Abstract:To improve the capacity of radon metrology in China, the standard radon monitors from 11 standard laboratories were calibrated uniformly. The low-level concentration comparison was conducted base on the unified calibration. The unified calibration was carried out at 700~3000Bq/m3 radon concentration, and the reference value of radon concentration can be traced to the primary standard of radon activity, Urel=1.6% (k=2). The range of response to reference radon atmosphere for standard radon monitors are 0.93~1.02, and the uncertainties range are 2.2%~3.6% (k=2). The low-level concentration comparison was carried out at 100~400Bq/m3, the most standard radon monitors En<1. By optimizing the strategy, it is feasible for standard radon moniters to transfer above 100Bq/m3. However, it is necessary to improve the ability of measurement and concentration control for each laboratory to carry out transfer at concentration of 100Bq/m3 or below.
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