ESTRO course Dose Modelling and Verification 2017

51

Design of scattering foils

Primary foil: High Z -mtrl, e.g. Au or Ta, gives the highest linear scattering power vs. collision stopping power, i.e. the most effective scattering. Thickness (t)  0.05-0.4 mm (energy dependent).

Secondary foil: Lower Z -mtrl, e.g. Al, often used in order to reduce bremsstrahlung production. Thickness (h) < 3 mm. ~

e -

0-10 cm downstream from geom. focal point

FWHM  1-3 mm

3-10 cm further downstream

e -

Bieda et al [12]

T Knöös

Warsaw 2017