Displaying reports 64961-64980 of 83394.Go to page Start 3245 3246 3247 3248 3249 3250 3251 3252 3253 End
Reports until 02:01, Saturday 06 June 2015
LHO General
corey.gray@LIGO.ORG - posted 02:01, Saturday 06 June 2015 (18925)
First 2hrs of OWL Shift Status

H1 Status:

Seismically quiet and winds are hovering at 10mph or below.  TJ handed off a 24W H1 with range hovering between 61-69Mpc (but with glitches every ~30min).  The latest glitch at around 12:55am (7:55utc) caused a noticeable drop in the range, but the range is now tightened up to a flatter trend between 61-63Mpc.  I haven't noticed anything noisier on our FOMs to warrant the drop in range, but it does look a little more stable/steady.

Double Coincidence:

L1 has also come back and I chatted briefly with Will & Adam.  They said their locks have generally been lasting about ~5hrs.  At any rate after our step down in range, H1 & L1 are double coincident at about 62Mpc.

Misc:

EY VEA lights still on.  (I shut off all the lights I can shut off here in the corner station for the quieter weekend.)

H1 ISC
stefan.ballmer@LIGO.ORG - posted 22:46, Friday 05 June 2015 - last comment - 12:11, Saturday 06 June 2015(18923)
Back to 23W, ESD_X switched off - 66Mpc - (and yes, back in science mode for the night)
Evan, Kiwamu, Stefan (WP 5252)

We did a couple of tunings for 2 hours tonight during the time when LLO was down. This resulted in a inspiral range of 66 Mpc.

(ASC SRC1 yaw)
First, we tried powering up the PSL power from 17 W to 23 W to see what optics ran away. We confirmed that SRM was the one who ran away in yaw through the actuation of the ASC SRC1 loop as we went to 23 W. We searched for a signal which may represent this run-away motion of SRM. It seemed that the best choice was AS_A_36_I. Therefore we mixed this signal to the existing AS_B_36_I and AS_36_Q. Right now the SRC1 yaw signal is derived by -0.6 x ASA36I + 0.3 x ASA36Q + 0.3 ASB36I.
So far it kept holding SRC without a run-away issue on a time scale of 2 hour. This change is already reflected in both ISC_LOCK and ISC_DRMI guardians. Attached is a plot with the AS 36 YAW error signals during the tuning phase and first 2h of stable locking at 23W.

(AS36 whitening gain)
When we were at 23 W, we noticed that a few rf segments of both AS_36_A and _B saturated. So we decided to decrease the whitening gain from 24 dB to 21 dB. As a compensation factor we put a gain of 1.4 in the signal conditioning digital filters (i.e. H1:ASC-AS_A(B)_RF36_I1(Q)_GAIN). In this way we avoided updating all the ASC loop gains associated with these signals. This seemed to be fine for the locking sequence as well. So we will leave them in this new whitening gain configuration. We updated the SDF accordingly.

(Switching off ETMX ESD)
Evan forced us to study the effect of the ETMX ESD bias. Evan will post a detailed alog later. We remotely switched off the ETMX ESD and saw an improvement in frequency range from 40 to 100 Hz by a few 10%.

(Calibration correction with Pcal Y)
At the beginning the range went above 70 Mpc and therefore we started checking the calibration. According to the Pcal Y line at 540 Hz, the optical gain was too low by 4% compared with the peak height from this morning -- this underestimated the displacement and hence too-high inspiral range. We then adjusted the optical gain in the OMC error path and now the Pcal line agrees with the one from this morning. So the calibration is good.

(An accidental lockloss)
At around 2015-06-06 3:21 UTC, we accidentally lost the lock due to a senior LIGO fellow mistakenly pressing a wrong button during the high power study. This was the only lockloss we had in the past 10 hours or so.
Images attached to this report
Comments related to this report
evan.hall@LIGO.ORG - 23:10, Friday 05 June 2015 (18924)

As for the EX ESD, during each lock we ramp down the bias on EX from 380 V to 0 V, after we've transitioned control of darm to EY.

We have not verified that this is in fact the optimal bias for minimizing the effect of the charge on EX; i.e., DAC noise and driver noise may still produce motion of the optic even if the applied bias voltage is 0 V.

Therefore, I spent 10 minutes tonight investigating this by trying a few different negative bias voltages with the IFO at 15 W. This didn't seem to really have an effect. However, inactivating the ESD driver did (see attachment).

At 24 W, the improvement is more noticeable. The attached png shows the comparison between tonight's spectrum and our previous best. The previous best was taken with the old EY ESD configuration, but we've seen over the past week that the new driver and the recalibration have not changed the shape or magnitude of the control noise, so the comparison is fair.

Also attached are some coherences with the new DARM spectrtum. We can see that SRCL has high coherence between 15 and 70 Hz (and also between 2 and 6 kHz... strange), and there is nonnegligible coherence with intensity from 100 to 400 Hz (this will probably be improved once Robert and Kiwamu continue their IMC WFS offset tuning).

If the EX driver does not come back on after lockloss and you cannot reset it using the EX ESD screen, then you toggle H1:ISC-EXTRA_X_BO_4 between 0 and 1 using caget.

Images attached to this comment
Non-image files attached to this comment
jameson.rollins@LIGO.ORG - 12:11, Saturday 06 June 2015 (18933)

66 Mpc!!!  You guys caught L1!  Very nice.

LHO General
thomas.shaffer@LIGO.ORG - posted 21:49, Friday 05 June 2015 (18922)
Ops Report

With the commissioning work done, the Intention Bit is set back to Undisturbed.

We are currently locked at LSC_FF.

H1 SUS
kiwamu.izumi@LIGO.ORG - posted 20:27, Friday 05 June 2015 (18921)
elliptic low pass enabled on SR2 longitudinal damping

WP 5251,

At around 2015-06-06 2:30-ish UTC, I enabled an elliptic low pass filter in the top stage longitudinal damping loop in the SR2 suspension, at FM10. This is something we meant to enable all the time (alog 18694) but somehow got disabled a couple of days ago for some reason. I updated the SDF accordingly. So fat the SR2 suspension looks behaving fine.

LHO General
thomas.shaffer@LIGO.ORG - posted 19:31, Friday 05 June 2015 (18920)
Ops Report

With LLO down, we have some work permits to take care of.

The work consists of: Stefan increasing the power back to 23W and Kiwamu enabling a low-pass filter in SUS SR2.

At 19:28pst the Intention Bit was switched to Comissioning to reflect the work being done.

H1 General
lisa.barsotti@LIGO.ORG - posted 18:22, Friday 05 June 2015 (18912)
Gravitational waves, come to us!
More seriously, since several people asked me how to have "real time" info about the status of the detectors, I advertize here 
 this monitor  that Peter Shawhan and Chad made, displaying basic detector status with ~30-45 seconds average latency:

https://ldas-jobs.ligo.caltech.edu/~pshawhan/gwistat/

Images attached to this report
H1 DetChar
kiwamu.izumi@LIGO.ORG - posted 18:01, Friday 05 June 2015 - last comment - 10:00, Tuesday 09 June 2015(18918)
unidentified DARM glitches

Stefan, Kiwamu,

In this morning, DARM had many numbers of glitches which were visible in the DARM spectrum as wide band noise. We looked at various channels to see what caused the glitches, but we were not able to identify them.

We would like to get some help from the detchar people. Could you guys please look for a cause of the DARM glitches ?

The lock stretch which had a high glitch rate is the one starting at 2015-06-05 17:17 -sh to 18:00 -ish UTC. I attach an example time series of the glitches shown in OMC-DCPD A and B. We know that some of the loud ones were so large that they saturated the ADCs of the OMC DCPD.

Note that in the same lock stretch, we changed the DARM offset multiple times which changed the amount of the carrier light resonating in OMC. We do not think our activity with the DARM offset caused the high glitch rate.

Images attached to this report
Comments related to this report
stefan.ballmer@LIGO.ORG - 18:04, Friday 05 June 2015 (18919)
Here is also a DARM spectrum and time series, as well as the summary page range graph. The glitches occur in the short science segment just before 18h.
Images attached to this comment
thomas.massinger@LIGO.ORG - 11:32, Saturday 06 June 2015 (18932)DetChar, ISC

We need to do some more thorough follow-up, but I can give some quick feedback that might give some hints. The initial signs seem to suggest that the problem might be due to input pointing glitches or alignment fluctuations in the PRC.

The loudest glitches in that short science segments were coincident with ASC-REFL_A_RF9_I_PIT_OUT_DQ, which looks like it was being used as the error signal for INP1 and PRC2 loops, feeding back onto IM4 and PR2. The corresponding YAW channel was also significant, but not quite as much so. We also saw ASC-REFL_B_RF9_I_PIT_OUT_DQ as somewhat significant, which looks like it was being used in both the INP1, INP2, and PRC2 loops and feeding back on IM4 and PR2.

kiwamu.izumi@LIGO.ORG - 10:00, Tuesday 09 June 2015 (19011)

So, we now start believing that these loud glitches were related to the cleaning activity on the X arm vacuum tube (alog 18992). Here I show glitch wave forms in time series from three glitch events (out of many) that were observed in this past Friday, 5th of June.

Typically the glitches were very fast and I am guessing that the glitch itself happens on a time scale of 10 ms or maybe less. Usually the OMC DC signals or the DARM error follows with a relatively slow oscillation with a period of roughly 100 msec which I believe is an impulse response of the DARM control. All the three events showed a power drop in the carrier light everywhere ( TRX, TRY and POP) indicating that the power recycling gain dropped simultaneously. For some reason POP_A_LF showed slower power drop which I do not understand. Also, in all three events that I looked at, the OMC DCPDs showed small fluctuation roughly 20 ms before the big transient happens.

 

1. 2015-06-05 17:49 UTC

(This one contains two glitch events apart only by roughly 200 msec)

2. 2015-06-05 15:51 UTC

3. 015-06-05 17:55 UTC

 

4. High passed version of glitch event 1

(all the time series are high-passed with zpk([0], [40], 1) ). You can see a glitchy behavior in REFL WFS (as reported by TJ) as well as TRX QPD  (and a little bit in TRY QPD).

Images attached to this comment
H1 CDS
david.barker@LIGO.ORG - posted 17:33, Friday 05 June 2015 (18917)
CDS overview MEDMs changed to show stuck DAQs

WP5250

I have changed the CDS STATE_WORD overview MEDM screens to show a red rectangle if any of the DAQ systems stop updating. If today's freeze up of the broadcaster were to re-occur, it should now show a red alert. I'm using the h1ioppsl0 GPS counter as the standard against which I compare the DAQ GPS counters. If they lag by 60 seconds the alert is shown.

H1 CDS
david.barker@LIGO.ORG - posted 17:12, Friday 05 June 2015 (18916)
order of alog entries

There has been some discussion on how alogs are ordered on the web page. Here is what I learned this afternoon after speaking with Ryan.

Each page displays 20 entries. These can be new entries made recently with no comments or new entries with recent comments, in which case they are listed in chronological order of the initial post.

If any of today's entries are comments to an old post (one which would normally not be displayed in the page) then the initial post is shown in today's page, along with every comment it has garnered including today's comment(s). These "promoted" entries are shown at the bottom of the page in chronological order of the initial posting.

For example, at the bottom of today's (Friday 05 June 2015) first page there are two old posts which were commented on recently, they are in the order: 

evan.hall@LIGO.ORG - posted 21:21, Thursday 04 June 2015 - last comment - 12:47, Friday 05 June 2015(18878)

kiwamu.izumi@LIGO.ORG - posted 11:16, Friday 29 May 2015 - last comment - 14:45, Friday 05 June 2015(18693)

Note the order of the initial post, not the order of the last comment.

Therefore the alog entry numbers can be out of sequence. Also some numbers may not appear at all if they were assigned to a draft entry which was subsquently abandoned.

H1 ISC
daniel.hoak@LIGO.ORG - posted 16:56, Friday 05 June 2015 (18915)
gouy phase separation for AS actuators, sensors

For some guidance regarding beam centering in HAM6, I post here the estimated Gouy phase for the optical elements between SR3 and the OMC.  The a la mode script that was used is attached, along with the parameters file which uses the best available positions of H1 optical elements in HAM6.  This is the same material that was posted in alog:14023, here I add information and SR2, SR3, and AS_C.

 

Optic / sensor Gouy phase (deg)
SR3 47
SR2 48
   
AS_C -171
   
OM1 109
OM2 -149
   
AS_A -78
AS_B 4
   
OM3 -119
   
OMC QPD A -95
OMC QPD B -80


From these results there's no obvious pairings of actuator --> sensor, except for OM1 --> AS_B and OM2 --> AS_A, which is essentially what we're using right now.  The OMC QPDs are degenerate, but we construct a waist basis for the OMC alignment, {OMC_A, OMC_B} --> {POS, ANG} using the known geometry of the OMC breadboard.

The plots attached show the beam propagation for the path from OM1 to AS_C, the AS WFS, and the OMC, respectively.  Note that these beam propagations are for a single-bounce beam from ITMX.  We know the mode from the full IFO is different (because the mode-matching into the OMC is different, between a single bounce and the full IFO), but it's not a large difference.

Anyways we shouldn't rely on simulation, we should measure the sensing matrix from {SR3,SR2, OM1, OM2, OM3} --> {AS_A, AS_B, AS_C, OMCA, OMCB} and work out a control scheme.

The a la mode script and parameters file are attached.

Images attached to this report
Non-image files attached to this report
LHO General
cheryl.vorvick@LIGO.ORG - posted 15:49, Friday 05 June 2015 (18914)
Ops Day Summary:

Apollo finished the beam tube this afternoon.

No other site related activity to report.

 

IFO:

Short lock around 17UTC was very glitchy, and didn't last.

I helped the DRMI alignment when relocking and while it took about two hours and more than one attempt to get the IFO back to full lock, the current lock has been going for almost 3 hours.

Intent bit was engaged and alogged earlier.

Changes during this lock are that the OMC Dither was turned off and then on again.

SDF was red but now green.

Kiwamu has an approved work permit to enable a filter on SR2, which has glitched a few time during this lock.

Stefan has an approved work permit to try for 23W locks as soon as he has an opportunity.

LHO FMCS
bubba.gateley@LIGO.ORG - posted 15:47, Friday 05 June 2015 (18913)
Beam Tube Enclosure Joint Repair
Chris S.

Beginning 120 meters from the corner station on the X-Arm, 40 joints were cleaned and metal strips attached. 
Caulking still needs to be completed on those joints. 
LHO VE
bubba.gateley@LIGO.ORG - posted 15:27, Friday 05 June 2015 (18910)
Beam Tube Washing
Scott L. Ed P.

Cleaned 33.5 meters of tube ending 8.4 meters north of HNW-4-066. Cleaning crew left at noon, both feeling ill.

A total of 3297 meters of tube cleaned to date.
H1 GRD
cheryl.vorvick@LIGO.ORG - posted 15:17, Friday 05 June 2015 - last comment - 15:28, Friday 05 June 2015(18908)
SDF cleared - currently all green while the IFO is in a 17.7W lock

With help from Betsy and Corey, and confirmation from Kiwamu and Hugh's alog, I cleared the IMC-DOF offsets - confirmed as a change from Robert's work and working well.

I also turned the OMC-ASC_DITHER_MASTER off.

Comments related to this report
cheryl.vorvick@LIGO.ORG - 15:28, Friday 05 June 2015 (18911)

And then again...

Actually, Dan would like the OMC Dither enabled as a monitoring point, and maybe use the dither alignment, so the agreemeet with Kiwamu and Dan was that we'd turn the dither on, and acept it in the SDF.  

OMC Dither = ON is now acepted in SDF, and SDF overview is again all green.

LHO General
corey.gray@LIGO.ORG - posted 14:49, Friday 05 June 2015 - last comment - 15:22, Friday 05 June 2015(18907)
Why Are Alogs 18878 - 18886 Missing??

I don't see any of the alogs I posted last night.  I can see them if I search myself, and they show up, but they aren't showing up in the alog.  BUG!!!

Comments related to this report
evan.hall@LIGO.ORG - 15:22, Friday 05 June 2015 (18909)

I see yours show up on page 2. There have been a bunch of replies posted to various entires today, so the top-level entries get bumped up to the first page (even if they have a lower alog number than some of the top-level entries on the second page). I agree it is not a very straightforward behavior.

H1 SUS
kiwamu.izumi@LIGO.ORG - posted 11:16, Friday 29 May 2015 - last comment - 14:45, Friday 05 June 2015(18693)
SR2 saturates

Something is not healthy on SR2 suspension.

Recently we noticed that some DAC on SR2 suspension saturated intermittently at a rate of roughlu once per 10 minutes or so. At the begginig we thought this was due to some ISC feedback saturating some DACs when we lock the interferometer. However, it turned out that it saturates even when no ISC feedback is sent.

The attached is a one-hour trend of all the saturation motniors of the SR2 top stage actuators from the period when SR2 was aligned and damped without any ISC feedback signals yesterday. As seen in the plot, the RT and LF DACs saturated mutiple times. The LF saturated more frequently than the RF actuator. Looking at the suspension screen, Betsy and I found that the longitudinal dampig showed higher signal level at its output than every one else. It is on the order of 100 counts at the output. Betsy is currently checking the longitudinal damping loop by running a transfer function measurement.

Images attached to this report
Comments related to this report
betsy.weaver@LIGO.ORG - 11:25, Friday 29 May 2015 (18694)

I ran a damped L (longitudinal) loop TF which looks "healthy" when compared to previous TFs - so nothing agregious there.  However, we note that we do not have a lot of damping in any of the H1 HSTS L loops as observed from looking at the other HSTS L TFs.  Also the L loop output seems to be doing more work (higher numbers rolling through) than other L loops.  We started looking at filter diffs in the L loops and see that in some HSTSes we have the FM10 Ellip50 engaged.  We engaged this filter and see that the L loop output became much quieter (closer to zero).  Kiwamu wants to see if this will improve the saturations of SR2 and imprve locking.  Attached is a quick damped TF of SR2 M1 DAMP L with the FM10 engaged, as well as a screen snapshot.

Images attached to this comment
Non-image files attached to this comment
kiwamu.izumi@LIGO.ORG - 14:45, Friday 05 June 2015 (18906)

For some reason, the elliptic filter that we installed at FM10 of the longitudinal damping loop was taken out on 2015-June-2 18:00. SR2 seems to be saturating again. Sad.

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