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[u/mrichter/AliRoot.git] / FMD / AliFMDGeometryBuilder.cxx

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 * 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.                  *
 **************************************************************************/
/* $Id$ */
/** @file    AliFMDGeometryBuilder.cxx
    @author  Christian Holm Christensen <cholm@nbi.dk>
    @date    Mon Mar 27 12:41:17 2006
    @brief   Class to build the FMD geometry 
*/
//____________________________________________________________________
//                                                                          
// Builder of FMD geometry. 
//
// This class takes care of actually building the geometry using the 
// TGeo classes.  Various parameters are fecthed from the
// AliFMDGeometry manager.  
// Forward Multiplicity Detector based on Silicon wafers. This class
// contains the base procedures for the Forward Multiplicity detector
// Detector consists of 3 sub-detectors FMD1, FMD2, and FMD3, each of
// which has 1 or 2 rings of silicon sensors. 
//                                                       
// 
#include "AliFMDGeometryBuilder.h"	// ALIFMDGEOSIMULATOR_H
#include "AliFMDGeometry.h"	// ALIFMDGEOMETRY_H
#include "AliFMDDetector.h"	// ALIFMDDETECTOR_H
#include "AliFMDRing.h"		// ALIFMDRING_H
#include "AliFMD1.h"		// ALIFMD1_H
#include "AliFMD2.h"		// ALIFMD2_H
#include "AliFMD3.h"		// ALIFMD3_H
// #include "AliFMD.h"		// ALIFMD_H
#include "AliLog.h"		// ALILOG_H
#include <TGeoVolume.h>		// ROOT_TGeoVolume
#include <TGeoTube.h>		// ROOT_TGeoTube
//#include <TGeoPcon.h>		// ROOT_TGeoPcon
//#include <TGeoMaterial.h>	// ROOT_TGeoMaterial
//#include <TGeoMedium.h>		// ROOT_TGeoMedium
#include <TGeoXtru.h>		// ROOT_TGeoXtru
//#include <TGeoPolygon.h>	// ROOT_TGeoPolygon
#include <TGeoTube.h>		// ROOT_TGeoTube
#include <TGeoManager.h>	// ROOT_TGeoManager
#include <TVector2.h>		// ROOT_TVector2
#include <TArrayD.h>		// ROOT_TArrayD

//====================================================================
ClassImp(AliFMDGeometryBuilder)
#if 0
  ; // This is here to keep Emacs for indenting the next line
#endif

//____________________________________________________________________
const Char_t* AliFMDGeometryBuilder::fgkActiveName	= "F%cAC";
const Char_t* AliFMDGeometryBuilder::fgkSectorName	= "F%cSC";
const Char_t* AliFMDGeometryBuilder::fgkStripName	= "F%cST";
const Char_t* AliFMDGeometryBuilder::fgkSensorName	= "F%cSE";
const Char_t* AliFMDGeometryBuilder::fgkPCBName	        = "F%cPB";
const Char_t* AliFMDGeometryBuilder::fgkCuName	        = "F%cCU";
const Char_t* AliFMDGeometryBuilder::fgkChipName	= "F%cCH";
const Char_t* AliFMDGeometryBuilder::fgkLongLegName	= "F%cLL";
const Char_t* AliFMDGeometryBuilder::fgkShortLegName	= "F%cSL";
const Char_t* AliFMDGeometryBuilder::fgkFrontVName	= "F%cFH";
const Char_t* AliFMDGeometryBuilder::fgkBackVName	= "F%cBH";
const Char_t* AliFMDGeometryBuilder::fgkRingTopName	= "F%cTV";
const Char_t* AliFMDGeometryBuilder::fgkRingBotName	= "F%cBV";
const Char_t* AliFMDGeometryBuilder::fgkHCName		= "F%dH%c";
const Char_t* AliFMDGeometryBuilder::fgkIHCName		= "F%dI%c";
const Char_t* AliFMDGeometryBuilder::fgkNoseName        = "F3SN";
const Char_t* AliFMDGeometryBuilder::fgkBackName        = "F3SB";
const Char_t* AliFMDGeometryBuilder::fgkBeamName        = "F3SL";
const Char_t* AliFMDGeometryBuilder::fgkFlangeName      = "F3SF";
const Char_t* AliFMDGeometryBuilder::fgkFMDName         = "F%dM%c";

//____________________________________________________________________
AliFMDGeometryBuilder::AliFMDGeometryBuilder() 
  : fDetailed(kTRUE),
    fUseAssembly(kTRUE),
    fSi(0),
    fC(0),
    fAl(0),
    fPCB(0),
    fChip(0),
    fPlastic(0)
{
  // Default constructor
  fActiveId.Set(2);
}

//____________________________________________________________________
AliFMDGeometryBuilder::AliFMDGeometryBuilder(Bool_t detailed) 
  : TTask("FMD", "Geometry builder"),
    fDetailed(detailed),
    fUseAssembly(kTRUE),
    fSi(0),
    fC(0),
    fAl(0),
    fPCB(0),
    fChip(0),
    fPlastic(0)
{
  // Normal constructor
  // 
  // Parameters: 
  // 
  //      fmd		Pointer to AliFMD object 
  //      detailed      Whether to make a detailed simulation or not 
  // 
  fActiveId.Set(2);
}


//____________________________________________________________________
TGeoVolume*
AliFMDGeometryBuilder::RingGeometry(AliFMDRing* r) 
{
  // Setup the geometry of a ring.    The defined TGeoVolume is
  // returned, and should be used when setting up the rest of the
  // volumes. 
  // 
  // 
  // Parameters:
  //
  //     r		Pointer to ring geometry object 
  // 
  // Returns:
  //    pointer to ring volume 
  //
  if (!r) { 
    AliError("Didn't get a ring object");
    return 0;
  }
  Char_t      id       = r->GetId();
  Double_t    siThick  = r->GetSiThickness();
  const Int_t knv      = r->GetNVerticies();
  TVector2*   a        = r->GetVertex(5);
  TVector2*   b        = r->GetVertex(3);
  TVector2*   c        = r->GetVertex(4);
  Double_t    theta    = r->GetTheta();
  Double_t    off      = (TMath::Tan(TMath::Pi() * theta / 180) 
			  * r->GetBondingWidth());
  Double_t    rmax     = b->Mod();
  Double_t    rmin     = r->GetLowR();
  Double_t    pcbThick = r->GetPrintboardThickness();
  Double_t    cuThick  = r->GetCopperThickness();
  Double_t    chipThick= r->GetChipThickness();
  Double_t    modSpace = r->GetModuleSpacing();
  Double_t    legr     = r->GetLegRadius();
  Double_t    legl     = r->GetLegLength();
  Double_t    legoff   = r->GetLegOffset();
  Int_t       ns       = r->GetNStrips();
  Double_t    stripoff = a->Mod();
  Double_t    dstrip   = (rmax - stripoff) / ns;
  Double_t    space    = r->GetSpacing();
  TArrayD xs(knv);
  TArrayD ys(knv);
  for (Int_t i = 0; i < knv; i++) {
    // Reverse the order 
    TVector2* vv = r->GetVertex(knv - 1 - i);
    if (!vv) {
      AliError(Form("Failed to get vertex # %d", knv - 1 - i));
      continue;
    }
    xs[i] = vv->X();
    ys[i] = vv->Y();
  }
  
  // Shape of actual sensor 
  TGeoXtru* sensorShape = new TGeoXtru(2);
  sensorShape->DefinePolygon(knv, xs.fArray, ys.fArray);
  sensorShape->DefineSection(0, - siThick/2);
  sensorShape->DefineSection(1, siThick/2);
  TGeoVolume* sensorVolume = new TGeoVolume(Form(fgkSensorName, id), 
					    sensorShape, fSi);
  sensorVolume->VisibleDaughters(kFALSE);
  Int_t sid = sensorVolume->GetNumber();
  fSectorOff   = -1;
  fModuleOff   = 1;
  fRingOff     = 2;
  fDetectorOff = 3;
  if (fDetailed) {
    fSectorOff   = 1;
    fModuleOff   = 3;
    fRingOff     = 4;
    fDetectorOff = 5;
    // Virtual volume shape to divide - This volume is only defined if
    // the geometry is set to be detailed. 
    TGeoTubeSeg* activeShape = new TGeoTubeSeg(rmin, rmax, siThick/2, 
					       - theta, theta);
    TGeoVolume* activeVolume = new TGeoVolume(Form(fgkActiveName, id),
					      activeShape,fSi);
    TGeoVolume* sectorVolume = activeVolume->Divide(Form(fgkSectorName,id), 
						      2, 2, -theta,0,0,"N");
    TGeoVolume* stripVolume  = sectorVolume->Divide(Form(fgkStripName, id), 
						    1, ns, stripoff, dstrip, 
						    0, "SX");
    sid = stripVolume->GetNumber();
    sensorVolume->AddNodeOverlap(activeVolume, 0);
  }
  
  switch (id) {
  case 'i': case 'I': fActiveId[0] = sid; break;
  case 'o': case 'O': fActiveId[1] = sid; break;
  }

  // Shape of Printed circuit Board 
  for (Int_t i = 0;       i < knv / 2; i++) ys[i] -= off;
  for (Int_t i = knv / 2; i < knv;     i++) ys[i] += off;
  TGeoXtru* pcbShape         = new TGeoXtru(2);
  pcbShape->DefinePolygon(knv, xs.fArray, ys.fArray);
  pcbShape->DefineSection(0, - pcbThick/2);
  pcbShape->DefineSection(1, pcbThick/2);
  TGeoVolume* pcbVolume      = new TGeoVolume(Form(fgkPCBName, id), 
					      pcbShape, fPCB);

  // Copper layer
  TGeoXtru* cuShape       = new TGeoXtru(2);
  cuShape->DefinePolygon(6, xs.fArray, ys.fArray);
  cuShape->DefineSection(0, - cuThick/2);
  cuShape->DefineSection(1, cuThick/2);
  TGeoVolume* cuVolume    = new TGeoVolume(Form(fgkCuName,id),cuShape,fCopper);

  // Chip layer
  TGeoXtru*   chipShape   = new TGeoXtru(2);
  chipShape->DefinePolygon(6, xs.fArray, ys.fArray);
  chipShape->DefineSection(0, - chipThick/2);
  chipShape->DefineSection(1, chipThick/2);
  TGeoVolume* chipVolume = new TGeoVolume(Form(fgkChipName,id),
					  chipShape,fChip);

  // Short leg shape 
  TGeoTube*   shortLegShape  = new TGeoTube(0, legr, legl / 2);
  TGeoVolume* shortLegVolume = new TGeoVolume(Form(fgkShortLegName, id), 
					      shortLegShape, fPlastic);

  // Long leg shape
  TGeoTube*   longLegShape   = new TGeoTube(0, legr, (legl + modSpace) / 2);
  TGeoVolume* longLegVolume  = new TGeoVolume(Form(fgkLongLegName, id), 
					      longLegShape, fPlastic);
  
  
  // Back container volume 
  TGeoVolume* backVolume     = new TGeoVolumeAssembly(Form(fgkBackVName, id));
  Double_t x = 0;
  Double_t y = 0;
  Double_t z = pcbThick / 2;
  backVolume->AddNode(pcbVolume, 0, new TGeoTranslation(x,y,z));
  z          += (pcbThick + cuThick) / 2;
  backVolume->AddNode(cuVolume, 0, new TGeoTranslation(0, 0, z));
  z          += (cuThick + chipThick) / 2;
  backVolume->AddNode(chipVolume, 0, new TGeoTranslation(0, 0, z));
  x          =  a->X() + legoff + legr;
  y          =  0;
  z          += pcbThick / 2 + legl / 2;
  backVolume->AddNode(shortLegVolume, 0, new TGeoTranslation(x,y,z));
  x          =  c->X();
  y          =  c->Y() - legoff - legr - off;
  backVolume->AddNode(shortLegVolume, 1, new TGeoTranslation(x,y,z));
  y          =  -y;
  backVolume->AddNode(shortLegVolume, 2, new TGeoTranslation(x,y,z));

  // Front container volume 
  TGeoVolume* frontVolume    = new TGeoVolumeAssembly(Form(fgkFrontVName, id));
  x         =  0;
  y         =  0;
  z         =  pcbThick / 2;
  frontVolume->AddNode(pcbVolume, 1, new TGeoTranslation(x,y,z));
  z          += (pcbThick + cuThick) / 2;
  frontVolume->AddNode(cuVolume, 0, new TGeoTranslation(0, 0, z));
  z          += (cuThick + chipThick) / 2;
  frontVolume->AddNode(chipVolume, 0, new TGeoTranslation(0, 0, z));
  x         =  a->X() + legoff + legr;
  y         =  0;
  z         += pcbThick / 2 + (legl + modSpace)/ 2;
  frontVolume->AddNode(longLegVolume, 0, new TGeoTranslation(x,y,z));
  x         =  c->X();
  y         =  c->Y() - legoff - legr - off;
  frontVolume->AddNode(longLegVolume, 1, new TGeoTranslation(x,y,z));
  y         =  -y;
  frontVolume->AddNode(longLegVolume, 2, new TGeoTranslation(x,y,z));
  
  // Half ring mother volumes. 
  TGeoVolume* ringTopVolume = new TGeoVolumeAssembly(Form(fgkRingTopName,id));
  TGeoVolume* ringBotVolume = new TGeoVolumeAssembly(Form(fgkRingBotName,id));
  TGeoVolume* halfRing      = ringTopVolume;

  // Adding modules to half-rings
  Int_t    nmod =  r->GetNModules();
  AliDebug(10, Form("making %d modules in ring %c", nmod, id));
  for (Int_t i = 0; i < nmod; i++) {
    if (i == nmod / 2) halfRing = ringBotVolume;
    Bool_t      front =  (i % 2 == 0);
    Double_t    z1    =  siThick / 2 + (i % 2) * modSpace;
    Double_t    z2    =  z1 + siThick / 2 + space;
    Double_t    th    =  (2 * i + 1) * theta;
    TGeoVolume* vol   =  (front ? frontVolume : backVolume);
    AliDebug(20, Form("Placing copy %d of %s and %s in %s at z=%f and %f, "
		      "and theta=%f", i, sensorVolume->GetName(), 
		      vol->GetName(), halfRing->GetName(), z1, z2, th));
    TGeoMatrix* mat1  =  new TGeoCombiTrans(0,0,z1,0); 
    mat1->RotateZ(th);
    halfRing->AddNode(sensorVolume, i, mat1);
    TGeoMatrix* mat2  =  new TGeoCombiTrans(0,0,z2,0); 
    mat2->RotateZ(th);
    halfRing->AddNode(vol, i, mat2);
  }

  return 0;
}

//____________________________________________________________________
TGeoVolume*
AliFMDGeometryBuilder::DetectorGeometry(AliFMDDetector* d, 
					TGeoVolume* topMother, 
					TGeoVolume* botMother, 
					Double_t    zMother, 
					TGeoVolume* innerTop, 
					TGeoVolume* innerBot, 
					TGeoVolume* outerTop, 
					TGeoVolume* outerBot) 
{
  // Common stuff for setting up the FMD1, FMD2, and FMD3 geometries.
  // This includes putting the Honeycomb support plates and the rings
  // into the mother volumes.   
  // 
  // Parameeters:
  //	d	  The detector geometry to use 
  //	mother	  The mother volume of the detector 
  //    zmother	  The midpoint in global coordinates of detector vol.
  //	inner	  Pointer to inner ring volume 
  //    outer	  Pointer to outer ring volume
  //
  // Returns:
  //    Pointer to mother (detector volume) 
  // 
  if (!d) return 0;
  // Loop over the defined rings 
  for (int i = 0; i < 2; i++) {
    AliFMDRing* r     = 0;
    Double_t    lowr  = 0;
    Double_t    highr = 0;
    Double_t    rz    = 0;
    TGeoVolume* tvol  = 0;
    TGeoVolume* bvol  = 0;
    switch (i) {
    case 0: 
      r      = d->GetInner();
      lowr   = d->GetInnerHoneyLowR();
      highr  = d->GetInnerHoneyHighR();
      rz     = d->GetInnerZ();
      tvol   = innerTop;
      bvol   = innerBot;
      break;
    case 1: 
      r      = d->GetOuter();
      lowr   = d->GetOuterHoneyLowR();
      highr  = d->GetOuterHoneyHighR();
      rz     = d->GetOuterZ();
      tvol   = outerTop;
      bvol   = outerBot;
      break;
    }
    if (!r) continue;
    Char_t   c       = r->GetId();
    Int_t    id      = d->GetId();
    Double_t hcThick = d->GetHoneycombThickness();
    Double_t alThick = d->GetAlThickness();
    Double_t z       = TMath::Abs(rz - zMother);

    // Place ring in mother volume
    // TGeoMatrix*matrix=new TGeoTranslation(Form("FMD%d%c trans",id,c),0,0,0);
    AliDebug(5, Form("Placing volumes %s and %s in %s and %s at z=%f", 
		     tvol->GetName(), bvol->GetName(), 
		     topMother->GetName(), botMother->GetName(), z));
    topMother->AddNode(tvol, Int_t(c), new TGeoTranslation(0,0,z));
    botMother->AddNode(bvol, Int_t(c), new TGeoTranslation(0,0,z));

    // Top of Honeycomb
    TGeoTubeSeg* hcSha = new TGeoTubeSeg(lowr, highr, hcThick/2, 0, 180);
    TGeoVolume*  hcVol = new TGeoVolume(Form(fgkHCName,id,c),hcSha,fAl);
    // Air in top of honeycomb
    TGeoTubeSeg* ihcSha = new TGeoTubeSeg(lowr+alThick, highr - alThick, 
					     (hcThick-alThick)/2, 0, 180);
    TGeoVolume*  ihcVol = new TGeoVolume(Form(fgkIHCName,id,c),ihcSha,fAir);
    hcVol->AddNode(ihcVol, 0);
    hcVol->VisibleDaughters(kFALSE);    
    hcVol->SetVisibility(kTRUE);

    z += (r->GetSiThickness() + 
	  r->GetSpacing() + 
	  r->GetPrintboardThickness() + 
	  r->GetCopperThickness() + 
	  r->GetChipThickness() + 
	  r->GetModuleSpacing() +
	  r->GetLegLength() + 
	  hcThick / 2); 

    AliDebug(15, Form("Placing a copy of %s in %s and %s at z=%f", 
		      hcVol->GetName(), topMother->GetName(), 
		      botMother->GetName(), z));
    // Add to top 
    topMother->AddNode(hcVol, 0, new TGeoTranslation(0, 0, z));

    // Add to bottom
    TGeoMatrix*   bhcMatrix = new TGeoCombiTrans(0,0,z,0);
    bhcMatrix->RotateZ(180);
    botMother->AddNode(hcVol, 1, bhcMatrix);
  }
  return 0;
}

//____________________________________________________________________
TGeoVolume*
AliFMDGeometryBuilder::FMD1Geometry(AliFMD1* fmd1, 
				    TGeoVolume* innerTop, 
				    TGeoVolume* innerBot) 
{
  // Setup the FMD1 geometry.  The FMD1 only has one ring, and no
  // special support as it is at the momement. 
  // 
  // See also AliFMDGeometryBuilder::DetectorGeometry 
  // 
  if (!fmd1 || !innerTop || !innerBot) return 0;
  Double_t    z             = fmd1->GetInnerZ();  
  TGeoVolume* fmd1TopVolume = new TGeoVolumeAssembly(Form(fgkFMDName, 
							  fmd1->GetId(), 'T'));
  TGeoVolume* fmd1BotVolume = new TGeoVolumeAssembly(Form(fgkFMDName, 
							  fmd1->GetId(), 'B'));
  
  // Basic detector geometry 
  DetectorGeometry(fmd1, fmd1TopVolume, fmd1BotVolume, z, 
		   innerTop, innerBot, 0, 0);

  // Must add this after filling the assembly.
  TGeoVolume* top    = gGeoManager->GetVolume("ALIC");
  TGeoMatrix* matrix = new TGeoTranslation("FMD1 trans", 0, 0, z);
  AliDebug(5, Form("Placing volumes %s and %s in ALIC at z=%f", 
		   fmd1TopVolume->GetName(), fmd1BotVolume->GetName(), z));
  top->AddNode(fmd1TopVolume, fmd1->GetId(), matrix);
  top->AddNode(fmd1BotVolume, fmd1->GetId(), matrix);

  return 0;
}

//____________________________________________________________________
TGeoVolume*
AliFMDGeometryBuilder::FMD2Geometry(AliFMD2* fmd2, 
				    TGeoVolume* innerTop, 
				    TGeoVolume* innerBot, 
				    TGeoVolume* outerTop,
				    TGeoVolume* outerBot) 
{
  // Setup the FMD2 geometry.  The FMD2 has no
  // special support as it is at the momement. 
  // 
  // See also AliFMDGeometryBuilder::DetectorGeometry 
  // 
  if (!fmd2 || !innerTop || !innerBot || !outerTop || !outerBot) return 0;
  Double_t z                = fmd2->GetOuterZ();
  TGeoVolume* fmd2TopVolume = new TGeoVolumeAssembly(Form(fgkFMDName, 
							  fmd2->GetId(), 'T'));
  TGeoVolume* fmd2BotVolume = new TGeoVolumeAssembly(Form(fgkFMDName, 
							  fmd2->GetId(), 'B'));
  
  DetectorGeometry(fmd2, fmd2TopVolume, fmd2BotVolume, z, 
		   innerTop, innerBot, outerTop, outerBot);

  // Must be done after filling the assemblies 
  TGeoVolume* top = gGeoManager->GetVolume("ALIC");
  TGeoMatrix* matrix = new TGeoTranslation("FMD2 trans", 0, 0, z);
  AliDebug(5, Form("Placing volumes %s and %s in ALIC at z=%f", 
		   fmd2TopVolume->GetName(), fmd2BotVolume->GetName(), z));
  top->AddNode(fmd2TopVolume, fmd2->GetId(), matrix);
  top->AddNode(fmd2BotVolume, fmd2->GetId(), matrix);

  return 0;
}
  
//____________________________________________________________________
TGeoVolume*
AliFMDGeometryBuilder::FMD3Geometry(AliFMD3* fmd3, 
				    TGeoVolume* innerTop, 
				    TGeoVolume* innerBot, 
				    TGeoVolume* outerTop,
				    TGeoVolume* outerBot) 
{
  // Setup the FMD3 geometry.  The FMD2 has a rather elaborate support
  // structure, as the support will also support the vacuum
  // beam-pipe. 
  // 
  // See also AliFMDGeometryBuilder::DetectorGeometry 
  // 
  if (!fmd3 || !innerTop || !innerBot || !outerTop || !outerBot) return 0;
  Double_t nlen    = fmd3->GetNoseLength();
  Double_t nz      = fmd3->GetNoseZ();
  Double_t noser1  = fmd3->GetNoseLowR();
  Double_t noser2  = fmd3->GetNoseHighR();
  Double_t conel   = fmd3->GetConeLength();
  Double_t backl   = fmd3->GetBackLength();
  Double_t backr1  = fmd3->GetBackLowR();
  Double_t backr2  = fmd3->GetBackHighR();
  Double_t zdist   = conel -  backl - nlen;
  Double_t tdist   = backr2 - noser2;
  Double_t beaml   = TMath::Sqrt(zdist * zdist + tdist * tdist);
  Double_t theta   = -180. * TMath::ATan2(tdist, zdist) / TMath::Pi();
  Double_t flanger = fmd3->GetFlangeR();
  Double_t z       = fmd3->GetInnerZ(); // fmd3->GetZ();
  Double_t zi;

  TGeoVolume* fmd3TopVolume = new TGeoVolumeAssembly(Form(fgkFMDName, 
							  fmd3->GetId(), 'T'));
  TGeoVolume* fmd3BotVolume = new TGeoVolumeAssembly(Form(fgkFMDName, 
							  fmd3->GetId(), 'B'));

  
  DetectorGeometry(fmd3, fmd3TopVolume, fmd3BotVolume, z, 
		   innerTop, innerBot, outerTop, outerBot);


  // Nose volume 
  TGeoTubeSeg* noseShape = new TGeoTubeSeg(noser1, noser2, nlen / 2, 0, 180);
  TGeoVolume* noseVolume = new TGeoVolume(fgkNoseName, noseShape, fC);
  zi                     = -nz + nlen / 2 + z;

  fmd3TopVolume->AddNode(noseVolume, 0, new TGeoTranslation(0, 0, zi));
  TGeoMatrix* nmatrix    = new TGeoCombiTrans(0, 0, zi, 0); 
  nmatrix->RotateZ(180);
  fmd3BotVolume->AddNode(noseVolume, 1, nmatrix);
  
  // Back
  TGeoTubeSeg* backShape = new TGeoTubeSeg(backr1, backr2, backl / 2, 0, 180);
  TGeoVolume* backVolume = new TGeoVolume(fgkBackName, backShape, fC);
  zi                     = -nz + conel - backl / 2 + z;
  fmd3TopVolume->AddNode(backVolume, 0, new TGeoTranslation(0, 0, zi));
  TGeoMatrix* bmatrix    = new TGeoCombiTrans(0, 0, zi, 0);
  bmatrix->RotateZ(180);
  fmd3BotVolume->AddNode(backVolume, 1, bmatrix);
  
  
  Int_t n;
  Double_t r;
  // The flanges 
  TGeoBBox* flangeShape = new TGeoBBox((flanger - backr2) / 2, 
				       fmd3->GetBeamWidth() / 2,
				       backl / 2);
  TGeoVolume* flangeVolume = new TGeoVolume(fgkFlangeName, flangeShape, fC);
  n                        = fmd3->GetNFlange();
  r                        = backr2 + (flanger - backr2) / 2;
  TGeoVolume* mother       = fmd3TopVolume;
  for (Int_t i = 0; i  < n; i++) {
    if (i >= n / 2) mother = fmd3BotVolume;
    Double_t phi       = 360. / n * i + 180. / n;
    Double_t x         = r * TMath::Cos(TMath::Pi() / 180 * phi);
    Double_t y         = r * TMath::Sin(TMath::Pi() / 180 * phi);
    AliDebug(15, Form("Placing flange %d in %s at (%f,%f,%f) r=%f, phi=%f", 
		      i, mother->GetName(), x, y, zi, r, phi));
    TGeoRotation* rot    = new TGeoRotation;
    rot->RotateZ(phi);
    TGeoMatrix* matrix = new TGeoCombiTrans(x, y, zi, rot);
    mother->AddNode(flangeVolume, i, matrix);
  }

  // The Beams 
  TGeoBBox* beamShape = new TGeoBBox(fmd3->GetBeamThickness() / 2, 
				     fmd3->GetBeamWidth() / 2 - .1,
				     beaml / 2);
  TGeoVolume* beamVolume = new TGeoVolume(fgkBeamName, beamShape, fC);
  n                      = fmd3->GetNBeam();
  r                      = noser2 + tdist / 2;
  zi                     = - nz + nlen + zdist / 2 + z;
  mother                 = fmd3TopVolume;
  for (Int_t i = 0; i  < n; i++) {
    if (i >= n / 2) mother = fmd3BotVolume;
    Double_t phi      = 360. / n * i;
    Double_t x        = r * TMath::Cos(TMath::Pi() / 180 * phi);
    Double_t y        = r * TMath::Sin(TMath::Pi() / 180 * phi);
    TGeoRotation* rot = new TGeoRotation(Form("FMD3 beam rotation %d", i));
    // Order is important
    rot->RotateY(-theta);
    rot->RotateZ(phi);
    TGeoMatrix* matrix = new TGeoCombiTrans(Form("FMD3 beam trans %d", i),
					    x, y, zi, rot);
    mother->AddNode(beamVolume, i, matrix);    
  }
  
  z = fmd3->GetInnerZ();
  TGeoRotation* rot = new TGeoRotation("FMD3 rotatation");
  rot->RotateY(180);
  TGeoVolume* top = gGeoManager->GetVolume("ALIC");
  TGeoMatrix* mmatrix = new TGeoCombiTrans("FMD3 trans", 0, 0, z, rot);
  AliDebug(5, Form("Placing volumes %s and %s in ALIC at z=%f", 
		   fmd3TopVolume->GetName(), fmd3BotVolume->GetName(), z));
  top->AddNode(fmd3TopVolume, fmd3->GetId(), mmatrix);
  top->AddNode(fmd3BotVolume, fmd3->GetId(), mmatrix);

  return 0;
}

//____________________________________________________________________
void
AliFMDGeometryBuilder::Exec(Option_t*) 
{
  // Setup up the FMD geometry. 
  AliDebug(1,  Form("\tGeometry options: %s",
		    (fDetailed  ? "divided into strips" : "one volume")));
  if (!gGeoManager) {
    AliFatal("No TGeoManager defined");
    return;
  }

  fSi      = gGeoManager->GetMedium("FMD_Si$");
  fC       = gGeoManager->GetMedium("FMD_Carbon$");
  fAl      = gGeoManager->GetMedium("FMD_Aluminum$");
  fChip    = gGeoManager->GetMedium("FMD_Si Chip$");
  fAir     = gGeoManager->GetMedium("FMD_Air$");
  fPCB     = gGeoManager->GetMedium("FMD_PCB$");
  fPlastic = gGeoManager->GetMedium("FMD_Plastic$");
  fCopper  = gGeoManager->GetMedium("FMD_Copper$");

  if (!fSi||!fC||!fAl||!fChip||!fAir||!fPCB||!fPlastic||!fCopper) {
    AliError("Failed to get some or all tracking mediums");
    return;
  }    
  AliFMDGeometry* fmd = AliFMDGeometry::Instance();
  AliFMDRing* inner = fmd->GetInner();
  AliFMDRing* outer = fmd->GetOuter();
  RingGeometry(inner);
  RingGeometry(outer);
  TGeoVolume* innerTop = gGeoManager->GetVolume(Form(fgkRingTopName, 
						     inner->GetId()));
  TGeoVolume* innerBot = gGeoManager->GetVolume(Form(fgkRingBotName, 
						     inner->GetId()));
  TGeoVolume* outerTop = gGeoManager->GetVolume(Form(fgkRingTopName, 
						     outer->GetId()));
  TGeoVolume* outerBot = gGeoManager->GetVolume(Form(fgkRingBotName, 
						     outer->GetId()));
  
  FMD1Geometry(fmd->GetFMD1(), innerTop, innerBot);
  FMD2Geometry(fmd->GetFMD2(), innerTop, innerBot, outerTop, outerBot);
  FMD3Geometry(fmd->GetFMD3(), innerTop, innerBot, outerTop, outerBot);
#ifndef USE_PRE_MOVE
  fmd->SetSectorOff(fSectorOff);
  fmd->SetModuleOff(fModuleOff);
  fmd->SetRingOff(fRingOff);
  fmd->SetDetectorOff(fDetectorOff);
  fmd->SetActive(fActiveId.fArray, fActiveId.fN);
#endif
  // fmd->ExtractGeomInfo();
  
}


//____________________________________________________________________
//
// EOF
//