A perfect match for high resolution neutron powder diffraction: Position sensitive detection and focusing monochromators

• Published in: Physica. B, Condensed matter Vol. 241; pp. 237 - 239
• Main Authors: Yelon, W.B, Berliner, R, Popovici, M
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.1997
• Subjects: Bert crystal monochromators; Neutron powder diffraction; Position sensitive detection; Bert crystal monochromators; Position sensitive detection; Neutron powder diffraction
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/S0921-4526(97)00562-0

Position sensitive detectors (PSDs) have been in use at MURR for nearly 20 years, while focusing monochromators have been developed only during the past six years. Incremental improvements in both systems have led to a high resolution powder diffraction system with a fast data acquisition rate for small samples (typically one gram of material). This is achieved by matching sample size to detector spatial resolution, by focusing in real space (two dimensional) and focusing in scattering with bent silicon monochromators. Fully open beams and large area detectors make the performance of this method superior to the conventional one with soller collimators and flat mosaic monochromators (vertically focusing). The use of inexpensive perfect Si crystals and linear position sensitive elements as well as the elimination of multiple Soller slit assemblies also make this an extremely economical alternative. Improvements in electronics, data acquisition software and new, doubly focusing devices have opened the door to widespread use of high resolution powder diffraction at small and medium flux facilities.