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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 |
25 | #include "AliHMPIDParam.h" //CkovAngle() | |
d3da6dc4 | 26 | #include "AliHMPIDCluster.h" //CkovAngle() |
a591e55f | 27 | #include <TRotation.h> //TracePhot() |
28 | #include <TH1D.h> //HoughResponse() | |
29 | #include <TClonesArray.h> //CkovAngle() | |
30 | #include <AliESDtrack.h> //CkovAngle() | |
d3da6dc4 | 31 | |
32 | const Double_t AliHMPIDRecon::fgkRadThick=1.5; | |
33 | const Double_t AliHMPIDRecon::fgkWinThick=0.5; | |
34 | const Double_t AliHMPIDRecon::fgkGapThick=8.0; | |
d3da6dc4 | 35 | const Double_t AliHMPIDRecon::fgkWinIdx =1.5787; |
36 | const Double_t AliHMPIDRecon::fgkGapIdx =1.0005; | |
37 | ||
d3da6dc4 | 38 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
39 | AliHMPIDRecon::AliHMPIDRecon():TTask("RichRec","RichPat"), | |
abb5f786 | 40 | fRadNmean(1.292), |
d3da6dc4 | 41 | fPhotCnt(-1), |
42 | fCkovSigma2(0), | |
43 | fIsWEIGHT(kFALSE), | |
44 | fDTheta(0.001), | |
45 | fWindowWidth(0.045), | |
46 | fTrkDir(TVector3(0,0,1)),fTrkPos(TVector2(30,40)) | |
47 | { | |
48 | // main ctor | |
49 | for (Int_t i=0; i<3000; i++) { | |
50 | fPhotFlag[i] = 0; | |
51 | fPhotCkov[i] = -1; | |
52 | fPhotPhi [i] = -1; | |
53 | fPhotWei [i] = 0; | |
54 | } | |
55 | } | |
56 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
a591e55f | 57 | void AliHMPIDRecon::CkovAngle(AliESDtrack *pTrk,TClonesArray *pCluLst,Double_t nmean) |
d3da6dc4 | 58 | { |
59 | // Pattern recognition method based on Hough transform | |
59280a5a | 60 | // Arguments: pTrk - track for which Ckov angle is to be found |
61 | // pCluLst - list of clusters for this chamber | |
62 | // Returns: - track ckov angle, [rad], | |
a591e55f | 63 | |
64 | AliHMPIDParam *pParam=AliHMPIDParam::Instance(); | |
d3da6dc4 | 65 | |
a591e55f | 66 | if(pCluLst->GetEntries()>pParam->MultCut()) fIsWEIGHT = kTRUE; // offset to take into account bkg in reconstruction |
67 | else fIsWEIGHT = kFALSE; | |
d3da6dc4 | 68 | |
a591e55f | 69 | Float_t xRa,yRa,th,ph; |
70 | pTrk->GetHMPIDtrk(xRa,yRa,th,ph); //initialize this track: th and ph angles at middle of RAD | |
a591e55f | 71 | SetTrack(xRa,yRa,th,ph); |
72 | ||
abb5f786 | 73 | fRadNmean=nmean; |
d3da6dc4 | 74 | |
59280a5a | 75 | Float_t dMin=999,mipX=-1,mipY=-1;Int_t chId=-1,mipId=-1,mipQ=-1; |
d3da6dc4 | 76 | fPhotCnt=0; |
77 | for (Int_t iClu=0; iClu<pCluLst->GetEntriesFast();iClu++){//clusters loop | |
78 | AliHMPIDCluster *pClu=(AliHMPIDCluster*)pCluLst->UncheckedAt(iClu); //get pointer to current cluster | |
59280a5a | 79 | chId=pClu->Ch(); |
a591e55f | 80 | if(pClu->Q()>pParam->QCut()){ //charge compartible with MIP clusters |
81 | 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 | |
82 | 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 | |
83 | }else{ //charge compatible with photon cluster | |
84 | Double_t thetaCer,phiCer; | |
85 | if(FindPhotCkov(pClu->X(),pClu->Y(),thetaCer,phiCer)){ //find ckov angle for this photon candidate | |
86 | fPhotCkov[fPhotCnt]=thetaCer; //actual theta Cerenkov (in TRS) | |
b4ad85e9 | 87 | fPhotPhi [fPhotCnt]=phiCer; //actual phi Cerenkov (in TRS): -pi to come back to "unusual" ref system (X,Y,-Z) |
a591e55f | 88 | fPhotCnt++; //increment counter of photon candidates |
89 | } | |
59280a5a | 90 | } |
d3da6dc4 | 91 | }//clusters loop |
a591e55f | 92 | Int_t iNacc=FlagPhot(HoughResponse()); //flag photons according to individual theta ckov with respect to most probable |
93 | pTrk->SetHMPIDmip(mipX,mipY,mipQ,iNacc); //store mip info | |
59280a5a | 94 | |
a591e55f | 95 | if(mipId==-1) {pTrk->SetHMPIDsignal(kMipQdcCut); return;} //no clusters with QDC more the threshold at all |
96 | if(dMin>pParam->DistCut()) {pTrk->SetHMPIDsignal(kMipDistCut); return;} //closest cluster with enough charge is still too far from intersection | |
97 | pTrk->SetHMPIDcluIdx(chId,mipId); //set index of cluster | |
98 | if(iNacc<1) pTrk->SetHMPIDsignal(kNoPhotAccept); //no photon candidates is accepted | |
99 | else pTrk->SetHMPIDsignal(FindRingCkov(pCluLst->GetEntries())); //find best Theta ckov for ring i.e. track | |
59280a5a | 100 | |
a591e55f | 101 | pTrk->SetHMPIDchi2(fCkovSigma2); //errors squared |
d3da6dc4 | 102 | |
d3da6dc4 | 103 | }//ThetaCerenkov() |
104 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
a591e55f | 105 | Bool_t AliHMPIDRecon::FindPhotCkov(Double_t cluX,Double_t cluY,Double_t &thetaCer,Double_t &phiCer) |
d3da6dc4 | 106 | { |
107 | // Finds Cerenkov angle for this photon candidate | |
108 | // Arguments: cluX,cluY - position of cadidate's cluster | |
a591e55f | 109 | // Returns: Cerenkov angle |
d3da6dc4 | 110 | |
a591e55f | 111 | TVector3 dirCkov; |
112 | ||
67a1c24c | 113 | Double_t zRad= -0.5*fgkRadThick-0.5*fgkWinThick; //z position of middle of RAD |
114 | TVector3 rad(fTrkPos.X(),fTrkPos.Y(),zRad); //impact point at middle of RAD | |
115 | TVector3 pc(cluX,cluY,0.5*fgkWinThick+fgkGapIdx); //mip at PC | |
a591e55f | 116 | Double_t cluR = TMath::Sqrt((cluX-fTrkPos.X())*(cluX-fTrkPos.X())+ |
117 | (cluY-fTrkPos.Y())*(cluY-fTrkPos.Y()));//ref. distance impact RAD-CLUSTER | |
67a1c24c | 118 | Double_t phi=(pc-rad).Phi(); //phi of photon |
a591e55f | 119 | |
b4ad85e9 | 120 | Double_t ckov1=0; |
67a1c24c | 121 | Double_t ckov2=0.75+fTrkDir.Theta(); //start to find theta cerenkov in DRS |
b4ad85e9 | 122 | const Double_t kTol=0.01; |
d3da6dc4 | 123 | Int_t iIterCnt = 0; |
124 | while(1){ | |
a591e55f | 125 | if(iIterCnt>=50) return kFALSE; |
d3da6dc4 | 126 | Double_t ckov=0.5*(ckov1+ckov2); |
67a1c24c | 127 | dirCkov.SetMagThetaPhi(1,ckov,phi); |
a591e55f | 128 | TVector2 posC=TraceForward(dirCkov); //trace photon with actual angles |
129 | Double_t dist=cluR-(posC-fTrkPos).Mod(); //get distance between trial point and cluster position | |
130 | if(posC.X()==-999) dist = - 999; //total reflection problem | |
131 | iIterCnt++; //counter step | |
b4ad85e9 | 132 | if (dist> kTol) ckov1=ckov; //cluster @ larger ckov |
d3da6dc4 | 133 | else if(dist<-kTol) ckov2=ckov; //cluster @ smaller ckov |
a591e55f | 134 | else{ //precision achived: ckov in DRS found |
135 | dirCkov.SetMagThetaPhi(1,ckov,phi); // | |
136 | RecPhot(dirCkov,thetaCer,phiCer); //find ckov (in TRS:the effective Cherenkov angle!) | |
137 | return kTRUE; | |
138 | } | |
d3da6dc4 | 139 | } |
140 | }//FindPhotTheta() | |
141 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
a591e55f | 142 | TVector2 AliHMPIDRecon::TraceForward(TVector3 dirCkov)const |
d3da6dc4 | 143 | { |
a591e55f | 144 | //Trace forward a photon from (x,y) up to PC |
145 | // Arguments: dirCkov photon vector in LORS | |
146 | // Returns: pos of traced photon at PC | |
147 | TVector2 pos(-999,-999); | |
67a1c24c | 148 | Double_t thetaCer = dirCkov.Theta(); |
149 | if(thetaCer > TMath::ASin(1./fRadNmean)) return pos; //total refraction on WIN-GAP boundary | |
150 | Double_t zRad= -0.5*fgkRadThick-0.5*fgkWinThick; //z position of middle of RAD | |
151 | TVector3 posCkov(fTrkPos.X(),fTrkPos.Y(),zRad); //RAD: photon position is track position @ middle of RAD | |
152 | Propagate(dirCkov,posCkov, -0.5*fgkWinThick); //go to RAD-WIN boundary | |
153 | Refract (dirCkov, fRadNmean,fgkWinIdx); //RAD-WIN refraction | |
154 | Propagate(dirCkov,posCkov, 0.5*fgkWinThick); //go to WIN-GAP boundary | |
155 | Refract (dirCkov, fgkWinIdx,fgkGapIdx); //WIN-GAP refraction | |
156 | Propagate(dirCkov,posCkov,0.5*fgkWinThick+fgkGapThick); //go to PC | |
a591e55f | 157 | pos.Set(posCkov.X(),posCkov.Y()); |
158 | return pos; | |
159 | }//TraceForward() | |
160 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
161 | void AliHMPIDRecon::RecPhot(TVector3 dirCkov,Double_t &thetaCer,Double_t &phiCer) | |
162 | { | |
163 | //Theta Cerenkov reconstruction | |
164 | // Arguments: (x,y) of initial point in LORS, dirCkov photon vector in LORS | |
165 | // Returns: thetaCer theta cerenkov reconstructed | |
166 | // TVector3 dirTrk; | |
167 | // dirTrk.SetMagThetaPhi(1,fTrkDir.Theta(),fTrkDir.Phi()); | |
168 | // Double_t thetaCer = TMath::ACos(dirCkov*dirTrk); | |
169 | TRotation mtheta; mtheta.RotateY(- fTrkDir.Theta()); | |
170 | TRotation mphi; mphi.RotateZ(- fTrkDir.Phi()); | |
171 | TRotation mrot=mtheta*mphi; | |
172 | TVector3 dirCkovTRS; | |
173 | dirCkovTRS=mrot*dirCkov; | |
174 | phiCer = dirCkovTRS.Phi(); //actual value of the phi of the photon | |
175 | thetaCer= dirCkovTRS.Theta(); //actual value of thetaCerenkov of the photon | |
d3da6dc4 | 176 | } |
177 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
178 | Double_t AliHMPIDRecon::FindRingArea(Double_t ckovAng)const | |
179 | { | |
180 | // Find area inside the cerenkov ring which lays inside PCs | |
a591e55f | 181 | // Arguments: ckovAng - cerenkov angle |
d3da6dc4 | 182 | // Returns: area of the ring in cm^2 for given theta ckov |
183 | ||
d3da6dc4 | 184 | const Int_t kN=100; |
185 | Double_t area=0; | |
186 | for(Int_t i=0;i<kN;i++){ | |
a591e55f | 187 | TVector2 pos1=TracePhot(ckovAng,Double_t(TMath::TwoPi()*i /kN));//trace this photon |
188 | TVector2 pos2=TracePhot(ckovAng,Double_t(TMath::TwoPi()*(i+1)/kN));//trace the next photon | |
189 | area+=(pos1-fTrkPos)*(pos2-fTrkPos); //add area of the triangle... | |
d3da6dc4 | 190 | } |
191 | return area; | |
192 | }//FindRingArea() | |
193 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
194 | Double_t AliHMPIDRecon::FindRingCkov(Int_t) | |
195 | { | |
196 | // 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 | |
197 | // collecting errors for all single Ckov candidates thetas. (Assuming they are independent) | |
198 | // Arguments: iNclus- total number of clusters in chamber for background estimation | |
199 | // Return: best estimation of track Theta ckov | |
200 | ||
201 | Double_t wei = 0.; | |
202 | Double_t weightThetaCerenkov = 0.; | |
203 | ||
204 | Double_t ckovMin=9999.,ckovMax=0.; | |
205 | Double_t sigma2 = 0; //to collect error squared for this ring | |
206 | ||
207 | for(Int_t i=0;i<fPhotCnt;i++){//candidates loop | |
208 | if(fPhotFlag[i] == 2){ | |
a591e55f | 209 | if(fPhotCkov[i]<ckovMin) ckovMin=fPhotCkov[i]; //find max and min Theta ckov from all candidates within probable window |
d3da6dc4 | 210 | if(fPhotCkov[i]>ckovMax) ckovMax=fPhotCkov[i]; |
a591e55f | 211 | weightThetaCerenkov += fPhotCkov[i]*fPhotWei[i]; |
212 | wei += fPhotWei[i]; //collect weight as sum of all candidate weghts | |
d3da6dc4 | 213 | |
d3da6dc4 | 214 | sigma2 += 1./Sigma2(fPhotCkov[i],fPhotPhi[i]); |
215 | } | |
216 | }//candidates loop | |
217 | ||
218 | if(sigma2>0) fCkovSigma2=1./sigma2; | |
219 | else fCkovSigma2=1e10; | |
220 | ||
b4ad85e9 | 221 | if(wei != 0.) weightThetaCerenkov /= wei; else weightThetaCerenkov = 0.; |
d3da6dc4 | 222 | return weightThetaCerenkov; |
223 | }//FindCkovRing() | |
224 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
225 | Int_t AliHMPIDRecon::FlagPhot(Double_t ckov) | |
226 | { | |
227 | // Flag photon candidates if their individual ckov angle is inside the window around ckov angle returned by HoughResponse() | |
228 | // Arguments: ckov- value of most probable ckov angle for track as returned by HoughResponse() | |
229 | // Returns: number of photon candidates happened to be inside the window | |
230 | ||
a591e55f | 231 | // Photon Flag: Flag = 0 initial set; |
232 | // Flag = 1 good candidate (charge compatible with photon); | |
233 | // Flag = 2 photon used for the ring; | |
d3da6dc4 | 234 | |
235 | Int_t steps = (Int_t)((ckov )/ fDTheta); //how many times we need to have fDTheta to fill the distance between 0 and thetaCkovHough | |
236 | ||
237 | Double_t tmin = (Double_t)(steps - 1)*fDTheta; | |
238 | Double_t tmax = (Double_t)(steps)*fDTheta; | |
239 | Double_t tavg = 0.5*(tmin+tmax); | |
240 | ||
241 | tmin = tavg - 0.5*fWindowWidth; tmax = tavg + 0.5*fWindowWidth; | |
242 | ||
243 | Int_t iInsideCnt = 0; //count photons which Theta ckov inside the window | |
244 | for(Int_t i=0;i<fPhotCnt;i++){//photon candidates loop | |
245 | if(fPhotCkov[i] >= tmin && fPhotCkov[i] <= tmax) { | |
246 | fPhotFlag[i]=2; | |
247 | iInsideCnt++; | |
248 | } | |
249 | } | |
250 | return iInsideCnt; | |
251 | }//FlagPhot() | |
252 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
a591e55f | 253 | TVector2 AliHMPIDRecon::TracePhot(Double_t ckovThe,Double_t ckovPhi)const |
d3da6dc4 | 254 | { |
255 | // Trace a single Ckov photon from emission point somewhere in radiator up to photocathode taking into account ref indexes of materials it travereses | |
a591e55f | 256 | // Arguments: ckovThe,ckovPhi- photon ckov angles in DRS, [rad] |
d3da6dc4 | 257 | // Returns: distance between photon point on PC and track projection |
258 | TRotation mtheta; mtheta.RotateY(fTrkDir.Theta()); | |
259 | TRotation mphi; mphi.RotateZ(fTrkDir.Phi()); | |
260 | TRotation mrot=mphi*mtheta; | |
a591e55f | 261 | TVector3 dirCkov,dirCkovTors; |
262 | ||
263 | dirCkovTors.SetMagThetaPhi(1,ckovThe,ckovPhi); //initially photon is directed according to requested ckov angle | |
264 | dirCkov=mrot*dirCkovTors; //now we know photon direction in LORS | |
265 | return TraceForward(dirCkov); | |
266 | }//TracePhot() | |
d3da6dc4 | 267 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
a591e55f | 268 | void AliHMPIDRecon::Propagate(const TVector3 dir,TVector3 &pos,Double_t z)const |
d3da6dc4 | 269 | { |
270 | // Finds an intersection point between a line and XY plane shifted along Z. | |
271 | // Arguments: dir,pos - vector along the line and any point of the line | |
272 | // z - z coordinate of plain | |
273 | // Returns: none | |
274 | // On exit: pos is the position if this intesection if any | |
275 | static TVector3 nrm(0,0,1); | |
276 | TVector3 pnt(0,0,z); | |
277 | ||
278 | TVector3 diff=pnt-pos; | |
279 | Double_t sint=(nrm*diff)/(nrm*dir); | |
280 | pos+=sint*dir; | |
281 | }//Propagate() | |
282 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
283 | void AliHMPIDRecon::Refract(TVector3 &dir,Double_t n1,Double_t n2)const | |
284 | { | |
285 | // Refract direction vector according to Snell law | |
286 | // Arguments: | |
287 | // n1 - ref idx of first substance | |
288 | // n2 - ref idx of second substance | |
289 | // Returns: none | |
290 | // On exit: dir is new direction | |
67a1c24c | 291 | Double_t sinref=(n1/n2)*TMath::Sin(dir.Theta()); |
d3da6dc4 | 292 | if(sinref>1.) dir.SetXYZ(-999,-999,-999); |
67a1c24c | 293 | else dir.SetTheta(TMath::ASin(sinref)); |
d3da6dc4 | 294 | }//Refract() |
295 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
296 | Double_t AliHMPIDRecon::HoughResponse() | |
297 | { | |
298 | // | |
299 | // | |
300 | // | |
301 | Double_t kThetaMax=0.75; | |
302 | Int_t nChannels = (Int_t)(kThetaMax/fDTheta+0.5); | |
303 | TH1D *phots = new TH1D("Rphot" ,"phots" ,nChannels,0,kThetaMax); | |
304 | TH1D *photsw = new TH1D("RphotWeighted" ,"photsw" ,nChannels,0,kThetaMax); | |
305 | TH1D *resultw = new TH1D("resultw","resultw" ,nChannels,0,kThetaMax); | |
306 | Int_t nBin = (Int_t)(kThetaMax/fDTheta); | |
307 | Int_t nCorrBand = (Int_t)(fWindowWidth/(2*fDTheta)); | |
308 | ||
309 | for (Int_t i=0; i< fPhotCnt; i++){//photon cadidates loop | |
310 | Double_t angle = fPhotCkov[i]; if(angle<0||angle>kThetaMax) continue; | |
311 | phots->Fill(angle); | |
312 | Int_t bin = (Int_t)(0.5+angle/(fDTheta)); | |
313 | Double_t weight=1.; | |
314 | if(fIsWEIGHT){ | |
315 | Double_t lowerlimit = ((Double_t)bin)*fDTheta - 0.5*fDTheta; Double_t upperlimit = ((Double_t)bin)*fDTheta + 0.5*fDTheta; | |
316 | Double_t diffArea = FindRingArea(upperlimit)-FindRingArea(lowerlimit); | |
317 | if(diffArea>0) weight = 1./diffArea; | |
318 | } | |
319 | photsw->Fill(angle,weight); | |
320 | fPhotWei[i]=weight; | |
321 | }//photon candidates loop | |
322 | ||
323 | for (Int_t i=1; i<=nBin;i++){ | |
324 | Int_t bin1= i-nCorrBand; | |
325 | Int_t bin2= i+nCorrBand; | |
326 | if(bin1<1) bin1=1; | |
327 | if(bin2>nBin)bin2=nBin; | |
328 | Double_t sumPhots=phots->Integral(bin1,bin2); | |
329 | if(sumPhots<3) continue; // if less then 3 photons don't trust to this ring | |
330 | Double_t sumPhotsw=photsw->Integral(bin1,bin2); | |
331 | resultw->Fill((Double_t)((i+0.5)*fDTheta),sumPhotsw); | |
332 | } | |
333 | // evaluate the "BEST" theta ckov as the maximum value of histogramm | |
334 | Double_t *pVec = resultw->GetArray(); | |
335 | Int_t locMax = TMath::LocMax(nBin,pVec); | |
336 | phots->Delete();photsw->Delete();resultw->Delete(); // Reset and delete objects | |
337 | ||
338 | return (Double_t)(locMax*fDTheta+0.5*fDTheta); //final most probable track theta ckov | |
339 | }//HoughResponse() | |
340 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
341 | Double_t AliHMPIDRecon::Sigma2(Double_t ckovTh, Double_t ckovPh)const | |
342 | { | |
343 | // Analithical calculation of total error (as a sum of localization, geometrical and chromatic errors) on Cerenkov angle for a given Cerenkov photon | |
344 | // created by a given MIP. Fromulae according to CERN-EP-2000-058 | |
345 | // Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians] | |
346 | // dip and azimuthal angles for MIP taken at the entrance to radiator, [radians] | |
347 | // MIP beta | |
348 | // Returns: absolute error on Cerenkov angle, [radians] | |
349 | ||
350 | TVector3 v(-999,-999,-999); | |
abb5f786 | 351 | Double_t trkBeta = 1./(TMath::Cos(ckovTh)*fRadNmean); |
d3da6dc4 | 352 | |
353 | v.SetX(SigLoc (ckovTh,ckovPh,trkBeta)); | |
354 | v.SetY(SigGeom(ckovTh,ckovPh,trkBeta)); | |
355 | v.SetZ(SigCrom(ckovTh,ckovPh,trkBeta)); | |
356 | ||
357 | return v.Mag2(); | |
358 | } | |
359 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
360 | Double_t AliHMPIDRecon::SigLoc(Double_t thetaC, Double_t phiC,Double_t betaM)const | |
361 | { | |
362 | // Analithical calculation of localization error (due to finite segmentation of PC) on Cerenkov angle for a given Cerenkov photon | |
363 | // created by a given MIP. Fromulae according to CERN-EP-2000-058 | |
364 | // Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians] | |
365 | // dip and azimuthal angles for MIP taken at the entrance to radiator, [radians] | |
366 | // MIP beta | |
367 | // Returns: absolute error on Cerenkov angle, [radians] | |
368 | Double_t phiDelta = phiC - fTrkDir.Phi(); | |
369 | ||
370 | Double_t alpha =TMath::Cos(fTrkDir.Theta())-TMath::Tan(thetaC)*TMath::Cos(phiDelta)*TMath::Sin(fTrkDir.Theta()); | |
abb5f786 | 371 | Double_t k = 1.-fRadNmean*fRadNmean+alpha*alpha/(betaM*betaM); |
d3da6dc4 | 372 | if (k<0) return 1e10; |
373 | ||
374 | Double_t mu =TMath::Sin(fTrkDir.Theta())*TMath::Sin(fTrkDir.Phi())+TMath::Tan(thetaC)*(TMath::Cos(fTrkDir.Theta())*TMath::Cos(phiDelta)*TMath::Sin(fTrkDir.Phi())+TMath::Sin(phiDelta)*TMath::Cos(fTrkDir.Phi())); | |
375 | Double_t e =TMath::Sin(fTrkDir.Theta())*TMath::Cos(fTrkDir.Phi())+TMath::Tan(thetaC)*(TMath::Cos(fTrkDir.Theta())*TMath::Cos(phiDelta)*TMath::Cos(fTrkDir.Phi())-TMath::Sin(phiDelta)*TMath::Sin(fTrkDir.Phi())); | |
376 | ||
377 | Double_t kk = betaM*TMath::Sqrt(k)/(8*alpha); | |
378 | Double_t dtdxc = kk*(k*(TMath::Cos(phiDelta)*TMath::Cos(fTrkDir.Phi())-TMath::Cos(fTrkDir.Theta())*TMath::Sin(phiDelta)*TMath::Sin(fTrkDir.Phi()))-(alpha*mu/(betaM*betaM))*TMath::Sin(fTrkDir.Theta())*TMath::Sin(phiDelta)); | |
379 | Double_t dtdyc = kk*(k*(TMath::Cos(phiDelta)*TMath::Sin(fTrkDir.Phi())+TMath::Cos(fTrkDir.Theta())*TMath::Sin(phiDelta)*TMath::Cos(fTrkDir.Phi()))+(alpha* e/(betaM*betaM))*TMath::Sin(fTrkDir.Theta())*TMath::Sin(phiDelta)); | |
380 | ||
381 | return TMath::Sqrt(0.2*0.2*dtdxc*dtdxc + 0.25*0.25*dtdyc*dtdyc); | |
382 | } | |
383 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
384 | Double_t AliHMPIDRecon::SigCrom(Double_t thetaC, Double_t phiC,Double_t betaM)const | |
385 | { | |
386 | // Analithical calculation of chromatic error (due to lack of knowledge of Cerenkov photon energy) on Cerenkov angle for a given Cerenkov photon | |
387 | // created by a given MIP. Fromulae according to CERN-EP-2000-058 | |
388 | // Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians] | |
389 | // dip and azimuthal angles for MIP taken at the entrance to radiator, [radians] | |
390 | // MIP beta | |
391 | // Returns: absolute error on Cerenkov angle, [radians] | |
392 | Double_t phiDelta = phiC - fTrkDir.Phi(); | |
393 | Double_t alpha =TMath::Cos(fTrkDir.Theta())-TMath::Tan(thetaC)*TMath::Cos(phiDelta)*TMath::Sin(fTrkDir.Theta()); | |
394 | ||
abb5f786 | 395 | Double_t dtdn = TMath::Cos(fTrkDir.Theta())*fRadNmean*betaM*betaM/(alpha*TMath::Tan(thetaC)); |
d3da6dc4 | 396 | |
397 | Double_t f = 0.00928*(7.75-5.635)/TMath::Sqrt(12.); | |
398 | ||
399 | return f*dtdn; | |
400 | }//SigCrom() | |
401 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ | |
402 | Double_t AliHMPIDRecon::SigGeom(Double_t thetaC, Double_t phiC,Double_t betaM)const | |
403 | { | |
404 | // Analithical calculation of geometric error (due to lack of knowledge of creation point in radiator) on Cerenkov angle for a given Cerenkov photon | |
405 | // created by a given MIP. Formulae according to CERN-EP-2000-058 | |
406 | // Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians] | |
407 | // dip and azimuthal angles for MIP taken at the entrance to radiator, [radians] | |
408 | // MIP beta | |
409 | // Returns: absolute error on Cerenkov angle, [radians] | |
410 | ||
411 | Double_t phiDelta = phiC - fTrkDir.Phi(); | |
412 | Double_t alpha =TMath::Cos(fTrkDir.Theta())-TMath::Tan(thetaC)*TMath::Cos(phiDelta)*TMath::Sin(fTrkDir.Theta()); | |
413 | ||
abb5f786 | 414 | Double_t k = 1.-fRadNmean*fRadNmean+alpha*alpha/(betaM*betaM); |
d3da6dc4 | 415 | if (k<0) return 1e10; |
416 | ||
417 | Double_t eTr = 0.5*1.5*betaM*TMath::Sqrt(k)/(8*alpha); | |
418 | Double_t lambda = 1.-TMath::Sin(fTrkDir.Theta())*TMath::Sin(fTrkDir.Theta())*TMath::Sin(phiC)*TMath::Sin(phiC); | |
419 | ||
420 | Double_t c = 1./(1.+ eTr*k/(alpha*alpha*TMath::Cos(thetaC)*TMath::Cos(thetaC))); | |
421 | Double_t i = betaM*TMath::Tan(thetaC)*lambda*TMath::Power(k,1.5); | |
422 | Double_t ii = 1.+eTr*betaM*i; | |
423 | ||
424 | Double_t err = c * (i/(alpha*alpha*8) + ii*(1.-lambda) / ( alpha*alpha*8*betaM*(1.+eTr)) ); | |
425 | Double_t trErr = 1.5/(TMath::Sqrt(12.)*TMath::Cos(fTrkDir.Theta())); | |
426 | ||
427 | return trErr*err; | |
428 | }//SigGeom() | |
429 | //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |