Geant4 10.7.0
Toolkit for the simulation of the passage of particles through matter
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G4UrbanMscModel.cc
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25//
26//
27// -------------------------------------------------------------------
28//
29// GEANT4 Class file
30//
31//
32// File name: G4UrbanMscModel
33//
34// Author: Laszlo Urban
35//
36// Creation date: 19.02.2013
37//
38// Created from G4UrbanMscModel96
39//
40// New parametrization for theta0
41// Correction for very small step length
42//
43// Class Description:
44//
45// Implementation of the model of multiple scattering based on
46// H.W.Lewis Phys Rev 78 (1950) 526 and others
47
48// -------------------------------------------------------------------
49// In its present form the model can be used for simulation
50// of the e-/e+ multiple scattering
51//
52
53
54//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
55//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
56
57#include "G4UrbanMscModel.hh"
58#include "G4PhysicalConstants.hh"
59#include "G4SystemOfUnits.hh"
60#include "Randomize.hh"
61#include "G4Electron.hh"
62#include "G4Positron.hh"
63#include "G4LossTableManager.hh"
64#include "G4EmParameters.hh"
65#include "G4ParticleChangeForMSC.hh"
66#include "G4ProductionCutsTable.hh"
67
68#include "G4Poisson.hh"
69#include "G4Pow.hh"
70#include "globals.hh"
71#include "G4Log.hh"
72#include "G4Exp.hh"
73
74//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
75
76using namespace std;
77
78std::vector<G4UrbanMscModel::mscData*> G4UrbanMscModel::msc;
79
80//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
81
82G4UrbanMscModel::G4UrbanMscModel(const G4String& nam)
83 : G4VMscModel(nam)
84{
85 masslimite = 0.6*MeV;
86 fr = 0.02;
87 taubig = 8.0;
88 tausmall = 1.e-16;
89 taulim = 1.e-6;
90 currentTau = taulim;
91 tlimitminfix = 0.01*nm;
92 tlimitminfix2 = 1.*nm;
93 stepmin = tlimitminfix;
94 smallstep = 1.e10;
95 currentRange = 0. ;
96 rangeinit = 0.;
97 tlimit = 1.e10*mm;
98 tlimitmin = 10.*tlimitminfix;
99 tgeom = 1.e50*mm;
100 geombig = 1.e50*mm;
101 geommin = 1.e-3*mm;
102 geomlimit = geombig;
103 presafety = 0.*mm;
104
105 particle = nullptr;
106
107 positron = G4Positron::Positron();
108 theManager = G4LossTableManager::Instance();
109 rndmEngineMod = G4Random::getTheEngine();
110
111 firstStep = true;
112 insideskin = false;
113 latDisplasmentbackup = false;
114 dispAlg96 = true;
115
116 rangecut = geombig;
117 drr = 0.35;
118 finalr = 10.*um;
119
120 tlow = 5.*CLHEP::keV;
121 invmev = 1.0/CLHEP::MeV;
122
123 skindepth = skin*stepmin;
124
125 mass = proton_mass_c2;
126 charge = ChargeSquare = 1.0;
127 currentKinEnergy = currentRadLength = lambda0 = lambdaeff = tPathLength
128 = zPathLength = par1 = par2 = par3 = 0;
129 currentLogKinEnergy = LOG_EKIN_MIN;
130
131 idx = 0;
132 fParticleChange = nullptr;
133 couple = nullptr;
134}
135
136//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
137
138G4UrbanMscModel::~G4UrbanMscModel()
139{
140 if(IsMaster()) {
141 for(auto & ptr : msc) { delete ptr; }
142 msc.clear();
143 }
144}
145
146//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
147
148void G4UrbanMscModel::Initialise(const G4ParticleDefinition* p,
149 const G4DataVector&)
150{
151 // set values of some data members
152 SetParticle(p);
153 fParticleChange = GetParticleChangeForMSC(p);
154 InitialiseParameters(p);
155
156 latDisplasmentbackup = latDisplasment;
157 dispAlg96 = (G4EmParameters::Instance()->LateralDisplacementAlg96());
158 if(IsMaster() || msc.size() == 0) { InitialiseModelCache(); }
159 /*
160 G4cout << "### G4UrbanMscModel::Initialise done for "
161 << p->GetParticleName() << " type= " << steppingAlgorithm << G4endl;
162 G4cout << " RangeFact= " << facrange << " GeomFact= " << facgeom
163 << " SafetyFact= " << facsafety << " LambdaLim= " << lambdalimit
164 << G4endl;
165 */
166}
167
168//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
169
170G4double G4UrbanMscModel::ComputeCrossSectionPerAtom(
171 const G4ParticleDefinition* part,
172 G4double KineticEnergy,
173 G4double AtomicNumber,G4double,
174 G4double, G4double)
175{
176 static const G4double epsmin = 1.e-4 , epsmax = 1.e10;
177
178 static const G4double Zdat[15] = { 4., 6., 13., 20., 26., 29., 32., 38.,47.,
179 50., 56., 64., 74., 79., 82. };
180
181 // corr. factors for e-/e+ lambda for T <= Tlim
182 static const G4double celectron[15][22] =
183 {{1.125,1.072,1.051,1.047,1.047,1.050,1.052,1.054,
184 1.054,1.057,1.062,1.069,1.075,1.090,1.105,1.111,
185 1.112,1.108,1.100,1.093,1.089,1.087 },
186 {1.408,1.246,1.143,1.096,1.077,1.059,1.053,1.051,
187 1.052,1.053,1.058,1.065,1.072,1.087,1.101,1.108,
188 1.109,1.105,1.097,1.090,1.086,1.082 },
189 {2.833,2.268,1.861,1.612,1.486,1.309,1.204,1.156,
190 1.136,1.114,1.106,1.106,1.109,1.119,1.129,1.132,
191 1.131,1.124,1.113,1.104,1.099,1.098 },
192 {3.879,3.016,2.380,2.007,1.818,1.535,1.340,1.236,
193 1.190,1.133,1.107,1.099,1.098,1.103,1.110,1.113,
194 1.112,1.105,1.096,1.089,1.085,1.098 },
195 {6.937,4.330,2.886,2.256,1.987,1.628,1.395,1.265,
196 1.203,1.122,1.080,1.065,1.061,1.063,1.070,1.073,
197 1.073,1.070,1.064,1.059,1.056,1.056 },
198 {9.616,5.708,3.424,2.551,2.204,1.762,1.485,1.330,
199 1.256,1.155,1.099,1.077,1.070,1.068,1.072,1.074,
200 1.074,1.070,1.063,1.059,1.056,1.052 },
201 {11.72,6.364,3.811,2.806,2.401,1.884,1.564,1.386,
202 1.300,1.180,1.112,1.082,1.073,1.066,1.068,1.069,
203 1.068,1.064,1.059,1.054,1.051,1.050 },
204 {18.08,8.601,4.569,3.183,2.662,2.025,1.646,1.439,
205 1.339,1.195,1.108,1.068,1.053,1.040,1.039,1.039,
206 1.039,1.037,1.034,1.031,1.030,1.036 },
207 {18.22,10.48,5.333,3.713,3.115,2.367,1.898,1.631,
208 1.498,1.301,1.171,1.105,1.077,1.048,1.036,1.033,
209 1.031,1.028,1.024,1.022,1.021,1.024 },
210 {14.14,10.65,5.710,3.929,3.266,2.453,1.951,1.669,
211 1.528,1.319,1.178,1.106,1.075,1.040,1.027,1.022,
212 1.020,1.017,1.015,1.013,1.013,1.020 },
213 {14.11,11.73,6.312,4.240,3.478,2.566,2.022,1.720,
214 1.569,1.342,1.186,1.102,1.065,1.022,1.003,0.997,
215 0.995,0.993,0.993,0.993,0.993,1.011 },
216 {22.76,20.01,8.835,5.287,4.144,2.901,2.219,1.855,
217 1.677,1.410,1.224,1.121,1.073,1.014,0.986,0.976,
218 0.974,0.972,0.973,0.974,0.975,0.987 },
219 {50.77,40.85,14.13,7.184,5.284,3.435,2.520,2.059,
220 1.837,1.512,1.283,1.153,1.091,1.010,0.969,0.954,
221 0.950,0.947,0.949,0.952,0.954,0.963 },
222 {65.87,59.06,15.87,7.570,5.567,3.650,2.682,2.182,
223 1.939,1.579,1.325,1.178,1.108,1.014,0.965,0.947,
224 0.941,0.938,0.940,0.944,0.946,0.954 },
225 {55.60,47.34,15.92,7.810,5.755,3.767,2.760,2.239,
226 1.985,1.609,1.343,1.188,1.113,1.013,0.960,0.939,
227 0.933,0.930,0.933,0.936,0.939,0.949 }};
228
229 static const G4double cpositron[15][22] = {
230 {2.589,2.044,1.658,1.446,1.347,1.217,1.144,1.110,
231 1.097,1.083,1.080,1.086,1.092,1.108,1.123,1.131,
232 1.131,1.126,1.117,1.108,1.103,1.100 },
233 {3.904,2.794,2.079,1.710,1.543,1.325,1.202,1.145,
234 1.122,1.096,1.089,1.092,1.098,1.114,1.130,1.137,
235 1.138,1.132,1.122,1.113,1.108,1.102 },
236 {7.970,6.080,4.442,3.398,2.872,2.127,1.672,1.451,
237 1.357,1.246,1.194,1.179,1.178,1.188,1.201,1.205,
238 1.203,1.190,1.173,1.159,1.151,1.145 },
239 {9.714,7.607,5.747,4.493,3.815,2.777,2.079,1.715,
240 1.553,1.353,1.253,1.219,1.211,1.214,1.225,1.228,
241 1.225,1.210,1.191,1.175,1.166,1.174 },
242 {17.97,12.95,8.628,6.065,4.849,3.222,2.275,1.820,
243 1.624,1.382,1.259,1.214,1.202,1.202,1.214,1.219,
244 1.217,1.203,1.184,1.169,1.160,1.151 },
245 {24.83,17.06,10.84,7.355,5.767,3.707,2.546,1.996,
246 1.759,1.465,1.311,1.252,1.234,1.228,1.238,1.241,
247 1.237,1.222,1.201,1.184,1.174,1.159 },
248 {23.26,17.15,11.52,8.049,6.375,4.114,2.792,2.155,
249 1.880,1.535,1.353,1.281,1.258,1.247,1.254,1.256,
250 1.252,1.234,1.212,1.194,1.183,1.170 },
251 {22.33,18.01,12.86,9.212,7.336,4.702,3.117,2.348,
252 2.015,1.602,1.385,1.297,1.268,1.251,1.256,1.258,
253 1.254,1.237,1.214,1.195,1.185,1.179 },
254 {33.91,24.13,15.71,10.80,8.507,5.467,3.692,2.808,
255 2.407,1.873,1.564,1.425,1.374,1.330,1.324,1.320,
256 1.312,1.288,1.258,1.235,1.221,1.205 },
257 {32.14,24.11,16.30,11.40,9.015,5.782,3.868,2.917,
258 2.490,1.925,1.596,1.447,1.391,1.342,1.332,1.327,
259 1.320,1.294,1.264,1.240,1.226,1.214 },
260 {29.51,24.07,17.19,12.28,9.766,6.238,4.112,3.066,
261 2.602,1.995,1.641,1.477,1.414,1.356,1.342,1.336,
262 1.328,1.302,1.270,1.245,1.231,1.233 },
263 {38.19,30.85,21.76,15.35,12.07,7.521,4.812,3.498,
264 2.926,2.188,1.763,1.563,1.484,1.405,1.382,1.371,
265 1.361,1.330,1.294,1.267,1.251,1.239 },
266 {49.71,39.80,27.96,19.63,15.36,9.407,5.863,4.155,
267 3.417,2.478,1.944,1.692,1.589,1.480,1.441,1.423,
268 1.409,1.372,1.330,1.298,1.280,1.258 },
269 {59.25,45.08,30.36,20.83,16.15,9.834,6.166,4.407,
270 3.641,2.648,2.064,1.779,1.661,1.531,1.482,1.459,
271 1.442,1.400,1.354,1.319,1.299,1.272 },
272 {56.38,44.29,30.50,21.18,16.51,10.11,6.354,4.542,
273 3.752,2.724,2.116,1.817,1.692,1.554,1.499,1.474,
274 1.456,1.412,1.364,1.328,1.307,1.282 }};
275
276 //data/corrections for T > Tlim
277
278 static const G4double hecorr[15] = {
279 120.70, 117.50, 105.00, 92.92, 79.23, 74.510, 68.29,
280 57.39, 41.97, 36.14, 24.53, 10.21, -7.855, -16.84,
281 -22.30};
282
283 G4double sigma;
284 SetParticle(part);
285
286 G4double Z23 = G4Pow::GetInstance()->Z23(G4lrint(AtomicNumber));
287
288 // correction if particle .ne. e-/e+
289 // compute equivalent kinetic energy
290 // lambda depends on p*beta ....
291
292 G4double eKineticEnergy = KineticEnergy;
293
294 if(mass > electron_mass_c2)
295 {
296 G4double TAU = KineticEnergy/mass ;
297 G4double c = mass*TAU*(TAU+2.)/(electron_mass_c2*(TAU+1.)) ;
298 G4double w = c-2. ;
299 G4double tau = 0.5*(w+sqrt(w*w+4.*c)) ;
300 eKineticEnergy = electron_mass_c2*tau ;
301 }
302
303 G4double eTotalEnergy = eKineticEnergy + electron_mass_c2 ;
304 G4double beta2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2)
305 /(eTotalEnergy*eTotalEnergy);
306 G4double bg2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2)
307 /(electron_mass_c2*electron_mass_c2);
308
309 static const G4double epsfactor = 2.*CLHEP::electron_mass_c2*
310 CLHEP::electron_mass_c2*CLHEP::Bohr_radius*CLHEP::Bohr_radius
311 /(CLHEP::hbarc*CLHEP::hbarc);
312 G4double eps = epsfactor*bg2/Z23;
313
314 if (eps<epsmin) sigma = 2.*eps*eps;
315 else if(eps<epsmax) sigma = G4Log(1.+2.*eps)-2.*eps/(1.+2.*eps);
316 else sigma = G4Log(2.*eps)-1.+1./eps;
317
318 sigma *= ChargeSquare*AtomicNumber*AtomicNumber/(beta2*bg2);
319
320 // interpolate in AtomicNumber and beta2
321 G4double c1,c2,cc1,cc2,corr;
322
323 // get bin number in Z
324 G4int iZ = 14;
325 // Loop checking, 03-Aug-2015, Vladimir Ivanchenko
326 while ((iZ>=0)&&(Zdat[iZ]>=AtomicNumber)) iZ -= 1;
327
328 iZ = std::min(std::max(iZ, 0), 13);
329
330 G4double ZZ1 = Zdat[iZ];
331 G4double ZZ2 = Zdat[iZ+1];
332 G4double ratZ = (AtomicNumber-ZZ1)*(AtomicNumber+ZZ1)/
333 ((ZZ2-ZZ1)*(ZZ2+ZZ1));
334
335 static const G4double Tlim = 10.*CLHEP::MeV;
336 static const G4double sigmafactor =
337 CLHEP::twopi*CLHEP::classic_electr_radius*CLHEP::classic_electr_radius;
338 static const G4double beta2lim = Tlim*(Tlim+2.*CLHEP::electron_mass_c2)/
339 ((Tlim+CLHEP::electron_mass_c2)*(Tlim+CLHEP::electron_mass_c2));
340 static const G4double bg2lim = Tlim*(Tlim+2.*CLHEP::electron_mass_c2)/
341 (CLHEP::electron_mass_c2*CLHEP::electron_mass_c2);
342
343 static const G4double sig0[15] = {
344 0.2672*CLHEP::barn, 0.5922*CLHEP::barn, 2.653*CLHEP::barn, 6.235*CLHEP::barn,
345 11.69*CLHEP::barn , 13.24*CLHEP::barn , 16.12*CLHEP::barn, 23.00*CLHEP::barn,
346 35.13*CLHEP::barn , 39.95*CLHEP::barn , 50.85*CLHEP::barn, 67.19*CLHEP::barn,
347 91.15*CLHEP::barn , 104.4*CLHEP::barn , 113.1*CLHEP::barn};
348
349 static const G4double Tdat[22] = {
350 100*CLHEP::eV, 200*CLHEP::eV, 400*CLHEP::eV, 700*CLHEP::eV,
351 1*CLHEP::keV, 2*CLHEP::keV, 4*CLHEP::keV, 7*CLHEP::keV,
352 10*CLHEP::keV, 20*CLHEP::keV, 40*CLHEP::keV, 70*CLHEP::keV,
353 100*CLHEP::keV, 200*CLHEP::keV, 400*CLHEP::keV, 700*CLHEP::keV,
354 1*CLHEP::MeV, 2*CLHEP::MeV, 4*CLHEP::MeV, 7*CLHEP::MeV,
355 10*CLHEP::MeV, 20*CLHEP::MeV};
356
357 if(eKineticEnergy <= Tlim)
358 {
359 // get bin number in T (beta2)
360 G4int iT = 21;
361 // Loop checking, 03-Aug-2015, Vladimir Ivanchenko
362 while ((iT>=0)&&(Tdat[iT]>=eKineticEnergy)) iT -= 1;
363
364 iT = std::min(std::max(iT, 0), 20);
365
366 // calculate betasquare values
367 G4double T = Tdat[iT], E = T + electron_mass_c2;
368 G4double b2small = T*(E+electron_mass_c2)/(E*E);
369
370 T = Tdat[iT+1]; E = T + electron_mass_c2;
371 G4double b2big = T*(E+electron_mass_c2)/(E*E);
372 G4double ratb2 = (beta2-b2small)/(b2big-b2small);
373
374 if (charge < 0.)
375 {
376 c1 = celectron[iZ][iT];
377 c2 = celectron[iZ+1][iT];
378 cc1 = c1+ratZ*(c2-c1);
379
380 c1 = celectron[iZ][iT+1];
381 c2 = celectron[iZ+1][iT+1];
382 cc2 = c1+ratZ*(c2-c1);
383
384 corr = cc1+ratb2*(cc2-cc1);
385
386 sigma *= sigmafactor/corr;
387 }
388 else
389 {
390 c1 = cpositron[iZ][iT];
391 c2 = cpositron[iZ+1][iT];
392 cc1 = c1+ratZ*(c2-c1);
393
394 c1 = cpositron[iZ][iT+1];
395 c2 = cpositron[iZ+1][iT+1];
396 cc2 = c1+ratZ*(c2-c1);
397
398 corr = cc1+ratb2*(cc2-cc1);
399
400 sigma *= sigmafactor/corr;
401 }
402 }
403 else
404 {
405 c1 = bg2lim*sig0[iZ]*(1.+hecorr[iZ]*(beta2-beta2lim))/bg2;
406 c2 = bg2lim*sig0[iZ+1]*(1.+hecorr[iZ+1]*(beta2-beta2lim))/bg2;
407 if((AtomicNumber >= ZZ1) && (AtomicNumber <= ZZ2))
408 sigma = c1+ratZ*(c2-c1) ;
409 else if(AtomicNumber < ZZ1)
410 sigma = AtomicNumber*AtomicNumber*c1/(ZZ1*ZZ1);
411 else if(AtomicNumber > ZZ2)
412 sigma = AtomicNumber*AtomicNumber*c2/(ZZ2*ZZ2);
413 }
414 // low energy correction based on theory
415 sigma *= 1.+0.30/(1.+sqrt(1000.*eKineticEnergy));
416
417 return sigma;
418
419}
420
421//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
422
423void G4UrbanMscModel::StartTracking(G4Track* track)
424{
425 SetParticle(track->GetDynamicParticle()->GetDefinition());
426 firstStep = true;
427 insideskin = false;
428 fr = facrange;
429 tlimit = tgeom = rangeinit = rangecut = geombig;
430 smallstep = 1.e10;
431 stepmin = tlimitminfix;
432 tlimitmin = 10.*tlimitminfix;
433 rndmEngineMod = G4Random::getTheEngine();
434}
435
436//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
437
438G4double G4UrbanMscModel::ComputeTruePathLengthLimit(
439 const G4Track& track,
440 G4double& currentMinimalStep)
441{
442 tPathLength = currentMinimalStep;
443 const G4DynamicParticle* dp = track.GetDynamicParticle();
444
445 G4StepPoint* sp = track.GetStep()->GetPreStepPoint();
446 G4StepStatus stepStatus = sp->GetStepStatus();
447 couple = track.GetMaterialCutsCouple();
448 SetCurrentCouple(couple);
449 idx = couple->GetIndex();
450 currentKinEnergy = dp->GetKineticEnergy();
451 currentLogKinEnergy = dp->GetLogKineticEnergy();
452 currentRange = GetRange(particle,currentKinEnergy,couple,currentLogKinEnergy);
453 lambda0 = GetTransportMeanFreePath(particle,currentKinEnergy,
454 currentLogKinEnergy);
455 tPathLength = std::min(tPathLength,currentRange);
456 /*
457 G4cout << "G4Urban::StepLimit tPathLength= " << tPathLength
458 << " range= " <<currentRange<< " lambda= "<<lambda0
459 <<G4endl;
460 */
461
462 // stop here if small step
463 if(tPathLength < tlimitminfix) {
464 latDisplasment = false;
465 return ConvertTrueToGeom(tPathLength, currentMinimalStep);
466 }
467
468 // upper limit for the straight line distance the particle can travel
469 // for electrons and positrons
470 G4double distance = (mass < masslimite)
471 ? currentRange*msc[idx]->doverra
472 // for muons, hadrons
473 : currentRange*msc[idx]->doverrb;
474
475 presafety = sp->GetSafety();
476 /*
477 G4cout << "G4Urban::StepLimit tPathLength= "
478 <<tPathLength<<" safety= " << presafety
479 << " range= " <<currentRange<< " lambda= "<<lambda0
480 << " Alg: " << steppingAlgorithm <<G4endl;
481 */
482 // far from geometry boundary
483 if(distance < presafety)
484 {
485 latDisplasment = false;
486 return ConvertTrueToGeom(tPathLength, currentMinimalStep);
487 }
488
489 latDisplasment = latDisplasmentbackup;
490 // standard version
491 //
492 if (steppingAlgorithm == fUseDistanceToBoundary)
493 {
494 //compute geomlimit and presafety
495 geomlimit = ComputeGeomLimit(track, presafety, currentRange);
496 /*
497 G4cout << "G4Urban::Distance to boundary geomlimit= "
498 <<geomlimit<<" safety= " << presafety<<G4endl;
499 */
500
501 // is it far from boundary ?
502 if(distance < presafety)
503 {
504 latDisplasment = false;
505 return ConvertTrueToGeom(tPathLength, currentMinimalStep);
506 }
507
508 smallstep += 1.;
509 insideskin = false;
510
511 // initialisation at firs step and at the boundary
512 if(firstStep || (stepStatus == fGeomBoundary))
513 {
514 rangeinit = currentRange;
515 if(!firstStep) { smallstep = 1.; }
516
517 //stepmin ~ lambda_elastic
518 stepmin = ComputeStepmin();
519 skindepth = skin*stepmin;
520 tlimitmin = ComputeTlimitmin();
521 /*
522 G4cout << "rangeinit= " << rangeinit << " stepmin= " << stepmin
523 << " tlimitmin= " << tlimitmin << " geomlimit= "
524 << geomlimit <<G4endl;
525 */
526 // constraint from the geometry
527
528 if((geomlimit < geombig) && (geomlimit > geommin))
529 {
530 // geomlimit is a geometrical step length
531 // transform it to true path length (estimation)
532 if(lambda0 > geomlimit) {
533 geomlimit = -lambda0*G4Log(1.-geomlimit/lambda0)+tlimitmin;
534 }
535 tgeom = (stepStatus == fGeomBoundary)
536 ? geomlimit/facgeom : 2.*geomlimit/facgeom;
537 }
538 else
539 {
540 tgeom = geombig;
541 }
542 }
543
544 //step limit
545 tlimit = (currentRange > presafety) ?
546 std::max(facrange*rangeinit, facsafety*presafety) : currentRange;
547
548 //lower limit for tlimit
549 tlimit = std::min(std::max(tlimit,tlimitmin), tgeom);
550 /*
551 G4cout << "tgeom= " << tgeom << " geomlimit= " << geomlimit
552 << " tlimit= " << tlimit << " presafety= " << presafety << G4endl;
553 */
554 // shortcut
555 if((tPathLength < tlimit) && (tPathLength < presafety) &&
556 (smallstep > skin) && (tPathLength < geomlimit-0.999*skindepth))
557 {
558 return ConvertTrueToGeom(tPathLength, currentMinimalStep);
559 }
560
561 // step reduction near to boundary
562 if(smallstep <= skin)
563 {
564 tlimit = stepmin;
565 insideskin = true;
566 }
567 else if(geomlimit < geombig)
568 {
569 if(geomlimit > skindepth)
570 {
571 tlimit = std::min(tlimit, geomlimit-0.999*skindepth);
572 }
573 else
574 {
575 insideskin = true;
576 tlimit = std::min(tlimit, stepmin);
577 }
578 }
579
580 tlimit = std::max(tlimit, stepmin);
581
582 // randomise if not 'small' step and step determined by msc
583 tPathLength = ((tlimit < tPathLength)&&(smallstep > skin)&& !insideskin)
584 ? std::min(tPathLength, Randomizetlimit())
585 : std::min(tPathLength, tlimit);
586 }
587 // for 'normal' simulation with or without magnetic field
588 // there no small step/single scattering at boundaries
589 else if(steppingAlgorithm == fUseSafety)
590 {
591 if(stepStatus != fGeomBoundary) {
592 presafety = ComputeSafety(sp->GetPosition(),tPathLength);
593 }
594 /*
595 G4cout << "presafety= " << presafety
596 << " firstStep= " << firstStep
597 << " stepStatus= " << stepStatus
598 << G4endl;
599 */
600 // is far from boundary
601 if(distance < presafety)
602 {
603 latDisplasment = false;
604 return ConvertTrueToGeom(tPathLength, currentMinimalStep);
605 }
606
607 if(firstStep || (stepStatus == fGeomBoundary)) {
608 rangeinit = currentRange;
609 fr = facrange;
610 // 9.1 like stepping for e+/e- only (not for muons,hadrons)
611 if(mass < masslimite)
612 {
613 rangeinit = std::max(rangeinit, lambda0);
614 if(lambda0 > lambdalimit) {
615 fr *= (0.75+0.25*lambda0/lambdalimit);
616 }
617 }
618 //lower limit for tlimit
619 stepmin = ComputeStepmin();
620 tlimitmin = ComputeTlimitmin();
621 }
622
623 //step limit
624 tlimit = (currentRange > presafety) ?
625 std::max(fr*rangeinit, facsafety*presafety) : currentRange;
626
627 //lower limit for tlimit
628 tlimit = std::max(tlimit, tlimitmin);
629
630 // randomise if step determined by msc
631 tPathLength = (tlimit < tPathLength) ?
632 std::min(tPathLength, Randomizetlimit()) : tPathLength;
633 }
634 // new stepping mode UseSafetyPlus
635 else if(steppingAlgorithm == fUseSafetyPlus)
636 {
637 if(stepStatus != fGeomBoundary) {
638 presafety = ComputeSafety(sp->GetPosition(),tPathLength);
639 }
640 /*
641 G4cout << "presafety= " << presafety
642 << " firstStep= " << firstStep
643 << " stepStatus= " << stepStatus
644 << G4endl;
645 */
646 // is far from boundary
647 if(distance < presafety)
648 {
649 latDisplasment = false;
650 return ConvertTrueToGeom(tPathLength, currentMinimalStep);
651 }
652
653 if(firstStep || (stepStatus == fGeomBoundary)) {
654 rangeinit = currentRange;
655 fr = facrange;
656 rangecut = geombig;
657 if(mass < masslimite)
658 {
659 rangecut = msc[idx]->ecut;
660 if(lambda0 > lambdalimit) {
661 fr *= (0.84+0.16*lambda0/lambdalimit);
662 }
663 }
664 //lower limit for tlimit
665 stepmin = ComputeStepmin();
666 tlimitmin = ComputeTlimitmin();
667 }
668 //step limit
669 tlimit = (currentRange > presafety) ?
670 std::max(fr*rangeinit, facsafety*presafety) : currentRange;
671
672 //lower limit for tlimit
673 tlimit = std::max(tlimit, tlimitmin);
674
675 // condition for tPathLength from drr and finalr
676 if(currentRange > finalr) {
677 G4double tmax = drr*currentRange+
678 finalr*(1.-drr)*(2.-finalr/currentRange);
679 tPathLength = std::min(tPathLength,tmax);
680 }
681
682 // condition safety
683 if(currentRange > rangecut) {
684 if(firstStep) {
685 tPathLength = std::min(tPathLength,facsafety*presafety);
686 } else if(stepStatus != fGeomBoundary && presafety > stepmin) {
687 tPathLength = std::min(tPathLength,presafety);
688 }
689 }
690
691 // randomise if step determined by msc
692 tPathLength = (tlimit < tPathLength) ?
693 std::min(tPathLength, Randomizetlimit()) : tPathLength;
694 }
695
696 // simple step limitation
697 else
698 {
699 if (stepStatus == fGeomBoundary)
700 {
701 tlimit = (currentRange > lambda0)
702 ? facrange*currentRange : facrange*lambda0;
703 tlimit = std::max(tlimit, tlimitmin);
704 }
705 // randomise if step determined by msc
706 tPathLength = (tlimit < tPathLength) ?
707 std::min(tPathLength, Randomizetlimit()) : tPathLength;
708 }
709 firstStep = false;
710 return ConvertTrueToGeom(tPathLength, currentMinimalStep);
711}
712
713//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
714
715G4double G4UrbanMscModel::ComputeGeomPathLength(G4double)
716{
717 lambdaeff = lambda0;
718 par1 = -1. ;
719 par2 = par3 = 0. ;
720
721 // this correction needed to run MSC with eIoni and eBrem inactivated
722 // and makes no harm for a normal run
723 tPathLength = std::min(tPathLength,currentRange);
724
725 // do the true -> geom transformation
726 zPathLength = tPathLength;
727
728 // z = t for very small tPathLength
729 if(tPathLength < tlimitminfix2) return zPathLength;
730
731 /*
732 G4cout << "ComputeGeomPathLength: tpl= " << tPathLength
733 << " R= " << currentRange << " L0= " << lambda0
734 << " E= " << currentKinEnergy << " "
735 << particle->GetParticleName() << G4endl;
736 */
737 G4double tau = tPathLength/lambda0 ;
738
739 if ((tau <= tausmall) || insideskin) {
740 zPathLength = std::min(tPathLength, lambda0);
741
742 } else if (tPathLength < currentRange*dtrl) {
743 if(tau < taulim) zPathLength = tPathLength*(1.-0.5*tau) ;
744 else zPathLength = lambda0*(1.-G4Exp(-tau));
745
746 } else if(currentKinEnergy < mass || tPathLength == currentRange) {
747 par1 = 1./currentRange ;
748 par2 = 1./(par1*lambda0) ;
749 par3 = 1.+par2 ;
750 if(tPathLength < currentRange) {
751 zPathLength =
752 (1.-G4Exp(par3*G4Log(1.-tPathLength/currentRange)))/(par1*par3);
753 } else {
754 zPathLength = 1./(par1*par3);
755 }
756
757 } else {
758 G4double rfin = std::max(currentRange-tPathLength, 0.01*currentRange);
759 G4double T1 = GetEnergy(particle,rfin,couple);
760 G4double lambda1 = GetTransportMeanFreePath(particle,T1);
761
762 par1 = (lambda0-lambda1)/(lambda0*tPathLength);
763 //G4cout << "par1= " << par1 << " L1= " << lambda1 << G4endl;
764 par2 = 1./(par1*lambda0);
765 par3 = 1.+par2 ;
766 zPathLength = (1.-G4Exp(par3*G4Log(lambda1/lambda0)))/(par1*par3);
767 }
768
769 zPathLength = std::min(zPathLength, lambda0);
770 //G4cout<< "zPathLength= "<< zPathLength<< " L0= " << lambda0 << G4endl;
771 return zPathLength;
772}
773
774//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
775
776G4double G4UrbanMscModel::ComputeTrueStepLength(G4double geomStepLength)
777{
778 // step defined other than transportation
779 if(geomStepLength == zPathLength) {
780 //G4cout << "Urban::ComputeTrueLength: tPathLength= " << tPathLength
781 // << " step= " << geomStepLength << " *** " << G4endl;
782 return tPathLength;
783 }
784
785 zPathLength = geomStepLength;
786
787 // t = z for very small step
788 if(geomStepLength < tlimitminfix2) {
789 tPathLength = geomStepLength;
790
791 // recalculation
792 } else {
793
794 G4double tlength = geomStepLength;
795 if((geomStepLength > lambda0*tausmall) && !insideskin) {
796
797 if(par1 < 0.) {
798 tlength = -lambda0*G4Log(1.-geomStepLength/lambda0) ;
799 } else {
800 if(par1*par3*geomStepLength < 1.) {
801 tlength = (1.-G4Exp(G4Log(1.-par1*par3*geomStepLength)/par3))/par1 ;
802 } else {
803 tlength = currentRange;
804 }
805 }
806
807 if(tlength < geomStepLength) { tlength = geomStepLength; }
808 else if(tlength > tPathLength) { tlength = tPathLength; }
809 }
810 tPathLength = tlength;
811 }
812 //G4cout << "Urban::ComputeTrueLength: tPathLength= " << tPathLength
813 // << " step= " << geomStepLength << " &&& " << G4endl;
814
815 return tPathLength;
816}
817
818//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
819
820G4ThreeVector&
821G4UrbanMscModel::SampleScattering(const G4ThreeVector& oldDirection,
822 G4double /*safety*/)
823{
824 fDisplacement.set(0.0,0.0,0.0);
825 G4double kineticEnergy = currentKinEnergy;
826 if (tPathLength > currentRange*dtrl) {
827 kineticEnergy = GetEnergy(particle,currentRange-tPathLength,couple);
828 } else {
829 kineticEnergy -= tPathLength*GetDEDX(particle,currentKinEnergy,couple,
830 currentLogKinEnergy);
831 }
832
833 if((kineticEnergy <= eV) || (tPathLength <= tlimitminfix) ||
834 (tPathLength < tausmall*lambda0)) { return fDisplacement; }
835
836 G4double cth = SampleCosineTheta(tPathLength,kineticEnergy);
837
838 // protection against 'bad' cth values
839 if(std::abs(cth) >= 1.0) { return fDisplacement; }
840
841 /*
842 if(cth < 1.0 - 1000*tPathLength/lambda0 && cth < 0.5 &&
843 kineticEnergy > 20*MeV) {
844 G4cout << "### G4UrbanMscModel::SampleScattering for "
845 << particle->GetParticleName()
846 << " E(MeV)= " << kineticEnergy/MeV
847 << " Step(mm)= " << tPathLength/mm
848 << " in " << CurrentCouple()->GetMaterial()->GetName()
849 << " CosTheta= " << cth << G4endl;
850 }
851 */
852 G4double sth = sqrt((1.0 - cth)*(1.0 + cth));
853 G4double phi = twopi*rndmEngineMod->flat();
854 G4double dirx = sth*cos(phi);
855 G4double diry = sth*sin(phi);
856
857 G4ThreeVector newDirection(dirx,diry,cth);
858 newDirection.rotateUz(oldDirection);
859
860 fParticleChange->ProposeMomentumDirection(newDirection);
861 /*
862 G4cout << "G4UrbanMscModel::SampleSecondaries: e(MeV)= " << kineticEnergy
863 << " sinTheta= " << sth << " safety(mm)= " << safety
864 << " trueStep(mm)= " << tPathLength
865 << " geomStep(mm)= " << zPathLength
866 << G4endl;
867 */
868
869 if (latDisplasment && currentTau >= tausmall) {
870 if(dispAlg96) { SampleDisplacement(sth, phi); }
871 else { SampleDisplacementNew(cth, phi); }
872 fDisplacement.rotateUz(oldDirection);
873 }
874 return fDisplacement;
875}
876
877//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
878
879G4double G4UrbanMscModel::SampleCosineTheta(G4double trueStepLength,
880 G4double KineticEnergy)
881{
882 G4double cth = 1. ;
883 G4double tau = trueStepLength/lambda0;
884 currentTau = tau;
885 lambdaeff = lambda0;
886
887 G4double lambda1 = GetTransportMeanFreePath(particle,KineticEnergy);
888 if(std::abs(lambda1 - lambda0) > lambda0*0.01 && lambda1 > 0.)
889 {
890 // mean tau value
891 tau = trueStepLength*G4Log(lambda0/lambda1)/(lambda0-lambda1);
892 }
893
894 currentTau = tau ;
895 lambdaeff = trueStepLength/currentTau;
896 currentRadLength = couple->GetMaterial()->GetRadlen();
897
898 if (tau >= taubig) { cth = -1.+2.*rndmEngineMod->flat(); }
899 else if (tau >= tausmall) {
900 static const G4double numlim = 0.01;
901 static const G4double onethird = 1./3.;
902 G4double xmeanth, x2meanth;
903 if(tau < numlim) {
904 xmeanth = 1.0 - tau*(1.0 - 0.5*tau);
905 x2meanth= 1.0 - tau*(5.0 - 6.25*tau)*onethird;
906 } else {
907 xmeanth = G4Exp(-tau);
908 x2meanth = (1.+2.*G4Exp(-2.5*tau))*onethird;
909 }
910
911 // too large step of low-energy particle
912 G4double relloss = 1. - KineticEnergy/currentKinEnergy;
913 static const G4double rellossmax= 0.50;
914 if(relloss > rellossmax) {
915 return SimpleScattering(xmeanth,x2meanth);
916 }
917 // is step extreme small ?
918 G4bool extremesmallstep = false;
919 G4double tsmall = std::min(tlimitmin,lambdalimit);
920 G4double theta0 = 0.;
921 if(trueStepLength > tsmall) {
922 theta0 = ComputeTheta0(trueStepLength,KineticEnergy);
923 } else {
924 theta0 = sqrt(trueStepLength/tsmall)*ComputeTheta0(tsmall,KineticEnergy);
925 extremesmallstep = true ;
926 }
927
928 static const G4double onesixth = 1./6.;
929 static const G4double theta0max = CLHEP::pi*onesixth;
930 //G4cout << "Theta0= " << theta0 << " theta0max= " << theta0max
931 // << " sqrt(tausmall)= " << sqrt(tausmall) << G4endl;
932
933 // protection for very small angles
934 G4double theta2 = theta0*theta0;
935
936 if(theta2 < tausmall) { return cth; }
937
938 if(theta0 > theta0max) {
939 return SimpleScattering(xmeanth,x2meanth);
940 }
941
942 G4double x = theta2*(1.0 - theta2/12.);
943 if(theta2 > numlim) {
944 G4double sth = 2*sin(0.5*theta0);
945 x = sth*sth;
946 }
947
948 // parameter for tail
949 G4double ltau= G4Log(tau);
950 G4double u = extremesmallstep
951 ? G4Exp(G4Log(tsmall/lambda0)*onesixth)
952 : G4Exp(ltau*onesixth);
953 G4double xx = G4Log(lambdaeff/currentRadLength);
954 G4double xsi = msc[idx]->coeffc1 +
955 u*(msc[idx]->coeffc2+msc[idx]->coeffc3*u)+msc[idx]->coeffc4*xx;
956
957 // tail should not be too big
958 xsi = std::max(xsi, 1.9);
959 /*
960 if(KineticEnergy > 20*MeV && xsi < 1.6) {
961 G4cout << "G4UrbanMscModel::SampleCosineTheta: E(GeV)= "
962 << KineticEnergy/GeV
963 << " !!** c= " << xsi
964 << " **!! length(mm)= " << trueStepLength << " Zeff= " << Zeff
965 << " " << couple->GetMaterial()->GetName()
966 << " tau= " << tau << G4endl;
967 }
968 */
969
970 G4double c = xsi;
971
972 if(std::abs(c-3.) < 0.001) { c = 3.001; }
973 else if(std::abs(c-2.) < 0.001) { c = 2.001; }
974
975 G4double c1 = c-1.;
976
977 G4double ea = G4Exp(-xsi);
978 G4double eaa = 1.-ea ;
979 G4double xmean1 = 1.-(1.-(1.+xsi)*ea)*x/eaa;
980 G4double x0 = 1. - xsi*x;
981
982 // G4cout << " xmean1= " << xmean1 << " xmeanth= " << xmeanth << G4endl;
983
984 if(xmean1 <= 0.999*xmeanth) {
985 return SimpleScattering(xmeanth,x2meanth);
986 }
987 //from continuity of derivatives
988 G4double b = 1.+(c-xsi)*x;
989
990 G4double b1 = b+1.;
991 G4double bx = c*x;
992
993 G4double eb1 = G4Exp(G4Log(b1)*c1);
994 G4double ebx = G4Exp(G4Log(bx)*c1);
995 G4double d = ebx/eb1;
996
997 G4double xmean2 = (x0 + d - (bx - b1*d)/(c-2.))/(1. - d);
998
999 G4double f1x0 = ea/eaa;
1000 G4double f2x0 = c1/(c*(1. - d));
1001 G4double prob = f2x0/(f1x0+f2x0);
1002
1003 G4double qprob = xmeanth/(prob*xmean1+(1.-prob)*xmean2);
1004
1005 // sampling of costheta
1006 //G4cout << "c= " << c << " qprob= " << qprob << " eb1= " << eb1
1007 // << " c1= " << c1 << " b1= " << b1 << " bx= " << bx << " eb1= " << eb1
1008 // << G4endl;
1009 if(rndmEngineMod->flat() < qprob)
1010 {
1011 G4double var = 0;
1012 if(rndmEngineMod->flat() < prob) {
1013 cth = 1.+G4Log(ea+rndmEngineMod->flat()*eaa)*x;
1014 } else {
1015 var = (1.0 - d)*rndmEngineMod->flat();
1016 if(var < numlim*d) {
1017 var /= (d*c1);
1018 cth = -1.0 + var*(1.0 - 0.5*var*c)*(2. + (c - xsi)*x);
1019 } else {
1020 cth = 1. + x*(c - xsi - c*G4Exp(-G4Log(var + d)/c1));
1021 }
1022 }
1023 /*
1024 if(KineticEnergy > 5*GeV && cth < 0.9) {
1025 G4cout << "G4UrbanMscModel::SampleCosineTheta: E(GeV)= "
1026 << KineticEnergy/GeV
1027 << " 1-cosT= " << 1 - cth
1028 << " length(mm)= " << trueStepLength << " Zeff= " << Zeff
1029 << " tau= " << tau
1030 << " prob= " << prob << " var= " << var << G4endl;
1031 G4cout << " c= " << c << " qprob= " << qprob << " eb1= " << eb1
1032 << " ebx= " << ebx
1033 << " c1= " << c1 << " b= " << b << " b1= " << b1
1034 << " bx= " << bx << " d= " << d
1035 << " ea= " << ea << " eaa= " << eaa << G4endl;
1036 }
1037 */
1038 }
1039 else {
1040 cth = -1.+2.*rndmEngineMod->flat();
1041 /*
1042 if(KineticEnergy > 5*GeV) {
1043 G4cout << "G4UrbanMscModel::SampleCosineTheta: E(GeV)= "
1044 << KineticEnergy/GeV
1045 << " length(mm)= " << trueStepLength << " Zeff= " << Zeff
1046 << " qprob= " << qprob << G4endl;
1047 }
1048 */
1049 }
1050 }
1051 return cth ;
1052}
1053
1054//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
1055
1056G4double G4UrbanMscModel::ComputeTheta0(G4double trueStepLength,
1057 G4double KineticEnergy)
1058{
1059 // for all particles take the width of the central part
1060 // from a parametrization similar to the Highland formula
1061 // ( Highland formula: Particle Physics Booklet, July 2002, eq. 26.10)
1062 G4double invbetacp = std::sqrt((currentKinEnergy+mass)*(KineticEnergy+mass)/
1063 (currentKinEnergy*(currentKinEnergy+2.*mass)*
1064 KineticEnergy*(KineticEnergy+2.*mass)));
1065 G4double y = trueStepLength/currentRadLength;
1066
1067 if(particle == positron)
1068 {
1069 G4double Zeff = msc[idx]->Zeff;
1070 static const G4double xl= 0.6;
1071 static const G4double xh= 0.9;
1072 static const G4double e = 113.0;
1073 G4double corr;
1074
1075 G4double tau = std::sqrt(currentKinEnergy*KineticEnergy)/mass;
1076 G4double x = std::sqrt(tau*(tau+2.)/((tau+1.)*(tau+1.)));
1077 G4double a = 0.994-4.08e-3*Zeff;
1078 G4double b = 7.16+(52.6+365./Zeff)/Zeff;
1079 G4double c = 1.000-4.47e-3*Zeff;
1080 G4double d = 1.21e-3*Zeff;
1081 if(x < xl) {
1082 corr = a*(1.-G4Exp(-b*x));
1083 } else if(x > xh) {
1084 corr = c+d*G4Exp(e*(x-1.));
1085 } else {
1086 G4double yl = a*(1.-G4Exp(-b*xl));
1087 G4double yh = c+d*G4Exp(e*(xh-1.));
1088 G4double y0 = (yh-yl)/(xh-xl);
1089 G4double y1 = yl-y0*xl;
1090 corr = y0*x+y1;
1091 }
1092 //==================================================================
1093 y *= corr*(1.+Zeff*(1.84035e-4*Zeff-1.86427e-2)+0.41125);
1094 }
1095
1096 static const G4double c_highland = 13.6*CLHEP::MeV;
1097 G4double theta0 = c_highland*std::abs(charge)*std::sqrt(y)*invbetacp;
1098
1099 // correction factor from e- scattering data
1100 theta0 *= (msc[idx]->coeffth1+msc[idx]->coeffth2*G4Log(y));
1101 return theta0;
1102}
1103
1104//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
1105
1106void G4UrbanMscModel::SampleDisplacement(G4double, G4double phi)
1107{
1108 // simple and fast sampling
1109 // based on single scattering results
1110 // u = r/rmax : mean value
1111
1112 G4double rmax = sqrt((tPathLength-zPathLength)*(tPathLength+zPathLength));
1113 if(rmax > 0.)
1114 {
1115 G4double r = 0.73*rmax;
1116
1117 // simple distribution for v=Phi-phi=psi ~exp(-beta*v)
1118 // beta determined from the requirement that distribution should give
1119 // the same mean value than that obtained from the ss simulation
1120
1121 static const G4double cbeta = 2.160;
1122 static const G4double cbeta1 = 1.-G4Exp(-cbeta*CLHEP::pi);
1123 G4double psi = -G4Log(1.-rndmEngineMod->flat()*cbeta1)/cbeta;
1124 G4double Phi = (rndmEngineMod->flat() < 0.5) ? phi+psi : phi-psi;
1125 fDisplacement.set(r*std::cos(Phi),r*std::sin(Phi),0.0);
1126 }
1127}
1128
1129//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
1130
1131void G4UrbanMscModel::SampleDisplacementNew(G4double, G4double phi)
1132{
1133 // best sampling based on single scattering results
1134 G4double rmax = sqrt((tPathLength-zPathLength)*(tPathLength+zPathLength));
1135 G4double r(0.0);
1136 G4double u(0.0);
1137 static const G4double reps = 5.e-3;
1138
1139 if(rmax > 0.)
1140 {
1141 static const G4double umax = 0.855;
1142 static const G4double wlow = 0.750;
1143
1144 static const G4double ralpha = 6.83e+0;
1145 static const G4double ra1 =-4.16179e+1;
1146 static const G4double ra2 = 1.12548e+2;
1147 static const G4double ra3 =-8.66665e+1;
1148 static const G4double ralpha1 = 0.751*ralpha;
1149 static const G4double ralpha2 =ralpha-ralpha1;
1150 static const G4double rwa1 = G4Exp(ralpha1*reps);
1151 static const G4double rwa2 = G4Exp(ralpha1*umax)-rwa1;
1152 static const G4double rejamax = 1.16456;
1153
1154 static const G4double rbeta = 2.18e+1;
1155 static const G4double rb0 = 4.81382e+2;
1156 static const G4double rb1 =-1.12842e+4;
1157 static const G4double rb2 = 4.57745e+4;
1158 static const G4double rbeta1 = 0.732*rbeta;
1159 static const G4double rbeta2 = rbeta-rbeta1;
1160 static const G4double rwb1 = G4Exp(-rbeta1*umax);
1161 static const G4double rwb2 = rwb1-G4Exp(-rbeta1*(1.-reps));
1162 static const G4double rejbmax = 1.62651;
1163
1164 G4int count = 0;
1165 G4double uc,rej;
1166
1167 if(rndmEngineMod->flat() < wlow)
1168 {
1169 do {
1170 u = G4Log(rwa1+rwa2*rndmEngineMod->flat())/ralpha1;
1171 uc = umax-u;
1172 rej = G4Exp(-ralpha2*uc)*
1173 (1.+ralpha*uc+ra1*uc*uc+ra2*uc*uc*uc+ra3*uc*uc*uc*uc);
1174 } while (rejamax*rndmEngineMod->flat() > rej && ++count < 1000);
1175 }
1176 else
1177 {
1178 do {
1179 u = -G4Log(rwb1-rwb2*rndmEngineMod->flat())/rbeta1;
1180 uc = u-umax;
1181 rej = G4Exp(-rbeta2*uc)*
1182 (1.+rbeta*uc+rb0*uc*uc+rb1*uc*uc*uc+rb2*uc*uc*uc*uc);
1183 } while (rejbmax*rndmEngineMod->flat() > rej && ++count < 1000);
1184 }
1185 r = rmax*u;
1186 }
1187
1188 if(r > 0.)
1189 {
1190 // sample Phi using lateral correlation
1191 // and r/rmax - (Phi-phi) correlation
1192 // v = Phi-phi = acos(latcorr/(r*sth))
1193 // from SS simulation f(v)*g(v)
1194 // f(v) ~ exp(-a1*v) normalized distribution
1195 // g(v) rejection function (0 < g(v) <= 1)
1196 G4double v, rej;
1197
1198 static const G4double peps = 1.e-4;
1199 static const G4double Pi = CLHEP::pi;
1200 static const G4double palpha[10] = {2.300e+0,2.490e+0,2.610e+0,2.820e+0,2.710e+0,
1201 2.750e+0,2.910e+0,3.400e+0,4.150e+0,5.400e+0};
1202 static const G4double palpha1[10]= {4.600e-2,1.245e-1,2.610e-1,2.820e-1,2.710e-1,
1203 6.875e-1,1.019e+0,1.360e+0,1.660e+0,2.430e+0};
1204 static const G4double pejmax[10] = {3.513,1.968,1.479,1.239,1.116,
1205 1.081,1.064,1.073,1.103,1.158};
1206
1207 static const G4double pa1[10] = { 3.218e+0, 2.412e+0, 2.715e+0, 2.787e+0, 2.541e+0,
1208 2.508e+0, 2.600e+0, 3.231e+0, 4.588e+0, 6.584e+0};
1209 static const G4double pa2[10] = {-5.528e-1, 2.523e+0, 1.738e+0, 2.082e+0, 1.423e+0,
1210 4.682e-1,-6.883e-1,-2.147e+0,-5.127e+0,-1.054e+1};
1211 static const G4double pa3[10] = { 3.618e+0, 2.032e+0, 2.341e+0, 2.172e+0, 7.205e-1,
1212 4.655e-1, 6.318e-1, 1.255e+0, 2.425e+0, 4.938e+0};
1213 static const G4double pa4[10] = { 2.437e+0, 9.450e-1, 4.349e-1, 2.221e-1, 1.130e-1,
1214 5.405e-2, 2.245e-2, 7.370e-3, 1.456e-3, 1.508e-4};
1215 static const G4double pw1[10] = {G4Exp(-palpha1[0]*peps),G4Exp(-palpha1[1]*peps),
1216 G4Exp(-palpha1[2]*peps),G4Exp(-palpha1[3]*peps),
1217 G4Exp(-palpha1[4]*peps),G4Exp(-palpha1[5]*peps),
1218 G4Exp(-palpha1[6]*peps),G4Exp(-palpha1[7]*peps),
1219 G4Exp(-palpha1[8]*peps),G4Exp(-palpha1[9]*peps)};
1220 static const G4double pw2[10] = {pw1[0]-G4Exp(-palpha1[0]*(Pi-peps)),
1221 pw1[1]-G4Exp(-palpha1[1]*(Pi-peps)),
1222 pw1[2]-G4Exp(-palpha1[2]*(Pi-peps)),
1223 pw1[3]-G4Exp(-palpha1[3]*(Pi-peps)),
1224 pw1[4]-G4Exp(-palpha1[4]*(Pi-peps)),
1225 pw1[5]-G4Exp(-palpha1[5]*(Pi-peps)),
1226 pw1[6]-G4Exp(-palpha1[6]*(Pi-peps)),
1227 pw1[7]-G4Exp(-palpha1[7]*(Pi-peps)),
1228 pw1[8]-G4Exp(-palpha1[8]*(Pi-peps)),
1229 pw1[9]-G4Exp(-palpha1[9]*(Pi-peps))};
1230
1231 G4int iphi = u*10.;
1232 if(iphi < 0) { iphi = 0; }
1233 else if(iphi > 9) { iphi = 9; }
1234 G4int count = 0;
1235
1236 do {
1237 v = -G4Log(pw1[iphi]-pw2[iphi]*rndmEngineMod->flat())/palpha1[iphi];
1238 rej = (G4Exp(-palpha[iphi]*v)*
1239 (1+pa1[iphi]*v+pa2[iphi]*v*v+pa3[iphi]*v*v*v)+pa4[iphi])/
1240 G4Exp(-pw1[iphi]*v);
1241 }
1242 // Loop checking, 5-March-2018, Vladimir Ivanchenko
1243 while (pejmax[iphi]*rndmEngineMod->flat() > rej && ++count < 1000);
1244
1245 G4double Phi = (rndmEngineMod->flat() < 0.5) ? phi+v : phi-v;
1246 fDisplacement.set(r*std::cos(Phi),r*std::sin(Phi),0.0);
1247 }
1248}
1249
1250//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
1251
1252void G4UrbanMscModel::InitialiseModelCache()
1253{
1254 // it is assumed, that for the second run only addition
1255 // of a new G4MaterialCutsCouple is possible
1256 auto theCoupleTable = G4ProductionCutsTable::GetProductionCutsTable();
1257 size_t numOfCouples = theCoupleTable->GetTableSize();
1258 if(numOfCouples != msc.size()) { msc.resize(numOfCouples); }
1259
1260 for(size_t j=0; j<numOfCouples; ++j) {
1261 auto aCouple = theCoupleTable->GetMaterialCutsCouple(j);
1262
1263 // cut may be changed before runs
1264 G4double cut = aCouple->GetProductionCuts()->GetProductionCut(1);
1265 if(msc[j]) {
1266 msc[j]->ecut = cut;
1267 continue;
1268 }
1269 // new couple
1270 msc[j] = new mscData();
1271 msc[j]->ecut = cut;
1272 G4double Zeff = aCouple->GetMaterial()->GetIonisation()->GetZeffective();
1273 msc[j]->Zeff = Zeff;
1274 msc[j]->sqrtZ = std::sqrt(Zeff);
1275 G4double lnZ = G4Log(Zeff);
1276 // correction in theta0 formula
1277 G4double w = G4Exp(lnZ/6.);
1278 G4double facz = 0.990395+w*(-0.168386+w*0.093286) ;
1279 msc[j]->coeffth1 = facz*(1. - 8.7780e-2/Zeff);
1280 msc[j]->coeffth2 = facz*(4.0780e-2 + 1.7315e-4*Zeff);
1281
1282 // tail parameters
1283 G4double Z13 = w*w;
1284 msc[j]->coeffc1 = 2.3785 - Z13*(4.1981e-1 - Z13*6.3100e-2);
1285 msc[j]->coeffc2 = 4.7526e-1 + Z13*(1.7694 - Z13*3.3885e-1);
1286 msc[j]->coeffc3 = 2.3683e-1 - Z13*(1.8111 - Z13*3.2774e-1);
1287 msc[j]->coeffc4 = 1.7888e-2 + Z13*(1.9659e-2 - Z13*2.6664e-3);
1288
1289 msc[j]->Z23 = Z13*Z13;
1290
1291 msc[j]->stepmina = 27.725/(1.+0.203*Zeff);
1292 msc[j]->stepminb = 6.152/(1.+0.111*Zeff);
1293
1294 // 21.07.2020
1295 msc[j]->doverra = 9.6280e-1 - 8.4848e-2*msc[j]->sqrtZ + 4.3769e-3*Zeff;
1296
1297 // 06.10.2020
1298 // msc[j]->doverra = 7.7024e-1 - 6.7878e-2*msc[j]->sqrtZ + 3.5015e-3*Zeff;
1299
1300 msc[j]->doverrb = 1.15 - 9.76e-4*Zeff;
1301 }
1302}
1303
1304//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
G4Exp
G4double G4Exp(G4double initial_x)
Exponential Function double precision.
Definition: G4Exp.hh:179
G4Log
G4double G4Log(G4double x)
Definition: G4Log.hh:226
fUseSafety
@ fUseSafety
Definition: G4MscStepLimitType.hh:49
fUseSafetyPlus
@ fUseSafetyPlus
Definition: G4MscStepLimitType.hh:50
fUseDistanceToBoundary
@ fUseDistanceToBoundary
Definition: G4MscStepLimitType.hh:51
G4StepStatus
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Definition: G4StepStatus.hh:40
fGeomBoundary
@ fGeomBoundary
Definition: G4StepStatus.hh:43
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Definition: G4Types.hh:83
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Definition: G4Types.hh:86
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Definition: G4Types.hh:85
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Definition: ThreeVector.cc:33
CLHEP::HepRandomEngine::flat
virtual double flat()=0
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G4double GetLogKineticEnergy() const
G4DynamicParticle::GetDefinition
G4ParticleDefinition * GetDefinition() const
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Definition: G4EmParameters.cc:325
G4EmParameters::Instance
static G4EmParameters * Instance()
Definition: G4EmParameters.cc:67
G4LossTableManager::Instance
static G4LossTableManager * Instance()
Definition: G4LossTableManager.cc:87
G4MaterialCutsCouple::GetMaterial
const G4Material * GetMaterial() const
Definition: G4MaterialCutsCouple.hh:166
G4Material::GetRadlen
G4double GetRadlen() const
Definition: G4Material.hh:218
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void ProposeMomentumDirection(const G4ThreeVector &Pfinal)
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static G4Positron * Positron()
Definition: G4Positron.cc:93
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static G4Pow * GetInstance()
Definition: G4Pow.cc:41
G4Pow::Z23
G4double Z23(G4int Z) const
Definition: G4Pow.hh:125
G4ProductionCutsTable::GetProductionCutsTable
static G4ProductionCutsTable * GetProductionCutsTable()
Definition: G4ProductionCutsTable.cc:58
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G4StepPoint * GetPreStepPoint() const
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const G4DynamicParticle * GetDynamicParticle() const
G4Track::GetMaterialCutsCouple
const G4MaterialCutsCouple * GetMaterialCutsCouple() const
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const G4Step * GetStep() const
G4UrbanMscModel::SampleScattering
G4ThreeVector & SampleScattering(const G4ThreeVector &, G4double safety) override
Definition: G4UrbanMscModel.cc:821
G4UrbanMscModel::ComputeTrueStepLength
G4double ComputeTrueStepLength(G4double geomStepLength) override
Definition: G4UrbanMscModel.cc:776
G4UrbanMscModel::ComputeTheta0
G4double ComputeTheta0(G4double truePathLength, G4double KineticEnergy)
Definition: G4UrbanMscModel.cc:1056
G4UrbanMscModel::StartTracking
void StartTracking(G4Track *) override
Definition: G4UrbanMscModel.cc:423
G4UrbanMscModel::~G4UrbanMscModel
~G4UrbanMscModel() override
Definition: G4UrbanMscModel.cc:138
G4UrbanMscModel::G4UrbanMscModel
G4UrbanMscModel(const G4String &nam="UrbanMsc")
Definition: G4UrbanMscModel.cc:82
G4UrbanMscModel::Initialise
void Initialise(const G4ParticleDefinition *, const G4DataVector &) override
Definition: G4UrbanMscModel.cc:148
G4UrbanMscModel::ComputeGeomPathLength
G4double ComputeGeomPathLength(G4double truePathLength) override
Definition: G4UrbanMscModel.cc:715
G4UrbanMscModel::ComputeCrossSectionPerAtom
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Definition: G4UrbanMscModel.cc:170
G4UrbanMscModel::ComputeTruePathLengthLimit
G4double ComputeTruePathLengthLimit(const G4Track &track, G4double &currentMinimalStep) override
Definition: G4UrbanMscModel.cc:438
G4VEmModel::IsMaster
G4bool IsMaster() const
Definition: G4VEmModel.hh:736
G4VEmModel::SetCurrentCouple
void SetCurrentCouple(const G4MaterialCutsCouple *)
Definition: G4VEmModel.hh:465
G4VMscModel::dtrl
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Definition: G4VMscModel.hh:197
G4VMscModel::GetDEDX
G4double GetDEDX(const G4ParticleDefinition *part, G4double kineticEnergy, const G4MaterialCutsCouple *couple)
Definition: G4VMscModel.hh:300
G4VMscModel::facrange
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Definition: G4VMscModel.hh:193
G4VMscModel::ComputeGeomLimit
G4double ComputeGeomLimit(const G4Track &, G4double &presafety, G4double limit)
Definition: G4VMscModel.hh:287
G4VMscModel::skin
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Definition: G4VMscModel.hh:196
G4VMscModel::GetTransportMeanFreePath
G4double GetTransportMeanFreePath(const G4ParticleDefinition *part, G4double kinEnergy)
Definition: G4VMscModel.hh:405
G4VMscModel::GetParticleChangeForMSC
G4ParticleChangeForMSC * GetParticleChangeForMSC(const G4ParticleDefinition *p=nullptr)
Definition: G4VMscModel.cc:91
G4VMscModel::GetEnergy
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Definition: G4VMscModel.hh:368
G4VMscModel::GetRange
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Definition: G4VMscModel.hh:330
G4VMscModel::lambdalimit
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Definition: G4VMscModel.hh:198
G4VMscModel::steppingAlgorithm
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Definition: G4VMscModel.hh:203
G4VMscModel::ConvertTrueToGeom
G4double ConvertTrueToGeom(G4double &tLength, G4double &gLength)
Definition: G4VMscModel.hh:277
G4VMscModel::latDisplasment
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Definition: G4VMscModel.hh:206
G4VMscModel::ComputeSafety
G4double ComputeSafety(const G4ThreeVector &position, G4double limit=DBL_MAX)
Definition: G4VMscModel.hh:269
G4VMscModel::facsafety
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Definition: G4VMscModel.hh:195
G4VMscModel::fDisplacement
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Definition: G4VMscModel.hh:202
G4VMscModel::InitialiseParameters
void InitialiseParameters(const G4ParticleDefinition *)
Definition: G4VMscModel.cc:139
G4VMscModel::facgeom
G4double facgeom
Definition: G4VMscModel.hh:194
field_utils::Value1D::KineticEnergy
@ KineticEnergy
LOG_EKIN_MIN
#define LOG_EKIN_MIN
Definition: templates.hh:98
G4lrint
int G4lrint(double ad)
Definition: templates.hh:134