Add algorithm to normalise compton scattering spectrum by hydrogen peak area

[Martyn Gigg]

This will require two new algorithms:

1. ConvertToYSpace -

The required conversion is defined by equation (7) in this paper: ​http://link.aip.org/link/doi/10.1063/1.3561493?ver=pdfcov. As the mass & detector delay time are required to calculate Y we cannot simply add a new unit for ConvertUnits. The algorithm will have a single input, the mass and all other parameters: l1,l2,theta,efixed,t0 will be required to be attached to the workspace instrument.

2. NormaliseByPeakArea -

This will use the above algorithm to convert the input TOF spectrum to yspace & then Fit the peak defined by the input mass value. The input data will then be normalised by the fitted peak area value.

[Martyn Gigg]

Basic structure for ConvertToYSpace algorithm

Refs #8598

Changeset: f7b330be5b3b8d144a1e2f9d3e5df2576f179104

[Martyn Gigg]

Refactoring to avoid code duplication.

• getComponentParameter is now only defined in ConvertToYSpace
• DetectorParams struct has moved to ConvertToYSpace
• Y calculation has moved to ConvertToYSpace

Refs #8598

Changeset: 06606cc87c57f610512cb29b61537f57ef9ebdd8

[Martyn Gigg]

Tidy up in ConvertToYSpace and implement exec test

Refs #8598

Changeset: 4287d1f3f285c6796f16c4c357c205a1641d940f

[Martyn Gigg]

Set units on output workspace.

Refs #8598

Changeset: cc054f995a23a612b2c3f9dee2cd88c45846fee8

[Martyn Gigg]

Implement a profile function to fit a mass peak in Y-space.

Used in neutron compton scattering to Fit a spectrum using only the proton peak. Refs #8598

Changeset: 6c9b13e71e5c8b07939990cdf4faec8c1a0ed67f

[Martyn Gigg]

Start of NormaliseByPeakArea algorithm

Refs #8598

Changeset: d3a554670c218be64ba0f002bcac2db40e9312e6

[Martyn Gigg]

Refactor test helper to allow multiple spectra.

Refs #8598

Changeset: 0e5969b9890b5db3aa7721bd9d368bdafb8e1381

[Martyn Gigg]

Symmetrised output is correct for non-sum behaviour

Refs #8598

Changeset: 343b03de957e2a3b5ee999ede90bced6b733d1e2

[Martyn Gigg]

Implement summing behaviour in NormaliseByPeakArea.

Refs #8598

Changeset: 9eb98715068602cbe5a3cdb020a6c8d4288d47f3

[Martyn Gigg]

Fix default value of test helper create2DWorkspaceWithFullInstrument

Accidentally changed the behaviour that everyone else was expecting. Refs #8598

Changeset: 28d9a8859d736d23dc8da108243cb98d93930946

[Martyn Gigg]

Fix silly unit test mistake.

Refs #8598

Changeset: 8a0bfebef6515ca81f682e855a29cc718467db19

[Martyn Gigg]

Fix system VesuvioFitting tests.

Converting the TOF from seconds to microseconds and then back seems to have caused instability in the fitting when including the background. It is actually more sensible to have convertToYSpace take the time in seconds anyway. Refs #8598

Changeset: ba48d4c771b60c7ce6d7289d5b7a39c6c0c5ee78

[Martyn Gigg]

Branch: feature/8598_convert_to_yspace

Tester: First check that the system tests are passing.

The required data for the tests is on the ISIS archive in EVS cycle 09_1 & the IP file is attached to #8378.

from mantid.simpleapi import *

LoadVesuvio(Filename='14188-14195',OutputWorkspace='test_nosum',
            SpectrumList='135-142',Mode='SingleDifference',
            InstrumentParFile=r'IP0004_10.par')
CropWorkspace(InputWorkspace='test_nosum',OutputWorkspace='test_nosum',
              XMin='50',XMax='562')
NormaliseByPeakArea(InputWorkspace='test_nosum',Mass='1.0079',Sum=False,
                    OutputWorkspace='norm', YSpaceDataWorkspace='yspace',
                    FittedWorkspace='fitted',SymmetrisedWorkspace='sym')

Run the following script. It should produce 4 workspaces:

• yspace, fitted and sym should all be in units of A^-1
• norm should be in units of tof

Plot spectrum 135 from yspace, fitted & sym on 1 plot. It should look like the attached image from the VMS manual with the exception that there is an additional peak between approx [-27,-24]A^-1 that we chose not to exclude here.

Now plot spectrum 135 on both test_no_sum & norm. You should find that the norm workspace has the same features as test_nosum and test_nosum ~ 60.177*norm (to within expected precision)

[Martyn Gigg]

Fix cppcheck scope error.

Refs #8598

Changeset: 16710a8cdceb9b5bc30b274110564500f690f937

[Martyn Gigg]

Fix doxygen warning.

Refs #8598

Changeset: 3a534b82c2899d15f8ab8c7156901185683b9a35

[Martyn Gigg]

Put back accidentally removed variable.

Refs #8598

Changeset: d43bfcb8fcb4036afd77b59c7787c795ea26d93d

[Samuel Jackson]

Merge remote-tracking branch 'origin/feature/8598_convert_to_yspace'

Full changeset: ​5cfc6fbd16d17cc500df15b2039be3607b4010e8

[Samuel Jackson]

Checked that everything mentioned in the testing description appears to work as expected. Plots match as in description. Checked that input workspace is approx. 60.177*norm. System tests are passing and code review looks good.

[Stuart Campbell]

This ticket has been transferred to github issue ​9442