X-Git-Url: http://git.uio.no/git/?a=blobdiff_plain;f=TRD%2FAliTRDv1.cxx;h=77208541b8e3b437bfb2809393782e35121a93d4;hb=878fa0b3d4ee196b1e5cbd9da488c4109517c0f3;hp=e2dce3eb7791a1ff12cc05f277014515b1dfd301;hpb=ab76897d77dde6b0b3859ee87ef2a5b304a27eb0;p=u%2Fmrichter%2FAliRoot.git
diff --git a/TRD/AliTRDv1.cxx b/TRD/AliTRDv1.cxx
index e2dce3eb779..77208541b8e 100644
--- a/TRD/AliTRDv1.cxx
+++ b/TRD/AliTRDv1.cxx
@@ -13,87 +13,252 @@
* provided "as is" without express or implied warranty. *
**************************************************************************/
-/*
-$Log$
-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 //
-// //
-//Begin_Html
-/*
-
-*/
-//End_Html
-// //
-// //
-///////////////////////////////////////////////////////////////////////////////
-
-#include
+/* $Id$ */
+////////////////////////////////////////////////////////////////////////////
+// //
+// Transition Radiation Detector version 1 -- slow simulator //
+// //
+////////////////////////////////////////////////////////////////////////////
+
+#include
+
+#include
+#include
#include
#include
#include
+#include
+#include
+#include
+#include
-#include "AliTRDv1.h"
-#include "AliRun.h"
-#include "AliMC.h"
#include "AliConst.h"
-
+#include "AliLog.h"
+#include "AliTrackReference.h"
+#include "AliMC.h"
+#include "AliRun.h"
+#include "AliGeomManager.h"
+
+#include "AliTRDgeometry.h"
+#include "AliTRDCommonParam.h"
+#include "AliTRDhit.h"
+#include "AliTRDsimTR.h"
+#include "AliTRDv1.h"
+
ClassImp(AliTRDv1)
+
+//_____________________________________________________________________________
+AliTRDv1::AliTRDv1()
+ :AliTRD()
+ ,fTRon(kFALSE)
+ ,fTR(NULL)
+ ,fTypeOfStepManager(0)
+ ,fStepSize(0)
+ ,fWion(0)
+ ,fDeltaE(NULL)
+ ,fDeltaG(NULL)
+ ,fTrackLength0(0)
+ ,fPrimaryTrackPid(0)
+{
+ //
+ // Default constructor
+ //
+
+}
//_____________________________________________________________________________
AliTRDv1::AliTRDv1(const char *name, const char *title)
- :AliTRD(name, title)
+ :AliTRD(name,title)
+ ,fTRon(kTRUE)
+ ,fTR(NULL)
+ ,fTypeOfStepManager(2)
+ ,fStepSize(0.1)
+ ,fWion(0)
+ ,fDeltaE(NULL)
+ ,fDeltaG(NULL)
+ ,fTrackLength0(0)
+ ,fPrimaryTrackPid(0)
{
//
- // Standard constructor for the Transition Radiation Detector version 1
+ // Standard constructor for Transition Radiation Detector version 1
//
- fIdSens = 0;
- fHitsOn = 0;
+ SetBufferSize(128000);
+
+ if (AliTRDCommonParam::Instance()->IsXenon()) {
+ fWion = 23.53; // Ionization energy XeCO2 (85/15)
+ }
+ else if (AliTRDCommonParam::Instance()->IsArgon()) {
+ fWion = 27.21; // Ionization energy ArCO2 (82/18)
+ }
+ else {
+ AliFatal("Wrong gas mixture");
+ exit(1);
+ }
+
+}
- fIdSpace1 = 0;
- fIdSpace2 = 0;
- fIdSpace3 = 0;
+//_____________________________________________________________________________
+AliTRDv1::~AliTRDv1()
+{
+ //
+ // AliTRDv1 destructor
+ //
- fIdChamber1 = 0;
- fIdChamber2 = 0;
- fIdChamber3 = 0;
+ if (fDeltaE) {
+ delete fDeltaE;
+ fDeltaE = 0;
+ }
+
+ if (fDeltaG) {
+ delete fDeltaG;
+ fDeltaG = 0;
+ }
+
+ if (fTR) {
+ delete fTR;
+ fTR = 0;
+ }
}
//_____________________________________________________________________________
-void AliTRDv1::CreateGeometry()
+void AliTRDv1::AddAlignableVolumes() const
{
//
- // Create the GEANT geometry for the Transition Radiation Detector - Version 1
- // This version covers only part of the azimuth.
+ // Create entries for alignable volumes associating the symbolic volume
+ // name with the corresponding volume path. Needs to be syncronized with
+ // eventual changes in the geometry.
//
- // Author: Christoph Blume (C.Blume@gsi.de) 20/07/99
+
+ TString volPath;
+ TString symName;
+
+ TString vpStr = "ALIC_1/B077_1/BSEGMO";
+ TString vpApp1 = "_1/BTRD";
+ TString vpApp2 = "_1";
+ TString vpApp3a = "/UTR1_1/UTS1_1/UTI1_1/UT";
+ TString vpApp3b = "/UTR2_1/UTS2_1/UTI2_1/UT";
+ TString vpApp3c = "/UTR3_1/UTS3_1/UTI3_1/UT";
+
+ TString snStr = "TRD/sm";
+ TString snApp1 = "/st";
+ TString snApp2 = "/pl";
+
//
+ // The super modules
+ // The symbolic names are: TRD/sm00
+ // ...
+ // TRD/sm17
+ //
+ for (Int_t isector = 0; isector < AliTRDgeometry::Nsector(); isector++) {
+
+ volPath = vpStr;
+ volPath += isector;
+ volPath += vpApp1;
+ volPath += isector;
+ volPath += vpApp2;
+
+ symName = snStr;
+ symName += Form("%02d",isector);
+
+ gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data());
+
+ }
+
+ //
+ // The readout chambers
+ // The symbolic names are: TRD/sm00/st0/pl0
+ // ...
+ // TRD/sm17/st4/pl5
+ //
+ AliGeomManager::ELayerID idTRD1 = AliGeomManager::kTRD1;
+ Int_t layer, modUID;
+
+ for (Int_t isector = 0; isector < AliTRDgeometry::Nsector(); isector++) {
- Float_t xpos, ypos, zpos;
+ if (fGeometry->GetSMstatus(isector) == 0) continue;
+
+ for (Int_t istack = 0; istack < AliTRDgeometry::Nstack(); istack++) {
+ for (Int_t ilayer = 0; ilayer < AliTRDgeometry::Nlayer(); ilayer++) {
+
+ layer = idTRD1 + ilayer;
+ modUID = AliGeomManager::LayerToVolUIDSafe(layer,isector*5+istack);
+
+ Int_t idet = AliTRDgeometry::GetDetectorSec(ilayer,istack);
+
+ volPath = vpStr;
+ volPath += isector;
+ volPath += vpApp1;
+ volPath += isector;
+ volPath += vpApp2;
+ switch (isector) {
+ case 13:
+ case 14:
+ case 15:
+ if (istack == 2) {
+ continue;
+ }
+ volPath += vpApp3c;
+ break;
+ case 11:
+ case 12:
+ volPath += vpApp3b;
+ break;
+ default:
+ volPath += vpApp3a;
+ };
+ volPath += Form("%02d",idet);
+ volPath += vpApp2;
+
+ symName = snStr;
+ symName += Form("%02d",isector);
+ symName += snApp1;
+ symName += istack;
+ symName += snApp2;
+ symName += ilayer;
+
+ TGeoPNEntry *alignableEntry =
+ gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data(),modUID);
+
+ // Add the tracking to local matrix following the TPC example
+ if (alignableEntry) {
+ TGeoHMatrix *globMatrix = alignableEntry->GetGlobalOrig();
+ Double_t sectorAngle = 20.0 * (isector % 18) + 10.0;
+ TGeoHMatrix *t2lMatrix = new TGeoHMatrix();
+ t2lMatrix->RotateZ(sectorAngle);
+ t2lMatrix->MultiplyLeft(&(globMatrix->Inverse()));
+ alignableEntry->SetMatrix(t2lMatrix);
+ }
+ else {
+ AliError(Form("Alignable entry %s is not valid!",symName.Data()));
+ }
+
+ }
+ }
+ }
+
+}
+
+//_____________________________________________________________________________
+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) {
+ AliError("TRD needs FRAME to be present\n");
+ 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");
-
}
//_____________________________________________________________________________
@@ -108,124 +273,997 @@ void AliTRDv1::CreateMaterials()
}
//_____________________________________________________________________________
-void AliTRDv1::Init()
+void AliTRDv1::CreateTRhit(Int_t det)
{
//
- // Initialise the Transition Radiation Detector after the geometry is built
+ // 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.
//
- printf("**************************************"
- " TRD "
- "**************************************\n");
- printf("\n Version 1 of TRD initialing, "
- "with openings for PHOS and RICH\n\n");
+ // Maximum number of TR photons per track
+ const Int_t kNTR = 50;
+
+ TLorentzVector mom;
+ TLorentzVector pos;
+
+ Float_t eTR[kNTR];
+ Int_t nTR;
+
+ // Create TR photons
+ gMC->TrackMomentum(mom);
+ Float_t pTot = mom.Rho();
+ fTR->CreatePhotons(11,pTot,nTR,eTR);
+ if (nTR > kNTR) {
+ AliFatal(Form("Boundary error: nTR = %d, kNTR = %d",nTR,kNTR));
+ }
+
+ // 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 = 0.0;
+ Float_t sigma = 0.0;
+
+ // Take the absorbtion in the entrance window into account
+ Double_t muMy = fTR->GetMuMy(energyMeV);
+ sigma = muMy * fFoilDensity;
+ if (sigma > 0.0) {
+ absLength = gRandom->Exp(1.0/sigma);
+ if (absLength < AliTRDgeometry::MyThick()) {
+ continue;
+ }
+ }
+ else {
+ continue;
+ }
+
+ // The absorbtion cross sections in the drift gas
+ // Gas-mixture (Xe/CO2)
+ Double_t muNo = 0.0;
+ if (AliTRDCommonParam::Instance()->IsXenon()) {
+ muNo = fTR->GetMuXe(energyMeV);
+ }
+ else if (AliTRDCommonParam::Instance()->IsArgon()) {
+ muNo = fTR->GetMuAr(energyMeV);
+ }
+ Double_t muCO = fTR->GetMuCO(energyMeV);
+ sigma = (fGasNobleFraction * muNo + (1.0 - fGasNobleFraction) * muCO)
+ * fGasDensity
+ * fTR->GetTemp();
+
+ // The distance after which the energy of the TR photon
+ // is deposited.
+ if (sigma > 0.0) {
+ absLength = gRandom->Exp(1.0/sigma);
+ if (absLength > (AliTRDgeometry::DrThick()
+ + AliTRDgeometry::AmThick())) {
+ continue;
+ }
+ }
+ else {
+ 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 / fWion));
+
+ // Add the hit to the array. TR photon hits are marked
+ // by negative charge
+ AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
+ ,det
+ ,posHit
+ ,-q
+ ,gMC->TrackTime()*1.0e06
+ ,kTRUE);
+
+ }
+
+}
+
+//_____________________________________________________________________________
+void AliTRDv1::Init()
+{
+ //
+ // Initialise Transition Radiation Detector after geometry has been built.
+ //
AliTRD::Init();
+ AliDebug(1,"Slow simulator\n");
+
+ // Switch on TR simulation as default
+ if (!fTRon) {
+ AliInfo("TR simulation off");
+ }
+ else {
+ fTR = new AliTRDsimTR();
+ }
+
+ // First ionization potential (eV) for the gas mixture
+ 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);
+
+ // Ermilova distribution for the delta-ray spectrum
+ fDeltaE = new TF1("deltae" ,Ermilova ,poti,eEnd,0);
+
+ // Geant3 distribution for the delta-ray spectrum
+ fDeltaG = new TF1("deltag",IntSpecGeant,2.421257,28.536469,0);
+
+ AliDebug(1,"+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
+
+}
+
+//_____________________________________________________________________________
+void AliTRDv1::StepManager()
+{
//
- // Check that FRAME is there otherwise we have no place where to
- // put TRD
- AliModule* FRAME=gAlice->GetModule("FRAME");
- if(!FRAME) {
- Error("Ctor","TRD needs FRAME to be present\n");
- exit(1);
- } else
- if(FRAME->IsVersion()!=0) {
- Error("Ctor","FRAME version 0 needed with this version of TRD\n");
- exit(1);
+ // Slow simulator. Every charged track produces electron cluster as hits
+ // along its path across the drift volume.
+ //
+
+ switch (fTypeOfStepManager) {
+ case 0:
+ StepManagerErmilova();
+ break;
+ case 1:
+ StepManagerGeant();
+ break;
+ case 2:
+ StepManagerFixedStep();
+ break;
+ default:
+ AliWarning("Not a valid Step Manager.");
+ }
+
+}
+
+//_____________________________________________________________________________
+void AliTRDv1::SelectStepManager(Int_t t)
+{
+ //
+ // Selects a step manager type:
+ // 0 - Ermilova
+ // 1 - Geant3
+ // 2 - Fixed step size
+ //
+
+ fTypeOfStepManager = t;
+ AliInfo(Form("Step Manager type %d was selected",fTypeOfStepManager));
+
+}
+
+//_____________________________________________________________________________
+void AliTRDv1::StepManagerGeant()
+{
+ //
+ // 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 Geant3.
+ //
+ // Works only for Xe/CO2!!
+ //
+ // Version by A. Bercuci
+ //
+
+ Int_t layer = 0;
+ Int_t stack = 0;
+ Int_t sector = 0;
+ Int_t det = 0;
+ Int_t iPdg;
+ Int_t qTot;
+
+ Float_t hits[3];
+ Float_t charge;
+ Float_t aMass;
+
+ Double_t pTot = 0;
+ Double_t eDelta;
+ Double_t betaGamma;
+ Double_t pp;
+ Double_t stepSize = 0;
+
+ Bool_t drRegion = kFALSE;
+ Bool_t amRegion = kFALSE;
+
+ TString cIdPath;
+ Char_t cIdSector[3];
+ cIdSector[2] = 0;
+
+ TString cIdCurrent;
+ TString cIdSensDr = "J";
+ TString cIdSensAm = "K";
+ Char_t cIdChamber[3];
+ cIdChamber[2] = 0;
+
+ TLorentzVector pos;
+ TLorentzVector mom;
+
+ TArrayI processes;
+
+ const Int_t kNlayer = AliTRDgeometry::Nlayer();
+ const Int_t kNstack = AliTRDgeometry::Nstack();
+ const Int_t kNdetsec = kNlayer * kNstack;
+
+ const Double_t kBig = 1.0e+12; // Infinitely big
+ const Float_t kPTotMaxEl = 0.002; // Maximum momentum for e+ e- g
+
+ // Minimum energy for the step size adjustment
+ const Float_t kEkinMinStep = 1.0e-5;
+ // energy threshold for production of delta electrons
+ const Float_t kECut = 1.0e4;
+ // Parameters entering the parametrized range for delta electrons
+ const Float_t kRa = 5.37e-4;
+ const Float_t kRb = 0.9815;
+ const Float_t kRc = 3.123e-3;
+ // Gas density -> To be made user adjustable !
+ // [0.85*0.00549+0.15*0.00186 (Xe-CO2 85-15)]
+ const Float_t kRho = 0.004945 ;
+
+ // Plateau value of the energy-loss for electron in xenon
+ // 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 = 19.34;
+ // 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->IsTrackDisappeared())) {
+
+ // Inside a sensitive volume?
+ drRegion = kFALSE;
+ amRegion = kFALSE;
+ cIdCurrent = gMC->CurrentVolName();
+ if (cIdSensDr == cIdCurrent[1]) {
+ drRegion = kTRUE;
}
+ if (cIdSensAm == cIdCurrent[1]) {
+ 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), according to standard coordinate system
+ cIdPath = gGeoManager->GetPath();
+ cIdSector[0] = cIdPath[21];
+ cIdSector[1] = cIdPath[22];
+ sector = atoi(cIdSector);
+
+ // The layer and stack number
+ cIdChamber[0] = cIdCurrent[2];
+ cIdChamber[1] = cIdCurrent[3];
+ Int_t idChamber = (atoi(cIdChamber) % kNdetsec);
+ stack = ((Int_t) idChamber / kNlayer);
+ layer = ((Int_t) idChamber % kNlayer);
+
+ // The detector number
+ det = fGeometry->GetDetector(layer,stack,sector);
+
+ // Special hits only in the drift region
+ if ((drRegion) &&
+ (gMC->IsTrackEntering())) {
+
+ // Create a track reference at the entrance of each
+ // chamber that contains the momentum components of the particle
+ gMC->TrackMomentum(mom);
+ AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD);
+
+ // Create the hits from TR photons if electron/positron is
+ // entering the drift volume
+ if ((fTR) &&
+ (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) {
+ CreateTRhit(det);
+ }
+
+ }
+ else if ((amRegion) &&
+ (gMC->IsTrackExiting())) {
+
+ // Create a track reference at the exit of each
+ // chamber that contains the momentum components of the particle
+ gMC->TrackMomentum(mom);
+ AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD);
+
+ }
+
+ // Calculate the energy of the delta-electrons
+ // modified by Alex Bercuci (A.Bercuci@gsi.de) on 26.01.06
+ // take into account correlation with the underlying GEANT tracking
+ // mechanism. see
+ // http://www-linux.gsi.de/~abercuci/Contributions/TRD/index.html
+ //
+ // determine the most significant process (last on the processes list)
+ // which caused this hit
+ gMC->StepProcesses(processes);
+ Int_t nofprocesses = processes.GetSize();
+ Int_t pid;
+ if (!nofprocesses) {
+ pid = 0;
+ }
+ else {
+ pid = processes[nofprocesses-1];
+ }
+
+ // Generate Edep according to GEANT parametrisation
+ eDelta = TMath::Exp(fDeltaG->GetRandom()) - kPoti;
+ eDelta = TMath::Max(eDelta,0.0);
+ Float_t prRange = 0.0;
+ Float_t range = gMC->TrackLength() - fTrackLength0;
+ // merge GEANT tracker information with locally cooked one
+ if (gAlice->GetMCApp()->GetCurrentTrackNumber() == fPrimaryTrackPid) {
+ if (pid == 27) {
+ if (eDelta >= kECut) {
+ prRange = kRa * eDelta * 0.001
+ * (1.0 - kRb / (1.0 + kRc * eDelta * 0.001)) / kRho;
+ if (prRange >= (3.7 - range)) {
+ eDelta *= 0.1;
+ }
+ }
+ }
+ else if (pid == 1) {
+ if (eDelta < kECut) {
+ eDelta *= 0.5;
+ }
+ else {
+ prRange = kRa * eDelta * 0.001
+ * (1.0 - kRb / (1.0 + kRc * eDelta * 0.001)) / kRho;
+ if (prRange >= ((AliTRDgeometry::DrThick()
+ + AliTRDgeometry::AmThick()) - range)) {
+ eDelta *= 0.05;
+ }
+ else {
+ eDelta *= 0.5;
+ }
+ }
+ }
+ else {
+ eDelta = 0.0;
+ }
+ }
+ else {
+ eDelta = 0.0;
+ }
+
+ // Generate the electron cluster size
+ if (eDelta > 0.0) {
+
+ qTot = ((Int_t) (eDelta / fWion) + 1);
+
+ // Create a new dEdx hit
+ AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
+ ,det
+ ,hits
+ ,qTot
+ ,gMC->TrackTime()*1.0e06
+ ,drRegion);
+
+ }
+
+ // 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 = BetheBlochGeant(betaGamma);
+ // Take charge > 1 into account
+ charge = gMC->TrackCharge();
+ if (TMath::Abs(charge) > 1) {
+ pp = pp * charge*charge;
+ }
+ }
+ else {
+ // Electrons above 20 Mev/c are at the plateau
+ pp = kPrim * kPlateau;
+ }
+
+ Int_t nsteps = 0;
+ do {
+ nsteps = gRandom->Poisson(pp);
+ } while(!nsteps);
+ stepSize = 1.0 / nsteps;
+ gMC->SetMaxStep(stepSize);
+
+ }
+
+ }
+
+ }
+
+}
+
+//_____________________________________________________________________________
+void AliTRDv1::StepManagerErmilova()
+{
+ //
+ // 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.
+ //
+ // Works only for Xe/CO2!!
+ //
+
+ Int_t layer = 0;
+ Int_t stack = 0;
+ Int_t sector = 0;
+ Int_t det = 0;
+ Int_t iPdg;
+ Int_t qTot;
+
+ Float_t hits[3];
+ Double_t random[1];
+ Float_t charge;
+ Float_t aMass;
+
+ Double_t pTot = 0.0;
+ Double_t eDelta;
+ Double_t betaGamma;
+ Double_t pp;
+ Double_t stepSize;
+
+ Bool_t drRegion = kFALSE;
+ Bool_t amRegion = kFALSE;
+
+ TString cIdPath;
+ Char_t cIdSector[3];
+ cIdSector[2] = 0;
+
+ TString cIdCurrent;
+ TString cIdSensDr = "J";
+ TString cIdSensAm = "K";
+ Char_t cIdChamber[3];
+ cIdChamber[2] = 0;
+
+ TLorentzVector pos;
+ TLorentzVector mom;
+
+ const Int_t kNlayer = AliTRDgeometry::Nlayer();
+ const Int_t kNstack = AliTRDgeometry::Nstack();
+ const Int_t kNdetsec = kNlayer * kNstack;
+
+ const Double_t kBig = 1.0e+12; // Infinitely big
+ const Float_t kPTotMaxEl = 0.002; // Maximum momentum for e+ e- g
+
+ // Minimum energy for the step size adjustment
+ const Float_t kEkinMinStep = 1.0e-5;
+
+ // Plateau value of the energy-loss for electron in xenon
+ // 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->IsTrackDisappeared())) {
+
+ // Inside a sensitive volume?
+ drRegion = kFALSE;
+ amRegion = kFALSE;
+ cIdCurrent = gMC->CurrentVolName();
+ if (cIdSensDr == cIdCurrent[1]) {
+ drRegion = kTRUE;
+ }
+ if (cIdSensAm == cIdCurrent[1]) {
+ 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), according to standard coordinate system
+ cIdPath = gGeoManager->GetPath();
+ cIdSector[0] = cIdPath[21];
+ cIdSector[1] = cIdPath[22];
+ sector = atoi(cIdSector);
+
+ // The plane and chamber number
+ cIdChamber[0] = cIdCurrent[2];
+ cIdChamber[1] = cIdCurrent[3];
+ Int_t idChamber = (atoi(cIdChamber) % kNdetsec);
+ stack = ((Int_t) idChamber / kNlayer);
+ layer = ((Int_t) idChamber % kNlayer);
+
+ // The detector number
+ det = fGeometry->GetDetector(layer,stack,sector);
+
+ // Special hits only in the drift region
+ if ((drRegion) &&
+ (gMC->IsTrackEntering())) {
+
+ // Create a track reference at the entrance of each
+ // chamber that contains the momentum components of the particle
+ gMC->TrackMomentum(mom);
+ AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD);
+
+ // Create the hits from TR photons if electron/positron is
+ // entering the drift volume
+ if ((fTR) &&
+ (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) {
+ CreateTRhit(det);
+ }
+
+ }
+ else if ((amRegion) &&
+ (gMC->IsTrackExiting())) {
+
+ // Create a track reference at the exit of each
+ // chamber that contains the momentum components of the particle
+ gMC->TrackMomentum(mom);
+ AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD);
+
+ }
+
+ // Calculate the energy of the delta-electrons
+ eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
+ eDelta = TMath::Max(eDelta,0.0);
+
+ // Generate the electron cluster size
+ if (eDelta > 0.0) {
+
+ qTot = ((Int_t) (eDelta / fWion) + 1);
+
+ // Create a new dEdx hit
+ if (drRegion) {
+ AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
+ ,det
+ ,hits
+ ,qTot
+ ,gMC->TrackTime()*1.0e06
+ ,kTRUE);
+ }
+ else {
+ AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
+ ,det
+ ,hits
+ ,qTot
+ ,gMC->TrackTime()*1.0e06
+ ,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;
+ }
+ }
+ else {
+ // Electrons above 20 Mev/c are at the plateau
+ pp = kPrim * kPlateau;
+ }
+
+ if (pp > 0.0) {
+ do {
+ gMC->GetRandom()->RndmArray(1,random);
+ }
+ while ((random[0] == 1.0) ||
+ (random[0] == 0.0));
+ stepSize = - TMath::Log(random[0]) / pp;
+ gMC->SetMaxStep(stepSize);
+ }
+
+ }
+
+ }
+
+ }
- for (Int_t i = 0; i < 80; i++) printf("*");
- printf("\n");
+}
+
+//_____________________________________________________________________________
+void AliTRDv1::StepManagerFixedStep()
+{
+ //
+ // Slow simulator. Every charged track produces electron cluster as hits
+ // along its path across the drift volume. The step size is fixed in
+ // this version of the step manager.
+ //
+ // Works for Xe/CO2 as well as Ar/CO2
+ //
+
+ // PDG code electron
+ const Int_t kPdgElectron = 11;
+
+ Int_t layer = 0;
+ Int_t stack = 0;
+ Int_t sector = 0;
+ Int_t det = 0;
+ Int_t qTot;
+
+ Float_t hits[3];
+ Double_t eDep;
+
+ Bool_t drRegion = kFALSE;
+ Bool_t amRegion = kFALSE;
+
+ TString cIdPath;
+ Char_t cIdSector[3];
+ cIdSector[2] = 0;
+
+ TString cIdCurrent;
+ TString cIdSensDr = "J";
+ TString cIdSensAm = "K";
+ Char_t cIdChamber[3];
+ cIdChamber[2] = 0;
+
+ TLorentzVector pos;
+ TLorentzVector mom;
+
+ const Int_t kNlayer = AliTRDgeometry::Nlayer();
+ const Int_t kNstack = AliTRDgeometry::Nstack();
+ const Int_t kNdetsec = kNlayer * kNstack;
+
+ const Double_t kBig = 1.0e+12;
+ const Float_t kEkinMinStep = 1.0e-5; // Minimum energy for the step size adjustment
+
+ // Set the maximum step size to a very large number for all
+ // neutral particles and those outside the driftvolume
+ gMC->SetMaxStep(kBig);
+
+ // If not charged track or already stopped or disappeared, just return.
+ if ((!gMC->TrackCharge()) ||
+ gMC->IsTrackDisappeared()) {
+ return;
+ }
+
+ // Inside a sensitive volume?
+ cIdCurrent = gMC->CurrentVolName();
+
+ if (cIdSensDr == cIdCurrent[1]) {
+ drRegion = kTRUE;
+ }
+ if (cIdSensAm == cIdCurrent[1]) {
+ amRegion = kTRUE;
+ }
+
+ if ((!drRegion) &&
+ (!amRegion)) {
+ return;
+ }
+
+ // 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), according to standard coordinate system
+ cIdPath = gGeoManager->GetPath();
+ cIdSector[0] = cIdPath[21];
+ cIdSector[1] = cIdPath[22];
+ sector = atoi(cIdSector);
+
+ // The plane and chamber number
+ cIdChamber[0] = cIdCurrent[2];
+ cIdChamber[1] = cIdCurrent[3];
+ Int_t idChamber = (atoi(cIdChamber) % kNdetsec);
+ stack = ((Int_t) idChamber / kNlayer);
+ layer = ((Int_t) idChamber % kNlayer);
+
+ // The detector number
+ det = fGeometry->GetDetector(layer,stack,sector);
+
+ // 0: InFlight 1:Entering 2:Exiting
+ Int_t trkStat = 0;
+
+ // Special hits only in the drift region
+ if ((drRegion) &&
+ (gMC->IsTrackEntering())) {
+
+ // Create a track reference at the entrance of each
+ // chamber that contains the momentum components of the particle
+ gMC->TrackMomentum(mom);
+ AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD);
+ trkStat = 1;
+
+ // Create the hits from TR photons if electron/positron is
+ // entering the drift volume
+ if ((fTR) &&
+ (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) {
+ CreateTRhit(det);
+ }
+
+ }
+ else if ((amRegion) &&
+ (gMC->IsTrackExiting())) {
+
+ // Create a track reference at the exit of each
+ // chamber that contains the momentum components of the particle
+ gMC->TrackMomentum(mom);
+ AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD);
+ trkStat = 2;
+
+ }
- // Identifier of the sensitive volume (amplification region)
- fIdSens = gMC->VolId("UL06");
+ // Calculate the charge according to GEANT Edep
+ // Create a new dEdx hit
+ eDep = TMath::Max(gMC->Edep(),0.0) * 1.0e+09;
+ qTot = (Int_t) (eDep / fWion);
+ if ((qTot) ||
+ (trkStat)) {
+ AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
+ ,det
+ ,hits
+ ,qTot
+ ,gMC->TrackTime()*1.0e06
+ ,drRegion);
+ }
- // Identifier of the TRD-spaceframe volumina
- fIdSpace1 = gMC->VolId("B028");
- fIdSpace2 = gMC->VolId("B029");
- fIdSpace3 = gMC->VolId("B030");
+ // Set Maximum Step Size
+ // Produce only one hit if Ekin is below cutoff
+ if ((gMC->Etot() - gMC->TrackMass()) < kEkinMinStep) {
+ return;
+ }
+ gMC->SetMaxStep(fStepSize);
- // Identifier of the TRD-driftchambers
- fIdChamber1 = gMC->VolId("UCIO");
- fIdChamber2 = gMC->VolId("UCIM");
- fIdChamber3 = gMC->VolId("UCII");
+}
+
+//_____________________________________________________________________________
+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;
+
+ // Lower cutoff of the Bethe-Bloch-curve to limit step sizes
+ const Double_t kBgMin = 0.8;
+ const Double_t kBBMax = 6.83298;
+
+ if (bg > kBgMin) {
+ Double_t yy = bg / TMath::Sqrt(1.0 + bg*bg);
+ Double_t aa = TMath::Power(yy,kP4);
+ Double_t bb = TMath::Power((1.0/bg),kP5);
+ bb = TMath::Log(kP3 + bb);
+ return ((kP2 - aa - bb) * kP1 / aa);
+ }
+ else {
+ return kBBMax;
+ }
- printf("**************************************"
- " TRD "
- "**************************************\n");
}
//_____________________________________________________________________________
-void AliTRDv1::StepManager()
+Double_t AliTRDv1::BetheBlochGeant(Double_t bg)
{
//
- // 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.
+ // Return dN/dx (number of primary collisions per centimeter)
+ // for given beta*gamma factor.
+ //
+ // Implemented by K.Oyama according to GEANT 3 parametrization shown in
+ // A.Andronic's webpage: http://www-alice.gsi.de/trd/papers/dedx/dedx.html
+ // This must be used as a set with IntSpecGeant.
//
- Int_t vol[3];
- Int_t iIdSens, icSens;
- Int_t iIdSpace, icSpace;
- Int_t iIdChamber, icChamber;
+ Int_t i = 0;
- 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 };
+ Double_t arrG[20] = { 1.100000, 1.200000, 1.300000, 1.500000
+ , 1.800000, 2.000000, 2.500000, 3.000000
+ , 4.000000, 7.000000, 10.000000, 20.000000
+ , 40.000000, 70.000000, 100.000000, 300.000000
+ , 600.000000, 1000.000000, 3000.000000, 10000.000000 };
- Float_t hits[4];
+ Double_t arrNC[20] = { 75.009056, 45.508083, 35.299252, 27.116327
+ , 22.734999, 21.411915, 19.934095, 19.449375
+ , 19.344431, 20.185553, 21.027925, 22.912676
+ , 24.933352, 26.504053, 27.387468, 29.566597
+ , 30.353779, 30.787134, 31.129285, 31.157350 };
- TLorentzVector p;
- TClonesArray &lhits = *fHits;
+ // Betagamma to gamma
+ Double_t g = TMath::Sqrt(1.0 + bg*bg);
- // Writing out hits enabled?
- if (!(fHitsOn)) return;
+ // Find the index just before the point we need.
+ for (i = 0; i < 18; i++) {
+ if ((arrG[i] < g) &&
+ (arrG[i+1] > g)) {
+ break;
+ }
+ }
+
+ // Simple interpolation.
+ Double_t pp = ((arrNC[i+1] - arrNC[i]) / (arrG[i+1] - arrG[i]))
+ * (g - arrG[i]) + arrNC[i];
- // 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) {
+ return pp;
+
+}
- gMC->TrackPosition(p);
- for (Int_t i = 0; i < 3; i++) hits[i] = p[i];
- // No charge created
- hits[3] = 0;
+//_____________________________________________________________________________
+Double_t Ermilova(Double_t *x, Double_t *)
+{
+ //
+ // Calculates the delta-ray energy distribution according to Ermilova.
+ // Logarithmic scale !
+ //
- iIdSpace = gMC->CurrentVolOffID(4,icSpace );
- iIdChamber = gMC->CurrentVolOffID(1,icChamber);
+ Double_t energy;
+ Double_t dpos;
+ Double_t dnde;
- // 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];
+ Int_t pos1;
+ Int_t pos2;
- // 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;
+ const Int_t kNv = 31;
- // The plane number
- vol[2] = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6;
+ 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 };
- new(lhits[fNhits++]) AliTRDhit(fIshunt,gAlice->CurrentTrack(),vol,hits);
+ 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 = 0;
+ 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;
+
+}
+
+//_____________________________________________________________________________
+Double_t IntSpecGeant(Double_t *x, Double_t *)
+{
+ //
+ // Integrated spectrum from Geant3
+ //
+
+ const Int_t npts = 83;
+ Double_t arre[npts] = { 2.421257, 2.483278, 2.534301, 2.592230
+ , 2.672067, 2.813299, 3.015059, 3.216819
+ , 3.418579, 3.620338, 3.868209, 3.920198
+ , 3.978284, 4.063923, 4.186264, 4.308605
+ , 4.430946, 4.553288, 4.724261, 4.837736
+ , 4.999842, 5.161949, 5.324056, 5.486163
+ , 5.679688, 5.752998, 5.857728, 5.962457
+ , 6.067185, 6.171914, 6.315653, 6.393674
+ , 6.471694, 6.539689, 6.597658, 6.655627
+ , 6.710957, 6.763648, 6.816338, 6.876198
+ , 6.943227, 7.010257, 7.106285, 7.252151
+ , 7.460531, 7.668911, 7.877290, 8.085670
+ , 8.302979, 8.353585, 8.413120, 8.483500
+ , 8.541030, 8.592857, 8.668865, 8.820485
+ , 9.037086, 9.253686, 9.470286, 9.686887
+ , 9.930838, 9.994655, 10.085822, 10.176990
+ , 10.268158, 10.359325, 10.503614, 10.627565
+ , 10.804637, 10.981709, 11.158781, 11.335854
+ , 11.593397, 11.781165, 12.049404, 12.317644
+ , 12.585884, 12.854123, 14.278421, 16.975889
+ , 20.829416, 24.682943, 28.536469 };
+
+ Double_t arrdnde[npts] = { 10.960000, 10.960000, 10.359500, 9.811340
+ , 9.1601500, 8.206670, 6.919630, 5.655430
+ , 4.6221300, 3.777610, 3.019560, 2.591950
+ , 2.5414600, 2.712920, 3.327460, 4.928240
+ , 7.6185300, 10.966700, 12.225800, 8.094750
+ , 3.3586900, 1.553650, 1.209600, 1.263840
+ , 1.3241100, 1.312140, 1.255130, 1.165770
+ , 1.0594500, 0.945450, 0.813231, 0.699837
+ , 0.6235580, 2.260990, 2.968350, 2.240320
+ , 1.7988300, 1.553300, 1.432070, 1.535520
+ , 1.4429900, 1.247990, 1.050750, 0.829549
+ , 0.5900280, 0.395897, 0.268741, 0.185320
+ , 0.1292120, 0.103545, 0.0949525, 0.101535
+ , 0.1276380, 0.134216, 0.123816, 0.104557
+ , 0.0751843, 0.0521745, 0.0373546, 0.0275391
+ , 0.0204713, 0.0169234, 0.0154552, 0.0139194
+ , 0.0125592, 0.0113638, 0.0107354, 0.0102137
+ , 0.00845984, 0.00683338, 0.00556836, 0.00456874
+ , 0.0036227, 0.00285991, 0.00226664, 0.00172234
+ , 0.00131226, 0.00100284, 0.000465492, 7.26607e-05
+ , 3.63304e-06, 0.0000000, 0.0000000 };
+
+ Int_t i;
+ Double_t energy = x[0];
+
+ if (energy >= arre[npts-1]) {
+ return 0.0;
+ }
+
+ for (i = 0; i < npts; i++) {
+ if (energy < arre[i]) {
+ break;
}
+ }
+
+ if (i == 0) {
+ AliErrorGeneral("AliTRDv1::IntSpecGeant","Given energy value is too small or zero");
+ }
- }
+ return arrdnde[i];
}