Corrections of the hit recording algorithm.
[u/mrichter/AliRoot.git] / 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 /*
17 $Log$
18 Revision 1.25  2000/10/02 21:28:18  fca
19 Removal of useless dependecies via forward declarations
20
21 Revision 1.24  2000/08/28 10:02:30  kowal2
22 Corrected bug in the StepManager
23
24 Revision 1.23  2000/07/10 20:57:39  hristov
25 Update of TPC code and macros by M.Kowalski
26
27 Revision 1.22  2000/06/30 12:07:50  kowal2
28 Updated from the TPC-PreRelease branch
29
30 Revision 1.21.2.4  2000/06/26 07:39:42  kowal2
31 Changes to obey the coding rules
32
33 Revision 1.21.2.3  2000/06/25 08:38:41  kowal2
34 Splitted from AliTPCtracking
35
36 Revision 1.21.2.2  2000/06/16 12:58:13  kowal2
37 Changed parameter settings
38
39 Revision 1.21.2.1  2000/06/09 07:15:07  kowal2
40
41 Defaults loaded automatically (hard-wired)
42 Optional parameters can be set via macro called in the constructor
43
44 Revision 1.21  2000/05/15 10:00:30  kowal2
45 Corrected bug in the TPC geometry, thanks to Ivana Hrivnacova
46
47 Revision 1.20  2000/04/17 09:37:33  kowal2
48 removed obsolete AliTPCDigitsDisplay.C
49
50 Revision 1.19.8.2  2000/04/10 08:31:52  kowal2
51
52 Different geometry for different sectors
53 Updated readout chambers
54 Some modifications to StepManager by J.Belikov
55
56 Revision 1.19.8.1  2000/04/10 07:56:53  kowal2
57 Not used anymore - removed
58
59 Revision 1.19  1999/11/04 17:28:07  fca
60 Correct barrel part of HV Degrader
61
62 Revision 1.18  1999/10/14 16:52:08  fca
63 Only use PDG codes and not GEANT ones
64
65 Revision 1.17  1999/10/08 06:27:23  fca
66 Corrected bug in the HV degrader geometry, thanks to G.Tabary
67
68 Revision 1.16  1999/10/04 13:39:54  fca
69 Correct array index problem
70
71 Revision 1.15  1999/09/29 09:24:34  fca
72 Introduction of the Copyright and cvs Log
73
74 */
75
76 //
77 ///////////////////////////////////////////////////////////////////////////////
78 //                                                                           //
79 //  Time Projection Chamber version 2 -- detailed TPC and slow simulation    //
80 //                                                                           //
81 //Begin_Html
82 /*
83 <img src="picts/AliTPCv2Class.gif">
84 */
85 //End_Html
86 //                                                                           //
87 //                                                                           //
88 ///////////////////////////////////////////////////////////////////////////////
89 #include <stdlib.h>
90
91 #include <TMath.h>
92
93 #include "AliTPCv2.h"
94 #include "AliTPCDigitsArray.h"
95 #include "AliRun.h"
96 #include "AliMC.h"
97 #include "AliConst.h"
98 #include "AliPDG.h"
99 #include "AliTPCParam.h"
100 #include "AliTPCParamSR.h"
101
102 ClassImp(AliTPCv2)
103  
104 //_____________________________________________________________________________
105 AliTPCv2::AliTPCv2(const char *name, const char *title) :
106   AliTPC(name, title) 
107 {
108   //
109   // Standard constructor for Time Projection Chamber version 2
110   //
111   fIdSens=0;
112   fIdLSec=0;
113   fIdUSec=0;
114
115   SetBufferSize(128000);
116
117   SetGasMixt(2,20,10,-1,0.9,0.1,0.); // Ne-CO2 90-10
118
119   // Default sectors
120
121   SetSecAL(4);
122   SetSecAU(4);
123   SetSecLows(1,  2,  3, 19, 20, 21);
124   SetSecUps(37, 38, 39, 37+18, 38+18, 39+18, -1, -1, -1, -1, -1, -1);
125   SetSens(1); // sensitive strips set 
126
127   if (fTPCParam)
128      fTPCParam->Write(fTPCParam->GetTitle());
129 }
130  
131 //_____________________________________________________________________________
132 void AliTPCv2::CreateGeometry()
133 {
134   //
135   // Create the geometry of Time Projection Chamber version 2
136   //
137   //Begin_Html
138   /*
139     <img src="picts/AliTPC.gif">
140   */
141   //End_Html
142   //Begin_Html
143   /*
144     <img src="picts/AliTPCv2Tree.gif">
145   */
146   //End_Html
147
148
149   Int_t *idtmed = fIdtmed->GetArray();
150
151   Float_t dm[50];
152   Int_t idrotm[120];
153
154   Int_t nRotMat = 0;
155
156   Int_t i,ifl1=0;
157
158   // number of sectors
159
160   Int_t nInnerSector = fTPCParam->GetNInnerSector()/2;
161   Int_t nOuterSector = fTPCParam->GetNOuterSector()/2;
162   
163   // --------------------------------------------------- 
164   //        sector specification check 
165   // --------------------------------------------------- 
166   if (fSecAL >= 0) {
167     ifl1 = 0;
168     
169     for (i = 0; i < 6; ++i) {
170       if (fSecLows[i] >= 0 && fSecLows[i] < 2*nInnerSector) {
171         ifl1 = 1;
172         printf("*** SECTOR %d selected\n",fSecLows[i]);
173       }
174     }
175
176   } else {
177     printf("*** ALL LOWER SECTORS SELECTED ***\n");
178     ifl1 = 1;
179   }
180
181   if (ifl1 == 0) {
182     printf("*** ERROR: AT LEAST ONE LOWER SECTOR MUST BE SPECIFIED ***\n");
183     printf("!!! PROGRAM STOPPED !!!\n");
184     exit(1);
185   }
186
187   if (fSecAU >= 0) {
188     
189     for (i = 0; i < 12; ++i) {
190       if (fSecUps[i] > 2*nInnerSector-1 && 
191           fSecUps[i] < 2*(nInnerSector+nOuterSector)) {
192         printf("*** SECTOR %d selected\n",fSecUps[i]);
193       }
194     }
195     
196   } else {
197     printf("*** ALL UPPER SECTORS SELECTED ***\n");
198   }
199   
200  
201
202   //--------------------------------------------------------------------
203
204   //
205   //  Mother volume (Air) - all volumes will be positioned in it
206   //
207   
208   dm[0]=0.;
209   dm[1]=360.;
210   dm[2]=12.;
211
212   //
213  
214   dm[3]= -283.7;
215   dm[4]= 66.2;
216   dm[5]= 277.95;
217
218   //
219
220   dm[6]= -255.6;
221   dm[7]= 66.2;
222   dm[8]= 277.95;
223
224   //
225
226   dm[9]= -73.3;
227   dm[10]= 59.0;
228   dm[11]= 277.95;
229
230   //
231
232   dm[12]= -73.3;
233   dm[13]= 56.9;
234   dm[14]= 277.95;
235
236   //
237
238   dm[15]= -72.1;
239   dm[16]= 56.9;
240   dm[17]= 277.95;
241
242   //
243
244   dm[18]= -72.1;
245   dm[19]= 60.65;
246   dm[20]= 277.95;
247
248   //
249
250   dm[21]= 72.1;
251   dm[22]= 60.65;
252   dm[23]= 277.95;  
253
254   //
255
256   dm[24]= 72.1;
257   dm[25]= 56.9;
258   dm[26]= 277.95;
259
260   //
261
262   dm[27]= 73.3;
263   dm[28]= 56.9;
264   dm[29]= 277.95;
265
266   //
267
268   dm[30]= 73.3;
269   dm[31]= 60.65;
270   dm[32]= 277.95;
271
272   //
273
274   dm[33]= 250.4;
275   dm[34]= 66.0;
276   dm[35]= 277.95;
277
278   //
279
280   dm[36]= 283.7;
281   dm[37]= 66.0;
282   dm[38]= 277.95;
283
284
285   gMC->Gsvolu("TPC ","PCON",idtmed[0],dm,39);
286
287
288   //-------------------------------------------------------------------
289   //  Tpc Outer INsulator (CO2)
290   //-------------------------------------------------------------------
291
292   dm[0]= 0.;
293   dm[1]= 360.;
294   dm[2]= 6.;
295
296   //
297  
298   dm[3]= -253.6;
299   dm[4]= 258.;
300   dm[5]= 266.65;
301
302   //
303
304   dm[6]= -253.;
305   dm[7]= 258.;
306   dm[8]= 266.65;
307
308   dm[9]= -253.;
309   dm[10]= 258.;
310   dm[11]= 277.97;
311
312   dm[12]= 253.6;
313   dm[13]= 258.;
314   dm[14]= 277.97;
315
316   //
317
318   dm[15]= 253.6;
319   dm[16]= 265.2;
320   dm[17]= 277.95;
321
322   //
323
324   dm[18]= 255.6;
325   dm[19]= 265.2;
326   dm[20]= 277.95;
327
328
329   gMC->Gsvolu("TOIN","PCON",idtmed[3],dm,21);
330
331   //---------------------------------------------------------------
332   // shreds (G10) - TPC Rings
333   //---------------------------------------------------------------
334
335   gMC->Gsvolu("TPCR","TUBE",idtmed[12],dm,0);
336
337   dm[0]= 258.;
338   dm[1]= 266.65;
339   dm[2]= 0.3;
340
341   gMC->Gsposp("TPCR",1,"TOIN",0.,0.,-253.3,0,"ONLY",dm,3); // left bottom
342
343   //
344
345   dm[0]= 258.;
346   dm[1]= 270.9;
347   dm[2]= 0.3;
348
349   gMC->Gsposp("TPCR",2,"TOIN",0.,0.,253.3,0,"ONLY",dm,3); // right
350
351   //
352
353   dm[0]= 272.2;
354   dm[1]= 277.95;
355   dm[2]= 0.3;
356
357   gMC->Gsposp("TPCR",3,"TOIN",0.,0.,-250.7,0,"ONLY",dm,3); // left top
358
359   //----------------------------------------------------------------
360   // Tpc Outer Contaiment Vessel  
361   //  mother volume - Al, daughters - composite (sandwich)
362   //----------------------------------------------------------------
363   
364   dm[0]= 0.;
365   dm[1]= 360.;
366   dm[2]=5.;
367
368   //
369
370   dm[3]= -250.4;
371   dm[4]= 272.2;
372   dm[5]= 277.95;
373
374   //
375
376   dm[6]= -248.4;
377   dm[7]= 272.2;
378   dm[8]= 277.95;
379
380   //
381
382   dm[9]= 253.6;
383   dm[10]= 272.2;
384   dm[11]= 277.95;
385
386   //
387
388   dm[12]= 253.6;
389   dm[13]= 265.2;
390   dm[14]= 277.95;
391
392   // 
393
394   dm[15]= 255.6;
395   dm[16]= 265.2;
396   dm[17]= 277.95;
397
398   gMC->Gsvolu("TOCV","PCON",idtmed[4],dm,18);
399
400   // Daughter volumes
401
402   // Tpc SAndwich 1 - Al
403  
404   dm[0]= 274.81;
405   dm[1]= 277.95;
406   dm[2]= 251.7;
407
408   gMC->Gsvolu("TSA1","TUBE",idtmed[4],dm,3);
409
410   // Tpc SAndwich 2 - Tedlar
411
412   dm[0] += 5.e-3;
413   dm[1] -= 5.e-3;
414   
415   gMC->Gsvolu("TSA2","TUBE",idtmed[9],dm,3);
416
417   // Tpc SAndwich 3 - Kevlar
418
419   dm[0] += 5e-3;
420   dm[1] -= 5.e-3;
421
422   gMC->Gsvolu("TSA3","TUBE",idtmed[5],dm,3);
423
424   // Tpc SAndwich 4 - NOMEX honeycomb
425
426   dm[0] += 0.06;
427   dm[1] -= 0.06;
428
429   gMC->Gsvolu("TSA4","TUBE",idtmed[5],dm,3);  
430   
431   // 4->3->2->1->TOCV
432
433   gMC->Gspos("TSA4",1,"TSA3",0.,0.,0.,0,"ONLY");
434   gMC->Gspos("TSA3",1,"TSA2",0.,0.,0.,0,"ONLY");
435   gMC->Gspos("TSA2",1,"TSA1",0.,0.,0.,0,"ONLY");
436
437   gMC->Gspos("TSA1",1,"TOCV",0.,0.,2.6,0,"ONLY");
438
439   // TCOV-> TOIN
440
441   gMC->Gspos("TOCV",1,"TOIN",0.,0.,0.,0,"ONLY");
442
443   //-------------------------------------------------------
444   //  Tpc Outer Field Cage
445   //  mother volume - Al, daughters - composite (sandwich)
446   //-------------------------------------------------------
447
448   dm[0]=0.;
449   dm[1]=360.;
450   dm[2]=6.;
451
452   dm[3]= -253.;
453   dm[4]= 258.;
454   dm[5]= 277.95;
455
456   //
457
458   dm[6]= -251.;
459   dm[7]= 258.;
460   dm[8]= 277.95;
461
462   //
463  
464   dm[9]= -251.;
465   dm[10]= 258.;
466   dm[11]= 260.05;
467
468   //
469
470   dm[12]= 251.;
471   dm[13]= 258.;
472   dm[14]= 260.05;
473
474   //
475
476   dm[15]= 251.;
477   dm[16]= 258.;
478   dm[17]= 260.05;
479
480   //
481
482   dm[18]= 253.;
483   dm[19]= 258.;
484   dm[20]= 270.9;
485
486   gMC->Gsvolu("TOFC","PCON",idtmed[4],dm,21);  
487
488   // Daughter volumes 
489
490   // Tpc SAndwich 5 - Al
491
492   dm[0]= 258.;
493   dm[1]= 260.05;
494   dm[2]= 251.7;
495
496   gMC->Gsvolu("TSA5","TUBE",idtmed[4],dm,3);
497
498   // Tpc SAndwich 6 - Tedlar
499
500   dm[0] += 5.e-3;
501   dm[1] -= 5.e-3;
502
503   gMC->Gsvolu("TSA6","TUBE",idtmed[9],dm,3);
504
505   // Tpc SAndwich 7 - Kevlar
506
507   dm[0] += 5.e-3;
508   dm[1] -= 5.e-3;
509
510   gMC->Gsvolu("TSA7","TUBE",idtmed[5],dm,3);
511
512   // Tpc SAndwich 8 - NOMEX
513
514   dm[0] += 0.02;
515   dm[1] -= 0.02;
516
517   gMC->Gsvolu("TSA8","TUBE",idtmed[6],dm,3);    
518
519   // 8->7->6->5->TOFC
520
521   gMC->Gspos("TSA8",1,"TSA7",0.,0.,0.,0,"ONLY");
522   gMC->Gspos("TSA7",1,"TSA6",0.,0.,0.,0,"ONLY");
523   gMC->Gspos("TSA6",1,"TSA5",0.,0.,0.,0,"ONLY"); 
524
525   gMC->Gspos("TSA5",1,"TOFC",0.,0.,0.,0,"ONLY");
526
527   // TOFC->TOIN
528
529   gMC->Gspos("TOFC",1,"TOIN",0.,0.,0.,0,"ONLY"); 
530
531   // TOIN->TPC
532
533   gMC->Gspos("TOIN",1,"TPC ",0.,0.,0.,0,"ONLY");
534
535   //--------------------------------------------------------------------
536   // Tpc Inner INsulator (CO2)
537   //--------------------------------------------------------------------
538
539
540   dm[0]=0.;
541   dm[1]= 360.;
542   dm[2]= 15.;
543
544   //
545
546   dm[3]= -255.6;
547   dm[4]= 66.2;
548   dm[5]= 74.8;
549
550   //
551
552   Float_t tanL = (66.2-59.0)/(255.6-73.3); // tangent of the left cone part
553
554   dm[6]= -253.6;
555   dm[7]= 59.0+ (253.6-73.3)*tanL;
556   dm[8]= 74.8;
557
558   //
559
560   dm[9]= -253.6;
561   dm[10]= dm[7];
562   dm[11]= 79.2;
563
564   //
565
566   dm[12]= -73.3;
567   dm[13]= 59.0;
568   dm[14]= 79.2;
569
570   //
571
572   dm[15]= -73.3;
573   dm[16]= 56.9;
574   dm[17]= 79.2;
575
576   //
577
578   dm[18]= -72.1;
579   dm[19]= 59.6;
580   dm[20]= 79.2;
581
582   //
583
584   dm[21]= -72.1;
585   dm[22]= 60.65;
586   dm[23]= 79.2;
587
588   //
589
590   dm[24]= 72.1;
591   dm[25]= 60.65;
592   dm[26]= 79.2;  
593
594   //
595
596   dm[27]= 72.1;
597   dm[28]= 59.6;
598   dm[29]= 79.2;
599
600   //
601
602   dm[30]= 73.3;
603   dm[31]= 56.9;
604   dm[32]= 79.2;
605
606   //
607
608   dm[33]= 73.3;
609   dm[34]= 59.0;
610   dm[35]= 79.2;
611
612   //
613
614   dm[36]= 250.4;
615   dm[37]= 66.0;
616   dm[38]= 79.2;
617
618   //
619   
620   dm[39]= 253.0;
621   dm[40]= 66.0;
622   dm[41]= 79.2;
623
624   //
625
626   dm[42]= 253.0;
627   dm[43]= 75.3;
628   dm[44]= 79.2;
629
630   //
631
632   dm[45]= 253.6;
633   dm[46]= 75.3;
634   dm[47]= 79.2;
635
636   gMC->Gsvolu("TIIN","PCON",idtmed[3],dm,48);
637
638
639   //--------------------------------------------------------------------
640   //  Tpc Inner Containment vessel, Left part
641   //  mother volume - Al, daughter - composite (sandwich)
642   //--------------------------------------------------------------------
643
644   dm[0]= 0.;
645   dm[1]= 360.;
646   dm[2]= 8.;
647
648   //
649
650   dm[3]= -255.6;
651   dm[4]= 66.2;
652   dm[5]= 74.8;
653
654   //
655
656   Float_t cosL = 1./TMath::Sqrt(1.+tanL*tanL);
657   Float_t sandThick = 2.14; // cone composite thickness
658
659
660   //
661
662   dm[6]= -253.6;
663   dm[7]= 59.0 + (253.6-73.3)*tanL;
664   dm[8]= 74.8;
665
666   //
667
668   dm[9]= -253.6;
669   dm[10]= dm[7];
670   dm[11]= dm[7]+sandThick/cosL;
671
672   //
673
674   dm[12]= -75.6;
675   dm[13]= 59.0+(75.6-73.3)*tanL;
676   dm[14]= dm[13]+sandThick/cosL;
677
678   //
679
680   dm[15]= -75.6;
681   dm[16]= dm[13];
682   dm[17]= 60.65;
683
684   //
685
686   dm[18]= -73.3;
687   dm[19]= 59.0;
688   dm[20]= 60.65;
689
690   //
691
692   dm[21]= -73.3;
693   dm[22]= 56.9;
694   dm[23]= 60.65;
695
696   //
697
698   dm[24]= -72.1;
699   dm[25]= 56.9;
700   dm[26]= 60.65;
701
702   gMC->Gsvolu("TICL","PCON",idtmed[4],dm,27);
703
704   // Daughter volumes 
705
706   // Tpc SAndwich 9 - Al
707
708   dm[0]= 0.;
709   dm[1]= 360.;
710   dm[2]= 2.;
711
712   //
713
714   dm[3]= - 254.3;
715   dm[4]= 59.0+(254.3-73.3)*tanL;
716   dm[5]= dm[4]+sandThick/cosL;
717
718   //
719
720   dm[6]= -78.3;
721   dm[7]= 59.0+(78.3-73.3)*tanL;
722   dm[8]= dm[7]+sandThick/cosL;
723
724   //
725
726   gMC->Gsvolu("TSA9","PCON",idtmed[4],dm,9);
727
728   // Tpc SAndwich 10 - Tedlar
729
730   dm[4]+= 5.e-3/cosL;
731   dm[5]-= 5.e-3/cosL;
732
733   //
734
735   dm[7]+= 5.e-3/cosL;
736   dm[8]+= 5.e-3/cosL;
737
738   gMC->Gsvolu("TS10","PCON",idtmed[9],dm,9); 
739
740   // Tpc SAndwich 11 - Kevlar
741
742   dm[4]+= 5.e-3/cosL;
743   dm[5]-= 5.e-3/cosL;
744
745   //
746
747   dm[7]+= 5.e-3/cosL;
748   dm[8]+= 5.e-3/cosL;
749
750   gMC->Gsvolu("TS11","PCON",idtmed[5],dm,9); 
751
752   // Tpc SAndwich 12 - NOMEX
753
754   dm[4]+= 0.06/cosL;
755   dm[5]-= 0.06/cosL;
756
757   //
758
759   dm[7]+= 0.06/cosL;
760   dm[8]+= 0.06/cosL;
761
762   gMC->Gsvolu("TS12","PCON",idtmed[6],dm,9);   
763
764   // 12->11->10->9
765
766   gMC->Gspos("TS12",1,"TS11",0.,0.,0.,0,"ONLY");
767   gMC->Gspos("TS11",1,"TS10",0.,0.,0.,0,"ONLY");
768   gMC->Gspos("TS10",1,"TSA9",0.,0.,0.,0,"ONLY");
769
770   // TSA9->TICL
771
772   gMC->Gspos("TSA9",1,"TICL",0.,0.,0.,0,"ONLY");
773  
774   //--------------------------------------------------------------------
775   //  Tpc Inner Containment vessel, Right part
776   //  mother volume - Al, daughter - composite (sandwich)
777   //--------------------------------------------------------------------
778
779   dm[0]= 0.;
780   dm[1]= 360.;
781   dm[2]=8.;
782
783   //
784
785   dm[3]= 72.1;
786   dm[4]= 56.9;
787   dm[5]= 60.65;
788
789   //
790
791   dm[6]= 73.3;
792   dm[7]= 56.9;
793   dm[8]= 60.65;
794
795   //
796
797   dm[9]= 73.3;
798   dm[10]= 59.0;
799   dm[11]= 60.65;
800
801   //
802
803   Float_t tanR = (66.0-59.0)/(250.5-73.3); // to avoid accuracy problems
804   Float_t cosR = 1./TMath::Sqrt(1.+tanR*tanR); //as above
805
806   //
807
808   dm[12]= 75.6;
809   dm[13]= 59.0+(75.6-73.3)*tanR;
810   dm[14]= 60.65;
811
812   //
813
814   dm[15]= 75.6;
815   dm[16]= dm[13];
816   dm[17]= dm[16]+sandThick/cosR;
817
818   //
819
820   dm[18]= 248.4;
821   dm[19]= 59.0+(248.4-73.3)*tanR;
822   dm[20]= dm[19]+sandThick/cosR;
823
824   //
825
826   dm[21]= 248.4;
827   dm[22]= dm[19];
828   dm[23]= 70.2;
829
830   //
831
832   dm[24]= 250.4;
833   dm[25]= 66.0;
834   dm[26]= 70.2;
835
836   gMC->Gsvolu("TICR","PCON",idtmed[4],dm,27);
837
838
839
840   // Daughter volumes 
841
842   // Tpc SAndwich 13 - Al
843
844   dm[0]= 0.;
845   dm[1]= 360.;
846   dm[2]= 2.;
847
848   //
849
850   dm[3]= 78.3;
851   dm[4]= 59.0+(78.3-73.3)*tanR;
852   dm[5]= dm[4]+sandThick/cosR;
853
854   //
855
856   dm[6]= 249.1;
857   dm[7]= 59.0+(249.1-73.3)*tanR;
858   dm[8]= dm[7]+sandThick/cosR;
859
860   //
861
862   gMC->Gsvolu("TS13","PCON",idtmed[4],dm,9);
863
864   // Tpc SAndwich 14 - Tedlar
865
866   dm[4]+= 5.e-3/cosR;
867   dm[5]-= 5.e-3/cosR;
868
869   //
870
871   dm[7]+= 5.e-3/cosR;
872   dm[8]+= 5.e-3/cosR;
873
874   gMC->Gsvolu("TS14","PCON",idtmed[9],dm,9); 
875
876   // Tpc SAndwich 15 - Kevlar
877
878   dm[4]+= 5.e-3/cosR;
879   dm[5]-= 5.e-3/cosR;
880
881   //
882
883   dm[7]+= 5.e-3/cosR;
884   dm[8]+= 5.e-3/cosR;
885
886   gMC->Gsvolu("TS15","PCON",idtmed[5],dm,9); 
887
888   // Tpc SAndwich 16 - NOMEX
889
890   dm[4]+= 0.06/cosR;
891   dm[5]-= 0.06/cosR;
892
893   //
894
895   dm[7]+= 0.06/cosR;
896   dm[8]+= 0.06/cosR;
897
898   gMC->Gsvolu("TS16","PCON",idtmed[6],dm,9);   
899
900   // 16->15->14->13
901
902   gMC->Gspos("TS16",1,"TS15",0.,0.,0.,0,"ONLY");
903   gMC->Gspos("TS15",1,"TS14",0.,0.,0.,0,"ONLY");
904   gMC->Gspos("TS14",1,"TS13",0.,0.,0.,0,"ONLY");
905
906   // TS12->TICR
907
908   gMC->Gspos("TS13",1,"TICR",0.,0.,0.,0,"ONLY");
909
910   //------------------------------------------------------
911   // Tpc Inner Field Cage
912   // mother volume - Al, daughters - composite (sandwich)
913   //------------------------------------------------------
914
915   dm[0]= 0.;
916   dm[1]= 360.;
917   dm[2]=6.;
918
919   //
920
921   dm[3]= -253.0;
922   dm[4]= 70.7;
923   dm[5]= 79.2;
924
925   //
926
927   dm[6]= -251.0;
928   dm[7]= 70.7;
929   dm[8]= 79.2;
930
931   //
932
933   dm[9]= -251.0;
934   dm[10]= 77.15;
935   dm[11]= 79.2;
936
937   //
938   
939   dm[12]= 251.0;
940   dm[13]= 77.15;
941   dm[14]= 79.2;
942
943   //
944
945   dm[15]= 251.0;
946   dm[16]= 66.0;
947   dm[17]= 79.2;
948
949   //
950
951   dm[18]= 253.0;
952   dm[19]= 66.0;
953   dm[20]= 79.2;
954
955   gMC->Gsvolu("TIFC","PCON",idtmed[4],dm,21);
956
957   // Daughter volumes
958
959   // Tpc Sandwich 17 - Al
960
961   dm[0]= 77.15;
962   dm[1]= 79.2;
963   dm[2]= 251.7;
964
965   gMC->Gsvolu("TS17","TUBE",idtmed[4],dm,3);
966
967   // Tpc Sandwich 18 - Tedlar
968
969   dm[0]+= 5.e-3;
970   dm[1]-= 5.e-3;
971
972   gMC->Gsvolu("TS18","TUBE",idtmed[9],dm,3);
973
974   // Tpc Sandwich 19 - Kevlar
975
976   dm[0]+= 5.e-3;
977   dm[1]-= 5.e-3;
978
979   gMC->Gsvolu("TS19","TUBE",idtmed[5],dm,3);
980
981   // Tpc Sandwich 20 - NOMEX
982
983   dm[0]+= 0.06;
984   dm[1]-= 0.06;
985
986   gMC->Gsvolu("TS20","TUBE",idtmed[6],dm,3);
987
988   // 20->19->18->17
989
990   gMC->Gspos("TS20",1,"TS19",0.,0.,0.,0,"ONLY");
991   gMC->Gspos("TS19",1,"TS18",0.,0.,0.,0,"ONLY");
992   gMC->Gspos("TS18",1,"TS17",0.,0.,0.,0,"ONLY");
993
994   // TS17->TIFC
995
996   gMC->Gspos("TS17",1,"TIFC",0.,0.,0.,0,"ONLY");
997
998   // TPC Rings
999
1000   dm[0]= 70.7;
1001   dm[1]= 79.2;
1002   dm[2]= 0.3;
1003
1004   gMC->Gsposp("TPCR",4,"TIIN",0.,0.,-253.3,0,"ONLY",dm,3);
1005
1006   dm[0]= 66.0;
1007   dm[1]= 70.2;  
1008
1009   gMC->Gsposp("TPCR",5,"TIIN",0.,0.,250.7,0,"ONLY",dm,3);
1010
1011   dm[0]= 75.3;
1012   dm[1]= 79.2;  
1013
1014   gMC->Gsposp("TPCR",6,"TIIN",0.,0.,253.3,0,"ONLY",dm,3);  
1015
1016   // TICL->TIIN
1017
1018   gMC->Gspos("TICL",1,"TIIN",0.,0.,0.,0,"ONLY");
1019
1020   // TICR->TIIN
1021
1022   gMC->Gspos("TICR",1,"TIIN",0.,0.,0.,0,"ONLY");
1023
1024   // TIFC->TIIN
1025
1026   gMC->Gspos("TIFC",1,"TIIN",0.,0.,0.,0,"ONLY");
1027
1028   // Tpc Sandwich 21 - Al (central barrel)
1029
1030   dm[0]= 77.15;
1031   dm[1]= 79.2;
1032   dm[2]= 75.2;
1033
1034   gMC->Gsvolu("TS21","TUBE",idtmed[4],dm,3);
1035
1036   // Tpc Sandwich 22 - Tedlar (central barrel) 
1037
1038   dm[0]+= 5.e-3;
1039   dm[1]-= 5.e-3;
1040
1041   gMC->Gsvolu("TS22","TUBE",idtmed[9],dm,3); 
1042
1043   // Tpc Sandwich 23 - Kevlar (central barrel) 
1044
1045   dm[0]+= 5.e-3;
1046   dm[1]-= 5.e-3;
1047
1048   gMC->Gsvolu("TS23","TUBE",idtmed[5],dm,3); 
1049
1050   // Tpc Sandwich 24 - NOMEX (central barrel) 
1051
1052   dm[0]+= 0.02;
1053   dm[1]-= 0.02;
1054
1055   gMC->Gsvolu("TS24","TUBE",idtmed[6],dm,3); 
1056
1057   // 24->23->22->21
1058
1059   gMC->Gspos("TS24",1,"TS23",0.,0.,0.,0,"ONLY");
1060   gMC->Gspos("TS23",1,"TS22",0.,0.,0.,0,"ONLY");
1061   gMC->Gspos("TS22",1,"TS21",0.,0.,0.,0,"ONLY");
1062
1063   gMC->Gspos("TS21",1,"TIIN",0.,0.,0.,0,"ONLY");
1064
1065   // put everything into the TPC 
1066
1067   gMC->Gspos("TIIN",1,"TPC ",0.,0.,0.,0,"ONLY");
1068
1069
1070   //---------------------------------------------------------
1071   //  Tpc Dift Gas volume Nonsensitive (Ne-CO2 90/10)
1072   //  and its daughters (HV membrane, rods, readout chambers)
1073   //---------------------------------------------------------
1074
1075   dm[0]= 79.2;
1076   dm[1]= 258.0;
1077   dm[2]= 253.6;
1078
1079   gMC->Gsvolu("TDGN","TUBE",idtmed[1],dm,3);  // nonsensitive 
1080
1081     // sector opening angles
1082
1083   Float_t innerOpenAngle = fTPCParam->GetInnerAngle();
1084   Float_t outerOpenAngle = fTPCParam->GetOuterAngle();
1085
1086   // sector angle shift
1087
1088   Float_t innerAngleShift = fTPCParam->GetInnerAngleShift();
1089
1090   // All above parameters are identical for inner and outer
1091   // sectors. The distinction is kept for the historical reasons
1092   // and eventually will disappear.
1093
1094   Float_t tanAlpha = TMath::Tan(0.5*innerOpenAngle);
1095   Float_t cosAlpha = TMath::Sqrt(1.+tanAlpha*tanAlpha);
1096   Float_t space;
1097
1098   //-------------------------------------------------------------------------
1099   //   Tpc Inner Readout Chambers 
1100   //-------------------------------------------------------------------------
1101
1102   dm[0]= 14.483;
1103   dm[1]= 23.3345; 
1104   dm[2]= 1.6; // thickness
1105   dm[3]= 25.1;
1106
1107   gMC->Gsvolu("TIRC","TRD1",idtmed[4],dm,4);
1108
1109   // this volume will be positioned in the empty space
1110   // of the end-cap to avoid overlaps
1111
1112   dm[0]= 13.7305;
1113   dm[1]= 21.1895;
1114   dm[2]= 2.25;
1115   dm[3]= 21.15;
1116
1117   gMC->Gsvolu("TIC1","TRD1",idtmed[4],dm,4);
1118
1119   //------------------------------------------------
1120   // Tpc Inner readout chamber Pad Plane
1121   //------------------------------------------------
1122
1123   dm[0]= 14.483;
1124   dm[1]= 23.3345;
1125   dm[2]= 0.5;
1126   dm[3]= 25.1;
1127
1128   gMC->Gsvolu("TIPP","TRD1",idtmed[12],dm,4);
1129
1130   // 
1131
1132   dm[0] -= 1.218511934;
1133   dm[1] -= 1.218511934;
1134   dm[2] = 0.35;
1135
1136   gMC->Gsvolu("TIC3","TRD1",idtmed[1],dm,4);
1137
1138   gMC->Gspos("TIC3",1,"TIPP",0.,0.15,0.,0,"ONLY");
1139
1140   gMC->Gspos("TIPP",1,"TIRC",0.,1.1,0.,0,"ONLY");
1141
1142   //----------------------------------------------
1143   // Tpc Readout Chambers Empty spaces - for both
1144   // inner and outer sectors
1145   //----------------------------------------------
1146
1147   gMC->Gsvolu("TRCE","TRD1",idtmed[0],dm,0);
1148
1149   // Inner sector - 4 spaces
1150
1151
1152   dm[3] = 4.7625;
1153   dm[0] = 12.472;
1154
1155   Float_t rr = 90.52;
1156   Float_t zz;
1157
1158   zz= -12.7875;
1159   
1160   space = rr*tanAlpha-dm[0];
1161
1162   for(Int_t nsLow=0;nsLow<4;nsLow++){
1163
1164     rr += 9.525;
1165     dm[1]= rr*tanAlpha - space;  
1166
1167     dm[2]=0.8;
1168
1169     gMC->Gsposp("TRCE",nsLow+1,"TIRC",0.,-0.8,zz,0,"ONLY",dm,4);
1170
1171     //
1172
1173     dm[2]= 1.2;
1174
1175     gMC->Gsposp("TRCE",nsLow+5,"TIC1",0.,1.05,zz-2.1,0,"ONLY",dm,4);
1176
1177     rr += 0.4;
1178     dm[0] = rr*tanAlpha - space;
1179     zz += (0.4+9.525); 
1180
1181   }
1182
1183   dm[0]= 12.472;
1184   // dm[1] - this is the dm[1] from the previous TRCE
1185   dm[2]= 1.05;
1186   dm[3]= 19.65;
1187
1188   gMC->Gsposp("TRCE",9,"TIC1",0.,-1.2,0.,0,"ONLY",dm,4); 
1189
1190   //
1191   // TPc Space for Connectors
1192   //
1193
1194   dm[0]= .3;
1195   dm[1]= .3;
1196   dm[2]= 4.5;
1197
1198   gMC->Gsvolu("TPSC","BOX ",idtmed[0],dm,3);
1199
1200   // TPC Connectors
1201
1202   dm[0]= .25;
1203   dm[1]= .15;
1204   dm[2]= 3.75;
1205
1206   gMC->Gsvolu("TPCC","BOX ",idtmed[13],dm,3); 
1207
1208   gMC->Gspos("TPCC",1,"TPSC",0.,0.15,0.,0,"ONLY");
1209
1210   zz = -12.7875;
1211
1212   Float_t alpha;
1213   Float_t astep;
1214
1215   Float_t phi1,phi2,phi3,theta1,theta2,theta3; // rotation angles
1216
1217   // inner part of the inner sector - 2 x 20 holes
1218   
1219   astep = 20.00096874/19.;
1220
1221   alpha = 10.00048437-astep;
1222
1223   Float_t x1,x2;
1224
1225     x1 = 13.31175725;
1226     x1 -= 0.996357832; 
1227
1228     x2 = 15.06180253;
1229     x2 -= 1.163028812;
1230
1231   Int_t ncon;
1232
1233   for(ncon=0;ncon<20;ncon++){
1234
1235     phi1 = 0.;
1236     theta1 = 90.+alpha;
1237     phi2=90.;
1238     theta2 = 90.;
1239     phi3 = (alpha>0) ? 0. : 180.;
1240     theta3 = TMath::Abs(alpha);
1241
1242     AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
1243
1244  
1245
1246     gMC->Gspos("TPSC",ncon+1,"TIRC",x1,0.3,-12.7875,idrotm[nRotMat],"ONLY");
1247     gMC->Gspos("TPSC",ncon+21,"TIRC",x2,0.3,-2.8625,idrotm[nRotMat],"ONLY");
1248
1249
1250     x1 -= 1.296357833;
1251     x2 -= 1.463028812;
1252
1253     alpha -= astep;   
1254     nRotMat++; 
1255
1256   }
1257
1258   // outer part of the inner sector - 2 x 25 holes
1259
1260    astep = 20.00096874/24.; 
1261    alpha = 10.00048437-astep;
1262
1263    x1 = 16.81184781;
1264    x1 -= 1.016295986;
1265
1266    x2 = 18.5618931;
1267    x2 -= 1.150914854;
1268
1269   for(ncon=0;ncon<25;ncon++){
1270
1271     phi1 = 0.;
1272     theta1 = 90.+alpha;
1273     phi2=90.;
1274     theta2 = 90.;
1275     phi3 = (alpha>0) ? 0. : 180.;
1276     theta3 = TMath::Abs(alpha);
1277
1278     AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
1279
1280  
1281
1282     gMC->Gspos("TPSC",ncon+41,"TIRC",x1,0.3,7.0625,idrotm[nRotMat],"ONLY");
1283     gMC->Gspos("TPSC",ncon+66,"TIRC",x2,0.3,16.9875,idrotm[nRotMat],"ONLY");
1284
1285
1286     x1 -= 1.316295986;
1287     x2 -= 1.450914854;
1288
1289     alpha -= astep;   
1290     nRotMat++; 
1291
1292   }  
1293
1294   //--------------------------------------------------------------------------
1295   //  TPC Outer Readout Chambers
1296   //  this is NOT a final design
1297   //--------------------------------------------------------------------------
1298
1299   dm[0]= 23.3875;
1300   dm[1]= 43.524;
1301   dm[2]= 1.5; //thickness
1302   dm[3]= 57.1;
1303
1304   gMC->Gsvolu("TORC","TRD1",idtmed[4],dm,4);
1305
1306   //------------------------------------------------
1307   // Tpc Outer readout chamber Pad Plane
1308   //------------------------------------------------
1309
1310   dm[2]= 0.5;
1311
1312   gMC->Gsvolu("TOPP","TRD1",idtmed[12],dm,4);
1313
1314   dm[0] -= 1.218511934;
1315   dm[1] -= 1.218511934;
1316   dm[2] = 0.35;
1317
1318   gMC->Gsvolu("TOC3","TRD1",idtmed[1],dm,4);
1319
1320   gMC->Gspos("TOC3",1,"TOPP",0.,0.15,0.,0,"ONLY");
1321
1322   gMC->Gspos("TOPP",1,"TORC",0.,1.0,0.,0,"ONLY");
1323
1324   // empty space
1325
1326
1327   dm[0]= 21.035;
1328   dm[1]= 38.7205;
1329   dm[2]= 0.7; 
1330   dm[3]= 50.15;
1331
1332   gMC->Gsposp("TRCE",10,"TORC",0.,-0.8,-2.15,0,"ONLY",dm,4);  
1333
1334   dm[0]= 22.2935;
1335   dm[1]= 40.5085;
1336   dm[2]= 2.25;
1337   dm[3]= 51.65;
1338
1339   gMC->Gsvolu("TOC1","TRD1",idtmed[4],dm,4);
1340
1341   dm[0]= 21.35;
1342   dm[1]= 38.7205;
1343   dm[2]= 2.25;
1344   dm[3]= 50.15;
1345
1346   gMC->Gsposp("TRCE",11,"TOC1",0.,0.,0.,0,"ONLY",dm,4); 
1347
1348
1349
1350   //-----------------------------------------------
1351   // Tpc Services Support Wheel
1352   //-----------------------------------------------
1353
1354   dm[0]=0.;
1355   dm[1]=360.;
1356   dm[2]=18.;
1357   dm[3]=2.;
1358
1359   dm[4]= -5.;
1360   dm[5]= 77.017;
1361   dm[6]= 255.267;
1362
1363   dm[7]= 5.;
1364   dm[8]= dm[5];
1365   dm[9]= dm[6];
1366
1367   gMC->Gsvolu("TSSW","PGON",idtmed[4],dm,10);
1368
1369   // Tpc Services Wheel Cover
1370
1371   dm[4]= -0.5;
1372   dm[7]= 0.5;
1373
1374   gMC->Gsvolu("TSWC","PGON",idtmed[4],dm,10);
1375
1376   // Tpc Service wheel Cover Empty space
1377    
1378   dm[0]= 10.99;
1379   dm[1]= 39.599;
1380   dm[2]= .5;
1381   dm[3]= 81.125;
1382
1383   gMC->Gsvolu("TSCE","TRD1",idtmed[0],dm,4);
1384
1385   // Tpc services Wheel Empty Spaces
1386
1387   dm[0]= 13.18017507;
1388   dm[1]= 44.61045938;
1389   dm[2]= 4.;
1390   dm[3]= 89.125;
1391
1392   gMC->Gsvolu("TWES","TRD1",idtmed[0],dm,4);
1393
1394   // Tpc Services Wheel Bars
1395
1396   gMC->Gsvolu("TSWB","TRD1",idtmed[4],dm,0);
1397
1398   // bars-> TWES
1399
1400   dm[2]= 4.;
1401   dm[3]= .4;
1402
1403   dm[0]= 13.8149522;
1404   dm[1]= 13.95601379;
1405   
1406   gMC->Gsposp("TSWB",1,"TWES",0.,0.,-85.125,0,"ONLY",dm,4);
1407
1408   dm[0]= 43.83462067; 
1409   dm[1]= 43.97568225;
1410
1411   gMC->Gsposp("TSWB",2,"TWES",0.,0.,85.125,0,"ONLY",dm,4);
1412
1413   // TPc ELectronics - right now 30% X0 Si
1414
1415   dm[0]= 14.03813696;
1416   dm[1]= 43.3524075;
1417   dm[2]= 1.404;
1418   dm[3]= 83.125;
1419
1420   gMC->Gsvolu("TPEL","TRD1",idtmed[11],dm,4);
1421   gMC->Gspos("TPEL",1,"TWES",0.,0.,0.,0,"ONLY");
1422
1423   //--------------------------------------------------------------------------
1424   //  End caps
1425   //--------------------------------------------------------------------------
1426
1427   // TPc Main Wheel - Al
1428
1429   dm[0]= 75.3;
1430   dm[1]= 264.8;
1431   dm[2]= 3.0;
1432
1433   gMC->Gsvolu("TPMW","TUBE",idtmed[4],dm,3);
1434
1435   // TPc Extra Wheel (to avoid overlapping) - Al
1436
1437   dm[0]= 264.8;
1438   dm[1]= 277.0;
1439   dm[2]= 1.95;
1440
1441   gMC->Gsvolu("TPEW","TUBE",idtmed[4],dm,3);
1442
1443   //--------------------------------------------------------------------------
1444   //  Tpc Empty Space for the Readout chambers
1445   //--------------------------------------------------------------------------  
1446
1447   Float_t rLow= 86.2;
1448   Float_t rUp= 243.5;
1449   Float_t dR = 0.5*(rUp-rLow);
1450
1451   space= 1.4/cosAlpha; // wheel ribs are 2.8 cm wide
1452
1453   dm[0]= rLow*tanAlpha-space;
1454   dm[1]= rUp*tanAlpha-space;
1455   dm[2]= 3.0;
1456   dm[3]= dR;
1457
1458   gMC->Gsvolu("TESR","TRD1",idtmed[0],dm,4);
1459
1460   // TIC1->TESR
1461
1462
1463   gMC->Gspos("TIC1",1,"TESR",0.,0.75,-dR+23.97,0,"ONLY");
1464
1465
1466   // TOC1->TESR
1467
1468   gMC->Gspos("TOC1",1,"TESR",0.,0.75,dR-55.02,0,"ONLY");
1469
1470   // Tpc Empty Space Bars - Al (daughters of TESR)
1471
1472   Float_t zBar;
1473
1474   gMC->Gsvolu("TESB","TRD1",idtmed[4],dm,0);
1475
1476   // lower bar
1477
1478   dm[0]= rLow*tanAlpha-space;
1479   dm[1]= 88.7*tanAlpha-space;
1480   dm[2]= 0.95;
1481   dm[3]= 1.275;
1482
1483   zBar = -dR+dm[3];
1484
1485   gMC->Gsposp("TESB",1,"TESR",0.,2.05,zBar,0,"ONLY",dm,4);
1486
1487   // middle bar
1488
1489   dm[0]= 131.65*tanAlpha-space;
1490   dm[1]= 136.5*tanAlpha-space;
1491   dm[3]= 2.425;
1492
1493   zBar = -dR +131.65+dm[3]-rLow;
1494
1495   gMC->Gsposp("TESB",2,"TESR",0.,2.05,zBar,0,"ONLY",dm,4);
1496
1497   // upper bar
1498
1499   dm[0]= 240.4*tanAlpha-space;
1500   dm[1]= rUp*tanAlpha-space;
1501   dm[3]= 1.55;
1502
1503   zBar = dR-dm[3];
1504
1505   gMC->Gsposp("TESB",3,"TESR",0.,2.05,zBar,0,"ONLY",dm,4);
1506
1507   //------------------------------------------------------
1508   //  TPc Lower "S" Sectors 
1509   //------------------------------------------------------
1510
1511
1512   Float_t inSecLowEdge = fTPCParam->GetInnerRadiusLow();
1513   Float_t inSecUpEdge =  fTPCParam->GetInnerRadiusUp();
1514
1515   dm[0] = inSecLowEdge*TMath::Tan(0.5*innerOpenAngle)-0.01;
1516   dm[1] = inSecUpEdge*TMath::Tan(0.5*innerOpenAngle)-0.01;
1517   dm[2] = 0.5*(250. - 0.3);
1518   dm[3] = 0.5*(inSecUpEdge-inSecLowEdge);  
1519
1520   gMC->Gsvolu("TPLS", "TRD1", idtmed[2], dm, 4); // sensitive 
1521
1522   //----------------------------------------------------------
1523   //  TPc Upper Sectors
1524   //----------------------------------------------------------
1525
1526   Float_t ouSecLowEdge = fTPCParam->GetOuterRadiusLow();
1527   Float_t ouSecUpEdge = fTPCParam->GetOuterRadiusUp();
1528
1529   dm[0] = ouSecLowEdge*TMath::Tan(0.5*outerOpenAngle)-0.01;  
1530   dm[1] = ouSecUpEdge*TMath::Tan(0.5*outerOpenAngle)-0.01;  
1531   dm[2] = 0.5*(250. - 0.3);
1532   dm[3] = 0.5*(ouSecUpEdge-ouSecLowEdge);
1533
1534   gMC->Gsvolu("TPUS", "TRD1", idtmed[2], dm, 4); // sensitive
1535
1536
1537
1538
1539     gMC->Gsvolu("TPSS","TRD1",idtmed[2],dm,0); // sensitive
1540
1541     Int_t nofStrips,nstr;
1542     Float_t r1,r2,zs;
1543     Float_t stripThick = 0.01; // 100 microns
1544     Float_t deadSpace;
1545
1546     // inner sector
1547
1548
1549     // if all lower sectors selected define only 1 strip
1550
1551     nofStrips=((fSecAL <0)||(fSecAL>=0 && fSens<0)) ? 1 : fTPCParam->GetNRowLow(); 
1552     deadSpace = fTPCParam->GetInnerWireMount();
1553
1554     dm[2] = 0.5*(250. - 0.3);
1555     dm[3] = 0.5 * stripThick;  
1556
1557
1558     for(nstr=0;nstr<nofStrips;nstr++){
1559
1560       r1 = fTPCParam->GetPadRowRadiiLow(nstr);
1561       r2 = r1 + stripThick;     
1562       dm[0] = r1 * TMath::Tan(0.5*innerOpenAngle) - deadSpace;
1563       dm[1] = r2 * TMath::Tan(0.5*innerOpenAngle) - deadSpace;
1564       zs = -inSecLowEdge -0.5*(inSecUpEdge-inSecLowEdge);
1565       zs += r1;
1566       zs += dm[3];
1567     
1568       gMC->Gsposp("TPSS", nstr+1, "TPLS", 0., 0., zs, 0, "ONLY", dm, 4);
1569
1570
1571     }
1572
1573     // strips only if several upper sectors selected end fSens > 0
1574
1575     if(fSecAU >=0 && fSens >0){
1576
1577     Int_t nsSave = nofStrips;
1578
1579     // outer sector
1580
1581     nofStrips = fTPCParam->GetNRowUp();
1582     deadSpace = fTPCParam->GetOuterWireMount();
1583
1584     dm[2] = 0.5*(250. - 0.3);
1585     dm[3] = 0.5 * stripThick;
1586
1587   
1588     for(nstr=0;nstr<nofStrips;nstr++){
1589     
1590       r1 = fTPCParam->GetPadRowRadiiUp(nstr); 
1591       r2 = r1 + stripThick;
1592       dm[0] = r1 * TMath::Tan(0.5*outerOpenAngle) - deadSpace;
1593       dm[1] = r2 * TMath::Tan(0.5*outerOpenAngle) - deadSpace;
1594       zs = -ouSecLowEdge -0.5*(ouSecUpEdge-ouSecLowEdge);
1595       zs += r1;
1596       zs += dm[3];
1597
1598       gMC->Gsposp("TPSS", nstr+1+nsSave, "TPUS", 0., 0., zs, 0, "ONLY", dm, 4);
1599
1600      }    
1601     }
1602
1603   //-------------------------------------------------------
1604   //  positioning of the empty spaces into the main wheel
1605   //  and readout chambers and sectors into the drift gas
1606   //-------------------------------------------------------
1607
1608   Float_t rCenter,xc,yc;
1609   Float_t rInner,rOuter; // center of the inner and outer chamber
1610
1611   rCenter = rLow+dR;
1612
1613   rInner = 108.07;
1614   rOuter = 190.68;
1615
1616   for(Int_t ns=0; ns<nInnerSector;ns++){
1617
1618     phi1 = ns * innerOpenAngle + innerAngleShift;
1619     phi1 *= kRaddeg; // in degrees
1620
1621     phi1 = (Float_t)TMath::Nint(phi1) + 270.;
1622
1623     if (phi1 > 360.) phi1 -= 360.;
1624
1625     theta1 = 90.;
1626     phi2   = 90.;
1627     theta2 = 180.;
1628     phi3   = ns * innerOpenAngle + innerAngleShift;
1629     phi3 *= kRaddeg; // in degrees
1630
1631     phi3 = (Float_t)TMath::Nint(phi3);
1632       
1633     if(phi3 > 360.) phi3 -= 360.;
1634
1635     theta3 = 90.;
1636
1637     // "holes"->End plate
1638
1639     xc = rCenter*TMath::Cos(phi3*kDegrad);
1640     yc = rCenter*TMath::Sin(phi3*kDegrad);
1641
1642     AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
1643
1644     gMC->Gspos("TESR",ns+1,"TPMW",xc,yc,0.,idrotm[nRotMat],"ONLY");
1645
1646     // TSCE->TSWC (services wheel volumes)
1647
1648     xc = 166.142*TMath::Cos(phi3*kDegrad);
1649     yc = 166.142*TMath::Sin(phi3*kDegrad);
1650
1651     gMC->Gspos("TSCE",ns+1,"TSWC",xc,yc,0.,idrotm[nRotMat],"ONLY");
1652     gMC->Gspos("TWES",ns+1,"TSSW",xc,yc,0.,idrotm[nRotMat],"ONLY");
1653
1654     // readout chambers->TDGN (drift gas)
1655
1656     xc = rInner*TMath::Cos(phi3*kDegrad);
1657     yc = rInner*TMath::Sin(phi3*kDegrad);
1658
1659     gMC->Gspos("TIRC",ns+1,"TDGN",xc,yc,252.,idrotm[nRotMat],"ONLY");
1660
1661     // here lower sectors 
1662
1663     if(fSecAL <0){
1664
1665       // all lower sectors are positioned
1666
1667       gMC->Gspos("TPLS",ns+1,"TDGN",xc,yc,125.15,idrotm[nRotMat],"ONLY");
1668       gMC->
1669         Gspos("TPLS",ns+nInnerSector+1,"TDGN",xc,yc,-125.15,idrotm[nRotMat],"ONLY");
1670     }
1671     else{
1672
1673       // only selected sectors are positioned (up to 6 sectors)
1674
1675       for(Int_t sel=0;sel<6;sel++){
1676
1677         if(fSecLows[sel] == ns){
1678           gMC->Gspos("TPLS",ns+1,"TDGN",xc,yc,125.15,idrotm[nRotMat],"ONLY");
1679         }
1680         else if(fSecLows[sel] == ns+nInnerSector){
1681          gMC->
1682           Gspos("TPLS",ns+nInnerSector+1,"TDGN",xc,yc,-125.15,idrotm[nRotMat],"ONLY");
1683         }
1684       }
1685     } // lower sectors finished
1686      
1687     xc = rOuter*TMath::Cos(phi3*kDegrad);
1688     yc = rOuter*TMath::Sin(phi3*kDegrad);
1689
1690     gMC->Gspos("TORC",ns+1,"TDGN",xc,yc,252.1,idrotm[nRotMat],"ONLY");
1691
1692     // here upper sectors 
1693
1694     if(fSecAU <0){
1695
1696       // all upper sectors
1697
1698       gMC->Gspos("TPUS",ns+1,"TDGN",xc,yc,125.15,idrotm[nRotMat],"ONLY");
1699       gMC->
1700         Gspos("TPUS",ns+nOuterSector+1,"TDGN",xc,yc,-125.15,idrotm[nRotMat],"ONLY");
1701     }
1702     else{
1703
1704       // only selected sectors (up to 12)
1705
1706       for(Int_t sel=0;sel<12;sel++){
1707         if(fSecUps[sel] == ns+2*nInnerSector){
1708           gMC->Gspos("TPUS",ns+1,"TDGN",xc,yc,125.15,idrotm[nRotMat],"ONLY");
1709         }         
1710         else if(fSecUps[sel] == ns+2*nInnerSector+nOuterSector){
1711          gMC->
1712           Gspos("TPUS",ns+nOuterSector+1,"TDGN",xc,yc,-125.15,idrotm[nRotMat],"ONLY"); 
1713         }
1714       }
1715     } // upper sectors finished
1716
1717     nRotMat++;
1718
1719     theta2 = 0.; // reflection, needed for readout chambers!
1720
1721     AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
1722
1723     xc = rInner*TMath::Cos(phi3*kDegrad);
1724     yc = rInner*TMath::Sin(phi3*kDegrad);
1725
1726     gMC->Gspos("TIRC",ns+nInnerSector+1,"TDGN",xc,yc,-252.,idrotm[nRotMat],"ONLY");
1727
1728     xc = rOuter*TMath::Cos(phi3*kDegrad);
1729     yc = rOuter*TMath::Sin(phi3*kDegrad);
1730
1731     gMC->Gspos("TORC",ns+nOuterSector+1,"TDGN",xc,yc,-252.1,idrotm[nRotMat],"ONLY");
1732
1733     nRotMat++;
1734
1735
1736   } 
1737
1738   // reflection matrix
1739
1740   theta1 = 90.;
1741   phi1   = 0.;
1742   theta2 = 90.;
1743   phi2   = 270.;
1744   theta3 = 180.;
1745   phi3   = 0.;
1746
1747   AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
1748
1749
1750   // TPMW->TPC
1751
1752   gMC->Gspos("TPMW",1,"TPC ",0.,0.,256.6,0,"ONLY");
1753   gMC->Gspos("TPMW",2,"TPC ",0.,0.,-256.6,idrotm[nRotMat],"ONLY");
1754   gMC->Gspos("TPEW",1,"TPC ",0.,0.,257.65,0,"ONLY");
1755   gMC->Gspos("TPEW",2,"TPC ",0.,0.,-257.65,0,"ONLY");
1756
1757
1758
1759   //-------------------------------------------------------
1760   // Tpc High Voltage Membrane - NOMEX honeycomb
1761   //-------------------------------------------------------
1762
1763   dm[0]=0.,
1764   dm[1]=360.;
1765   dm[2]=18.;
1766   dm[3]=2.;
1767
1768   //
1769
1770   dm[4]= -0.3;
1771   dm[5]= 81.156;
1772   dm[6]= 253.386;
1773
1774   //
1775
1776   dm[7]= 0.3;
1777   dm[8]= dm[5];
1778   dm[9]= dm[6];
1779
1780   gMC->Gsvolu("THVM","PGON",idtmed[6],dm,10);
1781
1782   gMC->Gspos("THVM",1,"TDGN",0.,0.,0.,0,"ONLY");
1783
1784   //----------------------------------------------------------
1785   // TPc Support Rods - MAKROLON
1786   //----------------------------------------------------------
1787
1788   dm[0]= 0.9;
1789   dm[1]= 1.2;
1790   dm[2]= 126.65;
1791
1792   gMC->Gsvolu("TPSR","TUBE",idtmed[7],dm,3);
1793
1794   for(Int_t nrod=1;nrod<18;nrod++){
1795     Float_t angle=innerOpenAngle*(Float_t)nrod;
1796
1797     xc=82.4*TMath::Cos(angle);
1798     yc=82.4*TMath::Sin(angle);
1799
1800     gMC->Gspos("TPSR",nrod,"TDGN",xc,yc,126.95,0,"ONLY");
1801     gMC->Gspos("TPSR",nrod+17,"TDGN",xc,yc,-126.95,0,"ONLY");
1802
1803     xc=254.2*TMath::Cos(angle);
1804     yc=254.2*TMath::Sin(angle);
1805
1806     gMC->Gspos("TPSR",nrod+34,"TDGN",xc,yc,126.95,0,"ONLY");
1807     gMC->Gspos("TPSR",nrod+51,"TDGN",xc,yc,-126.95,0,"ONLY");    
1808
1809   }
1810
1811   //----------------------------------------------------------
1812   // Tpc High Voltage rod - MAKROLON + Copper cable
1813   //----------------------------------------------------------
1814
1815   // rod with cable (Left)
1816
1817   dm[0]=0.;
1818   dm[1]=2.25;
1819   dm[2]=126.65;
1820
1821   gMC->Gsvolu("THVL","TUBE",idtmed[7],dm,3);
1822
1823   // HV cable
1824  
1825   dm[0]=0.;
1826   dm[1]=0.3;
1827   dm[2]=126.65;
1828
1829   gMC->Gsvolu("THVC","TUBE",idtmed[10],dm,3);
1830
1831   // empty space
1832
1833   dm[0]=0.3;
1834   dm[1]=1.;
1835   dm[2]=126.65;
1836
1837   gMC->Gsvolu("THVE","TUBE",idtmed[1],dm,3);
1838
1839   gMC->Gspos("THVC",1,"THVL",0.,0.,0.,0,"ONLY");
1840   gMC->Gspos("THVE",1,"THVL",0.,0.,0.,0,"ONLY");
1841
1842   // rod without cable
1843
1844   dm[0]=1.8;
1845   dm[1]=2.25;
1846   dm[2]=126.65;
1847
1848   gMC->Gsvolu("THVR","TUBE",idtmed[7],dm,3);
1849
1850   
1851   
1852   gMC->Gspos("THVL",1,"TDGN",82.4,0.,-126.95,0,"ONLY");
1853   gMC->Gspos("THVL",2,"TDGN",254.2,0.,-126.95,0,"ONLY");
1854
1855   gMC->Gspos("THVR",1,"TDGN",82.4,0.,126.95,0,"ONLY");
1856   gMC->Gspos("THVR",2,"TDGN",254.2,0.,126.95,0,"ONLY");  
1857   
1858
1859
1860   gMC->Gspos("TDGN",1,"TPC ",0.,0.,0.,0,"ONLY"); 
1861
1862   // services wheel cover -> wheel
1863
1864
1865   gMC->Gspos("TSWC",1,"TSSW",0.,0.,4.5,0,"ONLY");
1866   gMC->Gspos("TSWC",2,"TSSW",0.,0.,-4.5,0,"ONLY");
1867
1868
1869   // put the wheel into the TPC
1870
1871   gMC->Gspos("TSSW",1,"TPC ",0.,0.,278.7,0,"ONLY");
1872   gMC->Gspos("TSSW",2,"TPC ",0.,0.,-278.7,0,"ONLY");
1873
1874   gMC->Gsord("TPMW",6);
1875   if(fSecAL >=0)  gMC->Gsord("TPLS",3);
1876   if(fSecAU >=0 && fSens >0)  gMC->Gsord("TPUS",3);
1877   gMC->Gsord("TDGN",6);
1878   gMC->Gsord("TSSW",6);
1879   gMC->Gsord("TSWC",6);
1880
1881   // put the TPC into ALIC (main mother volume)
1882
1883   gMC->Gspos("TPC ", 1, "ALIC", 0, 0, 0, 0, "ONLY");  
1884
1885 } // end of function
1886  
1887 //_____________________________________________________________________________
1888 void AliTPCv2::DrawDetector()
1889 {
1890   //
1891   // Draw a shaded view of the Time Projection Chamber version 1
1892   //
1893
1894   // Set everything unseen
1895   gMC->Gsatt("*", "seen", -1);
1896   // 
1897   // Set ALIC mother transparent
1898   gMC->Gsatt("ALIC","SEEN",0);
1899   //
1900   // Set the volumes visible
1901   //
1902
1903   gMC->Gsatt("TPC ","SEEN",0);
1904   gMC->Gsatt("TOIN","SEEN",1);
1905   gMC->Gsatt("TOIN","COLO",7);
1906   gMC->Gsatt("TPCR","SEEN",0);
1907   gMC->Gsatt("TOCV","SEEN",1);
1908   gMC->Gsatt("TOCV","COLO",4);
1909   gMC->Gsatt("TSA1","SEEN",0);
1910   gMC->Gsatt("TSA2","SEEN",0);
1911   gMC->Gsatt("TSA3","SEEN",0);
1912   gMC->Gsatt("TSA4","SEEN",0);
1913   gMC->Gsatt("TOFC","SEEN",1);
1914   gMC->Gsatt("TOFC","COLO",4);
1915   gMC->Gsatt("TSA5","SEEN",0);
1916   gMC->Gsatt("TSA6","SEEN",0);
1917   gMC->Gsatt("TSA7","SEEN",0);
1918   gMC->Gsatt("TSA8","SEEN",0);
1919   gMC->Gsatt("TIIN","COLO",7);
1920   gMC->Gsatt("TIIN","SEEN",1);
1921   gMC->Gsatt("TICL","SEEN",0);
1922   gMC->Gsatt("TSA9","SEEN",0);
1923   gMC->Gsatt("TS10","SEEN",0);
1924   gMC->Gsatt("TS11","SEEN",0);
1925   gMC->Gsatt("TS12","SEEN",0);
1926   gMC->Gsatt("TICR","SEEN",0); 
1927   gMC->Gsatt("TS13","SEEN",0);
1928   gMC->Gsatt("TS14","SEEN",0);
1929   gMC->Gsatt("TS15","SEEN",0);
1930   gMC->Gsatt("TS16","SEEN",0);
1931   gMC->Gsatt("TIFC","SEEN",1);
1932   gMC->Gsatt("TIFC","COLO",4); 
1933   gMC->Gsatt("TS17","SEEN",0);
1934   gMC->Gsatt("TS18","SEEN",0);
1935   gMC->Gsatt("TS19","SEEN",0);
1936   gMC->Gsatt("TS20","SEEN",0);
1937   gMC->Gsatt("TS21","SEEN",0);
1938   gMC->Gsatt("TS22","SEEN",0);
1939   gMC->Gsatt("TS23","SEEN",0);
1940   gMC->Gsatt("TS24","SEEN",0);
1941   gMC->Gsatt("TDGN","SEEN",0);
1942   gMC->Gsatt("TIRC","SEEN",0);
1943   gMC->Gsatt("TIC1","SEEN",1);
1944   gMC->Gsatt("TIPP","SEEN",0);
1945   gMC->Gsatt("TIC3","SEEN",0);
1946   gMC->Gsatt("TRCE","SEEN",0);
1947   gMC->Gsatt("TPSC","SEEN",0);
1948   gMC->Gsatt("TPCC","SEEN",0);
1949   gMC->Gsatt("TORC","SEEN",0);
1950   gMC->Gsatt("TOPP","SEEN",0);
1951   gMC->Gsatt("TOC3","SEEN",0);
1952   gMC->Gsatt("TOC1","SEEN",1);
1953   gMC->Gsatt("TSSW","SEEN",1);
1954   gMC->Gsatt("TSWC","SEEN",1);
1955   gMC->Gsatt("TSCE","SEEN",1); 
1956   gMC->Gsatt("TSSW","COLO",3);
1957   gMC->Gsatt("TSWC","COLO",3);
1958   gMC->Gsatt("TSCE","COLO",6);
1959   gMC->Gsatt("TWES","SEEN",0);
1960   gMC->Gsatt("TSWB","SEEN",0);
1961   gMC->Gsatt("TPEL","SEEN",0);
1962   gMC->Gsatt("TPMW","SEEN",1);
1963   gMC->Gsatt("TPEW","SEEN",1);
1964   gMC->Gsatt("TESR","SEEN",1);
1965   gMC->Gsatt("TPMW","COLO",12);
1966   gMC->Gsatt("TPEW","COLO",12);
1967   gMC->Gsatt("TWES","COLO",5);
1968   gMC->Gsatt("TIC1","COLO",5);
1969   gMC->Gsatt("TOC1","COLO",5);  
1970   gMC->Gsatt("TESB","SEEN",0);
1971   gMC->Gsatt("TPLS","SEEN",0);
1972   gMC->Gsatt("TPUS","SEEN",0);
1973   gMC->Gsatt("TPSS","SEEN",0);
1974   gMC->Gsatt("THVM","SEEN",1);
1975   gMC->Gsatt("THVM","COLO",11);
1976   gMC->Gsatt("TPSR","SEEN",0);
1977   gMC->Gsatt("THVL","SEEN",0);
1978   gMC->Gsatt("THVC","SEEN",0);
1979   gMC->Gsatt("THVE","SEEN",0);
1980   gMC->Gsatt("THVR","SEEN",0);
1981
1982   //
1983   gMC->Gdopt("hide", "on");
1984   gMC->Gdopt("shad", "on");
1985   gMC->Gsatt("*", "fill", 7);
1986   gMC->SetClipBox(".");
1987   gMC->SetClipBox("TPMW",-300,300,-300,300,254.,270.);
1988   gMC->SetClipBox("TESR",-300,300,-300,300,254.,270.);
1989   gMC->SetClipBox("TSSW",-300,300,-300,300,283.,284.);
1990   gMC->SetClipBox("TSWC",-300,300,-300,300,283.,284.);
1991   gMC->SetClipBox("*", 0, 300, -300, 300, -290, 290);
1992   gMC->DefaultRange();
1993   gMC->Gdraw("alic", 40, 30, 0, 12, 9.5, .025, .025);
1994   gMC->Gdhead(1111, "Time Projection Chamber");
1995   gMC->Gdman(18, 4, "MAN");
1996   gMC->Gdopt("hide","off");
1997 }
1998
1999 //_____________________________________________________________________________
2000 void AliTPCv2::CreateMaterials()
2001 {
2002   //
2003   // Define materials for version 2 of the Time Projection Chamber
2004   //
2005  
2006   AliTPC::CreateMaterials();
2007 }
2008
2009 //_____________________________________________________________________________
2010 void AliTPCv2::Init()
2011 {
2012   //
2013   // Initialises version 2 of the TPC after that it has been built
2014   //
2015
2016   Int_t *idtmed = fIdtmed->GetArray();
2017   
2018   AliTPC::Init();
2019
2020
2021   
2022   fIdSens=gMC->VolId("TPSS");  
2023
2024   fIdLSec=gMC->VolId("TPLS"); // lower sector 
2025   fIdUSec=gMC->VolId("TPUS"); // upper sector
2026
2027   gMC->SetMaxNStep(30000); // max. number of steps increased
2028
2029   gMC->Gstpar(idtmed[2],"LOSS",5); // specific energy loss
2030
2031   printf("*** TPC version 2 initialized ***\n");
2032   printf("Maximum number of steps = %d\n",gMC->GetMaxNStep());
2033
2034   //
2035   
2036 }
2037
2038 //_____________________________________________________________________________
2039 void AliTPCv2::StepManager()
2040 {
2041   //
2042   // Called for every step in the Time Projection Chamber
2043   //
2044
2045   //
2046   // parameters used for the energy loss calculations
2047   //
2048   const Float_t kprim = 14.35; // number of primary collisions per 1 cm
2049   const Float_t kpoti = 20.77e-9; // first ionization potential for Ne/CO2
2050   const Float_t kwIon = 35.97e-9; // energy for the ion-electron pair creation 
2051  
2052  
2053   const Float_t kbig = 1.e10;
2054
2055   Int_t id,copy;
2056   Float_t hits[4];
2057   Int_t vol[2];  
2058   TClonesArray &lhits = *fHits;
2059   TLorentzVector p;
2060   
2061   vol[1]=0; // preset row number to 0
2062
2063   //
2064
2065   gMC->SetMaxStep(kbig);
2066   
2067   if(!gMC->IsTrackAlive()) return; // particle has disappeared
2068   
2069   Float_t charge = gMC->TrackCharge();
2070   
2071   if(TMath::Abs(charge)<=0.) return; // take only charged particles
2072   
2073   // check the sensitive volume
2074
2075   id = gMC->CurrentVolID(copy); // current volume Id
2076
2077   if(id == fIdLSec){
2078     vol[0] = copy-1; // lower sector number
2079   }
2080   else if(id == fIdUSec){
2081     vol[0] = copy+fTPCParam->GetNInnerSector()-1; // upper sector number
2082   }
2083   else if(id == fIdSens && gMC->IsTrackEntering()){
2084  
2085     // track is entering the sensitive strip
2086     
2087     vol[1]= copy-1; // row number (absolute)
2088    
2089     // sector type
2090  
2091     id = gMC->CurrentVolOffID(1,copy);
2092
2093     if(id == fIdLSec){
2094
2095       // lower sector
2096      
2097       vol[0] = copy-1; // sector number
2098
2099     }
2100     else {
2101    
2102       // upper sector
2103
2104       vol[0] = copy-1+fTPCParam->GetNInnerSector(); // sector number
2105       vol[1] -= fTPCParam->GetNRowLow(); // row number  
2106
2107     } 
2108
2109     if(vol[1] == 0){
2110   
2111       // because Jouri wants to have this
2112
2113       gMC->TrackMomentum(p);
2114       hits[0]=p[0];
2115       hits[1]=p[1];
2116       hits[2]=p[2];
2117       hits[3]=0.; // this hit has no energy loss
2118       new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
2119
2120     }
2121
2122      gMC->TrackPosition(p);
2123      hits[0]=p[0];
2124      hits[1]=p[1];
2125      hits[2]=p[2];
2126      hits[3]=0.; // this hit has no energy loss
2127      new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
2128
2129     
2130   }
2131   else return;
2132     
2133   //-----------------------------------------------------------------
2134   //  charged particle is in the sensitive volume
2135   //-----------------------------------------------------------------
2136   
2137   if(gMC->TrackStep() > 0) {
2138     
2139     Int_t nel = (Int_t)(((gMC->Edep())-kpoti)/kwIon) + 1;
2140     nel=TMath::Min(nel,300); // 300 electrons corresponds to 10 keV
2141     
2142     gMC->TrackPosition(p);
2143     hits[0]=p[0];
2144     hits[1]=p[1];
2145     hits[2]=p[2];
2146     hits[3]=(Float_t)nel;
2147     
2148     // Add this hit
2149     
2150     new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
2151     
2152   } 
2153   
2154   // Stemax calculation for the next step
2155   
2156   Float_t pp;
2157   TLorentzVector mom;
2158   gMC->TrackMomentum(mom);
2159   Float_t ptot=mom.Rho();
2160   Float_t betaGamma = ptot/gMC->TrackMass();
2161   
2162   Int_t pid=gMC->TrackPid();
2163   if((pid==kElectron || pid==kPositron) && ptot > 0.002)
2164     { 
2165       pp = kprim*1.58; // electrons above 20 MeV/c are on the plateau!
2166     }
2167   else
2168     {
2169       pp=kprim*BetheBloch(betaGamma);    
2170       if(TMath::Abs(charge) > 1.) pp *= (charge*charge);
2171     }
2172   
2173   Float_t random[1];
2174   gMC->Rndm(random,1); // good, old GRNDM from Geant3
2175   
2176   Double_t rnd = (Double_t)random[0];
2177   
2178   gMC->SetMaxStep(-TMath::Log(rnd)/pp);
2179   
2180 }
2181
2182 //_____________________________________________________________________________
2183 Float_t AliTPCv2::BetheBloch(Float_t bg)
2184 {
2185   //
2186   // Bethe-Bloch energy loss formula
2187   //
2188   const Double_t kp1=0.76176e-1;
2189   const Double_t kp2=10.632;
2190   const Double_t kp3=0.13279e-4;
2191   const Double_t kp4=1.8631;
2192   const Double_t kp5=1.9479;
2193
2194   Double_t dbg = (Double_t) bg;
2195
2196   Double_t beta = dbg/TMath::Sqrt(1.+dbg*dbg);
2197
2198   Double_t aa = TMath::Power(beta,kp4);
2199   Double_t bb = TMath::Power(1./dbg,kp5);
2200
2201   bb=TMath::Log(kp3+bb);
2202   
2203   return ((Float_t)((kp2-aa-bb)*kp1/aa));
2204 }
2205
2206