Key comparison BIPM.RI(I)-K9 of the absorbed dose to water standards of the LNE-LNHB, France, and the BIPM in medium-energy x-rays
A key comparison has been made between the absorbed dose to water standards of the LNE-LNHB, France, and the BIPM in the medium-energy x-ray range. The results show the standards to be in general agreement at the level of the expanded (k = 2) uncertainty of the comparison of 2 parts in 102. The results are presented in terms of degrees of equivalence for entry in the BIPM key comparison database. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Degrees of equivalence for the key comparison BIPM.RI(I)-K3 between national primary standards for medium-energy x-rays
Results are presented of comparisons of eleven national primary standards for air kerma with the BIPM primary standard over the range of x-radiation qualities from 10 kV to 50 kV. For each radiation quality, the results are analysed in terms of the degree of equivalence, Di, of each national standard i with respect to the key comparison reference value. The degrees of equivalence, Dij, between each pairing of national standards i and j are also evaluated. These data form the basis of the matrices and graphs of results entered in the BIPM key comparison database for comparison BIPM.RI(I)-K2. Main text. To reach the main text of this paper, click on Summary Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The summary report has been peer-reviewed and approved for publication by the Consultative Committee for Ionizing Radiation (CCRI), according to the provisions of the Mutual Recognition Arrangement (MRA).
Commissioning of an NRC-type sealed water calorimeter at METAS using 60Co gamma-rays.
As part of a collaborative project between the National Research Council of Canada (NRC) and the Swiss Federal Office of Metrology and Accreditation (METAS), a sealed water calorimeter was built at NRC and transferred to METAS. The calorimeter is operated at 4 degrees C and uses two thermistor probes in a sealed glass vessel containing high-purity water to measure the radiation-induced temperature rise. The various correction factors have been evaluated and the estimated standard uncertainty on the absorbed dose to water is 0.41%. An extensive set of measurements using 60Co gamma-rays was carried out at NRC and two ionization chambers were calibrated against the absorbed dose determined calorimetrically. The chambers were also calibrated against the NRC standard for absorbed dose. After transferring the calorimeter to METAS, a similar set of measurements was carried out using their 60Co beam and the same two ionization chambers were calibrated against the absorbed dose to water established at METAS. The discrepancy between the three sets of calibration coefficients was smaller than the estimated standard uncertainty of 0.47% on the ratio of any pair of calibration coefficients.