[Halld-offline] HDGeant4 Meeting Minutes, February 12, 2019

[Mark Ito]

Folks,

Please find the minutes here 
<https://halldweb.jlab.org/wiki/index.php/HDGeant4_Meeting,_February_12,_2019#Minutes> 
and below.

   -- Mark

________________________


  HDGeant4 Meeting Minutes, February 12, 2019

Present:

  * *CMU: * Naomi Jarvis
  * *JLab: * Thomas Britton, Mark Ito (chair), Simon Taylor, Beni Zihlmann
  * *UConn: * Richard Jones

Today's meeting did not follow the published agenda.

Mark has tagged a *version of HDDS that uses the pre-DIRC geometry* 
found in the CCDB. Recall that this version has overlaps removed and 
includes the Lucite shield in front of the TOF. The new tag is 3.14. 
Mark will prepare a version set using it for general use.

Thomas has looked at the plots of the recent *HDG3 vs 4 comparison 
simulation and does not see any concerning differences.* These were done 
with most physics processes turned off (no multiple scattering, etc.). 
He will re-run with all physics processes turned on as a further check. 
Naomi reported that she had seen HDG4 executing many times more slowly 
that HDG3 several months ago. Thomas will look at the execution times 
when he does the running.

Peter Pauli has done a *detailed high-level comparison of results from 
HDG3 and HDG4.* He has been on owl shift and could not be at the meeting 
to present his results. He did send his slides to Mark. Find them here 
<http://nuclear.gla.ac.uk/~pauli/pres.pdf>. We will hear from him at a 
future meeting.

We discussed the nature of the advice Thomas should give at his talk at 
the Collaboration Meeting vis-a-vis readiness of HDG4 for prime time. We 
agreed that *we can recommend use of HDG4 going forward now;* no known 
problems exist. In particular, tuning of the smearing should now be done 
against HDG4 so that that effort will transmit to future efforts. 
Richard made the point that we are now in a situation where, if HDG3 and 
HDG4 give different results, it may not be the case that HDG3 is "right" 
and HDG4 is "wrong." For example, there are processes in Geant4 that are 
better modeled than they were in GEANT.

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  * This page was last modified on 12 February 2019, at 16:59.

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