void CreateSttHits() {

  Int_t nevt = 0;

  // Input file (real events)
  TString inFile = "output.root";

  // Parameter file
  TString parFile = "geoparams.root";

  // Digitisation file (ascii)
  TString digiFile = "all.par";

  // t0 offset file 
  TString t0File = "toffset.dat";

  // calib file 
  TString calibFile = "rt_fitparams.dat";

  // Output file
  TString outFile = "digi_real.root";

  // -----   Timer   --------------------------------------------------------
  TStopwatch timer;

  // -----   PndSttHitProducer  ---------------------------------------------
  FairRunAna *fRun= new FairRunAna();
  fRun->SetInputFile(inFile);
  fRun->AddFriend("geo.root");
  fRun->SetOutputFile(outFile);
  fRun->SetWriteRunInfoFile(kFALSE);

  FairRuntimeDb* rtdb = fRun->GetRuntimeDb();
  FairParRootFileIo* parInput1 = new FairParRootFileIo();
  parInput1->open(parFile.Data(), "UPDATE");
  rtdb->setFirstInput(parInput1);
  Bool_t kParameterMerged=kTRUE;

  PndSttHitProducerReal* hitpr = new PndSttHitProducerReal();
  hitpr->SetVerbose(0);
  // choose calib:
  // 1 = Garfield parameters
  // 2 = parameters from experimental calib
  Int_t flag = 2;
  hitpr->SetCalib(flag);
  if (flag==2) {
    Bool_t Calib = kFALSE;
    Calib = hitpr->ReadCalib(calibFile);
    if (Calib==kFALSE) 
      exit(0);
  }
  Bool_t t0 = kFALSE;
  t0 = hitpr->ReadToffset(t0File);
  if (t0 == kFALSE)
    exit(0);
  fRun->AddTask(hitpr);


  rtdb->setOutput(parInput1);
  // ------------------------------------------------------------------------

  // --------------------------------------------------------------------------
  fRun->Init();
  timer.Start();
  fRun->Run(0, nevt);

  // -----------  Save the parameters ----------------- 
  rtdb->saveOutput();
  rtdb->print();

  // -----   Finish   -------------------------------------------------------
  timer.Stop();
  Double_t rtime = timer.RealTime();
  Double_t ctime = timer.CpuTime();
  cout << endl << endl;
  cout << "Macro finished successfully." << endl;
  cout << "Parameter file is " << parFile << endl;
  cout << "Real time " << rtime << " s, CPU time " << ctime << " s" << endl;
  cout << endl;
}