Methods and apparatus for stabilizing the gain of a radiation detector

In accordance with an illustrative embodiment of the present invention, a technique for stabilizing the gain of a radiation detector is described. In this technique, a reference radiation source having a predetermined energy spectrum is located adjacent or enclosed within a scintillator of a radiation detector. Those signals produced by the radiation detector which represent energies within an energy range defined by the reference source energy spectrum are selected and used to determine the relationship between the energy spectrum of the reference source and the energy spectrum of the selected detector signals. From this relationship a reference signal is generated which is used to adjust the radiation detector gain in a non-linear manner to cause the energy spectrum of the selected radiation detector signals to correspond to that of the reference radiation source. The system was designed especially for stabilizing the gain of gamma spectrometers for gamma-gamma well logging systems