W0074
ACTOR – Automated Crystal Transport, Orientation and
Retrieval. A. R. Criswell, J.W. Pflugrath, R. Athay, T.J. Niemeyer, T.L.
Hendrixson, D. Edwards, G.K. Crane, T. Nienaber†, W.
Robertson†, R. Shafer†, Rigaku/MSC, Inc., 9009
New Trails Dr., The Woodlands, TX 77381 and †Oceaneering Space
Systems, 16665 Space Center Blvd., Houston, TX, 77062
A high-throughput, general purpose robotic system has been
developed which transports flash-cooled crystals securely and safely,
automatically mounts the crystals on most goniometers, optically centers the
crystals in the X-ray beam, screens for diffraction quality, collects and
processes diffraction images, recovers and stores the crystals in a liquid
nitrogen dewar. The system is a refinement of the proven ACTOR system from
Abbott Laboratories [1]. Magnetic crystal storage and transport magazines are
designed to hold up to 60 crystals in a standard CP100 dry shipper with easy
access to any of the positions. While designed for robotic use, the magazines
are easy to use manually and offer significant advantages over antiquated
cryovials and canes. The core of the system is a general purpose 5- or 6-axis
programmable robot that allows the system to be used with virtually any
goniometer axis orientation. The unique non-magnetic end-effector securely grips
Hampton magnetic-base pins and places them on a _-Glide goniometer magnet
without the need to move cryosystem nozzle or beam stops. Miniature motors in
the _-Glide goniometer translate the crystal ±3 mm in all directions in as
little as 4 _m increments. All operations are controlled by the software tool,
DIRECTOR, which automates the high-throughput process of selection, centering,
screening, collection and retrieval of crystals. Limited operations, such as
automatic centering and goniometer control, are available through the
CenterStage program. This software tool is designed for laboratories and
beamlines equipped only with the µ-Glide goniometer. The ACTOR system has
been optimized for high-throughput crystallography at synchrotron beamlines and
in the home lab. Recent experiences and testing of the system have led to
improvements to the dewar design and the end effector. In addition, fast
screening methods have been developed for use at synchrotron beamlines, where
exposure times may be greatly reduced compared to the home lab.
[1] Muchmore, S.W., Olson, J., Jones, R., Pan, J., Blum, M.,
Greer, J., Merrick, S.M., Magdalinos, P., & Nienaber, V. (2000) Structure 8,
R243-R246.