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d3da6dc4 | 1 | /************************************************************************** |
2 | * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. * | |
3 | * * | |
4 | * Author: The ALICE Off-line Project. * | |
5 | * Contributors are mentioned in the code where appropriate. * | |
6 | * * | |
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 | **************************************************************************/ | |
15 | ||
16 | ////////////////////////////////////////////////////////////////////////// | |
17 | // // | |
18 | // AliHMPIDRecon // | |
19 | // // | |
20 | // HMPID class to perfom pattern recognition based on Hough transfrom // | |
21 | // for single chamber // | |
22 | ////////////////////////////////////////////////////////////////////////// | |
23 | ||
a591e55f | 24 | #include "AliHMPIDRecon.h" //class header |
d3da6dc4 | 25 | #include "AliHMPIDCluster.h" //CkovAngle() |
a591e55f | 26 | #include <TRotation.h> //TracePhot() |
27 | #include <TH1D.h> //HoughResponse() | |
28 | #include <TClonesArray.h> //CkovAngle() | |
29 | #include <AliESDtrack.h> //CkovAngle() | |
d3da6dc4 | 30 | |
d3da6dc4 | 31 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
ffb1ac19 | 32 | AliHMPIDRecon::AliHMPIDRecon():TTask("RichRec","RichPat") |
d3da6dc4 | 33 | { |
ffb1ac19 | 34 | //.. |
35 | //init of data members | |
36 | //.. | |
37 | ||
38 | fPhotCnt = -1; | |
39 | fPhotFlag = 0x0; | |
40 | fPhotCkov = 0x0; | |
41 | fPhotPhi = 0x0; | |
42 | fPhotWei = 0x0; | |
43 | fCkovSigma2 = 0; | |
44 | fIsWEIGHT = kFALSE; | |
45 | fDTheta = 0.001; | |
46 | fWindowWidth = 0.045; | |
47 | fTrkDir = TVector3(0,0,1); // init just for test | |
48 | fTrkPos = TVector2(30,40); // init just for test | |
49 | ||
50 | AliHMPIDParam *pParam=AliHMPIDParam::Instance(); | |
51 | fParam = pParam; | |
52 | ||
53 | fParam->SetRefIdx(fParam->MeanIdxRad()); // initialization of ref index to a default one | |
54 | } | |
55 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
56 | void AliHMPIDRecon::InitVars(Int_t n) | |
57 | { | |
58 | //.. | |
59 | //Init some variables | |
60 | //.. | |
61 | if(n<0) return; | |
62 | fPhotFlag = new Int_t[n]; | |
63 | fPhotCkov = new Double_t[n]; | |
64 | fPhotPhi = new Double_t[n]; | |
65 | fPhotWei = new Double_t[n]; | |
66 | // | |
67 | } | |
68 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
69 | void AliHMPIDRecon::DeleteVars() | |
70 | { | |
71 | //.. | |
72 | //Delete variables | |
73 | //.. | |
74 | delete fPhotFlag; | |
75 | delete fPhotCkov; | |
76 | delete fPhotPhi; | |
77 | delete fPhotWei; | |
d3da6dc4 | 78 | } |
79 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
afe12692 | 80 | void AliHMPIDRecon::CkovAngle(AliESDtrack *pTrk,TClonesArray *pCluLst,Double_t nmean,Double_t qthre) |
d3da6dc4 | 81 | { |
82 | // Pattern recognition method based on Hough transform | |
59280a5a | 83 | // Arguments: pTrk - track for which Ckov angle is to be found |
84 | // pCluLst - list of clusters for this chamber | |
85 | // Returns: - track ckov angle, [rad], | |
a591e55f | 86 | |
ffb1ac19 | 87 | Int_t nClusTot = pCluLst->GetEntries(); |
88 | if(nClusTot>fParam->MultCut()) fIsWEIGHT = kTRUE; // offset to take into account bkg in reconstruction | |
89 | else fIsWEIGHT = kFALSE; | |
d3da6dc4 | 90 | |
ffb1ac19 | 91 | InitVars(nClusTot); |
92 | ||
611e810d | 93 | Float_t xRa,yRa,th,ph; |
a591e55f | 94 | pTrk->GetHMPIDtrk(xRa,yRa,th,ph); //initialize this track: th and ph angles at middle of RAD |
a591e55f | 95 | SetTrack(xRa,yRa,th,ph); |
611e810d | 96 | |
ffb1ac19 | 97 | fParam->SetRefIdx(nmean); |
d3da6dc4 | 98 | |
59280a5a | 99 | Float_t dMin=999,mipX=-1,mipY=-1;Int_t chId=-1,mipId=-1,mipQ=-1; |
d3da6dc4 | 100 | fPhotCnt=0; |
101 | for (Int_t iClu=0; iClu<pCluLst->GetEntriesFast();iClu++){//clusters loop | |
102 | AliHMPIDCluster *pClu=(AliHMPIDCluster*)pCluLst->UncheckedAt(iClu); //get pointer to current cluster | |
59280a5a | 103 | chId=pClu->Ch(); |
afe12692 | 104 | if(pClu->Q()>qthre){ //charge compartible with MIP clusters |
a591e55f | 105 | Float_t dX=fPc.X()-pClu->X(),dY=fPc.Y()-pClu->Y(),d =TMath::Sqrt(dX*dX+dY*dY); //distance between current cluster and intersection point |
106 | if( d < dMin) {mipId=iClu; dMin=d;mipX=pClu->X();mipY=pClu->Y();mipQ=(Int_t)pClu->Q();} //current cluster is closer, overwrite data for min cluster | |
107 | }else{ //charge compatible with photon cluster | |
108 | Double_t thetaCer,phiCer; | |
109 | if(FindPhotCkov(pClu->X(),pClu->Y(),thetaCer,phiCer)){ //find ckov angle for this photon candidate | |
110 | fPhotCkov[fPhotCnt]=thetaCer; //actual theta Cerenkov (in TRS) | |
b4ad85e9 | 111 | fPhotPhi [fPhotCnt]=phiCer; //actual phi Cerenkov (in TRS): -pi to come back to "unusual" ref system (X,Y,-Z) |
28500fe1 | 112 | //PH Printf("photon n. %i reconstructed theta = %f",fPhotCnt,fPhotCkov[fPhotCnt]); |
a591e55f | 113 | fPhotCnt++; //increment counter of photon candidates |
114 | } | |
59280a5a | 115 | } |
d3da6dc4 | 116 | }//clusters loop |
4598109f | 117 | fMipPos.Set(mipX,mipY); |
76fd1a96 | 118 | if(fPhotCnt<=3) pTrk->SetHMPIDsignal(kNoPhotAccept); //no reconstruction with <=3 photon candidates |
2d1a9b21 | 119 | Int_t iNrec=FlagPhot(HoughResponse()); //flag photons according to individual theta ckov with respect to most probable |
120 | pTrk->SetHMPIDmip(mipX,mipY,mipQ,iNrec); //store mip info | |
59280a5a | 121 | |
a591e55f | 122 | if(mipId==-1) {pTrk->SetHMPIDsignal(kMipQdcCut); return;} //no clusters with QDC more the threshold at all |
ffb1ac19 | 123 | if(dMin>fParam->DistCut()) {pTrk->SetHMPIDsignal(kMipDistCut); return;} //closest cluster with enough charge is still too far from intersection |
a591e55f | 124 | pTrk->SetHMPIDcluIdx(chId,mipId); //set index of cluster |
2d1a9b21 | 125 | if(iNrec<1){ |
126 | pTrk->SetHMPIDsignal(kNoPhotAccept); //no photon candidates are accepted | |
76fd1a96 | 127 | } |
128 | else { | |
2d1a9b21 | 129 | Double_t thetaC = FindRingCkov(pCluLst->GetEntries()); //find the best reconstructed theta Cherenkov |
130 | // FindRingGeom(thetaC,2); | |
131 | pTrk->SetHMPIDsignal(thetaC); //store theta Cherenkov | |
132 | pTrk->SetHMPIDchi2(fCkovSigma2); //store errors squared | |
76fd1a96 | 133 | } |
d3da6dc4 | 134 | |
ffb1ac19 | 135 | DeleteVars(); |
43400d2d | 136 | }//CkovAngle() |
d3da6dc4 | 137 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
a591e55f | 138 | Bool_t AliHMPIDRecon::FindPhotCkov(Double_t cluX,Double_t cluY,Double_t &thetaCer,Double_t &phiCer) |
d3da6dc4 | 139 | { |
140 | // Finds Cerenkov angle for this photon candidate | |
141 | // Arguments: cluX,cluY - position of cadidate's cluster | |
a591e55f | 142 | // Returns: Cerenkov angle |
d3da6dc4 | 143 | |
a591e55f | 144 | TVector3 dirCkov; |
145 | ||
ffb1ac19 | 146 | Double_t zRad= -0.5*fParam->RadThick()-0.5*fParam->WinThick(); //z position of middle of RAD |
67a1c24c | 147 | TVector3 rad(fTrkPos.X(),fTrkPos.Y(),zRad); //impact point at middle of RAD |
ffb1ac19 | 148 | TVector3 pc(cluX,cluY,0.5*fParam->WinThick()+fParam->GapIdx()); //mip at PC |
a591e55f | 149 | Double_t cluR = TMath::Sqrt((cluX-fTrkPos.X())*(cluX-fTrkPos.X())+ |
150 | (cluY-fTrkPos.Y())*(cluY-fTrkPos.Y()));//ref. distance impact RAD-CLUSTER | |
67a1c24c | 151 | Double_t phi=(pc-rad).Phi(); //phi of photon |
a591e55f | 152 | |
b4ad85e9 | 153 | Double_t ckov1=0; |
67a1c24c | 154 | Double_t ckov2=0.75+fTrkDir.Theta(); //start to find theta cerenkov in DRS |
b4ad85e9 | 155 | const Double_t kTol=0.01; |
d3da6dc4 | 156 | Int_t iIterCnt = 0; |
157 | while(1){ | |
a591e55f | 158 | if(iIterCnt>=50) return kFALSE; |
d3da6dc4 | 159 | Double_t ckov=0.5*(ckov1+ckov2); |
67a1c24c | 160 | dirCkov.SetMagThetaPhi(1,ckov,phi); |
a591e55f | 161 | TVector2 posC=TraceForward(dirCkov); //trace photon with actual angles |
162 | Double_t dist=cluR-(posC-fTrkPos).Mod(); //get distance between trial point and cluster position | |
163 | if(posC.X()==-999) dist = - 999; //total reflection problem | |
164 | iIterCnt++; //counter step | |
b4ad85e9 | 165 | if (dist> kTol) ckov1=ckov; //cluster @ larger ckov |
d3da6dc4 | 166 | else if(dist<-kTol) ckov2=ckov; //cluster @ smaller ckov |
a591e55f | 167 | else{ //precision achived: ckov in DRS found |
168 | dirCkov.SetMagThetaPhi(1,ckov,phi); // | |
2d1a9b21 | 169 | Lors2Trs(dirCkov,thetaCer,phiCer); //find ckov (in TRS:the effective Cherenkov angle!) |
a591e55f | 170 | return kTRUE; |
171 | } | |
d3da6dc4 | 172 | } |
173 | }//FindPhotTheta() | |
174 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
a591e55f | 175 | TVector2 AliHMPIDRecon::TraceForward(TVector3 dirCkov)const |
d3da6dc4 | 176 | { |
a591e55f | 177 | //Trace forward a photon from (x,y) up to PC |
178 | // Arguments: dirCkov photon vector in LORS | |
179 | // Returns: pos of traced photon at PC | |
ffb1ac19 | 180 | |
a591e55f | 181 | TVector2 pos(-999,-999); |
67a1c24c | 182 | Double_t thetaCer = dirCkov.Theta(); |
ffb1ac19 | 183 | if(thetaCer > TMath::ASin(1./fParam->GetRefIdx())) return pos; //total refraction on WIN-GAP boundary |
184 | Double_t zRad= -0.5*fParam->RadThick()-0.5*fParam->WinThick(); //z position of middle of RAD | |
185 | TVector3 posCkov(fTrkPos.X(),fTrkPos.Y(),zRad); //RAD: photon position is track position @ middle of RAD | |
186 | Propagate(dirCkov,posCkov, -0.5*fParam->WinThick()); //go to RAD-WIN boundary | |
187 | Refract (dirCkov, fParam->GetRefIdx(),fParam->WinIdx()); //RAD-WIN refraction | |
188 | Propagate(dirCkov,posCkov, 0.5*fParam->WinThick()); //go to WIN-GAP boundary | |
189 | Refract (dirCkov, fParam->WinIdx(),fParam->GapIdx()); //WIN-GAP refraction | |
190 | Propagate(dirCkov,posCkov,0.5*fParam->WinThick()+fParam->GapThick()); //go to PC | |
a591e55f | 191 | pos.Set(posCkov.X(),posCkov.Y()); |
192 | return pos; | |
193 | }//TraceForward() | |
194 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
2d1a9b21 | 195 | void AliHMPIDRecon::Lors2Trs(TVector3 dirCkov,Double_t &thetaCer,Double_t &phiCer)const |
a591e55f | 196 | { |
197 | //Theta Cerenkov reconstruction | |
2d1a9b21 | 198 | // Arguments: dirCkov photon vector in LORS |
199 | // Returns: thetaCer of photon in TRS | |
200 | // phiCer of photon in TRS | |
a591e55f | 201 | // TVector3 dirTrk; |
202 | // dirTrk.SetMagThetaPhi(1,fTrkDir.Theta(),fTrkDir.Phi()); | |
203 | // Double_t thetaCer = TMath::ACos(dirCkov*dirTrk); | |
2d1a9b21 | 204 | TRotation mtheta; mtheta.RotateY(-fTrkDir.Theta()); |
205 | TRotation mphi; mphi.RotateZ(-fTrkDir.Phi()); | |
a591e55f | 206 | TRotation mrot=mtheta*mphi; |
207 | TVector3 dirCkovTRS; | |
208 | dirCkovTRS=mrot*dirCkov; | |
209 | phiCer = dirCkovTRS.Phi(); //actual value of the phi of the photon | |
210 | thetaCer= dirCkovTRS.Theta(); //actual value of thetaCerenkov of the photon | |
d3da6dc4 | 211 | } |
212 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
2d1a9b21 | 213 | void AliHMPIDRecon::Trs2Lors(TVector3 dirCkov,Double_t &thetaCer,Double_t &phiCer)const |
214 | { | |
215 | //Theta Cerenkov reconstruction | |
216 | // Arguments: dirCkov photon vector in TRS | |
217 | // Returns: thetaCer of photon in LORS | |
218 | // phiCer of photon in LORS | |
219 | TRotation mtheta; mtheta.RotateY(fTrkDir.Theta()); | |
220 | TRotation mphi; mphi.RotateZ(fTrkDir.Phi()); | |
221 | TRotation mrot=mphi*mtheta; | |
222 | TVector3 dirCkovLORS; | |
223 | dirCkovLORS=mrot*dirCkov; | |
224 | phiCer = dirCkovLORS.Phi(); //actual value of the phi of the photon | |
225 | thetaCer= dirCkovLORS.Theta(); //actual value of thetaCerenkov of the photon | |
226 | } | |
227 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
228 | void AliHMPIDRecon::FindRingGeom(Double_t ckovAng,Int_t level) | |
d3da6dc4 | 229 | { |
4598109f | 230 | // Find area covered in the PC acceptance |
2d1a9b21 | 231 | // Arguments: ckovAng - cerenkov angle |
232 | // level - precision in finding area and portion of ring accepted (multiple of 50) | |
d3da6dc4 | 233 | // Returns: area of the ring in cm^2 for given theta ckov |
234 | ||
2d1a9b21 | 235 | Int_t kN=50*level; |
236 | Int_t nPoints = 0; | |
afe12692 | 237 | Double_t area=0; |
2d1a9b21 | 238 | |
4598109f | 239 | Bool_t first=kFALSE; |
2d1a9b21 | 240 | TVector2 pos1; |
241 | ||
afe12692 | 242 | for(Int_t i=0;i<kN;i++){ |
4598109f | 243 | if(!first) { |
2d1a9b21 | 244 | pos1=TracePhot(ckovAng,Double_t(TMath::TwoPi()*(i+1)/kN)); //find a good trace for the first photon |
4598109f | 245 | if(pos1.X()==-999) continue; //no area: open ring |
2d1a9b21 | 246 | if(!fParam->IsInside(pos1.X(),pos1.Y(),0)) { |
247 | pos1 = IntWithEdge(fMipPos,pos1); // find the very first intersection... | |
248 | } else { | |
249 | if(!AliHMPIDParam::IsInDead(pos1.X(),pos1.Y())) nPoints++; //photon is accepted if not in dead zone | |
250 | } | |
4598109f | 251 | first=kTRUE; |
252 | continue; | |
253 | } | |
254 | TVector2 pos2=TracePhot(ckovAng,Double_t(TMath::TwoPi()*(i+1)/kN)); //trace the next photon | |
255 | if(pos2.X()==-999) continue; //no area: open ring | |
ffb1ac19 | 256 | if(!fParam->IsInside(pos2.X(),pos2.Y(),0)) { |
4598109f | 257 | pos2 = IntWithEdge(fMipPos,pos2); |
2d1a9b21 | 258 | } else { |
259 | if(!AliHMPIDParam::IsInDead(pos2.X(),pos2.Y())) nPoints++; //photon is accepted if not in dead zone | |
4598109f | 260 | } |
261 | area+=TMath::Abs((pos1-fMipPos).X()*(pos2-fMipPos).Y()-(pos1-fMipPos).Y()*(pos2-fMipPos).X()); //add area of the triangle... | |
262 | pos1 = pos2; | |
d3da6dc4 | 263 | } |
2d1a9b21 | 264 | //--- find area and length of the ring; |
265 | fRingAcc = (Double_t)nPoints/(Double_t)kN; | |
7fc88c5e | 266 | area*=0.5; |
2d1a9b21 | 267 | fRingArea = area; |
268 | }//FindRingGeom() | |
d3da6dc4 | 269 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
4598109f | 270 | TVector2 AliHMPIDRecon::IntWithEdge(TVector2 p1,TVector2 p2)const |
271 | { | |
272 | // It finds the intersection of the line for 2 points traced as photons | |
273 | // and the edge of a given PC | |
274 | // Arguments: 2 points obtained tracing the photons | |
275 | // Returns: intersection point with detector (PC) edges | |
276 | ||
4598109f | 277 | Double_t xmin = (p1.X()<p2.X())? p1.X():p2.X(); |
278 | Double_t xmax = (p1.X()<p2.X())? p2.X():p1.X(); | |
279 | Double_t ymin = (p1.Y()<p2.Y())? p1.Y():p2.Y(); | |
280 | Double_t ymax = (p1.Y()<p2.Y())? p2.Y():p1.Y(); | |
281 | ||
282 | Double_t m = TMath::Tan((p2-p1).Phi()); | |
283 | TVector2 pint; | |
284 | //intersection with low X | |
285 | pint.Set((Double_t)(p1.X() + (0-p1.Y())/m),0.); | |
ffb1ac19 | 286 | if(pint.X()>=0 && pint.X()<=fParam->SizeAllX() && |
4598109f | 287 | pint.X()>=xmin && pint.X()<=xmax && |
288 | pint.Y()>=ymin && pint.Y()<=ymax) return pint; | |
289 | //intersection with high X | |
ffb1ac19 | 290 | pint.Set((Double_t)(p1.X() + (fParam->SizeAllY()-p1.Y())/m),(Double_t)(fParam->SizeAllY())); |
291 | if(pint.X()>=0 && pint.X()<=fParam->SizeAllX() && | |
4598109f | 292 | pint.X()>=xmin && pint.X()<=xmax && |
293 | pint.Y()>=ymin && pint.Y()<=ymax) return pint; | |
294 | //intersection with left Y | |
295 | pint.Set(0.,(Double_t)(p1.Y() + m*(0-p1.X()))); | |
ffb1ac19 | 296 | if(pint.Y()>=0 && pint.Y()<=fParam->SizeAllY() && |
4598109f | 297 | pint.Y()>=ymin && pint.Y()<=ymax && |
298 | pint.X()>=xmin && pint.X()<=xmax) return pint; | |
299 | //intersection with righ Y | |
ffb1ac19 | 300 | pint.Set((Double_t)(fParam->SizeAllX()),(Double_t)(p1.Y() + m*(fParam->SizeAllX()-p1.X()))); |
301 | if(pint.Y()>=0 && pint.Y()<=fParam->SizeAllY() && | |
4598109f | 302 | pint.Y()>=ymin && pint.Y()<=ymax && |
303 | pint.X()>=xmin && pint.X()<=xmax) return pint; | |
304 | return p1; | |
305 | }//IntWithEdge() | |
306 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
d3da6dc4 | 307 | Double_t AliHMPIDRecon::FindRingCkov(Int_t) |
308 | { | |
309 | // Loops on all Ckov candidates and estimates the best Theta Ckov for a ring formed by those candidates. Also estimates an error for that Theat Ckov | |
310 | // collecting errors for all single Ckov candidates thetas. (Assuming they are independent) | |
311 | // Arguments: iNclus- total number of clusters in chamber for background estimation | |
312 | // Return: best estimation of track Theta ckov | |
313 | ||
314 | Double_t wei = 0.; | |
315 | Double_t weightThetaCerenkov = 0.; | |
316 | ||
317 | Double_t ckovMin=9999.,ckovMax=0.; | |
318 | Double_t sigma2 = 0; //to collect error squared for this ring | |
319 | ||
320 | for(Int_t i=0;i<fPhotCnt;i++){//candidates loop | |
321 | if(fPhotFlag[i] == 2){ | |
a591e55f | 322 | if(fPhotCkov[i]<ckovMin) ckovMin=fPhotCkov[i]; //find max and min Theta ckov from all candidates within probable window |
d3da6dc4 | 323 | if(fPhotCkov[i]>ckovMax) ckovMax=fPhotCkov[i]; |
a591e55f | 324 | weightThetaCerenkov += fPhotCkov[i]*fPhotWei[i]; |
325 | wei += fPhotWei[i]; //collect weight as sum of all candidate weghts | |
d3da6dc4 | 326 | |
d3da6dc4 | 327 | sigma2 += 1./Sigma2(fPhotCkov[i],fPhotPhi[i]); |
328 | } | |
329 | }//candidates loop | |
330 | ||
331 | if(sigma2>0) fCkovSigma2=1./sigma2; | |
332 | else fCkovSigma2=1e10; | |
333 | ||
b4ad85e9 | 334 | if(wei != 0.) weightThetaCerenkov /= wei; else weightThetaCerenkov = 0.; |
d3da6dc4 | 335 | return weightThetaCerenkov; |
336 | }//FindCkovRing() | |
337 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
338 | Int_t AliHMPIDRecon::FlagPhot(Double_t ckov) | |
339 | { | |
340 | // Flag photon candidates if their individual ckov angle is inside the window around ckov angle returned by HoughResponse() | |
341 | // Arguments: ckov- value of most probable ckov angle for track as returned by HoughResponse() | |
342 | // Returns: number of photon candidates happened to be inside the window | |
343 | ||
a591e55f | 344 | // Photon Flag: Flag = 0 initial set; |
345 | // Flag = 1 good candidate (charge compatible with photon); | |
346 | // Flag = 2 photon used for the ring; | |
d3da6dc4 | 347 | |
348 | Int_t steps = (Int_t)((ckov )/ fDTheta); //how many times we need to have fDTheta to fill the distance between 0 and thetaCkovHough | |
349 | ||
350 | Double_t tmin = (Double_t)(steps - 1)*fDTheta; | |
351 | Double_t tmax = (Double_t)(steps)*fDTheta; | |
352 | Double_t tavg = 0.5*(tmin+tmax); | |
353 | ||
354 | tmin = tavg - 0.5*fWindowWidth; tmax = tavg + 0.5*fWindowWidth; | |
355 | ||
356 | Int_t iInsideCnt = 0; //count photons which Theta ckov inside the window | |
357 | for(Int_t i=0;i<fPhotCnt;i++){//photon candidates loop | |
afe12692 | 358 | fPhotFlag[i] = 0; |
d3da6dc4 | 359 | if(fPhotCkov[i] >= tmin && fPhotCkov[i] <= tmax) { |
360 | fPhotFlag[i]=2; | |
361 | iInsideCnt++; | |
362 | } | |
363 | } | |
364 | return iInsideCnt; | |
365 | }//FlagPhot() | |
366 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
a591e55f | 367 | TVector2 AliHMPIDRecon::TracePhot(Double_t ckovThe,Double_t ckovPhi)const |
d3da6dc4 | 368 | { |
369 | // Trace a single Ckov photon from emission point somewhere in radiator up to photocathode taking into account ref indexes of materials it travereses | |
ffb1ac19 | 370 | // Arguments: ckovThe,ckovPhi- photon ckov angles in TRS, [rad] |
d3da6dc4 | 371 | // Returns: distance between photon point on PC and track projection |
2d1a9b21 | 372 | |
373 | Double_t theta,phi; | |
374 | TVector3 dirTRS,dirLORS; | |
375 | dirTRS.SetMagThetaPhi(1,ckovThe,ckovPhi); //photon in TRS | |
376 | Trs2Lors(dirTRS,theta,phi); | |
377 | dirLORS.SetMagThetaPhi(1,theta,phi); //photon in LORS | |
378 | return TraceForward(dirLORS); //now foward tracing | |
a591e55f | 379 | }//TracePhot() |
d3da6dc4 | 380 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
a591e55f | 381 | void AliHMPIDRecon::Propagate(const TVector3 dir,TVector3 &pos,Double_t z)const |
d3da6dc4 | 382 | { |
383 | // Finds an intersection point between a line and XY plane shifted along Z. | |
384 | // Arguments: dir,pos - vector along the line and any point of the line | |
385 | // z - z coordinate of plain | |
386 | // Returns: none | |
387 | // On exit: pos is the position if this intesection if any | |
388 | static TVector3 nrm(0,0,1); | |
389 | TVector3 pnt(0,0,z); | |
390 | ||
391 | TVector3 diff=pnt-pos; | |
392 | Double_t sint=(nrm*diff)/(nrm*dir); | |
393 | pos+=sint*dir; | |
394 | }//Propagate() | |
395 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
396 | void AliHMPIDRecon::Refract(TVector3 &dir,Double_t n1,Double_t n2)const | |
397 | { | |
398 | // Refract direction vector according to Snell law | |
399 | // Arguments: | |
400 | // n1 - ref idx of first substance | |
401 | // n2 - ref idx of second substance | |
402 | // Returns: none | |
403 | // On exit: dir is new direction | |
67a1c24c | 404 | Double_t sinref=(n1/n2)*TMath::Sin(dir.Theta()); |
76fd1a96 | 405 | if(TMath::Abs(sinref)>1.) dir.SetXYZ(-999,-999,-999); |
67a1c24c | 406 | else dir.SetTheta(TMath::ASin(sinref)); |
d3da6dc4 | 407 | }//Refract() |
408 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
409 | Double_t AliHMPIDRecon::HoughResponse() | |
410 | { | |
411 | // | |
611e810d | 412 | // fIdxMip = mipId; |
413 | ||
d3da6dc4 | 414 | // |
415 | Double_t kThetaMax=0.75; | |
416 | Int_t nChannels = (Int_t)(kThetaMax/fDTheta+0.5); | |
417 | TH1D *phots = new TH1D("Rphot" ,"phots" ,nChannels,0,kThetaMax); | |
418 | TH1D *photsw = new TH1D("RphotWeighted" ,"photsw" ,nChannels,0,kThetaMax); | |
419 | TH1D *resultw = new TH1D("resultw","resultw" ,nChannels,0,kThetaMax); | |
420 | Int_t nBin = (Int_t)(kThetaMax/fDTheta); | |
421 | Int_t nCorrBand = (Int_t)(fWindowWidth/(2*fDTheta)); | |
422 | ||
423 | for (Int_t i=0; i< fPhotCnt; i++){//photon cadidates loop | |
424 | Double_t angle = fPhotCkov[i]; if(angle<0||angle>kThetaMax) continue; | |
425 | phots->Fill(angle); | |
426 | Int_t bin = (Int_t)(0.5+angle/(fDTheta)); | |
427 | Double_t weight=1.; | |
428 | if(fIsWEIGHT){ | |
afe12692 | 429 | Double_t lowerlimit = ((Double_t)bin)*fDTheta - 0.5*fDTheta; Double_t upperlimit = ((Double_t)bin)*fDTheta + 0.5*fDTheta; |
2d1a9b21 | 430 | FindRingGeom(lowerlimit); |
431 | Double_t areaLow = GetRingArea(); | |
432 | FindRingGeom(upperlimit); | |
433 | Double_t areaHigh = GetRingArea(); | |
434 | Double_t diffArea = areaHigh - areaLow; | |
d3da6dc4 | 435 | if(diffArea>0) weight = 1./diffArea; |
436 | } | |
437 | photsw->Fill(angle,weight); | |
438 | fPhotWei[i]=weight; | |
439 | }//photon candidates loop | |
440 | ||
441 | for (Int_t i=1; i<=nBin;i++){ | |
442 | Int_t bin1= i-nCorrBand; | |
443 | Int_t bin2= i+nCorrBand; | |
444 | if(bin1<1) bin1=1; | |
445 | if(bin2>nBin)bin2=nBin; | |
446 | Double_t sumPhots=phots->Integral(bin1,bin2); | |
447 | if(sumPhots<3) continue; // if less then 3 photons don't trust to this ring | |
448 | Double_t sumPhotsw=photsw->Integral(bin1,bin2); | |
449 | resultw->Fill((Double_t)((i+0.5)*fDTheta),sumPhotsw); | |
450 | } | |
451 | // evaluate the "BEST" theta ckov as the maximum value of histogramm | |
452 | Double_t *pVec = resultw->GetArray(); | |
453 | Int_t locMax = TMath::LocMax(nBin,pVec); | |
3ebd8038 | 454 | delete phots;delete photsw;delete resultw; // Reset and delete objects |
d3da6dc4 | 455 | |
456 | return (Double_t)(locMax*fDTheta+0.5*fDTheta); //final most probable track theta ckov | |
457 | }//HoughResponse() | |
458 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
459 | Double_t AliHMPIDRecon::Sigma2(Double_t ckovTh, Double_t ckovPh)const | |
460 | { | |
461 | // Analithical calculation of total error (as a sum of localization, geometrical and chromatic errors) on Cerenkov angle for a given Cerenkov photon | |
462 | // created by a given MIP. Fromulae according to CERN-EP-2000-058 | |
463 | // Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians] | |
464 | // dip and azimuthal angles for MIP taken at the entrance to radiator, [radians] | |
465 | // MIP beta | |
466 | // Returns: absolute error on Cerenkov angle, [radians] | |
467 | ||
468 | TVector3 v(-999,-999,-999); | |
ffb1ac19 | 469 | Double_t trkBeta = 1./(TMath::Cos(ckovTh)*fParam->GetRefIdx()); |
d3498bf5 | 470 | |
471 | if(trkBeta > 1) trkBeta = 1; //protection against bad measured thetaCer | |
472 | if(trkBeta < 0) trkBeta = 0.0001; // | |
d3da6dc4 | 473 | |
474 | v.SetX(SigLoc (ckovTh,ckovPh,trkBeta)); | |
475 | v.SetY(SigGeom(ckovTh,ckovPh,trkBeta)); | |
476 | v.SetZ(SigCrom(ckovTh,ckovPh,trkBeta)); | |
477 | ||
478 | return v.Mag2(); | |
479 | } | |
480 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
481 | Double_t AliHMPIDRecon::SigLoc(Double_t thetaC, Double_t phiC,Double_t betaM)const | |
482 | { | |
483 | // Analithical calculation of localization error (due to finite segmentation of PC) on Cerenkov angle for a given Cerenkov photon | |
484 | // created by a given MIP. Fromulae according to CERN-EP-2000-058 | |
485 | // Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians] | |
486 | // dip and azimuthal angles for MIP taken at the entrance to radiator, [radians] | |
487 | // MIP beta | |
488 | // Returns: absolute error on Cerenkov angle, [radians] | |
d3498bf5 | 489 | |
d3da6dc4 | 490 | Double_t phiDelta = phiC - fTrkDir.Phi(); |
491 | ||
d3498bf5 | 492 | Double_t sint = TMath::Sin(fTrkDir.Theta()); |
493 | Double_t cost = TMath::Cos(fTrkDir.Theta()); | |
494 | Double_t sinf = TMath::Sin(fTrkDir.Phi()); | |
495 | Double_t cosf = TMath::Cos(fTrkDir.Phi()); | |
496 | Double_t sinfd = TMath::Sin(phiDelta); | |
497 | Double_t cosfd = TMath::Cos(phiDelta); | |
498 | Double_t tantheta = TMath::Tan(thetaC); | |
499 | ||
500 | Double_t alpha =cost-tantheta*cosfd*sint; // formula (11) | |
ffb1ac19 | 501 | Double_t k = 1.-fParam->GetRefIdx()*fParam->GetRefIdx()+alpha*alpha/(betaM*betaM); // formula (after 8 in the text) |
d3da6dc4 | 502 | if (k<0) return 1e10; |
d3498bf5 | 503 | Double_t mu =sint*sinf+tantheta*(cost*cosfd*sinf+sinfd*cosf); // formula (10) |
504 | Double_t e =sint*cosf+tantheta*(cost*cosfd*cosf-sinfd*sinf); // formula (9) | |
d3da6dc4 | 505 | |
ffb1ac19 | 506 | Double_t kk = betaM*TMath::Sqrt(k)/(fParam->GapThick()*alpha); // formula (6) and (7) |
d3498bf5 | 507 | Double_t dtdxc = kk*(k*(cosfd*cosf-cost*sinfd*sinf)-(alpha*mu/(betaM*betaM))*sint*sinfd); // formula (6) |
508 | Double_t dtdyc = kk*(k*(cosfd*sinf+cost*sinfd*cosf)+(alpha* e/(betaM*betaM))*sint*sinfd); // formula (7) pag.4 | |
d3da6dc4 | 509 | |
d3498bf5 | 510 | Double_t errX = 0.2,errY=0.25; //end of page 7 |
511 | return TMath::Sqrt(errX*errX*dtdxc*dtdxc + errY*errY*dtdyc*dtdyc); | |
d3da6dc4 | 512 | } |
513 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
514 | Double_t AliHMPIDRecon::SigCrom(Double_t thetaC, Double_t phiC,Double_t betaM)const | |
515 | { | |
516 | // Analithical calculation of chromatic error (due to lack of knowledge of Cerenkov photon energy) on Cerenkov angle for a given Cerenkov photon | |
517 | // created by a given MIP. Fromulae according to CERN-EP-2000-058 | |
518 | // Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians] | |
519 | // dip and azimuthal angles for MIP taken at the entrance to radiator, [radians] | |
520 | // MIP beta | |
521 | // Returns: absolute error on Cerenkov angle, [radians] | |
d3498bf5 | 522 | |
d3da6dc4 | 523 | Double_t phiDelta = phiC - fTrkDir.Phi(); |
d3da6dc4 | 524 | |
d3498bf5 | 525 | Double_t sint = TMath::Sin(fTrkDir.Theta()); |
526 | Double_t cost = TMath::Cos(fTrkDir.Theta()); | |
527 | Double_t cosfd = TMath::Cos(phiDelta); | |
528 | Double_t tantheta = TMath::Tan(thetaC); | |
529 | ||
530 | Double_t alpha =cost-tantheta*cosfd*sint; // formula (11) | |
ffb1ac19 | 531 | Double_t dtdn = cost*fParam->GetRefIdx()*betaM*betaM/(alpha*tantheta); // formula (12) |
d3da6dc4 | 532 | |
d3498bf5 | 533 | // Double_t f = 0.00928*(7.75-5.635)/TMath::Sqrt(12.); |
534 | Double_t f = 0.0172*(7.75-5.635)/TMath::Sqrt(24.); | |
d3da6dc4 | 535 | |
536 | return f*dtdn; | |
537 | }//SigCrom() | |
538 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
539 | Double_t AliHMPIDRecon::SigGeom(Double_t thetaC, Double_t phiC,Double_t betaM)const | |
540 | { | |
541 | // Analithical calculation of geometric error (due to lack of knowledge of creation point in radiator) on Cerenkov angle for a given Cerenkov photon | |
542 | // created by a given MIP. Formulae according to CERN-EP-2000-058 | |
543 | // Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians] | |
544 | // dip and azimuthal angles for MIP taken at the entrance to radiator, [radians] | |
545 | // MIP beta | |
546 | // Returns: absolute error on Cerenkov angle, [radians] | |
547 | ||
548 | Double_t phiDelta = phiC - fTrkDir.Phi(); | |
d3da6dc4 | 549 | |
d3498bf5 | 550 | Double_t sint = TMath::Sin(fTrkDir.Theta()); |
551 | Double_t cost = TMath::Cos(fTrkDir.Theta()); | |
552 | Double_t sinf = TMath::Sin(fTrkDir.Phi()); | |
553 | Double_t cosfd = TMath::Cos(phiDelta); | |
554 | Double_t costheta = TMath::Cos(thetaC); | |
555 | Double_t tantheta = TMath::Tan(thetaC); | |
556 | ||
557 | Double_t alpha =cost-tantheta*cosfd*sint; // formula (11) | |
558 | ||
ffb1ac19 | 559 | Double_t k = 1.-fParam->GetRefIdx()*fParam->GetRefIdx()+alpha*alpha/(betaM*betaM); // formula (after 8 in the text) |
d3da6dc4 | 560 | if (k<0) return 1e10; |
561 | ||
ffb1ac19 | 562 | Double_t eTr = 0.5*fParam->RadThick()*betaM*TMath::Sqrt(k)/(fParam->GapThick()*alpha); // formula (14) |
d3498bf5 | 563 | Double_t lambda = 1.-sint*sint*sinf*sinf; // formula (15) |
d3da6dc4 | 564 | |
d3498bf5 | 565 | Double_t c1 = 1./(1.+ eTr*k/(alpha*alpha*costheta*costheta)); // formula (13.a) |
ffb1ac19 | 566 | Double_t c2 = betaM*TMath::Power(k,1.5)*tantheta*lambda/(fParam->GapThick()*alpha*alpha); // formula (13.b) |
d3498bf5 | 567 | Double_t c3 = (1.+eTr*k*betaM*betaM)/((1+eTr)*alpha*alpha); // formula (13.c) |
ffb1ac19 | 568 | Double_t c4 = TMath::Sqrt(k)*tantheta*(1-lambda)/(fParam->GapThick()*betaM); // formula (13.d) |
d3498bf5 | 569 | Double_t dtdT = c1 * (c2+c3*c4); |
ffb1ac19 | 570 | Double_t trErr = fParam->RadThick()/(TMath::Sqrt(12.)*cost); |
d3da6dc4 | 571 | |
d3498bf5 | 572 | return trErr*dtdT; |
d3da6dc4 | 573 | }//SigGeom() |