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<p>Folks,</p>
<p>Please find the minutes <a moz-do-not-send="true"
href="https://halldweb.jlab.org/wiki/index.php/%CE%A0_polarizability_Meeting_Jan_19,_2022#Minutes">here</a>
and below.</p>
<p> -- Mark</p>
<p> _____________________________________</p>
<p>
</p>
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<h1 id="firstHeading" class="firstHeading" lang="en"><span
dir="auto">Π polarizability Meeting Jan 19, 2022, </span><span
class="mw-headline" id="Minutes">Minutes</span></h1>
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lang="en">
<p>Present: Alex Austregesilo, Albert Fabrizi, David
Hornidge, Mark Ito (chair), Nikhil Kalra, Ilya Larin,
David Lawrence, Rory Miskimen, Andrew Schick, Simon
Taylor, Beni Zihlmann
</p>
<p>There is a (partial) <a rel="nofollow" class="external
text"
href="https://jlab-org.zoomgov.com/rec/share/8w89wZ1fWpv57x76H1Teu6glPerQCa5Ew1AVbII4g8sy9qnUrscdjF0AbuykwTW2.UbFFAtUx2xgOEW9u">recording
of this meeting</a> on the ZoomGov website. The
passcode is !&C^z71c
</p>
<h3><span class="mw-headline" id="Action_Items_2">Action
Items</span></h3>
<p>We reviewed the action items.
</p>
<h4><span class="mw-headline"
id="Generate_MC_samples_of_pi.2Bpi-">Generate MC
samples of pi+pi-</span></h4>
<p>David L. reported that he and Andrew have put together
a directory on the work disk,
</p>
<pre>/work/halld/CPP/MC/generated
</pre>
<p>containing three directories at present:
</p>
<pre>BHgen_electron_positron
BHgen_muons
gen_2pi_primakoff
</pre>
<p>There are samples of generated events in each of these
directories that can be used for studies and for
benchmarks of future CPP reconstruction and analysis
code.
</p>
<h3><span class="mw-headline"
id="Make_a_pull_request_for_hdds">Make a pull request
for hdds</span></h3>
<p>Simon reported that Elton merged the pull request last
week. In addition he got new numbers for the MWPCs from
Stephanie Worthington and has put the updated geometry
into the CCDB.
</p>
<h3><span class="mw-headline"
id="Review_CPP_test_run_for_rates_and_check_with_Sasha_on_steps_for_.22replay.22">Review
CPP test run for rates and check with Sasha on steps
for "replay"</span></h3>
<p>Ilya showed slides on his first look at the trigger
test data taken at the end of the SRC run. He is having
trouble analyzing the data. Beni and David will have a
look to see if they can retrieve the trigger bits from
the events. See <a rel="nofollow" class="external text"
href="https://userweb.jlab.org/~ilarin/cpp/1221m10/rcdb.m10.pdf">his
slides</a> for more details.
</p>
<p>Beni also mentioned that when he balanced the gains for
the TOF recently, the average gain was a bit higher than
before. This effectively lower energy threshold may
account for the increase in rate that Ilya saw.
</p>
<h3><span class="mw-headline"
id="Check_with_Hovanes_and_Alexandre_on_using_JD103_diamond">Check
with Hovanes and Alexandre on using JD103 diamond</span></h3>
<p>Rory reported on the recent email exchange that Elton
Smith initiated. It looks like the only option we have
at this point is to use the JD70-103 diamond. Tim sent
around a photo showing it on the goniometer stage. The
consensus is that the the coherent edge from this
diamond may not be very sharp, but that it can provide
adequate polarization to do the experiment. Richard
Jones has suggested a calculation where data from a run
at the light source is convolved with a typical electron
beam profile to calculate the polarization we expect.
Rory will follow up with Richard on what is involved in
doing this calculation.
</p>
<h3><span class="mw-headline"
id="Check_that_Rory.27s_grounding_suggestions_do_not_deteriorate_the_performance_of_Arwen_using_cosmics">Check
that Rory's grounding suggestions do not deteriorate
the performance of Arwen using cosmics</span></h3>
<p>Beni reported on activities with the test set up in the
EEL. On earlier in the week he got the gas turned on and
the DAQ system running. We have been taking data since
yesterday morning at about 20 Hz. He sees nice signals
in the monitoring plots. Next Wednesday we may need to
change the gas bottle. One mystery: he is not seeing
action on the output bubbler.
</p>
<h3><span class="mw-headline"
id="Microscope_move_.28in_progress.29">Microscope move
(in progress)</span></h3>
<p>No one has heard any news from the UConn crew. The
consensus was that this should be interpreted as good
news.
</p>
<h3><span class="mw-headline" id="PID_.2B_AI">PID + AI</span></h3>
<p>David ran the 10 k $pi;$pi; events through his
machinery to produce input for Nikhil to chew on. This
happened just yesterday.
</p>
<h3><span class="mw-headline"
id="CPP_and_NPP_Readiness_Review">CPP and NPP
Readiness Review</span></h3>
<p>Final certification of readiness has been granted by
Physics management.
</p>
<h3><span class="mw-headline"
id="CPP_and_NPP_Experiment_Configuration"><a
href="https://halldweb.jlab.org/wiki/index.php/CPP_and_NPP_Experiment_Configuration"
title="CPP and NPP Experiment Configuration">CPP and
NPP Experiment Configuration</a></span></h3>
<p>We skimmed the <a
href="https://halldweb.jlab.org/wiki/index.php?title=CPP_and_NPP_Experiment_Configuration_document&action=edit&redlink=1"
class="new" title="CPP and NPP Experiment
Configuration document (page does not exist)">CPP and
NPP Experiment Configuration document</a>.
</p>
<p>Beni reported that the cutting of the cable trays on
the forward platform was underway when he was in the
Hall yesterday.
</p>
<h3><span class="mw-headline"
id="Electronic_Configuration">Electronic Configuration</span></h3>
<p>Beni gave us an update on electronics for the chambers
and the new scintillators.
</p>
<ul>
<li> There are plenty of FADC channels for the eight
PMTs</li>
<li> There are also lots of discriminator channels
available.</li>
<li> TDCs are an issue
<ul>
<li> They need an additional connection to the
trigger module[?].</li>
</ul>
</li>
<li> The bottom CAEN HV mainframe has four slots for the
DIRC. The plan is to use two of these for chamber HV
(requires board replacement) and the other two for the
scintillators.
<ul>
<li> Nick Sandoval has test stands appropriate for
both high and low voltage.</li>
</ul>
</li>
</ul>
<p><br>
Rory brought up the idea of a scintillator-only trigger
that could be used for diagnostics for the chambers.
Such a trigger might yield a nice sample of muon pairs.
Beni noted that there was already a NIM crate on the
forward carriage that could be used to form a
front-panel trigger. Though not simple, we thought that
it was within the realm of possibility and the idea
should be explored further.
</p>
<h3><span class="mw-headline" id="Software_consolidation">Software
consolidation</span></h3>
<p>Simon submitted a pull request to merge the CPP branch
of halld_recon onto the master. Sean Dobbs had several
suggestions and Simon is responding to them. For
details, see the <a rel="nofollow" class="external
text"
href="https://github.com/JeffersonLab/halld_recon/pull/616">conversation
on GitHub</a>.
</p>
<h3><span class="mw-headline" id="Next_meeting">Next
meeting</span></h3>
<p>We decided that we should have one. ;-)
</p>
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