void tgraph_array(){
  double x[] = {18.722, 19, 19.5, 20, 20.5, 21, 21.5, 22 , 23, 23.5, 24, 24.5, 25, 25.5, 26, 26.5, 27, 27.5, 28, 28.5, 29, 29.5, 30, 32.5, 35, 37.5, 40, 45, 47.5, 50, 52.5, 55, 57.5, 60, 62.5, 65, 72.5, 75, 77.5, 80, 85, 87.5, 90, 100, 102.5, 105, 107.5, 110, 112.5, 115, 117.5, 120, 122.5, 125, 127.5, 130, 132.5, 135, 137.5, 140, 142.5, 145, 147.5, 150.};
  double y[] = {0.0, 0.000093273, 0.000354167, 0.0006875, 0.00137322, 0.00278194, 0.00496428, 0.00567111, 0.00650744, 0.00676991, 0.00562713, 0.00297917, 0.00366927, 0.004125, 0.003355, 0.00271212, 0.00231861, 0.00235417, 0.0020875, 0.00176833, 0.00163426, 0.00165357, 0.00157744, 0.00127633, 0.00104167, 0.000895011, 0.000775807, 0.000566122, 0.000458931, 0.000357328, 0.000294003, 0.000251503, 0.000199038, 0.000149, 0.00011862, 0.000105919, 0.0000712972, 0.0000599773,  0.0000507858, 0.000045, 0.0000362928, 0.0000315124, 0.0000275856, 0.000017, 0.0000146941, 0.0000129529, 0.0000116025, 0.0000104687, 0.00000941879, 0.00000846238, 0.00000763881, 0.00000698742, 0.00000643988, 0.00000592057, 0.00000545785, 0.0000050801, 0.00000475711, 0.00000444586, 0.00000415553, 0.00000389529, 0.00000365601, 0.00000342634, 0.00000321208, 0.00000301905};

   TGraph* gr =new TGraph(64,x,y);

   gr->Draw("AL*");
   gr->SetTitle(";Energy [MeV];Cross Section [barns]");

   int nb = 500;
   double x1=18. , x2=152.;
   double dx = (x2-x1)/nb;
   cout << "dx = " << dx << endl;
   auto h = new TH1D("h","h",nb,x1,x2);

   for (int b=0; b<=nb; b++) {
      h->SetBinContent(b,gr->Eval(x1+b*dx-0.1222));
      //h->SetBinContent(b, 1.463E11*gr->Eval(x1+b*dx-0.1222));
   }



   h->Draw("same hist");


}