void laserS2N() {
  gROOT->SetStyle("Plain");

  TCanvas *c1=new TCanvas("c1","Canvas",600,600);
  gStyle->SetOptStat(0);

  TFile::Open("sensor17sn.root");

  hSoverN0->SetTitle(";Laser signal/noise;Number of pixels");

  hSoverN0->SetLineColor(2);
  hSoverN0->SetLineWidth(2);
  hSoverN0->GetYaxis()->SetTitleOffset(1.2);
  //hSoverN0->GetXaxis()->SetRangeUser(-80,119);
  hSoverN0->Draw();

  hSoverN1->SetLineColor(4);
  hSoverN1->SetLineWidth(2);
  hSoverN1->SetLineStyle(2);
  hSoverN1->Draw("same");

  TLatex t;
  t.SetTextSize(0.04);  
  t.SetTextColor(2);
  t.DrawLatex(27,30,"Quadrant 0");
  t.SetTextColor(4);
  t.DrawLatex(27,28,"Quadrant 1");

  c1->Update();
  c1->Print("../laserS2N.png");
}