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Entry  Wed May 22 22:50:13 2019, gautam, Update, VAC, Pumpdown prep 
    Reply  Thu May 23 15:30:56 2019, gautam, Update, VAC, Pumpdown underway - so far so good! pumpdownPres.png
       Reply  Fri May 24 11:47:15 2019, gautam, Update, VAC, IFO is almost at nominal vacuum pumpdown_20190524.png
          Reply  Mon May 27 11:37:13 2019, gautam, Update, VAC, c1vac is unresponsive 
             Reply  Tue May 28 09:51:33 2019, gautam, Update, VAC, c1vac hard-rebooted Screen_Shot_2019-05-31_at_12.44.54_PM.png
Message ID: 14634     Entry time: Thu May 23 15:30:56 2019     In reply to: 14631     Reply to this: 14636
Author: gautam 
Type: Update 
Category: VAC 
Subject: Pumpdown underway - so far so good! 

[chub, koji, gautam]

  1. We executed the pre-pumpdown tasks per the checklist - heavy doors were on by ~1030am.
  2. We were thwarted by the display of c1vac becoming unresponsive - the mouse cursor moves, but we could not interact with any screens. Connecting to c1vac by ssh with the -X option, we could interact with everything. Using top, we saw that the load average was reporting ~8 - this is pretty high! The most demanding processes were the modbus IOC and some python processes, presumably connected with the interlocks. We tried stopping the interlock systemctl process, kill -9ing the heavy processes, but to no avail. Next, we tried killing the X display proces, but this also did not fix the problem. Finally, we did a soft reboot of c1vac - the machine came back up, but still no interactivity. So we moved asia, the EY laptop, to the vacuum station for this pumpdown. We will fix the situation once the vacuum is in the nominal state.
  3. The actual pumpdown commenced by first evacuating the EY and IY annular volumes with the roughing pump. There is an interlock condition that prevents V6 from being opened if the PRP gauge reports < 0.25 torr (this is to protect against oil backstreaming from the roughing pumps I believe). To get around this, we gave the roughing pumps some work by exposing the annular line to the atmospheric pressure of the EY and IY annuli. In a few minutes, both of these reported < 1 torr.
  4. Main volume pumping started around noon - we have been going down in pressure steadily at ~3 torr/min (Koji has a nice python utility made that calculates the rate from the pressure channel).
  5. At the time of writing, after ~3.5 hrs of pumping, we are at 25 torr. I will keep going till ~1 torr, and then valve off the main volume until tomorrow, when Chub and I will work on getting the turbo pumps exposed to the main volume. Pausing at 355pm while I go for the colloquium. Resumed later in the evening, stopping for today at 500 mtorr.
  6. In preparation for the increased load on TP2 and TP3, I spun them up to the "high RPM mode" from their nominal "Standby mode".

Close up photos of the EY and IY chambers may be found here.

Update on the display manager of c1vac: I was able to get it working again by running sudo systemctl restart display-manager. Now I can interact with the MEDM screens on c1vac. It is a bit annoying that this machine doesn't have the users directory so I don't have access to the many convenient StripTool templates though - maybe I'll make local copies tomorrow for the pumpdown.

Attachment 1: pumpdownPres.png  53 kB  Uploaded Thu May 23 16:47:55 2019  | Hide | Hide all
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