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<p>Folks,</p>
<p>Please find the minutes below and at</p>
<p>
<a class="moz-txt-link-freetext" href="https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_May_9,_2018#Minutes">https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_May_9,_2018#Minutes</a></p>
<p> -- Mark</p>
<p>_________________________________</p>
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<h2 id="firstHeading" class="firstHeading" lang="en"><span
dir="auto">GlueX TOF Meeting, May 9, 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> 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/QgH4H/">recording of
this meeting</a> on the BlueJeans site. Use your JLab
credentials.
</p>
<h3><span class="mw-headline"
id="Review_of_minutes_from_the_April_11_meeting">Review
of minutes from the April 11 meeting</span></h3>
<p>We went over the <a
href="https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_April_11,_2018#Minutes"
title="GlueX TOF Meeting, April 11, 2018">minutes from
the April 11</a>.
</p>
<ul>
<li> The TOF threshold scan has not been fully analyzed
yet.</li>
<li> Beni reminded us that in addition to the change in
ADC threshold, we changed the NSA read-out parameter
from 25 to 15. This occurred a bit after the threshold
change. He thinks we may want to move to NSA = 10 in
the future.</li>
<li> With these changes (threshold and NSA) the
monitoring plots show significant improvement in
efficiency (based on charge track projections). The
efficiency curves as a function of distance of radius
are wider and flatter than they used to be.</li>
<li> Beni also mentioned that if he can get all of the
software ready, he may make a presentation on
comparing TOF efficiency between data and Monte Carlo.</li>
</ul>
<h3><span class="mw-headline" id="Calibration_Status">Calibration
Status</span></h3>
<p>Beni gave the report.
</p>
<ul>
<li> A significant portion of the first half of the run
has been calibrated.</li>
<li> The first run after the read-out parameter changes
is missing from the set of calibrated runs.</li>
<li> Calibration of the second half is waiting on
production of the input ROOT files.</li>
<li> Calibrations should appears soon after appearance
of the ROOT files. The process has been automated and
does not take long to run.</li>
<li> New constants have not been added to the database.</li>
</ul>
<h3><span class="mw-headline"
id="Amplified_Base_Prototype">Amplified Base Prototype</span></h3>
<p>Beni gave the report.
</p>
<ul>
<li> Beni has not been able to get decent calibration
results from the amplified base channel. The problem
is not known at present.</li>
<li> Mark speculated that these difficulties may have
something to do with the large baseline shift in this
channel, and software that does not accommodate this
shift.</li>
</ul>
<h3><span class="mw-headline" id="Re-configuring_the_TOF">Re-configuring
the TOF</span></h3>
<p>Beni has been reviewing the concept for a TOF upgrade,
in particular a new counter arrangement near the
beamline, that <a rel="nofollow" class="external text"
href="https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=3432">Paul
Eugenio presented</a> at the collaboration meeting in
October 2017. The design has a larger beam hole than the
current TOF.
</p>
<p>Beni thinks that if we go to the new configuration, we
can go to high rates without having to resort to the
amplified bases. The counters that <em>would</em> have
been overwhelmed at high rate would simply no longer be
there.
</p>
<p>He outlined some issues <em>assuming</em> we go this
way:
</p>
<ul>
<li> A decision has to be made soon to allow time for
procurement and construction in advance of
installation during the Summer, 2019.</li>
<li> New paddles would have to be constructed. Some are
of dimensions we have not made before.</li>
<li> Light guides would have to be redesigned for the
half-width paddles. The current design will not
accommodate more that two such counters in a row and
we will have fourteen consecutive half-width'ers in
the new design.</li>
<li> More electronic read-out and HV channels will have
to be procured.</li>
<li> The software geometry will have to be changed. Also
both reconstruction and simulation software will have
to be modified (unless the software engineering for
the TOF portions are already of professional-grade
quality).</li>
</ul>
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<pre class="moz-signature" cols="72">--
Mark Ito, <a class="moz-txt-link-abbreviated" href="mailto:marki@jlab.org">marki@jlab.org</a>, (757)269-5295
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