Design and optimization of a space camera with application to the PHI solar magnetograph

A camera based on a customized Active Pixel Sensor has been designed, characterized, and qualified for application in space. The camera was optimized for its implementation in solar magnetographs. The control electronics of the camera aims at minimizing the noise at high readout speeds and under variable operating conditions. In addition, the control module protects the sensor against single event effects caused by space radiation. Characterization results of both image sensor and camera reveal their electrical and electro-optical performances. Moreover, three radiation campaigns have allowed studying the tolerance of the customized detector against ionizing doses, non-ionizing doses, and single event effects. Radiation significantly increases the dark current of the sensor and provokes smaller effects in other parameters. Post-irradiation tests demonstrate that those effects can be partly overcome if proper in-flight annealing and operating temperatures are guaranteed. The implemented protection of the detector against transient effects successfully avoids permanent functional failures of the camera. An application analysis shows how the camera characteristics as well as its combined operation with the rest of the instrument units influence the polarimetric and timing performance of the PHI magnetograph. This analysis results in both, a definition of the minimum camera requirements and an optimum strategy to jointly operate polarization, spectral, and imaging modules. The camera electronics and APS sensor have surpassed these derived minimum performances and operating conditions. results.