Comparison of the standards for absorbed dose to water of the VSL and the BIPM for⁶⁰Co γ-rays

Abstract

An indirect comparison of the standards for the quantity absorbed dose to water was carried out between the Van Swinden Laboratorium (VSL) and the Bureau International des Poids et Mesures (BIPM) in September 2005. The comparison was based on the calibration coefficients determined for three NE2611A type ionization chambers under reference conditions in the 60Co beams of both institutes. The comparison result, reported as a ratio of the VSL and the BIPM evaluations, is 0.9926 with a relative standard uncertainty of 4.9 × 10−3. This result replaces the previous indirect comparison result obtained in 2000 for the ongoing BIPM.RI(I)-K4 comparison. The degrees of equivalence for the VSL standard and the nine other national metrology institutes in this comparison are presented in the form of a matrix, together with those of a linked regional comparison. The opportunity was also taken to undertake a pilot study using the VSL water calorimeter at the BIPM.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 Section I, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

A water calorimeter for on-site absorbed dose to water calibrations in60Co and MV-photon beams including MRI incorporated treatment equipment

“…Table 6 gives the ratio between D w,ref obtained with the new calorimeter WCM-02 and WCM-01. The presented relative standard uncertainties of D w,ref , u, for WCM-02 are given in table 3 and for WCM-01 is reported by Kessler et al (2009). Additionally, the type A relative standard uncertainties, u A , of measurements WCM-01 (0.05% for n = 17) and WCM-02 (0.05% for n = 5) are given in table 6.…”

New standards of absorbed dose to water under reference conditions by graphite calorimetry for60Co and high-energy x-rays at LNE-LNHB

“…A recent review of the different methods to measure photon absorbed dose can be found in the literature [1]. Some of the NMIs use water calorimetry (METAS-Switzerland, NIST-USA, NRCC-Canada, PTB-Germany, VSL-Netherlands [2][3][4][5][6][7][8][9][10]) and others use graphite calorimetry (BIPM, ARPANSA-Australia, BEV-Austria, ENEA-INMRI-Italy, NMIJ-Japan, NPL-United Kingdom, VNIIFTRI-Russia [11][12][13][14][15][16][17][18][19][20][21][22][23][24]).…”

Comparisons of air kerma and absorbed dose to water standards in Co-60 radiation beams for radiotherapy

“…The degree of equivalence for entries in the BIPM key comparison data base in terms of air kerma and in terms of absorbed dose to water was established by linking the ratios as defined above to the BIPM.RI(I)-K1 and BIPM.RI(I)-K4 key comparisons respectively through laboratories having participated in one or both comparison exercises [9][10][11][12][13][14][15]. Thus, the linking factor Q(X)Lab i = R(X)Lab i, mean / R(X)Lab i, BIPM can be defined with R(X)Lab i, BIPM being the result from the corresponding CCRI(I) key comparison and (X) standing for either (KAir) or (DW).…”

“…The linking laboratories BEV, LNE-LNHB and VSL for the air kerma and BEV, LNE-LNHB, and METAS for the absorbed dose to water standards allow discussing the results in terms of degree of equivalence with respect to the BIPM.RI(I)-K1 and BIPM.RI(I)-K4 key comparisons [9][10][11][12][13][14][15].…”