void runMCFOPISphere(Int_t field,
		     TString gas,
		     Int_t gain,
		     TString outdir,
		     int nEvents=5000,
		     Int_t run = 1,
		     unsigned int seed=0,
		     TString addon="") {

  // ------------------------------------------------------------------------
  gRandom->SetSeed(seed);
  
  // ========================================================================
  // Verbosity level (0=quiet, 1=event level, 2=track level, 3=debug)
  Int_t iVerbose = 1;
  FairRunSim *fRun = new FairRunSim();
  
  // set the MC version used
  // --------------------------------------------------
  TString mcMode = "TGeant3";
  fRun->SetName(mcMode);

  TString jobdir=outdir;
  int length = jobdir.Length();
  if(jobdir[length-1] != "/")
    jobdir.Append("/");
  
  TString jobname=Form("Cosmics_FopiMC_%i%s%i_%i.mc.root",field,gas.Data(),gain,run);

  
  TString outfile = jobdir+jobname;
  std::cout<<outfile<<std::endl;
  fRun->SetOutputFile(outfile);
  std::cout<<"Set output file to "<<outfile<<std::endl;

  TString copy = outfile;
  TString parfile = copy.ReplaceAll("mc.root","param.root");
  TString digifile = gSystem->Getenv("VMCWORKDIR");
  digifile += Form("/tpc/FOPI/par/tpc.%i%s%iMC",field,gas.Data(),gain);
  digifile += addon;
  digifile += ".par";
  cout<<digifile<<endl;

  cout<<"getting rundb\n";
  FairRuntimeDb *rtdb=fRun->GetRuntimeDb();
  FairParAsciiFileIo* parIo1 = new FairParAsciiFileIo();
  cout<<"opening parfile\n";
  parIo1->open(digifile.Data(),"in");
  rtdb->setFirstInput(parIo1);
  Bool_t kParameterMerged=kTRUE;

  cout<<"setting par output\n";
  FairParRootFileIo* parOut=new FairParRootFileIo(kParameterMerged);
  parOut->open(parfile.Data());
  rtdb->setOutput(parOut);
  


  // In general, the following parts need not be touched
  // ========================================================================


  // -----   Timer   --------------------------------------------------------
  cout<<"start timer\n";
  TStopwatch timer;
  timer.Start();
  // ------------------------------------------------------------------------


  // Set Material file Name
  //-----------------------
  cout<<"setting materials\n";
  fRun->SetMaterials("media_pnd.geo");
  
  // Create and add detectors
  //-------------------------
  cout<<"creating digipar\n";
  TpcDigiPar* par = (TpcDigiPar*) rtdb->getContainer("TpcDigiPar");
  par->setInputVersion(fRun->GetRunId(),1);
  par->setChanged(kTRUE);
  par->init();
 
  Double_t taroff = -65;
  Double_t targetpos = taroff+41.;
  // possible materials: copper (default), lead, carbon
  TString targetmat = TString("copper");
  TString alignmentFileName = par->getAlignmentFile();
  std::cout<<"Using Alignment File: "<<alignmentFileName<<"\n";

  TFile* geotmp =new TFile("geometry/FOPI_TPC.root","READ");
  if(geotmp->IsOpen())
    {
      std::cout<<"geofile exists already\n";
      geotmp->Close();
    }
  else
    {
      TString  command;
      command.Form(".! root -b -q  '$PANDAPATH/macro/tpc/FOPI/make_TPC_geo.C(true,\"%s\")'",alignmentFileName.Data());
      cout<<command<<endl;
      gROOT->ProcessLine(command);
    }
  FairModule *Cave= new PndCave("CAVE");
  Cave->SetGeometryFileName("pndcave.geo");
  fRun->AddModule(Cave);

  TpcDetector *Tpc = new TpcDetector("TPC", kTRUE);
  Tpc->SetGeometryFileName("FOPI_TPC.root");
  Tpc->SetMixture("TPCFOPI_mix"); // TPCFOPI_mix: Ar CO2 (90/10)
  if(mcMode=="TGeant3") Tpc->SetAliMC();
  //Tpc->SetAllSensitive(kTRUE);
  fRun->AddModule(Tpc);

  FairPrimaryGenerator* primGen = new FairPrimaryGenerator();
  fRun->SetGenerator(primGen);

  FairBoxGeneratorMOD* boxGen = new FairBoxGeneratorMOD(13,1);
  boxGen->SetPRange(2,10.); // GeV/c (2,10)
  boxGen->SetRandAntiPart();
  
  boxGen->SetSphere(90,0,0,36.4);
  boxGen->SetShift(-16,16,-16,16,-43,43);
  //boxGen->SetThetaRange(90.,90.);
  boxGen->SetThetaRange(0.,180.);
  //boxGen->SetPhiRange(0.,360.);
  boxGen->SetPhiRange(90.,90.);
  //boxGen->SetDebug(kTRUE);

  primGen->AddGenerator(boxGen);

  // Create and Set Magnetic Field
  // --------------------
  // Constant Field
  //PndConstField *fMagField=new PndConstField();
  //fMagField->SetField(0., 0. , 0. ); // values are in kG
  //fMagField->SetFieldRegion(-50, 50,-50, 50, -2000, 2000); // values are in cm
  Double_t taroff= -65;
  FOPIField * fMagField = new FOPIField(0.616);
  fMagField->SetTargetOffset(taroff);
  fRun->SetField(fMagField);
   
  /**Initialize the session*/
  fRun->Init();

  rtdb->saveOutput();
  rtdb->print();

  // Transport nEvents
  // -----------------
  fRun->Run(nEvents);


  timer.Stop();
  Double_t rtime = timer.RealTime();
  Double_t ctime = timer.CpuTime();
  cout << endl << endl;
  cout << "Macro finished succesfully." << endl;
  cout << "Output file is "    << outfile << endl;
  cout << "Parameter file is " << parfile << endl;
  cout << "Real time " << rtime << " s, CPU time " << ctime << " s" << endl;
  cout << endl;
  // ------------------------------------------------------------------------


}