ESA's CCD test bench for the Euclid visible channel

The visual imaging instrument VIS on board Euclid baselines 36 newly designed CCD273-84 devices from e2v. While these new devices have a 4kx4k format with four readout nodes, the Euclid Imaging Consortium (EIC) has performed extensive test campaigns on both irradiated and un-irradiated devices of the 4kx1k Euclid precursor variant CCD204-22. In support of the CCD development and characterization, and to enable an independent assessment of the Euclid CCDs (the procurement of which is ESA’s responsibility), ESA/ESTEC has built a test bench. This test bench allows for a flexible operation and readout of the CCDs, originally for CCD204 and shortly also for CCD273-84. It provides the basic tools for noise and gain calibration, and CTI, QE, MTF and PRNU measurements. In addition, the bench provides scanning spot illumination with a spot size well below the pixel size, for measurement of the intra-pixel response of the CCDs before and after radiation damage. Such measurements are of great importance for the characterization and modeling of the VIS instrument’s PSF, in particular to enable the prediction of the evolution of the PSF shape under the influence of the L2 radiation environment during the mission. This set-up will also allow for simulation of typical Euclid sky images in the lab. The capabilities and validation of this bench at ESA are described in this paper.