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SavePolarizedNXcanSAS v1¶

Summary ¶

Save a Group Workspace with reduced SANS polarized data in NXcanSAS Format.

Properties ¶

Name	Direction	Type	Default	Description
InputWorkspace	Input	Workspace	Mandatory	The input workspace, which must be in units of Q. Can be a 1D or a 2D workspace.
Filename	Input	string	Mandatory	The name of the .h5 file to save. Allowed extensions: [‘.h5’]
RadiationSource	Input	string	Spallation Neutron Source	The type of radiation used. Allowed values: [‘Spallation Neutron Source’, ‘Pulsed Reactor Neutron Source’, ‘Reactor Neutron Source’, ‘Synchrotron X-ray Source’, ‘Pulsed Muon Source’, ‘Rotating Anode X-ray’, ‘Fixed Tube X-ray’, ‘neutron’, ‘x-ray’, ‘muon’, ‘electron’]
DetectorNames	Input	string		Specify in a comma separated list, which detectors to store information about; where each name must match a name given for a detector in the [[IDF\|instrument definition file (IDF)]]. IDFs are located in the instrument sub-directory of the Mantid install directory.
Transmission	Input	MatrixWorkspace		The transmission workspace. Optional. If given, will be saved at TransmissionSpectrum
TransmissionCan	Input	MatrixWorkspace		The transmission workspace of the Can. Optional. If given, will be saved at TransmissionSpectrum
SampleTransmissionRunNumber	Input	string		The run number for the sample transmission workspace. Optional.
SampleDirectRunNumber	Input	string		The run number for the sample direct workspace. Optional.
CanScatterRunNumber	Input	string		The run number for the can scatter workspace. Optional.
CanDirectRunNumber	Input	string		The run number for the can direct workspace. Optional.
BackgroundSubtractionWorkspace	Input	string		The name of the workspace used in the scaled background subtraction, to be included in the metadata. Optional.
BackgroundSubtractionScaleFactor	Input	number	0	The scale factor used in the scaled background subtraction, to be included in the metadata. Optional.
Geometry	Input	string	Unknown	The geometry type of the collimation. Allowed values: [‘Cylinder’, ‘FlatPlate’, ‘Flat plate’, ‘Disc’, ‘Unknown’]
SampleHeight	Input	number	0	The height of the collimation element in mm. If specified as 0 it will not be recorded.
SampleWidth	Input	number	0	The width of the collimation element in mm. If specified as 0 it will not be recorded.
SampleThickness	Input	number	0	The thickness of the sample in mm. If specified as 0 it will not be recorded.
InputSpinStates	Input	string		The order of the spin states in the input group workspace: +1 Polarization parallel to polarizer, -1 antiparallel and 0 no polarization
PolarizerComponentName	Input	string		The name of the Polarizer Component as defined in the IDF. i.e. ‘short-polarizer’
AnalyzerComponentName	Input	string		The name of the Analyzer Component as defined in the IDF. i.e. ‘helium-analyzer’
FlipperComponentNames	Input	string		Comma separated list of flipper components as defined in the IDF i.e. ‘RF-flipper
MagneticFieldStrengthLogName	Input	string		The name of sample logs in which the magnetic field strength is stored
MagneticFieldDirection	Input	string		Direction of the magnetic field on the sample: comma separated vectorwith three values: Polar, Azimuthal and Rotation angles

Description ¶

Saves a workspace with momentum transfer units into a file adhering to the NXcanSAS format specified by NXcanSAS Data Formats Working Group schema.

This algorithm in particular, adheres to the WIP proposal to update the format to include reduced SANS polarized data.

The algorithm is an extension of SaveNXcanSAS v1, all the metadata available in SaveNXcanSAS v1 can be saved here too.

The InputWorkspace property must be a Workspace Group containing as many members as measured polarization states, which typically would be 2 members for half-polarized SANS measurements and 4 members for full-polarized SANS.

The spin states are set through the InputSpinStates property, every polarization configuration is defined as a PinPout pair, with the possible values for each spin state before (Pin) or after (Pout) the sample being “+1”, “-1” or “0” as defined in the proposal. There must be as many PinPout pairs as workspace members in the InputWorkspace property, in the same order of polarization as that on the workspaces. For example, a full polarized measurement could be defined in the InputSpinStates property as “+1+1,-1+1,-1-1,-1-1” , with “-1-1” and “+1+1” being the non spin-flip configurations and “-1+1 , +1-1” the spin-flip ones.

In addition, the magnetic field strength can be added by referring to the sample log of the InputWorkspace containing the data in MagneticFieldStrengthLogName, the direction of the magnetic field in spherical coordinates is specified in the MagneticFieldDirection property by setting the dimensions of the spherical vector (polar, azimuthal, rotation angles) as comma separated values.

The information for the polarizing components (polarizer, flippers, analyzer) must be specified in PolarizerComponentName, FlipperComponentNames, AnalyzerComponentName properties by writing the polarizer component name as defined in the corresponding Instrument Definition File (IDF). For each component; name, type and distance to sample will be written in the the corresponding dataset. If there is more than one flipper, they can be added by their IDF component name as comma separated lists in the FlipperComponentNames property.

Usage ¶

Example

#Create sample workspace group with simple test data and adding ZOOM instrument.
names = []
for n in range(4):
    name = f"out_{n}"
    CreateSampleWorkspace(OutputWorkspace=name, Function="User Defined", UserDefinedFunction=f"name=Lorentzian, Amplitude=1000, PeakCentre={n+1}, FWHM=1", XUnit="MomentumTransfer", NumBanks=1, BankPixelWidth=1, XMin=0, XMax=16.5, BinWidth=0.1)
    LoadInstrument(name,InstrumentName="ZOOM", RewriteSpectraMap=False)
    names.append(name)

group = GroupWorkspaces(names)
SavePolarizedNXcanSAS(group, "test_file", InputSpinStates="+1-1,-1-1,+1+1,-1+1")