Laue Diffractometer at a Long Pulse Spallation Source

Article type: Research Article

Authors: Ehlers, G. | Mezei, F.

Affiliations: Hahn-Meitner-Institut Berlin, Glienicker Str. 100, D-14109 Berlin, Germany

Note: [] Corresponding author: Tel.: 30-8062-2031, E-mail: mezei@hmi.de

Abstract: The performance of a Laue diffractometer at a Long Pulse Spallation Source is illustrated by an example. The instrument is built at a thermal f = 25 Hz source and uses a neutron guide, which is 70m long, and a wavelength band of 2 Å at the position of the sample. The pulse of 2ms of the source can be chopped to provide a variable resolution of the order δλ/λ = 1–3%. The instrument is suited for the investigation of samples with unit cell volumes of the order of 100–1000 Å3 at a medium time resolution. For an averaged spallation beam power of 5MW the neutron flux at the sample position is estimated to amount to Φ = 3–8 × 107 n cm−2 s−1, depending on the chopper speed. The performance of the instrument is demonstrated by a Monte Carlo simulation technique. Calculations with an idealised model sample focus on the peak-to-background ratio and the ability to resolve Bragg peaks.

Keywords: instruments for neutron scattering, long pulse spallation source, Monte Carlo method, neutron diffraction techniques, neutron sources, time of flight

DOI: 10.1080/10238169708200106

Journal: Journal of Neutron Research, vol. 6, no. 1-3, pp. 173-184, 1997