1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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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 **************************************************************************/
18 /* History of cvs commits:
21 * Revision 1.30 2006/09/13 07:31:01 kharlov
22 * Effective C++ corrections (T.Pocheptsov)
24 * Revision 1.29 2005/05/28 14:19:05 schutz
25 * Compilation warnings fixed by T.P.
29 //_________________________________________________________________________
30 // Implementation of the PHOS manager class for fast simulations
31 // Tracks particles until the reach a grossly designed PHOS module
32 // Modify the particles property (momentum, energy, type) according to
33 // the PHOS response function. The result is called a virtual reconstructed
36 //*-- Author: Yves Schutz (SUBATECH)
38 // --- ROOT system ---
41 #include <TGeometry.h>
43 #include <TParticle.h>
44 #include "TClonesArray.h"
45 #include <TVirtualMC.h>
47 // --- Standard library ---
49 // --- AliRoot header files ---
50 #include "AliPHOSFastRecParticle.h"
51 #include "AliPHOSGeometry.h"
52 #include "AliPHOSLoader.h"
53 #include "AliPHOSvFast.h"
56 ClassImp(AliPHOSvFast)
58 AliPHOSvFast::AliPHOSvFast() :
74 // default ctor : initialize data member
77 //____________________________________________________________________________
78 AliPHOSvFast::AliPHOSvFast(const char *name, const char *title):
83 fFastRecParticles(new AliPHOSFastRecParticle::FastRecParticlesList("AliPHOSFastRecParticle", 100)),
86 fResPara1(0.030), // GeV
89 fPosParaA0(2.87), // mm
97 SetBigBox(0, GetGeometry()->GetOuterBoxSize(0) ) ;
98 SetBigBox(1, GetGeometry()->GetOuterBoxSize(3) + GetGeometry()->GetCPVBoxSize(1) ) ;
99 SetBigBox(2, GetGeometry()->GetOuterBoxSize(2) );
102 //____________________________________________________________________________
103 AliPHOSvFast::~AliPHOSvFast()
107 fFastRecParticles->Delete() ;
108 delete fFastRecParticles ;
109 fFastRecParticles = 0 ;
113 //____________________________________________________________________________
114 void AliPHOSvFast::AddRecParticle(const AliPHOSFastRecParticle & rp)
116 // Add a virtually reconstructed particle to the list
118 new( (*fFastRecParticles)[fNRecParticles] ) AliPHOSFastRecParticle(rp) ;
122 //____________________________________________________________________________
123 void AliPHOSvFast::CreateGeometry()
125 // Create the geometry for GEANT
127 AliPHOSvFast *phostmp = (AliPHOSvFast*)gAlice->GetModule("PHOS") ;
129 if ( phostmp == NULL ) {
131 fprintf(stderr, "PHOS detector not found!\n") ;
136 // Get pointer to the array containing media indeces
137 Int_t *idtmed = fIdtmed->GetArray() - 699 ;
140 bigbox[0] = GetBigBox(0) / 2.0 ;
141 bigbox[1] = GetBigBox(1) / 2.0 ;
142 bigbox[2] = GetBigBox(2) / 2.0 ;
144 gMC->Gsvolu("PHOS", "BOX ", idtmed[798], bigbox, 3) ;
146 // --- Position PHOS mdules in ALICE setup ---
149 Double_t const kRADDEG = 180.0 / TMath::Pi() ;
151 for( Int_t i = 1; i <= GetGeometry()->GetNModules(); i++ ) {
153 Float_t angle = GetGeometry()->GetPHOSAngle(i) ;
154 AliMatrix(idrotm[i-1], 90.0, angle, 90.0, 90.0+angle, 0.0, 0.0) ;
156 Float_t r = GetGeometry()->GetIPtoCrystalSurface() + GetBigBox(1) / 2.0 ;
158 Float_t xP1 = r * TMath::Sin( angle / kRADDEG ) ;
159 Float_t yP1 = -r * TMath::Cos( angle / kRADDEG ) ;
160 gMC->Gspos("PHOS", i, "ALIC", xP1, yP1, 0.0, idrotm[i-1], "ONLY") ;
167 //____________________________________________________________________________
168 void AliPHOSvFast::Init(void)
170 // Prints out an information message
175 for(i=0;i<35;i++) printf("*");
176 printf(" FAST PHOS_INIT ");
177 for(i=0;i<35;i++) printf("*");
180 // Here the PHOS initialisation code (if any!)
182 for(i=0;i<80;i++) printf("*");
187 //___________________________________________________________________________
188 Float_t AliPHOSvFast::GetBigBox(Int_t index) const
190 // Get the X, Y or Z dimension of the box describing a PHOS module
207 //___________________________________________________________________________
209 void AliPHOSvFast::MakeBranch(Option_t* opt)
211 // Create new branch in the current reconstructed Root Tree
212 AliDetector::MakeBranch(opt);
213 const char *cd = strstr(opt,"R");
215 if (fFastRecParticles && fLoader->TreeR() && cd) {
216 MakeBranchInTree(fLoader->TreeR(), GetName(), &fFastRecParticles, fBufferSize, 0);
219 //____________________________________________________________________________
221 Double_t AliPHOSvFast::MakeEnergy(Double_t energy)
223 // Smears the energy according to the energy dependent energy resolution.
224 // A gaussian distribution is assumed
226 Double_t sigma = SigmaE(energy) ;
227 return fRan.Gaus(energy, sigma) ;
229 //____________________________________________________________________________
231 TVector3 AliPHOSvFast::MakePosition(Double_t energy, TVector3 pos, Double_t theta, Double_t phi)
233 // Smears the impact position according to the energy dependent position resolution
234 // A gaussian position distribution is assumed
237 Double_t sigma = SigmaP( energy, theta*180./TMath::Pi() ) ;
238 Double_t x = fRan.Gaus( pos.X(), sigma ) ;
239 sigma = SigmaP( energy, phi*180./TMath::Pi() ) ;
240 Double_t z = fRan.Gaus( pos.Z(), sigma ) ;
241 Double_t y = pos.Y() ;
250 //____________________________________________________________________________
251 void AliPHOSvFast::MakeRecParticle(Int_t modid, TVector3 pos, AliPHOSFastRecParticle & rp)
253 // Modify the primary particle properties according
254 // 1. the response function of PHOS
255 // 2. the performance of the EMC+PPSD setup
257 Int_t type = MakeType( rp ) ;
261 // get the detected energy
263 TLorentzVector momentum ;
264 rp.Momentum(momentum) ;
265 Double_t kineticenergy = TMath::Sqrt( TMath::Power(momentum.E(), 2) - TMath::Power(rp.GetMass(), 2) ) ;
266 Double_t modifiedkineticenergy = MakeEnergy(kineticenergy ) ;
267 Double_t modifiedenergy = TMath::Sqrt( TMath::Power(modifiedkineticenergy, 2)
268 + TMath::Power( rp.GetMass(), 2) ) ;
270 // get the angle of incidence
272 Double_t incidencetheta = 90. * TMath::Pi() /180 - rp.Theta() ;
273 Double_t incidencephi = ( 270 + GetGeometry()->GetPHOSAngle(modid) ) * TMath::Pi() / 180. - rp.Phi() ;
275 // get the detected direction
277 TVector3 modifiedposition = MakePosition(kineticenergy, pos, incidencetheta, incidencephi) ;
278 modifiedposition *= modifiedkineticenergy / modifiedposition.Mag() ;
280 // Set the modified 4-momentum of the reconstructed particle
282 rp.SetMomentum(modifiedposition.X(), modifiedposition.Y(), modifiedposition.Z(), modifiedenergy) ;
286 //____________________________________________________________________________
287 Int_t AliPHOSvFast::MakeType(AliPHOSFastRecParticle & rp )
289 // Generate a particle type using the performance of the EMC+PPSD setup
291 Int_t rv = AliPHOSFastRecParticle::kUNDEFINED ;
292 Int_t charge = (Int_t)rp.GetPDG()->Charge() ;
295 if ( charge != 0 && ( TMath::Abs(rp.GetPdgCode()) != 11 ) )
298 test = rp.GetPdgCode() ;
300 Fatal("MakeType", "SHOULD NOT BE USED until values of probabilities are properly set ") ;
301 // NB: ALL VALUES SHOULD BE CHECKED !!!!
304 case 22: // it's a photon // NB: ALL VALUES SHOLD BE CHECKED !!!!
307 rv = AliPHOSFastRecParticle::kNEUTRALHAFAST ;
309 rv = AliPHOSFastRecParticle::kNEUTRALEMFAST ;
312 case 2112: // it's a neutron
315 rv = AliPHOSFastRecParticle::kNEUTRALHASLOW ;
317 rv = AliPHOSFastRecParticle::kNEUTRALEMSLOW ;
320 case -2112: // it's a anti-neutron
323 rv = AliPHOSFastRecParticle::kNEUTRALHASLOW ;
325 rv = AliPHOSFastRecParticle::kNEUTRALEMSLOW ;
328 case 11: // it's a electron
331 rv = AliPHOSFastRecParticle::kCHARGEDEMFAST ;
333 rv = AliPHOSFastRecParticle::kCHARGEDHAFAST ;
336 case -11: // it's a positon
339 rv = AliPHOSFastRecParticle::kCHARGEDEMFAST ;
341 rv = AliPHOSFastRecParticle::kCHARGEDHAFAST ;
344 case -1: // it's a charged
347 rv = AliPHOSFastRecParticle::kCHARGEDHAFAST ;
349 rv = AliPHOSFastRecParticle::kNEUTRALHAFAST ;
358 //___________________________________________________________________________
359 void AliPHOSvFast::ResetPoints()
361 // This overloads the method in AliDetector
363 ResetFastRecParticles() ;
366 //___________________________________________________________________________
367 void AliPHOSvFast::ResetFastRecParticles()
369 // Resets the list of virtual reconstructed particles
371 if (fFastRecParticles)
372 fFastRecParticles->Clear() ;
376 //___________________________________________________________________________
377 void AliPHOSvFast::SetBigBox(Int_t index, Float_t value)
379 // Set the size of the Box describing a PHOS module
395 //____________________________________________________________________________
396 Double_t AliPHOSvFast::SigmaE(Double_t energy)
398 // Calculates the energy dependent energy resolution
402 rv = TMath::Sqrt( TMath::Power(fResPara1/energy, 2)
403 + TMath::Power(fResPara2/TMath::Sqrt(energy), 2)
404 + TMath::Power(fResPara3, 2) ) ;
409 //____________________________________________________________________________
410 Double_t AliPHOSvFast::SigmaP(Double_t energy, Double_t incidence)
412 // Calculates the energy dependent position resolution
414 Double_t paraA = fPosParaA0 + fPosParaA1 * incidence ;
415 Double_t paraB = fPosParaB0 + fPosParaB1 * incidence + fPosParaB2 * incidence * incidence ;
417 return ( paraA / TMath::Sqrt(energy) + paraB ) * 0.1 ; // in cm
420 //____________________________________________________________________________
421 void AliPHOSvFast::StepManager(void)
423 // Only verifies if the particle reaches PHOS and stops the tracking
426 gMC->TrackPosition(lv) ;
427 TVector3 pos = lv.Vect() ;
429 gMC->CurrentVolID(modid);
431 Float_t energy = gMC->Etot() ; //Total energy of current track
433 //Calculating mass of current particle
434 TDatabasePDG * pdg = TDatabasePDG::Instance() ;
435 TParticlePDG * partPDG = pdg->GetParticle(gMC->TrackPid()) ;
436 Float_t mass = partPDG->Mass() ;
439 pos.SetMag(TMath::Sqrt(energy*energy-mass*mass)) ;
440 TLorentzVector pTrack(pos, energy) ;
442 TParticle * part = new TParticle(gMC->TrackPid(), 0,-1,-1,-1,-1, pTrack, lv) ;
444 AliPHOSFastRecParticle rp(*part) ;
446 // Adds the response of PHOS to the particle
447 MakeRecParticle(modid, pos, rp) ;
449 // add the `track' particle to the FastRecParticles list
455 // stop the track as soon PHOS is reached