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DetectorDiagnostic v1¶

Summary ¶

Identifies histograms and their detectors that have total numbers of counts over a user defined maximum or less than the user define minimum.

Properties ¶

Name	Direction	Type	Default	Description
InputWorkspace	Input	MatrixWorkspace	Mandatory	Name of the integrated detector vanadium (white beam) workspace.
HardMaskWorkspace	Input	MatrixWorkspace		A hard mask to apply to the inputworkspace
OutputWorkspace	Output	MatrixWorkspace	Mandatory	A MaskWorkspace containing the masked spectra as zeroes and ones.
StartWorkspaceIndex	Input	number	0	The index number of the first spectrum to include in the calculation (default 0)
EndWorkspaceIndex	Input	number	Optional	The index number of the last spectrum to include in the calculation (default the last histogram)
RangeLower	Input	number	Optional	No bin with a boundary at an x value less than this will be used in the summation that decides if a detector is ‘bad’ (default: the start of each histogram)
RangeUpper	Input	number	Optional	No bin with a boundary at an x value higher than this value will be used in the summation that decides if a detector is ‘bad’ (default: the end of each histogram)
LowThreshold	Input	number	0	Spectra whose total number of counts are equal to or below this value will be marked bad (default 0)
HighThreshold	Input	number	Optional	Spectra whose total number of counts are equal to or above this value will be marked bad (default off)
LevelsUp	Input	number	0	Levels above pixel that will be used to compute the median. If no level is specified, or 0, the median is over the whole instrument.
SignificanceTest	Input	number	0	Error criterion as a multiple of error bar i.e. to fail the test, the magnitude of the difference with respect to the median value must also exceed this number of error bars
LowThresholdFraction	Input	number	0.1	Lower acceptable bound as fraction of median value
HighThresholdFraction	Input	number	1.5	Upper acceptable bound as fraction of median value
LowOutlier	Input	number	0.01	Lower bound defining outliers as fraction of median value
HighOutlier	Input	number	100	Upper bound defining outliers as fraction of median value
CorrectForSolidAngle	Input	boolean	False	Flag to correct for solid angle efficiency. False by default.
ExcludeZeroesFromMedian	Input	boolean	False	If false (default) zeroes will be included in the median calculation, otherwise they will not be included but they will be left unmasked
DetVanCompare	Input	MatrixWorkspace		Name of a matching second detector vanadium run from the same instrument. It must be treated in the same manner as the input detector vanadium.
DetVanRatioVariation	Input	number	1.1	Identify spectra whose total number of counts has changed by more than this factor of the median change between the two input workspaces
SampleTotalCountsWorkspace	Input	MatrixWorkspace		A sample workspace integrated over the full axis range.
SampleBackgroundWorkspace	Input	MatrixWorkspace		A sample workspace integrated over the background region.
SampleBkgLowAcceptanceFactor	Input	number	0	Low threshold for the background check MedianDetectorTest.
SampleBkgHighAcceptanceFactor	Input	number	5	High threshold for the background check MedianDetectorTest.
SampleBkgSignificanceTest	Input	number	3.3	Error criterion as a multiple of error bar i.e. to fail the test, the magnitude of the difference with respect to the median value must also exceed this number of error bars
SampleCorrectForSolidAngle	Input	boolean	False	Flag to correct for solid angle efficiency for background check MedianDetectorTest. False by default.
SampleWorkspace	Input	MatrixWorkspace		A sample workspace. This is used in the PSD Bleed calculation.
MaxTubeFramerate	Input	number	0	The maximum rate allowed for a tube in counts/us/frame.
NIgnoredCentralPixels	Input	number	80	The number of pixels about the centre to ignore.
NumberOfFailures	Output	number

This algorithm is a C++ replacement for the Python diagnostics.diagnose function located in the scripts/inelastic directory. The algorithm expects processed workspaces as input just as the other function did. The main functionality of the algorithm is to determine issues with detector vanadium runs and mask out bad pixels. The algorithms that are run on the detector vanadium are FindDetectorsOutsideLimits v1 and MedianDetectorTest v1. It also performs a second set of diagnostics on another detector vanadium run and DetectorEfficiencyVariation v1 on the two. The algorithm also checks processed sample workspaces (total counts and background) for bad pixels as well. The total counts workspace is tested with FindDetectorsOutsideLimits v1. The background workspace is run through MedianDetectorTest v1. A processed sample workspace can be given to perform and CreatePSDBleedMask v1 will be run on it.

Workflow ¶

Parameters for the child algorithms are not shown due to the sheer number. They are passed onto child algorithms that under the same name, except

LowThreshold and HighThresold are not passed onto FindDetectorsOutsideLimits v1, but are set as 1.0e-10 and 1.0e100 respectively.
LowOutLier, HighOutlier and ExcludeZeroesFromMedian are not passed onto MedianDetectorTest v1, but are set as 0.0, 1.0e100 and true respectively.
DetVanRatioVariation is passed onto DetectorEfficiencyVariation v1 as Variation.
SampleBkgLowAcceptanceFactor, SampleBkgHighAcceptanceFactor, SampleBkgSignificanceTest and SampleCorrectForSolidAngle are passed onto MedianDetectorTest v1 as LowThreshold, HighThreshold, SignicanceTest and CorrectForSolidAngle respectively.

Numerous uses of MaskDetectors v1 are not shown and can be taken be be executed whenever appropriate. Also the output property NumberOfFailures from the executed child algorithms are added together to form the NumberOfFailures output by the main algorithm.