<div dir="ltr"><div>Have you tried rebuilding the gun assembly? Sometimes the ceramic pieces get too much metal on them and cause a short.</div><div>Replace all the ceramics and make sure your filament has good clearance. Some filaments can only go in one way because of the coil direction.</div><div><br></div><div>Jim</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Jul 8, 2021 at 3:57 PM Nathanael Sieb <<a href="mailto:sieb@4dlabs.ca">sieb@4dlabs.ca</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<p>Hi all,</p>
<p>We are trying to trouble-shoot a PVD e-beam source and can't seem
to figure out the problem. Early in the year we sent the assembly
out for repair and refurbishment. (we burned a hole in the
internal bellows tubing, long story) When we got it back we
connected it back to the system and started it up. However, we
haven't been able to get a stable emission current. The HV stays
on but the filament current, and hence emission current,
occasionally cuts out. It comes back a second later, over-shoots
the target current, and then restabilizes. It happens at low
emission currents and some higher ones. The timing is random.
Sometimes it happens frequently, sometimes you can run 15 min
without a problem. There are no errors from the power supply.<br>
</p>
<p>We took a video of the issue and it happens at around the 1min
mark <a href="https://www.dropbox.com/s/7n42e38qviju7ga/Both_emission_and_filament_spiking_and_turning_off.mov?dl=0" target="_blank">here</a>.
The advice from vendors was to look for a loose connection. We
have checked all the external connections and tried to look at the
internal ones too. Last week we removed the filament and
reinstalled it. We didn't see any problems and we still have the
same issue.</p>
<p>We're running out of ideas other than sending it back to the
vendor to examine the entire assembly again. Has anyone else
encountered this type of problem? Any suggestions?</p>
<p>Thanks,<br>
Nathanael<br>
</p>
<div>
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<p style="font-family:Arial,Helvetica,sans-serif;font-size:13.3333px"> <b style="font-family:Calibri,Helvetica,sans-serif;font-size:16px"> <span style="font-family:Arial,Helvetica,sans-serif;font-size:10pt">Nathanael Sieb</span> </b> <br style="font-family:Calibri,Helvetica,sans-serif;font-size:16px">
<span style="font-family:Arial,Helvetica,sans-serif;font-size:10pt"><span style="font-size:10pt">Director of
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<span style="font-family:Arial,Helvetica,sans-serif;font-size:10pt">8888 University Dr., Burnaby, B.C. V5A 1S6</span>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><span style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000"><i><b>James Mitchell</b></i></font></span><div style="font-size:12.8px"><font color="#990000"><span style="font-size:12px;background-color:rgb(248,248,248)"><i><font face="verdana, sans-serif"><b>Specialty Trades Technician</b></font></i></span></font></div><div style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000"><i>Dept. of Electrical and Computer Engineering</i></font></div><div style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000" style="letter-spacing:0.2px"><i>NCSU Nanofabrication Facility</i></font></div><div style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000" style="letter-spacing:0.2px"><i>MRC RM243A </i></font><font color="#990000" face="verdana, sans-serif" style="letter-spacing:0.2px"><i>Box 7911</i></font><font face="verdana, sans-serif" color="#990000"><i><br></i></font></div><div style="font-size:12.8px"><font color="#990000" face="verdana, sans-serif" style="letter-spacing:0.2px"><i>2410 Campus Shore Dr., Raleigh, NC 27606</i></font></div><div style="font-size:12.8px"><a href="mailto:jtmitch5@ncsu.edu" target="_blank"><font face="verdana, sans-serif" color="#990000"><i>jtmitch5@ncsu.edu</i></font></a></div><div style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000"><i>Desk: 919-515-5394</i></font></div><div style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000"><i>Cell: 919-717-7325</i></font></div><div style="font-size:12.8px"><font face="verdana, sans-serif" color="#990000"><i><img src="https://docs.google.com/uc?export=download&id=1QiGLugvY4oVHF_7tSBf4gS9OLOrs_wZf&revid=0B6IsvvpTMVVfZ1Q1Q2gzejVsY3dhRmZ3U3FwdnR5d0x1cWdVPQ" width="96" height="96"><br></i></font></div></div></div></div></div></div></div></div></div>