HYBRIDIZED HIGH-Z PIXEL DETECTOR

Recent advances in X-ray technology such as high brilliance, diffraction limited synchrotron light sources enable corresponding advances in a number of important nano-scale X-ray analysis techniques including coherent diffraction imaging, ptychography and X-ray photon correlation spectroscopy. Better X ray detectors are needed to take full advantage of these advances. In particular, imaging detectors with submicron resolution and higher sensitivity at energies greater than 30 keV are needed. Coherent diffraction imaging (CDI), for example, is a revolutionary method of studying micro- and nano-scale materials but it is a time-consuming experimental technique that requires valuable synchrotron beam access. The availability of imaging detectors with better sensitivity to high energy X-rays would provide better data, make more efficient use of valuable beam time and accelerate research. Current X-ray cameras are typically constructed from silicon and are inherently inefficient and need to be supplanted by newer variants better equipped to stop more energetic x-rays. RMD’s approach to solve this problem is to create a hybridized X-ray camera based on a high-Z semiconductor converter layer integrated on a readout circuit. Such an X-ray camera will provide superior detection efficiency for X-ray energies above 30 keV and sub-pixel spatial resolution. In Phase I, two detector technologies, GaAs based diode arrays and TlBr films, were evaluated for integration with CMOS ROIC technologies. Based on the results, we selected TlBr as the most promising approach to pursue in Phase II. The Timepix chip was also identified as an ideal readout technology. The Phase II will concentrate on the production of TlBr semiconductor converter layers. TlBr films will be deposited directly on to the readout chip without need of costly bump bonding. Prototype imaging arrays will be evaluated at an X-ray diffraction facility by our collaborator at UC Berkeley. The primary beneficiaries of this technology will be those who rely on CDI, and potentially other diffraction techniques, to make discoveries in their varied fields. Additionally, the underlying x-ray detection schemes can be applied to fields such as high-resolution medical radiography (mammography) and non-destructive evaluation used in electronics manufacturing.