Supplementary comparisons of the calibration of low energy x-ray air kerma standards

Project Description

The objective of this comparison is to support the three SSDLs' CMCs for low energy x-ray calibration of ionization chambers in terms of air kerma. For this purpose a comparison is proposed between the air kerma standards of the NRPA, SSM, STUK and the LNE-LNHB in the x-ray range from 10 kV to 50 kV. The comparison radiation qualities are the CCRI low energy x-ray beams and two mammography bemas W/Mo28 and W/Mo35. The transfer ionization chambers of type Radcal RC6M were selected.

Final Report 2018-06-01

The comparison has been completed and results are published in Metrologia's Technical Supplement and in the KCBD

Abstract
A supplementary comparison has been made between the air-kerma standards of the NRPA, Norway, the STUK, Finland, the SSM, Sweden and the LNE-LNHB, France in the low-energy x-ray range, and between the NRPA and the LNE-LNHB in the mammography x-ray range. The technical protocol was approved by the CCRI(I) in April 2016. The results show the standards to be in agreement at the level of the standard uncertainty of the comparison of 6.8, 10.0 and 7.4 parts in 10^3 for the NRPA, the STUK and the SSM respectively. For mammography, the standard uncertainty was 5.3 parts in 10^3 for the NRPA. The results are analysed and presented in terms of degrees of equivalence.

Reference.
Metrologia, 2018, 55, Tech. Suppl., 06008