Checking Sample Alignment (for single crystals) in WhiteBeam Mode
Your sample will have been pre-aligned before arriving on Merlin, either on ALF by prior arrangement or at your home institute. On mounting your sample in the sample environment you will have one remaining degree of freedom, the rotation angle about the vertical axis. This can be oriented by running the instrument in white beam mode, such that it acts as a diffractometer. To see your diffraction pattern, we look at the raw data using instrument view within MANTID. By relating the Bragg peak positions in two theta to the rotation stage angle, the orientation of the sample can be determined and modified as necessary. The appearance of Bragg spots can be followed in near real-time by using live streaming, please ask your local contact if this would be of benefit to you.
White beam crystal orientation on Merlin
To convert your .nxs (event) .raw (histogram) data files into nxspe files suitable for viewing using matlab or mantid, the data first need to be reduced using iliad within mantid. An example iliad script to reduce multi-rep data, which will run on an ISIS machine, and some files you may need to run this script, can be found in the related links box to the right.
Viewing powder inelastic neutron data
Historically this has been done using Mslice, but we would now recommend that you use the VATES package within Mantid.
Mantid equivalent of Mslice for powders
Creating sqw files in Horace
Horace provides the generation, visualisation, simulation and fitting of large 4-dimensional datasets obtained by making multiple measurements of a single crystal with varying sample orientation or incident energy. Both matlab-based and Mantid VATES versions exist.
If you wish to analyse your data remotely, then the externally accessible machines are: rutherford.nd.rl.ac.uk and chadwick.nd.rl.ac.uk. For details of how to connect see the excitations group page.