Quality Assurance of Radiation Protection Monitoring Instruments in India

Bhabha Atomic Research Centre (BARC) is the National Metrology Institute (NMI) for developing, maintaining and disseminating standards for ionizing radiation in India. Radiation Safety Systems Division (RSSD) of BARC has the requisite infrastructure in the form of experts, trained manpower, laboratories, equipments and facilities for providing calibration services to users and ascertaining traceability to international standards. It periodically participates in various international inter-comparisons. RSSD maintains reference radiation fields that are required for calibrating Radiation Protection Monitoring Instruments that form the backbone of the radiation monitoring programme for harnessing the benefits of nuclear energy and ionizing radiations. These instruments are type-tested and periodically calibrated at standard reference radiation fields to ensure their healthy working condition and fitness for their intended use. This paper describes the details of the standardization procedures adopted for reference radiation fields and infrastructure established and maintained at RSSD, BARC in accordance with the recommendations of ISO-4037. The paper describes the various tests that are carried out for radiation protection monitoring instrument to study the variation of the calibration factor with influencing quantities like linearity of response, energy response, angular dependence and overload characteristics. The results of these tests for typical instruments are also discussed. The present work also describes various types of indigenously developed radiation protection monitoring instruments and their performance characteristics. Adaptability of these instruments for the implementation of operational quantities are discussed briefly. It also dwells on the IAEA Quality Audit for radiation protection level calibrations, which RSSD has been participating since 2001. Our results of the quality audit are well within the acceptance limit (±7%) set by IAEA for the participating laboratories.