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 **************************************************************************/
16 ////////////////////////////////////
18 /// \class AliMUONTrackHitPattern
20 /// This class propagates tracks to trigger chambers
21 /// searching for fired strips.
23 /// To each track, a hit pattern for trigger chambers is set.
24 /// The hit pattern is a UShort_t with 8 bits used:
28 /// ----------- ------------
29 /// chamber: 11 12 13 14 | 11 12 13 14
30 /// cathode: bending | non-bending
32 /// The main method is:
35 /// \author Diego Stocco
37 ////////////////////////////////////
40 #include "AliMUONTrackHitPattern.h"
43 #include "AliMUONConstants.h"
44 #include "AliMUONVDigit.h"
45 #include "AliMUONDigitMaker.h"
46 #include "AliMUONDigitStoreV1.h"
47 #include "AliMUONGeometryTransformer.h"
48 #include "AliMUONLocalTrigger.h"
49 #include "AliMUONLocalTriggerBoard.h"
50 #include "AliMUONTrack.h"
51 #include "AliMUONTrackExtrap.h"
52 #include "AliMUONTrackParam.h"
53 #include "AliMUONVTrackStore.h"
54 #include "AliMUONVTriggerStore.h"
57 #include "AliMpSegmentation.h"
58 #include "AliMpVSegmentation.h"
59 #include "AliTracker.h"
60 #include <Riostream.h>
62 #include <TClonesArray.h>
67 ClassImp(AliMUONTrackHitPattern) // Class implementation in ROOT context
71 //______________________________________________________________________________
72 AliMUONTrackHitPattern::AliMUONTrackHitPattern(const AliMUONGeometryTransformer& transformer,
73 const AliMUONDigitMaker& digitMaker)
75 fTransformer(transformer),
76 fDigitMaker(digitMaker)
78 /// Default constructor
81 const AliMagF* kField = AliTracker::GetFieldMap();
82 if (!kField) AliFatal("No field available");
83 AliMUONTrackExtrap::SetField(kField);
87 //______________________________________________________________________________
88 AliMUONTrackHitPattern::~AliMUONTrackHitPattern(void)
94 //______________________________________________________________________________
95 void AliMUONTrackHitPattern::GetHitPattern(AliMUONVTrackStore& trackStore,
96 const AliMUONVTriggerStore& triggerStore) const
100 /// Loops on reco tracks, extrapolates them to trigger chambers
101 /// and searches for matching digits
104 const Int_t kMask[2][4]= {{0x80, 0x40, 0x20, 0x10},
105 {0x08, 0x04, 0x02, 0x01}};
110 AliMUONDigitStoreV1 digitStore;
112 TriggerDigits(triggerStore,digitStore);
114 AliMUONTrack* muonTrack;
115 TIter next(trackStore.CreateIterator());
117 while ( ( muonTrack = static_cast<AliMUONTrack*>(next()) ) )
120 AliMUONTrackParam *trackParam = static_cast<AliMUONTrackParam*>
121 (muonTrack->GetTrackParamAtHit()->Last());
123 for(Int_t ch=0; ch<4; ++ch)
125 AliMUONTrackExtrap::ExtrapToZCov(trackParam, AliMUONConstants::DefaultChamberZ(10+ch));
126 FindPadMatchingTrack(digitStore,*trackParam, isMatch, ch);
127 for(Int_t cath=0; cath<2; ++cath)
129 if(isMatch[cath]) pattern |= kMask[cath][ch];
132 muonTrack->SetHitsPatternInTrigCh(pattern);
137 //______________________________________________________________________________
139 AliMUONTrackHitPattern::FindPadMatchingTrack(AliMUONVDigitStore& digitStore,
140 const AliMUONTrackParam& trackParam,
141 Bool_t isMatch[2], Int_t /*iChamber*/) const
144 /// Given track position, searches for matching digits.
147 Float_t minMatchDist[2];
149 for(Int_t cath=0; cath<2; ++cath)
151 isMatch[cath]=kFALSE;
152 minMatchDist[cath]=9999.;
155 TIter next(digitStore.CreateIterator());
156 AliMUONVDigit* mDigit;
158 while ( ( mDigit = static_cast<AliMUONVDigit*>(next()) ) )
160 Int_t currDetElemId = mDigit->DetElemId();
161 Int_t cathode = mDigit->Cathode();
162 Int_t ix = mDigit->PadX();
163 Int_t iy = mDigit->PadY();
164 Float_t xpad, ypad, zpad;
165 const AliMpVSegmentation* seg = AliMpSegmentation::Instance()
166 ->GetMpSegmentation(currDetElemId,AliMp::GetCathodType(cathode));
168 AliMpPad pad = seg->PadByIndices(AliMpIntPair(ix,iy),kTRUE);
169 Float_t xlocal1 = pad.Position().X();
170 Float_t ylocal1 = pad.Position().Y();
171 Float_t dpx = pad.Dimensions().X();
172 Float_t dpy = pad.Dimensions().Y();
173 fTransformer.Local2Global(currDetElemId, xlocal1, ylocal1, 0, xpad, ypad, zpad);
174 Float_t matchDist = MinDistanceFromPad(xpad, ypad, zpad, dpx, dpy, trackParam);
175 if(matchDist>minMatchDist[cathode])continue;
176 isMatch[cathode] = kTRUE;
177 minMatchDist[cathode] = matchDist;
182 //______________________________________________________________________________
184 AliMUONTrackHitPattern::MinDistanceFromPad(Float_t xPad, Float_t yPad, Float_t zPad,
185 Float_t dpx, Float_t dpy,
186 const AliMUONTrackParam& trackParam) const
189 /// Decides if the digit belongs to the track.
191 Float_t xTrackAtPad = trackParam.GetNonBendingCoor();
192 Float_t yTrackAtPad = trackParam.GetBendingCoor();
194 Float_t sigmaX, sigmaY, sigmaMS;
195 GetPosUncertainty(trackParam, zPad, sigmaX, sigmaY, sigmaMS);
197 Float_t maxDistX = 3.*(sigmaX + sigmaMS); // in cm
198 Float_t maxDistY = 3.*(sigmaY + sigmaMS); // in cm
200 Float_t deltaX = TMath::Abs(xPad-xTrackAtPad)-dpx;
201 Float_t deltaY = TMath::Abs(yPad-yTrackAtPad)-dpy;
203 Float_t matchDist = 99999.;
204 if(deltaX<=maxDistX && deltaY<=maxDistY) matchDist = TMath::Max(deltaX, deltaY);
209 //______________________________________________________________________________
211 AliMUONTrackHitPattern::GetPosUncertainty(const AliMUONTrackParam& trackParam,
213 Float_t &sigmaX, Float_t &sigmaY,
214 Float_t &sigmaMS) const
217 /// Returns uncertainties on extrapolated position.
218 /// Takes into account Branson plane corrections in the iron wall.
221 const Float_t kAlpha = 0.1123; // GeV/c
223 // Find a better way to get such parameters ???
224 const Float_t kZFilterIn = 1471.; // From STRUCT/SHILConst2.h
225 const Float_t kZFilterOut = kZFilterIn + 120.; // From STRUCT/SHILConst2.h
227 const Float_t kZBranson = - (kZFilterIn + (kZFilterOut - kZFilterIn)*2./3. ); // - sign because distance are positive
228 Float_t zDistFromWall = TMath::Abs(zChamber - kZBranson);
229 Float_t zDistFromLastTrackCh = TMath::Abs(zChamber - AliMUONConstants::DefaultChamberZ(9));
231 TMatrixD *covParam = trackParam.GetCovariances();
233 sigmaX = (*covParam)(0,0);
234 sigmaY = (*covParam)(2,2);
236 // If covariance matrix is not extrapolated, use "reasonable" errors
237 // (To be removed as soon as covariance matrix is correctly propagated).
238 if (sigmaX==0.)sigmaX = 0.003 * zDistFromLastTrackCh;
239 if (sigmaY==0.)sigmaY = 0.004 * zDistFromLastTrackCh;
241 Float_t p = trackParam.P();
242 Float_t thetaMS = kAlpha/p;
243 sigmaMS = zDistFromWall * TMath::Tan(thetaMS);
247 //______________________________________________________________________________
249 AliMUONTrackHitPattern::TriggerDigits(const AliMUONVTriggerStore& triggerStore,
250 AliMUONVDigitStore& digitStore) const
253 /// make (S)Digit for trigger
258 AliMUONLocalTrigger* locTrg;
259 TIter next(triggerStore.CreateLocalIterator());
261 while ( ( locTrg = static_cast<AliMUONLocalTrigger*>(next()) ) )
263 TArrayS xyPattern[2];
267 xyPattern[0].AddAt(locTrg->GetX1Pattern(),0);
268 xyPattern[0].AddAt(locTrg->GetX2Pattern(),1);
269 xyPattern[0].AddAt(locTrg->GetX3Pattern(),2);
270 xyPattern[0].AddAt(locTrg->GetX4Pattern(),3);
272 xyPattern[1].AddAt(locTrg->GetY1Pattern(),0);
273 xyPattern[1].AddAt(locTrg->GetY2Pattern(),1);
274 xyPattern[1].AddAt(locTrg->GetY3Pattern(),2);
275 xyPattern[1].AddAt(locTrg->GetY4Pattern(),3);
277 for(Int_t cath=0; cath<2; ++cath)
279 for(Int_t ch=0; ch<4; ++ch)
281 if(xyPattern[cath][ch]==0) continue;
285 Int_t nBoard = locTrg->LoCircuit();
286 fDigitMaker.TriggerDigits(nBoard, xyPattern, digitStore);