Detectors scaling pulse-count

The scaling pulse-counting detector comprises three functionally distinct sections, as shown in Figure 3.19. 

Figure 3.20 Attenuation of the measured output pulse rate of a scaling pulse-counting detector with changes in the control voltage. Measurements were taken with a Varian UltramassZOO ICP-MS and using an ETP model DM1 69B detector. Data courtesy of Varian Australia (2003).

The log count rate amplifier then amplifies the signal, which varies directly as the logarithm of the pulse rate, in the detector. The logarithmic count rate is then displayed on a meter with a logarithmic scale in counts per second. 

The Mossbauer spectrometer will typically divide the velocity scale into 256 channels. For a 0.93 GBq source (25 mCi), the total count rate of photons arriving at the detector and having the proper pulse-height is usually about C = 20,000 counts s Only about 85% of these will be 14.4 keV radiation the others are... 

Time-resolved fluorimetry is also useful for the elimination of interferences from stray light due to Rayleigh and Raman scatter. The latter phenomena occur on a time scale of l(r14-l(T13 s and, as they have a much shorter duration than lamp or laser pulses, the light associated with them can be eliminated from the signal that ultimately reaches the detector. Time-correlated single-photon counting is superior in its ability to resolve multiple fluorescence from the same solution. 

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