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. *
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 **************************************************************************/
18 //_________________________________________________________________________
19 // Implementation of the PHOS manager class for fast simulations
20 // Tracks particles until the reach a grossly designed PHOS module
21 // Modify the particles property (momentum, energy, type) according to
22 // the PHOS response function. The result is called a virtual reconstructed
25 //*-- Author: Yves Schutz (SUBATECH)
27 // --- ROOT system ---
31 #include "TParticle.h"
33 #include "TGeometry.h"
36 // --- Standard library ---
40 // --- AliRoot header files ---
41 #include "AliPHOSFastRecParticle.h"
42 #include "AliPHOSGeometry.h"
43 #include "AliPHOSv4.h"
44 #include "AliPHOSGetter.h"
51 //____________________________________________________________________________
52 AliPHOSv4::AliPHOSv4() : AliPHOS()
54 // default ctor : initialize data member
58 fFastRecParticles = 0 ;
72 //____________________________________________________________________________
73 AliPHOSv4::AliPHOSv4(const char *name, const char *title):
79 // create the geometry parameters object
80 // and post it to a folder (Post retrieves the correct geometry)
81 AliPHOSGetter::GetInstance(gDirectory->GetName(), 0)->PostGeometry() ;
83 SetBigBox(0, GetGeometry()->GetOuterBoxSize(0) ) ;
84 SetBigBox(1, GetGeometry()->GetOuterBoxSize(1) + GetGeometry()->GetCPVBoxSize(1) ) ;
85 SetBigBox(2, GetGeometry()->GetOuterBoxSize(0) );
88 fFastRecParticles = new AliPHOSFastRecParticle::FastRecParticlesList("AliPHOSFastRecParticle", 100) ;
90 fResPara1 = 0.030 ; // GeV
94 fPosParaA0 = 2.87 ; // mm
95 fPosParaA1 = -0.0975 ;
98 fPosParaB2 = 0.00619 ;
101 //____________________________________________________________________________
102 AliPHOSv4::~AliPHOSv4()
106 fFastRecParticles->Delete() ;
107 delete fFastRecParticles ;
108 fFastRecParticles = 0 ;
112 //____________________________________________________________________________
113 void AliPHOSv4::AddRecParticle(const AliPHOSFastRecParticle & rp)
115 // Add a virtually reconstructed particle to the list
117 new( (*fFastRecParticles)[fNRecParticles] ) AliPHOSFastRecParticle(rp) ;
121 //____________________________________________________________________________
122 void AliPHOSv4::BuildGeometry()
124 // Build the PHOS geometry for the ROOT display
128 PHOS FAST in ALICE displayed by root
133 <IMG Align=BOTTOM ALT="Fast All Views" SRC="../images/AliPHOSv4AllViews.gif">
135 <H4> Front View </H4>
138 <IMG Align=BOTTOM ALT="Fast Front View" SRC="../images/AliPHOSv4FrontView.gif">
143 const Int_t kColorPHOS = kRed ;
145 Double_t const kRADDEG = 180.0 / kPI ;
147 new TBRIK( "BigBox", "PHOS box", "void", GetBigBox(0)/2,
151 // position PHOS into ALICE
153 Float_t r = GetGeometry()->GetIPtoCrystalSurface() + GetBigBox(1) / 2.0 ;
155 Float_t pphi = TMath::ATan( GetBigBox(0) / ( 2.0 * GetGeometry()->GetIPtoCrystalSurface() ) ) ;
157 TNode * top = gAlice->GetGeometry()->GetNode("alice") ;
159 char * nodename = new char[20] ;
160 char * rotname = new char[20] ;
162 for( Int_t i = 1; i <= GetGeometry()->GetNModules(); i++ ) {
163 Float_t angle = pphi * 2 * ( i - GetGeometry()->GetNModules() / 2.0 - 0.5 ) ;
164 sprintf(rotname, "%s%d", "rot", number++) ;
165 new TRotMatrix(rotname, rotname, 90, angle, 90, 90 + angle, 0, 0);
167 sprintf(nodename,"%s%d", "Module", i) ;
168 Float_t x = r * TMath::Sin( angle / kRADDEG ) ;
169 Float_t y = -r * TMath::Cos( angle / kRADDEG ) ;
170 TNode * bigboxnode = new TNode(nodename, nodename, "BigBox", x, y, 0, rotname ) ;
171 bigboxnode->SetLineColor(kColorPHOS) ;
172 fNodes->Add(bigboxnode) ;
178 //____________________________________________________________________________
179 void AliPHOSv4::CreateGeometry()
181 // Create the geometry for GEANT
183 AliPHOSv4 *phostmp = dynamic_cast<AliPHOSv4*>(gAlice->GetModule("PHOS")) ;
185 if ( phostmp == NULL ) {
187 fprintf(stderr, "PHOS detector not found!\n") ;
192 // Get pointer to the array containing media indeces
193 Int_t *idtmed = fIdtmed->GetArray() - 699 ;
196 bigbox[0] = GetBigBox(0) / 2.0 ;
197 bigbox[1] = GetBigBox(1) / 2.0 ;
198 bigbox[2] = GetBigBox(2) / 2.0 ;
200 gMC->Gsvolu("PHOS", "BOX ", idtmed[798], bigbox, 3) ;
202 // --- Position PHOS mdules in ALICE setup ---
205 Double_t const kRADDEG = 180.0 / kPI ;
207 for( Int_t i = 1; i <= GetGeometry()->GetNModules(); i++ ) {
209 Float_t angle = GetGeometry()->GetPHOSAngle(i) ;
210 AliMatrix(idrotm[i-1], 90.0, angle, 90.0, 90.0+angle, 0.0, 0.0) ;
212 Float_t r = GetGeometry()->GetIPtoCrystalSurface() + GetBigBox(1) / 2.0 ;
214 Float_t xP1 = r * TMath::Sin( angle / kRADDEG ) ;
215 Float_t yP1 = -r * TMath::Cos( angle / kRADDEG ) ;
216 gMC->Gspos("PHOS", i, "ALIC", xP1, yP1, 0.0, idrotm[i-1], "ONLY") ;
223 //____________________________________________________________________________
224 void AliPHOSv4::Init(void)
226 // Prints out an information message
231 for(i=0;i<35;i++) printf("*");
232 printf(" FAST PHOS_INIT ");
233 for(i=0;i<35;i++) printf("*");
236 // Here the PHOS initialisation code (if any!)
238 for(i=0;i<80;i++) printf("*");
243 //___________________________________________________________________________
244 Float_t AliPHOSv4::GetBigBox(Int_t index) const
246 // Get the X, Y or Z dimension of the box describing a PHOS module
264 //___________________________________________________________________________
265 void AliPHOSv4::MakeBranch(Option_t* opt, const char *file)
267 // Create new branch in the current reconstructed Root Tree
269 AliDetector::MakeBranch(opt,file) ;
272 sprintf(branchname,"%s",GetName());
273 const char *cd = strstr(opt,"R");
275 if (fFastRecParticles && gAlice->TreeR() && cd) {
276 MakeBranchInTree(gAlice->TreeR(),
277 branchname, &fFastRecParticles, fBufferSize, file);
281 //____________________________________________________________________________
282 Double_t AliPHOSv4::MakeEnergy(const Double_t energy)
284 // Smears the energy according to the energy dependent energy resolution.
285 // A gaussian distribution is assumed
287 Double_t sigma = SigmaE(energy) ;
288 return fRan.Gaus(energy, sigma) ;
291 //____________________________________________________________________________
292 TVector3 AliPHOSv4::MakePosition(const Double_t energy, const TVector3 pos, const Double_t theta, const Double_t phi)
294 // Smears the impact position according to the energy dependent position resolution
295 // A gaussian position distribution is assumed
298 Double_t sigma = SigmaP( energy, theta*180./TMath::Pi() ) ;
299 Double_t x = fRan.Gaus( pos.X(), sigma ) ;
300 sigma = SigmaP( energy, phi*180./TMath::Pi() ) ;
301 Double_t z = fRan.Gaus( pos.Z(), sigma ) ;
302 Double_t y = pos.Y() ;
311 //____________________________________________________________________________
312 void AliPHOSv4::MakeRecParticle(const Int_t modid, const TVector3 pos, AliPHOSFastRecParticle & rp)
314 // Modify the primary particle properties according
315 // 1. the response function of PHOS
316 // 2. the performance of the EMC+PPSD setup
318 Int_t type = MakeType( rp ) ;
322 // get the detected energy
324 TLorentzVector momentum ;
325 rp.Momentum(momentum) ;
326 Double_t kineticenergy = TMath::Sqrt( TMath::Power(momentum.E(), 2) - TMath::Power(rp.GetMass(), 2) ) ;
327 Double_t modifiedkineticenergy = MakeEnergy(kineticenergy ) ;
328 Double_t modifiedenergy = TMath::Sqrt( TMath::Power(modifiedkineticenergy, 2)
329 + TMath::Power( rp.GetMass(), 2) ) ;
331 // get the angle of incidence
333 Double_t incidencetheta = 90. * TMath::Pi() /180 - rp.Theta() ;
334 Double_t incidencephi = ( 270 + GetGeometry()->GetPHOSAngle(modid) ) * TMath::Pi() / 180. - rp.Phi() ;
336 // get the detected direction
338 TVector3 modifiedposition = MakePosition(kineticenergy, pos, incidencetheta, incidencephi) ;
339 modifiedposition *= modifiedkineticenergy / modifiedposition.Mag() ;
341 // Set the modified 4-momentum of the reconstructed particle
343 rp.SetMomentum(modifiedposition.X(), modifiedposition.Y(), modifiedposition.Z(), modifiedenergy) ;
347 //____________________________________________________________________________
348 Int_t AliPHOSv4::MakeType(AliPHOSFastRecParticle & rp )
350 // Generate a particle type using the performance of the EMC+PPSD setup
352 Int_t rv = AliPHOSFastRecParticle::kUNDEFINED ;
353 Int_t charge = (Int_t)rp.GetPDG()->Charge() ;
356 if ( charge != 0 && ( TMath::Abs(rp.GetPdgCode()) != 11 ) )
359 test = rp.GetPdgCode() ;
363 case 22: // it's a photon
365 if ( ran <= 0.5 ) // 50 %
366 rv = AliPHOSFastRecParticle::kGAMMA ;
370 rv = AliPHOSFastRecParticle::kNEUTRALEM ;
372 rv = AliPHOSFastRecParticle::kNEUTRALHA ;
376 case 2112: // it's a neutron
379 rv = AliPHOSFastRecParticle::kNEUTRALHA ;
381 rv = AliPHOSFastRecParticle::kNEUTRALEM ;
384 case -2112: // it's a anti-neutron
387 rv = AliPHOSFastRecParticle::kNEUTRALHA ;
389 rv = AliPHOSFastRecParticle::kNEUTRALEM ;
392 case 11: // it's a electron
395 rv = AliPHOSFastRecParticle::kELECTRON ;
397 rv = AliPHOSFastRecParticle::kCHARGEDHA ;
400 case -11: // it's a positon
403 rv = AliPHOSFastRecParticle::kELECTRON ;
405 rv = AliPHOSFastRecParticle::kCHARGEDHA ;
408 case -1: // it's a charged
411 rv = AliPHOSFastRecParticle::kCHARGEDHA ;
413 rv = AliPHOSFastRecParticle::kGAMMA ;
422 //___________________________________________________________________________
423 void AliPHOSv4::ResetPoints()
425 // This overloads the method in AliDetector
427 ResetFastRecParticles() ;
430 //___________________________________________________________________________
431 void AliPHOSv4::ResetFastRecParticles()
433 // Resets the list of virtual reconstructed particles
435 if (fFastRecParticles)
436 fFastRecParticles->Clear() ;
440 //___________________________________________________________________________
441 void AliPHOSv4::SetBigBox(Int_t index, Float_t value)
443 // Set the size of the Box describing a PHOS module
459 //____________________________________________________________________________
460 Double_t AliPHOSv4::SigmaE(Double_t energy)
462 // Calculates the energy dependent energy resolution
466 rv = TMath::Sqrt( TMath::Power(fResPara1/energy, 2)
467 + TMath::Power(fResPara2/TMath::Sqrt(energy), 2)
468 + TMath::Power(fResPara3, 2) ) ;
473 //____________________________________________________________________________
474 Double_t AliPHOSv4::SigmaP(Double_t energy, Double_t incidence)
476 // Calculates the energy dependent position resolution
478 Double_t paraA = fPosParaA0 + fPosParaA1 * incidence ;
479 Double_t paraB = fPosParaB0 + fPosParaB1 * incidence + fPosParaB2 * incidence * incidence ;
481 return ( paraA / TMath::Sqrt(energy) + paraB ) * 0.1 ; // in cm
484 //____________________________________________________________________________
485 void AliPHOSv4::StepManager(void)
487 // Only verifies if the particle reaches PHOS and stops the tracking
489 Int_t primary = gAlice->GetPrimary( gAlice->CurrentTrack() );
492 gMC->TrackPosition(lv) ;
493 TVector3 pos = lv.Vect() ;
495 gMC->CurrentVolID(modid);
497 Float_t energy = gMC->Etot() ; //Total energy of current track
499 //Calculating mass of current particle
500 TDatabasePDG * pdg = TDatabasePDG::Instance() ;
501 TParticlePDG * partPDG = pdg->GetParticle(gMC->TrackPid()) ;
502 Float_t mass = partPDG->Mass() ;
505 pos.SetMag(TMath::Sqrt(energy*energy-mass*mass)) ;
506 TLorentzVector pTrack(pos, energy) ;
508 TParticle * part = new TParticle(gMC->TrackPid(), 0,-1,-1,-1,-1, pTrack, lv) ;
510 AliPHOSFastRecParticle rp(*part) ;
511 rp.SetPrimary(primary) ;
513 // Adds the response of PHOS to the particle
514 MakeRecParticle(modid, pos, rp) ;
516 // add the `track' particle to the FastRecParticles list
522 // stop the track as soon PHOS is reached