Results of radiation tests performed on the ISOCAM infrared detector array

Extensive radiation tests have been performed on the long-wavelength infrared detector array for the ISOCAM camera, to be launched on the ISO European satellite. Transient and memory effects, induced by gamma -rays, protons, and heavy ions have been investigated. Each time a pixel is traversed by a particle, an ionization pulse is generated. The results of different deglitching techniques have been compared. Among them, the half Gauss method seems to be the best. In addition to the transient effect, a memory effect is induced by the radiation: an increase of the photoconductive gain is observed. For 2 rad, the raise in responsivity is about 60%. The relaxation time is the order to 1 h. The relativistic Fe ions present in cosmic rays have been simulated by Ar ions of 70 MeV/nucleon energy. These very heavily ionizing particles induce a large responsivity change, not only in the pixels directly hit by the particles, but also in their neighbors. No permanent damage was observed after irradiation: the initial characteristics were recovered after a few hours and the noise remained unaffected.<
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