Automation of High-Throughput Crystal Screening and Data Collection at SSRL

Abstract

A robotic system for auto‐mounting crystals from liquid nitrogen is now operational on SSRL beamlines (Cohen et al., J. Appl. Cryst. (2002). 35, 720–726). The system uses a small industrial 4‐axis robot with a custom built actuator. Once mounted, automated alignment of the sample loop to the X‐ray beam readies the crystal for data collection. After data collection, samples are returned to the cassette. The beamline Dewar accommodates three compact sample cassettes (holding up to 96 samples each). During the past 4 months, the system on beamline 11‐1 has been used to screen over 1000 crystals. The system has reduced both screening time and manpower. Integration of the hardware components is accomplished in the Distributed Control System architecture developed at SSRL (McPhillips et al., J. Synchrotron Rad. (2002) 9, 401–406). A crystal‐screening interface has been implemented in Blu‐Ice. Sample details can be uploaded from an Excel spreadsheet. The JCSG generates these spreadsheets automatically from their tracking database using standard database tools (http://www.jcsg.org). New diffraction image analysis tools are being employed to aid in extracting results. Automation also permits tele‐presence. For example, samples have been changed during the night without leaving home and scientists have screened crystals 1600 miles from the beamline. The system developed on beamline 11‐1 has been replicated onto 1‐5, 9‐1, 9‐2, and 11‐3 and is used by both general users and the JCSG.