HB3AAdjustSampleNorm v1#

Summary#

Adjusts the detector position based on a detector height and distance offset and normalizes with detector efficiency from a vanadium file or workspace, and converts the input to Q-space.

Properties#

Name	Direction	Type	Default	Description
Filename	Input	list of str lists		Input autoreduced detector scan data files to convert to Q-space. Allowed extensions: [‘.nxs.h5’, ‘.nxs’]
VanadiumFile	Input	string		File with Vanadium normalization scan data. Allowed extensions: [‘.nxs’]
NormaliseBy	Input	string	Time	Normalise to monitor, time or None. Allowed values: [‘None’, ‘Time’, ‘Monitor’]
NormalizeData	Input	boolean	True	When False, skip normalization of the output data even if vanadium data is provided.
InputWorkspaces	Input	string		Workspace or comma-separated workspace list containing input MDHisto scan data.
VanadiumWorkspace	Input	IMDHistoWorkspace		MDHisto workspace containing vanadium normalization data
DetectorHeightOffset	Input	number	0	Optional distance (in meters) to move detector height (relative to current position)
DetectorDistanceOffset	Input	number	0	Optional distance (in meters) to move detector distance (relative to current position)
Wavelength	Input	number	Optional	Optional wavelength value to use as backup if one was not found in the sample log
OutputType	Input	string	Q-sample events	Whether to use ConvertHFIRSCDtoQ for an MDEvent, or ConvertWANDSCDtoQ for an MDHisto. Allowed values: [‘Q-sample events’, ‘Q-sample histogram’, ‘Detector’]
ScaleByMotorStep	Input	boolean	False	If True then the intensity of the Q-sample events output will be scaled by the motor step size. This will allow directly comparing the intensity of data measured with different motor step sizes.
MinValues	Input	dbl list	-10,-10,-10	3 comma separated values, one for each q_sample dimension
MaxValues	Input	dbl list	10,10,10	3 comma separated values, one for each q_sample dimension; must be larger than those specified in MinValues
MergeInputs	Input	boolean	False	If all inputs should be merged into one MDEvent output workspace
BinningDim0	Input	dbl list	-8.02,8.02,401	Binning parameters for the 0th dimension. Enter it as acomma-separated list of values with theformat: ‘minimum,maximum,number_of_bins’.
BinningDim1	Input	dbl list	-2.52,2.52,126	Binning parameters for the 1st dimension. Enter it as acomma-separated list of values with theformat: ‘minimum,maximum,number_of_bins’.
BinningDim2	Input	dbl list	-8.02,8.02,401	Binning parameters for the 2nd dimension. Enter it as acomma-separated list of values with theformat: ‘minimum,maximum,number_of_bins’.
Grouping	Input	string	None	Group pixels (shared by input and normalization). Allowed values: [‘None’, ‘2x2’, ‘4x4’]
OutputWorkspace	Output	`Workspace`	Mandatory	Output MDWorkspace in Q-space, name is prefix if multiple input files were provided.
OutputNormalizationWorkspace	Output	`Workspace`		Optional MDEvent output workspace containing the per-file vanadium normalization scaled by the monitor flux ratio. Requires NormalizeData=False, OutputType=’Q-sample events’, and vanadium data. When multiple inputs are provided, MergeInputs must also be True.
OutputGroupingWorkspace	Output	`Workspace`		Optional: output GroupingWorkspace mapping every detector’s workspace index to its group ID. Only produced when Grouping is ‘2x2’ or ‘4x4’.

Description#

Takes in DEMAND detector scan data from files or workspaces and converts them to Q-space, providing an optional adjustment of the detector positions. DetectorHeightOffset adjusts all banks along the y-axis, and DetectorDistanceOffset adjusts banks along the z-axis. Both parameters move the detector relative to the current detector position.

The output can be either an MDEventWorkspace or a MDHistoWorkspace. For a MDHistoWorkspace, the conversion to Q-space is done using ConvertWANDSCDtoQ while ConvertHFIRSCDtoMDE is used for outputting an MDEventWorkspace.

If multiple data file are included then the output will be a WorkspaceGroup containing all the MDWorkspace.

Normalisation#

During loading a few different types of normalisation can be applied, vanadium, time or monitor and motor step size. VanadiumFile or VanadiumWorkspace is applied by dividing the data detector pixel-by-pixel. The NormaliseBy option time or monitor uses that log values from the data (and vanadium if used) input and is applied to each scan axis step. The ScaleByMotorStep scales the entire data by the step size of either the omega or phi axis, this is only applied when OutputType is Q-sample events and allows the comparison of peak intensities found with IntegratePeaksMD to be directly compared between scans measured with different step sizes.

Path to MDNorm#

Setting NormalizeData=False with OutputType=Q-sample events suppresses the division of the data by the vanadium and flux, and instead makes the vanadium-based normalization available as a separate MDEventWorkspace via OutputNormalizationWorkspace. The two workspaces — unnormalized data and normalization — can then be passed to MDNorm, which applies symmetry-correct normalization to an arbitrary Q-sample or HKL binning chosen after data collection. This deferred-normalization workflow avoids rebinning artefacts that arise when the vanadium correction is applied before converting to the final reciprocal-space grid.

When multiple input files are provided, MergeInputs=True must also be set so that the per-file normalization workspaces are merged into a single output alongside the merged data workspace.

Grouping#

A grouping option is available group pixels by either 2x2 or 4x4 which reduces memory usage and improves the performance of subsequent reduction steps. The default is the original detector pixelation.

See HB3AIntegratePeaks for complete examples of the HB3A workflow.

Categories: AlgorithmIndex | Crystal\Corrections

Source#

Python: HB3AAdjustSampleNorm.py