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<div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 10pt;">Dear Hiro,<br>
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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.<br>
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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.<br>
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And yes, it will affect data quality. It means your FEG will not be giving you the coherent beam you want.<br>
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Hope this helps,<br>
<br>
Valorie<br>
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<div style="font-family:Tahoma; font-size:13px">Valorie Bowman<br>
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vdb@purdue.edu<br>
<br>
Senior Research Electron Microscopist<br>
Purdue Cryo EM Facility<br>
Purdue University</div>
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<div style="direction: ltr;" id="divRpF638011"><font face="Tahoma" size="2" color="#000000"><b>From:</b> 3dem [3dem-bounces@ncmir.ucsd.edu] on behalf of kunihiro uryu [kuryu@mail.rockefeller.edu]<br>
<b>Sent:</b> Friday, July 17, 2015 8:48 AM<br>
<b>To:</b> 3DEM Mailing List<br>
<b>Subject:</b> [3dem] Arching in the gun chamber<br>
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<p style="margin:0in 0in 10pt"><font face="Calibri"><font size="3"><font color="#000000">We have experiencing arching in the gun chamber.<span> </span>Has anyone experienced it? If so, did it affect data quality? How did you fix it? <span> Many thanks in advance.</span></font></font></font><br clear="all">
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<div>Regards,</div>
<div>Hiro</div>
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<div>------</div>
<div>Kunihiro Uryu, Ph.D., </div>
<div>Research Assistant Professor<br>
Director of Electron Microscopy <br>
Resource Center (EMRC)<br>
RRB Rm120<br>
The Rockefeller University<br>
1230 York Ave., Box 230<br>
New York, NY 10065</div>
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