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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 sca
45 // H.W.Lewis Phys Rev 78 (1950) 526 and others
46
47 // -------------------------------------------
48 // In its present form the model can be used
49 // of the e-/e+ multiple scattering
50
51
52 //....oooOO0OOooo........oooOO0OOooo........oo
53 //....oooOO0OOooo........oooOO0OOooo........oo
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........oo
71
72 std::vector<G4UrbanMscModel::mscData*> G4Urban
73
74 namespace
75 {
76 G4Mutex theUrbanMutex = G4MUTEX_INITIALIZER;
77 }
78
79 //....oooOO0OOooo........oooOO0OOooo........oo
80
81 G4UrbanMscModel::G4UrbanMscModel(const G4Strin
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.;
103
104 positron = G4Positron::Positron();
105 rndmEngineMod = G4Random::getTheEngine();
106
107 drr = 0.35;
108 finalr = 10.*CLHEP::um;
109
110 tlow = 5.*CLHEP::keV;
111 invmev = 1.0/CLHEP::MeV;
112
113 skindepth = skin*stepmin;
114
115 mass = CLHEP::proton_mass_c2;
116 charge = chargeSquare = 1.0;
117 currentKinEnergy = currentRadLength = lambda
118 = zPathLength = par1 = par2 = par3 = rndma
119 currentLogKinEnergy = LOG_EKIN_MIN;
120 }
121
122 //....oooOO0OOooo........oooOO0OOooo........oo
123
124 G4UrbanMscModel::~G4UrbanMscModel()
125 {
126 if(isFirstInstance) {
127 for(auto const & ptr : msc) { delete ptr;
128 msc.clear();
129 }
130 }
131
132 //....oooOO0OOooo........oooOO0OOooo........oo
133
134 void G4UrbanMscModel::Initialise(const G4Parti
135 const G4DataV
136 {
137 // set values of some data members
138 SetParticle(p);
139 fParticleChange = GetParticleChangeForMSC(p)
140 InitialiseParameters(p);
141
142 latDisplasmentbackup = latDisplasment;
143
144 // if model is locked parameters should be d
145 if(!IsLocked()) {
146 dispAlg96 = G4EmParameters::Instance()->La
147 fPosiCorrection = G4EmParameters::Instance
148 }
149
150 // initialise cache only once
151 if(0 == msc.size()) {
152 G4AutoLock l(&theUrbanMutex);
153 if(0 == msc.size()) {
154 isFirstInstance = true;
155 msc.resize(1, nullptr);
156 }
157 l.unlock();
158 }
159 // initialise cache for each new run
160 if(isFirstInstance) { InitialiseModelCache()
161
162 /*
163 G4cout << "### G4UrbanMscModel::Initialise d
164 << p->GetParticleName() << " type= " << ste
165 G4cout << " RangeFact= " << facrange << "
166 << " SafetyFact= " << facsafety << " Lambda
167 << G4endl;
168 */
169 }
170
171 //....oooOO0OOooo........oooOO0OOooo........oo
172
173 G4double G4UrbanMscModel::ComputeCrossSectionP
174 const G4ParticleD
175 G4double ki
176 G4double at
177 G4double, G
178 {
179 static const G4double epsmin = 1.e-4 , epsma
180
181 static const G4double Zdat[15] = { 4., 6.,
182 50., 56.,
183
184 // corr. factors for e-/e+ lambda for T <= T
185 static const G4double celectron[15][22] =
186 {{1.125,1.072,1.051,1.047,1.047,1.05
187 1.054,1.057,1.062,1.069,1.075,1.09
188 1.112,1.108,1.100,1.093,1.089,1.08
189 {1.408,1.246,1.143,1.096,1.077,1.05
190 1.052,1.053,1.058,1.065,1.072,1.08
191 1.109,1.105,1.097,1.090,1.086,1.08
192 {2.833,2.268,1.861,1.612,1.486,1.30
193 1.136,1.114,1.106,1.106,1.109,1.11
194 1.131,1.124,1.113,1.104,1.099,1.09
195 {3.879,3.016,2.380,2.007,1.818,1.53
196 1.190,1.133,1.107,1.099,1.098,1.10
197 1.112,1.105,1.096,1.089,1.085,1.09
198 {6.937,4.330,2.886,2.256,1.987,1.62
199 1.203,1.122,1.080,1.065,1.061,1.06
200 1.073,1.070,1.064,1.059,1.056,1.05
201 {9.616,5.708,3.424,2.551,2.204,1.76
202 1.256,1.155,1.099,1.077,1.070,1.06
203 1.074,1.070,1.063,1.059,1.056,1.05
204 {11.72,6.364,3.811,2.806,2.401,1.88
205 1.300,1.180,1.112,1.082,1.073,1.06
206 1.068,1.064,1.059,1.054,1.051,1.05
207 {18.08,8.601,4.569,3.183,2.662,2.02
208 1.339,1.195,1.108,1.068,1.053,1.04
209 1.039,1.037,1.034,1.031,1.030,1.03
210 {18.22,10.48,5.333,3.713,3.115,2.36
211 1.498,1.301,1.171,1.105,1.077,1.04
212 1.031,1.028,1.024,1.022,1.021,1.02
213 {14.14,10.65,5.710,3.929,3.266,2.45
214 1.528,1.319,1.178,1.106,1.075,1.04
215 1.020,1.017,1.015,1.013,1.013,1.02
216 {14.11,11.73,6.312,4.240,3.478,2.56
217 1.569,1.342,1.186,1.102,1.065,1.02
218 0.995,0.993,0.993,0.993,0.993,1.01
219 {22.76,20.01,8.835,5.287,4.144,2.90
220 1.677,1.410,1.224,1.121,1.073,1.01
221 0.974,0.972,0.973,0.974,0.975,0.98
222 {50.77,40.85,14.13,7.184,5.284,3.43
223 1.837,1.512,1.283,1.153,1.091,1.01
224 0.950,0.947,0.949,0.952,0.954,0.96
225 {65.87,59.06,15.87,7.570,5.567,3.65
226 1.939,1.579,1.325,1.178,1.108,1.01
227 0.941,0.938,0.940,0.944,0.946,0.95
228 {55.60,47.34,15.92,7.810,5.755,3.76
229 1.985,1.609,1.343,1.188,1.113,1.01
230 0.933,0.930,0.933,0.936,0.939,0.94
231
232 static const G4double cpositron[15][22] = {
233 {2.589,2.044,1.658,1.446,1.347,1.21
234 1.097,1.083,1.080,1.086,1.092,1.10
235 1.131,1.126,1.117,1.108,1.103,1.10
236 {3.904,2.794,2.079,1.710,1.543,1.32
237 1.122,1.096,1.089,1.092,1.098,1.11
238 1.138,1.132,1.122,1.113,1.108,1.10
239 {7.970,6.080,4.442,3.398,2.872,2.12
240 1.357,1.246,1.194,1.179,1.178,1.18
241 1.203,1.190,1.173,1.159,1.151,1.14
242 {9.714,7.607,5.747,4.493,3.815,2.77
243 1.553,1.353,1.253,1.219,1.211,1.21
244 1.225,1.210,1.191,1.175,1.166,1.17
245 {17.97,12.95,8.628,6.065,4.849,3.22
246 1.624,1.382,1.259,1.214,1.202,1.20
247 1.217,1.203,1.184,1.169,1.160,1.15
248 {24.83,17.06,10.84,7.355,5.767,3.70
249 1.759,1.465,1.311,1.252,1.234,1.22
250 1.237,1.222,1.201,1.184,1.174,1.15
251 {23.26,17.15,11.52,8.049,6.375,4.11
252 1.880,1.535,1.353,1.281,1.258,1.24
253 1.252,1.234,1.212,1.194,1.183,1.17
254 {22.33,18.01,12.86,9.212,7.336,4.70
255 2.015,1.602,1.385,1.297,1.268,1.25
256 1.254,1.237,1.214,1.195,1.185,1.17
257 {33.91,24.13,15.71,10.80,8.507,5.46
258 2.407,1.873,1.564,1.425,1.374,1.33
259 1.312,1.288,1.258,1.235,1.221,1.20
260 {32.14,24.11,16.30,11.40,9.015,5.78
261 2.490,1.925,1.596,1.447,1.391,1.34
262 1.320,1.294,1.264,1.240,1.226,1.21
263 {29.51,24.07,17.19,12.28,9.766,6.23
264 2.602,1.995,1.641,1.477,1.414,1.35
265 1.328,1.302,1.270,1.245,1.231,1.23
266 {38.19,30.85,21.76,15.35,12.07,7.52
267 2.926,2.188,1.763,1.563,1.484,1.40
268 1.361,1.330,1.294,1.267,1.251,1.23
269 {49.71,39.80,27.96,19.63,15.36,9.40
270 3.417,2.478,1.944,1.692,1.589,1.48
271 1.409,1.372,1.330,1.298,1.280,1.25
272 {59.25,45.08,30.36,20.83,16.15,9.83
273 3.641,2.648,2.064,1.779,1.661,1.53
274 1.442,1.400,1.354,1.319,1.299,1.27
275 {56.38,44.29,30.50,21.18,16.51,10.1
276 3.752,2.724,2.116,1.817,1.692,1.55
277 1.456,1.412,1.364,1.328,1.307,1.28
278
279 //data/corrections for T > Tlim
280
281 static const G4double hecorr[15] = {
282 120.70, 117.50, 105.00, 92.92, 79.23, 74.
283 57.39, 41.97, 36.14, 24.53, 10.21, -7.8
284 -22.30};
285
286 G4double sigma;
287 SetParticle(part);
288
289 G4double Z23 = G4Pow::GetInstance()->Z23(G4l
290
291 // correction if particle .ne. e-/e+
292 // compute equivalent kinetic energy
293 // lambda depends on p*beta ....
294
295 G4double eKineticEnergy = kinEnergy;
296
297 if(mass > CLHEP::electron_mass_c2)
298 {
299 G4double TAU = kinEnergy/mass ;
300 G4double c = mass*TAU*(TAU+2.)/(CLHEP::el
301 G4double w = c-2.;
302 G4double tau = 0.5*(w+std::sqrt(w*w+4.*c)
303 eKineticEnergy = CLHEP::electron_mass_c2*
304 }
305
306 G4double eTotalEnergy = eKineticEnergy + CLH
307 G4double beta2 = eKineticEnergy*(eTotalEnerg
308 /(eTotalEnerg
309 G4double bg2 = eKineticEnergy*(eTotalEnerg
310 /(CLHEP::elec
311
312 static const G4double epsfactor = 2.*CLHEP::
313 CLHEP::electron_mass_c2*CLHEP::Bohr_radius
314 /(CLHEP::hbarc*CLHEP::hbarc);
315 G4double eps = epsfactor*bg2/Z23;
316
317 if (eps<epsmin) sigma = 2.*eps*eps;
318 else if(eps<epsmax) sigma = G4Log(1.+2.*eps
319 else sigma = G4Log(2.*eps)-1
320
321 sigma *= chargeSquare*atomicNumber*atomicNum
322
323 // interpolate in AtomicNumber and beta2
324 G4double c1,c2,cc1;
325
326 // get bin number in Z
327 G4int iZ = 14;
328 // Loop checking, 03-Aug-2015, Vladimir Ivan
329 while ((iZ>=0)&&(Zdat[iZ]>=atomicNumber)) {
330
331 iZ = std::min(std::max(iZ, 0), 13);
332
333 G4double ZZ1 = Zdat[iZ];
334 G4double ZZ2 = Zdat[iZ+1];
335 G4double ratZ = (atomicNumber-ZZ1)*(atomicNu
336 ((ZZ2-ZZ1)*(ZZ2+ZZ1));
337
338 static const G4double Tlim = 10.*CLHEP::MeV;
339 static const G4double sigmafactor =
340 CLHEP::twopi*CLHEP::classic_electr_radius*
341 static const G4double beta2lim = Tlim*(Tlim+
342 ((Tlim+CLHEP::electron_mass_c2)*(Tlim+CLHE
343 static const G4double bg2lim = Tlim*(Tlim+
344 (CLHEP::electron_mass_c2*CLHEP::electron_m
345
346 static const G4double sig0[15] = {
347 0.2672*CLHEP::barn, 0.5922*CLHEP::barn,
348 11.69*CLHEP::barn , 13.24*CLHEP::barn ,
349 35.13*CLHEP::barn , 39.95*CLHEP::barn ,
350 91.15*CLHEP::barn , 104.4*CLHEP::barn ,
351
352 static const G4double Tdat[22] = {
353 100*CLHEP::eV, 200*CLHEP::eV, 400*CLHEP:
354 1*CLHEP::keV, 2*CLHEP::keV, 4*CLHEP::k
355 10*CLHEP::keV, 20*CLHEP::keV, 40*CLHEP::
356 100*CLHEP::keV, 200*CLHEP::keV, 400*CLHEP:
357 1*CLHEP::MeV, 2*CLHEP::MeV, 4*CLHEP::M
358 10*CLHEP::MeV, 20*CLHEP::MeV};
359
360 if(eKineticEnergy <= Tlim)
361 {
362 // get bin number in T (beta2)
363 G4int iT = 21;
364 // Loop checking, 03-Aug-2015, Vladimir Iv
365 while ((iT>=0)&&(Tdat[iT]>=eKineticEnergy)
366
367 iT = std::min(std::max(iT, 0), 20);
368
369 // calculate betasquare values
370 G4double T = Tdat[iT];
371 G4double E = T + CLHEP::electron_mass_c2;
372 G4double b2small = T*(E+CLHEP::electron_ma
373
374 T = Tdat[iT+1];
375 E = T + CLHEP::electron_mass_c2;
376 G4double b2big = T*(E+CLHEP::electron_mass
377 G4double ratb2 = (beta2-b2small)/(b2big-b2
378
379 if (charge < 0.)
380 {
381 c1 = celectron[iZ][iT];
382 c2 = celectron[iZ+1][iT];
383 cc1 = c1+ratZ*(c2-c1);
384
385 c1 = celectron[iZ][iT+1];
386 c2 = celectron[iZ+1][iT+1];
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 }
397 G4double cc2 = c1+ratZ*(c2-c1);
398 sigma *= sigmafactor/(cc1+ratb2*(cc2-cc1))
399 }
400 else
401 {
402 c1 = bg2lim*sig0[iZ]*(1.+hecorr[iZ]*(beta2
403 c2 = bg2lim*sig0[iZ+1]*(1.+hecorr[iZ+1]*(b
404 if((atomicNumber >= ZZ1) && (atomicNumber
405 sigma = c1+ratZ*(c2-c1) ;
406 else if(atomicNumber < ZZ1)
407 sigma = atomicNumber*atomicNumber*c1/(ZZ
408 else if(atomicNumber > ZZ2)
409 sigma = atomicNumber*atomicNumber*c2/(ZZ
410 }
411 // low energy correction based on theory
412 sigma *= (1.+0.30/(1.+std::sqrt(1000.*eKinet
413
414 return sigma;
415 }
416
417 //....oooOO0OOooo........oooOO0OOooo........oo
418
419 void G4UrbanMscModel::StartTracking(G4Track* t
420 {
421 SetParticle(track->GetDynamicParticle()->Get
422 firstStep = true;
423 insideskin = false;
424 fr = facrange;
425 tlimit = tgeom = rangeinit = geombig;
426 smallstep = 1.e10;
427 stepmin = tlimitminfix;
428 tlimitmin = 10.*tlimitminfix;
429 rndmEngineMod = G4Random::getTheEngine();
430 }
431
432 //....oooOO0OOooo........oooOO0OOooo........oo
433
434 G4double G4UrbanMscModel::ComputeTruePathLengt
435 const G4Track& tr
436 G4double& current
437 {
438 tPathLength = currentMinimalStep;
439 const G4DynamicParticle* dp = track.GetDynam
440
441 G4StepPoint* sp = track.GetStep()->GetPreSte
442 G4StepStatus stepStatus = sp->GetStepStatus(
443 couple = track.GetMaterialCutsCouple();
444 SetCurrentCouple(couple);
445 idx = couple->GetIndex();
446 currentKinEnergy = dp->GetKineticEnergy();
447 currentLogKinEnergy = dp->GetLogKineticEnerg
448 currentRange = GetRange(particle,currentKinE
449 lambda0 = GetTransportMeanFreePath(particle,
450
451 tPathLength = std::min(tPathLength,currentRa
452 /*
453 G4cout << "G4Urban::StepLimit tPathLength= "
454 << " range= " <<currentRange<< " lambda= "<<
455 <<G4endl;
456 */
457 // extreme small step
458 if(tPathLength < tlimitminfix) {
459 latDisplasment = false;
460 return ConvertTrueToGeom(tPathLength, curr
461 }
462
463 presafety = (stepStatus == fGeomBoundary) ?
464 : ComputeSafety(sp->GetPosition(
465
466 // stop here if small step or range is less
467 if((tPathLength == currentRange && tPathLeng
468 tPathLength < tlimitminfix) {
469 latDisplasment = false;
470 return ConvertTrueToGeom(tPathLength, curr
471 }
472
473 // upper limit for the straight line distanc
474 // for electrons and positrons
475 G4double distance = (mass < masslimite)
476 ? currentRange*msc[idx]->doverra
477 // for muons, hadrons
478 : currentRange*msc[idx]->doverrb;
479
480 /*
481 G4cout << "G4Urban::StepLimit tPathLength= "
482 <<tPathLength<<" safety= " << pres
483 << " range= " <<currentRange<< " lam
484 << " Alg: " << steppingAlgorithm <
485 */
486 // far from geometry boundary
487 if(distance < presafety)
488 {
489 latDisplasment = false;
490 return ConvertTrueToGeom(tPathLength, cu
491 }
492
493 latDisplasment = latDisplasmentbackup;
494 // -----------------------------------------
495 // distance to boundary
496 if (steppingAlgorithm == fUseDistanceToBound
497 {
498 //compute geomlimit and presafety
499 geomlimit = ComputeGeomLimit(track, pres
500 /*
501 G4cout << "G4Urban::Distance to bounda
502 <<geomlimit<<" safety= " << presaf
503 */
504
505 smallstep += 1.;
506 insideskin = false;
507 tgeom = geombig;
508
509 // initialisation at first step and at t
510 if(firstStep || (stepStatus == fGeomBoun
511 {
512 rangeinit = currentRange;
513 if(!firstStep) { smallstep = 1.; }
514
515 //stepmin ~ lambda_elastic
516 stepmin = ComputeStepmin();
517 skindepth = skin*stepmin;
518 tlimitmin = ComputeTlimitmin();
519 /*
520 G4cout << "rangeinit= " << rangeinit
521 << " tlimitmin= " << tlimitmi
522 << geomlimit <<G4endl;
523 */
524 }
525 // constraint from the geometry
526 if((geomlimit < geombig) && (geomlimit >
527 {
528 // geomlimit is a geometrical step l
529 // transform it to true path length
530 if(lambda0 > geomlimit) {
531 geomlimit = -lambda0*G4Log(1.-geom
532 }
533 tgeom = (stepStatus == fGeomBoundary
534 : facrange*rangeinit + stepmin;
535 }
536
537 //step limit
538 tlimit = (currentRange > presafety) ?
539 std::max(facrange*rangeinit, facsafety
540
541 //lower limit for tlimit
542 tlimit = std::min(std::max(tlimit,tlimit
543 /*
544 G4cout << "tgeom= " << tgeom << " geomli
545 << " tlimit= " << tlimit << " pres
546 */
547 // shortcut
548 if((tPathLength < tlimit) && (tPathLengt
549 (smallstep > skin) && (tPathLength <
550 {
551 return ConvertTrueToGeom(tPathLength,
552 }
553
554 // step reduction near to boundary
555 if(smallstep <= skin)
556 {
557 tlimit = stepmin;
558 insideskin = true;
559 }
560 else if(geomlimit < geombig)
561 {
562 if(geomlimit > skindepth)
563 {
564 tlimit = std::min(tlimit, geomli
565 }
566 else
567 {
568 insideskin = true;
569 tlimit = std::min(tlimit, stepmi
570 }
571 }
572
573 tlimit = std::max(tlimit, stepmin);
574
575 // randomise if not 'small' step and ste
576 tPathLength = (tlimit < tPathLength && s
577 ? std::min(tPathLength, Randomizetlimi
578 : std::min(tPathLength, tlimit);
579 }
580 // -----------------------------------------
581 // for simulation with or without magnetic f
582 // there no small step/single scattering at
583 else if(steppingAlgorithm == fUseSafety)
584 {
585 if(firstStep || (stepStatus == fGeomBoun
586 rangeinit = currentRange;
587 fr = facrange;
588 // stepping for e+/e- only (not for mu
589 if(mass < masslimite)
590 {
591 rangeinit = std::max(rangeinit, la
592 if(lambda0 > lambdalimit) {
593 fr *= (0.75+0.25*lambda0/lambdal
594 }
595 }
596 //lower limit for tlimit
597 stepmin = ComputeStepmin();
598 tlimitmin = ComputeTlimitmin();
599 }
600
601 //step limit
602 tlimit = (currentRange > presafety) ?
603 std::max(fr*rangeinit, facsafety*presa
604
605 //lower limit for tlimit
606 tlimit = std::max(tlimit, tlimitmin);
607
608 // randomise if step determined by msc
609 tPathLength = (tlimit < tPathLength) ?
610 std::min(tPathLength, Randomizetlimit(
611 }
612 // -----------------------------------------
613 // for simulation with or without magnetic f
614 // there is small step/single scattering at
615 else if(steppingAlgorithm == fUseSafetyPlus)
616 {
617 if(firstStep || (stepStatus == fGeomBoun
618 rangeinit = currentRange;
619 fr = facrange;
620 if(mass < masslimite)
621 {
622 if(lambda0 > lambdalimit) {
623 fr *= (0.84+0.16*lambda0/lambdal
624 }
625 }
626 //lower limit for tlimit
627 stepmin = ComputeStepmin();
628 tlimitmin = ComputeTlimitmin();
629 }
630 //step limit
631 tlimit = (currentRange > presafety) ?
632 std::max(fr*rangeinit, facsafety*presafety)
633
634 //lower limit for tlimit
635 tlimit = std::max(tlimit, tlimitmin);
636
637 // condition for tPathLength from drr an
638 if(currentRange > finalr) {
639 G4double tmax = drr*currentRange+
640 finalr*(1.-drr)*(2.-fi
641 tPathLength = std::min(tPathLength,tma
642 }
643
644 // randomise if step determined by msc
645 tPathLength = (tlimit < tPathLength) ?
646 std::min(tPathLength, Randomizetlimit(
647 }
648
649 // -----------------------------------------
650 // simple step limitation
651 else
652 {
653 if (stepStatus == fGeomBoundary)
654 {
655 tlimit = (currentRange > lambda0)
656 ? facrange*currentRange : facrange*lambd
657 tlimit = std::max(tlimit, tlimitmin)
658 }
659 // randomise if step determined by msc
660 tPathLength = (tlimit < tPathLength) ?
661 std::min(tPathLength, Randomizetlimit(
662 }
663
664 // -----------------------------------------
665 firstStep = false;
666 return ConvertTrueToGeom(tPathLength, curren
667 }
668
669 //....oooOO0OOooo........oooOO0OOooo........oo
670
671 G4double G4UrbanMscModel::ComputeGeomPathLengt
672 {
673 lambdaeff = lambda0;
674 par1 = -1. ;
675 par2 = par3 = 0. ;
676
677 // this correction needed to run MSC with eI
678 // and makes no harm for a normal run
679 tPathLength = std::min(tPathLength,currentRa
680
681 // do the true -> geom transformation
682 zPathLength = tPathLength;
683
684 // z = t for very small tPathLength
685 if(tPathLength < tlimitminfix2) return zPath
686
687 /*
688 G4cout << "ComputeGeomPathLength: tpl= " <<
689 << " R= " << currentRange << " L0= "
690 << " E= " << currentKinEnergy << " "
691 << particle->GetParticleName() << G4e
692 */
693 G4double tau = tPathLength/lambda0 ;
694
695 if ((tau <= tausmall) || insideskin) {
696 zPathLength = std::min(tPathLength, lambda
697
698 } else if (tPathLength < currentRange*dtrl)
699 zPathLength = (tau < taulim) ? tPathLength
700 : lambda0*(1.-G4Exp(-tau));
701
702 } else if(currentKinEnergy < mass || tPathLe
703 par1 = 1./currentRange;
704 par2 = currentRange/lambda0;
705 par3 = 1.+par2;
706 if(tPathLength < currentRange) {
707 zPathLength =
708 (1.-G4Exp(par3*G4Log(1.-tPathLength/cu
709 } else {
710 zPathLength = 1./(par1*par3);
711 }
712
713 } else {
714 G4double rfin = std::max(currentRange-tPat
715 G4double T1 = GetEnergy(particle,rfin,coup
716 G4double lambda1 = GetTransportMeanFreePat
717
718 par1 = (lambda0-lambda1)/(lambda0*tPathLen
719 //G4cout << "par1= " << par1 << " L1= " <<
720 par2 = 1./(par1*lambda0);
721 par3 = 1.+par2;
722 zPathLength = (1.-G4Exp(par3*G4Log(lambda1
723 }
724
725 zPathLength = std::min(zPathLength, lambda0)
726 //G4cout<< "zPathLength= "<< zPathLength<< "
727 return zPathLength;
728 }
729
730 //....oooOO0OOooo........oooOO0OOooo........oo
731
732 G4double G4UrbanMscModel::ComputeTrueStepLengt
733 {
734 // step defined other than transportation
735 if(geomStepLength == zPathLength) {
736 //G4cout << "Urban::ComputeTrueLength: tPa
737 // << " step= " << geomStepLengt
738 return tPathLength;
739 }
740
741 zPathLength = geomStepLength;
742
743 // t = z for very small step
744 if(geomStepLength < tlimitminfix2) {
745 tPathLength = geomStepLength;
746
747 // recalculation
748 } else {
749
750 G4double tlength = geomStepLength;
751 if((geomStepLength > lambda0*tausmall) &&
752
753 if(par1 < 0.) {
754 tlength = -lambda0*G4Log(1.-geomStepLe
755 } else {
756 const G4double par4 = par1*par3;
757 if(par4*geomStepLength < 1.) {
758 tlength = (1.-G4Exp(G4Log(1.-par4*ge
759 } else {
760 tlength = currentRange;
761 }
762 }
763
764 if(tlength < geomStepLength) { tlength
765 else if(tlength > tPathLength) { tlength
766 }
767 tPathLength = tlength;
768 }
769 //G4cout << "Urban::ComputeTrueLength: tPath
770 // << " step= " << geomStepLength <<
771
772 return tPathLength;
773 }
774
775 //....oooOO0OOooo........oooOO0OOooo........oo
776
777 G4ThreeVector&
778 G4UrbanMscModel::SampleScattering(const G4Thre
779 G4double /*s
780 {
781 fDisplacement.set(0.0,0.0,0.0);
782 if(tPathLength >= currentRange) { return fDi
783
784 G4double kinEnergy = currentKinEnergy;
785 if (tPathLength > currentRange*dtrl) {
786 kinEnergy = GetEnergy(particle,currentRang
787 } else if(tPathLength > currentRange*0.01) {
788 kinEnergy -= tPathLength*GetDEDX(particle,
789 currentLo
790 }
791
792 if((tPathLength <= tlimitminfix) || (tPathLe
793 (kinEnergy <= CLHEP::eV)) { return fDispl
794
795 G4double cth = SampleCosineTheta(tPathLength
796
797 // protection against 'bad' cth values
798 if(std::abs(cth) >= 1.0) { return fDisplacem
799
800 G4double sth = std::sqrt((1.0 - cth)*(1.0 +
801 G4double phi = CLHEP::twopi*rndmEngineMod->f
802 G4ThreeVector newDirection(sth*std::cos(phi)
803 newDirection.rotateUz(oldDirection);
804
805 fParticleChange->ProposeMomentumDirection(ne
806 /*
807 G4cout << "G4UrbanMscModel::SampleSecondarie
808 << " sinTheta= " << sth << " safety(m
809 << " trueStep(mm)= " << tPathLength
810 << " geomStep(mm)= " << zPathLength
811 << G4endl;
812 */
813
814 if (latDisplasment && currentTau >= tausmall
815 if(dispAlg96) { SampleDisplacement(sth, ph
816 else { SampleDisplacementNew(cth,
817 fDisplacement.rotateUz(oldDirection);
818 }
819 return fDisplacement;
820 }
821
822 //....oooOO0OOooo........oooOO0OOooo........oo
823
824 G4double G4UrbanMscModel::SampleCosineTheta(G4
825 G4
826 {
827 G4double cth = 1.0;
828 G4double tau = trueStepLength/lambda0;
829
830 // mean tau value
831 if(currentKinEnergy != kinEnergy) {
832 G4double lambda1 = GetTransportMeanFreePat
833 if(std::abs(lambda1 - lambda0) > lambda0*0
834 tau = trueStepLength*G4Log(lambda0/lambd
835 }
836 }
837
838 currentTau = tau;
839 lambdaeff = trueStepLength/currentTau;
840 currentRadLength = couple->GetMaterial()->Ge
841
842 if (tau >= taubig) { cth = -1.+2.*rndmEngine
843 else if (tau >= tausmall) {
844 static const G4double numlim = 0.01;
845 static const G4double onethird = 1./3.;
846 if(tau < numlim) {
847 xmeanth = 1.0 - tau*(1.0 - 0.5*tau);
848 x2meanth= 1.0 - tau*(5.0 - 6.25*tau)*one
849 } else {
850 xmeanth = G4Exp(-tau);
851 x2meanth = (1.+2.*G4Exp(-2.5*tau))*oneth
852 }
853
854 // too large step of low-energy particle
855 G4double relloss = 1. - kinEnergy/currentK
856 static const G4double rellossmax= 0.50;
857 if(relloss > rellossmax) {
858 return SimpleScattering();
859 }
860 // is step extreme small ?
861 G4bool extremesmallstep = false;
862 G4double tsmall = std::min(tlimitmin,lambd
863
864 G4double theta0;
865 if(trueStepLength > tsmall) {
866 theta0 = ComputeTheta0(trueStepLength,ki
867 } else {
868 theta0 = std::sqrt(trueStepLength/tsmall
869 *ComputeTheta0(tsmall,kinEnergy);
870 extremesmallstep = true;
871 }
872
873 static const G4double onesixth = 1./6.;
874 static const G4double one12th = 1./12.;
875 static const G4double theta0max = CLHEP::p
876
877 // protection for very small angles
878 G4double theta2 = theta0*theta0;
879
880 if(theta2 < tausmall) { return cth; }
881 if(theta0 > theta0max) { return SimpleScat
882
883 G4double x = theta2*(1.0 - theta2*one12th)
884 if(theta2 > numlim) {
885 G4double sth = 2*std::sin(0.5*theta0);
886 x = sth*sth;
887 }
888
889 // parameter for tail
890 G4double ltau = G4Log(tau);
891 G4double u = !extremesmallstep ? G4Exp(lta
892 : G4Exp(G4Log(tsmall/lambda0)*onesixth);
893
894 G4double xx = G4Log(lambdaeff/currentRadL
895 G4double xsi = msc[idx]->coeffc1 +
896 u*(msc[idx]->coeffc2+msc[idx]->coeffc3*u
897
898 // tail should not be too big
899 xsi = std::max(xsi, 1.9);
900 /*
901 if(KineticEnergy > 20*MeV && xsi < 1.6)
902 G4cout << "G4UrbanMscModel::SampleCosi
903 << KineticEnergy/GeV
904 << " !!** c= " << xsi
905 << " **!! length(mm)= " << true
906 << " " << couple->GetMaterial()
907 << " tau= " << tau << G4endl;
908 }
909 */
910
911 G4double c = xsi;
912
913 if(std::abs(c-3.) < 0.001) { c = 3.00
914 else if(std::abs(c-2.) < 0.001) { c = 2.00
915
916 G4double c1 = c-1.;
917 G4double ea = G4Exp(-xsi);
918 G4double eaa = 1.-ea ;
919 G4double xmean1 = 1.-(1.-(1.+xsi)*ea)*x/ea
920 G4double x0 = 1. - xsi*x;
921
922 // G4cout << " xmean1= " << xmean1 << " x
923
924 if(xmean1 <= 0.999*xmeanth) { return Simpl
925
926 //from continuity of derivatives
927 G4double b = 1.+(c-xsi)*x;
928
929 G4double b1 = b+1.;
930 G4double bx = c*x;
931
932 G4double eb1 = G4Exp(G4Log(b1)*c1);
933 G4double ebx = G4Exp(G4Log(bx)*c1);
934 G4double d = ebx/eb1;
935
936 G4double xmean2 = (x0 + d - (bx - b1*d)/(c
937
938 G4double f1x0 = ea/eaa;
939 G4double f2x0 = c1/(c*(1. - d));
940 G4double prob = f2x0/(f1x0+f2x0);
941
942 G4double qprob = xmeanth/(prob*xmean1+(1.-
943
944 // sampling of costheta
945 //G4cout << "c= " << c << " qprob= " << qp
946 // << " c1= " << c1 << " b1= " << b1 << "
947 // << G4endl;
948 rndmEngineMod->flatArray(2, rndmarray);
949 if(rndmarray[0] < qprob)
950 {
951 G4double var = 0;
952 if(rndmarray[1] < prob) {
953 cth = 1.+G4Log(ea+rndmEngineMod->flat(
954 } else {
955 var = (1.0 - d)*rndmEngineMod->flat();
956 if(var < numlim*d) {
957 var /= (d*c1);
958 cth = -1.0 + var*(1.0 - 0.5*var*c)*(
959 } else {
960 cth = 1. + x*(c - xsi - c*G4Exp(-G4L
961 }
962 }
963 } else {
964 cth = -1.+2.*rndmarray[1];
965 }
966 }
967 return cth;
968 }
969
970 //....oooOO0OOooo........oooOO0OOooo........oo
971
972 G4double G4UrbanMscModel::ComputeTheta0(G4doub
973 G4doub
974 {
975 // for all particles take the width of the c
976 // from a parametrization similar to the H
977 // ( Highland formula: Particle Physics Book
978 G4double invbetacp = (kinEnergy+mass)/(kinEn
979 if(currentKinEnergy != kinEnergy) {
980 invbetacp = std::sqrt(invbetacp*(currentKi
981 (currentKinEnergy*(currentKinEnergy+2.
982 }
983 G4double y = trueStepLength/currentRadLength
984
985 if(fPosiCorrection && particle == positron)
986 {
987 static const G4double xl= 0.6;
988 static const G4double xh= 0.9;
989 static const G4double e = 113.0;
990 G4double corr;
991
992 G4double tau = std::sqrt(currentKinEnergy*
993 G4double x = std::sqrt(tau*(tau+2.)/((tau+
994 G4double a = msc[idx]->posa;
995 G4double b = msc[idx]->posb;
996 G4double c = msc[idx]->posc;
997 G4double d = msc[idx]->posd;
998 if(x < xl) {
999 corr = a*(1.-G4Exp(-b*x));
1000 } else if(x > xh) {
1001 corr = c+d*G4Exp(e*(x-1.));
1002 } else {
1003 G4double yl = a*(1.-G4Exp(-b*xl));
1004 G4double yh = c+d*G4Exp(e*(xh-1.));
1005 G4double y0 = (yh-yl)/(xh-xl);
1006 G4double y1 = yl-y0*xl;
1007 corr = y0*x+y1;
1008 }
1009 //=======================================
1010 y *= corr*msc[idx]->pose;
1011 }
1012
1013 static const G4double c_highland = 13.6*CLH
1014 G4double theta0 = c_highland*std::abs(charg
1015
1016 // correction factor from e- scattering dat
1017 theta0 *= (msc[idx]->coeffth1+msc[idx]->coe
1018 return theta0;
1019 }
1020
1021 //....oooOO0OOooo........oooOO0OOooo........o
1022
1023 void G4UrbanMscModel::SampleDisplacement(G4do
1024 {
1025 // simple and fast sampling
1026 // based on single scattering results
1027 // u = r/rmax : mean value
1028
1029 G4double rmax = std::sqrt((tPathLength-zPat
1030 if(rmax > 0.)
1031 {
1032 G4double r = 0.73*rmax;
1033
1034 // simple distribution for v=Phi-phi=psi
1035 // beta determined from the requirement t
1036 // the same mean value than that obtained
1037
1038 static const G4double cbeta = 2.160;
1039 static const G4double cbeta1 = 1. - G4Exp
1040 rndmEngineMod->flatArray(2, rndmarray);
1041 G4double psi = -G4Log(1. - rndmarray[0]*c
1042 G4double Phi = (rndmarray[1] < 0.5) ? phi
1043 fDisplacement.set(r*std::cos(Phi),r*std::
1044 }
1045 }
1046
1047 //....oooOO0OOooo........oooOO0OOooo........o
1048
1049 void G4UrbanMscModel::SampleDisplacementNew(G
1050 {
1051 // simple and fast sampling
1052 // based on single scattering results
1053 // u = (r/rmax)**2 : distribution from ss s
1054 const G4double eps = 1.e-3;
1055 const G4double rmax =
1056 std::sqrt((tPathLength-zPathLength)*(tPat
1057
1058 if(rmax > 0.)
1059 {
1060 const G4double x0 = 0.73 ;
1061 const G4double alpha = G4Log(7.33)/x0 ;
1062 const G4double a1 = 1.-x0 ;
1063 const G4double a2 = 1.-G4Exp(-alpha*x0) ;
1064 const G4double a3 = G4Exp(alpha*x0)-1. ;
1065 const G4double w1 = 2.*a2/(alpha*a1+2.*a2
1066
1067 G4double r, sqx;
1068 if (rmax/currentRange < eps)
1069 {
1070 r = 0.73*rmax ;
1071 sqx = 1.;
1072 }
1073 else
1074 {
1075 rndmEngineMod->flatArray(2,rndmarray);
1076 const G4double x = (rndmarray[0] < w1)
1077 1. - a1*std::sqrt(1.-rndmarray[1]);
1078
1079 sqx = std::sqrt(x);
1080 r = sqx*rmax;
1081 }
1082 // Gaussian distribution for Phi-phi=psi
1083 const G4double sigma = 0.1+0.9*sqx;
1084 const G4double psi = G4RandGauss::shoot(0
1085 const G4double Phi = phi+psi;
1086 fDisplacement.set(r*std::cos(Phi), r*std:
1087 }
1088 }
1089
1090 //....oooOO0OOooo........oooOO0OOooo........o
1091
1092 void G4UrbanMscModel::InitialiseModelCache()
1093 {
1094 // it is assumed, that for the second run o
1095 // of a new G4MaterialCutsCouple is possibl
1096 auto theCoupleTable = G4ProductionCutsTable
1097 std::size_t numOfCouples = theCoupleTable->
1098 if(numOfCouples != msc.size()) { msc.resize
1099
1100 for(G4int j=0; j<(G4int)numOfCouples; ++j)
1101 auto aCouple = theCoupleTable->GetMateria
1102
1103 // new couple
1104 msc[j] = new mscData();
1105 G4double Zeff = aCouple->GetMaterial()->G
1106 G4double sqrz = std::sqrt(Zeff);
1107 msc[j]->sqrtZ = sqrz;
1108 // parameterisation of step limitation
1109 msc[j]->factmin = dispAlg96 ? 0.001 : 0.0
1110 G4double lnZ = G4Log(Zeff);
1111 // correction in theta0 formula
1112 G4double w = G4Exp(lnZ/6.);
1113 G4double facz = 0.990395+w*(-0.168386+w*0
1114 msc[j]->coeffth1 = facz*(1. - 8.7780e-2/Z
1115 msc[j]->coeffth2 = facz*(4.0780e-2 + 1.73
1116
1117 // tail parameters
1118 G4double Z13 = w*w;
1119 msc[j]->coeffc1 = 2.3785 - Z13*(4.1981
1120 msc[j]->coeffc2 = 4.7526e-1 + Z13*(1.7694
1121 msc[j]->coeffc3 = 2.3683e-1 - Z13*(1.8111
1122 msc[j]->coeffc4 = 1.7888e-2 + Z13*(1.9659
1123
1124 msc[j]->Z23 = Z13*Z13;
1125
1126 msc[j]->stepmina = 27.725/(1.+0.203*Zeff)
1127 msc[j]->stepminb = 6.152/(1.+0.111*Zeff)
1128
1129 // 21.07.2020
1130 msc[j]->doverra = 9.6280e-1 - 8.4848e-2*m
1131
1132 // 06.10.2020
1133 // msc[j]->doverra = 7.7024e-1 - 6.7878e-
1134 msc[j]->doverrb = 1.15 - 9.76e-4*Zeff;
1135
1136 // corrections for e+
1137 msc[j]->posa = 0.994-4.08e-3*Zeff;
1138 msc[j]->posb = 7.16+(52.6+365./Zeff)/Zeff
1139 msc[j]->posc = 1.000-4.47e-3*Zeff;
1140 msc[j]->posd = 1.21e-3*Zeff;
1141 msc[j]->pose = 1.+Zeff*(1.84035e-4*Zeff-1
1142 }
1143 }
1144
1145 //....oooOO0OOooo........oooOO0OOooo........o
1146