| 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 | // $Id: G4ModifiedTsai.cc,v 1.1 2010/10/14 15:17:48 vnivanch Exp $
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| 27 | // GEANT4 tag $Name: emstand-V09-03-24 $
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| 28 | //
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| 29 | // -------------------------------------------------------------------
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| 30 | //
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| 31 | // GEANT4 Class file
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| 32 | //
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| 33 | //
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| 34 | // File name: G4ModifiedTsai
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| 35 | //
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| 36 | // Author: Andreia Trindade (andreia@lip.pt)
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| 37 | // Pedro Rodrigues (psilva@lip.pt)
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| 38 | // Luis Peralta (luis@lip.pt)
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| 39 | //
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| 40 | // Creation date: 21 March 2003
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| 41 | //
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| 42 | // Modifications:
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| 43 | // 21 Mar 2003 A.Trindade First implementation acording with new design
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| 44 | // 24 Mar 2003 A.Trindade Fix in Tsai generator in order to prevent theta
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| 45 | // generation above pi
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| 46 | // 13 Oct 2010 V.Ivanchenko Moved to standard and improved comment
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| 47 | //
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| 48 | // Class Description:
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| 49 | //
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| 50 | // Bremsstrahlung Angular Distribution Generation
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| 51 | // suggested by L.Urban (Geant3 manual (1993) Phys211)
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| 52 | // Derived from Tsai distribution (Rev Mod Phys 49,421(1977))
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| 53 | //
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| 54 | // Class Description: End
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| 55 | //
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| 56 | // -------------------------------------------------------------------
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| 57 | //
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| 58 |
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| 59 | #include "G4ModifiedTsai.hh"
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| 60 | #include "Randomize.hh"
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| 61 |
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| 62 | G4ModifiedTsai::G4ModifiedTsai(const G4String&)
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| 63 | : G4VBremAngularDistribution("AngularGenUrban")
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| 64 | {}
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| 65 |
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| 66 | G4ModifiedTsai::~G4ModifiedTsai()
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| 67 | {}
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| 68 |
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| 69 | G4double G4ModifiedTsai::PolarAngle(const G4double initial_energy,
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| 70 | const G4double, // final_energy
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| 71 | const G4int ) // Z
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| 72 | {
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| 73 | // Sample gamma angle (Z - axis along the parent particle).
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| 74 | // Universal distribution suggested by L. Urban (Geant3 manual (1993)
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| 75 | // Phys211) derived from Tsai distribution (Rev Mod Phys 49,421(1977))
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| 76 |
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| 77 | G4double totalEnergy = initial_energy + electron_mass_c2;
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| 78 |
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| 79 | const G4double a1 = 0.625, a2 = 3.*a1, d = 27.;
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| 80 | G4double u, theta = 0;
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| 81 |
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| 82 | do{
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| 83 | u = - std::log(G4UniformRand()*G4UniformRand());
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| 84 |
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| 85 | if (9./(9.+d) > G4UniformRand()) { u /= a1; }
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| 86 | else { u /= a2; }
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| 87 |
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| 88 | theta = u*electron_mass_c2/totalEnergy;
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| 89 | } while(u*electron_mass_c2 > totalEnergy*pi);
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| 90 |
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| 91 | return theta;
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| 92 | }
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| 93 |
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| 94 | void G4ModifiedTsai::PrintGeneratorInformation() const
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| 95 | {
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| 96 | G4cout << "\n" << G4endl;
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| 97 | G4cout << "Bremsstrahlung Angular Generator is Modified Tsai" << G4endl;
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| 98 | G4cout << "Distribution suggested by L.Urban (Geant3 manual (1993) Phys211)"
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| 99 | << G4endl;
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| 100 | G4cout << "Derived from Tsai distribution (Rev Mod Phys 49,421(1977)) \n"
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| 101 | << G4endl;
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| 102 | }
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