On-site calibration technology for fixed environmental gamma radiation ratemeter

The fixed environmental gamma radiation ratemeter is the main equipment to undertake environmental continuous monitoring tasks and not easy to move for metrology laboratory calibration, and the submission of a longer period affects the continuity of the continuous monitoring data. For the on time calibration of fixed environmental gamma radiation ratemeter, combined with the Monte Carlo method, the energy-compensated high-pressure ionization chamber and portable ¹³⁷Cs irradiation facility were developed. Using natural background radiation (including cosmic rays and terrestrial gamma rays) and ¹³⁷Cs gamma rays reference radiation field, the on-site calibration for fixed environmental gamma radiation ratemeter was carried out. The results show that the environment intercomparison and on-site irradiation can solve the calibration problem of fixed environmental gamma radiation ratemeters, and the relative deviation of calibration factors obtained from on-site calibration and in standard laboratory is less than 5%. (authors)