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G4LEAntiSigmaPlusInelastic.cc @ 1340

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27	// $Id: G4LEAntiSigmaPlusInelastic.cc,v 1.11 2006/06/29 20:44:51 gunter Exp $
28	// GEANT4 tag $Name: geant4-09-03-ref-09 $
29	//
30	// Hadronic Process: AntiSigmaPlus Inelastic Process
31	// J.L. Chuma, TRIUMF, 19-Feb-1997
32	// Last modified: 27-Mar-1997
33	// Modified by J.L.Chuma 30-Apr-97: added originalTarget for CalculateMomenta
34
35	#include "G4LEAntiSigmaPlusInelastic.hh"
36	#include "Randomize.hh"
37
38	G4HadFinalState *
39	G4LEAntiSigmaPlusInelastic::ApplyYourself( const G4HadProjectile &aTrack,
40	G4Nucleus &targetNucleus )
41	{
42	const G4HadProjectile *originalIncident = &aTrack;
43	if (originalIncident->GetKineticEnergy()<= 0.1*MeV)
44	{
45	theParticleChange.SetStatusChange(isAlive);
46	theParticleChange.SetEnergyChange(aTrack.GetKineticEnergy());
47	theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit());
48	return &theParticleChange;
49	}
50	//
51	// create the target particle
52	//
53	G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle();
54
55	if( verboseLevel > 1 )
56	{
57	const G4Material *targetMaterial = aTrack.GetMaterial();
58	G4cout << "G4LEAntiSigmaPlusInelastic::ApplyYourself called" << G4endl;
59	G4cout << "kinetic energy = " << originalIncident->GetKineticEnergy()/MeV << "MeV, ";
60	G4cout << "target material = " << targetMaterial->GetName() << ", ";
61	G4cout << "target particle = " << originalTarget->GetDefinition()->GetParticleName()
62	<< G4endl;
63	}
64	//
65	// Fermi motion and evaporation
66	// As of Geant3, the Fermi energy calculation had not been Done
67	//
68	G4double ek = originalIncident->GetKineticEnergy()/MeV;
69	G4double amas = originalIncident->GetDefinition()->GetPDGMass()/MeV;
70	G4ReactionProduct modifiedOriginal;
71	modifiedOriginal = *originalIncident;
72
73	G4double tkin = targetNucleus.Cinema( ek );
74	ek += tkin;
75	modifiedOriginal.SetKineticEnergy( ek*MeV );
76	G4double et = ek + amas;
77	G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) );
78	G4double pp = modifiedOriginal.GetMomentum().mag()/MeV;
79	if( pp > 0.0 )
80	{
81	G4ThreeVector momentum = modifiedOriginal.GetMomentum();
82	modifiedOriginal.SetMomentum( momentum * (p/pp) );
83	}
84	//
85	// calculate black track energies
86	//
87	tkin = targetNucleus.EvaporationEffects( ek );
88	ek -= tkin;
89	modifiedOriginal.SetKineticEnergy( ek*MeV );
90	et = ek + amas;
91	p = std::sqrt( std::abs((et-amas)*(et+amas)) );
92	pp = modifiedOriginal.GetMomentum().mag()/MeV;
93	if( pp > 0.0 )
94	{
95	G4ThreeVector momentum = modifiedOriginal.GetMomentum();
96	modifiedOriginal.SetMomentum( momentum * (p/pp) );
97	}
98	G4ReactionProduct currentParticle = modifiedOriginal;
99	G4ReactionProduct targetParticle;
100	targetParticle = *originalTarget;
101	currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere
102	targetParticle.SetSide( -1 ); // target always goes in backward hemisphere
103	G4bool incidentHasChanged = false;
104	G4bool targetHasChanged = false;
105	G4bool quasiElastic = false;
106	G4FastVector<G4ReactionProduct,GHADLISTSIZE> vec; // vec will contain the secondary particles
107	G4int vecLen = 0;
108	vec.Initialize( 0 );
109
110	const G4double cutOff = 0.1;
111	const G4double anni = std::min( 1.3*currentParticle.GetTotalMomentum()/GeV, 0.4 );
112	if( (currentParticle.GetKineticEnergy()/MeV > cutOff) \|\| (G4UniformRand() > anni) )
113	Cascade( vec, vecLen,
114	originalIncident, currentParticle, targetParticle,
115	incidentHasChanged, targetHasChanged, quasiElastic );
116
117	CalculateMomenta( vec, vecLen,
118	originalIncident, originalTarget, modifiedOriginal,
119	targetNucleus, currentParticle, targetParticle,
120	incidentHasChanged, targetHasChanged, quasiElastic );
121
122	SetUpChange( vec, vecLen,
123	currentParticle, targetParticle,
124	incidentHasChanged );
125
126	delete originalTarget;
127	return &theParticleChange;
128	}
129
130	void
131	G4LEAntiSigmaPlusInelastic::Cascade(
132	G4FastVector<G4ReactionProduct,GHADLISTSIZE> &vec,
133	G4int& vecLen,
134	const G4HadProjectile *originalIncident,
135	G4ReactionProduct &currentParticle,
136	G4ReactionProduct &targetParticle,
137	G4bool &incidentHasChanged,
138	G4bool &targetHasChanged,
139	G4bool &quasiElastic )
140	{
141	// derived from original FORTRAN code CASASP by H. Fesefeldt (13-Sep-1987)
142	//
143	// AntiSigmaPlus undergoes interaction with nucleon within a nucleus. Check if it is
144	// energetically possible to produce pions/kaons. In not, assume nuclear excitation
145	// occurs and input particle is degraded in energy. No other particles are produced.
146	// If reaction is possible, find the correct number of pions/protons/neutrons
147	// produced using an interpolation to multiplicity data. Replace some pions or
148	// protons/neutrons by kaons or strange baryons according to the average
149	// multiplicity per Inelastic reaction.
150	//
151	const G4double mOriginal = originalIncident->GetDefinition()->GetPDGMass()/MeV;
152	const G4double etOriginal = originalIncident->GetTotalEnergy()/MeV;
153	const G4double pOriginal = originalIncident->GetTotalMomentum()/MeV;
154	const G4double targetMass = targetParticle.GetMass()/MeV;
155	G4double centerofmassEnergy = std::sqrt( mOriginal*mOriginal +
156	targetMass*targetMass +
157	2.0targetMassetOriginal );
158	G4double availableEnergy = centerofmassEnergy-(targetMass+mOriginal);
159
160	static G4bool first = true;
161	const G4int numMul = 1200;
162	const G4int numMulA = 400;
163	const G4int numSec = 60;
164	static G4double protmul[numMul], protnorm[numSec]; // proton constants
165	static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
166	static G4double protmulA[numMulA], protnormA[numSec]; // proton constants
167	static G4double neutmulA[numMulA], neutnormA[numSec]; // neutron constants
168	// np = number of pi+, nm = number of pi-, nz = number of pi0
169	G4int counter, nt=0, np=0, nm=0, nz=0;
170	G4double test;
171	const G4double c = 1.25;
172	const G4double b[] = { 0.7, 0.7 };
173	if( first ) // compute normalization constants, this will only be Done once
174	{
175	first = false;
176	G4int i;
177	for( i=0; i<numMul; ++i )protmul[i] = 0.0;
178	for( i=0; i<numSec; ++i )protnorm[i] = 0.0;
179	counter = -1;
180	for( np=0; np<(numSec/3); ++np )
181	{
182	for( nm=std::max(0,np-1); nm<=(np+1); ++nm )
183	{
184	for( nz=0; nz<numSec/3; ++nz )
185	{
186	if( ++counter < numMul )
187	{
188	nt = np+nm+nz;
189	if( nt>0 && nt<=numSec )
190	{
191	protmul[counter] = Pmltpc(np,nm,nz,nt,b[0],c);
192	protnorm[nt-1] += protmul[counter];
193	}
194	}
195	}
196	}
197	}
198	for( i=0; i<numMul; ++i )neutmul[i] = 0.0;
199	for( i=0; i<numSec; ++i )neutnorm[i] = 0.0;
200	counter = -1;
201	for( np=0; np<numSec/3; ++np )
202	{
203	for( nm=np; nm<=(np+2); ++nm )
204	{
205	for( nz=0; nz<numSec/3; ++nz )
206	{
207	if( ++counter < numMul )
208	{
209	nt = np+nm+nz;
210	if( nt>0 && nt<=numSec )
211	{
212	neutmul[counter] = Pmltpc(np,nm,nz,nt,b[1],c);
213	neutnorm[nt-1] += neutmul[counter];
214	}
215	}
216	}
217	}
218	}
219	for( i=0; i<numSec; ++i )
220	{
221	if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
222	if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
223	}
224	//
225	// do the same for annihilation channels
226	//
227	for( i=0; i<numMulA; ++i )protmulA[i] = 0.0;
228	for( i=0; i<numSec; ++i )protnormA[i] = 0.0;
229	counter = -1;
230	for( np=1; np<(numSec/3); ++np )
231	{
232	nm = np;
233	for( nz=0; nz<numSec/3; ++nz )
234	{
235	if( ++counter < numMulA )
236	{
237	nt = np+nm+nz;
238	if( nt>1 && nt<=numSec )
239	{
240	protmulA[counter] = Pmltpc(np,nm,nz,nt,b[0],c);
241	protnormA[nt-1] += protmulA[counter];
242	}
243	}
244	}
245	}
246	for( i=0; i<numMulA; ++i )neutmulA[i] = 0.0;
247	for( i=0; i<numSec; ++i )neutnormA[i] = 0.0;
248	counter = -1;
249	for( np=0; np<numSec/3; ++np )
250	{
251	nm = np+1;
252	for( nz=0; nz<numSec/3; ++nz )
253	{
254	if( ++counter < numMulA )
255	{
256	nt = np+nm+nz;
257	if( nt>1 && nt<=numSec )
258	{
259	neutmulA[counter] = Pmltpc(np,nm,nz,nt,b[1],c);
260	neutnormA[nt-1] += neutmulA[counter];
261	}
262	}
263	}
264	}
265	for( i=0; i<numSec; ++i )
266	{
267	if( protnormA[i] > 0.0 )protnormA[i] = 1.0/protnormA[i];
268	if( neutnormA[i] > 0.0 )neutnormA[i] = 1.0/neutnormA[i];
269	}
270	} // end of initialization
271
272	const G4double expxu = 82.; // upper bound for arg. of exp
273	const G4double expxl = -expxu; // lower bound for arg. of exp
274	G4ParticleDefinition *aNeutron = G4Neutron::Neutron();
275	G4ParticleDefinition *aProton = G4Proton::Proton();
276	G4ParticleDefinition *aPiPlus = G4PionPlus::PionPlus();
277	G4ParticleDefinition *anAntiLambda = G4AntiLambda::AntiLambda();
278	G4ParticleDefinition *aKaonMinus = G4KaonMinus::KaonMinus();
279	G4ParticleDefinition *aKaonPlus = G4KaonPlus::KaonPlus();
280	G4ParticleDefinition *aKaonZL = G4KaonZeroLong::KaonZeroLong();
281	G4ParticleDefinition *anAntiSigmaZero = G4AntiSigmaZero::AntiSigmaZero();
282	const G4double anhl[] = {1.00,1.00,1.00,1.00,1.00,1.00,1.00,1.00,0.97,0.88,
283	0.85,0.81,0.75,0.64,0.64,0.55,0.55,0.45,0.47,0.40,
284	0.39,0.36,0.33,0.10,0.01};
285	G4int iplab = G4int( pOriginal/GeV*10.0 );
286	if( iplab > 9 )iplab = G4int( (pOriginal/GeV- 1.0)*5.0 ) + 10;
287	if( iplab > 14 )iplab = G4int( pOriginal/GeV- 2.0 ) + 15;
288	if( iplab > 22 )iplab = G4int( (pOriginal/GeV-10.0)/10.0 ) + 23;
289	if( iplab > 24 )iplab = 24;
290	if( G4UniformRand() > anhl[iplab] )
291	{
292	if( availableEnergy <= aPiPlus->GetPDGMass()/MeV )
293	{
294	quasiElastic = true;
295	return;
296	}
297	G4double n, anpn;
298	GetNormalizationConstant( availableEnergy, n, anpn );
299	G4double ran = G4UniformRand();
300	G4double dum, excs = 0.0;
301	if( targetParticle.GetDefinition() == aProton )
302	{
303	counter = -1;
304	for( np=0; np<numSec/3 && ran>=excs; ++np )
305	{
306	for( nm=std::max(0,np-1); nm<=(np+1) && ran>=excs; ++nm )
307	{
308	for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
309	{
310	if( ++counter < numMul )
311	{
312	nt = np+nm+nz;
313	if( (nt>0) && (nt<=numSec) )
314	{
315	test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)(ntnt)/(n*n) ) ) );
316	dum = (pi/anpn)ntprotmul[counter]protnorm[nt-1]/(2.0n*n);
317	if( std::fabs(dum) < 1.0 )
318	{
319	if( test >= 1.0e-10 )excs += dum*test;
320	}
321	else
322	excs += dum*test;
323	}
324	}
325	}
326	}
327	}
328	if( ran >= excs ) // 3 previous loops continued to the end
329	{
330	quasiElastic = true;
331	return;
332	}
333	np--; nm--; nz--;
334	G4int ncht = std::min( 3, std::max( 1, np-nm+2 ) );
335	switch( ncht )
336	{
337	case 1:
338	if( G4UniformRand() < 0.5 )
339	currentParticle.SetDefinitionAndUpdateE( anAntiLambda );
340	else
341	currentParticle.SetDefinitionAndUpdateE( anAntiSigmaZero );
342	incidentHasChanged = true;
343	break;
344	case 2:
345	if( G4UniformRand() >= 0.5 )
346	{
347	if( G4UniformRand() < 0.5 )
348	currentParticle.SetDefinitionAndUpdateE( anAntiLambda );
349	else
350	currentParticle.SetDefinitionAndUpdateE( anAntiSigmaZero );
351	incidentHasChanged = true;
352	}
353	targetParticle.SetDefinitionAndUpdateE( aNeutron );
354	targetHasChanged = true;
355	break;
356	case 3:
357	targetParticle.SetDefinitionAndUpdateE( aNeutron );
358	targetHasChanged = true;
359	break;
360	}
361	}
362	else // target must be a neutron
363	{
364	counter = -1;
365	for( np=0; np<numSec/3 && ran>=excs; ++np )
366	{
367	for( nm=np; nm<=(np+2) && ran>=excs; ++nm )
368	{
369	for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
370	{
371	if( ++counter < numMul )
372	{
373	nt = np+nm+nz;
374	if( (nt>0) && (nt<=numSec) )
375	{
376	test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)(ntnt)/(n*n) ) ) );
377	dum = (pi/anpn)ntneutmul[counter]neutnorm[nt-1]/(2.0n*n);
378	if( std::fabs(dum) < 1.0 )
379	{
380	if( test >= 1.0e-10 )excs += dum*test;
381	}
382	else
383	excs += dum*test;
384	}
385	}
386	}
387	}
388	}
389	if( ran >= excs ) // 3 previous loops continued to the end
390	{
391	quasiElastic = true;
392	return;
393	}
394	np--; nm--; nz--;
395	G4int ncht = std::min( 3, std::max( 1, np-nm+3 ) );
396	switch( ncht )
397	{
398	case 1:
399	if( G4UniformRand() < 0.5 )
400	currentParticle.SetDefinitionAndUpdateE( anAntiLambda );
401	else
402	currentParticle.SetDefinitionAndUpdateE( anAntiSigmaZero );
403	incidentHasChanged = true;
404	targetParticle.SetDefinitionAndUpdateE( aProton );
405	targetHasChanged = true;
406	break;
407	case 2:
408	if( G4UniformRand() < 0.5 )
409	{
410	if( G4UniformRand() < 0.5 )
411	{
412	currentParticle.SetDefinitionAndUpdateE( anAntiLambda );
413	incidentHasChanged = true;
414	}
415	else
416	{
417	targetParticle.SetDefinitionAndUpdateE( aProton );
418	targetHasChanged = true;
419	}
420	}
421	else
422	{
423	if( G4UniformRand() < 0.5 )
424	{
425	currentParticle.SetDefinitionAndUpdateE( anAntiSigmaZero );
426	incidentHasChanged = true;
427	}
428	else
429	{
430	targetParticle.SetDefinitionAndUpdateE( aProton );
431	targetHasChanged = true;
432	}
433	}
434	break;
435	case 3:
436	break;
437	}
438	}
439	}
440	else // random number <= anhl[iplab]
441	{
442	if( centerofmassEnergy <= aPiPlus->GetPDGMass()/MeV+aKaonPlus->GetPDGMass()/MeV )
443	{
444	quasiElastic = true;
445	return;
446	}
447	G4double n, anpn;
448	GetNormalizationConstant( -centerofmassEnergy, n, anpn );
449	G4double ran = G4UniformRand();
450	G4double dum, excs = 0.0;
451	if( targetParticle.GetDefinition() == aProton )
452	{
453	counter = -1;
454	for( np=1; np<numSec/3 && ran>=excs; ++np )
455	{
456	nm = np;
457	for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
458	{
459	if( ++counter < numMulA )
460	{
461	nt = np+nm+nz;
462	if( nt>1 && nt<=numSec )
463	{
464	test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)(ntnt)/(n*n) ) ) );
465	dum = (pi/anpn)ntprotmulA[counter]protnormA[nt-1]/(2.0n*n);
466	if( std::fabs(dum) < 1.0 )
467	{
468	if( test >= 1.0e-10 )excs += dum*test;
469	}
470	else
471	excs += dum*test;
472	}
473	}
474	}
475	}
476	if( ran >= excs ) // 3 previous loops continued to the end
477	{
478	quasiElastic = true;
479	return;
480	}
481	np--; nz--;
482	}
483	else // target must be a neutron
484	{
485	counter = -1;
486	for( np=0; np<numSec/3 && ran>=excs; ++np )
487	{
488	nm = np+1;
489	for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
490	{
491	if( ++counter < numMulA )
492	{
493	nt = np+nm+nz;
494	if( nt>1 && nt<=numSec )
495	{
496	test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)(ntnt)/(n*n) ) ) );
497	dum = (pi/anpn)ntneutmulA[counter]neutnormA[nt-1]/(2.0n*n);
498	if( std::fabs(dum) < 1.0 )
499	{
500	if( test >= 1.0e-10 )excs += dum*test;
501	}
502	else
503	excs += dum*test;
504	}
505	}
506	}
507	}
508	if( ran >= excs ) // 3 previous loops continued to the end
509	{
510	quasiElastic = true;
511	return;
512	}
513	np--; nz--;
514	}
515	if( nz > 0 )
516	{
517	if( nm > 0 )
518	{
519	if( G4UniformRand() < 0.5 )
520	{
521	vec.Initialize( 1 );
522	G4ReactionProduct *p= new G4ReactionProduct;
523	p->SetDefinition( aKaonMinus );
524	(G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
525	vec.SetElement( vecLen++, p );
526	--nm;
527	}
528	else
529	{
530	vec.Initialize( 1 );
531	G4ReactionProduct *p= new G4ReactionProduct ;
532	p->SetDefinition( aKaonZL );
533	(G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
534	vec.SetElement( vecLen++, p );
535	--nz;
536	}
537	}
538	else // nm == 0
539	{
540	vec.Initialize( 1 );
541	G4ReactionProduct *p = new G4ReactionProduct;
542	p->SetDefinition( aKaonZL );
543	(G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
544	vec.SetElement( vecLen++, p );
545	--nz;
546	}
547	}
548	else // nz == 0
549	{
550	if( nm > 0 )
551	{
552	vec.Initialize( 1 );
553	G4ReactionProduct *p = new G4ReactionProduct;
554	p->SetDefinition( aKaonMinus );
555	(G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
556	vec.SetElement( vecLen++, p );
557	--nm;
558	}
559	}
560	currentParticle.SetMass( 0.0 );
561	targetParticle.SetMass( 0.0 );
562	}
563	SetUpPions( np, nm, nz, vec, vecLen );
564	return;
565	}
566
567	/* end of file */
568

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