Reports until 18:41, Thursday 17 September 2026
LHO VE (VE)
gerardo.moreno@LIGO.ORG - posted 18:41, Thursday 17 September 2026 - last comment - 16:49, Friday 18 September 2026(91969)
YBM and XBM Vent Recovery

(Travis S., Jordan V., Richard M., Gerardo M.)
After the installation of CHeTA viewports, we connected an ISP-1000 scroll pump and a SS-500 cart to each of the main turbo pumps at the X beam manifold and Y beam manifold.  After getting power sorted out to the ISP-1000s, thanks Richard, we started the pumpdown for both of the manifolds.
Something that we did noted was the new gauge for PT-180 shows almost 1000 Torr for pressure at atmosphere, this is not correct, then the other gauge for PT-170 shows 750 Torr for pressure at atmosphere, also not right.
Pumpdown has been stopped at the end of the day, and will be restarted tomorrow morning by Jordan.

Attached is a plot of both manifolds initial pumpdown.

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jordan.vanosky@LIGO.ORG - 16:49, Friday 18 September 2026 (91979)

Continued pumpdown of the XBM and YBM this morning, using 1x ISP1000 and 1x ISP500 for each volume.

Starting Pressure: 45 torr Start Time: 8:25 am
Turbo Crossover Pressure: 500 mtorr

Turbo On: 3:10 pm (XBM)

                   3:25 pm (YBM)

Total roughing time was ~ 10 hours, 3 hours and 15 minutes yesterday + 6 hours and 45 minutes today.

Once the turbopump reached full speed and chamber pressure was ~5E-5 Torr, I transitioned from the roughing pumps to the dedicated ISP250 and 80 l/s turbopump for the foreline.

Cooling water was adjusted so that pump and controller temps were ~40C. Setpoints adjusted to 1E-5 Torr.

We will need to leak test the 3 newly installed viewports before opening gate valves.

Images attached to this comment