source: trunk/source/processes/electromagnetic/standard/src/G4UrbanMscModel90.cc@ 1036

Last change on this file since 1036 was 1007, checked in by garnier, 17 years ago

update to geant4.9.2
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25//
26// $Id: G4UrbanMscModel90.cc,v 1.10 2008/10/29 14:15:30 vnivanch Exp $
27// GEANT4 tag $Name: geant4-09-02 $
28//
29// -------------------------------------------------------------------
30//
31// GEANT4 Class file
32//
33//
34// File name: G4UrbanMscModel90
35//
36// Author: V.Ivanchenko clone Laszlo Urban model
37//
38// Creation date: 07.12.2007
39//
40// Modifications:
41//
42//
43
44// Class Description:
45//
46// Implementation of the model of multiple scattering based on
47// H.W.Lewis Phys Rev 78 (1950) 526 and others
48
49// -------------------------------------------------------------------
50//
51
52
53//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
54//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
55
56#include "G4UrbanMscModel90.hh"
57#include "Randomize.hh"
58#include "G4Electron.hh"
59
60#include "G4LossTableManager.hh"
61#include "G4ParticleChangeForMSC.hh"
62#include "G4TransportationManager.hh"
63#include "G4SafetyHelper.hh"
64
65#include "G4Poisson.hh"
66
67//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
68
69using namespace std;
70
71G4UrbanMscModel90::G4UrbanMscModel90(const G4String& nam)
72 : G4VMscModel(nam),
73 isInitialized(false)
74{
75 taubig = 8.0;
76 tausmall = 1.e-20;
77 taulim = 1.e-6;
78 currentTau = taulim;
79 tlimitminfix = 1.e-6*mm;
80 stepmin = tlimitminfix;
81 smallstep = 1.e10;
82 currentRange = 0. ;
83 frscaling2 = 0.25;
84 frscaling1 = 1.-frscaling2;
85 tlimit = 1.e10*mm;
86 tlimitmin = 10.*tlimitminfix;
87 nstepmax = 25.;
88 geombig = 1.e50*mm;
89 geommin = 1.e-3*mm;
90 geomlimit = geombig;
91 presafety = 0.*mm;
92 Zeff = 1.;
93 particle = 0;
94 theManager = G4LossTableManager::Instance();
95 inside = false;
96 insideskin = false;
97}
98
99//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
100
101G4UrbanMscModel90::~G4UrbanMscModel90()
102{}
103
104//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
105
106void G4UrbanMscModel90::Initialise(const G4ParticleDefinition* p,
107 const G4DataVector&)
108{
109 skindepth = skin*stepmin;
110 if(isInitialized) return;
111
112 // set values of some data members
113 SetParticle(p);
114
115 if (pParticleChange) {
116 fParticleChange = reinterpret_cast<G4ParticleChangeForMSC*>(pParticleChange);
117 } else {
118 fParticleChange = new G4ParticleChangeForMSC();
119 }
120 safetyHelper = G4TransportationManager::GetTransportationManager()
121 ->GetSafetyHelper();
122 safetyHelper->InitialiseHelper();
123
124 isInitialized = true;
125}
126
127//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
128
129G4double G4UrbanMscModel90::ComputeCrossSectionPerAtom(
130 const G4ParticleDefinition* part,
131 G4double KineticEnergy,
132 G4double AtomicNumber,G4double,
133 G4double, G4double)
134{
135 const G4double sigmafactor = twopi*classic_electr_radius*classic_electr_radius;
136 const G4double epsfactor = 2.*electron_mass_c2*electron_mass_c2*
137 Bohr_radius*Bohr_radius/(hbarc*hbarc);
138 const G4double epsmin = 1.e-4 , epsmax = 1.e10;
139
140 const G4double Zdat[15] = { 4., 6., 13., 20., 26., 29., 32., 38., 47.,
141 50., 56., 64., 74., 79., 82. };
142
143 const G4double Tdat[22] = { 100*eV, 200*eV, 400*eV, 700*eV,
144 1*keV, 2*keV, 4*keV, 7*keV,
145 10*keV, 20*keV, 40*keV, 70*keV,
146 100*keV, 200*keV, 400*keV, 700*keV,
147 1*MeV, 2*MeV, 4*MeV, 7*MeV,
148 10*MeV, 20*MeV};
149
150 // corr. factors for e-/e+ lambda for T <= Tlim
151 G4double celectron[15][22] =
152 {{1.125,1.072,1.051,1.047,1.047,1.050,1.052,1.054,
153 1.054,1.057,1.062,1.069,1.075,1.090,1.105,1.111,
154 1.112,1.108,1.100,1.093,1.089,1.087 },
155 {1.408,1.246,1.143,1.096,1.077,1.059,1.053,1.051,
156 1.052,1.053,1.058,1.065,1.072,1.087,1.101,1.108,
157 1.109,1.105,1.097,1.090,1.086,1.082 },
158 {2.833,2.268,1.861,1.612,1.486,1.309,1.204,1.156,
159 1.136,1.114,1.106,1.106,1.109,1.119,1.129,1.132,
160 1.131,1.124,1.113,1.104,1.099,1.098 },
161 {3.879,3.016,2.380,2.007,1.818,1.535,1.340,1.236,
162 1.190,1.133,1.107,1.099,1.098,1.103,1.110,1.113,
163 1.112,1.105,1.096,1.089,1.085,1.098 },
164 {6.937,4.330,2.886,2.256,1.987,1.628,1.395,1.265,
165 1.203,1.122,1.080,1.065,1.061,1.063,1.070,1.073,
166 1.073,1.070,1.064,1.059,1.056,1.056 },
167 {9.616,5.708,3.424,2.551,2.204,1.762,1.485,1.330,
168 1.256,1.155,1.099,1.077,1.070,1.068,1.072,1.074,
169 1.074,1.070,1.063,1.059,1.056,1.052 },
170 {11.72,6.364,3.811,2.806,2.401,1.884,1.564,1.386,
171 1.300,1.180,1.112,1.082,1.073,1.066,1.068,1.069,
172 1.068,1.064,1.059,1.054,1.051,1.050 },
173 {18.08,8.601,4.569,3.183,2.662,2.025,1.646,1.439,
174 1.339,1.195,1.108,1.068,1.053,1.040,1.039,1.039,
175 1.039,1.037,1.034,1.031,1.030,1.036 },
176 {18.22,10.48,5.333,3.713,3.115,2.367,1.898,1.631,
177 1.498,1.301,1.171,1.105,1.077,1.048,1.036,1.033,
178 1.031,1.028,1.024,1.022,1.021,1.024 },
179 {14.14,10.65,5.710,3.929,3.266,2.453,1.951,1.669,
180 1.528,1.319,1.178,1.106,1.075,1.040,1.027,1.022,
181 1.020,1.017,1.015,1.013,1.013,1.020 },
182 {14.11,11.73,6.312,4.240,3.478,2.566,2.022,1.720,
183 1.569,1.342,1.186,1.102,1.065,1.022,1.003,0.997,
184 0.995,0.993,0.993,0.993,0.993,1.011 },
185 {22.76,20.01,8.835,5.287,4.144,2.901,2.219,1.855,
186 1.677,1.410,1.224,1.121,1.073,1.014,0.986,0.976,
187 0.974,0.972,0.973,0.974,0.975,0.987 },
188 {50.77,40.85,14.13,7.184,5.284,3.435,2.520,2.059,
189 1.837,1.512,1.283,1.153,1.091,1.010,0.969,0.954,
190 0.950,0.947,0.949,0.952,0.954,0.963 },
191 {65.87,59.06,15.87,7.570,5.567,3.650,2.682,2.182,
192 1.939,1.579,1.325,1.178,1.108,1.014,0.965,0.947,
193 0.941,0.938,0.940,0.944,0.946,0.954 },
194 {55.60,47.34,15.92,7.810,5.755,3.767,2.760,2.239,
195 1.985,1.609,1.343,1.188,1.113,1.013,0.960,0.939,
196 0.933,0.930,0.933,0.936,0.939,0.949 }};
197
198 G4double cpositron[15][22] = {
199 {2.589,2.044,1.658,1.446,1.347,1.217,1.144,1.110,
200 1.097,1.083,1.080,1.086,1.092,1.108,1.123,1.131,
201 1.131,1.126,1.117,1.108,1.103,1.100 },
202 {3.904,2.794,2.079,1.710,1.543,1.325,1.202,1.145,
203 1.122,1.096,1.089,1.092,1.098,1.114,1.130,1.137,
204 1.138,1.132,1.122,1.113,1.108,1.102 },
205 {7.970,6.080,4.442,3.398,2.872,2.127,1.672,1.451,
206 1.357,1.246,1.194,1.179,1.178,1.188,1.201,1.205,
207 1.203,1.190,1.173,1.159,1.151,1.145 },
208 {9.714,7.607,5.747,4.493,3.815,2.777,2.079,1.715,
209 1.553,1.353,1.253,1.219,1.211,1.214,1.225,1.228,
210 1.225,1.210,1.191,1.175,1.166,1.174 },
211 {17.97,12.95,8.628,6.065,4.849,3.222,2.275,1.820,
212 1.624,1.382,1.259,1.214,1.202,1.202,1.214,1.219,
213 1.217,1.203,1.184,1.169,1.160,1.151 },
214 {24.83,17.06,10.84,7.355,5.767,3.707,2.546,1.996,
215 1.759,1.465,1.311,1.252,1.234,1.228,1.238,1.241,
216 1.237,1.222,1.201,1.184,1.174,1.159 },
217 {23.26,17.15,11.52,8.049,6.375,4.114,2.792,2.155,
218 1.880,1.535,1.353,1.281,1.258,1.247,1.254,1.256,
219 1.252,1.234,1.212,1.194,1.183,1.170 },
220 {22.33,18.01,12.86,9.212,7.336,4.702,3.117,2.348,
221 2.015,1.602,1.385,1.297,1.268,1.251,1.256,1.258,
222 1.254,1.237,1.214,1.195,1.185,1.179 },
223 {33.91,24.13,15.71,10.80,8.507,5.467,3.692,2.808,
224 2.407,1.873,1.564,1.425,1.374,1.330,1.324,1.320,
225 1.312,1.288,1.258,1.235,1.221,1.205 },
226 {32.14,24.11,16.30,11.40,9.015,5.782,3.868,2.917,
227 2.490,1.925,1.596,1.447,1.391,1.342,1.332,1.327,
228 1.320,1.294,1.264,1.240,1.226,1.214 },
229 {29.51,24.07,17.19,12.28,9.766,6.238,4.112,3.066,
230 2.602,1.995,1.641,1.477,1.414,1.356,1.342,1.336,
231 1.328,1.302,1.270,1.245,1.231,1.233 },
232 {38.19,30.85,21.76,15.35,12.07,7.521,4.812,3.498,
233 2.926,2.188,1.763,1.563,1.484,1.405,1.382,1.371,
234 1.361,1.330,1.294,1.267,1.251,1.239 },
235 {49.71,39.80,27.96,19.63,15.36,9.407,5.863,4.155,
236 3.417,2.478,1.944,1.692,1.589,1.480,1.441,1.423,
237 1.409,1.372,1.330,1.298,1.280,1.258 },
238 {59.25,45.08,30.36,20.83,16.15,9.834,6.166,4.407,
239 3.641,2.648,2.064,1.779,1.661,1.531,1.482,1.459,
240 1.442,1.400,1.354,1.319,1.299,1.272 },
241 {56.38,44.29,30.50,21.18,16.51,10.11,6.354,4.542,
242 3.752,2.724,2.116,1.817,1.692,1.554,1.499,1.474,
243 1.456,1.412,1.364,1.328,1.307,1.282 }};
244
245 //data/corrections for T > Tlim
246 G4double Tlim = 10.*MeV;
247 G4double beta2lim = Tlim*(Tlim+2.*electron_mass_c2)/
248 ((Tlim+electron_mass_c2)*(Tlim+electron_mass_c2));
249 G4double bg2lim = Tlim*(Tlim+2.*electron_mass_c2)/
250 (electron_mass_c2*electron_mass_c2);
251
252 G4double sig0[15] = {0.2672*barn, 0.5922*barn, 2.653*barn, 6.235*barn,
253 11.69*barn , 13.24*barn , 16.12*barn, 23.00*barn ,
254 35.13*barn , 39.95*barn , 50.85*barn, 67.19*barn ,
255 91.15*barn , 104.4*barn , 113.1*barn};
256
257 G4double hecorr[15] = {120.70, 117.50, 105.00, 92.92, 79.23, 74.510, 68.29,
258 57.39, 41.97, 36.14, 24.53, 10.21, -7.855, -16.84,
259 -22.30};
260
261 G4double sigma;
262 SetParticle(part);
263
264 G4double Z23 = 2.*log(AtomicNumber)/3.; Z23 = exp(Z23);
265
266 // correction if particle .ne. e-/e+
267 // compute equivalent kinetic energy
268 // lambda depends on p*beta ....
269
270 G4double eKineticEnergy = KineticEnergy;
271
272 if(mass > electron_mass_c2)
273 {
274 G4double TAU = KineticEnergy/mass ;
275 G4double c = mass*TAU*(TAU+2.)/(electron_mass_c2*(TAU+1.)) ;
276 G4double w = c-2. ;
277 G4double tau = 0.5*(w+sqrt(w*w+4.*c)) ;
278 eKineticEnergy = electron_mass_c2*tau ;
279 }
280
281 G4double ChargeSquare = charge*charge;
282
283 G4double eTotalEnergy = eKineticEnergy + electron_mass_c2 ;
284 G4double beta2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2)
285 /(eTotalEnergy*eTotalEnergy);
286 G4double bg2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2)
287 /(electron_mass_c2*electron_mass_c2);
288
289 G4double eps = epsfactor*bg2/Z23;
290
291 if (eps<epsmin) sigma = 2.*eps*eps;
292 else if(eps<epsmax) sigma = log(1.+2.*eps)-2.*eps/(1.+2.*eps);
293 else sigma = log(2.*eps)-1.+1./eps;
294
295 sigma *= ChargeSquare*AtomicNumber*AtomicNumber/(beta2*bg2);
296
297 // interpolate in AtomicNumber and beta2
298 G4double c1,c2,cc1,cc2,corr;
299
300 // get bin number in Z
301 G4int iZ = 14;
302 while ((iZ>=0)&&(Zdat[iZ]>=AtomicNumber)) iZ -= 1;
303 if (iZ==14) iZ = 13;
304 if (iZ==-1) iZ = 0 ;
305
306 G4double Z1 = Zdat[iZ];
307 G4double Z2 = Zdat[iZ+1];
308 G4double ratZ = (AtomicNumber-Z1)*(AtomicNumber+Z1)/
309 ((Z2-Z1)*(Z2+Z1));
310
311 if(eKineticEnergy <= Tlim)
312 {
313 // get bin number in T (beta2)
314 G4int iT = 21;
315 while ((iT>=0)&&(Tdat[iT]>=eKineticEnergy)) iT -= 1;
316 if(iT==21) iT = 20;
317 if(iT==-1) iT = 0 ;
318
319 // calculate betasquare values
320 G4double T = Tdat[iT], E = T + electron_mass_c2;
321 G4double b2small = T*(E+electron_mass_c2)/(E*E);
322
323 T = Tdat[iT+1]; E = T + electron_mass_c2;
324 G4double b2big = T*(E+electron_mass_c2)/(E*E);
325 G4double ratb2 = (beta2-b2small)/(b2big-b2small);
326
327 if (charge < 0.)
328 {
329 c1 = celectron[iZ][iT];
330 c2 = celectron[iZ+1][iT];
331 cc1 = c1+ratZ*(c2-c1);
332
333 c1 = celectron[iZ][iT+1];
334 c2 = celectron[iZ+1][iT+1];
335 cc2 = c1+ratZ*(c2-c1);
336
337 corr = cc1+ratb2*(cc2-cc1);
338
339 sigma *= sigmafactor/corr;
340 }
341 else
342 {
343 c1 = cpositron[iZ][iT];
344 c2 = cpositron[iZ+1][iT];
345 cc1 = c1+ratZ*(c2-c1);
346
347 c1 = cpositron[iZ][iT+1];
348 c2 = cpositron[iZ+1][iT+1];
349 cc2 = c1+ratZ*(c2-c1);
350
351 corr = cc1+ratb2*(cc2-cc1);
352
353 sigma *= sigmafactor/corr;
354 }
355 }
356 else
357 {
358 c1 = bg2lim*sig0[iZ]*(1.+hecorr[iZ]*(beta2-beta2lim))/bg2;
359 c2 = bg2lim*sig0[iZ+1]*(1.+hecorr[iZ+1]*(beta2-beta2lim))/bg2;
360 if((AtomicNumber >= Z1) && (AtomicNumber <= Z2))
361 sigma = c1+ratZ*(c2-c1) ;
362 else if(AtomicNumber < Z1)
363 sigma = AtomicNumber*AtomicNumber*c1/(Z1*Z1);
364 else if(AtomicNumber > Z2)
365 sigma = AtomicNumber*AtomicNumber*c2/(Z2*Z2);
366 }
367 return sigma;
368
369}
370
371//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
372
373G4double G4UrbanMscModel90::ComputeTruePathLengthLimit(
374 const G4Track& track,
375 G4PhysicsTable* theTable,
376 G4double currentMinimalStep)
377{
378 tPathLength = currentMinimalStep;
379 const G4DynamicParticle* dp = track.GetDynamicParticle();
380 G4StepPoint* sp = track.GetStep()->GetPreStepPoint();
381 G4StepStatus stepStatus = sp->GetStepStatus();
382
383 if(stepStatus == fUndefined) {
384 inside = false;
385 insideskin = false;
386 tlimit = geombig;
387 SetParticle( dp->GetDefinition() );
388 }
389
390 theLambdaTable = theTable;
391 couple = track.GetMaterialCutsCouple();
392 currentMaterialIndex = couple->GetIndex();
393 currentKinEnergy = dp->GetKineticEnergy();
394 currentRange =
395 theManager->GetRangeFromRestricteDEDX(particle,currentKinEnergy,couple);
396 lambda0 = GetLambda(currentKinEnergy);
397
398 // stop here if small range particle
399 if(inside) return tPathLength;
400
401 if(tPathLength > currentRange) tPathLength = currentRange;
402
403 presafety = sp->GetSafety();
404 /*
405 G4cout << "G4UrbanMscModel90::ComputeTruePathLengthLimit tPathLength= "
406 <<tPathLength<<" safety= " << presafety
407 << " range= " <<currentRange<<G4endl;
408 */
409 // far from geometry boundary
410 if(currentRange < presafety)
411 {
412 inside = true;
413 return tPathLength;
414 }
415
416 // standard version
417 //
418 if (steppingAlgorithm == fUseDistanceToBoundary)
419 {
420 //compute geomlimit and presafety
421 GeomLimit(track);
422
423 // is far from boundary
424 if(currentRange <= presafety)
425 {
426 inside = true;
427 return tPathLength;
428 }
429
430 smallstep += 1.;
431 insideskin = false;
432
433 if((stepStatus == fGeomBoundary) || (stepStatus == fUndefined))
434 {
435
436 if(stepStatus == fUndefined) smallstep = 1.e10;
437 else smallstep = 1.;
438
439 // facrange scaling in lambda
440 // not so strong step restriction above lambdalimit
441 G4double facr = facrange;
442 if(lambda0 > lambdalimit)
443 facr *= frscaling1+frscaling2*lambda0/lambdalimit;
444
445 // constraint from the physics
446 if (currentRange > lambda0) tlimit = facr*currentRange;
447 else tlimit = facr*lambda0;
448
449 // constraint from the geometry (if tlimit above is too big)
450 G4double tgeom = geombig;
451 if(geomlimit > geommin)
452 {
453 if(stepStatus == fGeomBoundary)
454 tgeom = geomlimit/facgeom;
455 else
456 tgeom = 2.*geomlimit/facgeom;
457 }
458
459 //define stepmin here (it depends on lambda!)
460 //rough estimation of lambda_elastic/lambda_transport
461 G4double rat = currentKinEnergy/MeV ;
462 rat = 1.e-3/(rat*(10.+rat)) ;
463 //stepmin ~ lambda_elastic
464 stepmin = rat*lambda0;
465 skindepth = skin*stepmin;
466
467 //define tlimitmin
468 tlimitmin = lambda0/nstepmax;
469 if(tlimitmin < stepmin) tlimitmin = 1.01*stepmin;
470 if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix;
471
472 //lower limit for tlimit
473 if(tlimit < tlimitmin) tlimit = tlimitmin;
474
475 //check against geometry limit
476 if(tlimit > tgeom) tlimit = tgeom;
477 }
478
479 //if track starts far from boundaries increase tlimit!
480 if(tlimit < facsafety*presafety) tlimit = facsafety*presafety ;
481
482 // G4cout << "tgeom= " << tgeom << " geomlimit= " << geomlimit
483 // << " tlimit= " << tlimit << " presafety= " << presafety << G4endl;
484
485 // shortcut
486 if((tPathLength < tlimit) && (tPathLength < presafety))
487 return tPathLength;
488
489 G4double tnow = tlimit;
490 // optimization ...
491 if(geomlimit < geombig) tnow = max(tlimit,facsafety*geomlimit);
492
493 // step reduction near to boundary
494 if(smallstep < skin)
495 {
496 tnow = stepmin;
497 insideskin = true;
498 }
499 else if(geomlimit < geombig)
500 {
501 if(geomlimit > skindepth)
502 {
503 if(tnow > geomlimit-0.999*skindepth)
504 tnow = geomlimit-0.999*skindepth;
505 }
506 else
507 {
508 insideskin = true;
509 if(tnow > stepmin) tnow = stepmin;
510 }
511 }
512
513 if(tnow < stepmin) tnow = stepmin;
514
515 if(tPathLength > tnow) tPathLength = tnow ;
516 }
517 // for 'normal' simulation with or without magnetic field
518 // there no small step/single scattering at boundaries
519 else if(steppingAlgorithm == fUseSafety)
520 {
521 // compute presafety again if presafety <= 0 and no boundary
522 // i.e. when it is needed for optimization purposes
523 if((stepStatus != fGeomBoundary) && (presafety < tlimitminfix))
524 presafety = safetyHelper->ComputeSafety(sp->GetPosition());
525
526 // is far from boundary
527 if(currentRange < presafety)
528 {
529 inside = true;
530 return tPathLength;
531 }
532
533 if((stepStatus == fGeomBoundary) || (stepStatus == fUndefined))
534 {
535 // facrange scaling in lambda
536 // not so strong step restriction above lambdalimit
537 G4double facr = facrange;
538 if(lambda0 > lambdalimit)
539 facr *= frscaling1+frscaling2*lambda0/lambdalimit;
540
541 // constraint from the physics
542 if (currentRange > lambda0) tlimit = facr*currentRange;
543 else tlimit = facr*lambda0;
544
545 //lower limit for tlimit
546 tlimitmin = std::max(tlimitminfix,lambda0/nstepmax);
547 if(tlimit < tlimitmin) tlimit = tlimitmin;
548 }
549
550 //if track starts far from boundaries increase tlimit!
551 if(tlimit < facsafety*presafety) tlimit = facsafety*presafety ;
552
553 if(tPathLength > tlimit) tPathLength = tlimit;
554 }
555
556 // version similar to 7.1 (needed for some experiments)
557 else
558 {
559 if (stepStatus == fGeomBoundary)
560 {
561 if (currentRange > lambda0) tlimit = facrange*currentRange;
562 else tlimit = facrange*lambda0;
563
564 if(tlimit < tlimitmin) tlimit = tlimitmin;
565 if(tPathLength > tlimit) tPathLength = tlimit;
566 }
567 }
568 // G4cout << "tPathLength= " << tPathLength << " geomlimit= " << geomlimit
569 // << " currentMinimalStep= " << currentMinimalStep << G4endl;
570 return tPathLength ;
571}
572
573//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
574
575void G4UrbanMscModel90::GeomLimit(const G4Track& track)
576{
577 geomlimit = geombig;
578
579 // no geomlimit for the World volume
580 if((track.GetVolume() != 0) &&
581 (track.GetVolume() != safetyHelper->GetWorldVolume()))
582 {
583 G4double cstep = currentRange;
584 geomlimit = safetyHelper->CheckNextStep(
585 track.GetStep()->GetPreStepPoint()->GetPosition(),
586 track.GetMomentumDirection(),
587 cstep,
588 presafety);
589 // G4cout << "!!!G4UrbanMscModel90::GeomLimit presafety= " << presafety
590 // << " limit= " << geomlimit << G4endl;
591 }
592}
593
594//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
595
596G4double G4UrbanMscModel90::ComputeGeomPathLength(G4double)
597{
598 lambdaeff = lambda0;
599 par1 = -1. ;
600 par2 = par3 = 0. ;
601
602 // do the true -> geom transformation
603 zPathLength = tPathLength;
604
605 // z = t for very small tPathLength
606 if(tPathLength < tlimitminfix) return zPathLength;
607
608 // this correction needed to run MSC with eIoni and eBrem inactivated
609 // and makes no harm for a normal run
610 if(tPathLength > currentRange)
611 tPathLength = currentRange ;
612
613 G4double tau = tPathLength/lambda0 ;
614
615 if ((tau <= tausmall) || insideskin) {
616 zPathLength = tPathLength;
617 if(zPathLength > lambda0) zPathLength = lambda0;
618 return zPathLength;
619 }
620
621 G4double zmean = tPathLength;
622 if (tPathLength < currentRange*dtrl) {
623 if(tau < taulim) zmean = tPathLength*(1.-0.5*tau) ;
624 else zmean = lambda0*(1.-exp(-tau));
625 } else if(currentKinEnergy < mass) {
626 par1 = 1./currentRange ;
627 par2 = 1./(par1*lambda0) ;
628 par3 = 1.+par2 ;
629 if(tPathLength < currentRange)
630 zmean = (1.-exp(par3*log(1.-tPathLength/currentRange)))/(par1*par3) ;
631 else
632 zmean = 1./(par1*par3) ;
633 } else {
634 G4double T1 = theManager->GetEnergy(particle,currentRange-tPathLength,couple);
635 G4double lambda1 = GetLambda(T1);
636
637 par1 = (lambda0-lambda1)/(lambda0*tPathLength) ;
638 par2 = 1./(par1*lambda0) ;
639 par3 = 1.+par2 ;
640 zmean = (1.-exp(par3*log(lambda1/lambda0)))/(par1*par3) ;
641 }
642
643 zPathLength = zmean ;
644
645 // sample z
646 if(samplez)
647 {
648 const G4double ztmax = 0.99, onethird = 1./3. ;
649 G4double zt = zmean/tPathLength ;
650
651 if (tPathLength > stepmin && zt < ztmax)
652 {
653 G4double u,cz1;
654 if(zt >= onethird)
655 {
656 G4double cz = 0.5*(3.*zt-1.)/(1.-zt) ;
657 cz1 = 1.+cz ;
658 G4double u0 = cz/cz1 ;
659 G4double grej ;
660 do {
661 u = exp(log(G4UniformRand())/cz1) ;
662 grej = exp(cz*log(u/u0))*(1.-u)/(1.-u0) ;
663 } while (grej < G4UniformRand()) ;
664 }
665 else
666 {
667 cz1 = 1./zt-1.;
668 u = 1.-exp(log(G4UniformRand())/cz1) ;
669 }
670 zPathLength = tPathLength*u ;
671 }
672 }
673
674 if(zPathLength > lambda0) zPathLength = lambda0;
675
676 return zPathLength;
677}
678
679//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
680
681G4double G4UrbanMscModel90::ComputeTrueStepLength(G4double geomStepLength)
682{
683 // step defined other than transportation
684 if(geomStepLength == zPathLength && tPathLength <= currentRange)
685 return tPathLength;
686
687 // t = z for very small step
688 zPathLength = geomStepLength;
689 tPathLength = geomStepLength;
690 if(geomStepLength < tlimitminfix) return tPathLength;
691
692 // recalculation
693 if((geomStepLength > lambda0*tausmall) && !insideskin)
694 {
695 if(par1 < 0.)
696 tPathLength = -lambda0*log(1.-geomStepLength/lambda0) ;
697 else
698 {
699 if(par1*par3*geomStepLength < 1.)
700 tPathLength = (1.-exp(log(1.-par1*par3*geomStepLength)/par3))/par1 ;
701 else
702 tPathLength = currentRange;
703 }
704 }
705 if(tPathLength < geomStepLength) tPathLength = geomStepLength;
706
707 return tPathLength;
708}
709
710//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
711
712G4double G4UrbanMscModel90::ComputeTheta0(G4double trueStepLength,
713 G4double KineticEnergy)
714{
715 // for all particles take the width of the central part
716 // from a parametrization similar to the Highland formula
717 // ( Highland formula: Particle Physics Booklet, July 2002, eq. 26.10)
718 const G4double c_highland = 13.6*MeV ;
719 G4double betacp = sqrt(currentKinEnergy*(currentKinEnergy+2.*mass)*
720 KineticEnergy*(KineticEnergy+2.*mass)/
721 ((currentKinEnergy+mass)*(KineticEnergy+mass)));
722 G4double y = trueStepLength/currentRadLength;
723 G4double theta0 = c_highland*std::abs(charge)*sqrt(y)/betacp;
724 y = log(y);
725 theta0 *= sqrt(1.+y*(0.105+0.0035*y));
726
727 //correction for small Zeff (based on high energy
728 // proton scattering data)
729 // see G.Shen at al. Phys.Rev.D20(1979) p.1584
730 theta0 *= 1.-0.24/(Zeff*(Zeff+1.));
731
732 return theta0;
733
734}
735
736//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
737
738void G4UrbanMscModel90::SampleScattering(const G4DynamicParticle* dynParticle,
739 G4double safety)
740{
741 G4double kineticEnergy = dynParticle->GetKineticEnergy();
742 if((kineticEnergy <= 0.0) || (tPathLength <= tlimitminfix) ||
743 (tPathLength/tausmall < lambda0) ) return;
744
745 G4double cth = SampleCosineTheta(tPathLength,kineticEnergy);
746 // protection against 'bad' cth values
747 if(std::abs(cth) > 1.) return;
748
749 G4double sth = sqrt((1.0 - cth)*(1.0 + cth));
750 G4double phi = twopi*G4UniformRand();
751 G4double dirx = sth*cos(phi);
752 G4double diry = sth*sin(phi);
753
754 G4ThreeVector oldDirection = dynParticle->GetMomentumDirection();
755 G4ThreeVector newDirection(dirx,diry,cth);
756 newDirection.rotateUz(oldDirection);
757 fParticleChange->ProposeMomentumDirection(newDirection);
758
759 if (latDisplasment && safety > tlimitminfix) {
760
761 G4double r = SampleDisplacement();
762/*
763 G4cout << "G4UrbanMscModel90::SampleSecondaries: e(MeV)= " << kineticEnergy
764 << " sinTheta= " << sth << " r(mm)= " << r
765 << " trueStep(mm)= " << truestep
766 << " geomStep(mm)= " << zPathLength
767 << G4endl;
768*/
769 if(r > 0.)
770 {
771 G4double latcorr = LatCorrelation();
772 if(latcorr > r) latcorr = r;
773
774 // sample direction of lateral displacement
775 // compute it from the lateral correlation
776 G4double Phi = 0.;
777 if(std::abs(r*sth) < latcorr) {
778 Phi = twopi*G4UniformRand();
779 } else {
780 G4double psi = std::acos(latcorr/(r*sth));
781 if(G4UniformRand() < 0.5) Phi = phi+psi;
782 else Phi = phi-psi;
783 }
784
785 dirx = std::cos(Phi);
786 diry = std::sin(Phi);
787
788 G4ThreeVector latDirection(dirx,diry,0.0);
789 latDirection.rotateUz(oldDirection);
790
791 G4ThreeVector Position = *(fParticleChange->GetProposedPosition());
792 G4double fac = 1.;
793 if(r > safety) {
794 // ******* so safety is computed at boundary too ************
795 G4double newsafety = safetyHelper->ComputeSafety(Position);
796 //G4double newsafety = safety;
797 if(r > newsafety)
798 fac = newsafety/r ;
799 }
800
801 if(fac > 0.)
802 {
803 // compute new endpoint of the Step
804 G4ThreeVector newPosition = Position+fac*r*latDirection;
805
806 // definetly not on boundary
807 if(1. == fac) {
808 //if(0. < fac) {
809 safetyHelper->ReLocateWithinVolume(newPosition);
810
811
812 } else {
813 // check safety after displacement
814 G4double postsafety = safetyHelper->ComputeSafety(newPosition);
815
816 // displacement to boundary
817 if(postsafety <= 0.) {
818 safetyHelper->Locate(newPosition, newDirection);
819
820 // not on the boundary
821 } else {
822 safetyHelper->ReLocateWithinVolume(newPosition);
823 }
824 }
825 fParticleChange->ProposePosition(newPosition);
826 }
827 }
828 }
829}
830
831//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
832
833G4double G4UrbanMscModel90::SampleCosineTheta(G4double trueStepLength,
834 G4double KineticEnergy)
835{
836 G4double cth = 1. ;
837 G4double tau = trueStepLength/lambda0 ;
838
839 Zeff = couple->GetMaterial()->GetTotNbOfElectPerVolume()/
840 couple->GetMaterial()->GetTotNbOfAtomsPerVolume() ;
841
842 if(insideskin)
843 {
844 //no scattering, single or plural scattering
845 G4double mean = trueStepLength/stepmin ;
846
847 G4int n = G4Poisson(mean);
848 if(n > 0)
849 {
850 G4double tm = KineticEnergy/electron_mass_c2;
851 // ascr - screening parameter
852 G4double ascr = exp(log(Zeff)/3.)/(137.*sqrt(tm*(tm+2.)));
853 G4double ascr1 = 1.+0.5*ascr*ascr;
854 G4double bp1=ascr1+1.;
855 G4double bm1=ascr1-1.;
856 // single scattering from screened Rutherford x-section
857 G4double ct,st,phi;
858 G4double sx=0.,sy=0.,sz=0.;
859 for(G4int i=1; i<=n; i++)
860 {
861 ct = ascr1-bp1*bm1/(2.*G4UniformRand()+bm1);
862 if(ct < -1.) ct = -1.;
863 if(ct > 1.) ct = 1.;
864 st = sqrt(1.-ct*ct);
865 phi = twopi*G4UniformRand();
866 sx += st*cos(phi);
867 sy += st*sin(phi);
868 sz += ct;
869 }
870 cth = sz/sqrt(sx*sx+sy*sy+sz*sz);
871 }
872 }
873 else
874 {
875 if(trueStepLength >= currentRange*dtrl) {
876 if(par1*trueStepLength < 1.)
877 tau = -par2*log(1.-par1*trueStepLength) ;
878 // for the case if ioni/brems are inactivated
879 // see the corresponding condition in ComputeGeomPathLength
880 else if(1.-KineticEnergy/currentKinEnergy > taulim)
881 tau = taubig ;
882 }
883 currentTau = tau ;
884 lambdaeff = trueStepLength/currentTau;
885 currentRadLength = couple->GetMaterial()->GetRadlen();
886
887 if (tau >= taubig) cth = -1.+2.*G4UniformRand();
888 else if (tau >= tausmall)
889 {
890 G4double b,bx,b1,ebx,eb1;
891 G4double prob = 0., qprob = 1. ;
892 G4double a = 1., ea = 0., eaa = 1.;
893 G4double xmean1 = 1., xmean2 = 0.;
894 G4double xsi = 3.;
895
896 G4double theta0 = ComputeTheta0(trueStepLength,KineticEnergy);
897
898 // protexction for very small angles
899 if(theta0 < tausmall) return cth;
900
901 G4double sth = sin(0.5*theta0);
902 a = 0.25/(sth*sth);
903
904 G4double xmeanth = exp(-tau);
905
906 G4double c = 3. ;
907 G4double c1 = c-1.;
908
909 G4double x0 = 1.-xsi/a ;
910 if(x0 < 0.)
911 {
912 // 1 model function
913 b = exp(tau);
914 bx = b-1.;
915 b1 = b+1.;
916 ebx=exp((c1)*log(bx)) ;
917 eb1=exp((c1)*log(b1)) ;
918 }
919 else
920 {
921 //empirical tail parameter
922 // based some exp. data
923 c = 2.40-0.027*exp(2.*log(Zeff)/3.);
924
925 if(c == 2.) c = 2.+taulim ;
926 if(c <= 1.) c = 1.+taulim ;
927 c1 = c-1.;
928
929 ea = exp(-xsi) ;
930 eaa = 1.-ea ;
931 xmean1 = 1.-(1.-(1.+xsi)*ea)/(eaa*a) ;
932
933 // from the continuity of the 1st derivative at x=x0
934 b = 1.+(c-xsi)/a ;
935
936 b1 = b+1. ;
937 bx = c/a ;
938 eb1=exp((c1)*log(b1)) ;
939 ebx=exp((c1)*log(bx)) ;
940 xmean2 = (x0*eb1+ebx-(eb1*bx-b1*ebx)/(c-2.))/(eb1-ebx) ;
941
942 G4double f1x0 = a*ea/eaa ;
943 G4double f2x0 = c1*eb1*ebx/(eb1-ebx)/exp(c*log(bx)) ;
944
945 // from continuity at x=x0
946 prob = f2x0/(f1x0+f2x0) ;
947
948 // from xmean = xmeanth
949 qprob = (f1x0+f2x0)*xmeanth/(f2x0*xmean1+f1x0*xmean2) ;
950 }
951
952 // sampling of costheta
953 if (G4UniformRand() < qprob)
954 {
955 if (G4UniformRand() < prob)
956 cth = 1.+log(ea+G4UniformRand()*eaa)/a ;
957 else
958 cth = b-b1*bx/exp(log(ebx-G4UniformRand()*(ebx-eb1))/c1) ;
959 }
960 else
961 {
962 cth = -1.+2.*G4UniformRand();
963 }
964 }
965 }
966
967 return cth ;
968}
969//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
970
971G4double G4UrbanMscModel90::SampleDisplacement()
972{
973 const G4double kappa = 2.5;
974 const G4double kappapl1 = kappa+1.;
975 const G4double kappami1 = kappa-1.;
976 G4double rmean = 0.0;
977 if ((currentTau >= tausmall) && !insideskin) {
978 if (currentTau < taulim) {
979 rmean = kappa*currentTau*currentTau*currentTau*
980 (1.-kappapl1*currentTau*0.25)/6. ;
981
982 } else {
983 G4double etau = 0.0;
984 if (currentTau<taubig) etau = exp(-currentTau);
985 rmean = -kappa*currentTau;
986 rmean = -exp(rmean)/(kappa*kappami1);
987 rmean += currentTau-kappapl1/kappa+kappa*etau/kappami1;
988 }
989 if (rmean>0.) rmean = 2.*lambdaeff*sqrt(rmean/3.0);
990 else rmean = 0.;
991 }
992
993 // protection against z > t ...........................
994 if(rmean > 0.) {
995 G4double zt = (tPathLength-zPathLength)*(tPathLength+zPathLength);
996 if(zt <= 0.)
997 rmean = 0.;
998 else if(rmean*rmean > zt)
999 rmean = sqrt(zt);
1000 }
1001 return rmean;
1002}
1003
1004//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
1005
1006G4double G4UrbanMscModel90::LatCorrelation()
1007{
1008 const G4double kappa = 2.5;
1009 const G4double kappami1 = kappa-1.;
1010
1011 G4double latcorr = 0.;
1012 if((currentTau >= tausmall) && !insideskin)
1013 {
1014 if(currentTau < taulim)
1015 latcorr = lambdaeff*kappa*currentTau*currentTau*
1016 (1.-(kappa+1.)*currentTau/3.)/3.;
1017 else
1018 {
1019 G4double etau = 0.;
1020 if(currentTau < taubig) etau = exp(-currentTau);
1021 latcorr = -kappa*currentTau;
1022 latcorr = exp(latcorr)/kappami1;
1023 latcorr += 1.-kappa*etau/kappami1 ;
1024 latcorr *= 2.*lambdaeff/3. ;
1025 }
1026 }
1027
1028 return latcorr;
1029}
1030
1031//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
1032
1033void G4UrbanMscModel90::SampleSecondaries(std::vector<G4DynamicParticle*>*,
1034 const G4MaterialCutsCouple*,
1035 const G4DynamicParticle*,
1036 G4double,
1037 G4double)
1038{}
1039
1040//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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