source: trunk/source/processes/hadronic/models/rpg/src/G4RPGKPlusInelastic.cc@ 1228

Last change on this file since 1228 was 1228, checked in by garnier, 16 years ago

update geant4.9.3 tag
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26//
27// $Id: G4RPGKPlusInelastic.cc,v 1.1 2007/07/18 21:04:20 dennis Exp $
28// GEANT4 tag $Name: geant4-09-03 $
29//
30
31#include "G4RPGKPlusInelastic.hh"
32#include "Randomize.hh"
33
34G4HadFinalState*
35G4RPGKPlusInelastic::ApplyYourself( const G4HadProjectile &aTrack,
36 G4Nucleus &targetNucleus )
37{
38 const G4HadProjectile *originalIncident = &aTrack;
39 if (originalIncident->GetKineticEnergy()<= 0.1*MeV)
40 {
41 theParticleChange.SetStatusChange(isAlive);
42 theParticleChange.SetEnergyChange(aTrack.GetKineticEnergy());
43 theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit());
44 return &theParticleChange;
45 }
46
47 // create the target particle
48
49 G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle();
50 G4ReactionProduct targetParticle( originalTarget->GetDefinition() );
51
52 if( verboseLevel > 1 )
53 {
54 const G4Material *targetMaterial = aTrack.GetMaterial();
55 G4cout << "G4RPGKPlusInelastic::ApplyYourself called" << G4endl;
56 G4cout << "kinetic energy = " << originalIncident->GetKineticEnergy() << "MeV, ";
57 G4cout << "target material = " << targetMaterial->GetName() << ", ";
58 G4cout << "target particle = " << originalTarget->GetDefinition()->GetParticleName()
59 << G4endl;
60 }
61 G4ReactionProduct currentParticle( const_cast<G4ParticleDefinition *>(originalIncident->GetDefinition()));
62 currentParticle.SetMomentum( originalIncident->Get4Momentum().vect() );
63 currentParticle.SetKineticEnergy( originalIncident->GetKineticEnergy() );
64
65 // Fermi motion and evaporation
66 // As of Geant3, the Fermi energy calculation had not been Done
67
68 G4double ek = originalIncident->GetKineticEnergy();
69 G4double amas = originalIncident->GetDefinition()->GetPDGMass();
70
71 G4double tkin = targetNucleus.Cinema( ek );
72 ek += tkin;
73 currentParticle.SetKineticEnergy( ek );
74 G4double et = ek + amas;
75 G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) );
76 G4double pp = currentParticle.GetMomentum().mag();
77 if( pp > 0.0 )
78 {
79 G4ThreeVector momentum = currentParticle.GetMomentum();
80 currentParticle.SetMomentum( momentum * (p/pp) );
81 }
82
83 // calculate black track energies
84
85 tkin = targetNucleus.EvaporationEffects( ek );
86 ek -= tkin;
87 currentParticle.SetKineticEnergy( ek );
88 et = ek + amas;
89 p = std::sqrt( std::abs((et-amas)*(et+amas)) );
90 pp = currentParticle.GetMomentum().mag();
91 if( pp > 0.0 )
92 {
93 G4ThreeVector momentum = currentParticle.GetMomentum();
94 currentParticle.SetMomentum( momentum * (p/pp) );
95 }
96
97 G4ReactionProduct modifiedOriginal = currentParticle;
98
99 currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere
100 targetParticle.SetSide( -1 ); // target always goes in backward hemisphere
101 G4bool incidentHasChanged = false;
102 G4bool targetHasChanged = false;
103 G4bool quasiElastic = false;
104 G4FastVector<G4ReactionProduct,GHADLISTSIZE> vec; // vec will contain the secondary particles
105 G4int vecLen = 0;
106 vec.Initialize( 0 );
107
108 const G4double cutOff = 0.1*MeV;
109 if( currentParticle.GetKineticEnergy() > cutOff )
110 Cascade( vec, vecLen,
111 originalIncident, currentParticle, targetParticle,
112 incidentHasChanged, targetHasChanged, quasiElastic );
113
114 CalculateMomenta( vec, vecLen,
115 originalIncident, originalTarget, modifiedOriginal,
116 targetNucleus, currentParticle, targetParticle,
117 incidentHasChanged, targetHasChanged, quasiElastic );
118
119 SetUpChange( vec, vecLen,
120 currentParticle, targetParticle,
121 incidentHasChanged );
122
123 delete originalTarget;
124
125 return &theParticleChange;
126}
127
128
129void G4RPGKPlusInelastic::Cascade(
130 G4FastVector<G4ReactionProduct,GHADLISTSIZE> &vec,
131 G4int &vecLen,
132 const G4HadProjectile *originalIncident,
133 G4ReactionProduct &currentParticle,
134 G4ReactionProduct &targetParticle,
135 G4bool &incidentHasChanged,
136 G4bool &targetHasChanged,
137 G4bool &quasiElastic )
138{
139 // Derived from H. Fesefeldt's original FORTRAN code CASKP
140 //
141 // K+ undergoes interaction with nucleon within a nucleus. Check if it is
142 // energetically possible to produce pions/kaons. In not, assume nuclear excitation
143 // occurs and input particle is degraded in energy. No other particles are produced.
144 // If reaction is possible, find the correct number of pions/protons/neutrons
145 // produced using an interpolation to multiplicity data. Replace some pions or
146 // protons/neutrons by kaons or strange baryons according to the average
147 // multiplicity per Inelastic reaction.
148 //
149 const G4double mOriginal = originalIncident->GetDefinition()->GetPDGMass();
150 const G4double etOriginal = originalIncident->GetTotalEnergy();
151 const G4double targetMass = targetParticle.GetMass();
152 G4double centerofmassEnergy = std::sqrt( mOriginal*mOriginal +
153 targetMass*targetMass +
154 2.0*targetMass*etOriginal );
155 G4double availableEnergy = centerofmassEnergy-(targetMass+mOriginal);
156 if( availableEnergy < G4PionPlus::PionPlus()->GetPDGMass() )
157 {
158 quasiElastic = true;
159 return;
160 }
161 static G4bool first = true;
162 const G4int numMul = 1200;
163 const G4int numSec = 60;
164 static G4double protmul[numMul], protnorm[numSec]; // proton constants
165 static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
166
167 // np = number of pi+, nm = number of pi-, nz = number of pi0
168
169 G4int nt=0, np=0, nm=0, nz=0;
170 const G4double c = 1.25;
171 const G4double b[] = { 0.70, 0.70 };
172 if( first ) // compute normalization constants, this will only be Done once
173 {
174 first = false;
175 G4int i;
176 for( i=0; i<numMul; ++i )protmul[i] = 0.0;
177 for( i=0; i<numSec; ++i )protnorm[i] = 0.0;
178 G4int counter = -1;
179 for( np=0; np<(numSec/3); ++np )
180 {
181 for( nm=std::max(0,np-2); nm<=np; ++nm )
182 {
183 for( nz=0; nz<numSec/3; ++nz )
184 {
185 if( ++counter < numMul )
186 {
187 nt = np+nm+nz;
188 if( nt > 0 )
189 {
190 protmul[counter] = Pmltpc(np,nm,nz,nt,b[0],c);
191 protnorm[nt-1] += protmul[counter];
192 }
193 }
194 }
195 }
196 }
197 for( i=0; i<numMul; ++i )neutmul[i] = 0.0;
198 for( i=0; i<numSec; ++i )neutnorm[i] = 0.0;
199 counter = -1;
200 for( np=0; np<numSec/3; ++np )
201 {
202 for( nm=std::max(0,np-1); nm<=(np+1); ++nm )
203 {
204 for( nz=0; nz<numSec/3; ++nz )
205 {
206 if( ++counter < numMul )
207 {
208 nt = np+nm+nz;
209 if( (nt>0) && (nt<=numSec) )
210 {
211 neutmul[counter] = Pmltpc(np,nm,nz,nt,b[1],c);
212 neutnorm[nt-1] += neutmul[counter];
213 }
214 }
215 }
216 }
217 }
218 for( i=0; i<numSec; ++i )
219 {
220 if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
221 if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
222 }
223 } // end of initialization
224
225 const G4double expxu = 82.; // upper bound for arg. of exp
226 const G4double expxl = -expxu; // lower bound for arg. of exp
227 G4ParticleDefinition *aKaonZS = G4KaonZeroShort::KaonZeroShort();
228 G4ParticleDefinition *aKaonZL = G4KaonZeroLong::KaonZeroLong();
229 G4ParticleDefinition *aNeutron = G4Neutron::Neutron();
230 G4ParticleDefinition *aProton = G4Proton::Proton();
231 G4int ieab = static_cast<G4int>(availableEnergy*5.0/GeV);
232 const G4double supp[] = {0.,0.4,0.55,0.65,0.75,0.82,0.86,0.90,0.94,0.98};
233 G4double test, w0, wp, wt, wm;
234 if( (availableEnergy < 2.0*GeV) && (G4UniformRand() >= supp[ieab]) )
235 {
236 // suppress high multiplicity events at low momentum
237 // only one pion will be produced
238
239 nm = np = nz = 0;
240 if( targetParticle.GetDefinition() == aProton )
241 {
242 test = std::exp( std::min( expxu, std::max( expxl, -sqr(1.0+b[0])/(2.0*c*c) ) ) );
243 w0 = test;
244 wp = test*2.0;
245 if( G4UniformRand() < w0/(w0+wp) )
246 nz = 1;
247 else
248 np = 1;
249 }
250 else // target is a neutron
251 {
252 test = std::exp( std::min( expxu, std::max( expxl, -sqr(1.0+b[1])/(2.0*c*c) ) ) );
253 w0 = test;
254 wp = test;
255 test = std::exp( std::min( expxu, std::max( expxl, -sqr(-1.0+b[1])/(2.0*c*c) ) ) );
256 wm = test;
257 wt = w0+wp+wm;
258 wp += w0;
259 G4double ran = G4UniformRand();
260 if( ran < w0/wt )
261 nz = 1;
262 else if( ran < wp/wt )
263 np = 1;
264 else
265 nm = 1;
266 }
267 }
268 else
269 {
270 G4double n, anpn;
271 GetNormalizationConstant( availableEnergy, n, anpn );
272 G4double ran = G4UniformRand();
273 G4double dum, excs = 0.0;
274 if( targetParticle.GetDefinition() == aProton )
275 {
276 G4int counter = -1;
277 for( np=0; (np<numSec/3) && (ran>=excs); ++np )
278 {
279 for( nm=std::max(0,np-2); (nm<=np) && (ran>=excs); ++nm )
280 {
281 for( nz=0; (nz<numSec/3) && (ran>=excs); ++nz )
282 {
283 if( ++counter < numMul )
284 {
285 nt = np+nm+nz;
286 if( nt > 0 )
287 {
288 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
289 dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
290 if( std::fabs(dum) < 1.0 )
291 {
292 if( test >= 1.0e-10 )excs += dum*test;
293 }
294 else
295 excs += dum*test;
296 }
297 }
298 }
299 }
300 }
301 if( ran >= excs )return; // 3 previous loops continued to the end
302 np--; nm--; nz--;
303 }
304 else // target must be a neutron
305 {
306 G4int counter = -1;
307 for( np=0; (np<numSec/3) && (ran>=excs); ++np )
308 {
309 for( nm=std::max(0,np-1); (nm<=(np+1)) && (ran>=excs); ++nm )
310 {
311 for( nz=0; (nz<numSec/3) && (ran>=excs); ++nz )
312 {
313 if( ++counter < numMul )
314 {
315 nt = np+nm+nz;
316 if( (nt>=1) && (nt<=numSec) )
317 {
318 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
319 dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
320 if( std::fabs(dum) < 1.0 )
321 {
322 if( test >= 1.0e-10 )excs += dum*test;
323 }
324 else
325 excs += dum*test;
326 }
327 }
328 }
329 }
330 }
331 if( ran >= excs )return; // 3 previous loops continued to the end
332 np--; nm--; nz--;
333 }
334 }
335
336 if( targetParticle.GetDefinition() == aProton )
337 {
338 switch( np-nm )
339 {
340 case 1:
341 if( G4UniformRand() < 0.5 )
342 {
343 if( G4UniformRand() < 0.5 )
344 currentParticle.SetDefinitionAndUpdateE( aKaonZS );
345 else
346 currentParticle.SetDefinitionAndUpdateE( aKaonZL );
347 incidentHasChanged = true;
348 }
349 else
350 {
351 targetParticle.SetDefinitionAndUpdateE( aNeutron );
352 targetHasChanged = true;
353 }
354 break;
355 case 2:
356 if( G4UniformRand() < 0.5 )
357 currentParticle.SetDefinitionAndUpdateE( aKaonZS );
358 else
359 currentParticle.SetDefinitionAndUpdateE( aKaonZL );
360 incidentHasChanged = true;
361 targetParticle.SetDefinitionAndUpdateE( aNeutron );
362 incidentHasChanged = true;
363 targetHasChanged = true;
364 break;
365 default:
366 break;
367 }
368 }
369 else // target is a neutron
370 {
371 switch( np-nm )
372 {
373 case 0:
374 if( G4UniformRand() < 0.25 )
375 {
376 if( G4UniformRand() < 0.5 )
377 currentParticle.SetDefinitionAndUpdateE( aKaonZS );
378 else
379 currentParticle.SetDefinitionAndUpdateE( aKaonZL );
380 targetParticle.SetDefinitionAndUpdateE( aProton );
381 incidentHasChanged = true;
382 targetHasChanged = true;
383 }
384 break;
385 case 1:
386 if( G4UniformRand() < 0.5 )
387 currentParticle.SetDefinitionAndUpdateE( aKaonZS );
388 else
389 currentParticle.SetDefinitionAndUpdateE( aKaonZL );
390 incidentHasChanged = true;
391 break;
392 default: // assumes nm = np+1 so charge is conserved
393 targetParticle.SetDefinitionAndUpdateE( aProton );
394 targetHasChanged = true;
395 break;
396 }
397 }
398 SetUpPions( np, nm, nz, vec, vecLen );
399 return;
400}
401
402 /* end of file */
403
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