Development of Monolithic CMOS Detectors as x-ray Imaging Spectrometers

We present preliminary results from our ongoing program to develop CMOS detectors as single photon counting, soft X-ray imaging spectrometers. The Smithsonian Astrophysical Observatory in collaboration with SRI International/Sarnoff has been developing monolithic CMOS detectors optimized for x-ray astronomy. Our latest detector consists of an array of 1k x 1k 16 mu m pixels manufactured on 15 mu m epitaxial Si. These detectors are designed to be packaged and thinned for back illumination. The devices have on-chip CDS and are optimized to have high (similar to 40 frame/sec) read-out rates. Such monolithic CMOS imaging sensors would be ideal candidate detectors for the focal planes of space-borne soft x-ray astronomy missions. The high through-put, low noise and excellent low energy response, provide high dynamic range and good time resolution; bright and time varying x-ray features could be temporally and spectrally resolved without saturation or photon pile-up.