TPC/AliTPCv2.cxx

   1 /**************************************************************************
   2  * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
   3  *                                                                        *
   4  * Author: The ALICE Off-line Project.                                    *
   5  * Contributors are mentioned in the code where appropriate.              *
   6  *                                                                        *
   7  * Permission to use, copy, modify and distribute this software and its   *
   8  * documentation strictly for non-commercial purposes is hereby granted   *
   9  * without fee, provided that the above copyright notice appears in all   *
  10  * copies and that both the copyright notice and this permission notice   *
  11  * appear in the supporting documentation. The authors make no claims     *
  12  * about the suitability of this software for any purpose. It is          *
  13  * provided "as is" without express or implied warranty.                  *
  14  **************************************************************************/
  15
  16 /* $Id$ */
  17
  18 //
  19 ///////////////////////////////////////////////////////////////////////////////
  20 //                                                                           //
  21 //  Time Projection Chamber version 2 -- detailed TPC and slow simulation    //
  22 //                                                                           //
  23 //Begin_Html
  24 /*
  25 <img src="picts/AliTPCv2Class.gif">
  26 */
  27 //End_Html
  28 //                                                                           //
  29 //                                                                           //
  30 ///////////////////////////////////////////////////////////////////////////////
  31
  32 //#include <stdlib.h>
  33
  34 #include <TLorentzVector.h>
  35 #include <TPDGCode.h>
  36 #include <TString.h>
  37 #include "AliLog.h"
  38 #include "AliMathBase.h"
  39 #include "AliTrackReference.h"
  40 #include "AliTPCParam.h"
  41 #include "AliTPCTrackHitsV2.h"
  42 #include "AliTPCv2.h"
  43 #include "AliGeomManager.h"
  44 #include "TGeoVolume.h"
  45 #include "TGeoPcon.h"
  46 #include "TGeoTube.h"
  47 #include "TGeoPgon.h"
  48 #include "TGeoTrd1.h"
  49 #include "TGeoCompositeShape.h"
  50 #include "TGeoPara.h"
  51 #include "TGeoPhysicalNode.h"
  52
  53 ClassImp(AliTPCv2)
  54
  55 //_____________________________________________________________________________
  56 AliTPCv2::AliTPCv2(const char *name, const char *title) :
  57   AliTPC(name, title),
  58   fIdSens(0),
  59   fIDrift(0),
  60   fSecOld(0)
  61 {
  62   //
  63   // Standard constructor for Time Projection Chamber version 2
  64   //
  65
  66
  67   SetBufferSize(128000);
  68
  69
  70 //   if (fTPCParam)
  71 //      fTPCParam->Write(fTPCParam->GetTitle());
  72 }
  73
  74 //_____________________________________________________________________________
  75 void AliTPCv2::CreateGeometry()
  76 {
  77   //
  78   // Create the geometry of Time Projection Chamber version 2
  79   //
  80   //Begin_Html
  81   /*
  82     <img src="picts/AliTPC.gif">
  83   */
  84   //End_Html
  85   //Begin_Html
  86   /*
  87     <img src="picts/AliTPCv2Tree.gif">
  88   */
  89   //End_Html
  90
  91   //----------------------------------------------------------
  92   // This geometry is written using TGeo class
  93   // Firstly the shapes are defined, and only then the volumes
  94   // What is recognized by the MC are volumes
  95   //----------------------------------------------------------
  96   //
  97   //  tpc - this will be the mother volume
  98   //
  99
 100   //
 101   // here I define a volume TPC
 102   // retrive the medium name with "TPC_" as a leading string
 103   //
 104   TGeoPcon *tpc = new TGeoPcon(0.,360.,20); //20 sections
 105   //
 106   tpc->DefineSection(0,-291.,77.,278.);
 107   tpc->DefineSection(1,-270,77.,278.);
 108   //
 109   tpc->DefineSection(2,-270.,77.,278.);
 110   tpc->DefineSection(3,-259.6,70.,278.);
 111   //
 112   tpc->DefineSection(4,-259.6,68.1,278.);
 113   tpc->DefineSection(5,-253.6,68.1,278.);
 114   //
 115   tpc->DefineSection(6,-253.6,68.,278.);
 116   tpc->DefineSection(7,-74.0,60.8,278.);
 117   //
 118   tpc->DefineSection(8,-74.0,60.1,278.);
 119   tpc->DefineSection(9,-73.3,60.1,278.);
 120   //
 121   tpc->DefineSection(10,-73.3,56.9,278.);
 122   tpc->DefineSection(11,73.3,56.9,278.);
 123   //
 124   tpc->DefineSection(12,73.3,60.1,278.);
 125   tpc->DefineSection(13,74.0,60.1,278.);
 126   //
 127   tpc->DefineSection(14,74.0,60.8,278.);
 128   tpc->DefineSection(15,253.6,65.5,278.);
 129   //
 130   tpc->DefineSection(16,253.6,65.6,278.);
 131   tpc->DefineSection(17,259.6,65.6,278.);
 132   //
 133   tpc->DefineSection(18,259.6,70.0,278.);
 134   tpc->DefineSection(19,291.,77.,278.);
 135   //
 136   TGeoMedium *m1 = gGeoManager->GetMedium("TPC_Air");
 137   TGeoVolume *v1 = new TGeoVolume("TPC_M",tpc,m1);
 138   //
 139   // drift volume - sensitive volume, extended beyond the
 140   // endcaps, because of the alignment
 141   //
 142   TGeoPcon *dvol = new TGeoPcon(0.,360.,6);
 143   dvol->DefineSection(0,-260.,74.5,264.4);
 144   dvol->DefineSection(1,-253.6,74.5,264.4);
 145   //
 146   dvol->DefineSection(2,-253.6,76.6774,258.);
 147   dvol->DefineSection(3,253.6,76.6774,258.);
 148   //
 149   dvol->DefineSection(4,253.6,74.5,264.4);
 150   dvol->DefineSection(5,260.,74.5,264.4);
 151   //
 152   TGeoMedium *m5 = gGeoManager->GetMedium("TPC_Ne-CO2-N-2");
 153   TGeoVolume *v9 = new TGeoVolume("TPC_Drift",dvol,m5);
 154   //
 155   v1->AddNode(v9,1);
 156   //
 157   // outer insulator
 158   //
 159   TGeoPcon *tpco = new TGeoPcon(0.,360.,6); //insulator
 160   //
 161   tpco->DefineSection(0,-256.6,264.8,278.);
 162   tpco->DefineSection(1,-253.6,264.8,278.);
 163   //
 164   tpco->DefineSection(2,-253.6,258.,278.);
 165   tpco->DefineSection(3,250.6,258.,278.);
 166   //
 167   tpco->DefineSection(4,250.6,258.,275.5);
 168   tpco->DefineSection(5,253.6,258.,275.5);
 169   //
 170   TGeoMedium *m2 = gGeoManager->GetMedium("TPC_CO2");
 171   TGeoVolume *v2 = new TGeoVolume("TPC_OI",tpco,m2);
 172   //
 173   // outer containment vessel
 174   //
 175   TGeoPcon *tocv = new TGeoPcon(0.,360.,6);  // containment vessel
 176   //
 177   tocv->DefineSection(0,-256.6,264.8,278.);
 178   tocv->DefineSection(1,-253.6,264.8,278.);
 179   //
 180   tocv->DefineSection(2,-253.6,274.8124,278.);
 181   tocv->DefineSection(3,247.6,274.8124,278.);
 182   //
 183   tocv->DefineSection(4,247.6,270.4,278.);
 184   tocv->DefineSection(5,250.6,270.4,278.);
 185   //
 186   TGeoMedium *m3 = gGeoManager->GetMedium("TPC_Al");
 187   TGeoVolume *v3 = new TGeoVolume("TPC_OCV",tocv,m3);
 188   //
 189   TGeoTube *to1 = new TGeoTube(274.8174,277.995,252.1); //epoxy
 190   TGeoTube *to2 = new TGeoTube(274.8274,277.985,252.1); //tedlar
 191   TGeoTube *to3 = new TGeoTube(274.8312,277.9812,252.1);//prepreg2
 192   TGeoTube *to4 = new TGeoTube(274.9062,277.9062,252.1);//nomex
 193   //
 194   TGeoMedium *sm1 = gGeoManager->GetMedium("TPC_Epoxy");
 195   TGeoMedium *sm2 = gGeoManager->GetMedium("TPC_Tedlar");
 196   TGeoMedium *sm3 = gGeoManager->GetMedium("TPC_Prepreg2");
 197   TGeoMedium *sm4 = gGeoManager->GetMedium("TPC_Nomex");
 198   //
 199   TGeoVolume *tov1 = new TGeoVolume("TPC_OCV1",to1,sm1);
 200   TGeoVolume *tov2 = new TGeoVolume("TPC_OCV2",to2,sm2);
 201   TGeoVolume *tov3 = new TGeoVolume("TPC_OCV3",to3,sm3);
 202   TGeoVolume *tov4 = new TGeoVolume("TPC_OCV4",to4,sm4);
 203  //-------------------------------------------------------
 204   //  Tpc Outer Field Cage
 205   //  daughters - composite (sandwich)
 206   //-------------------------------------------------------
 207
 208   TGeoPcon *tofc = new TGeoPcon(0.,360.,6);
 209   //
 210   tofc->DefineSection(0,-253.6,258.,269.6);
 211   tofc->DefineSection(1,-250.6,258.,269.6);
 212   //
 213   tofc->DefineSection(2,-250.6,258.,260.0676);
 214   tofc->DefineSection(3,250.6,258.,260.0676);
 215   //
 216   tofc->DefineSection(4,250.6,258.,275.5);
 217   tofc->DefineSection(5,253.6,258.,275.5);
 218   //
 219   TGeoVolume *v4 = new TGeoVolume("TPC_TOFC",tofc,m3);
 220   //sandwich
 221   TGeoTube *tf1 = new TGeoTube(258.0,260.0676,252.1); //tedlar
 222   TGeoTube *tf2 = new TGeoTube(258.0038,260.0638,252.1); //prepreg3
 223   TGeoTube *tf3 = new TGeoTube(258.0338,260.0338,252.1);//nomex
 224   //
 225   TGeoMedium *sm5 = gGeoManager->GetMedium("TPC_Prepreg3");
 226   //
 227   TGeoVolume *tf1v = new TGeoVolume("TPC_OFC1",tf1,sm2);
 228   TGeoVolume *tf2v = new TGeoVolume("TPC_OFC2",tf2,sm5);
 229   TGeoVolume *tf3v = new TGeoVolume("TPC_OFC3",tf3,sm4);
 230   //
 231   // outer part - positioning
 232   //
 233   tov1->AddNode(tov2,1); tov2->AddNode(tov3,1); tov3->AddNode(tov4,1);
 234   //
 235   tf1v->AddNode(tf2v,1); tf2v->AddNode(tf3v,1);
 236   //
 237   v3->AddNode(tov1,1,new TGeoTranslation(0.,0.,-1.5)); v4->AddNode(tf1v,1);
 238   //
 239   v2->AddNode(v3,1); v2->AddNode(v4,1);
 240   //
 241   v1->AddNode(v2,1);
 242   //--------------------------------------------------------------------
 243   // Tpc Inner INsulator (CO2)
 244   // the cones, the central drum and the inner f.c. sandwich with a piece
 245   // of the flane will be placed in the TPC
 246   //--------------------------------------------------------------------
 247   TGeoPcon *tpci = new TGeoPcon(0.,360.,4);
 248   //
 249   tpci->DefineSection(0,-253.6,68.4,76.6774);
 250   tpci->DefineSection(1,-74.0,61.2,76.6774);
 251   //
 252   tpci->DefineSection(2,74.0,61.2,76.6774);
 253   //
 254   tpci->DefineSection(3,253.6,65.9,76.6774);
 255   //
 256   TGeoVolume *v5 = new TGeoVolume("TPC_INI",tpci,m2);
 257   //
 258   // now the inner field cage - only part of flanges (2 copies)
 259   //
 260   TGeoTube *tif1 = new TGeoTube(69.9,76.6774,1.5);
 261   TGeoVolume *v6 = new TGeoVolume("TPC_IFC1",tif1,m3);
 262   //
 263  //---------------------------------------------------------
 264   // Tpc Inner Containment vessel - Muon side
 265   //---------------------------------------------------------
 266   TGeoPcon *tcms = new TGeoPcon(0.,360.,10);
 267   //
 268   tcms->DefineSection(0,-259.1,68.1,74.2);
 269   tcms->DefineSection(1,-253.6,68.1,74.2);
 270   //
 271   tcms->DefineSection(2,-253.6,68.1,68.4);
 272   tcms->DefineSection(3,-74.0,60.9,61.2);
 273   //
 274   tcms->DefineSection(4,-74.0,60.1,61.2);
 275   tcms->DefineSection(5,-73.3,60.1,61.2);
 276   //
 277   tcms->DefineSection(6,-73.3,56.9,61.2);
 278   tcms->DefineSection(7,-73.0,56.9,61.2);
 279   //
 280   tcms->DefineSection(8,-73.0,56.9,58.8);
 281   tcms->DefineSection(9,-71.3,56.9,58.8);
 282   //
 283   TGeoVolume *v7 = new TGeoVolume("TPC_ICVM",tcms,m3);
 284   //-----------------------------------------------
 285   // inner containment vessel - shaft side
 286   //-----------------------------------------------
 287   TGeoPcon *tcss = new TGeoPcon(0.,360.,10);
 288   //
 289   tcss->DefineSection(0,71.3,56.9,58.8);
 290   tcss->DefineSection(1,73.0,56.9,58.8);
 291   //
 292   tcss->DefineSection(2,73.0,56.9,61.2);
 293   tcss->DefineSection(3,73.3,56.9,61.2);
 294   //
 295   tcss->DefineSection(4,73.3,60.1,61.2);
 296   tcss->DefineSection(5,74.0,60.1,61.2);
 297   //
 298   tcss->DefineSection(6,74.0,60.9,61.2);
 299   tcss->DefineSection(7,253.6,65.6,65.9);
 300   //
 301   tcss->DefineSection(8,253.6,65.6,74.2);
 302   tcss->DefineSection(9,258.1,65.6,74.2);
 303   //
 304   TGeoVolume *v8 = new TGeoVolume("TPC_ICVS",tcss,m3);
 305   //-----------------------------------------------
 306   //  Inner field cage
 307   //  define 4 parts and make an assembly
 308   //-----------------------------------------------
 309   // part1 - Al - 2 copies
 310   TGeoTube *t1 = new TGeoTube(76.6774,78.845,0.75);
 311   TGeoVolume *tv1 = new TGeoVolume("TPC_IFC2",t1,m3);
 312   // sandwich - outermost parts - 2 copies
 313   TGeoTube *t2 = new TGeoTube(76.6774,78.845,74.175); // tedlar 38 microns
 314   TGeoTube *t3 = new TGeoTube(76.6812,78.8412,74.175); // prepreg2 500 microns
 315   TGeoTube *t4 = new TGeoTube(76.7312,78.7912,74.175); // prepreg3 300 microns
 316   TGeoTube *t5 = new TGeoTube(76.7612,78.7612,74.175); // nomex 2 cm
 317   //
 318   TGeoVolume *tv2 = new TGeoVolume("TPC_IFC3",t2,sm2);
 319   TGeoVolume *tv3 = new TGeoVolume("TPC_IFC4",t3,sm3);
 320   TGeoVolume *tv4 = new TGeoVolume("TPC_IFC5",t4,sm5);
 321   TGeoVolume *tv5 = new TGeoVolume("TPC_IFC6",t5,sm4);
 322   //
 323   // middle parts - 2 copies
 324   TGeoTube *t6 = new TGeoTube(76.6774,78.795,5.); // tedlar 38 microns
 325   TGeoTube *t7 = new TGeoTube(76.6812,78.7912,5.); // prepreg2 250 microns
 326   TGeoTube *t8 = new TGeoTube(76.7062,78.7662,5.); // prepreg3 300 microns
 327   TGeoTube *t9 = new TGeoTube(76.7362,78.7362,5.); // nomex 2 cm
 328   //
 329   TGeoVolume *tv6 = new TGeoVolume("TPC_IFC7",t6,sm2);
 330   TGeoVolume *tv7 = new TGeoVolume("TPC_IFC8",t7,sm3);
 331   TGeoVolume *tv8 = new TGeoVolume("TPC_IFC9",t8,sm5);
 332   TGeoVolume *tv9 = new TGeoVolume("TPC_IFC10",t9,sm4);
 333   // central part - 1 copy
 334   TGeoTube *t10 = new TGeoTube(76.6774,78.745,93.75); // tedlar 38 microns
 335   TGeoTube *t11 = new TGeoTube(76.6812,78.7412,93.75); // prepreg3 300 microns
 336   TGeoTube *t12 = new TGeoTube(76.7112,78.7112,93.75); // nomex 2 cm
 337   //
 338   TGeoVolume *tv10 = new TGeoVolume("TPC_IFC11",t10,sm2);
 339   TGeoVolume *tv11 = new TGeoVolume("TPC_IFC12",t11,sm5);
 340   TGeoVolume *tv12 = new TGeoVolume("TPC_IFC13",t12,sm4);
 341   //
 342   // inner part - positioning
 343   //
 344   // creating a sandwich
 345   tv2->AddNode(tv3,1); tv3->AddNode(tv4,1); tv4->AddNode(tv5,1);
 346   //
 347   tv6->AddNode(tv7,1); tv7->AddNode(tv8,1); tv8->AddNode(tv9,1);
 348   //
 349   tv10->AddNode(tv11,1); tv11->AddNode(tv12,1);
 350   //
 351   TGeoVolumeAssembly *tv100 = new TGeoVolumeAssembly("TPC_IFC");
 352   //
 353   tv100->AddNode(tv10,1);
 354   tv100->AddNode(tv6,1,new TGeoTranslation(0.,0.,-98.75));
 355   tv100->AddNode(tv6,2,new TGeoTranslation(0.,0.,98.75));
 356   tv100->AddNode(tv2,1,new TGeoTranslation(0.,0.,-177.925));
 357   tv100->AddNode(tv2,2,new TGeoTranslation(0.,0.,177.925));
 358   tv100->AddNode(tv1,1,new TGeoTranslation(0.,0.,-252.85));
 359   tv100->AddNode(tv1,2,new TGeoTranslation(0.,0.,252.85));
 360   //
 361   v5->AddNode(v6,1, new TGeoTranslation(0.,0.,-252.1));
 362   v5->AddNode(v6,2, new TGeoTranslation(0.,0.,252.1));
 363   v1->AddNode(v5,1); v1->AddNode(v7,1); v1->AddNode(v8,1);
 364   v9->AddNode(tv100,1);
 365   //
 366   // central drum
 367   //
 368   // flange + sandwich
 369   //
 370   TGeoPcon *cfl = new TGeoPcon(0.,360.,6);
 371   cfl->DefineSection(0,-71.1,59.7,61.2);
 372   cfl->DefineSection(1,-68.6,59.7,61.2);
 373   //
 374   cfl->DefineSection(2,-68.6,60.6324,61.2);
 375   cfl->DefineSection(3,68.6,60.6324,61.2);
 376   //
 377   cfl->DefineSection(4,68.6,59.7,61.2);
 378   cfl->DefineSection(5,71.1,59.7,61.2);
 379   //
 380   TGeoVolume *cflv = new TGeoVolume("TPC_CDR",cfl,m3);
 381   // sandwich
 382   TGeoTube *cd1 = new TGeoTube(60.6424,61.19,71.1);
 383   TGeoTube *cd2 = new TGeoTube(60.6462,61.1862,71.1);
 384   TGeoTube *cd3 = new TGeoTube(60.6662,61.1662,71.1);
 385   //
 386   TGeoMedium *sm6 = gGeoManager->GetMedium("TPC_Prepreg1");
 387   TGeoVolume *cd1v = new TGeoVolume("TPC_CDR1",cd1,sm2); //tedlar
 388   TGeoVolume *cd2v = new TGeoVolume("TPC_CDR2",cd2,sm6);// prepreg1
 389   TGeoVolume *cd3v = new TGeoVolume("TPC_CDR3",cd3,sm4); //nomex
 390   //
 391   // seals for central drum 2 copies
 392   //
 393   TGeoTube *cs = new TGeoTube(56.9,61.2,0.1);
 394   TGeoMedium *sm7 = gGeoManager->GetMedium("TPC_Mylar");
 395   TGeoVolume *csv = new TGeoVolume("TPC_CDRS",cs,sm7);
 396   v1->AddNode(csv,1,new TGeoTranslation(0.,0.,-71.2));
 397   v1->AddNode(csv,2,new TGeoTranslation(0.,0.,71.2));
 398   //
 399   // seal collars
 400   TGeoPcon *se = new TGeoPcon(0.,360.,6);
 401   se->DefineSection(0,-72.8,59.7,61.2);
 402   se->DefineSection(1,-72.3,59.7,61.2);
 403   //
 404   se->DefineSection(2,-72.3,58.85,61.2);
 405   se->DefineSection(3,-71.6,58.85,61.2);
 406   //
 407   se->DefineSection(4,-71.6,59.7,61.2);
 408   se->DefineSection(5,-71.3,59.7,61.2);
 409   //
 410   TGeoVolume *sev = new TGeoVolume("TPC_CDCE",se,m3);
 411   //
 412   TGeoTube *si = new TGeoTube(56.9,58.8,1.);
 413   TGeoVolume *siv = new TGeoVolume("TPC_CDCI",si,m3);
 414   //
 415   // define reflection matrix
 416   //
 417   TGeoRotation *ref = new TGeoRotation("ref",90.,0.,90.,90.,180.,0.);
 418   //
 419   cd1v->AddNode(cd2v,1); cd2v->AddNode(cd3v,1); cflv->AddNode(cd1v,1);
 420   //
 421   v1->AddNode(siv,1,new TGeoTranslation(0.,0.,-69.9));
 422   v1->AddNode(siv,2,new TGeoTranslation(0.,0.,69.9));
 423   v1->AddNode(sev,1); v1->AddNode(sev,2,ref); v1->AddNode(cflv,1);
 424   //
 425   // central membrane - 2 rings and a mylar membrane - assembly
 426   //
 427   TGeoTube *ih = new TGeoTube(81.05,84.05,0.3);
 428   TGeoTube *oh = new TGeoTube(250.,256.,.5);
 429   TGeoTube *mem = new TGeoTube(84.05,250,0.01);
 430   TGeoVolume *ihv = new TGeoVolume("TPC_IHVH",ih,m3);
 431   TGeoVolume *ohv = new TGeoVolume("TPC_OHVH",oh,m3);
 432   TGeoVolume *memv = new TGeoVolume("TPC_HV",mem,sm7);
 433   //
 434   TGeoVolumeAssembly *cm = new TGeoVolumeAssembly("TPC_HVMEM");
 435   cm->AddNode(ihv,1);
 436   cm->AddNode(ohv,1);
 437   cm->AddNode(memv,1);
 438   v9->AddNode(cm,1);
 439   //
 440   // end caps - they are make as an assembly of single segments
 441   // containing both readout chambers
 442   //
 443   Double_t openingAngle = 10.*TMath::DegToRad();
 444   Double_t thick=1.5; // rib
 445   Double_t shift = thick/TMath::Sin(openingAngle);
 446   //
 447   Double_t lowEdge = 86.3; // hole in the wheel
 448   Double_t upEdge = 240.4; // hole in the wheel
 449   //
 450   new TGeoTubeSeg("sec",74.5,264.4,3.,0.,20.);
 451   //
 452   TGeoPgon *hole = new TGeoPgon("hole",0.,20.,1,4);
 453   //
 454   hole->DefineSection(0,-3.5,lowEdge-shift,upEdge-shift);
 455   hole->DefineSection(1,-1.5,lowEdge-shift,upEdge-shift);
 456   //
 457   hole->DefineSection(2,-1.5,lowEdge-shift,upEdge+3.-shift);
 458   hole->DefineSection(3,3.5,lowEdge-shift,upEdge+3.-shift);
 459   //
 460   Double_t ys = shift*TMath::Sin(openingAngle);
 461   Double_t xs = shift*TMath::Cos(openingAngle);
 462   TGeoTranslation *tr = new TGeoTranslation("tr",xs,ys,0.);
 463   tr->RegisterYourself();
 464   TGeoCompositeShape *chamber = new TGeoCompositeShape("sec-hole:tr");
 465   TGeoVolume *sv = new TGeoVolume("TPC_WSEG",chamber,m3);
 466   TGeoPgon *bar = new TGeoPgon("bar",0.,20.,1,2);
 467   bar->DefineSection(0,-3.,131.5-shift,136.5-shift);
 468   bar->DefineSection(1,1.5,131.5-shift,136.5-shift);
 469   TGeoVolume *barv = new TGeoVolume("TPC_WBAR",bar,m3);
 470   TGeoVolumeAssembly *ch = new TGeoVolumeAssembly("TPC_WCH");//empty segment
 471   //
 472   ch->AddNode(sv,1); ch->AddNode(barv,1,tr);
 473   //
 474   // readout chambers
 475   //
 476   // IROC first
 477   //
 478    TGeoTrd1 *ibody = new TGeoTrd1(13.8742,21.3328,4.29,21.15);
 479    TGeoVolume *ibdv = new TGeoVolume("TPC_IROCB",ibody,m3);
 480   // empty space
 481    TGeoTrd1 *emp = new TGeoTrd1(12.3742,19.8328,3.99,19.65);
 482    TGeoVolume *empv = new TGeoVolume("TPC_IROCE",emp,m1);
 483    ibdv->AddNode(empv,1,new TGeoTranslation(0.,-0.3,0.));
 484    //bars
 485    Double_t tga = (19.8328-12.3742)/39.3;
 486    Double_t xmin,xmax;
 487    xmin = 9.55*tga+12.3742;
 488    xmax = 9.95*tga+12.3742;
 489    TGeoTrd1 *ib1 = new TGeoTrd1(xmin,xmax,3.29,0.2);
 490    TGeoVolume *ib1v = new TGeoVolume("TPC_IRB1",ib1,m3);
 491    empv->AddNode(ib1v,1,new TGeoTranslation("tt1",0.,0.7,-9.9));
 492    xmin=19.4*tga+12.3742;
 493    xmax=19.9*tga+12.3742;
 494    TGeoTrd1 *ib2 = new TGeoTrd1(xmin,xmax,3.29,0.25);
 495    TGeoVolume *ib2v = new TGeoVolume("TPC_TRB2",ib2,m3);
 496    empv->AddNode(ib2v,1,new TGeoTranslation(0.,0.7,0.));
 497    xmin=29.35*tga+12.3742;
 498    xmax=29.75*tga+12.3742;
 499    TGeoTrd1 *ib3 = new TGeoTrd1(xmin,xmax,3.29,0.2);
 500    TGeoVolume *ib3v = new TGeoVolume("TPC_IRB3",ib3,m3);
 501    empv->AddNode(ib3v,1,new TGeoTranslation(0.,0.7,9.9));
 502    //
 503    // holes for connectors
 504    //
 505    TGeoBBox *conn = new TGeoBBox(0.4,0.3,4.675); // identical for iroc and oroc
 506    TGeoVolume *connv = new TGeoVolume("TPC_RCCON",conn,m1);
 507    TString fileName(gSystem->Getenv("ALICE_ROOT"));
 508    fileName += "/TPC/conn_iroc.dat";
 509    ifstream in;
 510    in.open(fileName.Data(), ios_base::in); // asci file
 511    for(Int_t i =0;i<86;i++){
 512       Double_t y = 3.99;
 513       Double_t x,z,ang;
 514       in>>x>>z>>ang;
 515       z-=26.5;
 516       TGeoRotation *rrr = new TGeoRotation();
 517       rrr->RotateY(ang);
 518       TGeoCombiTrans *trans = new TGeoCombiTrans("trans",x,y,z,rrr);
 519       ibdv->AddNode(connv,i+1,trans);
 520    }
 521    in.close();
 522    // "cap"
 523    new TGeoTrd1("icap",14.5974,23.3521,1.19,24.825);
 524    // "hole"
 525    new TGeoTrd1("ihole",13.8742,21.3328,1.2,21.15);
 526    TGeoTranslation *tr1 = new TGeoTranslation("tr1",0.,0.,1.725);
 527    tr1->RegisterYourself();
 528    TGeoCompositeShape *ic = new TGeoCompositeShape("icap-ihole:tr1");
 529    TGeoVolume *icv = new TGeoVolume("TPC_IRCAP",ic,m3);
 530    //
 531    // pad plane and wire fixations
 532    //
 533    TGeoTrd1 *pp = new TGeoTrd1(14.5974,23.3521,0.3,24.825); //pad+iso
 534    TGeoMedium *m4 = gGeoManager->GetMedium("TPC_G10");
 535    TGeoVolume *ppv = new TGeoVolume("TPC_IRPP",pp,m4);
 536    TGeoPara *f1 = new TGeoPara(.6,.5,24.825,0.,-10.,0.);
 537    TGeoVolume *f1v = new TGeoVolume("TPC_IRF1",f1,m4);
 538    TGeoPara *f2 = new TGeoPara(.6,.5,24.825,0.,10.,0.);
 539    TGeoVolume *f2v = new TGeoVolume("TPC_IRF2",f2,m4);
 540    //
 541    TGeoVolumeAssembly *iroc = new TGeoVolumeAssembly("TPC_IROC");
 542    //
 543    iroc->AddNode(ibdv,1);
 544    iroc->AddNode(icv,1,new TGeoTranslation(0.,3.1,-1.725));
 545    iroc->AddNode(ppv,1,new TGeoTranslation(0.,4.59,-1.725));
 546    tga =(23.3521-14.5974)/49.65;
 547    Double_t xx = 24.825*tga+14.5974-0.6;
 548    iroc->AddNode(f1v,1,new TGeoTranslation(-xx,5.39,-1.725));
 549    iroc->AddNode(f2v,1,new TGeoTranslation(xx,5.39,-1.725));
 550    //
 551    // OROC
 552    //
 553    TGeoTrd1 *obody = new TGeoTrd1(22.2938,40.5084,4.19,51.65);
 554    TGeoVolume *obdv = new TGeoVolume("TPC_OROCB",obody,m3);
 555    TGeoTrd1 *oemp = new TGeoTrd1(20.2938,38.5084,3.89,49.65);
 556    TGeoVolume *oempv = new TGeoVolume("TPC_OROCE",oemp,m1);
 557    obdv->AddNode(oempv,1,new TGeoTranslation(0.,-0.3,0.));
 558    //horizontal bars
 559    tga=(38.5084-20.2938)/99.3;
 560    xmin=tga*10.2+20.2938;
 561    xmax=tga*10.6+20.2938;
 562    TGeoTrd1 *ob1 = new TGeoTrd1(xmin,xmax,2.915,0.2);
 563    TGeoVolume *ob1v = new TGeoVolume("TPC_ORB1",ob1,m3);
 564    //
 565    xmin=22.55*tga+20.2938;
 566    xmax=24.15*tga+20.2938;
 567    TGeoTrd1 *ob2 = new TGeoTrd1(xmin,xmax,2.915,0.8);
 568    TGeoVolume *ob2v = new TGeoVolume("TPC_ORB2",ob2,m3);
 569    //
 570    xmin=36.1*tga+20.2938;
 571    xmax=36.5*tga+20.2938;
 572    TGeoTrd1 *ob3 = new TGeoTrd1(xmin,xmax,2.915,0.2);
 573    TGeoVolume *ob3v = new TGeoVolume("TPC_ORB3",ob3,m3);
 574    //
 575    xmin=49.0*tga+20.2938;
 576    xmax=50.6*tga+20.2938;
 577    TGeoTrd1 *ob4 = new TGeoTrd1(xmin,xmax,2.915,0.8);
 578    TGeoVolume *ob4v = new TGeoVolume("TPC_ORB4",ob4,m3);
 579    //
 580    xmin=63.6*tga+20.2938;
 581    xmax=64.0*tga+20.2938;
 582    TGeoTrd1 *ob5 = new TGeoTrd1(xmin,xmax,2.915,0.2);
 583    TGeoVolume *ob5v = new TGeoVolume("TPC_ORB5",ob5,m3);
 584    //
 585    xmin=75.5*tga+20.2938;
 586    xmax=77.15*tga+20.2938;
 587    TGeoTrd1 *ob6 = new TGeoTrd1(xmin,xmax,2.915,0.8);
 588    TGeoVolume *ob6v = new TGeoVolume("TPC_ORB6",ob6,m3);
 589    //
 590    xmin=88.7*tga+20.2938;
 591    xmax=89.1*tga+20.2938;
 592    TGeoTrd1 *ob7 = new TGeoTrd1(xmin,xmax,2.915,0.2);
 593    TGeoVolume *ob7v = new TGeoVolume("TPC_ORB7",ob7,m3);
 594    //
 595    oempv->AddNode(ob1v,1,new TGeoTranslation(0.,0.975,-39.25));
 596    oempv->AddNode(ob2v,1,new TGeoTranslation(0.,0.975,-26.3));
 597    oempv->AddNode(ob3v,1,new TGeoTranslation(0.,0.975,-13.35));
 598    oempv->AddNode(ob4v,1,new TGeoTranslation(0.,0.975,0.15));
 599    oempv->AddNode(ob5v,1,new TGeoTranslation(0.,0.975,14.15));
 600    oempv->AddNode(ob6v,1,new TGeoTranslation(0.,0.975,26.7));
 601    oempv->AddNode(ob7v,1,new TGeoTranslation(0.,0.975,39.25));
 602    // vertical bars
 603    TGeoBBox *ob8 = new TGeoBBox(0.8,2.915,5.1);
 604    TGeoBBox *ob9 = new TGeoBBox(0.8,2.915,5.975);
 605    TGeoBBox *ob10 = new TGeoBBox(0.8,2.915,5.775);
 606    TGeoBBox *ob11 = new TGeoBBox(0.8,2.915,6.25);
 607    TGeoBBox *ob12 = new TGeoBBox(0.8,2.915,6.5);
 608    //
 609    TGeoVolume *ob8v = new TGeoVolume("TPC_ORB8",ob8,m3);
 610    TGeoVolume *ob9v = new TGeoVolume("TPC_ORB9",ob9,m3);
 611    TGeoVolume *ob10v = new TGeoVolume("TPC_ORB10",ob10,m3);
 612    TGeoVolume *ob11v = new TGeoVolume("TPC_ORB11",ob11,m3);
 613    TGeoVolume *ob12v = new TGeoVolume("TPC_ORB12",ob12,m3);
 614    //
 615    oempv->AddNode(ob8v,1,new TGeoTranslation(0.,0.975,-44.55));
 616    oempv->AddNode(ob8v,2,new TGeoTranslation(0.,0.975,44.55));
 617    oempv->AddNode(ob9v,1,new TGeoTranslation(0.,0.975,-33.075));
 618    oempv->AddNode(ob9v,2,new TGeoTranslation(0.,0.975,-19.525));
 619    oempv->AddNode(ob10v,1,new TGeoTranslation(0.,0.975,20.125));
 620    oempv->AddNode(ob10v,2,new TGeoTranslation(0.,0.975,33.275));
 621    oempv->AddNode(ob11v,1,new TGeoTranslation(0.,0.975,-6.9));
 622    oempv->AddNode(ob12v,1,new TGeoTranslation(0.,0.975,7.45));
 623    //
 624    // holes for connectors
 625    //
 626    fileName = gSystem->Getenv("ALICE_ROOT");
 627    fileName += "/TPC/conn_oroc.dat";
 628    in.open(fileName.Data(), ios_base::in); // asci file
 629    for(Int_t i =0;i<78;i++){
 630       Double_t y =3.89;
 631       Double_t x,z,ang;
 632       Double_t x1,z1,x2,z2;
 633       in>>x>>z>>ang;
 634       Double_t xr = 4.7*TMath::Sin(ang*TMath::DegToRad());
 635       Double_t zr = 4.7*TMath::Cos(ang*TMath::DegToRad());
 636       //
 637       x1=xr+x; x2=-xr+x; z1=zr+z; z2 = -zr+z;
 638       //
 639       TGeoRotation *rr = new TGeoRotation();
 640       rr->RotateY(ang);
 641       z1-=54.95;
 642       z2-=54.95;
 643       TGeoCombiTrans *trans1 = new TGeoCombiTrans("trans1",x1,y,z1,rr);
 644       TGeoCombiTrans *trans2 = new TGeoCombiTrans("trans2",x2,y,z2,rr);
 645       obdv->AddNode(connv,i+1,trans1);
 646       obdv->AddNode(connv,i+79,trans2);
 647    }
 648    in.close();
 649    // cap
 650    new TGeoTrd1("ocap",23.3874,43.5239,1.09,57.1);
 651    new TGeoTrd1("ohole",22.2938,40.5084,1.09,51.65);
 652    TGeoTranslation *tr5 = new TGeoTranslation("tr5",0.,0.,-2.15);
 653    tr5->RegisterYourself();
 654    TGeoCompositeShape *oc = new TGeoCompositeShape("ocap-ohole:tr5");
 655    TGeoVolume *ocv = new TGeoVolume("TPC_ORCAP",oc,m3);
 656    //
 657    // pad plane and wire fixations
 658    //
 659    TGeoTrd1 *opp = new TGeoTrd1(23.3874,43.5239,0.3,57.1);
 660    TGeoVolume *oppv = new TGeoVolume("TPC_ORPP",opp,m4);
 661    //
 662    tga=(43.5239-23.3874)/114.2;
 663    TGeoPara *f3 = new TGeoPara(.7,.6,57.1,0.,-10.,0.);
 664    TGeoPara *f4 = new TGeoPara(.7,.6,57.1,0.,10.,0.);
 665    xx = 57.1*tga+23.3874-0.7;
 666    TGeoVolume *f3v = new TGeoVolume("TPC_ORF1",f3,m4);
 667    TGeoVolume *f4v = new TGeoVolume("TPC_ORF2",f4,m4);
 668    //
 669    TGeoVolumeAssembly *oroc = new TGeoVolumeAssembly("TPC_OROC");
 670    //
 671    oroc->AddNode(obdv,1);
 672    oroc->AddNode(ocv,1,new TGeoTranslation(0.,3.1,2.15));
 673    oroc->AddNode(oppv,1,new TGeoTranslation(0.,4.49,2.15));
 674    oroc->AddNode(f3v,1,new TGeoTranslation(-xx,5.39,2.15));
 675    oroc->AddNode(f4v,1,new TGeoTranslation(xx,5.39,2.15));
 676    //
 677    // now iroc and oroc are placed into a sector...
 678    //
 679    TGeoVolumeAssembly *secta = new TGeoVolumeAssembly("TPC_SECT"); // a-side
 680    TGeoVolumeAssembly *sectc = new TGeoVolumeAssembly("TPC_SECT"); // c-side
 681    TGeoRotation rot1("rot1",90.,90.,0.);
 682    TGeoRotation rot2("rot2");
 683    rot2.RotateY(10.);
 684    TGeoRotation *rot = new TGeoRotation("rot");
 685    *rot=rot1*rot2;
 686    //
 687    Double_t x0,y0;
 688    x0=110.2*TMath::Cos(openingAngle);
 689    y0=110.2*TMath::Sin(openingAngle);
 690    TGeoCombiTrans *combi1a = new TGeoCombiTrans("combi1",x0,y0,1.09+0.195,rot); //a-side
 691    TGeoCombiTrans *combi1c = new TGeoCombiTrans("combi1",x0,y0,1.09+0.222,rot); //c-side
 692    x0=188.45*TMath::Cos(openingAngle);
 693    y0=188.45*TMath::Sin(openingAngle);
 694    TGeoCombiTrans *combi2a = new TGeoCombiTrans("combi2",x0,y0,0.99+0.195,rot); //a-side
 695    TGeoCombiTrans *combi2c = new TGeoCombiTrans("combi2",x0,y0,0.99+0.222,rot); //c-side
 696    //
 697    //
 698    // A-side
 699    //
 700    secta->AddNode(ch,1);
 701    secta->AddNode(iroc,1,combi1a);
 702    secta->AddNode(oroc,1,combi2a);
 703    //
 704    // C-side
 705    //
 706    sectc->AddNode(ch,1);
 707    sectc->AddNode(iroc,1,combi1c);
 708    sectc->AddNode(oroc,1,combi2c);
 709    //
 710    // now I try to make  wheels...
 711    //
 712    TGeoVolumeAssembly *wheela = new TGeoVolumeAssembly("TPC_ENDCAP");
 713    TGeoVolumeAssembly *wheelc = new TGeoVolumeAssembly("TPC_ENDCAP");
 714    //
 715    for(Int_t i =0;i<18;i++){
 716      Double_t phi = (20.*i);
 717      TGeoRotation *r = new TGeoRotation();
 718      r->RotateZ(phi);
 719      wheela->AddNode(secta,i+1,r);
 720      wheelc->AddNode(sectc,i+1,r);
 721
 722    }
 723    // wheels in the drift volume!
 724
 725    TGeoCombiTrans *combi3 = new TGeoCombiTrans("combi3",0.,0.,256.6,ref);
 726    v9->AddNode(wheela,1,combi3);
 727    v9->AddNode(wheelc,2,new TGeoTranslation(0.,0.,-256.6));
 728    //_____________________________________________________________
 729    // service support wheel
 730    //_____________________________________________________________
 731   TGeoPgon *sw = new TGeoPgon(0.,20.,1,2);
 732   sw->DefineSection(0,-4.,80.5,251.75);
 733   sw->DefineSection(1,4.,80.5,251.75);
 734   TGeoVolume *swv = new TGeoVolume("TPC_SWSEG",sw,m3); //Al
 735   //
 736   thick=1.;
 737   shift = thick/TMath::Sin(openingAngle);
 738   TGeoPgon *sh = new TGeoPgon(0.,20.,1,2);
 739   sh->DefineSection(0,-4.,81.5-shift,250.75-shift);
 740   sh->DefineSection(1,4.,81.5-shift,250.75-shift);
 741   TGeoVolume *shv = new TGeoVolume("TPC_SWS1",sh,m1); //Air
 742   //
 743   TGeoMedium *m9 =  gGeoManager->GetMedium("TPC_Si");
 744   TGeoPgon *el = new TGeoPgon(0.,20.,1,2);
 745   el->DefineSection(0,-1.872,81.5-shift,250.75-shift);
 746   el->DefineSection(1,1.872,81.5-shift,250.75-shift);
 747   TGeoVolume *elv = new TGeoVolume("TPC_ELEC",el,m9); //Si
 748   //
 749   shv->AddNode(elv,1);
 750   //
 751   //
 752   ys = shift*TMath::Sin(openingAngle);
 753   xs = shift*TMath::Cos(openingAngle);
 754   swv->AddNode(shv,1,new TGeoTranslation(xs,ys,0.));
 755   // cover
 756   TGeoPgon *co = new TGeoPgon(0.,20.,1,2);
 757   co->DefineSection(0,-0.5,77.,255.25);
 758   co->DefineSection(1,0.5,77.,255.25);
 759   TGeoVolume *cov = new TGeoVolume("TPC_SWC1",co,m3);//Al
 760   // hole in a cover
 761   TGeoPgon *coh = new TGeoPgon(0.,20.,1,2);
 762   shift=4./TMath::Sin(openingAngle);
 763   coh->DefineSection(0,-0.5,85.-shift,247.25-shift);
 764   coh->DefineSection(1,0.5,85.-shift,247.25-shift);
 765   //
 766   TGeoVolume *cohv = new TGeoVolume("TPC_SWC2",coh,m1);
 767   //
 768   ys = shift*TMath::Sin(openingAngle);
 769   xs = shift*TMath::Cos(openingAngle);
 770   cov->AddNode(cohv,1,new TGeoTranslation(xs,ys,0.));
 771   //
 772   // Sector as an Assembly
 773   //
 774   TGeoVolumeAssembly *swhs = new TGeoVolumeAssembly("TPC_SSWSEC");
 775   swhs->AddNode(swv,1);
 776   swhs->AddNode(cov,1,new TGeoTranslation(0.,0.,-4.5));
 777   swhs->AddNode(cov,2,new TGeoTranslation(0.,0.,4.5));
 778   //
 779   // SSW as an Assembly of sectors
 780   //
 781  TGeoVolumeAssembly *swheel = new TGeoVolumeAssembly("TPC_SSWHEEL");
 782    for(Int_t i =0;i<18;i++){
 783      Double_t phi = (20.*i);
 784      TGeoRotation *r = new TGeoRotation();
 785      r->RotateZ(phi);
 786      swheel->AddNode(swhs,i+1,r);
 787    }
 788    v1->AddNode(swheel,1,new TGeoTranslation(0.,0.,-284.6));
 789    v1->AddNode(swheel,2,new TGeoTranslation(0.,0.,284.6));
 790
 791    // sensitive strips - strip "0" is always set
 792    // conditional
 793    Int_t totrows;
 794    totrows = fTPCParam->GetNRowLow() + fTPCParam->GetNRowUp();
 795    Double_t *upar;
 796    upar=NULL;
 797    gGeoManager->Volume("TPC_Strip","PGON",m5->GetId(),upar);
 798    upar=new Double_t [10];
 799    upar[0]=0.;
 800    upar[1]=360.;
 801    upar[2]=18.;
 802    upar[3]=2.;
 803    //
 804    upar[4]=-124.8;
 805    upar[7]=124.8;
 806
 807    Double_t rlow=fTPCParam->GetPadRowRadiiLow(0);
 808
 809    upar[5]=rlow;
 810    upar[6]=rlow+.01;
 811    upar[8]=upar[5];
 812    upar[9]=upar[6];
 813    //
 814    gGeoManager->Node("TPC_Strip",1,"TPC_Drift",0.,0.,124.82,0,kTRUE,upar,10);
 815    gGeoManager->Node("TPC_Strip",totrows+1,
 816                      "TPC_Drift",0.,0.,-124.82,0,kTRUE,upar,10);
 817    //
 818    // now, strips optionally
 819    //
 820    if(fSens){
 821      //lower sectors
 822      for(Int_t i=2;i<fTPCParam->GetNRowLow()+1;i++){
 823        rlow=fTPCParam->GetPadRowRadiiLow(i-1);
 824        upar[5]=rlow;
 825        upar[6]=rlow+.01;
 826        upar[8]=upar[5];
 827        upar[9]=upar[6];
 828        gGeoManager->Node("TPC_Strip",i,
 829                          "TPC_Drift",0.,0.,124.82,0,kTRUE,upar,10);
 830        gGeoManager->Node("TPC_Strip",totrows+i,
 831                          "TPC_Drift",0.,0.,-124.82,0,kTRUE,upar,10);
 832      }
 833      //upper sectors
 834      for(Int_t i=1;i<fTPCParam->GetNRowUp()+1;i++){
 835        rlow=fTPCParam->GetPadRowRadiiUp(i-1);
 836        upar[5]=rlow;
 837        upar[6]=rlow+.01;
 838        upar[8]=upar[5];
 839        upar[9]=upar[6];
 840        gGeoManager->Node("TPC_Strip",i+fTPCParam->GetNRowLow(),
 841                          "TPC_Drift",0.,0.,124.82,0,kTRUE,upar,10);
 842        gGeoManager->Node("TPC_Strip",totrows+i+fTPCParam->GetNRowLow(),
 843                          "TPC_Drift",0.,0.,-124.82,0,kTRUE,upar,10);
 844      }
 845    }//strips
 846   //----------------------------------------------------------
 847   // TPc Support Rods - MAKROLON
 848   //----------------------------------------------------------
 849   TGeoMedium *m6=gGeoManager->GetMedium("TPC_Makrolon");
 850   TGeoMedium *m7=gGeoManager->GetMedium("TPC_Cu");
 851   TGeoMedium *m10 =  gGeoManager->GetMedium("TPC_Alumina");
 852   TGeoMedium *m11 =  gGeoManager->GetMedium("TPC_Peek");
 853   TGeoMedium *m12 =  gGeoManager->GetMedium("TPC_Water");
 854   // upper and lower rods differ in length!
 855   delete [] upar;
 856   upar=NULL;
 857   gGeoManager->Volume("TPC_Rod","TUBE",m6->GetId(),upar);
 858   upar=new Double_t [3];
 859   upar[0]=1.8;
 860   upar[1]=2.2;
 861
 862   //
 863   //HV rods - makrolon + 0.58cm (diameter) Cu
 864   TGeoTube *hvr = new TGeoTube(0.,2.2,126.64);
 865   TGeoTube *hvc = new TGeoTube(0.,0.29,126.64);
 866   //
 867   TGeoVolume *hvrv = new TGeoVolume("TPC_HV_Rod",hvr,m6);
 868   TGeoVolume *hvcv = new TGeoVolume("TPC_HV_Cable",hvc,m7);
 869   hvrv->AddNode(hvcv,1);
 870   //
 871   // resistor rods
 872   //
 873   TGeoTube *cri = new TGeoTube(0.,0.45,126.64); //inner
 874   TGeoTube *cro = new TGeoTube(0.,0.45,126.54); //outer
 875   TGeoTube *cwi = new TGeoTube(0.,0.15,126.64); // water inner
 876   TGeoTube *cwo = new TGeoTube(0.,0.15,126.54); // water outer
 877   //
 878   TGeoVolume *criv = new TGeoVolume("TPC_CR_I",cri,m10);
 879   TGeoVolume *crov = new TGeoVolume("TPC_CR_O",cro,m10);
 880   TGeoVolume *cwiv = new TGeoVolume("TPC_W_I",cwi,m11);
 881   TGeoVolume *cwov = new TGeoVolume("TPC_W_O",cwo,m11);
 882   //
 883   // ceramic rod with water
 884   //
 885   criv->AddNode(cwiv,1);
 886   crov->AddNode(cwov,1);
 887   //
 888   TGeoTube *pri =new TGeoTube(0.2,0.35,126.64); //inner
 889   TGeoTube *pro = new TGeoTube(0.2,0.35,126.54); //outer
 890   //
 891   // peek rod
 892   //
 893   TGeoVolume *priv = new TGeoVolume("TPC_PR_I",pri,m12);
 894   TGeoVolume *prov = new TGeoVolume("TPC_PR_O",pro,m12);
 895   //
 896   // resistor rods assembly
 897   //
 898    TGeoRotation* rotr = new TGeoRotation("rotr");
 899    rotr->RotateZ(-21.);
 900   //
 901   TGeoTube *rri = new TGeoTube(1.8,2.2,126.64);//inner
 902   TGeoTube *rro = new TGeoTube(1.8,2.2,126.54);//inner
 903   //
 904   TGeoVolume *rriv = new TGeoVolume("TPC_RR_I",rri,m6);
 905   TGeoVolume *rrov = new TGeoVolume("TPC_RR_O",rro,m6);
 906   //
 907   TGeoVolumeAssembly *rrin = new TGeoVolumeAssembly("TPC_RROD_I");
 908   TGeoVolumeAssembly *rrou = new TGeoVolumeAssembly("TPC_RROD_O");
 909   rrin->AddNode(rriv,1);
 910   rrin->AddNode(criv,1,new TGeoTranslation(0.5,0.866, 0.));
 911   rrin->AddNode(criv,2,new TGeoTranslation(0.5,-0.866, 0.));
 912   rrin->AddNode(priv,1);
 913   //
 914   rrou->AddNode(rrov,1);
 915   rrou->AddNode(crov,1,new TGeoTranslation(0.5,0.866, 0.));
 916   rrou->AddNode(crov,2,new TGeoTranslation(0.5,-0.866, 0.));
 917   rrou->AddNode(prov,1);
 918   //
 919   for(Int_t i=0;i<18;i++){
 920     Double_t angle,x,y;
 921     Double_t z,r;
 922     angle=TMath::DegToRad()*20.*(Double_t)i;
 923     r=81.5;
 924     x=r * TMath::Cos(angle);
 925     y=r * TMath::Sin(angle);
 926     upar[2]=126.64; //lower
 927     z= 126.96;
 928     //
 929     if(i==3){
 930         v9->AddNode(rrin,1,new TGeoCombiTrans(x,y, z, rotr)); //A
 931         v9->AddNode(rrin,2,new TGeoCombiTrans(x,y,-z, rotr)); //C
 932     }
 933     else {
 934       gGeoManager->Node("TPC_Rod",i+1,"TPC_Drift",x,y,z,0,kTRUE,upar,3);//shaft
 935       gGeoManager->Node("TPC_Rod",i+19,"TPC_Drift",x,y,-z,0,kTRUE,upar,3);//muon
 936     }
 937
 938
 939     //
 940     r=254.25;
 941     x=r * TMath::Cos(angle);
 942     y=r * TMath::Sin(angle);
 943     upar[2]=126.54; //upper
 944     z=127.06;
 945     //
 946     if(i==15){
 947       //v9->AddNode(hvrv,1,new TGeoTranslation(x,y,z));//A-side only
 948         v9->AddNode(hvrv,1,new TGeoTranslation(x,y,127.14));//A-side only
 949         gGeoManager->Node("TPC_Rod",i+55,"TPC_Drift",x,y,-z,0,kTRUE,upar,3);
 950     }
 951     else if(i==11){
 952         v9->AddNode(rrou,1,new TGeoCombiTrans(x,y, z, rotr));  //A
 953         v9->AddNode(rrou,2,new TGeoCombiTrans(x,y,-z, rotr));  //C
 954     }
 955     else{
 956     //
 957       gGeoManager->Node("TPC_Rod",i+37,"TPC_Drift",x,y,z,0,kTRUE,upar,3);
 958       gGeoManager->Node("TPC_Rod",i+55,"TPC_Drift",x,y,-z,0,kTRUE,upar,3);
 959     }
 960   }
 961
 962   delete [] upar;
 963
 964   TGeoVolume *alice = gGeoManager->GetVolume("ALIC");
 965   alice->AddNode(v1,1);
 966
 967 } // end of function
 968
 969 //_____________________________________________________________________________
 970 void AliTPCv2::AddAlignableVolumes() const
 971 {
 972   //
 973   // Create entries for alignable volumes associating the symbolic volume
 974   // name with the corresponding volume path. Needs to be syncronized with
 975   // eventual changes in the geometry.
 976   //
 977   SetInnerChambersAlignable();
 978   SetOuterChambersAlignable();
 979 }
 980
 981 //_____________________________________________________________________________
 982 void AliTPCv2::SetInnerChambersAlignable() const
 983 {
 984   //
 985   AliGeomManager::ELayerID idTPC1 = AliGeomManager::kTPC1;
 986   Int_t modUID, modnum = 0;
 987   TString vpstr1 = "ALIC_1/TPC_M_1/TPC_Drift_1/TPC_ENDCAP_1/TPC_SECT_";
 988   TString vpstr2 = "ALIC_1/TPC_M_1/TPC_Drift_1/TPC_ENDCAP_2/TPC_SECT_";
 989   TString vpappend = "/TPC_IROC_1";
 990   TString snstr1="TPC/EndcapA/Sector";
 991   TString snstr2="TPC/EndcapC/Sector";
 992   TString snappend="/InnerChamber";
 993   TString volpath, symname;
 994
 995   for(Int_t cnt=1; cnt<=18; cnt++){
 996     modUID = AliGeomManager::LayerToVolUID(idTPC1,modnum++);
 997     volpath = vpstr1;
 998     volpath += cnt;
 999     volpath += vpappend;
1000     symname = snstr1;
1001     symname += cnt;
1002     symname += snappend;
1003     if(!gGeoManager->SetAlignableEntry(symname.Data(),volpath.Data(),modUID))
1004       AliFatal(Form("Alignable entry %s not created. Volume path %s not valid", symname.Data(),volpath.Data()));
1005     TGeoPNEntry *alignableEntry = gGeoManager->GetAlignableEntryByUID(modUID);
1006     TGeoHMatrix* globMatrix = alignableEntry->GetGlobalOrig();
1007     TGeoHMatrix* matTtoL = fTPCParam->Tracking2LocalMatrix(globMatrix,cnt-1);
1008     alignableEntry->SetMatrix(matTtoL);
1009   }
1010
1011   for(Int_t cnt=1; cnt<=18; cnt++){
1012     modUID = AliGeomManager::LayerToVolUID(idTPC1,modnum++);
1013     volpath = vpstr2;
1014     volpath += cnt;
1015     volpath += vpappend;
1016     symname = snstr2;
1017     symname += cnt;
1018     symname += snappend;
1019     if(!gGeoManager->SetAlignableEntry(symname.Data(),volpath.Data(),modUID))
1020       AliFatal(Form("Alignable entry %s not created. Volume path %s not valid", symname.Data(),volpath.Data()));
1021     TGeoPNEntry *alignableEntry = gGeoManager->GetAlignableEntryByUID(modUID);
1022     TGeoHMatrix* globMatrix = alignableEntry->GetGlobalOrig();
1023     TGeoHMatrix* matTtoL = fTPCParam->Tracking2LocalMatrix(globMatrix,18+cnt-1);
1024     alignableEntry->SetMatrix(matTtoL);
1025   }
1026 }
1027
1028 //_____________________________________________________________________________
1029 void AliTPCv2::SetOuterChambersAlignable() const
1030 {
1031   //
1032   AliGeomManager::ELayerID idTPC2 = AliGeomManager::kTPC2;
1033   Int_t modUID, modnum = 0;
1034   TString vpstr1 = "ALIC_1/TPC_M_1/TPC_Drift_1/TPC_ENDCAP_1/TPC_SECT_";
1035   TString vpstr2 = "ALIC_1/TPC_M_1/TPC_Drift_1/TPC_ENDCAP_2/TPC_SECT_";
1036   TString vpappend = "/TPC_OROC_1";
1037   TString snstr1="TPC/EndcapA/Sector";
1038   TString snstr2="TPC/EndcapC/Sector";
1039   TString snappend="/OuterChamber";
1040   TString volpath, symname;
1041
1042   for(Int_t cnt=1; cnt<=18; cnt++){
1043     modUID = AliGeomManager::LayerToVolUID(idTPC2,modnum++);
1044     volpath = vpstr1;
1045     volpath += cnt;
1046     volpath += vpappend;
1047     symname = snstr1;
1048     symname += cnt;
1049     symname += snappend;
1050     if(!gGeoManager->SetAlignableEntry(symname.Data(),volpath.Data(),modUID))
1051       AliFatal(Form("Alignable entry %s not created. Volume path %s not valid", symname.Data(),volpath.Data()));
1052     TGeoPNEntry *alignableEntry = gGeoManager->GetAlignableEntryByUID(modUID);
1053     TGeoHMatrix* globMatrix = alignableEntry->GetGlobalOrig();
1054     TGeoHMatrix* matTtoL = fTPCParam->Tracking2LocalMatrix(globMatrix,36+cnt-1);
1055     alignableEntry->SetMatrix(matTtoL);
1056   }
1057
1058   for(Int_t cnt=1; cnt<=18; cnt++){
1059     modUID = AliGeomManager::LayerToVolUID(idTPC2,modnum++);
1060     volpath = vpstr2;
1061     volpath += cnt;
1062     volpath += vpappend;
1063     symname = snstr2;
1064     symname += cnt;
1065     symname += snappend;
1066     if(!gGeoManager->SetAlignableEntry(symname.Data(),volpath.Data(),modUID))
1067       AliFatal(Form("Alignable entry %s not created. Volume path %s not valid", symname.Data(),volpath.Data()));
1068     TGeoPNEntry *alignableEntry = gGeoManager->GetAlignableEntryByUID(modUID);
1069     TGeoHMatrix* globMatrix = alignableEntry->GetGlobalOrig();
1070     TGeoHMatrix* matTtoL = fTPCParam->Tracking2LocalMatrix(globMatrix,36+18+cnt-1);
1071     alignableEntry->SetMatrix(matTtoL);
1072   }
1073 }
1074
1075 //_____________________________________________________________________________
1076 void AliTPCv2::DrawDetector() const
1077 {
1078   //
1079   // Draw a shaded view of the Time Projection Chamber version 1
1080   //
1081
1082   // Set everything unseen
1083   gMC->Gsatt("*", "seen", -1);
1084   //
1085   // Set ALIC mother transparent
1086   gMC->Gsatt("ALIC","SEEN",0);
1087   //
1088   // Set the volumes visible
1089   //
1090
1091   gMC->Gsatt("TPC ","SEEN",0);
1092   gMC->Gsatt("TOIN","SEEN",1);
1093   gMC->Gsatt("TOIN","COLO",7);
1094   gMC->Gsatt("TOCV","SEEN",1);
1095   gMC->Gsatt("TOCV","COLO",4);
1096   gMC->Gsatt("TSA1","SEEN",0);
1097   gMC->Gsatt("TSA2","SEEN",0);
1098   gMC->Gsatt("TSA3","SEEN",0);
1099   gMC->Gsatt("TSA4","SEEN",0);
1100   gMC->Gsatt("TSA5","SEEN",0);
1101   gMC->Gsatt("TOFC","SEEN",1);
1102   gMC->Gsatt("TOFC","COLO",4);
1103   gMC->Gsatt("TSA6","SEEN",0);
1104   gMC->Gsatt("TSA7","SEEN",0);
1105   gMC->Gsatt("TSA8","SEEN",0);
1106   gMC->Gsatt("TIIN","SEEN",1);
1107   gMC->Gsatt("TIIN","COLO",7);
1108   gMC->Gsatt("TII1","SEEN",0);
1109   gMC->Gsatt("TIFC","SEEN",1);
1110   gMC->Gsatt("TIFC","COLO",4);
1111   gMC->Gsatt("TSA9","SEEN",0);
1112   gMC->Gsatt("TS10","SEEN",0);
1113   gMC->Gsatt("TS11","SEEN",0);
1114   gMC->Gsatt("TS12","SEEN",0);
1115   gMC->Gsatt("TS13","SEEN",0);
1116   gMC->Gsatt("TS14","SEEN",0);
1117   gMC->Gsatt("TICC","SEEN",0);
1118   gMC->Gsatt("TICM","SEEN",0);
1119   gMC->Gsatt("TS15","SEEN",0);
1120   gMC->Gsatt("TS16","SEEN",0);
1121   gMC->Gsatt("TS17","SEEN",0);
1122   gMC->Gsatt("TS18","SEEN",0);
1123   gMC->Gsatt("TS19","SEEN",0);
1124   gMC->Gsatt("TPJ1","SEEN",0);
1125   gMC->Gsatt("TPJ2","SEEN",0);
1126   gMC->Gsatt("TICS","SEEN",0);
1127   gMC->Gsatt("TDGN","SEEN",0);
1128   gMC->Gsatt("TIRC","SEEN",0);
1129   gMC->Gsatt("TIC1","SEEN",1);
1130   gMC->Gsatt("TIPP","SEEN",0);
1131   gMC->Gsatt("TIC3","SEEN",0);
1132   gMC->Gsatt("TRCE","SEEN",0);
1133   gMC->Gsatt("TPSC","SEEN",0);
1134   gMC->Gsatt("TPCC","SEEN",0);
1135   gMC->Gsatt("TORC","SEEN",0);
1136   gMC->Gsatt("TOPP","SEEN",0);
1137   gMC->Gsatt("TOC3","SEEN",0);
1138   gMC->Gsatt("TOC1","SEEN",1);
1139   gMC->Gsatt("TSSW","SEEN",1);
1140   gMC->Gsatt("TSWC","SEEN",1);
1141   gMC->Gsatt("TSSW","COLO",3);
1142   gMC->Gsatt("TSWC","COLO",3);
1143   gMC->Gsatt("TSCE","COLO",6);
1144   gMC->Gsatt("TSCE","SEEN",1);
1145   gMC->Gsatt("TWES","SEEN",0);
1146   gMC->Gsatt("TSWB","SEEN",0);
1147   gMC->Gsatt("TPEL","SEEN",0);
1148   gMC->Gsatt("TPMW","SEEN",1);
1149   gMC->Gsatt("TESR","SEEN",1);
1150   gMC->Gsatt("TPMW","COLO",12);
1151   gMC->Gsatt("TIC1","COLO",5);
1152   gMC->Gsatt("TOC1","COLO",5);
1153   gMC->Gsatt("TESB","SEEN",0);
1154   gMC->Gsatt("THVM","SEEN",1);
1155   gMC->Gsatt("THVM","COLO",11);
1156   gMC->Gsatt("THVH","SEEN",0);
1157   gMC->Gsatt("TPSR","SEEN",0);
1158   gMC->Gsatt("THVL","SEEN",0);
1159   gMC->Gsatt("THVC","SEEN",0);
1160   gMC->Gsatt("THVE","SEEN",0);
1161   gMC->Gsatt("THVR","SEEN",0);
1162   gMC->Gsatt("TPSS","SEEN",0);
1163   gMC->Gsatt("TPUS","SEEN",0);
1164   gMC->Gsatt("TPLS","SEEN",0);
1165
1166   //
1167   gMC->Gdopt("hide", "on");
1168   gMC->Gdopt("shad", "on");
1169   gMC->Gsatt("*", "fill", 7);
1170   gMC->SetClipBox(".");
1171   gMC->SetClipBox("TPMW",-300,300,-300,300,254.,270.);
1172   gMC->SetClipBox("TESR",-300,300,-300,300,254.,270.);
1173   gMC->SetClipBox("TSSW",-300,300,-300,300,283.,284.);
1174   gMC->SetClipBox("TSWC",-300,300,-300,300,283.,284.);
1175   gMC->SetClipBox("*", 0, 300, -300, 300, -290, 290);
1176   gMC->DefaultRange();
1177   gMC->Gdraw("alic", 40, 30, 0, 12, 9.5, .025, .025);
1178   gMC->Gdhead(1111, "Time Projection Chamber");
1179   gMC->Gdman(18, 4, "MAN");
1180   gMC->Gdopt("hide","off");
1181 }
1182
1183 //_____________________________________________________________________________
1184 void AliTPCv2::CreateMaterials()
1185 {
1186   //
1187   // Define materials for version 2 of the Time Projection Chamber
1188   //
1189
1190   AliTPC::CreateMaterials();
1191 }
1192
1193 //_____________________________________________________________________________
1194 void AliTPCv2::Init()
1195 {
1196   //
1197   // Initialises version 2 of the TPC after that it has been built
1198   //
1199
1200   Int_t *idtmed = fIdtmed->GetArray();
1201
1202   AliTPC::Init();
1203
1204
1205   fIdSens=gMC->VolId("TPC_Strip");  // one strip is always selected...
1206
1207   fIDrift=gMC->VolId("TPC_Drift");
1208   fSecOld=-100; // fake number
1209
1210   gMC->SetMaxNStep(-30000); // max. number of steps increased
1211
1212   if (fPrimaryIonisation) {
1213       gMC->Gstpar(idtmed[2],"PRIMIO_E", 20.77); // 1st ionisation potential
1214
1215       gMC->Gstpar(idtmed[2],"PRIMIO_N", 14.35);
1216       gMC->Gstpar(idtmed[2],"LOSS", 14); // specific energy loss
1217       gMC->Gstpar(idtmed[2],"STRA",4);
1218   } else {
1219       gMC->Gstpar(idtmed[2],"LOSS", 5); // specific energy loss
1220   }
1221
1222
1223   AliDebug(1,"*** TPC version 2 initialized ***");
1224   AliDebug(1,Form("Maximum number of steps = %d",gMC->GetMaxNStep()));
1225
1226   //
1227
1228 }
1229
1230 //_____________________________________________________________________________
1231 void AliTPCv2::StepManager()
1232 {
1233   //
1234   // Called for every step in the Time Projection Chamber
1235   //
1236
1237   //
1238   // parameters used for the energy loss calculations
1239   //
1240   const Float_t kprim = 14.35; // number of primary collisions per 1 cm
1241   const Float_t kpoti = 20.77e-9; // first ionization potential for Ne/CO2
1242   const Float_t kwIon = 35.97e-9; // energy for the ion-electron pair creation
1243   const Int_t   kMaxDistRef =15;     // maximal difference between 2 stored references
1244
1245   const Float_t kbig = 1.e10;
1246
1247   Int_t id,copy;
1248   Float_t hits[5];
1249   Int_t vol[2];
1250   TLorentzVector p;
1251
1252   vol[1]=0; // preset row number to 0
1253   //
1254   if (fPrimaryIonisation) gMC->SetMaxStep(kbig);
1255
1256   if(!gMC->IsTrackAlive()) return; // particle has disappeared
1257
1258   Float_t charge = gMC->TrackCharge();
1259
1260   if(TMath::Abs(charge)<=0.) return; // take only charged particles
1261
1262   // check the sensitive volume
1263
1264   id = gMC->CurrentVolID(copy); // vol ID and copy number (starts from 1!)
1265   if(id != fIDrift && id != fIdSens) return; // not in the sensitive folume
1266
1267   gMC->TrackPosition(p);
1268   Double_t r = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
1269   //
1270
1271   //
1272   Double_t angle = TMath::ACos(p[0]/r);
1273   angle = (p[1]<0.) ? TMath::TwoPi()-angle : angle;
1274   //
1275   // angular segment, it is not a real sector number...
1276   //
1277   Int_t sector=TMath::Nint((angle-fTPCParam->GetInnerAngleShift())/
1278                fTPCParam->GetInnerAngle());
1279   // rotate to segment "0"
1280   Float_t cos,sin;
1281   fTPCParam->AdjustCosSin(sector,cos,sin);
1282   Float_t x1=p[0]*cos + p[1]*sin;
1283   // check if within sector's limits
1284   if((x1>=fTPCParam->GetInnerRadiusLow()&&x1<=fTPCParam->GetInnerRadiusUp())
1285      ||(x1>=fTPCParam->GetOuterRadiusLow()&&x1<=fTPCParam->GetOuterRadiusUp())){
1286   // calculate real sector number...
1287   if (x1>fTPCParam->GetOuterRadiusLow()){
1288     sector = TMath::Nint((angle-fTPCParam->GetOuterAngleShift())/
1289              fTPCParam->GetOuterAngle())+fTPCParam->GetNInnerSector();
1290     if (p[2]<0)         sector+=(fTPCParam->GetNOuterSector()>>1);
1291   }
1292     else
1293       if (p[2]<0) sector+=(fTPCParam->GetNInnerSector()>>1);
1294   //
1295   // here I have a sector number
1296   //
1297
1298   vol[0]=sector;
1299
1300   static Double_t lastReferenceR=0;
1301   if (TMath::Abs(lastReferenceR-r)>kMaxDistRef){
1302     AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTPC);
1303     lastReferenceR = r;
1304   }
1305
1306   // check if change of sector
1307   if(sector != fSecOld){
1308     fSecOld=sector;
1309     // add track reference
1310     AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTPC);
1311   }
1312   // track is in the sensitive strip
1313   if(id == fIdSens){
1314     // track is entering the strip
1315     if (gMC->IsTrackEntering()){
1316       Int_t totrows = fTPCParam->GetNRowLow()+fTPCParam->GetNRowUp();
1317       vol[1] = (copy<=totrows) ? copy-1 : copy-1-totrows;
1318       // row numbers are autonomous for lower and upper sectors
1319       if(vol[0] > fTPCParam->GetNInnerSector()) {
1320         vol[1] -= fTPCParam->GetNRowLow();
1321       }
1322     //
1323       if(vol[0]<fTPCParam->GetNInnerSector()&&vol[1] == 0){
1324
1325         // lower sector, row 0, because Jouri wants to have this
1326
1327         gMC->TrackMomentum(p);
1328         hits[0]=p[0];
1329         hits[1]=p[1];
1330         hits[2]=p[2];
1331         hits[3]=0.; // this hit has no energy loss
1332         // Get also the track time for pileup simulation
1333         hits[4]=gMC->TrackTime();
1334
1335         AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber(), vol,hits);
1336       }
1337     //
1338
1339        gMC->TrackPosition(p);
1340        hits[0]=p[0];
1341        hits[1]=p[1];
1342        hits[2]=p[2];
1343        hits[3]=0.; // this hit has no energy loss
1344        // Get also the track time for pileup simulation
1345        hits[4]=gMC->TrackTime();
1346
1347        AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber(), vol,hits);
1348
1349     }
1350     else return;
1351   }
1352   //-----------------------------------------------------------------
1353   //  charged particle is in the sensitive drift volume
1354   //-----------------------------------------------------------------
1355   if(gMC->TrackStep() > 0) {
1356     Int_t nel=0;
1357     if (!fPrimaryIonisation) {
1358       nel = (Int_t)(((gMC->Edep())-kpoti)/kwIon) + 1;
1359     }
1360     else {
1361           Float_t edep = gMC->Edep();
1362           if (edep > 0.) nel = (Int_t)((gMC->Edep()*1.5)/kwIon) + 1;
1363     }
1364     nel=TMath::Min(nel,300); // 300 electrons corresponds to 10 keV
1365     //
1366     gMC->TrackPosition(p);
1367     hits[0]=p[0];
1368     hits[1]=p[1];
1369     hits[2]=p[2];
1370     hits[3]=(Float_t)nel;
1371
1372     // Add this hit
1373
1374     if (fHitType&&2){
1375       gMC->TrackMomentum(p);
1376       Float_t momentum = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
1377       Float_t precision =   (momentum>0.1) ? 0.002 :0.01;
1378       fTrackHits->SetHitPrecision(precision);
1379     }
1380
1381     // Get also the track time for pileup simulation
1382     hits[4]=gMC->TrackTime();
1383
1384     AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber(), vol,hits);
1385
1386   } // step>0
1387   } //within sector's limits
1388   // Stemax calculation for the next step
1389
1390   Float_t pp;
1391   TLorentzVector mom;
1392   // below is valid only for Geant3 (fPromaryIonisation not set)
1393   if(!fPrimaryIonisation){
1394     gMC->TrackMomentum(mom);
1395     Float_t ptot=mom.Rho();
1396     Float_t betaGamma = ptot/gMC->TrackMass();
1397
1398     Int_t pid=gMC->TrackPid();
1399     if((pid==kElectron || pid==kPositron) && ptot > 0.002)
1400       {
1401         pp = kprim*1.58; // electrons above 20 MeV/c are on the plateau!
1402       }
1403     else
1404       {
1405
1406         betaGamma = TMath::Max(betaGamma,(Float_t)7.e-3); // protection against too small bg
1407         pp=kprim*AliMathBase::BetheBlochAleph(betaGamma);
1408
1409     }
1410
1411     Double_t rnd = gMC->GetRandom()->Rndm();
1412
1413     gMC->SetMaxStep(-TMath::Log(rnd)/pp);
1414   }
1415
1416 }
1417
1418