Time-Resolved, X-Ray Photon Detector Array

As synchrotron radiation has become a ubiquitous tool across a broad area of forefront science, the DOE supports collaborative research centers for synchrotron radiation science. With advances in the brightness of synchrotron radiation sources, a wide gap has developed between the ability of these sources to deliver high photon fluxes and the ability of detectors to measure the resulting photon, electron, or ion signals. This project will develop a high speed, time-resolved, x-ray photon detector that is based on a monolithic, fully-depleted, back-illuminated, silicon-on-insulator (SOI) CMOS active pixel sensor (APS). The new detector will advance the state-of-the-art in x-ray and beamline imaging, as measured by detection efficiency, count rate, and reliability. Within each pixel are included two 6-bit column-wise, 3-bit pixel local discriminators, and a 4-deep bank of memory for storing 15-bit timestamps. The superior transistor isolation of SOI will allow for continuous digital storage and readout, without affecting the low noise performance of the pixel amplifier. During Phase I, the design of the time-resolved, 1024x1024 format, 20-micron pitch x-ray photon-counting imager will be completed, and prototype circuits will be fabricated. In Phase II, a fully functional imager, optimized for x-ray photon correlation spectroscopy (XPCS) and other x-ray science applications, will be fabricated, and its performance will be demonstrated. Commercial Applications and other Benefits as described by the awardee: In addition to the application for synchrotron radiation, these detectors should find use in star trackers and other space imaging applications. For example, the DoD relies on the celestial reference frame for many purposes, including satellite attitude determination, payload calibration, payload pointing, in-course miSTAXe adjustments, and space surveillance.