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Folks,<br>
<br>
Please find the minutes below and at <a class="moz-txt-link-freetext" href="https://goo.gl/dYg4gJ">https://goo.gl/dYg4gJ</a> .<br>
<br>
-- Mark<br>
__________________<br>
<br>
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<h1 id="firstHeading" class="firstHeading" lang="en"><span
dir="auto">GlueX Start Counter Meeting, June 2, 2016, </span><span
class="mw-headline" id="Minutes">Minutes</span></h1>
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<p>Present:
</p>
<ul>
<li> <b>FIU</b>: Werner Boeglin, Mahmoud Kamel</li>
<li> <b>JLab</b>: Mark Ito (chair), Eric Pooser, Simon
Taylor, Beni Zihlmann</li>
</ul>
<h3><span class="mw-headline" id="Geometry">Geometry</span></h3>
<p>Simon is close to submitting a pull request with new
geometric parameters for the start counter. He is
currently dealing with an overlap issue with the CDC. He
is using the recently done survey as a guide for the
changes. It shows a tilt larger than we thought we had,
0.3 degrees down. (For comparison we had 0.6 degrees in
Fall 2014.) On the upstream end the start counter is 3.4
mm above nominal.
</p>
<p>Simon is also working on widening the cut for matching
charged tracks to the start counter in the nose region.
Previous studies have shown the phi distribution of
tracks at the intersection with the start counter not
centered on the nominal counter center. The shift is not
always in the same direction.
</p>
<h3><span class="mw-headline" id="Calibration">Calibration</span></h3>
<p>After working with Sean to correct the propagation time
calibration implementation, Mahmoud measured time
resolution for three representative runs.
</p>
<table border="border">
<tbody>
<tr>
<th> Run </th>
<th> Sigma (ps)
</th>
</tr>
<tr>
<td> 11366 </td>
<td> 286
</td>
</tr>
<tr>
<td> 11405 </td>
<td> 284
</td>
</tr>
<tr>
<td> 11455 </td>
<td> 293
</td>
</tr>
</tbody>
</table>
<p>He tried running with run-by-run calibrations and did
not see an improvement over the single set of constants
already present in the CCDB (improvement of 3 ps). We
will go ahead and use the single set.
</p>
<h3><span class="mw-headline" id="Efficiency">Efficiency</span></h3>
<p>Mahmoud showed start counter hit efficiency using
crossing charged tracks. If he requires more than 20
hits on the charged track, the efficiency goes up to
99%. Unfortunately, there are not enough tracks in the
forward part of the nose that satisfy this criteria to
get a meaningful efficiency measurement there.
</p>
<h3><span class="mw-headline" id="NIM.2FTDR">NIM/TDR</span></h3>
<p>Eric is back in action in Newport News and will be
working on the NIM paper.
</p>
<h3><span class="mw-headline" id="Swiss_Efficiency">Swiss
Efficiency</span></h3>
<p>Beni noted that the Gotthard Base Tunnel was recently
completed on time and under budget, apropos of nearly
nothing.
</p>
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<li id="lastmod"> This page was last modified on 3 June 2016,
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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
</pre>
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