Aligning the beamstop

How to realign the beamstop

The beamstop is automatically moved up by 25 mm when you enter the experimental hutch and should be automatically placed back in position when the experimental hutch is interlocked.

If you enter the experimental hutch and the beamstop does not lift up away from the sample position check that the Automatic Beamstop Removal box has been clicked in the the Beamstop Operations brick of MxCube. If it isnt then restart it by clicking on this box and wait for the beamstop to go up.

Note: Occassionally this goes a bit screwy and you need to click on the box to select then deselect this option a couple of times before the beamstop goes up. This usually happens when MxCube or PX has hung..

It is good practise to also make a quick visual check that the beamstop is in the correct position before taking an image, either by looking at the cameras around the sample position (on the TV screen in the control hutch) or by checking the position of the motors bstopZ and bstopY in the MxCube Beamstop Operations brick. Normally both these motors should be at 0.

How to realign the beamstop

If you can see a dark (or red) mark or stripe in the center of the detector then beamstop has been knocked and needs to be realigned. You can do this from MxCube by clicking on the Beamstop Alignment button in the Alignment operations brick.

Occassionally, you might need to make small relative movements of bstopY (horizontal) and or bstopZ (vertical)

You can do this using by inputting small (eg +/- 0.1mm) relative movements in the bstopY and bstopZ position boxes in the beamstop operations brick.

If you need to move the beamstop closer or further away from the sample ie if the beamstop shadow is too large. You can also change the position of bstopX in this brick. The current range is between (0)16 mm (closest) and 20 (35 mm furthest beamstop position).