Advanced Physics for Brachytherapy 2018
Sensitivity, calibration & energy response:
Our calibration coeff. (inverse of dosimeter A.D. sensitivity) actually comprises 2 parts:
) ( QwD
) ( det D Q D Q ) (
) ( QM Q
) ( det
wD
) ( , QwADN =
f
) ( QbqkQ
=
=
) (
M
Q
) (
• we define the absorbed dose energy dependence of the detector as the ratio of dose to water per unit dose to the detector at a given beam quality,
) ( det Q D QD w ) (
f
Q
) ( =
This depends on physical properties and radiation quality (cross sections) and detector geometry. It can be calculated via MC!
• We define the intrinsic energy dependence of the detector as the ratio of dose required to be absorbed to produce a unit signal
) ( Q D
det
) Q k bq = (
) ( QM
This depends mainly on the physical process underlying the conversion of dose to the measured signal (and hence LET). It can only be measured!
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