Optimization of PhCCD structure for star sensor

Star sensor have special performance which allows to monitor point images for low illumination levels. For the CCD sensor, this means that all of the charge generated by image photons incident on a given pixel should be collected within that pixel. Two main physical processes are determined the expected charge-collection efficiency: 3D diffusion of generated electrons and charge-transfer inefficiency. The ability of perception of low illumination stars depends on the star temperature (this temperature influences the spectral distribution of photons), quantum efficiency, and noises of the imager.