EIGER2 S 16M Detector - Project Summary/Abstract The goal of this proposal is the purchase and installation of a high-performance DECTRIS EIGER2 S 16M pixel array detector for the new microfocus branchline of GEMINI at the Advanced Light Source (ALS). The Berkeley Center for Structural Biology (BCSB) operates six macromolecular crystallography beamlines at the ALS. Its latest undulator-based microfocus beamline, GEMINI, is just starting operation and available to NIH users. BCSB has received funds for the construction of a second microfocus beamline from the same source. Building a second branch that provides a high brightness user-focusable beam down to 15 microns is required to address the national demand for high brightness small-beam crystallography in the United States where existing microfocus beamlines are oversubscribed and demand far exceeds capacity. Addressing this lack of national capacity now is particularly critical, as we prepare for half of the total U.S. synchrotron macromolecular crystallography resources going dark in the near future with the upcoming major upgrade of the Advanced Photon Source and the enormous impact that will have on NIH-funded investigators. Guided by the expertise of the BCSB development team, our beamlines provide state-of-the-art capabilities in automation, software processing, and hardware control; the addition of a large surface area, fast-readout, high-end detector system at GEMINI will complement the qualities of the new GEMINI beamline and allow further development of new techniques in multi- temperature crystallography and synchrotron serial crystallography. Photon counting pixel array detectors are the gold standard in macromolecular crystallography due to their zero noise, high frame rate, excellent point-spread function, and high dynamic range; they have become standard at many national synchrotron facilities throughout the world. These detectors have been critical in the success of many structural biology projects and the latest design by DECTRIS, the EIGER2, have marked improvements on the speed and quantum efficiency of detectors that are available at the ALS. The EIGER2 S 16M has zero deadtime due to its two counters per pixel that enables fine slicing data collection that can reduce radiation damage—especially in multi-temperature experiments. The high dynamic range means both strong and weak reflections can be collected simultaneously, and the large surface area combined with a single pixel point-spread-function allows collection on samples with large unit cells and/or high resolution. These attributes will maximize the success of NIH researchers at GEMINI and allow the BCSB to excel in its commitment to provide our users the highest quality data and the cutting- edge capabilities needed at the modern synchrotron.
