| 1 | //
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| 2 | // ********************************************************************
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| 3 | // * License and Disclaimer *
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| 4 | // * *
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of *
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and *
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| 7 | // * conditions of the Geant4 Software License, included in the file *
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These *
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| 9 | // * include a list of copyright holders. *
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| 10 | // * *
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| 11 | // * Neither the authors of this software system, nor their employing *
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| 12 | // * institutes,nor the agencies providing financial support for this *
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| 13 | // * work make any representation or warranty, express or implied, *
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| 14 | // * regarding this software system or assume any liability for its *
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| 15 | // * use. Please see the license in the file LICENSE and URL above *
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| 16 | // * for the full disclaimer and the limitation of liability. *
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| 17 | // * *
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| 18 | // * This code implementation is the result of the scientific and *
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| 19 | // * technical work of the GEANT4 collaboration. *
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| 20 | // * By using, copying, modifying or distributing the software (or *
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| 21 | // * any work based on the software) you agree to acknowledge its *
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| 22 | // * use in resulting scientific publications, and indicate your *
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| 23 | // * acceptance of all terms of the Geant4 Software license. *
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| 24 | // ********************************************************************
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| 25 | //
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| 26 | //
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| 27 | // $Id: G4RToEConvForPositron.cc,v 1.7 2009/09/11 15:21:39 kurasige Exp $
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| 28 | // GEANT4 tag $Name: geant4-09-04-beta-01 $
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| 29 | //
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| 30 | //
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| 31 | // --------------------------------------------------------------
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| 32 | // GEANT 4 class implementation file/ History:
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| 33 | // 5 Oct. 2002, H.Kuirashige : Structure created based on object model
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| 34 | // --------------------------------------------------------------
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| 35 |
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| 36 | #include "G4RToEConvForPositron.hh"
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| 37 | #include "G4ParticleDefinition.hh"
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| 38 | #include "G4ParticleTable.hh"
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| 39 | #include "G4Material.hh"
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| 40 | #include "G4PhysicsLogVector.hh"
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| 41 |
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| 42 | #include "G4ios.hh"
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| 43 |
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| 44 | G4RToEConvForPositron::G4RToEConvForPositron() : G4VRangeToEnergyConverter()
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| 45 | {
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| 46 | theParticle = G4ParticleTable::GetParticleTable()->FindParticle("e+");
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| 47 | if (theParticle ==0) {
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| 48 | #ifdef G4VERBOSE
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| 49 | if (GetVerboseLevel()>0) {
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| 50 | G4cout << " G4RToEConvForPositron::G4RToEConvForPositron() ";
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| 51 | G4cout << " Positron is not defined !!" << G4endl;
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| 52 | }
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| 53 | #endif
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| 54 | }
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| 55 | }
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| 56 |
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| 57 | G4RToEConvForPositron::~G4RToEConvForPositron()
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| 58 | {
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| 59 | }
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| 60 |
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| 61 |
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| 62 |
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| 63 |
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| 64 | // **********************************************************************
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| 65 | // ************************* ComputeLoss ********************************
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| 66 | // **********************************************************************
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| 67 | G4double G4RToEConvForPositron::ComputeLoss(G4double AtomicNumber,
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| 68 | G4double KineticEnergy) const
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| 69 | {
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| 70 | static G4double Z;
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| 71 | static G4double taul, ionpot, ionpotlog;
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| 72 | const G4double cbr1=0.02, cbr2=-5.7e-5, cbr3=1., cbr4=0.072;
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| 73 | const G4double Tlow=10.*keV, Thigh=1.*GeV;
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| 74 | static G4double bremfactor = 0.1 ;
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| 75 |
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| 76 | G4double Mass = theParticle->GetPDGMass();
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| 77 | // calculate dE/dx for electrons
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| 78 | if( std::fabs(AtomicNumber-Z)>0.1 ) {
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| 79 | Z = AtomicNumber;
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| 80 | taul = Tlow/Mass;
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| 81 | ionpot = 1.6e-5*MeV*std::exp(0.9*std::log(Z))/Mass;
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| 82 | ionpotlog = std::log(ionpot);
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| 83 | }
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| 84 |
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| 85 | G4double tau = KineticEnergy/Mass;
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| 86 | G4double dEdx;
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| 87 |
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| 88 | if(tau<taul)
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| 89 | {
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| 90 | G4double t1 = taul+1.;
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| 91 | G4double t2 = taul+2.;
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| 92 | G4double tsq = taul*taul;
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| 93 | G4double beta2 = taul*t2/(t1*t1);
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| 94 | G4double f = 2.*std::log(taul)
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| 95 | -(6.*taul+1.5*tsq-taul*(1.-tsq/3.)/t2-tsq*(0.5-tsq/12.)/
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| 96 | (t2*t2))/(t1*t1);
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| 97 | dEdx = (std::log(2.*taul+4.)-2.*ionpotlog+f)/beta2;
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| 98 | dEdx = twopi_mc2_rcl2*Z*dEdx;
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| 99 | G4double clow = dEdx*std::sqrt(taul);
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| 100 | dEdx = clow/std::sqrt(KineticEnergy/Mass);
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| 101 |
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| 102 | } else {
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| 103 | G4double t1 = tau+1.;
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| 104 | G4double t2 = tau+2.;
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| 105 | G4double tsq = tau*tau;
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| 106 | G4double beta2 = tau*t2/(t1*t1);
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| 107 | G4double f = 2.*std::log(tau)
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| 108 | - (6.*tau+1.5*tsq-tau*(1.-tsq/3.)/t2-tsq*(0.5-tsq/12.)/
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| 109 | (t2*t2))/(t1*t1);
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| 110 | dEdx = (std::log(2.*tau+4.)-2.*ionpotlog+f)/beta2;
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| 111 | dEdx = twopi_mc2_rcl2*Z*dEdx;
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| 112 |
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| 113 | // loss from bremsstrahlung follows
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| 114 | G4double cbrem = (cbr1+cbr2*Z)
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| 115 | *(cbr3+cbr4*std::log(KineticEnergy/Thigh));
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| 116 | cbrem = Z*(Z+1.)*cbrem*tau/beta2;
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| 117 | cbrem *= bremfactor ;
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| 118 | dEdx += twopi_mc2_rcl2*cbrem;
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| 119 | }
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| 120 | return dEdx;
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| 121 | }
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| 122 |
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| 123 |
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