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27 //
28 // File: G4BetaPlusDecay.cc
29 // Author: D.H. Wright (SLAC)
30 // Date: 14 November 2014
31 // Modifications:
32 // 23.08.2023 V.Ivanchenko
33 //
34 //////////////////////////////////////////////
35
36 #include "G4BetaPlusDecay.hh"
37 #include "G4BetaDecayCorrections.hh"
38 #include "G4IonTable.hh"
39 #include "G4ThreeVector.hh"
40 #include "G4LorentzVector.hh"
41 #include "G4DynamicParticle.hh"
42 #include "G4DecayProducts.hh"
43 #include "G4PhysicalConstants.hh"
44 #include "G4SystemOfUnits.hh"
45 #include "G4Positron.hh"
46 #include "G4NeutrinoE.hh"
47 #include "G4RandomDirection.hh"
48 #include "G4BetaSpectrumSampler.hh"
49 #include <iostream>
50 #include <iomanip>
51
52 namespace {
53 const G4double eMass = CLHEP::electron_mass_
54 }
55
56 G4BetaPlusDecay::G4BetaPlusDecay(const G4Parti
57 const G4doubl
58 const G4doubl
59 const G4Ions:
60 const G4BetaD
61 : G4NuclearDecay("beta+ decay", BetaPlus, exc
62 maxEnergy(e0/eMass - 2.0),
63 estep(maxEnergy/(G4double)(npti - 1))
64 {
65 SetParent(theParentNucleus); // Store name
66 SetBR(branch);
67 SetNumberOfDaughters(3);
68
69 fPrimaryIon = theParentNucleus;
70 fLepton = G4Positron::Positron();
71 fNeutrino = G4NeutrinoE::NeutrinoE();
72
73 G4IonTable* theIonTable = G4ParticleTable::G
74 G4int daughterZ = theParentNucleus->GetAtomi
75 G4int daughterA = theParentNucleus->GetAtomi
76 fResIon = const_cast<const G4ParticleDefinit
77
78
79 parentMass = theParentNucleus->GetPDGMass();
80 resMass = fResIon->GetPDGMass();
81
82 SetUpBetaSpectrumSampler(daughterZ, daughter
83
84 SetDaughter(0, fResIon);
85 SetDaughter(1, fLepton);
86 SetDaughter(2, fNeutrino);
87
88 // Fill G4MT_parent with theParentNucleus (s
89 CheckAndFillParent();
90
91 // Fill G4MT_daughters with e+, nu and resid
92 CheckAndFillDaughters();
93 }
94
95 G4DecayProducts* G4BetaPlusDecay::DecayIt(G4do
96 {
97 // Set up final state
98 // parentParticle is set at rest here becaus
99 // is done later
100 G4DynamicParticle prim(fPrimaryIon, G4ThreeV
101 G4DecayProducts* products = new G4DecayProdu
102
103 // Generate positron isotropic in angle, wit
104 const G4double eKE = eMass*G4BetaSpectrumSam
105
106 G4double eMomentum = std::sqrt(eKE*(eKE + 2.
107 G4ThreeVector dir = G4RandomDirection();
108 G4DynamicParticle* dp = new G4DynamicParticl
109 products->PushProducts(dp);
110 /*
111 G4cout << "G4BetaPlusDecay::DecayIt: " << fP
112 << " -> " << fResIon->GetParticleName() <<
113 << " + " << fNeutrino->GetParticleName() <<
114 << G4endl;
115 */
116 // 4-momentum of residual ion and neutrino
117 G4LorentzVector lv(-eMomentum*dir.x(), -eMom
118 parentMass - eKE - eMass)
119
120 const G4double elim = CLHEP::eV;
121 // centrum of mass system
122 G4double M = lv.mag();
123 G4double edel = M - resMass;
124 // Free energy should be above limit
125 if (edel >= elim) {
126 // neutrino
127 G4double eNu = 0.5*(M - resMass*resMass/M)
128 G4LorentzVector lvnu(eNu*G4RandomDirection
129 lvnu.boost(lv.boostVector());
130 dir = lvnu.vect().unit();
131 dp = new G4DynamicParticle(fNeutrino, dir,
132 products->PushProducts(dp);
133
134 // residual
135 lv -= lvnu;
136 dir = lv.vect().unit();
137 G4double ekin = std::max(lv.e() - resMass,
138 dp = new G4DynamicParticle(fResIon, dir, e
139 products->PushProducts(dp);
140
141 } else {
142 // neglecting relativistic kinematic and g
143 dp = new G4DynamicParticle(fNeutrino, G4Ra
144 products->PushProducts(dp);
145 dp = new G4DynamicParticle(fResIon, G4Thre
146 products->PushProducts(dp);
147 }
148
149 return products;
150 }
151
152
153 void
154 G4BetaPlusDecay::SetUpBetaSpectrumSampler(cons
155 cons
156 cons
157 {
158 cdf[0] = 0.0;
159
160 // Check for cases in which Q < 2Me (e.g. z6
161 if (maxEnergy > 0.) {
162 G4BetaDecayCorrections corrections(-daught
163
164 // Fill array to store cumulative spectrum
165 G4double ex; // Positron kinetic energy
166 G4double p; // Positron momentum in unit
167 G4double f; // Spectral shape function
168 G4double f0 = 0.0;
169 G4double sum = 0.0;
170 for (G4int i = 1; i < npti-1; ++i) {
171 ex = estep*i;
172 p = std::sqrt(ex*(ex + 2.));
173 f = p*(1. + ex)*(maxEnergy - ex)*(maxEne
174
175 // Apply Fermi factor to get allowed sha
176 f *= corrections.FermiFunction(1. + ex);
177
178 // Apply shape factor for forbidden tran
179 f *= corrections.ShapeFactor(betaType, p
180 sum += f + f0;
181 cdf[i] = sum;
182 f0 = f;
183 }
184 cdf[npti-1] = sum + f0;
185 } else {
186 for (G4int i = 0; i < npti; ++i) { cdf[i]
187 }
188 }
189
190 void G4BetaPlusDecay::DumpNuclearInfo()
191 {
192 G4cout << " G4BetaPlusDecay " << fPrimaryIo
193 << " -> " << fResIon->GetParticleName() <<
194 << " + " << fNeutrino->GetParticleName() <<
195 << maxEnergy*eMass << " BR=" << GetBR() <<
196 }
197