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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,_February_9,_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, February 9, 2021, </span><span
class="mw-headline" id="Minutes">Minutes</span></h2>
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lang="en">
<p>Present: Alex Austregesilo, Tegan Beattie, Sean Dobbs,
Mark Ito (chair), Igal Jaegle, Richard Jones, Zisis
Papandreou, Simon Taylor, Nilanga Wickramaarachchi, Beni
Zihlmann
</p>
<p>There is a <a rel="nofollow" class="external text"
href="https://bluejeans.com/s/eCLxtFpOkd5/">recording
of this meeting</a> on the BlueJeans site. Log into
the BlueJeans site first to gain access (use your JLab
credentials).
</p>
<h3><span class="mw-headline" id="Announcements">Announcements</span></h3>
<p>The Collaboration Meeting Agenda has been announced and
there are no slots for HDGeant4-related topics
scheduled. If folks have ideas for topics that should be
presented to the Collaboration, please contact Mark.
</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,_January_26,_2021#Minutes"
title="HDGeant4 Meeting, January 26, 2021">minutes
from January 26</a> without significant comment.
</p>
<h3><span class="mw-headline" id="G3.2FG4_Comparison">G3/G4
Comparison</span></h3>
<p>Tegan presented simulation results on BCAL response
separately for <a rel="nofollow" class="external text"
href="https://halldweb.jlab.org/DocDB/0048/004878/001/FEB05_PiPlusComparison.pdf">charged
pions</a> and <a rel="nofollow" class="external text"
href="https://halldweb.jlab.org/DocDB/0048/004878/001/FEB05_ProtonComparison.pdf">protons</a>.
For each particle type he compared responses with
</p>
<ol>
<li> Standard HDGeant4</li>
<li> The bcal_nolight_heavy_rtj branch of HDGeant4 (NHL)</li>
<li> hdgeant (GEANT3) with HADR1</li>
<li> hdgeant (GEANT3) with HADR4</li>
</ol>
<p>From the discussion:
</p>
<ul>
<li> Particles were generated between 10 and 40 degrees
in polar angle an with momenta from 400 MeV to
2.0 GeV.</li>
<li> The frequency of secondary electrons shows a
difference of almost a factor of two between the two
HDGeant4 simulations with NHL higher than the
standard. We did not come up with a good explanation
for this.</li>
<li> Sean remarked on the long late timing tail for
secondary electrons[?] in HADR1.</li>
<li> Beni suggested making a 2D histogram of the number
of hits in a cluster vs. "BCAL Shower Time - Truth
Shower Time". He was suspicious that the tail may be
coming from single- or few-counter clusters.</li>
<li> Richard wondered how energy thresholds are treated
in the detector "smearing."</li>
<li> Sean suggested looking at individual hit times vs.
the true shower time. This distribution might tell us
something.</li>
<li> For protons there appears to be a difference in the
number of produced neutrons with HADR4 compared to the
same population when plotted as a function of time.
Many of the former and very few of the latter.</li>
<li> Sean and Richard advocated starting to do
comparisons with data. Richard thought that using
exclusive ρ events might give a relatively uniform and
plentiful sample of protons hitting the BCAL. Sean
suggested that Alex pass such a sample on the Tegan
for study.</li>
</ul>
<h3><span class="mw-headline" id="Other_Issues_on_GitHub">Other
Issues on GitHub</span></h3>
<p>We went through <a rel="nofollow" class="external
text"
href="https://github.com/JeffersonLab/HDGeant4/issues">the
list</a>.
</p>
<ul>
<li> <a rel="nofollow" class="external text"
href="https://github.com/JeffersonLab/HDGeant4/issues/182">Incorrect
TAGH counter number assignment</a>. Richard will
have a look.</li>
<li> <a rel="nofollow" class="external text"
href="https://github.com/JeffersonLab/HDGeant4/issues/181">G3/G4
Difference in FDC wire efficiency at the cell
boundary</a> Richard will study this one as well. He
cautioned us that the FDC geometry is not super easy
to navigate.</li>
<li> <a rel="nofollow" class="external text"
href="https://github.com/JeffersonLab/HDGeant4/issues/180">inconsistent
results generated by genBH</a>. Richard was not able
to reproduce the anomalies reported.</li>
<li> <a rel="nofollow" class="external text"
href="https://github.com/JeffersonLab/HDGeant4/issues/167">G4
exceptions for certain run numbers</a>. We need to
follow up with Elton to see if this is still an issue.</li>
</ul>
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