class AliRICHHelix: public TObject
{
public:
- AliRICHHelix() {;}
- AliRICHHelix(TVector3 x0,TVector3 p0,Int_t q,Double_t b=0.4) {fX0=x0;fP0=p0;fQ=q;fBz=b;} //takes position and momentum at parametrised point
- virtual ~AliRICHHelix() {;}
- inline void Propagate(Double_t lenght);
- Bool_t Intersection(TVector3 plane) {return Intersection(plane,plane.Unit());} // special plane given by point only
- inline Bool_t Intersection(TVector3 planePoint,TVector3 planeNorm); //intersection with plane given by point and normal vector
- inline Int_t RichIntersect(AliRICHParam *pParam);
- TVector3 X()const {return fX;}
- TVector3 P()const {return fP;}
- TVector3 X0()const {return fX0;}
- TVector3 P0()const {return fP0;}
- TVector2 PosPc() const {return fPosPc;} //returns position of intersection with PC
- TVector2 PosRad()const {return fPosRad;} //returns position of intersection with radiator
- TVector3 Ploc()const {return fPloc;} //returns momentum at the position of intersection with radiator
-
- void Print(Option_t *sOption)const; //virtual interface from TObject
+ AliRICHHelix():TObject() {;}
+ AliRICHHelix(const TVector3 &x0,const TVector3 &p0,Int_t q=1,Double_t b=0.2):TObject(),fX0(x0),fP0(p0),fX(x0),fP(p0),
+ fLen(0),fQ(q),fBz(b) {;}
+ virtual ~AliRICHHelix() {;}
+
+ inline void Propagate(Double_t len); //propogate helix by length len along it
+ inline Int_t RichIntersect(AliRICHParam *pParam); //search intersection with any RICH chamber
+ inline Bool_t Intersection(TVector3 planePnt,TVector3 planeNorm); //intersection with plane given by point and normal vector
+ Bool_t Intersection(TVector3 pl) {return Intersection(pl,pl.Unit());} // special plane given by point only
+ TVector2 PosRad() const{return fPosRad;} //returns position of intersection with radiator (local system)
+ TVector2 PosAnod() const{return fPosAnod;} //returns position of intersection with anod wires plane (local system)
+ TVector2 PosPc() const{return fPosPc;} //returns position of intersection with PC (local system)
+ TVector3 Ploc() const{return fPloc;} //returns momentum at the position of intersection with radiator
+ Double_t Length() const{return fLen;} //returns length of the track from initial point to RICH
+ void Print(Option_t *sOption)const; //virtual interface from TObject
protected:
TVector3 fX0; //helix position in parametrised point, cm in MRS
TVector3 fP0; //helix momentum in parametrised point, GeV/c in MRS
TVector3 fX; //helix position in point of interest, cm in MRS
TVector3 fP; //helix momentum in point of interest, GeV/c in MRS
- Double_t fLength; //helix length in point of interest
+ Double_t fLen; //helix length in point of interest
Int_t fQ; //sign of track charge (value not provided by current ESD)
Double_t fBz; //magnetic field along z value in Tesla under assumption of uniformity
- TVector2 fPosPc; //position on PC in local system
- TVector2 fPosRad; //position on radiator in local system
+ TVector2 fPosRad; //track intersection with radiator (local system)
+ TVector2 fPosAnod; //track intersection with anod wires plane (local system)
+ TVector2 fPosPc; //track intersection with PC (local system)
TVector3 fPloc; //momentum in local system
ClassDef(AliRICHHelix,0) //General helix
};//class AliRICHHelix
//__________________________________________________________________________________________________
-void AliRICHHelix::Propagate(Double_t length)
+void AliRICHHelix::Propagate(Double_t len)
{
// Propogates the helix to the position of interest defined by helix length s
// Assumes uniform magnetic field along z direction.
Double_t a = -c*fBz*fQ;
Double_t rho = a/fP0.Mag();
- fX.SetX( fX0.X()+fP0.X()*TMath::Sin(rho*length)/a-fP0.Y()*(1-TMath::Cos(rho*length))/a );
- fX.SetY( fX0.Y()+fP0.Y()*TMath::Sin(rho*length)/a+fP0.X()*(1-TMath::Cos(rho*length))/a );
- fX.SetZ( fX0.Z()+fP0.Z()*length/fP0.Mag() );
- fP.SetX( fP0.X()*TMath::Cos(rho*length)-fP0.Y()*TMath::Sin(rho*length) );
- fP.SetY( fP0.Y()*TMath::Cos(rho*length)+fP0.X()*TMath::Sin(rho*length) );
- fP.SetZ( fP0.Z() );
- fLength=length;
+ fX.SetX( fX0.X()+fP0.X()*TMath::Sin(rho*len)/a-fP0.Y()*(1-TMath::Cos(rho*len))/a );
+ fX.SetY( fX0.Y()+fP0.Y()*TMath::Sin(rho*len)/a+fP0.X()*(1-TMath::Cos(rho*len))/a );
+ fX.SetZ( fX0.Z()+fP0.Z()*len/fP0.Mag() );
+ fP.SetX( fP0.X()*TMath::Cos(rho*len)-fP0.Y()*TMath::Sin(rho*len) );
+ fP.SetY( fP0.Y()*TMath::Cos(rho*len)+fP0.X()*TMath::Sin(rho*len) );
+ fP.SetZ( fP0.Z() );
+ fLen=len;
}
//__________________________________________________________________________________________________
Bool_t AliRICHHelix::Intersection(TVector3 planePoint,TVector3 planeNorm)
// Returns kTrue if helix intersects the plane, kFALSE otherwise.
// Stores result in current helix fields fX and fP.
- Double_t s=(planePoint-fX0)*planeNorm,dist=99999,distPrev=dist;
+ Double_t s=(planePoint-fX0)*planeNorm,dist=99999,distPrev=dist;//estimates initial distance to plane
- while(TMath::Abs(dist)>0.0001){
+ while(TMath::Abs(dist)>0.00001){
Propagate(s); //calculates helix at the distance s from x0 ALONG the helix
dist=(fX-planePoint)*planeNorm; //distance between current helix position and plane
if(TMath::Abs(dist) >= TMath::Abs(distPrev)) { return kFALSE;}
if(Intersection(pParam->C(iChamberN)->Rad())){//there is intersection with radiator plane
fPosRad=pParam->C(iChamberN)->Mrs2Rad(fX);//position on radiator plane
if(pParam->IsAccepted(fPosRad)){//intersection within radiator (even if in dead zone)
+
if(Intersection(pParam->C(iChamberN)->Pc())){//there is intersection with photocathode
fPosPc=pParam->C(iChamberN)->Mrs2Pc(fX);//position on photcathode plane
if(pParam->IsAccepted(fPosPc)){//intersection within pc (even if in dead zone)
- fPloc=pParam->C(iChamberN)->PMrs2Loc(fP);
+
+ Intersection(pParam->C(iChamberN)->Anod()); //search for anod intersection position
+ fPosAnod=pParam->C(iChamberN)->Mrs2Anod(fX);
+
+ fPloc=pParam->C(iChamberN)->PMrs2Loc(fP);//trasform p to local system
return iChamberN;
}//if inside PC
- }//if for PC
+ }//if intersects PC
+
}//if inside radiator
}//if for radiator
}//chamber loop
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff