Precision ionization chamber measurements of natural background radiation (near nuclear reactors)

Abstract

An ionization chamber system has been developed to make precise measurements of natural background radiation. The system consists of a 16 litre, muscle equivalent ionization chamber, a vibrating reed electrometer, a printing digital voltmeter and a strip chart recorder. The system is battery powered for field operation. It has been used to measure the background radiation around several nuclear reactor sites. The electrometer is used in the current-integrate mode. Six to ten measurements are made at each station. The background radiation so measured has varied from 4 to 10 mu rad h-1 with 95% confidence limits of about 2 to 3%.