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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/HDGeant4_Meeting,_June_15,_2021#Minutes">here</a>
and below.</p>
<p> -- Mark</p>
<p> ____________________________________</p>
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<h2 id="firstHeading" class="firstHeading" lang="en"><span dir="auto">HDGeant4 Meeting, June 15, 2021, </span><span class="mw-headline" id="Minutes">Minutes</span></h2>
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<p>Present: Tegan Beattie, Mark Ito (chair), Igal Jaegle,
Richard Jones, Zisis Papandreou, Simon Taylor, Beni
Zihlmann
</p>
<p>There is a <a rel="nofollow" class="external text" href="https://bluejeans.com/s/p6T6qFBFPEj/">recording
of this meeting</a> on the BlueJeans site. Log into
the <a rel="nofollow" class="external text" href="https://jlab.bluejeans.com">BlueJeans site</a>
first to gain access (use your JLab credentials).
</p>
<h3><span class="mw-headline" id="Review_of_minutes_from_the_last_meeting">Review of
minutes from the last meeting</span></h3>
<p>We went over the <a href="https://halldweb.jlab.org/wiki/index.php/HDGeant4_Meeting,_June_1,_2021#Minutes" title="HDGeant4 Meeting, June 1, 2021">minutes from
the meeting on June 1st</a>. Richard has been working
on changing the build system for Diracxx to use CMake.
He is already using CMake for his stand-alone HDDM
package (not to be confused with src/libraries/HDDM in
halld_recon, this package corresponds to
src/programs/Utilites/hddm in halld_recon). Mark
mentioned that he has built stand-alone HDDM in
preparation for breaking it out from halld_recon.
</p>
<h3><span class="mw-headline" id="Charged_hadron_timing_in_the_BCAL">Charged hadron
timing in the BCAL</span></h3>
<p>Tegan reported that he tried the tighter χ<sup>2</sup>
cut suggested last time; he did not see a difference
from the nominal cut. Sean Dobbs made a suggestion that
Tegan start to look at pions in the BCAL. To that end he
is getting set up to do a comparison of π<sup>−</sup>Δ<sup>++</sup>
between simulation and data. He has collected some files
from Jon Zarling already.
</p>
<h3><span class="mw-headline" id="FDC_efficiency_modeling">FDC
efficiency modeling</span></h3>
<p>Richard is working on incorporating the efficiency
curves produced from Garfield studies by Lubomir
Pentchev into the simulation. The per layer hit
efficiency is better than that in data at present; this
should help.
</p>
<h3><span class="mw-headline" id="The_Schick_Effect_and_FCAL_LEDs">The Schick Effect
and FCAL LEDs</span></h3>
<p>We briefly discussed how we might study the Schick
effect, discussed at the last meeting. Using the LEDs to
track gains in the FCAL modules appears to be difficult.
</p>
<h3><span class="mw-headline" id="Alternate_models_for_electromagnetic_shower_generation_in_Geant4">Alternate
models for electromagnetic shower generation in Geant4</span></h3>
<p>Richard called our attention to the four different
options that can be chosen for simulating E&M
showers in Geant4. We use option 1, which is good for
100 GeV electrons and photon. Option 4 (code name
Livermore) on the other hand is said to be good at 10
GeV, though it might be more calculationally expensive.
He plans on introducing an option so the user can choose
among these models for future studies.
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<h3><span class="mw-headline" id="Action_Items">Action
Items</span></h3>
<ol>
<li> Re-do comparisons of overall event reconstruction
efficiencies.</li>
<li> Think about how to study the Schick-Smith-Dalton
effect(s). (all)</li>
<li> Think about a GlueX Doc on simulation. (all)</li>
<li> Think about how to get to modern versions of
external software packages. (all)</li>
</ol>
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