source: trunk/source/processes/hadronic/stopping/src/G4MuonMinusCaptureAtRest.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// $Id: G4MuonMinusCaptureAtRest.cc,v 1.53 2008/10/02 20:57:52 dennis Exp $
27// GEANT4 tag $Name: geant4-09-02 $
28//
29// G4MuonMinusCaptureAtRest physics process
30// Larry Felawka (TRIUMF) and Art Olin (TRIUMF)
31// April 1998
32//---------------------------------------------------------------------
33//
34// Modifications:
35// 18/08/2000 V.Ivanchenko Update description
36// 12/12/2003 H.P.Wellisch Completly rewrite mu-nuclear part
37// 17/05/2006 V.Ivanchenko Cleanup
38// 15/11/2006 V.Ivanchenko Review and rewrite all kinematics
39// 24/01/2007 V.Ivanchenko Force to work with integer Z and A
40//
41//-----------------------------------------------------------------------------
42
43#include "G4MuonMinusCaptureAtRest.hh"
44#include "G4DynamicParticle.hh"
45#include "Randomize.hh"
46#include "G4He3.hh"
47#include "G4NeutrinoMu.hh"
48#include "G4Fragment.hh"
49#include "G4ReactionProductVector.hh"
50#include "G4Proton.hh"
51#include "G4PionPlus.hh"
52#include "G4GHEKinematicsVector.hh"
53#include "G4Fancy3DNucleus.hh"
54#include "G4ExcitationHandler.hh"
55#include "G4HadronicProcessStore.hh"
56
57//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
58
59G4MuonMinusCaptureAtRest::G4MuonMinusCaptureAtRest(const G4String& processName,
60 G4ProcessType aType ) :
61 G4VRestProcess (processName, aType), nCascade(0), targetZ(0), targetA(0),
62 isInitialised(false)
63{
64 SetProcessSubType(fHadronAtRest);
65 Cascade = new G4GHEKinematicsVector [17];
66 pSelector = new G4StopElementSelector();
67 pEMCascade = new G4MuMinusCaptureCascade();
68 theN = new G4Fancy3DNucleus();
69 theHandler = new G4ExcitationHandler();
70 G4HadronicProcessStore::Instance()->RegisterExtraProcess(this);
71}
72
73//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
74
75G4MuonMinusCaptureAtRest::~G4MuonMinusCaptureAtRest()
76{
77 delete [] Cascade;
78 delete pSelector;
79 delete pEMCascade;
80 delete theN;
81 delete theHandler;
82}
83
84//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
85
86G4bool G4MuonMinusCaptureAtRest::IsApplicable(const G4ParticleDefinition& p)
87{
88 return ( &p == G4MuonMinus::MuonMinus() );
89}
90
91//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
92
93void G4MuonMinusCaptureAtRest::PreparePhysicsTable(const G4ParticleDefinition& p)
94{
95 G4HadronicProcessStore::Instance()->RegisterParticleForExtraProcess(this, &p);
96}
97
98//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
99
100void G4MuonMinusCaptureAtRest::BuildPhysicsTable(const G4ParticleDefinition& p)
101{
102 G4HadronicProcessStore::Instance()->PrintInfo(&p);
103}
104
105//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
106
107G4VParticleChange* G4MuonMinusCaptureAtRest::AtRestDoIt(const G4Track& track,
108 const G4Step&)
109{
110 //
111 // Handles MuonMinuss at rest; a MuonMinus can either create secondaries or
112 // do nothing (in which case it should be sent back to decay-handling
113 // section
114 //
115 aParticleChange.Initialize(track);
116
117 // select element and get Z,A.
118 G4Element* aEle = pSelector->GetElement(track.GetMaterial());
119 targetZ = aEle->GetZ();
120 targetA = G4double(G4int(aEle->GetN()+0.5));
121 G4int ni = 0;
122
123 G4IsotopeVector* isv = aEle->GetIsotopeVector();
124 if(isv) ni = isv->size();
125
126 if(ni == 1) {
127 targetA = G4double(aEle->GetIsotope(0)->GetN());
128 } else if(ni > 1) {
129 G4double* ab = aEle->GetRelativeAbundanceVector();
130 G4double y = G4UniformRand();
131 G4int j = -1;
132 ni--;
133 do {
134 j++;
135 y -= ab[j];
136 } while (y > 0.0 && j < ni);
137 targetA = G4double(aEle->GetIsotope(j)->GetN());
138 }
139
140 // Do the electromagnetic cascade of the muon in the nuclear field.
141 nCascade = 0;
142 targetMass = G4NucleiProperties::GetNuclearMass(targetA, targetZ);
143 nCascade = pEMCascade->DoCascade(targetZ, targetMass, Cascade);
144
145 // Decide on Decay or Capture, and doit.
146 G4double lambdac = pSelector->GetMuonCaptureRate(targetZ, targetA);
147 G4double lambdad = pSelector->GetMuonDecayRate(targetZ, targetA);
148 G4double lambda = lambdac + lambdad;
149
150 // === Throw for capture time.
151
152 G4double tDelay = -std::log(G4UniformRand()) / lambda;
153
154 G4ReactionProductVector * captureResult = 0;
155 G4int nEmSecondaries = nCascade;
156 G4int nSecondaries = nCascade;
157 /*
158 G4cout << "lambda= " << lambda << " lambdac= " << lambdac
159 << " nem= " << nEmSecondaries << G4endl;
160 */
161 if( G4UniformRand()*lambda > lambdac)
162 pEMCascade->DoBoundMuonMinusDecay(targetZ, &nEmSecondaries, Cascade);
163 else
164 captureResult = DoMuCapture();
165
166 // fill the final state
167 if(captureResult) nSecondaries += captureResult->size();
168 else nSecondaries = nEmSecondaries;
169 //G4cout << " nsec= " << nSecondaries << " nem= " << nEmSecondaries << G4endl;
170
171 aParticleChange.SetNumberOfSecondaries( nSecondaries );
172
173 G4double globalTime = track.GetGlobalTime();
174 G4ThreeVector position = track.GetPosition();
175 // Store nuclear cascade
176 if(captureResult) {
177 G4int n = captureResult->size();
178 for ( G4int isec = 0; isec < n; isec++ ) {
179 G4ReactionProduct* aParticle = captureResult->operator[](isec);
180 G4DynamicParticle * aNewParticle = new G4DynamicParticle();
181 aNewParticle->SetDefinition( aParticle->GetDefinition() );
182 G4LorentzVector itV(aParticle->GetTotalEnergy(), aParticle->GetMomentum());
183 aNewParticle->SetMomentum(itV.vect());
184 G4double localtime = globalTime + tDelay + aParticle->GetTOF();
185 G4Track* aNewTrack = new G4Track( aNewParticle, localtime, position);
186 aNewTrack->SetTouchableHandle(track.GetTouchableHandle());
187 aParticleChange.AddSecondary( aNewTrack );
188 delete aParticle;
189 }
190 delete captureResult;
191 }
192
193 // Store electromagnetic cascade
194
195 if(nEmSecondaries > 0) {
196
197 for ( G4int isec = 0; isec < nEmSecondaries; isec++ ) {
198 G4ParticleDefinition* pd = Cascade[isec].GetParticleDef();
199 G4double localtime = globalTime;
200 if(isec >= nCascade) localtime += tDelay;
201 if(pd) {
202 G4DynamicParticle* aNewParticle = new G4DynamicParticle;
203 aNewParticle->SetDefinition( pd );
204 aNewParticle->SetMomentum( Cascade[isec].GetMomentum() );
205
206 G4Track* aNewTrack = new G4Track( aNewParticle, localtime, position );
207 aNewTrack->SetTouchableHandle(track.GetTouchableHandle());
208 aParticleChange.AddSecondary( aNewTrack );
209 }
210 }
211 }
212
213 aParticleChange.ProposeLocalEnergyDeposit(0.0);
214 aParticleChange.ProposeTrackStatus(fStopAndKill);
215
216 return &aParticleChange;
217}
218
219//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
220
221G4ReactionProductVector* G4MuonMinusCaptureAtRest::DoMuCapture()
222{
223 G4double mumass = G4MuonMinus::MuonMinus()->GetPDGMass();
224 G4double muBindingEnergy = pEMCascade->GetKShellEnergy(targetZ);
225 /*
226 G4cout << "G4MuonMinusCaptureAtRest::DoMuCapture called Emu= "
227 << muBindingEnergy << G4endl;
228 */
229 // Energy on K-shell
230 G4double muEnergy = mumass + muBindingEnergy;
231 G4double muMom = std::sqrt(muBindingEnergy*(muBindingEnergy + 2.0*mumass));
232 G4double availableEnergy = targetMass + mumass - muBindingEnergy;
233 G4LorentzVector momInitial(0.0,0.0,0.0,availableEnergy);
234 G4LorentzVector momResidual;
235
236 G4ThreeVector vmu = muMom*pEMCascade->GetRandomVec();
237 G4LorentzVector aMuMom(vmu, muEnergy);
238
239 G4double residualMass =
240 G4NucleiProperties::GetNuclearMass(targetA, targetZ - 1.0);
241
242 G4ReactionProductVector* aPreResult = 0;
243 G4ReactionProduct* aNu = new G4ReactionProduct();
244 aNu->SetDefinition( G4NeutrinoMu::NeutrinoMu() );
245
246 G4int iz = G4int(targetZ);
247 G4int ia = G4int(targetA);
248
249 // proton as a target
250 if(iz <= 2) {
251
252 if(ia > 1) {
253 if(iz == 1 && ia == 2) {
254 availableEnergy -= neutron_mass_c2;
255 } else if(iz == 1 && ia == 3) {
256 availableEnergy -= 2.0*neutron_mass_c2;
257 } else if(iz == 2) {
258 G4ParticleDefinition* pd = 0;
259 if(ia == 3) pd = G4Deuteron::Deuteron();
260 if(ia == 4) pd = G4Triton::Triton();
261 else
262 pd = G4ParticleTable::GetParticleTable()->FindIon(1,ia-1,0,1);
263
264 // G4cout << "Extra " << pd->GetParticleName() << G4endl;
265 availableEnergy -= pd->GetPDGMass();
266 }
267 }
268 //
269 // Computation in assumption of CM collision of mu and nucleaon
270 //
271 G4double Enu = 0.5*(availableEnergy -
272 neutron_mass_c2*neutron_mass_c2/availableEnergy);
273
274 // make the nu, and transform to lab;
275 G4ThreeVector nu3Mom = Enu*pEMCascade->GetRandomVec();
276
277 G4ReactionProduct* aN = new G4ReactionProduct();
278 aN->SetDefinition( G4Neutron::Neutron() );
279 aN->SetTotalEnergy( availableEnergy - Enu );
280 aN->SetMomentum( -nu3Mom );
281
282 aNu->SetTotalEnergy( Enu );
283 aNu->SetMomentum( nu3Mom );
284 aPreResult = new G4ReactionProductVector();
285
286 aPreResult->push_back(aN );
287 aPreResult->push_back(aNu);
288
289 if(verboseLevel > 1)
290 G4cout << "DoMuCapture on H or He"
291 <<" EkinN(MeV)= " << (availableEnergy - Enu - neutron_mass_c2)/MeV
292 <<" Enu(MeV)= "<<aNu->GetTotalEnergy()/MeV
293 <<" n= " << aPreResult->size()
294 <<G4endl;
295
296 return aPreResult;
297 }
298
299 // pick random proton inside nucleus
300 G4double eEx;
301 do {
302 theN->Init(targetA, targetZ);
303 G4LorentzVector thePMom;
304 G4Nucleon * aNucleon = 0;
305 G4int theProtonCounter = G4int( targetZ * G4UniformRand() );
306 G4int counter = 0;
307 theN->StartLoop();
308
309 while( (aNucleon=theN->GetNextNucleon()) ) {
310
311 if( aNucleon->GetDefinition() == G4Proton::Proton() ) {
312 counter++;
313 if(counter == theProtonCounter) {
314 thePMom = aNucleon->GetMomentum();
315 break;
316 }
317 }
318 }
319
320 // Get the nu momentum in the CMS
321 G4LorentzVector theCMS = thePMom + aMuMom;
322 G4ThreeVector bst = theCMS.boostVector();
323
324 G4double Ecms = theCMS.mag();
325 G4double Enu = 0.5*(Ecms - neutron_mass_c2*neutron_mass_c2/Ecms);
326 eEx = 0.0;
327
328 if(Enu > 0.0) {
329 // make the nu, and transform to lab;
330 G4ThreeVector nu3Mom = Enu*pEMCascade->GetRandomVec();
331 G4LorentzVector nuMom(nu3Mom, Enu);
332
333 // nu in lab.
334 nuMom.boost(bst);
335 aNu->SetTotalEnergy( nuMom.e() );
336 aNu->SetMomentum( nuMom.vect() );
337
338 // make residual
339 momResidual = momInitial - nuMom;
340
341 // Call pre-compound on the rest.
342 eEx = momResidual.mag();
343 if(verboseLevel > 1)
344 G4cout << "G4MuonMinusCaptureAtRest::DoMuCapture: "
345 << " Eex(MeV)= " << (eEx-residualMass)/MeV
346 << " Enu(MeV)= "<<aNu->GetTotalEnergy()/MeV
347 <<G4endl;
348 }
349 } while(eEx <= residualMass);
350
351// G4cout << "muonCapture : " << eEx << " " << residualMass
352// << " A,Z= " << targetA << ", "<< targetZ
353// << " " << G4int(targetA) << ", " << G4int(targetZ) << G4endl;
354
355 //
356 // Start Deexcitation
357 //
358 G4ThreeVector fromBreit = momResidual.boostVector();
359 G4LorentzVector fscm(0.0,0.0,0.0, eEx);
360 G4Fragment anInitialState;
361 anInitialState.SetA(targetA);
362 anInitialState.SetZ(G4double(iz - 1));
363 anInitialState.SetNumberOfParticles(2);
364 anInitialState.SetNumberOfCharged(0);
365 anInitialState.SetNumberOfHoles(1);
366 anInitialState.SetMomentum(fscm);
367 aPreResult = theHandler->BreakItUp(anInitialState);
368
369 G4ReactionProductVector::iterator ires;
370 G4double eBal = availableEnergy - aNu->GetTotalEnergy();
371 for(ires=aPreResult->begin(); ires!=aPreResult->end(); ires++) {
372 G4LorentzVector itV((*ires)->GetTotalEnergy(), (*ires)->GetMomentum());
373 itV.boost(fromBreit);
374 (*ires)->SetTotalEnergy(itV.t());
375 (*ires)->SetMomentum(itV.vect());
376 eBal -= itV.t();
377 }
378 //
379 // fill neutrino into result
380 //
381 aPreResult->push_back(aNu);
382
383 if(verboseLevel > 1)
384 G4cout << "DoMuCapture: Nsec= "
385 << aPreResult->size() << " Ebalance(MeV)= " << eBal/MeV
386 <<" E0(MeV)= " <<availableEnergy/MeV
387 <<" Mres(GeV)= " <<residualMass/GeV
388 <<G4endl;
389
390 return aPreResult;
391}
392
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