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<h1 class="firstHeading">Minutes of the May 11 meeting</h1>
<h3 id="siteSub">From Lowqwiki</h3>
<p>Present: Hovanes, Stepan
</p>
<p>On the phone: Eric, Yohann, Lamiaa, Raphael, Dave
</p>
<p>Notes by Hovanes.
</p>
<p><br>
</p>
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<h2>Contents</h2>
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<ul>
<li class="toclevel-1"><a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_May_11_meeting#TOF_status">1 TOF status</a></li>
<li class="toclevel-1"><a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_May_11_meeting#IC_related_issues">2 IC related issues</a></li>
<li class="toclevel-1"><a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_May_11_meeting#Elastic_calibrations_with_H2">3 Elastic calibrations
with H2</a></li>
<li class="toclevel-1"><a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_May_11_meeting#RTPC_calibrations">4 RTPC calibrations</a></li>
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<h2> TOF status </h2>
<dl>
<dd> Lamiaa and Hovanes gave an <a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Status_of_TOF_on_May_11_2010"> update on the TOF system
calibrations</a>.
<ul>
<li> Lamiaa set the RF offset to zero for 61695 and the run was
recooked. </li>
<li> She recalibrated the paddle-to-paddle offset for this run
with modified <i>p2p_delay_el</i> program with RF-time taken from <b>HEVT</b>
bank. </li>
<li> After updating the CALDB and recooking the same run the TOF
overall resolution is on the order of 160ps. </li>
<li> Some paddles are still off and they will need to be taken
care of manually.
</li>
<li> Since there were beam tune changes during eg6 run the
RF-offset may need to be calibrated for a few runs. </li>
<li> On unrelated note, Stepan pointed out that EC time
information is not available.
</li>
</ul>
</dd>
</dl>
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<h2> IC related issues </h2>
<ul>
<li> There were no updates on IC calibrations.
</li>
<li> Dave Jenkins is looking for π<sup>0</sup>s
and ηs in the data. </li>
</ul>
<dl>
<dd>
<dl>
<dd>He could see π<sup>0</sup>s in
EC. He would like to also satrt looking into π<sup>0</sup>s
in IC. </dd>
<dd>Dave wants an event generator to simulate π<sup>0</sup>s and ηs
to check his programs. Stepan suggested <i>fsgen</i> phase space
generator. It is easy to use, but an input file needs to be modified
for desired channel and kinematics. </dd>
</dl>
</dd>
</dl>
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<h2> Elastic calibrations with H<sub>2</sub> </h2>
<dl>
<dd> Eric continues studying <a href="http://clasweb.jlab.org/rungroups/lowq/wiki/images/1/1e/Eric_05112010.pdf"> elastic scattering
kinematics on hydrogen target</a> using the nominal beam energy of <i>E</i><sub><i>e</i></sub> = 1.2067GeV and
detected electron parameters.
<ul>
<li> He sees sector dependence on the position of the missing
mass and excitation energy versus sector. </li>
<li> Five sectors are shifted to one side, except sector 2 for
which the peaks are at the right location. </li>
<li> Stepan will check if <i>E</i><sub><i>e</i></sub>
= 1.2067GeV matches the "Tiefenback number" in the BOS files. </li>
<li> Stepan suggested to also look at θ-dependence of the peak
positions.
</li>
<li> Eric also wanted to know if the magnetic field map we are
using in the reconstruction is consistent with Saclay field map. </li>
</ul>
</dd>
</dl>
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<h2> RTPC calibrations </h2>
<dl>
<dd> Raphael studied the <a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/First_drift_path_observations"> drift paths in eg6 RTPC</a>
using single pass events on helium target.
<ul>
<li> He compared the the z- and &\phi; position from the pads
to the positions from the tracks he swam starting from the point given
by electrons. </li>
<li> At this point he assumes a linear dependence between the
radial position of the hit positions and the TDC values. </li>
<li> He sees a constant 5mm shift in the z-coordinate. </li>
<li> There is also nonlinearity in the φ vs TDC dependence which
Raphael interprets as the nonlinearity between R and TDC. </li>
<li> He will try to fit this dependence and see what happens in
the next iterations.
</li>
</ul>
</dd>
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