Kyle, Gerardo  

We retested the feed-through flanges which had previously passed leak testing but which had since had their cable "back-shells" replaced ((12) cables on (6) 4.5" flanges).  We did this to verify that the act of disconnecting and reconnecting the cables required to replace the back-shells had not resulted in any "new" leaks -> We found no new leaks.  Indicated helium baseline remained ~6 x 10-10 torr*L/sec throughout testing. 

Next, we retested the 4.5" CF blank which had initially been found to leak at 1.1 x 10-7 torr*L/sec earlier but which had been tightened and found to be fixed (see earlier entries) -> No leaks 

Finally, we retested the known leaker (dual triax) and verified it to be leaking at 2 x 10-7 torr*L/sec (note: slight difference between current value and value previously reported is due to calibrating using a different source of calibration gas, external vs. internal cal-gas source).  

We plan on venting the YBM next week and to replace the leaking triax flange as well as reflanging the feedthrough suspected of having "bottomed-out" flange screws (see earlier entries).

A few views.

Of note, the eLIGO 25p connector looks a bit more solid for the metal flange on the airside.
The 3PinPwr connectors look to be the same ceramic style (photo2) but the spacing between the connectors are much closer on the aLIGO design.
The third image shows what I'm planning to use for Cable strain relief.  I need to add a couple more holes and widen the height of the shroud but I think that will work well.

We did many things, but the punch line is we seem to be at about or better than our tolerance.

We pushed the cube further to take out the gross misalignment, and then used an additional 50 gram trim mass.

After this, we put the table on the stops to fix the input aperture position and put the target on it. Jason's measurement showed that it is about 1mm off horizontally, which is very good.

Then we removed the aperture and backed off the stops so the entire thing floats freely and damped the vibration using BOSEM.

Jason was able to focus on the bottom periscope mirror. By panning the total station, he was able to measure the angle of the four edges of the mirror aperture:

Top: 1.319 mrad, Bottom: 1.363 mrad, Left: 1.993 mrad, Right: 1.867 mrad

Since it was absolutely impossible to eyeball the centering on the periscope mirror or on the table hole, I and Virginio calculated independently the centering on the periscope using Jason's numbers.

My script (preliminary) produced (-0.83mm, -0.41mm), which is good. Note that the requirement for the centering at the table hole (which is close enough to the periscope mirror) is 1mm.

Virginio's script (again preliminary) produced (-0.41, -0.14)mm, which is even better.

At this point we haven't reviewed the script of each other's, but it's very unlikely that both of us are grossly underestimating the centering error.

We asked Jason to look further down, but he can only go as far as the first steering mirror after the top periscope mirror, and there the view is already very dark even with Stinger flashlight.

There's no way he can look all the way down to the QPDs.

Also, the visible red laser from the total station becomes really faint on the ISC table and is unusable.

If we want to make another independent measurement to confirm the alignment, we need to use stronger IR laser.

For future, I think we need to make a thin target for the table hole. It should have a small 1mm-ish hole in the center which we can illuminate from the top, and scribed cross and bull's eye pattern which we can illuminate from the bottom.

If we make this out of thin aluminum disk. If we can make this less than 10 grams, judging from our experience of moving 50+ grams on the table, it would not tip the table that much.

- Stoneway visits for electrical work
- Apollo grouting input arm beam tubes
- TMS finishes rough alignment at EY
- Doug to teach Dan and Cheryl how to operate Total Station
- Leak-checking of vacuum feedthrus pending cabling work
- PSL: waiting for wind to die down before HVAC installation
- Apollo leak-check on crane

After making some measurements on the ISS, it has been set to run on PDB (normally on PDA). This shouldn't affect the laser.

Duct work for the make up air has been set, line sets for the interior AC units have been run. Cable tray work is ongoing.

The welders completed the move of the HEPI Tubing and we restarted the pumps and topped up the fluid.  We'll be in bleed mode for as long as allowable.  To be clear, the Actuators at the Piers remain isolated from the circulating fluid and therefore are not operational.

EricA/HughR

I've pushed an updated version of the h2iscey model, that includes some missing termination of unused channels.  I have also rebuilt and installed this model, both without issue:

controls@h2build ~ 0$ cd /opt/rtcds/lho/h2/rtbuild-2.4.1
controls@h2build rtbuild-2.4.1 0$ make h2iscey
command is make h2iscey
...
Successfully compiled
*********************
make succeeded
log file is /opt/rtcds/lho/h2/data/buildlog/h2iscey_2012_06_23_15:06:52
controls@h2build rtbuild-2.4.1 0$ make install-h2iscey
command is make install-h2iscey
...
make succeeded
log file is /opt/rtcds/lho/h2/data/buildlog/install-h2iscey_2012_19_23_15:19:33
controls@h2build rtbuild-2.4.1 0$

NOTE: I have not restarted the model.  I'll leave it to someone on site to restart the model.

Tediously, moanfully and slowly we make progress.

ISC table was rebalanced.

There was an excessive roll in the upper mass, which was fixed by using the slide mass at the top.

Left and right BOSEMs were too low (light 100% cut off), so they were brought up.

Side BOSEM was off-centered and (barely) touching, restricting the upward motion of the upper mass, and it was centered.

Face BOSEMs were centered and adjusted too.

After doing these, the center of the telescope input aperture didn't move much if any, but the yaw angle of the thing somehow got better (why?). Yesterday the laser beam injected from the total station was not hitting the secondary, but now it's hitting. We're still off in yaw and need to use the pusher to rotate the cube.

At the request of Ken Mailand, we also spent some time making measurement for the position of the ISC table in relation to the ISI table so Ken and Calum can understand what could have gone wrong between the cookie cutter and the TMS telescope.

We started to use BOSEM readings. At first nothing worked as burtrestore was not properly done. I think there was one reboot about two weeks ago where people didn't care to burtrestore h2sustmsyepics, and after yesterday's reboot Jim burtrestored to the morning of Feb/21, but of course that didn't work.

Anyway, after Jim burtrestored to a known good time (Feb/03 morning), BOSEMs started making sense.

We cannot burtrestore from the EY CDS workstation. Why?

We still haven't connected QPDs.

Attached are plots of dust counts > .5 microns.

The FMY medm values had not recovered properly from some frontend reboots.  The "h2susfmy_safe.snap" file was used in the  '/opt/rtcds/lho/h2/cds_user_apps/release/sus/h2/burtfiles/fmy/' directory.

New .ini files for H2SUSITMY and H2SUSETMY (added channels), restarted dc0 at 15:31 PST Feb. 22, 2012

Hugh, Corey, Hugo

Some of the CPS-targets of HAM-ISI Unit #2 are scratched. Scratching patterns suggest that damages were caused by the insertion of a Teflon shim to check the sensor-gaps, which was performed prior to disassembly/reassembly. This test was waived for the two latest units tested at LHO and should be avoided.

Some targets have dents. The origin of these dents remains unknown.

Damaged targets will be sent back for re-machining.

Freed up the TMS and balanced it.

It turned out that the height of the TMS was spot-on, but about 7mm off horizontally. What is the cookie cutter for, again?

Anyway, we pinned one corner of the cube, installed four temporary dog clamps with teflon tips, undid the real dogs until everything is loose, and used a pusher to tilt it.

After this adjustment, it was off by about 1mm in yaw, and still spot-on in pitch. We called it good.

Next, injecting the red visible laser beam from the total station, we can see that the angle is still far off in yaw (but pitch is OK).

We'll continue the angle adjustment today.

Attached are plots of dust counts > .5 microns. I have included a plot of H0:PEM-LVEA_DST15_MODE to show when the connections were lost due to this.

200W beam

Kyle, Gerardo, John  

Found gross leak on dual 3-pin actuator power feed-through on BSC8 (NW) -> Vented YBM, replaced leaker with one that was bench tested and found not to leak.  As found, in-vacuum cables connectors were not screwed to feed-through connectors -> NOTE: flange-to-flange gap is uniform but conflat joint is not "metal-to-metal".  Seems as if flange bolts are bottomed out in blind holes, tapped holes may be too shallow on this one flange(?) -> Pumping YBM overnight with purge/vent valve "cracked" open.