3.5

StripVanadiumPeaks v2

../_images/StripVanadiumPeaks-v2_dlg.png

StripVanadiumPeaks dialog.

Summary

This algorithm removes peaks (at vanadium d-spacing positions by default) out of a background by linearly/quadratically interpolating over the expected peak positions.

Properties

Name Direction Type Default Description
InputWorkspace Input MatrixWorkspace Mandatory Name of the input workspace. If you use the default vanadium peak positions are used, the workspace must be in units of d-spacing.
OutputWorkspace Output MatrixWorkspace Mandatory The name of the workspace to be created as the output of the algorithm. If the input workspace is an EventWorkspace, then the output must be different (and will be made into a Workspace2D).
FWHM Input number 7 The number of points covered, on average, by the fwhm of a peak. Passed through to FindPeaks. Default 7.
Tolerance Input number 4 A measure of the strictness desired in meeting the condition on peak candidates. Passed through to FindPeaks. Default 4.
BackgroundType Input string Linear The type of background of the histogram. Present choices include Linear and Quadratic. Allowed values: [‘Linear’, ‘Quadratic’]
HighBackground Input boolean True Flag to indicate that the peaks are relatively weak comparing to background
PeakPositionTolerance Input number -1 Tolerance on the found peaks’ positions against the input peak positions. A non-positive value turns this option off.
WorkspaceIndex Input number Optional If set, peaks will only be removed from this workspace index (otherwise from all)

Description

  • A list of vanadium peak positions in d-spacing is used for the central peak positions: 0.5044,0.5191,0.5350,0.5526,0.5936,0.6178,0.6453,0.6768,0.7134,0.7566,0.8089,0.8737,0.9571,1.0701,1.2356,1.5133,2.1401
  • StripPeaks is called by providing the list of vanadium peak positions.
  • The vanadium peaks are fit to a function combined from Gaussian and linear/quadratic background.

Usage

Note

To run these usage examples please first download the usage data, and add these to your path. In MantidPlot this is done using Manage User Directories.

Example:

ws = Load("PG3_733.nxs")
wsOut = StripVanadiumPeaks(ws,BackgroundType="Linear",WorkspaceIndex=2)
i = 1529
print "This peak at %.4f Angstroms has been reduced from %.0f to a background level of %.0f" % (wsOut.readX(2)[i],ws.readY(2)[i], wsOut.readY(2)[i])

Output:

This peak at 0.8116 Angstroms has been reduced from 11569 to a background level of 10771

Categories: Algorithms | CorrectionFunctions | Optimization | PeakFinding | Diffraction