PROPORTIONAL COUNTER CIRCUITRYRadiation DetectorsThe capacitor converts the charge pulse to a voltage pulse. The voltage is equal to the amountof charge divided by the capacitance of the capacitor, as given in Equation 6-8.(6-8)VQCwhereV = voltage pulse (volts)Q = charge (coulombs)C = capacitance (farads)The preamplifier amplifies the voltage pulse. Further amplification is obtained by sending thesignal through an amplifier circuit (typically about 10 volts maximum). The pulse size is thendetermined by a single channel analyzer. Figure 10 shows the operation of a single channelanalyzer.Figure 10 Single Channel Analyzer OperationThe single channel analyzer has two dial settings: a LEVEL dial and a WINDOW dial. Forexample, when the level is set at 2 volts, and the window at 0.2 volts, the analyzer will give anoutput pulse only when the input pulse is between 2 and 2.2 volts. The output pulse is usuallya standardized height and width logic pulse, as shown in Figure 11.IC-06 Page 24 Rev. 0
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