The present commit corresponds to an important change in the way the
[u/mrichter/AliRoot.git] / FMD / AliFMD.cxx
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-///////////////////////////////////////////////////////////////////////////////
-//                                                                           //
-//  Forward Multiplicity Detector                                            //
-//  This class contains the base procedures for the Forward Multiplicity     //
-//  detector                                                                 //
-//                                                                           //
-//Begin_Html
-/*
-<img src="picts/AliFMDClass.gif">
-</pre>
-<br clear=left>
-<font size=+2 color=red>
-<p>The responsible person for this module is
-<a href="mailto:Valeri.Kondratiev@cern.ch">Valeri Kondratiev</a>.
-</font>
-<pre>
+/**************************************************************************
+ * 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    AliFMD.cxx
+    @author  Christian Holm Christensen <cholm@nbi.dk>
+    @date    Sun Mar 26 17:59:18 2006
+    @brief   Implementation of AliFMD base class 
 */
-//End_Html
-//                                                                           //
-//                                                                           //
-///////////////////////////////////////////////////////////////////////////////
-
-#include <TTUBE.h>
-#include <TNode.h>
-#include "AliRun.h"
-#include "AliFMD.h"
+//____________________________________________________________________
+//                                                                          
+// Forward Multiplicity Detector based on Silicon wafers. This class
+// is the driver for especially simulation. 
+//
+// The Forward Multiplicity Detector consists of 3 sub-detectors FMD1,
+// FMD2, and FMD3, each of which has 1 or 2 rings of silicon sensors. 
+//                                                       
+// This is the base class for all FMD manager classes. 
+//                    
+// The actual code is done by various separate classes.   Below is
+// diagram showing the relationship between the various FMD classes
+// that handles the simulation
+//
+//
+//       +----------+   +----------+   
+//       | AliFMDv1 |  | AliFMDv0 |   
+//       +----------+   +----------+   
+//            |              |                    +-----------------+
+//       +----+--------------+                 +--| AliFMDDigitizer |
+//       |                                     |  +-----------------+
+//       |           +---------------------+   |
+//       |        +--| AliFMDBaseDigitizer |<--+
+//       V     1  |  +---------------------+   |
+//  +--------+<>--+                            |  +------------------+
+//  | AliFMD |                                 +--| AliFMDSDigitizer |    
+//  +--------+<>--+                               +------------------+       
+//            1  |  +---------------------+
+//               +--| AliFMDReconstructor |
+//                  +---------------------+
+//
+// *  AliFMD 
+//    This defines the interface for the various parts of AliROOT that
+//    uses the FMD, like AliFMDSimulator, AliFMDDigitizer, 
+//    AliFMDReconstructor, and so on. 
+//
+// *  AliFMDv0
+//    This is a concrete implementation of the AliFMD interface. 
+//    It is the responsibility of this class to create the FMD
+//    geometry.
+//
+// *  AliFMDv1 
+//    This is a concrete implementation of the AliFMD interface. 
+//    It is the responsibility of this class to create the FMD
+//    geometry, process hits in the FMD, and serve hits and digits to
+//    the various clients. 
+//  
+// *  AliFMDSimulator
+//    This is the base class for the FMD simulation tasks.   The
+//    simulator tasks are responsible to implment the geoemtry, and
+//    process hits. 
+//                                                                          
+// *  AliFMDReconstructor
+//    This is a concrete implementation of the AliReconstructor that
+//    reconstructs pseudo-inclusive-multiplicities from digits (raw or
+//    from simulation)
+//
+// Calibration and geometry parameters are managed by separate
+// singleton managers.  These are AliFMDGeometry and
+// AliFMDParameters.  Please refer to these classes for more
+// information on these.
+//
+
+// These files are not in the same directory, so there's no reason to
+// ask the preprocessor to search in the current directory for these
+// files by including them with `#include "..."' 
+#include <TBrowser.h>          // ROOT_TBrowser
+#include <TClonesArray.h>      // ROOT_TClonesArray
+#include <TGeoGlobalMagField.h> // ROOT_TGeoGlobalMagField
+#include <TGeoManager.h>        // ROOT_TGeoManager
+#include <TRotMatrix.h>                // ROOT_TRotMatrix
+#include <TTree.h>             // ROOT_TTree
+#include <TVector2.h>           // ROOT_TVector2 
+#include <TVirtualMC.h>                // ROOT_TVirtualMC
+#include <cmath>                // __CMATH__
+
+#include <AliRunDigitizer.h>   // ALIRUNDIGITIZER_H
+#include <AliLoader.h>         // ALILOADER_H
+#include <AliRun.h>            // ALIRUN_H
+#include <AliMC.h>             // ALIMC_H
+#include <AliMagF.h>           // ALIMAGF_H
+// #include <AliLog.h>         // ALILOG_H
+#include "AliFMDDebug.h" // Better debug macros
+#include "AliFMD.h"            // ALIFMD_H
+#include "AliFMDDigit.h"       // ALIFMDDIGIT_H
+#include "AliFMDSDigit.h"      // ALIFMDSDIGIT_H
+#include "AliFMDHit.h"         // ALIFMDHIT_H
+#include "AliFMDGeometry.h"    // ALIFMDGEOMETRY_H
+#include "AliFMDDetector.h"    // ALIFMDDETECTOR_H
+#include "AliFMDRing.h"                // ALIFMDRING_H
+#include "AliFMDDigitizer.h"   // ALIFMDDIGITIZER_H
+#include "AliFMDHitDigitizer.h"        // ALIFMDSDIGITIZER_H
+// #define USE_SSDIGITIZER 
+//#ifdef USE_SSDIGITIZER
+//# include "AliFMDSSDigitizer.h"      // ALIFMDSDIGITIZER_H
+//#endif
+// #include "AliFMDGeometryBuilder.h"
+#include "AliFMDRawWriter.h"   // ALIFMDRAWWRITER_H
+#include "AliFMDRawReader.h"   // ALIFMDRAWREADER_H
+#include "AliTrackReference.h" 
+#include "AliFMDStripIndex.h"
+#include "AliFMDParameters.h"
+#include "AliFMDReconstructor.h"
+
+//____________________________________________________________________
 ClassImp(AliFMD)
-//_____________________________________________________________________________
-AliFMD::AliFMD(): AliDetector()
+#if 0
+  ; // This is to keep Emacs from indenting the next line 
+#endif 
+
+//____________________________________________________________________
+AliFMD::AliFMD()
+  : AliDetector(),
+    fSDigits(0), 
+    fNsdigits(0),
+    fDetailed(kTRUE),
+    fUseOld(kFALSE),
+    fUseAssembly(kTRUE),
+    fBad(0) 
 {
   //
   // Default constructor for class AliFMD
   //
-  fIshunt   = 0;
+  AliFMDDebug(10, ("\tDefault CTOR"));
+  fHits        = 0;
+  fDigits      = 0;
+  fIshunt      = 0;
+  fBad         = new TClonesArray("AliFMDHit");
 }
-//_____________________________________________________________________________
+
+//____________________________________________________________________
 AliFMD::AliFMD(const char *name, const char *title)
-       : AliDetector(name,title)
+  : AliDetector (name, title),
+    fSDigits(0),
+    fNsdigits(0),
+    fDetailed(kTRUE),
+    fUseOld(kFALSE),
+    fUseAssembly(kFALSE),
+    fBad(0)
 {
   //
   // Standard constructor for Forward Multiplicity Detector
   //
-  //
+  AliFMDDebug(10, ("\tStandard CTOR"));
+  fBad         = new TClonesArray("AliFMDHit");
+  
   // Initialise Hit array
-  fHits   = new TClonesArray("AliFMDhit",  405);
+  HitsArray();
+  gAlice->GetMCApp()->AddHitList(fHits);
+
+  // (S)Digits for the detectors disk
+  DigitsArray();
+  SDigitsArray();
   
-  fIshunt     =  0;
+  // CHC: What is this?
+  fIshunt = 0;
+  //PH  SetMarkerColor(kRed);
+  //PH  SetLineColor(kYellow);
 }
-//_____________________________________________________________________________
-void AliFMD::AddHit(Int_t track, Int_t *vol, Float_t *hits)
+
+//____________________________________________________________________
+AliFMD::~AliFMD ()
 {
-  //
-  // Add a FMD hit
-  //
-  TClonesArray &lhits = *fHits;
-  new(lhits[fNhits++]) AliFMDhit(fIshunt,track,vol,hits);
+  // Destructor for base class AliFMD
+  if (fHits) {
+    fHits->Delete();
+    delete fHits;
+    fHits = 0;
+  }
+  if (fDigits) {
+    fDigits->Delete();
+    delete fDigits;
+    fDigits = 0;
+  }
+  if (fSDigits) {
+    fSDigits->Delete();
+    delete fSDigits;
+    fSDigits = 0;
+  }
+  if (fBad) {
+    fBad->Delete();
+    delete fBad;
+    fBad = 0;
+  }
 }
-//_____________________________________________________________________________
-void AliFMD::BuildGeometry()
+
+
+//====================================================================
+//
+// GEometry ANd Traking
+//
+//____________________________________________________________________
+void 
+AliFMD::CreateGeometry()
 {
   //
-  // Build simple ROOT TNode geometry for event display
+  // Create the geometry of Forward Multiplicity Detector.  The actual
+  // construction of the geometry is delegated to the class
+  // AliFMDGeometryBuilder, invoked by the singleton manager
+  // AliFMDGeometry. 
   //
-  TNode *Node, *Top;
-  const int kColorFMD  = 7;
-  //
-  Top=gAlice->GetGeometry()->GetNode("alice");
+  AliFMDGeometry*  fmd = AliFMDGeometry::Instance();
+  fmd->SetDetailed(fDetailed);
+  fmd->UseAssembly(fUseAssembly);
+  fmd->Build();
+}    
 
-  // FMD define the different volumes
+//____________________________________________________________________
+void AliFMD::CreateMaterials() 
+{
+  // Define the materials and tracking mediums needed by the FMD
+  // simulation.   These mediums are made by sending the messages
+  // AliMaterial, AliMixture, and AliMedium to the passed AliModule
+  // object module.   The defined mediums are 
+  // 
+  //   FMD Si$         Silicon (active medium in sensors)
+  //   FMD C$          Carbon fibre (support cone for FMD3 and vacuum pipe)
+  //   FMD Al$         Aluminium (honeycomb support plates)
+  //   FMD PCB$        Printed Circuit Board (FEE board with VA1_3)
+  //   FMD Chip$       Electronics chips (currently not used)
+  //   FMD Air$        Air (Air in the FMD)
+  //   FMD Plastic$    Plastic (Support legs for the hybrid cards)
+  //
+  // The geometry builder should really be the one that creates the
+  // materials, but the architecture of AliROOT makes that design
+  // akward.  What should happen, was that the AliFMDGeometryBuilder
+  // made the mediums, and that this class retrives pointers from the
+  // TGeoManager, and registers the mediums here.  Alas, it's not
+  // really that easy. 
+  //
+  AliFMDDebug(10, ("\tCreating materials"));
+  // Get pointer to geometry singleton object. 
+  AliFMDGeometry* geometry = AliFMDGeometry::Instance();
+  geometry->Init();
+#if 0
+  if (gGeoManager && gGeoManager->GetMedium("FMD Si$")) {
+    // We need to figure out the some stuff about the geometry
+    fmd->ExtractGeomInfo();
+    return;
+  }
+#endif  
+  Int_t    id;
+  Double_t a                = 0;
+  Double_t z                = 0;
+  Double_t density          = 0;
+  Double_t radiationLength  = 0;
+  Double_t absorbtionLength = 999;
+  Int_t    fieldType        = ((AliMagF*)TGeoGlobalMagField::Instance()->GetField())->Integ();     // Field type 
+  Double_t maxField         = ((AliMagF*)TGeoGlobalMagField::Instance()->GetField())->Max();     // Field max.
+  Double_t maxBending       = 0;     // Max Angle
+  Double_t maxStepSize      = 0.001; // Max step size 
+  Double_t maxEnergyLoss    = 1;     // Max Delta E
+  Double_t precision        = 0.001; // Precision
+  Double_t minStepSize      = 0.001; // Minimum step size 
+  // Silicon 
+  a                = 28.0855;
+  z                = 14.;
+  density          = geometry->GetSiDensity();
+  radiationLength  = 9.36;
+  maxBending       = 1;
+  maxStepSize      = .001;
+  precision        = .001;
+  minStepSize      = .001;
+  id               = kSiId;
+  AliMaterial(id, "Si$", a, z, density, radiationLength, absorbtionLength);
+  AliMedium(kSiId, "Si$", id,1,fieldType,maxField,maxBending,
+           maxStepSize,maxEnergyLoss,precision,minStepSize);
   
-  new TTUBE("S_FMD1","FMD sensitive volume 1","void",4.5,10.5,3);
-  Top->cd();
-  Node = new TNode("FMD1","FMD1","S_FMD1",0,0,86.5,"");
-  Node->SetLineColor(kColorFMD);
-  fNodes->Add(Node);
+
+  // Carbon 
+  a                = 12.011;
+  z                = 6.;
+  density          = 2.265;
+  radiationLength  = 18.8;
+  maxBending       = 10;
+  maxStepSize      = .01;
+  precision        = .003;
+  minStepSize      = .003;
+  id               = kCarbonId;
+  AliMaterial(id, "Carbon$", a, z, density, radiationLength, absorbtionLength);
+  AliMedium(kCarbonId, "Carbon$", id,0,fieldType,maxField,maxBending,
+                   maxStepSize,maxEnergyLoss,precision,minStepSize);
+
+  // Aluminum
+  a                = 26.981539;
+  z                = 13.;
+  density          = 2.7;
+  radiationLength  = 8.9;
+  id               = kAlId;
+  AliMaterial(id, "Aluminum$",a,z, density, radiationLength, absorbtionLength);
+  AliMedium(kAlId, "Aluminum$", id, 0, fieldType, maxField, maxBending,
+           maxStepSize, maxEnergyLoss, precision, minStepSize);
   
-  new TTUBE("S_FMD2","FMD sensitive volume 2","void",4.5,10.5,3);
-  Top->cd();
-  Node = new TNode("FMD2","FMD2","S_FMD2",0,0,-86.5,"");
-  Node->SetLineColor(kColorFMD);
-  fNodes->Add(Node);
   
-  new TTUBE("S_FMD3","FMD sensitive volume 3","void",8,14,3);
-  Top->cd();
-  Node = new TNode("FMD3","FMD3","S_FMD3",0,0,71.2,"");
-  Node->SetLineColor(kColorFMD);
-  fNodes->Add(Node);
+  // Copper 
+  a                = 63.546;
+  z                = 29;
+  density          =  8.96;
+  radiationLength  =  1.43;
+  id               = kCopperId;
+  AliMaterial(id, "Copper$", 
+                     a, z, density, radiationLength, absorbtionLength);
+  AliMedium(kCopperId, "Copper$", id, 0, fieldType, maxField, maxBending,
+           maxStepSize, maxEnergyLoss, precision, minStepSize);
   
-  new TTUBE("S_FMD4","FMD sensitive volume 4","void",8,14,3);
-  Top->cd();
-  Node = new TNode("FMD4","FMD4","S_FMD4",0,0,-71.2,"");
-  fNodes->Add(Node);
-  Node->SetLineColor(kColorFMD);
+
+  // Silicon chip 
+  {
+    Float_t as[] = { 12.0107,      14.0067,      15.9994,
+                     1.00794,     28.0855,     107.8682 };
+    Float_t zs[] = {  6.,           7.,           8.,
+                     1.,          14.,          47. };
+    Float_t ws[] = {  0.039730642,  0.001396798,  0.01169634,
+                     0.004367771,  0.844665,     0.09814344903 };
+    density          = 2.36436;
+    maxBending       = 10;
+    maxStepSize      = .01;
+    precision        = .003;
+    minStepSize      = .003;
+    id               = kSiChipId;
+    AliMixture(id, "Si Chip$", as, zs, density, 6, ws);
+    AliMedium(kSiChipId, "Si Chip$",  id, 0, fieldType, maxField, maxBending, 
+             maxStepSize, maxEnergyLoss, precision, minStepSize);
+  }
   
-  new TTUBE("S_FMD5","FMD sensitive volume 5","void",8,17.5,3);
-  Top->cd();
-  Node = new TNode("FMD5","FMD5","S_FMD5",0,0,44,"");
-  Node->SetLineColor(kColorFMD);
-  fNodes->Add(Node);
+  // Kaption
+  {
+    Float_t as[] = { 1.00794,  12.0107,  14.010,   15.9994};
+    Float_t zs[] = { 1.,        6.,       7.,       8.};
+    Float_t ws[] = { 0.026362,  0.69113,  0.07327,  0.209235};
+    density          = 1.42;
+    maxBending       = 1;
+    maxStepSize      = .001;
+    precision        = .001;
+    minStepSize      = .001;
+    id               = kKaptonId;
+    AliMixture(id, "Kaption$", as, zs, density, 4, ws);
+    AliMedium(kKaptonId, "Kaption$", id,0,fieldType,maxField,maxBending,
+             maxStepSize,maxEnergyLoss,precision,minStepSize);
+  }
+
+  // Air
+  {
+    Float_t as[] = { 12.0107, 14.0067,   15.9994,  39.948 };
+    Float_t zs[] = {  6.,      7.,       8.,       18. };
+    Float_t ws[] = { 0.000124, 0.755267, 0.231781, 0.012827 }; 
+    density      = .00120479;
+    maxBending   = 1;
+    maxStepSize  = .001;
+    precision    = .001;
+    minStepSize  = .001;
+    id           = kAirId;
+    AliMixture(id, "Air$", as, zs, density, 4, ws);
+    AliMedium(kAirId, "Air$", id,0,fieldType,maxField,maxBending,
+             maxStepSize,maxEnergyLoss,precision,minStepSize);
+  }
   
-  new TTUBE("S_FMD6","FMD sensitive volume 6","void",8,17.5,3);
-  Top->cd();
-  Node = new TNode("FMD6","FMD6","S_FMD6",0,0,-44,"");
-  Node->SetLineColor(kColorFMD);
-  fNodes->Add(Node);
+  // PCB
+  {
+    Float_t zs[] = { 14.,         20.,         13.,         12.,
+                     5.,         22.,         11.,         19.,
+                    26.,          9.,          8.,          6.,
+                     7.,          1.};
+    Float_t as[] = { 28.0855,     40.078,      26.981538,   24.305, 
+                    10.811,      47.867,      22.98977,    39.0983,
+                    55.845,      18.9984,     15.9994,     12.0107,
+                    14.0067,      1.00794};
+    Float_t ws[] = {  0.15144894,  0.08147477,  0.04128158,  0.00904554, 
+                     0.01397570,  0.00287685,  0.00445114,  0.00498089,
+                     0.00209828,  0.00420000,  0.36043788,  0.27529426,
+                     0.01415852,  0.03427566};
+    density      = 1.8;
+    maxBending   = 1;
+    maxStepSize  = .001;
+    precision    = .001;
+    minStepSize  = .001;
+    id           = kPcbId;
+    AliMixture(id, "PCB$", as, zs, density, 14, ws);
+    AliMedium(kPcbId, "PCB$", id,0,fieldType,maxField,maxBending,
+             maxStepSize,maxEnergyLoss,precision,minStepSize);
+  }
   
-  new TTUBE("S_FMD7","FMD sensitive volume 7","void",4.2,13,3);
-  Top->cd();
-  Node = new TNode("FMD7","FMD7","S_FMD7",0,0,-231,"");
-  Node->SetLineColor(kColorFMD);
-  fNodes->Add(Node);
+  // Stainless steel
+  {
+    Float_t as[] = { 55.847, 51.9961, 58.6934, 28.0855 };
+    Float_t zs[] = { 26.,    24.,     28.,     14.     };
+    Float_t ws[] = { .715,   .18,     .1,      .005    };
+    density      = 7.88;
+    id           = kSteelId;
+    AliMixture(id, "Steel$", as, zs, density, 4, ws);
+    AliMedium(kSteelId, "Steel$", id, 0, fieldType, maxField, maxBending, 
+             maxStepSize, maxEnergyLoss, precision, minStepSize);
+  }
+  // Plastic 
+  {
+    Float_t as[] = { 1.01, 12.01 };
+    Float_t zs[] = { 1.,   6.    };
+    Float_t ws[] = { 1.,   1.    };
+    density      = 1.03;
+    maxBending   = 10;
+    maxStepSize  = .01;
+    precision    = .003;
+    minStepSize  = .003;
+    id           = kPlasticId;
+    AliMixture(id, "Plastic$", as, zs, density, -2, ws);
+    AliMedium(kPlasticId, "Plastic$", id,0,fieldType,maxField,maxBending,
+             maxStepSize,maxEnergyLoss,precision,minStepSize);
+  }
+
 }
-//_____________________________________________________________________________
-Int_t AliFMD::DistancetoPrimitive(Int_t , Int_t )
+
+//____________________________________________________________________
+void  
+AliFMD::Init()
+{
+  // Initialize the detector 
+  // 
+  AliFMDDebug(1, ("Initialising FMD detector object"));
+  TVirtualMC*      mc     = TVirtualMC::GetMC();
+  AliFMDGeometry*  fmd    = AliFMDGeometry::Instance();
+  const TArrayI&   actGeo = fmd->ActiveIds();
+  TArrayI          actVmc(actGeo.fN);
+  for (Int_t i = 0; i < actGeo.fN; i++) {
+    TGeoVolume *sens = gGeoManager->GetVolume(actGeo[i]);
+    if (!sens) {
+      AliError(Form("No TGeo volume for sensitive volume ID=%d",actGeo[i]));
+      continue;
+    }   
+    actVmc[i] = mc->VolId(sens->GetName());
+    AliFMDDebug(1, ("Active vol id # %d: %d changed to %d", 
+                   i, actGeo[i], actVmc[i]));
+  }
+  fmd->SetActive(actVmc.fArray, actVmc.fN);
+  // fmd->InitTransformations();
+}
+
+//____________________________________________________________________
+void
+AliFMD::FinishEvent()
 {
+  // Called at the end of the an event in simulations.  If the debug
+  // level is high enough, then the `bad' hits are printed.
+  // 
+  if (AliLog::GetDebugLevel("FMD", "AliFMD") < 10) return;
+  if (fBad && fBad->GetEntries() > 0) {
+    AliWarning((Form("EndEvent", "got %d 'bad' hits", fBad->GetEntries())));
+    TIter next(fBad);
+    AliFMDHit* hit;
+    while ((hit = static_cast<AliFMDHit*>(next()))) hit->Print("D");
+    fBad->Clear();
+  }
+}
+
+
+
+//====================================================================
+//
+// Hit and Digit managment 
+//
+//____________________________________________________________________
+void 
+AliFMD::MakeBranch(Option_t * option)
+{
+  // Create Tree branches for the FMD.
   //
-  // Calculate the distance from the mouse to the FMD on the screen
-  // Dummy routine
+  // Options:
   //
-  return 9999;
+  //    H          Make a branch of TClonesArray of AliFMDHit's
+  //    D          Make a branch of TClonesArray of AliFMDDigit's
+  //    S          Make a branch of TClonesArray of AliFMDSDigit's
+  // 
+  const Int_t kBufferSize = 16000;
+  TString branchname(GetName());
+  TString opt(option);
+  
+  if (opt.Contains("H", TString::kIgnoreCase)) {
+    HitsArray();
+    AliDetector::MakeBranch(option); 
+  }
+  if (opt.Contains("D", TString::kIgnoreCase)) { 
+    DigitsArray();
+    MakeBranchInTree(fLoader->TreeD(), branchname.Data(),
+                    &fDigits, kBufferSize, 0);
+  }
+  if (opt.Contains("S", TString::kIgnoreCase)) { 
+    SDigitsArray();
+    MakeBranchInTree(fLoader->TreeS(), branchname.Data(),
+                    &fSDigits, kBufferSize, 0);
+  }
 }
-//_____________________________________________________________________________
-void AliFMD::StepManager()
+
+//____________________________________________________________________
+void 
+AliFMD::SetTreeAddress()
 {
+  // Set branch address for the Hits, Digits, and SDigits Tree.
+  if (fLoader->TreeH()) HitsArray();
+  AliDetector::SetTreeAddress();
+
+  TTree *treeD = fLoader->TreeD();
+  if (treeD) {
+    DigitsArray();
+    TBranch* branch = treeD->GetBranch ("FMD");
+    if (branch) branch->SetAddress(&fDigits);
+  }
+
+  TTree *treeS = fLoader->TreeS();
+  if (treeS) {
+    SDigitsArray();
+    TBranch* branch = treeS->GetBranch ("FMD");
+    if (branch) branch->SetAddress(&fSDigits);
+  }
+}
+
+//____________________________________________________________________
+void 
+AliFMD::SetHitsAddressBranch(TBranch *b)
+{
+  // Set the TClonesArray to read hits into. 
+  b->SetAddress(&fHits);
+}
+//____________________________________________________________________
+void 
+AliFMD::SetSDigitsAddressBranch(TBranch *b)
+{
+  // Set the TClonesArray to read hits into. 
+  b->SetAddress(&fSDigits);
+}
+
+//____________________________________________________________________
+void 
+AliFMD::AddHit(Int_t track, Int_t *vol, Float_t *hits) 
+{
+  // Add a hit to the hits tree 
+  // 
+  // The information of the two arrays are decoded as 
+  // 
+  // Parameters
+  //    track               Track #
+  //    ivol[0]  [UShort_t ] Detector # 
+  //    ivol[1]         [Char_t   ] Ring ID 
+  //    ivol[2]         [UShort_t ] Sector #
+  //    ivol[3]         [UShort_t ] Strip # 
+  //    hits[0]         [Float_t  ] Track's X-coordinate at hit 
+  //    hits[1]         [Float_t  ] Track's Y-coordinate at hit
+  //    hits[3]  [Float_t  ] Track's Z-coordinate at hit
+  //    hits[4]  [Float_t  ] X-component of track's momentum            
+  //    hits[5]         [Float_t  ] Y-component of track's momentum             
+  //    hits[6]         [Float_t  ] Z-component of track's momentum            
+  //    hits[7]         [Float_t  ] Energy deposited by track                  
+  //    hits[8]         [Int_t    ] Track's particle Id # 
+  //    hits[9]         [Float_t  ] Time when the track hit
+  // 
+  // 
+  AddHitByFields(track, 
+                UShort_t(vol[0]),  // Detector # 
+                Char_t(vol[1]),    // Ring ID
+                UShort_t(vol[2]),  // Sector # 
+                UShort_t(vol[3]),  // Strip # 
+                hits[0],           // X
+                hits[1],           // Y
+                hits[2],           // Z
+                hits[3],           // Px
+                hits[4],           // Py
+                hits[5],           // Pz
+                hits[6],           // Energy loss 
+                Int_t(hits[7]),    // PDG 
+                hits[8]);          // Time
+}
+
+//____________________________________________________________________
+AliFMDHit*
+AliFMD::AddHitByFields(Int_t    track, 
+                      UShort_t detector, 
+                      Char_t   ring, 
+                      UShort_t sector, 
+                      UShort_t strip, 
+                      Float_t  x, 
+                      Float_t  y, 
+                      Float_t  z,
+                      Float_t  px, 
+                      Float_t  py, 
+                      Float_t  pz,
+                      Float_t  edep,
+                      Int_t    pdg,
+                      Float_t  t, 
+                      Float_t  l, 
+                      Bool_t   stop)
+{
+  // Add a hit to the list
   //
-  // Called for each step in the FMD
+  // Parameters:
+  // 
+  //    track    Track #
+  //    detector  Detector # (1, 2, or 3)                      
+  //    ring     Ring ID ('I' or 'O')
+  //    sector   Sector # (For inner/outer rings: 0-19/0-39)
+  //    strip    Strip # (For inner/outer rings: 0-511/0-255)
+  //    x        Track's X-coordinate at hit
+  //    y        Track's Y-coordinate at hit
+  //    z        Track's Z-coordinate at hit
+  //    px       X-component of track's momentum 
+  //    py       Y-component of track's momentum
+  //    pz       Z-component of track's momentum
+  //    edep     Energy deposited by track
+  //    pdg      Track's particle Id #
+  //    t        Time when the track hit 
+  //    l         Track length through the material. 
+  //    stop      Whether track was stopped or disappeared
+  // 
+  TClonesArray& a = *(HitsArray());
+  // Search through the list of already registered hits, and see if we
+  // find a hit with the same parameters.  If we do, then don't create
+  // a new hit, but rather update the energy deposited in the hit.
+  // This is done, so that a FLUKA based simulation will get the
+  // number of hits right, not just the enerrgy deposition. 
+  AliFMDHit* hit = 0;
+  for (Int_t i = 0; i < fNhits; i++) {
+    if (!a.At(i)) continue;
+    hit = static_cast<AliFMDHit*>(a.At(i));
+    if (hit->Detector() == detector 
+       && hit->Ring() == ring
+       && hit->Sector() == sector 
+       && hit->Strip() == strip
+       && hit->Track() == track) {
+      AliFMDDebug(1, ("already had a hit in FMD%d%c[%2d,%3d] for track # %d,"
+                      " adding energy (%f) to that hit (%f) -> %f", 
+                      detector, ring, sector, strip, track, edep, hit->Edep(),
+                      hit->Edep() + edep));
+      hit->SetEdep(hit->Edep() + edep);
+      return hit;
+    }
+  }
+  // If hit wasn't already registered, do so know. 
+  hit = new (a[fNhits]) AliFMDHit(fIshunt, track, detector, ring, sector, 
+                                 strip, x, y, z, px, py, pz, edep, pdg, t, 
+                                 l, stop);
+  // gMC->AddTrackReference(track, 12);
+  fNhits++;
+  
+  //Reference track
+
+  AliMC *mcApplication = (AliMC*)gAlice->GetMCApp();
+  
+  AliTrackReference* trackRef = AddTrackReference(mcApplication->GetCurrentTrackNumber(), AliTrackReference::kFMD); 
+  UInt_t stripId = AliFMDStripIndex::Pack(detector,ring,sector,strip);
+  trackRef->SetUserId(stripId);
+  
+  
+  
+  return hit;
+}
+
+//____________________________________________________________________
+void 
+AliFMD::AddDigit(Int_t* digits, Int_t*)
+{
+  // Add a digit to the Digit tree 
+  // 
+  // Paramters 
   //
+  //    digits[0]  [UShort_t] Detector #
+  //    digits[1]  [Char_t]   Ring ID
+  //    digits[2]  [UShort_t] Sector #
+  //    digits[3]  [UShort_t] Strip #
+  //    digits[4]  [UShort_t] ADC Count 
+  //    digits[5]  [Short_t]  ADC Count, -1 if not used
+  //    digits[6]  [Short_t]  ADC Count, -1 if not used 
+  // 
+  AddDigitByFields(UShort_t(digits[0]),  // Detector #
+                  Char_t(digits[1]),    // Ring ID
+                  UShort_t(digits[2]),  // Sector #
+                  UShort_t(digits[3]),  // Strip #
+                  UShort_t(digits[4]),  // ADC Count1 
+                  Short_t(digits[5]),   // ADC Count2 
+                  Short_t(digits[6]),   // ADC Count3 
+                  Short_t(digits[7])); 
+}
+
+//____________________________________________________________________
+void 
+AliFMD::AddDigitByFields(UShort_t       detector, 
+                        Char_t         ring, 
+                        UShort_t       sector, 
+                        UShort_t       strip, 
+                        UShort_t       count1, 
+                        Short_t        count2,
+                        Short_t        count3, 
+                        Short_t        count4,
+                        const TArrayI& refs)
+{
+  // add a real digit - as coming from data
+  // 
+  // Parameters 
+  //
+  //    detector  Detector # (1, 2, or 3)                      
+  //    ring     Ring ID ('I' or 'O')
+  //    sector   Sector # (For inner/outer rings: 0-19/0-39)
+  //    strip    Strip # (For inner/outer rings: 0-511/0-255)
+  //    count1    ADC count (a 10-bit word)
+  //    count2    ADC count (a 10-bit word), or -1 if not used
+  //    count3    ADC count (a 10-bit word), or -1 if not used
+  TClonesArray& a = *(DigitsArray());
   
-  Float_t       hits[3];
-  Int_t         i,copy,vol[1];
-  TClonesArray &lhits = *fHits;
-  TLorentzVector p;
+  new (a[fNdigits++]) 
+    AliFMDDigit(detector, ring, sector, strip, 
+               count1, count2, count3, count4, refs);
+  AliFMDDebug(15, ("Adding digit # %5d/%5d for FMD%d%c[%2d,%3d]"
+                  "=(%d,%d,%d,%d) with %d tracks",
+                  fNdigits-1, a.GetEntriesFast(),
+                  detector, ring, sector, strip, 
+                  count1, count2, count3, count4, refs.fN));
   
-  gMC->CurrentVolID(copy);
-  vol[0] = copy;
-  gMC->TrackPosition(p);
-  for(i=0;i<3;++i) hits[i]=p[i];
-  new(lhits[fNhits++]) AliFMDhit(fIshunt,gAlice->CurrentTrack(),vol,hits);
 }
 
-//___________________________________________
-void AliFMD::Init()
+//____________________________________________________________________
+void 
+AliFMD::AddSDigit(Int_t* digits)
 {
+  // Add a digit to the SDigit tree 
+  // 
+  // Paramters 
   //
-  // Initialis the FMD after it has been built
-  Int_t i;
+  //    digits[0]  [UShort_t] Detector #
+  //    digits[1]  [Char_t]   Ring ID
+  //    digits[2]  [UShort_t] Sector #
+  //    digits[3]  [UShort_t] Strip #
+  //    digits[4]  [Float_t]  Total energy deposited 
+  //    digits[5]  [UShort_t] ADC Count 
+  //    digits[6]  [Short_t]  ADC Count, -1 if not used
+  //    digits[7]  [Short_t]  ADC Count, -1 if not used 
+  // 
+  AddSDigitByFields(UShort_t(digits[0]),   // Detector #
+                   Char_t(digits[1]),     // Ring ID
+                   UShort_t(digits[2]),   // Sector #
+                   UShort_t(digits[3]),   // Strip #
+                   Float_t(digits[4]),    // Edep
+                   UShort_t(digits[5]),   // ADC Count1 
+                   Short_t(digits[6]),    // ADC Count2 
+                   Short_t(digits[7]),    // ADC Count3 
+                   Short_t(digits[8]),    // ADC Count4
+                   UShort_t(digits[9]),   // N particles
+                   UShort_t(digits[10])); // N primaries
+}
+
+//____________________________________________________________________
+void 
+AliFMD::AddSDigitByFields(UShort_t       detector, 
+                         Char_t         ring, 
+                         UShort_t       sector, 
+                         UShort_t       strip, 
+                         Float_t        edep,
+                         UShort_t       count1, 
+                         Short_t        count2,
+                         Short_t        count3, 
+                         Short_t        count4, 
+                         UShort_t       ntot, 
+                         UShort_t       nprim,
+                         const TArrayI& refs)
+{
+  // add a summable digit
+  // 
+  // Parameters 
   //
-  printf("\n");
-  for(i=0;i<35;i++) printf("*");
-  printf(" FMD_INIT ");
-  for(i=0;i<35;i++) printf("*");
-  printf("\n");
+  //    detector  Detector # (1, 2, or 3)                      
+  //    ring     Ring ID ('I' or 'O')
+  //    sector   Sector # (For inner/outer rings: 0-19/0-39)
+  //    strip    Strip # (For inner/outer rings: 0-511/0-255)
+  //    edep      Total energy deposited
+  //    count1    ADC count (a 10-bit word)
+  //    count2    ADC count (a 10-bit word), or -1 if not used
+  //    count3    ADC count (a 10-bit word), or -1 if not used
   //
-  // Here the FMD initialisation code (if any!)
-  for(i=0;i<80;i++) printf("*");
-  printf("\n");
+  TClonesArray& a = *(SDigitsArray());
+  // AliFMDDebug(0, ("Adding sdigit # %d", fNsdigits));
+  
+  new (a[fNsdigits++]) 
+    AliFMDSDigit(detector, ring, sector, strip, edep, 
+                count1, count2, count3, count4, ntot, nprim, refs);
 }
 
-ClassImp(AliFMDhit)
-//_____________________________________________________________________________
-AliFMDhit::AliFMDhit(Int_t shunt, Int_t track, Int_t *vol, Float_t *hits):
-  AliHit(shunt, track)
+//____________________________________________________________________
+void 
+AliFMD::ResetSDigits()
+{
+  // Reset number of digits and the digits array for this detector. 
+  //
+  fNsdigits   = 0;
+  if (fSDigits) fSDigits->Clear();
+}
+
+
+//____________________________________________________________________
+TClonesArray*
+AliFMD::HitsArray() 
+{
+  // Initialize hit array if not already, and return pointer to it. 
+  if (!fHits) { 
+    fHits = new TClonesArray("AliFMDHit", 1000);
+    fNhits = 0;
+  }
+  return fHits;
+}
+
+//____________________________________________________________________
+TClonesArray*
+AliFMD::DigitsArray() 
+{
+  // Initialize digit array if not already, and return pointer to it. 
+  if (!fDigits) { 
+    fDigits = new TClonesArray("AliFMDDigit", 1000);
+    fNdigits = 0;
+  }
+  return fDigits;
+}
+
+//____________________________________________________________________
+TClonesArray*
+AliFMD::SDigitsArray() 
+{
+  // Initialize digit array if not already, and return pointer to it. 
+  if (!fSDigits) { 
+    fSDigits = new TClonesArray("AliFMDSDigit", 1000);
+    fNsdigits = 0;
+  }
+  return fSDigits;
+}
+
+//====================================================================
+//
+// Digitization 
+//
+//____________________________________________________________________
+void 
+AliFMD::Hits2Digits() 
 {
+  // Create AliFMDDigit's from AliFMDHit's.  This is done by making a
+  // AliFMDDigitizer, and executing that code.
+  // 
+  AliFMDHitDigitizer digitizer(this, AliFMDHitDigitizer::kDigits);
+  digitizer.Init();
+  digitizer.Exec("");
+}
+
+//____________________________________________________________________
+void 
+AliFMD::Hits2SDigits() 
+{
+  // Create AliFMDSDigit's from AliFMDHit's.  This is done by creating
+  // an AliFMDSDigitizer object, and executing it. 
+  // 
+  AliFMDHitDigitizer digitizer(this, AliFMDHitDigitizer::kSDigits);
+  digitizer.Init();
+  digitizer.Exec("");
+}
+
+  
+//____________________________________________________________________
+AliDigitizer* 
+AliFMD::CreateDigitizer(AliRunDigitizer* manager) const
+{
+  // Create a digitizer object 
+  
+  /* This is what we probably _should_ do */
+  AliFMDBaseDigitizer* digitizer = 0;
+  
+#ifdef USE_SSDIGITIZER
+  digitizer = new AliFMDSSDigitizer(manager);
+#else 
+  /* This is what we actually do, and will work */
+#if 0
+  AliInfo("SDigit->Digit conversion not really supported, "
+         "doing Hit->Digit conversion instead");
+#endif
+  digitizer = new AliFMDDigitizer(manager);
+#endif
+  return digitizer;
+}
+
+//====================================================================
+//
+// Raw data simulation 
+//
+//__________________________________________________________________
+void 
+AliFMD::Digits2Raw() 
+{
+  // Turn digits into raw data. 
+  // 
+  // This uses the class AliFMDRawWriter to do the job.   Please refer
+  // to that class for more information. 
+  AliFMDRawWriter writer(this);
+  writer.Exec();
+}
+
+//====================================================================
+//
+// Raw data reading 
+//
+//__________________________________________________________________
+Bool_t
+AliFMD::Raw2SDigits(AliRawReader* reader) 
+{
+  // Turn digits into raw data. 
+  // 
+  // This uses the class AliFMDRawWriter to do the job.   Please refer
+  // to that class for more information. 
+  AliFMDParameters::Instance()->Init();
+  MakeTree("S");
+  MakeBranch("S");
+  
+  TClonesArray*       sdigits = SDigits();
+  AliFMDReconstructor rec;
+  
+  // The two boolean arguments
+  //   Make sdigits instead of digits 
+  //   Subtract the pedestal off the signal
+  rec.Digitize(reader, sdigits);
+  // 
+  // Bool_t ret = fmdReader.ReadAdcs(sdigits, kTRUE, kTRUE);
+  // sdigits->ls();
+  UShort_t ns = sdigits->GetEntriesFast();
+  for (UShort_t i = 0; i < ns; i++) 
+    sdigits->At(i)->Print("pl");
+  
+  AliFMDDebug(1, ("Got a total of %d SDigits", ns));
+
+  fLoader->TreeS()->Fill();
+  ResetSDigits();
+  fLoader->WriteSDigits("OVERWRITE");
+
+  return kTRUE;
+}
+
+
+//====================================================================
+//
+// Utility 
+//
+//__________________________________________________________________
+void 
+AliFMD::Browse(TBrowser* b) 
+{
+  // Browse this object. 
   //
-  // Add a FMD hit
+  AliFMDDebug(30, ("\tBrowsing the FMD"));
+  AliDetector::Browse(b);
+  b->Add(AliFMDGeometry::Instance());
+}
+
+//____________________________________________________________________ 
+void
+AliFMD::AddAlignableVolumes() const
+{
   //
-  fVolume = vol[0];
-  fX=hits[0];
-  fY=hits[1];
-  fZ=hits[2];
+  // Create entries for alignable volumes associating the symbolic volume
+  // name with the corresponding volume path. Needs to be syncronized with
+  // eventual changes in the geometry.
+  // 
+  // This code was made by Raffaele Grosso <rgrosso@mail.cern.ch>.  I
+  // (cholm) will probably want to change it.   For one, I think it
+  // should be the job of the geometry manager to deal with this. 
+  AliInfo("Add FMD alignable volumes");
+  AliFMDGeometry::Instance()->SetAlignableVolumes();
+#if 0  
+  for(size_t f = 1; f <= 3; f++){ // Detector 1,2,3
+    for(size_t tb =  0; tb <2 ; tb++){ // Top/Bottom 
+      char     stb = tb == 0 ? 'T' : 'B';
+      unsigned min = tb == 0 ? 0   : 5;
+
+      TString halfVol(Form("/ALIC_1/F%dM%c_%d", f, stb, f));
+      TString halfSym(halfVol);
+      if(!gGeoManager->SetAlignableEntry(halfSym.Data(),halfVol.Data()))
+       AliFatal(Form("Alignable entry %s not created. "
+                     "Volume path %s not valid", 
+                     halfSym.Data(),halfVol.Data()));
+      for(size_t io = 0; io < 2; io++){ // inner, outer 
+       if (f==1 && io==1) continue; // Only one ring in FMD1 
+       if(tb == 1 && io==1) min=10;
+       char     sio = (io == 0 ? 'I' : 'O');
+       unsigned nio = (io == 0 ? 3   : 9);
+       unsigned max = (io == 0 ? 5   : 10) + min;
+       
+       for(size_t i = min; i < max; i++) { // Modules
+         TString modVol(Form("%s/F%c%cV_7%d/F%cSE_%d", halfVol.Data(), 
+                             sio, stb, nio, sio, i));
+         TString modSym(modVol);
+         if(!gGeoManager->SetAlignableEntry(modSym.Data(),modVol.Data()))
+           AliFatal(Form("Alignable entry %s not created. "
+                         "Volume path %s not valid", 
+                         modSym.Data(), modVol.Data()));
+       }
+      }
+    }
+  }
+#endif
 }
+//___________________________________________________________________
+//
+// EOF
+//