| Geant4 Cross Reference |
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25 //
26 // 18-Sep-2003 First version is written by T. Koi
27 // 12-Nov-2003 Add energy check at lower side T. Koi
28 // 15-Nov-2006 Above 10GeV/n Cross Section become constant T. Koi (SLAC/SCCS)
29 // 23-Dec-2006 Isotope dependence adde by D. Wright
30 // 14-Mar-2011 Moved constructor, destructor and virtual methods to source by V.Ivanchenko
31 // 19-Aug-2011 V.Ivanchenko move to new design and make x-section per element
32 //
33
34 #include "G4IonsShenCrossSection.hh"
35 #include "G4PhysicalConstants.hh"
36 #include "G4SystemOfUnits.hh"
37 #include "G4DynamicParticle.hh"
38 #include "G4NucleiProperties.hh"
39 #include "G4HadTmpUtil.hh"
40 #include "G4NistManager.hh"
41
42 G4IonsShenCrossSection::G4IonsShenCrossSection()
43 : G4VCrossSectionDataSet("IonsShen"),
44 upperLimit( 10*GeV ),
45 // lowerLimit( 10*MeV ),
46 r0 ( 1.1 )
47 {}
48
49 G4IonsShenCrossSection::~G4IonsShenCrossSection()
50 {}
51
52 void
53 G4IonsShenCrossSection::CrossSectionDescription(std::ostream& outFile) const
54 {
55 outFile << "G4IonsShenCrossSection calculates the total reaction cross\n"
56 << "section for nucleus-nucleus scattering using the Shen\n"
57 << "parameterization. It is valid for projectiles and targets of\n"
58 << "all Z, and projectile energies up to 1 TeV/n. Above 10 GeV/n"
59 << "the cross section is constant. Below 10 MeV/n zero cross\n"
60 << "is returned.\n";
61 }
62
63 G4bool G4IonsShenCrossSection::IsElementApplicable(const G4DynamicParticle* aDP,
64 G4int, const G4Material*)
65 {
66 return (1 <= aDP->GetDefinition()->GetBaryonNumber());
67 }
68
69 G4double
70 G4IonsShenCrossSection::GetElementCrossSection(const G4DynamicParticle* aParticle,
71 G4int Z,
72 const G4Material*)
73 {
74 G4int A = G4lrint(G4NistManager::Instance()->GetAtomicMassAmu(Z));
75 return GetIsoCrossSection(aParticle, Z, A);
76 }
77
78 G4double G4IonsShenCrossSection::GetIsoCrossSection(const G4DynamicParticle* aParticle,
79 G4int Zt, G4int At,
80 const G4Isotope*,
81 const G4Element*,
82 const G4Material*)
83
84 {
85 G4double xsection = 0.0;
86
87 G4int Ap = aParticle->GetDefinition()->GetBaryonNumber();
88 G4int Zp = G4lrint(aParticle->GetDefinition()->GetPDGCharge()/eplus);
89 G4double ke_per_N = aParticle->GetKineticEnergy() / Ap;
90 if ( ke_per_N > upperLimit ) { ke_per_N = upperLimit; }
91
92 // Apply energy check, if less than lower limit then 0 value is returned
93 //if ( ke_per_N < lowerLimit ) { return xsection; }
94
95 G4Pow* g4pow = G4Pow::GetInstance();
96
97 G4double cubicrAt = g4pow->Z13(At);
98 G4double cubicrAp = g4pow->Z13(Ap);
99
100 G4double Rt = 1.12 * cubicrAt - 0.94 * ( 1.0 / cubicrAt );
101 G4double Rp = 1.12 * cubicrAp - 0.94 * ( 1.0 / cubicrAp );
102
103 G4double r = Rt + Rp + 3.2; // in fm
104 G4double b = 1.0; // in MeV/fm
105 G4double targ_mass = G4NucleiProperties::GetNuclearMass(At, Zt);
106
107 G4double proj_mass = aParticle->GetMass();
108 G4double proj_momentum = aParticle->GetMomentum().mag();
109
110 G4double Ecm = calEcmValue (proj_mass, targ_mass, proj_momentum);
111
112 G4double B = 1.44 * Zt * Zp / r - b * Rt * Rp / ( Rt + Rp );
113 if(Ecm <= B) { return xsection; }
114
115 G4double c = calCeValue ( ke_per_N / MeV );
116
117 G4double R1 = r0 * (cubicrAt + cubicrAp + 1.85*cubicrAt*cubicrAp/(cubicrAt + cubicrAp) - c);
118
119 G4double R2 = 1.0 * ( At - 2 * Zt ) * Zp / ( Ap * At );
120
121
122 G4double R3 = (0.176 / g4pow->A13(Ecm)) * cubicrAt * cubicrAp /(cubicrAt + cubicrAp);
123
124 G4double R = R1 + R2 + R3;
125
126 xsection = 10 * pi * R * R * ( 1 - B / Ecm );
127 xsection = xsection * millibarn; // mulitply xsection by millibarn
128
129 return xsection;
130 }
131
132 G4double
133 G4IonsShenCrossSection::calEcmValue(const G4double mp, const G4double mt,
134 const G4double Plab)
135 {
136 G4double Elab = std::sqrt ( mp * mp + Plab * Plab );
137 G4double Ecm = std::sqrt ( mp * mp + mt * mt + 2 * Elab * mt );
138 G4double Pcm = Plab * mt / Ecm;
139 G4double KEcm = std::sqrt ( Pcm * Pcm + mp * mp ) - mp;
140 return KEcm;
141 }
142
143
144 G4double G4IonsShenCrossSection::calCeValue(const G4double ke)
145 {
146 // Calculate c value
147 // This value is indepenent from projectile and target particle
148 // ke is projectile kinetic energy per nucleon in the Lab system
149 // with MeV unit
150 // fitting function is made by T. Koi
151 // There are no data below 30 MeV/n in Kox et al.,
152
153 G4double Ce;
154 G4double log10_ke = std::log10 ( ke );
155 if (log10_ke > 1.5)
156 {
157 Ce = -10.0/std::pow(G4double(log10_ke), G4double(5)) + 2.0;
158 }
159 else
160 {
161 Ce = (-10.0/std::pow(G4double(1.5), G4double(5) ) + 2.0) /
162 std::pow(G4double(1.5) , G4double(3)) * std::pow(G4double(log10_ke), G4double(3));
163 }
164 return Ce;
165 }
166
167