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 "AliITSPIDResponse.h"
  33 #include "AliPID.h"
  34
  35 ClassImp(AliITSdEdxAnalyzer)
  36
  37 const Int_t AliITSdEdxAnalyzer::fgkPdgCode[kNParticles]={211,321,2212};
  38 const Int_t AliITSdEdxAnalyzer::fgkLayerCode[kNValuesdEdx]={3,4,5,6,0};
  39
  40 //______________________________________________________________________
  41 AliITSdEdxAnalyzer::AliITSdEdxAnalyzer() :
  42   TObject(),
  43   fNPBins(10),
  44   fPMin(0.1),
  45   fPMax(1.1),
  46   fHistodEdx(0),
  47   fHistoDeltadEdx(0),
  48   fHistodEdxVsP(0),
  49   fThickness(0.03),
  50   fDensity(2.33),
  51   fBBmodel(0),
  52   fMIP(82.),
  53   fTPCpidCut(0.5)
  54 {
  55   // default constructor
  56   BookHistos();
  57 }
  58 //______________________________________________________________________
  59 AliITSdEdxAnalyzer::AliITSdEdxAnalyzer(const Int_t npbins, const Float_t pmin, const Float_t pmax) :
  60   TObject(),
  61   fNPBins(npbins),
  62   fPMin(pmin),
  63   fPMax(pmax),
  64   fHistodEdx(0),
  65   fHistoDeltadEdx(0),
  66   fHistodEdxVsP(0),
  67   fThickness(0.03),
  68   fDensity(2.33),
  69   fBBmodel(0),
  70   fMIP(82.),
  71   fTPCpidCut(0.5)
  72 {
  73   // standard constructor
  74   BookHistos();
  75 }
  76 //______________________________________________________________________
  77 AliITSdEdxAnalyzer::~AliITSdEdxAnalyzer(){
  78   // destructor
  79   DeleteHistos();
  80 }
  81 //______________________________________________________________________
  82 void AliITSdEdxAnalyzer::SetMomentumBins(const Int_t npbins, const Float_t pmin, const Float_t pmax){
  83   // Kill exisiting histos, set new binning, book new histos
  84   DeleteHistos();
  85   fNPBins=npbins;
  86   fPMin=pmin;
  87   fPMax=pmax;
  88   BookHistos();
  89 }
  90 //______________________________________________________________________
  91 void AliITSdEdxAnalyzer::DeleteHistos(){
  92   //
  93   if(fHistodEdx){
  94     for(Int_t i=0; i<GetNHistos();i++) delete fHistodEdx[i];
  95     delete [] fHistodEdx;
  96     fHistodEdx=0;
  97   }
  98   if(fHistoDeltadEdx){
  99     for(Int_t i=0; i<GetNHistos();i++) delete fHistoDeltadEdx[i];
 100     delete [] fHistoDeltadEdx;
 101     fHistoDeltadEdx=0;
 102   }
 103   if(fHistodEdxVsP){
 104     for(Int_t i=0; i<GetNHistos2();i++) delete fHistodEdxVsP[i];
 105     delete [] fHistodEdxVsP;
 106     fHistodEdxVsP=0;
 107   }
 108 }
 109 //______________________________________________________________________
 110 void AliITSdEdxAnalyzer::BookHistos(){
 111   //
 112   fHistodEdx=new TH1F*[GetNHistos()];
 113   fHistoDeltadEdx=new TH1F*[GetNHistos()];
 114   for(Int_t iSpecie=0; iSpecie<kNParticles; iSpecie++){
 115     for(Int_t iPBin=0; iPBin<fNPBins; iPBin++){
 116       for(Int_t iVal=0; iVal<kNValuesdEdx; iVal++){
 117         TString hisnam1=Form("hdEdx%dpbin%dpart%d",fgkLayerCode[iVal],iPBin,fgkPdgCode[iSpecie]);
 118         TString histit1=Form("dEdx layer %d (keV) pbin%d part%d",fgkLayerCode[iVal],iPBin,fgkPdgCode[iSpecie]);
 119         if(iVal==kNValuesdEdx-1) histit1=Form("dEdx trunc. mean (keV) pbin%d part%d",iPBin,fgkPdgCode[iSpecie]);
 120         fHistodEdx[GetIndex(iSpecie,iPBin,iVal)]=new TH1F(hisnam1.Data(),histit1.Data(),100,0.,500.);
 121         fHistodEdx[GetIndex(iSpecie,iPBin,iVal)]->GetXaxis()->SetTitle(histit1.Data());
 122         TString hisnam2=Form("hdeltadEdx%dpbin%dpart%d",fgkLayerCode[iVal],iPBin,fgkPdgCode[iSpecie]);
 123         TString histit2=Form("(dEdx_l%d-BetheBloch)/BetheBloch pbin%d part%d",fgkLayerCode[iVal],iPBin,fgkPdgCode[iSpecie]);
 124         if(iVal==kNValuesdEdx-1) histit1=Form("(dEdx_truncmean-BetheBloch)/BetheBloch pbin%d part%d",iPBin,fgkPdgCode[iSpecie]);
 125         fHistoDeltadEdx[GetIndex(iSpecie,iPBin,iVal)]=new TH1F(hisnam2.Data(),histit2.Data(),100,-0.5,0.5);
 126         fHistoDeltadEdx[GetIndex(iSpecie,iPBin,iVal)]->GetXaxis()->SetTitle(histit2.Data());
 127       }
 128     }
 129   }
 130
 131   fHistodEdxVsP=new TH2F*[GetNHistos2()];
 132   for(Int_t iSpecie=0; iSpecie<kNParticles; iSpecie++){
 133     for(Int_t iVal=0; iVal<kNValuesdEdx; iVal++){
 134       TString hisnam=Form("hdEdx%dVsPpart%d",fgkLayerCode[iVal],fgkPdgCode[iSpecie]);
 135       TString histit=Form("dEdx layer %d (keV) vs P part%d",fgkLayerCode[iVal],fgkPdgCode[iSpecie]);
 136       if(iVal==kNValuesdEdx-1) histit=Form("dEdx trunc. mean (keV) vs P part%d",fgkPdgCode[iSpecie]);
 137       fHistodEdxVsP[GetIndex2(iSpecie,iVal)]=new TH2F(hisnam.Data(),histit.Data(),50,fPMin,fPMax,50,0.,500.);
 138       histit.ReplaceAll(" vs P "," ");
 139       fHistodEdxVsP[GetIndex2(iSpecie,iVal)]->GetYaxis()->SetTitle(histit.Data());
 140       fHistodEdxVsP[GetIndex2(iSpecie,iVal)]->GetXaxis()->SetTitle("Momentum (GeV/c)");
 141     }
 142   }
 143 }
 144 //______________________________________________________________________
 145 void AliITSdEdxAnalyzer:: WriteHistos(TString filename) const {
 146   TFile *outfile=new TFile(filename.Data(),"recreate");
 147   outfile->cd();
 148   for(Int_t i=0; i<GetNHistos();i++){
 149     fHistodEdx[i]->Write();
 150     fHistoDeltadEdx[i]->Write();
 151   }
 152   for(Int_t i=0; i<GetNHistos2();i++) fHistodEdxVsP[i]->Write();
 153   outfile->Close();
 154   delete outfile;
 155 }
 156 //______________________________________________________________________
 157 void AliITSdEdxAnalyzer::ReadEvent(AliESDEvent* esd, AliStack* stack){
 158   // Fill histos
 159   // if stack is !=0 MC truth is used to define particle specie
 160   // else TPC pid is used to define particle specie
 161
 162   if(!esd) AliFatal("Bad ESD event");
 163   for (Int_t iTrack = 0; iTrack < esd->GetNumberOfTracks(); iTrack++) {
 164     AliESDtrack* track = esd->GetTrack(iTrack);
 165     Double_t trmean=track->GetITSsignal();
 166     Double_t sig[4];
 167     track->GetITSdEdxSamples(sig);
 168     Double_t preco=track->P();
 169     Int_t iPBin=GetMomentumBin(preco);
 170     if(iPBin==-1) continue;
 171     Int_t iSpecie=-1;
 172     Double_t dedxbb=0;
 173     if(stack){
 174       Int_t lab=track->GetLabel();
 175       if(lab<0) continue;
 176       TParticle* part=(TParticle*)stack->Particle(lab);
 177       Int_t absPdgCode=TMath::Abs(part->GetPdgCode());
 178       iSpecie=GetSpecieBin(absPdgCode);
 179       if(iSpecie==-1) continue;
 180       dedxbb=BetheBloch(part);
 181     }else{
 182       iSpecie=GetPaticleIdFromTPC(track);
 183       if(iSpecie==-1) continue;
 184       TParticlePDG* p=TDatabasePDG::Instance()->GetParticle(fgkPdgCode[iSpecie]);
 185       dedxbb=BetheBloch(preco,p->Mass());
 186     }
 187     for(Int_t ilay=0;ilay<4;ilay++){
 188       if(sig[ilay]>0.){
 189         fHistodEdx[GetIndex(iSpecie,iPBin,ilay)]->Fill(sig[ilay]);
 190         fHistoDeltadEdx[GetIndex(iSpecie,iPBin,ilay)]->Fill((sig[ilay]-dedxbb)/dedxbb);
 191         fHistodEdxVsP[GetIndex2(iSpecie,ilay)]->Fill(preco,sig[ilay]);
 192       }
 193     }
 194     if(trmean>0.){
 195       fHistodEdx[GetIndex(iSpecie,iPBin,4)]->Fill(trmean);
 196       fHistoDeltadEdx[GetIndex(iSpecie,iPBin,4)]->Fill((trmean-dedxbb)/dedxbb);
 197       fHistodEdxVsP[GetIndex2(iSpecie,4)]->Fill(preco,trmean);
 198     }
 199   }
 200 }
 201 //______________________________________________________________________
 202 Int_t AliITSdEdxAnalyzer::GetPaticleIdFromTPC(const AliESDtrack* track) const {
 203   //
 204   Double_t tpcpid[AliPID::kSPECIES];
 205   track->GetTPCpid(tpcpid);
 206   Int_t maxPos=-1;
 207   Float_t maxProb=0.;
 208   for(Int_t is=0; is<AliPID::kSPECIES; is++){
 209     if(tpcpid[is]>maxProb){
 210       maxProb=tpcpid[is];
 211       maxPos=is;
 212     }
 213   }
 214   Int_t iSpecie=-1;
 215   if(maxProb>fTPCpidCut){
 216     if(maxPos==AliPID::kPion) iSpecie=0;
 217     else if(maxPos==AliPID::kKaon) iSpecie=1;
 218     else if(maxPos==AliPID::kProton) iSpecie=2;
 219   }
 220   return iSpecie;
 221 }
 222 //______________________________________________________________________
 223 Double_t AliITSdEdxAnalyzer::BetheBloch(const Float_t p, const Float_t m) const {
 224   //
 225   static AliITSPIDResponse pidResponse;
 226   Double_t dedxbb=0.;
 227   if(fBBmodel==0){
 228     Double_t betagamma=p/m;
 229     Double_t conv=fDensity*1E6*fThickness/116.24*fMIP;
 230     dedxbb=conv*AliExternalTrackParam::BetheBlochSolid(betagamma);
 231   }else if(fBBmodel==1){
 232     dedxbb=pidResponse.Bethe(p,m);
 233   }
 234   return dedxbb;
 235 }
 236 //______________________________________________________________________
 237 TGraph* AliITSdEdxAnalyzer::GetBetheBlochGraph(const Int_t pdgcode) const {
 238  // Fills a TGraph with Bethe-Bloch expe
 239  TGraph* g=new TGraph(0);
 240  TParticlePDG* part=TDatabasePDG::Instance()->GetParticle(pdgcode);
 241  Float_t mass=part->Mass();
 242  for(Int_t ip=0; ip<100;ip++){
 243    Float_t p=fPMin+(ip+0.5)*(fPMax-fPMin)/100.;
 244    g->SetPoint(ip,p,BetheBloch(p,mass));
 245  }
 246  g->GetXaxis()->SetTitle("Momentum (GeV/c)");
 247  g->GetYaxis()->SetTitle("dE/dx (keV/300 #mum)");
 248  return g;
 249 }