source: trunk/source/processes/hadronic/models/rpg/src/G4RPGSigmaPlusInelastic.cc@ 1199

Last change on this file since 1199 was 1196, checked in by garnier, 16 years ago

update CVS release candidate geant4.9.3.01
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25//
26// $Id: G4RPGSigmaPlusInelastic.cc,v 1.1 2007/07/18 21:04:21 dennis Exp $
27// GEANT4 tag $Name: geant4-09-03-cand-01 $
28//
29
30#include "G4RPGSigmaPlusInelastic.hh"
31#include "Randomize.hh"
32
33G4HadFinalState*
34G4RPGSigmaPlusInelastic::ApplyYourself( const G4HadProjectile &aTrack,
35 G4Nucleus &targetNucleus )
36{
37 const G4HadProjectile *originalIncident = &aTrack;
38 if (originalIncident->GetKineticEnergy()<= 0.1*MeV)
39 {
40 theParticleChange.SetStatusChange(isAlive);
41 theParticleChange.SetEnergyChange(aTrack.GetKineticEnergy());
42 theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit());
43 return &theParticleChange;
44 }
45
46 // create the target particle
47
48 G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle();
49
50 if( verboseLevel > 1 )
51 {
52 const G4Material *targetMaterial = aTrack.GetMaterial();
53 G4cout << "G4RPGSigmaPlusInelastic::ApplyYourself called" << G4endl;
54 G4cout << "kinetic energy = " << originalIncident->GetKineticEnergy()/MeV << "MeV, ";
55 G4cout << "target material = " << targetMaterial->GetName() << ", ";
56 G4cout << "target particle = " << originalTarget->GetDefinition()->GetParticleName()
57 << G4endl;
58 }
59
60 // Fermi motion and evaporation
61 // As of Geant3, the Fermi energy calculation had not been Done
62
63 G4double ek = originalIncident->GetKineticEnergy()/MeV;
64 G4double amas = originalIncident->GetDefinition()->GetPDGMass()/MeV;
65 G4ReactionProduct modifiedOriginal;
66 modifiedOriginal = *originalIncident;
67
68 G4double tkin = targetNucleus.Cinema( ek );
69 ek += tkin;
70 modifiedOriginal.SetKineticEnergy( ek*MeV );
71 G4double et = ek + amas;
72 G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) );
73 G4double pp = modifiedOriginal.GetMomentum().mag()/MeV;
74 if( pp > 0.0 )
75 {
76 G4ThreeVector momentum = modifiedOriginal.GetMomentum();
77 modifiedOriginal.SetMomentum( momentum * (p/pp) );
78 }
79 //
80 // calculate black track energies
81 //
82 tkin = targetNucleus.EvaporationEffects( ek );
83 ek -= tkin;
84 modifiedOriginal.SetKineticEnergy( ek*MeV );
85 et = ek + amas;
86 p = std::sqrt( std::abs((et-amas)*(et+amas)) );
87 pp = modifiedOriginal.GetMomentum().mag()/MeV;
88 if( pp > 0.0 )
89 {
90 G4ThreeVector momentum = modifiedOriginal.GetMomentum();
91 modifiedOriginal.SetMomentum( momentum * (p/pp) );
92 }
93 G4ReactionProduct currentParticle = modifiedOriginal;
94 G4ReactionProduct targetParticle;
95 targetParticle = *originalTarget;
96 currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere
97 targetParticle.SetSide( -1 ); // target always goes in backward hemisphere
98 G4bool incidentHasChanged = false;
99 G4bool targetHasChanged = false;
100 G4bool quasiElastic = false;
101 G4FastVector<G4ReactionProduct,GHADLISTSIZE> vec; // vec will contain the secondary particles
102 G4int vecLen = 0;
103 vec.Initialize( 0 );
104
105 const G4double cutOff = 0.1;
106 if( currentParticle.GetKineticEnergy()/MeV > cutOff )
107 Cascade( vec, vecLen,
108 originalIncident, currentParticle, targetParticle,
109 incidentHasChanged, targetHasChanged, quasiElastic );
110
111 CalculateMomenta( vec, vecLen,
112 originalIncident, originalTarget, modifiedOriginal,
113 targetNucleus, currentParticle, targetParticle,
114 incidentHasChanged, targetHasChanged, quasiElastic );
115
116 SetUpChange( vec, vecLen,
117 currentParticle, targetParticle,
118 incidentHasChanged );
119
120 delete originalTarget;
121 return &theParticleChange;
122}
123
124void G4RPGSigmaPlusInelastic::Cascade(
125 G4FastVector<G4ReactionProduct,GHADLISTSIZE> &vec,
126 G4int& vecLen,
127 const G4HadProjectile *originalIncident,
128 G4ReactionProduct &currentParticle,
129 G4ReactionProduct &targetParticle,
130 G4bool &incidentHasChanged,
131 G4bool &targetHasChanged,
132 G4bool &quasiElastic )
133{
134 // Derived from H. Fesefeldt's original FORTRAN code CASSP
135 //
136 // SigmaPlus undergoes interaction with nucleon within a nucleus. Check if it is
137 // energetically possible to produce pions/kaons. In not, assume nuclear excitation
138 // occurs and input particle is degraded in energy. No other particles are produced.
139 // If reaction is possible, find the correct number of pions/protons/neutrons
140 // produced using an interpolation to multiplicity data. Replace some pions or
141 // protons/neutrons by kaons or strange baryons according to the average
142 // multiplicity per inelastic reaction.
143
144 const G4double mOriginal = originalIncident->GetDefinition()->GetPDGMass()/MeV;
145 const G4double etOriginal = originalIncident->GetTotalEnergy()/MeV;
146 const G4double targetMass = targetParticle.GetMass()/MeV;
147 G4double centerofmassEnergy = std::sqrt( mOriginal*mOriginal +
148 targetMass*targetMass +
149 2.0*targetMass*etOriginal );
150 G4double availableEnergy = centerofmassEnergy-(targetMass+mOriginal);
151 if( availableEnergy <= G4PionPlus::PionPlus()->GetPDGMass()/MeV )
152 {
153 quasiElastic = true;
154 return;
155 }
156 static G4bool first = true;
157 const G4int numMul = 1200;
158 const G4int numSec = 60;
159 static G4double protmul[numMul], protnorm[numSec]; // proton constants
160 static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
161 // np = number of pi+, nm = number of pi-, nz = number of pi0
162 G4int counter, nt=0, np=0, nm=0, nz=0;
163 G4double test;
164 const G4double c = 1.25;
165 const G4double b[] = { 0.7, 0.7 };
166 if( first ) // compute normalization constants, this will only be Done once
167 {
168 first = false;
169 G4int i;
170 for( i=0; i<numMul; ++i )protmul[i] = 0.0;
171 for( i=0; i<numSec; ++i )protnorm[i] = 0.0;
172 counter = -1;
173 for( np=0; np<(numSec/3); ++np )
174 {
175 for( nm=np; nm<=(np+2); ++nm )
176 {
177 for( nz=0; nz<numSec/3; ++nz )
178 {
179 if( ++counter < numMul )
180 {
181 nt = np+nm+nz;
182 if( nt>0 && nt<=numSec )
183 {
184 protmul[counter] = Pmltpc(np,nm,nz,nt,b[0],c);
185 protnorm[nt-1] += protmul[counter];
186 }
187 }
188 }
189 }
190 }
191 for( i=0; i<numMul; ++i )neutmul[i] = 0.0;
192 for( i=0; i<numSec; ++i )neutnorm[i] = 0.0;
193 counter = -1;
194 for( np=0; np<numSec/3; ++np )
195 {
196 for( nm=std::max(0,np-1); nm<=(np+1); ++nm )
197 {
198 for( nz=0; nz<numSec/3; ++nz )
199 {
200 if( ++counter < numMul )
201 {
202 nt = np+nm+nz;
203 if( nt>0 && nt<=numSec )
204 {
205 neutmul[counter] = Pmltpc(np,nm,nz,nt,b[1],c);
206 neutnorm[nt-1] += neutmul[counter];
207 }
208 }
209 }
210 }
211 }
212 for( i=0; i<numSec; ++i )
213 {
214 if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
215 if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
216 }
217 } // end of initialization
218
219 const G4double expxu = 82.; // upper bound for arg. of exp
220 const G4double expxl = -expxu; // lower bound for arg. of exp
221 G4ParticleDefinition *aNeutron = G4Neutron::Neutron();
222 G4ParticleDefinition *aProton = G4Proton::Proton();
223 G4ParticleDefinition *aLambda = G4Lambda::Lambda();
224 G4ParticleDefinition *aSigmaZero = G4SigmaZero::SigmaZero();
225 //
226 // energetically possible to produce pion(s) --> inelastic scattering
227 //
228 G4double n, anpn;
229 GetNormalizationConstant( availableEnergy, n, anpn );
230 G4double ran = G4UniformRand();
231 G4double dum, excs = 0.0;
232 if( targetParticle.GetDefinition() == aProton )
233 {
234 counter = -1;
235 for( np=0; np<numSec/3 && ran>=excs; ++np )
236 {
237 for( nm=np; nm<=(np+2) && ran>=excs; ++nm )
238 {
239 for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
240 {
241 if( ++counter < numMul )
242 {
243 nt = np+nm+nz;
244 if( nt>0 && nt<=numSec )
245 {
246 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
247 dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
248 if( std::fabs(dum) < 1.0 )
249 {
250 if( test >= 1.0e-10 )excs += dum*test;
251 }
252 else
253 excs += dum*test;
254 }
255 }
256 }
257 }
258 }
259 if( ran >= excs ) // 3 previous loops continued to the end
260 {
261 quasiElastic = true;
262 return;
263 }
264 np--; nm--; nz--;
265 switch( std::min( 3, std::max( 1, np-nm+3 ) ) )
266 {
267 case 1:
268 if( G4UniformRand() < 0.5 )
269 currentParticle.SetDefinitionAndUpdateE( aLambda );
270 else
271 currentParticle.SetDefinitionAndUpdateE( aSigmaZero );
272 incidentHasChanged = true;
273 targetParticle.SetDefinitionAndUpdateE( aNeutron );
274 targetHasChanged = true;
275 break;
276 case 2:
277 if( G4UniformRand() < 0.5 )
278 {
279 targetParticle.SetDefinitionAndUpdateE( aNeutron );
280 targetHasChanged = true;
281 }
282 else
283 {
284 if( G4UniformRand() < 0.5 )
285 currentParticle.SetDefinitionAndUpdateE( aLambda );
286 else
287 currentParticle.SetDefinitionAndUpdateE( aSigmaZero );
288 incidentHasChanged = true;
289 }
290 break;
291 case 3:
292 break;
293 }
294 }
295 else // target must be a neutron
296 {
297 counter = -1;
298 for( np=0; np<numSec/3 && ran>=excs; ++np )
299 {
300 for( nm=std::max(0,np-1); nm<=(np+1) && ran>=excs; ++nm )
301 {
302 for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
303 {
304 if( ++counter < numMul )
305 {
306 nt = np+nm+nz;
307 if( nt>0 && nt<=numSec )
308 {
309 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
310 dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
311 if( std::fabs(dum) < 1.0 )
312 {
313 if( test >= 1.0e-10 )excs += dum*test;
314 }
315 else
316 excs += dum*test;
317 }
318 }
319 }
320 }
321 }
322 if( ran >= excs ) // 3 previous loops continued to the end
323 {
324 quasiElastic = true;
325 return;
326 }
327 np--; nm--; nz--;
328 switch( std::min( 3, std::max( 1, np-nm+2 ) ) )
329 {
330 case 1:
331 targetParticle.SetDefinitionAndUpdateE( aProton );
332 targetHasChanged = true;
333 break;
334 case 2:
335 if( G4UniformRand() < 0.5 )
336 {
337 if( G4UniformRand() < 0.5 )
338 {
339 currentParticle.SetDefinitionAndUpdateE( aLambda );
340 incidentHasChanged = true;
341 targetParticle.SetDefinitionAndUpdateE( aProton );
342 targetHasChanged = true;
343 }
344 else
345 {
346 targetParticle.SetDefinitionAndUpdateE( aNeutron );
347 targetHasChanged = true;
348 }
349 }
350 else
351 {
352 if( G4UniformRand() < 0.5 )
353 {
354 currentParticle.SetDefinitionAndUpdateE( aSigmaZero );
355 incidentHasChanged = true;
356 targetParticle.SetDefinitionAndUpdateE( aProton );
357 targetHasChanged = true;
358 }
359 }
360 break;
361 case 3:
362 if( G4UniformRand() < 0.5 )
363 currentParticle.SetDefinitionAndUpdateE( aLambda );
364 else
365 currentParticle.SetDefinitionAndUpdateE( aSigmaZero );
366 incidentHasChanged = true;
367 break;
368 }
369 }
370 SetUpPions( np, nm, nz, vec, vecLen );
371 return;
372}
373
374 /* end of file */
375
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