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<p class="MsoNormal">3653 for layers 0,2 and new 3. The back tracker has had no changes.
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b><span style="font-size:12.0pt;color:black">From: </span></b><span style="font-size:12.0pt;color:black">Sbs_gems <sbs_gems-bounces@jlab.org> on behalf of Andrew Puckett <puckett@jlab.org><br>
<b>Date: </b>Thursday, November 18, 2021 at 3:43 PM<br>
<b>To: </b>"Liyanage, Nilanga K (nl8n)" <nl8n@virginia.edu>, "Jeffas, Sean (sj9ry)" <sj9ry@virginia.edu>, "sbs_gems@jlab.org" <sbs_gems@jlab.org><br>
<b>Subject: </b>Re: [Sbs_gems] [EXTERNAL] UV GEM HV Settings<o:p></o:p></span></p>
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<p class="MsoNormal">Okay, so then what are the recommended settings for ALL UVA layers/modules? I’m confused. Because we have been running with a mix of 3653 and 3697<o:p></o:p></p>
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<p class="MsoNormal">Andrew<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:12.0pt;color:black">From:
</span></b><span style="font-size:12.0pt;color:black">Sbs_gems <sbs_gems-bounces@jlab.org> on behalf of Liyanage, Nilanga K (nl8n) <nl8n@virginia.edu><br>
<b>Date: </b>Thursday, November 18, 2021 at 3:30 PM<br>
<b>To: </b>Jeffas, Sean (sj9ry) <sj9ry@virginia.edu>, sbs_gems@jlab.org <sbs_gems@jlab.org><br>
<b>Subject: </b>Re: [Sbs_gems] [EXTERNAL] UV GEM HV Settings</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">HI Sean,</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black"> </span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">No, I think it would be best to run at 3653 V with this modified divider for right now. </span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black"> </span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">We are going to study the modified divider with the x_ray source here over the new couple of weeks. Once we know more, we can consider going higher if needed</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black"> </span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">Best</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black"> </span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">Nilanga</span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="color:black">From:</span></b><span style="color:black"> Sbs_gems <sbs_gems-bounces@jlab.org> on behalf of Sean Jeffas <sj9ry@virginia.edu><br>
<b>Sent:</b> Thursday, November 18, 2021 3:22 PM<br>
<b>To:</b> sbs_gems@jlab.org <sbs_gems@jlab.org><br>
<b>Subject:</b> [Sbs_gems] [EXTERNAL] UV GEM HV Settings</span> <o:p></o:p></p>
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<p class="MsoNormal">Hi Kondo and Nilanga, <o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">After we changed the resistor on UV GEM layer 0 back in October Kondo recommended to lower the HV a bit to monitor the GEM HV. Here is the logbook reference <a href="https://logbooks.jlab.org/entry/3930480">https://logbooks.jlab.org/entry/3930480</a>.
However we discovered this week that the voltage has never been returned to 3697 V since then, and we ran all this week at 3653 V. From Kondo's log it is my impression that he meant to only set it to 3653 V for a few hours. Is it ok to change to 3697 V at
this point? Also with the two other UV GEMs in BB we also have these new dividers. Then ran all night at 3653 V with cosmics with no issues. Can we set those to 3697 V as well?<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Best,<br>
Sean<o:p></o:p></p>
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