CALIBRATION OF A FISSION GAS MONITOR.

Abstract

Abstract-A method for calibrating beta-sensitive gas-monitoring equipment is presented which avoids precise mixing of concentrated active gases with diluent air This method depends upon ntutron activation of the argon in P- 10 proportional counting gas Ld passage ofthe active gas suevely through the monitor chamber and a proportional counter chamber. The latter serves for the determination of specific activity of the monitor gas. The method is satisfactory for specific activities corresponding approximately to maximum permissible concentration (MPC) levels. INTRODUCTION IN MONITORING for gross airborne activities, the separate determination of particulate and gaseous activities is frequently desirable. The particulates can be determined by conventional filter techniques, which in conjunction with suitable detectors serve for the separate deter- mination of gross alpha, beta and gamma activities. In most situations, true gaseous alpha contaminants are not ofinterest. Because of these considerations, the calibration method discussed herein is limited to gaseous beta-gamma activi- ties. The monitor chambers discussed employ a chamber volume of roughly 1 ft3 and thin window