kyle.ryan@LIGO.ORG - posted 12:58, Tuesday 10 December 2013 (8892)
Began pumping X-end
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:
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.
Arnaud and Kiwamu
We looked back the past data of the MC3 OSEMs. We found that the IOP DACkill had been triggered by MC3_T3 OSEM as it was hitting the open light value of 22000.
On Friday:
- Apollo finished staging the cleanrooms/garb/work tables/sticky mats, etc.
- Apollo did thorough cleaning of the cleanrooms/receivings/VEA.
- Travis and I staged the EQ needed to remove the lower structure (Ergo arm/pump/monitor box, scissor lift with 5-axis table, stool, tools, LSAT)
- We transported the new PUM, the new Test Mass, and an empty cake tin to Ex.
- Travis started staging the welding EQ - ran into a snag with missing chiller hose fittings (!)
- I started prepping the lower structure for removal (dropped the x-braces, vib absorbers, wedges, and most of the bolts holding the sleeve up). There was a reason the procedures always called for SUS work to take place prior to TMS install. Removing the LS with the TMS in place is a challenge.
It will take Angus, Travis, me, and Jeff or Andres all of Monday to get to the point where we are swapping in the new optics on Tuesday morning. Slow as she goes.
Sheila, Kiwamu, Stefan, Alexa, Arnaud, keita.
Today we started out by projecting the spot on IM2 trans on the wall, and saw that it was so high that we were unable to steer it to the reference (from Oct 4th 2013) with our range (after the coil driver change). After some investigation, we set things back to what we thik the alignment was in late september, using both HEPI and using the BOSEM readbacks for the suspension alingments. After that we saw that the spot was still too high on the wall.
We then started measuring the beam centering using the A2L coupling of MC3. We used the A2L coupling to adjust the offset in the uncontrolled DOF (DOF4 pitch). We have reduced the coupling by a factor of 10.
As a result of the spot position adjustment on MC3, the IM1 trans light moved by this much:
This is a picture of the IM1 trans -- the camera itself is on IOT2L -- and the red sharpie mark at the center of the monitor was for the spot position recorded in this morning. So the beam spot went upward on the monitor i.e. the beam went down because the camera view is up side down. Interestingly, the beam shape improved and becoming more round-ish, indicating we are getting less clipped. Indeed, H1:IMC-TRANS went up from 800 to approximately 1100. Good.
Below is a summary of the available controls on SEI platforms, for PRMI. Platforms should run under their preferred configuration at all time.
HAM1:
HAM2:
HAM3:
Note: The HEPI-BS position loops are in the second set of filter banks. One should use the isolate BS lv2 command button, instead of lv1, for this chamber only.
work of warning - the level 2 filters attempt to turn on Filter modules 2 and 3, and module 9 for boost (level 1 uses FM1 for isolation turn on + FM 10 for boost) one should check that the boost module is OK. It used to be true that attempting to turn on an empty module (FM3) makes no difference, but we should check... -Brian
[Jeff B, Andres R, Rich A, Jeff L, Koji A]
We successfully resolved the grouding issue of the OMC preamps, thanks to the help provided from Peter K, Rick S, and Betsy B
for the necessary isulating materials. Here is the note for ourselves and someone who may work on this insulation for L1 and 3IFO.
The grounding of the ISC cables were caused by the mounting of the preamps (attached figrue, left). The PEEK washers
were used to isolate the bracket from the structure. In order to fit the wahsers, we had to trim them (only for the outer one) with crimpers.
In order to isolate the 1/4-20 screws from the hole walls, we used Kapton tubes. Since the diameter of the tube was too big
for the hole, we had to open the tube and trim it to reduce the number of turns. In addition, the metal washers should have
been removed as they sneakily caused the grounding with the preamp.
Additional note (Dec 8)
The preamps are touching the cable for the PZT signals. Therefore the installation of the isolation kit should be done
without removing the adapter plate in order to avoid misalignment of the glass breadboard.
This can be done by installing the isolation kit one side at a time:
1. Loosen the two 1/4-20 caps
2. Remove one of the screws while the adapter plate was kept at the installed position.
3. Insert an unmodified PEEK washer between the SUS structure and the adapter plate.
4. Put a trimmed PEEK washer on a screw. Roll a kapton tube around the screw.
5. Insert the screw combo into the screw hole.
6. Turn the inserted screw (not fully)
7. Repeat 2 to 6 for the other screw
8. Tighten the two screw.
9. Check the isolation between the preamp housings and the SUS structure.
In this configuration, I measured ~3.1mW at the input of the ALS fiber distribution and 100uW at the MSR.
and the end station we see 40 uW coming out of the fiber, not really enough.