PNNL

Abstract

Groundwater contamination from 90Sr is an environmental challenge posed to present and former nuclear weapons related sites. Traditional methods of extracting groundwater samples and performing laboratory analyses are expensive, time consuming and induce significant disposal challenges. We present here a prototype counter capable of measuring in-situ 90Sr groundwater concentrations at or above the drinking water limit of 8 pCi/L. The beta-decay of 90Sr, and its daughter 90Y, emits high-energy electrons which create Cerenkov light. Photomultiplier tubes convert the Cerenkov light into an electronic pulse which then undergoes signal processing with standard electronics. Concentrations near the drinking water limit can be measured in a matter of hours if they exist in secular equilibrium. The prototype counter is compact, can be operated by a single person and transmits the results to a central monitoring location.