Charge diffusion measurement in fully depleted CCD using X-rays

Abstract

Tight requirements on the Large Synoptic Survey Telescope point spread function (PSF) demand sensor contribution to PSF be both small and well characterized. The sensor PSF is determined by the lateral charge diffusion on the drift path from the CCD window to the gates.Different techniques for charge diffusion characterization have been developed, each with its own systematics and measurement difficulties. A new way to measure charge diffusion using an X-ray source is presented. We demonstrate the effectiveness and limitations of our technique.