The Low-Q Diffractometer at the Los Alamos Neutron Scattering Center

Abstract

The Low-Q Diffractometer at the Los Alamos Neutron Scattering Center is now operational, and a variety of calibration experiments have been performed. A description of the instrument is presented, emphasizing its special and unique features. In particular, the “dynamic gravity focusing” device has been demonstrated to extend the useful wavelength range to values which would otherwise fall below the beam stop onto the detector. The downstream monitor in the beam stop has also been demonstrated, allowing data reduction even from strongly scattering samples without the necessity of a separate transmission measurement. Examples of data as displayed to users during data acquisition from various experiments shown. Procedures to combine data from a wide wavelength range into Q space are discussed, and three examples are shown which illustrate the dynamic range of the instrument.