Subject: [Fwd: Problem raith SNF 2005-07-18 13:15:36: EHT trip overnight SUNDAY brought gun down hard]
From: James Conway <jwc@snf.stanford.edu>
Date: Tue, 19 Jul 2005 11:20:32 -0700



Greetings:

Users are requested to soft bake at 90 degrees Celsius for 1:30 - 2:00 min all samples going into the system.

This arc event appeared to be related to an outgasing event during the write abut an hour after staring the exposure.
The EHT Extractor Current trip recorded a gun pressure in the 5.6E-009 mbar at the time of the arcing event.  There is a set point that the gun will turn itself off at 6.0E-009 mbar.  Normal gun pressure during most exposures is normally 1.2E-009 mbar and it rarely shows any rise above that level.

Should this reoccur I will need to take the system off line for some time period while I perform an extended bake out of the gun section. (48 - 100 hours) This approach would be to bake out the system, drive contamination out of the gun section, and reduce the gun section pressure down into the target 5.0 - 8.0 E -010 mbar range.

The gun was brought up yesterday afternoon and FE-GUN emission is significantly lower than before the EHT trip event, and it may take several days to return to normal levels.  Further testing are in progress.

Thank you,

James Conway


-------- Original Message --------
Subject: Problem raith SNF 2005-07-18 13:15:36: EHT trip overnight brought gun down hard
Date: Mon, 18 Jul 2005 13:15:36 -0700
From: jwc@snf.stanford.edu
To: raith-pcs@snf.stanford.edu


03:04 Sunday morning a EHT TRIP occured and brought the gun down on Users EDO exposure.
System off line for afternoon while we bring gun up and certify operations.  Users with critical work should reschedule for later sessions.  Should be up and stable by 9 PM.
James Conway 07182005:13:14:00