Materials science applications of the new National Institute of Standards and Technology powder diffractometer

The new high-resolution neutron powder diffractometer BT-1 at the NIST reactor has proven to be a powerful and versatile instrument in its first year of operation. With 32 detectors arranged at 5 degree intervals and a 12 degree 2θ scan range, powder diffraction patterns can be collected to 167 degree 2θ. There is a choice of three monochromator take-off angles (75 degree, 90 degree, and 120 degree) so that the peak-width minimum can be matched to the d-spacing range that is most important for each sample; all choices have a wavelength close to 1.54 angstrom. Data can be collected on sample sizes ranging from 200 mg to 30 g. Temperatures of 0.3 K to 1,400 K are routinely available, and a magnetic field of 7T can be applied with a superconducting magnet. Typical data collection times range from 1--12 hours depending upon sample size and desired resolution. Examples are given of a variety of materials applications