Dose Course Book

640-641 / 2239

OF measurements in a 6 MV beam
using Pinpoint ion chamber (15 mm3).
Measured OF rel. 125 mm3 ion chamber
Energy dependence (non water equivalence central electrode)
Old PTW chamber 31006
with a central electrode of
steel causing similar
behaviour as an Si diode.
New PTW pinpoint
chambers 31014-6 have
aluminium central
electrodes.
10%
Martens et al [12]