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<h1 class="firstHeading">Minutes of the August 25 meeting</h1>
<h3 id="siteSub">From Lowqwiki</h3>
<p>Present: Stephen, Andrea, Hovanes, Aji, Sergey
</p>
<p>On the phone: Kawtar, Raphael, Ahmed, Raffaella
</p>
<p>Notes by Hovanes. </p>
<p><br>
</p>
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<h2>Contents</h2>
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<li class="toclevel-1"><a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_25_meeting#Main_RTPC_status">1 Main RTPC status</a></li>
<li class="toclevel-1"><a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_25_meeting#RTPC_Tests">2 RTPC Tests</a></li>
<li class="toclevel-1"><a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_25_meeting#Readout_Electronics">3 Readout Electronics</a></li>
<li class="toclevel-1"><a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_25_meeting#Gas_handling_system">4 Gas handling system</a></li>
<li class="toclevel-1"><a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_25_meeting#Organizational_issues">5 Organizational issues</a></li>
<li class="toclevel-1"><a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_25_meeting#Other_issues">6 Other issues</a></li>
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<h2> Main RTPC status </h2>
<ul>
<li> Main RTPC is almost complete. Cathode is also in place. RTPC can
now hold high voltage. </li>
</ul>
<ul>
<li> We need to check for the small hole for the gas flow in the
cathode assembly. </li>
</ul>
<ul>
<li> The new RTPC will probably be closed today. But we are still
waiting for the divider and thick sealant. These items are expected to
be here today or tomorrow. </li>
</ul>
<ul>
<li> Cable tray and short tube are here. In principle we can start
transferring cables RTPC this weak, but mostly likely it will happen
sometime next week when we have DAQ components too. </li>
</ul>
<ul>
<li> Before mounting the new RTPC on the cart we need to make sure
that the foil assembly is good because it is hard to remove the foil
when it is already mounted on the cart. </li>
</ul>
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<h2> RTPC Tests </h2>
<ul>
<li> Prototype is still being tested. Neon/DME, He/DME and ArgCO2
were tested, and the signals look pretty good. Neon/DME mixture
produces really good signals on the scope. </li>
</ul>
<ul>
<li> It would be good to try to do track reconstruction for
Neon/DME misture. The constants in the RTPC tracking code would need to
be adjusted for the new gas. </li>
</ul>
<ul>
<li> Stephen will prepare a test plan for the next meeting. </li>
</ul>
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<h2> Readout Electronics </h2>
<ul>
<li> Raffaella gave an update on the <a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Status_of_Readout_Electronics_-_08-25-09"> current status of
the update of the readout electronics</a>. </li>
</ul>
<ul>
<li> After communicating with the experts from CERN Genova
collaborators came to a conclusion that we cannot combine multi-event
readout and sparcified readout. Therefore, we will be using
non-sparcified multi-event mode with zero suppression. In this case we
do not have 200μs deadtime due to list compilation. Raffaella pointed
out that zero-suppression is extremely important because without that
the event rate will decrease by a huge factor. </li>
</ul>
<ul>
<li> Detail studies showed that with 13 cards in each create we can
only achieve 800 Hz event rate on RTPC. Studies showed that if we have
only 4 cards in each crate then the event rate can be up to 2.4KHz
(still depends on the event size). Therefore we would like to use six
crates for which we would need to purchase more components. </li>
</ul>
<ul>
<li> Sergey does not think that we can have 6 computers for
readout. Then he pointed out that we need to test a configuration with
2 branches on a single RORC which we never tried before. Various option
with the number of computers and RORC will need to be considered. </li>
</ul>
<ul>
<li> For more details on what we would need to obtain for the 6-crate
configuration see <a href="http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Status_of_Readout_Electronics_-_08-25-09"> Raffaella's wiki
entry</a>.
</li>
</ul>
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<h2> Gas handling system </h2>
<ul>
<li> The gas panel construction is complete. Some wiring still needs
to be done. </li>
</ul>
<ul>
<li> <a href="http://www.jlab.org/%7Etilles/miniT/Bonus%202009/thumb_index.html">Pictures of the still incomplete panel are available on
Doug' web page. </a>
</li>
</ul>
<ul>
<li> A student from UNH will be here next week to help with the
control system. </li>
</ul>
<ul>
<li> The gas panel will be moved to EEL building at the end of this
week so that we can start leak tests next week. </li>
</ul>
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<h2> Organizational issues </h2>
<ul>
<li> Kawtar reminded us that we need to work on the run plan for EG6.
</li>
</ul>
<ul>
<li> We also need to work out the run coordinators schedule. </li>
</ul>
<ul>
<li> Hall B and accelerator administration need to be informed about
specific requirements for our beam conditions:
</li>
</ul>
<dl>
<dd>
<ol>
<li> Beam current > 200 nA
</li>
<li> Beam energy of single pass in the beginning of the run.
</li>
</ol>
</dd>
<dd>These conditions need to be in experiment's RSAD and/or ESAD. </dd>
</dl>
<ul>
<li> Stepan told the group that the Hall B beam stopper might not
be enough to allow us go to beam currents above 200 nA because the
Faraday cup is capable of handling ~30-40 nA at 6 GeV energy.
Obviously, the presence of the beam stopper will also decrease the
avarage electron energy in the beam, so that limit will be higher for
us. But this needs simulations, and Natasha is currently working on it.
</li>
</ul>
<ul>
<li> Kawtar will work on a draft version of the run plan and we will
discuss it on the following meetings. </li>
</ul>
<p><br>
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<h2> Other issues </h2>
<ul>
<li> Hovanes told the group that according the current plan the CVS
repository for the CLAS offline software will be frozen in September
1st for the transition to the new offline software scheme. These
involves not only transition from CVS to SVN but also restructuring of
the current directory tree and replacement of the "make" scheme with
"scons" scheme. </li>
</ul>
<ul>
<li> The group unanimously expressed their opposition to such a
haste transition because this would require significant manpower in a
time when we need to spent a lot of effort on the commissioning of the
new RTPC.
</li>
</ul>
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