g4Config.C

Go to the documentation of this file.

// Configuration macro for Geant4 VirtualMC
void Config()
{
    ///    Create the run configuration
    /// In constructor user has to specify the geometry input
    /// and select geometry navigation via the following options:
    /// - geomVMCtoGeant4   - geometry defined via VMC, G4 native navigation
    /// - geomVMCtoRoot     - geometry defined via VMC, Root navigation
    /// - geomRoot          - geometry defined via Root, Root navigation
    /// - geomRootToGeant4  - geometry defined via Root, G4 native navigation
    /// - geomGeant4        - geometry defined via Geant4, G4 native navigation
    ///
    /// The second argument in the constructor selects physics list:
    /// - emStandard         - standard em physics (default)
    /// - emStandard+optical - standard em physics + optical physics
    /// - XYZ                - selected hadron physics list ( XYZ = LHEP, QGSP, ...)
    /// - XYZ+optical        - selected hadron physics list + optical physics
    ///
    /// The third argument activates the special processes in the TG4SpecialPhysicsList,
    /// which implement VMC features:
    /// - stepLimiter       - step limiter (default)
    /// - specialCuts       - VMC cuts
    /// - specialControls   - VMC controls for activation/inactivation selected processes
    /// - stackPopper       - stackPopper process
    /// When more than one options are selected, they should be separated with '+'
    /// character: eg. stepLimit+specialCuts.
    TG4RunConfiguration* runConfiguration = new TG4RunConfiguration("geomRoot", "FTFP_BERT", "stepLimiter+specialCuts");
 
    /// Create the G4 VMC
    TGeant4* geant4 = new TGeant4("TGeant4", "The Geant4 Monte Carlo", runConfiguration);
    cout << "Geant4 has been created." << endl;
 
    /// Create the Specific stack
    CbmStack* stack = new CbmStack(1000);
    stack->StoreSecondaries(kTRUE);
    // stack->SetStartZCut(750.); // run6 exclude ECAL + ZDC
    // stack->SetStartZCut(850.); // run6 exclude ZDC
    // stack->SetMinPoints(0);
    geant4->SetStack(stack);
 
    if (FairRunSim::Instance()->IsExtDecayer()) {
        TVirtualMCDecayer* decayer = new TPythia8Decayer();
        geant4->SetExternalDecayer(decayer);
    }
 
    /// Customise Geant4 setting
    /// (verbose level, global range cut, ..)
    TString configm(gSystem->Getenv("VMCWORKDIR"));
    TString configm1 = configm + "/gconfig/g4config.in";
    cout << " -I g4Config() using g4conf  macro: " << configm1 << endl;
 
    // set the common cuts
    TString cuts = configm + "/gconfig/SetCuts.C";
    cout << "Physics cuts with script \n " << cuts.Data() << endl;
    Int_t cut = gROOT->LoadMacro(cuts.Data());
    if (cut == 0)
        gInterpreter->ProcessLine("SetCuts()");
 
    // set geant4 specific stuff
    geant4->SetMaxNStep(10000);   // default is 30000
    geant4->ProcessGeantMacro(configm1.Data());
 
    // Activate the parameters defined in tracking media
    // (DEEMAX, STMIN, STEMAX), which are, be default, ignored.
    // In Geant4 case, only STEMAX is taken into account.
    geant4->SetUserParameters(kTRUE);
}