[819] | 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: $ |
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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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