Restricted Energy Absorption Coefficients for Use in Dosimetry

locally in some region RA. For computational reasons the size of region RA is chosen to correspond to the range of secondary electrons of some restriction energy A. The energy restriction, A, of the mass energy absorption coefficient is related to the energy restriction of the mass stopping power to be used with the same region. The restricted mass energy absorption coefficient can be used in situations where there is a lack of charged particle equilibrium and the usual mass energy transfer coefficient cannot be used to calculate the locally absorbed energy from a photon fluence. Thus it may be used in cavity chamber theory to calculate that fraction of the absorbed dose to a detector which is due to photon interactions inside the detector itself.