Carolyn P., Cheryl V., Jodi F., Michael L., Patrick T., Rodney H., Zack H.

Yesterday the mid X (BSC 5) test mass was removed separately from the LOS and stored in a "cake tin". The "cake tin" was wrapped in foil and put on a cart in the back of the optics lab in class A storage. Particle tape samples were taken at four spots in BSC 5.

Carolyn P., Jodi F., Mark H., Matt E., Patrick T., Rodney H., Zack H.

Today we removed all the remaining hardware except for the isolation stack itself. This included the counter weights, telescope, OSEM connector and LOS. The OSEM cable was cut to remove it. The telescope and LOS are wrapped in foil on a table in mid X.

While un-bagging Class-A BSC hardware, I inadvertantly mixed some regular dowel pins with specially-machined Undersized dowel pins (D1100684); these were 1/8" pins, but I can't remember whether they were the 1 1/8" or 1 1/2" length.  After I did this, I measured thickness of pins, but couldn't tell difference; will give this another try.

Other undersized pins have been kept in their Al pouches and are grouped together in the same container.

Condensate pumps for the air conditioner units were added today. More electrical work as well.

(Corey, Eric, Jeff, Jim)

Continued to do what was needed to fascilitate BSC Assembly.  This occurred mainly on two fronts (with a third attack at the end of the day).

Hunt For Missing Hardware

Decided to go through all the class-A-ed BSC Hardware.  This yielded some missing washers.  Since some SUS hardware turned out to be in an SEI bag, Jeff B. scoured SUS hardware and found some bolts for us.  Now we are down to just two missing pieces of hardware:  3/8-16 x 2 1/4" & 3/8-16 x 2 3/4" SHCS. 

Filled up most of our empty Cleanroom racks with all kinds of hardware today (still have a few bags to forage through upstairs).  For today, roughly 12 man-hours was devoted to searching for missing parts.  

Clean & Bake Assistance

To help get some of our plates through the process, some manpower was used to help out at the VPW.

Optics Table Flipper & Reaming Hardware

This stuff was recently Class-B-ed.  The SEI team is checking for fit as I type.

Rodney, Zak, Kyle, Jodi

LOS/stack extraction at MX has been going on since 1:00.
Further preparations for the MY BSC move.
Work on air conditioning and plumbing of coolant lines for the H2PSL chamber.
Modular building continues to settle into place.

Air conditioner units were installed inside the PSL enclosure. They are hanging from threaded rods, suspended from the roof. The rods themselves are sitting on rubber machine mounts to isolate the units from the enclosure. Electrical conduit lines were installed as well.

Leaving aux. turbo pump cart running and valved-in to GV10 annulus (known leak to annulus from BSC6 side of GV10)

(Corey, Jeff, Jim, Mitch)

Workspace Converted From HAM -> BSC

Over the last 3-4 weeks, the SEI Cleanrooms were cleared of HAMISI parts/hardware/tooling to make room for BSC work (this involved TONS of wrap/bag/tag & organizing).

Stage2:  Optics Table

Helicoils were completed last week (installation & tang-breaking) on the bottom-part of the Optics Table.  We are now waiting for fixturing to flip the Table over.  We will then install the Top-part of of the Optics Table

Subassembly Work Begins:  Enter Actuators & Lockers

Parts and hardware for the Actuators and Lockers have been unwrapped and staged in our Cleanroom racks.  Have begun helicoiling parts for the Large Actuator.  A few issues:  5/16-24 helicoils were inadvertantly installed on parts.  The correct 5/16-18 helicoils are being installed---a first fit-check shows that the bolts are really tight in these helicoiled holes.  We do not have a tool for installing #10-32 helicoils--it is on order.

This activity has enlightened us to the complexity of keeping track of hardware, and the importance of bagging/tagging parts correctly (and also paying attention to the names written on bags).  We are missing a couple of items, but we are addressing these issues as we go.

Stage0 Work

- Blade Posts are loosely installed (still waiting on big 1/2" socket to torque down bolts). 

- Torqued down Stage0 (wrench-tight) to the Test Stand via threaded rods/nuts (note:  one of the nuts was not installed because the threaded rod had bad threads).

- Level of Stage0 was checked---it is level to within 0.005"

HAMISI#3:  Moving Out

It has been decided we will postpone testing on this Assy.  (So, we'll need to put a few days into removing GS13s, payload, cabling, etc. on this Assembly.  It will eventually be pulled out and put into a storage container---once the container is modified for use).

Throughout the day:
HEPI post install prep on HAM 7
HEPI pier install on BSC 4
Ski to outbuildings to turn fans off

10:20 - kyle to vent x-mid

11:00 – contractors here to work on modular building

11:03 – contractors to work on H2 PSL room

~2:00 - Filiberto replacing network cable in LVEA

~3:00 – Swageloc order for Hugh arrives

Changed pre filters and greased fans in the out buildings

Finished attaching the support brackets on BSC 4. The old iLIGO stack on the SE corner was cleared out. The SE pier is far enough out of center from the crossbeam that the HEPI frame would have interfered with the side clamp. Another hole was drilled to allow the clamp clearance (photo 1).

Holes were drilled in the enclosure roof for bolting the air conditioner units. 1-1/4" PVC pipe was set inside the holes and caulked into place. Outside the LVEA, the compressers were set into place. On Monday the air conditioner units will be installed in the enclosure.

Dust counts were elevated later in the day, with counts above 5000 at 0.5 micron, but the HAM7/8 surveying work was near the dust monitor, so the increase in counts may have been due to people standing nearby.

• Spool pieces arrived for MY
• H2 electronics building arrived (both halves)
• PSL enclosure construction ongoing
• Survey work at HAM7 and HAM8
• H2adcumy went out of sync again and had to powercycle it to bring it back up

I will be restarting apache to enable a minor configuration change.  I will do this at 10:30am Pacific on Saturday 7 May 2011.  The aLOG will be unavailable for seconds during that time period.  As always it is a good idea to save any pending entries to draft format before then.

There were three pressure spikes in the y-arm beam tube last week, on 4/28, 4/29, and 5/1. It's hard to tell if the pressure is coming back down, but it is currently about twice as high as it was 2 weeks ago. Kyle is aware of this - there is a small leak, and the spikes are due to the ion pump voltages increasing to pump out the leak.

We tuned the HEPI pump controller that will regulate the pump speed such that the pressure drop between the chamber inlet manifold and the chamber outlet manifold stays constant. Since there is no chamber hooked up, we controlled the pressure at sensor 4 (after 3 accumulators) on the manifold.
We identified the pump dynamic using a step response. Next, we approximated the pump with a simple model. Then, we tweaked the parameters of the controller using the model. Finally, we measured the closed loop response.
In attachment, you will find:
-	Amplitude spectral density of pressure at sensor 1 (after 1 accumulator) and sensor 4 (after 3 accumulators) for different revolution speeds of the pump.
-	Times series (Step response: Simulations vs measurements)
-	Bode plot (Pump, Open Loop, Closed Loop …). UUG=4.5mHz – Phase margin 60 deg.