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G4RPGKZeroInelastic.cc
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26 // $Id$
27 //
28 
29 #include "G4RPGKZeroInelastic.hh"
30 #include "G4PhysicalConstants.hh"
31 #include "G4SystemOfUnits.hh"
32 #include "Randomize.hh"
33 
36  G4Nucleus &targetNucleus )
37 {
38  const G4HadProjectile *originalIncident = &aTrack;
39 
40  // create the target particle
41 
42  G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle();
43 
44  if( verboseLevel > 1 )
45  {
46  const G4Material *targetMaterial = aTrack.GetMaterial();
47  G4cout << "G4RPGKZeroInelastic::ApplyYourself called" << G4endl;
48  G4cout << "kinetic energy = " << originalIncident->GetKineticEnergy()/MeV << "MeV, ";
49  G4cout << "target material = " << targetMaterial->GetName() << ", ";
50  G4cout << "target particle = " << originalTarget->GetDefinition()->GetParticleName()
51  << G4endl;
52  }
53 
54  // Fermi motion and evaporation
55  // As of Geant3, the Fermi energy calculation had not been Done
56 
57  G4double ek = originalIncident->GetKineticEnergy()/MeV;
58  G4double amas = originalIncident->GetDefinition()->GetPDGMass()/MeV;
59  G4ReactionProduct modifiedOriginal;
60  modifiedOriginal = *originalIncident;
61 
62  G4double tkin = targetNucleus.Cinema( ek );
63  ek += tkin;
64  modifiedOriginal.SetKineticEnergy( ek*MeV );
65  G4double et = ek + amas;
66  G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) );
67  G4double pp = modifiedOriginal.GetMomentum().mag()/MeV;
68  if( pp > 0.0 )
69  {
70  G4ThreeVector momentum = modifiedOriginal.GetMomentum();
71  modifiedOriginal.SetMomentum( momentum * (p/pp) );
72  }
73  //
74  // calculate black track energies
75  //
76  tkin = targetNucleus.EvaporationEffects( ek );
77  ek -= tkin;
78  modifiedOriginal.SetKineticEnergy( ek*MeV );
79  et = ek + amas;
80  p = std::sqrt( std::abs((et-amas)*(et+amas)) );
81  pp = modifiedOriginal.GetMomentum().mag()/MeV;
82  if( pp > 0.0 )
83  {
84  G4ThreeVector momentum = modifiedOriginal.GetMomentum();
85  modifiedOriginal.SetMomentum( momentum * (p/pp) );
86  }
87  G4ReactionProduct currentParticle = modifiedOriginal;
88  G4ReactionProduct targetParticle;
89  targetParticle = *originalTarget;
90  currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere
91  targetParticle.SetSide( -1 ); // target always goes in backward hemisphere
92  G4bool incidentHasChanged = false;
93  G4bool targetHasChanged = false;
94  G4bool quasiElastic = false;
95  G4FastVector<G4ReactionProduct,GHADLISTSIZE> vec; // vec will contain the secondary particles
96  G4int vecLen = 0;
97  vec.Initialize( 0 );
98 
99  const G4double cutOff = 0.1;
100  if( currentParticle.GetKineticEnergy()/MeV > cutOff )
101  Cascade( vec, vecLen,
102  originalIncident, currentParticle, targetParticle,
103  incidentHasChanged, targetHasChanged, quasiElastic );
104 
105  CalculateMomenta( vec, vecLen,
106  originalIncident, originalTarget, modifiedOriginal,
107  targetNucleus, currentParticle, targetParticle,
108  incidentHasChanged, targetHasChanged, quasiElastic );
109 
110  SetUpChange( vec, vecLen,
111  currentParticle, targetParticle,
112  incidentHasChanged );
113 
114  delete originalTarget;
115  return &theParticleChange;
116 }
117 
118 void G4RPGKZeroInelastic::Cascade(
120  G4int& vecLen,
121  const G4HadProjectile *originalIncident,
122  G4ReactionProduct &currentParticle,
123  G4ReactionProduct &targetParticle,
124  G4bool &incidentHasChanged,
125  G4bool &targetHasChanged,
126  G4bool &quasiElastic )
127 {
128  // Derived from H. Fesefeldt's original FORTRAN code CASK0
129  //
130  // K0Short undergoes interaction with nucleon within a nucleus. Check if it is
131  // energetically possible to produce pions/kaons. In not, assume nuclear excitation
132  // occurs and input particle is degraded in energy. No other particles are produced.
133  // If reaction is possible, find the correct number of pions/protons/neutrons
134  // produced using an interpolation to multiplicity data. Replace some pions or
135  // protons/neutrons by kaons or strange baryons according to the average
136  // multiplicity per Inelastic reaction.
137 
138  const G4double mOriginal = originalIncident->GetDefinition()->GetPDGMass()/MeV;
139  const G4double etOriginal = originalIncident->GetTotalEnergy()/MeV;
140  const G4double targetMass = targetParticle.GetMass()/MeV;
141  G4double centerofmassEnergy = std::sqrt( mOriginal*mOriginal +
142  targetMass*targetMass +
143  2.0*targetMass*etOriginal );
144  G4double availableEnergy = centerofmassEnergy-(targetMass+mOriginal);
145  if( availableEnergy <= G4PionPlus::PionPlus()->GetPDGMass()/MeV )
146  {
147  quasiElastic = true;
148  return;
149  }
150  static G4bool first = true;
151  const G4int numMul = 1200;
152  const G4int numSec = 60;
153  static G4double protmul[numMul], protnorm[numSec]; // proton constants
154  static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
155  // np = number of pi+, nneg = number of pi-, nz = number of pi0
156  G4int counter, nt=0, np=0, nneg=0, nz=0;
157  const G4double c = 1.25;
158  const G4double b[] = { 0.7, 0.7 };
159  if( first ) // compute normalization constants, this will only be Done once
160  {
161  first = false;
162  G4int i;
163  for( i=0; i<numMul; ++i )protmul[i] = 0.0;
164  for( i=0; i<numSec; ++i )protnorm[i] = 0.0;
165  counter = -1;
166  for( np=0; np<(numSec/3); ++np )
167  {
168  for( nneg=std::max(0,np-1); nneg<=(np+1); ++nneg )
169  {
170  for( nz=0; nz<numSec/3; ++nz )
171  {
172  if( ++counter < numMul )
173  {
174  nt = np+nneg+nz;
175  if( nt>0 && nt<=numSec )
176  {
177  protmul[counter] = Pmltpc(np,nneg,nz,nt,b[0],c);
178  protnorm[nt-1] += protmul[counter];
179  }
180  }
181  }
182  }
183  }
184  for( i=0; i<numMul; ++i )neutmul[i] = 0.0;
185  for( i=0; i<numSec; ++i )neutnorm[i] = 0.0;
186  counter = -1;
187  for( np=0; np<numSec/3; ++np )
188  {
189  for( nneg=std::max(0,np-2); nneg<=np; ++nneg )
190  {
191  for( nz=0; nz<numSec/3; ++nz )
192  {
193  if( ++counter < numMul )
194  {
195  nt = np+nneg+nz;
196  if( nt>0 && nt<=numSec )
197  {
198  neutmul[counter] = Pmltpc(np,nneg,nz,nt,b[1],c);
199  neutnorm[nt-1] += neutmul[counter];
200  }
201  }
202  }
203  }
204  }
205  for( i=0; i<numSec; ++i )
206  {
207  if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
208  if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
209  }
210  } // end of initialization
211 
212  const G4double expxu = 82.; // upper bound for arg. of exp
213  const G4double expxl = -expxu; // lower bound for arg. of exp
219  G4int ieab = static_cast<G4int>(5.0*availableEnergy*MeV/GeV);
220  const G4double supp[] = {0.,0.4,0.55,0.65,0.75,0.82,0.86,0.90,0.94,0.98};
221  G4double test, w0, wp, wt, wm;
222  if( (availableEnergy*MeV/GeV < 2.0) && (G4UniformRand() >= supp[ieab]) )
223  {
224  //
225  // suppress high multiplicity events at low momentum
226  // only one pion will be produced
227  //
228  nneg = np = nz = 0;
229  if( targetParticle.GetDefinition() == aNeutron )
230  {
231  test = std::exp( std::min( expxu, std::max( expxl, -(1.0+b[0])*(1.0+b[0])/(2.0*c*c) ) ) );
232  w0 = test/2.0;
233  test = std::exp( std::min( expxu, std::max( expxl, -(-1.0+b[0])*(1.0+b[0])/(2.0*c*c) ) ) );
234  wm = test*1.5;
235  if( G4UniformRand() < w0/(w0+wm) )
236  nz = 1;
237  else
238  nneg = 1;
239  }
240  else // target is a proton
241  {
242  test = std::exp( std::min( expxu, std::max( expxl, -(1.0+b[1])*(1.0+b[1])/(2.0*c*c) ) ) );
243  w0 = test;
244  wp = test;
245  test = std::exp( std::min( expxu, std::max( expxl, -(-1.0+b[1])*(-1.0+b[1])/(2.0*c*c) ) ) );
246  wm = test;
247  wt = w0+wp+wm;
248  wp += w0;
249  G4double ran = G4UniformRand();
250  if( ran < w0/wt )
251  nz = 1;
252  else if( ran < wp/wt )
253  np = 1;
254  else
255  nneg = 1;
256  }
257  }
258  else // (availableEnergy*MeV/GeV >= 2.0) || (G4UniformRand() < supp[ieab])
259  {
260  G4double n, anpn;
261  GetNormalizationConstant( availableEnergy, n, anpn );
262  G4double ran = G4UniformRand();
263  G4double dum, excs = 0.0;
264  if( targetParticle.GetDefinition() == aProton )
265  {
266  counter = -1;
267  for( np=0; np<numSec/3 && ran>=excs; ++np )
268  {
269  for( nneg=std::max(0,np-1); nneg<=(np+1) && ran>=excs; ++nneg )
270  {
271  for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
272  {
273  if( ++counter < numMul )
274  {
275  nt = np+nneg+nz;
276  if( nt>0 && nt<=numSec )
277  {
278  test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
279  dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
280  if( std::fabs(dum) < 1.0 )
281  {
282  if( test >= 1.0e-10 )excs += dum*test;
283  }
284  else
285  excs += dum*test;
286  }
287  }
288  }
289  }
290  }
291  if( ran >= excs ) // 3 previous loops continued to the end
292  {
293  quasiElastic = true;
294  return;
295  }
296  np--; nneg--; nz--;
297  }
298  else // target must be a neutron
299  {
300  counter = -1;
301  for( np=0; np<numSec/3 && ran>=excs; ++np )
302  {
303  for( nneg=std::max(0,np-2); nneg<=np && ran>=excs; ++nneg )
304  {
305  for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
306  {
307  if( ++counter < numMul )
308  {
309  nt = np+nneg+nz;
310  if( nt>0 && nt<=numSec )
311  {
312  test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
313  dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
314  if( std::fabs(dum) < 1.0 )
315  {
316  if( test >= 1.0e-10 )excs += dum*test;
317  }
318  else
319  excs += dum*test;
320  }
321  }
322  }
323  }
324  }
325  if( ran >= excs ) // 3 previous loops continued to the end
326  {
327  quasiElastic = true;
328  return;
329  }
330  np--; nneg--; nz--;
331  }
332  }
333  if( targetParticle.GetDefinition() == aProton )
334  {
335  switch( np-nneg )
336  {
337  case 0:
338  if( G4UniformRand() < 0.25 )
339  {
340  currentParticle.SetDefinitionAndUpdateE( aKaonPlus );
341  targetParticle.SetDefinitionAndUpdateE( aNeutron );
342  incidentHasChanged = true;
343  targetHasChanged = true;
344  }
345  break;
346  case 1:
347  targetParticle.SetDefinitionAndUpdateE( aNeutron );
348  targetHasChanged = true;
349  break;
350  default:
351  targetParticle.SetDefinitionAndUpdateE( aNeutron );
352  targetHasChanged = true;
353  break;
354  }
355  }
356  else // targetParticle is a neutron
357  {
358  switch( np-nneg ) // seems wrong, charge not conserved
359  {
360  case 1:
361  if( G4UniformRand() < 0.5 )
362  {
363  currentParticle.SetDefinitionAndUpdateE( aKaonPlus );
364  incidentHasChanged = true;
365  }
366  else
367  {
368  targetParticle.SetDefinitionAndUpdateE( aProton );
369  targetHasChanged = true;
370  }
371  break;
372  case 2:
373  currentParticle.SetDefinitionAndUpdateE( aKaonPlus );
374  incidentHasChanged = true;
375  targetParticle.SetDefinitionAndUpdateE( aProton );
376  targetHasChanged = true;
377  break;
378  default:
379  break;
380  }
381  }
382 
383  if (currentParticle.GetDefinition() == aKaonZS) {
384  if (G4UniformRand() >= 0.5) {
385  currentParticle.SetDefinitionAndUpdateE(aKaonZL);
386  incidentHasChanged = true;
387  }
388  }
389 
390  if (targetParticle.GetDefinition() == aKaonZS) {
391  if (G4UniformRand() >= 0.5) {
392  targetParticle.SetDefinitionAndUpdateE(aKaonZL);
393  targetHasChanged = true;
394  }
395  }
396 
397  SetUpPions( np, nneg, nz, vec, vecLen );
398  return;
399 }
400 
401  /* end of file */
402