TJ, Nutsinee

Per Aidan's request we misaligned ITMs and moved ETMs around to see if the CR HWS sees any reflection from the ETM surface. HWSY streamed images didn't appear to have any residuals from the ETMY but HWSX saw some light from the ETMX.

Here's HWSX with only ITMX misaligned (ITMX delta YAW = -191.3u)

And here's HWSX with both ITMX and ETMX misaligned (ETMX delta YAW = -110.5u)

We also appeared to have this mesh-looking feature on the left hand side. Stray light?

LN2 consumption is derived from the liquid level of the storage dewar. Nominal rates across the site are usually around 1%/day. CP3 failed Dec21/22 2015.

Plots for Nov 2015, and April 2016 show rates of 1.07%/day and 1.25%/day. The plot for Feb 2016 shows a noisy signal. For May 2017 we get 1.25%/day

The increase in consumption in the period may be due to the manual filling operation or a loss of vacuum in the CP3 dewar insulating jacket.

A liquid nitrogen delivery in December made the dewar level signal noisy for a while.

This morning I noticed that the PMC was reflecting close to 20 W, which is unusually high; the PMC was transmitting 56.4 W.  Some of this increase is due to the continued decay of HPO Diode Box 1 (decay changes the thermal lens in Head 1, which changes the mode of the output beam of the HPO, which then changes the mode matching into the PMC).  Until the spare DB arrives from LLO this is what we have to work with, so I tweaked the beam alignment into the PMC to gain as much transmitted power as possible.  The PMC is now transmitting 59.1 W and reflecting 15.3 W.  This closes LHO WP 6661.

FAMIS 3652: PSL Power Watchdog Reset

I reset the PSL power watchdogs at 16:02 UTC (9:02 PDT).  This completes FAMIS 3652.

FAMIS 8424: HPO Pump Diode Current Adjustment

No adjustment performed this week as the PSL output power has not changed since last week.  This completes FAMIS 8424.

TITLE: 05/30 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Maintenance
OUTGOING OPERATOR: N/A
CURRENT ENVIRONMENT:
QUICK SUMMARY: ops lazy script isn't doing transition (-t).

After Sheila left today, I tried locking the interferometer several times with no success. The below are some notes.

• As reported in 36447, completing the ALS sequence was very difficult today.
  • Locklosses were not associated with the power drop of the X green laser.
  • ALS DIFF seems to unlock often when it is in action (e.g. FIND_IR). Otherwise it seems stable and was stable enough to pass through DRMI.
  • Lowering the ALS diff gain by a factor of two (400 -> 200 in DARM1) improved the situation (not in the guardian). This smells like some glitches somewhere in ALS.
  • I was able to pass the ALS states consistently after lowering the gain.
• LOWNOISE_ASC was not stable.
  • I didn't have time to investigate, but some instabilities occurred in a yaw degree of freedom. Perhaps it is the same as 36476.

The ice blockage has opened up on CP3! See last VE log entry. Kyle and I connected full T-sized GN2 bottle with acrylic rotameter (5 LPM range) to the sensing line and started out flowing 1 LPM. The flow held and we noticed fluctuations in the exhaust pressure (0.2-0.4 psi). Then I got antsy and bumped flow up to 1.5 LMP and it slowly increased to 2 LPM. The signal value (% full) is slowly growing! We saw exhaust pressures as high as 0.8 psi and signal value up to 10%. We are leaving it flow at 2 LPM overnight with shift-monitoring and -logging. Kyle will log odd hours and I will log even hours. We are being overly cautious about the not boiling CP3 dry overnight.

I noticed on-scale values for CP3's level for a few snapshots - could it be?