Here are the two relevant pumpdowns underway. BSC8 (LVEA) has been under vacuum for 20 days. BSC6 at ENDY has been pumping only one day.

For comparison a 1999 pumpdown is also attached.

I will include log-log plots in a seperate alog entry.

Jonathan B.'s ops summary yesterday accurately described the status of the transit event through 18:00.  We caught a break, however, and obtained unobstructed views during the span between 18:30 and 20:30.  The attachment shows solar scope-meister Greg Mendell assisting some guests.  Roughly 150 community members attended.  Many came late in the day as the western sky cleared.   

Bubba Gately took some nice shots of the BSC1 stack extraction that show the relationship between the piers, the crossbeams, the support tubes and the stack.  View the collection in ResourceSpace. 

Thanks to the Apollo crew-Zack MarkL Caleb & Randy

No issues.  The Support Table slipped right out and the stack is mostly separated and headed to the recycler.  That is all the iLIGO stacks from the LVEA, just the two H1 ETMs remain.

- Cheryl, Mark, Zack, Mick, Chris, other support from Apollo

The iLigo H1 ITMY was removed from BSC1 yesterday.  The operation went without any major glitches.  The minor glitch was that the adaptor plate was no where to be found, so we used 3 dog clamps to bridge the gap between the top of the lift table and the base of the optics cage, which worked well.

The optic/cage combo is in the OSB optics lab, on the table with other deinstalled optics.

I built the IOP models for the following front ends: h1seih16, h1seih23, h1sush2a, h1sush2b. Unfortunately when starting these new front ends, the DAQ data from the PSL system was corrupted for several minutes at a time until we restored the H1 DAQ. For tonight we have turned off all the new front ends and are just running the h1psl0 system on H1. Only the PSL DAQ data was corrupted, the front end models themselves were not affected.

The IO Chassis for these front ends are being constructed in the H1 EE room. A timing fanout was installed which runs off the new H1 timing master in the MSR (h1psl0 still runs from the H2 master).

The latest change to h2susb78 (FMY front end) was to swap out the one-stop PCI bus extender fiber optics cable between the IO Chassis and the computer. The IOP was restarted at noon, it is still running after 10.75 hrs.

Attached are plots of dust counts > .5 microns.

- BSC1: moving garbing room, setting up lazy susan. Cheryl de-installed ITMY, preparing it to be sent to KAGRA. ICC will commence from north side of biergarten.
- BSC6: Long pump-down begins today, with Gerardo leading.
- Praxair delivery for CP6 and CP8.
- Electrical contractor working on DC power supplies at EY.
- FMY electronics still misbehaving...Richard addressing.
- Apollo grouting at H2 input, HAM7, MC legs.
- PSL working on controls, DAQ.
- Platt Electric makes delivery for Richard.
- One Apollo delivery in the afternoon.
- Transit of Venus broadcast in Control Room. Some visitors on site expected for LHO's special event. Unfortunately, the sky was overcast for the entire day, so the sun was not visible at LHO as of 18:00. Check back here on 8 Dec 2125, LHO's next chance.
- OSB doors locked at 16:45.

I noticed condensed water vapor collecting at the exhaust of the QDP80 -> My measuring of the purge air dew-point prior to pumping yesterday was of the air exhausting into the room from the check valve (acting as a point-of-use pressure relief).  This had been the nominal procedure until recent years after we had observed that the purge air drying towers could be "starved" in a maximum demand case, such as full-open purge air valves in conjunction with one or more chamber doors being removed.  We found then that the measured dew-point of air sourced only from the VE (during pressure equalization "blow-down" prior to pump-down) could be different than that of the air sourced only from the purge air header.  This could result from those scenarios where the drying towers were starved at the time that the door(s) were reinstalled.  Once the doors are installed, there is minimal air exchange between the relative "wet" air in the VE and the relatively "dry" air that the, now not-starved drying towers, were supplying to the header.  

This has not been observed at the Corner Station as we haven't been able to "starve" the drying towers with nominal purge air demands.  

We intended to make it standard practice to measure the dew-point of the air exhausting into the room during the "blow-down" step when preparing to pump down a -mid or -end volume.  

See if I can post a plot......

Attached are plots of dust counts > .5 microns.

Hugh, Hugo,

LLO observed grounding issues with actuators on HAM-ISIs (see LLO aLog #2890) . Actuator cables have their shielding covered by a fairly large mesh. If the cable is pinched against a wall, or set in tight contact with a CPS sheild (which is grounded to the ISI), the actuator gets grounded to the ISI.

We checked the grounding status of all actuators of HAM-ISI Unit #4 (HAM2 Chamber) by testing the continuity between the shielding pin of the actuator cable and the ISI. Even though most actuator cables are tied with CPS shields (picture 1), no actuator were grounded to the ISI on this unit.

We also noticed remains of aluminium bands at the connection between the actuator and its cable, that we removed. To do so, we had to open the door of Act-H1 (picture 2). This door still has to be torqued down with a torque wrench. It will be taken care of tomorrow.

I restarted H1 DAQ, now h1fw0 and h1fw1 are writing identical frames.

h2susb78 (FMY) remains unstable. We have been making incremental changes to pin down the problem:

Reattached to Dolphin network

only run the IOP model

reseat all ADC/DAC cards

rearrange ADC/DAC cards to LHO CDS standard (ref Rolf's IO Chassis document)

We have been stable for 2.5 hours with the latest configuration: Dolphin attached, IOP model only, LHO-CDS card layout. Will run with this overnight.

Kyle
Purge air dewpoint measured <-35C now that doors and dome have been on for a few days and the flow demand is low enough for the drying towers to be effective (found pressure relief valve for scroll compressor #2 is stuck open and won't re-seat -> valved-out output of compressor #2 and de-energized it).  

Began pumping Y-end this morning.  

Kyle
~1600 hrs local 
Y-end pressure at 2.8 torr, going home now -> Closed O-ring valve at Turbo header, closed 10" gate valve at MTP inlet, switched safety valve switch to "Closed" position to close the safety valve, cracked open valve between Purge Air header and Turbo header to let the QDP80 pump a slight viscous load overnight. 

Will restore roughing configuration in the morning then switch over to MTP when pressure low enough.

Powered down HEPI valve drive chassis and ±24V power going to HEPI Interface modules. Replaced R13 from a 2 KOhm resistor to a 33.2K Ohm resistor on D080521 units. This changes the gain of the L4C channels from 22 to 333, per document E1200420-v1. Tested units after mods, gain ~330. Serial Numbers of units modified: S0900178, S0900236, S0900202, and S0900234. Will reinstall units tomorrow morning.

(corey, eric, greg, hugo, jim, mitch)

#6

Now that we had some hardware processsed, we were able to continue building up Actuators.

#7

Stiffener Assembly completed.  The Support Posts were installed (discovered we were missing a Gang Barrel Nut [it was in our "dirty" bin]); will want to get it processed before we pull down springs.

Stage0 Assembly moved to Test Stand.

Stage1 plate put on Assembly Stand.

The set of 6 horizontal L4Cs received in shipment load #3880 were huddle tested this morning, 

We noted a few points that we need to be careful about in order to perform this test correctly:

• Level the instruments
• Have them properly seated (check that they do not rock)
• Direct the instruments towards the same direction

Spectra are attached.