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X-ray crystallography is the primary method to determine the 3D structures of complex macromolecules at high resolution. In the years to come, the Advanced Photon Source (APS) and similar 3rd-generation synchrotron sources elsewhere will become the most powerful tools for studying atomic structures of biological molecules. One of the major bottlenecks in the x-ray data collection process is the constant need to change and realign the crystal sample. This is a very time- and manpower-consuming task. An automated sample mounting system will help to solve this bottleneck problem. We have developed a novel robot-based automation system for cryogenic crystal sample mounting at the APS. Design of the robot-based automation system, as well as its on-line test results at the Argonne Structural Biology Center (SBC) 19-BM experimental station, are presented in this paper. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

We discuss the first bench tests of a sample manipulator which was recently designed at SRC for the Scienta 2002 User system. The manipulator concept utilizes the 10° angular window of the Scienta in the horizontal plane (angle dispersion) by rotating the sample normal around the vertical axis while angular scans along the vertical axis (energy dispersion) are continuous within ±30° relative to the electron lens by rotating the sample around the horizontal axis. With this concept it is possible to precisely map the entire two-dimensional k-space of a crystal by means of stitching together 10° wide stripes centered +15° to -50° relative to the sample normal. Three degrees of translational freedom allow positioning the sample surface at the focal point of the analyzer. Two degrees of rotational freedom are available at this position for manipulating the sample. Samples are mounted to a standard holder and transferred to the manipulator via a load-lock system attached to a prep chamber. The manipulator is configured with a cryogenic cold head, an electrical heater, and a temperature sensor permitting continuous closed-loop operation for 20–380 K. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]