Once activities ended for Maintenance Day, immediately went for an Initial Alignment.

One item to note for alignment, was there was a lockloss where the PSL's FSS went into an oscillating state.  Toggled the FSS Autolocker.  And then Turned Off the autolocker for ISS 1st Loop (per instructions in January).

Currently have made a few attempts at locking, and have not been able to lock DRMI (other than a short 2-sec one) so far (even with nice flashing).  Have had 1-2 more instances of the FSS going into oscillation and this need operator attention.  Going to give DRMI locking a few more attempts with PRMI locks as well.  After that, may try another alignment?

Definitely not rosy after Maintenance Day and something may be amiss.  Will post update later.

We performed some noise hunting at the PSL racks today, primariliy looking at the 9MHz and 45MHz RF Amplifier outputs.  Dick assembled a passive RF rectifier which we used to measure the power fluctuations at a low enough frequency to see on the scope.  We applied that signal to a LPF and then amplified it through an SR560 with 100x gain.  An adjustable attenuator was placed before the amplifier to incrementally attenuate the signal.

After some issues with grounding, his diode was conducting too much due to a 74mV DC difference between instrument ground and rack ground, we were able to acquire some data.  Attached is a plot of attenuator value applied vs mVrms noise measured.  We gather that the noise floor is around 2mVrms.  The 45MHz signal sits right on the noise floor, no amount of applied attenuation would push this signal down any lower.  The 9MHz was different, and as we applied attenuation, the mVrms noise decreased.  It was very subtle, but worth mentioning.

D. Gustafson, M. Pirello

{Kyle, Gerardo, Chandra}

After hard closing GV20, we removed the old main volume turbo and installed the new shiny turbo at EX. We were able to leak check the GV joint with a background of 4x10^-9 Torr-L/s of helium, with no detectable leak, but ran out of time to leak check the main volume to find the air leak.

Next maintenance period we will soft close GV20 and let the {wet} turbo pump for enough time to reach a pressure comparable to main volume in order to valve it in and leak check suspect joints, and allow leak detector background to fall below 1x10^-9 Torr-L/s.

We also need to finish properly anchoring the turbo stand. Ran into a galled bolt at top plate, and a few anchor bolts are mismatched enough with pre-drilled anchor inserts that we need to file down the anchor brackets.

Good work, team.

WP 8552

Removed old fiber patch panel in MSR fiber rack to make room for new MTP style panel that will be needed for the IO chassis upgrade.

TITLE: 03/03 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Preventive Maintenance
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_CONF state: SC_OFF_NOBRSXY
    Wind: 20mph Gusts, 16mph 5min avg
    Primary useism: 0.11 μm/s
    Secondary useism: 0.33 μm/s
QUICK SUMMARY:

Active Maintenance Day Work when I walked in:

• Turbo pump work at EX, but they just opened the gate valve.
• Jenne was finishing up PRCL work.

After a few minutes, VAC team let us know they were cleaning up and ending work for the day.  Jenne finished up her work and immediately started with an alignment (X & Y arms were way off, but certainly handle-able).  Continuing with alignment!

Evan G. reported some improvement in our noise lines from Feb 11-18 (alog 55352). Alog entries (alog 55041, alog 55160) show EX Baffle Photodiode Amplifier Chassis was powered down during this time.

Today the power configuration for the unit was changed. It was previously powered by ISC ±24V rack power. It is now being powered by a bench power supply. This change isolates the unit from the ISC field rack.

F. Clara, E. Goetz, R. McCarthy

TITLE: 03/04 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Aligning
INCOMING OPERATOR: Corey
SHIFT SUMMARY: Extended maintenance day today, many successful activities. Corey has started aligning.
LOG:

• 1307 Tumbleweeder starting and passing by VPW
• 1546 Out of Observing to run PEM injection.
• 1600 Bubba, Scott, Chris to LVEA to start HAM7 and door work
• 1600 Karen to EY
• 1605 Kyle, Chandra, Gerardo at EX
• 1606 Vanessa to EX
• 1607 Jeff B to EX, EY for dust monitor checks.
• 1610 Ken to LVEA to talk with Bubba
• 1628 Richard and Fil to EX for baffle PD electronics work
• 1629 Killed the lock at 89 hours and 36 minutes
• 1631 Chris and pest crew to EY, EX, and LVEA
• 1632 Rahul starting charge measurements
• 1635 Ken out of LVEA and will be opening OSB receiving roll up door
• 1657 Hugh to LVEA, looking to move HAM8 crossbeam
• 1701 Karen done at EY
• 1710 Richard, Fil to EY, done at EX
• 1714 Jeff B done
• 1727 Chris done with Pest crew and back into LVEA
• 1729 Richard, Fil done
• 1731 Jenne to LVEA to swap SQZ PZTs
• 1737 Norco at gate heading to MY (74)
• 1747 Hugh out
• 1802 Ken back into LVEA
• 1803 Charge measurements done
• 1812 Norco at gate heading to tank 76 at CS
• 1817 Vanessa done with EX, heading into LVEA
• 1833 Tripped all SEI platforms trying to recenter T240s and STSs
• 1843 Bubba out
• 1853 Dick and Marc to LVEA ISC racks
• 1920 Jeff J to LVEA
• 1922 Hugh, Patrick to EY to look at fence
• 1945 Richard done
• 1950 Fil to ISC racks
• 1952 Hugh, Patrick back
• 2006 LSC models restarted
• 2018 Bubba, and crew out
• 2115 Jenne to SQZ racks in LVEA
• 2118 Richard to EX to check on fire panel
• 2125 HFD on site
• 2144 Richard back
• 2144 Jeff J to LVEA
• 2153 Hugh to MX
• 2157 Jeff J out
• 2211 Hugh back
• 2218 Jenne to LVEA
• 2226 Jenne out
• 2253 Richard and APS back and done
• 2314 Ed to EY to pick up a computer
• 0000 SEI_ENV taken back to CALM, enabling the SC

from EY and brought to Carlos.

• 4 energized/unused extension cords unplugged along inside of Y manifold.
• 1 energized/unused extension cord unplugged along inside of X manifold.
• 2 energized extension cords (one powering the forklift charger - forlift NOT connected to it) unplugged from wall
• North and South Cranes left with power on - bright lights a glowin'

LVEA is now good for Observing.

Today we removed the old Wireless Access Points in the Ends and Corner station and deployed the new ones that are controlled through the CDS Unify MEDM screen.  The 6 laptops that are in the computer user's room have all been updated and tested to function on the new wireless system.  Next step will be to replace the mid station units.

If you use the laptop please return it to the stand in the Computer user's room and plug it back in.

New laptops will also be deployed to the End stations to replace the current workstations.

This morning we had a hard time relocking FSS.

I bypassed auto-locker's  gain ramping (auto-locker automatically ramps the input to H1:PSL-FSS_COMMON_GAIN_CALI filter from zero to H1:PSL-FSS_COMMON_GAIN after it thinks that the FSS is locked to the right mode for more than H1:PSL-FSS_AUTOLOCK_DELAY1) by disabling the input to H1:PSL-FSS_COMMON_GAIN_CALI, set the resonant threshold low so that the auto locker wouldn't restart scanning, and observed what's going on.

It seems like there was some oscillation going on, shown in green and blue in the attached left (these are the IOP channel for FSS_MIXER_IN1). I cannot tell if this was really as low as 3kHz or if this was just aliasing.

Oscillation didn't change much as I changed various things e.g. re-enabling the gain ramping with smaller common gain, larger and smaller fast gain and  different PMC locking gain.

After 10 minutes or so while left in oscillation while I was trying things, the error signal started decreasing, the peak went higher in frequency (blue trace in DTT is 2 minutes younger than gree), and after 19 minutes suddenly the oscillation is gone (red trace in dtt).

It's locked now, but it's probably worth going to the PSL room and see signals on the oscilloscope as well as the network analyzer when this is going on.

Jonathan, TJ, Dave:

just before noon local h1lsc0 suffered a timing error, reported as ADC timeouts on all the user models. There was no disconnect between the computer and the IO Chassis, so we just needed to restart all the models to recover the system. Note: h1ioplsc0 is the timing master for the h1oaf1 computer. It appears that h1oaf1 rode through the restarts, but if we have any problems with this machine's models tonight we may need to consider restarting them.

The timing glitch is most probably related to ISC electronics work which was ongoing at the time.

[Sheila, Jenne]

Although the squeezer seems to not have gone into oscillation since last Thursday when we lowered the green power (alog 55339), we are looking to see if we can better understand the cause and ameliorate it (spoiler alert: so far we don't know, although we have further tests to try today). 

Here's what we've done so far:

• Noted that the OPO_PZT_1_VOLTS was 57.4V and had been drifting downward lately.  Recall that we don't tend to see oscillations unless the OPO locks with the PZT above 60V. 
• While on the phone with Sheila, I moved the green ISS setpoint (H1:SQZ-OPO_ISS_SETPOINT) to bring the OPO_TRANS_DC_NORMALIZED power up until we started to see oscillations. 
  • The oscillations started when the TRANS_DC was just shy of 1.7. 
  • This brought the SHG_LAUNCH_DC_POWERMON to about 17.7mW, which is under the threshold of 20mW (to prevent fiber degredation we prefer not to launch too much power in).
  • Interestingly, the OPO_REFL_DC_POWER was slowly increasing as I increased the green power, but then it jumped up a lot when the oscillations started.
  • In the first attachment (IncrPowerToStartOsc.png) you can see that the TransDC and ReflDC are increasing as I change the ISS setpoint, but around -4490sec the REFL power jumps up and we start oscillating.
• We turned off the green ISS using the Servo/Ramp button.  The oscillations were gone, but the power had gone down since we were no longer servoing to that ISS setpoint.  Turning the ISS back on brought the power back up and the oscillations back.
  • Turning off the ISS is shown at the very end of the first attachment, around -4455sec.
• I went out to the squeezer rack and changed which of the 2 PZTs that can be used to lock the OPO we were driving. 
  • We have access to both via the squeezer interface chassis in the squeezer rack's slot 12, but only one driver.
  • Sheila had brought the squeezer manager guardian to DOWN, and ensured that the PZT voltage out was near zero (~1V). Richard confirmed that it should be totally fine to switch the cables on the back of the interface chassis.
  • The driver had been plugged in to PZT1, and a terminator was on the PZT2 SHV connector. The second attachment (PZT_connectors_before_change.jpg) shows their configuration before my change.
  • I unplugged both the cable and the terminator, and put the terminator onto the PZT1 connector and the cable from the drivere onto the PZT2 connector. The third attachment (PZT_connectors_after_change.jpg) shows their configuration after my change.
• Sheila requested the squeezer manager to relock.  Using PZT2 (although the channels are still called PZT1) the OPO locked at around 26.5V.
  • The oscillations were really bad, although that was partly because the ISS was railed.  (The voltage limiter at the output of the ISS had a red box around it.)
  • We turned off the ISS and the oscillations went away. 
  • We returned the ISS setpoint to the value we'd been using that gave green power of 1.2, then reclosed the ISS and the oscillations were gone.
• We moved the ISS setpoint to re-increase the green power, and the oscillations showed up just shy of 1.6 (a little lower than when we were using the original PZT). 
  • This must have been very close to the threshold where the oscillations start, because they seemed to breathe, and then went away on their own.
    • In the fourth attachment (PZT2_oscGoAwayByThemselves.png), the oscillations start near the left side of the plot, and decay away by about -2540sec.
  • I increased the green power a small amount, and the oscillations came back. 
  • I decreased the green power and the oscillations went away, so this was definitely on the threshold of where the oscillations are happening.
    • The increase and decrease of power happened around -2500sec on the fourth attachment.
• Sheila changed the locking parameters for the squeezer guardian (the voltage at which it starts the scan for locking the OPO), and relocked the OPO at a higher PZT voltage.  It ended up being about 58.5V.
  • The oscillations were present.  I reduced the green power a small amount around -2385seconds in the fifth attachment (PZT2_higherVoltage.png).
    • The oscillations in the TransDC and ReflDC got a bit smaller, but the oscillations on the launch power completely went away.  This is new behavior.
• At this point, we are thinking about other tests, so we leave the PZT driver connected to PZT2 (we'll want to revert this at the end of our tests today).  The squeezer manager guardian is in DOWN.

I measured the optical gain for different light levels on the DCPDs before and after lowering the 9MHz modulation depth.  We did this as we relocked. 

The scan started at 2:18:40 UTC Feb 23rd, and went until 3:05:23 UTC