// *********************************************************************
// To execute this macro under ROOT,
//   1 - launch ROOT (usually type 'root' at your machine's prompt)
//   2 - type '.X plot.C' at the ROOT session prompt
// This macro needs the output ROOT file
// *********************************************************************
{
  gROOT->Reset();
  gStyle->SetPalette(1);
  gROOT->SetStyle("Plain");
  
  TCanvas* c1 = new TCanvas ("c1","",20,20,1000,500);
  
  TFile f("ICSD.root");
  f.ls();
  
  TH1D* hist1 = new TH1D("histo","ICSD", 30, 0.0, 30);
  Double_t ion = 0.0;

  TNtuple* ntuple1 = (TNtuple*)f.Get("ntuple_1");
  ntuple1->SetBranchAddress("ionisations", &ion);
  Int_t nentries = ntuple1->GetEntries();

  for (Int_t i=0; i<nentries; i++)
  {
      ntuple1->GetEntry(i);
      hist1->Fill(ion);
  }

  hist1->Draw();
  hist1->GetXaxis()->SetLabelSize(0.025);
  hist1->GetYaxis()->SetLabelSize(0.025);

  hist1->GetXaxis()->SetTitleSize(0.035);
  hist1->GetYaxis()->SetTitleSize(0.035);

//  hist1->GetXaxis()->SetTittleOffset(1.4);
//  hist1->GetYaxis()->SetTittleOffset(1.4);

  hist1->GetXaxis()->SetTitle("ionisation number");
  hist1->GetYaxis()->SetTitle("frequency");

  c1->SaveAs("ICSD.tiff");
}