Noise measurements added and fitted with gaussian function.

gain_measurement.cpp

 double xmin=850.0,xmax = 1750.0,nbins=450.0;
 
-/////////////////////////////////////////////////////////////
-// The function fit_1d sets the cosmetics for the histograms/
-// and fits the histogram with modified erf function.       /
-/////////////////////////////////////////////////////////////
 
-void fit_1d(TH1D* hist_255,int colors,int markers,int amplitude,double fitmin,double fitmax)
+void fit_gaussian_noise(TH1D* hist_255,int colors,int markers,int amplitude,double fitmin,double fitmax)
+{
+  hist_255->SetMarkerColor(colors);
+  hist_255->SetMarkerStyle(markers);
+
+  TF1 *fitgauss = new TF1("fitgauss","([0]*exp(-0.5*((x-[1])/[2])^2))",fitmin,fitmax);
+
+  // cout<<"The fit parameters for the amplitude amp_0"<<amplitude<<""<<" are as follows :"<<std::endl;
+
+  //Setting parameter names
+  fitgauss->SetParNames("constant","mean","noise");
+
+  //Assigning Initial values to the parameters
+
+  fitgauss->SetParameter(0,200.0);
+  int lastbin1 = hist_255->FindLastBinAbove(200);
+  double mean = hist_255->GetBinCenter(lastbin1);
+  //  cout<<"The initial mean value assigned for the data of amp_0 "<<amplitude<<""<<" is "<<""<<mean<<std::endl;
+  fitgauss->SetParameter(1,mean);
+
+  int lastbin2 = hist_255->FindLastBinAbove(150);
+  int lastbin3 = hist_255->FindLastBinAbove(50);
+  int sigma = lastbin3 -lastbin2;
+  // cout<<"The initial noise assigned for the data of amp_0 "<<amplitude<<""<<" is "<<""<<sigma<<std::endl;
+  fitgauss->SetParameter(2,sigma);
+
+  fitgauss->SetLineWidth(2);
+  fitgauss->SetLineColor(2);
+
+  hist_255->Fit("fitgauss"," R");
+  hist_255->GetListOfFunctions()->FindObject("fitgauss")->Draw("same");
+  hist_255->SetStats(0);
+}
+
+void fit_modified_erf(TH1D* hist_255,int colors,int markers,int amplitude,double fitmin,double fitmax)
 {
   // hist_255->GetXaxis()->SetTitle("Threshold");
   // hist_255->GetYaxis()->SetTitle("# signals above the threshold");
@@ -13,47 +43,43 @@ void fit_1d(TH1D* hist_255,int colors,int markers,int amplitude,double fitmin,do
   hist_255->SetMarkerStyle(markers);
 
 
-  TF1 *fitfunc = new TF1("fitfunc","([0]/2)*(1-TMath::Erf((x-[1])/(sqrt(2)*[2])))",fitmin,fitmax);
+  TF1 *fiterf = new TF1("fiterf","([0]/2)*(1-TMath::Erf((x-[1])/(sqrt(2)*[2])))",fitmin,fitmax);
 
-  cout<<"The fit parameters for the amplitude amp_0"<<amplitude<<""<<" are as follows :"<<std::endl;
+  // cout<<"The fit parameters for the amplitude amp_0"<<amplitude<<""<<" are as follows :"<<std::endl;
 
   /*Setting parameter names*/
-  fitfunc->SetParNames("constant","mean","noise");
+  fiterf->SetParNames("constant","mean","noise");
 
 
   //Assigning Initial values to the parameters
 
-  fitfunc->SetParameter(0,200.0);
+  fiterf->SetParameter(0,200.0);
   int lastbin1 = hist_255->FindLastBinAbove(200);
   double mean = hist_255->GetBinCenter(lastbin1);
   //  cout<<"The initial mean value assigned for the data of amp_0 "<<amplitude<<""<<" is "<<""<<mean<<std::endl;
-  fitfunc->SetParameter(1,mean);
+  fiterf->SetParameter(1,mean);
 
   int lastbin2 = hist_255->FindLastBinAbove(150);
   int lastbin3 = hist_255->FindLastBinAbove(50);
   int sigma = lastbin3 -lastbin2;
   // cout<<"The initial noise assigned for the data of amp_0 "<<amplitude<<""<<" is "<<""<<sigma<<std::endl;
-  fitfunc->SetParameter(2,sigma);
+  fiterf->SetParameter(2,sigma);
 
-  fitfunc->SetLineWidth(2);
-  fitfunc->SetLineColor(2);
+  fiterf->SetLineWidth(2);
+  fiterf->SetLineColor(2);
 
-  hist_255->Fit("fitfunc"," R");
-  hist_255->GetListOfFunctions()->FindObject("fitfunc")->Draw("same");
+  hist_255->Fit("fiterf"," R");
+  hist_255->GetListOfFunctions()->FindObject("fiterf")->Draw("same");
   hist_255->SetStats(0);
 
 }
 
-
-
 std::vector<TH1D*> gain_measurement_pixel(int i, int j)
 {
-  //double xmin=850.0,xmax = 1750.0;
-
-  std::vector<int>colors={kAzure,kTeal+3,kViolet+3};
-  std::vector<int>markers={1,1,1};
-  std::vector<double>fitmin ={1220.,1200.,1150.};
-  std::vector<double>fitmax={1700.,1420.,1240.};
+  std::vector<int>colors={kAzure,kTeal+3,kViolet+3,kOrange+4};
+  std::vector<int>markers={1,1,1,1};
+  std::vector<double>fitmin ={1220.,1200.,1150.,1000.0};
+  std::vector<double>fitmax={1700.,1420.,1240.,1500.0};
   std::vector<TH1D*> hist_255;
 
   //The data files are named as following : 000_000.dat to 256_256.dat
@@ -65,11 +91,12 @@ std::vector<TH1D*> gain_measurement_pixel(int i, int j)
   std::vector<std::string> filenames = {
     std::string("amp03/" + sfilename.str()),
     std::string("amp02/" + sfilename.str()),
-    std::string("amp01/" + sfilename.str())
+    std::string("amp01/" + sfilename.str()),
+    std::string("amp00/" + sfilename.str())
   };
 
 
-  for(int amp = 0; amp < 3; amp++) {
+  for(int amp = 0; amp < 4; amp++) {
 
     std::ifstream amplitude_file(filenames.at(amp).c_str());
     if(amplitude_file.is_open()) {
@@ -95,7 +122,12 @@ std::vector<TH1D*> gain_measurement_pixel(int i, int j)
     } else {
       cout << "Error opening file. Exit." <<std::endl;
     }
-    fit_1d(hist_255.at(amp),colors.at(amp),markers.at(amp),amp,fitmin.at(amp),fitmax.at(amp));
+    if(filenames.at(amp)==0||filenames.at(amp)==1||filenames.at(amp)==2){
+      fit_modified_erf(hist_255.at(amp),colors.at(amp),markers.at(amp),amp,fitmin.at(amp),fitmax.at(amp));
+    }
+    else{
+      fit_gaussian_noise(hist_255.at(amp),colors.at(amp),markers.at(amp),amp,fitmin.at(amp),fitmax.at(amp));
+    }
   }
   return hist_255;
 }
@@ -148,6 +180,11 @@ void gain_measurement()
   if(pixel_histograms.at(2)){
     leg->AddEntry(pixel_histograms.at(2),"low amplitude","p");
   }
+
+  if(pixel_histograms.at(3)){
+    leg->AddEntry(pixel_histograms.at(3),"noise","p");
+  }
+
   leg->Draw("SAME");
 
 }