Table 3 The uncertainty components for measurement of the absorbed dose rate to water
Uncertainty component | Type A (%) | Type B (%) |
|---|---|---|
Calibration factor of the ionization chamber, \( {N}_{D_w,{Q}_0}^c \) | 0.50 | |
Ionization current measurement | 0.01 | 0.02 |
Temperature and pressure measurement | 0.056 | |
Scattered photon contribution | 0.01 | 1.28 |
Displacement of the ionization chamber | 0.01 | 0.15 |
Alignment of the PMMA phantom with the PPS calibration center | 0.20 | |
Long-term stability of the ionization chamber | 0.12 | |
Standard relative combined uncertainty | 1.40 | |