Nuclear Radiation Induced Noise in Infrared Detectors

A model for calculating the rate and amplitude of gamma ionization events in infrared detectors is presented. Several simplifying approximations to the actual, complex physical situation are applied in the model, thereby allowing an exact analytical formulation of the problem. Experimental measurements of nuclear-radiation induced noise pulse-height distributions and event rates are compared to predictions made using the model. Comparisons of experiment and theory were made at several different gamma energies to provide confirmation of the model over the gamma energy range of interest of most application. The experimentally-confirmed model allows prediction of the noise response of photoconduction detectors for any specified detector material, geometry, surrounding material and incident gamma spectrum.