A framework for modeling the detailed optical response of thick, multiple segment, large format sensors for precision astronomy applications

摘要

Near-future astronomical survey experiments, such as LSST, possess systemrequirements of unprecedented fidelity that span photometry, astrometry andshape transfer. Some of these requirements flow directly to the array ofscience imaging sensors at the focal plane. Availability of high qualitycharacterization data acquired in the course of our sensor development programhas given us an opportunity to develop and test a framework for simulation andmodeling that is based on a limited set of physical and geometric effects. Inthis paper we describe those models, provide quantitative comparisons betweendata and modeled response, and extrapolate the response model to predictimaging array response to astronomical exposure. The emergent picture departsfrom the notion of a fixed, rectilinear grid that maps photo-conversions to thepotential well of the channel. In place of that, we have a situation wherestructures from device fabrication, local silicon bulk resistivity variationsand photo-converted carrier patterns still accumulating at the channel,together influence and distort positions within the photosensitive volume thatmap to pixel boundaries. Strategies for efficient extraction of modelingparameters from routinely acquired characterization data are described. Methodsfor high fidelity illumination/image distribution parameter retrieval, in thepresence of such distortions, are also discussed.