source: trunk/source/processes/hadronic/cross_sections/src/G4BGGPionElasticXS.cc@ 1340

Last change on this file since 1340 was 1340, checked in by garnier, 15 years ago

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25//
26// $Id: G4BGGPionElasticXS.cc,v 1.8 2010/10/12 06:03:37 dennis Exp $
27// GEANT4 tag $Name: hadr-cross-V09-03-12 $
28//
29// -------------------------------------------------------------------
30//
31// GEANT4 Class file
32//
33//
34// File name: G4BGGPionElasticXS
35//
36// Author: Vladimir Ivanchenko
37//
38// Creation date: 01.10.2003
39// Modifications:
40//
41//
42// -------------------------------------------------------------------
43//
44
45#include "G4BGGPionElasticXS.hh"
46#include "G4GlauberGribovCrossSection.hh"
47#include "G4UPiNuclearCrossSection.hh"
48#include "G4HadronNucleonXsc.hh"
49#include "G4PionPlus.hh"
50#include "G4PionMinus.hh"
51#include "G4NistManager.hh"
52
53//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
54
55G4BGGPionElasticXS::G4BGGPionElasticXS(const G4ParticleDefinition*)
56{
57 verboseLevel = 0;
58 fGlauberEnergy = 91.*GeV;
59 fLowEnergy = 20.*MeV;
60 fPion = 0;
61 fGlauber = 0;
62 fHadron = 0;
63 particle = 0;
64 isPiplus = false;
65 isInitialized = false;
66}
67
68//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
69
70G4BGGPionElasticXS::~G4BGGPionElasticXS()
71{
72 delete fGlauber;
73 delete fPion;
74 delete fHadron;
75}
76
77//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
78
79G4double
80G4BGGPionElasticXS::GetZandACrossSection(const G4DynamicParticle* dp,
81 G4int Z, G4int A, G4double)
82{
83 G4double cross = 0.0;
84 G4double ekin = dp->GetKineticEnergy();
85// G4int iz = G4int(Z);
86 if(Z > 92) Z = 92;
87
88 if(ekin <= fLowEnergy) {
89 cross = theCoulombFac[Z];
90 if(isPiplus) { cross *= CoulombFactor(ekin, A); }
91
92 } else if(Z == 1) {
93 if( A < 2) {
94 fHadron->GetHadronNucleonXscNS(dp, G4Proton::Proton());
95 cross = fHadron->GetElasticHadronNucleonXsc();
96 } else {
97 fHadron->GetHadronNucleonXscNS(dp, G4Proton::Proton());
98 cross = fHadron->GetElasticHadronNucleonXsc();
99 fHadron->GetHadronNucleonXscNS(dp, G4Neutron::Neutron());
100 cross += fHadron->GetElasticHadronNucleonXsc();
101 }
102 } else if(ekin > fGlauberEnergy) {
103 cross = theGlauberFac[Z]*fGlauber->GetElasticGlauberGribov(dp, Z, A);
104 } else {
105 cross = fPion->GetElasticCrossSection(dp, Z, A);
106 }
107
108 if(verboseLevel > 1)
109 G4cout << "G4BGGPionElasticXS::GetCrossSection for "
110 << dp->GetDefinition()->GetParticleName()
111 << " Ekin(GeV)= " << dp->GetKineticEnergy()
112 << " in nucleus Z= " << Z << " A= " << A
113 << " XS(b)= " << cross/barn
114 << G4endl;
115
116 return cross;
117}
118
119//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
120
121void G4BGGPionElasticXS::BuildPhysicsTable(const G4ParticleDefinition& p)
122{
123 if(&p == G4PionPlus::PionPlus() || &p == G4PionMinus::PionMinus()) {
124 particle = &p;
125 Initialise();
126 } else {
127 G4cout << "### G4BGGPionElasticXS WARNING: is not applicable to "
128 << p.GetParticleName()
129 << G4endl;
130 }
131}
132
133//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
134
135void G4BGGPionElasticXS::DumpPhysicsTable(const G4ParticleDefinition&)
136{
137 G4cout << "G4BGGPionElasticXS:"<<G4endl;
138}
139
140//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
141
142void G4BGGPionElasticXS::Initialise()
143{
144 if(isInitialized) return;
145 isInitialized = true;
146
147 fPion = new G4UPiNuclearCrossSection();
148 fGlauber = new G4GlauberGribovCrossSection();
149 fHadron = new G4HadronNucleonXsc();
150 fPion->BuildPhysicsTable(*particle);
151 fGlauber->BuildPhysicsTable(*particle);
152 if(particle == G4PionPlus::PionPlus()) isPiplus = true;
153
154 G4ParticleDefinition* part = const_cast<G4ParticleDefinition*>(particle);
155 G4ThreeVector mom(0.0,0.0,1.0);
156 G4DynamicParticle dp(part, mom, fGlauberEnergy);
157
158 G4NistManager* nist = G4NistManager::Instance();
159
160 G4double csup, csdn;
161 G4int A;
162
163 if(verboseLevel > 0) G4cout << "### G4BGGPionElasticXS::Initialise for "
164 << particle->GetParticleName() << G4endl;
165
166 for(G4int iz=2; iz<93; iz++) {
167
168 G4double Z = G4double(iz);
169 A = G4lrint(nist->GetAtomicMassAmu(iz));
170
171 csup = fGlauber->GetElasticGlauberGribov(&dp, iz, A);
172 csdn = fPion->GetElasticCrossSection(&dp, iz, A);
173
174 theGlauberFac[iz] = csdn/csup;
175 if(verboseLevel > 0) G4cout << "Z= " << Z << " A= " << A
176 << " factor= " << theGlauberFac[iz] << G4endl;
177 }
178 dp.SetKineticEnergy(fLowEnergy);
179 fHadron->GetHadronNucleonXscNS(&dp, G4Proton::Proton());
180 theCoulombFac[1] = fHadron->GetElasticHadronNucleonXsc();
181 if(isPiplus) { theCoulombFac[1] /= CoulombFactor(fLowEnergy,1); }
182
183 for(G4int iz=2; iz<93; iz++) {
184
185 G4double Z = G4double(iz);
186 A = G4lrint(nist->GetAtomicMassAmu(iz));
187
188 theCoulombFac[iz] = fPion->GetElasticCrossSection(&dp, iz, A);
189 if(isPiplus) { theCoulombFac[iz] /= CoulombFactor(fLowEnergy,A); }
190 if(verboseLevel > 0) G4cout << "Z= " << Z << " A= " << A
191 << " factor= " << theCoulombFac[iz] << G4endl;
192 }
193}
194
195
196G4double G4BGGPionElasticXS::CoulombFactor(G4double kinEnergy, G4int A)
197{
198 G4double res= 0.0;
199 if(kinEnergy <= DBL_MIN) return res;
200 else if(A < 2) return kinEnergy*kinEnergy;
201
202 G4double elog = std::log10(kinEnergy/GeV);
203 G4double aa = A;
204
205 // from G4ProtonInelasticCrossSection
206 G4double f1 = 8.0 - 8.0/aa - 0.008*aa;
207 G4double f2 = 2.34 - 5.4/aa - 0.0028*aa;
208
209 res = 1.0/(1.0 + std::exp(-f1*(elog + f2)));
210
211 f1 = 5.6 - 0.016*aa;
212 f2 = 1.37 + 1.37/aa;
213 res *= ( 1.0 + (0.8 + 18./aa - 0.002*aa)/(1.0 + std::exp(f1*(elog + f2))));
214 return res;
215}
216
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