Intercomparison of γ-spectrometry analysis of radionuclides between China and Japan in 2012–2013

• An intercomparison of γ-spectrometry measurement and analysis was organized.
• Three laboratories compared the measurement of seven radionuclides.
• Results for 40K, 208Tl, 214Bi, 214Pb, 228Ac, and 137Cs were well matched between two participants.
• The results in the powder of the rice sample belonging to 134Cs were the only ones assigned “not acceptable”.

An intercomparison of γ-spectrometry measurement and analysis was organized by the Japan Chemical Analysis Center (JCAC), the National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention (NIRP, China CDC), and the Radiation Monitoring Technical Center of Ministry of Environmental Protection, Chinese (RMTC). The main objective of this study was to assess the γ-spectrometry measurement and analysis technology. The JCAC completed the collection and preparation of soil and powdered rice samples. Three laboratories compared the measurement of seven radionuclides that included two samples of 214Pb, 214Bi, 208Tl, 228Ac, 40K, 137Cs, and 134Cs with γ-spectrometry. During the studies conducted at the laboratory, the calculated value En was found to be the total uncertainty data of the reported activity. Except 134Cs in powdered rice sample, the calculated En between each of the two laboratories was <1. The measurement results are acceptable except 134Cs; therefore, measurement results in the three laboratories were consistent within a certain range except in the case of 134Cs. Although there is a need to improve the accuracy of measurements and analysis of 134Cs, an intercomparison was conducted of the tested levels on radionuclide analyzed in the three laboratories.