[1197] | 1 | // |
---|
| 2 | // ******************************************************************** |
---|
| 3 | // * License and Disclaimer * |
---|
| 4 | // * * |
---|
| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
---|
| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
---|
| 7 | // * conditions of the Geant4 Software License, included in the file * |
---|
| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
---|
| 9 | // * include a list of copyright holders. * |
---|
| 10 | // * * |
---|
| 11 | // * Neither the authors of this software system, nor their employing * |
---|
| 12 | // * institutes,nor the agencies providing financial support for this * |
---|
| 13 | // * work make any representation or warranty, express or implied, * |
---|
| 14 | // * regarding this software system or assume any liability for its * |
---|
| 15 | // * use. Please see the license in the file LICENSE and URL above * |
---|
| 16 | // * for the full disclaimer and the limitation of liability. * |
---|
| 17 | // * * |
---|
| 18 | // * This code implementation is the result of the scientific and * |
---|
| 19 | // * technical work of the GEANT4 collaboration. * |
---|
| 20 | // * By using, copying, modifying or distributing the software (or * |
---|
| 21 | // * any work based on the software) you agree to acknowledge its * |
---|
| 22 | // * use in resulting scientific publications, and indicate your * |
---|
| 23 | // * acceptance of all terms of the Geant4 Software license. * |
---|
| 24 | // ******************************************************************** |
---|
| 25 | // |
---|
| 26 | // |
---|
| 27 | // $Id: G4UrbanMscModel92.cc,v 1.1 2009/11/01 13:05:01 vnivanch Exp $ |
---|
[1228] | 28 | // GEANT4 tag $Name: geant4-09-03 $ |
---|
[1197] | 29 | // |
---|
| 30 | // ------------------------------------------------------------------- |
---|
| 31 | // |
---|
| 32 | // GEANT4 Class file |
---|
| 33 | // |
---|
| 34 | // |
---|
| 35 | // File name: G4UrbanMscModel92 |
---|
| 36 | // |
---|
| 37 | // Author: Laszlo Urban |
---|
| 38 | // |
---|
| 39 | // Creation date: 06.03.2008 |
---|
| 40 | // |
---|
| 41 | // Modifications: |
---|
| 42 | // |
---|
| 43 | // 06-03-2008 starting point : G4UrbanMscModel2 = G4UrbanMscModel 9.1 ref 02 |
---|
| 44 | // |
---|
| 45 | // 13-03-08 Bug in SampleScattering (which caused lateral asymmetry) fixed |
---|
| 46 | // (L.Urban) |
---|
| 47 | // |
---|
| 48 | // 14-03-08 Simplification of step limitation in ComputeTruePathLengthLimit, |
---|
| 49 | // + tlimitmin is the same for UseDistancetoBoundary and |
---|
| 50 | // UseSafety (L.Urban) |
---|
| 51 | // |
---|
| 52 | // 16-03-08 Reorganization of SampleCosineTheta + new method SimpleScattering |
---|
| 53 | // SimpleScattering is used if the relative energy loss is too big |
---|
| 54 | // or theta0 is too big (see data members rellossmax, theta0max) |
---|
| 55 | // (L.Urban) |
---|
| 56 | // |
---|
| 57 | // 17-03-08 tuning of the correction factor in ComputeTheta0 (L.Urban) |
---|
| 58 | // |
---|
| 59 | // 19-03-08 exponent c of the 'tail' model function is not equal to 2 any more, |
---|
| 60 | // value of c has been extracted from some e- scattering data (L.Urban) |
---|
| 61 | // |
---|
| 62 | // 24-03-08 Step limitation in ComputeTruePathLengthLimit has been |
---|
| 63 | // simplified further + some data members have been removed (L.Urban) |
---|
| 64 | // |
---|
| 65 | // 24-07-08 central part of scattering angle (theta0) has been tuned |
---|
| 66 | // tail of the scattering angle distribution has been tuned |
---|
| 67 | // using some e- and proton scattering data |
---|
| 68 | // |
---|
| 69 | // 05-08-08 bugfix in ComputeTruePathLengthLimit (L.Urban) |
---|
| 70 | // |
---|
| 71 | // 09-10-08 theta0 and tail have been retuned using some e-,mu,proton |
---|
| 72 | // scattering data (L.Urban) |
---|
| 73 | // + single scattering without path length correction for |
---|
| 74 | // small steps (t < tlimitmin, for UseDistanceToBoundary only) |
---|
| 75 | // |
---|
| 76 | // 15-10-08 Moliere-Bethe screening in the single scattering part(L.Urban) |
---|
| 77 | // |
---|
| 78 | // 17-10-08 stepping similar to that in model (9.1) for UseSafety case |
---|
| 79 | // for e+/e- in order to speed up the code for calorimeters |
---|
| 80 | // |
---|
| 81 | // 23-10-08 bugfix in the screeningparameter of the single scattering part, |
---|
| 82 | // some technical change in order to speed up the code (UpdateCache) |
---|
| 83 | // |
---|
| 84 | // 27-10-08 bugfix in ComputeTruePathLengthLimit (affects UseDistanceToBoundary |
---|
| 85 | // stepping type only) (L.Urban) |
---|
| 86 | // |
---|
| 87 | // 28-10-09 V.Ivanchenko moved G4UrbanMscModel to G4UrbanMscModel92, |
---|
| 88 | // now it is a frozen version of the Urban model corresponding |
---|
| 89 | // to g4 9.2 |
---|
| 90 | |
---|
| 91 | // Class Description: |
---|
| 92 | // |
---|
| 93 | // Implementation of the model of multiple scattering based on |
---|
| 94 | // H.W.Lewis Phys Rev 78 (1950) 526 and others |
---|
| 95 | |
---|
| 96 | // ------------------------------------------------------------------- |
---|
| 97 | // In its present form the model can be used for simulation |
---|
| 98 | // of the e-/e+, muon and charged hadron multiple scattering |
---|
| 99 | // |
---|
| 100 | |
---|
| 101 | |
---|
| 102 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 103 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 104 | |
---|
| 105 | #include "G4UrbanMscModel92.hh" |
---|
| 106 | #include "Randomize.hh" |
---|
| 107 | #include "G4Electron.hh" |
---|
| 108 | #include "G4LossTableManager.hh" |
---|
| 109 | #include "G4ParticleChangeForMSC.hh" |
---|
| 110 | |
---|
| 111 | #include "G4Poisson.hh" |
---|
| 112 | #include "globals.hh" |
---|
| 113 | |
---|
| 114 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 115 | |
---|
| 116 | using namespace std; |
---|
| 117 | |
---|
| 118 | G4UrbanMscModel92::G4UrbanMscModel92(const G4String& nam) |
---|
| 119 | : G4VMscModel(nam), |
---|
| 120 | isInitialized(false) |
---|
| 121 | { |
---|
| 122 | masslimite = 0.6*MeV; |
---|
| 123 | lambdalimit = 1.*mm; |
---|
| 124 | fr = 0.02; |
---|
| 125 | // facsafety = 0.3; |
---|
| 126 | taubig = 8.0; |
---|
| 127 | tausmall = 1.e-16; |
---|
| 128 | taulim = 1.e-6; |
---|
| 129 | currentTau = taulim; |
---|
| 130 | tlimitminfix = 1.e-6*mm; |
---|
| 131 | stepmin = tlimitminfix; |
---|
| 132 | smallstep = 1.e10; |
---|
| 133 | currentRange = 0. ; |
---|
| 134 | rangeinit = 0.; |
---|
| 135 | tlimit = 1.e10*mm; |
---|
| 136 | tlimitmin = 10.*tlimitminfix; |
---|
| 137 | tgeom = 1.e50*mm; |
---|
| 138 | geombig = 1.e50*mm; |
---|
| 139 | geommin = 1.e-3*mm; |
---|
| 140 | geomlimit = geombig; |
---|
| 141 | presafety = 0.*mm; |
---|
| 142 | |
---|
| 143 | y = 0.; |
---|
| 144 | |
---|
| 145 | Zold = 0.; |
---|
| 146 | Zeff = 1.; |
---|
| 147 | Z2 = 1.; |
---|
| 148 | Z23 = 1.; |
---|
| 149 | lnZ = 0.; |
---|
| 150 | coeffth1 = 0.; |
---|
| 151 | coeffth2 = 0.; |
---|
| 152 | coeffc1 = 0.; |
---|
| 153 | coeffc2 = 0.; |
---|
| 154 | scr1ini = fine_structure_const*fine_structure_const* |
---|
| 155 | electron_mass_c2*electron_mass_c2/(0.885*0.885*4.*pi); |
---|
| 156 | scr2ini = 3.76*fine_structure_const*fine_structure_const; |
---|
| 157 | scr1 = 0.; |
---|
| 158 | scr2 = 0.; |
---|
| 159 | |
---|
| 160 | theta0max = pi/6.; |
---|
| 161 | rellossmax = 0.50; |
---|
| 162 | third = 1./3.; |
---|
| 163 | particle = 0; |
---|
| 164 | theManager = G4LossTableManager::Instance(); |
---|
| 165 | inside = false; |
---|
| 166 | insideskin = false; |
---|
| 167 | |
---|
| 168 | } |
---|
| 169 | |
---|
| 170 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 171 | |
---|
| 172 | G4UrbanMscModel92::~G4UrbanMscModel92() |
---|
| 173 | {} |
---|
| 174 | |
---|
| 175 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 176 | |
---|
| 177 | void G4UrbanMscModel92::Initialise(const G4ParticleDefinition* p, |
---|
| 178 | const G4DataVector&) |
---|
| 179 | { |
---|
| 180 | skindepth = skin*stepmin; |
---|
| 181 | if(isInitialized) return; |
---|
| 182 | // set values of some data members |
---|
| 183 | SetParticle(p); |
---|
| 184 | |
---|
| 185 | fParticleChange = GetParticleChangeForMSC(); |
---|
| 186 | InitialiseSafetyHelper(); |
---|
| 187 | |
---|
| 188 | isInitialized = true; |
---|
| 189 | } |
---|
| 190 | |
---|
| 191 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 192 | |
---|
| 193 | G4double G4UrbanMscModel92::ComputeCrossSectionPerAtom( |
---|
| 194 | const G4ParticleDefinition* part, |
---|
| 195 | G4double KineticEnergy, |
---|
| 196 | G4double AtomicNumber,G4double, |
---|
| 197 | G4double, G4double) |
---|
| 198 | { |
---|
| 199 | const G4double sigmafactor = twopi*classic_electr_radius*classic_electr_radius; |
---|
| 200 | const G4double epsfactor = 2.*electron_mass_c2*electron_mass_c2* |
---|
| 201 | Bohr_radius*Bohr_radius/(hbarc*hbarc); |
---|
| 202 | const G4double epsmin = 1.e-4 , epsmax = 1.e10; |
---|
| 203 | |
---|
| 204 | const G4double Zdat[15] = { 4., 6., 13., 20., 26., 29., 32., 38., 47., |
---|
| 205 | 50., 56., 64., 74., 79., 82. }; |
---|
| 206 | |
---|
| 207 | const G4double Tdat[22] = { 100*eV, 200*eV, 400*eV, 700*eV, |
---|
| 208 | 1*keV, 2*keV, 4*keV, 7*keV, |
---|
| 209 | 10*keV, 20*keV, 40*keV, 70*keV, |
---|
| 210 | 100*keV, 200*keV, 400*keV, 700*keV, |
---|
| 211 | 1*MeV, 2*MeV, 4*MeV, 7*MeV, |
---|
| 212 | 10*MeV, 20*MeV}; |
---|
| 213 | |
---|
| 214 | // corr. factors for e-/e+ lambda for T <= Tlim |
---|
| 215 | G4double celectron[15][22] = |
---|
| 216 | {{1.125,1.072,1.051,1.047,1.047,1.050,1.052,1.054, |
---|
| 217 | 1.054,1.057,1.062,1.069,1.075,1.090,1.105,1.111, |
---|
| 218 | 1.112,1.108,1.100,1.093,1.089,1.087 }, |
---|
| 219 | {1.408,1.246,1.143,1.096,1.077,1.059,1.053,1.051, |
---|
| 220 | 1.052,1.053,1.058,1.065,1.072,1.087,1.101,1.108, |
---|
| 221 | 1.109,1.105,1.097,1.090,1.086,1.082 }, |
---|
| 222 | {2.833,2.268,1.861,1.612,1.486,1.309,1.204,1.156, |
---|
| 223 | 1.136,1.114,1.106,1.106,1.109,1.119,1.129,1.132, |
---|
| 224 | 1.131,1.124,1.113,1.104,1.099,1.098 }, |
---|
| 225 | {3.879,3.016,2.380,2.007,1.818,1.535,1.340,1.236, |
---|
| 226 | 1.190,1.133,1.107,1.099,1.098,1.103,1.110,1.113, |
---|
| 227 | 1.112,1.105,1.096,1.089,1.085,1.098 }, |
---|
| 228 | {6.937,4.330,2.886,2.256,1.987,1.628,1.395,1.265, |
---|
| 229 | 1.203,1.122,1.080,1.065,1.061,1.063,1.070,1.073, |
---|
| 230 | 1.073,1.070,1.064,1.059,1.056,1.056 }, |
---|
| 231 | {9.616,5.708,3.424,2.551,2.204,1.762,1.485,1.330, |
---|
| 232 | 1.256,1.155,1.099,1.077,1.070,1.068,1.072,1.074, |
---|
| 233 | 1.074,1.070,1.063,1.059,1.056,1.052 }, |
---|
| 234 | {11.72,6.364,3.811,2.806,2.401,1.884,1.564,1.386, |
---|
| 235 | 1.300,1.180,1.112,1.082,1.073,1.066,1.068,1.069, |
---|
| 236 | 1.068,1.064,1.059,1.054,1.051,1.050 }, |
---|
| 237 | {18.08,8.601,4.569,3.183,2.662,2.025,1.646,1.439, |
---|
| 238 | 1.339,1.195,1.108,1.068,1.053,1.040,1.039,1.039, |
---|
| 239 | 1.039,1.037,1.034,1.031,1.030,1.036 }, |
---|
| 240 | {18.22,10.48,5.333,3.713,3.115,2.367,1.898,1.631, |
---|
| 241 | 1.498,1.301,1.171,1.105,1.077,1.048,1.036,1.033, |
---|
| 242 | 1.031,1.028,1.024,1.022,1.021,1.024 }, |
---|
| 243 | {14.14,10.65,5.710,3.929,3.266,2.453,1.951,1.669, |
---|
| 244 | 1.528,1.319,1.178,1.106,1.075,1.040,1.027,1.022, |
---|
| 245 | 1.020,1.017,1.015,1.013,1.013,1.020 }, |
---|
| 246 | {14.11,11.73,6.312,4.240,3.478,2.566,2.022,1.720, |
---|
| 247 | 1.569,1.342,1.186,1.102,1.065,1.022,1.003,0.997, |
---|
| 248 | 0.995,0.993,0.993,0.993,0.993,1.011 }, |
---|
| 249 | {22.76,20.01,8.835,5.287,4.144,2.901,2.219,1.855, |
---|
| 250 | 1.677,1.410,1.224,1.121,1.073,1.014,0.986,0.976, |
---|
| 251 | 0.974,0.972,0.973,0.974,0.975,0.987 }, |
---|
| 252 | {50.77,40.85,14.13,7.184,5.284,3.435,2.520,2.059, |
---|
| 253 | 1.837,1.512,1.283,1.153,1.091,1.010,0.969,0.954, |
---|
| 254 | 0.950,0.947,0.949,0.952,0.954,0.963 }, |
---|
| 255 | {65.87,59.06,15.87,7.570,5.567,3.650,2.682,2.182, |
---|
| 256 | 1.939,1.579,1.325,1.178,1.108,1.014,0.965,0.947, |
---|
| 257 | 0.941,0.938,0.940,0.944,0.946,0.954 }, |
---|
| 258 | {55.60,47.34,15.92,7.810,5.755,3.767,2.760,2.239, |
---|
| 259 | 1.985,1.609,1.343,1.188,1.113,1.013,0.960,0.939, |
---|
| 260 | 0.933,0.930,0.933,0.936,0.939,0.949 }}; |
---|
| 261 | |
---|
| 262 | G4double cpositron[15][22] = { |
---|
| 263 | {2.589,2.044,1.658,1.446,1.347,1.217,1.144,1.110, |
---|
| 264 | 1.097,1.083,1.080,1.086,1.092,1.108,1.123,1.131, |
---|
| 265 | 1.131,1.126,1.117,1.108,1.103,1.100 }, |
---|
| 266 | {3.904,2.794,2.079,1.710,1.543,1.325,1.202,1.145, |
---|
| 267 | 1.122,1.096,1.089,1.092,1.098,1.114,1.130,1.137, |
---|
| 268 | 1.138,1.132,1.122,1.113,1.108,1.102 }, |
---|
| 269 | {7.970,6.080,4.442,3.398,2.872,2.127,1.672,1.451, |
---|
| 270 | 1.357,1.246,1.194,1.179,1.178,1.188,1.201,1.205, |
---|
| 271 | 1.203,1.190,1.173,1.159,1.151,1.145 }, |
---|
| 272 | {9.714,7.607,5.747,4.493,3.815,2.777,2.079,1.715, |
---|
| 273 | 1.553,1.353,1.253,1.219,1.211,1.214,1.225,1.228, |
---|
| 274 | 1.225,1.210,1.191,1.175,1.166,1.174 }, |
---|
| 275 | {17.97,12.95,8.628,6.065,4.849,3.222,2.275,1.820, |
---|
| 276 | 1.624,1.382,1.259,1.214,1.202,1.202,1.214,1.219, |
---|
| 277 | 1.217,1.203,1.184,1.169,1.160,1.151 }, |
---|
| 278 | {24.83,17.06,10.84,7.355,5.767,3.707,2.546,1.996, |
---|
| 279 | 1.759,1.465,1.311,1.252,1.234,1.228,1.238,1.241, |
---|
| 280 | 1.237,1.222,1.201,1.184,1.174,1.159 }, |
---|
| 281 | {23.26,17.15,11.52,8.049,6.375,4.114,2.792,2.155, |
---|
| 282 | 1.880,1.535,1.353,1.281,1.258,1.247,1.254,1.256, |
---|
| 283 | 1.252,1.234,1.212,1.194,1.183,1.170 }, |
---|
| 284 | {22.33,18.01,12.86,9.212,7.336,4.702,3.117,2.348, |
---|
| 285 | 2.015,1.602,1.385,1.297,1.268,1.251,1.256,1.258, |
---|
| 286 | 1.254,1.237,1.214,1.195,1.185,1.179 }, |
---|
| 287 | {33.91,24.13,15.71,10.80,8.507,5.467,3.692,2.808, |
---|
| 288 | 2.407,1.873,1.564,1.425,1.374,1.330,1.324,1.320, |
---|
| 289 | 1.312,1.288,1.258,1.235,1.221,1.205 }, |
---|
| 290 | {32.14,24.11,16.30,11.40,9.015,5.782,3.868,2.917, |
---|
| 291 | 2.490,1.925,1.596,1.447,1.391,1.342,1.332,1.327, |
---|
| 292 | 1.320,1.294,1.264,1.240,1.226,1.214 }, |
---|
| 293 | {29.51,24.07,17.19,12.28,9.766,6.238,4.112,3.066, |
---|
| 294 | 2.602,1.995,1.641,1.477,1.414,1.356,1.342,1.336, |
---|
| 295 | 1.328,1.302,1.270,1.245,1.231,1.233 }, |
---|
| 296 | {38.19,30.85,21.76,15.35,12.07,7.521,4.812,3.498, |
---|
| 297 | 2.926,2.188,1.763,1.563,1.484,1.405,1.382,1.371, |
---|
| 298 | 1.361,1.330,1.294,1.267,1.251,1.239 }, |
---|
| 299 | {49.71,39.80,27.96,19.63,15.36,9.407,5.863,4.155, |
---|
| 300 | 3.417,2.478,1.944,1.692,1.589,1.480,1.441,1.423, |
---|
| 301 | 1.409,1.372,1.330,1.298,1.280,1.258 }, |
---|
| 302 | {59.25,45.08,30.36,20.83,16.15,9.834,6.166,4.407, |
---|
| 303 | 3.641,2.648,2.064,1.779,1.661,1.531,1.482,1.459, |
---|
| 304 | 1.442,1.400,1.354,1.319,1.299,1.272 }, |
---|
| 305 | {56.38,44.29,30.50,21.18,16.51,10.11,6.354,4.542, |
---|
| 306 | 3.752,2.724,2.116,1.817,1.692,1.554,1.499,1.474, |
---|
| 307 | 1.456,1.412,1.364,1.328,1.307,1.282 }}; |
---|
| 308 | |
---|
| 309 | //data/corrections for T > Tlim |
---|
| 310 | G4double Tlim = 10.*MeV; |
---|
| 311 | G4double beta2lim = Tlim*(Tlim+2.*electron_mass_c2)/ |
---|
| 312 | ((Tlim+electron_mass_c2)*(Tlim+electron_mass_c2)); |
---|
| 313 | G4double bg2lim = Tlim*(Tlim+2.*electron_mass_c2)/ |
---|
| 314 | (electron_mass_c2*electron_mass_c2); |
---|
| 315 | |
---|
| 316 | G4double sig0[15] = {0.2672*barn, 0.5922*barn, 2.653*barn, 6.235*barn, |
---|
| 317 | 11.69*barn , 13.24*barn , 16.12*barn, 23.00*barn , |
---|
| 318 | 35.13*barn , 39.95*barn , 50.85*barn, 67.19*barn , |
---|
| 319 | 91.15*barn , 104.4*barn , 113.1*barn}; |
---|
| 320 | |
---|
| 321 | G4double hecorr[15] = {120.70, 117.50, 105.00, 92.92, 79.23, 74.510, 68.29, |
---|
| 322 | 57.39, 41.97, 36.14, 24.53, 10.21, -7.855, -16.84, |
---|
| 323 | -22.30}; |
---|
| 324 | |
---|
| 325 | G4double sigma; |
---|
| 326 | SetParticle(part); |
---|
| 327 | |
---|
| 328 | G4double Z23 = 2.*log(AtomicNumber)/3.; Z23 = exp(Z23); |
---|
| 329 | |
---|
| 330 | // correction if particle .ne. e-/e+ |
---|
| 331 | // compute equivalent kinetic energy |
---|
| 332 | // lambda depends on p*beta .... |
---|
| 333 | |
---|
| 334 | G4double eKineticEnergy = KineticEnergy; |
---|
| 335 | |
---|
| 336 | if(mass > electron_mass_c2) |
---|
| 337 | { |
---|
| 338 | G4double TAU = KineticEnergy/mass ; |
---|
| 339 | G4double c = mass*TAU*(TAU+2.)/(electron_mass_c2*(TAU+1.)) ; |
---|
| 340 | G4double w = c-2. ; |
---|
| 341 | G4double tau = 0.5*(w+sqrt(w*w+4.*c)) ; |
---|
| 342 | eKineticEnergy = electron_mass_c2*tau ; |
---|
| 343 | } |
---|
| 344 | |
---|
| 345 | G4double eTotalEnergy = eKineticEnergy + electron_mass_c2 ; |
---|
| 346 | G4double beta2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2) |
---|
| 347 | /(eTotalEnergy*eTotalEnergy); |
---|
| 348 | G4double bg2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2) |
---|
| 349 | /(electron_mass_c2*electron_mass_c2); |
---|
| 350 | |
---|
| 351 | G4double eps = epsfactor*bg2/Z23; |
---|
| 352 | |
---|
| 353 | if (eps<epsmin) sigma = 2.*eps*eps; |
---|
| 354 | else if(eps<epsmax) sigma = log(1.+2.*eps)-2.*eps/(1.+2.*eps); |
---|
| 355 | else sigma = log(2.*eps)-1.+1./eps; |
---|
| 356 | |
---|
| 357 | sigma *= ChargeSquare*AtomicNumber*AtomicNumber/(beta2*bg2); |
---|
| 358 | |
---|
| 359 | // interpolate in AtomicNumber and beta2 |
---|
| 360 | G4double c1,c2,cc1,cc2,corr; |
---|
| 361 | |
---|
| 362 | // get bin number in Z |
---|
| 363 | G4int iZ = 14; |
---|
| 364 | while ((iZ>=0)&&(Zdat[iZ]>=AtomicNumber)) iZ -= 1; |
---|
| 365 | if (iZ==14) iZ = 13; |
---|
| 366 | if (iZ==-1) iZ = 0 ; |
---|
| 367 | |
---|
| 368 | G4double Z1 = Zdat[iZ]; |
---|
| 369 | G4double Z2 = Zdat[iZ+1]; |
---|
| 370 | G4double ratZ = (AtomicNumber-Z1)*(AtomicNumber+Z1)/ |
---|
| 371 | ((Z2-Z1)*(Z2+Z1)); |
---|
| 372 | |
---|
| 373 | if(eKineticEnergy <= Tlim) |
---|
| 374 | { |
---|
| 375 | // get bin number in T (beta2) |
---|
| 376 | G4int iT = 21; |
---|
| 377 | while ((iT>=0)&&(Tdat[iT]>=eKineticEnergy)) iT -= 1; |
---|
| 378 | if(iT==21) iT = 20; |
---|
| 379 | if(iT==-1) iT = 0 ; |
---|
| 380 | |
---|
| 381 | // calculate betasquare values |
---|
| 382 | G4double T = Tdat[iT], E = T + electron_mass_c2; |
---|
| 383 | G4double b2small = T*(E+electron_mass_c2)/(E*E); |
---|
| 384 | |
---|
| 385 | T = Tdat[iT+1]; E = T + electron_mass_c2; |
---|
| 386 | G4double b2big = T*(E+electron_mass_c2)/(E*E); |
---|
| 387 | G4double ratb2 = (beta2-b2small)/(b2big-b2small); |
---|
| 388 | |
---|
| 389 | if (charge < 0.) |
---|
| 390 | { |
---|
| 391 | c1 = celectron[iZ][iT]; |
---|
| 392 | c2 = celectron[iZ+1][iT]; |
---|
| 393 | cc1 = c1+ratZ*(c2-c1); |
---|
| 394 | |
---|
| 395 | c1 = celectron[iZ][iT+1]; |
---|
| 396 | c2 = celectron[iZ+1][iT+1]; |
---|
| 397 | cc2 = c1+ratZ*(c2-c1); |
---|
| 398 | |
---|
| 399 | corr = cc1+ratb2*(cc2-cc1); |
---|
| 400 | |
---|
| 401 | sigma *= sigmafactor/corr; |
---|
| 402 | } |
---|
| 403 | else |
---|
| 404 | { |
---|
| 405 | c1 = cpositron[iZ][iT]; |
---|
| 406 | c2 = cpositron[iZ+1][iT]; |
---|
| 407 | cc1 = c1+ratZ*(c2-c1); |
---|
| 408 | |
---|
| 409 | c1 = cpositron[iZ][iT+1]; |
---|
| 410 | c2 = cpositron[iZ+1][iT+1]; |
---|
| 411 | cc2 = c1+ratZ*(c2-c1); |
---|
| 412 | |
---|
| 413 | corr = cc1+ratb2*(cc2-cc1); |
---|
| 414 | |
---|
| 415 | sigma *= sigmafactor/corr; |
---|
| 416 | } |
---|
| 417 | } |
---|
| 418 | else |
---|
| 419 | { |
---|
| 420 | c1 = bg2lim*sig0[iZ]*(1.+hecorr[iZ]*(beta2-beta2lim))/bg2; |
---|
| 421 | c2 = bg2lim*sig0[iZ+1]*(1.+hecorr[iZ+1]*(beta2-beta2lim))/bg2; |
---|
| 422 | if((AtomicNumber >= Z1) && (AtomicNumber <= Z2)) |
---|
| 423 | sigma = c1+ratZ*(c2-c1) ; |
---|
| 424 | else if(AtomicNumber < Z1) |
---|
| 425 | sigma = AtomicNumber*AtomicNumber*c1/(Z1*Z1); |
---|
| 426 | else if(AtomicNumber > Z2) |
---|
| 427 | sigma = AtomicNumber*AtomicNumber*c2/(Z2*Z2); |
---|
| 428 | } |
---|
| 429 | return sigma; |
---|
| 430 | |
---|
| 431 | } |
---|
| 432 | |
---|
| 433 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 434 | |
---|
| 435 | G4double G4UrbanMscModel92::ComputeTruePathLengthLimit( |
---|
| 436 | const G4Track& track, |
---|
| 437 | G4PhysicsTable* theTable, |
---|
| 438 | G4double currentMinimalStep) |
---|
| 439 | { |
---|
| 440 | tPathLength = currentMinimalStep; |
---|
| 441 | G4StepPoint* sp = track.GetStep()->GetPreStepPoint(); |
---|
| 442 | G4StepStatus stepStatus = sp->GetStepStatus(); |
---|
| 443 | |
---|
| 444 | const G4DynamicParticle* dp = track.GetDynamicParticle(); |
---|
| 445 | |
---|
| 446 | if(stepStatus == fUndefined) { |
---|
| 447 | inside = false; |
---|
| 448 | insideskin = false; |
---|
| 449 | tlimit = geombig; |
---|
| 450 | SetParticle( dp->GetDefinition() ); |
---|
| 451 | } |
---|
| 452 | |
---|
| 453 | theLambdaTable = theTable; |
---|
| 454 | couple = track.GetMaterialCutsCouple(); |
---|
| 455 | currentMaterialIndex = couple->GetIndex(); |
---|
| 456 | currentKinEnergy = dp->GetKineticEnergy(); |
---|
| 457 | currentRange = |
---|
| 458 | theManager->GetRangeFromRestricteDEDX(particle,currentKinEnergy,couple); |
---|
| 459 | lambda0 = GetLambda(currentKinEnergy); |
---|
| 460 | |
---|
| 461 | // stop here if small range particle |
---|
| 462 | if(inside) return tPathLength; |
---|
| 463 | |
---|
| 464 | if(tPathLength > currentRange) tPathLength = currentRange; |
---|
| 465 | |
---|
| 466 | presafety = sp->GetSafety(); |
---|
| 467 | |
---|
| 468 | // G4cout << "G4UrbanMscModel92::ComputeTruePathLengthLimit tPathLength= " |
---|
| 469 | // <<tPathLength<<" safety= " << presafety |
---|
| 470 | // << " range= " <<currentRange<<G4endl; |
---|
| 471 | |
---|
| 472 | // far from geometry boundary |
---|
| 473 | if(currentRange < presafety) |
---|
| 474 | { |
---|
| 475 | inside = true; |
---|
| 476 | return tPathLength; |
---|
| 477 | } |
---|
| 478 | |
---|
| 479 | // standard version |
---|
| 480 | // |
---|
| 481 | if (steppingAlgorithm == fUseDistanceToBoundary) |
---|
| 482 | { |
---|
| 483 | //compute geomlimit and presafety |
---|
| 484 | G4double geomlimit = ComputeGeomLimit(track, presafety, currentRange); |
---|
| 485 | |
---|
| 486 | // is it far from boundary ? |
---|
| 487 | if(currentRange < presafety) |
---|
| 488 | { |
---|
| 489 | inside = true; |
---|
| 490 | return tPathLength; |
---|
| 491 | } |
---|
| 492 | |
---|
| 493 | smallstep += 1.; |
---|
| 494 | insideskin = false; |
---|
| 495 | |
---|
| 496 | if((stepStatus == fGeomBoundary) || (stepStatus == fUndefined)) |
---|
| 497 | { |
---|
| 498 | rangeinit = currentRange; |
---|
| 499 | if(stepStatus == fUndefined) smallstep = 1.e10; |
---|
| 500 | else smallstep = 1.; |
---|
| 501 | |
---|
| 502 | // constraint from the geometry |
---|
| 503 | if((geomlimit < geombig) && (geomlimit > geommin)) |
---|
| 504 | { |
---|
| 505 | if(stepStatus == fGeomBoundary) |
---|
| 506 | tgeom = geomlimit/facgeom; |
---|
| 507 | else |
---|
| 508 | tgeom = 2.*geomlimit/facgeom; |
---|
| 509 | } |
---|
| 510 | else |
---|
| 511 | tgeom = geombig; |
---|
| 512 | |
---|
| 513 | //define stepmin here (it depends on lambda!) |
---|
| 514 | //rough estimation of lambda_elastic/lambda_transport |
---|
| 515 | G4double rat = currentKinEnergy/MeV ; |
---|
| 516 | rat = 1.e-3/(rat*(10.+rat)) ; |
---|
| 517 | //stepmin ~ lambda_elastic |
---|
| 518 | stepmin = rat*lambda0; |
---|
| 519 | skindepth = skin*stepmin; |
---|
| 520 | |
---|
| 521 | //define tlimitmin |
---|
| 522 | tlimitmin = 10.*stepmin; |
---|
| 523 | if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix; |
---|
| 524 | |
---|
| 525 | } |
---|
| 526 | |
---|
| 527 | //step limit |
---|
| 528 | tlimit = facrange*rangeinit; |
---|
| 529 | if(tlimit < facsafety*presafety) |
---|
| 530 | tlimit = facsafety*presafety; |
---|
| 531 | |
---|
| 532 | //lower limit for tlimit |
---|
| 533 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
| 534 | |
---|
| 535 | if(tlimit > tgeom) tlimit = tgeom; |
---|
| 536 | |
---|
| 537 | // G4cout << "tgeom= " << tgeom << " geomlimit= " << geomlimit |
---|
| 538 | // << " tlimit= " << tlimit << " presafety= " << presafety << G4endl; |
---|
| 539 | |
---|
| 540 | // shortcut |
---|
| 541 | if((tPathLength < tlimit) && (tPathLength < presafety) && |
---|
| 542 | (smallstep >= skin) && (tPathLength < geomlimit-0.999*skindepth)) |
---|
| 543 | return tPathLength; |
---|
| 544 | |
---|
| 545 | // step reduction near to boundary |
---|
| 546 | if(smallstep < skin) |
---|
| 547 | { |
---|
| 548 | tlimit = stepmin; |
---|
| 549 | insideskin = true; |
---|
| 550 | } |
---|
| 551 | else if(geomlimit < geombig) |
---|
| 552 | { |
---|
| 553 | if(geomlimit > skindepth) |
---|
| 554 | { |
---|
| 555 | if(tlimit > geomlimit-0.999*skindepth) |
---|
| 556 | tlimit = geomlimit-0.999*skindepth; |
---|
| 557 | } |
---|
| 558 | else |
---|
| 559 | { |
---|
| 560 | insideskin = true; |
---|
| 561 | if(tlimit > stepmin) tlimit = stepmin; |
---|
| 562 | } |
---|
| 563 | } |
---|
| 564 | |
---|
| 565 | if(tlimit < stepmin) tlimit = stepmin; |
---|
| 566 | |
---|
| 567 | if(tPathLength > tlimit) tPathLength = tlimit ; |
---|
| 568 | |
---|
| 569 | } |
---|
| 570 | // for 'normal' simulation with or without magnetic field |
---|
| 571 | // there no small step/single scattering at boundaries |
---|
| 572 | else if(steppingAlgorithm == fUseSafety) |
---|
| 573 | { |
---|
| 574 | // compute presafety again if presafety <= 0 and no boundary |
---|
| 575 | // i.e. when it is needed for optimization purposes |
---|
| 576 | if((stepStatus != fGeomBoundary) && (presafety < tlimitminfix)) |
---|
| 577 | presafety = ComputeSafety(sp->GetPosition(),tPathLength); |
---|
| 578 | |
---|
| 579 | // is far from boundary |
---|
| 580 | if(currentRange < presafety) |
---|
| 581 | { |
---|
| 582 | inside = true; |
---|
| 583 | return tPathLength; |
---|
| 584 | } |
---|
| 585 | |
---|
| 586 | if((stepStatus == fGeomBoundary) || (stepStatus == fUndefined)) |
---|
| 587 | { |
---|
| 588 | rangeinit = currentRange; |
---|
| 589 | fr = facrange; |
---|
| 590 | // 9.1 like stepping for e+/e- only (not for muons,hadrons) |
---|
| 591 | if(mass < masslimite) |
---|
| 592 | { |
---|
| 593 | if(lambda0 > currentRange) |
---|
| 594 | rangeinit = lambda0; |
---|
| 595 | if(lambda0 > lambdalimit) |
---|
| 596 | fr *= 0.75+0.25*lambda0/lambdalimit; |
---|
| 597 | } |
---|
| 598 | |
---|
| 599 | //lower limit for tlimit |
---|
| 600 | G4double rat = currentKinEnergy/MeV ; |
---|
| 601 | rat = 1.e-3/(rat*(10.+rat)) ; |
---|
| 602 | tlimitmin = 10.*lambda0*rat; |
---|
| 603 | if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix; |
---|
| 604 | } |
---|
| 605 | //step limit |
---|
| 606 | tlimit = fr*rangeinit; |
---|
| 607 | |
---|
| 608 | if(tlimit < facsafety*presafety) |
---|
| 609 | tlimit = facsafety*presafety; |
---|
| 610 | |
---|
| 611 | //lower limit for tlimit |
---|
| 612 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
| 613 | |
---|
| 614 | if(tPathLength > tlimit) tPathLength = tlimit; |
---|
| 615 | } |
---|
| 616 | |
---|
| 617 | // version similar to 7.1 (needed for some experiments) |
---|
| 618 | else |
---|
| 619 | { |
---|
| 620 | if (stepStatus == fGeomBoundary) |
---|
| 621 | { |
---|
| 622 | if (currentRange > lambda0) tlimit = facrange*currentRange; |
---|
| 623 | else tlimit = facrange*lambda0; |
---|
| 624 | |
---|
| 625 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
| 626 | if(tPathLength > tlimit) tPathLength = tlimit; |
---|
| 627 | } |
---|
| 628 | } |
---|
| 629 | // G4cout << "tPathLength= " << tPathLength << " geomlimit= " << geomlimit |
---|
| 630 | // << " currentMinimalStep= " << currentMinimalStep << G4endl; |
---|
| 631 | return tPathLength ; |
---|
| 632 | } |
---|
| 633 | |
---|
| 634 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 635 | |
---|
| 636 | G4double G4UrbanMscModel92::ComputeGeomPathLength(G4double) |
---|
| 637 | { |
---|
| 638 | lambdaeff = lambda0; |
---|
| 639 | par1 = -1. ; |
---|
| 640 | par2 = par3 = 0. ; |
---|
| 641 | |
---|
| 642 | // do the true -> geom transformation |
---|
| 643 | zPathLength = tPathLength; |
---|
| 644 | |
---|
| 645 | // z = t for very small tPathLength |
---|
| 646 | if(tPathLength < tlimitminfix) return zPathLength; |
---|
| 647 | |
---|
| 648 | // this correction needed to run MSC with eIoni and eBrem inactivated |
---|
| 649 | // and makes no harm for a normal run |
---|
| 650 | if(tPathLength > currentRange) |
---|
| 651 | tPathLength = currentRange ; |
---|
| 652 | |
---|
| 653 | G4double tau = tPathLength/lambda0 ; |
---|
| 654 | |
---|
| 655 | if ((tau <= tausmall) || insideskin) { |
---|
| 656 | zPathLength = tPathLength; |
---|
| 657 | if(zPathLength > lambda0) zPathLength = lambda0; |
---|
| 658 | return zPathLength; |
---|
| 659 | } |
---|
| 660 | |
---|
| 661 | G4double zmean = tPathLength; |
---|
| 662 | if (tPathLength < currentRange*dtrl) { |
---|
| 663 | if(tau < taulim) zmean = tPathLength*(1.-0.5*tau) ; |
---|
| 664 | else zmean = lambda0*(1.-exp(-tau)); |
---|
| 665 | } else if(currentKinEnergy < mass) { |
---|
| 666 | par1 = 1./currentRange ; |
---|
| 667 | par2 = 1./(par1*lambda0) ; |
---|
| 668 | par3 = 1.+par2 ; |
---|
| 669 | if(tPathLength < currentRange) |
---|
| 670 | zmean = (1.-exp(par3*log(1.-tPathLength/currentRange)))/(par1*par3) ; |
---|
| 671 | else |
---|
| 672 | zmean = 1./(par1*par3) ; |
---|
| 673 | } else { |
---|
| 674 | G4double T1 = theManager->GetEnergy(particle,currentRange-tPathLength,couple); |
---|
| 675 | G4double lambda1 = GetLambda(T1); |
---|
| 676 | |
---|
| 677 | par1 = (lambda0-lambda1)/(lambda0*tPathLength) ; |
---|
| 678 | par2 = 1./(par1*lambda0) ; |
---|
| 679 | par3 = 1.+par2 ; |
---|
| 680 | zmean = (1.-exp(par3*log(lambda1/lambda0)))/(par1*par3) ; |
---|
| 681 | } |
---|
| 682 | |
---|
| 683 | zPathLength = zmean ; |
---|
| 684 | |
---|
| 685 | // sample z |
---|
| 686 | if(samplez) |
---|
| 687 | { |
---|
| 688 | const G4double ztmax = 0.99 ; |
---|
| 689 | G4double zt = zmean/tPathLength ; |
---|
| 690 | |
---|
| 691 | if (tPathLength > stepmin && zt < ztmax) |
---|
| 692 | { |
---|
| 693 | G4double u,cz1; |
---|
| 694 | if(zt >= third) |
---|
| 695 | { |
---|
| 696 | G4double cz = 0.5*(3.*zt-1.)/(1.-zt) ; |
---|
| 697 | cz1 = 1.+cz ; |
---|
| 698 | G4double u0 = cz/cz1 ; |
---|
| 699 | G4double grej ; |
---|
| 700 | do { |
---|
| 701 | u = exp(log(G4UniformRand())/cz1) ; |
---|
| 702 | grej = exp(cz*log(u/u0))*(1.-u)/(1.-u0) ; |
---|
| 703 | } while (grej < G4UniformRand()) ; |
---|
| 704 | } |
---|
| 705 | else |
---|
| 706 | { |
---|
| 707 | cz1 = 1./zt-1.; |
---|
| 708 | u = 1.-exp(log(G4UniformRand())/cz1) ; |
---|
| 709 | } |
---|
| 710 | zPathLength = tPathLength*u ; |
---|
| 711 | } |
---|
| 712 | } |
---|
| 713 | |
---|
| 714 | if(zPathLength > lambda0) zPathLength = lambda0; |
---|
| 715 | |
---|
| 716 | return zPathLength; |
---|
| 717 | } |
---|
| 718 | |
---|
| 719 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 720 | |
---|
| 721 | G4double G4UrbanMscModel92::ComputeTrueStepLength(G4double geomStepLength) |
---|
| 722 | { |
---|
| 723 | // step defined other than transportation |
---|
| 724 | if(geomStepLength == zPathLength && tPathLength <= currentRange) |
---|
| 725 | return tPathLength; |
---|
| 726 | |
---|
| 727 | // t = z for very small step |
---|
| 728 | zPathLength = geomStepLength; |
---|
| 729 | tPathLength = geomStepLength; |
---|
| 730 | if(geomStepLength < tlimitminfix) return tPathLength; |
---|
| 731 | |
---|
| 732 | // recalculation |
---|
| 733 | if((geomStepLength > lambda0*tausmall) && !insideskin) |
---|
| 734 | { |
---|
| 735 | if(par1 < 0.) |
---|
| 736 | tPathLength = -lambda0*log(1.-geomStepLength/lambda0) ; |
---|
| 737 | else |
---|
| 738 | { |
---|
| 739 | if(par1*par3*geomStepLength < 1.) |
---|
| 740 | tPathLength = (1.-exp(log(1.-par1*par3*geomStepLength)/par3))/par1 ; |
---|
| 741 | else |
---|
| 742 | tPathLength = currentRange; |
---|
| 743 | } |
---|
| 744 | } |
---|
| 745 | if(tPathLength < geomStepLength) tPathLength = geomStepLength; |
---|
| 746 | |
---|
| 747 | return tPathLength; |
---|
| 748 | } |
---|
| 749 | |
---|
| 750 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 751 | |
---|
| 752 | G4double G4UrbanMscModel92::ComputeTheta0(G4double trueStepLength, |
---|
| 753 | G4double KineticEnergy) |
---|
| 754 | { |
---|
| 755 | // for all particles take the width of the central part |
---|
| 756 | // from a parametrization similar to the Highland formula |
---|
| 757 | // ( Highland formula: Particle Physics Booklet, July 2002, eq. 26.10) |
---|
| 758 | const G4double c_highland = 13.6*MeV ; |
---|
| 759 | G4double betacp = sqrt(currentKinEnergy*(currentKinEnergy+2.*mass)* |
---|
| 760 | KineticEnergy*(KineticEnergy+2.*mass)/ |
---|
| 761 | ((currentKinEnergy+mass)*(KineticEnergy+mass))); |
---|
| 762 | y = trueStepLength/currentRadLength; |
---|
| 763 | G4double theta0 = c_highland*std::abs(charge)*sqrt(y)/betacp; |
---|
| 764 | y = log(y); |
---|
| 765 | // correction factor from e-/proton scattering data |
---|
| 766 | G4double corr = coeffth1+coeffth2*y; |
---|
| 767 | if(y < -6.5) corr -= 0.011*(6.5+y); |
---|
| 768 | theta0 *= corr ; |
---|
| 769 | |
---|
| 770 | return theta0; |
---|
| 771 | } |
---|
| 772 | |
---|
| 773 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 774 | |
---|
| 775 | void G4UrbanMscModel92::SampleScattering(const G4DynamicParticle* dynParticle, |
---|
| 776 | G4double safety) |
---|
| 777 | { |
---|
| 778 | G4double kineticEnergy = dynParticle->GetKineticEnergy(); |
---|
| 779 | |
---|
| 780 | if((kineticEnergy <= 0.0) || (tPathLength <= tlimitminfix) || |
---|
| 781 | (tPathLength/tausmall < lambda0)) return; |
---|
| 782 | |
---|
| 783 | G4double cth = SampleCosineTheta(tPathLength,kineticEnergy); |
---|
| 784 | |
---|
| 785 | // protection against 'bad' cth values |
---|
| 786 | if(std::abs(cth) > 1.) return; |
---|
| 787 | |
---|
| 788 | G4double sth = sqrt((1.0 - cth)*(1.0 + cth)); |
---|
| 789 | G4double phi = twopi*G4UniformRand(); |
---|
| 790 | G4double dirx = sth*cos(phi); |
---|
| 791 | G4double diry = sth*sin(phi); |
---|
| 792 | |
---|
| 793 | G4ThreeVector oldDirection = dynParticle->GetMomentumDirection(); |
---|
| 794 | G4ThreeVector newDirection(dirx,diry,cth); |
---|
| 795 | newDirection.rotateUz(oldDirection); |
---|
| 796 | fParticleChange->ProposeMomentumDirection(newDirection); |
---|
| 797 | |
---|
| 798 | if (latDisplasment && safety > tlimitminfix) { |
---|
| 799 | |
---|
| 800 | G4double r = SampleDisplacement(); |
---|
| 801 | /* |
---|
| 802 | G4cout << "G4UrbanMscModel92::SampleSecondaries: e(MeV)= " << kineticEnergy |
---|
| 803 | << " sinTheta= " << sth << " r(mm)= " << r |
---|
| 804 | << " trueStep(mm)= " << tPathLength |
---|
| 805 | << " geomStep(mm)= " << zPathLength |
---|
| 806 | << G4endl; |
---|
| 807 | */ |
---|
| 808 | if(r > 0.) |
---|
| 809 | { |
---|
| 810 | G4double latcorr = LatCorrelation(); |
---|
| 811 | if(latcorr > r) latcorr = r; |
---|
| 812 | |
---|
| 813 | // sample direction of lateral displacement |
---|
| 814 | // compute it from the lateral correlation |
---|
| 815 | G4double Phi = 0.; |
---|
| 816 | if(std::abs(r*sth) < latcorr) |
---|
| 817 | Phi = twopi*G4UniformRand(); |
---|
| 818 | else |
---|
| 819 | { |
---|
| 820 | G4double psi = std::acos(latcorr/(r*sth)); |
---|
| 821 | if(G4UniformRand() < 0.5) |
---|
| 822 | Phi = phi+psi; |
---|
| 823 | else |
---|
| 824 | Phi = phi-psi; |
---|
| 825 | } |
---|
| 826 | |
---|
| 827 | dirx = std::cos(Phi); |
---|
| 828 | diry = std::sin(Phi); |
---|
| 829 | |
---|
| 830 | G4ThreeVector latDirection(dirx,diry,0.0); |
---|
| 831 | latDirection.rotateUz(oldDirection); |
---|
| 832 | |
---|
| 833 | ComputeDisplacement(fParticleChange, latDirection, r, safety); |
---|
| 834 | } |
---|
| 835 | } |
---|
| 836 | } |
---|
| 837 | |
---|
| 838 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 839 | |
---|
| 840 | G4double G4UrbanMscModel92::SampleCosineTheta(G4double trueStepLength, |
---|
| 841 | G4double KineticEnergy) |
---|
| 842 | { |
---|
| 843 | G4double cth = 1. ; |
---|
| 844 | G4double tau = trueStepLength/lambda0 ; |
---|
| 845 | |
---|
| 846 | Zeff = couple->GetMaterial()->GetTotNbOfElectPerVolume()/ |
---|
| 847 | couple->GetMaterial()->GetTotNbOfAtomsPerVolume() ; |
---|
| 848 | |
---|
| 849 | if(Zold != Zeff) |
---|
| 850 | UpdateCache(); |
---|
| 851 | |
---|
| 852 | if(insideskin) |
---|
| 853 | { |
---|
| 854 | //no scattering, single or plural scattering |
---|
| 855 | G4double mean = trueStepLength/stepmin ; |
---|
| 856 | |
---|
| 857 | G4int n = G4Poisson(mean); |
---|
| 858 | if(n > 0) |
---|
| 859 | { |
---|
| 860 | //screening (Moliere-Bethe) |
---|
| 861 | G4double mom2 = KineticEnergy*(2.*mass+KineticEnergy); |
---|
| 862 | G4double beta2 = mom2/((KineticEnergy+mass)*(KineticEnergy+mass)); |
---|
| 863 | G4double ascr = scr1/mom2; |
---|
| 864 | ascr *= 1.13+scr2/beta2; |
---|
| 865 | G4double ascr1 = 1.+2.*ascr; |
---|
| 866 | G4double bp1=ascr1+1.; |
---|
| 867 | G4double bm1=ascr1-1.; |
---|
| 868 | |
---|
| 869 | // single scattering from screened Rutherford x-section |
---|
| 870 | G4double ct,st,phi; |
---|
| 871 | G4double sx=0.,sy=0.,sz=0.; |
---|
| 872 | for(G4int i=1; i<=n; i++) |
---|
| 873 | { |
---|
| 874 | ct = ascr1-bp1*bm1/(2.*G4UniformRand()+bm1); |
---|
| 875 | if(ct < -1.) ct = -1.; |
---|
| 876 | if(ct > 1.) ct = 1.; |
---|
| 877 | st = sqrt(1.-ct*ct); |
---|
| 878 | phi = twopi*G4UniformRand(); |
---|
| 879 | sx += st*cos(phi); |
---|
| 880 | sy += st*sin(phi); |
---|
| 881 | sz += ct; |
---|
| 882 | } |
---|
| 883 | cth = sz/sqrt(sx*sx+sy*sy+sz*sz); |
---|
| 884 | } |
---|
| 885 | } |
---|
| 886 | else |
---|
| 887 | { |
---|
| 888 | if(trueStepLength >= currentRange*dtrl) |
---|
| 889 | { |
---|
| 890 | if(par1*trueStepLength < 1.) |
---|
| 891 | tau = -par2*log(1.-par1*trueStepLength) ; |
---|
| 892 | // for the case if ioni/brems are inactivated |
---|
| 893 | // see the corresponding condition in ComputeGeomPathLength |
---|
| 894 | else if(1.-KineticEnergy/currentKinEnergy > taulim) |
---|
| 895 | tau = taubig ; |
---|
| 896 | } |
---|
| 897 | currentTau = tau ; |
---|
| 898 | lambdaeff = trueStepLength/currentTau; |
---|
| 899 | currentRadLength = couple->GetMaterial()->GetRadlen(); |
---|
| 900 | |
---|
| 901 | if (tau >= taubig) cth = -1.+2.*G4UniformRand(); |
---|
| 902 | else if (tau >= tausmall) |
---|
| 903 | { |
---|
| 904 | G4double xsi = 3.0; |
---|
| 905 | G4double x0 = 1.; |
---|
| 906 | G4double a = 1., ea = 0., eaa = 1.; |
---|
| 907 | G4double b=2.,b1=3.,bx=1.,eb1=3.,ebx=1.; |
---|
| 908 | G4double prob = 1. , qprob = 1. ; |
---|
| 909 | G4double xmean1 = 1., xmean2 = 0.; |
---|
| 910 | G4double xmeanth = exp(-tau); |
---|
| 911 | G4double x2meanth = (1.+2.*exp(-2.5*tau))/3.; |
---|
| 912 | |
---|
| 913 | G4double relloss = 1.-KineticEnergy/currentKinEnergy; |
---|
| 914 | if(relloss > rellossmax) |
---|
| 915 | return SimpleScattering(xmeanth,x2meanth); |
---|
| 916 | |
---|
| 917 | G4double theta0 = ComputeTheta0(trueStepLength,KineticEnergy); |
---|
| 918 | |
---|
| 919 | // protection for very small angles |
---|
| 920 | if(theta0 < tausmall) return cth; |
---|
| 921 | |
---|
| 922 | if(theta0 > theta0max) |
---|
| 923 | return SimpleScattering(xmeanth,x2meanth); |
---|
| 924 | G4double sth = sin(0.5*theta0); |
---|
| 925 | a = 0.25/(sth*sth); |
---|
| 926 | |
---|
| 927 | ea = exp(-xsi); |
---|
| 928 | eaa = 1.-ea ; |
---|
| 929 | xmean1 = 1.-(1.-(1.+xsi)*ea)/(a*eaa); |
---|
| 930 | x0 = 1.-xsi/a; |
---|
| 931 | |
---|
| 932 | if(xmean1 <= 0.999*xmeanth) |
---|
| 933 | return SimpleScattering(xmeanth,x2meanth); |
---|
| 934 | |
---|
| 935 | // from MUSCAT H,Be,Fe data |
---|
| 936 | G4double c = coeffc1; |
---|
| 937 | if(y > -13.5) |
---|
| 938 | c += coeffc2*exp(3.*log(y+13.5)); |
---|
| 939 | |
---|
| 940 | if(abs(c-3.) < 0.001) c = 3.001; |
---|
| 941 | if(abs(c-2.) < 0.001) c = 2.001; |
---|
| 942 | |
---|
| 943 | G4double c1 = c-1.; |
---|
| 944 | |
---|
| 945 | //from continuity of derivatives |
---|
| 946 | b = 1.+(c-xsi)/a; |
---|
| 947 | |
---|
| 948 | b1 = b+1.; |
---|
| 949 | bx = c/a; |
---|
| 950 | eb1 = exp(c1*log(b1)); |
---|
| 951 | ebx = exp(c1*log(bx)); |
---|
| 952 | |
---|
| 953 | xmean2 = (x0*eb1+ebx-(eb1*bx-b1*ebx)/(c-2.))/(eb1-ebx); |
---|
| 954 | |
---|
| 955 | G4double f1x0 = a*ea/eaa; |
---|
| 956 | G4double f2x0 = c1*eb1/(bx*(eb1-ebx)); |
---|
| 957 | prob = f2x0/(f1x0+f2x0); |
---|
| 958 | |
---|
| 959 | qprob = xmeanth/(prob*xmean1+(1.-prob)*xmean2); |
---|
| 960 | |
---|
| 961 | // sampling of costheta |
---|
| 962 | if(G4UniformRand() < qprob) |
---|
| 963 | { |
---|
| 964 | if(G4UniformRand() < prob) |
---|
| 965 | cth = 1.+log(ea+G4UniformRand()*eaa)/a ; |
---|
| 966 | else |
---|
| 967 | cth = b-b1*bx/exp(log(ebx+(eb1-ebx)*G4UniformRand())/c1) ; |
---|
| 968 | } |
---|
| 969 | else |
---|
| 970 | cth = -1.+2.*G4UniformRand(); |
---|
| 971 | } |
---|
| 972 | } |
---|
| 973 | return cth ; |
---|
| 974 | } |
---|
| 975 | |
---|
| 976 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 977 | |
---|
| 978 | G4double G4UrbanMscModel92::SimpleScattering(G4double xmeanth,G4double x2meanth) |
---|
| 979 | { |
---|
| 980 | // 'large angle scattering' |
---|
| 981 | // 2 model functions with correct xmean and x2mean |
---|
| 982 | G4double a = (2.*xmeanth+9.*x2meanth-3.)/(2.*xmeanth-3.*x2meanth+1.); |
---|
| 983 | G4double prob = (a+2.)*xmeanth/a; |
---|
| 984 | |
---|
| 985 | // sampling |
---|
| 986 | G4double cth = 1.; |
---|
| 987 | if(G4UniformRand() < prob) |
---|
| 988 | cth = -1.+2.*exp(log(G4UniformRand())/(a+1.)); |
---|
| 989 | else |
---|
| 990 | cth = -1.+2.*G4UniformRand(); |
---|
| 991 | return cth; |
---|
| 992 | } |
---|
| 993 | |
---|
| 994 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 995 | |
---|
| 996 | G4double G4UrbanMscModel92::SampleDisplacement() |
---|
| 997 | { |
---|
| 998 | const G4double kappa = 2.5; |
---|
| 999 | const G4double kappapl1 = kappa+1.; |
---|
| 1000 | const G4double kappami1 = kappa-1.; |
---|
| 1001 | G4double rmean = 0.0; |
---|
| 1002 | if ((currentTau >= tausmall) && !insideskin) { |
---|
| 1003 | if (currentTau < taulim) { |
---|
| 1004 | rmean = kappa*currentTau*currentTau*currentTau* |
---|
| 1005 | (1.-kappapl1*currentTau*0.25)/6. ; |
---|
| 1006 | |
---|
| 1007 | } else { |
---|
| 1008 | G4double etau = 0.0; |
---|
| 1009 | if (currentTau<taubig) etau = exp(-currentTau); |
---|
| 1010 | rmean = -kappa*currentTau; |
---|
| 1011 | rmean = -exp(rmean)/(kappa*kappami1); |
---|
| 1012 | rmean += currentTau-kappapl1/kappa+kappa*etau/kappami1; |
---|
| 1013 | } |
---|
| 1014 | if (rmean>0.) rmean = 2.*lambdaeff*sqrt(rmean/3.0); |
---|
| 1015 | else rmean = 0.; |
---|
| 1016 | } |
---|
| 1017 | |
---|
| 1018 | // protection against z > t ........................... |
---|
| 1019 | if(rmean > 0.) { |
---|
| 1020 | G4double zt = (tPathLength-zPathLength)*(tPathLength+zPathLength); |
---|
| 1021 | if(zt <= 0.) |
---|
| 1022 | rmean = 0.; |
---|
| 1023 | else if(rmean*rmean > zt) |
---|
| 1024 | rmean = sqrt(zt); |
---|
| 1025 | } |
---|
| 1026 | return rmean; |
---|
| 1027 | } |
---|
| 1028 | |
---|
| 1029 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 1030 | |
---|
| 1031 | G4double G4UrbanMscModel92::LatCorrelation() |
---|
| 1032 | { |
---|
| 1033 | const G4double kappa = 2.5; |
---|
| 1034 | const G4double kappami1 = kappa-1.; |
---|
| 1035 | |
---|
| 1036 | G4double latcorr = 0.; |
---|
| 1037 | if((currentTau >= tausmall) && !insideskin) |
---|
| 1038 | { |
---|
| 1039 | if(currentTau < taulim) |
---|
| 1040 | latcorr = lambdaeff*kappa*currentTau*currentTau* |
---|
| 1041 | (1.-(kappa+1.)*currentTau/3.)/3.; |
---|
| 1042 | else |
---|
| 1043 | { |
---|
| 1044 | G4double etau = 0.; |
---|
| 1045 | if(currentTau < taubig) etau = exp(-currentTau); |
---|
| 1046 | latcorr = -kappa*currentTau; |
---|
| 1047 | latcorr = exp(latcorr)/kappami1; |
---|
| 1048 | latcorr += 1.-kappa*etau/kappami1 ; |
---|
| 1049 | latcorr *= 2.*lambdaeff/3. ; |
---|
| 1050 | } |
---|
| 1051 | } |
---|
| 1052 | |
---|
| 1053 | return latcorr; |
---|
| 1054 | } |
---|
| 1055 | |
---|
| 1056 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|