Minutes for LArSoft coordination meeting on April 10, 2018


Vito Di Benedetto, Giuseppe Cerati, Lynn Garren, Krzysztof Genser, Herbert Greenlee, Tom Junk, Kyle Knoepfer, Gianluca Petrillo, Erica Snider, Hans Wenzel


Bruce Baller, Erin Conley, Aaron Higuera, Katherine Lato, Saba Sehrish, Gleb Sinev, Filippo Varanini

Project status report [Erica Snider]

  • proposing to upgrade to GNU C++ 7.3 (e17) after adopting art 2.11
  • art 2.11 also has e15
  • [Gianluca Petrillo] we are interested in feedback on resource usage of Clang builds compared to GCC ones
  • [Lynn Garren] Is clang build needed for SLF6? [Herbert Greenlee] Why ? [Lynn Garren] so that it can be checked that the code compiles with it.
  • [Lynn Garren] what experiments think of the idea of setting up gallery together with LArSoft? [Herbert Greenlee] MicroBooNE already does [Tom Junk] that would save some potential conflicts


  • v06_73_00 will the last release supported for El Capitan
  • experiments are no requiring a SLF7 binary distribution with c2 qualifiers
  • acceptance of the idea of upgrading GCC compiler
  • We will send out a survey form to find out what development platform is used
    • [Bruce Baller] uses OSX native development environment (XCode)

Requirements for a new LArSoft event display [Erica Snider]

  • plan to evaluate options for an improved event display (2018 LArSoft Workplan)
    • including a demonstrator with some key features
    • expect variant of model-view-controller or model-view-presenter pattern
    • unlikely for LArSoft to have effort to put into the development and implementation
  • a document with the proposed requirements is available on google doc
  • [Filippo Varanini] feature: displaying wave forms in the frequency domain
  • [Filippo Varanini] how is the event display managing information from different detectors? [Erica Snider] photo detector systems need to be integrated too; in general, all relevant data stored as data products (not only from TPC) should be supported; the goal is to have a framework that can be extended easily to support new data
  • [Filippo Varanini] will provide feedback based on experience with the ICARUS event display
  • [Giuseppe Cerati] sharing event displays via links are essential for reporting issues and collaboration


  • encouraging people caring for event displaying to take a look to the requirements in the google doc
    • send comments to larsoft-team@fnal.gov

Update on LArG4 refactoring [Hans Wenzel]

  • a goal is to separate propagation through detector from charge and light transportation
  • more complete exposure and access to Geant4 abilities
  • scintillation also from outside the TPC field cage
  • ability to plug in scintillation and ionisation models (possibly correlated)



Request for an update to Geant4 version in LArSoft [Aaron Higuera]

  • Geant4 10.3 patch 1 has charge kaon cross sections not matching modern experimental data and models: this is a bug
  • patch 3 solves the bug
  • [Erica Snider] what else has changed in Geant4 10.3? [Krzysztof Genser] this being a patch release, no physics change is expected that is not a bug
  • [Bruce Baller] is this affecting only charged kaons? neutral kaons are an important background for proton decay studies [Hans Wenzel] yes, as the data used is from charge kaons, although neutral kaon might be improving as well
  • [Hans Wenzel] Geant4 is always eager to receive feedback on comparison between experiment data and Geant4 simulation


  • LArSoft will start the regular upgrade path, asking for approval
  • the earliest this might happen is next week release