source: trunk/source/processes/hadronic/models/high_energy/src/G4HEProtonInelastic.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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25//
26//
27// $Id: G4HEProtonInelastic.cc,v 1.14 2008/03/17 20:49:17 dennis Exp $
28// GEANT4 tag $Name: geant4-09-02 $
29//
30//
31
32#include "globals.hh"
33#include "G4ios.hh"
34
35//
36// G4 Process: Gheisha High Energy Collision model.
37// This includes the high energy cascading model, the two-body-resonance model
38// and the low energy two-body model. Not included are the low energy stuff like
39// nuclear reactions, nuclear fission without any cascading and all processes for
40// particles at rest.
41// First work done by J.L.Chuma and F.W.Jones, TRIUMF, June 96.
42// H. Fesefeldt, RWTH-Aachen, 23-October-1996
43// Last modified: 29-July-1998.
44
45#include "G4HEProtonInelastic.hh"
46
47G4HadFinalState * G4HEProtonInelastic::
48ApplyYourself( const G4HadProjectile &aTrack, G4Nucleus &targetNucleus )
49 {
50 G4HEVector * pv = new G4HEVector[MAXPART];
51 const G4HadProjectile *aParticle = &aTrack;
52// G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle();
53 const G4double A = targetNucleus.GetN();
54 const G4double Z = targetNucleus.GetZ();
55 G4HEVector incidentParticle(aParticle);
56
57 G4double atomicNumber = Z;
58 G4double atomicWeight = A;
59
60 if(verboseLevel > 1)
61 G4cout << "Z , A = " << atomicNumber << " " << atomicWeight << G4endl;
62
63 G4int incidentCode = incidentParticle.getCode();
64 G4double incidentMass = incidentParticle.getMass();
65 G4double incidentTotalEnergy = incidentParticle.getEnergy();
66 G4double incidentTotalMomentum = incidentParticle.getTotalMomentum();
67 G4double incidentKineticEnergy = incidentParticle.getKineticEnergy();
68
69 if(incidentKineticEnergy < 1.)
70 {
71 G4cout << "GHEProtonInelastic: incident energy < 1 GeV" << G4endl;
72 }
73 if(verboseLevel > 1)
74 {
75 G4cout << "G4HEProtonInelastic::ApplyYourself" << G4endl;
76 G4cout << "incident particle " << incidentParticle.getName() << " "
77 << "mass " << incidentMass << " "
78 << "kinetic energy " << incidentKineticEnergy
79 << G4endl;
80 G4cout << "target material with (A,Z) = ("
81 << atomicWeight << "," << atomicNumber << ")" << G4endl;
82 }
83
84 G4double inelasticity = NuclearInelasticity(incidentKineticEnergy,
85 atomicWeight, atomicNumber);
86 if(verboseLevel > 1)
87 G4cout << "nuclear inelasticity = " << inelasticity << G4endl;
88
89 incidentKineticEnergy -= inelasticity;
90
91 G4double excitationEnergyGNP = 0.;
92 G4double excitationEnergyDTA = 0.;
93
94 G4double excitation = NuclearExcitation(incidentKineticEnergy,
95 atomicWeight, atomicNumber,
96 excitationEnergyGNP,
97 excitationEnergyDTA);
98
99 if(verboseLevel > 1)
100 G4cout << "nuclear excitation = " << excitation << " " << excitationEnergyGNP << " "
101 << excitationEnergyDTA << G4endl;
102
103
104 incidentKineticEnergy -= excitation;
105 incidentTotalEnergy = incidentKineticEnergy + incidentMass;
106 incidentTotalMomentum = std::sqrt( (incidentTotalEnergy-incidentMass)
107 *(incidentTotalEnergy+incidentMass));
108
109
110 G4HEVector targetParticle;
111 if(G4UniformRand() < atomicNumber/atomicWeight)
112 {
113 targetParticle.setDefinition("Proton");
114 }
115 else
116 {
117 targetParticle.setDefinition("Neutron");
118 }
119
120 G4double targetMass = targetParticle.getMass();
121 G4double centerOfMassEnergy = std::sqrt( incidentMass*incidentMass + targetMass*targetMass
122 + 2.0*targetMass*incidentTotalEnergy);
123 G4double availableEnergy = centerOfMassEnergy - targetMass - incidentMass;
124
125 // this was the meaning of inElastic in the
126 // original Gheisha stand-alone version.
127// G4bool inElastic = InElasticCrossSectionInFirstInt
128// (availableEnergy, incidentCode, incidentTotalMomentum);
129 // by unknown reasons, it has been replaced
130 // to the following code in Geant???
131 G4bool inElastic = true;
132// if (G4UniformRand() < elasticCrossSection/totalCrossSection) inElastic = false;
133
134 vecLength = 0;
135
136 if(verboseLevel > 1)
137 G4cout << "ApplyYourself: CallFirstIntInCascade for particle "
138 << incidentCode << G4endl;
139
140 G4bool successful = false;
141
142 if(inElastic || (!inElastic && atomicWeight < 1.5))
143 {
144 FirstIntInCasProton(inElastic, availableEnergy, pv, vecLength,
145 incidentParticle, targetParticle, atomicWeight);
146
147 if(verboseLevel > 1)
148 G4cout << "ApplyYourself::StrangeParticlePairProduction" << G4endl;
149
150
151 if ((vecLength > 0) && (availableEnergy > 1.))
152 StrangeParticlePairProduction( availableEnergy, centerOfMassEnergy,
153 pv, vecLength,
154 incidentParticle, targetParticle);
155 HighEnergyCascading( successful, pv, vecLength,
156 excitationEnergyGNP, excitationEnergyDTA,
157 incidentParticle, targetParticle,
158 atomicWeight, atomicNumber);
159 if (!successful)
160 HighEnergyClusterProduction( successful, pv, vecLength,
161 excitationEnergyGNP, excitationEnergyDTA,
162 incidentParticle, targetParticle,
163 atomicWeight, atomicNumber);
164 if (!successful)
165 MediumEnergyCascading( successful, pv, vecLength,
166 excitationEnergyGNP, excitationEnergyDTA,
167 incidentParticle, targetParticle,
168 atomicWeight, atomicNumber);
169
170 if (!successful)
171 MediumEnergyClusterProduction( successful, pv, vecLength,
172 excitationEnergyGNP, excitationEnergyDTA,
173 incidentParticle, targetParticle,
174 atomicWeight, atomicNumber);
175 if (!successful)
176 QuasiElasticScattering( successful, pv, vecLength,
177 excitationEnergyGNP, excitationEnergyDTA,
178 incidentParticle, targetParticle,
179 atomicWeight, atomicNumber);
180 }
181 if (!successful)
182 {
183 ElasticScattering( successful, pv, vecLength,
184 incidentParticle,
185 atomicWeight, atomicNumber);
186 }
187
188 if (!successful)
189 {
190 G4cout << "GHEInelasticInteraction::ApplyYourself fails to produce final state particles" << G4endl;
191 }
192 FillParticleChange(pv, vecLength);
193 delete [] pv;
194 theParticleChange.SetStatusChange(stopAndKill);
195 return & theParticleChange;
196 }
197
198void
199G4HEProtonInelastic::FirstIntInCasProton( G4bool &inElastic,
200 const G4double availableEnergy,
201 G4HEVector pv[],
202 G4int &vecLen,
203 G4HEVector incidentParticle,
204 G4HEVector targetParticle,
205 const G4double atomicWeight)
206
207// Proton undergoes interaction with nucleon within a nucleus. Check if it is
208// energetically possible to produce pions/kaons. In not, assume nuclear excitation
209// occurs and input particle is degraded in energy. No other particles are produced.
210// If reaction is possible, find the correct number of pions/protons/neutrons
211// produced using an interpolation to multiplicity data. Replace some pions or
212// protons/neutrons by kaons or strange baryons according to the average
213// multiplicity per inelastic reaction.
214
215 {
216 static const G4double expxu = std::log(MAXFLOAT); // upper bound for arg. of exp
217 static const G4double expxl = -expxu; // lower bound for arg. of exp
218
219 static const G4double protb = 0.7;
220 static const G4double neutb = 0.35;
221 static const G4double c = 1.25;
222
223 static const G4int numMul = 1200;
224 static const G4int numSec = 60;
225
226 G4int neutronCode = Neutron.getCode();
227 G4int protonCode = Proton.getCode();
228 G4double pionMass = PionPlus.getMass();
229
230 G4int targetCode = targetParticle.getCode();
231// G4double incidentMass = incidentParticle.getMass();
232// G4double incidentEnergy = incidentParticle.getEnergy();
233 G4double incidentTotalMomentum = incidentParticle.getTotalMomentum();
234
235 static G4bool first = true;
236 static G4double protmul[numMul], protnorm[numSec]; // proton constants
237 static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
238
239 // misc. local variables
240 // np = number of pi+, nm = number of pi-, nz = number of pi0
241
242 G4int i, counter, nt, np, nm, nz;
243
244 if( first )
245 { // compute normalization constants, this will only be done once
246 first = false;
247 for( i=0; i<numMul; i++ )protmul[i] = 0.0;
248 for( i=0; i<numSec; i++ )protnorm[i] = 0.0;
249 counter = -1;
250 for( np=0; np<(numSec/3); np++ )
251 {
252 for( nm=Imax(0,np-2); nm<=np; nm++ )
253 {
254 for( nz=0; nz<numSec/3; nz++ )
255 {
256 if( ++counter < numMul )
257 {
258 nt = np+nm+nz;
259 if( (nt>0) && (nt<=numSec) )
260 {
261 protmul[counter] = pmltpc(np,nm,nz,nt,protb,c)
262 /(Factorial(2-np+nm)*Factorial(np-nm)) ;
263 protnorm[nt-1] += protmul[counter];
264 }
265 }
266 }
267 }
268 }
269 for( i=0; i<numMul; i++ )neutmul[i] = 0.0;
270 for( i=0; i<numSec; i++ )neutnorm[i] = 0.0;
271 counter = -1;
272 for( np=0; np<numSec/3; np++ )
273 {
274 for( nm=Imax(0,np-1); nm<=(np+1); nm++ )
275 {
276 for( nz=0; nz<numSec/3; nz++ )
277 {
278 if( ++counter < numMul )
279 {
280 nt = np+nm+nz;
281 if( (nt>0) && (nt<=numSec) )
282 {
283 neutmul[counter] = pmltpc(np,nm,nz,nt,neutb,c)
284 /(Factorial(1-np+nm)*Factorial(1+np-nm));
285 neutnorm[nt-1] += neutmul[counter];
286 }
287 }
288 }
289 }
290 }
291 for( i=0; i<numSec; i++ )
292 {
293 if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
294 if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
295 }
296 } // end of initialization
297
298
299 // initialize the first two places
300 // the same as beam and target
301 pv[0] = incidentParticle;
302 pv[1] = targetParticle;
303 vecLen = 2;
304
305 if( !inElastic )
306 { // quasi-elastic scattering, no pions produced
307 if( targetCode == neutronCode )
308 {
309 G4double cech[] = {0.50, 0.45, 0.40, 0.35, 0.30, 0.25, 0.06, 0.04, 0.005, 0.};
310 G4int iplab = G4int( Amin( 9.0, incidentTotalMomentum*2.5 ) );
311 if( G4UniformRand() < cech[iplab]/std::pow(atomicWeight,0.42) )
312 { // charge exchange pi+ n -> pi0 p
313 pv[0] = PionZero;
314 pv[1] = Proton;
315 }
316 }
317 return;
318 }
319 else if (availableEnergy <= pionMass)
320 return;
321
322 // inelastic scattering
323
324 np = 0, nm = 0, nz = 0;
325 G4double eab = availableEnergy;
326 G4int ieab = G4int( eab*5.0 );
327
328 G4double supp[] = {0., 0.4, 0.55, 0.65, 0.75, 0.82, 0.86, 0.90, 0.94, 0.98};
329 if( (ieab <= 9) && (G4UniformRand() >= supp[ieab]) )
330 {
331 // suppress high multiplicity events at low momentum
332 // only one additional pion will be produced
333 G4double w0, wp, wm, wt, ran;
334 if( targetCode == protonCode ) // target is a proton
335 {
336 w0 = - sqr(1.+protb)/(2.*c*c);
337 wp = w0 = std::exp(w0);
338 if( G4UniformRand() < w0/(w0+wp) )
339 { np = 0; nm = 0; nz = 1; }
340 else
341 { np = 1; nm = 0; nz = 0; }
342 }
343 else
344 { // target is a neutron
345 w0 = -sqr(1.+neutb)/(2.*c*c);
346 w0 = std::exp(w0);
347 wp = w0/2.;
348 wm = -sqr(-1.+neutb)/(2.*c*c);
349 wm = std::exp(wm)/2.;
350 wt = w0+wp+wm;
351 wp = w0+wp;
352 ran = G4UniformRand();
353 if( ran < w0/wt)
354 { np = 0; nm = 0; nz = 1; }
355 else if( ran < wp/wt)
356 { np = 1; nm = 0; nz = 0; }
357 else
358 { np = 0; nm = 1; nz = 0; }
359 }
360 }
361 else
362 {
363 // number of total particles vs. centre of mass Energy - 2*proton mass
364
365 G4double aleab = std::log(availableEnergy);
366 G4double n = 3.62567+aleab*(0.665843+aleab*(0.336514
367 + aleab*(0.117712+0.0136912*aleab))) - 2.0;
368
369 // normalization constant for kno-distribution.
370 // calculate first the sum of all constants, check for numerical problems.
371 G4double test, dum, anpn = 0.0;
372
373 for (nt=1; nt<=numSec; nt++) {
374 test = std::exp( Amin( expxu, Amax( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
375 dum = pi*nt/(2.0*n*n);
376 if (std::fabs(dum) < 1.0) {
377 if( test >= 1.0e-10 )anpn += dum*test;
378 } else {
379 anpn += dum*test;
380 }
381 }
382
383 G4double ran = G4UniformRand();
384 G4double excs = 0.0;
385 if( targetCode == protonCode )
386 {
387 counter = -1;
388 for (np=0; np<numSec/3; np++) {
389 for (nm=Imax(0,np-2); nm<=np; nm++) {
390 for (nz=0; nz<numSec/3; nz++) {
391 if (++counter < numMul) {
392 nt = np+nm+nz;
393 if ( (nt>0) && (nt<=numSec) ) {
394 test = std::exp( Amin( expxu, Amax( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
395 dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
396 if (std::fabs(dum) < 1.0) {
397 if( test >= 1.0e-10 )excs += dum*test;
398 } else {
399 excs += dum*test;
400 }
401 if (ran < excs) goto outOfLoop; //------------------>
402 }
403 }
404 }
405 }
406 }
407
408 // 3 previous loops continued to the end
409 inElastic = false; // quasi-elastic scattering
410 return;
411 }
412 else
413 { // target must be a neutron
414 counter = -1;
415 for (np=0; np<numSec/3; np++) {
416 for (nm=Imax(0,np-1); nm<=(np+1); nm++) {
417 for (nz=0; nz<numSec/3; nz++) {
418 if (++counter < numMul) {
419 nt = np+nm+nz;
420 if ( (nt>=1) && (nt<=numSec) ) {
421 test = std::exp( Amin( expxu, Amax( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
422 dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
423 if (std::fabs(dum) < 1.0) {
424 if( test >= 1.0e-10 )excs += dum*test;
425 } else {
426 excs += dum*test;
427 }
428 if (ran < excs) goto outOfLoop; // ------------->
429 }
430 }
431 }
432 }
433 }
434 // 3 previous loops continued to the end
435 inElastic = false; // quasi-elastic scattering.
436 return;
437 }
438 }
439 outOfLoop: // <-----------------------------------------------
440
441 if( targetCode == protonCode)
442 {
443 if( np == nm)
444 {
445 }
446 else if (np == (1+nm))
447 {
448 if( G4UniformRand() < 0.5)
449 {
450 pv[1] = Neutron;
451 }
452 else
453 {
454 pv[0] = Neutron;
455 }
456 }
457 else
458 {
459 pv[0] = Neutron;
460 pv[1] = Neutron;
461 }
462 }
463 else
464 {
465 if( np == nm)
466 {
467 if( G4UniformRand() < 0.25)
468 {
469 pv[0] = Neutron;
470 pv[1] = Proton;
471 }
472 else
473 {
474 }
475 }
476 else if ( np == (1+nm))
477 {
478 pv[0] = Neutron;
479 }
480 else
481 {
482 pv[1] = Proton;
483 }
484 }
485
486
487 nt = np + nm + nz;
488 while ( nt > 0)
489 {
490 G4double ran = G4UniformRand();
491 if ( ran < (G4double)np/nt)
492 {
493 if( np > 0 )
494 { pv[vecLen++] = PionPlus;
495 np--;
496 }
497 }
498 else if ( ran < (G4double)(np+nm)/nt)
499 {
500 if( nm > 0 )
501 {
502 pv[vecLen++] = PionMinus;
503 nm--;
504 }
505 }
506 else
507 {
508 if( nz > 0 )
509 {
510 pv[vecLen++] = PionZero;
511 nz--;
512 }
513 }
514 nt = np + nm + nz;
515 }
516 if (verboseLevel > 1)
517 {
518 G4cout << "Particles produced: " ;
519 G4cout << pv[0].getName() << " " ;
520 G4cout << pv[1].getName() << " " ;
521 for (i=2; i < vecLen; i++)
522 {
523 G4cout << pv[i].getName() << " " ;
524 }
525 G4cout << G4endl;
526 }
527 return;
528 }
529
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