Gegen elektromagnetische Impulse geschütztes optisches Detektionssystem

This optical detection system includes a photodetector (1) placed in an enclosure (4) electrically continuous except for an input window (10) through which the optical radiation to be detected is transmitted to the photodetector (1). The protection of the optical detection system against electromagnetic pulses is achieved by the input window (10) including two parallel plates (5 and 6), spaced apart and transparent to the radiation to be detected, the space (7) delimited by the parallel sides of the transparent plates (5 and 6) and the edge of the conductive enclosure (4) on which the plates (5 and 6) are mounted being occupied by a rarefied gas transparent to the radiation to be detected in normal operation, and ionizable in case of an electromagnetic pulse to form then a continuous enclosure around the photodetector (1). Rapid ionization of the gas may be speeded up by providing a trace of radioactive material in the space 7 or by providing conductive strips on the inner faces of plates 5 and 8.