Abstract: In order to check and promote the improvement of calibration ability and the technical ability of operators,and ensure the reliability of monitoring data,the measurement and comparison work of environmental nuclear radiation monitoring instrument was carried out.The intercomparison includes environmental level dosemeters, protection level dosemeters which coverage for environmental level,and γ-ray air kerma secondary standard ionization chamber.The intercomparison parameters involve air kerma and ambient dose equivalent.The intercomparison covers a wide range of environmental nuclear radiation monitoring instruments.X-ray response,γ-rays and cosmic rays response properties of the environmental nuclear radiation monitoring instruments were studied.The E_n value and relative error were compared to analyze and evaluate the results.As the intercomparison results,the E_n values of standard ionization chambers in calibration laboratory are less than 1,and all meet requirements.Most of the environmental radiation monitoring instruments meet the requirements of S-Cs measurement.However,the X-ray response of most monitoring instruments are poor.Some monitoring instrument cannot meet the requirements that the energy response variation limit dose not exceed ±30%,so it is recommended that the instrument user should verify its energy response during the first inspection.

Key words: Environmental nuclear radiation, γ-rays, Air kerma, Intercomparison