IR-Detector-Types For Short Distance Seeker Ammunition Application

A significant improvement in performance of classical ammunition has become possible by using intelligent fuzes. For short target distance applications the use of Single or Dual Mode IR-Sensors has become state of the art. Excessive requirements to both axial and radial g-load arise from the fact that the sensor, normally positioned excentrically relative to shells rotating axis, has to withstand the cannon launch. High requirements on temperature stability, microphonic noise insensitivity and cross talk are essential for high sensor performance. The response has to be stable over an extended temperature range from -46 degrees C to +63 degrees C. Insensitivity against microphony prevents mechanical vibration induced reduction of sensor signal noise ratio, and low detector element cross talk guarantees high spatial resolution and therefore target classification. In addition, by means of a 20-year wooden round concept, there is a strong requirement for long-term stability. The choice of detector material and operation temperature is essentially determined by cost effectivness. All the requirements mentioned above can be met with different results depending on different detector materials. The usability of some detector materials for intelligent ammunition application has been investigated comparatively by theory and experiments. In a feasibility study different pyroelectrics, thermic detectors, as well as the photonic detectors (thermoelectrically cooled photo conductors), lead sulfide (PbSe) and mercury cadmium telluride (MCT), have been compared.