\(\renewcommand\AA{\unicode{x212B}}\)
Table of Contents
Name | Direction | Type | Default | Description |
---|---|---|---|---|
InputWorkspace | Input | MatrixWorkspace | Name of data workspace containing the diffraction pattern in .prf file. | |
WorkspaceIndex | Input | number | 0 | Spectrum (workspace index starting from 0) of the data to refine against in input workspace. |
SeqControlInfoWorkspace | InOut | TableWorkspace | Name of table workspace containing sequential refinement information. | |
InputProfileWorkspace | Input | TableWorkspace | Name of table workspace containing starting profile parameters. | |
InputBraggPeaksWorkspace | Input | TableWorkspace | Name of table workspace containing a list of reflections. | |
InputBackgroundParameterWorkspace | Input | TableWorkspace | Name of table workspace containing a list of reflections. | |
StartX | Input | number | 0 | Start X (TOF) to refine diffraction pattern. |
EndX | Input | number | 0 | End X (TOF) to refine diffraction pattern. |
FunctionOption | Input | string | Refine | Options of functionality. Allowed values: [‘Setup’, ‘Refine’, ‘Save’, ‘Load’] |
RefinementOption | Input | string | Random Walk | Options of algorithm to refine. Allowed values: [‘Random Walk’] |
ParametersToRefine | Input | str list | List of parameters to refine. | |
NumRefineCycles | Input | number | 1 | Number of refinement cycles. |
ProfileType | Input | string | Type of peak profile function. Allowed values: [‘’, ‘Neutron Back-to-back exponential convoluted with pseudo-voigt’, ‘Thermal neutron Back-to-back exponential convoluted with pseudo-voigt’] | |
BackgroundType | Input | string | Type of background function. Allowed values: [‘’, ‘Polynomial’, ‘Chebyshev’, ‘FullprofPolynomial’] | |
FromStep | Input | number | -1 | If non-negative, the previous code is not set from last step, but the step specified. |
OutputProjectFilename | Input | string | Name of sequential project file. Allowed extensions: [‘.nxs’] | |
InputProjectFilename | Input | string | Name of sequential project file. Allowed extensions: [‘.nxs’] | |
ProjectID | Input | string | Project ID. |
The purpose of this algorithm is to provide users a tool to control the workflow to refine powder diffractometer’s peak profile. For Time-Of-Flight powder diffractometers in SNS, back-to-back exponential convoluted with pseudo-voigt profile functions are used. The function is complicated with strong correlated parameters. Thus, the refinement on these parameters contains multiple steps, within each of which only a subset of profile parameters are refined.
In order to control the workflow, there are four major functions supported by this algorithm
- Setup : set up a few workspaces that will be used to refine profile parameters in multiple steps;
- Refine : select a subset of peak parameters and do Le Bail fit on them;
- Save : save the current refinement status and refinement history to a project file;
- Load : set up a few workspaces used for refining by loading them from a previously created project file.
- InputWorkspace : data workspace containing the diffraction pattern to refine profile parameters with;
- SeqControlInfoWorkspace : table workspace used to track refinement. Below is the introduction on the fields/columns of this workspace.
- InputProfileWorkspace : table workspace contraining starting values of profile parameters;
- InputBraggPeaksWorkspace : table workspace containing the Bragg peaks’ information for Le Bail fit;
- InputBackgroundParameterWorkspace : table workspace containing the background parameters’ value
- Neutron Back-to-back exponential convoluted with pseudo-voigt : Fullprof profile 9 and GSAS TOF profile 3;
- Thermal neutron Back-to-back exponential convoluted with pseudo-voigt: Fullprof profile 10 (a.k.a. Jason Hodges function).
This is just a brief description for how to use this algorithm.
Categories: AlgorithmIndex | Diffraction\Fitting
Python: RefinePowderDiffProfileSeq.py (last modified: 2020-03-27)