Ticket #3167 (closed: fixed)

Opened 9 years ago

Last modified 5 years ago

SANS data weighting -cut out short wavelengths near beam stop

Reported by: Steve Williams Owned by: Steve Williams
Priority: critical Milestone: Iteration 29
Component: Mantid Keywords:
Cc: doucetm@… Blocked By:
Blocking: Tester: Mathieu Doucet

Description

Q1D needs to have two additional optional parameters RadiusCut and WaveCut. Setting these will increase the Q resolution of the results by removing low resoultion data from short wavelength neutrons near the beam stop. These cut offs restrict the wavelength range for each spectrum used to calculate the intensity _and_ the normalisation term.

This must be consistent with what Richard Heenan wrote below, we're using the second formula. This will be clearly documented here: http://www.mantidproject.org/Q1D

So we ignore all neutrons inside a radius Rmin which is a function of wavelength W. See plot in attached spreadsheet.

Say Rmin = Rcut - ( W/Wcut) Rcut

where W is wavelength, and Wcut and Rcut are adjustable parameters in the gui, with defaults set in the user file.

Or for a given pixel at radius R, the first time channel to be included is given by

W = Wcut (Rcut-R)/Rcut

For example with Wcut = 8 Angstrom and Rcut = 160 mm, this gives a min wavelength of 5.95 angstrom at our usual R=41 mm minimum radius, 5 ang at R=60, 3 ang at R=100, zero ang at R=160, -2 angstrom at R=200.

All neutrons are included above Rcut = 160mm and all neutrons above Wcut = 8 angstrom wavelength.

Wcut and Rcut are totally independent of any L/WAV or L/R ranges set.

Attachments

WcutRcut.xls​ (29.5 KB) - added by Steve Williams 9 years ago.

Change History

Changed 9 years ago by Steve Williams

comment:1 Changed 9 years ago by Steve Williams

  • Status changed from new to accepted

comment:2 Changed 9 years ago by Steve Williams

(In [12762]) First go at implementing the cut offs re #3167

comment:3 Changed 9 years ago by Steve Williams

(In [12763]) Thinking about speed ups re #3167

comment:4 Changed 9 years ago by Steve Williams

(In [12814]) Q1D has been updated! re #3167 fixes #3105

comment:5 Changed 9 years ago by Steve Williams

(In [12815]) Update the SANS Python scripts to use the new Q1D and more support for periods re #3167 re #3234

comment:6 Changed 9 years ago by Steve Williams

(In [12818]) Update system tests for the new Q1D re #3167

comment:7 Changed 9 years ago by Steve Williams

(In [12819]) Update system tests for the new Q1D re #3167

comment:8 Changed 9 years ago by Steve Williams

(In [12826]) Update system tests for the new Q1D re #3167

comment:9 Changed 9 years ago by Steve Williams

(In [12832]) Update system tests re #3167

comment:10 Changed 9 years ago by Nick Draper

  • Milestone changed from Iteration 29 to Iteration 30

Accepted and assigned tickets moved at iteration 29 code freeze

comment:11 Changed 9 years ago by Steve Williams

(In [12848]) Fix system tests re #3167

comment:12 Changed 9 years ago by Steve Williams

  • Status changed from accepted to verify
  • Resolution set to fixed
  • Milestone changed from Iteration 30 to Iteration 29

comment:13 Changed 9 years ago by Steve Williams

  • Status changed from verify to reopened
  • Resolution fixed deleted

comment:14 Changed 9 years ago by Steve Williams

  • Status changed from reopened to verify
  • Resolution set to fixed

(In [12889]) Fix a broken loops problem fixes #3167

comment:15 Changed 9 years ago by Mathieu Doucet

  • Status changed from verify to verifying
  • Tester set to Mathieu Doucet

comment:16 Changed 9 years ago by Mathieu Doucet

  • Status changed from verifying to closed

Does what is supposed to do

comment:17 Changed 5 years ago by Stuart Campbell

This ticket has been transferred to github issue ​4014

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