TITLE: 05/07 Day Shift: 14:30-23:30 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 15mph Gusts, 9mph 5min avg
Primary useism: 0.05 μm/s
Secondary useism: 0.17 μm/s
QUICK SUMMARY: A few issues on arrival. OMC_LOCK isn't able to find a carrier, it actually cant find any peaks at all. SEI_ENV guardian node is in error, which Ibrahim noticed as well. It looks like it can't grab data for some reason. Now that I type this out I'm thinking that there's an issue with Guardian nodes getting data, this would explain why OMC_LOCK sees 0 peaks in its scan, theres an empty peak list if theres an empty data list.
Maintenance can start early, I'll bring the IFO down as soon as I finish some quick investigations.
Workstations updated and rebooted. This was an OS package update. Conda packages were not updated.
TITLE: 05/07 Eve Shift: 23:00-08:00 UTC (16:00-01:00 PST), all times posted in UTC
STATE of H1: Observing at 149Mpc
INCOMING OPERATOR: Oli
SHIFT SUMMARY:
IFO is in NLN and OBSERVING as of 02:14 UTC (5 hr 58 min lock)
When the wind died down, I was able to successfully relock with an initial alignment. SDF Diff Screenshots attached.
Other:
Guardian SEI_ENV node in error keeps happening (3 times now after hitting load). It seems that the issue happens when CONF runs through an 1800s (30 min) checking loop - Jim on leave so didn't contact. There was an E_X saturation a few mins before it happened for the first time though (tenuous link and I do not think it is connected). Screenshot 3 shows the error log.
Had some trouble restarting Nuc5 (was going into it to get channel names). The startup code looks like its running but is taking a while to display anything (still the case after more than 5 mins as shift is ending).
LOG:
Start Time | System | Name | Location | Lazer_Haz | Task | Time End |
---|---|---|---|---|---|---|
01:34 | VAC | Janos | CP3, MX | N | Pump transport | 02:05 |
Correct value for ETMY_L3_LOCK_BIAS is -4.9 77656, ISC_LOCK has now been loaded so we'll need to accept sdf diff on relock today.
IFO is in NLN and OBSERVING as of 2:14 UTC (1hr 21 min lock)
Sheila and Jeff have been looking at the idea of trying to damp some of the triples' bounce and roll modes (mostly the bounce modes), since we seem to be seeing some of them in DARM. The alog thread with notes and candidate IDs for some of the modes starts with alog 77182. While we may not end up wanting to actually damp these modes during Observing (especially if it broadens them), we would at least like to know which modes are associated with a suspension, since other modes could be associated with environmental factors (like HVAC fans).
After chatting with Sheila this morning, I interleaved some attempts at actuating on some of those modes with other work that was going on during this morning's commissioning time. The initial idea was to use a length signal (eg DARM) that we already have access to (via the LSC output matrix) and try to actuate on a triple suspension that is not used for length locking. I ran into some hiccups, but then at least tried something. I think we'll need some model changes in order to try much more.
The challenges:
The successes:
Some thoughts:
TITLE: 05/06 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 24mph Gusts, 16mph 5min avg
Primary useism: 0.04 μm/s
Secondary useism: 0.14 μm/s
QUICK SUMMARY:
We are back to trying to lock, as the wind speed has gone down slightly.
TITLE: 05/06 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Lock Acquistion
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 19mph Gusts, 14mph 5min avg
Primary useism: 0.05 μm/s
Secondary useism: 0.14 μm/s
QUICK SUMMARY:
IFO is in LOCKING and in CHECK_MICH_FRINGES
Been quite the windy day - just got debrief from Tony about status off IFO problems that we've been experiencing.
WP11850 Resync Atomic Clock
Daniel, Fil, Dave:
13:32 PDT: Daniel resynchronized the MSR Atomic Clock to the timing system's 1PPS to clear the timing error.
The procedure was:
Connect a Windows laptop (Daniel's surface) to the RS232 port on the rear of the Symmetricom 4310 Cesium Frequency Standard unit (located in MSR Rack02 U26-27). We used a DB9 null-modem and serial/USB converter cable to connect the RS232 connector to a USB-A port on the laptop.
Daniel ran his monitor code, setting up the serial port for 9600 Baud. We verified the error string as "16,07,00,00,00" which, as before alog70401, means 0x16 Reboot Alert, 0x07 CBT Signal Degradation.
Daniel ran a short 50Ohm coax BNC cable from the SYNC port on the rear of the Atomic Clock to port 8 of the comparitor (the first output 1PPS port). He then ran the resync command which cleared the error.
Power On Hours = 80,205 hours equates to 9 years 2 months.
I reopened FRS28257 for this issue
Attached trends:
50 mins of second trend in the hour before the glitch (8pm Sat night PDT)
30 mins of second trend data after today's resync
2 mins second trend around the time of the glitch (21:16 Sat PDT)
TITLE: 05/06 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 151Mpc
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 29mph Gusts, 19mph 5min avg
Primary useism: 0.08 μm/s
Secondary useism: 0.15 μm/s
QUICK SUMMARY:
After a lockloss while holding ISC_LOCK at LOWNOISE_ASC to fix the TRANISTION_FROM_ETMX issue, we shifted focus to fixing the PRCL1 issue we were having with DRMI, so we were holding in DRMI for a bit. Once that was fixed we went back to holding in LOWNOISE_ASC. after that Commissioning was started.
We were able to get back to NOMINAL_LOW_NOISE at 16:50 UTC and got back into OBSERVING after Commissioners were done with their Commish wish list at 18:36 UTC.
H1 has now been Locked for 3 hours.
Just unlock....
Lockloss 20:00 UTC Most likely to wind gusts.
Lockloss screenshots attached.
While waiting for 50+ MPH winds to blow away, I started an Initial Alignment.
This was going well enough until the SUS SRM watchdogs tripped.
H1 is currently sitting IDLE, due to this wind.
There was again coherence between DARM and SRCL in last night's lock, so I ran a SRCL injection and adjusted the gain of the FF. (FF attached)
I changed the gain from 1.15 to 1.12. 77570 and 77492 are other times this gain has been adjusted in the last few weeks.
The coherence of SRCL to DARM is low at the frequencies that we care most about for this injection (20-50Hz), but the noise in DARM is well above the ambient DARM noise.
Attaching SDF screenshot for both the SRCL and PRCL changes here.
Edit: the SRCL excitation was on from 18:18:57-18:22:00 UTC May 6 2024.
SRCL coupling is indeed non stationary, as shown by the spectrogram attached, where DARM is shown before, during and after the noise injection. During the 3 minutes when the injection was constant, DARM shows non-stationary noise levels at low frequencies.
Computing a BLRMS of DARM between 20 and 50 Hz makes the non-stationary noise level evident. Comaparison of the BLRMS time series with ASC and LSC signals doesn't give much insight.
However, a scatter plot of the BLRMS vs all the ASC and LSC signals gives some hints that the noise is higher when DHARD_P is positive.
Plotting the BLRMS time series together with DHARD_P seems to confirm, although it's not a very strong correlation.
Attached is a screenshot showing a PRCL injection with and without the PRCL offset of -62 in PRCL1.
PRCL offset off: 6/5/2024 17:19:13 UTC
PRCL offset on: 6/5/2024 17:09:19 UTC
The PRCL offset doesn't make much of a difference to the DARM coupling, it may be a little worse with the offset off below 17Hz but a little better above 30 Hz.
I've edited the guardian to no longer have this offset on, because there doesn't seem to be a strong motivation for it and we'd preffer not to have these digital offsets in.
In today's commissoning time, I first did the above measurements of PRCL coupling with and without the offset on, then later readjusted the SRCL gain ( 77648). Below is a comparison of PRCL coherence with DARM before and after these changes (PRCL offset off, seems to have no impact, and SRCL FF retuned). It seems that by retuning the SRCL FF, we have reduced the PRCL coherence with DARM. Also shown is the PRCL coherence with SRCL, which is high at all frequencies.
In 77289 we reduced the PRCL coupling to SRCL and the MICH by phasing POP45 and retuning the LSC input matrix. These didn't improve the PRCL coupling to DARM.
Anamaria, Sheila, Robert
We scanned the biases for three test masses to find the coupling minimum for currents that we injected onto the building ground. The optimal ETMY bias was 115 V in January of 2023, 170 V in Aug. (72308) and 200 V now. With ITMX at 0V, the optimal for ITMY was 60 V in March of 2023 (68053) and -222 V now, The figure shows some of the bias scans.
On the 2nd, Robert Anamaria and I found settings that would set the biases to these values, but the EY value hasn't been correctly applied in the automated relocks since. (77647)
For ETMY, L3_LOCK_BIAS_OFFSET should be -4.9 while the L3_LOCK_BIAS_GAIN is -1 to produce a voltage readback of 200V. I've reset this in the guardian, which I might have done last week with a typo.
This has now been loaded so shoud be at the correct value from 16:00UTC 07 May 2024 77674 .
Anamaria, Robert
We photographed, from a second angle, the beamspot of a stray beam that I noticed last visit (76969 - Fig. 3 ). The photos (Figure 1) confirm that there is indeed a bright stray beam hitting, at a grazing angle, the bellows and other parts of the spool piece between HAM3 and the IMC tube.
I also wanted to measure the power of the stray beam that had been producing a large 48 Hz peak in DARM during early O3, in order to improve my scattering coupling calculations. This is the beam that reflects off of the PR2 scraper baffle and hits the illuminator viewport on HAM3, which we mitigated by inserting a black-glass viewport cover (52184). We were surprised by how bright the beam is, reaching 20 mW on the power meter (see Figure 2), even though we could not fit the whole beam on the meter. We estimate that the beam may reach 60 mW.
Finally, we made movies as we swept the ITMY compensation plate, hoping to see some indication of where the ghost beams are hitting, but did not. We will have to wait until Alena gives us the likely position of the CP ghost beams based on the angles that Anamaria showed us how to measure.
Minhyo, Anamaria,
I've calculated the point at which the tail of the Gaussian laser beam should touch the PR2 scraper baffle to reflect about 60 mW, following Anamaria's idea.
Assuming that the estimated beam size at the PR2 scraper baffle is 7.47 mm, and the total beam power is 3 kW, the beam touches the side of the PR2 scraper baffle's hole at a position 15 mm away (4 sigma) from the center of the beam. I'll include the calculation later on how the beam is actually positioned within the 70 mm aperture of the PR2 scraper baffle.
The original alog referenced above (52184) has photos that show that the aperture of the baffle is visible at the same location as the beam when the interferometer is unlocked, and argues that this means that the beam is hitting the edge of the baffle aperture.
Minhyo
1) Made typo in above comment from mine. The estimated beam radius 7.67 mm -> 7.47 mm (edited on the original comment as well)
2) I'll elaborate the result of calculation in above (15 mm from the center) in below:
Assuming the total power is 3 kW, the percentage of 60 mW power is 0.002%. Since the percentage of normal distribution for 4 sigma is 99.9937%, the partial integration in the upper limit is around 0.0032%.
Using this approximate number, I searched for the exact number to produce 0.002% with a 2D Gaussian beam model with a 3 kW power and 7.47 mm radius. From the beam model, it showed that integration from 4.11 sigma produces a power of around 0.0604 mW, suggesting that the beam is clipped at a point around 14.94 mm (4.11 sigma) from the center of the beam. I have attached a summary figure of my calculation.
Rechecked situation at LLO: https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=70996
TLDR: we see the same, but seems much lower power. Will measure when we get the chance.
Jennie W, Sheila
Today we took OMC scans to help diagnose what is going on with our alignment through the OFI - that is, what is the mode-matching at our the old alignment (as of Monday 22nd) and our new alignment (as of this morning).
Sheila turned off the sidebands before the test and we had the ETMs and the ITMX mis-aligned initially for single bounce configuration.
Old alignment: SR3 M1 YAW OFFSET = -125 microradians
SR3 M1 PIT OFFSET = -437 microradians
SR2 M1 YAW OFFSET = -421 microradians
SR2 M1 PIT OFFSET = -64 microradians
Due to PEM measurements we switched from single bounce off ITMY to single bounce off ITMX.
Locked time = 1 minute from GPS 1398534847
Unlocked time = 1 minute from GPS 1398534984
Scan = 200 s starting at 1398535070 GPS
New alignment: SR3 M1 YAW OFFSET = 120.2 microradians
SR3 M1 PIT OFFSET = 437.9 microradians
SR2 M1 YAW OFFSET = 2061.7 microradians
SR2 M1 PIT OFFSET = -5.5 microradians
Locked time = 1 minute from 1398538330 GPS
Unlocked time = 1 minute from 1398538461 GPS
Scan = 200 s starting at 1398537927 GPS
Dark time with IMC offline and fast shutter closed = 1398538774 GPS
Mode mis-match measurments pending...
The loss through the OMC appears to have increased after whatever happened to the output path on April 22nd.
I use again Sheila's OMC loss calculation code as we previously used in this entry.
Power on refl diode when cavity is off resonance: 29.698 mW
Incident power on OMC breadboard (before QPD pickoff): 30.143 mW
Power on refl diode on resonance: 5.153 mW
Measured effiency (DCPD current/responsivity if QE=1)/ incident power on OMC breadboard: 56.5 %
assumed QE: 100 %
power in transmission (for this QE) 17.029 mW
HOM content infered: 14.415 %
Cavity transmission infered: 66.501 %
predicted efficiency () (R_inputBS * mode_matching * cavity_transmission * QE): 56.494 %
omc efficency for 00 mode (including pick off BS, cavity transmission, and QE): 66.009 %
round trip loss: 3495 (ppm)
Finesse: 335.598
We compare these values to that found from our scans on the 16th April and it seems like the HOM content has increased substantially, the incident power has decreased, and the measured and predicted cavity efficiency has decreased by 3%.
It would be good to cross-check these figures against the other methods of checking the losses, such as DARM offset step and the mode mis-match I still need to calculate from the mode scan taken on the same day.
I forgot to run the same analysis for the locked and unlocked measurements we got at the old (pre April 23rd) alignment of SR2 and SR3.
Power on refl diode when cavity is off resonance: 25.306 mW
Incident power on OMC breadboard (before QPD pickoff): 25.685 mW
Power on refl diode on resonance: 5.658 mW
Measured effiency (DCPD current/responsivity if QE=1)/ incident power on OMC breadboard: 54.1 %
assumed QE: 100 %
power in transmission (for this QE) 13.885 mW
HOM content infered: 19.870 %
Cavity transmission infered: 67.970 %
predicted efficiency () (R_inputBS * mode_matching * cavity_transmission * QE): 54.061 %
omc efficency for 00 mode (including pick off BS, cavity transmission, and QE): 67.467 %
round trip loss: 3289 (ppm)
Finesse: 339.266
Naoki, Vicky, Jennie W
Naoki followed the directions in to set up the SQZ beam OMC scan.
We had a problem with the DC centering loops. After we switched them on they saturated the OM1 and OM2 suspensions.
We got around this by switching each of the 4 degrees of freedom on first - ie. DC3 Y, DC3 P, DC4 Y, DC4 P.
Then we engaged OMC ASC and this seemed to work ok.
When we tried to manually lock the OMC length loop we had problems as when we switched the gain of 1 on it would lose lock, even when on a TM00 mode of the expected height (0.6mA on DCPD_SUM).
Vicky got around this this using a lower gain and not engaging the BOOST filter in the servo filter bank.
Then she had to touch up the alignment in lock with OM3.
locked quiet time 1397329970 GPS 1 min:
OMC-REFL_A_LF_OUT16 = 0.0930255 mW
OMC-DCPD_SUM_OUTPUT = 0.652156 mA
unlocked quiet time 1397330106 GPS 1 minute:
OMC-REFL_A_LF_OUT16 = 1.04825 mW
OMC-DCPD_SUM_OUTPUT = -0.00133668 mA
dark measurement 1397330625 GPS 1 minute:
OMC-REFL_A_LF_OUT16 = -0.0133655 mW
OMC-DCPD_SUM_OUTPUT = -0.00133668 mA
I noticed after I took the dark measurement that OM1 and 2 were staurating again and need to clear history twice on OM1 to remove this.
Reverted OM1 and 2, 3 OMC sliders at 8:33 am (local time) on the 16th April.
Data is saved as REf 3, 4 and 5 in /ligo/home/jennifer.wright/Documents/OMC_scan/2024_04_16_OMC_scan.xml. Where 3 is the scan channel OMC-DCPD_SUM_OUT_DQ on the bottom right plot, 4 is the PZT excitation channel OMC-PZT2_EXC on the bottom left plot, and 5 is the monitor of the actual PZT output voltage OMC-PZT2_MON_DC_OUT_DQ on the top right plot.
Using Sheila's code from this entry and updating the code with the current OMC values for transmission of the mirrors:
Tio = 7670e-6 #according to T1500060 page 116 input and output mirror transmission
R_inBS = 1-7400e-6
The outout of the code gives us the following values for the cavity incident power, efficiency and finesse:
Power on refl diode when cavity is off resonance: 1.062 mW
Incident power on OMC breadboard (before QPD pickoff): 1.078 mW
Power on refl diode on resonance: 0.106 mW
Measured effiency (DCPD current/responsivity if QE=1)/ incident power on OMC breadboard: 70.5 %
assumed QE: 100 %
power in transmission (for this QE) 0.760 mW
HOM content infered: 8.748 %
Cavity transmission infered: 77.827 %
predicted efficiency () (R_inputBS * mode_matching * cavity_transmission * QE): 70.493 %
omc efficency for 00 mode (including pick off BS, cavity transmission, and QE): 77.251 %
round trip loss: 2063 (ppm)
Finesse: 362.923
I need to compare the HOM content measurement with that derived from the mode scan.
Jennie W, Sheila,
We turned off the 9 and 45 MHZ sideband EOMs and unplugged the 118 MHz modulation at the PSL racks. See this alog for how to do this.
We locked the IMC and mis-aligned ITMX.
DC centering loops 3 and 4 were turned on.
Sheila took the OMC lock guardian to PREP OMC scan and turned on the OMC ASC.
We waited for this to converge then turned it off.
We turned input power up to 10W from 2W and then locked the OMC in length manually by using the PZT offset slider to search for a high peak ~ 15mA.
After finding it we turned on the locking with a gain of 24 and the boost and int filters on (we checked the settings we needed in the guardian as we couldn't get the OMC guardian to lock it for us).
Then we turned off the OMC ASC.
We tuned up the OM3 and OMC alignment slightly to maximise the power on OMC-DCPD_SUM_OUTPUT and minimise it on OMC-REFL_A_LF_OUT16.
OM3 was moved down in yaw only from -108 to -117 and OMC was moved down in yaw from 210.5 to 195.5 and down in pitch from 350.4 to 340.4. The final values for the sliders are here.
Quiet time locked after aligning 16:21:03 UTC - 16:24:13 UTC
OMC-REFL_A_LF_OUT16 = 0.652644 mW
OMC-DCPD_SUM_OUTPUT = 15.6162 mA
Quiet time unlocked 16:25:31 UTC -16:27:35 UTC
OMC-REFL_A_LF_OUT16 = 30.106 mW
OMC-DCPD_SUM_OUTPUT = 0.000456763 mA
We took the IMC guardian offline and shuttered the green light going into both arms at the ISC tables, and with ISC_LOCK guardian in idle so it wouldn't keep trying to relock IMC.
Quiet time dark measurement 16:43:38 - 14:46:19 UTC
OMC-REFL_A_LF_OUT16 = -0.0132979 mW
OMC-DCPD_SUM_OUTPUT = -0.00106226 mA
The scan template is saved as /ligo/home/jennifer.wright/Documents/OMC_scan/2024_04_16_OMC_scan.xml
With the references for the time series of the three pertinent channels as:
Ref 0 OMC-DCPD_SUM_OUT_DQ
Ref 1 OMC-PZT2_EXC
Ref 2 OMC-PZT2_MON_DC_OUT_DQ
I ran Sheila's code from this entry, altered with the measured input/output coupler transmission of the current OMC which can be found on Page 116 on LIGO-T1500060.
The output gives this for the cavity parameters:
Power on refl diode when cavity is off resonance: 30.138 mW
Incident power on OMC breadboard (before QPD pickoff): 30.589 mW
Power on refl diode on resonance: 3.879 mW
Measured effiency (DCPD current/responsivity if QE=1)/ incident power on OMC breadboard: 59.5 %
assumed QE: 100 %
power in transmission (for this QE) 18.203 mW
HOM content infered: 9.763 %
Cavity transmission inferred: 66.439 %
predicted efficiency () (R_inputBS * mode_matching * cavity_transmission * QE): 59.509 %
omc efficency for 00 mode (including pick off BS, cavity transmission, and QE): 65.948 %
round trip loss: 3504 (ppm) Finesse: 335.443
I will cross-check the HOM content inferred by analyaing the C02 mode height from a cavity scan.
The mode-matching inferred from the height of the carrier 02 mode vs. the carrier 00 mode from the scan is 0.0983 mode mis-match = 9.83%.
The mode scan fit and the C02/C20 fit are attached.
The code is on labutils /dev branch
The code for the full scan can be ran using:
python OMCscan_nosidebands9.py 1397320410 80 "Cold OM2, 10W PSL, pre-output loss" "single bounce" --verbose -m -o 2
The code for the C02 fitting can be done using:
fit_two_peaks_no_sidebands9.py
Where the blue trace is the data, the orange is the fit, and the purple is the function plotted with the inital guesses for the fit parameters as a cross-check.