TITLE: 08/25 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 152Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY: Detector still Observing and has been Locked for 37hrs 37mins.

Throughout my shift there were a few instances where a GW candidate came in on GraceDB with the EARLY_WARNING tag(but very high FAR), and then possible subthreshold GRB candidates that came in closely after would cause Verbals to announce them.

Also, around 8/25 4:36ish UTC, I noticed that the lock clock said to stand down, but there had been no alert on Verbals, and going to GraceDB, there hadn't been any GRB events in the previous couple of hours.

23:00UTC Detector in Observing and Locked for 29.5 hours

23:19 SubGRBTargeted on Verbals E432118
23:22 SubGRBTargeted on Verbals E432119
     - A bunch more SubGRBTargeted on verbals, along with some getting repeated alerts a few minutes later

23:24 Earthquake mode activated for earthquake from Japan (and from off Oregon Coast)
23:24 Back to CALM

23:39 Earthquake mode activated from another earthquake from off the coast of Oregon
23:49 Back to CALM

4:36ish - 4:43UTC lock clock says to Stand Down

LOG:

no log

We're going on 34 hours of being Locked and Observing at 147Mpc.

Genevieve and I did about a dozen scattering injections in the LVEA on July 20th and 21st. For this round of injections we inserted the retro-reflector into the guillotine port for 10 seconds, removed for 10 seconds and repeated 6 times. We are still working through the data on those but it appears as if we had some scattering noise on HAM3 in the left guillotine port. There is an increased noise source present when the reflector is inserted. I did more scattering injections yesterday on HAM3 and HAM6 during commissioning and will parse through that data soon. 

Spectrograms of accelerometer on HAM3 and DARM:
-Acc
-DARM
-Stacked with red lines around the time the reflector was inserted and noise was present

TITLE: 08/24 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 150Mpc
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 13mph Gusts, 9mph 5min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.08 μm/s
QUICK SUMMARY:

Taking over for Ryan C. Detector in Observing and has been Locked for 29.5 hours. The EX Pirani pressure gauge, VAC-EX_X2_PT524B_PRESS_TORR, is still down even though it should have come back up by now (tagging vacuum team even though they know already).

L. Dartez, J. Kissel

We're investigating some issues with time-dependent correction factors (TDCFs) as computed by the front-end vs. GDS, and reminding ourselves of the parameters that define the "smoothing out" of the computation. In particular the uncertainty threshold against which the live uncertainty is compared.

Apparently, all front-end thresholds are set at 5% uncertainty.

    H1:CAL-CS_TDEP_CAVITY_POLE_F_C_GATE_UNC_THRESH       0.05
    H1:CAL-CS_TDEP_CAVITY_POLE_KAPPA_C_GATE_UNC_THRESH   0.05
    H1:CAL-CS_TDEP_D2N_SPRING_F_S_GATE_UNC_THRESH        0.05
    H1:CAL-CS_TDEP_D2N_SPRING_Q_S_GATE_UNC_THRESH        0.05
    H1:CAL-CS_TDEP_KAPPA_PUM_GATE_UNC_THRESH             0.05
    H1:CAL-CS_TDEP_KAPPA_TST_GATE_UNC_THRESH             0.05
    H1:CAL-CS_TDEP_KAPPA_UIM_GATE_UNC_THRESH             0.05
(Remember, the live uncertainty is defined by taking each calibration line's coherence, coh, with DARM_ERR, converting it to uncertainty via sqrt([1-coh]/[2*Navg*coh]), where Navg is determined by the FFT length -- see LHO:69175 for a recent review of this calculation.)

I could make up a story from my foggy memory as to why the front-end thresholds are set at 5% (and not 0.5%, like we expected -- and like what we *think* the GDS pipeline's threshold is), but I'll spare you. They've been this way since Apr 2021.

Attached is the time-series comparison between GDS (in red) and Front-end (in gray) computed \kappa_C for the 24 hour period after July 31 2023 00:00 UTC. The gray, front-end trace shows the characteristic ~3 hour thermalization transient we've come to know and love from our 76W IFO (see e.g. LHO:69796). The red trace, doesn't show this, and it's in fact frozen at the "last good value" by the GDS gating system -- because it's uncertainty threshold is much lower than 5%. 

We presume that this is because the detector noise was pretty DARM bad during this time period -- see 24-hour statistics on the sensitivity in second attachment.

TITLE: 08/24 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 150Mpc
INCOMING OPERATOR: Oli
SHIFT SUMMARY: Pretty quiet day, no commissoning activites today. We stayed locked and Observing the whole shift, 29:36 lock time as of 23:00UTC

LOG:

Following up on TJ's alog from 8/17 (72293), it was noted that a garbage truck at LSB was quite loud. The seismometers in the LVEA clearly picked up the noise, and it seems to coincide with noise in DARM. It's hard to be certain with only one signal, but it probably warrants further investigation.

Spectrogams attached of one seismometer and DARM for 2 minute time span around when noise was reported:
-Of signal
-Zoomed in with boxes on noise regions
-Stacked with some boxes around correlated noise

Thu Aug 24 10:16:47 2023 INFO: Fill completed in 16min 42secs

Travis confirmed a good fill curbside.

TITLE: 08/24 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 148Mpc
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 3mph Gusts, 1mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.08 μm/s
QUICK SUMMARY:

• CDS/Dust/SUS/VAC looks good (VAC EX pressure gauge is still red)
• We've been locked for 21:31, in Observing since 22:55UTC yesterday

TITLE: 08/23 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 152Mpc
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY:  Nice smooth shift with Ryan taking H1 to Observing minutes before the shift and H1 staying in Observing the whole shift (w/ only one M5.4 Mariana Islands EQ of note & not an issue).  There was also O4's 34th Gravitational Wave candidate (S230824r).
LOG:  N/A

TITLE: 08/23 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 152Mpc
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 11mph Gusts, 7mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.13 μm/s
QUICK SUMMARY:

H1's been locked for just over 6hrs (& in observing the last ~30min and L1 joining slightly after us).  Fairly nice environmentally (w/ winds calming in the last hour). 

Alarm Handlers:

• PSL's 101 300nm channel continues to be in alarm state, but the alarm's set really low and this correlates with winds picking up.
• EX CP8's Pirani pressure gauge (H0:VAC-EX_X2_PT524B_PRESS_TORR) continues to be RED (at 0 Torr) since tues morning (the 524B cold cathode gauge is GREEN/normal), and we have an OPS note about it coming back within 1-2 days.

Link to the report:

Important Highlights

• IFO averaged an observing time of around 76%; low observing time (< 60%) on Aug 15 and Aug 16; high observing time (> 90%) on weekend (almost 100% observing time on Aug 19)
• The range fluctuated between 140 - 150 Mpc when in observing mode
  • Exceptions: range momentarily hit 160 Mpc on Aug 17 due to HVAC being turned off (Aug-17); range momentarily hit ~ 155 Mpc on Aug 18
• Fscan line count was consistently below 600 on Aug 14-18; line count was significantly higher (a bit below 650) on Aug 20
• Hveto winners over the week were:
  • (5 days) H1:PEM-EX_VMON_ETMX_ESDPOWER48_DQ
  • (Tied for 3 days each) H1:SUS-ETMX_L3_OPLEV_YAW_OUT_DQ, H1:LSC-POP_A_LF_OUT_DQ, H1:SUS-ETMX_L3_OPLEV_PIT_OUT_DQ
  • Other winners: H1:ASC-CHARD_Y_OUT_DQ (Aug 14), H1:PEM-EX_VMON_ETMX_ESDPOWER18_DQ (Aug 15, Aug 20), H1:ASC-REFL_A_RF45_I_YAW_OUT_DQ (Aug 16), H1:LSC-REFL_A_LF_OUT_DQ (Aug 16), H1:ASC-REFL_A_RF9_I_YAW_OUT_DQ (Aug 17), H1:ASC-Y_TR_A_NSUM_OUT_DQ (Aug 17)
• Significantly fewer high-SNR (at least ≥ 8) glitches for all days this week compared to Aug 13
• Particularly significant excess noise in PEM during observing time:
  • Aug 14, 15, 17, 18, 19, 20: Significant low frequency noise (< 40 Hz) in many ACC and acoustic channels
  • Aug 16, 17, 19, 20: Corner ACCs (only Corner ACCs on Aug 16, but more ACCs on the other days) all seem to have a zig-zag pattern/line around 30-40 Hz
  • Aug 19: Loud burst at 17:00 UTC in YMAN beam tube motion (but not in the XMAN or other corner tube accelerometers); it is also present but not as strong in BSC1 and in the YCRYO floor ACCs
    • Curious short-lived dip in range at same time (17:00 - 17:10 UTC)
• Aug 17: Turning off the HVAC confirmed that the HVAC chiller pumps are the source of the faint 52 Hz line consistently seen this week and in past weeks (Aug-18)
• Strong horizontal lines around 1000 Hz, 500 Hz, and 102 Hz (covers a broader range of frequencies than the other two lines) show up consistently as the IFO enters lock (Aug-14, Aug-18)
  • These lines do not show up for most of Aug 20 as IFO did not lose lock since ~ 4:30 UTC the previous day
• Aug 20: Drastic range dip to slightly below 140 Mpc from 11:30 - 13:00 UTC, especially given how clean the strain noise spectrogram looks and with no clear ground motion correlation
  • In the frequency interval ~ 100 Hz - 170 Hz, the integrated strain at the start of the dip (12:00 UTC) tends to be higher than the integrated strain much earlier on (8:10 UTC)
  • Additional short-lived range dip (also going below 140 Mpc) at 3:30-4:30 UTC seems to correlate with ground motion

Other Highlights

• PEM:
  • Aug 15: Loud burst in BSC10 (Z) that lasted about two hours (16:00 - 18:00 UTC)
  • Aug 17: In EY acoustic noise, loud burst a bit after HVAC was turned off (HVAC turning off between 15:30 - 16:00 UTC shows up as a vertical blue band in most ACCs), as well as dark horizontal line between 20-30 Hz from 10:30 - 16:00 UTC
  • Aug 18: Three vertical blue bands in End BSCs and Acoustic from 16:00 - 17:00 UTC
  • Aug 20: Dark horizontal line between 20-30 Hz in most ACCs + Acoustic
  • Aug 20: Loud burst between 1:00 - 2:00 UTC in the End Floor channel
• Aug 19: More medium-duration templates with new_SNR between 8-9 compared to previous days
• Consistently fewer coincidences in the Hveto channels for each day this week compared to several days the previous week

After chatting with Sushant at LLO, I followed his advice to add a bit of weight to the minimization metric at 60 Hz, and was able to get cleaning parameters that do a pretty good job of subtracting jitter and laser frequency noise, but don't inject noise at the 60 Hz line.  The jitter subtraction is a little less good than alog 72276, but it's important to not inject noise with the cleaning, so this is a good balance. I similarly retrained the laser noise, and with both of them on (while other commissioning work was ongoing), I see good subtraction and no noise injection at 60 Hz.  This is shown in the first attachment.

After having collected a bit of time with the jitter and laser noise subtracted, I retrained the LSC modulated cleaning.  Unfortunately, when trying it in the online system (I don't have the offline mimic of this working yet), it needs a similar mysterious minus sign much like the jitter subtraction needed until I recompiled the code last week.  I'm starting to suspect that the LSC NonSENS c-code also needs to be regenerated and recompiled, and hopefully that will solve my minus sign issue.  Anyhow, when the LSC noise estimate has that minus sign in place, it gives a reasonable amount of subtraction, as shown in the second attachment.

The third attachment shows the improvement (when blue is above pink/orange) in range from the cleaning.  Around 19-20 hours on that plot I'm just subtracting jitter and laser noise.  Around 21 hours I add in LSC subtraction, and we get back to ~150 Mpc.  So, likely our LSC FF is becoming mistuned, and we'd benefit from either retuning the LSC FF or finally implementing the NonSENS subtraction. 

The cleaning review committee meets tomorrow.  All of this is turned off when the IFO is in Observing until given approval by the review committee.

While some calibration work was ongoing, I turned off the HAM1 -> CHARD feedforward, so that Elenna / Gabriele can potentially retrain the filters to make further improvements now that Jim has installed new HAM1 seismic feedforward filters (alog 72393).

The switch H1:HPI-HAM1_TTL4C_FF_OUTSW was off from 23 Aug 2023 22:03:47 UTC to 22:55:20 UTC. 

TITLE: 08/23 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 151Mpc

INCOMING OPERATOR: Corey
SHIFT SUMMARY: Optics lab and PSL anteroom dust alarms have been off and on today just as yesterday.

Lock#1:

Lockloss at 15:33UTC

Lock#2:

No flashes on DRMI or PRMI, tried check mich, no luck, went into IA. I had to help out Yarm during green arms (ENABLE_WFS state on Yarm) by tapping pitch a microradian.

NLN at 17:20UTC with no interventions, in Observing at 17:35UTC.

Out of Observing at 19:08 for planned commissioning work. I brought us to NLN_CAL_MEAS to take a calibration measurement at 21:33UTC

Back into Observing at 22:55UTC

LOG:                                                                                                                                                                                                  

I reduced the amplitude of the 17.1 Hz PCALY calibration line. This is a continuation of LHO:71945.



Channel                                                             Old Gain            New Gain            Reduction Factor
=================                                     =========        ===========        ===========
H1:CAL-PCALY_PCALOSC1_OSC_SINGAIN          250                   115                              2.17


The changes have been saved to observe and safe snap files in the SDF system.

Naoki, Vicky

Today we tested higher generated SQZ level and FC detuning, summary screenshot here. We turned up non-linear gain from NLG 11 to 17, so gen sqz level from 14.7dB to 17dB, and very barely got more sqz (< 0.2dB?). We set it back to the "normal" 80uW operating point, leaving the injected sqz level unchanged. We ended up changing FC detuning from -25 Hz to -28 Hz. Notes:

• no sqz 1376852952 - 1376853678.  (OPO taken down at 1376853301)
• Re-injected FDS with OPO_TRANS = 95uW (NLG=17, Gen Sqz = 16.95 dB). Adjusted OPO temp to maximize CLF_RF6_ABS and watching SQZ level in DARM.
• 19:37 - 19:41 High NLG at 95uW, fc detuning -28
  • Barely more sqz, probably not more than 0.2 dB sqz at high freq (including trying different angles, after adjusting OPO temp). I was a little surprised, I thought we would have seen more squeezing with the NLG increase..
• At FC detuning = -28 Hz (was -25 Hz), set OPO TRANS back to 80 uW.
• Ran a slow-ish sqz angle sweep from about 1376855983-1376856425. Will try using this slower sweep to improve calibration fits of the clf_demod_phase to the true sqz angle.
  • Reminder: clf_demod_phase is what we use to change the sqz angle (e.g. 71902), but they are not the same thing. See 49026 for equation relating sqz angle and clf demod phase.
• Leaving FC detuning at -28 Hz (was -25 Hz). Naoki accepted this in SDF. Not sure if this is really better, but it's possible, so we will try this for now.
   
• Briefly tried to see whether there is excess noise with the beam diverter open, opo unlocked, and pump flipper blocked (clf shutter open). In principle, if there's scatter from the squeezer that's above DARM, maybe we would see it in this configuration? From the blue trace in this screenshot of no-sqz traces, I don't see a noticeable amount of excess noise when comparing this state with the regular "no squeezing" reference taken ~1 hour ago, but I didn't take a back-to-back proper no-sqz reference, so the traces are not as comparable as I'd like.

I stole the filter that Huyen used for her HAM1 feedforward test, and tried it on the LHO HAM1, with a gain tweak of 17% (ie I multiplied by a gain of 1.17 vs LLO ) to match my measurements and it seems to work well. I was having difficulty with my hand fits with excess low frequency noise or gain peaking where I tried to roll my filters off.  First plot shows the on/ off asds for the HAM2 sts and the HAM1 Z HEPI l4cs. I don't know if I quite believe the improvement below 1 hz is due to the feedforward, but Huyen said she got improvement kind of 1-70hz and that seems to be the case here as well. I'm leaving this filter on overnight, to get good low frequency data.

Second image compares one of my filters(red) with the (green) LLO filter. One thing I still don't understand is that my filters have often caused broad low frequency noise, but the LLO filter doesn't seem to. We don't currently have a noise model for HEPI that allows modeling the ff performance, that would help a lot.

DCPD saturation then lockloss