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G4HEKaonZeroInelastic.cc
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26 // $Id$
27 //
28 
29 // G4 Process: Gheisha High Energy Collision model.
30 // This includes the high energy cascading model, the two-body-resonance model
31 // and the low energy two-body model. Not included are the low energy stuff
32 // like nuclear reactions, nuclear fission without any cascading and all
33 // processes for particles at rest.
34 // First work done by J.L.Chuma and F.W.Jones, TRIUMF, June 96.
35 // H. Fesefeldt, RWTH-Aachen, 23-October-1996
36 
37 #include "G4HEKaonZeroInelastic.hh"
38 #include "globals.hh"
39 #include "G4ios.hh"
40 #include "G4PhysicalConstants.hh"
41 
42 void G4HEKaonZeroInelastic::ModelDescription(std::ostream& outFile) const
43 {
44  outFile << "G4HEKaonZeroInelastic is one of the High Energy\n"
45  << "Parameterized (HEP) models used to implement inelastic\n"
46  << "K0 scattering from nuclei. It is a re-engineered\n"
47  << "version of the GHEISHA code of H. Fesefeldt. It divides the\n"
48  << "initial collision products into backward- and forward-going\n"
49  << "clusters which are then decayed into final state hadrons.\n"
50  << "The model does not conserve energy on an event-by-event\n"
51  << "basis. It may be applied to K0 with initial energies\n"
52  << "above 20 GeV.\n";
53 }
54 
55 
56 G4HadFinalState*
57 G4HEKaonZeroInelastic::ApplyYourself(const G4HadProjectile& aTrack,
58  G4Nucleus& targetNucleus)
59 {
60  G4HEVector* pv = new G4HEVector[MAXPART];
61  const G4HadProjectile* aParticle = &aTrack;
62  const G4double A = targetNucleus.GetA_asInt();
63  const G4double Z = targetNucleus.GetZ_asInt();
64  G4HEVector incidentParticle(aParticle);
65 
66  G4double atomicNumber = Z;
67  G4double atomicWeight = A;
68 
69  G4int incidentCode = incidentParticle.getCode();
70  G4double incidentMass = incidentParticle.getMass();
71  G4double incidentTotalEnergy = incidentParticle.getEnergy();
72 
73  // G4double incidentTotalMomentum = incidentParticle.getTotalMomentum();
74  // DHW 19 May 2011: variable set but not used
75 
76  G4double incidentKineticEnergy = incidentTotalEnergy - incidentMass;
77 
78  if (incidentKineticEnergy < 1.)
79  G4cout << "GHEKaonZeroInelastic: incident energy < 1 GeV" << G4endl;;
80 
81  if (verboseLevel > 1) {
82  G4cout << "G4HEKaonZeroInelastic::ApplyYourself" << G4endl;
83  G4cout << "incident particle " << incidentParticle.getName()
84  << "mass " << incidentMass
85  << "kinetic energy " << incidentKineticEnergy
86  << G4endl;
87  G4cout << "target material with (A,Z) = ("
88  << atomicWeight << "," << atomicNumber << ")" << G4endl;
89  }
90 
91  G4double inelasticity = NuclearInelasticity(incidentKineticEnergy,
92  atomicWeight, atomicNumber);
93  if (verboseLevel > 1)
94  G4cout << "nuclear inelasticity = " << inelasticity << G4endl;
95 
96  incidentKineticEnergy -= inelasticity;
97 
98  G4double excitationEnergyGNP = 0.;
99  G4double excitationEnergyDTA = 0.;
100 
101  G4double excitation = NuclearExcitation(incidentKineticEnergy,
102  atomicWeight, atomicNumber,
103  excitationEnergyGNP,
104  excitationEnergyDTA);
105  if (verboseLevel > 1)
106  G4cout << "nuclear excitation = " << excitation << excitationEnergyGNP
107  << excitationEnergyDTA << G4endl;
108 
109  incidentKineticEnergy -= excitation;
110  incidentTotalEnergy = incidentKineticEnergy + incidentMass;
111  // incidentTotalMomentum = std::sqrt( (incidentTotalEnergy-incidentMass)
112  // *(incidentTotalEnergy+incidentMass));
113  // DHW 19 May 2011: variable set but not used
114 
115  G4HEVector targetParticle;
116  if (G4UniformRand() < atomicNumber/atomicWeight) {
117  targetParticle.setDefinition("Proton");
118  } else {
119  targetParticle.setDefinition("Neutron");
120  }
121 
122  G4double targetMass = targetParticle.getMass();
123  G4double centerOfMassEnergy = std::sqrt(incidentMass*incidentMass
124  + targetMass*targetMass
125  + 2.0*targetMass*incidentTotalEnergy);
126  G4double availableEnergy = centerOfMassEnergy - targetMass - incidentMass;
127 
128  G4bool inElastic = true;
129  vecLength = 0;
130 
131  if (verboseLevel > 1)
132  G4cout << "ApplyYourself: CallFirstIntInCascade for particle "
133  << incidentCode << G4endl;
134 
135  G4bool successful = false;
136 
137  FirstIntInCasKaonZero(inElastic, availableEnergy, pv, vecLength,
138  incidentParticle, targetParticle, atomicWeight);
139 
140  if (verboseLevel > 1)
141  G4cout << "ApplyYourself::StrangeParticlePairProduction" << G4endl;
142 
143  if ((vecLength > 0) && (availableEnergy > 1.))
144  StrangeParticlePairProduction(availableEnergy, centerOfMassEnergy,
145  pv, vecLength,
146  incidentParticle, targetParticle);
147 
148  HighEnergyCascading(successful, pv, vecLength,
149  excitationEnergyGNP, excitationEnergyDTA,
150  incidentParticle, targetParticle,
151  atomicWeight, atomicNumber);
152  if (!successful)
153  HighEnergyClusterProduction(successful, pv, vecLength,
154  excitationEnergyGNP, excitationEnergyDTA,
155  incidentParticle, targetParticle,
156  atomicWeight, atomicNumber);
157  if (!successful)
158  MediumEnergyCascading(successful, pv, vecLength,
159  excitationEnergyGNP, excitationEnergyDTA,
160  incidentParticle, targetParticle,
161  atomicWeight, atomicNumber);
162 
163  if (!successful)
164  MediumEnergyClusterProduction(successful, pv, vecLength,
165  excitationEnergyGNP, excitationEnergyDTA,
166  incidentParticle, targetParticle,
167  atomicWeight, atomicNumber);
168  if (!successful)
169  QuasiElasticScattering(successful, pv, vecLength,
170  excitationEnergyGNP, excitationEnergyDTA,
171  incidentParticle, targetParticle,
172  atomicWeight, atomicNumber);
173  if (!successful)
174  ElasticScattering(successful, pv, vecLength,
175  incidentParticle,
176  atomicWeight, atomicNumber);
177 
178  if (!successful)
179  G4cout << "GHEInelasticInteraction::ApplyYourself fails to produce final state particles"
180  << G4endl;
181 
182  FillParticleChange(pv, vecLength);
183 
184  delete [] pv;
185  theParticleChange.SetStatusChange(stopAndKill);
186  return &theParticleChange;
187 }
188 
189 
190 void
191 G4HEKaonZeroInelastic::FirstIntInCasKaonZero(G4bool& inElastic,
192  const G4double availableEnergy,
193  G4HEVector pv[],
194  G4int& vecLen,
195  const G4HEVector& incidentParticle,
196  const G4HEVector& targetParticle,
197  const G4double atomicWeight)
198 
199 // Kaon0 undergoes interaction with nucleon within a nucleus. Check if it is
200 // energetically possible to produce pions/kaons. In not, assume nuclear excitation
201 // occurs and input particle is degraded in energy. No other particles are produced.
202 // If reaction is possible, find the correct number of pions/protons/neutrons
203 // produced using an interpolation to multiplicity data. Replace some pions or
204 // protons/neutrons by kaons or strange baryons according to the average
205 // multiplicity per inelastic reaction.
206 {
207  static const G4double expxu = 82.; // upper bound for arg. of exp
208  static const G4double expxl = -expxu; // lower bound for arg. of exp
209 
210  static const G4double protb = 0.7;
211  static const G4double neutb = 0.7;
212  static const G4double c = 1.25;
213 
214  static const G4int numMul = 1200;
215  static const G4int numSec = 60;
216 
217  G4int neutronCode = Neutron.getCode();
218  G4int protonCode = Proton.getCode();
219 
220  G4int targetCode = targetParticle.getCode();
221  G4double incidentTotalMomentum = incidentParticle.getTotalMomentum();
222 
223  static G4bool first = true;
224  static G4double protmul[numMul], protnorm[numSec]; // proton constants
225  static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
226 
227  // misc. local variables
228  // npos = number of pi+, nneg = number of pi-, nzero = number of pi0
229 
230  G4int i, counter, nt, npos, nneg, nzero;
231 
232  if( first )
233  { // compute normalization constants, this will only be done once
234  first = false;
235  for( i=0; i<numMul; i++ )protmul[i] = 0.0;
236  for( i=0; i<numSec; i++ )protnorm[i] = 0.0;
237  counter = -1;
238  for( npos=0; npos<(numSec/3); npos++ )
239  {
240  for( nneg=std::max(0,npos-1); nneg<=(npos+1); nneg++ )
241  {
242  for( nzero=0; nzero<numSec/3; nzero++ )
243  {
244  if( ++counter < numMul )
245  {
246  nt = npos+nneg+nzero;
247  if( (nt>0) && (nt<=numSec) )
248  {
249  protmul[counter] =
250  pmltpc(npos,nneg,nzero,nt,protb,c) ;
251  protnorm[nt-1] += protmul[counter];
252  }
253  }
254  }
255  }
256  }
257  for( i=0; i<numMul; i++ )neutmul[i] = 0.0;
258  for( i=0; i<numSec; i++ )neutnorm[i] = 0.0;
259  counter = -1;
260  for( npos=0; npos<numSec/3; npos++ )
261  {
262  for( nneg=npos; nneg<=(npos+2); nneg++ )
263  {
264  for( nzero=0; nzero<numSec/3; nzero++ )
265  {
266  if( ++counter < numMul )
267  {
268  nt = npos+nneg+nzero;
269  if( (nt>0) && (nt<=numSec) )
270  {
271  neutmul[counter] =
272  pmltpc(npos,nneg,nzero,nt,neutb,c);
273  neutnorm[nt-1] += neutmul[counter];
274  }
275  }
276  }
277  }
278  }
279  for( i=0; i<numSec; i++ )
280  {
281  if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
282  if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
283  }
284  } // end of initialization
285 
286 
287  // initialize the first two places
288  // the same as beam and target
289  pv[0] = incidentParticle;
290  pv[1] = targetParticle;
291  vecLen = 2;
292 
293  if( !inElastic )
294  { // quasi-elastic scattering, no pions produced
295  if( targetCode == protonCode )
296  {
297  G4double cech[] = {0.33,0.27,0.29,0.31,0.27,0.18,0.13,0.10,0.09,0.07};
298  G4int iplab = G4int( std::min( 9.0, incidentTotalMomentum*5. ) );
299  if( G4UniformRand() < cech[iplab]/std::pow(atomicWeight,0.42) )
300  { // charge exchange K+ n -> K0 p
301  pv[0] = KaonPlus;
302  pv[1] = Neutron;
303  }
304  }
305  return;
306  }
307  else if (availableEnergy <= PionPlus.getMass())
308  return;
309 
310  // inelastic scattering
311 
312  npos = 0, nneg = 0, nzero = 0;
313  G4double eab = availableEnergy;
314  G4int ieab = G4int( eab*5.0 );
315 
316  G4double supp[] = {0., 0.4, 0.55, 0.65, 0.75, 0.82, 0.86, 0.90, 0.94, 0.98};
317  if( (ieab <= 9) && (G4UniformRand() >= supp[ieab]) )
318  {
319 // suppress high multiplicity events at low momentum
320 // only one additional pion will be produced
321  G4double w0, wp, wm, wt, ran;
322  if( targetCode == neutronCode ) // target is a neutron
323  {
324  w0 = - sqr(1.+protb)/(2.*c*c);
325  w0 = std::exp(w0);
326  wm = - sqr(-1.+protb)/(2.*c*c);
327  wm = std::exp(wm);
328  w0 = w0/2.;
329  wm = wm*1.5;
330  if( G4UniformRand() < w0/(w0+wm) ) { npos = 0; nneg = 0; nzero = 1; }
331  else
332  { npos = 0; nneg = 1; nzero = 0; }
333  }
334  else
335  { // target is a proton
336  w0 = -sqr(1.+neutb)/(2.*c*c);
337  wp = w0 = std::exp(w0);
338  wm = -sqr(-1.+neutb)/(2.*c*c);
339  wm = std::exp(wm);
340  wt = w0+wp+wm;
341  wp = w0+wp;
342  ran = G4UniformRand();
343  if( ran < w0/wt)
344  { npos = 0; nneg = 0; nzero = 1; }
345  else if( ran < wp/wt)
346  { npos = 1; nneg = 0; nzero = 0; }
347  else
348  { npos = 0; nneg = 1; nzero = 0; }
349  }
350  }
351  else
352  {
353 // number of total particles vs. centre of mass Energy - 2*proton mass
354 
355  G4double aleab = std::log(availableEnergy);
356  G4double n = 3.62567+aleab*(0.665843+aleab*(0.336514
357  + aleab*(0.117712+0.0136912*aleab))) - 2.0;
358 
359 // normalization constant for kno-distribution.
360 // calculate first the sum of all constants, check for numerical problems.
361  G4double test, dum, anpn = 0.0;
362 
363  for (nt=1; nt<=numSec; nt++) {
364  test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
365  dum = pi*nt/(2.0*n*n);
366  if (std::fabs(dum) < 1.0) {
367  if( test >= 1.0e-10 )anpn += dum*test;
368  } else {
369  anpn += dum*test;
370  }
371  }
372 
373  G4double ran = G4UniformRand();
374  G4double excs = 0.0;
375  if( targetCode == protonCode )
376  {
377  counter = -1;
378  for( npos=0; npos<numSec/3; npos++ )
379  {
380  for( nneg=std::max(0,npos-1); nneg<=(npos+1); nneg++ )
381  {
382  for (nzero=0; nzero<numSec/3; nzero++) {
383  if (++counter < numMul) {
384  nt = npos+nneg+nzero;
385  if ( (nt>0) && (nt<=numSec) ) {
386  test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
387  dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
388  if (std::fabs(dum) < 1.0) {
389  if( test >= 1.0e-10 )excs += dum*test;
390  } else {
391  excs += dum*test;
392  }
393  if (ran < excs) goto outOfLoop; //----------------------->
394  }
395  }
396  }
397  }
398  }
399 
400  // 3 previous loops continued to the end
401  inElastic = false; // quasi-elastic scattering
402  return;
403  }
404  else
405  { // target must be a neutron
406  counter = -1;
407  for( npos=0; npos<numSec/3; npos++ )
408  {
409  for( nneg=npos; nneg<=(npos+2); nneg++ )
410  {
411  for (nzero=0; nzero<numSec/3; nzero++) {
412  if (++counter < numMul) {
413  nt = npos+nneg+nzero;
414  if ( (nt>=1) && (nt<=numSec) ) {
415  test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
416  dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
417  if (std::fabs(dum) < 1.0) {
418  if( test >= 1.0e-10 )excs += dum*test;
419  } else {
420  excs += dum*test;
421  }
422  if (ran < excs) goto outOfLoop; // -------------------------->
423  }
424  }
425  }
426  }
427  }
428  // 3 previous loops continued to the end
429  inElastic = false; // quasi-elastic scattering.
430  return;
431  }
432  }
433  outOfLoop: // <-----------------------------------------------
434 
435  if( targetCode == neutronCode)
436  {
437  if( npos == nneg)
438  {
439  }
440  else if (npos == (nneg-1))
441  {
442  if( G4UniformRand() < 0.5)
443  {
444  pv[0] = KaonPlus;
445  }
446  else
447  {
448  pv[1] = Proton;
449  }
450  }
451  else
452  {
453  pv[0] = KaonPlus;
454  pv[1] = Proton;
455  }
456  }
457  else
458  {
459  if( npos == nneg )
460  {
461  if( G4UniformRand() < 0.25)
462  {
463  pv[0] = KaonPlus;
464  pv[1] = Neutron;
465  }
466  else
467  {
468  }
469  }
470  else if ( npos == (nneg+1))
471  {
472  pv[1] = Neutron;
473  }
474  else
475  {
476  pv[0] = KaonPlus;
477  }
478  }
479 
480 
481  nt = npos + nneg + nzero;
482  while ( nt > 0)
483  {
484  G4double ran = G4UniformRand();
485  if ( ran < (G4double)npos/nt)
486  {
487  if( npos > 0 )
488  { pv[vecLen++] = PionPlus;
489  npos--;
490  }
491  }
492  else if ( ran < (G4double)(npos+nneg)/nt)
493  {
494  if( nneg > 0 )
495  {
496  pv[vecLen++] = PionMinus;
497  nneg--;
498  }
499  }
500  else
501  {
502  if( nzero > 0 )
503  {
504  pv[vecLen++] = PionZero;
505  nzero--;
506  }
507  }
508  nt = npos + nneg + nzero;
509  }
510  if (verboseLevel > 1)
511  {
512  G4cout << "Particles produced: " ;
513  G4cout << pv[0].getName() << " " ;
514  G4cout << pv[1].getName() << " " ;
515  for (i=2; i < vecLen; i++)
516  {
517  G4cout << pv[i].getName() << " " ;
518  }
519  G4cout << G4endl;
520  }
521  return; }
522 
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