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 **************************************************************************/
19 //-----------------------------------------------------------------------------
20 /// \class AliMUONTrackHitPattern
22 /// This class propagates tracks to trigger chambers
23 /// searching for fired strips.
25 /// To each track, a hit pattern for trigger chambers is set.
26 /// The hit pattern is a UShort_t with 8 bits used:
30 /// ----------- ------------
31 /// chamber: 11 12 13 14 | 11 12 13 14
32 /// cathode: bending | non-bending
34 /// The main method is:
37 /// \author Diego Stocco
38 //-----------------------------------------------------------------------------
41 #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"
56 #include "AliMpSegmentation.h"
57 #include "AliMpVSegmentation.h"
61 #include "AliTracker.h"
63 #include <Riostream.h>
65 #include <TClonesArray.h>
70 ClassImp(AliMUONTrackHitPattern) // Class implementation in ROOT context
74 //______________________________________________________________________________
75 AliMUONTrackHitPattern::AliMUONTrackHitPattern(const AliMUONGeometryTransformer& transformer,
76 const AliMUONDigitMaker& digitMaker)
78 fTransformer(transformer),
79 fDigitMaker(digitMaker)
81 /// Default constructor
84 const AliMagF* kField = AliTracker::GetFieldMap();
85 if (!kField) AliFatal("No field available");
86 AliMUONTrackExtrap::SetField(kField);
90 //______________________________________________________________________________
91 AliMUONTrackHitPattern::~AliMUONTrackHitPattern(void)
97 //______________________________________________________________________________
98 void AliMUONTrackHitPattern::GetHitPattern(AliMUONVTrackStore& trackStore,
99 const AliMUONVTriggerStore& triggerStore) const
103 /// Loops on reco tracks, extrapolates them to trigger chambers
104 /// and searches for matching digits
107 const Int_t kMask[2][4]= {{0x80, 0x40, 0x20, 0x10},
108 {0x08, 0x04, 0x02, 0x01}};
113 AliMUONDigitStoreV1 digitStore;
115 TriggerDigits(triggerStore,digitStore);
117 AliMUONTrack* muonTrack;
118 TIter next(trackStore.CreateIterator());
120 while ( ( muonTrack = static_cast<AliMUONTrack*>(next()) ) )
123 AliMUONTrackParam trackParam = (*(static_cast<AliMUONTrackParam*>
124 (muonTrack->GetTrackParamAtHit()->Last())));
126 for(Int_t ch=0; ch<4; ++ch)
128 AliMUONTrackExtrap::ExtrapToZCov(&trackParam, AliMUONConstants::DefaultChamberZ(10+ch));
129 FindPadMatchingTrack(digitStore,trackParam, isMatch, ch);
130 for(Int_t cath=0; cath<2; ++cath)
132 if(isMatch[cath]) pattern |= kMask[cath][ch];
135 muonTrack->SetHitsPatternInTrigCh(pattern);
140 //______________________________________________________________________________
142 AliMUONTrackHitPattern::FindPadMatchingTrack(AliMUONVDigitStore& digitStore,
143 const AliMUONTrackParam& trackParam,
144 Bool_t isMatch[2], Int_t /*iChamber*/) const
147 /// Given track position, searches for matching digits.
150 Float_t minMatchDist[2];
152 for(Int_t cath=0; cath<2; ++cath)
154 isMatch[cath]=kFALSE;
155 minMatchDist[cath]=9999.;
158 TIter next(digitStore.CreateIterator());
159 AliMUONVDigit* mDigit;
161 while ( ( mDigit = static_cast<AliMUONVDigit*>(next()) ) )
163 Int_t currDetElemId = mDigit->DetElemId();
164 Int_t cathode = mDigit->Cathode();
165 Int_t ix = mDigit->PadX();
166 Int_t iy = mDigit->PadY();
167 Float_t xpad, ypad, zpad;
168 const AliMpVSegmentation* seg = AliMpSegmentation::Instance()
169 ->GetMpSegmentation(currDetElemId,AliMp::GetCathodType(cathode));
171 AliMpPad pad = seg->PadByIndices(AliMpIntPair(ix,iy),kTRUE);
172 Float_t xlocal1 = pad.Position().X();
173 Float_t ylocal1 = pad.Position().Y();
174 Float_t dpx = pad.Dimensions().X();
175 Float_t dpy = pad.Dimensions().Y();
176 fTransformer.Local2Global(currDetElemId, xlocal1, ylocal1, 0, xpad, ypad, zpad);
177 Float_t matchDist = MinDistanceFromPad(xpad, ypad, zpad, dpx, dpy, trackParam);
178 if(matchDist>minMatchDist[cathode])continue;
179 isMatch[cathode] = kTRUE;
180 minMatchDist[cathode] = matchDist;
185 //______________________________________________________________________________
187 AliMUONTrackHitPattern::MinDistanceFromPad(Float_t xPad, Float_t yPad, Float_t zPad,
188 Float_t dpx, Float_t dpy,
189 const AliMUONTrackParam& trackParam) const
192 /// Decides if the digit belongs to the track.
194 Float_t xTrackAtPad = trackParam.GetNonBendingCoor();
195 Float_t yTrackAtPad = trackParam.GetBendingCoor();
197 Float_t sigmaX, sigmaY, sigmaMS;
198 GetPosUncertainty(trackParam, zPad, sigmaX, sigmaY, sigmaMS);
200 Float_t maxDistX = 3.*(sigmaX + sigmaMS); // in cm
201 Float_t maxDistY = 3.*(sigmaY + sigmaMS); // in cm
203 Float_t deltaX = TMath::Abs(xPad-xTrackAtPad)-dpx;
204 Float_t deltaY = TMath::Abs(yPad-yTrackAtPad)-dpy;
206 Float_t matchDist = 99999.;
207 if(deltaX<=maxDistX && deltaY<=maxDistY) matchDist = TMath::Max(deltaX, deltaY);
212 //______________________________________________________________________________
214 AliMUONTrackHitPattern::GetPosUncertainty(const AliMUONTrackParam& trackParam,
216 Float_t &sigmaX, Float_t &sigmaY,
217 Float_t &sigmaMS) const
220 /// Returns uncertainties on extrapolated position.
221 /// Takes into account Branson plane corrections in the iron wall.
224 const Float_t kAlpha = 0.1123; // GeV/c
226 // Find a better way to get such parameters ???
227 const Float_t kZFilterIn = 1471.; // From STRUCT/SHILConst2.h
228 const Float_t kZFilterOut = kZFilterIn + 120.; // From STRUCT/SHILConst2.h
230 const Float_t kZBranson = - (kZFilterIn + (kZFilterOut - kZFilterIn)*2./3. ); // - sign because distance are positive
231 Float_t zDistFromWall = TMath::Abs(zChamber - kZBranson);
232 Float_t zDistFromLastTrackCh = TMath::Abs(zChamber - AliMUONConstants::DefaultChamberZ(9));
234 const TMatrixD& kCovParam = trackParam.GetCovariances();
236 sigmaX = kCovParam(0,0);
237 sigmaY = kCovParam(2,2);
239 // If covariance matrix is not extrapolated, use "reasonable" errors
240 // (To be removed as soon as covariance matrix is correctly propagated).
241 if (sigmaX==0.)sigmaX = 0.003 * zDistFromLastTrackCh;
242 if (sigmaY==0.)sigmaY = 0.004 * zDistFromLastTrackCh;
244 Float_t p = trackParam.P();
245 Float_t thetaMS = kAlpha/p;
246 sigmaMS = zDistFromWall * TMath::Tan(thetaMS);
250 //______________________________________________________________________________
252 AliMUONTrackHitPattern::TriggerDigits(const AliMUONVTriggerStore& triggerStore,
253 AliMUONVDigitStore& digitStore) const
256 /// make (S)Digit for trigger
261 AliMUONLocalTrigger* locTrg;
262 TIter next(triggerStore.CreateLocalIterator());
264 while ( ( locTrg = static_cast<AliMUONLocalTrigger*>(next()) ) )
266 if (locTrg->IsNull()) continue;
268 TArrayS xyPattern[2];
269 locTrg->GetXPattern(xyPattern[0]);
270 locTrg->GetYPattern(xyPattern[1]);
272 // do we need this ? (Ch.F.)
273 // for(Int_t cath=0; cath<2; ++cath)
275 // for(Int_t ch=0; ch<4; ++ch)
277 // if(xyPattern[cath][ch]==0) continue;
281 Int_t nBoard = locTrg->LoCircuit();
282 fDigitMaker.TriggerDigits(nBoard, xyPattern, digitStore);