00001 // 00002 // ******************************************************************** 00003 // * License and Disclaimer * 00004 // * * 00005 // * The Geant4 software is copyright of the Copyright Holders of * 00006 // * the Geant4 Collaboration. It is provided under the terms and * 00007 // * conditions of the Geant4 Software License, included in the file * 00008 // * LICENSE and available at http://cern.ch/geant4/license . These * 00009 // * include a list of copyright holders. * 00010 // * * 00011 // * Neither the authors of this software system, nor their employing * 00012 // * institutes,nor the agencies providing financial support for this * 00013 // * work make any representation or warranty, express or implied, * 00014 // * regarding this software system or assume any liability for its * 00015 // * use. Please see the license in the file LICENSE and URL above * 00016 // * for the full disclaimer and the limitation of liability. * 00017 // * * 00018 // * This code implementation is the result of the scientific and * 00019 // * technical work of the GEANT4 collaboration. * 00020 // * By using, copying, modifying or distributing the software (or * 00021 // * any work based on the software) you agree to acknowledge its * 00022 // * use in resulting scientific publications, and indicate your * 00023 // * acceptance of all terms of the Geant4 Software license. * 00024 // ******************************************************************** 00025 // 00026 // 00027 // $Id$ 00028 // 00029 // 00030 // -------------------------------------------------------------- 00031 // GEANT 4 class implementation file/ History: 00032 // 5 Oct. 2002, H.Kuirashige : Structure created based on object model 00033 // -------------------------------------------------------------- 00034 00035 #include "G4RToEConvForElectron.hh" 00036 #include "G4ParticleDefinition.hh" 00037 #include "G4ParticleTable.hh" 00038 #include "G4Material.hh" 00039 #include "G4PhysicsLogVector.hh" 00040 00041 #include "G4ios.hh" 00042 #include "G4PhysicalConstants.hh" 00043 #include "G4SystemOfUnits.hh" 00044 00045 G4RToEConvForElectron::G4RToEConvForElectron() : G4VRangeToEnergyConverter() 00046 { 00047 theParticle = G4ParticleTable::GetParticleTable()->FindParticle("e-"); 00048 if (theParticle ==0) { 00049 #ifdef G4VERBOSE 00050 if (GetVerboseLevel()>0) { 00051 G4cout << " G4RToEConvForElectron::G4RToEConvForElectron() "; 00052 G4cout << " Electron is not defined !!" << G4endl; 00053 } 00054 #endif 00055 } 00056 } 00057 00058 G4RToEConvForElectron::~G4RToEConvForElectron() 00059 { 00060 } 00061 00062 00063 // ********************************************************************** 00064 // ************************* ComputeLoss ******************************** 00065 // ********************************************************************** 00066 G4double G4RToEConvForElectron::ComputeLoss(G4double AtomicNumber, 00067 G4double KineticEnergy) const 00068 { 00069 static G4double Z; 00070 static G4double taul, ionpot, ionpotlog; 00071 const G4double cbr1=0.02, cbr2=-5.7e-5, cbr3=1., cbr4=0.072; 00072 const G4double Tlow=10.*keV, Thigh=1.*GeV; 00073 static G4double bremfactor= 0.1 ; 00074 00075 static G4double Mass= theParticle->GetPDGMass(); 00076 00077 // calculate dE/dx for electrons 00078 if( std::fabs(AtomicNumber-Z)>0.1 ) { 00079 Z = AtomicNumber; 00080 taul = Tlow/Mass; 00081 ionpot = 1.6e-5*MeV*std::exp(0.9*std::log(Z))/Mass; 00082 ionpotlog = std::log(ionpot); 00083 } 00084 00085 00086 G4double tau = KineticEnergy/Mass; 00087 G4double dEdx; 00088 00089 if(tau<taul) { 00090 G4double t1 = taul+1.; 00091 G4double t2 = taul+2.; 00092 G4double tsq = taul*taul; 00093 G4double beta2 = taul*t2/(t1*t1); 00094 G4double f = 1.-beta2+std::log(tsq/2.) 00095 +(0.5+0.25*tsq+(1.+2.*taul)*std::log(0.5))/(t1*t1); 00096 dEdx = (std::log(2.*taul+4.)-2.*ionpotlog+f)/beta2; 00097 dEdx = twopi_mc2_rcl2*Z*dEdx; 00098 G4double clow = dEdx*std::sqrt(taul); 00099 dEdx = clow/std::sqrt(KineticEnergy/Mass); 00100 00101 } else { 00102 G4double t1 = tau+1.; 00103 G4double t2 = tau+2.; 00104 G4double tsq = tau*tau; 00105 G4double beta2 = tau*t2/(t1*t1); 00106 G4double f = 1.-beta2+std::log(tsq/2.) 00107 +(0.5+0.25*tsq+(1.+2.*tau)*std::log(0.5))/(t1*t1); 00108 dEdx = (std::log(2.*tau+4.)-2.*ionpotlog+f)/beta2; 00109 dEdx = twopi_mc2_rcl2*Z*dEdx; 00110 00111 // loss from bremsstrahlung follows 00112 G4double cbrem = (cbr1+cbr2*Z) 00113 *(cbr3+cbr4*std::log(KineticEnergy/Thigh)); 00114 cbrem = Z*(Z+1.)*cbrem*tau/beta2; 00115 00116 cbrem *= bremfactor ; 00117 00118 dEdx += twopi_mc2_rcl2*cbrem; 00119 } 00120 00121 return dEdx; 00122 }