Sat Mar 29 10:13:20 2025 INFO: Fill completed in 13min 16secs

TC-B was quite noisy during the fill today.

TITLE: 03/29 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 141Mpc
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 4mph Gusts, 1mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.26 μm/s
QUICK SUMMARY:

• 14:17 UTC observing
• The wind is much lower
• Secondary microseism is decreasing

TITLE: 03/28 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 149Mpc
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY:

Had a bit of moody winds tonight---no sustained winds, not really strong winds, but the middle of the shift had  waves of short gusty periods, two of which took H1 down.  Luckily the winds died down toward the end of the shift, to allow H1 to get back to Observing.  Took ETMy Mode1 to the settings Ryan C mentions in his summary.
LOG:

• 0130 Lockloss (due to EY winds)
  • Ran an Alignment and made it back to Observing for a whopping 4-min, until...
• 0252 Lockloss due to Cornder winds)
  • Ran an Alignment, but while getting ready for PRC, the FSS got fussy.  Toggling the FSS Autolocker was the solution.
  • Ran a 2nd Alignment.
  • 0443 Observing

For FAMIS #26369:  All looks well for the last week for all site HVAC fans (see attached trends).

BRSx is in the middle of both of its thresholds, and BRSy is slowly trending down to the lower threshold.

Not sure what did it to the PSL's FSS, but noticed we were stuck before the PRC portion of Initial Alignment, and DIAG MAIN had the following messages flashing like the devil:

• PSL_FSS:  PZT MON is high, may be oscillating
• PSL_FSS_TPD:  RefCav transmission is low

On the FSS screen, the autolocker was going wild and the PZT_MON screen was all over the place. 

Since the Autolocker was having issues, I toggled the autlocker off/on and this immediately calmed down the FSS and the IMC finally locked back up.

Going to restart the Initial Alignment.  Because the winds are still pretty attrocious. 

H1 was at NLN for 7min only to have another lockloss  at 252utc (1427251941)---as of 434utc this one is still Analyzing, but----Pretty certain this will be chalked up to wind again---this time the gusts were strongest at the Corner (hear alot of wind activity outside and can see lots of tumbleweeds rolling by on the cameras).

H1 had a lockloss from a 4hr53m lock at 1:30utc (1427247021, this has an EY WINDY tag).  Winds at EY were picking up around this time.

Gerardo, Dave:

At 16:51:34 Fri 28mar2025 PDT we had another small vacuum glitch in the LVEA, which this time was reported by VACSTAT, detected by those gauges with increased sensitivity (BSC2, CP2, YARM and XARM). Attached trends show this was a modest ~0.1e-09 Torr increase. Rising edge about 10 seconds, pumpdown time about 3 mins.

H1 was locked throughout. I reset vacstat_ioc.service to clear the alarm.

This week Mitch and I opened the can for the ISI destined for HAM1 and started adding damping parts. Spring, flexure and GS13 can dampers have all been added. TMDs have been mostly assembled, but have not been tuned yet, we will figure that out next week. I just finished setting up the CPS field interface chassis with the new triax sensors after setting the phases for the sensors. For the moment one of the cards is set as a timing master, I will have to change that when we go to connect to the system. Next week, TMD tuning, st0 L4C install, in-vac parts for the new CPS and pre-installing lifting pads and covers for install into the chamber. Then we can close up and wait for HAM1 chamber to be ready to receive.

First 2 pics are a couple shots of the ISI, third shows the TMDs we built this afternoon, which still need magnets and tuning. 

TITLE: 03/28 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 151Mpc
INCOMING OPERATOR: Corey
SHIFT SUMMARY: We lost lock from another earthquake, the wind started picking up during the afternoon but we relocked easily after an alignment. The violins have been damping nicely. The new settings I found for ETMY mode1 are FM1+FM5+FM10 G= -0.1, they damp mode1 well but don't really affect mode6.
LOG:

• 15:19 UTC Observing
  • I set ETMY mode1's gain to zero in lscparams (SUS)
• 17:42 UTC lockloss from a 6.6 from Cape Verde
  • We did some TOO tasks during this downtime such as
    • Realigning the refcav alog83616
      • IMC to down and misaligned MC3 SUS
    • Swapping a dying SUS power supply in the CER
      • I put all the SUS in HAMs 1 & 2 to safe for this
  • 19:25 UTC initial alignment
    • ALS_X (TRX_A_LF_OUT_DQ) would get fuzzy (~6x as thick of a line, 0.1 vs 0.6 min to max) then the WFS error signal would step out, DOF_2_P mainly, then it would come back in
• 20:40 UTC Observing

TITLE: 03/28 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 148Mpc
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 29mph Gusts, 18mph 3min avg
    Primary useism: 0.07 μm/s
    Secondary useism: 0.41 μm/s
QUICK SUMMARY:

RyanC handing over an Observing H1 (going on 2.8hrs).  Violins are elevated, but  they are damping down.  Situation normal.

Was a bit breezy during my drive up here (Corner has some gusts just under 30mph).

I accidently left the ADF off yesterday and set FC de-tuning to -34 vs nominal -36Hz 83597and 83601 where sdfs were accepted. 

• We've not using ADF right now, since we stoped using the sqz angle servo, so we will leave the 322Hz ADF line off for now, tagging DetChar.
• Jennie found 34 vs 36Hz FC detuning are very similar in 83526, so also leaving as is.  

Jennie W, Sheila

While Camilla changed the SRCL tuning (nominal for SRCL1_OFFSET is -191 counts) for squeezer tests today Sheila and I wanted to check if DHARD sensors are still sensitive to DARM. As there is coupling from DARM to DHARD and then DHARD back to DARM, this changes the DARM OLG and thus the sensing function.

I tried to check on whether the sensing function was affected by DHARD currently by looking at the coherence between low frequency PCAL lines below 20 Hz in DARM. The only one we still use is 17.1Hz, there where others used to monitor the low frequency sensing function and the SRC detuning, but these are no longer in use. The other calibration lines still in use below 20Hz are injections on the ETMX suspension.

Francisco looked at this in 2024 in alog #80267, for different offset values of the AS A WFS cwhich are used as a sensor in DHARD. For a setting of 0, which matches the current setting of this offset, the coherence (bottom graph) between DARM and DHARD looks like it is bellow 1 at 17.1 Hz, the SRCL1_OFFSET at the time was -290 counts.

I compared short spectra of DARM with coherences from CAL-DELTAL_EXTERNAL_DQ to ASC-DHARD_P_SM_DQ and ASC-DHARD_Y_SM_DQ. See this image.

For the detunings used, the 17.1Hz line only seems to show up strongly in the -90 count offset, see image of the darm spectra in the top left graph, DARM coherence with DHARD_P in the middle row left graph, DARM coherence with DHARD_Y in the bottom left graph, and the DHARD_P spectra in the top right graph. From the spectra it looks like the 17.1 Hz line is almost buried in the noise for most of the detunings.

Since all these measurements only used ~ 3 mins of data I decided to compare the hour long period from this entry where Camilla had the SRCL1 offset at -290 counts, to a period after commissioning was over when it was back at the nominal of -191 counts.

See this image where I have also added a graph of DHARD_Y spectrum in the middle right of the image.

Purple is the -290 count SRCL offset and Yellow is the -191 count offset. The coupling of the PCAL line to DHARD P and Y does not really change between the two different detunings, but since there is some coupling to DHARD we might want to revisit the AS A WFS offset. Also the coherence from DARM to DHARD_Y (bottom left graph in my first image below) for the same SRCL1 OFFSET (-290 counts, see this image) as Francisco's measurement  was 0.6, compared to the 0.1 coherence he found so that might be a reason to keep looking at this issue.

Finally I include an ndscope of the optical spring frequency (f_S) and the coupled cavity pole frequency (f_C) changing with the detuning. NB: For future me, that optical spring frequency channel defaults to zero when the calculated value is very small I think.

I took advantage of the recent earthquake to tweak the beam alignment into the FSS RefCav from the Control Room to improve the transmission, which had been dropping for the last several days.  With the IMC unlocked the starting RefCav TPD was ~0.660 V, and after the alignment tweak (IMC still unlocked) the TPD is ~0.833 V.

17:42 UTC lockloss from a 6.6 from Cape Verde, holding in down till the motion subsides.

Closes FAMIS26379
Laser Status:
    NPRO output power is 1.864W
    AMP1 output power is 70.39W
    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 51 days, 18 hr 58 minutes
    Reflected power = 22.69W
    Transmitted power = 106.0W
    PowerSum = 128.7W

FSS:
    It has been locked for 0 days 0 hr and 59 min
    TPD[V] = 0.662V

ISS:
    The diffracted power is around 4.2%
    Last saturation event was 0 days 8 hours and 41 minutes ago

Possible Issues:
    FSS TPD is low

Follow up to LHO alog 83200 and LHO alog 80863.

Brian and I thought of a better way of getting the M1 OSEMs in PR3 calibrated relative to the HAM2 GS13s: Use the ISI drives in L, T, V for frequencies above the suspension resonances to get an absolute calibration.

We can use the measurements Jeff took in LHO alog 80863 and project them in the OSEM basis, then use the translational (Longitudinal, Transverse, Vertical) drives to calibrate the OSEMs. Since the GS13s are calibrated to [m] all of the transfer functions (shown in the first attachment) are in [OSEM meters]/[GS13 meters]. At high frequencies (sufficiently above the resonances) the OSEMs should just be measuring (-1)*ISI motion, because the suspension is isolated. The calibration error will depend on how well we are able to drive L,T,V from the ISI without cross-coupling to any other DOF.

Figure 1 attached shows the 6x6 transfer matrix between the ISI drives and OSEMs (inputs are columns, and outputs are rows). We highlight the 6 translational transfer functions that can be used to calibrate the OSEMs in red. The drives seem decoupled enough to do the calibration (for example, we expect to see a length drive only in LF and RT, no motion anywhere else).

Figures 2,3, and 4 show a detail of the 6 transfer functions we will use for calibration, all of them should be scaled to 1 [OSEM m]/[GS13 m]. The scalings are:

The Kepco Power Supply for SUS-C4 started chirping at the end of maintenance today.  By 2pm the chirping is more regular.  The draw on the supply is 7A, typical failing fans last a few days once they get to this stage.  We should replace this one before the weekend, as a target of opportunity.  Down time will be 30 mins start to finish.

WP12406

M. Pirello, F. Clara