Displaying reports 66341-66360 of 83394.Go to page Start 3314 3315 3316 3317 3318 3319 3320 3321 3322 End
Reports until 08:58, Friday 27 March 2015
H1 ISC (CAL, CDS, DetChar, GRD, INS, IOO, ISC, SEI, SUS, SYS)
jeffrey.kissel@LIGO.ORG - posted 08:58, Friday 27 March 2015 - last comment - 07:47, Saturday 28 March 2015(17515)
Great sensitivity all night long!
J. Kissel, J. Warner, J. Romie, H. Radkins, N. Kijbunchoo, K. Izumi, G. Moreno

SUMMARY: We just finished ~7 HOUR lock stretch at our best sensitivity ever, between 32 and 34 [Mpc]!

We've all been pleasantly surprised this morning to see that the lock stretch that Sheila Evan, Dan and Lisa started last night lasted the entire night. Unfortunately, as of ~10 minutes ago (~8:40a PDT, ~15:40 UTC), there are GIANT glitches and non-stationarity that keep popping up, spoiling the sensitivity. There's no one in the LVEA, so we're not at all sure what's caused the sudden change in behaviour. Wind seems fine at ~5 [mph], ground motion is still pretty low, the 1-3 [Hz] hasn't even come up yet.

Anxious to explore things, Jim installed some low-pass filters in the HAM5 and HAM6 ISIs at around 8:45 to try to reduce scattering / acoustic coupling to the ISI, and Kiwamu began exploring MICH coupling to DARM. 

But, as I write this log, we lost lock. However, for DetChar purposes, one can assume the detector was undisturbed from March 27 9:00 UTC to March 27 ~15:00 UTC.

Comments related to this report
jeffrey.kissel@LIGO.ORG - 09:17, Friday 27 March 2015 (17516)
K. Izumi, J. Kissel

For the record: Kiwamu drove down to the EY end station to check: *this* lock loss did *not* cause the EY ESD Driver to trip. Huh.
gabriele.vajente@LIGO.ORG - 11:21, Friday 27 March 2015 (17526)DetChar, ISC

Looking at spectrograms of DARM during the first hour of lock (first plot) and the last hour (second plot), it seems to me that the noise is more or less stationary, but there are huge glitches. They are so big that you can even see them easily in time domain (third plot). A zoom in is visible in the fourth plot. They look like bursts of oscillations at about 5.5 kHz.

Images attached to this comment
kiwamu.izumi@LIGO.ORG - 13:44, Friday 27 March 2015 (17532)

We now believe that the glitches we had in the lock stretch from this morning was due to the ISS which repeatedly unlocked. This is a typical behavior of the ISS when the diffraction power is too low. Indeed the diffracted power had been 4% on average during the time when the interferometer was locked. There was clear correlation between arm cavities' power and the ISS diffracted power. See the attached trend of some relevant channels. Elli adjusted the diffracted power in this after noon so that the diffracted power is now at 8% with only the inner loop closed.

Images attached to this comment
thomas.massinger@LIGO.ORG - 18:24, Friday 27 March 2015 (17540)DetChar

Looking at glitch-to-glitch coupling between auxiliary channels and DARM shows a large number of glitches in the > 1kHz range that are coincident with glitches in CARM, REFL 9 PIT/YAW, and REFL 45 PIT. Interestingly, CARM is highly correlated with high frequency glitches until about 12:00:00 UTC, at which point REFL 45 PIT becomes the stronger veto.

It looks like REFL 45 Q PIT was offset by about 2500 counts during the lock, is it possible that intensity fluctuations on an uncentered WFS are showing up as alignment glitches? I've attached a time series covering 2 hours of the lock from 11 UTC to 13 UTC.

We're currently running code to see if the lower frequency (50-200 Hz) glitches are caused by zero-crossings in the 18-bit DACs.

I've attached an Omicron glitchgram for the whole day, it seems as if the higher frequency glitches and the glitches populating the 50-200 Hz region are the two dominant populations right now. There are also a few high SNR glitches scattered around in the 100-400 Hz region that we'll follow up individually.

Images attached to this comment
joshua.smith@LIGO.ORG - 07:47, Saturday 28 March 2015 (17555)DetChar

-2^16 Crossings in ETMY L3 ESD causing many of the glitches in this lock:

In addition to the arches reported in 17452 and 17506 we found DAC glitches in this lock when ETMY L3 ESD DAC outputs were crossing -2^16 counts. Attached is a PDF with a few examples that were lined up by hand. We will follow up more closely to see if other suspensions and penultimate stages also add glitches. Note: At Livingston, SUS MC2 M3 DACs were also a problem. 

If you'd like to see the primary culprits from this long lock, here is a tar file of omega scans (thanks to Joe Areeda) of the loudest 100 glitches between 30 and 200Hz. The vertical lines that repeat are DAC glitches, the crazy wandering features are the arches described in the pages linked above, those two mechanisms account for most of the glitches we see.   

Non-image files attached to this comment
H1 AOS
david.barker@LIGO.ORG - posted 08:04, Friday 27 March 2015 (17510)
CDS model and DAQ restart report, Thursday 26th March 2015

model restarts logged for Thu 26/Mar/2015
2015_03_26 00:32 h1fw1
2015_03_26 08:55 h1calcs
2015_03_26 08:57 h1omc

2015_03_26 09:03 h1broadcast0
2015_03_26 09:03 h1dc0
2015_03_26 09:03 h1fw0
2015_03_26 09:03 h1fw1
2015_03_26 09:03 h1nds0
2015_03_26 09:03 h1nds1

2015_03_26 14:44 h1fw0

two unexpected restarts. CAL and OMC model work, with associated DAQ restart.

LHO VE
bubba.gateley@LIGO.ORG - posted 06:54, Friday 27 March 2015 (17507)
Beam Tube Washing
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.
H1 DetChar
andrew.lundgren@LIGO.ORG - posted 04:34, Friday 27 March 2015 - last comment - 02:08, Saturday 28 March 2015(17506)
Whistles in DARM in current lock
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.
Images attached to this report
Comments related to this report
andrew.lundgren@LIGO.ORG - 02:08, Saturday 28 March 2015 (17554)
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.
Non-image files attached to this comment
H1 ISC (ISC)
lisa.barsotti@LIGO.ORG - posted 02:12, Friday 27 March 2015 - last comment - 12:17, Friday 27 March 2015(17504)
30 is the new 20!

Evan, Sheila, Dan, Lisa

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

We leave the interferometer locked at 34 Mpc, starting at March 27 9:00 UTC

Comments related to this report
evan.hall@LIGO.ORG - 02:17, Friday 27 March 2015 (17505)

Spectrum attached.

Images attached to this comment
fred.raab@LIGO.ORG - 07:41, Friday 27 March 2015 (17509)
Great work! I will update our slides for the quarterly briefing.
albert.lazzarini@LIGO.ORG - 08:40, Friday 27 March 2015 (17511)
Excellent progress!
david.reitze@LIGO.ORG - 08:47, Friday 27 March 2015 (17514)
Nice work.  Great headline, too.
hugh.radkins@LIGO.ORG - 09:38, Friday 27 March 2015 (17518)

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.

Images attached to this comment
evan.hall@LIGO.ORG - 12:17, Friday 27 March 2015 (17530)

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.

Non-image files attached to this comment
H1 ISC
daniel.hoak@LIGO.ORG - posted 01:25, Friday 27 March 2015 - last comment - 08:46, Friday 27 March 2015(17502)
some new violin data

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.

Comments related to this report
david.reitze@LIGO.ORG - 08:46, Friday 27 March 2015 (17513)


		
		
H1 SUS
sheila.dwyer@LIGO.ORG - posted 00:57, Friday 27 March 2015 - last comment - 11:33, Friday 27 March 2015(17501)
EX PUM watchdog

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

Comments related to this report
thomas.shaffer@LIGO.ORG - 11:33, Friday 27 March 2015 (17527)

They are now in SYS_DIAG.

H1 PEM (DetChar, ISC, PEM)
sheila.dwyer@LIGO.ORG - posted 21:54, Thursday 26 March 2015 - last comment - 18:49, Friday 27 March 2015(17499)
Coherence with PEM accelerometers

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.  

Images attached to this report
Comments related to this report
sudarshan.karki@LIGO.ORG - 18:49, Friday 27 March 2015 (17542)

There is some cabling work that needed to be completed on this particular channel (ISCT6_ACC). Hope to bring it online on Monday.

H1 ISC
sheila.dwyer@LIGO.ORG - posted 19:58, Thursday 26 March 2015 (17497)
Where our megaparsecs are

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.  

Non-image files attached to this report
H1 SUS (CDS, ISC, SUS)
evan.hall@LIGO.ORG - posted 18:18, Thursday 26 March 2015 - last comment - 07:00, Friday 27 March 2015(17496)
ETMY ESD driver tripping repeatedly

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.

Comments related to this report
sheila.dwyer@LIGO.ORG - 00:55, Friday 27 March 2015 (17500)

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.  

kiwamu.izumi@LIGO.ORG - 07:00, Friday 27 March 2015 (17508)

Why don't we set a digital limiter ? For example, see LLO alog:

https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=14472

H1 SEI (ISC)
hugh.radkins@LIGO.ORG - posted 11:00, Thursday 26 March 2015 - last comment - 02:00, Friday 27 March 2015(17482)
IFO Lock Loss (McCarthy ESD EndY?) Leads to EndX HEPI/ISI Watchdog Trip, Why? Guardian, PLL Logic?

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.

Images attached to this report
Comments related to this report
sheila.dwyer@LIGO.ORG - 02:00, Friday 27 March 2015 (17503)

There were two things in place that should have prevented this but didn't.

  •  First of  all the guardian should have noticed that the lock was lost and gone to the down state, which clears the DARM drive to the ETM, so that the input to the tidal on ETMX sus should be zero, and therefore the input to HEPI tidal should have been zero.   The guardian was in the state DRMI_ON_POP, which had a typo from some efforts to incorporate new functionality.  I assume that the guardian didn't go to down because it would have been in error with this typo.
  • Second, the logic in the end station state machine in beckhoff should turn off the tidal feedback when the arm is not locked.  It did this, which is why HEPI didn't trip right away despite the guardian problem.  However, the new Red Lcoked state can be entered when there is just a flash of red in the arms, without passing through the other states, which it should not be doing.  This can be fixed, hopefully on tuesday.  
H1 SUS (DetChar)
richard.mccarthy@LIGO.ORG - posted 07:47, Thursday 26 March 2015 - last comment - 19:52, Thursday 26 March 2015(17479)
ETMY ESD drive
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.

Comments related to this report
rainer.weiss@LIGO.ORG - 19:52, Thursday 26 March 2015 (17498)
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.
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