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25 //
26 ////////////////////////////////////////////////////////////////////////////////
27 // //
28 // File: G4BetaMinusDecay.cc //
29 // Author: D.H. Wright (SLAC) //
30 // Date: 25 October 2014 //
31 // Modifications: //
32 // 23.08.2023 V.Ivanchenko make it thread safe using static utility //
33 // //
34 ////////////////////////////////////////////////////////////////////////////////
35
36 #include "G4BetaMinusDecay.hh"
37 #include "G4BetaDecayCorrections.hh"
38 #include "G4ThreeVector.hh"
39 #include "G4LorentzVector.hh"
40 #include "G4DynamicParticle.hh"
41 #include "G4DecayProducts.hh"
42 #include "G4PhysicalConstants.hh"
43 #include "G4SystemOfUnits.hh"
44 #include "G4Electron.hh"
45 #include "G4AntiNeutrinoE.hh"
46 #include "G4RandomDirection.hh"
47 #include "G4BetaSpectrumSampler.hh"
48 #include <iostream>
49 #include <iomanip>
50
51 namespace {
52 const G4double eMass = CLHEP::electron_mass_c2;
53 }
54
55 G4BetaMinusDecay::G4BetaMinusDecay(const G4ParticleDefinition* theParentNucleus,
56 const G4double& branch, const G4double& e0,
57 const G4double& excitationE,
58 const G4Ions::G4FloatLevelBase& flb,
59 const G4BetaDecayType& betaType)
60 : G4NuclearDecay("beta- decay", BetaMinus, excitationE, flb),
61 maxEnergy(e0/eMass),
62 estep(maxEnergy/(G4double)(npti - 1))
63 {
64 SetParent(theParentNucleus); // Store name of parent nucleus, delete G4MT_parent
65 SetBR(branch);
66 SetNumberOfDaughters(3);
67
68 fPrimaryIon = theParentNucleus;
69 fLepton = G4Electron::Electron();
70 fNeutrino = G4AntiNeutrinoE::AntiNeutrinoE();
71
72 G4IonTable* theIonTable = G4ParticleTable::GetParticleTable()->GetIonTable();
73 G4int daughterZ = theParentNucleus->GetAtomicNumber() + 1;
74 G4int daughterA = theParentNucleus->GetAtomicMass();
75 fResIon = const_cast<const G4ParticleDefinition*>(theIonTable->GetIon(daughterZ, daughterA,
76 excitationE, flb));
77 parentMass = theParentNucleus->GetPDGMass();
78 resMass = fResIon->GetPDGMass();
79
80 SetUpBetaSpectrumSampler(daughterZ, daughterA, betaType);
81
82 SetDaughter(0, fResIon);
83 SetDaughter(1, fLepton);
84 SetDaughter(2, fNeutrino);
85
86 // Fill G4MT_parent with theParentNucleus (stored by SetParent in ctor)
87 CheckAndFillParent();
88
89 // Fill G4MT_daughters with e-, nu and residual nucleus (stored by SetDaughter)
90 CheckAndFillDaughters();
91 }
92
93 G4DecayProducts* G4BetaMinusDecay::DecayIt(G4double)
94 {
95 // Set up final state
96 // parentParticle is set at rest here because boost with correct momentum
97 // is done later
98 G4DynamicParticle prim(fPrimaryIon, G4ThreeVector(0,0,1), 0.0);
99 G4DecayProducts* products = new G4DecayProducts(prim);
100
101 // Generate electron isotropic in angle, with energy from stored spectrum
102 const G4double eKE = eMass*G4BetaSpectrumSampler::shoot(npti, cdf, estep);
103
104 G4double eMomentum = std::sqrt(eKE*(eKE + 2.*eMass));
105 G4ThreeVector dir = G4RandomDirection();
106 G4DynamicParticle* dp = new G4DynamicParticle(fLepton, dir, eKE);
107 products->PushProducts(dp);
108 /*
109 G4cout << "G4BetaPlusDecay::DecayIt: " << fPrimaryIon->GetParticleName()
110 << " -> " << fResIon->GetParticleName() << " + " << fLepton->GetParticleName()
111 << " + " << fNeutrino->GetParticleName() << " Ee(MeV)=" << eKE
112 << G4endl;
113 */
114
115 // 4-momentum of residual ion and neutrino
116 G4LorentzVector lv(-eMomentum*dir.x(), -eMomentum*dir.y(), -eMomentum*dir.z(),
117 parentMass - eKE - eMass);
118
119 // centrum of mass system
120 G4double M = lv.mag();
121 const G4double elim = CLHEP::eV;
122 G4double edel = M - resMass;
123 // Free energy should be above limit
124 if (edel >= elim) {
125 // neutrino
126 G4double eNu = 0.5*(M - resMass*resMass/M);
127 G4LorentzVector lvnu(eNu*G4RandomDirection(), eNu);
128 lvnu.boost(lv.boostVector());
129 dir = lvnu.vect().unit();
130 dp = new G4DynamicParticle(fNeutrino, dir, lvnu.e());
131 products->PushProducts(dp);
132
133 // residual
134 lv -= lvnu;
135 dir = lv.vect().unit();
136 G4double ekin = std::max(lv.e() - resMass, 0.0);
137 dp = new G4DynamicParticle(fResIon, dir, ekin);
138 products->PushProducts(dp);
139
140 } else {
141 // neglecting relativistic kinematic and giving some energy to neutrino
142 dp = new G4DynamicParticle(fNeutrino, G4RandomDirection(), elim);
143 products->PushProducts(dp);
144 dp = new G4DynamicParticle(fResIon, G4ThreeVector(0.0,0.0,1.0), 0.0);
145 products->PushProducts(dp);
146 }
147
148 return products;
149 }
150
151
152 void
153 G4BetaMinusDecay::SetUpBetaSpectrumSampler(const G4int& daughterZ,
154 const G4int& daughterA,
155 const G4BetaDecayType& betaType)
156 {
157 cdf[0] = 0.0;
158
159 // Check for cases in which Q < 0
160 if (maxEnergy > 0.) {
161 G4BetaDecayCorrections corrections(daughterZ, daughterA);
162
163 // Fill array to store cumulative spectrum
164 G4double ex; // Kinetic energy normalized on electron mass
165 G4double p; // Momentum in units of electron mass
166 G4double f; // Spectral shape function
167 G4double f0 = 0.0;
168 G4double sum = 0.0;
169 for (G4int i = 1; i < npti-1; ++i) {
170 ex = estep*i;
171 p = std::sqrt(ex*(ex + 2.));
172 f = p*(1. + ex)*(maxEnergy - ex)*(maxEnergy - ex);
173
174 // Apply Fermi factor to get allowed shape
175 f *= corrections.FermiFunction(1. + ex);
176
177 // Apply shape factor for forbidden transitions
178 f *= corrections.ShapeFactor(betaType, p, maxEnergy - ex);
179 sum += f + f0;
180 cdf[i] = sum;
181 f0 = f;
182 }
183 cdf[npti-1] = sum + f0;
184 } else {
185 for (G4int i = 1; i < npti; ++i) { cdf[i] = 0.0; }
186 }
187 }
188
189
190 void G4BetaMinusDecay::DumpNuclearInfo()
191 {
192 G4cout << " G4BetaMinusDecay " << fPrimaryIon->GetParticleName()
193 << " -> " << fResIon->GetParticleName() << " + " << fLepton->GetParticleName()
194 << " + " << fNeutrino->GetParticleName() << " Eemax(MeV)="
195 << maxEnergy*eMass << " BR=" << GetBR() << "%" << G4endl;
196 }
197
198