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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 room alignment procedure has already been completed.

A) Beam transport alignment: HeNe

As of April 2022, we use the HeNe auto alignment for B0-B3. B4-B6 are aligned manually because they are noisy.

1. Open S20 Laser Transport Multi Profile Monitor (FACETHOME→Matlab GUIs→S20 Laser Tools→S20 Laser Transport Multi Profile Monitor).
2. Start display and check profiles look fine (cameras are running). Unblock HeNe (button on auto align GUI) if blocked.
3. Make sure ROIs are set somewhat tightly, set Zoom ROI in Profile Monitor GUI if needed.
   
4. Press 'Stop Alignment' (red button) on auto align GUI.
5. Set camera exposure time for beam transport cameras by pressing 'HeNe cameras' (see Figure 1).
6. Tick boxes for 'HeNe Near and Far', 'B0 and B1', 'B2 and B3'.
7. Click 'Clear References', then 'Grab References'. This might take a few seconds.
8. Click 'Start Alignment'.
9. 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:

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 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 RP attenuator if not already inserted. Then remove the foam.
5. Set energy attenuator to maximum energy, rotation 119deg (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. Turn LSS-2 key to ON to allow IR beam to go through transport.
2. Open EPS shutter (FACETHOME→Laser→LI20, red means the EPS shutter is open).
3. On the auto align GUI, press the button 'IR mode'. This will stop the current alignment and opens a new window (see Figure 3).
4. 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.
5. Click 'Clear IR references', then 'Grab IR References'.
6. Click 'Start IR alignment'.
7. Monitor the log to make sure that the offset tolerances were set appropriately and that the auto aligner does its job.
8. Once converged, press 'Abort IR alignment'.
9. 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.
10. On main window of auto align GUI, click 'Clear References', then 'Grab References'.
11. Then click 'Start alignment' to resume HeNe and laser room auto alignment.
12. Monitor the log to make sure that the offset tolerances were set appropriately and that the auto aligner does its job.

G) 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.