source: trunk/source/processes/hadronic/stopping/src/G4MuonMinusCaptureAtRest.cc @ 1337

Last change on this file since 1337 was 1337, checked in by garnier, 14 years ago

tag geant4.9.4 beta 1 + modifs locales
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26// $Id: G4MuonMinusCaptureAtRest.cc,v 1.54 2009/01/24 11:55:38 vnivanch Exp $
27// GEANT4 tag $Name: geant4-09-04-beta-01 $
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// 23/01/2009  V.Ivanchenko Add deregistration
41//
42//-----------------------------------------------------------------------------
43
44#include "G4MuonMinusCaptureAtRest.hh"
45#include "G4DynamicParticle.hh"
46#include "Randomize.hh"
47#include "G4He3.hh"
48#include "G4NeutrinoMu.hh"
49#include "G4Fragment.hh"
50#include "G4ReactionProductVector.hh"
51#include "G4Proton.hh"
52#include "G4PionPlus.hh"
53#include "G4GHEKinematicsVector.hh"
54#include "G4Fancy3DNucleus.hh"
55#include "G4ExcitationHandler.hh"
56#include "G4HadronicProcessStore.hh"
57
58//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
59
60G4MuonMinusCaptureAtRest::G4MuonMinusCaptureAtRest(const G4String& processName,
61                                                   G4ProcessType   aType ) :
62  G4VRestProcess (processName, aType), nCascade(0), targetZ(0), targetA(0), 
63  isInitialised(false)
64{
65  SetProcessSubType(fHadronAtRest);
66  Cascade    = new G4GHEKinematicsVector [17];
67  pSelector  = new G4StopElementSelector();
68  pEMCascade = new G4MuMinusCaptureCascade();
69  theN       = new G4Fancy3DNucleus();
70  theHandler = new G4ExcitationHandler();
71  G4HadronicProcessStore::Instance()->RegisterExtraProcess(this);
72}
73
74//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
75
76G4MuonMinusCaptureAtRest::~G4MuonMinusCaptureAtRest()
77{
78  G4HadronicProcessStore::Instance()->DeRegisterExtraProcess(this);
79  delete [] Cascade;
80  delete pSelector;
81  delete pEMCascade;
82  delete theN;
83  delete theHandler;
84}
85
86//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
87
88G4bool G4MuonMinusCaptureAtRest::IsApplicable(const G4ParticleDefinition& p)
89{
90  return ( &p == G4MuonMinus::MuonMinus() );
91}
92
93//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
94
95void G4MuonMinusCaptureAtRest::PreparePhysicsTable(const G4ParticleDefinition& p) 
96{
97  G4HadronicProcessStore::Instance()->RegisterParticleForExtraProcess(this, &p);
98}
99
100//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
101
102void G4MuonMinusCaptureAtRest::BuildPhysicsTable(const G4ParticleDefinition& p) 
103{
104  G4HadronicProcessStore::Instance()->PrintInfo(&p);
105}
106
107//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
108
109G4VParticleChange* G4MuonMinusCaptureAtRest::AtRestDoIt(const G4Track& track, 
110                                                        const G4Step&)
111{
112  //
113  // Handles MuonMinuss at rest; a MuonMinus can either create secondaries or
114  // do nothing (in which case it should be sent back to decay-handling
115  // section
116  //
117  aParticleChange.Initialize(track);
118
119  // select element and get Z,A.
120  G4Element* aEle = pSelector->GetElement(track.GetMaterial());
121  targetZ = aEle->GetZ();
122  targetA = G4double(G4int(aEle->GetN()+0.5)); 
123  G4int ni = 0;
124
125  G4IsotopeVector* isv = aEle->GetIsotopeVector();
126  if(isv) ni = isv->size();
127
128  if(ni == 1) {
129    targetA = G4double(aEle->GetIsotope(0)->GetN());
130  } else if(ni > 1) {
131    G4double* ab = aEle->GetRelativeAbundanceVector();
132    G4double y = G4UniformRand();
133    G4int j = -1;
134    ni--;
135    do {
136      j++;
137      y -= ab[j];
138    } while (y > 0.0 && j < ni);
139    targetA = G4double(aEle->GetIsotope(j)->GetN());
140  }
141 
142  // Do the electromagnetic cascade of the muon in the nuclear field.
143  nCascade   = 0;
144  targetMass = G4NucleiProperties::GetNuclearMass(targetA, targetZ);
145  nCascade   = pEMCascade->DoCascade(targetZ, targetMass, Cascade);
146
147  // Decide on Decay or Capture, and doit.
148  G4double lambdac  = pSelector->GetMuonCaptureRate(targetZ, targetA);
149  G4double lambdad  = pSelector->GetMuonDecayRate(targetZ, targetA);
150  G4double lambda   = lambdac + lambdad;
151
152  // ===  Throw for capture  time.
153
154  G4double tDelay = -std::log(G4UniformRand()) / lambda;
155 
156  G4ReactionProductVector * captureResult = 0;
157  G4int nEmSecondaries = nCascade;
158  G4int nSecondaries = nCascade;
159  /*
160  G4cout << "lambda= " << lambda << " lambdac= " << lambdac
161         << " nem= " << nEmSecondaries << G4endl;
162  */
163  if( G4UniformRand()*lambda > lambdac) 
164    pEMCascade->DoBoundMuonMinusDecay(targetZ, &nEmSecondaries, Cascade);
165  else 
166    captureResult = DoMuCapture();
167 
168  // fill the final state
169  if(captureResult) nSecondaries += captureResult->size();
170  else nSecondaries = nEmSecondaries;
171  //G4cout << " nsec= " << nSecondaries << " nem= " << nEmSecondaries << G4endl;
172
173  aParticleChange.SetNumberOfSecondaries( nSecondaries );
174
175  G4double globalTime = track.GetGlobalTime();
176  G4ThreeVector position = track.GetPosition();
177  // Store nuclear cascade
178  if(captureResult) {
179    G4int n = captureResult->size();
180    for ( G4int isec = 0; isec < n; isec++ ) {
181      G4ReactionProduct* aParticle = captureResult->operator[](isec);
182      G4DynamicParticle * aNewParticle = new G4DynamicParticle();
183      aNewParticle->SetDefinition( aParticle->GetDefinition() );
184      G4LorentzVector itV(aParticle->GetTotalEnergy(), aParticle->GetMomentum());
185      aNewParticle->SetMomentum(itV.vect());
186      G4double localtime = globalTime + tDelay + aParticle->GetTOF();
187      G4Track* aNewTrack = new G4Track( aNewParticle, localtime, position);
188      aNewTrack->SetTouchableHandle(track.GetTouchableHandle());
189      aParticleChange.AddSecondary( aNewTrack );
190      delete aParticle;
191    }
192    delete captureResult;
193  }
194 
195  // Store electromagnetic cascade
196
197  if(nEmSecondaries > 0) {
198
199    for ( G4int isec = 0; isec < nEmSecondaries; isec++ ) {
200      G4ParticleDefinition* pd = Cascade[isec].GetParticleDef();
201      G4double localtime = globalTime;
202      if(isec >= nCascade) localtime += tDelay;
203      if(pd) {
204        G4DynamicParticle* aNewParticle = new G4DynamicParticle;
205        aNewParticle->SetDefinition( pd );
206        aNewParticle->SetMomentum( Cascade[isec].GetMomentum() );
207
208        G4Track* aNewTrack = new G4Track( aNewParticle, localtime, position );
209        aNewTrack->SetTouchableHandle(track.GetTouchableHandle());
210        aParticleChange.AddSecondary( aNewTrack );
211      }
212    }
213  }
214
215  aParticleChange.ProposeLocalEnergyDeposit(0.0);
216  aParticleChange.ProposeTrackStatus(fStopAndKill); 
217
218  return &aParticleChange;
219}
220
221//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
222
223G4ReactionProductVector* G4MuonMinusCaptureAtRest::DoMuCapture()
224{
225  G4double mumass = G4MuonMinus::MuonMinus()->GetPDGMass();
226  G4double muBindingEnergy = pEMCascade->GetKShellEnergy(targetZ);
227  /*
228  G4cout << "G4MuonMinusCaptureAtRest::DoMuCapture called Emu= "
229         << muBindingEnergy << G4endl;
230  */
231  // Energy on K-shell
232  G4double muEnergy = mumass + muBindingEnergy;
233  G4double muMom = std::sqrt(muBindingEnergy*(muBindingEnergy + 2.0*mumass));
234  G4double availableEnergy = targetMass + mumass - muBindingEnergy;
235  G4LorentzVector momInitial(0.0,0.0,0.0,availableEnergy);
236  G4LorentzVector momResidual;
237
238  G4ThreeVector vmu = muMom*pEMCascade->GetRandomVec();
239  G4LorentzVector aMuMom(vmu, muEnergy);
240
241  G4double residualMass = 
242    G4NucleiProperties::GetNuclearMass(targetA, targetZ - 1.0);
243
244  G4ReactionProductVector* aPreResult = 0;
245  G4ReactionProduct* aNu = new G4ReactionProduct();
246  aNu->SetDefinition( G4NeutrinoMu::NeutrinoMu() );
247
248  G4int iz = G4int(targetZ);
249  G4int ia = G4int(targetA);
250
251  // proton as a target
252  if(iz <= 2) {
253
254    if(ia > 1) {
255      if(iz == 1 && ia == 2) { 
256        availableEnergy -= neutron_mass_c2;
257      } else if(iz == 1 && ia == 3) {
258        availableEnergy -= 2.0*neutron_mass_c2;
259      } else if(iz == 2) {
260        G4ParticleDefinition* pd = 0;
261        if(ia == 3) pd = G4Deuteron::Deuteron();
262        if(ia == 4) pd = G4Triton::Triton();
263        else 
264          pd = G4ParticleTable::GetParticleTable()->FindIon(1,ia-1,0,1);
265
266        //      G4cout << "Extra " << pd->GetParticleName() << G4endl;
267        availableEnergy -= pd->GetPDGMass();
268      }
269    }
270    //
271    //  Computation in assumption of CM collision of mu and nucleaon
272    // 
273    G4double Enu  = 0.5*(availableEnergy - 
274                         neutron_mass_c2*neutron_mass_c2/availableEnergy);
275
276    // make the nu, and transform to lab;
277    G4ThreeVector nu3Mom = Enu*pEMCascade->GetRandomVec();
278
279    G4ReactionProduct* aN = new G4ReactionProduct();
280    aN->SetDefinition( G4Neutron::Neutron() );
281    aN->SetTotalEnergy( availableEnergy - Enu );
282    aN->SetMomentum( -nu3Mom );
283
284    aNu->SetTotalEnergy( Enu );
285    aNu->SetMomentum( nu3Mom );
286    aPreResult = new G4ReactionProductVector();
287
288    aPreResult->push_back(aN ); 
289    aPreResult->push_back(aNu);
290
291    if(verboseLevel > 1)
292      G4cout << "DoMuCapture on H or He" 
293             <<" EkinN(MeV)= " << (availableEnergy - Enu - neutron_mass_c2)/MeV
294             <<" Enu(MeV)= "<<aNu->GetTotalEnergy()/MeV
295             <<" n= " << aPreResult->size()
296             <<G4endl;
297
298    return aPreResult;
299  }
300
301  // pick random proton inside nucleus
302  G4double eEx;
303  do {
304    theN->Init(targetA, targetZ); 
305    G4LorentzVector thePMom;
306    G4Nucleon * aNucleon = 0;
307    G4int theProtonCounter = G4int( targetZ * G4UniformRand() );
308    G4int counter = 0;
309    theN->StartLoop();
310
311    while( (aNucleon=theN->GetNextNucleon()) ) {
312
313      if( aNucleon->GetDefinition() == G4Proton::Proton() ) {
314        counter++;
315        if(counter == theProtonCounter) {
316          thePMom  = aNucleon->GetMomentum();
317          break;
318        }
319      }
320    }
321
322    // Get the nu momentum in the CMS
323    G4LorentzVector theCMS = thePMom + aMuMom;
324    G4ThreeVector bst = theCMS.boostVector();
325
326    G4double Ecms = theCMS.mag();
327    G4double Enu  = 0.5*(Ecms - neutron_mass_c2*neutron_mass_c2/Ecms);
328    eEx = 0.0;
329
330    if(Enu > 0.0) {
331      // make the nu, and transform to lab;
332      G4ThreeVector nu3Mom = Enu*pEMCascade->GetRandomVec();
333      G4LorentzVector nuMom(nu3Mom, Enu);
334
335      // nu in lab.
336      nuMom.boost(bst);
337      aNu->SetTotalEnergy( nuMom.e() );
338      aNu->SetMomentum( nuMom.vect() );
339   
340      // make residual
341      momResidual = momInitial - nuMom;
342
343      // Call pre-compound on the rest.
344      eEx = momResidual.mag();
345      if(verboseLevel > 1)
346        G4cout << "G4MuonMinusCaptureAtRest::DoMuCapture: " 
347               << " Eex(MeV)= " << (eEx-residualMass)/MeV
348               << " Enu(MeV)= "<<aNu->GetTotalEnergy()/MeV
349               <<G4endl;
350    }
351  } while(eEx <= residualMass);
352
353//  G4cout << "muonCapture : " << eEx << " " << residualMass
354//         << " A,Z= " << targetA << ", "<< targetZ
355//       << "  " << G4int(targetA) << ", " << G4int(targetZ) << G4endl;
356
357  //
358  // Start Deexcitation
359  //
360  G4ThreeVector fromBreit = momResidual.boostVector();
361  G4LorentzVector fscm(0.0,0.0,0.0, eEx);
362  G4Fragment anInitialState;
363  anInitialState.SetA(targetA);
364  anInitialState.SetZ(G4double(iz - 1));
365  anInitialState.SetNumberOfParticles(2);
366  anInitialState.SetNumberOfCharged(0);
367  anInitialState.SetNumberOfHoles(1);
368  anInitialState.SetMomentum(fscm);
369  aPreResult = theHandler->BreakItUp(anInitialState);
370
371  G4ReactionProductVector::iterator ires;
372  G4double eBal = availableEnergy - aNu->GetTotalEnergy();
373  for(ires=aPreResult->begin(); ires!=aPreResult->end(); ires++) {
374    G4LorentzVector itV((*ires)->GetTotalEnergy(), (*ires)->GetMomentum());
375    itV.boost(fromBreit);
376    (*ires)->SetTotalEnergy(itV.t());
377    (*ires)->SetMomentum(itV.vect());
378    eBal -= itV.t();
379  }
380  //
381  // fill neutrino into result
382  //
383  aPreResult->push_back(aNu);
384 
385  if(verboseLevel > 1)
386    G4cout << "DoMuCapture:  Nsec= " 
387           << aPreResult->size() << " Ebalance(MeV)= " << eBal/MeV
388           <<" E0(MeV)= " <<availableEnergy/MeV
389           <<" Mres(GeV)= " <<residualMass/GeV
390           <<G4endl;
391
392  return aPreResult;
393} 
394
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