ESTRO course Dose Modelling and Verification 2017

Properties of the direct beam source

e -

Four blurring steps: 1. Electron beam distribution 2. Electron scattering in target 3. Brems X-section angular distribution 4. Coherent scatter in flattening filter (affecting the view of the source from downstream)

h n

1

Convolved with one coherent scattering event

0.8

0.6

0.4

Source distribution

0.2

11

dist [mm]

-4

-2

2

4