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Hi Holly,</div>
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With this change we have increased the voltage across GEM-3 by 10% compared to before.</div>
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So the voltage across GEM-3 now with 3653 V is like running with something over 4000 V before, which is really, really high. </div>
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Given this I would suggest that we only go up to 3653 in the initial scan. Then check the efficiency curve. If we have reached the plateau, then stop there. If not, we should carefully do the next point at 3697 V, and as soon as we have the data back down.</div>
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We should not go above that </div>
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Best</div>
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Nilanga</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Sbs_gems <sbs_gems-bounces@jlab.org> on behalf of Holly Szumila-Vance <hszumila@jlab.org><br>
<b>Sent:</b> Friday, November 19, 2021 4:09 PM<br>
<b>To:</b> sbs_gems@jlab.org <sbs_gems@jlab.org><br>
<b>Subject:</b> [Sbs_gems] GEM HV scan with new resistors</font>
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<p class="x_MsoNormal"><span style="font-size:11.0pt">Hi Kondo, Nilanga, all, </span>
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<p class="x_MsoNormal"><span style="font-size:11.0pt"> </span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">I realize the voltage scan doesn’t need good alignment, but right now the alignment was showing the new HV layer with about 14% occupancy, which is why I brought up the point about making sure alignment
will be somewhat ready. Andrew says it will be, so we should be able to see in real time if we are getting plateaus.
</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt"> </span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">The HV scan we completed previously consisted of running:</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">3385 (3800 equiv)</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">3430 (3850 equiv)</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">3475 (3900 equiv)</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">3519 (3950 equiv)</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">3564 (4000 equiv)</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">3608 (4050 equiv)</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">3653 (4100 equiv)</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">3697 (4150 equiv)</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">3720 (4175 equiv)</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt"> </span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">Can we reduce some of these points? Should we stay below 3653V or some other limit? These values correspond to the divider before modification.</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt"> </span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">Thanks,</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt">Holly</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt"> </span></p>
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