【 Jenne, David, Matt, Evan 】

We spent some time trying out 2 W interferometer operation with lower modulation depths for the 9 MHz and 45 MHz sidebands. Nominally, the modulation depths are 0.22 rad for 9 MHz and 0.27 rad for 45 MHz.

I have attached scripts which can be used to step the modulation depths up or down using the Siggtronics EOM drivers in the PSL. These will adjust all digital photodiode gains appropriately, so that the interferometer stays locked. The only thing needing manual adjustment is the CARM gain.

In this way we were able to reduce the 9 MHz modulation depth by 6 dB without issue.

The interferometer became noticeably less stable with 4 dB of reduction of the 45 MHz modulation depth. In particular, the dHard loop gains seemed to increase, causing a loss of gain in the DARM loop around 20 Hz. The MICH and SRCL loop shapes did not change. Lowering the dHard loop gains by a factor of 2 enabled us to reduce the modulation depth by 6 dB compared to the nominal. There was also noticeable wobbling in the PRM yaw pointing loop control signal (maybe motion impressed by the 45 MHz PR3 loop?). If we want to run with lower 45 MHz modulation depth, a campaign of ASC loop measurement is probably a prerequisite.

After restoring the AOM driver back to its original power cable, the ISS would not lock and kept oscillating.
The servo control voltage kept varying between ~0.2V and ~0.6V, meaning that the amount of diffracted light
requested was varying from one extreme to another.  I looked at the diffracted spot and all I noticed was the
intensity of the diffracted order seemed fairly constant.

    The input RF was measured with an oscilloscope to be ~410 mVrms, which as I recall is not enough.  I opened
up the AOM driver and the +15V voltage regulator was no longer supplying 15V.

    The spare AOM driver has been installed for the time being.

    Whilst hardware-wise things are in place, I will have to wait until the computer maintenance tasks are
completed before being able to test the ISS again.

    The external laser shutter - ie the one located in the high power oscillator - is closed for now, and
the watchdogs have been turned off.

I nominally energize the turbo controllers during Tuesday maintenance periods so as to charge the external batteries.  Today I found them still energized from last week.  This means there have been four additional fans running in the LVEA during this time as well as any associated EMI-noisy supplies -> I de-energized them this morning.

J. Kissel

I've reconciled what changes were made last night during commissioning, and begun bringing SEI and SUS to safe for this morning's timing upgrade. I'm leaving HAM23 SEI and SUS up and running because Peter's finishing up commissioning the ISS in the PSL. There are several changes in the PSL ISS SDF system (with respect to the down.snap) as a result of his commissioning; we'll make sure those are accepted before we upgrade the PSL front-end timing.

There were only three things to reconcile -
- some new(?) damping filters were turned on in the QPD portion the SUSETMYPI model (DAMP_MODES 3 and 4), 
- an ALS-C_COMM_PLL_PRESET was set at "No" instead of "Low" last night at Jul 19 00:13 PDT, and
- a PSL-ISS_TR_LIMIT set to 1000 in the LSC model. Since this was set at Jul 18 22:48 PDT (so I'm assuming this is *not* Peter)

Title:  07/18/2016, Day Shift 23:00 – 07:00 (16:00 – 00:00) All times in UTC (PT)
State of H1: IFO locked at DC_READOUT_TRANS. 2.0W Wind is a light to moderate breeze. Microseism is low; seismic activity is slightly elevated in X, and Y but not out of line with wind conditions.   
Commissioning: Commissioners are commissioning. 
Outgoing Operator:  Ed 


End of Shift Summary:

Title: 07/18/2016, Day Shift 23:00 – 07:00 (16:00 – 00:00) All times in UTC (PT)
Support: Jenne, Sheila,        
Incoming Operator: N/A

Shift Detail Summary: Spent shift relocking in support of commissioning activities. Rode through a 5.5mag EQ in Chile with no apparent problems.   

Sheila Jenne Matt Carl Jeff

Tonight we tried a repeat of what Kiwamu and I did last week, and we were able to restore a recycling gain of ~32 (according to the POP DC/ IM4 channel, which is more like 36 according to the way we calculated it durring O1) at 40 Watts.  We moved PRM PIT 90 urad in the negative direction, and had to touch up SRM as we did that.  We moved the spot on the POPX WFS enough that we railed the PZT and the spot was off center by 0.5.  Again the spot on POP A was mostly on just the bottom 2 quadrants.   The power on the baffle PDs also decreased as we moved the alingment.  We also tried Yaw but this wasn't able to improve the recycling gain.

Since it seems like we might want to use pico motors on POPA, Jenne tried to repeat the PRM move at 2 Watts by moving PRM to match the witness sensors at 40 Watts, she could only go about half way before we lost lock. 

[Matt, Carl, Jenny, Sheila, Evan, Jeff]

The SR785 monitorring the ETMY QPD transmission has not uncovered any large hidden test mass accoustic modes in the 65-75kHz band.  It has however highlighted the fact that there is a strange 3kHz comb on these QPDs.  See this first image showing the comb (3 peaks) and the second image showing the 65-75kHz band at 50W.

This comb is present on both the fast 10-80kHz PI channels and the normal QPD A channel.  The comb appears in the X and Y arm but they are not identical.  See third image.  Also in this image the spectra before and after the whitening gain is changed (in guradian state DRMI_ON_POP) indicates that the source of these peaks lies before the whitening gain stage.

There is little indication of anything in OMC DCPDs other than these peaks being in the vicinity of violin mode harmonics - see last image.

We lost the changes to the ASC model that we made before to add POP90 to ADS.  I added it again, and did a make but not a make install.  Hopefully we can do this tomorow, if needed after the timing system work, so that we can make a dither loop for SRM.  This is svn version 13780

I restored all the HEPI safe.snap files for SDF review.  HAM1 sensor correction was the only settings needing accepting.

For the BSC ISIs, I accepted all the blend filter changes--these arose from Jim's filter bank cleanup.  The resolution for all the other diffs between the OBSERVE state and the safe.snap file are captured on the attached snapshots of the SDF diff screen before they were confirmed.

I'll do the HAM ISI in the morning.

Over-filled CP3 with the exhaust bypass valve fully open and the LLCV bypass valve 1/2 turn open.

Flow was noted after 141 seconds, closed LLCV valve, and 3 minutes later the exhaust bypass valve was closed.

AT 21:11 ITMX bias was ramped to 9.5V DAC output over ten seconds and at 21:12 ITMY bias was ramped on over ten seconds.  The interferometers was in DC_READOUT_TRANSITION with 2W.  There was no apparent disturbance.
These setting have been incorperated into the SUS_PI guardian such when it enters QPD_PI_DAMPING the bias is ramped on.  This currently happens in the ISC_LOCK guardians DC_READOUT state.  The bias is ramped to zero when entering the IFO_DOWN state.

J. Kissel, J. Driggers, B. Weaver, E. Merilh. E. Hall, H. Radkins, D. Sigg

In prep for the timing system software update, which'll need all front-ends to be turned off and restarted tomorrow, we've reconciled the SDF system in the ISC_LOCK guardian's "DOWN" state (note that in this state, some front ends are using the "safe" some are using "down" and some are using "OBSERVE" snap files). 

Notable things that we accepted:
- Bounce and Roll monitoring FMs (H1:OAF-BOUNCE_[ETMX, ETMY, ITMY, ITMX]) were found to have FM3 (a broad band-pass) in place instead of FM4 (a narrow band-pass). We reverted to have FM4 ON and FM3 OFF.
- PCAL Y 1083.7 Hz line has been off since June 28. We couldn't find an aLOG, but I recall we turned the 1 kHz line off to preserve range on the PCAL. We've accepted that it's off.
- The Beam Splitter M2 stage LOCK_P and LOCK_Y has bounce and roll mode notching filters for both the BS's bounce and roll modes at 17.7 & 25.7 Hz (FM5 "BounceRoll"), as well as for the QUADs at 9.63 and 13.4 Hz (FM7 "EvanBR"). We found that FM7 was OFF since Jun 28th, and we think we want it ON, so that MICH isn't affected by the ITM bounce and roll modes when actuated in Pitch and Yaw.
- We found the IMC Master WFS gain at 0.09 instead of 0.1, and has been so since July 13th. Seems silly, so we reverted to the gain of 0.1.
- The newish Daniel-style integrators for POP X WFS DC centering servo were found with there bleed-off engaged (via H1:ASC-POP_X_PZT_PIT/YAW_BLEEDEN), as desired since Jun 28. We accepted the bleed off ads engaged it. 
- The INP1 Yaw offset was previously -800, and is now 0.0. We accepted the 0.0, because this offset was used to PRC gain spelunking, and is now no longer in favor.

After we went through one round of clearing out, accepting, and reverting, we got mid-way through the lock acquisition sequence and lost lock back to the DOWN state again. For any further channels and changes that occurred, (especially on the suspensions), I UN-monitored those channels. 

I looked at the HEPI tidal offloading signals from one of Friday's locks to try to extract the power circulating in the arms.

As the interferometer powed up from 2 W to 40 W, the offloading signals compensated for 4.3(3) µm of radiation-induced displacement. This amounts to 130(14) kW of power circulating in each arm for 40 W of PSL power. The uncertainty comes from (1) the difference between the X and Y offloading signals, (2) nonlinear drift in the earth tides (only the linear component has been subtracted here), and (3) an assumed 10% uncertainty in the displacement calibration.

On the other hand, if we believe that there was 95(10) kW of power in each arm given 22.5 W of PSL power, we would expect 169(18) kW of power in each arm at 40 W, assuming no power-dependent arm loss. The discrepancy between the expectation and the observation amounts to 30(20)% missing power. This is consistent with previous estimates of the recycling gain loss during power-up.

This constraint could be improved by (1) making the PSL power increase faster, so that the earth tide behavior can be better constrained, and (2) turning off the HEPI offloading and instead watching the UIM offloading.

• Nothing much to report from sub-systems.
• There was some discussion of the Timing System work that will be done on Tues.
• PSL report was touched on. https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=28466
• Work Permits were gone through.