// Example for SAMURAI BPC
void BPCHist(){

  // set raw data file
  TArtEventStore *eventstore = new TArtEventStore;
  const char* filename = "ridf/sdaq02/dayone0080.ridf";//22C+C run
  if(!eventstore->Open(filename)){
    std::cout << "cannot open " << filename << std::endl;
    return;
  }

  // calibration parameters
  TArtSAMURAIParameters *smprm = TArtSAMURAIParameters::Instance();
  smprm->LoadParameter("db/SAMURAIBPC.xml");

  // TArtStoreManager is a class for accessing calibrated data
  TArtStoreManager *sman = TArtStoreManager::Instance();

  // calibration class
  TArtCalibBPCHit *calibbpc = new TArtCalibBPCHit;

  // define histograms
  TH1* hid = new TH1I("hid", "BPC ID", 128, 0.5, 128.5);
  TH1* hlayertdc  = new TH2D("hlayertdc", "BPCLayer-TDC", 2,-0.5,1.5, 4100, 0, 4100);
  TH1* hx = new TH1D("hx", "BPC X", 200,-150,150);

  // event loop
  int nevent = 0;
  while(eventstore->GetNextEvent() && nevent<10000){
    calibbpc->ReconstructData();

    //--------------------------------------------------------
    // Get BPC hit information
    TClonesArray *bpchits = 
      (TClonesArray *)sman->FindDataContainer("SAMURAIBPCHit");

    if ( bpchits != 0 ){
      Int_t nhit = bpchits->GetEntries();

      if ( nhit > 0 ){
	Double_t pos_sum = 0;
	for (Int_t i=0; i<nhit; i++){
	  TArtDCHit *hit = (TArtDCHit*)bpchits->At(i);
	  hid->Fill( hit->GetID() );
	  hlayertdc->Fill( hit->GetLayer(), hit->GetTDC() );
	  pos_sum += hit->GetWirePosition();
	}
	hx->Fill( pos_sum/nhit );// simple position determination
      }

    }

    // clear
    calibbpc->ClearData();
    eventstore->ClearData();
    ++nevent;
  }

  return;
}