.. algorithm::

.. summary::

.. relatedalgorithms::

.. properties::

Description
-----------

Integrates SCD peaks with a range of radii, in order to plot graphs of
the integrated intensity vs radius. This can be useful to determine the
correct integration radius for each peak.

.. figure:: /images/PeakIntensityVsRadius_fig.png
   :alt: {Integrated peak intensity vs integration radius for 3 SCD peaks}


The algorithm requires a :ref:`MDWorkspace <MDWorkspace>` of SCD data in
reciprocal space; generated by e.g.
:ref:`algm-ConvertToDiffractionMDWorkspace`.
Also, you will need a :ref:`PeaksWorkspace <PeaksWorkspace>` as the list of
peaks to integrate. This can be generated using
:ref:`algm-FindPeaksMD`, for example.

The output will be a :ref:`Workspace2D <Workspace2D>` with one spectrum per
peak, where:

-  X = peak radius
-  Y/E = integrated intensity and error for the corresponding radius.
-  Each peak is labeled with a string with "H K L". Use
   :ref:`algm-IndexPeaks` to automatically find HKL values for
   peaks.

This algorithm calls :ref:`algm-IntegratePeaksMD` repeatedly,
with the following parameters filled in:

-  **PeakRadius** = the radius, ranging from RadiusStart to RadiusEnd in
   NumSteps steps.
-  **BackgroundInnerRadius** = radius \* BackgroundInnerFactor *OR*
   BackgroundInnerRadius
-  **BackgroundOuterRadius** = radius \* BackgroundOuterFactor *OR*
   BackgroundOuterRadius

Usage
-----

**Example - PeakIntensityVsRadius:**

The code itself works but disabled from doc tests as takes too long to complete. User should provide its own
event nexus file instead of **TOPAZ_3132_event.nxs** used within this example. The original **TOPAZ_3132_event.nxs**
file is available in `Mantid system tests repository <https://github.com/mantidproject/systemtests/tree/master/Data/TOPAZ_3132_event.nxs>`_.

.. code-block:: python

    # Load a SCD data set from systemtests Data and find the peaks
    LoadEventNexus(Filename=r'TOPAZ_3132_event.nxs',OutputWorkspace='TOPAZ_3132_nxs')
    ConvertToDiffractionMDWorkspace(InputWorkspace='TOPAZ_3132_nxs',OutputWorkspace='TOPAZ_3132_md',LorentzCorrection='1')
    FindPeaksMD(InputWorkspace='TOPAZ_3132_md',PeakDistanceThreshold='0.15',MaxPeaks='100',OutputWorkspace='peaks')
    FindUBUsingFFT(PeaksWorkspace='peaks',MinD='2',MaxD='16')
    IndexPeaks(PeaksWorkspace='peaks')

    # Run the PeakIntensityVsRadius algorithm, where the background shell scales with the PeakRadius
    PeakIntensityVsRadius(InputWorkspace='TOPAZ_3132_md',PeaksWorkspace='peaks',
        RadiusStart=0.00, RadiusEnd=0.15, NumSteps=51,
        BackgroundInnerFactor=1.5,BackgroundOuterFactor=2,
        OutputWorkspace='peak_vs_rad')

    # Run the PeakIntensityVsRadius algorithm, with fixed background shell radius
    PeakIntensityVsRadius(InputWorkspace='TOPAZ_3132_md',PeaksWorkspace='peaks',
        RadiusStart=0.00, RadiusEnd=0.15, NumSteps=51,
        BackgroundInnerRadius=0.15,BackgroundOuterRadius=0.2,
        OutputWorkspace='peak_vs_rad_fixed')

    # Plot a few of the peaks
    plotSpectrum('peak_vs_rad', [0,2,3], error_bars=True)

.. categories::

.. sourcelink::