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Entry  Mon Dec 6 14:26:52 2021, Koji, Update, VAC, Pumping down the RGA section 
    Reply  Tue Dec 7 13:12:50 2021, Koji, Update, VAC, Pumping down the RGA section 
       Reply  Wed Dec 8 10:14:43 2021, Jordan, Update, VAC, Pumping down the RGA section 40m_RGAVolume_12_8_21.PNG40m_RGAVolume_Torr_12_8_21.PNG
          Reply  Fri Dec 10 19:22:01 2021, Koji, Update, VAC, Pumping down the RGA section 
Message ID: 16494     Entry time: Wed Dec 8 10:14:43 2021     In reply to: 16493     Reply to this: 16501
Author: Jordan 
Type: Update 
Category: VAC 
Subject: Pumping down the RGA section 

After an overnight pumpdown/RGA warm up, I took a 100 amu scan of the RGA volume and subsequent pumping line. Attached is a screenshot along with the .txt file. Given the high argon peak (40) and the N2/O2 ratio, it looks like there is a decent sized air leak somehwere in the volume.

Are we interested in the hydrocarbon leak rates of this volume? That will require another scan with one of the calibrated leaks opened.

Edit: Added a Torr v AMU plot to see the partial pressures

Quote:

So that Jordan can run the RGA scan this afternoon, I ran TP3 and started pumping down the RGA section.

Procedure:
- Same 1~4
- Same 5
- 6 Opened only the backing path for TP3
- 7 Turned on TP3 only

- TP3 reached the nominal full speed @75kRPM

- 11 Opened V5 to pump the pump spool -> Immediately reached P3<1e-4
- 12 Opened VM3 to pump the RGA section -> Immediately reached P4<1e-4

The pumps are kept running. I'll come back later to shut down the pumps.
=> Jordan wants to heat the filament (?) and to run the scan tomorrow.
So we decided to keep TP3 running overnight. I switched TP3 to the stand-by mode (= lower rotation speed @50kRPM)

 

 

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Attachment 2: 40m_RGAVolume_Torr_12_8_21.PNG  84 kB  Uploaded Fri Dec 10 13:36:33 2021  | Hide | Hide all
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