To follow up on the "Apparent Y-1 leak" entry made last night: Today I found a very large (~1x10-4 torr*L/sec) air leak on the 1.33" conflat flange at the valve body/annulus piping interface on the south side of GV9. I also found a lesser (~3x10-7 torr*L/sec) leak on the 2 3/4" conflat flange located on the gate side of the 1.5" all-metal gate annulus isolation valve -> *Hard-Closed GV9 *Isolated and vented gate annulus piping *Replace gasket on leaking 1.33" conflat joint *Cinched-up flange fasteners on leaking 2 3/4" conflat joint *Pumped and recombined vented volume to rest of annulus *Opened GV9 I am leaving the leak detector connected and valved-in to GV9's annulus system overnight tonight. I will do some sensitive leak checking tomorrow. NOTE TO ALL We have many original "legacy" bolted joints on the vacuum system throughout the site. Though these have stood the test of time up to this point, they may still be vulnerable to being mechanically or thermally exercised, bumped, flexed and the like. Please be cautious and conciensus when your work requires contacting bolted vacuum joint/flanges.
Work on the roof was finished today in preparation of the HVAC people coming in tomorrow to set up ducting. The exterior floating wall was also worked on, using 1" drywall screws to prevent contact between the screw and the inner layer of sheetrock. Tomorrow they plan on finishing the interior insulation and starting work on the HVAC system.
Dust counts remain normal, although there were a few brief periods, no longer than 5 minutes, where counts exceeded 20,000 at 0.5 microns. This does not appear to have affected the cleaning by HAM12.
BSCISI #1
Jim is working on prep work for getting parts (mainly hardware such as helicoils, bolts, etc.) Class-A-ed and ready for upcoming work.
BSC Work Area Clean Up
More Small Outer Walls Installed. The Horizontal GS13 Walls were pre-assembled and rest on the Optics Table. We do not have Flexure Access Outer Walls (D071058) available; Hugh assures me that some are currently in a Bake Oven now and could be available in a few days.
Weights have been put on the Walls & on the Optics Table. Now that the innards of HAMISI#3 are being cleared away from both SEI cleanrooms, more and more space is being created for upcoming BSC work!
To confirm modeling, we weighed the Assembled Stage0. The 1250#s does not include the Spring posts which some might include in the assembly but we didn't have them mounted. It does include all the bolts clamping the plates together and all helicoils and dowel pins. It also includes the three 1/2-13 lifting eyebolts. The design weight is 1242 so we are right there.
[Corey, Hugh, Jim, Stephany]
BSC#1 Assembly Work
More helicoils were installed on the Optics Table (until we discovered we were almost out of helicoils). The Stage0 Base was lifted off the tested so it could be weighed (this was done with a load cell via the forklift).
BSC Work Area Clean Up (aka HAMISI#3 Work)
Made first attempt at installing the Vertical GS13's & two thirds of their Outer Walls, and then discovered the feed-thrus did not line up with the hole in the Stage-1 floor! Basically, procedure (E0900216-v5) uses a drawing to show how to orient/install the vertical GS-13, and this drawing is 120 degrees off. Looking from the top, the Vert GS13 should actually be 120deg counterclockwise from how it is displayed in the photo (figure is attached). So most of the day was devoted to installing the GS13/Walls, uninstalling, and then re-installing. In all the hub bub, I failed to note the Serial Numbers for the now-covered GS13's. I did get one of them though. V2 is S/N 163.
One More HAMISI Procedure (E0900216) Note
For installing the Outer Walls, the procedure does not make mention of torquing the 120deg brackets during installation (this is in Sec. 4.34). This could be an easy thing to forget during installation with all the bolts to be torqued.
I noticed that the Y-1 module pressure was in the upper 10-7 torr (Y-mid end) range as I was preparing to leave tonight!!!!! -> I notified John W. and went to the Y-mid to investigate: *GV10 and GV9 annulus pressures ~normal *CP3 level normal *Started QDP80 pump and connected it to the closed purge/vent valve (Y-mid MTP decoupled to premit retraction of spool bellows for BSC6 removal) in preparation to rough-down BSC6 volume (currently vented) *combined GV10 gate annulus volume to rest of annulus piping (i.e. pumped GV10 gate annulus) *Soft-closed GV9 John, Bubba, Scotty and Robert S. arrive *Begin pumping down BSC6 volume with QDP80 *Tightend many of the suspect-looking "gappy" conflat flanges, tapped joints, wiggled external piping etc. *Opened GV9 *Closed Y-mid vent/purge valve but leaving QDP80 running No conclusion at this time. John W. confirms that he is able to view the site from home. John W. and I (maybe Mike L.) will monitor off and on from home during the night. PT244 @ 1.08 x 10-6 torr as of 2105 hrs. local
Work was started on the interior insulation. Contractors also started work on the floating outer wall but we ran into problems with the drywall screws being too long and touching the inner layer of drywall. They will continue tomorrow with shorter screws.
Dust counts remain normal
Usual Tuesday deliveries. Work continues on H2 PSL enclosure and chamber cleaning tests. Dust monitor trends attached for 0730-0430 local time, same locations as previous entries.
Marielle and Margot are visiting this week to bond the first test mass, the one arm ITM. Pictures are of the the optic with First Contact applied to the HR surface (by Margot yesterday), and of Marielle and Gerardo using the Romer CMM Arm to measure the thickness of the optic in a few places (verifying wedge, etc, in prep for locating the ears for bonding).
Ran well ump to fill well tank.
[Corey, Jeff, Jim, Stephany]
BSC#1 Assembly Work
Lots of shuffling took place today as plates were moved within the Staging Bldg and from the Vacuum Prep Warehouse.
Helicoiling and dowel pins were finished off on the Stage0 Top Plate. The Top Plate was then installed & torqued onto the Bottom Plate.
The Optics Table was brought onto the Granite Table and now helicoiling begins!
BSC Work Area Space Creation
This section covers work to reassemble HAMISI#3 (i.e. clearing shelf space for upcoming BSC work).
All of the Sensor Assemblies were installed. It was determined earlier that two of the Sensors for #3 were bad, so new ones were swapped in for #3. The new Sensors are S/N# 12029--->H3 & S/N# 12040--->V3.
During disassembly it was noticed that the small screws in the cable plugs which connect to the GS13 looked pretty damaged (their threads were really eaten up during assembly). It was decided we don't want to use these screws, and want to just plug in the connectors. But to do this, the damaged screws have to be pulled out because they don't allow the plugs to be connected. This was done for all (6) plugs.
All of the Horizontal GS13's were installed.
Note On Broken Tangs:
A few times during the reassembly of #3, rogue broken tangs have been found on several occasions (i.e. when you're installing a part, one finds that a bolt won't screw in---usually damaging the bolt). This has happened while installing an Actuator and while installing a GS13. So, eventhough we may be thorough, not all broken tangs are being accounted for.
Today the contractors installed insulation on the roof, later covering this with another layer of sheetrock. Aluminum standoffs were also installed on the 4 sides of the building - the floating exterior wall will attach to these.
As Dani mentioned, dust levels remain normal. One week trend is attached.
A MicroVac Portable ULPA Cleanroom Vacuum/Blower was purchased from Terra Universal. After Class B'ing a TFE hose, we confirmed that particle counts coming out of the exhaust and through the TFE hose were near zero (after making sure that surrounding dust wasn't being picked up and slewing the counts). Friday, we attempted to take some video/pictures of the blower hose blowing off particulate collected on a tabled QUAD UIM subassembly (see attached pictures). The field of view of the surface in the video is on the order of a few square inches.
A different round of blowing in a different location of a UIM.
It's a bit difficult to quantify how much particulate is being removed, but it is clear from the photos/video that a significant portion of the macroscopic stuff is being removed.
On several occasions I have set up seismometers on a building slab and on the ground near the slab and found that the slab follows the ground below a few Hz. However, I don’t think that I have previously put these results in the log. Recently Jan Harms and I were making Newtonian-noise related measurements and set up seismometers at the locations indicated on the attached plan of the corner station. The top plots in the figures X,Y and Z show calibrated velocity spectra for the X, Y and Z axes (directions indicated on the plan) for seismometers at locations indicated by arrows on the plan in colors matching the spectrum trace colors. The lower plots in each figure show coherence between the seismometer on the slab edge and the one 3.5 meters away, off of the slab in the gravel (RED). For comparison, the figures also show (BLACK) coherence with the seismometer that is 3.5 m in the opposite direction on the slab. Because we used only 2 seismometers, the black traces were taken at a different time. Coherence between the slab-edge seismometer and the off-slab seismometer drops faster with frequency than for the slab-edge and the other seismometer on the slab. The frequency at which coherence drops off between the slab-edge and the other on-slab seismometer at a distance of 3.5m away, is typical for 3.5m spacing, even at the center of the slab, and does not result from one of the seismometers being at the edge of the slab. The drops in coherence in the 1 Hz region, where the velocity is lowest, are also present in spectra from the huddled seismometers, indicating that a significant fraction of the signals in these regions are due to electronic noise. The black traces were made at lower resolution than the other traces and so do not extend down to the lower frequencies. The on-slab and off-slab spectra are very similar and the coherence is high below about 3 Hz in X, 5 hz in Y, and 8 Hz in Z. For fundamental Rayleigh waves, the wavelengths at these cutoff frequencies are thought to be of order 100 meters, based on propagation velocity measurements. Robert S., Jan H.
Last week we mounted the H2 iLIGO PSL table on a new leg system for aLIGO, discussed here. Our design philosophy was to minimize RMS motion in the aLIGO band by raising the table sway resonances from iLIGO’s 20 Hz to about 100 Hz, and the vertical bounce on the legs from the 40-60 Hz region to about 200 Hz. We did not want to raise the resonances much higher, because they would overlap with the periscope resonance. We chose not to float the table because the system we have experience with only controls 3 degrees of freedom and it increases low frequency motion in the 1 Hz region and below. Figures 1 and 2 show displacement spectra and RMS from accelerometers mounted on the H1 (iLIGO) table (red), and the H2 aLIGO table (blue) for comparable locations near the periscope position, taken at the same time, and a spectrum from the floor near the H2 table, taken at a slightly different time (black). Clean rooms were off for these spectra. The lowest of the sway resonances of the new table is at about 95 Hz, not quite 100 Hz, but acceptable, and the bounce mode is at about 200 Hz. The RMS motion of the new H2 aLIGO table above 10 Hz is about 20% greater than the rms for the black floor trace, while the RMS motion of the iLIGO H1 table is 730% greater. These results were comparable with those from the first installation, made at LLO, discussed here. Robert Schofield, Rick Savage, Michael Rodruck, Mark Dodson