StRoot: StEEmcUtil/macros/pedMan.C Source File

00001 // manual pedestal fit to one channel
00002 pedMan ( char *name="out3-5b.hist.root"){
00003 
00004   name="mini1001.hist.root";
00005   TFile *f=new TFile(name);
00006  
00007 
00008   TCanvas *c=new TCanvas("bb","ccc",600,800);
00009     c->Divide(1,2);
00010   int sec=6,isub=3,eta=4;
00011  
00012   char tt1[100];
00013         
00014   sprintf(tt1,"%2.2dT%c%2.2dc%d",sec,'A'+isub,eta,0);
00015   TH1F*h= (TH1F*) f->Get(tt1); // find histrogram in file with this name
00016 
00017   h->Draw(); h->SetAxisRange(0,100); gPad->SetLogy();   
00018   char text[100];  sprintf(text,"eta%2.2d.gif",eta);
00019   getPed(h);
00020   // c->Print(text);
00021 }
00022 
00023 
00024 void getPed(TH1F* h){
00025   
00026   float *x=h->GetArray();
00027 
00028   // find max ADC in first 100 channels
00029 
00030   float ym=0;
00031   int nb=h->GetNbinsX();
00032   int i;
00033   int j=-1;
00034   for(i=1;i<=100;i++){
00035     if(ym>x[i]) continue;
00036     ym=x[i];
00037     j=i;
00038   }
00039 
00040   float x0=h->GetBinCenter(j);
00041   h->Fit("gaus","","",x0-5,x0+4); 
00042 
00043   TF1 *f=h->GetFunction("gaus");
00044   assert(f);
00045   
00046   f->SetLineColor(kRed);
00047   float g=f->GetParameter(1);
00048   float eg=f->GetParError(1);
00049   printf("#%s  mean gain  %f +/- %f \n",h->GetTitle(),g,eg);
00050 }
00051 
00052 
00053 
00054 
00055 
00056 
00057