This title appears in the Scientific Report : 2015 

A Rietveld refinement method for angular- and wavelength-dispersive neutron time-of-flight powder diffraction data
Jacobs, Philipp
Houben, Andreas / Schweika, Werner / Tchougréeff, Andrei L. / Dronskowski, Richard (Corresponding author)
Streumethoden; JCNS-2
JCNS-FRM-II; JCNS-FRM-II
Projekt Europäische Spallationsquelle (international); ESS
JARA-FIT; JARA-FIT
Streumethoden; PGI-4
Journal of applied crystallography, 48 (2015) 6, S. 1627 - 1636
Copenhagen Munksgaard 2015
10.1107/S1600576715016520
26664340
Journal Article
Jülich Centre for Neutron Research (JCNS)
Materials and Processes for Energy and Transport Technologies
Quantum Condensed Matter: Magnetism, Superconductivity
Controlling Collective States
Controlling Collective States
Others > 0
Restricted
Restricted
Please use the identifier: http://dx.doi.org/10.1107/S1600576715016520 in citations.
Please use the identifier: http://hdl.handle.net/2128/9679 in citations.
This paper introduces a two-dimensional extension of the well established Rietveld refinement method for modeling neutron time-of-flight powder diffraction data. The novel approach takes into account the variation of two parameters, diffraction angle 2[theta] and wavelength [lambda], to optimally adapt to the varying resolution function in diffraction experiments. By doing so, the refinement against angular- and wavelength-dispersive data gets rid of common data-reduction steps and also avoids the loss of high-resolution information typically introduced by integration. In a case study using a numerically simulated diffraction pattern of Rh0.81Fe3.19N taking into account the layout of the future POWTEX instrument, the profile function as parameterized in 2[theta] and [lambda] is extracted. As a proof-of-concept, the resulting instrument parameterization is then utilized to perform a typical refinement of the angular- and wavelength-dispersive diffraction pattern of CuNCN, yielding excellent residuals within feasible computational efforts. Another proof-of-concept is carried out by applying the same approach to a real neutron diffraction data set of CuNCN obtained from the POWGEN instrument at the Spallation Neutron Source in Oak Ridge. The paper highlights the general importance of the novel approach for data analysis at neutron time-of-flight diffractometers and its possible inclusion within existing Rietveld software packages.