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Entry  Fri Apr 24 16:02:31 2009, steve, HowTo, VAC, cryo pump interlock rule cryo.png
    Reply  Wed Apr 29 10:20:14 2009, steve, HowTo, VAC, cryo pump interlock rule is waved 
Message ID: 1532     Entry time: Wed Apr 29 10:20:14 2009     In reply to: 1517
Author: steve 
Type: HowTo 
Category: VAC 
Subject: cryo pump interlock rule is waved 


I tested the cryopump interlock today. It is touchy. I do not have full confidence in it.

I'm proposing that VC1 gate valve should be kept closed while nobody is working in the 40m lab.

How to open gate valve:

1, confirm temp of 12K on the gauge at the  bottom of the cryopump

2, if medm screen cryo reads OFF( meaning warm) hit reset will result reading ON (meaning cold 12K )

3, open VC1 gate valve if P1 is not higher than 20 mTorr


VC1 was closed at 18:25,

IFO condition: not pumped,

expected leak plus  out gassing should be less than 5 mTorr/day

The RGA is in bg-mode, annuloses are closed off

 The Cryo pump is running reliably since April 22 hence there is no need to close VC1 repeatedly.

The photo switch interlock was put back onto the H2 vapor pressure gauge and it is working.

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