High Speed Germanium X-Ray Photon Counting Detector Array

To fully utilize thirdgeneration synchrotron sources, the Xray science community needs advanced detectors that are tailored to beamline science. Detectors are not yet available for the fastest bunch modes, and at the fastest operating modes, collection of multiple bunches is required, laser energy is insufficient at the pulse rates used, and during the longer experiments used to accommodate detector deficits, samples change e.g. through heating. These factors limit the science potential of experiments. A radiationtolerant dualcounting ROIC has been designed especially for the needs of pulse/probe experiments at thirdgeneration synchrotrons. The userenabled and userprogrammable DUPREA ROIC prototype includes in each pixel highbandwidth, lownoise amplification, duallevel pulse discrimination, and dual 15bit counters, allowing twocolor Xray/laser measurements. The counters support integratewhileread operation, minimizing dead time and addressing 11.4 ns and 153 ns bunch rates at the APS. The technology is being optimized to support both silicon and germanium arrays. All the Phase I program objectives were met. A smallformat DUPREA prototype was developed and all its functions were successfully demonstrated, providing proof of concept. Characterization was carried out using test camera electronics and control/UI software developed in Phase I, and the three operating modes were demonstrated at 135 MHz frame rates. Count rate, dynamic range, and linearity were characterized; at the fastest rates, the noise was demonstrated to be 25 electrons RMS. Both silicon and germanium detector arrays were evaluated, and pixelated arrays were hybridized to the prototype. A novel Ge array was completed and characterized, with passivation optimized for low surface leakage. The DUPREA prototype will be enhanced to support a variety of photodetector arrays, and its format increased to 128 128. Pixel preamplifiers will be modified with programmable modes to accommodate various detector arrays. Ge and Si detector arrays will be optimized, prototype detector electronics and mechanics will be reconfigured to meet the user communitys needs, and a cryogenic option will be made available. When the enhanced DUPREA2 camera is available in Phase II, it will be tested at APS. Commercial Applications and Other Benefits: While the Xray detector under development is tailored to the highly specific needs for APS, it has also been developed to be adaptable for other HEP uses as well as a broader range of commercial markets for laboratory instrumentation in industry and academia. The detector architecture is adaptable to spectroscopic applications in the visible and infrared, as well as night vision imaging applications.