[Halld-offline] HDGeant4 Meeting Minutes, March 26, 2019

[Mark Ito]

Folks,

Please find the minutes here 
<https://halldweb.jlab.org/wiki/index.php/HDGeant4_Meeting,_March_26,_2019#Minutes> 
and below.

   -- Mark

_____________________________________


  Minutes, HDGeant4 Meeting, March 26, 2019

Present:

  * *JLab: * Alex Austregesilo, Thomas Britton, Sean Dobbs, Mark Ito
    (chair),Richard Jones, Simon Taylor

There is a recording of this meeting <https://bluejeans.com/s/96_2v> on 
the BlueJeans site. Use your JLab credentials to access it.


      Review of minutes from the last meeting

We went over the minutes 
<https://halldweb.jlab.org/wiki/index.php/HDGeant4_Meeting,_March_12,_2019#Minutes> 
without significant comment.


      Do-over on comparison studies

Simon has run some single-particle gun simulations for both HDG3 and 
HDG4 on the OSG. He has not had a chance to look at them in detail yet. 
His initial impression is that differences are seen in calorimetry.


      Further comparative studies of calorimeter response

Richard showed some slides 
<https://docs.google.com/presentation/d/1IDw4LD2GhBpzam9E1V8LRBcb49Kb1V3GMTWR2Inw2V8/edit?usp=sharing> 
describing extensions of his work on low-level comparisons of HDG3 and 
HDG4 for calorimetry.

  * He looked at the residual non-linearity, albeit up to 8 GeV, for
    reconstructed shower energy in the FCAL. Agreement between HDG3 and
    HDG4 is very good now, at all energies.
  * He has examined cluster time, relative to "RF". Both HDG3 and 4 show
    the same linear systematic dependence in relative time as a function
    of energy.
  * For BCAL energy response, he showed the same residual non-linearity
    study as shown earlier for the FCAL. Here the qualitative agreement
    is good, with perhaps an 8 MeV upward shift of HDG4 relative to
    HDG3. The effect of energy leakage out the back of BCAL dominates
    the changes in the trends as polar angle moves from far forward to
    90 degrees.
  * For BCAL timing, he noted a difference in the algorithm used to get
    cluster timing between HDG3 and HDG4
      o HDG3 uses energy-weighted average shower times
      o HDG4 uses the earliest hit per sector for times
  * We noted that mcsmear smears the BCAL timing by 55 ps, not a lot.
    Richard sees this in his study.
  * The difference in the BCAL algorithms does not make much apparent
    difference. He suggests we use energy weighted for both to be
    consistent.
  * Richard is planning to deprecate the bcalSiPMUpHit and
    bcalSiPMDownHit elements in HDDM in favor of a single bcalTruthCell
    element that can serve information from both upsteam and downstream
    ends of the BCAL,
  * There is still an issue that Alex sees with the ρ's albeit with
    charged tracks and not electromagnetic showers. Hopefully Simon's
    single-track studies will address it.

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  * This page was last modified on 29 March 2019, at 13:25.

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