Interoperable Data Treatment Software: Part 2
For QENS, INS and modelling of neutron and muon experiments
QENS – Mantid
Quasi-elastic Neutron Scattering (QENS) can be used to study diffusion of molecules but up until now there has been a high level of dissatisfaction from neutron scattering users for the existing solutions of fitting QENS data. Luckily, thanks to ISIS, Mantid has had some functionality for QENS analysis since 2012. SINE2020 has enabled QENS expertise from ISIS, in the form of Sanghamitra Mukhopadhyay, Anthony Lim, Robert Applin, Brandon Hewer, Spencer Howells and Anders Markvardsen, to develop this.
The initial capability of the QENS analysis interface within Mantid was only for instruments at ISIS. With the help of SINE2020 this capability has been upgraded to make analysis independent of instrument parameters so that the interface is applicable for any instrument.
More features, models and functionalities have been implemented to enable users to analyse complicated spectrum using both GUI and scripting modes. Simultaneous fitting allows users to fit several spectra obtained from different instruments with different resolutions and instrument parameters at the same time. This is a clear advantage for analysing complicated samples measured on different equipment.
There now exists an interoperable QENS library of fitting models that can be used by different programs and applications, and a new Mantid GUI to create a more user-friendly interface. This open source addition to Mantid also comes with tutorials and an online user guide for users. Mantid version 4.1 is now available.
ATOMISTIC MODELLING –abINS and MDANSE
A plug-in algorithm for Mantid, called abINS, enables users to calculate inelastic neutron scattering (INS) spectra directly comparable with experiments from lattice dynamics simluations done by external density functional theory (DFT) programs. This has been developed from scratch by Sanghamitra Mukhopadhyay at ISIS partly through SINE2020. Within this algorithm it is also possible to interpret experimental data atomistically by generating individual atom projected INS obtained from the simluations. This algorithm also has the capability to separate out overtones and combination bands from the fundamental modes, which is a huge advantage of analyzing experimental INS spectrum. The latest version was released in Mantid version 4.1.
MDANSE (Molecular Dynamics Analysis for Neutron Scattering Experiments) is also another application compatible with Mantid developed to interactively analyze molecular dynamics simulations. The latest version 1.3.0 was released in February 2019, developed by Remi Perenon at ILL.
MUON SPECTROSCOPY – MUESR and DFT
MUESR and DFT methods have been developed for analyzing data from muon spectroscopy in a joint collaboration between ISIS and the University of Parma. These programmes are interoperable with Mantid and come with supporting documents. You can read more about this work in our article.
Acknowledgements: Thomas Holm Rod, ESS DMSC, Anders Markvardsen and Sanghamitra Mukhopadhyay, ISIS