janos.csizmazia@LIGO.ORG - posted 16:35, Thursday 01 February 2024 - last comment - 19:46, Thursday 01 February 2024(75682)
2-1 vent vacuum diary
Today's activities: - EX pumpdown continues. The pressure is in the mid-E-7s already, after ~37 hours of pumping. - EX was also leak checked: the newly installed 12" blank on BSC5; the new RGA angle valve; and the dismounted and re-mounted 3 viewports were leak-checked, and all passed nicely: see it more in-detail in the comments - At EX the last thing to do is the RGA bakeout, which will be started on next Monday - From BSC8 all the 12" 3IFO feedthroughs were removed, and they were replaced with blanks (5 pcs. of them). The removal of the particularly awkwardly placed 16.5" feedthroughs has been started (there are 3 of them). - The purge air dew point was measured in the LVEA, and found satisfactory (~-42 deg C) - see more in-detail in the comments
Helium leak detector was connected to the foreline of the main turbopump at EX, and five new flanges (listed above) were sprayed with helium. No helium signature observed above the leak detector background of ~4E-10 Torr-l/s. Foreline was switched back to the local scroll pump to continue pumpdown.
Today's dew point measurement in the LVEA attached, -42.2degC at the output tube prior to in-chamber activities