J. Kissel, K. Izumi, S. Karki, D. Tuyenbayev, R. Savage

I attach a picture of the whiteboard where we've sketched out our plan for the week. We've gone through T1500443, taken off items that we've already managed to capture before this week, and prioritized the remaining tasks accordingly.

Stay tuned for daily updates on progress.

J. Kissel, K. Izumi

At 16:02 UTC, we've taken the IFO down to begin calibration measurements.

On today's docket:
- Actuation function frequency dependence checks
    - UIM, PUM Coil Driver TFs
    - ESD LVLN Driver TFs
- Sensing function frequency dependence checks
    - OMC DCPD AA Chassis
    - OMC DCPD PreAmp (with single bounce IFO)

ALL TIMES IN UTC

Science Mode Checklist: (beginning of shift)

• Guardian:  NOMINAL_LOW_NOISE

• Inspiral Range: 62Mpc

• LVEA Sweep: N/A

• Ops Overview: Clean and Green (except for the beam diverter caveat)

• CDS Overview: Green except for Cal injections

• SDF Overview: All Diffs cleared except for  SUSPRM, OMC  and CALCS.

• SYS DIAG:  the usual BRS message

• Calibration Lines: Calibrations are running.

• ODC Master Observation Ready Bit: GREEN

• Observation Intent Bit: UNDISTURBED

• Ops Observatory Mode: Observing

Activity Log:

• 12:10 EY .3µ Dust Alarm Major

• 12:21 EY .3µ Dust Alarm Major

• 12:22 Set the Observation mode to ‘Environment’ while the earthquake settles down

• 12:26 Christina on site

• 12:26 Muted annoying EY dust monitor alarm

• 12:45  Took ISC_LOCK to down while Z-axis settles. Incessant OMC DCPD saturation Verbal Alarm after Lockloss and OMC still flashing. I called Evan and he instructed me to slide the ‘OFFSET’ slider in the OMC CONTROL Screen to the left a bit until the flashing stops. Guardian will touch this again when it’s time for locking. Verbal Alarm for this should be addressed as it was sounding excessively for an innocuous event according to Evan.

LOCK LOG:

• 11:42 IFO Locked at NLN. Range ~62Mpc.

• 11:59 Observation Intent Bit and Observatory Mode set

• 12:07 Lockloss.  There appears to be a mag 5 earthquake in the North Pacific off the coast of Russia

• 12:08  Begin locking sequence

  • DRMI - may take a while. mag 5 quake N Pacific/Russia

    • DRMI 1F locked after 15 minutes but came unlocked. I’m pretty sure it was the earthquake now

• 12:32 DRMI LOCKED

• 12:32 Attempt to proceed failed

• 12:57 Begin sequence (EQ calming) we’ll shoot for DRMI for starters.

  • DRMI Locked 1F in about 2 minutes

• 13:02 Lockloss. Never made it to 3F.

• 13:03 Begin sequence

  • DRMI Locked 1 min

• 13:19 Locked at NOMINAL_LOW_NOISE. 62Mpc

• 13:28 Set OIB and OOM to Undisturbed/Observing

Shift Summary:

• Most of the night was spent commissioning to resolve a problem with stability at “high” power.

• locking resumed at 11:42UTC and went well until an earthquake off the coast of Russia shook things up for about 1.5 hours.

• The wind stayed down all night and another good lock was achieved and hopefully will hold as I hand off to Jeff B. Only 1 ETMY saturation noted during this last lock, so far.

13:28UTC OIB and OOM set to Undisturbed/Observing

ALL TIMES IN UTC

Science Mode Checklist:

• Guardian:  NOMINAL_LOW_NOISE

• Inspiral Range: 62Mpc

• LVEA Sweep: N/A

• Ops Overview: Clean and Green (except for the beam diverter caveat)

• CDS Overview: Green except for Cal injections

• SDF Overview: All Diffs cleared except for  SUSPRM, OMC and CALCS.

• SYS DIAG:  the usual BRS message

• Calibration Lines: Calibrations are running.

• ODC Master Observation Ready Bit: GREEN

• Observation Intent Bit: UNDISTURBED

• Ops Observatory Mode: Observing

Activity Log:

• 11:42  got the “go ahead” to go to NOMINAL_LOW_NOISE. Range -60Mpc
• 11:59 Observation Intent Bit and Observatory Mode set
• 11:50 Evan has cleared most of the diffs in SDF Overview. PRM will stay red due to script workaround for current problem with LL OSEM signal and OMC will stay red because he wasn’t sure that the changes effected were meant to be permanent.

Sheila, Evan

We looked again at the situation with the 45 MHz REFL WFSs, which are used as sensors for the PR3 ASC loop. In the end, we didn't implement any changes to the sensors or the associated loops.

We were motivated by the following:

1. The current demod phases for these WFSs simply do not make sense; we expect that they should be similar (since the analog delays should be fairly well matched), but instead they are scattered by 100+ degrees.
2. The cHard and PR3 loops are strongly cross-coupled. We would like to be able to turn up the gain of cHard without impressing extra motion from other optics into DARM. [20523, 20497]
3. Any perturbation in the PR3 seems to couple into the SRC loops. We already know that the SRM loop is quite delicate, and we would like to get rid of this coupling if possible.

We tried the following:

• We changed the demod phases of the 45 MHz REFL WFSs, and then closed the PR3 loops.
  • We chose phases so that cHard pitch appears entirely in the Q phase (thereby leaving I dominated mostly by PR3 motion, hopefully). This was done previously, but loop retuning was not investigated in detail. Also, the phases of A3, A4, B3, and B4 seem to need an extra 180° phase shift in order to produce correctly phased signals (see screenshot).
  • We then found that only REFL45B gave a sensible error signal in response to PR3 motion (both pitch and yaw), so we closed the loops around B only. Additionally, the required digital gain went from 2 ct/ct (with the old phasing) to 40 ct/ct, perhaps indicating that the "old" PR3 configuration is actually dominated by cHard motion.
• This seemed to produce a constellation of bad things:
  • The sideband buildups (POP18 and AS90) were slightly suboptimal (i.e., fuzzy and not maximized).
  • The soft loops reduced the recycling gain (to 36 W/W or so) when they came on.
  • Switching the SRM yaw loop input matrix elements at 3 W seemed to make POP90 worse.
• We tried using new trans QPD offsets for the soft loops, but this led to the familiar angular instability when going to 20+ W.
• We also tried to find a new SRM yaw matrix element, but this didn't work either.
• We also turned off the dc oplev coupling on SR3, since we didn't want the optic position to be dragged away by the ground.
• In the end, we simply reverted all the changes we made.

After that, we couldn't get to full power because of an oscillation that showed up in dHard pitch when going to 20+ W. (We've seen this before, and it seems to be distinct from the angular instability mentioned above.) To get around this, we had to slightly beef up the resonant gain that gets turned on in dHard pitch when the power is increased.

Also, there were some small maintenance tasks that we did:

• Improved the filter hygiene of the DC centering loops (there were some integrators that didn't have ac gain of 1, some low-pass filters that didn't have dc gain of 1, some filters with ambiguous names, etc.)
• Added an optional ISC_LOCK guardian state called REDUCE_MODULATION_DEPTH, which implements the 3 dB modulation depth reduction that Stefan and I have carried out before.

ALL TIMES IN UTC

On my arrival, Evan, Sheila and Dan on site (of course Jim also). Not really any wind to speak of (~10mph). Minor earthquake activity in the last couple of hours after about 5 hours of quiet. Everyone gone except for Evan.

Science Mode Checklist: (since beginning of shift)

• Guardian:  actively running lock sequence while commissioners are troubleshooting

• Inspiral Range: N/A

• LVEA Sweep: N/A

• Ops Overview: In flux due to commissioning work

• CDS Overview: mostly green except for the typical OVF errors and the Calibration Line Excitation

• SDF Overview: Diffs showing on: SUSPRM, SUSSR3, LSC, ASC, OMC, ISCEX & ISCEY. Others are ODCX, ODCY and CALCS.

• SYS DIAG:  the usual BRS message

• Calibration Lines: It appears that Calibrations Lines are running.

• ODC Master Observation Ready Bit: RED

• Observation Intent Bit: Commissioning

• Ops Observatory Mode: Commissioning

Activity Log:

• 7:00 Evan and Sheila continuing work on ASC.

• 7:32 ETMX Dust Monitor giving Invalid Alarm

• 8:08 Refreshed the Operating mode FOMs

• 9:32  ETMX Dust Monitor giving Invalid Alarm

• 10:52 Still working on ASC issues

Quiet night again.

IFO was locked when I arrived, but was knocked out by an earthquake.

Sheila and Evan have been working on ASC improvements since.

Lock loss where SRCL went first.

Guardian code issue stalled progress to Low Noise, now fixed.

ETMX PUM needed to be reset.

IFO has been locked for 2 hours and range is above 60MPC.

Currently in commissioning mode - Sudarshan, Sheila, and Evan are here.

Plot attached shows SRCL goes at -30 seconds, then PRCL goes at -12 seconds.

Lock Loss right after PRM saturation - lock loss plot shows an issue in SRCL came first, then PRCL responded, then lock loss

- plot attached shows PRM _M3_LOCK_L_OUTPUT 

--- signal changes directions at 17:46:14UTC

--- exceeds it's normal range at 17:46:17UTC

--- abrupt change of the signal at 17:46:22UTC

--- signal exceeds it's normal range (negative) at 17:46:25UTC, Lock Loss

Relocked:

- didn't make it through RF_DARM

Relocked:

- didn't make it through RF_DARM, and I tried to diagnose it, but couldn't, so put the IFO Mode to "unknown,"

Guardian Code issue, corrected:

- Sheila arrived and she diagnosed the problem - Guardian code was waiting for OMC_LOCK to be in "ready to hand off" but OMC wasn't ready.

- Sheila corrected the code so now it only looks at the two arms to see if they are ready.

LSC_LOCK was waiting for OMC to be ready, but OMC wasn't ready, so we cleared that and tried to go on t DARM_WFS and the IFO made some progress but then lost lock.

Relocked

- lost lock at DARM_WFS again - reason unknown.

ETMX Coil issue, corrected:

- after lock loss, ETMX coils died, Sheila went to EX to fix.

Back in Observing/Undisturbed Mode:

- ETMX fixed, relocking went well, and as of 20:36UTC Obs/Und Mode bit set.

NOTE: on the observatory mode screen

I used the UNKNOWN mode for locking issues (since the cause was unknown to me) and for the ETMX fix (because Corrective Maintenance just didn't seem to fit what was an equipment failure).

Sheila is driving down to EX to fix.

ETMX SUS screen doesn't seem to have any indicator that something's not OK.

Guardian error message: SUS ETMX saturation.

ER8 Day 6. No restarts reported.

Jim, Evan

We have grown tired of the glitching in the PRM M3 LL OSEM, so here is a script that ramps it off in full lock. It gets rid of the glitching and allows us to recover 60ish Mpc range.

Also included is a screenshot of the usual Euler/OSEM matrix for PRM.

Sudarshan reports that a PCal line was turned off sometime last night.  He is turning it back on at 17:53.

This is a follow up analysis of Robert's anthropogenic noise injections on August 12th. So far I don't see any convinving evidence that these activities were actually coupled into DARM. There were couple of injections ("human in optics lab" and "jumping in the change room") that seemed to coincide with DARM noise around 20-100Hz but it was unclear whether those injections were actually causing the noise. The noise *blobs* started prior to the injection and the PEM seismic sensor only coincided with one of them. Plus I would expect to see a coupling at much lower frequency if human jumping up and down the change room actually injects noise into DARM.

Note that the first injection time (15:05) is still unconfirmed. The time in the original table was wrong.

Kiwamu, Hang

We did an estimation of the beam position on test masses based on the a2l gains that gave us best decoupling.

The result was shown in the first image attached. The blue line indicated the boundary of L3 and the red spot the position of the beam on the test mass. It seemed that the beams were <~1 cm off center.

===================================================================================================================================

In case that you are interested in how we obtain the results:

The basic idea is to excite the pitch (yaw) motion of L2 stage, and let this excitation go through both

1): the L2->L3 P2P (Y2Y) path, and

2): L2->L2 P2L, and then L2->L3 L2L and L2P.

The ratio of L3's L over L3's P will then give us the vertical position of the beam on test masses. See the second picture for a graphic representation.

===================================================================================================================================

The code to re-run this analysis is available at:

/opt/rtcds/userapps/release/isc/h1/scripts/a2l

You can do the analysis by entering

./run_GrabBeamSpot.sh

in the command line