[819] | 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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[1055] | 27 | // $Id: G4UrbanMscModel.cc,v 1.90 2009/04/29 13:30:22 vnivanch Exp $ |
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| 28 | // GEANT4 tag $Name: geant4-09-03-beta-cand-01 $ |
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| 29 | // |
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[819] | 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: G4UrbanMscModel |
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| 36 | // |
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| 37 | // Author: Laszlo Urban |
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| 38 | // |
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[1055] | 39 | // Creation date: 06.03.2008 |
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[819] | 40 | // |
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| 41 | // Modifications: |
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| 42 | // |
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[1055] | 43 | // 06-03-2008 starting point : G4UrbanMscModel2 = G4UrbanMscModel 9.1 ref 02 |
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[819] | 44 | // |
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[1055] | 45 | // 13-03-08 Bug in SampleScattering (which caused lateral asymmetry) fixed |
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| 46 | // (L.Urban) |
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[819] | 47 | // |
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[1055] | 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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[819] | 51 | // |
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[1055] | 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 | // 28-04-09 move G4UrbanMscModel2 from the g49.2 to G4UrbanMscModel. |
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| 88 | // now it is frozen (V.Ivanchenk0) |
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[819] | 89 | |
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| 90 | // Class Description: |
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| 91 | // |
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| 92 | // Implementation of the model of multiple scattering based on |
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| 93 | // H.W.Lewis Phys Rev 78 (1950) 526 and others |
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| 94 | |
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| 95 | // ------------------------------------------------------------------- |
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[1055] | 96 | // In its present form the model can be used for simulation |
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| 97 | // of the e-/e+, muon and charged hadron multiple scattering |
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[819] | 98 | // |
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| 99 | |
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| 100 | |
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| 101 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 102 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 103 | |
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| 104 | #include "G4UrbanMscModel.hh" |
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| 105 | #include "Randomize.hh" |
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| 106 | #include "G4Electron.hh" |
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| 107 | #include "G4LossTableManager.hh" |
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| 108 | #include "G4ParticleChangeForMSC.hh" |
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| 109 | |
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| 110 | #include "G4Poisson.hh" |
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[1055] | 111 | #include "globals.hh" |
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[819] | 112 | |
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| 113 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 114 | |
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| 115 | using namespace std; |
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| 116 | |
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[961] | 117 | G4UrbanMscModel::G4UrbanMscModel(const G4String& nam) |
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| 118 | : G4VMscModel(nam), |
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[819] | 119 | isInitialized(false) |
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| 120 | { |
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[1055] | 121 | masslimite = 0.6*MeV; |
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| 122 | lambdalimit = 1.*mm; |
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| 123 | fr = 0.02; |
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| 124 | facsafety = 0.3; |
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[819] | 125 | taubig = 8.0; |
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| 126 | tausmall = 1.e-16; |
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| 127 | taulim = 1.e-6; |
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| 128 | currentTau = taulim; |
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| 129 | tlimitminfix = 1.e-6*mm; |
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| 130 | stepmin = tlimitminfix; |
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| 131 | smallstep = 1.e10; |
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| 132 | currentRange = 0. ; |
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[1055] | 133 | rangeinit = 0.; |
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[819] | 134 | tlimit = 1.e10*mm; |
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| 135 | tlimitmin = 10.*tlimitminfix; |
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[1055] | 136 | tgeom = 1.e50*mm; |
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[819] | 137 | geombig = 1.e50*mm; |
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| 138 | geommin = 1.e-3*mm; |
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| 139 | geomlimit = geombig; |
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| 140 | presafety = 0.*mm; |
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[1055] | 141 | |
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| 142 | y = 0.; |
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| 143 | |
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| 144 | Zold = 0.; |
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[819] | 145 | Zeff = 1.; |
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[1055] | 146 | Z2 = 1.; |
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| 147 | Z23 = 1.; |
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| 148 | lnZ = 0.; |
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| 149 | coeffth1 = 0.; |
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| 150 | coeffth2 = 0.; |
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| 151 | coeffc1 = 0.; |
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| 152 | coeffc2 = 0.; |
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| 153 | scr1ini = fine_structure_const*fine_structure_const* |
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| 154 | electron_mass_c2*electron_mass_c2/(0.885*0.885*4.*pi); |
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| 155 | scr2ini = 3.76*fine_structure_const*fine_structure_const; |
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| 156 | scr1 = 0.; |
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| 157 | scr2 = 0.; |
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| 158 | |
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| 159 | theta0max = pi/6.; |
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| 160 | rellossmax = 0.50; |
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| 161 | third = 1./3.; |
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[819] | 162 | particle = 0; |
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| 163 | theManager = G4LossTableManager::Instance(); |
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| 164 | inside = false; |
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| 165 | insideskin = false; |
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| 166 | |
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| 167 | } |
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| 168 | |
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| 169 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 170 | |
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| 171 | G4UrbanMscModel::~G4UrbanMscModel() |
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| 172 | {} |
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| 173 | |
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| 174 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 175 | |
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| 176 | void G4UrbanMscModel::Initialise(const G4ParticleDefinition* p, |
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[1055] | 177 | const G4DataVector&) |
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[819] | 178 | { |
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| 179 | skindepth = skin*stepmin; |
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| 180 | if(isInitialized) return; |
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| 181 | // set values of some data members |
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| 182 | SetParticle(p); |
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| 183 | |
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[1055] | 184 | fParticleChange = GetParticleChangeForMSC(); |
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| 185 | InitialiseSafetyHelper(); |
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[819] | 186 | |
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| 187 | isInitialized = true; |
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| 188 | } |
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| 189 | |
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| 190 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 191 | |
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| 192 | G4double G4UrbanMscModel::ComputeCrossSectionPerAtom( |
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| 193 | const G4ParticleDefinition* part, |
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| 194 | G4double KineticEnergy, |
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| 195 | G4double AtomicNumber,G4double, |
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| 196 | G4double, G4double) |
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| 197 | { |
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| 198 | const G4double sigmafactor = twopi*classic_electr_radius*classic_electr_radius; |
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| 199 | const G4double epsfactor = 2.*electron_mass_c2*electron_mass_c2* |
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| 200 | Bohr_radius*Bohr_radius/(hbarc*hbarc); |
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| 201 | const G4double epsmin = 1.e-4 , epsmax = 1.e10; |
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| 202 | |
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| 203 | const G4double Zdat[15] = { 4., 6., 13., 20., 26., 29., 32., 38., 47., |
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| 204 | 50., 56., 64., 74., 79., 82. }; |
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| 205 | |
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| 206 | const G4double Tdat[22] = { 100*eV, 200*eV, 400*eV, 700*eV, |
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| 207 | 1*keV, 2*keV, 4*keV, 7*keV, |
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| 208 | 10*keV, 20*keV, 40*keV, 70*keV, |
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| 209 | 100*keV, 200*keV, 400*keV, 700*keV, |
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| 210 | 1*MeV, 2*MeV, 4*MeV, 7*MeV, |
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| 211 | 10*MeV, 20*MeV}; |
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| 212 | |
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| 213 | // corr. factors for e-/e+ lambda for T <= Tlim |
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| 214 | G4double celectron[15][22] = |
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| 215 | {{1.125,1.072,1.051,1.047,1.047,1.050,1.052,1.054, |
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| 216 | 1.054,1.057,1.062,1.069,1.075,1.090,1.105,1.111, |
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| 217 | 1.112,1.108,1.100,1.093,1.089,1.087 }, |
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| 218 | {1.408,1.246,1.143,1.096,1.077,1.059,1.053,1.051, |
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| 219 | 1.052,1.053,1.058,1.065,1.072,1.087,1.101,1.108, |
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| 220 | 1.109,1.105,1.097,1.090,1.086,1.082 }, |
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| 221 | {2.833,2.268,1.861,1.612,1.486,1.309,1.204,1.156, |
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| 222 | 1.136,1.114,1.106,1.106,1.109,1.119,1.129,1.132, |
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| 223 | 1.131,1.124,1.113,1.104,1.099,1.098 }, |
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| 224 | {3.879,3.016,2.380,2.007,1.818,1.535,1.340,1.236, |
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| 225 | 1.190,1.133,1.107,1.099,1.098,1.103,1.110,1.113, |
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| 226 | 1.112,1.105,1.096,1.089,1.085,1.098 }, |
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| 227 | {6.937,4.330,2.886,2.256,1.987,1.628,1.395,1.265, |
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| 228 | 1.203,1.122,1.080,1.065,1.061,1.063,1.070,1.073, |
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| 229 | 1.073,1.070,1.064,1.059,1.056,1.056 }, |
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| 230 | {9.616,5.708,3.424,2.551,2.204,1.762,1.485,1.330, |
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| 231 | 1.256,1.155,1.099,1.077,1.070,1.068,1.072,1.074, |
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| 232 | 1.074,1.070,1.063,1.059,1.056,1.052 }, |
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| 233 | {11.72,6.364,3.811,2.806,2.401,1.884,1.564,1.386, |
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| 234 | 1.300,1.180,1.112,1.082,1.073,1.066,1.068,1.069, |
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| 235 | 1.068,1.064,1.059,1.054,1.051,1.050 }, |
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| 236 | {18.08,8.601,4.569,3.183,2.662,2.025,1.646,1.439, |
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| 237 | 1.339,1.195,1.108,1.068,1.053,1.040,1.039,1.039, |
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| 238 | 1.039,1.037,1.034,1.031,1.030,1.036 }, |
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| 239 | {18.22,10.48,5.333,3.713,3.115,2.367,1.898,1.631, |
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| 240 | 1.498,1.301,1.171,1.105,1.077,1.048,1.036,1.033, |
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| 241 | 1.031,1.028,1.024,1.022,1.021,1.024 }, |
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| 242 | {14.14,10.65,5.710,3.929,3.266,2.453,1.951,1.669, |
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| 243 | 1.528,1.319,1.178,1.106,1.075,1.040,1.027,1.022, |
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| 244 | 1.020,1.017,1.015,1.013,1.013,1.020 }, |
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| 245 | {14.11,11.73,6.312,4.240,3.478,2.566,2.022,1.720, |
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| 246 | 1.569,1.342,1.186,1.102,1.065,1.022,1.003,0.997, |
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| 247 | 0.995,0.993,0.993,0.993,0.993,1.011 }, |
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| 248 | {22.76,20.01,8.835,5.287,4.144,2.901,2.219,1.855, |
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| 249 | 1.677,1.410,1.224,1.121,1.073,1.014,0.986,0.976, |
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| 250 | 0.974,0.972,0.973,0.974,0.975,0.987 }, |
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| 251 | {50.77,40.85,14.13,7.184,5.284,3.435,2.520,2.059, |
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| 252 | 1.837,1.512,1.283,1.153,1.091,1.010,0.969,0.954, |
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| 253 | 0.950,0.947,0.949,0.952,0.954,0.963 }, |
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| 254 | {65.87,59.06,15.87,7.570,5.567,3.650,2.682,2.182, |
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| 255 | 1.939,1.579,1.325,1.178,1.108,1.014,0.965,0.947, |
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| 256 | 0.941,0.938,0.940,0.944,0.946,0.954 }, |
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| 257 | {55.60,47.34,15.92,7.810,5.755,3.767,2.760,2.239, |
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| 258 | 1.985,1.609,1.343,1.188,1.113,1.013,0.960,0.939, |
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| 259 | 0.933,0.930,0.933,0.936,0.939,0.949 }}; |
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| 260 | |
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| 261 | G4double cpositron[15][22] = { |
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| 262 | {2.589,2.044,1.658,1.446,1.347,1.217,1.144,1.110, |
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| 263 | 1.097,1.083,1.080,1.086,1.092,1.108,1.123,1.131, |
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| 264 | 1.131,1.126,1.117,1.108,1.103,1.100 }, |
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| 265 | {3.904,2.794,2.079,1.710,1.543,1.325,1.202,1.145, |
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| 266 | 1.122,1.096,1.089,1.092,1.098,1.114,1.130,1.137, |
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| 267 | 1.138,1.132,1.122,1.113,1.108,1.102 }, |
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| 268 | {7.970,6.080,4.442,3.398,2.872,2.127,1.672,1.451, |
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| 269 | 1.357,1.246,1.194,1.179,1.178,1.188,1.201,1.205, |
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| 270 | 1.203,1.190,1.173,1.159,1.151,1.145 }, |
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| 271 | {9.714,7.607,5.747,4.493,3.815,2.777,2.079,1.715, |
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| 272 | 1.553,1.353,1.253,1.219,1.211,1.214,1.225,1.228, |
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| 273 | 1.225,1.210,1.191,1.175,1.166,1.174 }, |
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| 274 | {17.97,12.95,8.628,6.065,4.849,3.222,2.275,1.820, |
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| 275 | 1.624,1.382,1.259,1.214,1.202,1.202,1.214,1.219, |
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| 276 | 1.217,1.203,1.184,1.169,1.160,1.151 }, |
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| 277 | {24.83,17.06,10.84,7.355,5.767,3.707,2.546,1.996, |
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| 278 | 1.759,1.465,1.311,1.252,1.234,1.228,1.238,1.241, |
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| 279 | 1.237,1.222,1.201,1.184,1.174,1.159 }, |
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| 280 | {23.26,17.15,11.52,8.049,6.375,4.114,2.792,2.155, |
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| 281 | 1.880,1.535,1.353,1.281,1.258,1.247,1.254,1.256, |
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| 282 | 1.252,1.234,1.212,1.194,1.183,1.170 }, |
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| 283 | {22.33,18.01,12.86,9.212,7.336,4.702,3.117,2.348, |
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| 284 | 2.015,1.602,1.385,1.297,1.268,1.251,1.256,1.258, |
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| 285 | 1.254,1.237,1.214,1.195,1.185,1.179 }, |
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| 286 | {33.91,24.13,15.71,10.80,8.507,5.467,3.692,2.808, |
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| 287 | 2.407,1.873,1.564,1.425,1.374,1.330,1.324,1.320, |
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| 288 | 1.312,1.288,1.258,1.235,1.221,1.205 }, |
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| 289 | {32.14,24.11,16.30,11.40,9.015,5.782,3.868,2.917, |
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| 290 | 2.490,1.925,1.596,1.447,1.391,1.342,1.332,1.327, |
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| 291 | 1.320,1.294,1.264,1.240,1.226,1.214 }, |
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| 292 | {29.51,24.07,17.19,12.28,9.766,6.238,4.112,3.066, |
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| 293 | 2.602,1.995,1.641,1.477,1.414,1.356,1.342,1.336, |
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| 294 | 1.328,1.302,1.270,1.245,1.231,1.233 }, |
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| 295 | {38.19,30.85,21.76,15.35,12.07,7.521,4.812,3.498, |
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| 296 | 2.926,2.188,1.763,1.563,1.484,1.405,1.382,1.371, |
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| 297 | 1.361,1.330,1.294,1.267,1.251,1.239 }, |
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| 298 | {49.71,39.80,27.96,19.63,15.36,9.407,5.863,4.155, |
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| 299 | 3.417,2.478,1.944,1.692,1.589,1.480,1.441,1.423, |
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| 300 | 1.409,1.372,1.330,1.298,1.280,1.258 }, |
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| 301 | {59.25,45.08,30.36,20.83,16.15,9.834,6.166,4.407, |
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| 302 | 3.641,2.648,2.064,1.779,1.661,1.531,1.482,1.459, |
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| 303 | 1.442,1.400,1.354,1.319,1.299,1.272 }, |
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| 304 | {56.38,44.29,30.50,21.18,16.51,10.11,6.354,4.542, |
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| 305 | 3.752,2.724,2.116,1.817,1.692,1.554,1.499,1.474, |
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| 306 | 1.456,1.412,1.364,1.328,1.307,1.282 }}; |
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| 307 | |
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| 308 | //data/corrections for T > Tlim |
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| 309 | G4double Tlim = 10.*MeV; |
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| 310 | G4double beta2lim = Tlim*(Tlim+2.*electron_mass_c2)/ |
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| 311 | ((Tlim+electron_mass_c2)*(Tlim+electron_mass_c2)); |
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| 312 | G4double bg2lim = Tlim*(Tlim+2.*electron_mass_c2)/ |
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| 313 | (electron_mass_c2*electron_mass_c2); |
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| 314 | |
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| 315 | G4double sig0[15] = {0.2672*barn, 0.5922*barn, 2.653*barn, 6.235*barn, |
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| 316 | 11.69*barn , 13.24*barn , 16.12*barn, 23.00*barn , |
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| 317 | 35.13*barn , 39.95*barn , 50.85*barn, 67.19*barn , |
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| 318 | 91.15*barn , 104.4*barn , 113.1*barn}; |
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| 319 | |
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| 320 | G4double hecorr[15] = {120.70, 117.50, 105.00, 92.92, 79.23, 74.510, 68.29, |
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| 321 | 57.39, 41.97, 36.14, 24.53, 10.21, -7.855, -16.84, |
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| 322 | -22.30}; |
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| 323 | |
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| 324 | G4double sigma; |
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| 325 | SetParticle(part); |
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| 326 | |
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| 327 | G4double Z23 = 2.*log(AtomicNumber)/3.; Z23 = exp(Z23); |
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| 328 | |
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| 329 | // correction if particle .ne. e-/e+ |
---|
| 330 | // compute equivalent kinetic energy |
---|
| 331 | // lambda depends on p*beta .... |
---|
| 332 | |
---|
| 333 | G4double eKineticEnergy = KineticEnergy; |
---|
| 334 | |
---|
[961] | 335 | if(mass > electron_mass_c2) |
---|
[819] | 336 | { |
---|
[1055] | 337 | G4double TAU = KineticEnergy/mass ; |
---|
| 338 | G4double c = mass*TAU*(TAU+2.)/(electron_mass_c2*(TAU+1.)) ; |
---|
| 339 | G4double w = c-2. ; |
---|
| 340 | G4double tau = 0.5*(w+sqrt(w*w+4.*c)) ; |
---|
| 341 | eKineticEnergy = electron_mass_c2*tau ; |
---|
[819] | 342 | } |
---|
| 343 | |
---|
| 344 | G4double eTotalEnergy = eKineticEnergy + electron_mass_c2 ; |
---|
| 345 | G4double beta2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2) |
---|
| 346 | /(eTotalEnergy*eTotalEnergy); |
---|
| 347 | G4double bg2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2) |
---|
| 348 | /(electron_mass_c2*electron_mass_c2); |
---|
| 349 | |
---|
| 350 | G4double eps = epsfactor*bg2/Z23; |
---|
| 351 | |
---|
| 352 | if (eps<epsmin) sigma = 2.*eps*eps; |
---|
| 353 | else if(eps<epsmax) sigma = log(1.+2.*eps)-2.*eps/(1.+2.*eps); |
---|
| 354 | else sigma = log(2.*eps)-1.+1./eps; |
---|
| 355 | |
---|
| 356 | sigma *= ChargeSquare*AtomicNumber*AtomicNumber/(beta2*bg2); |
---|
| 357 | |
---|
| 358 | // interpolate in AtomicNumber and beta2 |
---|
| 359 | G4double c1,c2,cc1,cc2,corr; |
---|
| 360 | |
---|
| 361 | // get bin number in Z |
---|
| 362 | G4int iZ = 14; |
---|
| 363 | while ((iZ>=0)&&(Zdat[iZ]>=AtomicNumber)) iZ -= 1; |
---|
| 364 | if (iZ==14) iZ = 13; |
---|
| 365 | if (iZ==-1) iZ = 0 ; |
---|
| 366 | |
---|
| 367 | G4double Z1 = Zdat[iZ]; |
---|
| 368 | G4double Z2 = Zdat[iZ+1]; |
---|
| 369 | G4double ratZ = (AtomicNumber-Z1)*(AtomicNumber+Z1)/ |
---|
| 370 | ((Z2-Z1)*(Z2+Z1)); |
---|
| 371 | |
---|
| 372 | if(eKineticEnergy <= Tlim) |
---|
| 373 | { |
---|
| 374 | // get bin number in T (beta2) |
---|
| 375 | G4int iT = 21; |
---|
| 376 | while ((iT>=0)&&(Tdat[iT]>=eKineticEnergy)) iT -= 1; |
---|
| 377 | if(iT==21) iT = 20; |
---|
| 378 | if(iT==-1) iT = 0 ; |
---|
| 379 | |
---|
| 380 | // calculate betasquare values |
---|
| 381 | G4double T = Tdat[iT], E = T + electron_mass_c2; |
---|
| 382 | G4double b2small = T*(E+electron_mass_c2)/(E*E); |
---|
| 383 | |
---|
| 384 | T = Tdat[iT+1]; E = T + electron_mass_c2; |
---|
| 385 | G4double b2big = T*(E+electron_mass_c2)/(E*E); |
---|
| 386 | G4double ratb2 = (beta2-b2small)/(b2big-b2small); |
---|
| 387 | |
---|
| 388 | if (charge < 0.) |
---|
| 389 | { |
---|
| 390 | c1 = celectron[iZ][iT]; |
---|
| 391 | c2 = celectron[iZ+1][iT]; |
---|
| 392 | cc1 = c1+ratZ*(c2-c1); |
---|
| 393 | |
---|
| 394 | c1 = celectron[iZ][iT+1]; |
---|
| 395 | c2 = celectron[iZ+1][iT+1]; |
---|
| 396 | cc2 = c1+ratZ*(c2-c1); |
---|
| 397 | |
---|
| 398 | corr = cc1+ratb2*(cc2-cc1); |
---|
| 399 | |
---|
| 400 | sigma *= sigmafactor/corr; |
---|
| 401 | } |
---|
| 402 | else |
---|
| 403 | { |
---|
| 404 | c1 = cpositron[iZ][iT]; |
---|
| 405 | c2 = cpositron[iZ+1][iT]; |
---|
| 406 | cc1 = c1+ratZ*(c2-c1); |
---|
| 407 | |
---|
| 408 | c1 = cpositron[iZ][iT+1]; |
---|
| 409 | c2 = cpositron[iZ+1][iT+1]; |
---|
| 410 | cc2 = c1+ratZ*(c2-c1); |
---|
| 411 | |
---|
| 412 | corr = cc1+ratb2*(cc2-cc1); |
---|
| 413 | |
---|
| 414 | sigma *= sigmafactor/corr; |
---|
| 415 | } |
---|
| 416 | } |
---|
| 417 | else |
---|
| 418 | { |
---|
| 419 | c1 = bg2lim*sig0[iZ]*(1.+hecorr[iZ]*(beta2-beta2lim))/bg2; |
---|
| 420 | c2 = bg2lim*sig0[iZ+1]*(1.+hecorr[iZ+1]*(beta2-beta2lim))/bg2; |
---|
| 421 | if((AtomicNumber >= Z1) && (AtomicNumber <= Z2)) |
---|
| 422 | sigma = c1+ratZ*(c2-c1) ; |
---|
| 423 | else if(AtomicNumber < Z1) |
---|
| 424 | sigma = AtomicNumber*AtomicNumber*c1/(Z1*Z1); |
---|
| 425 | else if(AtomicNumber > Z2) |
---|
| 426 | sigma = AtomicNumber*AtomicNumber*c2/(Z2*Z2); |
---|
| 427 | } |
---|
| 428 | return sigma; |
---|
| 429 | |
---|
| 430 | } |
---|
| 431 | |
---|
| 432 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 433 | |
---|
| 434 | G4double G4UrbanMscModel::ComputeTruePathLengthLimit( |
---|
| 435 | const G4Track& track, |
---|
| 436 | G4PhysicsTable* theTable, |
---|
| 437 | G4double currentMinimalStep) |
---|
| 438 | { |
---|
| 439 | tPathLength = currentMinimalStep; |
---|
[961] | 440 | G4StepPoint* sp = track.GetStep()->GetPreStepPoint(); |
---|
| 441 | G4StepStatus stepStatus = sp->GetStepStatus(); |
---|
[819] | 442 | |
---|
[1055] | 443 | const G4DynamicParticle* dp = track.GetDynamicParticle(); |
---|
| 444 | |
---|
[961] | 445 | if(stepStatus == fUndefined) { |
---|
[819] | 446 | inside = false; |
---|
| 447 | insideskin = false; |
---|
| 448 | tlimit = geombig; |
---|
| 449 | SetParticle( dp->GetDefinition() ); |
---|
| 450 | } |
---|
| 451 | |
---|
| 452 | theLambdaTable = theTable; |
---|
| 453 | couple = track.GetMaterialCutsCouple(); |
---|
| 454 | currentMaterialIndex = couple->GetIndex(); |
---|
| 455 | currentKinEnergy = dp->GetKineticEnergy(); |
---|
| 456 | currentRange = |
---|
| 457 | theManager->GetRangeFromRestricteDEDX(particle,currentKinEnergy,couple); |
---|
| 458 | lambda0 = GetLambda(currentKinEnergy); |
---|
| 459 | |
---|
| 460 | // stop here if small range particle |
---|
| 461 | if(inside) return tPathLength; |
---|
| 462 | |
---|
| 463 | if(tPathLength > currentRange) tPathLength = currentRange; |
---|
| 464 | |
---|
| 465 | presafety = sp->GetSafety(); |
---|
| 466 | |
---|
[1055] | 467 | // G4cout << "G4UrbanMscModel::ComputeTruePathLengthLimit tPathLength= " |
---|
| 468 | // <<tPathLength<<" safety= " << presafety |
---|
| 469 | // << " range= " <<currentRange<<G4endl; |
---|
[819] | 470 | |
---|
| 471 | // far from geometry boundary |
---|
| 472 | if(currentRange < presafety) |
---|
| 473 | { |
---|
| 474 | inside = true; |
---|
| 475 | return tPathLength; |
---|
| 476 | } |
---|
| 477 | |
---|
| 478 | // standard version |
---|
| 479 | // |
---|
| 480 | if (steppingAlgorithm == fUseDistanceToBoundary) |
---|
| 481 | { |
---|
| 482 | //compute geomlimit and presafety |
---|
[1055] | 483 | G4double geomlimit = ComputeGeomLimit(track, presafety, currentRange); |
---|
[819] | 484 | |
---|
[1055] | 485 | // is it far from boundary ? |
---|
| 486 | if(currentRange < presafety) |
---|
[819] | 487 | { |
---|
| 488 | inside = true; |
---|
| 489 | return tPathLength; |
---|
| 490 | } |
---|
| 491 | |
---|
| 492 | smallstep += 1.; |
---|
| 493 | insideskin = false; |
---|
| 494 | |
---|
[961] | 495 | if((stepStatus == fGeomBoundary) || (stepStatus == fUndefined)) |
---|
[819] | 496 | { |
---|
[1055] | 497 | rangeinit = currentRange; |
---|
[961] | 498 | if(stepStatus == fUndefined) smallstep = 1.e10; |
---|
[819] | 499 | else smallstep = 1.; |
---|
| 500 | |
---|
[1055] | 501 | // constraint from the geometry |
---|
[819] | 502 | if((geomlimit < geombig) && (geomlimit > geommin)) |
---|
| 503 | { |
---|
| 504 | if(stepStatus == fGeomBoundary) |
---|
| 505 | tgeom = geomlimit/facgeom; |
---|
| 506 | else |
---|
| 507 | tgeom = 2.*geomlimit/facgeom; |
---|
| 508 | } |
---|
[1055] | 509 | else |
---|
| 510 | tgeom = geombig; |
---|
[819] | 511 | |
---|
[1055] | 512 | //define stepmin here (it depends on lambda!) |
---|
| 513 | //rough estimation of lambda_elastic/lambda_transport |
---|
| 514 | G4double rat = currentKinEnergy/MeV ; |
---|
| 515 | rat = 1.e-3/(rat*(10.+rat)) ; |
---|
| 516 | //stepmin ~ lambda_elastic |
---|
| 517 | stepmin = rat*lambda0; |
---|
| 518 | skindepth = skin*stepmin; |
---|
[819] | 519 | |
---|
[1055] | 520 | //define tlimitmin |
---|
| 521 | tlimitmin = 10.*stepmin; |
---|
| 522 | if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix; |
---|
| 523 | |
---|
| 524 | } |
---|
| 525 | |
---|
| 526 | //step limit |
---|
| 527 | tlimit = facrange*rangeinit; |
---|
| 528 | if(tlimit < facsafety*presafety) |
---|
| 529 | tlimit = facsafety*presafety; |
---|
| 530 | |
---|
| 531 | //lower limit for tlimit |
---|
| 532 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
| 533 | |
---|
| 534 | if(tlimit > tgeom) tlimit = tgeom; |
---|
| 535 | |
---|
[819] | 536 | // G4cout << "tgeom= " << tgeom << " geomlimit= " << geomlimit |
---|
| 537 | // << " tlimit= " << tlimit << " presafety= " << presafety << G4endl; |
---|
| 538 | |
---|
| 539 | // shortcut |
---|
[1055] | 540 | if((tPathLength < tlimit) && (tPathLength < presafety) && |
---|
| 541 | (smallstep >= skin) && (tPathLength < geomlimit-0.999*skindepth)) |
---|
[819] | 542 | return tPathLength; |
---|
| 543 | |
---|
| 544 | // step reduction near to boundary |
---|
| 545 | if(smallstep < skin) |
---|
| 546 | { |
---|
[1055] | 547 | tlimit = stepmin; |
---|
[819] | 548 | insideskin = true; |
---|
| 549 | } |
---|
| 550 | else if(geomlimit < geombig) |
---|
| 551 | { |
---|
| 552 | if(geomlimit > skindepth) |
---|
| 553 | { |
---|
[1055] | 554 | if(tlimit > geomlimit-0.999*skindepth) |
---|
| 555 | tlimit = geomlimit-0.999*skindepth; |
---|
[819] | 556 | } |
---|
| 557 | else |
---|
| 558 | { |
---|
| 559 | insideskin = true; |
---|
[1055] | 560 | if(tlimit > stepmin) tlimit = stepmin; |
---|
[819] | 561 | } |
---|
| 562 | } |
---|
| 563 | |
---|
[1055] | 564 | if(tlimit < stepmin) tlimit = stepmin; |
---|
[819] | 565 | |
---|
[1055] | 566 | if(tPathLength > tlimit) tPathLength = tlimit ; |
---|
| 567 | |
---|
[819] | 568 | } |
---|
| 569 | // for 'normal' simulation with or without magnetic field |
---|
| 570 | // there no small step/single scattering at boundaries |
---|
| 571 | else if(steppingAlgorithm == fUseSafety) |
---|
| 572 | { |
---|
| 573 | // compute presafety again if presafety <= 0 and no boundary |
---|
| 574 | // i.e. when it is needed for optimization purposes |
---|
| 575 | if((stepStatus != fGeomBoundary) && (presafety < tlimitminfix)) |
---|
[1055] | 576 | presafety = ComputeSafety(sp->GetPosition(),tPathLength); |
---|
[819] | 577 | |
---|
| 578 | // is far from boundary |
---|
| 579 | if(currentRange < presafety) |
---|
| 580 | { |
---|
| 581 | inside = true; |
---|
| 582 | return tPathLength; |
---|
| 583 | } |
---|
| 584 | |
---|
[961] | 585 | if((stepStatus == fGeomBoundary) || (stepStatus == fUndefined)) |
---|
[1055] | 586 | { |
---|
| 587 | rangeinit = currentRange; |
---|
| 588 | fr = facrange; |
---|
| 589 | // 9.1 like stepping for e+/e- only (not for muons,hadrons) |
---|
| 590 | if(mass < masslimite) |
---|
| 591 | { |
---|
| 592 | if(lambda0 > currentRange) |
---|
| 593 | rangeinit = lambda0; |
---|
| 594 | if(lambda0 > lambdalimit) |
---|
| 595 | fr *= 0.75+0.25*lambda0/lambdalimit; |
---|
| 596 | } |
---|
[819] | 597 | |
---|
[1055] | 598 | //lower limit for tlimit |
---|
| 599 | G4double rat = currentKinEnergy/MeV ; |
---|
| 600 | rat = 1.e-3/(rat*(10.+rat)) ; |
---|
| 601 | tlimitmin = 10.*lambda0*rat; |
---|
| 602 | if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix; |
---|
| 603 | } |
---|
| 604 | //step limit |
---|
| 605 | tlimit = fr*rangeinit; |
---|
[819] | 606 | |
---|
[1055] | 607 | if(tlimit < facsafety*presafety) |
---|
| 608 | tlimit = facsafety*presafety; |
---|
[819] | 609 | |
---|
[1055] | 610 | //lower limit for tlimit |
---|
| 611 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
[819] | 612 | |
---|
| 613 | if(tPathLength > tlimit) tPathLength = tlimit; |
---|
| 614 | } |
---|
| 615 | |
---|
| 616 | // version similar to 7.1 (needed for some experiments) |
---|
| 617 | else |
---|
| 618 | { |
---|
| 619 | if (stepStatus == fGeomBoundary) |
---|
| 620 | { |
---|
| 621 | if (currentRange > lambda0) tlimit = facrange*currentRange; |
---|
| 622 | else tlimit = facrange*lambda0; |
---|
| 623 | |
---|
| 624 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
| 625 | if(tPathLength > tlimit) tPathLength = tlimit; |
---|
| 626 | } |
---|
| 627 | } |
---|
[1055] | 628 | // G4cout << "tPathLength= " << tPathLength << " geomlimit= " << geomlimit |
---|
[819] | 629 | // << " currentMinimalStep= " << currentMinimalStep << G4endl; |
---|
| 630 | return tPathLength ; |
---|
| 631 | } |
---|
| 632 | |
---|
| 633 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 634 | |
---|
| 635 | G4double G4UrbanMscModel::ComputeGeomPathLength(G4double) |
---|
| 636 | { |
---|
| 637 | lambdaeff = lambda0; |
---|
| 638 | par1 = -1. ; |
---|
| 639 | par2 = par3 = 0. ; |
---|
| 640 | |
---|
| 641 | // do the true -> geom transformation |
---|
| 642 | zPathLength = tPathLength; |
---|
| 643 | |
---|
| 644 | // z = t for very small tPathLength |
---|
| 645 | if(tPathLength < tlimitminfix) return zPathLength; |
---|
| 646 | |
---|
| 647 | // this correction needed to run MSC with eIoni and eBrem inactivated |
---|
| 648 | // and makes no harm for a normal run |
---|
| 649 | if(tPathLength > currentRange) |
---|
| 650 | tPathLength = currentRange ; |
---|
| 651 | |
---|
| 652 | G4double tau = tPathLength/lambda0 ; |
---|
| 653 | |
---|
| 654 | if ((tau <= tausmall) || insideskin) { |
---|
| 655 | zPathLength = tPathLength; |
---|
| 656 | if(zPathLength > lambda0) zPathLength = lambda0; |
---|
| 657 | return zPathLength; |
---|
| 658 | } |
---|
| 659 | |
---|
| 660 | G4double zmean = tPathLength; |
---|
| 661 | if (tPathLength < currentRange*dtrl) { |
---|
| 662 | if(tau < taulim) zmean = tPathLength*(1.-0.5*tau) ; |
---|
| 663 | else zmean = lambda0*(1.-exp(-tau)); |
---|
| 664 | } else if(currentKinEnergy < mass) { |
---|
| 665 | par1 = 1./currentRange ; |
---|
| 666 | par2 = 1./(par1*lambda0) ; |
---|
| 667 | par3 = 1.+par2 ; |
---|
| 668 | if(tPathLength < currentRange) |
---|
| 669 | zmean = (1.-exp(par3*log(1.-tPathLength/currentRange)))/(par1*par3) ; |
---|
| 670 | else |
---|
| 671 | zmean = 1./(par1*par3) ; |
---|
| 672 | } else { |
---|
| 673 | G4double T1 = theManager->GetEnergy(particle,currentRange-tPathLength,couple); |
---|
| 674 | G4double lambda1 = GetLambda(T1); |
---|
| 675 | |
---|
| 676 | par1 = (lambda0-lambda1)/(lambda0*tPathLength) ; |
---|
| 677 | par2 = 1./(par1*lambda0) ; |
---|
| 678 | par3 = 1.+par2 ; |
---|
| 679 | zmean = (1.-exp(par3*log(lambda1/lambda0)))/(par1*par3) ; |
---|
| 680 | } |
---|
| 681 | |
---|
| 682 | zPathLength = zmean ; |
---|
| 683 | |
---|
| 684 | // sample z |
---|
| 685 | if(samplez) |
---|
| 686 | { |
---|
[1055] | 687 | const G4double ztmax = 0.99 ; |
---|
[819] | 688 | G4double zt = zmean/tPathLength ; |
---|
| 689 | |
---|
| 690 | if (tPathLength > stepmin && zt < ztmax) |
---|
| 691 | { |
---|
| 692 | G4double u,cz1; |
---|
[1055] | 693 | if(zt >= third) |
---|
[819] | 694 | { |
---|
| 695 | G4double cz = 0.5*(3.*zt-1.)/(1.-zt) ; |
---|
| 696 | cz1 = 1.+cz ; |
---|
| 697 | G4double u0 = cz/cz1 ; |
---|
| 698 | G4double grej ; |
---|
| 699 | do { |
---|
| 700 | u = exp(log(G4UniformRand())/cz1) ; |
---|
| 701 | grej = exp(cz*log(u/u0))*(1.-u)/(1.-u0) ; |
---|
| 702 | } while (grej < G4UniformRand()) ; |
---|
| 703 | } |
---|
| 704 | else |
---|
| 705 | { |
---|
| 706 | cz1 = 1./zt-1.; |
---|
| 707 | u = 1.-exp(log(G4UniformRand())/cz1) ; |
---|
| 708 | } |
---|
| 709 | zPathLength = tPathLength*u ; |
---|
| 710 | } |
---|
| 711 | } |
---|
| 712 | |
---|
| 713 | if(zPathLength > lambda0) zPathLength = lambda0; |
---|
| 714 | |
---|
| 715 | return zPathLength; |
---|
| 716 | } |
---|
| 717 | |
---|
| 718 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 719 | |
---|
| 720 | G4double G4UrbanMscModel::ComputeTrueStepLength(G4double geomStepLength) |
---|
| 721 | { |
---|
| 722 | // step defined other than transportation |
---|
| 723 | if(geomStepLength == zPathLength && tPathLength <= currentRange) |
---|
| 724 | return tPathLength; |
---|
| 725 | |
---|
| 726 | // t = z for very small step |
---|
| 727 | zPathLength = geomStepLength; |
---|
| 728 | tPathLength = geomStepLength; |
---|
| 729 | if(geomStepLength < tlimitminfix) return tPathLength; |
---|
| 730 | |
---|
| 731 | // recalculation |
---|
| 732 | if((geomStepLength > lambda0*tausmall) && !insideskin) |
---|
| 733 | { |
---|
| 734 | if(par1 < 0.) |
---|
| 735 | tPathLength = -lambda0*log(1.-geomStepLength/lambda0) ; |
---|
| 736 | else |
---|
| 737 | { |
---|
| 738 | if(par1*par3*geomStepLength < 1.) |
---|
| 739 | tPathLength = (1.-exp(log(1.-par1*par3*geomStepLength)/par3))/par1 ; |
---|
| 740 | else |
---|
| 741 | tPathLength = currentRange; |
---|
| 742 | } |
---|
| 743 | } |
---|
| 744 | if(tPathLength < geomStepLength) tPathLength = geomStepLength; |
---|
| 745 | |
---|
| 746 | return tPathLength; |
---|
| 747 | } |
---|
| 748 | |
---|
| 749 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 750 | |
---|
| 751 | G4double G4UrbanMscModel::ComputeTheta0(G4double trueStepLength, |
---|
| 752 | G4double KineticEnergy) |
---|
| 753 | { |
---|
| 754 | // for all particles take the width of the central part |
---|
| 755 | // from a parametrization similar to the Highland formula |
---|
| 756 | // ( Highland formula: Particle Physics Booklet, July 2002, eq. 26.10) |
---|
| 757 | const G4double c_highland = 13.6*MeV ; |
---|
| 758 | G4double betacp = sqrt(currentKinEnergy*(currentKinEnergy+2.*mass)* |
---|
| 759 | KineticEnergy*(KineticEnergy+2.*mass)/ |
---|
| 760 | ((currentKinEnergy+mass)*(KineticEnergy+mass))); |
---|
[1055] | 761 | y = trueStepLength/currentRadLength; |
---|
[819] | 762 | G4double theta0 = c_highland*std::abs(charge)*sqrt(y)/betacp; |
---|
| 763 | y = log(y); |
---|
[1055] | 764 | // correction factor from e-/proton scattering data |
---|
| 765 | G4double corr = coeffth1+coeffth2*y; |
---|
| 766 | if(y < -6.5) corr -= 0.011*(6.5+y); |
---|
| 767 | theta0 *= corr ; |
---|
| 768 | |
---|
[819] | 769 | return theta0; |
---|
| 770 | } |
---|
| 771 | |
---|
| 772 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 773 | |
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| 774 | void G4UrbanMscModel::SampleScattering(const G4DynamicParticle* dynParticle, |
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| 775 | G4double safety) |
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| 776 | { |
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| 777 | G4double kineticEnergy = dynParticle->GetKineticEnergy(); |
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[1055] | 778 | |
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[961] | 779 | if((kineticEnergy <= 0.0) || (tPathLength <= tlimitminfix) || |
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[1055] | 780 | (tPathLength/tausmall < lambda0)) return; |
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[819] | 781 | |
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| 782 | G4double cth = SampleCosineTheta(tPathLength,kineticEnergy); |
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[1055] | 783 | |
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[819] | 784 | // protection against 'bad' cth values |
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[1055] | 785 | if(std::abs(cth) > 1.) return; |
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[961] | 786 | |
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[819] | 787 | G4double sth = sqrt((1.0 - cth)*(1.0 + cth)); |
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| 788 | G4double phi = twopi*G4UniformRand(); |
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| 789 | G4double dirx = sth*cos(phi); |
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| 790 | G4double diry = sth*sin(phi); |
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| 791 | |
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| 792 | G4ThreeVector oldDirection = dynParticle->GetMomentumDirection(); |
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| 793 | G4ThreeVector newDirection(dirx,diry,cth); |
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| 794 | newDirection.rotateUz(oldDirection); |
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| 795 | fParticleChange->ProposeMomentumDirection(newDirection); |
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| 796 | |
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| 797 | if (latDisplasment && safety > tlimitminfix) { |
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| 798 | |
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| 799 | G4double r = SampleDisplacement(); |
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[1055] | 800 | /* |
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[819] | 801 | G4cout << "G4UrbanMscModel::SampleSecondaries: e(MeV)= " << kineticEnergy |
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| 802 | << " sinTheta= " << sth << " r(mm)= " << r |
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| 803 | << " trueStep(mm)= " << tPathLength |
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| 804 | << " geomStep(mm)= " << zPathLength |
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| 805 | << G4endl; |
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[1055] | 806 | */ |
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[819] | 807 | if(r > 0.) |
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| 808 | { |
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| 809 | G4double latcorr = LatCorrelation(); |
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| 810 | if(latcorr > r) latcorr = r; |
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| 811 | |
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| 812 | // sample direction of lateral displacement |
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| 813 | // compute it from the lateral correlation |
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| 814 | G4double Phi = 0.; |
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[1055] | 815 | if(std::abs(r*sth) < latcorr) |
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[819] | 816 | Phi = twopi*G4UniformRand(); |
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[1055] | 817 | else |
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| 818 | { |
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[819] | 819 | G4double psi = std::acos(latcorr/(r*sth)); |
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[1055] | 820 | if(G4UniformRand() < 0.5) |
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| 821 | Phi = phi+psi; |
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| 822 | else |
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| 823 | Phi = phi-psi; |
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| 824 | } |
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[819] | 825 | |
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| 826 | dirx = std::cos(Phi); |
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| 827 | diry = std::sin(Phi); |
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| 828 | |
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| 829 | G4ThreeVector latDirection(dirx,diry,0.0); |
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| 830 | latDirection.rotateUz(oldDirection); |
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| 831 | |
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[1055] | 832 | ComputeDisplacement(fParticleChange, latDirection, r, safety); |
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| 833 | } |
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[819] | 834 | } |
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| 835 | } |
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| 836 | |
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| 837 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 838 | |
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| 839 | G4double G4UrbanMscModel::SampleCosineTheta(G4double trueStepLength, |
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| 840 | G4double KineticEnergy) |
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| 841 | { |
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| 842 | G4double cth = 1. ; |
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| 843 | G4double tau = trueStepLength/lambda0 ; |
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| 844 | |
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| 845 | Zeff = couple->GetMaterial()->GetTotNbOfElectPerVolume()/ |
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| 846 | couple->GetMaterial()->GetTotNbOfAtomsPerVolume() ; |
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| 847 | |
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[1055] | 848 | if(Zold != Zeff) |
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| 849 | UpdateCache(); |
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| 850 | |
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[819] | 851 | if(insideskin) |
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| 852 | { |
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| 853 | //no scattering, single or plural scattering |
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| 854 | G4double mean = trueStepLength/stepmin ; |
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| 855 | |
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| 856 | G4int n = G4Poisson(mean); |
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| 857 | if(n > 0) |
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| 858 | { |
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[1055] | 859 | //screening (Moliere-Bethe) |
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| 860 | G4double mom2 = KineticEnergy*(2.*mass+KineticEnergy); |
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| 861 | G4double beta2 = mom2/((KineticEnergy+mass)*(KineticEnergy+mass)); |
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| 862 | G4double ascr = scr1/mom2; |
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| 863 | ascr *= 1.13+scr2/beta2; |
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| 864 | G4double ascr1 = 1.+2.*ascr; |
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[819] | 865 | G4double bp1=ascr1+1.; |
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| 866 | G4double bm1=ascr1-1.; |
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[1055] | 867 | |
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[819] | 868 | // single scattering from screened Rutherford x-section |
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| 869 | G4double ct,st,phi; |
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| 870 | G4double sx=0.,sy=0.,sz=0.; |
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| 871 | for(G4int i=1; i<=n; i++) |
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| 872 | { |
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| 873 | ct = ascr1-bp1*bm1/(2.*G4UniformRand()+bm1); |
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| 874 | if(ct < -1.) ct = -1.; |
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| 875 | if(ct > 1.) ct = 1.; |
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| 876 | st = sqrt(1.-ct*ct); |
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| 877 | phi = twopi*G4UniformRand(); |
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| 878 | sx += st*cos(phi); |
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| 879 | sy += st*sin(phi); |
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| 880 | sz += ct; |
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| 881 | } |
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| 882 | cth = sz/sqrt(sx*sx+sy*sy+sz*sz); |
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| 883 | } |
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| 884 | } |
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| 885 | else |
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| 886 | { |
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| 887 | if(trueStepLength >= currentRange*dtrl) |
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| 888 | { |
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| 889 | if(par1*trueStepLength < 1.) |
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| 890 | tau = -par2*log(1.-par1*trueStepLength) ; |
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| 891 | // for the case if ioni/brems are inactivated |
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| 892 | // see the corresponding condition in ComputeGeomPathLength |
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| 893 | else if(1.-KineticEnergy/currentKinEnergy > taulim) |
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| 894 | tau = taubig ; |
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| 895 | } |
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| 896 | currentTau = tau ; |
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| 897 | lambdaeff = trueStepLength/currentTau; |
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| 898 | currentRadLength = couple->GetMaterial()->GetRadlen(); |
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| 899 | |
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| 900 | if (tau >= taubig) cth = -1.+2.*G4UniformRand(); |
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| 901 | else if (tau >= tausmall) |
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| 902 | { |
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[1055] | 903 | G4double xsi = 3.0; |
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| 904 | G4double x0 = 1.; |
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[819] | 905 | G4double a = 1., ea = 0., eaa = 1.; |
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[1055] | 906 | G4double b=2.,b1=3.,bx=1.,eb1=3.,ebx=1.; |
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| 907 | G4double prob = 1. , qprob = 1. ; |
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[819] | 908 | G4double xmean1 = 1., xmean2 = 0.; |
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[1055] | 909 | G4double xmeanth = exp(-tau); |
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| 910 | G4double x2meanth = (1.+2.*exp(-2.5*tau))/3.; |
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| 911 | |
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| 912 | G4double relloss = 1.-KineticEnergy/currentKinEnergy; |
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| 913 | if(relloss > rellossmax) |
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| 914 | return SimpleScattering(xmeanth,x2meanth); |
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| 915 | |
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[819] | 916 | G4double theta0 = ComputeTheta0(trueStepLength,KineticEnergy); |
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| 917 | |
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[1055] | 918 | // protection for very small angles |
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[819] | 919 | if(theta0 < tausmall) return cth; |
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[1055] | 920 | |
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| 921 | if(theta0 > theta0max) |
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| 922 | return SimpleScattering(xmeanth,x2meanth); |
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[819] | 923 | G4double sth = sin(0.5*theta0); |
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| 924 | a = 0.25/(sth*sth); |
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| 925 | |
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[1055] | 926 | ea = exp(-xsi); |
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| 927 | eaa = 1.-ea ; |
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| 928 | xmean1 = 1.-(1.-(1.+xsi)*ea)/(a*eaa); |
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| 929 | x0 = 1.-xsi/a; |
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[819] | 930 | |
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[1055] | 931 | if(xmean1 <= 0.999*xmeanth) |
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| 932 | return SimpleScattering(xmeanth,x2meanth); |
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[819] | 933 | |
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[1055] | 934 | // from MUSCAT H,Be,Fe data |
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| 935 | G4double c = coeffc1; |
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| 936 | if(y > -13.5) |
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| 937 | c += coeffc2*exp(3.*log(y+13.5)); |
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| 938 | |
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| 939 | if(abs(c-3.) < 0.001) c = 3.001; |
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| 940 | if(abs(c-2.) < 0.001) c = 2.001; |
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| 941 | |
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| 942 | G4double c1 = c-1.; |
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| 943 | |
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| 944 | //from continuity of derivatives |
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| 945 | b = 1.+(c-xsi)/a; |
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| 946 | |
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| 947 | b1 = b+1.; |
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| 948 | bx = c/a; |
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| 949 | eb1 = exp(c1*log(b1)); |
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| 950 | ebx = exp(c1*log(bx)); |
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| 951 | |
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| 952 | xmean2 = (x0*eb1+ebx-(eb1*bx-b1*ebx)/(c-2.))/(eb1-ebx); |
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| 953 | |
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| 954 | G4double f1x0 = a*ea/eaa; |
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| 955 | G4double f2x0 = c1*eb1/(bx*(eb1-ebx)); |
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| 956 | prob = f2x0/(f1x0+f2x0); |
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| 957 | |
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| 958 | qprob = xmeanth/(prob*xmean1+(1.-prob)*xmean2); |
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| 959 | |
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| 960 | // sampling of costheta |
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| 961 | if(G4UniformRand() < qprob) |
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[819] | 962 | { |
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[1055] | 963 | if(G4UniformRand() < prob) |
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| 964 | cth = 1.+log(ea+G4UniformRand()*eaa)/a ; |
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[819] | 965 | else |
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[1055] | 966 | cth = b-b1*bx/exp(log(ebx+(eb1-ebx)*G4UniformRand())/c1) ; |
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[819] | 967 | } |
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| 968 | else |
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[1055] | 969 | cth = -1.+2.*G4UniformRand(); |
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[819] | 970 | } |
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| 971 | } |
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| 972 | return cth ; |
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| 973 | } |
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| 974 | |
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| 975 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 976 | |
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[1055] | 977 | G4double G4UrbanMscModel::SimpleScattering(G4double xmeanth,G4double x2meanth) |
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| 978 | { |
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| 979 | // 'large angle scattering' |
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| 980 | // 2 model functions with correct xmean and x2mean |
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| 981 | G4double a = (2.*xmeanth+9.*x2meanth-3.)/(2.*xmeanth-3.*x2meanth+1.); |
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| 982 | G4double prob = (a+2.)*xmeanth/a; |
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| 983 | |
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| 984 | // sampling |
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| 985 | G4double cth = 1.; |
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| 986 | if(G4UniformRand() < prob) |
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| 987 | cth = -1.+2.*exp(log(G4UniformRand())/(a+1.)); |
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| 988 | else |
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| 989 | cth = -1.+2.*G4UniformRand(); |
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| 990 | return cth; |
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| 991 | } |
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| 992 | |
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| 993 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 994 | |
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[819] | 995 | G4double G4UrbanMscModel::SampleDisplacement() |
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| 996 | { |
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| 997 | const G4double kappa = 2.5; |
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| 998 | const G4double kappapl1 = kappa+1.; |
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| 999 | const G4double kappami1 = kappa-1.; |
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| 1000 | G4double rmean = 0.0; |
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| 1001 | if ((currentTau >= tausmall) && !insideskin) { |
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| 1002 | if (currentTau < taulim) { |
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| 1003 | rmean = kappa*currentTau*currentTau*currentTau* |
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| 1004 | (1.-kappapl1*currentTau*0.25)/6. ; |
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| 1005 | |
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| 1006 | } else { |
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| 1007 | G4double etau = 0.0; |
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| 1008 | if (currentTau<taubig) etau = exp(-currentTau); |
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| 1009 | rmean = -kappa*currentTau; |
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| 1010 | rmean = -exp(rmean)/(kappa*kappami1); |
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| 1011 | rmean += currentTau-kappapl1/kappa+kappa*etau/kappami1; |
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| 1012 | } |
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| 1013 | if (rmean>0.) rmean = 2.*lambdaeff*sqrt(rmean/3.0); |
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| 1014 | else rmean = 0.; |
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| 1015 | } |
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| 1016 | |
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| 1017 | // protection against z > t ........................... |
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| 1018 | if(rmean > 0.) { |
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| 1019 | G4double zt = (tPathLength-zPathLength)*(tPathLength+zPathLength); |
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| 1020 | if(zt <= 0.) |
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| 1021 | rmean = 0.; |
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| 1022 | else if(rmean*rmean > zt) |
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| 1023 | rmean = sqrt(zt); |
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| 1024 | } |
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| 1025 | return rmean; |
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| 1026 | } |
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| 1027 | |
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| 1028 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 1029 | |
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| 1030 | G4double G4UrbanMscModel::LatCorrelation() |
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| 1031 | { |
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| 1032 | const G4double kappa = 2.5; |
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| 1033 | const G4double kappami1 = kappa-1.; |
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| 1034 | |
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| 1035 | G4double latcorr = 0.; |
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| 1036 | if((currentTau >= tausmall) && !insideskin) |
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| 1037 | { |
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| 1038 | if(currentTau < taulim) |
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| 1039 | latcorr = lambdaeff*kappa*currentTau*currentTau* |
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| 1040 | (1.-(kappa+1.)*currentTau/3.)/3.; |
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| 1041 | else |
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| 1042 | { |
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| 1043 | G4double etau = 0.; |
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| 1044 | if(currentTau < taubig) etau = exp(-currentTau); |
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| 1045 | latcorr = -kappa*currentTau; |
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| 1046 | latcorr = exp(latcorr)/kappami1; |
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| 1047 | latcorr += 1.-kappa*etau/kappami1 ; |
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| 1048 | latcorr *= 2.*lambdaeff/3. ; |
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| 1049 | } |
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| 1050 | } |
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| 1051 | |
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| 1052 | return latcorr; |
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| 1053 | } |
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| 1054 | |
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| 1055 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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