Comparison of the standards for absorbed dose to water of the PTB, Germany and the BIPM for ⁶⁰Co γ rays

Abstract

A comparison of the standards for absorbed dose to water of the Physikalisch-Technische Bundesanstalt (PTB), Germany and of the Bureau International des Poids et Mesures (BIPM) has been made in 60Co gamma radiation under the auspices of the key comparison BIPM.RI(I)-K4. The comparison result, based on the calibration coefficients for three transfer standards and expressed as a ratio of the PTB and the BIPM standards for absorbed dose to water, is 0.9961 (0.0037). This result replaces the earlier PTB value in this key comparison. The degrees of equivalence between the PTB and the other participants in this comparison have been calculated and the results are given in the form of a matrix for the twelve national metrology institutes (NMIs) that have taken part in the ongoing comparison for absorbed dose to water. A graphical presentation is also given.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 Section I of the Consultative Committee for Ionizing Radiation (CCRI(I)), according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Reference dosimetry for helical tomotherapy: Practical implementation and a multicenter validation

“…However, both calorimetry systems have been compared to the primary standard operated at the BIPM and are in mutual agreement within 0.1%. 32 Comparing the beam output of the open=rotational mode (test B) to the static output (test A) differences are found within 0.2%, except for the UCL site where a difference of 1.3% is observed. The reason for this deviation remains unclear and could be attributed to either a limited statistics or to some yet unknown operational situation; the tomotherapy HiArt machine at this site belongs to a first generation system.…”

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]).…”

A blind test of the alanine dosimetry secondary standard of the PTB conducted by the BIPM

“…The continuous line indicates the average value of the ratio. The ratio of the D W primary standards of the PTB and the BIPM of 0.9961 [19] is indicated by the thick, dashed line; the standard uncertainty of this ratio of 0.0037 is represented by the thin dashed lines.…”

“…Nine detectors consisting of four alanine pellets each were irradiated in the 60 Co reference beam at the BIPM. The doses Dashed, thick line: ratio of the primary standards for absorbed dose to water of the PTB and BIPM [19]. The thin dashed lines indicate the standard uncertainty of the primary standard ratio.…”