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Reports until 13:51, Wednesday 06 August 2025
LHO VE (DetChar, VE)
travis.sadecki@LIGO.ORG - posted 13:51, Wednesday 06 August 2025 - last comment - 08:30, Thursday 28 August 2025(86227)
BTRP adapter flange and GV installed at MX

Yesterday, we installed the BTRP (Beam Tube Roughing Pump) adapter flange on the 13.25" gate valve just to the -X side of GV13.  This included installing a 8" GV onto the roughing pump port of the adapter, moving the existing gauge tree onto the new adapter, and installing a 2.75" blank on an unused port.  All of the new CF joints were helium leak tested and no signal was seen above the ~9e-11 torrL/s background of the leak detector. 

The assembly is currently valved out of the BT vacuum volume via the 13.25" GV, and is being pumped down via small turbo and aux cart.  Therefore, the PT-343 gauge reading is only reporting on the BTRP assembly pressure, not the main BT pressure, so it can be ignored until further notice of it being vavled back in.  This system has been pumping via aux cart or leak detector since ~2pm yesterday, and will continue to be pumped until it is in the pressure range of the BT volume.  The aux cart is isolated by foam under the wheels, but some noise may be noticed by DetChar folks, hence the DetChar tag on this report.

Comments related to this report
janos.csizmazia@LIGO.ORG - 16:08, Wednesday 06 August 2025 (86230)
A before - after pair of photos.
As the conductance is very bad in this complex volume, we're aiming to pump it until next Tuesday. The estimated pressure rise of the main volume after valving in this small volume next Tuesday is less than E-12 Torr (after equalizing) - in other words, negligible.
Images attached to this comment
anna.iudintseva@LIGO.ORG - 16:20, Wednesday 06 August 2025 (86231)
Some backstage snapshots of the great teamwork of Travis, Janos, and me on installing these: Pic. 1 - "before"; 2,3 - 90% complete.
Images attached to this comment
travis.sadecki@LIGO.ORG - 09:39, Wednesday 13 August 2025 (86338)

As of Tuesday, August 12, the pumps have been shut off and removed from this system, and the gauge tree valved back in to the main volume.  Noise/vibration and pressure monitoring at MX should be back to nominal.

janos.csizmazia@LIGO.ORG - 08:30, Thursday 28 August 2025 (86607)
LOTO was applied now both to the handlers of the hand angle valve and the hand Gate Valve.
Also, components have been added to the header, only 1 piece away from the booster pump.
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