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1 // 1 2 // ******************************************* 3 // * License and Disclaimer 4 // * 5 // * The Geant4 software is copyright of th 6 // * the Geant4 Collaboration. It is provided 7 // * conditions of the Geant4 Software License 8 // * LICENSE and available at http://cern.ch/ 9 // * include a list of copyright holders. 10 // * 11 // * Neither the authors of this software syst 12 // * institutes,nor the agencies providing fin 13 // * work make any representation or warran 14 // * regarding this software system or assum 15 // * use. Please see the license in the file 16 // * for the full disclaimer and the limitatio 17 // * 18 // * This code implementation is the result 19 // * technical work of the GEANT4 collaboratio 20 // * By using, copying, modifying or distri 21 // * any work based on the software) you ag 22 // * use in resulting scientific publicati 23 // * acceptance of all terms of the Geant4 Sof 24 // ******************************************* 25 // 26 // G4RToEConvForGamma class implementation 27 // 28 // Author: H.Kurashige, 05 October 2002 - Firs 29 // ------------------------------------------- 30 31 #include "G4RToEConvForGamma.hh" 32 #include "G4ParticleDefinition.hh" 33 #include "G4ParticleTable.hh" 34 #include "G4SystemOfUnits.hh" 35 #include "G4Log.hh" 36 #include "G4Exp.hh" 37 #include "G4Pow.hh" 38 39 // ------------------------------------------- 40 G4RToEConvForGamma::G4RToEConvForGamma() 41 : G4VRangeToEnergyConverter() 42 { 43 theParticle = G4ParticleTable::GetParticleTa 44 if (theParticle == nullptr) 45 { 46 #ifdef G4VERBOSE 47 if (GetVerboseLevel()>0) 48 { 49 G4cout << " G4RToEConvForGamma::G4RToECo 50 G4cout << "Gamma is not defined !!" << G 51 } 52 #endif 53 } 54 else 55 { 56 fPDG = theParticle->GetPDGEncoding(); 57 } 58 } 59 60 // ------------------------------------------- 61 G4RToEConvForGamma::~G4RToEConvForGamma() 62 {} 63 64 // ------------------------------------------- 65 G4double G4RToEConvForGamma::ComputeValue(cons 66 cons 67 { 68 // Compute the "absorption" cross-section of 69 // Cross-section means here the sum of the c 70 // pair production, Compton scattering and p 71 72 const G4double t1keV = 1.*CLHEP::keV; 73 const G4double t200keV = 200.*CLHEP::keV; 74 const G4double t100MeV = 100.*CLHEP::MeV; 75 76 G4double Zsquare = Z*Z; 77 G4double Zlog = G4Pow::GetInstance()->logZ(Z 78 G4double Zlogsquare = Zlog*Zlog; 79 80 G4double tmin = (0.552+218.5/Z+557.17/Zsquar 81 G4double tlow = 0.2*G4Exp(-7.355/std::sqrt(Z 82 83 G4double smin = (0.01239+0.005585*Zlog-0.000 84 G4double s200keV = (0.2651-0.1501*Zlog+0.022 85 86 G4double cminlog = G4Log(tmin/t200keV); 87 G4double cmin = G4Log(s200keV/smin)/(cminlog 88 89 G4double slowlog = G4Log(t200keV/tlow); 90 G4double slow = s200keV * G4Exp(0.042*Z*slow 91 G4double logtlow = G4Log(tlow/t1keV); 92 G4double clow = G4Log(300.*Zsquare/slow)/log 93 G4double chigh = (7.55e-5 - 0.0542e-5*Z)*Zsq 94 95 // Calculate the cross-section (using an app 96 G4double xs; 97 if ( energy < tlow ) 98 { 99 xs = (energy < t1keV) ? slow*G4Exp(clow*lo 100 slow*G4Exp(clow*G4Log(tlow/energy)); 101 } 102 else if ( energy < t200keV ) 103 { 104 G4double x = G4Log(t200keV/energy); 105 xs = s200keV * G4Exp(0.042*Z*x*x); 106 } 107 else if( energy<tmin ) 108 { 109 const G4double x = G4Log(tmin/energy); 110 xs = smin * G4Exp(cmin*x*x); 111 } 112 else 113 { 114 xs = smin + chigh*G4Log(energy/tmin); 115 } 116 return xs * CLHEP::barn; 117 } 118 119 // ------------------------------------------- 120