Abstract：In order to support mammography X-ray air kerma traceability system, NIM has completed the quantitative reproduction of the mammogram X-ray air kerma rate, with an uncertainty of 0.3%. And completed the the BIPM.RI(I)-K7 key comparison work with BIPM in 2018.The calibration factor deviation of the same two transfer ionization chambers is less than 0.04%, and the comparison result uncertainty is 0.28%.The comparison result enters the key comparison database of BIPM, achieving international mutual recognition.
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2023, Vol. 44 
