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Reports until 10:50, Tuesday 22 October 2024
H1 AOS (ISC, SUS)
joshua.freed@LIGO.ORG - posted 10:50, Tuesday 22 October 2024 - last comment - 10:48, Monday 10 March 2025(80814)
PR3 damping contributions to DARM

J. Freed, S. Dwyer

 

Yesterday we did damping loop injections on all 6 BOSEMs on the PR3 M1. PR3 shows quite alot of coupling in the 10-25Hz range. This is a continuation of the work done previously for ITMX, ITMY, and PR2

As some signals were quite strong, instead of gain of 750, gains of 300 and 600 were collected (300 is labled as low_noise). Also, this time injections were performed in diaggui instead of awggui

The plots, code, and flagged frequencies are located at /ligo/home/joshua.freed/20241021/scrpts. While the diaggui files are at /ligo/home/joshua.freed/20241021/data. This time, 600 gain data was also saved as a reference in the diaggui files (see below), saved in 20241021_H1SUSPR3_M1_OSEMNoise_T3.xml

pr3.png Shows all results for PR3 with the top half being at 300 gain and the bottom being at 600 gain. All sensors showed strong coupling in 10-25Hz range at 600 gain. [LF, RT, T2, T3] showed strong coupling in 10-25Hz range at 300 gain. [SD, T1] instead showed some coupling in the 46-48Hz range at 300 gain. I am unsure if this is signifficant or another noise source while the test was performed.

DiagguiInj.png Shows the set up for the injections in Diaggui. The ramp up and down values in measurment tab were also set to 5sec
 
GPS Times of injections (reference number in diaggui files)
Background time:      1413584423 (ref0 DARM, ref1 LF_out, ref2 RT_out, ref3 SD_out, ref4 T1_out, ref5 T2_out, ref6 T3_out)
LF(low_noise) time:    1413585519
LF time:                        1413585643 (ref7 DARM, ref8 LF_out)
RT(low_noise) time:    1413585954
RT time:                        1413586086 (ref9 DARM, ref10 RT_out)
SD(low_noise) time:   1413586349
SD time:                       1413586510 (ref11 DARM, ref12 SD_out)
T1(low_noise) time:    1413586757
T1 time:                        1413586873 (ref13 DARM, ref14 T1_out)
T2(low_noise) time:    1413587139
T2 time:                        1413587245 (ref15 DARM, ref16 T2_out)
T3(low_noise) time:    1413587436
T3 time:                        1413587545 (ref17 DARM, ref18 T3_out)

 

 

Images attached to this report
Comments related to this report
joshua.freed@LIGO.ORG - 10:48, Monday 10 March 2025 (83268)

Adding a plot to show the individual PR3 BOSEM Contributions

Images attached to this comment
H1 CDS
erik.vonreis@LIGO.ORG - posted 10:43, Tuesday 22 October 2024 (80817)
CNS power supply replaced at EY

Because of the failure of the  CNS power supply at EX, which was the same age as the power supply at EY, and because of some glitches starting to occur with GPS 1 PPS signal from the CNS at EY, I replaced the power supply for the CNS at EY.

 

relevant alogs here:

 

https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=80742

https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=80537

LHO VE
david.barker@LIGO.ORG - posted 10:42, Tuesday 22 October 2024 (80816)
Tue CP1 Fill

Tue Oct 22 10:11:21 2024 INFO: Fill completed in 11min 17secs

Gerardo confirmed a good fill curbside.

Images attached to this report
H1 PSL
ryan.short@LIGO.ORG - posted 08:42, Tuesday 22 October 2024 (80800)
PSL 10-Day Trends

FAMIS 31056

Several things have happened in the past week that show on these trends:

Images attached to this report
LHO General
ibrahim.abouelfettouh@LIGO.ORG - posted 08:10, Tuesday 22 October 2024 (80811)
OPS Day Shift Start

TITLE: 10/22 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 6mph Gusts, 4mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.13 μm/s
QUICK SUMMARY:

IFO is LOCKING (but not for long). We have an 8 hr maintenance day today, expecting the following activities:

H1 CDS
erik.vonreis@LIGO.ORG - posted 07:02, Tuesday 22 October 2024 (80810)
Workstations updated

Workstations were updated and rebooted.  This was an os packages update.  Conda packages were not updated.

H1 General
elenna.capote@LIGO.ORG - posted 17:23, Monday 21 October 2024 (80807)
Lockloss just before observing

I was left in charge of the IFO with directions from Camilla on how to take us into observing and set TJ to the owl operator. There was a lockloss just as I was about to click "observe", approx 12:21 UTC.

H1 ISC
camilla.compton@LIGO.ORG - posted 16:59, Monday 21 October 2024 - last comment - 11:06, Thursday 09 January 2025(80804)
Automatic DARM Offset Steps

Elenna, Camilla

Ran the automatic DARM offset sweep via Elenna's instructions (took <15 minutes):

cd /ligo/gitcommon/labutils/darm_offset_step/
conda activate labutils
python auto_darm_offset_step.py

DARM offset moves recorded to /ligo/gitcommon/labutils/darm_offset_step/data/darm_offset_steps_2024_Oct_21_23_37_44_UTC.txt

Comments related to this report
camilla.compton@LIGO.ORG - 17:02, Monday 21 October 2024 (80805)

Reverted the attached tramp sdf diffs afterwards, see attached. Maybe the script needs to be adjusted to automatically do this.

Images attached to this comment
elenna.capote@LIGO.ORG - 17:28, Monday 21 October 2024 (80806)

I just ran Craig's script to analyze these results. The script fits a contrast defect of 0.742 mW using the 255.0 Hz data and 0.771 mW using the 410.3 Hz data. This value is lower than the previously 1 mW on July 11 (alog 79045), which matches up nicely with our reduced frequency noise since the OFI repair (alog 80596).

I attached the plots that the code generates.

This result then estimates that the homodyne angle is about 7 degrees.

Non-image files attached to this comment
jennifer.wright@LIGO.ORG - 11:06, Thursday 09 January 2025 (82204)

Last year I added some code to plot_darm_optical_gain_vs_dcpd_sum.py to calculate the losses through HAM 6.

Sheila and I have started looking at those again post-OFI replacement.

Just attaching the plot of power at the anti-symmetric port (ie. into HAM 6) vs. power after the OMC as measured by the DCPDs.

The plot is found in /ligo/gitcommon/labutils/darm_offset_step/figures/ and is also on the last page of the pdf Elenna linked above.

From this plot we can see that the relationship between the power into HAM 6 (P_AS) is related to the power at the output DCPDs as follows.

P_AS = 1.220*P_DCPD + 656.818 mW

Where the second term is light that will be rejected by the OMC + that which gets through the OMC but is insensitive to DARM length changes.

The throughput between the anti-symmetric port and the DCPDs is 1/1.22 = 0.820. So that means 18% of the TM00 light that we want at the DCPDs is lost through HAM 6.

 

Non-image files attached to this comment
H1 SQZ
camilla.compton@LIGO.ORG - posted 16:56, Monday 21 October 2024 (80803)
SQZ FC detuning adjusted from -28Hz to -30Hz
Vicky, Camilla
We adjusted the SQZ FC de-tuning from -40Hz to -20Hz,  nominal -28Hz. See attached plot. The best was between -32 and -28Hz  (purple, dark blue, light blue) so we set it to -30Hz and accepted in sdf.
Images attached to this report
LHO General
ibrahim.abouelfettouh@LIGO.ORG - posted 16:30, Monday 21 October 2024 (80802)
OPS Day Shift Summary

TITLE: 10/21 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: TJ (remote)
SHIFT SUMMARY:

IFO is in NLN and COMISSIONING as of 14:40

A lot happened today, mostly related to two brief power outages taking down a few systems. Here's the summary (times in UTC).

Power Outage Story Start (alog 80791)

Pre-Shift:

11:15:48 Local: PSL downed (PMC High Voltage, HAM6 PZT High Voltage, NPRO tripped), Ryan called after 15 mins in READY. Ryan C and Jason troubleshoot, figuring out that it can’t be fixed remotely. OWL alog 80782 They hopefully go back to sleep. IFO in MAINTENANCE.

11:52 Local: Power Glitch 2, the sequel. IFO can’t lock, stays downed.

Shift Start:

14:30: I arrive and realize the PSL has no power and that NDS is being slow. I read the alog and mattermost and saw that Ryan C (OWL Ops) was called and troubleshooting.

14:45: Dave gets on TS and figures out that it was indeed a power glitch (alog bla bla) that took down 2 front end channels, the PMC Hi-Voltage, the NPRO (tripping), HAM6 PZT and potentially caused some NDS troubles. Confusion ensued about what should and shouldn’t have gone down over such a glitch.

15:00: Jonathan joins, goes into the MSR and checks the UPS, and confirms that this had gone on battery for the 2 outage times. This further confirms us that there was definitely bad sitewide power, so it went on battery back-up.

15:00: By now, Dave and Jonathan have understood the outage effects apart from 2 front-end channels going down during the outages, and auto-rebooting shortly thereafter. The two culprits are SUSAUXH2, SUSAUXEX. These aren’t on the UPS so CDS is still confused as to why those went down. Dave cleared the CDS overview alerts and CDS is investigating.

15:05: Fil joins and turns the HAM6 PZT and PMC Hi-Voltage back on.

15:10: Ryan S joins and turns on the PSL, allowing us to lock.

Power Outage Story End, Normal Locking Start:

15:25 Guardian begins initial alignment but FSS glitch (unrelated rabbit hole) happens so we relock the IMC and continue.

16:00 Initial alignment ends and we begin locking! High guardian state LL and alignment issues requiring initial alignment happen, delaying us further (but not for too much longer!)

18:07: NLN Acquired, IFO OBSERVING

19:55: Lockloss alog 80798 (Not PSL, unknown cause).

21:15: Trucks on the move in prep for Earthmoving.

21:40: NLN Acquired, IFO COMISSIONING

23:30: Shift End, Still comissioning


LOG:

Start Time System Name Location Lazer_Haz Task Time End
16:36 SAFE HAZARD LVEA YES !!!!!LVEA IS LASER HAZARD!!!! 03:16
17:39 FAC Karen MY N Technical cleaning 17:39
17:39 FAC Karen Wood Shop N Technical Cleaning 17:56
18:25 PSL Jason, Ryan S Optics Lab Local Preliminary PSL Optics Reconnaissance 18:42
21:25 FAC Earth Movers (TM) Staging Building Behind N Earth Move Prep 22:25
21:26 PSL Jason, Ryan S Optics Lab Local Spare NPRO Work 22:26
H1 SQZ (DetChar, OpsInfo)
camilla.compton@LIGO.ORG - posted 16:18, Monday 21 October 2024 - last comment - 12:38, Thursday 31 October 2024(80801)
SQZ angle servo using ADF turned on

Sheila, Vicky, Camilla

We have turned back on the SQZ angle servo using the ADF at 322Hz. Last briefly tried while testing ADS alignment in ADS in 80194.  Turned on ADF and used 'python setADF.py -f 322'. Then set H1:SQZ-ADF_OMC_TRANS_PHASE to get H1:SQZ-ADF_OMC_TRANS_SQZ_ANG close to zero and checked by stepping the SQZ angle that there is a zero crossing in the ADF measured SQZ angle, plot attached.

The servo adjusts the SQZ angle (H1:SQZ-CLF_REFL_RF6_PHASE_PHASEDEG) via keeping the ADF measured angle (H1:SQZ-ADF_OMC_TRANS_SQZ_ANG) at zero. Setpoint can be adjusted using the ADF phase (H1:SQZ-ADF_OMC_TRANS_PHASE).

Tagging Detchar:  ADF is now on at 322Hz. It was turned all the way off in 79573 by Alan. We can adjust the frequency 50-500Hz if there is a better place for a line.

Note to operators: if you want to run SCAN_SQZANG, the ADF servo will now overwrite the sqz angle. So BEFORE going back to FREQ_DEP_SQZ  you'll want to tweak H1:SQZ-ADF_OMC_TRANS_PHASE (via sqz overview > ADF) to make H1:SQZ-ADF_OMC_TRANS_SQZ_ANG close to zero. Or you can tweak H1:SQZ-ADF_OMC_TRANS_PHASE (via sqz overview > ADF) until the SQZ BLRMs/ DARM is best.

If this ADF servo works well, it should stop the need for running SCAN_SQZ_ANG as often or we can built this into SCAN_SQZ_ANG.
Images attached to this report
Comments related to this report
victoriaa.xu@LIGO.ORG - 13:08, Tuesday 22 October 2024 (80821)

Trends of the ADF servo stabilizing the SQZ angle overnight. Looks good: the ADF SQZ ANGLE servo can hold the maximum squeezing level throughout the lock! Last night was running with the ADF SQZ angle servo + SQZ-IFO AS42 ASC together.

In the first lock of the screenshot, the ADF SQZ ANGLE servo is not yet running, and the squeezing level drifts quite a bit (~0.5-1 dB in ~2 hours, and ends up un-optimal). In the last 2 locks, the ADF SQZ ANGLE servo is running and successfully stabilizes the SQZ angle, though the 2 locks from last night stabilize at different SQZ angles (weird?). Note SQZ ASC is running in both of these locks, so it seems like ASC + ADF SQZ ANG servo work well when used together.

Naoki looked at sqz trends with/without the ADF servo before in LHO:75000. Looking at sqz trends for yesterday, the ADF servo stabilized the SQZ angle in the first ~25 minutes. Then over the first ~2 hours, the ADF servo needed to move the CLF_RF6 demod phase by 5-10 degrees to hold the SQZ angle stable. This implies something like, the optimal injected squeezing angle changed by about 2-5 degrees during IFO thermalization.

Also noting a reference to LHO:77292, where Naoki does an On/Off test with the ADF line at 322 Hz.

Images attached to this comment
camilla.compton@LIGO.ORG - 12:38, Thursday 31 October 2024 (80976)

Checked against the 68139 list, can see that 322Hz is a good frequency for CW. We will look at trying to add this ADF line to the _CLEAN or _NOLINES subtractions. 

H1 ISC (Lockloss, PSL)
ibrahim.abouelfettouh@LIGO.ORG - posted 13:05, Monday 21 October 2024 - last comment - 18:19, Monday 21 October 2024(80798)
Lockloss 19:55 UTC

Lockloss most likely due to PSL FSS Glitch. ASC and IMC lost lock within 63ms of one another, which is suspect. However, it seems AS_A lost lock first, so it might not be FSS related - unsure. Plots below.

Images attached to this report
Comments related to this report
ryan.crouch@LIGO.ORG - 13:33, Monday 21 October 2024 (80799)Lockloss

No FSS tag on the lockloss tool

ryan.short@LIGO.ORG - 18:19, Monday 21 October 2024 (80809)OpsInfo

Tagging OpsInfo: I've added an ndscope template to the lockloss select tool that provides some good channels to look at to help determine if it was caused by the PSL glitches. Running it for this lockloss, I would say this does not look like an "FSS glitch" lockloss (see attached).

Images attached to this comment
LHO VE
david.barker@LIGO.ORG - posted 10:21, Monday 21 October 2024 (80795)
Mon CP1 Fill

Mon Oct 21 10:13:00 2024 INFO: Fill completed in 12min 56secs

Jordan confirmed a good fill curbside.

Images attached to this report
H1 CDS
david.barker@LIGO.ORG - posted 09:07, Monday 21 October 2024 - last comment - 10:27, Monday 21 October 2024(80791)
Site-wide power glitches, reboots of h1susaux[h2, ex]

We had two site-wide power gltiches at 04:15:48 and 04:52:39 PDT Mon 21oct2024.

Both were seen in CS and EX MAINSMON channels. EX saw voltage drop for all three phases, CS saw this for two phases. Voltage drop persisted for about 3 cycles and then recovered.

h1susauxh2 and h1susauxex rebooted on the first glitch at 04:15, their models restarted around 04:17. No other model restarted at these times. There were no IPC errors and no long cpu-runs. We currently don't know why these two susaux machines rebooted by themselves.

 

Images attached to this report
Comments related to this report
david.barker@LIGO.ORG - 09:28, Monday 21 October 2024 (80793)

Opened FRS32411

Notes from Fil:

The HAM6 PZT had to be restarted

Work on Beckhoff DAC power monitors

david.barker@LIGO.ORG - 09:33, Monday 21 October 2024 (80794)

Both GC and CDS UPS units switched to battery backup power for both of these times. The GC unit sent email notifications, the CDS unit did not.

GC was on battery for 5 seconds, CDS for only 1 second.

ibrahim.abouelfettouh@LIGO.ORG - 10:27, Monday 21 October 2024 (80796)

FMC-EX_MAINS Channels seeing the outage at the reported times.

Outage 1: 4:15:48

Outage 2: 4:52:39

Images attached to this comment
H1 SQZ
sheila.dwyer@LIGO.ORG - posted 15:52, Friday 18 October 2024 - last comment - 10:12, Friday 03 January 2025(80747)
homodyne angle sign, initial look at Camilla's data set

Vicky, Sheila

Summary:  Today we learned that frequency independent anti-squeezing is a very good way to determine which sign the homodyne angle is. 

Background: I've been working on using code from Vicky's repo and the noise budget repo to do some checks of a quantum noise model, this is in a new repo here

Details about how this model is made:

The first attached plot illustrates how these models and plots are made.  It starts with a no squeezing time, and an esitmate of non quantum noises from the noise budget, (dark gray, this one is from Elenna's recent run of the noise budget: 80603  ) and an estimate of the arm circulating power along with other parameters set in a quantum parameters file in the same format that is used by the noise budget.  It fits the readout losses by adding a gwinc model of quantum noise with the noise budget estimate of other noises, and adjusting the readout losses of the gwinc model, this is done from 1.5-1.8kHz in this case.

Based on this readoutlosses we get a model of quantum noise without squeezing, and subtract that from the no squeezing trace to get an estimate of the non-quantum noise.  This is enough different from the noise budget one that I've used that as the estimate of the non-quantum noise for the rest of the traces. 

By subtracting this subtraction estimate of the non-quantum noise, it estimates squeezing in dB, and finds a median level of dB from 1.5-1.8kHz for anti-squeezing and squeezing. This should be the same with and without the filter cavity, but in this data set there is slightly more anti-squeezing in the time without the filter cavity, so I've used FIS and FIAS to estimate the nonlinear gain and total efficiency for squeezing.  The nonlinear gain is translated into generated squeezing for gwinc, and the injection losses for squeezing are set so that the injection efficiency* readout efficiency = total squeezing efficieny. 

With this information we can generate models for anti-squeezing and squeezing traces, but fitting the squeezing angle to minimize or maximize quantum noise.  Then for the mid angle traces, the squeezing angle is fit to minimize the residual between the data and the quadrature sum of the subtraction estimate of non quantum noise and the model. We can then look at these plots and try manually changing parameter in the quantum parameter file.

Homodyne angle:

We've been stumped for a while about the excess noise we see with low frequency anti-squeezing, in 79775  I went through old alogs and see that we've had this mismatch of model with our data for a long time.  Today we tried flipping the sign of the homodyne angle and see that low frequency anti-squeezing is much closer to fit both with and without the filter cavity. Compare the 2nd and 3rd attachments to see this.

We still have more work to do on this model, including adding in the additional traces near squeezing and near anti-squeezing that Camilla took, and checking if it can give us any information about arm power (it doesn't seem very useful for that), or the mode mismatches. 

 

 

Images attached to this report
Comments related to this report
sheila.dwyer@LIGO.ORG - 12:06, Monday 21 October 2024 (80797)

I neglected to mention that this is based on the nice data set that Camilla collected here: 80664, and that three is more work to be done with this, checking SRC detuning, mode mismatch, and including the +/- 10 deg data.

 

victoriaa.xu@LIGO.ORG - 12:04, Thursday 24 October 2024 (80820)SQZ

Sumary: seems the current (+) side of DARM is better for FDS, although it is opposite of our previous quantum noise models. But given the current sign is actually better for DARM, the model error doesn't really matter, and it's not really worth changing signs.

The wrong HD angle sign seems to be why none of our quantum noise models, despite fitting all other SQZ angles well, have ever fit FIAS properly. We will update our quantum noise models for the noise budget. Attached are some quantum noise models and DARM plots for Camilla's recent SQZ dataset lho80664.
 

Plots with optimal FDS (optimal fc detuning) for both signs of the homodyne angle: showing 1st just the quantum noise models without adding back non-quantum noise (NQN), and 2nd showing QN models + NQN.

  • Current sign of DARM (+) has solid lines. "Other" sign (-) has dashed lines.
     
  • Homodyne angle is only really obvious for FIAS (freq-indep anti-squeezing, turqoise traces).  It's almost indistinguishable for FIS otherwise (green, yellow, light blue). Marginally noticeable for FDS (but more sensitive to FC optimization).
    • Sheila made a super important observation that FIAS has never fit quantum noise models properly. 
    • Quantum noise models with the "other" (-) sign expect FIAS < No SQZ between 15-100 Hz, and FIAS < FIS between 15-50 Hz. This is not what we have observed with FIAS, despite QN models fitting all other SQZ angles fine.
    • Only flipping the HD angle sign was able to match the QN models to data, suggesting that previous quantum noise models used the wrong sign of the homodyne angle.
    • It turns out this doesn't really matter in real life, but we will update the noise budget models.
       
  • Confusingly, the current (+) side is better with FDS, but the "other" (-) side is better for unsqueezed DARM. See the grey (+) vs. black (-) traces for unsqueezed DARM at +/- 10 deg homodyne angles.
    • Not sure where the notion of a "good side of DARM" comes from
    • Pre-O4a, there was a quick test to lock on the other side of DARM, lho68080...  But maybe this test just shows some technical noises change with the HD angle?
      • In the test, see the plot of how unsqueezed DARM (purple vs. red) is very different below 100 Hz for the two signs, but not in the pway predicted by quantum noise models (grey + black traces).
      • So, seems like this test suggests the +/- sign measured DARM noise differences are more likely technical (non-quantum) noises that change with homodyne angle.

Third attachment (3rd) shows a wider range of homodyne angles, from +15 deg to -10 deg. So far the code for these plots is living here.

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Altogether this is making progress on the quantum noise models for the noise budget!

Summarizing updates and what we're learning:

  • As Sheila said, low freq frequency-independent anti-squeezing (FIAS) ---> homodyne angle (which sign it is + approx how many degrees): see light blue FIAS traces in 2nd plot.
  • As in lho80318 79951, can use the frequency-independent squeezing (+mid-sqz) bronchosaurus (FIS) ---> SRCL detuning. 
  • Subtracted FDS data still WIP as the low frequency quantum noise estimate seems not totally right.
    • Maybe could fit the FC detuning at each SQZ angle (as SQZ angle can affect the RLF-CLF offset for such low (sub-linewidth) FC detunings), but haven't thought about this FDS data much yet.
  • Important model degeneracies remain from having 4 model unknowns: [[ IFO arm power + readout loss, and SQZ NLG + injection loss ]] with which to fit 3 DARM measurements [[ unsqueezed shot noise + anti-squeezing (kHz level) + squeezing (kHz level) ]].
  • Still need to factor in mode-matchings.
Images attached to this comment
sheila.dwyer@LIGO.ORG - 22:41, Monday 28 October 2024 (80877)

Vicky, Sheila

Based on the fit of total squeezing efficiency and nonlinear gain (which is based on subtracted SQZ and ASQZ from 1.5-1.8kHz), and known losses from loss google sheet, we can infer some possible maximum and minimum arm powers using the no squeezing data. 

The first attachment shows the same plot as above, but with the latest jitter noise measured by Elenna in 80808 We noticed this afternoon that there is a problem with the way these jitter noises are being added in quadrature by the noise budget, but we haven't fixed that yet.  In this data set, we have 15.1dB of anti-squeezing and 5.1dB of squeezing from 1.5-1.8kHz, we can use the Aoki equations to solve for nonlinear gain of 14.6 and total efficiency eta for squeezing of 73%.  Since the known readoutlosses are 7.3% and the known squeezer injection losses are 8.8%, this gives us a minimum readout efficency of (eta/(1-known injection loss) = 79% and a maximum of 1-known readout loss = 91.2%.  Using the level of noise between 1.5-1.8kHz with no squeezing (and an estimate of the non quantum noise) we can use these max and min readout efficencies to find min and max circulating powers in the arms. 

These arm power limits will be impacted by our estimate of the non-quantum noise, the homodyne angle, and the SRC detuning.  With 0 SRC detuning, and a homodyne angle of 7 degrees, this resutls in a range of arm powers of 324-375kW.  the estimate of non-quantum noise is the most important of these factors, while SRC detunings large engouh to change these estimates significantly seem outside the range that is allowed by other squeezing mesurements.

  • If I reduce the technical noise estimate from the noise budget by 10% in the ASD, the arm power range is 330-383kW, raising the non quantum estimate by 10% gives a range of 328-375kW.
  • Using a homodyne angle of 10.6 degrees instead of 7 gives an arm power range of 331-383kW. 
  • using an SRC detuning of 0.48 degrees (which is clearly too large based on the mid frequency squeezing) results in a range of powers of 321-372kW. 

I've run the comparison of the model to different squeezing configurations for the low and high range and the nominal parameters (0 SRC, 7 degrees homodyne angle). Frequency independent squeezing and both types of mid squeezing are sensitive to the arm power from 50-100Hz, this comparison shows that the low end of the arm power range seems to have slightly too little arm power and the high range slightly too much.  However these frequencies are also sensitive to homodyne angle and SRC detuning. 

Images attached to this comment
H1 ISC
elenna.capote@LIGO.ORG - posted 13:07, Thursday 10 October 2024 - last comment - 21:18, Monday 04 November 2024(80596)
NB injections taken

I ran the noise budget injections for frequency noise, input jitter (both pitch and yaw) and PRCL. All injections were run with CARM on one sensor (REFL B). The cable for the frequency injection is still plugged in as of this alog, but I reset the gains and switches so we are back on two CARM sensors and the injection switch is set to OFF.

All injections are saved in the usual /ligo/gitcommon/NoiseBudget/aligoNB/aligoNB/H1/couplings folder under Frequency_excitation.xml, IMC_PZT_[P/Y]_inj.xml, and PRCL_excitation.xml.

I realized an intensity noise injection might be interesting, but when I went to run the template for the ISS excitation, I was unable to see an excitation. I think there's a cable that must be plugged in to do this? I am not sure.

*********Edit************

Ryan S. sent me a message with this alog that has notes about how intensity noise injections should be taken. Through this conversation, I realized that I had misread the instructions in the template. I toggled an excitation switch on the ISS second loop screen, when I should have instead set the excitation gain to 1.

I was allowed another chance to run the intensity injections, and I was able to do so, using the low, middle, and high frequency injection templates in the couplings folder.

Also, the Input jitter injections have in the past been limited to 900 Hz, because the IMC WFS channels are DQed at 2048 Hz. However, the live IMC channels are at 16 kHz, so I edited the IMC injection templates to run up to 7 kHz, and use the live channels instead of the DQ channels. That allowed the measurements to run above 900 Hz. However, the current injections are band-limited to only 1 or 2 kHz. I think we can widen the injection band to measure jitter up to 7 kHz. I was unable to make those changes because we had to go back to observing, so this is future to-do item. I also updated the noise budget code to read in the live traces instead of the DQ traces.

Unfortunately, in my rush to run these injections, I forgot to transition over to one CARM sensor, so both the intensity and jitter measurements that are saved are with CARM on REFL A and B.

Comments related to this report
elenna.capote@LIGO.ORG - 17:22, Thursday 10 October 2024 (80603)

I ran an updated noise budget using these new measurements, plus whatever previous measurements were taken by Camilla in this alog. Reminder: the whole noise budget is now being run using median averaging.

I used a sqz time from last night where the range was around 165 Mpc, starting at GPS 1412603869. Camilla and Sheila took a no-sqz data set today starting at 1412607778. Both data sets are 600 seconds long. I created a new entry in gps_reference_times.yml called "LHO_O4b_Oct" with these times.

To run the budget:

>conda activate aligoNB

>python /ligo/gitcommon/NoiseBudget/aligoNB/production_code/H1/lho_darm_noisebudget.py

all plots found in /ligo/gitcommon/NoiseBudget/aligoNB/out/H1/lho_darm_noisebudget/

I made one significant edit to the code, which is that I decided to separate the laser and input jitter traces on the main DARM noise budget. That means that the laser trace is now only a sum of frequency noise and intensity noise. Input beam jitter is now a trace that combines the pitch and yaw measurements from the IMC WFS. Now, due to my changes in the jitter injections detailed above, these jitter injections extend above 900 Hz. To reiterate: the injections are still only band-limited around 2 kHz, which means that there could be unmeasured jitter noise above 2 kHz that was not captured by this measurement.

One reason I wanted to separate these traces is partly because it appears there has been a significant change in the frequency noise. Compared to the last frequency noise measurement, the frequency noise above 1 kHz has dropped by a factor of 10. The last time a frequency noise injection was taken was on July 11, right before the OFI vent, alog 79037. After the OFI vent, Camilla noticed that the noise floor around 10 kHz appeared to have reduced, as well as the HOM peak heights, alog 76794. She posted a follow-up comment on that log today noting that the IFO to OMC mode matching could have an effect on those peaks. This could possibly be related to the decrease in frequency noise. Meanwhile, the frequency noise below 100 Hz seems to be about the same as the July measurement. One significant feature in the high frequency portion of the spectrum is a large peak just above 5 kHz. I have a vague memory that this is approximately where a first order mode peak should be, but I am not sure.

There is no significant change in the intensity noise from July, except that there is also a large peak in the intensity noise just above 5 kHz. Gabriele and I talked about this briefly; we think this might be gain peaking in the ISS, but its hard to tell from alog measurements if that's possible. We think that peak is unlikely to be from the CARM loop. We mentioned the ISS theory to Ryan S. on the off-chance it is related to the current PSL struggles.

The other significant change in the noise budget is the change in the LSC noise. The LSC noise has reduced relative to the last noise budget measurement, alog 80215, which was expected from the PRCL feedforward implementation. Looking directly at the LSC subbudget, PRCL has been reduced by a factor of 10, just as predicted from the FF performance. Now, the overall LSC noise contribution is dominated by noise from MICH. Between 10-20 Hz, we might be able to win a little more with a better MICH feedforward, however that is a very difficult region to fit because of various high Q features (reminder alog).

Just as in the previous noise budget, there is a large amount of unaccounted-for noise. The noise budget code uses a quantum model that Sheila and Vicky have been working on extensively, but I am not sure of the status, and how much of that noise could be affected by adjustments to the model. Many of the noisy low frequency peaks also appear very broad on the timescale of the noise budget plot. We could try running over a longer period of time to better resolve those peaks.

Between 100-500 Hz there are regions where the sum of known noises is actually larger than the measured noise. I think this is because the input jitter projections are made using CAL DELTA L, but the overall noise budget is run on CALIB CLEAN where we are running a jitter subtraction.

Non-image files attached to this comment
victoriaa.xu@LIGO.ORG - 21:18, Monday 04 November 2024 (81059)

I believe these couplings were pushed to aligoNB repo in commit bcdd729e.

elenna.capote@LIGO.ORG - 17:56, Monday 21 October 2024 (80808)

I reran the jitter noise injections, trying to increase the excitation about 2 kHz to better see the high frequency jitter noise. The results were moderately successful; we could probably push even harder. The results indicate that jitter noise is with a factor of 2-3 of DARM above 1 kHz.

I have attached the updated DARM noise budget and input jitter budget. I'm also attaching the ASC budget (no change expected) just because I forgot to attach it in the previous post.

Non-image files attached to this comment
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