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 ////////////////////////////////////////////////////////////////////////////
20 // Transition Radiation Detector version 1 -- slow simulator //
22 ////////////////////////////////////////////////////////////////////////////
27 #include <TLorentzVector.h>
31 #include <TVirtualMC.h>
32 #include <TGeoManager.h>
33 #include <TGeoPhysicalNode.h>
40 #include "AliTRDgeometry.h"
41 #include "AliTRDhit.h"
42 #include "AliTRDsimTR.h"
47 //_____________________________________________________________________________
52 ,fTypeOfStepManager(0)
60 // Default constructor
65 //_____________________________________________________________________________
66 AliTRDv1::AliTRDv1(const char *name, const char *title)
70 ,fTypeOfStepManager(2)
78 // Standard constructor for Transition Radiation Detector version 1
81 SetBufferSize(128000);
85 //_____________________________________________________________________________
89 // AliTRDv1 destructor
109 //_____________________________________________________________________________
110 void AliTRDv1::AddAlignableVolumes() const
113 // Create entries for alignable volumes associating the symbolic volume
114 // name with the corresponding volume path. Needs to be syncronized with
115 // eventual changes in the geometry.
121 TString vpStr = "ALIC_1/B077_1/BSEGMO";
122 TString vpApp1 = "_1/BTRD";
123 TString vpApp2 = "_1";
124 TString vpApp3 = "/UTR1_1/UTS1_1/UTI1_1/UT";
126 TString snStr = "TRD/sm";
127 TString snApp1 = "/st";
128 TString snApp2 = "/pl";
132 // The symbolic names are: TRD/sm00
136 for (Int_t isect = 0; isect < AliTRDgeometry::Nsect(); isect++) {
145 symName += Form("%02d",isect);
147 gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data());
152 // The readout chambers
153 // The symbolic names are: TRD/sm00/st0/pl0
157 for (Int_t isect = 0; isect < AliTRDgeometry::Nsect(); isect++) {
158 for (Int_t icham = 0; icham < AliTRDgeometry::Ncham(); icham++) {
159 for (Int_t iplan = 0; iplan < AliTRDgeometry::Nplan(); iplan++) {
161 Int_t idet = AliTRDgeometry::GetDetectorSec(iplan,icham);
169 volPath += Form("%02d",idet);
173 symName += Form("%02d",isect);
179 TGeoPNEntry *alignableEntry =
180 gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data());
182 // Add the tracking to local matrix following the TPC example
184 if (alignableEntry) {
185 const char *path = alignableEntry->GetTitle();
186 if (!gGeoManager->cd(path)) {
187 AliFatal(Form("Volume path %s not valid!",path));
189 TGeoHMatrix *globMatrix = gGeoManager->GetCurrentMatrix();
190 Double_t sectorAngle = 20.0 * (isect % 18) + 10.0;
191 TGeoHMatrix *t2lMatrix = new TGeoHMatrix();
192 t2lMatrix->RotateZ(sectorAngle);
193 t2lMatrix->MultiplyLeft(&(globMatrix->Inverse()));
194 alignableEntry->SetMatrix(t2lMatrix);
197 AliError(Form("Alignable entry %s is not valid!",symName.Data()));
205 //_____________________________________________________________________________
206 void AliTRDv1::CreateGeometry()
209 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
210 // This version covers the full azimuth.
213 // Check that FRAME is there otherwise we have no place where to put the TRD
214 AliModule* frame = gAlice->GetModule("FRAME");
216 AliError("TRD needs FRAME to be present\n");
220 // Define the chambers
221 AliTRD::CreateGeometry();
225 //_____________________________________________________________________________
226 void AliTRDv1::CreateMaterials()
229 // Create materials for the Transition Radiation Detector version 1
232 AliTRD::CreateMaterials();
236 //_____________________________________________________________________________
237 void AliTRDv1::CreateTRhit(Int_t det)
240 // Creates an electron cluster from a TR photon.
241 // The photon is assumed to be created a the end of the radiator. The
242 // distance after which it deposits its energy takes into account the
243 // absorbtion of the entrance window and of the gas mixture in drift
248 const Float_t kWion = 23.53;
250 // Maximum number of TR photons per track
251 const Int_t kNTR = 50;
260 gMC->TrackMomentum(mom);
261 Float_t pTot = mom.Rho();
262 fTR->CreatePhotons(11,pTot,nTR,eTR);
264 AliFatal(Form("Boundary error: nTR = %d, kNTR = %d",nTR,kNTR));
267 // Loop through the TR photons
268 for (Int_t iTR = 0; iTR < nTR; iTR++) {
270 Float_t energyMeV = eTR[iTR] * 0.001;
271 Float_t energyeV = eTR[iTR] * 1000.0;
272 Float_t absLength = 0.0;
275 // Take the absorbtion in the entrance window into account
276 Double_t muMy = fTR->GetMuMy(energyMeV);
277 sigma = muMy * fFoilDensity;
279 absLength = gRandom->Exp(1.0/sigma);
280 if (absLength < AliTRDgeometry::MyThick()) {
288 // The absorbtion cross sections in the drift gas
289 // Gas-mixture (Xe/CO2)
290 Double_t muXe = fTR->GetMuXe(energyMeV);
291 Double_t muCO = fTR->GetMuCO(energyMeV);
292 sigma = (0.85 * muXe + 0.15 * muCO) * fGasDensity * fTR->GetTemp();
294 // The distance after which the energy of the TR photon
297 absLength = gRandom->Exp(1.0/sigma);
298 if (absLength > (AliTRDgeometry::DrThick()
299 + AliTRDgeometry::AmThick())) {
307 // The position of the absorbtion
309 gMC->TrackPosition(pos);
310 posHit[0] = pos[0] + mom[0] / pTot * absLength;
311 posHit[1] = pos[1] + mom[1] / pTot * absLength;
312 posHit[2] = pos[2] + mom[2] / pTot * absLength;
315 Int_t q = ((Int_t) (energyeV / kWion));
317 // Add the hit to the array. TR photon hits are marked
318 // by negative charge
319 AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
323 ,gMC->TrackTime()*1.0e06
330 //_____________________________________________________________________________
331 void AliTRDv1::Init()
334 // Initialise Transition Radiation Detector after geometry has been built.
339 AliDebug(1,"Slow simulator\n");
341 // Switch on TR simulation as default
343 AliInfo("TR simulation off");
346 fTR = new AliTRDsimTR();
349 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
350 const Float_t kPoti = 12.1;
351 // Maximum energy (50 keV);
352 const Float_t kEend = 50000.0;
353 // Ermilova distribution for the delta-ray spectrum
354 Float_t poti = TMath::Log(kPoti);
355 Float_t eEnd = TMath::Log(kEend);
357 // Ermilova distribution for the delta-ray spectrum
358 fDeltaE = new TF1("deltae" ,Ermilova ,poti,eEnd,0);
360 // Geant3 distribution for the delta-ray spectrum
361 fDeltaG = new TF1("deltag",IntSpecGeant,2.421257,28.536469,0);
363 AliDebug(1,"+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
367 //_____________________________________________________________________________
368 void AliTRDv1::StepManager()
371 // Slow simulator. Every charged track produces electron cluster as hits
372 // along its path across the drift volume.
375 switch (fTypeOfStepManager) {
377 StepManagerErmilova();
383 StepManagerFixedStep();
386 AliWarning("Not a valid Step Manager.");
391 //_____________________________________________________________________________
392 void AliTRDv1::SelectStepManager(Int_t t)
395 // Selects a step manager type:
398 // 2 - Fixed step size
401 fTypeOfStepManager = t;
402 AliInfo(Form("Step Manager type %d was selected",fTypeOfStepManager));
406 //_____________________________________________________________________________
407 void AliTRDv1::StepManagerGeant()
410 // Slow simulator. Every charged track produces electron cluster as hits
411 // along its path across the drift volume. The step size is set acording
412 // to Bethe-Bloch. The energy distribution of the delta electrons follows
413 // a spectrum taken from Geant3.
415 // Version by A. Bercuci
433 Double_t stepSize = 0;
435 Bool_t drRegion = kFALSE;
436 Bool_t amRegion = kFALSE;
443 TString cIdSensDr = "J";
444 TString cIdSensAm = "K";
445 Char_t cIdChamber[3];
453 const Int_t kNplan = AliTRDgeometry::Nplan();
454 const Int_t kNcham = AliTRDgeometry::Ncham();
455 const Int_t kNdetsec = kNplan * kNcham;
457 const Double_t kBig = 1.0e+12; // Infinitely big
458 const Float_t kWion = 23.53; // Ionization energy
459 const Float_t kPTotMaxEl = 0.002; // Maximum momentum for e+ e- g
461 // Minimum energy for the step size adjustment
462 const Float_t kEkinMinStep = 1.0e-5;
463 // energy threshold for production of delta electrons
464 const Float_t kECut = 1.0e4;
465 // Parameters entering the parametrized range for delta electrons
466 const Float_t kRa = 5.37e-4;
467 const Float_t kRb = 0.9815;
468 const Float_t kRc = 3.123e-3;
469 // Gas density -> To be made user adjustable !
470 // [0.85*0.00549+0.15*0.00186 (Xe-CO2 85-15)]
471 const Float_t kRho = 0.004945 ;
473 // Plateau value of the energy-loss for electron in xenon
474 // The averaged value (26/3/99)
475 const Float_t kPlateau = 1.55;
476 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
477 const Float_t kPrim = 19.34;
478 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
479 const Float_t kPoti = 12.1;
481 const Int_t kPdgElectron = 11;
483 // Set the maximum step size to a very large number for all
484 // neutral particles and those outside the driftvolume
485 gMC->SetMaxStep(kBig);
487 // Use only charged tracks
488 if (( gMC->TrackCharge() ) &&
489 (!gMC->IsTrackDisappeared())) {
491 // Inside a sensitive volume?
494 cIdCurrent = gMC->CurrentVolName();
495 if (cIdSensDr == cIdCurrent[1]) {
498 if (cIdSensAm == cIdCurrent[1]) {
501 if (drRegion || amRegion) {
503 // The hit coordinates and charge
504 gMC->TrackPosition(pos);
509 // The sector number (0 - 17), according to standard coordinate system
510 cIdPath = gGeoManager->GetPath();
511 cIdSector[0] = cIdPath[21];
512 cIdSector[1] = cIdPath[22];
513 sec = atoi(cIdSector);
515 // The plane and chamber number
516 cIdChamber[0] = cIdCurrent[2];
517 cIdChamber[1] = cIdCurrent[3];
518 Int_t idChamber = (atoi(cIdChamber) % kNdetsec);
519 cha = ((Int_t) idChamber / kNplan);
520 pla = ((Int_t) idChamber % kNplan);
522 // The detector number
523 det = fGeometry->GetDetector(pla,cha,sec);
525 // Special hits only in the drift region
527 (gMC->IsTrackEntering())) {
529 // Create a track reference at the entrance of each
530 // chamber that contains the momentum components of the particle
531 gMC->TrackMomentum(mom);
532 AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber());
534 // Create the hits from TR photons if electron/positron is
535 // entering the drift volume
537 (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) {
542 else if ((amRegion) &&
543 (gMC->IsTrackExiting())) {
545 // Create a track reference at the exit of each
546 // chamber that contains the momentum components of the particle
547 gMC->TrackMomentum(mom);
548 AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber());
552 // Calculate the energy of the delta-electrons
553 // modified by Alex Bercuci (A.Bercuci@gsi.de) on 26.01.06
554 // take into account correlation with the underlying GEANT tracking
556 // http://www-linux.gsi.de/~abercuci/Contributions/TRD/index.html
558 // determine the most significant process (last on the processes list)
559 // which caused this hit
560 gMC->StepProcesses(processes);
561 Int_t nofprocesses = processes.GetSize();
567 pid = processes[nofprocesses-1];
570 // Generate Edep according to GEANT parametrisation
571 eDelta = TMath::Exp(fDeltaG->GetRandom()) - kPoti;
572 eDelta = TMath::Max(eDelta,0.0);
573 Float_t prRange = 0.0;
574 Float_t range = gMC->TrackLength() - fTrackLength0;
575 // merge GEANT tracker information with locally cooked one
576 if (gAlice->GetMCApp()->GetCurrentTrackNumber() == fPrimaryTrackPid) {
578 if (eDelta >= kECut) {
579 prRange = kRa * eDelta * 0.001
580 * (1.0 - kRb / (1.0 + kRc * eDelta * 0.001)) / kRho;
581 if (prRange >= (3.7 - range)) {
587 if (eDelta < kECut) {
591 prRange = kRa * eDelta * 0.001
592 * (1.0 - kRb / (1.0 + kRc * eDelta * 0.001)) / kRho;
593 if (prRange >= ((AliTRDgeometry::DrThick()
594 + AliTRDgeometry::AmThick()) - range)) {
610 // Generate the electron cluster size
613 qTot = ((Int_t) (eDelta / kWion) + 1);
615 // Create a new dEdx hit
616 AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
620 ,gMC->TrackTime()*1.0e06
625 // Calculate the maximum step size for the next tracking step
626 // Produce only one hit if Ekin is below cutoff
627 aMass = gMC->TrackMass();
628 if ((gMC->Etot() - aMass) > kEkinMinStep) {
630 // The energy loss according to Bethe Bloch
631 iPdg = TMath::Abs(gMC->TrackPid());
632 if ((iPdg != kPdgElectron) ||
633 ((iPdg == kPdgElectron) &&
634 (pTot < kPTotMaxEl))) {
635 gMC->TrackMomentum(mom);
637 betaGamma = pTot / aMass;
638 pp = BetheBlochGeant(betaGamma);
639 // Take charge > 1 into account
640 charge = gMC->TrackCharge();
641 if (TMath::Abs(charge) > 1) {
642 pp = pp * charge*charge;
646 // Electrons above 20 Mev/c are at the plateau
647 pp = kPrim * kPlateau;
652 nsteps = gRandom->Poisson(pp);
654 stepSize = 1.0 / nsteps;
655 gMC->SetMaxStep(stepSize);
665 //_____________________________________________________________________________
666 void AliTRDv1::StepManagerErmilova()
669 // Slow simulator. Every charged track produces electron cluster as hits
670 // along its path across the drift volume. The step size is set acording
671 // to Bethe-Bloch. The energy distribution of the delta electrons follows
672 // a spectrum taken from Ermilova et al.
693 Bool_t drRegion = kFALSE;
694 Bool_t amRegion = kFALSE;
701 TString cIdSensDr = "J";
702 TString cIdSensAm = "K";
703 Char_t cIdChamber[3];
709 const Int_t kNplan = AliTRDgeometry::Nplan();
710 const Int_t kNcham = AliTRDgeometry::Ncham();
711 const Int_t kNdetsec = kNplan * kNcham;
713 const Double_t kBig = 1.0e+12; // Infinitely big
714 const Float_t kWion = 23.53; // Ionization energy
715 const Float_t kPTotMaxEl = 0.002; // Maximum momentum for e+ e- g
717 // Minimum energy for the step size adjustment
718 const Float_t kEkinMinStep = 1.0e-5;
720 // Plateau value of the energy-loss for electron in xenon
721 // The averaged value (26/3/99)
722 const Float_t kPlateau = 1.55;
723 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
724 const Float_t kPrim = 48.0;
725 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
726 const Float_t kPoti = 12.1;
728 const Int_t kPdgElectron = 11;
730 // Set the maximum step size to a very large number for all
731 // neutral particles and those outside the driftvolume
732 gMC->SetMaxStep(kBig);
734 // Use only charged tracks
735 if (( gMC->TrackCharge() ) &&
736 (!gMC->IsTrackDisappeared())) {
738 // Inside a sensitive volume?
741 cIdCurrent = gMC->CurrentVolName();
742 if (cIdSensDr == cIdCurrent[1]) {
745 if (cIdSensAm == cIdCurrent[1]) {
748 if (drRegion || amRegion) {
750 // The hit coordinates and charge
751 gMC->TrackPosition(pos);
756 // The sector number (0 - 17), according to standard coordinate system
757 cIdPath = gGeoManager->GetPath();
758 cIdSector[0] = cIdPath[21];
759 cIdSector[1] = cIdPath[22];
760 sec = atoi(cIdSector);
762 // The plane and chamber number
763 cIdChamber[0] = cIdCurrent[2];
764 cIdChamber[1] = cIdCurrent[3];
765 Int_t idChamber = (atoi(cIdChamber) % kNdetsec);
766 cha = ((Int_t) idChamber / kNplan);
767 pla = ((Int_t) idChamber % kNplan);
769 // The detector number
770 det = fGeometry->GetDetector(pla,cha,sec);
772 // Special hits only in the drift region
774 (gMC->IsTrackEntering())) {
776 // Create a track reference at the entrance of each
777 // chamber that contains the momentum components of the particle
778 gMC->TrackMomentum(mom);
779 AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber());
781 // Create the hits from TR photons if electron/positron is
782 // entering the drift volume
784 (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) {
789 else if ((amRegion) &&
790 (gMC->IsTrackExiting())) {
792 // Create a track reference at the exit of each
793 // chamber that contains the momentum components of the particle
794 gMC->TrackMomentum(mom);
795 AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber());
799 // Calculate the energy of the delta-electrons
800 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
801 eDelta = TMath::Max(eDelta,0.0);
803 // Generate the electron cluster size
806 qTot = ((Int_t) (eDelta / kWion) + 1);
808 // Create a new dEdx hit
810 AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
814 ,gMC->TrackTime()*1.0e06
818 AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
822 ,gMC->TrackTime()*1.0e06
828 // Calculate the maximum step size for the next tracking step
829 // Produce only one hit if Ekin is below cutoff
830 aMass = gMC->TrackMass();
831 if ((gMC->Etot() - aMass) > kEkinMinStep) {
833 // The energy loss according to Bethe Bloch
834 iPdg = TMath::Abs(gMC->TrackPid());
835 if ((iPdg != kPdgElectron) ||
836 ((iPdg == kPdgElectron) &&
837 (pTot < kPTotMaxEl))) {
838 gMC->TrackMomentum(mom);
840 betaGamma = pTot / aMass;
841 pp = kPrim * BetheBloch(betaGamma);
842 // Take charge > 1 into account
843 charge = gMC->TrackCharge();
844 if (TMath::Abs(charge) > 1) {
845 pp = pp * charge*charge;
849 // Electrons above 20 Mev/c are at the plateau
850 pp = kPrim * kPlateau;
855 gMC->GetRandom()->RndmArray(1,random);
857 while ((random[0] == 1.0) ||
859 stepSize = - TMath::Log(random[0]) / pp;
860 gMC->SetMaxStep(stepSize);
871 //_____________________________________________________________________________
872 void AliTRDv1::StepManagerFixedStep()
875 // Slow simulator. Every charged track produces electron cluster as hits
876 // along its path across the drift volume. The step size is fixed in
877 // this version of the step manager.
881 const Int_t kPdgElectron = 11;
892 Bool_t drRegion = kFALSE;
893 Bool_t amRegion = kFALSE;
900 TString cIdSensDr = "J";
901 TString cIdSensAm = "K";
902 Char_t cIdChamber[3];
908 const Int_t kNplan = AliTRDgeometry::Nplan();
909 const Int_t kNcham = AliTRDgeometry::Ncham();
910 const Int_t kNdetsec = kNplan * kNcham;
912 const Double_t kBig = 1.0e+12;
914 const Float_t kWion = 23.53; // Ionization energy
915 const Float_t kEkinMinStep = 1.0e-5; // Minimum energy for the step size adjustment
917 // Set the maximum step size to a very large number for all
918 // neutral particles and those outside the driftvolume
919 gMC->SetMaxStep(kBig);
921 // If not charged track or already stopped or disappeared, just return.
922 if ((!gMC->TrackCharge()) ||
923 gMC->IsTrackDisappeared()) {
927 // Inside a sensitive volume?
928 cIdCurrent = gMC->CurrentVolName();
930 if (cIdSensDr == cIdCurrent[1]) {
933 if (cIdSensAm == cIdCurrent[1]) {
942 // The hit coordinates and charge
943 gMC->TrackPosition(pos);
948 // The sector number (0 - 17), according to standard coordinate system
949 cIdPath = gGeoManager->GetPath();
950 cIdSector[0] = cIdPath[21];
951 cIdSector[1] = cIdPath[22];
952 sec = atoi(cIdSector);
954 // The plane and chamber number
955 cIdChamber[0] = cIdCurrent[2];
956 cIdChamber[1] = cIdCurrent[3];
957 Int_t idChamber = (atoi(cIdChamber) % kNdetsec);
958 cha = ((Int_t) idChamber / kNplan);
959 pla = ((Int_t) idChamber % kNplan);
961 // The detector number
962 det = fGeometry->GetDetector(pla,cha,sec);
964 // 0: InFlight 1:Entering 2:Exiting
967 // Special hits only in the drift region
969 (gMC->IsTrackEntering())) {
971 // Create a track reference at the entrance of each
972 // chamber that contains the momentum components of the particle
973 gMC->TrackMomentum(mom);
974 AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber());
977 // Create the hits from TR photons if electron/positron is
978 // entering the drift volume
980 (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) {
985 else if ((amRegion) &&
986 (gMC->IsTrackExiting())) {
988 // Create a track reference at the exit of each
989 // chamber that contains the momentum components of the particle
990 gMC->TrackMomentum(mom);
991 AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber());
996 // Calculate the charge according to GEANT Edep
997 // Create a new dEdx hit
998 eDep = TMath::Max(gMC->Edep(),0.0) * 1.0e+09;
999 qTot = (Int_t) (eDep / kWion);
1002 AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
1006 ,gMC->TrackTime()*1.0e06
1010 // Set Maximum Step Size
1011 // Produce only one hit if Ekin is below cutoff
1012 if ((gMC->Etot() - gMC->TrackMass()) < kEkinMinStep) {
1015 gMC->SetMaxStep(fStepSize);
1019 //_____________________________________________________________________________
1020 Double_t AliTRDv1::BetheBloch(Double_t bg)
1023 // Parametrization of the Bethe-Bloch-curve
1024 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
1027 // This parameters have been adjusted to averaged values from GEANT
1028 const Double_t kP1 = 7.17960e-02;
1029 const Double_t kP2 = 8.54196;
1030 const Double_t kP3 = 1.38065e-06;
1031 const Double_t kP4 = 5.30972;
1032 const Double_t kP5 = 2.83798;
1034 // Lower cutoff of the Bethe-Bloch-curve to limit step sizes
1035 const Double_t kBgMin = 0.8;
1036 const Double_t kBBMax = 6.83298;
1039 Double_t yy = bg / TMath::Sqrt(1.0 + bg*bg);
1040 Double_t aa = TMath::Power(yy,kP4);
1041 Double_t bb = TMath::Power((1.0/bg),kP5);
1042 bb = TMath::Log(kP3 + bb);
1043 return ((kP2 - aa - bb) * kP1 / aa);
1051 //_____________________________________________________________________________
1052 Double_t AliTRDv1::BetheBlochGeant(Double_t bg)
1055 // Return dN/dx (number of primary collisions per centimeter)
1056 // for given beta*gamma factor.
1058 // Implemented by K.Oyama according to GEANT 3 parametrization shown in
1059 // A.Andronic's webpage: http://www-alice.gsi.de/trd/papers/dedx/dedx.html
1060 // This must be used as a set with IntSpecGeant.
1065 Double_t arrG[20] = { 1.100000, 1.200000, 1.300000, 1.500000
1066 , 1.800000, 2.000000, 2.500000, 3.000000
1067 , 4.000000, 7.000000, 10.000000, 20.000000
1068 , 40.000000, 70.000000, 100.000000, 300.000000
1069 , 600.000000, 1000.000000, 3000.000000, 10000.000000 };
1071 Double_t arrNC[20] = { 75.009056, 45.508083, 35.299252, 27.116327
1072 , 22.734999, 21.411915, 19.934095, 19.449375
1073 , 19.344431, 20.185553, 21.027925, 22.912676
1074 , 24.933352, 26.504053, 27.387468, 29.566597
1075 , 30.353779, 30.787134, 31.129285, 31.157350 };
1077 // Betagamma to gamma
1078 Double_t g = TMath::Sqrt(1.0 + bg*bg);
1080 // Find the index just before the point we need.
1081 for (i = 0; i < 18; i++) {
1082 if ((arrG[i] < g) &&
1088 // Simple interpolation.
1089 Double_t pp = ((arrNC[i+1] - arrNC[i]) / (arrG[i+1] - arrG[i]))
1090 * (g - arrG[i]) + arrNC[i];
1096 //_____________________________________________________________________________
1097 Double_t Ermilova(Double_t *x, Double_t *)
1100 // Calculates the delta-ray energy distribution according to Ermilova.
1101 // Logarithmic scale !
1111 const Int_t kNv = 31;
1113 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
1114 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
1115 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
1116 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
1117 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
1118 , 9.4727, 9.9035, 10.3735, 10.5966, 10.8198
1121 Float_t vye[kNv] = { 80.0, 31.0, 23.3, 21.1, 21.0
1122 , 20.9, 20.8, 20.0, 16.0, 11.0
1123 , 8.0, 6.0, 5.2, 4.6, 4.0
1124 , 3.5, 3.0, 1.4, 0.67, 0.44
1125 , 0.3, 0.18, 0.12, 0.08, 0.056
1126 , 0.04, 0.023, 0.015, 0.011, 0.01
1131 // Find the position
1136 dpos = energy - vxe[pos2++];
1145 // Differentiate between the sampling points
1146 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);
1152 //_____________________________________________________________________________
1153 Double_t IntSpecGeant(Double_t *x, Double_t *)
1156 // Integrated spectrum from Geant3
1159 const Int_t npts = 83;
1160 Double_t arre[npts] = { 2.421257, 2.483278, 2.534301, 2.592230
1161 , 2.672067, 2.813299, 3.015059, 3.216819
1162 , 3.418579, 3.620338, 3.868209, 3.920198
1163 , 3.978284, 4.063923, 4.186264, 4.308605
1164 , 4.430946, 4.553288, 4.724261, 4.837736
1165 , 4.999842, 5.161949, 5.324056, 5.486163
1166 , 5.679688, 5.752998, 5.857728, 5.962457
1167 , 6.067185, 6.171914, 6.315653, 6.393674
1168 , 6.471694, 6.539689, 6.597658, 6.655627
1169 , 6.710957, 6.763648, 6.816338, 6.876198
1170 , 6.943227, 7.010257, 7.106285, 7.252151
1171 , 7.460531, 7.668911, 7.877290, 8.085670
1172 , 8.302979, 8.353585, 8.413120, 8.483500
1173 , 8.541030, 8.592857, 8.668865, 8.820485
1174 , 9.037086, 9.253686, 9.470286, 9.686887
1175 , 9.930838, 9.994655, 10.085822, 10.176990
1176 , 10.268158, 10.359325, 10.503614, 10.627565
1177 , 10.804637, 10.981709, 11.158781, 11.335854
1178 , 11.593397, 11.781165, 12.049404, 12.317644
1179 , 12.585884, 12.854123, 14.278421, 16.975889
1180 , 20.829416, 24.682943, 28.536469 };
1182 Double_t arrdnde[npts] = { 10.960000, 10.960000, 10.359500, 9.811340
1183 , 9.1601500, 8.206670, 6.919630, 5.655430
1184 , 4.6221300, 3.777610, 3.019560, 2.591950
1185 , 2.5414600, 2.712920, 3.327460, 4.928240
1186 , 7.6185300, 10.966700, 12.225800, 8.094750
1187 , 3.3586900, 1.553650, 1.209600, 1.263840
1188 , 1.3241100, 1.312140, 1.255130, 1.165770
1189 , 1.0594500, 0.945450, 0.813231, 0.699837
1190 , 0.6235580, 2.260990, 2.968350, 2.240320
1191 , 1.7988300, 1.553300, 1.432070, 1.535520
1192 , 1.4429900, 1.247990, 1.050750, 0.829549
1193 , 0.5900280, 0.395897, 0.268741, 0.185320
1194 , 0.1292120, 0.103545, 0.0949525, 0.101535
1195 , 0.1276380, 0.134216, 0.123816, 0.104557
1196 , 0.0751843, 0.0521745, 0.0373546, 0.0275391
1197 , 0.0204713, 0.0169234, 0.0154552, 0.0139194
1198 , 0.0125592, 0.0113638, 0.0107354, 0.0102137
1199 , 0.00845984, 0.00683338, 0.00556836, 0.00456874
1200 , 0.0036227, 0.00285991, 0.00226664, 0.00172234
1201 , 0.00131226, 0.00100284, 0.000465492, 7.26607e-05
1202 , 3.63304e-06, 0.0000000, 0.0000000 };
1205 Double_t energy = x[0];
1207 for (i = 0; i < npts; i++) {
1208 if (energy < arre[i]) {
1214 AliErrorGeneral("AliTRDv1::IntSpecGeant","Given energy value is too small or zero");