Establishing IAEA TRS-457 diagnostic X-ray beam qualities at the Australian primary standard dosimetry laboratory

This paper reports the process and findings in establishing the diagnostic beam qualities for the calibration of diagnostic dose meters in the Australian primary standard dosimetry laboratory at the Australian Radiation Protection and Nuclear Safety Agency, ARPANSA. A novel iterative method to achieve the RQR beam quality requirements described by IEC 61267 is presented. The correction factors for the primary standard free-air chamber and their uncertainties are reported. The calibration procedure with detailed uncertainty budget of a typical diagnostic ionisation chamber (model PTW 34060) is reported. Beam profile measurements and details of the use of an external monitor chamber (model PTW 34014) are also reported. The uncertainty in the ARPANSA calibration coefficients is estimated to be 1.2% at k = 2 for both RQR and RQA beam qualities. The laboratory is now able to provide calibration services for radiation detectors used in general X-ray radiography.