/*
$Log$
+Revision 1.31 2002/02/11 14:25:27 cblume
+Geometry update, compressed hit structure
+
+Revision 1.30 2001/05/21 16:45:47 hristov
+Last minute changes (C.Blume)
+
+Revision 1.29 2001/05/16 14:57:28 alibrary
+New files for folders and Stack
+
+Revision 1.28 2001/05/07 08:03:22 cblume
+Generate also hits in the amplification region
+
+Revision 1.27 2001/03/30 14:40:15 cblume
+Update of the digitization parameter
+
+Revision 1.26 2000/11/30 17:38:08 cblume
+Changes to get in line with new STEER and EVGEN
+
+Revision 1.25 2000/11/15 14:30:16 cblume
+Fixed bug in calculating detector no. of extra hit
+
+Revision 1.24 2000/11/10 14:58:36 cblume
+Introduce additional hit with amplitude 0 at the chamber borders
+
+Revision 1.23 2000/11/01 14:53:21 cblume
+Merge with TRD-develop
+
+Revision 1.17.2.5 2000/10/15 23:40:01 cblume
+Remove AliTRDconst
+
+Revision 1.17.2.4 2000/10/06 16:49:46 cblume
+Made Getters const
+
+Revision 1.17.2.3 2000/10/04 16:34:58 cblume
+Replace include files by forward declarations
+
+Revision 1.17.2.2 2000/09/18 13:50:17 cblume
+Include TR photon generation and adapt to new AliTRDhit
+
+Revision 1.22 2000/06/27 13:08:50 cblume
+Changed to Copy(TObject &A) to appease the HP-compiler
+
Revision 1.21 2000/06/09 11:10:07 cblume
Compiler warnings and coding conventions, next round
///////////////////////////////////////////////////////////////////////////////
// //
-// Transition Radiation Detector version 2 -- slow simulator //
+// Transition Radiation Detector version 1 -- slow simulator //
// //
//Begin_Html
/*
// //
///////////////////////////////////////////////////////////////////////////////
+#include <stdlib.h>
+
#include <TMath.h>
#include <TVector.h>
#include <TRandom.h>
+#include <TF1.h>
+#include <TLorentzVector.h>
#include "AliRun.h"
#include "AliMC.h"
#include "AliConst.h"
#include "AliTRDv1.h"
+#include "AliTRDhit.h"
#include "AliTRDmatrix.h"
#include "AliTRDgeometry.h"
+#include "AliTRDsim.h"
ClassImp(AliTRDv1)
-
//_____________________________________________________________________________
AliTRDv1::AliTRDv1():AliTRD()
// Default constructor
//
- fIdSens = 0;
-
- fIdChamber1 = 0;
- fIdChamber2 = 0;
- fIdChamber3 = 0;
-
fSensSelect = 0;
fSensPlane = -1;
fSensChamber = -1;
fSensSectorRange = 0;
fDeltaE = NULL;
+ fTR = NULL;
}
// Standard constructor for Transition Radiation Detector version 1
//
- fIdSens = 0;
-
- fIdChamber1 = 0;
- fIdChamber2 = 0;
- fIdChamber3 = 0;
-
fSensSelect = 0;
fSensPlane = -1;
fSensChamber = -1;
fSensSectorRange = 0;
fDeltaE = NULL;
+ fTR = NULL;
SetBufferSize(128000);
//
if (fDeltaE) delete fDeltaE;
+ if (fTR) delete fTR;
}
// Copy function
//
- ((AliTRDv1 &) trd).fIdSens = fIdSens;
-
- ((AliTRDv1 &) trd).fIdChamber1 = fIdChamber1;
- ((AliTRDv1 &) trd).fIdChamber2 = fIdChamber2;
- ((AliTRDv1 &) trd).fIdChamber3 = fIdChamber3;
-
((AliTRDv1 &) trd).fSensSelect = fSensSelect;
((AliTRDv1 &) trd).fSensPlane = fSensPlane;
((AliTRDv1 &) trd).fSensChamber = fSensChamber;
((AliTRDv1 &) trd).fSensSector = fSensSector;
((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
- ((AliTRDv1 &) trd).fDeltaE = NULL;
+ fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
+ fTR->Copy(*((AliTRDv1 &) trd).fTR);
}
}
+//_____________________________________________________________________________
+void AliTRDv1::CreateTRhit(Int_t det)
+{
+ //
+ // Creates an electron cluster from a TR photon.
+ // The photon is assumed to be created a the end of the radiator. The
+ // distance after which it deposits its energy takes into account the
+ // absorbtion of the entrance window and of the gas mixture in drift
+ // volume.
+ //
+
+ // PDG code electron
+ const Int_t kPdgElectron = 11;
+
+ // Ionization energy
+ const Float_t kWion = 22.04;
+
+ // Maximum number of TR photons per track
+ const Int_t kNTR = 50;
+
+ TLorentzVector mom, pos;
+
+ // Create TR at the entrance of the chamber
+ if (gMC->IsTrackEntering()) {
+
+ // Create TR only for electrons
+ Int_t iPdg = gMC->TrackPid();
+ if (TMath::Abs(iPdg) != kPdgElectron) return;
+
+ Float_t eTR[kNTR];
+ Int_t nTR;
+
+ // Create TR photons
+ gMC->TrackMomentum(mom);
+ Float_t pTot = mom.Rho();
+ fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
+ if (nTR > kNTR) {
+ printf("AliTRDv1::CreateTRhit -- ");
+ printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
+ exit(1);
+ }
+
+ // Loop through the TR photons
+ for (Int_t iTR = 0; iTR < nTR; iTR++) {
+
+ Float_t energyMeV = eTR[iTR] * 0.001;
+ Float_t energyeV = eTR[iTR] * 1000.0;
+ Float_t absLength = 0;
+ Float_t sigma = 0;
+
+ // Take the absorbtion in the entrance window into account
+ Double_t muMy = fTR->GetMuMy(energyMeV);
+ sigma = muMy * fFoilDensity;
+ absLength = gRandom->Exp(sigma);
+ if (absLength < AliTRDgeometry::MyThick()) continue;
+
+ // The absorbtion cross sections in the drift gas
+ if (fGasMix == 1) {
+ // Gas-mixture (Xe/CO2)
+ Double_t muXe = fTR->GetMuXe(energyMeV);
+ Double_t muCO = fTR->GetMuCO(energyMeV);
+ sigma = (0.85 * muXe + 0.15 * muCO) * fGasDensity;
+ }
+ else {
+ // Gas-mixture (Xe/Isobutane)
+ Double_t muXe = fTR->GetMuXe(energyMeV);
+ Double_t muBu = fTR->GetMuBu(energyMeV);
+ sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity;
+ }
+
+ // The distance after which the energy of the TR photon
+ // is deposited.
+ absLength = gRandom->Exp(sigma);
+ if (absLength > AliTRDgeometry::DrThick()) continue;
+
+ // The position of the absorbtion
+ Float_t posHit[3];
+ gMC->TrackPosition(pos);
+ posHit[0] = pos[0] + mom[0] / pTot * absLength;
+ posHit[1] = pos[1] + mom[1] / pTot * absLength;
+ posHit[2] = pos[2] + mom[2] / pTot * absLength;
+
+ // Create the charge
+ Int_t q = ((Int_t) (energyeV / kWion));
+
+ // Add the hit to the array. TR photon hits are marked
+ // by negative charge
+ AddHit(gAlice->CurrentTrack(),det,posHit,-q,kTRUE);
+
+ }
+
+ }
+
+}
+
//_____________________________________________________________________________
void AliTRDv1::Init()
{
AliTRD::Init();
- printf(" Slow simulator\n\n");
+ if(fDebug) printf("%s: Slow simulator\n",ClassName());
if (fSensSelect) {
if (fSensPlane >= 0)
printf(" Only plane %d is sensitive\n",fSensPlane);
if (fSensSector >= 0) {
Int_t sens1 = fSensSector;
Int_t sens2 = fSensSector + fSensSectorRange;
- sens2 -= ((Int_t) (sens2 / kNsect)) * kNsect;
+ sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
+ * AliTRDgeometry::Nsect();
printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
}
}
+ if (fTR)
+ printf("%s: TR simulation on\n",ClassName());
+ else
+ printf("%s: TR simulation off\n",ClassName());
printf("\n");
// First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
// Ermilova distribution for the delta-ray spectrum
Float_t poti = TMath::Log(kPoti);
Float_t eEnd = TMath::Log(kEend);
- fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
+ fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
- // Identifier of the sensitive volume (drift region)
- fIdSens = gMC->VolId("UL05");
+ if(fDebug) {
+ printf("%s: ",ClassName());
+ for (Int_t i = 0; i < 80; i++) printf("*");
+ printf("\n");
+ }
- // Identifier of the TRD-driftchambers
- fIdChamber1 = gMC->VolId("UCIO");
- fIdChamber2 = gMC->VolId("UCIM");
- fIdChamber3 = gMC->VolId("UCII");
+}
- for (Int_t i = 0; i < 80; i++) printf("*");
- printf("\n");
+//_____________________________________________________________________________
+AliTRDsim *AliTRDv1::CreateTR()
+{
+ //
+ // Enables the simulation of TR
+ //
+
+ fTR = new AliTRDsim();
+ return fTR;
}
// a spectrum taken from Ermilova et al.
//
- Int_t iIdSens, icSens;
- Int_t iIdSpace, icSpace;
- Int_t iIdChamber, icChamber;
Int_t pla = 0;
Int_t cha = 0;
Int_t sec = 0;
+ Int_t det = 0;
Int_t iPdg;
+ Int_t qTot;
- Int_t det[1];
-
- Float_t hits[4];
+ Float_t hits[3];
+ Float_t moms[3];
Float_t random[1];
Float_t charge;
Float_t aMass;
- Double_t pTot;
- Double_t qTot;
+ Double_t pTot = 0;
Double_t eDelta;
Double_t betaGamma, pp;
+ Double_t stepSize;
+
+ Bool_t drRegion = kFALSE;
+ Bool_t amRegion = kFALSE;
+
+ TString cIdCurrent;
+ TString cIdSensDr = "J";
+ TString cIdSensAm = "K";
+ Char_t cIdChamber[3];
+ cIdChamber[2] = 0;
TLorentzVector pos, mom;
- TClonesArray &lhits = *fHits;
- const Double_t kBig = 1.0E+12;
+ const Int_t kNplan = AliTRDgeometry::Nplan();
+ const Double_t kBig = 1.0E+12;
// Ionization energy
- const Float_t kWion = 22.04;
- // Maximum energy for e+ e- g for the step-size calculation
- const Float_t kPTotMax = 0.002;
+ const Float_t kWion = 22.04;
+ // Maximum momentum for e+ e- g
+ const Float_t kPTotMaxEl = 0.002;
+ // Minimum energy for the step size adjustment
+ const Float_t kEkinMinStep = 1.0e-5;
// Plateau value of the energy-loss for electron in xenon
// taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
//const Double_t kPlateau = 1.70;
// the averaged value (26/3/99)
- const Float_t kPlateau = 1.55;
+ const Float_t kPlateau = 1.55;
// dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
- const Float_t kPrim = 48.0;
+ const Float_t kPrim = 48.0;
// First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
- const Float_t kPoti = 12.1;
+ const Float_t kPoti = 12.1;
// PDG code electron
const Int_t kPdgElectron = 11;
(!gMC->IsTrackDisappeared())) {
// Inside a sensitive volume?
- iIdSens = gMC->CurrentVolID(icSens);
- if (iIdSens == fIdSens) {
-
- iIdSpace = gMC->CurrentVolOffID(4,icSpace );
- iIdChamber = gMC->CurrentVolOffID(1,icChamber);
-
- // Calculate the energy of the delta-electrons
- eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
- eDelta = TMath::Max(eDelta,0.0);
-
- // The number of secondary electrons created
- qTot = (Double_t) ((Int_t) (eDelta / kWion) + 1);
+ drRegion = kFALSE;
+ amRegion = kFALSE;
+ cIdCurrent = gMC->CurrentVolName();
+ if (cIdCurrent[1] == cIdSensDr) {
+ drRegion = kTRUE;
+ }
+ if (cIdCurrent[1] == cIdSensAm) {
+ amRegion = kTRUE;
+ }
+ if (drRegion || amRegion) {
// The hit coordinates and charge
gMC->TrackPosition(pos);
hits[0] = pos[0];
hits[1] = pos[1];
hits[2] = pos[2];
- hits[3] = qTot;
// The sector number (0 - 17)
// The numbering goes clockwise and starts at y = 0
phi = phi - 90.;
sec = ((Int_t) (phi / 20));
- // The chamber number
- // 0: outer left
- // 1: middle left
- // 2: inner
- // 3: middle right
- // 4: outer right
- if (iIdChamber == fIdChamber1)
- cha = (hits[2] < 0 ? 0 : 4);
- else if (iIdChamber == fIdChamber2)
- cha = (hits[2] < 0 ? 1 : 3);
- else if (iIdChamber == fIdChamber3)
- cha = 2;
-
- // The plane number
- // The numbering starts at the innermost plane
- pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
+ // The plane and chamber number
+ cIdChamber[0] = cIdCurrent[2];
+ cIdChamber[1] = cIdCurrent[3];
+ Int_t idChamber = atoi(cIdChamber);
+ cha = ((Int_t) idChamber / kNplan);
+ pla = ((Int_t) idChamber % kNplan);
// Check on selected volumes
Int_t addthishit = 1;
if (fSensSector >= 0) {
Int_t sens1 = fSensSector;
Int_t sens2 = fSensSector + fSensSectorRange;
- sens2 -= ((Int_t) (sens2 / kNsect)) * kNsect;
+ sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
+ * AliTRDgeometry::Nsect();
if (sens1 < sens2) {
if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
}
// Add this hit
if (addthishit) {
- det[0] = fGeometry->GetDetector(pla,cha,sec);
- new(lhits[fNhits++]) AliTRDhit(fIshunt
- ,gAlice->CurrentTrack()
- ,det
- ,hits);
-
- // The energy loss according to Bethe Bloch
- gMC->TrackMomentum(mom);
- pTot = mom.Rho();
- iPdg = TMath::Abs(gMC->TrackPid());
- if ( (iPdg != kPdgElectron) ||
- ((iPdg == kPdgElectron) && (pTot < kPTotMax))) {
- aMass = gMC->TrackMass();
- betaGamma = pTot / aMass;
- pp = kPrim * BetheBloch(betaGamma);
- // Take charge > 1 into account
- charge = gMC->TrackCharge();
- if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
- }
- // Electrons above 20 Mev/c are at the plateau
+ // The detector number
+ det = fGeometry->GetDetector(pla,cha,sec);
+
+ // Special hits and TR photons only in the drift region
+ if (drRegion) {
+
+ // Create some special hits with amplitude 0 at the entrance and
+ // exit of each chamber that contain the momentum components of the particle
+ if (gMC->IsTrackEntering() || gMC->IsTrackExiting()) {
+ gMC->TrackMomentum(mom);
+ moms[0] = mom[0];
+ moms[1] = mom[1];
+ moms[2] = mom[2];
+ AddHit(gAlice->CurrentTrack(),det,moms,0,kTRUE);
+ AddHit(gAlice->CurrentTrack(),det,hits,0,kTRUE);
+ }
+
+ // Create the hits from TR photons
+ if (fTR) CreateTRhit(det);
+
+ }
+
+ // Calculate the energy of the delta-electrons
+ eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
+ eDelta = TMath::Max(eDelta,0.0);
+
+ // The number of secondary electrons created
+ qTot = ((Int_t) (eDelta / kWion) + 1);
+
+ // Create a new dEdx hit
+ if (drRegion) {
+ AddHit(gAlice->CurrentTrack(),det,hits,qTot,kTRUE);
+ }
else {
- pp = kPrim * kPlateau;
- }
-
+ AddHit(gAlice->CurrentTrack(),det,hits,qTot,kFALSE);
+ }
+
// Calculate the maximum step size for the next tracking step
- if (pp > 0) {
- do
- gMC->Rndm(random,1);
- while ((random[0] == 1.) || (random[0] == 0.));
- gMC->SetMaxStep( - TMath::Log(random[0]) / pp);
+ // Produce only one hit if Ekin is below cutoff
+ aMass = gMC->TrackMass();
+ if ((gMC->Etot() - aMass) > kEkinMinStep) {
+
+ // The energy loss according to Bethe Bloch
+ iPdg = TMath::Abs(gMC->TrackPid());
+ if ( (iPdg != kPdgElectron) ||
+ ((iPdg == kPdgElectron) && (pTot < kPTotMaxEl))) {
+ gMC->TrackMomentum(mom);
+ pTot = mom.Rho();
+ betaGamma = pTot / aMass;
+ pp = kPrim * BetheBloch(betaGamma);
+ // Take charge > 1 into account
+ charge = gMC->TrackCharge();
+ if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
+ }
+ // Electrons above 20 Mev/c are at the plateau
+ else {
+ pp = kPrim * kPlateau;
+ }
+
+ if (pp > 0) {
+ do
+ gMC->Rndm(random,1);
+ while ((random[0] == 1.) || (random[0] == 0.));
+ stepSize = - TMath::Log(random[0]) / pp;
+ gMC->SetMaxStep(stepSize);
+ }
+
}
}
- else {
- // set step size to maximal value
- gMC->SetMaxStep(kBig);
- }
}
//const Double_t kP4 = 1.8631;
//const Double_t kP5 = 1.9479;
- if (bg > 0) {
+ // Lower cutoff of the Bethe-Bloch-curve to limit step sizes
+ const Double_t kBgMin = 0.8;
+ const Double_t kBBMax = 6.83298;
+ //const Double_t kBgMin = 0.6;
+ //const Double_t kBBMax = 17.2809;
+ //const Double_t kBgMin = 0.4;
+ //const Double_t kBBMax = 82.0;
+
+ if (bg > kBgMin) {
Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
Double_t aa = TMath::Power(yy,kP4);
Double_t bb = TMath::Power((1./bg),kP5);
bb = TMath::Log(kP3 + bb);
return ((kP2 - aa - bb)*kP1 / aa);
}
- else
- return 0;
+ else {
+ return kBBMax;
+ }
}
}
while (dpos > 0);
pos2--;
- if (pos2 > kNv) pos2 = kNv;
+ if (pos2 > kNv) pos2 = kNv - 1;
pos1 = pos2 - 1;
// Differentiate between the sampling points
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff