Monte Carlo simulation of the new time-of-flight powder diffractometer EXED at the Hahn-Meitner-Institut

Article type: Research Article

Authors: Lieutenant, K.^; | Peters, J. | Mezei, F.^;

Affiliations: Hahn-Meitner-Institut Berlin, Glienicker Street 100, D-14109 Berlin, Germany | Institut Laue-Langevin, 6 rue Jules Horowitz, F-38042 Grenoble, France | Los Alamos National Laboratory, LANSCE, Los Alamos, NM 87545, USA

Note: [] Corresponding author. Tel: + 49-30-8062-3068. Fax: + 49-30-8062-2523. Email: peters@hmi.de

Abstract: The new diffractometer EXED at HMI designed for high resolution and extreme environments (like very high magnetic fields) has been simulated in detail using the software package VITESS. The simulation includes the beam extraction system, beam splitter, kink, chopper system, sample and detector. Many parameters like coatings, kink angle, etc. were varied to improve the instrument. The chopper system was checked and a focussing guide optimized. Finally, powder diffraction patterns of an aluminium sample show that a resolution of Δd/d < 2 × 10−4 will be feasible at 176° detector angle. The data collection time is estimated on the basis of the simulation results for the flux at sample.

Keywords: MC simulation, Time-of-flight, Diffractometer, Extraction system, Bi-spectral moderator, Focussing system

DOI: 10.1080/10238160600766294

Journal: Journal of Neutron Research, vol. 14, no. 2, pp. 147-165, 2006