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Detector
Appropiate for
Be careful
Ionization
chambers
For x-ray depth dose
measurements
Plane-parallel chamber for build-
up region
Output factors large fields
Output factors for small fields
(micro-chambers)
Check polarity effect for both photon
and electron beams
Always measure with the same
nominal V
For micro-chambers the stem signal
can be an issue
Correct by Sw,air for electron depth
dose measurements.
Use small volume detectors for
scanning
Effective point of measurement
Check stability temperature during
measurements
Diodes
Depth dose measurements and
profiles
Shielded detector for x-rays
Non-shielded for electron beams
Output factors
Shielded detector standard/large
fields
Non-shielded for small fields
Energy dependence
Sensitivity variation with accumulated
dose
May present sensitivity variation with
dose rate
Check stability temperature during
measurements