source: trunk/source/processes/hadronic/models/low_energy/src/G4LEKaonPlusInelastic.cc@ 1036

Last change on this file since 1036 was 1007, checked in by garnier, 17 years ago

update to geant4.9.2
File size: 14.6 KB
Line 
1//
2// ********************************************************************
3// * License and Disclaimer *
4// * *
5// * The Geant4 software is copyright of the Copyright Holders of *
6// * the Geant4 Collaboration. It is provided under the terms and *
7// * conditions of the Geant4 Software License, included in the file *
8// * LICENSE and available at http://cern.ch/geant4/license . These *
9// * include a list of copyright holders. *
10// * *
11// * Neither the authors of this software system, nor their employing *
12// * institutes,nor the agencies providing financial support for this *
13// * work make any representation or warranty, express or implied, *
14// * regarding this software system or assume any liability for its *
15// * use. Please see the license in the file LICENSE and URL above *
16// * for the full disclaimer and the limitation of liability. *
17// * *
18// * This code implementation is the result of the scientific and *
19// * technical work of the GEANT4 collaboration. *
20// * By using, copying, modifying or distributing the software (or *
21// * any work based on the software) you agree to acknowledge its *
22// * use in resulting scientific publications, and indicate your *
23// * acceptance of all terms of the Geant4 Software license. *
24// ********************************************************************
25//
26//
27// $Id: G4LEKaonPlusInelastic.cc,v 1.13 2006/06/29 20:45:01 gunter Exp $
28// GEANT4 tag $Name: geant4-09-02 $
29//
30 // Hadronic Process: Low Energy KaonPlus Inelastic Process
31 // J.L. Chuma, TRIUMF, 05-Feb-1997
32 // Last modified: 27-Mar-1997
33 // Modified by J.L.Chuma 30-Apr-97: added originalTarget for CalculateMomenta
34
35#include "G4LEKaonPlusInelastic.hh"
36#include "Randomize.hh"
37
38 G4HadFinalState *
39 G4LEKaonPlusInelastic::ApplyYourself( const G4HadProjectile &aTrack,
40 G4Nucleus &targetNucleus )
41 {
42 const G4HadProjectile *originalIncident = &aTrack;
43 if (originalIncident->GetKineticEnergy()<= 0.1*MeV)
44 {
45 theParticleChange.SetStatusChange(isAlive);
46 theParticleChange.SetEnergyChange(aTrack.GetKineticEnergy());
47 theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit());
48 return &theParticleChange;
49 }
50
51 // create the target particle
52
53 G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle();
54 G4ReactionProduct targetParticle( originalTarget->GetDefinition() );
55
56 if( verboseLevel > 1 )
57 {
58 const G4Material *targetMaterial = aTrack.GetMaterial();
59 G4cout << "G4LEKaonPlusInelastic::ApplyYourself called" << G4endl;
60 G4cout << "kinetic energy = " << originalIncident->GetKineticEnergy() << "MeV, ";
61 G4cout << "target material = " << targetMaterial->GetName() << ", ";
62 G4cout << "target particle = " << originalTarget->GetDefinition()->GetParticleName()
63 << G4endl;
64 }
65 G4ReactionProduct currentParticle( const_cast<G4ParticleDefinition *>(originalIncident->GetDefinition()));
66 currentParticle.SetMomentum( originalIncident->Get4Momentum().vect() );
67 currentParticle.SetKineticEnergy( originalIncident->GetKineticEnergy() );
68
69 // Fermi motion and evaporation
70 // As of Geant3, the Fermi energy calculation had not been Done
71
72 G4double ek = originalIncident->GetKineticEnergy();
73 G4double amas = originalIncident->GetDefinition()->GetPDGMass();
74
75 G4double tkin = targetNucleus.Cinema( ek );
76 ek += tkin;
77 currentParticle.SetKineticEnergy( ek );
78 G4double et = ek + amas;
79 G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) );
80 G4double pp = currentParticle.GetMomentum().mag();
81 if( pp > 0.0 )
82 {
83 G4ThreeVector momentum = currentParticle.GetMomentum();
84 currentParticle.SetMomentum( momentum * (p/pp) );
85 }
86
87 // calculate black track energies
88
89 tkin = targetNucleus.EvaporationEffects( ek );
90 ek -= tkin;
91 currentParticle.SetKineticEnergy( ek );
92 et = ek + amas;
93 p = std::sqrt( std::abs((et-amas)*(et+amas)) );
94 pp = currentParticle.GetMomentum().mag();
95 if( pp > 0.0 )
96 {
97 G4ThreeVector momentum = currentParticle.GetMomentum();
98 currentParticle.SetMomentum( momentum * (p/pp) );
99 }
100
101 G4ReactionProduct modifiedOriginal = currentParticle;
102
103 currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere
104 targetParticle.SetSide( -1 ); // target always goes in backward hemisphere
105 G4bool incidentHasChanged = false;
106 G4bool targetHasChanged = false;
107 G4bool quasiElastic = false;
108 G4FastVector<G4ReactionProduct,GHADLISTSIZE> vec; // vec will contain the secondary particles
109 G4int vecLen = 0;
110 vec.Initialize( 0 );
111
112 const G4double cutOff = 0.1*MeV;
113 if( currentParticle.GetKineticEnergy() > cutOff )
114 Cascade( vec, vecLen,
115 originalIncident, currentParticle, targetParticle,
116 incidentHasChanged, targetHasChanged, quasiElastic );
117
118 CalculateMomenta( vec, vecLen,
119 originalIncident, originalTarget, modifiedOriginal,
120 targetNucleus, currentParticle, targetParticle,
121 incidentHasChanged, targetHasChanged, quasiElastic );
122
123 SetUpChange( vec, vecLen,
124 currentParticle, targetParticle,
125 incidentHasChanged );
126
127 delete originalTarget;
128
129 return &theParticleChange;
130 }
131
132 void
133 G4LEKaonPlusInelastic::Cascade(
134 G4FastVector<G4ReactionProduct,GHADLISTSIZE> &vec,
135 G4int &vecLen,
136 const G4HadProjectile *originalIncident,
137 G4ReactionProduct &currentParticle,
138 G4ReactionProduct &targetParticle,
139 G4bool &incidentHasChanged,
140 G4bool &targetHasChanged,
141 G4bool &quasiElastic )
142 {
143 // derived from original FORTRAN code CASKP by H. Fesefeldt (13-Sep-1987)
144 //
145 // K+ undergoes interaction with nucleon within a nucleus. Check if it is
146 // energetically possible to produce pions/kaons. In not, assume nuclear excitation
147 // occurs and input particle is degraded in energy. No other particles are produced.
148 // If reaction is possible, find the correct number of pions/protons/neutrons
149 // produced using an interpolation to multiplicity data. Replace some pions or
150 // protons/neutrons by kaons or strange baryons according to the average
151 // multiplicity per Inelastic reaction.
152 //
153 const G4double mOriginal = originalIncident->GetDefinition()->GetPDGMass();
154 const G4double etOriginal = originalIncident->GetTotalEnergy();
155 const G4double targetMass = targetParticle.GetMass();
156 G4double centerofmassEnergy = std::sqrt( mOriginal*mOriginal +
157 targetMass*targetMass +
158 2.0*targetMass*etOriginal );
159 G4double availableEnergy = centerofmassEnergy-(targetMass+mOriginal);
160 if( availableEnergy < G4PionPlus::PionPlus()->GetPDGMass() )
161 {
162 quasiElastic = true;
163 return;
164 }
165 static G4bool first = true;
166 const G4int numMul = 1200;
167 const G4int numSec = 60;
168 static G4double protmul[numMul], protnorm[numSec]; // proton constants
169 static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
170 // np = number of pi+, nm = number of pi-, nz = number of pi0
171 G4int nt=0, np=0, nm=0, nz=0;
172 const G4double c = 1.25;
173 const G4double b[] = { 0.70, 0.70 };
174 if( first ) // compute normalization constants, this will only be Done once
175 {
176 first = false;
177 G4int i;
178 for( i=0; i<numMul; ++i )protmul[i] = 0.0;
179 for( i=0; i<numSec; ++i )protnorm[i] = 0.0;
180 G4int counter = -1;
181 for( np=0; np<(numSec/3); ++np )
182 {
183 for( nm=std::max(0,np-2); nm<=np; ++nm )
184 {
185 for( nz=0; nz<numSec/3; ++nz )
186 {
187 if( ++counter < numMul )
188 {
189 nt = np+nm+nz;
190 if( nt > 0 )
191 {
192 protmul[counter] = Pmltpc(np,nm,nz,nt,b[0],c);
193 protnorm[nt-1] += protmul[counter];
194 }
195 }
196 }
197 }
198 }
199 for( i=0; i<numMul; ++i )neutmul[i] = 0.0;
200 for( i=0; i<numSec; ++i )neutnorm[i] = 0.0;
201 counter = -1;
202 for( np=0; np<numSec/3; ++np )
203 {
204 for( nm=std::max(0,np-1); nm<=(np+1); ++nm )
205 {
206 for( nz=0; nz<numSec/3; ++nz )
207 {
208 if( ++counter < numMul )
209 {
210 nt = np+nm+nz;
211 if( (nt>0) && (nt<=numSec) )
212 {
213 neutmul[counter] = Pmltpc(np,nm,nz,nt,b[1],c);
214 neutnorm[nt-1] += neutmul[counter];
215 }
216 }
217 }
218 }
219 }
220 for( i=0; i<numSec; ++i )
221 {
222 if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
223 if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
224 }
225 } // end of initialization
226
227 const G4double expxu = 82.; // upper bound for arg. of exp
228 const G4double expxl = -expxu; // lower bound for arg. of exp
229 G4ParticleDefinition *aKaonZS = G4KaonZeroShort::KaonZeroShort();
230 G4ParticleDefinition *aKaonZL = G4KaonZeroLong::KaonZeroLong();
231 G4ParticleDefinition *aNeutron = G4Neutron::Neutron();
232 G4ParticleDefinition *aProton = G4Proton::Proton();
233 G4int ieab = static_cast<G4int>(availableEnergy*5.0/GeV);
234 const G4double supp[] = {0.,0.4,0.55,0.65,0.75,0.82,0.86,0.90,0.94,0.98};
235 G4double test, w0, wp, wt, wm;
236 if( (availableEnergy < 2.0*GeV) && (G4UniformRand() >= supp[ieab]) )
237 {
238 // suppress high multiplicity events at low momentum
239 // only one pion will be produced
240
241 nm = np = nz = 0;
242 if( targetParticle.GetDefinition() == aProton )
243 {
244 test = std::exp( std::min( expxu, std::max( expxl, -sqr(1.0+b[0])/(2.0*c*c) ) ) );
245 w0 = test;
246 wp = test*2.0;
247 if( G4UniformRand() < w0/(w0+wp) )
248 nz = 1;
249 else
250 np = 1;
251 }
252 else // target is a neutron
253 {
254 test = std::exp( std::min( expxu, std::max( expxl, -sqr(1.0+b[1])/(2.0*c*c) ) ) );
255 w0 = test;
256 wp = test;
257 test = std::exp( std::min( expxu, std::max( expxl, -sqr(-1.0+b[1])/(2.0*c*c) ) ) );
258 wm = test;
259 wt = w0+wp+wm;
260 wp += w0;
261 G4double ran = G4UniformRand();
262 if( ran < w0/wt )
263 nz = 1;
264 else if( ran < wp/wt )
265 np = 1;
266 else
267 nm = 1;
268 }
269 }
270 else
271 {
272 G4double n, anpn;
273 GetNormalizationConstant( availableEnergy, n, anpn );
274 G4double ran = G4UniformRand();
275 G4double dum, excs = 0.0;
276 if( targetParticle.GetDefinition() == aProton )
277 {
278 G4int counter = -1;
279 for( np=0; (np<numSec/3) && (ran>=excs); ++np )
280 {
281 for( nm=std::max(0,np-2); (nm<=np) && (ran>=excs); ++nm )
282 {
283 for( nz=0; (nz<numSec/3) && (ran>=excs); ++nz )
284 {
285 if( ++counter < numMul )
286 {
287 nt = np+nm+nz;
288 if( nt > 0 )
289 {
290 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
291 dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
292 if( std::fabs(dum) < 1.0 )
293 {
294 if( test >= 1.0e-10 )excs += dum*test;
295 }
296 else
297 excs += dum*test;
298 }
299 }
300 }
301 }
302 }
303 if( ran >= excs )return; // 3 previous loops continued to the end
304 np--; nm--; nz--;
305 }
306 else // target must be a neutron
307 {
308 G4int counter = -1;
309 for( np=0; (np<numSec/3) && (ran>=excs); ++np )
310 {
311 for( nm=std::max(0,np-1); (nm<=(np+1)) && (ran>=excs); ++nm )
312 {
313 for( nz=0; (nz<numSec/3) && (ran>=excs); ++nz )
314 {
315 if( ++counter < numMul )
316 {
317 nt = np+nm+nz;
318 if( (nt>=1) && (nt<=numSec) )
319 {
320 test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
321 dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
322 if( std::fabs(dum) < 1.0 )
323 {
324 if( test >= 1.0e-10 )excs += dum*test;
325 }
326 else
327 excs += dum*test;
328 }
329 }
330 }
331 }
332 }
333 if( ran >= excs )return; // 3 previous loops continued to the end
334 np--; nm--; nz--;
335 }
336 }
337 if( targetParticle.GetDefinition() == aProton )
338 {
339 switch( np-nm )
340 {
341 case 1:
342 if( G4UniformRand() < 0.5 )
343 {
344 if( G4UniformRand() < 0.5 )
345 currentParticle.SetDefinitionAndUpdateE( aKaonZS );
346 else
347 currentParticle.SetDefinitionAndUpdateE( aKaonZL );
348 incidentHasChanged = true;
349 }
350 else
351 {
352 targetParticle.SetDefinitionAndUpdateE( aNeutron );
353 targetHasChanged = true;
354 }
355 break;
356 case 2:
357 if( G4UniformRand() < 0.5 )
358 currentParticle.SetDefinitionAndUpdateE( aKaonZS );
359 else
360 currentParticle.SetDefinitionAndUpdateE( aKaonZL );
361 incidentHasChanged = true;
362 targetParticle.SetDefinitionAndUpdateE( aNeutron );
363 incidentHasChanged = true;
364 targetHasChanged = true;
365 break;
366 default:
367 break;
368 }
369 }
370 else // target is a neutron
371 {
372 switch( np-nm )
373 {
374 case 0:
375 if( G4UniformRand() < 0.25 )
376 {
377 if( G4UniformRand() < 0.5 )
378 currentParticle.SetDefinitionAndUpdateE( aKaonZS );
379 else
380 currentParticle.SetDefinitionAndUpdateE( aKaonZL );
381 targetParticle.SetDefinitionAndUpdateE( aProton );
382 incidentHasChanged = true;
383 targetHasChanged = true;
384 }
385 break;
386 case 1:
387 if( G4UniformRand() < 0.5 )
388 currentParticle.SetDefinitionAndUpdateE( aKaonZS );
389 else
390 currentParticle.SetDefinitionAndUpdateE( aKaonZL );
391 incidentHasChanged = true;
392 break;
393 default: // assumes nm = np+1 so charge is conserved
394 targetParticle.SetDefinitionAndUpdateE( aProton );
395 targetHasChanged = true;
396 break;
397 }
398 }
399 SetUpPions( np, nm, nz, vec, vecLen );
400 return;
401 }
402
403 /* end of file */
404
Note: See TracBrowser for help on using the repository browser.