Due to some extenuating circumstances, Travis, Richard, and I moved the remaining hardware out of the 2 large 16' assembly cleanrooms in the west bay of the LVEA and turned them off.  There is still a small cleanroom on against the West wall of the LVEA which we will turn off in a few weeks when we are finally finished kitting 3IFO hardware.

12 hour OpLev trends starting 5:51:04 UTC.  No obvious issues.

All scans look normal except the frequency scan (dbb_frq-001.pdf); scan shows some interesting features between 1 and ~20 Hz.  As of our PSL maintenance yesterday we know there are some issues with the FSS system (see alog).  We will continue to investigate this as time, and commissioning, allows.

Just getting ranges correct and consistent for display of reds & greens.  All pressure lights are now Green and OK.  The SERVO database is set up so restart does not affect the HEPI platforms too much.  I of course would not do this if anyone was running any tests.  The times are: EY 1603, EX 1619, CS 1638utc.  Attached is 40 minutes of second trends with these times annotated.  The corner station pressure glitch was non existent, the ends had glitches of a few PSI.

When I look at the HEPI L4Cs during this pressure glitch, it looks like it is absorbed into the normal background glitching.  See the latter two attachments.

SEI: nothing to report
SUS: nothing to report
Aidan and Alastair: Ready to put TCS 3IFO parts in LVEA
CDS: PEM work, cabling microphones, H2 room work
Facilities: beam tube cleaning

Safety meeting at 3:00 in LSB

I've turned all 4 RHs on to 2W total each (1W per segment) for 30 minutes this morning to get some data for Installation Acceptance. They will turn off again around 8:10AM.

The thermal lens should deteriorate to negligible by around 9AM, if not before.

Grills and dampers are installed in the DCS duct work. Remaining tasks include start up of the AC units, installation of the smoke detectors and some electrical.

Sheila, Dan, Daniel, Evan Jeff, Lisa, Alexa

Starting at 08:43:06 UTC Feb 11, 2015 we had a DC lock for ~1:54min. We lost lock again because of the 9 Hz bounce mode in ETMY. We had tried damping with the L2 stage, which helped a bit but still ultimately caused the lock loss.  Tomorrow we should try damping with M0, as done at LLO (LLO#16686).

We have seen in our two DC readout locks tonight what looks like it could be a fringe wrapping shelf in DARM. 

We transitioned to DC readout at 8:43:06 UTC Feb 11 and it is still locked.  If anyone could make a spectrogram of LSC-DARM_ERR durring this time, that would be interesting.  We made an attempt to do this using ldvweb, but didn't suceed yet.  

Alexa Daniel Dan Evan Jeff Lisa Sheila (+ many others)

Like a coffee hipster who won't touch beans that haven't passed through a civet, the IFO now measures DARM_ERR with the light transmitted through the OMC.

After the BS WFS were commissioned earlier today, we had several steady locks with 2.8W input power in which we attempted the handoff to DC.  We measured the DARM loop gain and set the UGF to be at the maximum of the phase bubble to make the transition as stable as possible (30Hz, ~30deg margin).  We experimented with different DARM offsets and settled on 5e-5 counts; with a preliminary calibration of 3x10^-7 m/ct this corresponds to an offset of 15pm.  The carrier TEM00 mode was somewhat larger than expected (see the attached pdf, peak at ~43 volts), about 15mA in DCPD sum, almost as much as the 45MHz sidebands.  We used this DARM offset for the rest of the evening.

We measured the OMC-DCPD_SUM --> DARM_IN1 transfer function and adjusted the OMC-READOUT_SCALE factor and LSC-OMC_DC_OFFSET to enable the handoff from AS45_Q.  The values we used are an offset of -2.33e-05 counts and a gain of -2e-6, these values were tuned at the few percent level in subsequent locking attempts to match gains as well as possible.  (Note that the gain comes before the offset, which makes trimming a little more straightforward.)  After these were applied the OMC-to-DARM noise TF looked like Fig. 1.  At this point we attempted the handoff to DC.

This blew the lock.  We realized the OMC input to DARM was subject to the normalization factor of sqrt(NPTRX).  We implemented an awkward fix by holding the output of the TR_X and correcting for the power normalization in the OMC-->DARM input matrix element.  The correction factor is 6.25, this changed by ~1% from lock to lock.

After that, the handoff to low noise worked.  The OMC DCPDs currently have no whitening enabled because the ETMY violin modes (at 508.1 and 508.2 Hz) are rung up and even a single stage of whitening will saturate the ADC.  So, we are ADC noise limited above ~400Hz.  One of our next steps will have to be the commissioning of the violin mode damping.  The ETMY bounce mode is also rung up; so far this isn't a problem, and we are nervous about turning on the damping before we're ready to end the lock.  A spectrum of the DCPD noise is in Fig. 2.

Rick S., Jason O., Matt H., Ed M., and Jeff B.

Went into the PSL today and performed a few maintenance tasks (work permit #5039).

1) Measured PSL power at several points in the beam path:

• 33w - between M1 & M2 (just outside of the front end)
• 26w - reflected from PMC
• 27.2w - incident light on PMC
• 24.4w - downstream of the EOM (in the IO section of the PSL table)
• 24.9w - PMC transmitted

• 67.5mW – upstream of the FSS AOM
• 54.5 mW - Single pass power, upstream of M25 (81%)
• 36.3mW - Double pass power, upstream of FSS EOM (66%, 54%)
• 33.7mW – At top of periscope mirror, incident on RefCav

3) Measured voltage of RefCav REFL PD (H1:PSL-FSS_RFPD_DC_OUTPUT):

• 299mV – With FSS RefCav unlocked
• 165mW – With FSS RefCav locked
  • This is too high, giving a RefCav visibility of only 45%!

Once again the RefCav Trans PD (TPD) has begun to drift down.  Was set to ~1.6V on 1/5/2015 (see alog 15871) and today is reading ~0.9V.  Therefore we adjusted the RefCav alignment by adjusting the vertical and horizontal of the top periscope mirror.  Measured voltages at the RefCav REFL PD.

• Vertical adjustment dropped RefCav to 83mV
• Horizontal adjustment dropped RefCav to 65mV

After adjustment (and locking of adjustment screws):

• RefCav REFL PD - 300mV (with FSS RefCav unlocked)
• RefCav REFL PD - 60mV (with FSS RefCav locked)
  • This gives a FSS RefCav visibility of 80%, which is better.  Per Rick S. this should closer to 98%, so some more work to do here, but is good enough for now and we were running out time in our maintenance window.
• RefCav TPD - 1.63V (H1:PSL-FSS_TPD_DC_OUTPUT)
• RefCav transmitted power - 19.1mW

Will keep an eye on this as the RefCav transmitted power seems to drift down suddenly.  We’re not sure what’s causing this apparent alignment drift.  All the measured powers leading up to the RefCav were close to those measured during the 1/5/2015 adjustment, but the RefCav TPD was still reading ~44% less.

4) We also measured the UGF of the FSS:

• UGF: 200kHz, phase margin 35 deg
  • According to Rick S. this should be closer to 600kHz, so we have some work to do here.
• At 500kHz: -6dB, phase margin 58 deg 

5) For Daniel, we adjusted power at IO PD (IO-AB-PD3-DC) to 3.3V by turning up the PD gain by 3 clicks and adding a ND filter to the PD (see Daniel's earlier alog).

6) We are now storing the 2 3IFO PMCs in the NW corner of the PSL LAE on a cart, with their lids off.