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<p>Folks,</p>
<p>Find the minutes below and at
<a class="moz-txt-link-freetext" href="https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_November_17,_2016#Minutes">https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_November_17,_2016#Minutes</a>
.</p>
<p> -- Mark</p>
<p>_________________</p>
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<h2 id="firstHeading" class="firstHeading" lang="en"><span
dir="auto">GlueX Start Counter Meeting, November 17, 2016,
</span><span class="mw-headline" id="Minutes">Minutes</span></h2>
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<p>Present:
</p>
<ul>
<li> <b>FIU</b>: Werner Boeglin, Mahmoud Kamel</li>
<li> <b>JLab</b>: Thomas Britton, Mark Ito (chair)</li>
</ul>
<p>There is a <a rel="nofollow" class="external text"
href="https://bluejeans.com/s/DElZg/">recording of
this meeting</a> on the BlueJeans site.
</p>
<h3><span class="mw-headline" id="Efficiency_Studies">Efficiency
Studies</span></h3>
<p>Mahmoud showed <a rel="nofollow" class="external text"
href="https://halldweb.jlab.org/talks/2016/SC_meeting_Nov17_2016.pdf">results
from his latest efficiency study</a>. Efficiency was
calculated sector by sector. In the denominator are the
number of track intersecting a particular sector. In the
numerator are the number of tracks with matching start
counter hits where the hits have loose cuts defined by
Paul Mattione's SC efficiency tree. Mahmoud then applies
a timing cut (for tracks in the numerator) and a phi
angle cut, measured from the phi at the center of the
counter (again only for track in the numerator). He does
this for various settings of the phi cut. He repeats the
procedure with an additional z "vertex" requirement
(this time in the denominator[?] both[?]). </p>
<p>As the secretary understands it, this yields the
probability that the phi measurement of a track which
fires the start counter is within a particular phi angle
miss amount from the center of the counter, given that
the tracking projects the track to hit that start
counter, whatever that projection criteria may be. We
agreed that this was not exactly efficiency.
</p>
<p>Mahmoud wanted to repeat these studies for various bins
in momentum and z-position (at the start counter[?]),
but did not find those quantities in the tree.
</p>
<p>In the end we did not come to a conclusion on the best
way to characterize efficiency.
</p>
<p>We did agree that a different front should be opened.
As Sean Dobbs had suggested in a previous private
communication, it is important to compare the
"efficiency", however that is defined, between Monte
Carlo and data. That work can start right away, and need
not wait for the ultimate definition of start counter
hit efficiency. As far as that definition is concerned,
Mark thought that a simpler approach might be more
efficient; he will give Mahmoud a call after the meeting
to discuss this.
</p>
<h3><span class="mw-headline" id="Run_Readiness">Run
Readiness</span></h3>
<p>Mark went through Hot Check-Out for the start counter.
Eric Pooser and Mahmoud both looked at the histograms
from the cosmic test run and did not see any anomalies.
</p>
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<pre class="moz-signature" cols="72"><a class="moz-txt-link-abbreviated" href="mailto:marki@jlab.org">marki@jlab.org</a>, (757)269-5295
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