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Reports until 07:34, Monday 08 July 2024
H1 General
anthony.sanchez@LIGO.ORG - posted 07:34, Monday 08 July 2024 (78934)
Monday Ops Day Shift Start

TITLE: 07/08 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 155Mpc
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
    SEI_ENV state: SEISMON_ALERT
    Wind: 5mph Gusts, 3mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.05 μm/s
QUICK SUMMARY:

IFO Locked and Observing for 9 Hours.
everything seems to be functioning well.
 

H1 SQZ (SQZ)
nutsinee.kijbunchoo@LIGO.ORG - posted 04:10, Monday 08 July 2024 - last comment - 01:18, Thursday 11 July 2024(78933)
Twin Sisters Rock SHG explained

Daniel, Nutsinee

 

I was intrigued by the Twin Sisters Rock feature in the brand new spare SHG Terry and Karmeng put together so I did a little bit of digging. A quick summary is that we believe the Twin Sisters Rock feature were caused by the phase mismatch between the red and the green inside of the SHG cavity. We believe the dichroic coating of the SHG back mirror might be a suspect since the coating specifications can not be found. However, the phase mismatch doesn't neccessary explain the Mount Saint Helens in the 6 year-old SHG we are currently using. 

The equation used to fit the data came from Gonzalez, Nieh, and Steier 1973 equation1. The equation looks similar to the usual sinc^2 function we know and love except that it's taken the phase mismatch between 532 and 1064 and the air dispersion into account in the cos^2 term. This paper also shows that the experimental data doesn't necessary match the model (Fig.3). The problem is we have to related deltaK*l term to temperature. This was done using Kato and Takaoka 2002. This left us with K_0. The only unknown-ish term here is the nonlinear coefficient d_eff inside of K_0. We used d_eff = 10pm/V as suggested by Leonardi et al 2018. After I wasn't able to get a sensible result Daniel pointed out that unit in K_0 doesn't add up. We replaced K0 with equation1 from Arie et al 1997.

 

The function is also very sensitive to polling length of the crystal. Since we don't have the exact number of the polling length, we picked a polling length such that deltaK is 0 at 34.6 C (optimal phase match condition). The polling length we got was 8.99608um. I believe the crystal polling length according to Raicol is 9um.

 

The function in the end looks like this. I was able to fit Karmeng's Twin Sisters Rock using sensible parameters (d_eff = 10pm/V, circulated 1064 power of 2W, Boyed-Kleinman focusing parameter = 0.9, and a phase shift of Pi/2). Other variations of the spare SHG plots can be explained by shifting this phi variable.

 

We suspect the coating of the SHG back mirror might be to blame. None of the SHG plots found in SURF reports (Nathan Zhao, Andre Medina) look symmetric like they should. 

 

The zip file of the python code is also attached.


If the coating is not to blame, I wonder if it's time we think about redesigning a SHG that is more tolerant to the assembly line errors.

Images attached to this report
Non-image files attached to this report
Comments related to this report
daniel.sigg@LIGO.ORG - 09:22, Monday 08 July 2024 (78939)

For people who are too lazy to read the paper: The dispersion that matters is between the first path and the second path in the crystal. In a simple dual path system, green light will be generated in phase with the red light in the first path, then the two frequencies propagate in air towards the rear mirror, where they are reflected with potentially different phases, and then propagate back to the crystal. According to Gonzalez et al. the dispersion in air for 1064/532 is 27.4°/cm (double passed). Our SHG length is about 5 cm long with a 1 cm crystal. So, the in-air path is of order 4 cm. You need a 90° phase shift to explain the double peak. However, the phase difference of our mirror reflectivity is unknown.

nutsinee.kijbunchoo@LIGO.ORG - 01:18, Thursday 11 July 2024 (79017)SQZ

Daniel Nutsinee

We futher fit a single pass measurements with following parameters:

d_eff = 9pm/V

input power = 60mW

Boyd-Klienman factor = 0.35 (corresponds to w0 = 70um according to Karmeng this is what he sent into the cavity)

The measured power was so low a dark noise is required to offset the model to fit the data correctly. This value is 0.8 uW.

A factor of 1/2 has been added inside of sinc and cos term to convert from double pass to single pass. This agrees with Sheila's equation 3.14.

We also added a factor of 4 to the original function used to fit the double peak measurement to take into account the double pass (4 times the single pass power). A newly acquired Boyd-Klienman factor is 0.56 (corresponds to w0 = 55um, a beam waist dictates by the known cavity parameters). I recalculated circulated power taken into account loss measurement from the escape efficiency. The model suggests 1.7W. I managed to fit using 1.5W. We don't know the modulation depth used to generate the locking signal so this number can be wiggled around a bit. The facator of 4 can also be wiggled around a bit as we don't really know the green loss as it emerges from the cavity. 

 

According to Karmeng the data was taken through a green Bandpass filter with 9% green loss. The data has been multipled by a factor of 1.09 to compensate for this loss.

In summary, our model fits both the Twin Sisters and the single pass measurements.

Images attached to this comment
LHO General
thomas.shaffer@LIGO.ORG - posted 01:00, Monday 08 July 2024 (78931)
Ops Eve Shift End

TITLE: 07/08 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Observing at 154Mpc
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY: One lock loss during the shift. During reacquisition I moved PR3 a little bit to help the comm beat note. After an initial alignment it went straight up and we've been observing for 2.5 hours now.
LOG:

H1 General
thomas.shaffer@LIGO.ORG - posted 20:54, Sunday 07 July 2024 - last comment - 21:50, Tuesday 09 July 2024(78930)
Lock loss 0341 UTC

Lock loss 1404445312

5 hours and 42 mins seems like a standard lock for this week. LSC-DARM saw an odd wiggle before lock loss, normally I see an ETMX output that matches this but I didn't see that this time.

Images attached to this report
Comments related to this report
thomas.shaffer@LIGO.ORG - 22:28, Sunday 07 July 2024 (78932)

Back to Observing at 0528 UTC.

I ended up slightly moving PR3 P from -122.2 -> -121.6 and Y from 98.8 -> 98.6. This brought the beatnote up to around -14.5dBm, up from the -18 or so that I started at, and ALSX power moved up as well. when DRMI locked POP18 looks to be higher than it was the last handful of locks over the last few days. I ran through an initial alignment and then it went right up.

oli.patane@LIGO.ORG - 21:50, Tuesday 09 July 2024 (78990)

EX L3 does oscillate 16 ms before DARM sees the lockloss, although it might be possible that the slight drop (marked in green) is DARM seeing it??

Images attached to this comment
H1 AOS
robert.schofield@LIGO.ORG - posted 16:30, Sunday 07 July 2024 (78929)
LVEA ready for laser safe

I have replaced the original viewport covers so the LVEA is ready to go to laser safe.

At the last minute I finally found a beam on the MC baffle by HAM3. The beam is on the +X side of the baffle, near the hole for the viewport for the PRM camera. I will see if it moves with the CP when I return.

LHO General
corey.gray@LIGO.ORG - posted 16:28, Sunday 07 July 2024 - last comment - 08:34, Monday 08 July 2024(78918)
Sun DAY Ops Summary

TITLE: 07/07 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Aligning
INCOMING OPERATOR: TJ
SHIFT SUMMARY:

Similar shift to yesterday (except we're around 102degF!), with a 4-5hr lock and 2-3hr reacquisition (with rough locking for the first 90min). 

(Since Observing time is precious, I didn't even think of running a calibration since L1 & V1 were UP all the times I could have run a calibration.)

Robert was onsite as well as JennyW for an RRT shift.
LOG:

Comments related to this report
camilla.compton@LIGO.ORG - 08:34, Monday 08 July 2024 (78936)Lockloss

Jennie Wright points out that the 19:34 lockloss 1404416083 has the glitch we've been seeing in DARM/length in the 100's ms before the lockloss 73818 73565. Her plot attached. Ianin Morton is preaping a lockloss tag for this: issue #219.

Images attached to this comment
H1 PEM
robert.schofield@LIGO.ORG - posted 16:22, Sunday 07 July 2024 (78925)
Slow bias changes during observation completed; New ESD bias settings: ITMX 0V, ITMY -40V (-4.0 in offset window)

Commissioning time has been reduced recently by lock losses and other issues, so I have been trying a new technique for determining the ITM biases that minimize coupling of electronics ground noise. I have been making slow adjustments of the bias during observation, recording the times of those slow changes, and then monitoring the coherence between DARM and the current clamp on the electronics grounding cable in the CER for the new settings.

The times of the slow changes during observation mode, and the bias setting I have tried, are listed in 78791, 78767, 78734 and this log. The figure compares the original settings for O4b, the setting that we guessed would be best, 0V,0V, and the setting that was consistently better, ITMX: 0, ITMY: -40 V (a setting of -4 in the offset window).

Start of change (GPS)

End of change (GPS)

ITMX bias at start (V)

ITMX bias at end (V)

ITMY bias at start (V)

ITMY bias at end (V)

1404317823

1404317979

0

-20

0

-22

1404319278

1404319453

-20

20

-22

-20

1404341414

1404341526

0

0

0

-20

1404342991

1404343117

0

0

-20

-40

1404344533

1404344655

0

40

-40

-40

1404413221

1404413147

0

0

0

-40

Non-image files attached to this report
LHO General
thomas.shaffer@LIGO.ORG - posted 16:13, Sunday 07 July 2024 (78928)
Ops Eve Shift End

TITLE: 07/07 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Observing at 152Mpc
OUTGOING OPERATOR: Corey
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 10mph Gusts, 8mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.06 μm/s
QUICK SUMMARY: Corey got us relocked and we've been running good for an hour.

H1 DetChar (DetChar)
bhaskar.verma@LIGO.ORG - posted 16:02, Sunday 07 July 2024 (78927)
DQ_Shift Summary 06/24/2024 - 06/30/2024

Link to report

 

H1 General
corey.gray@LIGO.ORG - posted 15:13, Sunday 07 July 2024 (78926)
More SDF Diffs, Back to Observing after 2hrs34min

Once again, a diff for ALS-Y_WFS (Basically ACCEPTED filter which was originally enabled for the recent lock).

Then had an additional Diff for a TRAMP for LSC-XARM.  (see attached for both.)

Images attached to this report
LHO General
corey.gray@LIGO.ORG - posted 12:13, Sunday 07 July 2024 - last comment - 12:42, Sunday 07 July 2024(78923)
Mid-Shift Status (Sun DAY)

H1's been locked almost 4.25hrs (kind of expecting it to lose lock any minute given H1's behavoir since Tues).  Around 95degF outside.

Comments related to this report
corey.gray@LIGO.ORG - 12:42, Sunday 07 July 2024 (78924)

Lockloss at around 4.6hrs.  Not going to waste time and immediately run an Initial Alignment since green arms don't look good.

H1 General
corey.gray@LIGO.ORG - posted 09:53, Sunday 07 July 2024 (78922)
ALS-Y Diffs ACCEPTED To Get To OBSERVING This Morning

To get to Observing shortly after the beginning of the shift this morning, I needed to ACCEPT ALS-Y WFS filter changes (see attached).  These appeared to have occurred around the steps of DHARD_WFS & PARK_ALS_VCO (but I don't see this channel during those states).

The channels changed are:
H1:ALS-Y_WFS_DOF_3_Y

H1:ALS-Y_WFS_DOF_3_P

And ACCEPTED their FM9's ("-14dB" filter)

Images attached to this report
H1 CDS
david.barker@LIGO.ORG - posted 08:50, Sunday 07 July 2024 (78920)
Improved reporting of models built using non-production RCG versions

I have colour coded the FE RCG overview MEDM to show non-production RCG models with a red box. Clicking on the purple RCG box on the CDS overview will now open the RCG Overview MEDM.

Images attached to this report
LHO VE
david.barker@LIGO.ORG - posted 08:23, Sunday 07 July 2024 (78919)
Sun CP1 Fill

Sun Jul 07 08:19:21 2024 INFO: Fill completed in 19min 16secs

Images attached to this report
LHO General
corey.gray@LIGO.ORG - posted 07:41, Sunday 07 July 2024 (78917)
Sun DAY Ops Transition

TITLE: 07/07 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Aligning
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 7mph Gusts, 4mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.05 μm/s
QUICK SUMMARY:

H1 was past 25W when I arrived (thanks to an awakened RyanS for the 2-clicks for ALS!).  Waiting for H1 to get back to NLN.

Post Timing-Error (and pesky Tues Main), H1 has been riding rough; last 24hrs roughly 3-4hr long locks with 2-3 lock acquisitions.  We'll see how today's data point looks for h1!  With these short locks not sure we'll thermalize long enough to run a calibration, but we'll see if there's an opportunity (when other detectors are down).

H1 General
ryan.short@LIGO.ORG - posted 07:28, Sunday 07 July 2024 (78916)
Ops Owl Shift Summary

H1 called for assistance at 13:30 UTC because it was stuck trying to lock ALSY. I gave ETMY two clicks in yaw and that seemed to be all it needed; H1 is relocking smoothly and up to PREP_DC_READOUT.

H1 General
thomas.shaffer@LIGO.ORG - posted 00:13, Sunday 07 July 2024 - last comment - 09:05, Monday 08 July 2024(78913)
Lock loss 0642

Lock loss 1404369750

Again, not seeing much of anything on any of the plots. Another 4-5 hour lock.

Comments related to this report
vladimir.bossilkov@LIGO.ORG - 07:22, Sunday 07 July 2024 (78915)

Hey so I had a quick squiz whether your locklosses might be PI related. The regularity of your lock lengths is very suspicious.

You had at least one lockloss from a ~80296 PI on July 5th just after 6am UTC.
Since then you have been passing through it, exciting it, but surviving the PI-Fly-By.

On those plots you will notice broader a feature that moves slowly up in frequency and excites modes as it passes (kinda vertical-diagonalish on those plots) that smells like the interacting optical mode to me.

Last couple of days you have lost lock when that feature reaches ~80306, where there's a couple of modes which grow a little in amplitude as the broad feature approaches.
It is hard for me to say which mechanical mode had the super high gain that would make you lose lock on the scale of seconds [because these modes would move wildly in frequency at LHO as I discuss in the link at the end of this line], but its in that ballpark,and I quote myself: avoid at all costs.
Please investigate if this is PI and whether you need to tweak up your TCS.

EDIT: Longer lock on the 8th makes me think 80kHz PIs are probably fine. Worth double checking carefully in the 20-25 kHz region since your mode spacing looks pretty high. It might be subtle to see in the PI plot on the lock pages since that aliases a lot of noise all over the place.

camilla.compton@LIGO.ORG - 09:05, Monday 08 July 2024 (78937)ISC

Thanks for pointing us to these PI locklosses out Vlad, Ryan also caught one of them in 7886778874.

The lockloss website for the July 5th 637UTC lockloss 1404196646 tags OMC_DCPD and can see elevated noise on the "PI Monitor" dropdown on the website too, maybe peaks at 15 and 30kHz.

Maybe the reason we saw these around July 5th is as our PR2 moves 78878 changed the amount of circulating power we saw in the arms, plot attached.
We still need to check if we're seeing any PI locklosses in the last ~2 days  with the higher circulating power: 1404445312  has the OMC_DCPD tag and shows some elevated noise in the PI bands, 1404346170 and has the OMC_DCPD tag but no elevated noise in the PI bands
Images attached to this comment
vladimir.bossilkov@LIGO.ORG - 08:40, Monday 08 July 2024 (78938)

Edit2: There are some elevated peaks at many frequencies before a lockloss I chose to look at, but nothing alarming enough. The largest peak change is something at 3619 Hz, which could be a red herring or aliased from a much higher frequency, but I don't know what that peak is.

H1 SEI (SEI)
neil.doerksen@LIGO.ORG - posted 18:35, Thursday 04 July 2024 - last comment - 09:14, Friday 12 July 2024(78869)
Earthquake Analysis : Similar onsite wave velocities may or may not cause lockloss, why?

It seems earthquakes causing similar magnitudes of movement on-site may or may not cause lockloss. Why is this happening? Should expect to always or never cause lockloss for similar events. One suspicion is that common or differential motion might lend itself better to keeping or breaking lock.

- Lockloss is defined as H1:DRD-ISC_LOCK_STATE_N going to 0 (or near 0).
- I correlated H1:DRD-ISC_LOCK_STATE_N with H1:ISI-GND_STS_CS_Z_EQ_PEAK_OUTMON peaks between 500 and 2500 μm/s.
- I manually scrolled through the data from present to 2 May 2024 to find events.
    - Manual, because 1) wanted to start with a small sample size and quickly see if there was a pattern, and 2) because I need to find events that caused loss, then go and find similarly sized events we kept lock.
- Channels I looked at include:
    - IMC-REFL_SERVO_SPLITMON
    - GRD-ISC_LOCK_STATE_N
    - ISI-GND_STS_CS_Z_EQ_PEAK_OUTMON ("CS_PEAK")
    - SEI-CARM_GNDBLRMS_30M_100M
    - SEI-DARM_GNDBLRMS_30M_100M
    - SEI-XARM_GNDBLRMS_30M_100M
    - SEI-YARM_GNDBLRMS_30M_100M
    - SEI-CARM_GNDBLRMS_100M_300M
    - SEI-DARM_GNDBLRMS_100M_300M
    - SEI-XARM_GNDBLRMS_100M_300M
    - SEI-YARM_GNDBLRMS_100M_300M
    - ISI-GND_STS_ITMY_X_BLRMS_30M_100M
    - ISI-GND_STS_ITMY_Y_BLRMS_30M_100M
    - ISI-GND_STS_ITMY_Z_BLRMS_30M_100M
    - ISI-GND_STS_ITMY_X_BLRMS_100M_300M
    - ISI-GND_STS_ITMY_Y_BLRMS_100M_300M
    - ISI-GND_STS_ITMY_Z_BLRMS_100M_300M
    - SUS-SRM_M3_COILOUTF_LL_INMON
    - SUS-SRM_M3_COILOUTF_LR_INMON
    - SUS-SRM_M3_COILOUTF_UL_INMON
    - SUS-SRM_M3_COILOUTF_UR_INMON
    - SUS-PRM_M3_COILOUTF_LL_INMON
    - SUS-PRM_M3_COILOUTF_LR_INMON
    - SUS-PRM_M3_COILOUTF_UL_INMON
    - SUS-PRM_M3_COILOUTF_UR_INMON

        - ndscope template saved as neil_eq_temp2.yaml

- 26 events; 14 lockloss, 12 locked (3 or 4 lockloss event may have non-seismic causes)

- After, usiing CS_PEAK to find the events, I, so far, used the ISI channels to analyse the events.
    - The SEI channels were created last week (only 2 events captured in these channels, so far).

- Conclusions:
    - There are 6, CS_PEAK events above 1,000 μm/s in which we *lost* lock;
        - In SEI 30M-100M
            - 4 have z-axis dominant motion with no motion or strong z-motion or no motion in SEI 100M-300M
            - 2 have y-axis dominated motion with a lot of activity in SEI 100M-300M and y-motion dominating some of the time.
    - There are 6, CS_PEAK events above 1,000 μm/s in which we *kept* lock;
        - In SEI 30M-100M
            - 5 have z-axis dominant motion with only general noise in SEI 100M-300M
            - 1 has z-axis dominant noise near the peak in CS_PEAK and strong y-axis domaniated motion starting 4 min prior to the CS_PEAK peak; it too only has general noise in SEI 100M-300M. This x- or y-motion which starts about 4 min before the peak in CS_PEAK has been observed in 5 events -- Love waves precede Rayleigh waves, could be Love waves?
    - All events below 1000 μm/s which lose lock seem to have a dominant y-motion in either/both SEI 30M-100M / 100M-300M. However, the sample size is not large enough to convince me that shear motion is what is causing lockloss. But it is large enough to convince me to find more events and verify. (Some plots attached.)

Images attached to this report
Comments related to this report
beverly.berger@LIGO.ORG - 09:08, Sunday 07 July 2024 (78921)DCS, SEI

In a study with student Alexis Vazquez (see the poster at https://dcc.ligo.org/LIGO-G2302420, we found that there was an intermediate range of peak ground velocities in EQs where lock could be lost or maintained. We also found some evidence that lock loss in this case might be correlated with high microseism (either ambiant or caused by the EQ). See the figures in the linked poster under Findings and Validation.

neil.doerksen@LIGO.ORG - 09:14, Friday 12 July 2024 (79070)SEI

One of the plots (2nd row, 2nd column) has the incorrect x-channel on some of the images (all posted images are correct, by chance). Patterns reported may not be correct, will reanalyze.

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