Displaying reports 36001-36020 of 89220.Go to page Start 1797 1798 1799 1800 1801 1802 1803 1804 1805 End
Reports until 16:22, Thursday 30 January 2020
H1 PSL
jason.oberling@LIGO.ORG - posted 16:22, Thursday 30 January 2020 (54820)
PSL FSS Measurements from 1/28/2020

J. Oberling, R. Savage, E. Merilh

Noting some of the recent issues with RefCav relocking, we went into the PSL to take some measurements of the FSS to see if we could gather some clues as to what's going on.  We began by taking a transfer function and immediately noticed something odd, see first attachment (FSS2.tif).  Out around 775kHz there is a large bump that rises above the UFG (please recall that the UGF for the FSS is read at -10dB due to the design of the TTFSS electronics; in this case it is just below 500kHz), with a corresponding bump in the phase.  Looking at the last TF we took, the bump in magnitude was present, but smaller than it is now, with no corresponding bump in the phase; this therefore, is a change in the TF since mid-December.  Zooming in on the area (2nd attachment, FSS3.tif) shows it to be more than a simple bump, but a series of them culminating in a large hump at ~776kHz that rises almost 10dB above the UGF.  We took a spectrum of the IN1 port on the TTFSS (closest to the mixer) and while it looked a bit "spikey" (for lack of a better word), the area around the hump looked different; more flat, but with a dip and return (with a spike in the middle of this), followed by a small bump (see third attachment, FSS6.tif).  Thinking this could be an indication of an issue with the NPRO noise eater (the noise eater (NE) supresses the natural relaxation oscillation of the NPRO crystal, which tends to hang out in this area (each laser is different)), so we repeated the IN1 spectrum with the noise eater ON and OFF; see 4th and 5th attachments, FSS8.tif (NE OFF) & FSS9.tif (NE ON).  As can be seen, the relaxation oscillation peaks around 928kHz, with the hump starting above 800kHz and ending around 1MHz; with the NE ON, the relaxation oscillation disappears; in both, the area below 800kHz is unchanged,indicating that the NPRO NE is not the problem.

We're still digesting this info, but having a hump beyond the UGF that pops up above it is likely the underlying cause of our recent FSS instabilities; at this point we're not sure what's causing this.  Rick suspects that we may have some kind of parallel path resonance happening, or maybe there's a notch in this version of the TTFSS that we need to re-tune.  I've added 1 final picture, FSS13.tif.  In this pic the marker is at the current FSS UGF of ~486kHz; at 10dB/div, it is very clear that this feature at 776kHz is at least 10dB above the UGF.  Investigation continues.

Images attached to this report
H1 General
camilla.compton@LIGO.ORG - posted 16:09, Thursday 30 January 2020 (54824)
Shift transition to Eve

TITLE: 01/30 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 115Mpc
OUTGOING OPERATOR: Jim
CURRENT ENVIRONMENT:
    SEI_CONF state: WINDY
    Wind: 10mph Gusts, 7mph 5min avg
    Primary useism: 0.09 μm/s
    Secondary useism: 0.50 μm/s
QUICK SUMMARY: We have been in observing fro 30 minutes.

H1 General
jim.warner@LIGO.ORG - posted 15:53, Thursday 30 January 2020 (54823)
Shift Summary

TITLE: 01/30 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 119Mpc
INCOMING OPERATOR: Camilla
SHIFT SUMMARY:
LOG:

16:15 Lockloss

18:00 Kyle Gerardo to EY

20:49 Sheila starting squeezer commissioning

21:20 Back to observing

22:10 More squeezing work

23:40 Back to Observe

H1 AOS
sheila.dwyer@LIGO.ORG - posted 15:43, Thursday 30 January 2020 (54822)
SQZ green power increased

After having trouble earlier (54819), we were able to scan the squeezer with 13.7mW of injected green power.  I will make plots with the correlated noise subtracted and post them when ready.  

Earlier in this lock our range was ~116Mpc, but we saw during the scan that for CLF demod angles aroun 105degrees we could get 120 Mpc.  We have left the injected power at 13.7mW and the demod angle at 105 to get a few extra Mpc. 

Images attached to this report
H1 OpsInfo (DetChar)
jim.warner@LIGO.ORG - posted 13:27, Thursday 30 January 2020 (54819)
Squeezer off for a while

Sheila had to back out of some work on the squeezer. She wasn't able to get the squeezer back up, so we not squeezing right now. This has dropped our range down to ~100 mpc. Not sure when the commissioners will be able to recover.

LHO General
kyle.ryan@LIGO.ORG - posted 10:57, Thursday 30 January 2020 (54818)
~0945 - 1045 hrs. local -> Moved new Turbo Pump Station from MY to EX

Gerardo M., Kyle R.

This was a T.O.O. task as the IFO was out-of-lock. 

This new Turbo is slated to be installed during this upcomming (8 hour) maintenance Tuesday.  Having moved this to the EX prior to Tuesday will greatly improve the likelyhood that we can complete the installation within the alotted 8hrs. 

H1 SEI
jim.warner@LIGO.ORG - posted 09:39, Thursday 30 January 2020 (54814)
Tweaking BS ISI ST2 boosts

Back in October, I had worked on the BS St2 boosts to try to reduce locklosses caused by engaging the ST2 loops. I had noticed a few times that we still got kicks here, and I had a lockloss earlier today. I reduced the ramp times on the boosts for the X Y Z and RZ loops to 2 seconds, from 3. The last couple of DRMI acquisitions have had this change running, and I haven't noticed the wiggles in DRMI that I was seeing before. I'll try to get a more detailed look, after we get locked again.

H1 CDS
david.barker@LIGO.ORG - posted 08:23, Thursday 30 January 2020 - last comment - 10:51, Thursday 30 January 2020(54813)
restarted external alert system

While H1 is out of lock I restarted the lv_alert external alert service on the ext-alert virtual machine. This is the second time I have had to do this this week.

Comments related to this report
thomas.shaffer@LIGO.ORG - 10:51, Thursday 30 January 2020 (54817)OpsInfo
Link

This looks to be the known issue of the LVAlert subscriptions silently disappearing (I can't seem to find the link to where the bug is reported). This used to happen once in a blue moon, but lately it seems to be more frequent.

I talked with Jonathan and I'll write a script to monitor the heartbeat and then restart the systemd process if it flatlines. This should automatically take care of the resubscribing to the LVAlert nodes that we need.

In the mean time, Operators if you see the "GraceDb Query Failure" icon on the ops overview, please see the wiki in the follow link for instructions to restart the LVAlert service. https://cdswiki.ligo-wa.caltech.edu/wiki/RestartingLVAlert

LHO General
corey.gray@LIGO.ORG - posted 08:02, Thursday 30 January 2020 (54809)
Owl Ops Shift Summary

TITLE: 01/30 Owl Shift: 08:00-16:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Earthquake
INCOMING OPERATOR: Jim
SHIFT SUMMARY:

H1's been locked 7+hrs  with decent range.  SEI_CONF is in WINDY.

GraceDB query failure continues.  I asked LLO (talked to Doug L & later Danny S----thanks to both of you!!) to give us any notifications they receive.  I sent an email about this to LHO CDS Admin.
LOG:

LHO FMCS
corey.gray@LIGO.ORG - posted 06:23, Thursday 30 January 2020 (54812)
MY Air Handler Alarm

Received an FMCS Air Handler Alarm, but trends (attached) of the air handler and chiller at MY look reasonable.

Images attached to this report
LHO General
corey.gray@LIGO.ORG - posted 04:04, Thursday 30 January 2020 (54811)
Mid Shift Status

Fairly smooth running of H1 with 3+hrs of lock.  There is an inbound Mediterranean 5.9 EQ, so will be monitoring.  GraceDB is still down here at LHO.

H1 General
corey.gray@LIGO.ORG - posted 01:17, Thursday 30 January 2020 - last comment - 10:13, Thursday 30 January 2020(54810)
Back To Observing

After the lockloss at ENGAGE SOFT LOOPS, I made sure to have ndscopes for ASC & ADS Lines up to watch for the next lock. 

Sure enough, made it through with no issues at Soft Loops.  Next scary spot lately has been LOWNOISE_ASC, but we made it through there with no issues.

Not sure what helped with getting to NLN, but will note the following:

  1. H1 seems to rarely make it up on 1st attempt (in the ~40mins it takes H1 to move through ISC_LOCK to NLN).  Seems like H1 needs to have atleast 90+min to have a chance to get to NLN.  Is there still a thermal issue at play here? 
  2. Switched SEI_CONF back to WINDY for this lock.

P.S. Had teeny tiny 10^-17 SDF diffs for a couple of ALS channels, so I ACCEPTED (diffs are attached).

Images attached to this report
Comments related to this report
jenne.driggers@LIGO.ORG - 10:13, Thursday 30 January 2020 (54815)
Link

I have modified the scripts that write these values to ensure that they get rounded also in the case of a ctrl-c exit, so hopefully we won't see these anymore.  When I check the Xarm green initial alignment setpoints on Tuesday, I will test the new rounding.

LHO General
corey.gray@LIGO.ORG - posted 00:24, Thursday 30 January 2020 (54808)
Transition to OWL Shift

TITLE: 01/30 Owl Shift: 08:00-16:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Earthquake
OUTGOING OPERATOR: Camilla
CURRENT ENVIRONMENT:
    SEI_CONF state: USEISM
    Wind: 5mph Gusts, 3mph 5min avg
    Primary useism: 0.05 μm/s
    Secondary useism: 0.69 μm/s

Microseism looks like it's started a decrease over the last 4hrs.
QUICK SUMMARY:

H1 General (PSL)
camilla.compton@LIGO.ORG - posted 00:05, Thursday 30 January 2020 (54801)
Shift Summary - Eve

TITLE: 01/30 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Earthquake
INCOMING OPERATOR: Corey
SHIFT SUMMARY: Lockloss (maybe) from a 5.1M EQ in Mexico. Passing off to Corey with DRMI locked.
LOG:

H1 General (SEI)
camilla.compton@LIGO.ORG - posted 23:17, Wednesday 29 January 2020 (54807)
H1 Lockloss 07:06 UTC
Incoming 5.1M EQ from Mexico.
I'm not sure if the lockloss was caused by the ground motion or state change from USEISM to USEISM_EQ. Plot attahced shows state change (middle plot) then lockloss (top plot) which happened before the ground montion had increased above 400 in peakmon.
Images attached to this report
H1 ISC
jenne.driggers@LIGO.ORG - posted 18:59, Wednesday 29 January 2020 - last comment - 10:14, Thursday 30 January 2020(54798)
Yarm initial alignment setpoints reset

[Camilla, Jenne, Sheila, Keita]

Camilla had several locklosses at ENGAGE_SOFT_LOOPS again tonight.  Normally the remedy is to go back and do another initial alignment, but Sheila pointed out that in all of the lock attempts the Yarm isn't arriving at the engage ASC states very close to the correct alignment.  Since this has been true even after fresh initial alignments, this is indicative of the inital alignment setpoints not being very good. 

We checked, and this is not at all related to the camera network/freezing issues of late.  Every time the camera setpoints come back correctly to the values that were last changed at the end of October.  So, this is likely just that things have drifted over the last ~3 months and the initial alignment setpoints just needed updating. 

Since we had been failing to even engage the soft loops, we hand-moved the Yarm soft using the script ....userapps/asc/h1/move_ARM_dev.py in steps of "YS P 0.03" to get the ADS DOF 5 Pit a bit closer to zero.  When it was off the limiter rail (but not yet all the way to zero), we let the guardian finish the soft loop alignment to the centers of the optics by letting it do ENGAGE_SOFT_LOOPS.  Once all of the soft loops had converged, we checked that the Yarm green was resonating the TEM00 mode, and saw that the green WFS and camera values were not close to zero.  So, we ran the script ....userapps/als/h1/scripts/setEndGreenQPDOffsets_YARM.py to change the WFS centering setpoints, and once that was finished we also set the camera values. 

The Xarm green didn't want to catch the 00 mode, and since the Xarm ADS hasn't been a problem we elected to go forward with locking.  We lost lock later in the sequence, so did an initial alignment to confirm that we can reacquire with these updated Yarm initial alignment setpoints.  I have on the board to check the Xarm setpoints on Tuesday after maintenance.

Attached are screenshots of the new values, and the old values. 

Alog 50968 has a sketch of the procedure on how to update initial alignment references.

Images attached to this report
Comments related to this report
jenne.driggers@LIGO.ORG - 10:14, Thursday 30 January 2020 (54816)
Link

I've added rounding to the move_ARM_dev script, and I have added a try-except clause to the setEnd offsets scripts, so hopefully we won't see as many rounding SDF diffs in the future.  I'll test these on Tues.

H1 SQZ
sheila.dwyer@LIGO.ORG - posted 17:45, Friday 17 January 2020 - last comment - 10:45, Thursday 30 January 2020(54566)
~40 minutes of commissioning time for investigation of high CLF noise

We were out of observing for ~40 minutes this afternoon while Daniel and I measured the spectrum of the DCPDs up to 4MHz.  The goal of this was to see if it is plausible that noise from the interferometer (laser) around 3MHz is beating with the coherent locking field (at 3.125 MHz) and downconverting to create the noise we see when we have a more power in the coherent locking field.  Indeed, there is a lot of noise at high frequencies.  Calibrated plots coming soon.  

Comments related to this report
sheila.dwyer@LIGO.ORG - 11:45, Wednesday 22 January 2020 (54649)
Link

Here is a plot of the data taken from the DCPDs up to 4MHz.  I've removed the 20dB of gain and the poles at 265kHz and 290kHz from D1700376 in this plot.  This was measured with our usual darm offset, restuling in 10mA on each of the DCPDs (we used one of the single PD outputs from D1700376).  We tried to repeat this measurement with a diode set up in the AS air path yesterday, 54636, but the 3.125MHz peak was only 20dB above the noise level, so we weren't able to see any of the other noise apparent in this measurement.  

Non-image files attached to this comment
lee.mcculler@LIGO.ORG - 13:20, Wednesday 22 January 2020 (54651)
Link

Thanks, this is useful for ongoing CLF work.

For reference, Koji's measurements of the transimpedance are below. You can see that the rolloff flattens a bit in the MHz, so I'm less certain how real the bump is.

https://nodus.ligo.caltech.edu:8081/OMC_Lab/236

https://nodus.ligo.caltech.edu:8081/OMC_Lab/235

does your RF equipment have the ability to make a decently long cross correlation? That is surely what we need if we can conveniently get equipment to do it. Alternatively, you may be able to take spectra simultaneously in a sum and null output configuration, and then subtract them. It won't be as clean as xcorr, but it will show excess in a way that is less succeptible to systematic errors from inverting the PD response. Sum can be picked off from the SQZ chassis, and null just needs the phase shift before an RF splitter used in reverse (depending on the phase convention of the splitter).

Update, I remembered that I had acquired the LISO model and fit it in IIRrational for just these kinds of occasions. These fits should be decent up to 10MHz where the simulation cut off.

 

scipy ZPK notation:

(array([-1.09367517e+06+9.16935186e+04j, -1.09367517e+06-9.16935186e+04j,
       -4.54321270e+01+3.94631525e-01j, -4.54321270e+01-3.94631525e-01j,
       -2.85835003e+07+0.00000000e+00j]), array([-1.12584306e+07+1.59926553e+07j, -1.12584306e+07-1.59926553e+07j,
       -3.11667017e+07+1.49827313e+08j, -3.11667017e+07-1.49827313e+08j,
       -4.41594538e+07+5.59042545e+07j, -4.41594538e+07-5.59042545e+07j,
       -1.51046460e+07+2.52263715e+07j, -1.51046460e+07-2.52263715e+07j,
       -1.02822684e+05+0.00000000e+00j, -9.54273138e+04+0.00000000e+00j,
       -5.08417603e+02+0.00000000e+00j, -4.91824766e+02+0.00000000e+00j]), 2.71124765615596e+56)

foton notation:
ZPK([
  -174063.80969071676 + 14593.476738924443*i; -174063.80969071676 - 14593.476738924443*i;
  -7.2307475830315395 + 0.06280755795247621*i; -7.2307475830315395 - 0.06280755795247621*i;
  -4549205.365087142;
],[
  -1791834.8749338891 + 2545310.1382306265*i; -1791834.8749338891 - 2545310.1382306265*i;
  -4960334.630691198 + 23845757.522465646*i; -4960334.630691198 - 23845757.522465646*i;
  -7028195.359231514 + 8897438.443450466*i; -7028195.359231514 - 8897438.443450466*i;
  -2403979.0673290133 + 4014901.7200727463*i; -2403979.0673290133 - 4014901.7200727463*i;
  -16364.738450407038; -15187.728699344743;
  -80.91717459920993; -78.27634271397135;
], 2.71124765615596e+56, "f")

 

Attached are the fits and the output of the LISO model. I think the model differs a touch from Koji's measurements on the exact 3MHz cutoff frequency.

 

 

Images attached to this comment
Non-image files attached to this comment
sheila.dwyer@LIGO.ORG - 12:06, Monday 27 January 2020 (54753)
Link

Here is a plot (and the data used to make it) of the DCPD output measured with the analyzer in noise mode.  The first set of data (in the original log above) were taken in spectrum mode.  The dark noise in this new plot was measured durring Friday's EQ in Turkey, the "squeezer blocked" trace was taken durring the commisioning time Thursday (54681).   These are calibrated using the filters in D1700376 and Lee's estimate of the OMC DCPD transimpedance above.  Both spectra were taken with 30Hz resolution bandwidth and 3Hz video bandwidth.  A potential problem with this measurement could be that the squeezer came unlocked and the beam diverter closed partway through the measurement, although that didn't seem to have an impact on the spectrum here.  

It does seem suspicous that the quadrature difference, which should represent noise coming from the interferometer light, has a spectrum so similar to the dark noise. 

Non-image files attached to this comment
lee.mcculler@LIGO.ORG - 13:35, Monday 27 January 2020 (54756)SQZ
Link

This appears qualitatively a bit different than the post-demodulation measurement of the spectrum at LLO50307. There the blocked and dark noise ASD's changed by a factor of about 1.5. This appears to be substantially less than that at 3.125MHz.

sheila.dwyer@LIGO.ORG - 10:45, Thursday 30 January 2020 (54778)
Link

Here is one more plot of the DCPD spectrum up to high frequency, again.  In the original version of the attached plot in 54753  I made two mistakes in the calibration, which are fixed here..

  • The field on the DCPDs could be written as E_carrier +E_clf + E_am where E_am is am sidebands from the interferometer at audio frequencies around 3.125MHz.  The amplitude noise spectrum we measure on the DCPD is E_carrier*E_am while the term that could cause audio frequency noise by downconverting with the CLF is E_clf*E_am  The requirement for the amplitude noise around 3MHz is that the ASD of the photocurrent at 3MHz should be smaller than our audio frequency photocurrent asd*abs(E_carrier/E_clf)  In other words, the amplitude noise requirement around the CLF (and RLF) fields is less stringent than that at DC by the amplitude ratio of the clf to carrier light.
  • With 20mA total on the DCPDs, our shot noise limited sensitivity on each individual diode is 6e-11A/rtHz, without squeezing. 
  • We have been running with 5uW CLF injected into the OPO, and about -29dBm of RF power at the 3.125MHz demodulator since Nov 26th, before that we used -19dBm.  These powers are measured after the 20dB of gain in D1700376. This means we get 10uW of RF power out of the transimpendance amp, which is 92uA of photo current from the beat note of the 3MHz sideband with the DC power (20mA, 23mW). This means that we were using about 0.5uW of CLF on the DCPDs for the first part of O3, when we had noice from the CLF just below DARM.  Edit: The filter cavity design document T1800447 states on page 24 that there will be 10uW of CLF and RLF combined on the DCPDs OMC, which means about 0.1uW on the DCPDs, so this is similar to our current operating power. 
  • This means that to determine if ampltude noise down-converted by the CLF can explain the observed CLF noise, we would need to measure the spectrum of the DCPDs a factor of a few below 1.7e-8A/rtHz on a single diode.  To allow for 20 times more CLF power reaching the DCPDs with the filter cavity, we'd need to measure noise below 3e-9A/rtHz. 

The attached plot shows, in addition to the dark noise and locked spectrum, the level of amplitude noise which I think would be needed to create downconverted noise about equal to the current shot noise limited sensitivity.  One conclusion is that the dark noise of the DCPDs at 3MHz is too high for us to measure the level of amplitude noise that we need to measure to be sure that we can turn up the CLF power to the level required for the filter cavity controls. However, the difference between the in lock and the dark noise spectrum suggests that the current level of amplitude noise is well above this level, such that it should be dominating the noise in DARM.  So something seems to be wrong either with the measurement or with my projections.

One could worry that there might be significant variation between the individual transimpednce amplifiers at 3MHz.  We have a measurement made at 3.12MHz with the installed amplifier: 47540  which is roughly consistent with the one that Koji measured and Lee's fit above.  Another worry could be that we are running with a different transimpedance than these measurements were taken with, but we are running in high Z which is 400 Ohms at DC according to D060572, My plot of Lee's fit above gives a DC transimpedance of 200 Ohms, but it is ~220 Ohms at 3.125 MHz, so I think it is close enough.

 

Non-image files attached to this comment
LHO VE
chandra.romel@LIGO.ORG - posted 14:13, Friday 10 January 2020 - last comment - 15:14, Thursday 30 January 2020(54409)
possible air leak at EX

While RGA manufacturer was on site testing Labview-based RGA software, we noticed a significant AMU 28 peak at EX, towering water signature, suggesting an air leak. The total pressure is 1.9e-9 Torr and the trend is relatively flat, so no urgent concern. I suspect this is due to the failed annulus ion pump on GV20. We may have an inner o-ring leak on GV20 in addition to diffusion through o-rings.

AIP has been off for over a week as EX has been inaccessable due to tumbleweed blockages.

EY scan is also attached for comparison.

Non-image files attached to this report
20200110_Xend_analog_SEM_GV20_AIP_failure_1161V.pdf
20200110_Xend_analog_SEM_1000V.pdf
Comments related to this report
chandra.romel@LIGO.ORG - 14:19, Friday 10 January 2020 (54411)
Link

90 day pressure trends at EX and EY attached (log scale).

Images attached to this comment
chandra.romel@LIGO.ORG - 15:14, Thursday 30 January 2020 (54821)
Link

There is a typo in file name of original alog entry. The file name with 1000 V should be EY (not EX).

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