ECCE @ EIC Software
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Macros Groups Pages
G4IonCoulombCrossSection.cc
Go to the documentation of this file. Or view the newest version in sPHENIX GitHub for file G4IonCoulombCrossSection.cc
1 //
2 // ********************************************************************
3 // * License and Disclaimer *
4 // * *
5 // * The Geant4 software is copyright of the Copyright Holders of *
6 // * the Geant4 Collaboration. It is provided under the terms and *
7 // * conditions of the Geant4 Software License, included in the file *
8 // * LICENSE and available at http://cern.ch/geant4/license . These *
9 // * include a list of copyright holders. *
10 // * *
11 // * Neither the authors of this software system, nor their employing *
12 // * institutes,nor the agencies providing financial support for this *
13 // * work make any representation or warranty, express or implied, *
14 // * regarding this software system or assume any liability for its *
15 // * use. Please see the license in the file LICENSE and URL above *
16 // * for the full disclaimer and the limitation of liability. *
17 // * *
18 // * This code implementation is the result of the scientific and *
19 // * technical work of the GEANT4 collaboration. *
20 // * By using, copying, modifying or distributing the software (or *
21 // * any work based on the software) you agree to acknowledge its *
22 // * use in resulting scientific publications, and indicate your *
23 // * acceptance of all terms of the Geant4 Software license. *
24 // ********************************************************************
25 //
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....
56 
58 #include "G4PhysicalConstants.hh"
59 #include "Randomize.hh"
60 #include "G4Proton.hh"
61 #include "G4Exp.hh"
62 #include "G4Log.hh"
63 
64 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
65 
66 using namespace std;
67 
69 
71  cosThetaMin(1.0),
72  cosThetaMax(-1.0),
74 {
78  particle=0;
79 
81  coeff = twopi*p0*p0;
82 
83  cosTetMinNuc=0;
84  cosTetMaxNuc=0;
85  nucXSection =0;
86 
87  chargeSquare = spin = mass = 0.0;
88  tkinLab = momLab2 = invbetaLab2 = tkin = mom2 = invbeta2 = 0.0;
89 
91 }
92 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
93 
95 {}
96 
97 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
98 
100  G4double CosThetaLim)
101 {
102  SetupParticle(p);
103  nucXSection = tkin = targetZ = mom2 = 0.0;
104  etag = DBL_MAX;
105  particle = p;
106  cosThetaMin = CosThetaLim;
107 }
108 
109 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
110 
112 {
113  if(ekin != tkinLab || tmass != targetMass) {
114 
115  // lab
116  tkinLab = ekin;
117  momLab2 = tkinLab*(tkinLab + 2.0*mass);
118  invbetaLab2 = 1.0 + mass*mass/momLab2;
119 
120  G4double etot = tkinLab + mass;
121  G4double ptot = sqrt(momLab2);
122  G4double m12 = mass*mass;
123  // relativistic reduced mass from publucation
124  // A.P. Martynenko, R.N. Faustov, Teoret. mat. Fiz. 64 (1985) 179
125 
126  //incident particle & target nucleus
127  targetMass = tmass;
128  G4double Ecm=sqrt(m12 + targetMass*targetMass + 2.0*etot*targetMass);
129  G4double mu_rel=mass*targetMass/Ecm;
130  G4double momCM= ptot*targetMass/Ecm;
131  // relative system
132  mom2 = momCM*momCM;
133  invbeta2 = 1.0 + mu_rel*mu_rel/mom2;
134  tkin = momCM*sqrt(invbeta2) - mu_rel;//Ekin of mu_rel
135 
138  }
139 }
140 
141 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
142 
144  G4int)
145 {
146  if(Z != targetZ || e != etag) {
147  etag = e;
148  targetZ = Z;
149  G4int iz= G4lrint(Z);
150 
151  SetScreenRSquare(iz);
152  screenZ = 0;
154  //heavycorr = 0;
155  // G4cout<< "heavycorr "<<heavycorr<<G4endl;
156 
157  G4double corr=5.*twopi*Z*std::sqrt(chargeSquare*alpha2);
158  corr=G4Exp(G4Log(corr)*0.04);
159  screenZ *=0.5*(1.13 + corr*3.76*Z*Z*chargeSquare*invbeta2*alpha2);
160  // G4cout<<" heavycorr Z e corr....2As "<< heavycorr << "\t"
161  // <<Z <<"\t"<<e/MeV <<"\t"<<screenZ<<G4endl;
162 
163  if(1 == iz && particle == theProton && cosTetMaxNuc < 0.0) {
164  cosTetMaxNuc = 0.0;
165  }
166  }
167 }
168 
169 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
170 
172 {
173  //for proton Thomas-Fermi screening length
174  G4int Z1 = G4lrint(std::sqrt(chargeSquare));
175  G4double Z113 = fG4pow->Z13(iz);
176  G4double Z1023 = fG4pow->powZ(Z1,0.23);
177  G4double Z2023 = fG4pow->powZ(iz,0.23);
178  G4double x=a0*(Z1023+Z2023);
179 
180  // Universal screening length
181  if(particle == theProton){
182  x = a0*Z113;
183  }
184 
185  ScreenRSquare = alpha2*x*x;
186 }
187 
188 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
189 
191 {
192  // This method needs initialisation before be called
193  // scattering with target nucleus
195 
196  nucXSection = 0.0;
197 
198  G4double x = 1.0 - cosTetMinNuc;
199  G4double x1 = x + screenZ;
200 
201  // scattering with nucleus
202  if(cosTetMaxNuc < cosTetMinNuc) {
203  nucXSection = fac*(cosTetMinNuc - cosTetMaxNuc)/
204  (x1*(1.0 - cosTetMaxNuc + screenZ));
205  }
206 
207  return nucXSection;
208 }
209 
210 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
211 
213 {
214  G4double z1 = 0.0;
215  if(cosTetMaxNuc < cosTetMinNuc) {
216 
217  G4double x1 = 1. - cosTetMinNuc + screenZ;
218  G4double x2 = 1. - cosTetMaxNuc + screenZ;
220  z1 = x1*x2/(x1 + G4UniformRand()*dx) - screenZ;
221  }
222  return z1;
223 }
224 
225 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
226 
227 
228 
229