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25 // 25 //
26 // G4IonCoulombCrossSection.cc 26 // G4IonCoulombCrossSection.cc
27 //-------------------------------------------- 27 //-------------------------------------------------------------------
28 // 28 //
29 // GEANT4 Class header file 29 // GEANT4 Class header file
30 // 30 //
31 // File name: G4IonCoulombCrossSection 31 // File name: G4IonCoulombCrossSection
32 // 32 //
33 // Author: Cristina Consolandi 33 // Author: Cristina Consolandi
34 // 34 //
35 // Creation date: 05.10.2010 from G4eCoulombSc 35 // Creation date: 05.10.2010 from G4eCoulombScatteringModel
36 // 36 //
37 // Class Description: 37 // Class Description:
38 // Computation of Screen-Coulomb Cross Sectio 38 // Computation of Screen-Coulomb Cross Section
39 // for protons, alpha and heavy Ions 39 // for protons, alpha and heavy Ions
40 // 40 //
41 // 41 //
42 // Reference: 42 // Reference:
43 // M.J. Boschini et al. "Nuclear and Non- 43 // M.J. Boschini et al. "Nuclear and Non-Ionizing Energy-Loss
44 // for Coulomb Scattered Particles from L 44 // for Coulomb Scattered Particles from Low Energy up to Relativistic
45 // Regime in Space Radiation Environment" 45 // Regime in Space Radiation Environment"
46 // Accepted for publication in the Procee 46 // Accepted for publication in the Proceedings of the ICATPP Conference
47 // on Cosmic Rays for Particle and Astrop 47 // on Cosmic Rays for Particle and Astroparticle Physics, Villa Olmo, 7-8
48 // October, 2010, to be published by Wor 48 // October, 2010, to be published by World Scientific (Singapore).
49 // 49 //
50 // Available for downloading at: 50 // Available for downloading at:
51 // http://arxiv.org/abs/1011.4822 51 // http://arxiv.org/abs/1011.4822
52 // 52 //
53 // ------------------------------------------- 53 // -------------------------------------------------------------------
54 // 54 //
55 //....oooOO0OOooo........oooOO0OOooo........oo 55 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
56 56
57 #include "G4IonCoulombCrossSection.hh" 57 #include "G4IonCoulombCrossSection.hh"
58 #include "G4PhysicalConstants.hh" 58 #include "G4PhysicalConstants.hh"
59 #include "Randomize.hh" 59 #include "Randomize.hh"
60 #include "G4Proton.hh" 60 #include "G4Proton.hh"
61 #include "G4Exp.hh" 61 #include "G4Exp.hh"
62 #include "G4Log.hh" 62 #include "G4Log.hh"
63 63
64 //....oooOO0OOooo........oooOO0OOooo........oo 64 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
65 65
66 using namespace std; 66 using namespace std;
67 67
68 const G4double a0 = CLHEP::electron_mass_c2/0. 68 const G4double a0 = CLHEP::electron_mass_c2/0.88534;
69 69
70 G4IonCoulombCrossSection::G4IonCoulombCrossSec 70 G4IonCoulombCrossSection::G4IonCoulombCrossSection():
71 cosThetaMin(1.0), 71 cosThetaMin(1.0),
72 cosThetaMax(-1.0), 72 cosThetaMax(-1.0),
73 alpha2(fine_structure_const*fine_structure_ 73 alpha2(fine_structure_const*fine_structure_const)
74 { 74 {
75 fNistManager = G4NistManager::Instance(); 75 fNistManager = G4NistManager::Instance();
76 fG4pow = G4Pow::GetInstance(); 76 fG4pow = G4Pow::GetInstance();
77 theProton = G4Proton::Proton(); 77 theProton = G4Proton::Proton();
78 particle = nullptr; 78 particle = nullptr;
79 79
80 G4double p0 = electron_mass_c2*classic_elect 80 G4double p0 = electron_mass_c2*classic_electr_radius;
81 coeff = twopi*p0*p0; 81 coeff = twopi*p0*p0;
82 82
83 cosTetMinNuc=0; 83 cosTetMinNuc=0;
84 cosTetMaxNuc=0; 84 cosTetMaxNuc=0;
85 nucXSection =0; 85 nucXSection =0;
86 86
87 chargeSquare = spin = mass = 0.0; 87 chargeSquare = spin = mass = 0.0;
88 tkinLab = momLab2 = invbetaLab2 = tkin = mom 88 tkinLab = momLab2 = invbetaLab2 = tkin = mom2 = invbeta2 = 0.0;
89 89
90 targetZ = targetMass = screenZ = ScreenRSqua 90 targetZ = targetMass = screenZ = ScreenRSquare = etag = 0.0;
91 } 91 }
92 92
93 //....oooOO0OOooo........oooOO0OOooo........oo 93 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
94 94
95 void G4IonCoulombCrossSection::Initialise(cons 95 void G4IonCoulombCrossSection::Initialise(const G4ParticleDefinition* p,
96 G4do 96 G4double CosThetaLim)
97 { 97 {
98 SetupParticle(p); 98 SetupParticle(p);
99 nucXSection = tkin = targetZ = mom2 = 0.0; 99 nucXSection = tkin = targetZ = mom2 = 0.0;
100 etag = DBL_MAX; 100 etag = DBL_MAX;
101 particle = p; 101 particle = p;
102 cosThetaMin = CosThetaLim; 102 cosThetaMin = CosThetaLim;
103 } 103 }
104 104
105 //....oooOO0OOooo........oooOO0OOooo........oo 105 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
106 106
107 void G4IonCoulombCrossSection::SetupKinematic( 107 void G4IonCoulombCrossSection::SetupKinematic(G4double ekin, G4double tmass)
108 { 108 {
109 if(ekin != tkinLab || tmass != targetMass) { 109 if(ekin != tkinLab || tmass != targetMass) {
110 110
111 // lab 111 // lab
112 tkinLab = ekin; 112 tkinLab = ekin;
113 momLab2 = tkinLab*(tkinLab + 2.0*mass); 113 momLab2 = tkinLab*(tkinLab + 2.0*mass);
114 invbetaLab2 = 1.0 + mass*mass/momLab2; 114 invbetaLab2 = 1.0 + mass*mass/momLab2;
115 115
116 G4double etot = tkinLab + mass; 116 G4double etot = tkinLab + mass;
117 G4double ptot = sqrt(momLab2); 117 G4double ptot = sqrt(momLab2);
118 G4double m12 = mass*mass; 118 G4double m12 = mass*mass;
119 // relativistic reduced mass from publucat 119 // relativistic reduced mass from publucation
120 // A.P. Martynenko, R.N. Faustov, Teoret. 120 // A.P. Martynenko, R.N. Faustov, Teoret. mat. Fiz. 64 (1985) 179
121 121
122 //incident particle & target nucleus 122 //incident particle & target nucleus
123 targetMass = tmass; 123 targetMass = tmass;
124 G4double Ecm=sqrt(m12 + targetMass*targetM 124 G4double Ecm=sqrt(m12 + targetMass*targetMass + 2.0*etot*targetMass);
125 G4double mu_rel=mass*targetMass/Ecm; 125 G4double mu_rel=mass*targetMass/Ecm;
126 G4double momCM= ptot*targetMass/Ecm; 126 G4double momCM= ptot*targetMass/Ecm;
127 // relative system 127 // relative system
128 mom2 = momCM*momCM; 128 mom2 = momCM*momCM;
129 invbeta2 = 1.0 + mu_rel*mu_rel/mom2; 129 invbeta2 = 1.0 + mu_rel*mu_rel/mom2;
130 tkin = momCM*sqrt(invbeta2) - mu_rel;//Eki 130 tkin = momCM*sqrt(invbeta2) - mu_rel;//Ekin of mu_rel
131 131
132 cosTetMinNuc = cosThetaMin; 132 cosTetMinNuc = cosThetaMin;
133 cosTetMaxNuc = cosThetaMax; 133 cosTetMaxNuc = cosThetaMax;
134 } 134 }
135 } 135 }
136 136
137 //....oooOO0OOooo........oooOO0OOooo........oo 137 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
138 138
139 void G4IonCoulombCrossSection::SetupTarget(G4d 139 void G4IonCoulombCrossSection::SetupTarget(G4double Z, G4double e,
140 G4int) 140 G4int)
141 { 141 {
142 if(Z != targetZ || e != etag) { 142 if(Z != targetZ || e != etag) {
143 etag = e; 143 etag = e;
144 targetZ = Z; 144 targetZ = Z;
145 G4int iz= G4lrint(Z); 145 G4int iz= G4lrint(Z);
146 146
147 SetScreenRSquare(iz); 147 SetScreenRSquare(iz);
148 screenZ = 0; 148 screenZ = 0;
149 screenZ = ScreenRSquare/mom2; 149 screenZ = ScreenRSquare/mom2;
150 //heavycorr = 0; 150 //heavycorr = 0;
151 // G4cout<< "heavycorr "<<heavycorr<<G4en 151 // G4cout<< "heavycorr "<<heavycorr<<G4endl;
152 152
153 G4double corr=5.*twopi*Z*std::sqrt(chargeS 153 G4double corr=5.*twopi*Z*std::sqrt(chargeSquare*alpha2);
154 corr=G4Exp(G4Log(corr)*0.04); 154 corr=G4Exp(G4Log(corr)*0.04);
155 screenZ *=0.5*(1.13 + corr*3.76*Z*Z*charge 155 screenZ *=0.5*(1.13 + corr*3.76*Z*Z*chargeSquare*invbeta2*alpha2);
156 // G4cout<<" heavycorr Z e corr....2As "<< 156 // G4cout<<" heavycorr Z e corr....2As "<< heavycorr << "\t"
157 // <<Z <<"\t"<<e/MeV <<"\t"<<screenZ<<G4e 157 // <<Z <<"\t"<<e/MeV <<"\t"<<screenZ<<G4endl;
158 158
159 if(1 == iz && particle == theProton && cos 159 if(1 == iz && particle == theProton && cosTetMaxNuc < 0.0) {
160 cosTetMaxNuc = 0.0; 160 cosTetMaxNuc = 0.0;
161 } 161 }
162 } 162 }
163 } 163 }
164 164
165 //....oooOO0OOooo........oooOO0OOooo........oo 165 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
166 166
167 void G4IonCoulombCrossSection::SetScreenRSquar 167 void G4IonCoulombCrossSection::SetScreenRSquare(G4int iz)
168 { 168 {
169 //for proton Thomas-Fermi screening length 169 //for proton Thomas-Fermi screening length
170 G4int Z1 = G4lrint(std::sqrt(chargeSquare)); 170 G4int Z1 = G4lrint(std::sqrt(chargeSquare));
171 G4double Z113 = fG4pow->Z13(iz); 171 G4double Z113 = fG4pow->Z13(iz);
172 G4double Z1023 = fG4pow->powZ(Z1,0.23); 172 G4double Z1023 = fG4pow->powZ(Z1,0.23);
173 G4double Z2023 = fG4pow->powZ(iz,0.23); 173 G4double Z2023 = fG4pow->powZ(iz,0.23);
174 G4double x=a0*(Z1023+Z2023); 174 G4double x=a0*(Z1023+Z2023);
175 175
176 // Universal screening length 176 // Universal screening length
177 if(particle == theProton){ 177 if(particle == theProton){
178 x = a0*Z113; 178 x = a0*Z113;
179 } 179 }
180 180
181 ScreenRSquare = alpha2*x*x; 181 ScreenRSquare = alpha2*x*x;
182 } 182 }
183 183
184 //....oooOO0OOooo........oooOO0OOooo........oo 184 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
185 185
186 G4double G4IonCoulombCrossSection::NuclearCros 186 G4double G4IonCoulombCrossSection::NuclearCrossSection()
187 { 187 {
188 // This method needs initialisation before b 188 // This method needs initialisation before be called
189 // scattering with target nucleus 189 // scattering with target nucleus
190 G4double fac = coeff*targetZ*(targetZ)*charg 190 G4double fac = coeff*targetZ*(targetZ)*chargeSquare*invbeta2/mom2;
191 191
192 nucXSection = 0.0; 192 nucXSection = 0.0;
193 193
194 G4double x = 1.0 - cosTetMinNuc; 194 G4double x = 1.0 - cosTetMinNuc;
195 G4double x1 = x + screenZ; 195 G4double x1 = x + screenZ;
196 196
197 // scattering with nucleus 197 // scattering with nucleus
198 if(cosTetMaxNuc < cosTetMinNuc) { 198 if(cosTetMaxNuc < cosTetMinNuc) {
199 nucXSection = fac*(cosTetMinNuc - cosTetMa 199 nucXSection = fac*(cosTetMinNuc - cosTetMaxNuc)/
200 (x1*(1.0 - cosTetMaxNuc + screenZ)); 200 (x1*(1.0 - cosTetMaxNuc + screenZ));
201 } 201 }
202 202
203 return nucXSection; 203 return nucXSection;
204 } 204 }
205 205
206 //....oooOO0OOooo........oooOO0OOooo........oo 206 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
207 207
208 G4double G4IonCoulombCrossSection::SampleCosin 208 G4double G4IonCoulombCrossSection::SampleCosineTheta()
209 { 209 {
210 G4double z1 = 0.0; 210 G4double z1 = 0.0;
211 if(cosTetMaxNuc < cosTetMinNuc) { 211 if(cosTetMaxNuc < cosTetMinNuc) {
212 212
213 G4double x1 = 1. - cosTetMinNuc + screenZ; 213 G4double x1 = 1. - cosTetMinNuc + screenZ;
214 G4double x2 = 1. - cosTetMaxNuc + screenZ; 214 G4double x2 = 1. - cosTetMaxNuc + screenZ;
215 G4double dx = cosTetMinNuc - cosTetMaxNuc; 215 G4double dx = cosTetMinNuc - cosTetMaxNuc;
216 z1 = x1*x2/(x1 + G4UniformRand()*dx) - scr 216 z1 = x1*x2/(x1 + G4UniformRand()*dx) - screenZ;
217 } 217 }
218 return z1; 218 return z1;
219 } 219 }
220 220
221 //....oooOO0OOooo........oooOO0OOooo........oo 221 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
222 222
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