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26 ////////////////////////////////////////////// 26 ////////////////////////////////////////////////////////////////////////////////
27 // 27 // //
28 // File: G4NeutronDecay.cc 28 // File: G4NeutronDecay.cc //
29 // Author: L.G. Sarmiento (Lund) 29 // Author: L.G. Sarmiento (Lund) //
30 // Date: 10 October 2015 30 // Date: 10 October 2015 //
31 // 31 // //
32 ////////////////////////////////////////////// 32 ////////////////////////////////////////////////////////////////////////////////
33 33
34 #include "G4NeutronDecay.hh" 34 #include "G4NeutronDecay.hh"
35 #include "G4IonTable.hh" 35 #include "G4IonTable.hh"
36 #include "Randomize.hh" 36 #include "Randomize.hh"
37 #include "G4ThreeVector.hh" 37 #include "G4ThreeVector.hh"
38 #include "G4DynamicParticle.hh" 38 #include "G4DynamicParticle.hh"
39 #include "G4DecayProducts.hh" 39 #include "G4DecayProducts.hh"
40 #include "G4PhysicalConstants.hh" 40 #include "G4PhysicalConstants.hh"
41 #include "G4SystemOfUnits.hh" 41 #include "G4SystemOfUnits.hh"
42 #include <iostream> 42 #include <iostream>
43 #include <iomanip> 43 #include <iomanip>
44 44
45 G4NeutronDecay::G4NeutronDecay(const G4Particl 45 G4NeutronDecay::G4NeutronDecay(const G4ParticleDefinition* theParentNucleus,
46 const G4double& br 46 const G4double& branch, const G4double& Qvalue,
47 const G4double& ex 47 const G4double& excitationE,
48 const G4Ions::G4Fl 48 const G4Ions::G4FloatLevelBase& flb)
49 : G4NuclearDecay("neutron decay", Neutron, ex 49 : G4NuclearDecay("neutron decay", Neutron, excitationE, flb), transitionQ(Qvalue)
50 { 50 {
51 SetParent(theParentNucleus); // Store name 51 SetParent(theParentNucleus); // Store name of parent nucleus, delete G4MT_parent
52 SetBR(branch); 52 SetBR(branch);
53 53
54 SetNumberOfDaughters(2); 54 SetNumberOfDaughters(2);
55 G4IonTable* theIonTable = 55 G4IonTable* theIonTable =
56 (G4IonTable*)(G4ParticleTable::GetParticle 56 (G4IonTable*)(G4ParticleTable::GetParticleTable()->GetIonTable());
57 G4int daughterZ = theParentNucleus->GetAtomi 57 G4int daughterZ = theParentNucleus->GetAtomicNumber();
58 G4int daughterA = theParentNucleus->GetAtomi 58 G4int daughterA = theParentNucleus->GetAtomicMass() - 1;
59 SetDaughter(0, theIonTable->GetIon(daughterZ 59 SetDaughter(0, theIonTable->GetIon(daughterZ, daughterA, excitationE, flb) );
60 SetDaughter(1, "neutron"); 60 SetDaughter(1, "neutron");
61 } 61 }
62 62
63 63
64 G4NeutronDecay::~G4NeutronDecay() 64 G4NeutronDecay::~G4NeutronDecay()
65 {} 65 {}
66 66
67 67
68 G4DecayProducts* G4NeutronDecay::DecayIt(G4dou 68 G4DecayProducts* G4NeutronDecay::DecayIt(G4double)
69 { 69 {
70 // Fill G4MT_parent with theParentNucleus (s 70 // Fill G4MT_parent with theParentNucleus (stored by SetParent in ctor)
71 CheckAndFillParent(); 71 CheckAndFillParent();
72 72
73 // Fill G4MT_daughters with neutron and resi 73 // Fill G4MT_daughters with neutron and residual nucleus (stored by SetDaughter)
74 CheckAndFillDaughters(); 74 CheckAndFillDaughters();
75 75
76 G4double neutronMass = G4MT_daughters[1]->Ge 76 G4double neutronMass = G4MT_daughters[1]->GetPDGMass();
77 // Excitation energy included in PDG mass 77 // Excitation energy included in PDG mass
78 G4double nucleusMass = G4MT_daughters[0]->Ge 78 G4double nucleusMass = G4MT_daughters[0]->GetPDGMass();
79 79
80 // Q value was calculated from atomic masses 80 // Q value was calculated from atomic masses.
81 // Use it to get correct neutron energy. 81 // Use it to get correct neutron energy.
82 G4double cmMomentum = std::sqrt(transitionQ* 82 G4double cmMomentum = std::sqrt(transitionQ*(transitionQ + 2.*neutronMass)*
83 (transitionQ + 83 (transitionQ + 2.*nucleusMass)*
84 (transitionQ + 84 (transitionQ + 2.*neutronMass + 2.*nucleusMass) )/
85 (transitionQ + 85 (transitionQ + neutronMass + nucleusMass)/2.;
86 86
87 // Set up final state 87 // Set up final state
88 // parentParticle is set at rest here becaus 88 // parentParticle is set at rest here because boost with correct momentum
89 // is done later 89 // is done later
90 G4DynamicParticle parentParticle(G4MT_parent 90 G4DynamicParticle parentParticle(G4MT_parent, G4ThreeVector(0,0,0), 0.0);
91 G4DecayProducts* products = new G4DecayProdu 91 G4DecayProducts* products = new G4DecayProducts(parentParticle);
92 92
93 G4double costheta = 2.*G4UniformRand()-1.0; 93 G4double costheta = 2.*G4UniformRand()-1.0;
94 G4double sintheta = std::sqrt(1.0 - costheta 94 G4double sintheta = std::sqrt(1.0 - costheta*costheta);
95 G4double phi = twopi*G4UniformRand()*rad; 95 G4double phi = twopi*G4UniformRand()*rad;
96 G4ThreeVector direction(sintheta*std::cos(ph 96 G4ThreeVector direction(sintheta*std::cos(phi),sintheta*std::sin(phi),
97 costheta); 97 costheta);
98 98
99 G4double KE = std::sqrt(cmMomentum*cmMomentu 99 G4double KE = std::sqrt(cmMomentum*cmMomentum + neutronMass*neutronMass)
100 - neutronMass; 100 - neutronMass;
101 G4DynamicParticle* daughterparticle = 101 G4DynamicParticle* daughterparticle =
102 new G4DynamicParticle(G4MT_daughters[1], d 102 new G4DynamicParticle(G4MT_daughters[1], direction, KE, neutronMass);
103 products->PushProducts(daughterparticle); 103 products->PushProducts(daughterparticle);
104 104
105 KE = std::sqrt(cmMomentum*cmMomentum + nucle 105 KE = std::sqrt(cmMomentum*cmMomentum + nucleusMass*nucleusMass) - nucleusMass;
106 daughterparticle = 106 daughterparticle =
107 new G4DynamicParticle(G4MT_daughters[0], - 107 new G4DynamicParticle(G4MT_daughters[0], -1.0*direction, KE, nucleusMass);
108 products->PushProducts(daughterparticle); 108 products->PushProducts(daughterparticle);
109 109
110 // Energy conservation check 110 // Energy conservation check
111 // For neutron decays, do final energy check 111 // For neutron decays, do final energy check against reaction Q value
112 // which is well-measured using atomic mass 112 // which is well-measured using atomic mass differences. Nuclear masses
113 // should not be used since they are not usu 113 // should not be used since they are not usually directly measured and we
114 // always decay atoms and not fully stripped 114 // always decay atoms and not fully stripped nuclei.
115 /* 115 /*
116 G4int nProd = products->entries(); 116 G4int nProd = products->entries();
117 G4DynamicParticle* temp = 0; 117 G4DynamicParticle* temp = 0;
118 G4double Esum = 0.0; 118 G4double Esum = 0.0;
119 for (G4int i = 0; i < nProd; i++) { 119 for (G4int i = 0; i < nProd; i++) {
120 temp = products->operator[](i); 120 temp = products->operator[](i);
121 Esum += temp->GetKineticEnergy(); 121 Esum += temp->GetKineticEnergy();
122 } 122 }
123 G4double eCons = (transitionQ - Esum)/keV; 123 G4double eCons = (transitionQ - Esum)/keV;
124 if (eCons > 1.e-07) G4cout << " Neutron deca 124 if (eCons > 1.e-07) G4cout << " Neutron decay check: Ediff (keV) = " << eCons << G4endl;
125 */ 125 */
126 return products; 126 return products;
127 } 127 }
128 128
129 129
130 void G4NeutronDecay::DumpNuclearInfo() 130 void G4NeutronDecay::DumpNuclearInfo()
131 { 131 {
132 G4cout << " G4NeutronDecay for parent nucleu 132 G4cout << " G4NeutronDecay for parent nucleus " << GetParentName() << G4endl;
133 G4cout << " decays to " << GetDaughterName(0 133 G4cout << " decays to " << GetDaughterName(0) << " + " << GetDaughterName(1)
134 << " with branching ratio " << GetBR( 134 << " with branching ratio " << GetBR() << "% and Q value "
135 << transitionQ << G4endl; 135 << transitionQ << G4endl;
136 } 136 }
137 137
138 138