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Dear all,<br>
<br>
On behalf of eg6 group I want to thank Hovanes for his valuable<br>
contribution to the setup and running of the eg6 experiment and<br>
for his leadership in the data calibration till now. Lets wish him a<br>
good luck and success in his new position as Hall D staff.<br>
I hope he will find time to contribute to the eg6 in the future.<br>
<br>
Stepan <br>
<br>
On 8/31/10 11:44 AM, Hovanes Egiyan wrote:
<blockquote cite="mid:4C7D2354.8080406@gmail.com" type="cite">
<h1 class="firstHeading">Minutes of the August 31 meeting</h1>
<h3 id="siteSub">From Lowqwiki</h3>
<p>Present: Bayram, Dave, Stepan, Hovanes
</p>
<p>On the phone: Raphael, Raffaella, Will
</p>
<p>Notes by Hovanes.
</p>
<table class="toc" id="toc">
<tbody>
<tr>
<td>
<div id="toctitle">
<h2>Contents</h2>
[<a moz-do-not-send="true" href="javascript:toggleToc()">hide</a>]</div>
<ul>
<li class="toclevel-1"><a moz-do-not-send="true"
href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_31_meeting#Announcements">1
Announcements</a></li>
<li class="toclevel-1"><a moz-do-not-send="true"
href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_31_meeting#EC_timing">2
EC timing</a></li>
<li class="toclevel-1"><a moz-do-not-send="true"
href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_31_meeting#Solenoid">3
Solenoid</a></li>
<li class="toclevel-1"><a moz-do-not-send="true"
href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_31_meeting#Hodoscope">4
Hodoscope</a></li>
</ul>
</td>
</tr>
</tbody>
</table>
<p>
</p>
<div class="editsection">[<a moz-do-not-send="true"
href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_August_31_meeting&action=edit&section=1">edit</a>]</div>
<h2>Announcements</h2>
<ul>
<li> Hovanes will start working for Hall D this fall and will
not
be able to continue performing the dutie of the analysis
coordinator.
Stepan agreed to be the eg6 analysis coordinator. </li>
</ul>
<p><br>
</p>
<div class="editsection">[<a moz-do-not-send="true"
href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_August_31_meeting&action=edit&section=2">edit</a>]</div>
<h2> EC timing </h2>
<ul>
<li> Bayram looked at 6 GeV cooked data and he came to concluion
that they do not need more calibrations, at least for the next
cooking
pass. </li>
<li> There was a small issue with 1.2 GeV timing when <a
moz-do-not-send="true"
href="http://clasweb.jlab.org/rungroups/lowq/wiki/images/9/93/EC_TIMING_61441.pdf">
he looked at run 61441</a>.
There was ~100ps offset for EC time with respect to SC time
although
the start times from both EC and SC were at zero. </li>
<li> An attempt to calibrate EC timing with 1.2 GeV data itself
was not successful because because there were no hits in large
areas of
EC because of the CLAS configuration for low energy runs. </li>
<li> It was decided to keep only two calibration points for EC
timing. </li>
</ul>
<p><br>
</p>
<p><br>
</p>
<div class="editsection">[<a moz-do-not-send="true"
href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_August_31_meeting&action=edit&section=3">edit</a>]</div>
<h2>Solenoid</h2>
<ul>
<li> Hovanes <a moz-do-not-send="true"
href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Solenoid_update_31Aug2010">
compared the 3 solenoid field maps</a>: </li>
</ul>
<dl>
<dd>
<ol>
<li> The DC tracking FPACK map </li>
<li> Solenoid field map currently being used in <b>gem</b>
package </li>
<li> Field map sent by Eric </li>
</ol>
</dd>
</dl>
<ul>
<li> His conclusion is that there is a bug in the tracking code
when reading the field map. It creates 0.5cm offset in Z and
R-directions. </li>
<li> This needs to be checked by cooking data. It would be good
to check e1dvcs data on proton with and without "fixing" the
bug and
see if there is improvement in the elastic event angle and
vertex
matching. </li>
<li> We need a map with known current at the power supply and
clearly identified format (preferably FPACK file similar to
what is
being used in DC tracking now). </li>
</ul>
<div class="editsection">[<a moz-do-not-send="true"
href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_August_31_meeting&action=edit&section=4">edit</a>]</div>
<h2> Hodoscope </h2>
<ul>
<li> Wiil studied <a moz-do-not-send="true"
href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Aug31_hodo">
the ADC spectra for pedestals and production runs</a>. </li>
<li> The ADC spectrum for the eg6 pedestal runs is drastically
different from what Mikhail Yurov had from previous CLAS
periods. </li>
<li> It seems like the HV were off during the pedestal runs.
Therefore this particular run is useless even for pedestals
extractions. </li>
<li> Stepan suggested to look at the plot of energy (ADC) vs
timing (TDC) and use cuts on these plane to select out-of-time
hits to
get the pedestal and the single photoelectron peak. </li>
<li> Dave performed <a moz-do-not-send="true"
href="http://www.jlab.org/%7Ejenkins/eg6/31aug10/31aug10.html">studies
to identify π<sup>0</sup> in IC/SH</a>. </li>
<li> Dave looked at the time difference between hits in IC and
CLAS. He sees two peaks, and he interprets the peak at -2ns as
the
events with correct timing and places cut around it. </li>
<li> He also uses energy corrections provided by F.-X. and looks
at
2-γ pairs. </li>
<li> Looking at the occupancy of the hodoscope he also see the
missing segment due to HV channel being off. </li>
<li> Dave also uses cuts on the energy versus time plots to
select
in-time events in hodoscope. When he does it he sees that ~8%
of pions
produce hits in the hodoscope, which is more or less
consistent with
what Mikhail Yurov found (~5%). </li>
</ul>
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