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27 // -------------------------------------------------------------------
28 //
29 // GEANT4 Class file
30 //
31 //
32 // File name: G4BGGPionElasticXS
33 //
34 // Author: Vladimir Ivanchenko
35 //
36 // Creation date: 01.10.2003
37 // Modifications:
38 //
39 // -------------------------------------------------------------------
40 //
41
42 #include "G4BGGPionElasticXS.hh"
43 #include "G4SystemOfUnits.hh"
44 #include "G4ComponentGGHadronNucleusXsc.hh"
45 #include "G4UPiNuclearCrossSection.hh"
46 #include "G4HadronNucleonXsc.hh"
47 #include "G4NuclearRadii.hh"
48
49 #include "G4Proton.hh"
50 #include "G4PionPlus.hh"
51 #include "G4PionMinus.hh"
52 #include "G4NistManager.hh"
53 #include "G4HadronicParameters.hh"
54 #include "G4Pow.hh"
55
56 G4double G4BGGPionElasticXS::theGlauberFacPiPlus[93] = {0.0};
57 G4double G4BGGPionElasticXS::theCoulombFacPiPlus[93] = {0.0};
58 G4double G4BGGPionElasticXS::theGlauberFacPiMinus[93] = {0.0};
59 G4double G4BGGPionElasticXS::theCoulombFacPiMinus[93] = {0.0};
60 G4int G4BGGPionElasticXS::theA[93] = {0};
61
62 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
63
64 G4BGGPionElasticXS::G4BGGPionElasticXS(const G4ParticleDefinition* p)
65 : G4VCrossSectionDataSet("BarashenkovGlauberGribov")
66 {
67 verboseLevel = 0;
68 fGlauberEnergy = 91.*CLHEP::GeV;
69 fLowEnergy = 20.*CLHEP::MeV;
70 fLowestEnergy = 1.*CLHEP::MeV;
71 SetMinKinEnergy(0.0);
72 SetMaxKinEnergy( G4HadronicParameters::Instance()->GetMaxEnergy() );
73
74 fPion = new G4UPiNuclearCrossSection();
75 fGlauber = new G4ComponentGGHadronNucleusXsc();
76 fHadron = new G4HadronNucleonXsc();
77
78 fG4pow = G4Pow::GetInstance();
79
80 theProton = G4Proton::Proton();
81 thePiPlus = G4PionPlus::PionPlus();
82 isPiplus = (p == thePiPlus);
83 SetForAllAtomsAndEnergies(true);
84
85 if (0 == theA[0]) { Initialise(); }
86 }
87
88 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
89
90 G4BGGPionElasticXS::~G4BGGPionElasticXS()
91 {
92 delete fHadron;
93 }
94
95 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
96
97 G4bool
98 G4BGGPionElasticXS::IsElementApplicable(const G4DynamicParticle*, G4int,
99 const G4Material*)
100 {
101 return true;
102 }
103
104 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
105
106 G4bool G4BGGPionElasticXS::IsIsoApplicable(const G4DynamicParticle*,
107 G4int Z, G4int,
108 const G4Element*, const G4Material*)
109 {
110 return (1 == Z);
111 }
112
113 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
114
115 G4double
116 G4BGGPionElasticXS::GetElementCrossSection(const G4DynamicParticle* dp,
117 G4int ZZ, const G4Material*)
118 {
119 // this method should be called only for Z > 1
120 G4double cross = 0.0;
121 G4double ekin = std::max(dp->GetKineticEnergy(), fLowestEnergy);
122 G4int Z = std::min(ZZ, 92);
123 if(1 == Z) {
124 cross = 1.0115*GetIsoCrossSection(dp,1,1);
125 } else {
126 if(ekin <= fLowEnergy) {
127 cross = (isPiplus) ? theCoulombFacPiPlus[Z]*CoulombFactorPiPlus(ekin, Z)
128 : theCoulombFacPiMinus[Z]*FactorPiMinus(ekin);
129 } else if(ekin > fGlauberEnergy) {
130 cross = (isPiplus) ? theGlauberFacPiPlus[Z] : theGlauberFacPiMinus[Z];
131 cross *= fGlauber->GetElasticGlauberGribov(dp, Z, theA[Z]);
132 } else {
133 cross = fPion->GetElasticCrossSection(dp, Z, theA[Z]);
134 }
135 }
136 #ifdef G4VERBOSE
137 if(verboseLevel > 1) {
138 G4cout << "G4BGGPionElasticXS::GetElementCrossSection for "
139 << dp->GetDefinition()->GetParticleName()
140 << " Ekin(GeV)= " << dp->GetKineticEnergy()
141 << " in nucleus Z= " << Z << " A= " << theA[Z]
142 << " XS(b)= " << cross/barn
143 << G4endl;
144 }
145 #endif
146 return cross;
147 }
148
149 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
150
151 G4double
152 G4BGGPionElasticXS::GetIsoCrossSection(const G4DynamicParticle* dp,
153 G4int, G4int A,
154 const G4Isotope*,
155 const G4Element*,
156 const G4Material*)
157 {
158 // this method should be called only for Z = 1
159 fHadron->HadronNucleonXscNS(dp->GetDefinition(), theProton,
160 dp->GetKineticEnergy());
161 G4double cross = A*fHadron->GetElasticHadronNucleonXsc();
162
163 #ifdef G4VERBOSE
164 if(verboseLevel > 1) {
165 G4cout << "G4BGGPionElasticXS::GetIsoCrossSection for "
166 << dp->GetDefinition()->GetParticleName()
167 << " Ekin(GeV)= " << dp->GetKineticEnergy()
168 << " in nucleus Z=1 A=" << A
169 << " XS(b)= " << cross/barn
170 << G4endl;
171 }
172 #endif
173 return cross;
174 }
175
176 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
177
178 void G4BGGPionElasticXS::BuildPhysicsTable(const G4ParticleDefinition& p)
179 {
180 if(verboseLevel > 1) {
181 G4cout << "G4BGGPionElasticXS::BuildPhysicsTable for "
182 << p.GetParticleName() << G4endl;
183 }
184 if(&p == G4PionPlus::PionPlus() || &p == G4PionMinus::PionMinus()) {
185 isPiplus = (&p == G4PionPlus::PionPlus());
186 } else {
187 G4ExceptionDescription ed;
188 ed << "This BGG cross section is applicable only to pions and not to "
189 << p.GetParticleName() << G4endl;
190 G4Exception("G4BGGPionElasticXS::BuildPhysicsTable", "had001",
191 FatalException, ed);
192 }
193 }
194
195 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
196
197 void G4BGGPionElasticXS::Initialise()
198 {
199 theA[0] = theA[1] = 1;
200 G4ThreeVector mom(0.0,0.0,1.0);
201 G4DynamicParticle dp(thePiPlus, mom, fGlauberEnergy);
202
203 G4NistManager* nist = G4NistManager::Instance();
204
205 G4double csup, csdn;
206 for (G4int iz=2; iz<93; ++iz) {
207
208 G4int A = G4lrint(nist->GetAtomicMassAmu(iz));
209 theA[iz] = A;
210
211 csup = fGlauber->GetElasticGlauberGribov(&dp, iz, A);
212 csdn = fPion->GetElasticCrossSection(&dp, iz, A);
213 theGlauberFacPiPlus[iz] = csdn/csup;
214 }
215
216 dp.SetDefinition(G4PionMinus::PionMinus());
217 for (G4int iz=2; iz<93; ++iz) {
218 csup = fGlauber->GetElasticGlauberGribov(&dp, iz, theA[iz]);
219 csdn = fPion->GetElasticCrossSection(&dp, iz, theA[iz]);
220 theGlauberFacPiMinus[iz] = csdn/csup;
221
222 if (verboseLevel > 1) {
223 G4cout << "Z= " << iz << " A= " << theA[iz]
224 << " factorPiPlus= " << theGlauberFacPiPlus[iz]
225 << " factorPiMinus= " << theGlauberFacPiMinus[iz]
226 << G4endl;
227 }
228 }
229 theCoulombFacPiPlus[1] = 1.0;
230 theCoulombFacPiMinus[1]= 1.0;
231 dp.SetKineticEnergy(fLowEnergy);
232 dp.SetDefinition(thePiPlus);
233 for (G4int iz=2; iz<93; ++iz) {
234 theCoulombFacPiPlus[iz] = fPion->GetElasticCrossSection(&dp, iz, theA[iz])
235 /CoulombFactorPiPlus(fLowEnergy, iz);
236 }
237 dp.SetDefinition(G4PionMinus::PionMinus());
238 for(G4int iz=2; iz<93; ++iz) {
239 theCoulombFacPiMinus[iz] = fPion->GetElasticCrossSection(&dp, iz, theA[iz])
240 /FactorPiMinus(fLowEnergy);
241
242 if(verboseLevel > 1) {
243 G4cout << "Z= " << iz << " A= " << theA[iz]
244 << " CoulombFactorPiPlus= " << theCoulombFacPiPlus[iz]
245 << " CoulombFactorPiMinus= " << theCoulombFacPiMinus[iz]
246 << G4endl;
247 }
248 }
249 }
250
251 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
252
253 G4double G4BGGPionElasticXS::CoulombFactorPiPlus(G4double kinEnergy, G4int Z)
254 {
255 return (kinEnergy > 0.0) ?
256 G4NuclearRadii::CoulombFactor(Z, theA[Z], thePiPlus, kinEnergy) : 0.0;
257 }
258
259 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
260
261 G4double G4BGGPionElasticXS::FactorPiMinus(G4double kinEnergy)
262 {
263 return 1.0/std::sqrt(kinEnergy);
264 }
265
266 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
267
268 void
269 G4BGGPionElasticXS::CrossSectionDescription(std::ostream& outFile) const
270 {
271 outFile << "The Barashenkov-Glauber-Gribov cross section handles elastic\n"
272 << "scattering of pions from nuclei at all energies. The\n"
273 << "Barashenkov parameterization is used below 91 GeV and the\n"
274 << "Glauber-Gribov parameterization is used above 91 GeV.\n";
275 }
276
277 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
278