Figure 4

Simulated BB dose as a function of depth in a Gammex RMI457 Solid Water^® phantom using Geant4 for a 3 T wiggler field and a BDA of (a) 2.014 mm (b) 1.053 mm and (c) 0.532 mm height. Measured data using a PTW PinPoint® ionisation chamber and EBT3 film are overlayed.