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<p>Folks,</p>
<p>Please find the minutes <a moz-do-not-send="true"
href="https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_January_10,_2019#Minutes">here</a>
and below.</p>
<p> -- Mark</p>
<p>________________________________________</p>
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<h2 id="firstHeading" class="firstHeading" lang="en"><span
dir="auto">Minutes, GlueX Start Counter Meeting, January
10, 2019</span></h2>
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lang="en">
<p>Present:
</p>
<ul>
<li> <b> FIU: </b> Werner Boeglin, Mahmoud Kamel</li>
<li> <b> JLab: </b> Thomas Britton, Mark Ito (chair),
Simon Taylor, Beni Zihlmann</li>
</ul>
<p>There is a <a rel="nofollow" class="external text"
href="https://bluejeans.com/s/UEwUD">recording of this
meeting</a> on the <a rel="nofollow" class="external
text" href="https://jlab.bluejeans.com/">BlueJeans
site</a>. Use your JLab credentials to authenticate.
</p>
<h3><span class="mw-headline"
id="Review_minutes_from_the_meeting_on_December_13">Review
minutes from the meeting on December 13</span></h3>
<p>We went over <a
href="https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_December_13,_2018#Minutes"
title="GlueX Start Counter Meeting, December 13, 2018">the
minutes</a> and noted that the plan is to do the DIRC
commissioning with the liquid hydrogen target and start
the PrimEx run with beryllium.
</p>
<h3><span class="mw-headline"
id="Calibration_and_Efficiency">Calibration and
Efficiency</span></h3>
<p>Sean recently implemented the use of Mahmoud's new
z-dependent resolution parametrization in <a
rel="nofollow" class="external text"
href="https://github.com/JeffersonLab/halld_recon/pull/76">halld_recon</a>]
and <a rel="nofollow" class="external text"
href="https://github.com/JeffersonLab/halld_sim/pull/27">halld_sim</a>.
</p>
<h3><span class="mw-headline" id="SiPM_bias_currents">SiPM
bias currents</span></h3>
<p>Beni has looked into using the SiPM bias-voltage-supply
current as a method to monitor radiation damage. He
found that these currents have been recorded in the
EPICS Archiver. The current if very small, there is a
noticeable increase year-to-year by a few percent,
roughly consistent from channel-to-channel. He reminded
us that each supply channel serves then four SiPM's that
read-out one start counter paddle.
</p>
<p>We should compare the observed behavior with the BCAL.
We should also check with Carl Zorn that the absolute
magnitude of the current seen in the Archiver is
reasonable.
</p>
<p>Werner mentioned that another way to monitor dark rate
is to look at pedestal widths of the ADC's.
</p>
<h3><span class="mw-headline" id="NIM_Paper">NIM Paper</span></h3>
<p>Mark reported that Eric Pooser has pushed the paper
through the Lab approval process, submitted it the the
arXiv, and submitted it to NIM. Just this morning Eric
reported that the arXiv has assigned a temporary
submission identifier, submit/2531925. He also reports
that NIM has assigned a reviewer, Peter Krizan, and a
manuscript number, NIMA-D-19-00031.
</p>
<h3><span class="mw-headline" id="Maintenance">Maintenance</span></h3>
<p>We discussed ideas for insuring reliable operation of
the start counter going forward.
</p>
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