Geant4  10.00.p01
G4IonCoulombCrossSection.cc
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26 // G4IonCoulombCrossSection.cc
27 //-------------------------------------------------------------------
28 //
29 // GEANT4 Class header file
30 //
31 // File name: G4IonCoulombCrossSection
32 //
33 // Author: Cristina Consolandi
34 //
35 // Creation date: 05.10.2010 from G4eCoulombScatteringModel
36 //
37 // Class Description:
38 // Computation of Screen-Coulomb Cross Section
39 // for protons, alpha and heavy Ions
40 //
41 //
42 // Reference:
43 // M.J. Boschini et al. "Nuclear and Non-Ionizing Energy-Loss
44 // for Coulomb Scattered Particles from Low Energy up to Relativistic
45 // Regime in Space Radiation Environment"
46 // Accepted for publication in the Proceedings of the ICATPP Conference
47 // on Cosmic Rays for Particle and Astroparticle Physics, Villa Olmo, 7-8
48 // October, 2010, to be published by World Scientific (Singapore).
49 //
50 // Available for downloading at:
51 // http://arxiv.org/abs/1011.4822
52 //
53 // -------------------------------------------------------------------
54 //
55 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
57 #include "G4PhysicalConstants.hh"
58 #include "Randomize.hh"
59 #include "G4Proton.hh"
60 #include "G4LossTableManager.hh"
61 
62 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
63 
64 
65 using namespace std;
66 
68  cosThetaMin(1.0),
69  cosThetaMax(-1.0),
70  alpha2(fine_structure_const*fine_structure_const)
71 {
74  particle=0;
75 
76  G4double p0 = electron_mass_c2*classic_electr_radius;
77  coeff = twopi*p0*p0;
78 
79  cosTetMinNuc=0;
80  cosTetMaxNuc=0;
81  nucXSection =0;
82 
83 
84  chargeSquare = spin = mass =0;
86  tkin = mom2 = invbeta2=0;
87 
88  targetZ = targetMass = screenZ =0;
89  ScreenRSquare=0.;
90 
91  etag = ecut = 0.0;
92 
93 }
94 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
95 
97 {}
98 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
99 
101  G4double CosThetaLim)
102 {
103 
104  SetupParticle(p);
105  nucXSection = 0.0;
106  tkin = targetZ = mom2 = DBL_MIN;
107  ecut = etag = DBL_MAX;
108  particle = p;
109 
110 
111  cosThetaMin = CosThetaLim;
112 
113 }
114 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
115 
117  G4double cut,G4int iz )
118 {
119  if(ekin != tkinLab || ecut != cut) {
120 
121  // lab
122  tkinLab = ekin;
123  momLab2 = tkinLab*(tkinLab + 2.0*mass);
124  invbetaLab2 = 1.0 + mass*mass/momLab2;
125 
126  G4double etot = tkinLab + mass;
127  G4double ptot = sqrt(momLab2);
128  G4double m12 = mass*mass;
129 
131 
132  // relativistic reduced mass from publucation
133  // A.P. Martynenko, R.N. Faustov, Teoret. mat. Fiz. 64 (1985) 179
134 
135  //incident particle & target nucleus
136  G4double Ecm=sqrt(m12 + targetMass*targetMass + 2.0*etot*targetMass);
137  G4double mu_rel=mass*targetMass/Ecm;
138  G4double momCM= ptot*targetMass/Ecm;
139  // relative system
140  mom2 = momCM*momCM;
141  invbeta2 = 1.0 + mu_rel*mu_rel/mom2;
142  tkin = momCM*sqrt(invbeta2) - mu_rel;//Ekin of mu_rel
143  //.........................................................
144 
147 
148  }
149 
150 }
151 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
152 
153 
155 {
156  if(Z != targetZ || e != etag) {
157  etag = e;
158  targetZ = Z;
159  G4int iz= G4int(Z);
160 
161  SetScreenRSquare(iz);
162  screenZ =0;
164 
165  // G4cout<< "heavycorr "<<heavycorr<<G4endl;
166 
167  if(heavycorr!=0 && particle != theProton){
168  G4double corr=5.*twopi*Z*std::sqrt(chargeSquare*alpha2);
169  corr=std::pow(corr,0.12);
170  screenZ *=(1.13 + corr*3.76*Z*Z*chargeSquare*invbeta2*alpha2)/2.;
171 // G4cout<<" heavycorr Z e corr....2As "<< heavycorr << "\t"
172 // <<Z <<"\t"<<e/MeV <<"\t"<<screenZ<<G4endl;
173 
174  }else{ screenZ *=(1.13 + 3.76*Z*Z*chargeSquare*invbeta2*alpha2)/2.;
175 // G4cout<<" heavycorr Z e....2As "<< heavycorr << "\t"
176 // <<Z <<"\t"<< e/MeV <<"\t" <<screenZ<<G4endl;
177  }
178 
179  if(1 == iz && particle == theProton && cosTetMaxNuc < 0.0) {
180  cosTetMaxNuc = 0.0;
181  }
182 
183  }
184 }
185 
186 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
188 
189  G4double a0 = electron_mass_c2/0.88534;
190 
191  //target nucleus
192  G4double Z1=std::sqrt(chargeSquare);
193  G4double Z2=targetZ;
194 
195  G4double Z1023=std::pow(Z1,0.23);
196  G4double Z2023=std::pow(Z2,0.23);
197 
198  // Universal screening length
199  G4double x=a0*(Z1023+Z2023);
200 
201  //for proton Thomas-Fermi screening length
202  if(particle == theProton){
203  x = a0*fNistManager->GetZ13(iz);
204  }
205  ScreenRSquare = alpha2*x*x;
206 
207 
208 }
209 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
210 
212 {
213  // This method needs initialisation before be called
214 
215  // scattering with target nucleus
217 
218  nucXSection = 0.0;
219 
220  G4double x = 1.0 - cosTetMinNuc;
221  G4double x1 = x + screenZ;
222 
223  // scattering with nucleus
224  if(cosTetMaxNuc < cosTetMinNuc) {
225 
227  (x1*(1.0 - cosTetMaxNuc + screenZ));
228 
229  }
230 
231  return nucXSection;
232 }
233 
234 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
235 
237 {
238 
239  if(cosTetMaxNuc >= cosTetMinNuc) return 0.0;
240 
241  G4double x1 = 1. - cosTetMinNuc + screenZ;
242  G4double x2 = 1. - cosTetMaxNuc + screenZ;
244  G4double /*grej,*/ z1;
245 
246  z1 = x1*x2/(x1 + G4UniformRand()*dx) - screenZ;
247  //grej = 1.0/(1.0 + z1);
248  return z1;
249 }
250 
251 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
252 
253 
254 
255 
void SetupTarget(G4double Z, G4double kinEnergy, G4int heavycorr)
static const G4double a0
static const G4double fac
G4double GetZ13(G4double Z)
const G4ParticleDefinition * theProton
int G4int
Definition: G4Types.hh:78
static G4NistManager * Instance()
const G4ParticleDefinition * particle
#define G4UniformRand()
Definition: Randomize.hh:87
void SetupParticle(const G4ParticleDefinition *)
G4double iz
Definition: TRTMaterials.hh:39
static G4Proton * Proton()
Definition: G4Proton.cc:93
#define DBL_MIN
Definition: templates.hh:75
G4double GetAtomicMassAmu(const G4String &symb) const
double G4double
Definition: G4Types.hh:76
#define DBL_MAX
Definition: templates.hh:83
void Initialise(const G4ParticleDefinition *, G4double cosThetaLim)
void SetupKinematic(G4double kinEnergy, G4double cut, G4int iz)