Detector efficiency intrinsic total

Intrinsic total detector efficiency is the probability that a gamma of a given energy which strikes the detector will be recorded. The geometry assumed for the calculation or measurement of this efficiency is shown in Fig. 12.11. 

Absolute total detector efficiency is the probability that a gamma emitted from a specific source will be recorded in the detector. The geometry assumed for the absolute efficiency is shown in Fig. 12.12. The intrinsic efficiency (Fig. 12.11) depends on the energy of the gamma E and the size of the detector L. The absolute total efficiency (Fig. 12.12) depends on, in addition to E and L, the radius of the detector R and the source-detector distance d. Therefore the absolute total efficiency, as defined here, is the product of intrinsic efficiency times the solid angle fraction (see also Chap. 8). 

The double- and single-escape peak efficiencies are used with semiconductor detectors only. In the above definitions, if the total detector efficiency is replaced by intrinsic, the corresponding full-energy, single-, and double-escape peak efficiencies are also considered intrinsic. 

Intrinsic efficiency (full energy peak or total) relates the counts in the spectrum to the number of gamma-rays incident on the detector. This efficiency is a basic parameter of the detector and is independent of the source/detector geometry. 

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