This morning we changed the demod phase of the POP 9 sensor.  The overall summary is that this has a very similar impact to adding a PRCL offset, reducing the PRCL to REFL RIN coupling, and slightly increaing power in the PRC, but not changing the coupling of PRCL noise to DARM.  I've turned off the offset, added a new phasing, and updated the PRCL to SRCL subtraction in the LSC input matrix.

More details:

I used a 702.1 Hz frequency noise injection, (template found in userapps/lsc/h1/templates/phase_LSC_sensors_frequency_exc.xml)  and adjusted the POP9 phase to reduce the appearance of the frequency injection in Q (screenshot shows initial to final settings change in Q peak).  I used Elenna's template to make a PRCL injection and measure the coupling to RELF RIN and DARM during this move, see screenshot.  Adjusting the phase reduced the PRCL to REFL RIN coupling in a way that's similar to what Elenna has seen by adjusting the PRCL offset (see 79989 for example). Also similar to what Elenna has seen with the PRCL offset, this has very little impact on the PRCL to DARM coupling.  The ndscope screenshot shows how this impacted REFL and POP powers, you can compare the time when I turned off the offset to the time when I tried reverting the phase to the original setting after finding the new setting, the two things have a simlar impact on the reflected power and the power in the PRC. 

One interesting observation is that the phase that minimized the PRCL to REFL RIN coupling (as shown by the sign flip in the transfer function), is different from the phase that minimzed the frequency injection coupling to POP 9Q, by 2 degrees.  I've left this at the phase that minimizes REFL RIN coupling.  The impact on the power build ups is small enough that this two degree difference can't be evaluated using them. 

Another observation is that the change in phasing doesn't seem to have an impact on the PRCL spectrum, spectrum screenshot. 

Lastly, I did another PRCL excitation to measure the coupling to POP 45 and POP9 I, using the template in userapps/lsc/h1/templates/SRCL/SRCL/SRCL_input_matrix_git_rid_of_PRCL.xml  (excuse the typo).  I used this measurment to try to zero the PRCL coupling to SRCL ((POP45/PRCL)*MTRX_5_3 + (POP9I/PRCL)*MTRX_5_1 = 0, and found that this matrix element needed to be updated from 0.1185 to 0.1408.  This was last updated by Jenne Driggers in 70919.  The update reduced the SRCL to PRCL coupling by about 20dB, shown here. 

Lastly we edited the guardian to not use the PRCL offset, and update the PRCL to SRCL input matrix element, and accepted the new matrix and phasing in SDF (in the observe file, and now also in the safe file).

Lockloss at 21:17 UTC

FAMIS 31052

No major events of note this week. PMC reflected power seems to be holding mostly steady now, like we started to see last week.

Related detchar request: #172

Key points
11.9 Hz comb is present in some ASC, IMC and ISI-HAM5 channels:

• H1_ASC-DHARD_P_OUT_DQ
• H1_IMC-DOF_4_Y_IN1_DQ
• H1_IMC-REFL_DC_OUT_DQ
• H1_ISI-HAM5_BLND_GS13RZ_IN1_DQ
• H1_ISI-HAM5_BLND_GS13X_IN1_DQ
• H1_ISI-HAM5_BLND_GS13Z_IN1_DQ

Fscan data on 2024-04-08 was analyzed with a 2-week duration. 11.9 Hz comb is common at both observatories. The 1st and 3rd harmonics (11.9hz and 35.7hz) are the strongest peaks to study.

Details
*The method is adapted from #77990.

The stamp-pem-comparison tool was used first to pick out possible witnesses from low-resolution STAMP-PEM data. The result of 2024-06 -- 2024-08 is shown in Figure 1. I then followed up the analysis with week-long Fscan data on 2024-04-08. This date was chosen because the comb appeared strong then, according to alog 72866. Figures 2-7 are the coherence plots for the witness channels listed above. The interactive plots for some more auxiliary channels, plots of data from June, speclong data and data spanning 2 weeks can be found under https://ldas-jobs.ligo-wa.caltech.edu/~zhiyu.zhang/11.9Hz_appearance/. These other plots confirm the same channels. The comb is not visible in one day in these auxiliary channels.

The results of this analysis only apply to LHO for now, but the same method can be applied to LLO data.

Sheila and I are still trying to determine if the a2l script can be helpful, or made helpful, and understand our coupling from these changes to DHARD and CHARD. We ran it today with both C&D HARD showing higher coherences with our current lock (attachment from Ryan C's alog80244). After running the script the largest change was to ITMY Y gain (-0.28 diff). This helped out DHARD from 15-35Hz, but made CHARD worse in 10-21Hz. We were then going to try and tune common by hand to see if we could make any difference, but we lost lock.

We decided to update the gains with the script results since this did help out our DHARD. Perhaps an acceptable trade off for now. Values for the Y gains have been updated in lscparams and SDF, but P was close enough that I left them alone.

We are starting planned commissioning at 15:30 UTC. Some of the tasks to be worked on are:

• A2L gains - Try to reduce DHARD coherence
• PEM HAM1 shaking
• SRCL offset
• Measure AS42 sensing matrix

Mon Sep 23 08:11:39 2024 INFO: Fill completed in 11min 35secs

Jordan confirmed a good fill curbside.

TITLE: 09/23 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 151Mpc
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 3mph Gusts, 1mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.15 μm/s
QUICK SUMMARY:

• We've been locked for 9:40
• Low wind, ground motion
• Comissioning work planned for today

TITLE: 09/23 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 156Mpc
INCOMING OPERATOR: Oli
SHIFT SUMMARY: Two locklosses this shift, one from a PI ringup and another from an earthquake. Otherwise a quiet shift and lock acquisition has been straightforward.

• 22:45 - H1 starts observing
• 00:16 - Lockloss from PI 24 - alog80238
• 01:18 - Observing
• 03:22 - Lockloss from nearby EQ - alog80240
• 04:45 - Observing

Lockloss @ 03:22 UTC - link to lockloss tool

I originally thought this lockloss was from a M5.4 EQ from Chile that was predicted to hit at this time, but now that the USGS site has updated and looking at how sudden and hard-hitting the lockloss was, I now suspect this was from a M3.2 EQ from Desert Aire, WA, a mere 20 miles northwest of the site.

Since this quake was so close, ground motion calmed down quickly and I've started the relocking process.

Lockloss @ 00:18 UTC - link to lockloss tool

PI mode 24 rung up 90 minutes into the lock stretch and caused this lockloss. I tried manually damping after seeing Guardian be unsuccessful, but I also wasn't able to find a phase which brought this mode down at all before losing lock (I did not get to trying different gains).

TITLE: 09/22 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 136Mpc
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY: The range has peaked at 164 Mpc in the first 2 locks of the day. 2 locklosses this shift, the range isn't so great this current lock, high freq SQZing looks bad.

LOG:                                                                                                                                                 

• 09:54 UTC lockloss  ~10:00 lock
  • 11:13 UTC Observing
• 15:22 UTC lockloss  4:10 lock
  • I had to adjust PRM and SRM during PRMI and DRMI
  • 16:35 UTC Observing
• 20:53 UTC lockloss from a HAM3 CPS glitch (H2 & V2) 4:21 lock (contacted Jim)
  • 21:05 UTC HAM3 ISI trip, I reset it, it then settled in isolated, then glitched and retripped 7 minutes later
  • alog80232
  • 21:39 UTC The alignment (xarm esp) seemed bad after this so I ran an IA
  • 22:46 UTC Observing

TITLE: 09/22 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 146Mpc
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 15mph Gusts, 9mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.13 μm/s
QUICK SUMMARY: H1 just got back to observing about 15 minutes ago. High frequency noise looks particularly bad this lock, so once H1 is thermalized I may try some SQZ alignment to improve it.

• Wind slightly elevated, other ground motion low
• All other systems nominal

20:53 UTC lockloss

There were HAM3 CPS glitches on verbal before the LL, and PRM was the first saturating suspension from the LL tool.