{
  gROOT->SetStyle("Plain");
  Double_t E0 = 1400; //keV
  Double_t c = 3e8;
  Double_t beta = 0.065;
  Double_t v = c*beta;
  Double_t d=10; //cm
  Double_t DE;
  Double_t Dv = 0;
  TCanvas *c1 = new TCanvas("c1","",600,500);
  leg=new TLegend(0.6,0.1,0.9,0.5);
  TGraph *dopp[9];
  char doppname[20];
  Double_t x;
  for(Int_t i=0;i<7;i++){
    sprintf(doppname,"dopp%d",(i+1));
    dopp[i+1] = new TGraph(180);
    dopp[i+1]->SetName(doppname);
    dopp[i+1]->SetTitle();
    if(i==0)x=0.2;
    else x=i;
    Double_t Dthetarad = TMath::ATan((x/2)/d); //half opening angle
    Double_t Dthetadeg = TMath::RadToDeg()*Dthetarad;
    Int_t thetadeg;
    for(thetadeg=0;thetadeg<360;thetadeg++){
      Double_t thetarad=TMath::DegToRad()*thetadeg;
      DE = E0 * TMath::Cos(thetarad) * (Dv/c) - E0 * (v/c) * TMath::Sin(thetarad) * Dthetarad;
      dopp[i+1]->SetPoint((thetadeg+1),thetadeg,DE);
  }
    if (i==0)dopp[i+1]->Draw("al");
    else dopp[i+1]->Draw("l");
    dopp[i+1]->GetXaxis()->Set(360,0,360);
    dopp[i+1]->GetXaxis()->SetTitle("#theta (degrees)");
    dopp[i+1]->GetYaxis()->SetTitle("Doppler Broadening (keV)");
    dopp[i+1]->SetMaximum(30);
    dopp[i+1]->SetMinimum(-30);
    dopp[i+1]->SetLineStyle(i+1);
    dopp[i+1]->SetLineWidth(2);
    if ((i+1)==5)    dopp[i+1]->SetLineColor(9);
    else dopp[i+1]->SetLineColor(i+1);
    char legent[50];
    sprintf(legent,"#Delta#theta = %4.2f#circ, x = %3.1fcm",Dthetadeg,x);
    leg->AddEntry(dopp[i+1],legent,"L");
  }
  leg->SetFillColor(kWhite);
  leg->Draw();
  c1->Print("dopp_test.eps");
}