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<p>Folks,</p>
<p>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,_August_1,_2018#Minutes">https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_August_1,_2018#Minutes</a></p>
<p> -- Mark</p>
<p>______________________________</p>
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<h1 id="firstHeading" class="firstHeading" lang="en"><span
dir="auto">Minutes, GlueX TOF Meeting, August 1, 2018</span></h1>
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lang="en">
<p>Present:
</p>
<ul>
<li> <b> FSU: </b> Sasha Ostrovidov</li>
<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/57knh/">recording of
this meeting</a> on the BlueJeans site. Use your JLab
credentials.
</p>
<ol>
<li> Announcements</li>
<li> Review of <a
href="https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_July_18,_2018#Minutes"
title="GlueX TOF Meeting, July 18, 2018">minutes
from the July 18 meeting</a></li>
</ol>
<h3><span class="mw-headline"
id="Review_of_minutes_from_the_July_18_meeting">Review
of minutes from the July 18 meeting</span></h3>
<p>We reviewed the <a
href="https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_July_18,_2018#Minutes"
title="GlueX TOF Meeting, July 18, 2018">minutes</a>.
</p>
<h4><span class="mw-headline"
id="Study_of_amplified_base_performance">Study of
amplified base performance</span></h4>
<p>Beni followed Sasha's suggestion from last time and
repeated method 3 using paddle 31 rather than 14. 31 is
on the opposite side of the array, farther away from the
test PMT. He compiled the results, along with those from
paddle 14, in <a rel="nofollow" class="external text"
href="https://halldweb.jlab.org/talks/2018/specialtof.pdf">an
updated version of hist note</a>. There is a
significant reduction in time resolution when using 31
versus 14.
</p>
<p>Sasha suggested that some combination of methods 1 and
2 might give more robust results.
</p>
<p>The overall conclusion remains the same, that
resolution from the amplified base is not as that from a
regular base.
</p>
<h3><span class="mw-headline" id="Geometry_.26_Alignment">Geometry
& Alignment</span></h3>
<p>Prompted by Sean's presentation of parametrizations for
geometry corrections for the TOF, Beni looked at
measuring these corrections using charged particles. For
each track he takes the TOF point closest to the
projection of the track to the TOF. The projection
position is used to update a 2D histogram, with separate
histograms for each TOF paddle, as reported by the TOF
point. The procedure was done separately for positive
and negative tracks. See <a rel="nofollow"
class="external text"
href="https://halldweb.jlab.org/talks/2018/tof_plots/">his
plots in the talks directory</a> and <a
rel="nofollow" class="external text"
href="https://halldweb.jlab.org/talks/2018/paddlepos.pdf">his
draft note describing the study</a> for details.
</p>
<p>Straight lines are fit separately for each half of the
paddle (left/right or upper/lower). May paddles give
fits inconsistent with one straight line describing both
halves. This is especially true for the half-length
paddles, as might be expected, but also for the
full-length paddles. The simplest geometry-correction
scheme may not be adequate.
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