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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_TOF_Meeting,_December_16,_2020#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">GlueX TOF Meeting, December 16, 2020, </span><span
class="mw-headline" id="Minutes">Minutes</span></h2>
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lang="en">
<p>Present: Mark Ito (chair), Simon Taylor, Beni Zihlmann
</p>
<p>There is a <a rel="nofollow" class="external text"
href="https://bluejeans.com/s/uFOTouCmW62/">recording
of this meeting</a>. Log into the <a rel="nofollow"
class="external text"
href="https://jlab.bluejeans.com">BlueJeans site</a>
first to gain access (use your JLab credentials).
</p>
<h3><span class="mw-headline" id="More_on_the_Gain_Study">More
on the Gain Study</span></h3>
<p>We went over additions Beni made to his <a
rel="nofollow" class="external text"
href="https://logbooks.jlab.org/entry/3857729gain">study</a>
since the last meeting. In particular he plotted
amplitude spectra for individual PMTs overlaying the
data from the high intensity and low intensity runs. All
show clear minimum ionizing peaks. The difference in the
mean value in the histograms, reported last time, is
indeed due to taking the average over the entire
histogram, with the high intensity runs having many more
hits a low pulse height, as we speculated last time.
</p>
<p>The anomaly in PMT 69 is revealed as a broad peak in
the pulse height spectrum around 3500 counts. The rate
in this peak seems independent of beam intensity. The
minimum ionizing peak is present in both high and low
intensity runs and at a typical value of pulse height,
so at some level the PMT is working with an unremarkable
gain. It is hard to imagine that a broken light guide is
causing the strange behavior. This tube remains a
candidate for replacement.
</p>
<p>Beni also reported that he has looked at the signal
from PMT 69 on the scope and could not see anything out
of the ordinary.
</p>
<h3><span class="mw-headline" id="Action_Item_Recap">Action
Item Recap</span></h3>
<ol>
<li> Decide on when to ship PMTs to JLab from FSU (Mark,
Paul Eugenio)</li>
<li> Prepare a complete draft of the TOF NIM paper.
(all)</li>
<li> Make a plan for TOF repair during the SAD,
including Paul in the discussion. (all)</li>
</ol>
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