RICH/AliRICHv1.cxx

   1 // **************************************************************************
   2 // * Copyright(c) 1998-1999, 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
  17 #include "AliRICHv1.h"
  18 #include "AliRICHParam.h"
  19 #include "AliRICHChamber.h"
  20 #include <TParticle.h>
  21 #include <TRandom.h>
  22 #include <TVirtualMC.h>
  23 #include <TPDGCode.h>
  24
  25 #include <AliConst.h>
  26 #include <AliPDG.h>
  27 #include <AliRun.h>
  28 #include <AliMC.h>
  29
  30 ClassImp(AliRICHv1)
  31 //__________________________________________________________________________________________________
  32 void AliRICHv1::StepManager()
  33 {
  34 //Full Step Manager
  35
  36   Int_t          copy;
  37   static Int_t   iCurrentChamber;
  38
  39 //Treat photons
  40   static TLorentzVector cerX4;
  41   if((gMC->TrackPid()==kCerenkov||gMC->TrackPid()==kFeedback)&&gMC->CurrentVolID(copy)==gMC->VolId("CSI ")){//photon in CSI
  42     if(gMC->Edep()>0.){//CF+CSI+DE
  43       if(IsLostByFresnel()){ gMC->StopTrack(); return;}
  44       gMC->TrackPosition(cerX4); gMC->CurrentVolOffID(2,iCurrentChamber);
  45
  46       AddHit(iCurrentChamber,gAlice->GetMCApp()->GetCurrentTrackNumber(),cerX4.Vect(),cerX4.Vect());//HIT for PHOTON in conditions CF+CSI+DE
  47       GenerateFeedbacks(iCurrentChamber);
  48     }//CF+CSI+DE
  49   }//CF in CSI
  50
  51 //Treat charged particles
  52   static Float_t eloss;
  53   static TLorentzVector mipInX4,mipOutX4;
  54   if(gMC->TrackCharge() && gMC->CurrentVolID(copy)==gMC->VolId("GAP ")){//MIP in GAP
  55     gMC->CurrentVolOffID(3,iCurrentChamber);
  56     if(gMC->IsTrackEntering()||gMC->IsNewTrack()) {//MIP in GAP entering or newly created
  57       eloss=0;
  58       gMC->TrackPosition(mipInX4);
  59     }else if(gMC->IsTrackExiting()||gMC->IsTrackStop()||gMC->IsTrackDisappeared()){//MIP in GAP exiting or disappeared
  60       eloss+=gMC->Edep();//take into account last step dEdX
  61       gMC->TrackPosition(mipOutX4);
  62       AddHit(iCurrentChamber,gAlice->GetMCApp()->GetCurrentTrackNumber(),mipInX4.Vect(),mipOutX4.Vect(),eloss);//HIT for MIP: MIP in GAP Exiting
  63       GenerateFeedbacks(iCurrentChamber,eloss);//MIP+GAP+Exit
  64     }else//MIP in GAP going inside
  65       eloss   += gMC->Edep();
  66   }//MIP in GAP
  67 }//StepManager()
  68 //__________________________________________________________________________________________________
  69 Bool_t AliRICHv1::IsLostByFresnel()
  70 {
  71   TLorentzVector p4;
  72   Double_t mom[3],localMom[3];
  73   gMC->TrackMomentum(p4); mom[0]=p4(0);   mom[1]=p4(1);   mom[2]=p4(2);   mom[3]=p4(3);
  74   gMC->Gmtod(mom,localMom,2);
  75   Double_t localTc    = localMom[0]*localMom[0]+localMom[2]*localMom[2];
  76   Double_t localTheta = TMath::ATan2(TMath::Sqrt(localTc),localMom[1]);
  77   Double_t cotheta = TMath::Abs(TMath::Cos(localTheta));
  78   if(gMC->GetRandom()->Rndm() < Fresnel(p4.E()*1e9,cotheta,1)){
  79     if(GetDebug()) Info("IsLostByFresnel","");
  80     return kTRUE;
  81   }else
  82     return kFALSE;
  83 }//IsLostByFresnel()
  84 //__________________________________________________________________________________________________