Bug corrected.
[u/mrichter/AliRoot.git] / STEER / STEERBase / AliHMPIDPIDResponse.cxx
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15
16 //***********************************************************
17 // Class AliHMPIDPIDResponse
18 //
19 // HMPID class to perfom particle identification
20 // 
21 // Author: G. Volpe, giacomo.volpe@cern.ch
22 //***********************************************************
23
24
25 #include "AliHMPIDPIDResponse.h"  //class header
26 #include "AliPID.h"               //FindPid()
27 #include "AliVTrack.h"            //FindPid()
28 #include "AliLog.h"               //general
29 #include <TRandom.h>              //Resolution()
30 #include <TVector2.h>             //Resolution()
31 #include <TRotation.h>
32 #include <TF1.h>
33 #include <TGeoManager.h>          //Instance()
34 #include <TGeoMatrix.h>           //Instance()
35 #include <TGeoPhysicalNode.h>     //ctor
36 #include <TGeoBBox.h>
37 #include <TObjArray.h>
38
39 Float_t AliHMPIDPIDResponse::fgkMinPcX[]={0.,0.,0.,0.,0.,0.};
40 Float_t AliHMPIDPIDResponse::fgkMaxPcX[]={0.,0.,0.,0.,0.,0.};
41 Float_t AliHMPIDPIDResponse::fgkMinPcY[]={0.,0.,0.,0.,0.,0.};
42 Float_t AliHMPIDPIDResponse::fgkMaxPcY[]={0.,0.,0.,0.,0.,0.};
43
44 Float_t AliHMPIDPIDResponse::fgCellX=0.;
45 Float_t AliHMPIDPIDResponse::fgCellY=0.;
46
47 Float_t AliHMPIDPIDResponse::fgPcX=0;
48 Float_t AliHMPIDPIDResponse::fgPcY=0;
49
50 Float_t AliHMPIDPIDResponse::fgAllX=0;
51 Float_t AliHMPIDPIDResponse::fgAllY=0;
52
53 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
54 AliHMPIDPIDResponse::AliHMPIDPIDResponse():
55   TNamed("HMPIDPIDResponseRec","HMPIDPIDResponsePid"),    
56   fRefIdx(1.28947),
57   fTrkDir(0,0,1),  
58   fTrkPos(30,40),  
59   fRefIndexArray(0x0)
60 {
61   //
62   // ctor
63   //
64   
65   Float_t dead=2.6;// cm of the dead zones between PCs-> See 2CRC2099P1
66
67   fgCellX=0.8; fgCellY=0.84;
68   
69   fgPcX  = 80.*fgCellX;      fgPcY = 48.*fgCellY;
70   fgAllX = 2.*fgPcX+dead;
71   fgAllY = 3.*fgPcY+2.*dead;
72
73   fgkMinPcX[1]=fgPcX+dead; fgkMinPcX[3]=fgkMinPcX[1];  fgkMinPcX[5]=fgkMinPcX[3];
74   fgkMaxPcX[0]=fgPcX;      fgkMaxPcX[2]=fgkMaxPcX[0];  fgkMaxPcX[4]=fgkMaxPcX[2];
75   fgkMaxPcX[1]=fgAllX;     fgkMaxPcX[3]=fgkMaxPcX[1];  fgkMaxPcX[5]=fgkMaxPcX[3];
76
77   fgkMinPcY[2]=fgPcY+dead;       fgkMinPcY[3]=fgkMinPcY[2];  
78   fgkMinPcY[4]=2.*fgPcY+2.*dead; fgkMinPcY[5]=fgkMinPcY[4];
79   fgkMaxPcY[0]=fgPcY;            fgkMaxPcY[1]=fgkMaxPcY[0];  
80   fgkMaxPcY[2]=2.*fgPcY+dead;    fgkMaxPcY[3]=fgkMaxPcY[2]; 
81   fgkMaxPcY[4]=fgAllY;           fgkMaxPcY[5]=fgkMaxPcY[4];   
82     
83   for(Int_t i=kMinCh;i<=kMaxCh;i++)
84     if(gGeoManager && gGeoManager->IsClosed()) {
85       TGeoPNEntry* pne = gGeoManager->GetAlignableEntry(Form("/HMPID/Chamber%i",i));
86       if (!pne) {
87         AliErrorClass(Form("The symbolic volume %s does not correspond to any physical entry!",Form("HMPID_%i",i)));
88         fM[i]=new TGeoHMatrix;
89         IdealPosition(i,fM[i]);
90       } else {
91         TGeoPhysicalNode *pnode = pne->GetPhysicalNode();
92         if(pnode) fM[i]=new TGeoHMatrix(*(pnode->GetMatrix()));
93         else {
94           fM[i]=new TGeoHMatrix;
95           IdealPosition(i,fM[i]);
96         }
97       }
98     } else{
99       fM[i]=new TGeoHMatrix;
100       IdealPosition(i,fM[i]);
101     } 
102     
103 }//ctor
104 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
105 AliHMPIDPIDResponse::AliHMPIDPIDResponse(const AliHMPIDPIDResponse& c):
106   TNamed(c), 
107   fRefIdx(c.fRefIdx),
108   fTrkDir(c.fTrkDir),  
109   fTrkPos(c.fTrkPos),  
110   fRefIndexArray(c.fRefIndexArray)
111  {
112    //
113    // copy ctor
114    //
115    
116    for(Int_t i=0; i<6; i++) {
117       
118       fgkMinPcX[i] = c.fgkMinPcX[i];
119       fgkMinPcY[i] = c.fgkMinPcY[i];
120       fgkMaxPcX[i] = c.fgkMaxPcX[i];
121       fgkMaxPcY[i] = c.fgkMaxPcY[i];
122      }
123    
124    for(Int_t i=0; i<7; i++) fM[i] = c.fM[i] ? new TGeoHMatrix(*c.fM[i]) : 0;
125  }
126 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
127 AliHMPIDPIDResponse::~AliHMPIDPIDResponse()
128 {
129   // d-tor
130   for (int i=7;i--;) delete fM[i];
131 }
132
133 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
134 AliHMPIDPIDResponse& AliHMPIDPIDResponse::operator=(const AliHMPIDPIDResponse& c) {
135
136    //
137    // assignment operator
138    //       
139   if(this!=&c){
140      TNamed::operator=(c);
141      fgCellX = c.fgCellX;
142      fgCellY = c.fgCellY;
143      fgPcX   = c.fgPcX;
144      fgPcY   = c.fgPcY;
145      fgAllX  = c.fgAllX;
146      fgAllY  = c.fgAllY;
147      fRefIdx = c.fRefIdx;
148      fTrkDir = c.fTrkDir;  
149      fTrkPos = c.fTrkPos;  
150      fRefIndexArray = c.fRefIndexArray;
151      for(Int_t i=0; i<6; i++) {    
152       fgkMinPcX[i] = c.fgkMinPcX[i];
153       fgkMinPcY[i] = c.fgkMinPcY[i];
154       fgkMaxPcX[i] = c.fgkMaxPcX[i];
155       fgkMaxPcY[i] = c.fgkMaxPcY[i];
156      }   
157      for(Int_t i=0; i<7; i++) fM[i] = c.fM[i] ? new TGeoHMatrix(*c.fM[i]) : 0;
158     } 
159     
160   return *this; 
161 }    
162 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
163 void AliHMPIDPIDResponse::IdealPosition(Int_t iCh, TGeoHMatrix *pMatrix) {
164
165 // Construct ideal position matrix for a given chamber
166 // Arguments: iCh- chamber ID; pMatrix- pointer to precreated unity matrix where to store the results
167 // Returns: none
168
169   const Double_t kAngHor=19.5;        //  horizontal angle between chambers  19.5 grad
170   const Double_t kAngVer=20;          //  vertical angle between chambers    20   grad     
171   const Double_t kAngCom=30;          //  common HMPID rotation with respect to x axis  30   grad     
172   const Double_t kTrans[3]={490,0,0}; //  center of the chamber is on window-gap surface
173   pMatrix->RotateY(90);               //  rotate around y since initial position is in XY plane -> now in YZ plane
174   pMatrix->SetTranslation(kTrans);    //  now plane in YZ is shifted along x 
175   switch(iCh){
176     case 0:                pMatrix->RotateY(kAngHor);  pMatrix->RotateZ(-kAngVer);  break; //right and down 
177     case 1:                                            pMatrix->RotateZ(-kAngVer);  break; //down              
178     case 2:                pMatrix->RotateY(kAngHor);                               break; //right 
179     case 3:                                                                         break; //no rotation
180     case 4:                pMatrix->RotateY(-kAngHor);                              break; //left   
181     case 5:                                            pMatrix->RotateZ(kAngVer);   break; //up
182     case 6:                pMatrix->RotateY(-kAngHor); pMatrix->RotateZ(kAngVer);   break; //left and up 
183   }
184   pMatrix->RotateZ(kAngCom);     //apply common rotation  in XY plane    
185    
186 }
187 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
188 Double_t AliHMPIDPIDResponse::GetExpectedSignal(const AliVTrack *vTrk, AliPID::EParticleType specie) const {
189   
190   // expected Cherenkov angle calculation
191   
192   const Double_t nmean = GetNMean(vTrk);
193   return ExpectedSignal(vTrk,nmean,specie);
194 }
195 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
196 Double_t AliHMPIDPIDResponse::GetExpectedSigma(const AliVTrack *vTrk, AliPID::EParticleType specie) const {
197   
198   // expected resolution calculation
199   
200   const Double_t nmean = GetNMean(vTrk);
201   return ExpectedSigma(vTrk,nmean,specie);
202 }
203 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
204 Double_t AliHMPIDPIDResponse::ExpectedSignal(const AliVTrack *vTrk, Double_t nmean, AliPID::EParticleType specie) const {
205   
206   // expected Cherenkov angle calculation
207   
208   Double_t thetaTheor = -999.;
209   
210   Double_t p[3] = {0}, mom = 0;
211   if(vTrk->GetOuterHmpPxPyPz(p))  mom = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]+p[2]*p[2]);  // Momentum of the charged particle    
212   else return thetaTheor;
213     
214   const Double_t mass = AliPID::ParticleMass(specie); 
215   const Double_t cosTheta = TMath::Sqrt(mass*mass+mom*mom)/(nmean*mom);
216    
217   if(cosTheta>1) return thetaTheor;
218                   
219   else thetaTheor = TMath::ACos(cosTheta);
220   
221   return thetaTheor;                                                                                          //  evaluate the theor. Theta Cherenkov
222 }
223 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
224 Double_t AliHMPIDPIDResponse::ExpectedSigma(const AliVTrack *vTrk, Double_t nmean, AliPID::EParticleType specie) const {
225   
226   // expected resolution calculation
227   
228   Float_t x=0., y=0.;
229   Int_t q=0, nph=0;
230   Float_t xPc=0.,yPc=0.,thRa=0.,phRa=0.;
231   
232   vTrk->GetHMPIDmip(x,y,q,nph);  
233   vTrk->GetHMPIDtrk(xPc,yPc,thRa,phRa);
234       
235   const Double_t xRa = xPc - (RadThick()+WinThick()+GapThick())*TMath::Cos(phRa)*TMath::Tan(thRa);  //just linear extrapolation back to RAD
236   const Double_t yRa = yPc - (RadThick()+WinThick()+GapThick())*TMath::Sin(phRa)*TMath::Tan(thRa);  //just linear extrapolation back to RAD
237   
238   const Double_t thetaCerTh = ExpectedSignal(vTrk,nmean,specie);
239   const Double_t occupancy  = vTrk->GetHMPIDoccupancy();
240   const Double_t thetaMax   = TMath::ACos(1./nmean);
241   const Int_t    nPhotsTh   = (Int_t)(12.*TMath::Sin(thetaCerTh)*TMath::Sin(thetaCerTh)/(TMath::Sin(thetaMax)*TMath::Sin(thetaMax))+0.01);
242
243   Double_t sigmatot = 0;
244   Int_t nTrks = 20;
245   for(Int_t iTrk=0;iTrk<nTrks;iTrk++) {
246     Double_t invSigma = 0;
247     Int_t nPhotsAcc = 0;
248     
249     Int_t nPhots = 0; 
250     if(nph<nPhotsTh+TMath::Sqrt(nPhotsTh) && nph>nPhotsTh-TMath::Sqrt(nPhotsTh)) nPhots = nph;
251     else nPhots = gRandom->Poisson(nPhotsTh);
252     
253     for(Int_t j=0;j<nPhots;j++){
254       Double_t phi = gRandom->Rndm()*TMath::TwoPi();
255       TVector2 pos; pos = TracePhot(xRa,yRa,thRa,phRa,thetaCerTh,phi);
256       if(!IsInside(pos.X(),pos.Y())) continue;
257       if(IsInDead(pos.X(),pos.Y()))  continue;
258       Double_t sigma2 = Sigma2(thRa,phRa,thetaCerTh,phi); //photon candidate sigma^2
259       
260       if(sigma2!=0) {
261         invSigma += 1./sigma2;
262         nPhotsAcc++;
263       }
264     }      
265     if(invSigma!=0) sigmatot += 1./TMath::Sqrt(invSigma);  
266   }
267     
268   return (sigmatot/nTrks)*SigmaCorrFact(specie,occupancy);
269 }
270 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
271 Double_t AliHMPIDPIDResponse::GetNumberOfSigmas(const AliVTrack *vTrk, AliPID::EParticleType specie) const {
272
273   // Number of sigmas calculation
274     
275   Double_t nSigmas = -999.;
276
277   if(vTrk->GetHMPIDsignal()<0.) return nSigmas;
278     
279   const Double_t nmean = GetNMean(vTrk);
280   
281   const Double_t expSigma = ExpectedSigma(vTrk, nmean, specie);
282   
283   if(expSigma > 0.) nSigmas = (vTrk->GetHMPIDsignal() - ExpectedSignal(vTrk,nmean,specie))/expSigma;
284                          
285   return nSigmas;
286     
287 }
288 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
289 void AliHMPIDPIDResponse::GetProbability(const AliVTrack *vTrk,Int_t nSpecies,Double_t *prob) const {
290
291 // Calculates probability to be a electron-muon-pion-kaon-proton with the "amplitude" method
292 // from the given Cerenkov angle and momentum assuming no initial particle composition
293   
294   const Double_t thetaCerExp = vTrk->GetHMPIDsignal();                                                                           
295
296   const Double_t nmean = GetNMean(vTrk);
297     
298   if(thetaCerExp<=0){                                                                                     // HMPID does not find anything reasonable for this track, assign 0.2 for all species
299     for(Int_t iPart=0;iPart<nSpecies;iPart++) prob[iPart]=1.0/(Float_t)nSpecies;
300     return;
301   } 
302   
303   Double_t p[3] = {0,0,0};
304   
305   if(!(vTrk->GetOuterHmpPxPyPz(p))) for(Int_t iPart=0;iPart<nSpecies;iPart++) prob[iPart]=1.0/(Float_t)nSpecies;
306   
307   Double_t hTot=0;                                                                                        // Initialize the total height of the amplitude method
308   Double_t *h = new Double_t [nSpecies];                                                                  // number of charged particles to be considered
309
310   Bool_t desert = kTRUE;                                                                                  // Flag to evaluate if ThetaC is far ("desert") from the given Gaussians
311   
312   for(Int_t iPart=0;iPart<nSpecies;iPart++){                                                              // for each particle
313
314         
315     h[iPart] = 0;                                                                                         // reset the height
316     Double_t thetaCerTh = ExpectedSignal(vTrk,nmean,(AliPID::EParticleType)iPart);                        // theoretical Theta Cherenkov
317     if(thetaCerTh>900.) continue;                                                                         // no light emitted, zero height
318     Double_t sigmaRing = ExpectedSigma(vTrk,nmean,(AliPID::EParticleType)iPart);
319     
320     if(sigmaRing==0) continue;
321       
322     if(TMath::Abs(thetaCerExp-thetaCerTh)<4*sigmaRing) desert = kFALSE;                                                               
323     h[iPart] =TMath::Gaus(thetaCerTh,thetaCerExp,sigmaRing,kTRUE);
324     hTot    +=h[iPart];                                                                                   // total height of all theoretical heights for normalization
325     
326   }//species loop
327
328   for(Int_t iPart=0;iPart<nSpecies;iPart++) {                                                             // species loop to assign probabilities
329      
330     if(!desert) prob[iPart]=h[iPart]/hTot;
331     else        prob[iPart]=1.0/(Float_t)nSpecies;                                                        // all theoretical values are far away from experemental one
332     
333   }
334   
335   delete [] h;
336 }
337 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
338 Double_t AliHMPIDPIDResponse::GetSignalDelta(const AliVTrack *vTrk, AliPID::EParticleType specie, Bool_t ratio/*=kFALSE*/) const {
339   
340   //
341   // calculation of Experimental Cherenkov angle - Theoretical Cherenkov angle  
342   //
343   const Double_t signal    = vTrk->GetHMPIDsignal();
344   const Double_t expSignal = GetExpectedSignal(vTrk,specie);
345
346   Double_t delta = -9999.;
347   if (!ratio) delta=signal-expSignal;
348   else if (expSignal>1.e-20) delta=signal/expSignal;
349   
350   return delta;
351 }
352 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
353 TVector2 AliHMPIDPIDResponse::TracePhot(Double_t xRa, Double_t yRa, Double_t thRa, Double_t phRa, Double_t ckovThe,Double_t ckovPhi) const {
354
355 // Trace a single Ckov photon from emission point somewhere in radiator up to photocathode taking into account ref indexes of materials it travereses
356 // Returns: distance between photon point on PC and track projection  
357   
358   Double_t theta=0.,phi=0.;
359   TVector3  dirTRS,dirLORS;
360   dirTRS.SetMagThetaPhi(1,ckovThe,ckovPhi);                     //photon in TRS
361   Trs2Lors(thRa,phRa,dirTRS,theta,phi);
362   dirLORS.SetMagThetaPhi(1,theta,phi);                          //photon in LORS
363   return TraceForward(xRa,yRa,dirLORS);                                 //now foward tracing
364 }//TracePhot()
365 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
366 TVector2 AliHMPIDPIDResponse::TraceForward(Double_t xRa, Double_t yRa, TVector3 dirCkov) const {
367
368 // Trace forward a photon from (x,y) up to PC
369 // Returns: pos of traced photon at PC
370   
371   TVector2 pos(-999,-999);
372   Double_t thetaCer = dirCkov.Theta();
373   if(thetaCer > TMath::ASin(1./GetRefIdx())) return pos;          //total refraction on WIN-GAP boundary
374   Double_t zRad= -0.5*RadThick()-0.5*WinThick();          //z position of middle of RAD
375   TVector3  posCkov(xRa,yRa,zRad);                        //RAD: photon position is track position @ middle of RAD 
376   Propagate(dirCkov,posCkov,           -0.5*WinThick());          //go to RAD-WIN boundary  
377   Refract  (dirCkov,         GetRefIdx(),WinIdx());       //RAD-WIN refraction
378   Propagate(dirCkov,posCkov,            0.5*WinThick());          //go to WIN-GAP boundary
379   Refract  (dirCkov,         WinIdx(),GapIdx());          //WIN-GAP refraction
380   Propagate(dirCkov,posCkov,0.5*WinThick()+GapThick());   //go to PC
381   pos.Set(posCkov.X(),posCkov.Y());
382   return pos;
383 }//TraceForward()
384 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
385 void AliHMPIDPIDResponse::Propagate(const TVector3 dir,TVector3 &pos,Double_t z) const {
386   
387 // Finds an intersection point between a line and XY plane shifted along Z.
388 // Arguments:  dir,pos   - vector along the line and any point of the line
389 //             z         - z coordinate of plain 
390 // Returns:  none
391 // On exit:  pos is the position if this intesection if any
392
393   static TVector3 nrm(0,0,1); 
394          TVector3 pnt(0,0,z);
395   
396   TVector3 diff=pnt-pos;
397   Double_t sint=(nrm*diff)/(nrm*dir);
398   pos+=sint*dir;
399 }//Propagate()
400 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
401 void AliHMPIDPIDResponse::Refract(TVector3 &dir,Double_t n1,Double_t n2) const {
402
403 // Refract direction vector according to Snell law
404 // Arguments: 
405 //            n1 - ref idx of first substance
406 //            n2 - ref idx of second substance
407 //   Returns: none
408 //   On exit: dir is new direction
409   
410   Double_t sinref=(n1/n2)*TMath::Sin(dir.Theta());
411   if(TMath::Abs(sinref)>1.) dir.SetXYZ(-999,-999,-999);
412   else             dir.SetTheta(TMath::ASin(sinref));
413 }//Refract()
414 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
415 void AliHMPIDPIDResponse::Trs2Lors(Double_t thRa, Double_t phRa, TVector3 dirCkov,Double_t &thetaCer,Double_t &phiCer) const {
416
417   // Theta Cerenkov reconstruction 
418   // Returns: thetaCer of photon in LORS
419   //          phiCer of photon in LORS
420   
421   TRotation mtheta;   mtheta.RotateY(thRa);
422   TRotation mphi;       mphi.RotateZ(phRa);
423   TRotation mrot=mphi*mtheta;
424   TVector3 dirCkovLORS;
425   dirCkovLORS=mrot*dirCkov;
426   phiCer  = dirCkovLORS.Phi();                                          //actual value of the phi of the photon
427   thetaCer= dirCkovLORS.Theta();                                        //actual value of thetaCerenkov of the photon
428 }
429 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
430 Bool_t AliHMPIDPIDResponse::IsInDead(Float_t x,Float_t y)  {
431   
432 // Check is the current point is outside of sensitive area or in dead zones
433 // Arguments: x,y -position
434 // Returns: 1 if not in sensitive zone
435              
436   for(Int_t iPc=0;iPc<6;iPc++)
437     if(x>=fgkMinPcX[iPc] && x<=fgkMaxPcX[iPc] && y>=fgkMinPcY[iPc] && y<=fgkMaxPcY [iPc]) return kFALSE; //in current pc
438   
439   return kTRUE;
440 }
441 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
442 Double_t AliHMPIDPIDResponse::Sigma2(Double_t trkTheta,Double_t trkPhi,Double_t ckovTh, Double_t ckovPh) const {
443   
444 // Analithical calculation of total error (as a sum of localization, geometrical and chromatic errors) on Cerenkov angle for a given Cerenkov photon 
445 // created by a given MIP. Formules according to CERN-EP-2000-058 
446 // Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians]
447 //            dip and azimuthal angles for MIP taken at the entrance to radiator, [radians]        
448 //            MIP beta
449 // Returns: absolute error on Cerenkov angle, [radians]    
450   
451   TVector3 v(-999,-999,-999);
452   Double_t trkBeta = 1./(TMath::Cos(ckovTh)*GetRefIdx());
453   
454   if(trkBeta > 1) trkBeta = 1;                 //protection against bad measured thetaCer  
455   if(trkBeta < 0) trkBeta = 0.0001;            //
456
457   v.SetX(SigLoc (trkTheta,trkPhi,ckovTh,ckovPh,trkBeta));
458   v.SetY(SigGeom(trkTheta,trkPhi,ckovTh,ckovPh,trkBeta));
459   v.SetZ(SigCrom(trkTheta,ckovTh,ckovPh,trkBeta));
460
461   return v.Mag2();
462 }
463 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
464 Double_t AliHMPIDPIDResponse::SigLoc(Double_t trkTheta,Double_t trkPhi,Double_t thetaC, Double_t phiC,Double_t betaM) const {
465   
466 // Analitical calculation of localization error (due to finite segmentation of PC) on Cerenkov angle for a given Cerenkov photon 
467 // created by a given MIP. Fromulae according to CERN-EP-2000-058 
468 // Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians]
469 //            dip and azimuthal angles for MIP taken at the entrance to radiator, [radians]        
470 //            MIP beta
471 // Returns: absolute error on Cerenkov angle, [radians]    
472   
473   Double_t phiDelta = phiC;
474
475   Double_t sint     = TMath::Sin(trkTheta);
476   Double_t cost     = TMath::Cos(trkTheta);
477   Double_t sinf     = TMath::Sin(trkPhi);
478   Double_t cosf     = TMath::Cos(trkPhi);
479   Double_t sinfd    = TMath::Sin(phiDelta);
480   Double_t cosfd    = TMath::Cos(phiDelta);
481   Double_t tantheta = TMath::Tan(thetaC);
482   
483   Double_t alpha =cost-tantheta*cosfd*sint;                                                    // formula (11)
484   Double_t k = 1.-GetRefIdx()*GetRefIdx()+alpha*alpha/(betaM*betaM);                           // formula (after 8 in the text)
485   if (k<0) return 1e10;
486   Double_t mu =sint*sinf+tantheta*(cost*cosfd*sinf+sinfd*cosf);                                // formula (10)
487   Double_t e  =sint*cosf+tantheta*(cost*cosfd*cosf-sinfd*sinf);                                // formula (9)
488
489   Double_t kk = betaM*TMath::Sqrt(k)/(GapThick()*alpha);                                       // formula (6) and (7)
490   Double_t dtdxc = kk*(k*(cosfd*cosf-cost*sinfd*sinf)-(alpha*mu/(betaM*betaM))*sint*sinfd);    // formula (6)           
491   Double_t dtdyc = kk*(k*(cosfd*sinf+cost*sinfd*cosf)+(alpha* e/(betaM*betaM))*sint*sinfd);    // formula (7)            pag.4
492   
493   Double_t errX = 0.2,errY=0.25;                                                                //end of page 7
494   return  TMath::Sqrt(errX*errX*dtdxc*dtdxc + errY*errY*dtdyc*dtdyc); 
495 }
496 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
497 Double_t AliHMPIDPIDResponse::SigCrom(Double_t trkTheta,Double_t thetaC, Double_t phiC,Double_t betaM) const {
498
499 // Analitical calculation of chromatic error (due to lack of knowledge of Cerenkov photon energy) on Cerenkov angle for a given Cerenkov photon 
500 // created by a given MIP. Fromulae according to CERN-EP-2000-058 
501 // Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians]
502 //            dip and azimuthal angles for MIP taken at the entrance to radiator, [radians]        
503 //            MIP beta
504 //   Returns: absolute error on Cerenkov angle, [radians]    
505   
506   Double_t phiDelta = phiC;
507
508   Double_t sint     = TMath::Sin(trkTheta);
509   Double_t cost     = TMath::Cos(trkTheta);
510   Double_t cosfd    = TMath::Cos(phiDelta);
511   Double_t tantheta = TMath::Tan(thetaC);
512   
513   Double_t alpha =cost-tantheta*cosfd*sint;                                         // formula (11)
514   Double_t dtdn = cost*GetRefIdx()*betaM*betaM/(alpha*tantheta);                    // formula (12)
515             
516   Double_t f = 0.0172*(7.75-5.635)/TMath::Sqrt(24.);
517
518   return f*dtdn;
519 }//SigCrom()
520 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
521 Double_t AliHMPIDPIDResponse::SigGeom(Double_t trkTheta,Double_t trkPhi,Double_t thetaC, Double_t phiC,Double_t betaM) const {
522   
523 // Analitical calculation of geometric error (due to lack of knowledge of creation point in radiator) on Cerenkov angle for a given Cerenkov photon 
524 // created by a given MIP. Formulae according to CERN-EP-2000-058 
525 // Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians]
526 //            dip and azimuthal angles for MIP taken at the entrance to radiator, [radians]        
527 //            MIP beta
528 //   Returns: absolute error on Cerenkov angle, [radians]    
529
530   Double_t phiDelta = phiC;
531
532   Double_t sint     = TMath::Sin(trkTheta);
533   Double_t cost     = TMath::Cos(trkTheta);
534   Double_t sinf     = TMath::Sin(trkPhi);
535   Double_t cosfd    = TMath::Cos(phiDelta);
536   Double_t costheta = TMath::Cos(thetaC);
537   Double_t tantheta = TMath::Tan(thetaC);
538   
539   Double_t alpha =cost-tantheta*cosfd*sint;                                                // formula (11)
540   
541   Double_t k = 1.-GetRefIdx()*GetRefIdx()+alpha*alpha/(betaM*betaM);                       // formula (after 8 in the text)
542   if (k<0) return 1e10;
543
544   Double_t eTr = 0.5*RadThick()*betaM*TMath::Sqrt(k)/(GapThick()*alpha);                    // formula (14)
545   Double_t lambda = (1.-sint*sinf)*(1.+sint*sinf);                                          // formula (15)
546
547   Double_t c1 = 1./(1.+ eTr*k/(alpha*alpha*costheta*costheta));                             // formula (13.a)
548   Double_t c2 = betaM*TMath::Power(k,1.5)*tantheta*lambda/(GapThick()*alpha*alpha);         // formula (13.b)
549   Double_t c3 = (1.+eTr*k*betaM*betaM)/((1+eTr)*alpha*alpha);                               // formula (13.c)
550   Double_t c4 = TMath::Sqrt(k)*tantheta*(1-lambda)/(GapThick()*betaM);                      // formula (13.d)
551   Double_t dtdT = c1 * (c2+c3*c4);
552   Double_t trErr = RadThick()/(TMath::Sqrt(12.)*cost);
553
554   return trErr*dtdT;
555 }//SigGeom()
556 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
557 Double_t AliHMPIDPIDResponse::GetNMean(const AliVTrack *vTrk) const {
558
559   // 
560   // mean refractive index calculation
561   //
562   Double_t nmean = -999.; 
563   
564   Float_t xPc=0.,yPc=0.,thRa=0.,phRa=0.;
565   vTrk->GetHMPIDtrk(xPc,yPc,thRa,phRa);
566   
567   const Int_t ch = vTrk->GetHMPIDcluIdx()/1000000;
568   
569   const Double_t yRa = yPc - (RadThick()+WinThick()+GapThick())*TMath::Sin(phRa)*TMath::Tan(thRa);  //just linear extrapolation back to RAD
570       
571   TF1 *RefIndex=0x0;
572   
573   if(GetRefIndexArray()) RefIndex = (TF1*)(GetRefIndexArray()->At(ch));
574   else return nmean;
575   
576   if(RefIndex) nmean = RefIndex->Eval(yRa);
577   else return nmean;
578   
579   return nmean;   
580 }  
581 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
582 Double_t AliHMPIDPIDResponse::SigmaCorrFact  (Int_t iPart, Double_t occupancy) {
583
584 // calculation of sigma correction factor
585   
586   Double_t corr = 1.0;
587        
588   switch(iPart) {
589     case 0: corr = 0.115*occupancy + 1.166; break; 
590     case 1: corr = 0.115*occupancy + 1.166; break;
591     case 2: corr = 0.115*occupancy + 1.166; break;
592     case 3: corr = 0.065*occupancy + 1.137; break;
593     case 4: corr = 0.048*occupancy + 1.202; break;
594   }                                                                                                                           
595  return corr; 
596 }
597