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G4UnstableFragmentBreakUp.cc
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26 // $Id$
27 //
28 // -------------------------------------------------------------------
29 // GEANT 4 class file
30 //
31 // CERN, Geneva, Switzerland
32 //
33 // File name: G4UnstableFragmentBreakUp
34 //
35 // Author: V.Ivanchenko
36 //
37 // Creation date: 11 May 2010
38 //
39 //Modifications:
40 //
41 // -------------------------------------------------------------------
42 //
43 
45 #include "Randomize.hh"
46 #include "G4PhysicalConstants.hh"
47 #include "G4LorentzVector.hh"
48 #include "G4Fragment.hh"
49 #include "G4FragmentVector.hh"
50 #include "G4NucleiProperties.hh"
51 #include "G4NistManager.hh"
52 
53 G4int G4UnstableFragmentBreakUp::Zfr[6] = {0};
54 G4int G4UnstableFragmentBreakUp::Afr[6] = {0};
55 G4double G4UnstableFragmentBreakUp::masses[6] = {0.0};
56 
58  :verbose(0)
59 {
60  fNistManager = G4NistManager::Instance();
61  if(0 == Afr[0]) {
62  G4int z[6] = {0, 1, 1, 1, 2, 2};
63  G4int a[6] = {1, 1, 2, 3, 3, 4};
64  for(G4int i=0; i<6; ++i) {
65  Zfr[i] = z[i];
66  Afr[i] = a[i];
67  masses[i] = G4NucleiProperties::GetNuclearMass(a[i], z[i]);
68  }
69  }
70 }
71 
73 {}
74 
76 {
77  return 0;
78 }
79 
81 {
82  //G4cout << "G4UnstableFragmentBreakUp::BreakUpFragment" << G4endl;
83  G4FragmentVector * theResult = new G4FragmentVector();
84 
85  G4int Z = nucleus->GetZ_asInt();
86  G4int A = nucleus->GetA_asInt();
87  G4int Amax = A;
88  G4LorentzVector lv = nucleus->GetMomentum();
89  G4double time = nucleus->GetCreationTime();
90 
91  G4double deltaE, mass, mass1(0.0), mass2(0.0);
92  G4int i, index;
93 
94  // Starts loop over evaporated particles, loop is limited by number
95  // of nucleons
96  for(G4int ia=0; ia<Amax; ++ia) {
97 
98  mass = lv.mag();
99  deltaE = 0.0;
100  index = -1;
101  for(i=0; i<6; ++i) {
102  G4int Zres = Z - Zfr[i];
103  G4int Ares = A - Afr[i];
104  if(Zres >= 0 && Ares >= Zres && Ares > 0) {
106  G4double de = mass - m1 - masses[i];
107  if(de > deltaE) {
108  mass1 = m1;
109  mass2 = masses[i];
110  deltaE= de;
111  index = i;
112  }
113  }
114  }
115 
116  // no decay channels
117  if(index < 0) { break; }
118 
119  // compute energy of light fragment
120  G4double e2 = 0.5*((mass - mass1)*(mass + mass1) + mass2*mass2)/mass;
121  if(e2 < mass2) { break; }
122 
123  // sample decay
124  G4ThreeVector bst = lv.boostVector();
125 
126  G4double cosTheta = 1. - 2. * G4UniformRand();
127  G4double sinTheta = std::sqrt(1. - cosTheta * cosTheta);
128  G4double phi = twopi * G4UniformRand();
129  G4double mom = std::sqrt((e2 - mass2)*(e2 + mass2));
130  G4LorentzVector mom2(mom * sinTheta * std::cos(phi),
131  mom * sinTheta * std::sin(phi),
132  mom * cosTheta,
133  e2);
134  mom2.boost(bst);
135  G4Fragment* fr = new G4Fragment(Afr[index], Zfr[index], mom2);
136  fr->SetCreationTime(time);
137  theResult->push_back(fr);
138 
139  // residual
140  lv -= mom2;
141  Z -= Zfr[index];
142  A -= Afr[index];
143  }
144 
145  // updated fragment
146  if( theResult->size() > 0) {
147  nucleus->SetZandA_asInt(Z, A);
148  nucleus->SetMomentum(lv);
149  }
150 
151  return theResult;
152 }
153 
155 {
156  return 0;
157 }
158 
160 {
161  return 0.0;
162 }