Plot attached.

Durring the earth quake this morning I went out to End Y to work on the IR path, using the small amount of green light reflected into that path.  As Keita said, the beam divereter is open when the medm screen indicates that it is closed.  I moved the top periscope mirror down several inches, and moved the whole periscope about  inch closer to the corner station.  I had to use the third actuator to get a larger angle on bothof he periscope mirrors, this was the same situation as with the X end table and is because the beam comes out of the chamber at an angle.  The path is roughly aligned to the PD and camera, but will need to be tweaked up when we can align the Y arm and use IR.  I also replaced the camera cable with the one that Aaron and Keita left, although it is not labeled yet, checked for a signal, and connected it to input 2 on the video box (I also moved the cable for the ETM to input 1 following Fil's instructions).  

These are run from the vacuum feedthru up onto the Optical Table.  SUS will connect to SUS etc.  SUS has serial numbers and will ICS those and mate accordingly.

All the BSC-ISI tripped, starting at 1083604427, except ETMX which was on High Blends (no T240s in the loops)

I found stage 2 of the ISI at end X tripped this morning. Both GS13 and ACT were indicated as first triggers. Plots are attached.

SR2 is aligned.

SR3 was installed last night. It will be clamped down and wired today.

Betsy is working on baffle installation in HAM4. There are issues with the cookie cutters.

No TCS projection likely today. This is Matt's last day. He would like laser hazard ASAP.

WFS work is on hold.

Staging the ITM in the beer garden is on hold.

A faulty ESD cable at end X was found and fixed yesterday. Work continues today.

Work on 3rd IFO assembly continues in the staging building.

Joe D. wants to get access to a box at mid Y. This will require craning another box out of the way.

(David H, Matt H)

So a silly assumption that I made has caused me to make what I consider a rookie mistake and thus we are having a few problems with TCSx alignment.

The story thus far. We are trying to set the beam height to 4 inches in height to be flat across the table. This was accomplished up to the polarisers after the Beckhoff controlled waveplate (see layout) and for the ISS photodiode alignment, the quadrant detectors. Now the silly assumption I made (and I kick myself as it was hammered home to me all throughout my phd to never assume anything, and thats been my mantra at LIGO, until this one time...and its bitten me..*sigh*) is that because the two polarisers and the flipper mirror (which is next in line for the central heating beam path) were all in fixed mounts that if the beam coming onto them was parallel with the table at 4 inches, then the beam after it had reflected off all these optics would still be parallel with the table at 4 inches.

With this assumed knoweldge and because the optics had all been laid out in roughly the right position in advance making the table cluttered (no excuse I know), to check if each mirror, beamsplitter, etc I used in the path after these optics  was projecting the beam correctly I placed a target as far away as I could and projected the beam onto a target and altered the vertical adjustment of each mount until the beam came to 4 inches on the target. Now this technique only works if the beam incident on the optic you are testing is horizontal with the table, if its not you are just setting the beam height to be 4 inches at that one spot and the beam path could actually be going up and down. What I should of done is what I always normally do with optics and check the beam height up close and far away and see that it stays at the same height...lesson learned....*sigh*.

I had aligned the central heating path with a little trouble but got a solution so that the beam path would go be able to go through the irises we had marked as our optical axis to get the beam up the periscope and into the chamber and onto the cp correctly (this we had done the other day with the HeNe beam....Im sorry on the layout I forgot to mark the iris location but they are between the last gold mirror (at the top of the page) and the periscope). The trouble came when we tried to get the annular heating path to also go through these irises, we couldnt find a solution to do so. David came up with the brilliant solution to shine a HeNe through the irises the other way and see what the beam path should roughly be for the annular heating. What we found is that the HeNe beam shot over the top of the mirrors used to steer the annular heating beam onto the beamsplitter meaning no solution was in fact possible with what I had laid out. 

So whats the problem. The problem is in my assumption. With everything in its current layout, we used a combination of CO2 beam and HeNe beam to look at what the reflections of the polarisers and optics in the flipper mirrors are doing. What we found is that each of the two polarisers after the HWP both kick the beam up, as does the first flipper mirror after the polarisers, and the 2nd flipper mirror kicks the beam down (we are talking numbers like 1/4 inch over say 15-20 inches). I checked the two flipper mirrors set aside for the TCSy table and they both kick the beam up as well.

This did not bite us with the central heating beam (for the moment, it would of when went to put the mask in and wondered why the beam was not at 4 inches) as the otics are all nice and close to each other, so even if the beam is going up and down a bit, they still hit roughly the center of the optics and can find a solution to get the beam through the irises we set to align the beam heading  towards the periscope. It turns out that the optical beam path off the second flipper mirror towards the beamsplitter that recombines the central heating and the annular beam path, is on a downwards slope (because of the flippers/polarisers throwing us out of plane). It bites us for the annular path because its such a long lever arm that to match the optical path set by the central heating optics we would need such a steep angle of the beam that the mirrors we used to steer the annular path onto the beamsplitter cant provide this.

Sooooo whats the solution. Well first...never make assumptions again. But in all seriousness there are solutions and I throw out options without having really thought about it or having discussed it with the TCS folk like Aidan. Options include, using flipper mirrors (like those I believe that were used in eLIGO) that have vertical adjustment so that we can correct vertical alignment, putting in an extra mirror in a bow tie type arrangement to try to correct out the vertical kick up or down, change the layout (but keep the length the same) of the annular path so that at least one of the steering mirrors is closer to the second flipper and so we can try to match the downward trajectory of the beam path set by the second flipper for the central heating route. We could try to remount the polarisers better. Again this is all just being thrown out there for now.

Hopefully you arent all thoroughly confused by now, and I really am sorry we didnt catch this earlier. Kicking myself all night for such a rookie error and feeling wasted peoples time. If nothing else its given us fair warning to look out for this on TCSy and when we do the two livingston tables, so it actually could be a time saver by finding this problem now on the first table and coming up with a solution.

model restarts logged for Wed 07/May/2014
2014_05_07 01:02 h1fw0
2014_05_07 05:53 h1fw0
2014_05_07 08:45 h1fw0
2014_05_07 10:11 h1nds0
2014_05_07 14:46 h1fw0

Minute trend offloading caused the unexpected h1fw0 restarts, completion of this work required the later restarts.

I launched TF measurements on both TMSX and TMSY for Anaud at around 3:43 AM local.

Kiwamu, Stefan

The story of the evening is short:
 - H1:ALS-C_DIFF_PLL_GAIN was accidental increased to 26dB. Up there the PLL oscillates - the gain has to be 6dB.
 - The power on the ETMX UIM coil driver was off - it should be on.
 - The ESD was in a dead state - we had to recycle the power to get it back.
 - Fixing these things took a very short time - its finding them that took all evening...

 - Before starting to chase these 3 needles in the haystack we also updated the L3 inverse plant filters to match the 0.5Hz resonance of the upper stages exactly. This should guarantee a stable behaviour of the blend filters at 0.5ish Hz.

 - Finally we measured the gain ratio between the TOP/UIM combined actuator and the TST actuator at two frequencies:
           TST/(TOP&UIM) ratio
    2.5Hz      2.9
    4.0Hz      1.9 
i.e. the TST drive was  2 to 3 times stronger than the TOP/UIM actuator. We set the TST gain to 0.5.

 - When we finally tried this at the end of the evening, and got the UGF to 1.2Hz. This was done with two additional p5z50 roll-offs.
 - The resulting coil output spectra are attached.

 - Next Kiwamu put in a boost at low frequency to suppress some noise - we got an RMS of ~100Hz in infrared.
 - In this configuration we are limited by the ESD around 3Hz and the UIM drive around 10Hz in about equal amounts.
    Ideas:
      - Get a factor of two in ESD range by using additional drive offset and linearisation
      - Get a factor of two in total range by using ETMY too.
      - Fine-tune the the UIM/TST blend filters with the measured coil noise in mind.
      - Resurrect PUM drive around 10Hz?
      - What is the diff noise from 3hz to 10Hz?

WP 4615 is now complete.  Raw minute trend files that were on the nearly full SSD raid array on h1fw0 have been copied to the SATAboy hard drive array, verified to ensure the copy is complete and accurate, and then the old raw minute trend files removed from the SSD.  New raw minute trend files are being written to the SSD array.  Dataviewer was used to ensure that h1nds0 could serve data across the boundary between old and new files.

Since Stefan and Sheila weren't able to find the IR beam in ISCTEY the other day, I went there and looked inside BSC10 through the viewport.

The first thing was that the logic for open/close of the beam diverter is wrong AGAIN. When it's "closed" the beam comes to ISCTEY, when "open" the beam is cut by the beam diverter.

Second, I looked at the green beam retro reflected by ETMY leaking to the IR path, and was able to locate the beam in ISCTEY once the beam diverter state was set correctly ("closed"), but the beam passes about 6" below the periscope mirror (first picture) and hits the ISCT panel on the opposite side. We need to lower the periscope mirror by about 7". (Green leakage beam does not exactly follow the IR path because of the dispersion and the wedge of ETM, but it should be close enough to find the IR beam.) This could be done at any convenient time (maintenance, earthquake, ...).

Third, Aaron brought a good replacement cable for ISCTEY camera, we tested and it was good, but I didn't install it (I need to leave now), it's just sitting on the ISCTEY table. This camera is not useful until the periscope mirror is lowered anyway.

The second picture shows how high this periscope is as of now relative to the green injection periscope.

Kiwamu and Dave

After the inclusion of the ADS (Alignment Dither System) part into ASC_MASTER.mdl the h1asc model would not compile. I spent some time this afternoon investigating this problem. I noticed that the rtdemod parts with were listed in the rcg error log all shared a from/goto tag call SPOP18 which was relatively new. When I removed these tags (10 receiver tags) and replaced with straight through connectors the model compiled.

On futher testing, I found the the addition of any more tags (even a single goto/from pair) caused the compile to fail. Perhaps we are seeing an internal part/tag limit.

I've attached the before and after pictures of the relevant part of ASC-ADS, the before has the yellow SPOP18 tags.

I've only performed a "make h1asc" at this point, if we choose to run this model a "make install-h1asc" will be needed. The ASC_MASTER was linking to an ASC_MASTERr7418.mdl file for the ADS block, I have broken this link and ingested ADS into the master model.

Andres, Margo, & Jeff

   We have moved H1-SR3 into HMA5. The suspension is positioned on the ISI but only held down with 4 dog clamps. We will continue the install process tomorrow when the LVEA is laser safe.

(Alexa, Daniel)

Continuing yesterdays work we locked on PRX and installed the beampspitter in the POP path in front of POPAIR_A. The beam was very weak and we had some fun aligning it. We needed an additional lens (ROC 500mm) to keep the beam small. After the beam combiner we measured 170nW of power. Another short focal length lens was installed after the combiner to focus the beam down. We are still missing a photodetector.

Jim reported some issues on ETMY HEPI yesterday https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=11618

Turns out that the position loops used were adding extra amplification at 10Hz (a 10Hz already amplified by the pier on this chamber). This was causing the HEPI to go unstable, dragging the ISI with it.

I switched to the controllers installed in FM2&FM3 (Cont_2), which are more generic, less aggressive loops. It works just fine.

ETMY chamber is used by the commissioners right now, but as soon as I have a chance I'll modified the design of the Cont_1 loops.