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Entry  Wed Sep 7 12:03:49 2011, steve, Update, VAC, Pump down has started 
    Reply  Wed Sep 7 18:19:37 2011, steve, HowTo, VAC, stop pump down for overnight 
       Reply  Wed Sep 7 21:45:16 2011, kiwamu, Update, VAC, pump stopped. Pressure is at 450 mtorr vacuum.png
       Reply  Thu Sep 8 10:50:44 2011, steve, Update, VAC, pumpdown #71 comleted pd#71.jpgmaglevpd.jpg
Message ID: 5365     Entry time: Thu Sep 8 10:50:44 2011     In reply to: 5361
Author: steve 
Type: Update 
Category: VAC 
Subject: pumpdown #71 comleted 

Vacuum status:  " vacuum normal"   CC1 pressure 5e-5 Torr

Slow roughing through butterfly valve took 11 hours at 1-2 Torr/min speed.  We had a leak at the metal hose connecting o-ring  that became visible  at 200 Torr.

The vacuum envelope pressure rose to 500 mTorr from 450 mTorr  This is 50 mTorr leak plus outgassing over 11 hrs  over night stop =  5  mTorr /  hr

Atm2, Maglev pumpdown details. P2 and P3  are in the foreline of the Maglev. The pressure peaks at 4 Torr beacause the 3 drypumps have  little pumpimg speed at this range.

            External fan is turned on during this one hour period to prevent  Maglev turbo from overheating.

            Same things are  happenning with the two small TP2 and TP3 pumps under load. Their foreline pressure peak at 1 Torr.  They slow down to 45 K RPM from 50K RPM  and warm up to 36-39 C

Precondition: 36 days at atm

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