Sheila, Ronaldas

Sheila suggested to investigate bullseye sensor noise contribution to DARM. It is basically a coherence based projection of jitter from the bullseye sensor upstream of the PMC, which was contributing to the DARM noise from 30Hz-1 kHz in this lock stretch (4th of July).

Bullseye sensor readings seem to be coherent with DARM signal on YAW and PIT d.o.f., see 'bullseye_yaw_pit_coherence.jpg'.

This sensor measures jitter that we believe is driven by the turbulent flow of water over the crystals in the high power oscillator. The acoustic or PZT injections in the PSL which can reproduce the jitter peaks seen by sensors downstream of the PMC cannot explain the level of noise coupling that the coherence suggests for jitter sensors before the PMC. We are relying on the observed coherence between this sensor and DARM to estimate the noise contribution.  

Nonetheless we tried the following:
1) choose maximum coherence d.o.f. for bullseye sensor (either YAW or PIT)
2) if coherence with DARM is bigger than 0.01 for a frequency bin, include it as a noise
3) then the bullseye noise is simply sqrt(coherence) * DARM

Result can be seen in 'bullseye_sensor_coherence_noise.jpg'. This noise contributes quite a lot for f>100Hz and improves noise budget, see 'compact_nb.jpg' and 'full_nb.jpg' [cyan dots in the plot]. For a comparison, previous noise budget plot can be found here (previous noise budget).

While the result seems encouraging, we need to investigate it for other locks. This coherence projection was done for 4th of July, 2017 (GPS time: 1183190418, duration: 600s), before the earthquake. Note that we expect this noise source to be reduced for commissioning/O3 because the high power oscillator has been replaced with the 70W amplifier.  

Summary

TMSX needs to be YAWed by about -250 urad (YAW slider from -329 urad of Feb/06 X arm peek to -585 urad today) to make the ALS X beam retro reflect by ETMX.

Old ERMX wedge seems to have been about ~590 urad, thus deflection should have been (1.46-1)*590=270 urad horizontally, but now the wedge is entirely gone.

We know that ETMX angle is pretty good as of now within ~+-80urad or so from PCal reflected beam. We know that TMSX suspension didn't change angle by O(100urad) since February.

Unfortunately, with the new offset TMSX suspension DAC is already railing, so we need a physical rotation to relieve it.

Old ERM wedge

Old ERM spec is pretty loose, 0.04+0.04-0.03 deg = 700+700-500 urad (in horizontal direction, it seems).

In the case of old ERMX, which is ERM-02, the Vendor report (C1001321) shows that the edge at 180deg position is 0.2mm thicker than the reference edge at 0deg, so I'd guess the wedge is 0.2mm/340mm =590 urad. The same report says something about parallelism of 0.02mm but I don't know what it means. There is also GariLynn's transmission data E1200019 but I don't know if Zernike Tilt coefficients on the report represent the wedge or not.

IF the wedge was indeed ~590urad, using n~1.46 at 532nm, the deflection should have been 271urad before ERM replacement.

(For ERMY 0.25mm/340mm~735urad, deflection ~340urad, on the same order as ERMX, Vendor report C1001320).

What was done

After Betsy and Travis are done with ETMX oplev and confirmed that PCAL beam reflection is right on the detector within +-1mm or so (which means that the ETMX angle is good within of  ~+-1mm/6m/2=+-80mrad), I fired up the ALSX laser, turned on the QPD centering, went in to the chamber, removed the ERM cover, came out and changed the TMSX alignment offset to obtain retro-reflection. I had to basically rail F2 and F3 coil that are used for YAW.

There apparently was a big YAW shift, but I don't see any M0 stage jump nor drift since February. I and Corey moved LF, RT and F1 BOSEMs at some point, but the actuation of a BOSEM should have much smaller dependence on the magnet depth than the sensing, and anyway these shouldn't and didn't affect YAW. See attached.

After this ERM cover was put back on, ALSY was turned off, and EY station was put back in laser safe.

Betsy reported that they ran a quick transfer function and saw no touching/rubbing.

What about Y?

TMSY Yaw offset used to be pretty small (between 0 and +10urad last year when ALSY was regularly locked), but after ERMY swap we had to set the YAW offset to -217 urad (40793). As was noted above, IF the wedge could be read off of the thickness measurement by the vendor the deflection should have been 340 urad. Not as satisfying an agreement as X, but still on the same order.

Ken D., Tyler G. and Mark D.

The power cords connecting the 480 VAC manual variac, duct heaters and recirculating fan from their respective control panels were disconnected.  Now the variac and heater control panel can be moved out of the way.  Also, all of the added foam insulation board, aluminum foil and "rock wool" insulation has been removed from the VEA. 

Scan taken this morning (see attached).   This is "unofficial" but is promising. 

(Kyle R, Gerardo M)

Today after lunch we removed all aux cart equipment used to pump down BSC1 and BSC3 annulus systems, then we moved to do a gross leak check of disturbed joint conflats, background for the entire procedure remained under 10-09 torr*L/sec.
Helium leak tested the viewports/blanks installed on HAM2 and HAM5, and the new installed ion pump gate valves (IP1 and IP2).  Kyle noted a couple of viewports that had tape indicating that needed testing on BSC2, leak checked those as well, and removed the tape.  No gross leaks found.

TITLE: 05/10 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

Started covering for Cheryl at 10amPDT.
LOG:

• Moving snorkel lift out of High Bay to MY (Mark & Tyler) 
• 17:00 Finished EX HEPI Fluid work (Hugh)
• 17:00 EX Laser HAZARD for alignment of ETMy via PCal laser (Travis)
  • 17:00-18:13 Beginning work for ETMy. Transitioned to SAFE at lunch. (Travis & Betsy)
• 17:00 Emer-Stop button (Fil)
• 17:11 Installing cable tray hardware (Ken)
• 17:40 Turned ON RF Modulators at the PSL Rack, and now the RFAM FOM looks better! (Daniel)
• 17:42 Work at the vault (Marc, Fil)
• TJ covering for me from 18:05-18:55
• 1814 Sheila transitioning LVEA to LazHaz
• 1827 Keita to EX to check the alignment with ALS. will be LazHaz
• 1833-19:00 Sheila and Jenne to IOT2L
• 1850 Georgia turning on HV at EY to start charge measurements
• 1853 Greg to LVEA to get numbers for TCS AOM
• 20:13 MY CP4 Oven disassembly work (Mark, Tyler, Chris, Ken)
• 21:21 Beam characterization work in Squeezer Enclosure, LVEA Laser HAZARD already, but they'll energize the signs in Squeezer Bay for this work (Thomas V, Dan B.)
• 21:30 Decouple Annulus ion pump plumbing from BSC1/3 (Gerardo)
• 22:12 Began receiving high pressure Verbal Alarm at BSC2. 
• 22:40-22:59 IMC phasing work (Sheila, Craig)

ETMX OSEM Open Light Values (OLV) remeasured, offsets and gains adjusted:

Main Chain Top

Reaction Chain Top

L1 (UIM)

L2 (PUM) TBC...

All values updated in the SDF SAFE file

[Sheila, Jenne]

When Sheila first opened the light pipe, we weren't seeing beam on IMC REFL camera.  We went to the table with a card and moved the PZT until we were back on the camera.  I had previously set the IMC optics back to the bottom stage OSEM positions from the last IMC lock.  This got us flashes.  The IMC is now locked, although the alignment is very poor - we'll continue to work on that after the meeting, but should be ready to send beam to HAM 6 this afternoon.

• 10-05-18 14:14 JeffB to EX to reset dust monitor 2
• 10-05-18 15:10 JeffB back
• 10-05-18 15:22 APS truck1 on site
• 10-05-18 15:58 APS truck2
• 10-05-18 16:12 Karen done at EY heading to MY
• 10-05-18 16:23 Hugh to EX to check on HEPI
• 10-05-18 16:25 Mark and Chris to LVEA to move the Snorkel lift out and to MY
• 10-05-18 16:30 Fil to LVEA to work on E-stop button - not yet connected to the PSL - SQZ is down so safe

Work, by group:

• VAC: potential to open PSL shutter to be evaluated today
• Transition the LVEA to Laser Hazard
• IO: lock the IMC
• HAM6/SQZ: check beam alignment
• Locking: other plans as time/personel permit
• TCS: potential work on the tables

Work, by building:

• EY: no work planned
• MY: start the disassembly, as time permits
• CS: if possible, Laser Hazard, 1064 and TCS alignment work
• MX: no work planned
• EX: ETMX work continues

   Have shutdown dust monitors LVEA #5 and End-Y VEA #2 and removed them from the check_dust_monitors_are_working script. Dust monitors remaining in the check_dust_monitors_are_working script are in use and should be monitored by Ops per the checklist.  

We iterated between IO_MB_1 and IO_MB_2 without moving EOM as planned. One difference from the plan was that it was my misunderstanding that Cheryl had two irises on the main beam path (there was only one), so we used EOM and iris as our fiducial.

As expected this made ALS path totally misaligned such that it doesn't clear Faraday, that will be adjusted later.

I wanted a quick first guess of new gains to use for the RF locking signals, so that we know roughly where to start when trying to lock DRMI, since the drive levels are slightly different with the new EOM.  I'm using Koji's measured values from alog 41435.  Note that the drive levels are slightly different now, since the EOM drivers have been moved to outside the PSL enclosure (alog 41852), but they're pretty similar.  Our final gains will of course be set by measuring the loops, so this small discrepancy in the first round guess shouldn't really matter.

The amplitude of a PDH signal is proportional to J_0(Gamma)*J_1(Gamma), where J_n() is the Bessel function, and Gamma is the modulation depth in radians (see, for example, P1500001 appendix B for a derivation).  The ratio that we will want to apply to the old gains will be:

ratio = ( J_0(Gamma_old) * J_1(Gamma_old) ) / ( J_0(Gamma_new) * J_1(Gamma_new) ). 

For the 45 MHz channels (Gamma_old = 0.287, Gamma_new = 0.197), the ratio will be 1.43. For the 9 MHz channels (Gamma_old = 0.187, Gamma_new = 0.210) the ratio will be 0.89. 

Betsy, Sebastien, Slawek


Work on installation of AMDs on ITMx and ITMy has been completed. 
Each test mass has now 4 AMDs glued to the suspension flats.  All AMDs on ITMy are glued slightly lower than the nominal AMD height position. It appears that quad suspension of ITMy is  ~5 mm longer than the ITMx quad. We have noticed it after AMD installation. This new AMD position should not cause any AMD performance degradation neither increase thermal noise according to our simulation.
Additionally, due to the scratches on the test masses flats we decided to move AMD 4 on ITMx and AMD 4 on ITMy. The exact gluing locations are shown in the attached drawing.
The curing dynamic test of the epoxy EPOTEK 302-3M of all batches was passed, see attached picture.  The bond between AMD and TM looks good for each AMD (see the back face image of the AMDs). 
We can call this installation 100% successful.