void scan(const int arm = 1,
	  const short SELGAP = 4,
	  const int runno = 247385)
{
  char infile[200];
  //  sprintf(infile,"onlmon_minbias.root");
  sprintf(infile,"onlmon_clock.root");

  cout << " infile " << infile << endl;
  
  TFile *f = TFile::Open(infile);

  const char *ARMSTR[2] = {"SOUTH", "NORTH"};
  const char *ORIENTSTR[2] = {"HORIZ", "VERT"};
  const char *ostr[2] = {"H", "V"};

  TH1* h1[5];
  
  char histname[128];
  char info[128];
  int muid_panel = 0;

  for(int iorient=0;iorient<2;iorient++){
    
    for(int ipanel=0;ipanel<6;ipanel++){
      muid_panel = ipanel;
      if (ipanel > 2) { // bottom is sort of reversed in MUID numbering
	muid_panel = 4 - ipanel + 4; // reverse around 4
      }
      
      for(int igap=0;igap<5;igap++) {
	sprintf(histname,"MUI_twopack%d%d%d%d",arm, igap, muid_panel, iorient);
	h1[igap]=(TH1*)gROOT->FindObject(histname);

	cout << " histname " << histname
	     << " Entries " << h1[igap]->GetEntries() << endl;
      }    
    }
  }

}