High-Dynamic-Range, Rad-Hard, Time-Resolved, Correlated X-ray Photon Detector

The brilliance of the latest generation of synchrotron beam lines enables the possibility of carrying out X-ray photon correlation spectroscopy (XPCS) experiments. Such experiments promise new insights into dynamic phenomena in condensed matter, which occurs at shorter length scales than can be probed by visible light and at longer length scales than can be investigated with the neutron-spin-echo technique. Presently, XPCS cannot be exploited for many of its potential applications because of poor signal-to-noise ratio (SNR). While some gains in the XPCS SNR can be expected from improvements in source brilliance, a more cost-effective approach would involve the optimization of time-correlated photon-counting area detectors. This project will develop a new, fast X-ray, focal plane array (FPA) detector that will provide high-throughput, high sensitivity, time-resolved X-ray scattering and imaging experiments, especially for XPCS. High throughput will be achieved using an event-driven-timestamp (EDTS) asynchronous readout architecture. Each pixel will contain a single X-ray-photon-sensitive photo detector, an energy discriminator, and a comparator that time-stamps the arrival of the photon. To resolve the dynamic range problems of existing XPCS detectors, photon arrival times will be recorded on a pixel-by-pixel basis, and only pixels recording an event will be read out. Commercial Applications and other Benefits as described by the awardee XPCS has the potential to impact many areas of statistical physics and promises access to a variety of important phenomena in soft condensed-matter systems such as polymers, polymer blends, polyelectrolytes, block copolymers, and micellar systems. Further interest should exist in the measurement of rotational and intermolecular relaxation times for stiff and rod-like polymers. Beyond XPCS, the detector should find application in time-resolved X-ray scattering experiments of all sorts.