Determination of gross α and gross β radioactivity in IAEA-2020-intercomparison samples / 中华放射医学与防护杂志

Objective:To summarize the practices in measuring the gross α and gross β radioactivity in IAEA-2020-intercomparison samples, which could be expected to be beneficial to the similar analysis and research.Methods:With 241Am, Th, 90Sr/ 90Y, 40K and 137Cs solution as standard materials, the gross α and gross β radioactivity in water and aerosol samples were determined using thin source method. With 241Am, 40K powder as standard materials, the gross α and gross β radioactivity in water and fish samples were measured using thick source method combined with evaporation. Results:The result showed that the relative deviation and Z-score by using thin source method were 4.12%-31.6% and 0.14-1.71, respectively, and those from thick source combined with evaporation were 2.63%-32.5% and 0.11-0.93, respectively, with the acceptance rate being 100%. Conclusions:Generally, standard material shall be selected in the same types of radionuclides and energies as in samples. The thin source method is appropriate for emergency monitoring in the event of an accident. The thick source combined with evaporation should be perfered to the environmental monitoring or the analysis of unknown samples in laboratory. And then an intercomparison should be done with thin source method based on the radioactivity in samples. This work can provide a technical reference for similar measurements.

Participating in the evaluation of combined value assignment of Cystatin-C as a national standard material candidate / 国际检验医学杂志

Objective As a collaborator of Beijing Institute of Medical Device Testing for value assignment of state standard ma-terial candidate Cystatin-C ,we have used the internationally accepted reference material to assign value for state standard material candidate Cystatin-C ,and help Beijing Institute of Medical Device Testing get Cystatin-C national standard material certificate . Methods According to the target value and operational procedure of international reference material ERM-DA471 ,We have tested 6 dilutions of standard material candidate Cystatin-C on calibrated Hitachi 7180 immunoassay system .Results The results demon-strate good repeatability and commutability ,and have been accepted in calculating the final value for the candidate standard materi-al ,our data has assisted Beijing Institute of Medical Device Testing in passing the criteria and obtaining Cystatin-C national standard material certificate .Conclusion Compared to the data from all participating collaborators ,our results hit right on the target value , and no significant matrix effects have been observed .