Sensor system

An infrared sensor system for use on satellites comprising dual arrays of mercury cadmium tellurice semiconductor elements is described. One array of conventional photovoltaic detectors is wired in parallel with a novel array of HdCdTe material in which the n-type region of each mesa and the resulting p-n junction is considerably smaller than that utilized in the conventional detector. As the cumulative dose of incident radiation is increased, type conversion in both arrays occurs resulting in degraded performance in the conventional array but an increase in performance caused by the now effective p-n junction area in the novel array. An electronic switching device, coupled with a dosimeter, alternately selects the conventional array or the novel array depending upon the total dose of radiation received.