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G4EvaporationChannel.cc
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26 // $Id: G4EvaporationChannel.cc 100690 2016-10-31 11:25:43Z gcosmo $
27 //
28 //J.M. Quesada (August2008). Based on:
29 //
30 // Hadronic Process: Nuclear De-excitations
31 // by V. Lara (Oct 1998)
32 //
33 // Modified:
34 // 03-09-2008 J.M. Quesada for external choice of inverse cross section option
35 // 06-09-2008 J.M. Quesada Also external choices have been added for superimposed
36 // Coulomb barrier (if useSICB is set true, by default is false)
37 // 17-11-2010 V.Ivanchenko in constructor replace G4VEmissionProbability by
38 // G4EvaporationProbability and do not new and delete probability
39 // object at each call; use G4Pow
40 
41 #include "G4EvaporationChannel.hh"
42 #include "G4PairingCorrection.hh"
43 #include "G4NucleiProperties.hh"
44 #include "G4Pow.hh"
45 #include "G4Log.hh"
46 #include "G4Exp.hh"
47 #include "G4PhysicalConstants.hh"
48 #include "G4SystemOfUnits.hh"
49 #include "Randomize.hh"
50 #include "G4RandomDirection.hh"
51 #include "G4Alpha.hh"
52 
54  const G4String & aName,
56  G4VCoulombBarrier* barrier):
57  G4VEvaporationChannel(aName),
58  theA(anA),
59  theZ(aZ),
60  theProbability(aprob),
61  theCoulombBarrier(barrier)
62 {
63  ResA = ResZ = 0;
64  Mass = CoulombBarrier = MinKinEnergy = MaxKinEnergy = EmissionProbability = 0.0;
65  EvapMass = G4NucleiProperties::GetNuclearMass(theA, theZ);
66  pairingCorrection = G4PairingCorrection::GetInstance();
67 }
68 
70 {}
71 
73 {
74  theProbability->Initialise();
76 }
77 
79 {
80  G4int FragA = fragment->GetA_asInt();
81  G4int FragZ = fragment->GetZ_asInt();
82  ResA = FragA - theA;
83  ResZ = FragZ - theZ;
84 
85  G4double FragmentMass = fragment->GetGroundStateMass();
86  G4double ExEnergy = fragment->GetExcitationEnergy();
87  Mass = FragmentMass + ExEnergy;
88  //G4cout << "G4EvaporationChannel::Initialize Z= " << theZ << " A= " << theA
89  // << " FragZ= " << FragZ << " FragA= " << FragA << G4endl;
90  EmissionProbability = 0.0;
91 
92  // Only channels which are physically allowed are taken into account
93  if (ResA >= ResZ && ResZ > 0 && ResA >= theA) {
94 
95  //Effective excitation energy
96  G4double ResMass = G4NucleiProperties::GetNuclearMass(ResA, ResZ);
97 
98  CoulombBarrier = (0 == theZ) ? 0.0 :
99  theCoulombBarrier->GetCoulombBarrier(ResA,ResZ,ExEnergy);
100 
101  G4double delta0 =
102  std::max(0.0,pairingCorrection->GetPairingCorrection(FragA,FragZ));
103  G4double delta1 =
104  std::max(0.0,pairingCorrection->GetPairingCorrection(ResA,ResZ));
105  ResMass += delta1;
106  /*
107  G4cout << "ExEnergy= " << ExEnergy << " Ec= " << CoulombBarrier
108  << " delta0= " << delta0 << " delta1= " << delta1
109  << " Free= " << Mass - ResMass - EvapMass
110  << G4endl;
111  */
112  // for OPTxs >0 penetration under the barrier is taken into account
113  G4double elim = (0 == OPTxs) ? CoulombBarrier : CoulombBarrier*0.7;
114  if(ExEnergy >= delta0 && Mass >= ResMass + EvapMass + elim) {
115  G4double xm2 = (Mass - EvapMass)*(Mass - EvapMass);
116  G4double xm = Mass - EvapMass - elim;
117  MinKinEnergy = (0.0 == elim) ? 0.0 : std::max(0.5*(xm2 - xm*xm)/Mass, 0.0);
118  MaxKinEnergy = std::max(0.5*(xm2 - ResMass*ResMass)/Mass, 0.0);
119  //G4cout << "Emin= " << MinKinEnergy << " Emax= " << MaxKinEnergy
120  // << " xm= " << xm << G4endl;
121  EmissionProbability = theProbability->
122  TotalProbability(*fragment, MinKinEnergy, MaxKinEnergy, CoulombBarrier);
123  }
124  }
125  //G4cout << "G4EvaporationChannel:: probability= "
126  // << EmissionProbability << G4endl;
127  return EmissionProbability;
128 }
129 
131 {
132  G4Fragment* evFragment = nullptr;
133  G4double ekin = 0.0;
134  if(ResA <= 4 &&
135  ((ResA == 4 && ResZ == 2) || (ResA == 3 && ResZ == 2) ||
136  (ResA == 3 && ResZ == 1) || (ResA == 2 && ResZ == 1) ||
137  (ResA == 1 && ResZ == 1) || (ResA == 1 && ResZ == 0) )) {
138  G4double mres = G4NucleiProperties::GetNuclearMass(ResA, ResZ);
139  ekin = 0.5*(Mass*Mass - mres*mres + EvapMass*EvapMass)/Mass - EvapMass;
140  } else {
141  ekin = theProbability->SampleKineticEnergy(MinKinEnergy, MaxKinEnergy,
142  CoulombBarrier);
143  }
144  G4LorentzVector lv0 = theNucleus->GetMomentum();
145  G4LorentzVector lv(std::sqrt(ekin*(ekin + 2.0*EvapMass))*G4RandomDirection(),
146  ekin + EvapMass);
147  lv.boost(lv0.boostVector());
148 
149  evFragment = new G4Fragment(theA, theZ, lv);
150  lv0 -= lv;
151  theNucleus->SetZandA_asInt(ResZ, ResA);
152  theNucleus->SetMomentum(lv0);
153 
154  return evFragment;
155 }
Hep3Vector boostVector() const
static G4double GetNuclearMass(const G4double A, const G4double Z)
virtual G4Fragment * EmittedFragment(G4Fragment *theNucleus)
G4ThreeVector G4RandomDirection()
virtual G4double GetEmissionProbability(G4Fragment *fragment)
G4EvaporationChannel(G4int A, G4int Z, const G4String &aName, G4EvaporationProbability *, G4VCoulombBarrier *)
int G4int
Definition: G4Types.hh:78
G4double SampleKineticEnergy(G4double minKineticEnergy, G4double maxKineticEnergy, G4double CoulombBarrier=0.0)
G4int GetA_asInt() const
Definition: G4Fragment.hh:266
const G4LorentzVector & GetMomentum() const
Definition: G4Fragment.hh:307
HepLorentzVector & boost(double, double, double)
void SetMomentum(const G4LorentzVector &value)
Definition: G4Fragment.hh:312
G4double GetPairingCorrection(G4int A, G4int Z) const
G4double GetGroundStateMass() const
Definition: G4Fragment.hh:288
static G4PairingCorrection * GetInstance()
T max(const T t1, const T t2)
brief Return the largest of the two arguments
void SetZandA_asInt(G4int Znew, G4int Anew)
Definition: G4Fragment.hh:276
G4int GetZ_asInt() const
Definition: G4Fragment.hh:271
virtual G4double GetCoulombBarrier(G4int ARes, G4int ZRes, G4double U) const =0
double G4double
Definition: G4Types.hh:76
G4double GetExcitationEnergy() const
Definition: G4Fragment.hh:283