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<p>Ben,</p>
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<p> Maybe someone else on the list can shed some light on this, but I don't know whether the strength of the plasma created in an EM "glow discharge device" is comparable to that of what is called a "plasma cleaner." I suspect not, but could be wrong.<br>
</p>
<p><br>
</p>
<p> That said, over zealous use of a plasma cleaner can remove _all_ the carbon from an EM grid (I have done this with a lacy carbon grid), so having too much power can be a bad thing...<br>
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David Gene Morgan<br>
Electron Microscopy Center<br>
047D Simon Hall<br>
IU Bloomington<br>
812 856 1457 (office)<br>
812 856 3221 (3200)<br>
http://iubemcenter.indiana.edu</div>
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>From:</b> benoit.zuber@ana.unibe.ch <benoit.zuber@ana.unibe.ch><br>
<b>Sent:</b> Tuesday, September 20, 2016 12:06 PM<br>
<b>To:</b> Morgan, David Gene; 3dem@ncmir.ucsd.edu<br>
<b>Subject:</b> Re: glow discharge vs plasma cleaning</font>
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<p class="MsoNormal"><span style="">Hi David and Luiza,</span></p>
<p class="MsoNormal"><span style=""> </span></p>
<p class="MsoNormal"><span style="">Many thanks for the explanations. OK this « makes sense ». But it is a shame that people use two different words for the same thing (good job from the marketing team though ! ). It would be much better to use only one term
and then give specific gaz conditions. So many people are convinced that glow discharge and plasma cleaning are two different things and that you need two different machines.</span></p>
<p class="MsoNormal"><span style="">We have a so-called glow discharge machine from defunct Balzers. It still functions perfectly well, it looks like what people describe as a glow discharge machine : a glass cylinder with two metal plates below and on top,
and it has an needle-valve inlet. We typically let the inlet in contact with the air and let a tiny bit of air flow in to get a constant pressure in the chamber and thereby have a reproducible procedure. We can quite precisely control the pressure that we
want inside. However if we want to use whatever gas mixture instead of good old nitrogen and oxygen, we can just buy and connect the relevant gas bottle(s). No need to purchase a new machine.
</span></p>
<p class="MsoNormal"><span style="">If I listened to what so many people told me, I would have long bought another machine, which would probably have been a waste of money and lab space. I think people should be more aware of this before spending their (tax
payer ?) money.</span></p>
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<p class="MsoNormal"><span style="">Cheers</span></p>
<p class="MsoNormal"><span style="">Benoît</span></p>
<p class="MsoNormal"><span style=""> </span></p>
<p class="MsoNormal"><span style=""> </span></p>
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<p class="MsoNormal"><b><span style="color:black">De : </span></b><span style="color:black">"Morgan, David Gene" <dagmorga@indiana.edu><br>
<b>Date : </b>mardi, 20 septembre 2016 17:51<br>
<b>À : </b>Benoit Zuber <benoit.zuber@ana.unibe.ch><br>
<b>Objet : </b>Re: glow discharge vs plasma cleaning</span><span style="font-size:12.0pt; color:black"></span></p>
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<p style="background:white"><span style="font-family:Calibri; color:black">Ben,</span></p>
<p style="background:white"><span style="font-family:Calibri; color:black"> </span></p>
<p style="background:white"><span style="font-family:Calibri; color:black"> They are technically the same thing _except_ that in common EM usage, "glow discharge" is done using ambient gases (i.e., you just pull a modest vacuum and create a plasma) while "plasma
cleaning" is done using a specific mix of gases (Ar, O and with the Gatan device H) instead of ambient gases (i.e., you flush the chamber with specific gases, then pull the vacuum and create the plasma).</span></p>
<p style="background:white"><span style="font-family:Calibri; color:black"> </span></p>
<p style="background:white"><span style="font-family:Calibri; color:black"> With more O in the plasma, the cleaning tends to be stronger (burns more material in the sample) and the Ar/O mix prevents side reactions that can be caused by the abundant N in the
atmosphere. </span></p>
<p style="background:white"><span style="font-family:Calibri; color:black"> </span></p>
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<p class="MsoNormal" style="background:white"><span style="font-size:12.0pt; color:black"> David Gene Morgan<br>
Electron Microscopy Center<br>
047D Simon Hall<br>
IU Bloomington<br>
812 856 1457 (office)<br>
812 856 3221 (3200)<br>
http://iubemcenter.indiana.edu</span></p>
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<p class="MsoNormal" style="background:white"><b><span style="color:black">From:</span></b><span style="color:black"> 3dem <3dem-bounces@ncmir.ucsd.edu> on behalf of benoit.zuber@ana.unibe.ch <benoit.zuber@ana.unibe.ch><br>
<b>Sent:</b> Tuesday, September 20, 2016 11:28 AM<br>
<b>To:</b> 3dem@ncmir.ucsd.edu<br>
<b>Subject:</b> [3dem] glow discharge vs plasma cleaning</span><span style="font-size:12.0pt; color:#212121">
</span></p>
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<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN-US">Dear colleagues,</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN-US"> </span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN-US">I often hear people saying: „Did you treat your grid with glow discharge or with plasma cleaner?” Or : ”It is absolutely essential for application XY to pretreat the grid
with a plasma cleaner and not by glow discharge!”.</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN-US"> </span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN-US">Can anyone explain what the difference between glow discharge and a plasma cleaning is?</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN-US"> </span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN-US">According to Wikipedia, this is the same thing (<a href="https://en.wikipedia.org/wiki/Glow_discharge">https://en.wikipedia.org/wiki/Glow_discharge</a>). The page starts
with this sentence:</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN-US">“</span><span style="color:#212121" lang="EN">A
<b>glow discharge</b> is a <a href="https://en.wikipedia.org/wiki/Plasma_(physics)" title="Plasma (physics)">
plasma</a> formed by the passage of <a href="https://en.wikipedia.org/wiki/Electric_current" title="Electric current">
electric current</a> through a low-pressure gas”</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN"> </span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN-US">I look forward to an interesting debate.</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN-US">Ben</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN-US"> </span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN-US">Prof. Benoît Zuber</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="EN-US">Institute of Anatomy</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="DE-CH">University of Bern</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="DE-CH">Baltzerstrasse 2</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="DE-CH">Postfach 922</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="DE-CH">3000 Bern 9</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="DE-CH">Switzerland</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="DE-CH">Tel. +41 31 631 84 40</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="DE-CH">benoit.zuber@ana.unibe.ch</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121" lang="DE-CH">http://www.ana.unibe.ch/~exmo/</span><span style="color:#212121"></span></p>
<p class="MsoNormal" style="background:white"><span style="color:#212121"> </span></p>
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