[u/mrichter/AliRoot.git] / TRD / AliTRDtestG4.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

/* $Id$ */

////////////////////////////////////////////////////////////////////////////
//                                                                        //
//  Transition Radiation Detector version 1 -- slow simulator             //
//                                                                        //
////////////////////////////////////////////////////////////////////////////

#include <TLorentzVector.h>
#include <TMath.h>
#include <TRandom.h>
#include <TVirtualMC.h>
#include <TGeoManager.h>
#include <TGeoMatrix.h>
#include <TGeoPhysicalNode.h>

#include "AliTrackReference.h"
#include "AliMC.h"
#include "AliRun.h"
#include "AliGeomManager.h"

#include "AliTRDgeometry.h"
#include "AliTRDCommonParam.h"
#include "AliTRDsimTR.h"
#include "AliTRDtestG4.h"

ClassImp(AliTRDtestG4)
 
//_____________________________________________________________________________
AliTRDtestG4::AliTRDtestG4()
  :AliTRD()
  ,fTRon(kTRUE)
  ,fTR(NULL)
  ,fStepSize(0)
  ,fWion(0)
{
  //
  // Default constructor
  //

}

//_____________________________________________________________________________
AliTRDtestG4::AliTRDtestG4(const char *name, const char *title) 
  :AliTRD(name,title) 
  ,fTRon(kTRUE)
  ,fTR(NULL)
  ,fStepSize(0.1)
  ,fWion(0)
{
  //
  // Standard constructor for Transition Radiation Detector version 1
  //

  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);
  }

}

//_____________________________________________________________________________
AliTRDtestG4::~AliTRDtestG4()
{
  //
  // AliTRDtestG4 destructor
  //

  if (fTR) {
    delete fTR;
    fTR     = 0;
  }

}
 
//_____________________________________________________________________________
void AliTRDtestG4::AddAlignableVolumes() const
{
  //
  // 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.
  //

  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++) {

    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 AliTRDtestG4::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) {
    AliError("TRD needs FRAME to be present\n");
    return;
  }

  // Define the chambers
  AliTRD::CreateGeometry();

}

//_____________________________________________________________________________
void AliTRDtestG4::CreateMaterials()
{
  //
  // Create materials for the Transition Radiation Detector version 1
  //

  AliTRD::CreateMaterials();

}

//_____________________________________________________________________________
void AliTRDtestG4::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.
  //

  // 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
  TVirtualMC::GetMC()->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];
    TVirtualMC::GetMC()->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
          ,TVirtualMC::GetMC()->TrackTime()*1.0e06
          ,kTRUE);

  }

}

//_____________________________________________________________________________
void AliTRDtestG4::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();
  }

  AliDebug(1,"+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++");

}

//_____________________________________________________________________________
void AliTRDtestG4::StepManager()
{
  //
  // 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

  const Double_t kScaleG4     = 1.12;

  // Set the maximum step size to a very large number for all 
  // neutral particles and those outside the driftvolume
  if (!fPrimaryIonisation) TVirtualMC::GetMC()->SetMaxStep(kBig); 

  // If not charged track or already stopped or disappeared, just return.
  if ((!TVirtualMC::GetMC()->TrackCharge()) || 
        TVirtualMC::GetMC()->IsTrackDisappeared()) {
    return;
  }

  // Inside a sensitive volume?
  cIdCurrent = TVirtualMC::GetMC()->CurrentVolName();

  if (cIdSensDr == cIdCurrent[1]) {
    drRegion = kTRUE;
  }
  if (cIdSensAm == cIdCurrent[1]) {
    amRegion = kTRUE;
  }

  if ((!drRegion) && 
      (!amRegion)) {
    return;
  }

  // The hit coordinates and charge
  TVirtualMC::GetMC()->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) &&
           (TVirtualMC::GetMC()->IsTrackEntering())) {

    // Create a track reference at the entrance of each
    // chamber that contains the momentum components of the particle
    TVirtualMC::GetMC()->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)   &&
        (fTRon) &&
        (TMath::Abs(TVirtualMC::GetMC()->TrackPid()) == kPdgElectron)) {
      CreateTRhit(det);
    }

  }
  else if ((amRegion) && 
           (TVirtualMC::GetMC()->IsTrackExiting())) {

    // Create a track reference at the exit of each
    // chamber that contains the momentum components of the particle
    TVirtualMC::GetMC()->TrackMomentum(mom);
    AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD);
    trkStat = 2;

  }
  
  // Calculate the charge according to GEANT Edep
  // Create a new dEdx hit
  eDep = TMath::Max(TVirtualMC::GetMC()->Edep(),0.0) * 1.0e+09;
  eDep /= kScaleG4;
  qTot = (Int_t) (eDep / fWion);
  if ((qTot) ||
      (trkStat)) {
    AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
          ,det
          ,hits
          ,qTot
          ,TVirtualMC::GetMC()->TrackTime()*1.0e06
          ,drRegion);
  }

  // Set Maximum Step Size
  // Produce only one hit if Ekin is below cutoff
  if ((TVirtualMC::GetMC()->Etot() - TVirtualMC::GetMC()->TrackMass()) < kEkinMinStep) {
    return;
  }
  if (!fPrimaryIonisation) TVirtualMC::GetMC()->SetMaxStep(fStepSize);

}
Commit	Line	Data
d03ce825	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	/* $Id$ */
	17
	18	////////////////////////////////////////////////////////////////////////////
	19	// //
	20	// Transition Radiation Detector version 1 -- slow simulator //
	21	// //
	22	////////////////////////////////////////////////////////////////////////////
	23
	24	#include <TLorentzVector.h>
	25	#include <TMath.h>
	26	#include <TRandom.h>
	27	#include <TVirtualMC.h>
	28	#include <TGeoManager.h>
	29	#include <TGeoMatrix.h>
	30	#include <TGeoPhysicalNode.h>
	31
	32	#include "AliTrackReference.h"
	33	#include "AliMC.h"
	34	#include "AliRun.h"
	35	#include "AliGeomManager.h"
	36
	37	#include "AliTRDgeometry.h"
	38	#include "AliTRDCommonParam.h"
	39	#include "AliTRDsimTR.h"
	40	#include "AliTRDtestG4.h"
	41
	42	ClassImp(AliTRDtestG4)
	43
	44	//_____________________________________________________________________________
	45	AliTRDtestG4::AliTRDtestG4()
	46	:AliTRD()
	47	,fTRon(kTRUE)
	48	,fTR(NULL)
	49	,fStepSize(0)
	50	,fWion(0)
	51	{
	52	//
	53	// Default constructor
	54	//
	55
	56	}
	57
	58	//_____________________________________________________________________________
	59	AliTRDtestG4::AliTRDtestG4(const char name, const char title)
	60	:AliTRD(name,title)
	61	,fTRon(kTRUE)
	62	,fTR(NULL)
	63	,fStepSize(0.1)
	64	,fWion(0)
65	{
66	//
67	// Standard constructor for Transition Radiation Detector version 1
68	//
69
70	SetBufferSize(128000);
71
72	if (AliTRDCommonParam::Instance()->IsXenon()) {
73	fWion = 23.53; // Ionization energy XeCO2 (85/15)
74	}
75	else if (AliTRDCommonParam::Instance()->IsArgon()) {
76	fWion = 27.21; // Ionization energy ArCO2 (82/18)
77	}
78	else {
79	AliFatal("Wrong gas mixture");
80	exit(1);
81	}
82
83	}
84
85	//_____________________________________________________________________________
86	AliTRDtestG4::~AliTRDtestG4()
87	{
88	//
89	// AliTRDtestG4 destructor
90	//
91
92	if (fTR) {
93	delete fTR;
94	fTR = 0;
95	}
96
97	}
98
99	//_____________________________________________________________________________
100	void AliTRDtestG4::AddAlignableVolumes() const
101	{
102	//
103	// Create entries for alignable volumes associating the symbolic volume
104	// name with the corresponding volume path. Needs to be syncronized with
105	// eventual changes in the geometry.
106	//
107
108	TString volPath;
109	TString symName;
110
111	TString vpStr = "ALIC_1/B077_1/BSEGMO";
112	TString vpApp1 = "_1/BTRD";
113	TString vpApp2 = "_1";
114	TString vpApp3a = "/UTR1_1/UTS1_1/UTI1_1/UT";
115	TString vpApp3b = "/UTR2_1/UTS2_1/UTI2_1/UT";
116	TString vpApp3c = "/UTR3_1/UTS3_1/UTI3_1/UT";
117
118	TString snStr = "TRD/sm";
119	TString snApp1 = "/st";
120	TString snApp2 = "/pl";
121
122	//
123	// The super modules
124	// The symbolic names are: TRD/sm00
125	// ...
126	// TRD/sm17
127	//
128	for (Int_t isector = 0; isector < AliTRDgeometry::Nsector(); isector++) {
129
130	volPath = vpStr;
131	volPath += isector;
132	volPath += vpApp1;
133	volPath += isector;
134	volPath += vpApp2;
135
136	symName = snStr;
137	symName += Form("%02d",isector);
138
139	gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data());
140
141	}
142
143	//
144	// The readout chambers
145	// The symbolic names are: TRD/sm00/st0/pl0
146	// ...
147	// TRD/sm17/st4/pl5
148	//
149	AliGeomManager::ELayerID idTRD1 = AliGeomManager::kTRD1;
150	Int_t layer, modUID;
151
152	for (Int_t isector = 0; isector < AliTRDgeometry::Nsector(); isector++) {
153
154	if (fGeometry->GetSMstatus(isector) == 0) continue;
155
156	for (Int_t istack = 0; istack < AliTRDgeometry::Nstack(); istack++) {
157	for (Int_t ilayer = 0; ilayer < AliTRDgeometry::Nlayer(); ilayer++) {
158
159	layer = idTRD1 + ilayer;
160	modUID = AliGeomManager::LayerToVolUIDSafe(layer,isector*5+istack);
161
162	Int_t idet = AliTRDgeometry::GetDetectorSec(ilayer,istack);
163
164	volPath = vpStr;
165	volPath += isector;
166	volPath += vpApp1;
167	volPath += isector;
168	volPath += vpApp2;
169	switch (isector) {
170	case 13:
171	case 14:
172	case 15:
173	if (istack == 2) {
174	continue;
175	}
176	volPath += vpApp3c;
177	break;
178	case 11:
179	case 12:
180	volPath += vpApp3b;
181	break;
182	default:
183	volPath += vpApp3a;
184	};
185	volPath += Form("%02d",idet);
186	volPath += vpApp2;
187
188	symName = snStr;
189	symName += Form("%02d",isector);
190	symName += snApp1;
191	symName += istack;
192	symName += snApp2;
193	symName += ilayer;
194
195	TGeoPNEntry *alignableEntry =
196	gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data(),modUID);
197
198	// Add the tracking to local matrix following the TPC example
199	if (alignableEntry) {
200	TGeoHMatrix *globMatrix = alignableEntry->GetGlobalOrig();
201	Double_t sectorAngle = 20.0 * (isector % 18) + 10.0;
202	TGeoHMatrix *t2lMatrix = new TGeoHMatrix();
203	t2lMatrix->RotateZ(sectorAngle);
204	t2lMatrix->MultiplyLeft(&(globMatrix->Inverse()));
205	alignableEntry->SetMatrix(t2lMatrix);
206	}
207	else {
208	AliError(Form("Alignable entry %s is not valid!",symName.Data()));
209	}
210
211	}
212	}
213	}
214
215	}
216
217	//_____________________________________________________________________________
218	void AliTRDtestG4::CreateGeometry()
219	{
220	//
221	// Create the GEANT geometry for the Transition Radiation Detector - Version 1
222	// This version covers the full azimuth.
223	//
224
225	// Check that FRAME is there otherwise we have no place where to put the TRD
226	AliModule* frame = gAlice->GetModule("FRAME");
227	if (!frame) {
228	AliError("TRD needs FRAME to be present\n");
229	return;
230	}
231
232	// Define the chambers
233	AliTRD::CreateGeometry();
234
235	}
236
237	//_____________________________________________________________________________
238	void AliTRDtestG4::CreateMaterials()
239	{
240	//
241	// Create materials for the Transition Radiation Detector version 1
242	//
243
244	AliTRD::CreateMaterials();
245
246	}
247
248	//_____________________________________________________________________________
249	void AliTRDtestG4::CreateTRhit(Int_t det)
250	{
251	//
252	// Creates an electron cluster from a TR photon.
253	// The photon is assumed to be created a the end of the radiator. The
254	// distance after which it deposits its energy takes into account the
255	// absorbtion of the entrance window and of the gas mixture in drift
256	// volume.
257	//
258
259	// Maximum number of TR photons per track
260	const Int_t kNTR = 50;
261
262	TLorentzVector mom;
263	TLorentzVector pos;
264
265	Float_t eTR[kNTR];
266	Int_t nTR;
267
268	// Create TR photons
269	TVirtualMC::GetMC()->TrackMomentum(mom);
270	Float_t pTot = mom.Rho();
271	fTR->CreatePhotons(11,pTot,nTR,eTR);
272	if (nTR > kNTR) {
273	AliFatal(Form("Boundary error: nTR = %d, kNTR = %d",nTR,kNTR));
274	}
275
276	// Loop through the TR photons
277	for (Int_t iTR = 0; iTR < nTR; iTR++) {
278
279	Float_t energyMeV = eTR[iTR] * 0.001;
280	Float_t energyeV = eTR[iTR] * 1000.0;
281	Float_t absLength = 0.0;
282	Float_t sigma = 0.0;
283
284	// Take the absorbtion in the entrance window into account
285	Double_t muMy = fTR->GetMuMy(energyMeV);
286	sigma = muMy * fFoilDensity;
287	if (sigma > 0.0) {
288	absLength = gRandom->Exp(1.0/sigma);
289	if (absLength < AliTRDgeometry::MyThick()) {
290	continue;
291	}
292	}
293	else {
294	continue;
295	}
296
297	// The absorbtion cross sections in the drift gas
298	// Gas-mixture (Xe/CO2)
299	Double_t muNo = 0.0;
300	if (AliTRDCommonParam::Instance()->IsXenon()) {
301	muNo = fTR->GetMuXe(energyMeV);
302	}
303	else if (AliTRDCommonParam::Instance()->IsArgon()) {
304	muNo = fTR->GetMuAr(energyMeV);
305	}
306	Double_t muCO = fTR->GetMuCO(energyMeV);
307	sigma = (fGasNobleFraction * muNo + (1.0 - fGasNobleFraction) * muCO)
308	* fGasDensity
309	* fTR->GetTemp();
310
311	// The distance after which the energy of the TR photon
312	// is deposited.
313	if (sigma > 0.0) {
314	absLength = gRandom->Exp(1.0/sigma);
315	if (absLength > (AliTRDgeometry::DrThick()
316	+ AliTRDgeometry::AmThick())) {
317	continue;
318	}
319	}
320	else {
321	continue;
322	}
323
324	// The position of the absorbtion
325	Float_t posHit[3];
326	TVirtualMC::GetMC()->TrackPosition(pos);
327	posHit[0] = pos[0] + mom[0] / pTot * absLength;
328	posHit[1] = pos[1] + mom[1] / pTot * absLength;
329	posHit[2] = pos[2] + mom[2] / pTot * absLength;
330
331	// Create the charge
332	Int_t q = ((Int_t) (energyeV / fWion));
333
334	// Add the hit to the array. TR photon hits are marked
335	// by negative charge
336	AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
337	,det
338	,posHit
339	,-q
340	,TVirtualMC::GetMC()->TrackTime()*1.0e06
341	,kTRUE);
342
343	}
344
345	}
346
347	//_____________________________________________________________________________
348	void AliTRDtestG4::Init()
349	{
350	//
351	// Initialise Transition Radiation Detector after geometry has been built.
352	//
353
354	AliTRD::Init();
355
356	AliDebug(1,"Slow simulator\n");
357
358	// Switch on TR simulation as default
359	if (!fTRon) {
360	AliInfo("TR simulation off");
361	}
362	else {
363	fTR = new AliTRDsimTR();
364	}
365
366	AliDebug(1,"+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
367
368	}
369
370	//_____________________________________________________________________________
371	void AliTRDtestG4::StepManager()
372	{
373	//
374	// Slow simulator. Every charged track produces electron cluster as hits
375	// along its path across the drift volume. The step size is fixed in
376	// this version of the step manager.
377	//
378	// Works for Xe/CO2 as well as Ar/CO2
379	//
380
381	// PDG code electron
382	const Int_t kPdgElectron = 11;
383
384	Int_t layer = 0;
385	Int_t stack = 0;
386	Int_t sector = 0;
387	Int_t det = 0;
388	Int_t qTot;
389
390	Float_t hits[3];
391	Double_t eDep;
392
393	Bool_t drRegion = kFALSE;
394	Bool_t amRegion = kFALSE;
395
396	TString cIdPath;
397	Char_t cIdSector[3];
398	cIdSector[2] = 0;
399
400	TString cIdCurrent;
401	TString cIdSensDr = "J";
402	TString cIdSensAm = "K";
403	Char_t cIdChamber[3];
404	cIdChamber[2] = 0;
405
406	TLorentzVector pos;
407	TLorentzVector mom;
408
409	const Int_t kNlayer = AliTRDgeometry::Nlayer();
410	const Int_t kNstack = AliTRDgeometry::Nstack();
411	const Int_t kNdetsec = kNlayer * kNstack;
412
413	const Double_t kBig = 1.0e+12;
414	const Float_t kEkinMinStep = 1.0e-5; // Minimum energy for the step size adjustment
415
416	const Double_t kScaleG4 = 1.12;
417
418	// Set the maximum step size to a very large number for all
419	// neutral particles and those outside the driftvolume
420	if (!fPrimaryIonisation) TVirtualMC::GetMC()->SetMaxStep(kBig);
421
422	// If not charged track or already stopped or disappeared, just return.
423	if ((!TVirtualMC::GetMC()->TrackCharge()) \|\|
424	TVirtualMC::GetMC()->IsTrackDisappeared()) {
425	return;
426	}
427
428	// Inside a sensitive volume?
429	cIdCurrent = TVirtualMC::GetMC()->CurrentVolName();
430
431	if (cIdSensDr == cIdCurrent[1]) {
432	drRegion = kTRUE;
433	}
434	if (cIdSensAm == cIdCurrent[1]) {
435	amRegion = kTRUE;
436	}
437
438	if ((!drRegion) &&
439	(!amRegion)) {
440	return;
441	}
442
443	// The hit coordinates and charge
444	TVirtualMC::GetMC()->TrackPosition(pos);
445	hits[0] = pos[0];
446	hits[1] = pos[1];
447	hits[2] = pos[2];
448
449	// The sector number (0 - 17), according to standard coordinate system
450	cIdPath = gGeoManager->GetPath();
451	cIdSector[0] = cIdPath[21];
452	cIdSector[1] = cIdPath[22];
453	sector = atoi(cIdSector);
454
455	// The plane and chamber number
456	cIdChamber[0] = cIdCurrent[2];
457	cIdChamber[1] = cIdCurrent[3];
458	Int_t idChamber = (atoi(cIdChamber) % kNdetsec);
459	stack = ((Int_t) idChamber / kNlayer);
460	layer = ((Int_t) idChamber % kNlayer);
461
462	// The detector number
463	det = fGeometry->GetDetector(layer,stack,sector);
464
465	// 0: InFlight 1:Entering 2:Exiting
466	Int_t trkStat = 0;
467
468	// Special hits only in the drift region
469	if ((drRegion) &&
470	(TVirtualMC::GetMC()->IsTrackEntering())) {
471
472	// Create a track reference at the entrance of each
473	// chamber that contains the momentum components of the particle
474	TVirtualMC::GetMC()->TrackMomentum(mom);
475	AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD);
476	trkStat = 1;
477
478	// Create the hits from TR photons if electron/positron is
479	// entering the drift volume
480	if ((fTR) &&
481	(fTRon) &&
482	(TMath::Abs(TVirtualMC::GetMC()->TrackPid()) == kPdgElectron)) {
483	CreateTRhit(det);
484	}
485
486	}
487	else if ((amRegion) &&
488	(TVirtualMC::GetMC()->IsTrackExiting())) {
489
490	// Create a track reference at the exit of each
491	// chamber that contains the momentum components of the particle
492	TVirtualMC::GetMC()->TrackMomentum(mom);
493	AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD);
494	trkStat = 2;
495
496	}
497
498	// Calculate the charge according to GEANT Edep
499	// Create a new dEdx hit
500	eDep = TMath::Max(TVirtualMC::GetMC()->Edep(),0.0) * 1.0e+09;
501	eDep /= kScaleG4;
502	qTot = (Int_t) (eDep / fWion);
503	if ((qTot) \|\|
504	(trkStat)) {
505	AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
506	,det
507	,hits
508	,qTot
509	,TVirtualMC::GetMC()->TrackTime()*1.0e06
510	,drRegion);
511	}
512
513	// Set Maximum Step Size
514	// Produce only one hit if Ekin is below cutoff
515	if ((TVirtualMC::GetMC()->Etot() - TVirtualMC::GetMC()->TrackMass()) < kEkinMinStep) {
516	return;
517	}
518	if (!fPrimaryIonisation) TVirtualMC::GetMC()->SetMaxStep(fStepSize);
519
520	}