Comparison of the ruggedized ZnS(Ag)/EPOXY and mylar-based alpha detectors for wastewater streams

摘要

A low-level alpha radiation sensor has been designed and developed at Oak Ridge National Laboratory (ORNL) for monitoring process wastewater streams at the Westinghouse Savannah River Site (SRS). This new Ruggedized Contamination Detector (RCD) is intended to replace the fragile, mylar-based scintillators and has improved sensitivity and reliability for detecting alpha contamination. The unique entrance window invented for this sensor has considerably less mass per unit area than conventional Mylar windows currently used in wastewater streams. The thin layer deposited between the radiation detection medium and potentially contaminated wastewater makes it much easier to detect short-range alpha particles. Compared to the conventional Mylar-based detectors, the new design allows for eight times the number of (sup 238)U alphas to penetrate the entrance window and reach the scintillation material and eliminates the need for routine replacement of the Mylar entrance window.