Measurement of the output of ISO recommended beta sources with an extrapolation chamber

Output measurements in terms of absorbed dose rate to tissue were carried out for the ISO (International Organization for Standardization) recommended beta sources ⁹⁰Sr/⁹⁰Y, ⁸⁵Kr and ¹⁴⁷Pm using an extrapolation chamber. A holder made of anodized aluminium for the extrapolation chamber for the output measurements was designed indigenously. The measured dose rates for three beta sources were compared with the corresponding values provided in the certificate by the Physikalisch-Technische Bundesanstalt (PTB), the National Standard Laboratory of Germany. Depending upon the source and source-to-chamber distance, the PTB certificate values have uncertainties in the range ±1.2–±1.5%. The measured dose rates have uncertainties of about ±0.3%. The deviations between the measured dose rates and the PTB certificate values compare well (maximum deviation is about 2%) considering the combined uncertainties associated with the measurements and the certificate values. The study suggests that the beta irradiation system comprising the above beta sources can be utilized for quality assurance programme related to personnel monitoring services in India. - Highlights: • Absorbed dose rates to tissue were measured for ⁹⁰Sr/⁹⁰Y, ⁸⁵Kr and ¹⁴⁷Pm ISO recommended beta sources with extrapolation chamber. • A holder made of aluminium was designed indigenously for the extrapolation chamber. • The measured dose rates agree well with the values provided in the PTB certificate. • The study suggests beta sources can be utilized for QA programme in personnel monitoring services