[Jenne, DanB, Cao, Craig, Georgia, Stefan, Sheila]

Some notes on our first initial alignment after the vent.  Despite our meeting this afternoon encouraging use of the automation system, I did much of it by hand since things were so far off. 

• Used dither align scripts to get the rough pointing of TMS, ITM, and ETM for each arm, to get green locked.
  • This was postponed on the Xarm due to the DAC situation - see Dave's alog 52664 with details on the replacement.
  • The Yarm green alignment worked easily. 
  • The Xarm green not so much - we ended up having to leave the DOF3 camera loops off, and just letting the DOF1 and DOF2 true WFS converge, and I moved ITMX to get the green buildup in the cavity good.  But, this left the ITMX green camera with a value quite different from its setpoint.  We did check, and the digital value of the setpoint is correct (i.e. the same value as it was before the vent).  So, I'm not sure if we've just aligned the Xarm to a not so great place, but if we can get locked then the ADS system will tell us the real answer. 
• Xarm IR wasn't getting good flashes.  I moved PR2 and IM4 until we got good flashes, at which point the cavity locked with a transmission of about 0.5.  I moved the PR2 and IM4 a little bit more, and then let the ASC take it from there.
• IMC wasn't coming back at a good alignment, so we paused and hand-offloaded MC1, MC2 and MC3 to the sliders.
• PRX - fine and easy.
• MICH bright align - fine and easy.
• SRY - found that an offset was left in SRCL2, so the prep_SRY state was railing the SRM (prep states should not actuate).

Locking notes:

• Comm and Diff beatnotes pretty low (-15dBm for comm, and -23dBm for diff), but they're good enough that ALS locked right up.  If this really is the right Xarm alignment (which we'll see when we have ADS), then we might have to check PR3's alignment relative to its oplev, or perhaps align the beams on the table.
• Find IR worked well for COMM.  Dan is finding Diff/Yarm.
  • Yarm IR offset was too low, so even though we were getting good resonances, the guardian wasn't recognizing them. This is probably why it passed over several resonances when it tried on its own.
• Had several locklosses from findIR/lockingALS, so moved PR3 a few clicks each in positive pitch and positive yaw to go back toward the position its oplev says it was before the vent.  Comm beatnote now about -1dBm, but diff still about -20dBm.
  • At the next FindIR, I moved PR2 and IM4 a bit to improve the Xarm transmission.  Really, the right thing to have done would be to redo initial alignment after having moved PR3, but we were hopefull that we could just convince the IFO to lock for us....
• The green arm transmissions seem to be moving a bit more in power than I'm used to.  Perhaps because we don't have sensor correction on at the end stations?
  • Dan notes that Xarm green dofs 1 and 2 in pitch definitely see this wobble when the transmission wobbles.
• DRMI flashes looked terrible (we really ought to have gone back to initial alignment...), but we flipped over to CheckMichFringes, aligned BS (pretty significantly in yaw), then got PRMI to lock within a few tens of seconds after touching PRM alignment (again in yaw).
• However, DRMI still wouldn't lock, even with a few minutes of touching SRM. So, we're doing initial alignment, starting from XarmIR.

Initial alignment round 2:

• XarmIR - transmission was about 0.85 (as a result of my moving PR3, and then PR2 and IM4), but ASC brought it back up to 1 without any trouble.
• PRX - fine.
• MICH bright - also fine.
• SRY - fine.  Dan notes that we have a bit of a second beam on the AS camera. Suspciously, it's in yaw, which is the same dof that we were having problems with on the Xarm green earlier.

Locking:

• Diff again failed to find IR. 
• PRMI caught quickly, although still has a ~0.2 Hz wobble.  Dan says that they've seen this in the past week or so, and never got DRMI to lock and hold.  The solution previously was improving some alignments.
• DRMI caught for 0.85 seconds (not very long, but best we've seen...) and had a 200 Hz oscillation.   
• We're going to go back and try to get the Xarm alignment better.

Alignment, round 3:

• Starting over with green arms.  Yarm looks good still, but Xarm's yaw camera error signal is very large, about -1.  As this goes toward zero, the Xarm transmission starts to decrease until we lose lock.
• Letting Xarm dofs 1 and 2 (WFS) go, but we have the input to DOF3 turned off again.  Going to see if we can walk ITM to get this closer to zero.
  • Dan is moving ITMX quite a lot in yaw, but we're getting the camera signal closer to zero.  I'm moving PR3 in yaw to keep the ALS beams on ISCT1. 
  • We're also moving the BS a bit to get the AS fringes looking more reasonable, although with this large of a move in ITMX, we're back to wondering if we can trust the camera.
  • Dan succeeds!  All of the Xarm green loops are closed, and the green transmission is about 0.9. 
    • But, we can't get the Xarm green transmission back with any kind of PR3 moves, the diff beatnote is down to -40dBm and we can't improve it with any combo of PR3 and BS, and the ALS cameras on ISCT1 look pretty clipped.  This doesn't really feel like a great alignment, unless there was a big change on ISCT1's ALS side, which there kind of can't have been, since it'd have had to be at the periscope where the X and Y beams are still together, and that's so far away from everything that it's basically inconceivable that the periscope mirrors could have been bumped.  So, back to questioning the Xarm initial alignment setpoints...
    • The digital values for all of the Xarm initial alignment setpoints are the same as they were before the vent, so it's not a digital setpoint issue.
    • A next step (that we won't be taking, at least tonight) if we trust the ITMX green camera would be to realign beams on ISCT1.  We're going to avoid doing that, since that's not nearly as un-do-able as digital sliders.

Plan going forward:

• Maybe go back to the Xarm alignment we had after alignment round 1, and continue trying to lock, so we can check the spots with ADS? 
• Check suspension top mass witnesses and optical levers, and see if the alignment round 1 locations are at all similar to pre-vent values.
• Brainstorm with others for more ideas.