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Entry  Wed Jan 9 20:01:25 2019, Jon, Update, VAC, Second pumpdown completed Screenshot_from_2019-01-09_20-00-39.pngIMG_3088.jpg
    Reply  Thu Jan 10 10:23:46 2019, gautam, Update, VAC, overnight leak rate OvernightLeak.png
       Reply  Sat Feb 2 21:53:24 2019, Koji, Update, VAC, overnight leak rate Screen_Shot_2019-02-02_at_21.49.33.png
          Reply  Sun Feb 3 15:15:21 2019, gautam, Update, VAC, overnight leak rate Jan10_data.pngFeb1_data.png
             Reply  Sun Feb 3 20:52:34 2019, Koji, Update, VAC, overnight leak rate 
                Reply  Mon Feb 4 12:23:24 2019, gautam, Update, VAC, pumpdown 83 - leak tests PD83.png
                   Reply  Tue Feb 5 10:11:30 2019, gautam, Update, VAC, leak tests complete, pumpdown 83 resumed Annuli.pngMainVol.png
                      Reply  Tue Feb 5 19:30:14 2019, gautam, Update, VAC, Main volume at 20 uTorr PD83.png
                         Reply  Thu Feb 7 13:55:25 2019, gautam, Update, VAC, RGA turned on 
                            Reply  Thu Feb 7 19:28:46 2019, gautam, Update, VAC, IFO recovery 
Message ID: 14393     Entry time: Wed Jan 9 20:01:25 2019     Reply to this: 14394
Author: Jon 
Type: Update 
Category: VAC 
Subject: Second pumpdown completed 

[Jon, Koji, Chub, Gautam]

Summary

The second pumpdown with the new vacuum system was completed successfully today. A time history is attached below.

We started with the main volume still at 12 torr from the Dec. pumpdown. Roughing from 12 to 0.5 torr took approximately two hours, at which point we valved out RP1 and RP3 and valved in TP1 backed by TP2 and TP3. We additionally used the AUX dry pump connected to the backing lines of TP2 and TP3, which we found to boost the overall pump rate by a factor of ~3. The manual hand-crank valve directly in front of TP1 was used to throttle the pump rate, to avoid tripping software interlocks. If the crank valve is opened too quickly, the pressure differential between the main volume (TP1 intake) and TP1 exhaust becomes >1 torr, tripping the V1 valve-close interlock. Once the main volume pressure reached 1e-2 torr, the crank valve could be opened fully.

We allowed the pumpdown to continue until reaching 9e-4 torr in the main volume. At this point we valved off the main volume, valved off TP2 and TP3, and then shut down all turbo pumps/dry pumps. We will continue pumping tomorrow under the supervision of an operator. If the system continues to perform problem-free, we will likely leave the turbos pumping on the main volume and annuli after tomorrow.

New Vac Control Station

We installed a local controls terminal for the vacuum system on the desk in front of the vacuum rack (pictured below). This console is connected directly to c1vac and can be used to monitor/control the system even during a network outage or power failure. The entire pumpdown was run from this station today.

To open a controls MEDM screen, open a terminal and execute the alias

$control

Similarly, to open a monitor-only MEDM screen, execute the alias

$monitor
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