DETERMINATION OF DOSE-RATES IN BETA-RADIATION FIELDS USING EXTRAPOLATION CHAMBER AND GM COUNTER

The extrapolation chamber measurement method is the basic method for t he determination of dose rates in beta radiation fields and the method has been used for the establishment of beta calibration fields. The p aper describes important details of the method and presents results fr om the measurement of depth-dose profiles from different beta radiatio n fields with E(max) values down to 156 keV. Results are also presente d from studies of GM counters for use as survey instruments for monito ring beta dose rates at the workplace. Advantages of GM counters are a simple measurement technique and high sensitivity. GM responses were measured from exposures in different beta radiation fields using diffe rent filters in front of the GM detector and the paper discusses the p ossibility of using the results from GM measurements with two differen t filters in an unknown beta radiation field to obtain a value of the dose rate.