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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,_February_9,_2022#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, February 9, 2022, </span><span
class="mw-headline" id="Minutes">Minutes</span></h2>
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<p>Present: Eugene Chudakov, Paul Eugenio, Mark Ito
(chair), Sasha Ostrovidov, Simon Taylor, Beni Zihlmann
</p>
<p>There is a <a rel="nofollow" class="external text"
href="https://jlab-org.zoomgov.com/rec/share/6qbL5I-czldjb683Py7RhgMF1YpHh18eJ4f0p6jaKzHlbDLpKvUKEOvHI8os1ao.lafz-tPwYNB34s1c">recording
of this meeting</a> on the ZoomGov site. Use passcode:
xut*x!b8 .
</p>
<h3><span class="mw-headline"
id="Review_of_minutes_from_the_last_meeting">Review of
minutes from the last meeting</span></h3>
<p>We went over the <a
href="https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_January_26,_2022#Minutes"
title="GlueX TOF Meeting, January 26, 2022">minutes
from the meeting on January 26th</a>.
</p>
<p>Paul reported on a few points related to the <b>equipment
loan</b>.
</p>
<ul>
<li> Edmundo Barriga is stationed in Newport News, but
will be traveling to Tallahassee for the collaboration
meeting. He will pick up some items covered by the
loan agreement, including the VXS crate, and bring
them back to the Lab.</li>
<li> The bulk of the remaining items are the spare PMTs.</li>
</ul>
<h3><span class="mw-headline"
id="Long-Term_Detector_Health">Long-Term Detector
Health</span></h3>
<p>Sasha presented work he has done to assess the lifetime
of the TOF, in particular the degradation of PMT gain as
a function of time/beam-exposure. See <a rel="nofollow"
class="external text"
href="https://hadron.physics.fsu.edu/~ostrov/tof/2022-02-08/index.pdf">his
slides</a> for the details.
</p>
<p>Some items from the discussion:
</p>
<ul>
<li> Beni: specs on PMT gain as a function of integrated
charge on the last dynode is provided by Hamamatsu.
Integrated charge, in turn, can be estimated by the
from the time integrated rate of minimizing particles.</li>
<li> Paul: we learned a lot from the PMT-relacement
exercise last year. A strategy of identifying weak
tubes and replacing them will help maintain uniform
acceptance of the array.</li>
<li> Beni: he identified candidates for replacement last
year in part by noting PMTs that did not respond with
the expected amount of increased gain with increased
voltage during gain balancing.</li>
<li> Eugene: in general, there are other sources of gain
loss besides degradation of the last dynode, including
damage to the scintillators (surface crazing,
radiation damage) and damage to the voltage ladder in
the PMT base.</li>
<li> Sasha could use a table of the correspondence
between read-out channel and HV channel. Mark will
query his database for this information.</li>
</ul>
<p>Much of this material will be presented at the upcoming
Collaboration Meeting.
</p>
<h3><span class="mw-headline" id="TOF_II_Trigger">TOF II
Trigger</span></h3>
<p>Beni reported that this month has been reserved for
Sascha Somov to do tests on the TOF II trigger. <br>
</p>
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