Scott L. Ed P. Chris S. My apologizes for this late report from yesterday. I had to leave early to get to town and pick up oil filters for the new generator, already time for P Ms. The cleaning crew was able to clean 76 meters of tube yesterday towards X-1-7 double doors. Good day.
The whistles in DARM are still quite prominent in this lock. As briefly summarized in this alog, they happen whenever the PSL VCO frequency crosses 79.2 MHz. This points to the likely cause. This is a reliable enough indicator that we can get some statistics. In the first hour of the current lock (Mar 27 9 UTC to 10 UTC), the whistles happen at a rate of 4 per minute. Below are four spectrograms. The first two show some whistles identified this way. A new feature is that there seems to be a second oscillator very close by, or maybe some harmonic of the beat note. The next two spectrograms show a minute with several whistles, and the next minute where none occurred. Even when none go through zero frequency, you can still see the beat note hovering up near Nyquist.
The attached script will find all the crossings which indicate whistle / RF beat note glitches due to the 79.2 MHz crossing. Currently the PSL VCO readback only appears to be changing once a second, so the time accuracy of glitch finding is only one second. For vetoing purposes, this could be improved by doing a linear fit of IMC-F to the PSL VCO readback, then using the much faster sampled IMC-F to measure the VCO frequency.
We made it to 34 Mpc by managing to do at the same time all of the things we have tried before (low noise ESD on ETMY, low noise coil drivers for all the optics, POPAIR for vertex length DOF, more aggressive SRCL cut-off), plus some more ASC cut-offs. Implementing all of these things at the same time happened to be more challenging that expected because of a few problems that slowed us down today:
Some more details
Final IFO & Guardian state
Spectrum attached.
Great work! I will update our slides for the quarterly briefing.
Excellent progress!
Nice work. Great headline, too.
Note that ISI Stage2 was a State3 trip meaning that the Damping Loops were still functional. It would be nice to know when/why the stage tripped. But I'd guess that the Guardian was set to fully isolated before the ~0700utc short lock and was untripped during the short lock, likely triggering during acquisition and then triggering again at the trip. That is what I first thought.
See attached--It looks like the stage2 when isolated survived the IFO lock loss but not the MICH reacquisition. This means, we can use the Guardian to transition the ISI between Isolated Damped and Fully Isolated with tripping nor requiring operator intervention.
This is a 50 minute stretch so the IFO lock Loss is only a couple minutes before the St2 WD trigger but there may be enough time to deisolate stage2. Looking at a zoomed in full data, looks like a full 70+ seconds after lock loss based on this CAL_DELTAL channel. The second lock loss had even more time so I don't think it is tied to the lock loss but more to the reacquisition.
Noise budget attached, with new the anticipated ETMY ESD noise. We have many other traces to add here: intensity coupling, frequency coupling, auxiliary dofs, etc.
I believe the 10 W quantum noise and the DAC→ESD noise alone limit us to no more than 60 Mpc, although based on the previous performance of the ETMX ESD, the ESD trace here may be an overestimate.
Evan & Sheila, Dan & Lisa
Tonight some new failure modes of the violin damping manifested themselves, and we found new ways to damp them.
On ITMY, the following modes and settings were identified:
| Frequency (Hz) | Filter (ITMY_L2_DAMP) | Settings (phase, gain) |
| 503.007 | MODE3 | +60deg, +200 |
| 503.119 | MODE1 | -60deg, -300 |
| 504.875 | MODE4 | 0deg, +300 |
Note that in the earlier catalog the 504.875 line was mis-identified as an ETMX mode, and the 503.119 line was not paired with an optic.
Earlier in the evening we tripped the RMS watchdog on ETMX, and had to drive out the end station to power cycle the coil driver.
This wasn't obvious from the control room. Three things that would help are to
1) add this to the OPS overview screen
2) add it to the SYS_DIAG gaurdian
3) add it to the SUS guardians
They are now in SYS_DIAG.
Here is a plot of coherences with some PEM accelerometers. We have been thinking that the noise around 200-250 Hz was due to the PSL periscope PZT, based on coherences like the one in the lower left plot. However, there is suscpicously similar coherence between the ISCT6 accelerometer and DARM. Indeed, the coherence between these two accelerometers is high in this frequency range, suggesting that some cross talk could be the dominant signal in these accelerometers.
The right two panels show that the accelerometers which have coherence with DARM around 13 Hz and 16 Hz are also coherent with each other, but not nearly as much.
There is some cabling work that needed to be completed on this particular channel (ISCT6_ACC). Hope to bring it online on Monday.
The first plot here shows the range integrand for LLO's 65 Mpc lock on March 6th, our March 16th 15 Mpc lock and Monday's 28 Mpc lock. The second plot shows the cumulative range difference as a function of frequency between these locks.
The green line on the second plot shows that the 12 Mpc we gained between March 16th and is mainly due to the improvements from 20-100 Mpc, (mainly due to ESD low passes and decreased MICH contamination of DARM).
The blue line shows where we need to improve to catch up with LLO in inspiral range There are 25 Mpc to be had in the 20-40 Hz region.
These plots are made using an old script by Grant Meadors, and data that Dan managed to get for LLO.
Rich A., Lisa, Sheila, Jeff, Evan
The EY ESD driver has tripped twice today, apparently in the same failure mode as described previously. Each time we have had to drive down to the end station to reactivate it.
The supplies are set at ±430 V, each with a 75 mA current limit. When the driver is active, it draws 23 mA dc from the positive supply and 20 mA dc from the negative supply. When tripped, it draws 3 mA dc from each supply.
This seems to happen every time we loose lock if we have transitioned to ETMY. We are getting plenty of excerise tonight going back and forth to the end station.
If anyone has any ideas about how to make this easier to reset or to prevent it from happening, that would save us some fuel.
Why don't we set a digital limiter ? For example, see LLO alog:
https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=14472
J. Kissel Completes WP #5118 I've compiled, installed, restarted, and restored the changes to the h1calcs.mdl and h1omc.mdl front end models that were described in LHO aLOG 17472. This required a DAQ / h1dc0 / frame-builder restart, which I performed at 09:02 PDT (16:02 UTC). I attach screenshots of further improved MEDM screens for the CAL CS and LSC that employ the new channels. I've also turned on the OMC SDF system, and committed the new SDF file "safe.snap" to the userapps repo, under /opt/rtcds/userapps/release/omc/h1/burtfiles/h1omc_safe.snap. It currently has 28 channels not monitored, the only one of which I delibrately turned off was H1:OMC-PZT2_SW2S, which had its output flickering on and off because of the front-end / guardian triggering which toggles the output. The rest appear to be ODC strings that I guess, by default, aren't monitored. Note that this SDF system covers a lot of the LSC stuff too, and it looks like the majority of channels that are different from this morning (when I turned on the SDF, when the ISC_LOCK and OMC_LOCK manager were DOWN) are Guardian changed variables. When the IFO was fully locked in the DC readout, and the vanguard was in the process of transitioning to low-noise ETMY control, there were only 20 channels in the DIFF list. I leave it to the commissioning vanguard to remove these channels from the list at leisure. This will be much easier / convenient to do once we get the RCG 2.9.1 upgrade to the SDF system.
= Morning Meeting =
SEI: BRS rung up
SUS: Sorry I couldn't hear
Richard: Shutter control needs work
Facility: Sorry, I couldn't hear again
3IFO: Moving things next Tuesday. Will be noisy.
Jeff: Rebotting calibration front end model
Sudarshan: PCal calibration
Lots of work permits...
= Activities =
Some times early in the morning: Karen and Cris to LVEA
7:00 Richard to EY
7:37 Richard back
8:19 Karen opening exit doors (LVEA)
8:41 Jim B to EY. Installing TCT
8:45 Fil to EY replace shutter box
Sudarshan and Rick to EX - PCal work
Jim to EX (stopped BRS damp)
8:52 Matt and Jason to H1 PSL ante room
5:56 Kyle to EY
9:00 both Jim came back
9:06 Jeff done with model changing
9:12 Matt and Jason back
9:19 Betsy and Travisto West Bay (3IFO stuff)
9:34 Kyle out of EY, to EX
9:39 Fil back
10:02 Kyle back
10:05 Andreas drop a bag at LVEA
10:18 Andreas back
10:30 Richard to LVEA 2k area (3IFO)
Jodi to LVEA
11:29 Jodi let Gary in, supervised.
12:00 Daniel and Sheila to EY
12:40 Corey to squeezer bay
13:46 Jodi back
13:51 Dan and Eli to EY
13:54 Rick and Sudarshan leaving EX
14:40 Dan and Eli back
Corey back
Happy 3IFO day
I took out ISC_DOF since it is no longer being used. Since this left a hole, I slid up the SYS_DIAG mini.
Screenshot attached.
A couple of plots from last night. We had an incredibly stable ~4h lock with 20 Mpc range. All the "standard" alignment loops were enaged (the only uncontrolled DOFs are comm/diff ITMs).
Recall that in this lock DARM was controlled by actuating on high noise ESD on ETMX.
Dan, Elli. EX ring heater power supply is turned off. Alll other ring heater power supplies are still on There is a coherence measured between EX magnetometer and DARM at 55Hz (see Gabriele's alog 17423), so we are checking whether turning off the ring heater power supply removes this line.
The 55MHz line didn't disappear, so we have turned off ITM ring heater power supplies also.
I've continued my work on improving BSC St2 blends, I think I have something fairly Hippocratic. I moved the St2 ellips down to 1.5 Hz and added a pole at 10 Hz. This affects the St2 CPS phase (~24 degrees at the blend frequency) but this doesn't seem to negatively affect the performance. I've talked to the commissioners about trying this during a lock, I think I can install and turn the new filters on without breaking anything.
First plot shows my modifications. Red is stock, green is the "old" again, blue is my current.
Second plot shows the performance. Pink is ground before, green is ground after, blue is before, dashed and solid are CPS and GS13 respectively, red is after. Does pretty good between 1 and 20 hz, doesn't seem to do any worse below 1 hz. I think all of the differences below 1 hz can be attributed to the ground.
Jeff suggested I check LLO' blends to see if they had made a similar change, and it turns out they have. A nice demonstration of convergent evolution. Attached plots show the comparisons. The LLO blend has more gain peaking, but keeps closer phase up to the blend frequency and has more high frequency roll off. My elliptics dont afftect the gain peaking, but don't roll off as fast around 10 hz, but at that point my performance plots show we are already hitting GS13 noise.
Sheila, Hugh
IFO lost lock ~1426utc, Richard suspects it was his testing of the ESD. Almost 45 minutes later, the ISCINF_LONG stepped to its rail, LIMIT set to 250000nm. And I mean stepped, ~1 second or less. This of course put a bit much demand on the HEPI loop. It spiked its output and pretty much instantly tripped the watchdog on the Actuator followed by the ISI shortly thereafter. The HEPI and ISI reisolated normally.
The first attached plot shows the lock loss. This 30 minute trend has the DARM OUT with the ISCMON_X_INMON quickly going to zero and the HEPI Outputs moving in response. No problems here, HEPI does fine. You also see the arm or something grab again as you can see the Tidal drive to the HEPI start again but this only lasted for a couple minutes.
The second plot attached zooms out to 2 hours, with the IFO lock loss seen on the ISCMON on the left. ~45 minutes later the DARM steps, this time stepping the ISCMON and tripping HEPI and about 8 seconds later, the ISI (not shown.)
In the third attachment, Sheila dug around in LSC/ALS space and put together some trends showing the spike into HEPI originating when the ALS-X_LOCK_STATE steps from level 2 to 6 (PLL Lock to Red Lock.) This is unrealistic as the Lock state dropped from Red Lock just ~90 seconds earlier. Notice the TIDAL_CTRL_INMON steadily growing (DARM not Cleared.)
Sheila is looking deeper into the Guardian feeling it may have failed to do something it possibly should have to prevent the DARM OUT from going to the rail and the unreasonable rapid transitions of the ALS LOCK STATE.
There were two things in place that should have prevented this but didn't.
Loss of lock probably due to my work at EY on ESD drive. Following up on last nights report I went down to EY to investigate problems with the ESD. Much to my surprise aside from the unit being in the off state I could not find a problem. The HV supplies were on and at nominal current draw for no drive (3.2mA). Went in to check the ESD Chassis and all the lights were green. The only indication of a problem was the main indicating light for the unit showed it to be in the off state. I had disabled all of the DAC inputs to the driver so I turned it on. Went over to computer and enabled outputs and immediately saw a response on the OpLev. I am not sure what interlock could have shut the unit down but further investigation is warranted. I have left the unit on for now. please keep me Richard McCarthy informed if this or more problems arise.
When I was characterizing the ESD several years ago I noticed that the microprocessor that controls the device would turn off the system when a spike in either + or - direction on the 430 volts input occurs. You might want to check the tolerance on the input voltage of both the positive and negative input voltages.
