[Jenne, Corey, RyanS, Jane Glanzer]
After EE fininished cabling ISCT1 and IOT1, Keita and I put up laser barriers to make the South Bay of the LVEA local laser hazard ("bifurcated"), so that both tables can be opened at will.
Please pay attention to the signs on the laser barriers, and if the barriers are closed and / or the signs show Hazard, then wear laser safety goggles beyond the barriers.
The Vac team opened the gate valves, and we ran the baffle align scripts. After the baffle align scripts completed, I did not touch ITMX again.
Corey and I moved PR3 so that we could see beams on the cameras (we later reverted PR3's sliders), and moved ETMX and TMSX until we had nice TEM00 flashes. We were then able to lock it and run then offload the ETM_TMS_WFS.
With Xarm nicely aligned and PR3's sliders reverted, we had great transmission on ALSX and a familiar looking spot on the camera. However we didn't see anything on the Yarm PD or camera. So, I moved the BS until I could see something (also having increased the exposure of the camera so we could see the straight leakage beam), and then moved ETMY until we started to get flashes. I aligned ETMY and TMSY until we could hold lock on TEM00, and moved the BS until we had ~max transmission on ALSY's transmission PD. We then ran then offload the yarm's ETM_TMS_WFS.
I then (since HAM1 is at much lower pressure than 10 mTorr) opened up the ALS light pipe, and went to check that the alignment on the table looked "reasonable". Indeed, it looks reasonable, in that the PSL beam seems to go nicely through the SHG and is roughly centered on downstream optics. However, we don't have good beatnotes. I had a quick look at the beams headed toward the beatnote PDs, and at least one is easy to see that there are 2 distinct beams headed toward the PD. I don't recall on the top of my head if this is the Diff beatnote though; if it is, then it depends on the BS alignment, so we likely want to hold off on doing any on-table alignment until we have a better idea of the BS alignment relative to the ITMs.
At Sheila's suggestion, I also reset the green initial alignment references (SDF table attached just before accepting them), so that we have an easier time coming back to where we are now. As usual, we'll have to re-reset them after we achieve full 2W lock.
In summary: ITMs were set with the BafflePD script. Green ETM_TMS WFS were run and offloaded. Nothing on IST1 was touched (yet), but it's clear that we'll likely need to do some on-table alignment.
Proposed next steps: Check BS alignment by looking at MICH (so, after JAC is locked, then IMC locked, then XarmIR aligned). Then, consider aligning the ISTC1 beatnotes. Then, lock the whole IFO!
(jenne, ryanS, corey)
NOTES on Green Arm Alignment Recovery After Gate Valves Opened on Mar 5, 2026 for Jenne & Corey (Using Sheila/TJ notes as a reference and adding notes for what was done 3/5/26).
After closing gate valves, alignments tend to shift making recovery harder. In the corner station, the ITM camera pointing will shift enough to make the camera offsets unusable. Sheila posted instructions on how we should recover this in alog88346, detailed below.
= Instructions =
- Do Initial Alignment WITHOUT using green cameras in the loop, as the cameras are right next to the gate valves and have now been jostled around and have lost their previous reference history. (The camera references are very touchy to any movements/bumps anywhere near them!)
- Open INIT_ALIGN.adl (On Sitemap/ASC/Init Align)
- On the Scopes drop-down, open the X & Y Arm Baffle PDs scopes
- With SUS Guardians, MISALIGN the ITMs & ETMs
- On the Dither Align Scripts X & Y Arm Drop Downs, select TMSx & TMSy (they can both run at the same time & you can monitor their progress via their ternimals). These scripts are done when the terminal notes a successful completion. TMS scripts completed successfully (but did not see spots on the ASLx & ALSy cameras).
- Moved on to ITMs (took ITMx/y to ALIGNED state). Opened the (x & y) arm Baffle PD scopes, and then ran the Dither Align Scripts for ITMx & ITMy. (Once these scripts are successful, we will then try not to touch the ITMs any more.)
- ITMx finished successfully
- ITMy did not. Jenne trended the BS & ITMy and took them to previously good alignment (~85 days ago)--mostly yaw for both. Still did not see spots on the ALS x & y cameras!
- Started to look at PR3, but Jenne noted we generally do not want to touch the pointing on PR3.
- Went out to ISCT1. AND discovered that the Shutter ("ISCT1 ALS cavity beams") was CLOSED! NO Changes made on ISCT1! Returned to the Control Room since we now had a beam to work with!
- Temporarily touched PR3 to center spot on the ALSx camera (reverted later).
- Touched TMSx, ETMx (NOT ITMx) to get something on the camera. Spot looked like a "coffee bean" spot....started to revert PR3...AND, the spot looked much better.
- Went to LOCK ALSx and it immediately locked up on a 00!
- Selected LOCKED_SLOW_WFS_ETM_TMS state for ALS_XARM (this does not use cameras), but WFS weren't happy....but (ryanS noticed) this was because the guardians were stalled. Needed to push AUTO & this cleared the STALL on Guardian.
- Touched ETMx & TMSx (mostly in yaw) & then went for LOCKED_SLOW_WFS_ETM_TMS again, and this time WFS took Xarm to ~1.
- After PR3 was restored (its yaw), went to ETM_TMS_WFS_OFFLOADED and ALSx was good.
- On To The ALSy
- Didn't have ASAIR video to look at due to no beam getting through JAC
- Trended BS sliders, osems, oplev and found good values ~85 days ago right after a Manual Initial Alignment
- Tweaked BS while looking at camera (and a previous good spot)---did not see anything on the camera
- Increased ALSy camera exposure & eventually saw a spot (actually two [thought it could be ALSx---so unlocked X-arm & closed the "ISCTEX green beam" shutter). But still saw both spots--so the two spots were Y-Arm!
- Move ETMy to get the two spots on top of each other and then Jenne eventually got a great spot.
- Around this point, a polarization error was noticed on guardian; RyanS mentioned the CHANGE POL guardian state can take care of this. So this was selected for ALS x&y.
- Returned to touching up y-arm w/ ETMy, TMSy
- Jenne mentioned, "Y-arm is finicky, and" you need its flashes close to 1. (we were around 0.6)
- Took a break & switched to BS moves in yaw and then returned to "cavity alignment" (ETMy/TMSy)
- Spent a bit of time aligning the cavity, but could only get to about 0.8
- Made some gain changes on the Y Arm PDH medm, and then more cavity tweaking for a few minutes.
- Eventually got there after careful tweaks and returning to the BS
- Checked the beatnote.
At this point, we were good with green arm alignment!