source: trunk/source/processes/hadronic/models/low_energy/src/G4LEKaonZeroInelastic.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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27// $Id: G4LEKaonZeroInelastic.cc,v 1.9 2006/06/29 20:45:03 gunter Exp $
28// GEANT4 tag $Name: geant4-09-02 $
29//
30 // Hadronic Process: Low Energy KaonZeroShort Inelastic Process
31 // J.L. Chuma, TRIUMF, 11-Feb-1997
32 // Last modified: 27-Mar-1997
33 // Modified by J.L.Chuma 30-Apr-97: added originalTarget for CalculateMomenta
34
35#include "G4LEKaonZeroInelastic.hh"
36#include "Randomize.hh"
37
38 G4HadFinalState *
39 G4LEKaonZeroInelastic::ApplyYourself( const G4HadProjectile &aTrack,
40 G4Nucleus &targetNucleus )
41 {
42 const G4HadProjectile *originalIncident = &aTrack;
43 //
44 // create the target particle
45 //
46 G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle();
47
48 if( verboseLevel > 1 )
49 {
50 const G4Material *targetMaterial = aTrack.GetMaterial();
51 G4cout << "G4LEKaonZeroInelastic::ApplyYourself called" << G4endl;
52 G4cout << "kinetic energy = " << originalIncident->GetKineticEnergy()/MeV << "MeV, ";
53 G4cout << "target material = " << targetMaterial->GetName() << ", ";
54 G4cout << "target particle = " << originalTarget->GetDefinition()->GetParticleName()
55 << G4endl;
56 }
57 //
58 // Fermi motion and evaporation
59 // As of Geant3, the Fermi energy calculation had not been Done
60 //
61 G4double ek = originalIncident->GetKineticEnergy()/MeV;
62 G4double amas = originalIncident->GetDefinition()->GetPDGMass()/MeV;
63 G4ReactionProduct modifiedOriginal;
64 modifiedOriginal = *originalIncident;
65
66 G4double tkin = targetNucleus.Cinema( ek );
67 ek += tkin;
68 modifiedOriginal.SetKineticEnergy( ek*MeV );
69 G4double et = ek + amas;
70 G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) );
71 G4double pp = modifiedOriginal.GetMomentum().mag()/MeV;
72 if( pp > 0.0 )
73 {
74 G4ThreeVector momentum = modifiedOriginal.GetMomentum();
75 modifiedOriginal.SetMomentum( momentum * (p/pp) );
76 }
77 //
78 // calculate black track energies
79 //
80 tkin = targetNucleus.EvaporationEffects( ek );
81 ek -= tkin;
82 modifiedOriginal.SetKineticEnergy( ek*MeV );
83 et = ek + amas;
84 p = std::sqrt( std::abs((et-amas)*(et+amas)) );
85 pp = modifiedOriginal.GetMomentum().mag()/MeV;
86 if( pp > 0.0 )
87 {
88 G4ThreeVector momentum = modifiedOriginal.GetMomentum();
89 modifiedOriginal.SetMomentum( momentum * (p/pp) );
90 }
91 G4ReactionProduct currentParticle = modifiedOriginal;
92 G4ReactionProduct targetParticle;
93 targetParticle = *originalTarget;
94 currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere
95 targetParticle.SetSide( -1 ); // target always goes in backward hemisphere
96 G4bool incidentHasChanged = false;
97 G4bool targetHasChanged = false;
98 G4bool quasiElastic = false;
99 G4FastVector<G4ReactionProduct,GHADLISTSIZE> vec; // vec will contain the secondary particles
100 G4int vecLen = 0;
101 vec.Initialize( 0 );
102
103 const G4double cutOff = 0.1;
104 if( currentParticle.GetKineticEnergy()/MeV > cutOff )
105 Cascade( vec, vecLen,
106 originalIncident, currentParticle, targetParticle,
107 incidentHasChanged, targetHasChanged, quasiElastic );
108
109 CalculateMomenta( vec, vecLen,
110 originalIncident, originalTarget, modifiedOriginal,
111 targetNucleus, currentParticle, targetParticle,
112 incidentHasChanged, targetHasChanged, quasiElastic );
113
114 SetUpChange( vec, vecLen,
115 currentParticle, targetParticle,
116 incidentHasChanged );
117
118 delete originalTarget;
119 return &theParticleChange;
120 }
121
122 void
123 G4LEKaonZeroInelastic::Cascade(
124 G4FastVector<G4ReactionProduct,GHADLISTSIZE> &vec,
125 G4int& vecLen,
126 const G4HadProjectile *originalIncident,
127 G4ReactionProduct &currentParticle,
128 G4ReactionProduct &targetParticle,
129 G4bool &incidentHasChanged,
130 G4bool &targetHasChanged,
131 G4bool &quasiElastic )
132 {
133 // derived from original FORTRAN code CASK0 by H. Fesefeldt (13-Sep-1987)
134 //
135 // K0Short undergoes interaction with nucleon within a nucleus. Check if it is
136 // energetically possible to produce pions/kaons. In not, assume nuclear excitation
137 // occurs and input particle is degraded in energy. No other particles are produced.
138 // If reaction is possible, find the correct number of pions/protons/neutrons
139 // produced using an interpolation to multiplicity data. Replace some pions or
140 // protons/neutrons by kaons or strange baryons according to the average
141 // multiplicity per Inelastic reaction.
142 //
143 const G4double mOriginal = originalIncident->GetDefinition()->GetPDGMass()/MeV;
144 const G4double etOriginal = originalIncident->GetTotalEnergy()/MeV;
145 const G4double targetMass = targetParticle.GetMass()/MeV;
146 G4double centerofmassEnergy = std::sqrt( mOriginal*mOriginal +
147 targetMass*targetMass +
148 2.0*targetMass*etOriginal );
149 G4double availableEnergy = centerofmassEnergy-(targetMass+mOriginal);
150 if( availableEnergy <= G4PionPlus::PionPlus()->GetPDGMass()/MeV )
151 {
152 quasiElastic = true;
153 return;
154 }
155 static G4bool first = true;
156 const G4int numMul = 1200;
157 const G4int numSec = 60;
158 static G4double protmul[numMul], protnorm[numSec]; // proton constants
159 static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
160 // np = number of pi+, nm = number of pi-, nz = number of pi0
161 G4int counter, nt=0, np=0, nm=0, nz=0;
162 const G4double c = 1.25;
163 const G4double b[] = { 0.7, 0.7 };
164 if( first ) // compute normalization constants, this will only be Done once
165 {
166 first = false;
167 G4int i;
168 for( i=0; i<numMul; ++i )protmul[i] = 0.0;
169 for( i=0; i<numSec; ++i )protnorm[i] = 0.0;
170 counter = -1;
171 for( np=0; np<(numSec/3); ++np )
172 {
173 for( nm=std::max(0,np-1); nm<=(np+1); ++nm )
174 {
175 for( nz=0; nz<numSec/3; ++nz )
176 {
177 if( ++counter < numMul )
178 {
179 nt = np+nm+nz;
180 if( nt>0 && nt<=numSec )
181 {
182 protmul[counter] = Pmltpc(np,nm,nz,nt,b[0],c);
183 protnorm[nt-1] += protmul[counter];
184 }
185 }
186 }
187 }
188 }
189 for( i=0; i<numMul; ++i )neutmul[i] = 0.0;
190 for( i=0; i<numSec; ++i )neutnorm[i] = 0.0;
191 counter = -1;
192 for( np=0; np<numSec/3; ++np )
193 {
194 for( nm=std::max(0,np-2); nm<=np; ++nm )
195 {
196 for( nz=0; nz<numSec/3; ++nz )
197 {
198 if( ++counter < numMul )
199 {
200 nt = np+nm+nz;
201 if( nt>0 && nt<=numSec )
202 {
203 neutmul[counter] = Pmltpc(np,nm,nz,nt,b[1],c);
204 neutnorm[nt-1] += neutmul[counter];
205 }
206 }
207 }
208 }
209 }
210 for( i=0; i<numSec; ++i )
211 {
212 if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
213 if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
214 }
215 } // end of initialization
216
217 const G4double expxu = 82.; // upper bound for arg. of exp
218 const G4double expxl = -expxu; // lower bound for arg. of exp
219 G4ParticleDefinition *aKaonPlus = G4KaonPlus::KaonPlus();
220 G4ParticleDefinition *aKaonZL = G4KaonZeroLong::KaonZeroLong();
221 G4ParticleDefinition *aKaonZS = G4KaonZeroShort::KaonZeroShort();
222 G4ParticleDefinition *aNeutron = G4Neutron::Neutron();
223 G4ParticleDefinition *aProton = G4Proton::Proton();
224 G4int ieab = static_cast<G4int>(5.0*availableEnergy*MeV/GeV);
225 const G4double supp[] = {0.,0.4,0.55,0.65,0.75,0.82,0.86,0.90,0.94,0.98};
226 G4double test, w0, wp, wt, wm;
227 if( (availableEnergy*MeV/GeV < 2.0) && (G4UniformRand() >= supp[ieab]) )
228 {
229 //
230 // suppress high multiplicity events at low momentum
231 // only one pion will be produced
232 //
233 nm = np = nz = 0;
234 if( targetParticle.GetDefinition() == aNeutron )
235 {
236 test = std::exp( std::min( expxu, std::max( expxl, -(1.0+b[0])*(1.0+b[0])/(2.0*c*c) ) ) );
237 w0 = test/2.0;
238 test = std::exp( std::min( expxu, std::max( expxl, -(-1.0+b[0])*(1.0+b[0])/(2.0*c*c) ) ) );
239 wm = test*1.5;
240 if( G4UniformRand() < w0/(w0+wm) )
241 nz = 1;
242 else
243 nm = 1;
244 }
245 else // target is a proton
246 {
247 test = std::exp( std::min( expxu, std::max( expxl, -(1.0+b[1])*(1.0+b[1])/(2.0*c*c) ) ) );
248 w0 = test;
249 wp = test;
250 test = std::exp( std::min( expxu, std::max( expxl, -(-1.0+b[1])*(-1.0+b[1])/(2.0*c*c) ) ) );
251 wm = test;
252 wt = w0+wp+wm;
253 wp += w0;
254 G4double ran = G4UniformRand();
255 if( ran < w0/wt )
256 nz = 1;
257 else if( ran < wp/wt )
258 np = 1;
259 else
260 nm = 1;
261 }
262 }
263 else // (availableEnergy*MeV/GeV >= 2.0) || (G4UniformRand() < supp[ieab])
264 {
265 G4double n, anpn;
266 GetNormalizationConstant( availableEnergy, n, anpn );
267 G4double ran = G4UniformRand();
268 G4double dum, excs = 0.0;
269 if( targetParticle.GetDefinition() == aProton )
270 {
271 counter = -1;
272 for( np=0; np<numSec/3 && ran>=excs; ++np )
273 {
274 for( nm=std::max(0,np-1); nm<=(np+1) && ran>=excs; ++nm )
275 {
276 for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
277 {
278 if( ++counter < numMul )
279 {
280 nt = np+nm+nz;
281 if( nt>0 && nt<=numSec )
282 {
283 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
284 dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
285 if( std::fabs(dum) < 1.0 )
286 {
287 if( test >= 1.0e-10 )excs += dum*test;
288 }
289 else
290 excs += dum*test;
291 }
292 }
293 }
294 }
295 }
296 if( ran >= excs ) // 3 previous loops continued to the end
297 {
298 quasiElastic = true;
299 return;
300 }
301 np--; nm--; nz--;
302 }
303 else // target must be a neutron
304 {
305 counter = -1;
306 for( np=0; np<numSec/3 && ran>=excs; ++np )
307 {
308 for( nm=std::max(0,np-2); nm<=np && ran>=excs; ++nm )
309 {
310 for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
311 {
312 if( ++counter < numMul )
313 {
314 nt = np+nm+nz;
315 if( nt>0 && nt<=numSec )
316 {
317 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
318 dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
319 if( std::fabs(dum) < 1.0 )
320 {
321 if( test >= 1.0e-10 )excs += dum*test;
322 }
323 else
324 excs += dum*test;
325 }
326 }
327 }
328 }
329 }
330 if( ran >= excs ) // 3 previous loops continued to the end
331 {
332 quasiElastic = true;
333 return;
334 }
335 np--; nm--; nz--;
336 }
337 }
338 if( targetParticle.GetDefinition() == aProton )
339 {
340 switch( np-nm )
341 {
342 case 0:
343 if( G4UniformRand() < 0.25 )
344 {
345 currentParticle.SetDefinitionAndUpdateE( aKaonPlus );
346 targetParticle.SetDefinitionAndUpdateE( aNeutron );
347 incidentHasChanged = true;
348 targetHasChanged = true;
349 }
350 break;
351 case 1:
352 targetParticle.SetDefinitionAndUpdateE( aNeutron );
353 targetHasChanged = true;
354 break;
355 default:
356 targetParticle.SetDefinitionAndUpdateE( aNeutron );
357 targetHasChanged = true;
358 break;
359 }
360 }
361 else // targetParticle is a neutron
362 {
363 switch( np-nm ) // seems wrong, charge not conserved
364 {
365 case 1:
366 if( G4UniformRand() < 0.5 )
367 {
368 currentParticle.SetDefinitionAndUpdateE( aKaonPlus );
369 incidentHasChanged = true;
370 }
371 else
372 {
373 targetParticle.SetDefinitionAndUpdateE( aProton );
374 targetHasChanged = true;
375 }
376 break;
377 case 2:
378 currentParticle.SetDefinitionAndUpdateE( aKaonPlus );
379 incidentHasChanged = true;
380 targetParticle.SetDefinitionAndUpdateE( aProton );
381 targetHasChanged = true;
382 break;
383 default:
384 break;
385 }
386 }
387 if( currentParticle.GetDefinition() == aKaonZS )
388 {
389 if( G4UniformRand() >= 0.5 )
390 {
391 currentParticle.SetDefinitionAndUpdateE( aKaonZL);
392 incidentHasChanged = true;
393 }
394 }
395 if( targetParticle.GetDefinition() == aKaonZS )
396 {
397 if( G4UniformRand() >= 0.5 )
398 {
399 targetParticle.SetDefinitionAndUpdateE( aKaonZL );
400 targetHasChanged = true;
401 }
402 }
403 SetUpPions( np, nm, nz, vec, vecLen );
404 return;
405 }
406
407 /* end of file */
408
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