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Gamma full energy peak

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. [Pg.22]

Carefully swirl to mix. Be certain to cover the bottom evenly, but do not swirl the solution up onto the container walls. The total initial volume is 5.0 mL. Screw the lid on the container and carefully place in position in the germanium gamma-ray detector counting chamber it should be centered and level. Count twice for a sufficient time period to accumulate 2000 counts (typically 100 s). Check to confirm that at least 2,000 counts have been accumulated at each of the peaks used for calibration. Collect the gross gamma-ray count rates for the full-energy peaks in Data Table 2B.1. [Pg.26]

Full-energy peak (or photopeak) efficiency The efficiency for producing full-energy peak pulses only, rather than a pulse of any size for the gamma ray. [Pg.139]

Figure 19.8. A composite gamma-ray spectrum of Cs, Mn, and Co. The net area of the full-energy peak (FEP), as obtained by baseline subtraction, is proportional to the activity of the radionuclide. Figure 19.8. A composite gamma-ray spectrum of Cs, Mn, and Co. The net area of the full-energy peak (FEP), as obtained by baseline subtraction, is proportional to the activity of the radionuclide.
The absolute efficiency in this calculation is the ratio of the net number of counts measured in the 1332-keV full-energy peak divided by the number of gamma rays emitted by the °Co source at this energy during the same time interval. [Pg.159]

The spectral response of a detector is more complex than described in Section 2.4.4 because of the bulk of the detector. The observed Compton continuum consists of single plus multiple successive scattering interactions. When such multiple Compton scattering interactions are terminated by a photoelectric interaction, the pulse is added to the full-energy peak. Most of the counts in a full-energy peak for gamma rays above 100 keV are due to such multiple scattering plus a final photoelectric interaction. [Pg.160]

The radionuclide is identified by the energy at the midpoint of the characteristic full-energy peak. It is quantified in terms of the count rate in the channels that define the full-energy peak. Subtracted from this count rate is the count rate in these channels due to other gamma rays discussed in Section 10.3.7 in simple cases, the background count rate per channel is the average of the count rates in one or more channels on each side of the peak. [Pg.168]

Figure 2.11 shows the gamma-ray spectra expected from the three detectors discussed. It is obvious that the bigger the detector, the more room there is for the gamma-rays to scatter around in and transfer a bigger proportion of their energy to the detector and the hence the larger the full energy peaks. These conceptual spectra may be compared to the actual gamma-ray spectra of Cs and A1 measured using an 18% Ge(Li) detector in Figure 2.12. All of the features mentioned above can be clearly seen. Figure 2.11 shows the gamma-ray spectra expected from the three detectors discussed. It is obvious that the bigger the detector, the more room there is for the gamma-rays to scatter around in and transfer a bigger proportion of their energy to the detector and the hence the larger the full energy peaks. These conceptual spectra may be compared to the actual gamma-ray spectra of Cs and A1 measured using an 18% Ge(Li) detector in Figure 2.12. All of the features mentioned above can be clearly seen.
The larger the detector, the greater the probability of complete absorption of the gamma-ray and hence a larger full energy peak and lower Compton continuum (i.e. higher peak-to-Compton ratio). [Pg.38]

Absolute total efficiency relates the number of gamma-rays emitted by the source to the number of counts detected anywhere in the spectrum. This takes into account the full energy peak and all incomplete absorptions represented by the Compton continuum. [Pg.150]

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. [Pg.150]

This is the parameter of most significance in practical gamma spectrometry. (I will denote it by the symbol alone and subscript it with the letter T (s ) to indicate the total efficiency when necessary.) The calculation of full-energy peak efficiency is straightforward it is the ratio of the number of counts detected in a peak to the number emitted by the source ... [Pg.151]


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See also in sourсe #XX -- [ Pg.387 ]




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Full-energy peak

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