjanakit and S. Udomsomporn
Publication Type:17th International Congress of Metrology published by EDP Sciences, 2015
Abstract: To determine Sr-90 activity in environmental samples advanced cerenkov counting using liquid scintillation counter has been widely investigated. Separated Y-90 in equilibrium with Sr-90 in a solution can be counted using a Cerenkov measurement without scintillation In addition an equilibriunm Sr-90/Y-90 in a solution can be directly
measured using Y-90 Cerenkov counting. The Sr-90 Cerenkov counting is considered negligible due to its very low counting efficiency. In this work the Cerenkov technique to measure Y-90 counting from a series of Sr-90/Y-90 solution was studied in the two matrices, 16 mL of 1 M HNO3 and 0.1 M HC1. A suitable counting window was found to be in the range of 0-50 keV. Cerenkov counting in the HNOs solution obtained a lower background count rate (2.2 CPM) than those of the HC1 solution (3.32 CPM). Y-90 counting efficiencies of the HNO3 solution (between 56.73 and 64.61%) were slightly lower than those of HCl solution (between 45.19 and 66.34%). However, FOMs of the HNO3 (between 1418 and 1839) were much higher than those of HCl (between 615 and 1326). In this case the HNO3 solution is a better matrix for the Cerenkov counting of Y-90.
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