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<p>Please find the minutes below and at
<a class="moz-txt-link-freetext" href="https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_June_29,_2017#Minutes">https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_June_29,_2017#Minutes</a>
.</p>
<p>_________________________</p>
<div id="mw-content-text" dir="ltr" class="mw-content-ltr" lang="en">
<h2><span class="mw-headline" id="Minutes">Minutes</span></h2>
<p>Present:
</p>
<ul>
<li> <b>FIU</b>: Mahmoud Kamel</li>
<li> <b>JLab</b>: Mark Ito (chair), Eric Pooser, Simon Taylor,
Beni Zihlmann</li>
</ul>
<p>There is a <a rel="nofollow" class="external text"
href="https://bluejeans.com/s/R6Hz4/">recording of this
meeting</a> on the <a rel="nofollow" class="external text"
href="https://jlab.bluejeans.com/">BlueJeans site</a>.
</p>
<h3><span class="mw-headline" id="Efficiency_and_Attenuation">Efficiency
and Attenuation</span></h3>
<p>Mahmoud showed updated results on two topics. Please see <a
rel="nofollow" class="external text"
href="https://halldweb.jlab.org/talks/2017/SC_Meeting_6_29_2017.pdf">his
slides</a> for the details.
</p>
<h4><span class="mw-headline" id="Efficiency">Efficiency</span></h4>
<p>After adjusting his timing cuts for both the signal and the
accidental background, efficiency is back to values we have seen
before, overall about 97% percent.
</p>
<h4><span class="mw-headline" id="Attenuation">Attenuation</span></h4>
<p>The fits to minimum ionizing peaks are now converging nicely.
He finds very reasonable results for peak position as a function
of z-position in the counter, consistent with expectations from
the bench tests at FIU obtained during construction.
</p>
<p>There are still four problem counters that have anomalously low
statistics. Mahmoud will review whether something may have gone
wrong with the timing cut for these counters.
</p>
<h4><span class="mw-headline" id="Mcsmear">Mcsmear</span></h4>
<p>Beni has started looking at comparisons between Monte Carlo and
data for the start counter. Below he plots the time
distributions for the 30 counters; data on top, Monte Carlo
below. Data is significantly wider and is offset in time from
the simulation. This is work in progress; the explanations are
not known at this point. <br>
</p>
<ol>
<li> Data MC comparison, Example of timing for events with no
charged tracks: <br>
DATA: <a
href="https://halldweb.jlab.org/wiki/index.php/File:Sc_paddle_vs_time_DATA.gif"
class="image"><img alt="Sc paddle vs time DATA.gif"
src="https://halldweb.jlab.org/wiki/images/thumb/e/ea/Sc_paddle_vs_time_DATA.gif/300px-Sc_paddle_vs_time_DATA.gif"
width="300" height="228"></a><br>
MC: <a
href="https://halldweb.jlab.org/wiki/index.php/File:Sc_paddle_vs_time_MC.gif"
class="image"><img alt="Sc paddle vs time MC.gif"
src="https://halldweb.jlab.org/wiki/images/thumb/6/65/Sc_paddle_vs_time_MC.gif/300px-Sc_paddle_vs_time_MC.gif"
width="300" height="237"></a></li>
</ol>
<h3><span class="mw-headline" id="NIM_Paper">NIM Paper</span></h3>
<p>Eric has received comments on the draft from Werner. He will
incorporate them as well as the attenuation plots from Mahmoud
when they become available in their final form. He feels on
track for the August 1 deadline.
</p>
<h3><span class="mw-headline" id="Meeting_Time">Meeting Time</span></h3>
<p>We will continue to meet at 11:30 am for the next few meetings.
</p>
</div>
<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
</pre>
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