Statistical analysis of the periodic intermediate checks results on the standards used for calibrations of ionizing radiation dosimeters in a ⁶⁰Co gamma ray beam

Periodic intermediate checks on the equipment used for calibration activity accredited for the conformity with the international norm ISO/IEC 17025 are an essential issue for monitoring the validity of calibration laboratory's results. These checks should be carried out according to a procedure defined by each accredited laboratory. The results of these checks should not exceed the acceptance criteria established in the laboratory and statistical techniques shall be applied to the reviewing of the results. In this work, a simple method of carrying out intermediate checks on working standards used for calibrations of ionizing radiation dosimeters in a Co-60 gamma ray beam was presented. Moreover, the statistical analysis of obtained results was presented. This analysis allowed for a reliable inference regarding the operation of the working standards used to calibrate the customer's devices. The presented methods can be used as a guidance in order to conform to the ISO/IEC 17025 requirements for carrying out and reviewing of periodic intermediate checks results in the area of calibrations of ionizing radiation dosimeters for external beam radiotherapy.