Table 8.
Calibration coefficients for the transfer chambers
| Radiation quality | 100 kV | 135 kV | 180 kV | 250 kV |
|---|---|---|---|---|
| Shonka 2022 | ||||
| NK,NIST (pre-comp)/Gy μC−1 | 8.341 | 8.415 | 8.541 | 8.661 |
| NK,NIST (post-comp)/Gy μC−1 | 8.329 | 8.394 | 8.518 | 8.636 |
| str,1 (relative) a | 0.0009 | 0.0016 | 0.0018 | 0.0019 |
| NK,BIPM/Gy μC−1 | 8.360 | 8.435 | 8.553 | 8.698 |
| Shonka 2023 | ||||
| NK,NIST (pre-comp)/Gy μC−1 | 8.420 | 8.464 | 8.581 | 8.692 |
| NK,NIST (post-comp)/Gy μC−1 | 8.415 | 8.458 | 8.569 | 8.675 |
| str,2 (relative) a | 0.0004 | 0.0005 | 0.0009 | 0.0013 |
| NK,BIPM/Gy μC−1 | 8.446 | 8.498 | 8.605 | 8.739 |
| Exradin A3 260 | ||||
| NK,NIST (pre-comp)/Gy μC−1 | 7.941 | 8.023 | 8.117 | 8.180 |
| NK,NIST (post-comp)/Gy μC−1 | 7.944 | 8.030 | 8.112 | 8.181 |
| str,3 (relative) a | 0.0002 | 0.0006 | 0.0004 | 0.0001 |
| NK,BIPM/Gy μC−1 | 7.943 | 8.042 | 8.131 | 8.223 |
a
For each pre-post pair of NK,NIST values with half-difference d, the standard uncertainty of the mean is taken to be str,i = d/√(n–1.4), where the term (n–1.4) is found empirically to be a better choice than (n–1) to estimate the standard uncertainty for low values of n. For n = 2, str,i = 1.3d.