source: trunk/source/processes/hadronic/models/coherent_elastic/include/G4DiffuseElastic.hh@ 1036

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25//
26//
27// $Id: G4DiffuseElastic.hh,v 1.13 2007/11/06 17:01:20 grichine Exp $
28// GEANT4 tag $Name: geant4-09-02 $
29//
30//
31// G4 Model: optical elastic scattering with 4-momentum balance
32//
33// Class Description
34// Final state production model for hadron nuclear elastic scattering;
35// Class Description - End
36//
37//
38// 24.05.07 V. Grichine first implementation for hadron (no Coulomb) elastic scattering
39// 04.09.07 V. Grichine implementation for Coulomb elastic scattering
40
41
42#ifndef G4DiffuseElastic_h
43#define G4DiffuseElastic_h 1
44
45#include "globals.hh"
46#include "G4HadronicInteraction.hh"
47#include "G4HadProjectile.hh"
48#include "G4Nucleus.hh"
49
50using namespace std;
51
52class G4ParticleDefinition;
53class G4PhysicsTable;
54class G4PhysicsLogVector;
55
56class G4DiffuseElastic : public G4HadronicInteraction
57{
58public:
59
60 G4DiffuseElastic();
61
62 G4DiffuseElastic(const G4ParticleDefinition* aParticle);
63
64
65
66
67
68 virtual ~G4DiffuseElastic();
69
70 void Initialise();
71
72 void InitialiseOnFly(G4double Z, G4double A);
73
74 void BuildAngleTable();
75
76
77 G4HadFinalState * ApplyYourself(const G4HadProjectile & aTrack,
78 G4Nucleus & targetNucleus);
79
80
81 void SetPlabLowLimit(G4double value);
82
83 void SetHEModelLowLimit(G4double value);
84
85 void SetQModelLowLimit(G4double value);
86
87 void SetLowestEnergyLimit(G4double value);
88
89 void SetRecoilKinEnergyLimit(G4double value);
90
91 G4double SampleT(const G4ParticleDefinition* aParticle,
92 G4double p, G4double A);
93
94 G4double SampleTableT(const G4ParticleDefinition* aParticle,
95 G4double p, G4double Z, G4double A);
96
97 G4double SampleThetaCMS(const G4ParticleDefinition* aParticle, G4double p, G4double A);
98
99 G4double SampleTableThetaCMS(const G4ParticleDefinition* aParticle, G4double p,
100 G4double Z, G4double A);
101
102 G4double GetScatteringAngle(G4int iMomentum, G4int iAngle, G4double position);
103
104 G4double SampleThetaLab(const G4HadProjectile* aParticle,
105 G4double tmass, G4double A);
106
107 G4double GetDiffuseElasticXsc( const G4ParticleDefinition* particle,
108 G4double theta,
109 G4double momentum,
110 G4double A );
111
112 G4double GetInvElasticXsc( const G4ParticleDefinition* particle,
113 G4double theta,
114 G4double momentum,
115 G4double A, G4double Z );
116
117 G4double GetDiffuseElasticSumXsc( const G4ParticleDefinition* particle,
118 G4double theta,
119 G4double momentum,
120 G4double A, G4double Z );
121
122 G4double GetInvElasticSumXsc( const G4ParticleDefinition* particle,
123 G4double tMand,
124 G4double momentum,
125 G4double A, G4double Z );
126
127 G4double IntegralElasticProb( const G4ParticleDefinition* particle,
128 G4double theta,
129 G4double momentum,
130 G4double A );
131
132
133 G4double GetCoulombElasticXsc( const G4ParticleDefinition* particle,
134 G4double theta,
135 G4double momentum,
136 G4double Z );
137
138 G4double GetInvCoulombElasticXsc( const G4ParticleDefinition* particle,
139 G4double tMand,
140 G4double momentum,
141 G4double A, G4double Z );
142
143 G4double GetCoulombTotalXsc( const G4ParticleDefinition* particle,
144 G4double momentum, G4double Z );
145
146 G4double GetCoulombIntegralXsc( const G4ParticleDefinition* particle,
147 G4double momentum, G4double Z,
148 G4double theta1, G4double theta2 );
149
150
151 G4double CalculateParticleBeta( const G4ParticleDefinition* particle,
152 G4double momentum );
153
154 G4double CalculateZommerfeld( G4double beta, G4double Z1, G4double Z2 );
155
156 G4double CalculateAm( G4double momentum, G4double n, G4double Z);
157
158 G4double CalculateNuclearRad( G4double A);
159
160 G4double ThetaCMStoThetaLab(const G4DynamicParticle* aParticle,
161 G4double tmass, G4double thetaCMS);
162
163 G4double ThetaLabToThetaCMS(const G4DynamicParticle* aParticle,
164 G4double tmass, G4double thetaLab);
165
166
167
168
169
170 G4double BesselJzero(G4double z);
171 G4double BesselJone(G4double z);
172 G4double DampFactor(G4double z);
173 G4double BesselOneByArg(G4double z);
174
175 G4double GetDiffElasticProb(G4double theta);
176 G4double GetDiffElasticSumProb(G4double theta);
177 G4double GetIntegrandFunction(G4double theta);
178
179
180 G4double GetNuclearRadius(){return fNuclearRadius;};
181
182private:
183
184
185 G4ParticleDefinition* theProton;
186 G4ParticleDefinition* theNeutron;
187 G4ParticleDefinition* theDeuteron;
188 G4ParticleDefinition* theAlpha;
189
190 const G4ParticleDefinition* thePionPlus;
191 const G4ParticleDefinition* thePionMinus;
192
193 G4double lowEnergyRecoilLimit;
194 G4double lowEnergyLimitHE;
195 G4double lowEnergyLimitQ;
196 G4double lowestEnergyLimit;
197 G4double plabLowLimit;
198
199 G4int fEnergyBin;
200 G4int fAngleBin;
201
202 G4PhysicsLogVector* fEnergyVector;
203 G4PhysicsTable* fAngleTable;
204 std::vector<G4PhysicsTable*> fAngleBank;
205
206 std::vector<G4double> fElementNumberVector;
207 std::vector<G4String> fElementNameVector;
208
209 const G4ParticleDefinition* fParticle;
210 G4double fWaveVector;
211 G4double fAtomicWeight;
212 G4double fAtomicNumber;
213 G4double fNuclearRadius;
214 G4double fBeta;
215 G4double fZommerfeld;
216 G4double fAm;
217 G4bool fAddCoulomb;
218
219};
220
221
222inline void G4DiffuseElastic::SetRecoilKinEnergyLimit(G4double value)
223{
224 lowEnergyRecoilLimit = value;
225}
226
227inline void G4DiffuseElastic::SetPlabLowLimit(G4double value)
228{
229 plabLowLimit = value;
230}
231
232inline void G4DiffuseElastic::SetHEModelLowLimit(G4double value)
233{
234 lowEnergyLimitHE = value;
235}
236
237inline void G4DiffuseElastic::SetQModelLowLimit(G4double value)
238{
239 lowEnergyLimitQ = value;
240}
241
242inline void G4DiffuseElastic::SetLowestEnergyLimit(G4double value)
243{
244 lowestEnergyLimit = value;
245}
246
247
248/////////////////////////////////////////////////////////////
249//
250// Bessel J0 function based on rational approximation from
251// J.F. Hart, Computer Approximations, New York, Willey 1968, p. 141
252
253inline G4double G4DiffuseElastic::BesselJzero(G4double value)
254{
255 G4double modvalue, value2, fact1, fact2, arg, shift, bessel;
256
257 modvalue = fabs(value);
258
259 if ( value < 8.0 && value > -8.0 )
260 {
261 value2 = value*value;
262
263 fact1 = 57568490574.0 + value2*(-13362590354.0
264 + value2*( 651619640.7
265 + value2*(-11214424.18
266 + value2*( 77392.33017
267 + value2*(-184.9052456 ) ) ) ) );
268
269 fact2 = 57568490411.0 + value2*( 1029532985.0
270 + value2*( 9494680.718
271 + value2*(59272.64853
272 + value2*(267.8532712
273 + value2*1.0 ) ) ) );
274
275 bessel = fact1/fact2;
276 }
277 else
278 {
279 arg = 8.0/modvalue;
280
281 value2 = arg*arg;
282
283 shift = modvalue-0.785398164;
284
285 fact1 = 1.0 + value2*(-0.1098628627e-2
286 + value2*(0.2734510407e-4
287 + value2*(-0.2073370639e-5
288 + value2*0.2093887211e-6 ) ) );
289
290 fact2 = -0.1562499995e-1 + value2*(0.1430488765e-3
291 + value2*(-0.6911147651e-5
292 + value2*(0.7621095161e-6
293 - value2*0.934945152e-7 ) ) );
294
295 bessel = sqrt(0.636619772/modvalue)*(cos(shift)*fact1 - arg*sin(shift)*fact2 );
296 }
297 return bessel;
298}
299
300/////////////////////////////////////////////////////////////
301//
302// Bessel J1 function based on rational approximation from
303// J.F. Hart, Computer Approximations, New York, Willey 1968, p. 141
304
305inline G4double G4DiffuseElastic::BesselJone(G4double value)
306{
307 G4double modvalue, value2, fact1, fact2, arg, shift, bessel;
308
309 modvalue = fabs(value);
310
311 if ( modvalue < 8.0 )
312 {
313 value2 = value*value;
314
315 fact1 = value*(72362614232.0 + value2*(-7895059235.0
316 + value2*( 242396853.1
317 + value2*(-2972611.439
318 + value2*( 15704.48260
319 + value2*(-30.16036606 ) ) ) ) ) );
320
321 fact2 = 144725228442.0 + value2*(2300535178.0
322 + value2*(18583304.74
323 + value2*(99447.43394
324 + value2*(376.9991397
325 + value2*1.0 ) ) ) );
326 bessel = fact1/fact2;
327 }
328 else
329 {
330 arg = 8.0/modvalue;
331
332 value2 = arg*arg;
333
334 shift = modvalue - 2.356194491;
335
336 fact1 = 1.0 + value2*( 0.183105e-2
337 + value2*(-0.3516396496e-4
338 + value2*(0.2457520174e-5
339 + value2*(-0.240337019e-6 ) ) ) );
340
341 fact2 = 0.04687499995 + value2*(-0.2002690873e-3
342 + value2*( 0.8449199096e-5
343 + value2*(-0.88228987e-6
344 + value2*0.105787412e-6 ) ) );
345
346 bessel = sqrt( 0.636619772/modvalue)*(cos(shift)*fact1 - arg*sin(shift)*fact2);
347
348 if (value < 0.0) bessel = -bessel;
349 }
350 return bessel;
351}
352
353////////////////////////////////////////////////////////////////////
354//
355// damp factor in diffraction x/sh(x), x was already *pi
356
357inline G4double G4DiffuseElastic::DampFactor(G4double x)
358{
359 G4double df;
360 G4double f2 = 2., f3 = 6., f4 = 24.; // first factorials
361
362 // x *= pi;
363
364 if( std::fabs(x) < 0.01 )
365 {
366 df = 1./(1. + x/f2 + x*x/f3 + x*x*x/f4);
367 }
368 else
369 {
370 df = x/std::sinh(x);
371 }
372 return df;
373}
374
375
376////////////////////////////////////////////////////////////////////
377//
378// return J1(x)/x with special case for small x
379
380inline G4double G4DiffuseElastic::BesselOneByArg(G4double x)
381{
382 G4double x2, result;
383
384 if( std::fabs(x) < 0.01 )
385 {
386 x *= 0.5;
387 x2 = x*x;
388 result = 2. - x2 + x2*x2/6.;
389 }
390 else
391 {
392 result = BesselJone(x)/x;
393 }
394 return result;
395}
396
397////////////////////////////////////////////////////////////////////
398//
399// return particle beta
400
401inline G4double G4DiffuseElastic::CalculateParticleBeta( const G4ParticleDefinition* particle,
402 G4double momentum )
403{
404 G4double mass = particle->GetPDGMass();
405 G4double a = momentum/mass;
406 fBeta = a/std::sqrt(1+a*a);
407
408 return fBeta;
409}
410
411////////////////////////////////////////////////////////////////////
412//
413// return Zommerfeld parameter for Coulomb scattering
414
415inline G4double G4DiffuseElastic::CalculateZommerfeld( G4double beta, G4double Z1, G4double Z2 )
416{
417 fZommerfeld = fine_structure_const*Z1*Z2/beta;
418
419 return fZommerfeld;
420}
421
422////////////////////////////////////////////////////////////////////
423//
424// return Wentzel correction for Coulomb scattering
425
426inline G4double G4DiffuseElastic::CalculateAm( G4double momentum, G4double n, G4double Z)
427{
428 G4double k = momentum/hbarc;
429 G4double ch = 1.13 + 3.76*n*n;
430 G4double zn = 1.77*k*std::pow(Z,-1./3.)*Bohr_radius;
431 G4double zn2 = zn*zn;
432 fAm = ch/zn2;
433
434 return fAm;
435}
436
437////////////////////////////////////////////////////////////////////
438//
439// calculate nuclear radius for different atomic weights using different approximations
440
441inline G4double G4DiffuseElastic::CalculateNuclearRad( G4double A)
442{
443 G4double r0;
444
445 if(A < 50.)
446 {
447 if(A > 10.) r0 = 1.16*( 1 - std::pow(A, -2./3.) )*fermi; // 1.08*fermi;
448 else r0 = 1.1*fermi;
449
450 fNuclearRadius = r0*std::pow(A, 1./3.);
451 }
452 else
453 {
454 r0 = 1.7*fermi;
455
456 fNuclearRadius = r0*std::pow(A, 0.27);
457 }
458 return fNuclearRadius;
459}
460
461////////////////////////////////////////////////////////////////////
462//
463// return Coulomb scattering differential xsc with Wentzel correction
464
465inline G4double G4DiffuseElastic::GetCoulombElasticXsc( const G4ParticleDefinition* particle,
466 G4double theta,
467 G4double momentum,
468 G4double Z )
469{
470 G4double sinHalfTheta = std::sin(0.5*theta);
471 G4double sinHalfTheta2 = sinHalfTheta*sinHalfTheta;
472 G4double beta = CalculateParticleBeta( particle, momentum);
473 G4double z = particle->GetPDGCharge();
474 G4double n = CalculateZommerfeld( beta, z, Z );
475 G4double am = CalculateAm( momentum, n, Z);
476 G4double k = momentum/hbarc;
477 G4double ch = 0.5*n/k;
478 G4double ch2 = ch*ch;
479 G4double xsc = ch2/(sinHalfTheta2+am)/(sinHalfTheta2+am);
480
481 return xsc;
482}
483
484
485////////////////////////////////////////////////////////////////////
486//
487// return Coulomb scattering total xsc with Wentzel correction
488
489inline G4double G4DiffuseElastic::GetCoulombTotalXsc( const G4ParticleDefinition* particle,
490 G4double momentum, G4double Z )
491{
492 G4double beta = CalculateParticleBeta( particle, momentum);
493 G4cout<<"beta = "<<beta<<G4endl;
494 G4double z = particle->GetPDGCharge();
495 G4double n = CalculateZommerfeld( beta, z, Z );
496 G4cout<<"fZomerfeld = "<<n<<G4endl;
497 G4double am = CalculateAm( momentum, n, Z);
498 G4cout<<"cof Am = "<<am<<G4endl;
499 G4double k = momentum/hbarc;
500 G4cout<<"k = "<<k*fermi<<" 1/fermi"<<G4endl;
501 G4cout<<"k*Bohr_radius = "<<k*Bohr_radius<<G4endl;
502 G4double ch = n/k;
503 G4double ch2 = ch*ch;
504 G4double xsc = ch2*pi/(am +am*am);
505
506 return xsc;
507}
508
509////////////////////////////////////////////////////////////////////
510//
511// return Coulomb scattering xsc with Wentzel correction integrated between
512// theta1 and < theta2
513
514inline G4double G4DiffuseElastic::GetCoulombIntegralXsc( const G4ParticleDefinition* particle,
515 G4double momentum, G4double Z,
516 G4double theta1, G4double theta2 )
517{
518 G4double c1 = std::cos(theta1);
519 G4cout<<"c1 = "<<c1<<G4endl;
520 G4double c2 = std::cos(theta2);
521 G4cout<<"c2 = "<<c2<<G4endl;
522 G4double beta = CalculateParticleBeta( particle, momentum);
523 // G4cout<<"beta = "<<beta<<G4endl;
524 G4double z = particle->GetPDGCharge();
525 G4double n = CalculateZommerfeld( beta, z, Z );
526 // G4cout<<"fZomerfeld = "<<n<<G4endl;
527 G4double am = CalculateAm( momentum, n, Z);
528 // G4cout<<"cof Am = "<<am<<G4endl;
529 G4double k = momentum/hbarc;
530 // G4cout<<"k = "<<k*fermi<<" 1/fermi"<<G4endl;
531 // G4cout<<"k*Bohr_radius = "<<k*Bohr_radius<<G4endl;
532 G4double ch = n/k;
533 G4double ch2 = ch*ch;
534 am *= 2.;
535 G4double xsc = ch2*twopi*(c1-c2);
536 xsc /= (1 - c1 + am)*(1 - c2 + am);
537
538 return xsc;
539}
540
541#endif
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