Dose Course 2018_Flipping book
Detector
Appropiate for
Be careful
❑ For x-ray depth dose measurements
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
Ionization chambers
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Plane-parallel chamber for build-up region
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❑ Output factors large fields
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❑ Output factors for small fields (micro-chambers)
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Effective point of measurement
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Check stability temperature during measurements
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❑ Depth dose measurements and profiles
Energy dependence
Diodes
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Sensitivity variation with accumulated dose
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Shielded detector for x-rays
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Non-shielded for electron beams
❑ May present sensitivity variation with dose rate
Output factors
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Check stability temperature during measurements
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Shielded detector standard/large fields
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Non-shielded for small fields
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