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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,_December_13,_2018#Minutes">here</a>
and below.</p>
<p> -- Mark</p>
<p>____________________________________________</p>
<p>
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<h2 id="firstHeading" class="firstHeading" lang="en"><span
dir="auto">GlueX Start Counter Meeting, December 13, 2018,
</span><span class="mw-headline" id="Minutes">Minutes</span></h2>
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lang="en">
<p>Present:
</p>
<ul>
<li> <b> JLab: </b> Mark Ito (chair), Simon Taylor,
Beni Zihlmann</li>
</ul>
<p>There is a <a rel="nofollow" class="external text"
href="https://bluejeans.com/s/EmwBz/">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="Announcements">Announcements</span></h3>
<p>The target will not be changed from LH<sub>2</sub> to
beryllium for the CompCal commissioning period. The
start counter will not be disturbed in the near future.
</p>
<h3><span class="mw-headline"
id="Review_minutes_from_the_meeting_on_November_29_.28SiPM_Monitoring.29">Review
minutes from the meeting on November 29 (SiPM
Monitoring)</span></h3>
<p>We looked over the <a
href="https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_November_29,_2018#Minutes"
title="GlueX Start Counter Meeting, November 29, 2018">minutes
from the previous meeting</a>.
</p>
<p>Since the last meeting Mark spoke to Carl Zorn about
monitoring the health of the SiPMs. He remembers having
concerns about the neutron dose so near the beamline.
Carl pointed out two monitoring methods:
</p>
<ol>
<li> Measuring the dark rate directly by measuring the
rate of single-pixel events with the beam off. In the
lab this is done by looking at ADC data and observing
the the distribution of 1-, 2-,..., n-pixel events. It
is not clear if this can be done in situ in the Hall
with the FADC-250s. The scalar rates with beam off
might show something; this is not clear either. We
need to see if the EPICS scalars were recorded in the
Archiver.</li>
<li> Measure the bias voltage supply current. This will
be roughly proportional to the dark rate. These
currents might be in the Archiver as well.</li>
</ol>
<p>We need to do more research on these approaches. </p>
<h3><span class="mw-headline" id="NIM_Paper">NIM Paper</span></h3>
<p>The December 7th deadline for comments has come and
gone. Eric has produced a new draft, incorporating
comments from Simon, Beni, and Mark. It has been <a
rel="nofollow" class="external text"
href="https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=3497&version=4">posted
on the DocDB as Version 4</a>. Note there are some
minor technical problems with references, but all text
modifications are present.
</p>
<p>After technical corrections, the plan is to announce
this as a final draft to the PID email list and then:
</p>
<ol>
<li> Submit it to the JLab approval process.</li>
<li> Post it the the arXiv.</li>
<li> Submit it to Elsevier.</li>
</ol>
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