Results tagged “switch” from The SIBYLS Beamline

Beamline Diagram

Focus Beam at Beamstop with Experimental Table Between PX and SAXS

Check Helium tank outside of hutch to make sure it is full and that it is flowing into the shutter box. It is important to purge all air from the shutterbox as the ion-guage needs to report a consistent value.

Turn Helium on as early as possible to assure shutterbox is purged

In a terminal window turn off the feedback with the following command: off

Switch KVM to the Beamline computer, and launch "Shortcut to BL Control Main".

Click the white arrow in upper left of main window. This will open the "Beamline 12.3.1 Beamline Control System" window.

Open bothe the Motor Debugger and Motor Monitor modules from the "Motors" pulldown menu.

Turn on autoscaling under the "Amplifiers" pulldown main menu. (why?)

Set M2 Bend Up to 244000, and click move button.

Set M2 Bend Down to 267000, and click move button.

Change "Mono eV" to 10000.

Remove the safety pin and use the hand crank to move the table to the mid point. There is a piece of red tape marked in pen "YAG" indicating the proper midpoint position of the table.

Attach the BNC cable to the camera that monitors the YAG prism, and focus the camera (this step will hopefully be unnecessary once a more permanent camera position is established.

Close the hutch.

Open the main shutter. You should see the direct beam hitting the YAG prism at this point.

Select "tune rocking curve" and click either the step ⬆ or the step ⬇ button once to initialize the optimization procedure. (this automagically adjusts Theta2)

Select "M2 Tilt" and click the home button to reset all values to 0.000

Move M2 Tilt to 12000.

Some PX users will have adjusted the Slits1 to make a very tight beam so they should checked and backed off if necessary. Aperture Line 1 and Aperture Line 11 values should be decreased several unit values.

If you lose the beam jog M2 Tilt in 100 unit increments (this should move the beam up and down on the video monitor).

Select "Chi2" (value should be ~0.492) jog Chi2 in 0.01 increments. (this should move the beam left and right on the video monitor). Because Chi2 is adjusting the focus of the beam changes to this value will drastically alter the shape of the beam.

Sometimes the table will need to be moved slightly in order to position the beam in the middle of the YAG. Additionally the shutter control cable may sometimes get in the way so it must be unplugged from the shutterbox. Turn off power on shutter control box and unplug cable.

Close hutch and turn off hutch light.

Open main shutter and make sure video monitor is turned on.

Optimize the shape and size of the beam. You want it as round and small as possible. Make small adjustments to both Chi2 and M2 Tilt.

Move Experimental Table to SAXS Position

Move the table all the way into SAXS mode using the hand crank. There is a digital dial attached to the air table's sub-frame. Crank the table until this value reads zero.

Re-attach the shutter control cable to the shutter box and turn on the power to the shutter control box. Press the small red button on the shutter control box to really turn it back on.

Close hutch and open main shutter.

Optimize Slits 1, Slits 2, and Slits3 - itertatively

Make sure that the video signal going to the beamline computer is displaying the Beam Position Monitor (BPM) video-feed from the camera that points into the shutter box.

Turn on feedback with the following command: on

The point here is to move slits1 (Aperture guys) and slits2 (SAXS aperture guys) and slits3 (Guard Slits guys) back in as far as possible without actually clipping the beam.

The beam on the back of the shutter may be a bit rough on the bottom edge as a result of nicking slits2 and may look like this:

Jog M2 Tilt to move the whole beam slightly up.

Make sure the High Voltage control unit that feeds the ion guage in the shutterbox has not been tripped. If it has been tripped then reset and increase voltage to as close to 300V as possible.

Close all four slits1 blades as far as possible without clipping beam.

  • Aperture Line 1 moves in from the right
  • Aperture Line 11 moves in from the left
  • Aperture Upper moves in from the top... duh
  • Aperture Lower moves in from the bottom... duh

Close all four slits2 blades as far as possible without clipping beam.

  • SAXS Aperture Line 1 moves in from the right
  • SAXS Aperture Line 11 moves in from the left
  • SAXS Aperture Upper moves in from the bottom... huh?
  • SAXS Aperture Lower moves in from the top... huh?

Insert all filters into direct beam and take a 1sec shot on the MAR CCD.

Close all four slits3 blades as far as possible without clipping beam.

  • Guard Slits 1 more + values to close blade down. (Left side)
  • Guard Slits 11 more - values to close blade down. (Right side)
  • Guard Slits Upper more + values to close blade down.
  • Guard Slits Lower more - values to close blade down.

Reduce Reflections from Slits3 and adjust beamstop

Take a 1 sec shot on MAR CCD. It will look something like this:

Back off the Guard Slits Upper and Guard Slits Lower until the vertical streaking is eliminated. (streaking toward the top of the screen is caused by Guard Slits Lower being too far in, and vice-a versa for streaking downwards)

Back off the Guard Slits 1 and Guard Slits 11 until the horizontal streaking is eliminated. (this is usually less of a problem, but again streaking to the left is caused by x-rays reflecting off of Guard Slits 11, and vice-a-versa for streaking to the right)

Adjust Endstop y to move the beamstop up and down.

Adjust Endstop x to move the beamstop left and right.

Center the beamstop by observing a line integration tool drawn though the beamstop. The idea is to get a symmetrical background scatter aboce and below the beamstop shadow.

Define Beam for Users

Enter hutch. Manually open the experimental shutter. Insert CCD shield. Insert sample cell with fluorescent paper.

Close hutch. Open main shutter and define the bounding box for the beam on the video monitor.

It may be necessary to move the sample up or down (Sample x and Sample y) so that the beam enters the sample cell in the center.

Enter hutch. Close experimental shutter. Remove CCD shield.

You are now ready to CRUSH!!!!!

ALS Ring Status

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