Geant4 11.1.1
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// GEANT4 Class file
29//
30//
31// File name: G4UrbanMscModel
32//
33// Author: Laszlo Urban
34//
35// Creation date: 19.02.2013
36//
37// Created from G4UrbanMscModel96
38//
39// New parametrization for theta0
40// Correction for very small step length
41//
42// Class Description:
43//
44// Implementation of the model of multiple scattering based on
45// H.W.Lewis Phys Rev 78 (1950) 526 and others
46
47// -------------------------------------------------------------------
48// In its present form the model can be used for simulation
49// of the e-/e+ multiple scattering
50
51
52//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
53//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
54
55#include "G4UrbanMscModel.hh"
56#include "G4PhysicalConstants.hh"
57#include "G4SystemOfUnits.hh"
58#include "Randomize.hh"
59#include "G4Positron.hh"
60#include "G4EmParameters.hh"
61#include "G4ParticleChangeForMSC.hh"
62#include "G4ProductionCutsTable.hh"
63
64#include "G4Poisson.hh"
65#include "G4Pow.hh"
66#include "G4Log.hh"
67#include "G4Exp.hh"
68#include "G4AutoLock.hh"
69
70//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
71
72std::vector<G4UrbanMscModel::mscData*> G4UrbanMscModel::msc;
73
74namespace
75{
76 G4Mutex theUrbanMutex = G4MUTEX_INITIALIZER;
77}
78
79//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
80
81G4UrbanMscModel::G4UrbanMscModel(const G4String& nam)
82 : G4VMscModel(nam)
83{
84 masslimite = 0.6*CLHEP::MeV;
85 fr = 0.02;
86 taubig = 8.0;
87 tausmall = 1.e-16;
88 taulim = 1.e-6;
89 currentTau = taulim;
90 tlimitminfix = 0.01*CLHEP::nm;
91 tlimitminfix2 = 1.*CLHEP::nm;
92 stepmin = tlimitminfix;
93 smallstep = 1.e10;
94 currentRange = 0. ;
95 rangeinit = 0.;
96 tlimit = 1.e10*CLHEP::mm;
97 tlimitmin = 10.*tlimitminfix;
98 tgeom = 1.e50*CLHEP::mm;
99 geombig = tgeom;
100 geommin = 1.e-3*CLHEP::mm;
101 geomlimit = geombig;
102 presafety = 0.*CLHEP::mm;
103
104 particle = nullptr;
105
106 positron = G4Positron::Positron();
107 rndmEngineMod = G4Random::getTheEngine();
108
109 firstStep = true;
110 insideskin = false;
111 latDisplasmentbackup = false;
112 dispAlg96 = true;
113
114 drr = 0.35;
115 finalr = 10.*CLHEP::um;
116
117 tlow = 5.*CLHEP::keV;
118 invmev = 1.0/CLHEP::MeV;
119
120 skindepth = skin*stepmin;
121
122 mass = CLHEP::proton_mass_c2;
123 charge = chargeSquare = 1.0;
124 currentKinEnergy = currentRadLength = lambda0 = lambdaeff = tPathLength
125 = zPathLength = par1 = par2 = par3 = rndmarray[0] = rndmarray[1] = 0;
126 currentLogKinEnergy = LOG_EKIN_MIN;
127
128 idx = 0;
129 fParticleChange = nullptr;
130 couple = nullptr;
131}
132
133//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
134
135G4UrbanMscModel::~G4UrbanMscModel()
136{
137 if(isFirstInstance) {
138 for(auto & ptr : msc) { delete ptr; }
139 msc.clear();
140 }
141}
142
143//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
144
145void G4UrbanMscModel::Initialise(const G4ParticleDefinition* p,
146 const G4DataVector&)
147{
148 // set values of some data members
149 SetParticle(p);
150 fParticleChange = GetParticleChangeForMSC(p);
151 InitialiseParameters(p);
152
153 latDisplasmentbackup = latDisplasment;
154 dispAlg96 = G4EmParameters::Instance()->LateralDisplacementAlg96();
155 fPosiCorrection = G4EmParameters::Instance()->MscPositronCorrection();
156
157 // initialise cache only once
158 if(0 == msc.size()) {
159 G4AutoLock l(&theUrbanMutex);
160 if(0 == msc.size()) {
161 isFirstInstance = true;
162 msc.resize(1, nullptr);
163 }
164 l.unlock();
165 }
166 // initialise cache for each new run
167 if(isFirstInstance) { InitialiseModelCache(); }
168
169 /*
170 G4cout << "### G4UrbanMscModel::Initialise done for "
171 << p->GetParticleName() << " type= " << steppingAlgorithm << G4endl;
172 G4cout << " RangeFact= " << facrange << " GeomFact= " << facgeom
173 << " SafetyFact= " << facsafety << " LambdaLim= " << lambdalimit
174 << G4endl;
175 */
176}
177
178//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
179
180G4double G4UrbanMscModel::ComputeCrossSectionPerAtom(
181 const G4ParticleDefinition* part,
182 G4double kinEnergy,
183 G4double atomicNumber,G4double,
184 G4double, G4double)
185{
186 static const G4double epsmin = 1.e-4 , epsmax = 1.e10;
187
188 static const G4double Zdat[15] = { 4., 6., 13., 20., 26., 29., 32., 38.,47.,
189 50., 56., 64., 74., 79., 82. };
190
191 // corr. factors for e-/e+ lambda for T <= Tlim
192 static const G4double celectron[15][22] =
193 {{1.125,1.072,1.051,1.047,1.047,1.050,1.052,1.054,
194 1.054,1.057,1.062,1.069,1.075,1.090,1.105,1.111,
195 1.112,1.108,1.100,1.093,1.089,1.087 },
196 {1.408,1.246,1.143,1.096,1.077,1.059,1.053,1.051,
197 1.052,1.053,1.058,1.065,1.072,1.087,1.101,1.108,
198 1.109,1.105,1.097,1.090,1.086,1.082 },
199 {2.833,2.268,1.861,1.612,1.486,1.309,1.204,1.156,
200 1.136,1.114,1.106,1.106,1.109,1.119,1.129,1.132,
201 1.131,1.124,1.113,1.104,1.099,1.098 },
202 {3.879,3.016,2.380,2.007,1.818,1.535,1.340,1.236,
203 1.190,1.133,1.107,1.099,1.098,1.103,1.110,1.113,
204 1.112,1.105,1.096,1.089,1.085,1.098 },
205 {6.937,4.330,2.886,2.256,1.987,1.628,1.395,1.265,
206 1.203,1.122,1.080,1.065,1.061,1.063,1.070,1.073,
207 1.073,1.070,1.064,1.059,1.056,1.056 },
208 {9.616,5.708,3.424,2.551,2.204,1.762,1.485,1.330,
209 1.256,1.155,1.099,1.077,1.070,1.068,1.072,1.074,
210 1.074,1.070,1.063,1.059,1.056,1.052 },
211 {11.72,6.364,3.811,2.806,2.401,1.884,1.564,1.386,
212 1.300,1.180,1.112,1.082,1.073,1.066,1.068,1.069,
213 1.068,1.064,1.059,1.054,1.051,1.050 },
214 {18.08,8.601,4.569,3.183,2.662,2.025,1.646,1.439,
215 1.339,1.195,1.108,1.068,1.053,1.040,1.039,1.039,
216 1.039,1.037,1.034,1.031,1.030,1.036 },
217 {18.22,10.48,5.333,3.713,3.115,2.367,1.898,1.631,
218 1.498,1.301,1.171,1.105,1.077,1.048,1.036,1.033,
219 1.031,1.028,1.024,1.022,1.021,1.024 },
220 {14.14,10.65,5.710,3.929,3.266,2.453,1.951,1.669,
221 1.528,1.319,1.178,1.106,1.075,1.040,1.027,1.022,
222 1.020,1.017,1.015,1.013,1.013,1.020 },
223 {14.11,11.73,6.312,4.240,3.478,2.566,2.022,1.720,
224 1.569,1.342,1.186,1.102,1.065,1.022,1.003,0.997,
225 0.995,0.993,0.993,0.993,0.993,1.011 },
226 {22.76,20.01,8.835,5.287,4.144,2.901,2.219,1.855,
227 1.677,1.410,1.224,1.121,1.073,1.014,0.986,0.976,
228 0.974,0.972,0.973,0.974,0.975,0.987 },
229 {50.77,40.85,14.13,7.184,5.284,3.435,2.520,2.059,
230 1.837,1.512,1.283,1.153,1.091,1.010,0.969,0.954,
231 0.950,0.947,0.949,0.952,0.954,0.963 },
232 {65.87,59.06,15.87,7.570,5.567,3.650,2.682,2.182,
233 1.939,1.579,1.325,1.178,1.108,1.014,0.965,0.947,
234 0.941,0.938,0.940,0.944,0.946,0.954 },
235 {55.60,47.34,15.92,7.810,5.755,3.767,2.760,2.239,
236 1.985,1.609,1.343,1.188,1.113,1.013,0.960,0.939,
237 0.933,0.930,0.933,0.936,0.939,0.949 }};
238
239 static const G4double cpositron[15][22] = {
240 {2.589,2.044,1.658,1.446,1.347,1.217,1.144,1.110,
241 1.097,1.083,1.080,1.086,1.092,1.108,1.123,1.131,
242 1.131,1.126,1.117,1.108,1.103,1.100 },
243 {3.904,2.794,2.079,1.710,1.543,1.325,1.202,1.145,
244 1.122,1.096,1.089,1.092,1.098,1.114,1.130,1.137,
245 1.138,1.132,1.122,1.113,1.108,1.102 },
246 {7.970,6.080,4.442,3.398,2.872,2.127,1.672,1.451,
247 1.357,1.246,1.194,1.179,1.178,1.188,1.201,1.205,
248 1.203,1.190,1.173,1.159,1.151,1.145 },
249 {9.714,7.607,5.747,4.493,3.815,2.777,2.079,1.715,
250 1.553,1.353,1.253,1.219,1.211,1.214,1.225,1.228,
251 1.225,1.210,1.191,1.175,1.166,1.174 },
252 {17.97,12.95,8.628,6.065,4.849,3.222,2.275,1.820,
253 1.624,1.382,1.259,1.214,1.202,1.202,1.214,1.219,
254 1.217,1.203,1.184,1.169,1.160,1.151 },
255 {24.83,17.06,10.84,7.355,5.767,3.707,2.546,1.996,
256 1.759,1.465,1.311,1.252,1.234,1.228,1.238,1.241,
257 1.237,1.222,1.201,1.184,1.174,1.159 },
258 {23.26,17.15,11.52,8.049,6.375,4.114,2.792,2.155,
259 1.880,1.535,1.353,1.281,1.258,1.247,1.254,1.256,
260 1.252,1.234,1.212,1.194,1.183,1.170 },
261 {22.33,18.01,12.86,9.212,7.336,4.702,3.117,2.348,
262 2.015,1.602,1.385,1.297,1.268,1.251,1.256,1.258,
263 1.254,1.237,1.214,1.195,1.185,1.179 },
264 {33.91,24.13,15.71,10.80,8.507,5.467,3.692,2.808,
265 2.407,1.873,1.564,1.425,1.374,1.330,1.324,1.320,
266 1.312,1.288,1.258,1.235,1.221,1.205 },
267 {32.14,24.11,16.30,11.40,9.015,5.782,3.868,2.917,
268 2.490,1.925,1.596,1.447,1.391,1.342,1.332,1.327,
269 1.320,1.294,1.264,1.240,1.226,1.214 },
270 {29.51,24.07,17.19,12.28,9.766,6.238,4.112,3.066,
271 2.602,1.995,1.641,1.477,1.414,1.356,1.342,1.336,
272 1.328,1.302,1.270,1.245,1.231,1.233 },
273 {38.19,30.85,21.76,15.35,12.07,7.521,4.812,3.498,
274 2.926,2.188,1.763,1.563,1.484,1.405,1.382,1.371,
275 1.361,1.330,1.294,1.267,1.251,1.239 },
276 {49.71,39.80,27.96,19.63,15.36,9.407,5.863,4.155,
277 3.417,2.478,1.944,1.692,1.589,1.480,1.441,1.423,
278 1.409,1.372,1.330,1.298,1.280,1.258 },
279 {59.25,45.08,30.36,20.83,16.15,9.834,6.166,4.407,
280 3.641,2.648,2.064,1.779,1.661,1.531,1.482,1.459,
281 1.442,1.400,1.354,1.319,1.299,1.272 },
282 {56.38,44.29,30.50,21.18,16.51,10.11,6.354,4.542,
283 3.752,2.724,2.116,1.817,1.692,1.554,1.499,1.474,
284 1.456,1.412,1.364,1.328,1.307,1.282 }};
285
286 //data/corrections for T > Tlim
287
288 static const G4double hecorr[15] = {
289 120.70, 117.50, 105.00, 92.92, 79.23, 74.510, 68.29,
290 57.39, 41.97, 36.14, 24.53, 10.21, -7.855, -16.84,
291 -22.30};
292
293 G4double sigma;
294 SetParticle(part);
295
296 G4double Z23 = G4Pow::GetInstance()->Z23(G4lrint(atomicNumber));
297
298 // correction if particle .ne. e-/e+
299 // compute equivalent kinetic energy
300 // lambda depends on p*beta ....
301
302 G4double eKineticEnergy = kinEnergy;
303
304 if(mass > CLHEP::electron_mass_c2)
305 {
306 G4double TAU = kinEnergy/mass ;
307 G4double c = mass*TAU*(TAU+2.)/(CLHEP::electron_mass_c2*(TAU+1.)) ;
308 G4double w = c-2.;
309 G4double tau = 0.5*(w+std::sqrt(w*w+4.*c)) ;
310 eKineticEnergy = CLHEP::electron_mass_c2*tau ;
311 }
312
313 G4double eTotalEnergy = eKineticEnergy + CLHEP::electron_mass_c2 ;
314 G4double beta2 = eKineticEnergy*(eTotalEnergy+CLHEP::electron_mass_c2)
315 /(eTotalEnergy*eTotalEnergy);
316 G4double bg2 = eKineticEnergy*(eTotalEnergy+CLHEP::electron_mass_c2)
317 /(CLHEP::electron_mass_c2*CLHEP::electron_mass_c2);
318
319 static const G4double epsfactor = 2.*CLHEP::electron_mass_c2*
320 CLHEP::electron_mass_c2*CLHEP::Bohr_radius*CLHEP::Bohr_radius
321 /(CLHEP::hbarc*CLHEP::hbarc);
322 G4double eps = epsfactor*bg2/Z23;
323
324 if (eps<epsmin) sigma = 2.*eps*eps;
325 else if(eps<epsmax) sigma = G4Log(1.+2.*eps)-2.*eps/(1.+2.*eps);
326 else sigma = G4Log(2.*eps)-1.+1./eps;
327
328 sigma *= chargeSquare*atomicNumber*atomicNumber/(beta2*bg2);
329
330 // interpolate in AtomicNumber and beta2
331 G4double c1,c2,cc1;
332
333 // get bin number in Z
334 G4int iZ = 14;
335 // Loop checking, 03-Aug-2015, Vladimir Ivanchenko
336 while ((iZ>=0)&&(Zdat[iZ]>=atomicNumber)) { --iZ; }
337
338 iZ = std::min(std::max(iZ, 0), 13);
339
340 G4double ZZ1 = Zdat[iZ];
341 G4double ZZ2 = Zdat[iZ+1];
342 G4double ratZ = (atomicNumber-ZZ1)*(atomicNumber+ZZ1)/
343 ((ZZ2-ZZ1)*(ZZ2+ZZ1));
344
345 static const G4double Tlim = 10.*CLHEP::MeV;
346 static const G4double sigmafactor =
347 CLHEP::twopi*CLHEP::classic_electr_radius*CLHEP::classic_electr_radius;
348 static const G4double beta2lim = Tlim*(Tlim+2.*CLHEP::electron_mass_c2)/
349 ((Tlim+CLHEP::electron_mass_c2)*(Tlim+CLHEP::electron_mass_c2));
350 static const G4double bg2lim = Tlim*(Tlim+2.*CLHEP::electron_mass_c2)/
351 (CLHEP::electron_mass_c2*CLHEP::electron_mass_c2);
352
353 static const G4double sig0[15] = {
354 0.2672*CLHEP::barn, 0.5922*CLHEP::barn, 2.653*CLHEP::barn, 6.235*CLHEP::barn,
355 11.69*CLHEP::barn , 13.24*CLHEP::barn , 16.12*CLHEP::barn, 23.00*CLHEP::barn,
356 35.13*CLHEP::barn , 39.95*CLHEP::barn , 50.85*CLHEP::barn, 67.19*CLHEP::barn,
357 91.15*CLHEP::barn , 104.4*CLHEP::barn , 113.1*CLHEP::barn};
358
359 static const G4double Tdat[22] = {
360 100*CLHEP::eV, 200*CLHEP::eV, 400*CLHEP::eV, 700*CLHEP::eV,
361 1*CLHEP::keV, 2*CLHEP::keV, 4*CLHEP::keV, 7*CLHEP::keV,
362 10*CLHEP::keV, 20*CLHEP::keV, 40*CLHEP::keV, 70*CLHEP::keV,
363 100*CLHEP::keV, 200*CLHEP::keV, 400*CLHEP::keV, 700*CLHEP::keV,
364 1*CLHEP::MeV, 2*CLHEP::MeV, 4*CLHEP::MeV, 7*CLHEP::MeV,
365 10*CLHEP::MeV, 20*CLHEP::MeV};
366
367 if(eKineticEnergy <= Tlim)
368 {
369 // get bin number in T (beta2)
370 G4int iT = 21;
371 // Loop checking, 03-Aug-2015, Vladimir Ivanchenko
372 while ((iT>=0)&&(Tdat[iT]>=eKineticEnergy)) iT -= 1;
373
374 iT = std::min(std::max(iT, 0), 20);
375
376 // calculate betasquare values
377 G4double T = Tdat[iT];
378 G4double E = T + CLHEP::electron_mass_c2;
379 G4double b2small = T*(E+CLHEP::electron_mass_c2)/(E*E);
380
381 T = Tdat[iT+1];
382 E = T + CLHEP::electron_mass_c2;
383 G4double b2big = T*(E+CLHEP::electron_mass_c2)/(E*E);
384 G4double ratb2 = (beta2-b2small)/(b2big-b2small);
385
386 if (charge < 0.)
387 {
388 c1 = celectron[iZ][iT];
389 c2 = celectron[iZ+1][iT];
390 cc1 = c1+ratZ*(c2-c1);
391
392 c1 = celectron[iZ][iT+1];
393 c2 = celectron[iZ+1][iT+1];
394 }
395 else
396 {
397 c1 = cpositron[iZ][iT];
398 c2 = cpositron[iZ+1][iT];
399 cc1 = c1+ratZ*(c2-c1);
400
401 c1 = cpositron[iZ][iT+1];
402 c2 = cpositron[iZ+1][iT+1];
403 }
404 G4double cc2 = c1+ratZ*(c2-c1);
405 sigma *= sigmafactor/(cc1+ratb2*(cc2-cc1));
406 }
407 else
408 {
409 c1 = bg2lim*sig0[iZ]*(1.+hecorr[iZ]*(beta2-beta2lim))/bg2;
410 c2 = bg2lim*sig0[iZ+1]*(1.+hecorr[iZ+1]*(beta2-beta2lim))/bg2;
411 if((atomicNumber >= ZZ1) && (atomicNumber <= ZZ2))
412 sigma = c1+ratZ*(c2-c1) ;
413 else if(atomicNumber < ZZ1)
414 sigma = atomicNumber*atomicNumber*c1/(ZZ1*ZZ1);
415 else if(atomicNumber > ZZ2)
416 sigma = atomicNumber*atomicNumber*c2/(ZZ2*ZZ2);
417 }
418 // low energy correction based on theory
419 sigma *= (1.+0.30/(1.+std::sqrt(1000.*eKineticEnergy)));
420
421 return sigma;
422}
423
424//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
425
426void G4UrbanMscModel::StartTracking(G4Track* track)
427{
428 SetParticle(track->GetDynamicParticle()->GetDefinition());
429 firstStep = true;
430 insideskin = false;
431 fr = facrange;
432 tlimit = tgeom = rangeinit = geombig;
433 smallstep = 1.e10;
434 stepmin = tlimitminfix;
435 tlimitmin = 10.*tlimitminfix;
436 rndmEngineMod = G4Random::getTheEngine();
437}
438
439//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
440
441G4double G4UrbanMscModel::ComputeTruePathLengthLimit(
442 const G4Track& track,
443 G4double& currentMinimalStep)
444{
445 tPathLength = currentMinimalStep;
446 const G4DynamicParticle* dp = track.GetDynamicParticle();
447
448 G4StepPoint* sp = track.GetStep()->GetPreStepPoint();
449 G4StepStatus stepStatus = sp->GetStepStatus();
450 couple = track.GetMaterialCutsCouple();
451 SetCurrentCouple(couple);
452 idx = couple->GetIndex();
453 currentKinEnergy = dp->GetKineticEnergy();
454 currentLogKinEnergy = dp->GetLogKineticEnergy();
455 currentRange = GetRange(particle,currentKinEnergy,couple,currentLogKinEnergy);
456 lambda0 = GetTransportMeanFreePath(particle,currentKinEnergy,
457 currentLogKinEnergy);
458 tPathLength = std::min(tPathLength,currentRange);
459 /*
460 G4cout << "G4Urban::StepLimit tPathLength= " << tPathLength
461 << " range= " <<currentRange<< " lambda= "<<lambda0
462 <<G4endl;
463 */
464
465 // stop here if small step
466 if(tPathLength < tlimitminfix) {
467 latDisplasment = false;
468 return ConvertTrueToGeom(tPathLength, currentMinimalStep);
469 }
470
471 // upper limit for the straight line distance the particle can travel
472 // for electrons and positrons
473 G4double distance = (mass < masslimite)
474 ? currentRange*msc[idx]->doverra
475 // for muons, hadrons
476 : currentRange*msc[idx]->doverrb;
477
478 presafety = (stepStatus == fGeomBoundary) ? sp->GetSafety()
479 : ComputeSafety(sp->GetPosition(),tPathLength);
480 /*
481 G4cout << "G4Urban::StepLimit tPathLength= "
482 <<tPathLength<<" safety= " << presafety
483 << " range= " <<currentRange<< " lambda= "<<lambda0
484 << " Alg: " << steppingAlgorithm <<G4endl;
485 */
486 // far from geometry boundary
487 if(distance < presafety)
488 {
489 latDisplasment = false;
490 return ConvertTrueToGeom(tPathLength, currentMinimalStep);
491 }
492
493 latDisplasment = latDisplasmentbackup;
494 // ----------------------------------------------------------------
495 // distance to boundary
496 if (steppingAlgorithm == fUseDistanceToBoundary)
497 {
498 //compute geomlimit and presafety
499 geomlimit = ComputeGeomLimit(track, presafety, currentRange);
500 /*
501 G4cout << "G4Urban::Distance to boundary geomlimit= "
502 <<geomlimit<<" safety= " << presafety<<G4endl;
503 */
504
505 smallstep += 1.;
506 insideskin = false;
507
508 // initialisation at firs step and at the boundary
509 if(firstStep || (stepStatus == fGeomBoundary))
510 {
511 rangeinit = currentRange;
512 if(!firstStep) { smallstep = 1.; }
513
514 //stepmin ~ lambda_elastic
515 stepmin = ComputeStepmin();
516 skindepth = skin*stepmin;
517 tlimitmin = ComputeTlimitmin();
518 /*
519 G4cout << "rangeinit= " << rangeinit << " stepmin= " << stepmin
520 << " tlimitmin= " << tlimitmin << " geomlimit= "
521 << geomlimit <<G4endl;
522 */
523 // constraint from the geometry
524
525 if((geomlimit < geombig) && (geomlimit > geommin))
526 {
527 // geomlimit is a geometrical step length
528 // transform it to true path length (estimation)
529 if(lambda0 > geomlimit) {
530 geomlimit = -lambda0*G4Log(1.-geomlimit/lambda0)+tlimitmin;
531 }
532 tgeom = (stepStatus == fGeomBoundary)
533 ? geomlimit/facgeom : 2.*geomlimit/facgeom;
534 }
535 else
536 {
537 tgeom = geombig;
538 }
539 }
540
541 //step limit
542 tlimit = (currentRange > presafety) ?
543 std::max(facrange*rangeinit, facsafety*presafety) : currentRange;
544
545 //lower limit for tlimit
546 tlimit = std::min(std::max(tlimit,tlimitmin), tgeom);
547 /*
548 G4cout << "tgeom= " << tgeom << " geomlimit= " << geomlimit
549 << " tlimit= " << tlimit << " presafety= " << presafety << G4endl;
550 */
551 // shortcut
552 if((tPathLength < tlimit) && (tPathLength < presafety) &&
553 (smallstep > skin) && (tPathLength < geomlimit-0.999*skindepth))
554 {
555 return ConvertTrueToGeom(tPathLength, currentMinimalStep);
556 }
557
558 // step reduction near to boundary
559 if(smallstep <= skin)
560 {
561 tlimit = stepmin;
562 insideskin = true;
563 }
564 else if(geomlimit < geombig)
565 {
566 if(geomlimit > skindepth)
567 {
568 tlimit = std::min(tlimit, geomlimit-0.999*skindepth);
569 }
570 else
571 {
572 insideskin = true;
573 tlimit = std::min(tlimit, stepmin);
574 }
575 }
576
577 tlimit = std::max(tlimit, stepmin);
578
579 // randomise if not 'small' step and step determined by msc
580 tPathLength = (tlimit < tPathLength && smallstep > skin && !insideskin)
581 ? std::min(tPathLength, Randomizetlimit())
582 : std::min(tPathLength, tlimit);
583 }
584 // ----------------------------------------------------------------
585 // for simulation with or without magnetic field
586 // there no small step/single scattering at boundaries
587 else if(steppingAlgorithm == fUseSafety)
588 {
589 if(firstStep || (stepStatus == fGeomBoundary)) {
590 rangeinit = currentRange;
591 fr = facrange;
592 // stepping for e+/e- only (not for muons,hadrons)
593 if(mass < masslimite)
594 {
595 rangeinit = std::max(rangeinit, lambda0);
596 if(lambda0 > lambdalimit) {
597 fr *= (0.75+0.25*lambda0/lambdalimit);
598 }
599 }
600 //lower limit for tlimit
601 stepmin = ComputeStepmin();
602 tlimitmin = ComputeTlimitmin();
603 }
604
605 //step limit
606 tlimit = (currentRange > presafety) ?
607 std::max(fr*rangeinit, facsafety*presafety) : currentRange;
608
609 //lower limit for tlimit
610 tlimit = std::max(tlimit, tlimitmin);
611
612 // randomise if step determined by msc
613 tPathLength = (tlimit < tPathLength) ?
614 std::min(tPathLength, Randomizetlimit()) : tPathLength;
615 }
616 // ----------------------------------------------------------------
617 // for simulation with or without magnetic field
618 // there is small step/single scattering at boundaries
619 else if(steppingAlgorithm == fUseSafetyPlus)
620 {
621 if(firstStep || (stepStatus == fGeomBoundary)) {
622 rangeinit = currentRange;
623 fr = facrange;
624 if(mass < masslimite)
625 {
626 if(lambda0 > lambdalimit) {
627 fr *= (0.84+0.16*lambda0/lambdalimit);
628 }
629 }
630 //lower limit for tlimit
631 stepmin = ComputeStepmin();
632 tlimitmin = ComputeTlimitmin();
633 }
634 //step limit
635 tlimit = (currentRange > presafety) ?
636 std::max(fr*rangeinit, facsafety*presafety) : currentRange;
637
638 //lower limit for tlimit
639 tlimit = std::max(tlimit, tlimitmin);
640
641 // condition for tPathLength from drr and finalr
642 if(currentRange > finalr) {
643 G4double tmax = drr*currentRange+
644 finalr*(1.-drr)*(2.-finalr/currentRange);
645 tPathLength = std::min(tPathLength,tmax);
646 }
647
648 // randomise if step determined by msc
649 tPathLength = (tlimit < tPathLength) ?
650 std::min(tPathLength, Randomizetlimit()) : tPathLength;
651 }
652
653 // ----------------------------------------------------------------
654 // simple step limitation
655 else
656 {
657 if (stepStatus == fGeomBoundary)
658 {
659 tlimit = (currentRange > lambda0)
660 ? facrange*currentRange : facrange*lambda0;
661 tlimit = std::max(tlimit, tlimitmin);
662 }
663 // randomise if step determined by msc
664 tPathLength = (tlimit < tPathLength) ?
665 std::min(tPathLength, Randomizetlimit()) : tPathLength;
666 }
667
668 // ----------------------------------------------------------------
669 firstStep = false;
670 return ConvertTrueToGeom(tPathLength, currentMinimalStep);
671}
672
673//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
674
675G4double G4UrbanMscModel::ComputeGeomPathLength(G4double)
676{
677 lambdaeff = lambda0;
678 par1 = -1. ;
679 par2 = par3 = 0. ;
680
681 // this correction needed to run MSC with eIoni and eBrem inactivated
682 // and makes no harm for a normal run
683 tPathLength = std::min(tPathLength,currentRange);
684
685 // do the true -> geom transformation
686 zPathLength = tPathLength;
687
688 // z = t for very small tPathLength
689 if(tPathLength < tlimitminfix2) return zPathLength;
690
691 /*
692 G4cout << "ComputeGeomPathLength: tpl= " << tPathLength
693 << " R= " << currentRange << " L0= " << lambda0
694 << " E= " << currentKinEnergy << " "
695 << particle->GetParticleName() << G4endl;
696 */
697 G4double tau = tPathLength/lambda0 ;
698
699 if ((tau <= tausmall) || insideskin) {
700 zPathLength = std::min(tPathLength, lambda0);
701
702 } else if (tPathLength < currentRange*dtrl) {
703 zPathLength = (tau < taulim) ? tPathLength*(1.-0.5*tau)
704 : lambda0*(1.-G4Exp(-tau));
705
706 } else if(currentKinEnergy < mass || tPathLength == currentRange) {
707 par1 = 1./currentRange;
708 par2 = currentRange/lambda0;
709 par3 = 1.+par2;
710 if(tPathLength < currentRange) {
711 zPathLength =
712 (1.-G4Exp(par3*G4Log(1.-tPathLength/currentRange)))/(par1*par3);
713 } else {
714 zPathLength = 1./(par1*par3);
715 }
716
717 } else {
718 G4double rfin = std::max(currentRange-tPathLength, 0.01*currentRange);
719 G4double T1 = GetEnergy(particle,rfin,couple);
720 G4double lambda1 = GetTransportMeanFreePath(particle,T1);
721
722 par1 = (lambda0-lambda1)/(lambda0*tPathLength);
723 //G4cout << "par1= " << par1 << " L1= " << lambda1 << G4endl;
724 par2 = 1./(par1*lambda0);
725 par3 = 1.+par2;
726 zPathLength = (1.-G4Exp(par3*G4Log(lambda1/lambda0)))/(par1*par3);
727 }
728
729 zPathLength = std::min(zPathLength, lambda0);
730 //G4cout<< "zPathLength= "<< zPathLength<< " L0= " << lambda0 << G4endl;
731 return zPathLength;
732}
733
734//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
735
736G4double G4UrbanMscModel::ComputeTrueStepLength(G4double geomStepLength)
737{
738 // step defined other than transportation
739 if(geomStepLength == zPathLength) {
740 //G4cout << "Urban::ComputeTrueLength: tPathLength= " << tPathLength
741 // << " step= " << geomStepLength << " *** " << G4endl;
742 return tPathLength;
743 }
744
745 zPathLength = geomStepLength;
746
747 // t = z for very small step
748 if(geomStepLength < tlimitminfix2) {
749 tPathLength = geomStepLength;
750
751 // recalculation
752 } else {
753
754 G4double tlength = geomStepLength;
755 if((geomStepLength > lambda0*tausmall) && !insideskin) {
756
757 if(par1 < 0.) {
758 tlength = -lambda0*G4Log(1.-geomStepLength/lambda0) ;
759 } else {
760 const G4double par4 = par1*par3;
761 if(par4*geomStepLength < 1.) {
762 tlength = (1.-G4Exp(G4Log(1.-par4*geomStepLength)/par3))/par1;
763 } else {
764 tlength = currentRange;
765 }
766 }
767
768 if(tlength < geomStepLength) { tlength = geomStepLength; }
769 else if(tlength > tPathLength) { tlength = tPathLength; }
770 }
771 tPathLength = tlength;
772 }
773 //G4cout << "Urban::ComputeTrueLength: tPathLength= " << tPathLength
774 // << " step= " << geomStepLength << " &&& " << G4endl;
775
776 return tPathLength;
777}
778
779//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
780
781G4ThreeVector&
782G4UrbanMscModel::SampleScattering(const G4ThreeVector& oldDirection,
783 G4double /*safety*/)
784{
785 fDisplacement.set(0.0,0.0,0.0);
786 G4double kinEnergy = currentKinEnergy;
787 if (tPathLength > currentRange*dtrl) {
788 kinEnergy = GetEnergy(particle,currentRange-tPathLength,couple);
789 } else if(tPathLength > currentRange*0.01) {
790 kinEnergy -= tPathLength*GetDEDX(particle,currentKinEnergy,couple,
791 currentLogKinEnergy);
792 }
793
794 if((tPathLength <= tlimitminfix) || (tPathLength < tausmall*lambda0) ||
795 (kinEnergy <= CLHEP::eV)) { return fDisplacement; }
796
797 G4double cth = SampleCosineTheta(tPathLength,kinEnergy);
798
799 // protection against 'bad' cth values
800 if(std::abs(cth) >= 1.0) { return fDisplacement; }
801
802 G4double sth = std::sqrt((1.0 - cth)*(1.0 + cth));
803 G4double phi = CLHEP::twopi*rndmEngineMod->flat();
804 G4ThreeVector newDirection(sth*std::cos(phi),sth*std::sin(phi),cth);
805 newDirection.rotateUz(oldDirection);
806
807 fParticleChange->ProposeMomentumDirection(newDirection);
808 /*
809 G4cout << "G4UrbanMscModel::SampleSecondaries: e(MeV)= " << kineticEnergy
810 << " sinTheta= " << sth << " safety(mm)= " << safety
811 << " trueStep(mm)= " << tPathLength
812 << " geomStep(mm)= " << zPathLength
813 << G4endl;
814 */
815
816 if (latDisplasment && currentTau >= tausmall) {
817 if(dispAlg96) { SampleDisplacement(sth, phi); }
818 else { SampleDisplacementNew(cth, phi); }
819 fDisplacement.rotateUz(oldDirection);
820 }
821 return fDisplacement;
822}
823
824//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
825
826G4double G4UrbanMscModel::SampleCosineTheta(G4double trueStepLength,
827 G4double kinEnergy)
828{
829 G4double cth = 1.0;
830 G4double tau = trueStepLength/lambda0;
831
832 // mean tau value
833 if(currentKinEnergy != kinEnergy) {
834 G4double lambda1 = GetTransportMeanFreePath(particle, kinEnergy);
835 if(std::abs(lambda1 - lambda0) > lambda0*0.01 && lambda1 > 0.) {
836 tau = trueStepLength*G4Log(lambda0/lambda1)/(lambda0-lambda1);
837 }
838 }
839
840 currentTau = tau;
841 lambdaeff = trueStepLength/currentTau;
842 currentRadLength = couple->GetMaterial()->GetRadlen();
843
844 if (tau >= taubig) { cth = -1.+2.*rndmEngineMod->flat(); }
845 else if (tau >= tausmall) {
846 static const G4double numlim = 0.01;
847 static const G4double onethird = 1./3.;
848 if(tau < numlim) {
849 xmeanth = 1.0 - tau*(1.0 - 0.5*tau);
850 x2meanth= 1.0 - tau*(5.0 - 6.25*tau)*onethird;
851 } else {
852 xmeanth = G4Exp(-tau);
853 x2meanth = (1.+2.*G4Exp(-2.5*tau))*onethird;
854 }
855
856 // too large step of low-energy particle
857 G4double relloss = 1. - kinEnergy/currentKinEnergy;
858 static const G4double rellossmax= 0.50;
859 if(relloss > rellossmax) {
860 return SimpleScattering();
861 }
862 // is step extreme small ?
863 G4bool extremesmallstep = false;
864 G4double tsmall = std::min(tlimitmin,lambdalimit);
865
866 G4double theta0;
867 if(trueStepLength > tsmall) {
868 theta0 = ComputeTheta0(trueStepLength,kinEnergy);
869 } else {
870 theta0 = std::sqrt(trueStepLength/tsmall)
871 *ComputeTheta0(tsmall,kinEnergy);
872 extremesmallstep = true;
873 }
874
875 static const G4double onesixth = 1./6.;
876 static const G4double one12th = 1./12.;
877 static const G4double theta0max = CLHEP::pi*onesixth;
878
879 // protection for very small angles
880 G4double theta2 = theta0*theta0;
881
882 if(theta2 < tausmall) { return cth; }
883 if(theta0 > theta0max) { return SimpleScattering(); }
884
885 G4double x = theta2*(1.0 - theta2*one12th);
886 if(theta2 > numlim) {
887 G4double sth = 2*std::sin(0.5*theta0);
888 x = sth*sth;
889 }
890
891 // parameter for tail
892 G4double ltau = G4Log(tau);
893 G4double u = !extremesmallstep ? G4Exp(ltau*onesixth)
894 : G4Exp(G4Log(tsmall/lambda0)*onesixth);
895
896 G4double xx = G4Log(lambdaeff/currentRadLength);
897 G4double xsi = msc[idx]->coeffc1 +
898 u*(msc[idx]->coeffc2+msc[idx]->coeffc3*u)+msc[idx]->coeffc4*xx;
899
900 // tail should not be too big
901 xsi = std::max(xsi, 1.9);
902 /*
903 if(KineticEnergy > 20*MeV && xsi < 1.6) {
904 G4cout << "G4UrbanMscModel::SampleCosineTheta: E(GeV)= "
905 << KineticEnergy/GeV
906 << " !!** c= " << xsi
907 << " **!! length(mm)= " << trueStepLength << " Zeff= " << Zeff
908 << " " << couple->GetMaterial()->GetName()
909 << " tau= " << tau << G4endl;
910 }
911 */
912
913 G4double c = xsi;
914
915 if(std::abs(c-3.) < 0.001) { c = 3.001; }
916 else if(std::abs(c-2.) < 0.001) { c = 2.001; }
917
918 G4double c1 = c-1.;
919 G4double ea = G4Exp(-xsi);
920 G4double eaa = 1.-ea ;
921 G4double xmean1 = 1.-(1.-(1.+xsi)*ea)*x/eaa;
922 G4double x0 = 1. - xsi*x;
923
924 // G4cout << " xmean1= " << xmean1 << " xmeanth= " << xmeanth << G4endl;
925
926 if(xmean1 <= 0.999*xmeanth) { return SimpleScattering(); }
927
928 //from continuity of derivatives
929 G4double b = 1.+(c-xsi)*x;
930
931 G4double b1 = b+1.;
932 G4double bx = c*x;
933
934 G4double eb1 = G4Exp(G4Log(b1)*c1);
935 G4double ebx = G4Exp(G4Log(bx)*c1);
936 G4double d = ebx/eb1;
937
938 G4double xmean2 = (x0 + d - (bx - b1*d)/(c-2.))/(1. - d);
939
940 G4double f1x0 = ea/eaa;
941 G4double f2x0 = c1/(c*(1. - d));
942 G4double prob = f2x0/(f1x0+f2x0);
943
944 G4double qprob = xmeanth/(prob*xmean1+(1.-prob)*xmean2);
945
946 // sampling of costheta
947 //G4cout << "c= " << c << " qprob= " << qprob << " eb1= " << eb1
948 // << " c1= " << c1 << " b1= " << b1 << " bx= " << bx << " eb1= " << eb1
949 // << G4endl;
950 rndmEngineMod->flatArray(2, rndmarray);
951 if(rndmarray[0] < qprob)
952 {
953 G4double var = 0;
954 if(rndmarray[1] < prob) {
955 cth = 1.+G4Log(ea+rndmEngineMod->flat()*eaa)*x;
956 } else {
957 var = (1.0 - d)*rndmEngineMod->flat();
958 if(var < numlim*d) {
959 var /= (d*c1);
960 cth = -1.0 + var*(1.0 - 0.5*var*c)*(2. + (c - xsi)*x);
961 } else {
962 cth = 1. + x*(c - xsi - c*G4Exp(-G4Log(var + d)/c1));
963 }
964 }
965 } else {
966 cth = -1.+2.*rndmarray[1];
967 }
968 }
969 return cth;
970}
971
972//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
973
974G4double G4UrbanMscModel::ComputeTheta0(G4double trueStepLength,
975 G4double kinEnergy)
976{
977 // for all particles take the width of the central part
978 // from a parametrization similar to the Highland formula
979 // ( Highland formula: Particle Physics Booklet, July 2002, eq. 26.10)
980 G4double invbetacp = (kinEnergy+mass)/(kinEnergy*(kinEnergy+2.*mass));
981 if(currentKinEnergy != kinEnergy) {
982 invbetacp = std::sqrt(invbetacp*(currentKinEnergy+mass)/
983 (currentKinEnergy*(currentKinEnergy+2.*mass)));
984 }
985 G4double y = trueStepLength/currentRadLength;
986
987 if(fPosiCorrection && particle == positron)
988 {
989 static const G4double xl= 0.6;
990 static const G4double xh= 0.9;
991 static const G4double e = 113.0;
992 G4double corr;
993
994 G4double tau = std::sqrt(currentKinEnergy*kinEnergy)/mass;
995 G4double x = std::sqrt(tau*(tau+2.)/((tau+1.)*(tau+1.)));
996 G4double a = msc[idx]->posa;
997 G4double b = msc[idx]->posb;
998 G4double c = msc[idx]->posc;
999 G4double d = msc[idx]->posd;
1000 if(x < xl) {
1001 corr = a*(1.-G4Exp(-b*x));
1002 } else if(x > xh) {
1003 corr = c+d*G4Exp(e*(x-1.));
1004 } else {
1005 G4double yl = a*(1.-G4Exp(-b*xl));
1006 G4double yh = c+d*G4Exp(e*(xh-1.));
1007 G4double y0 = (yh-yl)/(xh-xl);
1008 G4double y1 = yl-y0*xl;
1009 corr = y0*x+y1;
1010 }
1011 //==================================================================
1012 y *= corr*msc[idx]->pose;
1013 }
1014
1015 static const G4double c_highland = 13.6*CLHEP::MeV;
1016 G4double theta0 = c_highland*std::abs(charge)*std::sqrt(y)*invbetacp;
1017
1018 // correction factor from e- scattering data
1019 theta0 *= (msc[idx]->coeffth1+msc[idx]->coeffth2*G4Log(y));
1020 return theta0;
1021}
1022
1023//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
1024
1025void G4UrbanMscModel::SampleDisplacement(G4double, G4double phi)
1026{
1027 // simple and fast sampling
1028 // based on single scattering results
1029 // u = r/rmax : mean value
1030
1031 G4double rmax = std::sqrt((tPathLength-zPathLength)*(tPathLength+zPathLength));
1032 if(rmax > 0.)
1033 {
1034 G4double r = 0.73*rmax;
1035
1036 // simple distribution for v=Phi-phi=psi ~exp(-beta*v)
1037 // beta determined from the requirement that distribution should give
1038 // the same mean value than that obtained from the ss simulation
1039
1040 static const G4double cbeta = 2.160;
1041 static const G4double cbeta1 = 1. - G4Exp(-cbeta*CLHEP::pi);
1042 rndmEngineMod->flatArray(2, rndmarray);
1043 G4double psi = -G4Log(1. - rndmarray[0]*cbeta1)/cbeta;
1044 G4double Phi = (rndmarray[1] < 0.5) ? phi+psi : phi-psi;
1045 fDisplacement.set(r*std::cos(Phi),r*std::sin(Phi),0.0);
1046 }
1047}
1048
1049//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
1050
1051void G4UrbanMscModel::SampleDisplacementNew(G4double, G4double phi)
1052{
1053 // best sampling based on single scattering results
1054 G4double rmax =
1055 std::sqrt((tPathLength-zPathLength)*(tPathLength+zPathLength));
1056 G4double r(0.0);
1057 G4double u(0.0);
1058 static const G4double reps = 5.e-3;
1059
1060 if(rmax > 0.)
1061 {
1062 static const G4double umax = 0.855;
1063 static const G4double wlow = 0.750;
1064
1065 static const G4double ralpha = 6.83e+0;
1066 static const G4double ra1 =-4.16179e+1;
1067 static const G4double ra2 = 1.12548e+2;
1068 static const G4double ra3 =-8.66665e+1;
1069 static const G4double ralpha1 = 0.751*ralpha;
1070 static const G4double ralpha2 =ralpha-ralpha1;
1071 static const G4double rwa1 = G4Exp(ralpha1*reps);
1072 static const G4double rwa2 = G4Exp(ralpha1*umax)-rwa1;
1073 static const G4double rejamax = 1.16456;
1074
1075 static const G4double rbeta = 2.18e+1;
1076 static const G4double rb0 = 4.81382e+2;
1077 static const G4double rb1 =-1.12842e+4;
1078 static const G4double rb2 = 4.57745e+4;
1079 static const G4double rbeta1 = 0.732*rbeta;
1080 static const G4double rbeta2 = rbeta-rbeta1;
1081 static const G4double rwb1 = G4Exp(-rbeta1*umax);
1082 static const G4double rwb2 = rwb1-G4Exp(-rbeta1*(1.-reps));
1083 static const G4double rejbmax = 1.62651;
1084
1085 G4int count = 0;
1086 G4double uc,rej;
1087
1088 if(rndmEngineMod->flat() < wlow)
1089 {
1090 do {
1091 rndmEngineMod->flatArray(2, rndmarray);
1092 u = G4Log(rwa1+rwa2*rndmarray[0])/ralpha1;
1093 uc = umax-u;
1094 rej = G4Exp(-ralpha2*uc)*
1095 (1.+ralpha*uc+ra1*uc*uc+ra2*uc*uc*uc+ra3*uc*uc*uc*uc);
1096 } while (rejamax*rndmarray[1] > rej && ++count < 1000);
1097 }
1098 else
1099 {
1100 do {
1101 rndmEngineMod->flatArray(2, rndmarray);
1102 u = -G4Log(rwb1-rwb2*rndmarray[0])/rbeta1;
1103 uc = u-umax;
1104 rej = G4Exp(-rbeta2*uc)*
1105 (1.+rbeta*uc+rb0*uc*uc+rb1*uc*uc*uc+rb2*uc*uc*uc*uc);
1106 } while (rejbmax*rndmarray[1] > rej && ++count < 1000);
1107 }
1108 r = rmax*u;
1109 }
1110
1111 if(r > 0.)
1112 {
1113 // sample Phi using lateral correlation
1114 // and r/rmax - (Phi-phi) correlation
1115 // v = Phi-phi = acos(latcorr/(r*sth))
1116 // from SS simulation f(v)*g(v)
1117 // f(v) ~ exp(-a1*v) normalized distribution
1118 // g(v) rejection function (0 < g(v) <= 1)
1119 G4double v, rej;
1120
1121 static const G4double peps = 1.e-4;
1122 static const G4double palpha[10] = {2.300e+0,2.490e+0,2.610e+0,2.820e+0,2.710e+0,
1123 2.750e+0,2.910e+0,3.400e+0,4.150e+0,5.400e+0};
1124 static const G4double palpha1[10]= {4.600e-2,1.245e-1,2.610e-1,2.820e-1,2.710e-1,
1125 6.875e-1,1.019e+0,1.360e+0,1.660e+0,2.430e+0};
1126 static const G4double pejmax[10] = {3.513,1.968,1.479,1.239,1.116,
1127 1.081,1.064,1.073,1.103,1.158};
1128
1129 static const G4double pa1[10] = { 3.218e+0, 2.412e+0, 2.715e+0, 2.787e+0, 2.541e+0,
1130 2.508e+0, 2.600e+0, 3.231e+0, 4.588e+0, 6.584e+0};
1131 static const G4double pa2[10] = {-5.528e-1, 2.523e+0, 1.738e+0, 2.082e+0, 1.423e+0,
1132 4.682e-1,-6.883e-1,-2.147e+0,-5.127e+0,-1.054e+1};
1133 static const G4double pa3[10] = { 3.618e+0, 2.032e+0, 2.341e+0, 2.172e+0, 7.205e-1,
1134 4.655e-1, 6.318e-1, 1.255e+0, 2.425e+0, 4.938e+0};
1135 static const G4double pa4[10] = { 2.437e+0, 9.450e-1, 4.349e-1, 2.221e-1, 1.130e-1,
1136 5.405e-2, 2.245e-2, 7.370e-3, 1.456e-3, 1.508e-4};
1137 static const G4double pw1[10] = {G4Exp(-palpha1[0]*peps),G4Exp(-palpha1[1]*peps),
1138 G4Exp(-palpha1[2]*peps),G4Exp(-palpha1[3]*peps),
1139 G4Exp(-palpha1[4]*peps),G4Exp(-palpha1[5]*peps),
1140 G4Exp(-palpha1[6]*peps),G4Exp(-palpha1[7]*peps),
1141 G4Exp(-palpha1[8]*peps),G4Exp(-palpha1[9]*peps)};
1142 static const G4double pw2[10] = {pw1[0]-G4Exp(-palpha1[0]*(CLHEP::pi-peps)),
1143 pw1[1]-G4Exp(-palpha1[1]*(CLHEP::pi-peps)),
1144 pw1[2]-G4Exp(-palpha1[2]*(CLHEP::pi-peps)),
1145 pw1[3]-G4Exp(-palpha1[3]*(CLHEP::pi-peps)),
1146 pw1[4]-G4Exp(-palpha1[4]*(CLHEP::pi-peps)),
1147 pw1[5]-G4Exp(-palpha1[5]*(CLHEP::pi-peps)),
1148 pw1[6]-G4Exp(-palpha1[6]*(CLHEP::pi-peps)),
1149 pw1[7]-G4Exp(-palpha1[7]*(CLHEP::pi-peps)),
1150 pw1[8]-G4Exp(-palpha1[8]*(CLHEP::pi-peps)),
1151 pw1[9]-G4Exp(-palpha1[9]*(CLHEP::pi-peps))};
1152
1153 G4int iphi = (G4int)(u*10.);
1154 if(iphi < 0) { iphi = 0; }
1155 else if(iphi > 9) { iphi = 9; }
1156 G4int count = 0;
1157
1158 do {
1159 rndmEngineMod->flatArray(2, rndmarray);
1160 v = -G4Log(pw1[iphi]-pw2[iphi]*rndmarray[0])/palpha1[iphi];
1161 rej = (G4Exp(-palpha[iphi]*v)*
1162 (1+pa1[iphi]*v+pa2[iphi]*v*v+pa3[iphi]*v*v*v)+pa4[iphi])/
1163 G4Exp(-pw1[iphi]*v);
1164 }
1165 // Loop checking, 5-March-2018, Vladimir Ivanchenko
1166 while (pejmax[iphi]*rndmarray[1] > rej && ++count < 1000);
1167
1168 G4double Phi = (rndmEngineMod->flat() < 0.5) ? phi+v : phi-v;
1169 fDisplacement.set(r*std::cos(Phi),r*std::sin(Phi),0.0);
1170 }
1171}
1172
1173//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
1174
1175void G4UrbanMscModel::InitialiseModelCache()
1176{
1177 // it is assumed, that for the second run only addition
1178 // of a new G4MaterialCutsCouple is possible
1179 auto theCoupleTable = G4ProductionCutsTable::GetProductionCutsTable();
1180 std::size_t numOfCouples = theCoupleTable->GetTableSize();
1181 if(numOfCouples != msc.size()) { msc.resize(numOfCouples, nullptr); }
1182
1183 for(G4int j=0; j<(G4int)numOfCouples; ++j) {
1184 auto aCouple = theCoupleTable->GetMaterialCutsCouple(j);
1185
1186 // new couple
1187 msc[j] = new mscData();
1188 G4double Zeff = aCouple->GetMaterial()->GetIonisation()->GetZeffective();
1189 msc[j]->sqrtZ = std::sqrt(Zeff);
1190 G4double lnZ = G4Log(Zeff);
1191 // correction in theta0 formula
1192 G4double w = G4Exp(lnZ/6.);
1193 G4double facz = 0.990395+w*(-0.168386+w*0.093286);
1194 msc[j]->coeffth1 = facz*(1. - 8.7780e-2/Zeff);
1195 msc[j]->coeffth2 = facz*(4.0780e-2 + 1.7315e-4*Zeff);
1196
1197 // tail parameters
1198 G4double Z13 = w*w;
1199 msc[j]->coeffc1 = 2.3785 - Z13*(4.1981e-1 - Z13*6.3100e-2);
1200 msc[j]->coeffc2 = 4.7526e-1 + Z13*(1.7694 - Z13*3.3885e-1);
1201 msc[j]->coeffc3 = 2.3683e-1 - Z13*(1.8111 - Z13*3.2774e-1);
1202 msc[j]->coeffc4 = 1.7888e-2 + Z13*(1.9659e-2 - Z13*2.6664e-3);
1203
1204 msc[j]->Z23 = Z13*Z13;
1205
1206 msc[j]->stepmina = 27.725/(1.+0.203*Zeff);
1207 msc[j]->stepminb = 6.152/(1.+0.111*Zeff);
1208
1209 // 21.07.2020
1210 msc[j]->doverra = 9.6280e-1 - 8.4848e-2*msc[j]->sqrtZ + 4.3769e-3*Zeff;
1211
1212 // 06.10.2020
1213 // msc[j]->doverra = 7.7024e-1 - 6.7878e-2*msc[j]->sqrtZ + 3.5015e-3*Zeff;
1214 msc[j]->doverrb = 1.15 - 9.76e-4*Zeff;
1215
1216 // corrections for e+
1217 msc[j]->posa = 0.994-4.08e-3*Zeff;
1218 msc[j]->posb = 7.16+(52.6+365./Zeff)/Zeff;
1219 msc[j]->posc = 1.000-4.47e-3*Zeff;
1220 msc[j]->posd = 1.21e-3*Zeff;
1221 msc[j]->pose = 1.+Zeff*(1.84035e-4*Zeff-1.86427e-2)+0.41125;
1222 }
1223}
1224
1225//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
G4Exp
G4double G4Exp(G4double initial_x)
Exponential Function double precision.
Definition: G4Exp.hh:180
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Definition: G4Log.hh:227
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@ fUseSafety
Definition: G4MscStepLimitType.hh:49
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@ fUseSafetyPlus
Definition: G4MscStepLimitType.hh:50
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Definition: G4MscStepLimitType.hh:51
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Definition: G4StepStatus.hh:40
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Definition: G4StepStatus.hh:43
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Definition: G4Threading.hh:85
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Definition: G4Threading.hh:81
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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
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virtual double flat()=0
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Definition: G4EmParameters.cc:334
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Definition: G4EmParameters.cc:70
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Definition: G4EmParameters.cc:517
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const G4Material * GetMaterial() const
Definition: G4MaterialCutsCouple.hh:166
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Definition: G4Material.hh:215
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Definition: G4ParticleChangeForMSC.hh:78
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Definition: G4Positron.cc:93
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static G4Pow * GetInstance()
Definition: G4Pow.cc:41
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Definition: G4Pow.hh:125
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Definition: G4ProductionCutsTable.cc:58
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const G4MaterialCutsCouple * GetMaterialCutsCouple() const
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Definition: G4UrbanMscModel.cc:782
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G4double ComputeTrueStepLength(G4double geomStepLength) override
Definition: G4UrbanMscModel.cc:736
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Definition: G4UrbanMscModel.cc:974
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void StartTracking(G4Track *) override
Definition: G4UrbanMscModel.cc:426
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~G4UrbanMscModel() override
Definition: G4UrbanMscModel.cc:135
G4UrbanMscModel::G4UrbanMscModel
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Definition: G4UrbanMscModel.cc:81
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void Initialise(const G4ParticleDefinition *, const G4DataVector &) override
Definition: G4UrbanMscModel.cc:145
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Definition: G4UrbanMscModel.cc:675
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Definition: G4UrbanMscModel.cc:180
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G4double ComputeTruePathLengthLimit(const G4Track &track, G4double &currentMinimalStep) override
Definition: G4UrbanMscModel.cc:441
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Definition: G4VEmModel.hh:468
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Definition: G4VMscModel.hh:203
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Definition: G4VMscModel.cc:158
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Definition: G4VMscModel.hh:199
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Definition: G4VMscModel.hh:296
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Definition: G4VMscModel.hh:202
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Definition: G4VMscModel.hh:325
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Definition: G4VMscModel.cc:77
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Definition: G4VMscModel.cc:223
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Definition: G4VMscModel.cc:188
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Definition: G4VMscModel.hh:204
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Definition: G4VMscModel.hh:209
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Definition: G4VMscModel.hh:212
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Definition: G4VMscModel.hh:278
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Definition: G4VMscModel.hh:201
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Definition: G4VMscModel.hh:208
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Definition: G4VMscModel.cc:115
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Definition: G4VMscModel.hh:200
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Definition: templates.hh:98
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Definition: templates.hh:134