VesuvioCorrections dialog.
Table of Contents
| Name | Direction | Type | Default | Description |
|---|---|---|---|---|
| InputWorkspace | Input | MatrixWorkspace | Mandatory | Input TOF workspace |
| WorkspaceIndex | Input | number | 0 | Index of spectrum to calculate corrections for |
| FitParameters | Input | TableWorkspace | Table containing the calculated fit parametersfor the data in the workspace | |
| Masses | Input | dbl list | Mandatory | Mass values for fitting |
| MassIndexToSymbolMap | Input | Dictionary | null\n | A map from the index of the mass in the Masses property to a chemical symbol. |
| MassProfiles | Input | string | Mandatory | Functions used to approximate mass profile. The format is function=Function1Name,param1=val1,param2=val2;function=Function2Name,param3=val3,param4=val4 |
| IntensityConstraints | Input | string | A semi-colon separated list of intensity constraints defined as lists e.g [0,1,0,-4];[1,0,-2,0] | |
| HydrogenConstraints | Input | Dictionary | null\n | Constraints used to approximate the intensity of the hydrogen peak in back-scattering spectra for multiple scattering corrections. |
| ContainerWorkspace | Input | MatrixWorkspace | Container workspace in TOF | |
| ContainerScale | Input | number | 0 | Scale factor to apply to container, set to 0 for automatic scale based on linear fit |
| GammaBackground | Input | boolean | True | If true, correct for the gamma background |
| GammaBackgroundScale | Input | number | 0 | Scale factor to apply to gamma background, set to 0 for automatic scale based on linear fit |
| MultipleScattering | Input | boolean | True | If true, correct for the effects of multiple scattering |
| BeamRadius | Input | number | 2.5 | Radius of beam in cm |
| SampleHeight | Input | number | 5 | Height of sample in cm |
| SampleWidth | Input | number | 5 | Width of sample in cm |
| SampleDepth | Input | number | 5 | Depth of sample in cm |
| SampleDensity | Input | number | 1 | Sample density in g/cm^3 |
| Seed | Input | number | 123456789 | |
| NumScatters | Input | number | 3 | |
| NumRuns | Input | number | 10 | |
| NumEvents | Input | number | 50000 | Number of neutron events |
| SmoothNeighbours | Input | number | 3 | |
| CorrectionWorkspaces | Output | WorkspaceGroup | Workspace group containing correction intensities for each correction | |
| CorrectedWorkspaces | Output | WorkspaceGroup | Workspace group containing individual corrections applied to raw data | |
| LinearFitResult | Output | TableWorkspace | Table workspace containing the fit parameters used tolinearly fit the corrections to the data | |
| OutputWorkspace | Output | MatrixWorkspace | Mandatory | The name of the output workspace |
Performs the post fitting corrections steps for Vesuvio data. These steps in include corrections for multiple scattering and gamma.
Example - VesuvioCorrections
###### Simulates LoadVesuvio with spectrum number 135-136 #################
tof_ws = CreateSimulationWorkspace(Instrument='Vesuvio',BinParams=[50,0.5,562],UnitX='TOF')
tof_ws = CropWorkspace(tof_ws,StartWorkspaceIndex=134,EndWorkspaceIndex=135) # index one less than spectrum number
tof_ws = ConvertToPointData(tof_ws)
SetInstrumentParameter(tof_ws, ParameterName='t0',ParameterType='Number',Value='0.5')
SetInstrumentParameter(tof_ws, ParameterName='sigma_l1', ParameterType='Number', Value='0.021')
SetInstrumentParameter(tof_ws, ParameterName='sigma_l2', ParameterType='Number', Value='0.023')
SetInstrumentParameter(tof_ws, ParameterName='sigma_tof', ParameterType='Number', Value='0.3')
SetInstrumentParameter(tof_ws, ParameterName='sigma_theta', ParameterType='Number', Value='0.028')
SetInstrumentParameter(tof_ws, ParameterName='hwhm_lorentz', ParameterType='Number', Value='24.0')
SetInstrumentParameter(tof_ws, ParameterName='sigma_gauss', ParameterType='Number', Value='73.0')
# Algorithm allows separate parameters for the foils
SetInstrumentParameter(tof_ws, ComponentName='foil-pos0', ParameterName='hwhm_lorentz',
ParameterType='Number', Value='144.0')
SetInstrumentParameter(tof_ws, ComponentName='foil-pos0', ParameterName='sigma_gauss',
ParameterType='Number', Value='20.0')
SetInstrumentParameter(tof_ws, ComponentName='foil-pos1', ParameterName='hwhm_lorentz',
ParameterType='Number', Value='144.0')
SetInstrumentParameter(tof_ws, ComponentName='foil-pos1', ParameterName='sigma_gauss',
ParameterType='Number', Value='20.0')
#######################Create dummy fit parameters#############################
params = CreateEmptyTableWorkspace(OutputWorkspace='__VesuvioCorrections_test_fit_params')
params.addColumn('str', 'Name')
params.addColumn('float', 'Value')
params.addColumn('float', 'Error')
params.addRow(['f0.Width', 4.72912, 0.41472])
params.addRow(['f0.FSECoeff', 0.557332, 0])
params.addRow(['f0.C_0', 11.8336, 1.11468])
params.addRow(['f1.Width', 10, 0])
params.addRow(['f1.Intensity', 2.21085, 0.481347])
params.addRow(['f2.Width', 13, 0])
params.addRow(['f2.Intensity', 1.42443, 0.583283])
params.addRow(['f3.Width', 30, 0])
params.addRow(['f3.Intensity', 0.499497, 0.28436])
params.addRow(['f4.A0', -0.00278903, 0.00266163])
params.addRow(['f4.A1', 14.5313, 22.2307])
params.addRow(['f4.A2', -5475.01, 35984.4])
params.addRow(['Cost function value', 2.34392, 0])
masses = [1.0079, 16.0, 27.0, 133.0]
profiles = "function=GramCharlier,hermite_coeffs=[1, 0, 0],k_free=0,sears_flag=1,width=[2, 5, 7];function=Gaussian,width=10;function=Gaussian,width=13;function=Gaussian,width=30"
corrections, corrected, linear_fit, out_ws = VesuvioCorrections(InputWorkspace=tof_ws,
GammaBackground=True,
FitParameters=params,
Masses=masses,
MassProfiles=profiles,
ContainerScale=0.1,
GammaBackgroundScale=0.2)
Categories: Algorithms | Inelastic\Indirect\Vesuvio
Python: VesuvioCorrections.py