After the early evening winds dropped below 30mph, returned to locking and H1 made it back ton NLN. Had to turn on Squeezing and then ran requested SQZ states (Scan_Alignment_FDS & Scan_SQZAng). Naoki also looked at alignment for the squeezer to address squeezer noise as well.
Finally returned to Observing with H1 and it's different/new SR2/SR3 pointing (from today's commissioning work earlier). Range is hovering around 145Mpc.
FranciscoL, [Remote: RickS]
After one week of moving the inner beam to the center of the Rx (alog 77967), on May 28, we moved the beam down. This completes a cycle in which we characterize the XY comparison value to both directions of the pcal beam movement - one side right, one side down.
Attachment 'BothBeamsBefore' shows the beams before making any changes. Attachment 'AlignedTarget' shows the alignment with the beam height gauge. The pdf 'EndStationLog.pdf' lists the voltage values after each significant step of procedure T2400163. The steps represent writing down a voltage value after a particular change of the system. Some steps were recorded multiple times after minor changes.
The voltage ranged by ± 0.01 V during the measurement, mostly noticed when the target is placed on the integrating shpere. We might need to look closer at the seismic isolation configuration to reduce the noise during this - and potentially also end station - measurement procedure.
The 'Initial' measurement is *equal* to the last voltage measurement from the previous movement, done on May 21 (alog 77967). The initial and final voltage measuremed during todays procedure did not change.
With the movement made today, we expect that the X/Y comparison will change by +21.15 HOPs.
Today Dripta and I went to EY and did what would have previously call a standard ES measurement with PS4.
And We also employed the new End Station procedure.
Details and analysis ccoming in a comment to this alog.
A PCAL ENDY Station Measurement was done on May, the PCAL team (Dripta B. & Tony S.) went to ENDY with Working Standard Hanford aka WSH(PS4) and took two End station measurements to verify that the results were consistent with each other. One with our previous version of T1500062-V16 procedure and another with T1500062-V17.
The ENDY Station Measurements was carried out mostly according to the procedures outlined in Document LIGO-T1500062-v16 & v17, Pcal End Station Power Sensor Responsivity Ratio Measurements: Procedures and Log.
Measurement Log
First thing we did was take a picture of the beam spot before anything is touched!
Martel:
Martel Voltage source applies voltage into the PCAL Chassis's Input 1 channel. We record the GPStimes that a -4.000V, -2.000V and a 0.000V voltage was applied to the Channel. This can be seen in Martel_Voltage_Test.png . We also did a measurement of the Martel's voltages in the PCAL lab to calculate the ADC conversion factor, which is included on the above document.
Plots while the Working Standard(PS4) is in the Transmitter Module during Inner beam being blocked, then the outer beam being block, followed by the background measurment: WS_at_TX.png.
The Inner, outer, and background measurement while WS in the Receiver Module: WS_at_RX.png.
The Inner, outer, and background measurement while RX Sphere is in the RX enclosure, which is our nominal set up without the WS in the beam path at all.: TX_RX.png.
-----------------------------------------------------------------------------------------------------------------------------------------------
The New Document has a different order of measurements that are taken and are taken in a different way.
We placed the Working Standard (PS4) in the path of the INNER Beam at the TX module.
Then the Working Standard (PS4) in the path of the OUTER Beam at the TX module.
A background measurement.
Then we take the Working Standard and put it in the RX module to get the INNER Beam.
Then the OUTTER Beam in the RX Module.
And a Background.
This is where things get different....
We remove the beam block and give the Working Standard Both Inner and Outer Beams at the SAME TIME while it's at the RX module.
We also put the RX sphere back to the RX module and put both beams on it at the same time. Like nominal opperation when the PCAL lines are turned off.
Then we take a background.
This was repeated ~10 mins later because we wanted to see if there is any time dependent variations.
The last picture is of the Beam spots after we had finished the measurement.
Old procedure measurement results : "rhoR_prime": 10565.2
New Procedure Measurement: rhoR_prime : 10571.1. This 5 hop difference is well within our uncertainty .
second New Procedure rhoR_prime 10574.3, was off by less than 3hops ,well within uncertainty.
Preliminary analysis suggests that discrepancy in rhoRprime calculated via two methods is allowed within the uncertainty.
All of this data and Analysis has been commited to the SVN or GIT:
https://svn.ligo.caltech.edu/svn/aligocalibration/trunk/Projects/PhotonCalibrator/measurements/LHO_ENDY/
Obligitory BackFront PS4/PS5 Responsivity Ratio:
PCAL Lab Responsivity Ratio Measurement:
A WSH/GS (PS4/PS5)BF Responsivity Ratio measurement was ran, analyzed, and pushed to the SVN.
PS4PS5_alphatrends.pdf to show that the recent changes to the lab have not impacted the Lab measurements
This adventure has been brought to you by Dripta B. & Tony S.
TITLE: 05/28 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 24mph Gusts, 16mph 5min avg
Primary useism: 0.06 μm/s
Secondary useism: 0.12 μm/s
QUICK SUMMARY:
The site is currently being hammered by high winds gusts have recently started approaching 40mph (H1 just had a lockloss during these high winds...and green arms have been having troubles, so I am taking H1 to IDLE and Observatory Mode to WINDY on an hr by hr basis....hoping winds cooperate after sundown.
When H1 is able to return to NLN, Camilla requested for SQZ that scan_alignment_fds & scan_sqzang be run.
Terry, Kar Meng
The second SHG seems to have the appropriate finesse (~60) at 1064 nm. Next steps remove high reflector from temporary mount and place it in the SHG housing, then recover modes then look for green light.
TITLE: 05/28 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Corey
SHIFT SUMMARY:
IFO is in LOCKING at LOCKING_ARMS_GREEN.
We acquired NLN earlier but lost lock while some last min SQZ maintenance was being done. We lost lock from LOWNOISE_COIL_DRIVERS at 23:23 UTC and the wind is really picking up now (40mph gusts).
LOG:
Start Time | System | Name | Location | Lazer_Haz | Task | Time End |
---|---|---|---|---|---|---|
14:45 | FAC | Ken | LVEA | N | Conduit work | 19:01 |
15:00 | FAC | Kim | EX | N | Tech cleaning | 16:08 |
15:03 | VAC | Jordan | MX, EX | N | Turbopump Tests | 17:16 |
15:10 | PCAL | Tony, Dripta | EY | Y | Transitioning to Laser Hazard, PCAL Calibration | 18:08 |
15:11 | SYS | Jeff | LVEA | Y | OMC Electronics Characterization | 17:30 |
15:12 | SAF | LVEA | LVEA | YES | LVEA IS IN LASER HAZARD | 18:04 |
15:19 | IAS | Tyler | LVEA | Y | Faro Work | 19:10 |
15:24 | TCS | TJ | LVEA | Y | Realigning HWS Corner System | 16:36 |
15:26 | IAS | Ryan C | LVEA | Y | Faro Work | 19:12 |
15:31 | VAC | Travis | EY | Y | Install decoupled cooling lines on EY Turbo Station | 19:00 |
15:38 | PSL | Jason, Ryan S | PSL Enclosure | Y | Investigating PSL slow increase in PMC reflected power | 18:04 |
15:41 | TCS | Camilla | LVEA | Y | Realigning HWS Corner System | 16:35 |
15:46 | ISC | Richard, Fil | EX, EY (not VEAs) | N | Temp unplug of IRIG-B Signal from ADC | 16:18 |
15:54 | FAC | Chris | LVEA | Y | Chat with Tyler | 16:11 |
15:54 | FAC | Karen | EY | Y | Technical Cleaning | 15:54 |
15:58 | ARCH | Archeologist | MY Chiller Yard | N | APE Check (Area of Potential Effect) | 17:15 |
15:58 | VAC | Gerardo | LVEA | Y | Pulling Cable | 19:07 |
16:06 | PCAL | Francisco | EY | Y | Grabbing Laser Gogges | 16:33 |
16:07 | PEM | Robert | LVEA | Y | Comissioning test setup | 18:40 |
16:12 | FAC | Chris, Eric | Mechanical Rm | N | Replacing Fan Bearing | 19:12 |
16:23 | EE | Fil | LVEA, CER | N | IO Chassis Inspection, Helping VAC | 19:15 |
16:33 | SEI | Jim | LVEA | Y | Electronics work by HAM7 | 19:05 |
16:34 | PCAL | Francisco | EX | Y | PCAL Spot Move | 18:26 |
16:42 | FAC | Karen, Kim | FCES | N | Tech Cleaning | 17:11 |
16:50 | Terry | Optics Lab | N | Optics Lab Work | 18:57 | |
17:16 | ARCH | Archeologist, Richard | EY Beam Tube | N | APE | 17:57 |
17:17 | VAC | Jordan | LVEA | Y | Helping Gerardo pull cables | 19:07 |
17:31 | SYS | Jeff, Preet | LVEA | N | OMC Electronics Characterization Pt 2 | 18:59 |
17:41 | VAC | Janos, Isaiah | LVEA | N | Pulling Cables | 19:07 |
18:04 | IAS | Jason | LVEA | N | Faro Work | 19:12 |
18:21 | PCAL | Tony | PCAL Lab | Local | Responsivity ratio measurement | 18:49 |
18:36 | EE | Marc | LVEA | N | Unplugging (after talking to Fil in LVEA) | 18:52 |
19:13 | OPS | Ryan C | LVEA | N | LVEA Sweep | 19:24 |
20:04 | VAC | Janos, Isaiah | MY | N | Tour | 21:04 |
20:23 | PCAL | Tony | PCAL Lab | N | Measurements | 22:43 |
20:52 | CAL | Terry | Optics lab | Y | SQZ work | 23:15 |
I made two minor changes that I tested out during relocking today.
LOCKING_ARMS_GREEN state will not run increase flashes if the SEI state is not nominal in the respective arm. This is to stop increase flashes aligning to while an ISI is tripped and aligning to a bad spot. It will notify "Arm SEI not nominal, no I.F. until resolved", but I couldn't get it to stay up for long before other notifications would get in the way. Regardless, it wont run I.F. and will work for unattended times.
In ALS_DIFF the find IR used to step the offset and then do an instantaneous check to see if there was any resonance with a low threshold. We've gotten unlucky a few times where it dipped just below the threshold during the check. To remove luck from this, I have it now grab data every step and look at the max. The downside to this is that if there is an nds issue, it will fail. I also increased the fine tune IR step size from 3 ->5 and it seemed to work well.
Sheila, Camilla, Jenne, Naoki
While Ibrahim was doing initial alignment during maintence today, I moved SR3 (using sliders) and SR2 using the osem, to the positions in the second column of 77719 (-P move of SR3, May 7 10:39 pacific).
Alena has been working with the zeemax model of what happened when our OFI was damaged, and she believes that this location is more centered in the OFI, and this data may be useful to her modeling. We haven't recovered the range or all of the optical gain that we thought was possible before the OFI was damaged (our OMC alignment wasn't optimized when this happened), so we are hoping that a different spot may help.
When we relocked after this the range was low (~145 Mpc), the attached screenshot shows that we have more LSC coherence now. We should be able to adjust LSC feedforward during tomorow's commissioning time to address that.
I have been testing a high voltage version of the cps in the staging building for several months now. These new sensors are supposed to have something like 4x lower noise than the cps we currently use, cps noise limits table motion between about .5-10 hz. This morning I tried to test them on the HAM7 ISI this morning. The test just required disconnecting the existing satellite chassis at the chamber and connecting a new set of in air electronics outside the chamber.
I did a couple quick transfer functions to check the sensor responses made sense, then turned on the isolation loops. Loops were stable, no problems there, but I didn't get good performance data. There were a number of people working near the chamber, so it wasn't very quiet. It also didn't seem like the HV cps noise floors were as low as I've been able to get on my test stand in the staging building.
Attached plot compares individual some cps noise floors, red and green are regular sensors from some time in the middle of the night, purple and black are the lowest noise high voltage sensors from my test this morning. Unfortunately, the other 4 HV cps were the same noise or higher than the regular sensors. I didn't have a lot of time to try to poke at the new sensors. I'll try again next week, it would help if I can have it quiet around the chamber it would help, but that doesn't affect the 100hz noise.
J. Kissel EDIT :: False Alarm -- see comment below! Since I'm at the "what does it all mean?" stage of madness with the OMC DCPD Transimpedance Amplifier (TIA), I decided to make it worse -- I remeasured the original transfer function that triggered me worrying about the TIA response in after the OMC swap (see LHO:75986). I did this to try to corroborate whether there is a change in the DCPDA response above 1 kHz as mentioned in LHO:78090. This transfer function is the remote, DAC-driven measurement of the whole DCPD sensing chain -- the transimpedance amplifier, the whitening chassis, and the front-end compensation for the frequency response of those -- this has been described most recently in LHO:71225. I *don't* see a difference above 1 kHz, but I *do* see more difference in response below 25 Hz than I had in 2024-Feb-26. See the attached transfer functions of the DCPDA chain and the DCPDB chain. Black is pre-OMC swap, 2023-Jul-11. Brown is post-OMC swap, 2024-Feb-26. Red is today, also-post OMC swap, 2024-May-28. All measurements use the S2300003 whitening chassis, and the compensation from the 2023-Mar era compensation we've been using throughout O4. The only "oh, well it could just be" that I can think of immediately is that the DCPDs had been powered down from 10:10a to 11:30a PDT today to characterize the measurement setup in analog (see LHO:78090), and these were measured "only" 20 minutes after being powered back on at 11:50a. So -- we'll have to take the measurement again at the next opportunity -- such that the TIA electronics have what we think it the appropriate amount of time to thermalize -- a few hours. Just maddening. Data lives in /ligo/svncommon/CalSVN/aligocalibration/trunk/Common/Electronics/H1/SensingFunction/OMCA/Data/ 20240528_H1_TIAxWC_OMCA_S2100832_S2300003_DCPDA_RemoteTestChainEXC.xml 20240528_H1_TIAxWC_OMCA_S2100832_S2300003_DCPDB_RemoteTestChainEXC.xml
False alarm! It appears indeed that I had inadvertently captured a thermal transient of the transimpedance amplifiers -- since it had only been 20 minutes since I'd turned on the power to the preamps. See LHO:78112, where I took this same measurement again, and the response restored to the same post-2024-OMC-swap-vent response.
J. Oberling, R. Short
Our PMC Refl signal has been slowly increasing over the last several months; by extension this means that PMC Trans and the amount of power available to the IFO has been decreasing. Ryan and I went into the PSL enclosure to take a look at things.
We began by using an IR viewer to look at the PSL optics. All looked as expected except for M11, which was a bit brighter than we both recall; this is the 1st of the two turning mirrors that steer the beam into the PMC. We noted to take a close look at this optic once we had things turned off. We next took several power measurements around the PMC, all done with the ISS OFF; with the ISS OFF the power moves around a little bit more, so I've included the min and the max readings at each location:
Things here match our PD calibrations OK. One thing we noticed, the amount of ISS diffracted power was a little low for the amount of variation we were seeing in the output of Amp2; we therefore adjusted the ISS offset a little to bring that bank back up a bit, to ensure we have enough power available to counter the swings in Amp2 output. We finished here with an offset of 4.7, and 4.2W in the ISS diffracted beam (again, this was with the ISS OFF). The ISS now defaults to ~3.0% diffracted power when it is OFF (this change was accepted in both SAFE and Observe SDF).
This done we moved on to inspecting optics with our green flashlight. With the PMC unlocked and the PSL external shutter closed, we looked at all of the optics between the external shutter and the PMC. Sure enough, all optics looked good except for M11 (see first picture). 8 in situ, very careful drag wipes later the optic looked much better, and better yet no signs of damage (see 2nd picture). Still some small dots on it that I couldn't remove, my guess is these are small coating defects that the green flashlight is really highlighting. We then opened the shutter and viewed the mirror through the IR viewer, and while it was still a little bright it did look much better. The PMC relocked without issue, but PMC Refl was higher than when we started (likely due to the PSL environmental controls being on and slight alignment shift during drag wiping M11).
Last, we checked centering on the PMC locking PD and the PD that reads PMC Refl. These PDs were well centered, with no improvement made when we tried to adjust the alignment onto the PD. This tells me that we have not seen an alignment shift between Amp2 and the PMC, which tracks with the fact we have acheived almost zero improvement to PMC Trans/Refl by tweaking beam alignment. Since we already had a mutlimeter set up, we took a visibility measurement for the PMC:
The visibility measurement looks good, really good, and does not match what we see with PMC throughput. Using our power measurements from earlier, we're only transmitting ~83.7% of the incident light through the PMC, nowhere close to what our visibility measurement suggests. This reminds me of the old loss issues that plagued the original glued aLIGO PMCs at LLO, and spurred the development of the all-bolted PMCs we're using now at both sites. Could our issue be loss build-up in the PMC? This suggests that is a likely possibility.
At this point we left the enclosure to consider next steps. We do have a spare all-bolted PMC that we could swap in and see how it performs. This is, theoretically, a quick process, as the all-bolted PMCs have magnetic ball mounts that help preserve PMC alignment upon removal (we tested this a little when we installed this PMC in April 2018, and it seemed to work well). For now, the PMC Refl signal is still higher than when we went into the enclosure, by almost 3W. This isn't entirely surprising, as I did clean mirror M11 and the PSL environmental controls were on for a couple hours. We're watching things for time being, hoping that PMC Refl comes back to "normal" once the enclosure thermalizes; if it doesn't then either Ryan S. or myself will do a quick alignment tweak at an available opportunity (or next Tuesday if no opportunistic time pops up between now and then). Probably more to come here.
This closes LHO WP 11881.
J. Kissel, [emotional support from L. Dartez remotely] Executive Summary Contrary to the grand plan, I instead unplugged and re-plugged in some cables, and lost 4 hours of my life. The OMC DCPD electronics chain remains as it did before today. I'm confused yet again. Full Summary After we last left the saga of "the in-vacuum OMC DCPD Transimpedance Amplifier (TIA) frequency response has changed a little since the OMC Swap; let's re-measure it in analog" (LHO:77735), the 2024-May-13 plan was to swap the apparently broken S2300003, D2200215-style OMC DCPD Whitening Chassis, for a spare (I chose S2300002), in hopes that we'd be able to make a new analog measurement of the TIA without the non-linearity in the whitening chassis' measurement setup. Today, the installed-in-the-racks measurement setup using S2300002 got even more weird :: very different from the exact same setup of the same chassis in the EE shop. "Weird" is :: 2 [V/V] rather than 1 [V/V], and :: a very obvious, 10 [%] / 3 [deg] wiggle, frequency response above 1 kHz, rather than "subtle, slightly different nonlinear roll off." Indeed, to confirm my insanity, I quickly switched over to CH B of S2300003 while there with everything else the same, and it's similarly weird -- and different from the previous in-rack measurements taken only a few weeks ago where I'd probed its subtle non-linearity around 1 [V/V]. Just maddening. That being said, after dividing the maddening response of the measurement setup out of the data we really want -- the analog measurement of the in-vacuum TIA -- we see a good clean measurement, with finally with the same DC gain as the good old 2023-03-10 measurements. BUT -- DCPD A's response shows change from the best 2023-03-10 measurement data set -- but at *high* frequency rather than "below 25 Hz." I don't think this is real. More on this in a follow-up aLOG. In the end, after four hours in front of the SR785, Louis and I decided to revert the signal chain back to using S2300003 as had and has been the case for all of O4. I'll hang my head, eat my hat, put foot in mouth, and head back to the EE shop. Attached is a collection of plots the shows today's results. :: Pages 1 & 2, for DCPDA and DCPDB, respectively, the TIA response, with the maddening measurement setup divided out. One can see that the for DCPDB (page 2) that today's 2024-05-28 measurement divided by the currently installed compensation (from 2023-03-10) agrees very well with the 2023-03-10 measurement over compensation. However, for DCPDA (page 1), we see a diverence from the model and old measurement above 1 kHz. :: Pages 3 & 4, for DCPDA and DCPDB, again show the obscene difference between today's measurement setup's response -- the 2 [V/V], with 10 % / 3 deg wiggle above 1 kHz -- and the previous "bad" result from 2024-04-23, and the originally "I'm happy with that" 2023-03-10 result, both of which are 1 [V/V] with "a little bit of phase loss, but that's it." :: Page 5 shows the ratio of all of today's measurement setup responses, showing that even from channel to channel and chassis to chassis, I get this exact same response. I even swapped out the SR785 accessory box for another to see if this was the issue, and I got the same response. The only piece of electronics left as suspect is the SR785. But -- (1) Out of the utmost caution, I run a factory reset on any SR785 I touch before I begin configuring it for measurement, and (2) This is a *differential* transfer function measurement with the SR785. That means the ratio CH2 (A-B) / CH1 (A-B) is changing. I find it quite hard to believe that this could be happening. And in case you're suspicious that "Oh, you must have blown the input electronics by driving too hard into it," We're careful to keep the input voltage for each A and B spigot of CH1 and CH2 below the specified 5 [V_pk], and we're watching for its ADC saturations at all times. So, ya, maddening. More details in the comments for posterity.
First attachment: pictures of the momentary installation of S2300002 into ISC-R5, both where I landed it in U26, and then followed up with pictures of the measurement while measuring it. Second attachment: A copy forward of the diagrams of the measurement setup that I followed during the above measurements. (The pictures from above show it while I was measuring the TIA; I did not take pictures of the measurement setup, but I *promise* you it matches the diagram. I checked 15 times once things started to go pear-shaped with the frequency-dependent, 2 [V/V], business.) Third attachment: A post-mortem collection of photos proving that the system has been completely reverted, leaving only S2300003 in U24, with all cables reconnected.
The data and script to quickly plot it from today's work lives in /ligo/svncommon/CalSVN/aligocalibration/trunk/ Common/Electronics/H1/DCPDTransimpedanceAmp/OMCA/S2100832_SN02/20240528/Data/ I attach the measurement notes.
It was the SR785 that has been slowly failing in a subtle way. That's why the "measurement setup" measurements have been continually changing, and in this aLOG look totally bonkers with the 2 [V/V] and a frequency-dependent wiggle above 1 kHz. See LHO:78165.
Andrei, Sheila
We've analyzed the time-traces of the effective range (H1:CDS-SENSMON_CAL_SNSW_EFFECTIVE_RANGE_MPC
) along with the alignment channels FC_WFC_A(B)
and AS_A(B)_RF42
(see attached figures). We found no observable dependance between those.
During the time period being investigated in this alog on May 27, LASSO flags H1:TCS-ITMX_CO2_ISS_CTRL2_OUT_DQ as strongly correlated with the range. This channel and other related channels have been flagged as highly correlated to the range in recent days, but this time period shows the strongest correlation.
Jumps in this TCS channel correlate with range jumps, as shown in the attached comparison of the TCS and range trends on May 27.
Tagging TCS
This TCSX ISS correlation is a bit odd since we aren't using the ISS and the AOM, I believe, is completely unplugged. That said, I looked at some of the channels in that system and there is some extra noise seen around the times Derek posted (see May 16th example). I wonder if this points to a larger grounding issue or some other electrical problem that is seen more broadly.
These range fluctuations that we think are related to the squeezer started (I think) on May 16th: 77869
The first time cursor in the attached screeshot shows that range drip which I thought was traffic related at the time. Looking at the long term trend of this CO2 ISS control signal, there is a chance in charachter at this time, with more drifts in the signal level since. The second screenshot shows that this channel had a large jump on May 17th around 20:04-22:33 UTC.
There is a DARM BLRMS that may be more useful for tracking this noise than just looking at range, H1:OAF-RANGE_RLP_3_OUTPUT. (third screenshot shows this also had a change point and drifts more since May 16th.)
The LVEA has been swept, the FARO is being left plugged in as usual, there were some ladders left out along the yarm.
Pictures of the OMC IO Chassis.
DCC-D1301004 has been updated
LLO noted a 10 Hz comb that was attributed to the IRIG B monitor channel at the end station connected to the PEM chassis. (https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=71217)
LHO has agreed to remove this signal for a week to see how it impacts our DARM signal.
EX and EY cables have been disconnected.
Disconnection times
EX | GPS 1400946722 | 15:51:44 Tue 28 May 2024 UTC |
EY | GPS 1400947702 | 16:08:04 Tue 28 May 2024 UTC |
I checked H1:CAL-PCALX_IRIGB_DQ at gps=1400946722 and H1:CAL-PCALY_IRIGB_DQ at gps=1400947702. From 10 seconds prior to the cable disconnection to 1 sec before the cable disconnection, IRIG-B code in these channels agreed with the time stamp after taking into account the leap second offset (18 sec currently).
Note that the offset is there because the IRIG-B output from the CNS-II witness GPS clock ignores leap seconds.
I fixed things in https://svn.ligo.caltech.edu/svn/aligocalibration/trunk/Common/Scripts/Timing/ so that they run in the control room with modern gpstime package and also the offset is not hard coded. I committed the changes.
Please reconnect the cable soon so we have independent witness signals of the time stamp. There could be a better implementation but we need the current ones until a proper fix is proposed, approved and implemented.
I have checked the weekly Fscans to look for similar 1 Hz and 10 Hz combs in the H1 data (which we haven't see in the H1 O4 data thus far), or any obvious changes in the H1 spectral artifacts occurring due to the configuration change May 28. I do not see any changes due to this configuration change. This may be because the coupling from the timing IRIG-B signal may be lower at LHO than it is at LLO. I do notice that there is some change around the beginning of May 2024 that the number of line artifacts seems to increase; this should be investigated further. Attached are two figures showing the trend of 1 Hz and 10 Hz comb, where the black points are the average comb power and colored points are the individual comb frequency power values; color of the individual points indicates the frequency. Note that there is no change in the last black data point (the only full-1-week Fscan so far).
The IRIGB cables at EX and EY have been reconnected (PEM AA Chassis CH31).
Naoki, Karmeng, Andrei, Sheila
We did NLG sweep on DARM at NLG 16.9 (nominal) and 42. The IFO was locked for more than 20 hours and well thermalized. We also tried NLG of 65.9, but the squeezing level was not stable so we gave up this NLG. We will take the third NLG data tomorrow if IFO is thermalized.
Previous NLG sweep on DARM: 73747
How to measure NLG: 76542
How to change NLG: 73801
Note:
UTC | demod phase | DTT ref | NLG | SQZ at 2kHz (dB) | |
FDS | 16:29:00-16:34:00 | 160.91 | 3 | 16.9 | -4.2 |
No SQZ | 16:36:20-16:41:20 | 0 | |||
ASQZ | 16:56:20-17:01:20 | -100.37 | 6 | 16.9 | 15.4 |
mean SQZ | 17:11:00-17:16:00 | 7 | 16.9 | 12.6 | |
FDS | 18:02:10-18:07:10 | 162.13 | 4 | 42 | -4.4 |
ASQZ | 18:19:30-18:24:00 | -87.6 | 8 | 42 | 20 |
mean SQZ | 18:29:00-18:34:00 | 9 | 42 | 17 |
OPO trans (uW) | OPO temp | Seed amplified | Seed unamplified | NLG |
80 | 31.470 | 0.215 | 0.0127 | 16.9 |
100 | 31.454 | 0.534 | 0.0127 | 42 |
110 | 31.448 | 0.0725 | 0.0011 | 65.9 |
After PR2 spot move yesterday in 78012, we did NLG sweep again. This time we took three NLG at 7.9, 16.3 (nominal), 55.9.
UTC | demod phase | DTT ref | NLG | SQZ at 2kHz (dB) | |
No SQZ | 16:41:00-16:46:00 | 0 | |||
FDS | 16:54:08-16:59:08 | 161.59 | 10 | 7.9 | -4.4 |
ASQZ | 17:04:00-17:09:00 | -95.63 | 11 | 7.9 | 11.1 |
mean SQZ | 17:10:52-17:15:52 | 12 | 7.9 | 9.1 | |
FDS | 17:31:40-17:36:40 | 192.47 | 13 | 55.9 | -4.1 |
ASQZ | 17:43:54-17:48:54 | -86.42 | 14 | 55.9 | 21.2 |
mean SQZ | 17:50:53-17:55:53 | 55.9 | 18.5 | ||
FDS | 18:12:31-18:17:00 | 190.31 | 15 | 16.3 | -4.7 |
ASQZ | 18:21:54-18:26:54 | -97.79 | 16 | 16.3 | 15.3 |
mean SQZ | 18:28:12-18:33:12 | 17 | 16.3 | 12.5 |
OPO trans (uW) | OPO temp | Seed amplified | Seend unamplified | NLG |
60 | 31.484 | 0.0086 | 0.00109 | 7.9 |
80 | 31.468 | 0.0174 | 0.00107 | 16.3 |
105 | 31.446 | 0.0609 | 0.00109 | 55.9 |
Vicky, Karmeng
This NLG scan is compatible with ~30% SQZ losses, ~20 mrad phase noise.
Attachment 1, 2 - Calculated loss ~30% from mean sqz and generated sqz, then fit ASQZ/SQZ to estimate phase noise ~ 20 mrad and technical noise. If fitting SQZ+ASQZ together to estimate, then fit loss ~32-33%. This uses standard linear opo equations to estimate generated squeezing level based on NLG.
Attachment 3 - Calculated loss ~ 27% from mean sqz and generated sqz, then fit ASQZ/SQZ to estimate phase noise ~ 20 mrad and technical noise. This uses bowtie opo equations to estimate generated squeezing level based on NLG (few % lower generated sqz than the above estimate). See Eq. 13 of Dhruva's ADF paper, e.g. P2200041.
NLG calibration - Estimates OPO green pump trans threshold @ 142 uW. This seems close to previous threshold estimates ~149 uW made just after moving to this crystal spot (LHO:73562, Oct2023 crystal move).
A comparison of O4a (hd,ifo) and O4b NLG (ifo) scans, maybe most interesting is comparing homodyne vs. interferometer squeezing in O4a (~32% loss, LHO:78000). O4a/O4b IFO losses look similar, but I think it's largely an issue with this O4b measurement?
A note about this NLG scan - I think total optical losses should be < 30% based on seeing >5dB SQZ previously. For example, the -5.4 dB SQZ observed in LHO:76553 is too much squeezing, and incompatible with losses >30%. So I think this measurement has higher losses than "normal" in O4b, maybe related to the alignment / mode-matching / (something that drifts) not being optimal here. Would be interesting to get back to the -5dB spot (of course), and see how losses look then.
Code with instructions is here: https://git.ligo.org/victoriaa.xu/nlgscans