The PERCIVAL soft X-ray imager

Abstract

With the increased brilliance of state-of-the-art Synchrotron radiation sources and the advent of Free Electron Lasers enabling revolutionary science with EUV to X-ray photons comes an urgent need for suitable photon imaging detectors. Requirements include high frame rates, very large dynamic range, single-photon counting capability with low probability of false positives, and (multi)-megapixels. PERCIVAL ("Pixelated Energy Resolving CMOS Imager, Versatile and Large") is currently being developed by a collaboration of DESY, RAL, Elettra and DLS to address this need for the soft X-ray regime. PERCIVAL is a monolithic active pixel sensor (MAPS), i.e. based on CMOS technology. It will be back-thinned to access its primary energy range of 250 eV to 1 keV with target efficiencies above 90%. According to its preliminary specifications, the roughly 10 10 cm 2 , 3520 3710 pixel monolithic sensor will operate at frame rates up to 120 Hz (commensurate with most FELs) and use multiple gains within its 27 m pixels to measure (e.g. at 500 eV) 1 to 10 5 simultaneously-arriving photons. Currently, small-scale front-illuminated prototype systems (160 210 pixels) are undergoing detailed testing with visible-light as well as X-ray photons.