Vicky, Wen, Naoki, Lisa, Matt, Daniel, Keita, Nutsinee, Camilla, Dhruva
After finding the single pass 532 beam on transmission from the filter cavity, we moved SQZT8 into place in order to help us align FC2. On the green path on the table, we put in a 95/5 BS as a retro-reflector. Once we had the retro set up, we could find multiple beams on transmission. After mostly aligning FC2 in order to collapse these beams into one spot, we started seeing extra beams which were sensitive to the FC1 aliignment. We moved FC1 just enough to try and collapse these new beams and started seeing cavity flashes. We hadn't set up any PDs or cameras to try and quantify this but put a camera in transmission which we plan to access in the future. We went back to SQZT7 and aligned the FC Refl back to the refl PDs and started seeing 5% refl dips. We managed to increase this to around 20% by moving FC2 around. By this point, we started seeing error signals pop up on the FC RF40 demods. So we did what anyone would do and turned on the CMBs. We turned up the gain to around 20dB and put on compensation and managed to get a very rudimentary lock (screenshot attached).
Lots of optimization to do but everyone did a very good job, We went from closed gate valves to a sort-of locked 300m cavity in less than 5 hours!
Next up, frequency dependent squeezing!!!!!!
Documentation of this historic moment.
Congratulations all!
In total, following ZMs moved:
- ZM3 P/Y = -290 / -105 ---> ZM3 P/Y = -110 / -135
- FC1 P/Y = 0,0 ---> P/Y = 231 / -4
- FC2 P/Y = 0,0 ---> P/Y = 310 / 116
FC trans camera output
Yeah I guess those closed gate valves must have been the main problem, after all. Who knew?
Way to go everybody.
exciting times :-)
We connected SQZT8 to HAM8 using aluminum bellows (WP10826). Lexan plate and yellow cover were put on the work table by HAM8.
SQZT8 doors were locked. All viewports on -Y door are covered with yellow caps. HAM8 areas is laser safe.
Here's a couple more photos.
Locked FC at both sites: Congratulations to all. Still can't get my head round that both teams achieved this on the same date, let alone within an hour or so of each other. Just shows the quality of our team across all 4 LIGO locations and beyond. Friday Nov 18th 2022 is for sure a day for the LIGO records.
Calum
Tagging EPO -- congratulations team!