1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
18 Revision 1.47 2003/03/04 15:16:54 kowal2
19 Geometry corrected for an overlap
21 Revision 1.46 2003/02/11 16:54:07 hristov
22 Updated AliTrackReference class (S.Radomski)
24 Revision 1.45 2003/01/14 10:50:20 alibrary
25 Cleanup of STEER coding conventions
27 Revision 1.44 2002/11/21 22:43:32 alibrary
28 Removing AliMC and AliMCProcess
30 Revision 1.43 2002/10/14 14:57:43 hristov
31 Merging the VirtualMC branch to the main development branch (HEAD)
33 Revision 1.40.6.2 2002/07/24 10:09:01 alibrary
36 Revision 1.42 2002/06/12 14:56:56 kowal2
37 Added track length to the reference hits
39 Revision 1.41 2002/05/27 14:33:15 hristov
40 The new class AliTrackReference used (M.Ivanov)
42 Revision 1.40 2002/01/21 17:12:00 kowal2
43 New track hits structure using root containers
45 Revision 1.39 2001/05/16 14:57:25 alibrary
46 New files for folders and Stack
48 Revision 1.38 2001/05/08 16:03:06 kowal2
49 Geometry update according to the latest technical spec.
51 Revision 1.37 2001/04/27 15:23:07 kowal2
52 Correct materian in the central part of the inner containment vessel
54 Revision 1.36 2001/04/26 06:15:12 kowal2
55 Corrected bug in the inner containment vessel (cones)
57 Revision 1.35 2001/04/24 11:17:33 kowal2
60 Revision 1.34 2001/04/23 10:20:18 hristov
61 Constant casted to avoid ambiguity
63 Revision 1.33 2001/04/20 08:16:47 kowal2
64 Protection against too small betaGamma. Thanks to Ivana and Yves.
66 Revision 1.32 2001/03/13 13:07:34 kowal2
67 Corrected bug in the TPC mother volume geometry.
70 Revision 1.31 2000/11/30 11:48:50 kowal2
71 TLorentzVector.h adde to satisfy the latest changes by Federico
73 Revision 1.30 2000/11/14 10:48:57 kowal2
74 Correct material used for TSA4. Thanks to J. Barbosa.
76 Revision 1.29 2000/11/06 17:24:10 kowal2
77 Corrected bug in the outer containment vessel and
78 the outer field cage geometry.
81 Revision 1.28 2000/11/02 16:55:24 kowal2
82 Corrected bug in the inner containment vessel geometry.
85 Revision 1.27 2000/11/02 07:24:11 kowal2
86 Correction in the TPC geometry.
87 Changes due to the new hit structure.
89 Revision 1.26 2000/10/05 16:16:29 kowal2
90 Corrections of the hit recording algorithm.
92 Revision 1.25 2000/10/02 21:28:18 fca
93 Removal of useless dependecies via forward declarations
95 Revision 1.24 2000/08/28 10:02:30 kowal2
96 Corrected bug in the StepManager
98 Revision 1.23 2000/07/10 20:57:39 hristov
99 Update of TPC code and macros by M.Kowalski
101 Revision 1.22 2000/06/30 12:07:50 kowal2
102 Updated from the TPC-PreRelease branch
104 Revision 1.21.2.4 2000/06/26 07:39:42 kowal2
105 Changes to obey the coding rules
107 Revision 1.21.2.3 2000/06/25 08:38:41 kowal2
108 Splitted from AliTPCtracking
110 Revision 1.21.2.2 2000/06/16 12:58:13 kowal2
111 Changed parameter settings
113 Revision 1.21.2.1 2000/06/09 07:15:07 kowal2
115 Defaults loaded automatically (hard-wired)
116 Optional parameters can be set via macro called in the constructor
118 Revision 1.21 2000/05/15 10:00:30 kowal2
119 Corrected bug in the TPC geometry, thanks to Ivana Hrivnacova
121 Revision 1.20 2000/04/17 09:37:33 kowal2
122 removed obsolete AliTPCDigitsDisplay.C
124 Revision 1.19.8.2 2000/04/10 08:31:52 kowal2
126 Different geometry for different sectors
127 Updated readout chambers
128 Some modifications to StepManager by J.Belikov
130 Revision 1.19.8.1 2000/04/10 07:56:53 kowal2
131 Not used anymore - removed
133 Revision 1.19 1999/11/04 17:28:07 fca
134 Correct barrel part of HV Degrader
136 Revision 1.18 1999/10/14 16:52:08 fca
137 Only use PDG codes and not GEANT ones
139 Revision 1.17 1999/10/08 06:27:23 fca
140 Corrected bug in the HV degrader geometry, thanks to G.Tabary
142 Revision 1.16 1999/10/04 13:39:54 fca
143 Correct array index problem
145 Revision 1.15 1999/09/29 09:24:34 fca
146 Introduction of the Copyright and cvs Log
151 ///////////////////////////////////////////////////////////////////////////////
153 // Time Projection Chamber version 2 -- detailed TPC and slow simulation //
157 <img src="picts/AliTPCv2Class.gif">
162 ///////////////////////////////////////////////////////////////////////////////
167 #include <TPDGCode.h>
169 #include "AliConst.h"
171 #include "AliTPCDigitsArray.h"
172 #include "AliTPCParam.h"
173 #include "AliTPCParamSR.h"
174 #include "AliTPCTrackHitsV2.h"
175 #include "AliTPCv2.h"
176 #include "TLorentzVector.h"
180 //_____________________________________________________________________________
181 AliTPCv2::AliTPCv2(const char *name, const char *title) :
185 // Standard constructor for Time Projection Chamber version 2
191 SetBufferSize(128000);
193 SetGasMixt(2,20,10,-1,0.9,0.1,0.); // Ne-CO2 90-10
199 SetSecLows(1, 2, 3, 19, 20, 21);
200 SetSecUps(37, 38, 39, 37+18, 38+18, 39+18, -1, -1, -1, -1, -1, -1);
201 SetSens(1); // sensitive strips set
204 fTPCParam->Write(fTPCParam->GetTitle());
207 //_____________________________________________________________________________
208 void AliTPCv2::CreateGeometry()
211 // Create the geometry of Time Projection Chamber version 2
215 <img src="picts/AliTPC.gif">
220 <img src="picts/AliTPCv2Tree.gif">
225 Int_t *idtmed = fIdtmed->GetArray();
236 Int_t nInnerSector = fTPCParam->GetNInnerSector()/2;
237 Int_t nOuterSector = fTPCParam->GetNOuterSector()/2;
239 // ---------------------------------------------------
240 // sector specification check
241 // ---------------------------------------------------
245 for (i = 0; i < 6; ++i) {
246 if (fSecLows[i] >= 0 && fSecLows[i] < 2*nInnerSector) {
248 printf("%s: *** SECTOR %d selected\n",ClassName(),fSecLows[i]);
253 printf("%s: *** ALL LOWER SECTORS SELECTED ***\n",ClassName());
258 printf("%s: *** ERROR: AT LEAST ONE LOWER SECTOR MUST BE SPECIFIED ***\n",ClassName());
259 printf("%s: !!! PROGRAM STOPPED !!!\n",ClassName());
265 for (i = 0; i < 12; ++i) {
266 if (fSecUps[i] > 2*nInnerSector-1 &&
267 fSecUps[i] < 2*(nInnerSector+nOuterSector)) {
268 printf("%s: *** SECTOR %d selected\n",ClassName(),fSecUps[i]);
273 printf("%s: *** ALL UPPER SECTORS SELECTED ***\n",ClassName());
278 //--------------------------------------------------------------------
281 // Mother volume TPC (Air) - all volumes will be positioned in it
336 gMC->Gsvolu("TPC ","PCON",idtmed[0],dm,27);
340 //-------------------------------------------------------------------
341 // Tpc Outer INsulator (CO2) - contains cont. vessel and field cage
342 //-------------------------------------------------------------------
384 gMC->Gsvolu("TOIN","PCON",idtmed[3],dm,21);
386 //----------------------------------------------------------------
387 // Tpc Outer Contaiment Vessel
388 // mother volume - Al, daughters - composite (sandwich)
389 //----------------------------------------------------------------
431 gMC->Gsvolu("TOCV","PCON",idtmed[4],dm,21);
433 // Daughter volumes - sandwich
435 // Tpc SAndwich 1 - Al
441 gMC->Gsvolu("TSA1","TUBE",idtmed[4],dm,3);
443 // Tpc SAndwich 2 - epoxy glue (I use Lexan)
448 gMC->Gsvolu("TSA2","TUBE",idtmed[14],dm,3);
450 // Tpc SAndwich 3 - Tedlar
455 gMC->Gsvolu("TSA3","TUBE",idtmed[9],dm,3);
458 // Tpc SAndwich 4 - fiber glass (G10)
463 gMC->Gsvolu("TSA4","TUBE",idtmed[12],dm,3);
465 // Tpc SAndwich 5 - NOMEX honeycomb
470 gMC->Gsvolu("TSA5","TUBE",idtmed[6],dm,3);
472 // 5->4->3->2->1->TCOV
475 gMC->Gspos("TSA5",1,"TSA4",0.,0.,0.,0,"ONLY");
476 gMC->Gspos("TSA4",1,"TSA3",0.,0.,0.,0,"ONLY");
477 gMC->Gspos("TSA3",1,"TSA2",0.,0.,0.,0,"ONLY");
478 gMC->Gspos("TSA2",1,"TSA1",0.,0.,0.,0,"ONLY");
480 gMC->Gspos("TSA1",1,"TOCV",0.,0.,3.,0,"ONLY");
484 gMC->Gspos("TOCV",1,"TOIN",0.,0.,0.,0,"ONLY");
486 //-------------------------------------------------------
487 // Tpc Outer Field Cage
488 // mother volume - Al, daughters - composite (sandwich)
489 //-------------------------------------------------------
531 gMC->Gsvolu("TOFC","PCON",idtmed[4],dm,21);
535 // Tpc SAndwich 6 - Tedlar
541 gMC->Gsvolu("TSA6","TUBE",idtmed[9],dm,3);
543 // Tpc SAndwich 7 - fiber glass
548 gMC->Gsvolu("TSA7","TUBE",idtmed[12],dm,3);
551 // Tpc SAndwich 8 - NOMEX
556 gMC->Gsvolu("TSA8","TUBE",idtmed[6],dm,3);
560 gMC->Gspos("TSA8",1,"TSA7",0.,0.,0.,0,"ONLY");
561 gMC->Gspos("TSA7",1,"TSA6",0.,0.,0.,0,"ONLY");
562 gMC->Gspos("TSA6",1,"TOFC",0.,0.,0.,0,"ONLY");
565 // TOFC overlaps with
567 gMC->Gspos("TOFC",1,"TOIN",0.,0.,0.,0,"ONLY");
571 gMC->Gspos("TOIN",1,"TPC ",0.,0.,0.,0,"ONLY");
575 //--------------------------------------------------------------------
576 // Tpc Inner INsulator (CO2) - inner f.c. will be placed there
577 // Inner containment vessel will be placed directly in the TPC
578 //--------------------------------------------------------------------
608 gMC->Gsvolu("TIIN","PCON",idtmed[3],dm,15);
610 // the middle part of the F.C. is thinner - carve out the strip - Ne-CO2
616 gMC->Gsvolu("TII1","TUBE",idtmed[1],dm,3);
618 gMC->Gspos("TII1",1,"TIIN",0.,0.,0.,0,"ONLY");
620 //-----------------------------------------------------
621 // Tpc Inner Field Cage
622 // mother volume - Al, daughters - composite (sandwich)
623 //------------------------------------------------------
689 gMC->Gsvolu("TIFC","PCON",idtmed[4],dm,33);
691 // daughter volumes - central part
693 // Tpc Sandwich 9 -Tedlar
699 gMC->Gsvolu("TSA9","TUBE",idtmed[9],dm,3);
701 // Tpc Sandwich 10 - fiber glass (G10)
706 gMC->Gsvolu("TS10","TUBE",idtmed[12],dm,3);
708 // Tpc Sandwich 11 - NOMEX
713 gMC->Gsvolu("TS11","TUBE",idtmed[6],dm,3);
717 gMC->Gspos("TS11",1,"TS10",0.,0.,0.,0,"ONLY");
718 gMC->Gspos("TS10",1,"TSA9",0.,0.,0.,0,"ONLY");
720 gMC->Gspos("TSA9",1,"TIFC",0.,0.,0.,0,"ONLY");
722 // daughter volumes - outer parts (reinforced)
724 // Tpc Sandwich 12 -Tedlar
730 gMC->Gsvolu("TS12","TUBE",idtmed[9],dm,3);
732 // Tpc Sandwich 13 - fiber glass (G10)
737 gMC->Gsvolu("TS13","TUBE",idtmed[12],dm,3);
739 // Tpc Sandwich 14 - NOMEX
744 gMC->Gsvolu("TS14","TUBE",idtmed[6],dm,3);
748 gMC->Gspos("TS14",1,"TS13",0.,0.,0.,0,"ONLY");
749 gMC->Gspos("TS13",1,"TS12",0.,0.,0.,0,"ONLY");
751 gMC->Gspos("TS12",1,"TIFC",0.,0.,170.05,0,"ONLY");
752 gMC->Gspos("TS12",2,"TIFC",0.,0.,-170.05,0,"ONLY");
754 // place this inside the inner insulator
756 gMC->Gspos("TIFC",1,"TIIN",0.,0.,0.,0,"ONLY");
758 // and now in the TPC...
760 gMC->Gspos("TIIN",1,"TPC ",0.,0.,0.,0,"ONLY");
762 //---------------------------------------------------------
763 // Tpc Inner Containment vessel - Cones
764 //---------------------------------------------------------
818 gMC->Gsvolu("TICC","PCON",idtmed[4],dm,27);
820 Float_t phi1,phi2,phi3,theta1,theta2,theta3; // rotation angles
831 AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
833 gMC->Gspos("TICC",1,"TPC ",0.,0.,0.,0,"ONLY");
834 gMC->Gspos("TICC",2,"TPC ",0.,0.,0.,idrotm[nRotMat],"ONLY");
837 //---------------------------------------------------------
838 // Tpc Inner Containment vessel - Middle part -Al
839 //---------------------------------------------------------
881 gMC->Gsvolu("TICM","PCON",idtmed[4],dm,21);
883 // Tpc Sandwich 15 - Al
889 gMC->Gsvolu("TS15","TUBE",idtmed[4],dm,3);
891 // Tpc Sandwich 16 - epoxy glue
896 gMC->Gsvolu("TS16","TUBE",idtmed[14],dm,3);
898 // Tpc Sandwich 17 - Tedlar
903 gMC->Gsvolu("TS17","TUBE",idtmed[9],dm,3);
905 // Tpc Sandwich 18 - carbon fiber
910 gMC->Gsvolu("TS18","TUBE",idtmed[15],dm,3);
912 // Tpc Sandwich 19 - Nomex
917 gMC->Gsvolu("TS19","TUBE",idtmed[6],dm,3);
919 // 19->18->17->16->15-> TICM
921 gMC->Gspos("TS19",1,"TS18",0.,0.,0.,0,"ONLY");
922 gMC->Gspos("TS18",1,"TS17",0.,0.,0.,0,"ONLY");
923 gMC->Gspos("TS17",1,"TS16",0.,0.,0.,0,"ONLY");
924 gMC->Gspos("TS16",1,"TS15",0.,0.,0.,0,"ONLY");
926 gMC->Gspos("TS15",1,"TICM ",0.,0.,0.,0,"ONLY");
929 // TPc inner cont. vessel Joints
935 gMC->Gsvolu("TPJ1","TUBE",idtmed[4],dm,3);
937 gMC->Gspos("TPJ1",1,"TPC ",0.,0.,72.3,0,"ONLY");
938 gMC->Gspos("TPJ1",2,"TPC ",0.,0.,-72.3,0,"ONLY");
970 gMC->Gsvolu("TPJ2","PCON",idtmed[4],dm,15);
972 gMC->Gspos("TPJ2",1,"TPC ",0.,0.,0.,0,"ONLY");
973 gMC->Gspos("TPJ2",2,"TPC ",0.,0.,0.,idrotm[nRotMat],"ONLY");
977 // Tpc Inner Containment vessel Seal (Viton, I use Lexan for a time being)
983 gMC->Gsvolu("TICS","TUBE",idtmed[14],dm,3);
985 gMC->Gspos("TICS",1,"TPC ",0.,0.,71.7,0,"ONLY");
986 gMC->Gspos("TICS",2,"TPC ",0.,0.,-71.7,0,"ONLY");
990 gMC->Gspos("TICM",1,"TPC ",0.,0.,0.,0,"ONLY");
994 nRotMat++; // prepare for the next rotation matrix
996 //---------------------------------------------------------
997 // Tpc Dift Gas volume Nonsensitive (Ne-CO2 90/10)
998 // and its daughters (HV membrane, rods, readout chambers)
999 //---------------------------------------------------------
1005 gMC->Gsvolu("TDGN","TUBE",idtmed[1],dm,3);
1007 // sector opening angles
1009 Float_t innerOpenAngle = fTPCParam->GetInnerAngle();
1010 Float_t outerOpenAngle = fTPCParam->GetOuterAngle();
1012 // sector angle shift
1014 Float_t innerAngleShift = fTPCParam->GetInnerAngleShift();
1017 // All above parameters are identical for inner and outer
1018 // sectors. The distinction is kept for the historical reasons
1019 // and eventually will disappear.
1021 Float_t tanAlpha = TMath::Tan(0.5*innerOpenAngle);
1022 Float_t cosAlpha = TMath::Sqrt(1.+tanAlpha*tanAlpha);
1025 //-------------------------------------------------------------------------
1026 // Tpc Inner Readout Chambers
1027 //-------------------------------------------------------------------------
1031 dm[2]= 1.6; // thickness
1034 gMC->Gsvolu("TIRC","TRD1",idtmed[4],dm,4);
1036 // this volume will be positioned in the empty space
1037 // of the end-cap to avoid overlaps
1044 gMC->Gsvolu("TIC1","TRD1",idtmed[4],dm,4);
1047 //------------------------------------------------
1048 // Tpc Inner readout chamber Pad Plane
1049 //------------------------------------------------
1056 gMC->Gsvolu("TIPP","TRD1",idtmed[12],dm,4);
1060 dm[0] -= 1.218511934;
1061 dm[1] -= 1.218511934;
1064 gMC->Gsvolu("TIC3","TRD1",idtmed[1],dm,4);
1066 gMC->Gspos("TIC3",1,"TIPP",0.,0.15,0.,0,"ONLY");
1068 gMC->Gspos("TIPP",1,"TIRC",0.,1.1,0.,0,"ONLY");
1071 //----------------------------------------------
1072 // Tpc Readout Chambers Empty spaces - for both
1073 // inner and outer sectors
1074 //----------------------------------------------
1076 gMC->Gsvolu("TRCE","TRD1",idtmed[0],dm,0);
1078 // Inner sector - 4 spaces
1089 space = rr*tanAlpha-dm[0];
1091 for(Int_t nsLow=0;nsLow<4;nsLow++){
1094 dm[1]= rr*tanAlpha - space;
1098 gMC->Gsposp("TRCE",nsLow+1,"TIRC",0.,-0.8,zz,0,"ONLY",dm,4);
1104 gMC->Gsposp("TRCE",nsLow+5,"TIC1",0.,1.05,zz-2.1,0,"ONLY",dm,4);
1107 dm[0] = rr*tanAlpha - space;
1113 // dm[1] - this is the dm[1] from the previous TRCE
1117 gMC->Gsposp("TRCE",9,"TIC1",0.,-1.2,0.,0,"ONLY",dm,4);
1120 // TPc Space for Connectors
1127 gMC->Gsvolu("TPSC","BOX ",idtmed[0],dm,3);
1135 gMC->Gsvolu("TPCC","BOX ",idtmed[13],dm,3);
1137 gMC->Gspos("TPCC",1,"TPSC",0.,0.15,0.,0,"ONLY");
1145 // inner part of the inner sector - 2 x 20 holes
1147 astep = 20.00096874/19.;
1149 alpha = 10.00048437-astep;
1161 for(ncon=0;ncon<20;ncon++){
1167 phi3 = (alpha>0) ? 0. : 180.;
1168 theta3 = TMath::Abs(alpha);
1170 AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
1174 gMC->Gspos("TPSC",ncon+1,"TIRC",x1,0.3,-12.7875,idrotm[nRotMat],"ONLY");
1175 gMC->Gspos("TPSC",ncon+21,"TIRC",x2,0.3,-2.8625,idrotm[nRotMat],"ONLY");
1186 // outer part of the inner sector - 2 x 25 holes
1188 astep = 20.00096874/24.;
1189 alpha = 10.00048437-astep;
1197 for(ncon=0;ncon<25;ncon++){
1203 phi3 = (alpha>0) ? 0. : 180.;
1204 theta3 = TMath::Abs(alpha);
1206 AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
1210 gMC->Gspos("TPSC",ncon+41,"TIRC",x1,0.3,7.0625,idrotm[nRotMat],"ONLY");
1211 gMC->Gspos("TPSC",ncon+66,"TIRC",x2,0.3,16.9875,idrotm[nRotMat],"ONLY");
1222 //--------------------------------------------------------------------------
1223 // TPC Outer Readout Chambers
1224 // this is NOT a final design
1225 //--------------------------------------------------------------------------
1229 dm[2]= 1.5; //thickness
1232 gMC->Gsvolu("TORC","TRD1",idtmed[4],dm,4);
1234 //------------------------------------------------
1235 // Tpc Outer readout chamber Pad Plane
1236 //------------------------------------------------
1240 gMC->Gsvolu("TOPP","TRD1",idtmed[12],dm,4);
1242 dm[0] -= 1.218511934;
1243 dm[1] -= 1.218511934;
1246 gMC->Gsvolu("TOC3","TRD1",idtmed[1],dm,4);
1248 gMC->Gspos("TOC3",1,"TOPP",0.,0.15,0.,0,"ONLY");
1250 gMC->Gspos("TOPP",1,"TORC",0.,1.0,0.,0,"ONLY");
1259 gMC->Gsposp("TRCE",10,"TORC",0.,-0.8,-2.15,0,"ONLY",dm,4);
1266 gMC->Gsvolu("TOC1","TRD1",idtmed[4],dm,4);
1273 gMC->Gsposp("TRCE",11,"TOC1",0.,0.,0.,0,"ONLY",dm,4);
1275 //-----------------------------------------------
1276 // Tpc Services Support Wheel
1277 //-----------------------------------------------
1292 gMC->Gsvolu("TSSW","PGON",idtmed[4],dm,10);
1294 // Tpc Services Wheel Cover
1299 gMC->Gsvolu("TSWC","PGON",idtmed[4],dm,10);
1301 // Tpc Service wheel Cover Empty space
1308 gMC->Gsvolu("TSCE","TRD1",idtmed[0],dm,4);
1310 // Tpc services Wheel Empty Spaces
1317 gMC->Gsvolu("TWES","TRD1",idtmed[0],dm,4);
1319 // Tpc Services Wheel Bars
1321 gMC->Gsvolu("TSWB","TRD1",idtmed[4],dm,0);
1331 gMC->Gsposp("TSWB",1,"TWES",0.,0.,-85.125,0,"ONLY",dm,4);
1336 gMC->Gsposp("TSWB",2,"TWES",0.,0.,85.125,0,"ONLY",dm,4);
1338 // TPc ELectronics - right now 30% X0 Si
1345 gMC->Gsvolu("TPEL","TRD1",idtmed[11],dm,4);
1346 gMC->Gspos("TPEL",1,"TWES",0.,0.,0.,0,"ONLY");
1348 //--------------------------------------------------------------------------
1350 //--------------------------------------------------------------------------
1352 // TPc Main Wheel - Al
1358 gMC->Gsvolu("TPMW","TUBE",idtmed[4],dm,3);
1360 //--------------------------------------------------------------------------
1361 // Tpc Empty Space for the Readout chambers
1362 //--------------------------------------------------------------------------
1366 Float_t dR = 0.5*(rUp-rLow);
1368 space= 1.5/cosAlpha; // wheel ribs are 3.0 cm wide
1370 dm[0]= rLow*tanAlpha-space;
1371 dm[1]= rUp*tanAlpha-space;
1375 gMC->Gsvolu("TESR","TRD1",idtmed[0],dm,4);
1379 gMC->Gspos("TIC1",1,"TESR",0.,0.75,-dR+23.97,0,"ONLY");
1383 gMC->Gspos("TOC1",1,"TESR",0.,0.75,dR-55.02,0,"ONLY");
1385 // Tpc Empty Space Bars - Al (daughters of TESR)
1389 gMC->Gsvolu("TESB","TRD1",idtmed[4],dm,0);
1393 dm[0]= rLow*tanAlpha-space;
1394 dm[1]= 88.7*tanAlpha-space;
1400 gMC->Gsposp("TESB",1,"TESR",0.,0.75,zBar,0,"ONLY",dm,4);
1404 dm[0]= 131.65*tanAlpha-space;
1405 dm[1]= 136.5*tanAlpha-space;
1408 zBar = -dR +131.65+dm[3]-rLow;
1410 gMC->Gsposp("TESB",2,"TESR",0.,0.75,zBar,0,"ONLY",dm,4);
1414 dm[0]= 240.4*tanAlpha-space;
1415 dm[1]= rUp*tanAlpha-space;
1420 gMC->Gsposp("TESB",3,"TESR",0.,0.75,zBar,0,"ONLY",dm,4);
1422 //------------------------------------------------------
1423 // TPc Lower "S" Sectors
1424 //------------------------------------------------------
1427 Float_t inSecLowEdge = fTPCParam->GetInnerRadiusLow();
1428 Float_t inSecUpEdge = fTPCParam->GetInnerRadiusUp();
1430 dm[0] = inSecLowEdge*TMath::Tan(0.5*innerOpenAngle)-0.01;
1431 dm[1] = inSecUpEdge*TMath::Tan(0.5*innerOpenAngle)-0.01;
1432 dm[2] = 0.5*(250. - 5.e-3);
1433 dm[3] = 0.5*(inSecUpEdge-inSecLowEdge);
1435 gMC->Gsvolu("TPLS", "TRD1", idtmed[2], dm, 4); // sensitive
1438 //----------------------------------------------------------
1439 // TPc Upper Sectors
1440 //----------------------------------------------------------
1442 Float_t ouSecLowEdge = fTPCParam->GetOuterRadiusLow();
1443 Float_t ouSecUpEdge = fTPCParam->GetOuterRadiusUp();
1445 dm[0] = ouSecLowEdge*TMath::Tan(0.5*outerOpenAngle)-0.01;
1446 dm[1] = ouSecUpEdge*TMath::Tan(0.5*outerOpenAngle)-0.01;
1447 dm[2] = 0.5*(250. - 5.e-3);
1448 dm[3] = 0.5*(ouSecUpEdge-ouSecLowEdge);
1450 gMC->Gsvolu("TPUS", "TRD1", idtmed[2], dm, 4); // sensitive
1456 gMC->Gsvolu("TPSS","TRD1",idtmed[2],dm,0); // sensitive
1458 Int_t nofStrips,nstr;
1460 Float_t stripThick = 0.01; // 100 microns
1466 // if all lower sectors selected define only 1 strip
1468 nofStrips=((fSecAL <0)||(fSecAL>=0 && fSens<0)) ? 1 : fTPCParam->GetNRowLow();
1469 deadSpace = fTPCParam->GetInnerWireMount();
1471 dm[2] = 0.5*(250. - 5.e-3);
1472 dm[3] = 0.5 * stripThick;
1474 for(nstr=0;nstr<nofStrips;nstr++){
1476 r1 = fTPCParam->GetPadRowRadiiLow(nstr);
1477 r2 = r1 + stripThick;
1478 dm[0] = r1 * TMath::Tan(0.5*innerOpenAngle) - deadSpace;
1479 dm[1] = r2 * TMath::Tan(0.5*innerOpenAngle) - deadSpace;
1480 zs = -inSecLowEdge -0.5*(inSecUpEdge-inSecLowEdge);
1484 gMC->Gsposp("TPSS", nstr+1, "TPLS", 0., 0., zs, 0, "ONLY", dm, 4);
1489 // strips only if several upper sectors selected end fSens > 0
1491 if(fSecAU >=0 && fSens >0){
1493 Int_t nsSave = nofStrips;
1497 nofStrips = fTPCParam->GetNRowUp();
1498 deadSpace = fTPCParam->GetOuterWireMount();
1500 dm[2] = 0.5*(250. - 5.e-3);
1501 dm[3] = 0.5 * stripThick;
1504 for(nstr=0;nstr<nofStrips;nstr++){
1506 r1 = fTPCParam->GetPadRowRadiiUp(nstr);
1507 r2 = r1 + stripThick;
1508 dm[0] = r1 * TMath::Tan(0.5*outerOpenAngle) - deadSpace;
1509 dm[1] = r2 * TMath::Tan(0.5*outerOpenAngle) - deadSpace;
1510 zs = -ouSecLowEdge -0.5*(ouSecUpEdge-ouSecLowEdge);
1514 gMC->Gsposp("TPSS", nstr+1+nsSave, "TPUS", 0., 0., zs, 0, "ONLY", dm, 4);
1520 //-------------------------------------------------------
1521 // positioning of the empty spaces into the main wheel
1522 // and readout chambers and sectors into the drift gas
1523 //-------------------------------------------------------
1525 Float_t rCenter,xc,yc;
1526 Float_t rInner,rOuter; // center of the inner and outer chamber
1534 for(Int_t ns=0; ns<nInnerSector;ns++){
1536 phi1 = ns * innerOpenAngle + innerAngleShift;
1537 phi1 *= kRaddeg; // in degrees
1539 phi1 = (Float_t)TMath::Nint(phi1) + 270.;
1541 if (phi1 > 360.) phi1 -= 360.;
1546 phi3 = ns * innerOpenAngle + innerAngleShift;
1547 phi3 *= kRaddeg; // in degrees
1549 phi3 = (Float_t)TMath::Nint(phi3);
1551 if(phi3 > 360.) phi3 -= 360.;
1555 // "holes"->End plate
1557 xc = rCenter*TMath::Cos(phi3*kDegrad);
1558 yc = rCenter*TMath::Sin(phi3*kDegrad);
1560 AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
1562 gMC->Gspos("TESR",ns+1,"TPMW",xc,yc,0.,idrotm[nRotMat],"ONLY");
1564 // TSCE->TSWC (services wheel volumes)
1566 xc = 166.142*TMath::Cos(phi3*kDegrad);
1567 yc = 166.142*TMath::Sin(phi3*kDegrad);
1569 gMC->Gspos("TSCE",ns+1,"TSWC",xc,yc,0.,idrotm[nRotMat],"ONLY");
1570 gMC->Gspos("TWES",ns+1,"TSSW",xc,yc,0.,idrotm[nRotMat],"ONLY");
1573 // readout chambers->TDGN (drift gas)
1575 xc = rInner*TMath::Cos(phi3*kDegrad);
1576 yc = rInner*TMath::Sin(phi3*kDegrad);
1578 gMC->Gspos("TIRC",ns+1,"TDGN",xc,yc,252.,idrotm[nRotMat],"ONLY");
1580 // here lower sectors
1584 // all lower sectors are positioned
1586 gMC->Gspos("TPLS",ns+1,"TDGN",xc,yc,125.0025,idrotm[nRotMat],"ONLY");
1588 Gspos("TPLS",ns+nInnerSector+1,"TDGN",xc,yc,-125.0025,idrotm[nRotMat],"ONLY");
1592 // only selected sectors are positioned (up to 6 sectors)
1594 for(Int_t sel=0;sel<6;sel++){
1596 if(fSecLows[sel] == ns){
1597 gMC->Gspos("TPLS",ns+1,"TDGN",xc,yc,125.0025,idrotm[nRotMat],"ONLY");
1599 else if(fSecLows[sel] == ns+nInnerSector){
1601 Gspos("TPLS",ns+nInnerSector+1,"TDGN",xc,yc,-125.0025,idrotm[nRotMat],"ONLY");
1604 } // lower sectors finished
1607 xc = rOuter*TMath::Cos(phi3*kDegrad);
1608 yc = rOuter*TMath::Sin(phi3*kDegrad);
1610 gMC->Gspos("TORC",ns+1,"TDGN",xc,yc,252.1,idrotm[nRotMat],"ONLY");
1612 // here upper sectors
1616 // all upper sectors
1618 gMC->Gspos("TPUS",ns+1,"TDGN",xc,yc,125.0025,idrotm[nRotMat],"ONLY");
1620 Gspos("TPUS",ns+nOuterSector+1,"TDGN",xc,yc,-125.0025,idrotm[nRotMat],"ONLY");
1624 // only selected sectors (up to 12)
1626 for(Int_t sel=0;sel<12;sel++){
1627 if(fSecUps[sel] == ns+2*nInnerSector){
1628 gMC->Gspos("TPUS",ns+1,"TDGN",xc,yc,125.0025,idrotm[nRotMat],"ONLY");
1630 else if(fSecUps[sel] == ns+2*nInnerSector+nOuterSector){
1632 Gspos("TPUS",ns+nOuterSector+1,"TDGN",xc,yc,-125.0025,idrotm[nRotMat],"ONLY");
1635 } // upper sectors finished
1640 theta2 = 0.; // reflection
1642 AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
1644 xc = rInner*TMath::Cos(phi3*kDegrad);
1645 yc = rInner*TMath::Sin(phi3*kDegrad);
1647 gMC->Gspos("TIRC",ns+nInnerSector+1,"TDGN",xc,yc,-252.,idrotm[nRotMat],"ONLY");
1649 xc = rOuter*TMath::Cos(phi3*kDegrad);
1650 yc = rOuter*TMath::Sin(phi3*kDegrad);
1652 gMC->Gspos("TORC",ns+nOuterSector+1,"TDGN",xc,yc,-252.1,idrotm[nRotMat],"ONLY");
1659 gMC->Gspos("TPMW",1,"TPC ",0.,0.,256.6,0,"ONLY");
1660 gMC->Gspos("TPMW",2,"TPC ",0.,0.,-256.6,idrotm[0],"ONLY");
1662 //---------------------------------------------------------
1663 // Tpc High Voltage Membrane - 100 microns of mylar
1664 //---------------------------------------------------------
1670 gMC->Gsvolu("THVM","TUBE",idtmed[8],dm,3);
1672 gMC->Gspos("THVM",1,"TDGN",0.,0.,0.,0,"ONLY");
1674 // Tpc High Voltage membrane Holders
1676 gMC->Gsvolu("THVH","TUBE",idtmed[4],dm,0);
1686 gMC->Gsposp("THVH",1,"TDGN",0.,0.,0.,0,"ONLY",dm,3);
1694 gMC->Gsposp("THVH",2,"TDGN",0.,0.,0.,0,"ONLY",dm,3);
1696 //----------------------------------------------------------
1697 // TPc Support Rods - MAKROLON
1698 //----------------------------------------------------------
1703 gMC->Gsvolu("TPSR","TUBE",idtmed[7],dm,0); // inner and outer rods differ
1706 for(Int_t nrod=0;nrod<18;nrod++){
1707 Float_t angle=innerOpenAngle*(Float_t)nrod;
1709 xc=81.5*TMath::Cos(angle);
1710 yc=81.5*TMath::Sin(angle);
1714 gMC->Gsposp("TPSR",nrod+1,"TDGN",xc,yc,126.9,0,"ONLY",dm,3);
1715 gMC->Gsposp("TPSR",nrod+19,"TDGN",xc,yc,-126.9,0,"ONLY",dm,3);
1719 xc=254.25*TMath::Cos(angle);
1720 yc=254.25*TMath::Sin(angle);
1722 // rod number 54 contans the HV cable
1725 gMC->Gsposp("TPSR",nrod+37,"TDGN",xc,yc,127.,0,"ONLY",dm,3);
1726 gMC->Gsposp("TPSR",nrod+54,"TDGN",xc,yc,-127.,0,"ONLY",dm,3);
1731 //----------------------------------------------------------
1732 // Tpc High Voltage Rod - MAKROLON + Copper cable
1733 //----------------------------------------------------------
1735 // rod with cable (Left)
1741 gMC->Gsvolu("THVL","TUBE",idtmed[7],dm,3);
1749 gMC->Gsvolu("THVC","TUBE",idtmed[10],dm,3);
1757 gMC->Gsvolu("THVE","TUBE",idtmed[1],dm,3);
1759 gMC->Gspos("THVC",1,"THVL",0.,0.,0.,0,"ONLY");
1760 gMC->Gspos("THVE",1,"THVL",0.,0.,0.,0,"ONLY");
1762 // rod without cable
1768 gMC->Gsvolu("THVR","TUBE",idtmed[7],dm,3);
1770 gMC->Gspos("THVL",1,"TDGN",xc,yc,-127.,0,"ONLY");
1771 gMC->Gspos("THVR",1,"TDGN",xc,yc,127.,0,"ONLY");
1773 gMC->Gspos("TDGN",1,"TPC ",0.,0.,0.,0,"ONLY");
1775 // services wheel cover -> wheel
1778 gMC->Gspos("TSWC",1,"TSSW",0.,0.,4.5,0,"ONLY");
1779 gMC->Gspos("TSWC",2,"TSSW",0.,0.,-4.5,0,"ONLY");
1782 // put the wheel into the TPC
1784 gMC->Gspos("TSSW",1,"TPC ",0.,0.,278.7,0,"ONLY");
1785 gMC->Gspos("TSSW",2,"TPC ",0.,0.,-278.7,0,"ONLY");
1789 gMC->Gsord("TPMW",6);
1790 gMC->Gsord("TSSW",6);
1791 gMC->Gsord("TSWC",6);
1792 if(fSecAL >=0) gMC->Gsord("TPLS",3);
1793 if(fSecAU >=0 && fSens >0) gMC->Gsord("TPUS",3);
1794 gMC->Gsord("TDGN",6);
1796 // put the TPC into ALIC (main mother volume)
1798 gMC->Gspos("TPC ",1,"ALIC",0.,0.,0.,0,"ONLY");
1802 } // end of function
1804 //_____________________________________________________________________________
1805 void AliTPCv2::DrawDetector()
1808 // Draw a shaded view of the Time Projection Chamber version 1
1811 // Set everything unseen
1812 gMC->Gsatt("*", "seen", -1);
1814 // Set ALIC mother transparent
1815 gMC->Gsatt("ALIC","SEEN",0);
1817 // Set the volumes visible
1820 gMC->Gsatt("TPC ","SEEN",0);
1821 gMC->Gsatt("TOIN","SEEN",1);
1822 gMC->Gsatt("TOIN","COLO",7);
1823 gMC->Gsatt("TOCV","SEEN",1);
1824 gMC->Gsatt("TOCV","COLO",4);
1825 gMC->Gsatt("TSA1","SEEN",0);
1826 gMC->Gsatt("TSA2","SEEN",0);
1827 gMC->Gsatt("TSA3","SEEN",0);
1828 gMC->Gsatt("TSA4","SEEN",0);
1829 gMC->Gsatt("TSA5","SEEN",0);
1830 gMC->Gsatt("TOFC","SEEN",1);
1831 gMC->Gsatt("TOFC","COLO",4);
1832 gMC->Gsatt("TSA6","SEEN",0);
1833 gMC->Gsatt("TSA7","SEEN",0);
1834 gMC->Gsatt("TSA8","SEEN",0);
1835 gMC->Gsatt("TIIN","SEEN",1);
1836 gMC->Gsatt("TIIN","COLO",7);
1837 gMC->Gsatt("TII1","SEEN",0);
1838 gMC->Gsatt("TIFC","SEEN",1);
1839 gMC->Gsatt("TIFC","COLO",4);
1840 gMC->Gsatt("TSA9","SEEN",0);
1841 gMC->Gsatt("TS10","SEEN",0);
1842 gMC->Gsatt("TS11","SEEN",0);
1843 gMC->Gsatt("TS12","SEEN",0);
1844 gMC->Gsatt("TS13","SEEN",0);
1845 gMC->Gsatt("TS14","SEEN",0);
1846 gMC->Gsatt("TICC","SEEN",0);
1847 gMC->Gsatt("TICM","SEEN",0);
1848 gMC->Gsatt("TS15","SEEN",0);
1849 gMC->Gsatt("TS16","SEEN",0);
1850 gMC->Gsatt("TS17","SEEN",0);
1851 gMC->Gsatt("TS18","SEEN",0);
1852 gMC->Gsatt("TS19","SEEN",0);
1853 gMC->Gsatt("TPJ1","SEEN",0);
1854 gMC->Gsatt("TPJ2","SEEN",0);
1855 gMC->Gsatt("TICS","SEEN",0);
1856 gMC->Gsatt("TDGN","SEEN",0);
1857 gMC->Gsatt("TIRC","SEEN",0);
1858 gMC->Gsatt("TIC1","SEEN",1);
1859 gMC->Gsatt("TIPP","SEEN",0);
1860 gMC->Gsatt("TIC3","SEEN",0);
1861 gMC->Gsatt("TRCE","SEEN",0);
1862 gMC->Gsatt("TPSC","SEEN",0);
1863 gMC->Gsatt("TPCC","SEEN",0);
1864 gMC->Gsatt("TORC","SEEN",0);
1865 gMC->Gsatt("TOPP","SEEN",0);
1866 gMC->Gsatt("TOC3","SEEN",0);
1867 gMC->Gsatt("TOC1","SEEN",1);
1868 gMC->Gsatt("TSSW","SEEN",1);
1869 gMC->Gsatt("TSWC","SEEN",1);
1870 gMC->Gsatt("TSSW","COLO",3);
1871 gMC->Gsatt("TSWC","COLO",3);
1872 gMC->Gsatt("TSCE","COLO",6);
1873 gMC->Gsatt("TSCE","SEEN",1);
1874 gMC->Gsatt("TWES","SEEN",0);
1875 gMC->Gsatt("TSWB","SEEN",0);
1876 gMC->Gsatt("TPEL","SEEN",0);
1877 gMC->Gsatt("TPMW","SEEN",1);
1878 gMC->Gsatt("TESR","SEEN",1);
1879 gMC->Gsatt("TPMW","COLO",12);
1880 gMC->Gsatt("TIC1","COLO",5);
1881 gMC->Gsatt("TOC1","COLO",5);
1882 gMC->Gsatt("TESB","SEEN",0);
1883 gMC->Gsatt("THVM","SEEN",1);
1884 gMC->Gsatt("THVM","COLO",11);
1885 gMC->Gsatt("THVH","SEEN",0);
1886 gMC->Gsatt("TPSR","SEEN",0);
1887 gMC->Gsatt("THVL","SEEN",0);
1888 gMC->Gsatt("THVC","SEEN",0);
1889 gMC->Gsatt("THVE","SEEN",0);
1890 gMC->Gsatt("THVR","SEEN",0);
1891 gMC->Gsatt("TPSS","SEEN",0);
1892 gMC->Gsatt("TPUS","SEEN",0);
1893 gMC->Gsatt("TPLS","SEEN",0);
1896 gMC->Gdopt("hide", "on");
1897 gMC->Gdopt("shad", "on");
1898 gMC->Gsatt("*", "fill", 7);
1899 gMC->SetClipBox(".");
1900 gMC->SetClipBox("TPMW",-300,300,-300,300,254.,270.);
1901 gMC->SetClipBox("TESR",-300,300,-300,300,254.,270.);
1902 gMC->SetClipBox("TSSW",-300,300,-300,300,283.,284.);
1903 gMC->SetClipBox("TSWC",-300,300,-300,300,283.,284.);
1904 gMC->SetClipBox("*", 0, 300, -300, 300, -290, 290);
1905 gMC->DefaultRange();
1906 gMC->Gdraw("alic", 40, 30, 0, 12, 9.5, .025, .025);
1907 gMC->Gdhead(1111, "Time Projection Chamber");
1908 gMC->Gdman(18, 4, "MAN");
1909 gMC->Gdopt("hide","off");
1912 //_____________________________________________________________________________
1913 void AliTPCv2::CreateMaterials()
1916 // Define materials for version 2 of the Time Projection Chamber
1919 AliTPC::CreateMaterials();
1922 //_____________________________________________________________________________
1923 void AliTPCv2::Init()
1926 // Initialises version 2 of the TPC after that it has been built
1929 Int_t *idtmed = fIdtmed->GetArray();
1935 fIdSens=gMC->VolId("TPSS");
1937 fIdLSec=gMC->VolId("TPLS"); // lower sector
1938 fIdUSec=gMC->VolId("TPUS"); // upper sector
1940 gMC->SetMaxNStep(30000); // max. number of steps increased
1942 gMC->Gstpar(idtmed[2],"LOSS",5); // specific energy loss
1944 printf("%s: *** TPC version 2 initialized ***\n",ClassName());
1945 printf("%s: Maximum number of steps = %d\n",ClassName(),gMC->GetMaxNStep());
1951 //_____________________________________________________________________________
1952 void AliTPCv2::StepManager()
1955 // Called for every step in the Time Projection Chamber
1959 // parameters used for the energy loss calculations
1961 const Float_t kprim = 14.35; // number of primary collisions per 1 cm
1962 const Float_t kpoti = 20.77e-9; // first ionization potential for Ne/CO2
1963 const Float_t kwIon = 35.97e-9; // energy for the ion-electron pair creation
1966 const Float_t kbig = 1.e10;
1973 vol[1]=0; // preset row number to 0
1977 gMC->SetMaxStep(kbig);
1979 if(!gMC->IsTrackAlive()) return; // particle has disappeared
1981 Float_t charge = gMC->TrackCharge();
1983 if(TMath::Abs(charge)<=0.) return; // take only charged particles
1985 // check the sensitive volume
1987 id = gMC->CurrentVolID(copy); // current volume Id
1989 if ( (gMC->IsTrackEntering() || gMC->IsTrackExiting()) &&
1990 ((id == fIdLSec) || (id == fIdUSec)) ) {
1992 AddTrackReference(gAlice->CurrentTrack());
1996 vol[0] = copy-1; // lower sector number
1998 else if(id == fIdUSec){
1999 vol[0] = copy+fTPCParam->GetNInnerSector()-1; // upper sector number
2001 else if(id == fIdSens && gMC->IsTrackEntering()){
2003 // track is entering the sensitive strip
2005 vol[1]= copy-1; // row number (absolute)
2009 id = gMC->CurrentVolOffID(1,copy);
2015 vol[0] = copy-1; // sector number
2022 vol[0] = copy-1+fTPCParam->GetNInnerSector(); // sector number
2023 vol[1] -= fTPCParam->GetNRowLow(); // row number (starts also from 0)
2029 // because Jouri wants to have this
2031 gMC->TrackMomentum(p);
2035 hits[3]=0.; // this hit has no energy loss
2036 // new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
2038 AddHit(gAlice->CurrentTrack(), vol,hits); //MI change
2042 gMC->TrackPosition(p);
2046 hits[3]=0.; // this hit has no energy loss
2047 // new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
2049 AddHit(gAlice->CurrentTrack(), vol,hits); //MI change
2054 //-----------------------------------------------------------------
2055 // charged particle is in the sensitive volume
2056 //-----------------------------------------------------------------
2058 if(gMC->TrackStep() > 0) {
2060 Int_t nel = (Int_t)(((gMC->Edep())-kpoti)/kwIon) + 1;
2061 nel=TMath::Min(nel,300); // 300 electrons corresponds to 10 keV
2063 gMC->TrackPosition(p);
2067 hits[3]=(Float_t)nel;
2071 // new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
2073 gMC->TrackMomentum(p);
2074 Float_t momentum = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
2075 Float_t precision = (momentum>0.1) ? 0.002 :0.01;
2076 fTrackHits->SetHitPrecision(precision);
2078 AddHit(gAlice->CurrentTrack(), vol,hits); //MI change
2082 // Stemax calculation for the next step
2086 gMC->TrackMomentum(mom);
2087 Float_t ptot=mom.Rho();
2088 Float_t betaGamma = ptot/gMC->TrackMass();
2090 Int_t pid=gMC->TrackPid();
2091 if((pid==kElectron || pid==kPositron) && ptot > 0.002)
2093 pp = kprim*1.58; // electrons above 20 MeV/c are on the plateau!
2098 betaGamma = TMath::Max(betaGamma,(Float_t)7.e-3); // protection against too small bg
2099 pp=kprim*BetheBloch(betaGamma);
2101 if(TMath::Abs(charge) > 1.) pp *= (charge*charge);
2104 Double_t rnd = gMC->GetRandom()->Rndm();
2106 gMC->SetMaxStep(-TMath::Log(rnd)/pp);
2110 //_____________________________________________________________________________
2111 Float_t AliTPCv2::BetheBloch(Float_t bg)
2114 // Bethe-Bloch energy loss formula
2116 const Double_t kp1=0.76176e-1;
2117 const Double_t kp2=10.632;
2118 const Double_t kp3=0.13279e-4;
2119 const Double_t kp4=1.8631;
2120 const Double_t kp5=1.9479;
2122 Double_t dbg = (Double_t) bg;
2124 Double_t beta = dbg/TMath::Sqrt(1.+dbg*dbg);
2126 Double_t aa = TMath::Power(beta,kp4);
2127 Double_t bb = TMath::Power(1./dbg,kp5);
2129 bb=TMath::Log(kp3+bb);
2131 return ((Float_t)((kp2-aa-bb)*kp1/aa));