Överlåtaren: a fast way to transfer and orthogonalize two-dimensional off-specular reflectivity data

Abstract

Reflectivity measurements offer unique opportunities for the study of surfaces and interfaces, and specular reflectometry has become a standard tool in materials science to resolve structures normal to the surface of a thin film. Off‐specular scattering, which probes lateral structures, is more difficult to analyse, because the Fourier space being probed is highly anisotropic and the scattering pattern is truncated by the interface. As a result, scattering patterns collected with (especially time‐of‐flight) neutron reflectometers are difficult to transform into reciprocal space for comparison with model calculations. A program package is presented for a generic two‐dimensional transformation of reflectometry data into q space and back. The data are represented on an orthogonal grid, allowing cuts along directions relevant for theoretical modelling. This treatment includes background subtraction as well as a full characterization of the resolution function. The method is optimized for computational performance using repeatable operations and standardized instrument settings.

Combined specular and off-specular reflectometry: elucidating the complex structure of soft buried interfaces

“…The detector was 3.1 m away from the sample and had a pixel size of 1.2 mm in the relevant direction. SR data were normalized to the incident beam spectrum using COSMOS (Gutfreund et al, 2018), and OSS data were normalized using LAMP (Richard et al, 1996) and transformed into q or p space using Ö verlåteren research papers (Adlmann et al, 2016) if needed for visualization. OSS fitting was done in versus 2 space using the algorithm described here.…”

“…One possibility for qualitative distinction between optical enhancements and physical structure factors is to convert the raw data into different 2D spaces (Adlmann et al, 2016) and look for orthogonal intensity lines in each of them. In order to illustrate this we plotted data obtained from a polymer trilayer system comprising a thin deuterated poly(methy methacrylate) (d-PMMA) film of thickness around 10 nm sandwiched between two layers of hydrogenated polystyrene (h-PS) of thickness around 150 nm (de Silva et al, 2012).…”

Influence of Dimensional Effects on the Curie Temperature of Dy and Ho Thin Films

“…Neutron measurements were performed using a REMUR time-of-flight reflectometer that operates based on an IBR-2M pulse fast reactor available at the Laboratory of Neutron Physics of the Joint Institute for Nuclear Research. Experimental data obtained with the REMUR reflectometer were transformed from the instrumental coordinate system into the reciprocal space coordinate system using Överlåtaren software [20].…”

Recent upgrades of the neutron reflectometer D17 at ILL

“…The combination of the 9.6 Â 10 9 n cm À2 s À1 white-beam flux on the sample and the uniform lateral response of the new detector system makes D17 particularly suited to off-specular studies. The number of experiments explicitly using these capabilities is therefore increasing (Adlmann et al, 2016;Pambou et al, 2016;Maruyama et al, 2016Maruyama et al, , 2017.…”