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[u/mrichter/AliRoot.git] / TPC / AliTPCv2.cxx

/**************************************************************************
 * 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.                  *
 **************************************************************************/

/*
$Log$
*/

///////////////////////////////////////////////////////////////////////////////
//                                                                           //
//  Time Projection Chamber version 2 -- detailed TPC and slow simulation    //
//                                                                           //
//Begin_Html
/*
<img src="picts/AliTPCv2Class.gif">
*/
//End_Html
//                                                                           //
//                                                                           //
///////////////////////////////////////////////////////////////////////////////
#include <stdlib.h>

#include <TMath.h>

#include "AliTPCv2.h"
#include "AliTPCD.h"
#include "AliRun.h"
#include "AliConst.h"

ClassImp(AliTPCv2)
 
//_____________________________________________________________________________
AliTPCv2::AliTPCv2(const char *name, const char *title) :
  AliTPC(name, title) 
{
  //
  // Standard constructor for Time Projection Chamber version 2
  //
  fIdSens1=0;
  fIdSens2=0;
  SetBufferSize(128000);
}
 
//_____________________________________________________________________________
void AliTPCv2::CreateGeometry()
{
  //
  // Create the geometry of Time Projection Chamber version 2
  //
  //Begin_Html
  /*
    <img src="picts/AliTPCv2.gif">
  */
  //End_Html
  //Begin_Html
  /*
    <img src="picts/AliTPCv2Tree.gif">
  */
  //End_Html

  AliTPCParam * fTPCParam = &(fDigParam->GetParam());

  Int_t *idtmed = fIdtmed->GetArray();

  Float_t dm[21];
  Int_t idrotm[120];

  Int_t nRotMat = 0;

  Int_t i,ifl1,ifl2;

  Int_t nInnerSector = fTPCParam->GetNInnerSector()/2;
  Int_t nOuterSector = fTPCParam->GetNOuterSector()/2;
  
  // --------------------------------------------------- 
  //        sector specification check 
  // --------------------------------------------------- 
  if (fSecAL >= 0) {
    ifl1 = 0;
    
    for (i = 0; i < 6; ++i) {
      if (fSecLows[i] >= 0 && fSecLows[i] < 2*nInnerSector) {
	ifl1 = 1;
	printf("*** SECTOR %d selected\n",fSecLows[i]);
      }
    }

  } else {
    printf("*** ALL LOWER SECTORS SELECTED ***\n");
    ifl1 = 1;
  }

  if (fSecAU >= 0) {
    ifl2 = 0;
    
    for (i = 0; i < 12; ++i) {
      if (fSecUps[i] > 2*nInnerSector-1 && 
          fSecUps[i] < 2*(nInnerSector+nOuterSector)) {
	ifl2 = 1;
	printf("*** SECTOR %d selected\n",fSecUps[i]);
      }
    }
    
  } else {
    printf("*** ALL UPPER SECTORS SELECTED ***\n");
    ifl1 = 1;
  }
  
  if (ifl1 == 0 && ifl2 == 0) {
    printf("*** ERROR: AT LEAST ONE SECTOR MUST BE SPECIFIED ***\n");
    printf("!!! PROGRAM STOPPED !!!\n");
    exit(1);
  }
  
  if ((fSecAL < 0 || fSecAU < 0) && fSens >= 0) {
    printf("** ERROR: STRIPS CANNOT BE SPECIFIED FOR ALL SECTORS **\n");
    printf("!!! PROGRAM STOPPED !!!\n");
    exit(1);
  }
  
  // ---------------------------------------------------- 
  //          FIELD CAGE WITH ENDCAPS - G10
  //          THIS IS ALSO A TPC MOTHER VOLUME 
  // ---------------------------------------------------- 

  dm[0] = 76.;
  dm[1] = 278.;
  dm[2] = 275.;

  gMC->Gsvolu("TPC ", "TUBE", idtmed[8], dm, 3); 

  //-----------------------------------------------------
  //  Endcap cover c-fibre 0.86% X0
  //-----------------------------------------------------

  dm[0] = 78.;
  dm[1] = 258.;
  dm[2] = 0.95;

  gMC->Gsvolu("TPEC","TUBE",idtmed[10],dm,3);

  //-----------------------------------------------------
  // Drift gas , leave 2 cm at the outer radius
  // and inner raddius
  //-----------------------------------------------------

  dm[0] = 78.;
  dm[1] = 258.;
  dm[2] = 250.;

  gMC->Gsvolu("TGAS", "TUBE", idtmed[3], dm, 3);

  //------------------------------------------------------
  //  membrane holder - carbon fiber
  //------------------------------------------------------


  gMC->Gsvolu("TPMH","TUBE",idtmed[6],dm,0);

  dm[0] = 252.;
  dm[1] = 258.;
  dm[2] = 0.2;

  gMC->Gsposp("TPMH",1,"TGAS",0.,0.,0.,0,"ONLY",dm,3);
 
  dm[0] = 78.;
  dm[2] = 82.;
  dm[2] = 0.1;

  gMC->Gsposp("TPMH",2,"TGAS",0.,0.,0.,0,"ONLY",dm,3);

  //----------------------------------------------------------
  //  HV membrane - 25 microns of mylar
  //----------------------------------------------------------

  dm[0] = 82.;
  dm[1] = 252.;
  dm[2] = 0.00125;

  gMC->Gsvolu("TPHV","TUBE",idtmed[5],dm,3);

  gMC->Gspos("TPHV",1,"TGAS",0.,0.,0.,0,"ONLY");

  gMC->Gspos("TGAS",1,"TPC ",0.,0.,0.,0,"ONLY");

  //----------------------------------------------------------
  // "side" gas volume, the same as the drift gas
  // the readout chambers are placed there.  
  //----------------------------------------------------------

  dm[0] = 78.;
  dm[1] = 258.;
  dm[2] = 0.5*(275. - 250.);
   
  gMC->Gsvolu("TPSG", "TUBE", idtmed[2], dm, 3);

  Float_t z_side = dm[2]; // 1/2 of the side gas thickness

  //-----------------------------------------------------------
  //   Readout chambers , 25% of X0, I use Al as the material
  //-----------------------------------------------------------

  Float_t InnerOpenAngle = fTPCParam->GetInnerAngle();
  Float_t OuterOpenAngle = fTPCParam->GetOuterAngle();

  Float_t InnerAngleShift = fTPCParam->GetInnerAngleShift();
  Float_t OuterAngleShift = fTPCParam->GetOuterAngleShift();

  Float_t InSecLowEdge = fTPCParam->GetInSecLowEdge();
  Float_t InSecUpEdge =  fTPCParam->GetInSecUpEdge();

  Float_t OuSecLowEdge = fTPCParam->GetOuSecLowEdge();
  Float_t OuSecUpEdge = fTPCParam->GetOuSecUpEdge();


  Float_t SecThick = 2.225; // Al

  Float_t edge = fTPCParam->GetEdge();

  //  S (Inner) sectors

  dm[0] = InSecLowEdge*TMath::Tan(0.5*InnerOpenAngle)-edge;
  dm[1] = InSecUpEdge*TMath::Tan(0.5*InnerOpenAngle)-edge;
  dm[2] = 0.5*SecThick;
  dm[3] = 0.5*(InSecUpEdge-InSecLowEdge);

  Float_t xCenterS = InSecLowEdge+dm[3];

  gMC->Gsvolu("TRCS", "TRD1", idtmed[0], dm, 4); 

  //  L (Outer) sectors

  dm[0] = OuSecLowEdge*TMath::Tan(0.5*OuterOpenAngle)-edge;
  dm[1] = OuSecUpEdge*TMath::Tan(0.5*OuterOpenAngle)-edge;
  dm[2] = 0.5*SecThick;
  dm[3] = 0.5*(OuSecUpEdge-OuSecLowEdge);

  Float_t xCenterL = OuSecLowEdge+dm[3];  

  gMC->Gsvolu("TRCL", "TRD1", idtmed[0], dm, 4);

  Float_t z1 = -z_side + SecThick*0.5;

  //------------------------------------------------------------------
  // S sectors - "gas sectors" (TRD1)
  //------------------------------------------------------------------

  dm[0] = InSecLowEdge*TMath::Tan(0.5*InnerOpenAngle)-0.01;
  dm[1] = InSecUpEdge*TMath::Tan(0.5*InnerOpenAngle)-0.01;
  dm[2] = 0.5*(250. - 0.001);
  dm[3] = 0.5*(InSecUpEdge-InSecLowEdge);  

  gMC->Gsvolu("TSGA", "TRD1", idtmed[4], dm, 4); // sensitive

  // ------------------------------------------------------------- 
  //  Only for the debugging purpose and resolution calculation 
  //  Sensitive strips at the pad-row center 
  // ------------------------------------------------------------- 

  Int_t ns;

  if(fSens>=0){

    Float_t r1,r2,zz;

    Float_t StripThick = 0.01; // 100 microns
    Float_t dead = fTPCParam->GetDeadZone();

    gMC->Gsvolu("TSST", "TRD1", idtmed[4], dm, 0);

    dm[2] = 0.5*(250. - 0.002);
    dm[3] = 0.5 * StripThick;


    for (ns = 0; ns < fTPCParam->GetNRowLow(); ns++) {

      r1 = fTPCParam->GetPadRowRadiiLow(ns);
      r2 = r1 + StripThick;     
      dm[0] = r1 * TMath::Tan(0.5*InnerOpenAngle) - dead;
      dm[1] = r2 * TMath::Tan(0.5*InnerOpenAngle) - dead;

      zz = -InSecLowEdge -0.5*(InSecUpEdge-InSecLowEdge);
      zz += r1;
      zz += dm[3];

      gMC->Gsposp("TSST", ns+1, "TSGA", 0., 0., zz, 0, "ONLY", dm, 4);

    
    }   

    gMC->Gsord("TSGA", 3); 
  
  } // if strips selected

  
  //-----------------------------------------------------------------
  //  L sectors - "gas sectors" (PGON to avoid overlaps)
  //-----------------------------------------------------------------

  dm[0] = 360.*kDegrad - 0.5*OuterOpenAngle;
  dm[0] *= kRaddeg;
  dm[0] = (Float_t)TMath::Nint(dm[0]);

  dm[1] = OuterOpenAngle*kRaddeg;
  dm[1] = (Float_t)TMath::Nint(dm[1]);

  dm[2] = 1.;
  dm[3] = 4.;

  dm[4] = 0.002;
  dm[5] = OuSecLowEdge;
  dm[6] = 252.*TMath::Cos(0.5*OuterOpenAngle)-0.002;

  dm[7] = dm[4]+0.2;
  dm[8] = dm[5];
  dm[9] = dm[6];

  dm[10] = dm[7];
  dm[11] = OuSecLowEdge;
  dm[12] = OuSecUpEdge;

  dm[13] = 250.;
  dm[14] = dm[11];
  dm[15] = dm[12];

  gMC->Gsvolu("TLGA","PGON",idtmed[4],dm,16);  

  if (fSens >= 0) {
    
    Float_t rmax = dm[6];
    Float_t r1,r2;
    Float_t dead = fTPCParam->GetDeadZone();

    Float_t StripThick = 0.01; // 100 microns

    gMC->Gsvolu("TLST", "PGON", idtmed[4], dm, 0);

    dm[0] = 360.*kDegrad - 0.5*OuterOpenAngle;
    dm[0] *= kRaddeg;
    dm[0] = (Float_t)TMath::Nint(dm[0]);

    dm[1] = OuterOpenAngle*kRaddeg;
    dm[1] = (Float_t)TMath::Nint(dm[1]);

    dm[2] = 1.;
    dm[3] = 2.;

    dm[7] = 250.;

    Float_t xx = dead/TMath::Tan(0.5*OuterOpenAngle);

    for(ns=0;ns<fTPCParam->GetNRowUp();ns++){

      r1 = fTPCParam->GetPadRowRadiiUp(ns)-xx;
      r2 = r1 + StripThick;

      dm[5] = r1;
      dm[6] = r2;

      dm[8] = r1;
      dm[9] = r2;

      if(r2+xx < rmax){
        dm[4] = 0.002;
      }
      else{
        dm[4] = 0.202;
      }

      gMC->Gsposp("TLST",ns+1,"TLGA",xx,0.,0.,0,"ONLY",dm,10);

    }    

        gMC->Gsord("TLGA", 4);

  } // if strips selected

  //------------------------------------------------------------------
  // Positioning of the S-sector readout chambers
  //------------------------------------------------------------------

  Float_t zs = 0.5*(250.+0.002);

  Float_t theta1,theta2,theta3;
  Float_t phi1,phi2,phi3;
  Float_t alpha;
  Float_t x,y;

  for(ns=0;ns<nInnerSector;ns++){
    
    phi1 = ns * InnerOpenAngle + 270.*kDegrad + InnerAngleShift;
    phi1 *= kRaddeg; // in degrees

    phi1 = (Float_t)TMath::Nint(phi1);

    if (phi1 > 360.) phi1 -= 360.;
      
    theta1 = 90.;
    phi2   = 90.;
    theta2 = 180.;
    phi3   = ns * InnerOpenAngle + InnerAngleShift;
    phi3 *= kRaddeg; // in degrees

    phi3 = (Float_t)TMath::Nint(phi3);
      
    if(phi3 > 360.) phi3 -= 360.;

    theta3 = 90.;

    alpha = phi3*kDegrad;

    x = xCenterS * TMath::Cos(alpha);
    y = xCenterS * TMath::Sin(alpha); 
 
    AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);  
     
    gMC->Gspos("TRCS", ns+1, "TPSG", x, y, z1, idrotm[nRotMat], "ONLY");

    if(fSecAL < 0){

      //---------------------------------------------------------------
      //  position all sectors
      //---------------------------------------------------------------

      gMC->Gspos("TSGA",ns+1,"TGAS",x,y,zs,idrotm[nRotMat], "ONLY");
      gMC->Gspos("TSGA",ns+1+nInnerSector,"TGAS",x,y,-zs,idrotm[nRotMat], "ONLY");
    }

    else{

      //---------------------------------------------------------------
      //  position selected sectors
      //---------------------------------------------------------------

      for(Int_t sel=0;sel<6;sel++){

        if(fSecLows[sel] == ns){
        gMC->Gspos("TSGA", ns+1, "TGAS", x, y, zs, idrotm[nRotMat], "ONLY");
	}
        else if(fSecLows[sel] == ns+nInnerSector){
        gMC->
          Gspos("TSGA",ns+1+nInnerSector,"TGAS", x, y,-zs,idrotm[nRotMat],"ONLY");
	}
      }
    }

    nRotMat++;     

  }
    
  //-------------------------------------------------------------------
  //  Positioning of the L-sectors readout chambers
  //-------------------------------------------------------------------
    
  for(ns=0;ns<nOuterSector;ns++){
    phi1 = ns * OuterOpenAngle + 270.*kDegrad + OuterAngleShift;
    phi1 *= kRaddeg; // in degrees

    phi1 = (Float_t)TMath::Nint(phi1);
    

    if (phi1 > 360.) phi1 -= 360.;
      
    theta1 = 90.;
    phi2   = 90.;
    theta2 = 180.;
    phi3   = ns * OuterOpenAngle+OuterAngleShift;
    phi3 *= kRaddeg; // in degrees

    phi3 = (Float_t)TMath::Nint(phi3);

      
    if(phi3 > 360.) phi3 -= 360.;

    theta3 = 90.;

    alpha = phi3*kDegrad;

    x = xCenterL * TMath::Cos(alpha);
    y = xCenterL * TMath::Sin(alpha); 
 
    AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);  
     

    gMC->Gspos("TRCL", ns+1, "TPSG", x, y, z1, idrotm[nRotMat], "ONLY"); 

    nRotMat++;   

  }

  //-------------------------------------------------------------------
  // Positioning of the L-sectors (gas sectors)
  //-------------------------------------------------------------------

  for(ns=0;ns<nOuterSector;ns++){

     phi1 = ns*OuterOpenAngle + OuterAngleShift;
     phi1 *= kRaddeg;
    
     phi1 = (Float_t)TMath::Nint(phi1);
     if(phi1>360.) phi1 -= 360.;

     theta1 = 90.;

     phi2 = 90. + phi1;
     if(phi2>360.) phi2 -= 360.;

     theta2 = 90.; 

     phi3 = 0.;
     theta3 = 0.;

     if(fSecAU < 0) {

       //--------------------------------------------------------------
       //  position all sectors
       //--------------------------------------------------------------

       AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3); 

       gMC->Gspos("TLGA",ns+1,"TGAS" ,0.,0.,0.,idrotm[nRotMat],"ONLY");

       nRotMat++;
   
       // reflection !!

       phi3 = 0.;
       theta3 = 180.;
     
       AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
  
       gMC->Gspos("TLGA",ns+1+nOuterSector,"TGAS" ,0.,0.,0.,idrotm[nRotMat],"ONLY");
          
       nRotMat++;
     }

     else{

       //---------------------------------------------------------------
       //  position selected sectors
       //---------------------------------------------------------------

       for(Int_t sel=0;sel<12;sel++){

         if(fSecUps[sel] == ns+2*nInnerSector){
           
          AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3); 
          gMC->Gspos("TLGA",ns+1,"TGAS" ,0.,0.,0.,idrotm[nRotMat],"ONLY");
          nRotMat++; 

	 }
         else if(fSecUps[sel] == ns+2*nInnerSector+nOuterSector){

	   // reflection

           phi3 = 0.;
           theta3 = 180.;

           AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
           gMC->
           Gspos("TLGA",ns+1+nOuterSector,"TGAS" ,0.,0.,0.,idrotm[nRotMat],"ONLY");
           nRotMat++; 

	 }

       }

     }

  }
  
  Float_t z0 = z_side - 0.95;

  gMC->Gspos("TPEC",1,"TPSG",0.,0.,z0,0,"ONLY");

  // ========================================================== 
  //                  wheels 
  // ========================================================== 

  //
  //  auxilary structures
  //


  gMC->Gsvolu("TPWI","TUBE",idtmed[24],dm,0); // "air" 

  // ---------------------------------------------------------- 
  //       Large wheel -> positioned in the TPC 
  // ---------------------------------------------------------- 
  

  z0 = 263.5; // TPC length - 1/2 spoke wheel width

  dm[0] = 258.;
  dm[1] = 278.;
  dm[2] = 11.5;
  
  gMC->Gsvolu("TPWL", "TUBE", idtmed[0], dm, 3); 

  dm[0] = dm[0]+2.;
  dm[1] = 278.;
  dm[2] = dm[2]-2.;

  gMC->Gsposp("TPWI",1,"TPWL",0.,0.,0.,0,"ONLY",dm,3);

  gMC->Gspos("TPWL", 1, "TPC ", 0, 0, z0, 0, "ONLY");
  gMC->Gspos("TPWL", 2, "TPC ", 0, 0, -z0, 0, "ONLY");

  //
  //  Outer vessel + CO2 HV degrader
  //

  dm[0] = 260.;
  dm[1] = 278.;
  dm[2] = 252.;

  gMC->Gsvolu("TPCO","TUBE",idtmed[12],dm,3);

  dm[0] = 275.;
  dm[1] = 278.;
  
  gMC->Gsvolu("TPOV","TUBE",idtmed[10],dm,3);

  gMC->Gspos("TPOV",1,"TPCO",0.,0.,0.,0,"ONLY");


  // G10 plugs

  dm[0] = 258.;
  dm[1] = 260.;
  dm[2] = 1.;

  gMC->Gsvolu("TPG1","TUBE",idtmed[8],dm,3);
  gMC->Gspos("TPG1",1,"TPCO",0.,0.,251.,0,"ONLY");
  gMC->Gspos("TPG1",2,"TPCO",0.,0.,-251.,0,"ONLY");  

  gMC->Gspos("TPCO",1,"TPC ",0.,0.,0.,0,"ONLY");


  //----------------------------------------------------------
  //  Small wheel -> positioned in "side gas
  //----------------------------------------------------------

  dm[0] = 78.;
  dm[1] = 82.;
  dm[2] = 11.5;

  gMC->Gsvolu("TPWS", "TUBE", idtmed[0], dm, 3);

  dm[0] = 78.;
  dm[1] = dm[1]-2;
  dm[2] = dm[2]-2.;

  gMC->Gsvolu("TPW1", "TUBE", idtmed[2], dm, 3);
  
  gMC->Gspos("TPW1", 1, "TPWS", 0., 0., 0., 0, "ONLY");

  z0 = 1.; // spoke wheel is shifted w.r.t. center of the "side gas"

  gMC->Gspos("TPWS", 1, "TPSG", 0, 0, z0, 0, "ONLY");


  // to avoid overlaps

  dm[0] = 76.;
  dm[1] = 78.;
  dm[2] = 11.5;

  gMC->Gsvolu("TPS1","TUBE",idtmed[0],dm,3);

  dm[2] = 9.5;

  gMC->Gsvolu("TPS2","TUBE",idtmed[24],dm,3);

  gMC->Gspos("TPS2",1,"TPS1",0.,0.,0.,0,"ONLY");

  z0= 263.5;
  
  gMC->Gspos("TPS1",1,"TPC ",0.,0.,z0,0,"ONLY");
  gMC->Gspos("TPS1",2,"TPC ",0.,0.,-z0,0,"ONLY");

  // G10 plug

  dm[0] = 76.;
  dm[1] = 78.;
  dm[2] = 1.;

  gMC->Gsvolu("TPG2","TUBE",idtmed[8],dm,3);

  z0 = 251.;

  gMC->Gspos("TPG2",1,"TPC ",0.,0.,z0,0,"ONLY");
  gMC->Gspos("TPG2",2,"TPC ",0.,0.,-z0,0,"ONLY");


  //---------------------------------------------------------
  //  central wheel  6 (radial direction) x 4 (along z) cm2
  //---------------------------------------------------------

  dm[0] = 140.;
  dm[1] = 146.;
  dm[2] = 2.;

  gMC->Gsvolu("TPWC","TUBE",idtmed[0],dm,3);

  dm[0] = dm[0] + 2.;
  dm[1] = dm[1] - 2.;
  dm[2] = dm[2] - 1.;

  gMC->Gsposp("TPWI",2,"TPWC",0.,0.,0.,0,"ONLY",dm,3);

  z0 = z_side - 1.9 - 2.;

  gMC->Gspos("TPWC",1,"TPSG",0.,0.,z0,0,"ONLY");

  //

  gMC->Gsvolu("TPSE","BOX ",idtmed[24],dm,0); // "empty" part of the spoke 

 
  //---------------------------------------------------------
  //  inner spokes (nSectorInner)
  //---------------------------------------------------------

  dm[0] = 0.5*(139.9-82.1);
  dm[1] = 3.;
  dm[2] = 2.;

  Float_t x1 = dm[0]+82.;

  gMC->Gsvolu("TPSI","BOX",idtmed[0],dm,3);

  dm[1] = dm[1]-1.;
  dm[2] = dm[2]-1.;

  gMC->Gsposp("TPSE",1,"TPSI",0.,0.,0.,0,"ONLY",dm,3);

  for(ns=0;ns<nInnerSector;ns++){

    phi1 = 0.5*InnerOpenAngle + ns*InnerOpenAngle + InnerAngleShift;
    theta1=90.;
    phi1 *=kRaddeg;

    phi1 = (Float_t)TMath::Nint(phi1);
    if(phi1>360.) phi1 -= 360.;    

    phi2 = phi1+90.;
    if(phi2>360.) phi2 -= 360.;
    theta2=90.;
    phi3=0.;
    theta3=0.;

    alpha = phi1 * kDegrad;
    x     = x1 * TMath::Cos(alpha);
    y     = x1 * TMath::Sin(alpha);    

   AliMatrix(idrotm[nRotMat],theta1,phi1,theta2,phi2,theta3,phi3);

   gMC->Gspos("TPSI",ns+1,"TPSG",x,y,z0,idrotm[nRotMat],"ONLY");  

   nRotMat++;

  }

  //-------------------------------------------------------------
  // outer spokes (nSectorOuter)
  //-------------------------------------------------------------

  dm[0] = 0.5*(257.9-146.1);
  dm[1] = 3.;
  dm[2] = 2.;

  x1 = dm[0] + 146.;

  gMC->Gsvolu("TPSO","BOX ",idtmed[0],dm,3);

  dm[1] = dm[1] - 1.;
  dm[2] = dm[2] - 1.;

  gMC->Gsposp("TPSE",2,"TPSO",0.,0.,0.,0,"ONLY",dm,3);

  for(ns=0;ns<nOuterSector;ns++){

    phi1 = 0.5*OuterOpenAngle + ns*OuterOpenAngle + OuterAngleShift;
    theta1=90.;
    phi1 *=kRaddeg;

    phi1 = (Float_t)TMath::Nint(phi1);
    if(phi1>360.) phi1 -= 360.;

    phi2 = phi1+90.;
    if(phi2>360.) phi2 -= 360.;
    theta2=90.;
    phi3=0.;
    theta3=0.;

    alpha = phi1 * kDegrad;
    x     = x1 * TMath::Cos(alpha);
    y     = x1 * TMath::Sin(alpha);    

   AliMatrix(idrotm[nRotMat],theta1,phi1,theta2,phi2,theta3,phi3);

   gMC->Gspos("TPSO",ns+1,"TPSG",x,y,z0,idrotm[nRotMat],"ONLY");  

   nRotMat++;

  }  
  

  
  // -------------------------------------------------------- 
  //         put the readout chambers into the TPC 
  // -------------------------------------------------------- 

  theta1 = 90.;
  phi1   = 0.;
  theta2 = 90.;
  phi2   = 270.;
  theta3 = 180.;
  phi3   = 0.;
  
  AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
  
  z0 = z_side + 250.;
  
  gMC->Gspos("TPSG", 1, "TPC ", 0, 0, z0, 0, "ONLY");
  gMC->Gspos("TPSG", 2, "TPC ", 0, 0, -z0, idrotm[nRotMat], "ONLY");
  
  gMC->Gspos("TPC ", 1, "ALIC", 0, 0, 0, 0, "ONLY");

  //----------------------------------------------------
  //  Inner vessel and HV degrader
  //----------------------------------------------------

  dm[0] = 0.;
  dm[1] = 360.;
  dm[2] = 4.;
  
  dm[3] = -250.;
  dm[4] = 74.4;
  dm[5] = 76.;

  dm[6] = -64.5;
  dm[7] = 50.;
  dm[8] = 76.;

  dm[9] = -64.5;
  dm[10] = 50.;
  dm[11] = 76.;

  dm[12] = 250.;
  dm[13] = 74.4;
  dm[14] = 76.;

  gMC->Gsvolu("TPVD", "PCON", idtmed[12], dm, 15); // CO2

  // cone parts

  dm[0] = 0.;
  dm[1] = 360.;
  dm[2] = 2.;

  dm[3] = 64.5;
  dm[4] = 50.;
  dm[5] = 51.6;
 
  dm[6] = 250.;
  dm[7] = 74.4;
  dm[8] = 76.;


  gMC->Gsvolu("TIVC","PCON",idtmed[11],dm,9); // C-fibre

  gMC->Gspos("TIVC",1,"TPVD",0.,0.,0.,0,"ONLY");
  gMC->Gspos("TIVC",2,"TPVD",0.,0.,0.,idrotm[nRotMat],"ONLY");

  // barrel part

  dm[0] = 50.;
  dm[1] = 50.5;
  dm[2] = 32.25;

  gMC->Gsvolu("TIVB","TUBE",idtmed[9],dm,3);

  gMC->Gspos("TIVB",1,"TPVD",0.,0.,0.,0,"ONLY");

  gMC->Gspos("TPVD",1,"ALIC",0.,0.,0.,0,"ONLY");


  // --------------------------------------------------- 
  //               volumes ordering 
  // ---------------------------------------------------

  gMC->Gsord("TGAS", 6);
  gMC->Gsord("TPSG", 6); 

  

} // end of function
 
//_____________________________________________________________________________
void AliTPCv2::DrawDetector()
{
  //
  // Draw a shaded view of the Time Projection Chamber version 1
  //

  // Set everything unseen
  gMC->Gsatt("*", "seen", -1);
  // 
  // Set ALIC mother transparent
  gMC->Gsatt("ALIC","SEEN",0);
  //
  // Set the volumes visible
  gMC->Gsatt("TPC","SEEN",0);
  gMC->Gsatt("TGAS","SEEN",0);
  gMC->Gsatt("TPSG","SEEN",0);
  gMC->Gsatt("TPHV","SEEN",1);
  gMC->Gsatt("TPMH","SEEN",1);
  gMC->Gsatt("TPEC","SEEN",0);
  gMC->Gsatt("TRCS","SEEN",1);
  gMC->Gsatt("TRCL","SEEN",1);
  gMC->Gsatt("TPWL","SEEN",1);
  gMC->Gsatt("TPWI","SEEN",1);
  gMC->Gsatt("TPWS","SEEN",1);
  gMC->Gsatt("TPW1","SEEN",1);
  gMC->Gsatt("TPS1","SEEN",1);
  gMC->Gsatt("TPS2","SEEN",1);
  gMC->Gsatt("TPG1","SEEN",1);
  gMC->Gsatt("TPG2","SEEN",1);
  gMC->Gsatt("TPWC","SEEN",1);
  gMC->Gsatt("TPSI","SEEN",1); 
  gMC->Gsatt("TPSO","SEEN",1);
  gMC->Gsatt("TPCO","SEEN",1);
  gMC->Gsatt("TPOV","SEEN",1);
  gMC->Gsatt("TPVD","SEEN",1);
  //
  gMC->Gdopt("hide", "on");
  gMC->Gdopt("shad", "on");
  gMC->Gsatt("*", "fill", 7);
  gMC->SetClipBox(".");
  gMC->SetClipBox("*", 0, 1000, -1000, 1000, -1000, 1000);
  gMC->DefaultRange();
  gMC->Gdraw("alic", 40, 30, 0, 12, 9.5, .025, .025);
  gMC->Gdhead(1111, "Time Projection Chamber");
  gMC->Gdman(18, 4, "MAN");
  gMC->Gdopt("hide","off");
}

//_____________________________________________________________________________
void AliTPCv2::CreateMaterials()
{
  //
  // Define materials for version 2 of the Time Projection Chamber
  //

  //
  // Increase maximum number of steps
  gMC->SetMaxNStep(30000);
  //
  AliTPC::CreateMaterials();
}

//_____________________________________________________________________________
void AliTPCv2::Init()
{
  //
  // Initialises version 2 of the TPC after that it has been built
  //
  Int_t *idtmed = fIdtmed->GetArray()-399;
  AliTPC::Init();
  fIdSens1=gMC->VolId("TLGA"); // L-sector
  fIdSens2=gMC->VolId("TSGA"); // S-sector 
  fIdSens3=gMC->VolId("TSST"); // strip - S-sector (not always used)
  fIdSens4=gMC->VolId("TLST"); // strip - S-sector (not always used)

  gMC->SetMaxNStep(30000); // max. number of steps increased

  gMC->Gstpar(idtmed[403],"LOSS",5);

  printf("*** TPC version 2 initialized ***\n");
  printf("Maximum number of steps = %d\n",gMC->GetMaxNStep());

  //
  
}

//_____________________________________________________________________________
void AliTPCv2::StepManager()
{
  //
  // Called for every step in the Time Projection Chamber
  //

  //
  // parameters used for the energy loss calculations
  //
  const Float_t prim = 14.35; // number of primary collisions per 1 cm
  const Float_t poti = 20.77e-9; // first ionization potential for Ne/CO2
  const Float_t w_ion = 35.97e-9; // energy for the ion-electron pair creation 

  //  const Float_t prim = 17.65;
  //  const Float_t poti = 19.02e-9;
  // const Float_t w_ion = 33.06e-9;
 
 
  const Float_t big = 1.e10;

  Int_t id,copy;
  Float_t hits[4];
  Int_t vol[2];  
  TClonesArray &lhits = *fHits;
  TLorentzVector pos;

  AliTPCParam *fTPCParam = &(fDigParam->GetParam());
  
  vol[1]=0;

  //

  gMC->SetMaxStep(big);
  
  if(!gMC->IsTrackAlive()) return; // particle has disappeared
  
  Float_t charge = gMC->TrackCharge();
  
  if(TMath::Abs(charge)<=0.) return; // take only charged particles
  
  
  id=gMC->CurrentVolID(copy);
  
  // Check the sensitive volume
  
  if(id == fIdSens1) 
    {
      vol[0] = copy + fTPCParam->GetNInnerSector()-1; // L-sector number
    }
  else if(id == fIdSens2) 
    {
      vol[0] = copy-1; // S-sector number 
    }
  else if(id == fIdSens3 && gMC->IsTrackEntering())
    {
      vol[1] = copy-1;  // row number  
      id = gMC->CurrentVolOffID(1,copy);
      vol[0] = copy-1; // sector number (S-sector)
      
      gMC->TrackPosition(pos);
      hits[0]=pos[0];
      hits[1]=pos[1];
      hits[2]=pos[2];
      hits[3]=0.; // this hit has no energy loss
      new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
    }
  else if(id == fIdSens4 && gMC->IsTrackEntering())
    {
      vol[1] = copy-1; // row number 
      id = gMC->CurrentVolOffID(1,copy);
      vol[0] = copy+fTPCParam->GetNInnerSector()-1; // sector number (L-sector)
      
      gMC->TrackPosition(pos);
      hits[0]=pos[0];
      hits[1]=pos[1];
      hits[2]=pos[2];
      hits[3]=0.; // this hit has no energy loss
      new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
    }
  else return;
  
  //
  //  charged particle is in the sensitive volume
  //
  
  if(gMC->TrackStep() > 0) {
    
    Int_t nel = (Int_t)(((gMC->Edep())-poti)/w_ion) + 1;
    nel=TMath::Min(nel,300); // 300 electrons corresponds to 10 keV
    
    gMC->TrackPosition(pos);
    hits[0]=pos[0];
    hits[1]=pos[1];
    hits[2]=pos[2];
    hits[3]=(Float_t)nel;
    
    // Add this hit
    
    new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
    
  } 
  
  // Stemax calculation for the next step
  
  Float_t pp;
  TLorentzVector mom;
  gMC->TrackMomentum(mom);
  Float_t ptot=mom.Rho();
  Float_t beta_gamma = ptot/gMC->TrackMass();
  
  if(gMC->IdFromPDG(gMC->TrackPid()) <= 3 && ptot > 0.002)
    { 
      pp = prim*1.58; // electrons above 20 MeV/c are on the plateau!
    }
  else
    {
      pp=prim*BetheBloch(beta_gamma);    
      if(TMath::Abs(charge) > 1.) pp *= (charge*charge);
    }
  
  Float_t random[1];
  gMC->Rndm(random,1); // good, old GRNDM from Geant3
  
  Double_t rnd = (Double_t)random[0];
  
  gMC->SetMaxStep(-TMath::Log(rnd)/pp);
  
}

//_____________________________________________________________________________
Float_t AliTPCv2::BetheBloch(Float_t bg)
{
  //
  // Bethe-Bloch energy loss formula
  //
  const Double_t p1=0.76176e-1;
  const Double_t p2=10.632;
  const Double_t p3=0.13279e-4;
  const Double_t p4=1.8631;
  const Double_t p5=1.9479;

  Double_t dbg = (Double_t) bg;

  Double_t beta = dbg/TMath::Sqrt(1.+dbg*dbg);

  Double_t aa = TMath::Power(beta,p4);
  Double_t bb = TMath::Power(1./dbg,p5);

  bb=TMath::Log(p3+bb);
  
  return ((Float_t)((p2-aa-bb)*p1/aa));
}