This is a late alog, but I wanted to put it in to document. In July, Randy installed an acrylic barrier on the pipe bridge that would block any spray from a failed cooling line expansion joint from spraying onto squeezer electronics racks or optics tables. Associated FRS30283
TITLE: 10/27 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Earthquake
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
SEI_ENV state: EARTHQUAKE
Wind: 10mph Gusts, 7mph 3min avg
Primary useism: 0.19 μm/s
Secondary useism: 0.26 μm/s
QUICK SUMMARY: H1 lost lock at 12:48 UTC after spedning almost 16 hours locked from a M6.5 EQ out of the Caribbean. Still in EQ mode, so will start relocking once ground motion calms down.
H1 back to NLN at 16:57 UTC.
Ran in initial alignment then set to relocking automatically. Paused in a couple of places on the way up for Elenna to make some ASC measurements, now starting some commissioning activities which are slated to be wrapped up by 18:30 UTC.
And of course as soon as I'm about to post this, lockloss @ 17:14 UTC from what looks like an ETM glitch.
At [?] in the morning H1 was Found Locked but SQZ_Man was upset.
SQZ_Man stuck in loop from Beam Div_Open_FRS ->FC_WAIT _FS.
SHG H1:SQZ-SHG_TEC_SETTEMP was adjusted down to maximixe H1:SQZ-SHG_GR_DC_POWERMON
still stuck in loop
Ran the noconda python switch_nom_sqz_states.py without script
....UH.... Broke all the SQZr Gaurdians.... Ooops
Ran the noconda python switch_nom_sqz_states.py with script
Taking SQZ_man to no_squeezing
Ran the noconda python switch_nom_sqz_states.py without script.... again
Nothing broke !!! But Still cannot get to observing.
Had to manually take SQZ_ SHG to Down.
Back to Observing. Range only at 133 Mpc
The problem was that the OPO pump ISS was running out of range, as the OPO reflected power has slowly been increasing since our last crystal move. I've adjusted the wave plate on SQZT0 to allow more green power to be launched, this now gives a control mon of about 5 when the OPO transmission is 80 uW.
TITLE: 10/26 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 150Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY:
H1's been locked 8+hrs & microseism continues to fall (almost touching 50th percentile line) and winds are calm.
LOG: n/a
Summary
I found vibration coupling associated with motion of the HAM4 ISI (at a few times background), BSC2 ST2 motion (at about 10 times background), and, likely, on the chamber walls of the ITMs (accounting for much of DARM in the 20 Hz region). The coupling associated with HAM4 may be due to reflection of the 45 degree annular beams from the BS and its cage, and may be mitigated by BBS installation and table baffles at HAM4. The coupling at the chamber walls of the ITMs may be due to the 20 degree annular beam from the ITM bevels, which would be mitigated by installation of cage baffles on the ITMs. However, I would like some more commissionsing time to be more sure of this.
Recently, broad-band non-linear vibration coupling in the corner station was revealed by investigations of the coupling of HVAC components to DARM (86412). This is an update on searches for the site of that coupling.
We check for sites on the internal tables (ISIs) by shaking individual ISIs or HPIs. Discriminating between sites on the vacuum enclosure is more difficult because shaking at one location tends to shake many vacuum chambers about the same amount. To identify an enclosure site, we use frequency dependance and propagation delays (velocities on these steel membranes are only 100s of m/s). The basic idea is that if a patch of chamber wall is producing noise by reflecting scattered light back into the interferometer, then an accelerometer that is placed on the outside of that patch will, comapared to other accelerometers, produce a signal that is precisely correlated with the signal in DARM.
Internal tables
I eliminated most of the tables in the LVEA either by injecting into the ISI control loops or by monitoring their motion during external injections. However, I did find coupling at the HAM4 ISI and the BS ISI.
Coupling at HAM4 ISI
Figure 1 shows that we found coupling at the HAM4 ISI. An increase in Y-axis motion of about 30 produced a feature in DARM that was several times background. This coupling appeared mainly linear and so was not the coupling we were looking for. A potential source of this coupling is reflection of the 45 degree annular beam from the beamsplitter that illuminates this table (83050). The BBS, its less reflective cage and planned table baffling may mitigate this coupling.
Coupling with motion of ST2 of the BS ISI
Figure 2 shows that I produced noise in DARM by shaking the BS ISI. I did a series of injections that suggest that noise in DARM is produced by motion of BS ISI ST2 (where the cage is attached), but not motion of ST0 (where the eliptical baffles are attached) or of the BS itself. This noise may be associated with the 45 degree annular beam from the BS (83050) and may be reduced with the new BBS cage, which is less reflective.
Vacuum enclosure
I have been using three techniques to find coupling sites on the inside walls of the vacuum enclosure. These tests, while ongoing, have narrowed down the non-linear coupling to the enclosure walls in the vertex.
1) Shaker and speaker sweeps from multiple locations
Shaker sweeps are used in two ways. First, frequency consistency - if an accelerometer is mounted at the coupling site, and shows a resonance at some frequency, then there should be an indication of greater motion in DARM at that frequency also. Second, consistency for vibration injections from multiple locations. Thus if the accelerometer is mounted at the coupling site, and it moves less for injections onto the mode cleaner tube than onto BSC8, then DARM should also be less affected by the SR tube injection. Figure 3 illustrates this for one of the sweep pairs.
The most consistent accelerometer locations in frequency: ITMX, ITMY and BS chamber walls
The most consistent accelerometer locations in response to different shaker locations: ITMX, ITMY and BS chamber walls
2) Beating shakers technique
The Beating Shaker technique (52184) uses differences in propagation time from different shaker locations to locate the coupling site. When two shakers inject at two slightly different frequencies (e.g. 35.005 Hz and 35 Hz), the beat envelope will have a different phase at different locations due to propagation delays. If the accelerometer is at the coupling site, its beat enveope will be in phase with DARM’s for any shaking location.
The beat envelope in DARM was not as clear as it has been for past uses of the Beating Shaker technique, because of the side bands. So I fit a simulated beat envelope using a cross correlation technique. This is illustrated in Figure 4. The best accelerometers for beat consistency were ITMY–Y, ITMY-X and ITMX-Z. I think it might be useful for DetChar or others to search for an ASC motion that could account for the side bands during the injection period shown in Figure 4.
3) Hand held mini-shaker
A small shaker made of a speaker with an attached reaction mass (Figure 5) is used to take advantage of the large amplitude near-field region right at the shaker in an attempt to find a region on the vacuum enclosure where the shaker coupling dramatically increases. This technique eliminated the BSC7 potential sites and I hope to use it to test the 20 degree ITM beam hypothesis in future commissioning sessions.
Since our accelerometer array has low spatial resolution (something to think about for CE) we also mount temporary accelerometers as we narrow in on a site. This is the stage I am at, mounting accelerometers to further narrow the site. However, the results so far are consistent with coupling of the 20 degree beam from the ITM bevels (83050) . These annular beams were elimited by the cage baffles at LLO and we plan on installing them at LHO.
TITLE: 10/26 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 151Mpc
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 13mph Gusts, 7mph 3min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.30 μm/s
QUICK SUMMARY:
H1's been locked just over 3hrs with range hovering arouind 154Mpc.
In the last 14hrs, microseism has steadily been dropping off the 90th percentile line. Winds are calm-ish for the last 8-ish hours.
TITLE: 10/26 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 153Mpc
INCOMING OPERATOR: Corey
SHIFT SUMMARY: Two lock acquisitions today, both of which had locklosses during TRANSITION_FROM_ETMX on the first try. This made the relocking times a bit longer, but generally the process was automatic. H1 has been locked for 2.5 hours.
Now that we're back to observing with regularity after a week full of intense troubleshooting, I decided it would be nice to have a summary of the events that contributed to IFO locking issues in the past week and what was done along the way to fix them all in one place, so that's what I'll attempt do in this alog. Anyone should be encouraged to add comments with things I missed or additional commentary. Things I believe to be the most significant changes either contributing to or fixing IFO locking issues I've bolded.
Lockloss @ 18:54 UTC after 1:41 locked - link to lockloss tool
No obvious cause, but I did see a couple glitches in the PRG a few seconds before the lockloss.
Back to observing at 20:59 UTC.
Had another lockloss during TRANSITION_FROM_ETMX so relocking took a bit longer than usual. Fully automatic otherwise, except for some touchup of PRM I did during DRMI acquisition.
FAMIS 27400
Laser Status:
NPRO output power is 1.858W
AMP1 output power is 70.71W
AMP2 output power is 140.2W
NPRO watchdog is GREEN
AMP1 watchdog is GREEN
AMP2 watchdog is GREEN
PDWD watchdog is GREEN
PMC:
It has been locked 33 days, 0 hr 29 minutes
Reflected power = 25.05W
Transmitted power = 106.7W
PowerSum = 131.8W
FSS:
It has been locked for 0 days 2 hr and 11 min
TPD[V] = 0.5278V
ISS:
The diffracted power is around 3.4%
Last saturation event was 0 days 3 hours and 41 minutes ago
Possible Issues:
PMC reflected power is high
Sun Oct 26 10:09:38 2025 INFO: Fill completed in 9min 34secs
TITLE: 10/26 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Wind
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
SEI_ENV state: USEISM
Wind: 31mph Gusts, 23mph 3min avg
Primary useism: 0.05 μm/s
Secondary useism: 0.52 μm/s
QUICK SUMMARY: H1 has been down since 07:09 UTC and struggled to lock overnight due to high winds. Gusts are still high this morning, but I'll try to run H1 through an initial alignment and locking to see how far it gets.
H1 back to observing at 17:23 UTC
Ran an initial alignment then had H1 relock on its own. One lockloss during TRANSITION_FROM_ETMX, which I'm blaming on a combination of wind and microseism, but H1 made it to low noise on the second try fully automatically. I soon saw the 1 Hz ASC ringup after reaching NLN, so I tried raising the CSOFT_P gain to 30, but didn't see the ringup stop. Out of an abundance of caution I transitioned to high-gain ASC, which did stop the ringup, so a few minutes later I set the CSOFT_P gain back to 25.
I also had to run the switch_nom_sqz_states script for observing with squeezing to fix the nominal states of the SQZ Guardians since it looks like Tony must have run it at some point overnight.
H1 called me on my owl shift.
When I logged on I was suprised to learned we were only having troubles with the SQZ system in the wind that is howling and gusting to over 40mph.
Since
The SQZ_MAN was trying to get the SQZr back to FDS but kept getting hung up on FC_WAIT_FDS and would drop back down.
I was going to do Observing without squeezing to troubleshoot but we had a lockloss that I'm gonna blame on the wind.
https://ldas-jobs.ligo-wa.caltech.edu/~lockloss/index.cgi?event=1445499787
Running an initial alignment now.
holding in down for the wind to stop breaking the lock.
TITLE: 10/26 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 151Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY:
H1 finally back in buisiness. Had one lockloss during the shift, but relock was mostly automatic. Winds picked up in the last hour & microseism is still high. Owl Shift is on for tonight. H1 range is hovering around 153Mpc.
LOG:
H1 just had a lockloss, this was after observing for 30min with H1 ASC Hi Gn to ride out an EQ.
This relock was mostly automatic (I touched up ETMy/TMSy a tiny amount). After that, H1 automatically went through prmi-check mich fringes & then back to Observing automatically.
TITLE: 10/25 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 148Mpc
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 15mph Gusts, 12mph 3min avg
Primary useism: 0.04 μm/s
Secondary useism: 0.55 μm/s
QUICK SUMMARY:
H1 has been locked at NLN over 2hrs (yay!) after a rough week of no observing since Mon night. Ryan gave me a great summary of the issues/saga that went on all the way up till this morning when RyanS, Sheila, & Elenna fixed H1!
OPS ASSUMPTION: With H1 appearing back to normal, will assume there's an OWL shift for Tony (unless I hear otherwise)
OPS Handoff from RyanS:
We did just get a warning of an EQ and this one M6 in the South Pacific, AND the EQ Response graph has this EQ squarely on the "HIGH ASC" line. Because of this (and high microseism and the locking issues of the week), will proactively take H1 out oObserving to transition the ASC Hi Gn button a few minutes before the R-wave arrives (timer set!)
