• Jason measured the beam after the 70W amplifier, for mode matching
• He and I measured power before and after the AOM, and he has the details, I recall there's about a 5W drop in power
• From after the AOM, almost no power drop to the PMC, and Jason has power measurements from after the PMC
• I took a measurement just before the bottom periscope mirror
  • A request of 2W gave 2.4W on the power meter
  • A request of 10W = 11.4W on the power meter
  • A request of 20W = 23.1W on the power meter
  • A request of 30W = 35.0W on the power meter
  • A request of 38.5W = 45.5W on the power meter, this is the rotation stage max power, at 20.02deg
  • real max power was found at the angle 20.5deg, at 45.9W
• All measurements taken with the ISS off
• All measurements take with the water cooled power meter

At 19:10TUC,  I'd restored the ISS and FSS to locking.  At 19:22UTC, unlocked, Mark and Keita are out making measurements.

The h1guardian1 machine had been up for 125 days (May9th), so we tried a reboot today during maintenance. The few issues that came up:

• Most of the ISI, HPI, and a few SUS nodes would not start up due to systemd watchdog timeouts. This is a known issue and will be addressed soon. Doing a restart one or two nodes at a time fixed it.
• SEI_HAM2 would not come up due to a lock file in the .git directory that node's archive. This lock file has to be removed by the guardian user or a sysadmin. This is also a known issue, will be resolved soon.

During cable work in the EY CER, the timing to the h1iscey IO Chassis was glitched. I recovered the system by performing a complete power cycle of h1iscey and its chassis. There was a brief negative IRIG-B excursion following the IOP restart.

TITLE: 09/11 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 6mph Gusts, 5mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.14 μm/s
QUICK SUMMARY:

• LVEA transitioned to LASER SAFE (for vacuum work and some work-permitted crane work) by Richard
• 16:20 Mark, Tyler, Chris started work on disassembling Test Stand
• H1 in DARM_TO_DC_READOUT for almost 9hrs (since 6:16utc to 14:58utc.....broke lock when I transitioned SEI_CONFIG to SC_OFF_NOBRSXY for Tues Maintenance.

Locking with higher recycling gain:

Hang Georgia and I spent some time on the steps in the guardian in CARM_5_picometers, similar to what we did a few weeks ago after an increase in recycling gain (43787).  We mainly adjusted the CARM offsets at which things happen: The step where we digitally increase the CARM gain (LSC-REFLBIAS) and engage the boost is at 65% of the ARM cavity build up, which now means a TR_CARM offset of -48, while the transition to the REFL9 happens at 85% of the arm cavity build up as before (now TR_CARM offset = -54).  This has made the build ups more stable during these last steps of the transition and we have succeeded both times we have tried since making the changes.   The TR_REFL 9 input matrix element is now 2, where it used to be 3.

In DRMI on POP, Hang adjusted teh DRMI gains by changing the input matrix.  The MICH ugf is around 9 Hz (as it has been) SRCL is around 40 Hz (it was 60 Hz earlier today), and PRCL is around 50 Hz (was around 30 Hz earlier today).   

In the last few locking attempts we have locked with the ASC error signals close enough to zero that we could engage the ASC loops without any problems, although I know that was not true earlier in the day.  I'm not sure if people reset alignment references.  

HARD Y loops:

In alog 27832 Jenne shows some measurement of HARD yaw loops that do not have the non minimum phase feature that has been bothering us.  

Hang and I re-ran Gabriele's template for measuing CHARD Y, and see that the spot centering efforts haven't changed that feature much.  We also saw that DHARD Y is fairly cross coupled to the CHARD, you can see that our CHARD excitation shows up in the DHARD error signal about a factor of 3 smaller than in the CHARD error signal. 

I sent a line at 8.1 Hz to both ITMs, and adjusted the output matrix to minimize the signal in DHARD Y, I found that I needed a gain of 1.07 in ITMX (with 1 for ITMY) to balance them.  I tried the same for the ETMs, but they were closer to balanced.  I changed the output matrix element for CHARD and DHARD Y to ITMX to see if this would have any impact on the transfer function or the cross coupling to DHARD, but it didn't have much of an impact. 

Leaving IFO locked

I am leaving the IFO locked at DC readout with 2 W input power, a2L is running.  I used the guardian to engage violin mode damping, it is damping 7 modes on each test mass, and they all seem to be fine. 

Prep. for leak testing tomorrow

[Sheila, Nutsinee, Terry, Haocun]

We looked into more of the cavity scan of the OPO, especially on the polarization issue.

Several main conclusions are:

1. We looked into SHG_FIBER_REJECTED and the ratio between OPO_REFL_REJECTED and OPO_REFL under different green power input.

The wrong polarization increased linearly with the ratio remains the same, which means the polarizer on the VOPO platform does work well. (Fig attached 1)

We have a ~7% of power wrong polarization coming out from OPO as measured on SQZT6.    

2. I tried to minimize the wrong polarization ratio by tweaking the waveplates before the input coupler on ISCT6, but unfortunately this helped little by only getting a changing of ~0.1%.

3. We have a polarization mode very close to our 00 mode (~MHz spacing, I will do more precise calculation) (Attachment 2, zoom-in plot 3). This can been seen by comparing the opo trans lining up with rejected.

Not sure yet whether and how this will effect the error signal, etc. 

Next steps:

- Modeling of the error signal asymmetry based on PDH and scan asymmetry with thermal expansion.

- Install PBS in OPO Trans path to have a clearer idea on the polarization mode.

- Maybe: tweaking the crystal postilion to see whether we can separate the polarization mode further?

I looked around at signals on the PSL and in the IO path, and found two things.  The first, which is probably unremarkable, is that when the RefCav Trans PD went to 0, the ISS QPD, and IO GigiE cameras don't see a change in the beam alignment.  The second is that when the PMC heater power changed, going from 30 to 60, that change steered the beams coming out of the PMC, as seen on the ISS QPD, and IO GigiE cameras.

Many plots, but the first and last give the most pertinent information. 

• the first plot shows the PMC heater power change, and how that's seen on the GigE cameras
• the last plot shows the FSS Trans going to 0, and the beam alignment sensors as unchanged (to the level that we expect, when the PMC unlocks and relocks)
• the 4th plot (from the right) shows IMC relocking during the heater power change, and the PZT response
• the 8th plot (from the right) shows the ISS QPD DX nd DY and the PMC heater power

TITLE: 09/10 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 5mph Gusts, 3mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.19 μm/s 
QUICK SUMMARY:

Commissioners busy working on H1.  The PSL issues weren't observed in the morning, but appeared to go away after a FSS VCO power cycle by Keita.

• Commissioning began with alignmment by Gabriele since the PSL appeared to be fine (compared to having issues 
• 16:38 Fire Dept recovering vehicle at EY, will need to move over 
• 16:45-17:15 Ed covering
• 16:46-17:33 TCS Chiller visit (Thomas, Dan, TJ)
• 16:47 Checking LVEA test stand/plug forklift (Mark & Tyler)
• 17:27 Vanessa out to End Stations
• 18:49 SQZT6 visit by Sheila/Terry....will want to chat with Haocun
• 18:50 PSL/FSS issues from weekend returning.
• 19:00 FSS VCO power cycle to address above issue (Keita)
• after 20:00 EY copper tubing work in Fan Room (Mark & Tyler)
• 20:05 Ken at warehouse
• 20:43-22:00 ISCT6 work (Nutsinee)
• 22:20-22:40 EX computer check (receiving, not VEA) by David B.
• 22:01 Dessicant packs  put into SUS pelican case in LVEA (TJ)
  • While leaving LVEA, TJ noticed LOUD Beeping.  This is a known issue regarding a UPS for the PSL.  See previous note about this LOUD beeping back in July.
  • Will tag this alog with DetChar in case someone wants to look at these beeps with microphones (in case this issue slips through to O3).
• 22:45 Gerardo out to End Stations to pick up some cables which will be needed for tomorrow.

Announcement:  Fire late Fri night w/ water pump alarms following.

- If any one sees a fire, let Jeff Jones know, so they can address regarding operations.  One can call 911, or non-emergency number, which is listed in our phone roster.

Commissioning: 

• Sat:   investigate ITM/ETM alignments, then PSL issues.
• Check White Board for this week's activities

Tues Maint

• Time:  Not clear....4hrs or more?
• Transition to Laser SAFE first thing in morning (get work permit filed early)
• Gate Valves Closed
• Charge (normal one)
• SEI CPS (power cycling chassis, re-seating board in chasis, etc.)
• BSC T240's recentering 
• PEM accel ham6 cable run out
• EY ESD power supply cable pulling
• Kepco power supplies (time permitting)
• VAC:  LVEA leak check which requires gate valve closing, need spinning corner turbos on Mon afternoon (commissioning says should be OK), 
  • regenerate neg#1 & heat up for an hour
• Guardian reboots (TJ)

Other Items:

• Safety Review occurring later this week on site.
• All Hands Meeting on Friday in MPR.
• Safety:  Be safe outside even when not at work (be careful with household machines/tooling, as a pedestrian, etc.)

The MY weather station stopped reporting at 23:16 PDT Friday 7th September. This matches the time this area was hit with lightening. I restarted the code and the weather station is reporting again.

Quick update.

First thing this morning, when preparing to address the FSS not locking issue, we found that the IMC was locked and the PSL status appears to be nominal, at least the FSS.  The ISS was not locked but acquired quickly when the loop was enabled.

GabrieleV is investigating and pressing ahead with trying to lock the ifo.

At around Sep 09 2018 07:10:53 UTC (GPS 1220512271), the IMC and FSS lost lock.  I was unable to recover the FSS.

The FSS is railed at about 11.9 volts.  I can move this value around by turning off the autolocker and moving around the common and fast gain sliders, but as soon as I reengage the autolocker it rails again.
The laser crystal temp at the time of the unlocking was 0.31 K.  I tried manually setting the temperature there, but the PZT just is not responding, and every time I ask it for control it rails to 11 V.

I pressed pretty much every button and shook every slider on the PSL_FSS medm screens.  I don't know what else to do from the control room.  My uninformed opinion is that somehow the PZT lost it's lower DC power rail, since it always rails positively.
However, I can get the Fast monitor to read negatively if I disengage the autolocker, turn on the "mode loop" (no idea what that is), and turn up the fast gain (Picture 2 below), so I'm not sure what's actually going on.

[Hang, Craig, Gabriele]

Summary

We moved PR3, PRM and the soft degrees of freedom to improve the beam centering on all four test masses and increase the recycling gain.

We started with a recycling gain of about 38.2 and finished with a recycling gain of 47.4 [+24%]

A lock loss terminated our work, so there is still some re-alignment to do to get the test masses centered. And there might be more recycling gain.

We added dithering lines in yaw to all four test masses, and we could improve the centering significantly. At the end all Y2L coefficients are zero, and the dithering signals are quite close to zero. The two ITMs are reasonably centered, as is ETMX. Instead ETMY seems to have a larger mis-centering.

If we need to put back the Y2L coefficients, we probably only need to set ETMY to about 4.

Details

• We moved PR3 as we did in the past days.
• We had to compensate the PR2 alignment offset since the offload was clipped at the limiter
• From time to time we also adjusted the soft degrees of freedom position, by opening the loops, optimizing the power, and adjusting the QPD offsets
• We did the same with the POP QPD. Finally we were hitting a large offset, so we pico'ed the QPD
• We also moved the ALS POP QPD to keep the green beams in ggo shape on the cameras
• We also updated the green references, by moving the green QPD offsets and adjusting the camera set points [not quite to the last position, since we lost lock, but it should be quite close to good...]

We finally lost lock after more than 6h continuous lock.

(In this post I mean "railing" as "parked at the maximum actuation range", where "oscillation" means "PZT is fighting the EOM")

The FSS Fast Path has been railing recently, preventing the FSS from locking.  (Pic 1)

It seems as though FSS_OSCILLATION does not in fact monitor the FSS RMS, but triggers on a threshold.  When the FSS voltage would pass a certain value, the PSL_FSS guardian would send it to state FSS_OSCILLATING.
This state brings the common gain down to -10 dB, then slowly back up to wherever it started.  This works great for stopping oscillations, but not for permanent rails.

I modified the PSL_FSS code to increase the oscillation threshold from 0.6 to 3 V for five seconds whenever the fast voltage is railed at greater than 10 volts with extremely low RMS.  This should allow the FSS loop to close and bring the temperature within range.  Railing hasn't happened again, so I haven't had a chance to test the state, but it does still suppress actual oscillations.

We've had two measurements which suggest ITMY actuation is weaker than it should be, (Georgia's measurement of the ITM ESD actuation strengths 42315 and 42302 and Gabriele's measurement of the ASC actuators 43797), so I have double checked the optical lever calibration. 

I found a time in the past when (August 13th at 21:22 to 21:25 UTC) we ran the script that adjusts the alignment of the ITM by pointing the green beam onto the EMT baffle PD's. 

The optical lever indicates a 16.5 urad change in ITM pitch between the time when the beam hits PD1 and PD4, and a 14.1 urad change in yaw.  

According to the drawing that Keita and Gerardo put together, 9087, the ITM pitch difference between pointing to the two diodes should be 11.76''/4km/2 = 37.2 urad pitch and 37.4 urad for yaw.  

This means that our current calibrations (pit gain = 23.9 yaw gain = 24.0) are too small by 2.25 for pit and 2.65 for yaw. 

I have not attempted to check the slider calibration since people are locking the interferometer right now. 

The calibration has not changed since October 5th 2014, and this is the closest alog I can find: 14312