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Procedure to align the transport using the HeNe and align the IR beam to the HeNe.

Assumption is that the Laser Startup Procedure procedure has already been completed and thus an auto-aligner GUI is already open and running on the laser room cameras.

A) Beam transport alignment: HeNe

  1. Press Stop Alignment (red button) in the auto-aligner. This will stop any scripts running on other machines.
  2. Set camera exposure time for transport cameras by pressing HeNe cameras (see Figure 1).
  3. Open S20 Laser Transport Multi Profile Monitor (FACETHOME→Matlab GUIs→S20 Laser Tools→S20 Laser Transport Multi Profile Monitor).
  4. Start display and check profiles look fine (see reference image below), cameras are running, and laser is visible.
  5. Verify ROIs are set somewhat tightly (see above image), if the full camera ROI is visible see Procedures to Fix Common Issues.
  6. If the laser is not visible on B4, B5, or B6
    1. Tick boxes in the auto-aligner for HeNe Near and Far, B0 and B1, and B2 and B3.
    2. Click Clear References then Grab References. This might take a few seconds. A message will be printed in the log saying grabbing is completed.
    3. Click Start Alignment. The software will loop through the list of cameras (top to bottom), calculate offsets and then move motors.
    4. Once the laser looks good is visible on S20PreampOutB4, S20MPANearB5, and S20MPAFarB6, click Stop Alignment (red button).
    Insert image of the multi-profile monitor with badly aligned beam
  7. Tick boxes for first three sets of laser the transport cameras: Pulse Picker and Regen Out HeNe Near and Far, Preamp Near B0 and FarB1, and MPA Near and Far B2 and B3, B4, B5, and, B6.
    1. At this point, all the boxes in the auto-aligner should be checked.
  8. Click Clear References, then Grab References. This might take a few seconds. A message will be printed in the log saying grabbing is completed.
  9. Click Start Alignment. The software will loop through the list of cameras (top to bottom), calculate offsets and then move motors.
  11. Note: For MPA Near and Far the offset is calculated using a 20-shot average. This step takes a bit longer than for the other motors. 
    12. Monitor the log to make sure that the offset tolerances were set appropriately and that the auto aligner does its job.
    1. The auto-aligner will write a warning to the log with a reason when it skips an alignment step.
    2. To fix auto-aligner errors, see Procedures to Fix Common Issues.
  1. Press 'Stop Alignment' (red button) on auto align GUI.
  2. Set camera exposure time for beam transport cameras by pressing 'HeNe cameras' (see Figure 1).
  3. Tick boxes for 'HeNe Near and Far', 'B0 and B1', 'B2 and B3'.
  4. Click 'Clear References', then 'Grab References'. This might take a few seconds.
  5. Click 'Start Alignment'.
  6. Monitor the log to make sure that the offset tolerances were set appropriately and that the auto aligner does its job.
    1. Note: The auto-aligner won't do anything if it measures an offset larger than the tolerance. It will print a warning in the log.
    2. If the offset is very large, >20px, then press stop alignment and manually align according to Beam transport (manual).
    3. Otherwise, click the 'Expert...' button in the auto-aligner. This opens a new window.
    4. Adjust the global tolerance to 20px, reduce back to 5 once the auto-aligner is close.
For manual alignment of B4 (and B5/B6 for main beam), follow these steps:

B) Beam transport alignment: IR

  1. Set exposure times for B4-B6 (FACETHOME→Profile Monitor→LI20→PyDM All Cameras or specific window).
    1. B4 ~ 4 s.
    2. B5 and B6 ~ 1-2 s.
  2. Press 'Stop Alignment' (red button) on auto align GUI.
  3. Press 'Block' under HeNe status to block HeNe.
  4. Open Profile Monitor (FACETHOME→Matlab GUIs→Profile Monitor...).
  5. Open B4, tick box 'Use background', press button 'take background'.
  6. Open B5, tick box 'Use background', press button 'take background'.
  7. Open B6, tick box 'Use background', press button 'take background'.
  8. Press 'Unblock' under HeNe status to block HeNe.
  9. Check on Profile Monitor window that beam is visible enough for alignment.
    1. If not, set longer exposure time (step 1), then repeat steps 3-9.
  10. Use mirrors to adjust pointing to reference positions from Laser cameras and alignment references. 
    1. Picomotors for B4: FACETHOME→Laser→LI20→Infrastructure→MOC-LI20-MC08→Pico 1 Compressor.
    2. Picomotors for B5/B6: FACETHOME→Laser→LI20→Infrastructure→MOC-LI20-MC08→Pico 3 Trans B5,B6.
    3. Use 'Show stats' on profile monitor for B5/6. Might have to zoom in and go by eye for B4 if noisy.
  11. Once done, press 'Clear References' and 'Grab References' on auto align GUI.
  12. Press 'Start Alignment'.
  13. Monitor the log to make sure that the offset tolerances were set appropriately and that the auto aligner does its job.

B) Prepare for IR

Make sure everything in the laser room/tunnel is ready to receive IR laser.

  1. Drive in the compressor beam block, 290 mm 50 is in (FACETHOME→Experiment→LI20→MOC-LI20-MC03 Channel 3).
  2. Ensure IPOTR foils are out (IPOTR1, IPOTR2 and IPOTR1P, found at FACETHOME→Profile Monitor→LI20→IP1 Table).
  3. Block the laser with a foam after the MPA.
  4. Insert the If the RP attenuator if not already inserted. Then remove the foam.Set energy attenuator to maximum energy, rotation 119deg is not in, set the energy waveplate to 80deg (FACETHOME→Laser→LI20→Infrastructure→XPS moc-la20-ls24 Channel 1).

      C) Beam transport alignment: IR

      Once the beam transport is aligned with the HeNe, proceed to overlap the IR with the HeNe. This assumes the IR is aligned to DMNear and Far (see D
        1. If the RP attenuator is in, the waveplate should be at maximum energy.
      2. Ensure the EPS shutter is in (FACETHOME→Laser→LI20 Low and High buttons, green means the EPS shutter is in).
      3. Turn LSS-2 key to ON to allow IR beam to go through transport.Open EPS shutter (FACETHOME→Laser→LI20, red means the EPS shutter is open).
      4. On the auto align GUI, press the button 'IR mode'. This will stop the current alignment and opens a new window (see Figure 32).
      5. Use the buttons in the first line to switch from HeNe to IR:
        1. 'Block HeNe' – drives HeNe block to 10 mm (blocked) from 8 mm (open).
        2. 'Close Iris' – sets iris to -5 mm from -40 mm (full beam size).
        3. 'Set HWP' – rotates wave plate 2 to 65 from 50 (s-pol).
        4. 'Set B0 B1 exposure' – sets exposure on B0 and B1 to 1 s (from 1 ms).
        5. 'Unblock EPS Shutter' – opens EPS shutter.
      6. Check that the IR beam profiles look fine on B0 and B1 (see reference image below).Image Added
      7. Click Click 'Clear IR references', then 'Grab IR References'.
      8. Click 'Start IR alignment'.
      9. Monitor the log to make sure that the offset tolerances were set appropriately and that the auto aligner does its job.
      10. Once converged, press 'Abort IR alignment'.
      11. Then follow the steps in line 4 to return settings to HeNe alignment mode:
        1. 'Block EPS Shutter' – closes EPS shutter.
        2. 'Open iris' – opens iris from -5 mm to -40 mm (full beam size).
        3. 'Set HWP' – rotates wave plate 2 from 65 to 50 (s-pol).
        4. 'Set B0 B1 exposure' – sets exposure on B0 and B1 to 1 ms (from 1 s).
        5. 'Unblock HeNe' – drives HeNe block from 10 mm (blocked) to 8 mm (open).
        6. Close the IR alignment window.
      12. On main window of auto align GUI, click 'Clear References', then 'Grab References'.
      13. Then click 'Start alignment' to resume HeNe and laser room auto alignment.
      14. Monitor the log to make sure that the offset tolerances were set appropriately and that the auto aligner does its job.

      D) Beam transport alignment: Drifts and fixing alignment

      As long as B4 and onwards are not automatically aligned and kept aligned, slow drifts are expected over time. B4 is the first mirror in the tunnel and sees the pointing from B3 through the penetration, which is probably the longest distance between two mirrors in the beam transport. B3 pointing (seen on B4) is affecting both the main beam and the probe. The probe line is particularly complex and suffers greatly from these drifts.

      The simplest way to fix up alignment is by manually re-aligning B4 (and B5/B6 for main beam alignment). See E), second part, for instructions
      1. .

    Figure 1: Auto alignment GUI


    Figure 2: IR mode GUI