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OF measurements in a 6 MV beam
using Pinpoint ion chamber (15 mm
3
).
Martens
et al
[12]
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.
Measured OF rel. 125 mm
3
ion chamber
Energy dependence (non water equivalence central electrode)
10%