/************************************************************************** * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. * * * * Author: The ALICE Off-line Project. * * Contributors are mentioned in the code where appropriate. * * * * Permission to use, copy, modify and distribute this software and its * * documentation strictly for non-commercial purposes is hereby granted * * without fee, provided that the above copyright notice appears in all * * copies and that both the copyright notice and this permission notice * * appear in the supporting documentation. The authors make no claims * * about the suitability of this software for any purpose. It is * * provided "as is" without express or implied warranty. * **************************************************************************/ /* $Id$ */ #include #include #include "AliITSsegmentationSSD.h" ////////////////////////////////////////////////////// // Segmentation class for // // silicon strips // // // ////////////////////////////////////////////////////// const Float_t AliITSsegmentationSSD::fgkDxDefault = 72960.; const Float_t AliITSsegmentationSSD::fgkDzDefault = 40000.; const Float_t AliITSsegmentationSSD::fgkDyDefault = 300.; const Float_t AliITSsegmentationSSD::fgkPitchDefault = 95.; const Int_t AliITSsegmentationSSD::fgkNstripsDefault = 768; ClassImp(AliITSsegmentationSSD) AliITSsegmentationSSD::AliITSsegmentationSSD(): AliITSsegmentation(), fNstrips(0), fStereoP(0), fStereoN(0), fPitch(0), fStereoPl5(0), fStereoNl5(0), fStereoPl6(0), fStereoNl6(0), fLayer(0){ // default constructor } //---------------------------------------------------------------------- AliITSsegmentationSSD::AliITSsegmentationSSD(AliITSgeom *geom): fNstrips(0), fStereoP(0), fStereoN(0), fPitch(0), fStereoPl5(0), fStereoNl5(0), fStereoPl6(0), fStereoNl6(0), fLayer(0){ // constuctor fGeom = geom; fCorr = 0; SetDetSize(fgkDxDefault,fgkDzDefault,fgkDyDefault); SetPadSize(fgkPitchDefault,0.); SetNPads(fgkNstripsDefault,0); SetAngles(); fLayer = 0; } //______________________________________________________________________ void AliITSsegmentationSSD::Copy(TObject &obj) const { // protected method. copy this to obj AliITSsegmentation::Copy(obj); ((AliITSsegmentationSSD& ) obj).Clear(); ((AliITSsegmentationSSD& ) obj).fNstrips = fNstrips; ((AliITSsegmentationSSD& ) obj).fStereoP = fStereoP; ((AliITSsegmentationSSD& ) obj).fStereoN = fStereoN; ((AliITSsegmentationSSD& ) obj).fStereoPl5 = fStereoPl5; ((AliITSsegmentationSSD& ) obj).fStereoNl5 = fStereoNl5; ((AliITSsegmentationSSD& ) obj).fStereoPl6 = fStereoPl6; ((AliITSsegmentationSSD& ) obj).fStereoNl6 = fStereoNl6; ((AliITSsegmentationSSD& ) obj).fLayer = fLayer; ((AliITSsegmentationSSD& ) obj).fPitch = fPitch; ((AliITSsegmentationSSD& ) obj).fLayer = fLayer; } //______________________________________________________________________ AliITSsegmentationSSD& AliITSsegmentationSSD::operator=( const AliITSsegmentationSSD &source){ // Operator = if(this != &source){ source.Copy(*this); } return *this; } //______________________________________________________________________ AliITSsegmentationSSD::AliITSsegmentationSSD(const AliITSsegmentationSSD &source): AliITSsegmentation(source), fNstrips(0), fStereoP(0), fStereoN(0), fPitch(0), fStereoPl5(0), fStereoNl5(0), fStereoPl6(0), fStereoNl6(0), fLayer(0){ // copy constructor source.Copy(*this); } //---------------------------------------------------------------------- void AliITSsegmentationSSD::Init(){ // standard initalizer SetPadSize(fgkPitchDefault,0.); SetNPads(fgkNstripsDefault,0); SetAngles(); } //---------------------------------------------------------------------- void AliITSsegmentationSSD::Angles(Float_t &aP,Float_t &aN) const{ // P and N side stereo angles if (fLayer == 5){ aP = fStereoPl5; aN = fStereoNl5; } // end if if (fLayer == 6){ aP = fStereoPl6; aN = fStereoNl6; } // end if } //---------------------------------------------------------------------- void AliITSsegmentationSSD::SetLayer(Int_t l){ //set fLayer data member (only 5 or 6 are allowed) if (l==5) fLayer =5; if (l==6) fLayer =6; if((l!=5) && (l!=6))Error("SetLayer","Layer can be 5 or 6, not %d",l); } //---------------------------------------------------------------------- void AliITSsegmentationSSD::GetPadTxz(Float_t &x,Float_t &z) const{ // returns P and N sided strip numbers for a given location. // Transformation from microns detector center local coordinates // to detector P and N side strip numbers.. /* _- Z + angle / ^ fNstrips v | N-Side ...0 \-------/------------|-----------\--------\ |\\\\\\/////////////.|\\\\\\\\\\\\\\\\\\\\| |0\\\\/////////////..|.\\\\\\\\\\\\\\\\\\\| |00\\/////////////...|..\\\\\\\\\\\\\\\\\\| X <--|000/////////////... |...\\\\\\\\\\\\\\\\\| |00/////////////... | ...\\\\\\\\\\\\\\\\| |0/////////////... | ...\\\\\\\\\\\\\\\| |//////////////... | ...\\\\\\\\\\\\\\\| /-----\--------------|--------------------/ fNstrips-1 P-Side ...0 |0\ |00\ Dead region: |000/ |00/ |0/ // expects x, z in microns */ Float_t stereoP, stereoN; Angles(stereoP,stereoN); Float_t tanP = TMath::Tan(stereoP); Float_t tanN = TMath::Tan(-stereoN); Float_t x1 = x; Float_t z1 = z; x1 += fDx/2; z1 += fDz/2; x = (x1 - z1*tanP)/fPitch; z = (x1 - tanN*(z1 - fDz))/fPitch; } //---------------------------------------------------------------------- void AliITSsegmentationSSD::GetPadIxz(Float_t x,Float_t z,Int_t &iP,Int_t &iN) const { // returns P and N sided strip numbers for a given location. /* _- Z + angle / ^ fNstrips v | N-Side ...0 \-------/------------|-----------\--------\ |\\\\\\/////////////.|\\\\\\\\\\\\\\\\\\\\| |0\\\\/////////////..|.\\\\\\\\\\\\\\\\\\\| |00\\/////////////...|..\\\\\\\\\\\\\\\\\\| X <--|000/////////////... |...\\\\\\\\\\\\\\\\\| |00/////////////... | ...\\\\\\\\\\\\\\\\| |0/////////////... | ...\\\\\\\\\\\\\\\| |//////////////... | ...\\\\\\\\\\\\\\\| /-----\--------------|--------------------/ fNstrips-1 P-Side ...0 |0\ |00\ Dead region: |000/ |00/ |0/ // expects x, z in microns */ Float_t stereoP, stereoN; Angles(stereoP,stereoN); Float_t tanP=TMath::Tan(stereoP); Float_t tanN=TMath::Tan(stereoN); Float_t x1=x,z1=z; x1 += fDx/2; z1 += fDz/2; Float_t ldX = x1 - z1*tanP; // distance from left-down edge iP = (Int_t)(ldX/fPitch); iP = (iP<0)? -1: iP; iP = (iP>fNstrips)? -1: iP; ldX = x1 - tanN*(fDz - z1); iN = (Int_t)(ldX/fPitch); iN = (iN<0)? -1: iN; iN = (iN>fNstrips)? -1: iN; } //------------------------------------------------------- void AliITSsegmentationSSD::GetPadCxz(Int_t iP,Int_t iN,Float_t &x,Float_t &z) const { // actually this is the GetCrossing(Float_t &,Float_t &) // returns local x, z in microns ! Float_t lDx = fDx; // detector size in x direction, microns Float_t lDz = fDz; // detector size in z direction, microns Float_t xP; // x coordinate in the P side from the first P strip Float_t xN; // x coordinate in the N side from the first N strip Float_t stereoP, stereoN; Angles(stereoP,stereoN); Float_t kP=TMath::Tan(stereoP); Float_t kN=TMath::Tan(stereoN); xP=iP*fPitch; xN=iN*fPitch; x = xP + kP*(lDz*kN-xP+xN)/(kP+kN); z = (lDz*kN-xP+xN)/(kP+kN); x -= lDx/2; z -= lDz/2; //if(TMath::Abs(z) > Dz/2) cout<<"Warning, wrong z local ="<GetPadTxz(x,z); // first for P side iP = (Int_t) x; if(iP<0 || iP>=fNstrips) iP=-1; // strip number must be in range. // Now for N side) iN = (Int_t) z; if(iN<0 || iN>=fNstrips) iN=-1; // strip number must be in range. return kTRUE; } //---------------------------------------------------------------------- void AliITSsegmentationSSD::DetToLocal(Int_t ix,Int_t iPN, Float_t &x,Float_t &z) const{ // Transformation from detector segmentation/cell coordiantes starting // from 0. iPN=0 for P side and 1 for N side strip. Returned is z=0.0 // and the corresponding x value.. /* _- Z + angle / ^ fNstrips v | N-Side ...0 \-------/------------|-----------\--------\ |\\\\\\/////////////.|\\\\\\\\\\\\\\\\\\\\| |0\\\\/////////////..|.\\\\\\\\\\\\\\\\\\\| |00\\/////////////...|..\\\\\\\\\\\\\\\\\\| X <--|000/////////////... |...\\\\\\\\\\\\\\\\\| |00/////////////... | ...\\\\\\\\\\\\\\\\| |0/////////////... | ...\\\\\\\\\\\\\\\| |//////////////... | ...\\\\\\\\\\\\\\\| /-----\--------------|--------------------/ fNstrips-1 P-Side ...0 |0\ |00\ Dead region: |000/ |00/ |0/ */ // for strips p-side // x = a + b + z*tan(fStereoP); a = Dpx(iP)*(iP+0.5)-dx; b = dz*th; // for strips n-side // x = a + b + z*tan(fStereoP); a = Dpx(iN)*(iN+0.5)-dx; b = -dz*th; const Double_t kconst = 1.0E-04; // convert microns to cm. Float_t flag=kconst*Dx(); // error value Double_t th=0.0,dx,dz,i,a,b=0.0,xb[4],zb[4]; Float_t stereoP, stereoN; Angles(stereoP,stereoN); z = 0.0; // Strip center in z. if(iPN<0 || iPN>1){// if error return full detector size in x. x = z = flag; return; } // end if if(ix<0 || ix>=fNstrips) { // if error return full detector size in x. x = z = flag; return; } // end if i = (Double_t) ix; // convert to double dx = 0.5*kconst*Dx(); // half distance in x in cm dz = 0.5*kconst*Dz(); // half distance in z in cm a = kconst*Dpx(ix)*(i+0.5)-dx; // Min x value. if(iPN==0){ //P-side angle defined backwards. th = TMath::Tan(stereoP); b = dz*th; }else if(iPN==1){ // N-side th = TMath::Tan(-stereoN); b = -dz*th; } // end if // compute average/center position of the strip. xb[0] = +dx; if(th!=0.0) zb[0] = (+dx-a-b)/th; else zb[0] = 0.0; xb[1] = -dx; if(th!=0.0) zb[1] = (-dx-a-b)/th; else zb[1] = 0.0; xb[2] = a+b+dz*th; zb[2] = +dz; xb[3] = a+b-dz*th; zb[3] = -dz; x = 0.0; z = 0.0; for(Int_t j=0;j<4;j++){ if(xb[j]>=-dx && xb[j]<=dx && zb[j]>=-dz && zb[j]<=dz){ x += xb[j]; z += zb[j]; } // end if } // end for x *= 0.5; z *= 0.5; return; } //---------------------------------------------------------------------- Bool_t AliITSsegmentationSSD::GetCrossing(Int_t iP,Int_t iN, Float_t &x,Float_t &z, Float_t c[2][2]){ // Given one P side strip and one N side strip, Returns kTRUE if they // cross each other and the location of the two crossing strips and // their correxlation matrix c[2][2]. /* _- Z + angle / ^ fNstrips v | N-Side ...0 \-------/------------|-----------\--------\ |\\\\\\/////////////.|\\\\\\\\\\\\\\\\\\\\| |0\\\\/////////////..|.\\\\\\\\\\\\\\\\\\\| |00\\/////////////...|..\\\\\\\\\\\\\\\\\\| X <--|000/////////////... |...\\\\\\\\\\\\\\\\\| |00/////////////... | ...\\\\\\\\\\\\\\\\| |0/////////////... | ...\\\\\\\\\\\\\\\| |//////////////... | ...\\\\\\\\\\\\\\\| /-----\--------------|--------------------/ fNstrips-1 P-Side ...0 |0\ |00\ Dead region: |000/ |00/ |0/ c[2][2] is defined as follows /c[0][0] c[0][1]\ /delta iP\ = /delta x\ \c[1][0] c[1][1]/ \delta iN/ = \delta z/ */ const Double_t kconst = 1.0E-04; // convert microns to cm. Double_t thp,thn,th,dx,dz,p,ip,in; Float_t stereoP, stereoN; Angles(stereoP,stereoN); thp = TMath::Tan(stereoP); thn = TMath::Tan(-stereoN); th = thp-thn; if(th==0.0) { // parall strips then never cross. x = 0.0; z = 0.0; c[0][0] = c[1][0] = c[0][1] = c[1][1] = 0.0; return kFALSE; } // end if // The strips must cross some place in space. ip = (Double_t) iP; // convert to double now for speed in = (Double_t) iN; // convert to double now for speed dx = 0.5*kconst*Dx(); // half distance in x in cm dz = 0.5*kconst*Dz(); // half distance in z in cm p = kconst*Dpx(iP); // Get strip spacing/pitch now x = 0.5*p+dx + (p*(in*thp-ip*thn)-2.0*dz*thp*thn)/th; z =(p*(in-ip)-dz*(thp+thn))/th; // compute correlations. c[0][0] = -thn*p/th; // dx/diP c[1][1] = p/th; // dz/diN c[0][1] = p*thp/th; // dx/diN c[1][0] = -p/th; // dz/diP if(x<-dx || x>dx || z<-dz || z>dz) return kFALSE; // crossing is outside // of the detector so // these strips don't // cross. return kTRUE; } //---------------------------------------------------------------------- void AliITSsegmentationSSD::PrintDefaultParameters() const { // Print default values for parameters. // Values specified as static const data members are shown cout<<"fgkDxDefault = "<