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Wright (SLAC) 29 // Author: D.H. Wright (SLAC) // 30 // Date: 14 November 2014 30 // Date: 14 November 2014 // 31 // Modifications: << 32 // 23.08.2023 V.Ivanchenko << 33 // 31 // // 34 ////////////////////////////////////////////// 32 //////////////////////////////////////////////////////////////////////////////// 35 33 36 #include "G4BetaPlusDecay.hh" 34 #include "G4BetaPlusDecay.hh" 37 #include "G4BetaDecayCorrections.hh" 35 #include "G4BetaDecayCorrections.hh" 38 #include "G4IonTable.hh" 36 #include "G4IonTable.hh" 39 #include "G4ThreeVector.hh" 37 #include "G4ThreeVector.hh" 40 #include "G4LorentzVector.hh" << 41 #include "G4DynamicParticle.hh" 38 #include "G4DynamicParticle.hh" 42 #include "G4DecayProducts.hh" 39 #include "G4DecayProducts.hh" 43 #include "G4PhysicalConstants.hh" 40 #include "G4PhysicalConstants.hh" 44 #include "G4SystemOfUnits.hh" 41 #include "G4SystemOfUnits.hh" 45 #include "G4Positron.hh" << 46 #include "G4NeutrinoE.hh" << 47 #include "G4RandomDirection.hh" << 48 #include "G4BetaSpectrumSampler.hh" << 49 #include <iostream> 42 #include <iostream> 50 #include <iomanip> 43 #include <iomanip> 51 44 52 namespace { << 53 const G4double eMass = CLHEP::electron_mass_ << 54 } << 55 << 56 G4BetaPlusDecay::G4BetaPlusDecay(const G4Parti 45 G4BetaPlusDecay::G4BetaPlusDecay(const G4ParticleDefinition* theParentNucleus, 57 const G4doubl 46 const G4double& branch, const G4double& e0, 58 const G4doubl 47 const G4double& excitationE, 59 const G4Ions: 48 const G4Ions::G4FloatLevelBase& flb, 60 const G4BetaD 49 const G4BetaDecayType& betaType) 61 : G4NuclearDecay("beta+ decay", BetaPlus, exc 50 : G4NuclearDecay("beta+ decay", BetaPlus, excitationE, flb), 62 maxEnergy(e0/eMass - 2.0), << 51 endpointEnergy(e0 - 2.*CLHEP::electron_mass_c2) 63 estep(maxEnergy/(G4double)(npti - 1)) << 64 { 52 { 65 SetParent(theParentNucleus); // Store name 53 SetParent(theParentNucleus); // Store name of parent nucleus, delete G4MT_parent 66 SetBR(branch); 54 SetBR(branch); 67 SetNumberOfDaughters(3); << 68 << 69 fPrimaryIon = theParentNucleus; << 70 fLepton = G4Positron::Positron(); << 71 fNeutrino = G4NeutrinoE::NeutrinoE(); << 72 55 73 G4IonTable* theIonTable = G4ParticleTable::G << 56 SetNumberOfDaughters(3); >> 57 G4IonTable* theIonTable = >> 58 (G4IonTable*)(G4ParticleTable::GetParticleTable()->GetIonTable()); 74 G4int daughterZ = theParentNucleus->GetAtomi 59 G4int daughterZ = theParentNucleus->GetAtomicNumber() - 1; 75 G4int daughterA = theParentNucleus->GetAtomi << 60 G4int daughterA = theParentNucleus->GetAtomicMass(); 76 fResIon = const_cast<const G4ParticleDefinit << 61 SetDaughter(0, theIonTable->GetIon(daughterZ, daughterA, excitationE, flb) ); 77 << 62 SetUpBetaSpectrumSampler(daughterZ, daughterA, betaType); >> 63 SetDaughter(1, "e+"); >> 64 SetDaughter(2, "nu_e"); >> 65 } 78 66 79 parentMass = theParentNucleus->GetPDGMass(); << 80 resMass = fResIon->GetPDGMass(); << 81 67 82 SetUpBetaSpectrumSampler(daughterZ, daughter << 68 G4BetaPlusDecay::~G4BetaPlusDecay() >> 69 { >> 70 delete spectrumSampler; >> 71 } 83 72 84 SetDaughter(0, fResIon); << 85 SetDaughter(1, fLepton); << 86 SetDaughter(2, fNeutrino); << 87 73 >> 74 G4DecayProducts* G4BetaPlusDecay::DecayIt(G4double) >> 75 { 88 // Fill G4MT_parent with theParentNucleus (s 76 // Fill G4MT_parent with theParentNucleus (stored by SetParent in ctor) 89 CheckAndFillParent(); 77 CheckAndFillParent(); 90 78 91 // Fill G4MT_daughters with e+, nu and resid << 79 // Fill G4MT_daughters with e-, nu and residual nucleus (stored by SetDaughter) 92 CheckAndFillDaughters(); 80 CheckAndFillDaughters(); 93 } << 94 81 95 G4DecayProducts* G4BetaPlusDecay::DecayIt(G4do << 82 G4double parentMass = G4MT_parent->GetPDGMass(); 96 { << 83 G4double eMass = G4MT_daughters[1]->GetPDGMass(); >> 84 G4double nucleusMass = G4MT_daughters[0]->GetPDGMass(); 97 // Set up final state 85 // Set up final state 98 // parentParticle is set at rest here becaus 86 // parentParticle is set at rest here because boost with correct momentum 99 // is done later 87 // is done later 100 G4DynamicParticle prim(fPrimaryIon, G4ThreeV << 88 G4DynamicParticle parentParticle(G4MT_parent, G4ThreeVector(0,0,0), 0.0); 101 G4DecayProducts* products = new G4DecayProdu << 89 G4DecayProducts* products = new G4DecayProducts(parentParticle); 102 << 103 // Generate positron isotropic in angle, wit << 104 const G4double eKE = eMass*G4BetaSpectrumSam << 105 90 106 G4double eMomentum = std::sqrt(eKE*(eKE + 2. << 91 if (spectrumSampler) { 107 G4ThreeVector dir = G4RandomDirection(); << 92 // Generate positron isotropic in angle, with energy from stored spectrum 108 G4DynamicParticle* dp = new G4DynamicParticl << 93 G4double eKE = endpointEnergy*spectrumSampler->shoot(G4Random::getTheEngine() ); 109 products->PushProducts(dp); << 94 G4double eMomentum = std::sqrt(eKE*(eKE + 2.*eMass) ); 110 /* << 95 111 G4cout << "G4BetaPlusDecay::DecayIt: " << fP << 96 G4double cosTheta = 2.*G4UniformRand() - 1.0; 112 << " -> " << fResIon->GetParticleName() << << 97 G4double sinTheta = std::sqrt(1.0 - cosTheta*cosTheta); 113 << " + " << fNeutrino->GetParticleName() << << 98 G4double phi = twopi*G4UniformRand()*rad; 114 << G4endl; << 99 G4double sinPhi = std::sin(phi); 115 */ << 100 G4double cosPhi = std::cos(phi); 116 // 4-momentum of residual ion and neutrino << 101 117 G4LorentzVector lv(-eMomentum*dir.x(), -eMom << 102 G4ParticleMomentum eDirection(sinTheta*cosPhi, sinTheta*sinPhi, cosTheta); 118 parentMass - eKE - eMass) << 103 G4DynamicParticle* dynamicPositron 119 << 104 = new G4DynamicParticle(G4MT_daughters[1], eDirection*eMomentum); 120 const G4double elim = CLHEP::eV; << 105 products->PushProducts(dynamicPositron); 121 // centrum of mass system << 106 122 G4double M = lv.mag(); << 107 // Generate neutrino with angle relative to positron, and energy from 123 G4double edel = M - resMass; << 108 // energy-momentum conservation using endpoint energy of reaction 124 // Free energy should be above limit << 109 G4double cosThetaENu = 2.*G4UniformRand() - 1.; 125 if (edel >= elim) { << 110 G4double eTE = eMass + eKE; 126 // neutrino << 111 G4double nuEnergy = ((endpointEnergy - eKE)*(parentMass + nucleusMass - eTE) 127 G4double eNu = 0.5*(M - resMass*resMass/M) << 112 - eMomentum*eMomentum)/(parentMass - eTE + eMomentum*cosThetaENu)/2.; 128 G4LorentzVector lvnu(eNu*G4RandomDirection << 113 129 lvnu.boost(lv.boostVector()); << 114 G4double sinThetaENu = std::sqrt(1.0 - cosThetaENu*cosThetaENu); 130 dir = lvnu.vect().unit(); << 115 phi = twopi*G4UniformRand()*rad; 131 dp = new G4DynamicParticle(fNeutrino, dir, << 116 G4double sinPhiNu = std::sin(phi); 132 products->PushProducts(dp); << 117 G4double cosPhiNu = std::cos(phi); 133 << 118 134 // residual << 119 G4ParticleMomentum nuDirection; 135 lv -= lvnu; << 120 nuDirection.setX(sinThetaENu*cosPhiNu*cosTheta*cosPhi - 136 dir = lv.vect().unit(); << 121 sinThetaENu*sinPhiNu*sinPhi + cosThetaENu*sinTheta*cosPhi); 137 G4double ekin = std::max(lv.e() - resMass, << 122 nuDirection.setY(sinThetaENu*cosPhiNu*cosTheta*sinPhi + 138 dp = new G4DynamicParticle(fResIon, dir, e << 123 sinThetaENu*sinPhiNu*cosPhi + cosThetaENu*sinTheta*sinPhi); 139 products->PushProducts(dp); << 124 nuDirection.setZ(-sinThetaENu*cosPhiNu*sinTheta + cosThetaENu*cosTheta); >> 125 >> 126 G4DynamicParticle* dynamicNeutrino >> 127 = new G4DynamicParticle(G4MT_daughters[2], nuDirection*nuEnergy); >> 128 products->PushProducts(dynamicNeutrino); >> 129 >> 130 // Generate daughter nucleus from sum of positron and neutrino 4-vectors: >> 131 // p_D = - p_e - p_nu >> 132 G4DynamicParticle* dynamicDaughter = >> 133 new G4DynamicParticle(G4MT_daughters[0], >> 134 -eDirection*eMomentum - nuDirection*nuEnergy); >> 135 products->PushProducts(dynamicDaughter); 140 136 141 } else { 137 } else { 142 // neglecting relativistic kinematic and g << 138 // positron energy below threshold -> no decay 143 dp = new G4DynamicParticle(fNeutrino, G4Ra << 139 G4DynamicParticle* noDecay = 144 products->PushProducts(dp); << 140 new G4DynamicParticle(G4MT_parent, G4ThreeVector(0,0,0), 0.0); 145 dp = new G4DynamicParticle(fResIon, G4Thre << 141 products->PushProducts(noDecay); 146 products->PushProducts(dp); << 147 } 142 } 148 143 >> 144 // Check energy conservation against endpoint value, not nuclear masses >> 145 /* >> 146 G4int nProd = products->entries(); >> 147 G4DynamicParticle* temp = 0; >> 148 G4double Esum = 0.0; >> 149 for (G4int i = 0; i < nProd; i++) { >> 150 temp = products->operator[](i); >> 151 Esum += temp->GetKineticEnergy(); >> 152 } >> 153 G4double eCons = (endpointEnergy - Esum)/keV; >> 154 if (eCons > 0.001) G4cout << " Beta+ check: eCons (keV) = " << eCons << G4endl; >> 155 */ 149 return products; 156 return products; 150 } 157 } 151 158 152 159 153 void 160 void 154 G4BetaPlusDecay::SetUpBetaSpectrumSampler(cons 161 G4BetaPlusDecay::SetUpBetaSpectrumSampler(const G4int& daughterZ, 155 cons 162 const G4int& daughterA, 156 cons 163 const G4BetaDecayType& betaType) 157 { 164 { 158 cdf[0] = 0.0; << 165 G4double e0 = endpointEnergy/CLHEP::electron_mass_c2; >> 166 G4BetaDecayCorrections corrections(-daughterZ, daughterA); >> 167 spectrumSampler = 0; 159 168 160 // Check for cases in which Q < 2Me (e.g. z6 169 // Check for cases in which Q < 2Me (e.g. z67.a162) 161 if (maxEnergy > 0.) { << 170 if (e0 > 0.) { 162 G4BetaDecayCorrections corrections(-daught << 171 // Array to store spectrum pdf 163 << 172 G4int npti = 100; 164 // Fill array to store cumulative spectrum << 173 G4double* pdf = new G4double[npti]; 165 G4double ex; // Positron kinetic energy << 174 166 G4double p; // Positron momentum in unit << 175 G4double e; // Total positron energy in units of electron mass 167 G4double f; // Spectral shape function << 176 G4double p; // Positron momentum in units of electron mass 168 G4double f0 = 0.0; << 177 G4double f; // Spectral shap function 169 G4double sum = 0.0; << 178 for (G4int ptn = 0; ptn < npti; ptn++) { 170 for (G4int i = 1; i < npti-1; ++i) { << 179 // Calculate simple phase space 171 ex = estep*i; << 180 e = 1. + e0*(ptn + 0.5)/G4double(npti); 172 p = std::sqrt(ex*(ex + 2.)); << 181 p = std::sqrt(e*e - 1.); 173 f = p*(1. + ex)*(maxEnergy - ex)*(maxEne << 182 f = p*e*(e0 - e + 1.)*(e0 - e + 1.); 174 183 175 // Apply Fermi factor to get allowed sha 184 // Apply Fermi factor to get allowed shape 176 f *= corrections.FermiFunction(1. + ex); << 185 f *= corrections.FermiFunction(e); 177 186 178 // Apply shape factor for forbidden tran 187 // Apply shape factor for forbidden transitions 179 f *= corrections.ShapeFactor(betaType, p << 188 f *= corrections.ShapeFactor(betaType, p, e0-e+1.); 180 sum += f + f0; << 189 pdf[ptn] = f; 181 cdf[i] = sum; << 182 f0 = f; << 183 } 190 } 184 cdf[npti-1] = sum + f0; << 191 spectrumSampler = new G4RandGeneral(pdf, npti); 185 } else { << 192 delete[] pdf; 186 for (G4int i = 0; i < npti; ++i) { cdf[i] << 187 } 193 } 188 } 194 } 189 195 >> 196 190 void G4BetaPlusDecay::DumpNuclearInfo() 197 void G4BetaPlusDecay::DumpNuclearInfo() 191 { 198 { 192 G4cout << " G4BetaPlusDecay " << fPrimaryIo << 199 G4cout << " G4BetaPlusDecay for parent nucleus " << GetParentName() << G4endl; 193 << " -> " << fResIon->GetParticleName() << << 200 G4cout << " decays to " << GetDaughterName(0) << " , " << GetDaughterName(1) 194 << " + " << fNeutrino->GetParticleName() << << 201 << " and " << GetDaughterName(2) << " with branching ratio " << GetBR() 195 << maxEnergy*eMass << " BR=" << GetBR() << << 202 << "% and endpoint energy " << endpointEnergy/keV << " keV " << G4endl; 196 } 203 } >> 204 197 205