WP 11805
ECR E2400083
Lengths for possible SPI Pick-off fiber. Part of ECR E2400083.
PSL Enclosure to PSL-R2 - 50ft
PSL-R2 to SUS-R2 - 100ft
SUS-R2 to Top of HAM3 (flange D7/D8) - 25ft
SUS-R2 to HAM3 (flange D5) - 20ft
Put a small excitation on H1:SUS-ITMY_L3_LOCK_BIAS_EXC to check why ITM in-lock charge measurements not working. This excitation worked fine when I used both awggui and awg via the interactive guardian (plot).
Unsure why it's hasn't worked for ITMs the last two weeks: 76895, I restarted the guardian before I started so maybe that was needed even though the ESD_EXC_ITMY guardian clears all test points before starting.
The Hammer Training Facility informed us that they will be doing demolitions this week. We have seen these explosions in the past (alog52525), so we expect to see them onsite again. This facility is located to the Southeast of the site about 8-9miles away.
Eric, Naoki, Vicky, Jennie W, Sheila
We did SQZ OMC mode scan with cold OM2. The PSAMS is 175/100 (strain voltage 8.9/-0.69). The attached figure shows the result (ref 34). The SQZ OMC mode matching is 0.64/(0.64+2*0.03)~91.4%.
We followed the instruction in 74892. Here are some notes.
PSAMS 175/100, cold OM2
DARK
I used my code to fit the scan and C02 peak for this scan. As we saw with the PSL beam the new OMC means we cannot resolve these two peaks.
But if I assume one is buried in the noise and do the fit anyway we get (0.027 - 0.0038)/(0.027 + 0.64 - 0.0038) = 3.5% mode-mismatch for the squeezed beam matching to the OMC, with a fitted HWHM of 0.33 MHz.
NB: The factor 0.0038 mA is what I had to add to the scan data to shift the baseline to be above zero otherwise the fitting doesn't work well.
If I just use the measured height of C02 from the full scan (which is like assuming both C02 and C20 are overlapped) the mode-mismatch would be (0.029 - 0.0038)/(0.029 + 0.64 - 0.0038) = 3.8 %.
The OMC (001 is the current) parameters are given in this alog by Matt Todd, this gives a value for the half-width at half-maximum of 0.31MHz which matches our fitted one fairly closely.
The C02 peak graph (second image) has the OMC scan data in blue, fit in red, and initial guesses for the fit in purple.
Looking at this SQZ-OMC mode scan (data, mode scan), and running the same scripts as before (e.g. LHO:70866), this loss estimate based on OMC visibility using the squeezer beam doesn't really make sense. Hopefully PSL scans will make more sense. May be worth re-taking this squeezer measurement sometime.
Mode-matching and visibility make sense: Single-bounce SQZ-OMC mode mismatch ~ 4% based on TEM02/20 is consistent with Jennie's peak fitting, HOM content ~ 9-12%, and OMC locked/unlocked visibility = 1-locked/unlocked ~ 90%.
Loss estimate does not make sense: the inferred OMC transmission is ~72%, and if we ignore mode mismatch (ie assume 100% matching) this corresponds to an OMC transmission of 81%. But ~20% omc loss is ruled out by observed squeezing levels.
5.4 dB SQZ corresponds to a total loss of 20-25%, see params below including 12.3% expected sqz losses. This limits OMC losses < 10-15%, if assuming no mode-mismtch. With mode-mismatch, squeezing suggests OMC losses << 10%. This is not saying much, except this measurement is off.
So squeezing rules out the ~20% omc losses inferred from this sqz-omc visibility measurement. I'm not sure what is exactly is wrong, but in the mode scan, there was considerable TEM01/10 misalignment despite running OMC ASC + manual alignment. Unsure if alignment is the issue, or maybe something wasn't right with the squeezer beam, such that alignment couldn't improve (worth checking the beam round-ness on sqzt7?).
Script output below (code in git). Running this and Sheila's script in LHO:70866, I get the same output. So, the script seems OK, but something else is wrong with this measurement.
--------------- er16 sqz ------------------ processing measurement for er16 sqz P_Refl_on_res*1e3 = 0.12831 mA P_Refl_off_res*1e3 = 1.00626 mA Trans_A*1e3 = 0.62987 mA (I assume OMC-DCPD_SUM_OUTPUT is calibrated into mA with the new OMC, I did not check this calibration.) removed trans blocked of -0.00332 mA Power on refl diode when cavity is off-resonance: 1.006 mW Power on refl diode when cavity is on-resonance: 0.128 mW Trans power when cavity is on-resonance: 0.734 mW Incident power on OMC breadboard (before QPD pickoff): 1.026 mW Measured efficiency (DCPD current/responsivity if QE=1)/ incident power on OMC breadboard: 71.546 % Using 4.0% mode-mismatch from Jennie peak fitting, visibiilty_00*100 = 90.885% assumed QE: 100 % power in transmission (for this QE) 0.734 mW HOM content infered (like mode matching): 11.964 % Cavity transmission infered: 82.057 % predicted efficiency () (R_inputBS * mode_matching * cavity_transmission * QE): 71.546 % omc efficency for 00 mode (incl R_inBS * cavity_transmission * QE, no mm): 81.270 % round trip loss: 1606 (ppm) Finesse: 372.613
Lights off, paging and WAP stayed off. Some unused extension cords unplugged. Turned off SQZ laptop and monitor.
Faro is still plugged in (expect it is staying warmed up to be used next week). Still some PEM equpement plugged in, photo. HAM3 dust monitor has a fairly long extension cable, photo.
All else looked good, followed T1500386
We ran the functionality test on the main turbopumps in MY and EY. The scroll pump is started to take pressure down to low 10^-02 Torr, at which time the turbo pump is started, the system reaches low 10^-08 Torr after a few minutes, then the turbo pump system is left ON for about 1 hour, after the hour the system goes through a shut down sequence.
MY Turbo:
Bearing Life:100%
Turbo Hours: 212
Scroll Pump Hours: 78
EY Turbo:
Bearing Life:100%
Turbo Hours: 1280
Scroll Pump Hours: 76
No issues encountered for either turbopump
Dust monitor pumps are running smoothly. The corner station dust monitor pump has been rebuilt and is now up and running.
Tue Apr 09 10:09:41 2024 INFO: Fill completed in 9min 37secs
Gerardo confirmed a good fill curbside
The CLF REFL Transimpedance gain seems wrong at 0.25A/W and R=47500, reverted it to 0.77A/W and R=10000, which reaults in the same calibration as the fast channel. This was changed on 4/27/2023 the first day of O4a. no alog.
Now that the corner station pump is back up and running (alog pending) I started getting dust alarms. The alarm values somehow got reset back to our chamber open values, even though Ryan changed them Feb 23rd (alog75944). End stations were OK, so I left them as is.
For DMs 5,6,10 for the 0.3um and 0.5um, changed 70->7000 and 100->10000 respecivetly.
Measured the sensitivity of the new CLF VCO:
Offset at Tune Input | Tune readback | Frequency (MHz) | Difference (kHz) |
---|---|---|---|
-1V | 3.332V | 202.690924 | 436.1 |
0V | 4.067V | 203.127060 | 0 |
+1V | 4.800V | 203.542136 | 415.1 |
which results in ~425kHz/V.
Today I adjusted the PSL pump diode operating currents to attempt to improve PMC Trans while maintaining output power. PMC Trans has been dropping and PMC Refl increasing, and alignment tweaks have not been yielding much improvement; suspect the cause is mode matching changes due to the natural decay of the pump laser diodes. With the ISS OFF I tried several different combinations, but the best was found by asymmetrically pumping both amplifiers slightly; the attachment shows the various steps and how they changed PMC Refl and Trans. I ended up with the following current setpoints (actual current is slightly lower, as seen in the attached trends): PS1 at 9.1A, PS2 at 8.9A, PS3 at 8.9A, and PS4 at 8.8A (PS1 and PS2 supply the Amp1 pump diodes, PS3 and PS4 supply the Amp2 pump diodes). When I re-engaged the ISS I had to adjust the RefSignal from -1.94V to -1.95V to account for the slightly increased power transmitted by the PMC. PMC Trans is currently ~109.0 W and PMC Refl is currently ~16.8 W. Will continue to monitor this.
This closes WP 11806.
04/07/2024 11:32:46UTC A dolphin crash (77040) caused the detector to unlock, tripped HAM1 Hepi, and caused a bunch of front ends to trip. Called Dave and Erik, who were able to fix everything
12:22 ISI ITMX Stage 2 watchdog tripped
I took IMC_LOCK to DOWN, SQZ_MANAGER to DOWN, and manualed ISC_LOCK to IDLE
Before the model restarts that were required, I put the corresponding suspensions into SAFE and the HAMs and BSCs into ISI_DAMPED_HEPI_OFFLINE
Once the CDS issue was sorted out, I untripped all the SUS WDs that had tripped and took the chambers back to ISOLATED/FULLY ISOLATED
13:43 Started relocking, went to GREEN_ARMS_MANUAL before starting an initial alignment
- Having issues with the ALS XARM beatnote
- Tried toggling No Force/Force - didn't work
- Not due to low beatnote
- Reset all optics except sqz to a time when we were in READY two locks ago (1396640117) - worked
14:31 INITAL_ALIGNMENT started
TITLE: 04/09 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Aligning
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 12mph Gusts, 9mph 5min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.21 μm/s
QUICK SUMMARY: Oli has been working on realigning after the dolphin crash. Just now trying to finish off and SRC alignment before moving to maintenance mode.
Workstations were updated and rebooted. This was an update to OS packages. Conda packages were not updated.
Oli, Erik, Dave:
Around 04:30 this morning a ADC channel hop on h1iopomc0 caused all of the omc0 models to stop running, and also caused a corner station Dolphin glitch which DACKILLED h1susb123, h1sush34, h1sush56 and h1lsc0.
h1omc0 dmesg:
[Tue Apr 9 04:34:05 2024] rts_cpu_isolator: LIGO code is done, calling regular shutdown code
[Tue Apr 9 04:34:05 2024] h1iopomc0: ERROR - A channel hop error has been detected, waiting for an exit signal.
[Tue Apr 9 04:34:05 2024] h1omcpi: ERROR - An ADC timeout error has been detected, waiting for an exit signal.
[Tue Apr 9 04:34:05 2024] h1omc: ERROR - An ADC timeout error has been detected, waiting for an exit signal.
Initially I thought this was an IO Chassis issue, so we power cycled h1omc0 rather than a restart all of its models (my confusion was because this front end only has one Adnaco, and is running the low-noise ADC). This brought h1omc0 back up and running.
We restarted the models on h1lsc0, which cleared the DACKILL.
Oli put the SUS and SEI for BSC1,2,3 and HAM3,4,5,6 into safe, I SWWD bypassed the SEI IOPs and we restarted the models on h1susb123, h1sush34, h1sush56. All came back with no problems.
I cleared the SWWDs, did a DIAG_RESET and cleared the DAQ CRCs.
Handing over to Oli for IFO recovery.
CDS Overview after DIAG_RESET run on all front ends:
Time of OMC crash:
04:32:45 PDT
11:32:45 UTC
1396697583 GPS
We've been locked for 6:50, range is lower tonight
A 6.0 from Indonesia rolled through around 00:38 UTC
SQZer lost lock and dropped us from observing at 04:22, will return once it relocks. Back into observing at 04:26UTC
This lockloss was due to the OPO PZT running out of range @40V, plot. There's already a checker in SQZ_MANGER to relock when IFOs unlocked and OPO PZT1 is below 50V but it was at 70V when the IFO locked.
This could be a bad readback, or real, we are not sure. The signal should be 23dB, but the readback is showing 16.8dB on NDSCOPE and has been trending down for a while, it is throwing an error flag in beckhoff. This signal is located in ISC-R1 slot U16 on the left side. The LO signal is 9MHz and is fed through a delay line chassis, there are also baluns, cabling, etc... We were not able to determine the source of the readback error before noon, so this will have to wait until a maintenance window.
M. Pirello, F. Mera, D. Sigg
Measured RF power at the
The analog readback of the power detector was 5.89V at the front panel. This has been confirmed to be the same as the slow controls readback, which corresponds to 23.3dBm.
Seems like disconnecting and connecting the LO cable" fixed" the problem. Flaky cable and/or connector?
Paused TCS_ITM_CO2_PWR guardians so that when the IFO unlocks the CO2s will stay on so we can take absorption measurements of the ITMs using HWS (need ITMs and SR2 to stay aligned for 1 hour after lockloss).
Un-paused at 16:01UTC, CO2s are back to 0W output.
Last done in 71400.
Using Dan's /ligo/gitcommon/labutils/hws_absorption_fit/april2024/fit_absprtion_v2.py with lockloss time 1396105132, edited P_y and P_x values to adjust the fit and old and new origin values (ours are correct, checked in 76385).
This is an interesting data set as you can see when the CO2's were turned back to 0W after an hour, ndscope attached.
The IFO had only been at full power for ~1hour, this might explain the lower values than previously measured. Plot of fits attached. Fit of ITMY isn't very good. We could try using Cao's clean spherical power channels (single pass) or his 66155 fitting code. LLO also uses a different method LLO69930.
ITMX: 155mW absorbed = 430ppb (155mW / 361kW)
ITMY: 120mW absorbed = 330ppb (120mW / 361kW)
April 2022 (62468, 62782) | Nov 2022 (66036) | April 2023 (71400) | April 2024 | |
ITMX | 430ppb | 490ppb | 475ppb | 430ppb |
ITMY | 370ppb | 385ppb | 375ppb | 330ppb |
J. Kissel As we continue to investigate both ADC noise (both broadband, in-general behavior) as well as down-converted aliasing noise in the new fast 524 kHz OMC DCPD signal chain, I needed to wrap my head around all the available channels in order to begin thinking about how to compare / take advantage of the differences between the channels. I don't understand anything until I diagram it, so here's my diagram of the existing OMC DCPD signal chain as I understand it, hoping it helps others. As mentioned in each of the previous aLOGs where I've started the investigation (LHO:67552, LHO:67530, LHO:67465, LHO:67297, LHO:67439), studies of the 524 kHz portion of the system are severely limited in that (a) no 524 kHz channel stored in the frames, (b) one can only look at 3 test points at a time, (c) we don't have any analog measure of the noise between 524 kHz and 102.4 kHz (the upper limit of the SR785) to compare against But, we'll do what we can! Hopefully this visual aide will help understand future studies. For example, because we *don't* have any digital anti-aliasing filters in the OMC-PI SIG filter bank, we can compare these test point channels, - H1:OMC-DCPD_A0_OUT (524 kHz, w/ digital anti-aliasing) - H1:OMC-PI_DOWNCONV_SIG_OUT (524 kHz, w/o digital anti-aliasing) - H1:OMC-PI_DPCD_64KHZ_AHF (65 kHz, w/o digital anti-aliasing) - H1:OMC-DCPD_A_IN1 (16 kHz, w/ digital anti-aliasing) to explore the effectiveness of the digital anti-aliasing filters to better understand the aliasing that Evan Hall found in LHO:67328. Note -- and this is something that I'm still learning (via conversations with Erik von Ries and Daniel Sigg and their aLOGs, including but not limited to LHO:67587, LHO:67560, LHO:67291) -- the h1iopomc0 model actually runs at 65 kHz (really, 2^16 kHz). In order to achieve a pseudo-524 kHz data stream, there's a for loop within the h1iopomc0 model that's able to complete 8 iterations (thus 2^16 kHz * 8 = 2^19 kHz = 524 kHz) during any given 65 kHz clock cycle.
Sorry team. There's a typo in the 65 kHz version of the DCPD channel in the PI model in both the above list, as well as in the diagram. The channel list to accompany the diagram should be - H1:OMC-DCPD_A0_OUT (524 kHz, w/ digital anti-aliasing) [[NOT STORED IN THE FRAMES, ONLY LIVE AVAILABLE]] - H1:OMC-PI_DOWNCONV_SIG_OUT (524 kHz, w/o digital anti-aliasing [[NOT STORED IN THE FRAMES, ONLY LIVE AVAILABLE]] - H1:OMC-PI_DCPD_64KHZ_AHF (65 kHz, w/o digital anti-aliasing) [[STORED IN FRAMES at 65 kHz as H1:OMC-PI_DCPD_64KHZ_AHF_DQ]] - H1:OMC-DCPD_A_IN1 (16 kHz, w/ digital anti-aliasing) [[STORED IN FRAMES at 16 kHz as H1:OMC-DCPD_A_OUT_DQ]] Careful here: In O3, H1:OMC-DCPD_A_IN1 was NOT equivalent to H1:OMC-DCPD_A_OUT_DQ, since H1:OMC-DCPD_A_IN1 *used* to be the "raw" (down-sampled, and digital AA filtered) ADC 16 kHz channel, and then the DCPD_A bank applied all of the the calibration and frequency response compensation. Now, as of O4, with the 524 kHz system, that's done in the DCPD_A0 bank, and the DCPD_A bank is an "empty" gain of 1.0 "passthrough," so DCPD_A_IN1 is equal to DCPD_A_OUT.
Further, a reminder that we've installed a "plug" that shorts the ADC inputs of channels 17 through 20 of this new 524 kHz system, so looking at the channels might also be interesting if we're looking for noise that might be present on the ADC channels alone (i.e. without any signals going into it). See LHO:67465 for details, but in short, you want to look at the (live, not stored in the frames) 524 kHz channels, - H1:IOP-OMC0_MADC0_EPICS_CH17 - H1:IOP-OMC0_MADC0_EPICS_CH18 - H1:IOP-OMC0_MADC0_EPICS_CH19 - H1:IOP-OMC0_MADC0_EPICS_CH20 for a "shorted" version of the OMC DCPD ADC card channels. This would be useful to, say, investigate how / why the DuoTone signal shows up in the DCPDs (see LHO:77579), and to compare and contrast against the L1 DCPDs which also see it (see LHO:70961), but they've not yet segregated their OMC ADC card, and (I think) have a different, older version of the Timing Interface card.