Efficient Large-area X-ray Detectors

High energy (30-90 keV) x-rays are critical for exploring failure modes of lightweight structural materials and for determining the details on atomic bonding in crystalline materials being developed for catalytic and energy storage applications. Detectors for the x-ray diffraction patterns from these high-energy x-rays must have a combination of good efficiency and good spatial resolution. Current technology, based on scintillators or silicon detectors is limited in spatial resolution and efficiency. We have developed processes for growing polycrystalline mercuric iodide films directly onto readout chips, providing a direct-converter semiconductor x-ray detector with good efficiency and excellent spatial resolution, and with reasonable cost for large-area devices. This Small Business Innovation Research Phase I project will continue the development of x-ray detector technology that has the attributes necessary for high- energy x-ray diffraction analysis. In Phase I we will refine the existing coating technology to improve the spatial resolution, uniformity, and signal to noise ratio and evaluate the coating on both our own integrating-signal small-area chip (2 cm2) and the photon-counting Timepix chip (2 cm2) and choose the best performing device. In Phase II we will test the system at the Stanford Synchrotron Radiation Lightsource (SSRL) in realistic x-ray diffraction studies and develop and market a large-area detector system. Commercial Applications and Other Benefits: The technology we will develop in this Phase I SBIR will meet the specific requirements expressed in the topic description and will be a commercial product available for use at all beam line facilities worldwide that produce x-ray diffraction studies. The device would also compete with current commercially available low-energy x-ray detectors used in for example protein crystallography studies. The detector we develop will also have potential for use in medical imaging applications that require high resolution and real-time imaging capabilities, such as planar x-ray imaging of the beating heart and mammography.