Radiation DetectorsSOURCE RANGE NUCLEAR INSTRUMENTATIONThe logarithmic count rate signal is differentiated to measure the rate of change in neutron flux.The differentiator output is proportional to reactor period. The value of reactor period isinversely proportional to the actual rate of change of reactor power and relates to power changesby factors of e (2.718). The power rate change based on factors of 10, in decades per minute,is more meaningful to the reactor operator. Therefore, the output of the differentiator isconverted from reactor period to decades per minute through the meter scale used.SummaryThe purposes of source range components are summarized below.Source Range Instrumentation SummaryThe linear amplifieramplifies the input signal by a factor of several thousandto raise the pulse height to several volts.The discriminator excludes passage of pulses that are less than a predeterminedlevel.The pulse integratorprovides an output signal proportional to the logarithm ofthe count rate.The log count rate amplifieramplifies the signal for display on a meter.The differentiatorprovides an output signal proportional to the rate of powerchange.Rev. 0 Page 65 IC-06