GDA is organised into perspectives, which allow the user to switch between different modes of operation, e.g. diffraction and tomography. Each perspective is logically arranged into different tabs, which split up the functionality. For example, the imaging perspective is divided into three tabs. GDA provides a user interface to the beamline for data acquisition.
Start GDA by typing the following in a user workstation:
gda client
The following window will initiate momentarily.
DASHBOARD: SETUP PANEL
Purpose: Set up and optimise collection and sample centering.
Experiment name – This is an ID under which all scans will be grouped. Experiment must be started to collect data.
Acquisition Type – Diffraction or Imaging
Beam Selector – Diffraction or Imaging
EH Shutter – Open/Closed
GTS Positions.
Left box is set value in mm, right box is step value in mm (can be changed). Motion is stepped using up/down arrows.
Cameras
Exposure time is optimised here. Camera streams are turned on using green button. Bright green is on. Red means fault.
Imaging Camera – 0.001 to 1.9 sec
Diffraction Camera – 1-60 seconds.
IMPORTANT – if changing diffraction camera exposure time – turn off monitor before making the change.
CAMERA STREAMS
Purpose: to display a live camera stream (diffraction or imaging)
Imaging:
Default stream tab is a jpeg stream – do not use this for centering/optimising exposure.
Click cameras button in Setup panel and this will open a new ‘Camera Configuration’ Tab.
Note: when pressing Cameras button – new stream tab can open elsewhereSet detector to imaging or diffraction camera and stream to Epics PV Access.
If shutter is open and camera is on this should produce live stream of sample.
A histogram is available to aid understanding.
THE JOB QUEUE
Purpose: reports status of job queue including past and ongoing scans. Returns error messages if scan fails.
Scans are submitted using the Run button in the Configuration panel above the queue.
Stop job - The stop button can be used or you can right click any running or submitted job and select stop or pause job.
Rerunning Jobs - if you right click any job you can select re-run job at which point you specify how many times it will be submitted.
Errors - The Message column will return whether a scan completed or failed. It will give an error message that is used to diagnose the reason for failing. Common Errors: