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DgsAbsoluteUnitsReduction v1¶

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Properties ¶

Name	Direction	Type	Default	Description
InputWorkspace	Input	MatrixWorkspace	Mandatory	The absolute units sample workspace.
InputMonitorWorkspace	Input	MatrixWorkspace		A monitor workspace associated with the absolute units sample workspace
DetectorVanadiumWorkspace	Input	MatrixWorkspace		An absolute units detector vanadium workspace.
DetectorVanadiumMonitorWorkspace	Input	MatrixWorkspace		A monitor workspace associated with the absolute units detector vanadium workspace.
MaskWorkspace	Input	MatrixWorkspace		A masking workspace to apply to the data.
GroupingWorkspace	Input	MatrixWorkspace		A grouping workspace for the absolute units data.
ReductionProperties	Input	string	__dgs_reduction_properties
OutputWorkspace	Output	MatrixWorkspace	Mandatory	The integrated absolute units workspace.
OutputMaskWorkspace	Output	MatrixWorkspace	Mandatory	The diagnostic mask from the absolute units workspace

This algorithm is responsible for taking an absolute units sample and converting it to an integrated value (one value for entire workspace) for that sample. A corresponding detector vanadium can be used in conjunction with the data reduction. The diagram below shows the workflow. The AbsUnitsIncidentEnergy parameter needs to be passed via a property manager since the absolute units sample may have been measured at an energy different from the sample of interest. Parameters in italics are controlled by the instrument parameter file (IPF) unless provided to the algorithm via a property manager. The mappings are given below.

Parameter	IPF Mapping
VanadiumMass	vanadium-mass
AbsUnitsMinimumEnergy	monovan-integr-min
AbsUnitsMaximumEnergy	monovan-integr-max

The last two parameters are used to create a single bin for the Rebin algorithm. The dashed oval parameter, VanadiumRmm, is taken from the atomic information for the molecular mass of Vanadium. The open circle represents detector diagnostic parameters and they are detailed in the table below.

Parameter	IPF Mapping	DetectorDiagnostic Mapping
HighCounts	diag_huge	HighThreshold
LowCounts	diag_tiny	LowThreshold
AbsUnitsLowOutlier	monovan_lo_bound	LowOutlier
AbsUnitsHighOutlier	monovan_hi_bound	HighOutlier
AbsUnitsMedianTestLow	monovan_lo_frac	LowThresholdFraction
AbsUnitsMedianTestHigh	monovan_hi_frac	HighThresholdFraction
AbsUnitsErrorBarCriterion	diag_samp_sig	SignificanceTest

If a detector vanadium is used, the processed sample workspace is multiplied by a factor containing the sample mass (SampleMass), sample molecular mass (SampleRmm) and the cross-section (Scattering XSec) given by: \(\frac{(\sigma^{V}_{incoherent}+\sigma^{V}_{coherent})\times10^{3}}{4\pi}\) with the cross-section units of \(millibarns/steradian\).