Today, we measured the violin modes of the new monolithic ETMy with the goal to determine what contributed to the large-ish pitch offset we were seeing.  Nothing egregious was found from violin modes themselves, so we decided to attempt to fix the pitch by re-stress-relieving the stock welded to the horns.  This technique has been done before, once here at LHO and once at LLO with success.  This time around, we went from ~5mRad differential pitch to ~500 uRad differential pitch.  Now, if only we could get a factor of 10 improvement in other aspects of LIGO in the course of a day. . . 

Jim and I went in today and tried our hand at some of the bolts on the periscope. We had high hopes since the 3IFO periscope looked good and the bolts freed easily. Unfortunately, these bolts had their hexes almost stripped on many, if not most, of the bolts (see attachments). With some breaker bars we managed to get out all of the ones we need for the vibration absorbers, and then we started on some for the baffle panel brackets with Betsy guiding us to the correct ones. Overall it was a good success with more work tomorrow. And we only bent 3 wrenches in the process!

Also, I didn't get any pictures of where we left off, check back tomorrow.

TITLE: 01/25 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
LOG:

16:03 Christina out to LVEA

16:45 Hugh out to LVEA - working atop HAM6

16:50 Set Very Large EQ button because of 5.8mag of the coast of N Cali

16:53 reset ACT SEI trip at ETMX

16:57 reset MC1 wd,  HAM2 ISI CPS trip, and ITMY ACT trip. The latter has been problematic this morning.

18:03 Jeff K out to LVEA - talk to Hugh on top of HAM6

18:04 N out to squeezer bay

18:13 Marc out to LVEA - check on ZM1; pull TTFS unit from squeezer bay.

18:22 Betsy Tj Jeff K and Jim out to EY - B&K Hammer and Reaction chain

18:27 Sheila ou to optics lab

18:29 Travis called from EY - the welding team is out there (Danny, Angus and him)

19:43 Noticed Fil out on LVEA floor at output.

21:32 Richard into CER - HV supplies

21:36 Marc out to LVEA - SUS rack by HAM5

21:50 Sheila out to optics lab

21:54 Betsy out to EY

22:04 Jim and TJ out to EY

22:45 Kissel back

22:53 Marc back

23:13 Kyle out to MY and EY

23:38 Jeff B out

23:59 Greg out to TCSY table to reset the LASER

24:00 EOS

Commissioning - 

• aligned beam into OMC QPDs;
• PZT scan is up next.
• WFS still not aligned. 
• AS Air which requires viewport simulators.
• Need to figure out feedthroughs for  the top of HAM6.
• Talk of putting internal viewport covers on septum.
• ZM2 troubleshooting is over

Squeezer -

• Ongoing
  • No weekend work is scheduled

TCS - 

• one of the tables need a new panel

Vacuum - 

• Tyler and Mark putting magnets on new ION pump
• NGG pump commissioning
  • won't happen this week

Fiber Welding -

• ETMY is welded; has pitch problems
• working on violin mode 'spreading' 
  • not quite where they need to be

Pcal - 

• B&K hammering done
• Periscope vibration absorber issues ongoing

SEI -

• Maintenance is ongoing

CDS Electronics - 

• ITMY noise investigations are ongoing

Facilities - 

• HVAC work; ongoing

Terry, Nutsinee, Daniel, Sheila

LAYOUT

Attached is the current layout of ISCT6 at LHO that is an almost identical copy of LLO. Differences at time of writing are as follows:

1) A quarter wave plate was added after the laser to reduce the elliptical polarisation out of the Mephisto and increase the transmission through the isolator to > 95% and reduce the back reflection that is awkward to dump because the rejected beam from the isolator goes vertically down and is close to the isolator mounting post.

2) Two  100 mm &  two 150mm lenses were used to mode-match the LO  and PSL LO paths (instead of four 100 mm lenses) and the seed path has two 75 mm lenses instead of two 100 mm lenses as we had run out of 100 mm lenses. This made the LO path from the PSL about 50 cm longer and the seed path a few cm shorter. The seed path was routed as originally proposed in D1500297-V5 as a lens mount was in the way and made it difficult to keep an exact copy of the LLO beam path.

3) The SHG is about 5 inches closer to the fiber coupled output end of the table than at LLO. This was just a positioning error on the table and did not compromise the setup and once the SHG was mode matched I did not feel it was worth changing.

4) The fibre couplers are about 3 inches further away from the end of the table (I accidentally left myself a little too much room to play with).

5) The fast AOM has 70% diffraction efficiency (as opposed to 80% at LLO). 

6) To get more RF power on the TTFSS detector BS5 and BS9 have been swapped from their original positiions at LLO (alog 40249)

I'll post the mode-matching solutions shortly but the coupling efficiencies into all the fibres are about 80%.

PARTS LIST

The parts in red have to be replaced with superpolished mirrors and the parts in yellow are also not superpolished but are less critical. 

Still waiting for fibres from couplers on table to patch panel and fibre switch (using temporary patch cables at the moment).

After Jenne's experience with the Kamchatka earthquake last night, I've added the requested seismic recovery button the ISI_CONFIG screen, shown on attached image. The new, green Recover EQ button is just above the old, red Very Large EQ button, and mostly just reverses the operations of the red button. If any platforms are tripped, you'll have to reset watchdogs. There's also a long standing issue of the HAM2&3 GS13 gains, which for some reason can't be stably managed by the ISI guardians, so there will be SDF differences after recovering from an bad earthquake. I've also added the low frequency Z blrms for EX&EY STS2s to the stripchart on the lower right. If all 4 channels (LSC-CPS, & 3x .03-.1hz gnd blrms) on that display are headed off the stripchart, it's a pretty good indication of a large earthquake arriving.

Ed, Jim

Excursions in BRSX include Krishna's initial visit and a code crash at the end of December

TITLE: 01/25 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 8mph Gusts, 7mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.35 μm/s
QUICK SUMMARY:

The laser tripped around 1:20 am because of the Wachhund.  I increased the diode currents by 1A for heads 2, 3, and 4.
Things seemed to have come back okay.

Daniel, Terry, Nutsinee

While playing with the TTFSS we found that very little s-pol came out of the faraday isolator before going into EOM1 (responsible for laser locking and 35.5MHz modulation for SHG locking). Sticking in a PBS cube we found 6mW of s-pol reflected and ~1W of p-pol transmitted through. We placed a half wave plate to correct for the polarization and mostly s-pol is now going through the EOM. In addition we swapped the EOM to troubleshoot a mystery 780kHz peak and phase dip in the TTFSS transfer function (it was 760kHz for the spare EOM). The peak was a result of the wrong polarization going in. Even with the correct polarization the peak was there but the phase was no longer a dip towards 180deg.

As a result, SHG locking signal needed a sign flipped and the gain needed tweaking at the beginning of the common path. 

Jenne, Sheila, Thomas

We went back into HAM6 this afternoon after the PSL came back and we convinced ourselves that we couldn't find the beam on the OMC QPDs.  

• When we got back in the chamber, we placed the fast shutter in the beam and saw that we had less clearance between the beam from HAM5 and teh shutter structure than we expected (it was less than 1 cm of clearance.)  
• We decided to move OM2 1 cm in the -X direction, to give us a little better clearance on fast shutter structure, we then rotated OM1 to center on OM2.  
• We moved OM3 about 1 cm closer to the OMC along the narrow direction of the cage (translation of the optic).  
• We removed one panel of the OMC shroud, but this was not really helpful. 
• We rotated OM3 until we saw a beam coming out of the OMC REFL path.  The refl beam was fairly well aligned to the beam dump, and we were able to see some light on the OMC A QPD. 
• We measured that the beam enters HAM6 60 mm from the -x edge of the septum window. 
• We moved the beam dump behind OM2 so that it should catch the transmitted beam, although we weren't able to see any transmission.

Fast shutter:

• We attempted to follow the fast shutter wire dressing described in 37301, but we did not have a bolt that would fit in the threaded hole on the top of the fast shutter structure.  From the drawing (here) we think we need a 10-32 bolt, between 1 quarter and 3/8th inches long.  After a long search by many people, a bolt was found, but we aren't sure it's thread is right.

Still to do:

• Find a bolt and fix fast shutter wires.
• We need to move the shutter a little bit towards the OMC to center the beam on it, and make sure that the reflection hits the copper tube.
• Move the offsets on the OMs to center the beam on the OMC QPDs and check that we do not need to offload any more alignment.
• Check that the beam is centered on all the optics in the AS_C path
• Check the AS WFS path
• Check the AS air beam using the viewpoint simulator.
• Replace OMC shroud panel. 

I'm not sure what "very large" means for earthquakes when it comes to something that seems borderline-ish, but it seems like this 6.4 in Kamchatka might qualify, so I clicked the very big Very Large Earthquake button.  It was after the S-waves had arrived, but about 400 sec before the R-waves were expected. 

The IMC unlocked, and ITMY's ISI tripped, although I'm not sure if that was before or after the transition was complete.  I leave it to Team Seismic to investigate further if they feel so inclined.

A. Bell, J. Oberling, D. Sellers, T. Sadecki, K. Toland

The final 2 fibers were welded to the new ETMy.  The monolithic was successfully suspended and IAS measurements were taken.  I'll let Jason fill in the numbers, but the differential pitch is a bit larger than we generally hope for but not grossly so.  Good work team!

Violin mode measurements to commence tomorrow.

[Gerardo, Kyle, Chandra]

This afternoon we reconfigured GV11's gate annulus ports (two 1-1/3" mini CFF half nipples). The (building) north side port is blanked off and the south side has a metal valve, all leak tight. We pumped out the gate annulus, knowing there is an outer o-ring leak; the right angle valve will remain in place during the CP4 bake.

To do this exercise we valved in small IP connected to CP1 and soft closed GV10, and then valved out IP9 and valved in main turbo pump. Y1-arm pressure alarmed temporarily. Valves are back to normal configuration (GV10 open, turbo valved out, IP9 valved back in). CP1's IP is still valved in.

Gerardo, Patrick

Ran svn update in C:/SlowControls on h0vacmr, h0vaclx, h0vacly, h0vacmx, h0vacmy, h0vacex
Ran svn update in C:/SlowControls/trunk/TwinCAT3/Vacuum/LHO/MEDM on h0vacey

Done to propagate Gerardo's update to the vacuum overview medm screen.

Turned the RF driver and the power supply on for the CO2Y laser, also connected the IR sensor, and was getting green lights for the control board. Using the PWM controller I tried to turn the laser on but wasn't getting any results on the power monitor. After double checking the power supply was set to 28V and 28A limit, and the RF driver was set to 40.68MHz, Fil and I found that the wrong RF cable was plugged in. After plugging the right one in the laser powered up in PWM mode and I was able to verify the rotation stage is working as well. Tomorrow I will check that the alignment hasn't changed significantly and that the periscope picomotors are operating correctly.