A Gamma-Ray Counting Apparatus for Evaluating the Fallout Removal Effectiveness of Reverse-Osmosis Water Purification Systems.

摘要

A gamma ray detection system and the procedures for its calibration and use are described. This system was employed during a joint Ballistic Research Laboratory - Mobility Equipment R and D Center test of a reverse-osmosis water purification system's ability to remove dissolved radioisotopes, i.e. fallout, from drinking water. The detector system is able to dose count water samples in the range of activities from a few tens to a few millions of picocuries per liter in a time period of thirty minutes. Its design is based upon scintillation methods and emphasizes counting efficiency, calibration accuracy, and a minimum of sample preparation. In tests on over four hundred samples using the system the activity attenuation of streams of water following reverse-osmosis processing was measured with error of a fraction of one percent. The accuracy of absolute dose level determinations was limited by the errors in the calibration standards at the highest levels and by counting statistics at the lowest levels.