15:58PDT

Jeff K in the control room wants to take a DARM loop open gain and correct the calibration. Will wait to go into science mode. Handing of to Travis.

LLO was down at the beginning but came up during the injections. I did most of what I had hoped to do in the first round.

22:09UTC H1 is in science mode:

• The OIB was switched to Undisturbed

• Robert is going to destinations down the Y-arm where shakers will eventually be set up to do some "banging". He will record the time of his actions and the glitches can also be observed by the Detcharrians (spelling?)

• Aaaaaaaaannddd LOCKLOSS @ 22:18 RATS!

After much diddling with PR's and SR's while swinging them and watching camera images and dataviewer I finally came to my happy place with the alignments!

• 13:00 FINALLY got DRMI locked. It kept locking on the wrong mode. Trial and error landed me a manual pitch adjustment of PRM. BINGO.

• 13:08 RESONANCE

• 13:20 After much cautiousness, Locked at LSC_FF about 56Mpc. 

Robert Schofield is here and looking to do some PEM injections. He'll be going into the LVEA.  There seems to be a  strange disturbance in the Force that we can't explain. (see attached screenshot)

I spoke to Joe Hanson at LLO. At 20:30UTC they were locked on RF and were looking to move forward to DC Readout. I informed him as to our status and the testing that Robert was about to do for the next 1.5 hours or so.

For now.....life is good!

IFO locking difficulties continue:

• I re-checked initial alignment from "the ground up" just to review the state of everything else. Green looked good in both arms. PRM_ALIGN seemed to have gone well. I did improve the alignment on PR3 slightly. I then moved to MICH_DARK_LOCKED which seemed to converge nicely. It needed a little touching but at the outset always seemed to have some movement to it. I then moved on to SRC_ALIGN, which is where TJ handed off to me.

• Spent some time on the phone with Sheila trying to get the SRC alignment back to quasi-nominal. I got the spot bright and as round as I could get it. Increasing the laser power to 10W made the chore easier to deal with. It did lock but the stability was never resolved.

• I took a chance at moving forward to the DRMI_LOCKED state to see what would break. As I suspected by all of the swinging going on in the intial alignment, there was no glory.

• I then reverted back to looking at the PRM_ALIGN and saw that the alignment wasn't to good. Working on that now. Sheila will be in this afternoon. Fun.

As TJ mentioned in a earlier post there is an excitation showing at ETMX with 5-6 Testpoints occupied with some kind of business. We don't know what this is about and we really hope it isn't a contributing factor to our locking woes.  

I'm considering killing them if no one owns them.

Still no locking for my shift. I talked to Sheila for a bit and it seems that when the ISC_LOCK guardian was getting stuck in LOCK_DRMI_1F asking you to adjust by hand, it was only in a PRMI configuration and SRM was misaligned somehow(perhaps related to what I was seeing during IA). I moved SRM around for a bit and brought it back to some old values but still nothing.

Ed will have to finish up the mess I made for him.

model restarts logged for Fri 12/Jun/2015
2015_06_12 23:27 h1fw1*

* = unexpected restart

I took over for Travis as the interferometer was locking DRMI, shortly after I had to damp ETMY and ITMX bounce and roll modes. It then made it to BOUNCE_VIOLIN_MODE_DAMPING before it broke. After recovery, it got stuck on LOCK_DRMI_1F for a long time, much longer than usual (25min is where I would give up) . I have heard this could be from a bad alignment so I did a quick initial alignment with no issues and then made it a few times to REFL_TRANS/RESONANCE before it broke lock.

Again LOCK_DRMI_1F took a long time so I did another initial alignment. This time, I struggled keeping the ALS locked. It would all seem good and then one of them would catch a flurry of large modes and then recover back to a steady power above 1. When I limped through IA to SRC_ALIGN, Guardian said that it was locked and it was not. This happens some times and is normally an easy fix but I couldn't make it work well at all, it was constantly moving around. I eventually got something that was round(ish) but pretty wavey and tried to move on. Made it to LOCK_DRMI_1F and it asked that I adjust it by hand, which is also not working.

That's the rundown of my shift so far, let's hope it improves.

Looks like an excitation got left on for H1SUSETMX. I saw it on the CDS Overview when I arrived, there are 6 test points running on it right now. I don't see anything in the alog about this being here intentionally.

Times UTC

5:13 Intent bit set to undisturbed.  Note: calibration may have changed due to EY ESD issues.

5:18 Lockloss.

6:34 Intent bit set to undisturbed.

6:49 Lockloss.

Winds have calmed down since the beginning of the shift.  Now a breezy 10-20 MPH.

Richard, Evan

Summary

It appears that the EY ESD bias was stuck at −430 V ever since the installation of the low-voltage driver in May. It became unstuck on 11 June, when Richard reset the driver.

Since we have always requested a positive bias for EY in the digital system (using SUS-ETMY_L3_LOCK_BIAS), this means that the reset on 11 June flipped the sign of the EY ESD actuation, causing the transition of DARM from EX to EY to fail (as TJ found).

To fix the transition, the EY bias is now requested to be negative in the digital system, thereby restoring the sign (but not the magnitude) of the true analog bias that we have had since 22 May. Of course, if the magnitude of the L3 actuation has changed, this will affect the accuracy of the calibration in the region dominated by the control signal.

Details

First, let us enumerate some of the mysteries surrounding the EY ESD:

1. After the low-voltage driver was installed (i.e., after 2015-05-22), we found that we had to flip the sign of the L3 actuation from positive to negative. This is despite the fact that both the low-voltage driver and the high-range driver supposedly have positive polarity at dc (so we should not expect to have to compensate for an analog sign flip).
2. After the low-voltage driver was installed, we found that the dc actuation strength of EY L3 was 50 times weaker than EX L3. We expect only a factor of 20×1.25 = 25. The factor of 20 comes from the difference in dc gain between the high-range driver and the low-noise driver (40 V/V versus 2 V/V). The factor of 1.25 is what Kiwamu had previously found necessary to match the dc strengths of EX L3 and EY L3 when they were both driven by the high-range drivers.
3. After the low-voltage driver was installed, the analog readbacks for the high-range driver (bias line and 4 quadrants) were stuck at −15000 ct.
4. After Richard reset the high-range EY driver for the charge measurements (2015-06-11, circa 21:00:00 UTC), there has not been a successful transition of DARM from EX to EY (although there have been only four trials, according to the summary pages).

We hypothesize that mysteries (1), (3), and (4) are explained by the EY ESD bias being stuck at −430 V between 2015-05-22 and 2015-06-11, and the driver's readbacks being nonresponsive. Mystery 2 is still unsolved.

When Richard went to EY on the 11th, he found the high-range driver putting out −430 V on all five lines, and the driver's analog readbacks were frozen at −15000 ct or so. According to him, this is a known failure mode of the driver's microcontroller. After he reset the driver, the analog readbacks became functional again.

The attached plot shows a trend of the analog readback of the EY ESD bias. It is stuck at about −15000 ct from 2015-05-22 (when the low-voltage driver installation was finished) to 2016-06-11 21:00:00ish UTC (when Richard reset the driver). The natural conclusion from this is that the EY ESD bias has been railed at −430 V between these two dates (even though we thought we were giving +380 V of bias).

I flipped the requested bias so that it is now (I think) −380 V, which is the most negative bias that can be requested from the driver when it is operating properly. I was able to transition control of DARM from EX to EY by hand following the steps in the guardian.

No luck locking so far.  Winds are an issue once again, 20+ MPH with gusts over 40 MPH.  Commissioners may have discovered an issue with the EY ESD which could have been partially to blame for the lack of locks in the past day.  Talked to Gary in the LLO CR again and let him know we are in for another tough night.

We had four known reasons for having difficulty locking today, one is an unsolved mystery that might be hurting us more often than we realize.

• The BS limiter was off durring DRMI lock acquisition, this is turned on and off by guardian.  I've attached a screenshot of the gaurdian log.  The code should have returned true imediately after having turned off the limiter, and proceeded onto the next state, however, it ran the LOCK_DRMI_1F run again.  The requested state at this time was DRMI_1F_OFFLOADED, which means that this guardian should have moved onto the next state.  Is there a way to search the Guardian logs to see if we have had other instances of this?
  • we have seen this behavoir in the past, and Jamie suggested that this could have been because the state LOCK_DRMI_1F was requested.  I know that was not the issue today, but I changed the state so that it is no longer a requestable state anyway, since it should never be requested.
• The roll mode damping for ETMY was switched off at the output.  All the roll mode damping settings are now enforced by the guardian, using ezca.get_LIGOFilter().only_on.  

I reloaded both ISC_DRMI and ISC_LOCK guardians today, to incorporate these changes.  

• We had difficulty transitioning to ETMY ESD, evan is writting an alog about what we think is the solution
• Now the winds are quite high, the forecast says they will die down around 1 am.  

Good luck TJ!

A 6.0mag EQ occurring in Tonga, 8700km distance is a better candidate than the 5.7 EQ in Miyako Japan (7400km) alog 19074, I looked at yesterday for evaluating Terramon.  Slightly further away but enough larger and it makes all the difference.  With the 5.7 EQ, I couldn't be sure there was anything on the seismos, the predictor estimated a velocity of 1.9um/sec for the R-wave.  For the 6.0 EQ, the estimate is 5.

The arrival at the site is clear on the ground STS2--see attached.  I've marked the 3 times from the predictor with thin lines and we clearly see the arrivals.  The P-wave arrival estimate is very good; the plot is 40 minutes long.  The S-wave arrival is 'late' tens of seconds and the surface wave arrives more than 5 minutes sooner than predicted.  These channels should all be calibrated in nm/sec

The second plot shows some GS-13 channels on the BS ISI stage2 and an IFO red power showing if the IFO is fully locked.  The Surface (R-phase) arrival (last arrival) does clearly change the motion on the GS13s--I've marked the apparent arrival of the Surface wave on the plots--the thicker line.  The two fat portions of the GS-13 signal correspond to locked DRMI periods, beginning and middle of plot.  So what can I say...

1) The arrival of this P-wave may have brocken the DRMI although it broke ~20+ seconds after arrival prediction.

2) Clearly, the DRMI can hold lock during the arrival of the S-phase: it arrived some 50 seconds after the middle DRMI lock section began.

3) This IFO lock break was not caused by the surface wave arrival: it broke ~6 minutes before the obvious surface waves hit-marked at thick line.

4) The DRMI did not lock while the Surface Waves had the BS GS13s rung up although later looks show the DRMI may not be soley resposible for the GS13 ring up.  Still need to understand better what the IFO state does to the ISI.  I've chosen BS GS13s as they are not in loop so maybe the most vulnerable.

5) The arrival velocity prediction is within a factor of 2 of that observed.

Observation Bit: Commissioning 

08:00 – Take over from TJ – IFO not locked 
08:07 Christina & Karen – First cleaning at End-Y 
08:10 Betsy – Running ETM charging measurements at End-X
08:31 – Beam tube cleaning crew start work on X-Arm
08:50 Christina & Karen – First cleaning at End-Y
08:55 Richard – Cabling work at End-X for ETM charging measurement
09:06 Filiberto – Going to Mid-Y to get cables
09:15 Peter – Transition End-X building to Laser Safe. Lasers are on, tables & viewports secured
09:15 Betsy – Finished with ETM charging measurements
09:30 Filiberto – Back from Mid-Y
09:45 Richard – Back from End-X
09:50 Peter – Transition End-Y building to Laser Safe. Lasers are on, tables & viewports secured 
09:55 GRB Alert – IFO not Locked
09:58 Christina & Karen – Finished with first cleaning at both End Stations
10:43 Robert – Going to End-Y 
10:52 Snack Vendor on site to restock machines
11:20 Robert – Back from End-Y
11:37 Robert – Going to End-Y
11:54 Beam tube cleaning crew break for lunch
12:18 Robert – Back from End-Y
12:53 Beam tube cleaning crew working 
13:43 Beam tune cleaning crew finished 
15:34 Robert – Going beam tube enclosure near Mid-Y
15:55 Robert – Back from Mid-Y
16:05 Hand off to Travis

00:00 The ifo locked right before I came in. Wind speed is <20 mph. 90 mHz blend filter is used for BSC2.

           I noticed the BS oplev sum is saturated (> 80000 counts). Is this alright? It's been around this value for 10+ days.

01:55 There's a big bump at ~30 Hz that caused a big dip in the BNS range. SUS Oplev plots didn't show anything suspicious. The bump at this frequency happened through out the night, just not as big.

02:00 A 4.7 MAG earthquake in Ecuador shook PR3 a little and BNS range dropped slightly (from 61 Mpc to 60 Mpc), but that's all it did. No WD tripped. 

08:00 We've been locked for 8+ hours and still going strong at 61 Mpc! We had 5+ hours of coincidence with Livingston tonight. Handling the ifo to Jeff B.

Dan, Travis

Tonight during our long lock we measured the decay time constant of the ITMX bounce mode.  At 10:10 UTC we set the intent bit to "I solemnly swear I am up to no good" and flipped the sign on the ITMX_M0_DARM_DAMP_V filter bank and let the bounce mode ring up until it was about 3e-14 m/rt[Hz] in the DARM spectrum.  Then, we zeroed the damping gain and let the mode slowly decay over the next few hours.

We measured the mode's Q by fitting the decay curve in two different datasets.  The first dataset is the 16Hz-sampled output of Sheila's new RMS monitors; the ITMX bandpass filter is a 4th-order butterworth with corner frequencies of 9.83 and 9.87Hz (the mode frequency is 9.848Hz, +/- 0.001 Hz).  This data was lowpassed at 1Hz and fit with an exponential curve.

For the second dataset I followed Koji's demodulation recipe from the OMC 'beacon' measurement.  I collected 20 seconds of DELTAL_EXTERNAL_DQ data, every 200 seconds; bandpassed at 9 and 12Hz, demodulated at 9.484Hz, and lowpassed at 2Hz; and collected the median value of the sum of the squares of the demod products.  Some data were neglected on the edges of the 20-sec segment to avoid filter transients.  These every-200-sec datapoints were fit with an exponential curve.

Results attached; the two methods give different results for Q:

RMS channel: 594,000

Demodulated DARM_ERR: 402,000

I fiddled with the data collection parameters and filtering parameters for both fits, but the results were robust.  When varying parameters for each method the results for Q were repeatable within +/- 2,000, this gives some sense of the lower limit on uncertainty of the measurement.  (The discrepancy between the two methods gives a sense of the upper limit...)  Given a choice between the two I think I trust the RMS channel more, the demod path has more moving parts and there could be a subtlety in the filtering that I am overlooking.  The code is attached.