ITS/AliITSdEdxAnalyzer.cxx

   1 /**************************************************************************
   2  * Copyright(c) 2007-2009, ALICE Experiment at CERN, All rights reserved. *
   3  *                                                                        *
   4  * Author: The ALICE Off-line Project.                                    *
   5  * Contributors are mentioned in the code where appropriate.              *
   6  *                                                                        *
   7  * Permission to use, copy, modify and distribute this software and its   *
   8  * documentation strictly for non-commercial purposes is hereby granted   *
   9  * without fee, provided that the above copyright notice appears in all   *
  10  * copies and that both the copyright notice and this permission notice   *
  11  * appear in the supporting documentation. The authors make no claims     *
  12  * about the suitability of this software for any purpose. It is          *
  13  * provided "as is" without express or implied warranty.                  *
  14  **************************************************************************/
  15
  16 /* $Id$ */
  17
  18 ///////////////////////////////////////////////////////////////////
  19 //                                                               //
  20 // Implementation of the base class for dEdx analysis            //
  21 // Origin: F.Prino, Torino, prino@to.infn.it                     //
  22 //                                                               //
  23 ///////////////////////////////////////////////////////////////////
  24
  25 #include <TString.h>
  26 #include <TFile.h>
  27 #include <TParticlePDG.h>
  28 #include <TDatabasePDG.h>
  29 #include "AliITSdEdxAnalyzer.h"
  30 #include "AliExternalTrackParam.h"
  31 #include "AliITSpidESD.h"
  32 #include "AliPID.h"
  33
  34 ClassImp(AliITSdEdxAnalyzer)
  35
  36 const Int_t AliITSdEdxAnalyzer::fgkPdgCode[kNParticles]={211,321,2212};
  37 const Int_t AliITSdEdxAnalyzer::fgkLayerCode[kNValuesdEdx]={3,4,5,6,0};
  38
  39 //______________________________________________________________________
  40 AliITSdEdxAnalyzer::AliITSdEdxAnalyzer() :
  41   TObject(),
  42   fNPBins(10),
  43   fPMin(0.1),
  44   fPMax(1.1),
  45   fHistodEdx(0),
  46   fHistoDeltadEdx(0),
  47   fHistodEdxVsP(0),
  48   fThickness(0.03),
  49   fDensity(2.33),
  50   fBBmodel(0),
  51   fMIP(82.),
  52   fTPCpidCut(0.5)
  53 {
  54   // default constructor
  55   BookHistos();
  56 }
  57 //______________________________________________________________________
  58 AliITSdEdxAnalyzer::AliITSdEdxAnalyzer(const Int_t npbins, const Float_t pmin, const Float_t pmax) :
  59   TObject(),
  60   fNPBins(npbins),
  61   fPMin(pmin),
  62   fPMax(pmax),
  63   fHistodEdx(0),
  64   fHistoDeltadEdx(0),
  65   fHistodEdxVsP(0),
  66   fThickness(0.03),
  67   fDensity(2.33),
  68   fBBmodel(0),
  69   fMIP(82.),
  70   fTPCpidCut(0.5)
  71 {
  72   // standard constructor
  73   BookHistos();
  74 }
  75 //______________________________________________________________________
  76 AliITSdEdxAnalyzer::~AliITSdEdxAnalyzer(){
  77   // destructor
  78   DeleteHistos();
  79 }
  80 //______________________________________________________________________
  81 void AliITSdEdxAnalyzer::SetMomentumBins(const Int_t npbins, const Float_t pmin, const Float_t pmax){
  82   // Kill exisiting histos, set new binning, book new histos
  83   DeleteHistos();
  84   fNPBins=npbins;
  85   fPMin=pmin;
  86   fPMax=pmax;
  87   BookHistos();
  88 }
  89 //______________________________________________________________________
  90 void AliITSdEdxAnalyzer::DeleteHistos(){
  91   //
  92   if(fHistodEdx){
  93     for(Int_t i=0; i<GetNHistos();i++) delete fHistodEdx[i];
  94     delete [] fHistodEdx;
  95     fHistodEdx=0;
  96   }
  97   if(fHistoDeltadEdx){
  98     for(Int_t i=0; i<GetNHistos();i++) delete fHistoDeltadEdx[i];
  99     delete [] fHistoDeltadEdx;
 100     fHistoDeltadEdx=0;
 101   }
 102   if(fHistodEdxVsP){
 103     for(Int_t i=0; i<GetNHistos2();i++) delete fHistodEdxVsP[i];
 104     delete [] fHistodEdxVsP;
 105     fHistodEdxVsP=0;
 106   }
 107 }
 108 //______________________________________________________________________
 109 void AliITSdEdxAnalyzer::BookHistos(){
 110   //
 111   fHistodEdx=new TH1F*[GetNHistos()];
 112   fHistoDeltadEdx=new TH1F*[GetNHistos()];
 113   for(Int_t iSpecie=0; iSpecie<kNParticles; iSpecie++){
 114     for(Int_t iPBin=0; iPBin<fNPBins; iPBin++){
 115       for(Int_t iVal=0; iVal<kNValuesdEdx; iVal++){
 116         TString hisnam1=Form("hdEdx%dpbin%dpart%d",fgkLayerCode[iVal],iPBin,fgkPdgCode[iSpecie]);
 117         TString histit1=Form("dEdx layer %d (keV) pbin%d part%d",fgkLayerCode[iVal],iPBin,fgkPdgCode[iSpecie]);
 118         if(iVal==kNValuesdEdx-1) histit1=Form("dEdx trunc. mean (keV) pbin%d part%d",iPBin,fgkPdgCode[iSpecie]);
 119         fHistodEdx[GetIndex(iSpecie,iPBin,iVal)]=new TH1F(hisnam1.Data(),histit1.Data(),100,0.,500.);
 120         fHistodEdx[GetIndex(iSpecie,iPBin,iVal)]->GetXaxis()->SetTitle(histit1.Data());
 121         TString hisnam2=Form("hdeltadEdx%dpbin%dpart%d",fgkLayerCode[iVal],iPBin,fgkPdgCode[iSpecie]);
 122         TString histit2=Form("(dEdx_l%d-BetheBloch)/BetheBloch pbin%d part%d",fgkLayerCode[iVal],iPBin,fgkPdgCode[iSpecie]);
 123         if(iVal==kNValuesdEdx-1) histit1=Form("(dEdx_truncmean-BetheBloch)/BetheBloch pbin%d part%d",iPBin,fgkPdgCode[iSpecie]);
 124         fHistoDeltadEdx[GetIndex(iSpecie,iPBin,iVal)]=new TH1F(hisnam2.Data(),histit2.Data(),100,-0.5,0.5);
 125         fHistoDeltadEdx[GetIndex(iSpecie,iPBin,iVal)]->GetXaxis()->SetTitle(histit2.Data());
 126       }
 127     }
 128   }
 129
 130   fHistodEdxVsP=new TH2F*[GetNHistos2()];
 131   for(Int_t iSpecie=0; iSpecie<kNParticles; iSpecie++){
 132     for(Int_t iVal=0; iVal<kNValuesdEdx; iVal++){
 133       TString hisnam=Form("hdEdx%dVsPpart%d",fgkLayerCode[iVal],fgkPdgCode[iSpecie]);
 134       TString histit=Form("dEdx layer %d (keV) vs P part%d",fgkLayerCode[iVal],fgkPdgCode[iSpecie]);
 135       if(iVal==kNValuesdEdx-1) histit=Form("dEdx trunc. mean (keV) vs P part%d",fgkPdgCode[iSpecie]);
 136       fHistodEdxVsP[GetIndex2(iSpecie,iVal)]=new TH2F(hisnam.Data(),histit.Data(),50,fPMin,fPMax,50,0.,500.);
 137       histit.ReplaceAll(" vs P "," ");
 138       fHistodEdxVsP[GetIndex2(iSpecie,iVal)]->GetYaxis()->SetTitle(histit.Data());
 139       fHistodEdxVsP[GetIndex2(iSpecie,iVal)]->GetXaxis()->SetTitle("Momentum (GeV/c)");
 140     }
 141   }
 142 }
 143 //______________________________________________________________________
 144 void AliITSdEdxAnalyzer:: WriteHistos(TString filename) const {
 145   TFile *outfile=new TFile(filename.Data(),"recreate");
 146   outfile->cd();
 147   for(Int_t i=0; i<GetNHistos();i++){
 148     fHistodEdx[i]->Write();
 149     fHistoDeltadEdx[i]->Write();
 150   }
 151   for(Int_t i=0; i<GetNHistos2();i++) fHistodEdxVsP[i]->Write();
 152   outfile->Close();
 153   delete outfile;
 154 }
 155 //______________________________________________________________________
 156 void AliITSdEdxAnalyzer::ReadEvent(AliESDEvent* esd, AliStack* stack){
 157   // Fill histos
 158   // if stack is !=0 MC truth is used to define particle specie
 159   // else TPC pid is used to define particle specie
 160
 161   if(!esd) AliFatal("Bad ESD event");
 162   for (Int_t iTrack = 0; iTrack < esd->GetNumberOfTracks(); iTrack++) {
 163     AliESDtrack* track = esd->GetTrack(iTrack);
 164     Double_t trmean=track->GetITSsignal();
 165     Double_t sig[4];
 166     track->GetITSdEdxSamples(sig);
 167     Double_t preco=track->P();
 168     Int_t iPBin=GetMomentumBin(preco);
 169     if(iPBin==-1) continue;
 170     Int_t iSpecie=-1;
 171     Double_t dedxbb=0;
 172     if(stack){
 173       Int_t lab=track->GetLabel();
 174       if(lab<0) continue;
 175       TParticle* part=(TParticle*)stack->Particle(lab);
 176       Int_t absPdgCode=TMath::Abs(part->GetPdgCode());
 177       iSpecie=GetSpecieBin(absPdgCode);
 178       if(iSpecie==-1) continue;
 179       dedxbb=BetheBloch(part);
 180     }else{
 181       iSpecie=GetPaticleIdFromTPC(track);
 182       if(iSpecie==-1) continue;
 183       TParticlePDG* p=TDatabasePDG::Instance()->GetParticle(fgkPdgCode[iSpecie]);
 184       dedxbb=BetheBloch(preco,p->Mass());
 185     }
 186     for(Int_t ilay=0;ilay<4;ilay++){
 187       if(sig[ilay]>0.){
 188         fHistodEdx[GetIndex(iSpecie,iPBin,ilay)]->Fill(sig[ilay]);
 189         fHistoDeltadEdx[GetIndex(iSpecie,iPBin,ilay)]->Fill((sig[ilay]-dedxbb)/dedxbb);
 190         fHistodEdxVsP[GetIndex2(iSpecie,ilay)]->Fill(preco,sig[ilay]);
 191       }
 192     }
 193     if(trmean>0.){
 194       fHistodEdx[GetIndex(iSpecie,iPBin,4)]->Fill(trmean);
 195       fHistoDeltadEdx[GetIndex(iSpecie,iPBin,4)]->Fill((trmean-dedxbb)/dedxbb);
 196       fHistodEdxVsP[GetIndex2(iSpecie,4)]->Fill(preco,trmean);
 197     }
 198   }
 199 }
 200 //______________________________________________________________________
 201 Int_t AliITSdEdxAnalyzer::GetPaticleIdFromTPC(const AliESDtrack* track) const {
 202   //
 203   Double_t tpcpid[AliPID::kSPECIES];
 204   track->GetTPCpid(tpcpid);
 205   Int_t maxPos=-1;
 206   Float_t maxProb=0.;
 207   for(Int_t is=0; is<AliPID::kSPECIES; is++){
 208     if(tpcpid[is]>maxProb){
 209       maxProb=tpcpid[is];
 210       maxPos=is;
 211     }
 212   }
 213   Int_t iSpecie=-1;
 214   if(maxProb>fTPCpidCut){
 215     if(maxPos==AliPID::kPion) iSpecie=0;
 216     else if(maxPos==AliPID::kKaon) iSpecie=1;
 217     else if(maxPos==AliPID::kProton) iSpecie=2;
 218   }
 219   return iSpecie;
 220 }
 221 //______________________________________________________________________
 222 Double_t AliITSdEdxAnalyzer::BetheBloch(const Float_t p, const Float_t m) const {
 223   //
 224   Double_t dedxbb=0.;
 225   switch(fBBmodel){
 226   case 0:
 227     Double_t betagamma=p/m;
 228     Double_t conv=fDensity*1E6*fThickness/116.31*fMIP;
 229     dedxbb=conv*AliExternalTrackParam::BetheBlochSolid(betagamma);
 230     break;
 231   case 1:
 232     dedxbb=fMIP*AliITSpidESD::Bethe(p,m);
 233     break;
 234   }
 235   return dedxbb;
 236 }
 237 //______________________________________________________________________
 238 TGraph* AliITSdEdxAnalyzer::GetBetheBlochGraph(const Int_t pdgcode) const {
 239   // Fills a TGraph with Bethe-Bloch expe
 240   TGraph* g=new TGraph(0);
 241   TParticlePDG* p=TDatabasePDG::Instance()->GetParticle(pdgcode);
 242   Float_t mass=p->Mass();
 243   for(Int_t ip=0; ip<100;ip++){
 244     Float_t p=fPMin+(ip+0.5)*(fPMax-fPMin)/100.;
 245     g->SetPoint(ip,p,BetheBloch(p,mass));
 246   }
 247   g->GetXaxis()->SetTitle("Momentum (GeV/c)");
 248   g->GetYaxis()->SetTitle("dE/dx (keV/300 #mum)");
 249   return g;
 250 }