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Reports until 16:04, Thursday 13 August 2020
H1 CDS (VE)
david.barker@LIGO.ORG - posted 16:04, Thursday 13 August 2020 - last comment - 10:31, Friday 14 August 2020(56474)
Vacuum beam tube alarm levels increased following closure of gate valves GV1 and GV2

Chandra, Dave:

Following the closure of GV1 and GV2 earlier this afternoon, the beam tube pressures have been slowly increasing and recently LY exceeded its 5.0e-09 Torr level. Chandra has authorized me to increase the alarm level to 1.0e-08 Torr on both X and Y arm gauges, which I have done and restarted the alarm system.

Attached 3 hour trend shows y-arm gauge exceeding 5.0e-09 Torr.

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Comments related to this report
david.barker@LIGO.ORG - 10:31, Friday 14 August 2020 (56487)
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Looks like Y-Arm beam tube vacuum has settled at 7.6e-09 Torr, so the current alarm level of 1.0e-08 Torr looks suitable for the weekend.

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david.barker@LIGO.ORG - 19:17, Thursday 13 August 2020 (56483)
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I did the same on CP1's vacuum gauge,  H0:VAC-LY_Y3_PT114B_PRESS_TORR

chandra.romel@LIGO.ORG - 23:10, Thursday 13 August 2020 (56485)VE
Link

There is a known -8 range leak on the CF flange above bonnet of GV6 (aLOG 42775) so this is why the pressure always rises beyond alarm thresholds on y-arm when we valve out the ion pumps.

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