<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
Folks,<br>
<br>
Find the minutes below and at <a class="moz-txt-link-freetext" href="https://goo.gl/oSkcUo">https://goo.gl/oSkcUo</a> .<br>
<br>
-- Mark<br>
_____________________<br>
<div id="globalWrapper">
<div id="column-content">
<div id="content" class="mw-body" role="main">
<h1 id="firstHeading" class="firstHeading" lang="en"><span
dir="auto">GlueX Start Counter Meeting, June 30, 2016, </span><span
class="mw-headline" id="Minutes">Minutes</span></h1>
<div id="bodyContent" class="mw-body-content">
<div id="mw-content-text" dir="ltr" class="mw-content-ltr"
lang="en">
<p>Present:
</p>
<ul>
<li> <b>FIU</b>: Mahmoud Kamel</li>
<li> <b>JLab</b>: Mark Ito (chair), Simon Taylor, Beni
Zihlmann</li>
<li> <b>NU</b>: Sean Dobbs</li>
</ul>
<h3><span class="mw-headline" id="Update_on_Efficiencies">Update
on Efficiencies</span></h3>
<p>Mahmoud presented <a rel="nofollow" class="external
text"
href="https://halldweb.jlab.org/talks/2016/ST_meeting_June30_2016.pdf">slides
on the latest results</a> from his efficiency studies.
He used a ROOT tree produced from the start counter
efficiency plugin run as part of the production
reconstruction pass on the Spring 2016 data. A single
file was analyzed. See his slides for the plots. His
slides covered:
</p>
<ul>
<li> criteria for selection of charged tracks in the
study</li>
<li> histograms of some global properties of the tracks
and start counter hits</li>
<li> start counter efficiencies for all tracks: 98%</li>
<li> histograms of the same global properties when a phi
cut is applied to tracks to keep them away from the
edges of the counters (delta phi cut)</li>
<li> efficiencies with the delta phi cut: 99%</li>
<li> same efficiencies for the straight section: 99%</li>
<li> for the bend section: 99%</li>
<li> and for the nose section: 99%</li>
<li> the studies were repeated for protons, pi+, pi-,
and K+</li>
<li> for K+ no start counter misses were found when the
delta phi cut was applied; the study was repeated
without the cut</li>
</ul>
<p>Efficiencies are everywhere (almost incredibly) high.
</p>
<h3><span class="mw-headline" id="Calibration">Calibration</span></h3>
<p>We asked Mahmoud to think about documenting the
calibration procedure in a cookbook-like fashion so that
future students will be able to reproduce it.
</p>
<h3><span class="mw-headline" id="Dark_Rate_Monitoring">Dark
Rate Monitoring</span></h3>
<p>Beni brought us the issue of monitoring dark rate of
the SiPMs. We don't have a regular procedure for doing
so. This is important given the start counter's
proximity to the beamline and Yi Qiang's study that
degradation can occur with exposure to the beam. We will
have to develop a way to keep track of this.
</p>
<h3><span class="mw-headline" id="Mcsmear_Parameters">Mcsmear
Parameters</span></h3>
<p>Sean reminded Mark and Simon that they promised to come
up with a sensible parametrization for the smearing
function.
</p>
<p>He also mentioned that there is no run-dependent time
resolution currently in the CCDB. Mahmoud has seen
evidence for small shifts, but has not done a detailed
time-dependence study. He will have a look, hopefully
before the end of July.
</p>
</div>
<div class="printfooter">
Retrieved from "<a dir="ltr"
href="https://halldweb.jlab.org/wiki/index.php?title=GlueX_Start_Counter_Meeting,_June_30,_2016&oldid=75962">https://halldweb.jlab.org/wiki/index.php?title=GlueX_Start_Counter_Meeting,_June_30,_2016&oldid=75962</a>"</div>
</div>
</div>
</div>
<div id="footer" role="contentinfo">
<ul id="f-list">
<li id="lastmod"> This page was last modified on 30 June 2016,
at 13:53.</li>
</ul>
</div>
</div>
<br>
<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>
</body>
</html>