Since we postponed the HAM1 in-vac mission today, we moved on to the interferometer alignment for now.

Here are what I did:

• The forward propagating beam was steered on the in-vac POP A and B QPDs.
  • To make the signals bigger, I increased the whitening gains of the QPDs from 0 to 45 dB.
  • Although the readouts are very tiny i.e. POP_A(B)_SUM ~ 4 counts, this was big enough to be discriminated from back ground noise.
  • This was done by steering IM4. I had to move IM4 mostly in pitch.
• PRM was then realigned to this new IM4 alignment such that we keep having the retroreflection back to PSL.
  • This means there is no impacts on the interferometer REFL paths.
• The PR2 and PR3 alignment were restored back to July 25th 1:00 AM PDT by using the bottom mass OSEMs as a reference.
• The BS alignment was restored back to July 25th 1:00 AM PDT by using the oplve as a reference.
• ITMY DC bias was restored back to July 25th 1:00 AM PDT.
  • We didn't trust the oplev for ITMY.

The attached is a screenshot of the resultant vertex alignment.

Travis, Angus and Alastair contued with the weld practice at end Y. Travis welded in all 4 practice fibres on the test set up and hung the dummy mass. We re-arranged the weld trolley and fibre preparation table positions to allow line of sight for Doug's alignment tooling during the welding. All tooling is functioning as expected. Tomorrow first thing we will remove the "old" ETM from the structure to allow TCS to work on the ring heater and then pop in the "new" ETM in the afternoon and do full alignment of the masses in preparation for welding again on Thursday

Days Activities

• Welding work continues at EY (practice welds and being filmed as well)
• EX was transitioned to Laser Hazard for ALS work (Alexa/Sheila)
• Kyle has begun pumping down at EX
• H1 SUS HTTS was rebooted (Dave/Arnaud)
• ITMx Oplev & electronics work (Thomas/Filiberto)
• Cleanroom was moved from BSC2 -> HAM4 (this required GV2 to be closed/opened)
• HAM4 HEPI electronics work (Hugh)
• Had another SUS Watchdog INVALID alarm for everybody.  Also get ALH Warning window saying there is a virtual circuit unresponsive context:  cdsegw0.cds.ligo-wa.caltech.edu:33029
• CP2 was filled (receiving overfill alarms)
• Sheila gave another PSL Operator Training session in the Control Room

[Jeff Dave Arnaud]

After Keita reported he couldn't access to tip tilts medm screen to damp the suspension (which hasn't been updated yet), I looked at RM1_M1_OSEMINF signals to see if I could damp it from the command line. Although, the readback was zero even though we were seeing numbers out of the ADC, which directed us to a model issue. Some modifications from last week would prevent the model to compile properly so we undid some of the changes and fixed some other issues. After restarting the models after the changes, the channels were back alive. Last thing to do is to resurrect the medm.

Modifications made on

**h1sushtts.mdl** (1st screenshot)

1) Grounded the calibrated ISI signals outputs from HTTS

2) Linked the ISI signals directly from the IPC to OM1/2/3, instead of the ones going out of HTTS

3) Changed ADC7 to ADC0

4) Modified the channels to match with 3)

**HSSS_MASTER.mdl** (2nd screenshot)

1) M1/ISIINF CdsEpicsOuput banks changed to CdsFilt banks

As soon as we flipped the beam diverter open we got the REFL beam on ISCT1.

Then we went into HAM1 and noticed that the beam was moving by a huge amount in PIT. TTs were not damping at all. Turns out that that was a TT model problem. SUS people and Dave Barker are working on it.

We will resume our work when TTs are fixed, and in the mean time we'll look at the IFO alignment.

We made one measurement using NanoScan by misaligning the 50% BS after the HWP to direct the  beam to the head. The BS and Nanoscan were approximately 8"x44" apart (give or take an inch).

These are just the numbers NanoScan software dumped. As was partially captured by https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=8437, our experience is that Nanoscan, ModeMaster (takeing the beam size at the head) and hand-driven knife edge agree with each other within 10%.

power before AOM :31.1mW 

after single pass: 24.1mW 77% single pass effiicency

after double pass: 20.45mW  66% double pass efficiency

The beam position on the iris after the retro reflecting mirror has not changed. 

I tuned the upper periscope mirror pitch, this brought the transmitted PD voltage back to 1 V.  

We have 5.8 mW in the ALS path before the Faraday, 5.33 mW after the Faraday, 4.3mW going towards the fiber, and 1.04 mW going towards the fiber launch PD (external on the fiber dist box).  

After 11 days of pumping the vertex volume - HAM2,3, BSC1,2,3, and the X manifold.

Alexa, Sheila, Kiwamu

The goal of the day was to get the retro-reflection from PRM all the way back to PSL. And this was achieved. We are ready for the HAM1 incursion.

This work involved:

• Restoration of the IMC alignment back to that established in this past Friday.
• Re-engagement of the ASC loops on IMC.
• Checking the Faraday clearance by looking at scattering light around the waveplate baffle at the entrance of the Faraday,
• Adjustment of the alignment of IM1 and 2 to get through the Faraday.
• Adjustment of the alignment of IM2 and IM3 to get the same spot position (a.k.a. IM4 trans) marked on the wall.
• Adjustment of the alignment of IM4 to get the same spot position (a.k.a. return beam) marked on the wall.
• Adjustment of the alignment of PRM to get the retro-reflection all the way back to PSL.
  • For getting the retro-reflection, we used the beam splitters that Paul installed for his Faraday loss measurement.
  • The PD for this retro-reflected light is now connected to the SPARE_10 lemo cable, so that one can see the signal at the outside.

In the process of aligning PRM, we looked at the in-vac WFS in HAM1 with a viewer and saw the reflection light hitting the WFSs. We didn't check the beam on the WFSs after obtaining the retro-reflection, but they should be pretty close to the good alignment. Then after obtaining the retroreflectin, we went to ISCT1 to see if we get some light on the table, but we didn't find it. Maybe it is blocked by an optic for some reason as we can see scattered light. So the first thing we should do before the incursion is to check the beam alignment in HAM1 and see if makes sense. It might be possible that the alignment in HAM1 is bad even though we have a retro-reflection back to PSL. In this case, we should steer IM1 and IM2 to change the rejection angle of the REFL beam while keeping the retro-reflection.

P.S. We left PSL in the commissioning mode. The IMC autolocker is running on opsws3. The attached is the alignment that we established. I tried steering the IM4 trans picomotor, but it seemed not moving at all.

Today, Jeff, Andres and I finished disassembling the lower structure and 4 lowest masses from the ETMy QUAD upper structure.  This involved pulling all of the reaction lacing cables up the chain.  As well, we had to cut the fibers off of the previously monolithic HIFOy masses in the suspension.  When Travis went to cut the first fiber out, the lower mass was apparently under some small load and the fiber broke it and it's adjascent fiber off.  We think there was still some load on the fibers even though all of the masses had been locked in place.  We raised the test mass before proceeding to cut the next 2 fibers out.  Jeff, Andres and I then split the chains and left the main chain resting on the Genie arms and the reaction chain on the 5-axis/scissor lift equipment.

After lunch, Angus and I pulled the PUM out of the suspension and canned it (Gerardo - we're missing a top o-ring plate in the empty can - so the canned pUM is missing it.  We need to steal one from the next can out there).  I then cleaned the lower sus via vacuum while Angus continued preps with Travis in the weld area.  We then stuffed the new PUM and got practice fibers loaded into the practice suspension for welding tomorrow.

I'm now out the rest of the week, but here is the sequence of tasks that need to happen next:

TUE AM - Gerardo / Travis pull the Test Mass, park the Main in the weld room, park the Genie under the reaction chain for added safety

TUE mid-AM - Travis / Angus / Alastair start practice welding (make sure to get panels in place)

TUE mid-AM - TCS peeps swap the ring heater (yes, likely in laser hazard, sorry)

TUE aft - finish practice weld

TUE aft - Gerardo / one of the weld crew stuff the new test mass

WED - set LS main mass DOFs and start real welds

Y'all already have mad skills, so smooth running and good luck to you!

Sensor's rotatable 2.75" CFF had a significant "ding" on knife edge -> don't have spare -> messaged with stone -> likely to be a leaker -> marked for leak check

- Cable routing in beer garden for OptLevs - Fil, Aaron
- Replacing sensor card on Aux Cart at EX - Gerardo, Kyle
- Tour for documentary - Mike L
- Viewport survey at EX - Hugh
- Commissioning work - Alexa, Kiwamu, Sheila
- Staging and preparing for fiber welding - Betsy, Travis, Agnes
- Working on quad at EY - Jeff Bartlett

The roofing membrane work is complete. All that remains is to complete the lightning protection system and install a few runs of downspout. Once we get some warmer weather I expect this work will be completed in a few days.

There were several conversations this morning WRT outstanding general INS tasks that remain to be worked. The tasks Bubba and I had in mind were grouting at HAM5/6, removing aLIGO HEPI components from HAM7/8/9/10, and removing aLIGO feedthroughs from HAM7/8/9/10. The grouting work would be very dirty and very close to the SRs so Michael decided against that. Of the two remaining activities, the feedthroughs seemed the easiest to start. In conjunction with that work, Apollo will replace all Al blanks on H2 chambers with conflat blanks. Scott and Tyler spent the afternoon gathering materials. 

All beam tube insulation has been removed. Enclosure has been nicely cleaned up.

(Kyle, Gerardo)
Replaced the dual pirani sensor card for aux pump cart #1, and started pumping BSC09 annulus.

Roughly 30 elk crossed route 10 a few hundred meters from the entrance to LHO this morning.  
Watch out while driving... cell photos attached.

The ref cav transmitted light kept decreasing over this weekend. I had to set the threshold further down to 0.3 yesterday while the nominal is 0.9. This needs an investigation at some point.

Sheila, Kiwamu, 

Today we realized that the centering on MC3 that we did on friday night resulted in a bad mode cleaner alingment.  We used DOF 4 to minimize the angle to length coupling of MC3, but this resulted in operating close to the edge of the osem range.  While Kiwamu and I were trying to align IM1+IM2 to get through the faradat this afternoon, the mode cleaner got into a state where MC3 was constantly tripping.  We plan to go back to the mode cleaner alignment as of friday afternoon, live with the clipping in the IM1 trans path and move on to aligning the IMs and PRM tomorow.  

The good news is: we know how to look through the veiwport and align the beams through the Faraday, and IM1+IM2 give us plenty of actuation range to do this.  

Our mistakes were:

The beams on the wall are IM4 trans, not IM2 trans.  The rumor I started that they were IM2 trans caused us to think we didn't have enough range on IM1 on friday, which is why we started the centering on MC3 in the first place. 

We centered on MC3 by introducing an offset to DOF4, which changes more than just the centering on MC3.  

We might want to measure the spot positions on all 3 MC mirrors and compare to Jax's measurement in alog 6676, to see if this makes sense. 

Just to note: on saturday Stefan and I realigned the IM1 trans path on IOT2L, when we revert the MC to friday afternoon we will have to realign that.  This afternoon I restored the PZT to where it was friday afternoon, and restored MC1 to where it was friday afternoon using the witness sensors.  After that we realigned the refl path on IOT2L roughly.  The next steps are to restore MC2+3 using the witness sensors, and fine tune the alignment on the refl WFS once the MC is locked.