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<div>We had a T12 with this issue and lots of contamination in the chamber. There was this little plug looking piece that has a special tool to remove it that sits under the chamber, in the column. That was very dirty and we replaced it with a new one and all
is well. </div>
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<div>Cheers,</div>
<div>Cindi</div>
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<div>_______________________________________</div>
<div>Cindi L. Schwartz</div>
<div>Electron Microscopist</div>
<div>Rocky Mountain Laboratories/NIAID/NIH</div>
<div>903 South 4th Street</div>
<div>Hamilton, MT 59840</div>
<div>(240)669-5473</div>
<div><a href="mailto:Cindi.Schwartz@NIH.Gov">Cindi.Schwartz@NIH.Gov</a></div>
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<span style="font-weight:bold">From: </span>kunihiro uryu <<a href="mailto:kuryu@mail.rockefeller.edu">kuryu@mail.rockefeller.edu</a>><br>
<span style="font-weight:bold">Date: </span>Friday, July 17, 2015 at 8:59 AM<br>
<span style="font-weight:bold">To: </span>"Bowman, Valorie D" <<a href="mailto:vdb@purdue.edu">vdb@purdue.edu</a>><br>
<span style="font-weight:bold">Cc: </span>3DEM Mailing List <<a href="mailto:3dem@ncmir.ucsd.edu">3dem@ncmir.ucsd.edu</a>><br>
<span style="font-weight:bold">Subject: </span>Re: [3dem] Arching in the gun chamber<br>
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<div>Hi Valorie,</div>
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<div>Thanks for your swift reply. We do experience shortage of tip life (of Lab6). Our service engineers made sure high vacuum level and exchanged many parts, including insulating oil, IGP and the gun cable. They even tried a new HT generator. The chamber is
practically new by now. It is still a tough arching to get rid of. Recent serious cleaning of chamber made a significant difference. It is now less frequent, but we still experience time to time.</div>
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<div>I think that something, possibly vacuum leak and/or overtime accumulation of contamination in the chamber, must have led the chamber susceptible to arching. Repeated arching caused more contamination and exacerbated the whole situation. How can we get
rid of arching completely? Any suggestions would be appreciated.<br>
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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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<div class="gmail_quote">On Fri, Jul 17, 2015 at 9:25 AM, Bowman, Valorie D <span dir="ltr">
<<a href="mailto:vdb@purdue.edu" target="_blank">vdb@purdue.edu</a>></span> wrote:<br>
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<div style="color:rgb(0,0,0);font-family:Tahoma;font-size:10pt;direction:ltr">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>
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Valorie<br>
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<div style="font-family:Tahoma;font-size:13px">Valorie Bowman<br>
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<a href="mailto:vdb@purdue.edu" target="_blank">vdb@purdue.edu</a><br>
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Senior Research Electron Microscopist<br>
Purdue Cryo EM Facility<br>
Purdue University</div>
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<div style="direction:ltr"><font color="#000000" face="Tahoma" size="2"><b>From:</b> 3dem [<a href="mailto:3dem-bounces@ncmir.ucsd.edu" target="_blank">3dem-bounces@ncmir.ucsd.edu</a>] on behalf of kunihiro uryu [<a href="mailto:kuryu@mail.rockefeller.edu" target="_blank">kuryu@mail.rockefeller.edu</a>]<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 are 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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