A Compact Crystal Positioning System for Neutron Diffraction

When completed, the Spallation Neutron Source¿s (SNS) multiple beam lines will provide unprecedented opportunities to conduct studies in materials characterization, medical isotope production, and the transmutation of nuclear waste. However, to take full advantage of the greatly reduced data collection times made possible by the SNS¿s high neutron flux, new automated sample changers must be developed and deployed. The large goniometers, traditionally used to position samples relative to particle beams, will be incompatible with many of the new SNS instruments. This project will develop a very compact, high-precision manipulator, adjustable in six degrees-of-freedom, which is mounted within the bore of a temperature control cryostat. A kinematic ¿socket¿ will be incorporated into the manipulator, allowing samples to be efficiently loaded and unloaded using industrial robotics. Phase I established feasibility by creating a prototype positioning system, and demonstrating its ability to securely register an incoming sample and to accurately and rapidly adjust its position. The system¿s development was closely coordinated with an SNS instrument scientist and included designs for complementary temperature control and crystal alignment systems. During Phase II, the manipulator¿s design will be refined and fully characterized. A loading robot, tailored to the needs of the Single Crystal Diffractometer, will be developed. The manipulator will be mated with the handling robotics and a temperature control system, and installed in the beam line. Commercial Applications and other Benefits as described by the awardee: The compact crystal positioning system should provide neutron scientists with a powerful enabling technology. Versions of this integrated system could be disseminated to other SNS beamlines and to other neutron science facilities. Applications in other branches of science include X-ray crystallography, fusion research, and electron beam lithography.