| [807] | 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 | // $Id: MyMollerBhabhaModel.cc,v 1.1 2007/10/15 16:20:23 maire Exp $
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| [1337] | 27 | // GEANT4 tag $Name: geant4-09-04-beta-01 $
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| [807] | 28 | //
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| 29 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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| 30 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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| 31 |
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| 32 | #include "MyMollerBhabhaModel.hh"
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| 33 |
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| 34 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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| 35 |
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| 36 | using namespace std;
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| 37 |
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| 38 | MyMollerBhabhaModel::MyMollerBhabhaModel(const G4ParticleDefinition* p,
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| 39 | const G4String& nam)
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| 40 | : G4MollerBhabhaModel(p,nam)
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| 41 | {}
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| 42 |
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| 43 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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| 44 |
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| 45 | MyMollerBhabhaModel::~MyMollerBhabhaModel()
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| 46 | {}
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| 47 |
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| 48 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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| 49 |
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| 50 | G4double MyMollerBhabhaModel::ComputeDEDXPerVolume(
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| 51 | const G4Material* material,
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| 52 | const G4ParticleDefinition* p,
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| 53 | G4double kineticEnergy,
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| 54 | G4double cutEnergy)
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| 55 | {
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| 56 | if(!particle) SetParticle(p);
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| 57 | // calculate the dE/dx due to the ionization by Seltzer-Berger formula
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| 58 |
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| 59 | G4double electronDensity = material->GetElectronDensity();
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| 60 | G4double Zeff = electronDensity/material->GetTotNbOfAtomsPerVolume();
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| 61 | G4double th = 0.25*sqrt(Zeff)*keV;
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| 62 | G4double tkin = kineticEnergy;
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| 63 | G4bool lowEnergy = false;
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| 64 | if (kineticEnergy < th) {
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| 65 | tkin = th;
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| 66 | lowEnergy = true;
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| 67 | }
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| 68 | G4double tau = tkin/electron_mass_c2;
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| 69 | G4double gam = tau + 1.0;
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| 70 | G4double gamma2= gam*gam;
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| 71 | G4double beta2 = 1. - 1./gamma2;
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| 72 | //G4double bg2 = beta2*gamma2;
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| 73 |
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| 74 | G4double eexc = material->GetIonisation()->GetMeanExcitationEnergy();
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| 75 | eexc /= electron_mass_c2;
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| 76 | G4double eexc2 = eexc*eexc;
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| 77 |
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| 78 | G4double d = min(cutEnergy, MaxSecondaryEnergy(p, tkin))/electron_mass_c2;
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| 79 | G4double dedx;
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| 80 |
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| 81 | // electron
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| 82 | if (isElectron) {
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| 83 |
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| 84 | dedx = log(2.0*(tau + 2.0)/eexc2) - 1.0 - beta2
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| 85 | + log((tau-d)*d) + tau/(tau-d)
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| 86 | + (0.5*d*d + (2.0*tau + 1.)*log(1. - d/tau))/gamma2;
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| 87 |
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| 88 | //positron
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| 89 | } else {
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| 90 |
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| 91 | G4double d2 = d*d*0.5;
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| 92 | G4double d3 = d2*d/1.5;
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| 93 | G4double d4 = d3*d*3.75;
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| 94 | G4double y = 1.0/(1.0 + gam);
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| 95 | dedx = log(2.0*(tau + 2.0)/eexc2) + log(tau*d)
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| 96 | - beta2*(tau + 2.0*d - y*(3.0*d2
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| 97 | + y*(d - d3 + y*(d2 - tau*d3 + d4))))/tau;
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| 98 | }
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| 99 |
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| 100 | //do not apply density correction
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| 101 | //G4double cden = material->GetIonisation()->GetCdensity();
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| 102 | //G4double mden = material->GetIonisation()->GetMdensity();
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| 103 | //G4double aden = material->GetIonisation()->GetAdensity();
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| 104 | //G4double x0den = material->GetIonisation()->GetX0density();
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| 105 | //G4double x1den = material->GetIonisation()->GetX1density();
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| 106 | //G4double x = log(bg2)/twoln10;
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| 107 |
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| 108 | //if (x >= x0den) {
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| 109 | // dedx -= twoln10*x - cden;
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| 110 | // if (x < x1den) dedx -= aden*pow(x1den-x, mden);
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| 111 | //}
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| 112 |
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| 113 | // now you can compute the total ionization loss
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| 114 | dedx *= twopi_mc2_rcl2*electronDensity/beta2;
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| 115 | if (dedx < 0.0) dedx = 0.0;
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| 116 |
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| 117 | // lowenergy extrapolation
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| 118 |
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| 119 | if (lowEnergy) {
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| 120 |
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| 121 | if (kineticEnergy >= lowLimit) dedx *= sqrt(tkin/kineticEnergy);
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| 122 | else dedx *= sqrt(tkin*kineticEnergy)/lowLimit;
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| 123 |
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| 124 | }
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| 125 | return dedx;
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| 126 | }
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| 127 |
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| 128 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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