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:

• trip of EY ESD driver at every unlock happening from the final low noise state (requiring a trip to the end station for resetting the driver);
• trip EX PUM whatchdog (not immediately recognized from the control room, also requiring a trip to the end station);
• some new which required some effort to get damped;

Some more details

• The improvement below 20 Hz in the sensitivity is entirely due to the cut-offs we added to the CHARD loops;
• Even after transitioning the BS M2 coil driver to low noise, and moving to POPAIR, we still have some coherence with MICH below 100 Hz. We tried to engage the MICH subtraction path, but we unlocked in doing so. Since unlocking from low noise costs us a trip to the end station, we didn't try harder..
• We closed the OMC REFL beam diverted;

Final IFO & Guardian state

• We promoted the SRCL 20 Hz UGF + cut-off in the Guardian, as it seems to work well;
• The transition to ETMY ESD low noise + DARM boost is still done by hand (it is written in the Guardian; we are just not brave to try it)
• The transition to BS low noise is also done by hand, and since it has failed at least once in the past, we decided not to engage it in this last lock
• Stage 2 ISI on BS is tripped..
• Sheila prepared some more cut-offs for the ASC DHARD loops, but we haven't tried those yet.

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

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:

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

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.  

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.

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.

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.

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.

In the continuing saga of the Ring Up of the BRS, I've turned off the damper. I turned it on yesterday thinking that 2 days was sufficient rest for the BRS to settle down, but Krisha reports that it probably needs more like 4-5 days, given current levels of excitement. It would be best if people avoided the end station, as the BRS is now completely uncontrolled.

The damper is controlled by a line of code that sets the variable TestData (or some variation of capitalization thereof). The normal line sets this equal to 2.5 - outvelocity. To disable there is a line immediately below that is commented out that sets TestData to just a constant (2.5). Uncomment this line and restart the code. Done.

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.

Laura, Josh, Andy, Joe, Detchar

We took a look at the 28 Mpc lock on 24th March to see if there was any evidence of arches that we have seen previously at LLO (for example LLO alog 17090).

The first attachement shows a histogram of the rate of glitches (omicron triggers) binned by the value of IMC-F at the same time. The plot looks pretty Gaussian, except for a few bins specifically between IMC-F values of -37.5 to -41.7 and -45.8 and -50. Between these values we see evidence of arches in DARM. The second attachment is a pdf file showing the arches in DARM lining up with values of IMC-F in the second bin. Here are links to many spectograms confirming the arches in the IMC-F bins outlined (spectrograms for IMC-F bin -37.5 to -41.7 / spectrograms for IMC-F bin -45.8 to -50). Each spectrogram time corresponds to a glitch as seen by omicron.

LLO has dramatically reduced the effect of these arches, see LLO alog 17191.

Also the value IMC-F has when these arches appear in DARM seems to drift, i.e. there does not appear to be a specific value of IMC-F which produces the arches (this is evident in the second attachement). This is not what we have seen at LLO, does anyone know what could be causing this?