1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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4 | // * * |
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5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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7 | // * conditions of the Geant4 Software License, included in the file * |
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8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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9 | // * include a list of copyright holders. * |
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10 | // * * |
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11 | // * Neither the authors of this software system, nor their employing * |
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12 | // * institutes,nor the agencies providing financial support for this * |
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13 | // * work make any representation or warranty, express or implied, * |
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14 | // * regarding this software system or assume any liability for its * |
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15 | // * use. Please see the license in the file LICENSE and URL above * |
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16 | // * for the full disclaimer and the limitation of liability. * |
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17 | // * * |
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18 | // * This code implementation is the result of the scientific and * |
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19 | // * technical work of the GEANT4 collaboration. * |
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20 | // * By using, copying, modifying or distributing the software (or * |
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21 | // * any work based on the software) you agree to acknowledge its * |
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22 | // * use in resulting scientific publications, and indicate your * |
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23 | // * acceptance of all terms of the Geant4 Software license. * |
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24 | // ******************************************************************** |
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25 | // |
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26 | // |
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27 | // $Id: G4StrawTubeXTRadiator.cc,v 1.6 2007/09/29 17:49:34 vnivanch Exp $ |
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28 | // GEANT4 tag $Name: geant4-09-02-ref-02 $ |
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29 | // |
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30 | |
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31 | #include "G4StrawTubeXTRadiator.hh" |
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32 | #include "Randomize.hh" |
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33 | #include "G4Gamma.hh" |
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34 | |
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35 | using namespace std; |
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36 | |
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37 | //////////////////////////////////////////////////////////////////////////// |
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38 | // |
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39 | // Constructor, destructor |
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40 | |
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41 | G4StrawTubeXTRadiator::G4StrawTubeXTRadiator(G4LogicalVolume *anEnvelope, |
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42 | G4Material* foilMat,G4Material* gasMat, |
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43 | G4double a, G4double b, G4Material* mediumMat, |
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44 | G4bool unishut, |
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45 | const G4String& processName) : |
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46 | G4VXTRenergyLoss(anEnvelope,foilMat,gasMat,a,b,1,processName) |
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47 | { |
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48 | if(verboseLevel > 0) |
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49 | G4cout<<"Straw tube X-ray TR radiator EM process is called"<<G4endl; |
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50 | |
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51 | if( unishut ) |
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52 | { |
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53 | fAlphaPlate = 1./3.; |
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54 | fAlphaGas = 12.4; |
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55 | if(verboseLevel > 0) |
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56 | G4cout<<"straw uniform shooting: "<<"fAlphaPlate = " |
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57 | <<fAlphaPlate<<" ; fAlphaGas = "<<fAlphaGas<<G4endl; |
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58 | |
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59 | } |
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60 | else |
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61 | { |
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62 | fAlphaPlate = 0.5; |
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63 | fAlphaGas = 5.; |
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64 | if(verboseLevel > 0) |
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65 | G4cout<<"straw isotropical shooting: "<<"fAlphaPlate = " |
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66 | <<fAlphaPlate<<" ; fAlphaGas = "<<fAlphaGas<<G4endl; |
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67 | |
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68 | |
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69 | } |
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70 | // index of medium material |
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71 | |
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72 | fMatIndex3 = mediumMat->GetIndex(); |
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73 | if(verboseLevel > 0) |
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74 | G4cout<<"medium material = "<<mediumMat->GetName()<<G4endl; |
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75 | |
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76 | // plasma energy squared for plate material |
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77 | |
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78 | fSigma3 = fPlasmaCof*mediumMat->GetElectronDensity(); |
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79 | if(verboseLevel > 0) |
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80 | G4cout<<"medium plasma energy = "<<sqrt(fSigma3)/eV<<" eV"<<G4endl; |
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81 | |
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82 | // Compute cofs for preparation of linear photo absorption in external medium |
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83 | |
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84 | ComputeMediumPhotoAbsCof(); |
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85 | |
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86 | // Build energy and angular integral spectra of X-ray TR photons from |
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87 | // a radiator |
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88 | |
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89 | // BuildTable(); |
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90 | } |
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91 | |
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92 | /////////////////////////////////////////////////////////////////////////// |
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93 | |
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94 | G4StrawTubeXTRadiator::~G4StrawTubeXTRadiator() |
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95 | { |
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96 | } |
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97 | |
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98 | /////////////////////////////////////////////////////////////////////////// |
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99 | // |
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100 | // Approximation for radiator interference factor for the case of |
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101 | // straw tube radiator. The plate (window, straw wall) and gas (inside straw) |
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102 | // gap thicknesses are gamma distributed. |
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103 | // The mean values of the plate and gas gap thicknesses |
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104 | // are supposed to be about XTR formation zone. |
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105 | |
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106 | G4double |
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107 | G4StrawTubeXTRadiator::GetStackFactor( G4double energy, |
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108 | G4double gamma, G4double varAngle ) |
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109 | { |
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110 | |
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111 | |
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112 | G4double result, L2, L3, M2, M3; |
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113 | |
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114 | L2 = GetPlateFormationZone(energy,gamma,varAngle); |
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115 | L3 = GetGasFormationZone(energy,gamma,varAngle); |
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116 | |
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117 | M2 = GetPlateLinearPhotoAbs(energy); |
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118 | M3 = GetGasLinearPhotoAbs(energy); |
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119 | |
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120 | G4complex C2(1.0 + 0.5*fPlateThick*M2/fAlphaPlate, fPlateThick/L2/fAlphaPlate); |
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121 | G4complex C3(1.0 + 0.5*fGasThick*M3/fAlphaGas, fGasThick/L3/fAlphaGas); |
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122 | |
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123 | G4complex H2 = pow(C2,-fAlphaPlate); |
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124 | G4complex H3 = pow(C3,-fAlphaGas); |
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125 | G4complex H = H2*H3; |
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126 | |
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127 | G4complex Z1 = GetMediumComplexFZ(energy,gamma,varAngle); |
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128 | G4complex Z2 = GetPlateComplexFZ(energy,gamma,varAngle); |
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129 | G4complex Z3 = GetGasComplexFZ(energy,gamma,varAngle); |
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130 | |
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131 | |
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132 | G4complex R = ( Z1 - Z2 )*( Z1 - Z2 )*( 1. - H2*H ) + |
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133 | ( Z2 - Z3 )*( Z2 - Z3 )*( 1. - H3 ) + |
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134 | 2.*( Z1 - Z2 )*( Z2 - Z3 )*H2*( 1. - H3 ) ; |
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135 | |
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136 | result = 2.0*real(R)*(varAngle*energy/hbarc/hbarc); |
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137 | |
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138 | return result; |
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139 | |
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140 | } |
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141 | |
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142 | |
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143 | ////////////////////////////////////////////////////////////////////// |
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144 | ////////////////////////////////////////////////////////////////////// |
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145 | ////////////////////////////////////////////////////////////////////// |
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146 | // |
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147 | // Calculates formation zone for external medium. Omega is energy !!! |
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148 | |
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149 | G4double G4StrawTubeXTRadiator::GetMediumFormationZone( G4double omega , |
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150 | G4double gamma , |
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151 | G4double varAngle ) |
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152 | { |
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153 | G4double cof, lambda; |
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154 | lambda = 1.0/gamma/gamma + varAngle + fSigma3/omega/omega; |
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155 | cof = 2.0*hbarc/omega/lambda ; |
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156 | return cof ; |
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157 | } |
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158 | |
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159 | ////////////////////////////////////////////////////////////////////// |
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160 | // |
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161 | // Calculates complex formation zone for external medium. Omega is energy !!! |
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162 | |
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163 | G4complex G4StrawTubeXTRadiator::GetMediumComplexFZ( G4double omega , |
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164 | G4double gamma , |
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165 | G4double varAngle ) |
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166 | { |
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167 | G4double cof, length,delta, real, image; |
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168 | |
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169 | length = 0.5*GetMediumFormationZone(omega,gamma,varAngle); |
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170 | delta = length*GetMediumLinearPhotoAbs(omega); |
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171 | cof = 1.0/(1.0 + delta*delta); |
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172 | |
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173 | real = length*cof; |
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174 | image = real*delta; |
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175 | |
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176 | G4complex zone(real,image); |
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177 | return zone; |
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178 | } |
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179 | |
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180 | //////////////////////////////////////////////////////////////////////// |
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181 | // |
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182 | // Computes matrix of Sandia photo absorption cross section coefficients for |
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183 | // medium material |
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184 | |
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185 | void G4StrawTubeXTRadiator::ComputeMediumPhotoAbsCof() |
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186 | { |
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187 | const G4MaterialTable* theMaterialTable = G4Material::GetMaterialTable(); |
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188 | const G4Material* mat = (*theMaterialTable)[fMatIndex3]; |
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189 | fMediumPhotoAbsCof = mat->GetSandiaTable(); |
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190 | } |
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191 | |
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192 | ////////////////////////////////////////////////////////////////////// |
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193 | // |
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194 | // Returns the value of linear photo absorption coefficient (in reciprocal |
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195 | // length) for medium for given energy of X-ray photon omega |
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196 | |
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197 | G4double G4StrawTubeXTRadiator::GetMediumLinearPhotoAbs(G4double omega) |
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198 | { |
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199 | G4double omega2, omega3, omega4; |
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200 | |
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201 | omega2 = omega*omega; |
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202 | omega3 = omega2*omega; |
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203 | omega4 = omega2*omega2; |
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204 | |
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205 | G4double* SandiaCof = fMediumPhotoAbsCof->GetSandiaCofForMaterial(omega); |
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206 | |
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207 | G4double cross = SandiaCof[0]/omega + SandiaCof[1]/omega2 + |
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208 | SandiaCof[2]/omega3 + SandiaCof[3]/omega4; |
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209 | return cross; |
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210 | } |
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211 | |
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212 | // |
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213 | // |
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214 | //////////////////////////////////////////////////////////////////////////// |
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215 | |
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216 | |
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222 | |
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