source: trunk/source/processes/hadronic/models/high_energy/src/G4HEPionMinusInelastic.cc@ 1350

Last change on this file since 1350 was 1347, checked in by garnier, 15 years ago

geant4 tag 9.4
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25//
26// $Id: G4HEPionMinusInelastic.cc,v 1.17 2010/11/29 05:44:44 dennis Exp $
27// GEANT4 tag $Name: geant4-09-04-ref-00 $
28//
29// 11-OCT-2007 F.W. Jones: fixed incorrect Imax (should be Imin) in
30// sampling of charge exchange.
31
32
33#include "globals.hh"
34#include "G4ios.hh"
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
39// like nuclear reactions, nuclear fission without any cascading and all
40// processes for 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 "G4HEPionMinusInelastic.hh"
46
47G4HadFinalState*
48G4HEPionMinusInelastic::ApplyYourself(const G4HadProjectile& aTrack,
49 G4Nucleus& targetNucleus)
50{
51 G4HEVector* pv = new G4HEVector[MAXPART];
52 const G4HadProjectile* aParticle = &aTrack;
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 G4int incidentCode = incidentParticle.getCode();
61 G4double incidentMass = incidentParticle.getMass();
62 G4double incidentTotalEnergy = incidentParticle.getEnergy();
63 G4double incidentTotalMomentum = incidentParticle.getTotalMomentum();
64 G4double incidentKineticEnergy = incidentTotalEnergy - incidentMass;
65
66 if (incidentKineticEnergy < 1.)
67 G4cout << "GHEPionMinusInelastic: incident energy < 1 GeV" << G4endl;
68
69 if (verboseLevel > 1) {
70 G4cout << "G4HEPionMinusInelastic::ApplyYourself" << G4endl;
71 G4cout << "incident particle " << incidentParticle.getName()
72 << "mass " << incidentMass
73 << "kinetic energy " << incidentKineticEnergy
74 << G4endl;
75 G4cout << "target material with (A,Z) = ("
76 << atomicWeight << "," << atomicNumber << ")" << G4endl;
77 }
78
79 G4double inelasticity = NuclearInelasticity(incidentKineticEnergy,
80 atomicWeight, atomicNumber);
81 if (verboseLevel > 1)
82 G4cout << "nuclear inelasticity = " << inelasticity << G4endl;
83
84 incidentKineticEnergy -= inelasticity;
85
86 G4double excitationEnergyGNP = 0.;
87 G4double excitationEnergyDTA = 0.;
88
89 G4double excitation = NuclearExcitation(incidentKineticEnergy,
90 atomicWeight, atomicNumber,
91 excitationEnergyGNP,
92 excitationEnergyDTA);
93 if (verboseLevel > 1)
94 G4cout << "nuclear excitation = " << excitation << excitationEnergyGNP
95 << excitationEnergyDTA << G4endl;
96
97 incidentKineticEnergy -= excitation;
98 incidentTotalEnergy = incidentKineticEnergy + incidentMass;
99 incidentTotalMomentum = std::sqrt( (incidentTotalEnergy-incidentMass)
100 *(incidentTotalEnergy+incidentMass));
101
102 G4HEVector targetParticle;
103
104 if (G4UniformRand() < atomicNumber/atomicWeight) {
105 targetParticle.setDefinition("Proton");
106 } else {
107 targetParticle.setDefinition("Neutron");
108 }
109
110 G4double targetMass = targetParticle.getMass();
111 G4double centerOfMassEnergy = std::sqrt(incidentMass*incidentMass
112 + targetMass*targetMass
113 + 2.0*targetMass*incidentTotalEnergy);
114 G4double availableEnergy = centerOfMassEnergy - targetMass - incidentMass;
115
116 // The value of the inElastic flag was originally defined in the Gheisha
117 // stand-alone code as follows:
118 // G4bool inElastic = InElasticCrossSectionInFirstInt
119 // (availableEnergy, incidentCode, incidentTotalMomentum);
120 // For unknown reasons, it was replaced by the following code in Geant
121
122 G4bool inElastic = true;
123 // if (G4UniformRand() < elasticCrossSection/totalCrossSection) inElastic = false;
124
125 vecLength = 0;
126
127 if (verboseLevel > 1)
128 G4cout << "ApplyYourself: CallFirstIntInCascade for particle "
129 << incidentCode << G4endl;
130
131 G4bool successful = false;
132
133 FirstIntInCasPionMinus(inElastic, availableEnergy, pv, vecLength,
134 incidentParticle, targetParticle);
135
136 if (verboseLevel > 1)
137 G4cout << "ApplyYourself::StrangeParticlePairProduction" << G4endl;
138
139 if ((vecLength > 0) && (availableEnergy > 1.))
140 StrangeParticlePairProduction(availableEnergy, centerOfMassEnergy,
141 pv, vecLength,
142 incidentParticle, targetParticle);
143
144 HighEnergyCascading(successful, pv, vecLength,
145 excitationEnergyGNP, excitationEnergyDTA,
146 incidentParticle, targetParticle,
147 atomicWeight, atomicNumber);
148 if (!successful)
149 HighEnergyClusterProduction(successful, pv, vecLength,
150 excitationEnergyGNP, excitationEnergyDTA,
151 incidentParticle, targetParticle,
152 atomicWeight, atomicNumber);
153 if (!successful)
154 MediumEnergyCascading(successful, pv, vecLength,
155 excitationEnergyGNP, excitationEnergyDTA,
156 incidentParticle, targetParticle,
157 atomicWeight, atomicNumber);
158
159 if (!successful)
160 MediumEnergyClusterProduction(successful, pv, vecLength,
161 excitationEnergyGNP, excitationEnergyDTA,
162 incidentParticle, targetParticle,
163 atomicWeight, atomicNumber);
164 if (!successful)
165 QuasiElasticScattering(successful, pv, vecLength,
166 excitationEnergyGNP, excitationEnergyDTA,
167 incidentParticle, targetParticle,
168 atomicWeight, atomicNumber);
169 if (!successful)
170 ElasticScattering(successful, pv, vecLength,
171 incidentParticle,
172 atomicWeight, atomicNumber);
173
174 if (!successful)
175 G4cout << "GHEInelasticInteraction::ApplyYourself fails to produce final state particles"
176 << G4endl;
177
178 FillParticleChange(pv, vecLength);
179 delete [] pv;
180 theParticleChange.SetStatusChange(stopAndKill);
181 return &theParticleChange;
182}
183
184
185void
186G4HEPionMinusInelastic::FirstIntInCasPionMinus(G4bool& inElastic,
187 const G4double availableEnergy,
188 G4HEVector pv[],
189 G4int& vecLen,
190 const G4HEVector& incidentParticle,
191 const G4HEVector& targetParticle)
192
193// Pion- undergoes interaction with nucleon within a nucleus. Check if it is
194// energetically possible to produce pions/kaons. In not, assume nuclear excitation
195// occurs and input particle is degraded in energy. No other particles are produced.
196// If reaction is possible, find the correct number of pions/protons/neutrons
197// produced using an interpolation to multiplicity data. Replace some pions or
198// protons/neutrons by kaons or strange baryons according to the average
199// multiplicity per inelastic reaction.
200{
201 static const G4double expxu = std::log(MAXFLOAT); // upper bound for arg. of exp
202 static const G4double expxl = -expxu; // lower bound for arg. of exp
203
204 static const G4double protb = 0.7;
205 static const G4double neutb = 0.7;
206 static const G4double c = 1.25;
207
208 static const G4int numMul = 1200;
209 static const G4int numSec = 60;
210
211 G4int protonCode = Proton.getCode();
212
213 G4int targetCode = targetParticle.getCode();
214 G4double incidentTotalMomentum = incidentParticle.getTotalMomentum();
215
216 static G4bool first = true;
217 static G4double protmul[numMul], protnorm[numSec]; // proton constants
218 static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
219
220 // misc. local variables
221 // np = number of pi+, nm = number of pi-, nz = number of pi0
222
223 G4int i, counter, nt, np, nm, nz;
224
225 if( first )
226 { // compute normalization constants, this will only be done once
227 first = false;
228 for( i=0; i<numMul; i++ )protmul[i] = 0.0;
229 for( i=0; i<numSec; i++ )protnorm[i] = 0.0;
230 counter = -1;
231 for( np=0; np<(numSec/3); np++ )
232 {
233 for( nm=Imax(0,np-1); nm<=(np+1); nm++ )
234 {
235 for( nz=0; nz<numSec/3; nz++ )
236 {
237 if( ++counter < numMul )
238 {
239 nt = np+nm+nz;
240 if( (nt>0) && (nt<=numSec) )
241 {
242 protmul[counter] =
243 pmltpc(np,nm,nz,nt,protb,c) ;
244 protnorm[nt-1] += protmul[counter];
245 }
246 }
247 }
248 }
249 }
250 for( i=0; i<numMul; i++ )neutmul[i] = 0.0;
251 for( i=0; i<numSec; i++ )neutnorm[i] = 0.0;
252 counter = -1;
253 for( np=0; np<numSec/3; np++ )
254 {
255 for( nm=np; nm<=(np+2); nm++ )
256 {
257 for( nz=0; nz<numSec/3; nz++ )
258 {
259 if( ++counter < numMul )
260 {
261 nt = np+nm+nz;
262 if( (nt>0) && (nt<=numSec) )
263 {
264 neutmul[counter] =
265 pmltpc(np,nm,nz,nt,neutb,c);
266 neutnorm[nt-1] += neutmul[counter];
267 }
268 }
269 }
270 }
271 }
272 for( i=0; i<numSec; i++ )
273 {
274 if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
275 if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
276 }
277 } // end of initialization
278
279
280 // initialize the first two places
281 // the same as beam and target
282 pv[0] = incidentParticle;
283 pv[1] = targetParticle;
284 vecLen = 2;
285
286 if (!inElastic || (availableEnergy <= PionPlus.getMass()))
287 return;
288
289
290 // inelastic scattering
291
292 np = 0, nm = 0, nz = 0;
293 G4double eab = availableEnergy;
294 G4int ieab = G4int( eab*5.0 );
295
296 G4double supp[] = {0., 0.4, 0.55, 0.65, 0.75, 0.82, 0.86, 0.90, 0.94, 0.98};
297 if( (ieab <= 9) && (G4UniformRand() >= supp[ieab]) )
298 {
299 // suppress high multiplicity events at low momentum
300 // only one additional pion will be produced
301 G4double cech[] = {1., 0.95, 0.79, 0.32, 0.19, 0.16, 0.14, 0.12, 0.10, 0.08};
302 G4int iplab = Imin(9, G4int( incidentTotalMomentum*5.));
303 if( G4UniformRand() < cech[iplab] )
304 {
305 if( targetCode == protonCode )
306 {
307 pv[0] = PionZero;
308 pv[1] = Neutron;
309 return;
310 }
311 else
312 {
313 return;
314 }
315 }
316
317 G4double w0, wp, wm, wt, ran;
318 if( targetCode == protonCode ) // target is a proton
319 {
320 w0 = - sqr(1.+protb)/(2.*c*c);
321 wp = w0 = std::exp(w0);
322 wm = - sqr(-1.+protb)/(2.*c*c);
323 wm = std::exp(wm);
324 wp *= 10.;
325 wt = w0+wp+wm;
326 wp = w0+wp;
327 ran = G4UniformRand();
328 if( ran < w0/wt )
329 { np = 0; nm = 0; nz = 1; }
330 else if ( ran < wp/wt )
331 { np = 1; nm = 0; nz = 0; }
332 else
333 { np = 0; nm = 1; nz = 0; }
334 }
335 else
336 { // target is a neutron
337 w0 = -sqr(1.+neutb)/(2.*c*c);
338 wm = -sqr(-1.+neutb)/(2.*c*c);
339 w0 = std::exp(w0);
340 wm = std::exp(wm);
341 if( G4UniformRand() < w0/(w0+wm) )
342 { np = 0; nm = 0; nz = 1; }
343 else
344 { np = 0; nm = 1; nz = 0; }
345 }
346 }
347 else
348 {
349 // number of total particles vs. centre of mass Energy - 2*proton mass
350
351 G4double aleab = std::log(availableEnergy);
352 G4double n = 3.62567+aleab*(0.665843+aleab*(0.336514
353 + aleab*(0.117712+0.0136912*aleab))) - 2.0;
354
355 // normalization constant for kno-distribution.
356 // calculate first the sum of all constants, check for numerical problems.
357 G4double test, dum, anpn = 0.0;
358
359 for (nt=1; nt<=numSec; nt++) {
360 test = std::exp( Amin( expxu, Amax( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
361 dum = pi*nt/(2.0*n*n);
362 if (std::fabs(dum) < 1.0) {
363 if( test >= 1.0e-10 )anpn += dum*test;
364 } else {
365 anpn += dum*test;
366 }
367 }
368
369 G4double ran = G4UniformRand();
370 G4double excs = 0.0;
371 if( targetCode == protonCode )
372 {
373 counter = -1;
374 for (np=0; np<numSec/3; np++) {
375 for (nm=Imax(0,np-1); nm<=(np+1); nm++) {
376 for (nz=0; nz<numSec/3; nz++) {
377 if (++counter < numMul) {
378 nt = np+nm+nz;
379 if ( (nt>0) && (nt<=numSec) ) {
380 test = std::exp( Amin( expxu, Amax( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
381 dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
382 if (std::fabs(dum) < 1.0) {
383 if( test >= 1.0e-10 )excs += dum*test;
384 } else {
385 excs += dum*test;
386 }
387 if (ran < excs) goto outOfLoop; //----------------------->
388 }
389 }
390 }
391 }
392 }
393
394 // 3 previous loops continued to the end
395 inElastic = false; // quasi-elastic scattering
396 return;
397 }
398 else
399 { // target must be a neutron
400 counter = -1;
401 for (np=0; np<numSec/3; np++) {
402 for (nm=np; nm<=(np+2); nm++) {
403 for (nz=0; nz<numSec/3; nz++) {
404 if (++counter < numMul) {
405 nt = np+nm+nz;
406 if ( (nt>=1) && (nt<=numSec) ) {
407 test = std::exp( Amin( expxu, Amax( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
408 dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
409 if (std::fabs(dum) < 1.0) {
410 if( test >= 1.0e-10 )excs += dum*test;
411 } else {
412 excs += dum*test;
413 }
414 if (ran < excs) goto outOfLoop; // ----------------->
415 }
416 }
417 }
418 }
419 }
420 // 3 previous loops continued to the end
421 inElastic = false; // quasi-elastic scattering.
422 return;
423 }
424 }
425 outOfLoop: // <-----------------------------------------------
426
427 if( targetCode == protonCode)
428 {
429 if( np == (1+nm))
430 {
431 pv[1] = Neutron;
432 }
433 else if (np == nm)
434 {
435 if( G4UniformRand() < 0.75)
436 {
437 }
438 else
439 {
440 pv[0] = PionZero;
441 pv[1] = Neutron;
442 }
443 }
444 else
445 {
446 pv[0] = PionZero;
447 }
448 }
449 else
450 {
451 if( np == (nm-1))
452 {
453 if( G4UniformRand() < 0.5)
454 {
455 pv[1] = Proton;
456 }
457 else
458 {
459 pv[0] = PionZero;
460 }
461 }
462 else if ( np == nm)
463 {
464 }
465 else
466 {
467 pv[0] = PionZero;
468 pv[1] = Proton;
469 }
470 }
471
472
473 nt = np + nm + nz;
474 while ( nt > 0)
475 {
476 G4double ran = G4UniformRand();
477 if ( ran < (G4double)np/nt)
478 {
479 if( np > 0 )
480 { pv[vecLen++] = PionPlus;
481 np--;
482 }
483 }
484 else if ( ran < (G4double)(np+nm)/nt)
485 {
486 if( nm > 0 )
487 {
488 pv[vecLen++] = PionMinus;
489 nm--;
490 }
491 }
492 else
493 {
494 if( nz > 0 )
495 {
496 pv[vecLen++] = PionZero;
497 nz--;
498 }
499 }
500 nt = np + nm + nz;
501 }
502 if (verboseLevel > 1)
503 {
504 G4cout << "Particles produced: " ;
505 G4cout << pv[0].getName() << " " ;
506 G4cout << pv[1].getName() << " " ;
507 for (i=2; i < vecLen; i++)
508 {
509 G4cout << pv[i].getName() << " " ;
510 }
511 G4cout << G4endl;
512 }
513 return;
514 }
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