<div dir="ltr">Hi All,<div><br></div><div>I scrolled through the logbook and found we had sparks causing > 20 uA jumps three times total in the past week of running. Therefore it seems like a rare spark to me, and should not cause any issues, and does not need any action. We chose our current operating voltages at the very beginning of the plateau so I think it would be a significant change to decrease any of them by 50 V.</div><div><br></div><div>Best,</div><div>Sean</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Dec 6, 2021 at 3:51 PM Gnanvo, Kondo (kg6cq) <<a href="mailto:kg6cq@virginia.edu">kg6cq@virginia.edu</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">
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<p class="MsoNormal">Hi all, <u></u><u></u></p>
<p class="MsoNormal">I think we should be clear on what we are discussing here! <u></u>
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<li class="gmail-m_-6284437974280400217MsoListParagraph" style="margin-left:0in">What I saw on the logbook looks like a spark from me and I don’t really think it is something to worry about. We expect that with GEMs unless there is a specific pattern with that
spike and in that case we should take ab look and try to understand. I would suggest that GEM expert look at the chart and come with a clear conclusion on that
<u></u><u></u></li></ul>
<p class="gmail-m_-6284437974280400217MsoListParagraph"><u></u> <u></u></p>
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<li class="gmail-m_-6284437974280400217MsoListParagraph" style="margin-left:0in">Reducing HV for 50 V because of APV saturation is a discussion that we had yesterday , so I will not repeat the argument here but let’s try not to mix issues and solution we apply
to try to address. <u></u><u></u></li></ul>
<p class="gmail-m_-6284437974280400217MsoListParagraph"><u></u> <u></u></p>
<p class="MsoNormal">Best regards <u></u><u></u></p>
<p class="MsoNormal">Kondo<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal"><b>From:</b> Sbs_gems <<a href="mailto:sbs_gems-bounces@jlab.org" target="_blank">sbs_gems-bounces@jlab.org</a>> <b>On Behalf Of
</b>David Flay<br>
<b>Sent:</b> Monday, December 6, 2021 3:46 PM<br>
<b>To:</b> Liyanage, Nilanga K (nl8n) <<a href="mailto:nl8n@virginia.edu" target="_blank">nl8n@virginia.edu</a>>; <a href="mailto:sbs_gems@jlab.org" target="_blank">sbs_gems@jlab.org</a><br>
<b>Subject:</b> Re: [Sbs_gems] [New Logentry] Brief Voltage Spike on uva_xygem_2<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal" style="background:white"><span style="font-size:12pt;color:black">Thanks Nilanga,<u></u><u></u></span></p>
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<p class="MsoNormal" style="background:white"><span style="font-size:12pt;color:black"><u></u> <u></u></span></p>
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<p class="MsoNormal" style="background:white"><span style="font-size:12pt;color:black">Zeke and I will do that before we start the next run. <u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black">Best regards,<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black">David <u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black"><u></u> <u></u></span></p>
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<p class="MsoNormal" style="background:white"><span style="font-size:12pt;color:black">----------------------------------------------------------------</span><span style="font-size:12pt"><u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black">David Flay, Ph. D.<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black">Hall A/C Staff Scientist<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black">Thomas Jefferson National Accelerator Facility<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black">Office: CEBAF Center, C119<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black">----------------------------------------------------------------<u></u><u></u></span></p>
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<p class="MsoNormal" style="margin-bottom:12pt"><span style="font-size:12pt;color:black"><u></u> <u></u></span></p>
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<p class="MsoNormal"><b><span style="color:black">From:</span></b><span style="color:black"> Liyanage, Nilanga K (nl8n) <<a href="mailto:nl8n@virginia.edu" target="_blank">nl8n@virginia.edu</a>><br>
<b>Sent:</b> Monday, December 6, 2021 3:37 PM<br>
<b>To:</b> David Flay <<a href="mailto:flay@jlab.org" target="_blank">flay@jlab.org</a>>; <a href="mailto:sbs_gems@jlab.org" target="_blank">
sbs_gems@jlab.org</a> <<a href="mailto:sbs_gems@jlab.org" target="_blank">sbs_gems@jlab.org</a>><br>
<b>Subject:</b> [EXTERNAL] Re: [Sbs_gems] [New Logentry] Brief Voltage Spike on uva_xygem_2</span>
<u></u><u></u></p>
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<p class="MsoNormal"> <u></u><u></u></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black">Hmmm, that is a bit worrying.<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black"><u></u> <u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black">I think, until we understand this a bit more, we should back down the HV on just this one module by 50 V.<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black"><u></u> <u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black">I expect the reduction of efficiency to be very small because of this change. So I think we should do this soon.<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black"><u></u> <u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black">Best<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black"><u></u> <u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12pt;color:black">Nilanga<u></u><u></u></span></p>
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<p class="MsoNormal"><b><span style="color:black">From:</span></b><span style="color:black"> Sbs_gems <<a href="mailto:sbs_gems-bounces@jlab.org" target="_blank">sbs_gems-bounces@jlab.org</a>> on behalf of
<a href="mailto:flay@jlab.org" target="_blank">flay@jlab.org</a> <<a href="mailto:flay@jlab.org" target="_blank">flay@jlab.org</a>><br>
<b>Sent:</b> Monday, December 6, 2021 3:20 PM<br>
<b>To:</b> <a href="mailto:sbs_gems@jlab.org" target="_blank">sbs_gems@jlab.org</a> <<a href="mailto:sbs_gems@jlab.org" target="_blank">sbs_gems@jlab.org</a>><br>
<b>Subject:</b> [Sbs_gems] [New Logentry] Brief Voltage Spike on uva_xygem_2</span><span style="font-size:9.5pt;font-family:"Trebuchet MS",sans-serif">
<u></u><u></u></span></p>
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<h1><span style="font-size:12pt;font-family:"Trebuchet MS",sans-serif"><a href="https://logbooks.jlab.org/entry/3957495" target="_blank"><span style="text-decoration:none">Brief Voltage Spike on uva_xygem_2
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<span style="font-size:6.5pt;font-family:"Trebuchet MS",sans-serif"><a href="https://logbooks.jlab.org/entry/3957495/delete?destination=email/send" target="_blank"><span style="text-decoration:none">Delete</span></a><u></u><u></u></span></li></ul>
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<b><span style="font-size:5.5pt;font-family:"Trebuchet MS",sans-serif">Lognumber <a href="https://logbooks.jlab.org/entry/3957495" target="_blank">
<span style="text-decoration:none">3957495</span></a>. Submitted by <a href="https://logbooks.jlab.org/user/flay" target="_blank">
<span style="text-decoration:none">flay</span></a> on <a href="https://logbooks.jlab.org/entries?start_date=1638818252&end_date=1638825452&book=HALOG" target="_blank">
<span style="text-decoration:none">Mon, 12/06/2021 - 15:17</span></a>. <u></u><u></u></span></b></p>
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<p><span style="font-size:6.5pt;font-family:"Trebuchet MS",sans-serif;color:white">Just catching up on this after the DAQ has settled back in and the HCAL HV was power cycled.
</span><span style="font-size:6.5pt;font-family:"Trebuchet MS",sans-serif"><u></u><u></u></span></p>
<p><span style="font-size:6.5pt;font-family:"Trebuchet MS",sans-serif">At around 13:50 we had a HV spike on uva_xygem_2, see attached.<u></u><u></u></span></p>
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