Key comparison BIPM.RI(I)-K1 of the air-kerma standards of the LNE–LNHB, France and the BIPM in⁶⁰Co gamma radiation

Abstract

An indirect comparison of the standards for air kerma of the Laboratoire National de Métrologie et d'Essais -Laboratoire National Henri Becquerel (LNE-LNHB), France and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 60 Co radiation beam of the BIPM in April 2013. The comparison result, evaluated as a ratio of the LNE-LNHB and the BIPM standards for air kerma, is 0.9994 with a combined standard uncertainty of 1.8  10 -3 . The results are analysed and presented in terms of degrees of equivalence for entry in the BIPM key comparison database.

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).…”

“…Further, following the BIPM.RI(I) comparison publications [9][10][11][12][13][14][15] a degree of equivalence linked to BIPM.RI(I)-K1 and BIPM.RI(I)-K4 among the actual calibration coefficient data N(X)Lab i may be calculated as "(N(X)Lab i / N(X)BIPM) -1" expressed in "mGyGy-1" (Table 7). Ideally, for the linking laboratories, the values of N(DW)Lab i / N(DW)BIPM should give the same results than those obtained during their comparison with the BIPM (R(X)Lab i, BIPM in Table 6).…”

“…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].…”

“…This goes beyond the protocol of this comparison.Further, the results are linked to the CCRI(I) key comparisons BIPM.RI(I)-K1 and BIPM.RI(I)-K4 through the linking laboratories BEV, LNE-LNHB and VSL for the air kerma and through BEV, LNE-LNHB and METAS for the absorbed dose to water standards. A degree of equivalence calculation for the actual comparison results is proposed according to the BIPM.RI(I) comparison publications[9][10][11][12][13][14][15]…”