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26 // -------------------------------------------
27 //
28 // Geant4 class file
29 //
30 // File name: G4PolarizedBremsstrahlungXS
31 //
32 // Author: Andreas Schaelicke on the ba
33
34 #include "G4PolarizedBremsstrahlungXS.hh"
35
36 #include "G4PhysicalConstants.hh"
37
38 G4double G4PolarizedBremsstrahlungXS::SCRN[2][
39 { 0.5, 1.0, 2.0, 4.0, 8.0, 15.0, 20.0, 25.0,
40 60.0, 70.0, 80.0, 90.0, 100.0, 120.0 },
41 { 0.0145, 0.0490, 0.1400, 0.3312, 0.6758, 1.
42 2.001, 2.114, 2.216, 2.393, 2.545, 2.676,
43 };
44
45 G4PolarizedBremsstrahlungXS::G4PolarizedBremss
46 {
47 fFinalLeptonPolarization = G4StokesVector::Z
48 fFinalGammaPolarization = G4StokesVector::Z
49 }
50
51 G4PolarizedBremsstrahlungXS::~G4PolarizedBrems
52
53 void G4PolarizedBremsstrahlungXS::Initialize(G
54 G
55 c
56 c
57 G
58 {
59 G4double aLept1E = aLept0E - aGammaE;
60
61 G4double Stokes_S1 = beamPol.x();
62 G4double Stokes_S2 = beamPol.y();
63 G4double Stokes_S3 = beamPol.z();
64
65 G4double Lept0E = aLept0E / electron_mass_c
66 G4double Lept0E2 = Lept0E * Lept0E;
67 G4double GammaE = aGammaE / electron_mass_c
68 G4double GammaE2 = GammaE * GammaE;
69 G4double Lept1E = aLept1E / electron_mass_c
70 G4double Lept1E2 = Lept1E * Lept1E;
71
72 // ******* Gamma Transverse Momentum
73 G4double TMom = std::sqrt(Lept0E2 - 1.) * si
74 G4double u = TMom;
75 G4double u2 = u * u;
76 G4double Xsi = 1. / (1. + u2);
77 G4double Xsi2 = Xsi * Xsi;
78
79 G4double delta =
80 12. * std::pow(fZ, 1. / 3.) * Lept0E * Lep
81
82 G4double GG = 0.;
83 if(delta < 0.5)
84 {
85 GG = std::log(2. * Lept0E * Lept1E / Gamma
86 }
87 else if(delta < 120)
88 {
89 for(G4int j = 1; j < 19; ++j)
90 {
91 if(SCRN[0][j] >= delta)
92 {
93 GG = std::log(2 * Lept0E * Lept1E / Ga
94 (SCRN[1][j - 1] + (delta - SCRN[0
95 (SCRN[1][j] -
96 (SCRN[0][j] -
97 break;
98 }
99 }
100 }
101 else
102 {
103 G4double alpha_sc = (111. * std::pow(fZ, -
104 GG = std::log(alpha_sc) - 2
105 }
106
107 if(GG < -1.)
108 GG = -1.;
109
110 G4double I_Lept = (Lept0E2 + Lept1E2) * (3.
111 2 * Lept0E * Lept1E * (1.
112 G4double F_Lept =
113 Lept1E * 4. * GammaE * u * Xsi * (1. - 2 *
114 G4double E_Lept =
115 Lept0E * 4. * GammaE * u * Xsi * (2. * Xsi
116 G4double M_Lept =
117 4. * Lept0E * Lept1E * (1. + GG - 2. * Xsi
118 G4double P_Lept =
119 GammaE2 * (1. + 8. * GG * (Xsi - 0.5) * (X
120
121 G4double Stokes_SS1 = M_Lept * Stokes_S1 + E
122 G4double Stokes_SS2 = M_Lept * Stokes_S2;
123 G4double Stokes_SS3 = (M_Lept + P_Lept) * St
124
125 fFinalLeptonPolarization.setX(Stokes_SS1);
126 fFinalLeptonPolarization.setY(Stokes_SS2);
127 fFinalLeptonPolarization.setZ(Stokes_SS3);
128
129 if(fFinalLeptonPolarization.mag2() > 1.)
130 {
131 G4ExceptionDescription ed;
132 ed << " WARNING in pol-brem fFinalLeptonPo
133 ed << "\t" << fFinalLeptonPolarization <<
134 << delta;
135 G4Exception("G4PolarizedBremsstrahlungXS::
136 JustWarning, ed);
137 fFinalLeptonPolarization.setX(0);
138 fFinalLeptonPolarization.setY(0);
139 fFinalLeptonPolarization.setZ(Stokes_SS3);
140 if(Stokes_SS3 > 1)
141 fFinalLeptonPolarization.setZ(1);
142 }
143
144 G4double I_Gamma = (Lept0E2 + Lept1E2) * (3.
145 2. * Lept0E * Lept1E * (1
146 G4double D_Gamma = 8. * Lept0E * Lept1E * u2
147 G4double L_Gamma = GammaE *
148 ((Lept0E + Lept1E) * (3.
149 2. * Lept1E * (1. + 4. *
150 I_Gamma;
151 G4double T_Gamma =
152 4. * GammaE * Lept1E * Xsi * u * (2. * Xsi
153
154 G4double Stokes_P1 = D_Gamma;
155 G4double Stokes_P2 = 0.;
156 G4double Stokes_P3 = (Stokes_S3 * L_Gamma +
157
158 fFinalGammaPolarization.SetPhoton();
159
160 fFinalGammaPolarization.setX(Stokes_P1);
161 fFinalGammaPolarization.setY(Stokes_P2);
162 fFinalGammaPolarization.setZ(Stokes_P3);
163
164 if(fFinalGammaPolarization.mag2() > 1.)
165 {
166 G4ExceptionDescription ed;
167 ed << " WARNING in pol-brem fFinalGammaPol
168 ed << "\t" << fFinalGammaPolarization << "
169 << delta;
170 G4Exception("G4PolarizedBremsstrahlungXS::
171 JustWarning, ed);
172 }
173 }
174
175 G4double G4PolarizedBremsstrahlungXS::XSection
176
177 {
178 G4ExceptionDescription ed;
179 ed << "ERROR dummy routine G4PolarizedBremss
180 "called.\n";
181 G4Exception("G4PolarizedBremsstrahlungXS::XS
182 ed);
183
184 return 0.;
185 }
186
187 // return expected mean polarisation
188 G4StokesVector G4PolarizedBremsstrahlungXS::Ge
189 {
190 // electron/positron
191 return fFinalLeptonPolarization;
192 }
193
194 G4StokesVector G4PolarizedBremsstrahlungXS::Ge
195 {
196 // photon
197 return fFinalGammaPolarization;
198 }
199