Detector efficiency full-energy peak

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. 

In this experiment, the Ge detector with spectrometer is calibrated for its efficiency, s, with a standard that emits a set of gamma rays at energies that span the range of interest, usually from a few keV to 1.5 MeV. The counting efficiency is calculated from the ratio of the net count rate to the reported disintegration rate at each full-energy peak in the spectrum. A correction for radioactive decay is needed. 

An example of a full-energy peak efficiency curve for a germanium detector is shown in Fig. 5.19. 

The efficiency of Ge detectors quoted in the list of specifications by the manufacturer may be a relative full-energy peak efficiency or an absolute... 

Figure 2 the estimated sensitivity of the presented instrument is shown together with the sensitivities of past, present and futur telescopes. For a crystal lens telescope, the point source sensitivity depends on the diffraction efficiency of the lens, the full energy peak efficiency and the background of the detector. 

McFarland, R.C. (1991). Behavior of several germanium detector full-energy-peak efficiency curve-fitting functions, Radioact. Radiochem., 2, 4-10. 

Compton level) increases at a lower rate than the full-energy peak efficiency (which is proportional to the size). The logical conclusion is that the MDA will decrease rather more than would be expected from the increase in detector size. To quantify that, we can resort to Equation (13.6) again. In this case, FWHM and t are constant and we can take B as equivalent to 5r and relative efficiency as a measure of e. Then, taking the data from Figure 13.2, comparing a 30% detector and a 90% detector at 325 keV we get ... 

ABSOLUTE EFFICIENCY The efficiency of a detector expressed as number of entities detected compared to number emitted by the source. Can bt full-energy peak efficiency or total efficiency. 

Orphan et al. ° have reported the use of a Ge(Li) detector with split NaI(Tl) annular shield to provide y-spectrometry with Compton suppression and pair spectrometry facilities. The pair spectrometer mode of operation is of most value in the energy range 3—7 MeV where the double escape detection efficiency is comparable to the full energy peak efficiency. 

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. 

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