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I sent these to the wrong list the first time. Sorry for duplicates
if you got them.<br>
<br>
Please find the minutes below and at <a
class="moz-txt-link-freetext"
href="https://halldweb1.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_January_29,_2015#Minutes">https://halldweb1.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_January_29,_2015#Minutes</a>
. Note that these are minutes from a week ago.<br>
_____________________________________________<br>
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GlueX Start Counter Meeting, January 29, 2015<br>
<div id="bodyContent"><span class="mw-headline" id="Minutes">Minutes</span><br>
<ul>
<li> <b>FIU</b>: Werner Boeglin, Mahmoud Kamel </li>
<li> <b>JLab</b>: Eugene Chudakov, Mark Ito (chair), Eric
Pooser, Simon Taylor </li>
</ul>
<br>
<span class="mw-headline" id="Calibration">Calibration</span><br>
<ul>
<li> Mahmoud continues to work on the timing calibration.
</li>
<li> Eric is writing a plugin that selects two paddles
with exactly one hit each to measure time resolution. </li>
<li> Eric is also starting to look at measuring
efficiency. </li>
<li> Werner remarked that we need to associate a start
counter hit with a track for many of these studies.
Eugene noted that we could survey the start counter
using tracks to check the position of the counters. We
could also start using the tagger to nail down timing. </li>
<li> The anomaly at 180 degrees in phi remains. </li>
<li> Simon found the cause of the vertical bands (lines of
constant z) in the distribution of intersection points
between tracks and the start counter when projected in
the r-z plane. They are coming from particles at forward
angles that miss the start counter. The algorithm often
breaks down in these cases. </li>
<li> Simon also understands the "fuzz" in the distribution
on the downstream side of the nose section. This comes
from an overly generous cut in phi to associate tracks
with a counter. Matches with a counter far from the
track in phi put the intersection point outside the
counters. </li>
</ul>
<br>
<span class="mw-headline"
id="Mounting_ST_to_Hydrogen_Target">Mounting ST to
Hydrogen Target</span><br>
<br>
Eric showed <a
href="https://halldweb1.jlab.org/talks/2015/Mounting_ST_to_H2_Target.pdf"
class="external text" rel="nofollow">some slides</a>
illustrating a mechanical problem discovered when an attempt
was made to mount the start counter to the hydrogen target
cart. Bolt heads on the target cart interfere with the start
counter mounting flange. The flange on the target cart is
glued to the scattering chamber[?] and is not easily
replaced. The solution is not clear at this point. We agreed
that we should resist and drilling or grinding on the start
counter assembly. <br>
<br>
We will talk to Tim to make sure he is in the loop in coming
up with a solution and express our opinion that the start
counter should be left alone. <br>
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