Table 1.
Calibration of graphite-core SSC in photon beams
| Nominal Energy (TPR20,10) | Depth cm | Field size cm×cm | SSD cm | Dose rate Gy/min | Actual dose cGy | SSC ΔT K | Calibration coefficienta | |
|---|---|---|---|---|---|---|---|---|
| Gy/K | Relative to Co-60 | |||||||
| Co-60 (0.568) | 5 | 10 × 10 | 60 | 1.4 | 141.0 | 0.0016728 | 842.6 | 1.000 |
| 6 MV (0.682) | 95 | 5.0 | 99.39 | 0.0011916 | 836.0 | 0.992 | ||
| 10 MV (0.733) | 3.9 | 99.46 | 0.0011905 | 837.1 | 0.993 | |||
| 15 MV (0.758) | 7 | 93 | 4.5 | 95.42 | 0.0011347 | 842.4 | 1.000 |
a
Corrected to 20°C, allowing for the temperature-dependency of the specific heat capacity of graphite. A correction for the beam non-uniformity over the area of the SSC core relative to the NPL2611 chamber volume was estimated from beam profile data and found to be less than 0.1% for all energies and is not included here.