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<p>Folks,</p>
<p>Please find the minutes <br>
</p>
<p><a moz-do-not-send="true" href="https://halldweb.jlab.org/wiki/index.php/HDGeant4_Meeting,_July_13,_2021#Minutes"></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, July 13, 2021, </span><span class="mw-headline" id="Minutes">Minutes</span></h2>
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<p>Present: Alex Austregesilo, Tegan Beattie, Sean Dobbs,
Mark Ito (chair), Igal Jaegle, Richard Jones, Zisis
Papandreou, Beni Zihlmann
</p>
<p>There is a <a rel="nofollow" class="external text" href="https://bluejeans.com/s/y9dDGYu6ffY/">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="Announcements">Announcements</span></h3>
<p>Mark announced that a new version set with Geant4
10.06.p01 is coming soon. It depends on running
Developers Toolset 8 on CentOS 7.
</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_29,_2021#Minutes" title="HDGeant4 Meeting, June 29, 2021">minutes from
the meeting on June 29th</a>. Action Item #1, "Re-do
comparisons of overall event reconstruction
efficiencies," seemed to us a bit off the critical path.
Rather consistency check of cross sections measured in
data under various conditions, with efficiency
corrections from simulation, seem more important now.
</p>
<h3><span class="mw-headline" id="Adding_Efficiency_as_a_Function_of_Drift_Distance_to_the_FDC_Simulation">Adding
Efficiency as a Function of Drift Distance to the FDC
Simulation</span></h3>
<p>Richard outlined his plan for adding information from
Lubomir Pentchev's Garfield simulation of the FDC. See
his plots starting at 16:40 in the recording. Lubomir
sees a fall off in efficiency at long drift distances.
This effect is not in the simulation. Richard plans to
use the relative drop (and not the absolute level) as a
function of drift distance from Lubomir's curves. He
notes that if one looks at the current discrepancy in
efficiency between data and Monte Carlo, generated by
Alex, the curve from Lubomir appears to be a good
representation of the extra inefficiency seen in data as
a function of drift distance.
</p>
<h3><span class="mw-headline" id="Issues_on_GitHub">Issues
on GitHub</span></h3>
<p>We went through the issues on GitHub. For links to the
issues themselves see the <a rel="nofollow" class="external text" href="https://github.com/JeffersonLab/HDGeant4/issues">issues
page for HDGeant4</a>.
</p>
<ul>
<li> Vertex generation used with BHgen
<ul>
<li> Richard is working on this one. The first step
is to translate an atomic form factor from Ilya
Larin from FORTRAN to C++.</li>
</ul>
</li>
<li> Add incident angle dependence to DIRC mirror
reflectivity
<ul>
<li> This is a request for an enhancement[?].</li>
</ul>
</li>
<li> unknown particle type 50 being generated through
interactions
<ul>
<li> Cerenkov photons in the FCAL is not a bug but a
feature. This one should be closed.</li>
</ul>
</li>
<li> hits in both CALs from the same track
<ul>
<li> Sean reminded us that this is due to the
mathematical track trajectory properly
extrapolated to the FCAL after passing through the
BCAL. Real particles will not do this. Should be
closed.</li>
</ul>
</li>
<li> unexpected jumps in MC yield vs photon energy
<ul>
<li> We are waiting on feedback from Hao Li.</li>
</ul>
</li>
<li> Incorrect TAGH counter number assignment
<ul>
<li> We went to a lot of effort to fix this one. We
marked it as closed.</li>
</ul>
</li>
<li> G3/G4 Difference in FDC wire efficiency at the cell
boundary
<ul>
<li> Richard went through the solution to this issue
in the meeting proper (see above).</li>
</ul>
</li>
<li> G4 exceptions for certain run numbers
<ul>
<li> Elton Smith should review this issue and tell
us if it is still a problem.</li>
</ul>
</li>
<li> Difference in Acceptance between G3 and G4
<ul>
<li> We felt that we have come to the end of this
issue as written. There may be on-going related
mysteries, but those should be re-stated and
entered as new issue. We will ask Colin Gleason if
this one can be closed.</li>
</ul>
</li>
</ul>
<h3><span class="mw-headline" id="Action_Items">Action
Items</span></h3>
<ol>
<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 further about how to get to modern versions
of external software packages.</li>
</ol>
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