SANS: Beam centre HAB algorithm

[Anders Markvardsen]

Having control over the beam centre of the front detector on LOQ and SANS2D is and will be handle differently, because SANS2D front detector is very moveable, and is different from the LOQ HAB's detector.

At the moment the moveable position of the SANS2D front is handled.

However, there is no handling of the beam centre of the LOQ HAB's detector.

The handling of this beam centre should be done in the same way as the rear detectors of both SANS2D and LOQ.

The user experience is that the left panel of the Geometry tab changes to something like:

Rear detector (mm) ( 234 5240 ) tickbox

Front detector (mm) ( 423 2342 ) tickbox

where one and only one of the tickbox are ticked (perhaps use radio buttons here instead) and centre of that detector is found when the Run button is clicked. Further when SANS2D data are loaded the Front detector tickbox must be greyed off and the coordinates displayed are the x and y coordinates of the front detector.

[Nick Draper]

Moved to milestone 2.4

[Gesner Passos]

The implementation of this ticket requires also to extend the files defined in the user script, as described in User file Commands. The SET CENTRE command will change to:

SET CENTRE/MAIN X Y X_PIXEL_DIMENSION Y_PIXEL_DIMENSION
SET CENTRE/HAB  X Y X_PIXEL_DIMENSION Y_PIXEL_DIMENSION

For compatibility reason, SET CENTRE X Y X_PIX Y_PIX will be still valid and will refer to SET CENTRE/MAIN command.

tester: the wiki page must be corrected as well.

tester: After loading the 'User File', the Beam Centre group box, inside the Geometry tab must reflect the values of the defined centre.

[Gesner Passos]

A good file to show the BeamFinder for the HAB detector is the run 74466 -> cycle_12_4.

[Gesner Passos]

SANS: BeamCentre support for high angle detectors bank

re #5942

• SANSRunWindow.ui: Add widgets inside Geometry Tab that allows to show/edit the centre for the high/low angle bank.
• SANSRunWindow.cpp: Interact with the changes in SANSRunWindow and also with the changes in the script in order to support both detectors.
• isis_reducer.py: The changes made here is to support the definition of the centre for both detectors, allowing to get its position get_beam_center and to define their positions. It does extend the class Sample to allow reloading the data to move the detector bank component to the correct position in order to apply the reduction.
• isis_reduction_steps: Extend parsing the USER FILE, in order to accept the commands: SET CENTRE/[MAIN/HAB].
• ISISCommandInterface.py: Adapt the FindBeamCentre method to support both detectors, adapt the WavRangeReduction to reload the dataset for moving the hab detector to its center in order to correct use this parameter for the reduction. Extends the method SetCentre. Changeset: bab290eb5b68fad8f6ef9209d9987a8e961d4da6

[Gesner Passos]

SANS: BeamCentre support for high angle detectors bank

re #5942

• SANSRunWindow.ui: Add widgets inside Geometry Tab that allows to show/edit the centre for the high/low angle bank.
• SANSRunWindow.cpp: Interact with the changes in SANSRunWindow and also with the changes in the script in order to support both detectors.
• isis_reducer.py: The changes made here is to support the definition of the centre for both detectors, allowing to get its position get_beam_center and to define their positions. It does extend the class Sample to allow reloading the data to move the detector bank component to the correct position in order to apply the reduction.
• isis_reduction_steps: Extend parsing the USER FILE, in order to accept the commands: SET CENTRE/[MAIN/HAB].
• ISISCommandInterface.py: Adapt the FindBeamCentre method to support both detectors, adapt the WavRangeReduction to reload the dataset for moving the hab detector to its center in order to correct use this parameter for the reduction. Extends the method SetCentre. Changeset: bab290eb5b68fad8f6ef9209d9987a8e961d4da6

[Gesner Passos]

User reported a bug related to this ticket

[Gesner Passos]

The error was due to incorrect assumption: the detector bank was positioned at its defined beam_center. While it used to be true, after this ticket, the user is allowed to change the beam_center variable, without moving the detector, which causes the detector not to be centered at its 'beam_center' anymore. As long the movement are always relative, the calculation was always at the same positions (but the beam_center was reported as different).

It is necessary to change the FindBeamCentre to consider the current position of the bank when it starts.

[Gesner Passos]

BugSolved FindBeamCenter wrong answer

SANSRunWindow.cpp : add the centre information from the Geometry tab, so to make it to be considered in SingleMode. ISISCommandInterface.py: original does not take the beam_center position, but get the position of the center of the bank detector. Avoiding the wrong assumption that the detector bank will always be centered at its defined beam_center. isis_instrument.py : add a method cur_detector_position that returns the position of the center of the detector bank, that is used in ISISCommandInterface

re #5942

Changeset: b93e836e631a2156e3fc376672cea6f2c822a64e

[Gesner Passos]

BugSolved FindBeamCenter wrong answer

SANSRunWindow.cpp : add the centre information from the Geometry tab, so to make it to be considered in SingleMode. ISISCommandInterface.py: original does not take the beam_center position, but get the position of the center of the bank detector. Avoiding the wrong assumption that the detector bank will always be centered at its defined beam_center. isis_instrument.py : add a method cur_detector_position that returns the position of the center of the detector bank, that is used in ISISCommandInterface

re #5942

Changeset: b1e4536de3ae3dfe55387b8d2b620ea4e16d8c8b

[Gesner Passos]

BugSolved FindBeamCenter wrong answer

SANSRunWindow.cpp : add the centre information from the Geometry tab, so to make it to be considered in SingleMode. ISISCommandInterface.py: original does not take the beam_center position, but get the position of the center of the bank detector. Avoiding the wrong assumption that the detector bank will always be centered at its defined beam_center. isis_instrument.py : add a method cur_detector_position that returns the position of the center of the detector bank, that is used in ISISCommandInterface

re #5942

Changeset: b93e836e631a2156e3fc376672cea6f2c822a64e

[Nick Draper]

Moved at the code freeze for release 2.4

[Alex Buts]

Have to go to the meeting so have to return it to the pool as there are a lot of unclear behaviour needed investigation.

[Martyn Gigg]

Checked running the beam centre finder for both main & HAB and the results looked sensible. The widgets reflect the values from the MASK files as expected when loaded.

[Gesner Passos]

SANS: Fix Find Centre for SANS2D

The implementation of #5942 broke the same feature for SANS2D. The problem was a different definition of the coordinates. This patch solves it.

re #5942

Changeset: f4a56f4dc39750b471e22f8c6022ea696133790c

[Gesner Passos]

Tester:

• Open: SANS Interface
• Select SANS2D instrument
• Load Mask ​MASKSANS2D_123T_4m_Xpress_8mm.txt
• Set Sample 16187 (cycle_12_3)
• Click on Load - it will create the Workspace::16187_sans_nxs
• Show instrument on this workspace
• Change to Geometry Tab
• Right-Botton Corner: apply the Run Push Button.
• Check that while the iterations goes on and on, the detector move towards the center of the scattering.

[Martyn Gigg]

Looks good. The detector seems to move as expected to the centre of scattering.

[Stuart Campbell]

This ticket has been transferred to github issue ​6788