Table 2.
Monte Carlo simulated beam characteristics of GSF spectra incident upon air at 20 °C under free-in-air conditions and under PMMA phantom backscatter conditions.
| GSF spectrum codes | Average energy (keV) | Primary+backscatter versus primary | |||
|---|---|---|---|---|---|
| Primary (free-in-air) | Primary+backscatter (on-phantom) | Photon-fluence ratio | Energy-fluence ratio | Air kerma ratio | |
| 49 (UW-60M) | 34.4 | 33.9 | 1.308 | 1.288 | 1.307 |
| 60 (UW-80M) | 43.9 | 42.6 | 1.365 | 1.323 | 1.392 |
| 71 (UW-100M) | 54.0 | 51.4 | 1.407 | 1.339 | 1.463 |
| 80 (UW-120M) | 60.4 | 57.0 | 1.418 | 1.338 | 1.466 |