/*
$Log$
+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
+
+Revision 1.20 2000/06/08 18:32:58 cblume
+Make code compliant to coding conventions
+
+Revision 1.19 2000/06/07 16:27:32 cblume
+Try to remove compiler warnings on Sun and HP
+
+Revision 1.18 2000/05/08 16:17:27 cblume
+Merge TRD-develop
+
+Revision 1.17.2.1 2000/05/08 14:59:16 cblume
+Made inline function non-virtual. Bug fix in setting sensitive chamber
+
+Revision 1.17 2000/02/28 19:10:26 cblume
+Include the new TRD classes
+
+Revision 1.16.4.1 2000/02/28 18:04:35 cblume
+Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
+
+Revision 1.16 1999/11/05 22:50:28 fca
+Do not use Atan, removed from ROOT too
+
+Revision 1.15 1999/11/02 17:20:19 fca
+initialise nbytes before using it
+
+Revision 1.14 1999/11/02 17:15:54 fca
+Correct ansi scoping not accepted by HP compilers
+
+Revision 1.13 1999/11/02 17:14:51 fca
+Correct ansi scoping not accepted by HP compilers
+
+Revision 1.12 1999/11/02 16:35:56 fca
+New version of TRD introduced
+
+Revision 1.11 1999/11/01 20:41:51 fca
+Added protections against using the wrong version of FRAME
+
+Revision 1.10 1999/09/29 09:24:35 fca
+Introduction of the Copyright and cvs Log
+
*/
///////////////////////////////////////////////////////////////////////////////
// //
-// Transition Radiation Detector version 1 -- coarse simulation //
-// This version has two detector arms, leaving the space in front of the //
-// HMPID and PHOS empty //
+// Transition Radiation Detector version 1 -- slow simulator //
// //
//Begin_Html
/*
-<img src="picts/AliTRDv1Class.gif">
+<img src="picts/AliTRDfullClass.gif">
*/
//End_Html
// //
// //
///////////////////////////////////////////////////////////////////////////////
+#include <stdlib.h>
+
#include <TMath.h>
-#include <TRandom.h>
#include <TVector.h>
+#include <TRandom.h>
+#include <TF1.h>
+#include <TLorentzVector.h>
-#include "AliTRDv1.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
+ //
+
+ fSensSelect = 0;
+ fSensPlane = -1;
+ fSensChamber = -1;
+ fSensSector = -1;
+ fSensSectorRange = 0;
+
+ fDeltaE = NULL;
+ fTR = NULL;
+
+}
//_____________________________________________________________________________
AliTRDv1::AliTRDv1(const char *name, const char *title)
:AliTRD(name, title)
{
//
- // Standard constructor for the Transition Radiation Detector version 1
+ // Standard constructor for Transition Radiation Detector version 1
//
- fIdSens = 0;
- fHitsOn = 0;
+ fSensSelect = 0;
+ fSensPlane = -1;
+ fSensChamber = -1;
+ fSensSector = -1;
+ fSensSectorRange = 0;
- fIdSpace1 = 0;
- fIdSpace2 = 0;
- fIdSpace3 = 0;
+ fDeltaE = NULL;
+ fTR = NULL;
- fIdChamber1 = 0;
- fIdChamber2 = 0;
- fIdChamber3 = 0;
+ SetBufferSize(128000);
+
+}
+
+//_____________________________________________________________________________
+AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
+{
+ //
+ // Copy constructor
+ //
+
+ ((AliTRDv1 &) trd).Copy(*this);
+
+}
+
+//_____________________________________________________________________________
+AliTRDv1::~AliTRDv1()
+{
+ //
+ // AliTRDv1 destructor
+ //
+
+ if (fDeltaE) delete fDeltaE;
+ if (fTR) delete fTR;
}
//_____________________________________________________________________________
-void AliTRDv1::CreateGeometry()
+AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
{
//
- // Create the GEANT geometry for the Transition Radiation Detector - Version 1
- // This version covers only part of the azimuth.
+ // Assignment operator
+ //
+
+ if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
+ return *this;
+
+}
+
+//_____________________________________________________________________________
+void AliTRDv1::Copy(TObject &trd)
+{
//
- // Author: Christoph Blume (C.Blume@gsi.de) 20/07/99
+ // Copy function
//
- Float_t xpos, ypos, zpos;
+ ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
+ ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
+ ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
+ ((AliTRDv1 &) trd).fSensSector = fSensSector;
+ ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
+
+ fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
+ fTR->Copy(*((AliTRDv1 &) trd).fTR);
+
+}
+
+//_____________________________________________________________________________
+void AliTRDv1::CreateGeometry()
+{
+ //
+ // Create the GEANT geometry for the Transition Radiation Detector - Version 1
+ // This version covers the full azimuth.
+ //
// Check that FRAME is there otherwise we have no place where to put the TRD
- AliModule* FRAME = gAlice->GetModule("FRAME");
- if (!FRAME) return;
+ AliModule* frame = gAlice->GetModule("FRAME");
+ if (!frame) return;
// Define the chambers
AliTRD::CreateGeometry();
- // Position the the TRD-sectors only in one TRD-volume in the spaceframe
- xpos = 0.;
- ypos = 0.;
- zpos = 0.;
- gMC->Gspos("TRD ",1,"BTR1",xpos,ypos,zpos,0,"ONLY");
-
}
//_____________________________________________________________________________
}
+//_____________________________________________________________________________
+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()
{
//
- // Initialise the Transition Radiation Detector after the geometry is built
+ // Initialise Transition Radiation Detector after geometry has been built.
//
AliTRD::Init();
- for (Int_t i = 0; i < 80; i++) printf("*");
+ if(fDebug) printf("%s: Slow simulator\n",ClassName());
+ if (fSensSelect) {
+ if (fSensPlane >= 0)
+ printf(" Only plane %d is sensitive\n",fSensPlane);
+ if (fSensChamber >= 0)
+ printf(" Only chamber %d is sensitive\n",fSensChamber);
+ if (fSensSector >= 0) {
+ Int_t sens1 = fSensSector;
+ Int_t sens2 = fSensSector + fSensSectorRange;
+ 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");
-
- // Identifier of the sensitive volume (amplification region)
- fIdSens = gMC->VolId("UL06");
- // Identifier of the TRD-spaceframe volumina
- fIdSpace1 = gMC->VolId("B028");
- fIdSpace2 = gMC->VolId("B029");
- fIdSpace3 = gMC->VolId("B030");
+ // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
+ const Float_t kPoti = 12.1;
+ // Maximum energy (50 keV);
+ const Float_t kEend = 50000.0;
+ // 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);
+
+ 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");
+}
+
+//_____________________________________________________________________________
+AliTRDsim *AliTRDv1::CreateTR()
+{
+ //
+ // Enables the simulation of TR
+ //
+
+ fTR = new AliTRDsim();
+ return fTR;
}
//_____________________________________________________________________________
-void AliTRDv1::StepManager()
+void AliTRDv1::SetSensPlane(Int_t iplane)
{
//
- // Procedure called at every step in the TRD
- // Fast simulator. If switched on, a hit is produced when a track
- // crosses the border between amplification region and pad plane.
+ // Defines the hit-sensitive plane (0-5)
//
- Int_t vol[3];
- Int_t iIdSens, icSens;
- Int_t iIdSpace, icSpace;
- Int_t iIdChamber, icChamber;
+ if ((iplane < 0) || (iplane > 5)) {
+ printf("Wrong input value: %d\n",iplane);
+ printf("Use standard setting\n");
+ fSensPlane = -1;
+ fSensSelect = 0;
+ return;
+ }
- Int_t secMap1[10] = { 3, 7, 8, 9, 10, 11, 2, 1, 18, 17 };
- Int_t secMap2[ 5] = { 16, 15, 14, 13, 12 };
- Int_t secMap3[ 3] = { 5, 6, 4 };
+ fSensSelect = 1;
+ fSensPlane = iplane;
- Float_t hits[4];
+}
- TLorentzVector p;
- TClonesArray &lhits = *fHits;
+//_____________________________________________________________________________
+void AliTRDv1::SetSensChamber(Int_t ichamber)
+{
+ //
+ // Defines the hit-sensitive chamber (0-4)
+ //
- // Writing out hits enabled?
- if (!(fHitsOn)) return;
+ if ((ichamber < 0) || (ichamber > 4)) {
+ printf("Wrong input value: %d\n",ichamber);
+ printf("Use standard setting\n");
+ fSensChamber = -1;
+ fSensSelect = 0;
+ return;
+ }
- // Use only charged tracks and count them only once per volume
- if (gMC->TrackCharge() &&
- gMC->IsTrackExiting()) {
-
- // Check on sensitive volume
- iIdSens = gMC->CurrentVolID(icSens);
- if (iIdSens == fIdSens) {
+ fSensSelect = 1;
+ fSensChamber = ichamber;
- gMC->TrackPosition(p);
- for (Int_t i = 0; i < 3; i++) hits[i] = p[i];
- // No charge created
- hits[3] = 0;
+}
- iIdSpace = gMC->CurrentVolOffID(4,icSpace );
- iIdChamber = gMC->CurrentVolOffID(1,icChamber);
+//_____________________________________________________________________________
+void AliTRDv1::SetSensSector(Int_t isector)
+{
+ //
+ // Defines the hit-sensitive sector (0-17)
+ //
- // The sector number
- if (iIdSpace == fIdSpace1)
- vol[0] = secMap1[icSpace-1];
- else if (iIdSpace == fIdSpace2)
- vol[0] = secMap2[icSpace-1];
- else if (iIdSpace == fIdSpace3)
- vol[0] = secMap3[icSpace-1];
+ SetSensSector(isector,1);
- // The chamber number
- // 1: outer left
- // 2: middle left
- // 3: inner
- // 4: middle right
- // 5: outer right
- if (iIdChamber == fIdChamber1)
- vol[1] = (hits[2] < 0 ? 1 : 5);
- else if (iIdChamber == fIdChamber2)
- vol[1] = (hits[2] < 0 ? 2 : 4);
- else if (iIdChamber == fIdChamber3)
- vol[1] = 3;
+}
- // The plane number
- vol[2] = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6;
+//_____________________________________________________________________________
+void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
+{
+ //
+ // Defines a range of hit-sensitive sectors. The range is defined by
+ // <isector> (0-17) as the starting point and <nsector> as the number
+ // of sectors to be included.
+ //
+
+ if ((isector < 0) || (isector > 17)) {
+ printf("Wrong input value <isector>: %d\n",isector);
+ printf("Use standard setting\n");
+ fSensSector = -1;
+ fSensSectorRange = 0;
+ fSensSelect = 0;
+ return;
+ }
+
+ if ((nsector < 1) || (nsector > 18)) {
+ printf("Wrong input value <nsector>: %d\n",nsector);
+ printf("Use standard setting\n");
+ fSensSector = -1;
+ fSensSectorRange = 0;
+ fSensSelect = 0;
+ return;
+ }
+
+ fSensSelect = 1;
+ fSensSector = isector;
+ fSensSectorRange = nsector;
- new(lhits[fNhits++]) AliTRDhit(fIshunt,gAlice->CurrentTrack(),vol,hits);
+}
+//_____________________________________________________________________________
+void AliTRDv1::StepManager()
+{
+ //
+ // Slow simulator. Every charged track produces electron cluster as hits
+ // along its path across the drift volume. The step size is set acording
+ // to Bethe-Bloch. The energy distribution of the delta electrons follows
+ // a spectrum taken from Ermilova et al.
+ //
+
+ Int_t pla = 0;
+ Int_t cha = 0;
+ Int_t sec = 0;
+ Int_t det = 0;
+ Int_t iPdg;
+ Int_t qTot;
+
+ Float_t hits[3];
+ Float_t moms[3];
+ Float_t random[1];
+ Float_t charge;
+ Float_t aMass;
+
+ 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;
+
+ const Int_t kNplan = AliTRDgeometry::Nplan();
+ const Double_t kBig = 1.0E+12;
+
+ // Ionization energy
+ 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;
+ // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
+ const Float_t kPrim = 48.0;
+ // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
+ const Float_t kPoti = 12.1;
+
+ // PDG code electron
+ const Int_t kPdgElectron = 11;
+
+ // Set the maximum step size to a very large number for all
+ // neutral particles and those outside the driftvolume
+ gMC->SetMaxStep(kBig);
+
+ // Use only charged tracks
+ if (( gMC->TrackCharge() ) &&
+ (!gMC->IsTrackStop() ) &&
+ (!gMC->IsTrackDisappeared())) {
+
+ // Inside a sensitive volume?
+ 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];
+
+ // The sector number (0 - 17)
+ // The numbering goes clockwise and starts at y = 0
+ Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
+ if (phi < 90.)
+ phi = phi + 270.;
+ else
+ phi = phi - 90.;
+ sec = ((Int_t) (phi / 20));
+
+ // 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 (fSensSelect) {
+ if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
+ if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
+ if (fSensSector >= 0) {
+ Int_t sens1 = fSensSector;
+ Int_t sens2 = fSensSector + fSensSectorRange;
+ sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
+ * AliTRDgeometry::Nsect();
+ if (sens1 < sens2) {
+ if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
+ }
+ else {
+ if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
+ }
+ }
+ }
+
+ // Add this hit
+ if (addthishit) {
+
+ // 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 {
+ AddHit(gAlice->CurrentTrack(),det,hits,qTot,kFALSE);
+ }
+
+ // Calculate the maximum step size for the next tracking step
+ // 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);
+ }
+
+ }
+
+ }
+
+ }
+
+ }
+
+}
+
+//_____________________________________________________________________________
+Double_t AliTRDv1::BetheBloch(Double_t bg)
+{
+ //
+ // Parametrization of the Bethe-Bloch-curve
+ // The parametrization is the same as for the TPC and is taken from Lehrhaus.
+ //
+
+ // This parameters have been adjusted to averaged values from GEANT
+ const Double_t kP1 = 7.17960e-02;
+ const Double_t kP2 = 8.54196;
+ const Double_t kP3 = 1.38065e-06;
+ const Double_t kP4 = 5.30972;
+ const Double_t kP5 = 2.83798;
+
+ // This parameters have been adjusted to Xe-data found in:
+ // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
+ //const Double_t kP1 = 0.76176E-1;
+ //const Double_t kP2 = 10.632;
+ //const Double_t kP3 = 3.17983E-6;
+ //const Double_t kP4 = 1.8631;
+ //const Double_t kP5 = 1.9479;
+
+ // 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 kBBMax;
+ }
+
+}
+
+//_____________________________________________________________________________
+Double_t Ermilova(Double_t *x, Double_t *)
+{
+ //
+ // Calculates the delta-ray energy distribution according to Ermilova.
+ // Logarithmic scale !
+ //
- }
+ Double_t energy;
+ Double_t dpos;
+ Double_t dnde;
+
+ Int_t pos1, pos2;
+
+ const Int_t kNv = 31;
+
+ Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
+ , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
+ , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
+ , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
+ , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
+ , 9.4727, 9.9035,10.3735,10.5966,10.8198
+ ,11.5129 };
+
+ Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
+ , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
+ , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
+ , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
+ , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
+ , 0.04 , 0.023, 0.015, 0.011, 0.01
+ , 0.004 };
+
+ energy = x[0];
+
+ // Find the position
+ pos1 = pos2 = 0;
+ dpos = 0;
+ do {
+ dpos = energy - vxe[pos2++];
+ }
+ while (dpos > 0);
+ pos2--;
+ if (pos2 > kNv) pos2 = kNv - 1;
+ pos1 = pos2 - 1;
+
+ // Differentiate between the sampling points
+ dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);
+
+ return dnde;
}
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff