Geant4  10.02
G4PolarizedBremsstrahlungCrossSection.cc
Go to the documentation of this file.
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 // $Id: G4PolarizedBremsstrahlungCrossSection.cc 77295 2013-11-22 11:02:41Z gcosmo $
27 //
28 // -------------------------------------------------------------------
29 //
30 // GEANT4 Class file
31 //
32 //
33 // File name: G4PolarizedBremsstrahlungCrossSection
34 //
35 // Author: Andreas Schaelicke on the base of Karim Laihems code
36 //
37 // Creation date: 16.08.2006
38 //
39 
41 #include "G4PhysicalConstants.hh"
42 
45 // screening function lookup table;
46 
47 
49 {
50  if (!scrnInitialized) {
51  SCRN [1][1]= 0.5 ; SCRN [2][1] = 0.0145;
52  SCRN [1][2]= 1.0 ; SCRN [2][2] = 0.0490;
53  SCRN [1][3]= 2.0 ; SCRN [2][3] = 0.1400;
54  SCRN [1][4]= 4.0 ; SCRN [2][4] = 0.3312;
55  SCRN [1][5]= 8.0 ; SCRN [2][5] = 0.6758;
56  SCRN [1][6]= 15.0 ; SCRN [2][6] = 1.126;
57  SCRN [1][7]= 20.0 ; SCRN [2][7] = 1.367;
58  SCRN [1][8]= 25.0 ; SCRN [2][8] = 1.564;
59  SCRN [1][9]= 30.0 ; SCRN [2][9] = 1.731;
60  SCRN [1][10]= 35.0 ; SCRN [2][10]= 1.875;
61  SCRN [1][11]= 40.0 ; SCRN [2][11]= 2.001;
62  SCRN [1][12]= 45.0 ; SCRN [2][12]= 2.114;
63  SCRN [1][13]= 50.0 ; SCRN [2][13]= 2.216;
64  SCRN [1][14]= 60.0 ; SCRN [2][14]= 2.393;
65  SCRN [1][15]= 70.0 ; SCRN [2][15]= 2.545;
66  SCRN [1][16]= 80.0 ; SCRN [2][16]= 2.676;
67  SCRN [1][17]= 90.0 ; SCRN [2][17]= 2.793;
68  SCRN [1][18]= 100.0 ; SCRN [2][18]= 2.897;
69  SCRN [1][19]= 120.0 ; SCRN [2][19]= 3.078;
70 
71  scrnInitialized=true;
72  }
73 }
74 
76 {
77  InitializeMe();
78 }
79 
80 
82  G4double aLept0E, G4double aGammaE, G4double sintheta,
83  const G4StokesVector & beamPol,
84  const G4StokesVector & /*p1*/,
85  G4int /*flag*/)
86 {
87 // G4cout<<"G4PolarizedBremsstrahlungCrossSection::Initialize \n"
88 // <<"lepE = "<<aLept0E
89 // <<"gamE = "<<aGammaE
90 // <<"sint = "<<sintheta<<"\n"
91 // <<"beamPol="<<beamPol<<"\n";
92 
93  G4double aLept1E = aLept0E - aGammaE;
94 
95  G4double Stokes_S1 = beamPol.x() ;
96  G4double Stokes_S2 = beamPol.y() ;
97  G4double Stokes_S3 = beamPol.z() ;
98  // **************************************************************************
99 
100  G4double m0_c2 = electron_mass_c2;
101  G4double Lept0E = aLept0E/m0_c2+1., Lept0E2 = Lept0E * Lept0E ;
102  G4double GammaE = aGammaE/m0_c2, GammaE2 = GammaE * GammaE ;
103  G4double Lept1E = aLept1E/m0_c2+1., Lept1E2 = Lept1E * Lept1E ;
104 
105 
106  // const G4Element* theSelectedElement = theModel->SelectedAtom();
107 
108  // ******* Gamma Transvers Momentum
109 
110  G4double TMom = std::sqrt(Lept0E2 -1.)* sintheta;
111  G4double u = TMom , u2 =u * u ;
112  G4double Xsi = 1./(1.+u2) , Xsi2 = Xsi * Xsi ;
113 
114  // G4double theZ = theSelectedElement->GetZ();
115 
116  // G4double fCoul = theSelectedElement->GetfCoulomb();
117  G4double delta = 12. * std::pow(theZ, 1./3.) *
118  Lept0E * Lept1E * Xsi / (121. * GammaE);
119  G4double GG=0.;
120 
121  if(delta < 0.5) {
122  GG = std::log(2.* Lept0E * Lept1E / GammaE) - 2. - fCoul;
123  }
124  else if ( delta < 120) {
125  for (G4int j=2; j<=19; j++) {
126  if(SCRN[1][j] >= delta) {
127  GG =std::log(2 * Lept0E * Lept1E / GammaE) - 2 - fCoul
128  -(SCRN[2][j-1]+(delta-SCRN[1][j-1])*(SCRN[2][j]-SCRN[2][j-1])
129  /(SCRN[1][j]-SCRN[1][j-1]));
130  break;
131  }
132  }
133  }
134  else {
135  G4double alpha_sc = (111 * std::pow(theZ, -1./3.)) / Xsi;
136  GG = std::log(alpha_sc)- 2 - fCoul;
137  }
138 
139  if(GG<-1) GG=-1; // *KL* do we need this ?!
140 
141  G4double I_Lept = (Lept0E2 + Lept1E2) * (3.+2.*GG) - 2 * Lept0E * Lept1E * (1. + 4. * u2 * Xsi2 * GG);
142  G4double F_Lept = Lept1E * 4. * GammaE * u * Xsi * (1. - 2 * Xsi) * GG / I_Lept;
143  G4double E_Lept = Lept0E * 4. * GammaE * u * Xsi * (2. * Xsi - 1.) * GG / I_Lept;
144  G4double M_Lept = 4. * Lept0E * Lept1E * (1. + GG - 2. * Xsi2 * u2 * GG) / I_Lept ;
145  G4double P_Lept = GammaE2 * (1. + 8. * GG * (Xsi - 0.5)*(Xsi - 0.5)) / I_Lept ;
146 
147  G4double Stokes_SS1 = M_Lept * Stokes_S1 + E_Lept * Stokes_S3;
148  G4double Stokes_SS2 = M_Lept * Stokes_S2 ;
149  G4double Stokes_SS3 = (M_Lept + P_Lept) * Stokes_S3 + F_Lept * Stokes_S1;
150 
151  theFinalLeptonPolarization.setX(Stokes_SS1);
152  theFinalLeptonPolarization.setY(Stokes_SS2);
153  theFinalLeptonPolarization.setZ(Stokes_SS3);
154 
155  if(theFinalLeptonPolarization.mag2()>1) {
156  G4cout<<" WARNING in pol-brem theFinalLeptonPolarization \n";
157  G4cout
159  <<"\t GG\t"<<GG
160  <<"\t delta\t"<<delta
161  <<G4endl;
164  theFinalLeptonPolarization.setZ(Stokes_SS3);
165  if(Stokes_SS3>1) theFinalLeptonPolarization.setZ(1);
166  }
167 
168 
169  G4double I_Gamma = (Lept0E2 + Lept1E2)*(3+2*GG) - 2 * Lept0E * Lept1E * (1 + 4 * u2 * Xsi2 * GG);
170  G4double D_Gamma = 8 * Lept0E * Lept1E * u2 * Xsi2 * GG / I_Gamma;
171  G4double L_Gamma = GammaE * ((Lept0E + Lept1E) * (3 + 2 * GG)
172  - 2 * Lept1E * (1 + 4 * u2 * Xsi2 * GG))/I_Gamma;
173  G4double T_Gamma = 4 * GammaE * Lept1E * Xsi * u * (2 * Xsi - 1) * GG / I_Gamma ;
174 
175  G4double Stokes_P1 = D_Gamma ;
176  G4double Stokes_P2 = 0 ;
177  G4double Stokes_P3 = (Stokes_S3*L_Gamma + Stokes_S1*T_Gamma) ;
178 
180 
181  theFinalGammaPolarization.setX(Stokes_P1);
182  theFinalGammaPolarization.setY(Stokes_P2);
183  theFinalGammaPolarization.setZ(Stokes_P3);
184 
185  if(theFinalGammaPolarization.mag2()>1) {
186  G4cout<<" WARNING in pol-brem theFinalGammaPolarization \n";
187  G4cout
189  <<"\t GG\t"<<GG
190  <<"\t delta\t"<<delta
191  <<G4endl;
192  }
193 }
194 
196  const G4StokesVector & /*pol3*/)
197 {
198  G4cout<<"ERROR dummy routine G4PolarizedBremsstrahlungCrossSection::XSection called \n";
199  return 0;
200 }
201 
202  // return expected mean polarisation
204 {
205  // electron/positron
207 }
209 {
210  // photon
212 }
213 
214 
virtual G4double XSection(const G4StokesVector &pol2, const G4StokesVector &pol3)
int G4int
Definition: G4Types.hh:78
G4GLOB_DLL std::ostream G4cout
bool G4bool
Definition: G4Types.hh:79
virtual void Initialize(G4double eps, G4double X, G4double phi, const G4StokesVector &p0, const G4StokesVector &p1, G4int flag=0)
#define G4endl
Definition: G4ios.hh:61
double G4double
Definition: G4Types.hh:76