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 1.16 2000/04/17 09:37:33 kowal2
19 removed obsolete AliTPCDigitsDisplay.C
21 Revision 1.15.8.2 2000/04/10 08:29:48 kowal2
23 Different pad geometry for different sectors
24 Updated readouch chambers geometry
26 Revision 1.15.8.1 2000/04/10 07:56:53 kowal2
27 Not used anymore - removed
29 Revision 1.15 1999/11/04 17:28:07 fca
30 Correct barrel part of HV Degrader
32 Revision 1.14 1999/10/08 06:27:23 fca
33 Corrected bug in the HV degrader geometry, thanks to G.Tabary
35 Revision 1.13 1999/10/04 13:39:54 fca
36 Correct array index problem
38 Revision 1.12 1999/09/29 09:24:34 fca
39 Introduction of the Copyright and cvs Log
43 ///////////////////////////////////////////////////////////////////////////////
45 // Time Projection Chamber version 1 -- detailed TPC and fast simulation //
49 <img src="picts/AliTPCv1Class.gif">
54 ///////////////////////////////////////////////////////////////////////////////
57 #include <TGeometry.h>
69 #include "AliTPCParam.h"
70 #include "AliTPCDigitsArray.h"
74 //_____________________________________________________________________________
75 AliTPCv1::AliTPCv1(const char *name, const char *title)
76 :AliTPC(name, title) {
78 // Standard constructor for Time Projection Chamber
83 //_____________________________________________________________________________
84 void AliTPCv1::CreateGeometry()
87 // Creates geometry for Time Projection Chamber version 1
88 // Detailed geometry -- Fast simulation
93 <img src="picts/AliTPCv1.gif">
98 <img src="picts/AliTPCv1Tree.gif">
103 Int_t *idtmed = fIdtmed->GetArray();
111 // ----------------------------------------------------
112 // FIELD CAGE WITH ENDCAPS - G10
113 // THIS IS ALSO A TPC MOTHER VOLUME
114 // ----------------------------------------------------
120 gMC->Gsvolu("TPC ", "TUBE", idtmed[8], dm, 3);
122 //-----------------------------------------------------
123 // Endcap cover c-fibre 0.86% X0
124 //-----------------------------------------------------
130 gMC->Gsvolu("TPEC","TUBE",idtmed[10],dm,3);
132 //-----------------------------------------------------
133 // Drift gas , leave 2 cm at the outer radius
135 //-----------------------------------------------------
141 gMC->Gsvolu("TGAS", "TUBE", idtmed[3], dm, 3);
144 //------------------------------------------------------
145 // membrane holder - carbon fiber
146 //------------------------------------------------------
149 gMC->Gsvolu("TPMH","TUBE",idtmed[6],dm,0);
155 gMC->Gsposp("TPMH",1,"TGAS",0.,0.,0.,0,"ONLY",dm,3);
161 gMC->Gsposp("TPMH",2,"TGAS",0.,0.,0.,0,"ONLY",dm,3);
163 //----------------------------------------------------------
164 // HV membrane - 25 microns of mylar
165 //----------------------------------------------------------
171 gMC->Gsvolu("TPHV","TUBE",idtmed[5],dm,3);
173 gMC->Gspos("TPHV",1,"TGAS",0.,0.,0.,0,"ONLY");
175 gMC->Gspos("TGAS",1,"TPC ",0.,0.,0.,0,"ONLY");
177 //----------------------------------------------------------
178 // "side" gas volume, the same as the drift gas
179 // the readout chambers are placed there.
180 //----------------------------------------------------------
184 dm[2] = 0.5*(275. - 250.);
186 gMC->Gsvolu("TPSG", "TUBE", idtmed[2], dm, 3);
188 Float_t z_side = dm[2]; // 1/2 of the side gas thickness
190 //-----------------------------------------------------------
191 // Readout chambers , 25% of X0, I use Al as the material
192 //-----------------------------------------------------------
194 Float_t InnerOpenAngle = fTPCParam->GetInnerAngle();
195 Float_t OuterOpenAngle = fTPCParam->GetOuterAngle();
197 Float_t InnerAngleShift = fTPCParam->GetInnerAngleShift();
198 Float_t OuterAngleShift = fTPCParam->GetOuterAngleShift();
201 Int_t nInnerSector = fTPCParam->GetNInnerSector()/2;
202 Int_t nOuterSector = fTPCParam->GetNOuterSector()/2;
205 Float_t InSecLowEdge = fTPCParam->GetInnerRadiusLow();
206 Float_t InSecUpEdge = fTPCParam->GetInnerRadiusUp();
208 Float_t OuSecLowEdge = fTPCParam->GetOuterRadiusLow();
209 Float_t OuSecUpEdge = fTPCParam->GetOuterRadiusUp();
211 Float_t SecThick = 2.225; // Al
215 Float_t LowEdge = fTPCParam->GetInnerFrameSpace();
217 dm[0] = InSecLowEdge*TMath::Tan(0.5*InnerOpenAngle)-LowEdge;
218 dm[1] = InSecUpEdge*TMath::Tan(0.5*InnerOpenAngle)-LowEdge;
219 dm[2] = 0.5*SecThick;
220 dm[3] = 0.5*(InSecUpEdge-InSecLowEdge);
222 Float_t xCenterS = InSecLowEdge+dm[3];
224 gMC->Gsvolu("TRCS", "TRD1", idtmed[0], dm, 4);
228 Float_t UpEdge = fTPCParam->GetOuterFrameSpace();
230 dm[0] = OuSecLowEdge*TMath::Tan(0.5*OuterOpenAngle)-UpEdge;
231 dm[1] = OuSecUpEdge*TMath::Tan(0.5*OuterOpenAngle)-UpEdge;
232 dm[2] = 0.5*SecThick;
233 dm[3] = 0.5*(OuSecUpEdge-OuSecLowEdge);
235 Float_t xCenterL = OuSecLowEdge+dm[3];
237 gMC->Gsvolu("TRCL", "TRD1", idtmed[0], dm, 4);
239 Float_t z1 = -z_side + SecThick*0.5;
241 //------------------------------------------------------------------
242 // S sectors - "gas sectors" (TRD1)
243 //------------------------------------------------------------------
245 dm[0] = InSecLowEdge*TMath::Tan(0.5*InnerOpenAngle)-0.01;
246 dm[1] = InSecUpEdge*TMath::Tan(0.5*InnerOpenAngle)-0.01;
247 dm[2] = 0.5*(250. - 0.001);
248 dm[3] = 0.5*(InSecUpEdge-InSecLowEdge);
250 gMC->Gsvolu("TSGA", "TRD1", idtmed[3], dm, 4); // nonsensitive
252 //------------------------------------------------------------------
253 // sensitive strips - "pad rows"
254 //------------------------------------------------------------------
259 Float_t StripThick = 0.01; // 100 microns
262 gMC->Gsvolu("TSST", "TRD1", idtmed[4], dm, 0);
264 dm[2] = 0.5*(250. - 0.002);
265 dm[3] = 0.5 * StripThick;
270 dead = fTPCParam->GetInnerWireMount();
272 for (ns = 0; ns < fTPCParam->GetNRowLow(); ns++) {
274 r1 = fTPCParam->GetPadRowRadiiLow(ns);
275 r2 = r1 + StripThick;
276 dm[0] = r1 * TMath::Tan(0.5*InnerOpenAngle) - dead;
277 dm[1] = r2 * TMath::Tan(0.5*InnerOpenAngle) - dead;
279 zz = -InSecLowEdge -0.5*(InSecUpEdge-InSecLowEdge);
283 gMC->Gsposp("TSST", ns+1, "TSGA", 0., 0., zz, 0, "ONLY", dm, 4);
288 //-----------------------------------------------------------------
289 // L sectors - "gas sectors" (PGON to avoid overlaps)
290 //-----------------------------------------------------------------
292 dm[0] = 360.*kDegrad - 0.5*OuterOpenAngle;
294 dm[0] = (Float_t)TMath::Nint(dm[0]);
296 dm[1] = OuterOpenAngle*kRaddeg;
297 dm[1] = (Float_t)TMath::Nint(dm[1]);
303 dm[5] = OuSecLowEdge;
304 dm[6] = 252.*TMath::Cos(0.5*OuterOpenAngle)-0.002;
311 dm[11] = OuSecLowEdge;
312 dm[12] = OuSecUpEdge;
318 gMC->Gsvolu("TLGA","PGON",idtmed[3],dm,16);
320 //------------------------------------------------------------------
321 // sensitive strips - "pad rows"
322 //------------------------------------------------------------------
324 Float_t rmax = dm[6];
328 gMC->Gsvolu("TLST", "PGON", idtmed[4], dm, 0);
330 dm[0] = 360.*kDegrad - 0.5*OuterOpenAngle;
332 dm[0] = (Float_t)TMath::Nint(dm[0]);
334 dm[1] = OuterOpenAngle*kRaddeg;
335 dm[1] = (Float_t)TMath::Nint(dm[1]);
342 dead = fTPCParam->GetOuterWireMount();
344 Float_t xx = dead/TMath::Tan(0.5*OuterOpenAngle);
346 for(ns=0;ns<fTPCParam->GetNRowUp();ns++){
348 r1 = fTPCParam->GetPadRowRadiiUp(ns)-xx;
349 r2 = r1 + StripThick;
364 gMC->Gsposp("TLST",ns+1,"TLGA",xx,0.,0.,0,"ONLY",dm,10);
368 //------------------------------------------------------------------
369 // Positioning of the S-sector readout chambers
370 //------------------------------------------------------------------
372 Float_t zs = 0.5*(250.+0.002);
374 Float_t theta1,theta2,theta3;
375 Float_t phi1,phi2,phi3;
379 for(ns=0;ns<nInnerSector;ns++){
381 phi1 = ns * InnerOpenAngle + 270.*kDegrad + InnerAngleShift;
382 phi1 *= kRaddeg; // in degrees
384 phi1 = (Float_t)TMath::Nint(phi1);
386 if (phi1 > 360.) phi1 -= 360.;
392 phi3 = ns * InnerOpenAngle + InnerAngleShift;
393 phi3 *= kRaddeg; // in degrees
395 phi3 = (Float_t)TMath::Nint(phi3);
397 if(phi3 > 360.) phi3 -= 360.;
401 alpha = phi3*kDegrad;
403 x = xCenterS * TMath::Cos(alpha);
404 y = xCenterS * TMath::Sin(alpha);
406 AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
408 gMC->Gspos("TRCS", ns+1, "TPSG", x, y, z1, idrotm[nRotMat], "ONLY");
410 gMC->Gspos("TSGA",ns+1,"TGAS",x,y,zs,idrotm[nRotMat], "ONLY");
411 gMC->Gspos("TSGA",ns+1+nInnerSector,"TGAS",x,y,-zs,idrotm[nRotMat], "ONLY");
417 //-------------------------------------------------------------------
418 // Positioning of the L-sectors readout chambers
419 //-------------------------------------------------------------------
421 for(ns=0;ns<nOuterSector;ns++){
422 phi1 = ns * OuterOpenAngle + 270.*kDegrad + OuterAngleShift;
423 phi1 *= kRaddeg; // in degrees
425 phi1 = (Float_t)TMath::Nint(phi1);
428 if (phi1 > 360.) phi1 -= 360.;
433 phi3 = ns * OuterOpenAngle+OuterAngleShift;
434 phi3 *= kRaddeg; // in degrees
436 phi3 = (Float_t)TMath::Nint(phi3);
439 if(phi3 > 360.) phi3 -= 360.;
443 alpha = phi3*kDegrad;
445 x = xCenterL * TMath::Cos(alpha);
446 y = xCenterL * TMath::Sin(alpha);
448 AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
451 gMC->Gspos("TRCL", ns+1, "TPSG", x, y, z1, idrotm[nRotMat], "ONLY");
457 //-------------------------------------------------------------------
458 // Positioning of the L-sectors (gas sectors)
459 //-------------------------------------------------------------------
461 for(ns=0;ns<nOuterSector;ns++){
463 phi1 = ns*OuterOpenAngle + OuterAngleShift;
466 phi1 = (Float_t)TMath::Nint(phi1);
467 if(phi1>360.) phi1 -= 360.;
472 if(phi2>360.) phi2 -= 360.;
479 alpha = phi1*kDegrad;
482 AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
485 gMC->Gspos("TLGA",ns+1,"TGAS" ,0.,0.,0.,idrotm[nRotMat],"ONLY");
494 AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
496 gMC->Gspos("TLGA",ns+1+nOuterSector,"TGAS" ,0.,0.,0.,idrotm[nRotMat],"ONLY");
501 Float_t z0 = z_side - 0.95;
503 gMC->Gspos("TPEC",1,"TPSG",0.,0.,z0,0,"ONLY");
505 // ==========================================================
507 // ==========================================================
510 // auxilary structures
514 gMC->Gsvolu("TPWI","TUBE",idtmed[24],dm,0); // "air"
516 // ----------------------------------------------------------
517 // Large wheel -> positioned in the TPC
518 // ----------------------------------------------------------
521 z0 = 263.5; // TPC length - 1/2 spoke wheel width
527 gMC->Gsvolu("TPWL", "TUBE", idtmed[0], dm, 3);
533 gMC->Gsposp("TPWI",1,"TPWL",0.,0.,0.,0,"ONLY",dm,3);
535 gMC->Gspos("TPWL", 1, "TPC ", 0, 0, z0, 0, "ONLY");
536 gMC->Gspos("TPWL", 2, "TPC ", 0, 0, -z0, 0, "ONLY");
539 // Outer vessel + CO2 HV degrader
546 gMC->Gsvolu("TPCO","TUBE",idtmed[12],dm,3);
551 gMC->Gsvolu("TPOV","TUBE",idtmed[10],dm,3);
553 gMC->Gspos("TPOV",1,"TPCO",0.,0.,0.,0,"ONLY");
558 gMC->Gspos("TPCO",1,"TPC ",0.,0.,0.,0,"ONLY");
561 //----------------------------------------------------------
562 // Small wheel -> positioned in "side gas
563 //----------------------------------------------------------
569 gMC->Gsvolu("TPWS", "TUBE", idtmed[0], dm, 3);
575 gMC->Gsvolu("TPW1", "TUBE", idtmed[2], dm, 3);
577 gMC->Gspos("TPW1", 1, "TPWS", 0., 0., 0., 0, "ONLY");
579 z0 = 1.; // spoke wheel is shifted w.r.t. center of the "side gas"
581 gMC->Gspos("TPWS", 1, "TPSG", 0, 0, z0, 0, "ONLY");
590 gMC->Gsvolu("TPS1","TUBE",idtmed[0],dm,3);
594 gMC->Gsvolu("TPS2","TUBE",idtmed[24],dm,3);
596 gMC->Gspos("TPS2",1,"TPS1",0.,0.,0.,0,"ONLY");
600 gMC->Gspos("TPS1",1,"TPC ",0.,0.,z0,0,"ONLY");
601 gMC->Gspos("TPS1",2,"TPC ",0.,0.,-z0,0,"ONLY");
609 gMC->Gsvolu("TPG2","TUBE",idtmed[8],dm,3);
613 gMC->Gspos("TPG2",1,"TPC ",0.,0.,z0,0,"ONLY");
614 gMC->Gspos("TPG2",2,"TPC ",0.,0.,-z0,0,"ONLY");
617 //---------------------------------------------------------
618 // central wheel 6 (radial direction) x 4 (along z) cm2
619 //---------------------------------------------------------
625 gMC->Gsvolu("TPWC","TUBE",idtmed[0],dm,3);
631 gMC->Gsposp("TPWI",2,"TPWC",0.,0.,0.,0,"ONLY",dm,3);
633 z0 = z_side - 1.9 - 2.;
635 gMC->Gspos("TPWC",1,"TPSG",0.,0.,z0,0,"ONLY");
639 gMC->Gsvolu("TPSE","BOX ",idtmed[24],dm,0); // "empty" part of the spoke
642 //---------------------------------------------------------
643 // inner spokes (nSectorInner)
644 //---------------------------------------------------------
646 dm[0] = 0.5*(139.9-82.1);
650 Float_t x1 = dm[0]+82.;
652 gMC->Gsvolu("TPSI","BOX",idtmed[0],dm,3);
657 gMC->Gsposp("TPSE",1,"TPSI",0.,0.,0.,0,"ONLY",dm,3);
659 for(ns=0;ns<nInnerSector;ns++){
661 phi1 = 0.5*InnerOpenAngle + ns*InnerOpenAngle + InnerAngleShift;
665 phi1 = (Float_t)TMath::Nint(phi1);
666 if(phi1>360.) phi1 -= 360.;
669 if(phi2>360.) phi2 -= 360.;
674 alpha = phi1 * kDegrad;
675 x = x1 * TMath::Cos(alpha);
676 y = x1 * TMath::Sin(alpha);
678 AliMatrix(idrotm[nRotMat],theta1,phi1,theta2,phi2,theta3,phi3);
680 gMC->Gspos("TPSI",ns+1,"TPSG",x,y,z0,idrotm[nRotMat],"ONLY");
686 //-------------------------------------------------------------
687 // outer spokes (nSectorOuter)
688 //-------------------------------------------------------------
690 dm[0] = 0.5*(257.9-146.1);
696 gMC->Gsvolu("TPSO","BOX ",idtmed[0],dm,3);
701 gMC->Gsposp("TPSE",2,"TPSO",0.,0.,0.,0,"ONLY",dm,3);
703 for(ns=0;ns<nOuterSector;ns++){
705 phi1 = 0.5*OuterOpenAngle + ns*OuterOpenAngle + OuterAngleShift;
709 phi1 = (Float_t)TMath::Nint(phi1);
710 if(phi1>360.) phi1 -= 360.;
713 if(phi2>360.) phi2 -= 360.;
718 alpha = phi1 * kDegrad;
719 x = x1 * TMath::Cos(alpha);
720 y = x1 * TMath::Sin(alpha);
722 AliMatrix(idrotm[nRotMat],theta1,phi1,theta2,phi2,theta3,phi3);
724 gMC->Gspos("TPSO",ns+1,"TPSG",x,y,z0,idrotm[nRotMat],"ONLY");
732 // --------------------------------------------------------
733 // put the readout chambers into the TPC
734 // --------------------------------------------------------
743 AliMatrix(idrotm[nRotMat], theta1, phi1, theta2, phi2, theta3, phi3);
747 gMC->Gspos("TPSG", 1, "TPC ", 0, 0, z0, 0, "ONLY");
748 gMC->Gspos("TPSG", 2, "TPC ", 0, 0, -z0, idrotm[nRotMat], "ONLY");
750 gMC->Gspos("TPC ", 1, "ALIC", 0, 0, 0, 0, "ONLY");
752 //----------------------------------------------------
753 // Inner vessel and HV degrader
754 //----------------------------------------------------
776 gMC->Gsvolu("TPVD", "PCON", idtmed[12], dm, 15); // CO2
793 gMC->Gsvolu("TIVC","PCON",idtmed[11],dm,9); // C-fibre
795 gMC->Gspos("TIVC",1,"TPVD",0.,0.,0.,0,"ONLY");
796 gMC->Gspos("TIVC",2,"TPVD",0.,0.,0.,idrotm[nRotMat],"ONLY");
804 gMC->Gsvolu("TIVB","TUBE",idtmed[9],dm,3);
806 gMC->Gspos("TIVB",1,"TPVD",0.,0.,0.,0,"ONLY");
808 gMC->Gspos("TPVD",1,"ALIC",0.,0.,0.,0,"ONLY");
814 // ---------------------------------------------------
816 // ---------------------------------------------------
817 gMC->Gsord("TGAS", 6);
818 gMC->Gsord("TPSG", 6);
819 gMC->Gsord("TSGA", 3);
820 gMC->Gsord("TLGA", 4);
825 //_____________________________________________________________________________
826 void AliTPCv1::DrawDetector()
829 // Draw a shaded view of the Time Projection Chamber version 1
832 // Set everything unseen
833 gMC->Gsatt("*", "seen", -1);
835 // Set ALIC mother transparent
836 gMC->Gsatt("ALIC","SEEN",0);
838 // Set the volumes visible
839 gMC->Gsatt("TPC","SEEN",0);
840 gMC->Gsatt("TGAS","SEEN",0);
841 gMC->Gsatt("TPSG","SEEN",0);
842 gMC->Gsatt("TPHV","SEEN",1);
843 gMC->Gsatt("TPMH","SEEN",1);
844 gMC->Gsatt("TPEC","SEEN",0);
845 gMC->Gsatt("TRCS","SEEN",1);
846 gMC->Gsatt("TRCL","SEEN",1);
847 gMC->Gsatt("TPWL","SEEN",1);
848 gMC->Gsatt("TPWI","SEEN",1);
849 gMC->Gsatt("TPWS","SEEN",1);
850 gMC->Gsatt("TPW1","SEEN",1);
851 gMC->Gsatt("TPS1","SEEN",1);
852 gMC->Gsatt("TPS2","SEEN",1);
853 gMC->Gsatt("TPG1","SEEN",1);
854 gMC->Gsatt("TPG2","SEEN",1);
855 gMC->Gsatt("TPWC","SEEN",1);
856 gMC->Gsatt("TPSI","SEEN",1);
857 gMC->Gsatt("TPSO","SEEN",1);
858 gMC->Gsatt("TPCO","SEEN",1);
859 gMC->Gsatt("TPOV","SEEN",1);
860 gMC->Gsatt("TPVD","SEEN",1);
862 gMC->Gdopt("hide", "on");
863 gMC->Gdopt("shad", "on");
864 gMC->Gsatt("*", "fill", 7);
865 gMC->SetClipBox(".");
866 gMC->SetClipBox("*", 0, 1000, -1000, 1000, -1000, 1000);
868 gMC->Gdraw("alic", 40, 30, 0, 12, 9.5, .025, .025);
869 gMC->Gdhead(1111, "Time Projection Chamber");
870 gMC->Gdman(18, 4, "MAN");
871 gMC->Gdopt("hide","off");
874 //_____________________________________________________________________________
875 void AliTPCv1::CreateMaterials()
878 // Define materials for Time Projection Chamber
880 AliTPC::CreateMaterials();
883 //_____________________________________________________________________________
884 void AliTPCv1::Init()
887 // Initialises TPC detector after it has been created
890 fIdSens1=gMC->VolId("TLST"); // L-sector
891 fIdSens2=gMC->VolId("TSST"); // S-sector
893 printf("TPC version 1 initialized\n");
896 //_____________________________________________________________________________
897 void AliTPCv1::StepManager()
900 // Called at every step in the Time Projection Chamber
906 TClonesArray &lhits = *fHits;
910 if(gMC->TrackCharge() && gMC->IsTrackEntering()) {
912 // Only entering charged tracks
914 if((id=gMC->CurrentVolID(copy))==fIdSens1) {
918 vol[1]=copy-1; // row
919 id=gMC->CurrentVolOffID(1,copy);
920 vol[0]=copy+fTPCParam->GetNInnerSector()-1; // sector
922 //I.Belikov's modification
924 gMC->TrackMomentum(p);
928 hits[3]=0.; // this hit has no energy loss
929 new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
931 gMC->TrackPosition(p);
935 hits[3]=0.; // this hit has no energy loss
936 new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
938 //end of I.Belikov's modification
939 } else if(id==fIdSens2) {
943 vol[1]=copy-1; // row
944 id=gMC->CurrentVolOffID(1,copy); // sector
947 //I.Belikov's modification
949 gMC->TrackMomentum(p);
953 hits[3]=0.; // this hit has no energy loss
954 new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
956 gMC->TrackPosition(p);
960 hits[3]=0.; // this hit has no energy loss
961 new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
963 //end of I.Belikov's modification
967 gMC->TrackPosition(p);
968 for(i=0;i<3;++i) hits[i]=p[i];
969 hits[3]=1; //I'd like to have something positive here (I.Belikov)
970 new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);