I started injecting jitter lines in the periscope PZT: pitch at 215 Hz, amplitude 20, yaw 135 amplitude 10, in H1:IMC-PZT_PIT and H1:IMC-PZT_YAW. The yaw line is very well visible in DARM, the pitch line is much smaller. This is as expected, since yaw is the main jitter that couples.

I tried to move the AS_C YAW offset to move the SRC, without any change in the jitter line amplitude, with offsets as large as 0.2.

I then tried to move the OMC alignment. It looks like there is little effect on yaw, but some effect on pitch. Bummer. More on a later alog with a full OMC alignment change.

I measured again MICH and SRCL FF. I could fit a MICH filter that improves the subtraction. SRCL is still work in progres.

The new MICH FF filter is loaded into FM1, it's better so I'll put in in guardian.

We now have the new DARM offloading configuration up and running, and fully calibrated, so we can do a direct comparison of the old offloading (Old DARM) and new offloading (New DARM) using GDS-CALIB_STRAIN.

As pointed out by Elenna, the new DARM configuration improves the low frequency noise level. See first plot.

The old DARM configuration induced non-stationary noise at low frequency, as visible in the spectrogram in the second plot, and also in the whitened spectrogram in the third plot (where DARM is whitened with the median of the Old DARM configuration, to show at the same time the reduction in noise and the better stationarity).

Those same spectrograms also show that the new DARM configuration makes the low frequency noise more stationary.

Other comparison plots:

• DARM BLRMS at low frequency with old and new DARM
• ESD drive RMS
• scatter plot of DARM BLRMS vs ESD drive RMS, that shows a clear relation in old DARM

Finally, the last two plots show bicoherence of DARM with the ESD drive in old DARM and new DARM: nothing is visible in new DARM.

TITLE: 03/16 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: None
SHIFT SUMMARY:

IFO is in NLN and COMISSIONING - 17:56 Hour Lock!

Conducted the following measurements with instructions from comissioners;

1. SRC Detuning and Sensing - alog 76457

2. Calibration Suite and Broadband Measurements - H1_calibration_report_20240316T161823Z - alog 76455

3. DARM Offset Test - alog 76454

Other:

EX Pressure EX_X5_PT526 MOD1 PRESS TORR is showing a yellow alert on the vacuum alarm handler - this is still the case and the trend just shows that it has been zero forever (years). - don't know what's going on here, but do not think it's serious.
 

LOG:

22:05 (ish) UTC - Gabriele arrived on site

Louis, Ibrahim

The test was successful and results can be found in:

/ligo/gitcommon/noise_recorder/data/pcaly_noise/

/ligo/gitcommon/noise_recorder/data/pcaly_noise/

with some variant of today's date (03/16/24) and the title SRCLOFFSET

Screenshots show trends of both the SRC Offset and the SQZ Phase over the course of the test.

Sat Mar 16 10:11:58 2024 INFO: Fill completed in 11min 54secs

Louis, Ibrahim

Both ran without successfully without lockloss.

Approximate Broadband Start Time: 16:00 UTC

Simulines Start Time GPS: 1394641120

Simulines End Time GPS: 1394642411

Files Written:

2024-03-16 16:39:53,184 | INFO | File written out to: /ligo/groups/cal/H1/measurements/DARMOLG_SS/DARMOLG_SS_20240316T161823Z.hdf5
2024-03-16 16:39:53,191 | INFO | File written out to: /ligo/groups/cal/H1/measurements/PCALY2DARM_SS/PCALY2DARM_SS_20240316T161823Z.hdf5
2024-03-16 16:39:53,196 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L1_SS/SUSETMX_L1_SS_20240316T161823Z.hdf5
2024-03-16 16:39:53,201 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L2_SS/SUSETMX_L2_SS_20240316T161823Z.hdf5
2024-03-16 16:39:53,205 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L3_SS/SUSETMX_L3_SS_20240316T161823Z.hdf5

IFO Calibration Screen and H1 Calibration Report are attached

DARM Offset Test:

Test was run without issues and upon checking the PCAL X and Y Excitation screens, the only differences I can see before vs. after are in the OSC_TRAMP Times:

PCALX: OSC TRAMP (sec) OSC1 was 3 and went to 5

PCALY: OSC TRAMP (sec) OSC1-9 were 10 and went to 5.

I reverted these to their before values - everything else is the same (screenshots below).

TITLE: 03/16 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 1mph Gusts, 0mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.23 μm/s
QUICK SUMMARY:

IFO is in NLN and COMISSIONING (9hr 44 min lock)

Other:

EX Pressure EX_X5_PT526 MOD1 PRESS TORR is showing a yellow alert on the vacuum alarm handler - will investigate.

*H1:PEM-CS_DUST_PSL101 - dust counts did not change, please investigate - showing same alert as yesterday.

The squeezers performed some optimization of the squeezing today (76426), and we have our New DARM control implemented (76420). The calibration has been updated (76406), so I think we have a reliable look at our current sensitivity. Our current range is just above 150 Mpc, going between 151 and 156 on the sensmon range. This is lower than our best O4a range. However, looking at a comparison from a good O4a time, you can see pretty well where we are missing sensitivity.

I have attached three plots, comparing the CAL_DELTAL_EXTERNAL trace that is calibrated and with no cal lines on from today, to GDS CALIB STRAIN NOLINES and CLEAN taken on Jan 7 when we had close to 160 Mpc. I made a plot each to compare DELTAL/NOLINES and DELTAL/CLEAN and all three together, so the differences are more evident.

Clearly the low frequency range has a big improvement, which I think is mostly attributable to the new DARM. It's also much more stationary (76341). Great work! There is an unfortunate peaky structure around 25-30 Hz; this was present in O4a too and I think we are just revealing more of it with the improvement. There's a chance these are triple suspension bounce modes (70778). There appears to be some extra peaks and noise between 40-50 Hz.

The jitter noise appears to have gotten worse around 100 Hz, and this is especially evident in the GDS CLEAN comparison because a large portion of what is subtracted in CLEAN during O4a was jitter noise. It is now worse and also unsubtracted at the moment. Also, it appears we have lost some sensitivity from 200-500 Hz, which I think we can attribute to squeezing not being exactly tuned for that region.

Meanwhile, the squeezing improvements are incredibly significant at 2 kHz and above, where the squeezing team says they are reaching 5 dB of squeezing! This is fantastic, but given the loss at 300 Hz, I wonder if it's possible to optimize for the bucket (just making this suggestion based on what I've heard from the sqz team in the past).

Some additional notes for further commissioning work:

• we have found an AS A WFS DC offset that minimizes DHARD Y coupling, but creates a problem for the sqz ASC. We should evaluate whether the squeeze team can work around this, because it will likely help the low frequency sensitivity but not the squeezing. (76407)
• With the low frequency improvement, we are probably reaching the level of the ASC noise again. It is unlikely loop optimization will help us further, so adjustments like A2L gains and WFS offsets are a good way to go to improve sensitivity (76363, 76414)
• The LSC noise is more likely to limit us, and we may need a better understanding of where we are limited by LSC noise if our feedforward tuning cannot improve at all frequencies (76409)
• We should consider if changing the input pointing can lower the jitter noise. This will probably be a pain because this will change the alignment of the whole IFO (76359, 76417)

Georgia, Trent

To get the finesse of the omc as a function of the pzt voltage (in order to double check the pzt voltage calibration). OMCscan.py has shortcoming in that it doesn't like when there are more than three carrier 00 peaks so to get three carrier 00 peaks that were included in my initial scan I had to seperate the data into two "bins". I had the GPS time 1393542033 with a duration of 80 to get the first two peaks and the GPS time 1393542063 with a duration of 60 to get the second and third peaks. The links of the GPS times are the corresponding pzt calibrations. The links in the finesse are the zoomed in plots for the corresponsing peaks. To get the plots we ran OMCscan.py and fit_peak_w_args.py

Sweeps from /ligo/gitcommon/psl_measurements/templates:

IMC OLG UGF 69 kHz
CARM OLG UGF 17 kHz

[Elenna, Louis]

We reduced the amplitudes of the L2 and L3 SUS calibration lines. Both lines were way too loud after moving to the new DARM loop offloading configuration. The settings we ended up on are below:


Line | Freq | Gain | DELTA_L/SUS_EXC uncertainty 

L2   | 16.4 Hz | 1.5 | 0.0058
L3   | 17.6 Hz | 0.061 | .0046


For each step I changed all of the following channels:
H1:SUS-ETMX_L2_CAL_LINE_CLKGAIN, H1:SUS-ETMX_L2_CAL_LINE_SINGAIN, H1:SUS-ETMX_L2_CAL_LINE_COSGAIN, H1:CAL-CS_TDEP_SUS_LINE2_COMPARISON_OSC_CLKGAIN, H1:CAL-CS_TDEP_SUS_LINE2_COMPARISON_OSC_SINGAIN, H1:CAL-CS_TDEP_SUS_LINE2_COMPARISON_OSC_COSGAIN

I'm attaching the CAL-CS SUS Line screens for both lines. Red boxes highlight the gains that we adjusted.

With the offset on the AS_A WFS centering, that should lower DHARD_Y coupling to DARM:

https://ldas-jobs.ligo-wa.caltech.edu/~gabriele.vajente/bruco_1394535464_DARM

Indeed, DHARD_Y coherence with DARM is much lower. Interestingly, now CHARD_Y coherence seems higher.

In other news, there is some coherence with MICH, but hopefully the retuned FF filter will help with that.

Coherence with input jitter witness is also large, see for example the PSL periscope

[Louis, Gabriele]

We did again the noise injections for retuning the MICH FF, analysis and fit will follow tomorrow.

[Louis, Gabriele]

The DHARD_Y to DARM coupling always showed two regimes: a steep coupling below 20-30 Hz, and a flatter coupling above 20-30 Hz. We've been able to change the flatter coupling above 20-30 Hz by changing the ITMT Y2L coefficient.

Today we confirmed a suspicion: the steep low frequency coupling is due to length to angle coupling at the AS WFS. We changed the beam position on the WFS by adding an offset to the WFS centering (H1:ASC-AS_A_DC_YAW_OFFSET) and saw a change in the DHARD_Y to DARM coupling.

A value close to -0.14 gives the minimum coupling below 20 Hz. we now have two independent knobs to minimize the DHARD_Y to DARM coupling at all frequencies.

Incidentally, the higher frequency couping is now lower than yesterday, with the same ITMY Y2L coefficient of -1.65

We did a scan of the AS_A_WFS Y centering from -0.2 to -0.1 in steps of 0.01, an analysis will follow tomorrow:

-0.200: 1394510627 - 1394510727
-0.190: 1394510777 - 1394510877
-0.180: 1394510927 - 1394511027
-0.170: 1394511077 - 1394511177
-0.160: 1394511227 - 1394511327
-0.150: 1394511377 - 1394511477
-0.140: 1394511527 - 1394511627
-0.130: 1394511677 - 1394511777
-0.120: 1394511827 - 1394511928
-0.110: 1394511978 - 1394512078
-0.100: 1394512128 - 1394512228
 0.000: 1394512278 - 1394512378

We are leaving a value of -0.14 in the WFS offset

Naoki, Dhruva, Nutsinee

Yesterday we had only 3dB squeezing at IFO so we checked squeezing at homodyne. Although the visibility is good (98.5%), the squeezing was only 4.5dB at homodyne with 6dBm CLF6. We reduced the CLF power and recovered 8dB squeezing as shown in the attached figure.

The CLF6 was reduced from 6dBm to -42dBm and the 8dB squeezing was obtained with -38dBm CLF6. The CLF6 between -38 and -20 dBm gave similar squeezing so we set it at -24dBm, which is similar to O4a value and corresponds to 8uW CLF_REFL_LF_OUTPUT. The squeezing at IFO is recovered to 4.5dB with -24dBm CLF6.

Note that the LLO also saw the better squeezing at IFO with less CLF power in LLO70072.

We had 6.5dB squeezing at homodyne in 76040 and 4.5dB squeezing at IFO in 76226 with 6dBm CLF6 before. The question is why we lost squeezing at homodyne and IFO this week with same CLF power? The commissioning list in 76369 might give us a clue.