Integrated crystal mounting and alignment system for high-throughput biological crystallography

A sample assembly comprising:

• a. a sample base,
• b. a sample tube, wherein one of two ends of the sample tube is affixed to the sample base;
• c. a sample loop affixed to the other end of the sample tube, wherein
• d. a sample is affixed by the sample loop.

A sample gripper comprising:

• a. a retractable split collet with a collet actuation surface, a collet interior, and a collet recess;
• b. an inner tube, mounted to a gripper flange, which compresses the collet actuation surface upon retraction of the split collet, causing the collet recess to contract upon a sample assembly, thus forcibly retaining the sample assembly;
• c. a shroud tube of larger diameter than the inner tube, forming an outer shroud area between the inner tube and the shroud tube;
• and
• d. a plurality of small openings in the gripper flange connecting to a port, communicating a flow from the port to the inner shroud area;
• wherein a warm dry gas can be applied to the port to keep frost from forming on the inner tube and the split collet, and a gage vacuum can be applied to the port to force liquid nitrogen into the collet interior when the outer shroud area is immersed in liquid nitrogen.

A method of positioning a sample at a predetermined point in space comprising:

• a. establishing a focused video display of a backlit sample with an electronic camera,
• b. establishing a software reference for a predetermined point in space through which an x-ray beam passes,
• c. aligning a cursor to the apparent center of the backlit sample on the video display,
• d. moving the backlit sample to the software reference point,
• e. rotating the backlit sample through an axis non-collinear with the x-ray beam,
• f. repeating said aligning, moving and repeating sequence until the backlit sample undergoes rotations essentially about the software reference point.