Fri Oct 20 10:11:27 2023 INFO: Fill completed in 11min 23secs

Gerardo confirmed a good fill curbside.

FAMIS 19998

The PMC_TRANS_OUTPUT looks like it may be slowly trending downwords, the PMC_TEMP_OUTPUT stepped up by about .4 on the 12th. Theres a spike in a lot of channels 3 days ago which was tuesday maintenance when Jason went in to realign the RefCav alog73513.

TITLE: 10/20 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 156Mpc
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 3mph Gusts, 1mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.36 μm/s
QUICK SUMMARY:

• Vacuum alarm X_BT_Manifold, tagging VE
• All other systems look good, microseism is trending down, winds low
• cdsws13 is acting up a bit, being really slow, firefox is also not working well on it

TITLE: 10/20 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 159Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY: Quiet night overall. We're Observing and have now been Locked for 11hours 45mins.
LOG:

23:00UTC Detector in Commissioning and has been Locked for 4hrs

23:14 Trash truck put down trash bin loudly
23:16 Trash truck leaving site

00:44 Earthquake mode activated
00:54 Back to CALM

Tony and I noticed a strange pattern of noise that happened twice in close succession in the OAF-RANGE_RLP_1_OUTPUT BLRMs channel(bandpassed between 10-20Hz)(attachment1-red trace). It starts around 10/19 22:58UTC and ends at 23:08 before then repeating between 23:08 and 23:20.

We know that the garbage truck was onsite today and slammed a dumpster down at ~23:14 before leaving the site at 23:16, so we think this could be caused by the truck's movement onsite. The OAF-RANGE_RLP_{2,3,4}_OUTPUT BLRMs channels (20-34, 38-60, and 60-100Hz, respectively) all saw a spike at 23:14:41(attachment2-orange,yellow,green traces), and Lance's previous alog(72404) shows clear noise in GDS-CALIB_STRAIN up to ~50/60Hz.

However, this noise being caused by the truck would mean that the truck was onsite for 20 minutes, which seems way too long. Additionally, I did a quick look back at when the garbage truck was onsite from Lance's alog (08/24 and left at 23:05UTC), and although I did not see anything that looked similar during when the truck was onsite, I did find a similar-ish pattern that happened between 08/24 23:11 and 23:36UTC(attachment3-red trace), ten minutes after the truck would have left, meaning that the noise could not have been caused by the truck. But this could also be my brain trying to fit this random noise into a pattern that resembles the noise from today, so please take with a grain of salt.

Observing at 160Mpc and have been Locked for 8 hours.

Everything is looking good and nothing to report.

FAMIS 25961

Generating BSC pngs...

    
BSC high freq noise is elevated for these sensor(s)!!!
    
ITMX_ST2_CPSINF_H3    
ITMX_ST2_CPSINF_V1    
ITMX_ST2_CPSINF_V3    

    
    
Generating HAM pngs...
Merging pngs to final PDF

final PDF is attached

It looks like HAM7_CPSINF_V3 is elevated compared to the rest of the HAM spectras, but looking back to https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=73295 HAM 7 seems to generally have more noise than the rest of the HAMs on that channel.

TITLE: 10/19 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 161Mpc
INCOMING OPERATOR: Oli
SHIFT SUMMARY: Locked for 3.3 hours after losing lock with the same odd LSC-DARM wiggle (alog73592). On relock, the squeezer had an issue locking and Vicky needed to step in. All is well now.
LOG:

• 1750 Out of Observing for short SQZ tuning
• 1752 Observing
• 1813 Lock loss
• 1941 Observing

TITLE: 10/19 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 163Mpc
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 10mph Gusts, 8mph 5min avg
    Primary useism: 0.06 μm/s
    Secondary useism: 0.43 μm/s
QUICK SUMMARY:

Locked for 4hours and Observing. Everything sounds normal but I'll keep an eye on the squeezer.

On 16 Oct, I noticed bursts of noise at about 32 Hz in the h(t) spectrogram on the LHO main Summary page. These noise bursts are circled in Fig. 1. They have appeared every day since then and appear to be growing more prominent. A specific burst at 15:30 will be used as an example and is shown in Fig. 2.

Fig. 3 shows the spectrum for 15 minutes around the noise burst (blue) of Fig. 2 compared to the previous 15 minutes with no noise burst (orange). The spectral feature is clearly associated with the noise burst.

Previous Summary Pages show these noise bursts from time to time. Previous significant aLog mentions just prior to ER15 of 32 Hz noise are here [LSC feedback-related peaks have been visible in DARM at 32Hz and 40Hz. it was demonstrated that they could be removed by notch filters in MICH servo] with a follow up here [Identifying the moment when the 32Hz peak couples to MICH (POP45)]. These aLogs contained spectra which matched those in Fig. 3  and also pointed to ASC MITCH CONTROL. Fig. 4 shows that the noise bursts in ASC MITCH Pitch control appear at the same times and at the same frequency as in h(t). While Fig. 4 shows the pitch component, the yaw component looks the same.

Several of the CS ACC channels visible on the Summary Pages had noise bursts at the same times and frequency as DARM. They are (using the Summary Page designation): LVEA floor motion [HAM1, Y], HAM2 Z, HAM3 Y, HAM4 X, HAM6 Z , BS X FLOOR, BS Y FLOOR, BS Z FLOOR, HAM1 Y FLOOR, HAM6 Z FLOOR, PSL TABLE X,Y, and Z, PSL  Periscope.

Spectrograms comparing the noise burst of Fig. 2 in h(t)  to spectrograms of the HAM1 floor accelerometers were made using the same color range for the ACC channels. The comparison using the Y component is shown in Fig. 5. The turquoise lines point to the ends of the burst in both spectrograms. The noise burst is not visible for the X component while, though strong, there is less contrast for the Z component because the ambient noise level is much higher. There is no evidence that the noise burst is stronger in the HAM1 ACCs than in the other ACCs. It has just been used as an example.

This aLog has used several normalized spectrograms. This means that an apparently stronger noise burst from day to day might just indicate lower ambient noise. This is demonstrated in Fig. 6 comparing the spectrum including a noise burst on 2023-10-16 15:25:00 (orange) to one at 2023-10-19 11:05:00 (blue). The later time shows a very comparable peak amplitude at 32.25 Hz but lower ambient noise.

The problem was due a remote server restart, which has now been resolved. I have added the two pnsndata stations (OTR and LAIR) back into the code and restarted Picket Fence at 14:00. Note that the map is now back to full scale.

Naoki, Sheila, Camilla, Vicky

Summary: After yesterday's crystal move LHO:73535, we re-aligned SQZT7, and now see 8 dB SQZ on the homodyne, up to measured NLG=114 without a phase noise turnaround! This fully resolves the homodyne loss budget, there is 0 mystery loss remaining on the homodyne, from which we can infer 0 mystery losses in HAM7. Back to the IFO afterwards, after 1 day at this new crystal spot, squeezing in DARM is about 4.5dB - 4.8dB, reaching almost 5dB at the start of lock.

We first re-aligned the homodyne to the IFO SQZ alignment, which reached 4.8dB SQZ in DARM yesterday, so we are more confident the alignment back through the VOPO is not clipping. In yesterday's measurements, we had a sign error in the FC-ASC offloading script, which brought us to a bad alignment with limited homodyne squeezing, despite high 98% fringe visibilities. Attached is a screenshot of homodyne FC/ZM slider values with FC+SQZ ASC's fully offloaded (correctly), to which the on-table SQZT7 homodyne is now well-aligned. After Sheila re-aligned the homodyne to the screenshotted FC/ZM values, fringe visibilities are PD1 = 98.5% (loss 3.1%), PD2 = 97.8% (loss 4.2%).

We then did an NLG sweep on the homodyne, from NLG=2.4 (opo trans 20uW) to NLG=114 (opo trans 120uW). Measurements below and attached as .txt, DTT is attached, plots to follow.

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

unamplified_ir = 0.0014 (H1:SQZ-OPO_IR_PD_LF_OUT_DQ with pump shuttered)

NLG = amplified / unamplified_ir (opo green pump un-shuttered)

@80uW pump trans, amplified = 0.0198 (at start, 0.0196 at end) --> NLG 0.0198/0.0014 ~ 14

@100uW pump trans, amplified = 0.0046 (at start, 0.0458 at end) --> NLG 0.046/0.0014 = 33

@120uW pump trans, amplified = 0.16 --> NLG 0.16/0.0014 = 114

@60uW pump trans, amplified = 0.011 (at start, 0.0107 at end) --> NLG = 7.86

@40uW pump trans, amplified = 0.0059 (at start, 0.0059 at end) --> NLG = 4.2

@20uW pump trans, amplified = 0.0034 (at start, --- at end) --> NLG = 2.4

All measurements had PUMP_ISS engaged throughout; we manually tuned the ISS setpoint for different NLGs. For low NLG (20uW trans) we manually engaged ISS. LO power (shot noise) drifted ~5% over the measurement, see trends.

NLG Sweep Procedure:

• Measure LO shot noise
• Measure amplified seed power, adjust OPO TEC temp to maximize NLG for given OPO GREEN TRANS
• Toggle Seed/CLF Back to CLF on SQZT0, shutter CLF, open HD path (Toggle HD Path Green). Measure Mean SQZ with CLF shuttered
• Unshutter CLF, "LOCKED CLF", "LOCKED HD". Set SQZ demod angle to minimize AHF on HD (aka minimize H1:SQZ-ADF_HD_DIFF_IQSUM_RMS). Measure SQZ dB
• Rotate H1:SQZ-CLF_REFL_RF6_PHASE_PHASEDEG to maximize ADF from same H1:SQZ-ADF_HD_DIFF_IQSUM_RMS. Measure ASQZ dB
• Toggle HD back to OPO IR PD (red). Toggle CLF --> Seed. Re-measure NLG. Change OPO GREEN TRANS by changing PUMP_ISS setpoint & repeat.

DTT saved in $(userapps)/sqz/h1/Templates/dtt/HD_SQZ/HD_SQZ_8dB_101823_NLGsweep.xml

With high primary and secondary useism the SEI_ENV node has been transitioning to earthquake mode based on higher peakmon (H1:ISI-GND_STS_CS_Z_EQ_PEAK_OUTMON) signals, but not due to an actual earthquake. I've raised this threshold from 600 to 850 for now. It looks like the waves should calm down in about a day so I'll plan to revert this tomorrow.

Peter, Sidd

Counts_to_volts = 40/2^16

Transimpedance = 20,000

Responsivity = 0.35

Oplev_from_ETMX = 5.6 m

Diode_area = 10x10 mm^2

Angle_from_test_mass = 7.6 degrees

Power_scatter = Counts x Counts_to_volts x (1/Responsivity) x (1/Transimpedance)

Solid_angle = diode_area/(Oplev_from_ETMX)^2

BRDF = Power_scatter/(Arms_Power x solid_angle x cos(angle_from_test_mass) )

I compared the ETMX Oplev BRDF between the 75 W and 60 W configuration. The details are below, the first three days are when LHO operated with 75 W and the last three days are with 60 W input power. I do not find any significant change in the ETMX Oplev BRDF. 

The calculation is in the notebook

Today at 4:45 UTC the annulus ion pump for GV8 went down to zero-ish, not a common failure, perhaps the ion pump controller failed, we (vacuum group) will take a look at the system as soon as permissible.

To see if the OM2/beckhoff coupling is a direct electronics coupling or not, we've done A-B-A test while the fast shutter was closed (no meaningful light on the DCPD).

State A (should be quiet): 2023 Oct/10 15:18:30 UTC - 16:48:00 UTC. The same as the last observing mode. No electrical connection from any pin of the Beckhoff cable to the OM2 heater driver chassis. Heater drive voltage is supplied by the portable voltage reference.

State B (might be noisy): 16:50:00 UTC - 18:21:00 UTC. The cable is directly connected to the OM2 heater driver chassis.

State A (should be quiet): 18:23:00- 19:19:30 UTC or so.

DetChar, please directly look at H1:OMC-DCPD_SUM_OUT_DQ to find combs.

It seems that even if the shutter is closed, once in a while very small amount of light reaches DCPDs (green and red arrows in the first attachment). One of them (red arrow) lasted long and we don't know what was going on there. One of the short glitches was caused by BS momentarilly kicked (cyan arrow) and scattered light in HAM6 somehow reached DCPDs, but I couldn't find other glitches that exactly coincided with optics motion or IMC locked/unlocked.

To give you a sense of how bad (or not) these glitches are, 2nd attachment shows the DCPD spectrum of a quiet time in the first State A period (green), strange glitchy period indicated by the red arrow in the first attachment (blue), a quiet time in State B (red) and during the observing time (black, not corrected for the loop).

FYI, right now we're back to State A (should be quiet). Next Tuesday I'll inject something to thermistors in chamber. BTW 785 was moved in front of the HAM6 rack though it's powered off and not connected to anything.

Vicky and I went to SQZT7 while calibration work was happening, to follow up on some of our observations from 72525 (and Vicky's comment). 

Polarization issue:

​​​​​​​With the seed dither locked, we placed a PBS before the half wave plate in the homodyne sqz path and measured 67.2uW transmitted (vertical pol) and 750uW reflected (horizontal) (817uW total, 8% in the wrong polarization, 16.5 degrees polarization rotation).  After the half wave plate we measured 5.48uW transmission through the PBS (vertical) and 802uW reflected (horizontal) ( 807uW total, 0.7% in the wrong polarization, polarization less than 5 degrees away from horizontal).  We also placed the PBS right at the bottom of the periscope, and there measured 70uW transmitted and 820uW before the PBS was inserted (8.5% in the wrong polarization, 17 degrees polarization rotation away from horizontal).  This would not limit the squeezing measured on the homodyne since we are able to correct it with the HWP, but measuring the same polarization rotation at the bottom of the periscope suggests that the beam could be coming out of HAM7 with this polarization error, which would look like an 8% loss to the squeezing level in the IFO. 

In Sept 2022, during the vent for the OM2 swap, we measured the throughput of the seed beam from HAM7 to HAM6 65110, which agreed well with the only loss between HAM7 and HAM6 being the 65.6% reflectivity of SRM, and suggests that there was not an 8% loss in the OFI at that time. 

Loss on SQZT7 (not bad):

Comparing the total power measurements here, we have 820uW at the bottom of the periscope, and 807uW measured right before the homodyne, so we have something like 1.6% loss on SQZT7 optics (small compared to the type of loss we need to explain our squeezing level).  

Seed transmitted power over reflected power ratio has dropped:

We also measured the seed power reflected from the OPO, so that we could compare the ratio of transmitted to reflected seed measured at the time of the squeezer installation in HAM7 in Feb 2022: 61904 (3.9% trans/refl). Today we saw 0.82mW seed transmitted, and 27mW of reflected seed at the bottom of the periscopes (3.03% trans/refl).  This is 78% of the ratio measured at installation.  Because this seems like a large drop, we repeated the measurement twice more, and got 3% each time.  We also checked that the dither lock is locking at the maximum seed transmission.  

Homodyne PD QE check (QE of PDB might be low):

We used an Ophir which was calibrated in 2018 to measure the LO power onto the homodyne PDs, the filter and head are SN 889882 and the controller is SN 889428.  For PDA we saw 0.6mW, for PDB we saw 0.63mW.

Both the PDs are calibrated into mA in the front end, which includes anti-gain of gain(0.25)gain(0.22027), transimpedance of 0.001 (1kOhm), two anti-whitening filters (and cnts2V and mA factors).  For PDA there is a fudge factor in the filter gain, if we divide this out, the readback is that the PDA photocurrent was 0.512mA, and 0.5126mA for PDB (with a drift of 0.5% over the measurement time).  This gives a responsivity of 0.855A/W for PDA and 0.813A/W for PDB.  For QE of 1, the responsivity would be e lambda/(h c) = 0.8582 A/W, so our measurement is 99.6% QE of PDA, and 95% QE for PDB.  (See Vicky measured higher reflection off PDB than PDA in 63893 and Haocuns' measurement in 43452).  

Dhruva, Jenne, Craig, Naoki, Vicky

Summary: ZM4/5 PSAMS at 200V seems to continue improving SQZ-OMC mode-matching, when OMC is held at a spot near the "hot" IFO state. Some fuzziness in results as we saturated the OMC suspension when aligning high ZM4/5 PSAMS. Tentatively, the mode-matching (TEM20) peak seems to improve as we increase PSAMS, but the alignment was not perfect in these tests.

WIth PSAMS at 0V/0V, the beam out of ham7 is bigger; on AS AIR camera, the beam is dimmer and it looks clippy (same exposure), and the power levels on AS QPD's are all very sensitive to clipping (even with DC centering engaged). Maybe at 0/0 we are clipping on the OFI or something en route to the ham6? The 0/0V test is somewhat inconclusive. Also, at higher PSAMS voltages, we started saturating the OMC suspension, so we weren't able to resolve misalignment peaks-- but, the mode-misalignment 20 peak does seem to reduce at higher PSAMS.

Here are our mode-matchings, measured using cursors on ndscope:

• At ZM4/5 PSAMS = 0, 0 V, non-TEM00 ~ 40%,  TEM00~0.19, TEM01~0.127, TEM02~0.004.                 (prob clipping)
• At ZM4/5 PSAMS = 110, 110 V,   non-TEM00 ~ 23%,  TEM00~0.234,  TEM01~0.034,   TEM02~0.034
• At ZM4/5 PSAMS = 150, 150 V,  non-TEM00 ~ 16%,   TEM00~0.27,   TEM01~0.0245, TEM02~0.0245  (omc sus staurated) 
• At ZM4/5 PSAMS = 200, 200 V,  non-TEM00 ~ 15%,   TEM00~0.27,   TEM01~0.034,   TEM02~0.013    (omc sus staurated) 

------ Notes from the process of getting the omc mode scan:

To try and understand the SQZ-OMC matching, yesterday we took OMC mode scans today of the sqz/seed beam, with the OPO dither-locked on sqz laser carrier light. Jenne and Craig set us up for taking OMC mode scans.

• Seed powers: we launched 60mW on SQZT0, got 700uW of OPO IR TRANS when dither-locked, with 2.1mW in OPO IR REFL. 
• IFO had SRM aligned, SR2 misaligned
• AS_A/B_DC_NSUM_OUT_DQ ~ 36.6. ASC-AS_C_NSUM_OUT_DQ ~ 400e-6. Consistent with SRM reflectivity.
• We engaged OMC's AS DC centering - we had enough light on OM1+2 that this just worked.
• Jenne moved OMC alignment from its hot to cold alignment (mostly moving OMC YAW).
• At first, we couldn't find sqz beam on OMC QPD's. So, Jenne aligned the OMC to the IFO beam in single-bounce to get IFO light onto omc qpd's.
  • She recovered this single-bounce IFO situation by locking imc_trans at 5W PSL power, misaligning SRM, then aligning OMC --> IFO single bounce using OM3 + OMC P/Y sliders.
  • The idea here being that with DC centering on OM1/2, we will then align OM3 + OMC to IFO in single bounce so that OM1-2-3+OMC are consistently aligned. Then, we will OM3+OMC outputs to a nice ifo aligned state, and switch the input to the sqz/seed beam. To hold OMC-ASC outputs, Jenne paused OMC_GRD after having it at ASC_QPD_ON earlier. 
  • After going back to sqz beam, even with SR2 misaligned there was too much interference at the AS-port QPD's to align the sqz beam. So, Dhruva unlocked the IMC to totally take away the ifo beam, and we got much quieter AS_A/B QPD signals, and then successfully engaged DC centering on the sqz beam. 
• Craig has good notes for this process in https://git.ligo.org/aligo_commissioning/labutils/-/tree/master/omc_scan
• Basically, after getting OM3+OMC aligned in single-bounce at 5W, we switched back to sqz/seed beam, unlocked IMC, and then engaged DC centering loops for OM1/2.