APMP/TCRI key comparison report of measurement of air kerma for medium-energy x-rays (APMP.RI(I)-K3)

Abstract

The APMP/TCRI Dosimetry Working Group performed the APMP.RI(I)-K3 key comparison of measurement of air kerma for medium-energy x-rays (100 kV to 250 kV) between 2000 and 2003. In total, 11 institutes took part in the comparison, among which 8 were APMP member laboratories. Two commercial cavity ionization chambers were used as transfer instruments and circulated among the participants. All the participants established the 100 kV, 135 kV, 180 kV and 250 kV x-ray beam qualities equivalent to those of the BIPM. T he results showed that the maximum difference between the participants and the BIPM in the medium-energy x-ray range, evaluated using the comparison data of the linking laboratories ARPANSA and PTB, is less than 1.4 %. The degrees of equivalence between the participants are presented and this comparison confirms the calibration capabilities of the participating laboratories.

Key comparison BIPM.RI(I)-K3 of the air-kerma standards of the ENEA, Italy and the BIPM in medium-energy x-rays

“…It follows that for each laboratory i having a BIPM comparison result x i with combined standard uncertainty u i , the degree of equivalence with respect to the reference value is the relative difference D i = (K i -K BIPM,i ) / K BIPM,i = x i -1 and its expanded uncertainty U i = 2 u i . The results for D i and U i , expressed in mGy/Gy and including those of the present comparison, are shown in Table 13 and in Figure 1, which include the linked results of the corresponding regional key comparison APMP.RI(I)-K3 (Lee et al 2008). Note that these data, while correct at the time of publication of the present report, become out of date as laboratories make new comparisons with the BIPM.…”

Key comparison BIPM.RI(I)-K3 of the air-kerma standards of the ARPANSA, Australia and the BIPM in medium-energy x-rays

“…It follows that for each laboratory i having a BIPM comparison result x i with combined standard uncertainty u i , the degree of equivalence with respect to the reference value is the relative difference D i = (K i -K BIPM,i ) / K BIPM,i = x i -1 and its expanded uncertainty U i = 2 u i . The results for D i and U i , expressed in mGy/Gy and including those of the present comparison and those of the linked APMP.RI(I)-K3 comparison [9], are shown in Table 13 and in Figure 1.…”

Key comparison BIPM.RI(I)-K3 of the air-kerma standards of the MKEH, Hungary and the BIPM in medium-energy x-rays

“…It follows that for each laboratory i having a BIPM comparison result x i with combined standard uncertainty u i , the degree of equivalence with respect to the reference value is the relative difference D i = (K i -K BIPM,i ) / K BIPM,i = x i -1 and its expanded uncertainty U i = 2 u i . The results for D i and U i , expressed in mGy/Gy and including those of the present comparison and those of the linked APMP.RI(I)-K3 comparison [10], are shown in Table 13 and in Figure 1. Note that these data, while correct at the time of publication of the present report, become out of date as laboratories make new comparisons with the BIPM.…”