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Virtual MC, Geant4

Virtual MC, Geant4. I. Hrivnacova, IPN, Orsay ALICE Offline Meeting, CERN, 4 March 2003. Outline. Virtual MC Example E03 TMCVerbose Performance tests New VMC users RootToG4 Geant4 Release 5.0. Virtual MC Examples E01, E02.

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Virtual MC, Geant4

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  1. Virtual MC, Geant4 I. Hrivnacova, IPN, Orsay ALICE Offline Meeting, CERN, 4 March 2003

  2. Outline • Virtual MC • Example E03 • TMCVerbose • Performance tests • New VMC users • RootToG4 • Geant4 • Release 5.0 ALICE Offline Meeting, CERN, 4 March 2003

  3. Virtual MCExamples E01, E02 • Geant4 novice example N01, N02 rewritten with usage of the Virtual Monte Carlo • E01 • Builds simple geometry, tracks geantino and prints info at each step • E02 • Builds parameterised geometry with magnetic field, tracks proton, registers hits in a tracker and saves hits and kinematics in a Root file • Default cuts in each MC (different) –> different results ALICE Offline Meeting, CERN, 4 March 2003

  4. Virtual MCNew E03 • E03: • Builds geometry with divided volumes, with magnetic field • Primary particles: e- with (optionally) randomised position and fixed direction • Calorimeter hits – total energy deposit and track length in the absorber and gap layers • Storing hits, particles stack • Using E02 Root manager class • Verbosity (usage of TMCVerbose) • Same cuts -> Comparable results • G4: cut in range 1mm + /run/particle/applyCuts • G3: cuts in kin. energy set to correspond to G4 cut ALICE Offline Meeting, CERN, 4 March 2003

  5. Virtual MCNew E03 ALICE Offline Meeting, CERN, 4 March 2003

  6. Virtual MCNew E03 • Some setting in the G4 example N03 could not be ported to VMC: • Material from elements and/or other materials (mixture of mixtures) • Gas in non STP conditions • Update geometry • New example of particles stack class • Simpler, only reference from daughter to mother • Better performance ALICE Offline Meeting, CERN, 4 March 2003

  7. Virtual MCTMCVerbose • Inspired by verbose in Geant4 • /tracking/verbose command enables a user to run Geant4 with printing a detailed information from each step • Very useful for debugging, understanding what is going on • TMCVerbose – new class in root/mc • For each TVirtualMCApplication function a corresponding function is defined in TMCVerbose • Defined levels of output: 0 – 3 • If level = 0 – no printing ALICE Offline Meeting, CERN, 4 March 2003

  8. Virtual MCTMCVerbose Usage • Including MC Verbose in MC application is not automatic • User can add calls to MC verbose in some/all MC application functions; Eg. void Ex03MCApplication::Stepping() { // User actions at each step fVerbose.Stepping(); fCalorimeter->ProcessHits(); } • Suggestion: to be included in AliRun in AliRoot ALICE Offline Meeting, CERN, 4 March 2003

  9. Virtual MCTMCVerbose Output **************************************************************************************************** Particle = gamma Track ID = 13 Parent ID = 4 **************************************************************************************************** Step# X(cm) Y(cm) Z(cm) KinE(MeV) dE(MeV) Step(cm) TrackL(cm) Volume Process # 0 -6.634 -0.228 -0.067 0.6481 0.0000 0.000 0.000 ABSO No active process # 1 -6.500 -0.280 -0.134 0.6481 0.0000 0.159 0.159 ABSO Transportation # 2 -6.500 -0.280 -0.134 0.6481 0.0000 0.000 0.159 GAPX Transportation # 3 -6.000 -0.475 -0.385 0.6481 0.0000 0.592 0.751 GAPX Transportation # 4 -6.000 -0.475 -0.385 0.6481 0.0000 0.000 0.751 ABSO Transportation # 5 -5.758 -0.569 -0.506 0.0000 0.0880 0.287 1.038 ABSO Photoelectric effect **************************************************************************************************** Particle = e- Track ID = 14 Parent ID = 13 **************************************************************************************************** Step# X(cm) Y(cm) Z(cm) KinE(MeV) dE(MeV) Step(cm) TrackL(cm) Volume Process # 0 -5.758 -0.569 -0.506 0.5601 0.0000 0.000 0.000 ABSO No active process # 1 -5.755 -0.570 -0.503 0.0551 0.1598 0.010 0.010 ABSO Bremstrahlung # 2 -5.755 -0.570 -0.503 -0.0000 0.0551 0.001 0.011 ABSO Energy loss ALICE Offline Meeting, CERN, 4 March 2003

  10. Virtual MCPerformance test • E03 • enables to compare performance of G3, G4 VMC and G4 (native) on a simple geometry & physics problem • Test: • 50 events • 1000 primary e-, 50 MeV • 10 layers: 1cm Lead + 0.5 cm Liquid Argon • Default material (world): vacuum • EM physics • G3: LOSS=1, DRAY=1, HADR=0 • G4: TG4 EM Physics Constructor ALICE Offline Meeting, CERN, 4 March 2003

  11. Virtual MCPerformance test • Geant4 VMC configurations: • TG4SteppingAction, TG4TrackingAction on/off • These classes insure performing special steps of zero length for new track and on boundary • Magnetic field on/off • Saving secondaries to MC stack on/off • If comparing with native G4 simulation be aware that G4 does not make secondaries persistent ALICE Offline Meeting, CERN, 4 March 2003

  12. Performance testG4 VMC Configurations ALICE Offline Meeting, CERN, 4 March 2003

  13. Virtual MCPerformance test results ALICE Offline Meeting, CERN, 4 March 2003

  14. Virtual MCPerformance test results • G3/G4: • 0.60 • Cuts in G4 • Production treshold • Not tracking cut – particles are tracked till stopping • G4 VMC / G4 native: • 1.25 in standard VMC application • 1.11 if no need to perform specials steps at boundary, new track ALICE Offline Meeting, CERN, 4 March 2003

  15. Virtual MCPerformance test results • No field/ Mag. Field: • G3: 1.0 • G4 native: 6.13 !! • If vacuum changed to air: 1.18 • G4 VMC: 1.27 • In low density materials G4 VMC defines automatically limited step • In G4 user can customize accuracy parameters of magnetic field – not yet passed to Geant4 VMC • Saving secondaries in MC Stack (c4/c3): • 1.29 • Now optional – can be switched off if not needed ALICE Offline Meeting, CERN, 4 March 2003

  16. Virtual MCNew users • OPERA • Neutrino oscillations, international collaboration • CBM • Nucleus-nucleus collision program at the future accelerator facility, GSI, Darmstadt • Considering of building simulation based on VMC • Proposal by CBM • Meetings of VMC users with VMC developers per ~ 3 months ALICE Offline Meeting, CERN, 4 March 2003

  17. Virtual MCNew users (requirements) • Need/Would like to have • User defined particles, ions • Gspart in TGeant3 has to be revised • Ions as primary particles • Customisable G4 VMC physics list • Available already now, but requires to add infrastructure and documentation • More documentation • eg. on mapping G4 physics processes to TMCProcess • G4 visualisation (Open Inventor driver) • Root geometry modeller -> VMC ALICE Offline Meeting, CERN, 4 March 2003

  18. Virtual MCNew users (contribution) • Have done • Geant4 VMC HTML source code documentation • Available at: http://www-linux.gsi.de/~gsisim/geant4_vmc • By D. Bertini, GSI, using Doxygen • To be linked/included at VMC Web ALICE Offline Meeting, CERN, 4 March 2003

  19. RootToG4 Convertor • Convertor from Root TGeo geometry to Geant4 geometry • Independent from Geant4 VMC • Usable also for native Geant4 application • Will be used by Geant4 VMC • To support the new way of defining geometry with direct usage of TGeo in a user VMC application • In development, already operational • Geometries from examples gexam1, gexam3, gexam4 have been successfully converted • Not yet available from VMC site ALICE Offline Meeting, CERN, 4 March 2003

  20. RootToG4 ConvertorPresent Status • Supported • Shapes, Volumes, Positions, Materials, Divisions • TArb8 not supported by Geant4 • Divisions temporarily implemented as multiple G4PVPlacement (to be revised when G4Divison is available) • To be done • Medias (using G3toG4), Boolean shapes • Not to be supported • Overlapping volumes (not supported by Geant4) ALICE Offline Meeting, CERN, 4 March 2003

  21. RootToG4 Convertor g2root roottog4 g4toxml Geant3 -> Root TGeo -> Geant4 -> GraXML ALICE Offline Meeting, CERN, 4 March 2003

  22. Geant4 5.0 • Release 5.0 – 13 Dec 2003 • Patch01 – 25 Feb 2003 • Geant4-05-00-beta-02 • From Release notes: • First release of the cascade part of the HETC re-write • First release of the binary-cascade (kinetic) model • First implementation of HepMC interfaces • Implementation of abstract layer for persistency; removed ODBMS specific implementations and setup • Example for use of Root: examples/extended/persistency/PersEx01 ALICE Offline Meeting, CERN, 4 March 2003

  23. Geant4 5.0 • From Release notes (cont): • Compilation of g3tog4 optional (G4USE_G3TOG4) • Has to be set by Geant4 VMC users • New G4Exception scheme based on severity level • G4RunManager: introduced ResetNavigator() method (could be useful for Flugg ?) • … ALICE Offline Meeting, CERN, 4 March 2003

  24. Geant4 5.0 J.P.Wellish, GSI, Feb 2003 ALICE Offline Meeting, CERN, 4 March 2003

  25. J.P.Wellish, GSI, Feb 2003 ALICE Offline Meeting, CERN, 4 March 2003

  26. J.P.Wellish, GSI, Feb 2003 ALICE Offline Meeting, CERN, 4 March 2003

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