[3dem] Arching in the gun chamber

[Bowman, Valorie D]

Dear Hiro,

It means the vacuum is not good in the FEG.  You may have a leak.  Check the IGP value in the FEG and ask your service engineer what values are safe to use on your microscope.

It will destroy your filament!  If you keep using it this way one of the arcs will "blow" (short out) the filament and you will have to have it replaced.

And yes, it will affect data quality.  It means your FEG will not be giving you the coherent beam you want.

Hope this helps,

Valorie

Valorie Bowman

vdb at purdue.edu

Senior Research Electron Microscopist
Purdue Cryo EM Facility
Purdue University
________________________________
From: 3dem [3dem-bounces at ncmir.ucsd.edu] on behalf of kunihiro uryu [kuryu at mail.rockefeller.edu]
Sent: Friday, July 17, 2015 8:48 AM
To: 3DEM Mailing List
Subject: [3dem] Arching in the gun chamber


We have experiencing arching in the gun chamber. Has anyone experienced it? If so, did it affect data quality? How did you fix it?  Many thanks in advance.

Regards,
Hiro

------
Kunihiro Uryu, Ph.D.,
Research Assistant Professor
Director of Electron Microscopy
Resource Center (EMRC)
RRB Rm120
The Rockefeller University
1230 York Ave., Box 230
New York, NY 10065
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