How center the beam and check its position with the YAG scintillator

• Put the YAG screen in place on the PHI axis with the flat side perpendicular to the beam. 
• Put the light in and verify that the fluorescence (green) area is in the beam, if not center it properly. Go to zoom 3 or 4 and focus the image until you can see the YAG details as in the figure below.
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• Put the light out and open the Safety Shutter and the Fast Shutter. A green spot (=the beam) should appear. On the most intense beamlines (i.e. ID23-1, ID29) decrease the trasmission to less than 5% to avoid excessive fluorescence. Click on the Center Beam button to center the beam on the red cross and the beam will be automatically re-centred.
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• Take out the YAG screen and carry on with your experiment.

How to check the beam position with the pop-up scintillator (ID23-2 feature)

1.  Click on "intrumentation" in mxCuBE
2. Select "Scintillator"; open the "Safety shutter" and the "Fast shutter". A green spot should appear. If not, check if the search has been done in the hutch. The green spot (= the beam) should match the red cross; if not, move down the collimator (mvr bstopz -5 in spec(exp)),  click on the "CentreBeam" button (next to the "Beam realign" button) and follow the instructions.
3. Unselect "Scintillator" from the "intrumentation" menu in mxCuBE.