aLIGO LHO Logbook

H1 PSL (ISC, Lockloss, OpsInfo)

camilla.compton@LIGO.ORG - posted 11:12, Monday 11 November 2024 - last comment - 15:06, Tuesday 19 November 2024(81193)

Overview of PSL Story so far

After discussions with control room team: Jason, Ryan S, Sheila, Tony, Vicky, Elenna, Camilla

Prior to September 13th:
- No IMC locklosses 80951
- NPRO/FSS glitches present but not bothering us (June 80520, last year 67718).
September 12th: IMC gain redistribution 79998
September 13th: First IMC lockloss
September to October:
- We start noticing FSS glitches and do of tests to understand these.
- They were present in NPRO only with everything else unlocked (part of reason for swapping NPRO)
- Found that these glitches are not new, present in June 80520 and even last year 67718. Maybe they got worse, or maybe we just stopped surviving them as well.
- IMC has periods of being unstable (have to wait in DOWN)
October 9th: IMC gain redistribution reverted 80566
- We have 6 days with only one IMC lockloss
October 15th: NPRO current increased 80687
- IMC lockloses started again
Ocotber 18th: NPRO current reverted 80746
- IMC lockloses continued
October 23rd to 29th: NPRO swapped 80929
- Swapped to new faraday and EOM, both found to be dodgy
Ocotber 30th: Back to NLN
- Had issues with NPRO 81073: found to be NPRO mode hopping
- IMC locklosses continued
October 30th to November 1st: Tests.
- CARM OLG 80956
- IMC OLG 80979
- FSS OLG 80993
- If the PSL ISS is unlocked the IMC can stay locked: 81056
- Attempt to swap TTFSS (reverted) 80983
- Hardboot of PSL chassis h1psl0: 81048
November 6th: PSL mode hopping was fixed by changing NPRO temperature, 81107.
- PSL now stable
- IMC has periods of being unstable
- IMC locklosses continue

Conclusions: The NPRO glitches aren't new. Something changed to make us not be able to survive them as well in lock. The NRPO was swapped so isn't the issue. Looking the timing of these "IMC" locklosses, they are caused by something in the IMC or upstream 81155.

Tagging OpsInfo: Premade templates for looking at locklosses are in /opt/rtcds/userapps/release/sys/h1/templates/locklossplots/PSL_lockloss_search_fast_channels.yaml and will come up with command 'lockloss select' or 'lockloss show 1415370858'.

Comments related to this report

camilla.compton@LIGO.ORG - 15:45, Monday 18 November 2024 (81340)ISC

Link

November 12th:
- Took TFs 81247
- Tightened loose ISS AOM RF cable 81247
- Tested and characterized in-service TTFSS, SN LHO01: tuned notches and replaced a bad PA85 op amp 81247
November 13th:
- IMC stayed locked without IFO 81262
- FSS OLG and gain change 81254
- IMC OLG and gain change 81259.
Novmeber 14th:
- PSL Beckhoff power cycle 81281
- Replace 35MHz with Marconi: 81277
- Tightened loose ISS AOM cable: 81280
Novmeber 18th:
- LSC POP un-clipped 81329
- Issues found with IMC locked checker in ISC_LOCK's READY 81336 (maybe keeping us in DOWN longer than needed)

Updated list of things that have been checked above and attache a plot where I've split the IMC only tagged locklosses (orange) from those tagged IMC and FSS_OSCIALTION (yellow). The non IMC ones (blue) are the normal lock losses and (mostly) only once we saw before September.

Images attached to this comment

camilla.compton@LIGO.ORG - 15:06, Tuesday 19 November 2024 (81365)ISC

Link

Novmeber 14th:
- PMC OLG measured 81283
November 19th:
- Scopes setup at PSL racks 81359
- PMC+FSS only test shows glitches 81356
- Reverted EX 28bit LIGO-DAC change back to 20-bit 81350