[1197] | 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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[1340] | 27 | // $Id: G4UrbanMscModel92.cc,v 1.2 2010/10/26 10:06:12 vnivanch Exp $ |
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| 28 | // GEANT4 tag $Name: emstand-V09-03-24 $ |
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[1197] | 29 | // |
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| 30 | // ------------------------------------------------------------------- |
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| 31 | // |
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| 32 | // GEANT4 Class file |
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| 33 | // |
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| 34 | // |
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| 35 | // File name: G4UrbanMscModel92 |
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| 36 | // |
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| 37 | // Author: Laszlo Urban |
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| 38 | // |
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| 39 | // Creation date: 06.03.2008 |
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| 40 | // |
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| 41 | // Modifications: |
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| 42 | // |
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| 43 | // 06-03-2008 starting point : G4UrbanMscModel2 = G4UrbanMscModel 9.1 ref 02 |
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| 44 | // |
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| 45 | // 13-03-08 Bug in SampleScattering (which caused lateral asymmetry) fixed |
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| 46 | // (L.Urban) |
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| 47 | // |
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| 48 | // 14-03-08 Simplification of step limitation in ComputeTruePathLengthLimit, |
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| 49 | // + tlimitmin is the same for UseDistancetoBoundary and |
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| 50 | // UseSafety (L.Urban) |
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| 51 | // |
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| 52 | // 16-03-08 Reorganization of SampleCosineTheta + new method SimpleScattering |
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| 53 | // SimpleScattering is used if the relative energy loss is too big |
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| 54 | // or theta0 is too big (see data members rellossmax, theta0max) |
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| 55 | // (L.Urban) |
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| 56 | // |
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| 57 | // 17-03-08 tuning of the correction factor in ComputeTheta0 (L.Urban) |
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| 58 | // |
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| 59 | // 19-03-08 exponent c of the 'tail' model function is not equal to 2 any more, |
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| 60 | // value of c has been extracted from some e- scattering data (L.Urban) |
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| 61 | // |
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| 62 | // 24-03-08 Step limitation in ComputeTruePathLengthLimit has been |
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| 63 | // simplified further + some data members have been removed (L.Urban) |
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| 64 | // |
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| 65 | // 24-07-08 central part of scattering angle (theta0) has been tuned |
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| 66 | // tail of the scattering angle distribution has been tuned |
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| 67 | // using some e- and proton scattering data |
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| 68 | // |
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| 69 | // 05-08-08 bugfix in ComputeTruePathLengthLimit (L.Urban) |
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| 70 | // |
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| 71 | // 09-10-08 theta0 and tail have been retuned using some e-,mu,proton |
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| 72 | // scattering data (L.Urban) |
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| 73 | // + single scattering without path length correction for |
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| 74 | // small steps (t < tlimitmin, for UseDistanceToBoundary only) |
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| 75 | // |
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| 76 | // 15-10-08 Moliere-Bethe screening in the single scattering part(L.Urban) |
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| 77 | // |
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| 78 | // 17-10-08 stepping similar to that in model (9.1) for UseSafety case |
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| 79 | // for e+/e- in order to speed up the code for calorimeters |
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| 80 | // |
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| 81 | // 23-10-08 bugfix in the screeningparameter of the single scattering part, |
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| 82 | // some technical change in order to speed up the code (UpdateCache) |
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| 83 | // |
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| 84 | // 27-10-08 bugfix in ComputeTruePathLengthLimit (affects UseDistanceToBoundary |
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| 85 | // stepping type only) (L.Urban) |
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| 86 | // |
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| 87 | // 28-10-09 V.Ivanchenko moved G4UrbanMscModel to G4UrbanMscModel92, |
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| 88 | // now it is a frozen version of the Urban model corresponding |
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| 89 | // to g4 9.2 |
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| 90 | |
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| 91 | // Class Description: |
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| 92 | // |
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| 93 | // Implementation of the model of multiple scattering based on |
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| 94 | // H.W.Lewis Phys Rev 78 (1950) 526 and others |
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| 95 | |
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| 96 | // ------------------------------------------------------------------- |
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| 97 | // In its present form the model can be used for simulation |
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| 98 | // of the e-/e+, muon and charged hadron multiple scattering |
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| 99 | // |
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| 100 | |
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| 101 | |
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| 102 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 103 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 104 | |
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| 105 | #include "G4UrbanMscModel92.hh" |
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| 106 | #include "Randomize.hh" |
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| 107 | #include "G4Electron.hh" |
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| 108 | #include "G4LossTableManager.hh" |
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| 109 | #include "G4ParticleChangeForMSC.hh" |
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| 110 | |
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| 111 | #include "G4Poisson.hh" |
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| 112 | #include "globals.hh" |
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| 113 | |
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| 114 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 115 | |
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| 116 | using namespace std; |
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| 117 | |
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| 118 | G4UrbanMscModel92::G4UrbanMscModel92(const G4String& nam) |
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| 119 | : G4VMscModel(nam), |
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| 120 | isInitialized(false) |
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| 121 | { |
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| 122 | masslimite = 0.6*MeV; |
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| 123 | lambdalimit = 1.*mm; |
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| 124 | fr = 0.02; |
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| 125 | // facsafety = 0.3; |
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| 126 | taubig = 8.0; |
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| 127 | tausmall = 1.e-16; |
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| 128 | taulim = 1.e-6; |
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| 129 | currentTau = taulim; |
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| 130 | tlimitminfix = 1.e-6*mm; |
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| 131 | stepmin = tlimitminfix; |
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| 132 | smallstep = 1.e10; |
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| 133 | currentRange = 0. ; |
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| 134 | rangeinit = 0.; |
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| 135 | tlimit = 1.e10*mm; |
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| 136 | tlimitmin = 10.*tlimitminfix; |
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| 137 | tgeom = 1.e50*mm; |
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| 138 | geombig = 1.e50*mm; |
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| 139 | geommin = 1.e-3*mm; |
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| 140 | geomlimit = geombig; |
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| 141 | presafety = 0.*mm; |
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| 142 | |
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| 143 | y = 0.; |
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| 144 | |
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| 145 | Zold = 0.; |
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| 146 | Zeff = 1.; |
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| 147 | Z2 = 1.; |
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| 148 | Z23 = 1.; |
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| 149 | lnZ = 0.; |
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| 150 | coeffth1 = 0.; |
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| 151 | coeffth2 = 0.; |
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| 152 | coeffc1 = 0.; |
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| 153 | coeffc2 = 0.; |
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| 154 | scr1ini = fine_structure_const*fine_structure_const* |
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| 155 | electron_mass_c2*electron_mass_c2/(0.885*0.885*4.*pi); |
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| 156 | scr2ini = 3.76*fine_structure_const*fine_structure_const; |
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| 157 | scr1 = 0.; |
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| 158 | scr2 = 0.; |
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| 159 | |
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| 160 | theta0max = pi/6.; |
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| 161 | rellossmax = 0.50; |
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| 162 | third = 1./3.; |
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| 163 | particle = 0; |
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| 164 | theManager = G4LossTableManager::Instance(); |
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| 165 | inside = false; |
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| 166 | insideskin = false; |
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| 167 | |
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[1340] | 168 | skindepth = skin*stepmin; |
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| 169 | |
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| 170 | mass = proton_mass_c2; |
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| 171 | charge = ChargeSquare = 1.0; |
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| 172 | currentKinEnergy = currentRadLength = lambda0 = lambdaeff = tPathLength |
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| 173 | = zPathLength = par1 = par2 = par3 = 0; |
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| 174 | |
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| 175 | currentMaterialIndex = 0; |
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[1197] | 176 | } |
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| 177 | |
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| 178 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 179 | |
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| 180 | G4UrbanMscModel92::~G4UrbanMscModel92() |
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| 181 | {} |
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| 182 | |
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| 183 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 184 | |
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| 185 | void G4UrbanMscModel92::Initialise(const G4ParticleDefinition* p, |
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| 186 | const G4DataVector&) |
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| 187 | { |
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| 188 | skindepth = skin*stepmin; |
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| 189 | if(isInitialized) return; |
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| 190 | // set values of some data members |
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| 191 | SetParticle(p); |
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| 192 | |
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| 193 | fParticleChange = GetParticleChangeForMSC(); |
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| 194 | InitialiseSafetyHelper(); |
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| 195 | |
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| 196 | isInitialized = true; |
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| 197 | } |
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| 198 | |
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| 199 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 200 | |
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| 201 | G4double G4UrbanMscModel92::ComputeCrossSectionPerAtom( |
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| 202 | const G4ParticleDefinition* part, |
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| 203 | G4double KineticEnergy, |
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| 204 | G4double AtomicNumber,G4double, |
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| 205 | G4double, G4double) |
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| 206 | { |
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| 207 | const G4double sigmafactor = twopi*classic_electr_radius*classic_electr_radius; |
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| 208 | const G4double epsfactor = 2.*electron_mass_c2*electron_mass_c2* |
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| 209 | Bohr_radius*Bohr_radius/(hbarc*hbarc); |
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| 210 | const G4double epsmin = 1.e-4 , epsmax = 1.e10; |
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| 211 | |
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| 212 | const G4double Zdat[15] = { 4., 6., 13., 20., 26., 29., 32., 38., 47., |
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| 213 | 50., 56., 64., 74., 79., 82. }; |
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| 214 | |
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| 215 | const G4double Tdat[22] = { 100*eV, 200*eV, 400*eV, 700*eV, |
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| 216 | 1*keV, 2*keV, 4*keV, 7*keV, |
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| 217 | 10*keV, 20*keV, 40*keV, 70*keV, |
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| 218 | 100*keV, 200*keV, 400*keV, 700*keV, |
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| 219 | 1*MeV, 2*MeV, 4*MeV, 7*MeV, |
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| 220 | 10*MeV, 20*MeV}; |
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| 221 | |
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| 222 | // corr. factors for e-/e+ lambda for T <= Tlim |
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| 223 | G4double celectron[15][22] = |
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| 224 | {{1.125,1.072,1.051,1.047,1.047,1.050,1.052,1.054, |
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| 225 | 1.054,1.057,1.062,1.069,1.075,1.090,1.105,1.111, |
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| 226 | 1.112,1.108,1.100,1.093,1.089,1.087 }, |
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| 227 | {1.408,1.246,1.143,1.096,1.077,1.059,1.053,1.051, |
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| 228 | 1.052,1.053,1.058,1.065,1.072,1.087,1.101,1.108, |
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| 229 | 1.109,1.105,1.097,1.090,1.086,1.082 }, |
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| 230 | {2.833,2.268,1.861,1.612,1.486,1.309,1.204,1.156, |
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| 231 | 1.136,1.114,1.106,1.106,1.109,1.119,1.129,1.132, |
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| 232 | 1.131,1.124,1.113,1.104,1.099,1.098 }, |
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| 233 | {3.879,3.016,2.380,2.007,1.818,1.535,1.340,1.236, |
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| 234 | 1.190,1.133,1.107,1.099,1.098,1.103,1.110,1.113, |
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| 235 | 1.112,1.105,1.096,1.089,1.085,1.098 }, |
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| 236 | {6.937,4.330,2.886,2.256,1.987,1.628,1.395,1.265, |
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| 237 | 1.203,1.122,1.080,1.065,1.061,1.063,1.070,1.073, |
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| 238 | 1.073,1.070,1.064,1.059,1.056,1.056 }, |
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| 239 | {9.616,5.708,3.424,2.551,2.204,1.762,1.485,1.330, |
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| 240 | 1.256,1.155,1.099,1.077,1.070,1.068,1.072,1.074, |
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| 241 | 1.074,1.070,1.063,1.059,1.056,1.052 }, |
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| 242 | {11.72,6.364,3.811,2.806,2.401,1.884,1.564,1.386, |
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| 243 | 1.300,1.180,1.112,1.082,1.073,1.066,1.068,1.069, |
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| 244 | 1.068,1.064,1.059,1.054,1.051,1.050 }, |
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| 245 | {18.08,8.601,4.569,3.183,2.662,2.025,1.646,1.439, |
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| 246 | 1.339,1.195,1.108,1.068,1.053,1.040,1.039,1.039, |
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| 247 | 1.039,1.037,1.034,1.031,1.030,1.036 }, |
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| 248 | {18.22,10.48,5.333,3.713,3.115,2.367,1.898,1.631, |
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| 249 | 1.498,1.301,1.171,1.105,1.077,1.048,1.036,1.033, |
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| 250 | 1.031,1.028,1.024,1.022,1.021,1.024 }, |
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| 251 | {14.14,10.65,5.710,3.929,3.266,2.453,1.951,1.669, |
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| 252 | 1.528,1.319,1.178,1.106,1.075,1.040,1.027,1.022, |
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| 253 | 1.020,1.017,1.015,1.013,1.013,1.020 }, |
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| 254 | {14.11,11.73,6.312,4.240,3.478,2.566,2.022,1.720, |
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| 255 | 1.569,1.342,1.186,1.102,1.065,1.022,1.003,0.997, |
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| 256 | 0.995,0.993,0.993,0.993,0.993,1.011 }, |
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| 257 | {22.76,20.01,8.835,5.287,4.144,2.901,2.219,1.855, |
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| 258 | 1.677,1.410,1.224,1.121,1.073,1.014,0.986,0.976, |
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| 259 | 0.974,0.972,0.973,0.974,0.975,0.987 }, |
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| 260 | {50.77,40.85,14.13,7.184,5.284,3.435,2.520,2.059, |
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| 261 | 1.837,1.512,1.283,1.153,1.091,1.010,0.969,0.954, |
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| 262 | 0.950,0.947,0.949,0.952,0.954,0.963 }, |
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| 263 | {65.87,59.06,15.87,7.570,5.567,3.650,2.682,2.182, |
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| 264 | 1.939,1.579,1.325,1.178,1.108,1.014,0.965,0.947, |
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| 265 | 0.941,0.938,0.940,0.944,0.946,0.954 }, |
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| 266 | {55.60,47.34,15.92,7.810,5.755,3.767,2.760,2.239, |
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| 267 | 1.985,1.609,1.343,1.188,1.113,1.013,0.960,0.939, |
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| 268 | 0.933,0.930,0.933,0.936,0.939,0.949 }}; |
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| 269 | |
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| 270 | G4double cpositron[15][22] = { |
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| 271 | {2.589,2.044,1.658,1.446,1.347,1.217,1.144,1.110, |
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| 272 | 1.097,1.083,1.080,1.086,1.092,1.108,1.123,1.131, |
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| 273 | 1.131,1.126,1.117,1.108,1.103,1.100 }, |
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| 274 | {3.904,2.794,2.079,1.710,1.543,1.325,1.202,1.145, |
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| 275 | 1.122,1.096,1.089,1.092,1.098,1.114,1.130,1.137, |
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| 276 | 1.138,1.132,1.122,1.113,1.108,1.102 }, |
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| 277 | {7.970,6.080,4.442,3.398,2.872,2.127,1.672,1.451, |
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| 278 | 1.357,1.246,1.194,1.179,1.178,1.188,1.201,1.205, |
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| 279 | 1.203,1.190,1.173,1.159,1.151,1.145 }, |
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| 280 | {9.714,7.607,5.747,4.493,3.815,2.777,2.079,1.715, |
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| 281 | 1.553,1.353,1.253,1.219,1.211,1.214,1.225,1.228, |
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| 282 | 1.225,1.210,1.191,1.175,1.166,1.174 }, |
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| 283 | {17.97,12.95,8.628,6.065,4.849,3.222,2.275,1.820, |
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| 284 | 1.624,1.382,1.259,1.214,1.202,1.202,1.214,1.219, |
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| 285 | 1.217,1.203,1.184,1.169,1.160,1.151 }, |
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| 286 | {24.83,17.06,10.84,7.355,5.767,3.707,2.546,1.996, |
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| 287 | 1.759,1.465,1.311,1.252,1.234,1.228,1.238,1.241, |
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| 288 | 1.237,1.222,1.201,1.184,1.174,1.159 }, |
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| 289 | {23.26,17.15,11.52,8.049,6.375,4.114,2.792,2.155, |
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| 290 | 1.880,1.535,1.353,1.281,1.258,1.247,1.254,1.256, |
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| 291 | 1.252,1.234,1.212,1.194,1.183,1.170 }, |
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| 292 | {22.33,18.01,12.86,9.212,7.336,4.702,3.117,2.348, |
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| 293 | 2.015,1.602,1.385,1.297,1.268,1.251,1.256,1.258, |
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| 294 | 1.254,1.237,1.214,1.195,1.185,1.179 }, |
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| 295 | {33.91,24.13,15.71,10.80,8.507,5.467,3.692,2.808, |
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| 296 | 2.407,1.873,1.564,1.425,1.374,1.330,1.324,1.320, |
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| 297 | 1.312,1.288,1.258,1.235,1.221,1.205 }, |
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| 298 | {32.14,24.11,16.30,11.40,9.015,5.782,3.868,2.917, |
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| 299 | 2.490,1.925,1.596,1.447,1.391,1.342,1.332,1.327, |
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| 300 | 1.320,1.294,1.264,1.240,1.226,1.214 }, |
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| 301 | {29.51,24.07,17.19,12.28,9.766,6.238,4.112,3.066, |
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| 302 | 2.602,1.995,1.641,1.477,1.414,1.356,1.342,1.336, |
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| 303 | 1.328,1.302,1.270,1.245,1.231,1.233 }, |
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| 304 | {38.19,30.85,21.76,15.35,12.07,7.521,4.812,3.498, |
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| 305 | 2.926,2.188,1.763,1.563,1.484,1.405,1.382,1.371, |
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| 306 | 1.361,1.330,1.294,1.267,1.251,1.239 }, |
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| 307 | {49.71,39.80,27.96,19.63,15.36,9.407,5.863,4.155, |
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| 308 | 3.417,2.478,1.944,1.692,1.589,1.480,1.441,1.423, |
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| 309 | 1.409,1.372,1.330,1.298,1.280,1.258 }, |
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| 310 | {59.25,45.08,30.36,20.83,16.15,9.834,6.166,4.407, |
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| 311 | 3.641,2.648,2.064,1.779,1.661,1.531,1.482,1.459, |
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| 312 | 1.442,1.400,1.354,1.319,1.299,1.272 }, |
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| 313 | {56.38,44.29,30.50,21.18,16.51,10.11,6.354,4.542, |
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| 314 | 3.752,2.724,2.116,1.817,1.692,1.554,1.499,1.474, |
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| 315 | 1.456,1.412,1.364,1.328,1.307,1.282 }}; |
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| 316 | |
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| 317 | //data/corrections for T > Tlim |
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| 318 | G4double Tlim = 10.*MeV; |
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| 319 | G4double beta2lim = Tlim*(Tlim+2.*electron_mass_c2)/ |
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| 320 | ((Tlim+electron_mass_c2)*(Tlim+electron_mass_c2)); |
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| 321 | G4double bg2lim = Tlim*(Tlim+2.*electron_mass_c2)/ |
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| 322 | (electron_mass_c2*electron_mass_c2); |
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| 323 | |
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| 324 | G4double sig0[15] = {0.2672*barn, 0.5922*barn, 2.653*barn, 6.235*barn, |
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| 325 | 11.69*barn , 13.24*barn , 16.12*barn, 23.00*barn , |
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| 326 | 35.13*barn , 39.95*barn , 50.85*barn, 67.19*barn , |
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| 327 | 91.15*barn , 104.4*barn , 113.1*barn}; |
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| 328 | |
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| 329 | G4double hecorr[15] = {120.70, 117.50, 105.00, 92.92, 79.23, 74.510, 68.29, |
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| 330 | 57.39, 41.97, 36.14, 24.53, 10.21, -7.855, -16.84, |
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| 331 | -22.30}; |
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| 332 | |
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| 333 | G4double sigma; |
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| 334 | SetParticle(part); |
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| 335 | |
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| 336 | G4double Z23 = 2.*log(AtomicNumber)/3.; Z23 = exp(Z23); |
---|
| 337 | |
---|
| 338 | // correction if particle .ne. e-/e+ |
---|
| 339 | // compute equivalent kinetic energy |
---|
| 340 | // lambda depends on p*beta .... |
---|
| 341 | |
---|
| 342 | G4double eKineticEnergy = KineticEnergy; |
---|
| 343 | |
---|
| 344 | if(mass > electron_mass_c2) |
---|
| 345 | { |
---|
| 346 | G4double TAU = KineticEnergy/mass ; |
---|
| 347 | G4double c = mass*TAU*(TAU+2.)/(electron_mass_c2*(TAU+1.)) ; |
---|
| 348 | G4double w = c-2. ; |
---|
| 349 | G4double tau = 0.5*(w+sqrt(w*w+4.*c)) ; |
---|
| 350 | eKineticEnergy = electron_mass_c2*tau ; |
---|
| 351 | } |
---|
| 352 | |
---|
| 353 | G4double eTotalEnergy = eKineticEnergy + electron_mass_c2 ; |
---|
| 354 | G4double beta2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2) |
---|
| 355 | /(eTotalEnergy*eTotalEnergy); |
---|
| 356 | G4double bg2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2) |
---|
| 357 | /(electron_mass_c2*electron_mass_c2); |
---|
| 358 | |
---|
| 359 | G4double eps = epsfactor*bg2/Z23; |
---|
| 360 | |
---|
| 361 | if (eps<epsmin) sigma = 2.*eps*eps; |
---|
| 362 | else if(eps<epsmax) sigma = log(1.+2.*eps)-2.*eps/(1.+2.*eps); |
---|
| 363 | else sigma = log(2.*eps)-1.+1./eps; |
---|
| 364 | |
---|
| 365 | sigma *= ChargeSquare*AtomicNumber*AtomicNumber/(beta2*bg2); |
---|
| 366 | |
---|
| 367 | // interpolate in AtomicNumber and beta2 |
---|
| 368 | G4double c1,c2,cc1,cc2,corr; |
---|
| 369 | |
---|
| 370 | // get bin number in Z |
---|
| 371 | G4int iZ = 14; |
---|
| 372 | while ((iZ>=0)&&(Zdat[iZ]>=AtomicNumber)) iZ -= 1; |
---|
| 373 | if (iZ==14) iZ = 13; |
---|
| 374 | if (iZ==-1) iZ = 0 ; |
---|
| 375 | |
---|
| 376 | G4double Z1 = Zdat[iZ]; |
---|
| 377 | G4double Z2 = Zdat[iZ+1]; |
---|
| 378 | G4double ratZ = (AtomicNumber-Z1)*(AtomicNumber+Z1)/ |
---|
| 379 | ((Z2-Z1)*(Z2+Z1)); |
---|
| 380 | |
---|
| 381 | if(eKineticEnergy <= Tlim) |
---|
| 382 | { |
---|
| 383 | // get bin number in T (beta2) |
---|
| 384 | G4int iT = 21; |
---|
| 385 | while ((iT>=0)&&(Tdat[iT]>=eKineticEnergy)) iT -= 1; |
---|
| 386 | if(iT==21) iT = 20; |
---|
| 387 | if(iT==-1) iT = 0 ; |
---|
| 388 | |
---|
| 389 | // calculate betasquare values |
---|
| 390 | G4double T = Tdat[iT], E = T + electron_mass_c2; |
---|
| 391 | G4double b2small = T*(E+electron_mass_c2)/(E*E); |
---|
| 392 | |
---|
| 393 | T = Tdat[iT+1]; E = T + electron_mass_c2; |
---|
| 394 | G4double b2big = T*(E+electron_mass_c2)/(E*E); |
---|
| 395 | G4double ratb2 = (beta2-b2small)/(b2big-b2small); |
---|
| 396 | |
---|
| 397 | if (charge < 0.) |
---|
| 398 | { |
---|
| 399 | c1 = celectron[iZ][iT]; |
---|
| 400 | c2 = celectron[iZ+1][iT]; |
---|
| 401 | cc1 = c1+ratZ*(c2-c1); |
---|
| 402 | |
---|
| 403 | c1 = celectron[iZ][iT+1]; |
---|
| 404 | c2 = celectron[iZ+1][iT+1]; |
---|
| 405 | cc2 = c1+ratZ*(c2-c1); |
---|
| 406 | |
---|
| 407 | corr = cc1+ratb2*(cc2-cc1); |
---|
| 408 | |
---|
| 409 | sigma *= sigmafactor/corr; |
---|
| 410 | } |
---|
| 411 | else |
---|
| 412 | { |
---|
| 413 | c1 = cpositron[iZ][iT]; |
---|
| 414 | c2 = cpositron[iZ+1][iT]; |
---|
| 415 | cc1 = c1+ratZ*(c2-c1); |
---|
| 416 | |
---|
| 417 | c1 = cpositron[iZ][iT+1]; |
---|
| 418 | c2 = cpositron[iZ+1][iT+1]; |
---|
| 419 | cc2 = c1+ratZ*(c2-c1); |
---|
| 420 | |
---|
| 421 | corr = cc1+ratb2*(cc2-cc1); |
---|
| 422 | |
---|
| 423 | sigma *= sigmafactor/corr; |
---|
| 424 | } |
---|
| 425 | } |
---|
| 426 | else |
---|
| 427 | { |
---|
| 428 | c1 = bg2lim*sig0[iZ]*(1.+hecorr[iZ]*(beta2-beta2lim))/bg2; |
---|
| 429 | c2 = bg2lim*sig0[iZ+1]*(1.+hecorr[iZ+1]*(beta2-beta2lim))/bg2; |
---|
| 430 | if((AtomicNumber >= Z1) && (AtomicNumber <= Z2)) |
---|
| 431 | sigma = c1+ratZ*(c2-c1) ; |
---|
| 432 | else if(AtomicNumber < Z1) |
---|
| 433 | sigma = AtomicNumber*AtomicNumber*c1/(Z1*Z1); |
---|
| 434 | else if(AtomicNumber > Z2) |
---|
| 435 | sigma = AtomicNumber*AtomicNumber*c2/(Z2*Z2); |
---|
| 436 | } |
---|
| 437 | return sigma; |
---|
| 438 | |
---|
| 439 | } |
---|
| 440 | |
---|
| 441 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 442 | |
---|
| 443 | G4double G4UrbanMscModel92::ComputeTruePathLengthLimit( |
---|
| 444 | const G4Track& track, |
---|
| 445 | G4PhysicsTable* theTable, |
---|
| 446 | G4double currentMinimalStep) |
---|
| 447 | { |
---|
| 448 | tPathLength = currentMinimalStep; |
---|
| 449 | G4StepPoint* sp = track.GetStep()->GetPreStepPoint(); |
---|
| 450 | G4StepStatus stepStatus = sp->GetStepStatus(); |
---|
| 451 | |
---|
| 452 | const G4DynamicParticle* dp = track.GetDynamicParticle(); |
---|
| 453 | |
---|
| 454 | if(stepStatus == fUndefined) { |
---|
| 455 | inside = false; |
---|
| 456 | insideskin = false; |
---|
| 457 | tlimit = geombig; |
---|
| 458 | SetParticle( dp->GetDefinition() ); |
---|
| 459 | } |
---|
| 460 | |
---|
| 461 | theLambdaTable = theTable; |
---|
| 462 | couple = track.GetMaterialCutsCouple(); |
---|
| 463 | currentMaterialIndex = couple->GetIndex(); |
---|
| 464 | currentKinEnergy = dp->GetKineticEnergy(); |
---|
| 465 | currentRange = |
---|
| 466 | theManager->GetRangeFromRestricteDEDX(particle,currentKinEnergy,couple); |
---|
| 467 | lambda0 = GetLambda(currentKinEnergy); |
---|
| 468 | |
---|
| 469 | // stop here if small range particle |
---|
| 470 | if(inside) return tPathLength; |
---|
| 471 | |
---|
| 472 | if(tPathLength > currentRange) tPathLength = currentRange; |
---|
| 473 | |
---|
| 474 | presafety = sp->GetSafety(); |
---|
| 475 | |
---|
| 476 | // G4cout << "G4UrbanMscModel92::ComputeTruePathLengthLimit tPathLength= " |
---|
| 477 | // <<tPathLength<<" safety= " << presafety |
---|
| 478 | // << " range= " <<currentRange<<G4endl; |
---|
| 479 | |
---|
| 480 | // far from geometry boundary |
---|
| 481 | if(currentRange < presafety) |
---|
| 482 | { |
---|
| 483 | inside = true; |
---|
| 484 | return tPathLength; |
---|
| 485 | } |
---|
| 486 | |
---|
| 487 | // standard version |
---|
| 488 | // |
---|
| 489 | if (steppingAlgorithm == fUseDistanceToBoundary) |
---|
| 490 | { |
---|
| 491 | //compute geomlimit and presafety |
---|
| 492 | G4double geomlimit = ComputeGeomLimit(track, presafety, currentRange); |
---|
| 493 | |
---|
| 494 | // is it far from boundary ? |
---|
| 495 | if(currentRange < presafety) |
---|
| 496 | { |
---|
| 497 | inside = true; |
---|
| 498 | return tPathLength; |
---|
| 499 | } |
---|
| 500 | |
---|
| 501 | smallstep += 1.; |
---|
| 502 | insideskin = false; |
---|
| 503 | |
---|
| 504 | if((stepStatus == fGeomBoundary) || (stepStatus == fUndefined)) |
---|
| 505 | { |
---|
| 506 | rangeinit = currentRange; |
---|
| 507 | if(stepStatus == fUndefined) smallstep = 1.e10; |
---|
| 508 | else smallstep = 1.; |
---|
| 509 | |
---|
| 510 | // constraint from the geometry |
---|
| 511 | if((geomlimit < geombig) && (geomlimit > geommin)) |
---|
| 512 | { |
---|
| 513 | if(stepStatus == fGeomBoundary) |
---|
| 514 | tgeom = geomlimit/facgeom; |
---|
| 515 | else |
---|
| 516 | tgeom = 2.*geomlimit/facgeom; |
---|
| 517 | } |
---|
| 518 | else |
---|
| 519 | tgeom = geombig; |
---|
| 520 | |
---|
| 521 | //define stepmin here (it depends on lambda!) |
---|
| 522 | //rough estimation of lambda_elastic/lambda_transport |
---|
| 523 | G4double rat = currentKinEnergy/MeV ; |
---|
| 524 | rat = 1.e-3/(rat*(10.+rat)) ; |
---|
| 525 | //stepmin ~ lambda_elastic |
---|
| 526 | stepmin = rat*lambda0; |
---|
| 527 | skindepth = skin*stepmin; |
---|
| 528 | |
---|
| 529 | //define tlimitmin |
---|
| 530 | tlimitmin = 10.*stepmin; |
---|
| 531 | if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix; |
---|
| 532 | |
---|
| 533 | } |
---|
| 534 | |
---|
| 535 | //step limit |
---|
| 536 | tlimit = facrange*rangeinit; |
---|
| 537 | if(tlimit < facsafety*presafety) |
---|
| 538 | tlimit = facsafety*presafety; |
---|
| 539 | |
---|
| 540 | //lower limit for tlimit |
---|
| 541 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
| 542 | |
---|
| 543 | if(tlimit > tgeom) tlimit = tgeom; |
---|
| 544 | |
---|
| 545 | // G4cout << "tgeom= " << tgeom << " geomlimit= " << geomlimit |
---|
| 546 | // << " tlimit= " << tlimit << " presafety= " << presafety << G4endl; |
---|
| 547 | |
---|
| 548 | // shortcut |
---|
| 549 | if((tPathLength < tlimit) && (tPathLength < presafety) && |
---|
| 550 | (smallstep >= skin) && (tPathLength < geomlimit-0.999*skindepth)) |
---|
| 551 | return tPathLength; |
---|
| 552 | |
---|
| 553 | // step reduction near to boundary |
---|
| 554 | if(smallstep < skin) |
---|
| 555 | { |
---|
| 556 | tlimit = stepmin; |
---|
| 557 | insideskin = true; |
---|
| 558 | } |
---|
| 559 | else if(geomlimit < geombig) |
---|
| 560 | { |
---|
| 561 | if(geomlimit > skindepth) |
---|
| 562 | { |
---|
| 563 | if(tlimit > geomlimit-0.999*skindepth) |
---|
| 564 | tlimit = geomlimit-0.999*skindepth; |
---|
| 565 | } |
---|
| 566 | else |
---|
| 567 | { |
---|
| 568 | insideskin = true; |
---|
| 569 | if(tlimit > stepmin) tlimit = stepmin; |
---|
| 570 | } |
---|
| 571 | } |
---|
| 572 | |
---|
| 573 | if(tlimit < stepmin) tlimit = stepmin; |
---|
| 574 | |
---|
| 575 | if(tPathLength > tlimit) tPathLength = tlimit ; |
---|
| 576 | |
---|
| 577 | } |
---|
| 578 | // for 'normal' simulation with or without magnetic field |
---|
| 579 | // there no small step/single scattering at boundaries |
---|
| 580 | else if(steppingAlgorithm == fUseSafety) |
---|
| 581 | { |
---|
| 582 | // compute presafety again if presafety <= 0 and no boundary |
---|
| 583 | // i.e. when it is needed for optimization purposes |
---|
| 584 | if((stepStatus != fGeomBoundary) && (presafety < tlimitminfix)) |
---|
| 585 | presafety = ComputeSafety(sp->GetPosition(),tPathLength); |
---|
| 586 | |
---|
| 587 | // is far from boundary |
---|
| 588 | if(currentRange < presafety) |
---|
| 589 | { |
---|
| 590 | inside = true; |
---|
| 591 | return tPathLength; |
---|
| 592 | } |
---|
| 593 | |
---|
| 594 | if((stepStatus == fGeomBoundary) || (stepStatus == fUndefined)) |
---|
| 595 | { |
---|
| 596 | rangeinit = currentRange; |
---|
| 597 | fr = facrange; |
---|
| 598 | // 9.1 like stepping for e+/e- only (not for muons,hadrons) |
---|
| 599 | if(mass < masslimite) |
---|
| 600 | { |
---|
| 601 | if(lambda0 > currentRange) |
---|
| 602 | rangeinit = lambda0; |
---|
| 603 | if(lambda0 > lambdalimit) |
---|
| 604 | fr *= 0.75+0.25*lambda0/lambdalimit; |
---|
| 605 | } |
---|
| 606 | |
---|
| 607 | //lower limit for tlimit |
---|
| 608 | G4double rat = currentKinEnergy/MeV ; |
---|
| 609 | rat = 1.e-3/(rat*(10.+rat)) ; |
---|
| 610 | tlimitmin = 10.*lambda0*rat; |
---|
| 611 | if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix; |
---|
| 612 | } |
---|
| 613 | //step limit |
---|
| 614 | tlimit = fr*rangeinit; |
---|
| 615 | |
---|
| 616 | if(tlimit < facsafety*presafety) |
---|
| 617 | tlimit = facsafety*presafety; |
---|
| 618 | |
---|
| 619 | //lower limit for tlimit |
---|
| 620 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
| 621 | |
---|
| 622 | if(tPathLength > tlimit) tPathLength = tlimit; |
---|
| 623 | } |
---|
| 624 | |
---|
| 625 | // version similar to 7.1 (needed for some experiments) |
---|
| 626 | else |
---|
| 627 | { |
---|
| 628 | if (stepStatus == fGeomBoundary) |
---|
| 629 | { |
---|
| 630 | if (currentRange > lambda0) tlimit = facrange*currentRange; |
---|
| 631 | else tlimit = facrange*lambda0; |
---|
| 632 | |
---|
| 633 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
| 634 | if(tPathLength > tlimit) tPathLength = tlimit; |
---|
| 635 | } |
---|
| 636 | } |
---|
| 637 | // G4cout << "tPathLength= " << tPathLength << " geomlimit= " << geomlimit |
---|
| 638 | // << " currentMinimalStep= " << currentMinimalStep << G4endl; |
---|
| 639 | return tPathLength ; |
---|
| 640 | } |
---|
| 641 | |
---|
| 642 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 643 | |
---|
| 644 | G4double G4UrbanMscModel92::ComputeGeomPathLength(G4double) |
---|
| 645 | { |
---|
| 646 | lambdaeff = lambda0; |
---|
| 647 | par1 = -1. ; |
---|
| 648 | par2 = par3 = 0. ; |
---|
| 649 | |
---|
| 650 | // do the true -> geom transformation |
---|
| 651 | zPathLength = tPathLength; |
---|
| 652 | |
---|
| 653 | // z = t for very small tPathLength |
---|
| 654 | if(tPathLength < tlimitminfix) return zPathLength; |
---|
| 655 | |
---|
| 656 | // this correction needed to run MSC with eIoni and eBrem inactivated |
---|
| 657 | // and makes no harm for a normal run |
---|
| 658 | if(tPathLength > currentRange) |
---|
| 659 | tPathLength = currentRange ; |
---|
| 660 | |
---|
| 661 | G4double tau = tPathLength/lambda0 ; |
---|
| 662 | |
---|
| 663 | if ((tau <= tausmall) || insideskin) { |
---|
| 664 | zPathLength = tPathLength; |
---|
| 665 | if(zPathLength > lambda0) zPathLength = lambda0; |
---|
| 666 | return zPathLength; |
---|
| 667 | } |
---|
| 668 | |
---|
| 669 | G4double zmean = tPathLength; |
---|
| 670 | if (tPathLength < currentRange*dtrl) { |
---|
| 671 | if(tau < taulim) zmean = tPathLength*(1.-0.5*tau) ; |
---|
| 672 | else zmean = lambda0*(1.-exp(-tau)); |
---|
| 673 | } else if(currentKinEnergy < mass) { |
---|
| 674 | par1 = 1./currentRange ; |
---|
| 675 | par2 = 1./(par1*lambda0) ; |
---|
| 676 | par3 = 1.+par2 ; |
---|
| 677 | if(tPathLength < currentRange) |
---|
| 678 | zmean = (1.-exp(par3*log(1.-tPathLength/currentRange)))/(par1*par3) ; |
---|
| 679 | else |
---|
| 680 | zmean = 1./(par1*par3) ; |
---|
| 681 | } else { |
---|
| 682 | G4double T1 = theManager->GetEnergy(particle,currentRange-tPathLength,couple); |
---|
| 683 | G4double lambda1 = GetLambda(T1); |
---|
| 684 | |
---|
| 685 | par1 = (lambda0-lambda1)/(lambda0*tPathLength) ; |
---|
| 686 | par2 = 1./(par1*lambda0) ; |
---|
| 687 | par3 = 1.+par2 ; |
---|
| 688 | zmean = (1.-exp(par3*log(lambda1/lambda0)))/(par1*par3) ; |
---|
| 689 | } |
---|
| 690 | |
---|
| 691 | zPathLength = zmean ; |
---|
| 692 | |
---|
| 693 | // sample z |
---|
| 694 | if(samplez) |
---|
| 695 | { |
---|
| 696 | const G4double ztmax = 0.99 ; |
---|
| 697 | G4double zt = zmean/tPathLength ; |
---|
| 698 | |
---|
| 699 | if (tPathLength > stepmin && zt < ztmax) |
---|
| 700 | { |
---|
| 701 | G4double u,cz1; |
---|
| 702 | if(zt >= third) |
---|
| 703 | { |
---|
| 704 | G4double cz = 0.5*(3.*zt-1.)/(1.-zt) ; |
---|
| 705 | cz1 = 1.+cz ; |
---|
| 706 | G4double u0 = cz/cz1 ; |
---|
| 707 | G4double grej ; |
---|
| 708 | do { |
---|
| 709 | u = exp(log(G4UniformRand())/cz1) ; |
---|
| 710 | grej = exp(cz*log(u/u0))*(1.-u)/(1.-u0) ; |
---|
| 711 | } while (grej < G4UniformRand()) ; |
---|
| 712 | } |
---|
| 713 | else |
---|
| 714 | { |
---|
| 715 | cz1 = 1./zt-1.; |
---|
| 716 | u = 1.-exp(log(G4UniformRand())/cz1) ; |
---|
| 717 | } |
---|
| 718 | zPathLength = tPathLength*u ; |
---|
| 719 | } |
---|
| 720 | } |
---|
| 721 | |
---|
| 722 | if(zPathLength > lambda0) zPathLength = lambda0; |
---|
| 723 | |
---|
| 724 | return zPathLength; |
---|
| 725 | } |
---|
| 726 | |
---|
| 727 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 728 | |
---|
| 729 | G4double G4UrbanMscModel92::ComputeTrueStepLength(G4double geomStepLength) |
---|
| 730 | { |
---|
| 731 | // step defined other than transportation |
---|
| 732 | if(geomStepLength == zPathLength && tPathLength <= currentRange) |
---|
| 733 | return tPathLength; |
---|
| 734 | |
---|
| 735 | // t = z for very small step |
---|
| 736 | zPathLength = geomStepLength; |
---|
| 737 | tPathLength = geomStepLength; |
---|
| 738 | if(geomStepLength < tlimitminfix) return tPathLength; |
---|
| 739 | |
---|
| 740 | // recalculation |
---|
| 741 | if((geomStepLength > lambda0*tausmall) && !insideskin) |
---|
| 742 | { |
---|
| 743 | if(par1 < 0.) |
---|
| 744 | tPathLength = -lambda0*log(1.-geomStepLength/lambda0) ; |
---|
| 745 | else |
---|
| 746 | { |
---|
| 747 | if(par1*par3*geomStepLength < 1.) |
---|
| 748 | tPathLength = (1.-exp(log(1.-par1*par3*geomStepLength)/par3))/par1 ; |
---|
| 749 | else |
---|
| 750 | tPathLength = currentRange; |
---|
| 751 | } |
---|
| 752 | } |
---|
| 753 | if(tPathLength < geomStepLength) tPathLength = geomStepLength; |
---|
| 754 | |
---|
| 755 | return tPathLength; |
---|
| 756 | } |
---|
| 757 | |
---|
| 758 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 759 | |
---|
| 760 | G4double G4UrbanMscModel92::ComputeTheta0(G4double trueStepLength, |
---|
| 761 | G4double KineticEnergy) |
---|
| 762 | { |
---|
| 763 | // for all particles take the width of the central part |
---|
| 764 | // from a parametrization similar to the Highland formula |
---|
| 765 | // ( Highland formula: Particle Physics Booklet, July 2002, eq. 26.10) |
---|
| 766 | const G4double c_highland = 13.6*MeV ; |
---|
| 767 | G4double betacp = sqrt(currentKinEnergy*(currentKinEnergy+2.*mass)* |
---|
| 768 | KineticEnergy*(KineticEnergy+2.*mass)/ |
---|
| 769 | ((currentKinEnergy+mass)*(KineticEnergy+mass))); |
---|
| 770 | y = trueStepLength/currentRadLength; |
---|
| 771 | G4double theta0 = c_highland*std::abs(charge)*sqrt(y)/betacp; |
---|
| 772 | y = log(y); |
---|
| 773 | // correction factor from e-/proton scattering data |
---|
| 774 | G4double corr = coeffth1+coeffth2*y; |
---|
| 775 | if(y < -6.5) corr -= 0.011*(6.5+y); |
---|
| 776 | theta0 *= corr ; |
---|
| 777 | |
---|
| 778 | return theta0; |
---|
| 779 | } |
---|
| 780 | |
---|
| 781 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 782 | |
---|
| 783 | void G4UrbanMscModel92::SampleScattering(const G4DynamicParticle* dynParticle, |
---|
| 784 | G4double safety) |
---|
| 785 | { |
---|
| 786 | G4double kineticEnergy = dynParticle->GetKineticEnergy(); |
---|
| 787 | |
---|
| 788 | if((kineticEnergy <= 0.0) || (tPathLength <= tlimitminfix) || |
---|
| 789 | (tPathLength/tausmall < lambda0)) return; |
---|
| 790 | |
---|
| 791 | G4double cth = SampleCosineTheta(tPathLength,kineticEnergy); |
---|
| 792 | |
---|
| 793 | // protection against 'bad' cth values |
---|
| 794 | if(std::abs(cth) > 1.) return; |
---|
| 795 | |
---|
| 796 | G4double sth = sqrt((1.0 - cth)*(1.0 + cth)); |
---|
| 797 | G4double phi = twopi*G4UniformRand(); |
---|
| 798 | G4double dirx = sth*cos(phi); |
---|
| 799 | G4double diry = sth*sin(phi); |
---|
| 800 | |
---|
| 801 | G4ThreeVector oldDirection = dynParticle->GetMomentumDirection(); |
---|
| 802 | G4ThreeVector newDirection(dirx,diry,cth); |
---|
| 803 | newDirection.rotateUz(oldDirection); |
---|
| 804 | fParticleChange->ProposeMomentumDirection(newDirection); |
---|
| 805 | |
---|
| 806 | if (latDisplasment && safety > tlimitminfix) { |
---|
| 807 | |
---|
| 808 | G4double r = SampleDisplacement(); |
---|
| 809 | /* |
---|
| 810 | G4cout << "G4UrbanMscModel92::SampleSecondaries: e(MeV)= " << kineticEnergy |
---|
| 811 | << " sinTheta= " << sth << " r(mm)= " << r |
---|
| 812 | << " trueStep(mm)= " << tPathLength |
---|
| 813 | << " geomStep(mm)= " << zPathLength |
---|
| 814 | << G4endl; |
---|
| 815 | */ |
---|
| 816 | if(r > 0.) |
---|
| 817 | { |
---|
| 818 | G4double latcorr = LatCorrelation(); |
---|
| 819 | if(latcorr > r) latcorr = r; |
---|
| 820 | |
---|
| 821 | // sample direction of lateral displacement |
---|
| 822 | // compute it from the lateral correlation |
---|
| 823 | G4double Phi = 0.; |
---|
| 824 | if(std::abs(r*sth) < latcorr) |
---|
| 825 | Phi = twopi*G4UniformRand(); |
---|
| 826 | else |
---|
| 827 | { |
---|
| 828 | G4double psi = std::acos(latcorr/(r*sth)); |
---|
| 829 | if(G4UniformRand() < 0.5) |
---|
| 830 | Phi = phi+psi; |
---|
| 831 | else |
---|
| 832 | Phi = phi-psi; |
---|
| 833 | } |
---|
| 834 | |
---|
| 835 | dirx = std::cos(Phi); |
---|
| 836 | diry = std::sin(Phi); |
---|
| 837 | |
---|
| 838 | G4ThreeVector latDirection(dirx,diry,0.0); |
---|
| 839 | latDirection.rotateUz(oldDirection); |
---|
| 840 | |
---|
| 841 | ComputeDisplacement(fParticleChange, latDirection, r, safety); |
---|
| 842 | } |
---|
| 843 | } |
---|
| 844 | } |
---|
| 845 | |
---|
| 846 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 847 | |
---|
| 848 | G4double G4UrbanMscModel92::SampleCosineTheta(G4double trueStepLength, |
---|
| 849 | G4double KineticEnergy) |
---|
| 850 | { |
---|
| 851 | G4double cth = 1. ; |
---|
| 852 | G4double tau = trueStepLength/lambda0 ; |
---|
| 853 | |
---|
| 854 | Zeff = couple->GetMaterial()->GetTotNbOfElectPerVolume()/ |
---|
| 855 | couple->GetMaterial()->GetTotNbOfAtomsPerVolume() ; |
---|
| 856 | |
---|
| 857 | if(Zold != Zeff) |
---|
| 858 | UpdateCache(); |
---|
| 859 | |
---|
| 860 | if(insideskin) |
---|
| 861 | { |
---|
| 862 | //no scattering, single or plural scattering |
---|
| 863 | G4double mean = trueStepLength/stepmin ; |
---|
| 864 | |
---|
| 865 | G4int n = G4Poisson(mean); |
---|
| 866 | if(n > 0) |
---|
| 867 | { |
---|
| 868 | //screening (Moliere-Bethe) |
---|
| 869 | G4double mom2 = KineticEnergy*(2.*mass+KineticEnergy); |
---|
| 870 | G4double beta2 = mom2/((KineticEnergy+mass)*(KineticEnergy+mass)); |
---|
| 871 | G4double ascr = scr1/mom2; |
---|
| 872 | ascr *= 1.13+scr2/beta2; |
---|
| 873 | G4double ascr1 = 1.+2.*ascr; |
---|
| 874 | G4double bp1=ascr1+1.; |
---|
| 875 | G4double bm1=ascr1-1.; |
---|
| 876 | |
---|
| 877 | // single scattering from screened Rutherford x-section |
---|
| 878 | G4double ct,st,phi; |
---|
| 879 | G4double sx=0.,sy=0.,sz=0.; |
---|
| 880 | for(G4int i=1; i<=n; i++) |
---|
| 881 | { |
---|
| 882 | ct = ascr1-bp1*bm1/(2.*G4UniformRand()+bm1); |
---|
| 883 | if(ct < -1.) ct = -1.; |
---|
| 884 | if(ct > 1.) ct = 1.; |
---|
| 885 | st = sqrt(1.-ct*ct); |
---|
| 886 | phi = twopi*G4UniformRand(); |
---|
| 887 | sx += st*cos(phi); |
---|
| 888 | sy += st*sin(phi); |
---|
| 889 | sz += ct; |
---|
| 890 | } |
---|
| 891 | cth = sz/sqrt(sx*sx+sy*sy+sz*sz); |
---|
| 892 | } |
---|
| 893 | } |
---|
| 894 | else |
---|
| 895 | { |
---|
| 896 | if(trueStepLength >= currentRange*dtrl) |
---|
| 897 | { |
---|
| 898 | if(par1*trueStepLength < 1.) |
---|
| 899 | tau = -par2*log(1.-par1*trueStepLength) ; |
---|
| 900 | // for the case if ioni/brems are inactivated |
---|
| 901 | // see the corresponding condition in ComputeGeomPathLength |
---|
| 902 | else if(1.-KineticEnergy/currentKinEnergy > taulim) |
---|
| 903 | tau = taubig ; |
---|
| 904 | } |
---|
| 905 | currentTau = tau ; |
---|
| 906 | lambdaeff = trueStepLength/currentTau; |
---|
| 907 | currentRadLength = couple->GetMaterial()->GetRadlen(); |
---|
| 908 | |
---|
| 909 | if (tau >= taubig) cth = -1.+2.*G4UniformRand(); |
---|
| 910 | else if (tau >= tausmall) |
---|
| 911 | { |
---|
| 912 | G4double xsi = 3.0; |
---|
| 913 | G4double x0 = 1.; |
---|
| 914 | G4double a = 1., ea = 0., eaa = 1.; |
---|
| 915 | G4double b=2.,b1=3.,bx=1.,eb1=3.,ebx=1.; |
---|
| 916 | G4double prob = 1. , qprob = 1. ; |
---|
| 917 | G4double xmean1 = 1., xmean2 = 0.; |
---|
| 918 | G4double xmeanth = exp(-tau); |
---|
| 919 | G4double x2meanth = (1.+2.*exp(-2.5*tau))/3.; |
---|
| 920 | |
---|
| 921 | G4double relloss = 1.-KineticEnergy/currentKinEnergy; |
---|
| 922 | if(relloss > rellossmax) |
---|
| 923 | return SimpleScattering(xmeanth,x2meanth); |
---|
| 924 | |
---|
| 925 | G4double theta0 = ComputeTheta0(trueStepLength,KineticEnergy); |
---|
| 926 | |
---|
| 927 | // protection for very small angles |
---|
| 928 | if(theta0 < tausmall) return cth; |
---|
| 929 | |
---|
| 930 | if(theta0 > theta0max) |
---|
| 931 | return SimpleScattering(xmeanth,x2meanth); |
---|
| 932 | G4double sth = sin(0.5*theta0); |
---|
| 933 | a = 0.25/(sth*sth); |
---|
| 934 | |
---|
| 935 | ea = exp(-xsi); |
---|
| 936 | eaa = 1.-ea ; |
---|
| 937 | xmean1 = 1.-(1.-(1.+xsi)*ea)/(a*eaa); |
---|
| 938 | x0 = 1.-xsi/a; |
---|
| 939 | |
---|
| 940 | if(xmean1 <= 0.999*xmeanth) |
---|
| 941 | return SimpleScattering(xmeanth,x2meanth); |
---|
| 942 | |
---|
| 943 | // from MUSCAT H,Be,Fe data |
---|
| 944 | G4double c = coeffc1; |
---|
| 945 | if(y > -13.5) |
---|
| 946 | c += coeffc2*exp(3.*log(y+13.5)); |
---|
| 947 | |
---|
| 948 | if(abs(c-3.) < 0.001) c = 3.001; |
---|
| 949 | if(abs(c-2.) < 0.001) c = 2.001; |
---|
| 950 | |
---|
| 951 | G4double c1 = c-1.; |
---|
| 952 | |
---|
| 953 | //from continuity of derivatives |
---|
| 954 | b = 1.+(c-xsi)/a; |
---|
| 955 | |
---|
| 956 | b1 = b+1.; |
---|
| 957 | bx = c/a; |
---|
| 958 | eb1 = exp(c1*log(b1)); |
---|
| 959 | ebx = exp(c1*log(bx)); |
---|
| 960 | |
---|
| 961 | xmean2 = (x0*eb1+ebx-(eb1*bx-b1*ebx)/(c-2.))/(eb1-ebx); |
---|
| 962 | |
---|
| 963 | G4double f1x0 = a*ea/eaa; |
---|
| 964 | G4double f2x0 = c1*eb1/(bx*(eb1-ebx)); |
---|
| 965 | prob = f2x0/(f1x0+f2x0); |
---|
| 966 | |
---|
| 967 | qprob = xmeanth/(prob*xmean1+(1.-prob)*xmean2); |
---|
| 968 | |
---|
| 969 | // sampling of costheta |
---|
| 970 | if(G4UniformRand() < qprob) |
---|
| 971 | { |
---|
| 972 | if(G4UniformRand() < prob) |
---|
| 973 | cth = 1.+log(ea+G4UniformRand()*eaa)/a ; |
---|
| 974 | else |
---|
| 975 | cth = b-b1*bx/exp(log(ebx+(eb1-ebx)*G4UniformRand())/c1) ; |
---|
| 976 | } |
---|
| 977 | else |
---|
| 978 | cth = -1.+2.*G4UniformRand(); |
---|
| 979 | } |
---|
| 980 | } |
---|
| 981 | return cth ; |
---|
| 982 | } |
---|
| 983 | |
---|
| 984 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 985 | |
---|
| 986 | G4double G4UrbanMscModel92::SimpleScattering(G4double xmeanth,G4double x2meanth) |
---|
| 987 | { |
---|
| 988 | // 'large angle scattering' |
---|
| 989 | // 2 model functions with correct xmean and x2mean |
---|
| 990 | G4double a = (2.*xmeanth+9.*x2meanth-3.)/(2.*xmeanth-3.*x2meanth+1.); |
---|
| 991 | G4double prob = (a+2.)*xmeanth/a; |
---|
| 992 | |
---|
| 993 | // sampling |
---|
| 994 | G4double cth = 1.; |
---|
| 995 | if(G4UniformRand() < prob) |
---|
| 996 | cth = -1.+2.*exp(log(G4UniformRand())/(a+1.)); |
---|
| 997 | else |
---|
| 998 | cth = -1.+2.*G4UniformRand(); |
---|
| 999 | return cth; |
---|
| 1000 | } |
---|
| 1001 | |
---|
| 1002 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 1003 | |
---|
| 1004 | G4double G4UrbanMscModel92::SampleDisplacement() |
---|
| 1005 | { |
---|
| 1006 | const G4double kappa = 2.5; |
---|
| 1007 | const G4double kappapl1 = kappa+1.; |
---|
| 1008 | const G4double kappami1 = kappa-1.; |
---|
| 1009 | G4double rmean = 0.0; |
---|
| 1010 | if ((currentTau >= tausmall) && !insideskin) { |
---|
| 1011 | if (currentTau < taulim) { |
---|
| 1012 | rmean = kappa*currentTau*currentTau*currentTau* |
---|
| 1013 | (1.-kappapl1*currentTau*0.25)/6. ; |
---|
| 1014 | |
---|
| 1015 | } else { |
---|
| 1016 | G4double etau = 0.0; |
---|
| 1017 | if (currentTau<taubig) etau = exp(-currentTau); |
---|
| 1018 | rmean = -kappa*currentTau; |
---|
| 1019 | rmean = -exp(rmean)/(kappa*kappami1); |
---|
| 1020 | rmean += currentTau-kappapl1/kappa+kappa*etau/kappami1; |
---|
| 1021 | } |
---|
| 1022 | if (rmean>0.) rmean = 2.*lambdaeff*sqrt(rmean/3.0); |
---|
| 1023 | else rmean = 0.; |
---|
| 1024 | } |
---|
| 1025 | |
---|
| 1026 | // protection against z > t ........................... |
---|
| 1027 | if(rmean > 0.) { |
---|
| 1028 | G4double zt = (tPathLength-zPathLength)*(tPathLength+zPathLength); |
---|
| 1029 | if(zt <= 0.) |
---|
| 1030 | rmean = 0.; |
---|
| 1031 | else if(rmean*rmean > zt) |
---|
| 1032 | rmean = sqrt(zt); |
---|
| 1033 | } |
---|
| 1034 | return rmean; |
---|
| 1035 | } |
---|
| 1036 | |
---|
| 1037 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 1038 | |
---|
| 1039 | G4double G4UrbanMscModel92::LatCorrelation() |
---|
| 1040 | { |
---|
| 1041 | const G4double kappa = 2.5; |
---|
| 1042 | const G4double kappami1 = kappa-1.; |
---|
| 1043 | |
---|
| 1044 | G4double latcorr = 0.; |
---|
| 1045 | if((currentTau >= tausmall) && !insideskin) |
---|
| 1046 | { |
---|
| 1047 | if(currentTau < taulim) |
---|
| 1048 | latcorr = lambdaeff*kappa*currentTau*currentTau* |
---|
| 1049 | (1.-(kappa+1.)*currentTau/3.)/3.; |
---|
| 1050 | else |
---|
| 1051 | { |
---|
| 1052 | G4double etau = 0.; |
---|
| 1053 | if(currentTau < taubig) etau = exp(-currentTau); |
---|
| 1054 | latcorr = -kappa*currentTau; |
---|
| 1055 | latcorr = exp(latcorr)/kappami1; |
---|
| 1056 | latcorr += 1.-kappa*etau/kappami1 ; |
---|
| 1057 | latcorr *= 2.*lambdaeff/3. ; |
---|
| 1058 | } |
---|
| 1059 | } |
---|
| 1060 | |
---|
| 1061 | return latcorr; |
---|
| 1062 | } |
---|
| 1063 | |
---|
| 1064 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|