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27 // -------------------------------------------------------------------
28 // GEANT 4 class implementation file
29 //
30 // CERN, Geneva, Switzerland
31 //
32 // File name: G4ProtonField.cc
33 //
34 // Author: Alessandro Brunengo (Alessandro.Brunengo@ge.infn.it)
35 //
36 // Creation date: 5 June 2000
37 // -------------------------------------------------------------------
38
39 #include "G4ProtonField.hh"
40 #include "G4PhysicalConstants.hh"
41 #include "G4SystemOfUnits.hh"
42 #include "G4VNuclearDensity.hh"
43 #include "G4FermiMomentum.hh"
44 #include "G4V3DNucleus.hh"
45 #include "G4Pow.hh"
46
47 G4ProtonField::G4ProtonField(G4V3DNucleus * aNucleus) :
48 G4VNuclearField(aNucleus), theDensity(theNucleus->GetNuclearDensity())
49 {
50 theA = theNucleus->GetMassNumber();
51 theZ = theNucleus->GetCharge();
52 theBarrier = GetBarrier();
53 theRadius = 2.*theNucleus->GetOuterRadius();
54 theFermi.Init(theA, theZ);
55 for (G4double aR=0.;aR<theRadius; aR+=0.3*fermi)
56 {
57 G4ThreeVector aPosition(0,0,aR);
58 G4double density = GetDensity(aPosition);
59 G4double fermiMom = GetFermiMomentum(density);
60 theFermiMomBuffer.push_back(fermiMom);
61 }
62 {
63 G4ThreeVector aPosition(0,0,theRadius);
64 G4double density = GetDensity(aPosition);
65 G4double fermiMom = GetFermiMomentum(density);
66 theFermiMomBuffer.push_back(fermiMom);
67 }
68 {
69 G4ThreeVector aPosition(0,0,theRadius+0.001*fermi);
70 theFermiMomBuffer.push_back(0);
71 }
72 {
73 G4ThreeVector aPosition(0,0,1.*m);
74 theFermiMomBuffer.push_back(0);
75 }
76 }
77
78
79 G4ProtonField::~G4ProtonField()
80 { }
81
82 G4double G4ProtonField::GetField(const G4ThreeVector & aPosition)
83 {
84 //G4cout << " Fermi Potential " << (fermiMom*fermiMom)/(2*proton_mass_c2) <<G4endl;
85 G4double x = aPosition.mag();
86 unsigned int index = static_cast<unsigned int>(x/(0.3*fermi));
87 if((index+2) > theFermiMomBuffer.size()) return theFermiMomBuffer.back();
88 G4double y1 = theFermiMomBuffer[index];
89 G4double y2 = theFermiMomBuffer[index+1];
90 G4double x1 = (0.3*fermi)*index;
91 G4double x2 = (0.3*fermi)*(index+1);
92 G4double fermiMom = y1 + (x-x1)*(y2-y1)/(x2-x1);
93 G4double y = -1*(fermiMom*fermiMom)/(2*proton_mass_c2)+theBarrier;
94 // G4cout <<" Protonfield test "<<index<<" "<< x1<<" "<<y1<<" "<<x2<<" "<<y2<<" "<<x<<" "<<y<<" "<<theBarrier<<G4endl;
95 return y;
96 }
97
98 G4double G4ProtonField::GetBarrier()
99 {
100 G4double coulombBarrier = (1.44/1.14) * MeV * theZ / (1.0 + G4Pow::GetInstance()->Z13(theA));
101 //GF G4double bindingEnergy = G4NucleiPropertiesTable::GetBindingEnergy(Z, A);
102 G4double bindingEnergy =0;
103 /*
104 * G4cout << " coulombBarrier/bindingEnergy : "
105 * << coulombBarrier << " /" << bindingEnergy << G4endl;
106 */
107 return bindingEnergy/theA+coulombBarrier;
108 }
109