Detector preamplifier amplifier combination

In general, the detectors are combined with a preamplifier, an amplifier and a multichannel analyser, in which the pulses are sorted according to their pulse heights. Frequently, the multichannel analyser is operated by a computer and a program for peak search, peak net area calculation, energy calibration and radionuclide identification. 

X-ray spectrometry is generally carried out with Si(Li) detectors. The set-up is similar to that applied to y-ray spectrometry with i-Ge or Ge(Li) detectors cooling of the detector in a cryostat, operation in combination with a preamplifier, an amplifier and a multichannel analyser. The energy resolution is very good, as already mentioned in section 7.6, and makes it possible to distinguish the characteristic X rays of neighbouring elements. Some X-ray emitters that may be used for calibration purposes are listed in Table 7.6. 

An interferogram converted into electric signals by the detector is received by the computer via a combination of preamplifier, main amplifier, electric filter, sample-and-hold circuit,... 

Signals from each He tube are processed individually by an amplifier and discriminator (Precision Data Technology, Inc., Model 1 lOA), and the combined neutron cormts from all tubes are stored in a computer. The power used by the detector is about 6 watts, not including the laptop computer. During some of the tests to characterize the detector s response, we used alternative electronics (Ortec 142PC preamplifiers and Ortec 572 amplifiers) to monitor spectrum shapes and possible temperature-related gain shifts with a multichannel analyzer. 

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