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 #include "AliMUONTriggerTrackToTrackerClusters.h"
20 ///\class AliMUONTriggerTrackToTrackerClusters
22 /// Class to convert trigger tracks into "fake" clusters in stations 4 and 5
24 /// Only intent is to be able to reconstruct data where stations 4 and 5 were
25 /// not functionning, typically early cosmic runs
27 ///\author Laurent Aphecetche, Subatech
29 #include "AliCodeTimer.h"
31 #include "AliMUONConstants.h"
32 #include "AliMUONGeometryTransformer.h"
33 #include "AliMUONTrack.h"
34 #include "AliMUONTrackExtrap.h"
35 #include "AliMUONTriggerTrack.h"
36 #include "AliMUONVCluster.h"
37 #include "AliMUONVClusterStore.h"
38 #include "AliMUONVTriggerTrackStore.h"
39 #include "AliMUONTrackParam.h"
40 #include "AliMpArea.h"
41 #include "AliMpDEManager.h"
45 ClassImp(AliMUONTriggerTrackToTrackerClusters)
48 //_____________________________________________________________________________
49 AliMUONTriggerTrackToTrackerClusters::AliMUONTriggerTrackToTrackerClusters(const AliMUONGeometryTransformer& transformer,
50 AliMUONVTriggerTrackStore* trackStore)
51 : TObject(), fkTransformer(transformer), fTriggerTrackStore(trackStore)
53 /// ctor. We do not take ownership of the trigger track store.
56 //_____________________________________________________________________________
57 AliMUONTriggerTrackToTrackerClusters::~AliMUONTriggerTrackToTrackerClusters()
62 //_____________________________________________________________________________
64 AliMUONTriggerTrackToTrackerClusters::DetElemId(Int_t chamber, Double_t x, Double_t y,
65 Double_t ex, Double_t ey,
68 /// Find in which detection element (x,y) (global) position is.
72 AliMpArea a(x, y, ex, ey);
76 while ( !it.IsDone() )
78 Int_t detElemId = it.CurrentDEId();
80 AliMpArea* area = fkTransformer.GetDEArea(detElemId);
82 if ( area->Overlap(a) )
84 // get z of the center of that DE.
85 Double_t dummyx, dummyy;
86 fkTransformer.Local2Global(detElemId,0,0,0,dummyx,dummyy,z);
95 //_____________________________________________________________________________
97 AliMUONTriggerTrackToTrackerClusters::GenerateClusters(Int_t iChamber,
98 AliMUONVClusterStore& clusterStore) const
100 /// Generate clusters in given chamber
101 /// Return the number of clusters added to the clusterStore
103 AliCodeTimerAuto(Form("Chamber %d",iChamber),0);
105 TIter next(fTriggerTrackStore->CreateIterator());
107 AliMUONTriggerTrack* track;
110 while ( ( track = static_cast<AliMUONTriggerTrack*>(next()) ) )
112 nadded += GenerateClusters(iChamber,*track,clusterStore);
117 //_____________________________________________________________________________
119 AliMUONTriggerTrackToTrackerClusters::GenerateClusters(Int_t iChamber,
120 const AliMUONTriggerTrack& track,
121 AliMUONVClusterStore& clusterStore) const
123 /// From a trigger track, generate 1 cluster in given chamber
125 /// Get a (rough) guestimate of the track momentum
129 Double_t z = AliMUONConstants::DefaultChamberZ(10);
131 Double_t bendingCoord = track.GetY11();
132 Double_t bendingSlope = TMath::Tan(track.GetThetay());
134 Double_t bendingImpact = bendingCoord - z * bendingSlope;
136 AliDebug(1,Form("TriggerTrack impact parameter=%e",bendingImpact));
138 // StdoutToAliDebug(1,track.Print());
140 Double_t inverseBendingMomentum = 1. / AliMUONTrackExtrap::GetBendingMomentumFromImpactParam(bendingImpact);
142 // Construct an AliMUONTrackParam from the trigger track, in order to be able to extrapolate it
143 // to chambers 6..9 planes.
145 AliMUONTrackParam trackParam;
148 trackParam.SetNonBendingCoor(track.GetX11());
149 trackParam.SetNonBendingSlope(TMath::Tan(track.GetThetax()));
150 trackParam.SetBendingCoor(bendingCoord);
151 trackParam.SetBendingSlope(bendingSlope);
152 trackParam.SetInverseBendingMomentum(inverseBendingMomentum);
154 Double_t dZ = AliMUONConstants::DefaultChamberZ(10) - AliMUONConstants::DefaultChamberZ(12);
156 Double_t sigmaX = AliMUONConstants::TriggerNonBendingReso();
158 Double_t sigmaY = AliMUONConstants::TriggerBendingReso();
160 // Compute and set track parameters covariances
161 TMatrixD paramCov(5,5);
165 paramCov(0,0) = sigmaX*sigmaX;
166 paramCov(0,1) = paramCov(0,0)/dZ;
167 paramCov(1,0) = paramCov(0,1);
168 paramCov(1,1) = 2.0*paramCov(0,0)/dZ/dZ;
171 paramCov(2,2) = sigmaY*sigmaY;
172 paramCov(2,3) = paramCov(2,2)/dZ;
173 paramCov(3,2) = paramCov(2,3);
174 paramCov(3,3) = 2.0*paramCov(2,2)/dZ/dZ;
176 // Inverse bending momentum (50% error)
177 paramCov(4,4) = 0.5*inverseBendingMomentum * 0.5*inverseBendingMomentum;
180 trackParam.SetCovariances(paramCov);
182 // add MCS effect in the iron wall
183 const Float_t kFilterThickness = AliMUONConstants::MuonFilterZEnd()-AliMUONConstants::MuonFilterZBeg(); // cm
184 AliMUONTrackExtrap::ExtrapToZCov(&trackParam, AliMUONConstants::MuonFilterZEnd()); // Extrap to iChamber
185 AliMUONTrackExtrap::AddMCSEffect(&trackParam, kFilterThickness, AliMUONConstants::MuonFilterX0()); // Add MCS effects
187 // Now we extrapolate this trackParam to chambers 6 -> 9
188 Int_t nclusters = clusterStore.GetSize();
190 AliMUONTrackParam tp(trackParam);
192 Double_t zg = AliMUONConstants::DefaultChamberZ(iChamber);
193 AliMUONTrackExtrap::ExtrapToZCov(&tp, zg); // Extrap to iChamber
196 AliDebug(1,Form("iChamber=%d",iChamber));
198 StdoutToAliDebug(1,tp.Print("FULLCOV"););
200 Double_t x = tp.GetNonBendingCoor();
201 Double_t y = tp.GetBendingCoor();
202 const TMatrixD& cov = tp.GetCovariances();
203 Double_t ex = TMath::Sqrt(cov(0,0));
204 Double_t ey = TMath::Sqrt(cov(2,2));
208 Int_t detElemId = DetElemId(iChamber,x,y,ex,ey,zde);
210 AliDebug(1,Form("zg = %e zde = %e",zg,zde));
212 if ( AliMpDEManager::IsValidDetElemId(detElemId) )
214 AliMUONVCluster* rawCluster = clusterStore.Add(AliMpDEManager::GetChamberId(detElemId), detElemId, nclusters);
219 rawCluster->SetCharge(100.0);
220 rawCluster->SetXYZ(x, y, zg);
221 rawCluster->SetErrXY(ex,ey);
225 AliWarning(Form("No DE found at xg=%e yg=%e",x,y));