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 | // Author: Christian V"olcker (Christian.Volcker@cern.ch), |
---|
27 | // |
---|
28 | // Creation date: November 1997 |
---|
29 | // |
---|
30 | // Testfile: ../G4KaonMinusAbsorptionAtRestTest.cc |
---|
31 | // |
---|
32 | // Modifications: |
---|
33 | // Maria Grazia Pia September 1998 |
---|
34 | // Various bug fixes, eliminated several memory leaks |
---|
35 | // |
---|
36 | // ------------------------------------------------------------------- |
---|
37 | |
---|
38 | |
---|
39 | #include "G4KaonMinusAbsorptionAtRest.hh" |
---|
40 | |
---|
41 | #include "G4StopDeexcitation.hh" |
---|
42 | #include "G4StopTheoDeexcitation.hh" |
---|
43 | #include "G4StopDeexcitationAlgorithm.hh" |
---|
44 | #include "G4ReactionKinematics.hh" |
---|
45 | #include "G4HadronicProcessStore.hh" |
---|
46 | |
---|
47 | G4KaonMinusAbsorptionAtRest::G4KaonMinusAbsorptionAtRest(const G4String& processName, |
---|
48 | G4ProcessType aType ) : |
---|
49 | G4VRestProcess (processName, aType) |
---|
50 | { |
---|
51 | if (verboseLevel>0) { |
---|
52 | G4cout << GetProcessName() << " is created "<< G4endl; |
---|
53 | } |
---|
54 | SetProcessSubType(fHadronAtRest); |
---|
55 | |
---|
56 | // see Cohn et al, PLB27(1968) 527; |
---|
57 | // Davis et al, PLB1(1967) 434; |
---|
58 | |
---|
59 | pionAbsorptionRate = 0.07; |
---|
60 | |
---|
61 | // see VanderVelde-Wilquet et al, Nuov.Cim.39A(1978)538; |
---|
62 | // see VanderVelde-Wilquet et al, Nuov.Cim.38A(1977)178; |
---|
63 | // see VanderVelde-Wilquet et al, Nucl.Phys.A241(1975)511; |
---|
64 | // primary production rates ( for absorption on Carbon) |
---|
65 | // .. other elements are extrapolated by the halo factor. |
---|
66 | |
---|
67 | rateLambdaZeroPiZero = 0.052; |
---|
68 | rateSigmaMinusPiPlus = 0.199; |
---|
69 | rateSigmaPlusPiMinus = 0.446; |
---|
70 | rateSigmaZeroPiZero = 0.303; |
---|
71 | rateLambdaZeroPiMinus = 0.568; |
---|
72 | rateSigmaZeroPiMinus = 0.216; |
---|
73 | rateSigmaMinusPiZero = 0.216; |
---|
74 | |
---|
75 | // for sigma- p -> lambda n |
---|
76 | // sigma+ n -> lambda p |
---|
77 | // sigma- n -> lambda |
---|
78 | // all values compatible with 0.55 same literature as above. |
---|
79 | |
---|
80 | sigmaPlusLambdaConversionRate = 0.55; |
---|
81 | sigmaMinusLambdaConversionRate = 0.55; |
---|
82 | sigmaZeroLambdaConversionRate = 0.55; |
---|
83 | |
---|
84 | G4HadronicProcessStore::Instance()->RegisterExtraProcess(this); |
---|
85 | } |
---|
86 | |
---|
87 | |
---|
88 | G4KaonMinusAbsorptionAtRest::~G4KaonMinusAbsorptionAtRest() |
---|
89 | { |
---|
90 | G4HadronicProcessStore::Instance()->DeRegisterExtraProcess(this); |
---|
91 | } |
---|
92 | |
---|
93 | void G4KaonMinusAbsorptionAtRest::PreparePhysicsTable(const G4ParticleDefinition& p) |
---|
94 | { |
---|
95 | G4HadronicProcessStore::Instance()->RegisterParticleForExtraProcess(this, &p); |
---|
96 | } |
---|
97 | |
---|
98 | void G4KaonMinusAbsorptionAtRest::BuildPhysicsTable(const G4ParticleDefinition& p) |
---|
99 | { |
---|
100 | G4HadronicProcessStore::Instance()->PrintInfo(&p); |
---|
101 | } |
---|
102 | |
---|
103 | G4VParticleChange* G4KaonMinusAbsorptionAtRest::AtRestDoIt |
---|
104 | (const G4Track& track, const G4Step& ) |
---|
105 | { |
---|
106 | stoppedHadron = track.GetDynamicParticle(); |
---|
107 | |
---|
108 | // Check applicability |
---|
109 | |
---|
110 | if (!IsApplicable(*(stoppedHadron->GetDefinition()))) |
---|
111 | { |
---|
112 | G4cerr <<"G4KaonMinusAbsorptionAtRest:ERROR, particle must be a Kaon!" <<G4endl; |
---|
113 | return 0; |
---|
114 | } |
---|
115 | |
---|
116 | G4Material* material; |
---|
117 | material = track.GetMaterial(); |
---|
118 | nucleus = 0; |
---|
119 | do |
---|
120 | { |
---|
121 | // Select the nucleus, get nucleon |
---|
122 | nucleus = new G4Nucleus(material); |
---|
123 | if (nucleus->GetN() < 1.5) |
---|
124 | { |
---|
125 | delete nucleus; |
---|
126 | nucleus = 0; |
---|
127 | } |
---|
128 | } while(nucleus == 0); |
---|
129 | |
---|
130 | G4double Z = nucleus->GetZ(); |
---|
131 | G4double A = nucleus->GetN(); |
---|
132 | |
---|
133 | // Do the interaction with the nucleon |
---|
134 | G4DynamicParticleVector* absorptionProducts = KaonNucleonReaction(); |
---|
135 | |
---|
136 | // Secondary interactions |
---|
137 | |
---|
138 | G4DynamicParticle* thePion; |
---|
139 | unsigned int i; |
---|
140 | for(i = 0; i < absorptionProducts->size(); i++) |
---|
141 | { |
---|
142 | thePion = (*absorptionProducts)[i]; |
---|
143 | if (thePion->GetDefinition() == G4PionMinus::PionMinus() |
---|
144 | || thePion->GetDefinition() == G4PionPlus::PionPlus() |
---|
145 | || thePion->GetDefinition() == G4PionZero::PionZero()) |
---|
146 | { |
---|
147 | if (AbsorbPionByNucleus(thePion)) |
---|
148 | { |
---|
149 | absorptionProducts->erase(absorptionProducts->begin()+i); |
---|
150 | i--; |
---|
151 | delete thePion; |
---|
152 | if (verboseLevel > 1) |
---|
153 | G4cout << "G4KaonMinusAbsorption::AtRestDoIt: Pion absorbed in Nucleus" |
---|
154 | << G4endl; |
---|
155 | } |
---|
156 | } |
---|
157 | } |
---|
158 | |
---|
159 | G4DynamicParticle* theSigma; |
---|
160 | G4DynamicParticle* theLambda; |
---|
161 | for (i = 0; i < absorptionProducts->size(); i++) |
---|
162 | { |
---|
163 | theSigma = (*absorptionProducts)[i]; |
---|
164 | if (theSigma->GetDefinition() == G4SigmaMinus::SigmaMinus() |
---|
165 | || theSigma->GetDefinition() == G4SigmaPlus::SigmaPlus() |
---|
166 | || theSigma->GetDefinition() == G4SigmaZero::SigmaZero()) |
---|
167 | { |
---|
168 | theLambda = SigmaLambdaConversion(theSigma); |
---|
169 | if (theLambda != 0){ |
---|
170 | absorptionProducts->erase(absorptionProducts->begin()+i); |
---|
171 | i--; |
---|
172 | delete theSigma; |
---|
173 | absorptionProducts->push_back(theLambda); |
---|
174 | |
---|
175 | if (verboseLevel > 1) |
---|
176 | G4cout << "G4KaonMinusAbsorption::AtRestDoIt: SigmaLambdaConversion Done" |
---|
177 | << G4endl; |
---|
178 | } |
---|
179 | } |
---|
180 | } |
---|
181 | |
---|
182 | // Nucleus deexcitation |
---|
183 | |
---|
184 | G4double productEnergy = 0.; |
---|
185 | G4ThreeVector pProducts(0.,0.,0.); |
---|
186 | |
---|
187 | unsigned int nAbsorptionProducts = 0; |
---|
188 | if (absorptionProducts != 0) nAbsorptionProducts = absorptionProducts->size(); |
---|
189 | |
---|
190 | for ( i = 0; i<nAbsorptionProducts; i++) |
---|
191 | { |
---|
192 | pProducts = pProducts + (*absorptionProducts)[i]->GetMomentum(); |
---|
193 | productEnergy += (*absorptionProducts)[i]->GetKineticEnergy(); |
---|
194 | } |
---|
195 | |
---|
196 | G4double newZ = nucleus->GetZ(); |
---|
197 | G4double newA = nucleus->GetN(); |
---|
198 | |
---|
199 | G4double bDiff = G4NucleiProperties::GetBindingEnergy(static_cast<G4int>(A),static_cast<G4int>(Z)) - |
---|
200 | G4NucleiProperties::GetBindingEnergy(static_cast<G4int>(newA), static_cast<G4int>(newZ)); |
---|
201 | |
---|
202 | G4double pNucleus = pProducts.mag(); |
---|
203 | |
---|
204 | G4StopDeexcitationAlgorithm* nucleusAlgorithm = new G4StopTheoDeexcitation(); |
---|
205 | G4StopDeexcitation stopDeexcitation(nucleusAlgorithm); |
---|
206 | |
---|
207 | nucleus->AddExcitationEnergy(bDiff); |
---|
208 | |
---|
209 | // returns excitation energy for the moment .. |
---|
210 | G4double energyDeposit = nucleus->GetEnergyDeposit(); |
---|
211 | if (verboseLevel>0) |
---|
212 | { |
---|
213 | G4cout << " -- KaonAtRest -- excitation = " |
---|
214 | << energyDeposit |
---|
215 | << ", pNucleus = " |
---|
216 | << pNucleus |
---|
217 | << ", A: " |
---|
218 | << A |
---|
219 | << ", " |
---|
220 | << newA |
---|
221 | << ", Z: " |
---|
222 | << Z |
---|
223 | << ", " |
---|
224 | << newZ |
---|
225 | << G4endl; |
---|
226 | } |
---|
227 | |
---|
228 | if (energyDeposit < 0.) |
---|
229 | { |
---|
230 | G4Exception("G4KaonMinusAbsorptionAtRest", "007", FatalException, |
---|
231 | "AtRestDoIt -- excitation energy < 0"); |
---|
232 | } |
---|
233 | delete nucleus; |
---|
234 | |
---|
235 | G4ReactionProductVector* fragmentationProducts = stopDeexcitation.DoBreakUp(newA,newZ,energyDeposit,pNucleus); |
---|
236 | |
---|
237 | unsigned int nFragmentationProducts = 0; |
---|
238 | if (fragmentationProducts != 0) nFragmentationProducts = fragmentationProducts->size(); |
---|
239 | |
---|
240 | //Initialize ParticleChange |
---|
241 | aParticleChange.Initialize(track); |
---|
242 | aParticleChange.SetNumberOfSecondaries(G4int(nAbsorptionProducts+nFragmentationProducts) ); |
---|
243 | |
---|
244 | // update List of alive particles. put energy deposit at the right place ... |
---|
245 | for (i = 0; i < nAbsorptionProducts; i++) |
---|
246 | {aParticleChange.AddSecondary((*absorptionProducts)[i]); } |
---|
247 | if (absorptionProducts != 0) delete absorptionProducts; |
---|
248 | |
---|
249 | // for (i = 0; i < nFragmentationProducts; i++) |
---|
250 | // { aParticleChange.AddSecondary(fragmentationProducts->at(i)); } |
---|
251 | for(i=0; i<nFragmentationProducts; i++) |
---|
252 | { |
---|
253 | G4DynamicParticle * aNew = |
---|
254 | new G4DynamicParticle((*fragmentationProducts)[i]->GetDefinition(), |
---|
255 | (*fragmentationProducts)[i]->GetTotalEnergy(), |
---|
256 | (*fragmentationProducts)[i]->GetMomentum()); |
---|
257 | G4double newTime = aParticleChange.GetGlobalTime((*fragmentationProducts)[i]->GetFormationTime()); |
---|
258 | aParticleChange.AddSecondary(aNew, newTime); |
---|
259 | delete (*fragmentationProducts)[i]; |
---|
260 | } |
---|
261 | if (fragmentationProducts != 0) delete fragmentationProducts; |
---|
262 | |
---|
263 | // finally ... |
---|
264 | aParticleChange.ProposeTrackStatus(fStopAndKill); // Kill the incident Kaon |
---|
265 | return &aParticleChange; |
---|
266 | } |
---|
267 | |
---|
268 | |
---|
269 | G4DynamicParticle G4KaonMinusAbsorptionAtRest::GetAbsorbingNucleon() |
---|
270 | { |
---|
271 | G4DynamicParticle aNucleon; |
---|
272 | |
---|
273 | // Get nucleon definition, based on Z,N of current Nucleus |
---|
274 | aNucleon.SetDefinition(SelectAbsorbingNucleon()); |
---|
275 | |
---|
276 | // Fermi momentum distribution in three dimensions |
---|
277 | G4ThreeVector pFermi = nucleus->GetFermiMomentum(); |
---|
278 | aNucleon.SetMomentum(pFermi); |
---|
279 | |
---|
280 | return aNucleon; |
---|
281 | } |
---|
282 | |
---|
283 | G4ParticleDefinition* G4KaonMinusAbsorptionAtRest::SelectAbsorbingNucleon() |
---|
284 | { |
---|
285 | // (Ch. Voelcker) extended from ReturnTargetParticle(): |
---|
286 | // Choose a proton or a neutron as the absorbing particle, |
---|
287 | // taking weight into account! |
---|
288 | // Update nucleon's atomic numbers. |
---|
289 | |
---|
290 | G4ParticleDefinition* absorbingParticleDef; |
---|
291 | |
---|
292 | G4double ranflat = G4UniformRand(); |
---|
293 | |
---|
294 | G4double myZ = nucleus->GetZ(); // number of protons |
---|
295 | G4double myN = nucleus->GetN(); // number of nucleons (not neutrons!!) |
---|
296 | |
---|
297 | // See VanderVelde-Wilquet et al, Nuov.Cim.39A(1978)538; |
---|
298 | G4double carbonRatioNP = 0.18; // (Rn/Rp)c, see page 544 |
---|
299 | |
---|
300 | G4double neutronProtonRatio = NeutronHaloFactor(myZ,myN)*carbonRatioNP*(myN-myZ)/myZ; |
---|
301 | G4double protonProbability = 1./(1.+neutronProtonRatio); |
---|
302 | |
---|
303 | if ( ranflat < protonProbability ) |
---|
304 | { |
---|
305 | absorbingParticleDef = G4Proton::Proton(); |
---|
306 | myZ-= 1.; |
---|
307 | } |
---|
308 | else |
---|
309 | { absorbingParticleDef = G4Neutron::Neutron(); } |
---|
310 | |
---|
311 | myN -= 1.; |
---|
312 | nucleus->SetParameters(myN,myZ); |
---|
313 | return absorbingParticleDef; |
---|
314 | } |
---|
315 | |
---|
316 | |
---|
317 | G4double G4KaonMinusAbsorptionAtRest::NeutronHaloFactor(G4double Z, G4double N) |
---|
318 | { |
---|
319 | // this function should take care of the probability for absorption |
---|
320 | // on neutrons, depending on number of protons Z and number of neutrons N-Z |
---|
321 | // parametrisation from fit to |
---|
322 | // VanderVelde-Wilquet et al, Nuov.Cim.39A(1978)538; |
---|
323 | // |
---|
324 | |
---|
325 | if (Z == 1.) return 1.389; // deuterium |
---|
326 | else if (Z == 2.) return 1.78; // helium |
---|
327 | else if (Z == 10.) return 0.66; // neon |
---|
328 | else |
---|
329 | return 0.6742+(N-Z)*0.06524; |
---|
330 | } |
---|
331 | |
---|
332 | |
---|
333 | G4DynamicParticleVector* G4KaonMinusAbsorptionAtRest::KaonNucleonReaction() |
---|
334 | { |
---|
335 | G4DynamicParticleVector* products = new G4DynamicParticleVector(); |
---|
336 | |
---|
337 | G4double ranflat = G4UniformRand(); |
---|
338 | G4double prob = 0; |
---|
339 | |
---|
340 | G4ParticleDefinition* producedBaryonDef; |
---|
341 | G4ParticleDefinition* producedMesonDef; |
---|
342 | |
---|
343 | G4double iniZ = nucleus->GetZ(); |
---|
344 | G4double iniA = nucleus->GetN(); |
---|
345 | |
---|
346 | G4DynamicParticle aNucleon = GetAbsorbingNucleon(); |
---|
347 | |
---|
348 | G4double nucleonMass; |
---|
349 | |
---|
350 | if (aNucleon.GetDefinition() == G4Proton::Proton()) |
---|
351 | { |
---|
352 | nucleonMass = proton_mass_c2+electron_mass_c2; |
---|
353 | if ( (prob += rateLambdaZeroPiZero) > ranflat) |
---|
354 | { // lambda pi0 |
---|
355 | producedBaryonDef = G4Lambda::Lambda(); |
---|
356 | producedMesonDef = G4PionZero::PionZero(); |
---|
357 | } |
---|
358 | else if ((prob += rateSigmaPlusPiMinus) > ranflat) |
---|
359 | { // sigma+ pi- |
---|
360 | producedBaryonDef = G4SigmaPlus::SigmaPlus(); |
---|
361 | producedMesonDef = G4PionMinus::PionMinus(); |
---|
362 | } |
---|
363 | else if ((prob += rateSigmaMinusPiPlus) > ranflat) |
---|
364 | { // sigma- pi+ |
---|
365 | producedBaryonDef = G4SigmaMinus::SigmaMinus(); |
---|
366 | producedMesonDef = G4PionPlus::PionPlus(); |
---|
367 | } |
---|
368 | else |
---|
369 | { // sigma0 pi0 |
---|
370 | producedBaryonDef = G4SigmaZero::SigmaZero(); |
---|
371 | producedMesonDef = G4PionZero::PionZero(); |
---|
372 | } |
---|
373 | } |
---|
374 | else if (aNucleon.GetDefinition() == G4Neutron::Neutron()) |
---|
375 | { |
---|
376 | nucleonMass = neutron_mass_c2; |
---|
377 | if ((prob += rateLambdaZeroPiMinus) > ranflat) |
---|
378 | { // lambda pi- |
---|
379 | producedBaryonDef = G4Lambda::Lambda(); |
---|
380 | producedMesonDef = G4PionMinus::PionMinus(); |
---|
381 | } |
---|
382 | else if ((prob += rateSigmaZeroPiMinus) > ranflat) |
---|
383 | { // sigma0 pi- |
---|
384 | producedBaryonDef = G4SigmaZero::SigmaZero(); |
---|
385 | producedMesonDef = G4PionMinus::PionMinus(); |
---|
386 | } |
---|
387 | else |
---|
388 | { // sigma- pi0 |
---|
389 | producedBaryonDef = G4SigmaMinus::SigmaMinus(); |
---|
390 | producedMesonDef = G4PionZero::PionZero(); |
---|
391 | } |
---|
392 | } |
---|
393 | else |
---|
394 | { |
---|
395 | if (verboseLevel>0) |
---|
396 | { |
---|
397 | G4cout |
---|
398 | << "G4KaonMinusAbsorption::KaonNucleonReaction: " |
---|
399 | << aNucleon.GetDefinition()->GetParticleName() |
---|
400 | << " is not a good nucleon - check G4Nucleus::ReturnTargetParticle()!" |
---|
401 | << G4endl; |
---|
402 | } |
---|
403 | return 0; |
---|
404 | } |
---|
405 | |
---|
406 | G4double newZ = nucleus->GetZ(); |
---|
407 | G4double newA = nucleus->GetN(); |
---|
408 | |
---|
409 | // Modify the Kaon mass to take nuclear binding energy into account |
---|
410 | // .. using mas formula .. |
---|
411 | // .. using mass table .. |
---|
412 | // equivalent to -'initialBindingEnergy+nucleus.GetBindingEnergy' ! |
---|
413 | |
---|
414 | G4double nucleonBindingEnergy = |
---|
415 | -G4NucleiProperties::GetBindingEnergy(static_cast<G4int>(iniA), static_cast<G4int>(iniZ) ) |
---|
416 | +G4NucleiProperties::GetBindingEnergy(static_cast<G4int>(newA), static_cast<G4int>(newZ) ); |
---|
417 | |
---|
418 | G4DynamicParticle modifiedHadron = (*stoppedHadron); |
---|
419 | modifiedHadron.SetMass(stoppedHadron->GetMass() + nucleonBindingEnergy); |
---|
420 | |
---|
421 | // Setup outgoing dynamic particles |
---|
422 | G4ThreeVector dummy(0.,0.,0.); |
---|
423 | G4DynamicParticle* producedBaryon = new G4DynamicParticle(producedBaryonDef,dummy); |
---|
424 | G4DynamicParticle* producedMeson = new G4DynamicParticle(producedMesonDef,dummy); |
---|
425 | |
---|
426 | // Produce the secondary particles in a twobody process: |
---|
427 | G4ReactionKinematics theReactionKinematics; |
---|
428 | theReactionKinematics.TwoBodyScattering( &modifiedHadron, &aNucleon, |
---|
429 | producedBaryon, producedMeson); |
---|
430 | |
---|
431 | products->push_back(producedBaryon); |
---|
432 | products->push_back(producedMeson); |
---|
433 | |
---|
434 | if (verboseLevel > 1) |
---|
435 | { |
---|
436 | G4cout |
---|
437 | << "G4KaonMinusAbsorption::KaonNucleonReaction: Number of primaries = " |
---|
438 | << products->size() |
---|
439 | << ": " <<producedMesonDef->GetParticleName() |
---|
440 | << ", " <<producedBaryonDef->GetParticleName() << G4endl; |
---|
441 | } |
---|
442 | |
---|
443 | return products; |
---|
444 | } |
---|
445 | |
---|
446 | |
---|
447 | G4bool G4KaonMinusAbsorptionAtRest::AbsorbPionByNucleus(G4DynamicParticle* aPion) |
---|
448 | { |
---|
449 | // Needs some more investigation! |
---|
450 | |
---|
451 | G4double ranflat = G4UniformRand(); |
---|
452 | |
---|
453 | if (ranflat < pionAbsorptionRate){ |
---|
454 | // Add pion energy to ExcitationEnergy and NucleusMomentum |
---|
455 | nucleus->AddExcitationEnergy(aPion->GetTotalEnergy()); |
---|
456 | nucleus->AddMomentum(aPion->GetMomentum()); |
---|
457 | } |
---|
458 | |
---|
459 | return (ranflat < pionAbsorptionRate); |
---|
460 | } |
---|
461 | |
---|
462 | G4DynamicParticle* G4KaonMinusAbsorptionAtRest::SigmaLambdaConversion(G4DynamicParticle* aSigma) |
---|
463 | { |
---|
464 | G4double ranflat = G4UniformRand(); |
---|
465 | G4double sigmaLambdaConversionRate; |
---|
466 | |
---|
467 | G4double A = nucleus->GetN(); |
---|
468 | G4double Z = nucleus->GetZ(); |
---|
469 | |
---|
470 | G4double newZ = Z; |
---|
471 | G4double nucleonMassDifference = 0; |
---|
472 | |
---|
473 | G4ParticleDefinition* inNucleonDef=NULL; |
---|
474 | G4ParticleDefinition* outNucleonDef=NULL; |
---|
475 | |
---|
476 | // Decide which sigma |
---|
477 | switch((int) aSigma->GetDefinition()->GetPDGCharge()) { |
---|
478 | |
---|
479 | case 1: |
---|
480 | sigmaLambdaConversionRate = sigmaPlusLambdaConversionRate; |
---|
481 | inNucleonDef = G4Neutron::Neutron(); |
---|
482 | outNucleonDef = G4Proton::Proton(); |
---|
483 | newZ = Z+1; |
---|
484 | nucleonMassDifference = neutron_mass_c2 - proton_mass_c2-electron_mass_c2; |
---|
485 | break; |
---|
486 | |
---|
487 | case -1: |
---|
488 | sigmaLambdaConversionRate = sigmaMinusLambdaConversionRate; |
---|
489 | inNucleonDef = G4Proton::Proton(); |
---|
490 | outNucleonDef = G4Neutron::Neutron(); |
---|
491 | newZ = Z-1; |
---|
492 | nucleonMassDifference = proton_mass_c2+electron_mass_c2 - neutron_mass_c2; |
---|
493 | break; |
---|
494 | |
---|
495 | case 0: |
---|
496 | sigmaLambdaConversionRate = sigmaZeroLambdaConversionRate; |
---|
497 | // The 'outgoing' nucleon is just virtual, to keep the energy-momentum |
---|
498 | // balance and will not appear in the ParticleChange. Therefore no need |
---|
499 | // choose between neutron and proton here! |
---|
500 | inNucleonDef = G4Neutron::Neutron(); |
---|
501 | outNucleonDef = G4Neutron::Neutron(); |
---|
502 | break; |
---|
503 | |
---|
504 | default: |
---|
505 | sigmaLambdaConversionRate = 0.; |
---|
506 | } |
---|
507 | |
---|
508 | if (ranflat >= sigmaLambdaConversionRate) return 0; |
---|
509 | |
---|
510 | G4ThreeVector dummy(0.,0.,0.); |
---|
511 | |
---|
512 | // Fermi momentum distribution in three dimensions |
---|
513 | G4ThreeVector momentum = nucleus->GetFermiMomentum(); |
---|
514 | |
---|
515 | G4ParticleDefinition* lambdaDef = G4Lambda::Lambda(); |
---|
516 | |
---|
517 | G4DynamicParticle inNucleon(inNucleonDef,momentum); |
---|
518 | G4DynamicParticle outNucleon(outNucleonDef,dummy); |
---|
519 | G4DynamicParticle* outLambda = new G4DynamicParticle(lambdaDef,dummy); |
---|
520 | |
---|
521 | G4ReactionKinematics theReactionKinematics; |
---|
522 | |
---|
523 | // Now do the twobody scattering |
---|
524 | theReactionKinematics.TwoBodyScattering(aSigma, &inNucleon, |
---|
525 | &outNucleon, outLambda); |
---|
526 | |
---|
527 | // Binding energy of nucleus has changed. This will change the |
---|
528 | // ExcitationEnergy. |
---|
529 | // .. using mass formula .. |
---|
530 | // .. using mass table .. |
---|
531 | // equivalent to -'initialBindingEnergy+nucleus.GetBindingEnergy' ! |
---|
532 | |
---|
533 | // Add energy and momentum to nucleus, change Z,A |
---|
534 | nucleus->AddExcitationEnergy(outNucleon.GetKineticEnergy()); |
---|
535 | nucleus->AddMomentum(outNucleon.GetMomentum()); |
---|
536 | nucleus->SetParameters(A,newZ); |
---|
537 | |
---|
538 | // The calling routine is responsible to delete the sigma!! |
---|
539 | return outLambda; |
---|
540 | } |
---|
541 | |
---|
542 | |
---|
543 | |
---|