]> git.uio.no Git - u/mrichter/AliRoot.git/blobdiff - MUON/AliMUONv1.cxx
Avoid ambiguities in function overloading for new Virtual MC
[u/mrichter/AliRoot.git] / MUON / AliMUONv1.cxx
index f7059904f0c6c61d8a526637e1500e1cf58ef149..33c8f036d64e975e544e08b70bf149b6c67855a1 100644 (file)
  * 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 purpeateose. It is          *
+ * about the suitability of this software for any purpeateose. It is      *
  * provided "as is" without express or implied warranty.                  *
  **************************************************************************/
 
 /*
 $Log$
+Revision 1.33  2002/07/23 10:02:46  morsch
+All volume names start with "S".
+
+Revision 1.32  2002/05/02 12:51:10  morsch
+For G4: gMC->VolId(...) replaced by gAlice->GetModule(...).
+
+Revision 1.31  2002/03/13 07:55:04  jchudoba
+Correction of the errourness last commit.
+
+Revision 1.29  2001/06/21 14:54:37  morsch
+Put volumes of station 3 into DIPO if present. (A. de Falco)
+
+Revision 1.28  2001/05/16 14:57:17  alibrary
+New files for folders and Stack
+
+Revision 1.27  2001/04/06 11:24:43  morsch
+Dependency on implementations of AliSegmentation and AliMUONResponse moved to AliMUONFactory class.
+Static method Build() builds the MUON system out of chambers, segmentation and response.
+
+Revision 1.26  2001/03/17 10:07:20  morsch
+Correct inconsistent variable name / method name / comments.
+
+Revision 1.25  2001/03/16 15:32:06  morsch
+Corrections of overlap with beam shield and dipole (A. de Falco)
+
+Revision 1.24  2001/03/14 17:22:15  pcrochet
+Geometry of the trigger chambers : a vertical gap of has been introduced around x=0 according fig.3.27 of the TDR (P.Dupieux)
+
+Revision 1.23  2001/01/18 15:23:49  egangler
+Bug correction in StepManager :
+Now the systematic offset with angle is cured
+
+Revision 1.22  2001/01/17 21:01:21  hristov
+Unused variable removed
+
+Revision 1.21  2000/12/20 13:00:22  egangler
+
+Added charge correlation between cathods.
+In Config_slat.C, use
+ MUON->Chamber(chamber-1).SetChargeCorrel(0.11); to set the RMS of
+ q1/q2 to 11 % (number from Alberto)
+ This is stored in AliMUONChamber fChargeCorrel member.
+ At generation time, when a tracks enters the volume,
+ AliMUONv1::StepManager calls
+ AliMUONChamber::ChargeCorrelationInit() to set the current value of
+ fCurrentCorrel which is then used at Disintegration level to scale
+ appropriately the PadHit charges.
+
+Revision 1.20  2000/12/04 17:48:23  gosset
+Modifications for stations 1 et 2 mainly:
+* station 1 with 4 mm gas gap and smaller cathode segmentation...
+* stations 1 and 2 with "grey" frame crosses
+* mean noise at 1.5 ADC channel
+* Ar-CO2 gas (80%+20%)
+
+Revision 1.19  2000/12/02 17:15:46  morsch
+Correction of dead zones in inner regions of stations 3-5
+Correction of length of slats 3 and 9 of station 4.
+
+Revision 1.17  2000/11/24 12:57:10  morsch
+New version of geometry for stations 3-5 "Slats" (A. de Falco)
+ - sensitive region at station 3 inner radius
+ - improved volume tree structure
+
+Revision 1.16  2000/11/08 13:01:40  morsch
+Chamber half-planes of stations 3-5 at different z-positions.
+
+Revision 1.15  2000/11/06 11:39:02  morsch
+Bug in StepManager() corrected.
+
+Revision 1.14  2000/11/06 09:16:50  morsch
+Avoid overlap of slat volumes.
+
+Revision 1.13  2000/10/26 07:33:44  morsch
+Correct x-position of slats in station 5.
+
+Revision 1.12  2000/10/25 19:55:35  morsch
+Switches for each station individually for debug and lego.
+
+Revision 1.11  2000/10/22 16:44:01  morsch
+Update of slat geometry for stations 3,4,5 (A. deFalco)
+
+Revision 1.10  2000/10/12 16:07:04  gosset
+StepManager:
+* SigGenCond only called for tracking chambers,
+  hence no more division by 0,
+  and may use last ALIROOT/dummies.C with exception handling;
+* "10" replaced by "AliMUONConstants::NTrackingCh()".
+
 Revision 1.9  2000/10/06 15:37:22  morsch
 Problems with variable redefinition in for-loop solved.
 Variable names starting with u-case letters changed to l-case.
@@ -82,6 +171,7 @@ Log messages included.
 #include "AliMUONPadHit.h"
 #include "AliMUONConstants.h"
 #include "AliMUONTriggerCircuit.h"
+#include "AliMUONFactory.h"
 
 ClassImp(AliMUONv1)
  
@@ -97,6 +187,7 @@ AliMUONv1::AliMUONv1(const char *name, const char *title)
        : AliMUON(name,title)
 {
 // Constructor
+    AliMUONFactory::Build(this, title);
 }
 
 //___________________________________________
@@ -113,15 +204,25 @@ void AliMUONv1::CreateGeometry()
 //
      Float_t bpar[3];
      Float_t tpar[3];
-     Float_t pgpar[10];
+//      Float_t pgpar[10];
      Float_t zpos1, zpos2, zfpos;
+     // Outer excess and inner recess for mother volume radius
+     // with respect to ROuter and RInner
      Float_t dframep=.001; // Value for station 3 should be 6 ...
-     Float_t dframep1=.001;
-//     Bool_t frames=kTRUE;
-     Bool_t frames=kFALSE;     
+     // Width (RdPhi) of the frame crosses for stations 1 and 2 (cm)
+//      Float_t dframep1=.001;
+     Float_t dframep1 = 11.0;
+//      Bool_t frameCrosses=kFALSE;     
+     Bool_t frameCrosses=kTRUE;     
+     Float_t *dum=0;
      
-     Float_t dframez=0.9;
-     Float_t dr;
+//      Float_t dframez=0.9;
+     // Half of the total thickness of frame crosses (including DAlu)
+     // for each chamber in stations 1 and 2:
+     // 3% of X0 of composite material,
+     // but taken as Aluminium here, with same thickness in number of X0
+     Float_t dframez = 3. * 8.9 / 100;
+//      Float_t dr;
      Float_t dstation;
 
 //
@@ -141,15 +242,20 @@ void AliMUONv1::CreateGeometry()
 //
 //   pointer to the current chamber
 //   pointer to the current chamber
-     Int_t idAlu1=idtmed[1103];
-     Int_t idAlu2=idtmed[1104];
+     Int_t idAlu1=idtmed[1103]; // medium 4
+     Int_t idAlu2=idtmed[1104]; // medium 5
 //     Int_t idAlu1=idtmed[1100];
 //     Int_t idAlu2=idtmed[1100];
-     Int_t idAir=idtmed[1100];
-     Int_t idGas=idtmed[1105];
+     Int_t idAir=idtmed[1100]; // medium 1
+//      Int_t idGas=idtmed[1105]; // medium 6 = Ar-isoC4H10 gas
+     Int_t idGas=idtmed[1108]; // medium 9 = Ar-CO2 gas (80%+20%)
      
 
      AliMUONChamber *iChamber, *iChamber1, *iChamber2;
+     Int_t stations[5] = {1, 1, 1, 1, 1};
+     
+     if (stations[0]) {
+        
 //********************************************************************
 //                            Station 1                             **
 //********************************************************************
@@ -162,90 +268,101 @@ void AliMUONv1::CreateGeometry()
      zpos1=iChamber1->Z(); 
      zpos2=iChamber2->Z();
      dstation = zpos2 - zpos1;
+     // DGas decreased from standard one (0.5)
+     iChamber->SetDGas(0.4); iChamber2->SetDGas(0.4);
+     // DAlu increased from standard one (3% of X0),
+     // because more electronics with smaller pads
+     iChamber->SetDAlu(3.5 * 8.9 / 100.); iChamber2->SetDAlu(3.5 * 8.9 / 100.);
      zfpos=-(iChamber->DGas()+dframez+iChamber->DAlu())/2;
      
 //
 //   Mother volume
-     tpar[0] = iChamber->RInner()-dframep1
-     tpar[1] = (iChamber->ROuter()+dframep1)/TMath::Cos(phi);
-     tpar[2] = dstation/4;
-
-     gMC->Gsvolu("C01M", "TUBE", idAir, tpar, 3);
-     gMC->Gsvolu("C02M", "TUBE", idAir, tpar, 3);
-     gMC->Gspos("C01M", 1, "ALIC", 0., 0., zpos1 , 0, "ONLY");
-     gMC->Gspos("C02M", 1, "ALIC", 0., 0., zpos2 , 0, "ONLY");     
-// Aluminium frames
-// Outer frames
-     pgpar[0] = 360/12/2;
-     pgpar[1] = 360.;
-     pgpar[2] = 12.;
-     pgpar[3] =   2;
-     pgpar[4] = -dframez/2;
-     pgpar[5] = iChamber->ROuter();
-     pgpar[6] = pgpar[5]+dframep1;
-     pgpar[7] = +dframez/2;
-     pgpar[8] = pgpar[5];
-     pgpar[9] = pgpar[6];
-     gMC->Gsvolu("C01O", "PGON", idAlu1, pgpar, 10);
-     gMC->Gsvolu("C02O", "PGON", idAlu1, pgpar, 10);
-     gMC->Gspos("C01O",1,"C01M", 0.,0.,-zfpos,  0,"ONLY");
-     gMC->Gspos("C01O",2,"C01M", 0.,0.,+zfpos,  0,"ONLY");
-     gMC->Gspos("C02O",1,"C02M", 0.,0.,-zfpos,  0,"ONLY");
-     gMC->Gspos("C02O",2,"C02M", 0.,0.,+zfpos,  0,"ONLY");
-//
-// Inner frame
-     tpar[0]= iChamber->RInner()-dframep1;
-     tpar[1]= iChamber->RInner();
-     tpar[2]= dframez/2;
-     gMC->Gsvolu("C01I", "TUBE", idAlu1, tpar, 3);
-     gMC->Gsvolu("C02I", "TUBE", idAlu1, tpar, 3);
-
-     gMC->Gspos("C01I",1,"C01M", 0.,0.,-zfpos,  0,"ONLY");
-     gMC->Gspos("C01I",2,"C01M", 0.,0.,+zfpos,  0,"ONLY");
-     gMC->Gspos("C02I",1,"C02M", 0.,0.,-zfpos,  0,"ONLY");
-     gMC->Gspos("C02I",2,"C02M", 0.,0.,+zfpos,  0,"ONLY");
+     tpar[0] = iChamber->RInner()-dframep; 
+     tpar[1] = (iChamber->ROuter()+dframep)/TMath::Cos(phi);
+     tpar[2] = dstation/5;
+
+     gMC->Gsvolu("S01M", "TUBE", idAir, tpar, 3);
+     gMC->Gsvolu("S02M", "TUBE", idAir, tpar, 3);
+     gMC->Gspos("S01M", 1, "ALIC", 0., 0., zpos1 , 0, "ONLY");
+     gMC->Gspos("S02M", 1, "ALIC", 0., 0., zpos2 , 0, "ONLY");     
+// // Aluminium frames
+// // Outer frames
+//      pgpar[0] = 360/12/2;
+//      pgpar[1] = 360.;
+//      pgpar[2] = 12.;
+//      pgpar[3] =   2;
+//      pgpar[4] = -dframez/2;
+//      pgpar[5] = iChamber->ROuter();
+//      pgpar[6] = pgpar[5]+dframep1;
+//      pgpar[7] = +dframez/2;
+//      pgpar[8] = pgpar[5];
+//      pgpar[9] = pgpar[6];
+//      gMC->Gsvolu("S01O", "PGON", idAlu1, pgpar, 10);
+//      gMC->Gsvolu("S02O", "PGON", idAlu1, pgpar, 10);
+//      gMC->Gspos("S01O",1,"S01M", 0.,0.,-zfpos,  0,"ONLY");
+//      gMC->Gspos("S01O",2,"S01M", 0.,0.,+zfpos,  0,"ONLY");
+//      gMC->Gspos("S02O",1,"S02M", 0.,0.,-zfpos,  0,"ONLY");
+//      gMC->Gspos("S02O",2,"S02M", 0.,0.,+zfpos,  0,"ONLY");
+// //
+// // Inner frame
+//      tpar[0]= iChamber->RInner()-dframep1;
+//      tpar[1]= iChamber->RInner();
+//      tpar[2]= dframez/2;
+//      gMC->Gsvolu("S01I", "TUBE", idAlu1, tpar, 3);
+//      gMC->Gsvolu("S02I", "TUBE", idAlu1, tpar, 3);
+
+//      gMC->Gspos("S01I",1,"S01M", 0.,0.,-zfpos,  0,"ONLY");
+//      gMC->Gspos("S01I",2,"S01M", 0.,0.,+zfpos,  0,"ONLY");
+//      gMC->Gspos("S02I",1,"S02M", 0.,0.,-zfpos,  0,"ONLY");
+//      gMC->Gspos("S02I",2,"S02M", 0.,0.,+zfpos,  0,"ONLY");
 //
 // Frame Crosses
-     if (frames) {
-
-        bpar[0] = (iChamber->ROuter() - iChamber->RInner())/2;
+     if (frameCrosses) {
+         // outside gas
+         // security for inside mother volume
+        bpar[0] = (iChamber->ROuter() - iChamber->RInner())
+          * TMath::Cos(TMath::ASin(dframep1 /
+                                  (iChamber->ROuter() - iChamber->RInner())))
+          / 2.0;
         bpar[1] = dframep1/2;
-        bpar[2] = dframez/2;
-        gMC->Gsvolu("C01B", "BOX", idAlu1, bpar, 3);
-        gMC->Gsvolu("C02B", "BOX", idAlu1, bpar, 3);
+        // total thickness will be (4 * bpar[2]) for each chamber,
+        // which has to be equal to (2 * dframez) - DAlu
+        bpar[2] = (2.0 * dframez - iChamber->DAlu()) / 4.0;
+        gMC->Gsvolu("S01B", "BOX", idAlu1, bpar, 3);
+        gMC->Gsvolu("S02B", "BOX", idAlu1, bpar, 3);
         
-        gMC->Gspos("C01B",1,"C01M", +iChamber->RInner()+bpar[0] , 0,-zfpos, 
+        gMC->Gspos("S01B",1,"S01M", +iChamber->RInner()+bpar[0] , 0,-zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C01B",2,"C01M", -iChamber->RInner()-bpar[0] , 0,-zfpos, 
+        gMC->Gspos("S01B",2,"S01M", -iChamber->RInner()-bpar[0] , 0,-zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C01B",3,"C01M", 0, +iChamber->RInner()+bpar[0] ,-zfpos, 
+        gMC->Gspos("S01B",3,"S01M", 0, +iChamber->RInner()+bpar[0] ,-zfpos, 
                    idrotm[1101],"ONLY");
-        gMC->Gspos("C01B",4,"C01M", 0, -iChamber->RInner()-bpar[0] ,-zfpos, 
+        gMC->Gspos("S01B",4,"S01M", 0, -iChamber->RInner()-bpar[0] ,-zfpos, 
                    idrotm[1101],"ONLY");
-        gMC->Gspos("C01B",5,"C01M", +iChamber->RInner()+bpar[0] , 0,+zfpos, 
+        gMC->Gspos("S01B",5,"S01M", +iChamber->RInner()+bpar[0] , 0,+zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C01B",6,"C01M", -iChamber->RInner()-bpar[0] , 0,+zfpos, 
+        gMC->Gspos("S01B",6,"S01M", -iChamber->RInner()-bpar[0] , 0,+zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C01B",7,"C01M", 0, +iChamber->RInner()+bpar[0] ,+zfpos, 
+        gMC->Gspos("S01B",7,"S01M", 0, +iChamber->RInner()+bpar[0] ,+zfpos, 
                    idrotm[1101],"ONLY");
-        gMC->Gspos("C01B",8,"C01M", 0, -iChamber->RInner()-bpar[0] ,+zfpos, 
+        gMC->Gspos("S01B",8,"S01M", 0, -iChamber->RInner()-bpar[0] ,+zfpos, 
                    idrotm[1101],"ONLY");
         
-        gMC->Gspos("C02B",1,"C02M", +iChamber->RInner()+bpar[0] , 0,-zfpos, 
+        gMC->Gspos("S02B",1,"S02M", +iChamber->RInner()+bpar[0] , 0,-zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C02B",2,"C02M", -iChamber->RInner()-bpar[0] , 0,-zfpos, 
+        gMC->Gspos("S02B",2,"S02M", -iChamber->RInner()-bpar[0] , 0,-zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C02B",3,"C02M", 0, +iChamber->RInner()+bpar[0] ,-zfpos, 
+        gMC->Gspos("S02B",3,"S02M", 0, +iChamber->RInner()+bpar[0] ,-zfpos, 
                    idrotm[1101],"ONLY");
-        gMC->Gspos("C02B",4,"C02M", 0, -iChamber->RInner()-bpar[0] ,-zfpos, 
+        gMC->Gspos("S02B",4,"S02M", 0, -iChamber->RInner()-bpar[0] ,-zfpos, 
                    idrotm[1101],"ONLY");
-        gMC->Gspos("C02B",5,"C02M", +iChamber->RInner()+bpar[0] , 0,+zfpos, 
+        gMC->Gspos("S02B",5,"S02M", +iChamber->RInner()+bpar[0] , 0,+zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C02B",6,"C02M", -iChamber->RInner()-bpar[0] , 0,+zfpos, 
+        gMC->Gspos("S02B",6,"S02M", -iChamber->RInner()-bpar[0] , 0,+zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C02B",7,"C02M", 0, +iChamber->RInner()+bpar[0] ,+zfpos, 
+        gMC->Gspos("S02B",7,"S02M", 0, +iChamber->RInner()+bpar[0] ,+zfpos, 
                    idrotm[1101],"ONLY");
-        gMC->Gspos("C02B",8,"C02M", 0, -iChamber->RInner()-bpar[0] ,+zfpos, 
+        gMC->Gspos("S02B",8,"S02M", 0, -iChamber->RInner()-bpar[0] ,+zfpos, 
                    idrotm[1101],"ONLY");
      }
 //
@@ -253,48 +370,51 @@ void AliMUONv1::CreateGeometry()
      tpar[0]= iChamber->RInner();
      tpar[1]= iChamber->ROuter();
      tpar[2] = (iChamber->DGas()+iChamber->DAlu())/2;
-     gMC->Gsvolu("C01A", "TUBE",  idAlu2, tpar, 3);
-     gMC->Gsvolu("C02A", "TUBE",idAlu2, tpar, 3);
-     gMC->Gspos("C01A", 1, "C01M", 0., 0., 0.,  0, "ONLY");
-     gMC->Gspos("C02A", 1, "C02M", 0., 0., 0.,  0, "ONLY");
+     gMC->Gsvolu("S01A", "TUBE",  idAlu2, tpar, 3);
+     gMC->Gsvolu("S02A", "TUBE",idAlu2, tpar, 3);
+     gMC->Gspos("S01A", 1, "S01M", 0., 0., 0.,  0, "ONLY");
+     gMC->Gspos("S02A", 1, "S02M", 0., 0., 0.,  0, "ONLY");
 //     
 //   Sensitive volumes
      // tpar[2] = iChamber->DGas();
      tpar[2] = iChamber->DGas()/2;
-     gMC->Gsvolu("C01G", "TUBE", idtmed[1108], tpar, 3);
-     gMC->Gsvolu("C02G", "TUBE", idtmed[1108], tpar, 3);
-     gMC->Gspos("C01G", 1, "C01A", 0., 0., 0.,  0, "ONLY");
-     gMC->Gspos("C02G", 1, "C02A", 0., 0., 0.,  0, "ONLY");
+     gMC->Gsvolu("S01G", "TUBE", idGas, tpar, 3);
+     gMC->Gsvolu("S02G", "TUBE", idGas, tpar, 3);
+     gMC->Gspos("S01G", 1, "S01A", 0., 0., 0.,  0, "ONLY");
+     gMC->Gspos("S02G", 1, "S02A", 0., 0., 0.,  0, "ONLY");
 //
-// Frame Crosses to be placed inside gas 
-     if (frames) {
-
-        dr = (iChamber->ROuter() - iChamber->RInner());
-        bpar[0] = TMath::Sqrt(dr*dr-dframep1*dframep1/4)/2;
-        bpar[1] = dframep1/2;
-        bpar[2] = iChamber->DGas()/2;
-        gMC->Gsvolu("C01F", "BOX", idAlu1, bpar, 3);
-        gMC->Gsvolu("C02F", "BOX", idAlu1, bpar, 3);
+// Frame Crosses to be placed inside gas
+     // NONE: chambers are sensitive everywhere
+//      if (frameCrosses) {
+
+//      dr = (iChamber->ROuter() - iChamber->RInner());
+//      bpar[0] = TMath::Sqrt(dr*dr-dframep1*dframep1/4)/2;
+//      bpar[1] = dframep1/2;
+//      bpar[2] = iChamber->DGas()/2;
+//      gMC->Gsvolu("S01F", "BOX", idAlu1, bpar, 3);
+//      gMC->Gsvolu("S02F", "BOX", idAlu1, bpar, 3);
         
-        gMC->Gspos("C01F",1,"C01G", +iChamber->RInner()+bpar[0] , 0, 0, 
-                   idrotm[1100],"ONLY");
-        gMC->Gspos("C01F",2,"C01G", -iChamber->RInner()-bpar[0] , 0, 0, 
-                   idrotm[1100],"ONLY");
-        gMC->Gspos("C01F",3,"C01G", 0, +iChamber->RInner()+bpar[0] , 0, 
-                   idrotm[1101],"ONLY");
-        gMC->Gspos("C01F",4,"C01G", 0, -iChamber->RInner()-bpar[0] , 0, 
-                   idrotm[1101],"ONLY");
+//      gMC->Gspos("S01F",1,"S01G", +iChamber->RInner()+bpar[0] , 0, 0, 
+//                 idrotm[1100],"ONLY");
+//      gMC->Gspos("S01F",2,"S01G", -iChamber->RInner()-bpar[0] , 0, 0, 
+//                 idrotm[1100],"ONLY");
+//      gMC->Gspos("S01F",3,"S01G", 0, +iChamber->RInner()+bpar[0] , 0, 
+//                 idrotm[1101],"ONLY");
+//      gMC->Gspos("S01F",4,"S01G", 0, -iChamber->RInner()-bpar[0] , 0, 
+//                 idrotm[1101],"ONLY");
         
-        gMC->Gspos("C02F",1,"C02G", +iChamber->RInner()+bpar[0] , 0, 0, 
-                   idrotm[1100],"ONLY");
-        gMC->Gspos("C02F",2,"C02G", -iChamber->RInner()-bpar[0] , 0, 0, 
-                   idrotm[1100],"ONLY");
-        gMC->Gspos("C02F",3,"C02G", 0, +iChamber->RInner()+bpar[0] , 0, 
-                   idrotm[1101],"ONLY");
-        gMC->Gspos("C02F",4,"C02G", 0, -iChamber->RInner()-bpar[0] , 0, 
-                   idrotm[1101],"ONLY");
+//      gMC->Gspos("S02F",1,"S02G", +iChamber->RInner()+bpar[0] , 0, 0, 
+//                 idrotm[1100],"ONLY");
+//      gMC->Gspos("S02F",2,"S02G", -iChamber->RInner()-bpar[0] , 0, 0, 
+//                 idrotm[1100],"ONLY");
+//      gMC->Gspos("S02F",3,"S02G", 0, +iChamber->RInner()+bpar[0] , 0, 
+//                 idrotm[1101],"ONLY");
+//      gMC->Gspos("S02F",4,"S02G", 0, -iChamber->RInner()-bpar[0] , 0, 
+//                 idrotm[1101],"ONLY");
+//      }
      }
-
+     if (stations[1]) {
+        
 //********************************************************************
 //                            Station 2                             **
 //********************************************************************
@@ -306,91 +426,98 @@ void AliMUONv1::CreateGeometry()
      zpos1=iChamber1->Z(); 
      zpos2=iChamber2->Z();
      dstation = zpos2 - zpos1;
+     // DGas and DAlu not changed from standard values
      zfpos=-(iChamber->DGas()+dframez+iChamber->DAlu())/2;
      
 //
 //   Mother volume
      tpar[0] = iChamber->RInner()-dframep; 
      tpar[1] = (iChamber->ROuter()+dframep)/TMath::Cos(phi);
-     tpar[2] = dstation/4;
-
-     gMC->Gsvolu("C03M", "TUBE", idAir, tpar, 3);
-     gMC->Gsvolu("C04M", "TUBE", idAir, tpar, 3);
-     gMC->Gspos("C03M", 1, "ALIC", 0., 0., zpos1 , 0, "ONLY");
-     gMC->Gspos("C04M", 1, "ALIC", 0., 0., zpos2 , 0, "ONLY");
-
-// Aluminium frames
-// Outer frames
-     pgpar[0] = 360/12/2;
-     pgpar[1] = 360.;
-     pgpar[2] = 12.;
-     pgpar[3] =   2;
-     pgpar[4] = -dframez/2;
-     pgpar[5] = iChamber->ROuter();
-     pgpar[6] = pgpar[5]+dframep;
-     pgpar[7] = +dframez/2;
-     pgpar[8] = pgpar[5];
-     pgpar[9] = pgpar[6];
-     gMC->Gsvolu("C03O", "PGON", idAlu1, pgpar, 10);
-     gMC->Gsvolu("C04O", "PGON", idAlu1, pgpar, 10);
-     gMC->Gspos("C03O",1,"C03M", 0.,0.,-zfpos,  0,"ONLY");
-     gMC->Gspos("C03O",2,"C03M", 0.,0.,+zfpos,  0,"ONLY");
-     gMC->Gspos("C04O",1,"C04M", 0.,0.,-zfpos,  0,"ONLY");
-     gMC->Gspos("C04O",2,"C04M", 0.,0.,+zfpos,  0,"ONLY");
-//
-// Inner frame
-     tpar[0]= iChamber->RInner()-dframep;
-     tpar[1]= iChamber->RInner();
-     tpar[2]= dframez/2;
-     gMC->Gsvolu("C03I", "TUBE", idAlu1, tpar, 3);
-     gMC->Gsvolu("C04I", "TUBE", idAlu1, tpar, 3);
-
-     gMC->Gspos("C03I",1,"C03M", 0.,0.,-zfpos,  0,"ONLY");
-     gMC->Gspos("C03I",2,"C03M", 0.,0.,+zfpos,  0,"ONLY");
-     gMC->Gspos("C04I",1,"C04M", 0.,0.,-zfpos,  0,"ONLY");
-     gMC->Gspos("C04I",2,"C04M", 0.,0.,+zfpos,  0,"ONLY");
+     tpar[2] = dstation/5;
+
+     gMC->Gsvolu("S03M", "TUBE", idAir, tpar, 3);
+     gMC->Gsvolu("S04M", "TUBE", idAir, tpar, 3);
+     gMC->Gspos("S03M", 1, "ALIC", 0., 0., zpos1 , 0, "ONLY");
+     gMC->Gspos("S04M", 1, "ALIC", 0., 0., zpos2 , 0, "ONLY");
+
+// // Aluminium frames
+// // Outer frames
+//      pgpar[0] = 360/12/2;
+//      pgpar[1] = 360.;
+//      pgpar[2] = 12.;
+//      pgpar[3] =   2;
+//      pgpar[4] = -dframez/2;
+//      pgpar[5] = iChamber->ROuter();
+//      pgpar[6] = pgpar[5]+dframep;
+//      pgpar[7] = +dframez/2;
+//      pgpar[8] = pgpar[5];
+//      pgpar[9] = pgpar[6];
+//      gMC->Gsvolu("S03O", "PGON", idAlu1, pgpar, 10);
+//      gMC->Gsvolu("S04O", "PGON", idAlu1, pgpar, 10);
+//      gMC->Gspos("S03O",1,"S03M", 0.,0.,-zfpos,  0,"ONLY");
+//      gMC->Gspos("S03O",2,"S03M", 0.,0.,+zfpos,  0,"ONLY");
+//      gMC->Gspos("S04O",1,"S04M", 0.,0.,-zfpos,  0,"ONLY");
+//      gMC->Gspos("S04O",2,"S04M", 0.,0.,+zfpos,  0,"ONLY");
+// //
+// // Inner frame
+//      tpar[0]= iChamber->RInner()-dframep;
+//      tpar[1]= iChamber->RInner();
+//      tpar[2]= dframez/2;
+//      gMC->Gsvolu("S03I", "TUBE", idAlu1, tpar, 3);
+//      gMC->Gsvolu("S04I", "TUBE", idAlu1, tpar, 3);
+
+//      gMC->Gspos("S03I",1,"S03M", 0.,0.,-zfpos,  0,"ONLY");
+//      gMC->Gspos("S03I",2,"S03M", 0.,0.,+zfpos,  0,"ONLY");
+//      gMC->Gspos("S04I",1,"S04M", 0.,0.,-zfpos,  0,"ONLY");
+//      gMC->Gspos("S04I",2,"S04M", 0.,0.,+zfpos,  0,"ONLY");
 //
 // Frame Crosses
-     if (frames) {
-
-        bpar[0] = (iChamber->ROuter() - iChamber->RInner())/2;
-        bpar[1] = dframep/2;
-        bpar[2] = dframez/2;
-        gMC->Gsvolu("C03B", "BOX", idAlu1, bpar, 3);
-        gMC->Gsvolu("C04B", "BOX", idAlu1, bpar, 3);
+     if (frameCrosses) {
+         // outside gas
+         // security for inside mother volume
+        bpar[0] = (iChamber->ROuter() - iChamber->RInner())
+          * TMath::Cos(TMath::ASin(dframep1 /
+                                  (iChamber->ROuter() - iChamber->RInner())))
+          / 2.0;
+        bpar[1] = dframep1/2;
+        // total thickness will be (4 * bpar[2]) for each chamber,
+        // which has to be equal to (2 * dframez) - DAlu
+        bpar[2] = (2.0 * dframez - iChamber->DAlu()) / 4.0;
+        gMC->Gsvolu("S03B", "BOX", idAlu1, bpar, 3);
+        gMC->Gsvolu("S04B", "BOX", idAlu1, bpar, 3);
         
-        gMC->Gspos("C03B",1,"C03M", +iChamber->RInner()+bpar[0] , 0,-zfpos, 
+        gMC->Gspos("S03B",1,"S03M", +iChamber->RInner()+bpar[0] , 0,-zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C03B",2,"C03M", -iChamber->RInner()-bpar[0] , 0,-zfpos, 
+        gMC->Gspos("S03B",2,"S03M", -iChamber->RInner()-bpar[0] , 0,-zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C03B",3,"C03M", 0, +iChamber->RInner()+bpar[0] ,-zfpos, 
+        gMC->Gspos("S03B",3,"S03M", 0, +iChamber->RInner()+bpar[0] ,-zfpos, 
                    idrotm[1101],"ONLY");
-        gMC->Gspos("C03B",4,"C03M", 0, -iChamber->RInner()-bpar[0] ,-zfpos, 
+        gMC->Gspos("S03B",4,"S03M", 0, -iChamber->RInner()-bpar[0] ,-zfpos, 
                    idrotm[1101],"ONLY");
-        gMC->Gspos("C03B",5,"C03M", +iChamber->RInner()+bpar[0] , 0,+zfpos, 
+        gMC->Gspos("S03B",5,"S03M", +iChamber->RInner()+bpar[0] , 0,+zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C03B",6,"C03M", -iChamber->RInner()-bpar[0] , 0,+zfpos, 
+        gMC->Gspos("S03B",6,"S03M", -iChamber->RInner()-bpar[0] , 0,+zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C03B",7,"C03M", 0, +iChamber->RInner()+bpar[0] ,+zfpos, 
+        gMC->Gspos("S03B",7,"S03M", 0, +iChamber->RInner()+bpar[0] ,+zfpos, 
                    idrotm[1101],"ONLY");
-        gMC->Gspos("C03B",8,"C03M", 0, -iChamber->RInner()-bpar[0] ,+zfpos, 
+        gMC->Gspos("S03B",8,"S03M", 0, -iChamber->RInner()-bpar[0] ,+zfpos, 
                    idrotm[1101],"ONLY");
         
-        gMC->Gspos("C04B",1,"C04M", +iChamber->RInner()+bpar[0] , 0,-zfpos, 
+        gMC->Gspos("S04B",1,"S04M", +iChamber->RInner()+bpar[0] , 0,-zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C04B",2,"C04M", -iChamber->RInner()-bpar[0] , 0,-zfpos, 
+        gMC->Gspos("S04B",2,"S04M", -iChamber->RInner()-bpar[0] , 0,-zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C04B",3,"C04M", 0, +iChamber->RInner()+bpar[0] ,-zfpos, 
+        gMC->Gspos("S04B",3,"S04M", 0, +iChamber->RInner()+bpar[0] ,-zfpos, 
                    idrotm[1101],"ONLY");
-        gMC->Gspos("C04B",4,"C04M", 0, -iChamber->RInner()-bpar[0] ,-zfpos, 
+        gMC->Gspos("S04B",4,"S04M", 0, -iChamber->RInner()-bpar[0] ,-zfpos, 
                    idrotm[1101],"ONLY");
-        gMC->Gspos("C04B",5,"C04M", +iChamber->RInner()+bpar[0] , 0,+zfpos, 
+        gMC->Gspos("S04B",5,"S04M", +iChamber->RInner()+bpar[0] , 0,+zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C04B",6,"C04M", -iChamber->RInner()-bpar[0] , 0,+zfpos, 
+        gMC->Gspos("S04B",6,"S04M", -iChamber->RInner()-bpar[0] , 0,+zfpos, 
                    idrotm[1100],"ONLY");
-        gMC->Gspos("C04B",7,"C04M", 0, +iChamber->RInner()+bpar[0] ,+zfpos, 
+        gMC->Gspos("S04B",7,"S04M", 0, +iChamber->RInner()+bpar[0] ,+zfpos, 
                    idrotm[1101],"ONLY");
-        gMC->Gspos("C04B",8,"C04M", 0, -iChamber->RInner()-bpar[0] ,+zfpos, 
+        gMC->Gspos("S04B",8,"S04M", 0, -iChamber->RInner()-bpar[0] ,+zfpos, 
                    idrotm[1101],"ONLY");
      }
 //
@@ -398,89 +525,55 @@ void AliMUONv1::CreateGeometry()
      tpar[0]= iChamber->RInner();
      tpar[1]= iChamber->ROuter();
      tpar[2] = (iChamber->DGas()+iChamber->DAlu())/2;
-     gMC->Gsvolu("C03A", "TUBE", idAlu2, tpar, 3);
-     gMC->Gsvolu("C04A", "TUBE", idAlu2, tpar, 3);
-     gMC->Gspos("C03A", 1, "C03M", 0., 0., 0.,  0, "ONLY");
-     gMC->Gspos("C04A", 1, "C04M", 0., 0., 0.,  0, "ONLY");
+     gMC->Gsvolu("S03A", "TUBE", idAlu2, tpar, 3);
+     gMC->Gsvolu("S04A", "TUBE", idAlu2, tpar, 3);
+     gMC->Gspos("S03A", 1, "S03M", 0., 0., 0.,  0, "ONLY");
+     gMC->Gspos("S04A", 1, "S04M", 0., 0., 0.,  0, "ONLY");
 //     
 //   Sensitive volumes
      // tpar[2] = iChamber->DGas();
      tpar[2] = iChamber->DGas()/2;
-     gMC->Gsvolu("C03G", "TUBE", idGas, tpar, 3);
-     gMC->Gsvolu("C04G", "TUBE", idGas, tpar, 3);
-     gMC->Gspos("C03G", 1, "C03A", 0., 0., 0.,  0, "ONLY");
-     gMC->Gspos("C04G", 1, "C04A", 0., 0., 0.,  0, "ONLY");
-
-     if (frames) {
+     gMC->Gsvolu("S03G", "TUBE", idGas, tpar, 3);
+     gMC->Gsvolu("S04G", "TUBE", idGas, tpar, 3);
+     gMC->Gspos("S03G", 1, "S03A", 0., 0., 0.,  0, "ONLY");
+     gMC->Gspos("S04G", 1, "S04A", 0., 0., 0.,  0, "ONLY");
 //
 // Frame Crosses to be placed inside gas 
-        dr = (iChamber->ROuter() - iChamber->RInner());
-        bpar[0] = TMath::Sqrt(dr*dr-dframep*dframep/4)/2;
-        bpar[1] = dframep/2;
-        bpar[2] = iChamber->DGas()/2;
-        gMC->Gsvolu("C03F", "BOX", idAlu1, bpar, 3);
-        gMC->Gsvolu("C04F", "BOX", idAlu1, bpar, 3);
+     // NONE: chambers are sensitive everywhere
+//      if (frameCrosses) {
+
+//      dr = (iChamber->ROuter() - iChamber->RInner());
+//      bpar[0] = TMath::Sqrt(dr*dr-dframep1*dframep1/4)/2;
+//      bpar[1] = dframep1/2;
+//      bpar[2] = iChamber->DGas()/2;
+//      gMC->Gsvolu("S03F", "BOX", idAlu1, bpar, 3);
+//      gMC->Gsvolu("S04F", "BOX", idAlu1, bpar, 3);
         
-        gMC->Gspos("C03F",1,"C03G", +iChamber->RInner()+bpar[0] , 0, 0, 
-                   idrotm[1100],"ONLY");
-        gMC->Gspos("C03F",2,"C03G", -iChamber->RInner()-bpar[0] , 0, 0, 
-                   idrotm[1100],"ONLY");
-        gMC->Gspos("C03F",3,"C03G", 0, +iChamber->RInner()+bpar[0] , 0, 
-                   idrotm[1101],"ONLY");
-        gMC->Gspos("C03F",4,"C03G", 0, -iChamber->RInner()-bpar[0] , 0, 
-                   idrotm[1101],"ONLY");
+//      gMC->Gspos("S03F",1,"S03G", +iChamber->RInner()+bpar[0] , 0, 0, 
+//                 idrotm[1100],"ONLY");
+//      gMC->Gspos("S03F",2,"S03G", -iChamber->RInner()-bpar[0] , 0, 0, 
+//                 idrotm[1100],"ONLY");
+//      gMC->Gspos("S03F",3,"S03G", 0, +iChamber->RInner()+bpar[0] , 0, 
+//                 idrotm[1101],"ONLY");
+//      gMC->Gspos("S03F",4,"S03G", 0, -iChamber->RInner()-bpar[0] , 0, 
+//                 idrotm[1101],"ONLY");
         
-        gMC->Gspos("C04F",1,"C04G", +iChamber->RInner()+bpar[0] , 0, 0, 
-                   idrotm[1100],"ONLY");
-        gMC->Gspos("C04F",2,"C04G", -iChamber->RInner()-bpar[0] , 0, 0, 
-                   idrotm[1100],"ONLY");
-        gMC->Gspos("C04F",3,"C04G", 0, +iChamber->RInner()+bpar[0] , 0, 
-                   idrotm[1101],"ONLY");
-        gMC->Gspos("C04F",4,"C04G", 0, -iChamber->RInner()-bpar[0] , 0, 
-                   idrotm[1101],"ONLY");
+//      gMC->Gspos("S04F",1,"S04G", +iChamber->RInner()+bpar[0] , 0, 0, 
+//                 idrotm[1100],"ONLY");
+//      gMC->Gspos("S04F",2,"S04G", -iChamber->RInner()-bpar[0] , 0, 0, 
+//                 idrotm[1100],"ONLY");
+//      gMC->Gspos("S04F",3,"S04G", 0, +iChamber->RInner()+bpar[0] , 0, 
+//                 idrotm[1101],"ONLY");
+//      gMC->Gspos("S04F",4,"S04G", 0, -iChamber->RInner()-bpar[0] , 0, 
+//                 idrotm[1101],"ONLY");
+//      }
      }
-      
-//********************************************************************
-//                            Station 3                             **
-//********************************************************************
-     // indices 1 and 2 for first and second chambers in the station
-     // iChamber (first chamber) kept for other quanties than Z,
-     // assumed to be the same in both chambers
-     iChamber1 = iChamber = (AliMUONChamber*) (*fChambers)[4];
-     iChamber2 =(AliMUONChamber*) (*fChambers)[5];
-     zpos1=iChamber1->Z(); 
-     zpos2=iChamber2->Z();
-     dstation = zpos2 - zpos1;
-
-     zfpos=-(iChamber->DGas()+dframez+iChamber->DAlu())/2;
-//
-//   Mother volume
-     tpar[0] = iChamber->RInner()-dframep; 
-     tpar[1] = (iChamber->ROuter()+dframep)/TMath::Cos(phi);
-     tpar[2] = dstation/4;
-     gMC->Gsvolu("C05M", "TUBE", idAir, tpar, 3);
-     gMC->Gsvolu("C06M", "TUBE", idAir, tpar, 3);
-     gMC->Gspos("C05M", 1, "ALIC", 0., 0., zpos1 , 0, "ONLY");
-     gMC->Gspos("C06M", 1, "ALIC", 0., 0., zpos2 , 0, "ONLY");
-     // volumes for slat geometry (xx=5,..,10 chamber id): 
-     // Sxx0 Sxx1 Sxx2 Sxx3  -->   Slat Mother volumes 
-     // SxxG                          -->   Sensitive volume (gas)
-     // SxxP                          -->   PCB (copper) 
-     // SxxI                          -->   Insulator (vetronite) 
-     // SxxC                          -->   Carbon panel 
-     // SxxR                          -->   Rohacell
-     // SxxH, SxxV                    -->   Horizontal and Vertical frames (vetronite)
-
      // define the id of tracking media:
      Int_t idCopper = idtmed[1110];
      Int_t idGlass  = idtmed[1111];
      Int_t idCarbon = idtmed[1112];
      Int_t idRoha   = idtmed[1113];
 
-     const Int_t nSlats3 = 4;  // number of slats per quadrant
-     const Int_t nPCB3[nSlats3] = {4,4,3,2}; // n PCB per slat
-
       // sensitive area: 40*40 cm**2
      const Float_t sensLength = 40.; 
      const Float_t sensHeight = 40.; 
@@ -537,178 +630,319 @@ void AliMUONv1::CreateGeometry()
      const Float_t nulocWidth  = 0.0030 + 0.0014; // equivalent copper width of vetronite; 
      const Int_t   nulocMaterial = idCopper;
 
-     // Gassiplex package 
-     const Float_t gassiLength   = 1.0; 
-     const Float_t gassiHeight   = 1.0; 
-     const Float_t gassiWidth    = 0.15; // check it !!!
-     const Int_t   gassiMaterial = idGlass; 
-
-     // slat dimensions: slat is a MOTHER volume!!! made of air
-     Float_t slatLength[nSlats3]; 
      const Float_t slatHeight = pcbHeight; 
      const Float_t slatWidth = sensWidth + 2.*(pcbWidth + insuWidth + 
                                               2.* panelWidth + rohaWidth);
      const Int_t slatMaterial = idAir;
      const Float_t dSlatLength = vFrameLength; // border on left and right 
 
-     // create and position the slat (mother) volumes 
      Float_t spar[3];  
+     Int_t i, j;
+
+     // the panel volume contains the rohacell
+
+     Float_t twidth = 2 * panelWidth + rohaWidth; 
+     Float_t panelpar[3] = { panelLength/2., panelHeight/2., twidth/2. }; 
+     Float_t rohapar[3] = { rohaLength/2., rohaHeight/2., rohaWidth/2. }; 
+
+     // insulating material contains PCB-> gas-> 2 borders filled with rohacell
+
+     twidth = 2*(insuWidth + pcbWidth) + sensWidth;  
+     Float_t insupar[3] = { insuLength/2., insuHeight/2., twidth/2. }; 
+     twidth -= 2 * insuWidth; 
+     Float_t pcbpar[3] = { pcbLength/2., pcbHeight/2., twidth/2. }; 
+     Float_t senspar[3] = { sensLength/2., sensHeight/2., sensWidth/2. }; 
+     Float_t theight = 2*hFrameHeight + sensHeight;
+     Float_t hFramepar[3]={hFrameLength/2., theight/2., hFrameWidth/2.}; 
+     Float_t bFramepar[3]={bFrameLength/2., bFrameHeight/2., bFrameWidth/2.}; 
+     Float_t vFramepar[3]={vFrameLength/2., vFrameHeight/2., vFrameWidth/2.}; 
+     Float_t nulocpar[3]={nulocLength/2., nulocHeight/2., nulocWidth/2.}; 
+     Float_t xx;
+     Float_t xxmax = (bFrameLength - nulocLength)/2.; 
+     Int_t index=0;
+     
+     if (stations[2]) {
+        
+//********************************************************************
+//                            Station 3                             **
+//********************************************************************
+     // indices 1 and 2 for first and second chambers in the station
+     // iChamber (first chamber) kept for other quanties than Z,
+     // assumed to be the same in both chambers
+     iChamber1 = iChamber = (AliMUONChamber*) (*fChambers)[4];
+     iChamber2 =(AliMUONChamber*) (*fChambers)[5];
+     zpos1=iChamber1->Z(); 
+     zpos2=iChamber2->Z();
+     dstation = zpos2 - zpos1;
+
+//      zfpos=-(iChamber->DGas()+dframez+iChamber->DAlu())/2; // not used any more
+//
+//   Mother volume
+     tpar[0] = iChamber->RInner()-dframep; 
+     tpar[1] = (iChamber->ROuter()+dframep)/TMath::Cos(phi);
+     tpar[2] = dstation/5;
+
+     char *slats5Mother = "S05M";
+     char *slats6Mother = "S06M";
+     Float_t zoffs5 = 0;
+     Float_t zoffs6 = 0;
+
+     if (gAlice->GetModule("DIPO")) {
+       slats5Mother="DDIP";
+       slats6Mother="DDIP";
+
+       zoffs5 = zpos1;
+       zoffs6 = zpos2;
+     }
+     else {
+       gMC->Gsvolu("S05M", "TUBE", idAir, tpar, 3);
+       gMC->Gsvolu("S06M", "TUBE", idAir, tpar, 3);
+       gMC->Gspos("S05M", 1, "ALIC", 0., 0., zpos1 , 0, "ONLY");
+       gMC->Gspos("S06M", 1, "ALIC", 0., 0., zpos2 , 0, "ONLY");
+     }
+
+     // volumes for slat geometry (xx=5,..,10 chamber id): 
+     // Sxx0 Sxx1 Sxx2 Sxx3  -->   Slat Mother volumes 
+     // SxxG                          -->   Sensitive volume (gas)
+     // SxxP                          -->   PCB (copper) 
+     // SxxI                          -->   Insulator (vetronite) 
+     // SxxC                          -->   Carbon panel 
+     // SxxR                          -->   Rohacell
+     // SxxH, SxxV                    -->   Horizontal and Vertical frames (vetronite)
+     // SB5x                          -->   Volumes for the 35 cm long PCB
+     // slat dimensions: slat is a MOTHER volume!!! made of air
+
+     // only for chamber 5: slat 1 has a PCB shorter by 5cm!
+
+     Float_t tlength = 35.;
+     Float_t panelpar2[3]  = { tlength/2., panelpar[1],  panelpar[2]}; 
+     Float_t rohapar2[3]   = { tlength/2., rohapar[1],   rohapar[2]}; 
+     Float_t insupar2[3]   = { tlength/2., insupar[1],   insupar[2]}; 
+     Float_t pcbpar2[3]    = { tlength/2., pcbpar[1],    pcbpar[2]}; 
+     Float_t senspar2[3]   = { tlength/2., senspar[1],   senspar[2]}; 
+     Float_t hFramepar2[3] = { tlength/2., hFramepar[1], hFramepar[2]}; 
+     Float_t bFramepar2[3] = { tlength/2., bFramepar[1], bFramepar[2]}; 
+
+     const Int_t nSlats3 = 5;  // number of slats per quadrant
+     const Int_t nPCB3[nSlats3] = {3,3,4,3,2}; // n PCB per slat
+     const Float_t xpos3[nSlats3] = {31., 40., 0., 0., 0.};
+     Float_t slatLength3[nSlats3]; 
+
+     // create and position the slat (mother) volumes 
+
      char volNam5[5];
      char volNam6[5];
-     Float_t xSlat[nSlats3];
-     Float_t ySlat[nSlats3];
-     Int_t i, j;
+     Float_t xSlat3;
+
+     Float_t spar2[3];
      for (i = 0; i<nSlats3; i++){
-       slatLength[i] = pcbLength * nPCB3[i] + 2. * dSlatLength; 
-       xSlat[i] = slatLength[i]/2.; 
-       ySlat[i] = sensHeight * (i+0.5) - yOverlap * i; 
-       spar[0] = slatLength[i]/2.; 
+       slatLength3[i] = pcbLength * nPCB3[i] + 2. * dSlatLength; 
+       xSlat3 = slatLength3[i]/2. - vFrameLength/2. + xpos3[i]; 
+       if (i==1 || i==0) slatLength3[i] -=  2. *dSlatLength; // frame out in PCB with circular border 
+       Float_t ySlat31 =  sensHeight * i - yOverlap * i; 
+       Float_t ySlat32 = -sensHeight * i + yOverlap * i; 
+       spar[0] = slatLength3[i]/2.; 
        spar[1] = slatHeight/2.;
-       spar[2] = slatWidth/2.; 
+       spar[2] = slatWidth/2. * 1.01; 
+       // take away 5 cm from the first slat in chamber 5
+       Float_t xSlat32 = 0;
+       if (i==1 || i==2) { // 1 pcb is shortened by 5cm
+        spar2[0] = spar[0]-5./2.;
+        xSlat32 = xSlat3 - 5/2.;
+       }
+       else {
+        spar2[0] = spar[0];
+        xSlat32 = xSlat3;
+       }
+       spar2[1] = spar[1];
+       spar2[2] = spar[2]; 
+       Float_t dzCh3=spar[2] * 1.01;
        // zSlat to be checked (odd downstream or upstream?)
-       Float_t zSlat = (i%2 ==0)? -slatWidth/2. : slatWidth/2.
+       Float_t zSlat = (i%2 ==0)? -spar[2] : spar[2]
        sprintf(volNam5,"S05%d",i);
-       gMC->Gsvolu(volNam5,"BOX",slatMaterial,spar,3);
-       gMC->Gspos(volNam5, i*4+1,"C05M", xSlat[i], ySlat[i], zSlat, 0, "ONLY");
-       gMC->Gspos(volNam5, i*4+2,"C05M",-xSlat[i], ySlat[i], zSlat, 0, "ONLY");
-       gMC->Gspos(volNam5, i*4+3,"C05M", xSlat[i],-ySlat[i],-zSlat, 0, "ONLY");
-       gMC->Gspos(volNam5, i*4+4,"C05M",-xSlat[i],-ySlat[i],-zSlat, 0, "ONLY");
+       gMC->Gsvolu(volNam5,"BOX",slatMaterial,spar2,3);
+       gMC->Gspos(volNam5, i*4+1,slats5Mother, xSlat32, ySlat31, zoffs5+zSlat+2.*dzCh3, 0, "ONLY");
+       gMC->Gspos(volNam5, i*4+2,slats5Mother,-xSlat32, ySlat31, zoffs5+zSlat-2.*dzCh3, 0, "ONLY");
+       
+       if (i>0) { 
+        gMC->Gspos(volNam5, i*4+3,slats5Mother, xSlat32, ySlat32, zoffs5+zSlat+2.*dzCh3, 0, "ONLY");
+        gMC->Gspos(volNam5, i*4+4,slats5Mother,-xSlat32, ySlat32, zoffs5+zSlat-2.*dzCh3, 0, "ONLY");
+       }
        sprintf(volNam6,"S06%d",i);
        gMC->Gsvolu(volNam6,"BOX",slatMaterial,spar,3);
-       gMC->Gspos(volNam6, i*4+1,"C06M", xSlat[i], ySlat[i], zSlat, 0, "ONLY");
-       gMC->Gspos(volNam6, i*4+2,"C06M",-xSlat[i], ySlat[i], zSlat, 0, "ONLY");
-       gMC->Gspos(volNam6, i*4+3,"C06M", xSlat[i],-ySlat[i],-zSlat, 0, "ONLY");
-       gMC->Gspos(volNam6, i*4+4,"C06M",-xSlat[i],-ySlat[i],-zSlat, 0, "ONLY");
+       gMC->Gspos(volNam6, i*4+1,slats6Mother, xSlat3, ySlat31, zoffs6+zSlat+2.*dzCh3, 0, "ONLY");
+       gMC->Gspos(volNam6, i*4+2,slats6Mother,-xSlat3, ySlat31, zoffs6+zSlat-2.*dzCh3, 0, "ONLY");
+       if (i>0) { 
+        gMC->Gspos(volNam6, i*4+3,slats6Mother, xSlat3, ySlat32, zoffs6+zSlat+2.*dzCh3, 0, "ONLY");
+        gMC->Gspos(volNam6, i*4+4,slats6Mother,-xSlat3, ySlat32, zoffs6+zSlat-2.*dzCh3, 0, "ONLY");
+       }
      }
 
-     // create the sensitive volumes (subdivided as the PCBs),
-     Float_t sensPar[3] = { sensLength/2., sensHeight/2., sensWidth/2. }; 
-     gMC->Gsvolu("S05G","BOX",sensMaterial,sensPar,3);
-     gMC->Gsvolu("S06G","BOX",sensMaterial,sensPar,3);
-
-     // create the PCB volume 
-     Float_t pcbpar[3] = { pcbLength/2., pcbHeight/2., pcbWidth/2. }; 
-     gMC->Gsvolu("S05P","BOX",pcbMaterial,pcbpar,3);
-     gMC->Gsvolu("S06P","BOX",pcbMaterial,pcbpar,3);
-     // create the insulating material volume 
-     Float_t insupar[3] = { insuLength/2., insuHeight/2., insuWidth/2. }; 
-     gMC->Gsvolu("S05I","BOX",insuMaterial,insupar,3);
-     gMC->Gsvolu("S06I","BOX",insuMaterial,insupar,3);
-
      // create the panel volume 
-     Float_t panelpar[3] = { panelLength/2., panelHeight/2., panelWidth/2. }; 
      gMC->Gsvolu("S05C","BOX",panelMaterial,panelpar,3);
+     gMC->Gsvolu("SB5C","BOX",panelMaterial,panelpar2,3);
      gMC->Gsvolu("S06C","BOX",panelMaterial,panelpar,3);
 
      // create the rohacell volume 
-     Float_t rohapar[3] = { rohaLength/2., rohaHeight/2., rohaWidth/2. }; 
+
      gMC->Gsvolu("S05R","BOX",rohaMaterial,rohapar,3);
+     gMC->Gsvolu("SB5R","BOX",rohaMaterial,rohapar2,3);
      gMC->Gsvolu("S06R","BOX",rohaMaterial,rohapar,3);
 
+     // create the insulating material volume 
+
+     gMC->Gsvolu("S05I","BOX",insuMaterial,insupar,3);
+     gMC->Gsvolu("SB5I","BOX",insuMaterial,insupar2,3);
+     gMC->Gsvolu("S06I","BOX",insuMaterial,insupar,3);
+
+     // create the PCB volume 
+
+     gMC->Gsvolu("S05P","BOX",pcbMaterial,pcbpar,3);
+     gMC->Gsvolu("SB5P","BOX",pcbMaterial,pcbpar2,3);
+     gMC->Gsvolu("S06P","BOX",pcbMaterial,pcbpar,3);
+     // create the sensitive volumes,
+     gMC->Gsvolu("S05G","BOX",sensMaterial,dum,0);
+     gMC->Gsvolu("S06G","BOX",sensMaterial,dum,0);
+
+
      // create the vertical frame volume 
-     Float_t vFramepar[3]={vFrameLength/2., vFrameHeight/2., vFrameWidth/2.}; 
+
      gMC->Gsvolu("S05V","BOX",vFrameMaterial,vFramepar,3);
      gMC->Gsvolu("S06V","BOX",vFrameMaterial,vFramepar,3);
 
      // create the horizontal frame volume 
-     Float_t hFramepar[3]={hFrameLength/2., hFrameHeight/2., hFrameWidth/2.}; 
+
      gMC->Gsvolu("S05H","BOX",hFrameMaterial,hFramepar,3);
+     gMC->Gsvolu("SB5H","BOX",hFrameMaterial,hFramepar2,3);
      gMC->Gsvolu("S06H","BOX",hFrameMaterial,hFramepar,3);
 
      // create the horizontal border volume 
-     Float_t bFramepar[3]={bFrameLength/2., bFrameHeight/2., bFrameWidth/2.}; 
+
      gMC->Gsvolu("S05B","BOX",bFrameMaterial,bFramepar,3);
+     gMC->Gsvolu("SB5B","BOX",bFrameMaterial,bFramepar2,3);
      gMC->Gsvolu("S06B","BOX",bFrameMaterial,bFramepar,3);
 
-     Int_t index=0; 
+     index=0; 
      for (i = 0; i<nSlats3; i++){
        sprintf(volNam5,"S05%d",i);
        sprintf(volNam6,"S06%d",i);
-       Float_t xvFrame  = (slatLength[i] - vFrameLength)/2.;
-       gMC->Gspos("S05V",2*i-1,volNam5, xvFrame, 0., 0. , 0, "ONLY");
-       gMC->Gspos("S05V",2*i  ,volNam5,-xvFrame, 0., 0. , 0, "ONLY");
-       gMC->Gspos("S06V",2*i-1,volNam6, xvFrame, 0., 0. , 0, "ONLY");
-       gMC->Gspos("S06V",2*i  ,volNam6,-xvFrame, 0., 0. , 0, "ONLY");
+       Float_t xvFrame  = (slatLength3[i] - vFrameLength)/2.;
+       Float_t xvFrame2  = xvFrame;
+       if ( i==1 || i ==2 ) xvFrame2 -= 5./2.;
+       // position the vertical frames 
+       if (i!=1 && i!=0) { 
+        gMC->Gspos("S05V",2*i-1,volNam5, xvFrame2, 0., 0. , 0, "ONLY");
+        gMC->Gspos("S05V",2*i  ,volNam5,-xvFrame2, 0., 0. , 0, "ONLY");
+        gMC->Gspos("S06V",2*i-1,volNam6, xvFrame, 0., 0. , 0, "ONLY");
+        gMC->Gspos("S06V",2*i  ,volNam6,-xvFrame, 0., 0. , 0, "ONLY");
+       }       
+       // position the panels and the insulating material 
        for (j=0; j<nPCB3[i]; j++){
         index++;
         Float_t xx = sensLength * (-nPCB3[i]/2.+j+.5); 
-        Float_t yy = 0.;
-        Float_t zSens = 0.;  
-        gMC->Gspos("S05G",index,volNam5, xx, yy, zSens , 0, "ONLY");
-        gMC->Gspos("S06G",index,volNam6, xx, yy, zSens , 0, "ONLY");
-        Float_t zPCB = (sensWidth+pcbWidth)/2.; 
-        gMC->Gspos("S05P",2*index-1,volNam5, xx, yy, zPCB , 0, "ONLY");
-        gMC->Gspos("S05P",2*index  ,volNam5, xx, yy,-zPCB , 0, "ONLY");
-        gMC->Gspos("S06P",2*index-1,volNam6, xx, yy, zPCB , 0, "ONLY");
-        gMC->Gspos("S06P",2*index  ,volNam6, xx, yy,-zPCB , 0, "ONLY");
-        Float_t zInsu = (insuWidth+pcbWidth)/2. + zPCB; 
-        gMC->Gspos("S05I",2*index-1,volNam5, xx, yy, zInsu , 0, "ONLY");
-        gMC->Gspos("S05I",2*index  ,volNam5, xx, yy,-zInsu , 0, "ONLY");
-        gMC->Gspos("S06I",2*index-1,volNam6, xx, yy, zInsu , 0, "ONLY");
-        gMC->Gspos("S06I",2*index  ,volNam6, xx, yy,-zInsu , 0, "ONLY");
-        Float_t zPanel1 = (insuWidth+panelWidth)/2. + zInsu; 
-        gMC->Gspos("S05C",4*index-3,volNam5, xx, yy, zPanel1 , 0, "ONLY");
-        gMC->Gspos("S05C",4*index-2,volNam5, xx, yy,-zPanel1 , 0, "ONLY");
-        gMC->Gspos("S06C",4*index-3,volNam6, xx, yy, zPanel1 , 0, "ONLY");
-        gMC->Gspos("S06C",4*index-2,volNam6, xx, yy,-zPanel1 , 0, "ONLY");
-        Float_t zRoha = (rohaWidth+panelWidth)/2. + zPanel1; 
-        gMC->Gspos("S05R",2*index-1,volNam5, xx, yy, zRoha , 0, "ONLY");
-        gMC->Gspos("S05R",2*index  ,volNam5, xx, yy,-zRoha , 0, "ONLY");
-        gMC->Gspos("S06R",2*index-1,volNam6, xx, yy, zRoha , 0, "ONLY");
-        gMC->Gspos("S06R",2*index  ,volNam6, xx, yy,-zRoha , 0, "ONLY");
-        Float_t zPanel2 = (rohaWidth+panelWidth)/2. + zRoha; 
-        gMC->Gspos("S05C",4*index-1,volNam5, xx, yy, zPanel2 , 0, "ONLY");
-        gMC->Gspos("S05C",4*index  ,volNam5, xx, yy,-zPanel2 , 0, "ONLY");
-        gMC->Gspos("S06C",4*index-1,volNam6, xx, yy, zPanel2 , 0, "ONLY");
-        gMC->Gspos("S06C",4*index  ,volNam6, xx, yy,-zPanel2 , 0, "ONLY");
-        Float_t yframe = (sensHeight + hFrameHeight)/2.;
-        gMC->Gspos("S05H",2*index-1,volNam5, xx, yframe, 0. , 0, "ONLY");
-        gMC->Gspos("S05H",2*index  ,volNam5, xx,-yframe, 0. , 0, "ONLY");
-        gMC->Gspos("S06H",2*index-1,volNam6, xx, yframe, 0. , 0, "ONLY");
-        gMC->Gspos("S06H",2*index  ,volNam6, xx,-yframe, 0. , 0, "ONLY");
-        Float_t yborder = (bFrameHeight + hFrameHeight)/2. + yframe;
-        gMC->Gspos("S05B",2*index-1,volNam5, xx, yborder, 0. , 0, "ONLY");
-        gMC->Gspos("S05B",2*index  ,volNam5, xx,-yborder, 0. , 0, "ONLY");
-        gMC->Gspos("S06B",2*index-1,volNam6, xx, yborder, 0. , 0, "ONLY");
-        gMC->Gspos("S06B",2*index  ,volNam6, xx,-yborder, 0. , 0, "ONLY");
+        Float_t xx2 = xx + 5/2.; 
+        
+        Float_t zPanel = spar[2] - panelpar[2]; 
+        if ( (i==1 || i==2) && j == nPCB3[i]-1) { // 1 pcb is shortened by 5cm 
+          gMC->Gspos("SB5C",2*index-1,volNam5, xx, 0., zPanel , 0, "ONLY");
+          gMC->Gspos("SB5C",2*index  ,volNam5, xx, 0.,-zPanel , 0, "ONLY");
+          gMC->Gspos("SB5I",index    ,volNam5, xx, 0., 0      , 0, "ONLY");
+        }
+        else if ( (i==1 || i==2) && j < nPCB3[i]-1) {
+          gMC->Gspos("S05C",2*index-1,volNam5, xx2, 0., zPanel , 0, "ONLY");
+          gMC->Gspos("S05C",2*index  ,volNam5, xx2, 0.,-zPanel , 0, "ONLY");
+          gMC->Gspos("S05I",index    ,volNam5, xx2, 0., 0 , 0, "ONLY");
+        }
+        else {
+          gMC->Gspos("S05C",2*index-1,volNam5, xx, 0., zPanel , 0, "ONLY");
+          gMC->Gspos("S05C",2*index  ,volNam5, xx, 0.,-zPanel , 0, "ONLY");
+          gMC->Gspos("S05I",index    ,volNam5, xx, 0., 0 , 0, "ONLY");
+        }
+        gMC->Gspos("S06C",2*index-1,volNam6, xx, 0., zPanel , 0, "ONLY");
+        gMC->Gspos("S06C",2*index  ,volNam6, xx, 0.,-zPanel , 0, "ONLY");
+        gMC->Gspos("S06I",index,volNam6, xx, 0., 0 , 0, "ONLY");
        } 
      }
+     
+     // position the rohacell volume inside the panel volume
+     gMC->Gspos("S05R",1,"S05C",0.,0.,0.,0,"ONLY"); 
+     gMC->Gspos("SB5R",1,"SB5C",0.,0.,0.,0,"ONLY"); 
+     gMC->Gspos("S06R",1,"S06C",0.,0.,0.,0,"ONLY"); 
+
+     // position the PCB volume inside the insulating material volume
+     gMC->Gspos("S05P",1,"S05I",0.,0.,0.,0,"ONLY"); 
+     gMC->Gspos("SB5P",1,"SB5I",0.,0.,0.,0,"ONLY"); 
+     gMC->Gspos("S06P",1,"S06I",0.,0.,0.,0,"ONLY"); 
+     // position the horizontal frame volume inside the PCB volume
+     gMC->Gspos("S05H",1,"S05P",0.,0.,0.,0,"ONLY"); 
+     gMC->Gspos("SB5H",1,"SB5P",0.,0.,0.,0,"ONLY"); 
+     gMC->Gspos("S06H",1,"S06P",0.,0.,0.,0,"ONLY"); 
+     // position the sensitive volume inside the horizontal frame volume
+     gMC->Gsposp("S05G",1,"S05H",0.,0.,0.,0,"ONLY",senspar,3); 
+     gMC->Gsposp("S05G",1,"SB5H",0.,0.,0.,0,"ONLY",senspar2,3); 
+     gMC->Gsposp("S06G",1,"S06H",0.,0.,0.,0,"ONLY",senspar,3); 
+     // position the border volumes inside the PCB volume
+     Float_t yborder = ( pcbHeight - bFrameHeight ) / 2.; 
+     gMC->Gspos("S05B",1,"S05P",0., yborder,0.,0,"ONLY"); 
+     gMC->Gspos("S05B",2,"S05P",0.,-yborder,0.,0,"ONLY"); 
+     gMC->Gspos("SB5B",1,"SB5P",0., yborder,0.,0,"ONLY"); 
+     gMC->Gspos("SB5B",2,"SB5P",0.,-yborder,0.,0,"ONLY"); 
+     gMC->Gspos("S06B",1,"S06P",0., yborder,0.,0,"ONLY"); 
+     gMC->Gspos("S06B",2,"S06P",0.,-yborder,0.,0,"ONLY"); 
 
      // create the NULOC volume and position it in the horizontal frame
-     Float_t nulocpar[3]={nulocLength/2., nulocHeight/2., nulocWidth/2.}; 
+
      gMC->Gsvolu("S05N","BOX",nulocMaterial,nulocpar,3);
      gMC->Gsvolu("S06N","BOX",nulocMaterial,nulocpar,3);
-
-     Float_t xxmax = (bFrameLength - nulocLength)/2.; 
      index = 0;
-     Float_t xx;
-
-     for (xx = -xxmax; xx<=xxmax; xx+=3*nulocLength) { 
+     Float_t xxmax2 = xxmax - 5./2.;
+     for (xx = -xxmax; xx<=xxmax; xx+=2*nulocLength) { 
        index++; 
        gMC->Gspos("S05N",2*index-1,"S05B", xx, 0.,-bFrameWidth/4., 0, "ONLY");
        gMC->Gspos("S05N",2*index  ,"S05B", xx, 0., bFrameWidth/4., 0, "ONLY");
+       if (xx > -xxmax2 && xx< xxmax2) {
+        gMC->Gspos("S05N",2*index-1,"SB5B", xx, 0.,-bFrameWidth/4., 0, "ONLY");
+        gMC->Gspos("S05N",2*index  ,"SB5B", xx, 0., bFrameWidth/4., 0, "ONLY");
+       }
        gMC->Gspos("S06N",2*index-1,"S06B", xx, 0.,-bFrameWidth/4., 0, "ONLY");
        gMC->Gspos("S06N",2*index  ,"S06B", xx, 0., bFrameWidth/4., 0, "ONLY");
      }
-
-     // create the gassiplex volume 
-     Float_t gassipar[3]={gassiLength/2., gassiHeight/2., gassiWidth/2.}; 
-     gMC->Gsvolu("S05E","BOX",gassiMaterial,gassipar,3);
-     gMC->Gsvolu("S06E","BOX",gassiMaterial,gassipar,3);
-
-
-     // position 4 gassiplex in the nuloc
-
-     gMC->Gspos("S05E",1,"S05N", 0., -3 * nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S05E",2,"S05N", 0.,    - nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S05E",3,"S05N", 0.,      nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S05E",4,"S05N", 0.,  3 * nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S06E",1,"S06N", 0., -3 * nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S06E",2,"S06N", 0.,    - nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S06E",3,"S06N", 0.,      nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S06E",4,"S06N", 0.,  3 * nulocHeight/8., 0. , 0, "ONLY");
-
+     
+     // position the volumes approximating the circular section of the pipe
+     Float_t yoffs = sensHeight/2. - yOverlap; 
+     Float_t epsilon = 0.001; 
+     Int_t ndiv=6;
+     Float_t divpar[3];
+     Double_t dydiv= sensHeight/ndiv;
+     Double_t ydiv = yoffs -dydiv;
+     Int_t imax=0; 
+     imax = 1; 
+     Float_t rmin = 33.; 
+     Float_t z1 = spar[2], z2=2*spar[2]*1.01; 
+     for (Int_t idiv=0;idiv<ndiv; idiv++){ 
+       ydiv+= dydiv;
+       Float_t xdiv = 0.; 
+       if (ydiv<rmin) xdiv= rmin * TMath::Sin( TMath::ACos(ydiv/rmin) );
+       divpar[0] = (pcbLength-xdiv)/2.; 
+       divpar[1] = dydiv/2. - epsilon;
+       divpar[2] = sensWidth/2.; 
+       Float_t xvol=(pcbLength+xdiv)/2.+1.999;
+       Float_t yvol=ydiv + dydiv/2.; 
+       //printf ("y ll = %f y ur = %f \n",yvol - divpar[1], yvol + divpar[1]); 
+       gMC->Gsposp("S05G",imax+4*idiv+1,slats5Mother, xvol, yvol, zoffs5+z1+z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S06G",imax+4*idiv+1,slats6Mother, xvol, yvol, zoffs6+z1+z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S05G",imax+4*idiv+2,slats5Mother, xvol,-yvol, zoffs5+z1+z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S06G",imax+4*idiv+2,slats6Mother, xvol,-yvol, zoffs6+z1+z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S05G",imax+4*idiv+3,slats5Mother,-xvol, yvol, zoffs5+z1-z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S06G",imax+4*idiv+3,slats6Mother,-xvol, yvol, zoffs6+z1-z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S05G",imax+4*idiv+4,slats5Mother,-xvol,-yvol, zoffs5+z1-z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S06G",imax+4*idiv+4,slats6Mother,-xvol,-yvol, zoffs6+z1-z2, 0, "ONLY",divpar,3);
+     }
+     }
+     
+ if (stations[3]) {
 
 //********************************************************************
 //                            Station 4                             **
@@ -721,24 +955,23 @@ void AliMUONv1::CreateGeometry()
      zpos1=iChamber1->Z(); 
      zpos2=iChamber2->Z();
      dstation = zpos2 - zpos1;
-     zfpos=-(iChamber->DGas()+dframez+iChamber->DAlu())/2;
+//      zfpos=-(iChamber->DGas()+dframez+iChamber->DAlu())/2; // not used any more
      
 //
 //   Mother volume
      tpar[0] = iChamber->RInner()-dframep; 
      tpar[1] = (iChamber->ROuter()+dframep)/TMath::Cos(phi);
-     tpar[2] = 3.252;
+     tpar[2] = dstation/4;
 
-     gMC->Gsvolu("C07M", "TUBE", idAir, tpar, 3);
-     gMC->Gsvolu("C08M", "TUBE", idAir, tpar, 3);
-     gMC->Gspos("C07M", 1, "ALIC", 0., 0., zpos1 , 0, "ONLY");
-     gMC->Gspos("C08M", 1, "ALIC", 0., 0., zpos2 , 0, "ONLY");
+     gMC->Gsvolu("S07M", "TUBE", idAir, tpar, 3);
+     gMC->Gsvolu("S08M", "TUBE", idAir, tpar, 3);
+     gMC->Gspos("S07M", 1, "ALIC", 0., 0., zpos1 , 0, "ONLY");
+     gMC->Gspos("S08M", 1, "ALIC", 0., 0., zpos2 , 0, "ONLY");
      
 
-     const Int_t nSlats4 = 7;  // number of slats per quadrant
-     const Int_t nPCB4[nSlats4] = {7,7,6,6,5,4,2}; // n PCB per slat
-
-     // slat dimensions: slat is a MOTHER volume!!! made of air
+     const Int_t nSlats4 = 6;  // number of slats per quadrant
+     const Int_t nPCB4[nSlats4] = {4,4,5,5,4,3}; // n PCB per slat
+     const Float_t xpos4[nSlats4] = {38.5, 40., 0., 0., 0., 0.};
      Float_t slatLength4[nSlats4];     
 
      // create and position the slat (mother) volumes 
@@ -746,60 +979,63 @@ void AliMUONv1::CreateGeometry()
      char volNam7[5];
      char volNam8[5];
      Float_t xSlat4;
-     Float_t ySlat41, ySlat42;
-
+     Float_t ySlat4;
 
      for (i = 0; i<nSlats4; i++){
-        slatLength4[i] = pcbLength * nPCB4[i] + 2. * dSlatLength; 
-        xSlat4 = slatLength4[i]/2.; 
-        if (i==0) xSlat4 += 30.;
-        
-        ySlat41 =  sensHeight * (i+0.5) - yOverlap *i - yOverlap/2.;
-        ySlat42 = -sensHeight * (i+0.5) + yOverlap *i + yOverlap/2.;
-        
-        spar[0] = slatLength4[i]/2.; 
-        spar[1] = slatHeight/2.;
-        spar[2] = slatWidth/2.; 
-        // zSlat to be checked (odd downstream or upstream?)
-        Float_t zSlat = (i%2 ==0)? slatWidth/2. : -slatWidth/2.; 
-        sprintf(volNam7,"S07%d",i);
-        gMC->Gsvolu(volNam7,"BOX",slatMaterial,spar,3);
-        gMC->Gspos(volNam7, i*4+1,"C07M", xSlat4, ySlat41, -zSlat, 0, "ONLY");
-        gMC->Gspos(volNam7, i*4+2,"C07M",-xSlat4, ySlat41, -zSlat, 0, "ONLY");
-        gMC->Gspos(volNam7, i*4+3,"C07M", xSlat4, ySlat42,  zSlat, 0, "ONLY");
-        gMC->Gspos(volNam7, i*4+4,"C07M",-xSlat4, ySlat42,  zSlat, 0, "ONLY");
-        sprintf(volNam8,"S08%d",i);
-        gMC->Gsvolu(volNam8,"BOX",slatMaterial,spar,3);
-        gMC->Gspos(volNam8, i*4+1,"C08M", xSlat4, ySlat41, -zSlat, 0, "ONLY");
-        gMC->Gspos(volNam8, i*4+2,"C08M",-xSlat4, ySlat41, -zSlat, 0, "ONLY");
-        gMC->Gspos(volNam8, i*4+3,"C08M", xSlat4, ySlat42,  zSlat, 0, "ONLY");
-        gMC->Gspos(volNam8, i*4+4,"C08M",-xSlat4, ySlat42,  zSlat, 0, "ONLY");
+       slatLength4[i] = pcbLength * nPCB4[i] + 2. * dSlatLength; 
+       xSlat4 = slatLength4[i]/2. - vFrameLength/2. + xpos4[i]; 
+       if (i==1) slatLength4[i] -=  2. *dSlatLength; // frame out in PCB with circular border 
+       ySlat4 =  sensHeight * i - yOverlap *i;
+       
+       spar[0] = slatLength4[i]/2.; 
+       spar[1] = slatHeight/2.;
+       spar[2] = slatWidth/2.*1.01; 
+       Float_t dzCh4=spar[2]*1.01;
+       // zSlat to be checked (odd downstream or upstream?)
+       Float_t zSlat = (i%2 ==0)? spar[2] : -spar[2]; 
+       sprintf(volNam7,"S07%d",i);
+       gMC->Gsvolu(volNam7,"BOX",slatMaterial,spar,3);
+       gMC->Gspos(volNam7, i*4+1,"S07M", xSlat4, ySlat4, zSlat+2.*dzCh4, 0, "ONLY");
+       gMC->Gspos(volNam7, i*4+2,"S07M",-xSlat4, ySlat4, zSlat-2.*dzCh4, 0, "ONLY");
+       if (i>0) { 
+        gMC->Gspos(volNam7, i*4+3,"S07M", xSlat4,-ySlat4, zSlat+2.*dzCh4, 0, "ONLY");
+        gMC->Gspos(volNam7, i*4+4,"S07M",-xSlat4,-ySlat4, zSlat-2.*dzCh4, 0, "ONLY");
+       }
+       sprintf(volNam8,"S08%d",i);
+       gMC->Gsvolu(volNam8,"BOX",slatMaterial,spar,3);
+       gMC->Gspos(volNam8, i*4+1,"S08M", xSlat4, ySlat4, zSlat+2.*dzCh4, 0, "ONLY");
+       gMC->Gspos(volNam8, i*4+2,"S08M",-xSlat4, ySlat4, zSlat-2.*dzCh4, 0, "ONLY");
+       if (i>0) { 
+        gMC->Gspos(volNam8, i*4+3,"S08M", xSlat4,-ySlat4, zSlat+2.*dzCh4, 0, "ONLY");
+        gMC->Gspos(volNam8, i*4+4,"S08M",-xSlat4,-ySlat4, zSlat-2.*dzCh4, 0, "ONLY");
+       }
      }
+     
 
-     // create the sensitive volumes (subdivided as the PCBs),
+     // create the panel volume 
  
-     gMC->Gsvolu("S07G","BOX",sensMaterial,sensPar,3);
-     gMC->Gsvolu("S08G","BOX",sensMaterial,sensPar,3);
+     gMC->Gsvolu("S07C","BOX",panelMaterial,panelpar,3);
+     gMC->Gsvolu("S08C","BOX",panelMaterial,panelpar,3);
 
-     // create the PCB volume 
+     // create the rohacell volume 
+
+     gMC->Gsvolu("S07R","BOX",rohaMaterial,rohapar,3);
+     gMC->Gsvolu("S08R","BOX",rohaMaterial,rohapar,3);
 
-     gMC->Gsvolu("S07P","BOX",pcbMaterial,pcbpar,3);
-     gMC->Gsvolu("S08P","BOX",pcbMaterial,pcbpar,3);
      // create the insulating material volume 
 
      gMC->Gsvolu("S07I","BOX",insuMaterial,insupar,3);
      gMC->Gsvolu("S08I","BOX",insuMaterial,insupar,3);
 
-     // create the panel volume 
-
-     gMC->Gsvolu("S07C","BOX",panelMaterial,panelpar,3);
-     gMC->Gsvolu("S08C","BOX",panelMaterial,panelpar,3);
+     // create the PCB volume 
 
-     // create the rohacell volume 
+     gMC->Gsvolu("S07P","BOX",pcbMaterial,pcbpar,3);
+     gMC->Gsvolu("S08P","BOX",pcbMaterial,pcbpar,3);
  
-     gMC->Gsvolu("S07R","BOX",rohaMaterial,rohapar,3);
-     gMC->Gsvolu("S08R","BOX",rohaMaterial,rohapar,3);
+     // create the sensitive volumes,
+
+     gMC->Gsvolu("S07G","BOX",sensMaterial,dum,0);
+     gMC->Gsvolu("S08G","BOX",sensMaterial,dum,0);
 
      // create the vertical frame volume 
 
@@ -815,68 +1051,61 @@ void AliMUONv1::CreateGeometry()
 
      gMC->Gsvolu("S07B","BOX",bFrameMaterial,bFramepar,3);
      gMC->Gsvolu("S08B","BOX",bFrameMaterial,bFramepar,3);
+
+     index=0; 
      for (i = 0; i<nSlats4; i++){
        sprintf(volNam7,"S07%d",i);
        sprintf(volNam8,"S08%d",i);
        Float_t xvFrame  = (slatLength4[i] - vFrameLength)/2.;
-       gMC->Gspos("S07V",2*i-1,volNam7, xvFrame, 0., 0. , 0, "ONLY");
-       gMC->Gspos("S07V",2*i  ,volNam7,-xvFrame, 0., 0. , 0, "ONLY");
-       gMC->Gspos("S08V",2*i-1,volNam8, xvFrame, 0., 0. , 0, "ONLY");
-       gMC->Gspos("S08V",2*i  ,volNam8,-xvFrame, 0., 0. , 0, "ONLY");
+       // position the vertical frames 
+       if (i!=1 && i!=0) { 
+        gMC->Gspos("S07V",2*i-1,volNam7, xvFrame, 0., 0. , 0, "ONLY");
+        gMC->Gspos("S07V",2*i  ,volNam7,-xvFrame, 0., 0. , 0, "ONLY");
+        gMC->Gspos("S08V",2*i-1,volNam8, xvFrame, 0., 0. , 0, "ONLY");
+        gMC->Gspos("S08V",2*i  ,volNam8,-xvFrame, 0., 0. , 0, "ONLY");
+       }
+       // position the panels and the insulating material 
        for (j=0; j<nPCB4[i]; j++){
         index++;
         Float_t xx = sensLength * (-nPCB4[i]/2.+j+.5); 
-        Float_t yy = 0.;
-        Float_t zSens = 0.;  
-        gMC->Gspos("S07G",index,volNam7, xx, yy, zSens , 0, "ONLY");
-        gMC->Gspos("S08G",index,volNam8, xx, yy, zSens , 0, "ONLY");
-        Float_t zPCB = (sensWidth+pcbWidth)/2.; 
-        gMC->Gspos("S07P",2*index-1,volNam7, xx, yy, zPCB , 0, "ONLY");
-        gMC->Gspos("S07P",2*index  ,volNam7, xx, yy,-zPCB , 0, "ONLY");
-        gMC->Gspos("S08P",2*index-1,volNam8, xx, yy, zPCB , 0, "ONLY");
-        gMC->Gspos("S08P",2*index  ,volNam8, xx, yy,-zPCB , 0, "ONLY");
-        Float_t zInsu = (insuWidth+pcbWidth)/2. + zPCB; 
-        gMC->Gspos("S07I",2*index-1,volNam7, xx, yy, zInsu , 0, "ONLY");
-        gMC->Gspos("S07I",2*index  ,volNam7, xx, yy,-zInsu , 0, "ONLY");
-        gMC->Gspos("S08I",2*index-1,volNam8, xx, yy, zInsu , 0, "ONLY");
-        gMC->Gspos("S08I",2*index  ,volNam8, xx, yy,-zInsu , 0, "ONLY");
-        Float_t zPanel1 = (insuWidth+panelWidth)/2. + zInsu; 
-        gMC->Gspos("S07C",4*index-3,volNam7, xx, yy, zPanel1 , 0, "ONLY");
-        gMC->Gspos("S07C",4*index-2,volNam7, xx, yy,-zPanel1 , 0, "ONLY");
-        gMC->Gspos("S08C",4*index-3,volNam8, xx, yy, zPanel1 , 0, "ONLY");
-        gMC->Gspos("S08C",4*index-2,volNam8, xx, yy,-zPanel1 , 0, "ONLY");
-        Float_t zRoha = (rohaWidth+panelWidth)/2. + zPanel1; 
-        gMC->Gspos("S07R",2*index-1,volNam7, xx, yy, zRoha , 0, "ONLY");
-        gMC->Gspos("S07R",2*index  ,volNam7, xx, yy,-zRoha , 0, "ONLY");
-        gMC->Gspos("S08R",2*index-1,volNam8, xx, yy, zRoha , 0, "ONLY");
-        gMC->Gspos("S08R",2*index  ,volNam8, xx, yy,-zRoha , 0, "ONLY");
-        Float_t zPanel2 = (rohaWidth+panelWidth)/2. + zRoha; 
-        gMC->Gspos("S07C",4*index-1,volNam7, xx, yy, zPanel2 , 0, "ONLY");
-        gMC->Gspos("S07C",4*index  ,volNam7, xx, yy,-zPanel2 , 0, "ONLY");
-        gMC->Gspos("S08C",4*index-1,volNam8, xx, yy, zPanel2 , 0, "ONLY");
-        gMC->Gspos("S08C",4*index  ,volNam8, xx, yy,-zPanel2 , 0, "ONLY");
-        Float_t yframe = (sensHeight + hFrameHeight)/2.;
-        gMC->Gspos("S07H",2*index-1,volNam7, xx, yframe, 0. , 0, "ONLY");
-        gMC->Gspos("S07H",2*index  ,volNam7, xx,-yframe, 0. , 0, "ONLY");
-        gMC->Gspos("S08H",2*index-1,volNam8, xx, yframe, 0. , 0, "ONLY");
-        gMC->Gspos("S08H",2*index  ,volNam8, xx,-yframe, 0. , 0, "ONLY");
-        Float_t yborder = (bFrameHeight + hFrameHeight)/2. + yframe;
-        gMC->Gspos("S07B",2*index-1,volNam7, xx, yborder, 0. , 0, "ONLY");
-        gMC->Gspos("S07B",2*index  ,volNam7, xx,-yborder, 0. , 0, "ONLY");
-        gMC->Gspos("S08B",2*index-1,volNam8, xx, yborder, 0. , 0, "ONLY");
-        gMC->Gspos("S08B",2*index  ,volNam8, xx,-yborder, 0. , 0, "ONLY");
+
+        Float_t zPanel = spar[2] - panelpar[2]; 
+        gMC->Gspos("S07C",2*index-1,volNam7, xx, 0., zPanel , 0, "ONLY");
+        gMC->Gspos("S07C",2*index  ,volNam7, xx, 0.,-zPanel , 0, "ONLY");
+        gMC->Gspos("S08C",2*index-1,volNam8, xx, 0., zPanel , 0, "ONLY");
+        gMC->Gspos("S08C",2*index  ,volNam8, xx, 0.,-zPanel , 0, "ONLY");
+
+        gMC->Gspos("S07I",index,volNam7, xx, 0., 0 , 0, "ONLY");
+        gMC->Gspos("S08I",index,volNam8, xx, 0., 0 , 0, "ONLY");
        } 
      }
 
+     // position the rohacell volume inside the panel volume
+     gMC->Gspos("S07R",1,"S07C",0.,0.,0.,0,"ONLY"); 
+     gMC->Gspos("S08R",1,"S08C",0.,0.,0.,0,"ONLY"); 
+
+     // position the PCB volume inside the insulating material volume
+     gMC->Gspos("S07P",1,"S07I",0.,0.,0.,0,"ONLY"); 
+     gMC->Gspos("S08P",1,"S08I",0.,0.,0.,0,"ONLY"); 
+     // position the horizontal frame volume inside the PCB volume
+     gMC->Gspos("S07H",1,"S07P",0.,0.,0.,0,"ONLY"); 
+     gMC->Gspos("S08H",1,"S08P",0.,0.,0.,0,"ONLY"); 
+     // position the sensitive volume inside the horizontal frame volume
+     gMC->Gsposp("S07G",1,"S07H",0.,0.,0.,0,"ONLY",senspar,3); 
+     gMC->Gsposp("S08G",1,"S08H",0.,0.,0.,0,"ONLY",senspar,3); 
+     // position the border volumes inside the PCB volume
+     Float_t yborder = ( pcbHeight - bFrameHeight ) / 2.; 
+     gMC->Gspos("S07B",1,"S07P",0., yborder,0.,0,"ONLY"); 
+     gMC->Gspos("S07B",2,"S07P",0.,-yborder,0.,0,"ONLY"); 
+     gMC->Gspos("S08B",1,"S08P",0., yborder,0.,0,"ONLY"); 
+     gMC->Gspos("S08B",2,"S08P",0.,-yborder,0.,0,"ONLY"); 
+
      // create the NULOC volume and position it in the horizontal frame
+
      gMC->Gsvolu("S07N","BOX",nulocMaterial,nulocpar,3);
      gMC->Gsvolu("S08N","BOX",nulocMaterial,nulocpar,3);
-
-
-     index = 0; 
-     for (xx = -xxmax; xx<=xxmax; xx+=3*nulocLength) { 
+     index = 0;
+     for (xx = -xxmax; xx<=xxmax; xx+=2*nulocLength) { 
        index++; 
        gMC->Gspos("S07N",2*index-1,"S07B", xx, 0.,-bFrameWidth/4., 0, "ONLY");
        gMC->Gspos("S07N",2*index  ,"S07B", xx, 0., bFrameWidth/4., 0, "ONLY");
@@ -884,24 +1113,44 @@ void AliMUONv1::CreateGeometry()
        gMC->Gspos("S08N",2*index  ,"S08B", xx, 0., bFrameWidth/4., 0, "ONLY");
      }
 
-     // create the gassiplex volume 
+     // position the volumes approximating the circular section of the pipe
+     Float_t yoffs = sensHeight/2. - yOverlap; 
+     Float_t epsilon = 0.001; 
+     Int_t ndiv=6;
+     Float_t divpar[3];
+     Double_t dydiv= sensHeight/ndiv;
+     Double_t ydiv = yoffs -dydiv;
+     Int_t imax=0; 
+     imax = 1; 
+     Float_t rmin = 40.; 
+     Float_t z1 = -spar[2], z2=2*spar[2]*1.01; 
+     for (Int_t idiv=0;idiv<ndiv; idiv++){ 
+       ydiv+= dydiv;
+       Float_t xdiv = 0.; 
+       if (ydiv<rmin) xdiv= rmin * TMath::Sin( TMath::ACos(ydiv/rmin) );
+       divpar[0] = (pcbLength-xdiv)/2.; 
+       divpar[1] = dydiv/2. - epsilon;
+       divpar[2] = sensWidth/2.; 
+       Float_t xvol=(pcbLength+xdiv)/2.+1.999;
+       Float_t yvol=ydiv + dydiv/2.;
+       gMC->Gsposp("S07G",imax+4*idiv+1,"S07M", xvol, yvol, z1+z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S08G",imax+4*idiv+1,"S08M", xvol, yvol, z1+z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S07G",imax+4*idiv+2,"S07M", xvol,-yvol, z1+z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S08G",imax+4*idiv+2,"S08M", xvol,-yvol, z1+z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S07G",imax+4*idiv+3,"S07M",-xvol, yvol, z1-z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S08G",imax+4*idiv+3,"S08M",-xvol, yvol, z1-z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S07G",imax+4*idiv+4,"S07M",-xvol,-yvol, z1-z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S08G",imax+4*idiv+4,"S08M",-xvol,-yvol, z1-z2, 0, "ONLY",divpar,3);
+     }
 
-     gMC->Gsvolu("S07E","BOX",gassiMaterial,gassipar,3);
-     gMC->Gsvolu("S08E","BOX",gassiMaterial,gassipar,3);
 
 
-     // position 4 gassiplex in the nuloc
 
-     gMC->Gspos("S07E",1,"S07N", 0., -3 * nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S07E",2,"S07N", 0.,    - nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S07E",3,"S07N", 0.,      nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S07E",4,"S07N", 0.,  3 * nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S08E",1,"S08N", 0., -3 * nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S08E",2,"S08N", 0.,    - nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S08E",3,"S08N", 0.,      nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S08E",4,"S08N", 0.,  3 * nulocHeight/8., 0. , 0, "ONLY");
 
+ }
 
+ if (stations[4]) {
+     
 
 //********************************************************************
 //                            Station 5                             **
@@ -914,93 +1163,90 @@ void AliMUONv1::CreateGeometry()
      zpos1=iChamber1->Z(); 
      zpos2=iChamber2->Z();
      dstation = zpos2 - zpos1;
-     zfpos=-(iChamber->DGas()+dframez+iChamber->DAlu())/2;
+//      zfpos=-(iChamber->DGas()+dframez+iChamber->DAlu())/2; // not used any more
      
 //
 //   Mother volume
      tpar[0] = iChamber->RInner()-dframep; 
      tpar[1] = (iChamber->ROuter()+dframep)/TMath::Cos(phi);
-     tpar[2] = dstation/4;
+     tpar[2] = dstation/5.;
 
-     gMC->Gsvolu("C09M", "TUBE", idAir, tpar, 3);
-     gMC->Gsvolu("C10M", "TUBE", idAir, tpar, 3);
-     gMC->Gspos("C09M", 1, "ALIC", 0., 0., zpos1 , 0, "ONLY");
-     gMC->Gspos("C10M", 1, "ALIC", 0., 0., zpos2 , 0, "ONLY");
+     gMC->Gsvolu("S09M", "TUBE", idAir, tpar, 3);
+     gMC->Gsvolu("S10M", "TUBE", idAir, tpar, 3);
+     gMC->Gspos("S09M", 1, "ALIC", 0., 0., zpos1 , 0, "ONLY");
+     gMC->Gspos("S10M", 1, "ALIC", 0., 0., zpos2 , 0, "ONLY");
 
 
      const Int_t nSlats5 = 7;  // number of slats per quadrant
-     const Int_t nPCB5[nSlats5] = {6,6,6,5,5,4,3}; // n PCB per slat
-
-     // slat dimensions: slat is a MOTHER volume!!! made of air
+     const Int_t nPCB5[nSlats5] = {5,5,6,6,5,4,3}; // n PCB per slat
+     const Float_t xpos5[nSlats5] = {38.5, 40., 0., 0., 0., 0., 0.};
      Float_t slatLength5[nSlats5]; 
-//const Float_t slatHeight = pcbHeight; 
-//   const Float_t slatWidth = sensWidth + 2.*(pcbWidth + insuWidth + 
-// 2.* panelWidth + rohaWidth);
-//   const Int_t slatMaterial = idAir;
-//   const Float_t dSlatLength = vFrameLength; // border on left and right 
-
-     // create and position the slat (mother) volumes 
-//   Float_t spar[3];
      char volNam9[5];
      char volNam10[5];
-     Float_t xSlat5[nSlats5];
-     Float_t ySlat5[nSlats5];
+     Float_t xSlat5;
+     Float_t ySlat5;
 
      for (i = 0; i<nSlats5; i++){
        slatLength5[i] = pcbLength * nPCB5[i] + 2. * dSlatLength; 
-       xSlat5[i] = slatLength5[i]/2.; 
-       ySlat5[i] = sensHeight * (i+0.5) - yOverlap * i; 
+       xSlat5 = slatLength5[i]/2. - vFrameLength/2. +xpos5[i]; 
+       if (i==1 || i==0) slatLength5[i] -=  2. *dSlatLength; // frame out in PCB with circular border 
+       ySlat5 = sensHeight * i - yOverlap * i; 
        spar[0] = slatLength5[i]/2.; 
        spar[1] = slatHeight/2.;
-       spar[2] = slatWidth/2.; 
+       spar[2] = slatWidth/2. * 1.01; 
+       Float_t dzCh5=spar[2]*1.01;
        // zSlat to be checked (odd downstream or upstream?)
-       Float_t zSlat = (i%2 ==0)? -slatWidth/2. : slatWidth/2.
+       Float_t zSlat = (i%2 ==0)? -spar[2] : spar[2]
        sprintf(volNam9,"S09%d",i);
        gMC->Gsvolu(volNam9,"BOX",slatMaterial,spar,3);
-       gMC->Gspos(volNam9, i*4+1,"C09M", xSlat5[i], ySlat5[i], zSlat, 0, "ONLY");
-       gMC->Gspos(volNam9, i*4+2,"C09M",-xSlat5[i], ySlat5[i], zSlat, 0, "ONLY");
-       gMC->Gspos(volNam9, i*4+3,"C09M", xSlat5[i],-ySlat5[i],-zSlat, 0, "ONLY");
-       gMC->Gspos(volNam9, i*4+4,"C09M",-xSlat5[i],-ySlat5[i],-zSlat, 0, "ONLY");
+       gMC->Gspos(volNam9, i*4+1,"S09M", xSlat5, ySlat5, zSlat+2.*dzCh5, 0, "ONLY");
+       gMC->Gspos(volNam9, i*4+2,"S09M",-xSlat5, ySlat5, zSlat-2.*dzCh5, 0, "ONLY");
+       if (i>0) { 
+          gMC->Gspos(volNam9, i*4+3,"S09M", xSlat5,-ySlat5, zSlat+2.*dzCh5, 0, "ONLY");
+          gMC->Gspos(volNam9, i*4+4,"S09M",-xSlat5,-ySlat5, zSlat-2.*dzCh5, 0, "ONLY");
+       }
        sprintf(volNam10,"S10%d",i);
        gMC->Gsvolu(volNam10,"BOX",slatMaterial,spar,3);
-       gMC->Gspos(volNam10, i*4+1,"C10M", xSlat5[i], ySlat5[i], zSlat, 0, "ONLY");
-       gMC->Gspos(volNam10, i*4+2,"C10M",-xSlat5[i], ySlat5[i], zSlat, 0, "ONLY");
-       gMC->Gspos(volNam10, i*4+3,"C10M", xSlat5[i],-ySlat5[i],-zSlat, 0, "ONLY");
-       gMC->Gspos(volNam10, i*4+4,"C10M",-xSlat5[i],-ySlat5[i],-zSlat, 0, "ONLY");
+       gMC->Gspos(volNam10, i*4+1,"S10M", xSlat5, ySlat5, zSlat+2.*dzCh5, 0, "ONLY");
+       gMC->Gspos(volNam10, i*4+2,"S10M",-xSlat5, ySlat5, zSlat-2.*dzCh5, 0, "ONLY");
+       if (i>0) { 
+          gMC->Gspos(volNam10, i*4+3,"S10M", xSlat5,-ySlat5, zSlat+2.*dzCh5, 0, "ONLY");
+          gMC->Gspos(volNam10, i*4+4,"S10M",-xSlat5,-ySlat5, zSlat-2.*dzCh5, 0, "ONLY");
+       }
      }
 
-     // create the sensitive volumes (subdivided as the PCBs),
-      
-     gMC->Gsvolu("S09G","BOX",sensMaterial,sensPar,3);
-     gMC->Gsvolu("S10G","BOX",sensMaterial,sensPar,3);
-
-     // create the PCB volume 
-      
-     gMC->Gsvolu("S09P","BOX",pcbMaterial,pcbpar,3);
-     gMC->Gsvolu("S10P","BOX",pcbMaterial,pcbpar,3);
-     // create the insulating material volume 
-     
-     gMC->Gsvolu("S09I","BOX",insuMaterial,insupar,3);
-     gMC->Gsvolu("S10I","BOX",insuMaterial,insupar,3);
-
      // create the panel volume 
-  
      gMC->Gsvolu("S09C","BOX",panelMaterial,panelpar,3);
      gMC->Gsvolu("S10C","BOX",panelMaterial,panelpar,3);
 
      // create the rohacell volume 
-      
+
      gMC->Gsvolu("S09R","BOX",rohaMaterial,rohapar,3);
      gMC->Gsvolu("S10R","BOX",rohaMaterial,rohapar,3);
 
+     // create the insulating material volume 
+
+     gMC->Gsvolu("S09I","BOX",insuMaterial,insupar,3);
+     gMC->Gsvolu("S10I","BOX",insuMaterial,insupar,3);
+
+     // create the PCB volume 
+
+     gMC->Gsvolu("S09P","BOX",pcbMaterial,pcbpar,3);
+     gMC->Gsvolu("S10P","BOX",pcbMaterial,pcbpar,3);
+     // create the sensitive volumes,
+
+     gMC->Gsvolu("S09G","BOX",sensMaterial,dum,0);
+     gMC->Gsvolu("S10G","BOX",sensMaterial,dum,0);
+
      // create the vertical frame volume 
-   
+
      gMC->Gsvolu("S09V","BOX",vFrameMaterial,vFramepar,3);
      gMC->Gsvolu("S10V","BOX",vFrameMaterial,vFramepar,3);
 
      // create the horizontal frame volume 
-  
+
      gMC->Gsvolu("S09H","BOX",hFrameMaterial,hFramepar,3);
      gMC->Gsvolu("S10H","BOX",hFrameMaterial,hFramepar,3);
 
@@ -1009,91 +1255,100 @@ void AliMUONv1::CreateGeometry()
      gMC->Gsvolu("S09B","BOX",bFrameMaterial,bFramepar,3);
      gMC->Gsvolu("S10B","BOX",bFrameMaterial,bFramepar,3);
 
-     
+     index=0; 
      for (i = 0; i<nSlats5; i++){
        sprintf(volNam9,"S09%d",i);
        sprintf(volNam10,"S10%d",i);
        Float_t xvFrame  = (slatLength5[i] - vFrameLength)/2.;
-       gMC->Gspos("S09V",2*i-1,volNam9, xvFrame, 0., 0. , 0, "ONLY");
-       gMC->Gspos("S09V",2*i  ,volNam9,-xvFrame, 0., 0. , 0, "ONLY");
-       gMC->Gspos("S10V",2*i-1,volNam10, xvFrame, 0., 0. , 0, "ONLY");
-       gMC->Gspos("S10V",2*i  ,volNam10,-xvFrame, 0., 0. , 0, "ONLY");
+       // position the vertical frames 
+       if (i!=1 && i!=0) { 
+        gMC->Gspos("S09V",2*i-1,volNam9, xvFrame, 0., 0. , 0, "ONLY");
+        gMC->Gspos("S09V",2*i  ,volNam9,-xvFrame, 0., 0. , 0, "ONLY");
+        gMC->Gspos("S10V",2*i-1,volNam10, xvFrame, 0., 0. , 0, "ONLY");
+        gMC->Gspos("S10V",2*i  ,volNam10,-xvFrame, 0., 0. , 0, "ONLY");
+       }
+       
+       // position the panels and the insulating material 
        for (j=0; j<nPCB5[i]; j++){
         index++;
         Float_t xx = sensLength * (-nPCB5[i]/2.+j+.5); 
-        Float_t yy = 0.;
-        Float_t zSens = 0.;  
-        gMC->Gspos("S09G",index,volNam9, xx, yy, zSens , 0, "ONLY");
-        gMC->Gspos("S10G",index,volNam10, xx, yy, zSens , 0, "ONLY");
-        Float_t zPCB = (sensWidth+pcbWidth)/2.; 
-        gMC->Gspos("S09P",2*index-1,volNam9, xx, yy, zPCB , 0, "ONLY");
-        gMC->Gspos("S09P",2*index  ,volNam9, xx, yy,-zPCB , 0, "ONLY");
-        gMC->Gspos("S10P",2*index-1,volNam10, xx, yy, zPCB , 0, "ONLY");
-        gMC->Gspos("S10P",2*index  ,volNam10, xx, yy,-zPCB , 0, "ONLY");
-        Float_t zInsu = (insuWidth+pcbWidth)/2. + zPCB; 
-        gMC->Gspos("S09I",2*index-1,volNam9, xx, yy, zInsu , 0, "ONLY");
-        gMC->Gspos("S09I",2*index  ,volNam9, xx, yy,-zInsu , 0, "ONLY");
-        gMC->Gspos("S10I",2*index-1,volNam10, xx, yy, zInsu , 0, "ONLY");
-        gMC->Gspos("S10I",2*index  ,volNam10, xx, yy,-zInsu , 0, "ONLY");
-        Float_t zPanel1 = (insuWidth+panelWidth)/2. + zInsu; 
-        gMC->Gspos("S09C",4*index-3,volNam9, xx, yy, zPanel1 , 0, "ONLY");
-        gMC->Gspos("S09C",4*index-2,volNam9, xx, yy,-zPanel1 , 0, "ONLY");
-        gMC->Gspos("S10C",4*index-3,volNam10, xx, yy, zPanel1 , 0, "ONLY");
-        gMC->Gspos("S10C",4*index-2,volNam10, xx, yy,-zPanel1 , 0, "ONLY");
-        Float_t zRoha = (rohaWidth+panelWidth)/2. + zPanel1; 
-        gMC->Gspos("S09R",2*index-1,volNam9, xx, yy, zRoha , 0, "ONLY");
-        gMC->Gspos("S09R",2*index  ,volNam9, xx, yy,-zRoha , 0, "ONLY");
-        gMC->Gspos("S10R",2*index-1,volNam10, xx, yy, zRoha , 0, "ONLY");
-        gMC->Gspos("S10R",2*index  ,volNam10, xx, yy,-zRoha , 0, "ONLY");
-        Float_t zPanel2 = (rohaWidth+panelWidth)/2. + zRoha; 
-        gMC->Gspos("S09C",4*index-1,volNam9, xx, yy, zPanel2 , 0, "ONLY");
-        gMC->Gspos("S09C",4*index  ,volNam9, xx, yy,-zPanel2 , 0, "ONLY");
-        gMC->Gspos("S10C",4*index-1,volNam10, xx, yy, zPanel2 , 0, "ONLY");
-        gMC->Gspos("S10C",4*index  ,volNam10, xx, yy,-zPanel2 , 0, "ONLY");
-        Float_t yframe = (sensHeight + hFrameHeight)/2.;
-        gMC->Gspos("S09H",2*index-1,volNam9, xx, yframe, 0. , 0, "ONLY");
-        gMC->Gspos("S09H",2*index  ,volNam9, xx,-yframe, 0. , 0, "ONLY");
-        gMC->Gspos("S10H",2*index-1,volNam10, xx, yframe, 0. , 0, "ONLY");
-        gMC->Gspos("S10H",2*index  ,volNam10, xx,-yframe, 0. , 0, "ONLY");
-        Float_t yborder = (bFrameHeight + hFrameHeight)/2. + yframe;
-        gMC->Gspos("S09B",2*index-1,volNam9, xx, yborder, 0. , 0, "ONLY");
-        gMC->Gspos("S09B",2*index  ,volNam9, xx,-yborder, 0. , 0, "ONLY");
-        gMC->Gspos("S10B",2*index-1,volNam10, xx, yborder, 0. , 0, "ONLY");
-        gMC->Gspos("S10B",2*index  ,volNam10, xx,-yborder, 0. , 0, "ONLY");
+
+        Float_t zPanel = spar[2] - panelpar[2]; 
+        gMC->Gspos("S09C",2*index-1,volNam9, xx, 0., zPanel , 0, "ONLY");
+        gMC->Gspos("S09C",2*index  ,volNam9, xx, 0.,-zPanel , 0, "ONLY");
+        gMC->Gspos("S10C",2*index-1,volNam10, xx, 0., zPanel , 0, "ONLY");
+        gMC->Gspos("S10C",2*index  ,volNam10, xx, 0.,-zPanel , 0, "ONLY");
+
+        gMC->Gspos("S09I",index,volNam9, xx, 0., 0 , 0, "ONLY");
+        gMC->Gspos("S10I",index,volNam10, xx, 0., 0 , 0, "ONLY");
        } 
      }
 
+     // position the rohacell volume inside the panel volume
+     gMC->Gspos("S09R",1,"S09C",0.,0.,0.,0,"ONLY"); 
+     gMC->Gspos("S10R",1,"S10C",0.,0.,0.,0,"ONLY"); 
+
+     // position the PCB volume inside the insulating material volume
+     gMC->Gspos("S09P",1,"S09I",0.,0.,0.,0,"ONLY"); 
+     gMC->Gspos("S10P",1,"S10I",0.,0.,0.,0,"ONLY"); 
+     // position the horizontal frame volume inside the PCB volume
+     gMC->Gspos("S09H",1,"S09P",0.,0.,0.,0,"ONLY"); 
+     gMC->Gspos("S10H",1,"S10P",0.,0.,0.,0,"ONLY"); 
+     // position the sensitive volume inside the horizontal frame volume
+     gMC->Gsposp("S09G",1,"S09H",0.,0.,0.,0,"ONLY",senspar,3); 
+     gMC->Gsposp("S10G",1,"S10H",0.,0.,0.,0,"ONLY",senspar,3); 
+     // position the border volumes inside the PCB volume
+     Float_t yborder = ( pcbHeight - bFrameHeight ) / 2.; 
+     gMC->Gspos("S09B",1,"S09P",0., yborder,0.,0,"ONLY"); 
+     gMC->Gspos("S09B",2,"S09P",0.,-yborder,0.,0,"ONLY"); 
+     gMC->Gspos("S10B",1,"S10P",0., yborder,0.,0,"ONLY"); 
+     gMC->Gspos("S10B",2,"S10P",0.,-yborder,0.,0,"ONLY"); 
+
      // create the NULOC volume and position it in the horizontal frame
-     
+
      gMC->Gsvolu("S09N","BOX",nulocMaterial,nulocpar,3);
      gMC->Gsvolu("S10N","BOX",nulocMaterial,nulocpar,3);
-     index = 0; 
-     for (xx = -xxmax; xx<=xxmax; xx+=3*nulocLength) { 
+     index = 0;
+     for (xx = -xxmax; xx<=xxmax; xx+=2*nulocLength) { 
        index++; 
        gMC->Gspos("S09N",2*index-1,"S09B", xx, 0.,-bFrameWidth/4., 0, "ONLY");
        gMC->Gspos("S09N",2*index  ,"S09B", xx, 0., bFrameWidth/4., 0, "ONLY");
        gMC->Gspos("S10N",2*index-1,"S10B", xx, 0.,-bFrameWidth/4., 0, "ONLY");
        gMC->Gspos("S10N",2*index  ,"S10B", xx, 0., bFrameWidth/4., 0, "ONLY");
      }
+     // position the volumes approximating the circular section of the pipe
+     Float_t yoffs = sensHeight/2. - yOverlap; 
+     Float_t epsilon = 0.001; 
+     Int_t ndiv=6;
+     Float_t divpar[3];
+     Double_t dydiv= sensHeight/ndiv;
+     Double_t ydiv = yoffs -dydiv;
+     Int_t imax=0; 
+     //     for (Int_t islat=0; islat<nSlats3; islat++) imax += nPCB3[islat]; 
+     imax = 1; 
+     Float_t rmin = 40.; 
+     Float_t z1 = spar[2], z2=2*spar[2]*1.01; 
+     for (Int_t idiv=0;idiv<ndiv; idiv++){ 
+       ydiv+= dydiv;
+       Float_t xdiv = 0.; 
+       if (ydiv<rmin) xdiv= rmin * TMath::Sin( TMath::ACos(ydiv/rmin) );
+       divpar[0] = (pcbLength-xdiv)/2.; 
+       divpar[1] = dydiv/2. - epsilon;
+       divpar[2] = sensWidth/2.; 
+       Float_t xvol=(pcbLength+xdiv)/2. + 1.999;
+       Float_t yvol=ydiv + dydiv/2.;
+       gMC->Gsposp("S09G",imax+4*idiv+1,"S09M", xvol, yvol, z1+z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S10G",imax+4*idiv+1,"S10M", xvol, yvol, z1+z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S09G",imax+4*idiv+2,"S09M", xvol,-yvol, z1+z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S10G",imax+4*idiv+2,"S10M", xvol,-yvol, z1+z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S09G",imax+4*idiv+3,"S09M",-xvol, yvol, z1-z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S10G",imax+4*idiv+3,"S10M",-xvol, yvol, z1-z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S09G",imax+4*idiv+4,"S09M",-xvol,-yvol, z1-z2, 0, "ONLY",divpar,3);
+       gMC->Gsposp("S10G",imax+4*idiv+4,"S10M",-xvol,-yvol, z1-z2, 0, "ONLY",divpar,3);
+     }
 
-     // create the gassiplex volume 
-     
-     gMC->Gsvolu("S09E","BOX",gassiMaterial,gassipar,3);
-     gMC->Gsvolu("S10E","BOX",gassiMaterial,gassipar,3);
-
-
-     // position 4 gassiplex in the nuloc
-
-     gMC->Gspos("S09E",1,"S09N", 0., -3 * nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S09E",2,"S09N", 0.,    - nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S09E",3,"S09N", 0.,      nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S09E",4,"S09N", 0.,  3 * nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S10E",1,"S10N", 0., -3 * nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S10E",2,"S10N", 0.,    - nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S10E",3,"S10N", 0.,      nulocHeight/8., 0. , 0, "ONLY");
-     gMC->Gspos("S10E",4,"S10N", 0.,  3 * nulocHeight/8., 0. , 0, "ONLY");
-
+ }
 
 ///////////////////////////////////////
 // GEOMETRY FOR THE TRIGGER CHAMBERS //
@@ -1106,16 +1361,19 @@ void AliMUONv1::CreateGeometry()
 
 //  Parameters of the Trigger Chambers
 
-               
+// DP03-01 introduce dead zone of +/- 2 cm arround x=0 (as in TDR, fig3.27)                    
+     const Float_t kDXZERO=2.; 
      const Float_t kXMC1MIN=34.;       
      const Float_t kXMC1MED=51.;                                
      const Float_t kXMC1MAX=272.;                               
      const Float_t kYMC1MIN=34.;                              
      const Float_t kYMC1MAX=51.;                              
      const Float_t kRMIN1=50.;
-     const Float_t kRMAX1=62.;
+// DP03-01     const Float_t kRMAX1=62.;
+     const Float_t kRMAX1=64.;
      const Float_t kRMIN2=50.;
-     const Float_t kRMAX2=66.;
+// DP03-01      const Float_t kRMAX2=66.;
+     const Float_t kRMAX2=68.;
 
 //   zposition of the middle of the gas gap in mother vol 
      const Float_t kZMCm=-3.6;
@@ -1149,17 +1407,17 @@ void AliMUONv1::CreateGeometry()
      tpar[0] = iChamber->RInner(); 
      tpar[1] = iChamber->ROuter();
      tpar[2] = 4.0;    
-     gMC->Gsvolu("CM11", "TUBE", idAir, tpar, 3);
-     gMC->Gsvolu("CM12", "TUBE", idAir, tpar, 3);
+     gMC->Gsvolu("SM11", "TUBE", idAir, tpar, 3);
+     gMC->Gsvolu("SM12", "TUBE", idAir, tpar, 3);
      
 // Definition of the flange between the beam shielding and the RPC 
      tpar[0]= kRMIN1;
      tpar[1]= kRMAX1;
      tpar[2]= 4.0;
    
-     gMC->Gsvolu("CF1A", "TUBE", idAlu1, tpar, 3);     //Al
-     gMC->Gspos("CF1A", 1, "CM11", 0., 0., 0., 0, "MANY");
-     gMC->Gspos("CF1A", 2, "CM12", 0., 0., 0., 0, "MANY");
+     gMC->Gsvolu("SF1A", "TUBE", idAlu1, tpar, 3);     //Al
+     gMC->Gspos("SF1A", 1, "SM11", 0., 0., 0., 0, "MANY");
+     gMC->Gspos("SF1A", 2, "SM12", 0., 0., 0., 0, "MANY");
 
 
 // FIRST PLANE OF STATION 1
@@ -1175,29 +1433,30 @@ void AliMUONv1::CreateGeometry()
      tpar[1]= 0.;
      tpar[2]= 0.;
           
-     gMC->Gsvolu("CC1A", "BOX ", idAlu1, tpar, 0);           //Al    
-     gMC->Gsvolu("CB1A", "BOX ", idtmed[1107], tpar, 0);     //Bakelite 
-     gMC->Gsvolu("CG1A", "BOX ", idtmed[1106], tpar, 0);     //Gas streamer
+     gMC->Gsvolu("SC1A", "BOX ", idAlu1, tpar, 0);           //Al    
+     gMC->Gsvolu("SB1A", "BOX ", idtmed[1107], tpar, 0);     //Bakelite 
+     gMC->Gsvolu("SG1A", "BOX ", idtmed[1106], tpar, 0);     //Gas streamer
 
 // chamber type A
      tpar[0] = -1.;
      tpar[1] = -1.;
      
-     const Float_t kXMC1A=kXMC1MED+(kXMC1MAX-kXMC1MED)/2.;
+// DP03-01     const Float_t kXMC1A=kXMC1MED+(kXMC1MAX-kXMC1MED)/2.;
+     const Float_t kXMC1A=kDXZERO+kXMC1MED+(kXMC1MAX-kXMC1MED)/2.;
      const Float_t kYMC1Am=0.;
      const Float_t kYMC1Ap=0.;
           
      tpar[2] = 0.1;    
-     gMC->Gsposp("CG1A", 1, "CB1A", 0., 0., 0., 0, "ONLY",tpar,3);
+     gMC->Gsposp("SG1A", 1, "SB1A", 0., 0., 0., 0, "ONLY",tpar,3);
      tpar[2] = 0.3;
-     gMC->Gsposp("CB1A", 1, "CC1A", 0., 0., 0., 0, "ONLY",tpar,3);
+     gMC->Gsposp("SB1A", 1, "SC1A", 0., 0., 0., 0, "ONLY",tpar,3);
 
      tpar[2] = 0.4;
      tpar[0] = (kXMC1MAX-kXMC1MED)/2.;
      tpar[1] = kYMC1MIN;
 
-     gMC->Gsposp("CC1A", 1, "CM11",kXMC1A,kYMC1Am,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 2, "CM11",-kXMC1A,kYMC1Ap,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 1, "SM11",kXMC1A,kYMC1Am,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 2, "SM11",-kXMC1A,kYMC1Ap,kZMCp, 0, "ONLY", tpar, 3);
      
 //  chamber type B    
      Float_t tpar1save=tpar[1];
@@ -1207,14 +1466,15 @@ void AliMUONv1::CreateGeometry()
      tpar[0] = (kXMC1MAX-kXMC1MIN)/2.;
      tpar[1] = (kYMC1MAX-kYMC1MIN)/2.;
      
-     const Float_t kXMC1B=kXMC1MIN+tpar[0];
+// DP03-01     const Float_t kXMC1B=kXMC1MIN+tpar[0];
+     const Float_t kXMC1B=kDXZERO+kXMC1MIN+tpar[0];
      const Float_t kYMC1Bp=(y1msave+tpar1save)*zpm+tpar[1];
      const Float_t kYMC1Bm=(y1psave+tpar1save)*zmp+tpar[1];
 
-     gMC->Gsposp("CC1A", 3, "CM11",kXMC1B,kYMC1Bp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 4, "CM11",-kXMC1B,kYMC1Bm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 5, "CM11",kXMC1B,-kYMC1Bp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 6, "CM11",-kXMC1B,-kYMC1Bm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 3, "SM11",kXMC1B,kYMC1Bp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 4, "SM11",-kXMC1B,kYMC1Bm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 5, "SM11",kXMC1B,-kYMC1Bp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 6, "SM11",-kXMC1B,-kYMC1Bm,kZMCm, 0, "ONLY", tpar, 3);
      
 //  chamber type C  (end of type B !!)      
      tpar1save=tpar[1];
@@ -1224,15 +1484,17 @@ void AliMUONv1::CreateGeometry()
      tpar[0] = kXMC1MAX/2;
      tpar[1] = kYMC1MAX/2;
      
-     const Float_t kXMC1C=tpar[0];
+
+// DP03-01     const Float_t kXMC1C=tpar[0];
+     const Float_t kXMC1C=kDXZERO+tpar[0];
 // warning : same Z than type B
      const Float_t kYMC1Cp=(y1psave+tpar1save)*1.+tpar[1];
      const Float_t kYMC1Cm=(y1msave+tpar1save)*1.+tpar[1];
      
-     gMC->Gsposp("CC1A", 7, "CM11",kXMC1C,kYMC1Cp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 8, "CM11",-kXMC1C,kYMC1Cm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 9, "CM11",kXMC1C,-kYMC1Cp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 10, "CM11",-kXMC1C,-kYMC1Cm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 7, "SM11",kXMC1C,kYMC1Cp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 8, "SM11",-kXMC1C,kYMC1Cm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 9, "SM11",kXMC1C,-kYMC1Cp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 10, "SM11",-kXMC1C,-kYMC1Cm,kZMCm, 0, "ONLY", tpar, 3);
      
 //  chamber type D, E and F (same size)        
      tpar1save=tpar[1];
@@ -1242,14 +1504,15 @@ void AliMUONv1::CreateGeometry()
      tpar[0] = kXMC1MAX/2.;
      tpar[1] = kYMC1MIN;
      
-     const Float_t kXMC1D=tpar[0];
+// DP03-01     const Float_t kXMC1D=tpar[0];
+     const Float_t kXMC1D=kDXZERO+tpar[0];
      const Float_t kYMC1Dp=(y1msave+tpar1save)*zpm+tpar[1];
      const Float_t kYMC1Dm=(y1psave+tpar1save)*zmp+tpar[1];
      
-     gMC->Gsposp("CC1A", 11, "CM11",kXMC1D,kYMC1Dm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 12, "CM11",-kXMC1D,kYMC1Dp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 13, "CM11",kXMC1D,-kYMC1Dm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 14, "CM11",-kXMC1D,-kYMC1Dp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 11, "SM11",kXMC1D,kYMC1Dm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 12, "SM11",-kXMC1D,kYMC1Dp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 13, "SM11",kXMC1D,-kYMC1Dm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 14, "SM11",-kXMC1D,-kYMC1Dp,kZMCp, 0, "ONLY", tpar, 3);
 
 
      tpar1save=tpar[1];
@@ -1258,10 +1521,10 @@ void AliMUONv1::CreateGeometry()
      const Float_t kYMC1Ep=(y1msave+tpar1save)*zpm+tpar[1];
      const Float_t kYMC1Em=(y1psave+tpar1save)*zmp+tpar[1];
      
-     gMC->Gsposp("CC1A", 15, "CM11",kXMC1D,kYMC1Ep,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 16, "CM11",-kXMC1D,kYMC1Em,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 17, "CM11",kXMC1D,-kYMC1Ep,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 18, "CM11",-kXMC1D,-kYMC1Em,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 15, "SM11",kXMC1D,kYMC1Ep,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 16, "SM11",-kXMC1D,kYMC1Em,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 17, "SM11",kXMC1D,-kYMC1Ep,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 18, "SM11",-kXMC1D,-kYMC1Em,kZMCm, 0, "ONLY", tpar, 3);
 
      tpar1save=tpar[1];
      y1msave=kYMC1Em;
@@ -1269,13 +1532,13 @@ void AliMUONv1::CreateGeometry()
      const Float_t kYMC1Fp=(y1msave+tpar1save)*zpm+tpar[1];
      const Float_t kYMC1Fm=(y1psave+tpar1save)*zmp+tpar[1];
     
-     gMC->Gsposp("CC1A", 19, "CM11",kXMC1D,kYMC1Fm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 20, "CM11",-kXMC1D,kYMC1Fp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 21, "CM11",kXMC1D,-kYMC1Fm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC1A", 22, "CM11",-kXMC1D,-kYMC1Fp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 19, "SM11",kXMC1D,kYMC1Fm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 20, "SM11",-kXMC1D,kYMC1Fp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 21, "SM11",kXMC1D,-kYMC1Fm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC1A", 22, "SM11",-kXMC1D,-kYMC1Fp,kZMCp, 0, "ONLY", tpar, 3);
 
 // Positioning first plane in ALICE     
-     gMC->Gspos("CM11", 1, "ALIC", 0., 0., zpos1, 0, "ONLY");
+     gMC->Gspos("SM11", 1, "ALIC", 0., 0., zpos1, 0, "ONLY");
 
 // End of geometry definition for the first plane of station 1
 
@@ -1291,9 +1554,9 @@ void AliMUONv1::CreateGeometry()
      tpar[1]= 0.;
      tpar[2]= 0.;
           
-     gMC->Gsvolu("CC2A", "BOX ", idAlu1, tpar, 0);           //Al    
-     gMC->Gsvolu("CB2A", "BOX ", idtmed[1107], tpar, 0);     //Bakelite 
-     gMC->Gsvolu("CG2A", "BOX ", idtmed[1106], tpar, 0);     //Gas streamer
+     gMC->Gsvolu("SC2A", "BOX ", idAlu1, tpar, 0);           //Al    
+     gMC->Gsvolu("SB2A", "BOX ", idtmed[1107], tpar, 0);     //Bakelite 
+     gMC->Gsvolu("SG2A", "BOX ", idtmed[1106], tpar, 0);     //Gas streamer
 
 // chamber type A
      tpar[0] = -1.;
@@ -1304,16 +1567,16 @@ void AliMUONv1::CreateGeometry()
      const Float_t kYMC2Ap=0.;
           
      tpar[2] = 0.1;    
-     gMC->Gsposp("CG2A", 1, "CB2A", 0., 0., 0., 0, "ONLY",tpar,3);
+     gMC->Gsposp("SG2A", 1, "SB2A", 0., 0., 0., 0, "ONLY",tpar,3);
      tpar[2] = 0.3;
-     gMC->Gsposp("CB2A", 1, "CC2A", 0., 0., 0., 0, "ONLY",tpar,3);
+     gMC->Gsposp("SB2A", 1, "SC2A", 0., 0., 0., 0, "ONLY",tpar,3);
 
      tpar[2] = 0.4;
      tpar[0] = ((kXMC1MAX-kXMC1MED)/2.)*kZ12;
      tpar[1] = kYMC1MIN*kZ12;
 
-     gMC->Gsposp("CC2A", 1, "CM12",kXMC2A,kYMC2Am,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 2, "CM12",-kXMC2A,kYMC2Ap,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 1, "SM12",kXMC2A,kYMC2Am,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 2, "SM12",-kXMC2A,kYMC2Ap,kZMCp, 0, "ONLY", tpar, 3);
      
 
 //  chamber type B    
@@ -1324,10 +1587,10 @@ void AliMUONv1::CreateGeometry()
      const Float_t kXMC2B=kXMC1B*kZ12;
      const Float_t kYMC2Bp=kYMC1Bp*kZ12;
      const Float_t kYMC2Bm=kYMC1Bm*kZ12;
-     gMC->Gsposp("CC2A", 3, "CM12",kXMC2B,kYMC2Bp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 4, "CM12",-kXMC2B,kYMC2Bm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 5, "CM12",kXMC2B,-kYMC2Bp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 6, "CM12",-kXMC2B,-kYMC2Bm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 3, "SM12",kXMC2B,kYMC2Bp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 4, "SM12",-kXMC2B,kYMC2Bm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 5, "SM12",kXMC2B,-kYMC2Bp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 6, "SM12",-kXMC2B,-kYMC2Bm,kZMCm, 0, "ONLY", tpar, 3);
 
      
 //  chamber type C   (end of type B !!)     
@@ -1338,10 +1601,10 @@ void AliMUONv1::CreateGeometry()
      const Float_t kXMC2C=kXMC1C*kZ12;
      const Float_t kYMC2Cp=kYMC1Cp*kZ12;
      const Float_t kYMC2Cm=kYMC1Cm*kZ12;     
-     gMC->Gsposp("CC2A", 7, "CM12",kXMC2C,kYMC2Cp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 8, "CM12",-kXMC2C,kYMC2Cm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 9, "CM12",kXMC2C,-kYMC2Cp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 10, "CM12",-kXMC2C,-kYMC2Cm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 7, "SM12",kXMC2C,kYMC2Cp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 8, "SM12",-kXMC2C,kYMC2Cm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 9, "SM12",kXMC2C,-kYMC2Cp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 10, "SM12",-kXMC2C,-kYMC2Cm,kZMCm, 0, "ONLY", tpar, 3);
      
 //  chamber type D, E and F (same size)        
 
@@ -1351,29 +1614,29 @@ void AliMUONv1::CreateGeometry()
      const Float_t kXMC2D=kXMC1D*kZ12;
      const Float_t kYMC2Dp=kYMC1Dp*kZ12;
      const Float_t kYMC2Dm=kYMC1Dm*kZ12;     
-     gMC->Gsposp("CC2A", 11, "CM12",kXMC2D,kYMC2Dm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 12, "CM12",-kXMC2D,kYMC2Dp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 13, "CM12",kXMC2D,-kYMC2Dm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 14, "CM12",-kXMC2D,-kYMC2Dp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 11, "SM12",kXMC2D,kYMC2Dm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 12, "SM12",-kXMC2D,kYMC2Dp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 13, "SM12",kXMC2D,-kYMC2Dm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 14, "SM12",-kXMC2D,-kYMC2Dp,kZMCp, 0, "ONLY", tpar, 3);
 
      const Float_t kYMC2Ep=kYMC1Ep*kZ12;
      const Float_t kYMC2Em=kYMC1Em*kZ12;
-     gMC->Gsposp("CC2A", 15, "CM12",kXMC2D,kYMC2Ep,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 16, "CM12",-kXMC2D,kYMC2Em,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 17, "CM12",kXMC2D,-kYMC2Ep,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 18, "CM12",-kXMC2D,-kYMC2Em,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 15, "SM12",kXMC2D,kYMC2Ep,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 16, "SM12",-kXMC2D,kYMC2Em,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 17, "SM12",kXMC2D,-kYMC2Ep,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 18, "SM12",-kXMC2D,-kYMC2Em,kZMCm, 0, "ONLY", tpar, 3);
 
 
      const Float_t kYMC2Fp=kYMC1Fp*kZ12;
      const Float_t kYMC2Fm=kYMC1Fm*kZ12;
-     gMC->Gsposp("CC2A", 19, "CM12",kXMC2D,kYMC2Fm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 20, "CM12",-kXMC2D,kYMC2Fp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 21, "CM12",kXMC2D,-kYMC2Fm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC2A", 22, "CM12",-kXMC2D,-kYMC2Fp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 19, "SM12",kXMC2D,kYMC2Fm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 20, "SM12",-kXMC2D,kYMC2Fp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 21, "SM12",kXMC2D,-kYMC2Fm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC2A", 22, "SM12",-kXMC2D,-kYMC2Fp,kZMCp, 0, "ONLY", tpar, 3);
 
 // Positioning second plane of station 1 in ALICE     
      
-     gMC->Gspos("CM12", 1, "ALIC", 0., 0., zpos2, 0, "ONLY");
+     gMC->Gspos("SM12", 1, "ALIC", 0., 0., zpos2, 0, "ONLY");
 
 // End of geometry definition for the second plane of station 1
 
@@ -1402,8 +1665,8 @@ void AliMUONv1::CreateGeometry()
      tpar[1] = iChamber->ROuter();
      tpar[2] = 4.0;    
  
-     gMC->Gsvolu("CM21", "TUBE", idAir, tpar, 3);
-     gMC->Gsvolu("CM22", "TUBE", idAir, tpar, 3);
+     gMC->Gsvolu("SM21", "TUBE", idAir, tpar, 3);
+     gMC->Gsvolu("SM22", "TUBE", idAir, tpar, 3);
      
 // Definition of the flange between the beam shielding and the RPC 
 //  ???? interface shielding
@@ -1412,9 +1675,9 @@ void AliMUONv1::CreateGeometry()
      tpar[1]= kRMAX2;
      tpar[2]= 4.0;
    
-     gMC->Gsvolu("CF2A", "TUBE", idAlu1, tpar, 3);            //Al
-     gMC->Gspos("CF2A", 1, "CM21", 0., 0., 0., 0, "MANY");
-     gMC->Gspos("CF2A", 2, "CM22", 0., 0., 0., 0, "MANY");
+     gMC->Gsvolu("SF2A", "TUBE", idAlu1, tpar, 3);            //Al
+     gMC->Gspos("SF2A", 1, "SM21", 0., 0., 0., 0, "MANY");
+     gMC->Gspos("SF2A", 2, "SM22", 0., 0., 0., 0, "MANY");
     
 
 
@@ -1427,9 +1690,9 @@ void AliMUONv1::CreateGeometry()
      tpar[1]= 0.;
      tpar[2]= 0.;
           
-     gMC->Gsvolu("CC3A", "BOX ", idAlu1, tpar, 0);           //Al  
-     gMC->Gsvolu("CB3A", "BOX ", idtmed[1107], tpar, 0);     //Bakelite 
-     gMC->Gsvolu("CG3A", "BOX ", idtmed[1106], tpar, 0);     //Gas streamer
+     gMC->Gsvolu("SC3A", "BOX ", idAlu1, tpar, 0);           //Al  
+     gMC->Gsvolu("SB3A", "BOX ", idtmed[1107], tpar, 0);     //Bakelite 
+     gMC->Gsvolu("SG3A", "BOX ", idtmed[1106], tpar, 0);     //Gas streamer
 
 
 // chamber type A
@@ -1441,15 +1704,15 @@ void AliMUONv1::CreateGeometry()
      const Float_t kYMC3Ap=0.;
           
      tpar[2] = 0.1;    
-     gMC->Gsposp("CG3A", 1, "CB3A", 0., 0., 0., 0, "ONLY",tpar,3);
+     gMC->Gsposp("SG3A", 1, "SB3A", 0., 0., 0., 0, "ONLY",tpar,3);
      tpar[2] = 0.3;
-     gMC->Gsposp("CB3A", 1, "CC3A", 0., 0., 0., 0, "ONLY",tpar,3);
+     gMC->Gsposp("SB3A", 1, "SC3A", 0., 0., 0., 0, "ONLY",tpar,3);
 
      tpar[2] = 0.4;
      tpar[0] = ((kXMC1MAX-kXMC1MED)/2.)*kZ13;
      tpar[1] = kYMC1MIN*kZ13;
-     gMC->Gsposp("CC3A", 1, "CM21",kXMC3A,kYMC3Am,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 2, "CM21",-kXMC3A,kYMC3Ap,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 1, "SM21",kXMC3A,kYMC3Am,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 2, "SM21",-kXMC3A,kYMC3Ap,kZMCp, 0, "ONLY", tpar, 3);
 
      
 //  chamber type B    
@@ -1459,10 +1722,10 @@ void AliMUONv1::CreateGeometry()
      const Float_t kXMC3B=kXMC1B*kZ13;
      const Float_t kYMC3Bp=kYMC1Bp*kZ13;
      const Float_t kYMC3Bm=kYMC1Bm*kZ13;
-     gMC->Gsposp("CC3A", 3, "CM21",kXMC3B,kYMC3Bp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 4, "CM21",-kXMC3B,kYMC3Bm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 5, "CM21",kXMC3B,-kYMC3Bp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 6, "CM21",-kXMC3B,-kYMC3Bm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 3, "SM21",kXMC3B,kYMC3Bp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 4, "SM21",-kXMC3B,kYMC3Bm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 5, "SM21",kXMC3B,-kYMC3Bp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 6, "SM21",-kXMC3B,-kYMC3Bm,kZMCm, 0, "ONLY", tpar, 3);
 
      
 //  chamber type C  (end of type B !!)      
@@ -1472,10 +1735,10 @@ void AliMUONv1::CreateGeometry()
      const Float_t kXMC3C=kXMC1C*kZ13;
      const Float_t kYMC3Cp=kYMC1Cp*kZ13;
      const Float_t kYMC3Cm=kYMC1Cm*kZ13;     
-     gMC->Gsposp("CC3A", 7, "CM21",kXMC3C,kYMC3Cp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 8, "CM21",-kXMC3C,kYMC3Cm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 9, "CM21",kXMC3C,-kYMC3Cp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 10, "CM21",-kXMC3C,-kYMC3Cm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 7, "SM21",kXMC3C,kYMC3Cp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 8, "SM21",-kXMC3C,kYMC3Cm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 9, "SM21",kXMC3C,-kYMC3Cp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 10, "SM21",-kXMC3C,-kYMC3Cm,kZMCm, 0, "ONLY", tpar, 3);
      
 
 //  chamber type D, E and F (same size)         
@@ -1486,29 +1749,29 @@ void AliMUONv1::CreateGeometry()
      const Float_t kXMC3D=kXMC1D*kZ13;
      const Float_t kYMC3Dp=kYMC1Dp*kZ13;
      const Float_t kYMC3Dm=kYMC1Dm*kZ13;          
-     gMC->Gsposp("CC3A", 11, "CM21",kXMC3D,kYMC3Dm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 12, "CM21",-kXMC3D,kYMC3Dp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 13, "CM21",kXMC3D,-kYMC3Dm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 14, "CM21",-kXMC3D,-kYMC3Dp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 11, "SM21",kXMC3D,kYMC3Dm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 12, "SM21",-kXMC3D,kYMC3Dp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 13, "SM21",kXMC3D,-kYMC3Dm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 14, "SM21",-kXMC3D,-kYMC3Dp,kZMCp, 0, "ONLY", tpar, 3);
 
      const Float_t kYMC3Ep=kYMC1Ep*kZ13;
      const Float_t kYMC3Em=kYMC1Em*kZ13;
-     gMC->Gsposp("CC3A", 15, "CM21",kXMC3D,kYMC3Ep,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 16, "CM21",-kXMC3D,kYMC3Em,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 17, "CM21",kXMC3D,-kYMC3Ep,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 18, "CM21",-kXMC3D,-kYMC3Em,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 15, "SM21",kXMC3D,kYMC3Ep,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 16, "SM21",-kXMC3D,kYMC3Em,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 17, "SM21",kXMC3D,-kYMC3Ep,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 18, "SM21",-kXMC3D,-kYMC3Em,kZMCm, 0, "ONLY", tpar, 3);
 
      const Float_t kYMC3Fp=kYMC1Fp*kZ13;
      const Float_t kYMC3Fm=kYMC1Fm*kZ13;
-     gMC->Gsposp("CC3A", 19, "CM21",kXMC3D,kYMC3Fm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 20, "CM21",-kXMC3D,kYMC3Fp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 21, "CM21",kXMC3D,-kYMC3Fm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC3A", 22, "CM21",-kXMC3D,-kYMC3Fp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 19, "SM21",kXMC3D,kYMC3Fm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 20, "SM21",-kXMC3D,kYMC3Fp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 21, "SM21",kXMC3D,-kYMC3Fm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC3A", 22, "SM21",-kXMC3D,-kYMC3Fp,kZMCp, 0, "ONLY", tpar, 3);
        
 
 // Positioning first plane of station 2 in ALICE
      
-     gMC->Gspos("CM21", 1, "ALIC", 0., 0., zpos3, 0, "ONLY");
+     gMC->Gspos("SM21", 1, "ALIC", 0., 0., zpos3, 0, "ONLY");
 
 // End of geometry definition for the first plane of station 2
 
@@ -1525,9 +1788,9 @@ void AliMUONv1::CreateGeometry()
      tpar[1]= 0.;
      tpar[2]= 0.;
           
-     gMC->Gsvolu("CC4A", "BOX ", idAlu1, tpar, 0);           //Al      
-     gMC->Gsvolu("CB4A", "BOX ", idtmed[1107], tpar, 0);     //Bakelite 
-     gMC->Gsvolu("CG4A", "BOX ", idtmed[1106], tpar, 0);     //Gas streamer
+     gMC->Gsvolu("SC4A", "BOX ", idAlu1, tpar, 0);           //Al      
+     gMC->Gsvolu("SB4A", "BOX ", idtmed[1107], tpar, 0);     //Bakelite 
+     gMC->Gsvolu("SG4A", "BOX ", idtmed[1106], tpar, 0);     //Gas streamer
 
 // chamber type A
      tpar[0] = -1.;
@@ -1538,15 +1801,15 @@ void AliMUONv1::CreateGeometry()
      const Float_t kYMC4Ap=0.;
           
      tpar[2] = 0.1;    
-     gMC->Gsposp("CG4A", 1, "CB4A", 0., 0., 0., 0, "ONLY",tpar,3);
+     gMC->Gsposp("SG4A", 1, "SB4A", 0., 0., 0., 0, "ONLY",tpar,3);
      tpar[2] = 0.3;
-     gMC->Gsposp("CB4A", 1, "CC4A", 0., 0., 0., 0, "ONLY",tpar,3);
+     gMC->Gsposp("SB4A", 1, "SC4A", 0., 0., 0., 0, "ONLY",tpar,3);
 
      tpar[2] = 0.4;
      tpar[0] = ((kXMC1MAX-kXMC1MED)/2.)*kZ14;
      tpar[1] = kYMC1MIN*kZ14;
-     gMC->Gsposp("CC4A", 1, "CM22",kXMC4A,kYMC4Am,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 2, "CM22",-kXMC4A,kYMC4Ap,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 1, "SM22",kXMC4A,kYMC4Am,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 2, "SM22",-kXMC4A,kYMC4Ap,kZMCp, 0, "ONLY", tpar, 3);
      
 
 //  chamber type B    
@@ -1556,10 +1819,10 @@ void AliMUONv1::CreateGeometry()
      const Float_t kXMC4B=kXMC1B*kZ14;
      const Float_t kYMC4Bp=kYMC1Bp*kZ14;
      const Float_t kYMC4Bm=kYMC1Bm*kZ14;
-     gMC->Gsposp("CC4A", 3, "CM22",kXMC4B,kYMC4Bp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 4, "CM22",-kXMC4B,kYMC4Bm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 5, "CM22",kXMC4B,-kYMC4Bp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 6, "CM22",-kXMC4B,-kYMC4Bm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 3, "SM22",kXMC4B,kYMC4Bp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 4, "SM22",-kXMC4B,kYMC4Bm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 5, "SM22",kXMC4B,-kYMC4Bp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 6, "SM22",-kXMC4B,-kYMC4Bm,kZMCm, 0, "ONLY", tpar, 3);
 
      
 //  chamber type C   (end of type B !!)      
@@ -1569,10 +1832,10 @@ void AliMUONv1::CreateGeometry()
      const Float_t kXMC4C=kXMC1C*kZ14;
      const Float_t kYMC4Cp=kYMC1Cp*kZ14;
      const Float_t kYMC4Cm=kYMC1Cm*kZ14;     
-     gMC->Gsposp("CC4A", 7, "CM22",kXMC4C,kYMC4Cp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 8, "CM22",-kXMC4C,kYMC4Cm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 9, "CM22",kXMC4C,-kYMC4Cp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 10, "CM22",-kXMC4C,-kYMC4Cm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 7, "SM22",kXMC4C,kYMC4Cp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 8, "SM22",-kXMC4C,kYMC4Cm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 9, "SM22",kXMC4C,-kYMC4Cp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 10, "SM22",-kXMC4C,-kYMC4Cm,kZMCm, 0, "ONLY", tpar, 3);
 
      
 //  chamber type D, E and F (same size)      
@@ -1582,29 +1845,29 @@ void AliMUONv1::CreateGeometry()
      const Float_t kXMC4D=kXMC1D*kZ14;
      const Float_t kYMC4Dp=kYMC1Dp*kZ14;
      const Float_t kYMC4Dm=kYMC1Dm*kZ14;          
-     gMC->Gsposp("CC4A", 11, "CM22",kXMC4D,kYMC4Dm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 12, "CM22",-kXMC4D,kYMC4Dp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 13, "CM22",kXMC4D,-kYMC4Dm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 14, "CM22",-kXMC4D,-kYMC4Dp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 11, "SM22",kXMC4D,kYMC4Dm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 12, "SM22",-kXMC4D,kYMC4Dp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 13, "SM22",kXMC4D,-kYMC4Dm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 14, "SM22",-kXMC4D,-kYMC4Dp,kZMCp, 0, "ONLY", tpar, 3);
 
      const Float_t kYMC4Ep=kYMC1Ep*kZ14;
      const Float_t kYMC4Em=kYMC1Em*kZ14;          
-     gMC->Gsposp("CC4A", 15, "CM22",kXMC4D,kYMC4Ep,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 16, "CM22",-kXMC4D,kYMC4Em,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 17, "CM22",kXMC4D,-kYMC4Ep,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 18, "CM22",-kXMC4D,-kYMC4Em,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 15, "SM22",kXMC4D,kYMC4Ep,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 16, "SM22",-kXMC4D,kYMC4Em,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 17, "SM22",kXMC4D,-kYMC4Ep,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 18, "SM22",-kXMC4D,-kYMC4Em,kZMCm, 0, "ONLY", tpar, 3);
 
      const Float_t kYMC4Fp=kYMC1Fp*kZ14;
      const Float_t kYMC4Fm=kYMC1Fm*kZ14;          
-     gMC->Gsposp("CC4A", 19, "CM22",kXMC4D,kYMC4Fm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 20, "CM22",-kXMC4D,kYMC4Fp,kZMCp, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 21, "CM22",kXMC4D,-kYMC4Fm,kZMCm, 0, "ONLY", tpar, 3);
-     gMC->Gsposp("CC4A", 22, "CM22",-kXMC4D,-kYMC4Fp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 19, "SM22",kXMC4D,kYMC4Fm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 20, "SM22",-kXMC4D,kYMC4Fp,kZMCp, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 21, "SM22",kXMC4D,-kYMC4Fm,kZMCm, 0, "ONLY", tpar, 3);
+     gMC->Gsposp("SC4A", 22, "SM22",-kXMC4D,-kYMC4Fp,kZMCp, 0, "ONLY", tpar, 3);
      
 
 // Positioning second plane of station 2 in ALICE
      
-     gMC->Gspos("CM22", 1, "ALIC", 0., 0., zpos4, 0, "ONLY");
+     gMC->Gspos("SM22", 1, "ALIC", 0., 0., zpos4, 0, "ONLY");
 
 // End of geometry definition for the second plane of station 2
 
@@ -1619,7 +1882,7 @@ void AliMUONv1::CreateMaterials()
 {
   // *** DEFINITION OF AVAILABLE MUON MATERIALS *** 
   //
-  //     Ar-CO2 gas 
+  //     Ar-CO2 gas (80%+20%)
     Float_t ag1[3]   = { 39.95,12.01,16. };
     Float_t zg1[3]   = { 18.,6.,8. };
     Float_t wg1[3]   = { .8,.0667,.13333 };
@@ -1742,7 +2005,7 @@ void AliMUONv1::Init()
    // Initialize Tracking Chambers
    //
 
-   printf("\n\n\n Start Init for version 1 - CPC chamber type\n\n\n");
+   if(fDebug) printf("\n%s: Start Init for version 1 - CPC chamber type\n\n",ClassName());
    Int_t i;
    for (i=0; i<AliMUONConstants::NCh(); i++) {
        ( (AliMUONChamber*) (*fChambers)[i])->Init();
@@ -1751,29 +2014,34 @@ void AliMUONv1::Init()
    //
    // Set the chamber (sensitive region) GEANT identifier
    AliMC* gMC = AliMC::GetMC(); 
-   ((AliMUONChamber*)(*fChambers)[0])->SetGid(gMC->VolId("C01G"));
-   ((AliMUONChamber*)(*fChambers)[1])->SetGid(gMC->VolId("C02G"));
-   ((AliMUONChamber*)(*fChambers)[2])->SetGid(gMC->VolId("C03G"));
-   ((AliMUONChamber*)(*fChambers)[3])->SetGid(gMC->VolId("C04G"));
+   ((AliMUONChamber*)(*fChambers)[0])->SetGid(gMC->VolId("S01G"));
+   ((AliMUONChamber*)(*fChambers)[1])->SetGid(gMC->VolId("S02G"));
+
+   ((AliMUONChamber*)(*fChambers)[2])->SetGid(gMC->VolId("S03G"));
+   ((AliMUONChamber*)(*fChambers)[3])->SetGid(gMC->VolId("S04G"));
+
    ((AliMUONChamber*)(*fChambers)[4])->SetGid(gMC->VolId("S05G"));
    ((AliMUONChamber*)(*fChambers)[5])->SetGid(gMC->VolId("S06G"));
+
    ((AliMUONChamber*)(*fChambers)[6])->SetGid(gMC->VolId("S07G"));
    ((AliMUONChamber*)(*fChambers)[7])->SetGid(gMC->VolId("S08G"));
+
    ((AliMUONChamber*)(*fChambers)[8])->SetGid(gMC->VolId("S09G"));
    ((AliMUONChamber*)(*fChambers)[9])->SetGid(gMC->VolId("S10G"));
-   ((AliMUONChamber*)(*fChambers)[10])->SetGid(gMC->VolId("CG1A"));
-   ((AliMUONChamber*)(*fChambers)[11])->SetGid(gMC->VolId("CG2A"));
-   ((AliMUONChamber*)(*fChambers)[12])->SetGid(gMC->VolId("CG3A"));
-   ((AliMUONChamber*)(*fChambers)[13])->SetGid(gMC->VolId("CG4A"));
 
-   printf("\n\n\n Finished Init for version 0 - CPC chamber type\n\n\n");
+   ((AliMUONChamber*)(*fChambers)[10])->SetGid(gMC->VolId("SG1A"));
+   ((AliMUONChamber*)(*fChambers)[11])->SetGid(gMC->VolId("SG2A"));
+   ((AliMUONChamber*)(*fChambers)[12])->SetGid(gMC->VolId("SG3A"));
+   ((AliMUONChamber*)(*fChambers)[13])->SetGid(gMC->VolId("SG4A"));
+
+   if(fDebug) printf("\n%s: Finished Init for version 1 - CPC chamber type\n",ClassName());
 
    //cp 
-   printf("\n\n\n Start Init for Trigger Circuits\n\n\n");
+   if(fDebug) printf("\n%s: Start Init for Trigger Circuits\n",ClassName());
    for (i=0; i<AliMUONConstants::NTriggerCircuit(); i++) {
      ( (AliMUONTriggerCircuit*) (*fTriggerCircuits)[i])->Init(i);
    }
-   printf(" Finished Init for Trigger Circuits\n\n\n");
+   if(fDebug) printf("%s: Finished Init for Trigger Circuits\n",ClassName());
    //cp
 
 }
@@ -1789,17 +2057,14 @@ void AliMUONv1::StepManager()
   TLorentzVector mom;
   Float_t        theta,phi;
   Float_t        destep, step;
-  
+
   static Float_t eloss, eloss2, xhit, yhit, zhit, tof, tlength;
-  const  Float_t kBig=1.e10;
-  //  modifs perso
+  const  Float_t kBig = 1.e10;
   static Float_t hits[15];
 
   TClonesArray &lhits = *fHits;
 
   //
-  // Set maximum step size for gas
-  // numed=gMC->GetMedium();
   //
   // Only charged tracks
   if( !(gMC->TrackCharge()) ) return; 
@@ -1809,10 +2074,10 @@ void AliMUONv1::StepManager()
   idvol=-1;
   id=gMC->CurrentVolID(copy);
   
-    for (Int_t i=1; i<=AliMUONConstants::NCh(); i++) {
+    for (Int_t i = 1; i <= AliMUONConstants::NCh(); i++) {
       if(id==((AliMUONChamber*)(*fChambers)[i-1])->GetGid()){ 
-         vol[0]=i; 
-         idvol=i-1;
+         vol[0] = i; 
+         idvol  = i-1;
       }
     }
     if (idvol == -1) return;
@@ -1822,8 +2087,6 @@ void AliMUONv1::StepManager()
   gMC->TrackMomentum(mom);
 
   ipart  = gMC->TrackPid();
-  //Int_t ipart1 = gMC->IdFromPDG(ipart);
-  //printf("ich, ipart %d %d \n",vol[0],ipart1);
 
   //
   // momentum loss and steplength in last step
@@ -1837,44 +2100,41 @@ void AliMUONv1::StepManager()
       Double_t tc = mom[0]*mom[0]+mom[1]*mom[1];
       Double_t rt = TMath::Sqrt(tc);
       Double_t pmom = TMath::Sqrt(tc+mom[2]*mom[2]);
-      Double_t tx=mom[0]/pmom;
-      Double_t ty=mom[1]/pmom;
-      Double_t tz=mom[2]/pmom;
-      Double_t s=((AliMUONChamber*)(*fChambers)[idvol])
+      Double_t tx = mom[0]/pmom;
+      Double_t ty = mom[1]/pmom;
+      Double_t tz = mom[2]/pmom;
+      Double_t s  = ((AliMUONChamber*)(*fChambers)[idvol])
          ->ResponseModel()
          ->Pitch()/tz;
       theta   = Float_t(TMath::ATan2(rt,Double_t(mom[2])))*kRaddeg;
       phi     = Float_t(TMath::ATan2(Double_t(mom[1]),Double_t(mom[0])))*kRaddeg;
       hits[0] = Float_t(ipart);         // Geant3 particle type
-      hits[1] = pos[0]+s*tx;                 // X-position for hit
-      hits[2] = pos[1]+s*ty;                 // Y-position for hit
-      hits[3] = pos[2]+s*tz;                 // Z-position for hit
+      hits[1] = pos[0]+s*tx;            // X-position for hit
+      hits[2] = pos[1]+s*ty;            // Y-position for hit
+      hits[3] = pos[2]+s*tz;            // Z-position for hit
       hits[4] = theta;                  // theta angle of incidence
       hits[5] = phi;                    // phi angle of incidence 
-      hits[8] = (Float_t) fNPadHits;   // first padhit
+      hits[8] = (Float_t) fNPadHits;    // first padhit
       hits[9] = -1;                     // last pad hit
-
-      // modifs perso
-      hits[10] = mom[3]; // hit momentum P
-      hits[11] = mom[0]; // Px/P
-      hits[12] = mom[1]; // Py/P
-      hits[13] = mom[2]; // Pz/P
-      // fin modifs perso
+      hits[10] = mom[3];                // hit momentum P
+      hits[11] = mom[0];                // Px
+      hits[12] = mom[1];                // Py
+      hits[13] = mom[2];                // Pz
       tof=gMC->TrackTime();
-      hits[14] = tof;    // Time of flight
-      // phi angle of incidence
-      tlength = 0;
-      eloss   = 0;
-      eloss2  = 0;
-      xhit    = pos[0];
-      yhit    = pos[1];      
-      zhit    = pos[2];      
+      hits[14] = tof;                   // Time of flight
+      tlength  = 0;
+      eloss    = 0;
+      eloss2   = 0;
+      xhit     = pos[0];
+      yhit     = pos[1];      
+      zhit     = pos[2];      
+      Chamber(idvol).ChargeCorrelationInit();
       // Only if not trigger chamber
 
       
       
 
-      if(idvol<AliMUONConstants::NTrackingCh()) {
+      if(idvol < AliMUONConstants::NTrackingCh()) {
          //
          //  Initialize hit position (cursor) in the segmentation model 
          ((AliMUONChamber*) (*fChambers)[idvol])
@@ -1900,33 +2160,34 @@ void AliMUONv1::StepManager()
       Float_t globalPos[3] = {pos[0], pos[1], pos[2]};
       gMC->Gmtod(globalPos,localPos,1); 
 
-      if(idvol<AliMUONConstants::NTrackingCh()) {
+      if(idvol < AliMUONConstants::NTrackingCh()) {
 // tracking chambers
          x0 = 0.5*(xhit+pos[0]);
          y0 = 0.5*(yhit+pos[1]);
          z0 = 0.5*(zhit+pos[2]);
-         //      z0 = localPos[2];
       } else {
 // trigger chambers
-         x0=xhit;
-         y0=yhit;
-//       z0=yhit;
-         z0=0.;
+         x0 = xhit;
+         y0 = yhit;
+         z0 = 0.;
       }
       
 
       if (eloss >0)  MakePadHits(x0,y0,z0,eloss,tof,idvol);
       
          
-      hits[6]=tlength;
-      hits[7]=eloss2;
+      hits[6] = tlength;   // track length
+      hits[7] = eloss2;    // de/dx energy loss
+
       if (fNPadHits > (Int_t)hits[8]) {
-         hits[8]= hits[8]+1;
-         hits[9]= (Float_t) fNPadHits;
+         hits[8] = hits[8]+1;
+         hits[9] = (Float_t) fNPadHits;
       }
-    
+//
+//    new hit 
+      
       new(lhits[fNhits++]) 
-         AliMUONHit(fIshunt,gAlice->CurrentTrack(),vol,hits);
+         AliMUONHit(fIshunt, gAlice->CurrentTrack(), vol,hits);
       eloss = 0; 
       //
       // Check additional signal generation conditions 
@@ -1944,13 +2205,14 @@ void AliMUONv1::StepManager()
       Float_t globalPos[3] = {pos[0], pos[1], pos[2]};
       gMC->Gmtod(globalPos,localPos,1); 
 
+      eloss    += destep;
 
       if (eloss > 0 && idvol < AliMUONConstants::NTrackingCh())
        MakePadHits(0.5*(xhit+pos[0]),0.5*(yhit+pos[1]),pos[2],eloss,tof,idvol);
       xhit     = pos[0];
       yhit     = pos[1]; 
-      zhit     = pos[2]; 
-      eloss    = destep;
+      zhit     = pos[2];
+      eloss = 0;
       tlength += step ;
       //
       // nothing special  happened, add up energy loss